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The article explores the physiological integration of taste and metabolism, emphasizing recent advancements in understanding taste perception, taste receptors, and their implications for health, particularly in the context of added sugars and nonnutritive sweeteners. It discusses the intricate mechanisms of taste transduction, debunking myths such as the tongue taste map, and sheds light on the role of extraoral taste receptors in regulating physiological balance beyond conscious gustation.

Incretins are hormones secreted from enteroendocrine cells after nutrient intake that stimulate insulin secretion from β cells in a glucose‐dependent manner. Glucose‐dependent insulinotropic polypeptide (GIP) and glucagon‐like peptide‐1 (GLP‐1) are the only two known incretins. Dysregulation of incretin secretion and actions are noted in diseases such as obesity and diabetes. In this review, we first summarize our traditional understanding of the physiology of GIP and GLP‐1, and our current knowledge of the relationships between GIP and GLP‐1 and obesity and diabetes. Next, we present the results from major randomized controlled trials on the use of GLP‐1 receptor agonists for managing type 2 diabetes, and emerging data on treating obesity and prediabetes. We conclude with a glimpse of the future with possible complex interactions between nutrients, gut microbiota, the endocannabinoid system, and enteroendocrine cells. [ABSTRACT FROM AUTHOR]

The endocannabinoid system (ECS) regulates cellular homeostasis and whole-body metabolism. There is an autonomous ECS in the endocrine pancreas, including the cannabinoid 1 receptor (CB1R) that is present in β-cells. Here, we discuss conflicts that have arisen with regard to the function(s) of the ECs in the endocrine pancreas and that have caused confusion when defining the role of the ECS in islets of Langerhans, especially the role(s) of CB1R in β-cells. We also discuss the latest data published concerning the ECS in islets. CB1R in particular is not simply a negative modulator of insulin secretion as it is also involved in intra-islet inflammation during high fat-high sugar intake and it is a negative regulator of β-cell viability and turnover. We also discuss the feasibility of using CB1R as a target for the treatment of diabetes. [ABSTRACT FROM AUTHOR]

Levels of obesity have reached epidemic proportions on a global scale, which has led to considerable increases in health problems and increased risk of several diseases, including cardiovascular and pulmonary diseases, cancer and diabetes mellitus. People with obesity consume more food than is needed to maintain an ideal body weight, despite the discrimination that accompanies being overweight and the wealth of available information that overconsumption is detrimental to health. The relationship between energy expenditure and energy intake throughout an individual's lifetime is far more complicated than previously thought. An improved comprehension of the relationships between taste, palatability, taste receptors and hedonic responses to food might lead to increased understanding of the biological underpinnings of energy acquisition, as well as why humans sometimes eat more than is needed and more than we know is healthy. This Review discusses the role of taste receptors in the tongue, gut, pancreas and brain and their hormonal involvement in taste perception, as well as the relationship between taste perception, overeating and the development of obesity. [ABSTRACT FROM AUTHOR]

The authors reflect on the U.S. Food and Drug Administration's (FDA) approval of glucagon-like peptide 1 (GLP-1) receptor agonists (exenatide) and dipeptidyl peptidase-4 (DPP4) inhibitors (sitagliptin) in 2005 and 2006, respectively. They discuss the relationship between incretin treatment and pancreatitis, and the drugs' link to pancreatitis and pancreatic cancer. They also mention a 2013 study which assessed pancreata from patients on incretin, patients on insulin, and nondiabetic patients.

Combining a tyrosine kinase inhibitor (imatinib) and a thiazolidinedione (pioglitazone) is proposed for the treatment of chronic myeloid leukemia. [ABSTRACT FROM AUTHOR]

Abstract: Glucagon-like peptide 1 (GLP-1) is a hormone that is encoded in the proglucagon gene. It is mainly produced in enteroendocrine L cells of the gut and is secreted into the blood stream when food containing fat, protein hydrolysate, and/or glucose enters the duodenum. Its particular effects on insulin and glucagon secretion have generated a flurry of research activity over the past 20 years culminating in a naturally occurring GLP-1 receptor (GLP-1R) agonist, exendin 4 (Ex-4), now being used to treat type 2 diabetes mellitus (T2DM). GLP-1 engages a specific guanine nucleotide-binding protein (G-protein) coupled receptor (GPCR) that is present in tissues other than the pancreas (brain, kidney, lung, heart, and major blood vessels). The most widely studied cell activated by GLP-1 is the insulin-secreting β cell where its defining action is augmentation of glucose-induced insulin secretion. Upon GLP-1R activation, adenylyl cyclase (AC) is activated and cAMP is generated, leading, in turn, to cAMP-dependent activation of second messenger pathways, such as the protein kinase A (PKA) and Epac pathways. As well as short-term effects of enhancing glucose-induced insulin secretion, continuous GLP-1R activation also increases insulin synthesis, β cell proliferation, and neogenesis. Although these latter effects cannot be currently monitored in humans, there are substantial improvements in glucose tolerance and increases in both first phase and plateau phase insulin secretory responses in T2DM patients treated with Ex-4. This review will focus on the effects resulting from GLP-1R activation in the pancreas. [Copyright &y& Elsevier]

A gut insulinotropic peptide, glucagon-like peptide-1 (GLP-1), when given continuously subcutaneously, has been shown to be an effective agent to treat type 2 diabetes. Because of inactivation by dipeptidyl peptidase IV (DPP IV), it has a very short half-life (90-120 s), hence the need for continuous administration. Exendin-4 is an agonist of the GLP-1 receptor. It is not a substrate for DPP IV, and we previously demonstrated that intravenous administration has potent insulinotropic properties in type 2 diabetic volunteers. We evaluated the efficacy of bolus subcutaneous exendino4 in insulin-naive type 2 diabetic volunteers. Ten patients aged 44-72 yr with mean fasting glucose levels of 11.4 ± 0.9 mmol/l were enrolled, and daily or twice-daily bolus subcutaneous exendin-4 was selfadministered for i mo. Glycosylated hemoglobin, multiple daily capillary blood glucose, β-cell sensitivity to glucose, and peripheral tissue sensitivity to insulin were compared before and after treatment. The greatest decline in capillary blood glucose was seen before bed, with a drop from 15.5 to 9.2 mmol/l (P < 0.0001). Glycosylated hemoglobin improved significantly with treatment, from 9.1 to 8.3% (P = 0.009). β-Cell sensitivity to glucose was improved, as assessed by C-peptide levels during a hyperglycemic clamp. No significant adverse effects were noted or reported. Our data suggest that, even with this short duration of therapy, exendin-4 treatment had a significant effect on glucose homeostasis. [ABSTRACT FROM AUTHOR]

Diabetes resulting from heterozygosity for an inactivating mutation of the homeodomain transcription factor insulin promoter factor 1 (IPF-1) is due to a genetic defect of beta-cell function referred to as maturity-onset diabetes of the young 4. IPF-1 is required for the development of the pancreas and mediates glucose-responsive stimulation of insulin gene transcription. To quantitate islet cell responses in a family harboring a Pro63fsdelC mutation in IPF-1, we performed a five-step (1-h intervals) hyperglycemic clamp on seven heterozygous members (NM) and eight normal genotype members (NN). During the last 30 min of the fifth glucose step, glucagon-like peptide 1 (GLP-1) was also infused (1.5 pmol x kg(-1) x min(-1)). Fasting plasma glucose levels were greater in the NM group than in the NN group (9.2 vs. 5.9 mmol/l, respectively; P < 0.05). Fasting insulin levels were similar in both groups (72 vs. 105 pmol/l for NN vs. NM, respectively). First-phase insulin and C-peptide responses were absent in individuals in the NM group, who had markedly attenuated insulin responses to glucose alone compared with the NN group. At a glucose level of 16.8 mmol/l above fasting level, GLP-1 augmented insulin secretion equivalently (fold increase) in both groups, but the insulin and C-peptide responses to GLP-1 were sevenfold less in the NM subjects than in the NN subjects. In both groups, glucagon levels fell during each glycemic plateau, and a further reduction occurred during the GLP-1 infusion. Sigmoidal dose-response curves of glucose clearance versus insulin levels during the hyperglycemic clamp in the two small groups showed both a left shift and a lower maximal response in the NM group compared with the NN group, which is consistent with an increased insulin sensitivity in the NM subjects. A sharp decline occurred in the dose-response curve for suppression of nonesterified fatty acids versus insulin levels in the NM group. We conclude that the Pro63fsdelC IPF-1 mutation is associated with a severe impairment of beta-cell sensitivity to glucose and an apparent increase in peripheral tissue sensitivity to insulin and is a genetically determined cause of beta-cell dysfunction. [ABSTRACT FROM AUTHOR]

