Apoptosis and Cellular Activation in the Pathogenesis of Acute Vascular Rejection

• Published in: Circulation research 2002-12, Vol.91 (12), p.1135-1141
• Main Authors: Holzknecht, Zoie E, Kuypers, Karisha L, Plummer, Timothy B, Williams, Josie, Bustos, Matilda, Gores, Gregory J, Brunn, Gregory J, Platt, Jeffrey L
• Format: Article
• Language: English
• Subjects: Acute Disease; Animals; Antibody Formation - immunology; Apoptosis - immunology; Biological and medical sciences; Blood Vessels - immunology; Blood Vessels - pathology; CD59 Antigens - biosynthesis; Disease Models, Animal; Disease Progression; Endothelium, Vascular - immunology; Endothelium, Vascular - metabolism; Endothelium, Vascular - pathology; Fibrin - metabolism; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Gene Expression; Graft Rejection - immunology; Graft Rejection - pathology; Guinea Pigs; Heart Transplantation - adverse effects; Heart Transplantation - immunology; Heart Transplantation - pathology; Humans; In Situ Nick-End Labeling; Medical sciences; Myocardium - immunology; Myocardium - metabolism; Myocardium - pathology; Necrosis; Papio; Rats; Rats, Inbred Lew; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the heart; Swine; Tissue, organ and graft immunology; Transplantation, Heterologous - adverse effects; Transplantation, Heterologous - immunology
• ISSN: 0009-7330; 1524-4571
• DOI: 10.1161/01.RES.0000046236.20251.FA

ABSTRACT—Acute vascular or humoral rejection, a vexing outcome of organ transplantation, has been attributed by some to activation and by others to apoptosis of endothelial cells in the graft. We asked which of these processes causes acute vascular rejection by tracing the processes during the development of acute vascular rejection in porcine cardiac xenografts performed in baboons. Apoptosis, assayed by terminal deoxynucleotidyl transferase–mediated dUTP nick end-labeling (TUNEL), expression of activated caspase-3, and proapoptotic genes Bax and Bcl-xL, was not detected until acute vascular rejection was well advanced, and even then, apoptosis was largely confined to myocytes. Activation of the endothelium, as evidenced by expansion of rough endoplasmic reticulum and increased ribosomal antigen and phospho-p70 S6 kinase, occurred early in the course of acute vascular rejection and progressed through the disease process. These findings suggest that acute vascular rejection is caused by an active metabolic process and not by apoptosis in the endothelium.