Objective: To study the effects of platelet activation and endothelial cell injury on the patients with malignant tumor and their prognoses.Methods: Radioimmunity and ELISA methods were employed to detect the TXB2, GM...Objective: To study the effects of platelet activation and endothelial cell injury on the patients with malignant tumor and their prognoses.Methods: Radioimmunity and ELISA methods were employed to detect the TXB2, GMP-140, vWF, cGMP and FN in 78 cases of malignant tumor and 40 healthy control persons.Results: The levels of TXB2, MP-140 and cGMP were increased in intestinal cancer group, lung cancer group and hepatic cancer group, while FN decreased in intestinal cancer and lung cancer group. cGMP was positively related to TXB2, GMP-140, vWF in malignant tumor group. FN was decreased in the group complicated with infection and the group with metastasis, while the other indexes increased. GMP-140, vWF and cGMP was decreased after operation except for the increasing of FN.Conclusion: Activations of platelet and injury of endothelial cells developed in patients with malignant tumor, and both of them affected the metastasis and prognosis of malignant tumor. Key words platelet activation - epithelium injury - malignant tumor - metastasis This work was supported by grants from Guangdong Medical Science foundation (A2000633).展开更多
Hyperlipidemia is a risk factor for clinically significant thrombotic events in cardiovascular diseases.Platelet reactivity in hyperlipidemic conditions is enhanced when platelet scavenger receptor CD36 recognizes oxi...Hyperlipidemia is a risk factor for clinically significant thrombotic events in cardiovascular diseases.Platelet reactivity in hyperlipidemic conditions is enhanced when platelet scavenger receptor CD36 recognizes oxidized lipids in oxidized low-density lipoprotein(ox-LDL)particles,a process that induces atherothrombosis.Sulforaphane(SFN)is a dietary isothiocyanate enriched in cruciferous vegetables and exerts multiple biological activities.The current study sought to investigate the efficacy of SFN on platelet hyperreactivity under hyperlipidemic conditions in vitro and in vivo.Using a series of platelet functional assays in human platelets in vitro,we demonstrated that SFN attenuated ox-LDL-increased platelet aggregation and activation(surface CD62P expression).Mechanistically,studies using pharmacological inhibitors clarified that these inhibitory effects of SFN were mainly modulated by down-regulating CD36-mediated activation of Src kinases,leading to enhanced activation of cyclic adenosine monophosphate/protein kinase A(cAMP/PKA)signaling,and resultant inhibition of NADPH oxidase 2(NOX2)-dependent generation of reactive oxygen species(ROS).Moreover,12-week supplementation of SFN-enriched broccoli sprout extract(BSE,0.06%diet)in hyperlipidemic C57BL/6J mice also decreased platelet hyperreactivity.Studies using pharmacological inhibitors of CD36,protein kinase A(PKA)and NOX2 showed that the efficacy of BSE supplementation was mainly through modulating CD36-mediated the cAMP/PKA/NOX2 signaling.Thus,through modulating the cAMP/PKA/NOX2 pathway and attenuating CD36-mediated platelet hyperreactivity,SFN may play important protective roles in atherothrombosis under hyperlipidemic conditions.展开更多
Hypoxemia is a common pathological state characterized by low oxygen saturation in the blood.This condition compromises mucosal barrier integrity particularly in the gut and oral cavity.However,the mechanisms underlyi...Hypoxemia is a common pathological state characterized by low oxygen saturation in the blood.This condition compromises mucosal barrier integrity particularly in the gut and oral cavity.However,the mechanisms underlying this association remain unclear.This study used periodontitis as a model to investigate the role of platelet activation in oral mucosal immunopathology under hypoxic conditions.Hypoxia upregulated methyltransferase-like protein 4(METTL4)expression in platelets,resulting in N6-methyladenine modification of mitochondrial DNA(mtDNA).This modification impaired mitochondrial transcriptional factor A-dependent cytosolic mtDNA degradation,leading to cytosolic mtDNA accumulation.Excess cytosolic mt-DNA aberrantly activated the cGAS-STING pathway in platelets.This resulted in excessive platelet activation and neutrophil extracellular trap formation that ultimately exacerbated periodontitis.Targeting platelet METTL4 and its downstream pathways offers a potential strategy for managing oral mucosa immunopathology.Further research is needed to examine its broader implications for mucosal inflammation under hypoxic conditions.展开更多
OBJECTIVE:To investigate whether cancer stem cells(CSCs) more efficiently activating platelets and evading immune surveillance than non-CSCs thus promoting metastasis.METHODS:We enriched and identified sphereforming c...OBJECTIVE:To investigate whether cancer stem cells(CSCs) more efficiently activating platelets and evading immune surveillance than non-CSCs thus promoting metastasis.METHODS:We enriched and identified sphereforming cells(SFCs) and coincubated washed platelets with several platelet activators including collagen,4T1 and SFCs.Platelet-coating tumor cells,platelet activation and TGF-β1 release were analyzed.Then natural kell cells(NK) were incubated with supernatants of different activated platelet samples what we called sample release(SR).The degranulation assay and NKG2 D expression on NK cells were conducted by flow cytometry.Finally tissue factor(TF) expression of SFCs or 4T1 were evaluated by western blot.RESULTS:Breast cancer cell line 4T1 could form spheres in serum-free medium at low adherence.Sphere-forming cells expressed high levels of the CD24-/lowCD44 + stem cell phenotype.Both sphere-forming cells or 4T1 were coated with abundant platelets while sphere-forming cells induced significantly higher expression of platelet activating receptor CD62 p than 4T1 did(P < 0.01).And sphere-forming cells induced platelets to produce more TGF-β1 than 4T1 did(P < 0.01).Furthermore,sample releases induced by sphere-forming cells caused more vigorous inhibition of NK cells antitumor reactivity(P < 0.05) and reduced NKG2 D expression(P < 0.01).The final results showed that sphere-forming cells expressed higher levels of TF than 4T1(P < 0.05).CONCLUSION:Our findings indicate that CSCs could efficiently activate platelets,induce platelets to secrete more TGF-β1,decrease NKG2 D expression and inhibit antitumor activity of NK cell,compared with 4T1.And higher levels of TF expression of CSCs may account for this correlation of CSCs and platelets.展开更多
AIM： To study the relationship between anti-β2- glycoprotein Ⅰ （aβ2GPⅠ） antibodies and platelet activation state in patients with ulcerative colitis （UC） and its significance. METHODS： Peripheral blood sampl...AIM： To study the relationship between anti-β2- glycoprotein Ⅰ （aβ2GPⅠ） antibodies and platelet activation state in patients with ulcerative colitis （UC） and its significance. METHODS： Peripheral blood samples were collected from 56 UC patients （34 males and 22 females, aged 43.5 years, range 21-66 years）, including 36 at active stage and 20 at remission stage, and 25 sex-and age-matched controls. The level of aβ2GP Ⅰ was measured by ELISA. The platelet activation markers, platelet activation complex- Ⅰ （PAC- Ⅰ ） and P-selectin （CD62P） were detected by flow cytometry. RESULTS： The A value for IgG aβ2GP Ⅰ in the active UC group was 0.61 ± 0.13, significantly higher than that in the remittent UC and control groups （0.50 ± 0.13 and 0.22 ± 0.14, P 〈 0.01）. There was a significant difference between the two groups （P 〈 0.01）. The A value for IgM aβ2GP Ⅰ in the active and remittent UC groups was 0.43 ± 0.13 and 0.38 ± 0.12, significantly higher than that in the control group （0.20 ± 0.12, P 〈 0.01）. However, there was no significant difference between the two groups （P 〉 0.05）. The PAC- Ⅰ positive rate for the active and remittent UC groups was 30.6% ± 7.6% and 19.6% ± 7.8% respectively, significantly higher than that for the control group （6.3% ± 1.7%,P 〈 0.01）. There was a significant difference between the two groups （P 〈 0.01）. The CD62P positive rate for the active and remittent UC groups was 45.0% ± 8.8% and 31.9% ± 7.8% respectively, significantly higher than that for the control group （9.2% ± 2.7%, P 〈 0.01）. There was a significant difference between the two groups （P 〈 0.01）. In the active UC group, the more severe the state of illness was, the higher the A value for IgG aβ2GP Ⅰ was, and the positive rate for PAC-Ⅰ and CD62P was positively correlated with the state of illness （Faβ2GP Ⅰ = 3.679, P 〈 0.05; FPAC-Ⅰ （%） = 5.346, P 〈 0.01; and FCD62P （%） = 5. 418, P 〈 0.01）. Meanwhile, in the same state of illness, the A value for IgG aβ2GP Ⅰ was positively correlated to the positive rates for PAC-Ⅰ and CD62P. CONCLUSION： aβ2GP Ⅰ level, platelet activation state and their relationship of them are closely correlated with the pathogenesis and development of UC.展开更多
