【作者】 康怡；

【导师】 陆菊明；

【作者基本信息】 中国人民解放军军医进修学院 ， 内科学， 2009， 博士

【摘要】 目的采用CGMS系统研究不同糖调节受损人群的动态血糖波动特征及其与氧化应激和胰岛功能的相关性。方法1、2008年1月至7月选取北京地区受试者81例,按照美国糖尿病学会（ADA）2003年标准分为单纯空腹血糖受损（I-IFG）组12例,单纯餐后血糖受损（I-IGT）组19例,空腹血糖受损合并糖耐量低减状态（IFG/IGT）组11例,新诊断2型糖尿病（T2DM）组21例,正常糖耐量（NGT）组18例,所有受试对象均行72h动态血糖监测（CGMS）,分析其各项临床指标和CGMS动态血糖数据。2、根据连续两次OGTT结果,选取NGT组15例,糖尿病前期（IGR）47例,T2DM组36例。选取平均血糖波动幅度评价血糖波动情况;行CGMS第48～72小时留取24h尿,采用酶联免疫吸附法检测8-异前列腺素F_2α(8-isoPGF_2α)评价氧化应激水平;留取空腹和OGTT负荷后2小时静脉血监测血浆胰岛素及C肽水平,采用HOMA稳态模型胰岛素抵抗指数（HOMA-IR）反映胰岛素敏感性,采用HOMAβ细胞功能指数（HBCI）以及胰岛素分泌功能指数(ΔI₁₂₀/ΔG₁₂₀)评价糖负荷后胰岛β细胞分泌功能。3、2型糖尿病组给予“重组赖脯胰岛素25”治疗12周,其间定期随访、指导生活方式干预并调整胰岛素用量。对血糖波动、氧化应激、胰岛功能及胰岛素抵抗参数和各项代谢指标的变化行方差分析,并对其影响因素行相关分析及多元逐步回归分析。结果1、不同IGR人群血糖波动特征:①日内血糖波动:NGT、I-IFG、I-IGT、IFG/IGT至T2DM组的最大血糖波动幅度（LAGE）、平均血糖（MBG）和血糖水平标准差（SDBG）依次升高。I-IGT的平均血糖波动幅度（MAGE）（3.16±1.15）mmol/L较NGT（1.62±0.49）mmol/L高,较T2DM（5.23±1.88）mmol/L低（P＜0.05）;IFG/IGT的有效血糖波动频率（FGE）（5.54±2.50）较NGT（6.06±3.42）低,较T2DM（4.81±1.83）高。糖尿病前期3组间I-IGT组MAGE（3.16±1.15）mmol/L最高,FGE（4.89±1.79）最低。②日间血糖波动:与NGT组（0.76±0.29）mmo/L相比,I-IGT（1.06±0.36）mmol/L、IFG/IGT（1.16±0.39）mmol/L和T2DM（1.95±0.95）mmol/L组的日间血糖平均绝对差依次升高（P＜0.05）。③不同糖调节受损人群血糖波动特征:I-IFG组空腹血糖受损程度最重,餐后高峰以IFG/IGT组为著。血糖水平曲线由低至高依次为NGT、I-IGT、IFG/IGT、I-IFG、T2DM组。④受试者HbA_1C＜7%时,空腹血糖曲线几乎重合,餐后血糖曲线略微分开;HbA_1C7.0%～7.9%时,餐后高峰明显上升;HbA_1C≥8%时,空腹曲线明显上移,餐后波动继续升高。2、血糖波动与氧化应激相关性:①基线时T2DM组24h尿游离8-isoPGF_2α分泌率(8-isoPGF_2α/Cr)为（1706±477）pg/mg,较糖尿病前期组（（216±65）pg/mg）和正常糖耐量组（（269±60）pg/mg）升高,差异有统计学意义（F=27.304,P＜0.05）。②T2DM组经“重组赖脯胰岛素25”干预后,24h尿8-isoPGF_2α/Cr、平均血糖波动幅度、糖化血红蛋白、甘油三酯与干预前比较分别降低34.53%,31.81%,18.50%和28.79%,差异有统计学意义（F值分别为6.108、18.378、39.322和5.942,P均＜0.05）;此外,收缩压、舒张压、空腹血糖、餐后2h血糖与干预前比较显著下降（F值分别为7.879、11.684、38.952和61.207,P均＜0.01）。③Pearson相关分析显示24h尿8-isoPGF_2α/Cr与MAGE呈显著相关（r=0.593,P＜0.01）;而与HbA_1C无相关（r=0.186,P＞0.05）;④以24h尿8-isoPGF_2α/Cr为因变量,以Pearson相关分析与其有相关性的变量为自变量进行多元逐步回归分析,只有平均血糖波动幅度和高密度脂蛋白胆固醇进入最终方程（决定系数r²分别为0.354和0.346,P均＜0.01）;偏相关分析与上述结果一致。3、血糖波动与胰岛分泌功能和胰岛素抵抗的相关性:①T2DM组的HOMA胰岛素抵抗指数（HOMA-IR）分别是IGR组和NGT组的2.7倍和3.8倍（F=4.07,P＜0.05）;②校正HOMA-IR后,T2DM组HOMAβ细胞功能指数（HBCI/IR）为NGT组的17.2%,IGR组的25.5%（F=21.19,P＜0.01）;T2DM组的空腹β细胞功能指数（FBCI/IR）为NGT组的34.4%,IGR组的42.9%（F=89.62,P＜0.01）;T2DM组ΔI120/ΔG120/IR为NGT组的6.2%,为IGR组的15.5%（F=21.19,P＜0.01）;③将Pearson相关分析与氧化应激、血糖波动相关的各项指标行偏相关分析,结果仅FBCI/IR与8-isoPGF_2α/Cr的相关性保留,HBCI、HBCI/IR、△I120/△G120和空腹C肽与8-isoPGF_2α/Cr的相关性经FBCI/IR调整后消失（r值分别为0.20、0.27、-0.03和0.05,P＞0.05）;而MAGE仅与FBCI/IR、△I120/△G120具有统计学意义上的相关性,HOMA-IR、HBCI、HBCI/IR、△I120/△G120/IR与MAGE的相关性经FBCI/IR调整后消失（r值分别为0.03、-0.11、0.21和-0.05,P＞0.05）;多元逐步回归分析支持上述结果;④Pearson相关分析提示HOMA-IR与午餐前血糖关系最为密切;晚餐后峰值血糖主要反映胰岛β细胞分泌功能;基础胰岛分泌功能主要与晚餐后峰值血糖、早餐前血糖和3am血糖相关;而糖负荷后胰岛分泌的储备功能主要与早餐后2h血糖相关;⑤按CGMS特殊时点血糖四分位数水平分组,并行方差分析对比组间反映胰岛功能和胰岛素抵抗等参数的差异,结果显示早餐前血糖、早餐后2小时血糖和午餐前血糖的参考阈值分别是5.8mmol/L、7.9mmol/L和7.3mmol/L;而晚餐后峰值血糖阈值根据评价指标不同略有差异,当其大于8.1mmol/L时,HBCI/IR显著下降;而9.8mmol/L则是评价调整了胰岛素抵抗因素的胰岛β细胞基础分泌功能的推荐界值（P值均＜0.01）。结论①随着糖调节受损程度的加重,日内血糖波动、日间血糖波动和氧化应激水平逐渐增加;②正常人血糖波动幅度小,频率高;T2DM餐后血糖波动幅度大,有效波动频率低;③I-IFG组的血糖波动特征最接近于NGT,而I-IGT组最接近于T2DM;④在糖尿病前期阶段餐后血糖受损明显早于空腹;⑤2型糖尿病氧化应激活化程度与血糖波动和部分血脂代谢相关;⑥经胰岛素干预后,血糖波动幅度下降,氧化应激反应减轻;⑦糖尿病前期和2型糖尿病均有不同程度的胰岛β细胞分泌功能减退,考虑了胰岛素抵抗因素的影响后这种改变更为明显;⑧糖尿病急性血糖波动增加,通过氧化应激这一关键环节加重对胰腺β细胞分泌功能的损伤;⑨可以根据特殊时点的血糖水平初步评估糖尿病患者相对占优势的病理生理进展阶段,对口服降糖药物的选择具有参考意义。更多还原

