Effects of short-term continuous subcutaneous insulin infusion on fasting plasma fibroblast growth factor-21 levels in patients with newly diagnosed type 2 diabetes mellitus

Background

To investigate the effects of short-term continuous subcutaneous insulin infusion (CSII) on plasma fibroblast growth factor-21 (FGF-21) levels in patients with newly diagnosed type 2 diabetes mellitus (nT2DM).

Method

Sixty-eight patients with nT2DM (nT2DM group), and 52 gender-, age- and body mass index (BMI) -matched normal glucose tolerance (NGT group) controls participated in the study. 30 nT2DM patients with FBG≥14.0 mmol/L were treated with CSII for 2 weeks, and were underwent a euglycemic–hyperinsulinemic clamp pre- and post-treatment. Plasma FGF-21 concentrations were measured with a commercial ELISA kit. The relationship between plasma FGF-21 levels and metabolic parameters was also analyzed.

Results

Fasting plasma FGF-21 levels were higher in the nT2DM group than in NGT groups (1.60±0.08 vs. 1.13±0.26 µg/L, P<0.01). In nT2DM patients, fasting plasma FGF-21 concentrations were significantly decreased after CSII treatment for 2 weeks (1.60±0.08 vs.1.30±0.05 µg/L, P<0.05), accompanied by a significant increase in the whole body glucose uptake (M value) and blood glucose control. The changes in plasma FGF-21 levels (ΔFGF-21) were positively associated with the amelioration of insulin resistance shown by the changes in M value.

Conclusion

Plasma FGF-21 level is associated with whole body insulin sensitivity and significantly reduced following short-term CSII treatment.     

2 型糖尿病患者血浆成纤维细胞生长因子-21 水平的变化及意义

目的:探讨2型糖尿病(type 2 diabetes mellitus,T2DM)患者血浆成纤维细胞生长因子-21(fibroblast growth factor 21,FGF-21)水平变化以及观察短期胰岛素强化治疗对FGF-21水平的影响。方法:选择我院2013年1月至2015年1月收治的T2DM患者64例,其中初诊T2DM患者32例(T2DM组),T2DM合并大血管病变患者32例(合并大血管病变组),并选择同期体检健康者30例(对照组)。采用酶联免疫法测定三组血浆FGF-21水平以及胰岛素强化治疗前后的变化,分析血浆FGF-21水平与体质量指数(BMI)、腰臀比(WHR)、血脂、血糖、空腹血浆胰岛素(FINS)和糖化血红蛋白(Hb A1C)等水平的关系。结果:T2DM组及T2DM合并大血管病变组患者空腹血浆FGF-21水平明显高于对照组(P0.05),T2DM合并大血管病变组患者空腹血浆FGF-21水平明显高于T2DM组和对照组(P0.05)。空腹血浆FGF-21水平与T2DM患者FPG、Hb A1C水平呈明显正相关,WHR、舒张压、Hb A1C是影响血浆FGF-21水平的独立相关因素。经胰岛素强化治疗后,血浆FGF-21水平较治疗前明显下降(P0.05)。结论:T2DM患者血浆FGF-21水平明显升高,可能参与了T2DM及其大血管病变的发生和发展,胰岛素强化治疗可明显降低T2DM患者血浆FGF-21水平,血浆FGF-21可能作为T2DM病情和疗效评估的参考指标。     

Serum concentrations of fibroblast growth factor 19 in patients with obesity and type 2 diabetes mellitus: the influence of acute hyperinsulinemia, very-low calorie diet and PPAR-α agonist treatment

The aim of our study was to measure serum concentrations of fibroblast growth factor 19 (FGF-19) in patients with obesity (OB), obesity and type 2 diabetes mellitus (T2DM) and healthy subjects (C) at baseline and after selected interventions. We measured serum FGF-19 levels and other biochemical and hormonal parameters in 29 OB and 19 T2DM females and 30 sex- and age-matched control subjects. The interventions were acute hyperinsulinemia during isoglycemic-hyperinsulinemic clamp (n=11 for T2DM and 10 for C), very-low calorie diet (VLCD, n=12 for OB) and 3 months treatment with PPAR-alpha agonist fenofibrate (n=11 for T2DM). Baseline serum FGF-19 levels were significantly lower in OB relative to C group (132.1+/-12.7 vs. 202.2+/-16.7 pg/ml, p<0.05), while no significant difference was observed between T2DM and OB or control group. Acute hyperinsulinemia tended to decrease FGF-19 levels in both healthy and T2DM subjects. Three weeks of VLCD in OB group had no significant effect on FGF-19, whereas three months of fenofibrate treatment markedly reduced FGF-19 levels in T2DM patients (194.58+/-26.2 vs. 107.47+/-25.0 pg/ml, p<0.05). We conclude that FGF-19 levels in our study were at least partially dependent upon nutritional status, but were not related to parameters of glucose metabolism or insulin sensitivity.     

