Growth hormone insensitivity syndromes: a preliminary report on changes in insulin-like growth factors and their binding proteins during treatment with recombinant insulin-like growth factor I

Serum levels of insulin-like growth factor (IGF) binding proteins (IGFBPs) 1, 2 and 3 were studied by radioimmunoassay in 29 patients with growth hormone (GH) insensitivity syndromes (GHIS) before and during treatment with IGF-I. As in normal subjects, there was a highly significant correlation between IGFs and IGFBP-3 but not between IGFs and the other binding proteins, though IGFBP-3 represented only about one-third of the total IGFBP concentration. In 6 patients with GH deficiency and in 5 patients with GHIS, the pharmacokinetic profile of IGF-I after a single injection was strongly dependent on the IGFBP-3 concentration. A slight but significant increase in IGFBP-3 was observed coincident with the IGF-I peak, whereas IGFBP-2 increased after a delay of about 10 hours. In the patients with GHIS, chronic IGF-I treatment, with twice-daily injections for 6 months, caused a significant steady decline of IGF-II and an increase in IGFBP-2, but had no effect on IGFBP-1 and IGFBP-3 levels. During IGF-I treatment, an inverse relationship between baseline IGF-I and GH levels was observed. The data suggest that total IGF-I and IGF-IL serum levels are determined mainly by IGFBP-3, even in extreme situations such as GHIS, while other IGFBPs are less important. The IGFBP-3 concentration seems to be a major regulator of the pharmacokinetics of exogenous IGF-I, which, in turn, influences IGFBP-3 levels. This effect of IGF-I on IGFBP-3 is not through induction of IGFBP-3 synthesis, but possibly by reduction of IGFBP-3 clearance. Finally, IGF-I administration suppresses GH secretion.     

Absence of hypoglycemia in response to varying doses of recombinant human insulin-like growth factor-I (rhIGF-I) in children and adolescents with low serum concentrations of IGF-I

AIM: To determine whether recombinant human insulin-like growth factor-I (rhIGF-I) administration to children with low IGF-I and relatively low insulin-like growth factor binding protein-3 (IGFBP3) serum concentrations would result in hypoglycemia. METHODS: Eighteen children age 11-19 y with serum levels of IGF-I< -2 SDS and IGFBP3< 0 SDS were randomly assigned to receive rhIGF-I at 80 microg/kg body weight daily (n = 6), 40 microg/kg twice daily (n = 6), or 80 microg/kg twice daily (n = 6). After a 10-d dose escalation and 15 d of treatment at the specified dosage, a 25-h pharmacokinetic/pharmacodynamic profile was obtained, which included 22 blood glucose measurements. Regular meals and snacks were provided. RESULTS: No signs or symptoms of hypoglycemia were noted throughout the study. There were no differences in mean blood glucose concentrations among the three dosage groups. The lowest glucose value recorded, 3.44 mmol/l, was 15 min after a morning injection of 80 microg/kg IGF-I, and promptly rose. Although subjects were selected on the basis of low concentrations of IGF-I to represent proposed candidates for rhIGF-I therapy, the mean and range of SDS for height were not different from those of previously studied normal Ecuadorian controls. CONCLUSION: In normal individuals with low serum concentrations of IGF-I and relatively low concentrations of IGFBP3, the administration of therapeutic doses of rhIGF-I, while maintaining reasonable food intake, does not result in hypoglycemia.     

Effects of insulin-like growth factor I treatment on the molecular distribution of insulin-like growth factors among different binding proteins

The molecular distribution of insulin-like growth factor I (IGF-I) and IGF-II among the IGF binding proteins (IGFBPs) was studied before and during IGF-I therapy in Ecuadorean adults with growth hormone receptor deficiency (GHRD). Of the total circulating IGF-I and IGF-II, 70% was carried by the 150 kDa complex in normal subjects, while in patients with GHRD, 50% of serum IGF-I, but only 30–35% of serum IGF-II, was measured within the 150 kDa IGFBP-3 region. Administration of IGF-I altered the concentration of IGF-I and IGF-II, although the percentage of total IGF measured within each IGFBP region was not affected, as the increase in IGF-I and the decrease in IGF-II were proportional. Similarly, serum concentrations of IGFBP-3 and the acid-labile subunit, measured by radioimmunoassay, were unaltered. Thus, administration of IGF-I to patients with GHRD was unable to correct the aberrant distribution of IGFs among the IGFBPs.     

