Background: Microvascular dysfunction (MVD) in cardiac allografts is associated with death, graft failure, or allograft vasculopathy after heart transplantation. Ischemia/reperfusion injury and proinflammatory mediators promote MVD. Proinflammatory mediators are elevated in the blood of organ donors. Machine perfusion (MP) of donor hearts with blood that has been collected from the organ donor is a novel preservation method. Therefore, we investigated the effect of a cytokine adsorber during blood perfusion of hearts to reduce MVD and preserve the microvascular endothelium.
Method: In a pig model, hearts were harvested and maintained for 4 hours by MP with blood with (w CytoA, N = 5) or without (w/o CytoA, N = 5) an integrated cytokine adsorber. Microvascular blood flow (LDP) was measured for 60 minutes by Laser-Doppler-Perfusion Technology with a balloon-induced left ventricular preload. In a third group (Control, N = 5), LDP was measured immediately after harvesting. We performed immunohistochemical staining of cell adhesion molecules ICAM, VCAM, PECAM, and eNOS. Additionally, we profiled the gene expression from left ventricular tissue samples. We analyzed the correlative relation of expressed genes after preselection by machine learning using the Boruta method.
Results: Relative LDP (rLDP) was significantly improved in the wCytoA-group (1.27 ± 0.07 vs. 0.78 ± 0.04; p < 0.001) compared with w/o CytoA. The expression of endothelial viability marker eNOS majorly increased, and the expression of endothelial injury markers ICAM, VCAM, and PECAM majorly decreased in the wCytoA group, compared with w/o CytoA. The control group showed a centralized gene cluster. We found a fragmented gene network with heterogeneous gene correlation in the w/o CytoA-group. Use of a cytokine adsorber reconstituted major cluster regions of correlation. Three genes were discovered to allow clear differentiation between groups: HIF1A, CAV1, and FDF2.
Conclusion: Use of a cytokine adsorption device during MP of donor hearts with blood counteracts preload-dependent MVD, protects the microvascular endothelium by downregulation of adhesion molecules, and partially reconstitutes regulation and correlation of genes.
