The prevention or treatment of age-related osteoporosis in the elderly by systemic recombinant growth factor therapy (rhIGF-I or rhTGFβ): a perspective

Boonen S, Broos P, Dequeker J, Bouillon R (Department of Internal Medicine, Division of Geriatric Medicine, the Arthritis and Metabolic Bone Disease Research Unit, the Department of Traumatology and Emergency Surgery and the Laboratory for Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, Leuven, Belgium). The prevention or treatment of age-related osteoporosis in the elderly by systemic recombinant growth factor therapy (rhIGF-I or rhTGFβ): a perspective (Review). J Intern Med 1997; 242 : 285–90.
Both insulin-like growth factor-I (IGF-I) and transforming growth factor β (TGFβ) have powerful modulatory effects in a variety of tissues. A major target of action is the skeletal system, where they enhance bone formation and decrease matrix degradation, thus playing a part in the maintenance of bone mass. Because of the potent mitogenic effect of these agents on osteoblasts, recombinant IGF-I (rhIGF-I) and recombinant TGFβ (rhTGFβ) have potential as drugs to stimulate bone formation in the prevention and treatment of osteoporosis. Using biochemical markers, subcutaneous rhIGF-I therapy has been shown to increase bone turnover and bone formation in nonosteoporotic older people. However, a corresponding increase in bone mass has not yet been documented nor have there been reports yet on the effects of systemically administered rhTGFβ in humans. Further investigation is required to define the clinical potential of rhIGF-I and rhTGFβ as therapeutic agents in age-related osteoporosis.     

转化生长因子-β及胰岛素样生长因子-Ⅰ修复关节软骨缺损的实验观察

目的观察转化生长因子-β（transforming growth factor-β,TGF-β）、胰岛素样生长因子-Ⅰ（insulin—like growth factor-Ⅰ,IGF-Ⅰ）对关节软骨缺损修复的作用。方法采用组织工程方法制备骨基质明胶（BMG）软骨细胞移植物。将40只4月龄的新西兰兔随机分为TGF-β组、IGF-Ⅰ组、TGF-β联合IGF-Ⅰ组、空白对照组（前三组为实验组）。各组制备关节软骨缺损模型,实验组兔膝关节腔注射对应等量人重组蛋白,对照组注射等量盐水。术后行组织学观察及免疫组化检测。结果TGF-β联合IGF-Ⅰ组软骨细胞生长较快,术后24周修复的软骨组织HE染色与正常关节软骨一致,软骨细胞呈柱状排列,免疫组化见Ⅱ型胶原染色较深;TGF-β组、IGF-Ⅰ组术后24周部分软骨细胞呈柱状排列,免疫组化见Ⅱ型胶原染色较浅;空白对照组未修复。结论联合应用TGF-β及IGF-Ⅰ可较好促进关节软骨缺损修复,其作用优于两者单独应用。     

Hepatocyte growth factor concentration in the early second-trimester amniotic fluid does not predict fetal growth at birth.

The purpose of this study was to evaluate whether hepatocyte growth factor (HGF) concentrations in the early second-trimester amniotic fluid predict fetal growth at birth. HGF and insulin-like growth factor-I (IGF-I) concentrations in the early second-trimester amniotic fluid were measured in 12 pregnancies with small for gestational age (SGA) infants, 84 pregnancies with appropriate for gestational age (AGA) infants, and eight pregnancies with large for gestational age (LGA) infants. HGF concentrations were measured from the early second-trimester amniotic fluid samples using an enzyme-linked immunosorbent assay. IGF-I concentrations were measured from the early second-trimester amniotic fluid samples using an immunoradiometric assay. Maternal age in AGA group (34.2 +/- 5.5 years) was significantly lower than in SGA (37.9 +/- 3.0 years) and LGA (37.6 +/- 3.3 years) groups (P < 0.05). There were no significant differences for parity or gestational age at amniocentesis among the groups. There were significant differences for birth age, birth weight, neonatal height, and placental weight among the groups (P < 0.05). HGF concentrations in SGA, AGA and LGA groups were 16.9 +/- 6.6, 16.7 +/- 9.0 and 20.2 +/- 14.8 ng/ml respectively (not significant). There was no correlation between amniotic fluid HGF concentrations and birth weight, height or placental weight. There were also no significant differences for amniotic fluid IGF-I concentrations among the three groups. These results suggest that differences in HGF concentrations in the early second-trimester amniotic fluid do not predict fetal growth at birth. Further study is needed to clarify the role of high HGF concentrations in early second-trimester amniotic fluid during pregnancy.     

