No abstract available.
Blood Platelets* ; Platelet Factor 4*

platelet factor 4 forms a PF4/heparin-immunoglobulin G immune complex on platelet surfaces. This complex activates platelets, which leads to multiple coagulation in venous and arterial blood. We report here on a rare occurrence of HIT type II following fibula free flap surgery.]]>
Antigen-Antibody Complex ; Blood Platelets ; Fibula ; Free Tissue Flaps ; Heparin ; Platelet Factor 4 ; Thrombocytopenia ; Venous Thrombosis

BACKGROUND: Dual antiplatelet therapy (aspirin and clopidogrel) is used to prevent adverse cardiac events in patients undergoing percutaneous coronary intervention (PCI). Some patients do not respond adequately to clopidogrel. Beta-thromboglobulin (beta-TG) and platelet factor 4 (PF-4) can act as markers to detect platelet activation. We investigated the relationship between clopidogrel response and the dynamics of beta-TG and PF4 concentrations. METHODS: This study included 36 myocardial infarction (MI) patients, who underwent PCI and was indicated for dual antiplatelet therapy. Platelet reactivity, using the VerifyNow P2Y12 assay, was measured on the 3rd day of PCI. At the time of admission, and on the 3rd and 10th day of PCI, the plasma beta-TG and PF4 concentrations were quantified. RESULTS: Ten patients (27.8%) were clopidogrel non-responders displaying >208 P2Y12 reaction units. At the time of admission, levels of beta-TG in patients were elevated than that in the healthy controls (P<0.001). A similar trend was observed on the 3rd and 10th day of PCI (P<0.001). The beta-TG levels on the 10th day were reduced than those at the time of admission and on the 3rd day of PCI. PF4 levels were not different between patients and controls, and were not significantly reduced after PCI. Higher beta-TG levels were observed in clopidogrel non-responders on the 10th day, but not significant. CONCLUSIONS: Clopidogrel therapy in MI reduce beta-TG concentration, but the beta-TG and PF4 levels before and after therapy are not associated with the response to clopidogrel. Platelet-derived markers may not be suitable for distinguishing clopidogrel non-responders.
beta-Thromboglobulin ; Blood Platelets* ; Humans ; Infarction* ; Myocardial Infarction ; Percutaneous Coronary Intervention ; Plasma ; Platelet Activation* ; Platelet Factor 4

OBJECTIVE: To investigate the incidence for heparin-induced thrombocytopenia (HIT) in patients undergoing cardiac surgery and to evaluate the risk factors for the generation of HIT-antibody.
 METHODS: A total of 315 patients undergoing cardiac surgery in the Department of Cardiothoracic Surgery, Xiangya Hospital between December, 2013 and July, 2014 were enrolled for this study. Among them, 120, 154 and 41 were for surgery of congenital heart defect, valve and coronary artery bypass graft, respectively. There were 170 male patients and 69 patients were under 18 years old. Platelet counts, HIT-antibody and concentration of platelet factor 4 (PF4) were tested before and after the surgery. Diagnosis of HIT was based on "4Ts" (Pretest Clinical Scoring System). 
 RESULTS: HIT was diagnosed in 11 patients (3.5%, 11/315). And thromboembolic events occurred in 2 of 11 patients with HIT. The positive ratio for HIT-antibody was 36.5% (115/315). The coronary artery disease patients had a higher incidence of HIT than that of either the valve disease or the congenital heart defect (17.1%, 7/41 versus 1.9%, 3/154 or 0.8%, 1/120; P<0.05). The congenital heart defect patients had a higher positive ratio for HIT-antibody than that of both the valve disease and the coronary artery disease. The valve disease patients had a higher positive ratio for HIT-antibody than that of the coronary artery disease (51.7%, 62/120 versus 30.5%, 47/154 versus 14.6%, 6/41; P<0.05). Major postoperative complications occurred more frequently in HIT patients (36.4%, 4/11 versus 10.5%, 32/304; P<0.05). Age was a risk factor for HIT (P=0.030, OR=1.083, 95% CI 1.008-1.163). Cardiopulmonary bypass (CPB) (P=0.037, OR=3.113, 95% CI 1.071-9.050) and age (P<0.001, OR=0.970, 95% CI 0.959-0.982) were risk factors for HIT-antibody.
 CONCLUSION The incidence of HIT is low during cardiac surgery, but HIT is a highly risk factor for the major postoperative complications. More attentions should be paid to these severe complications and the risk factors for HIT.
Antibodies ; blood ; Cardiac Surgical Procedures ; Cardiopulmonary Bypass ; Coronary Artery Bypass ; Female ; Heparin ; adverse effects ; Humans ; Incidence ; Male ; Platelet Count ; Platelet Factor 4 ; blood ; Postoperative Complications ; Risk Factors ; Thrombocytopenia ; chemically induced

