Extracellular Vesicles Biomarkers Research Articles

Extracellular vesicles as personalized medicine.

Extracellular vesicles (EVs) are released from all cells in the body, forming an important intercellular communication network that contributes to health and disease. The contents of EVs are cell source-specific, inducing distinct signaling responses in recipient cells. The specificity of EVs and their accumulation in fluid spaces that are accessible for liquid biopsies make them highly attractive as potential biomarkers and therapies for disease. The duality of EVs as favorable (therapeutic) or unfavorable (pathological) messengers is context dependent and remains to be fully determined in homeostasis and various disease states. This review describes the use of EVs as biomarkers, drug delivery vehicles, and regenerative therapeutics, highlighting examples involving viral infections, cancer, and neurological diseases. There is growing interest to provide personalized therapy based on individual patient and disease characteristics. Increasing evidence suggests that EV biomarkers and therapeutic approaches are ideal for personalized medicine due to the diversity and multifunctionality of EVs.

Extracellular Vesicles as Markers of Liver Function: Optimized Workflow for Biomarker Identification in Liver Disease.

Liver diseases represent a significant global health burden, necessitating the development of reliable biomarkers for early detection, prognosis, and therapeutic monitoring. Extracellular vesicles (EVs) have emerged as promising candidates for liver disease biomarkers due to their unique cargo composition, stability, and accessibility in various biological fluids. In this study, we present an optimized workflow for the identification of EVs-based biomarkers in liver disease, encompassing EVs isolation, characterization, cargo analysis, and biomarker validation. Here we show that the levels of microRNAs miR-10a, miR-21, miR-142-3p, miR-150, and miR-223 were different among EVs isolated from patients with nonalcoholic fatty liver disease and autoimmune hepatitis. In addition, IL2, IL8, and interferon-gamma were found to be increased in EVs isolated from patients with cholangiocarcinoma compared with healthy controls. By implementing this optimized workflow, researchers and clinicians can improve the identification and utilization of EVs-based biomarkers, ultimately enhancing liver disease diagnosis, prognosis, and personalized treatment strategies.

Circulating Endothelial Cell-Derived Extracellular Vesicles Biomarker of Endothelial Vasomotor Dysfunction in Adults with Obesity

The prevalence of obesity continues to increase in the United States, more than one-third of the adults in the United States have obesity. Experimental and clinical studies have shown that a proatherogenic endothelial phenotype is a major consequence of increased adiposity and underlies obesity-related cardiovascular disease (CVD). Clinical interest in circulating extracellular vesicles, particularly endothelial cell-derived microvesicles (EMVs), has increased given their potential pathogenic role in vascular dysfunction and CVD risk and events. We have previously demonstrated that elevated EMVs are associated with decreased endothelium-dependent vasodilation. In addition to diminished endothelial vasodilation, obesity is associated with increased endothelin (ET)-1-mediated vasoconstrictor tone. It is currently unknown if circulating EMVs is also linked to heightened ET-1 system activity in adults with obesity. Accordingly, the aim of this study was to determine if EMVs are associated with increased ET-1-mediated vasoconstrictor tone in adults with obesity. Thirty-six, mid-life adults (45-63 years) were studied: 18 normal weight (12M/6F; age: 56±1 yr; BMI: 23.3±0.4 kg/m2; body fat: 25.2±2.1 %) and 18 obese (12M/6F; age: 53±1 yr; BMI: 31.9±0.4 kg/m2; body fat: 38.7±1.6 %). All subjects were free of overt cardiometabolic disease. EMV identification (CD31+/CD42b-) and concentration in peripheral blood were determined by flow cytometry. Forearm blood flow (FBF: via plethysmography) was assessed in response to intra-arterial infusions of the selective ETA receptor blockade (BQ-123: 100 nmol/min for 60 min), acetylcholine (4.0, 8.0 and 16.0 mg/100 mL tissue/min) and sodium nitroprusside (1.0, 2.0 and 4.0 mg/100 mL tissue/min). Circulating EMV levels were ~75% higher (P<0.05) in adults with obesity (139±12 EMV/mL) compared with normal weight (79±6 EMV/mL) adults. BQ-123 elicited a significantly greater increase in FBF in adults with obesity (~30%) than normal weight (~2%) adults, indicative of greater ET-1-mediated vasoconstrictor tone. FBF response to acetylcholine was significantly lower (~30%) in the obese (from 4.3±0.2 to 10.6±0.6 mL/100 mL tissue/min) vs the normal weight (from 4.2±0.2 to 15.1±0.6 mL/100 mL tissue/min) group. There was no significant difference in FBF responses to sodium nitroprusside between the groups. Circulating EMVs were significantly and positively associated with the peak FBF response to BQ-123 (r=0.39) and inversely related with total FBF response to acetylcholine (r=-0.44). Higher circulating EMVs in adults with obesity represents a novel biomarker of endothelial vasomotor dysfunction and a potential mediator of impaired vascular function and disease risk. Nothing to disclose This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Depletion of abundant plasma proteins for extracellular vesicle proteome characterization: benefits and pitfalls

