OXIDATIVE DAMAGE AND PREMATURE RUPTURE OF THE MEMBRANES

越来越多的证据表明，早产羊膜早破(PPROM)是由活性氧(ROS)引起的氧化损伤所致。我们实验室的体外数据表明，在生理浓度下，ROS，次氯酸和超氧化物，确实会损伤羊膜上皮和绒毛膜最强的成分I型胶原。当胎膜暴露在ROS下时，用维生素C和E对绒毛膜羊膜进行预处理会阻止这种破坏过程。暴露于OS后的维生素抗氧化剂治疗可减少损害。我们认为，在怀孕期间增加维生素C和维生素E的摄入量将保护绒毛羊膜，减少胎膜早破。作为第一步，我们必须证明，经历胎膜早破的产科患者表现出更多全身或局部氧化损伤的证据。然后我们必须证明，当孕妇服用增加的维生素C和E时，可以到达绒毛膜并增加其抗氧化能力。这个项目有两个目标。1)我们的体外研究(1A-D)将描绘ROS引起的绒毛羊膜损伤的后遗症，特别关注维生素C和E对成纤维细胞和羊膜上皮细胞损伤的影响，胶原酶、金属蛋白酶(MMPs)及其组织抑制物(TIMPs)的表达和释放的变化，胶原的破坏，膜的拉伸强度和胶原修复。2)我们的临床试验将测试(特定目标2A)，与仅因早产(PTL)入院的胎龄相当的患者(胎儿纤维连接蛋白+)或与对照组患者相比，入院时有记录的PPROM患者是否表现出营养变化和全身(DNA加合物增加，总抗氧化能力降低)或局部氧化损伤(总抗氧化能力降低)的生物标志物证据。符合特定目标21的PPROM患者将被随机分为三组：单独服用每日标准产前维生素、单独服用每日维生素或每天服用维生素可增强维生素C和E。维生素治疗期间的结果数据将包括对全身和局部氧化应激、宫颈-阴道液中胶原酶活性以及PPROM从PPROM到分娩的间隔时间的一系列测量。分娩时，将测量孕妇和新生儿血液(脐带血)的氧化损伤和抗氧化状态，维生素C和E水平，以及绒毛羊膜抗张强度、膜维生素C浓度和新生儿结局。这些体外研究和临床试验将为加强维生素疗法保护绒毛羊膜的价值提供重要的新信息。这也将为抗氧化疗法预防PPROM的前瞻性研究奠定基础。

Increasing evidence suggests that preterm premature rupture of the chorioamnion membranes (PPROM) is attributable to oxidative damage resulting from reactive oxygen species (ROS). In-vitro data from our laboratory demonstrate that, in physiologic concentrations, the ROS, hypochlorous acid and superoxide, do damage amnion epithelium and collagen I, the strongest component of chorioamnion. Pretreatment of chorioamnion with vitamins C and E blocks the destructive processes when membranes then are exposed to ROS. Vitamin antioxidant treatment after OS-exposure reduces the damage. We believe that increased intake of vitamins C and E through pregnancy will protect the chorioamnion and decrease PPROM. As a first step, we must show that obstetric patients who experience PPROM demonstrate increased evidence of systemic or regional oxidative damage. We then must prove that increased vitamins C and E when taken by pregnant women reach the chorioamnion and increase its antioxidant capacity. This project has two goals. 1) Our in-vitro studies (1 A-D) will map the sequelae of ROS- induced damage of chorioamnion membranes with special attention to the role of vitamins C and E to influence fibroblast and amnion epithelial cell damage, alterations in expression and release of the collagenolytic enzymes, metalloproteinases (MMPS) and their tissue inhibitors (TIMPS), collagen breakdown, membrane tensile strength and collagen repair. 2) Our clinical trials will test (specific aim 2A) whether patients with documented PPROM on admission exhibit nutritional alterations and increased biomarker evidence of systemic (increased DNA adducts, decreased total antioxidant capacity) or local oxidative damage (decreased total anti-oxidant capacity) when compared with patients of comparable gestational age admitted for preterm labor (PTL) alone (fetal fibronectin+), or with control patients. Patients with documented PPROM from specific aim 21 will be randomized to daily standard prenatal vitamins alone or daily prenatal vitamins alone or daily prenatal vitamins plays enhanced vitamins C and E. Outcome data during vitamin treatment will include serial measures of systemic and local oxidative stress, collagenolytic activity in cervical-vaginal fluid, and interval between PPROM to delivery. At delivery, measures of maternal and newborn blood (cord blood) oxidative damage and antioxidant status, and vitamin C and E levels, as well as chorioamnion tensile strength and membrane vitamin C concentrations and neonatal outcome will be obtained. These in-vitro studies and clinical trials will provide important new information on the value of enhanced vitamin therapy to protect the chorioamnion. It also would lay the foundation for a prospective study of antioxidant therapy to prevent PPROM.