• Meta-analysis of RCTs showed that administration of oral medium chain triglycerides induced mild ketosis in AD. • Meta-analysis of RCTs showed that oral medium chain triglycerides improved performance on a combined cognitive measure in AD. • Risk of bias of existing studies necessitates future clinical trials on the effects of medium chain triglycerides in AD. The brain in Alzheimer's disease shows glucose hypometabolism but may utilize ketones for energy production. Ketone levels can potentially be boosted through oral intake of Medium Chain Triglycerides (MCTs). The aim of this meta-analysis is to investigate the effect of MCTs on peripheral ketone levels and cognitive performance in patients with mild cognitive impairment and Alzheimer's disease. Medline, Scopus and Web of Science were searched for literature up to March 1, 2019. Meta-analyses were performed by implementing continuous random-effects models and outcomes were reported as weighted Mean Differences (MDs) or Standardized Mean Differences (SMDs). Twelve records (422 participants) were included. Meta-analysis of RCTs showed that, compared with placebo, MCTs elevated beta-hydroxybutyrate [MD = 0.355; 95 % CI (0.286, 0.424), I 2 = 0 %], showed a trend towards cognitive improvement on ADAS-Cog [MD = −0.539; 95% CI (−1.239, −0.161), I2 = 0 %], and significantly improved cognition on a combined measure (ADAS-Cog with MMSE) [SMD = −0.289; 95 % CI (−0.551, −0.027), I2 = 0 %]. In this meta-analysis, we demonstrated that MCTs can induce mild ketosis and may improve cognition in patients with mild cognitive impairment and Alzheimer's disease. However, risk of bias of existing studies necessitates future trials. [ABSTRACT FROM AUTHOR]

Approximately 1.25 million Americans have type 1 diabetes mellitus (T1DM), resulting from β-cell destruction. There is no known way to prevent it or to stop destruction of any remaining β-cells. Although the cannabinoid system, specifically cannabinoid 1 receptor (CB1R), is implicated in obesity and T2DM, its role, if any, in T1DM has not been studied. To address this, we induced β-cell destruction in wild type mice (WT: n=8) and mice in which CB1R was genetically nullified in β-cells only (β-CB1R-/-: n=8) in adulthood by five injections of streptozotocin (50 mg/kg intraperitoneally [IP]), a toxin selective for β-cells. We found that β-CB1R-/- mice had random blood glucose (BG) levels in the range of 137-289 mg/dL throughout the study period (28 days) as well as preserved insulin secretion with superior glucose tolerance after IP glucose (2g/kg) at day 8, 15 or 27, relative to their (random BG 500-600 mg/dL) WT littermates. CB1R knockout drove significant increases in pancreatic islet autophagic activity based on increased accumulation of autophagosome hallmarks (LC3B, Beclin-1, ATG5 and ATG7) and reduced p62 expression. Insulin and LC3B were colocalized in CB1R-deficient β-cells. Remarkably, the islets did not show the upregulation of ER unfolded protein response, which was present in β-cells of WT mice, while exerting the induction of protective chaperones. These anti-stress functions were accompanied by increased phosphorylation of AKT (ser) 473 and ERK in β-cells, which reveals a previously unrecognized route for PI3K-AKT pathway to activate the anti-apoptotic NFkB/p65 signaling that coordinately is permissive to β-cell survival. We conclude that CB1R nullification restores autophagy machinery as a novel signaling pathway to counteract ER stress-mediated cell death and confers resistance to β-cell destruction. We propose that CB1R is a potential therapeutic target during the honeymoon phase of T1DM. Disclosure: K. Aseer: None. J.M. Egan: None. [ABSTRACT FROM AUTHOR]

Cannabinoid 1 receptors (CB1Rs) are G protein-coupled receptors that are present in peripheral organs such as liver, pancreas, adipose tissue and skeletal muscle where they are involved in fine-tuning many metabolic functions. It was previously reported that liver-specific genetic deletion of CB1R (hCNR1-/-) mice fed high fat diets (HFD) had similar body weight to HFD-fed hCNR1+/+ mice, but they retained insulin sensitivity comparable to normal chow-fed (NCD) hCNR1+/+ mice. Therefore, this study was undertaken to uncover how hCB1Rs impact the insulin signaling pathway. Male hCNR1-/- and hCNR1+/+ mice were fed with a high fat high sugar diet (HFSD: N = 8-12) for 15 weeks. In contrast with the previous study of HFD only, HFSD-fed hCNR1-/- mice had less body weight gain than HFSD-fed hCNR1+/+ mice (25.1±2.7 vs. 19.8±1.7g), less fat accumulation in the liver, 1.3-fold increase in glucose disposal and 1.7-fold increase in insulin sensitivity compared to HFSD-fed hCNR1+/+ mice. Further study demonstrated that the lack of hepatic CB1R resulted in upregulated phosphorylation in liver of protein kinase B (AKT), causing activation of downstream target molecules, such as proline-rich AKT substrate 40 (PRAS40) in the mammalian target of rapamycin complex 1 (mTORC1). Similarly, primary hepatocytes isolated from hCNR1-/- mice had increased amounts of phosphorylated AKT and PRAS40 in comparison to hepatocytes from hCNR1+/+ mice. The co-immunoprecipitation studies clearly revealed hepatic CB1R modulates insulin signaling by the association or dissociation of the components of mTORC1. In support of these data, the deficiency of hepatic CB1R leads to upregulation of phosphoinositide 3-kinase (PI3K) class IB, p110γ, resulting in increased association between p110γ and G-protein beta. These findings indicate that genetic deletion of hepatic CB1R contributes to improved glucose homeostasis. Therefore, modulation of CB1R activity in liver may be a useful therapeutic in obese and diabetic individuals. Disclosure: Y. Kim: None. J.M. Egan: None. [ABSTRACT FROM AUTHOR]

Simple Summary: The aim of this study was to explore the potential impact of red ginseng (RG) on age-associated cellular senescence through in vitro, ex vivo, and 19-month-old aged mouse models. In addition to enhancing insulin homeostasis, RG supplementation modified the canonical cellular senescence pathway and inhibited apoptotic markers. Moreover, RG significantly reduced the senescence-associated inflammatory pathway in the liver. Finally, the RG treatment mitigated cellular senescence in primary hepatocytes and mouse embryonic fibroblasts. In conclusion, these findings suggest that RG has a positive influence on the aging process by regulating hepatic cellular senescence and age-related phenotypes. Cellular senescence is defined as an irreversible cell cycle arrest accompanied by morphological and physiological alterations during aging. Red ginseng (RG), processed from fresh ginseng (Panax ginseng C.A. Meyer) with a one-time steaming and drying process, is a well-known beneficial herbal medicine showing antioxidant, anti-inflammatory, and anti-aging properties. The current study aimed to investigate the benefits of RG in alleviating hepatic cellular senescence and its adverse effects in 19-month-old aged mice. We applied two different intervention methods and durations to compare RG's effects in a time-dependent manner: (1) oral gavage injection for 4 weeks and (2) ad libitum intervention for 14 weeks. We observed that 4-week RG administration was exerted to maintain insulin homeostasis against developing age-associated insulin insensitivity and suppressed cellular senescence pathway in the liver and primary hepatocytes. Moreover, with remarkable improvement of insulin homeostasis, 14-week RG supplementation downregulated the activation of c-Jun N-terminal kinase (JNK) and its downstream transcriptional factor nuclear factor-κB (NF-κB) in aged mice. Lastly, RG treatment significantly reduced the senescence-associated β-galactosidase (SA-β-gal)-positive cells in primary hepatocytes and ionizing radiation (IR)-exposed mouse embryonic fibroblasts (MEFs). Taken together, we suggest that RG can be a promising candidate for a senolytic substance by preventing hepatic cellular senescence. [ABSTRACT FROM AUTHOR]

The study of age‐related biomarkers from different biofluids and tissues within the same individual might provide a more comprehensive understanding of age‐related changes within and between compartments as these changes are likely highly interconnected. Understanding age‐related differences by compartments may shed light on the mechanism of their reciprocal interactions, which may contribute to the phenotypic manifestations of aging. To study such possible interactions, we carried out a targeted metabolomic analysis of plasma, skeletal muscle, and urine collected from healthy participants, age 22–92 years, and identified 92, 34, and 35 age‐associated metabolites, respectively. The metabolic pathways that were identified across compartments included inflammation and cellular senescence, microbial metabolism, mitochondrial health, sphingolipid metabolism, lysosomal membrane permeabilization, vascular aging, and kidney function. [ABSTRACT FROM AUTHOR]

Cannabinoid receptors (CBR), including CB1 and CB2 have been therapeutic targets for a number of conditions. Recently, splice variants of the CB1R have been identified in humans. The isoforms differ in their N-terminus sequence and pharmacological activity relative to the CB1R, as a result, the differentiation between the CB1 receptor and its isoform is required. As a result, a selected reaction monitoring mass spectrometry (SRM-MS) method was developed for the quantitation of CB1 and the CB1b isoform in CHO cells transduced with CB1 and CB1b. The SRM-MS protocol was assessed with isotopically labeled peptide standards and had high reproducibility of intra-day assay (CVs from 1.9 to 4.3% for CB1 and 0.5 to 5.9% for CB1b) and inter-day assay (CVs from 1.2 to 5.2% for CB1 and 1.2 to 6.1% for CB1b). [ABSTRACT FROM AUTHOR]

