In agreement with recent studies showing a deleterious effect of growth hormone treatment in critically ill patients, preliminary data showed that insulin-like growth factor I (IGF-I) administration increased the mortality rate of rats with ischemic acute renal failure (ARF). The present study was designed to investigate the mechanism responsible for this unexpected effect. Male rats with ischemic ARF were given subcutaneous IGF-I, 50 microg/100 g at 0, 8, and 16 h after reperfusion (ARF+IGF-I, n = 5) or were untreated (ARF, n = 5). A group of 5 sham-operated rats were used as controls. Rats were killed 48 h after declamping, and the following studies were performed: in serum, creatinine and urea nitrogen; and in kidneys, histologic damage score, cellular proliferation by bromodeoxyuridine labeling, apoptosis by morphologic criteria, macrophage infiltration by immunohistochemistry using a specific antibody against ED-1, neutrophil infiltration by naphthol AS-D chloroacetate esterase staining, and levels of IGF-I and IGF-I receptor mRNA by RNase protection assay. ARF and ARF+IGF-I groups had a severe and similar degree of renal failure. Kidney damage was histologically more evident in ARF+IGF-I (1.9 +/- 0.1) than in ARF (1.3 +/- 0.2) rats, and the number of neutrophils/mm(2) of tissue was significantly greater in ARF+IGF-I than in ARF rats at the corticomedullary junction (52.3 +/- 5.2 versus 37.2 +/- 4.1) as well as at the renal medulla (172.5 +/- 30.0 versus 42.1 +/- 9.6). No other differences between the groups were found. It is concluded that IGF-I treatment enhanced the inflammatory response in rats with ischemic ARF. Cell toxicity derived from increased neutrophil accumulation might play a key role in the greater mortality risk of critically ill patients that are treated with growth hormone.

Bilateral clamping of renal pedicles during 60, 75 or 90 min was used to characterize the evolution of ischemic acute renal failure (ARF) in prepubertal rats. To verify the existence of age-conditioned differences in the evolution of ARF, adult rats were exposed to 40, 60 or 75 min of clamping. After 7 days, survival rate was significantly better in young than adult rats for identical times of clamping (89 vs. 35% for 60 min and 69 vs. 35% for 75 min). Young rats largely died within the first 24 h following ischemia while the risk of death extended until the 4th day after ischemia in adult rats. Peak values of serum urea nitrogen and creatinine were observed on the 1st and 3rd day after ischemia in young and adult rats, respectively. In young rats, these markers of renal function returned to normal on days 5 and 6 whereas they remained elevated at the end of the study in adult animals. Growth curves of young rats paralleled those of sham-operated animals from the 3rd day of clamping whereas adult rats did not even reach the initial weight at the end of the study. Analysis of kidneys obtained 7 days after clamping revealed more severe histopathological lesions in adult rats as well as a higher proliferative activity (10–40 times the value of sham-operated animals versus 2–4 times the control value in young rats). Our findings indicate that kidneys from young rats are more resistant to ischemia and recover more quickly from the ischemic insult. Therefore, the experimental model of ischemic ARF is clearly different in young and adult rats.

