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The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles ("MISEV") guidelines for the field in 2014. We now update these "MISEV2014" guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points.

This article aims to document the growth in extracellular vesicle (EV) research. Here, we report the growth in EV-related studies, patents, and grants as well as emerging companies with major intent on exosomes. Four different databases were utilized for electronic searches of published literature: two general databases - Scopus/Elsevier and Web of Science (WoS), as well as two specialized US government databases - the USA Patent and Trademark Office and National Institutes of Health (NIH) of the Department of Health and Human Services. The applied combination of key words was carefully chosen to cover the most commonly used terms in titles of publications, patents and grants dealing with conceptual areas of EVs. Within the time frame from 1 January 2000 to 31 December 2016, limited to articles published in English, we identified output using search strategies based upon Scopus/Elsevier and WoS, patent filings and NIH Federal Reports of funded grants. Consistently, USA and UK universities are the most frequent among the top 15 affiliations/organizations of the authors of the identified records. There is clear evidence of upward streaming of EV-related publications. By documenting the growth of the EV field, we hope to encourage a roster of independent authorities skilled to provide peer review of manuscripts, evaluation of grant applications, support of foundation initiatives and corporate long-term planning. It is important to encourage EV research to further identify biomarkers in diseases and allow for the development of adequate diagnostic tools that could distinguish disease subpopulations and enable personalized treatment of patients., Competing Interests: Dr. Hochberg is President of CASCENT Inc. and TAVEC Inc (both exosome therapeutic companies without conflict).

We examined the extracellular vesicle (EV) and RNA composition of pooled normal cerebrospinal fluid (CSF) samples and CSF from five major neurological disorders: Alzheimer's disease (AD), Parkinson's disease (PD), low-grade glioma (LGG), glioblastoma multiforme (GBM), and subarachnoid haemorrhage (SAH), representing neurodegenerative disease, cancer, and severe acute brain injury. We evaluated: (I) size and quantity of EVs by nanoparticle tracking analysis (NTA) and vesicle flow cytometry (VFC), (II) RNA yield and purity using four RNA isolation kits, (III) replication of RNA yields within and between laboratories, and (IV) composition of total and EV RNAs by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and RNA sequencing (RNASeq). The CSF contained ~106 EVs/μL by NTA and VFC. Brain tumour and SAH CSF contained more EVs and RNA relative to normal, AD, and PD. RT-qPCR and RNASeq identified disease-related populations of microRNAs and messenger RNAs (mRNAs) relative to normal CSF, in both total and EV fractions. This work presents relevant measures selected to inform the design of subsequent replicative CSF studies. The range of neurological diseases highlights variations in total and EV RNA content due to disease or collection site, revealing critical considerations guiding the selection of appropriate approaches and controls for CSF studies.

Although the association between cancer and venous thromboembolism (VTE) has long been known, the mechanisms are poorly understood. Circulating tissue factor-bearing extracellular vesicles have been proposed as a possible explanation for the increased risk of VTE observed in some types of cancer. The International Society for Extracellular Vesicles (ISEV) and International Society on Thrombosis and Haemostasis (ISTH) held a joint Educational Day in April 2014 to discuss the latest developments in this field. This review discusses the themes of that event and the ISEV 2014 meeting that followed.

