title: Alterations in MDCK and LLC-PK1 cells exposed to oxalate and calcium oxalate monohydrate crystals.
abstract: Structural analysis of human kidney stones reveals the presence of cellular membranes and other cell fragments. Experimentally, calcium oxalate crystallization is facilitated when an exogenous nephrotoxin is given with ethylene glycol, thus providing cellular degradation products to act as heterogeneous nuclei. In this report, we tested whether oxalate alone could act as a cell toxin capable of producing damaged cells without the presence of an exogenous agent. Cultured LLC-PK1 and MDCK cells, when exposed to 1.0 mmol KOx, a concentration at the limit of metastability for calcium oxalate nucleation, were severely damaged as measured by specific lactate dehydrogenase (LDH) release in the spent media and by trypan blue exclusion. This effect was magnified by the addition of pre-formed calcium oxalate monohydrate crystals; the injury was significantly amplified when compared to exposure to oxalate alone. Scanning electron microscopy studies illustrated attachment of crystals to cells with loss of cell-to-cell and cell-to-substrate contact, as cells were released from the monolayer. In both oxalate and combined crystal-oxalate studies, more cells were released from the monolayer and exhibited considerably more damage when compared to controls. Oxalate, at the limit of metastability for calcium oxalate, is a cell toxin and can produce cellular degradation products. This effect is increased significantly by the addition of calcium oxalate monohydrate crystals.
authors.affiliation: Department of Pathology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville 32610, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Hackett
authors.forename: P N
authors.initials: PN
authors.lastname: Shevock
authors.forename: S R
authors.initials: SR
authors.lastname: Khan
mesh_terms: D000818:Animals; D002129:Calcium Oxalate / Q000737:chemistry / Q000633:toxicity*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003460:Crystallization; D004285:Dogs; D006801:Humans; D007668:Kidney / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure; D007669:Kidney Calculi / Q000737:chemistry / Q000209:etiology / Q000473:pathology; D018374:LLC-PK1 Cells; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D010070:Oxalates / Q000737:chemistry / Q000633:toxicity*; D019815:Oxalic Acid; D013552:Swine
chemical_list: D010070:Oxalates; D002129:Calcium Oxalate; D019815:Oxalic Acid