Plasma Extracellular Vesicles Research Articles

Circulating plasma-derived extracellular vesicles expressing bone and kidney markers are associated with neurocognitive impairment in people living with HIV

BackgroundAlthough effective antiretroviral therapy (ART) has improved the life expectancy of people with HIV (PWH), the prevalence of milder forms of HIV-associated neurocognitive disorders (HAND) persist, and it is associated with systemic and neuro-inflammatory processes that could impact other organ systems. However, the complex signaling mechanisms between the bone-kidney systems and the brain in HAND remain unknown. Extracellular vesicles (EVs) play a potential role in inter-organ communication and are involved in regulating cell activity in distant tissues. In this study, we examined whether levels of EVs from bone-and kidney-related cells associate with cognitive dysfunction and explored the relationship between kidney-bone EV axis in PWH experiencing cognitive deficits.MethodsEV subtypes were characterized in plasma from 61 PWH with either cognitive impairment (CI, n = 53) or normal cognition (NC, n = 8) based on the American Academy of Neurology criteria for HIV-associated dementia (HAD, n = 11), minor cognitive motor disorder (MCMD, n = 25) or asymptomatic neurocognitive impairment (ANI, n = 17) by spectral flow cytometry. EVs were profiled with markers reflecting bone and kidney cell origin. A support vector machine learning-based model was employed for analyses of EV phenotypes to predict the cognitive dysfunction.ResultsPlasma-EVs expressing osteocalcin, sclerostin, and nephrin were significantly higher in the cognitive impairment group compared to the normal cognition group. EVs bearing kidney cell markers correlated significantly with bone-derived EVs. A machine learning-based model, comprised of osteocalcin+, nephrin+, and CD24+ EVs predicted cognitive impairment in PWH on ART.ConclusionOur study reveals that neurocognitive impairment in PWH is associated with increased levels of plasma EVs enriched with the bone markers osteocalcin and sclerostin and the kidney marker nephrin, suggesting that these EV subtypes may be novel candidate biomarkers for disease-spanning neurocognitive dysfunction. Moreover, the relationship between bone-derived EVs with kidney-derived EVs may suggest their role in mediating inter-organ crosstalk in the pathogenesis of HIV-associated cognitive impairment.

Lipidomic Analysis of Plasma Extracellular Vesicles Derived from Alzheimer's Disease Patients.

Analysis of blood-based indicators of brain health could provide an understanding of early disease mechanisms and pinpoint possible intervention strategies. By examining lipid profiles in extracellular vesicles (EVs), secreted particles from all cells, including astrocytes and neurons, and circulating in clinical samples, important insights regarding the brain's composition can be gained. Herein, a targeted lipidomic analysis was carried out in EVs derived from plasma samples after removal of lipoproteins from individuals with Alzheimer's disease (AD) and healthy controls. Differences were observed for selected lipid species of glycerolipids (GLs), glycerophospholipids (GPLs), lysophospholipids (LPLs) and sphingolipids (SLs) across three distinct EV subpopulations (all-cell origin, derived by immunocapture of CD9, CD81 and CD63; neuronal origin, derived by immunocapture of L1CAM; and astrocytic origin, derived by immunocapture of GLAST). The findings provide new insights into the lipid composition of EVs isolated from plasma samples regarding specific lipid families (MG, DG, Cer, PA, PC, PE, PI, LPI, LPE, LPC), as well as differences between AD and control individuals. This study emphasizes the crucial role of plasma EV lipidomics analysis as a comprehensive approach for identifying biomarkers and biological targets in AD and related disorders, facilitating early diagnosis and potentially informing novel interventions.

