Felipe Vadillo-Ortega

Increased matrix metalloproteinase activity and reduced tissue inhibitor of metalloproteinases-1 levels in amniotic fluids from pregnancies complicated by premature rupture of membranes.

OBJECTIVES It has been suggested that increased matrix metalloproteinases activity promotes the weakening of the amniochorion during normal and premature rupture of membranes. This study was designed to determine whether levels of matrix metalloproteinases and the tissue inhibitor of metalloproteinases-1 in amniotic fluid change in a pattern consistent with this hypothesis. STUDY DESIGN Gelatinolytic activity, measured by a soluble substrate assay and zymography, and the concentrations of tissue inhibitor of metalloproteinases-1 were estimated in amniotic fluid obtained from (1) normal early gestations, (2) normal term pregnancies with labor, (3) normal term pregnancies without labor, and (4) pregnancies complicated by premature rupture of membranes. The 92 kd type IV collagenase (matrix metalloproteinase-9) was also detected in amniotic fluid by Western blotting. RESULTS Matrix metalloproteinase activities were higher in amniotic fluid from normal term pregnancies with labor and pregnancies complicated by premature rupture of membranes than from early pregnancies and term gestations without labor. The amniotic fluid from term pregnancies with labor or pregnancies with premature rupture of membranes contained several gelatinases, as revealed by zymography. The major amniotic fluid gelatinolytic activity in premature rupture of membranes and term pregnancies with labor corresponded to matrix metalloproteinase-9. Tissue inhibitor of metalloproteinases-1 concentrations were highest in early-pregnancy amniotic fluid, followed by term gestation with labor, term gestation without labor, and premature rupture of membranes. CONCLUSIONS Normal labor and premature rupture of membranes are associated with increased levels of matrix metalloproteinases, particularly matrix metalloproteinase-9 in amniotic fluid. Premature rupture of membranes is associated with reduced levels of tissue inhibitor of metalloproteinases-1. The imbalance between matrix metalloproteinases and tissue inhibitor of metalloproteinases-1 in amniotic fluid may reflect a disorder that promotes premature rupture of membranes.

Effect of supplementation during pregnancy with L-arginine and antioxidant vitamins in medical food on pre-eclampsia in high risk population: randomised controlled trial

Objective To test the hypothesis that a relative deficiency in L-arginine, the substrate for synthesis of the vasodilatory gas nitric oxide, may be associated with the development of pre-eclampsia in a population at high risk. Design Randomised, blinded, placebo controlled clinical trial. Setting Tertiary public hospital in Mexico City. Participants Pregnant women with a history of a previous pregnancy complicated by pre-eclampsia, or pre-eclampsia in a first degree relative, and deemed to be at increased risk of recurrence of the disease were studied from week 14-32 of gestation and followed until delivery. Interventions Supplementation with a medical food—bars containing L-arginine plus antioxidant vitamins, antioxidant vitamins alone, or placebo—during pregnancy. Main outcome measure Development of pre-eclampsia/eclampsia. Results 222 women were allocated to the placebo group, 228 received L-arginine plus antioxidant vitamins, and 222 received antioxidant vitamins alone. Women had 4-8 prenatal visits while receiving the bars. The incidence of pre-eclampsia was reduced significantly (χ2=19.41; P<0.001) in women randomised to L-arginine plus antioxidant vitamins compared with placebo (absolute risk reduction 0.17 (95% confidence interval 0.12 to 0.21). Antioxidant vitamins alone showed an observed benefit, but this effect was not statistically significant compared with placebo (χ2=3.76; P=0.052; absolute risk reduction 0.07, 0.005 to 0.15). L-arginine plus antioxidant vitamins compared with antioxidant vitamins alone resulted in a significant effect (P=0.004; absolute risk reduction 0.09, 0.05 to 0.14). Conclusions Supplementation during pregnancy with a medical food containing L-arginine and antioxidant vitamins reduced the incidence of pre-eclampsia in a population at high risk of the condition. Antioxidant vitamins alone did not have a protective effect for prevention of pre-eclampsia. Supplementation with L-arginine plus antioxidant vitamins needs to be evaluated in a low risk population to determine the generalisability of the protective effect, and the relative contributions of L-arginine and antioxidant vitamins to the observed effects of the combined treatment need to be determined. Trial registration Clinical trials NCT00469846.

