Effects of Tofogliflozin and Anagliptin Alone or in Combination on Glucose Metabolism and Atherosclerosis-Related Markers in Patients with Type 2 Diabetes Mellitus

Purpose

In people with type 2 diabetes mellitus (T2DM), both glucose metabolism abnormalities and atherosclerosis risk are significant concerns. This study aims to investigate the effects of the sodium-glucose cotransporter 2 inhibitor tofogliflozin (TOFO) and the dipeptidyl peptidase-4 inhibitor anagliptin (ANA) on markers of glucose metabolism and atherosclerosis when administered individually or in combination.

Methods

Fifty T2DM patients were divided into two groups (receiving either TOFO or ANA monotherapy) and observed for 12 weeks (observation points: 0 and 12 weeks). The TOFO and ANA groups were then further treated with ANA and TOFO, respectively, and the patients were observed for an additional 36 weeks (observation points: 24 and 48 weeks). Therapeutic effects and various biomarkers were compared between the two groups at the observation points.

Results

Combination therapy led to significant improvements in HbA1c levels and atherosclerosis markers. Additionally, the TOFO pretreatment group exhibited significant reductions in sLOX-1 and IL-6 levels.

Conclusion

The increase in sLOX-1 and IL-6 levels, which indicates the response of scavenger receptors to oxidized low-density lipoproteins in people with T2DM, is mitigated following TOFO and ANA combination therapy. TOFO alone or in combination with ANA may be beneficial for preventing atherosclerosis development in people with T2DM, in addition to its effect on improving HbA1c levels.

MicroRNA miR-18a-3p promotes osteoporosis and possibly contributes to spinal fracture by inhibiting the glutamate AMPA receptor subunit 1 gene (GRIA1)

The promoting role that miR-18a-3p plays in osteoporosis (OP) has been previously described. However, the detailed mechanisms remain unclear. Bone tissues were collected from healthy patients, OP patients, and patients with osteoporotic spinal fractures. An osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) was constructed to detect the expression of miR-18a-3p and glutamate AMPA receptor subunit 1 (GRIA1). Alkaline phosphatase (ALP) activity and a qRT-PCR analysis were used to detect ALP content, alizarin red S staining was used to detect calcium deposition, and qRT-PCR was used to evaluate runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), and osteopontin (OPN) expression levels. A dual-luciferase reporter and RNA pull-down assay was used to verify the targeted correlation between miR-18a-3p and GRIA1. We observed an increase in miR-18a-3p expression and a decrease in GRIA1 expression in OP and osteoporotic vertebral fracture patients. Upregulation of miR-18a-3p restrained the activity and expression of ALP in hBMSCs, inhibited the expression of RUNX2, OCN, and OPN, and inhibited calcium deposition. Knockdown of miR-18a-3p or upregulation of GRIA1 promoted osteogenic differentiation. Our findings indicate that miR-18a-3p promotes OP progression by regulating GRIA1 expression, suggesting that targeting miR-18a-3p/GRIA1 may be a therapeutic strategy for OP.

Advanced chronic kidney disease is associated with higher serum concentration of monocyte microparticles

Advanced chronic kidney disease is associated with high rates of cardiovascular disease. Considering the crucial role of capillaries in renal function, our study aimed to evaluate microparticles related to vascular physiology examining the link between stages of chronic kidney disease with circulating endothelial (EMP), platelet (PMP) and monocytic (MMP) microparticles. Cross-sectional study with blinded endpoints included subjects of both sexes, aged 40-75 years (n = 247), with established cardiovascular disease (coronary heart disease, ischemic stroke, or peripheral artery disease). They were stratified 1:1 by the presence or absence of decreased glomerular filtration rate (GFR < 60 mL/min/1.73 m²) estimated by the CKD-EPI criteria, and according to the stages of CKD. Microparticles were quantified by flow-cytometry using specific antibodies to identify endothelial, platelet, and monocytic derived microparticles. Higher percentages of circulating MMP (p = 0.036), but not for EMP or PMP, were observed in subjects with reduced GFR. Circulating MMP were also related to the stages of chronic kidney disease (trend analysis across renal stages, p = 0.038). Higher percentages of circulating MMP were found in subjects with reduced GFR, and their percentages were progressively higher according to the stage of chronic renal function.

Effects of Cell-Derived Microparticles on Immune Cells and Potential Implications in Clinical Medicine

In the past few years, interest has increased in cell-derived microparticles (MPs), which are defined by their size of from 0.1 to 1 μm, and can be derived from various cell types, including endothelial cells, leukocytes, red blood cells (RBCs), and platelets. These MPs carry negatively charged phosphatidylserine (PS) on their surfaces and proteins packaged from numerous cellular components. MPs that have been shed by the body can play important roles in the pathophysiology of diseases and can affect various biological systems. Among these systems, the immune components have been shown to be modulated by MPs. Therefore, understanding the roles of MPs in the immune system is crucial to developing alternative therapeutic treatments for diseases. This review describes the effects of MPs on various immune cells and provides plausible potential applications of the immune-modulating properties of MPs in clinical medicine.

