Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
Skeletal Biotech Laboratory, Faculty of Dental Medicine, The Hebrew University of Jerusalem, Ein Kerem, Jerusalem, Israel.
Am J Sports Med. 2019 Sep;47(11):2737-2744. doi: 10.1177/0363546519861080. Epub 2019 Jul 23.
Although tendon injuries and repairs are common, treatment of these injuries has limitations. The application of mesenchymal progenitor cells (MPCs) is increasingly used to optimize the biological process of tendon repair healing. However, clinically relevant technologies that effectively assess the localization of exogenous MPCs in vivo are lacking.
Exogenous MPCs labeled with superparamagnetic iron oxide (SPIO) particles would allow monitoring of the localization and retention of cells within the site of implantation via magnetic resonance imaging (MRI) without negatively affecting cell survival or differentiation.
Descriptive laboratory study.
Genetically modified C3H10T1/2 MPCs engineered to express luciferase (Luc+) reporter gene were implanted into surgically created Achilles tendon defects of 10 athymic nude rats (Hsd:RH-Foxn1). Of these animals, 5 animals received Luc+ C3H10T1/2 MPCs colabeled with SPIO nanoparticles (+SPIO). These 2 groups of animals then underwent optical imaging with quantification of bioluminescence and MRI at 7, 14, and 28 days after surgery. Statistical analysis was conducted by use of 2-way analysis of variance. At 28 days after surgery, animals were euthanized and the treated limbs underwent histologic analysis.
Optical imaging demonstrated that the implanted cells not only survived but also proliferated in vivo, and these cells remained viable for at least 4 weeks after implantation. In addition, SPIO labeling did not appear to affect MPC survival or proliferation, as assessed by quantitative bioluminescence imaging ( > .05, n = 5). MRI demonstrated that SPIO labeling was an effective method to monitor cell localization, retention, and viability for at least 4 weeks after implantation. Histologic and immunofluorescence analyses of the repaired tendon defect sites demonstrated tenocyte-like labeled cells, suggesting that cell differentiation was not affected by labeling the cells with the SPIO nanoparticles.
MRI of exogenous MPCs labeled with SPIO particles allows for effective in vivo assessments of cell localization and retention in the setting of tendon regeneration for at least 4 weeks after implantation. This SPIO labeling does not appear to impair cell survival, transgene expression, or differentiation.
SPIO labeling of MPCs appears to be safe for in vivo assessments of MPCs in tendon regeneration therapies and may be used for future clinical investigations of musculoskeletal regenerative medicine.
尽管肌腱损伤和修复是常见的，但这些损伤的治疗存在局限性。间充质祖细胞（MPCs）的应用越来越多地被用于优化肌腱修复愈合的生物学过程。然而，临床上缺乏有效评估外源性 MPC 体内定位的相关技术。
用超顺磁氧化铁（SPIO）颗粒标记的外源性 MPCs 可以通过磁共振成像（MRI）监测细胞在植入部位的定位和保留，而不会对细胞存活或分化产生负面影响。
描述性实验室研究。
将表达荧光素酶（Luc+）报告基因的基因修饰 C3H10T1/2 MPC 植入 10 只去胸腺裸鼠（Hsd：RH-Foxn1）手术造成的跟腱缺损中。其中 5 只动物接受 Luc+C3H10T1/2 MPC 与 SPIO 纳米颗粒共标记（+SPIO）。这两组动物在手术后 7、14 和 28 天分别进行光学成像和 MRI 定量分析。通过使用双因素方差分析进行统计分析。手术后 28 天，处死动物，处理后的肢体进行组织学分析。
光学成像显示，植入的细胞不仅存活下来，而且在体内增殖，这些细胞在植入后至少 4 周仍保持存活。此外，通过定量生物发光成像评估，SPIO 标记似乎不会影响 MPC 的存活或增殖（>.05，n=5）。MRI 显示，SPIO 标记是一种有效的方法，可在植入后至少 4 周内监测细胞的定位、保留和活力。修复的跟腱缺损部位的组织学和免疫荧光分析显示，有腱细胞样标记细胞，表明细胞分化不受 SPIO 纳米颗粒标记的影响。
SPIO 标记的外源性 MPCs 的 MRI 允许在植入后至少 4 周内对肌腱再生过程中的细胞定位和保留进行有效的体内评估。这种 SPIO 标记似乎不会损害细胞存活、转基因表达或分化。
MPCs 的 SPIO 标记似乎可安全用于肌腱再生治疗中外源性 MPCs 的体内评估，并可用于未来对肌肉骨骼再生医学的临床研究。
