title: Prolyl-hydroxylase inhibitor activating hypoxia-inducible transcription factors reduce levels of transplant arteriosclerosis in a murine aortic allograft model.
abstract: The development of transplant arteriosclerosis, the hallmark feature of heart transplant rejection, is associated with a chronic immune response and also influenced by an initial injury to the graft through ischaemia and reperfusion. Hypoxia-inducible transcription factor (HIF)-1 pathway signalling has a protective effect against ischaemia-reperfusion injury and has already been demonstrated to ameliorate allograft nephropathy in previous animal studies. Therefore, the aim of this study was to investigate the effect of stabilization of hypoxia-inducible transcription factors with a prolyl-hydroxylase domain (PHD) inhibitor on transplant arteriosclerosis in an experimental aortic allograft model.
  
  
  
  MHC-class I mismatched C.B10-H2(b)/LilMcdJ donor thoracic aortas were heterotopically transplanted into the abdominal aorta of BALB/c mice. Donor animals received a single dose of the PHD inhibitor 2-(1-chloro-4-hydroxyisoquinoline-3-carboxamido) acetate (ICA) (40 mg/kg) or vehicle i.p. 4 h before transplantation. Intragraft HIF accumulation after ICA treatment was detected by immunohistochemistry before and after cold ischaemia (n = 5). Grafts were harvested 30 days after transplantation and analysed by histology (n = 7) and immunofluorescence (n = 7). In addition, intragraft mRNA expression for cytokines, adhesion molecules and growth factors was determined on Day 14 (n = 7).
  
  
  
  Donor preconditioning with ICA resulted in HIF accumulation in the aorta and induction of the HIF target genes vascular endothelial growth factor and transforming growth factor-beta. Vascular lesions were present in both experimental groups. However, there was significantly reduced intimal proliferation in preconditioned grafts when compared with vehicle controls [intimal proliferation 31.3 ± 8% (ICA) vs 55.3 ± 20% (control), P < 0.01]. In addition, experimental groups revealed a down-regulation of E-selectin (-57%) and MCP1 (-33%) expression after ICA pretreatment compared with controls, going along with decreased T-cell [1.4% CD4+ T-cell infiltration vs 8.4% (control) and 4.9% CD8+ T-cell infiltration vs 10.7% (control)], dendritic cell (0.6% dendritic cells infiltration vs 1.9% infiltration(control)] and macrophage infiltration [4.8% macrophages (ICA) vs 10.9% (control)] within vascular grafts.
  
  
  
  These data of an animal transplant model show that the pharmaceutical activation of HIF with endogenous up-regulation of protective target genes leads to adaptation of the graft to low oxygen-saturation and hereby attenuates the development of transplant arteriosclerosis and allograft injury. Pharmaceutical inhibition of PHDs appears to be a very attractive strategy for organ preservation that deserves further clinical evaluation.
authors.affiliation: Department of Cardiac Surgery, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany christian.heim@uk-erlangen.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Heim
authors.affiliation: Department of Nephrology and Hypertension, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Wanja
authors.initials: W
authors.lastname: Bernhardt
authors.affiliation: Department of Cardiac Surgery, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Sabina
authors.initials: S
authors.lastname: Jalilova
authors.affiliation: Department of Nephrology and Hypertension, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Zhendi
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Cardiac Surgery, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Motsch
authors.affiliation: Department of Cardiac Surgery, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Ramsperger-Gleixner
authors.affiliation: Department of Chemistry and Pharmacy, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Nicolai
authors.initials: N
authors.lastname: Burzlaff
authors.affiliation: Department of Cardiac Surgery, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Weyand
authors.affiliation: Department of Nephrology and Hypertension, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Kai-Uwe
authors.initials: KU
authors.lastname: Eckardt
authors.affiliation: Department of Cardiac Surgery, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany Present address: Heart and Diabetes Center NRW, Department of Thoracic and Cardiovascular Surgery, Ruhr-University Bochum, Bochum, Germany.
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Ensminger
mesh_terms: D064591:Allografts; D000818:Animals; D001012:Aorta, Abdominal / Q000637:transplantation*; D001161:Arteriosclerosis / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D051793:Hypoxia-Inducible Factor 1 / Q000235:genetics* / Q000378:metabolism; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D064800:Prolyl-Hydroxylase Inhibitors / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors
chemical_list: D051793:Hypoxia-Inducible Factor 1; D064800:Prolyl-Hydroxylase Inhibitors; D012333:RNA, Messenger; D014157:Transcription Factors
keywords: Hypoxia-inducible transcription factors; Transplant vasculopathy
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