Intestinal inflammation-induced growth retardation acts through IL-6 in rats and depends on the -174 IL-6 G/C polymorphism in children

Proc Natl Acad Sci U S A. 2005 Sep 13;102(37):13260-5. doi: 10.1073/pnas.0503589102. Epub 2005 Sep 6.

Abstract

Inflammatory diseases frequently impair linear growth. Crohn's disease inhibits growth in up to one third of affected children. In rats with trinitrobenzenesulphonic acid-induced colitis, 40% of growth impairment is attributable to inflammation, with the rest being due to undernutrition. In transgenic mice without inflammation, raised IL-6 retards growth, suppressing insulin-like growth factor (IGF)-I. We hypothesized that IL-6, induced by intestinal inflammation, suppresses growth and inhibits IGF-I expression. Therefore, an anti-IL-6 Ab was given to rats with trinitrobenzene-sulphonic acid colitis. The Ab did not improve nutrient intake or decrease inflammation compared with untreated disease controls, but it significantly restored linear growth (P = 0.023) and increased IGF-I (P = 0.05). In humans, the IL-6 -174 G/C promoter polymorphism affects IL-6 transcription, with the GG genotype inducing the greatest IL-6 levels. Because IL-6 is increased in Crohn's disease, we further hypothesized that growth failure would vary with the IL-6 -174 genotype. At diagnosis, among 153 children with Crohn's disease, those with the IL-6 GG genotype were more growth-retarded than those with the GC or CC genotypes (height SD score, -0.51 vs. -0.10; P = 0.031). Also, the patients with the IL-6 GG genotype had higher circulating levels of C-reactive protein, an IL-6-induced product (36 vs. 18 mg/dl, P = 0.028). However, their risk of developing Crohn's disease was similar to other genotypes when compared with 351 healthy controls (P = 0.7). Thus, the IL-6 -174 genotype mediates growth failure in children with Crohn's disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies / administration & dosage
  • Antibodies / pharmacology
  • Case-Control Studies
  • Child
  • Colitis / chemically induced
  • Colitis / drug therapy
  • Crohn Disease / genetics
  • Disease Models, Animal
  • Genotype
  • Growth Disorders / etiology*
  • Humans
  • Inflammation / etiology
  • Inflammation / physiopathology*
  • Insulin-Like Growth Factor I / genetics
  • Interleukin-6 / genetics
  • Interleukin-6 / immunology
  • Interleukin-6 / physiology*
  • Intestinal Diseases / drug therapy
  • Intestinal Diseases / etiology*
  • Intestinal Diseases / genetics
  • Polymorphism, Single Nucleotide*
  • Promoter Regions, Genetic
  • Rats
  • Rats, Wistar
  • Trinitrobenzenesulfonic Acid

Substances

  • Antibodies
  • Interleukin-6
  • Insulin-Like Growth Factor I
  • Trinitrobenzenesulfonic Acid