Recent Advances in the Use of Exosomes in Sjögren's Syndrome

Sjögren's syndrome (SS) is a chronic autoimmune disorder of the exocrine glands mediated by lymphocytic infiltrates damaging the body tissues and affecting the life quality of patients. Although traditional methods of diagnosis and treatment for SS are effective, in the time of personalized medicine, new biomarkers, and novel approaches are required for the detection and treatment of SS. Exosomes represent an emerging field in the discovery of biomarkers and the management of SS. Exosomes, a subtype of extracellular vesicles, are secreted by various cell types and can be found in most bodily fluids. Exosomes are packed with cytokines and other proteins, bioactive lipids, and nucleic acids (mRNA, circular RNA, non-coding RNA, tRNA, microRNA, genomic DNA, and ssDNA), and transport such cargo between cells. Evidence has indicated that exosomes may play roles in processes such as the modulation of the immune response and activation of inflammation. Moreover, due to features such as stability, low immunogenicity and toxicity, long half-life, and the capacity to penetrate the blood-brain barrier, exosomes have also emerged as therapeutic tools for SS. In this review, we summarize existing literature regarding the biogenesis, isolation, and function of exosomes, specifically focusing on exosomes as novel biomarkers and their potential therapeutic uses in SS.

Effect of Physical Exercise on the Release of Microparticles with Angiogenic Potential

Cellular communication has a fundamental role in both human physiological and pathological states and various mechanisms are involved in the crosstalk between organs. Among these, microparticles (MPs) have an important involvement. MPs are a subtype of extracellular vesicles produced by a variety of cells following activation or apoptosis. They are normally present in physiological conditions, but their concentration varies in pathological states such as cardiovascular disease, diabetes mellitus, or cancer. Acute and chronic physical exercise are able to modify MPs amounts as well. Among various actions, exercise-responsive MPs affect angiogenesis, the process through which new blood vessels grow from pre-existing vessels. Usually, the neo vascular growth has functional role; but an aberrant neovascularization accompanies several oncogenic, ischemic, or inflammatory diseases. In addition, angiogenesis is one of the key adaptations to physical exercise and training. In the present review, we report evidence regarding the effect of various typologies of exercise on circulating MPs that are able to affect angiogenesis.

Increased levels of platelet-derived microparticles in pulmonary hypertension

INTRODUCTION

Thrombosis and coagulation abnormalities are thought to be involved in disease progression of pulmonary hypertension. Platelet-derived microparticles (PDMP) are released from platelets following stimulation and have recently been demonstrated to play an important role in pathogenesis of various diseases. This study aimed to evaluate PDMP levels in patients with pulmonary hypertension.

MATERIALS AND METHODS

Our cross-sectional study enrolled a total of 113 participants including 73 patients with pulmonary hypertension and 40 participants to serve as a control group. PDMP levels were measured using a PDMP ELISA kit, which detects glycoproteins CD42a and CD42b. Clinical parameters, including exercise capacity and hemodynamic parameters, were collected, and the relationship to PDMP levels were evaluated.

RESULTS

PDMP levels were significantly higher in patients than in participants in the control group (23.2 ± 39.4 U/mL and 7.8 ± 3.6 U/mL, respectively, P < 0.05). PDMP levels in patients with chronic thromboembolic pulmonary hypertension were correlated with right atrial pressure and cardiac index. PDMP levels were higher in male patients with idiopathic pulmonary arterial hypertension. Furthermore, patients administered a higher dose of epoprostenol had a tendency for lower PDMP levels.

CONCLUSIONS

The data suggest that PDMP levels are increased in patients with pulmonary hypertension. Further study is needed to understand the mechanism and impact of PDMP on disease progression.

Quantitation of Cell-Derived Microparticles in Blood Products and Its Potential Applications in Transfusion Laboratories

Cell-derived microparticles (MPs) are small fragments released from various cells when they are activated or undergo apoptosis. In the field of transfusion medicine, a number of studies have documented increased levels of MPs in blood products, which have been associated with multiple factors, including donor variability, blood component processing, and storage. In addition, transfusions that contain high levels of MPs are linked to posttransfusion complications. Considering the clinical importance of MP levels, transfusion laboratories should routinely screen blood products for them. However, this practice is not yet applied routinely, perhaps in part because of a lack of understanding of how to apply MP data to transfusion medicine. We describe the methods used to quantitate MPs in blood components and discuss the application of these quantitative data in routine transfusion laboratories in order to manage quality, improve the outcomes of transfusions, and minimize their complications.

Platelet-Derived Microparticles are an Important Biomarker in Patients with Cancer-Associated Thrombosis

Background

Platelet-derived microparticles (PDMPs) that ultimately cause vascular complications might be used as a tool to assess thrombotic areas. We identified PDMPs, high-mobility group box-1 (HMGB1) and soluble endothelial protein C receptor (sEPCR) as useful prognosis indicators for cancer-related thrombosis (CAT) to evaluate the utility of PDMPs in cancer patients.

