Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, California 94305-5454, USA.
JACC Cardiovasc Imaging. 2012 Jan;5(1):46-55. doi: 10.1016/j.jcmg.2011.07.011.
This study aims to provide insight into cellular kinetics using molecular imaging after different transplantation methods of bone marrow-derived mononuclear cells (MNCs) in a mouse model of peripheral artery disease (PAD).
MNC therapy is a promising treatment for PAD. Although clinical translation has already been established, there is a lack of knowledge about cell behavior after transplantation and about the mechanism whereby MNC therapy might ameliorate complaints of PAD.
MNCs were isolated from F6 transgenic mice (FVB background) that express firefly luciferase (Fluc) and green fluorescence protein (GFP). Male FVB and C57Bl6 mice (n = 50) underwent femoral artery ligation and were randomized into 4 groups receiving the following: 1) single intramuscular (IM) injection of 2 × 10(6) MNCs; 2) 4 weekly IM injections of 5 × 10(5) MNCs; 3) 2 × 10(6) MNCs intravenously; and 4) phosphate-buffered saline as control. Cells were characterized by flow cytometry and in vitro bioluminescence imaging (BLI). Cell survival, proliferation, and migration were monitored by in vivo BLI, which was validated by ex vivo BLI, post-mortem immunohistochemistry, and flow cytometry. Paw perfusion and neovascularization was measured with laser Doppler perfusion imaging (LDPI) and histology, respectively.
In vivo BLI revealed near-complete donor cell death 4 weeks after IM transplantation. After intravenous transplantation, BLI revealed that cells migrated to the injured area in the limb, as well as to the liver, spleen, and bone marrow. Ex vivo BLI showed presence of MNCs in the scar tissue and adductor muscle. However, no significant effects on neovascularization were observed, as monitored by LDPI and histology.
This is one of the first studies to assess kinetics of transplanted MNCs in PAD using in vivo molecular imaging. MNC survival is short-lived, MNCs do not preferentially home to injured areas, and MNCs do not significantly stimulate perfusion in this particular model.
本研究旨在通过分子影像学观察骨髓单核细胞（MNC）经不同移植方法在小鼠外周动脉疾病（PAD）模型中的细胞动力学变化。
MNC 治疗是 PAD 的一种有前途的治疗方法。尽管已经进行了临床转化，但对移植后细胞行为以及 MNC 治疗改善 PAD 症状的机制知之甚少。
从表达萤火虫荧光素酶（Fluc）和绿色荧光蛋白（GFP）的 F6 转基因小鼠（FVB 背景）中分离出 MNC。雄性 FVB 和 C57Bl6 小鼠（n=50）接受股动脉结扎，并随机分为 4 组，分别接受以下治疗：1）单次肌肉内（IM）注射 2×10（6）个 MNC；2）每周 4 次 IM 注射 5×10（5）个 MNC；3）静脉注射 2×10（6）个 MNC；4）磷酸盐缓冲液作为对照。通过流式细胞术和体外生物发光成像（BLI）对细胞进行特征分析。通过体内 BLI 监测细胞存活、增殖和迁移，并通过体外 BLI、死后免疫组织化学和流式细胞术进行验证。通过激光多普勒灌注成像（LDPI）和组织学分别测量足爪灌注和新生血管形成。
IM 移植后 4 周，体内 BLI 显示几乎完全的供体细胞死亡。静脉移植后，BLI 显示细胞迁移到肢体受损区域以及肝脏、脾脏和骨髓。体外 BLI 显示 MNC 存在于疤痕组织和内收肌中。然而，LDPI 和组织学监测并未观察到新生血管形成有显著影响。
这是使用体内分子成像评估 PAD 中移植 MNC 动力学的首批研究之一。MNC 存活时间短，MNC 不会优先归巢到受损区域，并且在这种特定模型中，MNC 不会显著刺激灌注。
