不同脂肪酸类型对糖耐量正常人群胰岛素敏感性的影响及其机制的研究
|
摘要
2型糖尿病(Type 2 diabetes mellitus,T2DM)的患病率呈快速上升趋势,将成为21世纪全球的新灾难之一,预计到2030年全世界糖尿病患病人数将达到3.66亿,其并发症也在呈直线上升,目前迫切需要寻找一种有效的预防和治疗措施。众所周知,胰岛素抵抗(insulin resistance,IR)是2型糖尿病发生的主要机制之一。
长期高脂饮食的人群IR和2型糖尿病发病率明显高于正常人群,动物实验也证实,高脂环境可以损害包括骨骼肌、肝脏和脂肪在内的多种胰岛素靶器官的胰岛素敏感性。目前认为高脂环境是诱发IR的独立危险因素之一。但是,饮食中的脂肪酸类型可能影响糖尿病的发病率,推测不同的脂肪酸类型可能对胰岛素敏感性产生不同的影响。动物实验显示多不饱和脂肪酸(polyunsaturated fatty acid,PUFA)和饱和脂肪酸( saturated fatty acid,SFA)可能导致IR,而单不饱和脂肪酸(monounsaturated fatty acid,MUFA)和n-3系PUFA可能改善IR。但是,关于不同类型的脂肪酸饮食对胰岛素敏感性的影响,至今国内外说法不一。
随着研究的逐步深入,人们发现胰岛素信号转导障碍、脂肪源性细胞因子分泌异常、氧化应激在IR发生过程中扮演了重要的角色。脂肪组织作为一个内分泌器官,在许多生理过程中起着重要作用,可以分泌肿瘤坏死因子α(tumor necrosis factor alpha, TNF-α)、脂联素(adiponectin,APN)、抵抗素(resistin,RES)、瘦素(leptin,Lep)、白介素-6(interleukin 6,IL-6)、纤维蛋白溶酶原激活物抑制物-1 (plasminogen activator Inhibitor,PAI-1)等因子,以及发现的内脂素(visfatin,VIS)、视黄醇结合蛋白-4(retinol binding protein 4,RBP-4)等多种细胞因子。当前研究显示脂肪细胞因子的分泌紊乱是IR发生、发展过程中的重要机制,脂联素可以改善胰岛素敏感性,而其他的细胞因子可能导致IR。脂肪酸饮食对胰岛素敏感性的影响是否涉及脂肪细胞因子的改变,目前研究不多。
氧化应激是指活性氧簇(reactive oxygen species,ROS)的产生与机体内源性抗氧化防御系统对其的消除能力失去平衡,过多的ROS氧化生物大分子,最终导致细胞损伤。目前对氧化应激参与胰岛素抵抗的机制尚不完全清楚,认为可能与氧化应激时被激活的多种应激敏感通路有关,如核因子-κB(nuclear factor-kappaB,NF-κB)、p38丝裂原活化蛋白激酶(ERK mitogen-activated protein kinases,MAPK)及Jun氨基末端激酶(Jun N-Terminal Kinase,JNK)通路等。各种类型的脂肪酸饮食对氧化应激的影响是否相同,至今报道较少。
内质网(endoplasmic reticulum,ER)广泛存在于真核细胞中,ER可加工合成各种分泌型蛋白和膜蛋白,故其对应激极为敏感,应激状态下ER功能紊乱可破坏内质网稳态,导致未折叠蛋白堆积,产生内质网应激(endoplasmic reticulum stress,ERS)。近来研究认为ERS与肝和脂肪细胞胰岛素抵抗密切相关,因此,一些学者推测ERS可能是导致IR和T2DM的核心机制。ERS激活JNK通路,导致胰岛素受体底物-1(insulin receptor substrate 1,IRS-1)的丝氨酸磷酸化水平升高,损伤胰岛素信号通路,形成胰岛素抵抗。体外实验发现棕榈酸可以诱导ERS但油酸不可,其确切机制尚待进一步研究。
本课题通过对糖耐量正常人群进行不同脂肪酸饮食干预,观察其对胰岛素敏感性的影响,并进一步研究其对氧化应激和脂肪细胞因子的影响,借以探讨其机制。同时,通过对Wistar大鼠进行不同脂肪酸饮食干预,观察其对内质网应激的影响,探讨脂肪酸饮食对胰岛素敏感性的影响机制,为预防IR和T2DM的发生提供理论基础。本研究主要包括以下四部分:
第一部分不同脂肪酸类型对糖耐量正常人群胰岛素敏感性的影响
目的:探讨饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸饮食对糖耐量正常人群胰岛素敏感性的影响。
方法:20例健康受试者分别接受MUFA(M)饮食、PUFA(P)饮食、SFA(S)饮食干预3天,每组饮食干预后行口服葡萄糖耐量试验(oral glucose tolerance test,OGTT),三组饮食间隔期采用标准饮食洗脱1周。三组饮食总热量相同(热量组成:碳水化合物30%,脂肪50%,蛋白质20%),其中MUFA饮食(M组)采用油茶籽油(MUFA:82.3%,PUFA:7.6 %,SFA:9.9%,福临门),PUFA饮食(P组)采用豆油(MUFA:22.3%,PUFA:62.8%,SFA:14.8,福临门),SFA饮食(S组)采用猪油(MUFA:45.6%,PUFA:8.5%,SFA:42.7%,市售),空腹血清测定空腹血糖(FPG)、总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白-胆固醇(LDL-C)、高密度脂蛋白-胆固醇(HDL-C)、极低密度脂蛋白-胆固醇(VLDL)、胰岛素(INS)、C肽,其余各时间点血清分别测定血糖、胰岛素、C肽。
结果:1.与S组相比,M组和P组的FPG显著降低,有统计学意义(P<0.05),但M组和P组之间差异无统计学意义(P>0.05)。其余时间点的血糖三组间差异均无统计学意义(P>0.05)。与S组相比,M组和P组的TC、LDL、apoB显著降低,有统计学意义(P<0.05),但M组和P组之间差异无统计学意义(P>0.05)。而三组间TG、HDL、VLDL、apoA差异均无统计学意义(P>0.05)。2.与M组相比,S组和P组的FINS、HOMA-IR、AUCins、QUCKI、WBISI显著升高,有统计学意义(P<0.01),但S组和P组之间差异无统计学意义(P>0.05)。三组间AUCglu、HOMA-B、△Ins/△FPG差异均无统计学意义(P>0.05)。
结论:1.短期MUFA和PUFA饮食均可以降低空腹血糖和TC、LDL、apoB,说明UFA饮食较SFA饮食更具有抗动脉粥样硬化作用。2.MUFA饮食较PUFA、SFA饮食可以改善胰岛素敏感性,说明MUFA饮食可能更适合糖尿病高危人群及糖尿病病人。
第二部分不同脂肪酸类型对糖耐量正常人群氧化应激的影响
目的:探讨饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸饮食对糖耐量正常人群氧化应激的影响。
方法:受试者选择及标本留取同第一部分。血清丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)测定采用化学比色法,8-异前列腺素F2α(8-iso-PG-F2α)测定采用ELISA方法。
结果:1.与M组相比,S组和P组的MDA、8-iso-PGF2α显著升高,有统计学意义(P<0.01),但S组和P组之间差异无统计学意义(P>0.05)。2.与M组相比,S组和P组的SOD、GSH-PX显著降低,有统计学意义(P<0.01),但S组和P组之间差异无统计学意义(P>0.05)。3. MDA、8-iso-PGF2α与HOMA-IR呈明显正相关(r=0.415和0.443,P<0.05),GSH-PX、SOD与HOMA-IR呈明显负相关(r=-0.327和-0.439,P<0.05)。HOMA-IR与8-iso-PGF2α(r=0.38,P<0.01)独立相关。
结论:1.单不饱和脂肪酸可以改善机体的氧化应激状态。2.尽管多不饱和脂肪酸饮食对空腹血糖和血脂的影响与单不饱和脂肪酸饮食类似,但是可能由于多不饱和脂肪酸容易发生氧化,产生过氧化物,从而导致胰岛素敏感性减低。
第三部分不同脂肪酸类型对糖耐量正常人群脂肪细胞因子的影响目的:探讨饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸饮食对糖耐量正常人群脂肪细胞因子的影响。
方法:受试者选择及标本留取同第一部分。血清脂联素(APN)、肿瘤坏死因子-α(TNF-α)、C反应蛋白(CRP)、内脂素(VIS)和视黄醇结合蛋白-4 (RBP-4)测定采用ELISA方法。游离脂肪酸( FFA)测定采用化学比色法。
结果:1.与M组相比,S组和P组的VIS、APN显著降低,RBP4显著升高,有统计学意义(P<0.05),但S组和P组之间差异无统计学意义(P>0.05)。与S组相比,M组和P组的TNF-α、FFA显著降低,有统计学意义(P<0.05),但M组和P组之间差异无统计学意义(P>0.05)。三组间CRP差异均无统计学意义(P>0.05)。2.TNF-α、RBP4与HOMA-IR呈明显正相关(r=0.423和0.372,P<0.05),VIS、APN与HOMA-IR呈明显负相关(r=-0.458和-0.349,P<0.05)。HOMA-IR与VIS(r=0.34,P<0.01)独立相关。
结论:单不饱和脂肪酸饮食可以降低RBP4、TNF-α,升高VIS、APN水平,可能借此来改善胰岛素抵抗。
第四部分不同脂肪酸类型对大鼠肝脏eIF2α和XBP-1的影响
目的:探讨饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸饮食对大鼠肝脏真核细胞翻译起始子2α(eIF2α)和X盒结合蛋白-1(XBP-1)的影响。
方法:48只大鼠适应性喂养1周后随机分为4组,每组12只,正常对照组(normal control group, N组),实验组分为饱和脂肪酸饮食组(saturated fatty acid diets group, S组)、单不饱和脂肪酸饮食组(monounsaturated fatty acid diets group, M组)、多不饱和脂肪酸饮食组(polyunsaturated fatty acid diets group,P组)。正常对照组给予基础饲料,热量组成为碳水化合物占65.5%,脂肪占10.3%,蛋白质占24.2%;饱和脂肪酸饲料是在基础饲料中添加15%猪油(热量组成为脂肪35.4%,碳水化合物47.2%,蛋白质17.4%);单不饱和脂肪酸饲料是在基础饲料中添加15%茶油(热量组成为脂肪35.4%,碳水化合物47.2%,蛋白质17.4%);多不饱和脂肪酸饲料是在基础饲料中添加15%豆油(热量组成为脂肪35.4%,碳水化合物47.2%,蛋白质17.4%)。所有饲料均由河北医科大学实验动物中心提供。两组每日等热量投喂饲料,每周称体重1次。8周后4组各随机选8只大鼠行高胰岛素-正葡萄糖钳夹试验,同时留取空腹状态血清测定血脂、胰岛素等指标。钳夹实验后喂养3天处死。实验结束后颈动脉放血处死动物,立即取出肝脏组织放入液氮中冷冻,然后保存于-70℃低温冰箱。肝脏XBP-1和p-eIF2α蛋白表达分别用Western Blotting法和免疫组化法测定。
结果:1.实验第8周末,与P、M、S组相比,N组大鼠进食量有所增加,差异有统计学意义(P>0.05)。除外进食量的影响,与S组相比,N、M、P组血清TC、TG降低,差异有统计学意义(P<0.05),而N、M、P三组间无统计学意义(P>0.05)。与N、M组相比,S、P组FINS、FBG升高,差异有统计学意义(P<0.05),GIR明显下降,差异有统计学意义(P<0.05),但S、P两组间无统计学意义(P>0.05)。与N组相比,M组血清FINS、FBG有升高趋势,差异无统计学意义(P>0.05),GIR下降,差异有统计学意义(P<0.05)。2.电镜显示P组和S组大鼠肝脏出现内质网扩张,脱颗粒改变,而M组和N组类似。3. p-elF2α主要在细胞核中表达, P、S组表达较N组、M组显著增多,有统计学意义(P<0.05),但P、S两组间及N、M两组间比较均无统计学意义(P>0.05)。XBP-1在细胞浆和细胞核均有表达,呈棕黄色或棕褐色染色,N组、M组主要在细胞核表达,与之相比,P、S组在细胞浆和细胞核均有表达,但是四组间无统计学意义(P>0.05);Western blot显示XBP-1蛋白相对表达的量分别是:M组(0.85±0.15)、N组(0.79±0.14)、P组(1.09±0.16)、S组(1.15±0.21)。与N、M组比较,P、S组肝脏XBP-1蛋白表达升高,差异有统计学意义(P<0.05);但P、S两组间及N、M两组间比较均无统计学意义(P>0.05)。
结论:1.动物实验中,尽管单不饱和脂肪酸饮食可以减轻胰岛素抵抗,但是与正常对照组相比还是有差异的。说明无论何种脂肪酸饮食,长期高脂饮食可以加重胰岛素抵抗。2.PUFA、SFA组饮食喂养所致大鼠肝脏中XBP-1、p-eIF2α蛋白表达明显高于正常对照和M组,说明ERS可能参与了IR的发生。
Type 2 diabetes is rapidly emerging as one of the greatest global health challenges of the 21st century. The World Health Organization estimates that by the year 2030, 366 million people will be afflicted with diabetes. This looming epidemic is also expected to trigger a steep rise in the complications associated with diabetes. Developing better treatments and novel prevention strategies for type 2 diabetes is therefore a matter of great urgency. It is well known that insulin resistance plays a critical role in the development of type 2 diabetes.