胰岛素样生长因子-Ⅰ,脑钠尿肽与心功能分级关系

目的研究心力衰竭患者血浆胰岛素样生长因子-Ⅰ(IGF-Ⅰ)、脑钠尿肽(BNP)水平及其与心功能(NYHA)分级、心脏超声特征之间的关系.方法心力衰竭患者78例,健康对照组18例.使用美国博适-Triage干式快速定量心力衰竭/心肌梗死诊断仪定量快速(15 min)检测全血中BNP含量.用ELISA法检测血清中IGF-Ⅰ水平.并测量左心室收缩末期内径(LVESd)、左心室舒张末期内径(LVEDd)、左室后壁厚度(LVPWT)及左心室射血分数(LVEF).结果对照组、心功能Ⅰ,Ⅱ,Ⅲ,Ⅳ级组BNP值分别为41.3±11.4,156.3±15.1,338.4±23.4,596.4±33.2,972.4±25.4 ng/L,随着心功能分级加重,BNP呈上升趋势,呈正相关.LVEF分别为0.65±0.09,0.62±0.09,0.60±0.08,0.58±0.11,0.35±0.10,与BNP值呈负相关(r=-0.90,P＜0.05).IGF-Ⅰ值分别为166.7±62.5,158.2±55.3,203.5±63.7,240.7±67.3,107.8±66.4μg/L.心功能Ⅱ级与Ⅰ级,Ⅲ级比较,差异有显著性(P＜0.05);而心功能Ⅳ级患者的IGF-Ⅰ水平降低,差异非常显著(P＜0.01).相关性分析显示IGF-Ⅰ值与LVP-WT呈正相关(r=0.75,P＜0.05).结论左室功能不全的患者BNP值升高并与NYHA分级相关,可作为诊断心力衰竭的指标,心功能Ⅱ,Ⅲ级者IGF-Ⅰ水平明显上升,但Ⅳ级者明显降低,如结合BNP浓度可对心力衰竭的预后作出评价.IGF-Ⅰ水平与左室后壁厚度呈正相关,在心功能Ⅳ级组IGF-Ⅰ水平、室壁厚度及EF值均明显降低,提示IGF-Ⅰ水平可能与心室重构有关.     

The hinge region in androgen receptor control

The region between the DNA-binding domain and the ligand-binding domain of nuclear receptors is termed the hinge region. Although this flexible linker is poorly conserved, diverse functions have been ascribed to it. For the androgen receptor (AR), the hinge region and in particular the (629)RKLKKL(634) motif, plays a central role in controlling AR activity, not only because it acts as the main part of the nuclear translocation signal, but also because it regulates the transactivation potential and intranuclear mobility of the receptor. It is also a target site for acetylation, ubiquitylation and methylation. The interplay between these different modifications as well as the phosphorylation at serine 650 will be discussed here. The hinge also has an important function in AR binding to classical versus selective androgen response elements. In addition, the number of coactivators/corepressors that might act via interaction with the hinge region is still growing. The importance of the hinge region is further illustrated by the different somatic mutations described in patients with androgen insensitivity syndrome and prostate cancer. In conclusion, the hinge region serves as an integrator for signals coming from different pathways that provide feedback to the control of AR activity.     

Resolving the growth-promoting and metabolic effects of growth hormone: Differential regulation of GH-IGF-I system components

Growth hormone regulates numerous processes in vertebrates including growth promotion and lipid mobilization. During periods of food deprivation, growth is arrested yet lipid depletion is promoted. In this study, we used rainbow trout on different nutritional regimens to examine the regulation of growth hormone (GH)-insulin-like growth factor-I (IGF-I) system elements in order to resolve the growth-promoting and lipid catabolic actions of GH. Fish fasted for 2 or 6 weeks displayed significantly reduced growth compared to their fed counterparts despite elevated plasma GH, while refeeding for 2 weeks following 4 weeks of fasting partially restored growth and lowered plasma GH. Fish fasted for 6 weeks also exhausted their mesenteric adipose tissue reserves. Sensitivity to GH in the liver was reduced in fasting fish as evidenced by reduced expression of GH receptor type 1 (GHR 1) and GHR 2 mRNAs and by reduced (125)I-GH binding capacity. Expression of GHR 1 and GHR 2 mRNAs also was reduced in the gill of fasted fish. In adipose tissue, however, sensitivity to GH, as indicated by GHR 1 expression and by (125)I-GH binding capacity, increased after 6 weeks of fasting in concert with the observed lipid depletion. Fasting-associated growth retardation was accompanied by reduced expression of total IGF-I mRNA in the liver, adipose and gill, and by reduced plasma levels of IGF-I. Sensitivity to IGF-I was reduced in the gill of fasted fish as indicated by reduced expression of type 1 IGF-I receptor (IGFR 1A and IGFR 1B) mRNAs. By contrast, fasting did not affect expression of IGFR 1 mRNAs or (125)I-IGF-I binding in skeletal muscle and increased expression of IGFR 1 mRNAs and (125)I-IGF-I binding in cardiac muscle. These results indicate that nutritional state differentially regulates GH-IGF-I system components in a tissue-specific manner and that such alterations disable the growth-promoting actions of GH and promote the lipid-mobilizing actions of the hormone.     

