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Abstract Background The molecular mechanisms underlying nonalcoholic fatty liver disease (NAFLD) remain to be fully elucidated. Ubiquitin specific protease 13 (USP13) is a critical participant in inflammation-related signaling pathways, which are linked to NAFLD. Herein, the roles of USP13 in NAFLD and the underlying mechanisms were investigated. Methods L02 cells and mouse primary hepatocytes were subjected to free fatty acid (FFA) to establish an in vitro model reflective of NAFLD. To prepare in vivo model of NAFLD, mice fed a high-fat diet (HFD) for 16 weeks and leptin-deficient (ob/ob) mice were used. USP13 overexpression and knockout (KO) strategies were employed to study the function of USP13 in NAFLD in mice. Results The expression of USP13 was markedly decreased in both in vitro and in vivo models of NAFLD. USP13 overexpression evidently inhibited lipid accumulation and inflammation in FFA-treated L02 cells in vitro. Consistently, the in vivo experiments showed that USP13 overexpression ameliorated hepatic steatosis and metabolic disorders in HFD-fed mice, while its deficiency led to contrary outcomes. Additionally, inflammation was similarly attenuated by USP13 overexpression and aggravated by its deficiency in HFD-fed mice. Notably, overexpressing of USP13 also markedly alleviated hepatic steatosis and inflammation in ob/ob mice. Mechanistically, USP13 bound to transforming growth factor β-activated kinase 1 (TAK1) and inhibited K63 ubiquitination and phosphorylation of TAK1, thereby dampening downstream inflammatory pathways and promoting insulin signaling pathways. Inhibition of TAK1 activation reversed the exacerbation of NAFLD caused by USP13 deficiency in mice. Conclusions Our findings indicate the protective role of USP13 in NAFLD progression through its interaction with TAK1 and inhibition the ubiquitination and phosphorylation of TAK1. Targeting the USP13-TAK1 axis emerges as a promising therapeutic strategy for NAFLD treatment.

ObjectiveHypoglycemia represents a serious acute complication in individuals with type 1 diabetes mellitus (T1DM). In order to more effectively identify and discriminate the occurrence of hypoglycemic events in patients with T1DM, this study aims to evaluate the impact of two distinct glucose monitoring systems—Flash Glucose Monitoring (FGM) and Continuous Glucose Monitoring (CGM)—on the management of blood glucose levels and the emotional responses associated with hypoglycemic episodes in individuals with T1DM.MethodIn this study, a total of 113 patients with type 1 diabetes mellitus were enrolled and allocated to two groups for the implementation of Glucose Monitoring Systems (GMS). The groups consisted of the FreeStyle Libre group (FGM, n=56) and the ipro2 group (CGM, n=57). Participants in both groups utilized GMS at least biannually and completed a set of three questionnaires: the Diabetes Monitoring and Treatment Satisfaction Questionnaire (DMTSQ), the Diabetes Specific Quality of Life (DQOL), and the Chinese Version of the Hypoglycemia Fear Survey II (CFHSII). Clinical data, CGM metrics, and questionnaire scores were collected at the initial visit and after a one-year follow-up period.ResultsThe glucose coefficient of variation (GCV) and the standard deviation of blood glucose (SDBG) were independently associated with Time Below Range (TBR). Specifically, GCV could predict TBR ≥12%, with a cut-off point of 40.55. This yielded a specificity of 88.10% and a sensitivity of 68.18% in the overall patient population. For the FreeStyle Libre group and the iPro2 group, the cut-off points were 38.69 and 40.55, respectively, with specificities of 0.74 and 0.92, and sensitivities of 0.73 and 0.86, respectively. In the FreeStyle Libre group, where the frequency of use was greater than or equal to five times per year, the hypoglycemic episodes (time/month) and CHFSII-B scores were significantly reduced at follow-up compared to baseline (7.80 ± 10.25 vs 13.95 ± 14.87; 27.37 ± 11.05 vs 38.90 ± 21.61, respectively, all P 12%). The optimal cut-off point for GCV was determined to be 40.55.