High-fat diets have been shown to produce insulin resistance,animal experiments also prove that high-fat exposure on impaires insulin sensitivity in several insulin target organs, including skeletal muscles, liver, adipocytes etc. Certain fatty acids may have a more deleterious effect on insulin action than others. In animal models, high intake of saturated and polyunsaturated fats induce severe insulin resistance, whereas monounsaturated fats and n-3 fatty acids are less detrimental. However, the relationship between dietary fat acids and insulin sensitivity is not clear, and there are few studies in this field.
With the development of molecular biological technology, many specialists discovered the defects in the insulin signaling pathway, abnormal secretion of adipokines and oxidative stress all contributed to the development of insulin resistance. More and more people realized that adipose tissue was an endocrine organ. Many cytokines secreted by adipocyte such as leptin, adiponectin, tumor necrosis factor alpha (TNF-α), interleukin 6(IL-6), plasminogen activator Inhibitor(PAI-1), resistin, visfatin, and retinol binding protein 4(RBP-4) are all related with the insulin resistant state. The present studies demonstrated that these adipokines performed different actions in IR; adiponectin can improve the insulin sensitivity, while the increase of other cytokines can impair the insulin sensitivity.
Oxidative stress is caused by an imbalance between the production of reactive oxygen and a biological system’s ability to readily detoxify the reactive intermediates or easily repair the resulting damage. It is uncertain that ROS indirectly induce damage to tissues by activating a number of cellular stress-sensitive pathways. These pathways include nuclear factor-kappaB(NF-κB), p38 mitogen-activated protein kinase(MAPK), NH2-terminal Jun kinases/stress-activated protein kinases(JNK), hexosamines, and others.
Endoplasmic reticulum(ER) is a membranous network that functions in the synthesis and processing of secretory and membrane proteins. Certain pathological stress conditions disrupt ER homeostasis and lead to accumulation of unfolded or misfolded proteins in the ER lumen. A recent study has uncovered a link between insulin resistance and endoplasmic reticulum (ER) stress in liver and adipose cells. Therefore, some learners postulated that ER stress is probably a core mechanism involved in triggering insulin resistance and type 2 diabetes. Induction of ER stress leads to hyperactivation of JNK, reduced insulin receptor signaling, systemic insulin resistance and type 2 diabetes. In vivo, palmitate but not oleate induces significant ER stress, but the precise mechanism needs to be further studied.
In the present study, we explore influence of dietary fat acids on insulin sensitivity in healthy adults. Given the link between hepatic cell ER stress and insulin resistance, we examine the effects of chronic FFA treatment on ER stress to provide a new study direction to improve insulin resistance and type 2 diabetes. The paper contains four parts below:
Part one: Effects of dietary fat acids on insulin sensitivity in healthy adults
Objective: To investigate the effects of saturated fats diets, polyunsaturated fats diets and monounsaturated fats diets on insulin sensitivity in healthy adults.
Methods: 20 subjects were recruited from Hebei General Hospital, all subjects were healthy. Each of the three experimental diets was fed for 3 days with a minimum 1-week washout between diets. All subjects completed each of the diets in order. At the end of each 3-day diet period, subjects returned to the clinic for measurement of serum glucose, lipids and insulin sensitivity. The target nutrient composition for all three diets was 30% carbohydrate, 50% fat, 20% protein. Monounsaturated fat acid diet (M) was provided by tea oil, polyunsaturated fat acid diet (P) was provided by soybean oil, Saturated fat acid diet (S) was provided by lard oil.
Results:1. Fasting blood glucose(FBG) in S group adults were higher than that in isocaloric M and P group. Compared with S group, serum total cholesterol(TC), Low-density lipoprotein(LDL) and apolipoprotein B(apoB) were significantly lower in M and P group,but triglyceride(TG),high-density lipoprotein(HDL), very low-density lipoprotein(VLDL) and apolipoprotein A(apoA) in both groups didn’t increase significantly (p>0.05). 2.Compared with M group, Fasting insulin(FINS), Homeostasis Model Assessment insulin resistance index (HOMA-IR), (AUCins) and whole body insulin sensitivity index(QUCKI) were higher in P and S group(p<0.01). There was no detectable difference in AUCglu、HOMA-B、△Ins/△FPG among three groups (p>0.05).
Conclusion: 1.Short-term MUFA-rich and PUFA-rich diets decrease fasting blood glucose and TC, LDL and apoB, which demonstrated that UFA diets may have anti-atherosclerosis effects. 2. MUFA-rich diet improves insulin sensitivity, which probably fits for patients at high risk of diabetes or diabetics.
Part two: Effects of dietary fat acids on oxidative stress in healthy adults
Objective: To observe the effects of saturated fats diets, polyunsaturated fats diets and monounsaturated fats diets on oxidative stress in healthy adults.
Methods: Subjects grouping and the samples acquirement were the same as those in part one. Fasting serum malondialdehyde (MDA),glutathione peroxidase (GSH-PX), and superoxide dismutase (SOD) were measured by Colorimetric method. 8-iso-PG-F2αwas measured by enzyme-linked immunosorbent assay( ELISA).
Results : 1.Compared with M group, MDA and 8-iso-PG-F2αwere significantly higher in S and P group(p<0.01). 2.Compared with M group, SOD and GSH-PX were lower in P and S group(p<0.01), but there was no detectable difference in SOD and GSH-PX between P and S groups (p>0.05). 3. All four markers were significantly associated with HOMA-IR, and 8-iso-PG-F2αwas correlated to HOMA-IR independently.
Conclusion: The present study indicates that ingestion of PUFA and SFA diets could result in an imbalance between oxidant and antioxidant, and thus induce oxidative stress in healthy adults, but MUFA diets can reduce oxidative stress.
Part three: Effects of dietary fat acids on adipocytokines in healthy adults
Objective: To explore the effects of saturated fats diets, polyunsaturated fats diets and monounsaturated fats diets on adipocytokines in healthy adults.
Methods: Subjects grouping and the samples acquirement were the same as those in part one. Samples were analyzed for adiponectin (APN), TNF-α, visfatin (VIS), high-sensitivity C-RP (C-RP), FFA and retinol binding protein 4 (RBP-4). Adiponectin, TNF-α, visfatin, hsC-RP and RBP-4 were analyzed by enzyme-linked immunosorbent assay(ELISA). Free fatty acids (FFA) was measured by Colorimetric method .
Results:1. Compared with M group, the levels of RBP4 were significantly higher in S and P groups, and VIS and APN were significantly lower in S and P groups(p<0.05). 2. Compared with S group, TNF-αand FFA were lower in P and M groups(p<0.01), but there was no detectable difference in TNF-αand FFA between P and M groups (p>0.05). No significantly difference in CRP was observed among three groups (p>0.05). 3. Serum TNF-αand FFA were positvely correlated with HOMA-IR. Serum VIS and APN was negatively correlated with HOMA-IR. Multiple regression analysis showed that visfatin was independent related factors influencing HOMA-IR.
Conclusion: Fasting serum CRP was not detectably affected by alterations in dietary fatty acid profile in healthy adults. MUFA diets improves insulin sensitivity by decreasing RBP4、TNF-αand increasing VIS、APN.
Part four: Effects of dietary fat acids on eIF2αand XBP-1 in liver tissues in rats
Objective: To explore the effects of saturated fats diets, polyunsaturated fats diets and monounsaturated fats diets on eukaryotic initiation factor 2alpha (eIF2α) and X-box binding protein 1(XBP-1) in liver tissues in rats.
Methods: Forty-eight male Wistar rats were randomly divided into normal control (N) group (n=12), saturated fatty acid diets group(S)(n=12), monounsaturated fatty acid diets group(M) (n=12),and polyunsaturated fatty acid diets group(P) (n=12). The rats in control group were fed with a regular low fatty acids diet containing 10.3% fat, 24.2% protein, and 65.5% carbohydrate as percentage of total calories. The rats in M, P and S group were fed regular diets mixed with 15% tea oil, soybean oil, lard oil respectively, containing 35.4% fat, 17.4% protein and 47.2% carbohydrate as percentage of total calories. The rats in every group were fed equal calories every day. The body weights were determined weekly for 8 weeks. The blood sample was collected by cardiac puncture after rats were anesthetized with diethyl ether for the biochemical analysis, insulin resistance was evaluated by glucose infusion rate (GIR) of hyperinsulinemic euglycemic clamp technique. At the end of 8 week, the rats were killed after anesthetized with phenobarbital sodium after hyperinsulinemic euglycemic clamp test, and liver tissues were taken out freeze-clamped with copper clamps precooled in liquid N2 and were stored in -70℃refrigerator. Liver XBP-1 was measured by Western-blot method. The SP immunohischemistry methods were used to detect the distribution changes of p-eIF2αand XBP-1 in the rats liver.
Results:1. Compared with N group, the amount of food intake were significantly lower in S, M and P groups(p<0.05). Adjusted for the amount of food intake, Compared with S group, serum TC, TG were significantly lower in N, M and P groups(p<0.05), but there was no detectable difference in those among N, P and M groups (p>0.05). Compared with N and M groups, FINS and FBG were significantly higher in S and P groups (p<0.05) , GIR was significantly lower in S and P groups (p<0.05). Compared with N group, GIR were significantly lower in M group (p<0.05). 2.The change of liver ultrastructure in P and S groups haved rough endoplasmic reticulum enlargement, taking off grain. The change in M group were nearly the same as those in N group. 3.Immunohistochemistry analysis results showed that cells positive of p-eIF2αwere intense brown staining and localized mainly in cytoblast,cells positive of XBP-1 were intense brown staining and localized both in cytoblast and cytoplasm. Further, western blot for XBP-1 in liver tissues showed that XBP-1 protein levels increased in P and S groups compared with N and M groups(P<0.05).
Conclusions: 1.Long-term high fat diet can lead to insulin resistance,and different kinds of acids may have different impact on insulin sensitivity; diets rich in saturated and polyunsaturated,induce more insulin resistance than other kinds of diets. 2.It may be one of the mechanisms of insulin resistance that PUFA and SFA diets can induce higher expression of XBP-1 and p-eIF2αin liver tissues, simultaneously, which suggested that endoplasmic reticulum stress(ERS) maybe a core mechanism involved in triggering insulin resistance.
