Background: Ischemia-reperfusion injury (IRI) significantly contributes to delayed graft function and inflammation, leading to graft loss. Ischemia-reperfusion injury is exacerbated by the thrombospondin-1-CD47 system through inhibition of nitric oxide signaling. We postulate that CD47 blockade and prevention of nitric oxide inhibition reduce IRI in organ transplantation.
Methods: We used a syngeneic rat renal transplantation model of IRI with bilaterally nephrectomized recipients to evaluate the effect of a CD47 monoclonal antibody (CD47mAb) on IRI. Donor kidneys were flushed with CD47mAb OX101 or an isotype-matched control immunoglobulin and stored at 4°C in University of Wisconsin solution for 6 hr before transplantation.
Results: CD47mAb perfusion of donor kidneys resulted in marked improvement in posttransplant survival, lower levels of serum creatinine, blood urea nitrogen, phosphorus and magnesium, and less histological evidence of injury. In contrast, control groups did not survive more than 5 days, had increased biochemical indicators of renal injury, and exhibited severe pathological injury with tubular atrophy and necrosis. Recipients of CD47mAb-treated kidneys showed decreased levels of plasma biomarkers of renal injury including Cystatin C, Osteopontin, Tissue Inhibitor of Metalloproteinases-1 (TIMP1), β2-Microglobulin, Vascular Endothelial Growth Factor A (VEGF-A), and clusterin compared to the control group. Furthermore, laser Doppler assessment showed higher renal blood flow in the CD47mAb-treated kidneys.
Conclusion: These results provide strong evidence for the use of CD47 antibody–mediated blockade to reduce IRI and improve organ preservation for renal transplantation.
1 Department of Surgery, Washington University School of Medicine, St. Louis, MO.
2 Vasculox, Inc., St. Louis, MO.
3 Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO.
4 Departments of Biochemistry and Molecular Biophysics, Cell Biology, and Physiology, Washington University School of Medicine, St. Louis, MO.
5 Address correspondence to: William C. Chapman, Washington University School of Medicine, 660 S. Euclid Ave., Campus Box 8109, St. Louis, MO 63110.
This study was supported in part by an SBIR Phase I grant award number R43DK092078 from the National Institute of Diabetes and Digestive and Kidney Diseases.
The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Diabetes and Digestive and Kidney Diseases or the National Institutes of Health.
The authors declare no conflicts of interest.
P.M., B.C. and R.H. are employees and shareholders of Vasculox.
Y.L. and P.M contributed equally to this article. Y.L., P.M., W.F., T.M., and W.C. participated in the research design, data analysis, and writing of the article. J.J., J.G., R.H., B.C., Z.X., C.C.C., and G.U. participated in the research design, research performance, and data analysis.
Received 20 November 2013. Revision requested 8 December 2013.
Accepted 14 April 2014.