Growth promoting effects of growth hormone and IGF-I are additive in experimental uremia

Exogenous growth hormone (GH) stimulates the endogenous production of IGF-I and improves growth in uremia. We investigated whether exogenous IGF-I is also able to improve uremic growth failure in rats and whether the growth promoting effects of GH and IGF-I are additive. In female 150 g uremic (subtotal nephrectomy, NX) Sprague-Dawley rats, both rhGH in doses from 2 X 1.25 to 2 X 10 IU/kg bid s.c. and rhIGF-I in doses from 2 X 0.5 to 2 X 4.0 mg/kg bid s.c. caused a dose-dependent increase in weight gain and length gain. However, endogenous production of GH was suppressed by both agents. Peptide hormone treatment did not affect cumulative food intake, but significantly increased food efficiency ratio (weight gain/food intake). Concomitant s.c. treatment with maximally effective doses of rhGH (12 X 5 IU/kg bid) and of rhIGF-I (2 X 2 mg/kg bid) resulted in additive growth promoting effects in NX and pair-fed control (CO) animals during the observation period of 12 days. Cumulative length gain was 3.2 +/- 0.5 cm in solvent-treated NX-animals, 4.1 +/- 0.5 cm with rhGH (+ 28% above solvent), 4.2 +/- 0.6 cm with rhIGF-I (+ 31%) and 4.9 +/- 0.5 cm with both peptides (+ 53%). The food efficiency ratio was 0.16 +/- 0.05 in solvent NX, 0.33 +/- 0.04 with rhGH (+ 106% above solvent), 0.23 +/- 0.02 with rhIGF-I (+ 44%), and 0.38 +/- 0.02 with both peptides (+ 138%). Histomorphometric analysis and measurements of length gain by fluorescence microscopy in the upper tibial metaphysis confirmed the growth promoting effects of both peptide hormones. The serum concentrations of IGF binding protein (BP)-4 (Western ligand blotting analysis) and of IGFBP-2 (immunoblot) were increased in uremic animals whereas IGFBP-3 was unchanged. Treatment with IGF-I and/or rhGH increased serum concentration of IGF-I but did not change the IGFBP pattern. rhIGF-I lowered blood glucose levels within one to two hours after injection. The effect was most pronounced during the first treatment day and declined thereafter. Concomitant treatment with rhGH attenuated the glucose lowering effect of rhIGF-I (glucose serum concentration at day one: 120 +/- 11 mg% in solvent NX, 50 +/- 21 mg% with rhIGF-I, 80 +/- 24 mg% with both peptides). It is concluded that: (i) IGF-I is able to stimulate growth in NX animals but suppresses endogenous GH production in the long run; (ii) the concomitant treatment with IGF-I and GH has additive effects on growth; and (iii) concomitant treatment with rhGH prevents hypoglycemia that is noted with rhIGF-I alone.

Growth hormone as a new treatment modality for short children with chronic renal failure. The German Study Group for Growth Hormone Treatment in Chronic Renal Failure

Recombinant human growth hormone (rhGH) has become a new treatment modality for short children with chronic renal failure (CRF) and after renal transplantation. The rationale for high-dose rhGH treatment is the insensitivity of the uremic organism to GH. As the insensitivity to GH is expressed more in end-stage renal failure than in earlier stages of CRF, patients on dialysis respond less to rhGH. In transplanted children, rhGH can counterbalance the growth-depressing effects of corticosteroids. In prepubertal children, rhGH improves the height standard deviation score by a mean of +2 within 5 years. The effect of rhGH treatment on final height remains to be studied.

Transplantation Report. 2: Pre-emptive renal transplantation in adults aged over 15 years. The EDTA-ERA Registry. European Dialysis and Transplant Association-European Renal Association

Between 1985 to 1992, 2545 renal transplantation (RTx) were performed as pre-emptive grafts in adults. This procedure represented 7.2% of first RTx for patients starting first renal replacement therapy (RRT) during this period, 6.1% of RTx performed in 1992 and 5.6% of all RTx ever performed and reported to the EDTA Registry. The procedure is more frequent in cases of live donor grafts, representing one third of pre-emptive RTx. Both 5 year patient and graft survivals are unaffected by dialysis duration prior to the first RTx: none in pre-emptive, < 1 years, 1-5 years or > 5 years. In our personal view, this procedure should be developed.

Multifactorial control of the elimination kinetics of unbound (free) growth hormone (GH) in the human: regulation by age, adiposity, renal function, and steady state concentrations of GH in plasma

To evaluate the principal determinants of the MCR and plasma t1/2 of unbound (free) GH in man, we performed steady state infusions of 3 doses of recombinant human GH during pharmacological suppression (iv octreotide) of endogenous GH secretion in 24 healthy adults and 12 patients (6 adults and 6 children) with chronic renal failure (CRF). Free plasma GH was calculated from total plasma GH (measured by immunoradiometric assay) and GH-binding protein activity (radioligand assay). The MCR of free GH was determined from free plasma GH and the rate of recombinant human GH infusion. The t1/2 of free plasma GH, and the concentration and the in vivo dissociation constant (Kd) of GH-binding protein (GHBP) were estimated by dynamic modeling of the postinfusion total plasma GH concentration decay curves. The MCR of free GH decreased and the plasma GH t1/2 increased significantly with increasing plasma GH concentrations. The MCR of free GH over its physiological concentration range was positively correlated with the body mass index as a measure of relative obesity and negatively related to age, but only at supraphysiological GH concentrations. In the adult patients with CRF, the MCR of free GH was decreased at each infusion rate by 25-38%, and the t1/2 was increased by 80-170%. Children with CRF showed a significantly lower MCR and higher t1/2 of plasma free GH than adult patients. Modeling and direct measurements of the off-rate of GH from its high affinity GHBP indicated normal dissociation rate constants but decreased molar concentrations of the GHBP in uremic plasma. We conclude that the rate of elimination of free GH from plasma in man is controlled by 1) plasma total free GH concentrations, 2) relative obesity, and 3) renal function within the physiological GH concentration range, whereas 4) age is a negative predictor of MCR only at supraphysiological GH concentrations.

Assessment of total body water in paediatric patients on dialysis

BACKGROUND

Various anthropometric techniques are used to assess total body water in children on dialysis; however, their predictive accuracy and precision has not been validated.

METHODS

We compared total body water measurements obtained by deuterium oxide (D2O) dilution with predictions of total body water from (1) height and weight, (2) skinfold measurements, and (3) bioelectrical impedance analysis, using previously published formulae for healthy children. Measurements were performed in 14 patients on peritoneal and in nine patients on haemodialysis, aged 4-22 years.

