Renal and blood pressure phenotype in 18-mo-old bradykinin B2R(-/-)CRD mice

Am J Physiol Regul Integr Comp Physiol. 2003 Oct;285(4):R782-90. doi: 10.1152/ajpregu.00133.2003. Epub 2003 Jun 12.

Abstract

Aberrant gene-environment interactions are implicated in the pathogenesis of congenital renal dysgenesis (CRD), a leading cause of renal failure in infants and children. We have recently developed an animal model of CRD that is caused by gestational salt stress (5% NaCl diet; HS) of bradykinin B2R null mice [B2R(-/-)CRD; El-Dahr SS, Harrison-Bernard LM, Dipp S, Yosipiv IV, and Meleg-Smith S. Physiol Genomics 3: 121-131, 2000.]. Developing B2R(-/-)CRD mice exhibit tubular and glomerular cysts, stromal expansion, and loss of corticomedullary differentiation. In addition, B2R(-/-)CRD mice exhibit transient hypertension from 2 to 4 mo of age. The present study was designed to determine the long-term consequences of CRD on renal morphology and salt sensitivity of blood pressure in B2R(-/-)CRD mice. One-year- and 18-mo-old B2R(-/-)CRD mice exhibited stunted renal growth, glomerular cystic abnormalities, and collecting duct ectasia. Moreover, tumors of mesenchymal cell origin emerged in the dysplastic kidneys of 90% of 1-yr-old and 100% of 18-mo-old B2R(-/-)CRD mice but not in age-matched B2R(-/-) or wild-type mice. When challenged with an HS diet, 18-mo-old B2R(-/-)CRD exhibited a significant rise in systolic and diastolic blood pressures and more pronounced natriuresis and diuresis compared with salt-loaded 18-mo-old wild-type mice. Kidney aquaporin-2 expression was decreased by 50%, whereas renin, ANG type 1 receptor, and Na+-K+-ATPase levels were not different in B2R(-/-)CRD mice compared with controls. In conclusion, this study demonstrates that B2R(-/-)CRD mice exhibit permanent phenotypic and functional abnormalities in renal growth and differentiation. This novel model of human disease links gene-environment interactions with renal development and blood pressure homeostasis.

Publication types

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

MeSH terms

  • Anesthesia
  • Animals
  • Aquaporin 2
  • Aquaporin 6
  • Aquaporins / metabolism
  • Blood Pressure / physiology*
  • Disease Models, Animal
  • Diuresis / physiology
  • Female
  • Kidney / abnormalities*
  • Kidney / pathology
  • Kidney / physiology*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • Natriuresis / physiology
  • Phenotype
  • Potassium / urine
  • Receptor, Angiotensin, Type 1
  • Receptor, Bradykinin B2
  • Receptors, Angiotensin / metabolism
  • Receptors, Bradykinin / genetics*
  • Renin / metabolism
  • Sodium / urine
  • Sodium Chloride, Dietary / pharmacology
  • Sodium-Potassium-Exchanging ATPase / metabolism

Substances

  • Aqp2 protein, mouse
  • Aquaporin 2
  • Aquaporin 6
  • Aquaporins
  • Receptor, Angiotensin, Type 1
  • Receptor, Bradykinin B2
  • Receptors, Angiotensin
  • Receptors, Bradykinin
  • Sodium Chloride, Dietary
  • Sodium
  • Renin
  • Sodium-Potassium-Exchanging ATPase
  • Potassium