PDGF与糖尿病肾病

血小板源性生长因子(PDGF)主要通过自分泌、旁分泌及内分泌作用参与糖尿病肾病(DN)的发生、发展。PDGF-BB在糖尿病肾脏局部高表达，与转化生长因子协同促进肾小球系膜细胞增生及细胞外基质的合成，导致糖尿病肾小球硬化的发生，而应用阻止PDGF-BB表达的方法则可有效防止DN的发生。     

PDGF与糖尿病肾病

血小板源性生长因子(PDGF)主要通过自分泌、旁分泌及内分泌作用参与糖尿病肾病(DN)的发生、发展.PDGF-BB在糖尿病肾脏局部高表达,与转化生长因子协同促进肾小球系膜细胞增生及细胞外基质的合成,导致糖尿病肾小球硬化的发生,而应用阻止PDGF-BB表达的方法则可有效防止DN的发生.     

早期生长反应因子-1与糖尿病肾病

早期生长反应因子-1(Egr-1)是一种具有锌指结构的转录因子,能被多种刺激因素诱导,并能调控下游多种基因的表达,参与细胞的生长、分化、增殖和凋亡.研究发现,高血糖可引起肾脏Egr-1表达增加,促进系膜细胞增殖、血管内皮功能损伤、细胞外基质积聚、转化生长因子-β过表达和肾纤维化,表明Egr-1与糖尿病肾病的发生、发展密切相关.     

TGF-β1、PDGF-BB和糖尿病肾病

转化生长因子β1和血小板源性生长因子BB均为多功能细胞因子，糖尿病肾病时二者在肾脏局部的表达明显增强。转化生因子β和血小板源性生长因子BB均可使系膜区细胞外基质成分合成增多、降解减少，在肾小球、肾小管间质硬化中起重要作用。二者相互促进又相互制约，在糖尿病肾病发病机制中作用日益受到人们的重视。     

胰岛素样生长因子-1与糖尿病肾病关系的研究进展

胰岛素样生长因子-1具有致肾脏肥大和肾小球高滤过,以及使肾脏系膜细胞增生和基质堆积等作用,在糖尿病肾病的发生发展中起一定的促进作用。其机制可能与胰岛素样生长因子系统的紊乱有关。(林栋摘)     

转化生长因子β1和糖尿病肾小球硬化关系的研究进展

肾小球硬化是糖尿病肾病的重要特征。近年发现转化生长因子β1在糖尿病肾小球硬化的发生机制中起着重要作用,是多种致病因子作用的最终途径,通过促进肾脏系膜细胞肥大和细胞外基质产生,抑制细胞外基质降解,损害足细胞,参与糖尿病肾小球硬化的发生和发展。研究转化生长因子β1及其上调的影响因素和干预措施,有助为糖尿病肾小球硬化的防治提供新的理论基础和临床指导。     

结缔组织生长因子与糖尿病肾病

结缔组织生长因子(CTGF)是新近发现的具有促进细胞增殖和细胞外基质(ECM)积聚等生物活性的细胞因子,被认为是转化生长因子(TGF)-β的下游效应分子。糖尿病时高糖、糖基化终产物、机械压力、TGF-β均可使肾组织CTGF表达增加,促进ECM的形成,参与糖尿病肾病(DN)肾脏纤维化的发生。CTGF可能成为DN治疗研究的新靶点。     

胰岛素样生长因子-1系统与糖尿病肾病

糖尿病(DM)状态下,肾脏胰岛素样生长因子-1(IGF-1)浓度升高。IGF-1具有刺激系膜基质成分生成,减少系膜细胞中胶原蛋白降解,诱导肾脏中缓激肽和肾素基因表达,并促进系膜细胞产生一氧化氮,增加系膜细胞对葡萄糖的摄入等作用。IGF-1的生物学行为是通过IGF-1受体来介导的,而IGF-1与受体间的相互作用是由IGF-1结合蛋白(IGFBP)来调节。DM时,肾脏IGFBP、IGF-1受体水平均发生变化。IGFs通过一个包括IGF-1、IGFBP以及IGF-1受体的复杂系统,在糖尿病肾病的发生发展中起着重要作用。     