Methods

We investigated 232 cancer patients: 24 (10.3%) had thrombotic complications within 6 months after their first examination. Levels of PDMP and biomarkers were measured by enzyme-linked immunosorbent assay.

Results

The levels of PDMPs, HMGB1 and sEPCR were higher in cancer patients compared with controls. In particular, these levels were significantly elevated in lung cancer patients compared with controls, and all were higher in CAT-positive patients compared with CAT-negative patients. In particular, PDMP levels in CAT-positive patients were significantly elevated compared with CAT-negative patients. PDMP levels were significantly lower in patients who lived for more than 901 days after their first examination compared with previous data. PDMP levels were positively correlated with HMGB1, and caused the dose-dependent elevation of PDMPs in vitro using platelet-rich plasma from healthy persons.

Conclusion

The combined increase in PDMP and HMGB1 levels might be related to CAT in cancer patients. Therefore, coagulatory dysfunction may result from increased levels of these biomarkers and contribute to the poor prognosis of cancer patients.

Potential therapeutic applications of exosomes in different autoimmune diseases

Autoimmune diseases are caused by self-immune responses to autoantigens, which damage body tissues and severely affect the patient's quality of life. Therapeutic drugs are associated with adverse side effects and their beneficial effects are limited to specific populations. Evidence indicates that exosomes which are small vesicles secreted by most cell types and body fluids, and may play roles in both immune stimulation and tolerance since they are involved in many processes such as immune signaling, inflammation and angiogenesis. Exosomes have also emerged as promising tools for therapeutic delivery, given their intrinsic features such as stability, biocompatibility and a capacity for stealth. In this review, we summarize existing literature regarding the production, efficacy, action mechanism, and potential therapeutic uses of exosomes in the contexts of autoimmune diseases such as type 1 diabetes mellitus, multiple sclerosis, systemic lupus erythematosus, rheumatoid arthritis, and Sjogren's syndrome.

Effects of sarpogrelate, eicosapentaenoic acid and pitavastatin on arterioslcerosis obliterans-related biomarkers in patients with type 2 diabetes (SAREPITASO study)

BACKGROUND

The aim was to evaluate the significance of arteriosclerosis obliterans-related biomarkers in patients with type 2 diabetes mellitus (T2DM), and to compare the effects of sarpogrelate, eicosapentaenoic acid (EPA) and pitavastatin on these markers.

PATIENTS AND METHODS

Seventy-two arteriosclerosis obliterans patients with T2DM were classified into two groups, pitavastatin with either sarpogrelate (PS) or EPA (PE). We observed no differences in all biomarkers between the PS and PE groups before treatments.

RESULTS

The levels of body mass index, hemoglobin A1c, soluble E-selectin, soluble vascular cell adhesion molecule 1, plasminogen activator inhibitor-1 and platelet-derived microparticle in the PE group decreased significantly after treatment. The ankle branchial pressure index and adiponectin levels significantly increased in the PE group after treatment compared with the PS group.

CONCLUSION

These results suggest that combination therapy using pitavastatin and EPA possesses an antiatherosclerotic effect and may be beneficial for prevention of vascular complications in patients with T2DM.

Platelet-derived microparticles analysis: Techniques, challenges and recommendations

Platelet-derived microparticles (PMP) are nano size fragments (100-1000 nm) released from platelets under various physiological and pathological conditions. PMP are the most abundant microparticles present in human blood. In recent past years PMP have caught attention of many clinicians as well as researchers for being associated with many diseases like cardio-vascular diseases, infections etc; and have emerged as potential biomarkers. Owing to their small size and diverse phenotype, structure and functions, microparticles including PMP render many challenges during sample handling, estimation and characterization. PMP can be analyzed for many parameters like absolute count, size distribution, functions, content, surface proteins and other phenotypic characteristics. Many techniques have been invented to analyze PMP and other extracellular vesicles for these parameters, but none of them is capable of examining all parameters alone. Apart from it, every technique has its own advantages, limitations and sets of recommendations while using it. This often leads to applying multiple techniques in combination for accurately measuring various parameters and user has to decide cautiously which technique has to be used for their selected parameter testing. This review compiles various methods, techniques, challenges during PMP analysis and recommendations based on previous studies, aimed at guiding users for selecting the most suitable techniques for their experiments with PMP.

