Concentration Of Microparticles Research Articles

Magnetic impedance of film nanostructures for stray magnetic field evaluation of microparticles in magnetic composites

Longitudinal giant magnetoimpedance effect of [Fe21Ni79/Cu]5/Cu/[Fe21Ni79/Cu]5 film element was investigated depends on stray magnetic field of epoxy magnetic composite with 30% weight concentration of iron oxide magnetic microparticles. Configuration of an experiment was a model of thrombus detection in a blood vessel. Stray magnetic field was varied by movement of a magnetic composite above the element perpendicular to the long side. Composite was either magnetized or not to the state of remanence. As the magnetic composite approaches the GMI element, MI ratio curves are smoothed and shifted along the field axis and maximum value of the MI ratio decreases. Magnetic properties of magnetic composite and film element were investigated as well. Keywords: Magnetoimpedance effect, multilayered film nanostructures, composite materials, biodetection.

Static puncture resistance characteristics with various indenter nose shape geometry perforation of shear thickening fluid impregnated polypropylene fabric for soft armour application

At present, puncture resistance and rheological performance of shear thickening fluid (STF) is an essential design requirement for a soft armour material (target sample). The target sample is prepared with a dip and dry process of STF impregnated woven polypropylene (PP) fabric. These samples were tested and compared with neat PP fabric. The penetration depth of target samples is highly sensitive to the coefficient of friction between the indenter’s nose shape geometry and the target sample. The STF is prepared by mechanical dispersion of synthesized microsphere silica microparticles at a volume fraction of 57% in polyethylene glycol (400 g/mol). The rheological response indicates that the prepared concentration of silica microparticles in the STF suspension is observed to have a better shear thickening effect. The viscosity of suspension is highly sensitive to silica aspect ratio, volume fraction and particle size distribution in this work. Tensile tests along with puncture resistance with different indenter nose shapes geometry (hemispherical, elliptical, flat and conical) have been performed in the present study. Results indicate that the energy absorption is more with the hemispherical indenter and less with that of the conical indenter, which is attributed to the minimum surface area of contact as compared to all other indenters. A total of 16 number of fabricated target samples with various coating thicknesses of STF impregnated fabrics achieved the desired tensile strength, modulus and puncture resistance.

Microfluidic acoustic sawtooth metasurfaces for patterning and separation using traveling surface acoustic waves.

We demonstrate a sawtooth-based metasurface approach for flexibly orienting acoustic fields in a microfluidic device driven by surface acoustic waves (SAW), where sub-wavelength channel features can be used to arbitrarily steer acoustic fringes in a microchannel. Compared to other acoustofluidic methods, only a single travelling wave is used, the fluidic pressure field is decoupled from the fluid domain's shape, and steerable pressure fields are a function of a simply constructed polydimethylsiloxane (PDMS) metasurface shape. Our results are relevant to microfluidic applications including the patterning, concentration, focusing, and separation of microparticles and cells.