Arsenic in drinking water is a worldwide health problem that is associated with cardiovascular disease, but the cause is currently unknown. In order to examine whether arsenic affects vasomotor tone in blood vessels, ...Arsenic in drinking water is a worldwide health problem that is associated with cardiovascular disease, but the cause is currently unknown. In order to examine whether arsenic affects vasomotor tone in blood vessels, we investigated the effect of arsenic on agonist-induced vasorelaxation and vasoconstriction using the isolated rat aortic rings in in vitro organ bath system. Treatment with inorganic arsenite (AsⅢ) inhibited acetylcholine-induced relaxation of aortic rings by inhibiting production of nitric oxide in endothelium.展开更多
In 1995,Huang et al.reported that rhodocytin,asnake toxin purified from callosdasma rhodostoma venomstimulates platelet aggregation.Ten years later,Suzuki-Inoue et al.identified C-type lectin-like receptor 2(CLEC-2)on...In 1995,Huang et al.reported that rhodocytin,asnake toxin purified from callosdasma rhodostoma venomstimulates platelet aggregation.Ten years later,Suzuki-Inoue et al.identified C-type lectin-like receptor 2(CLEC-2)on platelets as the rhodocytin receptor.Thereafter,several studies have showed that platelet CLEC-2 isinvolved in lymphatic/blood vessel separation,tumormetastasis and thrombus formation.展开更多
Platelet hyperreactivity contributes significantly to thrombosis in acute myocardial infarction and stroke. While antiplatelet drugs are used, residual ischemic risk remains. Intermittent fasting(IF), a dietary patter...Platelet hyperreactivity contributes significantly to thrombosis in acute myocardial infarction and stroke. While antiplatelet drugs are used, residual ischemic risk remains. Intermittent fasting(IF), a dietary pattern characterized by alternating periods of eating and fasting, has shown cardiovascular benefits, but its effect on platelet activation is unclear. This study demonstrates that IF inhibits platelet activation and thrombosis in both patients with coronary artery disease and apolipoprotein E(Apo E) knockout(Apo E-/-) mice, by enhancing intestinal flora production of indole-3-propionic acid(IPA). Mechanistically, elevated IPA in plasma directly attenuates platelet activation by binding to the platelet pregnane X receptor(PXR) and suppressing downstream signaling pathways, including Src/Lyn/Syk and LAT/PLCγ/PKC/Ca2+. Importantly, IF alleviates myocardial and cerebral ischemia/reperfusion injury in Apo E-/-mice. These findings suggest that IF mitigates platelet activation and thrombosis risk in coronary atherosclerosis by enhancing intestinal flora production of IPA, which subsequently activates the platelet PXR-related signaling pathways.展开更多
Platelet activation contributes to sepsis development,leading to microthrombosis and increased inflammation,which results in disseminated intravascular coagulation and multiple organ dysfunction.Although Cathelicidin ...Platelet activation contributes to sepsis development,leading to microthrombosis and increased inflammation,which results in disseminated intravascular coagulation and multiple organ dysfunction.Although Cathelicidin can alleviate sepsis,its role in sepsis regulation remains largely unexplored.In this study,we identified Cath-HG,a novel Cathelicidin from Hylarana guentheri skin,and analyzed its structure using nuclear magnetic resonance spectroscopy.The modulatory effect of Cath-HG on the symptoms of mice with sepsis induced by cecal ligation and puncture was evaluated in vivo,and the platelet count,degree of organ damage,and microthrombosis were measured.The antiplatelet aggregation activity of Cath-HG was studied in vitro,and its target was verified.Finally,we further investigated whether Cath-HG could regulate thrombosis in vivo in a FeCl3 injury-induced carotid artery model.The results showed that Cath-HG exhibited anα-helical structure in sodium dodecyl sulfate solution and effectively reduced organ inflammation and damage,improving survival in septic mice.It alleviated sepsis-induced thrombocytopenia and microthrombosis.In vitro,Cath-HG specifically inhibited collagen-induced platelet aggregation and modulated glycoprotein VI(GPVI)signaling pathways.Dot blotting,enzyme-linked immunosorbent assay,and pull-down experiments confirmed GPVI as the target of Cath-HG.Molecular docking and amino acid residue truncations/mutations identified crucial sites of Cath-HG.These findings suggest that GPVI represents a promising therapeutic target for sepsis,and Cath-HG may serve as a potential treatment for sepsis-related thrombocytopenia and thrombotic events.Additionally,identifying Cath-HG as a GPVI inhibitor provides insights for developing novel antithrombotic therapies targeting platelet activation mediated by GPVI.展开更多
A synthetic diblock copolymer poly（2-ethyl-2-oxazoline）-poly（D,L-lactide） （PEOz-PLA） can self-assemble into micelles with an increased efficiency of drug delivery. However, the interactions of blood-micelles and...A synthetic diblock copolymer poly（2-ethyl-2-oxazoline）-poly（D,L-lactide） （PEOz-PLA） can self-assemble into micelles with an increased efficiency of drug delivery. However, the interactions of blood-micelles and cell-micelles remain unclear. In the present study, we aimed to assess the hemocompatibility and cytocompatibility of PEOz-PLA micelles in order to clarify its potentials as carriers for drug delivery. Blood compatibility of the micelles was evaluated by hemolysis analysis, coagulation test, platelet activation investigation and assessment of their interaction with protein. The results revealed that PEOz-PLA micelles had a favorable blood compatibility. In addition, PEOz-PLA micelles showed a good cytocompatibility through SRB assay, presenting only negligible cytotoxicity when incubated with KBv cells. Taken together, PEOz-PLA micelles could be used as a hemocompatible and cytocompatible drug carrier for intravenous administration.展开更多
The effects of berbamine, an alkaloid of dibenzylisoquinoline, on PAF produc tion in human neutrophils and on platelet aggregation induced by PAF were studied and compared with those of the calcium antagonist verapam...The effects of berbamine, an alkaloid of dibenzylisoquinoline, on PAF produc tion in human neutrophils and on platelet aggregation induced by PAF were studied and compared with those of the calcium antagonist verapamil. Preincubation with berbamine (50 mmol / L, 100 mmol / L) or verapamil (10 mmol / L, 100 mmol / L) was shown to significantly inhibit A 23187 stimulated PAF synthesis. Berbamine and verapamil were found to inhibit platelet aggregation induced by PAF 70 pmol / L in a dose dependent manner. These results suggest that the inhibitory effects of berbamine and verapamil on A 23187 stimulated PAF synthesis in human neutrophils and PAF induced platelet aggregation are possibly brought about by inhibiting cellular calcium influx.展开更多