RESULTS

In the total population of dialysed patients, weight was the strongest single predictor of total body water (R2 = 0.93), followed by the resistance index (RI = height2/impedance; R2 = 0.85) and height (R2 = 0.93). A prediction formula based on height and weight predicted total body water with a residual mean square error (RMSE) of 1.97 1 (coefficient of variation (CV) = 10.0%) and with a systematic overestimation of true total body water by 0.4%. A prediction equation based on skinfold measurements yielded a total body water estimate with an RMSE of 2.15 1 (CV = 10.5%) and overpredicted true total body water by an average of 2.2%. Using three published prediction equations incorporating RI, RMSEs of 2.78 1 (CV = 14.1%) with a mean under- or overestimation of true total body water by 6.9, 7.1, and 0.8% respectively, were achieved. The prediction of total body water was optimized by linear combinations of RI or the log-transformed sum of four skinfolds (logsum) with weight by the following equations: total body water (1) = 9.97 - 3.13 x logsum (1) +0.59 x weight (kg) (R2 = 0.951; RMSE = 1.67 1; CV = 8.17%). total body water (1) = 1.99 + 0.144 x RI (Ohm/cm2) (2) + 0.40 x weight (kg) (R2 = 0.949; RMSE = 1.67 1; CV = 8.53%). The fit of these prediction formulae, which were derived from the total population, did not differ significantly between haemo- and peritoneal dialysis patients or between boys and girls.

CONCLUSIONS

Both skinfold measurements and bioelectrical impedance analysis can be used to improve the height- and weight-based prediction of total body water in children on dialysis.

Serum insulin-like growth factors (IGFs) and IGF binding proteins 1, 2, and 3 in children with chronic renal failure: relationship to height and glomerular filtration rate. The European Study Group for Nutritional Treatment of Chronic Renal Failure in Childhood

Serum levels of insulin-like growth factor I (IGF-I), IGF-II, and IGF binding protein 1 (IGFBP-1), IGFBP-2, and IGFBP-3 were measured in 94 children with chronic renal failure (CRF). The results were compared with their respective age-dependent normal ranges, and the relationship with height and residual glomerular filtration rate (GFR) was examined. Each IGF and IGFBP was quantified by specific RIA. Serum IGF-I and IGF-II levels were in the normal range throughout their entire childhood in the vast majority of cases. The mean age-related IGF-I (0.07 +/- 0.14 SD score) and IGF-II levels (0.06 +/- 0.11 SD) were similar. Age-related IGF-II but not IGF-I levels showed a weak inverse linear correlation with residual GFRs (r = -0.24, P < 0.02). Mean age-related IGFBP-1 serum levels (1.04 +/- 0.09 SD) were slightly elevated, whereas mean age-related serum IGFBP-2 levels (3.25 +/- 0.20 SD) and serum IGFBP-3 levels (2.61 +/- 0.12 SD) were markedly elevated. Significant inverse correlations were found between GFRs and age-related IGFBP-1 (r = -0.42, P < 0.001), IG-FBP-2 (r = -0.56, P < 0.001), and IGFBP-3 (r = -0.28, P < 0.005), but the increase in IGFBP-2 with declining GFR was relatively more pronounced than the respective increase in IGFBP-1 and IGFBP-3. The correlation between age-related IGF-I and relative height in prepubertal children with CRF (n = 54, r = 0.43, P < 0.001) was lower than in prepubertal controls (n = 68, r = 0.67, P < 0.001), and the slope of the regression line was significantly less steep, indicating that the normal relationship between IGF-I and height is disturbed in CRF. The normal relationship between IGFBP-3 and height was disrupted in CRF. Forward stepwise regression analysis revealed that height in CRF is correlated with IGF-I and inversely correlated with IGFBP-2. We conclude that the imbalance between normal IGFs and excessive IGFBP serum levels in CRF plays a pathogenic role in the growth failure of these children.

Disproportionate growth following long-term growth hormone treatment in short children with X-linked hypophosphataemia

Three short prepubertal children with X-linked hypophosphataemia were treated with 1 IU recombinant human growth hormone (rhGH)/kg per week sc in addition to calcitriol and phosphate supplementation over a period of 3 years. Improvement of height standard deviation score (SDS) ranged from 1.0-1.7 SD based on an increase in sitting height of 1.5-2.9 SD, whereas subischial leg length improved only slightly by 0.3-0.9 SD. In all three patients, renal phosphate threshold concentration increased slightly and transient hyperparathyroidism was noted.

CONCLUSION

Treatment of stunted children with X-linked hypophosphataemia is effective in improving growth velocity, but appears to aggravate the pre-existent disproportionate stature of such children.

Calbindin-D28K and -D9K and 1,25(OH)2 vitamin D3 receptor immunolocalization and mineralization induction in long-term primary cultures of rat epiphyseal chondrocytes

Rat epiphyseal plat chondrocytes were grown on glass slides, as nonadhering monolayer cultures for up to 6 weeks. Chondrocyte growth, differentiation and maturation, matrix formation and mineralization, and the temporospatial distribution of the vitamin D-dependent calcium-binding proteins, calbindin-D9K and -D28K, and the 1,25(OH)2D3 receptor (VDR), were all monitored. Chondrocytes became confluent in 2.5 weeks, differentiated to acquire a chondrocyte (polygonal) morphology, produced extracellular matrix, and finally formed a true monolayer mineralizing cartilaginous tissue, with all the stages of chondrocyte development within a single culture. beta-Glycerophosphate promoted initial matrix mineralization in 4 weeks and accelerated cell differentiation. High nominal calcium and ascorbic acid were needed for abundant matrix formation. VDR occurred at all differentiation stages, in the nuclei and nucleoli and in the cytoplasm. Calbindin-D28K and -D9K were not coexpressed. Calbindin-D28K was found in prechondroblasts, chondroblasts, and in newly differentiated chondrocytes. It was cytoplasmic in prechondroblasts and subsequently also in the perinuclear region and in nuclei, suggesting migration to the nuclear chromatin. Calbindin-D28K was nuclear only in newly differentiated chondrocytes in vitro and was not found in mature chondrocytes. In contrast, calbindin-D9K was present in the cytoplasm of mature and hypertrophic chondrocytes only. It was first in the cell body and eventually migrated within and to the far end of long cell processes with a decreasing cytoplasmic concentration showed by decreased immunostaining intensity, and ultimately hypertrophy of chondrocytes in culture. These in vitro patterns of calbindins-D and VDR accurately reflect their in vivo distributions. The genomic action of vitamin D, in vitro, resulted in the synthesis of nuclear VDR and calbindins-D.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantification of urinary insulin-like growth factors (IGFs) and IGF binding protein 3 in healthy volunteers before and after stimulation with recombinant human growth hormone

