Increased Th17 rather than Th1 alloimmune response is associated with cardiac allograft vasculopathy after hypothermic preservation in the rat.
BACKGROUND
Preservation injury decreases patient survival and promotes the development of cardiac allograft vasculopathy. We investigated the sequential effects of hypothermic preservation on ischemia-reperfusion injury (IRI), subsequent innate immune activation, and adaptive immune response in rat cardiac allografts.


METHODS
Allografts were transplanted from fully major histocompatibility complex-mismatched Dark Agouti to Wistar Furth rats without pre-operative hypothermia or after 4 hours of hypothermic preservation. Recipients received cyclosporine A immunosuppression. The allografts were recovered at 6 hours (n = 6, 7), 24 hours (n = 6), 10 days (n = 5), and 8 weeks (n = 5). Immunohistochemical, histologic, and reverse-transcription polymerase chain reaction analysis was performed.


RESULTS
In IRI, significantly increased messenger RNA (mRNA) levels for Toll-like receptor 4, hyaluronan synthases (HAS)1-2 (p = 0.03), high-mobility group box 1 (p = 0.05), CD80/83 (p = 0.01, p = 0.048), and the cytokines tumor necrosis factor-alpha (p = 0.004), interferon-gamma (p = 0.012), and interleukin (IL)-6 (p = 0.019) were seen in allografts subjected to hypothermic preservation. During established alloimmune response, allografts subjected to hypothermic preservation expressed prominent infiltration of CD4+ T cells (p = 0.043) and dendritic cells (p = 0.029) and significantly up-regulated mRNA levels of CD80 (p = 0.036), chemokine (C-C motif) ligand 21 (p = 0.008), C-C chemokine receptor type 7 (p = 0.003), vascular endothelial growth factor-C (p = 0.016), and vascular endothelial growth factor receptor-3 (p = 0.02). These allografts also showed prominent mRNA upregulation of Foxp3 (p = 0.014), IL-17 (p = 0.038), and IL-23 (p = 0.043). Preservation significantly increased the incidence and intensity of allograft arteriosclerosis (p < 0.05) and cardiac fibrosis (p = 0.003) at 8 weeks.


CONCLUSIONS
Our results demonstrate that preservation injury induced a cascade leading to an innate immune response that modulated the adaptive immune response towards Th17 rather than Th1 T-cell response in rat cardiac allografts and ultimately enhanced cardiac fibrosis and arterial occlusion. Our results also suggest that this immune response was not regulated by the calcineurin inhibitor cyclosporine A.
Syrjälä
Simo O
SO
Cardiopulmonary Research Group, Transplantation Laboratory, Haartman Institute, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland. simo.syrjala@helsinki.fi
Keränen
Mikko A I
MA
Tuuminen
Raimo
R
Nykänen
Antti I
AI
Tammi
Markku
M
Krebs
Rainer
R
Lemström
Karl B
KB
D000208:Acute Disease; D000818:Animals; D015703:Antigens, CD / Q000235:genetics; D002908:Chronic Disease; D016572:Cyclosporine / Q000627:therapeutic use; D003713:Dendritic Cells / Q000276:immunology; D006084:Graft Rejection / Q000453:epidemiology / Q000276:immunology; D016027:Heart Transplantation / Q000276:immunology* / Q000473:pathology; D007136:Immunoglobulins / Q000235:genetics; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008562:Membrane Glycoproteins / Q000235:genetics; D009926:Organ Preservation / Q000379:methods; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011919:Rats, Inbred Strains; D011920:Rats, Inbred WF; D015424:Reperfusion / Q000379:methods; D018417:Th1 Cells / Q000276:immunology*; D058504:Th17 Cells / Q000276:immunology*; D013997:Time Factors; D014184:Transplantation, Homologous / Q000276:immunology; D000097802:CD83 Antigen
D015703:Antigens, CD; D016572:Cyclosporine; D007136:Immunoglobulins; D007166:Immunosuppressive Agents; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D000097802:CD83 Antigen