Background: Type II diabetes mellitus is associated with multiple metabolic derangements which can cause secondary pathophysiological changes in multiple organ systems. This in turn can impose a heavy burden of morbid...Background: Type II diabetes mellitus is associated with multiple metabolic derangements which can cause secondary pathophysiological changes in multiple organ systems. This in turn can impose a heavy burden of morbidity and mortality from micro‑ and macro‑vascular complications. This study aimed to describe the metabolic and therapeutic profile of a subgroup of type 2 diabetic patients who have treatment failure with oral anti-hyperglycemic agents with persistent hyperglycemia despite insulin treatment. Methods: 60 type 2 diabetic patients in treatment failure with oral antidiabetics and under insulin treatment, aged 35 to 70 years, were recruited at the Diabetes Clinic of the University Teaching Hospital of Treichville in Abidjan, Côte d’Ivoire. Blood samples were collected in tubes containing Ethylenediaminetetraacetic Acid (EDTA) to determine glycated hemoglobin (HbA1c). Results: The average age of the population was 54 ± 9.38 years with a sex ratio (M/F) of 0.3, an average BMI of 30.25 ± 5 kg/m<sup>2</sup>, and an average HbA1c of 10.1% ± 1.6% for an average diabetes duration of 11.8 ± 5.8 years. The average insulin dose was 74.556 ± 16.21 UI/day, and the average duration of insulin treatment was 5.4 ± 3.1 years. The average HbA1c value was 10.1% ± 1.87% in men against 10.03% ± 1.53% in women with no significant difference (p = 0.1). The mean HbA1c values according to patient weight were 10.08% ± 2.05% for normal weight, 9.55% ± 2.26% for overweight, and 10.57% for obese, with no significant difference between the three groups of patients (p = 0.1). Conclusion: This study showed a persistence increase in glycated hemoglobin regardless of the treatment regimen, duration, and dose of insulin treatment in the subpopulation of type 2 diabetic patients.展开更多
Female Wister rats aged 8 weeks were randomly divided into sham operation group, ovariectomized (OVX) control group, and 20VX groups fed with soy isoflavone crude extract supplementation. The rats had free access to...Female Wister rats aged 8 weeks were randomly divided into sham operation group, ovariectomized (OVX) control group, and 20VX groups fed with soy isoflavone crude extract supplementation. The rats had free access to high fat diet and water for 9 weeks. No significant difference was found in body weight (BW), total abdominal fat, food intake and food utilization rate between OVX control group and 20VX groups. However, the fasting blood glucose and blood lipid levels were significantly higher in 20VX groups than in OVX control group (P〈0.05). Intraperitoneal glucose tolerance test (IGTI") showed that the area under AUC was smaller in 20VX groups than in OVX control group (P〈0.05). These findings showed that soy isoflavone crude extract supplementation can improve glucose tolerance and prevent high fat diet-induced insulin resistance in ovariectomized rats.展开更多
AIM:To investigate the effects of mitofusin-2(MFN2) on insulin sensitivity and its potential targets in the liver of rats fed with a high-fat diet(HFD).METHODS:Rats were fed with a control or HFD for 4 or 8 wk,and wer...AIM:To investigate the effects of mitofusin-2(MFN2) on insulin sensitivity and its potential targets in the liver of rats fed with a high-fat diet(HFD).METHODS:Rats were fed with a control or HFD for 4 or 8 wk,and were then infected with a control or an MFN2 expressing adenovirus once a week for 3wk starting from the 9th wk.Blood glucose(BG),plasma insulin and insulin sensitivity of rats were determined