The tongue is a complex multifunctional organ that interacts and senses both interoceptively and exteroceptively. Although it is easily visible to almost all of us, it is relatively understudied and what is in the literature is often contradictory or is not comprehensively reported. The tongue is both a motor and a sensory organ: motor in that it is required for speech and mastication, and sensory in that it receives information to be relayed to the central nervous system pertaining to the safety and quality of the contents of the oral cavity. Additionally, the tongue and its taste apparatus form part of an innate immune surveillance system. For example, loss or alteration in taste perception can be an early indication of infection as became evident during the present global SARS-CoV-2 pandemic. Here, we particularly emphasize the latest updates in the mechanisms of taste perception, taste bud formation and adult taste bud renewal, and the presence and effects of hormones on taste perception, review the understudied lingual immune system with specific reference to SARS-CoV-2, discuss nascent work on tongue microbiome, as well as address the effect of systemic disease on tongue structure and function, especially in relation to taste. [ABSTRACT FROM AUTHOR]

(1) Background and aims: Amyloidosis due to aggregation of amyloid-β (Aβ42) is a key pathogenic event in Alzheimer's disease (AD), whereas aggregation of mature islet amyloid polypeptide (IAPP37) in human islets leads to β-cell dysfunction. The aim of this study is to uncover potential biomarkers that might additionally point to therapy for early AD patients. (2) Methods: We used bioinformatic approach to uncover novel IAPP isoforms and developed a quantitative selective reaction monitoring (SRM) proteomic assay to measure their peptide levels in human plasma and CSF from individuals with early AD and controls, as well as postmortem cerebrum of clinical confirmed AD and controls. We used Thioflavin T amyloid reporter assay to measure the IAPP isoform fibrillation propensity and anti-amyloid potential against aggregation of Aβ42 and IAPP37. (3) Results: We uncovered hominid-specific IAPP isoforms: hIAPPβ, which encodes an elongated propeptide, and hIAPPγ, which is processed to mature IAPP25 instead of IAPP37. We found that hIAPPβ was significantly reduced in the plasma of AD patients with the accuracy of 89%. We uncovered that IAPP25 and a GDNF derived DNSP11 were nonaggregating peptides that inhibited the aggregation of IAPP37 and Aβ42. (4) Conclusions: The novel peptides derived from hIAPP isoforms have potential to serve as blood-derived biomarkers for early AD and be developed as peptide based anti-amyloid medicine. [ABSTRACT FROM AUTHOR]

Sodium-glucose cotransporter-2 inhibitors (SGLT2is), such as empagliflozin, lower blood glucose in type 2 diabetes mellitus and improve cardiorenal outcomes regardless of diabetes presence. Whether SGLT2is exert any effects on the brain's metabolism has not been studied. We conducted a single-arm clinical trial to investigate the effects of once daily administration of oral empagliflozin (25 mg) for 14 days on systemic and brain metabolism in 21 non-diabetics aged 55 years old or older. Empagliflozin lowered circulating insulin and elevated β-hydroxybutyrate over 34-h periods, both following its first administration and after 14 days of daily administration, with minor alterations in glucose homeostasis. Levels of phosphorylated insulin-like growth factor-1 receptor (pIGF-1R), phosphorylated insulin receptor (pIR), phosphorylated-in-tyrosine insulin receptor substrate-1 (pY-IRS-1), and phosphorylated protein kinase B or AKT (pAKT) were increased in extracellular vesicles enriched for neuronal origin (NEVs) following the first empagliflozin administration, but not after 14 days. Our finding of IGF-1R upregulation in NEVs is promising because several post-mortem and epidemiological studies support the idea that upregulation of IGF signaling may protect against Alzheimer's disease (AD). Moreover, our finding showing activation of insulin signaling and, in particular, the canonical pathway (pIR, pY-IRS-1, pAKT) in NEVs is important because such changes have been repeatedly associated with neuronal survival. Using brain magnetic resonance spectroscopy (MRS), we detected decreased concentrations of the excitatory neurotransmitter glutamate and its precursor glutamine after empagliflozin administration. This finding is also encouraging since glutamatergic excitotoxicity has long been implicated in AD pathology. Overall, our findings may motivate the repurposing of SGLT2is for use in AD and other, related diseases that are characterized by downregulation of IGF-1/insulin signaling in neurons and excitotoxicity. [ABSTRACT FROM AUTHOR]

Simple Summary: The goal of this study was to examine if BG impacts the aging process, specifically cellular senescence, using in vitro and aged mouse models. Primary mouse embryonic fibroblasts (MEFs) and aged mice (18 months old) showed that BG supplementation retarded cellular senescence. Of note, BG-supplemented aged mice had remarkedly altered hepatic genes involved in the aging process as it caused less activation of the canonical senescence pathway. These observations demonstrated that BG positively impacts the age-related phenotype by controlling the expression of cellular senescence in the liver and other metabolic organs such as skeletal muscle and white adipose tissue. Cellular senescence, one of the hallmarks of aging, refers to permanent cell cycle arrest and is accelerated during the aging process. Black ginseng (BG), prepared by a repeated steaming and drying process nine times from fresh ginseng (Panax ginseng C.A. Meyer), is garnering attention for herbal medicine due to its physiological benefits against reactive oxygen species (ROS), inflammation, and oncogenesis, which are common cues to induce aging. However, which key nodules in the cellular senescence process are regulated by BG supplementation has not been elucidated yet. In this study, we investigated the effects of BG on cellular senescence using in vitro and aged mouse models. BG-treated primary mouse embryonic fibroblasts (MEFs) in which senescence was triggered by ionizing radiation (IR) expressed less senescence-associated β-galactosidase (SA-β-gal)-positive stained cells. In our aged mice (18 months old) study, BG supplementation (300 mg/kg) for 4 weeks altered hepatic genes involved in the aging process. Furthermore, we found BG supplementation downregulated age-related inflammatory genes, especially in the complement system. Based on this observation, we demonstrated that BG supplementation led to less activation of the canonical senescence pathway, p53-dependent p21 and p16, in multiple metabolic organs such as liver, skeletal muscle and white adipose tissue. Thus, we suggest that BG is a potential senolytic candidate that retards cellular senescence. [ABSTRACT FROM AUTHOR]

Identifying predictors of mild cognitive impairment (MCI) and Alzheimer׳s disease (AD) can lead to more accurate diagnosis and facilitate clinical trial participation. We identified 320 participants (93 cognitively normal or CN, 162 MCI, 65 AD) with baseline magnetic resonance imaging (MRI) data, cerebrospinal fluid biomarkers, and cognition data in the Alzheimer׳s Disease Neuroimaging Initiative database. We used independent component analysis (ICA) on structural MR images to derive 30 matter covariance patterns (ICs) across all participants. These ICs were used in iterative and stepwise discriminant classifier analyses to predict diagnostic classification at 24 months for CN vs. MCI, CN vs. AD, MCI vs. AD, and stable MCI (MCI-S) vs. MCI progression to AD (MCI-P). Models were cross-validated with a “leave-10-out” procedure. For CN vs. MCI, 84.7% accuracy was achieved based on cognitive performance measures, ICs, p-tau 181p , and ApoE ε4 status. For CN vs. AD, 94.8% accuracy was achieved based on cognitive performance measures, ICs, and p-tau 181p . For MCI vs. AD and MCI-S vs. MCI-P, models achieved 83.1% and 80.3% accuracy, respectively, based on cognitive performance measures, ICs, and p-tau 181p . ICA-derived MRI biomarkers achieve excellent diagnostic accuracy for MCI conversion, which is little improved by CSF biomarkers and ApoE ε4 status. [ABSTRACT FROM AUTHOR]

Resveratrol (RES) and curcumin (CUR) are polyphenols that are found in fruits and turmeric, and possess medicinal properties that are beneficial in various diseases, such as heart disease, jf cancer, and type 2 diabetes mellitus (T2DM). Results from recent studies have indicated that J their therapeutic properties can be attributed to their anti-inflammatory effects. Owing to _o reports stating that they protect against ß-cell dysfunction, we studied their mechanism(s) £ of action in ß-cells. In T2DM, cAMP plays a critical role in glucose- and incretin-stimulated insulin secretion as well as overall pancreatic ß-cell health. A potential therapeutic target in I the management of T2DM lies in regulating the activity of phosphodiesterases (PDEs), which o degrade cAMP. Both RES and CUR have been reported to act as PDE inhibitors in various cell types, but it remains unknown if they do so in pancreatic ß-cells. In our current study, we found that both RES (0.1-10 mmol/l) and CUR (1-100 pmol/l)-regulated insulin secretion under glucose-stimulated conditions. Additionally, treating ß-cell lines and human islets with these polyphenols led to increased intracellular cAMP levels in a manner similar to 3-isobutyl-1-methylxanthine, a classic PDE inhibitor. When we investigated the effects of RES and CUR on PDEs, we found that treatment significantly downregulated the mRNA expression of most of the 11 PDE isozymes, including PDE3B, PDE8A, and PDE10A, which have been linked previously to regulation of insulin secretion in islets. Furthermore, RES and CUR inhibited PDE activity in a dose-dependent manner in ß-cell lines and human islets. Collectively, we demonstrate a novel role for natural-occurring polyphenols as PDE inhibitors that enhance pancreatic ß-cell function. [ABSTRACT FROM AUTHOR]