Aged ; Cross Reactions ; Female ; Heparin ; adverse effects ; immunology ; Heparin, Low-Molecular-Weight ; adverse effects ; immunology ; Humans ; Male ; Middle Aged ; Platelet Factor 4 ; immunology ; Thrombocytopenia ; blood ; chemically induced ; immunology

OBJECTIVETo investigate the effects of platelet factor 4 (PF4) on the adherence, and the expressions of adherent molecules CD(49d) and CXCR4 and the receptor of SDF-1 of fresh and expanded cord blood CD(34)(+) cells.

METHODSCD(34)(+) cells were isolated from cord blood using MACS immune magnetic beads. The adherent ability was assayed by using crystal violet staining and the expression of adherent molecule CD(49d) and CXCR4 by FACS.

RESULTS(1) PF4 could increase the adherent ability of the fresh cord blood CD(34)(+) cells, the effect being positively correlated with the dose of PF4. (2) SDF-1 at concentration of 100 ng/ml increased the adherent ability of the fresh cord blood CD(34)(+) cells. (3) The spontaneous and the SDF-1 induced adherent ability of the cord blood CD(34)(+) cells began to decrease after being cultured for 10 days without PF4, while in the presence of PF4 at 100 ng/ml, the ability of the cord blood CD(34)(+) cell adhering to the stroma layer still remained at higher level. At day 14, the adherent ability was (262.04 +/- 64.81)% and (64.35 +/- 8.29)% in PF4 group and control group, respectively, if it was defined as 100% at day 0. SDF-1 at concentration of 100 ng/ml induced adherent ability was (138.31 +/- 32.39)% and (67.66 +/- 12.44)% in PF4 group and control group, respectively. (4) The expression of CD(49d) and CXCR4 increased 13.02% and 17.33%, respectively, when incubated with PF4.

CONCLUSIONSPF4 could increase the adherent ability and promote the expression of CD(49d) and CXCR4 of the cord blood CD(34)(+) cells, suggesting that PF4 promote the circulating stem cells homing to the marrow in the process of stem cells transplantation.

Antigens, CD34 ; blood ; Cell Adhesion ; drug effects ; Fetal Blood ; cytology ; Flow Cytometry ; Hematopoietic Stem Cells ; cytology ; drug effects ; Humans ; Integrin alpha4 ; blood ; Platelet Factor 4 ; pharmacology ; Receptors, CXCR4 ; blood

