Leptin, insulin-like growth factor (IGF)-I and IGF binding protein-3 levels in children with constitutional delay of growth

This study was planned in order to investigate the role of insulin-like growth factor-I (IGF-I), IGF binding protein-3 (IGFBP-3) and leptin, the product of the ob gene synthesized by fat tissue cells, in constitutional delay of growth and puberty (CDGP) which is the most frequent cause of short stature in children. This study was conducted on 80 children with CDGP aged 6-15 years, and 60 healthy children served as controls. Serum IGF-I, IGFBP-3, insulin and plasma leptin levels were measured by immunoradiometric assay. Mean IGF-I and leptin levels were significantly lower in the CDGP group compared with the controls, but the mean IGFBP-3 level was not different in the two groups. Mean leptin levels were 3.72 +/- 2.29 in CDGP and 4.68 +/- 3.08 in the control group (p <0.05). There was a statistically significant relationship between leptin levels and height, weight, and body mass index. Leptin levels were also correlated with chronological age, bone age and height age. When evaluated according to pubertal status, a significant difference was found in IGF-I, leptin and IGFBP-3 levels between prepubertal and pubertal groups. Leptin levels were significantly different in the prepubertal CDGP group compared with controls but in the pubertal CDGP group only IGF-I levels were significantly different from controls. As the weight of children with CDGP was lower than in the control group, it is postulated that the reason for short stature and pubertal delay may be this decrease in weight which is also the cause of low levels of leptin and IGF-I.     

The relationship between ovarian structure and serum insulin, insulin-like growth factor-I (IGF-I) and its binding protein (IGFBP-1 and IGFBP-3) levels in premature pubarche

The aim of this study was to determine serum insulin, insulin-like growth factor-I (IGF-I) and its binding proteins (IGFBP-1 and IGFBP-3) levels and their relationship with androgen levels and ovarian structure in 23 girls with premature pubarche (PP). Fasting levels of testosterone, dehydroepiandrosterone (DHEA) and its sulfate (DHEAS), androstenedione (delta4A), sex hormone binding globulin (SHBG), glucose (G), insulin (I), IGF-I, IGFBP-1, IGFBP-3 were measured. Androgens or steroid hormone levels > 3 SD of normal postpubertal levels were considered as an exaggerated response to the ACTH test. The fasting I to G ratio (FIGR) was calculated and FIGR > 22 was suggestive of insulin resistance (IR). A pelvic ultrasound (US) was carried out and the ovarian structure was divided into five classes (c): c1--homogeneous, c2--microcystic, c3--multicystic, c4--polycystic and c5--follicular. The girls with PP were divided into two groups according to the main ovarian classes observed: PPc1 (n = 6) and PPc2 (n = 15). The FIGR showed IR in 44% of patients. The androgens, SHBG, G, I, FIGR, IGF-I and IGFBP-1 levels were similar among the groups (PPc1 vs PPc2). An exaggerated response to ACTH was more common and IGFBP-3 levels were higher in the PPc2 than in the PPc1 group (p = 0.04). Regression analysis revealed that I was correlated with DHEAS (r = -0.43, p = 0.04) and IGFBP-1 (r = -0.51, p = 0.01); IGF-I was correlated with DHEA (r = -0.42, p = 0.05), delta4A (r = -0.47, p = 0.02), SHBG (r = -0.43, p = 0.04), IGFBP-1 (r = -0.61, p = 0.002) and IGFBP-3 (r = 0.56, p = 0.005); IGFBP-1 was correlated with SHBG (r = 0.56, p = 0.005). These findings suggest that there might be interactions between the insulin-IGF-I-IGFBPs system and hyperandrogenism. However, the possible causal role of adrenal androgen hypersecretion on the insulin-IGF-I-IGFBPs axis and ovarian structure in girls with PP remains to be established. Since studies reveal that IGFBP-3 levels could be a negative predictor for insulin sensitivity throughout puberty, we hypothesize that girls with PP and microcystic ovaries are at risk of developing IR in the course of normal puberty.     

