Number of microvesicles in peripheral blood and ability of plasma to induce adhesion between phospholipid membranes in 19 patients with gastrointestinal diseases

Concentration of extracellular vesicles isolated from blood relative to the clinical pathological status of dogs with mast cell tumours

Extracellular vesicles (EVs) are membrane-enclosed fragments shed from all cell types, including tumour cells. EVs contain a wide range of proteins, biolipids and genetic material derived from mother cells and therefore may be potential biomarkers for tumour diagnosis, disease progression and treatment success. We studied the effect of canine mast cell tumours (MCTs) on EV concentrations in blood isolates in association with MCT's histological grade, Ki-67 proliferative index, KIT-staining pattern and number of PLT. The average EV concentration in blood isolates from nine dogs with MCTs was considerably higher than that in blood from eight healthy dogs. But there were no statistically significant differences in EVs concentration in the population of dogs with MCT according to a different histological grade of malignancy (Patnaik, Kiupel), KIT-staining pattern and Ki-67 proliferation index. The results show that these variables statistically do not significantly predicted EV concentrations in blood isolates (P > .05), except the KIT-staining pattern I which added statistically significantly to the prediction (P < .05). The results confirmed the impact of neoplasms on the morphological changes to cell membranes, which result in greater vesiculability and higher EV concentrations.

Role of tumor‑derived extracellular vesicles in cancer progression and their clinical applications (Review)

Extracellular vesicles (EVs), including micro‑vesicles and exosomes, are heterogeneous small membranous vesicles shed from the surface of myriad cells and are crucial in mediating intercellular communication. The vertical trafficking of cargo to the plasma membrane and subsequent redistribution of surface lipids may contribute to EV formation. Tumor‑derived extracellular vesicles (TD‑EVs) can carry complex, bioactive cargo, such as nucleic acids and proteins, during tumor metastasis. Paracrine information gets relayed by TD‑EVs to adjacent tumor cells and this allows a crosstalk between malignant cells. These structures may even move to a distant metastatic lesion and modulate the tumor microenvironment to form a premetastatic niche. Thus, TD‑EVs might be potential biomarkers for tumor development and metastasis. Additionally, EVs are promising candidates for use as cell‑free vaccines or as vehicles for the delivery of specific tumor therapeutic molecules. Genetically modified microvesicles and engineered exosomes have shed light on a novel strategy for tumor‑targeted gene therapy. This review focuses on the role of EVs in tumor development and metastasis and their possible applications in the advanced diagnosis and therapy of cancer and personalized medicine.

Effect of shear stress in the flow through the sampling needle on concentration of nanovesicles isolated from blood

During harvesting of nanovesicles (NVs) from blood, blood cells and other particles in blood are exposed to mechanical forces which may cause activation of platelets, changes of membrane properties, cell deformation and shedding of membrane fragments. We report on the effect of shear forces imposed upon blood samples during the harvesting process, on the concentration of membrane nanovesicles in isolates from blood. Mathematical models of blood flow through the needle during sampling with vacuumtubes and with free flow were constructed, starting from the Navier-Stokes formalism. Blood was modeled as a Newtonian fluid. Work of the shear stress was calculated. In experiments, nanovesicles were isolated by repeated centrifugation (up to 17,570×g) and washing, and counted by flow cytometry. It was found that the concentration of nanovesicles in the isolates positively corresponded with the work by the shear forces in the flow of the sample through the needle. We have enhanced the effect of the shear forces by shaking the samples prior to isolation with glass beads. Imaging of isolates by scanning electron microscopy revealed closed globular structures of a similar size and shape as those obtained from unshaken plasma by repetitive centrifugation and washing. Furthermore, the sizes and shapes of NVs obtained by shaking erythrocytes corresponded to those isolated from shaken platelet-rich plasma and from unshaken platelet rich plasma, and not to those induced in erythrocytes by exogenously added amphiphiles. These results are in favor of the hypothesis that a significant pool of nanovesicles in blood isolates is created during their harvesting. The identity, shape, size and composition of NVs in isolates strongly depend on the technology of their harvesting.

