Project description:IntroductionFasting glucose increases with age and is linked to modifiable Alzheimer's disease risk factors such as cardiovascular disease and Type 2 diabetes (T2D).MethodsWe leveraged available biospecimens and neuroimaging measures collected during the Alzheimer's Prevention Through Exercise (APEx) trial (n = 105) to examine the longitudinal relationship between change in blood glucose metabolism and change in regional cerebral amyloid deposition and gray and white matter (WM) neurodegeneration in older adults over 1 year of follow-up.ResultsIndividuals with improving fasting glucose (n = 61) exhibited less atrophy and regional amyloid accumulation compared to those whose fasting glucose worsened over 1 year (n = 44). Specifically, while individuals with increasing fasting glucose did not yet show cognitive decline, they did have regional atrophy in the hippocampus and inferior parietal cortex, and increased amyloid accumulation in the precuneus cortex. Signs of early dementia pathology occurred in the absence of significant group differences in insulin or body composition, and was not modified by apolipoprotein E ε4 carrier status.DiscussionDysregulation of glucose in late life may signal preclinical brain change prior to clinically relevant cognitive decline. Additional work is needed to determine whether treatments specifically targeting fasting glucose levels may impact change in brain structure or cerebral amyloid in older adults.
Project description:ObjectiveEvidence regarding the relationship between the hepatic steatosis index (HSI) and glycemic conversion outcomes in individuals with impaired fasting glucose (IFG) is still limited. Our study aims to explore the role of HSI in the reversion to normoglycemia or the progression to diabetes among Chinese IFG individuals.MethodsWe conducted a retrospective analysis using data from 11,327 IFG individuals who had undergone wellness examinations at Rich Healthcare Group. To analyze the association between the baseline HSI and glucose status conversion, a Cox regression model was used, and the hazard ratio (HR) and 95% confidence interval (CI) were computed. A generalized additive model was used to examine non-linear relationships. A two-piecewise binary logistic regression model was employed to further elucidate the non-linearity. Sensitivity and subgroup analyses were also conducted.ResultsOver an observation period spanning 33,892 person-years, the rate of normoglycemia reversion was found to be 41.75%, whereas the rate of progression to diabetes was 11.63%. After accounting for potential confounding variables, our analysis demonstrated that among IFG individuals, there was an inverse relationship between HSI and the likelihood of returning to normoglycemia (HR = 0.93, 95% CI: 0.90-0.96, P < 0.001), and a positive association between the HSI and progression to diabetes (HR = 1.49, 95% CI: 1.40-1.58, P < 0.001). The smooth curve-fitting plot revealed a nonlinear association between the HSI and diabetes progression, with inflection points at 26.55 and 40.74. Sensitivity analysis and subgroup analysis confirmed the stability of the study's findings.ConclusionHSI was significantly linked to normoglycemia reversion and diabetes progression in IFG individuals, indicating its potential as a risk indicator for diabetes and a guide for prevention strategies. However, further research is needed to confirm this.
Project description:The hepatic steatosis index (HSI) has been demonstrated to have a significant correlation with prediabetes and diabetes; however, its potential association with reversion to normal glucose regulation (NGR) from prediabetes remains insufficiently investigated. The primary objective of this study was to elucidate the relationship between HSI levels and the probability of reversion to NGR among Chinese adults with prediabetes. This retrospective cohort study utilized health examination data from 11,241 Chinese adults with prediabetes. Cox proportional hazard models were employed to calculate hazard ratios (HR) and 95% confidence intervals (CI) to assess the association between HSI levels and reversion to NGR. Additionally, a Cox proportional hazards regression model incorporating cubic spline functions and smooth curve fitting was utilized to determine any nonlinear relationships between HSI levels and reversion to NGR. The results of the multivariate analyses demonstrated a significant association between reduced HSI levels and an increased likelihood of reversion to NGR (HR = 0.92, 95%CI: 0.89-0.95, P < 0.0001). Furthermore, a nonlinear relationship was identified between HSI levels and the reversion to NGR, with a critical threshold at an HSI value of 43.08. Below this threshold, a strong negative association was observed, markedly enhancing the probability of returning to normoglycemic status (HR = 0.91, 95% CI: 0.88-0.94, P < 0.0001). This study reveals a negative, nonlinear correlation between HSI levels and the reversion to NGR in individuals with prediabetes. These findings highlight the essential role of effectively managing HSI as part of comprehensive prediabetes treatment strategies, which may significantly enhance the likelihood of achieving normoglycemic status.
