新脂肪細(xì)胞因子視黃醇結(jié)合蛋白4與肥胖及脂代謝的關(guān)系及機制研究_圖文

1、上海交通大學(xué)博士學(xué)位論文新脂肪細(xì)胞因子視黃醇結(jié)合蛋白4與肥胖及脂代謝的關(guān)系及機制研究姓名：吳海婭申請學(xué)位級別：博士專業(yè)：內(nèi)分泌代謝學(xué)指導(dǎo)教師：賈偉平20070501上海交通大學(xué)醫(yī)學(xué)院2004級博士研究生學(xué)位論文主要符號和縮略語說明英文縮寫 英文全稱 中文譯名ALT alanine aminotransferase 谷丙轉(zhuǎn)氨酶APN adiponectin 脂聯(lián)素BMI bodymass index 體重指數(shù)FPGfasting plasma glucose 空腹血糖 FFAfree fatty acid 游離脂肪酸 FINSfasting insulin 空腹胰島素 GLUT4glucose

2、transporter 4 葡萄糖轉(zhuǎn)運子4 GT-glutamyltransferase 谷氨酰轉(zhuǎn)肽酶 HDL-C highdensity lipoprotein cholesterol 高密度脂蛋白膽固醇 HbA1c Glycated Hemoglobin A1c糖化血紅蛋白 NCnormal control 正常對照 NGTnormal glucose tolerance 正常糖耐量 NWnormal weight 正常體重 LDL-C lowdensity lipoprotein cholesterol 低密度脂蛋白膽固醇 PPAR peroxisomeproliferators act

3、ivated receptor 過氧化物酶體增殖子 激活受體 RBP4 retinolbinding protein 4 視黃醇結(jié)合蛋白4 RT-PCRreverse transcription PCR 反轉(zhuǎn)錄PCR SD ratSprague-Dawley rat SD 大鼠 TCtotle cholesterol 總膽固醇 T2DM type2 diabetes mellitus 2型糖尿病 TGtriglyceride 甘油三脂19上海交通大學(xué)學(xué)位論文版權(quán)使用授權(quán)書本學(xué)位論文作者完全了解學(xué)校有關(guān)保留、使用學(xué)位論文的規(guī)定，同意學(xué)校保留并向國家有關(guān)部門或機構(gòu)送交論文的復(fù)印件和電子版，允許論文

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5、擔(dān)。學(xué)位論文作者簽名：日期： 年 月 日6新脂肪細(xì)胞因子視黃醇結(jié)合蛋白4與肥胖及脂代謝的關(guān)系及機制研究摘 要第一部分 肥胖及2型糖尿病患者血清視黃醇結(jié)合蛋白4水平的臨床研究目的：Yang 等利用基因芯片比較了脂肪組織特異性過表達(dá)葡萄糖轉(zhuǎn)運子4（GluT4-Tg）和脂肪特異性剔除GluT4（ GluT4（-/-）小鼠附睪脂肪組織的基因表達(dá)譜，鑒定出一種新的參與胰島素抵抗發(fā)生的脂肪細(xì)胞因子視黃醇結(jié)合蛋白4 (RBP4。然而，RBP4是主要由肝臟合成和分泌，但血清RBP4與肝臟的關(guān)系仍具爭議。RBP4在人群中的研究資料尚少，它在人體內(nèi)的病理生理意義仍需進(jìn)一步的研究。本研究主要通過臨床研究探討：1.

6、血清RBP4在肥胖和2型糖尿病患者中的變化。2. 血清RBP4與體脂、糖、脂代謝及肝功能的關(guān)系。3. 血清RBP4與游離脂肪酸以及脂肪細(xì)胞因子，如脂聯(lián)素之間的關(guān)系。 對象與方法：我們?nèi)脒x131例上海地區(qū)中國人，年齡2069歲，分組：正常對照組（NC）（n=31）和正常糖耐量超重/肥胖者（OW/OB-NGT）（n=31）、2型糖尿病正常體重組（NW-T2DM）（n=33）和2型糖尿病伴超重/肥胖組（OW/OB-T2DM）（n=36）。采用HOMA-IR評價各組胰島素抵抗程度，測定受試者的體重指數(shù)（BMI）、腰臀比（WHR），體脂含量（Fat%）；檢測空腹?fàn)顟B(tài)下血糖（FPG）、糖化血紅蛋白（HbA

