Presentation of pediatric Henoch-Schönlein purpura nephritis changes with age and renal histology depends on biopsy timing.

BACKGROUND: This study correlates the clinical presentation of Henoch-Schönlein purpura nephritis (HSPN) with findings on initial renal biopsy. METHODS: Data from 202 pediatric patients enrolled in the HSPN registry of the German Society of Pediatric Nephrology reported by 26 centers between 2008 and 2014 were analyzed. All biopsy reports were re-evaluated for the presence of cellular crescents or chronic pathological lesions (fibrous crescents, glomerular sclerosis, tubular atrophy >5%, and interstitial fibrosis >5%). RESULTS: Patients with HSPN with cellular glomerular crescents were biopsied earlier after onset of nephritis (median 24 vs 36 days, p = 0.04) than those without, whereas patients with chronic lesions were biopsied later (57 vs 19 days, p < 0.001) and were older (10.3 vs 8.6 years, p = 0.01) than those without. Patients biopsied more than 30 days after the onset of HSPN had significantly more chronic lesions (52 vs 22%, p < 0.001), lower eGFR (88 vs 102 ml/min/1.73m2, p = 0.01), but lower proteinuria (2.3 vs 4.5 g/g, p < 0.0001) than patients biopsied earlier. Children above 10 years of age had lower proteinuria (1.98 vs 4.58 g/g, p < 0.001), lower eGFR (86 vs 101 ml/min/1.73m2, p = 0.002) and were biopsied significantly later after onset of nephritis (44 vs 22 days, p < 0.001) showing more chronic lesions (45 vs 30%, p = 0.03). Proteinuria and renal function at presentation decreased with age. CONCLUSIONS: In summary, we find an age-dependent presentation of HSPN with a more insidious onset of non-nephrotic proteinuria, impaired renal function, longer delay to biopsy, and more chronic histopathological lesions in children above the age of 10 years. Thus, HSPN presents more like Immunoglobulin A (IgA) nephritis in older than in younger children.

Predicting the response to growth hormone treatment in short children with chronic kidney disease.

CONTEXT: Short stature in children with chronic kidney disease (CKD) is due to various underlying congenital or acquired renal disorders resulting in variable impairment of renal function and variable response to GH treatment. OBJECTIVE: It was the aim to develop a mathematical model that allows the prediction of the individual growth response and to identify nonresponders. DESIGN: Data from 208 prepubertal children on conservative or dialysis treatment in a large pharmaco-epidemiological survey, the KIGS (Pfizer International Growth Database), were used for the model and data from 67 similar CKD patients registered at the Dutch Growth Research Foundation for validation. RESULTS: Annualized height velocity (centimeters per year) during the first year of GH treatment was best predicted by age at start, weight sd score, underlying renal disorder (hereditary kidney disorder), glomerular filtration rate (at baseline), and GH dosage. Using these parameters, the final model explained 37% of the overall variability of growth response. Standard error of the estimates was 1.6 cm. Age was the most important predictor of growth response (20.3% of variability) followed by weight sd score at start, and 27.2% of the variability of the second-year response could be predicted by the first-year response and glomerular filtration rate. Nonresponders of the validation group could be correctly identified. CONCLUSION: Based on simple clinical variables, a robust prediction model was developed that provides realistic expectations of individual growth response to GH in short children with CKD. The model will help in identifying nonresponders and to tailor treatment strategies.

Short-term growth hormone treatment and microcirculation: effects in patients with chronic kidney disease.

