Aldosterone induces mesangial cell apoptosis both in vivo and in vitro

Area of Science:

• Nephrology
• Endocrinology
• Cell Biology

Background:

• Aldosterone is implicated in renal failure progression beyond its hemodynamic actions.
• Understanding aldosterone's direct cellular effects on the kidney is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the direct impact of aldosterone on human mesangial cell (MC) apoptosis and proliferation.
• To evaluate the efficacy of aldosterone antagonists and antioxidants in mitigating aldosterone-induced MC apoptosis in vitro and in vivo.

Main Methods:

• Human mesangial cells were treated with aldosterone to assess apoptosis and mitogenesis.
• In vivo studies involved aldosterone infusion in rats, with measurements of blood pressure, albuminuria, and kidney cell apoptosis.
• Mineralocorticoid receptor antagonists (spironolactone, eplerenone), antioxidants, and free radical scavengers were used to block aldosterone effects.

Main Results:

• Aldosterone induced both apoptotic and mitogenic effects on human mesangial cells in a dose- and time-dependent manner.
• Aldosterone promoted MC apoptosis by enhancing phospho-Bad dephosphorylation and cytosolic cytochrome c accumulation.
• In vivo, aldosterone infusion increased systolic blood pressure, albuminuria, and mesangial cell apoptosis in rats, effects inhibited by eplerenone.

Conclusions:

• Aldosterone directly induces mesangial cell apoptosis, contributing to renal failure progression independently of hemodynamic changes.
• Mineralocorticoid receptor antagonists and antioxidants show potential in preventing aldosterone-mediated kidney damage.
• Targeting aldosterone's direct cellular effects offers a promising therapeutic strategy for renal protection.