长期高脂饮食的人群IR和2型糖尿病发病率明显高于正常人群,动物实验也证实,高脂环境可以损害包括骨骼肌、肝脏和脂肪在内的多种胰岛素靶器官的胰岛素敏感性。目前认为高脂环境是诱发IR的独立危险因素之一。但是,饮食中的脂肪酸类型可能影响糖尿病的发病率,推测不同的脂肪酸类型可能对胰岛素敏感性产生不同的影响。动物实验显示多不饱和脂肪酸(polyunsaturated fatty acid,PUFA)和饱和脂肪酸( saturated fatty acid,SFA)可能导致IR,而单不饱和脂肪酸(monounsaturated fatty acid,MUFA)和n-3系PUFA可能改善IR。但是,关于不同类型的脂肪酸饮食对胰岛素敏感性的影响,至今国内外说法不一。
随着研究的逐步深入,人们发现胰岛素信号转导障碍、脂肪源性细胞因子分泌异常、氧化应激在IR发生过程中扮演了重要的角色。脂肪组织作为一个内分泌器官,在许多生理过程中起着重要作用,可以分泌肿瘤坏死因子α(tumor necrosis factor alpha, TNF-α)、脂联素(adiponectin,APN)、抵抗素(resistin,RES)、瘦素(leptin,Lep)、白介素-6(interleukin 6,IL-6)、纤维蛋白溶酶原激活物抑制物-1 (plasminogen activator Inhibitor,PAI-1)等因子,以及发现的内脂素(visfatin,VIS)、视黄醇结合蛋白-4(retinol binding protein 4,RBP-4)等多种细胞因子。当前研究显示脂肪细胞因子的分泌紊乱是IR发生、发展过程中的重要机制,脂联素可以改善胰岛素敏感性,而其他的细胞因子可能导致IR。脂肪酸饮食对胰岛素敏感性的影响是否涉及脂肪细胞因子的改变,目前研究不多。
氧化应激是指活性氧簇(reactive oxygen species,ROS)的产生与机体内源性抗氧化防御系统对其的消除能力失去平衡,过多的ROS氧化生物大分子,最终导致细胞损伤。目前对氧化应激参与胰岛素抵抗的机制尚不完全清楚,认为可能与氧化应激时被激活的多种应激敏感通路有关,如核因子-κB(nuclear factor-kappaB,NF-κB)、p38丝裂原活化蛋白激酶(ERK mitogen-activated protein kinases,MAPK)及Jun氨基末端激酶(Jun N-Terminal Kinase,JNK)通路等。各种类型的脂肪酸饮食对氧化应激的影响是否相同,至今报道较少。
内质网(endoplasmic reticulum,ER)广泛存在于真核细胞中,ER可加工合成各种分泌型蛋白和膜蛋白,故其对应激极为敏感,应激状态下ER功能紊乱可破坏内质网稳态,导致未折叠蛋白堆积,产生内质网应激(endoplasmic reticulum stress,ERS)。近来研究认为ERS与肝和脂肪细胞胰岛素抵抗密切相关,因此,一些学者推测ERS可能是导致IR和T2DM的核心机制。ERS激活JNK通路,导致胰岛素受体底物-1(insulin receptor substrate 1,IRS-1)的丝氨酸磷酸化水平升高,损伤胰岛素信号通路,形成胰岛素抵抗。体外实验发现棕榈酸可以诱导ERS但油酸不可,其确切机制尚待进一步研究。
本课题通过对糖耐量正常人群进行不同脂肪酸饮食干预,观察其对胰岛素敏感性的影响,并进一步研究其对氧化应激和脂肪细胞因子的影响,借以探讨其机制。同时,通过对Wistar大鼠进行不同脂肪酸饮食干预,观察其对内质网应激的影响,探讨脂肪酸饮食对胰岛素敏感性的影响机制,为预防IR和T2DM的发生提供理论基础。本研究主要包括以下四部分:
第一部分不同脂肪酸类型对糖耐量正常人群胰岛素敏感性的影响
目的:探讨饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸饮食对糖耐量正常人群胰岛素敏感性的影响。
方法:20例健康受试者分别接受MUFA(M)饮食、PUFA(P)饮食、SFA(S)饮食干预3天,每组饮食干预后行口服葡萄糖耐量试验(oral glucose tolerance test,OGTT),三组饮食间隔期采用标准饮食洗脱1周。三组饮食总热量相同(热量组成:碳水化合物30%,脂肪50%,蛋白质20%),其中MUFA饮食(M组)采用油茶籽油(MUFA:82.3%,PUFA:7.6 %,SFA:9.9%,福临门),PUFA饮食(P组)采用豆油(MUFA:22.3%,PUFA:62.8%,SFA:14.8,福临门),SFA饮食(S组)采用猪油(MUFA:45.6%,PUFA:8.5%,SFA:42.7%,市售),空腹血清测定空腹血糖(FPG)、总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白-胆固醇(LDL-C)、高密度脂蛋白-胆固醇(HDL-C)、极低密度脂蛋白-胆固醇(VLDL)、胰岛素(INS)、C肽,其余各时间点血清分别测定血糖、胰岛素、C肽。
结果:1.与S组相比,M组和P组的FPG显著降低,有统计学意义(P<0.05),但M组和P组之间差异无统计学意义(P>0.05)。其余时间点的血糖三组间差异均无统计学意义(P>0.05)。与S组相比,M组和P组的TC、LDL、apoB显著降低,有统计学意义(P<0.05),但M组和P组之间差异无统计学意义(P>0.05)。而三组间TG、HDL、VLDL、apoA差异均无统计学意义(P>0.05)。2.与M组相比,S组和P组的FINS、HOMA-IR、AUCins、QUCKI、WBISI显著升高,有统计学意义(P<0.01),但S组和P组之间差异无统计学意义(P>0.05)。三组间AUCglu、HOMA-B、△Ins/△FPG差异均无统计学意义(P>0.05)。
结论:1.短期MUFA和PUFA饮食均可以降低空腹血糖和TC、LDL、apoB,说明UFA饮食较SFA饮食更具有抗动脉粥样硬化作用。2.MUFA饮食较PUFA、SFA饮食可以改善胰岛素敏感性,说明MUFA饮食可能更适合糖尿病高危人群及糖尿病病人。
第二部分不同脂肪酸类型对糖耐量正常人群氧化应激的影响
目的:探讨饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸饮食对糖耐量正常人群氧化应激的影响。
方法:受试者选择及标本留取同第一部分。血清丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)测定采用化学比色法,8-异前列腺素F2α(8-iso-PG-F2α)测定采用ELISA方法。
结果:1.与M组相比,S组和P组的MDA、8-iso-PGF2α显著升高,有统计学意义(P<0.01),但S组和P组之间差异无统计学意义(P>0.05)。2.与M组相比,S组和P组的SOD、GSH-PX显著降低,有统计学意义(P<0.01),但S组和P组之间差异无统计学意义(P>0.05)。3. MDA、8-iso-PGF2α与HOMA-IR呈明显正相关(r=0.415和0.443,P<0.05),GSH-PX、SOD与HOMA-IR呈明显负相关(r=-0.327和-0.439,P<0.05)。HOMA-IR与8-iso-PGF2α(r=0.38,P<0.01)独立相关。
结论:1.单不饱和脂肪酸可以改善机体的氧化应激状态。2.尽管多不饱和脂肪酸饮食对空腹血糖和血脂的影响与单不饱和脂肪酸饮食类似,但是可能由于多不饱和脂肪酸容易发生氧化,产生过氧化物,从而导致胰岛素敏感性减低。
第三部分不同脂肪酸类型对糖耐量正常人群脂肪细胞因子的影响目的:探讨饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸饮食对糖耐量正常人群脂肪细胞因子的影响。
方法:受试者选择及标本留取同第一部分。血清脂联素(APN)、肿瘤坏死因子-α(TNF-α)、C反应蛋白(CRP)、内脂素(VIS)和视黄醇结合蛋白-4 (RBP-4)测定采用ELISA方法。游离脂肪酸( FFA)测定采用化学比色法。
结果:1.与M组相比,S组和P组的VIS、APN显著降低,RBP4显著升高,有统计学意义(P<0.05),但S组和P组之间差异无统计学意义(P>0.05)。与S组相比,M组和P组的TNF-α、FFA显著降低,有统计学意义(P<0.05),但M组和P组之间差异无统计学意义(P>0.05)。三组间CRP差异均无统计学意义(P>0.05)。2.TNF-α、RBP4与HOMA-IR呈明显正相关(r=0.423和0.372,P<0.05),VIS、APN与HOMA-IR呈明显负相关(r=-0.458和-0.349,P<0.05)。HOMA-IR与VIS(r=0.34,P<0.01)独立相关。
结论:单不饱和脂肪酸饮食可以降低RBP4、TNF-α,升高VIS、APN水平,可能借此来改善胰岛素抵抗。
第四部分不同脂肪酸类型对大鼠肝脏eIF2α和XBP-1的影响
目的:探讨饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸饮食对大鼠肝脏真核细胞翻译起始子2α(eIF2α)和X盒结合蛋白-1(XBP-1)的影响。
方法:48只大鼠适应性喂养1周后随机分为4组,每组12只,正常对照组(normal control group, N组),实验组分为饱和脂肪酸饮食组(saturated fatty acid diets group, S组)、单不饱和脂肪酸饮食组(monounsaturated fatty acid diets group, M组)、多不饱和脂肪酸饮食组(polyunsaturated fatty acid diets group,P组)。正常对照组给予基础饲料,热量组成为碳水化合物占65.5%,脂肪占10.3%,蛋白质占24.2%;饱和脂肪酸饲料是在基础饲料中添加15%猪油(热量组成为脂肪35.4%,碳水化合物47.2%,蛋白质17.4%);单不饱和脂肪酸饲料是在基础饲料中添加15%茶油(热量组成为脂肪35.4%,碳水化合物47.2%,蛋白质17.4%);多不饱和脂肪酸饲料是在基础饲料中添加15%豆油(热量组成为脂肪35.4%,碳水化合物47.2%,蛋白质17.4%)。所有饲料均由河北医科大学实验动物中心提供。两组每日等热量投喂饲料,每周称体重1次。8周后4组各随机选8只大鼠行高胰岛素-正葡萄糖钳夹试验,同时留取空腹状态血清测定血脂、胰岛素等指标。钳夹实验后喂养3天处死。实验结束后颈动脉放血处死动物,立即取出肝脏组织放入液氮中冷冻,然后保存于-70℃低温冰箱。肝脏XBP-1和p-eIF2α蛋白表达分别用Western Blotting法和免疫组化法测定。
结果:1.实验第8周末,与P、M、S组相比,N组大鼠进食量有所增加,差异有统计学意义(P>0.05)。除外进食量的影响,与S组相比,N、M、P组血清TC、TG降低,差异有统计学意义(P<0.05),而N、M、P三组间无统计学意义(P>0.05)。与N、M组相比,S、P组FINS、FBG升高,差异有统计学意义(P<0.05),GIR明显下降,差异有统计学意义(P<0.05),但S、P两组间无统计学意义(P>0.05)。与N组相比,M组血清FINS、FBG有升高趋势,差异无统计学意义(P>0.05),GIR下降,差异有统计学意义(P<0.05)。2.电镜显示P组和S组大鼠肝脏出现内质网扩张,脱颗粒改变,而M组和N组类似。3. p-elF2α主要在细胞核中表达, P、S组表达较N组、M组显著增多,有统计学意义(P<0.05),但P、S两组间及N、M两组间比较均无统计学意义(P>0.05)。XBP-1在细胞浆和细胞核均有表达,呈棕黄色或棕褐色染色,N组、M组主要在细胞核表达,与之相比,P、S组在细胞浆和细胞核均有表达,但是四组间无统计学意义(P>0.05);Western blot显示XBP-1蛋白相对表达的量分别是:M组(0.85±0.15)、N组(0.79±0.14)、P组(1.09±0.16)、S组(1.15±0.21)。与N、M组比较,P、S组肝脏XBP-1蛋白表达升高,差异有统计学意义(P<0.05);但P、S两组间及N、M两组间比较均无统计学意义(P>0.05)。
结论:1.动物实验中,尽管单不饱和脂肪酸饮食可以减轻胰岛素抵抗,但是与正常对照组相比还是有差异的。说明无论何种脂肪酸饮食,长期高脂饮食可以加重胰岛素抵抗。2.PUFA、SFA组饮食喂养所致大鼠肝脏中XBP-1、p-eIF2α蛋白表达明显高于正常对照和M组,说明ERS可能参与了IR的发生。
Type 2 diabetes is rapidly emerging as one of the greatest global health challenges of the 21st century. The World Health Organization estimates that by the year 2030, 366 million people will be afflicted with diabetes. This looming epidemic is also expected to trigger a steep rise in the complications associated with diabetes. Developing better treatments and novel prevention strategies for type 2 diabetes is therefore a matter of great urgency. It is well known that insulin resistance plays a critical role in the development of type 2 diabetes.