成纤维细胞生长因子21对1型糖尿病动物模型的肝糖代谢影响及机制研究

成纤维细胞生长因子(FGF)-21是FGF家族的成员之一.作为近年发现的一种新的糖代谢调节因子,大量研究表明,FGF-21是一种不依赖胰岛素,能够独立降糖的2型糖尿病治疗潜力型药物.但是,能否应用于1型糖尿病的治疗,国内外目前尚无报道.通过改良传统造模方法,诱导小鼠缓慢产生糖耐量异常,研究FGF-21对此类模型的糖代谢影响及肝糖代谢机制.通过检测FGF-21短期注射和长期注射后模型动物血糖的变化,研究FGF-21在模型动物上对血糖的调控效果.采用实时定量PCR检测FGF-21对模型动物肝脏中葡萄糖转运蛋白(GLUT)1、4 mRNA的表达影响.利用蒽酮法检测模型动物肝脏中糖原合成量.实验结果显示,FGF-21能够调节1型糖尿病动物的血糖水平,并呈剂量依赖性.同时,首次在1型糖尿病动物模型上证实了低剂量FGF-21(0.125 mg/kg)与胰岛素的协同作用效果优于相同剂量FGF-21和胰岛素单独注射的效果.治疗结果表明,FGF-21能够维持1型糖尿病动物模型血糖在正常范围,效果优于胰岛素.实时定量PCR结果发现,与胰岛素上调GLUT4 mRNA表达量不同的是,FGF-21作用动物模型8周后,GLUT1 mRNA表达量显著提高,长期的FGF-21与胰岛素协同注射使GLUT1、4 mRNA表达量同时显著提高.长期FGF-21与胰岛素协同注射组和高剂量FGF-21注射均可显著提高模型动物肝糖原的合成.结果表明,FGF-21促进动物模型糖代谢机制与增加GLUT1表达、增加糖原合成作用有关.为临床应用FGF-21治疗1型糖尿病,增加胰岛素敏感性提供了理论依据.     

Heparanase levels are elevated in the urine and plasma of type 2 diabetes patients and associate with blood glucose levels

Heparanase is an endoglycosidase that specifically cleaves heparan sulfate side chains of heparan sulfate proteoglycans. Utilizing an ELISA method capable of detection and quantification of heparanase, we examined heparanase levels in the plasma and urine of a cohort of 29 patients diagnosed with type 2 diabetes mellitus (T2DM), 14 T2DM patients who underwent kidney transplantation, and 47 healthy volunteers. We provide evidence that heparanase levels in the urine of T2DM patients are markedly elevated compared to healthy controls (1162 ± 181 vs. 156 ± 29.6 pg/ml for T2DM and healthy controls, respectively), increase that is statistically highly significant (P<0.0001). Notably, heparanase levels were appreciably decreased in the urine of T2DM patients who underwent kidney transplantation, albeit remained still higher than healthy individuals (P<0.0001). Increased heparanase levels were also found in the plasma of T2DM patients. Importantly, urine heparanase was associated with elevated blood glucose levels, implying that glucose mediates heparanase upregulation and secretion into the urine and blood. Utilizing an in vitro system, we show that insulin stimulates heparanase secretion by kidney 293 cells, and even higher secretion is observed when insulin is added to cells maintained under high glucose conditions. These results provide evidence for a significant involvement of heparanase in diabetic complications.     

