Procoagulant extracellular vesicles in amniotic fluid

Extracellular vesicles from II trimester human amniotic fluid as paracrine conveyors counteracting oxidative stress

BACKGROUND

We previously demonstrated that the human amniotic fluid (hAF) from II trimester of gestation is a feasible source of stromal progenitors (human amniotic fluid stem cells, hAFSC), with significant paracrine potential for regenerative medicine. Extracellular vesicles (EVs) separated and concentrated from hAFSC secretome can deliver pro-survival, proliferative, anti-fibrotic and cardioprotective effects in preclinical models of skeletal and cardiac muscle injury. While hAFSC-EVs isolation can be significantly influenced by in vitro cell culture, here we profiled EVs directly concentrated from hAF as an alternative option and investigated their paracrine potential against oxidative stress.

METHODS

II trimester hAF samples were obtained as leftover material from prenatal diagnostic amniocentesis following written informed consent. EVs were separated by size exclusion chromatography and concentrated by ultracentrifugation. hAF-EVs were assessed by nanoparticle tracking analysis, transmission electron microscopy, Western Blot, and flow cytometry; their metabolic activity was evaluated by oximetric and luminometric analyses and their cargo profiled by proteomics and RNA sequencing. hAF-EV paracrine potential was tested in preclinical in vitro models of oxidative stress and dysfunction on murine C2C12 cells and on 3D human cardiac microtissue.

RESULTS

Our protocol resulted in a yield of 6.31 ± 0.98 × 109 EVs particles per hAF milliliter showing round cup-shaped morphology and 209.63 ± 6.10 nm average size, with relevant expression of CD81, CD63 and CD9 tetraspanin markers. hAF-EVs were enriched in CD133/1, CD326, CD24, CD29, and SSEA4 and able to produce ATP by oxygen consumption. While oxidative stress significantly reduced C2C12 survival, hAF-EV priming resulted in significant rescue of cell viability, with notable recovery of ATP synthesis and concomitant reduction of cell damage and lipid peroxidation activity. 3D human cardiac microtissues treated with hAF-EVs and experiencing H2O2 stress and TGFβ stimulation showed improved survival with a remarkable decrease in the onset of fibrosis.

CONCLUSIONS

Our results suggest that leftover samples of II trimester human amniotic fluid can represent a feasible source of EVs to counteract oxidative damage on target cells, thus offering a novel candidate therapeutic option to counteract skeletal and cardiac muscle injury.

The novel insights of epithelial-derived exosomes in various fibrotic diseases

The characteristics of fibrosis include the abnormal accumulation of extracellular matrix proteins and abnormal tissue repair caused by injury, infection, and inflammation, leading to a significant increase in organ failure and mortality. Effective and precise treatments are urgently needed to halt and reverse the progression of fibrotic diseases. Exosomes are tiny vesicles derived from endosomes, spanning from 40 to 160 nanometers in diameter, which are expelled into the extracellular matrix environment by various cell types. They play a crucial role in facilitating cell-to-cell communication by transporting a variety of cargoes, including proteins, RNA, and DNA. Epithelial cells serve as the primary barrier against diverse external stimuli that precipitate fibrotic diseases. Numerous research suggests that exosomes from epithelial cells have a significant impact on several fibrotic diseases. An in-depth comprehension of the cellular and molecular mechanisms of epithelial cell-derived exosomes in fibrosis holds promise for advancing the exploration of novel diagnostic biomarkers and clinical drug targets. In this review, we expand upon the pathogenic mechanisms of epithelium-derived exosomes and highlight their role in the fibrotic process by inducing inflammation and activating fibroblasts. In addition, we are particularly interested in the bioactive molecules carried by epithelial-derived exosomes and their potential value in the diagnosis and treatment of fibrosis and delineate the clinical utility of exosomes as an emerging therapeutic modality, highlighting their potential application in addressing various medical conditions.