Transferrin-conjugated magnetic nanoparticles for the isolation of brain-derived blood exosomal MicroRNAs: A novel approach for Parkinson's disease diagnosis

BackgroundBrain-derived exosomes circulate in the bloodstream and other bodily fluids, serving as potential indicators of neurological disease progression. These exosomes present a promising avenue for the early and precise diagnosis of neurodegenerative conditions. Notably, miRNAs found in plasma extracellular vesicles (EVs) offer distinct diagnostic benefits due to their stability, abundance, and resistance to breakdown. ResultsIn this study, we introduce a method using transferrin conjugated magnetic nanoparticles (TMNs) to isolate these exosomes from the plasma of patients with neurological disorders. This TMNs technique is both quick (<35 min) and cost-effective, requiring no high-priced ingredients or elaborate equipment for EV extraction. Our method successfully isolated EVs from 33 human plasma samples, including those from patients with Parkinson's disease (PD), Multiple Sclerosis (MS), and Dementia. Using quantitative polymerase chain reaction (PCR) analysis, we evaluated the potential of 8 exosomal miRNA profiles as biomarker candidates. Six exosomal miRNA biomarkers (miR-195-5p, miR-495-3p, miR-23b-3P, miR-30c-2-3p, miR-323a-3p, and miR-27a-3p) were consistently linked with all stages of PD. SignificanceThe TMNs method provides a practical, cost-efficient way to isolate EVs from biological samples, paving the way for non-invasive neurological diagnoses. Furthermore, the identified miRNA biomarkers in these exosomes may emerge as innovative tools for precise diagnosis in neurological disorders including PD.

Schwann cell-derived extracellular vesicles promote memory impairment associated with chronic neuropathic pain.

The pathogenesis of memory impairment, a common complication of chronic neuropathic pain (CNP), has not been fully elucidated. Schwann cell (SC)-derived extracellular vesicles (EVs) contribute to remote organ injury. Here, we showed that SC-EVs may mediate pathological communication between SCs and hippocampal neurons in the context of CNP. We used an adeno-associated virus harboring the SC-specific promoter Mpz and expressing the CD63-GFP gene to track SC-EVs transport. microRNA (miRNA) expression profiles of EVs and gain-of-function and loss-of-function regulatory experiments revealed that miR-142-5p was the main cargo of SC-EVs. Next, luciferase reporter gene and phenotyping experiments confirmed the direct targets of miR-142-5p. The contents and granule sizes of plasma EVs were significantly greater in rats with chronic sciatic nerve constriction injury (CCI)than in sham rats. Administration of the EV biogenesis inhibitor GW4869 ameliorated memory impairment in CCI rats and reversed CCI-associated dendritic spine damage. Notably, during CCI stress, SC-EVs could be transferred into the brain through the circulation and accumulate in the hippocampal CA1-CA3 regions. miR-142-5p was the main cargo wrapped in SC-EVs and mediated the development of CCI-associated memory impairment. Furthermore, α-actinin-4 (ACTN4), ELAV-like protein 4 (ELAVL4) and ubiquitin-specific peptidase 9 X-linked (USP9X) were demonstrated to be important downstream target genes for miR-142-5p-mediated regulation of dendritic spine damage in hippocampal neurons from CCI rats. Together, these findings suggest that SCs-EVs and/or their cargo miR-142-5p may be potential therapeutic targets for memory impairment associated with CNP.

Transcriptomic Analysis of Extracellular Vesicles in the Search for Novel Plasma and Thrombus Biomarkers of Ischemic Stroke Etiologies.

Accurate etiologic diagnosis provides an appropriate secondary prevention and better prognosis in ischemic stroke (IS) patients; still, 45% of IS are cryptogenic, urging us to enhance diagnostic precision. We have studied the transcriptomic content of plasma extracellular vesicles (EVs) (n = 21) to identify potential biomarkers of IS etiologies. The proteins encoded by the selected genes were measured in the sera of IS patients (n = 114) and in hypertensive patients with (n = 78) and without atrial fibrillation (AF) (n = 20). IGFBP-2, the most promising candidate, was studied using immunohistochemistry in the IS thrombi (n = 23) and atrium of AF patients (n = 13). In vitro, the IGFBP-2 blockade was analyzed using thromboelastometry and endothelial cell cultures. We identified 745 differentially expressed genes among EVs of cardioembolic, atherothrombotic, and ESUS groups. From these, IGFBP-2 (cutoff > 247.6 ng/mL) emerged as a potential circulating biomarker of embolic IS [OR = 8.70 (1.84-41.13) p = 0.003], which was increased in patients with AF vs. controls (p < 0.001) and was augmented in cardioembolic vs. atherothrombotic thrombi (p < 0.01). Ex vivo, the blockage of IGFBP-2 reduced clot firmness (p < 0.01) and lysis time (p < 0.001) and in vitro, diminished endothelial permeability (p < 0.05) and transmigration (p = 0.06). IGFBP-2 could be a biomarker of embolic IS and a new therapeutic target involved in clot formation and endothelial dysfunction.

