Pre-treatment of porcine pulmonary xenograft with desmopressin: A novel strategy to attenuate platelet activation and systemic intravascular coagulation in an ex-vivo model of swine-to-human pulmonary xenotransplantation

Background: Von Willebrand factor (vWF) has been proposed as a major contributor to the development of coagulopathy in pulmonary xenotransplantation. Pretreatment of donor swine with 1-deamino-8-d-arginine vasopressin (DDAVP), an analog of vasopressin, can reduce the content of vWF in pulmonary xenografts. Here, we investigate the effects of DDAVP pre-treatment in an ex-vivo perfusion model of pulmonary xenotransplantation. Methods: We set up and performed the ex-vivo perfusion using porcine pulmonary accessory lobes and fresh human whole blood (n = 12). Half of the donor swine were given 3 μg/kg DDAVP intravenously for 3 days before ex-vivo perfusion (DDAVP group) and half of them were left untreated (control group). The porcine lung was perfused with fresh blood for 1 h and changes in the following parameters were monitored: pulmonary arterial pressure, pulmonary vascular resistance, blood cell counts, fibrinogen, antithrombin, platelet factor 4, D-dimer, C3a, C4d, and xenoreactive IgM. The release of Galα1-3Gal xenoantigen (αGal) from porcine lung which had been perfused and retained for 30 min with human blood was assessed by enzyme-linked immunosorbent assay using αGal-binding lectin. Results: Both DDAVP and control groups showed typical findings of immediate pulmonary dysfunction: an increase of pulmonary vascular resistance and sequestration of leukocytes and platelets after ex-vivo perfusion. However, in the DDAVP group, the increase of platelet factor 4, C3a, and C4d after perfusion was attenuated compared to that in the control group. The release of αGal after blood retention was significantly lower in the DDAVP group than that of the control group. Conclusion: Pre-infusion of DDAVP to the donor swine was beneficial in attenuating platelet activation as well as complement/coagulation activation. These effects of DDAVP are likely to relate to the reduction of porcine vWF content in the xenograft. Therefore, the modulation of vWF secretion in donor lungs could be an additional therapeutic way to reduce systemic coagulopathy in pulmonary xenotransplantation.