达格列净对2型糖尿病合并非酒精性脂肪性肝病患者血清FGF-21水平的影响

摘要 目的：分析血清成纤维细胞生长因子-21（FGF-21）与2型糖尿病（T2DM）合并非酒精性脂肪性肝病（NAFLD）患者常见指标及NAFLD纤维化评分（NFS）的相关性,进一步探讨达格列净对T2DM合并NAFLD患者血清FGF-21水平的影响。方法：选取2022年1月至2022年6月徐州医科大学附属徐州市立医院收治的80例T2DM合并NAFLD患者为研究对象（T2DM合并NAFLD组）,选择同期80例T2DM不合并NAFLD患者为T2DM组。收集腰围（WC）、身高、体重数据,计算体重指数（BMI）。测定空腹血糖（FPG）、糖化血红蛋白（HbA1c）、空腹胰岛素（FINS）、甘油三酯（TG）、总胆固醇（TC）、高密度脂蛋白胆固醇（HDL-c）,低密度脂蛋白胆固醇（LDL-c）、肌酐（Cr）、丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST ）、白蛋白（Alb）、血小板计数（PLT）等指标,计算胰岛素抵抗指数（HOMA-IR）、NFS。采用酶联免疫吸附（ELISA）法测定FGF-21水平。比较T2DM组和T2DM合并NAFLD组各项指标的差异,探讨血清FGF-21水平与T2DM合并NAFLD患者其他指标的相关性,Logistic回归分析T2DM合并NAFLD的影响因素,受试者工作特征曲线（ROC）分析各影响因素对T2DM合并NAFLD的诊断价值。将80例T2DM合并NAFLD患者按随机数字表法随机分为二甲双胍组和达格列净组各40例,治疗前后观测各项指标变化,并密切监测不良反应。结果：T2DM合并NAFLD组患者WC、BMI、FINS、HbA1c、TG、AST、ALT、HOMA-IR、NFS及FGF-21均高于 T2DM组（P＜0.05）。相关性分析显示,FGF-21水平与T2DM合并NAFLD组患者WC、BMI、HbA1c、TG、HOMA-IR、NFS均存在正相关（P<0.05）。Logistic回归分析显示,BMI、HbA1c、FGF-21、HOMA-IR为影响T2DM患者合并NAFLD的危险因素。ROC曲线分析显示,BMI、HbA1c、FGF-21、HOMA-IR对T2DM合并NAFLD均具有一定预测价值,其中以FGF-21的预测效能最佳。治疗后,达格列净组TG、AST、ALT、NFS、FGF-21水平较二甲双胍组降低更为明显（P＜0.05）。结论：血清FGF-21水平为T2DM合并NAFLD的危险因素,参与了T2DM合并NAFLD发病及进展,且对T2DM合并NAFLD有较好的预测效能。相较于二甲双胍,达格列净可明显降低T2DM合并NAFLD患者血清FGF-21水平并改善NFS,具有一定程度的肝脏保护作用。     

Serum levels of FGF-21 are increased in coronary heart disease patients and are independently associated with adverse lipid profile

Background

Fibroblast growth factor 21 (FGF-21) is a metabolic regulator with multiple beneficial effects on glucose homeostasis and lipid metabolism in animal models. The relationship between plasma levels of FGF-21 and coronary heart disease (CHD) in unknown.

Methodology/Principal Findings

This study aimed to investigate the correlation of serum FGF-21 levels and lipid metabolism in the patients with coronary heart disease. We performed a logistic regression analysis of the relation between serum levels of FGF-21 and CHD patients with and without diabetes and hypertension. This study was conducted in the Departments of Endocrinology and Cardiovascular Diseases at two University Hospitals. Participants consisted of one hundred and thirty-five patients who have been diagnosed to have CHD and sixty-one control subjects. Serum FGF-21 level and levels of fasting blood glucose; triglyceride; apolipoprotein B100; HOMA-IR; insulin; total cholesterol; HDL-cholesterol; LDL-cholesterol; and C-reactive protein were measured. We found that median serum FGF-21 levels were significantly higher in CHD than that of control subjects (P<0.0001). Serum FGF-21 levels in CHD patients with diabetes, hypertension, or both were higher than that of patients without these comorbidities. Serum FGF-21 levels correlated positively with triglycerides, fasting blood glucose, apolipoprotein B100, insulin and HOMA-IR but negatively with HDL-C and apolipoprotein A1 after adjusting for BMI, diabetes and hypertension. Logistic regression analysis demonstrated that FGF-21 showed an independent association with triglyceride and apolipoprotein A1.

Conclusions/Significance

High levels of FGF-21 are associated with adverse lipid profiles in CHD patients. The paradoxical increase of serum FGF-21 in CHD patients may indicate a compensatory response or resistance to FGF-21.     