BACKGROUND: Heparin-induced thrombocytopenia/ thrombosis (HITT) is recognized as the most frequent and fatal symptom complexes in patients receiving heparin therapy. The antibodies of HITT are not directly bound to heparin but bound to complexes of heparin and platelet factor 4 (PF4) derived from platelet alpha-granules. That is, HITT IgG antibody-heparin-PF4 immune complexes are bound to FcgammaRII receptor of platelets, which induced thrombocytopenia. Some researches showed the antibodies reactive to platelets could be IgM or IgA as well as IgG. So in this study, the authors tried to explain the molecular basis of heparin-PF4-isoantibody complexes . METHODS: In HITT patients who had received long-term heparin therapy, we determined HITT isoantibodies and titers using heparin:PF4 ELISA. When fifteen HITT patients with high titer antibodies (more than 1 : 100) were selected, reaction patterns of isoantibodies with the platelets were examined through serotonin release test and flow cytometry. RESULTS: All patients showed one or more isotype antibodies and the most frequent isotype was IgGl (nine patients) . In the presence of optimal concentra pion of heparin and PF4, ten patients had antibodies which activated platelets, and all of them were positive in serotonin release test. Reactive plasmas had IgGl, IgG3, IgA or IgM antibodies, and each of them except one had IgGl. These platelet activations could be blocked in vitro by anti-IV.3 antibody. Non-reactive plasmas were negative In serotonin release assay nor had TgGl. The plasmas 4hat had two or more isoantibodies showed a similar pattern of the IgG antibody by flow cytometry. CONCLUSIONS: The HITT antibodies can be all kinds of antibody isotopes, but IgA and IgM may not bind to the platelets directly. It seems to be possible only after reacting with heparin-PF4-IgG complexes.
Antibodies ; Antigen-Antibody Complex ; Blood Platelets ; Enzyme-Linked Immunosorbent Assay ; Flow Cytometry ; Heparin ; Humans ; Immunoglobulin A ; Immunoglobulin G ; Immunoglobulin M ; Isoantibodies ; Isotopes ; Mesons ; Plasma ; Platelet Activation ; Platelet Factor 4 ; Serotonin ; Thrombocytopenia ; Thrombosis*

To investigate the effects of stromal cell-derived factor 1 (SDF-1) and platelet factor 4 (PF4) on the homing-related function of expanded ex vivo umbilical cord blood CD34(+) cells, purified cord blood CD34(+) cells were cultured in serum-free medium containing a HGF combination of FL + SCF + TPO (FST) with either 100 ng/ml SDF-1 alone, 100 ng/ml PF4 alone, or both of these 2 cytokines. The expansion rate of CD34(+) cells, colony formation, homing-related functions including expression of homing-related adhesion molecules of expanded CD34(+) cell, adhesion activity and chemotactic function of the re-selected expanded CD34(+) cells were evaluated at different time points. The results showed that expansion rate of CD34(+) cells and expansion multiple of CFU in SDF-1 groups were higher than those in control. The expression of CD49e on the expanded CD34(+) cells was remarkable up-regulated, in contrast, expression of CXCR-4 on the expanded CD34(+) cells was remarkable down-regulated in SDF-1 groups. The expression of CD49e, CD54 and CXCR-4 on the expanded CD34(+) cells were remarkably up-regulated in the PF4 groups. In all the SDF-1 group, PF4 group and SDF-1 plus PF4 group, the ability of expanded CD34(+) cells adhering to fibronectin layer were higher than those in the control on day 10. Spontaneous migration rate of expanded CD34(+) cells in SDF-1 groups were higher than those in control, while SDF-1-induced migration rate were lower than those in control on day 10. SDF-1-induced migration rate in PF4 groups were higher than those in control on day 10. Spontaneous and SDF-1-induced migration rate of expanded CD34(+) cells in the SDF-1 plus PF4 groups were higher than those in control on day 10. It is concluded that, SDF-1 and PF4 can up-regulate expression of adhesion molecules on expanded CD34(+) cells, and retain the adherent and migration ability of expanded CD34(+) cells, which is helpful for the homing of expanded CD34(+) cells. In short, SDF-1 and PF4 are helpful for the homing-related function of the expanded UCB HSPC.
Antigens, CD34 ; blood ; immunology ; Cell Adhesion ; drug effects ; Cells, Cultured ; Chemokine CXCL12 ; Chemokines, CXC ; pharmacology ; Chemotaxis ; immunology ; physiology ; Culture Media, Serum-Free ; Fetal Blood ; cytology ; immunology ; Hematopoietic Stem Cells ; cytology ; drug effects ; Humans ; Platelet Factor 4 ; pharmacology

OBJECTIVETo study the effect of oral administration of dimethyl dimethoxy biphenyl dicarboxylate (DDB) on adjusting angiogeneic/inflammatory mediators and ameliorating the pathology of bones in rats with collagen-induced arthritis (CIA).

