Modulation of growth factors by growth hormone in children with chronic renal failure. The Southwest Pediatric Nephrology Study Group

[Chronic kidney disease and growth failure: Efficacy of growth hormone treatment]

Growth failure is a frequent complication observed in children with chronic kidney disease (CKD) and correlated to increased morbidity and mortality. To achieve a normal growth in children with CKD remains challenging for pediatric nephrologists. Growth failure in the setting of pediatric CKD is multifactorial and related to an impaired sensitivity to growth hormone and to a deficiency of IGF1 (insulin-like growth factor 1). Growth failure management has improved during the last two decades and consists of correcting any nutritional and metabolic abnormalities, of an improvement of dialysis for children on end-stage renal disease, and of an administration of a supraphysiologic dose of recombinant growth hormone to overcome GH insensitivity. This article summarizes the causes, outcomes and assessment tools of growth in children with CKD as well as the management of recombinant growth hormone.

Growth Hormone and Insulin-Like Growth Factor Dysregulation in Pediatric Chronic Kidney Disease

Poor growth is a common finding in children with chronic kidney disease (CKD) that has been associated with poor long-term outcomes. The etiology of poor growth in this population is multifactorial and includes dysregulation of the growth hormone (GH) and insulin-like growth factor (IGF) axis. In this review, we describe the data on GH resistance or insensitivity and inappropriate levels or reduced bioactivity of IGF proposed as contributing factors of growth impairment in children with CKD. Additionally, we describe the theorized negative effect of metabolic acidosis, another frequent finding in pediatric CKD, on the GH/IGF axis and growth. Last, we present the current and potential therapies for the treatment of short stature in pediatric CKD that target the GH/IGF hormonal axis.

Patterns of recombinant growth hormone therapy use and growth responses among children with chronic kidney disease

BACKGROUND

Recombinant growth hormone (rGH) is an efficacious therapy for growth failure in children with chronic kidney disease (CKD). We described rGH use and estimated its relationship with growth and kidney function in the Chronic Kidney Disease in Children (CKiD) cohort.

METHODS

Participants included those with growth failure, prevalent rGH users, and rGH initiators who did not meet growth failure criteria. Among those with growth failure, height z scores and GFR were compared between rGH initiators and non-initiators across 42 months. Inverse probability weights accounted for differences in baseline variables in weighted linear regressions.

RESULTS

Among 148 children with growth failure and no previous rGH therapy, 42 (28%) initiated rGH therapy. Of the initiators, average age was 8.9 years, height z score was 2.50 standard deviations (SDs) (0.6^th percentile), and GFR was 44 ml/min/1.73m². They were compared to 106 children with growth failure who never initiated therapy (8.8 years, -2.33 SDs, and 51 ml/min/1.73m²). At 30 and 42 months after rGH, height increased +0.26 (95%CI: -0.11, +0.62) and +0.35 (95%CI: -0.17, +0.87) SDs, respectively, relative to those who did not initiate rGH. rGH was not associated with GFR.

CONCLUSIONS

Participants with growth failure receiving rGH experienced significant growth, although this was attenuated relative to RCTs, and were more likely to have higher household income and lower GFR. A substantial number of participants, predominantly boys, without diagnosed growth failure received rGH and had the highest achieved height relative to mid-parental height. Since rGH was not associated with accelerated GFR decline, increasing rGH use in this population is warranted.

Long Term Experience with Growth Hormone Treatment in Children with Chronic Renal Failure

After a decade of experience with recombinant human growth hormone (rhGH) in children with chronic renal failure (CRF), the long-term efficacy and safety of the drug is now established. In prepubertal children, partial catch-up growth is achieved during the first three treatment years, followed by sustained percentile-parallel growth. Discontinuation of rhGH treatment results in catch-down growth in 75% of patients. Treatment efficacy is inversely correlated with age and baseline height velocity, and positively influenced by genetic target height and residual renal function. Skeletal maturation is not accelerated, suggesting a true increase in final height potential. Side effects are limited to a stimulation of insulin secretion, which is not associated with changes in glucose tolerance, and occasional cases of benign intracranial hypertension.

In summary, the advent of rhGH has opened a new era in the management of growth failure in CRF. Available evidence suggests that treatment should start in early childhood and early in the course of renal failure, and should be continued at least until renal transplantation. It remains to be seen whether the beneficial effect of rhGH on height observed during the prepubertal period will result in an eventual increase in adult height.

Serum Markers of Low-Turnover Bone Disease in Mexican Children with Chronic Kidney Disease Undergoing Dialysis

Background

The frequency of low-turnover bone disease (LTBD) in patients with chronic kidney disease (CKD) has increased in past years. This change is important because LTBD is associated with bone pain, growth delay, and higher risk for bone fractures and extraosseous calcifications. LTBD is a histological diagnosis. However, serum markers such as parathyroid hormone (PTH) and calcium levels offer a noninvasive alternative for diagnosing these patients.

Objective

To describe the prevalence of LTBD in pediatric patients with renal failure undergoing some form of renal replacement therapy, using serum calcium and intact PTH levels as serum markers.

Methods

In this cross-sectional study, 41 children with CKD undergoing dialysis treatment (31 on continuous ambulatory peritoneal dialysis and 10 on hemodialysis) were included. There were no inclusion restrictions with respect to gender, cause of CKD, or dialysis modality. The children were studied as outpatients. The demographic data, CKD course, time on dialysis, phosphate-binding agents, and calcitriol prescription were registered, as well as weight, height, Z-score for height, linear growth rate, and Z-score for body mass index. Serum calcium, phosphorus, aluminum, PTH, alkaline phosphatase, osteocalcin, glucose, creatinine, urea, cholesterol, and triglycerides were measured.

Results

There were 20 (48.8%) children with both PTH <150 pg/mL and corrected total calcium >10 mg/dL who were classified as having LTBD[(+)]; the remaining 21 (51.2%) children were classified as having no LTBD[(–)]. The LTBD(+) patients were younger (11.2 ± 2.7 vs 13.2 ± 2.4 years, p < 0.01) but they had no differences regarding Z-scores for height. Linear growth in 6 months was less than expected in both groups (-0.15 ± 0.23 cm/month), but the difference between expected and observed growth was higher in the LTBD(+) group (-0.24 ± 0.14 vs –0.07 ± 0.28 cm/mo, p < 0.03). LTBD(+) patients also had lower serum creatinine (8.69± 2.75 vs 11.19 ± 3.17 mg/dL, p < 0.01), higher serum aluminum levels [median (range) 38.4 (9 – 106) vs 28.1 (9 – 62) μg/L, p < 0.05], and lower systolic blood pressure (112.0 ± 10.3 vs 125.0 ±12.9 mmHg, p < 0.015) and diastolic blood pressure (76.0 ± 9.7 vs 84.5 ± 8.2 mmHg, p < 0.017). A significant correlation was found between PTH and alkaline phosphatase ( r = 0.68, p < 0.001), but not between PTH and aluminum.

Conclusion

The LTBD(+) biochemical profile was found in 48.8% of the children and was associated with impaired linear growth. Aluminum contamination, evidenced by higher serum aluminum levels, may have had a pathogenic role in these disorders. Higher systolic and diastolic blood pressure levels may be related to higher serum PTH levels.

