Effects of growth hormone on kidney function in pediatric transplant recipients

Growth after renal transplantation

Growth may be severely impaired in children with chronic renal insufficiency. Since short stature can have major consequences on quality of life and self-esteem, achieving a 'normal' height is a crucial issue for renal transplant recipients. However, despite successful renal transplantation, the final height attained by most recipients is not the calculated target height. Catch-up growth spurts post-transplantation are usually insufficient to compensate for the retardation in growth that has occurred during the pre-transplant period. Longitudinal growth post-transplantation is therefore influenced by the age at transplantation but also by subsequent allograft function and steroid exposure, both of which interfere with the growth hormone/insulin-like growth factor axis. The management of growth retardation in renal transplant recipients includes adequate nutritional intake, correction of metabolic acidosis, prevention of bone disease, steroid-sparing strategies and a supraphysiological dose of recombinant human growth hormone in selected cases.

Growth after organ transplantation

Growth is an important feature of childhood, but it is usually impaired before and after organ transplantation. Modest catch-up growth often occurs after renal transplantation. Nevertheless, patients remain short due to the effects of steroids used for immunosuppression. Children with chronic liver failure are also growth impaired, although not to the same extent. They also frequently have poor catch up growth after transplantation, again due to steroids. There are several randomized controlled clinical trials reporting growth hormone (GH) use after renal transplantation. These consistently show a beneficial effect of GH on linear growth. Patients with histories of frequent acute rejections before GH may have increased risk of acute rejection during treatment. Few data exist on liver transplant patients, although GH also appears effective. GH use may be safe and effective for renal transplant recipients who have been stable without acute rejection episodes. There needs to be long-term study of GH use in liver and renal transplant patients. It is critical to focus efforts on improving growth in renal failure before transplantation through GH use and to improve posttransplant growth in all recipients by minimizing steroid exposure.

Current status of kidney transplant: update 2003

Pediatric transplantation has seen remarkable advances over the past two decades with reduced morbidity and mortality, reduced rejection rates, and improved long-term patient and allograft survival. Infants currently have short-term patient and allograft survival rates better than any other age group; short-term allograft survival rates in CD recipients are equal to those in LD recipients. With decreased rejection, long-term allograft survival is improving dramatically. Transplantation allows for much reduced risks and improved metabolic status, growth and development, and more normal social interactions. The future of transplantation continues to be exciting, with opportunities for reduced immunosuppressive medications and their side effects, and the elusive goal of transplantation tolerance seems within reach.

Growth hormone accelerates immune recovery following allogeneic T-cell-depleted bone marrow transplantation in mice

OBJECTIVE

To test in a murine model whether recombinant human growth hormone can promote immune recovery after allogeneic T-cell-depleted bone marrow transplantation.

MATERIALS AND METHODS

Lethally irradiated (8.5 Gy) BALB/c mice (H2(d)) were transplanted with 5 x 10(6) T cell-depleted bone marrow cells from C57BL/6 mice (H2(b)). Recipient mice were injected intraperitoneally with recombinant human growth hormone (20 microg/dose/day) or saline for the first 4 weeks after transplantation. These animals were followed for phenotypic and functional immune recovery.

RESULTS

Administration of human recombinant growth hormone improved the CD4(+) T-cell counts in peripheral blood on day +14 (44+/-14 vs 33+/-7/microL blood, p<0.05) and day +21 (281+/-109 vs 187+/-76/microL blood, p<0.01) compared with the saline control. These differences were no longer significant by day +28 despite continued growth hormone administration. Similar effects were also observed on CD8(+) T cells and B220(+) B cells. The improvements in peripheral T-cell counts were at least partially as a result of enhanced thymopoiesis because there was an increase in total thymocytes after treatment with growth hormone. T-cell-depleted bone marrow recipients treated with growth hormone rejected the third-party grafts faster than those treated with saline control (median survival time: 20 days vs 26 days, p<0.05).

CONCLUSIONS

These data demonstrated that recombinant human growth hormone can accelerate phenotypic and functional immune reconstitution following allogeneic T-cell-depleted bone marrow transplantation in mice.

Recombinant human growth hormone post-renal transplantation in children: a randomized controlled study of the NAPRTCS

BACKGROUND

Growth retardation persists in renal allograft recipients despite successful transplantation. The etiology is multi-factorial including the adverse effects of corticosteroids, suboptimal allograft function, and perturbations of the GH/GF axis. Recombinant human growth hormone (rhGH) has been effective in improving growth velocity; however, allograft dysfunction has been reported. Therefore, a randomized controlled study was undertaken.