High-fat diets have been shown to produce insulin resistance,animal experiments also prove that high-fat exposure on impaires insulin sensitivity in several insulin target organs, including skeletal muscles, liver, adipocytes etc. Certain fatty acids may have a more deleterious effect on insulin action than others. In animal models, high intake of saturated and polyunsaturated fats induce severe insulin resistance, whereas monounsaturated fats and n-3 fatty acids are less detrimental. However, the relationship between dietary fat acids and insulin sensitivity is not clear, and there are few studies in this field.
With the development of molecular biological technology, many specialists discovered the defects in the insulin signaling pathway, abnormal secretion of adipokines and oxidative stress all contributed to the development of insulin resistance. More and more people realized that adipose tissue was an endocrine organ. Many cytokines secreted by adipocyte such as leptin, adiponectin, tumor necrosis factor alpha (TNF-α), interleukin 6(IL-6), plasminogen activator Inhibitor(PAI-1), resistin, visfatin, and retinol binding protein 4(RBP-4) are all related with the insulin resistant state. The present studies demonstrated that these adipokines performed different actions in IR; adiponectin can improve the insulin sensitivity, while the increase of other cytokines can impair the insulin sensitivity.
Oxidative stress is caused by an imbalance between the production of reactive oxygen and a biological system’s ability to readily detoxify the reactive intermediates or easily repair the resulting damage. It is uncertain that ROS indirectly induce damage to tissues by activating a number of cellular stress-sensitive pathways. These pathways include nuclear factor-kappaB(NF-κB), p38 mitogen-activated protein kinase(MAPK), NH2-terminal Jun kinases/stress-activated protein kinases(JNK), hexosamines, and others.
Endoplasmic reticulum(ER) is a membranous network that functions in the synthesis and processing of secretory and membrane proteins. Certain pathological stress conditions disrupt ER homeostasis and lead to accumulation of unfolded or misfolded proteins in the ER lumen. A recent study has uncovered a link between insulin resistance and endoplasmic reticulum (ER) stress in liver and adipose cells. Therefore, some learners postulated that ER stress is probably a core mechanism involved in triggering insulin resistance and type 2 diabetes. Induction of ER stress leads to hyperactivation of JNK, reduced insulin receptor signaling, systemic insulin resistance and type 2 diabetes. In vivo, palmitate but not oleate induces significant ER stress, but the precise mechanism needs to be further studied.
In the present study, we explore influence of dietary fat acids on insulin sensitivity in healthy adults. Given the link between hepatic cell ER stress and insulin resistance, we examine the effects of chronic FFA treatment on ER stress to provide a new study direction to improve insulin resistance and type 2 diabetes. The paper contains four parts below:
Part one: Effects of dietary fat acids on insulin sensitivity in healthy adults
Objective: To investigate the effects of saturated fats diets, polyunsaturated fats diets and monounsaturated fats diets on insulin sensitivity in healthy adults.
Methods: 20 subjects were recruited from Hebei General Hospital, all subjects were healthy. Each of the three experimental diets was fed for 3 days with a minimum 1-week washout between diets. All subjects completed each of the diets in order. At the end of each 3-day diet period, subjects returned to the clinic for measurement of serum glucose, lipids and insulin sensitivity. The target nutrient composition for all three diets was 30% carbohydrate, 50% fat, 20% protein. Monounsaturated fat acid diet (M) was provided by tea oil, polyunsaturated fat acid diet (P) was provided by soybean oil, Saturated fat acid diet (S) was provided by lard oil.
Results:1. Fasting blood glucose(FBG) in S group adults were higher than that in isocaloric M and P group. Compared with S group, serum total cholesterol(TC), Low-density lipoprotein(LDL) and apolipoprotein B(apoB) were significantly lower in M and P group,but triglyceride(TG),high-density lipoprotein(HDL), very low-density lipoprotein(VLDL) and apolipoprotein A(apoA) in both groups didn’t increase significantly (p>0.05). 2.Compared with M group, Fasting insulin(FINS), Homeostasis Model Assessment insulin resistance index (HOMA-IR), (AUCins) and whole body insulin sensitivity index(QUCKI) were higher in P and S group(p<0.01). There was no detectable difference in AUCglu、HOMA-B、△Ins/△FPG among three groups (p>0.05).
Conclusion: 1.Short-term MUFA-rich and PUFA-rich diets decrease fasting blood glucose and TC, LDL and apoB, which demonstrated that UFA diets may have anti-atherosclerosis effects. 2. MUFA-rich diet improves insulin sensitivity, which probably fits for patients at high risk of diabetes or diabetics.
Part two: Effects of dietary fat acids on oxidative stress in healthy adults
Objective: To observe the effects of saturated fats diets, polyunsaturated fats diets and monounsaturated fats diets on oxidative stress in healthy adults.
Methods: Subjects grouping and the samples acquirement were the same as those in part one. Fasting serum malondialdehyde (MDA),glutathione peroxidase (GSH-PX), and superoxide dismutase (SOD) were measured by Colorimetric method. 8-iso-PG-F2αwas measured by enzyme-linked immunosorbent assay( ELISA).
Results : 1.Compared with M group, MDA and 8-iso-PG-F2αwere significantly higher in S and P group(p<0.01). 2.Compared with M group, SOD and GSH-PX were lower in P and S group(p<0.01), but there was no detectable difference in SOD and GSH-PX between P and S groups (p>0.05). 3. All four markers were significantly associated with HOMA-IR, and 8-iso-PG-F2αwas correlated to HOMA-IR independently.
Conclusion: The present study indicates that ingestion of PUFA and SFA diets could result in an imbalance between oxidant and antioxidant, and thus induce oxidative stress in healthy adults, but MUFA diets can reduce oxidative stress.
Part three: Effects of dietary fat acids on adipocytokines in healthy adults
Objective: To explore the effects of saturated fats diets, polyunsaturated fats diets and monounsaturated fats diets on adipocytokines in healthy adults.
Methods: Subjects grouping and the samples acquirement were the same as those in part one. Samples were analyzed for adiponectin (APN), TNF-α, visfatin (VIS), high-sensitivity C-RP (C-RP), FFA and retinol binding protein 4 (RBP-4). Adiponectin, TNF-α, visfatin, hsC-RP and RBP-4 were analyzed by enzyme-linked immunosorbent assay(ELISA). Free fatty acids (FFA) was measured by Colorimetric method .
Results:1. Compared with M group, the levels of RBP4 were significantly higher in S and P groups, and VIS and APN were significantly lower in S and P groups(p<0.05). 2. Compared with S group, TNF-αand FFA were lower in P and M groups(p<0.01), but there was no detectable difference in TNF-αand FFA between P and M groups (p>0.05). No significantly difference in CRP was observed among three groups (p>0.05). 3. Serum TNF-αand FFA were positvely correlated with HOMA-IR. Serum VIS and APN was negatively correlated with HOMA-IR. Multiple regression analysis showed that visfatin was independent related factors influencing HOMA-IR.
Conclusion: Fasting serum CRP was not detectably affected by alterations in dietary fatty acid profile in healthy adults. MUFA diets improves insulin sensitivity by decreasing RBP4、TNF-αand increasing VIS、APN.
Part four: Effects of dietary fat acids on eIF2αand XBP-1 in liver tissues in rats
Objective: To explore the effects of saturated fats diets, polyunsaturated fats diets and monounsaturated fats diets on eukaryotic initiation factor 2alpha (eIF2α) and X-box binding protein 1(XBP-1) in liver tissues in rats.
Methods: Forty-eight male Wistar rats were randomly divided into normal control (N) group (n=12), saturated fatty acid diets group(S)(n=12), monounsaturated fatty acid diets group(M) (n=12),and polyunsaturated fatty acid diets group(P) (n=12). The rats in control group were fed with a regular low fatty acids diet containing 10.3% fat, 24.2% protein, and 65.5% carbohydrate as percentage of total calories. The rats in M, P and S group were fed regular diets mixed with 15% tea oil, soybean oil, lard oil respectively, containing 35.4% fat, 17.4% protein and 47.2% carbohydrate as percentage of total calories. The rats in every group were fed equal calories every day. The body weights were determined weekly for 8 weeks. The blood sample was collected by cardiac puncture after rats were anesthetized with diethyl ether for the biochemical analysis, insulin resistance was evaluated by glucose infusion rate (GIR) of hyperinsulinemic euglycemic clamp technique. At the end of 8 week, the rats were killed after anesthetized with phenobarbital sodium after hyperinsulinemic euglycemic clamp test, and liver tissues were taken out freeze-clamped with copper clamps precooled in liquid N2 and were stored in -70℃refrigerator. Liver XBP-1 was measured by Western-blot method. The SP immunohischemistry methods were used to detect the distribution changes of p-eIF2αand XBP-1 in the rats liver.
Results:1. Compared with N group, the amount of food intake were significantly lower in S, M and P groups(p<0.05). Adjusted for the amount of food intake, Compared with S group, serum TC, TG were significantly lower in N, M and P groups(p<0.05), but there was no detectable difference in those among N, P and M groups (p>0.05). Compared with N and M groups, FINS and FBG were significantly higher in S and P groups (p<0.05) , GIR was significantly lower in S and P groups (p<0.05). Compared with N group, GIR were significantly lower in M group (p<0.05). 2.The change of liver ultrastructure in P and S groups haved rough endoplasmic reticulum enlargement, taking off grain. The change in M group were nearly the same as those in N group. 3.Immunohistochemistry analysis results showed that cells positive of p-eIF2αwere intense brown staining and localized mainly in cytoblast,cells positive of XBP-1 were intense brown staining and localized both in cytoblast and cytoplasm. Further, western blot for XBP-1 in liver tissues showed that XBP-1 protein levels increased in P and S groups compared with N and M groups(P<0.05).
Conclusions: 1.Long-term high fat diet can lead to insulin resistance,and different kinds of acids may have different impact on insulin sensitivity; diets rich in saturated and polyunsaturated,induce more insulin resistance than other kinds of diets. 2.It may be one of the mechanisms of insulin resistance that PUFA and SFA diets can induce higher expression of XBP-1 and p-eIF2αin liver tissues, simultaneously, which suggested that endoplasmic reticulum stress(ERS) maybe a core mechanism involved in triggering insulin resistance.