7、1c）、谷丙轉(zhuǎn)氨酶（ALT）、谷氨酰轉(zhuǎn)肽酶（GT）、膽固醇（TC）、甘油三酯（TG）、高密度脂蛋白膽固醇（HDL-C）、低密度脂蛋白膽固醇（LDL-C）、游離脂肪酸（FFA）、胰島素（FINS）、脂聯(lián)素（ADP）和RBP4。結(jié)果：71. 校正年齡后，男性的血清RBP4顯著高于女性 (30.00±0.78 vs . 27.27±0.80g/ml，P 0.05。校正年齡、性別后，OW/OB-NGT 及OW/OB-T2DM組的血清RBP4水平顯著高于NW-NGT組 (29.85±6.60，30.86±6.11 g/ml vs . 25.47±6.84

8、 g/ml，均P 0.05。2. NW-T2DM與NW-NGT組間的血清RBP4差異無顯著性(25.47±6.84 vs 28.35±5.42 g/ml，但顯著低于OW/OB-T2DM (30.86±6.11 vs . 28.35±5.42 g/ml， P 0.05。3. 單因素回歸分析見到，血清RBP4與BMI、Fat%、W、WHR、TG及HOMA-IR呈顯著正相關(guān)，未見到RBP4與ALT和GT有顯著相關(guān)。多元逐步回歸分析見到，WHR，TG和年齡是血清RBP4的獨立相關(guān)因素。4. 將131名研究對象再次分組：正常甘油三酯伴正常腰臀比組（NTG-NCO）

9、TG1.7mmol/L，WHR0.90（男性），WHR0.85（女性）（n=39），正常甘油三酯伴中心性肥胖組（NTG-NCO）（n=43），高甘油三酯伴正常腰臀比組（HTG-NCO）（n=11）和高甘油三酯伴中心性肥胖組（HTG-CO）（n=38）。校正年齡、性別后，HTG-NCO和HTG-CO兩組的血清RBP4水平均顯著高于NTG-NCO和NTG-CO組(28.89±0.87 vs. 26.20±0.97 g/ml；(31.59±0.97 vs . 27.39±1.58 g/ml，均P 0.01；HTG-CO的RBP4水平顯著高于HTG-NCO組(3

10、1.59±0.97 vs . 28.89±0.87 g/ml， P 0.01，但在NTG-CO與NTG-NCO兩組間的血清RBP4水平差異無顯著性(27.39±1.58 vs . 26.20±0.97 g/ml，P >0.05。小結(jié)：1. 肥胖者的血清RBP4顯著升高。2. 血清RBP4與WHR，TG，年齡呈正相關(guān)。3. RBP4與血糖、血壓、血脂以及中心型肥胖等與胰島素抵抗有關(guān)指標(biāo)有著不同程度的相關(guān)，表明RBP4是提示代謝綜合征的一項血清學(xué)標(biāo)志物。4. 肥胖者和糖尿病患者的ALT 和GT較高，其肝臟可能存在不同程度脂質(zhì)沉積，但我們未發(fā)現(xiàn)這組人群的

11、血清RBP4變化與ALT 和GT有顯著相關(guān)。8第二部分 視黃醇結(jié)合蛋白4在大鼠各組織中的表達(dá)目的：RBP4在肝臟、腎、脂肪和骨骼肌等多種組織均有合成。本研究通過動物試驗，闡明生理狀態(tài)下RBP4在機體各組織的表達(dá)水平，為研究生理及病理狀態(tài)下RBP4表達(dá)水平變化提供依據(jù)。材料與方法：應(yīng)用RT-PCR 和免疫組化的方法，對5只健康雄性SD 大鼠的主要器官（肝臟、脂肪、骨骼肌、腎臟和心肌組織）RBP4的表達(dá)進(jìn)行了測定及比較。結(jié)果：1. 根據(jù)PCR 產(chǎn)物測序結(jié)果，與Pudmed 上公布的各基因mRNA 標(biāo)準(zhǔn)序列進(jìn)行比較分析，證實PCR 產(chǎn)物確為我們所需要的目標(biāo)產(chǎn)物。2. RBP4在各組織表達(dá)強度分別為：

