Department of Hand, Plastic and Reconstructive Surgery, Burn Center, BG Trauma Center Ludwigshafen, University of Heidelberg, Ludwigshafen, Germany.
Department of Head, Neck and Endocrine Surgery, Faculty of Medicine, University of Alexandria, Alexandria, Egypt.
PLoS One. 2022 Aug 11;17(8):e0272697. doi: 10.1371/journal.pone.0272697. eCollection 2022.
Inducing axial vascularisation of tissue engineering constructs is a well-established method to support tissue growth in large 3-dimensional tissues. Progenitor cell chemotaxis towards axially vascularized tissues has not been well characterized. In a prospective randomized controlled study including 32 male syngeneic Lewis rats we investigated the capability of the axially vascularized constructs to attract systemically injected bone marrow mononuclear cells (BMMNCs). The underlying mechanism for cell homing was investigated focusing on the role of hypoxia and the SDF1-CXCR4-7 axis. Sixteen animals were used as donors for BMMNCs. The other animals were subjected to implantation of a tissue engineering construct in the subcutaneous groin region. These constructs were axially vascularized either via an arteriovenous loop (AVL, n = 6) or via uninterrupted flow-through vessels (non-AVL, n = 10). BMMNCs were labelled with quantum dots (Qdot® 655) and injected 12 days after surgery either via intra-arterial or intravenous routes. 2 days after cell injection, the animals were sacrificed and examined using fluorescence microscopy. The Qdot® 655 signals were detected exclusively in the liver, spleen, AVL constructs and to a minimal extent in the non-AVL constructs. A significant difference could be detected between the number of labelled cells in the AVL and non-AVL constructs with more cells detected in the AVL constructs specially in central zones (p <0.0001). The immunohistological analysis showed a significant increase in the absolute expression of HIF-1 in the AVL group in comparison to the non-AVL group. The PCR analysis confirmed a 1.4-fold increase in HIF-1 expression in AVL constructs. Although PCR analysis showed an enhanced expression of CXCR4 and CXCR7 in AVL constructs, no significant differences in SDF1 expression were detected via immunohistological or PCR analysis. At the examined time point, the AVL constructs can attract BMMNCs in a mechanism probably related to the hypoxia associated with a robust tissue formation.
诱导组织工程构建物的轴向血管化是支持大 3 维组织中组织生长的一种成熟方法。祖细胞向轴向血管化组织的趋化作用尚未得到很好的描述。在一项包括 32 只雄性同基因 Lewis 大鼠的前瞻性随机对照研究中，我们研究了轴向血管化构建物吸引系统注射的骨髓单核细胞（BMMNC）的能力。我们研究了细胞归巢的潜在机制，重点关注缺氧和 SDF1-CXCR4-7 轴的作用。16 只动物被用作 BMMNC 的供体。其余动物在腹股沟皮下区域植入组织工程构建物。这些构建物通过动静脉环（AVL，n = 6）或连续血流通过的血管（非-AVL，n = 10）轴向血管化。BMMNC 用量子点（Qdot®655）标记，并在手术后 12 天通过动脉内或静脉内途径注射。细胞注射后 2 天，处死动物并使用荧光显微镜检查。仅在肝脏、脾脏、AVL 构建物中检测到 Qdot®655 信号，在非-AVL 构建物中检测到最小程度的信号。在 AVL 和非-AVL 构建物中标记细胞的数量之间可以检测到显著差异，特别是在中央区域中，AVL 构建物中检测到的细胞更多（p <0.0001）。免疫组织化学分析显示，与非-AVL 组相比，AVL 组中 HIF-1 的绝对表达显著增加。PCR 分析证实 AVL 构建物中 HIF-1 的表达增加了 1.4 倍。尽管 PCR 分析显示 AVL 构建物中 CXCR4 和 CXCR7 的表达增强，但通过免疫组织化学或 PCR 分析未检测到 SDF1 表达的显著差异。在所检查的时间点，AVL 构建物可以通过一种可能与强烈组织形成相关的缺氧机制吸引 BMMNC。
