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Soluble Urokinase Receptor and Acute Kidney Injury

List of authors.
  • Salim S. Hayek, M.D.,
  • David E. Leaf, M.D.,
  • Ayman Samman Tahhan, M.D.,
  • Mohamad Raad, M.D.,
  • Shreyak Sharma, M.B., B.S.,
  • Sushrut S. Waikar, M.D., M.P.H.,
  • Sanja Sever, Ph.D.,
  • Alex Camacho, Ph.D.,
  • Xuexiang Wang, M.D., Ph.D.,
  • Ranadheer R. Dande, M.D.,
  • Nasrien E. Ibrahim, M.D.,
  • Rebecca M. Baron, M.D.,
  • Mehmet M. Altintas, Ph.D.,
  • Changli Wei, M.D., Ph.D.,
  • David Sheikh-Hamad, M.D.,
  • Jenny S.-C. Pan, M.D.,
  • Michael W. Holliday, Jr., M.D., Ph.D.,
  • James L. Januzzi, M.D.,
  • Steven D. Weisbord, M.D.,
  • Arshed A. Quyyumi, M.D.,
  • and Jochen Reiser, M.D., Ph.D.

Abstract

Background

Acute kidney injury is common, with a major effect on morbidity and health care utilization. Soluble urokinase plasminogen activator receptor (suPAR) is a signaling glycoprotein thought to be involved in the pathogenesis of kidney disease. We investigated whether a high level of suPAR predisposed patients to acute kidney injury in multiple clinical contexts, and we used experimental models to identify mechanisms by which suPAR acts and to assess it as a therapeutic target.

Methods

We measured plasma levels of suPAR preprocedurally in patients who underwent coronary angiography and patients who underwent cardiac surgery and at the time of admission to the intensive care unit in critically ill patients. We assessed the risk of acute kidney injury at 7 days as the primary outcome and acute kidney injury or death at 90 days as a secondary outcome, according to quartile of suPAR level. In experimental studies, we used a monoclonal antibody to urokinase plasminogen activator receptor (uPAR) as a therapeutic strategy to attenuate acute kidney injury in transgenic mice receiving contrast material. We also assessed cellular bioenergetics and generation of reactive oxygen species in human kidney proximal tubular (HK-2) cells that were exposed to recombinant suPAR.

Results

The suPAR level was assessed in 3827 patients who were undergoing coronary angiography, 250 who were undergoing cardiac surgery, and 692 who were critically ill. Acute kidney injury developed in 318 patients (8%) who had undergone coronary angiography. The highest suPAR quartile (vs. the lowest) had an adjusted odds ratio of 2.66 (95% confidence interval [CI], 1.77 to 3.99) for acute kidney injury and 2.29 (95% CI, 1.71 to 3.06) for acute kidney injury or death at 90 days. Findings were similar in the surgical and critically ill cohorts. The suPAR-overexpressing mice that were given contrast material had greater functional and histologic evidence of acute kidney injury than wild-type mice. The suPAR-treated HK-2 cells showed heightened energetic demand and mitochondrial superoxide generation. Pretreatment with a uPAR monoclonal antibody attenuated kidney injury in suPAR-overexpressing mice and normalized bioenergetic changes in HK-2 cells.

Conclusions

High suPAR levels were associated with acute kidney injury in various clinical and experimental contexts. (Funded by the National Institutes of Health and others.)

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Funding and Disclosures

Supported by grants (1R61HL138657-02, 1P30DK111024-03S1, 5R01HL095479-08, 3RF1AG051633-01S2, 5R01AG042127-06, 2P01HL086773-08, U54AG062334-01, 1R01HL141205-01, 5P01HL101398-02, 1P20HL113451-01, 5P01HL086773-09, 1RF1AG051633-01, R01NS064162-01, R01HL89650-01, HL095479-01, 1DP3DK094346-01, and 2P01HL086773, to Dr. Quyyumi; R01HL089650-01 and R01DK101350, to Drs. Sever, Wei, and Reiser; K23DK106448, to Dr. Leaf; and R01HL142093, to Dr. Baron) from the National Institutes of Health, by a grant (15SFCRN23910003, to Dr. Quyyumi) from the American Heart Association, by an American Society of Nephrology Foundation for Kidney Research Carl W. Gottschalk Research Scholar Grant (to Dr. Leaf), by the Hutter Family Professorship (to Dr. Januzzi), by a grant (W81XWH1810667, to Dr. Baron) from the Department of Defense, by a Merit Award (BX002006, to Dr. Sheikh-Hamad) and a Career Development Award (BX002912, to Dr. Pan) from the Department of Veterans Affairs, and by the American Society of Nephrology Foundation for Kidney Research George B. Rathmann Research Fellowship Award, as part of the Ben J. Lipps Research Fellowship Program (to Dr. Holliday).

Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.

Drs. Hayek, Leaf, and Samman Tahhan contributed equally to this article.

We thank the members of the Emory Cardiovascular Biobank team, specifically Yi-An Ko for database maintenance and statistical support, Mosaab Awad and Ayman Alkhoder for serving as coordinators, the staff of the Emory Clinical Cardiovascular Research Institute, and the staff of the Atlanta Clinical and Translational Science Institute for the recruitment of participants, compilation of data, and preparation of samples; Beata Samelko and Jing Li for technical help with mouse tissue and enzyme-linked immunosorbent assay for soluble urokinase plasminogen activator receptor; the members of the Brigham and Women’s Hospital Registry of Critical Illness (Mayra Pinilla, Sam Ash, Paul Dieffenbach, Laura Fredenburgh, and Anthony Massaro); and Myles Wolf (Duke University) and Monnie Wasse (Rush University) for critical reading of an earlier version of the manuscript.

Author Affiliations

From the Division of Cardiology, Department of Medicine, University of Michigan, Ann Arbor (S.S.H.); the Divisions of Renal Medicine (D.E.L., S. Sharma, S.S.W.) and Pulmonary and Critical Care Medicine (R.M.B.), Brigham and Women’s Hospital, the Section of Nephrology, Department of Medicine, Boston University School of Medicine (S.S.W.), and the Divisions of Nephrology (S. Sever) and Cardiology (A.C., N.E.I., J.L.J.), Massachusetts General Hospital — all in Boston; Emory Clinical Cardiovascular Research Institute, Emory University School of Medicine, Atlanta (A.S.T., M.R., A.A.Q.); the Department of Medicine, Rush University Medical Center, Chicago (X.W., R.R.D., M.M.A., C.W., J.R.); the Section of Nephrology, Department of Medicine, Baylor College of Medicine, Houston (D.S.-H., J.S.-C.P., M.W.H.); and the Veterans Affairs Pittsburgh Healthcare System and the University of Pittsburgh School of Medicine, Pittsburgh (S.D.W.).

Address reprint requests to Dr. Hayek at the University of Michigan–Internal Medicine, Frankel Cardiovascular Center, 1500 E. Medical Center Dr., Ann Arbor, MI 48109-1382, or at ; or to Dr. Reiser at Rush University, 1717 W. Congress Pkwy., Chicago, IL 60612, or at .