Evaluation of insulin-like growth factor (IGF)-I and IGF binding protein-3 generation test in short stature

BACKGROUND: Differentiation between growth hormone deficiency (GHD) and idiopathic short stature (ISS) based on GH tests and basal IGF-I and IGFBP-3 levels may be difficult. The aim of this study was to evaluate the role of pharmacological GH tests, IGF-I and IGFBP-3 generation test and height velocity off-treatment in the evaluation of GHD and ISS. METHODS: Thirty-three (17 M, 16 F) prepubertal short (height SDS < -2) children were divided into two groups: Group 1 (n = 19) with peak GH level <10 tg/l (GHD) and Group 2 (n = 14) GH > or =10 microg/l in two sex steroid primed pharmacological GH tests. Having excluded other diagnoses, Group 2 was regarded as having ISS. The generation test was performed concomitantly (0.1 IU/kg GH s.c. for 4 days) with IGF-I and IGFBP-3 measured on the 4th day in both groups. The patients were followed for a year for height velocity (HV). RESULTS: Group 1 and 2 had comparable height SDS (-2.3 +/- 0.4 and -2.3 +/- 0.3) at comparable ages (7.8 +/- 2.8 and 7.0 +/- 2.7 yr). Although the deltaIGF-I response was low (<2.0 nmol/l 115 ng/ ml]) in seven (37%) children in the GHD group, all GHD patients with low height velocity had adequate (> or =14 nmol/I [400 ng/ml]) deltaIGFBP-3 response. deltaIGFBP-3 in the generation test showed a negative correlation with HV (p = 0.021, r = -0.570) and also with basal IGFBP-3 (p <0.001, r = -0.743) in the GHD group. In the ISS group, deltaIGF-I and deltaIGFBP-3 responses were low in 31% and 7%, respectively, and the correlation between basal IGF-I, IGFBP-3 and HV and between delta values in the generation test were significantly positive, pointing to a difference in the growth response of these children. CONCLUSION: In the GHD group, based on pharmacological tests, an adequate deltaIGFBP-3 response in the generation test predicts poor height velocity at follow up and thus strengthens the diagnosis of true GHD.     

Serum insulin-like growth factor (IGF)-I and IGF-binding protein-3 in girls with premature thelarche

Premature thelarche (PT) is characterised by precocious breast development without any other sign of puberty, normal height velocity (HV) and normal bone maturation, while girls with central precocious puberty (CPP) show increased HV, bone maturation and increased serum IGF-I and IGFBP-3 levels. This prompted us to study serum IGF-I and IGFBP-3 concentrations in girls with PT. Thirty-nine girls with premature breast development were studied and classified as PT or CPP according to clinical and laboratory evaluation. Normal prepubertal and pubertal girls were studied as controls. Serum IGF-I and IGFBP-3 were determined in all girls by IRMA. IGF-I levels in PT (155 +/- 61 microg/l) were lower than in CPP (337 +/- 149 microg/l) or late-pubertal controls (355 +/- 84 microg/l) and similar to those found in prepubertal (113 +/- 72 microg/l) and early-pubertal (222 +/- 81 microg/l) girls. Considering the SDS of IGF-I for chronological age (CA), the values observed in PT were in an intermediate position between CPP and prepubertal controls and statistically similar to those observed in CPP and prepubertal girls. IGFBP-3 levels in PT (2.1 +/- 0.5 mg/l) were similar to those found in CPP (2.5 +/- 0.8 mg/l), but only the latter were higher than in prepubertal girls (1.9 +/- 0.9 mg/l). IGF-I/IGFBP-3 molar ratios in PT were in an intermediate position between CPP and prepubertal controls. In conclusion, IGF-I and IGF-I/IGFBP-3 values in PT are intermediate between those observed in prepubertal children and in CPP, suggesting that PT could be a very early stage of puberty with slight but real changes in the GH-IGF axis.     