Endothelial dysfunction is common in patients with chronic kidney disease (CKD) and contributes significantly to the high long-term cardiovascular morbidity and mortality. The short-term cardiovascular effects of recombinant human growth hormone (rhGH) in CKD patients (stages III-V) and healthy controls (n=15 each) were explored in a single-center, non-randomized pilot study. Subjects were investigated before, after a 7 day treatment with rhGH, and after a 7 day wash-out period. Microcirculation was assessed by nailfold capillaroscopy and leg strain gauge plethysmography. Echocardiography was performed and serum concentrations of IGF-I and IGF-binding protein-3 (IGFBP-3) were determined. Before the start of rhGH therapy, mean post-ischemic maximum flow velocity of erythrocytes (V(RBC)) and leg blood flow (LBF) in CKD patients were significantly reduced to 68% and 75% of that seen in controls, whereas V(RBC) and LBF under resting conditions were comparable. Treatment with rhGH significantly increased V(RBC) and LBF under resting conditions. Whereas maximum post-ischemic V(RBC) was improved by rhGH in patients and controls, maximum post-ischemic LBF increased in controls only. This was paralleled by a non-significant reduction of total vascular resistance, and increased heart rate and cardiac index. In conclusion, CKD patients respond to short-term rhGH treatment with significantly improved capillary blood flow, whereas only minor effects on total peripheral resistance and cardiac output were noted.

Factors predicting the near-final height in growth hormone-treated children and adolescents with chronic kidney disease.

CONTEXT: GH therapy is an accepted measure to increase adult height in young prepubertal patients suffering from growth failure related to chronic kidney disease (CKD). The impact of GH therapy on final height (FH) in CKD patients of pubertal age is unclear. OBJECTIVE: This study set out to analyze near-FH in a cohort of GH-treated CKD patients. DESIGN, SETTINGS, AND PATIENTS: Of 240 evaluable patients in the Pfizer International Growth Database (KIGS) with CKD, 39% were prepubertal and 61% were pubertal at baseline; 45% were on conservative treatment for CKD, 28% were on dialysis, and 27% were in the period after renal transplantation. MAIN OUTCOME MEASURES: Near-FH, relation to pubertal stage, and factors predictive of growth response were the main outcome measures. RESULTS: Mean height sd scores increased continuously during GH treatment until near-FH by 1.2 and 1.6 in boys and girls, respectively. Mean near-FH differed significantly from prepubertal patients showing severely delayed puberty (-3.6), late pubertal patients (-2.9), early pubertal patients (-2.2), and prepubertal patients with normal onset of puberty (-2.0). The initial degree of stunting, degree of bone age retardation, duration of GH therapy, time spent on conservative treatment/dialysis, pubertal delay (>2 sd), gender, and age at start of GH treatment were significant predictors of growth response to GH therapy, explaining between 33 and 61% of the overall variability. CONCLUSIONS: Long-term GH therapy of CKD patients in prepubertal and pubertal age results in an increased adult height, but response is diminished in patients on dialysis and/or with severely delayed puberty.

Growth impairment shows an age-dependent pattern in boys with chronic kidney disease.

The impact of chronological age on longitudinal body growth from early childhood through adolescence using detailed anthropometric methods has not yet been studied in children with chronic kidney disease (CKD). We have evaluated growth failure by measuring four components of linear growth: body height (HT), sitting height (SHT), arm length (AL) and leg length (LL). Data were prospectively collected for up to 7 years on 190 boys (3-21 years old) with congenital or hereditary CKD (all had developed at least stage 2 CKD by the age of 10 years). Patients showed the most severe growth failure in early childhood, followed by an acceleration in growth in pre-puberty, a slowing-down of growth at puberty, as expected, and thereafter a late speeding-up of growth until early adulthood. This pattern was observed irrespective of the degree of CKD and different treatment modalities, such as conservative treatment, recombinant human growth hormone (rhGH) therapy or transplantation. LL showed the most dynamic growth changes of all the parameters evaluated and emerged as the best indicator of statural growth in children with CKD. A specific age-dependent pattern of physical growth was identified in pediatric male CKD patients. This growth pattern should be considered in the evaluation of individual growth and the assessment of treatment efficacy such as rhGH therapy.

Body growth after combined liver-kidney transplantation in children with primary hyperoxaluria type 1.