Therapeutic action of ghrelin in a mouse model of colitis

BACKGROUND & AIMS: Ghrelin is a novel growth hormone-releasing peptide with potential endogenous anti-inflammatory activities ameliorating some pathologic inflammatory conditions. Crohn's disease is a chronic debilitating disease characterized by severe T helper cell (Th)1-driven inflammation of the colon. The aim of this study was to investigate the therapeutic effect of ghrelin in a murine model of colitis. METHODS: We examined the anti-inflammatory action of ghrelin in the colitis induced by intracolonic administration of trinitrobenzene sulfonic acid. Diverse clinical signs of the disease were evaluated, including weight loss, diarrhea, colitis, and histopathology. We also investigated the mechanisms involved in the potential therapeutic effect of ghrelin, such as inflammatory cytokines and chemokines, Th1-type response, and regulatory factors. RESULTS: Ghrelin ameliorated significantly the clinical and histopathologic severity of the trinitrobenzene sulfonic acid-induced colitis; abrogating body weight loss, diarrhea, and inflammation; and increasing survival. The therapeutic effect was associated with down-regulation of both inflammatory and Th1-driven autoimmune response through the regulation of a wide spectrum of inflammatory mediators. In addition, a partial involvement of interluekin-10/transforming growth factor-beta1-secreting regulatory T cells in this therapeutic effect was demonstrated. Importantly, the ghrelin treatment was therapeutically effective in established colitis and avoided the recurrence of the disease. CONCLUSIONS: Our data demonstrate novel anti-inflammatory actions for ghrelin in the gastrointestinal tract, ie, the capacity to deactivate the intestinal inflammatory response and to restore mucosal immune tolerance at multiple levels. Consequently, ghrelin administration represents a novel possible therapeutic approach for the treatment of Crohn's disease and other Th1-mediated inflammatory diseases, such as rheumatoid arthritis and multiple sclerosis.     

IGF-IR反义寡核苷酸对食管癌EC9706细胞增殖、分化的影响

目的探讨IGF-IR反义寡核苷酸对食管癌EC9706细胞增殖、分化的影响。方法将4组终浓度为20μmol/L的3条封闭IGF-IR不同基因位点的反义寡核苷酸(ASODN1~3)及1条无关寡核酸(N-ODN)分组转染培养的食管癌EC9706细胞,另一组不转染;应用酸解DNA及甲绿-派洛宁染色技术观察各组食管癌EC9706细胞的增殖、分化情况。结果ASODN1~3转染组增殖型细胞分别为:56%、52%和61%,分化型细胞分别为:44%、48%和39%;N-ODN转染组及无转染组增殖型细胞分别为:82%和86%,分化型细胞分别为:18%和14%。对EC9706细胞的增殖、分化的影响,ASODN1~3组间相比差异无统计学意义(P>0.05),但ASODN1~3转染组与N-ODN转染组及无转染组相比,差异均有统计学意义(P<0.05)。结论IGF-IRASODN具有抑制食管癌EC9706细胞增殖,促进其分化效应。     

Endocrine mediators of seasonal growth in gilthead sea bream (Sparus aurata): the growth hormone and somatolactin paradigm

Regulation of somatolactin (SL) and the somatotropic axis was examined year-around at three different stocking times (spring, summer, and autumn) in a Mediterranean fish, the gilthead sea bream (Sparus aurata). The overall timing of plasma growth hormone (GH) increase was similar among trials (late spring-early summer), but the range of variation year-around was different and followed changes in food intake. Total plasma insulin-like growth factor-I primarily followed changes on growth rates, and a close positive correlation between IGF-I and thermal-unit growth coefficient (TGC) was found irrespective of fish stocking time. Thus, the activation of the somatotropic axis preceded always warm growth spurts, whereas the rise of SL in concurrence with low plasma cortisol levels was found at late autumn. This up-regulation of circulating SL titres preceded the winter inhibition of feeding, and it was more severe in big fish (spring and summer stocking times) than in small fish (autumn stocking time), growing with a relative high efficiency during the cold season despite of a severe hypertriglyceridemia and a high hepatosomatic index. These new insights provide good evidence for a different timing of GH and SL increases, and it is likely that the dominant role of SL in energy homeostasis is to be a mediator of the adaptation to fasting after replenishment of body fat stores, whereas GH and IGF-I are perceived as growth-promoting signals in times of food intake and increasing temperature and day-length.     

胰岛素样生长因子-Ⅰ与胰岛素释放试验在糖尿病中的应用

探讨胰岛素样生长因子-Ⅰ(IGF-Ⅰ)与胰岛素(INS)释放试验结合应用对于了解不同类型糖尿病(DM)患者降糖功能受损情况及选择治疗方案、调整用药的作用。对67名正常人和217例DM患者行糖耐量试验(OGTT)、INS释放试验和IGF-Ⅰ测定的结果进行比较分析。空腹血糖与IGF-Ⅰ呈明显负相关,空腹INS与IGF-Ⅰ呈明显正相关。结论：对于人体内INS和IGF-Ⅰ两条降糖途径,INS释放试验能很好地反映前者的状况,IGF-Ⅰ能较好地反映后者的状况,两者结合分析对于DM的诊断和治疗有较大的价值。