Liraglutide combined with human umbilical cord mesenchymal stem cell transplantation inhibits beta-cell apoptosis via mediating the ASK1/JNK/BAX pathway in rats with type 2 diabetes.

OBJECTIVE: Accumulating evidence suggests an association between beta-cell apoptosis and the ASK1/JNK/BAX pathway. The aim of this study was to investigate the effects of a combined therapy of liraglutide and human umbilical cord mesenchymal stem cells (hUC-MSCs) on the glucose metabolism and islet beta-cell apoptosis, and further explore its relationship to the ASK1/JNK/BAX pathway. METHOD: Type 2 diabetes mellitus (T2DM) rat model was induced by a high-sugar and high-fat diet and intraperitoneal injection of low-dose streptozotocin (STZ) (30 mg/kg). Three days after STZ injection, diabetic rats were randomly treated with subcutaneous injection of liraglutide (200 µg/kg/12 h) for 8 weeks and or hUC-MSCs (1 × 106 /rat) at the first and fifth weeks. Diabetes-related physical and biochemical parameters, pancreatic histopathological changes, immunohistochemical staining, quantitative real-time polymerase chain reaction, and western blot were used to measure the expression of apoptosis signal-regulating kinase 1 (ASK1), Jun N-terminal kinase (JNK), Bcl-2 associated X protein (BAX), and B-cell lymphoma-2 (Bcl-2). RESULTS: Eight weeks after liraglutide or human umbilical cord mesenchymal stem cell administration, FPG, HbA1c , glucagon, body weight, and pancreatic ASK1, JNK, and BAX mRNA and proteins were significantly decreased, and the levels of serum C-p, INS and GLP-1, ratio of insulin positive area, and Bcl-2 expression were significantly increased in three treatment groups compared with T2DM group (P<.05). CONCLUSION: Liraglutide combined with hUC-MSCs improve glucose metabolism and inhibit islet beta-cell apoptosis in a ASK1/JNK/BAX pathway-dependent manner.

[The design and baseline characteristics of a phase III study to evaluate the efficacy and safety of alogliptin versus placebo in type 2 diabetes mellitus in Mainland China].

OBJECTIVE: To assess the design and the Mainland China subgroup baseline characteristics of the study to evaluate the efficacy and safety of alogliptin versus placebo in subjects with type 2 diabetes (T2DM) as monotherapy, add-on to metformin or add-on to pioglitazone. METHODS: This was a multi-center, randomized, double-blind, placebo-controlled, 16-week study comparing alogliptin (ALO, 25 mg, 1/d) versus placebo (PLA) as monotherapy (A), add-on to metformin (B) or add-on to pioglitazone ± metformin (C). The T2DM subjects with glycosylated hemoglobin A1c(HbA1c) between 7% and 10% and aged between 18 years and 75 years were enrolled and randomized to the alogliptin group and the placebo group in 1: 1 ratio with 16 weeks treatment. All patients were followed up every 4 weeks. The safety endpoints consisted of the incidence of hypoglycemia and other adverse events. RESULTS: A total of 491 patients were enrolled in the Mainland China subgroup of the study (181 in group A, 186 in group B and 124 in group C). In each treatment group, the baseline characteristics including age, gender, body mass index, diabetes duration, HbA1c, fasting plasma glucose, body weight, daily dosage of metformin and daily dosage of pioglitazone were all well balanced. CONCLUSION: The demographic data, medical history, glycemic profile and treatment regimen at baseline in Mainland China subgroup are well balanced. The result of this study will provide the clinical evidence for the use of alogliptin in Chinese T2DM patients.

[Effects of quercetin on nuclear factor-κB p65 expression in renal ubiquitin-proteasome system of diabetic rats].

