选择性PI3K-Akt通路缺陷参与有生长追赶SGA大鼠胰岛素抵抗的发生机制

目的:研究有生长追赶的小于胎龄个体(SGA)骨骼肌组织胰岛素受体后信号分子的变化,探讨其胰岛素抵抗的发生机制。方法:应用孕鼠全程饮食限制法建立SGA大鼠模型。4周龄有生长追赶SGA(CUG-SGA)和无生长追赶SGA(NCUG-SGA)幼鼠随机分为对照组和胰岛素激发组,并设适于胎龄(AGA)组为对照。测定各组血糖和胰岛素(INS)浓度,计算胰岛素抵抗指数(HOMA-IR)和胰岛β细胞功能指数(HOMA-β)。应用Westernblotting测定各组腓肠肌组织胰岛素受体后信号分子胰岛素受体底物1(IRS1)、蛋白激酶B(Akt)和细胞外信号调节激酶(ERK)的表达及其磷酸化情况。结果:(1)CUG-SGA和NCUG-SGA幼鼠INS和HOMA-IR较AGA组明显增高(均P<0.01),CUG-SGA幼鼠的INS和HOMA-IR显著高于NCUG-SGA组。(2)CUG-SGA幼鼠肌肉组织基础状态下已有p-IRS1表达,INS激发后p-IRS1的表达无显著增加;p-Akt的表达在基础状态和INS激发后均较AGA和NCUG-SGA组显著减低;CUG-SGA基础状态亦有p-ERK表达,INS激发后p-ERK表达显著下降。相关分析显示在基础状态和INS激发状态,SGA幼鼠p-Akt与p-ERK表达呈显著负相关(r=-0.737,P<0.05;r=-0.658,P<0.05)。结论:(1)无论追赶与否,SGA个体生后均呈现胰岛素抵抗,CUG-SGA胰岛素抵抗程度更重。(2)IRS1-PI3K-Akt通路受损是胰岛素抵抗发生的重要的受体后机制;该通路阻断的同时发生Ras-MAPK-ERK通路信号的慢性激活,这可能是胰岛素抵抗同时发生生长追赶的分子机制。     

有生长追赶SGA大鼠促生长素轴的改变

目的: 研究青春前期有生长追赶的小于胎龄(SGA)大鼠促生长素轴的改变,探讨SGA个体生长追赶可能的发生机制。方法: 应用孕鼠全程饮食限制法制备SGA大鼠模型,测定4周龄子鼠尿生长激素(GH)排泄率、血胰岛素样生长因子-1(IGF-1)浓度、肝脏组织IGF-1 mRNA表达和胫骨生长板IGF-1、胰岛素样生长因子-1受体(IGF-1R)表达。结果: 有生长追赶SGA(CUG-SGA)大鼠尿GH水平显著高于无生长追赶SGA(NCUG-SGA)和适于胎龄(AGA)大鼠(P<0.05,P<0.01);血IGF-1水平CUG-SGA显著高于NCUG-SGA组(P<0.01),与AGA组无显著差异。CUG-SGA组肝脏IGF-1 mRNA表达较NCUG-SGA显著增高(P<0.01),与AGA相比无显著差异。胫骨生长板形态学的改变:SGA鼠生长板增殖区每柱细胞数较少,各期软骨细胞排列不规则。 NCUG-SGA组生长板总厚度、各区厚度均较CUG-SGA和AGA组显著降低;CUG-SGA组生长板厚度与AGA组比较无显著差异,但肥大区厚度较NCUG-SGA和AGA组显著增高(P<0.01,P<0.05)。CUG-SGA 组胫骨生长板软骨细胞IGF-1表达较NCUG-SGA显著增多(P<0.01),与AGA组比较无显著差异;3组间IGF-1R表达无显著差异(P>0.05)。结论: SGA大鼠无论生后追赶与否均存在GH/IGF-1轴抵抗,其生后不同的线性生长追赶方式可部分归咎于其抵抗程度。     