【Abstract】 Objective To analyze correlation of oxidative stress activation,pancreatic islet function and acute glucose fluctuations in subtypes of impaired glucose regulation by continuous glucose monitoring system（CGMS）.Methods 1.From January to July in 2008,according to ADA 2003 diagnostic criteria,81 individuals were divided into 4 groups:normal glucose tolerance（NGT,n=18）,isolated impaired fasting glycemia（I-IFG,n=12）,isolated impaired glucose tolerance（I-IGT,n=19）, combined IFG/IGT（n=11）,and newly diagnosed type 2 diabetes mellitus（T2DM, n=21）.And then continuous glucose monitoring system（CGMS） was used for 72 hours to monitor the blood glucose（BG） level before drug intervention.2. Assessed by oral glucose tolerance test（OGTT） repeated twice,98 individuals were divided into 3 groups:NGT（n=15）,impaired glucose intolerance（IGR,n=47） and 36 T2DM.And their BG levels were monitored by CGMS for three consecutive days.Intraday glycemic excursions were assessed by mean amplitude of glucose excursions（MAGE）;From 48h to 72h during CGMS period,24h urine samples were collected and free 8-iso prostaglandin F_2α(8-isoPGF_2α) were measured by ELISA to evaluate oxidative stress.Fasting and OGTT 2 hours venous blood samples were collected to measure plasma insulin and C peptide levels.Moreover,HOMA insulin resistance index（HOMA-1R） were calculated to evaluate insulin sensitive.HOMAβ-cell function index（HBCI） and△I₁₂₀/△G₁₂₀ to evaluate the insulin response to a stimulus.Repeated CGMS were given after three months Lispro 25 interventions in T2DM group.Periodical interview included life style intervention directions and insulin regulations.Glucose excursions,oxidative stress,insulin index and other metabolic readouts before and after intervention were compared by one-way ANOVA.Possible factors effected on the deterioration of pancreatic islet function were analyzed by Pearson correlation coefficient and multivariate stepwise regression.Results 1. Characteristics of glycemic excursion in different subtypes of impaired glucose intolerance:①The levels of largest amplitude of glycemic excursions（LA（?）E）, mean blood glucose（MBG）,and standard deviation of mean level of blood glucose fluctuation（SDBG） increased gradually with the deterioration of glucose tolerance.The MAGE readout of the I-IGT group was（3.16±1.15） mmol/L, significantly higher than that of the NGT group[（1.62±0.49） mmol/L,P＜0.05], and significantly lower than that of the T2DM group[（5.23±1.88） mmol/L, P＜0.05].The level of frequency of glucose excursion（FGE） decreased along with the decrease of glucose tolerance:NGT group[（6.06±3.42）]＞IGT/IFG group [（5.54±2.50）]＞T2DM group[（4.81±1.83）].Among the three components of IGR,the I-IGT group showed highest MAGE（3.16±1.15） mmol/L and lowest NGE level（4.89±1.79）.②The level of absolute mean of daily difference （MODD） increased in the following order:NGT group[（0.76±0.29） mmol/L], I-IGT group[（1.06±0.36） mmol/L],IFG/IGT group[（1.16±0.39） mmol/L], and T2DM group[（1.95±0.95） mmol/L]（all P＜0.05）.