at end of the 4th and 8th wk,and after treatment with different amounts of MFN2 expressing adenovirus(108,109 or 1010 vp/kg body weight).BG levels were measured by Accu-chek Active Meter.Plasma insulin levels were analyzed by using a Rat insulin enzymelinked immunosorbent assay kit.Insulin resistance was evaluated by measuring the glucose infusion rate(GIR) using a hyperinsulinemic euglycemic clamp technique.The expression or phosphorylation levels of MFN2 and essential molecules in the insulin signaling pathway,such as insulin receptor(INSR),insulin receptor substrate 2(IRS2),phosphoinositide-3-kinase(PI3K),protein kinase beta(AKT2) and glucose transporter type 2(GLUT2) was assayed by quantitative real-time polymerase chain reaction and Western-blotting.RESULTS:After the end of 8wk,the body weight of rats receiving the normal control diet(ND) and the HFD was not significantly different(P>0.05).Compared with the ND group,GIR in the HFD group was significantly decreased(P<0.01),while the levels of BG,triglycerides(TG),total cholesterol(TC) and insulin in the HFD group were significantly higher than those in the ND group(P<0.05).Expression of MFN2 mRNA and protein in liver of rats was significantly downregulated in the HFD group(P<0.01) after 8 wk of HFD feeding.The expression of INSR,IRS2 and GLUT2 were down-regulated markedly(P<0.01).Although there were no changes in PI3K-P85 and AKT2 expression,their phosphorylation levels were decreased significantly(P<0.01).After intervention with MFN2 expressing adenovirus for 3wk,the expression of MFN2 mRNA and protein levels were up-regulated(P<0.01).There was no difference in body weight of rats between the groups.The levels of BG,TG,TC and insulin in rats were lower than those in the Ad group(P<0.05),but GIR in rats infected with Ad-MFN2 was significantly increased(P<0.01),compared with the Ad group.The expression of INSR,IRS2 and GLUT2 was increased,while phosphorylation levels of PI3K-P85 and AKT2 were increased(P<0.01),compared with the Ad group.CONCLUSION:HFDs induce insulin resistance,and this can be reversed by MFN2 over-expression targeting the insulin signaling pathway.展开更多
Background: Animal models of diet-induced obesity(DIO) are commonly used in medical research for mimicking human diseases. There is no universal animal model, and careful evaluation of variety of factors needs to be c...Background: Animal models of diet-induced obesity(DIO) are commonly used in medical research for mimicking human diseases. There is no universal animal model, and careful evaluation of variety of factors needs to be considered when designing new experiments. Here, we investigated the effect of 9 weeks high-fat diet(HFD) intervention, providing 60% energy from fat, on parameters of inflammation and insulin resistance in male C57 BL/6 J mice.Methods: Six weeks old mice were initiated on regular diet(RD) or HFD providing 60 kcal energy from fat for 9 weeks. Fasting blood glucose levels were measured by glucometer, and fasting plasma levels of insulin and proinflammatory cytokines by Luminex assay. Insulin sensitivity was evaluated by using QUICKI and HOMA2 indexes.Results: HFD mice showed ~ 40% higher body weight and ~ 20% larger abdominal circumference, due to an increase in the white adipose tissue mass. Liver examination revealed increased size and higher hepatic lipid accumulation in livers from HFD mice compared to their RD counterparts. Animals from the HFD group were characterized with significantly higher presence of crown-like structures(CLS) in WAT and higher plasma levels of proinflammatory cytokines(TNF-α, IL-6, leptin, MCP-1, PAI-1, and resistin). HFD-fed mice also demonstrated impaired insulin sensitivity(lower QUICKI, higher HOMA-insulin resistance(HOMA-IR), and lower HOMA-percent sensitivity(HOMA-%S)) index values.Conclusion: Male C57 BL/6 J mice on 9 weeks HFD providing 60 kcal energy from fat display impaired insulin sensitivity and chronic inflammation, thus making this DIO mouse model appropriate for studies of early stages of obesity-related pathology.展开更多
