CALCIUM OXALATE-CRYSTAL MEMBRANE INTERACTIONS - DEPENDENCE ON MEMBRANE LIPID-COMPOSITION

Purpose: Urolithiasis is clearly a multifaceted process, progressing f rom urine supersaturation to the formation of mature renal calculi. Re tention of microcrystals by the urothelium is a critical event in ston e maturation. Membrane phospholipids appear to be involved in the atta chment of stone crystals to kidney epithelium. Materials and Methods: The current study quantitates crystal-membrane interactions following selective changes in the red blood cell (RBC) membrane phospholipid co mposition by using a crystal-induced membranolytic assay. Results: Mem brane enrichment with anionic phospholipids was found to greatly incre ase crystal-membrane interactions. Crystal-membrane interaction was as sociated with an increase in the negative charge on the RBC membrane s urface. Conclusions: Specific membrane compositions seem to facilitate the formation of a crystal attachment region on the RBC surface that is necessary for effective crystal attachment to the cell membrane.