Anti-diabetic potential of apigenin,luteolin,and baicalein via partially activating PI3K/Akt/GLUT-4 signaling pathways in insulin-resistant HepG2 cells

Dietary flavonoids are abundant in natural plants and possess multiple pharmacological and nutritional activities.In this study,apigenin,luteolin,and baicalein were chosen to evaluate their anti-diabetic effect in high-glucose and dexamethasone induced insulin-resistant(IR)HepG2 cells.All flavonoids improves the glucose consumption and glycogen synthesis abilities in IR-HepG2 cells via activating glucose transporter protein 4(GLUT4)and phosphor-glycogen synthase kinase(GSK-3β).These fl avonoids signifi cantly inhibited the production of reactive oxygen species(ROS)and advanced glycation end-products(AGEs),which were closely related to the suppression of the phosphorylation form of NF-κB and P65.The expression levels of insulin receptor substrate-1(IRS-1),insulin receptor substrate-2(IRS-2)and phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)pathway in IR-HepG2 cells were all partially activated by the fl avonoids,with variable effects.Furthermore,the intracellular metabolic conditions of the fl avonoids were also evaluated.

Angiotensin-receptor blockers as therapy for mild-to-moderate hypertension-associated non-alcoholic steatohepatitis

AIM： TO evaluate insulin resistance, cytolysis and nonalcoholic steatohepatitis （NASH） score （NAS） using the Kleiner and Brunt criteria in 54 patients with NASH and mild-to-moderate hypertension, treated with telmisartan vs valsartan for 20 mo. METHODS： All patients met the NCEP-ATP Ⅲ criteria for metabolic syndrome. Histology confirmed steatohepatitis, defined as a NAS greater than five up to 3 wk prior inclusion, using the current criteria. Patients with viral hepatitis, chronic alcohol intake, drug abuse or other significant immune or metabolic hepatic pathology were excluded. Subjects were randomly assigned either to the valsartan （V） group （standard dose 80 mg o.d., n = 26）, or to the telmisartan （T） group （standard dose 20 mg o.d., n = 28）. Treatment had to be taken daily at the same hour with no concomitant medication or alcohol consumption allowed. Neither the patient nor the medical staff was aware of treatment group allocation. Paired liver biopsies obtained at inclusion （visit 1） and end of treatment （EOT） were assessed by a single blinded pathologist, not aware of patient or treatment group. Blood pressure, BMI, ALT, AST, HOMA-IR, plasma triglycerides （TG） and total cholesterol （TC） were evaluated at inclusion and every 4 mo until EOT （visit 6）. RESULTS： At EOT we noticed a significant decrease in ALT levels vs inclusion in all patients and this decrease did not differ significantly in group T vs group V. HOMA-IR significantly decreased at EOT vs inclusion in all patients but in group T, the mean HOMA-IR decrease per month was higher than in group V. NAS significantly diminished at EOT in all patients with a higher decrease in group T vs group V. CONCLUSION： Angiotensin receptor blockers seem to be efficient in hypertension-associated NASH. Telmisartan showed a higher efficacy regarding insulin resistance and histology, perhaps because of its specific PPAR-gamma ligand effect.

Post-transplant diabetes mellitus and preexisting liver disease-a bidirectional relationship affecting treatment and management

Liver cirrhosis and diabetes mellitus(DM)are both common conditions with significant socioeconomic burden and impact on morbidity and mortality.A bidirectional relationship exists between DM and liver cirrhosis regarding both etiology and disease-related complications.Type 2 DM(T2DM)is a wellrecognized risk factor for chronic liver disease and vice-versa,DM may develop as a complication of cirrhosis,irrespective of its etiology.Liver transplantation(LT)represents an important treatment option for patients with end-stage liver disease due to non-alcoholic fatty liver disease(NAFLD),which represents a hepatic manifestation of metabolic syndrome and a common complication of T2DM.The metabolic risk factors including immunosuppressive drugs,can contribute to persistent or de novo development of DM and NAFLD after LT.T2DM,obesity,cardiovascular morbidities and renal impairment,frequently associated with metabolic syndrome and NAFLD,may have negative impact on short and long-term outcomes following LT.The treatment of DM in the context of chronic liver disease and post-transplant is challenging,but new emerging therapies such as glucagon-like peptide-1 receptor agonists(GLP-1RAs)and sodium–glucose cotransporter 2 inhibitors(SGLT2i)targeting multiple mechanisms in the shared pathophysiology of disorders such as oxidative stress and chronic inflammation are a promising tool in future patient management.