Fish oil (mainly omega 3 polyunsaturated fatty acids), differently from lard (mainly saturated fatty acids) has been suggested to have anti-inflammatory effects associated with amelioration of insulin sensibility. An ...Fish oil (mainly omega 3 polyunsaturated fatty acids), differently from lard (mainly saturated fatty acids) has been suggested to have anti-inflammatory effects associated with amelioration of insulin sensibility. An important role in skeletal muscle insulin resistance development has been recently attributed to mitochondrial dynamic behavior. Mitochondria are dynamic organelles that frequently undergo fission/fusion processes and a shift toward fission process has been associated with skeletal muscle mitochondrial dysfunction and insulin resistance development. The present work aimed to evaluate if the replacement of lard with fish oil in high-fat diet positively affect skeletal muscle mitochondrial dynamic behavior in association with the improvement of insulin-resistance. Body weight gain, systemic insulin-resistance (glucose/insulin ratio), serum TNFα levels and skeletal muscle lipid content were assessed in rats fed a high-lard or high-fish-oil diet for 6 weeks. In skeletal muscle sections, immunohistochemical analysis were performed to detect the presence of insulin receptor substrate 1 (IRS1) and tyrosine phosphorylated IRS1 (key factor in insulin signalling pathway) as well as to detect the main proteins involved in mitochondrial fusion (MFN2 and OPA1) and fission (DRP1 and Fis1) processes. Skeletal muscle mitochondrial ultrastructural features were assessed by electron microscopy. High-fish oil feeding induced lower body weight gain, systemic inflammation and insulin-resistance development as well as skeletal muscle lipid accumulation compared to high-lard feeding. Skeletal muscle sections from high-fish oil fed rats exhibited a greater number of immunoreactive fibers for MFN2 and OPA1 proteins as well as weaker immunostaining for DRP1 and Fis1 compared to sections from high-lard fed rats. Electron microscopy observations suggested a prominent presence of fission events in L rats and fusion events in F rats. The positive effect of the replacement of lard with fish oil in high-fat diet on systemic and skeletal muscle insulin sensibility was associated to changes in mitochondrial dynamic behavior.展开更多
目的:探讨RNA m^(6)A甲基化修饰在脂肪细胞胰岛素抵抗中的作用及机制。方法:收集2型糖尿病患者术中赘余皮下脂肪组织,以非2型糖尿病患者同样组织为对照,检测组间RNA m^(6)A水平。高脂饮食诱导C57BL/6J小鼠构建胰岛素抵抗(in⁃sulin resis...目的:探讨RNA m^(6)A甲基化修饰在脂肪细胞胰岛素抵抗中的作用及机制。方法:收集2型糖尿病患者术中赘余皮下脂肪组织,以非2型糖尿病患者同样组织为对照,检测组间RNA m^(6)A水平。高脂饮食诱导C57BL/6J小鼠构建胰岛素抵抗(in⁃sulin resistance,IR)模型(HFD组,n=5,60%高脂饲料喂养16周),对照组10%低脂饲料喂养16周(CD组,n=5)。模型构建成功后,取附睾周围脂肪组织行表观转录组学m^(6)A甲基化修饰芯片检测,并借助MeRIP-qPCR实验、RT-qPCR以及RNA结合蛋白免疫沉淀测定(RNA Binding Protein Immunoprecipitation Assay,RIP)实验验证胰岛素信号转导相关基因变化;进一步观察METTL3小分子抑制剂STM2457对高脂饮食诱导下小鼠胰岛素信号转导基因的影响。结果:2型糖尿病患者和小鼠IR模型脂肪组织中总体m^(6)A修饰水平均升高(患者200 ng RNA t=-8.375,P<0.001;患者100 ng RNA t=-3.722,P=0.006;患者50 ng RNA t=-4.937;P=0.001;小鼠100 ng RNA t=-3.590,P=0.023;小鼠50 ng RNA t=-2.760,P=0.025)。表观转录组学检测证实IR的脂肪组织中1175个基因发生高m^(6)A修饰,55个基因发生低m^(6)A修饰,同时有182个基因呈现高m^(6)A修饰且低表达,包括AKT2、INSR、PIK3R1、ACACA、SREBF1等5个胰岛素信号转导关键基因,其中AKT2、INSR、ACACA、SREBF1等4个基因被确证并证实其与METTL3存在直接结合,其m^(6)A修饰水平受METTL3正向调控。STM2457作用下,胰岛素敏感性提高,且AKT2、INSR、ACACA、SREBF1转录水平上调,提示IR表型改善明显。结论:高脂饮食通过METTL3诱导脂肪细胞胰岛素信号转导基因AKT2、INSR、ACACA、SREBF1发生m^(6)A高甲基化修饰,诱导其低表达,阻滞胰岛素信号转导,进而参与诱发IR。展开更多