引文
1 Manco M, Calvani M, Mingrone G. Effects of dietary fatty acids on insulin sensitivity and secretion. Diabetes Obes Metab, 2004, 6(6): 402-13
2 Parker DR, Weiss ST, Troisi R, et al. Relationship of dietary saturated fatty acids and body habitus to serum insulin concentrations: the Normative Aging Study. Am J Clin Nutr, 1993, 58(2): 129-36
3 Vessby B, Unsitupa M, Hermansen K, et al. Substituting dietary saturated for monounsaturated fat impairs insulin sensitivity in healthy men and women: The KANWU Study. Diabetologia, 2001, 44(3): 312-9
4 Meyer KA, Kushi LH, Jacobs DR Jr, et al. Dietary fat and incidence of type 2 diabetes in older Iowa women. Diabetes Care, 2001, 24(9):1528-35
5 Flachs P, Mohamed-Ali V, Horakova O, et al. Polyunsaturated fatty acids of marine origin induce adiponectin in mice fed a high-fat diet. Diabetologia, 2006, 49(2): 394-7
6 Sailaja JB, Balasubramaniyan V, Nalini N. Effect of exogenous leptin administration on high fat diet induced oxidative stress. Pharmazie, 2004,59(6): 475-9
7 Ozcan U, Yilmaz E, Ozcan L, et al. Chemical chaperones reduce ER stress and restore glucose homeostasis in a mouse model of type 2 diabetes. Science, 2006, 313(5790): 1137-40
8 Gorlach A, Klappa P, Kietzmann T. The endoplasmic reticulum: folding, calcium homeostasis, signaling, and redox control. Antioxid Redox Signal, 2006,8(9-10):1391-418
9 Chakravarthi S, Jessop CE, Bulleid NJ. The role of glutathione in disulphide bond formation and endoplasmic-reticulum-generated oxidative stress. EMBO Rep, 2006, 7(3):271-5
10 Fedoroff N. Redox regulatory mechanisms in cellular stress responses. Ann Bot (Lond), 2006,98(2):289-300
11 Karaskov E, Scott C, Zhang L, et al. Chronic palmitate but not oleate exposure induces endoplasmic reticulum stress, which may contribute to INS-1 pancreatic beta-cell apoptosis. Endocrinology, 2006, 147(7): 3398-407
1 Manco M, Calvani M, Mingrone G. Effects of dietary fatty acids oninsulin sensitivity and secretion. Diabetes Obes Metab, 2004,6(6):402-13
2 van Dam RM, Willett WC, Rimm EB, et al. Dietary fat and meat intake in relation to risk of type 2 diabetes in men. Diabetes Care, 2002,25(3):417-24
3 Meyer KA, Kushi LH, Jacobs DR Jr, et al. Dietary fat and incidence of type 2 diabetes in older Iowa women. Diabetes Care, 2001,24(9):1528-35
4 Thanopoulou AC, Karamanos BG, Angelico FV, et al. Dietary fat intake as risk factor for the development of diabetes: multinational, multicenter study of the Mediterranean Group for the Study of Diabetes (MGSD). Diabetes Care, 2003,26(2):302-7
5 Vessby B, Unsitupa M, Hermansen K, et al. Substituting dietary saturated for monounsaturated fat impairs insulin sensitivity in healthy men and women: The KANWU Study. Diabetologia, 2001,44(3):312-9
6 Fung TT, Rexrode KM, Mantzoros CS, et al. Mediterranean diet and incidence of and mortality from coronary heart disease and stroke in women. Circulation, 2009,119(8):1093-100
7 Martinez-Gonzalez MA, de la Fuente-Arrillaga C, Nunez-Cordoba JM, et al. Adherence to Mediterranean diet and risk of developing diabetes: prospective cohort study. BMJ, 2008,336(7657):1348-51
8 DeFronzo RA, Tobin JD, Andres R. Glucose clamp technique: a method for quantifying insulin secretion and resistance. Am J Physiol, 1979,237(3):E214-23
9 Pacini G, Bergman RN. MINMOD: a computer program to calculate insulin sensitivity and pancreatic responsivity from the frequently sampled intravenous glucose tolerance test. Comput Methods Programs Biomed, 1986,23(2):113-22
10 Matsuda M, DeFronzo RA. Insulin sensitivity indices obtained from oral glucose tolerance testing: comparison with the euglycemic insulin clamp. Diabetes Care, 1999,22(9):1462-70
11 Coll T, Eyre E, Rodriguez-Calvo R, et al. Oleate reverses palmitate-induced insulin resistance and inflammation in skeletal musclecells. J Biol Chem, 2008,283(17):11107-16
12 Davis JE, Gabler NK, Walker-Daniels J, et al. The c-Jun N-Terminal Kinase Mediates the Induction of Oxidative Stress and Insulin Resistance by Palmitate and Toll-like Receptor 2 and 4 Ligands in 3T3-L1 Adipocytes. Horm Metab Res, 2009
13 Perez-Jimenez F, Lopez-Miranda J, Pinillos MD, et al. A Mediterranean and a high-carbohydrate diet improve glucose metabolism in healthy young persons. Diabetologia, 2001,44(11):2038-43
14 Bayindir O, Ozmen D, Mutaf I, et al. Comparison of the effects of dietary saturated, mono-, and n-6 polyunsaturated fatty acids on blood lipid profile, oxidant stress, prostanoid synthesis and aortic histology in rabbits. Ann Nutr Metab, 2002,46(5):222-8
15 Lee JY, Sohn KH, Rhee SH, et al. Saturated fatty acids, but not unsaturated fatty acids, induce the expression of cyclooxygenase-2 mediated through Toll-like receptor 4. J Biol Chem, 2001, 276(20): 16683-9
16宋光耀,高宇,周宇.高饱和脂肪酸、高不饱和脂肪酸、高糖不同饮食诱导高血压伴胰岛素抵抗大鼠的研究.中国病理生理杂志, 2006, 22(11):2270-2273
1 Song F, Jia W, Yao Y, et al. Oxidative stress, antioxidant status and DNA damage in patients with impaired glucose regulation and newlydiagnosed Type 2 diabetes. Clin Sci (Lond), 2007,112(12):599-606
2 Allard JP, Aghdassi E, Mohammed S, et al. Nutritional assessment and hepatic fatty acid composition in non-alcoholic fatty liver disease (NAFLD): a cross-sectional study. J Hepatol, 2008,48(2):300-7
3 Haber CA, Lam TK, Yu Z, et al. N-acetylcysteine and taurine prevent hyperglycemia-induced insulin resistance in vivo: possible role of oxidative stress. Am J Physiol Endocrinol Metab, 2003,285(4):E744-53
4 Henriksen EJ. Exercise training and the antioxidant alpha-lipoic acid in the treatment of insulin resistance and type 2 diabetes. Free Radic Biol Med, 2006,40(1):3-12
5 Morrow JD. Quantification of isoprostanes as indices of oxidant stress and the risk of atherosclerosis in humans. Arterioscler Thromb Vasc Biol, 2005,25(2):279-86
6 Machado MV, Ravasco P, Jesus L, et al. Blood oxidative stress markers in non-alcoholic steatohepatitis and how it correlates with diet. Scand J Gastroenterol, 2008,43(1):95-102
7 Davis JE, Gabler NK, Walker-Daniels J, et al. The c-Jun N-Terminal Kinase Mediates the Induction of Oxidative Stress and Insulin Resistance by Palmitate and Toll-like Receptor 2 and 4 Ligands in 3T3-L1 Adipocytes. Horm Metab Res, 2009, Epub ahead of print
8 Colette C, Percheron C, Pares-Herbute N, et al. Exchanging carbohydrates for monounsaturated fats in energy-restricted diets: effects on metabolic profile and other cardiovascular risk factors. Int J Obes Relat Metab Disord, 2003,27(6):648-56
9 Pinotti MF, Silva MD, Sugizaki MM, et al. Influences of rich in saturated and unsaturated fatty acids diets in rat myocardium. Arq Bras Cardiol, 2007,88(3):346-53
10 Song BJ, Moon KH, Olsson NU, et al. Prevention of alcoholic fatty liver and mitochondrial dysfunction in the rat by long-chain polyunsaturated fatty acids. J Hepatol, 2008,49(2):262-73
11 Yuan M, Konstantopoulos N, Lee J, et al. Reversal of obesity- anddiet-induced insulin resistance with salicylates or targeted disruption of Ikkbeta. Science, 2001,293(5535):1673-7
12 Leslie NR. The redox regulation of PI 3-kinase-dependent signaling. Antioxid Redox Signal, 2006,8(9-10):1765-74
1 Fukuhara A, Matsuda M, Nishizawa M, et al. Visfatin: a protein secreted by visceral fat that mimics the effects of insulin. Science, 2005,307(5708):426-30
2 Yang Q, Graham TE, Mody N, et al. Serum retinol binding protein 4 contributes to insulin resistance in obesity and type 2 diabetes. Nature, 2005,436(7049):356-62
3 Li L, Yang G, Li Q, et al. Changes and relations of circulating visfatin,apelin, and resistin levels in normal, impaired glucose tolerance, and type
2 diabetic subjects. Exp Clin Endocrinol Diabetes, 2006,114(10):544-8
4 Chen MP, Chung FM, Chang DM, et al. Elevated plasma level of visfatin/pre-B cell colony-enhancing factor in patients with type 2 diabetes mellitus. J Clin Endocrinol Metab, 2006,91(1):295-9
5 Graham TE, Yang Q, Bluher M, et al. Retinol-binding protein 4 and insulin resistance in lean, obese, and diabetic subjects. N Engl J Med, 2006,354(24):2552-63
6 Balagopal P, Graham TE, Kahn BB, et al. Reduction of elevated serum retinol binding protein in obese children by lifestyle intervention: association with subclinical inflammation. J Clin Endocrinol Metab, 2007,92(5):1971-4
7 Jimenez-Gomez Y, Lopez-Miranda J, Blanco-Colio LM, et al. Olive oil and walnut breakfasts reduce the postprandial inflammatory response in mononuclear cells compared with a butter breakfast in healthy men. Atherosclerosis, 2008, Epub ahead of print
8 Paniagua JA, Gallego de la Sacristana A, Romero I, et al. Monounsaturated fat-rich diet prevents central body fat distribution and decreases postprandial adiponectin expression induced by a carbohydrate-rich diet in insulin-resistant subjects. Diabetes Care, 2007,30(7):1717-23
9 Desroches S, Archer WR, Paradis ME, et al. Baseline plasma C-reactive protein concentrations influence lipid and lipoprotein responses to low-fat and high monounsaturated fatty acid diets in healthy men. J Nutr, 2006,136(4):1005-11
10 Flachs P, Mohamed-Ali V, Horakova O, et al. Polyunsaturated fatty acids of marine origin induce adiponectin in mice fed a high-fat diet. Diabetologia, 2006,49(2):394-7
11 Lithander FE, Keogh GF, Wang Y, et al. No evidence of an effect of alterations in dietary fatty acids on fasting adiponectin over 3 weeks. Obesity (Silver Spring), 2008,16(3):592-9
12 Freeman DJ, Norrie J, Sattar N, et al. Pravastatin and the development of diabetes mellitus: evidence for a protective treatment effect in the West of Scotland Coronary Prevention Study. Circulation, 2001,103(3):357-62
13 Yamauchi T, Kamon J, Waki H, et al. The fat-derived hormone adiponectin reverses insulin resistance associated with both lipoatrophy and obesity. Nat Med, 2001,7(8):941-6
14 Sun G, Bishop J, Khalili S, et al. Serum visfatin concentrations are positively correlated with serum triacylglycerols and down-regulated by overfeeding in healthy young men. Am J Clin Nutr, 2007,85(2):399-404
15 de Luis DA, Gonzalez Sagrado M, Conde R, et al. Effect of a hypocaloric diet on serum visfatin in obese non-diabetic patients. Nutrition, 2008,24(6):517-21
16周笑漪,徐焱成.高脂饮食诱导的胰岛素抵抗大鼠内脂素的表达水平.武汉大学学报(医学版),2007,28(3):324-8
17 Blaner WS. Retinol-binding protein: the serum transport protein for vitamin A. Endocr Rev, 1989,10(3):308-16
18吴海娅,魏丽,王琛.高脂或高糖饮食诱导胰岛素抵抗大鼠的附睾脂肪组织视黄醇结合蛋白4表达.上海医学, 2007, 30(6):446-9
19 Zacho J, Tybjaerg-Hansen A, Jensen JS, et al. Genetically elevated C-reactive protein and ischemic vascular disease. N Engl J Med, 2008,359(18):1897-908
1 Pahl HL. Signal transduction from the endoplasmic reticulum to the cell nucleus. Physiol Rev, 1999,79(3):683-701