Expression of Fibroblast Growth Factor-21 in Muscle Is Associated with Lipodystrophy,Insulin Resistance and Lipid Disturbances in Patients with HIV

BackgroundFibroblast growth factor (FGF)-21 is a novel regulator of glucose and lipid metabolism. Recently, increased FGF-21 mRNA expression in muscle was found in patients with type 2 diabetes, but the role for FGF-21 in muscle is not well understood. Patients with HIV-infection and lipodystrophy are characterised by various degree of lipid-driven insulin resistance. We hypothesized that muscle FGF-21 mRNA would be altered in HIV patients with lipodystrophy.DesignTwenty-five HIV-infected men with lipodystrophy (LD) and 15 age-matched healthy controls, received an oral glucose tolerance test and a euglycemic-hyperinsulinemic clamp (50 mU/m2/min) combined with 6,6-H₂ glucose infusion. Muscle biopsies were obtained and FGF-21 mRNA and glycogen synthase (GS) activity were measured.ResultsSubjects with HIV were insulin resistant compared with non-HIV subjects. Compared to controls, HIV subjects demonstrated a twofold increase of plasma FGF-21 from 70.4±56.8 pg/ml vs 109.1±71.8 pg/ml, respectively (p = 0.04) and an eight-fold increase in muscular FGF-21 mRNA expression (p = 0.001). Muscle FGF-21 mRNA correlated inversely with the rate of disappearance of glucose during insulin clamp (r = −0.54, p = 0.0009), and the GS fractional velocity in muscle (r = −0.39, p = 0.03), and directly with fasting insulin (r = 0.50, p = 0.0022), HOMA-IR (r = 0.47, p = 0.004), triglycerides (r = 0.60. P = 0.0001), waist-to-hip ratio (r = 0.51, p = 0.0001) and limb fat mass (−0.46, p = 0.004), but not to plasma FGF-21.ConclusionFGF-21 mRNA is increased in skeletal muscle in HIV patients and correlates to whole-body (primarily reflecting muscle) insulin resistance, but not to plasma FGF-21. Those findings add to the evidence that FGF-21 is a myokine and may suggest that muscle FGF-21 is working in a local manner.     

Elevated circulating vaspin levels were decreased by rosiglitazone therapy in T2DM patients with poor glycemic control on metformin alone

Vaspin has been regarded as a novel adipokine with potential insulin sensitizing properties. The aim of the present study is to investigate the effects of rosiglitazone therapy on plasma vaspin in type 2 diabetes patients (T2DM) inadequately controlled on metformin alone. A total of 105 subjects, including 37 subjects with normal glucose tolerance (NGT), 37 subjects with impaired glucose regulating (IGR), and 31 T2DM patients with poor glycemic control on metformin alone were enrolled in this study. Fasting plasma vaspin levels were higher in T2DM patients with poor glycemic control than that in IGR and NGT groups (1.19 ± 0.74 vs. 0.46 ± 0.26 and 0.54 ± 0.28 μg/L, P < 0.05). There was no difference between IGR and NGT groups. In T2DM patients, fasting plasma vaspin concentrations were significantly decreased after rosiglizatone therapy for 12 weeks (1.19 ± 0.74 vs. 0.91 ± 0.54 μg/L, P < 0.05), accompanied with significant amelioration of insulin sensitivity and glucose control. Plasma vaspin levels were positively associated with the fasting insulin and the homeostasis model assessment of IR (HOMA-IR). In conclusion, plasma vaspin level is higher in T2DM patients with poor glycemic control. And rosiglitazone therapy decreased plasma vaspin levels through glucose and insulin sensitivity regulation.     

米格列奈与瑞格列奈分别联合二甲双胍在新诊断2型糖尿病的临床价值比较

目的：探讨米格列奈和瑞格列奈在治疗新诊断2型糖尿病的临床价值比较。方法：将2010年1月至2012年12月间我院新诊断的120例2型糖尿病患者随机分为A、B两组,其中A组患者60例,采用瑞格列奈联合二甲双胍进行治疗,B组患者60例,采用米格列奈联合二甲双胍进行治疗。对两组患者血糖水平及12周后相应指标进行统计分析。结果：治疗3天后两组患者的空腹血糖及餐后血糖水平明显低于治疗前,B组患者血糖降低幅度大于A组（P〈0．05）;治疗12周后,两组空腹血糖及餐后血糖水平显著减小,B组减小程度高于A组;患者空腹及餐后胰岛素水平有一定的增加,B组增加程度高于A组;B组患者HbAlc的降低程度高于A组;两组同时还可以降低HOMA胰岛素的抵抗指数以及增大胰岛素的敏感指数,其中B组效果好于A组;B组患者出现低血糖的人次少于A组。结论：米格列奈与瑞格列奈分别联合二甲双胍可以短期降低新诊断2型糖尿病患者的血糖水平,在中期治疗后米格列奈联合二甲双胍可以更有效的改善患者糖尿病的各项指标。     

