Date: Sunday, June 2, 2019
Session Time: 6:00pm-7:00pm
Presentation Time: 6:00pm-7:00pm
Location: Hall C & D
*Purpose: Vascularized composite allotransplantation (VCA) is a viable reconstructive option for devastating tissue defects. The growth of the field is restrained by the limited ischemia time that is tolerated by the graft. Long-term graft preservation would allow for better donor matching and provide additional time to pre-condition recipients for novel immunomodulatory regimens. We present first outcomes for cryopreservation in a rat hind limb model.
*Methods: Lewis rats served as donors (7) and recipients (14) of orthotopic hind limb transplants. Limbs were flushed with heparinized Lactated Ringers, loaded with 10% DMSO in Culture Medium, cooled at 1oC/min to -90oC and stored below -130oC for 1-2 weeks. Non-frozen controls (N=2) were performed. Intervention groups: controlled cooling rate frozen limbs with A) Spontaneous nucleation (N=8), B) Induced nucleation at -4oC (N=4). Thawed and tissue DMSO concentration reduced limbs were transplanted at the mid-thigh. Recipients were monitored daily until the study endpoints of Post-Operatieve Day (POD) 14 and 30. Biopsies were acquired at POD7 and endpoint. H&E stained samples were histologically reviewed. Pre-implanted limbs were evaluated for tissue viability using a metabolic resazurin assay.
*Results: Post-rewarming femoral arteries, skin and cartilage were >70% of fresh control viability; muscle was 35-40% (p<0.05). All control limb transplants were viable at POD14. All transplanted limbs established blood flow. 1 of 8 spontaneous nucleation limbs was viable at POD7. Histopathology revealed regeneration of skeletal myofibers and associated fibrosis at POD10. 2 of 4 induced nucleation limbs (50%) demonstrated gross signs of healing around the ankles and feet by POD7 and further skin and muscle regeneration between POD7-30.
*Conclusions: We report the first above-knee cryopreserved rat limb graft survival after frozen storage. Further improvement in muscle viability is needed. Between POD7-30 limbs grossly improved demonstrating that the cryopreserved tissues had regenerative capacity. These studies constitute critical first steps toward VCA banking.
To cite this abstract in AMA style:Fidder SA, Oh B, Messner F, Furtmueller G, Helke K, Greene E, Chen Z, Campbell L, Brandacher G, Brockbank K. Cryopreservation Allows for Extended Graft Survival in a Rat Orthotopic Hind Limb Model [abstract]. Am J Transplant. 2019; 19 (suppl 3). https://atcmeetingabstracts.com/abstract/cryopreservation-allows-for-extended-graft-survival-in-a-rat-orthotopic-hind-limb-model/. Accessed February 27, 2021.
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