P0544INHIBITION OF 15-HYDROXYPROSTAGLANDIN DEHYDROGENASE (15-PGDH) PROTECTS MICE AGAINST CONTRAST-INDUCED ACUTE KIDNEY INJURY

Abstract Background and Aims Although the mechanism of contrast-induced acute kidney injury (CI-AKI) is not fully known, the imbalance of vasoconstrictive and vasodilative mediators plays a major role. Prostaglandin E2 (PGE2) is one of the vasodilators involved in this process. Inhibition of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) causes elevation of PGE2 level in tissue by delaying the rapid degradation of PGE2 by the enzyme. We tested the hypothesis that the 15-PGE2 inhibitor would protect against CI-AKI in a mouse model and attempted to elucidate the mechanism involved. Method 10-week aged male C57/BL6 Mice were injected with 10gI/kg of iodixanol by tail vein. Renal blood flow measurement, right nephrectomy, and blood sampling were taken at 48 hours after iodixanol injection. The 15-PGDH inhibitor was injected before and after iodixanol administration. Plasma creatinine, NGAL, KIM-1 were measured as biomarkers for renal function. Histological evaluation was analyzed by the necrosis scoring system and TUNEL assay. Arteriolar area of outer medulla was analyzed by α-smooth muscle actin stain. Renal blood flow was measured by the non-invasive laser doppler. Results Plasma creatinine (1.94±0.75 vs 1.11±0.44 mg/dL, p=0.005), NGAL (299.7±115.87 vs 140.4±76.56 ng/mL, p=0.004), and KIM-1 (2.09±2.34 vs 0.43±0.89 ng/mL, p=0.024) levels were significantly lower when the 15-PGDH inhibitor was injected before and after iodixanol administration than the vehicle group. But no significant renal protective effect was shown when the 15-PGDH inhibitor was injected before or after iodixanol administration. The 15-PGDH inhibitor administration before and after iodixanol injection showed a significantly wider renal arteriolar area (683.63±248.46 vs 1132.97±357.46 μm2, p=0.039) and larger renal blood flow (360.0±49.72 vs 635.1±27.20, p=0.011) than vehicle administration. Conclusion The 15-PGDH inhibitor has a renal protective effect against CI-AKI in mice by increasing renal blood flow when injected intravenously before and after iodine contrast media administration.