Immersed in a reservoir of potential: amniotic fluid-derived extracellular vesicles

This review aims to encapsulate the current knowledge in extracellular vesicles extracted from amniotic fluid and amniotic fluid derived stem/stromal cells. Amniotic fluid (AF) bathes the developing fetus, providing nutrients and protection from biological and mechanical dangers. In addition to containing a myriad of proteins, immunoglobulins and growth factors, AF is a rich source of extracellular vesicles (EVs). These vesicles originate from cells in the fetoplacental unit. They are biological messengers carrying an active cargo enveloped within the lipid bilayer. EVs in reproduction are known to play key roles in all stages of pregnancy, starting from fertilisation through to parturition. The intriguing biology of AF-derived EVs (AF-EVs) in pregnancy and their untapped potential as biomarkers is currently gaining attention. EV studies in numerous animal and human disease models have raised expectations of their utility as therapeutics. Amniotic fluid stem cell and mesenchymal stromal cell-derived EVs (AFSC-EVs) provide an established supply of laboratory-made EVs. This cell-free mode of therapy is popular as an alternative to stem cell therapy, revealing similar, if not better therapeutic outcomes. Research has demonstrated the successful application of AF-EVs and AFSC-EVs in therapy, harnessing their anti-inflammatory, angiogenic and regenerative properties. This review provides an overview of such studies and discusses concerns in this emerging field of research.

IFPA Joan Hunt Senior Award in Placentology lecture: Extracellular vesicle signalling and pregnancy

The field of extracellular vesicle (EV) signalling has the potential to transform our understanding of maternal-fetal communication and affords new opportunities for non-invasive prenatal testing and therapeutic intervention. EVs have been implicated in implantation, placentation, maternal adaptation to pregnancy and complications of pregnancy, being detectable in maternal circulation as early as 6 weeks of pregnancy. EVs of differing biogenic origin, composition and bioactivity are released by cells to maintain homoeostasis. Induction of EV signalling is associated with aberrant cellular metabolism and manifests as changes in EV concentrations and/or composition. Characterizing such changes affords opportunity to develop more informative diagnostics and efficacious interventions. To develop accurate and reliable EV-based diagnostics requires: identification of disease-associated biomarkers in specific EV subpopulations; and rapid, reproducible and scalable sample processing. Conventional isolation methods face challenges due to co-isolation of particles with similar physicochemical properties. Methods targeting specific vesicle-surface epitopes and compatible with automated platforms show promise. Effective EV therapeutics require precise targeting, achieved through genetic engineering to release EVs expressing cell-targeting ligands and carrying therapeutic payloads. Unlike cell-based therapies, this approach offers advantages including: low immunogenicity; stability; and long-term storage. Although EV diagnostics and therapeutics in reproductive biology are nascent, available technologies can enhance our understanding of EV signalling between mother and fetus, its role in pregnancies and improve outcomes.

Extracellular vesicles as markers and mediators of pregnancy complications: gestational diabetes, pre-eclampsia, preterm birth and fetal growth restriction

In high income countries, approximately 10% of pregnancies are complicated by pre-eclampsia (PE), preterm birth (PTB), fetal growth restriction (FGR) and/or macrosomia resulting from gestational diabetes (GDM). Despite the burden of disease this places on pregnant people and their newborns, there are still few, if any, effective ways of preventing or treating these conditions. There are also gaps in our understanding of the underlying pathophysiologies and our ability to predict which mothers will be affected. The placenta plays a crucial role in pregnancy, and alterations in placental structure and function have been implicated in all of these conditions. As extracellular vesicles (EVs) have emerged as important molecules in cell-to-cell communication in health and disease, recent research involving maternal- and placental-derived EV has demonstrated their potential as predictive and diagnostic biomarkers of obstetric disorders.  This review will consider how placental and maternal EVs have been investigated in pregnancies complicated by PE, PTB, FGR and GDM and aims to highlight areas where further research is required to enhance the management and eventual treatment of these pathologies.

