Influence of the new standardized clinical cryopreservation/slow thawing protocol on immunogenicity of arterial allografts in rats

Abstract

Objectives and design At the present time there are two waiting list for patients with vascular prosthetic infection indicated for arterial transplantation in the Czech Republic. The inclusion of each patient for cold-stored or cryopreserved arterial transplantation is the preference of indicating surgeon. In this experimental work we studied the immunogenicity of rat aortal allografts treated by our new clinical cryopreservation/slow thawing protocol. Material and methods Brown-Norway (BN) (N = 6, 203-217 g) or Lewis (LEW) (N = 6, 248-254 g) abdominal aortal grafts treated in accordance with our new clinical cryopreservation/slow thawing protocol were orthotopically transplanted to Lewis recipients (N = 12, 191-245 g). Aortal wall histology and infiltration by recipient immune cells, as well as donor specific anti MHC class I and II antibodies in recipient serum were studied in both isografts and allografts on day 30 postransplant. Core data of cryopreserved allografts were compared to our previous data of cold-stored aortal allografts treated in accordance with our clinical cold-storage protocol. Results Cryopreserved allografts showed regular morphology of aortal wall with clear differentiation of all three basic anatomical layers on day 30 postransplant. Intimal layer showed no hyperplasia, luminal surface was covered by endothelial cells. No statistical difference was observed in tunica media thickness between isografts and allografts. The medial layer

Cell Viability Assessment Using Fluorescence Vital Dyes and Confocal Microscopy in Evaluating Freezing and Thawing Protocols Used in Cryopreservation of Allogeneic Venous Grafts

“…Cryopreservation protocols leading to good post-thaw cell viability are still regarded as the gold standard for the preservation of cardiovascular tissues regardless of the fact that post-transplantation immunosuppressive therapy is necessary to prevent rapid deterioration of the implanted graft [ 16 , 17 , 18 , 19 ]. The presented results showed high immediate post-thaw cell viability in using both thawing protocols ( Table 1 ).…”

“…The current version of the European Union Tissue Establishment Product List [ 30 ] does not include, however, any cardiovascular tissue cryopreserved with cryoprotectants other than DMSO. It is probable that the event of delayed cell death observed in this experimental model may occur after transplantation of the thawed vascular grafts and may cause gentle reduction in the graft cellularity, leading to the lowering of its immunogenicity as observed in experiments with rats [ 18 , 19 ]. For this reason, the possible effect of the different freezing and thawing protocols on the immunogenicity of CVG should be the subject of further research.…”

The Dual Angiogenesis Effects via Nrf2/HO-1 Signaling Pathway of Melatonin Nanocomposite Scaffold on Promoting Diabetic Bone Defect Repair

“…Meanwhile, allografts pose latent risks, including the transmission of diseases and concerns related to immunogenicity. 2 To address these challenges, artificial bone grafts, such as ceramics/polymers or hydrogels, have been widely applied to mimic the biological activity of natural bone. Although research on bone grafts gained rapid progression in recent decades, 1 new bone formation and bone defect repair remain challenging in pathological environments such as tumors, infections, and metabolic diseases.…”