Exendin-4 Promotes Beta Cell Proliferation via PI3k/Akt Signalling Pathway.

BACKGROUND/AIMS: Prevention of diabetes requires maintenance of a functional beta-cell mass, the postnatal growth of which depends on beta cell proliferation. Past studies have shown evidence of an effect of an incretin analogue, Exendin-4, in promoting beta cell proliferation, whereas the underlying molecular mechanisms are not completely understood. METHODS: Here we studied the effects of Exendin-4 on beta cell proliferation in vitro and in vivo through analysing BrdU-incorporated beta cells. We also analysed the effects of Exendin-4 on beta cell mass in vivo, and on beta cell number in vitro. Then, we applied specific inhibitors of different signalling pathways and analysed their effects on Exendin-4-induced beta cell proliferation. RESULTS: Exendin-4 increased beta cell proliferation in vitro and in vivo, resulting in significant increases in beta cell mass and beta cell number, respectively. Inhibition of PI3K/Akt signalling, but not inhibition of either ERK/MAPK pathway, or JNK pathway, significantly abolished the effects of Exendin-4 in promoting beta cell proliferation. CONCLUSION: Exendin-4 promotes beta cell proliferation via PI3k/Akt signaling pathway.

The Integrated Bioinformatic Assay of Genetic Expression Features and Analyses of Traditional Chinese Medicine Specific Constitution Reveal Metabolic Characteristics and Targets in Steatosis of Nonalcoholic Fatty Liver Disease.

Purpose: In this study, our primary aim is to analyze the genetic expression feature and analyze specific Traditional Chinese medicine (TCM) constitution distribution in non-alcoholic fatty liver disease (NAFLD) and reveal the metabolic characteristic of NAFLD. Materials and Methods: For revealing genetic features, we obtained the gene expression data from the Gene Expression Omnibus (GEO) database of the National Center for Biotechnology Information (NCBI). The genetic data on NAFLD were analyzed by identifying differentially expressed genes (DEGs), associated pathways, co-expressed genetic networks, and gene set enrichment function. Concurrently, we assessed specific constitution distributions among local NAFLD patients through established TCM constitution models and determined the independent variable, including specific constitution to the NAFLD via the regression analyses. Results: The analyses on GEO datasets showed that simple steatosis in NAFLD is strongly associated with HOMA-insulin resistance (HOMA-IR). Analyses of GEO datasets revealed significantly altered genetic expression profiles between NAFLD and normal populations. For TCM constitution analyses, we demonstrated a decline in yin-yang harmony (YYH) and yang-asthenia (YAAC) constitution, whereas there was an increase in qi-stagnation (QSC) and phlegm-dampness (PDC) in NAFLD. The binary logistic regression analysis indicated that besides other metabolic parameters, YYH, qi asthenia (QAC), YYAC, and yin-asthenia (YAC) were the independent variables of NAFLD, while YAC was the independent variables of T2D. The multilinear regression analyses suggested that NAFLD, DM, BMI, waist, TC, TG, hypertension, ALT, AST, and YAC were the significant determinators of the FPG. Conclusion: This study presents a relatively comprehensive metabolic profile in steatosis of NAFLD, revealed by significant genetic expression feature alterations and different TCM constitution distribution in NAFLD. Through this method, the study intends to associate the genetic feature with the phenotype of TCM constitution. The results could be applied to assist integrative medicine research in exploring the appropriate personalized approaches for NAFLD.

Long-Term Prognosis of Different Subtypes of Left Ventricular Noncompaction Cardiomyopathy Patients: A Retrospective Study in China.

