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Type 2 diabetes mellitus (T2DM) is a metabolic disorder that is characterized by insulin resistance and hyperglycemia. It is also known to be a risk factor for Alzheimer's disease (AD). Insulin plays a crucial role in regulating the body's metabolism and is responsible for activating the Phosphoinotide-3-Kinase (PI3K)/Protein Kinase B (Akt) signaling pathway. This pathway is activated when insulin binds to the insulin receptor on nerve cells, and it helps regulate the metabolism of glucose and lipids. Dysfunction in the insulin signaling pathway can lead to a decrease in brain insulin levels and insulin sensitivity, thereby inducing disruptions in insulin signal transduction and leading to disorders in brain energy metabolism. Moreover, these dysfunctions also contribute to the accumulation of β-amyloid (Aβ) deposition and the hyperphosphorylation of Tau protein, both of which are characteristic features of AD. Therefore, this article focuses on insulin resistance to reveal the complex mechanism between brain insulin resistance and AD occurrence in T2DM. On this basis, this article further summarizes the biological effects and mechanisms of antidiabetic drugs on the two diseases, aiming to provide new ideas for the discovery of drugs for the treatment of T2DM combined with AD., Competing Interests: Declarations. Ethics approval and consent to participate: This article does not contain any studies with human participants or animals performed by any of the authors. Consent for publication: All of the authors consent for publication. Competing interests: The authors declare no competing interests. Abbreviations: T2DM Type 2 diabetes mellitus AD Alzheimer’s disease PI3K Phosphoinotide-3-Kinase Akt Protein Kinase B Aβ β-amyloid PTK Protein Tyrosine Kinase SH2 Src homology domain 2 GLUT4 glucose transporter 4 GSK-3 glycogen synthase kinase-3 IRS insulin receptor substrates GS Glycogen synthetase FOXO1 forkhead box O1 CREB cAMP-response elementbinding FFA Free Fatty Acid TNF-α Tumor Necrosis Factor-α IL-6 Interleukin-6 IL-1β Interleukin-1β CRP C-reactive Protein PKC Protein kinase C DAG diacylglycerol JNK c-jun N-terminal kinase BBB blood-brain barrier NFT neurofibrillary tangles IDE insulin degrading enzymes IGF insulin-like growth factor ChAT choline acetyltransferase ApoE apolipoprotein E BACE1 Beta-secretase 1 APP amyloid precursor protein GLP-1 Glucagon-like peptide-1 TZD Thiazolidinediones PPARs peroxisome proliferator-activated receptor gamma DPP-4 Dipeptidyl-peptidase IV GIP glucose-dependent insulinotropic peptide HFD high-fat diet, (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Erectile dysfunction (ED) has been linked to insulin resistance (IR), with various surrogate indices being used to assess this association. This systematic review and meta-analysis aimed to evaluate the relationship between IR indices and the incidence and severity of ED., Methods: A comprehensive search across PubMed, Embase, Web of Science, and Scopus was carried out. Required data were extracted and meta-analyzed. The Newcastle-Ottawa Scale (NOS) was employed to evaluate the studies' risk of bias. Sensitivity analyses and meta-regressions were conducted to explore heterogeneity and the impact of confounding variables., Results: Seventeen studies with a total of 3810 patients with ED and 8252 without ED were included. Meta-analysis revealed that males with ED had significantly higher levels of Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) (SMD = 0.59, 95% CI [0.15, 1.03], I 2  = 82%, P < 0.01), Triglyceride-Glucose Index (TyG) (SMD = 0.53, 95% CI [0.31, 0.75], I 2  = 69%, P < 0.01), and Visceral Adiposity Index (VAI) (SMD = 0.45, 95% CI [0.25, 0.64], I 2  = 76%, P < 0.01) compared to those without ED. However, there was no significant correlation between a one-unit increase in HOMA-IR (OR = 0.63, 95% CI [0.03, 13.69], I 2  = 91%, P = 0.77) or TyG (OR = 0.53, 95% CI [0.02, 11.53], I 2  = 88%, P = 0.68) and the odds of ED. Additionally, a one-unit increase in VAI was associated with more severe ED (SMD = 0.34, 95% CI [0.03, 0.64], I 2  = 16%, P = 0.03). The diagnostic accuracy of these indices varied., Conclusions: The results indicate a significant connection between insulin resistance and erectile dysfunction, as shown by HOMA-IR, TyG, and VAI. Yet, their usefulness in predicting ED is restricted because of significant differences and inconsistencies in diagnostic precision. More research is required to determine the clinical importance of these indices in treating ED., Competing Interests: Declarations Ethics approval and consent to participate Not applicable. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Polycystic ovary syndrome (PCOS) is a primary endocrinological disorder in women of reproductive age that is characterized by androgen excess and ovulatory irregularities. This syndrome is associated with adipose tissue dysfunction, an elevated risk of insulin resistance, hyperinsulinemia, obesity, and type 2 diabetes. Adipocyte dysfunction affects the secretion of adipokines and pro-inflammatory cytokines. Nevertheless, adipose tissue is not an exclusive source of adipokines as it can also be produced locally by reproductive tissues. Although adipokines have been recognized in the development of PCOS, the role of oncostatin M (OSM), a multifaceted adipokine, remains unclear. Current evidence suggests that this cytokine is associated with key aspects of the syndrome, including obesity, insulin resistance, hyperandrogenism, and inflammation. However, the data are often contradictory, likely due to variations in study designs, methodologies, and species differences. By investigating the link between OSM and PCOS-associated issues, this review identified the potential role of this adipokine in PCOS pathogenesis. This underscores the need for further research to clarify its predominant effects and assess its relevance as a therapeutic target.

Background: The majority of Chinese Americans is foreign-born, and it is well-documented that immigration to the United States (US) leads to increased risk for chronic diseases including type 2 diabetes. Increased disease risk has been attributed to changes in lifestyle behaviors following immigration, but few studies have considered the psychosocial impact of immigration upon biomarkers of disease risk., Purpose: To examine associations of psychological stress and social isolation with markers of type 2 diabetes risk over time among US Chinese immigrants., Methods: In this longitudinal study of 614 Chinese immigrants, participants completed assessments of perceived stress, acculturative stress, negative life events, and social isolation annually at three time points. Fasting blood samples were obtained at each time point to measure blood glucose, glycated hemoglobin, and insulin resistance. Mean duration between baseline and follow-up assessments was approximately 2 years., Results: Increases in migration-related stress, perceived stress and social isolation were associated with significant increases in fasting glucose at follow-up independent of age, body mass index, length of US residence, and other potential covariates. Moreover, increases in glucose varied depending on perceived stress levels at baseline, such that those with higher baseline stress had a steeper increase in glucose over time., Conclusions: Psychological stress and social isolation are associated with increases in fasting glucose in a sample of US Chinese immigrants. Findings suggest that the unique experiences of immigration may be involved in the risk of developing type 2 diabetes, a condition that is prevalent among US Chinese despite relatively low rates of obesity., (© Society of Behavioral Medicine 2024. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Objective: An alternative metric for evaluating insulin resistance (IR) is the triglyceride glucose-body mass index (TyG-BMI). However, it is yet unclear how TyG-BMI and suicide attempts (SA) are related. The objective of this research was to explore the correlation between the TyG-BMI index and SA in individuals with untreated first-episode (UFE) major depressive disorder (MDD) in Shanxi Province., Methods: This cross-sectional study was conducted from September 2016 to December 2018 in the psychiatric outpatient clinic of Taiyuan General Hospital and included 1718 patients with UFE MDD, with a mean age of 34.9 ± 12.4 years. The relationship between TyG-BMI and SA was assessed using logistic regression modeling. We investigated threshold effects using a two-piecewise linear regression model., Results: Taking into consideration the potential influence of confounding variables, a comprehensive multivariate logistic regression analysis was conducted, which demonstrated the absence of a statistically significant association between the TyG-BMI index and the occurrence of SA, as evidenced by P-values that were all greater than 0.05. On the other hand, the visual analysis of the smoothed plots revealed a U-shaped relationship between the TyG-BMI index and the incidence of SA, with a notable inflection occurring at a TyG-BMI value of around 210. It was observed that the effect sizes flanking the inflection point, accompanied by their 95% confidence intervals, were 0.985 (95% CI: 0.972 to 0.999, P = 0.031) and 1.012 (95% CI: 1.003 to 1.047, P = 0.005), respectively., Conclusions: In UFE MDD patients, a U-shaped link was observed between TyG-BMI and SA, with the minimal SA incidence noted at a TyG-BMI level of 210, signifying that an augmented risk for SA might be connected to both diminished and augmented TyG-BMI levels., Competing Interests: Declarations Ethics approval and consent to participate The research involving human subjects received approval from the Institutional Review Board of the First Hospital, Shanxi Medical University (No. 2016-Y27). All studies were conducted in compliance with local laws and institutional guidelines. Participants provided their written informed consent to take part in the study. Additionally, written informed consent was obtained from the individual(s) for the publication of any potentially identifiable images or data included in this article. Consent for publication Not application. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

This study investigated the effects of 14 days low energy availability (LEA) versus optimal energy availability (OEA) in endurance-trained females on substrate utilization, insulin sensitivity, and skeletal muscle mitochondrial oxidative capacity; and the impact of metabolic changes on exercise performance. Twelve endurance-trained females (V̇O 2max 55.2 ± 5.1 mL × min -1  × kg -1 ) completed two 14-day randomized, blinded, cross-over, controlled dietary interventions: (1) OEA (51.9 ± 2.0 kcal × kg fat-free mass (FFM) -1  × day -1 ) and (2) LEA (22.3 ± 1.5 kcal × kg FFM -1  × day -1 ), followed by 3 days OEA. Participants maintained their exercise training volume during both interventions (approx. 8 h × week -1 at 79% heart rate max). Skeletal muscle mitochondrial respiratory capacity, glycogen, and maximal activity of CS, HAD, and PFK were unaltered with LEA. 20-min time trial endurance performance was impaired by 7.8% (Δ -16.8 W, 95% CI: -23.3 to -10.4, p < .001) which persisted following 3 days refueling post-LEA (p < .001). Fat utilization was increased post-LEA as evidenced by: (1) 99.4% (p < .001) increase in resting plasma free fatty acids (FFA); (2) 270% (p = .007) larger reduction in FFA in response to acute exercise; and (3) 28.2% (p = .015) increase in resting fat oxidation which persisted during submaximal exercise (p < .001). These responses were reversed with 3 days refueling. Daily glucose control (via CGM), HOMA-IR, HOMA-β, were unaffected by LEA. Skeletal muscle O 2 utilization and carbohydrate availability were not limiting factors for aerobic exercise capacity and performance; therefore, whether LEA per se affects aspects of training quality/recovery requires investigation., (© 2024 The Author(s). The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.)

