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- Title
Pericryptal Myofibroblast Growth in Rat Descending Colon Induced by Low-Sodium Diets Is Mediated by Aldosterone and not by Angiotensin II.
- Authors
Cristià, E.; Afzal-Ahmed, I.; Pérez-Bosque, A.; Amat, C.; Naftalin, R.J.; Moretó, M.
- Abstract
Pericryptal myofibroblast growth in descending colonic crypts correlates with the activation of the renin-angiotensin-aldosterone system. Earlier work showed that during the transition from a high-Na+ (HS) to low-Na+ (LS) diet there are changes in the colonic crypt wall and pericryptal sheath. As LS diet increases both aldosterone and angiotensin II, the aim here was to determine their individual contributions to the trophic changes in colonic crypts. Experiments were conducted on control and adrenalectomized Sprague-Dawley rats fed an HS diet and then switched to LS diet for 3 days and supplemented with aldosterone or angiotensin II. The actions of the angiotensin-converting enzyme inhibitor captopril, the angiotensin receptor antagonist losartan and the aldosterone antagonist spironolactone on extracellular matrix proteins, claudin 4 and E-cadherin myofibroblast proteins, α-smooth muscle actin (α-SMA) and OB-cadherin (cadherin 11), angiotensin type 1 and TGFβr1 membrane receptors were determined by immunolocalization in fixed distal colonic mucosa. The LS diet or aldosterone supplementation following ADX in HS or LS increased extracellular matrix, membrane receptors and myofibroblast proteins, but angiotensin alone had no trophic effect on α-SMA. These results show that aldosterone stimulates myofibroblast growth in the distal colon independently of dietary Na+ intake and of angiotensin levels. This stimulus could be a genomic response or secondary to stretch of the pericryptal sheath myofibroblasts accompanying enhanced rates of crypt fluid absorption.
- Subjects
ALDOSTERONE; ANGIOTENSIN II; MYOFIBROBLASTS; FIBROSIS; MINERALOCORTICOIDS; COLLAGEN diseases
- Publication
Journal of Membrane Biology, 2005, Vol 206, Issue 1, p53
- ISSN
0022-2631
- Publication type
Article
- DOI
10.1007/s00232-005-0773-4