1 3 Int Urol Nephrol DOI 10.1007/s11255-015-0993-1 NEPHROLOGY - ORIGINAL PAPER Expression of bone morphogenetic proteins 4, 6 and 7 is downregulated in kidney allografts with interstitial fibrosis and tubular atrophy Vesna Furic-Cunko 1 · Petar Kes 1 · Marijana Coric 2 · Tvrtko Hudolin 3 · Zeljko Kastelan 3 · Nikolina Basic-Jukic 1 Received: 10 December 2014 / Accepted: 20 April 2015 © Springer Science+Business Media Dordrecht 2015 epithelial cells and does not differ between the compared allografts and control kidney specimens. Conclusion The intensity and expression pattern of BMP4, BMP6 and BMP7 in transplanted kidney tissue are found to be dependent upon the length of the transplanted period, the clinical indication for transplant nephrectomy and signs of IFTA in kidney tissue. Keywords Bone morphogenetic proteins · Chronic graft dysfunction · Interstitial fibrosis tubular atrophy · Kidney · Transplantation · Transplant nephrectomy Introduction Bone morphogenetic proteins (BMPs) are pleiotropic growth factors that regulate growth, differentiation, chemo- taxis and apoptosis of different cell types [1]. They regulate kidney development and maintain structure and function in mature kidneys [2]. In kidney transplant recipients, only one study of biopsy series investigated the role of BMP7 in early fibrogenesis activation after transplantation [3]. The aim of this study is to investigate the connection between the expression pattern of BMPs in kidney allograft tissue versus the cause of allograft dysfunction and the subse- quent need for transplant nephrectomy. Methods Tissue samples Tissue samples from 50 consecutive patients who under- went graft nephrectomy were obtained at the Department of Urology of the University Hospital Zagreb, in Zagreb, Abstract Purpose Bone morphogenetic proteins (BMPs) are pleio- tropic growth factors. This paper investigates the connec- tion between the expression pattern of BMPs in kidney allograft tissue versus the cause of allograft dysfunction. Methods The expression pattern of BMP2, BMP4, BMP6 and BMP7 in 50 kidney allografts obtained by transplant nephrectomy is investigated. Immunohistochemical stain- ing is semiquantitatively evaluated for intensity to identify the expression pattern of BMPs in normal and allograft kid- ney tissues. Results The expression of BMP4 is unique between dif- ferent tubular cell types in grafts without signs of fibrosis. This effect is not found in specimens with high grades of interstitial fibrosis and tubular atrophy (IFTA). In sam- ples with IFTA grades II and III, the BMP7 expression is reduced in a significant fraction of specimens relative to those without signs of IFTA. The expression pattern of BMP6 indicates that its activation may be triggered by the act of transplantation and subsequent reperfusion injury. The expression of BMP2 is strong in all types of tubular * Vesna Furic-Cunko vfcunko@gmail.com 1 Department of Nephrology, Arterial Hypertension, Dialysis and Transplantation, University Hospital Centre Zagreb, Kispaticeva 12, 10 000 Zagreb, Croatia 2 Department of Pathology, University Hospital Centre Zagreb, Kispaticeva 12, 10 000 Zagreb, Croatia 3 Urology Department, University Hospital Centre Zagreb, Kispaticeva 12, 10 000 Zagreb, Croatia