Extracellular vesicles (EVs) are involved in intercellular communication and are a topic of increasing interest due to their therapeutic potential. The aim of this study was to determine whether human islet-derived EVs contain insulin, and if so, what role do they play in glucose stimulated insulin secretion. We isolated EVs from human islets culture and plasma to probe for insulin. Plasma from hyperglycemic glucose clamp experiments were also used to isolate and measure EV insulin content in response to a secretory stimulus. We performed immunogold electron microscopy for insulin presence in EVs. Co-culture experiments of isolated EVs with fresh islets were performed to examine the effect of EV cargo on insulin receptor signaling. EVs isolated from culture medium contained insulin. Glucose treatment of islets increased the level of EV insulin. Hyperglycemic glucose clamp experiments in humans also lead to increased levels of insulin in plasma-derived EVs. Immunogold electron microscopy and proteinase K-digestion experiments demonstrated that insulin in EVs predominantly associated with the exterior surface of EVs while western blot analyses uncovered the presence of only preproinsulin in EVs. Membrane-bound preproinsulin in EVs was capable of activating insulin signaling pathway in an insulin receptor-dependent manner. The physiological relevance of this finding was observed in priming of human naïve islets by EVs during glucose stimulated insulin secretion. Our data suggest that (1) human islets secret insulin via an alternate pathway (EV-mediated) other than conventional granule-mediated insulin secretion, and (2) EV membrane bound preproinsulin is biologically active. [ABSTRACT FROM AUTHOR]

Human insulin (INS) gene diverged from the ancestral genes of invertebrate and mammalian species millions of years ago. We previously found that mouse insulin gene (Ins2) isoforms are expressed in brain choroid plexus (ChP) epithelium cells, where insulin secretion is regulated by serotonin and not by glucose. We further compared human INS isoform expression in postmortem ChP and islets of Langerhans. We uncovered novel INS upstream open reading frame isoforms and their protein products. In addition, we found a novel alternatively spliced isoform that translates to a 74-amino acid (AA) proinsulin containing a shorter 19-AA C-peptide sequence, herein designated Cα-peptide. The middle portion of the conventional C-peptide contains β-sheet (GQVEL) and hairpin (GGGPG) motifs that are not present in Cα-peptide. Islet amyloid polypeptide (IAPP) is not expressed in ChP, and its amyloid formation was inhibited in vitro more efficiently by Cα-peptide than by C-peptide. Of clinical relevance, the ratio of the 74-AA proinsulin to proconvertase-processed Cα-peptide was significantly increased in islets from type 2 diabetes mellitus autopsy donors. Intriguingly, 100 years after the discovery of insulin, we found that INS isoforms are present in ChP from insulin-deficient autopsy donors. [ABSTRACT FROM AUTHOR]

The gustatory system provides critical information about the quality and nutritional value of food before it is ingested. Thus, physiological mechanisms that modulate taste function in the context of nutritional needs or metabolic status could optimize ingestive decisions. We report that glucagon, which plays important roles in the maintenance of glucose homeostasis, enhances sweet taste responsiveness through local actions in the mouse gustatory epithelium. Using immunohistochemistry and confocal microscopy, we found that glucagon and its receptor (GlucR) are coexpressed in a subset of mouse taste receptor cells. Most of these cells also express the T1R3 taste receptor implicated in sweet and/or umami taste. Genetic or pharmacological disruption of glucagon signaling in behaving mice indicated a critical role for glucagon in the modulation of taste responsiveness. Scg5-/- mice, which lack mature glucagon, had significantly reduced responsiveness to sucrose as compared to wild-type littermates in brief-access taste tests. No significant differences were seen in responses to prototypical salty, sour, or bitter stimuli. Taste responsiveness to sucrose was similarly reduced upon acute and local disruption of glucagon signaling by the GlucR antagonist L-168,049. Together, these data indicate a role for local glucagon signaling in the peripheral modulation of sweet taste responsiveness. [ABSTRACT FROM AUTHOR]

In mice, cellular senescence and senescence‐associated secretory phenotype (SASP) positively contribute to cutaneous wound healing. In this proof‐of‐concept study, we investigated the expressions of p16, p21, and other senescence‐associated biomarkers during human wound healing in 24 healthy subjects using a double‐biopsy experimental design. The first punch biopsy created the wound and established the baseline. The second biopsy, concentric to the first and taken several days after wounding, was used to probe for expression of biomarkers by immunohistochemistry and RNA FISH. To assess the effects of age, we recruited 12 sex‐matched younger (30.2 ± 1.3 years) and 12 sex‐matched older (75.6 ± 1.8 years) subjects. We found that p21 and p53, but not p16, were induced during healing in younger, but not older subjects. A role for Notch signaling in p21 expression was inferred from the inducible activation of HES1. Further, other SASP biomarkers such as dipeptidyl peptidase‐4 (DPP4) were significantly induced upon wounding in both younger and older groups, whereas matrix metallopeptidase 9 (MMP9) was induced only in the younger group. Senescence‐associated β‐galactosidase (SA‐β‐gal) was not detectable before or after wounding. This pilot study suggests the possibility that human cutaneous wound healing is characterized by differential expression of p21 and p53 between younger and older subjects. [ABSTRACT FROM AUTHOR]

Approximately 1.25 million Americans have type 1 diabetes mellitus (T1DM), resulting from autoimmune β-cell destruction: there is no known way to prevent such destruction of β-cells. We have already reported that activation of cannabinoid 1 receptor (CB1R) contributes to the pathogenesis of pancreatic β-cell dysfunction during high fat feeding. To uncover if CB1R signaling might influence toxin-induced β-cell injury, we induced β-cell destruction in wild type mice (WT: n=8) and in mice in which CB1R was genetically nullified in β-cells only (β-CB1R-/-: n=8) in adulthood by five daily injections of streptozotocin (STZ; 50 mg/kg intraperitoneally [IP]), a toxin selective for β-cells. We found that β-CB1R-/- mice had random blood glucose (BG) levels in the range of 137-220 mg/dL throughout the study period (28 days following STZ) as well as preserved insulin secretion with superior glucose tolerance after a glucose challenge (2g/kg) at day 8, 15 or 27, relative to their WT littermates (random BG 500-600 mg/dL). CB1R-deficient β-cells exhibited significant increases in autophagy flux following STZ. We determined that mice or β-cells lacking CB1R had reduced mTOR activation and increased nuclear translocation of TFEB, a key prerequisite for lysosome biogenesis and autophagy. Importantly, we found that CB1R deletion protected against oxidative stress, endoplasmic reticulum stress, and prevented the induction of apoptosis by STZ. These anti-stress functions were accompanied by increased phosphorylation of AKT (ser) 473 and ERK1/2 in β-cells, which reveals a previously unrecognized route for mTOR/AKT axis to regulate autophagy that coordinately is permissive to β-cell survival. We conclude that CB1R nullification confers resistance to pancreatic β-cell dysfunction by upregulating autophagy and subsequently antagonizing the decline in lysosomal activity. Altogether, we propose that CB1R is a potential therapeutic target during the honeymoon phase of T1DM. Disclosure: K. Aseer: None. J.F. O'Connell: None. J.M. Egan: None. [ABSTRACT FROM AUTHOR]

Chronic alcohol feeding increases the levels of 2-arachidonoylglycerol (2-AG) in the liver, which activates hepatic cannabinoid receptor type 1 (CB1R), leading to oxidative liver injury. 2-AG biosynthesis is catalyzed by diacylglycerol lipase (DAGL). However, the mechanisms regulating hepatic DAGL gene expression and 2-AG production are largely unknown. In this study, we show that CB1R-induced estrogen-related receptor γ (ERRγ) controls hepatic DAGL gene expression and 2-AG levels. Arachidonyl-2′-chloroethylamide (ACEA), a synthetic CB1R agonist, significantly upregulated ERRγ, DAGLα, and DAGLβ, and increased 2-AG levels in the liver (10 mg/kg) and hepatocytes (10 μM) of wild-type (WT) mice. ERRγ overexpression upregulated DAGLα and DAGLβ expressions and increased 2-AG levels, whereas ERRγ knockdown abolished ACEA-induced DAGLα, DAGLβ, and 2-AG in vitro and in vivo. Promoter assays showed that ERRγ positively regulated DAGLα and DAGLβ transcription by binding to the ERR response element in the DAGLα and DAGLβ promoters. Chronic alcohol feeding (27.5% of total calories) induced hepatic steatosis and upregulated ERRγ, leading to increased DAGLα, DAGLβ, or 2-AG in WT mice, whereas these alcohol-induced effects did not occur in hepatocyte-specific CB1R knockout mice or in those treated with the ERRγ inverse agonist GSK5182 (40 mg/kg in mice and 10 μM in vitro). Taken together, these results indicate that suppression of alcohol-induced DAGLα and DAGLβ gene expressions and 2-AG levels by an ERRγ-specific inverse agonist may be a novel and attractive therapeutic approach for the treatment of alcoholic liver disease. [ABSTRACT FROM AUTHOR]