Epidemiological data show that the consumption of added sugars as ingredients in processed or prepared foods and caloric beverages has dramatically increased. Fructose and fructose-based sweeteners are the most common...Epidemiological data show that the consumption of added sugars as ingredients in processed or prepared foods and caloric beverages has dramatically increased. Fructose and fructose-based sweeteners are the most commonly added sugars and high-fructose corn syrup (HFCS-55: 55% fructose, 42% glucose and 3% higher saccharides) accounts for over 40% of all added caloric sweeteners. Concerns regarding the health risk of added sugar follow the demonstration that the consumption of foods and beverages high in sugars is associated with an increased prevalence of obesity, insulin resistance, dyslipidemia and, more recently, ischemic heart and kidney diseases. The molecular mechanism(s) underlying the detrimental effects of sugar are not completely understood and their elucidation is critical to provide new insights on the health risk of fructose-based sweeteners. A better understanding of the key role of fructose overconsumption in the development of metabolic disorders may contribute to planning new strategies for preventing deleterious dietary behaviors from becoming established and, thus, curbing the rise in the number of insulin-resistant, obese and diabetic populations worldwide.展开更多
Patients with type 2 diabetes mellitus(T2DM) frequently exhibit macrovascular complications of atherosclerotic cardiovascular(CV) disease. High density lipoproteins(HDL) are protective against atherosclerosis. Low lev...Patients with type 2 diabetes mellitus(T2DM) frequently exhibit macrovascular complications of atherosclerotic cardiovascular(CV) disease. High density lipoproteins(HDL) are protective against atherosclerosis. Low levels of HDL cholesterol(HDL-C) independently contribute to CV risk. Patients with T2 DM not only exhibit low HDL-C, but also dysfunctional HDL. Furthermore, low concentration of HDL may increase the risk for the development of T2 DM through a decreased β cell survival and secretory function. In this paper, we discuss emerging concepts in the relationship of T2 DM with HDL.展开更多
AIM:To investigate the effect of novel probiotics on the clinical characteristics of high-fructose induced metabolic syndrome.METHODS:Male Wistar rats aged 4 wk were fed a 70% w/w high-fructose diet(n = 27) or chow di...AIM:To investigate the effect of novel probiotics on the clinical characteristics of high-fructose induced metabolic syndrome.METHODS:Male Wistar rats aged 4 wk were fed a 70% w/w high-fructose diet(n = 27) or chow diet(n = 9) for 3 wk to induce metabolic syndrome,the rats were then randomized into groups and administered probiotic [Lactobacillus curvatus(L.curvatus) HY7601 and Lactobacillus plantarum(L.plantarum) KY1032] at 109 cfu/d or 1010 cfu/d or placebo by oral gavage for 3 wk.Food intake and body weight were measured once a week.After 6 wk,the rats were fasted for 12 h,then anesthetized with diethyl ether and sacrificed.Blood samples were taken from the inferior vena cava for plasma analysis of glucose,insulin,C-peptide,totalcholesterol,triglycerides and thiobarbituric acid-reacting substances.Real-time polymerase chain reaction was performed using mouse-specific Taqman probe sets to assess genes related to fatty acid β-oxidation,lipogenesis and cholesterol metabolism in the liver.Target gene expression was normalized to the housekeeping gene,glyceraldehyde-3-phosphate dehydrogenase.RESULTS:Rodents fed a high-fructose diet developed clinical characteristics of the