Calcium oxalate-crystal membrane interactions: Dependence on membrane lipid composition

Purpose: Urolithiasis is clearly a multifaceted process, progressing from urine supersaturation to the formation of mature renal calculi. Retention of microcrystals by the urothelium is a critical event in stone maturation. Membrane phospholipids appear to be involved in the attachment 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 composition by using a crystal-induced membranolytic assay. Results: Membrane enrichment with anionic phospholipids was found to greatly increase crystal-membrane interactions. Crystal-membrane interaction was associated with an increase in the negative charge on the RBC membrane surface. 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.