The nervous system directly regulates immunity through neurotransmitter receptors expressed on immune cells to participate in host defense and body reparation. Expression of neurotransmitter receptors on blood cells provides important evidence for a direct functional link between the nervous and hematopoietic systems. Our previous studies showed that 5-hydroxytryptamine, as a monoamine neurotransmitter, plays an important role in regulating megakaryocytopoiesis. This review summarizes recent findings of the effect of monoamine neurotransmitter on megakaryocytopoiesis and platelet function, focusing on the receptor expression on hematopoietic stem cells, megakaryocytes/platelets and their functions in order to explore the intrinsic relation of nervous system and hematopoietic system. Based on the existing research results, we find that the monoamine neurotransmitter participates in regulation of megakaryocytopoiesis, and affects on aggregation and functions activation of platelets. Moreover, it has a close link with the specific regulatory factor of megakaryocytopoiesis-TPO. Thus those results also support the "brain-bone marrow-blood-axis" viewpoint of some researchers. At present, the study of the nervous system regulating hematopoiesis is still in its infancy, the exact mechanism remains to be further studied.
Biogenic Monoamines ; physiology ; Blood Platelets ; physiology ; Humans ; Megakaryocytes ; cytology ; Neurotransmitter Agents ; physiology ; Platelet Function Tests

The aim of this study was to assess the prognostic value of combined use of white blood cell (WBC), hemoglobin (Hb), and platelet distribution width (PDW) in patients with acute myocardial infarction (AMI). This study included 1,332 consecutive patients with AMI. Patients were categorized into complete blood cell (CBC) group 0 (n=346, 26.0%), 1 (n=622, 46.7%), 2 (n=324, 24.3%), and 3 (n=40, 3.0%) according to the sum of the value defined by the cut-off levels of WBC (1, > or =14.5x10(3)/microL; 0, <14.5x10(3)/microL), Hb (1, <12.7 g/dL; 0, > or =12.7 g/dL), and PDW (1, > or =51.2%; 0: <51.2%). In-hospital death occurred in 59 (4.4%) patients. Patients who died during index hospitalization had higher WBC and PDW and lower Hb. The patients could be stratified for in-hospital mortality according to CBC group; 1.2%, 2.7%, 9.0%, and 22.5% in CBC groups 0, 1, 2, and 3 (P<0.001), respectively. In multivariate logistic regression analysis, CBC group> or =2 (odds ratio, 3.604; 95% confidence interval, 1.040-14.484, P=0.043) was an independent predictor for in-hospital death. The prognostic impact of the combined use of CBC markers remained significant over 12 months. In conclusions, combination of WBC, Hb, and PDW, a cheap and simple hematologic marker, is useful in early risk stratification of patients with AMI.
Acute Disease ; Aged ; Biological Markers/blood ; Blood Platelets/*cytology/physiology ; Female ; Hemoglobins/*analysis ; Hospital Mortality ; Humans ; Kaplan-Meier Estimate ; Leukocyte Count ; Leukocytes/*cytology ; Logistic Models ; Male ; Middle Aged ; Myocardial Infarction/*diagnosis/mortality ; Odds Ratio ; Prognosis ; Proportional Hazards Models ; ROC Curve ; Risk Factors

No abstract available.
Adult ; Aged ; Aged, 80 and over ; Blood Chemical Analysis/instrumentation ; Blood Platelets/*cytology/physiology ; Female ; Flow Cytometry/*instrumentation/standards ; Humans ; Male ; Middle Aged ; Platelet Count/*instrumentation/standards ; Reference Values ; Republic of Korea ; Young Adult

