Effects of platelets on characteristics of lymphocytes cultured in vitro and optimization of adoptive immunotherapy

T lymphocytes,the main participants of cellular immunity,can express a variety of surface molecules and form different lymphocyte subsets under the induction of different factors to play the functions of immune regulation and immune killing.Studies have shown that platelets play a crucial role in maintaining the stable differentiation of lymphocytes and the balance in immunomodulation.Therefore,it is necessary to study the effect of platelets on lymphocytes in vitro to better understand the role of platelets in the immune system and broaden the application of adoptive immunotherapy.Methods:Cell counting and microscopic observation were used to detect the effect of activated platelets on lymphocyte proliferation in vitro;Flow cytometry was used to detect whether changes in platelet activity affect the proportion of lymphocyte subpopulations in vitro,and to detect differences in the expression of granzyme B;lactate dehydrogenase assay(LDH)was used to determine the difference in lymphocyte killing activity caused by platelet activity in vitro.Results:This was the first to promote lymphocyte proliferation through the expression or release of certain molecules in vitro,demonstrating that platelet activation is one of the key factors.Secondly,activated platelets or inactivated platelets promoted lymphocyte subset differentiation by enhancing the proportion of CD3+CD8+T lymphocytes(CTL cells)but had a slight effect on the proportion of CD3+CD4+T(Th cells)and CD4+CD25+T lymphocytes(Treg cells).Then,it was found that either activated platelets or inactivated platelets down-regulated the proportion of natural killer(NK)T lymphocytes,while activated platelets significantly enhance the proportion of NK lymphocytes.Therefore,by further detecting the killing activity of PBMCs treated with platelets,it was found that activated platelets promoted the extensive anti-tumor activity of lymphocytes and significantly increased the expression of granzyme B.Conclusion:Our results suggest that activated platelets promote lymphocyte proliferation,optimize lymphocyte subpopulation ratio,and promote cytotoxic effect of lymphocytes in vitro,which may provide a new strategy for optimizing the adoptive immunotherapy culture system and improving its efficacy.

Platelets Play an Integral Role in Body Heat Production and Maintenance: A Newly Proposed Function

In platelets, most of the ADP is stored in dense granules and released into extracellular space through exocytosis as a signaling molecule upon platelet activation. Glycolysis and the TCA cycle consume considerable amounts of ADP;however, limiting quantities of available ADP to make ATP through OXPHOS result in failure of ATP production and release of energy as heat into the surroundings. Thus, body heat may be a potential product of circulating platelets. Furthermore, the incomplete OXPHOS process causes the production of ROS that leads to earlier platelet death resulting in shorter life span. In the future, this new function may have a wide variety of clinical applications.

Evaluation of the diagnostic value of total bile acids/platelets in HBV related liver fibrosis

Objective:Explore the diagnostic value of total bile acids/platelets in HBV related liver fibrosis.Methods:160 patients with chronic HBV infection admitted to the Infection Department of the First Affiliated Hospital of Hainan Medical College from February 2021 to December 2022 were selected.They were divided into two groups based on the degree of liver fibrosis detected by liver biopsy:significant liver fibrosis group and non-significant liver fibrosis group.The total bile acid/blood platelet levels and their correlation with liver fibrosis in the two groups were compared and observed,and the efficacy of other non-invasive liver fibrosis diagnostic models was evaluated.Results:(1)Compared with the non-significant liver fibrosis group,the significant liver fibrosis group showed an increase in total bile acid levels,a decrease in platelet levels,and a significant increase in total bile acid/platelet levels(P<0.05).(2)Platelets decrease with the increase of liver fibrosis degree,total bile acids increase with the increase of liver fibrosis degree,and total bile acids/platelets increase with the increase of liver fibrosis degree.(3)The area under the curve(AUC)of total bile acid/platelet,APRI,FIB-4,and elastography in diagnosing the degree of liver fibrosis were 0.69,0.57,0.56,and 0.68,respectively.Conclusions:The diagnostic efficacy of total bile acids/platelets in diagnosing HBV related liver fibrosis is no less than that of other liver fibrosis diagnostic methods,and it is non-invasive,simple,and convenient,which is worthy of further clinical promotion and validation.