300 PCSK9 induces a prothrombotic response by activation of NFKB signalling pathway in mononuclear cells

Abstract Aims Strong evidence both experimental and clinical studies point out to an involvement of proprotein convertase subtilisin/kexin 9 (PCSK9), as an important player in hypercholesterolemia and atherosclerosis pathophysiology, identifying it, as a key molecule in the development of new cholesterol-lowering drugs and therapeutic target for atherosclerosis and related diseases. Emerging evidence shown that PCSK9 is straight implicated in inflammatory process where it may directly influence the activity of various cell types through NFkB activation, a key transcription factor involved in the induction of both pro-inflammatory cytokines and Tissue Factor (TF) expression, a major regulator of haemostasis and thrombosis in monocytes. Deductive reasoning makes therefore plausible to investigate a mechanistic link between circulation PCSK9 levels and TF expression, both in monocytes as well as on the surface of microparticles (MPs) generated from the same cells, with NFkB acting as the chain in the link. To investigate the involvement of NFkB signalling pathway in PCSK9-induced TF expression. Methods THP-1 cell line were stimulated with human (h) PCSK9 (5 μg/mL) or pre-incubated with BAY-117082 (BAY, 10−5M) an NFκB inhibitor, CLI-095 (3 × 10−6M), a highly TLR-4 signalling specific inhibitor and LPS-RS(5 μg/mL) a TLR-4 antagonist. TF procoagulant activity (PCA) was assessed by one-stage clotting assay using a STart Max semi-automated coagulation analyser. Concentration of TF-bearing MPs was determined using the Zymuphen MP-activity kit. Results hPCSK9 stimulated TF activity in THP-1 (PCA: from 50 ± 20 to 120 ± 20 ρg/mL, n = 10, P < 0.01). BAY, an NFkB inhibitor (PCA: −71 ± 23%, n = 5, P < 0.01) and CLI-095, a TLR-4 signalling inhibitor, (PCA: −86 ± 26%, n = 3, P < 0.05) and LPS-RS (PCA: −71 ± 23%, n = 5, P < 0.01) down-regulated PCSK9-induced TF activity completely. Furthermore THP-1stimulation with hPCSK9 causes the release of prothrombotic MPs-TF+ (MPs release from: 0.13 ± 0.07 to 0.42 ± 0.1 nM PS, n = 7, P < 0.05; PCA-MP+ from: 14 ± 3 to 44 ± 28 ρg/mL, n = 5, P < 0.05). Conclusions These data confirm the pivotal role of monocytes in the response PCSK9-induced TF-expression as well as the involvement of PCSK9 in inflammatory-thrombotic diseases through a direct stimulation of TF procoagulant activity and by the release of TF-bearing MPs. The possible mechanism of action involves recognition of PCSK9 by TLRs 2 and/or 4, on monocytes membrane surface, leading to activation of the transcription factor NFκB via an intracellular signalling cascade. Further studies will be needed to better understand the regulatory mechanisms underlying this complex set of biological responses that bind PCSK9, and coagulation events.

Intradialytic cycling does not exacerbate microparticles or circulating markers of systemic inflammation in haemodialysis patients

PurposePatients receiving haemodialysis (HD) display elevated circulating microparticle (MP) concentration, tissue factor (TF) expression and markers of systemic inflammation, though regular intradialytic cycling (IDC) may have a therapeutic effect. This study investigated the impact of regular, moderate-intensity IDC on circulating MPs and inflammatory markers in unit-based HD patients.MethodsPatients were cluster-randomised to intervention (n = 20, age: 51.4 ± 18.1 years, body mass: 77.6 ± 18.3 kg, mean ± SD) or no-exercise control (n = 20, 56.8 ± 14.0 years, 80.5 ± 26.5 kg). Intervention participants completed 30 min of moderate intensity (rating of perceived exertion [RPE] of 12–14) IDC, thrice weekly for 6 months. Pre-dialysis venous blood samples were obtained at 0, 3 and 6 months. Circulating MP phenotypes, cytokines, chemokine and MP TF expression were quantified using flow cytometry and cytometric bead array assays.ResultsDespite high exercise compliance (82%), no IDC-dependent effects were observed for any MP, cytokine or chemokine measure (p ≥ 0.051, ηρ2 ≤ 0.399) other than TNF-α (p = 0.001, ηρ2 = 0.186), though no significance was revealed upon post hoc analysis.ConclusionSix months of regular, moderate-intensity IDC had no effect on MPs, cytokines or chemokines. This suggests that the exercise did not exacerbate thrombotic or inflammatory status, though further functional assays are required to confirm this.Trial registrationISRCTN1129707, prospectively registered on 05/03/2015.

