gms | German Medical Science

122. Kongress der Deutschen Gesellschaft für Chirurgie

Deutsche Gesellschaft für Chirurgie

05. bis 08.04.2005, München

Mitochondrial damage occurs after cold ischemia/reperfusion and progresses with development of chronic rejection in a cardiac allograft model

Meeting Abstract

  • corresponding author S. Schneeberger - Department of General- and Transplant Surgery, D. Swarovski Research Laboratory, Innsbruck Medical University, Innsbruck, Austria
  • A. Amberger - Department of General- and Transplant Surgery, D. Swarovski Research Laboratory, Innsbruck Medical University, Innsbruck, Austria
  • J. Heitzinger - Tyrolean Cancer Research Institute, Innsbruck Medical University, Innsbruck, Austria
  • G. Brandacher - Department of General- and Transplant Surgery, D. Swarovski Research Laboratory, Innsbruck Medical University, Innsbruck, Austria
  • P. Obrist - Department of Pathology, Innsbruck Medical University, Innsbruck, Austria
  • W. Mark - Department of General- and Transplant Surgery, D. Swarovski Research Laboratory, Innsbruck Medical University, Innsbruck, Austria
  • D. Strobl - Department of General- and Transplant Surgery, D. Swarovski Research Laboratory, Innsbruck Medical University, Innsbruck, Austria
  • R. Margreiter - Department of General- and Transplant Surgery, D. Swarovski Research Laboratory, Innsbruck Medical University, Innsbruck, Austria
  • A.V. Kuznetsov - Department of General- and Transplant Surgery, D. Swarovski Research Laboratory, Innsbruck Medical University, Innsbruck, Austria

Deutsche Gesellschaft für Chirurgie. 122. Kongress der Deutschen Gesellschaft für Chirurgie. München, 05.-08.04.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05dgch2923

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/dgch2005/05dgch507.shtml

Published: June 15, 2005

© 2005 Schneeberger et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

Introduction

Prolonged cold organ storage (CI) as a non-immunologic risk factor in the pathogenesis of chronic rejection was evaluated in the Lew to F344 rat cardiac allograft model.

Materials

Hearts were transplanted without cold storage (CR, n = 20) or subjected to 10 h of cold ischemia at 0-1 °C and then transplanted (CRI, n = 28). Both groups were compared with corresponding syngeneic control groups. After evaluation of graft function (score 0-4) hearts were retrieved at 2, 10, 40 and 60 days. Degree of vasculopathy was investigated by means of H&E histology. For investigation of underlaying mechanisms intragraft gene expression was analysed employing cDNA microarray technology („MWG Rat 10k Array", MWG® containing 9715 cDNA sequences) and RT-PCR. A cluster of transcripts regulated in response to cold ischemia as well as chronic rejection were genes encoding for enzymes involved in mitochondrial activity. We therefore ananlysed mitochondrial function using high-resolution respirometry of permeabilised myocardial fibers. In addition, enzymatic defects were assessed in myocardial homogenates.

Results

Cardiac score declined from score 4 at 2 days after reperfusion to score 1.6±0.5 at 60 days. Impairment of organ function was faster in the CRI when compared to the CR group and was nearly absent in isografts. Histology revealed myointimal proliferation and fibrosis after 40 and 60 days in allogeneic groups. Both findings were significantly more pronounced in the CRI group. Microarray analysis allowed for detection of a set of 82 genes regulated at 2 and 10 days in response to cold ischemia in allogeneic groups. In contrast, only 20 genes were regulated in corresponding isografts. 60 Genes were up- or downregulated during chronic rejection and 22 genes were regulated only in chronically rejected grafts undergoing 10h of cold ischemia prior to transplantation. Investigated genes mainly comprised transcripts involved in myocyte function, humoral immune response and enzymes involved in mitochondrial activity. Mitochondrial respiration declined with all substrates used, indicating a more general damage of mitochondria rather than specific defects of respiratory chain complexes. The activity of the mitochondrial matrix enzyme citrate synthase was relatively stable in syngeneic grafts, but decreased substantially (up to 80% at 60 days) in both experimental groups and correlated well with cardiac score. However, enzymatic changes were more evident in CRI group. In contrast, the activity of mitochondrial respiratory chain enzyme complex I equally declined in all groups and did not match with cardiac score. Activity of cytosolic enzyme lactate dehydrogenase was similar in CRI and CR, decreasing to 50 % of syngeneic controls at 60 days.

Discussion

Prolonged CI substantially contributes to the progression of chronic rejection and loss of organ function in this model. Patterns of gene expression as well as mitochondrial respiration and enzymatic injuries reflect severe mitochondrial damage in response to CI and progression of chronic rejection.