胰岛素样生长因子-1受体基因变异与矮身材的研究进展

胰岛素样生长因子-1受体(IGF-1 R)是下丘脑-垂体-生长激素轴IGF信号通路的受体级联效应分子.近年来,国外IGF-1R基因突变矮身材报道逐年增多,现将IGF-1R基因缺陷与矮身材的研究进展总结如下,以期引起临床医师的重视.     

Heart rate increases in patients with growth hormone receptor deficiency treated with insulin-like growth factor I

Cardiac function was measured in 16 prepubertal Ecuadorean patients with growth hormone receptor deficiency given insulin-like growth factor I (IGF-I) during part of a clinical trial. The IGF-I was given subcutaneously twice daily at a dose of 40 μg/kg on days 1 and 2, 80 μg/kg on days 3 and 4, and 120 μg/kg thereafter. Heart rate was determined at baseline (pretreatment) and on days 1–7 by repeated palpation of the radial artery and at baseline and on days 2, 4 and 7 by continuous portable Holter monitoring. Heart rate measured by both methods rose progressively with increasing doses of IGF-I. The mean palpated pulse exceeded baseline on each treatment day and was significantly higher on day 5 than day 4 and significantly higher on day 3 than day 2. The mean Holter heart rate was significantly higher on day 4 than on day 2 and significantly higher on day 2 than at baseline. Non-significant glucose and electrolyte changes did not appear to be associated with the cardiac events.     

特发性矮小患儿胰岛素样生长因子受体基因单核苷酸多态性研究

目的：探讨胰岛素样生长因子-I受体（IGF-IR）基因单核苷酸多态性（SNP）与特发性矮小（ISS）的发病危险的相关性。方法：2008~2011年确诊为ISS患儿804例,正常对照组575例,用Snapshot法检测两组 IGF-IR基因相关位点SNP。结果：两组rs1976667基因型分布频率差异无统计学意义（P>0.05）;rs1976667 A等位基因分布频率较正常对照组高,差异有统计学意义（P<0.01)。结论：IGF-IR基因rs1976667位点等位基因A是ISS发病的危险因素。     

Improvement of diagnostic criteria in growth hormone insensitivity syndrome: solutions and pitfalls

A survey to identify children and adolescents with primary growth hormone insensitivity syndrome (GHIS) yielded 38 patients who were positively identified using a scoring system that included five criteria: height, basal growth hormone (GH), GH binding protein, basal insulin-like growth factor 1 (1GF-I) and the increase of IGF-I after 4 days of GH administration (IGF generation test). Because of an overlap of the accepted and excluded groups with respect to points scored, an attempt was made to improve the scoring system. The new criteria were: height below –3 SDS, basal GH 4 mU/I or above, GH binding below 10%, basal IGF-I and basal IGF binding protein-3 (IGFBP-3) below the 0.1 centile for age, an increase of IGF-I in the IGF generation test less than 15 μg/1, and the increase of IGFBP-3 less than 0.4 mg/1. With this scoring system, a clear separation between the accepted and the excluded groups was obtained. IGFBP-3 was included to give the GH-dependent parameters of the IGF system more weight and because the accuracy of IGFBP-3 in the IGF generation tests was greater than the accuracy of IGF-I, when the group of patients with GHIS was compared with a group of patients with GH deficiency. Unexpectedly, the IGF generation test was unable to segregate both cohorts completely. In the GHIS-positive group, a significant correlation was found between basal IGF-I or IGFBP-3 levels corrected for age (SDS) and height SDS ( r = 0.49, p < 0.002 and r = 0.61, p < 0.0001, respectively). There was also a significant correlation between the changes of IGF-I or IGFBP-3 in the IGF generation test and height SDS. That is, the patients with a slight response to GH were those with the least growth retardation, suggesting the existence of partial GH insensitivity.     