Cerebrospinal fluid insulin-like growth factor (IGF-1) and insulin-like growth factor binding protein (IGFBP-2) in children with acute lymphoblastic leukemia

BACKGROUND: Insulin-like growth factor-1 (IGF-1) has specific effects on axonal growth and myelination, low CSF IGF-1 levels being found in some severe neurologic diseases. We studied the levels of CSF IGF-1 and IGF binding protein-2 (IGFBP-2) in children with ALL to find out whether these levels correlated with any of the neurological deficits observed. METHODS: IGF-1 and IGFBP-2 levels were prospectively measured by radioimmunoassay in the CSF of 14 children with ALL throughout the ALL chemotherapy. These were compared with the levels of 16 control subjects and of patient groups with severe neurological diseases. RESULTS: During induction, the children with ALL had subnormal CSF IGF-1 levels which improved after 2 months. In seven individuals, two with severe vincristine polyneuropathy, the subnormal levels persisted throughout the chemotherapy. CONCLUSIONS: Our findings suggest impairment of the IGF-1 trophic system during induction by a mechanism so far unknown. Correlation with disturbed neuronal function could not be statistically proven.     

Serum zinc, insulin-like growth factor-I and insulin-like growth factor binding protein-3 levels in children with type 1 diabetes mellitus

BACKGROUND: Growth is impaired during the course of diabetes mellitus (DM). Derangement of the growth hormone/insulin-like growth factor (IGF) axis, insulinopenia and zinc deficiency are the possible causative factors of this impairment. Zn supplementation is proven to attenuate hyperglycemia in mice but its use to ameliorate impaired height is still a matter of discussion. OBJECTIVE: To investigate serum Zn, IGF-I and IGF binding protein-3 (IGFBP-3) levels and to emphasize the potential beneficial effects of Zn supplementation for the prevention of growth failure in children with type 1 DM (DM1). Patients and Methods: Twenty-eight patients with DM1 and 15 control children were included in the study. Zn levels were measured by flame atomic absorption spectrophotometry; IGF-I and IGFBP-3 levels were measured by immunoradiometric assay. RESULTS: Mean serum Zn levels were significantly lower in diabetic children taken as a whole and as their pubertal subgroup compared to the controls. Mean serum IGF-I and IGFBP-3 levels were significantly lower in both prepubertal and pubertal diabetic groups compared to those of control groups. CONCLUSION: From the results of our study, it can be hypothesized that serum Zn levels should be closely monitored during the course of DM1 and supplementation may be given to patients, especially at the time of puberty. This hypothesis needs to be confirmed by further studies.     

Low insulin, IGF-I and IGFBP-3 levels in children with Prader-Labhart-Willi syndrome

It is well established that insulin-like growth factor I (IGF-I), insulin-like growth factor binding protein-3 (IGFBP-3) and insulin are low in growth hormone deficiency, but due to their dependence on nutrition, they are elevated in healthy obese children. As the presence of growth hormone deficiency in Prader-Labhart-Willi syndrome (PWS) is still controversial, we studied insulin, IGF-I and IGFBP-3 levels in 19 children with PWS (age range 0.5–14.6 years). Serum concentrations of insulin (SDS: −0.7±0.9, P=0.01) and IGF-I (SDS: −0.7±0.8,P=0.002) were low, but IGFBP-3 (SDS: −0.3±1.2, P=0.2) was normal compared to normal weight age-matched children. Since children with PWS are typically obese, insulin, IGF-I and IGFBP-3 levels should be compared to normal obese children who present increased levels of these hormones. In comparison to data of healthy obese children reported in the literature, not only IGF-I, but also IGFBP-3 levels are low and fasting insulin levels even very low, suggesting a growth hormone deficiency. Received: 19 November 1997 / Accepted in revised form: 2 March 1998     

Maternal and fetal serum insulin-like growth factor-I (IGF-I) IGF binding protein-3 (IGFBP-3), leptin levels and early postnatal growth in infants born asymmetrically small for gestational age

This study was planned to investigate the relationship between birth weight and insulin-like growth factor-I (IGF-I), IGF binding protein-3 (IGFBP-3), and leptin levels in neonates with normal growth (appropriate for gestational age: AGA) and retarded growth (small for gestational age: SGA); and to evaluate these growth factors' effects in early postnatal growth. All newborns were full-term: gestational age 3,841 weeks. Of 50 neonates, 25 were SGA. IGF-I, IGFBP-3 and leptin levels were measured in maternal serum and venous cord blood at birth and at 15 days of life of neonates using specific RIAs. Maternal serum leptin concentrations were significantly higher than cord blood leptin concentrations (p < 0.001). Maternal serum IGF-I, IGFBP-3 and leptin levels did not show correlations with birth weight. In contrast, there were significantly positive correlations between birth weight and venous cord blood IGF-I, IGFBP-3 and leptin levels (p < 0.001). In the SGA group, the newborns with a slow postnatal growth pattern had lower umbilical cord serum IGF-I levels compared with newborns with a normal growth pattern. A similar result was also found in the AGA group. Similar results were not found for serum leptin and IGFBP-3. In conclusion, cord blood IGF-I, IGFBP-3 and leptin levels play an important role in the regulation of fetal and neonatal growth. It is likely that IGF-I has a more important role than the other factors in early postnatal growth.     