③The fasting glucose level deteriorated the most rapidly in the I-IFG group,while it reached the highest postprandial peak in the IFG/IGT group.The blood glucose curve increased along the order of NGT,I-IGT,IFG/IGT,I-IFG,and T2DM.④When the level of glycosylated hemoglobin A1c(HbA_1C) level was less than 7%,the fasting phase of curve virtually coincided with each other among individual groups with different HbA_1C levels;however,the postprandial peak separated slightly.When the HbA_1C level was between 7.0%and 7.9%,the postprandial peaks of individual groups with different HbA_1C levels dispersed markedly.When the HbA_1C level was higher than 8%,the fasting blood glucose curve moved upwards significantly with increasing postprandial excursion.2.Correlation of oxidative stress activation and acute glucose fluctuations:①Mean（SD） urinary excretion rates of 8-isoPGF_2α（1706±477）pg/mg of creatinine)in T2DM group significantly increased compared with it in IGR group（（216±65）pg/mg） and NGT group（（269 4-60）pg/mg）（F=27.304,P＜0.05）.And levels of MAGE（6.04mmol/L） in T2DM group also elevated compared with it in IGR group（（2.70±1.22）mmol/L）) and NGT group（（1.73±0.50）mmol/L）)（F=67.729,P＜0.05）.②With Lispro 25 interventions in T2DM group,urinary excretion rates of 8-isoPGF_2α,MAGE, glycosylated hemoglobin(HbA_1C) and triglyceride（TG） read（?）ts decreased by 34.53%,31.81%,18.50%and 28.79%respectively（F values were 6.108,18.378, 39.322 and 5.942,all P＜0.05）.Moreover,the level of systolic blood pressure（SBP）,diastolic blood pressure（DBP）,fasting blood glucose（FBG） and 2h postprandial blood glucose（2hPBG） also significantly decreased（F values were 7.879,11.684,38.952 and 61.207 respectively,all P＜0.01）.③Pearson correlation analysis:urinary excretion rates of 8-isoPGF_2α was positively correlated with MAGE（r=0.593,P＜0.01）.No significant correlation were found between HbA_1C and urinary excretion rates of 8-isoPGF_2α（r=0.186,P＞0.05）;④With urinary excretion rates of 8-isoPGF_2α as dependent,and positive correlation factors in Pearson correlation analysis as independent,multivariate stepwise regression analysis showed MAGE and HDL-c entered final two models（r² value was 0.354 and 0.346 respectively,all P＜0.01）;and same results were found by Partial correlation analysis.3.Correlation of Pancreatic Islet Function and Acute Glucose Fluctuations:①HOMA-IR of T2DM group were 2.7 times and 3.8 times higher than that of IGR group and NGT group respectively（F=4.07,P＜0.05）.②With corrected by HOMA-IR,HBCI/IR of T2DM group were 17.2 percent and 25.5 percent as that of NGT group and IGR group respectively（F=21.19,P＜0.01）. And FBCI/IR of T2DM group were 34.4 percent and 42.9 percent as that of NGT group and IGR group respectively（F=89.62,P＜0.01）.Moreover,△I₁₂₀/△G₁₂₀/IR of T2DM group were 6.2 percent and 15.5 percent than that of NGT group and IGR group respectively（F=21.19,P＜0.01）.