Pathogenic roles of microvesicles in diabetic retinopathy

Diabetic retinopathy (DR) is a common complication of diabetes and has been recognized as the leading cause of blindness in adults. Several interrelated molecular pathways are involved in the development of DR. Microvesicles (MVs) are cell membrane vesicles, which carry many biologic molecules, such as mRNAs, microRNAs, transcription factors, membrane lipids, membrane receptors, and other proteins. They may be involved in intercellular communication that can promote inflammation, angiogenesis, and coagulation. Recent studies have indicated that changes in the number and composition of MVs may reflect the pathologic conditions of DR. At present, MVs are well recognized as being involved in the pathophysiological conditions of tumors and cardio-metabolic diseases. However, the roles of MVs in DR have yet to be investigated. In this review, we provide an overview of DR-induced microvascular injury that is caused by MVs derived from endothelial and circulating cells, and discuss the possible mechanisms by which MVs can lead to endothelial dysfunction, coagulation and inflammation. In addition, the protective effects of preconditioned MVs and stem cell-derived MVs are also described . Understanding the involvement of MVs in the pathophysiological conditions of DR may provide insight into the disease mechanisms and may suggest novel therapeutic strategies for DR in the future.

Peripheral blood microvesicles secretion is influenced by storage time, temperature, and anticoagulants

Microvesicles (MVs) are small membrane bound vesicles released from various cell types after activation or apoptosis. In the last decades, MVs received an increased interest as biomarkers in inflammation, coagulation and cancer. However, standardized pre-analytical steps are crucial for the minimization of artifacts in the MV analysis. Thus, this study evaluated the MV release in whole blood samples under the influence of different anticoagulants, storage time and various temperature conditions. Samples were collected from healthy probands and processed immediately, after 4, 8, 24 and 48 hours at room temperature (RT) or 4°C. To identify MV subpopulations, platelet free plasma (PFP) was stained with Annexin V, calcein AM, CD15, CD41 and CD235a. Analysis was performend on a CytoFLEX flow cytometer. Procoagulatory function of MVs was measured using a phospholipid dependent activity and a tissue factor MVactivity assay. Without prior storage, sodium citrate showed the lowest MV count compared to heparin and EDTA. Interestingly, EDTA showed a significant release of myeloid-derived MVs (MMVs) compared to sodium citrate. Sodium citrate showed a stable MV count at RT in the first 8 hours after blood collection. Total MV counts increased after 24 hours in sodium citrated or heparinzed blood which was related to all subpopulations. Interestingly, EDTA showed stable platelet-derived MV (PMV) and erythrocyte-derived MV (EryMV) count at RT over a 48 h period. In addition, the procoagulatory potential increased significantly after 8-hour storage. Based on both, this work and literature data, the used anticoagulant, storage time and storage temperature differently influence the analysis of MVs within 8 hours. To date, sodium citrated tubes are recommended for MV enumeration and functional analysis. EDTA tubes might be an option for the clinical routine due to stable PMV and EryMV counts. These new approaches need to be validated in a clinical laboratory setting before being applied to patient studies. © 2016 International Society for Advancement of Cytometry.

Platelet extracellular vesicles as biomarkers for arterial thrombosis

Arterial thrombosis is a major and global cause of human death and disability. Considering the socioeconomic costs of arterial thrombosis, identification of biomarkers to predict and detect arterial thrombosis at an early stage is an important public health goal. Platelet extracellular vesicles (PEV) are a new candidate biomarker of arterial thrombosis. PEV can be measured in biorepositories, thereby offering the possibility to validate PEV in multicenter clinical trials. PEV analysis has been hitherto hampered by lack of standardized methodology, but substantial technological improvements of PEV detection techniques have been achieved recently. However, before PEV emerge from research tools to clinical applications, a number of issues should be clarified. To facilitate validation of PEV as biomarkers of thrombosis, we discuss (i) whether PEV are useful as biomarkers of thrombosis, (ii) why previous conclusions on PEV concentrations, composition and functions require re-evaluation, and (iii) which questions have to be answered before PEV become clinically useful.

Could Microparticles Be the Universal Quality Indicator for Platelet Viability and Function?

High quality means good fitness for the intended use. Research activity regarding quality measures for platelet transfusions has focused on platelet storage and platelet storage lesion. Thus, platelet quality is judged from the manufacturer's point of view and regulated to ensure consistency and stability of the manufacturing process. Assuming that fresh product is always superior to aged product, maintaining in vitro characteristics should preserve high quality. However, despite the highest in vitro quality standards, platelets often fail in vivo. This suggests we may need different quality measures to predict platelet performance after transfusion. Adding to this complexity, platelets are used clinically for very different purposes: platelets need to circulate when given as prophylaxis to cancer patients and to stop bleeding when given to surgery or trauma patients. In addition, the emerging application of platelet-rich plasma injections exploits the immunological functions of platelets. Requirements for quality of platelets intended to prevent bleeding, stop bleeding, or promote wound healing are potentially very different. Can a single measurable characteristic describe platelet quality for all uses? Here we present microparticle measurement in platelet samples, and its potential to become the universal quality characteristic for platelet production, storage, viability, function, and compatibility.