METHODS

Sixty-eight growth retarded pediatric renal allograft recipients were enrolled in a one-year randomized controlled study to determine the efficacy and safety of rhGH. A protocol biopsy was performed prior to enrollment.

RESULTS

After one year, the delta SDS (standardized height) was +0.49 +/- 0.10 in the treatment group (N = 30) compared to -0.10 +/- 0.08 in the control group (N = 22; P < 0.001). During the first year, there were no rejection episodes in the treatment group and three in the control group. After the first year, when all recipients were receiving rhGH, there were three patients in the treatment group and two patients in the control group who experienced an acute rejection episode. Prior to enrollment, more than one acute rejection episode was predictive of a subsequent rejection following enrollment. There was no difference in adverse events between the two groups.

CONCLUSION

In conclusion, rhGH is effective in improving the growth velocity of pediatric renal allograft recipients and is not associated with an increase in adverse events.

[Recombinant human growth hormone in the treatment of growth retardation in children with decreased kidney function]

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[Critical evaluation of growth hormone treatment in children with chronic renal insufficiency]

Growth failure remains a major complication of chronic renal insufficiency in children, which greatly affects their quality of life. Based upon the data published in the literature it appears that growth hormone therapy improves growth in these children, with little secondary effects. However, some uncertainties persist concerning the safety and efficacy of this therapy, so that careful evaluations must continue.

Randomised controlled trial of recombinant human growth hormone in prepubertal and pubertal renal transplant recipients. British Association for Pediatric Nephrology

AIMS

To evaluate the efficacy (height velocity (HV), change in height standard deviation score (delta HSDS)), and safety (glomerular filtration rate (GFR), incidence of rejection, and calcium and glucose metabolism) of recombinant human growth hormone (rhGH) treatment after renal transplantation.

DESIGN

A two year randomised controlled trial.

SUBJECTS

Fifteen prepubertal and seven pubertal children: mean (SD) age, 13.0 (2.6) and 15.2 (2.4) years, respectively; mean (SD) GFR, 51 (30) and 48 (17) ml/min/1.73 m2, respectively. Six prepubertal and three pubertal children were controls during the first year; all received rhGH in the second year.

RESULTS

In the first year, mean (SE) HV and delta HSDS in the prepubertal treated group increased compared with controls: 8.1 (0.9) v 3.7 (0.6) cm/year and 0.6 (0.1) v -0.3 (0.2), respectively. In the pubertal treated group, mean (SE) HV and delta HSDS were also greater: 10.1 (0.6) v 3.9 (1.3) cm/year and 0.6 (0.1) v -0.1 (0.2), respectively. Comparing all treated and control children, there was no significant change in GFR: treated group, mean (SE) 9.9 (5.4) ml/min/1.73 m2 v control group, -1.6 (7.6) ml/min/1.73 m2. There were also no differences in the incidence of rejection in the first year: eight episodes in 13 patients v five episodes in nine patients, respectively. Phosphate, alkaline phosphatase (ALP), parathyroid hormone (PTH), and fasting insulin concentrations rose during the first year of treatment, but not thereafter. In the second year of treatment, HV remained above baseline.

CONCLUSION

Treatment with rhGH improves growth in prepubertal and pubertal children with renal transplants, with no significant change in GFR or the incidence of rejection. Phosphate, ALP, PTH, and insulin increased during the first year of treatment.

Treatment of peripubertal children after renal transplantation (RTX) with recombinant human growth hormone: auxological data and effects on insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 (IGFBP-3) during 24 months

OBJECTIVE

To evaluate growth and endocrine parameters in RTX children with GH treatment during 24 months.

SUBJECTS

18 children (13 boys), age 13.1 yr (8.0-16.6), bone age 10.1 yr (5.4-15.3). Patients were 2.8 yr (0.5-7.5) after RTX and had immunosuppressive therapy, prednisone 0.16 mg/kg/d (0.08-0.68).

METHODS

GH (4 IU/m2/day s.c.) was given and patients were seen every 3 months for evaluation of height, height velocity, bone age, and hormone parameters. Serum IGF-I was determined by RIA, IGFBP-3 by RIA and Western ligand blotting (WLB). Renal function and adverse effects (GFR, glucose tolerance, rejection episodes) were monitored.