Blood extracellular vesicles (EVs) play essential roles in cell–cell communication and their molecular cargo is a promising source of disease biomarkers. However, proteomic characterization of plasma-derived EVs is challenged by the presence of highly abundant plasma proteins, which limits the detection of less abundant proteins, and by the low number of EVs in biological fluids. The aim of this study was to investigate if the removal of abundant plasma proteins prior to EV isolation could improve plasma-derived EV characterization by LC–MS/MS and expand the proteome coverage. Plasma depletion was performed using a single-use spin column and EVs were isolated from only 100 µL of non-depleted and depleted plasma by size exclusion chromatography. Afterwards, EVs were characterized by nanoparticle tracking analysis and mass spectrometry–based proteomics using a data-independent acquisition approach. Depleted plasma-derived EVs had higher particle concentrations and particle-to-protein ratios. Depletion did increase the protein coverage with a higher number of identifications in EVs from depleted plasma (474 proteins) than from non-depleted (386 proteins). However, EVs derived from non-depleted plasma carried a slightly higher number of common EV markers. Overall, our findings suggest that plasma depletion prior to EV isolation by size exclusion chromatography provides higher yield and protein coverage, but slightly lower identification of EV markers. This study also showed the possibility to characterize the proteome of EVs derived from small plasma volumes, encouraging the clinical feasibility of the discovery of EV biomarkers.

Abstract 6515: Pancreatic ductal adenocarcinoma (PDAC) early detection

Abstract Introduction Pancreatic ductal adenocarcinoma (PDAC) is the most common form of pancreatic cancer and is one of the deadliest cancer in the U.S., with a 5-year survival rate of just 11%. It is expected that ~62,000 new cases will be diagnosed in the US in 2023 and >70% of those will be at the regional or distant state, when curative resection is no longer an option. It is imperative that tools enabling early disease detection (stages I and II) are developed to improve patient survival outcomes. Here, we report the results of a study on the utility of extracellular vesicles (EVs) for early PDAC detection. Methods Our case-control training set was comprised of 75 pathologically confirmed PDAC cases (Stage I = 31, Stage II = 44) and 640 controls (including 11 subjects with pancreatitis) for EV biomarker and algorithm selection via machine learning. EVs from plasma were isolated using a proprietary technology, then EV-bound proteins of interest were analyzed via an immunoassay. A second independently collected cohort of 20 confirmed PDAC cases (Stage I = 10, Stage II = 10) and 27 controls (including 9 patients newly diagnosed with diabetes) was used for validation. Results The machine learning analysis using EV-isolated proteins generated a signature that utilized 8 different biomarkers, with an AUC of 0.989 (95% CI: 0.980 - 0.998) in the training set and an AUC of 0.987 (CI: 0.964 - 1.000) in the validation set. For the validation set, the sensitivity was 95% (CI: 76.4% - 99.1%) and the specificity was 92.6% (CI: 76.6% - 97.9%), with 10 out of 10 stage I cases and 9 out of 10 stage II cases correctly classified. Conclusions The ability to alter the future outcomes of PDAC patients will be predicated on development of a new generation of early-detection biomarkers and technologies. The use of EV protein signatures, a new class of cell-free biomarker, permits detection at high sensitivity and specificity, as demonstrated for the independently collected validation cohort. Studies aimed to assess this test for high-risk patients (family history of PDAC, known germline mutations, precursor lesions, hereditary pancreatitis, new onset diabetes will continue towards the establishment of real-world evidence. Citation Format: Juan P. Hinestrosa, Harmeet Dhani, Gregor Schroeder, Jean M. Lewis, Heath I. Balcer, Razelle Kurzrock, Dove Keith, Rosalie Sears, Paul Billings. Pancreatic ductal adenocarcinoma (PDAC) early detection. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6515.