Clinical practice recommendations for growth hormone treatment in children with chronic kidney disease

Achieving normal growth is one of the most challenging problems in the management of children with chronic kidney disease (CKD). Treatment with recombinant human growth hormone (GH) promotes longitudinal growth and likely enables children with CKD and short stature to reach normal adult height. Here, members of the European Society for Paediatric Nephrology (ESPN) CKD–Mineral and Bone Disorder (MBD), Dialysis and Transplantation working groups present clinical practice recommendations for the use of GH in children with CKD on dialysis and after renal transplantation. These recommendations have been developed with input from an external advisory group of paediatric endocrinologists, paediatric nephrologists and patient representatives. We recommend that children with stage 3–5 CKD or on dialysis should be candidates for GH therapy if they have persistent growth failure, defined as a height below the third percentile for age and sex and a height velocity below the twenty-fifth percentile, once other potentially treatable risk factors for growth failure have been adequately addressed and provided the child has growth potential. In children who have received a kidney transplant and fulfil the above growth criteria, we recommend initiation of GH therapy 1 year after transplantation if spontaneous catch-up growth does not occur and steroid-free immunosuppression is not a feasible option. GH should be given at dosages of 0.045–0.05 mg/kg per day by daily subcutaneous injections until the patient has reached their final height or until renal transplantation. In addition to providing treatment recommendations, a cost-effectiveness analysis is provided that might help guide decision-making.

This Evidence-Based Guideline developed by members of the European Society for Paediatric Nephrology CKD-MBD, Dialysis and Transplantation working groups presents clinical practice recommendations for the use of growth hormone in children with chronic kidney disease on dialysis and after renal transplantation.

Growth hormone treatment improves final height and nutritional status of children with chronic kidney disease and growth deceleration

PURPOSE

Growth retardation is a common complication of chronic kidney disease (CKD) in children. Treatment with recombinant human growth hormone (rhGH) has been used to help short children with CKD to attain a height more in keeping with their age group, but the scientific evidence regarding the effect of rhGH on final height is scarce.

METHODS

Final heights of children with CKD receiving rhGH treatment (cases) were compared with final heights of a matched cohort of children with CKD that did not receive rhGH therapy (controls).

RESULTS

Sixty-eight rhGH-treated cases (44 boys) were compared with 92 untreated controls (60 boys). Mean duration of rhGH therapy was 4.2 ± 0.9 years; rhGH dose was 0.3 ± 0.07 mg/kg/week. Height SDS at baseline was lower in rhGH-treated patients than in controls (-2.00 ± 1.02 versus -0.96 ± 1.11, p < 0.001). Baseline height SDS was significantly lower than target height SDS in both groups. Height SDS significantly improved from baseline to final height attainment in rhGH-treated patients, while it slightly decreased in controls (mean SDS variation 0.69 ± 1.05 in rhGH-treated cases versus -0.15 ± 1.2 in controls). Final height SDS was -1.25 ± 1.06 in rhGH-treated cases and -1.06 ± 1.17 in controls (p = 0.29). Target adjusted final height SDS was -0.91 ± 1.03 in rhGH-treated cases and -0.61 ± 1.17 in controls (p = 0.1).

CONCLUSIONS

Long-term rhGH therapy is able to reduce the linear growth deceleration of children with CKD, and ultimately to improve their final height, reducing the difference with target height.

Growth hormone therapy in children with CKD after more than two decades of practice

This review focuses on the evidence for the efficacy and safety of recombinant human growth hormone (rhGH) therapy in children with all stages of chronic kidney disease (CKD) and at all ages. It describes the improving height prognosis for our patients both with and without rhGH; explains the underlying hormonal abnormalities that provide the rationale for rhGH use in CKD and the endocrine changes that accompany treatment; and views on who warrants treatment, with what dose, and how long for.

Growth hormone, insulin-like growth factor-1, and the kidney: pathophysiological and clinical implications

Besides their growth-promoting properties, GH and IGF-1 regulate a broad spectrum of biological functions in several organs, including the kidney. This review focuses on the renal actions of GH and IGF-1, taking into account major advances in renal physiology and hormone biology made over the last 20 years, allowing us to move our understanding of GH/IGF-1 regulation of renal functions from a cellular to a molecular level. The main purpose of this review was to analyze how GH and IGF-1 regulate renal development, glomerular functions, and tubular handling of sodium, calcium, phosphate, and glucose. Whenever possible, the relative contributions, the nephronic topology, and the underlying molecular mechanisms of GH and IGF-1 actions were addressed. Beyond the physiological aspects of GH/IGF-1 action on the kidney, the review describes the impact of GH excess and deficiency on renal architecture and functions. It reports in particular new insights into the pathophysiological mechanism of body fluid retention and of changes in phospho-calcium metabolism in acromegaly as well as of the reciprocal changes in sodium, calcium, and phosphate homeostasis observed in GH deficiency. The second aim of this review was to analyze how the GH/IGF-1 axis contributes to major renal diseases such as diabetic nephropathy, renal failure, renal carcinoma, and polycystic renal disease. It summarizes the consequences of chronic renal failure and glucocorticoid therapy after renal transplantation on GH secretion and action and questions the interest of GH therapy in these conditions.

The insulin-like growth factor system and nutritional assessment

Over recent years there has been considerable interest in the role of the insulin-like growth factor (IGF) system in health and disease. It has long been known to be dysregulated in states of under- and overnutrition, serum IGF-I levels falling in malnourished patients and responding promptly to nutritional support. More recently, other proteins in this system have been observed to be dysregulated in both malnutrition and obesity. Currently no biochemical marker is sufficiently specific for use in screening for malnutrition, but levels may be valuable in providing information on nutritional status and in monitoring of nutritional support. All have limitations as nutritional markers in that their serum levels are influenced by factors other than nutritional status, most importantly the acute phase response (APR). Levels should be interpreted along with clinical findings and the results of other investigations such as C-reactive protein (CRP). This paper reviews data supporting the use of proteins of the IGF system as nutritional markers.

Insulin-like growth factors in normal and diseased kidney

This article reviews the physiology of the insulin-like growth factor (IGF) system in the kidney and the changes and potential role of this system in selected renal diseases. The potential therapeutic uses of recombinant human IGF-I for the treatment of acute and chronic kidney failure are briefly discussed.

Effectiveness of rhGH treatment on final height of renal-transplant recipients in childhood

BACKGROUND

Growth retardation is a considerable clinical problem in children with chronic kidney disease (CKD). Optimization of metabolic and nutritional parameters does not always lead to improved growth. Recombinant human growth hormone (rhGH) treatment has been used to improve height. Several studies in the literature have shown increased growth velocity, although data on the final height (FH) reached are scarce.

AIMS

We assessed the effect of rhGH on FH standard deviation score (SDS) in children with CKD following renal transplantation (RTx), comparing it with patients who did not receive rhGH (control group) but were treated with the same protocol and followed up in a single Center.

METHODS

Thirty-three patients received rhGH treatment until FH. Fourteen who refused rhGH therapy were included in the controls. Prognostic factors for FH and changes in glomerular filtration rate (GFR) during follow-up were also analyzed

RESULTS

FH SDS in rhGH-treated patients was significantly higher than in controls (-1.88 ± 1.14 vs -3.48 ± 1.19 SDS, respectively, p <0.05). In both groups, a similar reduction in GFR was observed. Height (SDS) at onset of rhGH treatment was the only statistically significant variable useful to predict response to treatment (p = 0.001).

CONCLUSION

Our findings confirm that rhGH is effective to improve FH in CKD RTx patients, without affecting kidney function.

Growth hormone for children with chronic kidney disease

BACKGROUND

Growth retardation is a common complication of chronic kidney disease (CKD) in children and is of concern to families. Recombinant human growth hormone (rhGH) treatment has been used to help short children with CKD attain a height more in keeping with their age group. However there are concerns about the long-term benefits of rhGH in significantly improving adult height as well as concerns about potential adverse effects (deterioration in native kidney function, increased acute rejection in kidney transplant recipients, benign intracranial hypertension).

OBJECTIVES

To evaluate the benefits and harms of rhGH treatment in children with CKD.