RESULTS

Height (+1 SDS) and height velocity (+2.2 SDS) increased significantly during 24 months GH treatment, but delta BA/delta CA was 1.7 and 1.5 during the first and second treatment year, respectively, and all patients entered puberty during the treatment period. GFR decreased slightly during 2 yr (p = 0.048), two patients had chronic rejection and GH therapy was terminated in one patient because of glucose intolerance. The ratio IGF-I/IGFBP-3 rose during the first year (p = 0.002) indicating more bioavailable IGF-I. IGFBP-3 determined by WLB was decreased, but IGFBP-1, -2 and -4 were elevated as compared to a standard.

CONCLUSIONS

GH treatment increased height and growth rate in children after RTX. This may be due to significant changes in IGF-I and IGFBP-3 relationship. However, bone maturation was also accelerated thus diminishing height potential. From month 12 to 24 a continuous decrease of IGF-I was observed. There was a slight but significant deterioration of graft function. Adverse events that led to termination of GH therapy were observed in 3 of 18 patients.

Paediatric kidney transplantation

Renal transplantation is the optimal form of renal replacement therapy leading to substantial improvement in the quality of life. It has rapidly become the standard treatment for end-stage renal disease in children. However, despite impressive short-term results significant long-term problems remain unsolved. Because of the lack of effective treatment for chronic rejection and common recipient noncompliance, allograft half-life has not improved significantly during the last decade. A paediatric recipient is likely to need several retransplantations in adulthood. Moreover, the immunosuppressive drugs used today have potentially serious side-effects including nephrotoxicity and de novo malignancy. These are especially relevant for paediatric recipients who will continue to receive therapy for several decades. Most therapeutic protocols used for children are derived from those used for adults. However, the metabolic differences between an adult and a growing and developing paediatric transplant recipient are not always adequately appreciated before these new therapies are initiated. In the near future, we are likely to see new and more efficient drugs become available. It is important that we try to understand their properties in children and use them and our current arsenal on an individual basis aiming at optimal graft survival but also at avoiding unnecessary adverse effects.

Growth hormone treatment of children with chronic renal insufficiency, end-stage renal disease and following renal transplantation--update 1997

1. Long-term (> 5 years) hGH treatment in children with CRI produces sustained improvement in standardized height. 2. hGH treatment of infants (< 2 1/2 years of age) with CRI is as effective at improving growth velocity as in older children with CRI. 3. Once target height (50th percentile for midparental height) is reached the optimal approach is to pause hGH treatment and observe the patient. If standardized height declines significantly, hGH is effective when re-initiated. 4. Neither short-term nor long-term hGH treatment in children with CRI or in pediatric allograft recipients adversely impacts on carbohydrate tolerance; however, hyperinsulinemia develops which has not been associated with any clinical consequences to date. 5. The presence of renal osteodystrophy may blunt the impact of hGH and predispose to development of slipped capital femoral epiphysis and/or avascular necrosis in children with CRI. Pre-treatment radiologic evaluation and radiologic surveillance with clinical symptoms is indicated. 6. hGH is effective during the initial year of treatment; however the response may be blunted during subsequent years of treatment. The precise mechanism of the latter has not been delineated. 7. hGH has been shown to improve growth velocity in patients undergoing both peritoneal and hemodialysis; however, long-term data are lacking and the response may be less than that achieved in patients with CRI. 8. Growth velocity is uniformly improved in growth retarded pediatric renal allograft recipients receiving hGH. 9. Allograft dysfunction occurs following hGH treatment; however, the relationship to hGH treatment requires delineation. 10. The mechanism responsible for early allograft dysfunction which is usually reversible upon discontinuation of hGH is unknown. 11. Risk factors for the development of an acute rejection episode during the course of hGH treatment are > 1 prior rejection episode and the use of alternate day corticosteroid therapy. 12. The potential exists for an accelerated decline in allograft function following hGH treatment in recipients with chronic rejection. 13. The salutary effect of hGH in this patient population is probably related to increasing the bioavailability of ("free") IGF-I.

Growth hormone is not safe for children with renal transplants

Growth failure is an important problem in children with renal failure. Even after renal transplantation their growth rates may be lower than normal, and "catch-up" growth does not occur. Therefore there is great interest in giving growth hormone (GH) after transplantation. Clinical observations and theoretic considerations call into question whether GH after transplantation is safe. Studies have shown a more rapid than normal decline in renal function after the initiation of GH therapy. This result could be explained by the effects of GH on the immune response. Growth hormone is known to modulate (usually upregulate) the immune response and could be a reason for the increased loss of renal function caused by rejection. It could also be explained by the long-term effects of GH on the injured kidney. Experimental data (generally not in the transplantation model) suggest that exogenous GH given after renal injury or reduced renal mass leads to a more rapid development of glomerular sclerosis and reduced renal function. GH should not be administered to children after renal transplantation until all safety questions have been answered in prospective clinical trials.

