Levels Of Microparticles Research Articles

Annexin V− and tissue factor+ microparticles as biomarkers for predicting deep vein thrombosis in patients after joint arthroplasty

ObjectiveVenous thromboembolism (VTE) is a common and severe complication of joint arthroplasty. Microparticles (MPs) containing phosphatidylserine (PS) and tissue factor (TF) can trigger coagulation in VTE. This study aims to measure and compare MP levels in joint arthroplasty patients with and without VTE. MethodsThis prospective cohort study enrolled 181 patients who underwent joint arthroplasty. Ultrasound examination was used to diagnose VTE on preoperative day 0 and postoperative day 6. MPs were analysed using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and flow cytometry. The levels of platelet-derived microparticles (PMPs), endothelial cell-derived microparticles (EMPs), granulocyte-derived microparticles (GMPs), red cell-derived microparticles (RMPs), monocyte-derived microparticles (MMPs), Annexin V+ MPs (AV+ MPs), and tissue factor+ MPs (TF+ MPs) derived from five kinds of MPs were measured on day 0 (before surgery), 1, 2, 3, 4, 5, and 6 after surgery. ResultsThe levels of AV-TF+ EMPs and AV-TF+ MMPs were significantly increased in patients with VTE on postoperative day 5 compared to those without VTE (P = 0.031 and P = 0.031, respectively). ConclusionAV-TF+ MPs may indicate the development of VTE and serve as predictive markers in joint arthroplasty patients.

Circulating Microparticles Are Differentially Increased in Lowlanders and Highlanders with High Altitude Induced Pulmonary Hypertension during the Cold Season.

The role of microparticles (MPs) and cold in high altitude pulmonary hypertension (HAPH) remains unexplored. We investigated the impact of long-term cold exposure on the pulmonary circulation in lowlanders and high-altitude natives and the role of MPs. Pulmonary hemodynamics were evaluated using Doppler echocardiography at the end of the colder and warmer seasons. We further examined the miRNA content of MPs isolated from the study participants and studied their effects on human pulmonary artery smooth muscle (hPASMCs) and endothelial cells (hPAECs). Long-term exposure to cold environment was associated with an enhanced pulmonary artery pressure in highlanders. Plasma levels of CD62E-positive and CD68-positive MPs increased in response to cold in lowlanders and HAPH highlanders. The miRNA-210 expression contained in MPs differentially changed in response to cold in lowlanders and highlanders. MPs isolated from lowlanders and highlanders increased proliferation and reduced apoptosis of hPASMCs. Further, MPs isolated from warm-exposed HAPH highlanders and cold-exposed highlanders exerted the most pronounced effects on VEGF expression in hPAECs. We demonstrated that prolonged exposure to cold is associated with elevated pulmonary artery pressures, which are most pronounced in high-altitude residents. Further, the numbers of circulating MPs are differentially increased in lowlanders and HAPH highlanders during the colder season.

From pollution to exacerbation in chronic obstructive pulmonary disease

Abstract Air pollution is increasing every year, especially due to the continuous process of industrialization and modernization. In this observational study, we included 38 COPD patients with frequent exacerbating phenotypes and we wanted to see if the values of microparticles with a size of 1.0, 2.5 and 10 μm, recorded in their homes, are above the values recommended by the World Health Organization (WHO). An air quality monitoring source was installed in each patient’s home for at least 24 hr and microparticles with a size of 1.0, 2.5 and 10 μm, temperature, pressure and humidity were measured. MEAN PM2.5 values were higher than the values recommended by the WHO, 25.33 µg/m3 vs. 15 µg/m3. Our analysis showed that the levels of microparticles in the homes of patients with COPD, and frequently exacerbating phenotype, are above the limits recommended by the WHO.

Platelet- and endothelial-derived microparticles in the context of different antiphospholipid antibody profiles.

