580 SOMATOMEDIN-C LEVELS IN CHILDREN WITH CHRONIC INFLAMMATORY BOWEL DISEASE (IBD)

Abstract

This study was designed to determine whether somatomedin-C (SM-C) levels were different in growth-impaired and normally-growing children with IBD and whether SM-C levels in growth-retarded children change as growth velocity improves. Diminished caloric intake is a common feature of IBD and experimental reduction of nutrient intake in rats lowers circulating SM levels. Low SM values have also been reported in children with protein-calorie malnutrition, anorexia nervosa and chronic renal failure. Plasma SM-C was measured by radioimmunoassay in 31 children with IBD. Thirteen of these pts had impaired growth velocity (GV) by Tanner standards and were compared with 19 pts with normal GV. Seven of the growth-retarded pts had SM-C levels repeated during a period of normal growth. Medical therapy was standard including alternate-day prednisone in 11 pts. No pt. received prednisone within 24 hrs of measuring SM-C. Somatomedin-C levels were 1.06 ± 0.14 units/ml (mean ± SEM) in the growth-impaired group and 3.29 ± 0.52 in the normally growing group (p<0.01). SM-C levels in the 7 growth-retarded pts who were studied sequentially increased from 1.26 ± 0.26 to 2.3 ± 0.29 during periods of improved growth velocity (p<0.02). There was no depression of SM-C in pts receiving alternate-day prednisone. These differences cannot be explained by differences in age, bone age, or pubertal stage. This study suggests that growth retardation in IBD is accompanied by reduced SM-C levels, which increase as growth improves.