Meteorological and climatic variability influences anthropogenic microparticle content in the stomach of the European anchovy Engraulis encrasicolus

Meteorological and climatic phenomena affect oceanographic characteristics and, consequently, anthropogenic microparticle aggregation. The same phenomena influence the ecology of pelagic fish, but whether there is a connection between meteorological and climatic characteristics and microparticle ingestion remains unknown. In the NW Mediterranean during the springs of 2011–2014, the incidence of contaminated European anchovies (35 ± 17%) and microparticle abundance in the stomach content (0.46 ± 0.25 microparticles ind−1) may have owed to higher concentrations of microparticles due to hydrodynamism. Year 2011 showed a higher fragment contribution (60 ± 17%). The statistical analysis indicated a link between fragment abundance and climatic characteristics, with low North Atlantic Oscillation index values for the previous cold season indicating the transport of water from the polluted Tyrrhenian Sea. Low-density microplastic (polyethylene and polypropylene) was found, a selection due to the pelagic behaviour of anchovy. Fibre abundance remained quite constant throughout the 4-year period, pointing to diffused input not dependent on meteorological forcing. In 2012, anchovies were subjected to bottom-up limitation, due to adverse meteorological forcing (high early spring temperatures, low rainfall). The anchovies mainly ingested fibres through less energy-expensive filter-feeding. Therefore, meteorological and climatic forcing regulates microparticle intake by fish and should be considered for pollution mitigation.

Assessment of the Effects of Environmental Concentrations of Microplastics on the Aquatic Snail Potamopyrgus antipodarum

Microplastics are ubiquitous in aquatic ecosystems. They can be found at the surface, in the water column, and in sediments. Multiple negative impacts of microplastics on aquatic organisms have been reported, with most studies focusing on marine ecosystems. However, the effects of microplastics on freshwater ecosystems have been less studied, with a few studies focusing on benthic invertebrates. In this study, we exposed the New Zealand mud snail Potamopyrgus antipodarum (Gray, 1843) to an environmental range of concentrations of polystyrene microparticles (size range from 0.01 to 514 µm at 100, 500, and 1000 mg microplastics/kg dry weight (dw) of sediment) and two supra-environmental concentrations (2000 and 4000 mg/kg dw sediment). The impacts of the exposure to microplastics on mortality, behavior, and reproduction were assessed at long-term exposure (31 days). Mortality and reproduction were not significantly affected by microplastics. On the contrary, most of the microplastic treatments altered the behavior, causing a significant increase in reaction time compared with controls (0 mg microplastics/kg dw sediment). The highest concentration (4000 mg/kg) did not have an impact on the reaction time over the experimental period compared with controls. To our knowledge, this study is the first to assess the effects of microplastics on the behavior of the aquatic snail P. antipodarum. Our results showed that at environmental concentrations, the behavior of P. antipodarum was the most sensitive variable to the adverse effects of polystyrene microplastics.

Convection in an evaporating drop of aqueous solution at a high concentration of microscopic particles

This article presents the performed experimental studies on the effect of the concentration of microparticles on free convection in a water drop located on a heated smooth and textured wall surface. It is shown that at a high concentration of particles, their aggregation and deposition take place on the wall and on the free surface of droplet. As a result, the average convection velocity in the droplet decreases significantly. Suppression of convection is important to consider when simulating heat transfer and droplet evaporation. The results obtained are important for technologies that use colloidal solutions (drops, films).

Temporal Variability of Microparticles Under the Seattle Aquarium, Washington State: Documenting the Global Covid-19 Pandemic.