ObjectiveThe purpose of this study was to determine the relation between the lipid accumulation product index (LAPI) and diabetic kidney disease (DKD) in patients with type 2 diabetes mellitus (T2DM).MethodsHerein, 931 patients were enrolled and their data were collected. Then the interrelation between LAPI and DKD was assessed using multivariate logistic regression analyses (LRAs) and by a restricted cubic spline (RCS).ResultsIn total, 931 participants (352 females and 579 males) aged 55 years on average were included in the study. After adjusting for several confounders, the odds ratio for DKD was increased evidently in the third LAPI tertile compared with that in the first LAPI tertile. In addition, the RCS revealed a positive interrelation between LAPI and DKD. In the subgroup analyses, age, sex, hyperlipidemia, hypertension, and HbA1c did not significantly interact with LAPI.ConclusionsLAPI was higher in the DKD group than in the no-DKD group, and LAPI is positively linked with DKD, which may have potential value to diagnose DKD in clinical practice.

Abstract Background Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. The fat mass and obesity–associated protein (FTO) has been shown to be involved in obesity; however, its role in NAFLD and the underlying molecular mechanisms remain largely unknown. Methods FTO expression was first examined in the livers of patients with NAFLD and animal and cellular models of NAFLD by real-time PCR and Western blotting. Next, its role in lipid accumulation in hepatocytes was assessed both in vitro and in vivo via gene overexpression and knockdown studies. Results FTO expression was obviously elevated in the livers of mice and humans with hepatic steatosis, probably due to its decreased ubiquitination. FTO overexpression in HepG2 cells induced triglyceride accumulation, whereas FTO knockdown exerted an opposing effect. Consistent with the findings of in vitro studies, adeno-associated viruses 8 (AAV8)-mediated FTO overexpression in the liver promoted hepatic steatosis in C57BL/6J mice. Mechanistically, FTO inhibited the mRNA of peroxisome proliferator-activated receptor α (PPARα) in hepatocytes. Activation of PPARα by its agonist GW7647 reversed lipid accumulation in hepatocytes induced by FTO overexpression. Conclusions Overall, FTO expression is increased in NAFLD, and it promotes hepatic steatosis by targeting PPARα.

Abstract Aims/Introduction Non‐alcoholic fatty liver disease, especially with liver fibrosis, is associated with cardiovascular diseases. The Non‐Alcoholic Fatty Liver Disease Fibrosis Score (NFS), a non‐invasive marker of advanced fibrosis, was found to be associated with cardiovascular diseases in different populations. The aim of the present study was to determine whether the NFS is associated with subclinical myocardial remodeling in type 2 diabetes patients. Materials and Methods A cross‐sectional study was carried out in type 2 diabetes patients. The NFS derived from available parameters was calculated, and the participants were divided according to the quartiles of the NFS and grades of the NFS (low, intermediate and high). Fibrosis‐4 and Aspartate Aminotransferase to Platelet Ratio Index, another two liver fibrosis scores, were also calculated. Subclinical myocardial remodeling was examined by echocardiography, and its associations with NFS, Fibrosis‐4 and Aspartate Aminotransferase to Platelet Ratio Index were analyzed. Results A total of 1,878 type 2 diabetes patients were enrolled in the present study. The NFS was independently associated with sex, age, body mass index, low‐density lipoprotein cholesterol and glycated hemoglobin in type 2 diabetes patients. Parameters of subclinical myocardial remodeling including left atrial dimension, interventricular septum thickness, left ventricular end‐diastolic diameter, left ventricular end‐systolic diameter, left ventricular posterior wall thickness (LVPWT) and left ventricular mass index were all gradually increased with the increment of the NFS. Linear regression analysis further showed that the NFS was positively associated with left atrial dimension, interventricular septum thickness, left ventricular end‐diastolic diameter, left ventricular end‐systolic diameter, LVPWT and left ventricular mass index after adjustment for the confounding factors. Similarly, Fibrosis‐4 was associated with left atrial dimension, interventricular septum thickness, LVPWT and left ventricular mass index. In contrast, the Aspartate Aminotransferase to Platelet Ratio Index was only associated with LVPWT. Conclusions Non‐invasive liver fibrosis scores, especially the NFS, are independently associated with subclinical myocardial remodeling in type 2 diabetes patients.

