Bone vascularized composite allotransplantation model in swine tibial defect: Evaluation of surgical angiogenesis and transplant viability. Issue 2 (5th March 2018)

• Record Type: Journal Article
• Authors: Kotsougiani, Dimitra; Hundepool, Caroline A.; Bulstra, Liselotte F.; Friedrich, Patricia F.; Shin, Alexander Y.; Bishop, Allen T.
• Is Part Of: Microsurgery. Volume 39:Issue 2(2019)
• Page Start: 160
• Page End: 166
• Publication Date: 2018-03-05
• Subjects: Microsurgery -- Periodicals; 617.05
• DOI: 10.1002/micr.30310
• Languages: English
• ISSNs: 0738-1085

Abstract

Abstract : Introduction: In prior small animal studies, we maintained vascularized bone allotransplant viability without long‐term immunotherapy. Instead, an autogenous neoangiogenic circulation is created from implanted vessels, sufficient to maintain bone viability with only 2 weeks immunosupression. Blood flow is maintained despite rejection of the allogeneic vascular pedicle thereafter. We have previously described a large animal (swine) pre‐clinical model, reconstructing tibial defects with vascularized tibial allotransplants. In this manuscript, autologous angiogenesis is evaluated in this model and correlated with bone viability. Materials and methods: Allogeneic tibial segments were transplanted across a major swine leukocyte antigen mismatch. Microvascular repair of the bone VCA pedicle was combined with intraosseous implantation of an autogenous arteriovenous (AV) bundle. The bundle was ligated in group 1 ( n = 4), and allowed to perfuse in group 2 ( n = 4). Three‐drug immunotherapy was given for 2 weeks. At 16 weeks micro‐CT angiography quantified neoangiogenic vessel volume. Bone viability, rejection grade, and bone healing were analyzed. Results: A substantial neoangiogenic circulation developed from the implanted AV‐bundle in group 2, with vessel density superior to ligated AV‐bundle controls (0.11 ± 0.05 vs. 0.01 ± 0.01, P = .029). Bone allotransplant viability was also significantly enhanced by neoangiogenesis (78.7 ± 4.4% vs. 27.7 ± 5.8%, P = .028) with higher bone healing scores (21.4 ± 2.9 vs. 12.5 ± 3.7, P = .029). Ligated control tibias demonstrated disorganized bone morphology and higher local inflammation ( P = .143). Conclusion: Implantation of autogenous AV bundles into vascularized bone allotransplants resulted in the rapid formation of a neoangiogenic autogenous blood supply in a swine tibia model that maintained bone viability, improved bone healing, and minimized rejection.