We examined excretion of urinary insulin-like growth factors I and II (IGF-I and IGF-II) and their major binding protein IGFBP-3 in comparison to their respective serum concentration in nine healthy female volunteers (median age 25 years, range 22-27) under baseline conditions and after stimulation with recombinant human growth hormone (rhGH), 4.5 IU twice daily subcutaneously for a period of 3 days. The IGFs were measured in unconcentrated urine by use of recently developed, highly sensitive radioimmunoassays. The IGFBP-3 was measured by a specific radioimmunoassay. The mean (+/- SD) urinary concentrations of IGF-I (0.08 +/- 0.07 micrograms/l), IGF-II (1.02 +/- 0.47 micrograms/l) and IGFBP-3 (19.1 +/- 6.9 micrograms/l) were two to three orders of magnitude lower than in serum. The ratio of IGF-II over IGF-I concentration in urine (13:1) was five times higher than in serum (2.5:1), and the ratio of IGFBP-3 over the sum of IGF-I and IGF-II in urine (17:1) was four times higher than in serum (4:1). Urinary excretion was 63.3 +/- 46.6 ng.m-2.24h-1 for IGF-I, 1002 +/- 598 ng.m-2.24h-1 for IGF-II and 18039 +/- 4983 ng.m-2.24h-1 for IGFBP-3. Using fast protein liquid exclusion chromatography, only immunoreactive IGFBP-3 components of less than 60 kD were detected in urine, with a major peak at 20 kD. Urinary IGFBP-3 excretion correlated with serum IGFBP-3 (r = 0.61, p < 0.01) and the glomerular filtration rate (r = 0.56, p < 0.05) measured by steady-state inulin infusion clearances.(ABSTRACT TRUNCATED AT 250 WORDS)

Deconvolution analysis of spontaneous nocturnal growth hormone secretion in prepubertal children with preterminal chronic renal failure and with end-stage renal disease

We sought to determine whether elevated circulating growth hormone (GH) concentrations in uremic prepubertal children are due to an increase in GH secretory activity by the pituitary gland or a decrease in the metabolic clearance of GH consequent to reduced GFR. Deconvolution analysis was applied to the nighttime plasma GH profiles of 1) 11 children with preterminal chronic renal failure, 2) 12 children with end-stage renal disease (ESRD), and 3) a control group of matched children with idiopathic short stature (n = 12). Mean (+/- SEM) half-life of endogenous GH in children with ESRD (27.5 +/- 2.7 min) and preterminal chronic renal failure (23.1 +/- 2.1 min) was significantly higher than in controls (14.8 +/- 1.6 min; p < 0.001). GH half-life correlated inversely with GFR (r = -0.65, p < 0.001). The number of GH secretory bursts/10 h in ESRD (8.1 +/- 0.4) was amplified compared with preterminal chronic renal failure (6.4 +/- 0.5) and with controls (5.9 +/- 0.4; p < 0.005). GH production rate varied over a broad range in the three groups: It was highest in ESRD (202 +/- 56.6 microgm/L/10 h; range 36-683), mainly as a result of an increased number of GH secretory bursts, and not statistically different in preterminal chronic renal failure (66.2 +/- 11.4 microgm/L/10 h; range 25-168) and in controls (129 +/- 27.7 microgm/L/10 h; range 39-392). Increased GH half-life, in concert with an increased GH production in some individuals with ESRD, leads to a 2.5-fold increase in the mean plasma GH concentration in ESRD compared with the two other groups (p < 0.005) [corrected].(ABSTRACT TRUNCATED AT 250 WORDS)

Vitamin D therapy in patients receiving dialysis

Secondary hyperparathyroidism is found in a large proportion, but not all patients on dialysis. Calcitriol controls moderate hyperparathyroidism in most patients but only in a proportion of those with advanced hyperparathyroidism. Patients with nodular parathyroid hyperplasia respond less frequently, presumably because of monoclonal growth and diminished calcitriol-receptor expression by parathyroid cells. In patients with nodular parathyroid hyperplasia, parathyroidectomy is an important alternative to calcitriol treatment. A priori reasoning indicates that prophylactic administration of calcitriol (to prevent parathyroid hyperplasia) is a reasonable option, but currently no controlled evidence for long-term efficacy of this approach without side effects is available. Intermittent administration of calcitriol by intravenous or oral routes is effective and, at least in experimental studies, superior to continuous calcitriol. However, in clinical comparisons, no superiority of intravenous versus oral or daily versus intermittent calcitriol has been documented. Calcitriol treatment must be closely supervised to prevent hypercalcemia, hyperphosphatemia, and excessive suppression of parathyroid hormone. Because of an altered dose response relationship, parathyroid hormone levels should not be completely normalized so as to prevent low bone turnover (adynamic bone lesion).

Insulin-like growth factors (IGF) and IGF binding proteins in children with chronic renal failure

The pathomechanism of growth retardation and catabolism in children with chronic renal failure (CRF) is multifactorial. Recent evidence indicates that in particular disturbances of the somatotropic hormone axis play an important pathogenic role. In preterminal CRF serum insulin-like growth factor (IGF)-I and IGF-II levels are normal, 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 growth hormone levels in ESRD, these serum IGF-I levels appear as inadequately low. Indeed, there is both clinical and experimental evidence for a decreased hepatic IGF-I production rate in CRF. This hepatic insensitivity to the action of GH is partially owing to a reduced GH receptor expression. The action and metabolism of IGFs are modulated by specific high-affinity IGF binding proteins (IGFBPs), which bind approximately 99% of circulating IGF. IGFBP-1, IGFBP-2, and low molecular weight IGFBP-3 fragments are increased in CRF serum in relation to the degree of renal dysfunction. Both decreased renal filtration, in particular of low molecular weight IGFBP-3 fragments, and increased hepatic production of IGFBP-1 and -2 contribute to high IGFBP serum levels. Experimental and clinical evidence suggests that these excessive high-affinity IGFBPs in CRF serum inhibit IGF action on target tissues by competition with the type 1 IGF receptor for IGF binding.

Synergistic effects of parathyroid hormone and 1,25-dihydroxyvitamin D3 on proliferation and vitamin D receptor expression of rat growth cartilage cells