Renal gluconeogenesis in insulin resistance:A culprit for hyperglycemia in diabetes

Renal gluconeogenesis is one of the major pathways for endogenous glucose production.Impairment in this process may contribute to hyperglycemia in cases with insulin resistance and diabetes.We reviewed pertinent studies to elucidate the role of renal gluconeogenesis regulation in insulin resistance and diabetes.A consensus on the suppressive effect of insulin on kidney gluconeogenesis has started to build up.Insulin-resistant models exhibit reduced insulin receptor(IR)expression and/or post-receptor signaling in their kidney tissue.Reduced IR expression or post-receptor signaling can cause impairment in insulin’s action on kidneys,which may increase renal gluconeogenesis in the state of insulin resistance.It is now established that the kidney contributes up to 20%of all glucose production via gluconeogenesis in the post-absorptive phase.However,the rate of renal glucose release excessively increases in diabetes.The rise in renal glucose release in diabetes may contribute to fasting hyperglycemia and increased postprandial glucose levels.Enhanced glucose release by the kidneys and renal expression of the gluconeogenic-enzyme in diabetic rodents and humans further point towards the significance of renal gluconeogenesis.Overall,the available literature suggests that impairment in renal gluconeogenesis in an insulinresistant state may contribute to hyperglycemia in type 2 diabetes.

Exercise intervention under hypoxic condition as a new therapeutic paradigm for type 2 diabetes mellitus:A narrative review

This review aims to summarize the health benefits of exposure to hypoxic conditions during exercise in patients with type 2 diabetes mellitus(T2 DM).Exposure to hypoxic conditions during exercise training positively changes the physiological response in healthy subjects.Exposure to hypoxic conditions during exercise could markedly increase skeletal muscle glucose uptake compared to that in normoxic conditions.Furthermore,post-exercise insulin sensitivity of T2 DM patients increases more when exercising under hypoxic than under normoxic conditions.Regular exercise under short-term hypoxic conditions can improve blood glucose control at lower workloads than in normoxic conditions.Additionally,exercise training under short-term hypoxic conditions can maximize weight loss in overweight and obese patients.Previous studies on healthy subjects have reported that regular exercise under hypoxic conditions had a more positive effect on vascular health than exercising under normoxic conditions.However,currently,evidence indicating that exposure to hypoxic conditions could positively affect T2 DM patients in the long-term is lacking.Therefore,further evaluations of the beneficial effects of exercise under hypoxic conditions on the human body,considering different cycle lengths,duration of exposures,sessions per day,and the number of days,are necessary.In this review,we conclude that there is evidence that exercise under hypoxic conditions can yield health benefits,which is potentially valuable in terms of clinical care as a new intervention for T2 DM patients.

High-Lard and High-Fish Oil Diets Differ in Their Effects on Insulin Resistance Development, Mitochondrial Morphology and Dynamic Behaviour in Rat Skeletal Muscle

Fish oil (mainly omega 3 polyunsaturated fatty acids), differently from lard (mainly saturated fatty acids) has been suggested to have anti-inflammatory effects associated with amelioration of insulin sensibility. An important role in skeletal muscle insulin resistance development has been recently attributed to mitochondrial dynamic behavior. Mitochondria are dynamic organelles that frequently undergo fission/fusion processes and a shift toward fission process has been associated with skeletal muscle mitochondrial dysfunction and insulin resistance development. The present work aimed to evaluate if the replacement of lard with fish oil in high-fat diet positively affect skeletal muscle mitochondrial dynamic behavior in association with the improvement of insulin-resistance. Body weight gain, systemic insulin-resistance (glucose/insulin ratio), serum TNFα levels and skeletal muscle lipid content were assessed in rats fed a high-lard or high-fish-oil diet for 6 weeks. In skeletal muscle sections, immunohistochemical analysis were performed to detect the presence of insulin receptor substrate 1 (IRS1) and tyrosine phosphorylated IRS1 (key factor in insulin signalling pathway) as well as to detect the main proteins involved in mitochondrial fusion (MFN2 and OPA1) and fission (DRP1 and Fis1) processes. Skeletal muscle mitochondrial ultrastructural features were assessed by electron microscopy. High-fish oil feeding induced lower body weight gain, systemic inflammation and insulin-resistance development as well as skeletal muscle lipid accumulation compared to high-lard feeding. Skeletal muscle sections from high-fish oil fed rats exhibited a greater number of immunoreactive fibers for MFN2 and OPA1 proteins as well as weaker immunostaining for DRP1 and Fis1 compared to sections from high-lard fed rats. Electron microscopy observations suggested a prominent presence of fission events in L rats and fusion events in F rats. The positive effect of the replacement of lard with fish oil in high-fat diet on systemic and skeletal muscle insulin sensibility was associated to changes in mitochondrial dynamic behavior.

