Tartaric acid induces toxicity in Madin-Darby canine kidney cells, but not human kidney-2 cells in vitro, and is prevented by organic anion transporter inhibition and human OAT-4 transfection.

OBJECTIVES

To evaluate the effect of tartaric acid (TTA) on Madin-Darby canine kidney (MDCK) cells compared to human kidney (HK)-2 cells. Secondarily, to evaluate the effects of probenecid, an organic anion transporter (OAT)-1 inhibitor, as well as human (h)OAT-4 transfection into MDCK cells to prevent TTA-induced cytotoxicity through decreasing accumulation via OAT-1 uptake inhibition or increasing OAT-4-mediated TTA efflux.

DESIGN

Seventy-two-hour TTA concentration response and inhibitor studies in immortalized cell lines.

SETTING

School of Pharmacy biomedical research laboratory and tissue culture facility.

ANIMALS/SAMPLES: MDCK and HK-2 immortalized cell lines.

INTERVENTIONS

Both cell lines were treated with increasing concentrations of TTA for 72 hours. Additionally, MDCK cells were co-incubated with TTA and increasing concentrations of probenecid or had been transfected with hOAT-4 and subsequently treated with TTA for 72 hours.

MEASUREMENTS AND MAIN RESULTS

Media and samples were collected and lactate dehydrogenase (LDH) release was measured. LDH release was measured to assess TTA-induced cytotoxicity after 72 hours. LDH was not significantly increased in the HK-2 cells at any concentration but was significantly increased in the MDCK cells from 10 to 100 mM. LDH concentrations were significantly decreased (61%) in MDCK cells incubated with 50 mM TTA and probenecid when compared to TTA alone. hOAT-4 MDCK cell transfection also significantly reduced LDH release (57%) when comparing the transfected MDCK cells to the nontransfected MDCK cells treated with 50 mM TTA.

CONCLUSIONS

TTA is a species-specific nephrotoxicant in dogs due to an interspecies difference in OAT-4 expression. Inhibiting TTA uptake in MDCK cells in vitro using the OAT-specific inhibitor, probenecid, prevents TTA-induced cytotoxicity.