Platelets in hemostasis and thrombosis:Novel mechanisms of fibrinogen-independent platelet aggregation and fibronectin-mediated protein wave of hemostasis

Platelets are small anucleate cells generated from megakaryocytes in the bone marrow. Although platelet genera- tion, maturation, and clearance are still not fully understood, significant progress has been made in the last 1-2 dec- ades. In blood circulation, platelets can quickly adhere and aggregate at sites of vascular injury, forming the platelet plug （i.e. the first wave of hemostasis）. Activated platelets can also provide negatively charged phosphatidylserine- rich membrane surface that enhances cell-based thrombin generation, which facilitates blood coagulation （i.e. the second wave of hemostasis）. Platelets therefore play central roles in hemostasis. However, the same process of hemostasis may also cause thrombosis and vessel occlusion, which are the most common mechanisms leading to heart attack and stroke following ruptured atherosclerotic lesions. In this review, we will introduce the classical mechanisms and newly discovered pathways of platelets in hemostasis and thrombosis, including fibrinogen-inde- pendent platelet aggregation and thrombosis, and the plasma fibronectin-mediated ＂protein wave＂ of hemostasis that precedes the classical first wave of hemostasis. Furthermore, we briefly discuss the roles of platelets in inflam- marion and atherosclerosis and the potential strategies to control atherothrombosis.

Platelets and depression in cardiovascular disease:A brief review of the current literature

Major depression is an independent risk factor for cardiovascular mortality and morbidity. The exact mechanisms linking depression and increased cardiovascular risk remain poorly understood. Several mechanisms have been proposed including increased platelet reactivity. This review focuses on the current literature that examines the platelet hypothesis of depression. To date studies show increased serotonin response, increased platelet serotonin receptor density, decreased serotonin transporter binding, and decreased platelet serotonin levels in individuals with depression. However other studies have shown no change in serotonin uptake. In addition to platelet serotonin specific pathways, other platelet pathways that have shown significant changes in depressed individuals include blunting of the platelet adenosine response, increased platelet thrombin response, increased glycoprotein Ⅰb expression, increased P-selectin, β thromboglobulin, and platelet factor four, as well as decreased platelet brain derived neurotrophic factor. However there are other studies that show conflicting evidence of increased platelet activation as measured by integrin receptor α2b β3. Other conflictingdata include α adrenergic density and platelet response to augmented serotonin. The direction of future research in platelet functional changes in depression and coronary artery disease should continue to focus on serotonin specific pathways with emphasis on potential mechanisms of specific pathway changes.

Multipotent role of platelets in inflammatory bowel diseases:A clinical approach

There is evidence that inflammatory bowel diseases (IBD) combine both inflammation and coagulation in their pathogenesis and clinical manifestations. Although platelets (PLT) are well known for their role in hemostasis, there are a rising number of studies supporting their considerable role as inflammatory amplifiers in chronic inflammatory conditions. IBD are associated with several alterations of PLT, including number, shape, and function, and these abnormalities are mainly attributed to the highly activated state of circulating PLT in IBD patients. When PLT activate, they increase in size, release a great variety of bio-active inflammatory and procoagulant molecules/particles, and express a variety of inflammatory receptors. These inflammatory products may represent a part of the missing link between coagulation and inflammation, and can be considered as possible IBD pathogenesis instigators. In clinical practice, thrombocytosis is associated both with disease activity and iron deficiency anemia. Controlling inflammation and iron replacement in anemic patients usually leads to a normalization of PLT count. The aim of this review is to update the role of PLT in IBD and present recent data revealing the possible therapeutic implications of anti-PLT agents in future IBD remedies.