CAS (CSE1L) signaling pathway in tumor progression and its potential as a biomarker and target for targeted therapy

CSE1L (chromosome segregation 1-like protein), also named as CAS (cellular apoptosis susceptibility protein), is highly expressed in most cancer types. CSE1L/CAS is a multiple functional protein that plays roles in apoptosis, cell survival, chromosome assembly, nucleocytoplasmic transport, microvesicle formation, and cancer metastasis; some of the functions are explicitly correlated. CSE1L is also a cancer serum biomarker. The phosphorylation of CAS is regulated by the extracellular signal-regulated kinase (ERK). The RAS/RAF/MAPK/ERK signaling pathways are the essential targets of most targeted cancer drugs, thus serum phosphorylated CSE1L may be a potential biomarker for monitoring drug resistance in targeted therapy. CSE1L can regulate Ras-induced ERK phosphorylation. CSE1L also regulates the expression and phosphorylation of CREB (cAMP response element binding protein) and MITF (microphthalmia-associated transcription factor) and is thus involved in the melanogenesis and progression of melanoma. CAS is an exosome/microvesicle membrane protein. Tumor cells consistently secrete microvesicles and tumor-derived microvesicles may be accumulated around tumors. Therefore, microvesicle membrane CSE1L may be a potential target for the development of high-efficacy antibody-drug conjugates (ADCs) for cancer therapy. This review will focus on CSE1L expression in cancers, its relationship to Ras/ERK and cAMP/PKA signaling pathways in melanoma development, its potential for the development of ADCs and tumor imaging reagents, and secretory phosphorylated CSE1L for monitoring the emergence of drug resistance in targeted cancer therapy.

Glioblastoma extracellular vesicles: reservoirs of potential biomarkers

Glioblastoma multiforme (GBM) is the most frequent and most devastating of the primary central nervous system tumors, with few patients living beyond 2 years postdiagnosis. The damage caused by the disease and our treatments for the patients often leave them physically and cognitively debilitated. Generally, GBMs appear after very short clinical histories and are discovered by imaging (using magnetic resonance imaging [MRI]), and the diagnosis is validated by pathology, following surgical resection. The treatment response and diagnosis of tumor recurrence are also tracked by MRI, but there are numerous problems encountered with these monitoring modalities, such as ambiguous interpretation and forms of pseudoprogression. Diagnostic, prognostic, and predictive biomarkers would be an immense boon in following treatment schemes and in determining recurrence, which often requires an invasive intracranial biopsy to verify imaging data. Extracellular vesicles (EVs) are stable, membrane-enclosed, virus-sized particles released from either the cell surface or from endosomal pathways that lead to the systemic release of EVs into accessible biofluids, such as serum/plasma, urine, cerebrospinal fluid, and saliva. EVs carry a wide variety of proteins, nucleic acids, lipids, and other metabolites, with many common features but with enough individuality to be able to identify the cell of origin of the vesicles. These components, if properly interrogated, could allow for the identification of tumor-derived EVs in biofluids, indicating tumor progression, relapse, or treatment failure. That knowledge would allow clinicians to continue with treatment regimens that were actually effective or to change course if the therapies were failing. Here, we review the features of GBM EVs, in terms of EV content and activities that may lead to the use of EVs as serially accessible biomarkers for diagnosis and treatment response in neuro-oncology.

Unfavorable hip stress distribution after Legg-Calvé-Perthes syndrome: a 25-year follow-up of 135 hips

To study the effect of hip and pelvis geometry on development of the hip after Perthes disease, we determined the resultant hip force and contact hip stress distribution in a population of 135 adult hips of patients who had been treated for Perthes disease in childhood. Contra-lateral hips with no record of disease were taken as the control population. Biomechanical parameters were determined by mathematical models for resultant hip force in one-legged stance and for contact hip stress, which use as an input the geometrical parameters assessed from anteroposterior radiographs. The mathematical model for stress was upgraded to account for the deviation of the femoral head shape from spherical. No differences were found in resultant hip force and in peak contact hip stress between the hips that were in childhood subject to Perthes disease and the control population, but a considerable (148%) and significant (p < 0.001) difference was found in the contact hip stress gradient index, expressing an unfavorable, steep decrease of contact stress at the lateral acetabular rim. This finding indicates an increased risk of early coxarthritis in hips subject to Perthes disease.

The role of extracellular vesicles in phenotypic cancer transformation

Background

Cancer has traditionally been considered as a disease resulting from gene mutations. New findings in biology are challenging gene-centered explanations of cancer progression and redirecting them to the non-genetic origins of tumorigenicity. It has become clear that intercellular communication plays a crucial role in cancer progression. Among the most intriguing ways of intercellular communication is that via extracellular vesicles (EVs). EVs are membrane structures released from various types of cells. After separation from the mother membrane, EVs become mobile and may travel from the extracellular space to blood and other body fluids.

Conclusions

Recently it has been shown that tumour cells are particularly prone to vesiculation and that tumour-derived EVs can carry proteins, lipids and nucleic acids causative of cancer progression. The uptake of tumour-derived EVs by noncancerous cells can change their normal phenotype to cancerous. The suppression of vesiculation could slow down tumour growth and the spread of metastases. The purpose of this review is to highlight examples of EV-mediated cancer phenotypic transformation in the light of possible therapeutic applications.