Plasma and synovial fluid extracellular vesicles display altered microRNA profiles in horses with naturally occurring post-traumatic osteoarthritis: an exploratory study.

The objective of this study was to characterize extracellular vesicles (EVs) in plasma and synovial fluid obtained from horses with and without naturally occurring post-traumatic osteoarthritis (PTOA). EVs were isolated from plasma and synovial fluid from horses with (n = 6) and without (n = 6) PTOA. Plasma and synovial fluid EVs were characterized with respect to quantity, size, and surface markers. Small RNA sequencing was performed, and differentially expressed microRNAs (miRNAs) underwent bioinformatic analysis to identify putative targets and to explore potential associations with specific biological processes. Plasma and synovial fluid samples from horses with PTOA had a significantly higher proportion of exosomes and a lower proportion of microvesicles compared to horses without PTOA. Small RNA sequencing revealed several differentially expressed miRNAs, including miR-144, miR-219-3p, and miR-199a-3l in plasma and miR-199a-3p, miR-214, and miR-9094 in synovial fluid EVs. Bioinformatics analysis of the differentially expressed miRNAs highlighted their potential role in fibrosis, differentiation of chondrocytes, apoptosis, and inflammation pathways in PTOA. We have identified dynamic molecular changes in the small noncoding signatures of plasma and synovial fluid EVs in horses with naturally occurring PTOA. These findings could serve to identify promising biomarkers in the pathogenesis of PTOA, to facilitate the development of targeted therapies, and to aid in establishing appropriate translational models of PTOA.

Plasma extracellular vesicles in meningioma patients following radiotherapy as liquid biopsy- a prospective explorative biomarker study (ARO 2023-05/AG-NRO-07)

BackgroundWhile surgical resection remains the primary treatment approach for symptomatic or growing meningiomas, radiotherapy represents an auspicious alternative in patients with meningiomas not safely amenable to surgery. Biopsies are often omitted in light of potential postoperative neurological deficits, resulting in a lack of histological grading and (molecular) risk stratification. In this prospective explorative biomarker study, extracellular vesicles in the bloodstream will be investigated in patients with macroscopic meningiomas to identify a biomarker for molecular risk stratification and disease monitoring.MethodsIn total, 60 patients with meningiomas and an indication of radiotherapy (RT) and macroscopic tumor on the planning MRI will be enrolled. Blood samples will be obtained before the start, during, and after radiotherapy, as well as during clinical follow-up every 6 months. Extracellular vesicles will be isolated from the blood samples, quantified and correlated with the clinical treatment response or progression. Further, nanopore sequencing-based DNA methylation profiles of plasma EV-DNA will be generated for methylation-based meningioma classification.DiscussionThis study will explore the dynamic of plasma EVs in meningioma patients under/after radiotherapy, with the objective of identifying potential biomarkers of (early) tumor progression. DNA methylation profiling of plasma EVs in meningioma patients may enable molecular risk stratification, facilitating a molecularly-guided target volume delineation and adjusted dose prescription during RT treatment planning.

Extracellular vesicles and their effect on vascular haemodynamics: a systematic review.

Extracellular vesicles (EVs) are released from all cell types studied to date and act as intercellular communicators containing proteins, nucleic acids and lipid cargos. They have been shown to be involved in maintaining homoeostasis as well as playing a role in the development of pathology including hypertension and cardiovascular disease. It is estimated that there is 109-1010 circulating EVs/mL in the plasma of healthy individuals derived from various sources. While the effect of EVs on vascular haemodynamic parameters will be dependent on the details of the model studied, we systematically searched and summarized current literature to find patterns in how exogenously injected EVs affected vascular haemodynamics. Under homoeostatic conditions, evidence from wire and pressure myography data demonstrate that injecting isolated EVs derived from cell types found in blood and blood vessels resulted in the impairment of vasodilation in blood vessels ex vivo. Impaired vasodilation was also observed in rodents receiving intravenous injections of human plasma EVs from cardiovascular diseases including valvular heart disease, acute coronary syndrome, myocardial infarction and end stage renal disease. When EVs were derived from models of metabolic syndromes, such as diabetes, these EVs enhanced vasoconstriction responses in blood vessels ex vivo. There were fewer publications that assessed the effect of EVs in anaesthetised or conscious animals to confirm whether effects on the vasculature observed in ex vivo studies translated into alterations in vascular haemodynamics in vivo. In the available conscious animal studies, the in vivo data did not always align with the ex vivo data. This highlights the importance of in vivo work to determine the effects of EVs on the integrative vascular haemodynamics.

