EGCG防治糖尿病作用及机制研究进展

表没食子儿茶素没食子酸酯(Epigallocatechin gallate,EGCG)是绿茶中的主要活性成分,具有抗癌、抑制肥胖、缓解代谢综合征等功效。本文总结EGCG预防和缓解糖尿病的相关研究,从降血糖功效、胰岛素抵抗、胰岛素分泌、糖尿病常见并发症等方面综合分析和阐述EGCG的作用机制,以期为绿茶缓解代谢综合征研究提供理论支持。     

SUMO-cFGF-21发酵工艺优化及其降糖效果研究

研究旨在优化SUMO-cFGF-21发酵工艺,同时检测cFGF-21蛋白对糖尿病小鼠和犬血糖的降糖效果。通过SDS-PAGE电泳分析发酵条件(菌种、工程菌OD600、诱导时间、诱导温度、诱导剂IPTG浓度)对SUMOcFGF-21蛋白表达的影响。结果表明,22号菌种蛋白表达量最高,达到上清蛋白30.5%,可作为一级菌种。发酵过程中,当工程菌OD600值约为2、诱导时间6 h、诱导温度23℃、诱导剂IPTG终浓度1 mmol·L~(-1)时,上清中SUMOcFGF-21蛋白表达量最高,达到上清蛋白19.7%。经Ni柱亲和层析,酶切去掉SUMO标签后成功制备cFGF-21蛋白。将不同剂量cFGF-21持续注射糖尿病小鼠两周,以有效剂量cFGF-21持续注射糖尿病犬两周,观察降糖效果。结果表明,与模型对照组相比,有效剂量cFGF-21均可极显著降低糖尿病小鼠和犬的血糖(P0.01)。研究成功优化SUMO-cFGF-21蛋白中试发酵工艺,并检测cFGF-21蛋白对糖尿病小鼠和犬血糖的降糖效果,为临床应用cFGF-21治疗犬糖尿病提供依据。     

Ⅱ型糖尿病骨质疏松与血管钙化的相关性分析

目的分析Ⅱ型糖尿病患者骨质疏松和骨量减少与血管钙化之间的关联性,为早期诊断和预防糖尿病性骨质疏松提供依据．方法按入选标准对59例Ⅱ型糖尿病患者记录临床体征、血液实验室检查结果．采用双能x线吸收法测定腰椎和股骨颈骨密度值,x线摄片记录胸主动脉和髂动脉的血管钙化情况,并对各因素与糖尿病性骨质疏松相关性进行分析．结果腰椎骨量分析可见：骨质疏松6例（10．2％）,骨量减少27例（45．8％）;股骨颈骨量分析可见：骨质疏松7例（11．8％）,骨量减少28例（49％）．髂动脉钙化与腰椎（L1—L4）骨质疏松（P=0．04）和股骨颈骨质疏松（P=0．036）存在显著相关性．结论Ⅱ型糖尿病患者髂动脉钙化与骨质疏松呈正相关,发现动脉钙化可能提示骨质疏松或骨量减少的存在．     

蝮蛇抗栓酶治疗糖尿病性神经病变的疗效观察

本文以蝮蛇抗栓酶(654-2、B族维生素作对照)对糖尿病性神经病变患者作了疗效观察。结果表明,二种药物有效率各为:蝮蛇抗栓酶组97.5％,654-2组87.5％,维生素B族28％(前两组比较P>0.05,1、3组比较P<0.005)。3组药物副作用比较以654-2组反应最高、最重,不易为患者所耐受,而蝮蛇抗栓酶未见任何副作用,且对改善患者症状、体征和神经传导功能有明显效果,并有降血脂、血糖作用。     