The biological functions of maternal-derived extracellular vesicles during pregnancy and lactation and its impact on offspring health

During pregnancy and lactation, mothers provide not only nutrients, but also many bioactive components for their offspring through placenta and breast milk, which are essential for offspring development. Extracellular vesicles (EVs) are nanovesicles containing a variety of biologically active molecules and participate in the intercellular communication. In the past decade, an increasing number of studies have reported that maternal-derived EVs play a crucial role in offspring growth, development, and immune system establishment. Hereby, we summarized the characteristics of EVs; biological functions of maternal-derived EVs during pregnancy, including implantation, decidualization, placentation, embryo development and birth of offspring; biological function of breast milk-derived EVs (BMEs) on infant oral and intestinal diseases, immune system, neurodevelopment, and metabolism. In summary, emerging studies have revealed that maternal-derived EVs play a pivotal role in offspring health. As such, maternal-derived EVs may be used as promising biomarkers in offspring disease diagnosis and treatment. However, existing research on maternal-derived EVs and offspring health is largely limited to animal and cellular studies. Evidence from human studies is needed.

Feto-placental Unit: From Development to Function

The placenta is an intriguing organ that allows us to survive intrauterine life. This essential organ connects both mother and fetus and plays a crucial role in maternal and fetal well-being. This chapter presents an overview of the morphological and functional aspects of human placental development. First, we describe early human placental development and the characterization of the cell types found in the human placenta. Second, the human placenta from the second trimester to the term of gestation is reviewed, focusing on the morphology and specific pathologies that affect the placenta. Finally, we focus on the placenta's primary functions, such as oxygen and nutrient transport, and their importance for placental development.

The Effect of Extracellular Vesicles on Thrombosis

The risk of cardiovascular events caused by acute thrombosis is high, including acute myocardial infarction, acute stroke, acute pulmonary embolism, and deep vein thrombosis. In this review, we summarize the roles of extracellular vesicles of different cellular origins in various cardiovascular events associated with acute thrombosis, as described in the current literature, to facilitate the future development of a precise therapy for thrombosis caused by such vesicles. We hope that our review will indicate a new horizon in the field of cardiovascular research with regard to the treatment of acute thrombosis, especially targeting thrombosis caused by extracellular vesicles secreted by individual cells. As more emerging technologies are being developed, new diagnostic and therapeutic strategies related to EVs are expected to be identified for related diseases in the future.

Extracellular vesicles from amniotic fluid, milk, saliva, and urine expose complexes of tissue factor and activated factor VII

BACKGROUND

Tissue factor (TF) is expressed in the adventitia of the vessel wall and on extracellular vesicles (EVs) in body fluids. TF and activated coagulation factor (F) VII(a) together form the so-called extrinsic tenase complex, which initiates coagulation.

AIM

We investigated whether EVs in amniotic fluid, milk, saliva, and urine expose functional extrinsic tenase complexes that can trigger coagulation.

METHODS

Milk, saliva, and urine were collected from healthy breastfeeding women (n = 6), and amniotic fluid was collected from healthy women undergoing routine amniocentesis (n = 7). EVs were isolated from body fluids by size exclusion chromatography (SEC) and clotting experiments were performed in the presence and absence of antibodies against TF and FVIIa in normal plasma and in FVII-deficient plasma. The ability of body fluids to generate FXa also was determined.

RESULTS

Amniotic fluid, milk, saliva, and urine triggered clotting of normal plasma and of FVII-deficient plasma, which was almost completely inhibited by an anti-FVII antibody and to a lesser extent by an anti-TF antibody. Fractionation of body fluids by SEC showed that only the fractions containing EVs triggered clotting in normal plasma and FVII-deficient plasma and generated FXa, which again was almost completely inhibited by an anti-FVII antibody and partially by an anti-TF antibody.

CONCLUSION

Here we show that EVs from amniotic fluid, milk, saliva, and urine expose complexes of TF and FVIIa (i.e., extrinsic tenase complexes) that directly activate FX. Based on our present findings we propose that these EVs from normal body fluids provide hemostatic protection.