Left ventricular noncompaction (LVNC) is a heterogeneous cardiomyopathy that can be classified into different subtypes based on morphologic and functional features. However, the prognosis of the dilated and isolated subtypes of non-pediatric LVNC remains unknown. We retrospectively studied 101 patients with LVNC diagnosed at Peking Union Medical College Hospital from 2006 to 2022 using the Jenni criteria of transthoracic echocardiography. The patients were grouped into those with dilated LVNC (n = 64) or isolated LVNC (n = 37), and 88 patients (54 with dilated LVNC and 34 with isolated LVNC) were followed up successfully. The primary outcome was major adverse cardiovascular events (a composite of cardiovascular mortality, heart failure, severe ventricular arrhythmia, and systolic embolism). The median follow-up time was 5.24 years. The incidence of major adverse cardiovascular events was 43.2%; patients with dilated LVNC had a higher risk (adjusted hazard ratio, 4.43; 95% confidence interval, 1.24-15.81; p = 0.02) than those with isolated LVNC. None of the isolated LVNC patients had cardiovascular deaths or severe ventricular arrhythmias. The risk of systemic embolism was similar between patients with dilated and isolated LVNC. Our findings indicate that transthoracic echocardiography is a useful tool for classifying LVNC into subtypes with distinct clinical outcomes. Dilated LVNC is associated with a poor prognosis, while the isolated subtype is probably a physiological condition.

Effect of exercise on the expression of adiponectin mRNA and GLUT4 mRNA in type 2 diabetic rats.

To investigate the impact of exercise on the expression of adiponectin and GLUT4 mRNA in type 2 diabetic rats, type 2 diabetic rat model was made. The diabetic rats were treated with swimming training for 8 weeks. The expression of adiponectin mRNA in perirenal fat and GLUT4 mRNA in skeletal muscles were assessed by reverse transcription polymerase chain reaction (RT-PCR) and the levels of blood glucose, serum insulin, and blood lipid were measured. Our results showed that the expression of adiponectin mRNA and GLUT4 mRNA in diabetic model group was decreased by 45% (P < 0.01), 43% (P < 0.01) respectively. The gene expression of adiponectin and GLUT4 was increased significantly in swimming group (P < 0.05 and P < 0.01, respectively). Compared with the model group, fasting insulin, TG, TC and FFA were decreased significantly in the training group (P < 0.05 or P < 0.01) as compared with model group. It is concluded that exercise can promote the expression of adiponectin mRNA and GLUT4 mRNA in type 2 diabetic rats, which may be one of the mechanisms responsible for the amelioration of insulin resistance in the rats.

Astragalus polysaccharides affect insulin resistance by regulating the hepatic SIRT1-PGC-1α/PPARα-FGF21 signaling pathway in male Sprague Dawley rats undergoing catch-up growth.

The present study investigated the effects of Astragalus polysaccharides (APS) on insulin resistance by modulation of hepatic sirtuin 1 (SIRT1)­peroxisome proliferator­activated receptor (PPAR)­Î³ coactivator (PGC)­1α/PPARα­fibroblast growth factor (FGF)21, and glucose and lipid metabolism. Thirty male Sprague Dawley rats were divided into three groups: A normal control group, a catch­up growth group and an APS­treated (APS-G) group. The latter two groups underwent food restriction for 4 weeks, prior to being provided with a high fat diet, which was available ad libitum. The APS­G group was orally treated with APS for 8 weeks, whereas the other groups were administered saline. Body weight was measured and an oral glucose tolerance test (OGTT) was conducted after 8 weeks. The plasma glucose and insulin levels obtained from the OGTT were assayed, and hepatic morphology was observed by light and transmission electron microscopy. In addition, the mRNA expression levels of PGC­1α/PPARα, and the protein expression levels of SIRT1, FGF21 and nuclear factor­κB were quantified in the liver and serum. APS treatment suppressed abnormal glycolipid metabolism and insulin resistance following 8 weeks of catch­up growth by improving hepatic SIRT1­PPARα­FGF21 intracellular signaling and reducing chronic inflammation, and by partially attenuating hepatic steatosis. The suppressive effects of APS on liver acetylation and glycolipid metabolism­associated molecules contributed to the observed suppression of insulin resistance. However, the mechanism underlying the effects of APS on insulin resistance requires further research in order to be elucidated. Rapid and long­term treatment with APS may provide a novel, safe and effective therapeutic strategy for type 2 diabetes.