SEARCH METHODS

Randomised controlled trials (RCTs) were identified from the Cochrane Renal Group's Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 12, 2011), MEDLINE (from 1966), EMBASE (from 1980), article reference lists and through contact with local and international experts in the field.Date of last search: December 29, 2011

SELECTION CRITERIA

RCTs were included if they were carried out in children aged zero to 18 years, diagnosed with CKD, who were pre-dialysis, on dialysis or post-transplant; if they compared rhGH treatment with placebo/no treatment or two doses of rhGH treatments; and if they included height outcomes.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for risk of bias and extracted data from eligible studies. Data was pooled using a random effects model with calculation of mean difference (MD) for continuous outcomes with 95% confidence intervals (CI).

MAIN RESULTS

Sixteen studies (enrolling 809 children) were identified. Risk of bias assessment indicated that study quality was poor or poorly reported with only four and five studies respectively reporting adequate allocation concealment or blinding of study participants and investigators. Treatment with rhGH (28 IU/m²/wk) compared with placebo or no specific therapy resulted in a significant increase in height standard deviation score (HSDS) at one year (8 studies, 391 children: MD 0.82, 95% CI 0.56 to 1.07), and a significant increase in height velocity at six months (2 studies, 27 children: MD 2.85 cm/6 mo, 95% CI 2.22 to 3.48) and one year (7 studies, 287 children: MD 3.88 cm/y, 95% CI 3.32 to 4.44). Height velocity, though reduced, remained significantly greater than untreated children during the second year of therapy (1 study, 82 children: MD 2.30 cm/y, 95% CI 1.39 to 3.21). Compared to the 14 IU/m²/wk group, there was a 1.18 cm/y increase in height velocity in the 28 IU/m²/wk group (3 studies, 150 children: 1.18 cm/y, 95% CI 0.52 to 1.84) . The frequency of reported side effects of rhGH was generally similar to that of the control group.

AUTHORS' CONCLUSIONS

One year of 28 IU/m²/wk rhGH in children with CKD resulted in a 3.88 cm increase in height velocity above that of untreated patients. Studies were too short to determine if continuing treatment resulted in an increase in final adult height.

OPPORTUNITY&trade;: a large-scale randomized clinical trial of growth hormone in hemodialysis patients

BACKGROUND

Adult maintenance hemodialysis (MHD) patients experience high mortality and morbidity and poor quality of life (QoL). Markers of protein-energy wasting are associated with these poor outcomes. The OPPORTUNITY™ Trial examined whether recombinant human growth hormone (hGH) reduces mortality in hypoalbuminemic MHD patients. Secondary end points were effects on number of hospitalizations, cardiovascular events, lean body mass (LBM), serum proteins, exercise capacity, QoL and adverse events.

METHODS

We performed a randomized, double-blind, placebo-controlled, multicenter multinational trial stratified for diabetic status. Clinically, stable adult MHD patients with serum albumin <4.0 g/dL were randomized to subcutaneous injections of hGH, 20 μg/kg/day, or placebo. Planned treatment duration was 24 months for 2500 patients. The trial was terminated early due to slow recruitment.

RESULTS

Seven hundred and twelve patients were randomized until trial termination; 695 patients received at least one dose of trial medication. Mean treatment duration was 20 weeks (no completers). There were no differences between groups in all-cause mortality, cardiovascular morbidity or mortality, serum albumin, LBM, physical exercise capacity or QoL. The hGH group, compared to placebo, displayed a reduction in body weight, total body fat, serum high-sensitivity C-reactive protein and possibly homocysteine and an increase in serum high-density lipoprotein-cholesterol and transferrin levels.

CONCLUSIONS

Although the OPPORTUNITY™ Trial was terminated early, treatment with hGH, compared to placebo, improved certain cardiovascular risk factors but did not reduce mortality, cardiovascular events or improve nutritional factors or QoL. The power for showing differences was substantially reduced due to the marked decrease in treatment duration and sample size.

Use of rhGH in children with chronic kidney disease: lessons from NAPRTCS

We evaluated the utilization and potential benefits of recombinant human growth hormone (rhGH) in children with chronic kidney disease (CKD) and following renal transplantation in a large patient cohort. We queried the chronic renal insufficiency (CRI), dialysis, and transplant registries of the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) to characterize the frequency of rhGH utilization, factors related to its usage, and the relationship between rhGH usage and catch-up growth. Data from 6,505, 5,122, and 4,478 CRI, dialysis, and transplant patients, respectively, was evaluated. Percentage utilization of rhGH 2 years after registry entry was 22%, 33%, and 3% in children with a height standard deviation score (SDS)<-1 and age<17 years (termed candidate group) in CRI, dialysis, and transplant patients, respectively. Multivariate logistic regression analysis showed that the likelihood of using rhGH was significantly correlated with age, gender, geographical region of residence and height category within the candidate group (p<0.01). The use of rhGH was associated with catch-up growth in 27%, 11%, and 25% of candidate CRI, dialysis, and transplant patients, respectively. In the candidate group, percentage catch-up growth was highest in children who were Tanner stage 1-2, who comprised 19.4%, 7.1%, and 25.5% of the CRI, dialysis, and transplant patients, respectively. Using multiple regression analysis, the estimated impact of rhGH on final adult height (age>19 years) was 0.80, 0.50, and 0.19 SDS, in CRI, dialysis, and transplant patients, respectively. Thus, rhGH can improve height gain in some children with CKD. The use of rhGH appears to be most effective in prepubertal children with CRI.

Response of the growth plate of uremic rats to human growth hormone and corticosteroids

Children with chronic renal failure in general present growth retardation that is aggravated by corticosteroids. We describe here the effects of methylprednisolone (MP) and recombinant human growth hormone (rhGH) on the growth plate (GP) of uremic rats. Uremia was induced by subtotal nephrectomy in 30-day-old rats, followed by 20 IU kg-1 day-1 rhGH (N = 7) or 3 mg kg-1 day-1 MP (N = 7) or 20 IU kg-1 day-1 rhGH + 3 mg kg-1 day-1 MP (N = 7) treatment for 10 days. Control rats with intact renal function were sham-operated and treated with 3 mg kg-1 day-1 MP (N = 7) or vehicle (N = 7). Uremic rats (N = 7) were used as untreated control animals. Structural alterations in the GP and the expression of anti-proliferating cell nuclear antigen (PCNA) and anti-insulin-like growth factor I (IGF-I) by epiphyseal chondrocytes were evaluated. Uremic MP rats displayed a reduction in the proliferative zone height (59.08 +/- 4.54 vs 68.07 +/- 7.5 microm, P < 0.05) and modifications in the microarchitecture of the GP. MP and uremia had an additive inhibitory effect on the proliferative activity of GP chondrocytes, lowering the expression of PCNA (19.48 +/- 11.13 vs 68.64 +/- 7.9% in control, P < 0.0005) and IGF-I (58.53 +/- 0.96 vs 84.78 +/- 2.93% in control, P < 0.0001), that was counteracted by rhGH. These findings suggest that in uremic rats rhGH therapy improves longitudinal growth by increasing IGF-I synthesis in the GP and by stimulating chondrocyte proliferation.

Effects of insulin-like growth factor binding proteins in bone -- a matter of cell and site

The actions of the insulin-like growth factor (IGF)-system are controlled by six IGF-binding proteins (IGFBPs). The IGFBPs are thought to affect local effects of IGF-I and IGF-II due to higher affinity if compared to IGF-I receptors and due to cell-type specific IGFBP expression patterns. It was found in IGFBP knockout models that the IGFBP family is functionally redundant. Thus, functional analysis of potential effects of IGFBPs is dependent on descriptive studies and models of IGFBP overexposure in vitro and in vivo. In the literature, the role of the IGFBPs for bone growth is highly controversial and, to date, no systematic look has been taken at IGFBPs resolving functional aspects of IGFBPs at levels of cell types and specific locations within bones. Since IGFBPs are thought to represent local modulators of the IGF actions and also exert IGF-independent effects, this approach is particularly reasonable on a physiological level. By sorting the huge number of in part controversial results on IGFBP effects in bone present in the literature for distinct cell types and bone sites it is possible to generate a focused, more specific and a less controversial picture of IGFBP functions in bone.