Abstract 2103: Immunophenotyping of extracellular vesicles isolated from lymphatic exudate identifies CD24 as a marker for lymph node metastases in oral cavity squamous cell carcinoma

Abstract Background: Squamous cell carcinoma of the oral cavity (OSCC) is debilitating and fatal with a high risk of lymph node metastases. One of the key problems is that currently there is no robust molecular biomarker to determine whether the tumor has spread or is at risk of spreading to the regional lymph nodes, the first echelon that OSCC spreads to. Extracellular vesicles (EVs) are functional nanoparticles that are bound by natural protein-lipid bilayers. They are deliberately packaged and proactively secreted by all types of cells and serve as intercellular communication vehicles. Tumors release an excess of EVs which are loaded with the molecular and genetic cargo of the parental tumor cells. Methods: Following ethical approval and written informed consent, pre-surgical plasma as well as matched post-surgical lymphatic drainage fluid were collected from 20 OSCC patients (nodal disease n=6, no node n=14), and control plasma was also collected from healthy donors. EVs were isolated by ultracentrifugation, quantified and characterized by nanoparticle tracking analysis, transmission electron microscopy, and western blot. Immune profiling of 37 EV surface markers was determined using flow cytometry with the MACSPlex Exosome kit. Results: Lymphatic exudate was greatly enriched in EVs in comparison to plasma. Common EV tetraspanins, platelet markers, cancer-related proteins, as well as characteristic markers of immune cells were detected in both plasma and lymphatic exudate EVs based on normalized median fluorescence intensity (nMFI). The presence of OSCC led to an altered composition of blood cell-derived EVs. Elevated levels of CD3, CD25, and CD86, and cancer stem cell marker CD133 were observed in the plasma EVs. However, there were no significant changes in EV markers in plasma between patients with and without lymph node metastasis. Notably, EVs isolated from plasma and lymphatic exudate revealed completely divergent signatures of EV surface markers. Among them, cancer-related protein CD24 was found to be the most highly expressed EV marker in lymphatic exudate from patients with nodal disease (nMFI 1.28±0.50 versus 0.84±0.32, p<0.05) and likewise correlated with advanced disease stages (nMFI 1.17±0.40 versus 0.70±0.27, p<0.05). Conclusions: Plasma-derived EVs are promising non-invasive biomarkers for cancer detection. This study shows that lymphatic exudate is a better source of EV biomarkers due to its high abundance of tumor-related factors directly from draining lymph nodes. In addition, CD24, as reported, is indicative of an immunosuppressive tumor microenvironment and it may serve as a predictor for lymph node metastases and progression of OSCC. These findings shed new light on the understanding of OSCC metastases and provide impetus for consideration of CD24-based liquid biopsy testing and possibly novel immunotherapy. Citation Format: Xinyu Qu, Leanne Lee Leung, Cherrie Wing Kei Ng, Hiu Ching Chan, Zigui Chen, Katie Meehan, Xianhai Zeng, Jason Ying Kuen Chan. Immunophenotyping of extracellular vesicles isolated from lymphatic exudate identifies CD24 as a marker for lymph node metastases in oral cavity squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2103.

Small Extracellular Vesicle Biomarkers in Breast Cancer: A Real-Time Snapshot for Early Diagnosis and Prognosis?