FGF-23/Vitamin D Axis in Type 1 Diabetes: The Potential Role of Mineral Metabolism in Arterial Stiffness

ObjectiveTo investigate the usefulness of Fibroblast Growth Factor 23 (FGF-23) and vitamin D as possible biomarkers of pre-clinical atherosclerosis, assessed as arterial stiffness (AS), in a group of subjects with type 1 diabetes (T1DM) and no previous cardiovascular events.ResultsPatients with T1DM had higher aPWV compared with controls (p<0.001), but they did not present differences in 25(OH)D (70.3(50.4–86.2)nmol/L vs. 70.7(59.7–83.0)nmol/L; p = 0.462) and in FGF-23 plasma concentrations (70.1(38.4–151.9)RU/mL vs. 77.6(51.8–113.9)RU/mL; p = 0.329). In T1DM patients, higher concentrations of FGF-23 were positively associated with aPWV after adjusting for eGFR and classical cardiovascular risk factors (model 1: ß = 0.202, p = 0.026), other mineral metabolism parameters (model 2: ß = 0.214, p = 0.015), microvascular complications, low-grade inflammation and ED markers (model 3: ß = 0.170, p = 0.045). Lower 25(OH)D concentrations were also associated with higher aPWV after adjusting for all the above-mentioned factors (model 3: ß = -0.241, p = 0.015).ConclusionsWe conclude that both FGF-23 plasma concentrations (positively) and 25(OH)D serum concentrations (negatively) are associated with AS in patients with T1DM and no previous cardiovascular events.     

成纤维细胞生长因子(FGF)-21改善胰岛素抵抗肝细胞对葡萄糖的吸收和肝糖原的合成

在体外建立胰岛素抵抗肝细胞模型,探讨在胰岛素抵抗状态下成纤维细胞生长因子(FGF)-21对模型细胞糖代谢的影响及机制．将HepG2细胞置于10^-7 mol/L 的胰岛素培养基中培养24 h,建立胰岛素抵抗细胞模型．分别用不同浓度的胰岛素和FGF-21处理模型细胞,采用葡萄糖氧化酶-过氧化物酶(GOD-POD)法检测细胞对葡萄糖的摄取情况,并检查胰岛素与FGF-21的协同作用．利用实时荧光定量PCR检测FGF-21对模型细胞葡萄糖转运蛋白1(GLUT1)mRNA表达的影响,蒽酮法检测模型细胞糖原合成量,探讨FGF-21对胰岛素抵抗细胞模型葡萄糖摄取的影响及机制．结果发现,用高浓度胰岛素处理HepG2细胞24 h后,细胞对胰岛素的敏感性显著降低,说明成功建立了胰岛素抵抗细胞模型,抵抗状态可维持48 h,未发现细胞形态学变化．FGF-21能改善胰岛素抵抗模型细胞的葡萄糖摄取,参与肝糖原的合成,并与胰岛素产生协同作用．实时荧光定量PCR结果发现,FGF-21作用模型细胞后,细胞的GLUT1 mRNA表达量显著增加,说明FGF-21促进模型细胞摄取葡萄糖的作用机制与其增加GLUT1的表达有关．     

Can primary hyperaldosteronism be considered as a specific form of diabetes mellitus?

Aldosterone-producing adenoma (aldosteronoma)--the most frequent form of primary hyperaldosteronism (PH)--is considered a specific form of diabetes mellitus (DM). In a previous study we demonstrated insulin resistance in patients with PH. We have therefore undertaken a study to evaluate the incidence of abnormalities of glucose metabolism in patients with PH (36 subjects) compared to control subjects with essential hypertension (EH) (21 patients). The following parameters were measured in all studied subjects: office blood pressure (by mercury sphygmomanometer in the sitting position), body mass index (BMI), plasma potassium, plasma glucose and insulin levels during oral glucose tolerance test (OGTT) (0, 60, 120 min), plasma renin activity and plasma aldosterone. Although patients with PH tended to have higher stimulated plasma glucose levels after 60 and 120 min compared to EH, these differences did not attain statistical significance. Patients with EH tended to have higher insulin levels at each measured interval, but due to a high variability these differences were again not significant. There were no significant differences between PH and EH in the proportion of diabetics (20% vs. 14%) or patients with impaired glucose tolerance (18% vs. 10%). In conclusion, we have found the absence of significant differences in the frequency of diabetes mellitus, impaired glucose tolerance and insulin resistance in patients with EH and PH. Our data thus do not support the idea of primary hyperaldosteronism as a specific type of diabetes mellitus. Furthermore, our results indicate that glucose metabolic characteristics in essential hypertension and primary hyperaldosteronism tend to be similar. The definitive conclusion with respect to the possible causal relationship between DM and PH, however, can be obtained only on larger groups of subjects, in particular after the evaluation of the effect of surgical/pharmacological treatment of primary hyperaldosteronism.     

