Neuroregeneration Laboratory, Department of Anesthesiology, University of California-San Diego, La Jolla, CA 92093-0695, USA.
Cell Transplant. 2011;20(8):1153-61. doi: 10.3727/096368910X564553. Epub 2011 Jun 9.
Previous rodent studies employing monotherapy or combined immunosuppressive regimens have demonstrated a variable degree of spinal xenograft survival in several spinal neurodegenerative models including spinal ischemia, trauma, or amyotrophic lateral sclerosis (ALS). Accordingly, the characterization of optimal immunosuppressive protocols for the specific neurodegenerative model is critical to ensure reliable assessment of potential long-term therapeutic effects associated with cell replacement. In the present study we characterized the survival of human spinal stem cells when grafted into the lumbar spinal cords of a rodent model of ALS, SOD1 (G93A) male and female rats (60-67 days old). Four different immunosuppressive protocols were studied: i) FK506 (q12h); ii) FK506 (qd) + mycophenolate (PO; q12h, up to 7 days postop); iii) FK506 (qd) + mycophenolate (IP; q12h, up to 7 days postop); and iv) FK506 (qd) + mycophenolate (IP; qd, up to 7 days postop). Three weeks after cell grafting the number of surviving human cells was then systematically assessed. The highest density of grafted cells was seen in animals treated with FK506 (qd) and mycophenolate (IP; qd; an average 915 ± 95 grafted cells per spinal cord section). The majority of hNUMA-positive cells colocalized with doublecortin (DCX) immunoreactivity. DCX-positive neurons showed extensive axodendritic sprouting toward surrounding host neurons. In addition, migrating grafted cells were identified up to 500 μm from the graft. In animals treated with FK506 (q12h), FK506 (qd) + mycophenolate (PO; q12h) or FK506 (qd) + mycophenolate (IP; q12h), 11.8 ± 3.4%, 61.2 ± 7.8%, and 99.4 ± 8.9% [expressed as percent of the FK506 (qd) and mycophenolate (IP; qd)] cell survival was seen, respectively. In contrast to animals treated with a combination of FK506 + mycophenolate, robust CD4/8 immunoreactivity was identified in the vicinity of the injection tract in animals treated with FK506 only. These data suggest that a combined, systemically delivered immunosuppression regimen including FK506 and mycophenolate can significantly improve survival of human spinal stem cells after intraspinal transplantation in SOD1 (G93A) rats.
先前的啮齿动物研究采用单药或联合免疫抑制方案，在包括脊髓缺血、创伤或肌萎缩侧索硬化症（ALS）在内的几种脊髓神经退行性模型中，证明了脊髓异种移植物的存活程度存在差异。因此，对于特定的神经退行性模型，确定最佳免疫抑制方案对于确保可靠评估与细胞替代相关的潜在长期治疗效果至关重要。在本研究中，我们研究了人类脊髓干细胞在 ALS 模型 SOD1（G93A）雄性和雌性大鼠（60-67 天大）的脊髓中的存活情况。研究了四种不同的免疫抑制方案：i）FK506（q12h）；ii）FK506（qd）+霉酚酸酯（PO；q12h，术后 7 天内）；iii）FK506（qd）+霉酚酸酯（IP；q12h，术后 7 天内）；iv）FK506（qd）+霉酚酸酯（IP；qd，术后 7 天内）。细胞移植后 3 周，系统评估了存活的人细胞数量。在接受 FK506（qd）和霉酚酸酯（IP；qd）治疗的动物中，观察到最多的移植细胞密度（每个脊髓切片平均有 915±95 个移植细胞）。大多数 hNUMA 阳性细胞与双皮质素（DCX）免疫反应性共定位。DCX 阳性神经元向周围宿主神经元进行广泛的轴突树突延伸。此外，在距移植物 500 μm 处鉴定到迁移的移植物细胞。在接受 FK506（q12h）、FK506（qd）+霉酚酸酯（PO；q12h）或 FK506（qd）+霉酚酸酯（IP；q12h）治疗的动物中，分别观察到 11.8±3.4%、61.2±7.8%和 99.4±8.9%[以 FK506（qd）和霉酚酸酯（IP；qd）的百分比表示]的细胞存活率。与接受 FK506+霉酚酸酯联合治疗的动物相比，仅接受 FK506 治疗的动物在注射部位附近鉴定出强 CD4/8 免疫反应性。这些数据表明，包括 FK506 和霉酚酸酯在内的联合、系统性递送的免疫抑制方案可显著提高 SOD1（G93A）大鼠脊髓内移植后人类脊髓干细胞的存活率。