metabolic syndrome including increased plasma glucose,insulin,triglycerides,total cholesterol and oxidative stress levels,as well as increased liver mass and liver lipids compared to chow fed controls.Probiotic treatment(L.curvatus HY7601 and L.plantarum KY1032) at high(1010 cfu/d) or low dosage(109 cfu/d) lowered plasma glucose,insulin,triglycerides and oxidative stress levels.Only high-dose probiotic treatment reduced liver mass and liver cholesterol.Probiotic treatment reduced lipogenesis via downregulation of SREBP1,FAS and SCD1 mRNA levels and increased β-oxidation via up-regulation of PPARα and CPT2 mRNA levels.CONCLUSION:Probiotic L.curvatus HY7601 and L.plantarum KY1032 combined suppressed the clinical characteristics of high-fructose-induced metabolic syndrome,therefore,may provide a natural alternative for the treatment of diet-induced metabolic syndrome.展开更多
文摘Background: Type II diabetes mellitus is associated with multiple metabolic derangements which can cause secondary pathophysiological changes in multiple organ systems. This in turn can impose a heavy burden of morbidity and mortality from micro‑ and macro‑vascular complications. This study aimed to describe the metabolic and therapeutic profile of a subgroup of type 2 diabetic patients who have treatment failure with oral anti-hyperglycemic agents with persistent hyperglycemia despite insulin treatment. Methods: 60 type 2 diabetic patients in treatment failure with oral antidiabetics and under insulin treatment, aged 35 to 70 years, were recruited at the Diabetes Clinic of the University Teaching Hospital of Treichville in Abidjan, Côte d’Ivoire. Blood samples were collected in tubes containing Ethylenediaminetetraacetic Acid (EDTA) to determine glycated hemoglobin (HbA1c). Results: The average age of the population was 54 ± 9.38 years with a sex ratio (M/F) of 0.3, an average BMI of 30.25 ± 5 kg/m<sup>2</sup>, and an average HbA1c of 10.1% ± 1.6% for an average diabetes duration of 11.8 ± 5.8 years. The average insulin dose was 74.556 ± 16.21 UI/day, and the average duration of insulin treatment was 5.4 ± 3.1 years. The average HbA1c value was 10.1% ± 1.87% in men against 10.03% ± 1.53% in women with no significant difference (p = 0.1). The mean HbA1c values according to patient weight were 10.08% ± 2.05% for normal weight, 9.55% ± 2.26% for overweight, and 10.57% for obese, with no significant difference between the three groups of patients (p = 0.1). Conclusion: This study showed a persistence increase in glycated hemoglobin regardless of the treatment regimen, duration, and dose of insulin treatment in the subpopulation of type 2 diabetic patients.
基金supported by the National Natural Science Foundation of China(30972439)Bureau of Health Foundation,Heilongjiang Province(2006-300),(2012-768)Youth Fund of School of Public Health,HMU
文摘Female Wister rats aged 8 weeks were randomly divided into sham operation group, ovariectomized (OVX) control group, and 20VX groups fed with soy isoflavone crude extract supplementation. The rats had free access to high fat diet and water for 9 weeks. No significant difference was found in body weight (BW), total abdominal fat, food intake and food utilization rate between OVX control group and 20VX groups. However, the fasting blood glucose and blood lipid levels were significantly higher in 20VX groups than in OVX control group (P〈0.05). Intraperitoneal glucose tolerance test (IGTI") showed that the area under AUC was smaller in 20VX groups than in OVX control group (P〈0.05). These findings showed that soy isoflavone crude extract supplementation can improve glucose tolerance and prevent high fat diet-induced insulin resistance in ovariectomized rats.