2 Kaneto H, Nakatani Y, Kawamori D, et al. Role of oxidative stress, endoplasmic reticulum stress, and c-Jun N-terminal kinase in pancreatic beta-cell dysfunction and insulin resistance. Int J Biochem Cell Biol,2006,38(5-6):782-93
3 Xu C, Bailly-Maitre B, Reed JC. Endoplasmic reticulum stress: cell life and death decisions. J Clin Invest, 2005,115(10):2656-64
4 DuRose JB, Tam AB, Niwa M. Intrinsic capacities of molecular sensors of the unfolded protein response to sense alternate forms of endoplasmic reticulum stress. Mol Biol Cell, 2006,17(7):3095-107
5 Kraegen EW, James DE, Bennett SP, et al. In vivo insulin sensitivity in the rat determined by euglycemic clamp. Am J Physiol, 1983,245(1): E1-7
6 Soslow RA, Dannenberg AJ, Rush D, et al. COX-2 is expressed in human pulmonary, colonic, and mammary tumors. Cancer, 2000,89(12):2637-45
7 DeFronzo RA, Tobin JD, Andres R. Glucose clamp technique: a method for quantifying insulin secretion and resistance. Am J Physiol, 1979,237(3):E214-23
8 Scheen AJ, Lefebvre PJ. Assessment of insulin resistance in vivo: application to the study of type 2 diabetes. Horm Res, 1992,38(1-2): 19-27
9 Scheen AJ, Paquot N, Castillo MJ, et al. How to measure insulin action in vivo. Diabetes Metab Rev, 1994,10(2):151-88
10李伶,杨刚毅,方超,等.高脂喂养和脂质诱导的胰岛素抵抗大鼠糖代谢,抵抗素和脂联素的变化.中国糖尿病杂志, 2007,15(3):142-145
11罗四川,李启富,刘红梅.清醒状态大鼠高胰岛素-正常血糖钳夹术的建立及其意义.重庆医科大学学报, 2004,29(3):334-336
12 Ozcan U, Cao Q, Yilmaz E, et al. Endoplasmic reticulum stress links obesity, insulin action, and type 2 diabetes. Science, 2004,306(5695): 457-61
13 Harding HP, Zhang Y, Ron D. Protein translation and folding are coupled by an endoplasmic-reticulum-resident kinase. Nature, 1999,397(6716): 271-4
14 Wong WL, Brostrom MA, Kuznetsov G, et al. Inhibition of proteinsynthesis and early protein processing by thapsigargin in cultured cells. Biochem J, 1993,289 ( Pt 1):71-9
15 Kaufman RJ, Scheuner D, Schroder M, et al. The unfolded protein response in nutrient sensing and differentiation. Nat Rev Mol Cell Biol, 2002,3(6):411-21
16 Diakogiannaki E, Welters HJ, Morgan NG. Differential regulation of the endoplasmic reticulum stress response in pancreatic beta-cells exposed to long-chain saturated and monounsaturated fatty acids. J Endocrinol, 2008,197(3):553-63
17 Pachikian BD, Neyrinck AM, Cani PD, et al. Hepatic steatosis in n-3 fatty acid depleted mice: focus on metabolic alterations related to tissue fatty acid composition. BMC Physiol, 2008,8:21
18 Coll T, Eyre E, Rodriguez-Calvo R, et al. Oleate reverses palmitate-induced insulin resistance and inflammation in skeletal muscle cells. J Biol Chem, 2008,283(17):11107-16
19 Novoa I, Zhang Y, Zeng H, et al. Stress-induced gene expression requires programmed recovery from translational repression. EMBO J, 2003,22(5):1180-7
20 Kaufman RJ. Stress signaling from the lumen of the endoplasmic reticulum: coordination of gene transcriptional and translational controls. Genes Dev, 1999,13(10):1211-33
21 Wei Y, Wang D, Pagliassotti MJ. Saturated fatty acid-mediated endoplasmic reticulum stress and apoptosis are augmented by trans-10, cis-12-conjugated linoleic acid in liver cells. Mol Cell Biochem, 2007,303(1-2):105-13
1 Fukuhara A, Matsuda M, Nishizawa M, et al. Visfatin: a protein secreted by visceral fat that mimics the effects of insulin[J]. Science, 2005,307(5708):426-30
2 Ando H, Yanagihara H, Hayashi Y, et al. Rhythmic messenger ribonucleic acid expression of clock genes and adipocytokines in mouse visceral adipose tissue[J]. Endocrinology, 2005,146(12):5631-6
3 Choi KC, Ryu OH, Lee KW, et al. Effect of PPAR-alpha and -gamma agonist on the expression of visfatin, adiponectin, and TNF-alpha in visceral fat of OLETF rats[J]. Biochem Biophys Res Commun, 2005,336(3):747-53
4 Varma V, Yao-Borengasser A, Rasouli N, et al. Human visfatin expression: relationship to insulin sensitivity, intramyocellular lipids, and inflammation[J]. J Clin Endocrinol Metab, 2007,92(2):666-72
5 Moschen AR, Kaser A, Enrich B, et al. Visfatin, an adipocytokine with proinflammatory and immunomodulating properties[J]. J Immunol, 2007,178(3):1748-58
6 Ye, S. Q. et al. Pre-B-cell colony-enhancing factor as a potential novel biomarker in acute lung injury. Am. J. Respir. Crit. Care Med. 2005, 171(4):361-370
7 Jia, S. H. et al. Pre-B cell colony-enhancing factor inhibits neutrophil apoptosis in experimental inflammation and clinical sepsis[J]. J. Clin. Invest, 2004,113(9):1318-1327
8 Otero M, Lago R, Gomez R, et al. Changes in plasma levels of fat-derived hormones adiponectin, leptin, resistin and visfatin in patients with rheumatoid arthritis[J]. Ann Rheum Dis, 2006,65(9):1198-201
9 Zhang YY, Gottardo L, Thompson R, et al. A visfatin promoter polymorphism is associated with low-grade inflammation and type 2 diabetes[J]. Obesity (Silver Spring), 2006,14(12):2119-26
10 Sandeep S, Velmurugan K, Deepa R, et al. Serum visfatin in relation to visceral fat, obesity, and type 2 diabetes mellitus in Asian Indians[J]. Metabolism, 2007,56(4):565-70
11 Haider DG, Holzer G, Schaller G, et al. The adipokine visfatin is markedly elevated in obese children[J]. J Pediatr Gastroenterol Nutr, 2006,43(4):548-9
12 Haider DG, Schindler K, Schaller G, et al. Increased plasma visfatin concentrations in morbidly obese subjects are reduced after gastric banding[J]. J Clin Endocrinol Metab, 2006,91(4):1578-81
13 Manco M, Fernandez-Real JM, Equitani F, et al. Effect of massive weight loss on inflammatory adipocytokines and the innate immune system in morbidly obese women[J]. J Clin Endocrinol Metab, 2007, 92(2):483-90
14 Pagano C, Pilon C, Olivieri M, et al. Reduced plasma visfatin/pre-B cell colony-enhancing factor in obesity is not related to insulin resistance in humans[J]. J Clin Endocrinol Metab, 2006,91(8):3165-70
15 Jian WX, Luo TH, Gu YY, et al. The visfatin gene is associated with glucose and lipid metabolism in a Chinese population[J]. Diabet Med, 2006,23(9):967-73
16 Li L, Yang G, Li Q, et al. Changes and relations of circulating visfatin, apelin, and resistin levels in normal, impaired glucose tolerance, and type 2 diabetic subjects[J]. Exp Clin Endocrinol Diabetes, 2006, 114 (10):544-8
17 Chen MP, Chung FM, Chang DM, et al. Elevated plasma level of visfatin/pre-B cell colony-enhancing factor in patients with type 2 diabetes mellitus[J]. J Clin Endocrinol Metab, 2006,91(1):295-9
1 Jackson S, Bagstaff SM, Lynn S, et al. Decreased insulin responsiveness of glucose uptake in cultured human skeletal muscle cells from insulin-resistant nondiabetic relatives of type 2 diabetic families[J]. Diabetes, 2000,49(7):1169-77
2 Pratipanawatr W, Pratipanawatr T, Cusi K, et al. Skeletal muscle insulinresistance in normoglycemic subjects with a strong family history of type
2 diabetes is associated with decreased insulin-stimulated insulin receptor substrate-1 tyrosine phosphorylation[J]. Diabetes, 2001,50(11):2572-8
3 Storgaard H, Song XM, Jensen CB, et al. Insulin signal transduction in skeletal muscle from glucose-intolerant relatives of type 2 diabetic patients [corrected][J]. Diabetes, 2001,50(12):2770-8
4 Morino K, Petersen KF, Dufour S, et al. Reduced mitochondrial density and increased IRS-1 serine phosphorylation in muscle of insulin-resistant offspring of type 2 diabetic parents[J]. J Clin Invest, 2005, 115 (12):3587-93
5 Johanson EH, Jansson PA, Lonn L, et al. Fat distribution, lipid accumulation in the liver, and exercise capacity do not explain the insulin resistance in healthy males with a family history for type 2 diabetes[J]. J Clin Endocrinol Metab, 2003,88(9):4232-8
6 Petersen KF, Dufour S, Shulman GI. Decreased insulin-stimulated ATP synthesis and phosphate transport in muscle of insulin-resistant offspring of type 2 diabetic parents[J]. PLoS Med, 2005,2(9):e233
7 Karlsson HK, Ahlsen M, Zierath JR, et al. Insulin signaling and glucose transport in skeletal muscle from first-degree relatives of type 2 diabetic patients[J]. Diabetes, 2006,55(5):1283-8
8 Lattuada G, Costantino F, Caumo A, et al. Reduced whole-body lipid oxidation is associated with insulin resistance, but not with intramyocellular lipid content in offspring of type 2 diabetic patients[J]. Diabetologia, 2005,48(4):741-7
9 Mootha VK, Lindgren CM, Eriksson KF, et al. PGC-1alpha-responsive genes involved in oxidative phosphorylation are coordinately downregulated in human diabetes[J]. Nat Genet, 2003,34(3):267-73
10 Patti ME, Butte AJ, Crunkhorn S, et al. Coordinated reduction of genes of oxidative metabolism in humans with insulin resistance and diabetes: Potential role of PGC1 and NRF1[J]. Proc Natl Acad Sci U S A, 2003,100(14):8466-71
11 Befroy DE, Petersen KF, Dufour S, et al. Impaired mitochondrial substrate oxidation in muscle of insulin-resistant offspring of type 2 diabetic patients[J]. Diabetes, 2007,56(5):1376-81
12 Patil C, Walter P. Intracellular signaling from the endoplasmic reticulum to the nucleus: the unfolded protein response in yeast and mammals[J]. Curr Opin Cell Biol, 2001,13(3):349-55
13 DeGracia DJ, Kumar R, Owen CR, et al. Molecular pathways of protein synthesis inhibition during brain reperfusion: implications for neuronal survival or death[J]. J Cereb Blood Flow Metab, 2002,22(2):127-41
14 Tirasophon W, Welihinda AA, Kaufman RJ. A stress response pathway from the endoplasmic reticulum to the nucleus requires a novel bifunctional protein kinase/endoribonuclease (Ire1p) in mammalian cells[J]. Genes Dev, 1998,12(12):1812-24
15 Calfon M, Zeng H, Urano F, et al. IRE1 couples endoplasmic reticulum load to secretory capacity by processing the XBP-1 mRNA[J]. Nature, 2002,415(6867):92-6
16 Hollien J, Weissman JS. Decay of endoplasmic reticulum-localized mRNAs during the unfolded protein response[J]. Science, 2006,313(5783):104-7
17 Pirot P, Ortis F, Cnop M, et al. Transcriptional regulation of the endoplasmic reticulum stress gene chop in pancreatic insulin-producing cells[J]. Diabetes, 2007,56(4):1069-77
18 Kaneto H, Nakatani Y, Kawamori D, et al. Role of oxidative stress, endoplasmic reticulum stress, and c-Jun N-terminal kinase in pancreatic beta-cell dysfunction and insulin resistance[J]. Int J Biochem Cell Biol, 2006,38(5-6):782-93
19 Ozcan U, Cao Q, Yilmaz E, et al. Endoplasmic reticulum stress links obesity, insulin action, and type 2 diabetes[J]. Science, 2004, 306 (5695):457-61
20 Xu C, Bailly-Maitre B, Reed JC. Endoplasmic reticulum stress: cell life and death decisions[J]. J Clin Invest, 2005,115(10):2656-64
21 DuRose JB, Tam AB, Niwa M. Intrinsic capacities of molecular sensors of the unfolded protein response to sense alternate forms of endoplasmic reticulum stress[J]. Mol Biol Cell, 2006,17(7):3095-107
22 Nakatani Y, Kaneto H, Kawamori D, et al. Involvement of endoplasmic reticulum stress in insulin resistance and diabetes[J]. J Biol Chem, 2005,280(1):847-51
