Faranak Behnia

Chorioamniotic membrane senescence: a signal for parturition?

OBJECTIVE Senescence is an important biological phenomenon involved in both physiologic and pathologic processes. We propose that chorioamniotic membrane senescence is a mechanism associated with human parturition. The present study was conducted to explore the association between senescence and normal term parturition by examining the morphologic and biochemical evidences in chorioamniotic membranes. STUDY DESIGN Chorioamniotic membranes were collected from normal term deliveries; group 1: term labor and group 2: term, not in labor. Senescence-related morphologic changes were determined by transmission electron microscopy and biochemical changes were studied by senescence-associated (SA) β-galactosidase staining. Amniotic fluid samples collected from both term labor and term not in labor were analyzed for 14 SA secretory phenotype (SASP) markers. RESULTS Morphologic evidence of cellular senescence (enlarged cells and organelles) and a higher number of SA β-galactosidase-stained amnion and chorion cells were observed in chorioamniotic membranes obtained from women in labor at term, when compared to term not in labor. The concentration of proinflammatory SASP markers (granulocyte macrophage colony-stimulating factor, interleukin-6 and -8) was significantly higher in the amniotic fluid of women in labor at term than women not in labor. In contrast, SASP factors that protect against cell death (eotaxin-1, soluble Fas ligand, osteoprotegerin, and intercellular adhesion molecule-1) were significantly lower in the amniotic fluid samples from term labor. CONCLUSION Morphologic and biochemical features of senescence were more frequent in chorioamniotic membranes from women who experienced term labor. Senescence of chorioamniotic membranes were also associated with amniotic fluid SASP markers.

Oxidative stress damage-associated molecular signaling pathways differentiate spontaneous preterm birth and preterm premature rupture of the membranes.

STUDY HYPOTHESIS In women with preterm premature rupture of the membranes (PPROM), increased oxidative stress may accelerate premature cellular senescence, senescence-associated inflammation and proteolysis, which may predispose them to rupture. STUDY FINDING We demonstrate mechanistic differences between preterm birth (PTB) and PPROM by revealing differences in fetal membrane redox status, oxidative stress-induced damage, distinct signaling pathways and senescence activation. WHAT IS KNOWN ALREADY Oxidative stress-associated fetal membrane damage and cell cycle arrest determine adverse pregnancy outcomes, such as spontaneous PTB and PPROM. STUDY DESIGN, SAMPLES/MATERIALS, METHODS Fetal membranes and amniotic fluid samples were collected from women with PTB and PPROM. Molecular, biochemical and histologic markers were used to document differences in oxidative stress and antioxidant enzyme status, DNA damage, secondary signaling activation by Ras-GTPase and mitogen-activated protein kinases, and activation of senescence between membranes from the two groups. MAIN RESULTS AND THE ROLE OF CHANCE Oxidative stress was higher and antioxidant enzymes were lower in PPROM compared with PTB. PTB membranes had minimal DNA damage and showed activation of Ras-GTPase and ERK/JNK signaling pathway with minimal signs of senescence. PPROM had higher numbers of cells with DNA damage, prosenescence stress kinase (p38 MAPK) activation and signs of senescence. LIMITATIONS, REASONS FOR CAUTION Samples were obtained retrospectively after delivery. The markers of senescence that we tested are specific but are not sufficient to confirm senescence as the pathology in PPROM. WIDER IMPLICATIONS OF THE FINDINGS Oxidative stress-induced DNA damage and senescence are characteristics of fetal membranes from PPROM, compared with PTB with intact membranes. PTB and PPROM arise from distinct pathophysiologic pathways. Oxidative stress and oxidative stress-induced cellular damages are likely determinants of the mechanistic signaling pathways and phenotypic outcome. STUDY FUNDING AND COMPETING INTERESTS This study is supported by developmental funds to Dr R. Menon from the Department of Obstetrics and Gynecology at The University of Texas Medical Branch at Galveston and funds to Dr M. Kacerovský from the Ministry of Health Czech Republic (UHHK, 001799906). The authors report no conflict of interest.

Telomere fragment induced amnion cell senescence: A contributor to parturition?

Oxidative stress (OS)-induced senescence of the amniochorion has been associated with parturition at term. We investigated whether telomere fragments shed into the amniotic fluid (AF) correlated with labor status and tested if exogenous telomere fragments (T-oligos) could induce human and murine amnion cell senescence. In a cross-sectional clinical study, AF telomere fragment concentrations quantitated by a validated real-time PCR assay were higher in women in labor at term compared to those not in labor. In vitro treatment of primary human amnion epithelial cells with 40 μM T-oligos ([TTAGGG]2) that mimic telomere fragments, activated p38MAPK, produced senescence-associated (SA) β-gal staining and increased interleukin (IL)-6 and IL-8 production compared to cells treated with complementary DNA sequences (Cont-oligos, [AATCCC]2). T-oligos injected into the uteri of pregnant CD1 mice on day 14 of gestation, led to increased p38MAPK, SA-β-gal (SA β-gal) staining in murine amniotic sacs and higher AF IL-8 levels on day 18, compared to saline treated controls. In summary, term labor AF samples had higher telomere fragments than term not in labor AF. In vitro and in situ telomere fragments increased human and murine amnion p38MAPK, senescence and inflammatory cytokines. We propose that telomere fragments released from senescent fetal cells are indicative of fetal cell aging. Based on our data, these telomere fragments cause oxidative stress associated damages to the term amniotic sac and force them to release other DAMPS, which, in turn, provide a sterile immune response that may be one of the many inflammatory signals required to initiate parturition at term.

