Figure 1.

Imbalance of urinary inhibitors and promotors of crystallization leading to kidney stone formation. Concentration of urinary inhibitors and promotors is influenced and controlled by both intestinal and renal transporters (GI–kidney axis). These transporters and exchangers, such as SLC26A1, are responsible for secretion and absorption. With regards to oxalate, enteral hyperabsorption but malsecretion, and/or renal hypersecretion but malabsorption leads to urinary oxalate levels exceeding supersaturation and thereby promoting crystallization and consecutive stone formation [adapted from Ref. (2)].