A description of the coagulopathy characteristics in amniotic fluid embolism: a case report

Amniotic fluid embolism is frequently associated with coagulopathy. However, the exact nature and evolution of the bleeding disorder is incompletely understood. We report a case of clinically diagnosed amniotic fluid embolism associated with major haemorrhage and coagulopathy. We measured sequential levels of all individual clotting factors, thrombin generation, fibrinogen, and D-dimer levels over the course of the event, beginning shortly after the patient's initial collapse and during the subsequent resuscitation, to identify the specific abnormalities of coagulation from stored blood samples. A better understanding of amniotic fluid embolism and the associated coagulopathy is an important area of research to inform targeted treatment of the coagulopathy and improve outcomes for patients.

Procoagulant Activity in Amniotic Fluid Is Associated with Fetal-Derived Extracellular Vesicles

Procoagulant activity in amniotic fluid (AF) is positively correlated with phosphatidylserine (PS) and tissue factor (TF)-expressing(+) extracellular vesicles (EVs). However, it is unknown if pathological fetal conditions may affect the composition, phenotype, and procoagulant potency of EVs in AF. We sought to evaluate EV-dependent procoagulant activity in AF from pregnant people with fetuses with or without diagnosed chromosomal mutations. AF samples were collected by transabdominal amniocentesis and assessed for common karyotype defects (total n = 11, 7 healthy and 4 abnormal karyotypes). The procoagulant activity of AF was tested using a fibrin generation assay with normal pooled plasma and plasmas deficient in factors XII, XI, IX, X, V, and VII. EV number and phenotype were determined by flow cytometry with anti-CD24 and anti-TF antibodies. We report that factor-VII-, X-, or V-deficient plasmas did not form fibrin clots in the presence of AF. Clotting time was significantly attenuated in AF samples with chromosomal mutations. In addition, CD24+, TF+, and CD24+ TF+ EV counts were significantly lower in this group. Finally, we found a significant correlation between EV counts and the clotting time induced by AF. In conclusion, we show that AF samples with chromosomal mutations had fewer fetal-derived CD24-bearing and TF-bearing EVs, which resulted in diminished procoagulant potency. This suggests that fetal-derived EVs are the predominant source of procoagulant activity in AF.

The role of extracellular vesicles in animal reproduction and diseases

Extracellular vesicles (EVs) are nanosized membrane-enclosed compartments that serve as messengers in cell-to-cell communication, both in normal physiology and in pathological conditions. EVs can transfer functional proteins and genetic information to alter the phenotype and function of recipient cells, which undergo different changes that positively affect their structural and functional integrity. Biological fluids are enriched with several subpopulations of EVs, including exosomes, microvesicles (MVs), and apoptotic bodies carrying several cargoes, such as lipids, proteins, and nucleic acids. EVs associated with the reproductive system are actively involved in the regulation of different physiological events, including gamete maturation, fertilization, and embryo and fetal development. EVs can influence follicle development, oocyte maturation, embryo production, and endometrial-conceptus communication. EVs loaded with cargoes are used to diagnose various diseases, including pregnancy disorders; however, these are dependent on the type of cell of origin and pathological characteristics. EV-derived microRNAs (miRNAs) and proteins in the placenta regulate inflammatory responses and trophoblast invasion through intercellular delivery in the placental microenvironment. This review presents evidence regarding the types of extracellular vesicles, and general aspects of isolation, purification, and characterization of EVs, particularly from various types of embryos. Further, we discuss EVs as mediators and messengers in reproductive biology, the effects of EVs on placentation and pregnancy disorders, the role of EVs in animal reproduction, in the male reproductive system, and mother and embryo cross-communication. In addition, we emphasize the role of microRNAs in embryo implantation and the role of EVs in reproductive and therapeutic medicine. Finally, we discuss the future perspectives of EVs in reproductive biology.