Anthropogenic debris including microparticles (<5 mm) are ubiquitous in marine environments. The Salish Sea experiences seasonal fluctuations in precipitation, river discharge, sewage overflow events, and tourism—all variables previously thought to have an impact on microparticle transport and concentrations. Our goals are two‐fold: 1) describe long‐term microparticle contamination data including concentration, type, and size; and 2) determine if seasonal microparticle concentrations are dependent on environmental or tourism variables in Elliott Bay, Salish Sea. We sampled 100 L of seawater at a depth of approximately 9 m at the Seattle Aquarium, Seattle, Washington State, United States, approximately every two weeks from 2019 through 2020 and used an oil extraction protocol to separate microparticles. We found that microparticle concentrations ranged from 0 to 0.64 particles L−1 and fibers were the most common type observed. Microparticle concentrations exhibited a breakpoint on 10 April 2020, where estimated slope and associated microparticle concentration significantly declined. Further, when considering both environmental as well as tourism variables, temporal microparticle concentration was best described by a mixed‐effects model, with tourism as the fixed effect and the person counting microparticles as the random effect. Although monitoring efforts presented set out to identify effects of seasonality and interannual differences in microparticle concentrations, it instead captured an effect of decreased tourism due to the global Covid‐19 pandemic. Long‐term monitoring is critical to establish temporal microparticle concentrations and to help researchers understand if there are certain events, both seasonal and sporadic (e.g., rain events, tourism, or global pandemics), when the marine environment is more at risk from anthropogenic pollution. Environ Toxicol Chem 2022;41:917–930. © 2021 Seattle Aquarium. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Rivaroxaban compared with low-dose aspirin in individuals with type 2 diabetes and high cardiovascular risk: a randomised trial to assess effects on endothelial function, platelet activation and vascular biomarkers

Aims/hypothesisIndividuals with type 2 diabetes mellitus and subclinical inflammation have stimulated coagulation, activated platelets and endothelial dysfunction. Recent studies with the direct factor Xa inhibitor rivaroxaban in combination with low-dose aspirin demonstrated a significant reduction of major cardiovascular events, especially in individuals with type 2 diabetes and proven cardiovascular disease. Therefore, we asked the question of whether treatment with rivaroxaban could influence endothelial function, arterial stiffness and platelet activation.MethodsWe conducted a multi-centre, prospective, randomised, open-label trial in 179 participants with type 2 diabetes (duration 2–20 years), subclinical inflammation (high-sensitivity C-reactive protein 2–10 mg/l) and at least two traits of the metabolic syndrome to compare the effects of the direct factor Xa inhibitor rivaroxaban (5 mg twice daily) vs aspirin (100 mg every day) on endothelial function (assessed by forearm occlusion plethysmography), skin blood flow (assessed by laser-Doppler fluxmetry), arterial stiffness (assessed by pulse wave velocity) and serum biomarkers of endothelial function and inflammation. Furthermore, we investigated phosphorylation of vasodilator-stimulated phosphoprotein (VASP) in platelets, the concentration of platelet-derived microparticles (PMPs) and the effects of isolated PMPs on HUVEC proliferation in vitro.ResultsRivaroxaban treatment for 20 weeks (n = 89) resulted in a significant improvement of post-ischaemic forearm blood flow (3.6 ± 4.7 vs 1.0 ± 5.2 ml/100 ml, p = 0.004), a numerically increased skin blood flow and reduced soluble P-Selectin plasma level vs aspirin. We did not find significant differences of arterial stiffness or further biomarkers. Neither rivaroxaban nor aspirin influenced VASP phosphorylation of platelets. The number of PMPs increased significantly with both rivaroxaban (365.2 ± 372.1 vs 237.4 ± 157.1 μl−1, p = 0.005) and aspirin (266.0 ± 212.7 vs 201.7 ± 162.7 μl−1, p = 0.021). PMPs of rivaroxaban-treated participants stimulated HUVEC proliferation in vitro compared with aspirin. Rivaroxaban was associated with a higher number of bleeding events.Conclusions/interpretationOur findings indicate that the direct factor Xa inhibitor rivaroxaban improved endothelial function in participants with type 2 diabetes and subclinical inflammation but also increased the risk of bleeding.Trial registration:ClinicalTrials.gov NCT02164578.FundingThe study was supported by a research grant from Bayer Vital AG, Germany.Graphical abstract

Positive Association between Endothelium-Platelet Microparticles and Urinary Concentration of Lead and Cadmium in Adolescents and Young Adults.