Studies on microparticles (MPs) in patients with antiphospholipid antibodies (aPL) are sparse and inconclusive. The relation between MPs and different aPL antibody profiles has never been tested. We evaluated the presence of platelet and endothelial microparticles in patients positive for IgG anti-β2-glycoprotein I (aβ2GPI) antibodies according to triple, double and single positive aPL profiles. Megamix (Biocytex) was used to set up the MPs gating according to the datasheet. Markers of Platelet Microparticles (PMPs) were CD41a-PE and annexin-V-FITC that was used to determine phosphatidylserine (PS) exposure. CD144-FITC was used as a marker of Endothelial Microparticles (EMPs). The number of total MPs and EMPs was significantly higher in triple positive groups with respect to single positive group and showed a significant correlation with IgG aβ2GPI titers. The number PMPs was the lowest in triple positive group and inversely correlated with IgG aβ2GPI titers. Elevated levels of total MPs and EMPs suggest a state of vascular activation in IgG aβ2GPI positive individuals according to the number of positive tests. PMPs may be fast cleared from circulation in high risk triple positive patients.

Upregulation of cytokine signalling in platelets increases risk of thrombophilia in severe COVID-19 patients

Abnormal coagulation dynamics, including disseminated intravascular coagulopathy, pulmonary embolism, venous thromboembolism and risk of thrombosis are often associated with the severity of COVID-19. However, very little is known about the contribution of platelets in above pathogenesis. In order to decipher the pathophysiology of thrombophilia in COVID-19, we recruited severely ill patients from ICU, based on the above symptoms and higher D-dimer levels, and compared these parameters with their asymptomatic counterparts. Elevated levels of platelet-derived microparticles and platelet-leukocyte aggregates suggested the hyperactivation of platelets in ICU patients. Strikingly, platelet transcriptome analysis showed a greater association of IL-6 and TNF signalling pathways in ICU patients along with higher plasma levels of IL-6 and TNFα. In addition, upregulation of pathways like blood coagulation and hemostasis, as well as inflammation coexisted in platelets of these patients. Further, the increment of necrotic pathway and ROS-metabolic processes in platelets was suggestive of its procoagulant phenotype in ICU patients. This study suggests that higher plasma IL-6 and TNFα may trigger platelet activation and coagulation, and in turn aggravate thrombosis and hypercoagulation in severe COVID-19 patients. Therefore, the elevated IL-6 and TNFα, may serve as potential risk factors for platelet activation and thrombophilia in these patients.

Angiogenic content of microparticles in patients with diabetes and coronary artery disease predicts networks of endothelial dysfunction

BackgroundElevated endothelial microparticles (EMPs) levels are surrogate markers of vascular dysfunction. We analyzed EMPs with apoptotic characteristics and assessed the angiogenic contents of microparticles in the blood of patients with type 2 diabetes (T2D) according to the presence of coronary artery disease (CAD).MethodsA total of 80 participants were recruited and equally classified as (1) healthy without T2D, (2) T2D without cardiovascular complications, (3) T2D and chronic coronary artery disease (CAD), and (4) T2D and acute coronary syndrome (ACS). MPs were isolated from the peripheral circulation, and EMPs were characterized using flow cytometry of CD42 and CD31. CD62E was used to determine EMPs’ apoptotic/activation state. MPs content was extracted and profiled using an angiogenesis array.ResultsLevels of CD42- CD31 + EMPs were significantly increased in T2D with ACS (257.5 ± 35.58) when compared to healthy subjects (105.7 ± 12.96, p < 0.01). There was no significant difference when comparing T2D with and without chronic CAD. The ratio of CD42-CD62 +/CD42-CD31 + EMPs was reduced in all T2D patients, with further reduction in ACS when compared to chronic CAD, reflecting a release by apoptotic endothelial cells. The angiogenic content of the full population of MPs was analyzed. It revealed a significant differential expression of 5 factors in patients with ACS and diabetes, including TGF-β1, PD-ECGF, platelet factor 4, serpin E1, and thrombospondin 1. Ingenuity Pathway Analysis revealed that those five differentially expressed molecules, mainly TGF-β1, inhibit key pathways involved in normal endothelial function. Further comparison of the three diabetes groups to healthy controls and diabetes without cardiovascular disease to diabetes with CAD identified networks that inhibit normal endothelial cell function. Interestingly, DDP-IV was the only differentially expressed protein between chronic CAD and ACS in patients with diabetes.ConclusionOur data showed that the release of apoptosis-induced EMPs is increased in diabetes, irrespective of CAD, ACS patients having the highest levels. The protein contents of MPs interact in networks that indicate vascular dysfunction.