Growth hormone treatment of non-growth hormone-deficient growth disorders

Although a large body of data on efficacy and safety of growth hormone (GH) treatment for various non-growth hormone-deficient (GHD) growth disorders has accumulated from a combination of clinical trial and postmarketing sources in the last 20 years or more, there remain limitations. Clinical trial data have the advantage of direct comparison of well-matched, randomized patient groups receiving treatment (or not) under comparable conditions and, as such, provide the highest quality evidence of efficacy. Clinical trials, however, are typically too small for any statistically valid assessment for safety, which is more comprehensively addressed using postmarketing data. Consequently, while the efficacy of GH treatment in children with non-GHD growth disorders has been solidly established and, based on the combination of the rigor of the clinical trial data and numerical power of the postmarketing data, no major concerns exist regarding safety, additional long-term data are required.

Growth hormone for children with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is an uncommon but important condition. Growth retardation, one of the complications of CKD, is of concern to families. Recombinant human growth hormone (rhGH) treatment has been used to help short children with CKD attain a height more in keeping with their age group. However, there are concerns that rhGH may have an adverse effect on the preservation of native kidney function, predispose to acute rejection in kidney transplant recipients, and cause benign intracranial hypertension and slipped capital femoral epiphysis.

OBJECTIVES

To evaluate the benefits and harms of rhGH treatment in children with CKD.

SEARCH STRATEGY

Randomised controlled trials (RCTs) were identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, article reference lists and through contact with local and international experts in the field. Date of most recent search: July 2005

SELECTION CRITERIA

RCTs were included if they were carried out in children aged 0-18 years, diagnosed with CKD, who were pre-dialysis, on dialysis or post-transplant; if they compared rhGH treatment with placebo/no treatment or two doses of rhGH treatments; and if they included height outcomes.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed studies for methodological quality and extracted data from eligible trials. Data was pooled using a random effects model with calculation of weighted mean difference (MD) for continuous outcomes and relative risk (RR) for categorical outcomes with 95% confidence intervals (CI).

MAIN RESULTS

Fifteen RCTs (629 children) were identified. Treatment with rhGH (28 IU/m(2)/wk) resulted in a significant increase in height standard deviation score (SDS) at one year (MD 0.78 SDS, 95% CI 0.52 to 1.04), and a significant increase in height velocity at six months (MD 2.85 cm/6 mo, 95%CI 2.22 to 3.48) and one year (MD 3.80 cm/y, 95%CI 3.20 to 4.39). Compared to the 14 IU/m(2)/wk group, there was a 1.34 cm/y (0.55 to 2.13) increase in height velocity in the 28 IU/m(2)/wk group. The frequency of reported side effects of rhGH were similar to that of the control group.

AUTHORS' CONCLUSIONS

One year of 28 IU/m(2)/wk rhGH in children with CKD resulted in a 3.80 cm/y increase in height velocity above that of untreated patients. Trials were too short to determine if continuing treatment resulted in an increase in final adult height.

Assessment and treatment of short stature in pediatric patients with chronic kidney disease: a consensus statement

Growth failure is a clinically important issue in children with chronic kidney disease (CKD) and is associated with significant morbidity and mortality. Many factors contribute to impaired growth in these children, including abnormalities in the growth hormone (GH)-insulin-like growth factor-I (IGF-I) axis, malnutrition, acidosis, and renal bone disease. The management of growth failure in children with CKD is complicated by the presence of other disease-related complications requiring medical intervention. Despite evidence of GH efficacy and safety in this population, some practitioners and families have been reluctant to institute GH therapy, citing an unwillingness to comply with daily injections, reimbursement difficulties, or impending renal transplantation. Suboptimal attention to growth failure management may be further compounded by a lack of clinical guidelines for the appropriate assessment and treatment of growth failure in these children. This review of growth failure in children with CKD concludes with an algorithm developed by members of the consensus committee, outlining their recommendations for appropriate steps to improve growth and overall health outcomes in children with CKD.

Circulating growth hormone binding protein levels and mononuclear cell growth hormone receptor expression in uremia

BACKGROUND

Resistance to growth hormone (GH) in end-stage renal disease (ESRD) causes growth retardation and muscle wasting. In humans, circulating GH binding protein (GHBP), the extracellular domain of the GH receptor that is shed into the circulation and is believed to reflect tissue GH receptor levels, is reduced in uremia and suggests that cellular GH receptor levels are correspondingly reduced. If true, this could be a cause of GH resistance. We set out to establish whether serum GHBP levels reflect cellular GH receptor levels and whether changes in serum GHBP levels are related to nutritional or inflammatory status.

METHODS

GH receptor protein expression in peripheral blood mononuclear cells (PBMC) from 21 ESRD and 14 normal subjects were analyzed by fluorochrome flow cytometry.

RESULTS

The GH receptor density and percent total PBMCs expressing the GH receptor were similar in the 2 groups, and there was no difference in percent GH receptor positive T or B cells or monocytes. In contrast, serum GHBP levels were 80% lower in ESRD. GHBP levels did not correlate with serum albumin, body mass index, or muscle mass but seemed to be partly related to the log serum C-reactive protein levels.

CONCLUSIONS

Serum GHBP levels are markedly reduced in ESRD; this seems to occur independent of nutritional status and may in part be caused by inflammation. Because GH receptor expression on PBMC of ESRD and control subjects was similar, our findings argue against a reduction in GH receptor as a cause of GH resistance and the use of serum GHBP levels as a reliable marker of specific tissue GH receptor levels.

Insulin-like growth factor binding proteins in development

IGFBPs regulate growth and development by regulating IGF transport to tissues and IGF bioavailability to IGF receptors at cell membrane level. IGFBP excess leads predominantly to inhibition of IGF action and growth retardation with impaired organogenesis. Absence of human and also mouse ALS leads to decreased IGF-I levels in circulation and causes mild growth retardation. Although IGFBP KO mice demonstrate relatively minor phenotypes, the possibility of compensatory mechanisms that mask the phenotypic manifestation of lack of individual binding proteins needs to be further investigated. Recent studies of hepatic regeneration in IGFBP-1 KO mice and also with mutant IGFBP-3 Tg mice provide some limited support for the existence of IGF-independent mechanism of action in vivo.

Insuficiência renal crônica e hormônio de crescimento: efeitos no eixo GH-IGF e na leptina

OBJETIVO: Avaliar as alterações de IGF-1, IGFBP-3, leptina e insulina após o uso de doses de reposição de hormônio de crescimento recombinante humano (rhGH) em crianças baixas pré-púberes com insuficiência renal crônica (IRC). CASUÍSTICA E MÉTODOS: Em 11 crianças (3F:8M), com idade média de 9,6 anos, em uso de rhGH (0,23mg/Kg/semana) por 12 meses, foram dosados (antes, 6 e 12 meses após o início do tratamento com rhGH) leptina, insulina, glicemia, IGF-1 e IGFBP-3. RESULTADOS: As concentrações séricas de leptina, insulina e glicemia não variaram significativamente no decorrer do uso do rhGH, sendo observado o padrão de leptina e glicemia normais, com hiperinsulinemia. Houve aumento significativo da IGF-1 e IGFBP-3 durante o uso do rhGH. CONCLUSÕES: O uso de doses de reposição de rhGH durante 12 meses em um grupo selecionado de crianças com IRC propiciou aumento significativo da concentração sérica de IGF-1 e IGFBP-3, com leptinemia normal e resistência insulínica.

