Renal Metabolism

The role of Sirt1 in renal rejuvenation and resistance to stress

“…Hypoxia also exists in the renal medulla, but whereas the renal cortex requires aging or chronic kidney disease to become hypoxic, hypoxia is a constant and defining feature of the medulla in the healthy kidney (1,(12)(13)(14). The renal medulla critically contributes to overall renal function, as it reabsorbs substantial amounts of filtered sodium, regulates water excretion, and assists in the maintenance of normotension.…”

“…The renal medulla critically contributes to overall renal function, as it reabsorbs substantial amounts of filtered sodium, regulates water excretion, and assists in the maintenance of normotension. Such functioning of the medulla occurs despite the presence of hypoxia and other conditions that threaten cell viability, and these include a meager blood supply, increased ammonia concentrations, substantial ROS generation by a metabolically active thick ascending limb, and markedly increased interstitial osmolality (1,12,13). Interstitial hyperosmolality, due to the high interstitial concentrations of sodium chloride and urea, may perturb cellular structure and function, in part, by promoting the generation of ROS.…”

“…Ang II has been implicated in the pathophysiology of atherosclerosis and heart failure (HF) due to its role in regulating multiple renal and cardiovascular functions, including salt/water retention, vasoconstriction, aldosterone secretion, cardiac hypertrophy, thrombosis, fibrosis, and others (1). In the classical renin-angiotensin system (RAS), angiotensinogen (AGT) produced in the liver enters the circulation, where it is cleaved by renin produced in the kidneys to form Ang I. Ang I is converted to Ang II by angiotensin-converting enzyme (ACE) bound to vascular endothelial cells.…”