Confirmation of endotypes based on levels of eosinophil, mast cell and basophil microparticles in nasal lavage fluids in chronic rhinosinusitis with nasal polyps using two Northwestern Memorial Hospital cohorts

Microparticles (MPs) are extracellular vesicles that are released by shedding from plasma membrane of activated cells and new biomarkers to evaluate status of cell activation. MP profilings of activated eosinophils, mast cells and basophils in nasal mucosa in chronic rhinosinusitis with nasal polyps (CRSwNP) remain unclear.

Circulating Microparticles in the Pathogenesis and Early Anticoagulation of Thrombosis in COVID-19 With Kidney Injury.

As more is learned about the pathophysiological mechanisms of COVID-19, systemic thrombosis has been recognized as being associated with more severe clinical manifestations, mortality and sequelae. As many as 40% of patients admitted to the hospital due to COVID-19 have acute kidney injury, with coagulation abnormalities the main cause of impaired function. However, the mechanism of renal thrombosis and the process leading to kidney injury are unclear. Microparticles (MPs) are membrane bubbles released in response to activation, injury or apoptosis of cells. The phosphatidylserine (PS) exposed on the surface of MPs provides binding sites for endogenous and exogenous FXase complexes and prothrombin complexes, thus providing a platform for the coagulation cascade reaction and facilitating clot formation. In the context of COVID-19 infection, viral attack leads immune cells to release cytokines that damage circulating blood cells and vascular endothelial cells, resulting in increased MPs levels. Therefore, MPs can be used as a risk factor to predict renal microthrombosis and kidney injury. In this paper, we have summarized the latest data on the pathophysiological mechanism and treatment of renal thrombosis caused by MPs in COVID-19, revealing that the coagulation abnormality caused by MP and PS storms is a universal progression that aggravates the mortality and sequelae of COVID-19 and potentially other pandemic diseases. This paper also describes the risk factors affecting renal thrombosis in COVID-19 from the perspective of the Virchow’s triad: blood hypercoagulability, vascular endothelial injury, and decreased blood flow velocity. In summary, given the serious consequences of thrombosis, current guidelines and clinical studies suggest that early prophylactic anticoagulant therapy reduces mortality and improves clinical outcomes. Early anticoagulation, through inhibition of PS-mediated coagulopathy, allows maintenance of unobstructed blood circulation and oxygen delivery thereby facilitating the removal of inflammatory factors, viruses, MPs, and dead or damaged cells, and expediting patient rehabilitation.

Abstract 11165: Stimulated Release of Apoptosis- Induced Endothelial Microparticles in Patients with Diabetes and Coronary Artery Disease

Introduction: High endothelial microparticles (EMPs) levels could be used as a marker of vascular dysfunction. Hypothesis: The release of EMPs with apoptotic characteristics in the blood of patients with diabetes is different according to the presence of CAD, and further distinct between chronic CAD and ACS. Methods: A total of 80 participants were recruited and equally classified as: 1) healthy participants without diabetes, 2) healthy diabetics without micro or macro-vascular complications, 3) participants with T2D and chronic CAD, and 4) participants with T2D and ACS. MPs were isolated using ExoQuick-LP TM and analysed using flow cytometry of CD42 and CD31. CD62E was used to determine the apoptotic/activation state of the EMPs. MP content was extracted and profiled using angiogenesis array (R&amp;D systems). Results: Mean age of participants was 56 ±10. Levels of CD42- CD31+ EMPs were significantly increased in diabetics with acute ACS (257.5±35.58) when compared to healthy subjects (105.7±12.96, p&lt;0.01). There was no significant difference when comparing diabetics, with and without chronic CAD. The ratio of CD42-CD62+/ CD42-CD31+ EMPs was reduced in all diabetic groups, with further reduction in ACS when compared to chronic CAD, reflecting a release by apoptotic endothelial cells. The angiogenic content of the full population of MPs was analysed and revealed a significant differential expression of 5 factors in patients with ACS and diabetes: TGF-β1, PD-ECGF, platelet factor 4, serpin E1 and thrombospondin 1 (Figure 1). Ingenuity Pathway Analysis revealed of those 5 differentially expressed molecules, mainly TGF-β1, causes an inhibition of key pathways involved in normal endothelial function. Conclusions: Our data showed that the release of apoptosis-induced EMPs is increased in diabetes, irrespective of the presence of CAD, ACS patients having the highest levels. The protein contents of MPs interact in networks that are indicative of vascular dysfunction.