Aim: Insulin resistance (IR) is a pivotal metabolic disorder associated with type 2 diabetes and metabolic syndrome. This study investigated the potential of hypoxanthine (Hx), a purine metabolite and uric acid precursor, in ameliorating IR and regulating hepatic glucose and lipid metabolism., Methods: We utilized both in vitro IR-HepG2 cells and in vivo diet-induced IR mice to investigate the impact of Hx. The HepG2 cells were treated with Hx to evaluate its effects on glucose production and lipid deposition. Activity-based protein profiling (ABPP) was applied to identify Hx-target proteins and the underlying pathways. In vivo studies involved administration of Hx to IR mice, followed by assessments of IR-associated indices, with explores on the potential regulating mechanisms on hepatic glucose and lipid metabolism., Key Findings: Hx intervention significantly reduced glucose production and lipid deposition in a dose-dependent manner without affecting cell viability in IR-HepG2 cells. ABPP identified key Hx-target proteins engaged in fatty acid and pyruvate metabolism. In vivo, Hx treatment reduced IR severities, as evidenced by decreased HOMA-IR, fasting blood glucose, and serum lipid profiles. Histological assessments confirmed reduced liver lipid deposition. Mechanistic insights revealed that Hx suppresses hepatic gluconeogenesis and fatty acid synthesis, and promotes fatty acid oxidation via the AMPK/mTOR/PPARα pathway., Significance: This study delineates a novel role of Hx in regulating hepatic metabolism, offering a potential therapeutic strategy for IR and associated metabolic disorders. The findings provide a foundation for further investigation into the role of purine metabolites in metabolic regulation and their clinical implications., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Angina with Non-Obstructed Coronary Arteries (ANOCA) involves abnormal vasomotor responses. While reduced coronary flow is an established contributor to myocardial hypoxia, myocardial blood volume (MBV) independently regulates myocardial oxygen uptake but its role in ANOCA remains unclear., Objectives: We hypothesized that reduced MBV contributes to ANOCA, and associates with insulin resistance in ANOCA., Methods: MBV in ANOCA patients was compared to age- and sex-matched healthy controls. ANOCA patients underwent coronary angiography with invasive coronary function testing (CFT) to identify vasospasm and coronary microvascular dysfunction. In all subjects MBV was quantified at baseline, during hyperinsulinemia and during dobutamine-induced stress using myocardial contrast echocardiography (MCE). The hyperinsulinemic-euglycemic clamp was used to assess insulin resistance., Results: Twenty-eight ANOCA patients (21% men, 56.8 ± 8.6 years) and 28 healthy controls (21% men, 56.5 ± 7.0 years) were included. During CFT 11% of patients showed epicardial vasospasm, 39% microvascular vasospasm, 25% coronary microvascular dysfunction, and 11% of patients had a negative CFT. ANOCA patients had significant lower insulin-sensitivity (p < 0.01). During MCE, ANOCA patients showed a significantly lower MBV at baseline (0.388 vs 0.438 mL/mL, p = 0.04), during hyperinsulinemia (0.395 vs 0.447 mL/mL, p = 0.02), and during dobutamine-induced stress (0.401 vs 0.476 mL/mL, p = 0.030)., Conclusions: In ANOCA patients MBV is diminished at baseline, during hyperinsulinemia and dobutamine-induced stress in the absence of differences in microvascular recruitment. These findings support the presence of capillary rarefaction in ANOCA patients. ANOCA patients showed metabolic insulin resistance, but insulin did not acutely alter myocardial perfusion., Competing Interests: Declaration of competing interest None declared., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Recent studies have identified a correlation between insulin resistance (IR) and depression. This study aims to explore the correlation between estimated glucose disposal rate (eGDR), a practical and noninvasive measure for assessing IR, and depression in the general population., Methods: In this population-based cross-sectional study, data from 28,444 adults aged 18 years old or older in the NHANES during the period from 1999 to 2018 were analyzed. The correlation between eGDR and depression was examined through multivariate logistic regression analyses, subgroup analyses, restricted cubic spline, and interaction tests. Furthermore, a mediation analysis was conducted to elucidate the role of the atherogenic index of plasma (AIP) in mediating the effect of eGDR on depression., Results: Multivariate logistic regression analysis and restricted cubic splines analysis indicated that eGDR can exhibit a linearly correlation with depression (OR = 0.913; 95% CI: 0.875, 0.953). Subjects in eGDR6-8 and eGDR > 8 groups had a decrease risk of depression as 25.4% and 41.5% than those in the eGDR < 4 group. This negative correlation was more pronounced in those with obesity. Mediation analysis indicated that AIP mediated 9.6% of the correlation between eGDR and depression., Conclusions: eGDR was linear negatively correlated with depression, with AIP playing a mediating role. This study provides a novel perspective on the mechanism connecting IR to depression. Managing IR and monitoring AIP may contribute to alleviating depression., Competing Interests: Declarations Ethics approval and consent to participate The National Center for Health Statistics Ethics Review Board has approved the implementation of NHANES, and every participant signed informed consent. This study also was approved by the Ethics Committee of the Second Affiliated Hospital of Wenzhou Medical University (No. LCKY2023-21, date: Jan 2023). Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Purpose: This study aims to scrutinize the association between various Insulin Resistance (IR) indices and heart failure (HF) risk in adult diabetics within the United States., Methods: The National Health and Nutrition Examination Survey (NHANES) (2005-2018) dataset was used in this study. Weighted logistic regression analysis and restricted cubic spline were employed to ascertain the correlation between IR indices and the incidence of HF in diabetic patients. The predictive capability of the IR indices was evaluated using the Receiver Operating Characteristic curve., Results: This study included a total of 2574 diabetic patients, out of which 209 (8.1%) were diagnosed with HF. After the adjustment of potential confounders, TyG-BMI (OR: 1.005, 95% CI: 1.002-1.009), TG/HDL-C (OR: 1.138, 95% CI: 1.024-1.265), and METS-IR index (OR: 1.035, 95% CI: 1.015-1.057) were significantly associated with HF risk. RCS curves revealed nonlinear dose-response relationship between TyG, TyG-BMI, TG/HDL-C, and the occurrence of HF in diabetic patients. Subgroup analyses showed that four IR indices were positively associated with the risk of HF in the elderly diabetic population. Unfortunately, all IR indices failed to improve the predictive performance of the underlying risk model for HF in diabetic patients., Conclusion: Four IR markers may be important predictors of HF risk in diabetics., (© 2024 The Author(s). Annals of Noninvasive Electrocardiology published by Wiley Periodicals LLC.)

Background: Cognitive decline and dementia are debilitating conditions that compromise the quality of life and charge the healthcare system with a substantial socioeconomic burden. In this context, emerging evidence supports an association between the triglyceride-glucose index (TyG), a surrogate insulin resistance marker, and cognitive decline and dementia. Hence, we systematically reviewed the studies assessing the TyG index in patients with cognitive decline and their controls., Methods: Online international databases (PubMed, Scopus, Embase, and the Web of Science) were searched comprehensively for studies showing the TyG index in patients with cognitive decline/impairment. Random-effect meta-analyses were conducted to calculate the standardized mean difference (SMD), pooled odds ratio (OR), and pooled area under the curve (AUC), in addition to 95% confidence intervals (CIs) for the comparisons of groups., Results: Seventeen studies were included in our analysis. Then, we conducted a meta-analysis, demonstrating that patients with cognitive decline had significantly higher levels of TyG index than those without (SMD 0.83, 95% CI 0.16 to 1.50, p = 0.015). Moreover, our data showed that a 1-unit increase in the TyG index was associated with higher odds of cognitive decline (adjusted OR [aOR] 2.86, 95% CI 1.49 to 5.50, p = 0.002). Further, we observed that patients in the fourth TyG quartile with higher values of the TyG index than the first quartile presented with more increased cognitive decline (aOR 1.62, 95%CI 1.11 to 2.38, p = 0.013). Finally, pooled AUC data for the diagnostic performance of the TyG index resulted in an overall AUC value of 0.73 (95% CI 0.66 to 0.79). Sensitivity and specificity were also calculated as 0.695 and 0.687, respectively., Conclusion: This study supports the clinical utility of the TyG index in patients with cognitive decline and solicits more focused studies to consolidate its usage in clinical settings and real-world practice., (© 2024 The Author(s). Brain and Behavior published by Wiley Periodicals LLC.)

Background: Sarcopenic obesity (SO) and osteoarthritis (OA) are highly prevalent musculoskeletal conditions that significantly impair health-related quality of life., Aim: This study investigated the association between SO and OA, and explored the potential mediating role of insulin resistance in this relationship. We utilized data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018., Methods: This cross-sectional analysis employs NHANES data collected from 1999 to 2018, including participants aged 18 years and older. SO was assessed using dual-energy X-ray absorptiometry (DXA) measurements. Insulin resistance was estimated using the triglyceride-glucose (TyG) index. OA status was based on self-reported physician diagnosis. Statistical analyses included weighted logistic regression, restricted cubic spline (RCS) interaction analysis, mediation analysis using structural equation modeling (SEM), and receiver operating characteristic (ROC) curve analysis. Subgroup analyses were conducted based on age, sex, and diabetes status., Results: The sarcopenic obese group demonstrated the highest prevalence of OA (23.4 %), hypertension (47.8 %), and diabetes (12.0 %). Additionally, they exhibited elevated levels of triglycerides, cholesterol, glucose, blood urea nitrogen (BUN), creatinine, and uric acid. Logistic regression revealed significant positive associations between sarcopenic obesity, the TyG index, and OA risk. RCS analysis identified significant non-linear relationships and interactions of the TyG index with age, sex, and diabetes status on OA risk. Mediation analysis indicated that the TyG index mediated approximately 4.9 % of the effect of sarcopenic obesity on OA risk. ROC curve analysis demonstrated moderate diagnostic accuracy for the TyG index (AUC = 0.65), which improved when incorporated into the multivariate model (AUC = 0.78). Subgroup analyses confirmed significant associations between the TyG index and sarcopenic obesity with OA risk across different age, sex, and diabetes status categories., Conclusion: Our findings suggest a significant correlation between insulin resistance, as measured by the TyG index, and elevated OA risk in individuals with sarcopenic obesity. Targeting insulin resistance through future research may be a promising avenue to lower OA risk in this population., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The association of serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) with insulin resistance (IR), as measured by homeostasis model assessment of insulin resistance (HOMA-IR), in the general population is unclear. Our study aimed to characterize its relationship in a large community-based population. Subjects were recruited from the Danyang city between 2017 and 2019. Serum NT-proBNP was measured using an enhanced chemiluminescence immunoassay. IR was defined by a HOMA-IR in the highest sex-specific quartile. Categorical and continuous analyses were performed with sex-specific NT-proBNP tertiles and naturally logarithmically transformed NT-proBNP (lnNTproBNP), respectively. The 2945 participants (mean age 52.8 years) included 1728 (58.7%) women, 1167 (39.6%) hypertensive patients, 269 (9.1%) diabetic patients, and 736 (25.0%) patients with IR. In simple and multivariate-adjusted regression analyses, serum lnNTproBNP were both negatively associated with HOMA-IR (β = -0.19 to -0.25; p < 0.0001). Similar results were also obtained in multiple subgroup analyses. In multiple logistic regression analyses, elevated serum NT-proBNP was associated with lower risks of IR (odds ratios: 0.68 and 0.39; 95% confidence intervals: 0.61-0.74 and 0.30-0.50 for lnNTproBNP and top vs. bottom tertiles, respectively; p < 0.0001). In conclusion, increased serum NT-proBNP level was strongly associated with a lower risk of IR in Chinese., (© 2024 The Author(s). The Journal of Clinical Hypertension published by Wiley Periodicals LLC.)