BioanalysisAhead of Print EditorialSmall extracellular vesicle biomarkers in breast cancer: a real-time snapshot for early diagnosis and prognosis?Siva Nageswara Rao Gajula & Lakshmi Vineela NallaSiva Nageswara Rao Gajula https://orcid.org/0000-0003-0449-4282Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education & Research, Hyderabad, Telangana, 500037, IndiaSearch for more papers by this author & Lakshmi Vineela Nalla *Author for correspondence: E-mail Address: lakshmivineela@kluniversity.inhttps://orcid.org/0000-0002-6077-1099Department of Pharmacy, Koneru Lakshmaiah Education Foundation, Vaddeswaram, AP, 522302, IndiaSearch for more papers by this authorPublished Online:8 May 2023https://doi.org/10.4155/bio-2023-0038AboutSectionsView ArticleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinkedInReddit View articleKeywords: biomarkersbreast cancerexomeresLC–MS/MSliquid biopsynext-generation sequencingprotein quantificationproteomicssmall extracellular vesiclessupermeres

MP14-05 EXTRACELLULAR VESICLE BIOMARKER SIGNATURE DETECTION PLATFORM FOR GUIDING CANCER DETECTION AND THERAPY

You have accessJournal of UrologyCME1 Apr 2023MP14-05 EXTRACELLULAR VESICLE BIOMARKER SIGNATURE DETECTION PLATFORM FOR GUIDING CANCER DETECTION AND THERAPY Thomas Osinski, Samuel Walker, Karen Doersch, Jonathan Flax, and James McGrath Thomas OsinskiThomas Osinski More articles by this author , Samuel WalkerSamuel Walker More articles by this author , Karen DoerschKaren Doersch More articles by this author , Jonathan FlaxJonathan Flax More articles by this author , and James McGrathJames McGrath More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003234.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Extracellular Vesicles (EVs) have tremendous potential in cancer diagnostics and personalized cancer therapeutics. They are abundant in all biofluids, carry molecular markers of their cell-of-origin and can be readily obtained via noninvasive techniques. Current EV biomarker assessments have several limitiations. Pooled EVs from samples have low detection sensitivity for less abundant biomarkers and preclude colocalization of biomarkers on individual EVs. Currently, expensive specialized devices requiring large biofluid inputs are needed for more detailed EV analysis. Here, we develop an easy to use and inexpensive device that permits optical detection of multiple markers on individual EVs using only 10 µl of serum. This work investigates whether the microfluidic strategy we call ‘catch and display for liquid biopsy [CAD-LB]’ can detect biomarkers on single EVs. We also sought to determine the dynamic range of accurate quantitation using purified EVs and serum and validate detection of immune checkpoint proteins (PD-L1 and/or PD-1), which may help to distinguish immune checkpoint immunotherapy (ICI) responders from non-responders in bladder cancer. METHODS: For this study EVs were derived from: 1. ultracentrifuge purified urinary EVs; 2. EVs from media of 5637 bladder cancer and primary bladder epithelium cell lines and; 3. Serum from patients with advanced urothelial carcinoma or healthy controls. EVs were labeled with the pan-EV marker carboxyfluorescein succinimidyl ester and fluorescently labeled primary antibodies. Small volumes (10 µL) of solutions were captured on our membrane with nanopores in a transparent membrane and imaged using fluorescence microscopy. Detection range was assessed by serial dilutions of EVs. EV surface antigen labeling was assessed by CAD-LB. RESULTS: 1. Counting curves demonstrate a wide dynamic range of CAD-LB (102 – 106 EVs) for purified EVs while serum plateaus at lower inputs (∼104 EVs). 2. CAD-LB detects PD-1 and PD-L1 biomarkers in urothelial carcinoma patients’ serum. 3. CAD-LB detects T cell biomarker CD3 on approximately 1-2% of EVs in healthy control serum. CONCLUSIONS: CAD-LB can detect rare and clinically significant EV associated biomarkers in conditioned medium and patient serum samples. Furthermore, CAD-LB provides single EV characterization with small sample volumes. These qualities make CAD-LB a potentially useful tool to help discover novel markers that could aid in diagnosis and treatment decisions for cancer patients. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e183 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Thomas Osinski More articles by this author Samuel Walker More articles by this author Karen Doersch More articles by this author Jonathan Flax More articles by this author James McGrath More articles by this author Expand All Advertisement PDF downloadLoading ...

