Podocyte dysfunction in aging--related glomerulosclerosis

We review podocyte molecular structure and function, consider the underlying mechanisms related to podocyte dysfunction and propose that podocyte dysfunction be considered in the evaluation and management of age-associated glomerulosclerosis. With aging, progressive sympathetic activation, increased intrarenal renin-angiotensin system (RAS) activity, endothelin system and oxidative stress and reduced nitric oxide (NO)-availability can damage podocytes. Apoptosis and proliferation are the principal podocyte changes following injury with the latter leading to sclerosis and loss of nephrons. Podocyte loss can be evaluated by either determining their average number in biopsed glomeruli or by estimating podocyte number or their associated molecules in urine sediment. Podocyturia may be considered a marker of active glomerular disease. Preliminary data suggest that antiadrenergic drugs, angiotensin converting enzyme (ACE) inhibitors, RAS blocking drugs, endothelin system inhibitors and reduced oxidative stress can protect podocytes. Thus podocytes appear to play an important role in the pathogenesis, evaluation and therapy of age related glomerulosclerosis.