To characterize the modifications of growth plate in individuals with growth impairment secondary to chronic renal failure, young rats were made uremic by subtotal nephrectomy (NX) and, after 14 d, their tibial growth plates were studied and compared with those of sham-operated rats fed ad libitum (SAL) or pair-fed with NX (SPF). NX rats were growth retarded and severely uremic. Growth plate height (mean +/- SD) was much greater (P<0.05) in NX (868.4+/-85.4 microm) than SAL (570.1+/-93.5 microm) and SPF (551.9+/-99.7 microm) rats as a result of a higher (P<0.05) hypertrophic zone (661.0+/-89.7 versus 362.8+/-71.6 and 353.0+/-93.9 microm, respectively). The increased size of the growth plate was associated with a greater number of chondrocytes and modifications in their structure, particularly in the hypertrophic zone adjacent to bone. In this zone, chondrocytes of NX animals were significantly (P<0.05) smaller (12080.4+/-1158.3 microm3) and shorter (34.1+/-2.5 microm) than those of SAL (16302.8+/-1483.4 microm3 and 37.8+/-2.0 microm) and SPF (14465.8+/-1521.0 microm3 and 36.3+/-1.8 microm). The interface between the growth plate cartilage and the metaphyseal bone appeared markedly irregular in NX rats. Kinetics of chondrocytes was also modified (P<0.05) in the NX rats, which had lower cell turnover per column per day (5.4+/-0.9), longer duration of hypertrophic phase (89.0+/-15.2 h), and reduced cellular advance velocity (7.4+/-2.2 microm/h) compared with SAL (8.0+/-1.6, 32.1+/-6.7 h, and 11.3+/-2.7 microm/h) and SPF (7.2+/-1.1, 34.8+/-5.1 h, and 10.1+/-2.5 microm/h). Cell proliferation was no different among the three groups. Because the growth plates of SPF and SAL rats were substantially not different, modifications observed in the NX rats cannot be attributed to the nutritional deficit associated with renal failure. These findings indicate that chronic renal failure depresses both the activity of the growth plate cartilage by altering chondrocyte hypertrophy and the replacement of cartilage by bone at the metaphyseal end. The two processes are differentially depressed since cartilage resorption is more severely lowered than cartilage enlargement and this leads to an accumulation of cartilage at the hypertrophic zone.

1. Growth hormone (GH) increases glomerular filtration rate and renal plasma flow and decreases renal vascular resistance. Sustained GH-induced hyperfiltration might be undesirable in children with chronic renal failure (CRF) who are receiving recombinant human GH (rhGH) therapy. 2. In order to determine the effect of CRF on vascular reactivity and the modifications induced by rhGH administration, two endothelium-dependent effects, acetylcholine relaxation and decrease of contractile response to noradrenaline, were studied in aorta segments of various groups of male Sprague-Dawley rats: CRF rats (CRF, n = 8) with serum urea nitrogen (SUN) 68 +/- 16 mg dl-1 (mean +/- SEM), CRF rats treated with intraperitoneal rhGH at 10 IU kg-1 day-1 for 13 days (CRFGH, n = 6, SUN = 88 +/- 15 mg dl-1), sham operated rats (SHAM, n = 8, SUN: 21 +/- 1 mg dl-1) and control rats (CONTROL, n = 8, SUN 20 +/- 1 mg dl-1), housed in identical conditions but without undergoing surgical intervention or manipulation. CRF was induced by 5/6 two stage nephrectomy. 3. Rats were sacrificed and a segment of thoracic aorta was immediately removed, cut into spirals, and suspended in organ baths according to standard procedures. First, dose-response curves to noradrenaline and acetylcholine relaxation, in strips previously exposed to noradrenaline, were determined. Then, the endothelium was removed and both dose-response curves were repeated. Acetylcholine induced a greater relaxation, P < 0.05, in the aorta of CONTROL rats (82.6 +/- 6.1%) as compared with SHAM (60.3 +/- 4.7%), CRF (60.0 +/- 6.8%) and CRFGH (54.8 +/- 8.2%) rats. 4. Endothelium removal only caused a greater contractile response to noradrenaline (10(-9) and 3 x 10(-9)M) in the CONTROL group, P < 0.05. 5. No differences to acetylcholine and noradrenaline responses were found among the SHAM, CRF and CRFGH groups. 6. These results suggest that the endothelium-dependent vascular reactivity was modified by the experimental protocol to induce chronic renal failure but no further changes resulted from uraemia and rhGH treatment.

