A comprehensive summary of the ASEV-CzeSEV joint meeting on extracellular vesicles.

This report summarizes the ASEV-CzeSEV Joint Meeting on Extracellular Vesicles (EVs), held at the Medical University of Vienna in September 2024. The conference focused on introducing and expanding EV research and infrastructure within the Czech Republic and Austria, highlighting areas for collaboration. Key sessions featured research on EV-based diagnostics, tissue regeneration, interspecies communication and therapeutic applications, with an emphasis on shared resources and cross-border partnerships.

Altered thrombin generation with prothrombin complex concentrate is not detected by viscoelastic testing: an in vitro study.

Background: Bleeding guidelines currently recommend use of viscoelastic testing (VET) to direct haemostatic resuscitation in severe haemorrhage. However, VET-derived parameters of clot initiation, such as clotting time (CT) and activated clotting time (ACT), might not adequately reflect a clinically relevant interaction of procoagulant and anticoagulant activity, as revealed by thrombin generation assays. The aim of this study was to evaluate the ability of CT and ACT to indicate thrombin generation activity.

Enhancing human ACE2 expression in mouse models to improve COVID-19 research.

Mice are one of the most common biological models for laboratory use. However, wild-type mice are not susceptible to COVID-19 infection due to the low affinity of mouse ACE2, the entry protein for SARS-CoV-2. Although mice with human ACE2 (hACE2) driven by Ace2 promoter reflect its tissue specificity, these animals exhibit low ACE2 expression, potentially limiting their fidelity in mimicking COVID-19 manifestations and their utility in viral studies.

Platelet-derived extracellular vesicles induced through different activation pathways drive melanoma progression by functional and transcriptional changes.

Background: Beyond their conventional roles in hemostasis and wound healing, platelets have been shown to facilitate hematogenous metastasis by interacting with cancer cells. Depending on the activation route, platelets also generate different platelet-derived extracellular vesicles (PEVs) that may educate cancer cells in the circulation or within the tumor microenvironment. We engaged different platelet-activating receptors, including glycoprotein VI and C-type lectin-like receptor 2, to generate a spectrum of PEV types.

Male Down syndrome Ts65Dn mice have impaired bone regeneration.

Trisomy of human chromosome 21 (Ts21) individuals present with a spectrum of low bone mineral density (BMD) that predisposes this vulnerable group to skeletal injuries. To determine the bone regenerative capacity of Down syndrome (DS) mice, male and female Dp16 and Ts65Dn DS mice underwent amputation of the digit tip (the terminal phalanx (P3)). This is a well-established mammalian model of bone regeneration that restores the amputated skeletal segment and all associated soft tissues.

Differential microRNA expression patterns between TallyHo/JngJ mice and non-diabetic Swiss Webster Random/Jackson mice.

Type 2 diabetes mellitus (T2DM) increases the susceptibility of bone fragility. The underlying mechanisms have, however, remained largely unknown. MicroRNAs (miRNAs) are short single-stranded non-coding RNA molecules with utility as biomarkers due to their easy accessibility and stability in bodily fluids.

Artificial Plateletoids Recruit Blood Proteins to Shield Symbiotic Thrombin: a Silk Fibroin/Calcium Interface Medicated Thrombin Generation and Preservation.

Breaking the constraints of thrombin during storage and in vivo applications remains challenging because of its low stability and sensitivity to environmental temperature and acidity. Herein, an artificial plateletoid is developed for in situ thrombin generation through a co-incubation approach with plasma in vitro, utilizing a silk fibroin/Ca interface, to enhance the activity and stability of the generated thrombin. Notably, the enzymatic activity of the plateletoid thrombin platform is as high as 30 U g, leading to rapid clotting within 55 s, and it persisted for at least 90 days at as high as 37 °C.

Prolonged cultivation enhances the stimulatory activity of hiPSC mesenchymal progenitor-derived conditioned medium.

Background: Human induced pluripotent stem cells represent a scalable source of youthful tissue progenitors and secretomes for regenerative therapies. The aim of our study was to investigate the potential of conditioned medium (CM) from hiPSC-mesenchymal progenitors (hiPSC-MPs) to stimulate osteogenic differentiation of human bone marrow-derived mesenchymal stromal cells (MSCs). We also investigated whether prolonged cultivation or osteogenic pre-differentiation of hiPSC-MPs could enhance the stimulatory activity of CM.

Cyclosporin A toxicity on endothelial cells differentiated from induced pluripotent stem cells: Assembling an adverse outcome pathway.

Cyclosporin A (CSA) is a potent immunosuppressive agent in pharmacologic studies. However, there is evidence for side effects, specifically regarding vascular dysfunction. Its mode of action inducing endothelial cell toxicity is partially unclear, and a connection with an adverse outcome pathway (AOP) is not established yet.

Lethal versus surviving sepsis phenotypes displayed a partly differential regional expression of neurotransmitters and inflammation and did not modify the blood-brain barrier permeability in female CLP mice.