Macroporous Epoxy-Based Monoliths Functionalized with Anti-CD63 Nanobodies for Effective Isolation of Extracellular Vesicles in Urine

Extracellular vesicles (EVs) have enormous potential for the implementation of liquid biopsy and as effective drug delivery means, but the fulfilment of these expectations requires overcoming at least two bottlenecks relative to their purification, namely the finalization of reliable and affordable protocols for: (i) EV sub-population selective isolation and (ii) the scalability of their production/isolation from complex biological fluids. In this work, we demonstrated that these objectives can be achieved by a conceptually new affinity chromatography platform composed of a macroporous epoxy monolith matrix functionalized with anti-CD63 nanobodies with afflux of samples and buffers regulated through a pump. Such a system successfully captured and released integral EVs from urine samples and showed negligible unspecific binding for circulating proteins. Additionally, size discrimination of eluted EVs was achieved by different elution approaches (competitive versus pH-dependent). The physical characteristics of monolith material and the inexpensive production of recombinant nanobodies make scaling-up the capture unit feasible and affordable. Additionally, the availability of nanobodies for further specific EV biomarkers will allow for the preparation of monolithic affinity filters selective for different EV subclasses.

Multiplexed analysis of EV reveals specific biomarker composition with diagnostic impact

Exosomes and extracellular vesicles (EV) are increasingly being explored as circulating biomarkers, but their heterogenous composition will likely mandate the development of multiplexed EV technologies. Iteratively multiplexed analyses of near single EVs have been challenging to implement beyond a few colors during spectral sensing. Here we developed a multiplexed analysis of EV technique (MASEV) to interrogate thousands of individual EVs during 5 cycles of multi-channel fluorescence staining for 15 EV biomarkers. Contrary to the common belief, we show that: several markers proposed to be ubiquitous are less prevalent than believed; multiple biomarkers concur in single vesicles but only in small fractions; affinity purification can lead to loss of rare EV subtypes; and deep profiling allows detailed analysis of EV, potentially improving the diagnostic content. These findings establish the potential of MASEV for uncovering fundamental EV biology and heterogeneity and increasing diagnostic specificity.

Extracellular Vesicles in Liquid Biopsies as Biomarkers for Solid Tumors

Extracellular vesicles (EVs) are secreted by all living cells and are ubiquitous in every human body fluid. They are quite heterogeneous with regard to biogenesis, size, and composition, yet always reflect their parental cells with their cell-of-origin specific cargo loading. Since numerous studies have demonstrated that EV-associated proteins, nucleic acids, lipids, and metabolites can represent malignant phenotypes in cancer patients, EVs are increasingly being discussed as valuable carriers of cancer biomarkers in liquid biopsy samples. However, the lack of standardized and clinically feasible protocols for EV purification and characterization still limits the applicability of EV-based cancer biomarker analysis. This review first provides an overview of current EV isolation and characterization techniques that can be used to exploit patient-derived body fluids for biomarker quantification assays. Secondly, it outlines promising tumor-specific EV biomarkers relevant for cancer diagnosis, disease monitoring, and the prediction of cancer progression and therapy resistance. Finally, we summarize the advantages and current limitations of using EVs in liquid biopsy with a prospective view on strategies for the ongoing clinical implementation of EV-based biomarker screenings.

A Versatile Design-Enabled Analysis of Circulating Extracellular Vesicles in Disease Diagnosis.

Circulating extracellular vesicles (EVs) are considered as potential biomarkers for treatment and diagnosis of many diseases. Most of the existing methods for the EV analysis only have a single function and thus reveal limited information carried by EVs. Herein, a phosphatidylserine-targeting peptide-facilitated design that enables the versatile analysis of circulating EVs for varying requirement is proposed. In the design, DNA probes are inserted into the EV membrane through hydrophobic interactions, and accelerate the removal of protective shielding from DNA-gated metal-organic framework, thereby releasing a large number of methylene blue molecules to amplify the electrochemical signal. Electrochemical results demonstrate equally high sensitivities toward the quantification of EVs derived from different cell sources using an indiscriminative DNA probe. More importantly, the probe can be endowed with extended function for more accurate classification of cell-specific features through the identification of specific EV biomarkers, and demonstrates the potential use in the diagnosis of cardiovascular in a principle-of-proof study for clinical application. Therefore, the method provides a versatile design for the identification of EV features, and may address the needs of clinical diagnosis in the future.