We investigated possible interaction of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] and PTH on: 1) proliferation (monolayer culture) and colony formation (agarose stabilized suspension cultures); 2) expression of 1,25-(OH)2D3 receptor (VDR); and 3) cAMP response to PTH, using primary cultures of chondrocytes from rat tibia proximal epiphysis. 1 alpha,25-(OH)2D3 stereospecifically stimulated DNA synthesis, cell counts, and colony formation at low concentration (10(-12) M). Within 6 h bovine PTH (bPTH)(1-34), human PTH (hPTH)(28-48) (10(-10) M), (Bu)2cAMP (1-2 mM), and 12-O-tetradecanoyl-13-acetate (10(-8) M) increased [3H]thymidine incorporation in the absence and presence of 1,25-(OH)2D3. Both PTH fragments also stimulated chondrocyte growth and colony formation in a Ca-dependent fashion. Prolonged exposure to bPTH(1-34) or hPTH(28-48) did not affect baseline DNA synthesis but increased the stimulatory effect of 1,25-(OH)2D3. This increase was inhibited in the presence of H7 (inhibition of PKC) or the monoclonal hPTH(1-38) antibody A1-70. In subconfluent chondrocyte cultures VDR was up-regulated by bPTH(1-34) and hPTH(28-48) (10(-10) M) or activators of protein kinase C (PKC), but not by (Bu)2cAMP. It was blocked by cycloheximide and actinomycin D and persisted in the presence of Ca-channel blockers. Inhibition of PKC by H7 also blocked the effect of bPTH(1-34) on VDR. The cAMP response to bPTH(1-34) was not affected by 1,25-(OH)2D3. We conclude that: 1) DNA synthesis, cell proliferation, and colony formation in chondrocyte monolayer or suspension cultures is increased by aminoterminal and midregional PTH fragments and by cAMP analogs in a Ca- dependent fashion; 2) bPTH(1-34) and hPTH(28-48) up-regulate VDR by cAMP-independent, PKC-dependent steps requiring transcriptional and translational processes; both PTH fragments also amplify the effect of 1,25-(OH)2D3 on DNA synthesis; and 3) no difference is found between the bPTH(1-34) and hPTH(28-48) fragments with respect to chondrocyte proliferation and VDR up-regulation, although the two differ with respect to stimulation of cAMP production.

[Kidney transplantation in children]

Renal transplantation has become an established form of therapy for children with endstage renal disease. Evaluation and elimination of potential risk factors, standardization of operative technique and better immunosuppressive regimens improved the outcome in paediatric patients. A shortage or organs means that transplantations cannot always be offered to children for whom it would be the treatment of choice. Kidney donation by living relatives opens up the potential for optimal rehabilitation of patients in the paediatric age group.

The use of recombinant human growth hormone in short children with chronic renal failure

Regulation of the somatotropic axis is altered in chronic renal failure (CRF) resulting in a secondary syndrome of growth hormone (GH) insensitivity. Secretion of growth hormone estimated by deconvolution analysis is low normal in prepubertal patients and reduced in late pubertal children with CRF. Basal and integrated GH serum concentration measured by RIA is increased due to reduced renal metabolic clearance, whereas the fractional urinary excretion is increased due to damage of renal tubular cells. GH receptor mRNA is decreased (rat) and the serum concentration of GH binding protein (BP) activity is low (man). Insulin-like growth factor (IGF)-1 production rate is reduced, whereas serum concentrations of IGFBPs are increased secondary to reduced renal metabolic clearance. This results in a reduction of free, active IGF-1. Treatment with GH induces a rise in serum IGF-1 concentration and normalizes IGF bioactivity. Clinical studies in prepubertal children demonstrated a dramatic rise in height velocity during the first treatment year and to a lesser extent during the following years. In children on conservative treatment prior to dialysis, mean height SDS improved by 1.5 within two years and by 2.0 within four years. Patients with renal allografts responded in a similar way. Age and pretreatment height velocity SDS are confounding variables for the response to GH. Renal function seems not be altered by recombinant human (rh) GH in patients with CRF, and the number of renal allograft rejection crises seems not to be substantially increased under rhGH treatment in allograft recipients.

Growth response to recombinant human growth hormone in short prepubertal children with chronic renal failure with or without dialysis. The European/Australian Study Group

The growth-promoting effect of recombinant human growth hormone (GH) in children with chronic renal failure was assessed in eight clinical trials. A total of 103 prepubertal children participated in the trials, 34 of whom were undergoing dialysis. The children were treated with GH, 30 IU/m2/week (approximately 1 IU/kg/week), for up to 2 years, and various growth parameters, bone age and renal function were assessed before and during treatment. In all trials, the children showed clear catch-up growth and an improved height SDS after treatment with GH, although the increase in height was less in dialysis patients than in those not receiving dialysis. GH maintained its growth-promoting effect during the second year of treatment; the effect, however, was less marked than during the first year of treatment. Bone age appeared to advance in parallel with chronological age. Median serum creatinine increased from 204 mumol/l to 230 and 262 mumol/l after 12 and 24 months of treatment, respectively, due to increased muscle mass and/or progression of the underlying renal disease. The loss of estimated glomerular filtration rate/year was not different before and during GH treatment.

Reduced hepatic growth hormone (GH) receptor gene expression and increased plasma GH binding protein in experimental uremia

In uremia, reduced longitudinal growth and decreased hepatic insulin-like growth factor-I (IGF-I) secretion despite elevated GH serum levels point to an insensitivity to the action of GH. The molecular basis that accounts for this insensitivity could comprise decreased GH receptor expression in the target organs for GH or binding of GH in the circulation to substances that compete with the receptor. To address this hypothesis, the abundance of hepatic GH receptor mRNA was measured by solution hybridization RNase protection assay in uremic female Sprague-Dawley rats, following two-stage 5/6 nephrectomy, and in pair-fed and in ad libitum-fed sham-operated controls; rat GH binding protein (GHBP) plasma concentration was measured by a sensitive direct RIA. Uremia was associated with a 50% decrease of hepatic GH receptor expression compared to pair-fed controls, which themselves showed a 25% reduction of hepatic GH receptor mRNA abundance when compared to ad libitum-fed controls. Plasma GHBP levels in uremia were markedly higher than in both control groups. Treatment with recombinant human GH (rhGH) (10 IU/kg body wt per day s.c. for 10 days) led to a comparable induction of IGF-I plasma levels and weight gain in uremia and pair-fed controls, indicating that the insensitivity to GH in uremia can be overcome by large rhGH doses. Subcutaneous rhGH injections did not significantly alter the hepatic GH receptor transcript abundance or plasma GHBP levels in any of the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolic clearance of recombinant human growth hormone in health and chronic renal failure

Despite the increasing therapeutic use of recombinant human growth hormone (rhGH), its metabolic clearance has not been investigated in detail. To evaluate the kinetics of rhGH as a possible function of GH plasma concentration and glomerular filtration rate (GFR), we investigated the steady state metabolic clearance rate (MCR), disappearance half-life, and apparent volume of distribution of rhGH at low and high physiological as well as supraphysiological plasma GH levels during pharmacological suppression of endogenous GH secretion in human subjects with normal and reduced renal function. GH in plasma and urine was determined by an immunoradiometric assay, and GFR by inulin clearance. In all subjects MCR decreased and plasma half-life increased with increasing plasma GH concentrations (P < 0.001). MCR of rhGH was approximately half in patients with chronic renal failure at each GH level and plasma half-life was increased by 25-50%. Allowing for the linear dependence of MCR on GFR and assuming single-compartment distribution, the estimated renal fraction of total MCR was 25-53 and 4-15% in controls and patients, respectively. Saturation of extrarenal disposal of GH was suggested by an inverse hyperbolic relationship between extrarenal MCR and plasma GH concentrations in all subjects. Fractional GH excretion was up to 1,000-fold higher in patients than in controls. We conclude that MCR of hGH is a function of plasma GH concentrations and GFR. Extrarenal elimination is saturable in the upper physiological range of GH concentrations, whereas renal MCR is independent of plasma GH levels. The kidney handles GH like a microprotein involving glomerular filtration, tubular reabsorption, and urinary excretion.