Sarcopenic obesity, the combination of skeletal muscle mass and function loss with an increase in body fat, is associated with physical limitations, cardiovascular diseases, metabolic stress, and increased risk of mortality. Cannabinoid receptor type 1 (CB1R) plays a critical role in the regulation of whole-body energy metabolism because of its involvement in controlling appetite, fuel distribution, and utilization. Inhibition of CB1R improves insulin secretion and insulin sensitivity in pancreatic β-cells and hepatocytes. We have now developed a skeletal muscle-specific CB1R-knockout (Skm-CB1R-/-) mouse to study the specific role of CB1R in muscle. Muscle-CB1R ablation prevented diet-induced and age-induced insulin resistance by increasing IR signaling. Moreover, muscle-CB1R ablation enhanced AKT signaling, reducing myostatin expression and increasing IL-6 secretion. Subsequently, muscle-CB1R ablation increased myogenesis through its action on MAPK-mediated myogenic gene expression. Consequently, Skm-CB1R-/- mice had increased muscle mass and whole-body lean/fat ratio in obesity and aging. Muscle-CB1R ablation improved mitochondrial performance, leading to increased whole-body muscle energy expenditure and improved physical endurance, with no change in body weight. These results collectively show that CB1R in muscle is sufficient to regulate whole-body metabolism and physical performance and is a novel target for the treatment of sarcopenic obesity. [ABSTRACT FROM AUTHOR]

Objective: Insulin-like growth factor-binding protein-2 (IGFBP-2) concentrations are low in subjects with metabolic syndrome and type 2 diabetes. Intriguingly, recent studies have demonstrated an association between high IGFBP-2 concentrations and increased mortality not only in populations with certain types of cancer, but also in relatively healthy populations. We evaluated the role of IGFBP-2 in relation to BMI and mortality. Design and Participants: BMI, insulin sensitivity, insulin-like growth factor 1 (IGF-I) and IGFBP-2 were assessed repeatedly in 539 participants of the Baltimore Longitudinal St udy of Aging around the ages of 55, 65 and 75 years. Results: IGFBP-2 concentrations positively correlated with insulin sensitivity and inversely with BMI, both at baseline and follow-up. Independent of IGF-I, sex, BMI and insulin sensitivity, circulating IGFBP-2 levels positively correlated with age (P < 0.001). Changes over time in BMI were associated with an inver se correlation in IGFBP-2 concentrations. Furthermore, we found indications of a relationship between low baseline IGFBP-2 levels and mortality. Remarkably, after adjustment for insulin sensitivity, the opposite association was found, as a unit increase of log(IGFBP2) was associated with an increase in the log hazard by 1.43 (95% CI: 0.3-2.6). This accounted for both baseline (P = 0.02) as well as serial (P < 0.001) measurements of IGFBP2. Finally, in this longitudinal st udy, we found that IGF-I concentrations increased with age (0.82 ± 0.2 (μg/L)/year, P < 0.001). Conclusion: This is the first study investigating the relationship between IGFBP-2 levels and age in a longitudinal setting. Serum IGFBP-2 levels increase with age after the age of 50 year s and evolve in parallel with insulin sensitivity. IGFBP-2 may therefore be a potential marker for insulin sensitivity. We further show that IGFBP-2 levels can predict mortality in this aging population. However, its predictive value for mortality can only be interpreted in relation to insulin sensitivity. After adjustment for insulin sensitivity, high IGFBP-2 levels are predictive of increased mortality. [ABSTRACT FROM AUTHOR]

Background: Growth and differentiation factors 8 (GDF8) and 11 (GDF11) have attracted attention as targets for rejuvenating interventions. The biological activity of these proteins may be affected by circulating antagonists such as their respective prodomains, follistatin (FST315), WFIKKN1, and WFIKKN2. Reports of the relationship of GDF8 and GDF11 and their antagonists with aging and aging phenotypes such as skeletal muscle strength have been conflicting possibly because of difficulties in measuring these proteins and polypeptides.Methods: Plasma GDF8 and GDF11 and their antagonists were measured using a multiplexed selected reaction monitoring assay and liquid chromatography-tandem mass spectrometry in 160 healthy adults aged 22-93 years. Quadriceps strength was measured by knee extensor torque using isokinetic dynamometry.Results: Spearman correlations with age were the following: GDF11 prodomain (r = .30, p = .001), GDF11 mature protein (r = .23, p = .004), FST315 (r = .32, p < .0001), WFIKKN1 (r = -.21, p = 0.008), and WFIKKN2 (r = .18, p = .02). Independent of age, FST315 and WFIKKN1 were negatively associated with knee strength (p = .02, p = .03, respectively) in a multivariable model that included both GDF8 and GDF11 mature proteins.Conclusions: When measured by an antibody-free selected reaction monitoring assay, GDF8, GDF11, and their antagonists are found in the circulation in the ng/mL range. In healthy adults, plasma GDF11 and antagonists FST315, WFIKKN1, and WFIKKN2 differed by age. Antagonists of GDF8 and GDF11, but not GDF8 and GDF11, were independently associated with skeletal muscle strength. Further work is needed to characterize the relationship of these protein and polypeptides with sarcopenia-related phenotypes such as physical function and walking disability. [ABSTRACT FROM AUTHOR]

Low‐calorie sweeteners (LCSs) are widely used for weight control despite limited evidence of their effectiveness and studies linking LCS consumption with incident obesity. We tested the hypothesis that regular LCS consumption is associated with higher postprandial glucose‐dependent insulinotropic polypeptide (GIP) secretion, which has been linked to obesity. We used data from participants in the Baltimore Longitudinal Study of Aging who had completed a diet diary, had at least one visit during which they underwent an oral glucose tolerance test (OGTT), and had no diabetes. Of 232 participants, 166 contributed 1, 39 contributed 2, and 27 contributed 3 visits, and 96 (41%) reported using LCS. Plasma OGTT samples were analysed for glucose, insulin and GIP. Fasting glucose, insulin and GIP levels were no different between LCS users and non‐users. The association of LCS use with 2‐hour OGTT responses after adjustment for covariates was non‐significant for glucose (P = .98) and insulin (P = .18), but significant for greater increase in GIP in LCS users (P = .037). Regular consumption of LCSs was associated with greater increases in GIP secretion after food intake, which may potentially lead to weight gain through the lipogenic properties of GIP. [ABSTRACT FROM AUTHOR]

Epigenetic alterations are a key hallmark of aging but have been limitedly explored in tissues. Here, using naturally aged murine liver as a model and extending to other quiescent tissues, we find that aging is driven by temporal chromatin alterations that promote a refractory cellular state and compromise cellular identity. Using an integrated multi-omics approach and the first direct visualization of aged chromatin, we find that globally, old cells show H3K27me3-driven broad heterochromatinization and transcriptional suppression. At the local level, site-specific loss of H3K27me3 over promoters of genes encoding developmental transcription factors leads to expression of otherwise non-hepatocyte markers. Interestingly, liver regeneration reverses H3K27me3 patterns and rejuvenates multiple molecular and physiological aspects of the aged liver. [Display omitted] • Global increase of H3K27me3 is a common signature of aged liver and other tissues • H3K27me3 is lost at peak regions and gained at lamin-associated domains • Liver regeneration reverses age-related H3K27me3 and transcriptomic patterns Yang et al. find that the histone modification H3K27me3 accumulates in many tissues with age, due to increased time in quiescence. H3K27me3 is gained over lamin-associated domains but reduced at developmental gene promoters with consequent changes in global and local transcription. Liver regeneration breaks quiescence and partially restores youthful patterns. [ABSTRACT FROM AUTHOR]

Purpose To develop a protocol to non-invasively measure and map fat fraction, fat/(fat+water), as a function of age in the adult thymus for future studies monitoring the effects of interventions aimed at promoting thymic rejuvenation and preservation of immunity in older adults. Materials and methods Three-dimensional spoiled gradient echo 3T MRI with 3-point Dixon fat-water separation was performed at full inspiration for thymus conspicuity in 36 volunteers 19 to 56 years old. Reproducible breath-holding was facilitated by real-time pressure recording external to the console. The MRI method was validated against localized spectroscopy in vivo, with ECG triggering to compensate for stretching during the cardiac cycle. Fat fractions were corrected for T 1 and T 2 bias using relaxation times measured using inversion recovery-prepared PRESS with incremented echo time. Results In thymus at 3 T, T 1water  = 978 ± 75 ms, T 1fat  = 323 ± 37 ms, T 2water  = 43.4 ± 9.7 ms and T 2fat  = 52.1 ± 7.6 ms were measured. Mean T 1 -corrected MRI fat fractions varied from 0.2 to 0.8 and were positively correlated with age, weight and body mass index (BMI). In subjects with matching MRI and MRS fat fraction measurements, the difference between these measurements exhibited a mean of −0.008 with a 95% confidence interval of (0.123, −0.138). Conclusions 3-point Dixon MRI of the thymus with T 1 bias correction produces quantitative fat fraction maps that correlate with T 2 -corrected MRS measurements and show age trends consistent with thymic involution. [ABSTRACT FROM AUTHOR]