ObjectivePatients with type 2 diabetes have a high risk of non-alcoholic fatty liver disease (NAFLD) and related liver fibrosis. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have demonstrated efficacy in improving NAFLD, while their effectiveness on liver fibrosis is limited in type 2 diabetic patients.Materials/MethodsA prospective cohort study was performed in type 2 diabetic patients. The study subjects were divided into two groups based on the use of liraglutide or not, and propensity score matching (PSM) was also conducted. After 12 months follow-up, liver fibrosis was assessed by NAFLD fibrosis score (NFS) fibrosis-4 (FIB-4), and liver stiffness measurement (LSM). The association between liraglutide use and liver fibrosis was analyzed by multivariable linear regression.ResultsIn the current study, a total of 1,765 type 2 diabetic patients were enrolled. 262 patients were liraglutide user and 1,503 were nouser. After 12 months follow-up, liraglutide use tended to be associated with reduced prevalence of advanced fibrosis (3.1% vs. 6.1%, P = 0.218). After adjustment for confounding factors, multivariable linear regression revealed that liraglutide use was negatively associated with decreased NFS (β= -0.34, P = 0.043), FIB4 (β= -0.26, P = 0.044) and LSM (β= -4.95, P = 0.007) in type 2 diabetics. The results after PSM were similar to those before PSM.ConclusionsLiraglutide treatment is associated with decreased liver fibrosis in type 2 diabetic subjects.

Abstract Background Triglycerides (TG) to high-density lipoprotein cholesterol (HDL-C) ratio (TG/HDL-C) has been recommended as a surrogate marker for insulin resistance. In the present study, we aimed to investigate the relationship between TG/HDL-C and NAFLD in an apparently healthy population. Methods A total of 18,061 subjects who participated in a health checkup program were included. NAFLD was diagnosed by ultrasonography. Results The prevalence rate of NAFLD was 24.8% in the whole population, and progressively increased across the quartiles of TG/HDL-C (4.9, 14.1, 26.8 and 53.5%, respectively, P

Abstract Background The increasing prevalence of non-alcoholic fatty liver disease (NAFLD) has followed the international rise in obesity rates. Multiple mechanisms are involved in NAFLD, including endoplasmic reticulum stress and oxidative stress. Heat shock protein 70 (HSP70), which is abundant in most organisms, is sensitive to stress. However, the role of HSP70 in NAFLD has not been investigated. Here, we investigated the possible role of HSP70 in lipid synthesis. Methods C57BL/6 mice were fed a high-fat diet, and HepG2 cells were treated with 0.5 mM palmitic acid (PA). HSP70 expression was detected by qPCR, Western blot and immunohistochemistry. Total cholesterol (TC) and triglyceride (TG) levels were detected by enzyme-linked immunosorbent assay (ELISA). After Hsp70 overexpression and knockdown, TC and TG levels and FAS, SCD, and ACC expression were detected. Results HSP70 expression was significantly increased in the livers of obese mice. In vitro, HSP70 expression was markedly induced by PA in HepG2 cells. Notably, HSP70 overexpression in HepG2 cells enhanced TC and TG synthesis, in parallel with the upregulation of lipogenic genes, including FAS, SCD and ACC. By contrast, HSP70 knockdown decreased the levels of cellular lipids and the expression of FAS, SCD, and ACC in HepG2 cells. Together, our results suggest that HSP70 may promote lipogenesis in HepG2 cells. Conclusions Heat shock protein 70 promotes lipogenesis in HepG2 cells.