12、肝臟（3.52±0.39），腎臟（3.63±0.63），脂肪（0.64±0.11），肌肉（0.38±0.06）和心臟（0.24±0.10）。3. RBP4彌漫分布于肝細(xì)胞以及膽管內(nèi)；充滿腎小管管腔及其上皮組織；散在脂肪細(xì)胞周邊以及骨骼肌和心肌細(xì)胞內(nèi)。4. 健康雄性SD 大鼠脂肪組織中RBP4與GluT4mRNA 的表達(dá)水平呈負(fù)相關(guān)（相關(guān)系數(shù)r= -0.667，P=0.219），但未達(dá)統(tǒng)計學(xué)意義。小結(jié)：1. RBP4在肝臟、脂肪、骨骼肌、腎臟和心肌組織均有表達(dá)，以肝臟和腎臟表達(dá)最強，脂肪其次，肌肉和心臟最少。2. RBP4彌漫分布于肝細(xì)胞以及膽管

13、內(nèi)；充滿腎小管管腔及其上皮組織；散在脂肪細(xì)胞周邊以及骨骼肌和心肌細(xì)胞內(nèi)。3. 在健康雄性SD 大鼠脂肪組織中，未見到RBP4與GluT4的相關(guān)。9第三部分 非諾貝特對高脂、高糖喂養(yǎng)大鼠血清、肝臟及脂肪組織視黃醇結(jié)合蛋白4表達(dá)的影響目的：RBP4新功能的發(fā)現(xiàn)，為治療胰島素抵抗和糖尿病提供了新的靶點。貝特類藥物具有減重和改善胰島素敏感性的功能。動物實驗證明改善胰島素敏感性可降低體內(nèi) RPB4水平，故推測這類藥也可能有降低體內(nèi)RBP4水平的作用。本研究通過動物試驗探討：1. RBP4在高脂肥胖胰島素抵抗大鼠模型血清、肝臟和脂肪組織中的變化。2. 非諾貝特對高脂肥胖胰島素抵抗大鼠模型血清、肝臟和脂肪組

14、織中RBP4和GluT4水平的影響。材料與方法：40只雄性SD 大鼠隨機分為5組，普通飲食（NC）組、高脂飲食對照（FC）組和高糖飲食對照（SC）組，高脂飲食治療（FF）組和高糖飲食治療（SF）組，每組8只大鼠。喂養(yǎng)6周后，NC組予生理鹽水，F(xiàn)C和SC 組予牛奶，治療組予非諾貝特100mg/kg灌胃2周后，行口服糖耐量試驗和胰島素耐量試驗檢測胰島功能，取空腹血清檢測血脂和胰島素等，并取附睪、腎周脂肪和肝臟組織稱重，計算脂體比和飼養(yǎng)效率，RT-PCR檢測附睪脂肪和肝臟組織RBP4和GluT4 mRNA表達(dá)水平。結(jié)果：1. FC 和SC 組大鼠糖耐量和胰島素耐量受損，血脂紊亂，空腹血糖和胰島素升高

15、，脂體比增加，肝臟出現(xiàn)了脂質(zhì)沉積。FC和SC 組的大鼠血清RBP4水平顯著高于NC 組1.84和1.57倍，附睪脂肪組織RBP4mRNA 水平顯著高于NC組2.47倍和2.35倍，而GluT4顯著低于NC 組1.5倍和1.37倍，而三組肝臟RBP4mRNA 水平無顯著差異。2. 非諾貝特治療后，治療組體重、脂體比和飼養(yǎng)效率有所下降，血脂譜、胰島素敏感性和肝臟脂質(zhì)沉積較對照組均有所改善。FF 組血清RBP4和附睪脂肪組織RBP4mRNA 水平較FC 組分別下降了20.7和56.4；SF組較SC 組10分別下降了24和52，治療組附睪脂肪組織GluT4mRNA 水平較對照組均有升高，但各組肝臟RB

