Assessing Mouse Kidney Parvovirus’ Ability to Confound Research by Examining its Effects on Renally Excreted Chemotherapeutics and its Impact on Pathologic Endpoints in the Adenine Model of Chronic Kidney Disease

Mouse kidney parvovirus (MKPV) causes inclusion body nephropathy in severely immunocompromised mice and renal interstitial inflammation in immunocompetent mice. The purpose of this 2-part study was to determine the impact that MKPV may have on preclinical models as it relates to the pharmacokinetics of chemotherapeutics as well as its impact on the adenine diet model of chronic kidney disease. To assess the impact of MKPV on pharmacokinetics of 2 renally excreted chemotherapeutics commonly used in preclinical oncology studies, methotrexate and lenalidomide, blood and urine drug concentrations were measured in MKPV-infected or uninfected immunodeficient NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) and immunocompetent C57BL/6NCrl (B6) female mice. Differences in plasma pharmacokinetics were observed for methotrexate, but not for lenalidomide. Differences were most profound between uninfected NSG and B6 mice. The area under the curve (AUC) of methotrexate was 1.5-fold higher in uninfected NSG mice compared to infected NSG mice, 1.9-fold higher in infected B6 mice compared to uninfected B6 mice, and 4.3-fold higher in uninfected NSG mice compared to uninfected B6 mice. Renal clearance of both drugs was not impacted by MKPV infection but was generally lower in NSG mice. To assess the impact of MKPV on the adenine diet model of chronic kidney disease, MKPV-infected and uninfected B6 female mice were fed a 0.2% adenine diet and clinical and histopathologic features of disease were assessed over 8 weeks. Infection with MKPV did not have a significant impact on serum biomarkers of renal function such as BUN, creatinine, and SDMA; urine chemistry; or hemogram. However, infection did impact select histologic outcomes. MKPV-infected mice had significantly more foci of interstitial lymphoplasmacytic infiltrates than uninfected mice after 4 and 8 weeks of diet consumption, and significantly less interstitial fibrosis at week 8. Macrophage infiltrates and renal tubular injury, assessed using various immunohistochemical stains, were similar between groups. Together, these findings indicate that MKPV infection had minimal impact on the renal excretion of 2 chemotherapeutics and serum biomarkers of renal function. However, infection significantly impacted select histologic features of renal disease in the adenine diet model. While MKPV-free mice should be used in biomedical research, it is of the utmost importance in studies evaluating renal histology as an experimental outcome.