Hexagonal hematite platelets synthesized from pyrite cinders by hydrothermal process

Well-crystallized hexagonal hematite （α-Fe2O3） platelets were synthesized by hydrothermal process, using a highly concentrated ferric hydroxide as precursor. The precursor was prepared by adding ammonia to the ferric sulfate solution which was obtained by leaching pyrite cinders with sulfuric acid. Structure and morphology of the synthesized products were investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope and selected area electron diffraction. The results reveal that the reaction temperature has significant effects on the structure, size and shape of the synthesized hematite particles. Typical hexagonal hematite platelets, about 0.4-0.6 μm in diameter and 0.1 μm in thickness, were prepared at 230 ℃ for 0.5 h. Al^3＋, contained in the sulfuric acid leaching solution as an impurity, plays an extremely important role in the formation of hexagonal hematite. In addition, a possible mechanism about the formation of hexagonal hematite platelets was proposed.

Preparation of sol-gel derived microcrystalline corundum abrasives with hexagonal platelets

The effects of different additives on the mechanical properties, microstructures, and wear behavior of corundum abra- sives were investigated. When the number of additive phases increases, the sintering temperature and wear rate decrease, while the densification and mechanical properties increase. The additive SiO2 is responsible for the development of equiaxed grains, whereas both CaO and MgO promote the development of platelike grains. By controlling the molar ratio of additives, it is pos- sible to obtain different microstructures. With SiO2-MgO-CaO （molar ratio, 2：1：1） as the additives and nano a-Al203 powders as the seed, microcrystalline corundum abrasives with hexagonal platelets were obtained using sol-gel process by sintering at 1300℃ for 0.5 h. The average diameter and thickness of hexagonal platelets are 1.38 μm and 360 nm respectively, the sin- gle-particle compressive strength is 26.44 N, and the wear rate is （3.06±=0.21）× 10^-7 mm^3/（N.m）.

Role of platelets and breast cancer stem cells in metastasis

The high mortality rate of breast cancer is mainly caused by the metastatic ability of cancer cells,resistance to chemotherapy and radiotherapy,and tumor regression capacity.In recent years,it has been shown that the presence of breast cancer stem cells is closely associated with the migration and metastatic ability of cancer cells,as well as with their resistance to chemotherapy and radiotherapy.The tumor microenvironment is one of the main molecular factors involved in cancer and metastatic processes development,in this sense it is interesting to study the role of platelets,one of the main communicator cells in the human body which are activated by the signals they receive from the microenvironment and can generate more than one response.Platelets can ingest and release RNA,proteins,cytokines and growth factors.After the platelets interact with the tumor microenvironment,they are called"tumor-educated platelets."Tumor-educated platelets transport material from the tumor microenvironment to sites adjacent to the tumor,thus helping to create microenvironments conducive for the development of primary and metastatic tumors.It has been observed that the clone capable of carrying out the metastatic process is a cancer cell with stem cell characteristics.Cancer stem cells go through a series of processes,including epithelial-mesenchymal transition,intravasation into blood vessels,movement through blood vessels,extravasation at the site of the establishment of a metastatic focus,and site colonization.Tumor-educated platelets support all these processes.

Preoperative maximal voluntary ventilation,hemoglobin,albumin,lymphocytes and platelets predict postoperative survival in esophageal squamous cell carcinoma