Plasma extracellular vesicle messenger RNA profiling identifies prognostic EV signature for non-invasive risk stratification for survival prediction of patients with pancreatic ductal adenocarcinoma

BackgroundThe prognosis of pancreatic ductal adenocarcinoma (PDAC) is one of the most dismal of all cancers and the median survival of PDAC patients is only 6–8 months after diagnosis. While decades of research effort have been focused on early diagnosis and understanding of molecular mechanisms, few clinically useful markers have been universally applied. To improve the treatment and management of PDAC, it is equally relevant to identify prognostic factors for optimal therapeutic decision-making and patient survival. Compelling evidence have suggested the potential use of extracellular vesicles (EVs) as non-invasive biomarkers for PDAC. The aim of this study was thus to identify non-invasive plasma-based EV biomarkers for the prediction of PDAC patient survival after surgery.MethodsPlasma EVs were isolated from a total of 258 PDAC patients divided into three independent cohorts (discovery, training and validation). RNA sequencing was first employed to identify differentially-expressed EV mRNA candidates from the discovery cohort (n = 65) by DESeq2 tool. The candidates were tested in a training cohort (n = 91) by digital droplet polymerase chain reaction (ddPCR). Cox regression models and Kaplan–Meier analyses were used to build an EV signature which was subsequently validated on a multicenter cohort (n = 83) by ddPCR.ResultsTranscriptomic profiling of plasma EVs revealed differentially-expressed mRNAs between long-term and short-term PDAC survivors, which led to 10 of the top-ranked candidate EV mRNAs being tested on an independent training cohort with ddPCR. The results of ddPCR enabled an establishment of a novel prognostic EV mRNA signature consisting of PPP1R12A, SCN7A and SGCD for risk stratification of PDAC patients. Based on the EV mRNA signature, PDAC patients with high risk displayed reduced overall survival (OS) rates compared to those with low risk in the training cohort (p = 0.014), which was successfully validated on another independent cohort (p = 0.024). Interestingly, the combination of our signature and tumour stage yielded a superior prognostic performance (p = 0.008) over the signature (p = 0.022) or tumour stage (p = 0.016) alone. It is noteworthy that the EV mRNA signature was demonstrated to be an independent unfavourable predictor for PDAC prognosis.ConclusionThis study provides a novel and non-invasive prognostic EV mRNA signature for risk stratification and survival prediction of PDAC patients.

Abstract 17: Ultra-early Activation Of Neuroinflammatory Cascade Following Acute Stroke: Plasma And Extracellular Vesicle Biomarkers From A Mobile Stroke Unit

Background: Neuroinflammation is ubiquitous in acute stroke and worsens outcome. However, the precise timing of the inflammatory response is unknown, hindering the design of acute anti-inflammatory therapeutic interventions. We used a mobile stroke unit (MSU) to identify the onset of the neuroinflammatory cascade within minutes of symptom onset. Methods: The study is a prospective, cohort investigation of ultra-early blood- and extracellular vesicle (EV)-derived markers of neuroinflammation and outcome in acute stroke. Blood was obtained on the MSU with head CT, and from healthy controls. Plasma biomarkers were analyzed with ELISA, SIMOA and ECL. EVs were isolated with HSP pull down. Confirmed strokes, mimics and healthy controls were compared. Variables included demographics, mRS, NIHSS and discharge disposition. Results: Forty one adults were analyzed, including 15 patients treated on the MSU between August 2021 and April 2022, and 26 controls. For MSU patients, median age was 74 (range 36-97) years, 60% were female, and 80% white. Ten (67%) were diagnosed as stroke, with 8 (53%) confirmed and 2 likely TIA or stroke averted by thrombolysis; 5 were stroke mimics. For strokes, median initial NIHSS score was 11 (range 4-19) and 6 (75%) received tPA. Blood was obtained a median of 58 (range 36-133) minutes after symptom onset. Within 36 minutes after stroke, plasma interleukin-6 (IL-6), neurofilament light chain (NfL), ubiquitin C-terminal hydrolase L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) were elevated by as much as 10 times normal. In EVs, matrix metalloproteinase-9 (MMP-9), chemokine (C-X-C motif) ligand 4 (CXCL4), C-reactive protein (CRP), IL-6, osteopontin (OPN) and platelet and endothelial cell adhesion molecule 1 (PECAM1) were elevated. Inflammatory markers increased rapidly in the first two hours, and continued rising for 24 hours. Conclusions: This study found the inflammatory cascade is activated as early as 36 minutes after stroke, and progresses rapidly. This is earlier than observed previously in humans, and suggests injury from neuroinflammation may occur faster than had been surmised. The findings may inform development of immunomodulatory therapies for acute stroke, and lead to new diagnostic tools and improved outcomes.