The study was aimed to investigate the potential immunotherapeutical values of umbilical cord tissue-derived mesenchymal stem cells (UC-MSC) on patients with chronic idiopathic thrombocytopenic purpura (ITP). UC-MSC was cocultured in vitro with splenocytes isolated from ITP patients who experienced splenectomy. The level of IgG antiplatelet antibody (PAIgG) was determined by a competitive micro-enzyme-linked immunosorbent assay (ELISA) method. The proliferation of platelet-reactive CD4+ T lymphocytes was also measured in the presence of UC-MSCs. The results showed that UC-MSCs could stimulate the spontaneous secretion of PAIgG in supernatants; In the platelet-inducing condition, UC-MSC inhibited the production of PAIgG at a low ratio of 1 UC-MSC to 100 splenocytes, but promoted at a high proportion of 1 UC-MSC to 10 splenocytes. Moreover, UC-MSC exerted a suppressive effect on proliferation of platelet-reactive T helper cells in a dose-dependent manner. It is concluded that the UC-MSCs can regulate secretion of antiplatelet antibodies in vitro. Its concrete regulation mechanism and potential immunotherapeutical value are need to further study.
Antibodies ; metabolism ; Blood Platelets ; immunology ; CD4-Positive T-Lymphocytes ; cytology ; Cell Proliferation ; Humans ; Infant, Newborn ; Lymphocyte Activation ; Mesenchymal Stromal Cells ; physiology ; Purpura, Thrombocytopenic, Idiopathic ; metabolism ; Spleen ; cytology ; Umbilical Cord ; physiology

The dielectric spectroscopy of human platelets was measured within the frequency range of 100 KHz-100 MHz, and the dielectric numerical characters of human platelets in response to AC electric field were analyzed. We measured the AC impedance of normal human platelets with the impedance technique in the frequency domain for the first time. The experimental data were used to draw a relationship curve between the frequency of electric field and permittivity or conductivity, and then the dielectric spectrum and the Cole-Cole plots of human platelets were established and then, the characteristics of dielectric response of human platelets were decided, which demonstrated the dependence of permittivity and conductivity of human platelets upon frequency, and showed two characteristic frequencies of the dielectric spectroscopy of human platelets: the first characteristic frequency f(C1) = 6.66 MHz; the second characteristic frequency f(C2) = 9.81 MHz.
Blood Platelets ; cytology ; physiology ; Electric Conductivity ; Electric Impedance ; Electrochemistry ; methods ; Electrophysiology ; Humans ; Spectrum Analysis ; methods

This study was aimed to compare the difference of quality between buffy-coat-collected platelet concentrates (BC-PC) and single-donor plateletpheresis (SDP). 15 packs of BC-PC and 15 units SDP were stored at 20 degrees C - 24 degrees C with agitation. Platelet concentration, platelet volume, residual leukocyte and residual erythrocyte in two groups were examined after preparation for 1 hour. Mean platelet volume, pH value, hypotonic shock response (HSR), CD62p expression and CD62p re-expression of platelet were detected on 0, 1, 2, 3, 4, 5 days of platelet preservation. The results showed that the platelet yields, residual leukocyte and residual erythrocyte in two groups accorded with the national quality standard respectively, but residual leukocyte and residual erythrocyte in BC-PC group were higher than those in SDP group when platelet yields in two groups were equal (p < 0.01). Lactate concentration, CD62p expression of platelet increased with prolongation of preseved time, while pH value decreased gradually. Compared with SDP group, there were significant differences in CD62p expression, CD62p re-expression of platelet preserved for 0 - 5 days (p < 0.01), and in pH value of platelet preserved 2 - 5 days (p < 0.01). There was no changes in HSR of SDP group for 0 - 5 days, while HSR in BC-PC group decreased gradually. There were significant differences in HSR of platelet preserved for 1 - 5 days (p < 0.01). It is concluded that the platelet concentrates prepared by BC-PC are not equal to SDP in quality, the preparation technology of BC-PC should be optimized further in order to reduce residual leukocyte, residual erythrocyte and activated platelet yields, as well as improve the quality of BC-PC.
Blood Platelets ; metabolism ; physiology ; Blood Preservation ; Cell Separation ; methods ; Erythrocytes ; cytology ; Humans ; Lactic Acid ; blood ; Leukocytes ; cytology ; P-Selectin ; blood ; Platelet Count ; Plateletpheresis ; instrumentation ; methods ; Quality Control