Background: Chronic inflammation has been linked to memory and other cognitive impairments, as well as Alzheimer's disease. Here, we investigate the association between inflammatory markers and changes in brain activity measured by regional cerebral blood flow (rCBF) to assess the relationship between inflammation and brain function in older individuals.Methods: Annual 15O water resting-state positron emission tomography (PET) scans collected over a 5-year period were assessed in 138 cognitively normal older participants (77 males; mean age at baseline = 71.3; mean scans per participant = 3.5) in the Baltimore Longitudinal Study of Aging. Voxel-wise linear mixed models were used to investigate associations between rCBF and C-reactive protein (CRP) and interleukin-6 (IL-6) at the time of scanning. We examined relationships between baseline CRP and IL-6 levels and baseline rCBF, and relationships between baseline and mean inflammatory levels over time and longitudinal rCBF changes.Results: Higher baseline CRP and IL-6 were each associated with lower baseline rCBF primarily in frontal and occipital regions, with only the lingual gyrus surviving atrophy correction. Higher baseline and mean CRP were also associated with greater rCBF declines over time in anterior cingulate and hippocampal regions, whereas higher baseline and mean IL-6 levels were associated with greater rCBF declines in orbitofrontal and hippocampal regions.Conclusions: Higher levels of inflammation are associated with longitudinal changes in brain function in regions important for cognition. These results, along with previous studies, suggest that chronic inflammation in older adults may contribute to age-associated declines in cognitive function. [ABSTRACT FROM AUTHOR]

The mechanisms regulating incretin secretion are not fully known. Human obesity is associated with altered incretin secretion and elevated endocannabinoid levels. Since cannabinoid receptors (CBRs) are expressed on incretin-secreting cells in rodents, we hypothesized that endocannabinoids are involved in the regulation of incretin secretion. We compared plasma glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) responses during oral glucose tolerance test (OGTT) in 20 lean and 20 obese participants from the Baltimore Longitudinal Study of Aging (BLSA). Next, we recruited 20 healthy men to evaluate GIP and GLP-1 responses during OGTT after administering placebo or nabilone (CBR agonist) in a randomized, double-blind, crossover fashion. Compared with the BLSA lean group, the BLSA obese group had significantly higher fasting and post-OGTT GIP levels, but similar fasting GLP-1 and significantly lower post-OGTT GLP-1 levels. In the nabilone vs. placebo study, when compared with placebo, nabilone resulted in significantly elevated post-dose fasting GIP levels and post-OGTT GIP levels, but no change in post-dose fasting GLP-1 levels together with significantly lower post-OGTT GLP-1 levels. Glucose levels were not different with both interventions. We conclude that elevated GIP levels in obesity are likely a consequence of increased endocannabinoid levels. CBRs exert tonic control over GIP secretion, which may have a homeostatic effect in suppressing GLP-1 secretion. This raises the possibility that gut hormones are influenced by endocannabinoids. [ABSTRACT FROM AUTHOR]

Whether individuals with insulin resistance (IR) but without criteria for diabetes exhibit reduced mitochondrial oxidative capacity is unclear; addressing this question could guide research for new therapeutics. We investigated 248 participants without diabetes from the Baltimore Longitudinal Study of Aging (BLSA) to determine whether impaired mitochondrial capacity is associated with prediabetes, IR, and duration and severity of hyperglycemia exposure. Mitochondrial capacity was assessed as the postexercise phosphocreatine recovery time constant (τPCr) by 31P-magnetic resonance spectroscopy, with higher τPCr values reflecting reduced capacity. Prediabetes was defined using the American Diabetes Association criteria from fasting and 2-h glucose measurements. IR and sensitivity were calculated using HOMA-IR and Matsuda indices. The duration and severity of hyperglycemia exposure were estimated as the number of years from prediabetes onset and the average oral glucose tolerance test (OGTT) 2-h glucose measurement over previous BLSA visits. Covariates included age, sex, body composition, physical activity, and other confounders. Higher likelihood of prediabetes, higher HOMA-IR, and lower Matsuda index were associated with longer τPCr. Among 205 participants with previous OGTT data, greater severity and longer duration of hyperglycemia were independently associated with longer τPC In conclusion, in individuals without diabetes a more impaired mitochondrial capacity is associated with greater IR and a higher likelihood of prediabetes. [ABSTRACT FROM AUTHOR]

Introduction: Low-calorie sweetener use for weight control has come under increasing scrutiny as obesity, especially abdominal obesity, remain entrenched despite substantial low-calorie sweetener use. We evaluated whether chronic low-calorie sweetener use is a risk factor for abdominal obesity. Participants and Methods: We used 8268 anthropometric measurements and 3096 food diary records with detailed information on low-calorie sweetener consumption in all food products, from 1454 participants (741 men, 713 women) in the Baltimore Longitudinal Study of Aging collected from 1984 to 2012 with median follow-up of 10 years (range: 0–28 years). At baseline, 785 were low-calorie sweetener non-users (51.7% men) and 669 participants were low-calorie sweetener users (50.1% men). Time-varying low-calorie sweetener use was operationalized as the proportion of visits since baseline at which low-calorie sweetener use was reported. We used marginal structural models to determine the association between baseline and time-varying low-calorie sweetener use with longitudinal outcomes—body mass index, waist circumference, obesity and abdominal obesity—with outcome status assessed at the visit following low-calorie sweetener ascertainment to minimize the potential for reverse causality. All models were adjusted for year of visit, age, sex, age by sex interaction, race, current smoking status, dietary intake (caffeine, fructose, protein, carbohydrate, and fat), physical activity, diabetes status, and Dietary Approaches to Stop Hypertension score as confounders. Results: With median follow-up of 10 years, low-calorie sweetener users had 0.80 kg/m2 higher body mass index (95% confidence interval [CI], 0.17–1.44), 2.6 cm larger waist circumference (95% CI, 0.71–4.39), 36.7% higher prevalence (prevalence ratio = 1.37; 95% CI, 1.10–1.69) and 53% higher incidence (hazard ratio = 1.53; 95% CI 1.10–2.12) of abdominal obesity than low-calorie sweetener non-users. Conclusions: Low-calorie sweetener use is independently associated with heavier relative weight, a larger waist, and a higher prevalence and incidence of abdominal obesity suggesting that low-calorie sweetener use may not be an effective means of weight control. [ABSTRACT FROM AUTHOR]

Background: Age-related changes in testosterone levels in older persons and especially in women have not been fully explored. The objective of this study was to describe age-related trajectories of total testosterone (TT), ammonium sulfate precipitation-measured bioavailable testosterone (mBT), and sex hormone-binding glycoprotein (SHBG) in men and women from the Baltimore Longitudinal Study of Aging, with special focus on the oldest adults.Methods: Participants included 788 White men and women aged 30-96 years with excellent representation of old and oldest old, who reported not taking medications known to interfere with testosterone. Longitudinal data were included when available. TT, mBT, and SHBG were assayed. Age-related trajectories of mBT were compared with those obtained using calculated bioavailable testosterone (cBT). Generalized least square models were performed to describe age-related trajectories of TT, mBT, and SHBG in men and women.Results: mBT linearly declines over the life span and even at older ages in both sexes. In men, TT remains quite stable until the age of 70 years and then declines at older ages, whereas in women TT progressively declines in premenopausal years and slightly increases at older ages. Differences in age-related trajectories between total and bioavailable testosterone are only partially explained by age changes in SHBG, whose levels increases at accelerated rates in old persons. Noteworthy, although mBT and cBT highly correlated with one another, mBT is a much stronger correlate of chronological age than cBT.Conclusion: In both men and women, mBT linearly declines over the life span and even at old ages. Its relationship with age-related phenotypes should be further investigated. [ABSTRACT FROM AUTHOR]

Background: Emerging evidence suggests that mildly down-regulated thyroid function in older persons may protect and/or reflect maintained health.Methods: Using observational data collected between January 2006 and March 2014 on a volunteer sample of 602 men and women aged 68-97 years with normal thyroid function participating in the Baltimore Longitudinal Study of Aging, this study examines the concurrent relationship between reported walking ability, usual and rapid gait speed, endurance walk performance, fatigability, and reported energy level with respect to free thyroxine (FT4) within the normal range (0.76-1.50ng/dL) as a continuous variable and categorized as low (lower quartile), medium (interquartile), or high (upper quartile).Results: Adjusting for sex, age, race, height, weight, exercise and smoking, reported walking ability, usual and rapid gait speed, 400-m time, fatigability, and reported energy level were less favorable with increasing FT4 (p = .013 to <.001). In sex-strata, similar associations were observed except for walking ability in men and energy level in women. Categorical analyses revealed that persons with low FT4 exhibited better functional mobility, fitness, and reported energy than persons with intermediate or high levels (p < .05 for all). Persons with high-normal versus medium FT4 had slower usual and rapid gait speed (p < .05) only.Conclusion: Older adults with low-normal FT4 exhibit better mobility, fitness, and fatigue profiles. Mildly down-regulated thyroid function appears to align with better function in old age and may serve as a biomarker of healthy longevity. [ABSTRACT FROM AUTHOR]