BACKGROUND Preoperative pulmonary function plays an important role in selecting surgical candidates and assessing postoperative complications.Reduced pulmonary function is associated with poor survival in several cancers,but the prognostic value of preoperative pulmonary function in esophageal squamous cell carcinoma(ESCC)is unclear.Nutritional and systemic inflammation parameters are vital to cancer survival,and the combination of these parameters improves the prognostic value.The hemoglobin,albumin,lymphocytes and platelets(HALP)score is a novel prognostic indicator to reflect the nutritional and inflammation status,but the clinical effects of the HALP score combined with maximal voluntary ventilation(MVV),an important parameter of pulmonary function,have not been well studied in ESCC.AIM To investigate the prognostic value of MVV and HALP score for assessing postoperative survival of ESCC patients.METHODS Data form 834 ESCC patients who underwent radical esophagectomy with R0 resection were collected and retrospectively analyzed.Preoperative MVV and HALP data were retrieved from medical archives.The HALP score was calculated by the formula:Hemoglobin(g/L)×albumin(g/L)×lymphocytes(/L)/platelets(/L).The optimal cut-off values of MVV and HALP score were calculated by the receiver operating characteristic curve analysis.The Kaplan-Meier method with log-rank test was used to draw the survival curves for the variables tested.Multivariate Cox proportional hazard regression models were used to analyze the independent prognostic factors for overall survival.RESULTS MVV was significantly associated with gender(P<0.001),age at diagnosis(P<0.001),smoking history(P<0.001),drinking history(P<0.001),tumor length(P=0.013),tumor location(P=0.037)and treatment type(P=0.001).The HALP score was notably associated with gender(P<0.001),age at diagnosis(P=0.035),tumor length(P<0.001)and invasion depth(P=0.001).Univariate Cox regression analysis showed that low MVV and low HALP score were associated with worse overall survival(all P<0.001).Multivariate analysis showed that low MVV and the HALP score were both independent risk factors for overall survival(all P<0.001).The combination of MVV and HALP score improved the prediction performance for overall survival than tumor-node-metastasis.Also,low combination of MVV and HALP score was an independent risk factor for poor overall survival(P<0.001).CONCLUSION MVV,HALP score and their combination are simple and promising clinical markers to predict overall survival of ESCC patients.

Platelets:A possible glance into brain biological processes in schizophrenia

Schizophrenia is a severe mental disorder, characterized by behavioral, emotional and cognitive disturbances,which commonly follows a chronic course. Diagnostic accuracy, management plans, treatment evaluation and prognosis are dependent on relatively subjective assessments. Despite extensive research and improvement in imaging technology, as well as modern genetic and molecular methodologies, the biological basis of this disease is still unclear. Therefore, there is a need for objective and valid biological markers. Platelets have often been used as a model in neurobiological research. The accessibility of platelets and their similarities with neurons turns them into an attractive candidate to search for biological markers for diagnosis and for unraveling pathophysiological processes relevant to the etiology of brain disorders, including schizophrenia.The present review addresses the main changes in platelet physiology observed in schizophrenia and its response to antipsychotic medication. We summarize numerous studies demonstrating impaired metabolism,uptake and receptor kinetics of schizophrenia-relevantneurotransmitters, abnormalities in membrane derived phospholipids and polyunsaturated fatty acids, as well as dysfunctions in the mitochondria. These changes fit with the various hypotheses raised for the etiology of schizophrenia, including the dopamine-glutamate hypothesis, the autoimmune hypothesis, the polyunsaturated fatty acid hypothesis and the impaired energy metabolism hypothesis. Despite extensive research in platelets, no conclusive reliable biomarker has been identified yet. This review suggests that the clinical heterogeneity and the biological complexity of schizophrenia lead to the inevitable conclusion that biomarkers will be identified only for subgroups characterized according to the different diagnostic criteria. Moreover, any biomarker would have to be an array of interrelated factors or even a set of several such arrays.

Tumor-infiltrating platelets predict postoperative recurrence and survival in resectable pancreatic neuroendocrine tumor

