Is Hemopexin a Nephrotoxin or a Marker of Kidney Injury in Renal Ischemia-Reperfusion?

Destabilization of heme proteins is recognized to play a role in acute kidney injury (AKI). Hemopexin (Hpx), known for its role in binding heme, mitigates free heme toxicity. Despite this, the potential adverse effects of Hpx deposition in kidney tissues and its impact on kidney function are not fully understood. Deferoxamine (DFO) chelates iron released from heme and mitigates associated kidney damage. Therefore, this study aimed to evaluate whether Hpx contributes to kidney injury in an ischemia-reperfusion injury (IRI) induced AKI model and to investigate if DFO could alleviate this damage. Mice were categorized into five groups: Sham-Vehicle, Sham-Hpx, IRI-Vehicle, IRI-Hpx, and IRI-Hpx-DFO. Decline in kidney function was observed exclusively in the IRI group, independent of Hpx injection. Serum Hpx levels remained comparable across all groups, and administration of Hpx did not alter serum Hpx levels or kidney function after 24 hours. Although increased Hpx deposition in kidneys was noted in both the IRI and Hpx groups, this accumulation did not correlate with impaired kidney function. Additionally, DFO did not exhibit a protective effect against kidney injury. In summary, Hpx does not directly induce kidney injury and cannot be considered a biomarker for kidney damage caused by IRI.