Low Molecular Weight Heparins (LMWH) and Implications along Pregnancy: a Focus on the Placenta

Single-cell transcriptome analyses reveal disturbed decidual homoeostasis in obstetric antiphospholipid syndrome

OBJECTIVES

Obstetric antiphospholipid syndrome (OAPS) is an autoimmune disease characterised by the presence of antiphospholipid antibodies in circulation and pathological pregnancy. However, the pathogenesis of OAPS remains unknown. We aimed to reveal cellular compositions and molecular features of decidual cells involved in the development of OAPS using single-cell RNA sequencing (scRNA-seq).

METHODS

We performed unbiased scRNA-seq analysis on the first-trimester decidua from five OAPS patients and five healthy controls (HCs), followed by validations with flow cytometry, immunohistochemical staining and immunofluorescence in a larger cohort. Serum chemokines and cytokines were measured by using ELISA.

RESULTS

A higher ratio of macrophages but a lower ratio of decidual natural killer (dNK) cells was found in decidua from OAPS compared with HCs. Vascular endothelial cells shrinked in OAPS decidua while having upregulated chemokine expression and conspicuous responses to IFN-γ and TNF-α. Macrophages in OAPS had stronger phagocytosis function, complement activation signals and relied more on glycolysis. dNK cells were more activated in OAPS and had enhanced cytotoxicity and IFN-γ production. Downregulation of granules in OAPS dNK cells could be associated with suppressed glycolysis. Moreover, stromal cells had a prosenescent state with weakened immune surveillance for senescent cells in OAPS. In addition, the cellular interactions between decidual immune cells and those of immune cells with non-immune cells under disease state were altered, especially through chemokines, IFN-γ and TNF-α.

CONCLUSION

This study provided a comprehensive decidual cell landscape and identified aberrant decidual microenvironment in OAPS, providing some potential therapeutic targets for this disease.

Platelet distribution width and the risk of unexplained recurrent pregnancy loss: a meta-analysis

OBJECTIVE

Changes of platelet distribution width (PDW) have been observed in women with unexplained recurrent pregnancy loss (URPL). However, relevant previous studies showed inconsistent results. We performed a meta-analysis to comprehensively evaluate the association between PDW and URPL.

METHODS

Observational studies reporting the difference of PDW between women with and without URPL were retrieved by searching PubMed, Embase, Web of Science, Wanfang, and CNKI. A random-effect model was used to pool the results by incorporating potential heterogeneity.

RESULTS

Eleven case-control studies with 1847 women with URPL and 2475 healthy women were included. Age was matched for all studies between cases and controls. Pooled results showed women with URPL had significantly increased level of PDW (mean difference [MD]: 1.54%, 95% CI: 1.04 to 2.03, p < 0.05; I2 =77%). Subgroup analysis showed consistent result for URPL defined as ≥ 2 (MD: 1.45%, p = 0.003) and ≥ 3 (MD: 1.61%, p < 0.001) failed clinical pregnancies, and in studies compared to women with normal pregnancy (MD: 2.02%, p < 0.001) and non-pregnant healthy women (MD: 1.34%, p < 0.001). Results of the meta-analysis also showed that increment of PDW was associated with higher odds of URPL (per 1 unit, odds ratio: 1.26, 95% CI: 1.17 to 1.35, p < 0.001; I2 = 0%).

CONCLUSIONS

Women with URPL had significantly increased levels of PDW compared to healthy women without URPL, which suggest that higher PDW may predict the risk of URPL.

Perturbations in kinetics of the thrombin generation assay identify women at risk of preeclampsia in the first trimester and provide the rationale for a preventive approach

BACKGROUND

Activation of the coagulation system and increased thrombin generation have been implicated in the pathophysiology of preeclampsia, and this rationale supports the administration of low-molecular-weight heparin to prevent this syndrome in patients at risk. Yet, randomized trials of this prophylactic measure have yielded contradictory results. A possible explanation is that only a subset of patients with preeclampsia have excessive thrombin generation and would benefit from the administration of low-molecular-weight heparin. Therefore, the key questions are whether and when patients who subsequently develop preeclampsia present evidence of abnormal thrombin generation.

OBJECTIVE

This study aimed to determine (1) the kinetics of thrombin generation throughout gestation in women with a normal pregnancy and in those with early and late preeclampsia, and (2) the diagnostic performance of in vivo thrombin generation parameters to predict the development of preeclampsia.