AIM:To investigate the dynamic changes and significance of platelet activating factor receptor (PAF-R) mRNA and protein in pancreatic tissues of rats with severe acute pancreatitis (SAP) and effects of BN52021 (Ginkgo...AIM:To investigate the dynamic changes and significance of platelet activating factor receptor (PAF-R) mRNA and protein in pancreatic tissues of rats with severe acute pancreatitis (SAP) and effects of BN52021 (Ginkgolide B). METHODS:Wistar male rats were randomly assigned to the negative control group (NC group),SAP model group (SAP group),and BN52051-remedy group (BN group),and each of the groups was divided into 6 subgroups at different time points after operation (1 h,2 h,3 h,6 h,12 h,and 24 h) (n=10 in each). PT-PCR and Western blot methods were used to detect PAF-RmRNA and protein expression in pancreatic tissues of rats respectively. Pathological examination of pancreatic tissues was performed and the serum amylase change was detected. RESULTS:Serum amylase and pathological results showed the that SAP model was successfully prepared,BN52021 was able to decrease serum amylase,and the pathological ratings in BN group at 3 h,6 h,and 12 h significantly decreased compared with those in the SAP group (8.85 ± 0.39 vs 5.95 ± 0.19,9.15 ± 0.55 vs 5.55 ± 0.36,10.10 ± 0.65 vs 6.72 ± 0.30,P < 0.05). The result of PAF-mRNA showed dynamic changes in SAP and BN groups,which increased gradually in early stage,reached a peak at 3 h (0.71 ± 0.14 vs 0.54 ± 0.14,0.69 ± 0.13 vs 0.59 ± 0.04,P < 0.05),and decreased gradually later. There were significant differences at each time point except 1 h and 2 h,when compared with those in the NC group (0.71 ± 0.14 or 0.69 ± 0.13 vs 0.47 ± 0.10,0.38 ± 0.08 or 0.59 ± 0.04 vs 0.47 ± 0.09,0.25 ± 0.07 or 0.29 ± 0.05 vs 0.46 ± 0.10,0.20 ± 0.06 or 0.20± 0.04 vs 0.43 ± 0.09,P < 0.05),whereas there was no significant difference between BN and SAP groups at each time point. The result of PAF-R protein showed that the change of PAF-R protein in the SAP group and the BN group was consistent with that of PAF-R mRNA. There were significant differences at each time point except 1 h,when compared with those in the NC group (0.90 ± 0.02 or 0.80 ± 0.05 vs 0.48 ± 0.02,1.69 ± 0.06 or 1.58 ± 0.02 vs 0.48 ± 0.03,1.12 ± 0.10 or 0.98 ± 0.03 vs 0.49 ± 0.09,1.04 ± 0.14 or 0.87 ± 0.02 vs 0.52 ± 0.08,0.97 ± 0.16 or 0.90 ± 0.05 vs 0.49 ± 0.10,P < 0.05),whereas there was no significant difference between the BN group and the SAP group. CONCLUSION:PAF-R plays an important role in occurrence and development of SAP. BN52021 exerts biological effects through competitively inhibiting the binding of increased both PAF and PAF-R expression rather than through decreasing PAF-R expression in pancreatic tissues.展开更多
AIM:To determine the optimal dosage and mechanism of Ginkgolide B(BN52021) on severe acute pancreatitis(SAP) of rats.METHODS:Seventy male Wistar rats were randomly divided into seven groups(10 for each group).Shamoper...AIM:To determine the optimal dosage and mechanism of Ginkgolide B(BN52021) on severe acute pancreatitis(SAP) of rats.METHODS:Seventy male Wistar rats were randomly divided into seven groups(10 for each group).Shamoperation group(SO),SAP model group(SAP),dimethyl sulfoxide(DMSO) contrast group(DMSO),and groups treated with 2.5 mg/kg BN52021(BN1),5 mg/kg BN52021(BN2),10 mg/kg BN52021(BN3),and 20 μg/kg Sandostatin(SS).The SAP model was established in Wistar rats by injecting 5% sodium taurocholate retrogradely into the common bilio-pancreatic duct.The rats of SO,DMSO and BN52021 were injected with 0.9% NaCl,0.5% DMSO and BN52021 through femoral vein 15 min after the operation.The SS group was injected with Sandostatin subcutaneously.All rats were anaesthetized at 6 h after operation,and venous blood was collected to determine the levels of serum amylase and phospholipase A2(PLA2),and pancreas tissue was harvested and stained.RESULTS:There was no significant difference between the SAP and DMSO groups in serum amylase level,PLA2,ascites and pathologic score,but significant difference was found in SAP/DMSO groups compared with those in SO group(P < 0.05) and the levels of serum amylase,PLA2,ascites,and pathologic score were lower in the BN1,BN2,BN3 and SS groups than in the SAP and DMSO groups(P < 0.05).However,among BN1,BN2,BN3 and SS groups,BN2 had the best effect in decreasing the levels of serum amylase and PLA2(P < 0.05).Expression of platelet activating factor(PAF) receptor(PAFR) mRNA and protein showed no significant difference between the SAP and DMSO groups,or among BN1,BN2,BN3 and SS groups,but there was remarkable difference between SAP/DMSO group and SO group(P < 0.05),and expression of PAFR mRNA and protein was higher in the BN1,BN2,BN3 and SS groups than in the SAP and DMSO groups(P < 0.05).PAFR expression was observed in the nucleus and cytoplasm of pancreatic islet cells in Wistar rats by immunohistochemistry.CONCLUSION:By iv injection,5 mg/kg of BN52021 is the optimal dosage for SAP rats.BN52021 may inhibit the interaction/binding of PAF with PAFR.展开更多
To explore the effect of Buyang Huanwu Decoction (BHD) on platelet activating factor (PAF) content in arterial blood pre- and post-arterial thrombosis in rats, male Wistar rats were randomly divided into 3 groups, the...To explore the effect of Buyang Huanwu Decoction (BHD) on platelet activating factor (PAF) content in arterial blood pre- and post-arterial thrombosis in rats, male Wistar rats were randomly divided into 3 groups, the medicine group treated with BHD, the control group with dexamethasone liquid, and the blank group with distilled water. Oral administration was given for 14 consecutive days, once daily. Model of arterial thrombosis was established in the animals 2 hours after final medication, the blood content of PAF, dry weight (DW) and occlusion time (OT) of thrombus, and dry weight of thrombus/body weight (TW/BW) ratio were observed. Results indicated that BHD could markedly lower the arterial blood content of PAF after thrombosis, increase the OT of thrombus, reduce the dry weight of thrombus and the TW/BW ratio (P展开更多
AIM： To evaluate the changes in hepatic platelet activating factor （PAF） and its receptors and their effect on portal pressure of cirrhotic rats induced by CCh. METHODS： A model of liver cirrhosis was replicated i...AIM： To evaluate the changes in hepatic platelet activating factor （PAF） and its receptors and their effect on portal pressure of cirrhotic rats induced by CCh. METHODS： A model of liver cirrhosis was replicated in rats by intra-peritoneal injection of CCh for 8 wk. We determined the effect of hepatic PAF and its receptor level on portal and arterial pressure by EIA, saturation binding and RT-PCR technique. RESULTS： Compared to control rats, cirrhotic rats had higher hepatic PAF levels and output as well as higher plasma PAF levels （P〈0.01, P〈0.01, P〈0.05, respectively）. Both hepatic PAF receptor mRNA levels and PAF binding were nearly 3-fold greater in cirrhotic rats （P〈0.01）. Portal injection of PAF （1 g/kg WT） increased the portal pressure by 22% and 33% in control and cirrhotic rats, respectively. In contrast, the arterial pressure was decreased in the both groups （54% in control rats and 42% in cirrhotic rats）. Injection of the PAF antagonist BN52021 （5 mg/kg WT） decreased the portal pressure by 16% in cirrhotic rats but had no effect in the control rats. CONCLUSION： The upregulation of the PAF system contributes to hepatic hemodynamic and metabolic abnormalities in drrhosis, and the increased release of PAF into the circulation has impacts on the systemic hemodynamics.展开更多
