Renal tubular cells undergo apoptosis when exposed to uric acid and calcium oxalate crystals

Calcium oxalate monohydrate crystals (COMC) and uric acid crystals (UAC) are endocytosed by renal tubular epithelial cells (RTEC). We studied whether these crystals could also induce programmed cell death (apoptosis) which may cause release of endocytosed crystals either into the tubular lumen or into the interstitium. RTEC from the opossum proximal tubule (OK cells) were grown in RPMI media until subconfluent. growth arrested for 48 hours, and incubated with 10 μgr/ml COMC and 10 μgr/ml UAC for 24 hours. We concluded that COMC and UAC induce apoptosis of RTEC. This may be of pathogenetic importance not only for interstitial scarring (release into interstitium) but also for crystal growth and stone formation (release into tubular lumen)