BACKGROUND: Children with primary hyperoxaluria type 1 (PH1) often develop severe growth failure, which is related to metabolic and endocrine consequences of chronic renal failure, and/or oxalate deposition in bone and cartilage. Combined liver and kidney transplantation (LKT) corrects the underlying metabolic defect and restores renal function in these children. METHODS: We therefore analyzed longitudinal growth of 24 children with PH1 who underwent LKT at nine European centers. Mean age at LKT was 8.9 years, and mean duration of follow-up was 5.7 years. RESULTS: After LKT mean standardized height tended to increase from -1.79 SD to -1.47 SD until last observation. Mean adult height amounted to 167 cm and 158 cm in boys and girls, respectively. At last observation, seven out of 24 patients were stunted. Within the whole study population, the degree of catch-up growth after LKT was positively associated with degree of stunting at the time of LKT and negatively associated with prednisolone dosage explaining together 39% of the overall variability. CONCLUSIONS: Combined LKT does not induce true catch-up growth in the majority of children with PH1. Due to the preexisting growth retardation at the time of LKT, one third of patients end up with a reduced final height.

Arterial and cardiac disease in young adults with childhood-onset end-stage renal disease-impact of calcium and vitamin D therapy.

BACKGROUND: Studies in patients with childhood-onset end-stage renal disease (ESRD) provide a diagnostic window to the evolution of cardiovascular disease (CVD) in this population. Hyperphosphataemia and renal osteodystrophy are particularly difficult to treat in paediatric patients, but there is only limited information regarding the effect of calcium-containing phosphate binders and vitamin D preparations on the development of CVD in the young. METHODS: We studied 40 adult patients (mean age 23.6 years) who developed ESRD at the age of 11.5 +/- 4 years and 40 matched healthy control subjects. Nine patients were on dialysis and 31 had a functioning kidney transplant. Measurements included intima-media thickness (IMT) of the common carotid artery, electron beam computed tomography (EBCT) for the detection of coronary artery calcifications (CAC), echocardiography and post-ischaemic arterial blood flow by venous occlusion plethysmography. Patient characteristics, atherosclerotic risk factors and a complete account of prescribed medications were analysed for correlations with arterial and cardiac changes. RESULTS: The IMT was not significantly different in patients and controls; four patients (10%) had coronary calcifications on EBCT. Twenty-five patients (62.5%) had left ventricular hypertrophy. Patients had a 40% reduction of post-ischaemic arterial flow. Morphological alterations of the heart and arteries were significantly correlated with the duration of ESRD and dialysis time, and with the cumulative intake of calcium-containing phosphate binders and active vitamin D preparations. Functional changes (vascular reactivity) were correlated with duration of ESRD and non-traditional risk factors. CONCLUSIONS: Young adults with ESRD since childhood have systemic CVD characterized by a decrease in arterial elasticity, the occurrence of CAC and changes in left ventricular morphology. Treatment with calcium-containing phosphate binders and active vitamin D preparations is independently associated in a dose-dependent manner with surrogate markers for CVD.

Systemic cardiovascular disease in uremic rats induced by 1,25(OH)2D3.