AIM:To determine the platelet-activating factor (PAF) synthesis and its receptor expression in Kupffer cells in rat carbon tetrachloride-induced cirrhosis. METHODS:Kupffer cells, isolated from the livers of control an...AIM:To determine the platelet-activating factor (PAF) synthesis and its receptor expression in Kupffer cells in rat carbon tetrachloride-induced cirrhosis. METHODS:Kupffer cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium overnight. PAF saturation binding, ET-1 saturation and competition binding were assayed. ET-1 induced PAF synthesis, mRNA expression of PAF, preproendothelin-1, endothelin A (ETA) and endothelin B (ETB) receptors were also determined. RESULTS:A two-fold increase of PAF synthesis (1.42 ± 0.14 vs 0.66 ± 0.04 pg/μg DNA) and a 1.48-fold increase of membrane-bound PAF (1.02 ± 0.06 vs 0.69 ± 0.07 pg/μg DNA) were observed in activated Kupffer cells of cirrhotic rats. The application of ET-1 to Kupffer cells induced PAF synthesis in a concentration-dependent manner in both cirrhotic and normal rats via ETB receptor, but PAF synthesis in the activated Kupffer cells was more effective than that in the normal Kupffer cells. In activated Kupffer cells, PAF receptor expression and PAF binding capacity were markedly enhanced. Activated Kupffer cells raised the [125I]-ET-1 binding capacity, but changed neither the affinity of the receptors, nor the expression of ETA receptor. CONCLUSION:Kupffer cells in the course of CCl4-induced cirrhosis are the main source of increased PAF. ET-1 is involved endogenously in stimulating the PAF synthesis in activated Kupffer cells via ETB receptor by paracrine. ETA receptor did not appear in activated Kupffer cells, which may exacerbate the hepatic and extrahepatic complications of cirrhosis.展开更多
Objective The mechanism through which platelet activating factor （PAF） induces cardiac electrical activity and arrhythmia is not well understood and previous studies have suggested a potential involvement of ion cha...Objective The mechanism through which platelet activating factor （PAF） induces cardiac electrical activity and arrhythmia is not well understood and previous studies have suggested a potential involvement of ion channels in its action. The present study was aimed to clarify the role of PAF in fatal arrhythmias following acute myocardia infarction （AMI） and the underlying mechanism. Methods （1） Blood PAF levels were measured among 72 AMI patients at the time of diagnosis with AMI and 48 h later, and their electrocardiogram （ECG） was recorded continuously. （2） Ischemia simulation and surface electrocardiogram were conducted in 20 pigs and their PAF levels were measured. （3） PAF perfusion and standard microelectrode recording were performed on guinea pig papillarymuscles. Results In both humans and pigs, elevated PAF levels were detected in AMI and simulated ischemia, respectively, and even higher PAF levels were found when fatal arrhythmias occurred. In guinea pig myocardium, PAF induced a shortening of action potential duration at 90% level of repolarization （APD 90 ）under non-ischemic conditions and a more pronounced shortening under early simulated ischemic conditions. Conclusion AMI and ischemia are associated with increased PAF levels in humans and pigs, which are further raised when fatal arrhythmia follows. The effects of PAF on the myocardium may be mediated by multiple ion channels.展开更多
AIM: To determine platelet activating factor (PAF) receptor expression in cirrhotic hepatic stellate cells.METHODS: Hepatic stellate cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were pla...AIM: To determine platelet activating factor (PAF) receptor expression in cirrhotic hepatic stellate cells.METHODS: Hepatic stellate cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium after overnight culture. We determined the PAF receptor in hepatic stellate cells by saturation binding technique and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), and the effects of PAF and its antagonist BN52021 on prostaglandin E2 (PGE2) release by stellate cells.RESULTS: Scatchard analysis indicated the presence of PAF receptor with dissociation constant (Kd) of 4.66 nmol/L and maximum binding capacity (Bmax) of 24.65 fmol/μg in cirrhotic stellate cells. Compared with the control, the maximum PAF binding capacity increased significantly (Bmax: 24.65 ± 1.96 fmol/μg. DNA, R = 0.982 vs 5.74 ± 1.55 fmol/μg. DNA, R = 0.93; P < 0.01), whereas receptor affinity had no significant difference (Kd of 4.66 ± 0.33 nmol/L for the cirrhosis and 3.51 ± 0.26 nmol/L for the control; P > 0.05). Consistent with the receptor binding data, the mRNA expression of PAF receptor was increased significantly in cirrhotic stellate cells. PAF in a concentration-dependent manner induced PGE2 synthesis in cirrhotic hepatic stellate cells, but the effects were blocked significantly by BN52021.CONCLUSION: Cirrhosis sensitizes hepatic stellate cells to PAF by elevating its receptor level and hepatic stellate cells maybe potential effectors of PAF induced portal hypertension.展开更多
AIM To evaluate platelet activation markers in psoriasis patients, compared to controls, and investigate their association with the inflammatory burden of psoriasis.METHODS Forty psoriatic patients without cardiovascu...AIM To evaluate platelet activation markers in psoriasis patients, compared to controls, and investigate their association with the inflammatory burden of psoriasis.METHODS Forty psoriatic patients without cardiovascular disease,and 12 healthy controls were subjected to measurement of baseline platelet CD62 P, CD63 and CD42 b expression, platelet-leukocyte complexes, i.e., platelet-monocyte complexes(PMC), platelet-neutrophil complexes(PNC) and platelet-lymphocyte complexes, and concentrations of platelet-derived microparticles(PMPs) using flow cytometry. Both larger-size(0.5-0.9 μm) and smallersize(< 0.5 μm) PMPs were determined. Serum interleukin(IL)-12 and IL-17 levels were also measured by enzyme-linked immunosorbent assay. The severity of psoriasis was evaluated by the Psoriasis Area Severity Index(PASI).RESULTS PMP concentrations were significantly higher in psoriasis patients than controls [mean±standard error of mean(SEM): 22±5/μL vs 11±6/μL; P=0.018), for both smaller-size(10±2/μL vs 4±2/μL; P=0.033) and larger-size(12±3/μL vs 6±4/μL; P=0.014) PMPs. Platelet CD62 P, CD63 and CD42 b expression and circulating PMC and PNC were similar between the two groups. Lower circulating PLC were observed in psoriasis patients compared to controls(mean±SEM: 16%±3% vs 23%±6%; P=0.047). Larger-size PMPs were related with IL-12 levels(P<0.001) and smaller-size PMPs with both IL-12 and IL-17 levels(P<0.001). Total PMPs also correlated with IL-12(P<0.001). CD63 expression was positively correlated with both IL-12 and IL-17(P<0.05). Increased PASI score was associated with increased levels of larger-size PMPs(r=0.45; P=0.011) and increased CD63 expression(r=0.47; P<0.01).CONCLUSION PMPs, known to be predictive of cardiovascular outcomes, are increased in psoriasis patients, and associated with high inflammatory disease burden. Enhanced platelet activation may be the missing link leading to cardiovascular events in psoriatic patients.展开更多
Objective.To establish a flow cytometric internal standard method for counting platelet-derived microparti-cles(PMPs)and to study its clinical significance. Methods. PMPs suspension(platelet poor plasma,PPP) was extra...Objective.To establish a flow cytometric internal standard method for counting platelet-derived microparti-cles(PMPs)and to study its clinical significance. Methods. PMPs suspension(platelet poor plasma,PPP) was extracted by gradual centrifugation. According to the size of PMPs,3 μm and 0.8μm latex beads were used as internal standards for the quantitation. PMPs were counted by adjusting flow cytometric discrimination and voltage of forward scatter and side scatter. Results. In 30 healthy donors,the average concentration of resting PMPs was(1.2×105±5.7×104 )/ml and that of activated PMPs was(1.6×106±9.1×105)/ml. Compared with healthy donors,PMPs mean value was significantly higher(P< 0.001)in 18 patients with coronary artery disease,12 with acute cerebral infraction and 23 with chronic renal failure[the average PMPs concentration,( 6.1×105±2.5×105 )/ml, ( 6.8×105±3.4×105)/ml and(5.9×105±3.1×105)/ml respectively]. However,no significant difference in PMPs concentration was observed in 25 patients with acute leukemia and severe thrombocytopenia during the aplastic phase after chemotherapy [1.3×105±6.1×104)/ml,(P >0.05)] .Conclusions. PMPs is a useful indicator in monitoring platelet activation,and plays an important role in thrombotic disease. By flow cytometric internal standard method,PMPs can be counted rapidly and accurately,which may be very helpful in interlaboratory comparative studies.展开更多
基金This work was supported by grants from Guangdong Medical Science foundation(A2000633).