儿童急性淋巴细胞白血病血清IGF-1和IGFBP-3表达变化及其意义

目的：探讨急性淋巴细胞白血病（ALL）患儿血清中胰岛素样生长因子-1（IGF-1）、胰岛素样生长因子结合蛋白-3（IGFBP-3）水平的表达变化及其临床意义。 方法：36例ALL患儿分别在治疗前和完全缓解后6个月留取血清, 对照组血清来自30例外科疾病患儿。应用放射免疫法（RIA）测定IGF-1和免疫放射法（IRMA）测定IGFBP-3水平。结果：ALL组治疗前血清IGF-1、IGFBP-3水平分别为19±4 ng/mL和1216±132 ng/mL,低于对照组的IGF-1、IGFBP-3水平（分别为32±3 ng/mL、2104±191 ng/mL）, 差异有统计学意义（P0.05）。结论：ALL患儿血清IGF-1和IGFBP-3水平降低,并随着病情缓解而升高。提示IGF-1和IGFBP-3可能可以作为儿童ALL诊断及疗效判断的有效指标。     

Diagnosis of idiopathic growth hormone deficiency: contributions of data on the acid-labile subunit, insulin-like growth factor (IGF)-I and-II, and IGF binding protein-3

The diagnosis of non-organic growth hormone (GH) deficiency (GHD) remains difficult. OBJECTIVE: To evaluate the value of measuring plasma insulin-like growth factor (IGF)-I and -II, IGF binding protein-3 (IGFBP-3) and acid-labile subunit (ALS) as criteria for diagnosing GHD. PATIENTS: 120 prepubertal patients having at least one of the main auxological criteria defined by the GH Research Society for initiating GH exploration were classified as (1) certain GHD (n = 40), (2) transient GHD (n = 18), (3) idiopathic short stature (n = 27), or (4) extreme short stature (n = 35). RESULTS: All the patients with certain GHD had low (< or = -2 z-score) plasma concentrations of IGF-I and ALS, but only 35.1% had low IGF-II, and 48.6% had low IGFBP-3. All the patients but three (83.3%) with transient GHD had low IGF-I, but only 44.4% had low ALS, and only one had low IGF-II or IGFBP-3. The data for patients with idiopathic and extreme short stature and normal GH peak were similar to each other and to those for patients with transient GHD, except that IGF-I was less frequently low (49.2%, p <0.05). CONCLUSIONS: All the patients with certain GHD had both IGF-I and ALS z-scores < or = -2, unlike those with transient GHD, and idiopathic or extreme short stature. Almost all the patients with short stature and normal GH peak had normal serum IGF-II and IGFBP-3 concentrations.     

宫内发育迟缓与胰岛素样生长因子及其结合蛋白关系研究

为了解脐血中胰岛素样生长因子_I(IGF -I)、胰岛素样生长因子结合蛋白_3(IGFBP_3)的水平变化与胎儿期生长的关系 ,将86例新生儿脐血标本分为宫内发育迟缓 (IUGR ,即小于胎龄儿 )组 (22例 )及适于胎龄儿 (AGA)组 (64例 )两组 ,采用竞争性放射免疫分析法 (RIA)测定IGF_1水平、非竞争性免疫放射分析法 (IRMA)测定IGF BP_3水平。结果显示 ,与AGA组相比 ,IUGR组脐血中IGF_1和IGFBP_3水平显著降低 (P均<0.01) ;IGF_1、IGFBP_3水平均随胎龄及出生体重增加而增加 (P均<0.01) ;IGFBP_3与IGF_1呈正相关 (P<0.01)。提示IUGR与IGF_1及其结合蛋白降低密切相关 ;脐血中IGF_1、IGFBP_3水平与胎龄及出生体重呈正相关     