Aim: The study aimed to investigate a lipid profile in people with normal glucose tolerance (NGT), NGT and 1hrOGTT > 8.6 mmol/l, and impaired glucose tolerance (IGT); and to assess its association with some cardio-metabolic parameters., Material and Methods: A total of 90 subjects, of mean age 46.7 ± 10.5 years and mean BMI of 32.0 ± 6.3 kg/m 2 were enrolled. They were divided into 3 groups: 19 with NGT, 22 with NGT and 1hrOGTT > 8.6 mmol/l, and 49 with IGT; and subdivided into 2 subgroups according to HOMA-IR: 40 with HOMA-IR < 2.5 and 50 with HOMA-IR ≥ 2.5. Body composition (Inbody 720) and advanced glycation end products (AGE Reader) were assessed. Two functional tests (OGTT; MMTT) were performed and AUC for glucose, insulin and triglycerides were calculated., Results: There was no difference across the glucose tolerance groups for all evaluated lipids. The results showed higher AUC insulin during OGTT (p = 0.037 and 0.020), AUC triglycerides during MMTT (p = 0.048) and triglycerides/HDL ratio (p = 0.064 and 0.016) in the 1hrOGTT and IGT subgroups with HOMA-IR ≥ 2.5 in comparison to those with HOMA-IR < 2.5. AUC triglycerides during OGTT is independently related to body composition, b-cell function and insulin sensitivity; and AUC triglycerides during MMTT is independently related to blood pressure and hsCRP in prediabetes. Triglycerides/HDL-C ratio emerged as an independent contributor to glycaemia and insulinemia., Conclusion: Our results demonstrate a similar lipid profile in subjects with 1hrOGTT > 8.6 mmol/l and IGT, whereas increased AUC triglycerides during OGTT, AUC triglycerides during MMTT and triglycerides/HDL-C ratio have been found in the subgroups with insulin resistance. The triglycerides/HDL-C ratio outlined as an independent predictor of insulin secretion and action, and postload triglycerides appear to be independently related to most of the metabolic parameters., Competing Interests: Declaration of competing interest There are no potential conflicts of interest relevant to this article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Aims: To examine the association of daily PA levels and sedentary behaviour with body composition, estimated insulin sensitivity, and arterial stiffness in adults with type 1 diabetes (T1D)., Methods: Cross-sectional study in adults with T1D (n = 54). PA levels (daily steps, and time in moderate-to-vigorous intensity PA (MVPA)) and sedentary behaviour were measured using accelerometry for 7 days (McRoberts® DynaPort MoveMonitor). Cardiopulmonary exercise test for VO 2max . Anthropometrics were collected, and body composition (total and % of fat mass (FM tot , FM % ), total and % of lean mass (LM tot , LM % ), and estimated visceral adipose tissue (VAT)) volume was assessed with dual energy X-ray-absorptiometry (DXA). Estimates of insulin sensitivity were determined (estimated glucose disposal rate (eGDR) and total daily insulin dose). Arterial stiffness was assessed with carotid-femoral pulse wave velocity (cf-PWV (m/s); SphygmoCor®)., Results: Lower 10-years HbA1 c associated moderately with all PA measures. Favourable moderate associations were also found between PA measures and BMI, waist, VAT but not FM and LM. PA measures were favourably associated with a lower total daily insulin dose and higher eGDR. All PA parameters associated moderately with cf-PWV however not independent from traditional risk factors. VO 2max was inversely associated with cf-PWV independent of age, T1D duration and 24-hour mean blood pressure., Conclusions: Higher levels of PA, lower sedentary behaviour and greater exercise capacity are favourably associated with long-term glycaemic control, body composition, insulin dosage, estimated insulin sensitivity and arterial stiffness in adults with T1D. Therefore, regular PA and limiting sedentary time should be encouraged to improve metabolic and cardiovascular health in this population. Future longitudinal studies should explore mutual interactions and synergistic effects of PA on these outcomes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Aims: The International Diabetes Federation (IDF) has recently recommended determination of 1-hour plasma glucose (1-hPG) during an oral glucose tolerance test (OGTT) to diagnose intermediate hyperglycemia (IH) and type 2 diabetes (T2DM). Herein, we investigated the cardiometabolic characteristics of individuals with IH and T2DM according to IDF criteria., Methods: We studied 3086 individuals stratified on the basis of fasting, 1-hPG and 2-hPG in four groups: 1) normal glucose tolerance (NGT), 2) isolated impaired fasting glucose (iIFG,), 3) IH (fasting glucose < 126 mg/dL, 1-hPG 155-208 mg/dL, and/or 2-hPG 140-199 mg/dL, and 4) newly diagnosed T2DM (fasting glucose, 1-hPG and/or 2-hPG≥126 mg/dL, 209 mg/dL and 200 mg/dL, respectively)., Results: Individuals with IH and T2DM exhibited higher adiposity, blood pressure, uric acid, a worse lipid and inflammatory profile and a progressive reduction in Matsuda index of insulin sensitivity, insulinogenic index, and disposition index as compared to the NGT group. Moreover, individuals with IH and T2DM exhibited lower Matsuda, insulinogenic, and disposition indexes as compared to the iIFG group., Conclusions: 1-h PG-based criteria for diagnosis of IH and diabetes identify individuals having an unfavorable cardiometabolic risk profile with a progressive reduction in insulin sensitivity associated with impaired β cell function., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Insulin resistance, defined as an impaired biological response to insulin stimulation in target tissues, arises most frequently in the presence of central obesity. Although obesity is generally associated with increased bone mass, recent data challenge this view and, if complicated by T2DM, obese patients are at high risk for fragility fractures. IR may play a key role in this increased fracture risk through effects on bone quality rather than bone quantity. Further understanding of the mechanisms and approaches to prevent osteoporotic fractures in IR-related diseases is needed., Clinical Relevance: The dramatic increase in obesity and metabolic syndrome (MetS) over the last half-century has led to a worldwide epidemic of type 2 diabetes mellitus (T2DM) as well as in the incidence of insulin resistance (IR). IR is defined as an impaired biological response to insulin stimulation in target tissues and is primarily related to the liver, muscle, and adipose tissue. The most frequent underlying cause is central obesity, and it is known that excess abdominal adipose tissue secretes increased amounts of free fatty acids, which directly affects insulin signalling, reduces glucose uptake in muscle, and triggers excessive triglyceride synthesis and gluconeogenesis in the liver. When pancreatic β cells are unable to secrete the higher levels of insulin needed, T2DM, the main complication of IR, occurs., Observations: Although obesity is generally associated with increased bone mass, recent data challenge this view and highlight the multifaceted nature of the obesity-bone relationship. Patients with T2DM are at significant risk for well-known complications of diabetes, including retinopathy, nephropathy, macrovascular disease, and neuropathy, but it is clear that they are also at high risk for fragility fractures. Moreover, recent data provide strong evidence that IR may key role in the increased fracture risk observed in both obesity and T2DM., Conclusions: In this concise review article, the role of IR in increased risk of osteoporotic fractures in MetS, obesity, and T2DM is discussed and summarised, including consideration of the need for fracture risk assessment as a 'preventive measure', especially in patients with T2DM and chronic MetS with abdominal obesity. Personalised and targeted diagnostic and therapeutic approaches to prevent osteoporotic fractures in IR-related diseases are needed and could make significant contributions to health outcomes., (© 2024. International Osteoporosis Foundation and Bone Health and Osteoporosis Foundation.)

