Metformin is a widely used antidiabetic drug for type 2 diabetes that can play a cardioprotective role through multiple pathways. It is a recognized agonist of AMP-activated protein kinase (AMPK) that blocks mitochondrial complex I. The NLRP3 inflammasome has been demonstrated to be activated in diabetic cardiomyopathy (DCM). However, the role of metformin in regulating the NLRP3 signaling pathway in DCM remains unclear. It has been reported that AMPK can inhibit NLRP3 by activating autophagy. The aim of this study was to investigate whether metformin can inhibit the NLRP3 inflammasome by activating the AMPK/mTOR pathway in DCM. In this study, streptozotocin-induced C57BL/6 mice and high glucose-treated primary cardiomyocytes from neonatal mice were treated with metformin or an AMPK inhibitor compound C. Echocardiography, hematoxylin-eosin and Masson staining showed that the function and morphology of the diabetic hearts were improved after metformin treatment, whereas these parameters deteriorated after intervention with an AMPK inhibitor. Immunohistochemical staining, immunofluorescence staining and western blot assays indicated that the expression levels of mTOR, NLRP3, caspase-1, IL-1β and GSDMD-N were decreased in the diabetic model treated with metformin and were reversed after the administration of an AMPK inhibitor in vivo and in vitro . Mechanistically, our results demonstrated that metformin can activate AMPK, thus improving autophagy via inhibiting the mTOR pathway and alleviating pyroptosis in DCM. Thus, we provide novel information for the treatment of DCM.

Non-: alcoholic fatty liver disease (NAFLD) is prevalent worldwide, especially in patients with type 2 diabetes. Liver enzymes are the main warning signs of liver injury and insulin resistance (IR) is critical to NAFLD. This study was aimed to investigate the association between liver enzymes and insulin resistance in type 2 diabetes patients with NAFLD. Data from 212 diabetes patients with NAFLD were analyzed, including 118 males and 94 females who received care from 2014 to 2015. The patients were divided into three groups by severity (mild n=87, moderate n=89, severe n=36). All patients underwent standard clinical and laboratory examinations. Liver enzymes including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and γ-glutamyl transferase (GGT) were measured, serum fasting glucose and serum fasting insulin were obtained. IR was assessed using the homeostasis model assessment insulin resistance index (HOMA-IR). Age, sex, and BMI did not significantly differ in patients (p>0.05). Compared with normal levels, elevated ALT and AST were associated with a higher HOMA-IR (p=0.0035, p=0.0096, respectively). HOMA-IR did not significantly differ (p>0.05) between patients with normal and elevated GGT. HOMA-IR increased as the levels of liver enzymes increased, and each enzyme showed a significant association with HOMA-IR (p=0.0166, p<0.0001, and p <0.0001). HOMA-IR differs between normal and elevated ALT and AST. Liver enzymes are associated with HOMA-IR in type 2 diabetes patients with NAFLD. These findings can help evaluate the degree of IR and hepatocellular steatosis in patients and prevent the progression of type 2 diabetes and NAFLD in clinical practice.

Diabetic cardiomyopathy (DCM) is the leading cause of morbidity and mortality in diabetes mellitus (DM) patients. Previous studies have shown that the transforming growth factor-beta 1 (TGF-b1)/Smad signaling pathway plays a key role in the development of myocardial fibrosis in DCM. Silymarin (SMN) is used clinically to treat liver disorders and acts by influencing TGF-b1. However, the possible effects of silymarin on DCM remain to be elucidated. In our study, the DM animal model was induced by streptozotocin (STZ) injection. Fasting blood glucose level was measured, and the structure and function of the heart were measured by hematoxylin and eosin (H&E) and Masson staining, echocardiography, and transmission electron microscopy (TEM). Western blot was used to detect the expression of TGF-b1, Smad2/3, phosphorylation Smad2/3(p-Smad2/ 3), and Smad7. Our results showed that silymarin downregulated blood glucose level and significantly improved cardiac fibrosis and collagen deposition in DM rats detected by H&E, Masson staining, and TEM assays. The echocardiography results showed that silymarin administration attenuated cardiac dysfunction in DM rats. Additionally, compared with untreated DM rats, levels of TGF-b1 and p-Smad2/3 were decreased, whereas Smad7 was increased following silymarin administration. These data demonstrate that silymarin ameliorates DCM through the inhibition of TGF-b1/Smad signaling, suggesting that silymarin may be a potential target for DCM treatment.

Patients with type 2 diabetes mellitus (T2DM) are usually with poor immunity and easier to suffer from cancer and microbial infections. Herein, we report an efficient anti-diabetic medicinal mushroom, Coriolus versicolor (CV). This study aimed to investigate the anti-diabetic and anti-insulin-resistance effects of CV aqueous extract in myoblasts (L6 cells) and skeletal muscle of T2DM rat. Our results showed that CV extract treatment significantly reduced blood glucose levels of T2DM rats, whereas CV extract increased glucose consumption in insulin resistant L6 cells. Besides, the translocation and expression of glucose transporter 4 were enhanced by CV extract, which indicated that CV extract was effective in diabetic skeletal muscle. Moreover, CV extract treatments resulted in remarkable anti-insulin-resistance effects, which was reflected by the change of gene and protein expression levels in PI3K/Akt and p38 MAPK pathways. PI3K inhibitor, LY29004, and p38 MAPK inhibitor, SB203580 confirmed it further. In conclusion, our results demonstrated that the CV extract exhibited anti-diabetic and anti-insulin-resistance effects in diabetic skeletal muscle, and the effects were mediated by PI3K/Akt and p38 MAPK pathways. These findings are remarkable when considering the use of commercially available CV by diabetic patients who also suffer from cancer or microbial infections.