Background: The morphologic diagnosis of primary and metastatic intraocular lymphoma (IOL) was made difficult by the paucicellular specimens with fragile populations of lymphocytes retrieved through pars plana vitrectomy (PPV). The analysis of immunoglobulin heavy chain (IgH) gene rearrangements (AIGHR) was used as an adjunct to cytopathology and flow cytometry in systemic lymphoma. In IOL, the sensitivity and specificity of AIGHR are unknown., Methods: The authors reviewed the clinical records of patients who underwent PPV for suspicion of IOL at the Immunology and Uveitis Service of the Massachusetts Eye and Ear Infirmary (Boston, MA) between 2000 and 2002. AIGHR was performed as a routine diagnostic test on cell lysates isolated from < 0.5 mL of vitreous fluid. The authors used seminested polymerase chain reaction (PCR) with consensus primers for the VDJ-region of the IgH gene. PCR products were analyzed by polyacrylamide gel electrophoresis., Results: Thirty patients (37 specimens) with chronic vitritis and 17 patients (23 specimens) with IOL were included. The specificity of vitreous fluid cytopathology, flow cytometry, and AIGHR was 1.0, and the sensitivity values were 0.24, 0.36, and 0.64, respectively. AIGHR was negative in two patients for whom cytopathology or flow cytometry revealed the diagnosis of lymphoma. Clonal IGHR was found in four specimens classified as negative for lymphoma based on cytopathology and flow cytometry., Conclusions: AIGHR supplemented cytopathology and flow cytometry to increase the diagnostic yield in IOL., ((c) 2005 American Cancer Society.)

Brain lesions in inflammatory diseases may present as solitary masses, prompting a biopsy. We present neuroimaging and histologic findings in five patients with solitary, inflammatory, demyelinating mass lesions located in the supratentorial white matter and gray-white junction. The patients presented with seizures, focal neurologic signs, and neuroimaging findings that indicated the possibility of a neoplasm. Computed tomography (CT) revealed enhancing, single hypodense lesions associated with mild or no mass effect. On MRI, the lesions were hypointense on T1-weighted images and hyperintense on T2-weighted images. Variable patterns of enhancement were noted on CT and MRI, including homogeneous/patchy (n = 3) and ring/nodular (n = 1) enhancement. There was no evidence of calcification or hemorrhage. Biopsies revealed a leukoencephalitis and demyelination, with varying degrees of demyelination among the cases. The syndrome, relating to a solitary lesion, was corticosteroid-sensitive, and it ultimately stabilized. Extensive longitudinal evaluations failed to reveal multiple sclerosis, infection, or neoplasm. Solitary inflammatory lesions add to the differential diagnosis of large, supratentorial, solitary space-occupying lesions noted on CT and MRI scans.

Background: Paraneoplastic neurologic syndromes, although rare, cause significant morbidity and mortality. They are thought to be immunologically mediated, but to date those involving the central nervous system (CNS) have not been particularly responsive to immunologic therapy. The use of the novel immunomodulator, protein A immunoadsorption, was explored to address this question., Methods: Six patients with neurologic paraneoplastic syndromes were treated with this technique, using the "off line" method. Two hundred fifty ml of plasma was perfused through a column containing protein A covalently attached to a silica matrix. The plasma was then returned to the patient., Results: Five of the patients responded to the therapy, with complete and durable responses in three patients with opsoclonus-myoclonus, objective, though transient, improvement in one patient with paraneoplastic brainstem encephalitis associated with a Merkel cell tumor, and stabilization and partial improvement in one patient with paraneoplastic limbic encephalitis. The patient without response developed a cutaneous vasculitis after the second treatment, and therapy was discontinued., Conclusions: This therapy appears beneficial for a number of paraneoplastic syndromes, most dramatically in the opsoclonus/myoclonus syndrome.

