Characterization of the Antilithiatic Proteins from Terminalia Arjuna and Evaluation of their Cytoprotective Role on Oxalate Induced Renal Tubular Epithelial Cell Injury

Abstract

Kidney stones are one of the oldest and painful multifactorial disorder caused by metabolic abnormalities influencing the composition of body fluids and urine. Kidney stones are tiny hard masses of minerals that can be lodged in any part of the urinary tract e.g. kidneys bladder urethra and ureter yet during last century interestingly the incidence of its occurrence has shifted from the lower bladder and ureter to the upper kidneys urinary tract. Calcium oxalate CaOx has been shown to be the main component of about two third of all urinary calculi and exist in two forms as calcium oxalate monohydrate COM or Whewellite and calcium oxalate dihydrate COD or Weddellite. COM the thermodynamically most stable form is observed more frequently in clinical stones than COD and has greater affinity for renal tubular cells thus responsible for the formation of stones in the kidney. COM has been found to initiate mineralization followed by the deposition of COD on it. In addition to calcium oxalate urinary stones have also been found to contain phosphates uric acid and magnesium ammonium phosphates with apatite and struvites predominating. The mechanisms involved in the formation of urinary stones are not fully understood but it is generally agreed that urinary lithiasis is a multifaceted process involving events leading to supersaturation of urine crystal nucleation aggregation and growth of insoluble particles. Urine is always supersaturated with common stone forming minerals however the crystallization inhibiting capacity of urine does not allow urolithiasis to happen in most of the individuals whereas this natural inhibition is in deficit in stone formers. Also CaOx crystal cell interaction plays a crucial role in the formation of CaOx kidney stones. The retention of microcrystals by the urothelium is considered an essential critical step in the growth of renal calculi. Moreover the binding of crystals to kidney epithelial cells in culture has been shown to be enhanced by previous cell injury. Several in vitro studies hav