stilbenes and Prediabetic-State

Sirt1 and 5' adenosine monophosphate-activated protein kinase (AMPK) are energy-sensing systems that work cooperatively and regulate mitochondrial biogenesis and fuel metabolism, and mediate, in part, the salutary effects of caloric restriction on lifespan and healthspan. We have shown that leucine activates Sirt1 and enables synergy with sirtuin co-activators. Resveratrol is a widely recognized activator of Sirt1; however, poor bioavailability and rapid metabolism limit effective clinical translation of promising animal data. However, we found that combining low resveratrol doses with leucine increased skeletal muscle and adipocyte Sirt1 activity, mitochondrial biogenesis and fatty acid oxidation; these effects result in increased lifespan and marked reductions in insulin resistance, inflammatory markers, body weight, and visceral adiposity in preclinical models. To translate these data to humans, we assessed the effects of resveratrol (50 mg)/leucine (1.11 g) on glucose dynamics in a 4-week placebo-controlled trial of 36 prediabetic subjects. Leucine-resveratrol reduced insulin resistance (homeostatic model assessment for insulin resistance) 33% with corresponding reductions in glucose and insulin area under the curve in oral glucose tolerance tests. We extended these concepts in preclinical studies using both direct Sirt1 activators and Sirt1 pathway activators. Low-dose (10 nM) NAD

Topics: AMP-Activated Protein Kinases; Animals; Humans; Insulin Resistance; Leucine; Longevity; Mice, Obese; Prediabetic State; Resveratrol; Sirtuin 1; Stilbenes

2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG) is an active compound derived from Polygonum multiflorum Thunb., a Chinese Taoist herbal medicine, which exerts lipid lowering, anti-cancer, anti-aging, anti-inflammatory and hepatoprotective effects. However, its role in protecting hepatocytes under pre-diabetic condition remains unclear.. In this study, we developed prediabetic SD rats by feeding high-fat and high-sugar diet. The body weight, blood lipid, blood glucose, and fasting insulin (FINS) and insulin resistance index (HOMA-IR) were detected and calculated to assess the potential risk of prediabetes. HE and Oil Red O staining was used, and blood level of biochemical index was detected to observe the liver injury. The autophagic cell death-associated signaling proteins, and the potential signaling factors p-Akt/Akt and p-Erk/Erk were detected using western blot to explore the potential effects of TSG on pre-diabetic liver and the underlying mechanisms.. The results showed that the body weight in TSG-treated group was significantly decreased vs. the model group. The blood glucose, the level of FINS and HOMA-IR, TC and TG were decreased in TSG-treated group as well. Furthermore, TSG treatment significantly ameliorated lipid droplet accumulation, enhanced liver anti-oxidative response which may be associated with an increased activity of SOD and GSH-Px, and a decrease of LDLC and MDA. The autophagic cell death-associated proteins, p-AMPK, ATG12, LC3 II, and Beclin 1 were up-regulated in the TSG-treated group, while the upstream signaling pathway, PI3K/Akt and Erk, were activated.. TSG induced liver autophagic cell death to protect liver from prediabetic injury by activating PI3K/Akt and Erk.

Topics: Animals; Autophagy; Fallopia multiflora; Glucosides; Liver; Male; MAP Kinase Signaling System; Molecular Structure; Phosphatidylinositol 3-Kinases; Prediabetic State; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Stilbenes

Hyperglycaemia in diabetes is either caused by reduced availability of insulin (type 1 diabetes, T1D) or insulin resistance to the cells (type 2 diabetes, T2D). In recent years, the prevalence of T2D has increased to an alarming proportion, encompassing 95 percent of the total diabetic burden, probably due to economy-driven changes in lifestyle. Recent epidemiological studies show comorbid depression, anxiety and related mental illness. To explore the molecular mechanisms underlying this comorbid conditions, we used Sprague-Dawley rats on high-fructose diet for 8 weeks to induce prediabetic condition. Rats with this metabolic syndrome also showed hyper-anxiety when they were subjected to anxiety-related behavioural assays. Rats were administered with resveratrol, an activator of sirtuins, and metformin, a standard antidiabetic drug, simultaneously with fructose. We observed that resveratrol was more effective in protecting from both the metabolic (prediabetic) and affective (anxiety) disorders than metformin. Molecular studies showed that recovery was associated with the upregulation of few nuclear sirtuins that act epigenetically - Sirt 1 and 7, which were significantly attenuated in the striatum of prediabetic rats. In conclusion, our study showed that hyper-anxiety associated with prediabetic condition is ameliorated by resveratrol through modulation of sirtuins, which is more or less similar to metformin.

Topics: Animals; Antioxidants; Anxiety Disorders; Blood Glucose; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diet; Epigenesis, Genetic; Fructose; Gene Expression Regulation; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Metformin; Prediabetic State; Rats; Resveratrol; Sirtuin 1; Sirtuins; Stilbenes

This study aims to determine whether pterostilbene improves glycaemic control in rats showing insulin resistance induced by an obesogenic diet. Rats were divided into 3 groups: the control group and two groups treated with either 15 mg kg(-1) d(-1) (PT15) or 30 mg kg(-1) d(-1) of pterostilbene (PT30). HOMA-IR was decreased in both pterostilbene-treated groups, but this reduction was greater in the PT15 group (-45% and -22% respectively vs. the control group). The improvement of glycaemic control was not due to a delipidating effect of pterostilbene on skeletal muscle. In contrast, GLUT4 protein expression was increased (+58% and +52% vs. the control group), suggesting an improved glucose uptake. The phosphorylated-Akt/total Akt ratio was significantly enhanced in the PT30 group (+25%), and therefore a more efficient translocation of GLUT4 is likely. Additionally, in this group the amount of cardiotrophin-1 was significantly increased (+65%). These data suggest that the effect of pterostilbene on Akt is mediated by this cytokine. In the liver, glucokinase activity was significantly increased only in the PT15 group (+34%), and no changes were observed in glucose-6-phosphatase activity. The beneficial effect of pterostilbene on glycaemic control was more evident with the lower dose, probably because in the PT15 group both the muscle and the liver were contributing to this effect, but in the PT30 group only the skeletal muscle was responsible. In conclusion, pterostilbene improves glycaemic control in rats showing insulin resistance induced by an obesogenic diet. An increase in hepatic glucokinase activity, as well as in skeletal muscle glucose uptake, seems to be involved in the anti-diabetic effect of this phenolic compound.

Topics: Animals; Cytokines; Diet, High-Fat; Dietary Sucrose; Dietary Supplements; Glucokinase; Glucose Transporter Type 4; Hypoglycemic Agents; Insulin Resistance; Liver; Male; Muscle, Skeletal; Obesity; Organ Specificity; Phosphorylation; Prediabetic State; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-akt; Random Allocation; Rats, Wistar; Stilbenes; Up-Regulation