16、P4 mRNA水平無顯著差異。3. 單因素相關(guān)分析見到，血清RBP4與脂肪組織RBP4mRNA 水平顯著相關(guān)，且兩者均與體脂相關(guān)參數(shù)，糖脂代謝以及胰島素抵抗相關(guān)指標(biāo)呈顯著相關(guān)，而與脂肪組織GluT4mRNA 水平呈顯著負(fù)相關(guān)，肝臟組織RBP4mRNA 與各項代謝指標(biāo)以及脂肪組織GluT4mRNA 水平均無顯著相關(guān)。小結(jié)：1 成功地制作了高脂、高糖誘導(dǎo)胰島素抵抗大鼠模型。2 高脂或高糖的飲食結(jié)構(gòu)都可導(dǎo)致肥胖的發(fā)生，并刺激脂肪組織RBP4的表達(dá)增加。 RBP4與血糖，血脂代謝，腹內(nèi)脂肪重量以及胰島素抵抗密切相關(guān)，提示RBP4可能是一個代謝綜合征的生物學(xué)標(biāo)志物。3 非諾貝特可以改善血脂，增強胰島素敏

17、感性，減少脂肪RBP4的表達(dá)。4 胰島素抵抗?fàn)顟B(tài)下，脂肪細(xì)胞可能是血清RBP4主要來源。然而，由于我們未檢測肌肉，腎臟等組織RBP4的變化，故不能排除PPAR 激動劑對這些組織RBP4合成的影響以及其他組織對血清RBP4的貢獻(xiàn)。結(jié) 論1. RBP4與血糖、血脂、血壓以及中心型肥胖等與胰島素抵抗有關(guān)指標(biāo)有著不同程度的相關(guān)，提示RBP4可能是提示代謝綜合征的一項血清學(xué)標(biāo)志物。2. RBP4在大鼠肝臟和腎臟表達(dá)最強，脂肪次之，而骨骼肌和心肌RBP4的表達(dá)最少。3. 非諾貝特可以改善血脂，減少腹內(nèi)脂肪含量，增強胰島素敏感性，減少脂肪RBP4的表達(dá)。4. 在胰島素抵抗?fàn)顟B(tài)下，脂肪組織可能是血清RBP4主

18、要來源。然而，由于我們未檢測肌肉，腎臟等組織RBP4的變化，故不能排除PPAR 激動劑對這些組織RBP4合成的影響以及其他組織對血清RBP4的貢獻(xiàn)。關(guān)鍵詞 視黃醇結(jié)合蛋白4，葡萄糖轉(zhuǎn)運子4，胰島素抵抗，腹型肥胖，非諾貝特 11上海交通大學(xué)醫(yī)學(xué)院2004級博士研究生學(xué)位論文THE STUDY ON THE MECHANISM AND RELATIONSHIP OF THE NEW ADIPOCYTOKINE, RETINOL BINDING PROTEIN 4,OBESITY, AND LIPID METABOLISMABSTRACTPart 1 The clinical study on ob

19、esity, type 2 diabetes, and serum retinol binding protein 4Objective:Yang et al performed DNA array on epididymal adipose tissue RNA from the adipose specific overexpression of Glucose transporter 4 mice and GluT4 (-/- mice, and identified a new protein associated with insulin resistanceretinol bind

20、ing protein (RBP4. However, RBP4 was mainly expressed and secreted by liver, and the relationship of serum RBP4 and liver was still controversial. In short, the human study on RBP4 was limited and its pathophysiological roles in human should be further explored. By the clinical research, this study

21、illuminated that:1. The change of serum RBP4 in obesity and type 2 diabetes2. The relationships of serum RBP4, body fat, glucose and lipid metabolism, andliver function.3. The relationships of serum RBP4, free fat acid and adipocytokines, such asadiponectin.Subjects and methods:131 enrolled subjects

22、, aged from 20 to 69, were divided into 4 groups: normal control (NC (n=31, normal glucose tolerance with overweight or obesity (OW/OB-NGR (n=31, type 2 diabetes mellitus with normal weight (NW-T2DM (n=33, and type 2 12diabetes mellitus with overweight or obesity (OW/OB-T2DM (n=36. We evaluated the

23、extent of insulin resistance by use of HOMA-IR index, and measured body mass index (BMI, waist-to-hip ratio (WHR and body fat percent (Fat%. We assayed plasma glucose (FPG, Glycated Hemoglobin A1c (HbA1c, alanine aminotransferase (ALT, -glutamyltransferase (GT, total cholesterol (TC, triglycerides (

24、TG, high density lipoprotein-cholesterol (HDL-C, low density lipoprotein-cholesterol (LDL-C, free fat acid (FFA, insulin (FINS, RBP4 and adiponectin (APN in fasting state. Results:1. After adjustment of age, men had higher serum RBP4 level than women(30.00±0.78 vs 27.27±0.80 g/ml, P0.05. A

