Risk of Early-Onset Sepsis following Preterm, Prolonged Rupture of Membranes with or without Chorioamnionitis.

OBJECTIVE: This study aims to determine whether preterm prolonged rupture of membranes (PPROM) increases the risk for early-onset sepsis (EOS) in preterm infants. STUDY DESIGN: Retrospective cohort study of infants 30 to 34 weeks' gestation from 2005 to 2014. Exposure to PPROM (rupture of membranes ≥ 18 hours) or chorioamnionitis (maternal temperature ≥ 38°C during delivery plus notation of chorioamnionitis in the medical record) was collected. The primary outcome was proven or suspected EOS. RESULTS: A total of 2,192 infants were included. Overall, 1,750 (80%) were not exposed to PPROM or chorioamnionitis (group 1), 381 (17%) were exposed to PPROM without chorioamnionitis (group 2), and 61 (3%) were exposed to chorioamnionitis ± PPROM (group 3). There was no difference in the incidence of proven or suspected EOS between groups 1 and 2 (5.4 vs. 5.5%, p = 0.86). Group 3 had a higher rate of EOS (24.6%) relative to groups 1 and 2 (p < 0.001). In multivariate analysis, risk of EOS was 4.1 times higher in infants exposed to chorioamnionitis. PPROM did not increase the risk of EOS in bivariate or multivariate analysis. CONCLUSION: In the absence of chorioamnionitis, PPROM does not increase the risk of proven or clinically suspected EOS in 30 to 34 weeks' gestation infants.

The effect of endogenous overexpression of hyaluronan synthases on material, morphological, and biochemical properties of uncrosslinked collagen biomaterials.

Hyaluronan is an essential component of the native extracellular matrix that has often been added exogenously to biomaterials. The role of endogenously produced hyaluronan on soft tensile tissue mechanics, however, has been largely overlooked. To investigate this aspect of hyaluronan using a cell-mediated approach, cells overexpressing the hyaluronan synthases (has), namely has-1, has-2, has-3 or the empty vector control LXSN, were seeded within collagen gel scaffolds. The resulting engineered tissues were grown under static tension for 6 weeks. Following 6 weeks of culture, the samples were characterized to assess collagen gel contraction, matrix organization, production of hyaluronan, and tissue material properties. The engineered tissues containing cells transfected to overexpress one of the has isozymes had significantly increased retention of hyaluronan within the scaffold; elevated hyaluronan secretion into the culture medium (all but has-2); reduced contraction; reduced collagen density; and significantly altered material properties compared to the LXSN controls. These results indicate that the cell-mediated endogenous overproduction of hyaluronan within biomaterials alters their material, morphological and biochemical characteristics. This investigation, the first to examine the role of endogenously produced hyaluronan in engineered tissue mechanics, suggests that overproduction of hyaluronan in soft connective tissues can transform their biological and biomechanical functionality.