METHODSWistar rat model of CIA was set up using bovine collagen type II. Fifty rats were divided into five groups randomly: normal, CIA model, DDB treatment, methotrexate (MTX) treatment, and combined DDB+MTX treatment. Ankle joints of rats were imaged with digital X-ray machine to show the destruction of joints. Fore and hind paw and knee joints were removed above the ankle joint then processed for haematoxylin and eosin staining. Plasma levels of vascular endothelial growth factor (VEGF), platelet derived growth factor, interleukin-8 (IL-8), IL-4, tumor necrosis factor α (TNF-α), and cyclooxygenase-2 (COX-2) were quantified by enzyme-linked immunosorbent assay. Nitric oxide levels were detected by Griess reagent.

RESULTSCompared with the CIA model group, a remarkable reduction in various angiogenic (VEGF and IL-8) and inflammatory mediators (TNF-α, IL-4 and COX-2) after treatment with DDB either alone or combined with MTX P<0.05 or P<0.01). Histopathological and X-ray findings were confirmatory to the observed DDB anti-arthritic effect. The DDB-treated group showed amelioration in signs of arthritis which appeared essentially similar to normal.

CONCLUSIONOur data shed light on the therapeutic efficacy of DDB in experimental rheumatoid arthritis (RA) compared with a choice drug (MTX) and it may be offered as a second-line drug in the treatment of RA.

Animals ; Arthritis, Experimental ; chemically induced ; diagnostic imaging ; drug therapy ; pathology ; Arthritis, Rheumatoid ; diagnostic imaging ; drug therapy ; pathology ; Collagen ; Cyclooxygenase 2 ; blood ; Dioxoles ; therapeutic use ; Enzyme-Linked Immunosorbent Assay ; Female ; Interleukin-4 ; blood ; Interleukin-8 ; blood ; Methotrexate ; therapeutic use ; Nitric Oxide ; biosynthesis ; Platelet-Derived Growth Factor ; analysis ; Radiography ; Rats ; Rats, Wistar ; Tumor Necrosis Factor-alpha ; blood ; Vascular Endothelial Growth Factor A ; blood

AIMTo study the effect of PF4 and relative peptide PF4 17-70 on the chemoattract ability, the expression of adhesion molecules and CXCR4 on the flesh cord blood CD34+ cells.

METHODSCD34+ cells were separated from the cord blood using MACS immune magnetic beads, the chemoattract ability was assayed using the Transwell board, the expression of adhesion molecules and CXCR4 was measured by FACS.

RESULTS(1) PF4 and PF4 17-70 increased the migration of the CD34+ cells, the chemoattract percentage of PF4 was 157.43% +/- 50.06% (P < 0.05) and PF4 17-70 was 187.02% +/- 10.69% (P < 0.05). (2) The expression of CD49d and CXCR4 on the CD34+ cells increased after PF4 incubated, but the expressions of other adherent molecules including CD31, CD44, CD11a, CD62p, CD62E did not change.

CONCLUSIONPF4 has the chemoattract ability on the umbilical blood CD34+ cells by promoting the expression of integrin CD49d and CXCR4, PF4 may help the cord stem cells homing.

Antigens, CD34 ; metabolism ; Cell Adhesion Molecules ; metabolism ; Chemotaxis ; drug effects ; Fetal Blood ; cytology ; drug effects ; Hematopoietic Stem Cells ; cytology ; drug effects ; Humans ; Integrin alpha4 ; metabolism ; Platelet Factor 4 ; pharmacology ; Receptors, CXCR4 ; metabolism