Responsibility of hepatitis C virus in the development of hepatocellular carcinoma:From molecular alterations to possible solutions

There are several causes of hepatocellular carcinoma(HCC), but certainly the hepatitis C virus(HCV) is one of the most common. The HCV is able to contribute, both directly and indirectly, to the development of HCC. Determining early HCV clearance before an advanced liver disease develops, is absolutely necessary as this prevents the initiation of the cascade of events induced by HCV that may result in the development of HCC. The early treatment of the infection and the clearance of HCV represents today, in the age of the direct antiviral agents(DAAs), an extraordinary opportunity for true prevention of the development of HCV-related HCC.

Bis(acetylacetonato)-oxidovanadium(Ⅳ) inhibits isoproterenol-induced lipolysis in insulin-resistant 3T3-L1 adipocytes by reducing phosphorylation of perilipin and hormone-sensitive lipase

Insulin resistance is characterized as one of crucial pathological changes in type 2 diabetes mellitus（T2DM）, and dyslipidaemia is frequently detected in T2DM. A variety of vanadium compounds have been studied as drug candidates for diabetes based on their insulin-like action. However, few studies focus on their antilipolytic effect. In the present study, we established an insulin-resistant model in 3T3-L1 adipocytes to mimic pathological conditions of T2DM according to a well-established method by the treatment of high concentrations of glucose and insulin, which was validated by oil red O staining and the decreased levels of phosphorylated Akt, AS160 and GSK3 after insulin treatment. The results demonstrated that bis（acetylacetonato）-oxidovanadium（Ⅳ）（VO（acac）_2） could inhibit isoproterenol-stimulated lipolysis through the reduction of the phosphorylated HSL and perilipin levels in both insulin-sensitive and insulin-resistant 3T3-L1 adipocytes. Moreover, although the levels of phosphorylated Akt induced by VO（acac）_2 were decreased, the rates of lipolytic inhibition were not significantly altered compared with those under insulin-sensitive condition, indicating that the anti-lipolytic effect of VO（acac）_2 might also function in an Akt-independent way in insulin-resistant adipocytes. Our work here help elucidate the anti-diabetic effects of vanadium compounds. It may not only shed light on the utility of vanadium-based compounds as potential anti-diabetic drugs but also serve as a useful screening model for new anti-diabetic drugs.

Muscle mass loss and intermuscular lipid accumulation were associated with insulin resistance in patients receiving hemodialysis

Background An accelerated muscle wasting was the pivotal factor for protein-energy wasting in end stage renal disease. However, very few researches have examined the skeletal muscle quantity and quality in clinical patients. This study investigated the muscle morphologic changes by magnetic resonance imaging （MRI） and analyzed the related factors in hemodialysis patients. Methods Fifty-eight patients receiving maintenance hemodialysis （HD） were investigated and 28 healthy adults with gender and age matched were used as controls （Control）. Anthropometry, cytokine factors, and laboratory data were measured. The muscle and intermuscular adipose tissues （IMAT） were analyzed via a Thigh MRI. The bicep samples were observed after HE staining. Homeostatic model assessment of insulin resistance （HOMA-IR） was measured and their association with muscle wasting was analyzed. Results HD patients tended to have a lower protein diet, anthropometry data, and serum albumin, but the C reactive protein and interleukin-6 increased significantly. The MRI showed that HD patients had less muscle mass and a lower muscle/total ratio, but the fat/muscle and IMAT was higher when compared to the Control group. The muscle fiber showed atrophy and fat accumulation in the biceps samples come from the HD patients. Moreover, we found that the HD patients presented with a high level of plasma fasting insulin and increased HOMA-IR which negatively correlated with the muscle/ total ratio, but positively with the fat/muscle ratio. Conclusions Muscle wasting presented early before an obvious malnutrition condition emerged in HD patients. The main morphological change was muscle atrophy along with intermuscular lipid accumulation. Insulin resistance was associated with muscle wasting in dialysis patients.