文摘Objective: To study the effects of platelet activation and endothelial cell injury on the patients with malignant tumor and their prognoses.Methods: Radioimmunity and ELISA methods were employed to detect the TXB2, GMP-140, vWF, cGMP and FN in 78 cases of malignant tumor and 40 healthy control persons.Results: The levels of TXB2, MP-140 and cGMP were increased in intestinal cancer group, lung cancer group and hepatic cancer group, while FN decreased in intestinal cancer and lung cancer group. cGMP was positively related to TXB2, GMP-140, vWF in malignant tumor group. FN was decreased in the group complicated with infection and the group with metastasis, while the other indexes increased. GMP-140, vWF and cGMP was decreased after operation except for the increasing of FN.Conclusion: Activations of platelet and injury of endothelial cells developed in patients with malignant tumor, and both of them affected the metastasis and prognosis of malignant tumor. Key words platelet activation - epithelium injury - malignant tumor - metastasis This work was supported by grants from Guangdong Medical Science foundation (A2000633).
基金supported by the National Natural Science Foundation of China(82003451 and 82003455)Yunnan Fundamental Research Projects(202101AT070033)the Start-Up Fund for Introduction of High-level Talents to Dali University(YBS2021015).
文摘Hyperlipidemia is a risk factor for clinically significant thrombotic events in cardiovascular diseases.Platelet reactivity in hyperlipidemic conditions is enhanced when platelet scavenger receptor CD36 recognizes oxidized lipids in oxidized low-density lipoprotein(ox-LDL)particles,a process that induces atherothrombosis.Sulforaphane(SFN)is a dietary isothiocyanate enriched in cruciferous vegetables and exerts multiple biological activities.The current study sought to investigate the efficacy of SFN on platelet hyperreactivity under hyperlipidemic conditions in vitro and in vivo.Using a series of platelet functional assays in human platelets in vitro,we demonstrated that SFN attenuated ox-LDL-increased platelet aggregation and activation(surface CD62P expression).Mechanistically,studies using pharmacological inhibitors clarified that these inhibitory effects of SFN were mainly modulated by down-regulating CD36-mediated activation of Src kinases,leading to enhanced activation of cyclic adenosine monophosphate/protein kinase A(cAMP/PKA)signaling,and resultant inhibition of NADPH oxidase 2(NOX2)-dependent generation of reactive oxygen species(ROS).Moreover,12-week supplementation of SFN-enriched broccoli sprout extract(BSE,0.06%diet)in hyperlipidemic C57BL/6J mice also decreased platelet hyperreactivity.Studies using pharmacological inhibitors of CD36,protein kinase A(PKA)and NOX2 showed that the efficacy of BSE supplementation was mainly through modulating CD36-mediated the cAMP/PKA/NOX2 signaling.Thus,through modulating the cAMP/PKA/NOX2 pathway and attenuating CD36-mediated platelet hyperreactivity,SFN may play important protective roles in atherothrombosis under hyperlipidemic conditions.
基金supported by the National Natural Science Foundation of China(82325012)the Youth Fund of the National Natural Science Foundation of China(82301043)+1 种基金the Natural Science Basic Research Program of Shaanxi (Program No.2024JC-YBQN-0980)the Shaanxi Key Scientific and Technological Innovation Team(2020TD-033).
文摘Hypoxemia is a common pathological state characterized by low oxygen saturation in the blood.This condition compromises mucosal barrier integrity particularly in the gut and oral cavity.However,the mechanisms underlying this association remain unclear.This study used periodontitis as a model to investigate the role of platelet activation in oral mucosal immunopathology under hypoxic conditions.Hypoxia upregulated methyltransferase-like protein 4(METTL4)expression in platelets,resulting in N6-methyladenine modification of mitochondrial DNA(mtDNA).This modification impaired mitochondrial transcriptional factor A-dependent cytosolic mtDNA degradation,leading to cytosolic mtDNA accumulation.Excess cytosolic mt-DNA aberrantly activated the cGAS-STING pathway in platelets.This resulted in excessive platelet activation and neutrophil extracellular trap formation that ultimately exacerbated periodontitis.Targeting platelet METTL4 and its downstream pathways offers a potential strategy for managing oral mucosa immunopathology.Further research is needed to examine its broader implications for mucosal inflammation under hypoxic conditions.
基金Supported by the National Natural Science Foundation of China(the Research of Traditional Chinese Medicien Regulating the Tumor Metastasis due to Cancer Stem Cell Related Expression of TF and TF/FⅦSignal Pathway Based on Traditional Chinese Mediceory of"Fu Du",No.81273947)the International S&T Cooperation Program Office of China(Herbal Medicine with Different Treatment Principles on Regulating the Biological Behaviour of Cancer Stem Cells and its Regulatory Factors,No.2013DFA32540)
文摘OBJECTIVE:To investigate whether cancer stem cells(CSCs) more efficiently activating platelets and evading immune surveillance than non-CSCs thus promoting metastasis.METHODS:We enriched and identified sphereforming cells(SFCs) and coincubated washed platelets with several platelet activators including collagen,4T1 and SFCs.Platelet-coating tumor cells,platelet activation and TGF-β1 release were analyzed.Then natural kell cells(NK) were incubated with supernatants of different activated platelet samples what we called sample release(SR).The degranulation assay and NKG2 D expression on NK cells were conducted by flow cytometry.Finally tissue factor(TF) expression of SFCs or 4T1 were evaluated by western blot.RESULTS:Breast cancer cell line 4T1 could form spheres in serum-free medium at low adherence.Sphere-forming cells expressed high levels of the CD24-/lowCD44 + stem cell phenotype.Both sphere-forming cells or 4T1 were coated with abundant platelets while sphere-forming cells induced significantly higher expression of platelet activating receptor CD62 p than 4T1 did(P < 0.01).And sphere-forming cells induced platelets to produce more TGF-β1 than 4T1 did(P < 0.01).Furthermore,sample releases induced by sphere-forming cells caused more vigorous inhibition of NK cells antitumor reactivity(P < 0.05) and reduced NKG2 D expression(P < 0.01).The final results showed that sphere-forming cells expressed higher levels of TF than 4T1(P < 0.05).CONCLUSION:Our findings indicate that CSCs could efficiently activate platelets,induce platelets to secrete more TGF-β1,decrease NKG2 D expression and inhibit antitumor activity of NK cell,compared with 4T1.And higher levels of TF expression of CSCs may account for this correlation of CSCs and platelets.