Mechanistic Differences Leading to Infectious and Sterile Inflammation

Inflammation is a physiologic component of pregnancy and parturition. Overwhelming intrauterine inflammatory load promotes quiescent feto‐maternal tissues into a contractile phenotype. Like inflammation, oxidative stress is an inevitable component of both pregnancy and parturition. Pathologic activation of host innate immune response to adverse pregnancy conditions can lead to premature activation of inflammatory and oxidative stress. Inflammation and oxidative stress markers seen with both sterile and infectious inflammation are often similar; therefore, it is difficult to understand causality of conditions like spontaneous preterm birth. This review demonstrates potential mechanistic pathways of activation of sterile and infectious inflammation. We demonstrate the activation of two unique pathways of inflammation by factors that are well‐documented proxies for oxidative stress (cigarette smoke extract) and infection (lipopolysaccharide). Sterile inflammation seen after exposure to an oxidative stress inducer is due to cellular elemental damage resulting in p38 mitogen‐activated protein kinase (MAPK) induced cellular senescence. Infectious inflammation is through activation of transcription factor NF‐κB and independent of oxidative stress‐associated damages and p38 MAPK‐induced senescence. Understanding the differences in the inflammatory pathway activation by various risk factors is important to design better screening, diagnostic and intervention strategies to reduce the risks of adverse pregnancy outcomes.

Aging of intrauterine tissues in spontaneous preterm birth and preterm premature rupture of the membranes: A systematic review of the literature

BACKGROUND Many adverse pregnancy outcomes (APOs), including spontaneous preterm birth (PTB), are associated with placental dysfunction. Recent clinical and experimental evidences suggest that premature aging of the placenta may be involved in these events. Although placental aging is a well-known concept, the mechanisms of aging during normal pregnancy and premature aging in APOs are still unclear. This review was conducted to assess the knowledge on placental aging related biochemical changes leading to placental dysfunction in PTB and/or preterm premature rupture of membranes (pPROM). METHODS We performed a systematic review of studies published over the last 50 years in two electronic databases (Pubmed and Embase) on placental aging and PTB or pPROM. RESULTS The search yielded 554 citations, 30 relevant studies were selected for full-text review and three were included in the review. Only one study reported oxidative stress-related aging and degenerative changes in human placental membranes and telomere length reduction in fetal cells as part of PTB and/or pPROM mechanisms. Similarly, two animal studies reported findings of decidual senescence and referred to PTB mechanisms. CONCLUSION Placental and fetal membrane oxidative damage and telomere reduction are linked to premature aging in PTB and pPROM but the risk factors and biomolecular pathways causing this phenomenon are not established in the literature. However, no biomarkers or clinical indicators of premature aging as a pathology of PTB and pPROM have been reported. We document major knowledge gaps and propose several areas for future research to improve our understanding of premature aging linked to placental dysfunction.

Environmental Pollutant Polybrominated Diphenyl Ether, a Flame Retardant, Induces Primary Amnion Cell Senescence

Polybrominated diphenyl ethers (PBDEs) are documented to increase the risk for spontaneous preterm birth (PTB). We hypothesize that PBDEs cause oxidative stress (OS) that leads to fetal cell senescence and inflammation associated with PTB.

High bisphenol A (BPA) concentration in the maternal, but not fetal, compartment increases the risk of spontaneous preterm delivery

Abstract Objective: The objective of this study is to determine if BPA exposure, as measured by maternal plasma (MP) and amniotic fluid (AF) BPA concentrations is associated with an increased risk of spontaneous preterm birth (PTB) and preterm premature rupture of membranes (pPROM). Methods: In this nested case–control study, MP samples from women in term labor (n = 30), preterm labor that ended with preterm delivery (n = 25), or who had pPROM (n = 30) and amniotic fluid samples from term labor (n= 45), preterm labor (n = 60), and pPROM (n = 35) were assayed for BPA by enzyme immunoassay. Results: BPA was detectible in 100% of MP and AF samples. Women with MP BPA concentrations in the fourth quartile were at increased risk of PTB (cOR = 4.12, 95% CI = 1.32–12.87; aOR = 4.78, 95% CI = 1.14–20) but not pPROM. High (fourth quartile) AF BPA values also tended to increase the risk of pPROM (cOR = 2.47, 95% CI = 0.96–6.37) but results were not statistically significant. Conclusions: Increased BPA concentration is associated with an increased risk for PTB or pPROM depending on the maternal–fetal compartment(s) affected. High MP plasma BPA concentrations are associated with PTB with intact membranes but high AF BPA concentrations may weakly be associated with pPROM.