(1) Background: In previous research, higher levels of urine heavy metals, especially lead and cadmium, have been associated with increased cardiovascular risk. However, there is no information linking exposure to heavy metal to endothelial and platelet microparticles (EMPs and PMPs), particularly in the younger population, which are novel biomarkers of endothelial dysfunction. (2) Methods: From a nationwide database, which was incepted in 1992–2000, screening for renal health among Taiwanese school children, a total of 789 subjects were recruited. Cross-sectional analysis was performed to evaluate the association between serum EMPs/PMPs and urine iron, nickel, copper, cadmium, lead, chromium, manganese, and zinc levels in the adolescent and young adult population. (3) Results: After we adjusted the conventional cardiovascular risk factors, CD31+/CD42a− and CD31+/CD42a+ counts, in subjects’ serum, respective markers of EMP and PMP displayed a significant positive dose-response relationship with urinary lead and cadmium levels. Higher quartiles of urine lead and cadmium levels were associated with an increased risk of higher EMPs/PMPs (≥75th percentile) in a multivariate logistic regression model. (4) Conclusion: Higher urinary lead and cadmium concentrations are strongly associated with endothelium–platelet microparticles in this adolescent and young adult population, which could help explain, in part, the mechanism through which heavy metal exposure results in cardiotoxicity.

Apoptotic microparticles mediate the association between bisphenol A and subclinical atherosclerosis in a young population: A population-based study

Bisphenol A (BPA) exposure is associated with atherosclerotic cardiovascular diseases. The interactions between BPA, extracellular microparticles (MPs), and atherosclerosis are unknown. A total of 103,756 young students participated in the mass urine-screening program in Taiwan between 1992 and 2000 were analyzed. After exclusion, 886 subjects were recruited to test the relationships between serum level of BPA, endothelial and platelet MPs as well as subclinical atherosclerosis represented by carotid artery intima-media thickness (CIMT). We found that an increment of one unit of log-BPA could lead to significant association between thicker CIMT and concentrations of endothelial microparticles and platelet microparticles in the cohort (odds ratio (OR) 1.23, P < 0.001). CD31 + /CD42a- (> 50%, OR 1.229, P = 0.001) and CD31 + /CD42a+ (≦ 50%, OR 1.262, P = 0.017 and > 50%, OR 1.212, P = 0.006) were significantly associated with thicker CIMT in the presence of elevated BPA. When considering the interactions between CD31 + /CD42a- and CD31 + /CD42a+ , we observed increased OR as CD31 + /CD42a- was greater than 50% (CD31 +/CD42a- > 50% and CD31 +/CD42a+ ≦ 50%, OR 1.356, P = 0.029; CD31 +/CD42a- > 50% and CD31 +/CD42a+ > 50%, OR 1.204, P = 0.014). Our study identified a higher risk of thicker CIMT associated with altered MPs in the presence of elevated BPA levels. BPA exposure is associated with endothelial dysfunction and subclinical atherosclerosis in a young population.

A hydrogel/particle composite with a gradient of oxygen releasing microparticle for concurrent osteogenic and chondrogenic differentiation in a single scaffold

In the present study, a hydrogel/particle scaffold with a gradient of the oxygen releasing microparticles was developed. Hydrogel component was composed of the oxidized pectin and silk fibroin, whereas the microparticles were constituted from polylactic acid (PLA) and calcium peroxide (CPO). A controlled mixing of the suspensions with different content of the PLA/CPO microparticles conferred a gradient of microparticles in scaffold thickness in a manner that the microparticle content increased with moving from lower to upper face of the composite. Measurement of the scaffold mechanical properties corroborated that with moving from lower to upper face, the compressive modulus increased by 78 %. The measurement of the oxygen and calcium release from the successive sections of the composite revealed that the gradient of microparticle concentration resulted in the gradient of the released oxygen and calcium. MTT analysis proved that the gradient oxygen releasing composite did not induce any toxic effect on human adipose-derived mesenchymal stem cells (hAd-MSCs). Moreover, the cell culture on successive sections of the gradient composite confirmed that oxygen releasing composite substantially improved the cell viability and density comparing the pristine hydrogel and the non-oxygen releasing counterpart. The increase in microparticle content conferred a positive impact on the number of viable cells. The study of osteogenic (ALP, OCN and OPN) and chondrogenic (SOX9, AGG and COL ⅠⅠ) gene expression proved that the gradient composite parts with high microparticle content promoted osteogenesis, whereas the parts with low microparticle content encouraged chondrogenesis of mesenchymal stem cells.

