Histamine-degrading enzymes as cellular markers of acute small bowel allograft rejection.
Intestinal histamine-degrading enzymes diamine oxidase (DAO) and histamine N-methyltransferase (HNMT) activities are relatively constant per individual and bowel segment, and they reflect the functional integrity of the intestinal mucosa. It was, therefore, hypothesised that a decrease in these enzymes could be indicative of acute rejection of an intestinal allograft. Enzymatic activities of DAO and HNMT were determined in mucosal biopsies of isogeneic (Lewis-to-Lewis, n=48) and allogeneic (Brown Norway-to-Lewis, n=48) heterotopic small bowel transplants in a rat model at various time periods. Allograft recipients were not given any immunosuppression. While no changes in enzyme activities were observed in isografts up to day 8 following transplantation, significantly reduced activities of both enzymes were found in all allografts 6-8 days after transplantation. Activities of both DAO and HNMT exhibited a strong negative correlation with the histological rejection score ( P<0.01). We can conclude that DAO and HNMT activities in gut mucosa are reliable quantitative markers of acute intestinal allograft rejection in the rat that support histopathological analysis.
Klaus
Alexander
A
Department of Surgery, University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria. alexander.klaus@uibk.ac.at
Weiss
Helmut
H
Nguyen
Justin H
JH
Margreiter
Raimund
R
Obrist
Peter
P
Schwelberger
Hubert G
HG
D000208:Acute Disease; D006631:Amine Oxidase (Copper-Containing) / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers; D006084:Graft Rejection / Q000378:metabolism* / Q000473:pathology; D006632:Histamine / Q000378:metabolism*; D006637:Histamine N-Methyltransferase / Q000378:metabolism*; D007421:Intestine, Small / Q000201:enzymology / Q000473:pathology / Q000637:transplantation*; D008297:Male; D051381:Rats; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew; D014184:Transplantation, Homologous
D015415:Biomarkers; D006632:Histamine; D006631:Amine Oxidase (Copper-Containing); D006637:Histamine N-Methyltransferase