BACKGROUND Platelets have been reported to participate in tumor cell growth,extravasation,epithelial–mesenchymal transition,metastasis,and drug resistance.However,the importance of platelets in pancreatic neuroendocrine tumor(pNET)lacks adequate literature support.The predictive value of tumor-infiltrating platelets(TIPs)in pNET remains unclear.AIM To investigate the relationship between TIPs and the prognosis of patients with pNET following radical resection.METHODS In total,113 patients who had undergone radical surgical resection with a pathologic diagnosis of pNET were enrolled in this study.Immunohistochemical analysis of cluster of differentiation 42b(CD42b)expression in the tumor specimens was performed to determine the presence of TIPs.Univariate and multivariate analyses were used to analyze the prognostic value of TIPs.RESULTS TIPs were observed in intratumoral areas in 54 patients.Neither basic characteristics nor preoperative platelet-associated indicators showed a significant relationship with the presence of TIPs(all P>0.05).Patients with positive intratumoral CD42b expression had worse overall survival(P=0.005)and recurrence-free survival(P<0.001)than those with negative intratumoral CD42b expression.Multivariate analysis demonstrated that TIPs were independent prognostic factors for overall survival(P=0.049)and recurrencefree survival(P=0.003).Nevertheless,platelet count,mean platelet volume,and platelet-to-lymphocyte ratio were not associated with postoperative survival or recurrence in pNET patients(all P>0.05).CONCLUSION TIPs are a useful prognostic biomarker for patients with resectable pNET,and their detection represents a promising tool for pNET treatment strategy decisions.

A comparative study of polymer nanocomposites containing multi-walled carbon nanotubes and graphene nanoplatelets

Featuring exceptional mechanical and functional performance, MWCNTs and graphene(nano)platelets(GNPs or Gn Ps;each platelet below 10 nm in thickness) have been increasingly used for the development of polymer nanocomposites. Since MWCNTs are now cost-effective at US$30 per kg for industrial applications, this work starts by briefly reviewing the disentanglement and surface modification of MWCNTs as well as the properties of the resulting polymer nanocomposites. GNPs can be made through the thermal treatment of graphite intercalation compounds followed by ultrasonication;GNPs would have lower cost yet higher electrical conductivity over 1,400 S cmthan MWCNTs. Through proper surface modification and compounding techniques, both types of fillers can reinforce or toughen polymers and simultaneously add anti-static performance. A high ratio of MWCNTs to GNPs would increase the synergy for polymers. Green, solvent-free systhesis methods are desired for polymer nanocomposites. Perspectives on the limitations, current challenges and future prospects are provided.

Effect of Lithium Nitrate on the Structure and Property of α-Al2O3 Platelets Prepared via Solid-state Reaction

The α-Al_2O_3 platelets were prepared via solid-state reactions and the effect of the amount of lithium nitrate additive on the property of the platelets was investigated. The ICP results indicated that the high temperature calcination process resulted in a large loss of lithium species because of volatilization, but there was still a small amount of residual lithium species in the α-Al_2O_3 platelets. The SEM micrographs showed that lithium nitrate led to decrease in the thickness of α-Al_2O_3 platelets and irregular morphology of aggregates. Pore structures results exhibited that addition of lithium nitrate led to decrease in the pore size and increase in the specific surface area of aggregates of α-Al_2O_3 platelets. The XRD and IR patterns suggested that the residual lithium and aluminum oxide formed LiAl_5O_8. The existence of LiAl_5O_8 was the basic reason for the changed performance of α-Al_2O_3 platelets.

Preparation and Characterization of Bi_4Ti_3O_(12) Platelets by a Novel Low-temperature Molten Salt System

Bismuth titanate （Bi4Ti3O12） platelets were prepared by molten salt method in a new salt system of CaCl2·NaCl at 650-750℃, using bismuth nitrate pentahydrate （Bi （NO3）3·H2O） and titanium butoxide （Ti （OC4H9）4） as raw materials. The synthesis temperature of Bi4Ti3O12 platelets was decreased to 650℃ from 900-1100℃. The phase compositions and crystalline morphology of Bi4Ti3O12 platelets were investigated by XRD and SEM. The experimental results indicate that Bi4Ti3O12 platelets containing tetragonal and orthorhombic phase with the size of 1-3μm can be synthesized at 650℃ for 2 h, and the orthorhombic phase becomes the dominant phase at 750℃ for 5 h. The size and proportion of Bi4Ti3O12 platelets increase with the increment of the calcining temperature and holding time. The proportion of platelets increases to about ninety percent, and the platelets grow up to about 3-10μm at 750℃ for 5 h from 1-2μm at 650℃ for 2 h. This technical route provides a new low-temperature molten salt system for preparing platelets by molten salt methods.