Outcome and prognostic determinants in the hemolytic uremic syndrome of children

The late outcome in 89 children with the hemolytic-uremic syndrome (HUS) observed from 1971 to 1988 was analyzed up to 17 years after onset in relationship to various clinical and pathologic features at the onset of the disease. In the first 3 months after onset (acute phase) 69% of all children needed dialysis therapy. Fifteen children died, 9 during the acute phase and 6 subsequently. All surviving patients except 7 were reexamined and divided into five prognostic categories: recovery, residual renal symptoms with normal kidney function, moderate renal insufficiency, preterminal chronic renal failure (CRF) and end-stage renal disease (ESRD). The rate of recovery calculated by the life table method increased from 35% after 10 years in 1971-1979 to 68% in 1980-1988 (p < 0.001); it was lower in infants than in older children (44 vs. 63%; nonsignificant). Children with atypical HUS experienced more often preterminal CRF, ESRD or death than those with a typical (postenteropathic) form (33 vs. 17%; p < 0.05). If oliguria lasted < 7 days, 74% of patients recovered after 10 years versus 13% in the case of oliguria > 14 days or anuria > 7 days (p < 0.0005). The rate of recovery was also significantly smaller with the duration of dialysis treatment > 7 days, central nervous system involvement and requirement for antihypertensive therapy. In the entire series 7 patients developed preterminal CRF and 5 ESRD. Of 27 cases serially followed for 5-10 years after onset, a stable course was noted in 16, a subsequent improvement in 8 and deterioration in 3 leading to ESRD in 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of rhGH and rhIGF-1 on renal growth and morphology

It is known that in rodents recombinant human growth hormone (rhGH) and recombinant human insulin-like growth factor (rhIGF-1) increase renal mass. It is uncertain, however, whether renal mass increases in proportion to body growth, or whether renal growth is stimulated selectively. In 120 to 150 g female Sprague-Dawley rats, we measured the effects of rhGH and rhIGF-1 and their combination by the following parameters: kidney weight/body weight ratio, DNA/protein ratio, mRNA of GH receptor and of IGF-1, mitosis index and PCNA (by immunohistology), zonal architecture and glomerular diameter by micromorphometry. Both rhGH and rhIGF-1 dose-dependently increased renal weight and body weight over vehicle treated controls. With rhGH, liver dry weight/body weight ratio increased, but kidney dry weight/body weight ratio remained unchanged (0.99 +/- 0.06 x 10(-3) vs. 1.02 +/- 0.07 in vehicle controls). In contrast, a significant increase of kidney dry weight/body weight ratio was seen in rats treated with rhIGF-1 (1.3 +/- 0.21 x 10(-3). Addition of high doses of rhGH to high doses of rhIGF-1 caused no further increase of the ratio despite a significant further increase of body weight. rhGH increased the abundance of renal GH receptor mRNA (0.46 +/- 0.32 amol/microgram DNA vs. 0.08 +/- 0.07 in controls) and of IGF-1 mRNA (1.35 +/- 0.5 pg/micrograms DNA vs. 0.35 +/- 0.17), whereas no change was seen with IGF-1 treatment. rhGH and rhIGF-1 increased kidney DNA/protein ratio, mitoses and PCNA expression in various renal structures.(ABSTRACT TRUNCATED AT 250 WORDS)

Predictors of growth response to rhGH in short children before and after renal transplantation. German Study Group for Growth Hormone Treatment in Chronic Renal Failure

Many children with chronic renal failure (CRF) present with a reduced height and a reduced height velocity resulting in diminished final height irrespective of renal replacement therapy. Recombinant human growth hormone (rhGH) has become a new treatment modality for short renal patients, and the response to rhGH varies widely. In order to identify possible predictors of response to rhGH, the influence of sex, chronological age, bone age, pubertal status, height and height velocity at basal, target height, treatment modality for CRF, residual glomerular filtration rate (GFR), and steroid treatment was analyzed by single and multiple regression analysis in 49 children prior to and after renal transplantation. During the first treatment year with 28 to 30 IU rhGH/m2/week given by daily s.c. injections, height velocity was highest in patients on conservative treatment and lowest in patients on dialysis. Height velocity expressed in cm/year was inversely correlated with age (r = -0.63; P < 0.0001) and positively correlated with pretreatment height velocity (r = 0.65; P < 0.0001). The increment in height velocity SDS (chronological age) was significantly negatively correlated with the pretreatment height velocity SDS (chronological age) (r = -0.58, P < 0.001), indicating that at any given age the slowest growing children tended to respond best to rhGH treatment. It is concluded that the response to rhGH is significantly influenced by age, pretreatment height velocity, and treatment modality for CRF, whereas the influence of other variables is less important.

Evaluation of protein intake by dietary diaries and urea-N excretion in children with chronic renal failure. European Study Group for Nutritional Treatment of Chronic Renal Failure in Childhood

In 1988 a European multicentre, randomized trial was started in order to analyse the influence of protein intake on the progression of chronic renal failure in children. Compliance to the dietary prescriptions, i.e. protein intake, was checked by written dietary diaries and in addition by urinary urea-N excretion. This provided a unique chance to compare both methods in non-hospitalized children. Of a total of 200 patients 123 were selected, in whom at least 4 consecutive dietary diaries plus 4 completely collected 24-hour urine samples were available. Whereas urea-N excretion and simultaneously recorded protein intake did not correlate well, mean urinary urea-N excretion and mean protein intake of at least 4 observations in each patient correlated highly (r = 0.803, p = 0.0001). The difference between protein-N intake and urea-N excretion was not a constant amount of 0.031 g/kg/day as proposed by Maroni et al. [1985] but figured at 0.085 +/- 0.061 g/kg/day and was highly correlated to protein intake (r = 0.839, p = 0.0001). The correlation of protein intake and urea-N excretion was best described by the formula: protein-intake (g/kg/day) = (urea-N excretion [g/kg/day]x 15.39) -0.8 or protein intake (g/kg/day) = urea-N excretion (g/kg/day) x 9.5. Maroni's formula underestimated the high protein intake of young children. In only a few patients dietary diaries severely underestimated protein intake as compared to calculation by urea-N excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Intermittent and continuous exposure to 1,25(OH)2D3 have different effects on growth plate chondrocytes in vitro