Transcatheter aortic valve thrombosis: a review of potential mechanisms.

Transcatheter aortic valve (TAV) thrombosis has been recognized as a significant problem that sometimes occurs as early as within 30 days after valve implantation, leading to increased concerns of stroke and long-term valve durability. In this article, a critical summary of the relevant literature on identifying potential mechanisms of TAV thrombosis from the perspective of the well-known Virchow's triad, which comprises blood flow, foreign materials and blood biochemistry, is presented. Blood flow mechanisms have been the primary focus thus far, with a general consensus on the flow mechanisms with respect to haemodynamic conditions, the influence of TAV placement and expansion and the influence of coronary flow. Less attention has been paid to the influence of blood biochemistry and foreign materials (and related endothelial damage), with little consensus among studies with regards to platelet and/or microparticle levels post-TAV implantation. Finally, we discuss the future outlook for research with unanswered scientific questions.

Formation, structure, properties of chitosan aspartate and metastable state of its solutions for obtaining nanoparticles

Chitosan (200 kDa) dissolution in an aqueous solution of L-aspartic acid, physicochemical properties and features of the resulting chitosan salt were studied by conductometry, potentiometry, viscometry, turbidimetry, IR and NMR spectroscopy, and X-ray diffractometry. Chitosan aspartate is a water-soluble hydrated polymorph exhibiting properties of a cationic polyelectrolyte with an effective macromolecular coil radius 60–75 nm. The specific conductivity, dielectric constant, viscosity and pH of the chitosan – L-aspartic acid – water system change over time after preparation due to counterion-polycation association to form ion pairs, multiplet structures, and their subsequent aggregation. As a result, nanoparticles (40–90 nm) are formed after ~24 h, microparticles (0.6–1.4 μm) are after ~48 h, and precipitation occurs after 72–96 h. The precipitated phase is a water-insoluble chitosan salt with a developed system of H-bonds and high crystallinity degree. Chitosan nanoparticles have high biocompatibility and the ability to accelerate the proliferative activity of epithelial cells. HypothesisIon pairs and multiplets are formed in the chitosan – L-aspartic acid – water system due to counterion association, which leads to phase segregation of the polymer substance at the level of nanoparticles and microparticles.

Subclinical markers of cardiovascular toxicity of benzene inhalation in mice

Benzene is a ubiquitous environmental pollutant. Recent population-based studies suggest that benzene exposure is associated with an increased risk for cardiovascular disease. However, it is unclear whether benzene exposure by itself is sufficient to induce cardiovascular toxicity. We examined the effects of benzene inhalation (50 ppm, 6 h/day, 5 days/week, 6 weeks) or HEPA-filtered air exposure on the biomarkers of cardiovascular toxicity in male C57BL/6J mice. Benzene inhalation significantly increased the biomarkers of endothelial activation and injury including endothelial microparticles, activated endothelial microparticles, endothelial progenitor cell microparticles, lung endothelial microparticles, and activated lung and endothelial microparticles while having no effect on circulating levels of endothelial adhesion molecules, endothelial selectins, and biomarkers of angiogenesis. To understand how benzene may induce endothelial injury, we exposed human aortic endothelial cells to benzene metabolites. Of the metabolites tested, trans,trans-mucondialdehyde (10 μM, 18h) was the most toxic. It induced caspases-3, -7 and -9 (intrinsic pathway) activation and enhanced microparticle formation by 2.4-fold. Levels of platelet-leukocyte aggregates, platelet macroparticles, and a proportion of CD4+ and CD8+ T-cells were also significantly elevated in the blood of the benzene-exposed mice. We also found that benzene exposure increased the transcription of genes associated with endothelial cell and platelet activation in the liver; and induced inflammatory genes and suppressed cytochrome P450s in the lungs and the liver. Together, these data suggest that benzene exposure induces endothelial injury, enhances platelet activation and inflammatory processes; and circulatory levels of endothelial cell and platelet-derived microparticles and platelet-leukocyte aggregates are excellent biomarkers of cardiovascular toxicity of benzene.

Levels of procoagulant microparticles expressing phosphatidylserine contribute to bleeding phenotype in patients with inherited thrombocytopenia.