Role of matrix metalloproteinases in preterm labour

Extracellular matrix homeostasis is a key process in the maintenance of the tensile strength of the amniochorion. This tensile strength guarantees the role of the membranes as a physical and functional boundary for the fetus during human pregnancy. Pathological rupture of these structures before 37 completed weeks of gestation is known as preterm prelabour rupture of the membranes (PPROM) and it is a major cause of spontaneous preterm labour and preterm birth. A mechanism involving the activation of matrix metalloproteinases (MMP)‐9, a 92‐kDa type IV collagenase, as an essential mediator of tissue damage is under investigation. The proposed mechanism involves the abnormal expression and activity of MMP‐9 with subsequent connective tissue degradation taking place at a time that does not synchronise with other events of labour. The local physiological signal by amniochorion cells to induce MMP‐9 expression is not known, but bacterial products and/or the proinflammatory cytokines, IL‐1β and TNF‐α, as paracrine or autocrine signals may trigger these processes in pregnancies complicated with intra‐amniotic infection. These signalling pathways indicate complex cooperative and bidirectional communications between amnion and choriodecidua in response to bacterial products, which include intermembranous cytokine traffic and signalling between tissues. Products secreted in culture by amniochorion and choriodecidual leucocytes, obtained from women who delivered following normal labour in the absence of infection, condition a specific microenvironment that induces collagen degradation in fetal membranes. Further characterisation of the role of choriodecidual leucocytes in the control of extracellular matrix degradation in amniochorion is currently under way.

Outdoor Air Pollution, Preterm Birth, and Low Birth Weight: Analysis of the World Health Organization Global Survey on Maternal and Perinatal Health

Background: Inhaling fine particles (particulate matter with diameter ≤ 2.5 μm; PM2.5) can induce oxidative stress and inflammation, and may contribute to onset of preterm labor and other adverse perinatal outcomes. Objectives: We examined whether outdoor PM2.5 was associated with adverse birth outcomes among 22 countries in the World Health Organization Global Survey on Maternal and Perinatal Health from 2004 through 2008. Methods: Long-term average (2001–2006) estimates of outdoor PM2.5 were assigned to 50-km–radius circular buffers around each health clinic where births occurred. We used generalized estimating equations to determine associations between clinic-level PM2.5 levels and preterm birth and low birth weight at the individual level, adjusting for seasonality and potential confounders at individual, clinic, and country levels. Country-specific associations were also investigated. Results: Across all countries, adjusting for seasonality, PM2.5 was not associated with preterm birth, but was associated with low birth weight [odds ratio (OR) = 1.22; 95% CI: 1.07, 1.39 for fourth quartile of PM2.5 (> 20.2 μg/m3) compared with the first quartile (< 6.3 μg/m3)]. In China, the country with the largest PM2.5 range, preterm birth and low birth weight both were associated with the highest quartile of PM2.5 only, which suggests a possible threshold effect (OR = 2.54; CI: 1.42, 4.55 and OR = 1.99; CI: 1.06, 3.72 for preterm birth and low birth weight, respectively, for PM2.5 ≥ 36.5 μg/m3 compared with PM2.5 < 12.5 μg/m3). Conclusions: Outdoor PM2.5 concentrations were associated with low birth weight but not preterm birth. In rapidly developing countries, such as China, the highest levels of air pollution may be of concern for both outcomes. Citation: Fleischer NL, Merialdi M, van Donkelaar A, Vadillo-Ortega F, Martin RV, Betran AP, Souza JP, O´Neill MS. 2014. Outdoor air pollution, preterm birth, and low birth weight: analysis of the World Health Organization Global Survey on Maternal and Perinatal Health. Environ Health Perspect 122:425–430; http://dx.doi.org/10.1289/ehp.1306837