A rational approach to short stature: focus on use and abuse of growth hormone

The abundant supply of recombinant growth hormone has raised interesting possibilities of several new applications. While supplementation of the missing hormone in patients with growth hormone deficiency is still the undisputed primary indication for its use, there is now convincing evidence of its usefulness in the therapy of short stature due to Turner syndrome and pre-transplant chronic renal failure in childhood. Numerous studies on patients with other causes of short stature have failed to show any significant benefit in final adult height. Social pressures notwithstanding, it is still premature to advocate the use of this expensive therapy for indications other than the three stated above especially since our understanding of potential long-term complications from such treatment is far from complete.

Current and potential therapeutic uses of growth hormone and insulin-like growth factor I

The accepted and potential uses of GH and IGF-I are summarized in Table 1. In general, the research on the therapeutic uses of IGF-I is at a much earlier state of development compared with GH The use of GH in the treatment of children with GH deficiency is well accepted, and its use in the treatment of short stature of renal failure also is widely accepted. The FDA has approved the use of GH in children with short stature caused by GH insufficiency and renal failure. The use of GH in patients with Turner syndrome has not been approved by the FDA, although it has been approved in several other countries. The use of GH for the treatment of adults with GH deficiency is approved in several countries but it is not approved in the Unites States. With the exception of the cases with GHIS, the use of IGF-I as a therapeutic agent cannot yet be regarded as of proven usefulness. The potential uses of GH and IGF-I are an area of active investigation and will continue to enlighten our understanding of human disease and disorders of growth.

Recombinant human growth hormone treatment. Its effect on renal allograft function and histology

Our objective was to investigate the effects of recombinant human growth hormone (rhGH) treatment on long-term renal allograft function and histopathology. RhGH is a potent therapy for poor growth after renal transplantation. However, rhGH has proinflammatory properties and may induce acute rejection or accelerate chronic rejection. Nine prepubertal rhGH-treated renal transplanted children and nine pair-matched controls were studied 18 (before the start of rhGH) and 36 months after transplantation (mean duration of rhGH-treatment 14 months). 51Cr-EDTA- and PAH-clearances were performed. A protocol renal biopsy was done at 36 months. Growth showed significant improvement during rhGH (P<0.01). One graft loss occurred in both groups. One acute rejection was seen in the control group. There was no difference in the rate pf change in 51Cr-EDTA-or PAH-clearance between the two groups. Histopathological findings were mostly mild. One new onset chronic rejection developed in both groups. Proximal tubular atrophy was more extensive in the rhGH-treated patients (P<0.05), but there was no uniform trend toward more severe findings. RhGH improved growth, and no significant differences were seen in allograft function or histopathology; however, larger trials controlled for pretreatment renal function and immunosuppression are needed.

Guidelines for the use of growth hormone in children with short stature. A report by the Drug and Therapeutics Committee of the Lawson Wilkins Pediatric Endocrine Society

On the basis of the information currently available, the only conditions in which GH therapy appears to be safe and effective in increasing adult height are GH deficiency and, likely, Turner syndrome. Therapy with GH also increases the growth velocity of children with CRI and may increase adult height, but no long-term data are available. Encouraging short-term results have been reported in patients with a few other conditions, such as patients with glucocorticoid-induced growth failure, renal transplantation, and Prader-Willi syndrome, but the data are limited and no long-term studies have been reported; in many other conditions the data are either inconclusive or discouraging. For children in these latter groups, GH therapy should be considered investigational and undertaken only as part of ethically sound, controlled clinical trials. Knowledge concerning the conditions in which GH is safe and effective is a prerequisite to making rational decisions concerning its use. However, in deciding whether therapy is warranted in an individual child, one must consider other important factors. The age and emotional maturity of the child, the family structure and dynamics, and even financial considerations may, in some cases, outweigh the presence of a GH-responsive condition. Likewise, the child's and the family's views about "short" stature and the likely benefits of therapy must be considered. Ultimately, a decision concerning the appropriateness of GH therapy must be individualized and based on a realistic assessment of its impact on the quality of life of the child and future adult.