P-selectin expression in cold preserved kidneys in University of Wisconsin and histidine-tryptophan-ketoglutarate solutions

Abstract

The differences and efficacy of standard preservation solutions in kidney transplantation, University of Wisconsin (UW) and histidine-tryptophan-ketoglutarate (HTK), remain a topic of debate in recent clinical studies. P-selectins represent glycoproteins expressed on endothelial cells and platelets responsible for the earliest events in ischemia/reperfusion injury in kidney transplantation. This study aimed to compare the levels of P-selectin expression between cold preserved kidney tissues in UW and HTK solutions. Thirty kidneys were procured from male Lewis rats and stored in cold (4°C) solutions for periods of 4, 12, 16, 20, and 24h. Group 1 (n=15) kidneys were stored in UW solutions, and group 2 (n=15) kidneys were submerged in HTK solutions. At the end of each time point, the kidneys underwent preparation and levels of P-selectin expression in the tissues were measured using Immunoblot analyses and adjusted volumetric quantification of Western blot signals. For all periods of cold preservation, P-selectin expression was significantly down-regulated in kidney tissues stored in UW compared with HTK solutions (P<0.001). In summary, UW demonstrated a significant benefit over HTK solution in down-regulating P-selectin expression in cold preserved kidney grafts.

Keywords: P-selectin; University of Wisconsin; histidine-tryptophan-ketoglutarate; kidney transplantation.

FIG. 1

UW solution significantly down-regulated P-selectin expression in cold preserved rat kidneys. (A) Western blot analyses of P-selectin in HTK cold preserved kidneys for 4, 12, 16, 20, and 24 h. (B) Western blot analyses of P-selectin in UW cold preserved kidneys for 4, 12, 16, 20, and 24 h. (C) The adjusted volume of the Western blot signal at each time point was measured using a Moleculare Imager Gel Doc XR system and the data normalized to β-actin internal control. As depicted in the graph, P-selectin was significantly down-regulated in UW as compared with HTK preserved kidneys, for all time periods considered.

FIG. 2

A. Section of normal kidney tissue which has been flushed with cold (4 °C) UW solution during procurement but which has not been preserved for any duration (0 h). The normal tubules and glomeruli serve for comparison with the preserved specimens. (B) Section of normal kidney tissue which has been flushed with cold (4 °C) HTK solution during procurement but which has not been preserved for any duration (0 h). The normal tubules and glomeruli serve for comparison with the preserved specimens. (C) Section of kidney preserved for 12 h in a cold (4 °C) UW solution. Note normal tubules and glomeruli. (D) Section of kidney preserved for 12 h in a cold (4 °C) HTK solution. Intact glomeruli but edematous looking tubules noted. (E). Section of kidney preserved for 24 h in a cold (4 °C) UW solution. Normal glomeruli are noted. Tubules show focal areas of limited disruption of epithelial lining. (F) Section of kidney preserved for 24 h in a cold (4 °C) HTK solution. Global and much more severe disruption of tubular lining cells is noted. The glomeruli, however, remained intact.