Growth Hormone Determines Sexual Dimorphism of Hepatic Cytochrome P450 3A4 Expression in Transgenic Mice

The impact of age and sex on the expression of hepatic cytochrome P450 3A4 (CYP3A4) was recently determined in a transgenic mouse line carrying the human CYP3A4 gene. To further investigate the physiological regulation of human CYP3A genes, a novel transgenic mouse line was generated using a bacterial artificial chromosome clone containing both CYP3A4 and CYP3A7 genes. CYP3A7 expression was observed in transgenic mouse fetal livers, whereas CYP3A4 exhibited developmental expression characterized by sexual dimorphism in postpubertal livers. Hepatic CYP3A4 protein and RNA were expressed in immature transgenic male mice and became undetectable after 6 weeks of age, whereas CYP3A4 was expressed in both immature and adult females. CYP3A4 was markedly elevated by the xenobiotic receptor activator phenobarbital in both male and female livers, demonstrating drug induction of the CYP3A4 transgene in this mouse model. Furthermore, continuous infusion of recombinant growth hormone (GH) in transgenic male mice, overriding the pulsatile male plasma GH profile, increased hepatic CYP3A4 mRNA and protein to normal female levels. Continuous GH treatment also feminized the expression of endogenous murine Cyp2b and Cyp3a44 genes. Thus, human CYP3A4 contains all of the gene regulatory sequences required for it to respond to endogenous hormonal regulators of developmental expression and sexual dimorphism, in particular GH. These findings may help elucidate the role of GH in determining the sex-dependent expression of CYP3A4 in human liver and suggest that GH therapy may alter the pharmacokinetic and pharmacodynamic properties of CYP3A4 substrates, leading to enhanced metabolism and disposition of drugs in men.

Growth hormone treatment in 35 prepubertal children with achondroplasia: a five-year dose-response trial

BACKGROUND

Achondroplasia is a skeletal dysplasia with extreme, disproportionate, short stature.

AIM

In a 5-y growth hormone (GH) treatment study including 1 y without treatment, we investigated growth and body proportion response in 35 children with achondroplasia.

METHODS

Patients were randomized to either 0.1 IU/kg (n = 18) or 0.2 IU/kg (n = 17) per day. GH treatment was interrupted for 12 mo after 2 y of treatment in prepubertal patients to study catch-down growth. Mean height SDS (HSDS) at start was -5.6 and -5.2 for the low- and high-dose groups, respectively, and mean age 7.3 and 6.6 y.

RESULTS

Mean growth velocity (baseline 4.5/4.6 cm/y for the groups) increased significantly by 1.9/3.6 cm/y during the first year and by 0.5/1.5 cm/y during the second year. During the third year, a decrease of growth velocity was observed at 1.9/1.3 cm/y below baseline values. HSDS increased significantly by 0.6/0.8 during the first year of treatment and in total by 1.3/1.6 during the 5 y of study. Sitting height SDS improved significantly from -2.1/-1.7 to -0.8/0.2 during the study. Body proportion (sitting height/total height) or arm span did not show any significant change.

CONCLUSION

GH treatment of children with achondroplasia improves height during 4 y of therapy without adverse effect on trunk-leg disproportion. The short-term effect is comparable to that reported in Turner and Noonan syndrome and in idiopathic short stature.

Growth hormone resistance in uremia, a role for impaired JAK/STAT signaling

Resistance to growth hormone (GH) is a significant complication of advanced chronic renal failure. Thus while the circulating GH levels are normal or even elevated in uremia, resistance to the hormone leads to stunting of body growth in children and contributes to muscle wasting in adults. Insensitivity to GH is the consequence of multiple defects in the GH/insulin-like growth factor-1 (IGF-1) system. Expression of the GH receptor may be reduced, although this is not a consistent finding, GH activation of the Janus kinase 2-signal transducer (JAK2) and activator of transcription (STAT) signal transduction pathway is depressed and this leads to reduced IGF-1 expression, and finally there is resistance to IGF-1, a major mediator of GH action. We review these various defects with an emphasis on the GH-activated JAK2-STAT5 pathway, since this pathway is essential for normal body growth and there has been recent progress in our understanding of the perturbations that occur in uremia.

Growth hormone/insulin-like growth factor system in children with chronic renal failure

Disturbances of the somatotropic hormone axis play an important pathogenic role in growth retardation and catabolism in children with chronic renal failure (CRF). The apparent discrepancy between normal or elevated growth hormone (GH) levels and diminished longitudinal growth in CRF has led to the concept of GH insensitivity, which is caused by multiple alterations in the distal components of the somatotropic hormone axis. Serum levels of IGF-I and IGF-II are normal in preterminal CRF, while in end-stage renal disease (ESRD) IGF-I levels are slightly decreased and IGF-II levels slightly increased. In view of the prevailing elevated GH levels in ESRD, these serum IGF-I levels appear inadequately low. Indeed, there is both clinical and experimental evidence for decreased hepatic production of IGF-I in CRF. This hepatic insensitivity to the action of GH may be partly the consequence of reduced GH receptor expression in liver tissue and partly a consequence of disturbed GH receptor signaling. The actions and metabolism of IGFs are modulated by specific high-affinity IGFBPs. CRF serum has an IGF-binding capacity that is increased by seven- to tenfold, leading to decreased IGF bioactivity of CRF serum despite normal total IGF levels. Serum levels of intact IGFBP-1, -2, -4, -6 and low molecular weight fragments of IGFBP-3 are elevated in CRF serum in relation to the degree of renal dysfunction, whereas serum levels of intact IGFBP-3 are normal. Levels of immunoreactive IGFBP-5 are not altered in CRF serum, but the majority of IGFBP-5 is fragmented. Decreased renal filtration and increased hepatic production of IGFBP-1 and -2 both contribute to high levels of serum IGFBP. Experimental and clinical evidence suggests that these excessive high-affinity IGFBPs in CRF serum inhibit IGF action in growth plate chondrocytes by competition with the type 1 IGF receptor for IGF binding. These data indicate that growth failure in CRF is mainly due to functional IGF deficiency. Combined therapy with rhGH and rhIGF-I is therefore a logical approach.

Free insulin-like growth factors -- measurements and relationships to growth hormone secretion and glucose homeostasis

IGF-I is a multipotent growth factor with important actions on normal tissue growth and regeneration. In addition, IGF-I has been suggested to have beneficial effects on glucose homeostasis due to its glucose lowering and insulin sensitizing actions. However, not all effects of IGF-I are considered to be favorable; thus, epidemiological studies suggest that IGF-I is also involved in the development of common cancers, atherosclerosis and type 2 diabetes. The biological actions of IGF-I are modulated by at least six IGF-binding proteins, which bind approximately 99% of the circulating IGF-I pool. So far, most in vivo studies have used serum or plasma total (extractable IGF-I) as an estimate of the bioactivity of IGF-I in vivo. However, within the last decade, validated assays for measurement of free IGF-I have been described. This review aims to discuss the current assays for free IGF-I and their advances in relation to the traditional measurement of total IGF-I. The literature overview will focus on the role of circulating free versus total IGF-I in the feedback regulation of GH release, and the possible involvement of the circulating IGF-system in glucose homeostasis.

Growth hormone therapy before and after pediatric renal transplant

Children undergoing successful renal transplantation anticipate optimal growth and development. The use of rhGH pre- and post-Tx has been evaluated and supported by randomized control trials. Several strategies are required to maximize the potential benefit of this treatment in the renal population including provision of adequate nutrition intake, following bone parameters with appropriate interventions, and strategies to reduce steroid therapy including utilization of alternate day steroid treatment. Studies are required to further assess the impact of rhGH on renal allograft function, rejection risk, and allograft ultrastructural changes.

