Abstract 95: S-nitrosylation Therapy To Improve Ex-vivo Parameters Of Vascular Composite (vca): Study On Brain Dead Porcine

Abstract

S-Nitrosylation Improves ex-vivo parameters of vascular composite (VCA): Study on brain dead swine Background: Brain death (BD) results in disruption of S-Nitrosohemoglobin (SNO-Hb) leading to decrease tissue micro perfusion. In a pre-clinical study on bd swine, we found that repletion of SNO-Hb by S-nitrosylation agent as ethyl nitrite (ENO) improves organ function. Vascularized composite allograft (VCA) is a viable therapeutic option for correction of composite tissue loss as limb amputation, abdominal trauma and severe facial damage. Although significant progress has been made with VCA surgical techniques and anti-rejection drug regimens, less attention has been directed to care of the tissue composite preservation. It is the physiologic status of the donor that often drives tissue availability and short-term VCA outcome. We hypothesized that additional of ENO during composite storage could restore composite microcirculation and thus improves outcome. Methods: VCA (n=8) and hind limb (n=6) were harvested from induced bd swine. Each composite was placed on a Lifeport storage machine and cold pulsatile perfusion was started at a targeted pressure 22 ± 5 mmHg for VCA and 13±2 for limb. Flow and resistance measurements were recorded during the experiment. ENO was aerated to the preservative solution for 2 hours (50ppm) for the treated composites. Data points were extracted from machine-generated values. Rate of change (slope) in flow rate and resistance were calculated. We compared values from control group to ENO treated group using Wilcoxon rank sum tests. GraphPad Prism software was used and considered a p < 0.05 to be statistically significant. Results: Flow and resistance measurements were expressed as percent change from baseline. For the duration of the pumping period. VCA flow rate in the ENO-treated group (n=2) was significantly higher (p<0.0001; 95% CI -17.22 to -9.743) than the control group (n=6), As well as, resistance was significantly decreased in ENO-treated group (p=0.0004; 95% CI 11.86 to 33.96). Similarly, limbs flow rate in the ENO-treated group (n=3) was significantly higher (p<0.0001; 95% CI -11.52 to -2.36) than control limb (n=3) as well as resistance significantly decreased in ENO-treated group (p<0.0001; 95% CI 11.51 to 24.13). Conclusions: S-nitrosylation therapy (ENO) during ex vivo storage of VCA holds promise to increase the number and quality of VCA available for transplant.