Single-particle analysis of tear fluid reveals abundant presence of tissue factor-exposing extracellular vesicles with strong coagulation activity

Extracellular vesicles (EVs) in easily accessible body fluids have emerged as a promising source for liquid biopsy. Although tear collection is fast, safe, and noninvasive, EVs of tear fluid are less studied and their involvement in physiological and pathological processes is largely unknown. The aim of present study was to analyze and characterize EVs in tear fluid at the single-particle level to reveal the population heterogeneity. A laboratory-built nano-flow cytometer (nFCM) was used to analyze the purity, size distribution, and particle concentration of EVs isolated from unstimulated tears (basal tears) upon double ultracentrifugation (17 min at 100,000×g, 4 °C) via side scattering detection. The expression of CD9, CD63, CD81, CD47, CD45, CD24, and EpCAM was assessed via immunofluorescent detection. The EV concentration in tear fluid was measured to be 1.1 ± 0.7 × 10¹¹ particles/mL, which is approximately 100-fold higher than that of plasma EVs. In particular, it was identified for the first time that tears have strong coagulant activity owing to the abundant presence of tissue factor (TF) on tear EVs. The concentration of TF-exposing EVs (4.4 ± 3.1 × 10¹⁰ particles/mL) was found to be approximately 100-fold higher than their counterparts in saliva (4.5 ± 2.1 × 10⁸ particles/mL). We postulate that TF-exposing vesicles in tears might play a role in host defense by promoting clot formation and thus reducing the risk of pathogen invasion. The coagulant activity of tears triggered by TF-exposing EVs could provide a new research perspective for ophthalmic research.

Extracellular Vesicles in Human Milk

Milk supports the growth and development of infants. An increasing number of mostly recent studies have demonstrated that milk contains a hitherto undescribed component called extracellular vesicles (EVs). This presents questions regarding why milk contains EVs and what their function is. Recently, we showed that EVs in human milk expose tissue factor, the protein that triggers coagulation or blood clotting, and that milk-derived EVs promote coagulation. Because bovine milk, which also contains EVs, completely lacks this coagulant activity, important differences are present in the biological functions of human milk-derived EVs between species. In this review, we will summarize the current knowledge regarding the presence and biochemical composition of milk EVs, their function(s) and potential clinical applications such as in probiotics, and the unique problems that milk EVs encounter in vivo, including survival of the gastrointestinal conditions encountered in the newborn. The main focus of this review will be human milk-derived EVs, but when available, we will also include information regarding non-human milk for comparison.

Intraperitoneal Activation of Coagulation and Fibrinolysis in Patients with Cirrhosis and Ascites

Development of ascites is the most common form of decompensation of cirrhosis. We aimed to investigate the coagulation system in ascitic fluid and plasma of patients with cirrhosis. We determined coagulation parameters and performed clotting and fibrinolysis experiments in ascitic fluid and plasma of thoroughly characterized patients with cirrhosis and ascites ( n  = 25) and in plasma of patients with cirrhosis but without ascites ( n  = 25), matched for severity of portal hypertension. We also investigated plasma D-dimer levels in an independent cohort of patients ( n  = 317) with clinically significant portal hypertension (HVPG ≥ 10 mmHg), grouped according to ascites severity. Ascitic fluid was procoagulant in a clotting assay. The procoagulant potential of ascitic fluid was abolished by depletion of extracellular vesicles from ascitic fluid by filtration or by addition of a tissue factor-neutralizing antibody. Compared with plasma, extracellular vesicle-associated tissue factor activity was high in ascitic fluid, while activities of other coagulation factors were low. The extracellular vesicle-depleted fraction of ascitic fluid induced fibrinolysis, which was prevented by aprotinin, indicating the presence of plasmin in ascitic fluid. Plasma peak thrombin generation and parameters reflecting fibrinolysis were independently associated with the presence of ascites. Finally, plasma D-dimer levels were independently linked to ascites severity in our second cohort comprising 317 patients. In conclusion, coagulation and fibrinolysis become activated in ascites of patients with cirrhosis. While tissue factor-exposing extracellular vesicles in ascitic fluid seem unable to pass the peritoneal membrane, fibrinolytic enzymes get activated in ascitic fluid and may re-enter the systemic circulation and induce systemic fibrinolysis.