Differential effects of insulin-like growth factor binding proteins-1, -2, -3, and -6 on cultured growth plate chondrocytes

BACKGROUND

In children with chronic renal failure (CRF), impairment of longitudinal growth is in part due to excess amounts of circulating high-affinity insulin-like growth factor binding proteins (IGFBPs) that might decrease or prevent insulin-like growth factor (IGF) binding to its signaling receptor. However, it appears from the clinical studies that various IGFBPs may have contrasting effects on longitudinal growth. Because of the potential importance of the IGFBPs as modulators of longitudinal growth in pediatric CRF, the aim of the present study was to investigate the biological effects of IGFBP-1, -2, -3, and -6 on cultured growth plate chondrocytes that express the type 1 IGF receptor.

METHODS

The effects of exogenous IGFBPs on IGF-independent and IGF-dependent proliferation of rat growth plate chondrocytes in primary culture were investigated. Proliferation was assessed by colony formation of agarose-stabilized long-term suspension cultures and by the [3H]thymidine assay. The effects of IGFBPs on IGF-I binding and the binding of IGFBPs to chondrocytes were assessed by binding studies with radiolabeled proteins in monolayer culture.

RESULTS

Intact IGFBP-1, IGFBP-2 and IGFBP-6 inhibited in equimolar concentration the IGF-I- and IGF-II-stimulated DNA synthesis and cell proliferation, whereas the biological activity of IGFBP-3 was complex. It had an IGF-independent antiproliferative effect and also inhibited IGF-dependent chondrocyte proliferation under coincubation conditions, whereas under preincubation conditions IGFBP-3 enhanced IGF-I-responsiveness. Studies on the mechanism by which IGFBP-3 potentiated IGF activity demonstrated that under preincubation conditions IGFBP-3 is capable to associate with the cell membrane and to facilitate IGF-I cell surface binding.

CONCLUSIONS

Intact IGFBP-1, IGFBP-2 and IGFBP-6 act exclusively as growth inhibitors on IGF-dependent proliferation of growth plate chondrocytes. IGFBP-3, however, can either inhibit IGF-independent and IGF-dependent cell proliferation, or enhance IGF responsiveness of chondrocytes dependent on the temporal relationship to the IGF exposure.

Anthropometry of the trunk and extremities in nutritional assessment of children with chronic renal failure

OBJECTIVE

Comparison of anthropometric parameters of the trunk and extremities between 2 groups of children with chronic renal failure (CRF) with different levels of nutritional status and healthy controls.

DESIGN

A prospective cross-sectional study.

SETTINGS

Department of Physiology and Anthropology, University Ss. Cyril and Methodius, Skopje.

PATIENTS

Twenty-one patients with a mean age of 10.5 +/- 3.2 years (10 boys and 11 girls) with mild to moderate CRF were divided into well-nourished (chronic renal failure children [CRFC] I) and undernourished (CRFC II) children according to their nutritional status. The control group was 22 healthy children with a mean age of 10.7 +/- 3.8 years (10 boys and 12 girls). Nutritional status of the children was assessed by comparing anthropometric parameters with National Center for Health Statistics references.

INTERVENTIONS

Anthropometry.

MAIN OUTCOME MEASUREMENTS

Body weight, height, sitting height, arm and leg length, knee height, chest circumference, midarm circumference, triceps skin-fold thickness, and upper arm muscle and fat area.

RESULTS

Mean sitting height, leg length, and chest circumference were significantly lower in both the CRFC I group (67.8 +/- 3.5, 57.5 +/- 4.2, and 53.0 +/- 3.9 cm) and the CRFC II group (65.6 +/- 2.2, 56.1 +/- 4.1, and 50.6 +/- 2.7 cm) compared with the healthy controls (72.5 +/- 2.9, 61.3 +/- 3.5, and 62.4 +/- 4.1 cm, respectively). The highest significant correlations to height were for sitting height (r = +0.82, P <.05) and knee height (r = +0.72, P <.05) in CRFC I and for leg length (r = +0.74, P <.05) in CRFC II. There was no correlation between anthropometric parameters of the trunk and extremities and upper muscle and fat area in both groups of CRF children.

CONCLUSION

The sitting height, knee height, and leg length can be used in nutritional and growth assessment when it is impossible to make a reliable measurement of height in CRF children.

Recombinant human growth hormone treatment, using two dose regimens in children with chronic renal failure--a report on linear growth and adverse effects

The aim of this study was to study the efficiency and the adverse effects of 2 or 4 IU/m2/day of growth hormone (GH) in the first year and 4 IU/m2/day in the second. Of 29 growth-retarded children with chronic renal failure (CRF) (aged 3.4-15.1 years), 23 completed the first year of therapy, and 16 completed the second year. Height velocity SDS (HVSDS) increased in the first year in the low-dose group with 3.0, and 3.8 in the high-dose group. In the second year, HVSDS increased by 1.3 in the low-dose group and by 2.1 in high-dose group (p < 0.05). The IGF-I/IGFBP-3 ratio rose identically during the first year (p < 0.01). The retarded bone age did not advance inappropriately. The integrated insulin levels (AUC) increased significantly after 1 year of therapy in both groups. HbA1c, levels did not change. The number of adverse events was highest in the low-dose group, in which one patient developed overt insulin dependent diabetes mellitus. In conclusion, glucose metabolism should be monitored in children with CRF during rhGH-treatment. GH therapy in our patients resulted in a significant increase in height velocity with no inappropriate bone age progression and few serious adverse effects, all without relation to the dose of rhGH. The low start dose (2 IU/m2/ day) was of no advantage compared to the high dose.

Intact IGF-binding protein-4 and -5 and their respective fragments isolated from chronic renal failure serum differentially modulate IGF-I actions in cultured growth plate chondrocytes

Impairment of longitudinal growth among children with chronic renal failure (CRF) may be partly attributable to the inhibition of insulin-like growth factor (IGF) activity by an excess amount of high-affinity IGF-binding proteins (IGFBP). Elevated levels of immunoreactive IGFBP-4 in CRF serum are inversely correlated with the standardized heights of these children, whereas levels of IGFBP-5, which circulates mainly as proteolyzed fragments, are positively correlated with growth parameters. To delineate the respective effects of these IGFBP on growth cartilage, the biologic effects of intact and fragmented forms of IGFBP-4 and IGFBP-5 on rat growth plate chondrocytes in primary cultures were characterized. Intact IGFBP-4 and IGFBP-5 and the amino-terminal fragment IGFBP-5(1-169) were recombinant proteins; the carboxy-terminal fragments IGFBP-5(144-252) and IGFBP-4(136-237) and the amino-terminal fragment IGFBP-4(1-122) were purified to homogeneity from CRF hemofiltrates. Intact IGFBP-4 and, to a lesser extent, IGFBP-4(1-122) inhibited IGF-I-induced cell proliferation. In contrast, intact IGFBP-5 was stimulatory in the absence or presence of exogenous IGF-I, whereas the amino-terminal fragment IGFBP-5(1-169) was inhibitory. Studies on the mechanism by which IGFBP-4 and IGFBP-5 exert opposite effects on chondrocyte proliferation demonstrated that intact IGFBP-4 prevented the binding of (125)I-IGF-I to chondrocytes, whereas intact IGFBP-5 enhanced ligand binding and was able to bind specifically to the cell membrane. These data suggest that intact IGFBP-4 and, to a lesser extent, IGFBP-4(1-122) act exclusively as growth-inhibitory binding proteins in the growth cartilage. IGFBP-5, however, can either stimulate (if it remains intact) or inhibit (if amino-terminal forms predominate) IGF-I-stimulated chondrocyte proliferation.

