Face-selective adhesion of calcium oxalate dihydrate crystals to renal epithelial cells

The interaction between the most common urinary crystal, calcium oxalate dihydrate (COD) and the surface of monkey renal epithelial cells of the BSC- 1 line was investigated. The {100} face of exogenous COD crystals bound selectively and rapidly to the kidney cell surface. Cellular processes extended preferentially over the {100} face initially, and then progressively covered the crystal so that by 24 hours some crystals were observed beneath the plasma membrane. When nucleated from solution onto the surface of the cell monolayer, COD crystals oriented preferentially so that their {100} face were in direct contact with the cell surface. In contrast, when siliconized glass was used as a substrate, nucleated COD crystals oriented randomly. Therefore, structures on the apical surface of renal tubular cells that mediate a stereospecific interaction with the molecular array presented by the {100} face of a COD crystal may be important determinants of crystal adhesion that could contribute to crystal retention and formation of kidney stones.