Molecular determinants of FGF-21 activity-synergy and cross-talk with PPARgamma signaling

Fibroblast growth factor (FGF)-21 is a novel regulator of insulin-independent glucose transport in 3T3-L1 adipocytes and has glucose and triglyceride lowering effects in rodent models of diabetes. The precise mechanisms whereby FGF-21 regulates metabolism remain to be determined. Here we describe the early signaling events triggered by FGF-21 treatment of 3T3-L1 adipocytes and reveal a functional interplay between FGF-21 and peroxisome proliferator-activated receptor gamma (PPARgamma) pathways that leads to a marked stimulation of glucose transport. While the early actions of FGF-21 on 3T3-L1 adipocytes involve rapid accumulation of intracellular calcium and phosphorylation of Akt, GSK-3, p70(S6K), SHP-2, MEK1/2, and Stat3, continuous treatment for 72 h induces an increase in PPARgamma protein expression. Moreover, chronic activation of the PPARgamma pathway in 3T3-L1 adipocytes with the PPARgamma agonist and anti-diabetic agent, rosiglitazone (BRL 49653), enhances FGF-21 action to induce tyrosine phosphorylation of FGF receptor-2. Strikingly, treatment of cells with FGF-21 and rosiglitazone in combination leads to a pronounced increase in expression of the GLUT1 glucose transporter and a marked synergy in stimulation of glucose transport. Together these results reveal a novel synergy between two regulators of glucose homeostasis, FGF-21 and PPARgamma, and further define FGF-21 mechanism of action.     

Kinetic Modeling of Human Hepatic Glucose Metabolism in Type 2 Diabetes Mellitus Predicts Higher Risk of Hypoglycemic Events in Rigorous Insulin Therapy

A major problem in the insulin therapy of patients with diabetes type 2 (T2DM) is the increased occurrence of hypoglycemic events which, if left untreated, may cause confusion or fainting and in severe cases seizures, coma, and even death. To elucidate the potential contribution of the liver to hypoglycemia in T2DM we applied a detailed kinetic model of human hepatic glucose metabolism to simulate changes in glycolysis, gluconeogenesis, and glycogen metabolism induced by deviations of the hormones insulin, glucagon, and epinephrine from their normal plasma profiles. Our simulations reveal in line with experimental and clinical data from a multitude of studies in T2DM, (i) significant changes in the relative contribution of glycolysis, gluconeogenesis, and glycogen metabolism to hepatic glucose production and hepatic glucose utilization; (ii) decreased postprandial glycogen storage as well as increased glycogen depletion in overnight fasting and short term fasting; and (iii) a shift of the set point defining the switch between hepatic glucose production and hepatic glucose utilization to elevated plasma glucose levels, respectively, in T2DM relative to normal, healthy subjects. Intriguingly, our model simulations predict a restricted gluconeogenic response of the liver under impaired hormonal signals observed in T2DM, resulting in an increased risk of hypoglycemia. The inability of hepatic glucose metabolism to effectively counterbalance a decline of the blood glucose level becomes even more pronounced in case of tightly controlled insulin treatment. Given this Janus face mode of action of insulin, our model simulations underline the great potential that normalization of the plasma glucagon profile may have for the treatment of T2DM.     

Liraglutide Increases FGF-21 Activity and Insulin Sensitivity in High Fat Diet and Adiponectin Knockdown Induced Insulin Resistance

Background

Liraglutide is a glucagon-like peptide-1 analogue that stimulates insulin secretion and improves β-cell function. However, it is not clear whether liraglutide achieves its glucose lowering effect only by its known effects or whether other as yet unknown mechanisms are involved. The aim of this study was to examine the effects of liraglutide on Fibroblast growth factor-21 (FGF-21) activity in High-fat diet (HFD) fed ApoE^−/− mice with adiponectin (Acrp30) knockdown.