25、fter age and sex adjusted, serum RBP4 levels in OW/OB-NGR and OW/OB- T2DM were significantly elevated compared to the NC group (29.85±6.60，30.86±6.11 g/ml vs. 25.47±6.84 g/ml, both P 0.05.2. There is no significant difference between NC and NW-T2DM (25.47±6.84vs28.35±5.42 g/

26、ml. The serum RBP4 level in OW/OB-T2DM is significantly higher than that of NW-T2DM (30.86±6.11 vs. 28.35±5.42 g/ml, P0.05.3. Simple correlation analyses showed that serum RBP4 was correlated with BMI,Fat%, W, WHR, TG and HOMA-IR, and had no significant correlation with ALT and GT. Multipl

27、e linear regression analyses reveal that WHR, TG and age were independent variables for RBP4.4. Total of 131 subjects were re-divided into 4 groups: normal TG with normal WHR(NTG-NCO group TG1.7mmol/L, WHR0.90 in male, WHR0.85 in female (n=39, normal TG with central obesity (NTG-NCO group (n=43, hig

28、h TG with normal WHR (HTG-NCO group (n=11, and high TG with central obesity (HTG-CO group (n=38. After age, sex adjusted, serum RBP4 levels in the high TG group were significantly higher than that of the non- or central obesity groups with normal TG (28.89±0.87 vs. 26.20±0.97 g/ml; (31.59&

29、#177;0.97 vs. 27.39±1.58 g/ml, both P0.01; serum RBP4 levels in HTG-CO group was higher than that in HTG-NCO group (31.59±0.97 vs. 28.89±0.87 g/ml, P0.01. However, there was no significant difference in the RBP4 levels between the groups of NTG-CO and NTG-NCO(27.39±1.58 vs. 26.20

30、±0.97 g/ml, P>0.05.Part 1 conclusion:1. Serum RBP4 was elevated in obesity.2. Serum RBP4 was positively correlated with WHR, TG and age.3. It demonstrated that RBP4 was related with the parameters about insulin resistance,such as lipid profiles and central obesity, and implied that RBP4 coul

31、d be a serum marker for identifying metabolic syndrome.4. The obesity and T2DM patients in our study had higher ALT and GT, whichinferred that there would be lipid accumulating in their livers to some extent, whereas we did not find the facts that RBP4 was associated with ALT and GT in these groups.

32、Part 2 The expression levels of retinol binding protein 4 in various tissues of rats Objective:RBP4 was produced in many tissues, such as liver, kidney, adipose, muscle and so on. This study explored the RBP4 levels in various tissues in the physiological state to provide the evidence on the change

33、of RBP4 levels in the pathophysiological states via animal experiments.Materials and methodsWe evaluated the RBP4 levels in the main organs (liver, adipose, muscle, kidney and myocardial tissues of 5 healthy male SD rats by RT-PCR and immunohistology. Results:1. According to the results of sequencin

34、g PCR products, and comparison betweeneach mRNA standard sequences on Pubmed and PCR products, we confirmed that PCR products were the objective products that we wanted.2. The expression levels of RBP4 in various tissues were liver (3.52±0.39, kidney(3.63±0.63, adipose (0.64±0.11, mus

35、cle (0.38±0.06 and myocardial tissue (0.24±0.10.3. RBP4 was diffused in hepatocytes and billiary ducts; accumulated in tubular andepithelial tissue of kidney; scattered on the board of adipocytes and in muscle and myocardial cells.4. RBP4 was negatively correlated with GluT4mRNA in adipose

36、 tissues of healthymale SD rats, but it had no significance.Part 2 conclusion1. RBP4 was expressed in liver, adipose, muscle, kidney and myocardial tissues, and itwas higher in the liver and kidney, moderate in the adipose, and lower in muscle and myocardial tissues.2. RBP4 was diffused in hepatocyt

37、es and billiary ducts; accumulated in tubular andepithelial tissue of kidney; scattered on the board of adipocytes and in muscle and myocardial cells.3. We did not find the relationship between RBP4 and GluT4 in the adipose of healthymale SD rats.Part 3 The influence of fenofibrates on the expressio