Prospective Study of Extracellular Vesicles in Plasma as Potential Biomarkers for Silent Brain Infarcts (P10-4.013)

Prospective Study of Extracellular Vesicles in Plasma as Potential Biomarkers for Silent Brain Infarcts (P10-4.013)

Extracellular Vesicles as Surrogates for the Regulation of the Drug Transporters ABCC2 (MRP2) and ABCG2 (BCRP).

Drug efflux transporters of the ATP-binding-cassette superfamily play a major role in the availability and concentration of drugs at their site of action. ABCC2 (MRP2) and ABCG2 (BCRP) are among the most important drug transporters that determine the pharmacokinetics of many drugs and whose overexpression is associated with cancer chemoresistance. ABCC2 and ABCG2 expression is frequently altered during treatment, thus influencing efficacy and toxicity. Currently, there are no routine approaches available to closely monitor transporter expression. Here, we developed and validated a UPLC-MS/MS method to quantify ABCC2 and ABCG2 in extracellular vesicles (EVs) from cell culture and plasma. In this way, an association between ABCC2 protein levels and transporter activity in HepG2 cells treated with rifampicin and hypericin and their derived EVs was observed. Although ABCG2 was detected in MCF7 cell-derived EVs, the transporter levels in the vesicles did not reflect the expression in the cells. An analysis of plasma EVs from healthy volunteers confirmed, for the first time at the protein level, the presence of both transporters in more than half of the samples. Our findings support the potential of analyzing ABC transporters, and especially ABCC2, in EVs to estimate the transporter expression in HepG2 cells.

Abstract LB099: Identifying actionable genomic alterations in non-small cell lung cancer through the analysis of extracellular vesicles in plasma

Abstract Lung cancer is the second most common cancer worldwide, accounting for 2.2 million new cases and 1.8 million deaths in 2020. Personalized targeted therapy based on actionable molecular markers has completely transformed the therapeutic landscape in NSCLC, which has improved considerably the overall survival. However, ~50% of NSCLC patients with tissue biopsy inaccessible or inadequate, limiting biomarker testing and access to targeted therapies. The availability of a wide range of highly effective targeted therapy options for NSCLC justifies the significance of developing non-invasive and cost-effective detection assays for guiding targeted therapy selection in NSCLC.Extracellular vesicles (EVs) are lipid-bilayer-enclosed vesicles of sub-micrometer size that are secreted by virtually all cell types. They contain hundreds of different proteins, thousands of intact RNA species, and double-stranded DNA (dsDNA) fragments that sample the entire human genome. Recent findings further corroborate the potential role of EVs in early cancer screening, cancer diagnosis, treatment selection and monitoring. In this study, we used lipid nanoprobe (LNP) for EV isolation from plasma and droplet digital PCR assay for detecting actionable genomic alternation to aid targeted therapy selection in NSCLC. Specifically, we extracted EV associated DNA/RNA from plasma first, and then we used the individual ddPCR assays for detecting KRAS mutations, EGFR mutations, and ALK fusions from isolated EVs associated nucleic acids, respectively. We identified KRAS mutations G12C/G12S/G13C/G12A/Q61H, EGFR L858R mutation and exon 19 deletion, and ALK-EML4 gene fusion variant 3 from 12 NSCLC patients that matched the mutation status obtained from patient tissue specimens. Only in 1 out 13 patients, EV mutation status did not match the mutation status from the tissue specimen. This data indicated that clinical actionable gene mutations are present in EVs associated nucleic acids isolated from plasma samples of NSCLC patients. We anticipate that this novel non-invasive EVs-based actionable genomic alterations detection test would efficiently assist physicians/oncologists in selecting optimal targeted therapies for cancer treatment, as recommended by National Comprehensive Cancer Network (NCCN) guidelines for NSCLC. Citation Format: Hongzhang He, Jadranka Milosevic, Siyang Zheng. Identifying actionable genomic alterations in non-small cell lung cancer through the analysis of extracellular vesicles in plasma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB099.