小于胎龄儿大鼠胰岛素抵抗与ghrelin水平的关系

Objective To observe the change of insulin sensitivity index (ISI) and ghrelin level, to examine their correlation and to explore the role and significance of ghrelin in insulin resistance (IR) in small for gestational age (SGA) rats. Methods The SGA models were established by starvation method in pregnant SD rats. Experimental rats were grouped by body length and/or body weight 4 weeks after birth.Experiment grouping: ( 1 )SGA group with growth catch-up (Group S 1, n=26 ); (2)SGA group without growth catch-up (Group S2, n=31 ); (3)Normal control group was composed by male rats whose mothers ate and drank freely during pregnancy (Group C, n=27). Body weight and serum ghrelin level was checked 4 weeks after birth. Body weight, serum ghrelin, fasting blood glucose and fasting insulin were tested when the rats were 12 weeks old, and then ISI was calculated. Correlation of all the indexes was analyzed. Results The ISI of 12-week-old SGA rats was significantly decreased as compared to normal control (Group S1:2.00± 0.58, Group S2:2.23±0.58 vs Group C: 3.17±0.54, both P＜0.05). Serum ghrelin level of SGA rats was decreased compared with Group C, but the disparity was not statistically significant [Group S1: (1.357± 0.548) μg/L, Group S2: (1.428±0.714) μg/L vs Group C: (1.843±0.459) μg/L,both P＞0.05 ]. Ghrelin level in 12-week-old rats presented negative correlation with fasting insulin level in blood(r=-0.836,P＜0.01 ), and positive correlation with ISI (r=0.810, P＜0.01). Conclusion The decrease of serum ghrelin level is correlated with IR in adult SGA rats. Low serum level of ghrelin may be the result of IR.     

小于胎龄儿大鼠胰岛素抵抗与ghrelin水平的关系

目的 观察小于胎龄儿(SGA)大鼠胰岛素敏感指数和ghrelin水平的变化及相关关系;探讨ghrelin在SGA导致胰岛素抵抗过程中的作用和意义.方法 采用SD大鼠母鼠妊娠期饥饿法建立SGA大鼠模型,按生后第4周身长和(或)体质量的差异分为有生长追赶组(S1组,n=26)、无生长追赶组(S2组,n=31);以自由饮水及自由进食母鼠娩出之雄性鼠仔为正常对照组(C组,n=27).各组大鼠4周龄时测定体质量及血ghrelin水平,12周龄测定体质量及血ghrelin、空腹血糖、空腹胰岛素并计算胰岛素敏感指数,分析各指标之间的相关性.结果 12周龄SGA大鼠胰岛素敏感指数较C组下降(S1组:2.00±0.58,S2组:2.23±0.58比C组:3.17±0.54,均P＜0.05);血ghrelin水平较C组下降,但差异无统计学意义[S1组:(1.357±0.548)μg/L,S2组:(1.428±0.714)μg/L比C组:(1.843±0.459)μg/L,均P＞0.05].12周龄大鼠血ghrelin水平与空腹血胰岛素水平呈负相关(r=-0.836,P＜0.01),而与胰岛素敏感指数呈正相关(r=0.810,P＜0.01).结论 成年SGA大鼠血ghrelin水平降低与胰岛素抵抗有关,低ghrelin水平可能是胰岛素抵抗的结果.     

从临床诊疗指南及专家共识角度看小于胎龄儿的诊断和治疗

小于胎龄儿围生期患病率及病死率高,成年期发生代谢综合征风险增加,但目前国内尚且缺少小于胎龄儿的诊治共识,本文从定义、危险因素、生长激素治疗及治疗前后的评估与监测、其他治疗及小于胎龄儿的近期和远期并发症等方面进行总结,从而为临床工作中的诊断和治疗提供参考。     

新生儿血清瘦素水平变化与胰岛素和生长激素关系的研究

目的　探讨新生儿血清瘦素来源及其与胰岛素和生长激素的关系。方法　采用放射免疫法检测 80例新生儿静脉血和脐血瘦素水平 ,根据不同胎龄新生儿出生体重值分为大于胎龄儿 (LGA)组 2 8例 ,适于胎龄儿 (AGA)组 36例 ,小于胎龄儿 (SGA)组 16例 ;采用Rohrer′s指数 =出生体重 (g)× 10 0 /身长 (cm) 3 估测新生儿营养状态。结果　早产儿血清瘦素水平明显低于足月儿 (0 6 6± 1 0 3ng/mlvs 3 5 9± 2 16ng/ml,P <0 0 1) ;AGA儿血清瘦素水平 (3 0 6± 0 96ng/m1)明显低于LGA儿(4 0 3± 2 2 2ng/m1) ,而高于SGA儿 (1 13± 1 98ng/m1) ;足月新生儿血清瘦素水平与Rohrer′s指数、新生儿体重、胎龄 ,血清胰岛素、生长激素水平呈显著正相关。结论　新生儿体内瘦素主要来源于自身脂肪组织 ,它反映新生儿的生长营养状态 ,推测瘦素可能通过胰岛素、生长激素共同调节新生儿的生长发育 ,在胎儿和新生儿生长发育中起重要作用。     