Human milk triggers coagulation via tissue factor-exposing extracellular vesicles

Almost a century ago, it was discovered that human milk activates the coagulation system, but the milk component that triggers coagulation had until now been unidentified. In the present study, we identify this component and demonstrate that extracellular vesicles (EVs) present in normal human milk expose coagulant tissue factor (TF). This coagulant activity withstands digestive conditions, mimicking those of breastfed infants, but is sensitive to pasteurization of pooled donor milk, which is routinely used in neonatal intensive care units. In contrast to human milk, bovine milk, the basis of most infant formulas, lacks coagulant activity. Currently, the physiological function of TF-exposing vesicles in human milk is unknown, but we speculate that these vesicles may be protective for infants. Another explanation could be nipple skin damage, which occurs in most breastfeeding women. Milk-derived TF-exposing EVs may seal the wound and thereby reduce bleeding and breast inflammation.

Effect of myeloperoxidase on the anticoagulant activity of low molecular weight heparin and rivaroxaban in an in vitro tumor model

BACKGROUND

Inflammation with leukocyte activation is a hallmark of cancer-associated thrombosis (CAT), and elevated leukocytes predict venous thromboembolism in cancer outpatients. In a recent trial, rivaroxaban was more efficacious than dalteparin in preventing CAT recurrence.

OBJECTIVES

In a proof-of-concept study, we aimed to provide a mechanistic basis for improved efficacy of rivaroxaban compared to low molecular weight heparin in CAT treatment.

METHODS

We studied the effects of rivaroxaban, dalteparin, and tinzaparin at peak and trough levels on tumor cell-induced procoagulant activity and platelet aggregation in the presence or absence of the cationic leukocyte-derived enzyme, myeloperoxidase (MPO). Furthermore, pro-inflammatory conditions were generated by stimulating whole blood with lipopolysaccharide (LPS) or phorbol-myristate-acetate (PMA), before measuring thrombin generation in plasma supernatants.

RESULTS

All three anticoagulants inhibited thrombin generation, fibrin clot formation, and platelet aggregation induced by the tissue factor-expressing prostate carcinoma cell line, 22Rv1. Pre-incubation with MPO partially attenuated the anticoagulant activity of dalteparin and tinzaparin, but not rivaroxaban, at trough levels. The effect of MPO did not involve the enzyme's catalytic properties, but required its structural integrity, as indicated by heat denaturation. In plasma obtained from LPS- or PMA-stimulated whole blood, elevated MPO antigen levels inversely correlated with the ability of tinzaparin to inhibit 22Rv1-induced thrombin generation.

CONCLUSIONS

Myeloperoxidase release may partially attenuate the anticoagulant activity of trough levels of dalteparin and tinzaparin in the context of paraneoplastic leukocyte activation. However, this effect is likely not sufficient to explain the improved efficacy of rivaroxaban, and possibly other oral factor Xa inhibitors, in CAT treatment.

Compartmentalized profiling of amniotic fluid cytokines in women with preterm labor

Objective

Amniotic fluid cytokines have been implicated in the mechanisms of preterm labor and birth. Cytokines can be packaged within or on the surface of extracellular vesicles. The main aim of this study was to test whether the protein abundance internal to and on the surface of extracellular vesicles changes in the presence of sterile intra-amniotic inflammation and proven intra-amniotic infection in women with preterm labor as compared to the women with preterm labor without either intra-amniotic inflammation or proven intra-amniotic infection.

Study design

Women who had an episode of preterm labor and underwent an amniocentesis for the diagnosis of intra-amniotic infection or intra-amniotic inflammation were classified into three groups: 1) preterm labor without either intra-amniotic inflammation or proven intra-amniotic infection, 2) preterm labor with sterile intra-amniotic inflammation, and 3) preterm labor with intra-amniotic infection. The concentrations of 38 proteins were determined on the extracellular vesicle surface, within the vesicles, and in the soluble fraction of amniotic fluid.

Results

1) Intra-amniotic inflammation, regardless of detected microbes, was associated with an increased abundance of amniotic fluid cytokines on the extracellular vesicle surface, within vesicles, and in the soluble fraction. These changes were most prominent in women with proven intra-amniotic infection. 2) Cytokine changes on the surface of extracellular vesicles were correlated with those determined in the soluble fraction; yet the magnitude of the increase was significantly different between these compartments. 3) The performance of prediction models of early preterm delivery based on measurements on the extracellular vesicle surface was equivalent to those based on the soluble fraction.