Endogenous serum insulin concentration in dogs with diabetic ketoacidosis

Objective: To determine endogenous serum insulin concentration in dogs with diabetic ketoacidosis (DKA), and to compare it to endogenous serum insulin concentration in diabetic dogs with ketonuria but no acidosis (KDM), diabetic dogs with uncomplicated diabetes mellitus (DM) that did not have ketonuria or acidosis, and dogs with non‐pancreatic disease (NP). Design: Prospective study. Setting: Veterinary Hospital of the University of Pennsylvania. Animals: Forty‐four client‐owned dogs; 20 dogs with newly diagnosed diabetes mellitus (7 dogs with DKA, 6 dogs with KDM, and 7 dogs with DM) and 24 dogs with non‐pancreatic disease. Interventions: Blood and urine samples were obtained at the time of admission to the hospital. Measurements and main results: Signalment, clinical signs, physical examination findings, and concurrent disease were recorded for all dogs. Blood glucose concentration, venous blood pH, venous blood HCO3^? concentration, urinalysis, and endogenous serum insulin concentration were determined in all dogs. Dogs with DKA have significantly decreased endogenous serum insulin concentrations compared to dogs with DM (P = 0.03) and dogs with non‐pancreatic disease (P = 0.0002), but not compared to dogs with KDM (P = 0.2). Five of 7 dogs with DKA had detectable endogenous serum insulin concentrations, and 2 of these dogs had endogenous serum insulin concentration within the normal range. Conclusions: Diabetic dogs with ketoacidosis have significantly decreased endogenous serum insulin concentration compared to dogs with uncomplicated diabetes mellitus. However, most dogs with DKA have detectable endogenous serum insulin concentrations, and some dogs with DKA have endogenous serum insulin concentrations within the normal range.     

Clinical Value of Fructosamine Measurements in Non-healthy Dogs

Ninety-three unhealthy dogs (including some with diabetes mellitus or insulinoma) of different ages, sex and breeds were divided into 10 groups according to their pathology. Serum fructosamine concentrations were determined using a commercial colorimetric nitroblue tetrazolium method. Diabetic dogs had the highest fructosamine concentrations (454.85±149.34 mol/L). Dogs with insulinoma had significantly lower fructosamine concentrations (202.80±31.22 mol/L), similar to those with leishmaniosis (202.83±99.83 mol/L). Fructosamine concentrations in non-healthy dogs, except those with diabetes mellitus, insulinoma or leishmaniosis, were within the reference limits previously reported.     

Evaluation of the oral antihyperglycemic drug metformin in normal and diabetic cats

Metformin is an oral antidiabetic drug that improves control of glycemia primarily by inhibiting hepatic gluconeogenesis and glycogenolysis. This study evaluated the usefulness of metformin for the treatment of diabetes mellitus in cats. The study consisted of 3 phases. Phase I was a dose-finding study performed in healthy cats that were randomly administered varying doses of metformin to determine the approximate dose that would yield plasma concentrations known to be effective in humans. Phase 2 was a 3-week safety study performed in healthy cats to determine if cats could tolerate the daily oral dose and administration protocol identified during phase 1. Phase 3 was a clinical trial evaluating the clinical response of diabetic cats to oral metformin treatment. Five cats with newly diagnosed, naturally acquired diabetes mellitus were enrolled in phase 3. Plasma metformin concentrations in the therapeutic range of 0.5-2 microg/mL were achieved with doses of 50 mg/cat PO q12h without dramatic drug accumulation. Intermittent lethargy, inappetence, vomiting, and weight loss were identified, and the results of the CBC, serum biochemical analysis, plasma lactate concentration, and urinalysis remained within the reference range during phase 2 of the study. During phase 3, control of glycemia was achieved in 1 of 5 diabetic cats after 8 weeks of metformin treatment; 3 cats failed to respond to metformin, and treatment with insulin was initiated after 7-8 weeks of metformin treatment; 1 cat died unexpectedly 11 days after starting metformin treatment. The cause of death was not determined. The serum insulin concentration was within or greater than the reference range in the responder diabetic cat and was undetectable or at the low end of the reference range in the nonresponder diabetic cats. The results of this study suggest that metformin is beneficial only in those diabetic cats with detectable concentrations of insulin at the time metformin treatment is initiated.     

