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Downregulation of renal TRPM7 and increased inflammation and fibrosis in aldosterone-infused mice: effects of magnesium.
- Source :
- Hypertension (0194911X); Apr2008, Vol. 51 Issue 4, p915-921, 7p, 4 Diagrams, 2 Charts, 3 Graphs
- Publication Year :
- 2008
-
Abstract
- Hyperaldosteronism is associated with hypertension, cardiovascular fibrosis, and electrolyte disturbances, including hypomagnesemia. Mechanisms underlying aldosterone-mediated Mg(2+) changes are unclear, but the novel Mg(2+) transporters TRPM6 and TRPM7 may be important. We examined whether aldosterone influences renal TRPM6/7 and the TRPM7 downstream target annexin-1 and tested the hypothesis that Mg(2+) administration ameliorates aldosterone-induced cardiovascular and renal injury and prevents aldosterone-associated hypertension. C57B6 mice were studied (12 weeks, n=8 to 9/group); (1) control group (0.2% dietary Mg(2+)), (2) Mg(2+) group (0.75% dietary Mg(2+)), (3) aldosterone group (Aldo, 400 microg/kg/min and 0.9% NaCl drinking water), and (4) Aldo+Mg(2+) group. Blood pressure was unaltered by aldosterone and was similar in all groups throughout the experiment. Serum Na(+) was increased and serum K(+) and Mg(2+) decreased in the Aldo group. Aldo mice had hypomagnesuria and proteinuria, and renal, cardiac, and aortic fibrosis, which were normalized by Mg(2+) supplementation. Renal and cardiovascular expression of interleukin-6, VCAM1 and COX2 was increased in the Aldo group. Magnesium attenuated renal and cardiac interleukin-6 content and decreased renal VCAM1 and cardiac COX2 expression (P<0.05). Aldosterone decreased expression of renal TRPM7 and the downstream target annexin-1 (P<0.05) without effect on TRPM6. Whereas Mg(2+) increased mRNA expression of TRPM6 and TRPM7, it had no effect on TRPM7 and annexin-1 protein content. Our data demonstrate that aldosterone mediates blood pressure-independent renal and cardiovascular fibrosis and inflammation through Mg(2+)-sensitive pathways. We suggest that altered Mg(2+) metabolism in hyperaldosteronism may relate to TRPM7 downregulation and that Mg(2+) protects against cardiovascular and renal damaging actions of aldosterone. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 0194911X
- Volume :
- 51
- Issue :
- 4
- Database :
- Supplemental Index
- Journal :
- Hypertension (0194911X)
- Publication Type :
- Academic Journal
- Accession number :
- 31876801
- Full Text :
- https://doi.org/10.1161/HYPERTENSIONAHA.107.100339