Background: Septic encephalopathy is frequent but its pathophysiology is enigmatic. We studied expression of neurotransmitters, inflammation and integrity of the blood-brain barrier (BBB) in several brain regions during abdominal sepsis. We compared mice with either lethal or surviving phenotype in the first 4 sepsis days.

Effect of Unfractionated Heparin Dose on Complement Activation and Selected Extracellular Vesicle Populations during Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation (ECMO) provides critical support for patients with severe cardiopulmonary dysfunction. Unfractionated heparin (UFH) is used for anticoagulation to maintain circuit patency and avoid thrombotic complications, but it increases the risk of bleeding. Extracellular vesicles (EVs), nano-sized subcellular spheres with potential pro-coagulant properties, are released during cellular stress and may serve as potential targets for monitoring anticoagulation, particularly in thromboinflammation.

Reduced circulating CD63 extracellular vesicle levels associate with atherosclerosis in hypercholesterolaemic mice and humans.

Aims: The association and co-isolation of low-density lipoproteins (LDL) and extracellular vesicles (EVs) have been shown in blood plasma. Here we explore this relationship to better understand the role of EVs in atherogenesis.

Methods And Results: Wild type (WT), PCSK9, and LDLR C57BL/6 mice were used in this study.

Artificial intelligence in traumatology.

Aims: The aim of this study was to create artificial intelligence (AI) software with the purpose of providing a second opinion to physicians to support distal radius fracture (DRF) detection, and to compare the accuracy of fracture detection of physicians with and without software support.

Methods: The dataset consisted of 26,121 anonymized anterior-posterior (AP) and lateral standard view radiographs of the wrist, with and without DRF. The convolutional neural network (CNN) model was trained to detect the presence of a DRF by comparing the radiographs containing a fracture to the inconspicuous ones.

Snorkel-tag based affinity chromatography for recombinant extracellular vesicle purification.

Extracellular vesicles (EVs) are lipid nanoparticles and play an important role in cell-cell communications, making them potential therapeutic agents and allowing to engineer for targeted drug delivery. The expanding applications of EVs in next generation medicine is still limited by existing tools for scaling standardized EV production, single EV tracing and analytics, and thus provide only a snapshot of tissue-specific EV cargo information. Here, we present the Snorkel-tag, for which we have genetically fused the EV surface marker protein CD81, to a series of tags with an additional transmembrane domain to be displayed on the EV surface, resembling a snorkel.

VISION - an open-source software for automated multi-dimensional image analysis of cellular biophysics.

Environment-sensitive probes are frequently used in spectral and multi-channel microscopy to study alterations in cell homeostasis. However, the few open-source packages available for processing of spectral images are limited in scope. Here, we present VISION, a stand-alone software based on Python for spectral analysis with improved applicability.

Comparison of two viscoelastic testing devices in a porcine model of surgery, hemorrhage and resuscitation.

Introduction: Viscoelastic hemostatic assays (VHA) are integral in contemporary hemostatic resuscitation, offering insights into clot formation, firmness, and lysis for rapid diagnosis and targeted therapy. Large animal models, particularly swine, provide anatomical and physiological analogies for coagulation research. Despite the growing use of VHAs, the ClotPro device's applicability in porcine models remains unexplored.

Drug delivery under cover of erythrocytes extends drug half-life: A thrombolytic targeting therapy utilizing microenvironment-responsive artificial polysaccharide microvesicles.

The development of thrombolytic drug carriers capable of thrombus-targeting, prolonged circulation time, intelligent responsive release, and the ability to inhibit thrombotic recurrences remains a promising but significant challenge. To tackle this, an artificial polysaccharide microvesicle drug delivery system (uPA-CS/HS@RGD-ODE) was constructed. It is composed of cationic chitosan and anionic heparin assembled in a layer by layer structure, followed by surface modification using RGD peptide and 2-(N-oxide-N,N-diethylamino) ethylmethacrylate (ODE) before encapsulation of urokinase-type plasminogen activator (uPA).

Isolation and characterization of bone mesenchymal cell small extracellular vesicles using a novel mouse model.

Extracellular vesicles (EVs) are key mediators of cell-cell communication and are involved in transferring specific biomolecular cargo to recipient cells to regulate their physiological functions. A major challenge in the understanding of EV function in vivo is the difficulty ascertaining the origin of the EV particles. The recent development of the "Snorkel-tag," which includes EV-membrane-targeted CD81 fused to a series of extra-vesicular protein tags, can be used to mark EVs originating from a specific source for subsequent isolation and characterization.

Unveiling the human fetal-maternal interface during the first trimester: biophysical knowledge and gaps.

The intricate interplay between the developing placenta and fetal-maternal interactions is critical for pregnancy outcomes. Despite advancements, gaps persist in understanding biomechanics, transport processes, and blood circulation parameters, all of which are crucial for safe pregnancies. Moreover, the complexity of fetal-maternal interactions led to conflicting data and methodological variations.