Inherited thrombocytopenia is a heterogeneous group of hereditary disorders with varying bleeding tendencies, not simply related to platelet count. Platelets transform into different subpopulations upon stimulation, including procoagulant platelets and platelet microparticles (PMPs), which are considered critical for haemostasis. We aimed to investigate whether abnormalities in PMP and procoagulant platelet function were associated with the bleeding phenotype of inherited thrombocytopenia patients. We enrolled 53 inherited thrombocytopenia patients. High-throughput sequencing of 36 inherited thrombocytopenia related genes was performed in all patients and enabled a molecular diagnosis in 57%. Bleeding phenotype was evaluated using the ISTH bleeding assessment tool, dividing patients into bleeding (n = 27) vs. nonbleeding (n = 26). Unstimulated and ADP, TRAP or collagen-stimulated PMP and procoagulant platelet functions were analysed by flow cytometry using antibodies against granulophysin (CD63), P-selectin (CD62P), activated GPIIb/IIIa (PAC-1) and a marker for phosphatidylserine expression (lactadherin). Procoagulant platelets were measured in response to collagen stimulation. An in-house healthy reference level was available. Overall, higher levels of activated platelets, PMPs and procoagulant platelets were found in nonbleeding patients compared with the reference level. Nonbleeding patients had higher proportions of phosphatidylserine and PMPs compared with bleeding patients and the reference level, in response to different stimulations. Interestingly, this finding of high proportions of phosphatidylserine and PMPs was limited to PMPs, and not present in procoagulant platelets or platelets. Our findings indicate that nonbleeding inherited thrombocytopenia patients have compensatory mechanisms for improved platelet subpopulation activation and function, and that generation of phosphatidylserine expressing PMPs could be a factor determining bleeding phenotype in inherited thrombocytopenia.

Mimicking Low pH Virus Inactivation Used in Antibody Manufacturing Processes: Effect of Processing Conditions and Biophysical Properties on Antibody Aggregation and Particle Formation.

Low pH virus inactivation (VI) step is routinely used in antibody production manufacturing. In this work, a mimic of the VI step was developed to focus on evaluating adverse effects on product quality. A commercially available lab-scale glass reactor system was utilized to assess impacts of process and solution conditions on process-induced monoclonal antibody particle formation. Flow imaging was found to be more sensitive than light obscuration in detecting microparticles. NaOH as a base titrant increased protein microparticles more than Tris. Both stirring and NaCl accelerated particle formation, indicating that interfacial stress and protein colloidal stability were important factors. Polysorbate 80 was effective at suppressing particle formation induced by stirring. In contrast, trehalose led to higher microparticle levels suggesting a conformational stabilizer may have other adverse effects during titration with stirring. Additionally, conformational and colloidal stability of antibodies were characterized to investigate the potential roles of antibody physicochemical properties in microparticle formation during VI. The stability data were supportive in rationalizing particle formation behaviors, but they were not predictive of particle formation during the mimicked viral inactivation steps. Overall, the results demonstrate the value of testing various solution and processing conditions in a scaled-down system prior to larger-scale VI bioprocesses.

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.

Off-label use of plastic syringes with silicone oil for intravenous infusion bags of antibodies

The formation of particulates in post-manufacture biopharmaceuticals continues to be a major concern in medical treatment. This study was designed to evaluate the content of micro-sized particles using flow imaging of antibodies in intravenous infusion bags. Intravenous immunoglobulin (IVIG) and Avastin® were selected as model drugs and plastic syringes with and without silicone oil (SO) were used to transfer the drugs into the bags (0.9% saline or 5% dextrose). Antibodies exposed to SO had significantly increased levels of microparticles in both diluents, suggesting SO accelerates particle formation, especially at a higher antibody concentration. Even before the drop stress, their count exceeded the USP guideline. Dropping the bags in the presence of SO produced larger microparticles. Meanwhile, air bubbles were retained longer in saline suggesting more protein film formation on its air–water interface. Overall, both drugs were conformationally stable and produced less particles in dextrose than in saline.