STUDY DESIGN

This retrospective, nested case-control study was based on a prospective longitudinal cohort of singleton gestations. Cases comprised women who developed preeclampsia (n=49), and controls consisted of patients with a normal pregnancy (n=45). Preeclampsia was classified into early-onset (n=24) and late-onset (n=25). Longitudinal changes in the parameters of the thrombin generation assay (lag time, time to peak thrombin concentration, peak thrombin concentration, endogenous thrombin generation, and velocity index) throughout gestation were compared between the study groups, and normal pregnancy percentiles were derived from the control group. We tested whether a single parameter or a combination of parameters, derived from the kinetics of thrombin generation, could identify patients who subsequently developed preeclampsia. Time-related parameters <10th percentile were considered short, and concentration-related parameters >90th percentile were considered high.

RESULTS

(1) Patients who developed preeclampsia (early- and late-onset) had abnormal thrombin generation kinetics as early as 8 to 16 weeks of pregnancy; (2) patients with a combination of a short lag time and high peak thrombin concentration at 8 to 16 weeks of pregnancy had an odds ratio of 43.87 for the subsequent development of preeclampsia (area under the curve, 0.79; sensitivity, 56.8%; specificity, 92.7%; positive likelihood ratio, 7.76); (3) at 16 to 22 weeks of gestation, patients with a combination of a short lag time and a high velocity index had an odds ratio of 16 for the subsequent development of preeclampsia (area under the curve, 0.78; sensitivity, 62.2%; specificity, 92.5%; positive likelihood ratio, 8.29).

CONCLUSION

During early pregnancy, the thrombin generation assay can identify the subset of patients at a greater risk for the development of preeclampsia owing to accelerated and enhanced production of thrombin. This observation provides a rationale for testing the efficacy of low-molecular-weight heparin in this subset of patients. We propose that future research on the efficacy of low-molecular-weight heparin and other interventions targeting the coagulation system to prevent preeclampsia should be focused on patients with abnormal kinetics of thrombin generation.

Co-administration of tacrolimus and low molecular weight heparin in patients with a history of implantation failure and elevated peripheral blood natural killer cell proportion

AIM

To investigate the therapeutic effect of co-administration of tacrolimus (TAC) and low-molecular-weight heparin (LMWH) or LMWH only on pregnancy outcomes in the female with a history of implantation failure and elevated peripheral blood natural killer (pNK) cell proportion in frozen-thawed embryo transfer cycles.

METHODS

To evaluate the pregnancy parameters for 249 patients with ≥2 implantation failures and pNK cell proportion ≥12% by analyzing a retrospective observational cohort study. Sixty patients had received the co-administration TAC and LMWH (TAC & LMWH group), 85 others had only taken LMWH (LWMH group), and the rest did not take any particular drugs (control group).

RESULTS

The experimental finding indicated that the TAC & LMWH group and the LMWH group showed higher clinical pregnancy rates than the control group (p < 0.05), and TAC & LMWH group had a much higher live birth rate. According to the binary logistic regression analysis, the combination of TAC and LMWH was conducive to clinical pregnancy and live birth rate and reduced the possibility of miscarriage. It would not affect the result of spontaneous abortion and live birth, although the LMWH was only beneficial to clinical pregnancy. In addition, these findings were similar for these three groups' obstetrical and neonatal outcomes.

CONCLUSIONS

The combination of TAC and LMWH can improve clinical pregnancy and live birth rates and reduce the risk of spontaneous miscarriage in patients with a history of implantation failure and elevated pNK ratio. LMWH is also beneficial to clinical pregnancy.

Undifferentiated Connective Tissue Disease in Pregnancy: A Topic Yet to be Explored

Undifferentiated connective tissue disease (UCTD) is characterized by signs and symptoms suggestive of a connective tissue disease (CTD), but not fulfilling criteria for a specific CTD. Although UCTD is probably the most common rheumatic disease diagnosed in pregnant women, data about disease course during pregnancy and perinatal outcomes are very limited. Compared to other CTDs, UCTD seems to have milder clinical manifestations in pregnancy. Its natural history is related to disease activity at conception. In fact, if the disease is in a state of remission or minimal activity at conception, pregnancy outcomes are generally good. On the contrary, patients who become pregnant in a moment of high disease activity and/or who have multiple antibodies positivity show an increased risk of disease flares, evolution to a definite CTD and obstetric complications, such as fetal growth restriction, preeclampsia and preterm birth. Therefore, a preconception assessment is essential in women with UCTD to evaluate maternal and fetal risks, to initiate interventions to optimize disease activity, and to adjust medications to those that are least harmful to the fetus. The aim of the present study was to review the available literature about pregnancy course, maternal and fetal outcomes and therapeutic approaches of pregnant women with UCTD.