基金The National Natural Science Foundation of China, No. 30572106
文摘AIM： To study the relationship between anti-β2- glycoprotein Ⅰ （aβ2GPⅠ） antibodies and platelet activation state in patients with ulcerative colitis （UC） and its significance. METHODS： Peripheral blood samples were collected from 56 UC patients （34 males and 22 females, aged 43.5 years, range 21-66 years）, including 36 at active stage and 20 at remission stage, and 25 sex-and age-matched controls. The level of aβ2GP Ⅰ was measured by ELISA. The platelet activation markers, platelet activation complex- Ⅰ （PAC- Ⅰ ） and P-selectin （CD62P） were detected by flow cytometry. RESULTS： The A value for IgG aβ2GP Ⅰ in the active UC group was 0.61 ± 0.13, significantly higher than that in the remittent UC and control groups （0.50 ± 0.13 and 0.22 ± 0.14, P 〈 0.01）. There was a significant difference between the two groups （P 〈 0.01）. The A value for IgM aβ2GP Ⅰ in the active and remittent UC groups was 0.43 ± 0.13 and 0.38 ± 0.12, significantly higher than that in the control group （0.20 ± 0.12, P 〈 0.01）. However, there was no significant difference between the two groups （P 〉 0.05）. The PAC- Ⅰ positive rate for the active and remittent UC groups was 30.6% ± 7.6% and 19.6% ± 7.8% respectively, significantly higher than that for the control group （6.3% ± 1.7%,P 〈 0.01）. There was a significant difference between the two groups （P 〈 0.01）. The CD62P positive rate for the active and remittent UC groups was 45.0% ± 8.8% and 31.9% ± 7.8% respectively, significantly higher than that for the control group （9.2% ± 2.7%, P 〈 0.01）. There was a significant difference between the two groups （P 〈 0.01）. In the active UC group, the more severe the state of illness was, the higher the A value for IgG aβ2GP Ⅰ was, and the positive rate for PAC-Ⅰ and CD62P was positively correlated with the state of illness （Faβ2GP Ⅰ = 3.679, P 〈 0.05; FPAC-Ⅰ （%） = 5.346, P 〈 0.01; and FCD62P （%） = 5. 418, P 〈 0.01）. Meanwhile, in the same state of illness, the A value for IgG aβ2GP Ⅰ was positively correlated to the positive rates for PAC-Ⅰ and CD62P. CONCLUSION： aβ2GP Ⅰ level, platelet activation state and their relationship of them are closely correlated with the pathogenesis and development of UC.
文摘Arsenic in drinking water is a worldwide health problem that is associated with cardiovascular disease, but the cause is currently unknown. In order to examine whether arsenic affects vasomotor tone in blood vessels, we investigated the effect of arsenic on agonist-induced vasorelaxation and vasoconstriction using the isolated rat aortic rings in in vitro organ bath system. Treatment with inorganic arsenite (AsⅢ) inhibited acetylcholine-induced relaxation of aortic rings by inhibiting production of nitric oxide in endothelium.
文摘In 1995,Huang et al.reported that rhodocytin,asnake toxin purified from callosdasma rhodostoma venomstimulates platelet aggregation.Ten years later,Suzuki-Inoue et al.identified C-type lectin-like receptor 2(CLEC-2)on platelets as the rhodocytin receptor.Thereafter,several studies have showed that platelet CLEC-2 isinvolved in lymphatic/blood vessel separation,tumormetastasis and thrombus formation.
基金supported by the grants to J.G. from the National Basic Research Center of China (T2288101)the Shanghai Clinical Research Center for Interventional Medicine (19MC1910300)+7 种基金the Shanghai Municipal Key Clinical Specialty (shslczdzk01701)the State Key Clinical Specialty Construction Project (YW2021-002)the National Natural Science Foundation of China (81970298)the Clinical Research Special Fund of Zhongshan Hospital Fudan University (2020ZSLC57)2021 Clinical Research Navigation Project of Shanghai Medical College of Fudan Universitythe National Natural Science Foundation of China (82100355)the Shanghai Sailing Program (21YF1406000)the Shanghai Science and Technology Innovation Fund (22S31904900)
文摘Platelet hyperreactivity contributes significantly to thrombosis in acute myocardial infarction and stroke. While antiplatelet drugs are used, residual ischemic risk remains. Intermittent fasting(IF), a dietary pattern characterized by alternating periods of eating and fasting, has shown cardiovascular benefits, but its effect on platelet activation is unclear. This study demonstrates that IF inhibits platelet activation and thrombosis in both patients with coronary artery disease and apolipoprotein E(Apo E) knockout(Apo E-/-) mice, by enhancing intestinal flora production of indole-3-propionic acid(IPA). Mechanistically, elevated IPA in plasma directly attenuates platelet activation by binding to the platelet pregnane X receptor(PXR) and suppressing downstream signaling pathways, including Src/Lyn/Syk and LAT/PLCγ/PKC/Ca2+. Importantly, IF alleviates myocardial and cerebral ischemia/reperfusion injury in Apo E-/-mice. These findings suggest that IF mitigates platelet activation and thrombosis risk in coronary atherosclerosis by enhancing intestinal flora production of IPA, which subsequently activates the platelet PXR-related signaling pathways.
基金supported by the Key-Area Research and Development Program of Guangdong Province(2023B1111050008)the GuangDong Basic and Applied Basic Research Foundation(2023A1515010914)and the Key-Area Research and Development Program of Guangzhou(2024B03J0011)+1 种基金Our work received support also by the Czech Academy of Sciences within project No.NSFC-19-15(bilateral cooperation)“Belt and Road”Innovative Talent Exchange Foreign Expert Program(DL2023030011L).
文摘Platelet activation contributes to sepsis development,leading to microthrombosis and increased inflammation,which results in disseminated intravascular coagulation and multiple organ dysfunction.Although Cathelicidin can alleviate sepsis,its role in sepsis regulation remains largely unexplored.In this study,we identified Cath-HG,a novel Cathelicidin from Hylarana guentheri skin,and analyzed its structure using nuclear magnetic resonance spectroscopy.The modulatory effect of Cath-HG on the symptoms of mice with sepsis induced by cecal ligation and puncture was evaluated in vivo,and the platelet count,degree of organ damage,and microthrombosis were measured.The antiplatelet aggregation activity of Cath-HG was studied in vitro,and its target was verified.Finally,we further investigated whether Cath-HG could regulate thrombosis in vivo in a FeCl3 injury-induced carotid artery model.The results showed that Cath-HG exhibited anα-helical structure in sodium dodecyl sulfate solution and effectively reduced organ inflammation and damage,improving survival in septic mice.It alleviated sepsis-induced thrombocytopenia and microthrombosis.In vitro,Cath-HG specifically inhibited collagen-induced platelet aggregation and modulated glycoprotein VI(GPVI)signaling pathways.Dot blotting,enzyme-linked immunosorbent assay,and pull-down experiments confirmed GPVI as the target of Cath-HG.Molecular docking and amino acid residue truncations/mutations identified crucial sites of Cath-HG.These findings suggest that GPVI represents a promising therapeutic target for sepsis,and Cath-HG may serve as a potential treatment for sepsis-related thrombocytopenia and thrombotic events.Additionally,identifying Cath-HG as a GPVI inhibitor provides insights for developing novel antithrombotic therapies targeting platelet activation mediated by GPVI.
基金National Natural Science Foundation of China(Grant No.81172990)the National Key Science Research Program of China(Grant No.973 Program,2009CB930300)+1 种基金Innovation Team of Ministry of Education(Grant No.BMU20110263)the Open Project Program of State Key Laboratory of Drug Delivery Technology and Pharmacokinetics,Tianjin Institute of Pharmaceutical Research
文摘A synthetic diblock copolymer poly（2-ethyl-2-oxazoline）-poly（D,L-lactide） （PEOz-PLA） can self-assemble into micelles with an increased efficiency of drug delivery. However, the interactions of blood-micelles and cell-micelles remain unclear. In the present study, we aimed to assess the hemocompatibility and cytocompatibility of PEOz-PLA micelles in order to clarify its potentials as carriers for drug delivery. Blood compatibility of the micelles was evaluated by hemolysis analysis, coagulation test, platelet activation investigation and assessment of their interaction with protein. The results revealed that PEOz-PLA micelles had a favorable blood compatibility. In addition, PEOz-PLA micelles showed a good cytocompatibility through SRB assay, presenting only negligible cytotoxicity when incubated with KBv cells. Taken together, PEOz-PLA micelles could be used as a hemocompatible and cytocompatible drug carrier for intravenous administration.
文摘The effects of berbamine, an alkaloid of dibenzylisoquinoline, on PAF produc tion in human neutrophils and on platelet aggregation induced by PAF were studied and compared with those of the calcium antagonist verapamil. Preincubation with berbamine (50 mmol / L, 100 mmol / L) or verapamil (10 mmol / L, 100 mmol / L) was shown to significantly inhibit A 23187 stimulated PAF synthesis. Berbamine and verapamil were found to inhibit platelet aggregation induced by PAF 70 pmol / L in a dose dependent manner. These results suggest that the inhibitory effects of berbamine and verapamil on A 23187 stimulated PAF synthesis in human neutrophils and PAF induced platelet aggregation are possibly brought about by inhibiting cellular calcium influx.