Platelets Levels before and after Surgical Intervention in Patients with Oral and Maxillofacial Tumors at MNH, Tanzania

Background: There are documented effects of platelets on the solid tumors which need further study. The elevated platelet counts have been described for majority of cancers. There is inadequate information of effect of benign and malignant oral and maxillofacial tumors on the regulation of platelets. The aim of this study was to investigate the changes in platelet counts among patients with oral and maxillofacial benign and malignant tumors following surgical interventions. Methods: A descriptive postoperative study was done whereby patients with benign and malignant oral and maxillofacial tumors who met the inclusion criteria were included. The included patients were those who had no history of blood transfusion prior, during or after surgery, not on haemoglobin-boosting or bone marrow suppressing medications, not seropositive to human immunodeficiency virus also without clinical findings suggestive of lymphadenopathy, splenomegaly, ecchymosis and petechiae. Demographic data, Platelet counts and haemoglobin levels before and after surgery were documented and analysed by chi-square test and values were considered to be significant if p < 0.05. Results: A total of 61 patients were included in the study. The mean age of participants was 37.03 ± 16.6 years with range of 7 to 77 years. Majority 82.5% (n = 52) had benign tumors with a leading diagnosis of ameloblastoma followed by ossifying fibroma. In general there was an increase of platelet counts following surgery from the mean of 276.38 ± 109.40 K/uL to 308.51 ± 117.24 K/uL. Looking at benign and malignant separately, following surgery there was an increase of platelet counts for benign tumors (278.87 ± 106.37 to 305.96 ± 123.12) but a decrease for malignant tumors group (282.33 ± 147.03 to 232 ± 78.48). The haemoglobin level changed from the mean of 12.60 ± 1.71 g/dl before surgery to 11.69 ± 1.70 g/dl after surgery. Conclusion: The mean postoperative increase in platelet counts in benign and malignant tumors was due to healing process of the wound following surgery while the postoperative decrease in platelets counts in malignant tumors was due to effect of tumor removal which diminished the production of platelets activating factors. Malignant tumors produce platelets activating factors which are necessary for them to grow. Also, the difference in postoperative platelets counts in benign and malignant oral and maxillofacial tumors could be attributed by different biological behavior of benign and malignant tumors and hence different interactions of platelets to these tumors.

Predictive Values of Platelets Count and Spleen Diameter in the Diagnosis of Esophageal Varices in Black African Cirrhotic Patients

Background: Gastrointestinal hemorrhage from ruptured esophageal varices is of concern in Africa where gastrointestinal fibroscopy for diagnosis is lacking. Purpose: To determine the performance of the length of the spleen, of the platelet count in the diagnosis of esophageal varices (OVs) by specifying the diagnostic thresholds in order to facilitate the prophylaxis of varicose hemorrhages in black African cirrhotic patients. Material and Method: This was a prospective study with a descriptive and analytical aim on cirrhotic patients hospitalized at the university hospital of Bouake (Ivory Coast) from 2017 to 2019. The patients included in the study were the cirrhotic of black race hospitalized having carried out an abdominal ultrasound with measurement of the spleen diameter (SD), an eso-gastro-duodenal endoscopy, and a blood count with platelet count (PC). The first primary endpoint was the diagnosis of esophageal varices in cirrhosis. Cirrhosis was retained by the combination of clinical, biological, ultrasound and endoscopic arguments. The OVs were distributed according to size and the presence of red signs. The platelet count, and the measurement of the spleen to calculate the PC/SD ratio were the second endpoint. The secondary endpoints studied were, the viral and ethyl etiologies of the cirrhosis, the Chlid-Pugh prognostic score. Performance was assessed using the ROC curve. The difference was significant for p less than 0.05. Results: The study included 101 patients;they were 79 men (78.2%) and 22 women (21.8%). The mean age of the cirrhotic patients was 48 ± 14. Esophageal varices were present in (n = 93;92%) of cases. The different etiologies were hepatitis B virus (HBV) (n = 65;78.3%), hepatitis C virus (HCV) (n = 21;25, 3%), and alcohol (n = 6;7.2%). Platelet count (PC) < 100,000/mm3 was statistically related to the presence of OV with red signs. Splenomegaly (SD > 130 mm) and PC/SD ratio < 1000 were significantly related to the presence of OVs and large OVs. SD with a cutoff of > 102 mm predicted 75% of OVs (AUROC = 0.797). CP with a cutoff < 131,000/mm3, predicted 100% of OVs (AUROC = 0.756). The PC/SD ratio < 1205 diagnosed 100% of OV (AUROC = 0.801). The PC/SD ratio < 818 and SD > 129 mm predicted large OVs. Conclusion: Platelet count, spleen diamater, and PC/SD ratio were all performant for the diagnosis of OVs in our setting with better diagnostic performance for PC/SD. This report could help initiate prophylactic treatment for OVs rupture in cirrhotic patients in health centers where gastrointestinal endoscopy is lacking.