Effects of febuxostat on platelet-derived microparticles and adiponectin in patients with hyperuricemia

Platelet-derived microparticles (PDMPs) and adiponectin play an important role in the development of atherothrombosis. We investigated the effect of febuxostat on circulating PDMP levels and adiponectin in hyperuricemic patients. Levels of PDMP and biomarkers were measured using an ELISA at baseline and after 2 and 6 months of treatment. Plasma levels of PDMPs and biomarkers were higher, while those of adiponectin were lower in hyperuricemic patients than in normouricemic controls. Uric acid and interleukin (IL)-6 levels decreased significantly in hyperuricemic patients after 2 months of febuxostat treatment. However, PDMP and biomarkers decreased significantly in hyperuricemic patients after only 6 months of febuxostat treatment and adiponectin increased significantly. These results suggest that the effects of febuxostat for PDMPs seen may be the effect on xanthine oxidase but not the decrease of uric acid, and febuxostat may be beneficial for primary prevention of atherothrombosis in hyperuricemic patients.

Role of extracellular vesicles in autoimmune diseases

Extracellular vesicles (EVs) consist of exosomes released upon fusion of multivesicular bodies with the cell plasma membrane and microparticles shed directly from the cell membrane of many cell types. EVs can mediate cell-cell communication and are involved in many processes including inflammation, immune signaling, angiogenesis, stress response, senescence, proliferation, and cell differentiation. Accumulating evidence reveals that EVs act in the establishment, maintenance and modulation of autoimmune processes among several others involved in cancer and cardiovascular complications. EVs could also present biomedical applications, as disease biomarkers and therapeutic targets or agents for drug delivery.

Microparticle and Atherothrombotic Diseases

Microparticles (MPs) are small membrane vesicles that are released from many different cell types by exocytotic budding of the plasma membrane in response to cellular activation or apoptosis. MPs may be involved in both physiological processes and clinical treatments because they express phospholipids, which function as procoagulants. Elevated levels of platelet-derived MPs, endothelial cell-derived MPs, and monocyte-derived MPs are observed in almost all thrombotic diseases occurring in venous and arterial beds. Several studies have shown that the quantity, cellular origin, and composition of circulating MPs depend on the type of disease, the disease state, and medical treatment. Although MPs were initially thought to be small particles with only procoagulant activity, they are now known to have many different functions. An increasing number of studies have identified new implications of elevated MPs in clinical disorders. On the basis of evidence available till date, the present review suggests that MPs may be a useful biomarker in identifying atherothrombosis.

Association of the Plasma Platelet-Derived Microparticles to Platelet Count Ratio with Hospital Mortality and Disseminated Intravascular Coagulopathy in Critically Ill Patients

AIM

The role of platelet-derived microparticles (PDMPs) in the crosstalk between coagulopathy and inflammation in critically ill patients remains unclear. The aim of this cohort observational study was to investigate the associations between the PDMP levels and hospital mortality or disseminated intravascular coagulopathy (DIC).

METHODS

This study included 119 patients who were admitted to the ICU. The PDMP levels were measured using an enzyme-linked immunosorbent assay three times a week, for a total of 372 samples. We calculated the maximum (max) PDMP value, max PDMP/platelet (PDMP/Plts) ratio (converted to the PDMP levels per 10(4) platelets) and nadir platelet count during the ICU stay. Baseline patient data and scores, including the Japanese Association for Acute Medicine (JAAM) DIC score, were collected, and potential predictors were analyzed for possible associations with hospital mortality.

RESULTS

The max PDMP/Plts ratio was significantly different comparing the survivors (n=98: median, 2.54) and non-survivors (n=21: median 17.59; p＜0.001). There was a weak but statistically significant negative correlation between the max PDMP level and nadir platelet count (r=-0.332, p＜0.001). The max PDMP level and max PDMP/Plts ratio were higher in the DIC group (81.48 and 9.27, respectively) than in the non-DIC group (34.88 and 2.35, p=0.001 and p＜0.001, respectively). The max PDMP/Plts ratio was the only variable found to be independently associated with hospital mortality according to a multivariate logistic regression analysis.

CONCLUSIONS

PDMPs are involved in the development of DIC but are not related to hospital mortality. There is a good association between the PDMP/Plts ratio and hospital mortality and/or DIC in critically ill patients.

Clinical significance of procoagulant microparticles

Microparticles (MPs) are small membrane vesicles that are released from many different cell types by exocytic budding of the plasma membrane in response to cellular activation or apoptosis. MPs may also be involved in clinical diseases because they express phospholipids, which function as procoagulants. Although flow cytometry is the most widely used method for studying MPs, some novel assays, such as tissue factor-dependent procoagulant assay or the ELISA method, have been reported. However, the use of quantification of MP as a clinical tool is still controversial. Elevated platelet-derived MP, endothelial cell-derived MP, and monocyte-derived MP concentrations are documented in almost all thrombotic diseases occurring in venous and arterial beds. However, the significance of MPs in various clinical conditions remains controversial. An example of this controversy is that it is unknown if MPs found in peripheral blood vessels cause thrombosis or whether they are the result of thrombosis. Numerous studies have shown that not only the quantity, but also the cellular origin and composition of circulating MPs, are dependent on the type of disease, the disease state, and medical treatment. Additionally, many different functions have been attributed to MPs. Therefore, the number and type of clinical disorders associated with elevated MPs are currently increasing. However, MPs were initially thought to be small particles with procoagulant activity. Taken together, our review suggests that MPs may be a useful biomarker to identify thrombosis.