The aim of this study was to examine the moderating role of cardiorespiratory fitness (CRF) between the relationship of cardiometabolic risk factors and adiponectin in adolescents. This is a cross-sectional study conducted with 255 adolescents of both sexes, aged 11 to 17 years. Anthropometric and biochemical parameters such as body mass, height, fat mass (FM), fat-free mass, high-density lipoprotein, low-density lipoprotein, triglycerides, glucose, insulin, adiponectin, systolic blood pressure, diastolic blood pressure, and peak oxygen consumption (VO2peak) were measured. Body mass index z-score (BMI-z), tri-ponderal mass index (TMI), homeostasis model assessment insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and age peak height velocity were calculated. The moderation analyses were tested using linear regression models. Interaction was observed with low CRF, indicating that those who achieved more than 2.27 (BMI-z), 2.18 (TMI), 2.10 (FM), 2.57 (insulin), 2.65 (HOMA-IR), and 2.81 (QUICKI) in L·min-1 on the CRF test may experience reduced risks in cardiometabolic risk factors., Conclusion: The deleterious effects attributed to excess adiposity and unfavorable changes related to insulin resistance and sensitivity may be attenuated by CRF., What Is Known: • Adiponectin, a protein derived from adipose tissue, may play a role as a potential marker of protection and predictor of cardiometabolic disorders and its relationship with cardiorespiratory fitness is controversial., What Is New: • The deleterious effects attributed to overweight and unfavorable changes related to insulin resistance and sensitivity may be attenuated by high cardiorespiratory fitness in adolescents., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Aims/hypothesis: Appropriate management of blood glucose levels and the prevention of complications are important in the treatment of diabetes. We have previously reported on a compound named HPH-15 that is not only antifibrotic but also AMP-activated protein kinase (AMPK)-activating. In this study, we evaluated whether HPH-15 is useful as a therapeutic medication for diabetes., Methods: We examined the effects of HPH-15 on AMPK activation, glucose uptake, fat accumulation and lactic acid production in L6-GLUT4, HepG2 and 3T3-L1 cells, as a model of muscle, liver and fat tissue, respectively. Additionally, we investigated the glucose-lowering, fat-accumulation-suppressing, antifibrotic and AMPK-activating effect of HPH-15 in mice fed a high-fat diet (HFD)., Results: HPH-15 at a concentration of 10 µmol/l increased AMPK activation, glucose uptake and membrane translocation of GLUT4 in each cell model to the same extent as metformin at 2 mmol/l. The production of lactic acid (which causes lactic acidosis) in HPH-15-treated cells was equal to or less than that observed in metformin-treated cells. In HFD-fed mice, HPH-15 lowered blood glucose from 11.1±0.3 mmol/l to 8.2±0.4 mmol/l (10 mg/kg) and 7.9±0.4 mmol/l (100 mg/kg) and improved insulin resistance. The HPH-15 (10 mg/kg) group showed the same level of AMPK activation as the metformin (300 mg/kg) group in all organs. The HPH-15-treated HFD-fed mice also showed suppression of fat accumulation and fibrosis in the liver and fat tissue; these effects were more significant than those obtained with metformin. Mice treated with high doses of HPH-15 also exhibited a 44% reduction in subcutaneous fat., Conclusions/interpretation: HPH-15 activated AMPK at lower concentrations than metformin in vitro and in vivo and improved blood glucose levels and insulin resistance in vivo. In addition, HPH-15 was more effective than metformin at ameliorating fatty liver and adipocyte hypertrophy in HFD-fed mice. HPH-15 could be effective in preventing fatty liver, a common complication in diabetic individuals. Additionally, in contrast to metformin, high doses of HPH-15 reduced subcutaneous fat in HFD-fed mice. Presumably, HPH-15 has a stronger inhibitory effect on fat accumulation and fibrosis than metformin, accounting for the reduction of subcutaneous fat. Therefore, HPH-15 is potentially a glucose-lowering medication that can lower blood glucose, inhibit fat accumulation and ameliorate liver fibrosis., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Non-alcoholic (now: metabolic) steatohepatitis (MASH) is the progressive inflammatory form of metabolic dysfunction-associated steatotic liver disease (MASLD), which often coexists and mutually interacts with type 2 diabetes (T2D), resulting in worse hepatic and cardiovascular outcomes. Understanding the intricate mechanisms of diabetes-related MASH progression is crucial for effective therapeutic strategies. This review delineates the multifaceted pathways involved in this interplay and explores potential therapeutic implications. The synergy between adipose tissue, gut microbiota, and hepatic alterations plays a pivotal role in disease progression. Adipose tissue dysfunction, particularly in the visceral depot, coupled with dysbiosis in the gut microbiota, exacerbates hepatic injury and insulin resistance. Hepatic lipid accumulation, oxidative stress, and endoplasmic reticulum stress further potentiate inflammation and fibrosis, contributing to disease severity. Dietary modification with weight reduction and exercise prove crucial in managing T2D-related MASH. Additionally, various well-known but also novel anti-hyperglycemic medications exhibit potential in reducing liver lipid content and, in some cases, improving MASH histology. Therapies targeting incretin receptors show promise in managing T2D-related MASH, while thyroid hormone receptor-β agonism has proven effective as a treatment of MASH and fibrosis., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: SG declares no competing interests. MR reports consulting fees and/or speaker’s fees from Astra Zeneca, Echosens, Eli Lilly, Madrigal, MSD, Novo Nordisk and Boehringer Ingelheim and is supported for investigator-initiated trials by Boehringer Ingelheim and Novo Nordisk. LC reports consulting fees from Boston pharmaceutical, Echosens, Gilead, GSK, Madrigal, MSD, Novo Nordisk, Pfizer, Sagimet and Siemens Healthineers and speaker fees from Echosens, Gilead, Inventiva, Madrigal and Novo Nordisk., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Polycystic ovary syndrome (PCOS) is a highly prevalent disorder in women that is commonly accompanied by metabolic syndrome. Activation of the hypoxia-inducible factor (HIF) pathway is known to alleviate metabolic defects. Hence, this study utilized a preclinical PCOS mouse model to investigate the effects of chemically induced HIF activation on the metabolic traits of PCOS. Prepubertal letrozole treatment was used to generate a PCOS mouse model in the C57Bl6/J strain, and PCOS mice were orally treated with vehicle or roxadustat for six weeks from age 12 weeks onwards to induce HIF activation. Although the PCOS mice showed impaired glucose tolerance, increased insulin resistance, elevated blood lipids, and reduced muscle glycogen content, there was no difference in histological evaluations of white adipose tissue (WAT) or liver or in organ weights. Roxadustat treatment resulted in significant improvement in glucose tolerance (27 % reduction in area under the curve (AUC) values, p < 0.0001), fasting glucose levels (4.59 ± 0.83 mmol/l vs 3.05 ± 0.62 mmol/l, p < 0.0001) and insulin resistance (46 % reduction in homeostasis model assessment-insulin resistance (HOMA-IR) values, 6.76 ± 3.72 vs 3.64 ± 2.44, p = 0.019) compared to vehicle-treated mice without altering the body weight. Gene expression analyses with real-time quantitative polymerase chain reaction (RT-qPCR) and RNA sequencing revealed significant differences in gene expression in the tissues of PCOS mice compared to control mice, whereas the transcriptomic effects of roxadustat were mainly transient. However, immunohistochemistry revealed increased uncoupling protein 1 (UCP1) expression in WAT, which may indicate WAT browning related to HIF pathway activation., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Terhi T. Piltonen reports financial support was provided by Novo Nordisk Foundation. Terhi T. Piltonen and Peppi Koivunen reports financial support was provided by Sigrid Jusélius Foundation. Peppi Koivunen reports financial support was provided by Jane and Aatos Erkko Fundation. Terhi T. Piltonen and Peppi Koivunen reports financial support was provided by Research Council of Finland. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Peripheral neuropathy (PN) is a prevalent and debilitating complication of obesity, prediabetes, and type 2 diabetes, which remains poorly understood and lacks disease-modifying therapies. Fortunately, diet and/or exercise have emerged as effective treatment strategies for PN. Here, we examined the impact of caloric restriction (CR) and high-intensity interval training (HIIT) interventions, alone or combined (HIIT-CR), on metabolic and PN outcomes in high-fat diet (HFD) mice. HFD feeding alone resulted in obesity, impaired glucose tolerance, and PN. Peripheral nerves isolated from these mice also developed insulin resistance (IR). CR and HIIT-CR, but not HIIT alone, improved HFD-induced metabolic dysfunction. However, all interventions improved PN to similar extents. When examining the underlying neuroprotective mechanisms in whole nerves, we found that CR and HIIT-CR activate the fuel-sensing enzyme AMPK. We then performed complimentary in vitro work in Schwann cells, the glia of peripheral nerves. Treating primary Schwann cells with the saturated fatty acid palmitate to mimic prediabetic conditions caused IR, which was reversed by the AMPK activator, AICAR. Together, these results enhance our understanding of PN pathogenesis, the differential mechanisms by which diet and exercise may improve PN, and Schwann cell-specific contributions to nerve insulin signaling and PN progression., (© 2024 by the American Diabetes Association.)

Aims/hypothesis: Clustering-based subclassification of type 2 diabetes, which reflects pathophysiology and genetic predisposition, is a promising approach for providing personalised and effective therapeutic strategies. Ahlqvist's classification is currently the most vigorously validated method because of its superior ability to predict diabetes complications but it does not have strong consistency over time and requires HOMA2 indices, which are not routinely available in clinical practice and standard cohort studies. We developed a machine learning (ML) model to classify individuals with type 2 diabetes into Ahlqvist's subtypes consistently over time., Methods: Cohort 1 dataset comprised 619 Japanese individuals with type 2 diabetes who were divided into training and test sets for ML models in a 7:3 ratio. Cohort 2 dataset, comprising 597 individuals with type 2 diabetes, was used for external validation. Participants were pre-labelled (T2D kmeans ) by unsupervised k-means clustering based on Ahlqvist's variables (age at diagnosis, BMI, HbA 1c , HOMA2-B and HOMA2-IR) to four subtypes: severe insulin-deficient diabetes (SIDD), severe insulin-resistant diabetes (SIRD), mild obesity-related diabetes (MOD) and mild age-related diabetes (MARD). We adopted 15 variables for a multiclass classification random forest (RF) algorithm to predict type 2 diabetes subtypes (T2D RF15 ). The proximity matrix computed by RF was visualised using a uniform manifold approximation and projection. Finally, we used a putative subset with missing insulin-related variables to test the predictive performance of the validation cohort, consistency of subtypes over time and prediction ability of diabetes complications., Results: T2D RF15 demonstrated a 94% accuracy for predicting T2D kmeans type 2 diabetes subtypes (AUCs ≥0.99 and F1 score [an indicator calculated by harmonic mean from precision and recall] ≥0.9) and retained the predictive performance in the external validation cohort (86.3%). T2D RF15 showed an accuracy of 82.9% for detecting T2D kmeans , also in a putative subset with missing insulin-related variables, when used with an imputation algorithm. In Kaplan-Meier analysis, the diabetes clusters of T2D RF15 demonstrated distinct accumulation risks of diabetic retinopathy in SIDD and that of chronic kidney disease in SIRD during a median observation period of 11.6 (4.5-18.3) years, similarly to the subtypes using T2D kmeans . The predictive accuracy was improved after excluding individuals with low predictive probability, who were categorised as an 'undecidable' cluster. T2D RF15 , after excluding undecidable individuals, showed higher consistency (100% for SIDD, 68.6% for SIRD, 94.4% for MOD and 97.9% for MARD) than T2D kmeans ., Conclusions/interpretation: The new ML model for predicting Ahlqvist's subtypes of type 2 diabetes has great potential for application in clinical practice and cohort studies because it can classify individuals with missing HOMA2 indices and predict glycaemic control, diabetic complications and treatment outcomes with long-term consistency by using readily available variables. Future studies are needed to assess whether our approach is applicable to research and/or clinical practice in multiethnic populations., (© 2024. The Author(s).)