Circulating extracellular vesicles as biomarker for diagnosis, prognosis and monitoring in glioblastoma patients.

Extracellular vesicles (EVs) obtained by noninvasive liquid biopsy from patient blood can serve as biomarkers. Here, we investigated the potential of circulating plasma EVs to serve as an indicator in the diagnosis, prognosis and treatment response of glioblastoma patients. Plasma samples were collected from glioblastoma patients at multiple timepoints before and after surgery. EV concentrations were measured by nanoparticle tracking analysis and imaging flow cytometry. Tumor burden and edema were quantified by 3D reconstruction. EVs and tumors were further monitored in glioma-bearing mice. Glioblastoma patients displayed a 5.5-fold increase in circulating EVs compared to healthy donors (p < 0.0001). Patients with higher EV levels had a significantly shorter overall survival and progression-free survival than patients with lower levels, and the plasma EV concentration was an independent prognostic parameter for overall survival. EV levels correlated with the extent of peritumoral FLAIR hyperintensity but not with the size of the contrast-enhancing tumor, and similar findings were obtained in mice. Postoperatively, EV concentrations decreased rapidly back to normal levels, and the magnitude of the decline was associated with the extent of tumor resection. EV levels remained low during stable disease, but increased again upon tumor recurrence. In some patients, EV resurgence preceded the magnetic resonance imaging (MRI) detectability of tumor relapse. Our findings suggest that leakiness of the blood-brain barrier may primarily be responsible for the high circulating EV concentrations in glioblastoma patients. Elevated EVs reflect tumor presence, and their quantification may thus be valuable in assessing disease activity.

Immune system-related plasma extracellular vesicles in healthy aging.

To identify age-related plasma extracellular vehicle (EVs) phenotypes in healthy adults. EV proteomics by high-resolution mass spectrometry to evaluate EV protein stability and discover age-associated EV proteins (n=4 with 4 serial freeze-thaws each); validation by high-resolution flow cytometry and EV cytokine quantification by multiplex ELISA (n=28 healthy donors, aged 18-83 years); quantification of WI-38 fibroblast cell proliferation response to co-culture with PKH67-labeled young and old plasma EVs. The EV samples from these plasma specimens were previously characterized for bilayer structure, intra-vesicle mitochondria and cytokines, and hematopoietic cell-related surface markers. Compared with matched exo-EVs (EV-depleted supernatants), endo-EVs (EV-associated) had higher mean TNF-α and IL-27, lower mean IL-6, IL-11, IFN-γ, and IL-17A/F, and similar mean IL-1β, IL-21, and IL-22 concentrations. Some endo-EV and exo-EV cytokine concentrations were correlated, including TNF-α, IL-27, IL-6, IL-1β, and IFN-γ, but not IL-11, IL-17A/F, IL-21 or IL-22. Endo-EV IFN-γ and exo-EV IL-17A/F and IL-21 declined with age. By proteomics and confirmed by flow cytometry, we identified age-associated decline of fibrinogen (FGA, FGB and FGG) in EVs. Age-related EV proteins indicated predominant origins in the liver and innate immune system. WI-38 cells (>95%) internalized similar amounts of young and old plasma EVs, but cells that internalized PKH67-EVs, particularly young EVs, underwent significantly greater cell proliferation. Endo-EV and exo-EV cytokines function as different biomarkers. The observed healthy aging EV phenotype reflected a downregulation of EV fibrinogen subpopulations consistent with the absence of a pro-coagulant and pro-inflammatory condition common with age-related disease.