冠心病患者血清生长激素与胰岛素间的相关性研究

目的:探讨冠心病患者血清生长激素和胰岛素的变化及相关性意义。方法:采用放射免疫分析测定了120例冠心病患者和50例非冠心病患者的血清生长激素和胰岛素水平,进行对照统计分析。结果:冠心病组血清生长激素水平显著低于对照组(r=3.819,P<0. 01),胰岛素显著高于对照组(t=4.721,P<0. 01),两者间呈显著的正相关(r=0.411,P<0. 01)。Ⅰ、Ⅱ、Ⅲ及Ⅳ级心功能组血清生长激素和胰岛素均呈依次递减趋势,方差检验前者具有非常显著的差异(P<0 05),而后者无显著差异(P>0 05)。出现心力衰竭组血清生长激素显著降低(t=4.411,P<0. 01),血清胰岛素变化无显著意义(P>0. 05)。合并心肌梗死组血清胰岛素水平显著高于无合并组(t=2.752,P<0. 05),生长激素无显著差异(P均>0. 05)。住院死亡组血清生长激素和胰岛素水平均显著低于好转出院组(t=2.191,t=2.227,P<0. 05)。结论:冠心病组血清生长激素显著降低,胰岛素显著升高,随心功能分级递增,生长激素显著递减,合并AMI时,胰岛素显著升高,死亡者则均降低。     

地塞米松诱导大鼠胰岛素抵抗机制的研究

观察了大鼠肌注地塞米松１周和３周后的空腹血糖、血清胰岛素及血浆胰高血糖素ｃＡＭＰ、ｃＧＭＰ水平。结果是经地主松处理后、１周组和３周组的大鼠血清胰岛素明显高于对照组；１周组血糖浓度无显著变化，３周组血糖浓度明显升高；血浆胰高血糖素水平无明显变化，未被高血糖，高胰岛素所抑制；１周组血浆ｃＧＭＰ明显下降；３组间的ｃＡＭＰ浓度差异无统计学意义。     

自发性2型糖尿病大鼠主动脉形态学改变与胰岛素受体底物1mRNA的表达

目的研究自发性2型糖尿病OLETF大鼠在疾病发展的不同阶段，其主动脉组织形态学改变以及胰岛素受体底物-1（IRS-1）mRNA的表达水平，探讨胰岛素抵抗状态下大血管病变的发生机制。方法10只OLETF大鼠随机分别在16周龄与24周龄检杀，10只同种系非糖尿病LETO大鼠为正常对照组。应用光镜和透射电镜观察大鼠主动脉组织形态学改变，原位杂交技术检测主动脉IRS-1 mRNA表达。结果OLETF大鼠在16周龄时主动脉已出现超微结构异常，至24周时其病变程度加重，表现为典型动脉粥样硬化性早期改变；OLETF大鼠在16周和24周时其主动脉IRS-1 mRNA的表达均明显低于同期LETO对照组，分别减少24．6％（P〈0．01）和25．6％（P〈0．001）。结论血管组织胰岛素受体后信号传递分子在基因转录水平即存在异常，导致内皮细胞胰岛素抵抗，可能是糖尿病早期大血管病变危险性增加的机制之一。     

