College of Medicine, Nursing and Health Sciences, Biomedical Sciences, Regenerative Medicine Institute, National University of Ireland Galway, Galway, Ireland.
Discipline of Pharmacology and Therapeutics, College of Medicine, Nursing and Health Sciences, National University of Ireland Galway, Galway, Ireland.
Stem Cell Res Ther. 2021 Apr 6;12(1):227. doi: 10.1186/s13287-021-02293-x.
Systemic administration of mesenchymal stromal cells (MSCs) has been efficacious in many inflammatory disease settings; however, little data are available on the potential immunomodulatory effects following local MSC administration in the context of corneal transplantation. The purpose of this study was to assess the potential of subconjunctival injection of MSCs to promote corneal allograft survival.
MSCs were isolated from female C57BL/6 (H-2) or Balb/c (H-2) mice and extensively characterized. An allogeneic mouse corneal transplant model was used with Balb/c mice as recipients of C57BL/6 grafts. A dose-finding study starting with 5 × 10 MSCs injected subconjunctivally at day - 7 was tested first followed by a more clinically translatable low-dose single or dual injection strategy on day - 1 and day + 1 before/after transplantation. Graft transparency served as the primary indicator of transplant rejection while neovascularization was also recorded. Lymphocytes (from draining lymph nodes) and splenocytes were isolated from treatment groups on day 2 post-transplantation and characterized by flow cytometry and qRT-PCR.
Both high- and low-dose injection of allogeneic MSCs on day - 7 led to 100% graft survival over the observation period. Moreover, low-dose dual subconjunctival injection of 5 × 10 allogeneic MSCs on day - 1 or day + 1 led to 100% allograft survival in transplant recipients (n = 7). We also demonstrate that single administration of allogeneic MSCs on either day - 1 or day + 1 promotes rejection-free graft survival in 100% (n = 8) and 86% (n = 7) of transplanted mice, respectively. Early time point ex vivo analysis suggests modulation of innate immune responses towards anti-inflammatory, pro-repair responses by local MSC administration.
This work demonstrates that low-dose subconjunctival injection of allogeneic MSCs successfully promotes corneal allograft survival and may contribute to refining future MSC immunotherapies for prevention of corneal allograft rejection.
间充质基质细胞（MSCs）的全身给药在许多炎症性疾病治疗中已显示出疗效；然而，关于角膜移植背景下局部 MSC 给药后的潜在免疫调节作用的数据很少。本研究的目的是评估结膜下注射 MSC 促进角膜同种异体移植物存活的潜力。
从雌性 C57BL/6（H-2）或 Balb/c（H-2）小鼠中分离 MSC，并进行广泛的表征。使用 Balb/c 小鼠作为 C57BL/6 移植物的受者，建立同种异体小鼠角膜移植模型。首先进行了剂量发现研究，即从第-7 天开始结膜下注射 5×10 MSC，然后在移植前/后第-1 天和第+1 天进行更具临床转化意义的低剂量单次或双重注射策略。移植物透明度作为排斥反应的主要指标，同时还记录了新生血管形成。在移植后第 2 天，从治疗组中分离引流淋巴结和脾淋巴细胞，并通过流式细胞术和 qRT-PCR 进行表征。
第-7 天注射高剂量和低剂量同种异体 MSC 均导致观察期内 100%的移植物存活。此外，在移植受者中，第-1 天或第+1 天低剂量双重结膜下注射 5×10 同种异体 MSC 导致 100%的同种异体移植物存活（n=7）。我们还证明，在第-1 天或第+1 天单次给予同种异体 MSC 均可使 100%（n=8）和 86%（n=7）的移植小鼠实现无排斥反应的移植物存活。早期的离体分析表明，局部 MSC 给药可调节固有免疫反应，使其向抗炎、促进修复的反应方向发展。
这项工作表明，低剂量结膜下注射同种异体 MSC 可成功促进角膜同种异体移植物存活，并可能有助于完善未来用于预防角膜同种异体移植物排斥反应的 MSC 免疫疗法。
