Aldosterone promotes cardiac endothelial cell proliferation in vivo

Experimentally, aldosterone in association with NaCl induces cardiac fibrosis, oxidative stress, and inflammation through mineralocorticoid receptor activation; however, the biological processes regulated by aldosterone alone in the heart remain to be identified. Mice were treated for 7 days with aldosterone, and then cardiac transcriptome was analyzed. Aldosterone regulated 60 transcripts (51 upregulated and 9 downregulated) in the heart (fold change ≥1.5, false discovery rate <0.01). To identify the biological processes modulated by aldosterone, a gene ontology analysis was performed. The majority of aldosterone-regulated genes were involved in cell division. The cardiac Ki-67 index (an index of proliferation) of aldosterone-treated mice was higher than that of nontreated mice, confirming microarray predictions. Costaining of Ki-67 with vinculin, CD68, α-smooth muscle actin, CD31, or caveolin 1 revealed that the cycling cells were essentially endothelial cells. Aldosterone-indu...