高糖对系膜细胞基质金属蛋白酶的影响

系膜区基质积聚是糖尿病肾病的病理特征之一，它主要由于基质合成与降解通路的精细平衡失调。近年来研究发现高糖能通过对系膜细胞基质金属蛋白酶类(MMPs)基因转录、活化及抑制等三方面复杂的调控而降低其基质降解活性，调控过程可能由转化生长因子(TGF)-β、胰岛素样生长因子(IGF)-1和基质糖化等介导。系膜细胞MMPs活性下降致系膜区基质降解减少可能是引起系膜区基质积聚导致糖尿病肾病的重要原因之一。     

结缔组织生长因子在糖尿病肾病中的作用研究进展

结缔组织生长因子具有促进细胞增殖分化、血管生成、基质合成积聚等作用,在糖尿病肾病导致肾小球硬化和肾小管间质纤维化的过程中起关键性作用.通过干预结缔组织生长因子可以缓解糖尿病肾病肾脏纤维化的进展.本文对结缔组织生长因子在糖尿病肾病发生发展中的作用进行综述.     

Intestinal hormones and growth factors： Effects on the small intestine

There are various hormones and growth factors which may modify the intestinal absorption of nutrients, and which might thereby be useful in a therapeutic setting, such as in persons with short bowel syndrome. In part I, we focus first on insulin-like growth factors, epidermal and transferring growth factors, thyroid hormones and glucocorticosteroids. Part Ⅱ will detail the effects of glucagon-like peptide （GLP）-2 on intestinal absorption and adaptation, and the potential for an additive effect of GLP2 plus steroids.     

Regulation of fetal growth: consequences and impact of being born small

The first trimester of pregnancy is the time during which organogenesis takes place and tissue patterns and organ systems are established. In the second trimester the fetus undergoes major cellular adaptation and an increase in body size, and in the third trimester organ systems mature ready for extrauterine life. In addition, during that very last period of intrauterine life there is a significant increase in body weight. In contrast to the postnatal endocrine control of growth, where the principal hormones directly influencing growth are growth hormone (GH) and the insulin-like growth factors (IGFs) via the GH-IGF axis, fetal growth throughout gestation is constrained by maternal factors and placental function and is coordinated by growth factors. In general, growth disorders only become apparent postnatally, but they may well be related to fetal life. Thus, fetal growth always needs to be considered in the overall picture of human growth as well as in its metabolic development.     

宫内发育迟缓与胰岛素样生长因子及其结合蛋白关系的研究

为探讨宫内发育迟缓（IUGR）的发生机制,检测了86例新生儿脐血胰岛素样生长因子－1（IGF－1）、胰岛素样生长因子结合蛋白－3（IGFBP－3）水平,并分析上述指标变化与胎儿期生长的关系。将86例新生儿分为两组,IUGR（即小于胎龄儿）组22例,适于胎龄儿（AGA）组64例,采用竞争性放射免疫分析法（RIA）测定两组脐血IGF－1水平,非竞争性免疫放射分析法（IRMA）测定IGFBP－3水平。结果显示,与AGA组相比,IUGR组脐血IGF－1和IGFBP－3水平显著降低（P＜0．001）;IGF－1水平随胎龄及出生体重增加而增加（P＜0．01）;IGFBP－3水平与胎龄及出生体重呈相关（P＜0．01）;IGF－1与IGFBP－3呈正相关（P＜0．01）。认为IUGR与IGF－1及其结合蛋白密切相关,不论何种原因引起的IUGR,其脐血IGF－1、IGFBP－3水平均低,IGF－1水平下降与IGFBP－3下降相伴随;脐血IGF－1、IGFBP－3水平与胎龄及出生体重呈正相关,随着胎龄的增加和出生体重的增长,IGF－1、IGFBP－3水平不断升高。     