文摘AIM:To investigate the effects of mitofusin-2(MFN2) on insulin sensitivity and its potential targets in the liver of rats fed with a high-fat diet(HFD).METHODS:Rats were fed with a control or HFD for 4 or 8 wk,and were then infected with a control or an MFN2 expressing adenovirus once a week for 3wk starting from the 9th wk.Blood glucose(BG),plasma insulin and insulin sensitivity of rats were determined at end of the 4th and 8th wk,and after treatment with different amounts of MFN2 expressing adenovirus(108,109 or 1010 vp/kg body weight).BG levels were measured by Accu-chek Active Meter.Plasma insulin levels were analyzed by using a Rat insulin enzymelinked immunosorbent assay kit.Insulin resistance was evaluated by measuring the glucose infusion rate(GIR) using a hyperinsulinemic euglycemic clamp technique.The expression or phosphorylation levels of MFN2 and essential molecules in the insulin signaling pathway,such as insulin receptor(INSR),insulin receptor substrate 2(IRS2),phosphoinositide-3-kinase(PI3K),protein kinase beta(AKT2) and glucose transporter type 2(GLUT2) was assayed by quantitative real-time polymerase chain reaction and Western-blotting.RESULTS:After the end of 8wk,the body weight of rats receiving the normal control diet(ND) and the HFD was not significantly different(P>0.05).Compared with the ND group,GIR in the HFD group was significantly decreased(P<0.01),while the levels of BG,triglycerides(TG),total cholesterol(TC) and insulin in the HFD group were significantly higher than those in the ND group(P<0.05).Expression of MFN2 mRNA and protein in liver of rats was significantly downregulated in the HFD group(P<0.01) after 8 wk of HFD feeding.The expression of INSR,IRS2 and GLUT2 were down-regulated markedly(P<0.01).Although there were no changes in PI3K-P85 and AKT2 expression,their phosphorylation levels were decreased significantly(P<0.01).After intervention with MFN2 expressing adenovirus for 3wk,the expression of MFN2 mRNA and protein levels were up-regulated(P<0.01).There was no difference in body weight of rats between the groups.The levels of BG,TG,TC and insulin in rats were lower than those in the Ad group(P<0.05),but GIR in rats infected with Ad-MFN2 was significantly increased(P<0.01),compared with the Ad group.The expression of INSR,IRS2 and GLUT2 was increased,while phosphorylation levels of PI3K-P85 and AKT2 were increased(P<0.01),compared with the Ad group.CONCLUSION:HFDs induce insulin resistance,and this can be reversed by MFN2 over-expression targeting the insulin signaling pathway.
基金Gerald J.and Dorothy R.Friedman New York Foundation for Medical Research
文摘Background: Animal models of diet-induced obesity(DIO) are commonly used in medical research for mimicking human diseases. There is no universal animal model, and careful evaluation of variety of factors needs to be considered when designing new experiments. Here, we investigated the effect of 9 weeks high-fat diet(HFD) intervention, providing 60% energy from fat, on parameters of inflammation and insulin resistance in male C57 BL/6 J mice.Methods: Six weeks old mice were initiated on regular diet(RD) or HFD providing 60 kcal energy from fat for 9 weeks. Fasting blood glucose levels were measured by glucometer, and fasting plasma levels of insulin and proinflammatory cytokines by Luminex assay. Insulin sensitivity was evaluated by using QUICKI and HOMA2 indexes.Results: HFD mice showed ~ 40% higher body weight and ~ 20% larger abdominal circumference, due to an increase in the white adipose tissue mass. Liver examination revealed increased size and higher hepatic lipid accumulation in livers from HFD mice compared to their RD counterparts. Animals from the HFD group were characterized with significantly higher presence of crown-like structures(CLS) in WAT and higher plasma levels of proinflammatory cytokines(TNF-α, IL-6, leptin, MCP-1, PAI-1, and resistin). HFD-fed mice also demonstrated impaired insulin sensitivity(lower QUICKI, higher HOMA-insulin resistance(HOMA-IR), and lower HOMA-percent sensitivity(HOMA-%S)) index values.Conclusion: Male C57 BL/6 J mice on 9 weeks HFD providing 60 kcal energy from fat display impaired insulin sensitivity and chronic inflammation, thus making this DIO mouse model appropriate for studies of early stages of obesity-related pathology.