Evaluation of an insulin zinc suspension for control of naturally occurring diabetes mellitus in dogs

OBJECTIVE: To evaluate duration of action of an insulin zinc suspension (Caninsulin, Intervet) in spontaneously occurring cases of canine diabetes mellitus and suitability of its use as a once daily administered insulin for treatment of this disease. DESIGN: Eight client-owned canine diabetics were included in a prospective pilot study. All dogs had been treated with Caninsulin for a minimum of 2 months and were considered on clinical grounds to be adequately stabilised. PROCEDURE: Dogs were hospitalised for 24 h and blood collected every 2 h via indwelling venous catheters for blood glucose determination. RESULTS: Once daily Caninsulin administration failed to maintain glycaemic control for greater than 13 h in five of eight dogs, but acceptable blood glucose concentrations were maintained for 22 h and greater than 24 h in two others. One dog became distressed during hospitalisation and the blood glucose curve did not show an identifiable response to the insulin. CONCLUSION: Most diabetic dogs may require twice daily administration of Caninsulin for satisfactory glycaemic control, but once daily administration may be adequate in some animals. More comprehensive investigation into duration of activity of Caninsulin is warranted.     

The effect of cordycepin on brain oxidative stress and protein expression in streptozotocin-induced diabetic mice

Diabetes mellitus (DM) is characterized by metabolic disorders and psychological deficits, including cognitive decline. Here, we investigated the effect of cordycepin on oxidative stress and protein expression in the brains of diabetic mice. Twenty-four mice were divided into four groups, one comprising untreated healthy mice (N); one comprising healthy mice treated with cordycepin (24 mg/kg body weight) (N+Cor); one comprising untreated DM mice; and one comprising DM mice treated with cordycepin (24 mg/kg body weight) (DM+Cor). After 14 days of treatment, cognitive behavior was assessed using the novel object recognition (NOR) test. The brain levels of oxidative stress markers (glutathione, catalase, and superoxide dismutase) were examined using the respective detection kits. Protein expression in brain tissues was assessed by liquid chromatography with tandem mass spectrometry (LC–MS/MS); the functions of the identified proteins were annotated by PANTHER, while major protein–protein interactions were assessed using STITCH. We found that cordycepin treatment significantly decreased body weight and food and water intake in the DM+Cor group compared with that in the DM group; however, no differences in blood glucose levels were found between the two groups. Cordycepin treatment significantly reversed cognitive decline in diabetic mice in the NOR test and ameliorated antioxidant defenses. Additionally, we identified ULK1 isoform 2, a protein associated with cognitive function via the activated AMPK and autophagic pathways, as being uniquely expressed in the DM+Cor group. Our findings provide novel insights into the cellular mechanisms underlying how cordycepin improves cognitive decline in diabetic mice.     

Ⅱ型糖尿病老年人抑郁与HbA1c水平关系的研究

目的了解Ⅱ型糖尿病老年人抑郁现状及HbA1c水平,探讨Ⅱ型糖尿病老年人抑郁与HbA1c水平的关系.方法采用便利抽样法对Ⅱ型糖尿病老年人共316名进行抑郁问卷调查,并对其进行相关生化检查.结果 47.5%的Ⅱ型糖尿病老年人糖化血红蛋白（HbA1c）呈高值,且抑郁检出率为25.6%;抑郁组与非抑郁组Ⅱ型糖尿病老人FPG,2h-PG及HbA1c等生化指标存在差异（P〈0.01）;多因素Logistic回归分析结果表明：民族、并发症、抑郁是影响HbA1c水平的重要因素.结论Ⅱ型糖尿病老年人抑郁症状普遍存在,抑郁患者血糖控制能力较差,临床医生应注重糖尿病老年人的心理治疗,帮助患者及早摆脱不良心理,恢复自信,降低HbA1c水平,有效控制血糖.