Department of Trauma Surgery, Johann Wolfgang Goethe University, Frankfurt am Main, Germany.
Langenbecks Arch Surg. 2011 Mar;396(3):379-87. doi: 10.1007/s00423-010-0626-1. Epub 2010 Mar 7.
CD133+CD34+ hematopoietic stem cells (HSCs) have been shown to differentiate into cell types of nonhematopoietic lineage. It is unclear whether HSCs target and repair damaged musculoskeletal tissue. We aimed to analyze if HSCs are mobilized after musculoskeletal surgery to circulation, home to surgical wound fluid (SWF)-activated endothelium, and are chemoattracted by SWF under in vitro conditions.
Circulating HSC levels were measured at t = 3, 8, 24, 48 h postoperatively using fluorescence-activated cell sorting (FACS) and compared with preoperative levels (t = 0) and normal volunteers. For adhesion experiments, HSCs were incubated on SWF-activated human umbilical vein endothelial cells (HUVECs) and HSC/HUVEC ratios determined by FACS. Adhesion receptor expression on HSC (L-selectin, lymphocyte function-associated antigen 1 (LFA-1), very late antigen-4) and SWF-activated HUVECs (P-selectin, E-selectin, V-cell adhesion molecules (CAM), I-CAM) was determined and HSC adhesion measured again after blocking upregulated receptors. Using a modified Boyden chamber, HSC chemotaxis was analyzed for an SWF and cytokine-neutralized SWF (vascular endothelial growth factor (VEGF), stromal-derived factor-1, interleukin-8) gradient.
Circulating HSCs were significantly increased 8 h after surgery. Increasing HSC adhesion to HUVECs was shown for SWF isolated at any postoperative time point, and chemoattraction was significantly induced in an SWF gradient with SWF isolated 8 and 24 h postoperatively. Receptor and cytokine blockade experiments with monoclonal antibodies revealed decreased HSC adhesion to SWF-activated endothelium and showed lower chemotaxis after blocking the LFA-1-I-CAM-1 receptor axis (adhesion) and neutralizing VEGF-165 (chemotaxis).
Our data demonstrate that HSCs are mobilized after trauma, target to wound-associated endothelium via the LFA-1-I-CAM-1 axis, and are chemoattracted by VEGF-165 under in vitro conditions.
已有研究表明，CD133+CD34+ 造血干细胞（HSCs）可分化为非造血谱系的细胞类型。但 HSCs 是否能靶向并修复受损的肌肉骨骼组织尚不清楚。本研究旨在分析 HSCs 是否在肌肉骨骼手术后动员到循环系统中，归巢到手术伤口液（SWF）激活的内皮细胞，并在体外条件下受 SWF 的趋化作用。
使用荧光激活细胞分选（FACS）术在术后 3、8、24 和 48 小时（t=3、8、24 和 48 小时）测量循环 HSC 水平，并与术前水平（t=0）和正常志愿者进行比较。为了进行黏附实验，将 HSCs 孵育在 SWF 激活的人脐静脉内皮细胞（HUVEC）上，并通过 FACS 确定 HSC/HUVEC 的比例。测定 HSC（L-选择素、淋巴细胞功能相关抗原 1（LFA-1）、非常晚期抗原-4）和 SWF 激活的 HUVEC（P-选择素、E-选择素、V 细胞黏附分子（CAM）、I-CAM）上黏附受体的表达，并在阻断上调的受体后再次测量 HSC 的黏附。使用改良 Boyden 室分析 SWF 和细胞因子中和的 SWF（血管内皮生长因子（VEGF）、基质衍生因子-1、白细胞介素-8）梯度的 HSC 趋化性。
手术后 8 小时，循环 HSCs 显著增加。从任何术后时间点分离的 SWF 均显示 HSC 与 HUVEC 的黏附增加，并且在术后 8 和 24 小时分离的 SWF 梯度中，趋化作用明显诱导。用单克隆抗体进行受体和细胞因子阻断实验表明，阻断 LFA-1-I-CAM-1 受体轴（黏附）和中和 VEGF-165（趋化）后，HSC 与 SWF 激活的内皮细胞的黏附减少，趋化作用降低。
我们的数据表明，HSCs 在创伤后被动员，通过 LFA-1-I-CAM-1 轴靶向与伤口相关的内皮细胞，并在体外条件下受 VEGF-165 的趋化作用。
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