A 32-month follow-up study of nanovesicle concentrations in blood from 12 patients with gastrointestinal stromal tumour treated with imatinib

Clinical studies have indicated that the NV (nanovesicle) concentration in blood samples is a potential indicator of clinical status and can be used to follow the development of the disease. For 32 months, we monitored the effect of imatinib treatment on NV concentrations in blood samples from 12 patients with GIST (gastrointestinal stromal tumour). The NV concentration before the treatment increased with respect to control by a factor of 3.5 on average (range 2.6–9.2). The first week after initiation of the treatment, the NV concentration increased considerably, by a factor of 13 on average (range 5.9–21.2), whereas on average, after 1 month, it decreased to the level of the control and remained at that level for at least 1.5 years. Recent assessment (after 2.5 years) showed a somewhat increased NV concentration, by a factor of 2 on average (range 0.7–3.9). Low NV concentrations in blood samples during the treatment reflect a favourable effect of imatinib in these patients and no remission of the disease was hitherto observed.

Effect of engineered TiO2 and ZnO nanoparticles on erythrocytes, platelet-rich plasma and giant unilamelar phospholipid vesicles

Background

Massive industrial production of engineered nanoparticles poses questions about health risks to living beings. In order to understand the underlying mechanisms, we studied the effects of TiO₂ and ZnO agglomerated engineered nanoparticles (EPs) on erythrocytes, platelet-rich plasma and on suspensions of giant unilamelar phospholipid vesicles.

Results

Washed erythrocytes, platelet-rich plasma and suspensions of giant unilamelar phospholipid vesicles were incubated with samples of EPs. These samples were observed by different microscopic techniques. We found that TiO₂ and ZnO EPs adhered to the membrane of washed human and canine erythrocytes. TiO₂ and ZnO EPs induced coalescence of human erythrocytes. Addition of TiO₂ and ZnO EPs to platelet-rich plasma caused activation of human platelets after 24 hours and 3 hours, respectively, while in canine erythrocytes, activation of platelets due to ZnO EPs occurred already after 1 hour. To assess the effect of EPs on a representative sample of giant unilamelar phospholipid vesicles, analysis of the recorded populations was improved by applying the principles of statistical physics. TiO₂ EPs did not induce any notable effect on giant unilamelar phospholipid vesicles within 50 minutes of incubation, while ZnO EPs induced a decrease in the number of giant unilamelar phospholipid vesicles that was statistically significant (p < 0,001) already after 20 minutes of incubation.

Conclusions

These results indicate that TiO₂ and ZnO EPs cause erythrocyte aggregation and could be potentially prothrombogenic, while ZnO could also cause membrane rupture.

Stability of membranous nanostructures: a possible key mechanism in cancer progression

Membranous nanostructures, such as nanovesicles and nanotubules, are an important pool of biological membranes. Recent results indicate that they constitute cell-cell communication systems and that cancer development is influenced by these systems. Nanovesicles that are pinched off from cancer cells can move within the circulation and interact with distant cells. It has been suggested and indicated by experimental evidence that nanovesicles can induce metastases from the primary tumor in this way. Therefore, it is of importance to understand better the mechanisms of membrane budding and vesiculation. Here, a theoretical description is presented concerning consistently related lateral membrane composition, orientational ordering of membrane constituents, and a stable shape of nanovesicles and nanotubules. It is shown that the character of stable nanostructures reflects the composition of the membrane and the intrinsic shape of its constituents. An extension of the fluid mosaic model of biological membranes is suggested by taking into account curvature-mediated orientational ordering of the membrane constituents on strongly anisotropically curved regions. Based on experimental data for artificial membranes, a possible antimetastatic effect of plasma constituents via mediation of attractive interaction between membranous structures is suggested. This mediated attractive interaction hypothetically suppresses nanovesiculation by causing adhesion of buds to the mother membrane and preventing them from being pinched off from the membrane.

Determination of the strength of adhesion between lipid vesicles

A commonly used method to determine the strength of adhesion between adhering lipid vesicles is measuring their effective contact angle from experimental images. The aim of this paper is to estimate the interobserver variations in vesicles effective contact angle measurements and to propose a new method for estimating the strength of membrane vesicle adhesion. Theoretical model shows for the old and for the new measure a monotonic dependence on the strength of adhesion. Results obtained by both measuring techniques show statistically significant correlation and high interobserver reliability for both methods. Therefore the conventional method of measuring the effective contact angle gives qualitatively relevant results as the measure of the lipid vesicle adhesion. However, the new measuring technique provides a lower variation of the measured values than the conventional measures using the effective contact angle. Moreover, obtaining the adhesion angle can be automatized more easily than obtaining the effective contact angle.