Secretions of Interleukin-1β and Tumor Necrosis Factor α by Whole Fetal Membranes Depend on Initial Interactions of Amnion or Choriodecidua with Lipopolysaccharides or Group B Streptococci

Abstract The present study evaluated the secretions of interleukin (IL)-1β and tumor necrosis factor (TNF) α by fetal membranes stimulated with group B streptococci (GBS) and lipopolysaccharide (LPS). The aim was to evaluate the initial response of full-thickness membranes to the microbial insult using an in vitro experimental model that allowed testing of the individual contributions of amnion and choriodecidua to stimulation. Full-thickness membranes were obtained after delivery by elective cesarean section from women at 37–40 wk of gestation without evidence of active labor. The membranes were mounted in Transwell devices, physically separating the upper and lower chambers. The LPS (500 ng/ml) or GBS (1 × 106 colony-forming units/ml) was added to either the amniotic or choriodecidual surface, and accumulation of IL-1β and TNFα were measured in both compartments using a specific ELISA. Fetal membranes followed different patterns of secretion of proinflammatory cytokines that depended on the side to which the stimulus was added or the nature of the stimulus itself. The TNFα was secreted by amnion and choriodecidua in the presence of LPS or GBS, and stimulation with GBS induced a greater synthesis of IL-1β than did stimulation with LPS. Choriodecidual tissue was more responsive than amniotic tissue, and this response tended to be higher even when the stimulation was only on the amniotic side. However, the amnion plays an active role in recognizing LPS or GBS, contributing a significant amount of TNFα. Thus, cooperative and bidirectional communications occur between amnion and choriodecidua in response to bacterial products, which include intermembranous cytokine traffic and signaling between tissues.

Production of Matrix Metalloproteinase-9 in Lipopolysaccharide-Stimulated Human Amnion Occurs Through an Autocrine and Paracrine Proinflammatory Cytokine-Dependent System

Abstract The objective of this study was to determine the presence of autocrine/paracrine regulation of matrix metalloproteinase-9 (MMP-9) expression mediated by proinflammatory cytokines in human fetal membranes. Fetal membranes obtained from women who underwent cesarean delivery before labor were manually separated into amnion and chorion layers and maintained in culture. These explants were stimulated with tumor necrosis factor α (TNFα), interleukin-1β (IL-1β), and either lipopolysaccharide (LPS) alone or LPS with anti-TNFα or anti-IL-1β-neutralizing antibodies. Levels of proMMP-9 in culture media were evaluated by zymography. Enzyme-linked immunosorbant assay was performed to measure the quantity of IL-1β, TNFα, and tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) after LPS stimulation. ProMMP-9 activity was upregulated after stimulation of the amnion by LPS, TNFα, and IL-1β. The increased activity of proMMP-9 resulting from LPS stimulation in the amnion was blocked by the addition of TNFα neutralizing antibody but not with anti-IL-1β. No significant effect of LPS, TNFα, or IL-1β on proMMP-9 expression was observed in the chorion; however, the chorion produced both cytokines when stimulated with LPS. In contrast, TIMP-1 levels remained unchanged in all cultures incubated in the presence of LPS. Therefore, these data indicate that proMMP-9 is produced by the amnion but not the chorion in response to LPS. Because anti-TNFα-neutralizing antibody inhibits proMMP-9 activity in the amnion, TNFα appears to upregulate proMMP-9 production by the amnion in an autocrine fashion. Meanwhile, TNFα and IL-1β produced by the chorion may upregulate amnionic proMMP-9 production in a paracrine manner.