Growth hormone treatment in children with chronic renal failure: a meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the benefits and side effects of recombinant human growth hormone (hGH) treatment in children with chronic renal failure.

METHODS

Two reviewers independently assessed relevant randomized controlled trials for methodologic quality, extracted data, and estimated summary treatment effects by use of a random effects model.

RESULTS

Ten randomized controlled trials involving 481 children were identified. Treatment with hGH (28 IU/m(2)/wk) resulted in a significant increase in height standard deviation score at 1 year (4 trials, weighted mean difference [WMD] = 0.77, 95% CI = 0.51 to 1.04), and a significant increase in height velocity at 6 months (2 trials, WMD = 5.7 cm/y, 95% CI 4.4 to 7.0) and 1 year (2 trials, WMD = 4.1 cm/y, 95% CI 2.6 to 5.6), but there was no further increase in height indexes during the second year of administration. Compared with the 14 IU/m(2)/wk group, there was an increase of 1.4 cm/y (0.6 to 2.2) in height velocity in the group treated with 28 IU/m(2)/wk. The frequency of reported side effects of hGH were similar to that of the control group.

CONCLUSION

On average, 1 year of treatment with 28 IU/m(2)/wk hGH in children with chronic renal failure results in an increase of 4 cm/y in height velocity above that of untreated control subjects, but there was no demonstrable benefit for longer courses or higher doses of treatment.

Impaired JAK-STAT signal transduction contributes to growth hormone resistance in chronic uremia

Chronic renal failure (CRF) is associated with resistance to the growth-promoting and anabolic actions of growth hormone (GH). In rats with CRF induced by partial renal ablation, 7 days of GH treatment had a diminished effect on weight gain and hepatic IGF-1 and IGFBP-1 mRNA levels, compared with sham-operated pair-fed controls. To assess whether GH resistance might be due to altered signal transduction, activation of the JAK-STAT pathway was studied 10 or 15 minutes after intravenous injection of 5 mg/kg GH or vehicle. Hepatic GH receptor (GHR) mRNA levels were significantly decreased in CRF, but GHR protein abundance and GH binding to microsomal and plasma membranes was unaltered. JAK2, STAT1, STAT3, and STAT5 protein abundance was also unchanged. However, GH-induced tyrosine phosphorylation of JAK2, STAT5, and STAT3 was 75% lower in the CRF animals. Phosphorylated STAT5 and STAT3 were also diminished in nuclear extracts. The expression of the suppressor of cytokine signaling-2 (SOCS-2) was increased twofold in GH-treated CRF animals, and SOCS-3 mRNA levels were elevated by 60% in CRF, independent of GH treatment. In conclusion, CRF causes a postreceptor defect in GH signal transduction characterized by impaired phosphorylation and nuclear translocation of GH-activated STAT proteins, which is possibly mediated, at least in part, by overexpression of SOCS proteins.

Avascular necrosis of the femoral head in children with chronic renal disease

PURPOSE

To determine the incidence of avascular necrosis (AVN) of the femoral head in children with chronic renal failure.

MATERIALS AND METHODS

Pelvic radiographs in 205 children (age range, 6 months to 16 years; mean age, 6 years +/- 3.5 [SD]) with chronic renal failure were reviewed. Serial radiographs were obtained every 6 months for 1-7 years (mean, 3 years +/- 2) to assess the presence of AVN of the femoral head; six children had metabolic renal disease, 21 had acquired renal disease, and 178 had structural renal lesions.

RESULTS

Radiographic findings of AVN were seen in 14 of 205 patients (approximately one in every 15). The frequency of AVN was similar in boys and girls; AVN was observed in 11 (6.9%) of 159 boys and in three (6.5%) of 46 girls and was not related to the duration of renal disease, type of renal disease, or growth hormone therapy. Affected children were frequently asymptomatic, and, when present, the clinical complaints were mild. In two instances, AVN developed while the patients were receiving corticosteroids before entering this study.

CONCLUSION

The results of this study indicate that AVN of the femoral head is a frequent complication in children with chronic renal failure, occurring in approximately 7% of this population. Unlike Legg-Calvé-Perthes disease, AVN in children with chronic renal failure is frequently asymptomatic and has no sex predilection.

Growth hormone for children with chronic renal failure

OBJECTIVES

To evaluate the benefits and harms of recombinant human growth hormone (hGH) treatment in children with chronic renal failure (CRF).

SEARCH STRATEGY

Published and unpublished randomised controlled trials (RCTs) were identified from the Cochrane Controlled Trials Register, Medline, Embase, article reference lists and through contact with local and international experts in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) were included if they were carried out in children aged 0-18 years, diagnosed with CRF who are pre-dialysis, on dialysis or post-transplant; if they compared hGH treatment with placebo/no treatment or two doses of hGH treatments; and if they included height outcomes.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed studies for methodological quality and extracted data from eligible trials. The primary outcome measure was difference in mean change in height standard deviation score (SDS). Secondary outcome measures included change in height SDS from treatment onset to completion, change in height SDS during puberty, change in height velocity, final height, quality of life and adverse effects. To estimate summary treatment effects, data was pooled using a random effects model with calculation of weighted mean difference (WMD) for continuous outcomes and relative risk for categorical outcomes.

MAIN RESULTS

Ten RCTs involving 481 children were identified. Treatment with hGH (28 IU/m(2)/wk) resulted in a significant increase in height standard deviation score (SDS) at one year (four trials, WMD0.77, 95% confidence limits (CI) 0.51 to 1.04), and a significant increase in height velocity at six months (two trials, WMD 5.7 cm/yr, 95%CI 4.4 to 7.0) and one year (two trials, WMD 4.1 cm/yr, 95%CI 2.6 to 5.6), but there was no further increase in height indices during the second year of administration. Compared to the 14 IU/m(2)/wk group, there was a 1.4 cm/yr (0.6 to 2.2) increase in height velocity in the 28 IU/m(2)/wk group. The frequency of reported side effects of hGH were similar to that of the control group.

REVIEWER'S CONCLUSIONS

On average, one year of 28 IU/m(2)/wk hGH in children with CRF results in a 4 cm/yr increase in height velocity above that of untreated controls, however, it is not certain if this will result in an increase in final adult height. Benefits of longer courses or higher doses of treatment warrants further study.

Anthropometric measures and risk of death in children with end-stage renal disease

We evaluated the association between anthropometric measurements and death among pediatric patients with end-stage renal disease (ESRD) using data from the Pediatric Growth and Development Special Study (PGDSS) from the US Renal Data System. Height, growth velocity, and body mass index (BMI) were used for the analysis of 1,949 patients in the PGDSS. To standardize these measurements, SD scores (SDSs) were calculated using population data from the Third National Health and Nutrition Examination Survey. Using Cox proportional hazards models, we assessed the association between anthropometric measures and death, controlling for demographic factors and stratifying by age. Multivariate analysis showed that each decrease by 1 SDS in height was associated with a 14% increase in risk for death (adjusted relative risk [aRR], 1.14; 95% confidence interval [CI], 1.02 to 1.27; P = 0.017). For each 1 SDS decrease in growth velocity among patients in our sample, the risk for death increased by 12% (aRR, 1.12; 95% CI, 1.00 to 1.25; P = 0.043). There was a statistically significant U-shaped association between BMI and death (P = 0.001), with relatively low and high BMIs associated with an increased risk for death. In children with ESRD, growth delay and extremes in BMI are associated with an increased risk for mortality.

The impact of recombinant human growth hormone treatment during chronic renal insufficiency on renal transplant recipients

OBJECTIVE

To evaluate post-transplant outcomes for patients treated with human growth hormone (rhGH) during the course of chronic renal insufficiency (CRI).