Intermittent 1,25(OH)2D3 administration is widely used to suppress parathyroid glands in secondary (renal) hyperparathyroidism. It is unknown whether the effects of continuous and intermittent 1,25(OH)2D3 differ on vitamin D target organs other than parathyroids. Using primary cultures of rat chondrocytes (tibia) we compared the effects of continuous versus intermittent exposure to physiologic concentrations of 1 alpha,25(OH)2D3 on proliferation (radiothymidine incorporation), cell count, protein synthesis ([3H]-leucine incorporation), alkaline phosphatase activity (as a marker of differentiation) and 1 alpha,25(OH)2D3 receptor (VDR) regulation. Cells were synchronized and then exposed for variable periods to a medium containing 10% delipidated FCS and 10(-8) M to 10(-12) M 1 alpha,25(OH)2D3 (or 1 beta,25(OH)2D3 as specificity control). Intermittent (8 hr exposure every 48 hr) as well as continuous (sham washing) administration of 1 alpha,25(OH)2D3 had a biphasic effect on proliferation, that is, stimulation at low (10(-12) M) and inhibition at high (10(-8) M) concentrations. At 10(-12) M intermittent 1 alpha,25(OH)2D3 yielded higher cell counts than continuous 1,25(OH)2D3. This was seen in the log phase, which was day 3 (continuous 141 +/- 2.3% of solvent control; intermittent 185 +/- 2.0%) and in the plateau phase of growth, which was day 6 (128 +/- 2.6 vs. 169 +/- 2.7% of solvent control). Dependence on extracellular Ca is suggested by the effects of varying nominal Ca concentrations in the medium and of Ca channel blockers. Even two hours of exposure to 1 alpha,25(OH)2D3 (10(-12) M) yielded maximal activation of AP during postincubation.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemotherapy with cytosine arabinoside in a child with Burkitt's lymphoma on maintenance hemodialysis and hemofiltration

A case of Burkitt's lymphoma (stage IV) in an 8-year-old boy with end-stage renal failure due to hemolytic uremic syndrome is reported. The boy was treated by maintenance hemodialysis (HD) and hemofiltration (HF). During chemotherapy treatment with continuous cytosine arabinoside (Ara-C) infusion (100 mg/m2/d) for 7 days, concentrations of Ara-C and its metabolite uracil arabinoside (Ara-U) were measured in blood, dialysate, and filtrate. Ara-C levels were always below 200 ng/ml and were only qualitatively detectable in blood, dialysate, and filtrate. Ara-U levels were higher than 200 ng/ml after 18 h treatment and were measured quantitatively. Ara-U clearance during 3 h HD was 92 ml/min and the calculated mass removal 14.7 mg/3 h. In contrast, the Ara-U clearance during 3 h HF was 14 ml/min and the mass removal was 6.7 mg/3 h. Ara-C and Ara-U are eliminated by HD and HF in anuric patients. A continuous infusion of 100 mg Ara-C m2/d during HD or HF treatment did not result in a serum concentration above 200 ng/ml.

Efficacy and safety of growth hormone treatment in short children with renal allografts: three year experience. Members of the German Study Group for Growth Hormone Treatment in Children with Renal Allografts

The majority of children with renal allografts have diminished growth and reduced final height. Impaired allograft function and glucocorticoid treatment are the main contributing factors. Since recombinant human growth hormone (rhGH) treatment was able to counteract the growth depressing effects of glucocorticoids in experimental uremia, an open-labeled prospective study in 17 short children with renal allografts was designed to investigate the efficacy of rhGH therapy (30 IU/m2/week) with special emphasis on the safety regarding graft function and carbohydrate metabolism. Height velocity in prepubertal children (N = 10) increased from baseline median 2.2 cm/year to 7.9 cm/year after one year (P < 0.01), 7.2 cm/year after two years (P < 0.01), and 5.5 cm/year (P < 0.05) after three years of rhGH therapy. This resulted in a normalization of height in three out of seven patients after two years and in three out of five after three years of therapy. Growth stimulation in pubertal children was less consistent. Bone maturation paralleled chronological age. The effect of rhGH treatment on longitudinal growth may be partially attributable to the improved ratio between the serum concentration of the insulin-like growth factor (IGF)-I and its major binding protein (BP) IGFBP-3 leading to a normal IGF bioactivity. The incidence of acute rejection crises in the study group (corrected for time after grafting) did not differ from that of untreated retrospective "controls" (0.10 vs. 0.12 episodes per patient and year). No systematic effect of rhGH on glomerular filtration rate assessed by repeated inulin and creatinine clearances was noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Kinetics of serum 1,84 iPTH after high dose of calcitriol in uremic patients

The temporal relation between oral administration of calcitriol and the nadir of PTH concentration is important for selecting optimal schedules of administration of calcitriol in the treatment of secondary hyperparathyroidism. To further assess this issue we examined 9 patients with preterminal renal failure (3 females, 6 males; median age 58.0 years, range 47-64, median S-Crea 4.8 mg/dl, range 3.7-6.8) with elevated baseline concentrations of 1,84 iPTH (median 46.0 pmol/l, range 18-100). After ingestion of a single oral dose of 2.0 micrograms calcitriol a transient rise in 1,25(OH)2D3 levels was seen with a peak at 6 h (from 20 pg/ml; 14-52 to 43 pg/ml; 35-102). 1,84 iPTH levels did not significantly change in the first 24 h, but were decreased significantly (p 0.01) 48 h after a single oral dose of calcitriol, the time to reach nadir varying from 24 to 96 hours. The percent decrease wa highest in patients with the highest baseline concentrations of 1,84 iPTH. Median 1,84 iPTH levels continued to remain below baseline at 48 h (25.0 pmol/l), 72 h (24.0 pmol/l) and 96 h (24.0 pmol/l) after oral calcitriol. A modest increase of S-Ca was noted which was not statistically significant. We conclude that 1. a single dose of oral calcitriol causes a delayed but long-lasting decrease of 1,84 iPTH, 2. decreased 1,84 iPTH levels persist despite return of calcitriol concentrations to baseline levels and 3. 1,84 iPTH may remain below baseline for more than 96 h.

Changing pattern of chronic renal failure and renal replacement therapy in children and adolescents: a 20-year single centre study

We analysed the demographic data, clinical course and survival on different forms of renal replacement therapy (RRT) of 374 children and adolescents with chronic renal failure observed between 1969 and 1988 and compared the findings for the four subsequent 5-year periods. The proportion of children below 5 years of age rose from 21% to 47%. With time the incidence of glomerulonephritis increased and that of pyelonephritis decreased. As RRT became more common, more very young children and more adolescents were admitted to the study. In the last 5 years continuous ambulatory peritoneal dialysis (CAPD) and haemodialysis (HD) were performed to the same extent as the initial form of RRT. The time a subject had to wait for a first transplant decreased from 36 to 21 months. Between 1969 and 1988 overall survival on any form of RRT increased to 77% after 10 years of therapy. In the last observation period 2-year patient survival was 100% both on HD and CAPD. First cadaver graft survival after 4 years improved from 25% in 1969-1973 to 69% in 1984-1988.