Objective: Gestational diabetes mellitus (GDM) disrupts placental function and increases risks for pregnancy. This study investigates the potential involvement of AKT1 and MAPK8 genes, known for their roles in insulin resistance and cell signaling, in GDM pathophysiology. Methods: Placental tissues from GDM patients and healthy controls were analyzed using real-time PCR to quantify gene expression levels. In silico analysis further explored the functional implications of expression changes. Results: AKT1 and MAPK8 displayed significantly altered expression in GDM placentas compared to controls ( p  = 0.047 and p  = 0.007, respectively). In silico analysis suggests potential functional consequences related to diabetes-associated pathways. Conclusion: This study identifies differential expression of AKT1 and MAPK8 in GDM placentas, suggesting their potential roles in the disease process. Further investigation into their functional contributions could provide valuable insights into GDM pathophysiology and potential therapeutic targets.

Aims/hypothesis: The temporal suppression of insulin clearance after glucose ingestion is a key determinant of glucose tolerance for people without type 2 diabetes. Whether similar adaptations are observed after the ingestion of a mixed-macronutrient meal is unclear., Methods: In a secondary analysis of data derived from two randomised, controlled trials, we studied the temporal responses of insulin clearance after the ingestion of a standardised breakfast meal consisting of cereal and milk in lean normoglycaemic individuals (n=12; Lean-NGT), normoglycaemic individuals with central obesity (n=11; Obese-NGT) and in people with type 2 diabetes (n=19). Pre-hepatic insulin secretion rates were determined by the deconvolution of C-peptide, and insulin clearance was calculated using a single-pool model. Insulin sensitivity was measured by an oral minimal model., Results: There were divergent time course changes in insulin clearance between groups. In the Lean-NGT group, there was an immediate post-meal increase in insulin clearance compared with pre-meal values (p<0.05), whereas insulin clearance remained stable at baseline values in Obese-NGT or declined slightly in the type 2 diabetes group (p<0.05). The mean AUC for insulin clearance during the test was ~40% lower in the Obese-NGT (1.3 ± 0.4 l min -1 m -2 ) and type 2 diabetes (1.4 ± 0.7 l min -1 m -2 ) groups compared with Lean-NGT (1.9 ± 0.5 l min -1 m -2 ; p<0.01), with no difference between the Obese-NGT and type 2 diabetes groups. HOMA-IR and glucagon AUC emerged as predictors of insulin clearance AUC, independent of BMI, age or insulin sensitivity (adjusted R 2 =0.670). Individuals with increased glucagon AUC had a 40% reduction in insulin clearance AUC (~ -0.75 l min -1 m -2 ; p<0.001)., Conclusions/interpretation: The ingestion of a mixed-macronutrient meal augments differing temporal profiles in insulin clearance among individuals without type 2 diabetes, which is associated with HOMA-IR and the secretion of glucagon. Further research investigating the role of hepatic glucagon signalling in postprandial insulin kinetics is warranted., Trial Registration: ISRCTN17563146 and ISRCTN95281775., (© 2024. The Author(s).)

Introduction: Polycystic ovarian syndrome (PCOS) is the commonest endocrine condition affecting reproductive age women. Many biomarkers may aid assessment and management, however evidence is limited on their utility in clinical practice. We conducted a review of systematic reviews to identify the most useful biomarkers in the clinical management of PCOS., Methods: We searched MEDLINE, EMBASE, CENTRAL and HTA until August 2023 for reviews evaluating biomarkers in PCOS women compared to healthy controls. Methodological quality was assessed using the AMSTAR2 tool. We reported pooled evidence for each biomarker with 95% confidence intervals from the most recent, up-to-date, and best quality review., Results: From 3360 citations, we included 75 systematic reviews (88 biomarkers, 191,792 women). Most reviews (50/75, 67%) were moderate quality, but reported high heterogeneity (66/75, 88%). We identified 63 abnormal biomarkers in women with PCOS versus healthy controls. Of these, 22 core biomarkers could help evaluate the multisystemic impact of PCOS and inform patient management and surveillance: dehydroepiandrosterone, prolactin, sex hormone-binding globulin, total and free testosterone, anti-Mullerian hormone, systolic and diastolic blood pressure, c-reactive protein, fibrinogen, oral glucose tolerance test, homoeostatic model assessment-insulin resistance index, fasting insulin, total cholesterol, triglycerides, lipoprotein(a), HDL, LDL, non-HDL-cholesterol, ferritin, iron, and 25-hydroxy-vitamin D., Conclusion: We identified 22 core biomarkers assessing the multisystemic impact of PCOS and inform its clinical management. Future research is required to establish validated healthcare pathways., (© 2024 The Author(s). Clinical Endocrinology published by John Wiley & Sons Ltd.)

The translocon-associated protein-δ (TRAPδ) plays a role in insulin biosynthesis within pancreatic β-cells. However, its pathophysiological significance in maintaining islet β-cell function and glucose homeostasis remains unclear. In this study, we generated a mouse model featuring pancreatic β-cell-specific deletion of TRAPδ (TRAPδ βKO). Our findings revealed that TRAPδ βKO resulted in decreased circulating insulin levels in mice fed either a normal chow diet or a high-fat diet. Multiple independent experiments established that although TRAPδ deletion reduced insulin content in the islets, it had no discernible effect on insulin gene expression, the insulin to proinsulin ratio, or the expression and glycosylation of the prohormone enzymes involved in proinsulin processing. These data suggest that TRAPδ does not play a pivotal role in the transcription of the insulin gene or proinsulin processing. However, untranslocated preproinsulin levels were significantly increased when islets were treated with a proteasomal inhibitor, suggesting that TRAPδ deficiency may hinder preproinsulin translocation, resulting in a rapid degradation of untranslocated preproinsulin that accounts for the decreased insulin production. Remarkably, despite the moderate decrease in circulating insulin levels in TRAPδ βKO mice, their glucose levels remained unaffected, indicating the presence of compensatory mechanisms that help maintain glucose homeostasis. Insulin tolerance tests further revealed improved insulin sensitivity, accompanied by upregulation of phosphorylated AKT in the peripheral tissues of TRAPδ βKO mice. Collectively, these data highlight the important role of TRAPδ in insulin biosynthesis and β-cell function. The moderate reduction in circulating insulin appears to promote insulin sensitivity in insulin target tissues., (© 2024 by the American Diabetes Association.)

Importance: Research suggests that low-grade, nonresolving inflammation may predate adult mental and physical illness. However, evidence to date is largely cross-sectional or focuses on single disorder outcomes., Objectives: To examine trajectories of inflammation as measured by C-reactive protein (CRP) levels in a large sample of children and adolescents, and to explore associations between different identified trajectories and mental and related cardiometabolic health outcomes in early adulthood., Design, Setting, and Participants: In a longitudinal cohort study using data from the large UK-based Avon Longitudinal Study of Parents and Children (ALSPAC), latent class growth analysis (LCGA) was used to explore different trajectories of inflammation, with logistic regression exploring association with mental and physical health outcomes. Participants with measurable CRP data and associated mental and cardiometabolic health outcomes recorded were included in the analysis. Data analysis was performed from May 1, 2023, to March 30, 2024., Exposures: Inflammation was assessed via CRP levels at ages 9, 15, and 17 years. LCGA was used to identify different trajectories of inflammation., Main Outcomes and Measures: Outcomes assessed at age 24 years included psychotic disorders, depressive disorders, anxiety disorders, hypomania, and, as a measure of insulin resistance, Homeostasis Model Assessment (HOMA2) score., Results: A total of 6556 participants (3303 [50.4%] female) were included. Three classes of inflammation were identified: persistently low CRP levels (reference class, n = 6109); persistently raised CRP levels, peaking at age 9 years (early peak, n = 197); and persistently raised CRP levels, peaking at age 17 years (late peak, n = 250). Participants in the early peak group were associated with a higher risk of psychotic disorder (odds ratio [OR], 4.60; 95% CI, 1.81-11.70; P = .008), a higher risk of severe depression (OR, 4.37; 95% CI, 1.64-11.63; P = .02), and higher HOMA2 scores (β = 0.05; 95% CI, 0.01-0.62, P = .04) compared with participants with persistently low CRP. The late peak group was not associated with any outcomes at age 24 years., Conclusions and Relevance: Low-grade systemic inflammation peaking in midchildhood was associated with specific mental and cardiometabolic disorders in young adulthood. These findings suggest that low-grade persistent inflammation in early life may be an important shared common factor for mental-physical comorbidity and so could be relevant to future efforts of patient stratification and risk profiling.