Vitamin D and corticotropin-releasing hormone in term and preterm birth: potential contributions to preterm labor and birth outcome

Abstract Background: Poor maternal vitamin D status and elevated circulating corticotropin-releasing hormone (CRH) are associated with preterm birth. It is not known if these risk factors are independent or interrelated. Both are associated with inflammation. Methods: We measured maternal circulating 25-hydroxyvitamin D (25-OH-D) and CRH from 97 samples collected from 15 early-preterm, 31 late-preterm, 21 early-term, and 30 term births. The potential involvement of vitamin D in the regulation of inflammation was evaluated by Q-PCR in human uterine smooth muscle (UTSM) cell line. Results: Maternal 25-OH-D was lowest in early-preterm births (22.9 ± 4.2 ng/ml versus 34.4 ± 1.4 ng/ml; p = .029). Circulating CRH was high in early-preterm births (397 ± 30 pg/ml). Late-preterm (304 ± 13 pg/ml) and early-term births (347 ± 17 pg/ml) were not different from term births (367 ± 19 pg/ml), after accounting for gestational age. Maternal circulating 25-OH-D and CRH were not associated in term births. In preterm births, 25-OH-D below 30 ng/ml was associated with higher CRH. Vitamin D treatment of UTSM significantly reduced mRNA for leptin and IL-6 receptors. Deletion of vitamin D receptor from UTSM promoted the expression of the cox2 inflammatory marker. Conclusion: Early-preterm birth showed a syndrome of high maternal CRH and low vitamin D status.

Perinatal Outcomes after Short versus Prolonged Indomethacin for Tocolysis in Women with Preterm Labor

Objective Indomethacin tocolysis is generally limited to 48 hours. Indomethacin has been administered for longer durations to prolong gestation in extreme prematurity. Our aim is to compare perinatal outcomes after a prolonged course, > 48 hours versus ≤  48 hours in preterm labor. Methods A retrospective chart review of women admitted with preterm labor < 32 weeks gestation who received indomethacin for tocolysis. The primary maternal outcome was latency from admission until delivery. The primary neonatal outcome was a composite of severe neonatal morbidities. Results A total of 73 women were included: 32 (43.8%) received indomethacin for > 48 hours (prolonged) and 41 (56.2%) for ≤ 48 hours (standard). Prolonged group started on indomethacin at an earlier gestational age compared with standard group (23.9 [23.1-27.3] vs. 25.7 [23.8-28.5] weeks, p = 0.03). Latency from admission until delivery was longer in the prolonged group versus the standard group (1.8 [1.1-3] vs. 0.4 [0.1-0.8] weeks, p < 0.001). Prolonged use was not associated with increased risk of the composite neonatal outcome; however, there was a trend for more necrotizing enterocolitis. Conclusion A prolonged course of indomethacin may be an option for women with preterm labor at risk of extreme prematurity; it may also be associated with higher risks of some adverse neonatal outcomes.

Hemostatic Resuscitation in Peripartum Hysterectomy Pre- and Postmassive Transfusion Protocol Initiation

Background Massive transfusion protocols (MTPs) have been examined in trauma. The exact ratio of packed red blood cells (PRBC) to other blood replacement components in hemostatic resuscitation in obstetrics has not been well defined. Objective The objective of this study was to evaluate hemostatic resuscitation in peripartum hysterectomy comparing pre‐ and postinstitution of a MTP. Study Design We conducted a retrospective, descriptive study of women undergoing peripartum hysterectomies from January 2002 to January 2015 who received ≥ 4 units of PRBC. Individuals were grouped into either a pre‐MTP institution group or a post‐MTP institution group. The post‐MTP group was subdivided into those who had the protocol activated (MTP) versus not activated (no MTP). Primary outcomes were estimated blood loss (EBL) and need for blood product replacement. The secondary outcome was a composite of maternal morbidity, including need for mechanical ventilation, venous thromboembolism, pulmonary edema, acute kidney injury, and postpartum infection. A Mann‐Whitney U test was used to compare continuous variables, and a chi‐squared test was used for categorical variables with significance of p < 0.05. Results Of the 165 women who had a peripartum hysterectomy during the study period, 62 received four units or more of PRBC. No significant differences were noted in EBL or blood product replacement between the pre‐MTP (n = 39) and post‐MTP (n = 23) groups. Similarly, the MTP (n = 6) and no MTP (n = 17) subgroups showed no significant difference between EBL and overall blood product replacement. Significant differences were seen in transfusion of individual blood products, such as fresh frozen plasma (FFP) (MTP = 4, no MTP = 2; p = 0.02) and platelets (plts) (MTP = 6, no MTP = 0; p = 0.03). The use of high ratio replacement therapy for both plasma and plts was more common in the MTP group (FFP/PRBC ratio [MTP = 0.5, no MTP = 0.3; p = 0.02]; plts/PRBC ratio [MTP = 0.7, no MTP = 0; p = 0.03]). There were no differences in the secondary outcome between pre‐ and post‐MTP or MTP and no MTP. Conclusion Initiation of the MTP did result in an increase in transfusion of FFP and plts intraoperatively. At our institution, the MTP is underutilized, but it appears that providers are more cognizant of the use of high transfusion ratios.