Conclusions

Differential packaging of amniotic fluid cytokines in extracellular vesicles during preterm labor with sterile intra-amniotic inflammation or proven intra-amniotic infection is reported herein for the first time. The current study provides insights into the biology of the intra-amniotic fluid ad may aid in the development of biomarkers for obstetrical disease.

The role of extracellular vesicles from different origin in the microenvironment of head and neck cancers

The proliferation and metastasis ability of tumors are mediate by the "mutual dialogue" between cells in the tumor microenvironment (TME). Extracellular vesicles (EVs), mainly exosomes and microvesicles, play an important role in achieving intercellular substance transport and information transfer in the TME. Initially considered "garbage dumpsters" and later referred to as "signal boxes", EVs carry "cargo" (proteins, lipids, or nucleic acids) that can redirect the function of a recipient cell. Currently, the molecular mechanisms and clinical applications of EVs in head and neck cancers (HNCs) are still at an early stage and need to be further investigate. In this review, we provide insight into the TME of HNCs, classifying and summarizing EVs derived from different cell types and illuminating their complex signaling networks involved in mediating tumor proliferation, invasion and metastasis, vascular angiogenesis and cancer drug resistance. In addition, we highlight the application of EVs in HNCs, underlining the special pathological and physiological environment of HNCs. The application of tumor heterogeneous EVs in saliva and circulating blood diagnostics will provide a new perspective for the early screening, real-time monitoring and prognostic risk assessment of HNCs. Given the concept of precise and individual therapy, nanostructured EVs are equipped with superior characteristics of biocompatibility, low immunogenicity, loadability and modification ability, making these molecules one of the new strategies for HNCs treatment.

Amniotic fluid as a potent activator of blood coagulation and platelet aggregation: Study with rotational thromboelastometry

INTRODUCTION

Pulmonary thromboembolism (PTE) is a leading cause of maternal death and frequently occurs during early puerperium. Amniotic fluid components are frequently observed in the maternal circulation in parturition; however, it currently remains unclear whether amniotic fluid contamination in maternal blood is related to the high incidence of PTE in early postpartum.

OBJECTIVES

To examine the influence of amniotic fluid on blood coagulation and fibrinolysis systems with thromboelastometry.

MATERIALS AND METHODS

Twenty-one pregnant women were recruited. We used whole citrated blood in ROTEM® (Tem Innovations GmbH, Munich, Germany), including the non-activated assay (NATEM), assessments for extrinsic (EXTEM) and intrinsic pathways (INTEM), fibrin polymerization (FIBTEM), and hyperfibrinolysis (APTEM), with amniotic fluid contamination, and measured the clotting time (CT), clot formation time (CFT), alpha, amplitude at 10 min (A10), maximum clot firmness (MCF), and lysis indices at 30 min (LI30) and 60 min (LI60).

RESULTS

Short CT in all assays as well as short CFT, high alpha, and increased A10 and MCF in NATEM were observed with amniotic fluid contamination. A10 and MCF as well as LI30 and LI60 decreased in EXTEM. Decreased LI60 with the mixture of amniotic fluid was not improved by tranexamic acid in APTEM.

CONCLUSIONS

Amniotic fluid accelerated thrombin production and activated platelet aggregation without inducing hyperfibrinolysis in whole blood. The activated tissue factor pathway with amniotic fluid produced soft and fragile clots due to its influence on platelets, which may be associated with, at least partly, the high incidence of PTE in early puerperium, particularly after cesarean section.

Salivary tissue factor induces thrombin generation in a diurnal rhythm

BACKGROUND

Upon tooth extraction, extravascular tissue factor (TF) initiates coagulation to arrest bleeding. Additionally, saliva is in constant contact with the wound and contains extracellular vesicle-derived procoagulant TF. Since the duration of postextraction bleeding is highly variable between patients, we hypothesized this may be caused by variation in saliva-derived TF-induced clotting activity.

