Repair of bone defects in rhesus monkeys with α1,3-galactosyltransferase-knockout pig cancellous bone

Wenhao Wang; Jiansen Lu; Ying Song; Chun Zeng; Yongkui Wang; Cheng Yang; Bin Huang; Yifan Dai; Jian Yang; Liangxue Lai; Liping Wang; Daozhang Cai; Xiaochun Bai

doi:10.3389/fbioe.2022.990769

Repair of bone defects in rhesus monkeys with α1,3-galactosyltransferase-knockout pig cancellous bone

Front Bioeng Biotechnol. 2022 Sep 12:10:990769. doi: 10.3389/fbioe.2022.990769. eCollection 2022.

Authors

Wenhao Wang¹, Jiansen Lu^{2

3

4}, Ying Song⁵, Chun Zeng², Yongkui Wang², Cheng Yang², Bin Huang², Yifan Dai⁶, Jian Yang⁷, Liangxue Lai⁸, Liping Wang⁹, Daozhang Cai², Xiaochun Bai^{2

10}

Affiliations

¹ Department of Orthopaedics, Shandong Provincial Hospital Affliated to Shandong First Medical University, Jinan, China.
² Academy of Orthopedics, Guangdong Province, Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, China.
³ Department of Joint Surgery, The Fifth Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China.
⁴ Department of Immunology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong, China.
⁵ Department of Endodontics, Jinan Stomatological Hospital, Jinan, China.
⁶ State Key Laboratory of Reproductive Medicine, Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, Jiangsu, China.
⁷ Department of Biomedical Engineering, Materials Research Institute, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, United States.
⁸ Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong, China.
⁹ UniSA Clinical and Health Sciences, University of South Australia, Adelaide, SA, Australia.
¹⁰ Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou, China.

Abstract

Introduction: Since xenografts offer a wide range of incomparable advantages, they can be a better option than allografts but only if the possibility of immunological rejection can be eliminated. In this study, we investigated the ability of α1,3-galactosyltransferase (α1,3-GT) gene knockout (GTKO) pig cancellous bone to promote the repair of a femoral condyle bone defect and its influence on heterologous immune rejection. Materials and methods: Cylindrical bone defects created in a rhesus monkey model were transplanted with GTKO bone, WT bone or left empty. For immunological evaluation, T lymphocyte subsets CD4⁺ and CD8⁺ in peripheral blood were assayed by flow cytometry, and the IL-2 and IFN-γ contents of peripheral blood serum were analyzed by ELISA at 2, 5, 7, 10, and 14 days post-surgery. Micro-CT scans and histological assessment were conducted at 4 and 8 weeks after implantation. Results: Compared with WT-pig bone, the heterologous immunogenicity of GTKO-pig bone was reduced. The defect filled with fresh GTKO-pig bone was tightly integrated with the graft. Histological analysis showed that GTKO-pig cancellous bone showed better osseointegration and an appropriate rate of resorption. Osteoblast phenotype progression in the GTKO group was not affected, which revealed that GTKO-pig bone could not only fill and maintain the bone defect, but also promote new bone formation. Conclusion: GTKO-pig cancellous bone decreased the ratio of CD4⁺ to CD8⁺ T cells and cytokines (IFN-γ and IL-2) to inhibit xenotransplant rejection. Moreover, GTKO group increased more bone formation by micro-CT analysis and osteoblastic markers (Runx2, OSX and OCN). Together, GTKO-pig cancellous bone showed better bone repair than WT-pig cancellous bone.

Keywords: bone transplantation; cylindrical bone defect; gene knockout pig; repair; xenotransplantation.