Serum levels of growth hormone-binding protein and insulin-like growth factor I in children and adolescents with Type 1 (insulin-dependent) diabetes mellitus

Summary Serum levels of insulin-like growth factor I are reduced in patients with Type 1 (insulin-dependent) diabetes mellitus. To evaluate the role of the hepatic growth hormone receptor in the decreased serum concentrations of insulin-like growth factor I, serum levels of the high affinity growth hormone-binding protein, which is qualitatively and quantitatively related to the hepatic growth hormone receptor, and of insulin-like growth factor I were measured in 70 children and adolescents with Type 1 diabetes and 105 healthy control children. Analysis of variance revealed a significant negative effect of Type 1 diabetes on serum levels of the growth hormone-binding protein and of insulin-like growth factor I. In the diabetic patients, serum levels of the growth hormone-binding protein were positively related to body mass index and to insulin dose per kg body weight, and were not influenced by pubertal stage, gender, or plasma levels of haemoglobin A_1c. Serum levels of insulin-like growth factor I increased during early puberty reaching peak levels at midpuberty and decreasing thereafter. No relationship was found between serum levels of growth hormone-binding protein and of insulin-like growth factor I. Our data suggest that decreased liver somatogenic receptor levels, as reflected by the concentrations of circulating growth hormone-binding protein, play a minor role in the suppressed concentrations of circulating insulin-like growth factor I. Post-growth hormone receptor defects or changes in the insulin-like growth factor binding proteins probably contribute more to the lower serum levels of insulin-like growth factor I.     

Successful prolonged use of recombinant human insulin-like growth factor-1 in a child with cystic fibrosis

Growth failure is a common and complicated process in children with cystic fibrosis (CF). Growth hormone, which is becoming a more commonly used agent in such patients, has demonstrated beneficial effects aside from increased growth velocity. Recently, insulin-like growth factor-1 has gained significant attention in the understanding of growth failure in children with CF. We report the successful prolonged use of recombinant human insulin-like growth factor-1 in an adolescent boy with CF, who demonstrated significant clinical benefits from the therapy.     

Growth Hormone Increases the Mass,the Collagenous Proteins,and the Strength of Rat Colon

The effect of growth hormone treatment on the left colon was investigated in 4-month-old Wistar rats. The animals were injected with saline (controls) or biosynthetic human growth hormone (b-hGH) in doses of 1.0 and 5.0 mg b-hGH/kg/day for 30 days. The total body weight of the rats injected with 1.0 mg b-hGH/kg/day did not differ from that of the control group, whereas the body weight of the rats injected with 5.0 mg b-hGH/kg/day was increased by 37% compared with the control group. The colonic dry weight per unit length was increased by 57% and 46% by 1.0 mg and 5.0 mg b-hGH/kg/day, respectively. The defatted dry weight was increased by 52% and 44%, respectively. The hydroxyproline content per unit length was increased by 31% and 23%, respectively. Furthermore, the biomechanical strength was increased by the b-hGH injections. No difference between the two b-hGH doses was found in any of the data.     

From the Cover: Ramification of stream networks

The geometric complexity of stream networks has been a source of fascination for centuries. However, a comprehensive understanding of ramification—the mechanism of branching by which such networks grow—remains elusive. Here we show that streams incised by groundwater seepage branch at a characteristic angle of 2π/5 = 72°. Our theory represents streams as a collection of paths growing and bifurcating in a diffusing field. Our observations of nearly 5,000 bifurcated streams growing in a 100 km² groundwater field on the Florida Panhandle yield a mean bifurcation angle of 71.9° ± 0.8°. This good accord between theory and observation suggests that the network geometry is determined by the external flow field but not, as classical theories imply, by the flow within the streams themselves.