Background and Aim:Helicobacter pylori infection has been reported to promote the development of a variety of extra-digestive manifestations, including type 2 diabetes, cardiovascular and liver diseases. Recently, the association between H. pylori infection and non-alcoholic fatty liver disease (NAFLD) was also proposed. However, evidence from different studies was controversial. We therefore performed this study to investigate the relationship between them in a large population of apparently healthy subjects in China.Methods: A total of 21,456 subjects underwent a healthy checkup program were included. H. pylori infection was detected by 14C urea breath test (14C-UBT) and NAFLD was diagnosed by ultrasonography.Results: Subjects infected with H. pylori had a more unfavorable metabolic profile, including higher levels of body mass index (BMI), blood pressure, triglycerides (TG) and lower levels of high-density lipoprotein cholesterol (HDL-C), as compared with those without H. pylori infection (all P < 0.05). Moreover, the prevalence rate of NAFLD was significantly increased in subjects with H. pylori infection when compared with those without H. pylori in women (23.6% vs. 21.5%, P < 0.05), but not in men (46.5% vs. 45.5%, P > 0.05). After adjusting for confounding factors including age, sex, BMI, blood pressure and lipid profiles, multivariate logistic analysis revealed that H. pylori infection was not independently associated with the risk of NAFLD in the total population (OR = 0.9, 95% CI = 0.9–1.0, P = 0.097). Also, subgroup analysis (stratified by age, sex, BMI, and diabetes status) showed no independent association between H. pylori infection and NAFLD.Conclusion: Our data suggests that H. pylori infection is not independently associated with the risk of NAFLD in apparently healthy subjects.

Across-sectional study was performed in 541 type 2 diabetic patients to determine the relationship between serum uric acid (SUA) and NAFLD in type 2 diabetic patients. Clinical parameters including SUA were determined and NAFLD was diagnosed by ultrasonography. SUA was significantly higher in type 2 diabetic subjects with NAFLD than in those without NAFLD in men, but not in women. Furthermore, the prevalence rate of NAFLD increased progressively across the sex-specific SUA tertiles only in men (37.9%, 58.6%, and 72.6%, resp., P for trend < 0.001). After adjusting for confounding factors, the odd ratios (95% CI) for NAFLD were 1 (reference), 2.93 (95%CI 1.25–6.88), and 3.93 (95% CI 1.55–9.98), respectively, across the tertiles of SUA in men. Contrastingly, SUA levels in women were not independently associated with the risk of NAFLD. Our data suggests that SUA is specifically associated with NAFLD in male type 2 diabetic subjects, independent of insulin resistance and other metabolic factors.

Obesity-induced endoplasmic reticulum (ER) stress and inflammation lead to adipocytes dysfunction. Autophagy helps to adapt to cellular stress and involves in regulating innate inflammatory response. In present study, we examined the activity of rapamycin, a mTOR kinase inhibitor, against endoplasmic reticulum stress and inflammation in adipocytes. An in vitro model was used in which 3T3-L1 adipocytes were preloaded with palmitate (PA) to generate artificial hypertrophy mature adipocytes. Elevated autophagy flux and increased number of autophagosomes were observed in response to PA and rapamycin treatment. Rapamycin attenuated PA-induced PERK and IRE1-associated UPR pathways, evidenced by decreased protein levels of eIF2α phosphorylation, ATF4, CHOP, and JNK phosphorylation. Inhibiting autophagy with chloroquine (CQ) exacerbated these ER stress markers, indicating the role of autophagy in ameliorating ER stress. In addition, cotreatment of CQ abolished the anti-ER stress effects of rapamycin, which confirms the effect of rapamycin on ERs is autophagy-dependent. Furthermore, rapamycin decreased PA-induced nuclear translocation of NFκB P65 subunit, thereby NFκB-dependent inflammatory cytokines MCP-1 and IL-6 expression and secretion. In conclusion, rapamycin attenuated PA-induced ER stress/NFκB pathways to counterbalance adipocytes stress and inflammation. The beneficial of rapamycin in this context partly depends on autophagy. Stimulating autophagy may become a way to attenuate adipocytes dysfunction.