Objectives: This study was designed to evaluate the association of four surrogate indexes of IR with NASH in patients with obesity., Methods: A total of 270 patients who underwent bariatric surgery, were included in this cross-sectional study. NASH was diagnosed based on liver biopsies. Binary logistics regression analyses were performed to assess the associations of four surrogate indexes of IR (HOMA-IR, Matsuda index, TyG, and TG/HDL-C) with NASH in patients with obesity. The restricted cubic spline was used to assess the dose-response associations of surrogate indexes of IR with NASH after adjusting for confounding factors., Results: NASH was diagnosed in 136 patients, with a prevalence of 50.37%. Compared with tertile 1, the fully adjusted ORs (95% CIs) of NASH for tertile 3 were 2.711(1.113-6.608) and 0.297 (0.152-0.579) for TyG and Matsuda index. Consistently, per SD increment of TyG were still significantly associated with 64% increased risks of NASH, and per SD increment of Matsuda index were still significantly associated with 38% decreased risks of NASH. In contrast, no significant associations were found between HOMA-IR and TG/HDL-C and the risk of NASH in patients with obesity (all P > 0.05). After adjusting covariates in restricted cubic splines, the risk of NASH decreased with the increment of Matsuda Index levels (P-nonlinear = 0.442, P-overall = 0.007) and with the decrement of TyG levels (P-nonlinear = 0.004, P-overall = 0.001)., Conclusions: In patients with obesity, TyG and Matsuda index were independently related to the risk of NASH after adjustment for traditional risk factors. In addition, compared with HOMA-IR and TG/HDL-C, the Matsuda index and TyG may be more suitable for NASH prediction in patients with obesity., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Nonalcoholic fatty liver disease (NAFLD), more appropriately known as metabolic (dysfunction) associated fatty liver disease (MAFLD), a prevalent condition in type 2 diabetes mellitus (T2DM) patients, is a complex condition involving hepatic lipid accumulation, inflammation, and liver fibrosis. The gut-liver axis is closely linked to metabolic dysfunction, insulin resistance, inflammation, and oxidative stress that are leading to the cooccurrence of MAFLD and T2DM cardiovascular diseases (CVDs). The purpose of this review is to raise awareness about the role of the gut-liver axis in the progression of MAFLD, T2DM and CVDs with a critical analysis of available treatment options for T2DM and MAFLD and their impact on cardiovascular health. This study analysed over 100 articles on this topic, using online searches and predefined keywords, to understand and summarise published research. Numerous studies have shown a strong correlation between gut dysfunction, particularly the gut microbiota and its metabolites, and the occurrence and progression of MAFLD and type 2 diabetes mellitus (T2DM). Herein, this article also examines the impact of the gut-liver axis on MAFLD, T2DM, and related complications, focusing on the role of gut microbiota dysbiosis in insulin resistance, T2DM and obesity-related cardiovascular complications. The study suggests potential treatment targets for MAFLD linked to T2DM, focusing on cardiovascular outcomes and the molecular mechanism of the gut-liver axis, as gut microbiota dysbiosis contributes to obesity-related metabolic abnormalities., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background & Aims: Metabolic dysfunction-associated steatohepatitis (MASH) is one of the most common liver diseases worldwide and is characterized by multi-tissue insulin resistance. The effects of a 10-month energy restriction and exercise intervention on liver histology, anthropometrics, plasma biochemistries, and insulin sensitivity were compared to standard of care (control) to understand mechanisms that support liver health improvements., Methods: Following medical diagnosis of MASH, individuals were randomized to treatment (n = 16) or control (n = 8). Liver fat (magnetic resonance spectroscopy), 18-hour plasma biochemical measurements, and isotopically labeled hyperinsulinemic-euglycemic clamps were completed pre- and post-intervention. Body composition and cardiorespiratory fitness (VO 2 peak) were also measured mid-intervention. Those in the treatment group were counseled to reduce energy intake and completed supervised, high-intensity interval training (3x/week) for 10 months. Controls continued physician-directed care., Results: Treatment induced significant (p <0.05) reductions in body weight, fat mass, and liver injury, while VO 2 peak (p <0.05) and non-esterified fatty acid suppression (p = 0.06) were improved. Both groups exhibited reductions in total energy intake, hemoglobin A1c, hepatic insulin resistance, and liver fat (p <0.05). Compared to control, treatment induced a two-fold increase in peripheral insulin sensitivity which was significantly related to higher VO 2 peak and resolution of liver disease., Conclusions: Exercise and energy restriction elicited significant and clinically meaningful treatment effects on liver health, potentially driven by a redistribution of excess nutrients to skeletal muscle, thereby reducing hepatic nutrient toxicity. Clinical guidelines should emphasize the addition of aerobic exercise in lifestyle treatments for the greatest histologic benefit in individuals with advanced MASH., Impact and Implications: The mechanisms that underpin histologic improvement in individuals with metabolic dysfunction-associated steatohepatitis (MASH) are not well understood. This study evaluated the relationship between liver and metabolic health, testing how changes in one may affect the other. We investigated the effects of energy restriction and exercise on the association between multi-tissue insulin sensitivity and histologic improvements in participants with biopsy-proven MASH. For the first time, these results show that an improvement in peripheral (but not hepatic) insulin sensitivity and systemic markers of muscle function (i.e. cardiorespiratory fitness) were strongly related to resolution of liver disease. Extrahepatic disposal of substrates and improved fitness levels supported histologic improvement, confirming the addition of exercise as crucial to lifestyle interventions in MASH., Clinical Trial Number: NCT03151798., (Copyright © 2024 European Association for the Study of the Liver. All rights reserved.)

Disentangling which of insulin hypersecretion and insulin resistance is upstream in obesity-related type 2 diabetes (T2D) is challenging. Here, we consider the dynamics of insulin secretion and action in the fetuses of mothers with diabetes. We argue that fetal insulin hypersecretion occurs first, with insulin resistance being an adaptive protective response., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective: Previous research points to a role of the brain in the regulation of glucose and pathogenesis of type 2 diabetes (T2D) via modulation of counter-regulatory hormone secretion and activity in the autonomic nervous system (ANS). The aim of this study was to investigate glucose-dependent responses of catecholamines and ANS activity in individuals with T2D, prediabetes (PD), and normoglycemia (NG)., Design: Cross-sectional., Methods: Individuals with T2D (n = 19, 7 men, HbA1c 49 mmol/mol), PD (n = 18, 8 men), and NG (n = 17, 3 men) underwent 1 stepwise hyperinsulinemic-euglycemic-hypoglycemic and 1 hyperglycemic clamp with repeated measurements of catecholamines, symptoms, heart rate variability (HRV), and hemodynamics., Results: The hypoglycemic response of adrenaline was augmented in T2D and PD vs NG (both P < .05), and there was a strong association with insulin resistance (P < .05 for M-value). In relation to achieved glucose levels in both clamps, noradrenaline exhibited a steeper rise during hypoglycemia in T2D vs NG and PD (both P < .05). There were trends toward more marked autonomic hypoglycemic symptoms in T2D vs PD and NG. By contrast, insulin resistance was associated with attenuated responses of heart rate and HRV indices PLF and PHF at the target glucose plateau of 2.7 mmol/L (P < .05), independent of BMI and HbA1c., Conclusion: Alterations in glucose-dependent responses of counter-regulatory hormones and the ANS appear before, and probably contribute to, the onset of T2D. Together with other reported alterations in neuroendocrine pathways, the findings suggest that a maladaptation of the brain's responses to glucose fluctuations is important in T2D progression., Competing Interests: Conflict of interest: The authors have no conflicts of interest to declare in relation to the current work., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Endocrinology.)

Adipose tissue holds a pivotal position in maintaining systemic energy homeostasis. Brown adipose tissue (BAT) expresses uncoupling protein 1 (UCP1), which is specialized in dissipating chemical energy as heat to maintain euthermia, a process called non-shivering thermogenesis. Conversely, white adipocyte (WAT) predominantly serves as the primary reservoir for energy storage, while also exhibiting endocrine activity by secreting various adipokines, thereby modulating systemic metabolism. Under the stimulation of cold exposure, physical activity and pharmacological intervention, WAT can occur as "browning" or "beiging", and transform into beige adipose tissue. The morphology and function of beige adipocyte are similar to brown adipocyte, both of which express higher levels of UCP1 and also have the function of thermogenesis. Thus, exploring methods to regulate the functional homeostasis of adipose tissue and its underlying molecular mechanisms hold promise for advancing preventative and therapeutic approaches against metabolic diseases. Exosomes, a subtype of extracellular vesicles (EVs) with a diameter of 40-100 nm, facilitate intercellular communication in obese individuals and exert significant influence on insulin resistance and impaired glucose tolerance within adipose tissue. These effects are primarily mediated by microRNA (miRNA) transported by exosomes. MiRNA, originating from various cellular sources, traverses between different cell types via EVs, thereby orchestrating reciprocal functional modulation among diverse tissues and organs. This review systematically summarized the research progress in exosomal miRNA-mediated regulation of adipose tissue functional homeostasis, with the aim of offering novel insights into the diagnosis and treatment of obesity and associated metabolic diseases.

Background: Mice experiments have underscored the efficacy of pharmacological inhibition of advanced glycation endproducts (AGEs) through the use of soluble receptors for advanced glycation endproducts (sRAGE) in mitigating obesity-linked metabolic disruptions and insulin resistance. However, human studies have presented conflicting findings regarding the correlation between circulating sRAGE levels and insulin resistance, as well as glucose tolerance. Here, we aimed to delve deeper into the relationship between sRAGE levels and systemic insulin sensitivity., Methods: Plasma sRAGE levels, hyperinsulinemic-euglycemic clamp, and continuous glucose monitoring were measured in two independent cross-sectional case-control studies [cohort 1 (n = 180) and cohort 2 (n = 124)]. In addition, a subgroup of 42 participants with obesity were followed for 12 months. In 14 of these participants, weight loss was achieved through bariatric surgery intervention., Results: Our results revealed a significant association between plasma sRAGE levels and both insulin sensitivity and glycemic control parameters, even after adjustments for age, sex, and BMI. Furthermore, longitudinal analysis demonstrated that interventions aimed at weight loss led to reductions in fasting glucose and HbA1c levels, concurrently with increases in sRAGE levels., Conclusions: These findings underscore that sRAGE levels were strongly associated with insulin sensitivity and glycemic control, suggesting a possible role of sRAGE in preserving insulin sensitivity and maintaining glycemic control, which should be confirmed in further studies., (© 2024. The Author(s).)

Background: Physical inactivity induces insulin resistance (IR) and metabolic imbalances before any significant changes in adiposity. Recent studies suggest that the beneficial effects of exercise can be potentiated if performed while fasting. This work aimed to compare the subacute effects of fed- and fasted-state single-bout exercise on biochemical parameters and cellular signaling in the metabolism. Methods: The animals were allocated into fed rest (FER), fasting rest (FAR), fed exercise (FEE), and fasting exercise (FAE) groups. The exercise protocol was a 30 min treadmill session at 60% of V˙O 2max . The fasting groups fasted for 8 h before exercise and were killed after 12 h post-exercise. Results: Soleus glycogen concentration increased only in the fasting groups, whereas the triglyceride (TGL) content increased in brown adipose tissue (BAT) and liver in the FAE. The FAE showed decreased plasma total cholesterol concentration compared withthe FAR group. Immunocontent of HSP70, SIRT1, UCP-1, and PGC1-α did not change in any tissue investigated. Conclusions: Our results indicate that physical exercise while fasting can have beneficial metabolic effects on sedentary animals. Remarkably, in the FAE group, there was a reduction in total plasma cholesterol and an increase in the capacity of BAT to metabolize and store nutrients in the form of TGLs.

Objective: Fasting insulin and the homeostasis model assessment of insulin resistance (HOMA-IR) index are relatively simple and reliable noninvasive markers of insulin resistance (IR). Given the relevance of correctly diagnosing IR, we emphasize the importance of establishing reliable reference intervals (RIs) for these markers. This study aimed to determine the RIs of fasting insulin and HOMA-IR index in adults living in Rio de Janeiro and, secondarily, to verify potential RI differences between sexes., Subjects and Methods: Serum insulin levels of 146,497 individuals (ages 20-60 years) who underwent blood sampling in the state of Rio de Janeiro were obtained retrospectively through access to an extensive laboratory database. Insulin was measured using the electrochemiluminescence immunoassay method. After applying exclusion criteria, 21,684 individuals (18,576 [86%] women) were included. The RIs were estimated using a computational mining approach that integrates a selection of R packages., Results: The 95% RIs in women and men and in the overall population were, respectively, 2.54-13.30 μU/mL (15.3-80.12 pmol/L), 2.43-11.89 μU/mL (14.6-71.7 pmol/L), and 2.52-13.14 μU/mL (15.2-79.2 pmol/L) for fasting insulin levels and 0.39-2.86, 0.38-2.81, and 0.39-2.86 for HOMA-IR values. Despite significant differences in insulin levels and HOMA-IR index between men and women, the use of sex-specific RIs was not justified., Conclusion: The RIs of fasting insulin levels and HOMA-IR values found in the overall population can be applied to both sexes. Thus, for our population, we suggest the RIs of 2.52-13.14 μU/mL (15.1-78.8 pmol/L) for fasting insulin and 0.39-2.86 for the HOMA-IR index., Competing Interests: Disclosure: no potential conflict of interest relevant to this article was reported.