Project description:Estrogens are known to play a role in modulating metabolic processes within the body. The Aromatase knockout (ArKO) mice have been shown to harbor factors of Metabolic syndrome with central adiposity, hyperinsulinemia and male-specific hepatic steatosis. To determine the effects of estrogen ablation and subsequent replacement in males on whole body glucose metabolism, three- and six-month-old male ArKO mice were subjected to whole body glucose, insulin and pyruvate tolerance tests and analyzed for ensuing metabolic changes in liver, adipose tissue, and skeletal muscle. Estrogen-deficient male ArKO mice showed increased gonadal adiposity which was significantly reduced upon 17β-estradiol (E2) treatment. Concurrently, elevated ArKO serum leptin levels were significantly reduced upon E2 treatment and lowered serum adiponectin levels were restored to wild type levels. Three-month-old male ArKO mice were hyperglycemic, and both glucose and pyruvate intolerant. These phenotypes continued through to 6 months of age, highlighting a loss of glycemic control. ArKO livers displayed changes in gluconeogenic enzyme expression, and in insulin signaling pathways upon E2 treatment. Liver triglycerides were increased in the ArKO males only after 6 months of age, which could be reversed by E2 treatment. No differences were observed in insulin-stimulated ex vivo muscle glucose uptake nor changes in ArKO adipose tissue and muscle insulin signaling pathways. Therefore, we conclude that male ArKO mice develop hepatic glucose intolerance by the age of 3 months which precedes the sex-specific development of hepatic steatosis. This can be reversed upon the administration of exogenous E2.
Project description:Endocrine disrupting chemicals (EDCs) include non-persistent exogenous substances such as parabens, bisphenols and phthalates which have been associated with a range of metabolic disorders and disease. It is unclear if exposure remains consistent over time. We investigated change in indicators of EDC exposure between 2009 and 2016 and assessed its consistency between and within individuals over a median follow-up time of 47 months in a sample of Dutch individuals. Of 500 Dutch individuals, two 24 h urine samples were analysed for 5 parabens, 3 bisphenols and 13 metabolites of in total 8 different phthalates. We calculated per-year differences using meta-analysis and assessed temporal correlations between and within individuals using Spearman correlation coefficients, intra-class correlation coefficients (ICC) and kappa-statistics. We found a secular decrease in concentrations of methyl, ethyl, propyl and n-butyl paraben, bisphenol A, and metabolites of di-ethyl phthalate (DEP), di-butyl phthalate (DBP), di-(2-ethyl-hexyl) phthalate (DEHP), and butylbenzyl phthalate (DBzP) which varied from 8 to 96% (ethyl paraben, propyl paraben) between 2009 and 2016. Within-person temporal correlations were highest for parabens (ICC: 0.34 to 0.40) and poorest for bisphenols (ICC: 0.15 to 0.23). For phthalate metabolites, correlations decreased most between time periods (ICC < 48 months: 0.22 to 0.39; ≥48 months: 0.05 to 0.32). When categorizing EDC concentrations, 33-54% of individuals remained in the lowest or highest category and temporal correlations were similar to continuous measurements. Exposure to most EDCs decreased between 2009 and 2016 in a sample of individuals with impaired fasting glucose from the Dutch population. Temporal consistency was generally poor. The inconsistency in disease associations may be influenced by individual-level or temporal variation exhibited by EDCs. Our findings call for the need for repeated measurements of EDCs in observational studies before and during at-risk temporal windows for the disease.
Project description:Clozapine is an atypical antipsychotic with therapeutic efficacy in treatment-resistant schizophrenia patients and low incidence of extrapyramidal side effects. However, the use of clozapine has been limited by its adverse effects on metabolism. Artesunate is a semisynthetic derivative of artemisinin and was shown to decrease the plasma cholesterol and triglyceride in rabbits and rats in recent studies. The aim of this study was to examine possible effects of artesunate on the clozapine-induced metabolic alterations in rats given saline, clozapine, artesunate, or clozapine plus artesunate for 6 weeks. The clozapine group showed significantly high plasma levels of triglyceride, hepatic steatosis, and fibrosis along with high levels of C-reactive protein, alanine aminotransferase, and aspartate aminotransferase compared to the saline group. But the treatment had no effect on weight gain and caused no hyperglycemia, hyperinsulinemia, and behavioral changes in the rats. More significantly, these clozapine-induced changes were not seen in rats coadministered with clozapine plus artesunate. These results added evidence supporting psychiatrists to try add-on treatment of artesunate in schizophrenia patients to ameliorate clozapine-induced adverse metabolic effects.
