Endothelin-1 immunoreactivity and mRNA in the transplanted human heart.
Endothelin-1 (ET-1) is a 21-residue peptide produced by endothelial cells and possesses a wide range of biological activities, including vasoconstriction, mitogenesis, and inotropic effects on the heart. The aim of the present study was to determine the cellular localization of ET-1 immunoreactivity and mRNA in routine endomyocardial biopsy specimens of transplanted human hearts, and to correlate the findings with the associated histological changes. Multiple-step paraffin sections of 72 biopsy samples were immunostained with antiserum to ET-1 and von Willebrand factor (factor VIII) using the avidin-biotin-peroxidase complex method. ET-1 immunoreactivity was localized to vascular and endocardial endothelial cells, as well as to cardiomyocytes. The pattern of endothelial cell immunostaining with the ET-1 antiserum was similar to that of factor VIII. Previous biopsy sites and areas of granulation tissue appeared to have greater ET-1 immunoreactivity, particularly in sections immunostained with the ET-1 antiserum. There was a significant correlation between the presence of ET-1 immunoreactivity and fibrosis or granulation tissue in the biopsy specimens (P < 0.03). There was no correlation between ET-1 immunoreactivity and the presence of cellular infiltrate, definitive rejection, or Quilty effect. In situ hybridization with radiolabeled RNA probes revealed expression of ET-1 mRNA in endothelial cells and myocytes, also in association with granulation tissue and fibrosis. No cellular reactivity was present in control sections stained with the ET-1 antiserum preadsorped with its synthetic peptide. The findings suggests a possible role for ET-1 in vascular regeneration and angiogenesis following myocardial injury.
Giaid
A
A
Department of Pathology, Montreal General Hospital, McGill University, Québec, Canada.
Saleh
D
D
Yanagisawa
M
M
Forbes
R D
RD
D001706:Biopsy; D004699:Endocardium / Q000378:metabolism; D016232:Endothelins / Q000032:analysis*; D016027:Heart Transplantation; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D009206:Myocardium / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis
D016232:Endothelins; D012333:RNA, Messenger