Epiphyseal growth plate growth hormone receptor signaling is decreased in chronic kidney disease-related growth retardation

Kidney Int. 2013 Nov;84(5):940-9. doi: 10.1038/ki.2013.196. Epub 2013 May 29.

Abstract

Linear growth retardation in children with chronic kidney disease (CKD) has been ascribed to insensitivity to growth hormone. This resistance state has been attributed to impaired growth hormone signaling through the JAK2/STAT5 pathway in liver and skeletal muscle leading to reduced insulin-like growth factor-I (IGF-I). Here we determine whether systemic and growth plate alterations in growth hormone signaling contribute to CKD-induced linear growth retardation using partially nephrectomized and pair-fed control 20-day-old rats. Serum growth hormone did not change in rats with CKD, yet serum IGF-I levels were decreased and growth retarded. The tibial growth plate hypertrophic zone was wider and vascularization at the primary ossification center was reduced in CKD. This was associated with a decrease in growth plate vascular endothelial growth factor (VEGF) mRNA and immunostainable VEGF and IGF-I levels. Growth plate growth hormone receptor and STAT5 protein levels were unchanged, while JAK2 was reduced. Despite comparable growth hormone and growth hormone receptor levels in CKD and control rats, relative STAT5 phosphorylation was significantly depressed in CKD. Of note, the mRNA of SOCS2, an inhibitor of growth hormone signaling, was increased. Thus, linear growth impairment in CKD can in part be explained by impaired long bone growth plate growth hormone receptor signaling through the JAK2/STAT5 pathway, an abnormality that may be caused by an increase in SOCS2 expression.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Disease Models, Animal
  • Gene Expression Regulation
  • Growth Disorders / etiology*
  • Growth Disorders / genetics
  • Growth Disorders / metabolism
  • Growth Disorders / physiopathology
  • Growth Hormone / blood
  • Growth Hormone / metabolism*
  • Growth Plate / blood supply
  • Growth Plate / growth & development
  • Growth Plate / metabolism*
  • Insulin-Like Growth Factor I / metabolism
  • Janus Kinase 2 / metabolism
  • Kidney / physiopathology
  • Male
  • Nephrectomy
  • Phosphorylation
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Renal Insufficiency, Chronic / complications*
  • Renal Insufficiency, Chronic / etiology
  • Renal Insufficiency, Chronic / genetics
  • Renal Insufficiency, Chronic / metabolism
  • Renal Insufficiency, Chronic / physiopathology
  • STAT5 Transcription Factor / metabolism
  • Signal Transduction*
  • Suppressor of Cytokine Signaling Proteins / genetics
  • Suppressor of Cytokine Signaling Proteins / metabolism
  • Tibia / blood supply
  • Tibia / growth & development
  • Tibia / metabolism*
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism

Substances

  • RNA, Messenger
  • STAT5 Transcription Factor
  • Socs2 protein, rat
  • Suppressor of Cytokine Signaling Proteins
  • Vascular Endothelial Growth Factor A
  • insulin-like growth factor-1, rat
  • vascular endothelial growth factor A, rat
  • Insulin-Like Growth Factor I
  • Growth Hormone
  • Jak2 protein, rat
  • Janus Kinase 2