Cyclosporine is an alternative therpy in nephrotic children having proteinuria unresponsive to conventional treatment. The effects of sustained administration of cyclosporine in this group of patients are scarcely known. We studied 10 male children, aged from 2 years 10 months to 11 years 3 months, treated with cyclosporine over a period longer than 12 months ((X) over bar +/- SEM: 26 +/- 3 months) because of nephrotic syndrome either steroid-resistant or dependent on high doses of esteroids (4 minimal change nephropathies and 6 IgM glomerulonephritis). Ciclosporine was started at a dose of 4-5 mg/kg/day and dosages adjusted to maintain blood levels between 70 and 120 ng/ml. All children had received treatment with prednisone and cyclophosphamide. Cyclosporine therapy significantly (p < 0,001) increased the percentage of proteinuria-free time from 20.1 +/- 1.0 to 73.7 +/- 0.9%. The beneficial action on proteinuria was not associated with important undesirable clinical analytical side effects. Inverse correlation between albuminemia and hypercholesterolemia remained unchanged. Children grew better under cyclosporine treatment as shown by an increase (p < 0.01) in height Z score irom -0.29 +/- 0.34 to +0.06 +/- 0.35. This improvement was probably related to the lower cumulative prednisone dose received by the children while they were on cyclosporin (504 +/- 80 vs 199 +/- 30 mg/patient/month). Thus, sustained treatment with cyclosporin resulted in a better control of proteinuria and acceleration of growth without important toxocity, either clinical or on laboratory tests.

Growth retardation is a common manifestation of chronic renal failure in children. To gain insight into the alterations of bone growth plate of chronic uremia, a morphometric study of tibia proximal growth plate was performed in 5/6 nephrectomized rats (NX, n = 4) and sham animals (SHAM, n = 4). Toluidine blue stained sagittal sections (5-6 microns) from ethanol-fixed and methylmethacrylate-embedded tibias were analyzed. Widths (X +/- SEM) of growth plate (GPW), proliferative (PZW) and hypertrophic zones (HZW) were calculated. Results were as follows: [table: see text] Growth plate modifications in uremia are rather due to alterations in the hypertrophic than proliferative zone. This is consistent with an abnormal metabolism of condrocytes as shown by a lower mean area of extracellular matrix (EMA) per cell in the hypertrophic zone of the NX rats (0.23 vs. 0.58 microns 2).

The present study was designed in an attempt to better define the pattern of growth in five-sixths-nephrectomized rats. Male Sprague-Dawley rats underwent two-stage (days 0 and 7) five-sixths nephrectomy (NX, n = 16) or sham surgery (SHAM, n = 9). At the time of sacrifice (day 21), renal failure (CRF) of NX rats was confirmed by elevated (p < or = 0.0001) serum concentrations (X +/- SEM) of urea nitrogen (SUN) (56 +/- 5 vs. 20 +/- 1 mg/dl) and creatinine (0.7 +/- 0.04 vs. 0.4 +/- 0.02 mg/dl) and reduced SUN (0.13 +/- 0.02 vs. 0.44 +/- 0.05 ml/min/100 g) and creatinine clearances (0.23 +/- 0.02 vs. 0.58 +/- 0.05 ml/min/100 g). As shown by lower cumulative gains of weight (41 +/- 6 vs. 74 +/- 4 g) and length (5.0 +/- 0.4 vs. 6.8 +/- 0.3 cm), NX rats grew subnormally. Detailed analysis of growth data revealed: (1) In spite of being identically matched in weight and length on day 0, at day 7, NX rats already weighed less than SHAM animals (147.1 +/- 2.3 vs. 153.4 +/- 1.9 g, p = 0.03). (2) From day 7 on, daily gain of weight was lower in the NX group only on days 8 (-6.08 +/- 0.52 vs. -1.60 +/- 0.69 g/100 g body weight) and 9 (-0.41 +/- 1.73 vs. 5.18 +/- 0.63 g/100 g body weight). (3) Following the early post-second-nephrectomy period, two subgroups of NX rats were clearly differentiated according to whether or not their daily growth rate was lower than that of SHAM animals. Maintained subnormal growth rate was observed in rats with severe CRF (SUN 73 +/- 5 mg/dl, range 54-90) but not in rats having milder uremia (42 +/- 3 mg/dl, range 31-51). Thus, growth in five-sixths-nephrectomized rats should be reported based on daily weight increments (g/100 g body weight). Subnormal growth can be attributed to CRF provided SUN is at least 3 times as high as normal while growth impairment of rats with less marked reduction of renal function is likely related to transient acute renal failure and postsurgical catabolic state.