胰岛素样生长因子-1生成试验在身材矮小诊治中的应用

身材矮小在儿童内分泌疾病中占较大比例,其病因具有复杂性和交叉性,是儿童生理及心理问题的危险因素之一,需正确诊断并及时治疗。胰岛素样生长因子-1生成试验通过重组人生长激素刺激外周靶细胞分泌胰岛素样生长因子-1,根据胰岛素样生长因子-1的反应情况以评价重组人生长激素的刺激效应,从而进一步诊断身材矮小类型,及时评估重组人生长激素治疗疗效,实现个性化治疗。     

特发性矮小患儿生长激素受体基因Ex3多态性与重组人生长激素疗效分析

目的：观察生长激素受体（GHR）基因Ex3多态性与重组人生长激素（rhGH）治疗青春期前特发性矮小（ISS）疗效间的相关性。方法：青春期前ISS患儿30例,均采用rhGH［0.116±0.02 IU/(kg/d)］治疗;其外周血白细胞中抽提基因组DNA,采用多重PCR扩增GHR基因Ex3区域。对不同基因型患儿治疗后生长速率（GV）、年龄对应身高标准差积分（HtSDSCA）及骨龄对应身高标准差积分（HtSDSBA）、预测终身高进行比较。结果：rhGH治疗半年后d3/d3基因型组GV较fl/fl基因型组明显增加［（6.3±1.6）cm/年 vs （3.4±0.5）cm/年,P<0.05］。结论：ISS患儿GHR Ex3基因型与rhGH促生长疗效存在一定关联,d3/d3等位基因型患儿用rhGH治疗后生长速率明显优于fl/fl等位基因型。［中国当代儿科杂志,2010,12（9）：730-733］     

Three-year data from a comparative study with recombinant human growth hormone in the treatment of short stature in young children with intrauterine growth retardation

Growth acceleration and bone maturation were studied for 3 y in 69 children with severe short stature and a history of intrauterine growth retardation (IUGR), to determine the effect of treatment with recombinant human growth hormone (r-hGH). The patients were enrolled in an open, multicentre trial and were randomly allocated to either the treated group (Group 1) or the control group (Group 2). The children in Group 1 were treated daily with 0.2 IU/kg/body weight (0.067 mg/kg) s.c, during 3 y and the children in Group 2 started the study with a 1-y observation period followed by a 3-y treatment period. At birth, their mean weight standard deviation score (SDS) was -2.5 and their mean length SDS -3.5. At baseline, the patients were prepubertal, non-GHdeficient, with no known dysmorphic features. Mean age was 4.5 y, bone age was 3.3 y, height SDS was -3.4, height velocity (HV) SDS was -1.6, and body mass index SDS was -1.4. After 1 y of treatment, linear HV in Group 1 increased in comparison with the pre-treatment period (from 5.7 ± 2.0 to 10.1 ± 1.7cm/y; p < 0:001)and with the firstyear of observation in Group2( p < 0:001). Increased HV was sustained during the second and third year of treatment and was significantly higher than at baseline. A similar growth pattern was seen during the 3y of GH treatment in Group 2. Mean height SDS for chronological age increased by 2.0 ± 0.7 in the two groups after 3 y of treatment. HV after 1 y of treatment was negatively correlated with growth velocity at baseline. Bone age remained retarded but increased with a mean of almost 4 y after 3y of treatment in both groups. Even at a dose that is three times the replacement dose treatment with r-hGH was well tolerated. From these results, we conclude that r-hGH treatment over 3 y can induce sustained catch-up growth in young children with severe short stature and a history of IUGR. Long-term studies are needed to assess ultimate effects on final height.     

Short stature and growth hormone

Normal growth and development is a prime concern during childhood. Accurate assessment is essential for differentiating between normal and abnormal growth. Increased accessibility to growth hormone has equipped the pediatrician and pediatric endocrinologist to treat and improve growth in many clinical scenarios. At the same time, there is added responsibility to use this tool judiciously. This review summarizes the basics of proper growth assessment, differentiation of normal and abnormal growth causes of and works up of short stature, and delineation of indications for growth hormone treatment.     

Once versus twice daily injections of growth hormone in children with idiopathic short stature

The aim of this study was to compare the growth response of 22 short pre-pubertal children without growth hormone deficiency, treated with a single daily growth hormone injection (group A), to the growth response of 27 similar children, treated with the same daily dose divided into 2 subcutaneous injections per day (group B), for 1 y, in a randomized study. GH treatment significantly promoted growth parameters, height standard deviation score and height velocity standard deviation score in both groups. Serum insulin-like growth factor I was also increased. There were no significant differences in growth response, serum IGF-I levels, or the advance in bone age between the two study groups after 1 y of GH therapy. We conclude that twice daily s.c. growth hormone injections provide no advantages over once daily injection of the same dose in promoting the linear growth of short children without growth hormone deficiency.     