MiRNA patterns in male LUSC patients - the 3-way mirror: Tissue, plasma and exosomes

Lung cancer remains one of the leading causes of cancer-related deaths worldwide. It is classified into two main histological groups: non-small cell lung cancer (NSCLC) and small cell lung cancer. Improving the outcome of cancer patients could be possible by enhancing the early diagnosis. In the current study, we evaluated the levels of three microRNAs - miR-21-5p, miR-155-5p, and miR-181a-5p in tumor (TT) vs adjacent normal tissue (NT), as well as their expression levels in plasma and extracellular vesicles (EVs) from plasma in lung squamous cell carcinoma (LUSC) male patients vs healthy individuals as means to identify a panel of miRNAs that could serve as novel biomarkers for the diagnosis of LUSC in male patients. Matched paired tissue samples from male LUSC (n=40) patients were used for miRNA expression analysis. MiR-21-5p and miR-155-5p in tumor tissue were overexpressed, while underexpression of miR-181a-5p was observed in LUSC TT vs NT. These results were further validated in the TCGA LUSC dataset, considering 279 male samples. These alterations of miR-21-5p, miR-181a-5p, and miR-155-5p in tumor tissue are also present in plasma and plasma extracellular vesicles in LUSC male patients. In addition, ROC curves were performed to assess the sensitivity and specificity of different combinations of these miRNAs, confirming a high diagnostic accuracy for LUSC of up to 88 % in male subjects. The expression levels in tissue samples and the abundance in plasma and plasma EVs of the three miRNAs combined - miR-21-5p, miR-155-5p and miR-181a-5p – could be considered for further studies on biomarkers for the early detection of LUSC in male subjects.

Abstract 1074: Plasma EV profiling facilitates low abundance biomarker discovery in pancreatic cancer

Abstract The lack of reliable biomarkers for early detection of pancreatic ductal adenocarcinoma (PDAC) results in poor prognosis due to advanced disease at diagnosis. Biopsies for pancreatic cancer are known to be particularly difficult to perform because of the location of the pancreas and low volume of primary tumors that metastasize aggressively. Currently, there is no blood test or other screening modality in use, for stratification of individuals with higher-than-average risk (5-8-fold) of developing PDAC in their lifetime. Given this existing void in the US and worldwide, an FDA-compliant, minimally invasive, quantitative biomarker test for the early detection of PDAC would be critical for screening subpopulations with, a) inherent genetic or familial predisposition; history of chronic pancreatitis; c) precursor lesions of pancreas; and d) older patients (&amp;gt;50 years) with new onset diabetes or sudden weight loss. Extracellular vesicles (EVs) are shed by normal and cancer cells and carry a rich molecular cargo that can be leveraged for biomarker discovery. Whereas molecular profiling of bio-fluids poses intrinsic limitations for detection of low abundant, disease-specific biomarkers due to matrix effects; EVs, on the other hand, offer promise as a robust and minimally invasive biomarker resource. Mass spectrometry data were developed in our laboratory, based on multi-omics (proteomics, lipidomics and metabolomics) analyses of plasma EVs derived from patients diagnosed with early-stage PC (N=60), pancreatitis (N=39), precursor lesions of pancreas (N=45) as well as normal controls (N=50). These clinically annotated samples were made available by the Georgetown University Medical Center (GUMC) repository. Feature selection using a training-validation design allowed the development of a multiplexed biomarker panel comprising of 12-analytes (5-lipids, 2-metabolites and 5-proteins) that can robustly stratify early-stage PC from normal controls with high accuracy (AUC&amp;gt;95%). Availability of a FDA compliant, multi-analyte-based classification algorithm that can stratify patients with precursor lesions of the pancreas that are at potential risk of progression to PC with &amp;gt; 90% specificity and sensitivity is a critical clinical need. Refinement of panel to improve positive predictive value as well as identification of markers predictive of progression of precursor lesions to malignant transformation is ongoing. Citation Format: Shivani Bansal, Shu Wang, Yaoxiang Li, Sunil Bansal, Jill Smith, John B. Tyburski, Keith Unger, Amrita Cheema. Plasma EV profiling facilitates low abundance biomarker discovery in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1074.