Daily nitrogen intake was estimated in 19 children, aged (mean +/- SD) 9.9 +/- 5.0 (range: 1-19) years with chronic renal insufficiency (creatinine clearance 47.1 +/- 19.3 ml/min/1.73 m2, range: 11-75) by 31 three-day prospective dietary records (NIDR) and simultaneous 24-hour urine urea excretion (NIUE). Daily nitrogen intake was 11.05 +/- 3.9 g by NIDR and 8.52 +/- 3.3 g by NIUE, and a significant correlation (r = 0.61; p = 0.0003) existed between both methods of measurement. However, the difference in nitrogen intake estimated from dietary records and from 24-hour urine collection (NIDR-NIUE) was 2.5 +/- 3.3 g, greater than the mean estimated nitrogen intake calculated from both methods, (NIDR + NIUE)/2, 95% limits of agreement being +9.1 to -4.1. Thus, NIDR and NIUE values show a good correlation in children with chronic renal insufficiency, although both methods may provide quite a different estimation in a given child.

Nutritional status was evaluated in 15 children (11 males) with moderate chronic renal failure (CRF). Two 3-day prospective dietary records, anthropometric measures and biochemical determinations were performed 3 months apart. Energy, protein, carbohydrate, fat, polyunsaturated, monounsaturated and saturated fatty acid intakes, expressed as percentages of international recommendations, were 87±14, 223±42, 73±12, 110±27, 55±31, 129±51 and 111±26%, respectively. The relative distribution of calories was 15±2% from proteins, 48±5% from carbohydrates and 37±5% from lipids. Anthropometric indices, expressed as standard deviation score, were: weight −0.50±0.8, height −0.94±1.3, growth velocity −0.61±1.8, triceps skinfold thickness −0.30±0.6, subscapular skinfold thickness −0.19±0.8, mid-arm muscle circumference 0.38±0.3 and body mass index −0.22±1.0. Serum concentrations of albumin, total protein, transferrin, IgG, IgA, IgM, C3 and C4 and blood lymphocyte counts were within normal limits. The mean serum insulin-like growth factor-I concentration, expressed as standard deviation score, as 0.74±1.5. No anthropometric or biochemical signs of malnutrition were found in children with moderate CRF. However, their dietary intake of calories and carbohydrates was low and the protein and saturated fatty acid intake excessively high.

The effects of recombinant human growth hormone administration on water, electrolyte, calcium-phosphate, carbohydrate, and lipid metabolisms of stunted children with chronic renal failure (CRF) are mostly unknown. Serum biochemical profile was investigated in Sprague-Dawley male rats with CRF, induced by 516 nephrectomy, treated with rhGH. Five groups of animals were studied: CRF (NX n = 29), CRF + rhGH treatment (NXGH, n = 12), sham-operated receiving food ad libitum (SHAMAL, n = 17), sham-operated pair-fed with NX (SPFNX, n = 16) or NXGH (SPFNXGH, n = 8) rats. Intraperitoneal rhGH was given at 10 IU/kg/day over a 13 day period following second stage nephrectomy. Serum urea nitrogen and creatinine concentrations (X +/- SEM) of NX (62 +/- 8 and 0.7 +/- 0.1 mg/dl) and NXGH (73 +/- 9 and 0.8 +/- 0.1 mg/dl) rats were higher (p = 0.0001) than those of SHAMAL (20 +/- 1 y 0.5 +/- 0.0 mg/dl). No difference were found in serum concentrations of sodium, potassium, chloride, calcium, phosphate, and triglycerides among the groups of animals. NX and NXGH rats had higher serum concentrations of CO2, alkaline phosphatase, and cholesterol than SHAMAL. These differences were diet independent because they persisted when NX and NXGH rats were compared with their SPFNX and SPFNXGH pairs receiving identical amount of food. NXGH rats were more hypercholesterolemic (139 +/- 9 mg/dl) and their glycemia was lower (155 +/- 8 mg/dl) than NX rats (120 +/- 4 and 176 +/- 4 mg/dl, p = 0.02 and 0.01, respectively). Thus, rhGH treatment aggravated hypercholesterolemia of uremic rats. This undesirable effect should be carefully monitored in the follow-up of CRF children treated with high doses of rhGH