Enhanced insulin-stimulated glycogen synthesis in response to insulin, metformin or rosiglitazone is associated with increased mRNA expression of GLUT4 and peroxisomal proliferator activator receptor gamma co-activator 1

Aims/hypothesis The aim of this study was to determine the effect of several antidiabetic agents on insulin-stimulated glycogen synthesis, as well as on mRNA expression.Methods Cultured primary human skeletal myotubes obtained from six healthy subjects were treated for 4 or 8 days without or with glucose (25 mmol/l), insulin (400 pmol/l), rosiglitazone (10 mol/l), metformin (20 mol/l) or the AMP-activated kinase activator 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) (200 mol/l). After this, insulin-stimulated glycogen synthesis was determined. mRNA levels of the glucose transporters GLUT1 and GLUT4, the peroxisomal proliferator activator receptor gamma (PPAR gamma) co-activator 1 (PGC1) and the myocyte-specific enhancer factors (MEF2), MEF2A, MEF2C and MEF2D were determined using real-time PCR analysis after 8 days exposure to the various antidiabetic agents.Results Insulin-stimulated glycogen synthesis was significantly increased in cultured human myotubes treated with insulin, rosiglitazone or metformin for 8 days, compared with non-treated cells. Furthermore, an 8-day exposure of myotubes to 25 mmol/l glucose impaired insulin-stimulated glycogen synthesis. In contrast, treatment with AICAR was without effect on insulin-mediated glycogen synthesis. Exposure to insulin, rosiglitazone or metformin increased mRNA expression of PGC1 and GLUT4, while AICAR or 25 mmol/l glucose treatment increased GLUT1 mRNA expression. Metformin also increased mRNA expression of the MEF2 isoforms.Conclusions/interpretation Enhanced insulin-stimulated glycogen synthesis in human skeletal muscle cell culture coincides with increased GLUT4 and PGC1 mRNA expression following treatment with various antidiabetic agents. These data show that chronic treatment of human myotubes with insulin, metformin or rosiglitazone has a direct positive effect on insulin action and mRNA expression.     

水飞蓟素联合二甲双胍治疗肥胖型非酒精性脂肪肝疗效分析

目的分析水飞蓟素联合二甲双胍对肥胖型非酒精性脂肪肝患者的治疗作用。方法符合诊断标准的肥胖型非酒精性脂肪肝患者48例分为两组，试验组24例联合水飞蓟素及二甲双胍治疗，对照组24例服用水飞蓟素及维生素C片治疗，疗程均为4～6月。治疗前后测定各组患者血清转氨酶水平（ALT、AST）、血脂水平（TG、TC、LDL-C及HDL-C）、血清TNFα水平、胰岛素抵抗指数（IRI）及肝／脾CT比值并作统计学处理，同时观察实验过程中出现的不良反应。结果治疗后两组患者血清ALT均明显降低，其中尤以试验组降低明显（P〈0．01）；试验组患者治疗后各项血脂水平均显著改善；试验组胰岛素抵抗指数于治疗后明显下降（P〈0．05），而对照组无明显改变（P〉0．05）；两组患者治疗后血清TNFα均明显下降，尤以试验组下降明显（P〈0．01）；同时试验组治疗后肝／脾CT比值显著升高（P〈0．01）。用药期间两组患者均未出现显著不良反应。结论水飞蓟素联合二甲双胍对肥胖型非酒精性脂肪肝有显著疗效且用药安全。     

Metformin enhances certain insulin actions in cultured rat hepatoma cells

Summary The effect of the oral antidiabetic agent metformin on insulin regulation of glycogen metabolism, tyrosine-aminotransferase activity, and [1-¹⁴C]aminoisobutyric acid uptake was studied in H4IIE cultured rat hepatoma cells. Metformin enhanced both basal (from 0.213±0.016 to 0.262±0.024 nmol/mg protein,p<0.01) and insulin stimulated [³H] glucose incorporation into glycogen in a time-dependent and dose-dependent manner. A small effect of metformin was seen at 1 μmol/l, and its greatest effects were obtained at 10 μmol/l. At the same concentrations, metformin did not influence basal tyrosine-aminotransferase activity but it potentiated insulin stimulated tyrosine-aminotransferase activity (+ 29.2±1.4%,p<0.01) and prevented the loss of tyrosine-aminotransferase responsiveness to insulin in H4IIE cells desensitised by a previous exposure to insulin. In contrast, metformin had no effect on basal or insulin-stimulated [1-¹⁴C]aminoisobutyric acid uptake. Over the concentrations of metformin that enhanced insulin action in H4IIE cells, the drug had no significant effect on insulin binding to its receptor. These studies suggest, therefore, that metformin may influence cellular metabolism by potentiating certain insulin actions through mechanisms that may be beyond insulin receptor binding.     