The metabolic syndrome (MetS) is a multiplex modifiable risk factor for cardiovascular disease, type 2 diabetes mellitus and other health outcomes, and is a major challenge to clinical practice and public health. The rising global prevalence of MetS, driven by urbanization, sedentary lifestyles and dietary changes, underlines the urgency of addressing this syndrome. We explore the complex underlying mechanisms, including genetic predisposition, insulin resistance, accumulation of dysfunctional adipose tissue and ectopic lipids in abdominal obesity, systemic inflammation and dyslipidaemia, and how they contribute to the clinical manifestations of MetS. Diagnostic approaches vary but commonly focus on abdominal obesity (assessed using waist circumference), hyperglycaemia, dyslipidaemia and hypertension, highlighting the need for population-specific and phenotype-specific diagnostic strategies. Management of MetS prioritizes lifestyle modifications, such as healthy dietary patterns, physical activity and management of excess visceral and ectopic adiposity, as foundational interventions. We also discuss emerging therapies, including new pharmacological treatments and surgical options, providing a forward-looking perspective on MetS research and care. This Primer aims to inform clinicians, researchers and policymakers about MetS complexities, advocating for a cohesive, patient-centred management and prevention strategy. Emphasizing the multifactorial nature of MetS, this Primer calls for integrated public health efforts, personalized care and innovative research to address this escalating health issue., (© 2024. Springer Nature Limited.)

The mineralocorticoid system, comprising the renin-angiotensin-aldosterone system (RAAS) and associated receptors, is traditionally viewed as a regulator of sodium and fluid balance and blood pressure (BP), with the main mineralocorticoid hormone aldosterone acting via the mineralocorticoid receptor (MR) in distal renal tubules. Over the past few decades, there has been a wider understanding of the role of the mineralocorticoid system in regulating both classical BP-dependent and non-BP-dependent systemic effects. Mounting evidence indicates the novel role of the mineralocorticoid system in cardiometabolic health, with excess mineralocorticoid system activity being associated with adiposity, diabetes, insulin resistance and cardiovascular diseases independent of its effect on BP, and RAAS blockade and MR antagonists offering protection against cardiometabolic dysfunction. The metabolic manifestations of mineralocorticoid system overactivation are mainly mediated by their interactions with adipose tissue, which orchestrates energy, lipids, and glucose homeostasis via effects on the functions of brown and white adipocytes and immune cells. Adipose tissue can, in turn, influence mineralocorticoid system activity by harboring its own RAAS system and by releasing mineralocorticoid-secretory factors/adipokines, resulting in further progression of cardiometabolic dysfunction. This article discusses the interplay between the mineralocorticoid system and adipose tissue in the pathophysiology of cardiometabolic diseases.

Background: Chronic stress can induce the cognitive impairment, and even promote the occurrence and development of Alzheimer's disease (AD). Evidence has suggested that chronic stress impacts on glucose metabolism, and both of these have been implicated in AD. Here we focused on the effect of insulin resistance in glucose metabolism, and further evaluated the changes in cognition and pathology., Methods: Male 9-month-old wild-type and APP/PS1 mice were randomly divided into 4 groups. Mice in the chronic unpredictable mild stress (CUMS) groups were exposed for 4 weeks. Homeostatic Model Assessment (HOMA) was utilized to evaluate insulin sensitivity. A total of eighty-four genes related to the insulin signaling pathway were examined for rapid screening. Additionally, the phosphorylated protein expressions of insulin receptors (IR), IR substrate 1 (IRS1), c-Jun N-terminal kinase (JNK), and amyloid were detected in the hippocampus. Cognitive function was assessed through ethological methods. Cognitive function was assessed using both the Morris water maze (MWM) and the Passive avoidance test (PAT)., Results: Four weeks of CUMS exposure significantly increased the HOMA value, indicating reduced insulin sensitivity. The gene expressions of Insr and Lipe were downregulated. Additionally, the analysis revealed a significant interaction between the genotype (wild-type vs. APP/PS1) and CUMS treatment on the phosphorylated protein expressions of insulin receptor substrate 1 (IRS1). Specifically, CUMS exposure increased the inhibitory phosphorylation site (IRS1-pSer636) and decreased the excitatory phosphorylation site (IRS1-pTyr465) in the post-insulin receptor signaling pathway within the hippocampus of both wild-type and APP/PS1 mice. Moreover, CUMS exposure induced and exacerbated cognitive impairments in both wild-type and APP/PS1 mice, as assessed by the Morris water maze (MWM) and Passive avoidance test (PAT). However, there was no significant effect of CUMS on senile plaque deposition or levels of Aβ42 and Aβ40 in wild-type mice., Conclusions: Chronic stress significantly affects hippocampal cognitive function through insulin resistance and exacerbates AD pathology. This study reveals the complex relationship between chronic stress, insulin resistance, and AD, providing new insights for developing interventions targeting chronic stress and insulin resistance., Competing Interests: Declaration of Competing Interest The authors declare there is no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Heart failure (HF) is a condition caused by a malfunction of the heart's pumping function. The single-point insulin sensitivity estimator (SPISE) index is a novel indicator for assessing insulin resistance in humans. However, the connection between the SPISE index and the risk of HF in the elderly is unknown. Therefore, our study aims to evaluate the connection between the SPISE index and HF in older adults., Methods: The study was based on data collected from the 1999-2020 National Health and Nutrition Examination Survey database and included 6165 participants aged ≥60 years. The multivariable linear regression model and the smooth fitting curve model were applied to investigate the connection between the SPISE index and HF in the elderly. Furthermore, the subgroup analysis was performed to investigate the interactive factors., Results: In this study, the mean age of the population was 69.38 years. After adjusting for all covariates, we observed that the SPISE index was inversely related to the prevalence of HF (OR = 0.87, 95 % CI = 0.80-0.94, P < 0.001) in older adults. The interaction analysis showed that the association might be affected by diabetes mellitus and smoking status. Additionally, an inflection point between the SPISE index and HF was found among older women., Conclusions: An inverse correlation was detected between the SPISE index and HF in the elderly. This could provide new insight into the prevention and management of HF in the elderly population., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Addressing insulin resistance or hyperinsulinemia might offer a viable treatment approach to stop the onset of diabetic cardiomyopathy, as these conditions independently predispose to the development of the disease, which is initially characterized by diastolic abnormalities. The development of diabetic cardiomyopathy appears to be driven mainly by insulin resistance or impaired insulin signalling and/or hyperinsulinemia. Oxidative stress, hypertrophy, fibrosis, cardiac diastolic dysfunction, and, ultimately, systolic heart failure are the outcomes of these pathophysiological alterations. Melatonin is a ubiquitous indoleamine, a widely distributed compound secreted mainly by the pineal gland, and serves a variety of purposes in almost every living creature. Melatonin is found to play a leading role by improving myocardial cell metabolism, decreasing vascular endothelial cell death, reversing micro-circulation disorders, reducing myocardial fibrosis, decreasing oxidative and endoplasmic reticulum stress, regulating cell autophagy and apoptosis, and enhancing mitochondrial function. This review highlights a relationship between insulin resistance and associated cardiomyopathy. It explores the potential therapeutic strategies offered by the neurohormone melatonin, an important antioxidant that plays a leading role in maintaining glucose homeostasis by influencing the glucose transporters independently and through its receptors. The vast distribution of melatonin receptors in the body, including beta cells of pancreatic islets, asserts the role of this indole molecule in maintaining glucose homeostasis. Melatonin controls the production of GLUT4 and/or the phosphorylation process of the receptor for insulin and its intracellular substrates, activating the insulin-signalling pathway through its G-protein-coupled membrane receptors., Competing Interests: Declaration of competing interest Authors declare that they have no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The older segment of the global population is increasing at a rapid pace. Advancements in public health and modern medicine lengthened life expectancy and reduced the burden of disease in communities worldwide. Concurrent with this demographic change is the rise in overweight people and obesity, which is evident in all age groups. There is also an aging-related reduction in muscle mass and function, or sarcopenia, that is exacerbated by sedentary lifestyle and poor nutrition. The coexistence of muscle loss and elevated body mass index, termed "sarcopenic obesity", has particularly deleterious consequences in older individuals. Worsening insulin resistance and a proinflammatory state operate at the pathophysiologic level and lead to adverse health outcomes such as a proclivity to cardiovascular disease, type 2 diabetes, and even cognitive dysfunction. Although the concept of sarcopenic obesity as a disease construct is being increasingly recognized, a clearer understanding is warranted in order to define its components and health impact. Research is needed at the molecular-cellular level to tie together derangements in insulin action, cytokines, myokines, and endothelial dysfunction with clinical outcomes. Lifestyle modifications as well as targeted nonpharmacologic approaches, such as supplements and antioxidants, appear to have a promising role in reducing the chronic burden of this emerging disorder. Breakthroughs in drug therapies that retard or even reverse the underlying dynamics of sarcopenia and obesity in older persons are being actively explored.

Background: Postpartum depression (PPD) constitutes a significant mental health disorder affecting almost one fifth of pregnancies globally. Despite extensive research, the precise etiological mechanisms underlying PPD remain elusive. However, several risk factors like genetic predisposition, hormonal fluctuations, and stress-related environmental and psychosocial triggers have been found to be implicated in its development. MAIN: Recently, an increased risk of PPD has been reported to be associated with gestational diabetes mellitus (GDM), which is characterized by the disruption of glucose metabolism, primarily attributed to the emergence of insulin resistance (IR). While IR during pregnancy seems to be an evolutionary adaptative mechanism to handle the profound metabolic alterations during pregnancy, its subsequent resolution following delivery necessitates a reconfiguration of the metabolic landscape in both peripheral tissues and the central nervous system (CNS). Considering the pivotal roles of energy metabolism, particularly glucose metabolism, in CNS functions, we propose a novel model that such pronounced changes in IR and the associated glucose metabolism seen postpartum might account for PPD development. This concept is based on the profound influences from insulin and glucose metabolism on brain functions, potentially via modulating neurotransmitter actions of dopamine and serotonin. Their sudden postpartum disruption is likely to be linked to mood changes, as observed in PPD., Conclusions: The detailed pathogenesis of PPD might be multifactorial and still remains to be fully elucidated. Nevertheless, our hypothesis might account in part for an additional etiological factor to PPD development. If our concept is validated, it can provide guidance for future PPD prevention, diagnosis, and intervention., (© 2024. The Author(s).)

