title: Effect of eplerenone on hypertension-associated renal damage in rats: potential role of peroxisome proliferator activated receptor gamma (PPAR-γ).
abstract: Several factors, including mineralocorticoids, have been implicated in the renal damage associated with hypertension. Peroxisome proliferator activated receptor gamma (PPAR-γ) agonists improve renal damage associated with different pathologies. Therefore, our hypothesis was that mineralocorticoid receptor blockade ameliorates renal damage associated with hypertension and that this improvement may be mediated by PPAR-γ. Spontaneously hypertensive rats (SHR) were treated with either vehicle or eplerenone, a mineralocorticoid receptor antagonist, at two different doses: 30 and 100 mg/kg/day for 10 weeks. Age-matched Wistar Kyoto rats (WKY) were used as a normotensive reference group. SHR showed tubulointersticial fibrosis and mild tubular atrophy. These alterations were accompanied by increases in renal cortex gene expression of transforming growth factor beta (TGF-β) connective tissue growth factor (CTGF) and phosphorylated Smad2 protein levels, factors involved in the fibrotic response. Interleukin 1-beta (IL-1β) and tumor necrosis factor alpha (TNF-α) gene expression were also increased. By contrast, lysyl oxidase (LOX) expression and PPAR-γ protein levels were decreased in SHR as compared with normotensive animals. Only the high dose of eplerenone was able to reduce blood pressure and partially prevent LOX down-regulation in SHR. Both eplerenone doses significantly ameliorated interstitial fibrosis and tubular atrophy, reduced TGF-β, CTGF and cytokine gene expression, and decreased Smad2 activation, while normalizing PPAR-γ protein levels.
  
  
  CONCLUSIONS
  Mineralocorticoid receptor activation participates in hypertension-associated renal damage. This effect seems to involve stimulation of both fibrotic and inflammatory processes mediated (at least in part) by a down-regulation of PPAR-γ that can favour an up-regulation of the TGF-β/Smad signalling pathway.
authors: Department of Physiology, School of Medicine, Universidad Complutense, Madrid, Spain.
authors: M
authors: M
authors: Miana
authors: N
authors: N
authors: de Las Heras
authors: C
authors: C
authors: Rodriguez
authors: D
authors: D
authors: Sanz-Rosa
authors: B
authors: B
authors: Martin-Fernandez
authors: S
authors: S
authors: Mezzano
authors: V
authors: V
authors: Lahera
authors: J
authors: J
authors: Martinez-Gonzalez
authors: V
authors: V
authors: Cachofeiro
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D055513:Connective Tissue Growth Factor / Q000235:genetics / Q000378:metabolism; D016207:Cytokines / Q000235:genetics; D015536:Down-Regulation; D000077545:Eplerenone; D015870:Gene Expression; D006973:Hypertension / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D007672:Kidney Cortex / Q000378:metabolism / Q000503:physiopathology; D007674:Kidney Diseases / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D000451:Mineralocorticoid Receptor Antagonists; D047495:PPAR gamma / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D008249:Protein-Lysine 6-Oxidase / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D018161:Receptors, Mineralocorticoid / Q000378:metabolism; D015398:Signal Transduction; D051899:Smad2 Protein / Q000378:metabolism; D013148:Spironolactone / Q000031:analogs & derivatives* / Q000494:pharmacology; D015854:Up-Regulation
chemical_list: D016207:Cytokines; D000451:Mineralocorticoid Receptor Antagonists; D047495:PPAR gamma; D018161:Receptors, Mineralocorticoid; D051899:Smad2 Protein; C497784:Smad2 protein, rat; D055513:Connective Tissue Growth Factor; D013148:Spironolactone; D000077545:Eplerenone; D008249:Protein-Lysine 6-Oxidase