文摘Fish oil (mainly omega 3 polyunsaturated fatty acids), differently from lard (mainly saturated fatty acids) has been suggested to have anti-inflammatory effects associated with amelioration of insulin sensibility. An important role in skeletal muscle insulin resistance development has been recently attributed to mitochondrial dynamic behavior. Mitochondria are dynamic organelles that frequently undergo fission/fusion processes and a shift toward fission process has been associated with skeletal muscle mitochondrial dysfunction and insulin resistance development. The present work aimed to evaluate if the replacement of lard with fish oil in high-fat diet positively affect skeletal muscle mitochondrial dynamic behavior in association with the improvement of insulin-resistance. Body weight gain, systemic insulin-resistance (glucose/insulin ratio), serum TNFα levels and skeletal muscle lipid content were assessed in rats fed a high-lard or high-fish-oil diet for 6 weeks. In skeletal muscle sections, immunohistochemical analysis were performed to detect the presence of insulin receptor substrate 1 (IRS1) and tyrosine phosphorylated IRS1 (key factor in insulin signalling pathway) as well as to detect the main proteins involved in mitochondrial fusion (MFN2 and OPA1) and fission (DRP1 and Fis1) processes. Skeletal muscle mitochondrial ultrastructural features were assessed by electron microscopy. High-fish oil feeding induced lower body weight gain, systemic inflammation and insulin-resistance development as well as skeletal muscle lipid accumulation compared to high-lard feeding. Skeletal muscle sections from high-fish oil fed rats exhibited a greater number of immunoreactive fibers for MFN2 and OPA1 proteins as well as weaker immunostaining for DRP1 and Fis1 compared to sections from high-lard fed rats. Electron microscopy observations suggested a prominent presence of fission events in L rats and fusion events in F rats. The positive effect of the replacement of lard with fish oil in high-fat diet on systemic and skeletal muscle insulin sensibility was associated to changes in mitochondrial dynamic behavior.
文摘目的:探讨RNA m^(6)A甲基化修饰在脂肪细胞胰岛素抵抗中的作用及机制。方法:收集2型糖尿病患者术中赘余皮下脂肪组织,以非2型糖尿病患者同样组织为对照,检测组间RNA m^(6)A水平。高脂饮食诱导C57BL/6J小鼠构建胰岛素抵抗(in⁃sulin resistance,IR)模型(HFD组,n=5,60%高脂饲料喂养16周),对照组10%低脂饲料喂养16周(CD组,n=5)。模型构建成功后,取附睾周围脂肪组织行表观转录组学m^(6)A甲基化修饰芯片检测,并借助MeRIP-qPCR实验、RT-qPCR以及RNA结合蛋白免疫沉淀测定(RNA Binding Protein Immunoprecipitation Assay,RIP)实验验证胰岛素信号转导相关基因变化;进一步观察METTL3小分子抑制剂STM2457对高脂饮食诱导下小鼠胰岛素信号转导基因的影响。结果:2型糖尿病患者和小鼠IR模型脂肪组织中总体m^(6)A修饰水平均升高(患者200 ng RNA t=-8.375,P<0.001;患者100 ng RNA t=-3.722,P=0.006;患者50 ng RNA t=-4.937;P=0.001;小鼠100 ng RNA t=-3.590,P=0.023;小鼠50 ng RNA t=-2.760,P=0.025)。表观转录组学检测证实IR的脂肪组织中1175个基因发生高m^(6)A修饰,55个基因发生低m^(6)A修饰,同时有182个基因呈现高m^(6)A修饰且低表达,包括AKT2、INSR、PIK3R1、ACACA、SREBF1等5个胰岛素信号转导关键基因,其中AKT2、INSR、ACACA、SREBF1等4个基因被确证并证实其与METTL3存在直接结合,其m^(6)A修饰水平受METTL3正向调控。STM2457作用下,胰岛素敏感性提高,且AKT2、INSR、ACACA、SREBF1转录水平上调,提示IR表型改善明显。结论:高脂饮食通过METTL3诱导脂肪细胞胰岛素信号转导基因AKT2、INSR、ACACA、SREBF1发生m^(6)A高甲基化修饰,诱导其低表达,阻滞胰岛素信号转导,进而参与诱发IR。
文摘Epidemiological data show that the consumption of added sugars as ingredients in processed or prepared foods and caloric beverages has dramatically increased. Fructose and fructose-based sweeteners are the most commonly added sugars and high-fructose corn syrup (HFCS-55: 55% fructose, 42% glucose and 3% higher saccharides) accounts for over 40% of all added caloric sweeteners. Concerns regarding the health risk of added sugar follow the demonstration that the consumption of foods and beverages high in sugars is associated with an increased prevalence of obesity, insulin resistance, dyslipidemia and, more recently, ischemic heart and kidney diseases. The molecular mechanism(s) underlying the detrimental effects of sugar are not completely understood and their elucidation is critical to provide new insights on the health risk of fructose-based sweeteners. A better understanding of the key role of fructose overconsumption in the development of metabolic disorders may contribute to planning new strategies for preventing deleterious dietary behaviors from becoming established and, thus, curbing the rise in the number of insulin-resistant, obese and diabetic populations worldwide.