Microparticles: new light shed on the understanding of venous thromboembolism

Microparticles are small membrane fragments shed primarily from blood and endothelial cells during either activation or apoptosis. There is mounting evidence suggesting that microparticles perform a large array of biological functions and contribute to various diseases. Of these disease processes, a significant link has been established between microparticles and venous thromboembolism. Advances in research on the role of microparticles in thrombosis have yielded crucial insights into possible mechanisms, diagnoses and therapeutic targets of venous thromboembolism. In this review, we discuss the definition and properties of microparticles and venous thromboembolism, provide a synopsis of the evidence detailing the contributions of microparticles to venous thromboembolism, and propose potential mechanisms, by which venous thromboembolism occurs. Moreover, we illustrate a possible role of microparticles in cancer-related venous thromboembolism.

Platelet microparticles: detection and assessment of their paradoxical functional roles in disease and regenerative medicine

There is increasing research on and clinical interest in the physiological role played by platelet microparticles (PMPs). PMPs are 0.1-1-μm fragments shed from plasma membranes of platelets that are undergoing activation, stress, or apoptosis. They have a phospholipid-based structure and express functional receptors from platelet membranes. As they are the most abundant microparticles in the blood and they express the procoagulant phosphatidylserine, PMPs likely complement, if not amplify, the functions of platelets in hemostasis, thrombosis, cancer, and inflammation, but also act as promoters of tissue regeneration. Their size and structure make them instrumental in platelet-cell communications as a delivery tool of platelet-borne bioactive molecules including growth factors, other signaling molecules and micro (mi)RNA. PMPs can therefore be a pathophysiological threat or benefit to the cellular environment when interacting with the blood vasculature. There is also increasing evidence that PMP generation is triggered during blood collection, separation into components, and storage, a phenomenon potentially leading to thrombotic and inflammatory side effects in transfused patients. Evaluating PMPs requires strict pre-analytical and analytical procedures to avoid artifactual generation and ensure accurate assessment of the number, size repartitioning, and functional properties. This review describes the physical and functional methods developed for analyzing and quantifying PMPs. It then presents the functional roles of PMPs as markers or triggers of diseases like thrombosis, atherosclerosis, and cancer, and discusses the possible detrimental immunological impact of their generation in blood components. Finally we review the potential function of PMPs in tissue regeneration and the prospects for their use in therapeutic strategies for human health.

Microvesicles and diabetic complications--novel mediators, potential biomarkers and therapeutic targets

Microvesicles (MVs), also known as microparticles, are small membrane vesicles released from different cell types under different conditions. MVs have been detected in the circulation and in organs/tissues in various diseases, including diabetes. Patients with different types of diabetes and complications have different cellular MV patterns. Studies have shown that MVs may mediate vascular thrombosis, vascular inflammation, angiogenesis, and other pathological processes of the disease through their procoagulant, pro-inflammatory, pro-angiogenic, proteolytic, and other properties. Therefore, MVs contribute to the development of diabetic macrovascular and microvascular complications. In addition, clinical studies have indicated that changes in MV number and composition may reflect the pathophysiological conditions of disease, and therefore, may serve as potential biomarkers for diagnostic and prognostic use. Understanding MVs' involvement in the pathophysiological conditions may provide insight into disease mechanisms and would also be helpful for the development of novel therapeutic strategies in the future. Here, we review the latest publications from our group and other groups and focus on the involvement of MVs in diabetic complications.

Platelet activation dynamics evaluated using platelet-derived microparticles in Kawasaki disease

BACKGROUND

Little is known about the platelet dynamics and the effect of antiplatelet therapy in Kawasaki disease (KD). The aim of this study was to clarify platelet activation dynamics in acute-phase KD patients by assaying platelet-derived microparticles (PDMPs).

METHODS AND RESULTS

The PDMP level in 18 patients with acute KD was measured on ELISA. Of the 18 patients, 14 were receiving oral aspirin and i.v. immunoglobulin (IVIG) and 4, oral aspirin alone. Blood samples were drawn before, immediately after, and 10-14 days after IVIG infusion; thereafter, at 1, 2, and 3 months after the onset of disease. PDMP level before aspirin treatment was significantly higher in acute-phase KD patients than in the control subjects with common febrile diseases (P<0.01). In the acute-phase KD patients, IVIG significantly decreased PDMP level; the PDMP level was not lower on the similar day of KD in the patients who did not receive IVIG. Eight patients' PDMP level rebounded after aspirin was discontinued.

