Comparison of the mechanisms responsible for cervical remodeling in preterm and term labor

Abstract

Understanding the mechanisms of term and preterm cervical remodeling is essential to prevent prematurity. Is preterm cervical remodeling caused by the same mechanisms that cause cervical remodeling at term, and are these changes accelerated in time? This question has been pondered by obstetricians seeking for strategies to prevent preterm labor for many years. Mice represent an informative model of preterm birth. Thus, in this review we will discuss the recent findings from mouse models that identify and characterize the initiators and cellular effectors of cervical remodeling at term and preterm delivery. These studies suggest that similarities and differences exist between term and preterm cervical remodeling. Complement is an initiator or mediator in preterm delivery but is not involved in the physiological process that leads to term delivery. Therefore, complement constitutes a specific and selective target for potentially preventing preterm delivery, thus improving neonatal health.

Prevention of preterm birth: Harnessing science to address the global epidemic

“…Many of the biochemical changes that take place physiologically within the cervix may be different between term or preterm tissues (80). Nonetheless, the final common pathway triggered by inflammatory mediators is degradation of collagen fibers by MMPs (mainly MMP-2 and -9), with changes in collagen organization, decreased fiber density, and cervical ripening (81). How extracellular tissue remodeling within the cervix interacts with the cervical smooth muscle and fibroblasts to influence tissue architecture remains unknown.…”

An elevated amniotic fluid prostaglandin F2αconcentration is associated with intra-amniotic inflammation/infection, and clinical and histologic chorioamnionitis, as well as impending preterm delivery in patients with preterm labor and intact membranes

“…Two-thirds of all preterm births result from spontaneous preterm labor [12], a syndrome [13–17] characterized by the combination of increased uterine contractility [18–20], cervical remodeling [21–28], and/or activation of the chorioamniotic membranes and decidua [29–32]. …”

Associação entre fatores genéticos e risco aumentado de prematuridade em pacientes com antecedente de incompetência cervical

“…A importância do colo uterino para o advento do nascimento prematuro já foi extensamente avaliada e reportada em diversos estudos (2,38) . Uma das formas de avaliar o colo é pela ultrassonografia transvaginal.…”

“…Tais modificações alertam para a possibilidade de associação entre os genes relacionados às conexões da matriz celular e a incompetência cervical do colo, que vai levar também à prematuridade (38) .…”

“…Esse remodelamento é direcionado pela qualidade e quantidade das fibras do colágeno e outras substâncias da matriz extracelular e sua interposição, que influem diretamente no comportamento biomecânico da cérvice, inclusive em condições patológicas, como na incompetência cervical (38) .…”