Nonlinear free vibration of graphene platelets reinforced composite corrugated plates

The nonlinear vibration of graphene platelets reinforced composite corrugated(GPRCC)rectangular plates with shallow trapezoidal corrugations is investigated.Since graphene platelets are prone to agglomeration,a multi-layer distribution is adopted here to match the engineering requirements.Firstly,an equivalent composite plate model is obtained,and then nonlinear equations of motion are derived by the von Kármán nonlinear geometric relationship and Hamilton’s principle.Afterwards,the Galerkin method and harmonic balance method are used to obtain an approximate analytical solution.Results show that the unit cell half period,unit cell inclination angle,unit cell height,graphene platelet dispersion pattern and graphene platelet weight fraction and geometry play important roles in the nonlinear vibration of the GPRCC plates.

Effects of ethanol on the properties of platelets and endothelial cells in model experiments

AIM: To investigate effects of ethanol on activity markers of atherosclerosis in an in vitro endothelial cell model. METHODS: After 24 h incubation with ethanol (0.0095%), human umbilical vein endothelial cells were stimulated for 1 h with lipopolysaccharide, and were then incubated in direct contact with activated platelets. Following this incubation, the expression of CD40L and CD62P on platelets, and the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), urokinase plasminogen activator receptor (uPAR), and membrane-type 1 matrix metalloproteinase (MT1-MMP) on endothelial cells were measured by flow cytometry. RESULTS: The increased expression of VCAM-1 and uPAR on endothelial cells by proinflammatory stimulation with activated platelets was significantly reduced through pre-incubation with ethanol (P < 0.05). Furthermore, platelets in direct contact with ethanol and with endothelial cells pre-incubated in ethanol showed a significant reduction in their CD40L expression (P < 0.05). Ethanol had no significant effect on ICAM-1 and MT1-MMP expression on endothelial cells. CONCLUSION: Ethanol directly attenuates platelet activation and has significant endothelial cell-mediated effects on selected markers of atherosclerosis in vitro. These findings underline possible protective effects of ethanol on atherosclerosis.

Platelets in psychiatric disorders

Several parallels exist between platelets and the brain,which make them interesting for studying the neurobiology of psychiatric disorders, such as Alzheimer's disease, depression, schizophrenia and anxiety disorders. Platelets store, secrete and process the amyloid precursor protein which is cleaved into the β-amyloid(Aβ) peptides. The accumulation of Aβ in brain(plaques)and vessels(Aβ-angiopathy) is a major hallmark in AD. Platelets contain high amounts of serotonin and a dysfunction of the serotoninergic system is involved in the development of several behavior disorders, such as depression, anxiety disorders and self aggressive disturbances. Furthermore, platelets are able to take up dopamine and express various dopamine receptors,which make them to an interesting tool to study the underlying mechanisms of schizophrenia. In summary,platelets are an interesting and easily accessible cell type to study changes related to different psychiatric disorders and platelets proteins may be useful as diagnostic biomarkers for some psychiatric disorders.