CONCLUSIONS

Platelets are activated during acute-phase KD, which confirms the importance of antiplatelet therapy. In addition, platelet activation continues as long as 2 or 3 months after the acute phase, the time at which aspirin is commonly discontinued, and the timing of aspirin discontinuation should therefore be evaluated in each individual patient.

Aliskiren, a direct renin inhibitor, improves vascular endothelial function in patients on hemodialysis independent of antihypertensive effect ∼ a pilot study∼

AIMS

Aliskiren inhibits the first step in the renin-angiotensin system (RAS) and recently has been shown to modulate vascular diseases via RAS-dependent and independent pathways. This study aimed to determine the effect of aliskiren-associated direct renin inhibition on endothelial function in patients on hemodialysis via flow-mediated dilatation (FMD) and platelet-derived microparticles (PDMP), as biomarkers of atherosclerosis.

METHODS

A 12-week prospective study was performed with 24 patients on hemodialysis who were administered 150 mg orally aliskiren once daily for 12 weeks.

RESULTS

No significant difference were observed between pre-dialysis, home, and weekly averaged blood pressure at baseline and at 12 weeks (151.5 ± 8.5/80.9 ± 12.9 mmHg vs 150.3 ± 15.3/78.9 ± 21.2 mmHg, 151.4 ± 9.7/82.3 ± 14.7 mmHg vs 151.2 ± 17.7/81.4 ± 10.6 mmHg, and 156.0 ± 18.3/81.9 ± 9.4 mmHg vs 152.5 ± 18.9/81.7 ± 12.3 mmHg, respectively). FMD significantly increased from 2.54% ± 1.45% at baseline to 3.11% ± 1.37% at 12 weeks (P = 0.0267), and PDMP significantly decreased from 13.9 ± 5.8 U/mL at baseline to 10.9 ± 4.5 U/mL at 12 weeks (P = 0.0002).

CONCLUSION

Aliskiren improved vascular endothelial function and platelet-endothelium activation in patients on hemodialysis independent of antihypertensive effect.

Extracellular vesicles in physiological and pathological conditions

Body fluids contain surprising numbers of cell-derived vesicles which are now thought to contribute to both physiology and pathology. Tools to improve the detection of vesicles are being developed and clinical applications using vesicles for diagnosis, prognosis, and therapy are under investigation. The increased understanding why cells release vesicles, how vesicles play a role in intercellular communication, and how vesicles may concurrently contribute to cellular homeostasis and host defense, reveals a very complex and sophisticated contribution of vesicles to health and disease.

Determination of the size distribution of blood microparticles directly in plasma using atomic force microscopy and microfluidics

Microparticles, also known as microvesicles, found in blood plasma, urine, and most other body fluids, may serve as valuable biomarkers of diseases such as cardiovascular diseases, systemic inflammatory disease, thrombosis, and cancer. Unfortunately, the detection and quantification of microparticles are hampered by the microscopic size of these particles and their relatively low abundance in blood plasma. The use of a combination of microfluidics and atomic force microscopy to detect microparticles in blood plasma circumvents both problems. In this study, capture of a specific subset of microparticles directly from blood plasma on antibody-coated mica surface is demonstrated. The described method excludes isolation and washing steps to prepare microparticles, improves the detection sensitivity, and yields the size distribution of the captured particles. The majority of the captured particles have a size ranging from 30 to 90 nm, which is in good agreement with prior results obtained with microparticles immediately isolated from fresh plasma. Furthermore, the qualitative shape of the size distribution of microparticles is shown not to be affected by high-speed centrifugation or the use of the microfluidic circuit, demonstrating the relative stable nature of microparticles ex vivo.

Hemocompatibility of Inorganic Physical Vapor Deposition (PVD) Coatings on Thermoplastic Polyurethane Polymers

Biocompatibility improvements for blood contacting materials are of increasing interest for implanted devices and interventional tools. The current study focuses on inorganic (titanium, titanium nitride, titanium oxide) as well as diamond-like carbon (DLC) coating materials on polymer surfaces (thermoplastic polyurethane), deposited by magnetron sputtering und pulsed laser deposition at room temperature. DLC was used pure (a-C:H) as well as doped with silicon, titanium, and nitrogen + titanium (a-C:H:Si, a-C:H:Ti, a-C:H:N:Ti). In-vitro testing of the hemocompatibility requires mandatory dynamic test conditions to simulate in-vivo conditions, e.g., realized by a cone-and-plate analyzer. In such tests, titanium- and nitrogen-doped DLC and titanium nitride were found to be optimally anti-thrombotic and better than state-of-the-art polyurethane polymers. This is mainly due to the low tendency to platelet microparticle formation, a high content of remaining platelets in the whole blood after testing and low concentration of platelet activation and aggregation markers. Comparing this result to shear-flow induced cell motility tests with e.g., Dictostelium discoideum cell model organism reveals similar tendencies for the investigated materials.

