Podocyte Hypertrophy, “Adaptation,” and “Decompensation” Associated with Glomerular Enlargement and Glomerulosclerosis in the Aging Rat

A recent report has dealt with geriatric nephrology, including epidemiology and pathophysiology of chronic kidney disease (CKD), attempting to get nephrologists to pay more attention to elderly CKD patients. The aims of this article are to summarize the morphological and functional properties of the aging kidney, and to better understand nephrology care for elderly CKD patients. The kidneys are affected by the aging process, which results in numerous effects on the renal system. In addition, the elderly population is hetereogenous - some have a decline in GFR explained by diseases that complicate aging such as arteriosclerosis with hypertension, whereas in the most of healthy adults the decline in GFR is much more modest and not inevitable. The values for normal estimated glomerular filtration rate (eGFR) in aging population have important implications for the diagnosis of CKD in the elderly. However, the MDRD equation underestimates mean eGFR by 25% and the CKD-EPI equation underestimates mean GFR by 16%. This bias may lead to misclassifying healthy older persons as having CKD. It is also still unknown whether and how age influences the predictive role of other risk factors for end-stage renal disease (ESRD) and death in referred as well as unreferred patients. The risk of ESRD was reported to be higher than the risk of death without ESRD for ages <60 years, and independent of eGFR. Proteinuria significantly increased the risk of ESRD with advancing age. In older patients on nephrology care, the risk of ESRD prevailed over mortality even when eGFR was not severely impaired. Proteinuria increases the risk of ESRD, while the predictive role of other modifiable risk factors was unchanged compared with younger patients. The decision to initiate renal replacement therapy in the elderly is complicated by more challenges than in younger patients. Calorie restriction and Klotho deficiency may be a candidate therapeutic target for attenuating kidney aging. © 2014 S. Karger AG, Basel.