Aims: Abdominal fat is a major determinant of metabolic diseases in older individuals. Obesity and diabetes are associated with low serum amylase (SA) levels, but the association between SA and metabolic disease is poorly understood. We investigated the association of low SA with diabetes and sex-specific associations of serum amylase with abdominal fat in older adults.Methods: In community-dwelling volunteers from the Baltimore Longitudinal Study of Aging (778 participants, age 66.8±13.6years), we assessed abdominal fat by computed tomography and diabetes status using the American Diabetes Association criteria. Linear regression analyses assessed the cross-sectional associations between abdominal fat and SA, and logistic regression assessed the odds of diabetes, given low SA.Results: In unadjusted analyses, individuals in the lowest SA quartile (<48μ/L) had 1.97 greater odds of diabetes, (95%CI, 1.01-3.83) than those in the highest quartile (⩾80μ/L). This association was no longer significant after adjusting for visceral adipose tissue area (VAT, dm(2)), abdominal subcutaneous adipose tissue (SAT, dm(2)) or BMI. In adjusted analyses, VAT and SAT were significantly associated with SA in both sexes. Among women, SA was more strongly associated with VAT than with SAT or BMI; VAT (β=-0.117±0.048, P<0.001), SAT (β=-0.023±0.025, P=0.346) and BMI (β=-0.0052±0.075, P=0.49).Conclusions: The association between SA and diabetes was explained mainly by abdominal visceral fat. In women, SA was more strongly associated with VAT than with BMI or SAT. These findings provide motivation for future mechanistic studies on SA's role in metabolic diseases. [ABSTRACT FROM AUTHOR]

Recent reports have shown that cannabinoid 1 receptors (CB1Rs) are expressed in pancreatic β cells, where they induce cell death and cell cycle arrest by directly inhibiting insulin receptor activation. Here, we report that CB1Rs regulate the expression of the anti-apoptotic protein Bcl-2 and cell cycle regulator cyclin D2 in pancreatic β cells. Treatment of MIN6 and βTC6 cells with a synthetic CB1R agonist, WIN55,212–2, led to a decrease in the expression of Bcl-2 and cyclin D2, in turn inducing cell cycle arrest in G0/G1 phase and caspase-3-dependent apoptosis. Additionally, genetic deletion and pharmacological blockade of CB1Rs after injury in mice led to increased levels of Bcl-2 and cyclin D2 in pancreatic β cells. These findings provide evidence for the involvement of Bcl-2 and cyclin D2 mediated by CB1Rs in the regulation of β-cell survival and growth, and will serve as a basis for developing new therapeutic interventions to enhance β-cell function and growth in diabetes. [ABSTRACT FROM AUTHOR]

The cannabinoid 1 receptor (CB1) is an important regulator of energy metabolism. Reports of in vivo and in vitro studies give conflicting results regarding its role in insulin secretion, possibly due to circulatory factors, such as incretins. We hypothesized that this receptor may be a regulator of the entero-insular axis. We found that despite lower food consumption and lower body weight postprandial GLP-1 plasma concentrations were increased in CB1 −/− mice compared to CB1 +/+ mice administered a standard diet or high fat/sugar diet. Upon exogenous GLP-1 treatment, CB1 −/− mice had increased glucose-stimulated insulin secretion. In mouse insulinoma cells, cannabinoids reduced GLP-1R-mediated intracellular cAMP accumulation and subsequent insulin secretion. Importantly, such effects were also evident in human islets, and were prevented by pharmacologic blockade of CB1. Collectively, these findings suggest a novel mechanism in which endocannabinoids are negative modulators of incretin-mediated insulin secretion. [ABSTRACT FROM AUTHOR]

Purpose/Aim: Negative feedback controls in endocrine regulatory systems are well recognized. The incretins and their role in glucose regulation have been of major interest recently. Whether the same negative control system applies to the regulation of incretin secretion is not clear. We sought to examine the hypothesis that exogenous administration of glucagon like peptide-1, GLP-1(7–36) amide or its metabolite GLP-1(9–36) amide, reduces the endogenous basal release of this incretin.Materials and Methods: We evaluated the endogenous basal release of GLP-1 using two separate study designs. In protocol A we examined the GLP-1(7–36) amide levels during the infusion of GLP-1(9–36) amide. In protocol B, we used PYY and GLP-2 as biomarkers for the endogenous basal release of GLP-1(7–36) amide and assessed the endogenous basal release of these two hormones during the GLP-1(7–36) infusion. Twelve lean and 12 obese subjects were enrolled in protocol A and 10 obese volunteers in protocol B.Results: The plasma levels of GLP-1(7–36) amide in protocol A and PYY and GLP-2 in protocol B remained unchanged during the exogenous infusion of GLP-1(9–36) and GLP-1(7–36) amide, respectively.Conclusions: The negative feedback control system as described by inhibition of the release of endogenous hormone while infusing it exogenously was not observed for the basal secretion of GLP-1(7–36) amide. [ABSTRACT FROM PUBLISHER]

R5925 --> 586.3 --> Background: Cellular senescence, one of the hallmarks of aging, refers to a permanent cell cycle arrest and is accelerated during the aging process. A senolytic, a small molecule that eliminates senescent cells, can be a potential strategy to extend healthy lifespan and ameliorate age‐associated diseases. Black ginseng (BG) prepared via nine‐times repetitive steaming and drying process from fresh ginseng (Panax ginsengC.A. Meyer) has been reported to its physiological benefits against reactive oxygen species (ROS), inflammation, and oncogenesis which are common cues to induce aging. Therefore, the present study was aimed to investigate the effect of BG on cellular senescence. Methods: Senescence‐associated β‐galactosidase (SA‐β‐gal) staining was performed on primary mouse embryonic fibroblasts (MEFs) treated 5 μg/mL BG extract for 7 days, and then senescence was induced by γ‐ray irradiation (20 Gy). For animal studies, C57BL/6 male mice were divided into three groups: 9‐week‐old mice orally administered distilled water (Young), 21‐month‐old mice received administration of distilled water (Old), and aged mice supplemented 300 mg/kg BG extracts (Old + BG). After 4 weeks of daily injection, PCR array and immunoblotting were conducted to evaluate mRNA expression and protein levels of targets associated with cellular senescence and cell cycle regulation in metabolic organs, liver, skeletal muscle (SKM), and white adipose tissue (WAT). Results: In in vitro study, BG treatment reduced the density of SA‐β‐gal‐positive MEFs after γ‐ray irradiation (Fig. 1). In aged mice study, BG supplementation remarkedly downregulated age‐related hepatic genes, especially in complement component 1q B (C1qb) and C (C1qc), compared to the aged control group. We further examined the canonical Wnt signaling, augmented in a mouse model of accelerated aging, since the complement C1q family activates Wnt signaling by binding to Frizzled receptors. By assessing the related markers, BG supplementation significantly decreased the hepatic β‐catenin expression level; it also slightly reduced the levels of glycogen synthase kinase 3β (GSK3β) and its phosphorylated form (p‐GSK3β). Recent studies have revealed that Wnt signaling involves in mammalian aging by regulating cell fate and proliferation choice. Thus, we evaluated the expressions of p53 and p21, which involves in cell cycle regulation, and both levels decreased in liver samples from Old + BG group compared to the Old group (Fig. 2). In support of this notion, BG treatment decreased the hepatic mRNA expression levels of senescence‐associated secretory phenotypes (SASPs) such as matrix metallopeptidase 12 (Mmp12) and chemokine ligand 2 (Cxcl2). Consistent with the results in the liver, other metabolic organs, SKM and WAT, showed significantly lower p53 expression in Old + BG group over the Old group. Conclusion: The current study indicates that BG could be a potential candidate of senolytics to reversely regulate cellular senescence, resulting from downregulated complement system affecting Wnt signaling pathways and p53/p21 pathway in metabolic organs. [ABSTRACT FROM AUTHOR]

R5518 --> 583.5 --> Aging is a physiological decrease of several biological activities in an organ that all organisms go through. The presence of a gradual deterioration of cell functioning, due to damage accumulation in metabolic organs, accelerates biological aging. Recently, dietary interventions with food‐active compounds have been linked to suppressing the accumulation of senescent cells and senescence‐associated secretory phenotype (SASP). Curcumin has potent biochemical and biological activities, including antioxidant and anti‐inflammatory actions. However, it largely remains unclear how curcumin has anti‐aging properties such as protection of DNA damage and cell survival/cell fate decisions. The objective of this study is to examine the regulatory effect of dietary curcumin on hepatic cellular senescence in the aged mouse model. Aged (18‐20 months old) male C57BL/6 mice were fed a normal chow diet (NCD) or NCD containing 0.4% (w/w) curcumin ‐ equivalent to 2g/day for a 60 kg adult ‐ (NCD+CUR), high fat high sugar diet (HFHSD) or a HFHSD+CUR (N=7‐9 per group) for 15 weeks. Mice given an HFHSD supplemented with curcumin displayed a different metabolic phenotype compared to mice given an HFHSD alone. To examine the phenotypic plasticity led by transcriptomic alteration, we used RNA‐Seq and analyzed differential gene expression in Gene Ontology (GO) terms and KEGG pathway analysis. There were 1687 and 3794 number of genes that showed a significant change with curcumin in NCD and HFHSD groups compared to their respective control groups. There were at least 8‐fold higher uniquely upregulated and 6‐fold uniquely downregulated genes in the HFHSD+CUR group when compared with their NCD counterparts. To this extent, curcumin supplementation altered hepatic gene expression profiling, especially in senescence pathways and their associated genes. Thus, to validate downregulation in senescence pathway involved genes from the RNA‐Seq data results, we compared the distribution of hepatic senescent cells by β‐gal staining in HFHSD groups. It revealed that HFHSD+CUR mice showed less density of the hepatic senescent cell (Figure A). We then mechanistically sought how curcumin regulates the hepatic senescence pathway. We found that curcumin supplementation decreased senescence effectors, specifically p38 and JNK protein expression levels in the liver (Figure B, C). Our findings suggest that the multifaceted therapeutic potential of curcumin can be used as a protective agent for age‐induced metabolic diseases. [ABSTRACT FROM AUTHOR]