Progesterone induces human sperm Chemotaxis

OBJECTIVE To characterize the molecular nature of the chemotactic signal for sperm contained in human follicular fluid (FF). DESIGN Follicular fluid was fractionated and several procedures were followed to the physicochemical initial characterization of sperm chemotactic compound(s). MAIN OUTCOME MEASURE Relative chemotactic activity of each fraction was measured in a double chamber device. RESULTS Sperm chemotaxis was found to be associated with a lipid-like molecule extracted from FF. Several steroids were assayed individually and only P showed sperm chemotactic properties in dose-response curves. CONCLUSIONS In this paper we present experimental evidence to support the hypothesis that P, the main steroid component of FF, is a mediator of sperm chemoattraction in human beings.

Fetal membranes exhibit selective leukocyte chemotaxic activity during human labor

One of the characteristics of the labor process in women is leukocyte recruitment into reproductive tissues. These migrating cells may play a role in the induction of functional and biochemical changes associated with the rupture of fetal membranes during labor. This study was undertaken to assess whether human fetal membranes induce leukocyte chemotaxis during labor as well as to identify and characterize leukocyte chemoattractants secreted by these tissues. Leukocyte chemotactic activity of fetal membrane extracts obtained from women with full-term pregnancies and spontaneous active labor was compared with extracts from women without labor. The number and phenotype of attracted leukocytes were analyzed by flow cytometry. Chemokines were quantified using a Multiplex system and were identified by immunofluorescence histochemistry. Although all tested extracts induced chemotaxis of leukocytes, those prepared from women undergoing labor induced higher responses. Polymorphonuclear leukocyte chemotaxis increased approximately three-fold in response to extract from fetal membranes with labor. The same extracts elicited a significant increase in attracted monocytes (36-fold) as well as T and B lymphocytes, and NK cells (all five-fold) when compared to extracts from women without labor. This enhanced chemotactic activity was associated with the presence of IL-8, MCP-1, IP-10 and MIP-1alpha. We conclude that fetal membrane extracts obtained from women during labor exhibit selective chemotaxis for specific leukocyte subpopulations in vitro. This process may contribute to a microenvironment composed of specific leukocytes that promotes and amplifies biochemical changes in the fetal membranes during labor.

Evidence for a Role for the Adaptive Immune Response in Human Term Parturition

Spontaneous labor at term involves leukocyte recruitment and infiltration into the choriodecidua; yet, characterization of these leukocytes and their immunological mediators is incomplete. The purpose of this study was to characterize the immunophenotype of choriodecidual leukocytes as well as the expression of inflammatory mediators in human spontaneous parturition at term.

The Role of Chemokines in Term and Premature Rupture of the Fetal Membranes: A Review

Several studies indicate that at the choriodecidual interface, where maternal and fetal tissues make contact, a network of signals is established during labor that includes infiltration of leukocytes and secretion of pro-inflammatory cytokines. In this review, we provide an overview of the inflammatory milieu present in the choriodecidua during membrane rupture, describe the recruitment and homing of leukocytes to the reproductive tissues, and detail specific actions of the key chemokines released by the choriodecidual cells. These data lend further support to the hypothesis that labor is an inflammatory response, wherein the infiltrated leukocytes in the choriodecidua interface could be contributing to the creation of a microenvironment leading to collagenolysis, which would promote the rupture of these tissues during labor. In addition to the available information describing biological actions of chemokines during various pathological conditions such as infection, preterm labor and preterm rupture of membranes suggest that these compounds play important roles in other gestational events such as cervical dilation and myometrial contractions. Even though we do not know the totality of biochemical signals that integrate the molecular dialogue between leukocytes and the various gestational tissues, it is becoming increasingly evident that this microenvironment is characterized, at least in part, by the differential expression and secretion of chemokines that induce selective trafficking of leukocyte subsets to the fetal membranes. Therefore, chemokines should be considered as important regulatory molecules with the ability to initiate the events that characterize normal and pathological labor.