Department of Veterinary Surgery, Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Korea.
Xenotransplantation Research Center, Seoul, Korea.
Xenotransplantation. 2019 Jan;26(1):e12452. doi: 10.1111/xen.12452. Epub 2018 Aug 17.
A long-segmental tracheal lesion is difficult to repair by tracheal allotransplantation due to the lack of a well-defined blood supply for blood vessel anastomosis. The donor trachea needs to be revascularized within a well-vascularized soft tissue flap for several months to allow successful trachea allotransplantation. To date, xenotransplantation using the wild-type or genetically modified pig has been widely studied. The object of this study was to evaluate the feasibility of a small-sized (2 × 2 cm) wild-type pig tracheal patchy in a dog tracheal defect model before trying a long-segment tracheal defect model and using a genetically modified pig as a donor in dog xenotransplantation.
Three healthy beagle dogs (8-9 kg) were used as recipients, and one pig (20 kg) was used as the donor. A pig cartilaginous tracheal patchy (2 × 2 cm half tube) was sutured to the tracheal resected site in each dog. Antithymocyte globulin (2.5 mg/kg infusion, D0 and 1), tacrolimus (4.5 mg/kg, twice a day for 2 months), and methylprednisolone sodium succinate (1 mg/kg, IV, for 2 days and tapering) were administered for immunosuppression. The levels IL-2 and IFN-γ in the serum were measured at D0, 7, and 28. Tracheoscopy was performed at D28, 60, and 90. The recipients were sacrificed at D90, and the expression of dog and pig genes in the graft was evaluated by PCR. Histopathological examination of the graft was conducted.
All of the dogs survived without complications during the experimental period. Their IL-2 and IFN-γ levels were significantly increased at D7 after transplantation compared to D0 and D28 (P < 0.05). The pig tracheal patchy site was open, and no stenosis was observed until D90 on tracheoscopy, when pale mucosa erosion was observed; there was also remnant suture material at D28. However, the tracheal patchy sites gradually became similar to normal mucosa at D60 and 90. The expression of pig genes was detected in the graft by PCR. Normal epithelium and CD3 cells were observed in the histological examination at D90.
In this study, our data suggest that the pig tracheal patchy can be successfully engrafted into the trachea of dog, although erosion of mucosa on the graft was seen at D30, in spite of the discordant species.
由于血管吻合的血供不明确，长节段性气管病变难以通过气管同种异体移植修复。供体气管需要在几个月内通过血管丰富的软组织瓣再血管化，以实现成功的气管同种异体移植。迄今为止，使用野生型或基因修饰猪的异种移植已得到广泛研究。本研究的目的是在尝试长节段气管缺损模型之前，在狗气管缺损模型中评估小型（2×2cm）野生型猪气管补丁的可行性，并在狗异种移植中使用基因修饰猪作为供体。
将 3 只健康比格犬（8-9kg）作为受体，将 1 只猪（20kg）作为供体。将猪软骨气管补丁（2×2cm 半管）缝合到每只狗切除的气管部位。给予抗胸腺细胞球蛋白（2.5mg/kg 输注，D0 和 1）、他克莫司（4.5mg/kg，每天 2 次，持续 2 个月）和甲泼尼龙琥珀酸钠（1mg/kg，IV，连用 2 天，然后逐渐减量）进行免疫抑制。在 D0、7 和 28 时测量血清中 IL-2 和 IFN-γ 的水平。在 D28、60 和 90 时进行气管镜检查。在 D90 处死受者，并通过 PCR 评估移植物中狗和猪基因的表达。对移植物进行组织病理学检查。
所有犬在实验期间均无并发症存活。与 D0 和 D28 相比，移植后第 7 天犬的 IL-2 和 IFN-γ 水平显著升高（P<0.05）。猪气管补丁部位开放，在 D90 气管镜检查时未见狭窄，仅观察到粘膜苍白侵蚀，在 D28 时仍有残留缝线。然而，在 D60 和 90 时，气管补丁部位逐渐变得与正常粘膜相似。通过 PCR 在移植物中检测到猪基因的表达。在 D90 的组织学检查中观察到正常的上皮细胞和 CD3 细胞。
在本研究中，我们的数据表明，尽管存在种间不匹配，猪气管补丁可以成功植入狗的气管，但在 D30 时观察到移植物的粘膜侵蚀。
