Elsevier

Transplantation Proceedings

Volume 43, Issue 8, October 2011, Pages 3004-3007
Transplantation Proceedings

Renal transplantation
Complication: Renal
Renalase, A Novel Regulator of Blood Pressure, Is Predicted by Kidney Function in Renal Transplant Recipients

https://doi.org/10.1016/j.transproceed.2011.08.032Get rights and content

Abstract

Background

Renalase is an enzyme that catabolizes catecholamines such as adrenaline and noradrenaline in the circulation. The human kidney releases this protein into the bloodstream to regulate blood pressure. In kidney transplant recipients, the prevalence of hypertension is 60%–80%.

Objective

The aim of our study was to assess possible correlations between renalase, blood pressure, and kidney function among 89 prevalent kidney allograft recipients. To obtain normal ranges, we also studied renalase levels in 27 healthy volunteers.

Methods

Complete blood counts, urea, serum lipids, fasting glucose, and creatinine were measured by standard laboratory methods in the hospital central laboratory. Renalase was assessed with the use of a commercially available kit.

Results

In kidney transplant recipients renalase was significantly higher than in healthy volunteers (P < .001). In kidney transplant recipients, renalase correlated with age (r = 0.29; P < .05), time after transplantation (r = 0.34; P < .01), systolic blood pressure (r = 0.28; P < .05), diastolic blood pressure (r = 0.27; P < .05), serum creatinine (r = 0.49; P < .001), estimated glomerular filtration rate (Chronic Kidney Disease Endemiology collaboration: r = −0.44; P < .0001; Modification of Diet in Renal Disease: r = −0.43; P < .001; Cockcroft-Gault r = −0.39; P < .01), serum phosphate (r = 0.34; P < .05). Upon multiple regression analysis renalase was predicted by 70% using age (beta value 0.21, P = 0.043), time after transplantation (beta value, 0.22; P = .037), serum creatinine (beta value, 0.50; P = .016), and diastolic blood pressure (beta value, 0.33; P = .027).

Conclusions

Renalase is highly elevated in kidney transplant recipients, predominantly dependent on kidney function, which deteriorates with time after kidney transplantation and age. Further studies are needed to establish its putative role in the pathogenesis of hypertension after transplantation and possible novel targeted therapies.

Section snippets

Materials and Methods

These studies were performed on 80 kidney allograft recipients (58 males). Before transplantation, all of the recipients were on renal replacement therapy. The immunosuppressive regimen of kidney transplant recipients consisted of a calcineurin inhibitor in combination with mycophenolate mofetil, a mammalian target of rapamycin inhibitor, or prednisone. All subjects maintained sufficient stable graft function, showing no clinical signs of rejection or inflammation. Each subject gave informed

Results

Clinical and biochemical data of kidney allograft recipients are shown in Table 1. The mean serum renalase among recipients was significantly higher compared with the control group (6.72 ± 4.50 µg/mL vs 3.86 ± 0.73 µg/mL; P < .001). In kidney transplant recipients renalase correlated with age (r = 0.29; P < .05), time after transplantation (r = 0.34; P < .01) and systolic blood pressure (r = 0.28; P < .05; Fig 1) as well as diastolic blood pressure (r = 0.27; P < .05), serum creatinine (r =

Discussion

We observed that renalase was significantly higher among kidney transplant recipients compared with healthy volunteers. In addition, renalase content was related to kidney function, age, time after transplantation, serum phosphate, and blood pressure. On multiple regression analysis, renalase level was predicted independently by age, kidney function, time after transplantation, and diastolic blood pressure.

The connection between renalase and hypertension was demonstrated by Zhao et al12 in the

References (15)

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