OBJECTIVE: To investigate the protective effect of quercetin on diabetic nephropathy and to explore its possible mechanism. METHODS: Type 2 diabetes mellitus rat model was established by feeding high-carbohydrate-fat diet and injecting with streptozotocin. At 72 hour after injection, blood samples were collected from the tail veins of all rats. Those rats with blood glucose level ≥ 16.7 mmol/L were considered as the diabetes model been successfully established. The model rats were randomly divided into type 2 diabetic group (group DM, n = 9) and quercetin group (group QUE, n = 9). Other rats were used as normal controls (group NC, n = 8). All rats were performed by intragastric administration for 8 weeks. At the end of experiment, the rats were sacrificed and fasting plasma glucose (FPG), fasting insulin(FIns), serum creatinine (SCr), blood urea nitrogen (BUN), TG, TC, LDL-C, 24 h urine protein (24 h UP), and kidney index (KI) were evaluated. Pathological changes of kidney were observed by periodic acid-silver methenamine (PASM). The expressions of ubiquitin and NF-κB p65 on glomeruli were examined by immunohistochemical method, and its association with the incidence of proteinuria was analyzed. RESULTS: In groups DM and QUE, the level of FPG [(25.45 ± 1.23) mmol/L and (19.99 ± 1.20) mmol/L], FIns [(25.67 ± 2.58) mU/L and (19.29 ± 1.80) mU/L], SCr [(44.00 ± 2.53) µmol/L and (34.43 ± 2.23) µmol/L], BUN[(11.60 ± 0.39) mmol/L and (8.20 ± 0.37) mmol/L], TG[(3.32 ± 0.22)mmol/L and (2.43 ± 0.25) mmol/L], TC [(2.95 ± 0.21) mmol/L and (2.24 ± 0.17) mmol/L], LDL-C [(2.03 ± 0.22) mmol/L and (1.49 ± 0.13) mmol/L], 24 h UP[(46.67 ± 2.50) mg/24 h and (25.57 ± 2.82) mg/24 h] and KI [(9.76 ± 0.30)×10³ and (8.44 ± 0.26)×10³] were significantly increased than the indexes of group NC [(6.56 ± 0.41) mmol/L, (12.63 ± 1.41) mU/L, (22.88 ± 2.36) µmol/L, (5.45 ± 0.51) mmol/L, (1.64 ± 0.11) mmol/L, (1.33 ± 0.17) mmol/L, (0.46 ± 0.05) mmol/L, (12.38 ± 1.19)/24 h and (6.78 ± 0.12)×10³]. Moreover, the above indexes in group QUE were obviously lower than group DM. There was evidence of pathological changes associated with diabetes, such as focal and segmental sclerosis and thickened basement and mesangial expansion. The expressions of ubiquitin and NF-κB p65 in renal tissues of group DM increased significantly (P < 0.01). The expression of ubiquitin and NF-κB p65 were positively related with the level of 24 h UP (r = 0.893, 0.879, P < 0.01). Compared with group DM, all above indexes in group QUE were markedly alleviated (P < 0.01). The expression of ubiquitin and NF-κB p65 was reduced but didn't reach level in group NC (P < 0.01). CONCLUSION: The increased expression of NF-κB induced by ubiquitin-proteasome system may participate in the pathogenesis of proteinuria in diabetic nephropathy. Quercetin has renal protective effects partly through reducing NF-κB p65 expression.

Antiproliferation of cardamonin is involved in mTOR on aortic smooth muscle cells in high fructose-induced insulin resistance rats.

The objective of this study was to determine possible effects and potential mechanisms of cardamonin on improving insulin resistance and vascular proliferative lesions in the rat's model system. Fed with 60% fructose-enriched diet for 12 weeks, male Sprague-Dawley (SD) rats developed insulin resistance and hyperinsulinemia. They also showed excessive proliferation of the vascular smooth muscle cells (VSMCs) and activation of the mammalian target of rapamycin (mTOR)/translation control proteins p70 ribosomal S6 kinase (P70S6K1)/eukaryotic initiation factor 4E binding protein 1 (4E-BP1) signaling in the rat thoracic aorta. From weeks 9-12, cardamonin was injected into the peritoneal cavity once daily. Under the detection of microscopy and electron microscopy, cardamonin improved hyperinsulinemia and inhibited proliferation of VSMCs in the thoracic aorta of rats in a dose-dependent manner. By the Real-Time RT-PCR, mRNA expression of mTOR, P70S6K1 and 4E-BP1 was significantly reduced in cardamonin treated rats. Similarly, protein over-expression of mTOR and p-P70S6K1 was obviously inhibited by immunohistochemical analyses. These findings suggest that cardamonin may play a role in ameliorating insulin resistance and smooth muscle hyperplasia of major vessels in fructose-induced rats, possibly via a mechanism that involves the modulation of insulin/mTOR signaling.