STUDY DESIGN

Patients (the "cohort" group) were identified who had been enrolled in 2 controlled studies to determine the efficacy and safety of rhGH in growth-retarded children with CRI and were subsequently enrolled in the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) and received a renal transplant. Patient survival, graft survival, time to first acute rejection episode, causes of graft failure, adverse events, and serial growth data from transplant to 60 months were evaluated. Data from the cohort group of 102 patients were compared with data from 4913 primary transplants from "other NAPRTCS" recipients (the "control" group).

RESULTS

No significant difference was seen in patient survival or graft survival, incidence of acute rejection episode, or time to first rejection episode between the cohort and control groups. No specific adverse events were attributable to previous rhGH treatment. Only 2 patients had post-transplant lymphoproliferative disease in the cohort group, with no other malignancies reported. The mean height z scores in the cohort group at baseline and 60 months after transplant were -1.92 and -1.90, and the Deltaz score at 60 months was +0.20 compared with the control group (-1.88 and -2.10).

CONCLUSIONS

Treatment of growth-retarded patients with CRI does not adversely affect graft function after renal transplantation. "Catch-down" growth does not occur after renal transplantation.

Serum-free insulin-like growth factor I correlates with clearance in patients with chronic renal failure

Serum-free insulin-like growth factor I correlates with clearance in patients with chronic renal failure.

BACKGROUND

Chronic renal failure (CRF) results in major changes in the circulating growth hormone (GH)/insulin-like growth factor (IGF) system. However, there are only limited data on changes in free IGF-I in CRF.

METHODS

Matched groups of nondiabetic, nondialyzed patients with CRF (N = 25) and healthy controls (N = 13) were compared. The creatinine clearance (CCr) based on a 24-hour urine collection ranged from 3 to 59 and 89 to 148 ml/min/1.73 m2 in patients and controls, respectively. Overnight fasting serum samples were analyzed for free and total IGF-I and -II, and IGF-binding protein (IGFBP)-1, -2, and -3. Additionally, intact as well as proteolyzed IGFBP-3 was determined.

RESULTS

The patients had reduced serum-free IGF-I (-53%) and increased levels of total IGF-II (40%), IGFBP-1 (546%), and IGFBP-2 (270%, P < 0.05). Serum total IGF-I and free IGF-II were normal. Also, serum levels of immunoreactive IGFBP-3 were elevated (33%, P < 0.05), but this could be explained by an increased abundance of IGFBP-3 fragments, as ligand blotting showed no difference in levels of intact IGFBP-3. Accordingly, patients had an increased proteolysis of IGFBP-3 in vivo (17%) and in vitro (7%, P < 0.05). In patients, free IGF-I levels correlated positively with CCr (r2 = 0.38, P < 0.002) and inversely with IGFBP-1 (r2 = 0.69, P < 0. 0001) and IGFBP-2 (r2 = 0.41, P < 0.0007), whereas CCr was inversely correlated with levels of IGFBP-1 (r2 = 0.48, P < 0.0001) and IGFBP-2 (r2 = 0.63, P < 0.0001).

CONCLUSIONS

These data strongly support the hypothesis that CRF-related growth failure and tissue catabolism are caused by an increased concentration of circulating IGFBP-1 and -2, resulting in low serum levels of free IGF-I and thus IGF-I bioactivity. In addition, low levels of free IGF-I may explain the increased secretion of GH in CRF.

Pediatric experience with intradialytic parenteral nutrition and supplemental tube feeding

Good nutrition is necessary to maximize the potential for growth and development in the pediatric age-group, but children, like adults with chronic renal failure and end-stage renal disease, may be anorectic and eat poorly. Infants and adolescents are at special risk because of the intense demands of growth during the first 2 years of life and again during puberty. Neurodevelopment is also adversely affected by poor nutrition, especially in infants. Approximately two-thirds of pediatric dialysis patients are treated with chronic peritoneal dialysis, which results in significant protein losses in the dialysis effluent that can contribute to protein-calorie malnutrition. Meeting the nutritional needs of pediatric patients usually requires supplemental sources, such as intradialytic parenteral nutrition (IDPN) or tube feeding. Little is known about the effectiveness or desirability of IDPN in pediatric patients. More studies, especially of amino acid-based dialysis fluids for chronic peritoneal dialysis, need to be done before making IDPN a standard for pediatrics. Supplemental nasogastric or gastrostomy tube feedings have been very successful in maintaining and improving growth in infants, but no studies are available to evaluate their success in older children and adolescents. Recombinant growth hormone therapy, in addition to good nutrition and control of other growth factors such as acidosis, renal osteodystrophy, and chronic volume depletion, may be necessary for most growth-retarded children with chronic renal failure to achieve normal adult height.

Bioactivity of a 29-kilodalton insulin-like growth factor binding protein-3 fragment present in excess in chronic renal failure serum

Children with chronic renal failure (CRF) have normal or high serum levels of GH, IGF-I, and IGF-II. Despite this, the serum of CRF patients has low IGF bioactivity, which may contribute to CRF growth failure. Recent studies suggest that excess IGF binding proteins (IGFBPs) in the approximately 35-kD fractions of CRF serum contribute to this low IGF bioactivity. This report characterizes a 29-kD form of IGFBP-3, IGFBP-3(29), which accumulates in the approximately 35-kD fractions of CRF serum and peritoneal dialysate. Deglycosylation and [125I]IGF ligand blot studies show that IGFBP-3(29) is a glycosylated IGFBP-3 fragment with low affinity for IGF peptides. Using an IGFBP-3 antibody column, IGFBP-3(29) was purified to homogeneity from the approximately 35-kD fractions of peritoneal dialysate from children with CRF. Compared with native IGFBP-3, pure IGFBP-3(29) has a 4-10-fold lower affinity for IGF-II and a 200-fold lower affinity for IGF-I. Consistent with the binding data, IGFBP-3(29) inhibited IGF-II-stimulated thymidine incorporation in chondrosarcoma cells, but was a less potent inhibitor than native IGFBP-3; also, native IGFBP-3 clearly inhibited IGF-I-stimulated thymidine incorporation in chondrosarcoma cells and potentiated IGF-I-stimulated aminoisobutyric acid uptake in bovine fibroblasts, but higher concentrations of IGFBP-3(29) had no effect on these IGF-I actions. Thus, the 29-kD IGFBP-3 form that accumulates in CRF serum and extravascular spaces is an IGFBP-3 fragment that may modulate IGF-II, but not IGF-I, effects on target tissues. Whether IGFBP-3(29) plays any role in the growth failure of children with CRF remains to be determined.

Effects of renal failure on the growth hormone-insulin-like growth factor axis

Children with chronic renal failure (CRF) often have retarded growth, and abnormalities of the growth hormone-insulin-like growth factor (GH-IGF) axis in CRF may contribute to this growth failure. The serum GH and IGF levels are normal in these children, but IGF bioactivity is low as a result of excess IGF binding proteins (IGFBPs) in the 35 kd serum fractions. The levels of intact IGFBP-1, -2, and -6 and of a 29 kd IGFBP-3 fragment are all high, and the IGFBP-1 and -2 levels correlate negatively with height. Children with CRF who are treated with GH show catch-up growth that correlates positively with the increase in each component of the 150 kd serum ternary complex (acid-labile subunit, IGFBP-3, IGF-I, and IGF-II). Consistent with this observation, the increase in IGFBP-3 levels is confined to the 150 kd serum fractions. Serum levels of IGFBP-1, -2, and -6 do not rise, but serum IGF bioactivity does. Thus GH appears to induce an increase in the ternary complex in the serum of children with CRF. It is possible that IGFs released by the 150 kd serum complex promote growth by overcoming the inhibitory effects of excess IGFBPs in the 35 kd serum fractions.