Clinical utility of insulin-like growth factor-I (IGF-I) and IGF binding protein-3 measurements in paediatric practice

Measurements of serum insulin-like growth factor-I (IGF-I) and its major binding protein, IGFBP-3, are utilised in the routine clinical management of short children. In this review, the value of such measurements in the diagnosis of primary and secondary IGF-I deficiency is presented. The achievement of optimal growth while maintaining IGF-I within the normal range is the goal of GH treatment schedules used in a range of growth disorders, and thus data on IGF-I monitoring during initiation and maintenance phases of GH treatment are discussed. Comment is also made on the relationship between levels of IGF-I and IGFBP-3 in the population with regard to risks for cancer and cardiovascular disease.IGF-I and IGFBP-3 are important parameters to measure as one part of the process of managing short children. It is proposed that improving the clinical value of IGF measurement may involve measurement of specific prohormones and E-peptides, to get closer to the pool of GH dependent IGF-I.     

孤独症谱系障碍儿童的血清胰岛素样生长因子-1和胰岛素样生长因子结合蛋白-3水平研究北大核心CSCD

目的探讨孤独症谱系障碍(autism spectrum disorder,ASD)儿童的血清胰岛素样生长因子-1(insulin-like growth factor-1,IGF-1)和胰岛素样生长因子结合蛋白-3(insulin-like growth factor binding protein-3,IGFBP-3)水平及与孤独症核心症状之间的关系。方法前瞻性选取重庆市妇幼保健院门诊招募的150名2~7岁ASD儿童和165名年龄、性别相匹配的正常健康儿童为研究对象,采用孤独症行为量表和孤独症评定量表评估ASD儿童核心症状,采用化学发光法检测两组儿童血清IGF-1和IGFBP-3水平。结果ASD组儿童血清IGF-1水平低于对照组儿童(P<0.05)。重度ASD儿童血清IGF-1和IGFBP-3水平低于轻-中度ASD儿童(P<0.001),2~3岁ASD儿童血清IGF-1水平低于对照组儿童(P<0.05)。两组男童IGF-1水平均低于女童(P<0.05)。血清IGF-1、IGFBP-3水平与儿童孤独症评定量表总分呈负相关(分别r=-0.32、-0.40,均P<0.001)。结论儿童早期血清IGF-1降低可能与ASD疾病发展相关,血清IGF-1和IGFBP-3水平与ASD儿童核心症状具有一定关联。     

Serum levels of insulin-like growth factor-I,-II and insulin-like growth factor binding proteins-2 and-3 in children with acute lymphoblastic leukaemia

Abstract The insulin-like growth factor (IGF) signaling pathway may be of importance for the proliferation of different tumours (e.g. breast cancer and Wilms tumour). The bioavailability of both IGF-I and IGF-II is regulated by specific IGF-binding proteins (IGFBPs). IGFBP-2 is the predominant binding protein during fetal life, where it is expressed in most tissues. In contrast, postnatally it is mainly released by specific cell types (hepatocytes, astroglia, kidney cells, prostate cells) and a range of tumour cell lines. Furthermore, phytohaemagglutinin stimulated normal lymphoblasts and malignant lymphoblasts express IGFBP-2. In order to investigate the IGF regulatory pathway in leukaemia serum levels of IGF-I, IGF-II, IGFBP-2 and IGFBP-3 were determined in 28 leukaemic children. Whereas serum levels of IGF-I (mean/range: –2.7/–0.1 to –6.7 SDS), IGF-II (–3.6 SDS/–1.3 to –8.7) and IGFBP-3 (–2.0/+2.2 to –7.1 SDS) were significantly decreased comparable to levels in growth hormone deficiency, IGFBP-2 levels (+4.0/–0.45 to +7.4 SDS) were found to be markedly elevated and inversely correlated to IGF-I (r=–0.51,P=0.013). After haematological remission upon chemotherapy all four parameters had normalized in the 16 re-investigated children. Similar findings have been observed in one boy with a relapse including CNS leukaemia.Conclusion This study demonstrates that the proliferation of malignant lymphoblasts (at diagnosis vs treatment) occurs in the presence of decreased serum levels of IGF-I, IGF-II and IGFBP-3 and that diminished production of these peptides may contribute to impaired growth. It further indicates that serum levels of IGFBP-2 may be directly related to the proliferation of lymphoblasts.     