Platelet proteomics: state of the art and future perspective

Platelets pose unique challenges to cell biologists due to their lack of nucleus and low levels of messenger RNA. Platelets cannot be cultured in great abundance or manipulated using common recombinant DNA technologies. As a result, platelet research has lagged behind that of nucleated cells. The advent of mass spectrometry and its application to protein biochemistry brought with it great hopes for the platelet community that are now being realized. This technology is ideally suited for identifying low-abundance proteins, protein-protein interactions, and post-translational modifications in complex protein mixtures. Over the past 10 years, proteomics has delivered in many ways, providing platelet biologists with a comprehensive list of proteins expressed in platelets, information on post-translational modifications, protein interactions and sub-cellular localization. Several novel and important platelet membrane proteins, including CLEC-2, CD148, G6b-B, G6f, and Hsp47, have been identified using proteomics-based approaches. New, more sensitive instrumentation and novel approaches are making it increasingly possible to identify ever lower amounts of proteins. In this chapter we highlight some of the major achievements of platelet proteomics to date, discussing challenges and how they were overcome. We also discuss new frontiers and applications of proteomics to platelets and microparticles in health and disease, as we strive to better understand the molecular mechanisms underlying the platelet response to vascular injury.

Plasma levels of platelet-derived microparticles in patients with obstructive sleep apnea syndrome

AIM

Obstructive sleep apnea syndrome (OSAS) has been associated with high cardiovascular morbidity and mortality, and patients suffer from repeated episodes of hypoxia. Platelet-derived microparticles (PDMPs) are released via platelet activation by various agonists, including inflammatory cytokines or high shear stress. Plasminogen activator inhibitor -1 (PAI-1) is a fibrinolytic marker and soluble fibrin (SF) is a coagulation activation marker. We examined plasma levels of PDMPs, PAI-1 and SF in patients with OSAS. We also examined the effects of continuous positive airway pressure (CPAP) on plasma levels of PDMPs.

METHODS

Full polysomnography (PSG) monitoring was performed on 27 patients. The apneahypopnea index (AHI) of 5 events/h or less than 30 events/h indicated mild to moderate OSAS, and an AHI of 30 events/h or more indicated severe OSAS. Plasma levels of PDMPs were measured using an ELISA kit, and PAI and SF were determined by a latex immunoassay. In addition, the effects of CPAP treatment were studied in 7 patients.

RESULT

The plasma level of PDMPs was significantly higher in patients with severe OSAS (15.8±10.4 U/mL) than normal controls (10.8±7.1 U/mL, p < 0.05) and patients with mild to moderate OSAS (9.2±3.5 U/mL, p < 0.05). The plasma levels of PDMPs correlated with the AHI (r = 0.39, p < 0.05). In addition, CPAP treatment decreased the plasma level of PDMPs (11.9±5.6 U/mL to 6.7±3.2 U/mL, p < 0.05).

CONCLUSIONS

Patients with OSAS might be at increased cardiovascular risk due to elevated PDMPs. Moreover a decrease in the plasma level of PDMPs by treatment with CPAP might reduce cardiovascular risk.

Effects of miglitol in platelet-derived microparticle, adiponectin, and selectin level in patients with type 2 diabetes mellitus

Background:

Platelet-derived microparticles (PDMP), selectins, and adiponectin play an important role in the development of atherosclerosis in diabetes. Miglitol has been shown to have a beneficial effect on postprandial hyperglycemia in diabetic patients. However, its influence on platelet activation markers (PDMP and soluble CD40 ligand [sCD40L]), selectins, and adiponectin in these patients is poorly understood.

Aim:

We investigated the effect of miglitol on circulating levels of PDMP, sCD40L, selectins, and adiponectin in patients with type 2 diabetes.

Methods:

Miglitol (150 mg/day) was administered for 4 months. Levels of PDMP, sCD40L, soluble P-selectin (sP-selectin), soluble E-selectin (sE-selectin), soluble L-selectin (sL-selectin), and adiponectin were measured by enzyme-linked immunosorbent assay at baseline, and after 1 and 4 months of treatment.

Results:

The levels of PDMP, sCD40L, sP-selectin, sE-selectin, and sL-selectin were higher in diabetic patients than in hypertensive patients, while there were no significant differences between hypertensive and hyperlipidemic patients. Before miglitol treatment, the adiponectin level of diabetic patients was lower than that of hypertensive patients. Miglitol therapy significantly decreased the plasma PDMP and sCD40L levels relative to baseline. Miglitol also caused a significant decrease of sP-selectin, sE-selectin, and sL-selectin. On the other hand, miglitol therapy led to a significant increase in adiponectin after 4 months of administration compared with baseline. Furthermore, the reduction of platelet activation markers and selectins during miglitol therapy was significantly greater in the responder (adiponectin-improved) group than the nonresponder group of diabetic patients.

Conclusion:

Miglitol has an adiponectin-dependent anti-atherothrombotic effect that may be beneficial for primary prevention of atherothrombosis in patients with type 2 diabetes.