Urine podoplanin heralds the onset of ischemia-reperfusion injury of the kidney.

Ischemia-reperfusion injury represents one of the most common causes of acute kidney injury, a serious and often deadly condition that affects up to 20% of all hospitalized patients in the United States. However, the current standard assay used universally for the diagnosis of acute kidney injury, serum creatinine, does not detect renal damage early in its course. Serendipitously, we found that the immunofluorescent signal of the constitutive podocyte marker podoplanin fades in the glomerulus and intensifies in the tubulointerstitial compartment of the kidney shortly after ischemia-reperfusion injury in 8- to 10-wk-old male C57Bl/6j mice. Therefore, we sought to define the appearance and course of the podoplanin-positive signal in the kidney after ischemia-reperfusion injury. The tubulointerstitial podoplanin-positive signal increased as early as 2 h but persisted for 7 days after ischemia-reperfusion injury. In addition, the strength of this tubulointerstitial signal was directly proportional to the severity of ischemia, and its location shifted from the tubules to interstitial cells over time. Finally, we detected podoplanin in the urine of mice after ischemia, and we observed that an increase in the urine podoplanin-to-creatinine ratio correlated strongly with the onset of renal ischemia-reperfusion injury. Our findings indicate that the measurement of urine podoplanin harbors promising potential for use as a novel biomarker for the early detection of ischemia-reperfusion injury of the kidney.

Impact of Thrombotic Microangiopathy on Renal Outcomes and Survival after Hematopoietic Stem Cell Transplantation.

Transplantation-associated thrombotic microangiopathy (TA-TMA) is a serious complication of hematopoietic stem cell transplantation (HSCT). We characterized the incidence, risk factors, and long-term outcomes associated with TA-TMA by performing a comprehensive review of all adult patients (n = 1990) undergoing allogeneic HSCT at the Dana Farber Cancer Institute/Brigham and Women's Hospital between 2005 and 2013. Using the City of Hope criteria, we identified 258 patients (13%) with "definite" TMA and 508 patients (26%) with "probable" TMA. Mismatched donor transplantation (subdistribution hazard ratio [sHR], 1.79; 95% confidence interval [CI], 1.17 to 2.75; P = .007), sirolimus-containing graft-versus-host disease prophylaxis (sHR, 1.73; 95% CI, 1.29 to 2.34; P < .001), myeloablative conditioning (sHR, 1.93, 95% CI, 1.38 to 2.68; P < .001), and high baseline lactate dehydrogenase (LDH) level (sHR, 1.64; 95% CI, 1.26 to 2.13; P < .001) were associated with definite TMA. Moreover, positive cytomegalovirus serostatus (sHR, 1.41; 95% CI, 1.16 to 1.71; P < .001), high and very high disease risk index (sHR, 1.48; 95% CI, 1.12 to 1.96, P = .007), and high baseline LDH level (sHR, 1.25; 95% CI, 1.05 to 1.49; P = .011) were associated with probable TMA. In multivariable analyses, definite and probable TMA were each independently associated with higher mortality (HR, 5.24; 95% CI, 4.43 to 6.20 and HR, 2.12; 95% CI, 1.84 to 2.44, respectively), and long-term kidney dysfunction (HR, 5.43; 95% CI, 4.61 to 6.40 and HR, 2.20; 95% CI, 1.92 to 2.51, respectively). Definite and probable TMA were also independently associated with an increased risk of nonrelapse mortality and shorter progression-free survival. Our findings indicate that TA-TMA is common following HSCT and is independently associated with increased risk of death and kidney dysfunction.