OXIDATIVE DAMAGE AND PREMATURE RUPTURE OF THE MEMBRANES

越来越多的证据表明，早产儿绒毛膜羊膜早破（PPROM）是由于活性氧（ROS）引起的氧化损伤。来自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损伤羊膜上皮和胶原蛋白I（绒毛膜羊膜的最强组分）。用维生素C和E预处理绒毛膜羊膜可以阻断膜暴露于ROS时的破坏过程。维生素抗氧化剂治疗后OS暴露减少损害。我们认为，在怀孕期间增加维生素C和E的摄入量将保护绒毛膜羊膜并减少PPROM。作为第一步，我们必须表明，产科病人谁的经验PPROM表现出增加的证据，全身或区域氧化损伤。然后，我们必须证明，孕妇服用的维生素C和E的增加可以到达绒毛膜羊膜，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）将绘制ROS诱导的绒毛膜羊膜损伤的后遗症，特别关注维生素C和E影响成纤维细胞和羊膜上皮细胞损伤的作用，胶原蛋白溶解酶、金属蛋白酶（MMPS）及其组织抑制剂（TIMPS）的表达和释放的改变，胶原蛋白分解，膜拉伸强度和胶原蛋白修复。2)我们的临床试验将测试（具体目标2A）当与单独因早产（PTL）而入院的胎龄相当的患者（胎儿纤连蛋白+）或对照患者相比时，入院时具有记录的PPROM的患者是否表现出营养改变和全身性（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）的生物标志物证据增加。特定目标21中记录的PPROM患者将随机接受每日标准产前维生素单药治疗或每日产前维生素单药治疗或每日产前维生素强化维生素C和E治疗。维生素治疗期间的结果数据将包括系统和局部氧化应激的系列测量，宫颈阴道液中的胶原溶解活性，以及PPROM至分娩之间的间隔。分娩时，将获得母体和新生儿血液（脐带血）氧化损伤和抗氧化状态、维生素C和E水平以及绒毛膜羊膜抗张强度和膜维生素C浓度和新生儿结局的测量结果。这些体外研究和临床试验将提供关于增强维生素治疗保护绒毛膜羊膜价值的重要新信息。这也为抗氧化治疗预防PPROM的前瞻性研究奠定了基础。

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.