MICROPARTICLES AS A PREDICTIVE BIOMARKER IN ACUTE MYOCARDIAL INFARCTION

Background: Microparticles are small vesicles, between 0.1 and 1 μm in diameter. There are found in low concentrations in the plasma under physiological conditions and increased in pathological conditions. Objective: To find the correlation between circulating microparticles levels and thrombotic burden in acute myocardial infarction. Patients and methods: The study was conducted on 86 patients presented with acute myocardial infarction with ST-elevation, to the emergency Department at Ahmed Maher Teaching Hospital from September 1st 2019 till February 28th 2020. They were compared with 14 healthy individuals with identical demographic characteristics not suffering from any disease. Serum microparticles (CD41a) & (CD62E) and serum CKMB, troponin I, AST, and creatinine levels were measured in both groups. Results: There were significant elevation of all parameters cardiac marker, CD41, and CD62E levels were observed in all patients of STEMI patients compared to the control group (p=<0.001). Conclusion: In STEMI patients, the serum CD41a and CD62E levels rise due to their property as proinflammatory and thrombtic CD41 & CD62E can be used as a predictor of STEMI.

Biomarkers of Platelet Activation and Their Prognostic Value in Patients in Sepsis Associated Coagulopathy

Introduction:Sepsis-associated disseminated intravascular coagulation (SAC) is associated with marked hemostatic changes including transient thrombocytopenia due to their enodogenous activation / consumption. Platelets are decreased in SAC and exhibit compromised function. Patients with SAC are at an increased risk of thrombosis and / or bleeding. The widespread activation of platelets contribute to vascular occlusions, fibrin deposition, multi-organ dysfunction, contributing to a two-fold increase in mortality. At this time there is no single biomarker or laboratory test that can effectively diagnose SAC; however, the International Society on Thrombosis and Hemostasis (ISTH) has introduced a scoring system based on laboratory parameters such as platelet count, clotting time, and levels of markers of thrombosis to calculate SAC severity in terms of DIC score. Measurement of activation markers that describe the interplay between inflammation and platelet function may provide insight into the pathogenesis of SAC. The purpose of this study was to measure markers of platelet function in the plasma of patients with clinically established SAC and to determine their association to disease severity and outcome.Materials and Methods:Plasma samples from 103 adult intensive care unit (ICU) patients with sepsis and suspected disseminated intravascular coagulation (DIC) were acquired from the University of Utah Hospital at the time of ICU admission as well as on days 4 and 8. Samples with relevant clinical information were transported to Loyola University Chicago under an IRB-approved protocol and stored at -80˚C prior to analysis. Plasma samples from healthy individuals (n=50) were purchased from George King Biomedical (Overland, KS). DIC scores were calculated using the ISTH scoring algorithm which incorporates platelet count, D-Dimer, INR, and fibrinogen. Patients were categorized as having no DIC, non-overt DIC, or overt DIC. Plasma levels of CD40L, von Willebrand Factor (vWF), platelet factor-4 (PF-4), and microparticles (MP) were quantified using commercially available ELISAs performed according to manufacturer instructions.Results:Markers of platelet activation were significantly elevated in patients with sepsis alone and with suspected DIC compared to normal healthy individuals on ICU day 0 (p<0.001). Levels of platelet-associated biomarkers were compared between survivors and non-survivors. PF-4 was significantly decreased in non-survivors compared to survivors (p = 0.0156). No other significant variations based on survival or based on DIC score category were observed.Since platelet count is often dramatically reduced in patients with DIC, the relationship between platelet count and levels of markers of platelet activity was also evaluated. Patients were stratified based on platelet count and levels of markers were compared between groups. CD40L, vWF, PF4, and MP showed significant variation based on platelet count, with all markers exhibiting stepwise elevation with increasing platelet count (Table 1).Conclusion: Markers of platelet activation were significantly elevated in patients with SAC compared to healthy individuals. This increase was independent of platelet count, underscoring the importance of activation processes to this disease process. Of the markers studied, PF4 showed significant difference based on DIC score or mortality, and differentiated the non-survivors compared to survivors. Levels of CD40L, vWF, PF4, and MP showed significant association with platelet count, increasing in a stepwise manner with increases in platelet count. These studies also suggest that the markers of platelet activation in SAC are primarily regulated by the number of circulating platelets and may be independent of the factors leading to their endogenous consumption. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Abstract P031: Endothelial Microparticles In Pediatric Obesity

