Platelet aggregation in normal pregnancy

Single-cell immune profiling of third trimester pregnancies defines importance of chemokine receptors and prevalence of CMV-induced NK cells in the periphery and decidua

Human pregnancy presents a unique physiological state that allows for growth of an antigenically dissimilar foetus and requires specific adaptations of the immune system. The immune system plays an important role in establishing and maintaining successful pregnancy, yet deep understanding of immunological responses in pregnancy is lacking. To provide in-depth understanding of the immunological landscape of pregnancy, with a focus on NK cells, we used high-throughput cell surface proteome screening of >350 markers and scRNAseq with 130 CITE-seq antibodies to identify key differentially expressed molecules and investigated their potential roles in altered immunity. We identified skewing in NK cell subsets towards higher frequencies of CD56bright cells caused by a reduced number of CD56dim cells in the peripheral blood during pregnancy and provide evidence for a role of chemokine receptor, CX3CR1, in NK cell activation. In addition, we defined a new cytomegalovirus (CMV)-induced decidual NK cell population in CMV+ pregnancies with tissue-residency markers. Overall, our data provide fundamental knowledge into how NK cell immunity is altered in pregnancy, and key knowledge needed to inform vaccine and therapeutic strategies to manage infections or pregnancy complications.

The Association Between the Maternal Pre-pregnancy Platelet Count and Fecundability in Mainland China: A Population-based Cohort Study

BACKGROUND

Currently, awareness about platelet count (PC) and its consequences for perinatal outcome have increased, but there is little reliable evidence on fecundability.

METHODS

Based on the National Free Pre-conception Check-up Projects supported by the Chinese government, 5,524,886 couples met the inclusion criteria and were included in this cohort study. Cox regression models were adopted to estimate fecundability ratios (FRs) and their 95% confidence intervals (CIs) for pre-pregnancy PC quintiles. Restricted cubic splines were used to flexibly model and visualize the relationship of PC with FRs. Microsoft SQL server and R software were used for data management and analysis.

RESULTS

The median of pre-pregnancy PC among women was 221.00 × 109/L. The first (<177.00 × 109/L) and second quintile (177.00-207.99 × 109/L) of PC showed slightly increased fecundability (Q1: adjusted FR 1.05; 95% CI, 1.04-1.06; Q2: adjusted FR 1.04; 95% CI, 1.03-1.05), while higher quintals (Q4: 236.00-271.99 × 109/L; Q5: ≥272.00 × 109/L) were related to reduction of fecundability, when compared with the third quintile of PC (208.00-235.99 × 109/L) (Q4: adjusted FR 0.96; 95% CI, 0.95-0.97; Q5: adjusted FR 0.88; 95% CI, 0.87-0.89). In the first quintiles (<177.00 × 109/L), only 20.93% women had PC below 129.94 × 109/L. An inverse-U-shaped association was consistently observed among women such that the lower PC within the normal range (<118.03 × 109/L) and higher PC (>223.06 × 109/L) were associated with the risk of reduced female fecundability (P for non-linearity < 0.01).

CONCLUSION

PC is associated with female fecundability. Further classification of PC levels may deepen our understanding of the early warnings and significance of female fecundability.

The extent of postpartum cardiac reverse remodeling is reflected in urine proteome

The association of postpartum cardiac reverse remodeling (RR) with urinary proteome, particularly in pregnant women with cardiovascular (CV) risk factors who show long-term increased risk of cardiovascular disease and mortality is unknown. We aim to profile the urinary proteome in pregnant women with/without CV risk factors to identify proteins associated with postpartum RR. Our study included a prospective cohort of 32 healthy and 27 obese and/or hypertensive and/or diabetic pregnant women who underwent transthoracic echocardiography, pulse-wave-velocity, and urine collection at the 3rd trimester and 6 months postpartum. Shotgun HPLC-MS/MS profiled proteins. Generalized linear mixed-effects models were used to identify associations between urinary proteins and left ventricle mass (LVM), a surrogate of RR. An increase in arterial stiffness was documented from 3rd trimester to 6 months after delivery, being significantly elevated in women with CV risk factors. In addition, the presence of at least one CV risk factor was associated with worse LVM RR. We identified 6 and 11 proteins associated with high and low LVM regression, respectively. These proteins were functionally linked with insulin-like growth factor (IGF) transport and uptake regulation by IGF binding-proteins, platelet activation, signaling and aggregation and the immune system's activity. The concentration of IGF-1 in urine samples was associated with low LVM regression after delivery. Urinary proteome showed a predicting potential for identifying pregnant women with incomplete postpartum RR.

Pregnancy as a susceptible state for thrombotic microangiopathies

Pregnancy and the postpartum period represent phases of heightened vulnerability to thrombotic microangiopathies (TMAs), as evidenced by distinct patterns of pregnancy-specific TMAs (e.g., preeclampsia, HELLP syndrome), as well as a higher incidence of nonspecific TMAs, such as thrombotic thrombocytopenic purpura or hemolytic uremic syndrome, during pregnancy. Significant strides have been taken in understanding the underlying mechanisms of these disorders in the past 40 years. This progress has involved the identification of pivotal factors contributing to TMAs, such as the complement system, ADAMTS13, and the soluble VEGF receptor Flt1. Regardless of the specific causal factor (which is not generally unique in relation to the usual multifactorial origin of TMAs), the endothelial cell stands as a central player in the pathophysiology of TMAs. Pregnancy has a major impact on the physiology of the endothelium. Besides to the development of placenta and its vascular consequences, pregnancy modifies the characteristics of the women's microvascular endothelium and tends to render it more prone to thrombosis. This review aims to delineate the distinct features of pregnancy-related TMAs and explore the contributing mechanisms that lead to this increased susceptibility, particularly influenced by the "gravid endothelium." Furthermore, we will discuss the potential contribution of histopathological studies in facilitating the etiological diagnosis of pregnancy-related TMAs.

Hemostasis in Pre-Eclamptic Women and Their Offspring: Current Knowledge and Hemostasis Assessment with Viscoelastic Tests

Pre-eclampsia (PE) is a placenta-mediated disease and remains a major cause of maternal and neonatal mortality and morbidity. As PE develops, normal pregnancy's hypercoagulable balance is disrupted, leading to platelet hyperactivation, excessive pathological hypercoagulability, and perturbed fibrinolysis. This narrative review aims to summarize the current knowledge regarding hemostasis in PE compared with healthy gestation and the potential effects of maternal PE on neonatal hemostasis. Finally, it aims to discuss hemostasis assessments for normal pregnancies and PE, emphasizing the role of viscoelastic tests, namely, thromboelastography (TEG) and thromboelastometry (ROTEM), for monitoring PE-associated hemostatic alterations. The use of TEG/ROTEM for assessing the hemostatic profile of PE women has been little considered, even though conventional coagulation tests (CCTs) have not helped to monitor hemostasis in this population. Compared with normal pregnancy, TEG/ROTEM in PE reveals an excessive hypercoagulability analogous with the severity of the disease, characterized by higher-stability fibrin clots. The TEG/ROTEM parameters can reflect PE severity and may be used for monitoring and as predictive markers for the disease.