Increased platelet activation in preterm labor

Role of Platelet Activating Factor as a Mediator of Inflammatory Diseases and Preterm Delivery

Nearly 70% of preterm deliveries occur spontaneously, and the clinical pathways involved include preterm labor and preterm premature rupture of membranes. Prediction of preterm delivery is considered crucial due to the significant effects of preterm birth on health and the economy at both the personal and community levels. Although similar inflammatory processes occur in both term and preterm delivery, the premature activation of these processes or exaggerated inflammatory response triggered by infection or sterile factors leads to preterm delivery. Platelet activating factor (PAF) is a phosphoglycerylether lipid mediator of inflammation that is implicated in infections, cancers, and various chronic diseases and disorders including cardiovascular, renal, cerebrovascular, and central nervous system diseases. In gestational tissues, PAF mediates the inflammatory pathways that stimulate the effector mechanisms of labor, including myometrial contraction, cervical dilation, and fetal membrane rupture. Women with preterm labor and preterm premature rupture of membranes have increased levels of PAF in their amniotic fluid. In mice, the intrauterine or intraperitoneal administration of carbamyl PAF activates inflammation in gestational tissues, thereby eliciting preterm delivery. This review summarizes recent research on PAF as an important inflammatory mediator in preterm delivery and in other inflammatory disorders, highlighting its potential value for prediction, intervention, and prevention of these diseases.

Plasma IGFBP-1, Fas, kallistatin, and P-selectin as predictive biomarkers of histologic chorioamnionitis and associated intra-amniotic infection in women with preterm labor

PROBLEM

To determine whether altered levels of 13 plasma biomarkers, alone or in combination, could be independently associated with histologic chorioamnionitis (HCA) and microbial-associated HCA (defined as the presence of HCA along with microbial invasion) in women with preterm labor (PTL).

METHODS OF STUDY

This was a retrospective cohort study involving 77 singleton pregnant women with PTL (23-34 gestational weeks) who delivered within 96 h of plasma and amniotic fluid (AF) sampling. DKK-3, E-selectin, Fas, haptoglobin, IGFBP-1, kallistatin, MMP-2, MMP-8, pentraxin 3, progranulin, P-selectin, SAA4, and TGFBI levels were assayed in plasma samples by ELISA. AF obtained via amniocentesis was used for microorganism identification.

RESULTS

Multiple logistic regression analyses revealed significant associations between low plasma IGFBP-1 levels and acute HCA, and between low plasma Fas and kallistatin levels, and elevated plasma P-selectin levels and microbial-associated HCA (all p < .05), after adjusting for gestational age. Using a stepwise regression procedure, a multi-biomarker panel for microbial-associated HCA was developed, which included plasma MMP-2, kallistatin, and P-selectin levels (area under the curve [AUC], .867). The AUC for this three-marker panel was significantly or borderline significantly greater than that of any single variable included in the panel. However, a predictive model for acute HCA could not be developed because only one variable (MMP-2) was selected.

CONCLUSIONS

These findings demonstrate that IGFBP-1, Fas, kallistatin, and P-selectin are associated with acute HCA and microbial-associated HCA in women with PTL. Their combined use can significantly improve the diagnostic ability for the detection of microbial-associated HCA.

The profiles of soluble adhesion molecules in the "great obstetrical syndromes". J Matern Fetal Neonatal Med 2018;32:2113-2136. [PMID: 29320948 DOI: 10.1080/14767058.2018.1427058]

OBJECTIVE

The objective of this study was to determine the profiles of maternal plasma soluble adhesion molecules in patients with preeclampsia, small-for-gestational-age (SGA) fetuses, acute pyelonephritis, preterm labor with intact membranes (PTL), preterm prelabor rupture of the membranes (preterm PROM), and fetal death.

MATERIALS AND METHODS

A cross-sectional study was conducted to determine maternal plasma concentrations of sE-selectin, sL-selectin, and sP-selectin as well as sICAM-1, sVCAM-1, and sPECAM-1 in patients with (1) an uncomplicated pregnancy (control, n = 100); (2) preeclampsia (n = 94); (3) SGA fetuses (in women without preeclampsia/hypertension, n = 45); (4) acute pyelonephritis (n = 25); (5) PTL (n = 53); (6) preterm PROM (n = 24); and (7) fetal death (n = 34). Concentrations of soluble adhesion molecules and inflammatory cytokines (tumor necrosis factor (TNF)-α and interleukin (IL)-8) were determined with sensitive and specific enzyme-linked immunoassays.

RESULTS

In comparison to women with a normal pregnancy, (1) women with preeclampsia had higher median concentrations of sE-selectin, sP-selectin, and sVCAM-1, and a lower concentration of sL-selectin (all p values < .001); (2) patients with SGA fetuses had higher median concentrations of sE-selectin, sP-selectin, and sVCAM-1 (all p values < .05); (3) patients with a fetal death had higher median concentrations of sE-selectin and sP-selectin (all p values < .05); (4) patients with acute pyelonephritis had higher median plasma concentrations of sE-selectin, sICAM-1, and sVCAM-1 (all p values < .001); (5) patients with preeclampsia and acute pyelonephritis, plasma concentrations of sVCAM-1, sE-selectin, and sP-selectin correlated with those of the proinflammatory cytokines TNF-α and interleukin (IL)-8 (all p values < .05); (6) patients with PTL had a higher median concentration of sP-selectin and a lower median concentration of VCAM-1 (all p values < .05); and (7) women with preterm PROM had lower median concentrations of sL-selectin and sVCAM-1 (all p values < .05).

