BackgroundExosomes are one of the several types of cell-derived vesicles with a diameter of 30–100 nm. These extracellular vesicles are recognized as potential markers of human diseases such as cancer. However, their use in diagnostic tests requires an objective and high-throughput method to define their phenotype and determine their concentration in biological fluids. To identify circulating as well as cell culture-derived vesicles, the current standard is immunoblotting or a flow cytometrical analysis for specific proteins, both of which requires large amounts of purified vesicles.MethodsBased on the technology of protein microarray, we hereby present a highly sensitive Extracellular Vesicle (EV) Array capable of detecting and phenotyping exosomes and other extracellular vesicles from unpurified starting material in a high-throughput manner. To only detect the exosomes captured on the EV Array, a cocktail of antibodies against the tetraspanins CD9, CD63 and CD81 was used. These antibodies were selected to ensure that all exosomes captured are detected, and concomitantly excluding the detection of other types of microvesicles.ResultsThe limit of detection (LOD) was determined on exosomes derived from the colon cancer cell line LS180. It clarified that supernatant from only approximately 104 cells was needed to obtain signals or that only 2.5×104 exosomes were required for each microarray spot (~1 nL). Phenotyping was performed on plasma (1–10 µL) from 7 healthy donors, which were applied to the EV Array with a panel of antibodies against 21 different cellular surface antigens and cancer antigens. For each donor, there was considerable heterogeneity in the expression levels of individual markers. The protein profiles of the exosomes (defined as positive for CD9, CD63 and CD81) revealed that only the expression level of CD9 and CD81 was approximately equal in the 7 donors. This implies questioning the use of CD63 as a standard exosomal marker since the expression level of this tetraspanin was considerably lower.

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BackgroundUnderstanding the pathogenic role of extracellular vesicles (EVs) in disease and their potential diagnostic and therapeutic utility is extremely reliant on in-depth quantification, measurement and identification of EV sub-populations. Quantification of EVs has presented several challenges, predominantly due to the small size of vesicles such as exosomes and the availability of various technologies to measure nanosized particles, each technology having its own limitations.Materials and MethodsA standardized methodology to measure the concentration of extracellular vesicles (EVs) has been developed and tested. The method is based on measuring the EV concentration as a function of a defined size range. Blood plasma EVs are isolated and purified using size exclusion columns (qEV) and consecutively measured with tunable resistive pulse sensing (TRPS). Six independent research groups measured liposome and EV samples with the aim to evaluate the developed methodology. Each group measured identical samples using up to 5 nanopores with 3 repeat measurements per pore. Descriptive statistics and unsupervised multivariate data analysis with principal component analysis (PCA) were used to evaluate reproducibility across the groups and to explore and visualise possible patterns and outliers in EV and liposome data sets.ResultsPCA revealed good reproducibility within and between laboratories, with few minor outlying samples. Measured mean liposome (not filtered with qEV) and EV (filtered with qEV) concentrations had coefficients of variance of 23.9% and 52.5%, respectively. The increased variance of the EV concentration measurements could be attributed to the use of qEVs and the polydisperse nature of EVs.ConclusionThe results of this study demonstrate the feasibility of this standardized methodology to facilitate comparable and reproducible EV concentration measurements.

We describe the first Danish case of presumed inflammatory and thrombotic response to vaccination with an adenoviral (ChAdOx1) vector‐based COVID‐19 vaccine (AZD1222). The case describes a 60‐year‐old woman who was admitted with intractable abdominal pain 7 days after receiving the vaccine. Computed tomography of the abdomen revealed bilateral adrenal hemorrhages. On the following day, she developed a massive right‐sided ischemic stroke and magnetic resonance imaging angiography showed occlusion of the right internal carotid artery. The ischemic area was deemed too large to offer reperfusion therapy. During admission, blood tests showed a remarkable drop in platelet counts from 118,000 to 5000 per μl and a substantial increase in D‐dimer. The patient died on the sixth day of hospitalization. Blood tests revealed platelet factor 4 reactive antibodies, imitating what is seen in heparin‐induced thrombocytopenia. This may be a novel immune‐mediated response to the vaccine.

Background-Obesity, measured as body mass index, is associated with venous thromboembolism (VTE). Body mass index is a marker of excess weight and correlates well with body fat content in adults; however, it fails to consider the distribution of body fat. We assessed the association between anthropometric variables and VTE. Methods and Results-From 1993 to 1997, 27 178 men and 29 876 women 50 to 64 years of age were recruited into a Danish prospective study (Diet, Cancer, and Health). During 10 years of follow-up, the outcome of VTE events was identified in the Danish National Patient Registry and verified by review of medical records. Body weight, body mass index, waist circumference, hip circumference, and total body fat were measured at baseline. We used Cox proportional hazard models to assess the association between anthropometry and VTE. Age was used as a time axis, with further adjustment for smoking, physical activity, height, hypertension, diabetes mellitus, cholesterol, and, among women, use of hormone replacement therapy. We verified 641 incident VTE events and found monotonic dose-response relationships between VTE and all anthropometric measurements in both sexes. In mutually adjusted analyses of waist and hip circumference, we found that hip circumference was positively associated with VTE in women but not in men, whereas waist circumference was positively associated with VTE in men but not in women. Conclusions-All measurements of obesity are predictors of the risk for VTE. Positive associations were found between VTE and body weight, body mass index, waist circumference, hip circumference, and total body fat mass. (Circulation.

Summary. Background: Large-scale prospective studies are needed to assess whether smoking is associated with venous thromboembolism (VTE) (i.e. deep venous thrombosis and pulmonary embolism) independently of established risk factors. Objective: To investigate the association between smoking and the risk of VTE among middle-aged men and women. Methods: From 1993 to 1997, 27 178 men and 29 875 women, aged 50-64 years and born in Denmark, were recruited into the Danish prospective study ÔDiet, Cancer and HealthÕ. During follow-up, VTE cases were identified in the Danish National Patient Registry. Medical records were reviewed and only verified VTE cases were included in the study. Baseline data on smoking and potential confounders were included in gender stratified Cox proportional hazard models to asses the association between smoking and the risk of VTE. The analyses were adjusted for alcohol intake, body mass index, physical activity, and in women also for use of hormone replacement therapy. Results: During follow-up, 641 incident cases of VTE were verified. We found a positive association between current smoking and VTE, with a hazard ratio of 1.52 (95% CI, 1.15-2.00) for smoking women and 1.32 (95% CI, 1.00-1.74) for smoking men, and a positive dose-response relationship. Former smokers had the same hazard as never smokers. Conclusions: Smoking was an independent risk factor for VTE among middle-aged men and women. Former smokers have the same risk of VTE as never smokers, indicating acute effects of smoking, and underscoring the potential benefits of smoking cessation.

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