This study was purposed to investigate the effects of platelet-derived membrane microparticles (PMP) on the proliferation and apoptosis of human umbilical vein endothelial cells (HUVEC). Different concentrations of thrombin were adopted to activate the platelets so as to release PMPs. Flow cytometry (FCM) was adopted to evaluate the efficiencies of different concentrations of thrombin to release PMPs. By using the HUVEC cultivated in vitro as vector, the effects of PMPs on the proliferation and apoptosis of HUVEC were investigated by MTT and FCM. The results showed that the efficiencies releasing PMPs from platelets activated by 2.0, 1.5, 1.0, 0.5 U/ml thrombin were 28.7, 47.7, 50.1 and 43.9% respectively; PMPs induced proliferation of HUVEC in a dose dependent manner. At the concentration of 40 microg/ml PMPs, the proliferation rate of HUVEC was 1.8 +/- 0.3 times as much as blank control, the proliferation rate in group of vascular endothelial growth factor was 1.9 +/- 0.5 times of as much as blank control, there was no statistic difference (p > 0.05). The PMPs inhibited HUVEC apoptosis. Compared with the apoptosis rate of control (9.4 +/- 0.5)%, apoptosis rate in PMP group (40 microg/ml) was (3.9 +/- 0.4)% (p < 0.05). The addition of VEGF (10 microl/ml) did not successfully prevented apoptosis of HUVEC with apoptosis rate of (8.0 +/- 0.8)%. It is concluded that platelets activated by 1 U/ml thrombin gets the best efficiency of PMP release, which stimulates proliferation of HUVEC and inhibits its apoptosis.
Apoptosis ; drug effects ; Blood Platelets ; physiology ; Cell Proliferation ; drug effects ; Cell-Derived Microparticles ; physiology ; Cells, Cultured ; Endothelial Cells ; cytology ; Humans ; Particle Size ; Platelet Membrane Glycoproteins ; physiology ; Thrombin ; pharmacology ; Umbilical Veins ; cytology

This study was aimed to investigate the effects of DMSO on platelets during pre-treatment for lyophilization, including centrifugation, washing and loading trehalose. After pre-treatment for lyophilization, the expression of platelet membrane surface glycoprotein (GP) including CD62p and PAC-1 was analyzed by FCM before and after induction with thrombin, the mean platelet volume (MPV) and platelet maximal aggregation with several platelet inducers were investigated. The results showed that the expression rates of CD62p and PAC-1, as the platelet activation signs, increased and were 30.37% and 15.01% respectively in group without DMSO after pre-treatment. And their differences in comparison with control were statistically significant, but that of CD62p was 10.72% and PAC was 10.11% in group with DMSO, in comparison with group without DMSO respectively, their differences were statistically significant after diluting with DMSO, CD62p was re-expressed to 54.39% in group with DMSO and more than that in group without DMSO and lower than control statistically significant. PAC-1 was re-expressed to 49.28% in group with DMSO and more than that in group without DMSO (p<0.01) and reached to control. Platelet maximal aggregations induced by thrombin, restocetin and propyl gallate were 92.76%, 91.24% and 89.66 respectively in group with DMSO. These were closed to that in control group and in group without DMSO. But the aggregation induced by ADP was 34.33%, it was less than control (p<0.01) and more than that in group without DMSO (p<0.01). It is concluded that DMSO can inhibit the expression of CD62p and PAC-1 on platelet in vitro. But when diluted with plasma, platelets can express CD62p and PAC-1 induced by thrombin and be led to aggregate by several inducers, so the inhibitory effects of DMSO on platelet activation are reversible. DMSO play roles in inhibitor damage from platelet activation and cryoprotectant. This property of DMSO is very important in research of platelets lyophilization.
Blood Platelets ; cytology ; drug effects ; metabolism ; Blood Preservation ; methods ; Cell Survival ; Cryopreservation ; methods ; Cryoprotective Agents ; pharmacology ; Dimethyl Sulfoxide ; pharmacology ; Freeze Drying ; Humans ; Platelet Activation ; drug effects ; physiology ; Trehalose ; blood ; pharmacology