A room-temperature operable and stretchable NO2 gas sensor composed of reduced graphene oxide anchored with MOF-derived ZnFe2O4 hollow octahedron

Stretchable and highly sensitive gas sensors are currently receiving great attention due to their pertinence in wearable technology for detecting environmental conditions as well as for human safety. Herein, room-temperature operable, stretchable, highly selective, and stable gas sensors were engineered by decorating networked reduced graphene oxide (rGO) with metal-organic framework-derived zinc ferrite (ZnFe2O4) microparticles on a three-dimensionally micropatterned stretchable polydimethylsiloxane substrate which is mountable on human skin for possible e-skin applications. The effect of mesoporous ZnFe2O4 microparticles concentration on gas sensing performance was investigated. Due to the existence of high-density defect sites in the mesoporous microparticles, the introduction of ZnFe2O4 in the rGO-based chemiresistive sensor demonstrated fast detection performance for nitrogen dioxide (NO2) across a wide range from 50 to 4,000 ppb with improved sensitivity (219.44 % ppm−1) and lower limit of detection (1.49 × 10-4 ppm) compared to the pristine rGO-based sensor. The rGO-ZnFe2O4-based gas sensor showed good reproducibility and stable dynamic responses under application of static and dynamic stretching as well as workability in high humidity (up to 80 %) conditions even in the low concentration range (from 50 to 250 ppb) of NO2. These beneficial features of the stretchable gas sensors demonstrate their excellent potential for wearable gas sensing technology applications.

Ultraviolet germicidal irradiation of melted snow and ice samples: inactivation of microorganisms and effects on insoluble microparticles

AbstractThe long-term refrigerated storage of melted snow and/or ice samples for analyses of insoluble microparticles (hereafter, microparticles) may be limited by increases in the biological particle concentration caused by microbial growth after ~1–2 weeks. In this study, we examined an ultraviolet (UV) disinfection method for the storage of melted snow and/or ice samples and determined the effects of this method on microparticles. Surface snow obtained from Glacier No. 31 in the Suntar-Khayata Range, eastern Siberia, Russia was divided into two portions for UV treatment and untreated controls. Microparticle concentrations and size distributions (in the range of 0.52–12.0 μm) in the samples were measured using a Coulter counter. Whereas the microparticle concentration in untreated samples increased, no obvious increase was observed over 53 d in the samples subjected to UV treatment. Microbial growth was detected in only untreated samples using a viable particle counter. In addition, the original microparticle concentrations and size distributions were unaffected by UV treatment. Our results demonstrated that the microparticle size distribution in untreated melted water samples reflects the growth, decomposition and succession of microorganisms over time and further indicate that UV irradiation is effective for long-term storage for microparticle analysis.

Microplastic contamination in Great Lakes fish.

Freshwater ecosystems, generally adjacent to human population and more contaminated relative to adjacent marine ecosystems, are vulnerable to microplastic contamination. We sampled 7 species of fish from Lake Ontario and Lake Superior and assessed their gastrointestinal (GI) tracts to quantify ingested microplastics and other anthropogenic particles. A subset of the microparticles were chemically analyzed to confirm polymer types and anthropogenic origins. We documented the highest concentration of microplastics and other anthropogenic microparticles ever reported in bony fish. We found 12,442 anthropogenic microparticles across 212 fish (8 species) from nearshore Lake Ontario, 943 across 50 fish (1 species) from Humber River, and 3094 across 119 fish (7 species) from Lake Superior. Fish from Lake Ontario had the greatest mean abundance of anthropogenic microparticles in their GI tracts (59 particles/fish [SD 104]), with up to 915 microparticles in a single fish. Fish from Lake Superior contained a mean [SD] of 26 [74] particles/fish, and fish from Humber River contained 19 [14] particles/fish. Most particles were microfibers. Overall, ≥90% of particles were anthropogenic, of which 35-59% were microplastics. Polyethylene (24%), polyethylene terephthalate (20%), and polypropylene (18%) were the most common microplastics. Ingestion of anthropogenic particles was significantly different among species within Lake Ontario (p < 0.05), and the abundance of anthropogenic particles increased as fish length increased in Lake Ontario (ρ = 0.62). Although we cannot extrapolate the concentration of microplastics in the water and sediments of these fish, the relatively high abundance of microplastics in the GI tracts of fish suggests environmental exposure may be above threshold concentrations for risk.