2 Parker DR, Weiss ST, Troisi R, et al. Relationship of dietary saturated fatty acids and body habitus to serum insulin concentrations: the Normative Aging Study. Am J Clin Nutr, 1993, 58(2): 129-36
3 Vessby B, Unsitupa M, Hermansen K, et al. Substituting dietary saturated for monounsaturated fat impairs insulin sensitivity in healthy men and women: The KANWU Study. Diabetologia, 2001, 44(3): 312-9
4 Meyer KA, Kushi LH, Jacobs DR Jr, et al. Dietary fat and incidence of type 2 diabetes in older Iowa women. Diabetes Care, 2001, 24(9):1528-35
5 Flachs P, Mohamed-Ali V, Horakova O, et al. Polyunsaturated fatty acids of marine origin induce adiponectin in mice fed a high-fat diet. Diabetologia, 2006, 49(2): 394-7
6 Sailaja JB, Balasubramaniyan V, Nalini N. Effect of exogenous leptin administration on high fat diet induced oxidative stress. Pharmazie, 2004,59(6): 475-9
7 Ozcan U, Yilmaz E, Ozcan L, et al. Chemical chaperones reduce ER stress and restore glucose homeostasis in a mouse model of type 2 diabetes. Science, 2006, 313(5790): 1137-40
8 Gorlach A, Klappa P, Kietzmann T. The endoplasmic reticulum: folding, calcium homeostasis, signaling, and redox control. Antioxid Redox Signal, 2006,8(9-10):1391-418
9 Chakravarthi S, Jessop CE, Bulleid NJ. The role of glutathione in disulphide bond formation and endoplasmic-reticulum-generated oxidative stress. EMBO Rep, 2006, 7(3):271-5
10 Fedoroff N. Redox regulatory mechanisms in cellular stress responses. Ann Bot (Lond), 2006,98(2):289-300
11 Karaskov E, Scott C, Zhang L, et al. Chronic palmitate but not oleate exposure induces endoplasmic reticulum stress, which may contribute to INS-1 pancreatic beta-cell apoptosis. Endocrinology, 2006, 147(7): 3398-407
1 Manco M, Calvani M, Mingrone G. Effects of dietary fatty acids oninsulin sensitivity and secretion. Diabetes Obes Metab, 2004,6(6):402-13
2 van Dam RM, Willett WC, Rimm EB, et al. Dietary fat and meat intake in relation to risk of type 2 diabetes in men. Diabetes Care, 2002,25(3):417-24
3 Meyer KA, Kushi LH, Jacobs DR Jr, et al. Dietary fat and incidence of type 2 diabetes in older Iowa women. Diabetes Care, 2001,24(9):1528-35
4 Thanopoulou AC, Karamanos BG, Angelico FV, et al. Dietary fat intake as risk factor for the development of diabetes: multinational, multicenter study of the Mediterranean Group for the Study of Diabetes (MGSD). Diabetes Care, 2003,26(2):302-7
5 Vessby B, Unsitupa M, Hermansen K, et al. Substituting dietary saturated for monounsaturated fat impairs insulin sensitivity in healthy men and women: The KANWU Study. Diabetologia, 2001,44(3):312-9
6 Fung TT, Rexrode KM, Mantzoros CS, et al. Mediterranean diet and incidence of and mortality from coronary heart disease and stroke in women. Circulation, 2009,119(8):1093-100
7 Martinez-Gonzalez MA, de la Fuente-Arrillaga C, Nunez-Cordoba JM, et al. Adherence to Mediterranean diet and risk of developing diabetes: prospective cohort study. BMJ, 2008,336(7657):1348-51
8 DeFronzo RA, Tobin JD, Andres R. Glucose clamp technique: a method for quantifying insulin secretion and resistance. Am J Physiol, 1979,237(3):E214-23
9 Pacini G, Bergman RN. MINMOD: a computer program to calculate insulin sensitivity and pancreatic responsivity from the frequently sampled intravenous glucose tolerance test. Comput Methods Programs Biomed, 1986,23(2):113-22
10 Matsuda M, DeFronzo RA. Insulin sensitivity indices obtained from oral glucose tolerance testing: comparison with the euglycemic insulin clamp. Diabetes Care, 1999,22(9):1462-70
11 Coll T, Eyre E, Rodriguez-Calvo R, et al. Oleate reverses palmitate-induced insulin resistance and inflammation in skeletal musclecells. J Biol Chem, 2008,283(17):11107-16
12 Davis JE, Gabler NK, Walker-Daniels J, et al. The c-Jun N-Terminal Kinase Mediates the Induction of Oxidative Stress and Insulin Resistance by Palmitate and Toll-like Receptor 2 and 4 Ligands in 3T3-L1 Adipocytes. Horm Metab Res, 2009
13 Perez-Jimenez F, Lopez-Miranda J, Pinillos MD, et al. A Mediterranean and a high-carbohydrate diet improve glucose metabolism in healthy young persons. Diabetologia, 2001,44(11):2038-43
14 Bayindir O, Ozmen D, Mutaf I, et al. Comparison of the effects of dietary saturated, mono-, and n-6 polyunsaturated fatty acids on blood lipid profile, oxidant stress, prostanoid synthesis and aortic histology in rabbits. Ann Nutr Metab, 2002,46(5):222-8
15 Lee JY, Sohn KH, Rhee SH, et al. Saturated fatty acids, but not unsaturated fatty acids, induce the expression of cyclooxygenase-2 mediated through Toll-like receptor 4. J Biol Chem, 2001, 276(20): 16683-9
16宋光耀,高宇,周宇.高饱和脂肪酸、高不饱和脂肪酸、高糖不同饮食诱导高血压伴胰岛素抵抗大鼠的研究.中国病理生理杂志, 2006, 22(11):2270-2273
1 Song F, Jia W, Yao Y, et al. Oxidative stress, antioxidant status and DNA damage in patients with impaired glucose regulation and newlydiagnosed Type 2 diabetes. Clin Sci (Lond), 2007,112(12):599-606
2 Allard JP, Aghdassi E, Mohammed S, et al. Nutritional assessment and hepatic fatty acid composition in non-alcoholic fatty liver disease (NAFLD): a cross-sectional study. J Hepatol, 2008,48(2):300-7
3 Haber CA, Lam TK, Yu Z, et al. N-acetylcysteine and taurine prevent hyperglycemia-induced insulin resistance in vivo: possible role of oxidative stress. Am J Physiol Endocrinol Metab, 2003,285(4):E744-53
4 Henriksen EJ. Exercise training and the antioxidant alpha-lipoic acid in the treatment of insulin resistance and type 2 diabetes. Free Radic Biol Med, 2006,40(1):3-12
5 Morrow JD. Quantification of isoprostanes as indices of oxidant stress and the risk of atherosclerosis in humans. Arterioscler Thromb Vasc Biol, 2005,25(2):279-86
6 Machado MV, Ravasco P, Jesus L, et al. Blood oxidative stress markers in non-alcoholic steatohepatitis and how it correlates with diet. Scand J Gastroenterol, 2008,43(1):95-102
7 Davis JE, Gabler NK, Walker-Daniels J, et al. The c-Jun N-Terminal Kinase Mediates the Induction of Oxidative Stress and Insulin Resistance by Palmitate and Toll-like Receptor 2 and 4 Ligands in 3T3-L1 Adipocytes. Horm Metab Res, 2009, Epub ahead of print
8 Colette C, Percheron C, Pares-Herbute N, et al. Exchanging carbohydrates for monounsaturated fats in energy-restricted diets: effects on metabolic profile and other cardiovascular risk factors. Int J Obes Relat Metab Disord, 2003,27(6):648-56
9 Pinotti MF, Silva MD, Sugizaki MM, et al. Influences of rich in saturated and unsaturated fatty acids diets in rat myocardium. Arq Bras Cardiol, 2007,88(3):346-53
10 Song BJ, Moon KH, Olsson NU, et al. Prevention of alcoholic fatty liver and mitochondrial dysfunction in the rat by long-chain polyunsaturated fatty acids. J Hepatol, 2008,49(2):262-73
11 Yuan M, Konstantopoulos N, Lee J, et al. Reversal of obesity- anddiet-induced insulin resistance with salicylates or targeted disruption of Ikkbeta. Science, 2001,293(5535):1673-7
12 Leslie NR. The redox regulation of PI 3-kinase-dependent signaling. Antioxid Redox Signal, 2006,8(9-10):1765-74
1 Fukuhara A, Matsuda M, Nishizawa M, et al. Visfatin: a protein secreted by visceral fat that mimics the effects of insulin. Science, 2005,307(5708):426-30
2 Yang Q, Graham TE, Mody N, et al. Serum retinol binding protein 4 contributes to insulin resistance in obesity and type 2 diabetes. Nature, 2005,436(7049):356-62
3 Li L, Yang G, Li Q, et al. Changes and relations of circulating visfatin,apelin, and resistin levels in normal, impaired glucose tolerance, and type
2 diabetic subjects. Exp Clin Endocrinol Diabetes, 2006,114(10):544-8
4 Chen MP, Chung FM, Chang DM, et al. Elevated plasma level of visfatin/pre-B cell colony-enhancing factor in patients with type 2 diabetes mellitus. J Clin Endocrinol Metab, 2006,91(1):295-9
5 Graham TE, Yang Q, Bluher M, et al. Retinol-binding protein 4 and insulin resistance in lean, obese, and diabetic subjects. N Engl J Med, 2006,354(24):2552-63
6 Balagopal P, Graham TE, Kahn BB, et al. Reduction of elevated serum retinol binding protein in obese children by lifestyle intervention: association with subclinical inflammation. J Clin Endocrinol Metab, 2007,92(5):1971-4
7 Jimenez-Gomez Y, Lopez-Miranda J, Blanco-Colio LM, et al. Olive oil and walnut breakfasts reduce the postprandial inflammatory response in mononuclear cells compared with a butter breakfast in healthy men. Atherosclerosis, 2008, Epub ahead of print
8 Paniagua JA, Gallego de la Sacristana A, Romero I, et al. Monounsaturated fat-rich diet prevents central body fat distribution and decreases postprandial adiponectin expression induced by a carbohydrate-rich diet in insulin-resistant subjects. Diabetes Care, 2007,30(7):1717-23
9 Desroches S, Archer WR, Paradis ME, et al. Baseline plasma C-reactive protein concentrations influence lipid and lipoprotein responses to low-fat and high monounsaturated fatty acid diets in healthy men. J Nutr, 2006,136(4):1005-11
10 Flachs P, Mohamed-Ali V, Horakova O, et al. Polyunsaturated fatty acids of marine origin induce adiponectin in mice fed a high-fat diet. Diabetologia, 2006,49(2):394-7
11 Lithander FE, Keogh GF, Wang Y, et al. No evidence of an effect of alterations in dietary fatty acids on fasting adiponectin over 3 weeks. Obesity (Silver Spring), 2008,16(3):592-9
12 Freeman DJ, Norrie J, Sattar N, et al. Pravastatin and the development of diabetes mellitus: evidence for a protective treatment effect in the West of Scotland Coronary Prevention Study. Circulation, 2001,103(3):357-62
13 Yamauchi T, Kamon J, Waki H, et al. The fat-derived hormone adiponectin reverses insulin resistance associated with both lipoatrophy and obesity. Nat Med, 2001,7(8):941-6
14 Sun G, Bishop J, Khalili S, et al. Serum visfatin concentrations are positively correlated with serum triacylglycerols and down-regulated by overfeeding in healthy young men. Am J Clin Nutr, 2007,85(2):399-404
15 de Luis DA, Gonzalez Sagrado M, Conde R, et al. Effect of a hypocaloric diet on serum visfatin in obese non-diabetic patients. Nutrition, 2008,24(6):517-21
16周笑漪,徐焱成.高脂饮食诱导的胰岛素抵抗大鼠内脂素的表达水平.武汉大学学报(医学版),2007,28(3):324-8
17 Blaner WS. Retinol-binding protein: the serum transport protein for vitamin A. Endocr Rev, 1989,10(3):308-16
18吴海娅,魏丽,王琛.高脂或高糖饮食诱导胰岛素抵抗大鼠的附睾脂肪组织视黄醇结合蛋白4表达.上海医学, 2007, 30(6):446-9
19 Zacho J, Tybjaerg-Hansen A, Jensen JS, et al. Genetically elevated C-reactive protein and ischemic vascular disease. N Engl J Med, 2008,359(18):1897-908
1 Pahl HL. Signal transduction from the endoplasmic reticulum to the cell nucleus. Physiol Rev, 1999,79(3):683-701
2 Kaneto H, Nakatani Y, Kawamori D, et al. Role of oxidative stress, endoplasmic reticulum stress, and c-Jun N-terminal kinase in pancreatic beta-cell dysfunction and insulin resistance. Int J Biochem Cell Biol,2006,38(5-6):782-93