CONCLUSIONS

The results of this study show that endothelial cell activation/dysfunction reflected by the plasma concentration of sE-selectin is not specific to preeclampsia but is present in pregnancies complicated by SGA fetuses, acute pyelonephritis, and fetal death. Collectively, we report that each obstetrical syndrome appears to have a stereotypical profile of soluble adhesion molecules in the peripheral circulation.

The Influence of Labor and Placental Separation on Hemostasis in Term Pregnancy

We studied the hemostatic effects in 68 term preg nant subjects with normal pregnancy (n = 39), gestational diabetes mellitus (n = 21), pregnancy-induced hypertension (n = 8), during labor, after placental separation, and at 24 hours postpartum. During labor, a hypercoagulable state with en hanced fibrinolysis and platelet activation along with elevated plasminogen activator inhibitor-1 and plasminogen activator inhibitor-2 were seen. In all cases following placental separa tion, enhanced fibrinolysis persisted with further elevated tissue plasminogen activator antigen and D-dimer levels, increased thrombin generation and platelet activation with decreasing plasminogen activator inhibitor-1 levels. By 24 hours postpar tum, thrombin generation (thrombin-antithrombin complex) decreased to a nonpregnant level except for pregnancy induced hypertension, but enhanced prothrombin activation (F1+2) was evident in normal, gestational diabetes mellitus and pregnancy- induced hypertension. Reduced total protein S and antithrom bin III activity with normal protein C and elevated fibrinogen levels seen during labor were not affected by delivery. How ever, although factor VII showed a decreasing trend at 24 hours postpartum it remained elevated above the normal nonpregnant level. At 24 hours postpartum, a hypercoagulable state still persisted in normal, gestational diabetes mellitus and preg nancy-induced hypertension term pregnancy accompanied by enhanced fibrinolysis and elevated plasminogen substrate for fibrinolysis, suggesting a critical dynamic equilibrium between a thrombotic and hemorrhagic state.

Premature labor: a state of platelet activation?

OBJECTIVE

This study was undertaken to determine whether premature labor is associated with changes in the maternal plasma concentration of soluble CD40 ligand (sCD40L), a marker of platelet activation.

METHODS

A cross-sectional study included patients in the following groups: 1) non-pregnant (n=21); 2) normal pregnancy (n=71); 3) normal pregnancy at term with (n=67) and without labor (n=88); 4) preterm labor (PTL) with intact membranes (n=136) that was divided into the following sub-groups: 4a) PTL who delivered at term (n=49); 4b) PTL without intra-amniotic infection and/or inflammation (IAI) who delivered preterm (n=54); and 4c) PTL with IAI who delivered preterm (n=33). sCD40L concentrations were measured by ELISA.

RESULTS

The median maternal plasma sCD40L concentration was higher in pregnant than non-pregnant women (P=0.017). Patients with PTL had a higher median maternal plasma sCD40L concentration than women with normal pregnancies, regardless of the presence or absence of IAI and gestational age at delivery (P<0.001 for all comparisons). IAI was not associated with a higher median maternal plasma concentration of sCD40L.

CONCLUSIONS

Normal pregnancy is a state in which there is a physiologic increase of sCD40L. PTL was associated with an increased median maternal plasma sCD40L concentration that could not be accounted for by IAI. Thus, our findings suggest that platelet activation occurs during an episode of preterm labor.

[Is a biological assessment necessary to realize an obstetrical epidural anaesthesia in a patient whose interrogation and clinical examination are strictly normal?]

In France, coagulation blood tests are usually ordered before performing an epidural anaesthesia. This French habit obeys to the fear of triggering an epidural haematoma induced by neuraxial anaesthesia. This analysis of literature shows that these practices do not protect anaesthesiologists against this clinical risk or its medico-legal consequences. As shown by epidemiological studies, epidural haematoma in pregnancy is associated to the occurrence of HELLP syndrome. On the opposite, gestational thrombocytopenia is not associated to any bleeding risk. According to the recommendations of the French Society of Anaesthesia (Sfar), only a clinical examination and an interrogatory must be done to diagnose coagulation defects before general or loco regional anaesthesia. Normal pregnancy is not an exception to this rule except for the platelet number which must be evaluated during the 3rd trimester of pregnancy. This platelet numeration might detect a rare idiopathic thrombopenic purpura. This recommendation is valid only for normal pregnancy. The clinician must ensure that pregnancy is still normal by seeking for symptoms of pregnancy-induced pathology such as preeclampsia or HELLP syndrome before setting an epidural anaesthesia. The possibly late occurrence of these complications during the per- or post-partum explain why a coagulation test performed even a few days before anaesthesia may not allow to detect any coagulation defect favouring the risk of epidural haematoma.