An in vitro approach to understand contribution of kidney cells to human urinary extracellular vesicles.

Extracellular vesicles (EV) are membranous particles secreted by all cells and found in body fluids. Established EV contents include a variety of RNA species, proteins, lipids and metabolites that are considered to reflect the physiological status of their parental cells. However, to date, little is known about cell-type enriched EV cargo in complex EV mixtures, especially in urine. To test whether EV secretion from distinct human kidney cells in culture differ and can recapitulate findings in normal urine, we comprehensively analysed EV components, (particularly miRNAs, long RNAs and protein) from conditionally immortalised human kidney cell lines (podocyte, glomerular endothelial, mesangial and proximal tubular cells) and compared to EV secreted in human urine. EV from cell culture media derived from immortalised kidney cells were isolated by hydrostatic filtration dialysis (HFD) and characterised by electron microscopy (EM), nanoparticle tracking analysis (NTA) and Western blotting (WB). RNA was isolated from EV and subjected to miRNA and RNA sequencing and proteins were profiled by tandem mass tag proteomics. Representative sets of EV miRNAs, RNAs and proteins were detected in each cell type and compared to human urinary EV isolates (uEV), EV cargo database, kidney biopsy bulk RNA sequencing and proteomics, and single-cell transcriptomics. This revealed that a high proportion of the in vitro EV signatures were also found in in vivo datasets. Thus, highlighting the robustness of our in vitro model and showing that this approach enables the dissection of cell type specific EV cargo in biofluids and the potential identification of cell-type specific EV biomarkers of kidney disease.

Biochemical Characterization of Human Salivary Extracellular Vesicles as a Valuable Source of Biomarkers.

Extracellular vesicles (EVs) are natural nanoparticles secreted under physiological and pathological conditions. Thanks to their diagnostic potential, EVs are increasingly being studied as biomarkers of a variety of diseases, including neurological disorders. To date, most studies on EV biomarkers use blood as the source, despite different disadvantages that may cause an impure isolation of the EVs. In the present article, we propose the use of saliva as a valuable source of EVs that could be studied as biomarkers in an easily accessible biofluid. Using a comparable protocol for the isolation of EVs from both liquid biopsies, salivary EVs showed greater purity in terms of co-isolates (evaluated by nanoparticle tracking analysis and Conan test). In addition, Raman spectroscopy was used for the identification of the overall biochemical composition of EVs coming from the two different biofluids. Even considering the limited amount of EVs that can be isolated from saliva, the use of Raman spectroscopy was not hampered, and it was able to provide a comprehensive characterization of EVs in a high throughput and repeatable manner. Raman spectroscopy can thus represent a turning point in the application of salivary EVs in clinics, taking advantage of the simple method of collection of the liquid biopsy and of the quick, sensitive and label-free biophotonics-based approach.

Plasma derived extracellular vesicle biomarkers of microglia activation in an experimental stroke model

Chronic microglia activation post-stroke is associated with worse neurological and cognitive outcomes. However, measurement of microglia activation in vivo is currently limited. Plasma derived extracellular vesicles (EVs) are cell-specific indicators that may allow for non-invasive measurement of microglia phenotype. The aim of this study was to identify activation-state specific microglia EVs (MEVs) in vitro followed by validation in an experimental stroke model. Following pro-inflammatory activation, MEVs contain the microglia protein TMEM119 alongside increased expression of the Toll-like receptor 4 co-receptor CD14. Immunoprecipitation followed by fluorescent nanoparticle tracking analysis (ONI Nanoimager) was used to confirm the isolation of TMEM119+/CD14+ EVs from rat plasma. Electron microscopy confirmed that TMEM119 and CD14 localize to the MEV membrane. To model ischemia, plasma was collected from 3-month wildtype Fischer344 rats prior to, 7 and 28 days after endothelin-1 or saline injection into the dorsal right striatum. Fluorescently labelled MEVs were directly measured in the plasma using nanoflow cytometry (Apogee A60 Microplus). We report a significant increase in circulating TMEM119+/CD14+ EVs 28-days post-stroke in comparison to baseline levels and saline-injected rats, which correlated weakly with stroke volume. TMEM119+/MHC-II+ EVs were also increased post-stroke in comparison to baseline and saline-injected animals. This study is the first to describe an EV biomarker of activated microglia detected directly in plasma following stroke and represents a future tool for the measurement of microglia activity in vivo.