Effects of Short-Term Growth Hormone Therapy in Short Children without Growth Hormone Deficiency

ABSTRACT. Evaluation of 24-hour endogenous growth hormone (GH) secretion was carried out in 62 children, aged 7-16 years, who did not have classic GH deficiency (GHD). The mean 24-hour GH concentration, determined at 20-minute intervals over 24 hours, was variable, ranging from 1.28 to 11.39 μg/l with a mean of 4.95 ± 2.55 μl (± SD). There was a positive correlation between mean 24-hour GH concentration and plasma insulin-like growth factor I (IGF-I) values ( r = 0.54; p < 0.01). Recombinant human GH, 0.1 IU/kg/day was administered to 30 of the 62 children for 6 months followed by 6 months'observation without treatment. Thereafter, GH was administered at the same dose for a further 6 months to 16 children. The mean height velocities before, during, and after the first treatment period were 4.3 ± 0.9, 7.3 ± 1.9 and 4.9 ± 2.0 cm/year (mean ± SD), respectively. The height velocity during treatment was greater than pre- and post-treatment values ( p < 0.001). The height velocity Increased again during the second treatment period to a mean of 8.5 ± 2.0 cm/year ( p < 0.001). Nine other children were treated continuously in a similar manner for 1 year and their height velocity increased significantly from 4.1 ± 1.4 to 6.0 ± 1.9 cm/year ( p < 0.001). According to our criteria, 29 of the 39 children (74.4%) who were treated for 6-12 months showed a GH-dependent height increase during therapy. There were no differences between the children who responded to GH treatment and those who did not in terms of Chronological age, bone age, plasma IGF-I level, maximal GH level to insulin-induced hypoglycaemia, or mean 24-hour plasma GH concentration. These data indicate that some short children without GHD respond to GH treatment with an increased height velocity. Further investigations are required to determine the effect of GH on final height.     

基因重组生长激素治疗青春期前特发性矮小疗效观察

目的探讨基因重组人生长激素（rhGH）对青春期前特发性矮小（ISS）的疗效。方法观察27例青春期前特发性矮小患儿,平均年龄（8.9±2.0）岁,身高（118.0±10.6）cm。治疗组13例,男10例,女3例,均接受基因重组人生长激素治疗,剂量（0.12±0.01）IU/kg,睡前皮下注射,疗程6个月至1年;对照组14例,男6例,女8例。结果治疗组患儿生长速率（GV）由治疗前（4.28±0.86）cm/a提高到（9.38±1.77）cm/a,P〈0.01;年龄身高标准差积分（HtSDSCA）由-2.28±0.48增至-1.72±0.62（P〈0.01）;骨龄身高标准差积分（HtS-DSBA）由-0.24±1.02增至0.27±0.99（P〈0.05）;与对照组比较,GV、HtSDS（CA）和HtSDS（BA）差异均有统计学意义（P均〈0.05）;两组△BA/△CA比较差异无统计学意义（P均〉0.05）。结论GH治疗能改善ISS儿童的GV及HtSDS（CA）、HtSDS（BA）,而骨龄（BA）加速不明显,疗效肯定。     

生长激素受体基因异常及多态性与特发性矮小的关系研究进展

随着促生长激素释放激素-生长激素-胰岛素样生长因子(GHRH-GH-IGF-1)轴和基因学研究的深入,生长激素受体基因(GHR基因)的突变及其核苷酸多态性与特发性矮小(ISS)的关系逐渐明了.GHR基因异常多发生在生长激素受体(GHR)蛋白的胞外区,可引起细胞内信号转导障碍,导致GHR蛋白功能及表达部分缺失,生长激素不能完全发挥作用或部分不敏感,从而可能发生ISS; GHR基因单核苷酸多态性(SNP),尤其是外显子Ex3多态性与ISS易感性有关.此外,GHR基因异常及SNP与ISS中IGF-1、生长激素结合蛋白血清水平及重组人生长激素治疗效果密切相关.深入研究ISS中GHR候选基因的筛查、蛋白功能表达及SNP分析,有利于提高ISS的遗传诊断水平,对明确ISS的病因及指导临床治疗具有重要意义.     