Method

HFD-fed ApoE^−/− mice were treated with adenovirus vectors expressing shAcrp30 to produce insulin resistance. Hyperinsulinemic-euglycemic clamp studies were performed to evaluate insulin sensitivity of the mouse model. QRT-PCR and Western blot were used to measure the mRNA and protein expression of the target genes.

Results

The combination of HFD, ApoE deficiency, and hypoadiponectinemia resulted in an additive effect on insulin resistance. FGF-21 mRNA expressions in both liver and adipose tissues were significantly increased while FGF-21 receptor 1 (FGFR-1) and β-Klotho mRNA levels in adipose tissue, as well as FGFR-1-3 and β-Klotho mRNA levels in liver were significantly decreased in this model. Liraglutide treatment markedly improved insulin resistance and increased FGF-21 expression in liver and FGFR-3 in adipose tissue, restored β-Klotho mRNA expression in adipose tissue as well as FGFR-1-3, β-Klotho levels and phosphorylation of FGFR1 up to the levels observed in control mice in liver. Liraglutide treatment also further increased FGF-21 proteins in liver and plasma. In addition, as shown by hyperinsulinemic-euglycemic clamp, liraglutide treatment also markedly improved glucose metabolism and insulin sensitivity in these animals.

Conclusion

These findings demonstrate an additive effect of HFD, ApoE deficiency, and adiponectin knockdown on insulin resistance and unveil that the regulation of glucose metabolism and insulin sensitivity by liraglutide may be partly mediated via increased FGF-21 and its receptors action.     

Fibroblast Growth Factor 21 (FGF-21) in Peritoneal Dialysis Patients: Natural History and Metabolic Implications

Background

Human fibroblast growth factor 21 (FGF-21) is an endocrine liver hormone that stimulates adipocyte glucose uptake independently of insulin, suppresses hepatic glucose production and is involved in the regulation of body fat. Peritoneal dialysis (PD) patients suffer potential interference with FGF-21 status with as yet unknown repercussions.

Objectives

The aim of this study was to define the natural history of FGF-21 in PD patients, to analyze its relationship with glucose homeostasis parameters and to study the influence of residual renal function and peritoneal functional parameters on FGF-21 levels and their variation over time.

Methods

We studied 48 patients with uremia undergoing PD. Plasma samples were routinely obtained from each patient at baseline and at 1, 2 and 3 years after starting PD therapy.

Results

Plasma FGF-21 levels substantially increased over the first year and were maintained at high levels during the remainder of the study period (253 pg/ml (59; 685) at baseline; 582 pg/ml (60.5–949) at first year and 647 pg/ml (120.5–1116.6) at third year) (p<0.01). We found a positive correlation between time on dialysis and FGF-21 levels (p<0.001), and also, those patients with residual renal function (RRF) had significantly lower levels of FGF-21 than those without RRF (ρ -0.484, p<0.05). Lastly, there was also a significant association between FGF-21 levels and peritoneal protein losses (PPL), independent of the time on dialysis (ρ 0.410, p<0.05).

Conclusion

Our study shows that FGF-21 plasma levels in incident PD patients significantly increase during the first 3 years. This increment is dependent on or is associated with RRF and PPL (higher levels in patients with lower RRF and higher PPL). FGF-21 might be an important endocrine agent in PD patients and could act as hormonal signaling to maintain glucose homeostasis and prevent potential insulin resistance. These preliminary results suggest that FGF-21 might play a protective role as against the development of insulin resistance over time in patients undergoing a continuous glucose load.     