Introduction: Endothelial activation represents one of the earliest signs of the atherosclerotic process. Microparticles (MPs) in plasma, particularly endothelial MPs (EMPs) are reproducible biomarkers of endothelial dysfunction with a simple blood draw. The goal of this study was to examine the association of obesity with MPs, EMPs (CD31+/CD41– and/or CD 144+/CD31–), and activated EMPs (CD106+). Hypothesis: We hypothesized that higher body mass index (BMI), body fat percent (BF%), and visceral adipose tissue (VAT) would be associated with higher levels of MPs, EMPs, and activated EMPs. Methods: This was a cross-sectional study of 280 children and adolescents ages 8-18 years old. Whole venous blood was collected and processed for platelet free-plasma (PFP) collection less than 3 hours after being drawn. PFP samples were prepared using serial centrifugations and then frozen as 100 μl aliquots at -80 ° C. MPs were measured using flow cytometry with size ranging from 0.3 to 1.0 μm. EMPs were defined as MP with CD31+/CD41– and/or CD 144+/CD31–. Active EMP was identified as EMP with CD 106+. BF% and VAT were measured using dual X-ray absorptiometry. Linear (total MPs and EMPs) and logistic (activated EMPs) regression models were used to examine the associations with adiposity group, BF%, and VAT, adjusting for Tanner stage, sex, and race. Results: The mean age of the cohort was 12.7 years, consisting of 147 females and BMI distribution: 112 normal-weight, 77 overweight/obesity, 91 severe obesity. Youth with overweight/obesity and severe obesity had higher numbers of total MPs (28,690 per μL PFP/g [-2,315, 59,695], p=0.07 and 52,744 per μL PFP/g [22,163, 83,324], p&lt;0.001, respectively) and total EMPs (350 per μL PFP/g [81, 618], p=0.011 and 278 per μL PFP/g [13, 543], p=0.040, respectively) compared to peers with normal weight. In the entire cohort, higher BF% was associated with higher MPs (1,646 per μL PFP per percent [509, 2,783], p=0.005) and EMPs (11 per μL PFP per percent [2, 21], p=0.023), and higher VAT was associated with higher MPs (34 per μL PFP/g [11, 57], p=0.004) but not EMPs. Logistic regression analysis showed higher odds of active EMPs (odds ratio, 1.72 [1.0, 2.97], p=0.0502) in those with a BMI &gt;85 th percentile compared to youth with a BMI &lt;85 th percentile. In the entire cohort, BF% (odds ratio, 1.02 [1.00, 1.04], p=0.108) and VAT (odds ratio, 1.00 [1.00, 1.00], p=0.472) were not significantly associated with active EMPs. Conclusions: Higher levels of endothelial cell damage and activation were associated with obesity and excess adiposity in youth. The potential role of MPs and EMPs as useful biomarkers of cardiovascular disease risk merits further study.

Vascular inflammation in moderate‐to‐severe atopic dermatitis is associated with enhanced Th2 response

In atopic dermatitis (AD), some studies have shown an association with increased cardiovascular disease in certain populations. However, other investigations found modest or no association. Despite conflicting results, molecular profiling studies in both AD skin and blood have demonstrated upregulation of atherosclerosis and cardiovascular risk-related markers. However, the underlying mechanisms connecting AD to vascular inflammation/atherosclerosis are unknown. In this study, we aim to determine factors associated with vascular inflammation/atherosclerosis in AD patients. We used 18-FDG PET-CT to characterize vascular inflammation in AD patients and healthy subjects. In parallel, we assessed their skin and blood immune profiles to determine AD-related immune biomarkers associated with vascular inflammation. We also assessed levels of circulating microparticles, which are known to be associated with increased cardiovascular risk. We found significant correlations between vascular inflammation and Th2-related products in skin and blood of AD patients as well as atherosclerosis-related markers that were modulated by dupilumab. Circulating levels of endothelial microparticles were significantly higher in severe AD patients and tended to correlate with vascular inflammation assessed by PET-CT. Vascular inflammation in AD is associated with enhanced Th2 response and clinical severity, which may explain cardiovascular comorbidities observed in select AD populations. Larger prospective studies are needed to further evaluate vascular inflammation and cardiovascular events and mortality in AD patients. Finally, as dupilumab treatment demonstrated significant modulation of atherosclerosis-related genes in AD patients compared to placebo, these data suggest that modulation of vascular inflammation with systemic treatment should be explored in patients with AD.