Nanomaterials for Molecular Detection and Analysis of Extracellular Vesicles.

Extracellular vesicles (EVs) have emerged as a novel resource of biomarkers for cancer and certain other diseases. Probing EVs in body fluids has become of major interest in the past decade in the development of a new-generation liquid biopsy for cancer diagnosis and monitoring. However, sensitive and specific molecular detection and analysis are challenging, due to the small size of EVs, low amount of antigens on individual EVs, and the complex biofluid matrix. Nanomaterials have been widely used in the technological development of protein and nucleic acid-based EV detection and analysis, owing to the unique structure and functional properties of materials at the nanometer scale. In this review, we summarize various nanomaterial-based analytical technologies for molecular EV detection and analysis. We discuss these technologies based on the major types of nanomaterials, including plasmonic, fluorescent, magnetic, organic, carbon-based, and certain other nanostructures. For each type of nanomaterial, functional properties are briefly described, followed by the applications of the nanomaterials for EV biomarker detection, profiling, and analysis in terms of detection mechanisms.

A specific technique of immunolabelling of urinary small extracellular vesicle biomarkers for the diagnostic of renal cancer.

Small extracellular vesicles (EVs) are characterized by the membrane expression of CD63, CD81 and CD9 tetraspanins. Their size is inferior to 200 nm. They share the same characteristics as the native cells and are found in human fluids. Specific membrane protein biomarkers expressed on small EV are useful for the diagnosis of tumoural pathologies. Clear cell renal cell carcinoma (CCRCC) is diagnosed by imaging examinations and/or tissue biopsy. Carbonic anhydrase IX (CAIX) is a powerful biomarker of CCRCC. The detection of CAIX on small EV from the urine of patients could constitute a liquid biopsy for CCRCC. We have set up a specific protocol for the preparation, the immunostaining characterization and the transmission electron microscopy observation of small EVs isolated from the urine of CCRCC patients. The background labelling was significantly reduced. We successfully detected biomarkers on urinary small EVs from CCRCC patients. This technique could be extended with antibodies directed against other EV biomarkers for the detection and the monitoring of cancer diseases.

Acidification of blood plasma facilitates the separation and analysis of extracellular vesicles

BackgroundBlood plasma is available with minimal invasive sampling, it has significant diagnostic utility, and it is a valuable source of extracellular vesicles (EVs). Nevertheless, rich protein content, the presence of lipoproteins (LPs) that share similar biophysical properties, and relatively low abundance of EVs, especially those of rare subpopulations, make any downstream application a very challenging task. The growing evidence of the intricate surface interactome of EVs, and the association of EVs with LPs, impose further challenges during EV purification, detection, and biomarker analyses. ObjectivesIn this study, we tackled the fundamental issues of plasma EV yield and LP co-isolation and their implications in the subsequent marker analyses. MethodsModerate acidification of plasma was combined with size exclusion chromatography (SEC) and/or differential centrifugation (DC) to disrupt LPs and improve recovery of EVs and their subsequent detection by immunoassays and single-particle analysis methods. ResultsOur results demonstrate a surprisingly efficient enrichment of EVs (up to 3.3-fold higher than at pH 7) and partial depletion of LPs (up to 61.2%). Acidification of blood plasma samples enabled a quick single-step isoelectric precipitation of up to 20.4% of EVs directly from plasma, upon short low-speed centrifugation. ConclusionThus, acidification holds potential as a simple and inexpensive methodological step, which improves the efficacy of plasma EV enrichment and may have implications in future biomarker discoveries.