提高成纤维细胞生长因子-21产率和纯度

成纤维细胞生长因子-21(FGF-21)作为近期发现的新型代谢调节因子,因其具有独立于胰岛素调节糖脂代谢、增加胰岛素敏感性等作用,有望成为治疗糖尿病的新型药物。包涵体形式表达外源蛋白表达量及纯度高,但是以pET载体表达时,FGF-21以包涵体形式表达,且复性率及产率低,蛋白活性降低[1]。针对这一瓶颈问题,用SUMO载体首次以包涵体形式表达带有SUMO标签的hFGF-21,通过优化培养条件,并应用中空纤维柱膜过滤技术对菌体进行富集,对包涵体进行洗涤、变性及复性,经过亲和层析、凝胶过滤层析的纯化方法,得到了成熟的hFGF-21,在保证蛋白活性的同时增加了蛋白的产量及纯度。通过检测HepG2细胞葡萄糖吸收及2型糖尿病db/db小鼠短期及长期血糖变化鉴定其降糖生物学活性。结果表明,以包涵体形式表达hFGF-21(ihFGF-21)的表达量是可溶形式表达的hFGF-21(shFGF-21)的3倍,最终ihFGF-21的收率为20 mg/L,而shFGF-21的收率仅为6 mg/L。ihFGF-21的纯度可达到95%以上,而shFGF-21仅能达到90%左右;在细胞水平和动物水平上两者的降糖生物学活性一致。在保证hFGF-21生物学活性的前提下,与传统包涵体途径提取目的蛋白的方法相比,应用中空纤维柱膜过滤技术使hFGF-21的生产周期缩短了约1/3左右。综上所述,此法为FGF-21中试及工业化生产提供了高效、经济的策略。     

Patterns of Circulating Fibroblast Growth Factor 21 in Subjects with and without Type 2 Diabetes

Background

Fibroblast growth factor 21 (FGF21) exerts wide-range effects on carbohydrate and lipid metabolism. However, its perturbation in type 2 diabetes mellitus (T2DM) remains elusive. Besides, previous human studies in T2DM simply investigated fasting or stimulated levels of FGF21. The current study sought to evaluate the temporal changes of circulating FGF21 in subjects with and without T2DM.

Methods

Ten patients with T2DM and 16 normal controls (NC) were recruited. Participants were categorized as obese (BMI≥25 kg/m²) or lean (BMI<25 kg/m²). Blood samples were drawn every 30 min within 7 hours (8 a.m.-3 p.m.). Serum FGF21, blood glucose, insulin, free fatty acids (FFAs) and adiponectin were measured in all subjects.

Results

The peak levels of FGF21 were observed in the fasting state (8 a.m.) both in T2DM and NC groups (267.35 ±158.72 ng/L vs. 178.93±121.37 ng/L, P = 0.096). FGF21 AUC did not differ significantly between the two groups (T2DM: 949.4±471.47 ng/L; NC: 883.13±561.40 ng/L, P = 0.770). Obese subjects had higher FGF21 levels than lean ones in patients either with or without T2DM. The pattern of FFAs closely resembled that of FGF21. Correlation analysis showed that temporal levels of FGF21 were significantly related to FFAs (r = 0.749, P = 0.002),but not blood glucose, insulin or adiponectin (all P> 0.05).

Conclusions

These findings suggest that the pattern of circulating FGF21 does not differ significantly between T2DM and NC,although T2DM patients showed a trend toward higher fasting FGF21 than healthy subjects. The pattern of circulating FFAs is significantly associated with that of FGF21.     

双歧杆菌四联活菌片辅助治疗对新诊断2型糖尿病患者血清炎症因子及氧化应激指标水平的调节作用

目的 探讨双歧杆菌四联活菌片辅助治疗对新诊断2型糖尿病(T2DM)患者血清炎症因子及氧化应激指标水平的调节作用。 方法 选取我院2017年4月至2019年5月收治的108例新诊断T2DM患者为研究对象,患者随机分为观察组和对照组各54例。两组患者均予以健康教育、饮食控制和运动锻炼等基础治疗。对照组患者在基础治疗的同时给予甘精胰岛素与阿卡波糖控制血糖;观察组患者在对照组基础上加用双歧杆菌四联活菌片治疗,1.5 g/次,3次/d,温开水服用。两组患者均连用12周。观察两组患者治疗前和治疗12周后血糖控制情况、β细胞功能、血清炎症指标[超敏C反应蛋白(hsCRP)、白介素(IL)6和肿瘤坏死因子(TNF)α]水平及氧化应激指标[谷胱甘肽过氧化物酶(GSHPX)和晚期氧化蛋白产物(AOPP)]水平的变化。 结果 治疗12周后,两组患者血清FBG[(6.52±0.74)mmol/L、(5.78±0.62)mmol/L]和HbA1C水平[(7.42±0.93)%、(6.74±0.87)%]较治疗前明显下降,HOMAβ水平(44.78±4.79、51.87±5.27)较治疗前明显上升(均P结论 双歧杆菌四联活菌片辅助治疗新诊断T2DM患者可改善其糖代谢指标水平和胰岛素抵抗,有利于血糖达标,其作用机制可能与其能控制炎症反应和减轻氧化应激反应相关。