Risk factors of calcium and urate nephrolithiasis. Role of the canalicular dysfunction in stone formation

In this review we analyze the role of exogenic and endogenic risk factors of nephrolithiasis and their link to dysfunction of renal tubules and discuss cell membrane pathology, lipid peroxidation, ischemia and hypoxia of the kidneys, as well as hormonal balance and renal innervation with regard to urine lithogenic properties. Important is the secondary character of anionic and cationic disturbances of the urine from the renal clearance of sodium. Active transport of sodium with membrane Na+-ATPase is key event for calcium, phosphates and urates reabsorption, concentration of which define the lithogenic properties of the urine. Our analysis shows that type of renal tubular dysfunction determines the stone composition, and vice versa chemical composition of stone is a key to the level of the tubular dysfunction and to the role of the different tubular structures and collective ducts in the stone formation. Perspectives of the prophylaxis and metaphylaxis of the nephrolithiasis are linked to the improvement of the function of renal tubules during the activation of lipid peroxidation, which leads to energodeficiency state, increases the oxygen metabolism, level of the energetic supply to the cells, decreases the catabolism of purines and calcium concentration in urine.