Effect of plasma metformin concentrations on serum lipid levels in type II diabetic patients

Summary In this study we evaluated the relationships between plasma metformin levels, measured by reversed-phase high-performance liquid chromatography, and serum lipid levels in 20 metformintreated, type II diabetic patients. Mean fasting plasma metformin concentration was 490 ± 188 ng/ml. No correlation was found between daily dose of drug and lipid parameters. A significant correlation emerged between circulating metformin concentration and serum triglycerides (r=−0.574, p<0.01), HDL-cholesterol (r=0.583, p<0.01) and HDL₂-cholesterol (r=0.670, p<0.05). Multiple linear regression analysis showed that the correlation between plasma metformin concentration and serum triglycerides still remained significant after correction for other clinical and metabolic parameters. Total cholesterol and HDL₃-cholesterol were not correlated with metformin concentrations. These results demonstrate the clinical usefulness of measuring plasma metforminc concentrations and indicate that some effects of metformin on lipid metabolism depend on the drug plasma levels.     

达格列净联合利拉鲁肽治疗2型糖尿病的临床研究

目的 探究达格列净联合利拉鲁肽治疗2型糖尿病患者的临床效果。方法 收集2017年1月—2019年4月在郑州人民医院治疗的2型糖尿病患者126例,随机分为对照组（63例）和治疗组（63例）。对照组口服盐酸二甲双胍片,0.5 g/次,3次/d,同时于睡前皮下注射利拉鲁肽注射液0.6 mg,1周后根据患者肠道反应增加至1.2 mg,1次/d。治疗组早餐前口服达格列净片,10 mg/次,1次/d;利拉鲁肽注射液的用法同对照组。两组患者治疗时间均为3个月。观察两组患者临床疗效,同时比较治疗前后两组患者糖化血红蛋白（HbA1c）、空腹血糖（FPG）、餐后2 h血糖（2 h PG）、体质量指数（BMI）、白细胞介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）、对纤溶酶原激活物抑制物-1（PAI-1）和胱抑素C（CysC）水平。结果 治疗后,对照组和治疗组临床有效率分别为79.37%和93.65%,两组比较差异有统计学意义（P<0.05）。治疗后,两组患者HbA1c、FPG、2 h PG、BMI、IL-6、TNF-α、PAI-1、CysC均显著降低（P<0.05）,且治疗组上述指标比对照组更低（P<0.05）。结论 达格列净联合利拉鲁肽治疗2型糖尿病患者效果显著,且不增加不良反应,降低发生糖尿病血管并发症的风险。     

联合沙格列汀与二甲双胍治疗2型糖尿病的临床疗效分析

目的探讨二甲双胍联合沙格列汀治疗2型糖尿病效果。方法96例糖尿病患者随机分为二甲双胍组、联合用药组各48例,二甲双胍组给二甲双胍,0.5 g,tid,po;联合用药组另加沙格列汀片,5mg,qd,po。结果治疗6个月以后,联合用药组空腹血糖(FBG)(6.01±0.97)mol/L、餐后2 h血糖(2hPBG)(8.53±1.22)mol/L、糖化血红蛋白HbAlc(6.94±0.88)%、体重指数(BMI)(24.47±1.09)kg/m^2低于二甲双胍组的(7.42±1.04)mol/L、(9.28±1.34)mol/L、(7.14±0.97)%、(25.82±1.22)kg/m^2(P<0.05);总有效率95.83%高于二甲双胍组83.33%(P<0.05)。结论联合沙格列汀与二甲双胍治疗2型糖尿病,显著降低FBG、2hPBG、HbAlc、BMI,提高治疗总有效率。     