③Significant correlation by Partial correlation analysis was found only between FBCI/IR and 8-isoPGF_2α/Cr,but not between HBCI,HBCI/IR,△I120/△G120,fasting C peptide and 8-isoPGF_2α/Cr after FBCI/IR controlled analysis（r value was 0.20,0.27,-0.03 and 0.05 respectively,P＞0.05）.Furthermore,statistical significant was also found in the correlation between FBCI/IR,△I120/△G120 and MAGE, but not between HOMA-IR,HBCI,HBCI/IR,△I120/△G120/IR and MAGE after FBCI/IR controlled analysis（r value was 0.03,-0.11,0.21 and -0.05 respectively, P＞0.05）.These conclusions were further evaluated and validated by multivariate stepwise regression analysis.④Pearson correlation analysis:HOMA-IR was positively correlated with blood glucose before lunch with most significance; dinner postprandial glucose spike mainly reflected islet beta cell secretion function.And there were significantly correlation between basal islet function and dinner postprandial glucose spike,fasting blood glucose and 3am blood glucose; Stimulated pancreatic islet function had correlation with blood glucose two hours after breakfast.⑤All subjects were grouped by the level of quartile blood glucose in special time and insulin resistance and pancreatic islet function indices were compared by one-way ANOVA.Then the reference threshold of fasting blood glucose,two hours after breakfast and blood glucose before lunch were 5.8mmol/L,7.9mmol/L and 7.3mmol/L respectively.The cut-off points of dinner postprandial glucose spike depending on the index.It was 7.3mmol/L to assess HBCI/IR and 8.1mmol/L to assess FBCI/IR（all P＜0.01）.Conclusion①With the deterioration of glucose regulation,the intraday and day-to-day blood glucose excursion levels became increasingly fluctuant,therefore,the oxidative stress became more activated.②The amplitude of glycemic excursion was lower in the NGT group than in the T2DM group,however,the frequency of glycemic excursion was higher in the NGT subject than that in the T2DM subjects.The glucose excursion profile of the IGR subjects was between the NGR and T2DM subjects.③The characteristics of glucose excursion of the I-IGT group were similar to those of the T2DM group,and the characteristics of the I-IFG group was similar to those of the NGT group.④The loss of postprandial glycemic control preceded evident deterioration in fasting phase of IGR.⑤The activation of oxidative stress in T2DM were positive correlation with glucose fluctuations and some lipoprotein metabolism.⑥With insulin treatment,glucose excursions and oxidative stress were both improved obviously.⑦Pre-diabetes and type 2 diabetes had various degrees of pancreaticβ-cell secreting dysfunction,and this tendency became more obvious with insulin resistance factors taken into account.⑧Acute glucose fluctuations may contribute to pancreaticβ-cell secreting dysfunction through activation of oxidative stress in T2DM.⑨According to the level of blood glucose in special time,we had a preliminary evaluation of diabetic patients’ pathophysiology conditions and it may be helpful to choose oral hypoglycemic agents.更多还原