Preliminary validation of a prediction model for the short-term growth response to growth hormone therapy in children with idiopathic short stature

A discriminant scoring system, using multivariate analysis, has been developed for pretreatment prediction of responsiveness to a 6-month trial of growth hormone (GH) treatment in short children with subnormal growth velocity, but without GH deficiency. Inclusion criteria included a birth weight above 2.5 kg, height below the 3rd centile for chronological age, height velocity below the 25th centile for bone age, no signs of puberty, a maximal GH response to pharmacological stimulation of above 10 μg/l and treatment with GH at a dose of 12–16 IU/m²/week. Children with an increase in height velocity greater than 2.5 cm/year after therapy were considered to be responders. Pretreatment clinical data from 67 patients were employed in a discriminant analysis in order to establish the model. The scoring system developed was as follows: score = -0.4 + 0.92X₁– 0.87X₂, where X₁ is the height velocity SD score (SDS) for chronological age, and X₂ is the bone age SDS for chronological age. This model had a specificity of 96.3% and a sensitivity of 92.5% in predicting the responsiveness to GH. The model has subsequently been applied to a group of 14 patients in order to establish its validity; in this group its sensitivity was 83.3% and its specificity 100%. These preliminary data suggest that the model can be used as a guideline for selecting short, slowly growing, non-GH-deficient children who will respond to short-term GH therapy.     

重组人生长激素治疗不同生长激素分泌状态青春前期矮身材患儿近期疗预测模型的建立和验证

目的 建立重组人生长激素(rhGH)治疗生长激素不同分泌状态青春前期矮身材患儿近期(1年)疗效的预测模型,并进行初步验证.方法回顾性分析62例生长激素不同分泌状态的青春前期矮身材患儿[模型组,分为全模型组(模型组全部病例)和生长激素缺乏症模型组(模型组中生长激素缺乏症的病例)]经rhGH治疗1年后的追赶性生长指标:生长速度(HV)和身高Z分增值(ΔHtSDS).根据单因素相关分析的结果,通过多元回归的方法,分别建立对HV和ΔHtSDS的2个预测方程(Model-GHD和Model-total).前瞻性分析另14例(验证组),将资料代入前述方程进行验证.结果单因素相关分析显示,与HV和ΔHtSDS显著(负)相关的是同一组影响因素.所得4个预测方程,R2在0.244～0.519,P值均＜0.05.HV的2个预测方程和对生长激素缺乏症患儿1ΔHtSDS的预测方程(实测值和预测值呈显著正相关,r在0.753～0.996;配对t检验示两者差异无统计学意义).结论预测模型建立成功,有助于预测不同生长激素分泌状态青春期矮身材患儿的生长激素的近期疗效.     

Quality of life of young adults with idiopathic short stature: effect of growth hormone treatment

The aim of the study was to evaluate whether treatment with recombinant human growth hormone (rhGH) affects the quality of life of young adults who were diagnosed as idiopathic short stature (ISS) during childhood, and whether their quality of life and aspects of the personality are different from normal. Experiences and expectations concerning rhGH treatment of the subjects and their parents were also investigated. Eighty-nine subjects were included into the study: 24 subjects (16M, 8F) were treated with rhGH from childhood, whereas 65 subjects (40M, 25F) were never treated. At the time of the interview all subjects had attained final height [mean (SD) -2.3 (0.9) SDS for Dutch references], and the age of the treated subjects was 20.5 (1.0)y, and 25.7 (3.5)y of the control subjects (p < 0:001). The level of education was similar, but the treated subjects had less often a partner compared to the control subjects (adjusted for age and gender, p < 0:001). The Nottingham Health Profile and Short Form 36 Health Survey showed no difference in general health state between treated and control subjects, and the healthy Dutch age-specific references (norm group). Although 74% of the subjects reported one or more negative events related to their height, and 61% would like to be taller, only 22% and 11% were willing to trade-off at Time Trade-Off and Standard Gamble, respectively. The personality of the subjects, which was measured by the Minnesota Multiphasic Personality Inventory, was not different from the norm group. The satisfaction with the rhGH treatment was high, as it had caused 12 (8) cm and 13 (7) cm gain in final height according to the subjects and parents, respectively. Based on initial predicted adult height (Bayley & Pinneau), this gain was only 3.3(5.6) cm. We concluded that although the treated subjects had a partner less often when compared to the control subjects, the quality of life of subjects with ISS at adult age is normal and appears not to be affected by rhGH therapy, The treated subjects were very satisfied with the treatment, probably by overestimation of the final height gain.