Serum insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 levels in severe iodine deficiency

Iodine deficiency is an important public health problem worldwide. It is well known that it has severe consequences such as brain damage, developmental delay, deficits in hearing and learning and lower intellectual attainment. It also has a negative impact on growth. In this study, we aimed to address this issue and we assessed height standard deviation scores of children living in an area of severe iodine deficiency in comparison to those living in a mild iodine deficiency area. Serum levels of insulin-like growth factor-I (IGF-I), IGF-binding protein-3 (IGFBP-3), thyroxine (T4), and thyroid stimulating hormone (TSH) were also analyzed to investigate the mechanisms by which iodine depletion leads to growth failure. Pubertal children in a severe iodine deficient SID area had lower height standard deviation scores (HSDS), IGF-I and IGFBP-3 levels than those living in mild iodine deficient MID area. Similar findings could not be elucidated in the prepubertal age group. The major determinants of HSDS were age, IGF-I, IGFBP-3 and TSH. IGF-I and IGFBP-3 were negatively correlated with T4. These findings suggest that iodine deficiency has a negative impact on growth, as well as IGF-I and IGFBP-3 levels. This effect seems to be due to the derangements in thyroid hormone economy arising from iodine depletion. The degree of this impact may be related to the duration of iodine depletion or may be dependent on the developmental stage of the organism at the time of iodine depletion.     

Insulin-like growth factor-I (IGF-I) ameliorates and IGF binding protein-1 (IGFBP-1) exacerbates the effects of undernutrition on brain growth during early postnatal life: studies in IGF-I and IGFBP-1 transgenic mice

Insulin-like growth factor-I (IGF-I) plays an important role in the stimulation of postnatal brain growth. In transgenic (Tg) mice, IGF-I overexpression stimulates postnatal brain growth, whereas decreased IGF-I availability caused by ectopic brain expression of IGF binding protein-1 [(IGFBP-1), an inhibitor of IGF-I action] retards postnatal brain growth. Because undernutrition during early postnatal development profoundly retards growth and maturation of the brain in rodents, we sought to determine the influence of IGF-I on undernutrition-induced brain growth retardation. Caloric restriction was imposed on IGF-I Tg mice, IGFBP-1 Tg mice, and their non-Tg littermates by separating half of each litter from their dams during the suckling period, postnatal d 1 to 21. Undernutrition reduced the brain growth of each group of mice, but the growth of undernourished IGF-I Tg mice was comparable to that of well-fed control mice (increased 4.13- and 4.22-fold, respectively) and greater than that of undernourished control mice (increased 3.45-fold), whereas undernourished IGFBP-1 Tg mice exhibited less growth (increased 3.15-fold) than undernourished control mice. When the effects of undernutrition were examined in specific brain regions of each group, the same pattern was observed, and IGF-I was found to be more effective in preserving the growth of the regions with the highest transgene expression (cerebral cortex, hippocampus, and diencephalon). Despite undernutrition, IGF-I transgene expression stimulated overgrowth of these regions as well as that of the posterior medial barrel subfield, a somatosensory area of the cerebral cortex in which IGF-I may be especially important in development. These data indicate that IGF-I can ameliorate the brain growth retardation caused by undernutrition imposed during development, although it is unclear whether IGF-I directly opposes the impact of undernutrition or acts independently of nutritional status. Nonetheless, these findings raise the possibility that the relatively high IGF-I expression during early postnatal life may be responsible for sparing the brain from the full impact of undernutrition during this time in development.     

