Pregnancy-associated plasma protein a and soluble receptor for advanced glycation end products after kidney transplantation

Abstract

Background: Pregnancy-associated plasma protein A (PAPP-A) and soluble receptor for advanced glycation end products (sRAGE) are new markers related to vascular damage.

Methods: Thirty-one patients who had undergone kidney transplantation (TX) in the year 2005 under tacrolimus-based immunosuppression were included in this prospective single-center study. PAPP-A and sRAGE were determined before TX and 2 and 6 weeks and 3 months after TX. The results were correlated with the 3-month protocol kidney graft biopsy findings.

Results: Both PAPP-A and sRAGE decreased after TX (mean values in serum: PAPP-A 20.8, 13.7, 12.1, and 10.7 mIU/l, respectively, before and 2 and 6 weeks and 3 months after TX, p < 0.001; sRAGE 4,403.4, 2,512.7, 1,909.0, and 1,817.6 pg/ml, respectively, before and 2 and 6 weeks and 3 months after TX, p < 0.001) and were correlated with the graft function (PAPP-A vs. modification of diet in renal disease formula r = -0.52, p < 0.001; sRAGE vs. modification of diet in renal disease formula r = -0.54, p < 0.001). Additionally, the PAPP-A levels correlated with interstitial inflammation (r = 0.57, p < 0.05) and vascular intimal thickening (r = 0.47, p < 0.05), while sRAGE correlated with arteriolar hyalinosis (r = 0.49, p < 0.05).

Conclusions: Our study demonstrates the role of the kidney in the metabolism and/or the removal of PAPP-A and sRAGE. After successful TX, these substances decrease, and, on the contrary, early chronic vascular changes in the kidney TX are associated with elevation of their serum levels.