基金the National Natural Science Foundation of China, No. 30300465
文摘AIM:To investigate the dynamic changes and significance of platelet activating factor receptor (PAF-R) mRNA and protein in pancreatic tissues of rats with severe acute pancreatitis (SAP) and effects of BN52021 (Ginkgolide B). METHODS:Wistar male rats were randomly assigned to the negative control group (NC group),SAP model group (SAP group),and BN52051-remedy group (BN group),and each of the groups was divided into 6 subgroups at different time points after operation (1 h,2 h,3 h,6 h,12 h,and 24 h) (n=10 in each). PT-PCR and Western blot methods were used to detect PAF-RmRNA and protein expression in pancreatic tissues of rats respectively. Pathological examination of pancreatic tissues was performed and the serum amylase change was detected. RESULTS:Serum amylase and pathological results showed the that SAP model was successfully prepared,BN52021 was able to decrease serum amylase,and the pathological ratings in BN group at 3 h,6 h,and 12 h significantly decreased compared with those in the SAP group (8.85 ± 0.39 vs 5.95 ± 0.19,9.15 ± 0.55 vs 5.55 ± 0.36,10.10 ± 0.65 vs 6.72 ± 0.30,P < 0.05). The result of PAF-mRNA showed dynamic changes in SAP and BN groups,which increased gradually in early stage,reached a peak at 3 h (0.71 ± 0.14 vs 0.54 ± 0.14,0.69 ± 0.13 vs 0.59 ± 0.04,P < 0.05),and decreased gradually later. There were significant differences at each time point except 1 h and 2 h,when compared with those in the NC group (0.71 ± 0.14 or 0.69 ± 0.13 vs 0.47 ± 0.10,0.38 ± 0.08 or 0.59 ± 0.04 vs 0.47 ± 0.09,0.25 ± 0.07 or 0.29 ± 0.05 vs 0.46 ± 0.10,0.20 ± 0.06 or 0.20± 0.04 vs 0.43 ± 0.09,P < 0.05),whereas there was no significant difference between BN and SAP groups at each time point. The result of PAF-R protein showed that the change of PAF-R protein in the SAP group and the BN group was consistent with that of PAF-R mRNA. There were significant differences at each time point except 1 h,when compared with those in the NC group (0.90 ± 0.02 or 0.80 ± 0.05 vs 0.48 ± 0.02,1.69 ± 0.06 or 1.58 ± 0.02 vs 0.48 ± 0.03,1.12 ± 0.10 or 0.98 ± 0.03 vs 0.49 ± 0.09,1.04 ± 0.14 or 0.87 ± 0.02 vs 0.52 ± 0.08,0.97 ± 0.16 or 0.90 ± 0.05 vs 0.49 ± 0.10,P < 0.05),whereas there was no significant difference between the BN group and the SAP group. CONCLUSION:PAF-R plays an important role in occurrence and development of SAP. BN52021 exerts biological effects through competitively inhibiting the binding of increased both PAF and PAF-R expression rather than through decreasing PAF-R expression in pancreatic tissues.
基金Supported by Two grants from National Natural Science Foundation of China,No. 30300465 and No. 30772883
文摘AIM:To determine the optimal dosage and mechanism of Ginkgolide B(BN52021) on severe acute pancreatitis(SAP) of rats.METHODS:Seventy male Wistar rats were randomly divided into seven groups(10 for each group).Shamoperation group(SO),SAP model group(SAP),dimethyl sulfoxide(DMSO) contrast group(DMSO),and groups treated with 2.5 mg/kg BN52021(BN1),5 mg/kg BN52021(BN2),10 mg/kg BN52021(BN3),and 20 μg/kg Sandostatin(SS).The SAP model was established in Wistar rats by injecting 5% sodium taurocholate retrogradely into the common bilio-pancreatic duct.The rats of SO,DMSO and BN52021 were injected with 0.9% NaCl,0.5% DMSO and BN52021 through femoral vein 15 min after the operation.The SS group was injected with Sandostatin subcutaneously.All rats were anaesthetized at 6 h after operation,and venous blood was collected to determine the levels of serum amylase and phospholipase A2(PLA2),and pancreas tissue was harvested and stained.RESULTS:There was no significant difference between the SAP and DMSO groups in serum amylase level,PLA2,ascites and pathologic score,but significant difference was found in SAP/DMSO groups compared with those in SO group(P < 0.05) and the levels of serum amylase,PLA2,ascites,and pathologic score were lower in the BN1,BN2,BN3 and SS groups than in the SAP and DMSO groups(P < 0.05).However,among BN1,BN2,BN3 and SS groups,BN2 had the best effect in decreasing the levels of serum amylase and PLA2(P < 0.05).Expression of platelet activating factor(PAF) receptor(PAFR) mRNA and protein showed no significant difference between the SAP and DMSO groups,or among BN1,BN2,BN3 and SS groups,but there was remarkable difference between SAP/DMSO group and SO group(P < 0.05),and expression of PAFR mRNA and protein was higher in the BN1,BN2,BN3 and SS groups than in the SAP and DMSO groups(P < 0.05).PAFR expression was observed in the nucleus and cytoplasm of pancreatic islet cells in Wistar rats by immunohistochemistry.CONCLUSION:By iv injection,5 mg/kg of BN52021 is the optimal dosage for SAP rats.BN52021 may inhibit the interaction/binding of PAF with PAFR.
文摘To explore the effect of Buyang Huanwu Decoction (BHD) on platelet activating factor (PAF) content in arterial blood pre- and post-arterial thrombosis in rats, male Wistar rats were randomly divided into 3 groups, the medicine group treated with BHD, the control group with dexamethasone liquid, and the blank group with distilled water. Oral administration was given for 14 consecutive days, once daily. Model of arterial thrombosis was established in the animals 2 hours after final medication, the blood content of PAF, dry weight (DW) and occlusion time (OT) of thrombus, and dry weight of thrombus/body weight (TW/BW) ratio were observed. Results indicated that BHD could markedly lower the arterial blood content of PAF after thrombosis, increase the OT of thrombus, reduce the dry weight of thrombus and the TW/BW ratio (P
基金Supported by the Key Scientific and Technological Research Foundation of the National 863 Program,No.2003AA208106Medical Outstandard Foundation of Army,No.04J020
文摘AIM： To evaluate the changes in hepatic platelet activating factor （PAF） and its receptors and their effect on portal pressure of cirrhotic rats induced by CCh. METHODS： A model of liver cirrhosis was replicated in rats by intra-peritoneal injection of CCh for 8 wk. We determined the effect of hepatic PAF and its receptor level on portal and arterial pressure by EIA, saturation binding and RT-PCR technique. RESULTS： Compared to control rats, cirrhotic rats had higher hepatic PAF levels and output as well as higher plasma PAF levels （P〈0.01, P〈0.01, P〈0.05, respectively）. Both hepatic PAF receptor mRNA levels and PAF binding were nearly 3-fold greater in cirrhotic rats （P〈0.01）. Portal injection of PAF （1 g/kg WT） increased the portal pressure by 22% and 33% in control and cirrhotic rats, respectively. In contrast, the arterial pressure was decreased in the both groups （54% in control rats and 42% in cirrhotic rats）. Injection of the PAF antagonist BN52021 （5 mg/kg WT） decreased the portal pressure by 16% in cirrhotic rats but had no effect in the control rats. CONCLUSION： The upregulation of the PAF system contributes to hepatic hemodynamic and metabolic abnormalities in drrhosis, and the increased release of PAF into the circulation has impacts on the systemic hemodynamics.
