Inhibition of mineralocorticoid receptor is a renoprotective effect of the 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor pitavastatin.

OBJECTIVE

The mineralocorticoid receptor has been implicated in the pathogenesis of chronic cardiorenal disease. Statins improve renal remodeling and dysfunction in patients with proteinuric kidney diseases. We aimed to clarify the beneficial effects and mechanisms of action of statins in renal insufficiency.

METHODS AND

RESULTS

Dahl salt-sensitive rats fed a high-salt diet were treated from 12 to 20 weeks of age with vehicle, the reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase inhibitor apocynin, the synthetic cathepsin inhibitor E64d, or a low or high dosage of pitavastatin (1 or 3 mg/kg daily). Rats fed a low-salt diet served as controls. Rats on the high-salt diet developed massive proteinuria and glomerulosclerosis; these changes were attenuated by both doses of pitavastatin. The amounts of mRNAs or proteins for mineralocorticoid receptor, angiotensin-converting enzyme, angiotensin II type 1 receptor (AT1R), monocyte chemoattractant protein-1, osteopontin, macrophage infiltration, and NADPH subunits (gp91phox, p22phox, and Rac1) were significantly higher in the failing kidneys of vehicle-treated rats than in the kidneys of control rats. Either dose of pitavastatin significantly attenuated these changes. These effects of pitavastatin were mimicked by those of apocynin and E64d. Pretreatment with pitavastatin and apocynin inhibited mRNA and protein of mineralocorticoid receptor induced by angiotensin II in cultured podocytes.

CONCLUSION

The beneficial effects of pitavastatin are likely attributable, at least in part, to attenuation of the mineralocorticoid receptor-dependent inflammatory mediator, matrix protein, and cathepsin expressions induced by AT1R-mediated NADPH oxidase activation in the kidneys of a salt-induced hypertensive Dahl salt-sensitive rat model.