Plasma microparticles from patients with systemic lupus erythematosus modulate the content of miRNAs in U937 cells.

In systemic lupus erythematosus (SLE), the clearance of apoptotic cells and microparticles (MPs) is reduced. Some MPs contain molecules that can modulate immune responses. This study aimed to evaluate the presence of miR-126 and miR-146a in plasma MPs of patients with SLE (SLE MPs) and analyse the ability of MPs to modulate some events in the promonocytic U937 cell line. Circulating MPs were isolated from plasma samples of healthy controls (HCs), patients with SLE and other autoimmune diseases (OAD). MPs were analysed for size and cell origin by flow cytometry and content of miR-126 and miR-146a by RT-qPCR. MPs were then added to U937 cell cultures to evaluate changes in cell phenotype, cytokine expression, content of miR-126 and miR-146a, and levels of IRF5. Patients with active SLE (aSLE) showed an increase in concentration of plasma MPs that positively correlated with the SLEDAI (SLE Disease Activity Index) score. CD14+ MPs were significantly more abundant in patients with SLE than HCs. SLE MPs contained decreased levels of miR-146a, but the miR-126 content in aSLE MPs was increased. The miR-126 content in SLE MPs correlated positively with the SLEDAI score. The treatment of U937 cells with MPs from HCs and patients induced reduced expression of HLA-DR, CD18 and CD119, increased frequency of IL-6+ and TNF-α+ cells, accumulation of IL-8 in culture supernatants, increased miR-126levels and decreased miR-146a content, but no change in the expression of IRF5. These findings suggest that plasma MPs, especially SLE MPs, could modulate some biological events in U937 cells.

Using embedded alginate microparticles to tune the properties of in situ forming poly(N-isopropylacrylamide)-graft-chondroitin sulfate bioadhesive hydrogels for replacement and repair of the nucleus pulposus of the intervertebral disc.

Low back pain is a major public health issue associated with degeneration of the intervertebral disc (IVD). The early stages of degeneration are characterized by the dehydration of the central, gelatinous portion of the IVD, the nucleus pulposus (NP). One possible treatment approach is to replace the NP in the early stages of IVD degeneration with a hydrogel that restores healthy biomechanics while supporting tissue regeneration. The present study evaluates a novel thermosensitive hydrogel based on poly(N‐isopropylacrylamide‐graft‐chondroitin sulfate) (PNIPAAM‐g‐CS) for NP replacement. The hypothesis was tested that the addition of freeze‐dried, calcium crosslinked alginate microparticles (MPs) to aqueous solutions of PNIPAAm‐g‐CS would enable tuning of the rheological properties of the injectable solution, as well as the bioadhesive and mechanical properties of the thermally precipitated composite gel. Further, we hypothesized that the composite would support encapsulated cell viability and differentiation. Structure‐material property relationships were evaluated by varying MP concentration and diameter. The addition of high concentrations (50 mg/mL) of small MPs (20 ± 6 μm) resulted in the greatest improvement in injectability, compressive mechanical properties, and bioadhesive strength of PNIPAAm‐g‐CS. This combination of PNIPAAM‐g‐CS and alginate MPs supported the survival, proliferation, and differentiation of adipose derived mesenchymal stem cells toward an NP‐like phenotype in the presence of soluble GDF‐6. When implanted ex vivo into the intradiscal cavity of degenerated porcine IVDs, the formulation restored the compressive and neutral zone stiffnesses to intact values and resisted expulsion under lateral bending. Overall, results indicate the potential of the hydrogel composite to serve as a scaffold for supporting NP regeneration. This work uniquely demonstrates that encapsulation of re‐hydrating polysaccharide‐based MPs may be an effective method for improving key functional properties of in situ forming hydrogels for orthopedic tissue engineering applications.