基金the Major Science and Technology Research Fund of the National 863 Program, No. 2003AA208106the Fund for Outstanding Medical Scientists of PLA, No. 04J020
文摘AIM:To determine the platelet-activating factor (PAF) synthesis and its receptor expression in Kupffer cells in rat carbon tetrachloride-induced cirrhosis. METHODS:Kupffer cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium overnight. PAF saturation binding, ET-1 saturation and competition binding were assayed. ET-1 induced PAF synthesis, mRNA expression of PAF, preproendothelin-1, endothelin A (ETA) and endothelin B (ETB) receptors were also determined. RESULTS:A two-fold increase of PAF synthesis (1.42 ± 0.14 vs 0.66 ± 0.04 pg/μg DNA) and a 1.48-fold increase of membrane-bound PAF (1.02 ± 0.06 vs 0.69 ± 0.07 pg/μg DNA) were observed in activated Kupffer cells of cirrhotic rats. The application of ET-1 to Kupffer cells induced PAF synthesis in a concentration-dependent manner in both cirrhotic and normal rats via ETB receptor, but PAF synthesis in the activated Kupffer cells was more effective than that in the normal Kupffer cells. In activated Kupffer cells, PAF receptor expression and PAF binding capacity were markedly enhanced. Activated Kupffer cells raised the [125I]-ET-1 binding capacity, but changed neither the affinity of the receptors, nor the expression of ETA receptor. CONCLUSION:Kupffer cells in the course of CCl4-induced cirrhosis are the main source of increased PAF. ET-1 is involved endogenously in stimulating the PAF synthesis in activated Kupffer cells via ETB receptor by paracrine. ETA receptor did not appear in activated Kupffer cells, which may exacerbate the hepatic and extrahepatic complications of cirrhosis.
文摘Objective The mechanism through which platelet activating factor （PAF） induces cardiac electrical activity and arrhythmia is not well understood and previous studies have suggested a potential involvement of ion channels in its action. The present study was aimed to clarify the role of PAF in fatal arrhythmias following acute myocardia infarction （AMI） and the underlying mechanism. Methods （1） Blood PAF levels were measured among 72 AMI patients at the time of diagnosis with AMI and 48 h later, and their electrocardiogram （ECG） was recorded continuously. （2） Ischemia simulation and surface electrocardiogram were conducted in 20 pigs and their PAF levels were measured. （3） PAF perfusion and standard microelectrode recording were performed on guinea pig papillarymuscles. Results In both humans and pigs, elevated PAF levels were detected in AMI and simulated ischemia, respectively, and even higher PAF levels were found when fatal arrhythmias occurred. In guinea pig myocardium, PAF induced a shortening of action potential duration at 90% level of repolarization （APD 90 ）under non-ischemic conditions and a more pronounced shortening under early simulated ischemic conditions. Conclusion AMI and ischemia are associated with increased PAF levels in humans and pigs, which are further raised when fatal arrhythmia follows. The effects of PAF on the myocardium may be mediated by multiple ion channels.
基金The Key Scientific and Technological ResearchFoundation of the National 863 Program, No. 2003AA208106Medical Outstandard Foundation of Army, No. 04J020
文摘AIM: To determine platelet activating factor (PAF) receptor expression in cirrhotic hepatic stellate cells.METHODS: Hepatic stellate cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium after overnight culture. We determined the PAF receptor in hepatic stellate cells by saturation binding technique and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), and the effects of PAF and its antagonist BN52021 on prostaglandin E2 (PGE2) release by stellate cells.RESULTS: Scatchard analysis indicated the presence of PAF receptor with dissociation constant (Kd) of 4.66 nmol/L and maximum binding capacity (Bmax) of 24.65 fmol/μg in cirrhotic stellate cells. Compared with the control, the maximum PAF binding capacity increased significantly (Bmax: 24.65 ± 1.96 fmol/μg. DNA, R = 0.982 vs 5.74 ± 1.55 fmol/μg. DNA, R = 0.93; P < 0.01), whereas receptor affinity had no significant difference (Kd of 4.66 ± 0.33 nmol/L for the cirrhosis and 3.51 ± 0.26 nmol/L for the control; P > 0.05). Consistent with the receptor binding data, the mRNA expression of PAF receptor was increased significantly in cirrhotic stellate cells. PAF in a concentration-dependent manner induced PGE2 synthesis in cirrhotic hepatic stellate cells, but the effects were blocked significantly by BN52021.CONCLUSION: Cirrhosis sensitizes hepatic stellate cells to PAF by elevating its receptor level and hepatic stellate cells maybe potential effectors of PAF induced portal hypertension.
文摘AIM To evaluate platelet activation markers in psoriasis patients, compared to controls, and investigate their association with the inflammatory burden of psoriasis.METHODS Forty psoriatic patients without cardiovascular disease,and 12 healthy controls were subjected to measurement of baseline platelet CD62 P, CD63 and CD42 b expression, platelet-leukocyte complexes, i.e., platelet-monocyte complexes(PMC), platelet-neutrophil complexes(PNC) and platelet-lymphocyte complexes, and concentrations of platelet-derived microparticles(PMPs) using flow cytometry. Both larger-size(0.5-0.9 μm) and smallersize(< 0.5 μm) PMPs were determined. Serum interleukin(IL)-12 and IL-17 levels were also measured by enzyme-linked immunosorbent assay. The severity of psoriasis was evaluated by the Psoriasis Area Severity Index(PASI).RESULTS PMP concentrations were significantly higher in psoriasis patients than controls [mean±standard error of mean(SEM): 22±5/μL vs 11±6/μL; P=0.018), for both smaller-size(10±2/μL vs 4±2/μL; P=0.033) and larger-size(12±3/μL vs 6±4/μL; P=0.014) PMPs. Platelet CD62 P, CD63 and CD42 b expression and circulating PMC and PNC were similar between the two groups. Lower circulating PLC were observed in psoriasis patients compared to controls(mean±SEM: 16%±3% vs 23%±6%; P=0.047). Larger-size PMPs were related with IL-12 levels(P<0.001) and smaller-size PMPs with both IL-12 and IL-17 levels(P<0.001). Total PMPs also correlated with IL-12(P<0.001). CD63 expression was positively correlated with both IL-12 and IL-17(P<0.05). Increased PASI score was associated with increased levels of larger-size PMPs(r=0.45; P=0.011) and increased CD63 expression(r=0.47; P<0.01).CONCLUSION PMPs, known to be predictive of cardiovascular outcomes, are increased in psoriasis patients, and associated with high inflammatory disease burden. Enhanced platelet activation may be the missing link leading to cardiovascular events in psoriatic patients.
文摘Objective.To establish a flow cytometric internal standard method for counting platelet-derived microparti-cles(PMPs)and to study its clinical significance. Methods. PMPs suspension(platelet poor plasma,PPP) was extracted by gradual centrifugation. According to the size of PMPs,3 μm and 0.8μm latex beads were used as internal standards for the quantitation. PMPs were counted by adjusting flow cytometric discrimination and voltage of forward scatter and side scatter. Results. In 30 healthy donors,the average concentration of resting PMPs was(1.2×105±5.7×104 )/ml and that of activated PMPs was(1.6×106±9.1×105)/ml. Compared with healthy donors,PMPs mean value was significantly higher(P< 0.001)in 18 patients with coronary artery disease,12 with acute cerebral infraction and 23 with chronic renal failure[the average PMPs concentration,( 6.1×105±2.5×105 )/ml, ( 6.8×105±3.4×105)/ml and(5.9×105±3.1×105)/ml respectively]. However,no significant difference in PMPs concentration was observed in 25 patients with acute leukemia and severe thrombocytopenia during the aplastic phase after chemotherapy [1.3×105±6.1×104)/ml,(P >0.05)] .Conclusions. PMPs is a useful indicator in monitoring platelet activation,and plays an important role in thrombotic disease. By flow cytometric internal standard method,PMPs can be counted rapidly and accurately,which may be very helpful in interlaboratory comparative studies.
