Uteroplacental insufficiency alters nephrogenesis and downregulates cyclooxygenase-2 expression in a model of IUGR with adult-onset hypertension

Am J Physiol Regul Integr Comp Physiol. 2007 May;292(5):R1943-55. doi: 10.1152/ajpregu.00558.2006. Epub 2007 Feb 1.

Abstract

Clinical and animal studies indicate that intrauterine growth restriction (IUGR) following uteroplacental insufficiency (UPI) reduces nephron number and predisposes toward renal insufficiency early in life and increased risk of adult-onset hypertension. In this study, we hypothesized that the inducible enzyme cyclooxygenase-2 (COX-2), a pivotal protein in nephrogenesis, constitutes a mechanism through which UPI and subsequent glucocorticoid overexposure can decrease nephron number. We further hypothesized that UPI downregulates the key enzyme 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), which converts corticosterone to inert 11-dehydrocorticosterone, thereby protecting both the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR) from the actions of corticosterone. Following bilateral uterine ligation on the pregnant rat, UPI significantly decreased renal COX-2, 11beta-HSD2, and GR mRNA and protein levels, but upregulated expression of MR at birth. At day 21 of life, 11beta-HSD2, GR, and also MR mRNA and protein levels were downregulated. UPI did not affect blood pressures (BP) at day 21 of life but significantly increased systolic BP in both genders at day 140. We conclude that in our animal model, UPI decreases fetal COX-2 expression during a period of active nephrogenesis in the IUGR rat, which is also characterized by decreased nephron number and adult-onset hypertension.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 11-beta-Hydroxysteroid Dehydrogenase Type 2 / genetics
  • 11-beta-Hydroxysteroid Dehydrogenase Type 2 / metabolism
  • Aging
  • Animals
  • Cyclooxygenase 2 / genetics
  • Cyclooxygenase 2 / metabolism*
  • Down-Regulation
  • Female
  • Fetal Growth Retardation*
  • Gene Expression Regulation, Developmental / physiology
  • Hypertension*
  • Kidney / growth & development*
  • Kidney / pathology
  • Placental Circulation / physiology*
  • Placental Insufficiency / metabolism*
  • Pregnancy
  • RNA, Messenger / metabolism
  • Rats
  • Receptors, Glucocorticoid / genetics
  • Receptors, Glucocorticoid / metabolism
  • Receptors, Mineralocorticoid / genetics
  • Receptors, Mineralocorticoid / metabolism
  • Sex Characteristics

Substances

  • RNA, Messenger
  • Receptors, Glucocorticoid
  • Receptors, Mineralocorticoid
  • 11-beta-Hydroxysteroid Dehydrogenase Type 2
  • Cyclooxygenase 2
  • Ptgs2 protein, rat