Abstract 3630: Measuring EGFr on extracellular vesicles in human plasma samples

Abstract Introduction: Extracellular vesicles (EVs), secreted extracellularly by almost all types of cells, play a pivotal role in intercellular communication and have emerged as valuable indicators in disease progression. Their potential for cancer diagnostics and monitoring is particularly noteworthy. Epidermal growth factor receptor (EGFr) is a major driver of several cancers and serve as an important target or co-target in cancer treatment. The purpose of this study was to develop an assay for measuring EGFr on EVs directly in plasma samples. Additionally three assays were developed to measure the total concentration of plasma EVs. Methods: Recognizing the expected low concentrations of EGFr on EVs, the immunoassays were developed using Single molecule array (Simoa) technology, which has shown up to a 1000-fold improvement in sensitivity as compared to conventional immunoassay approaches. Commercial available calibrator material and antibodies against surface markers (EGFr, CD9, CD63 and CD81) were used to develop four assays: CD81-EGFr, CD81-CD9, CD81-CD63, and CD9-CD63. Plasma samples from healthy individuals (n=13) and small cohorts of various cancer patients (n=30, lung, colorectal, ovarian) were used for development, validation and testing. Results: Each assay was tested for dilution linearity, limit of detection, analytical variation and pre-analytical stability of EVs. EGFr on EVs was lower in cancer patients (median: 489 × 106 EVegfr/mL) compared with healthy individuals (median: 663 × 106 EVegfr/mL). Conversely, total EV concentrations were markedly higher in plasma from cancer patients compared with healthy individuals (CD81-CD9: 9157 vs 4088, CD81-CD63: 3634 vs 1582, CD9-CD63: 9538 vs 1210, median values x106 EV/mL). Positive correlations were observed among the total EV assays (r=0.6, p&amp;lt;0.0001). Conclusion: The developed assays allow measurement of EGFr on EVs and total EVs in human plasma samples. Notable, total EV concentrations were highly increased in cancer as compared with healthy individuals. The assays are now ready for a comprehensive validation using large cohorts of cancer samples. Citation Format: Dorte Aa. Olsen, Torben F. Hansen, Ivan Brandslund, Jonna S. Madsen. Measuring EGFr on extracellular vesicles in human plasma samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3630.

Profiling plasma alterations of extracellular vesicles in patients with acutely decompensated cirrhosis and bacterial infection.

Extracellular vesicles (EVs) modulate inflammation, coagulation and vascular homeostasis in decompensated cirrhosis. To characterize the profile of plasmatic EVs in patients with decompensated cirrhosis and bacterial infections and evaluate the association between EVs and the development of hemostatic complications. We measured the levels of EVs using high-sensitivity flow cytometry and phospholipid-dependent clotting time (PPL) in a prospective cohort of hospitalized patients with acutely decompensated cirrhosis with versus without bacterial infections. A separate cohort of patients with bacterial infections without cirrhosis was also enrolled. We measured endothelium-, tissue factor (TF)-bearing, platelet- and leukocyte-derived EVs. In patients with infections, EVs were reassessed upon resolution of infection. Bleeding and thrombotic complications were recorded during 1-year follow-up. Eighty patients with decompensated cirrhosis were recruited (40 each with and without bacterial infections). Electron microscopy confirmed the presence of plasma EVs. Despite no difference in total EVs and PPL, patients with cirrhosis and infection had significantly higher TF+ EVs, P-Selectin+ EVs (activated platelet-derived), CD14+ EVs (monocyte/macrophages derived) and CD14+ TF+ EVs versus those with cirrhosis without infection. Upon infection resolution, levels of these EVs returned to those without infection. Patients with infections showed a significant association between reduced P-Selectin+ EVs and bleeding complications (HR 8.0 [95%CI 1.3-48.1]), whereas high levels of leukocyte-derived EVs (CD45+) and CD14+ EVs were significantly associated with thrombotic complications (HR 16.4 [95%CI 1.7-160] and 10.9 [95%CI 1.13-106], respectively). Results were confirmed in a validation cohort. Bacterial infections are associated with particular alterations of plasma EVs profile in decompensated cirrhosis. Bacterial infections trigger the release of EVs originating from various cell types, which may tip the precarious hemostatic balance of patients with acutely decompensated cirrhosis towards hyper- or hypocoagulability.

