Incorporation of Endothelial Progenitor Cells into Placental Vaculature

描述(申请人提供)：成功的胎盘发育对成年人的健康有长期的影响，对胚胎存活和胎儿的正常生长是必要的，并依赖于血管形成。在妊娠期间，胎盘血管延长、扩张和延伸新芽，以促进营养物质从母体最大限度地转移到胎盘血管，为发育中的胚胎/胎儿提供血液支持。长期的研究目标是确定和确定促进胎盘内血管生长的生理途径。内皮祖细胞(EPC)存在于骨髓中，迁移并结合到生长的血管中形成新的内皮细胞。内皮祖细胞与肺动脉高压、心血管风险、缺血、动脉粥样硬化和妊娠之间的关系已经确定。先兆子痫和妊娠期糖尿病患者的EPC数量减少，而母亲胰岛素治疗增加了糖尿病妊娠期间的EPC数量。我们从新生猪的外周血中分离并鉴定了内皮祖细胞。这些内皮祖细胞表达整合素，并利用这些跨膜受体在体外黏附和迁移到骨桥蛋白(OPN)上。骨桥蛋白是一种细胞外基质分子，在人和猪的胎盘中都有显著表达。当内皮祖细胞作为单分子层单独培养在添加了血管生成因子的3D胶原基质表面时，它们无法侵入基质。然而，如果与成人脐静脉内皮细胞(HUVECs)培养，HUVECs侵入基质并形成血管结构，内皮祖细胞就会整合到这些血管结构中。这与它们在体内的行为相似。重要的是，OPN剂量依赖地增加合并到这些血管结构中的内皮祖细胞的数量。中心假设是骨桥蛋白将内皮祖细胞招募到胎盘内新生血管的部位。一旦到达，内皮祖细胞就通过连接黏附分子(即缝隙连接、紧密连接和黏附连接)直接与成年内皮细胞沟通，从而结合到生长中的血管中。这两个目标是：(1)确定允许内皮祖细胞整合到已建立的血管系统中的细胞间信号；(2)确定内皮祖细胞是否整合到猪胎盘血管网络中。这些目标的完成将有助于合理设计和开发新的静脉内EPC疗法，以使胎盘血管系统正常化，并减少先兆子痫、妊娠期糖尿病和其他妊娠疾病的影响。

DESCRIPTION (provided by applicant): Successful placental development has long-term implications for adult health, is necessary for embryo survival and proper fetal growth, and is dependent on vascularization. During pregnancy, placental blood vessels elongate, dilate, and extend new sprouts to facilitate maximal transfer of nutrients from maternal to placental vasculatures for hematotrophic support of the developing embryo/fetus. The long-term research goal is to identify and determine the physiological pathways that promote vessel growth within the placenta. Endothelial Progenitor Cells (EPCs) reside in the bone marrow, migrate, and incorporate into growing blood vessels to form new endothelial cells. A firm relationship has been established between EPCs and pulmonary hypertension, cardiovascular risk, ischemia, atherosclerosis, and pregnancy. EPC numbers decrease in preeclampsia and gestational diabetes, and maternal insulin therapy increases EPC numbers during diabetic pregnancy. We have isolated and characterized EPCs from the peripheral blood of newborn pigs. These EPCs express integrins, and use these transmembrane receptors to adhere and migrate in vitro on osteopontin (OPN) an extracellular matrix molecule with prominent expression in the placenta of both humans and pigs. When EPCs are cultured alone as a monolayer on the surface of 3D collagen matrices supplemented with angiogenic factors, they fail to invade the matrix. However, if cultured with adult human umbilical vein endothelial cells (HUVECs), which invade the matrix and form vascular structures, the EPCs incorporate into these vascular structures. This is similar to their behavior in vivo. Importantly, OPN dose-dependently increases the number of EPCs that incorporate into these vascular structures. The central hypothesis is that OPN recruits EPCs to sites of neovascularization within the placenta. Once there, EPCs communicate directly with adult endothelial cells via junctional adhesion molecules (i.e., gap, tight and adherens junctions) to incorporate into growing vessels. The two objectives are: (1) Determine the intercellular signals that allow EPCs to incorporate into established vasculature; and (2) Determine whether EPCs incorporate into placental vascular networks pigs. Completion of these objectives will aid the rational design and development of novel intravenous EPC-based therapies to normalize placental vasculature, and lessen effects of preeclampsia, gestational diabetes, and other gestational diseases.