AMPK α1 mediates the protective effect of adiponectin against insulin resistance in INS-1 pancreatic ß cells.

The fat-derived protein adiponectin is known to reverse the effects of insulin resistance and to lower blood glucose levels. The AMP-activated protein kinase (AMPK) signalling pathway plays a central role in metabolism and energy homeostasis. Here, to investigate the role of AMPK in the protective effect of adiponectin against insulin resistance, we established the model of high-glucose (HG)- and high-lipid (HL)-induced insulin resistance in INS-1 pancreatic ß cells. We found that 25mM of glucose and 0.4mM of palmitic acid treatment significantly increased cell apoptosis and impaired insulin secretion in INS-1 cells. However, recombinant human adiponectin dramatically reduced HG- and/or HL-induced cell apoptosis and greatly improved insulin secretion. Interestingly, adiponectin treatment also activated AMPK signalling pathway by increasing the phosphorylation of Thr172 in the AMPK α subunit; 10µM of compound C, a potent AMPK inhibitor, blocked the protective effects of adiponectin against HG/HL-induced insulin resistance. Furthermore, knockout experiments by CRISPR/Cas9 technology showed that AMPK α1, but not AMPK α2, is involved in the protective effects of adiponectin. Taken together, adiponectin reversed the effects of insulin resistance via AMPK α1, which provides a novel insight into the protective mechanism of adiponectin and may be used as a new strategy for the treatment of type 2 diabetes. SIGNIFICANCE OF THE STUDY: Adiponectin can reverse the effects of insulin resistance and lower blood glucose levels. Here, adiponectin reduced HG/HL-induced cell apoptosis and greatly improved insulin secretion. These effects were blocked by AMPK inhibitor, compound C. Specifically, we found that AMPK α1, but not AMPK α2, mediates the protective effects of adiponectin, which provides a novel insight into the protective mechanism of adiponectin against insulin resistance.

Telmisartan protects against high glucose/high lipid-induced apoptosis and insulin secretion by reducing the oxidative and ER stress.

Telmisartan, an angiotensin II receptor blocker, has been widely used for hypertension. It has also been reported to improve insulin sensitivity in animal models of obesity and diabetic patients by targeting to the peroxisome proliferator-activated receptor (PPAR)-γ. High glucose/high lipid (HG/HL)-induced apoptosis of pancreatic ß-cells impairs its function of insulin secretion and is generally believed to be the key factor in the development of diabetes. In this study, we investigated whether telmisartan exerted a protective effect against HG/HL-induced apoptosis and insulin secretion in vitro as well as in vivo; 10-µM telmisartan treatment significantly reduced HG (25 mM) or/and HL (0.4 mM palmitic acid) induced-cell apoptosis and greatly improved insulin secretion in INS-1 pancreatic ß-cells, which is consistent in an obesity rat model induced by HG/HL diets. Furthermore, telmisartan treatment markedly reduced the protein level of GRP78, CHOP, and caspase 12, while increasing anti-apoptotic Bcl-2 protein expression. Moreover, telmisartan treatment significantly reduced intracellular ROS levels. Mechanistically, we demonstrated that PPARγ signaling pathway may be involved in the telmisartan protective effects, which were blocked by a PPARγ blocker, GW9662. In conclusion, the protective effect of telmisartan was mediated by an anti-ER stress-induced apoptotic and anti-oxidative pathway. SIGNIFICANCE OF THIS STUDY: Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder worldwide pathologically characterized by hyperglycemia and insulin resistance. Long-term high glucose in the blood has been proposed to induce pancreatic ß-cell loss and is generally believed to be the key factor in the development of diabetes. In the present study, we demonstrated that telmisartan, a common drug used for hypertension treatment, has a protective effect against high glucose/high lipid-induced cell apoptosis and greatly improves the insulin secretion function by inhibiting the oxidative stress and ER stress. Furthermore, this protective effect of telmisartan is mediated by the PPAR-γ signal pathway, which may provide a potential strategy against T2DM.

Telmisartan Improves Insulin Resistance: A Meta-Analysis.

BACKGROUND: Diabetes mellitus, metabolic syndrome, and other obesity-related diseases are characterized by insulin resistance (IR) as a common pathophysiological change and are closely related to cardiovascular disease, which seriously threaten human health. Telmisartan belongs to a group of drugs called angiotensin II receptor antagonists (ARBs) and it can partially activate peroxisome proliferator-activated receptors. Animal experiments have confirmed that telmisartan can regulate glucose and lipid metabolism, and improve IR. STUDY QUESTION: This study performs a systematic review of the advantages of telmisartan in improving IR and compared it with other ARBs. STUDY DESIGN: Randomized controlled trials (RCTs) that compared telmisartan with other ARBs in patients with obesity, diabetes, impaired glucose tolerance, and metabolic syndrome were searched from PubMed, EMBASE, the Cochrane Library, China National Knowledge Infrastructure, Wan Fang Database, and Chinese biomedical literature database (CBM). RCTs published as of the end of April 2017 were included in the present study. MEASURES AND OUTCOMES: The outcomes included homeostasis model assessment of insulin resistance, fasting blood glucose level, fasting insulin level, diastolic blood pressure, and systolic blood pressure. We used a fixed-effects model or random-effects model to pool the estimates according to the heterogeneity between the included studies. RESULTS: A total of 21 RCTs, which included 1679 patients, were included. Results revealed that telmisartan was superior in improving homeostasis model assessment of insulin resistance (mean difference = -0.23, 95% confidence interval [CI], -0.40 to -0.06), reducing fasting blood glucose level (mean difference = -0.32, 95% CI, -0.57 to -0.07), reducing fasting insulin level (mean difference = -1.01, 95% CI, -1.63 to -0.39), and decreasing diastolic blood pressure (mean difference = -1.46, 95% CI, -2.10 to -0.82) compared with other ARBs. However, for the decrease in systolic pressure, the difference was not statistically significant (mean difference = -0.73, 95% CI, -1.53 to 0.07). CONCLUSION: Telmisartan can better improve IR compared with other ARBs.

[Nilotinib treatment for patients with imatinib-resistant or intolerant chronic myeloid leukemia].

This study was purposed to evaluate the efficacy and safety of nilotinib for treating patients with imatinib-resistant or intolerant chronic myeloid leukemia (CML). A total of 23 patients with imatinib-resistant or intolerant CML were enrolled in this study. These patients received nilotinib orally 600-800 mg every day, their curative efficacy, tolerance and overal survival were evaluated. The results showed that all the patients treated with nilotinib obtained complete hematologic remission (CHR), out of them 82.6% patients achieved complete cytogenetic remission (CCyR) and 56.5% patients achieved complete molecular remission (CMR), their adverse events mostly were mild to moderate, generally were transient and easily cured; the median treatment time with nilotinib was 13.5 (1-44) months, and the median follow-up time was 40 (12-102) months. It is concluded that nilotinib has been confirmed to be effective for patients with imatinib-resistant or intolerant CML, and may be selected as a second generation of tyrosine kinase inhibitor (TKI).