宫内发育迟缓大鼠胰腺肝脏骨骼肌中胰岛素受体底物的表达

目的分析宫内发育迟缓（IUGR）大鼠胰腺、肝脏、骨骼肌中胰岛素受体底物1（IRS-1）和2（IRS-2）mRNA和蛋白水平的表达,探讨IUGR个体发生胰岛素抵抗的机制。方法采用母孕期低蛋白饮食法建立IUGR大鼠模型,以模型鼠产下的仔鼠为IUGR组;以孕期予正常饮食母鼠产下的仔鼠为对照组。应用RT-PCR法检测各组仔鼠在出生后0、3和8周时点胰腺、肝脏和骨骼肌中IRS-1、IRS-2 mRNA表达水平,采用Western blot检测IRS-1和IRS-2蛋白表达水平。检测3和8周时点仔鼠空腹血糖和血清胰岛素水平,计算胰岛素抵抗指数。结果①IUGR组出生后0和3周体重显著低于对照组;8周时点IUGR组体重显著高于对照组。②IUGR组出生后0、3和8周时点胰腺、肝脏IRS-2 mRNA和蛋白表达水平低于对照组;IRS-1 mRNA和蛋白表达水平与对照组差异无统计学意义;骨骼肌IRS-1 mRNA和蛋白表达水平均显著低于对照组;IRS-2蛋白表达水平与对照组差异无统计学意义。③至8周时点,骨骼肌IRS-1 mRNA和蛋白表达水平的下降幅度较胰腺和肝脏组织更为明显;肝脏IRS-2 mRNA和蛋白表达水平的下降幅度较胰腺和骨骼肌组织更为明显。④至8周时点,IUGR组空腹血糖水平与对照组差异无统计学意义,胰岛素水平和空腹胰岛素抵抗指数较对照组显著升高。结论 IUGR大鼠胰腺、肝脏和骨骼肌组织均存在IRS-1或IRS-2 mRNA和蛋白表达水平的下降,可能是发生胰岛素抵抗的机制之一。     

Dysregulation of calcium channels decreases parasecretion in pancreatic β-cells in rats born small for gestational age

Objective: To investigate the role of intrauterine malnourishment in the development and function of pancreatic islet β-cells. Methods: Whole-cell patch clamping was used to record voltage-gated calcium channel (VGCC)-mediated currents. Insulin secretion was detected by measuring capacitance using a sequence of sine wave stimuli. VGCC currents and insulin secretion were measured in the small for gestational age (SGA) group treated with human recombinant growth hormone (hGH). Results: The membrane capacitance in the SGA group (6.4?±?0.9?fF/Pf) was significantly reduced. Calcium current density and peak current density in the SGA group were also markedly decreased, whereas other measurements of calcium channels were unaltered. Treatment with hGH significantly rescued the membrane capacitance, whereas calcium channels were not affected. Conclusion: Our data suggest that decreased β-cell secretion is caused by a decreased expression of calcium channels and reduced calcium currents. hGH restores β-cell secretion in SGA animals, possibly independently of VGCC.     

Decreased maternal circulating hepatocyte growth factor (HGF) concentrations in pregnancies with small for gestational age infants

Our purpose was to evaluate whether maternal and fetal hepatocytegrowth factor (HGF) concentrations in pregnancies with smallfor gestational age (SGA) infants are different from those inpregnancies with appropriate for gestational age (AGA) infants.Maternal and fetal circulating HGF concentrations were comparedbetween 55 pregnancies with AGA infants and 16 pregnancies withSGA infants at birth. HGF concentrations were measured frommaternal and cord venous blood samples using an enzyme-linkedimmunosorbent assay. Umbilical artery blood pH and oxidativepressure (PO₂) were also measured. Maternal circulating HGFconcentrations (0.60 ± 0.35 ng/ml) in pregnancies withSGA infants were significantly lower than those (0.91 ±0.44 ng/ml) in pregnancies with AGA infants (P = 0.012). Therewere no significant differences in fetal circulating HGF concentrationsbetween both groups. No significant differences in umbilicalartery blood pH and PO₂ were found between both groups. Theseresults suggest that the maternal serum circulating HGF concentrationhas a significant role in fetal growth during pregnancy.     

