Renal Effects and Underlying Molecular Mechanisms of Long-Term Salt Content Diets in Spontaneously Hypertensive Rats

Author(s):Show less -

Machado Berger, Rebeca Caldeira ^[1] ; Vassallo, Paula Frizera ^[1] ; Crajoinas, Renato de Oliveira ^[2] ; Oliveira, Marilene Luzia ^[3] ; Martins, Flavia Leticia ^[2] ; Nogueira, Breno Valentim ^[4] ; Motta-Santos, Daisy ^[2] ; Araujo, Isabella Binotti ^[4] ; Forechi, Ludimila ^[1] ; Costa Girardi, Adriana Castello ^[2] ; Souza Santos, Robson Augusto ^[3] ; Mill, Jose Geraldo ^[1]

Affiliation

^[1] Univ Fed Espirito Santo, Dept Physiol Sci, Vitoria, ES - Brazil

^[2] Univ Sao Paulo, Sch Med, Heart Inst InCor, Sao Paulo, SP - Brazil

^[3] Univ Fed Minas Gerais, Dept Physiol & Biophys, Belo Horizonte, MG - Brazil

^[4] Univ Fed Espirito Santo, Dept Morphol, Vitoria, ES - Brazil

• Document type: Journal article
• Source: PLoS One; v. 10, n. 10 OCT 23 2015.
• Web of Science Citations: 7

Abstract

Several evidences have shown that salt excess is an important determinant of cardiovascular and renal derangement in hypertension. The present study aimed to investigate the renal effects of chronic high or low salt intake in the context of hypertension and to elucidate the molecular mechanisms underlying such effects. To this end, newly weaned male SHR were fed with diets only differing in NaCl content: normal salt (NS: 0.3%), low salt (LS: 0.03%), and high salt diet (HS: 3%) until 7 months of age. Analysis of renal function, morphology, and evaluation of the expression of the main molecular components involved in the renal handling of albumin, including podocyte slit-diaphragm proteins and proximal tubule endocytic receptors were performed. The relationship between diets and the balance of the renal angiotensin-converting enzyme (ACE) and ACE2 enzymes was also examined. HS produced glomerular hypertrophy and decreased ACE2 and nephrin expressions, loss of morphological integrity of the podocyte processes, and increased proteinuria, characterized by loss of albumin and high molecular weight proteins. Conversely, severe hypertension was attenuated and renal dysfunction was prevented by LS since proteinuria was much lower than in the NS SHRs. This was associated with a decrease in kidney ACE/ ACE2 protein and activity ratio and increased cubilin renal expression. Taken together, these results suggest that LS attenuates hypertension progression in SHRs and preserves renal function. The mechanisms partially explaining these findings include modulation of the intrarenal ACE/ACE2 balance and the increased cubilin expression. Importantly, HS worsens hypertensive kidney injury and decreases the expression nephrin, a key component of the slit diaphragm. (AU)

• FAPESP's process: 13/10619-8 - Dipeptidyl peptidase IV as a potential target for the therapy of heart failure
• Grantee: Adriana Castello Costa Girardi
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/10146-0 - Molecular mechanisms of regulation of the proximal tubular function in hypertension
• Grantee: Adriana Castello Costa Girardi
• Support Opportunities: Regular Research Grants