Growth hormone-induced glomerular hyperfiltration is dependent on vasodilating prostanoids

Exogenous growth hormone (GH) and insulin-like growth factor (IGF)-I induce an increase of renal hemodynamics in normal subjects, but the precise mechanism mediating this phenomenon has not been explored in humans. We investigated whether the renal response to exogenous GH requires the presence of vasodilating prostaglandins (PG). In 10 healthy normotensive women with normal renal function, the effect of recombinant human (rh)GH on glomerular filtration rate (GFR) was examined using an intraindividual cross-over design. The subjects were studied under conditions of normal hydration and controlled sodium and protein intake without and with coadministration of indomethacin, 150 mg/d. rhGH, 4.5 IU twice per day, was administered by subcutaneous self-injection for 3 days. GFR was measured as inulin clearance (Cin) in the morning hours in the fasting state in supine position before and after 3 days of rhGH treatment. Baseline GFR was 115.7 +/- 10.1 (SD) mL/min/1.73 m2. Three days of treatment with rhGH caused a 50% increase in serum IGF-I values and GFR increased by 10% to 127.9 +/- 11.7 mL/min/1.73 m2 (P < 0.03). The study was repeated under coadministration of indomethacin, which was started 2 days before application of rhGH. Despite a similar increase in serum IGF-I values, the increase in GFR was completely blocked by indomethacin. Urinary PGE2 excretion was not stimulated by rhGH, but decreased by 50% during indomethacin treatment, as expected. These findings suggest that the increase of GFR during GH treatment in humans is mediated by or requires the presence of vasodilating prostanoids.

Growth hormone treatment in children with preterminal chronic renal failure: no adverse effect on glomerular filtration rate

Impaired growth and stunting remains a major therapeutic problem in children with chronic renal failure (CRF). Recombinant human growth hormone (rhGH) treatment may be beneficial, but concern has been raised about possible side-effects, i.e. deterioration of renal function and glucose intolerance. We have treated 10 prepubertal children with CRF (median age 7.5 [1.7-10.0] years) with 4 IU rhGH/m2 per day s.c. over a period of 1 year. Height velocity increased significantly (P less than 0.03) from basal 4.6 (2.0-14.0) cm/year to 9.7 (6.8-17.6) cm/year. Height velocity SDS for chronological age and for bone age increased in all children from basal median -2.3 to +3.8 (P less than 0.005). Median glomerular filtration rate (GFR) measured by single injection inulin clearance at onset was 18 (11-66) ml/min per 1.73 m2 and did not change significantly during the treatment year. The loss of GFR as estimated by creatinine clearance was similar during the treatment year (median loss 1.3 ml/min per 1.73 m2) compared to the year before treatment (median loss 3.7 ml/min per 1.73 m2). Serum glucose levels during an oral glucose tolerance test did not change, but fasting as well as stimulated insulin levels increased significantly with time during the study period. It is concluded that the rhGH regimen employed was remarkably effective in improving growth velocity in children with CRF without adversely affecting GFR. Glucose homeostasis remained stable, but at the expense of increased serum insulin levels.

Growth failure in renal disease

Children with congenital CRF lose height potential mainly during two distinct growth periods; infancy and puberty. The onset of puberty is late, the pubertal growth spurt starts from a very low rate of growth velocity, and peak height velocity is lower than normal although the absolute increment of height velocity is comparable to the increment in normal children. Furthermore, the duration of pubertal growth spurt is reduced in CRF. During infancy and early childhood, malnutrition, electrolyte disturbances and metabolic acidosis are the main contributing factors for reduced growth, whereas hormonal disturbances are responsible for growth impairment during puberty. There is evidence for resistance to growth hormone in CRF, which starts in early childhood and persists until the end of puberty. Growth hormone secretion is normal in CRF, but GH half-life is prolonged. The binding activity of the stable growth hormone binding protein is reduced, which points to a low receptor expression in the liver. Hepatic IGF-I production is diminished. However, the serum concentration of IGF binding proteins (IGFBP) is increased due to reduced renal filtration of low molecular weight subunits of IGFBP. Mainly, the accumulation of IGFBP-3 leads to increased IGF-binding capacity of the uraemic serum. Both, reduced IGF-I production and increased binding of IGF to IGFBP-3 result in decreased IGF bioactivity. During infancy, loss of growth potential can be prevented by adequate nutrition. Later in life, catch-up growth cannot be induced by nutritional intervention or dialysis. Renal transplantation allows catch-up growth in only a small percentage of patients. Treatment with one IU rhGH/kg/week improves growth velocity and growth in all stages of renal disease. The mean increment of height in prepubertal children is +1.5 SDS within two treatment years. The effect of rhGH during puberty as well as the effect on final height remain to be determined.

Growth hormone in renal transplantation--the mode of action, animal studies, and clinical use

During circulation, growth hormone (GH) is bound to about 50% by the high-affinity, low-capacity GH-binding protein (BP). GHBP represents the extracellular binding domain of the GH receptor and modulates the action of GH. After binding to its receptor, GH induces the local production of insulin-like growth factor 1 (IGF-1) by autocrine and paracrine mechanisms. In uremia, the plasma GH-binding activity is low and does not get up-regulated by recombinant human GH treatment, which is in contrast to the experience in short, normal children. There is evidence that hepatic IGF-1 production is low, whereas the serum concentration of IGF-binding protein 3 (IGF-BP3) and other IGFBPs is increased because of the reduced renal clearance of the low-molecular-weight fragment of IGF-BP. This result in the reduced bioavailability of free IGF-1 and reduced IGF bioactivity. There is a strong interaction between GH and corticosteroids. Corticosteroids suppress growth by reducing the food efficiency ratio (weight gain per food intake), reduce pituitary GH secretion, and decrease the local production of and cell responsiveness for IGF-1. The growth-depressing and catabolic effects of corticosteroids can be counterbalanced dose dependently by recombinant human GH in animal experiments, and growth can be improved in corticosteroid-treated renal allograft recipients with and without normal renal function. It is not clear at this time to what extent GH may induce acute or chronic rejection crises.