38、n of RBP4 in serum, liver and adipose of rats fed on high fat or high sugar dietsObjective:The discovery of the new function of RBP4 provided the treatment target on insulin resistance and diabetes. Fibrates had effects of losing weight and increasing insulin sensitivity. Animal experiments showed i

39、mprovement of insulin sensitivity could lowerthe serum level of RBP4, so we hypothesized that fribrates also could have this effect. Via animal experiments, this study discussed:1. The change of RBP4 in serum, liver and adipose of rats with hyperlipidemia andinsulin resistance.2. The influence of fe

40、nofibrates on the expression of RBP4 and GluT4 in serum, liverand adipose of rats with hyperlipidemia and insulin resistance.Materials and methods:40 Male SD rats were randomly divided into 5 groups, normal diet (NC group, high fat diet control (FC group, high sugar diet control (SC group, high fat

41、diet treated by fenofibrate (FF group, and high sugar diet treated by fenofibrate (SF group, and each group included 8 rats. After 6 weeks fed by different diets, NC group was gavaged by normal saline, FC and SC groups were gavaged by milk, and the treatment groups were gavaged by fenofibrate, 100mg

42、/kg for 2 weeks. Then we performed oral glucose tolerance test and insulin tolerance test to assay islet function, and collected the fasting serum to measure lipid profiles and insulin and so on. We also weighed epididymal adipose, adipose around kidney and liver, and calculated fat to body weight r

43、atio and feeding efficiency. We employed the method of RT-PCR to relatively quantify RBP4 and Glut4 mRNA levels in the epididymal adipose and liver.Results:1. Rats in FC and SC groups had impaired glucose and insulin tolerance, and lipiddisorders. They also had higher fasting glucose and insulin lev

44、els, larger fat to body weight ratio, and more fat accumulation in liver than those in NC group. Serum RBP4 levels in FC and SC groups were significantly 1.84 and 1.57 times higher than those in NC group, respectively. And RBP4 mRNA levels in the epididymal adipose of these two groups were also sign

45、ificantly 2.47 and 2.35 times higher than those in NC group, respectively. GlutT4 mRNA levels in the epididymal adipose of these two groups were significantly 1.5 and 1.37 times lower than those in NCgroup, respectively. However, the RBP4 mRNA levels in rat livers between these three groups had no s

46、ignificant difference.2. The weight, fat to body weight ratio and feed efficiency of rats treated byfenofibrate were decreased, and lipid profiles, insulin sensitivity and fat accumulation in the liver in these rats were also improved. Serum RBP4 and RBP4 mRNA levels in the epididymal adipose of rat

47、s in FF group were 20.7% and 56.7% lower than those in FC group; those of rats in SF group were 24% and 52% lower than those in SC group, and GluT4 mRNA levels in the epididymal adipose of the rats received the treatment also increased to some extent, but the RBP4 mRNA levels in rat livers between t

48、he treatment groups and model control groups had no significant difference.3. Simple correlation analyses showed serum RBP4 was associated with RBP4 mRNAlevels in the adipose，and these two factors were both significantly correlated with the parameters, which were related to body fat distribution, gl

49、ucose and lipid metabolism, and insulin resistance, and negatively correlated with GluT4 mRNA levels in the adipose, while RBP4 mRNA levels in the liver were not associated with anyone of those parameters or GluT4 mRNA levels in the adipose.Part 3 conclusion:1. The rat models with insulin resistance

50、 induced by high fat or high sugar diets weresuccessfully founded.2. High fat or high sugar diets could lead to obesity, and stimulate the expression ofRBP4 in the adipose. RBP4 was closely related with glucose and lipid metabolism, visceral fat mass and insulin resistance, which indicated that RBP4

51、 might be a biological marker for metabolic syndrome.3. Fenofibrate increased insulin sensitivity and attenuate RBP4 expression in theadipose by the improvement of lipid disorders and reduction of visceral fat contents.4. In insulin resistance state, adipocytes might be a main source for serum RBP4.

