Uric acid crystal binding to renal inner medullary collecting duct cells in primary culture.

Attachment of microcrystals to cellular membranes may be an important component in the pathophysiology of urolithiasis. This study characterizes the concentration-dependent binding of uric acid crystals to rat renal inner medullary collecting duct cells in primary culture. Collecting duct cell cultures grew as monolayers with interspersed aggregates of rounded cells. Cultures were incubated with 14C-uric acid crystals, and the crystals that bound were quantitated by adherent radioactivity. Uric acid crystal adherence demonstrated concentration dependent saturation with a 1/alpha value (maximum micrograms of crystals adhering to 1 cm2 of binding area) of 645 micrograms/cm2. The beta values (fraction of cross-sectional area which bound crystals) of uric acid (mean = 0.15) and calcium oxalate monohydrate (mean = 0.13) crystals did not differ significantly. Uric acid crystal binding was inhibited by pre-bound calcium oxalate monohydrate crystals in a concentration dependent manner. These data suggest that uric acid and calcium oxalate crystals exhibit similar binding patterns to rat renal inner medullary collecting duct cells in primary culture.