Lipid levels in monocytes of patients with moderate hyperlipoproteinemia

Recent studies suggest that circulating blood monocytes may serve as a lipid clearance system in early atherosclerotic lesions. To evaluate the influence of moderate hyperlipoproteinemia on monocyte lipid concentrations, we measured fasting serum and monocyte lipid levels in 7 healthy individuals, in 7 patients with primary hypercholesterolemia and in 17 patients with secondary dyslipidemia due to chronic renal failure; 10 of these patients were treated by hemodialysis (HD) and 7 patients by continuous ambulatory peritoneal dialysis (CAPD). The hypercholesterolemic patients had elevated serum levels of total cholesterol, LDL-cholesterol and apolipoprotein (apo) B, but normal plasma triglycerides. Patients on dialysis had elevated serum levels of triglycerides, serum cholesterol (CAPD only) and VLDL- and LDL-cholesterol (CAPD only) and apo B (CAPD only), whereas HDL-cholesterol and apo A-I levels (HD only) were decreased. In monocytes, we measured the content of free cholesterol (FC), cholesteryl esters (CE) and triglycerides (TG). The normal mean intracellular concentrations of FC, CE and TG were 48.3, 1.7 and 2.4 micrograms/mg cell protein, respectively. All monocyte lipid levels were similar in patients and controls, with the exception of a decreased content of FC (30.8 micrograms/mg) in monocytes of HD patients. We conclude that moderate increases in serum lipoprotein lipid levels are not associated with lipid accumulation in monocytes.

Evaluation of peritoneal solute transfer by the peritoneal equilibration test in children

To evaluate the characteristics of peritoneal kinetics in the young, we investigated solute and water transfer rates by a modified Peritoneal Equilibration Test (PET) in 20 pediatric patients aged 1.9 to 19.8 years. 1000 ml/m2 body surface area of a 2.3% glucose PD solution were instilled in the peritoneal cavity. Glucose, creatinine, urea, sodium, potassium and phosphate were measured in the dialysate (D), 7 times during 4 hours and in plasma (P) after 2 hours dwell time. At 4 hours, the mean (+/- SD) D/P ratio was 1.06 +/- 0.16 for urea, 0.79 +/- 0.14 for creatinine, 0.82 +/- 0.21 for potassium, 0.92 +/- 0.04 for sodium and 0.79 +/- 0.30 for phosphate. Mean D/D0 of glucose was 0.36 +/- 0.13. The 4-hour solute equilibration curves were analytically best approximated by logarithmic functions for urea (mean R2 = 0.983), creatinine (R2 = 0.973) and potassium (R2 = 0.979), by a linear function for phosphate (R2 = 0.964), and by an exponential model for glucose (R2 = 0.969). The linear or exponential regression coefficients were used to express the peritoneal solute transfer rates. Although the transfer rates of most solutes were correlated with each other, the individual variation of peritoneal permeability for different solutes was high. Close associations were observed between the glucose and creatinine transfer rates (r = 0.91, p < 0.0001) and between ultrafiltration rate and glucose (r = -0.90, p < 0.0005) and creatinine (r = -0.88, p < 0.005). Peritoneal permeability for all solutes tended to be inversely correlated with body size (urea transfer rate vs. height: r = 0.49, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of relapsing peritonitis in pediatric patients on peritoneal dialysis

Relapsing peritonitis is often due to bacterial colonization of the Tenckhoff catheter and may require removal of the catheter in patients on peritoneal dialysis. The efficacy of a Tenckhoff catheter decontamination procedure was examined in 9 pediatric patients aged 1.5-18 years and compared to the outcome of a historical control group. After repeated dialysate cultures had become negative and cell count was normalized (< 100/ul), intraluminal urokinase (5000 IU/ml) and intraluminal high concentrated antibiotics (vancomycin, fosfomycin, cefotaxim) were instilled sequentially for 3 h and 1 h respectively. This procedure was performed once daily for three days. In addition, the connector was exchanged on the last day. This regimen prevented relapsing peritonitis in all study patients, whereas in the control group in 75.8% of events further relapses occurred, necessitating removal of the Tenckhoff catheter in 7/19 (36.8%) episodes. No side effects of intraluminal urokinase were recorded in any of the patients. We conclude that intraluminal urokinase and intraluminal high concentrated antibiotics combined with connector device exchange are highly effective for prevention of further relapses of peritonitis and reduce the need for Tenckhoff catheter exchange.

Growth hormone prevents steroid-induced growth depression in health and uremia

Treatment with supraphysiological doses of corticosteroids results in protein wasting and impairment of growth, whereas exogenous growth hormone (GH) causes anabolism and improvement of growth. We wanted to know whether the growth depressing effects of methylprednisolone (MP) are more expressed in an organism which is chronically diseased and whether these effects can be counterbalanced by concomitant treatment with recombinant human growth hormone (rhGH). MP in doses from 1 to 9 mg/kg/day caused a dose dependent reduction of length gain, weight gain and weight gain/food intake ratio in 140 g healthy female Sprague-Dawley rats. Food intake was not affected by MP. This points to a change in food metabolism as a mechanism for growth impairment. In addition, treatment with MP inhibited endogenous GH secretion, documented by serum GH concentration profiles over seven hours, decreased IGF-1 serum concentration and disturbed growth cartilage plate architecture. Concomitant treatment with 2.5 to 20 IU/rhGH/kg/day prevented the negative effects of MP on growth in a dose dependent manner and normalized growth plate architecture. In uremic rats in which food efficiency and growth was already reduced, 6 mg MP/kg/day further decreased length gain and prevented weight gain completely by bringing the weight gain/food conversion ratio to the nadir. All effects of MP including reduction of muscle mass could be prevented by concomitant treatment with 10 IU rhGH/kg/day. The effects of MP and rhGH on food efficiency and growth in uremic animals were numerically nearly identical to those in pair fed ad libitum fed controls, but this may be more relevant in the diseased organism in which basal growth is already suppressed.

Effects of two years of growth hormone treatment in short children with renal disease. The German Study Group for Growth Hormone Treatment in Chronic Renal Failure

The effect of 1-2 years of growth hormone (GH) treatment (28-30 IU/m2/week) on growth rate, bone age, renal function and metabolic parameters was studied in 61 short, slowly growing children with chronic renal disease (20 with preterminal chronic renal failure (CRF), 24 with end-stage renal failure (ESRF) and 17 with functioning renal transplants). Height velocity (2-year data) significantly increased in children with preterminal CRF from a baseline median of 4.1 cm/year to 9.2 cm/year after 1 year and to 6.6 cm/year after 2 years of treatment. In patients with transplants, the corresponding values were 2.6 cm/year before GH treatment and 8.6 and 7.2 cm/year after 1 and 2 years, respectively. This resulted in normalization of height in 8 of the 16 children who completed 2 years of treatment. The growth response after 1 year in children with preterminal CRF was significantly higher than that in children with ESRF. Bone maturation was in proportion to the increase in chronological age; the expected final height of the children therefore increased by approximately 8-10 cm. In children with preterminal CRF, the decrease in glomerular filtration rate was not affected by 2 years of treatment with GH. The incidence of acute rejection in children with transplants was low; however, a slight stimulatory effect of GH could not be excluded. The major metabolic change induced by exogenous GH was an increase in serum levels of insulin in the three treatment groups, though all glucose tolerance tests remained stable over the 2-year period.