OBJECTIVES

We aimed to assess the variability of saliva-induced thrombin generation (TG) in healthy individuals.

METHODS

TG was performed according to the calibrated automated thrombinography (CAT) method. Diluted saliva was added (instead of recombinant TF and phospholipids [PL]) to normal pooled plasma (NPP) in the absence/presence of anti-TF antibodies. Saliva was collected from healthy individuals in the morning, afternoon and evening.

RESULTS

Addition of saliva to NPP induced TG curves similar to those induced by r-TF and PL. Moreover, addition of anti-TF antibodies abolished saliva-induced TG, indicating TF-dependence. A large inter-individual variability (peak CV 31%, range 73-220 nmol/L thrombin) in saliva-induced TG was observed. Interestingly, within subjects, saliva-induced TG was significantly (P = 0.009) increased in the morning (167 ± 40 nmol/L thrombin) compared to the afternoon (124 ± 39 nmol/L thrombin) and evening (123 ± 38 nmol/L thrombin). This diurnal variation was not attributable to gingival stimulation or damage induced by tooth brushing.

CONCLUSIONS

We identified a diurnal rhythm in salivary TF activity that may have implications for tooth extraction and dental surgery, as performing invasive procedures in the morning may be beneficial for rapid coagulation. Future studies should correlate salivary TF to clinical outcome (ie, postextraction bleeding) and assess a possible relation with bacterial status in the oral cavity.

Impact of fetal maceration grade on risk of maternal disseminated intravascular coagulation after intrauterine fetal death - A retrospective cohort study

Disseminated intravascular coagulation (DIC) is a life-threatening event that is the endpoint of a pathologically activated cascade leading to excessive consumption of platelets culminating in bleeding. Several diseases are known to be associated with DIC, some of which may also occur during pregnancy or the puerperium. One of the potential risk factors that have been considered as a potential trigger for DIC is the retention of a highly macerated fetus after intrauterine fetal death (IUFD). However, sparse evidence exists on its clinical implication on hemostasis parameters. In this retrospective single-center study, we investigated the role of fetal maceration grades 0-III on the risk of DIC in 91 women following IUFD between gestational weeks (+days) 22 + 0 and 41 + 6 between 2003 and 2017. We calculated the Erez DIC-score after consideration of maternal platelet count (PC), prothrombin time (PT) and fibrinogen (Fib) and correlated the findings with fetal maceration grade. Mean (±SD) age of women was 32.1 ± 6.7 years. Neither maternal hemostasis parameters (PC, PT, Fib), nor the Erez score showed a statistically significant difference between maceration grades 0-III with median values of 1 for all four grades (maceration grade I: range 0 to 27; I: 0 to 51; II: 0 to 52; III: 0 to 39). We therefore conclude, that the pathophysiology of DIC in women after singleton IUFD is unrelated to the degree of fetal maceration.

Extracellular Vesicles in Human Reproduction in Health and Disease

Extensive evidence suggests that the release of membrane-enclosed compartments, more commonly known as extracellular vesicles (EVs), is a potent newly identified mechanism of cell-to-cell communication both in normal physiology and in pathological conditions. This review presents evidence about the formation and release of different EVs, their definitive markers and cargo content in reproductive physiological processes, and their capacity to convey information between cells through the transfer of functional protein and genetic information to alter phenotype and function of recipient cells associated with reproductive biology. In the male reproductive tract, epididymosomes and prostasomes participate in regulating sperm motility activation, capacitation, and acrosome reaction. In the female reproductive tract, follicular fluid, oviduct/tube, and uterine cavity EVs are considered as vehicles to carry information during oocyte maturation, fertilization, and embryo-maternal crosstalk. EVs via their cargo might be also involved in the triggering, maintenance, and progression of reproductive- and obstetric-related pathologies such as endometriosis, polycystic ovarian syndrome, preeclampsia, gestational diabetes, and erectile dysfunction. In this review, we provide current knowledge on the present and future use of EVs not only as biomarkers, but also as therapeutic targeting agents, mainly as vectors for drug or compound delivery into target cells and tissues.