Project description:In the fasted state, induction of hepatic glucose output and fatty acid oxidation is essential to sustain energetic balance. Production and oxidation of glucose and fatty acids by the liver are controlled through a complex network of transcriptional regulators. Among them, the transcriptional coactivator PGC-1alpha plays an important role in hepatic and systemic glucose and lipid metabolism. We have previously demonstrated that sirtuin 1 (SIRT1) regulates genes involved in gluconeogenesis through interaction and deacetylation of PGC-1alpha. Here, we show in vivo that hepatic SIRT1 is a factor in systemic and hepatic glucose, lipid, and cholesterol homeostasis. Knockdown of SIRT1 in liver caused mild hypoglycemia, increased systemic glucose and insulin sensitivity, and decreased glucose production. SIRT1 knockdown also decreased serum cholesterol and increased hepatic free fatty acid and cholesterol content. These metabolic phenotypes caused by SIRT1 knockdown tightly correlated with decreased expression of gluconeogenic, fatty acid oxidation and cholesterol degradation as well as efflux genes. Additionally, overexpression of SIRT1 reversed many of the changes caused by SIRT1 knockdown and depended on the presence of PGC-1alpha. Interestingly, most of the effects of SIRT1 were only apparent in the fasted state. Our results indicate that hepatic SIRT1 is an important factor in the regulation of glucose and lipid metabolism in response to nutrient deprivation. As these pathways are dysregulated in metabolic diseases, SIRT1 may be a potential therapeutic target to control hyperglycemia and hypercholesterolemia.
Project description:Nuclear receptor Pregnane X Receptor (PXR; NR1I2) has transcriptional regulation functions for energy homeostasis in the liver. Mouse PXR has a conserved phosphorylation motif at serine 347 (serine 350 in humans) within the ligand-binding domain. PXR phosphorylated at this motif is expressed in mouse livers in response to fasting. Mice with a PXR∗Ser347Ala knockin mutation (PXR KI) were generated to block phosphorylation, and utilized to investigate the role of Ser347 phosphorylation in vivo. PXR KI mice had decreased body weight at 8-weeks of age and had much greater weight loss after fasting compared with PXR WT mice. The cDNA microarray analysis of hepatic mRNAs showed that cell death or apoptotic signaling was induced in fasting PXR KI mice. Moreover, increasing hepatic lipids, triglycerides and the development of hypertriglyceridemia were observed in fasting PXR KI mice. These findings are indicative that blocking phosphorylation prevents mice from maintaining hepatic energy homeostasis. Thus, phosphorylated PXR may be an essential factor to prevent the liver from developing damage caused by fasting.
Project description:With the increasing prevalence of type 2 diabetes and fatty liver disease, there is still an unmet need to better treat hyperglycemia and hyperlipidemia. Here, we identify isthmin-1 (Ism1) as an adipokine and one that has a dual role in increasing adipose glucose uptake while suppressing hepatic lipid synthesis. Ism1 ablation results in impaired glucose tolerance, reduced adipose glucose uptake, and reduced insulin sensitivity, demonstrating an endogenous function for Ism1 in glucose regulation. Mechanistically, Ism1 activates a PI3K-AKT signaling pathway independently of the insulin and insulin-like growth factor receptors. Notably, while the glucoregulatory function is shared with insulin, Ism1 counteracts lipid accumulation in the liver by switching hepatocytes from a lipogenic to a protein synthesis state. Furthermore, therapeutic dosing of recombinant Ism1 improves diabetes in diet-induced obese mice and ameliorates hepatic steatosis in a diet-induced fatty liver mouse model. These findings uncover an unexpected, bioactive protein hormone that might have simultaneous therapeutic potential for diabetes and fatty liver disease.
Project description:Hepatic glucose production (HGP) is crucial for glucose homeostasis, but the underlying mechanisms have not been fully elucidated. Here, we show that a calcium-sensing enzyme, CaMKII, is activated in a calcium- and IP3R-dependent manner by cAMP and glucagon in primary hepatocytes and by glucagon and fasting in vivo. Genetic deficiency or inhibition of CaMKII blocks nuclear translocation of FoxO1 by affecting its phosphorylation, impairs fasting- and glucagon/cAMP-induced glycogenolysis and gluconeogenesis, and lowers blood glucose levels, while constitutively active CaMKII has the opposite effects. Importantly, the suppressive effect of CaMKII deficiency on glucose metabolism is abrogated by transduction with constitutively nuclear FoxO1, indicating that the effect of CaMKII deficiency requires nuclear exclusion of FoxO1. This same pathway is also involved in excessive HGP in the setting of obesity. These results reveal a calcium-mediated signaling pathway involved in FoxO1 nuclear localization and hepatic glucose homeostasis.