Structural and physiological changes of the kidney with age and its impact on chronic conditions and COVID-19

The kidney is an essential organ that removes waste products, balances the body's fluids, releases hormones that regulate blood pressure, produces an active form of vitamin D, promotes healthy bones, and controls the production of red blood cells. Structural and functional abnormalities occur in kidney with age. Alterations in kidney structure are based on physiological functions and environmental pressures. Variations in its structure across vertebrates are primarily due to the nature of alterations in number, complexity, arrangement, and location of the kidney tubules. Globally, individuals aged 65 and older are part of the fastest expanding population demographic, and as a result, a greater number of older patients are receiving a diagnosis of impaired renal function. The purpose of our mini-review is to summarize recent findings of the structural and functional differences between the normal and aging kidney, examine the evolutionary biology of the kidney across species, and demonstrate the role of aging in conditions such as diabetes, chronic kidney disease, and hypertension, along with their impact on SARS-CoV-2. Additional aims include discussing the potential therapeutic strategies to treat aged individuals with kidney health issues and how the impact of a healthy lifestyle, diet, and exercise can improve health conditions with aged kidneys.