This study was aimed to investigate the aggregation of rehydrated-lyophilized platelets. The aggregation rate of fresh and rehydrated-lyophilized platelets were measured by using thrombin, ristocetin, ADP and collagen as inductors and APACT2 aggregameter; the effects of intra- and extra-cellular trehalose on maximum aggregation rate of rehydrated-lyophilized platelets were detected by using ADP as an inductor. The results showed that the aggregation rate of fresh platelets was all about 100%, while aggregation rate of rehydrated lyophilized platelets was (70.17 +/- 7.36)%, (15.3 +/- 2.81)%, (68.67 +/- 6.86)%, (64.67 +/- 11.6)% respectively, when the concentration of thrombin, ristocetin, ADP and collagen was 1 U/ml, 1.6 mg/ml, 20 micromol/L and 2 microg/ml. The maximum aggregation rates of rehydrated-lyophilized platelets in intra- and extra-cellular trehalose, extracellular trehalose and blank control groups were (66.0 +/- 4.69)%, (25.3 +/- 2.42)% and (11.5 +/- 1.87)% (P < 0.01), meanwhile there was significant difference of rehydrated-lyophilized platelet aggregation rate between intra- and extra-cellular trehalose and extracellular trehalose groups (P < 0.01). It is concluded that the concentrations of thrombin (1 U/ml), ristocetin (1.6 mg/ml), ADP (20 micromol/L) and collagen (2 microg/ml) are optimal for platelets aggregation tests, the internal and extracellular trehalose significantly enhance the aggregation of rehydrated-lyophilized platelets.
Blood Platelets ; cytology ; drug effects ; metabolism ; Blood Preservation ; methods ; Freeze Drying ; methods ; Humans ; Platelet Aggregation ; physiology

To investigate the effect of S-nitrosoglutathione (GSNO), a nitric oxide donor, on platelet production from megakaryocytes differentiated from cord blood CD34(+) cells in vitro, the CD34 (+) cells from eight fresh umbilical cord blood samples by a high-gradient magnetic cell sorting (MACS) system were cultured in serum-free medium for 14 d with thrombopoietin (TPO) 50 ng/ml, IL-3 10 ng/ml, stem cell factor (SCF) 50 ng/ml and rHuGM-CSF 20 ng/ml. Then, CD61 (+) cells were purified by MACS system from these CD34 (+) cells, and were cultured in serum-free medium supplemented with TPO 50 ng/ml, IL-3 10 ng/ml and SCF 50 ng/ml in the presence (treatment group) and absence (control group) of GSNO for 30 min or 2 h. Platelet-sized particles were counted by flow cytometry; megakaryocyte structure was detected by scanning electron microscope. Aggregation of the thrombin-induced platelet particle was observed under inversion microscope. cGMP was assessed by commercial ELISA kit. The results showed that, compared with the control group, the number of platelet-sized particles significantly increased (P<0.05) in the treatment group, in which megakaryocytes presented significant pseudopod formation and extensive membrane blebbing. The platelet particle aggregation could be observed under microscope after thrombin induction. cGMP activity was significantly increased after treatment with GSNO (P<0.05). These results propose that GSNO can facilitate platelet production from megakaryocyte, and it may be partly through cGMP pathway.
Antigens, CD34 ; analysis ; Blood Platelets ; cytology ; Cell Differentiation ; drug effects ; Cyclic GMP ; blood ; Female ; Fetal Blood ; cytology ; Hematopoiesis ; drug effects ; Hematopoietic Stem Cells ; cytology ; Humans ; Megakaryocytes ; cytology ; Nitric Oxide ; physiology ; Platelet Aggregation ; drug effects ; Pregnancy ; S-Nitrosoglutathione ; pharmacology