Vismodegib, a highly selective inhibitor of hedgehog ( Hh) pathway, is an approved treatment for basal-cell carcinoma. Patients on treatment with vismodegib often report profound alterations in taste sensation. The cellular mechanisms underlying the alterations have not been studied. Sonic Hh ( Shh) signaling is required for cell growth and differentiation. In taste buds, Shh is exclusively expressed in type IV taste cells, which are undifferentiated basal cells and the precursors of the three types of taste sensing cells. Thus, we investigated if vismodegib has an inhibitory effect on taste cell turnover because of its known effects on Hh signaling. We gavaged C57 BL/6J male mice daily with either vehicle or 30 mg/kg vismodegib for 15 weeks. The gustatory behavior and immunohistochemical profile of taste cells were examined. Vismodegib-treated mice showed decreased growth rate and behavioral responsivity to sweet and bitter stimuli, compared to vehicle-treated mice. We found that vismodegib-treated mice had significant reductions in taste bud size and numbers of taste cells per taste bud. Additionally, vismodegib treatment resulted in decreased numbers of Ki67- and Shh-expressing cells in taste buds. The numbers of phospholipase C β2- and α-gustducin-expressing cells, which contain biochemical machinery for sweet and bitter sensing, were reduced in vismodegib-treated mice. Furthermore, vismodegib treatment resulted in reduction in numbers of T1R3, glucagon-like peptide-1, and glucagon-expressing cells, which are known to modulate sweet taste sensitivity. These results suggest that inhibition of Shh signaling by vismodegib treatment directly results in alteration of taste due to local effects in taste buds. [ABSTRACT FROM AUTHOR]

We have previously demonstrated in human subjects who under euglycemic clamp conditions GLP-1(9–36)amide infusions inhibit endogenous glucose production without substantial insulinotropic effects. An earlier report indicates that GLP-1(9–36)amide is cleaved to a nonapeptide, GLP-1(28–36)amide and a pentapeptide GLP-1(32–36)amide (LVKGR amide). Here we study the effects of the pentapeptide on whole body glucose disposal during hyperglycemic clamp studies. Five dogs underwent indwelling catheterizations. Following recovery, the dogs underwent a 180 min hyperglycemic clamp (basal glucose +98 mg/dl) in a cross-over design. Saline or pentapeptide (30 pmol kg −1 min −1 ) was infused during the last 120 min after commencement of the hyperglycemic clamp in a primed continuous manner. During the last 30 min of the pentapeptide infusion, glucose utilization ( M ) significantly increased to 21.4 ± 2.9 mg kg −1 min −1 compared to M of 14.3 ± 1.1 mg kg −1 min −1 during the saline infusion ( P = 0.026, paired t -test; P = 0.062, Mann–Whitney U test). During this interval, no significant differences in insulin (26.6 ± 3.2 vs. 23.7 ± 2.5 μU/ml, P = NS) or glucagon secretion (34.0 ± 2.1 vs. 31.7 ± 1.8 pg/ml, P = NS) were observed. These findings demonstrate that under hyperglycemic clamp studies the pentapeptide modulates glucose metabolism by a stimulation of whole-body glucose disposal. Further, the findings suggest that the metabolic benefits previously observed during GLP-1(9–36)amide infusions in humans might be due, at least in part, to the metabolic effects of the pentapeptide that is cleaved from the pro-peptide, GLP-1(9–36)amide in the circulation. [ABSTRACT FROM AUTHOR]

Pancreatic polypeptide (PP) is a major agonist for neuropeptide Y4 receptors (NPY4R). While NPY4R has been identified in various tissues, the cells on which it is expressed and its function in those cells has not been clearly delineated. Here we report that NPY4R is present in all somatostatin‐containing cells of tissues that we tested, including pancreatic islets, duodenum, hippocampus, and hypothalamus. Its agonism by PP decreases somatostatin secretion from human islets. Mouse embryonic hippocampal (mHippo E18) cells expressed NPY4Rs and their activation by PP consistently decreased somatostatin secretion. Furthermore, central injection of PP in mice induced c‐Fos immunoreactivity in somatostatin‐containing cells in the hippocampus compared with PBS‐injected mice. In sum, our results identify PP as a pivotal modulator of somatostatin secretion.NPY4Rs were expressed on somatostatin‐containing cells of tissues. PP inhibited somatostatin secretion from human islets and cells. Central injection of PP activated somatostatin‐containing cells in the hippocampus. Our results identify PP as a pivotal modulator of somatostatin secretion. [ABSTRACT FROM AUTHOR]

Summary: Background: Evidence for a role of leptin in depression is limited and conflicting. Inconclusive findings may be explained by the complex effect of obesity on leptin signaling. In particular, both hyperleptinemia due to leptin resistance in obese persons as well as low leptin in lean persons can imply that low leptin biological signaling is associated with an increased risk of significant depressive symptoms. We tested whether the relationship between leptin and depressive symptoms is modulated by abdominal adiposity in two population-based studies. Methods: Data were from 851 participants (65–94 years) of the InCHIANTI Study and 1064 (26–93 years) of the Baltimore Longitudinal Study of Aging (BLSA). Plasma concentrations of leptin, waist circumference and depressive symptoms via the Center for Epidemiological Studies-Depression scale (CES-D) were assessed. In longitudinal InCHIANTI analyses onset of depressed mood (CES-D≥20) was evaluated over a 9-year follow-up. Results: In pooled cross-sectional analyses the interaction between leptin and waist circumference was significantly associated with CES-D scores ((log)leptin-by-waist interaction p =0.01). Also in longitudinal analyses, the (log)leptin-by-waist interaction term significantly (p =0.04) predicted depressed mood onset over time; depressed mood risk was especially increased for high levels of both leptin and waist circumference. Conclusions: The present findings suggest that low leptin signaling rather than low leptin concentration is a risk factor for depression. Future studies should develop proxy measures of leptin signaling by combining information on abdominal adiposity and leptin level to be used for clinical and research applications. [ABSTRACT FROM AUTHOR]

Objectives: Intensive insulin therapy for tight glycemic control in critically ill surgical patients has been shown to reduce mortality; however, intensive insulin therapy is associated with iatrogenic hypoglycemia and increased variability of blood glucose levels. The incretin glucagon-like peptide-1 (7-36) amide is both insulinotropic and insulinomimetic and has been suggested as an adjunct to improve glycemic control in critically ill patients. We hypothesized that the addition of continuous infusion of glucagon-like peptide-1 to intensive insulin therapy would result in better glucose control, reduced requirement of exogenous insulin administration, and fewer hypoglycemic events. Design: Prospective, randomized, double-blind, placebo-controlled clinical trial. Setting: Surgical or burn ICU. Patients: Eighteen patients who required intensive insulin therapy. Interventions: A 72-hour continuous infusion of either glucagon-like peptide-1 (1.5 pmol/kg/min) or normal saline plus intensive insulin therapy. Measurements and Main Results: The glucagon-like peptide-1 cohort (n = 9) and saline cohort (n = 9) were similar in age, Acute Physiology and Chronic Health Evaluation score, and history of diabetes. Blood glucose levels in the glucagon-like peptide-1 group were better controlled with much less variability. The coefficient of variation of blood glucose ranged from 7.2% to 30.4% in the glucagon-like peptide-1 group and from 19.8% to 56.8% in saline group. The mean blood glucose coefficient of variation for the glucagon-like peptide-1 and saline groups was 18.0% ± 2.7% and 30.3% ± 4.0% (p = 0.010), respectively. The 72-hour average insulin infusion rates were 3.37 ± 0.61 and 4.57 ± 1.18 U/hr (p = not significant). The incidents of hypoglycemia (≤ 2.78 mmol/L) in both groups were low (one in the glucagon-like peptide-1 group, three in the saline group). Conclusions: Glucagon-like peptide-1 (7-36) amide is a safe and efficacious form of adjunct therapy in patients with hyperglycemia in the surgical ICU setting. Improved stability of blood glucose is a favorable outcome, which enhances the safety of intensive insulin therapy. Larger studies of this potentially valuable therapy for glycemic control in the ICU are justified. [ABSTRACT FROM AUTHOR]