Microvascular network remodeling in dura mater of ovariectomized pigs: role for angiopoietin-1 in estrogen-dependent control of vascular stability

Am J Physiol Heart Circ Physiol. 2007 Aug;293(2):H1131-7. doi: 10.1152/ajpheart.01156.2006. Epub 2007 May 11.

Abstract

Estrogen is a key regulator of vascular responses and angioadaptation in multiple organs and tissues, including brain. However, the consequences of a loss of ovarian steroid hormone secretion on the status of microvascular networks in brain and meninges are largely unknown. Here, using the perfused dura mater model coupled with high-resolution digital epifluorescence and laser scanning confocal microscopy and computer-assisted morphometric analysis, we demonstrate that cessation of ovarian hormone production causes dramatic vascular remodeling in meningeal microvascular networks characterized by a threefold decrease in microvessel density and capillary rarefaction and an almost fourfold increase in vascular permeability. These changes were accompanied by a significant decrease in angiopoietin-1 (Ang-1) expression and Ang-1/Tie-2 ratio (1.4-fold, P < 0.01, and 1.5-fold, P < 0.05, respectively) in ovariectomized animals compared with intact females, but no changes were detected in the expression of estrogen receptors (ER)-alpha and -beta. We conclude that estrogen-dependent control of Ang-1 expression plays an important role in stabilizing meningeal microvessel and maintaining healthy microvascular networks.

Publication types

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

MeSH terms

  • Angiopoietin-1 / metabolism*
  • Animals
  • Capillary Permeability*
  • Down-Regulation
  • Dura Mater / blood supply*
  • Estrogens / deficiency
  • Estrogens / metabolism*
  • Female
  • Image Interpretation, Computer-Assisted
  • Microcirculation / metabolism
  • Microcirculation / pathology
  • Microscopy, Confocal
  • Microscopy, Fluorescence
  • Neovascularization, Physiologic*
  • Ovariectomy*
  • Receptor, TIE-2 / metabolism
  • Receptors, Estrogen / metabolism
  • Signal Transduction*
  • Swine
  • Swine, Miniature
  • Time Factors

Substances

  • Angiopoietin-1
  • Estrogens
  • Receptors, Estrogen
  • Receptor, TIE-2