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.
Department of Surgery, University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria. alexander.klaus@uibk.ac.at
Alexander
A
Klaus
Helmut
H
Weiss
Justin H
JH
Nguyen
Raimund
R
Margreiter
Peter
P
Obrist
Hubert G
HG
Schwelberger
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