文摘Patients with type 2 diabetes mellitus(T2DM) frequently exhibit macrovascular complications of atherosclerotic cardiovascular(CV) disease. High density lipoproteins(HDL) are protective against atherosclerosis. Low levels of HDL cholesterol(HDL-C) independently contribute to CV risk. Patients with T2 DM not only exhibit low HDL-C, but also dysfunctional HDL. Furthermore, low concentration of HDL may increase the risk for the development of T2 DM through a decreased β cell survival and secretory function. In this paper, we discuss emerging concepts in the relationship of T2 DM with HDL.
基金Supported by The Basic Science Research Program,Center for Food and Nutritional Genomicsthe National Research Foundation(NRF) of Korea funded by the Ministry of Education,Science and Technology,No.2011-0000912Korea Yakult Co., Ltd.
文摘AIM:To investigate the effect of novel probiotics on the clinical characteristics of high-fructose induced metabolic syndrome.METHODS:Male Wistar rats aged 4 wk were fed a 70% w/w high-fructose diet(n = 27) or chow diet(n = 9) for 3 wk to induce metabolic syndrome,the rats were then randomized into groups and administered probiotic [Lactobacillus curvatus(L.curvatus) HY7601 and Lactobacillus plantarum(L.plantarum) KY1032] at 109 cfu/d or 1010 cfu/d or placebo by oral gavage for 3 wk.Food intake and body weight were measured once a week.After 6 wk,the rats were fasted for 12 h,then anesthetized with diethyl ether and sacrificed.Blood samples were taken from the inferior vena cava for plasma analysis of glucose,insulin,C-peptide,totalcholesterol,triglycerides and thiobarbituric acid-reacting substances.Real-time polymerase chain reaction was performed using mouse-specific Taqman probe sets to assess genes related to fatty acid β-oxidation,lipogenesis and cholesterol metabolism in the liver.Target gene expression was normalized to the housekeeping gene,glyceraldehyde-3-phosphate dehydrogenase.RESULTS:Rodents fed a high-fructose diet developed clinical characteristics of the metabolic syndrome including increased plasma glucose,insulin,triglycerides,total cholesterol and oxidative stress levels,as well as increased liver mass and liver lipids compared to chow fed controls.Probiotic treatment(L.curvatus HY7601 and L.plantarum KY1032) at high(1010 cfu/d) or low dosage(109 cfu/d) lowered plasma glucose,insulin,triglycerides and oxidative stress levels.Only high-dose probiotic treatment reduced liver mass and liver cholesterol.Probiotic treatment reduced lipogenesis via downregulation of SREBP1,FAS and SCD1 mRNA levels and increased β-oxidation via up-regulation of PPARα and CPT2 mRNA levels.CONCLUSION:Probiotic L.curvatus HY7601 and L.plantarum KY1032 combined suppressed the clinical characteristics of high-fructose-induced metabolic syndrome,therefore,may provide a natural alternative for the treatment of diet-induced metabolic syndrome.