Background: The triglyceride-glucose (TyG) index is regarded as an independent predictor of cardiovascular disease consequences and a reliable surrogate measure of insulin resistance (IR). However, the correlation analysis between triglyceride glucose index and heart failure with preserved ejection fraction in patients with essential hypertension remains unknown., Methods: A single-center, retrospective study was conducted with patients diagnosed with essential hypertension at the First Affiliated Hospital of Xinjiang Medical University, from December 2018 to September 2020. Participants were selected based on specific inclusion and exclusion criteria, with their clinical data and laboratory tests collected. The study employed Spearman's correlation analysis, logistic regression models, restricted cubic spline plots, and receiver operating characteristic (ROC) curves to investigate the relationships between the TyG index and HFpEF., Results: Out of 1,602 enrolled hypertensive patients, 992 were included in the analysis after applying exclusion criteria. Patients were categorized into tertiles based on the TyG index, which showed that patients in the highest tertile had characteristics associated with a higher risk of HFpEF, including age, body mass index (BMI), systolic blood pressure (SBP), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and left ventricular mass index (LVMI). A significant, independent association between the TyG index and HFpEF was confirmed, with an odds ratio (OR) of 5.127 (95% CI [3.894-6.856]). Furthermore, an S-shaped nonlinear relationship was observed between the TyG index and the incidence of HFpEF (nonlinear p < 0.001). TyG index (AUC: 0.824, 95% CI [0.795-0.854]), NT-proBNP (AUC: 0.840, 95% CI [0.816-0.864]), and LVMI (AUC: 0.847, 95% CI [0.820-0.875]) showed good predictive ability for HFpEF. In addition, the TyG+LVMI combination demonstrated the strongest predictive ability (AUC: 0.907, 95% CI [0.887-0.927])., Conclusion: The study underscores a significant association between IR, as indicated by the TyG index, and the development of HFpEF in hypertensive patients. It highlights the critical role of metabolic dysfunction in the pathophysiology of HFpEF, advocating for a broader perspective on cardiovascular risk management., Competing Interests: The authors declare that they have no competing interests., (© 2024 Shan et al.)

Background: Stroke is a major cause of illness, death, and long-term disability and a major health concern worldwide. Experts consider insulin resistance (IR), a defining feature of the metabolic syndrome and a significant risk factor for stroke. Insulin resistance, or IR, is common among stroke patients. The triglyceride-glucose (TYG) index's relevance to both lipotoxicity and glucotoxicity has led to its proposal as an alternative indicator of IR., Aim: Examining the connection between elevated TYG INDEX scores and worse clinical outcomes in ischemic stroke patients is the main goal. Finding out how often bad outcomes (recurrence and all-cause death) are in ischemic stroke patients is the secondary goal., Method: This was a retrospective observational study that involved patients admitted to the 850-bed Dr. Pinnamaneni Siddhartha Institute of Medical Sciences and Research Foundation, a tertiary care teaching hospital located in the Krishna district of Andhra Pradesh (India). The study was conducted over a period of six months. All the 95 patients who satisfied the eligibility criteria were included. The patients' TYG INDEX values were first determined and patients with ischemic stroke who had elevated TYG INDEX values were then compared for clinical outcomes including recurrence and all-cause death with ischemic patients with normal TYG INDEX., Results: In this study, the total cholesterol of the patients (mean ± SD) was 165.01 ± 51.5 mg/dL; Triglycerides was 157.031 ± 98.9 mg/dL; HDL-c was 37.253 ± 5.52 mg/dl; LDL-c was 107 ± 48.3 mg/Dl; and FBS was 153.74 ± 71.52 mg/dL. The chi-square test showed that only FBS, Triglyceride, and Total cholesterol were significantly associated with TYG INDEX whereas other variables like age, LDL, and HDL were not. There was no significant association between the TYG INDEX and clinical outcomes of ischemic stroke. In both groups of patients, risk and no risk TYG INDEX values, the mRS score showed variable and unpredictable relationship with the TYG INDEX., Conclusion: Contrary to the few studies that discovered one, our research leads us to the conclusion that there may not be a relevant association between the TYG INDEX and clinical results in patients with ischemic stroke., (© 2024. The Author(s).)

Background: IL-2 regulates T cell differentiation: low-dose IL-2 induces immunoregulatory Treg differentiation, while high-dose IL-2 acts as a potent activator of cytotoxic T cells and NK cells. Therefore, high-dose IL-2 has been studied for use in cancer immunotherapy. We aimed to utilize low-dose IL-2 to treat inflammatory diseases such as obesity and insulin resistance, which involve low-grade chronic inflammation., Main Body: Systemic administration of low-dose IL-2 increased Treg cells and decreased inflammation in gonadal white adipose tissue (gWAT), leading to improved insulin sensitivity in high-fat diet-fed obese mice. Additionally, central administration of IL-2 significantly enhanced insulin sensitivity through the activation of the sympathetic nervous system. The sympathetic signaling induced by central IL-2 administration not only decreased interferon γ (IFNγ) + Th1 cells and the expression of pro-inflammatory cytokines, including Il-1β, Il-6, and Il-8, but also increased CD4 + CD25 + FoxP3 + Treg cells and Tgfβ expression in the gWAT of obese mice. These phenomena were accompanied by hypothalamic microgliosis and activation of pro-opiomelanocortin neurons. Furthermore, sympathetic denervation in gWAT reversed the enhanced insulin sensitivity and immune cell polarization induced by central IL-2 administration., Conclusion: Overall, we demonstrated that IL-2 improves insulin sensitivity through two mechanisms: direct action on CD4 + T cells and via the neuro-immune axis triggered by hypothalamic microgliosis., (© 2024. The Author(s).)

Purpose: The purpose of this study was to investigate the correlation between insulin and Fetuin-B (FETUB) and the influence of FETUB on insulin signaling pathway in diabetic retinopathy (DR)., Methods: Enzyme-linked immunosorbent assay (ELISA) was used to analyze FETUB and insulin levels in the serum and aqueous fluid of patients with DR and healthy controls. Quantitative PCR (q-PCR), Western blotting, and ELISA were used to examine FETUB expression in ARPE-19, BV2, and Müller cells under insulin stimulation. Co-immunoprecipitation was used to investigate the interaction of FETUB with insulin receptor-β (IRβ). Insulin resistance (IR)-BV2 and IR-Müller cells were treated with FETUB recombinant protein or FETUB short hairpin RNA (shRNA) to explore the influence of FETUB on insulin signaling pathway in DR. LY294002 (a PI3K pathway inhibitor) was used to determine whether FETUB affects glucose metabolism via the PI3K/Akt pathway., Results: In aqueous fluid, FETUB concentrations were positively correlated with insulin levels. FETUB expression increased in Müller and BV2 cells under insulin regulation, and FETUB interacted with IRβ in retinal cells and mice retina. The interaction between IRβ and FETUB increased in BV2 and Müller cells under high-glucose than in controls. Insulin signaling pathway activation was suppressed in FETUB recombinant protein-treated BV2 and Müller cells but increased in FETUB shRNA-transfected cells. FETUB shRNA could not reverse LY294002-mediated inhibition of glucose transporter-4 expression., Conclusions: Retinal cells are the source of insulin-regulated FETUB. The FETUB interacts with IRβ and affects insulin signaling pathway in BV2 and Müller cells. FETUB may aggravate IR in BV2 and Müller cells via the PI3K/Akt pathway.

Purpose: The objective of this study is to examine the alterations in subcortical brain volume and cortical thickness among individuals diagnosed with Type 2 diabetes mellitus (T2DM) through the application of morphometry techniques and, additionally, to investigate the potential association between these modifications and insulin resistance (IR)., Materials and Methods: The present cross-sectional study comprised a total of 121 participants (n = 48 with healthy controls [HCs] and n = 73 with T2DM) who were recruited and underwent a battery of cognitive testing and structural magnetic resonance imaging (MRI). FreeSurfer was used to process the MRI data. Analysis of covariance compared discrepancies in cortical thickness and subcortical brain volume between T2DM and HCs, adjusting for the potential confounding effects of gender, age, education, and body mass index (BMI). Exploratory partial correlations investigated links between IR and brain structure in T2DM participants., Results: Compared with HCs, individuals with T2DM demonstrated a cortical thickness decrease in the right caudal middle frontal gyrus, right pars opercularis, left precentral gyrus, and bilateral superior frontal gyrus. Furthermore, this study for T2DM found that the severity of IR was inversely related to the volume of the left putamen and left hippocampus, as well as the thickness of the left pars orbitalis, left pericalcarine, right entorhinal area, and right rostral anterior cingulate gyrus., Conclusion: The evidence for structural brain changes in T2DM was observed, and alterations in cortical thickness were concentrated in the frontal lobes. Correlations between IR and frontal cortical thinning may serve as a potential neuroimaging marker of T2DM and lead to various diabetes-related brain complications., (© 2024 The Author(s). Brain and Behavior published by Wiley Periodicals LLC.)

Diabetes has arisen as a noteworthy global health issue, marked by escalating incidence and mortality rates. Insulin, crucial for preserving euglycemia, acts as a vital energy provider for various tissues. Iron metabolism notably plays a significant role in the development of insulin resistance, a key factor in the onset of various metabolic disorders. The intricate interaction between iron and insulin signaling encompasses complex regulatory mechanisms at the molecular level, thereby impacting cellular reactions to insulin. The intricate interplay between insulin and glucagon, essential for precise regulation of hepatic glucose production and systemic glucose levels, may be influenced by certain microelements for instance zinc, copper, iron, boron, calcium, cobalt, chromium, iodine, magnesium and selenium. While significant progress has been achieved in elucidating the pathophysiological connections between iron overload and glucose metabolism, our understanding of the involvement of the Fenton reaction and oxidative stress in insulin resistance influencing many chronical conditions remains limited. Furthermore, the exploration of the multifaceted roles of insulin in the human body continues to be a subject of active investigation by numerous scientific researchers. This review comprehensively outlines the potential adverse impact of iron overload on insulin function and glucose metabolism. Additionally, we provide a synthesis of findings derived from various research domains, encompassing population studies, animal models, and clinical investigations, to scrutinize the multifaceted relationship between iron and insulin sensitivity. Moreover, we delineate instances of correlations between serum iron levels and various medical conditions, including the diabetes also gestational diabetes and obesity., (© 2024. The Author(s).)