Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
Department of Orthopaedic Surgery and Joint Surgery Center, Takatsuki General Hospital, Osaka, Japan.
Stem Cell Res Ther. 2024 Sep 27;15(1):325. doi: 10.1186/s13287-024-03946-3.
The uncultured adipose-derived stromal vascular fraction (SVF), consisting of adipose-derived stromal cells (ADSCs), M2 macrophages (M2Φ) and others, has shown therapeutic potential against osteoarthritis (OA), however, the mechanisms underlying its therapeutic effects remain unclear. Therefore, this study investigated the effects of the SVF on OA in a human-immunodeficient rat xenotransplantation model.
OA model was induced in the knees of female immunodeficient rats by destabilization of the medial meniscus. Immediately after the surgery, human SVF (1 × 10), ADSCs (1 × 10), or phosphate buffered saline as a control group were transplanted into the knees. At 4 and 8 weeks postoperatively, OA progression and synovitis were analyzed by macroscopic and histological analyses, and the expression of collagen II, SOX9, MMP-13, ADAMTS-5, F4/80, CD86 (M1), CD163 (M2), and human nuclear antigen (hNA) were evaluated immunohistochemically. In vitro, flow cytometry was performed to collect CD163-positive cells as M2Φ from the SVF. Chondrocyte pellets (1 × 10) were co-cultured with SVF (1 × 10), M2Φ (1 × 10), and ADSCs (1 × 10) or alone as a control group, and the pellet size was compared. TGF-β, IL-10 and MMP-13 concentrations in the medium were evaluated using enzyme-linked immunosorbent assay.
In comparison with the control and ADSC groups, the SVF group showed significantly slower OA progression and less synovitis with higher expression of collagen II and SOX9, lower expression of MMP-13 and ADAMTS-5, and lower F4/80 and M1/M2 ratio in the synovium. Only the SVF group showed partial expression of hNA-, CD163-, and F4/80-positive cells in the rat synovium. In vitro, the SVF, M2Φ, ADSC and control groups, in that order, showed larger pellet sizes, higher TGF-β and IL-10, and lower MMP-13 concentrations.
The M2Φ in the transplanted SVF directly affected recipient tissue, enhancing the secretion of growth factors and chondrocyte-protecting cytokines, and partially improving chondrocytes and joint homeostasis. These findings indicate that the SVF is as an effective option for regenerative therapy for OA, with mechanisms different from those of ADSCs.
未培养的脂肪来源的基质血管部分（SVF），由脂肪来源的基质细胞（ADSCs）、M2 巨噬细胞（M2Φ）等组成，对骨关节炎（OA）具有治疗潜力，但其治疗效果的机制尚不清楚。因此，本研究通过人免疫缺陷大鼠异种移植模型研究了 SVF 对 OA 的影响。
通过内侧半月板不稳定术在雌性免疫缺陷大鼠膝关节中诱导 OA 模型。手术后立即将人 SVF（1×10）、ADSCs（1×10）或磷酸盐缓冲盐水作为对照组移植到膝关节中。术后 4 和 8 周，通过大体和组织学分析分析 OA 进展和滑膜炎，并通过免疫组织化学评估胶原 II、SOX9、MMP-13、ADAMTS-5、F4/80、CD86（M1）、CD163（M2）和人核抗原（hNA）的表达。在体外，通过流式细胞术从 SVF 中收集 CD163 阳性细胞作为 M2Φ。将软骨细胞小珠（1×10）与 SVF（1×10）、M2Φ（1×10）和 ADSCs（1×10）共培养或单独作为对照组，比较小珠大小。使用酶联免疫吸附试验评估培养基中 TGF-β、IL-10 和 MMP-13 的浓度。
与对照组和 ADSC 组相比，SVF 组 OA 进展较慢，滑膜炎较轻，胶原 II 和 SOX9 表达较高，MMP-13 和 ADAMTS-5 表达较低，滑膜中 F4/80 和 M1/M2 比值较低。只有 SVF 组在大鼠滑膜中部分表达 hNA-、CD163-和 F4/80-阳性细胞。在体外，SVF、M2Φ、ADSC 和对照组依次显示出较大的小珠尺寸、较高的 TGF-β 和 IL-10 以及较低的 MMP-13 浓度。
移植的 SVF 中的 M2Φ 直接影响受者组织，增强生长因子和软骨细胞保护细胞因子的分泌，并在一定程度上改善软骨细胞和关节内稳态。这些发现表明 SVF 是 OA 再生治疗的有效选择，其机制与 ADSC 不同。
