Department of Biomedical Engineering, Tulane University, New Orleans, Louisiana 70118-5698, USA.
Anat Rec (Hoboken). 2010 Oct;293(10):1629-38. doi: 10.1002/ar.21195. Epub 2010 Jul 20.
Analyses of microvascular networks with traditional tracer filling techniques suggest that the blood and lymphatic systems are distinct without direct communications, yet involvement of common growth factors during angiogenesis and lymphangiogenesis suggest that interactions at the capillary level are possible. To investigate the structural basis for lymphatic/blood endothelial cell connections during normal physiological growth, the objective of this study was to characterize the spatial relations between lymphatic and blood capillaries in adult rat mesenteric tissue. Using immunohistochemical methods, adult male Wistar rat mesenteric tissues were labeled with antibodies against PECAM (an endothelial marker) and LYVE-1, Prox-1, or Podoplanin (lymphatic endothelial markers) or NG2 (a pericyte marker). Positive PECAM labeling identified apparent lymphatic/blood endothelial cell connections at the capillary level characterized by direct contact or direct alignment with one another. In PECAM labeled networks, a subset of the lymphatic and blood capillary blind ends were connected with each other. Intravital imaging of FITC-Albumin injected through the femoral vein did not identify lymphatic vessels. At contact sites, lymphatic endothelial markers did not extend along blood capillary segments. However, PECAM positive lymphatic sprouts, structurally similar to blood capillary sprouts, lacked observable lymphatic marker labeling. These observations suggest that nonlumenal lymphatic/blood endothelial cell interactions exist in unstimulated adult microvascular networks and highlight the potential for lymphatic/blood endothelial cell plasticity.
利用传统示踪剂填充技术对微血管网络进行分析表明，血液系统和淋巴系统是相互独立的，没有直接的交流，但在血管生成和淋巴管生成过程中共同涉及生长因子表明，毛细血管水平的相互作用是可能的。为了研究正常生理生长过程中淋巴管/血管内皮细胞连接的结构基础，本研究的目的是描述成年大鼠肠系膜组织中淋巴管和毛细血管之间的空间关系。使用免疫组织化学方法，用针对 PECAM（内皮标记物）和 LYVE-1、Prox-1 或 Podoplanin（淋巴管内皮标记物）或 NG2（周细胞标记物）的抗体对成年雄性 Wistar 大鼠肠系膜组织进行标记。阳性 PECAM 标记鉴定出毛细血管水平上的淋巴管/血管内皮细胞连接，其特征为直接接触或彼此直接对齐。在 PECAM 标记的网络中，一部分淋巴管和毛细血管盲端相互连接。通过股静脉注射 FITC-白蛋白进行的活体成像并未识别出淋巴管。在接触部位，淋巴管内皮标记物并未沿毛细血管段延伸。然而，结构上类似于毛细血管芽的 PECAM 阳性淋巴管芽缺乏可观察到的淋巴管标记物标记。这些观察结果表明，在未受刺激的成年微血管网络中存在非腔淋巴管/血管内皮细胞相互作用，并强调了淋巴管/血管内皮细胞可塑性的潜力。