Serum levels of insulin-like growth factor binding proteins in Ecuadorean children with growth hormone insensitivity

Although insulin-like growth factor binding proteins (IGFBPs) are known to be important modulators of the action of insulin-like growth factors (IGFs), regulation of their production in vivo is not completely understood. Serum concentrations of IGFBP-3, -4 and -5 and acid-labile subunit (ALS) were therefore examined in 20 children with growth hormone (GH) insensitivity before and after 6 months of therapy with recombinant human IGF-I (80 or 120 micrograms/kg twice daily). The IGFBP concentrations in these children were compared with those in 62 GH-deficient children receiving GH therapy for 3 months. Serum levels of IGFBP-3, -4 and -5 and ALS all increased significantly (p < 0.0001) in GH-deficient children in response to GH therapy, whereas no significant increases occurred in the children with GH insensitivity. These findings indicate that GH is responsible for the regulation of serum levels of IGFBP-3, -4 and -5 and ALS, and that IGF-I does not directly regulate the concentrations of these circulating IGFBPs.     

Serum levels of insulin-like growth factor binding proteins in Ecuadorean children with growth hormone insensitivity

Burren CP, Wanek D, Mohan S, Cohen P, Guevara-Aguirre J, Rosenfeld RG. Serum levels of insulin-like growth factor binding proteins in Ecuadorean children with growth hormone insensitivity. Acta Pædiatr 1999; Suppl 428: 185–91. Stockholm. ISSN 0803–5326
Although insulin-like growth factor binding proteins (IGFBPs) are known to be important modulators of the action of insulin-like growth factors (IGFs), regulation of their production in vivo is not completely understood. Serum concentrations of IGFBP-3, -4 and -5 and acid-labile subunit (ALS) were therefore examined in 20 children with growth hormone (GH) insensitivity before and after 6 months of therapy with recombinant human IGF-I (80 or 120 ug/kg twice daily). The IGFBP concentrations in these children were compared with those in 62 GH-deficient children receiving GH therapy for 3 months. Serum levels of IGFBP-3, -4 and -5 and ALS all increased significantly ( p < 0.0001) in GH-deficient children in response to GH therapy, whereas no significant increases occurred in the children with GH insensitivity. These findings indicate that GH is responsible for the regulation of serum levels of IGFBP-3, -4 and -5 and ALS, and that IGF-I does not directly regulate the concentrations of these circulating IGFBPs. □ Growth hormone, growth hormone insensitivity, insulin-like growth factor I, insulin-like growth factor binding protein     

Early Aggressive Parenteral Nutrition Induced High Insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP3) Levels Can Prevent Risk of Retinopathy of Prematurity

Objective

To evaluate early aggressive vs. conservative nutrition and its effect on Retinopathy of Prematurity (ROP) in <32 weeks of gestation neonates.

Methods

A prospective, randomized, clinical study was conducted in NICU with a total of 75 preterm infants. In the intervention group, infants received early aggressive nutrition immediately after birth, in the control group infants were started on conventional parenteral nutrition (PN). Blood samples were obtained for Insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP3) levels before commencement of PN on the first postnatal day, and from week 1 to 6 every week. All the infants were examined for ROP.

Findings

Infants in the early aggressive group had a reduction in the risk of ROP of 5% (2 from 40); the number of infants needed treatment averaged 3.7 (2.7 to 5.2). A total of 11 neonates in the conventional group were detected having ROP (P<0.05). Overall, IGF-I levels were higher in the aggressive PN (APN) vs the conventional PN (CPN). ROP development was higher in the CPN compared to the APN. IGF-1levels were lower in ROP developers compared with non-ROP in the APN group. There was no difference in IGF-I levels in ROP developers versus non-ROP in the CPN group. IGF-1 levels were lower in the CPN group compared with the APN group in the third week in ROP developers. There was a correlation between ROP and IGF-1 levels. Through ROC analysis, IGF-1 was demonstrated as being a sensitive marker for ROP.

Conclusion

IGF-1 levels were higher in the APN group versus the CPN group. This may indicate that IGF-1 levels simply being higher is not enough; rather, that being higher above a cutoff value may prevent ROP.     

How to use insulin-like growth factor 1 (IGF1)

Insulin-like growth factor 1 (IGF1) is produced in the liver and peripheral tissues including the growth plate, in response to growth hormone (GH) and is commonly used as a diagnostic marker of growth hormone deficiency (GHD) and to monitor GH replacement therapy, as recommended by an international GH consensus.1 However, while it is a useful biochemical tool, there are limitations to its use and results should be interpreted with care.