Next‐generation sequencing reveals that miR‐16‐5p, miR‐19a‐3p, miR‐451a, and miR‐25‐3p cargo in plasma extracellular vesicles differentiates sedentary young males from athletes

AbstractA sedentary lifestyle and Olympic participation are contrary risk factors for global mortality and incidence of cancer and cardiovascular disease. Extracellular vesicle miRNAs have been described to respond to exercise. No molecular characterization of young male sedentary people versus athletes is available; so, our aim was to identify the extracellular vesicle miRNA profile of chronically trained young endurance and resistance male athletes compared to their sedentary counterparts. A descriptive case–control design was used with 16 sedentary young men, 16 Olympic male endurance athletes, and 16 Olympic male resistance athletes. Next‐generation sequencing and RT‐qPCR and external and internal validation were performed in order to analyze extracellular vesicle miRNA profiles. Endurance and resistance athletes had significant lower levels of miR‐16‐5p, miR‐19a‐3p, and miR‐451a compared to sedentary people. Taking all together, exercise‐trained miRNA profile in extracellular vesicles provides a differential signature of athletes irrespective of the type of exercise compared to sedentary people. Besides, miR‐25‐3p levels were specifically lower in endurance athletes which defines its role as a specific responder in this type of athletes. In silico analysis of this profile suggests a role in adaptive energy metabolism in this context that needs to be experimentally validated. Therefore, this study provides for the first time basal levels of circulating miRNA in extracellular vesicles emerge as relevant players in intertissue communication in response to chronic exercise exposure in young elite male athletes.

The fluorochrome-to-protein ratio is crucial for the flow cytometric detection of tissue factor on extracellular vesicles

Extracellular vesicles (EVs) have crucial roles in hemostasis and coagulation. They sustain coagulation by exposing phosphatidylserine and initiate clotting by surface expression of tissue factor (TF) under inflammatory conditions. As their relevance as biomarkers of coagulopathy is increasingly recognized, there is a need for the sensitive and reliable detection of TF+ EVs, but their flow cytometric analysis is challenging and has yielded controversial findings for TF expression on EVs in the vascular system. We investigated the effect of different fluorochrome-to-protein (F/P) ratios of anti-TF-fluorochrome conjugates on the flow cytometric detection of TF+ EVs from activated monocytes, mesenchymal stem cells (MSCs), and in COVID-19 plasma. Using a FITC-labeled anti-TF antibody (clone VD8), we show that the percentage of TF+ EVs declined with decreasing F/P ratios. TF was detected on 7.6%, 5.4%, and 1.1% of all EVs derived from activated monocytes at F/P ratios of 7.7:1, 6.6:1, and 5.2:1. A similar decline was observed for EVs from MSCs and for EVs in plasma, whereas the detection of TF on cells remained unaffected by different F/P ratios. We provide clear evidence that next to the antibody clone, the F/P ratio affects the flow cytometric detection of TF+ EVs and should be carefully controlled.

Plasma extracellular vesicle microRNAs reflecting the therapeutic effect of the CBP/β-catenin inhibitor PRI-724 in patients with liver cirrhosis.

There is an unmet need for antifibrotic therapies to prevent the progression of liver cirrhosis. Previously, we conducted an exploratory trial to assess the safety and antifibrotic efficacy of PRI-724, a selective CBP/β-catenin inhibitor, in patients with liver cirrhosis. PRI-724 was well tolerated and exerted a potential antifibrotic effect. Here, we investigated whether the profiles of circulating microRNAs packaged in extracellular vesicles (EV-miRNAs) are associated with responses to liver fibrosis treatments. Eighteen patients who received PRI-724 for 12weeks in a phase 1/2a study were classified as responders (n = 10) or non-responders (n = 8) based on changes in liver stiffness. Plasma samples were obtained before and after PRI-724 administration and the levels of EV-miRNAs were analyzed. Three miRNAs (miR-6510-5p, miR-6772-5p, and miR-4261) were identified as predictors of response or non-response to PRI-724, and the levels of three other miRNAs (miR-939-3p, miR-887-3p, and miR-7112-5p) correlated with the efficacy of treatment. Expression of miR-887-3p was detected in hepatocytes and was decreased significantly in liver tissue following PRI-724 treatment. In addition, transfection of a miR-887-3p mimic activated hepatic stellate cells. Thus, decreases in the miR-887-3p level in blood may reflect recovery from liver fibroses in patients with liver cirrhosis treated with PRI-724, although further validation studies are warranted to confirm this.