Background: Primary central nervous system non-Hodgkin's lymphoma (NHL-CNS) is an enigmatic disease of uncertain origin. At the Massachusetts General Hospital, 104 patients with NHL-CNS were seen from 1958 through 1989. An impression of changes in the frequency of diagnosis, character of the tumors, and therapy for this disease prompted this study of the pathologic features, clinical data, and natural history of this tumor in these 104 patients., Methods: Histologic slides (neurosurgical specimens and autopsy tissues) were available for 99 patients. The tumors were classified by the Working Formulation classification. Immunostaining data and all clinical data were retrieved from the relevant offices and hospital charts., Results: Primary central nervous system non-Hodgkin's lymphoma tripled in frequency (5.66 cases per year in 1978-89 versus 1.75 cases per year in 1958-77) and now represents 6.6% of all primary brain neoplasms (versus 3.3% before 1978; chi 2 = 17.52, P < 0.01). For the 99 tumors histologically classified, 89% were high grade. Intermediate grade lymphomas, once the second most common subtype, have disappeared since 1983. All tumors had diffuse architecture; 77% (including all 11 patients with acquired immune deficiency syndrome) were large cell subtypes. Two cases were intravascular lymphoma. With one exception, all of the 41 tumors evaluated were B-cell types; 32 of 40 had monotypic surface immunoglobulin. There was 1 T-cell lymphoma. Of 64 tumor recurrences, 29 were at the initially defined site; 12 were in the leptomeninges, 29 were in other sites in the neuraxis, and 8 were in systemic sites. Systemic metastases have not occurred since 1984. Median survival for the 68 patients who survived after diagnostic surgery and for whom follow-up information could be obtained was 19 months; 9 months for those with high grade tumors and 30.5 months for those with intermediate grade tumors. This difference was not significant (P = 0.13). A separate set of seven patients had focal tumorlike lymphoid infiltrates composed of benign-appearing lymphocytes, which were associated with good long term survival. The differential histologic diagnosis of NHL-CNS was occasionally difficult, and the spectrum of this differential was broader than generally stated., Conclusions: Primary central nervous system non-Hodgkin's lymphoma has increased in frequency even in nonimunocompromised patient populations. This increase has been accompanied by the disappearance of intermediate grade histologic types, suggesting a fundamental shift in the biology of the neoplasms. The introduction of chemotherapeutic regimens appears to have altered the natural history such that systemic metastases outside the central nervous system no longer occur, and there are now some long term survivors of this formerly uniformly fatal disease.

Background: Intravascular lymphomatosis (IL) is a systemic neoplasm that often involves the nervous system, inducing progressive neurologic deficits in the setting of undiagnosed or quiescent extranodal non-Hodgkin lymphoma., Methods: The clinical and pathologic files of the Massachusetts General Hospital and New York University Medical Center and the English language literature were reviewed to identify all reports of intravascular lymphomatosis (angioendotheliomatosis) or other examples of a diffuse proliferation of neoplastic cells filling capillaries, arterioles, and venules., Results: The authors report seven patients with IL and note 114 patients reported in the literature. Almost two-thirds (63%) of patients had neurologic manifestations, without abnormalities on bone marrow biopsy, chest and abdominal tomographic examinations for adenopathy, and cerebrospinal fluid (CSF) analysis. All patients had one or more of four syndromes, each reflecting a vascular occlusive process: progressive, multifocal cerebrovascular events; paraparesis, pain, and incontinence; a subacute encephalopathy; and peripheral or cranial neuropathies., Conclusions: The unexplained presence of any one or more of these neurologic syndromes should alert the physician to the possible presence of this disease.

The clinical and pathologic data from two cases of medulloblastoma with systemic metastases, and 101 previously reported cases were evaluated to define better the clinical presentation and natural history. Patients ranged in age from six months to 48 years, with a mean of 13 years; two thirds of the patients were male. Ventricular shunts had been inserted in 20% of the patients. Systemic metastases occurred on an average of two years after the diagnosis of the primary tumor in patients without shunts, but only 1.3 years in patients with shunts. Fifty-nine percent of the patients were known to have experienced recurrence or spread of medulloblastoma within the central nervous system by the time systemic metastases appeared. Ninety percent showed radiologic evidence of bone metastases, of which 60% were osteoblastic. Bones most frequently involved were pelvis, femur and vertebrae; pain was the most common initial symptom. At autopsy, lymph node metastases were found in 65% and liver metastases were found in 28% of all cases in addition to bone metastases in 82%. Lung metastases occurred in 9% of the patients without shunts, compared with 30% of patients with shunts. The average survival was seven months after the appearance of systemic metastases for patients both with and without shunts. Approximately 5% of patients with medulloblastoma may be expected to develop systemic metastases. This development is associated with increased morbidity and a shortened life expectancy.