3 Xu C, Bailly-Maitre B, Reed JC. Endoplasmic reticulum stress: cell life and death decisions. J Clin Invest, 2005,115(10):2656-64
4 DuRose JB, Tam AB, Niwa M. Intrinsic capacities of molecular sensors of the unfolded protein response to sense alternate forms of endoplasmic reticulum stress. Mol Biol Cell, 2006,17(7):3095-107
5 Kraegen EW, James DE, Bennett SP, et al. In vivo insulin sensitivity in the rat determined by euglycemic clamp. Am J Physiol, 1983,245(1): E1-7
6 Soslow RA, Dannenberg AJ, Rush D, et al. COX-2 is expressed in human pulmonary, colonic, and mammary tumors. Cancer, 2000,89(12):2637-45
7 DeFronzo RA, Tobin JD, Andres R. Glucose clamp technique: a method for quantifying insulin secretion and resistance. Am J Physiol, 1979,237(3):E214-23
8 Scheen AJ, Lefebvre PJ. Assessment of insulin resistance in vivo: application to the study of type 2 diabetes. Horm Res, 1992,38(1-2): 19-27
9 Scheen AJ, Paquot N, Castillo MJ, et al. How to measure insulin action in vivo. Diabetes Metab Rev, 1994,10(2):151-88
10李伶,杨刚毅,方超,等.高脂喂养和脂质诱导的胰岛素抵抗大鼠糖代谢,抵抗素和脂联素的变化.中国糖尿病杂志, 2007,15(3):142-145
11罗四川,李启富,刘红梅.清醒状态大鼠高胰岛素-正常血糖钳夹术的建立及其意义.重庆医科大学学报, 2004,29(3):334-336
12 Ozcan U, Cao Q, Yilmaz E, et al. Endoplasmic reticulum stress links obesity, insulin action, and type 2 diabetes. Science, 2004,306(5695): 457-61
13 Harding HP, Zhang Y, Ron D. Protein translation and folding are coupled by an endoplasmic-reticulum-resident kinase. Nature, 1999,397(6716): 271-4
14 Wong WL, Brostrom MA, Kuznetsov G, et al. Inhibition of proteinsynthesis and early protein processing by thapsigargin in cultured cells. Biochem J, 1993,289 ( Pt 1):71-9
15 Kaufman RJ, Scheuner D, Schroder M, et al. The unfolded protein response in nutrient sensing and differentiation. Nat Rev Mol Cell Biol, 2002,3(6):411-21
16 Diakogiannaki E, Welters HJ, Morgan NG. Differential regulation of the endoplasmic reticulum stress response in pancreatic beta-cells exposed to long-chain saturated and monounsaturated fatty acids. J Endocrinol, 2008,197(3):553-63
17 Pachikian BD, Neyrinck AM, Cani PD, et al. Hepatic steatosis in n-3 fatty acid depleted mice: focus on metabolic alterations related to tissue fatty acid composition. BMC Physiol, 2008,8:21
18 Coll T, Eyre E, Rodriguez-Calvo R, et al. Oleate reverses palmitate-induced insulin resistance and inflammation in skeletal muscle cells. J Biol Chem, 2008,283(17):11107-16
19 Novoa I, Zhang Y, Zeng H, et al. Stress-induced gene expression requires programmed recovery from translational repression. EMBO J, 2003,22(5):1180-7
20 Kaufman RJ. Stress signaling from the lumen of the endoplasmic reticulum: coordination of gene transcriptional and translational controls. Genes Dev, 1999,13(10):1211-33
21 Wei Y, Wang D, Pagliassotti MJ. Saturated fatty acid-mediated endoplasmic reticulum stress and apoptosis are augmented by trans-10, cis-12-conjugated linoleic acid in liver cells. Mol Cell Biochem, 2007,303(1-2):105-13
1 Fukuhara A, Matsuda M, Nishizawa M, et al. Visfatin: a protein secreted by visceral fat that mimics the effects of insulin[J]. Science, 2005,307(5708):426-30
2 Ando H, Yanagihara H, Hayashi Y, et al. Rhythmic messenger ribonucleic acid expression of clock genes and adipocytokines in mouse visceral adipose tissue[J]. Endocrinology, 2005,146(12):5631-6
3 Choi KC, Ryu OH, Lee KW, et al. Effect of PPAR-alpha and -gamma agonist on the expression of visfatin, adiponectin, and TNF-alpha in visceral fat of OLETF rats[J]. Biochem Biophys Res Commun, 2005,336(3):747-53
4 Varma V, Yao-Borengasser A, Rasouli N, et al. Human visfatin expression: relationship to insulin sensitivity, intramyocellular lipids, and inflammation[J]. J Clin Endocrinol Metab, 2007,92(2):666-72
5 Moschen AR, Kaser A, Enrich B, et al. Visfatin, an adipocytokine with proinflammatory and immunomodulating properties[J]. J Immunol, 2007,178(3):1748-58
6 Ye, S. Q. et al. Pre-B-cell colony-enhancing factor as a potential novel biomarker in acute lung injury. Am. J. Respir. Crit. Care Med. 2005, 171(4):361-370
7 Jia, S. H. et al. Pre-B cell colony-enhancing factor inhibits neutrophil apoptosis in experimental inflammation and clinical sepsis[J]. J. Clin. Invest, 2004,113(9):1318-1327
8 Otero M, Lago R, Gomez R, et al. Changes in plasma levels of fat-derived hormones adiponectin, leptin, resistin and visfatin in patients with rheumatoid arthritis[J]. Ann Rheum Dis, 2006,65(9):1198-201
9 Zhang YY, Gottardo L, Thompson R, et al. A visfatin promoter polymorphism is associated with low-grade inflammation and type 2 diabetes[J]. Obesity (Silver Spring), 2006,14(12):2119-26
10 Sandeep S, Velmurugan K, Deepa R, et al. Serum visfatin in relation to visceral fat, obesity, and type 2 diabetes mellitus in Asian Indians[J]. Metabolism, 2007,56(4):565-70
11 Haider DG, Holzer G, Schaller G, et al. The adipokine visfatin is markedly elevated in obese children[J]. J Pediatr Gastroenterol Nutr, 2006,43(4):548-9
12 Haider DG, Schindler K, Schaller G, et al. Increased plasma visfatin concentrations in morbidly obese subjects are reduced after gastric banding[J]. J Clin Endocrinol Metab, 2006,91(4):1578-81
13 Manco M, Fernandez-Real JM, Equitani F, et al. Effect of massive weight loss on inflammatory adipocytokines and the innate immune system in morbidly obese women[J]. J Clin Endocrinol Metab, 2007, 92(2):483-90
14 Pagano C, Pilon C, Olivieri M, et al. Reduced plasma visfatin/pre-B cell colony-enhancing factor in obesity is not related to insulin resistance in humans[J]. J Clin Endocrinol Metab, 2006,91(8):3165-70
15 Jian WX, Luo TH, Gu YY, et al. The visfatin gene is associated with glucose and lipid metabolism in a Chinese population[J]. Diabet Med, 2006,23(9):967-73
16 Li L, Yang G, Li Q, et al. Changes and relations of circulating visfatin, apelin, and resistin levels in normal, impaired glucose tolerance, and type 2 diabetic subjects[J]. Exp Clin Endocrinol Diabetes, 2006, 114 (10):544-8
17 Chen MP, Chung FM, Chang DM, et al. Elevated plasma level of visfatin/pre-B cell colony-enhancing factor in patients with type 2 diabetes mellitus[J]. J Clin Endocrinol Metab, 2006,91(1):295-9
1 Jackson S, Bagstaff SM, Lynn S, et al. Decreased insulin responsiveness of glucose uptake in cultured human skeletal muscle cells from insulin-resistant nondiabetic relatives of type 2 diabetic families[J]. Diabetes, 2000,49(7):1169-77
2 Pratipanawatr W, Pratipanawatr T, Cusi K, et al. Skeletal muscle insulinresistance in normoglycemic subjects with a strong family history of type
2 diabetes is associated with decreased insulin-stimulated insulin receptor substrate-1 tyrosine phosphorylation[J]. Diabetes, 2001,50(11):2572-8
3 Storgaard H, Song XM, Jensen CB, et al. Insulin signal transduction in skeletal muscle from glucose-intolerant relatives of type 2 diabetic patients [corrected][J]. Diabetes, 2001,50(12):2770-8
4 Morino K, Petersen KF, Dufour S, et al. Reduced mitochondrial density and increased IRS-1 serine phosphorylation in muscle of insulin-resistant offspring of type 2 diabetic parents[J]. J Clin Invest, 2005, 115 (12):3587-93
5 Johanson EH, Jansson PA, Lonn L, et al. Fat distribution, lipid accumulation in the liver, and exercise capacity do not explain the insulin resistance in healthy males with a family history for type 2 diabetes[J]. J Clin Endocrinol Metab, 2003,88(9):4232-8
6 Petersen KF, Dufour S, Shulman GI. Decreased insulin-stimulated ATP synthesis and phosphate transport in muscle of insulin-resistant offspring of type 2 diabetic parents[J]. PLoS Med, 2005,2(9):e233
7 Karlsson HK, Ahlsen M, Zierath JR, et al. Insulin signaling and glucose transport in skeletal muscle from first-degree relatives of type 2 diabetic patients[J]. Diabetes, 2006,55(5):1283-8
8 Lattuada G, Costantino F, Caumo A, et al. Reduced whole-body lipid oxidation is associated with insulin resistance, but not with intramyocellular lipid content in offspring of type 2 diabetic patients[J]. Diabetologia, 2005,48(4):741-7
9 Mootha VK, Lindgren CM, Eriksson KF, et al. PGC-1alpha-responsive genes involved in oxidative phosphorylation are coordinately downregulated in human diabetes[J]. Nat Genet, 2003,34(3):267-73
10 Patti ME, Butte AJ, Crunkhorn S, et al. Coordinated reduction of genes of oxidative metabolism in humans with insulin resistance and diabetes: Potential role of PGC1 and NRF1[J]. Proc Natl Acad Sci U S A, 2003,100(14):8466-71
11 Befroy DE, Petersen KF, Dufour S, et al. Impaired mitochondrial substrate oxidation in muscle of insulin-resistant offspring of type 2 diabetic patients[J]. Diabetes, 2007,56(5):1376-81
12 Patil C, Walter P. Intracellular signaling from the endoplasmic reticulum to the nucleus: the unfolded protein response in yeast and mammals[J]. Curr Opin Cell Biol, 2001,13(3):349-55
13 DeGracia DJ, Kumar R, Owen CR, et al. Molecular pathways of protein synthesis inhibition during brain reperfusion: implications for neuronal survival or death[J]. J Cereb Blood Flow Metab, 2002,22(2):127-41
14 Tirasophon W, Welihinda AA, Kaufman RJ. A stress response pathway from the endoplasmic reticulum to the nucleus requires a novel bifunctional protein kinase/endoribonuclease (Ire1p) in mammalian cells[J]. Genes Dev, 1998,12(12):1812-24
15 Calfon M, Zeng H, Urano F, et al. IRE1 couples endoplasmic reticulum load to secretory capacity by processing the XBP-1 mRNA[J]. Nature, 2002,415(6867):92-6
16 Hollien J, Weissman JS. Decay of endoplasmic reticulum-localized mRNAs during the unfolded protein response[J]. Science, 2006,313(5783):104-7
17 Pirot P, Ortis F, Cnop M, et al. Transcriptional regulation of the endoplasmic reticulum stress gene chop in pancreatic insulin-producing cells[J]. Diabetes, 2007,56(4):1069-77
18 Kaneto H, Nakatani Y, Kawamori D, et al. Role of oxidative stress, endoplasmic reticulum stress, and c-Jun N-terminal kinase in pancreatic beta-cell dysfunction and insulin resistance[J]. Int J Biochem Cell Biol, 2006,38(5-6):782-93
19 Ozcan U, Cao Q, Yilmaz E, et al. Endoplasmic reticulum stress links obesity, insulin action, and type 2 diabetes[J]. Science, 2004, 306 (5695):457-61
20 Xu C, Bailly-Maitre B, Reed JC. Endoplasmic reticulum stress: cell life and death decisions[J]. J Clin Invest, 2005,115(10):2656-64
21 DuRose JB, Tam AB, Niwa M. Intrinsic capacities of molecular sensors of the unfolded protein response to sense alternate forms of endoplasmic reticulum stress[J]. Mol Biol Cell, 2006,17(7):3095-107
22 Nakatani Y, Kaneto H, Kawamori D, et al. Involvement of endoplasmic reticulum stress in insulin resistance and diabetes[J]. J Biol Chem, 2005,280(1):847-51