52、However, because we did not assay the RBP4 expressions in other tissues, such as muscle and kidney, we could not exclude the contribution of other tissues to serum RBP4 in the state of insulin resistance, and the influence of PPAR agonist on RBP4 expression in those tissues.Conclusion1. RBP4 was rel

53、ated with the parameters about insulin resistance, such as lipidprofiles and central obesity, and implied that RBP4 could be a serum marker for identifying metabolic syndrome.2. RBP4 was expressed in liver, adipose, muscle, kidney and myocardial tissues, and itwas higher in the liver and kidney, mod

54、erate in the adipose, and lower in muscle and myocardial tissues.3. Fenofibrate increased insulin sensitivity and attenuate RBP4 expression in theadipose by the improvement of lipid disorders and reduction of visceral fat contents.4. In insulin resistance state, adipocytes might be a main source for

55、 serum RBP4.However, because we did not assay the RBP4 expressions in other tissues, such as muscle and kidney, we could not exclude the contribution of other tissues to serum RBP4 in the state of insulin resistance, and the influence of PPAR agonist on RBP4 expression in those tissues.KEY WORDS Ret

56、inol binding protein 4, glucose transporter 4, insulin resistance, fenofibrate第一部分肥胖及2型糖尿病患者血清視黃醇結(jié)合蛋白4水平的臨床研究引言肥胖者的脂肪細(xì)胞肥大及數(shù)量增多，可導(dǎo)致脂肪細(xì)胞分泌的細(xì)胞因子表達(dá)增強或減弱1, 2，如脂聯(lián)素、抵抗素、瘦素、內(nèi)脂素、腫瘤壞死因子（TNF-）、白介素6(IL-6、纖溶酶原激活物抑制劑-1（PAI-1）及血管緊張素原等，從不同層次影響胰島素的效應(yīng)，成為胰島素抵抗形成的主要因素3-10。胰島素抵抗可導(dǎo)致胰島素代償性的高分泌以補償胰島素作用的不足，從而維持血糖的正常，當(dāng)胰島素的分泌

57、不能滿足糖調(diào)節(jié)需要時，即可出現(xiàn)高血糖 11。眾多研究證實胰島素抵抗不僅是糖尿病的病因之一，也是高血壓、血脂異常及動脈粥樣硬化的共同危險因素12, 13。血清視黃醇結(jié)合蛋白4（RBP4）基因位于10q23-24，mRNA 全長941bp ，其編碼的蛋白質(zhì)由201個氨基酸組成，主要由肝臟分泌，新近研究發(fā)現(xiàn)它也是由脂肪細(xì)胞分泌的一種蛋白質(zhì)，參與肥胖與胰島素抵抗(IR發(fā)生機制，但其在人體內(nèi)確切的病理生理功能尚未完全闡明14, 15。胰島素抵抗的患者往往存在低脂聯(lián)素血癥和高游離脂肪酸血癥，它們與RBP4的關(guān)系也仍待深入研究16-18。本研究在糖耐量正常者和2型糖尿病者中測定血清游離脂肪酸、胰島素、脂聯(lián)素

58、和視黃醇結(jié)合蛋白4水平，并分析了RBP4等因子在各組人群間水平的變化，探討它們與肥胖程度、胰島素抵抗、及糖脂代謝之間的關(guān)系。對象與方法一、 對象:在前來本院進(jìn)行常規(guī)體檢以及內(nèi)分泌科門診就診者中，選取131例上海地區(qū)中國人，男性67例，女性64例，年齡2069歲。按WHO(1999糖尿病診斷標(biāo)準(zhǔn)分：正常糖耐量（NGT ）組64例和2型糖尿?。═2DM ）組67例。進(jìn)一步以WHO(1998肥胖診斷標(biāo)準(zhǔn)分組：正常糖耐量正常體重 (NW-NGT 組33例，正常糖耐量超重/肥胖 (OW/OB -NGT 組31例，正常體重2型糖尿病(NW- T2DM 組31例，超重/肥胖2型糖尿病 (OW/OB- T2DM 組36例。研究對象均接受75 g口服葡萄糖耐量試驗(OGTT，本研究采用82.5g 葡萄糖粉（含1分子結(jié)晶水）。除外女性育齡患者如服用避孕藥物者；肝、腎功能異常者；皮質(zhì)醇增多癥；無酮癥酸中毒、冠心病、腎病等糖尿病嚴(yán)重并發(fā)癥；合并高血壓者服用降壓藥血壓控制在140/90 mmHg；除外谷氨酸脫羧酶抗體（GAD ）和酪氨酸磷酸酶抗體（IA