Macrophages in xenotransplantation

Abstract

Xenotransplantation refers to organ transplantation across species. Immune rejection of xenografts is stronger and faster than that of allografts because of significant molecular differences between species. Recent studies have revealed the involvement of macrophages in xenograft and allograft rejections. Macrophages have been shown to play a critical role in inflammation, coagulation, and phagocytosis in xenograft rejection. This review presents a recent understanding of the role of macrophages in xenograft rejection and possible strategies to control macrophage-mediated xenograft rejection.

Keywords: Coagulation; Inflammation; Macrophages; Xenotransplantation.

Fig. 1

(A-C) Central role of activated macrophages in inflammation, coagulation, phagocytosis, and antigen presentation [31]. TNF, tumor necros; IL, interleukin; MCP-1, monocyte chemoattractant protein 1; DAMP, damage-associated molecular pattern; TLR, Toll-like receptor; TF, tissue factor; PLT, platelet; VWF, von Willebrand factor; PF4, platelet factor 4; TM, thrombomodulin; PAR, protease-activated receptor; ICAM-1, intercellular adhesion molecule-1; VCAM-1, vascular cell adhesion molecule-1; SIRPα, signal regulatory protein α.

Fig. 2

Possible cross-talk between macrophages, hepatocytes, and vascular endothelial cells through the production of interleukin (IL)-6, monocyte chemoattractant protein 1 (MCP-1), and Creactive protein (CRP) in inflammatory responses and coagulation in pig-to-baboon organ transplantation. TF, tissue factor.