格列美脲联合二甲双胍对老年糖尿病的治疗作用研究

目的探讨格列美脲联合二甲双胍对老年糖尿病的治疗作用。方法100例老年糖尿病患者,随机分为二甲双胍组与格列美脲联合二甲双胍组,各50例。二甲双胍组患者采取二甲双胍治疗,格列美脲联合二甲双胍组采取格列美脲联合二甲双胍治疗。比较两组疗效;空腹、餐后血糖达标时间和糖化血红蛋白降低至<6%时间;治疗前后患者血糖、血脂;不良反应发生率。结果格列美脲联合二甲双胍组总有效率为100.00%,高于二甲双胍组的82.00%,差异有统计学意义(P<0.05)。治疗后,格列美脲联合二甲双胍组患者的餐后2 h血糖、空腹血糖、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)均低于二甲双胍组,差异有统计学意义(P<0.05)。格列美脲联合二甲双胍组空腹、餐后血糖达标时间和糖化血红蛋白降低至<6%时间均短于二甲双胍组,差异有统计学意义(P<0.05)。格列美脲联合二甲双胍组用药期间出现腹泻症状1例(2.00%);二甲双胍组用药期间出现腹泻症状1例(2.00%),两组不良反应发生率比较,差异无统计学意义(P>0.05)。结论格列美脲联合二甲双胍治疗老年糖尿病效果确切,可有效改善血糖和血脂,且无明显不良反应,安全性高。     

二甲双胍与美沙拉嗪在小鼠结肠炎中的疗效比较

目的 探讨二甲双胍与美沙拉嗪在治疗小鼠结肠炎中的疗效差异性。方法 选取6 ~ 8周龄的C57BL/6雄性小鼠32只,随机分为Control组、硫酸葡聚糖（DSS）组、DSS+美沙拉嗪组、DSS+二甲双胍组,每组8只。Control组小鼠自由饮用高压灭菌双蒸水,并每日予0.2 ml 磷酸盐缓冲液（PBS）灌胃。采用3%DSS诱导C57BL/6雄性小鼠结肠炎模型。DSS组小鼠自由饮用3%DSS溶液,每日予0.2 ml PBS灌胃,DSS+美沙拉嗪组、DSS+二甲双胍组自由饮用3%DSS溶液,予100 mg/（kg·d） 的美沙拉嗪或100 mg/（kg·d） 二甲双胍灌胃。评估各组小鼠体质量变化、结肠长度、疾病活动指数、组织病理学改变及肠道炎症因子表达情况。结果 与DSS组相比,DSS+二甲双胍与DSS+美沙拉嗪组均可降低小鼠结肠炎所致的体质量丢失、疾病活动度评分、组织病理学评分及肠道炎症因子表达水平（P均< 0.05）,但DSS+二甲双胍组与DSS+美沙拉嗪组上述指标比较差异均无统计学意义（P均> 0.05）。结论 二甲双胍可以减轻DSS诱导的小鼠结肠炎,其疗效不亚于美沙拉嗪。     

Specific interpretation of hair concentrations in 2 fatal metformin intoxication cases

Hair analysis is very useful for toxicological investigations since, by providing a wider detection window, it gives the possibility to perform a retrospective study on the historical consumption of a substance. Unfortunately, there are no data available for hair concentrations in metformin-related deaths. In this study, the authors present 2 cases of fatal metformin intoxication in which, for the first time, hair analysis was performed using a specific GC–MS/MS method. Metformin was tested positive in femoral blood (112.3 mg/L and 64.7 mg/L respectively) and cardiac blood (226.9 and 203.2 mg/L) of the two subjects. For case 1, other samples were also tested positive, including vitreous humor (31.1 mg/L) and gastric contents (773.5 mg/L). In case 2, metformin was measured at 844.9 mg/L in urine. Metformin hair concentrations were 28.3–44.8 and 22.5 ng/mg for both cases, respectively. The concentrations found in the 2 fatal cases are clearly higher than those obtained in a previous study with subjects under treatment (0.3–3.8 ng/mg) or those found in 3 post-mortem cases where metformin death was excluded (0.6–1.4 ng/mg). Excessive sweating during the agonal phase due to fatal hypoglycemia could explain these elevated concentrations as sweat can have contaminated the hair.