Circulating endothelial microparticles: a promising biomarker of acute kidney injury after cardiac surgery with cardiopulmonary bypass

BackgroundCurrent diagnostic strategies for acute kidney injury (AKI) after cardiac surgery with cardiopulmonary bypass (CPB) are nonspecific and limited. Previously, we demonstrated that circulating microparticles (MPs) in patients with valve heart disease (VHD) and congenital heart diseases (CHD) induce endothelial dysfunction and neutrophil chemotaxis, which may result in kidney injury. We also found that circulating MPs increase after cardiac surgery with CPB and are related to cardiac function. However, the relationship between circulating MPs and AKI after CPB is unknown.MethodsEighty-five patients undergoing cardiac surgery with CPB were enrolled. Patients were divided into AKI and non-AKI groups based on the serum creatinine levels at 12 h and 3 d post-CPB. Circulating MPs were isolated from plasma, and their levels including its subtypes were detected by flow cytometer. Independent risk factors for the CPB-associated AKI (CPB-AKI) were determined by multivariate logistic regression analysis. Receiver operating characteristic (ROC) analysis was used to measure the prognostic potential of CPB-AKI.ResultsThe morbidity of AKI at 12 h and 3 d after cardiac surgery with CPB was 40% and 31.76%, respectively. The concentrations of total MPs and platelet-derived MPs (PMP) remained unchanged at 12 h and then increased at 3 d post-CPB, while that of endothelial-derived MPs (EMP) increased at both time points. In patients with AKI, PMP and EMP were elevated compared with the patients without AKI. However, no significant change was detected on monocyte-derived MPs (MMP) at 12 h and 3 d post-CPB. The logistic regression analysis showed that EMP was the independent risk factor for AKI both at 12 h and 3 d post-CPB. The area under ROC for the concentrations of EMP at 12 h and 3 d post-CPB was 0.86 and 0.91, with the specificity up to 0.88 and 0.91, respectively.ConclusionsCirculating EMP may serve as a potential biomarker of AKI after cardiac surgery with CPB.

Circulating microparticles in patients with chronic hepatitis C and changes during direct-acting antiviral therapy.

Microparticles (MPs) are heterogeneous vesicles derived from membranes of different cells. Between 70 to 90% of MPs detected in blood originate from platelets. The release of MPs is associated with proinflammatory and procoagulant states. Elevated levels of MPs have been found in different diseases. We investigated MPs levels in patients with chronic hepatitis C (CHC) and changes in level during treatment using direct-acting antivirotics (DAA). Thirty-six patients with CHC and forty healthy volunteers were included in the study. Concentrations of MPs were determined indirectly by measuring their procoagulant activity in plasma at baseline, end of therapy (EOT), and 12 weeks after EOT when the sustained virological response was assessed (SVR12). All patients achieved SVR12, which was associated with rapid improvement of markers of liver damage and function as well as liver stiffness (P=0.002). MPs levels were significantly higher in CHC patients than in healthy volunteers (P<0.001). No statistically significant decrease was found observed between baseline and SVR12 (P=0,330). Analysis of subpopulations with minimal fibrosis F0-1 (P=0.647), advanced fibrosis F2-4 (P=0.370), women(P=0.847), men (P=0.164) and genotype 1 (P=0.077) showed no significant changes during the follow-up period. MPs levels are higher in CHC patients and remain elevated shortly after achieving SVR. Higher concentrations of MPs in plasma are probably caused by a chronic uncontrolled exaggerated inflammatory response caused by CHC. Longer observation would probably confirm the significance of MPs levels decrease because normalization of liver function, inflammation, and structure after SVR requires more than 12 weeks.