EPR oximetry using Ox071 detects acute kidney injury induced by cyclophosphamide

Motivation: EPR oximetry using Ox071 holds promise in detecting chemotherapy-induced acute kidney injury by monitoring pO2 distribution. Goal(s): Using EPR, our study assessed the ability to discern pO2 variations between healthy kidneys and kidney injury models induced by intraperitoneal cyclophosphamide treatment. Approach: To validate these changes, we performed ex vivo histological assessments with pimonidazole staining, comparing these results with EPR based pO2 maps. Results: Analysis of the hypoxic fraction in tumor tissues via pimonidazole staining revealed a transient reduction at 2 days post-treatment, followed by recovery at 30 days. EPR oximetry results consistently mirrored these trends, affirming its reliability as a non-invasive method. Impact: Historically, EPR oximetry focused on tumor hypoxia due to Ox063's limitations in well-oxygenated tissues. Using Ox071, a deuterated analog, current research extends oximetry to normoxic tissues, notably the kidneys.