Nanoparticles isolated from blood: a reflection of vesiculability of blood cells during the isolation process

BACKGROUND

Shedding of nanoparticles from the cell membrane is a common process in all cells. These nanoparticles are present in body fluids and can be harvested by isolation. To collect circulating nanoparticles from blood, a standard procedure consisting of repeated centrifugation and washing is applied to the blood samples. Nanoparticles can also be shed from blood cells during the isolation process, so it is unclear whether nanoparticles found in the isolated material are present in blood at sampling or if are they created from the blood cells during the isolation process. We addressed this question by determination of the morphology and identity of nanoparticles harvested from blood.

METHODS

The isolates were visualized by scanning electron microscopy, analyzed by flow cytometry, and nanoparticle shapes were determined theoretically.

RESULTS

The average size of nanoparticles was about 300 nm, and numerous residual blood cells were found in the isolates. The shapes of nanoparticles corresponded to the theoretical shapes obtained by minimization of the membrane free energy, indicating that these nanoparticles can be identified as vesicles. The concentration and size of nanoparticles in blood isolates was sensitive to the temperature during isolation. We demonstrated that at lower temperatures, the nanoparticle concentration was higher, while the nanoparticles were on average smaller.

CONCLUSION

These results indicate that a large pool of nanoparticles is produced after blood sampling. The shapes of deformed blood cells found in the isolates indicate how fragmentation of blood cells may take place. The results show that the contents of isolates reflect the properties of blood cells and their interaction with the surrounding solution (rather than representing only nanoparticles present in blood at sampling) which differ in different diseases and may therefore present a relevant clinical parameter.

Circulating tumour-derived microvesicles in plasma of gastric cancer patients

Cell membrane microfragments called microvesicles (MV) originating from different cells are circulating in the blood of healthy subjects and their elevated numbers are found in different diseases, including cancer. This study was designed to characterise MV present in plasma of gastric cancer patients. Since majority of MV in blood are platelets-derived (PMV), plasma samples deprived of PMV were used. In comparison to control, the number of MV in patients was significantly elevated in all stages, higher in more advanced disease. Patients' MV showed an increased membrane expression of CCR6 and HER-2/neu. The proportion of MV carrying some leucocyte determinants was low and similar in patients and control. Transmission electron microscopy showed their substantial heterogeneity in size and shape. The size determined by dynamic light scattering analysis confirmed this heterogeneity. The MV size distribution in patients was broader within the range of 10-800 nm, while in control MV showed 3-mode distribution within the range of 10-400 nm. Atomic force microscopy confirmed MV size heterogeneity with implication that larger objects represented aggregates of smaller microparticles. Patients' MV exhibited increased absolute values of zeta potential, indicating a higher surface charge. Tumour markers HER-2/neu, MAGE-1, c-MET and EMMPRIN were detected both in control and patients' samples with stronger expression in the latter. Significantly higher expression of MAGE-1 and HER-2/neu mRNA was observed in individual patients. All together, it suggests that at least some MV in plasma of gastric cancer patients are tumour-derived. However, their role in cancer requires further studies.

Isolated microvesicles from peripheral blood and body fluids as observed by scanning electron microscope

Microvesicles are sub-micron structures shed from the cell membrane in a final step of the budding process. After being released into the microenvironment they are free to move and carry signaling molecules to distant cells, thereby they represent a communication system within the body. Since all cells shed microvesicles, it can be expected that they will be found in different body fluids. The potential diagnostic value of microvesicles has been suggested, however, a standardized protocol for isolation has not yet been agreed upon. It is unclear what is the content of the isolates and whether the isolated microvesicles were present in vivo or-have they been created within the isolation procedure. To present evidence in this direction, in this work we focus on the visualization of the material obtained by the microvesicle isolation procedure. We present scanning electronic microscope images of microvesicles isolated from blood, ascites, pleural fluid, cerebrospinal fluid, postoperative drainage fluid and chyloid fluid acquired from human and animal patients. Vesicular structures sized from 1microm downto 50nm are present in isolates of all considered body fluids, however, the populations differ in size and shape reflecting also the composition of the corresponding sediments. Isolates of microvesicles contain numerous cells which indicates that methods of isolation and determination of the number of microvesicles in the peripheral blood are to be elaborated and improved.

Mechanisms for the formation of membranous nanostructures in cell-to-cell communication

Cells interact by exchanging material and information. Two methods of cell-to-cell communication are by means of microvesicles and by means of nanotubes. Both microvesicles and nanotubes derive from the cell membrane and are able to transport the contents of the inner solution. In this review, we describe two physical mechanisms involved in the formation of microvesicles and nanotubes: curvature-mediated lateral redistribution of membrane components with the formation of membrane nanodomains; and plasmamediated attractive forces between membranes. These mechanisms are clinically relevant since they can be affected by drugs. In particular, the underlying mechanism of heparin's role as an anticoagulant and tumor suppressor is the suppression of microvesicluation due to plasma-mediated attractive interaction between membranes.