Obesity is associated with increased production of inflammatory mediators in adipose tissue, which contributes to chronic inflammation and insulin resistance. Midkine (MK) is a heparin-binding growth factor with potent proinflammatory activities. We aimed to test whether MK is associated with obesity and has a role in insulin resistance. It was found that MK was expressed in adipocytes and regulated by inflammatory modulators (TNF-α and rosiglitazone). In addition, a significant increase in MK levels was observed in adipose tissue of obese ob/ob mice as well as in serum of overweight/obese subjects when compared with their respective controls. In vitro studies further revealed that MK impaired insulin signaling in 3T3-L1 adipocytes, as indicated by reduced phosphorylation of Akt and IRS-1 and decreased translocation of glucose transporter 4 (GLUT4) to the plasma membrane in response to insulin stimulation. Moreover, MK activated the STAT3-suppressor of cytokine signaling 3 (SOCS3) pathway in adipocytes. Thus, MK is a novel adipocyte-secreted factor associated with obesity and inhibition of insulin signaling in adipocytes. It may provide a potential link between obesity and insulin resistance.

Obesity is associated with a state of chronic low-grade inflammation, which contributes to insulin resistance and type 2 diabetes. However, the molecular mechanisms that link obesity to inflammation are not fully understood. Follistatin-like 1 (FSTL1) is a novel proinflammatory cytokine that is expressed in adipose tissue and secreted by preadipocytes/adipocytes. We aimed to test whether FSTL1 could have a role in obesity-induced inflammation and insulin resistance. It was found that FSTL1 expression was markedly decreased during differentiation of 3T3-L1 preadipocytes but reinduced by TNF-α. Furthermore, a significant increase in FSTL1 levels was observed in adipose tissue of obese ob/ob mice, as well as in serum of overweight/obese subjects. Mechanistic studies revealed that FSTL1 induced inflammatory responses in both 3T3-L1 adipocytes and RAW264.7 macrophages. The expression of proinflammatory mediators including IL-6, TNF-α, and MCP-1 was upregulated by recombinant FSTL1 in a dose-dependent manner, paralleled with activation of the IKKβ-NFκB and JNK signaling pathways in the two cell lines. Moreover, FSTL1 impaired insulin signaling in 3T3-L1 adipocytes, as revealed by attenuated phosphorylation of both Akt and IRS-1 in response to insulin stimulation. Together, our results suggest that FSTL1 is a potential mediator of inflammation and insulin resistance in obesity.

The circadian clock plays an important role in the liver by regulating the major aspects of energy metabolism. Currently, it is assumed that the circadian clock regulates metabolism mostly by regulating the expression of liver enzymes at the transcriptional level, but the underlying mechanism is not well understood. In this study, we showed that Lgr4 homozygous mutant (Lgr4m/m) mice showed alteration in the rhythms of the respiratory exchange ratio. We further detected impaired plasma triglyceride rhythms in Lgr4m/m mice. Although no significant changes in plasma cholesterol rhythms were observed in the Lgr4m/m mice, their cholesterol levels were obviously lower. This phenotype was further confirmed in the context of ob/ob mice, in which lack of LGR4 dampened circadian rhythms of triglyceride. We next demonstrated that Lgr4 expression exhibited circadian rhythms in the liver tissue and primary hepatocytes in mice, but we did not detect changes in the expression levels or circadian rhythms of classic clock genes, such as Clock, Bmal1 (Arntl), Pers, Rev-erbs, and Crys, in Lgr4m/m mice compared with their littermates. Among the genes related to the lipid metabolism, we found that the diurnal expression pattern of the Mttp gene, which plays an important role in the regulation of plasma lipid levels, was impaired in Lgr4m/m mice and primary Lgr4m/m hepatocytes. Taken together, our results demonstrate that LGR4 plays an important role in the regulation of plasma lipid rhythms, partially through regulating the expression of microsomal triglyceride transfer protein. These data provide a possible link between the peripheral circadian clock and lipid metabolism. [ABSTRACT FROM AUTHOR]