小于胎龄儿脐血脂联素水平测定及其临床意义

目的探讨小于胎龄儿（SGA）脐血脂联素（APN）水平变化及其对新生儿的影响。方法研究对象为SGA和适于胎龄儿（AGA）各30例。采用放射免疫分析法测定脐血和产妇血脂联素水平。用免疫比浊法测定三酰甘油（TG）,总胆固醇（TCH）,低密度脂蛋白胆固醇（LDL-C）,高密度脂蛋白胆固醇（HDL-c）水平。并分析脐血脂联素水平与母血脂联素,体质量指数（IBM）,胎盘重量和血脂水平的相关性。结果1.SGA脐血脂联素水平低于AGA差异有显著性（P〈0.01）;SGA血TG,TCH,LDL-c,HDL-c水平与AGA比较差异均无显著性（P〉0.05）。2.SGA血清脂联素水平与新生儿身长,新生儿体质量指数BMI,胎盘重量,脐血TG呈显著正相关（r=0.386,0.431,0.365,0.231,P〈0.05）,与母血脂联素水平,孕前和分娩时产妇IBM无相关性（P〉0.05）。结论小于胎龄儿具有较低血清脂联素水平,测定脐血脂联素水平有助于判断SGA的发展趋势。     

抚触对足月小样儿早期生长发育影响的临床研究

目的探讨抚触对足月小样儿生长发育的影响。方法将89例符合诊断标准的足月小样儿随机分成抚触组和对照组,比较2组患儿1w内体重的变化和28天内新生儿神经测定等发育指标。结果抚触组1w内生理性体重恢复速率快于对照组;新生儿神经行为评分高于对照组（P〈0.05）。结论抚触对足月小样儿早期体格和神经系统发育有明显的促进作用。     

Insulin-like growth factor 1 gene (CA)n repeats and a variable number of tandem repeats of the insulin gene in Brazilian children born small for gestational age

OBJECTIVE:

To investigate the influence of (CA)n repeats in the insulin-like growth factor 1 gene and a variable number of tandem repeats of the insulin gene on birth size in children who are small or adequate-sized for gestational age and to correlate these polymorphisms with serum insulin-like growth factor 1 levels and insulin sensitivity in children who are small for gestational age, with and without catch-up growth.

PATIENTS AND METHODS:

We evaluated 439 infants: 297 that were adequate-sized for gestational age and 142 that were small for gestational age (66 with and 76 without catch-up). The number of (CA)n repeat in the insulin-like growth factor 1 gene and a variable number of tandem repeats in the insulin gene were analyzed using GENESCAN software and polymerase chain reaction followed by enzymatic digestion, respectively. Clinical and laboratory data were obtained from all patients.

RESULTS:

The height, body mass index, paternal height, target height and insulin-like growth factor 1 serum levels were higher in children who were small for gestational age with catch-up. There was no difference in the allelic and genotypic distributions of both polymorphisms between the adequate-sized and small infants or among small infants with and without catch-up. Similarly, the polymorphisms were not associated with clinical or laboratory variables.

CONCLUSION:

Polymorphisms of the (CA)n repeats of the insulin-like growth factor 1 gene and a variable number of tandem repeats of the insulin gene, separately or in combination, did not influence pre- or postnatal growth, insulin-like growth factor 1 serum levels or insulin resistance.     

Effect of gestational weight gain on insulin resistance mediated by serum adipokine concentrations in advanced maternal age

IntroductionWith the implementation of the universal two-child policy, the number of pregnant women of advanced maternal age (AMA) will increase steadily. We aimed to investigate whether the effect of gestational weight gain on insulin resistance (IR) before delivery was mediated by serum adipokine concentrations in AMA.Material and methodsThis cross-sectional study included 80 pregnant women of AMA recruited consecutively before delivery from the Department of Obstetrics and Gynecology between August 2016 and July 2017. At delivery, maternal weight during the third trimester was recorded and serum adipokines were measured. IR was calculated using the homeostasis model assessment 2 (HOMA2) method.ResultsWeight gain (WG) during the third trimester was positively associated with serum leptin concentrations (r = 0.34, p = 0.0018) and HOMA-IR indices (r = 0.25, p = 0.025), but not related with serum concentration of adiponectin (r = 0.12, p = 0.28). WG during the third trimester and serum concentration of leptin were independently associated with the level of HOMA-IR by multivariate analysis. Subsequently, according to mediation analysis, the association between WG during the third trimester and HOMA-IR mediated by serum leptin concentrations was statistically significant (z = 1.588, p < 0.05).ConclusionsTaken together, our findings suggest that the relationship between WG during the third trimester and IR was mediated by serum leptin concentrations in AMA, but not serum adiponectin concentrations.