OBJECTIVE: Vitamin D may contribute to cardiovascular disease in the absence of hypercalcemia in patients with chronic kidney disease. METHODS: We investigated the effects of long-term (6-week) treatment with 1,25(OH)2D3, at a non-hypercalcemic dosage (0.25 microg/kg per day per orally) in 5/6 nephrectomized rats: (i) vehicle-treated, sham-operated rats; (ii) 1,25(OH)2D3-treated, sham-operated rats; (iii) vehicle-treated, 5/6 nephrectomized rats; and (iv) 1,25(OH)2D3-treated, 5/6 nephrectomized rats. RESULTS: Creatinine clearance after 6 weeks was significantly lower and parathyroid hormone levels were significantly higher in 1,25(OH)2D3-treated uremic rats, compared with uremic controls (P < 0.01). Serum calcium levels, as well as the calcium-phosphorus product, did not differ between both groups. Mean systolic blood pressure in 1,25(OH)2D3-treated animals was significantly increased, compared with vehicle (each P < 0.01). In addition, 1,25(OH)2D3-treated uremic animals showed left ventricular hypertrophy. Diffuse aortic calcification involving the intima and media layer occurred in 1,25(OH)2D3-treated uremic animals, but not in other groups. The mean aortic wall area and lumen area were increased two-fold in 1,25(OH)2D3-treated uremic animals compared with vehicle (P < 0.01), whereas the wall/lumen ratio remained unchanged, indicating fusiform aneurysm formation. CONCLUSIONS: Hypertension, left ventricular hypertrophy, aortic calcification, and aneurysm, without hypercalcemia, occurred in 1,25(OH)2D3-treated, 5/6 nephrectomized rats. These data indicate a permissive effect of uremia for cardiovascular damage induced by non-hypercalcemic doses of 1,25(OH)2D3.

Effect of renal transplantation in childhood on longitudinal growth and adult height.

BACKGROUND: Severe growth failure is frequently observed in children suffering from end-stage renal disease (ESRD). METHODS: We analyzed the effect of renal transplantation (RTx) on longitudinal growth and final height in 37 children (19 girls) with ESRD with a mean follow-up of 8.5 years. The mean age at RTx was 11.3 years. RESULTS: In children transplanted before start of puberty, mean height velocity increased significantly from 4.9 to 8.0 cm/year (P < 0.01), resulting in an increase in standardized height of 0.6 SD within two years post RTx. Although peak height velocity during puberty was significantly increased compared with healthy children, total pubertal height gain was reduced by 20% because of its shortened duration. Mean standardized height significantly increased from the time of RTx until final height by 1.3 SD and 0.7 SD in children transplanted before and after start of puberty, respectively. Mean adult height (boys 170 cm; girls 151 cm) was normal (> -2 SD) in 68% of patients. Change in standardized height from RTx until adult height was associated with initial degree of stunting and glomerular filtration rate (GFR; cumulative r2 0.49). Total pubertal height gain was associated with the age at start of puberty, GFR, and age at RTx (cumulative r2 0.57). CONCLUSION: RTx in children with ESRD induces moderate catch-up growth during the prepubertal growth period. However, final height is reduced in about one third of patients due to the reduced pubertal height gain and preexisting height deficit at the time of RTx.

Effects of growth hormone treatment on body proportions and final height among small children with X-linked hypophosphatemic rickets.

BACKGROUND: X-linked hypophosphatemic rickets (XLH) is characterized by rickets, disproportionate short stature, and impaired renal phosphate reabsorption and vitamin D metabolism. Despite oral phosphate and vitamin D treatment, most children with XLH demonstrate reduced adult height. OBJECTIVE: To determine the beneficial effects of recombinant human growth hormone (rhGH) therapy on body proportions and adult height among patients with XLH. METHODS: Three initially prepubertal short children (age, 9.4-12.9 years) with XLH were treated with rhGH for 3.1 to 6.3 years until adult height was attained. RESULTS: rhGH treatment led to sustained increases in standardized height for all children. The median adult height was 0.9 SD (range: 0.5-1.3 SD) greater than that at the initiation of rhGH treatment and exceeded the predicted adult height by 6.2 cm (range: 5.3-9.8 cm). However, longitudinal growth of the trunk was stimulated more than leg growth. During rhGH treatment, the standardized sitting height increased by 1.6 SD (range: 1.1-2.7 SD), compared with baseline values. In contrast, the median subischial leg length did not change consistently (median change: 0.3 SD; range: -0.1 to 0.6 SD). CONCLUSION: The increase in final height after rhGH treatment is of potential benefit for children with XLH. However, the exaggeration of disproportionate truncal growth observed for our prepubertal patients is a potential negative effect of treatment and should be confirmed with additional studies.