Objective To evaluate whether Vibrio vulnificus secreted exotoxin-hemolysin (VVH) can activate platelet, an important blood immune cell, and to explore the possible molecular mechanism of platelet activation by VVH. Methods Transcriptomics and immunohistochemistry were used to analyze whether Vibrio vulnificus infection caused platelet activation in mice. Then, flow cytometry was used to identify whether VVH was the main stimulator of platelet activation. Naturally expressed VVH toxin was purified and prepared. The effects of extracellular and intracellular Ca²⁺ signal inhibitors on VVH activated platelets were evaluated by flow cytometry and Western blotting. The immune activation effect of VVH in the early stage of Vibrio vulnificus infection was analyzed in vivo. Results VVH was the main stimulator of platelet activation in Vibrio vulnificus culture supernatant. Natural VVH can induce the increase of P-selectin (CD62P) on platelet surface, the formation of platelet-neutrophil complex (PNC), and the release of platelet microvesicles. The activation mechanism may be related to the VVH pore-dependent Ca²⁺-calmodulin (CaM) -myosin light chain kinase (MLCK) signaling pathway, which led to the release of platelet alpha particles and cascade activation of platelets. In a mouse model of ALD infected by Vibrio vulnificus gavage, VVH was strongly associated with platelet activation. Conclusion This study shows that VVH is an important platelet activating molecule in the early stage of Vibrio vulnificus infection, and its induction of platelet activation may be related to the pathogenic process.
Animals ; Platelet Activation/drug effects* ; Hemolysin Proteins/pharmacology* ; Vibrio vulnificus/metabolism* ; Mice ; Blood Platelets/drug effects* ; Vibrio Infections/immunology* ; P-Selectin/metabolism* ; Bacterial Proteins ; Female

OBJECTIVE: To compare and analyze the changes of aggregation rate and routine parameters of platelets stored in temperature cycle, cold storage at 4 ℃ and oscillating storage at 22 ℃, so as to provide more experimental data for platelet preservation methods. METHODS: Blood samples were collected at 5 time points on the 1^st, 2^nd, 3^rd, 4^th and 6^th day after platelet cycling preservation at temperature, cold storage at 4 ℃, and oscillating storage at 22 ℃. Platelet maximum aggregation rate (MAR) and routine parameters including platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW) and platelet-larger cell ratio (P-LCR) were detected. RESULTS: The platelet MAR of three groups showed a significant decrease trend with the preservation time, the fastest decrease was in the 22 ℃ group, the slowest was in the 4 ℃ group, and the temperature cycle group was between the two groups. On the 3^rd day of preservation, the platelet MAR in 4 ℃ group was still in the normal range (MAR>60%), while in temperature cycle group was about 50%, and in 22 ℃ group was the lowest. On the 4^th day of preservation, platelet MAR in all the three groups was lower than 50%, and that in temperature cycle group was significantly lower than in 4 ℃ group but higher than in 22 ℃ group (both P < 0.05). On the 6^th day of preservation, platelet MAR in the temperature cycle group was significantly lower than that in the 4 ℃ group ( P <0.05), but there was no statistically significant difference compared to 22 ℃ group (P >0.05). PLT values in the three groups were all significantly decreased with the preservation time extension, and were significantly lower than those in the early stage of preservation within 6 days (all P < 0.05). PDW in temperature cycle group had no significant change within 6 days of preservation, but MPV and P-LCR were significantly increased. MPV, PDW and P-LCR all decreased significantly in 4 ℃ group within 6 days of preservation but increased in 22 ℃ group. Under the same storage days, PLT value of temperature cycle group had no significant difference with that of 4 ℃ group and 22 ℃ group, while MPV, PDW and P-LCR values were significantly higher than 4 ℃ group but lower than 22 ℃ group (all P < 0.05). CONCLUSION The aggregation function and routine parameters changes of temperature circulating preserved platelets are between 4 and 22 ℃.
Humans ; Platelet Aggregation ; Blood Preservation/methods* ; Temperature ; Blood Platelets ; Platelet Count ; Mean Platelet Volume ; Cryopreservation/methods* ; Cold Temperature

OBJECTIVE: To investigate the effects of oridonin on platelet function and related mechanisms. METHODS: Washed platelets from healthy adults and mice were incubated with different concentrations of oridonin (2.5, 5 and 10 μmol/L) in vitro . The surface expression level of P-selectin and the activation of integrin αIIbβ3 in platelets were detected by flow cytometry, and the aggregation ability of platelets under the stimulation by various agonists was detected by light transmission aggregometry. The expression of P-AKT (Ser473) was detected by protein immunoblotting. Arterial thrombosis model was established in mice with mesenteric injury induced by ferric chloride, and tail hemorrhage model was established by cutting off the tail of mice. The effect of intraperitoneal injection of oridonin (10 mg/kg) on thrombosis and haemostasis was tested. RESULTS: Oridonin inhibited platelet P-selectin expression and integrin αIIbβ3 activation. In the presence of different stimulants, oridonin inhibited platelet aggregation in a concentration-dependent manner. The phosphorylation level of AKT Ser473 was reduced in the groups treated with different concentrations of oridonin. Oridonin significantly prolonged the time of mesenteric artery thrombosis in mice, but did not affect the tail bleeding time. CONCLUSION Oridonin inhibits platelet activation, aggregation, and thrombosis by inhibiting AKT phosphorylation, and may be used as a potential antiplatelet drug.
Diterpenes, Kaurane/pharmacology* ; Animals ; Mice ; Blood Platelets/drug effects* ; Platelet Aggregation/drug effects* ; P-Selectin/metabolism* ; Thrombosis ; Platelet Glycoprotein GPIIb-IIIa Complex/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Humans ; Phosphorylation ; Platelet Activation/drug effects*

OBJECTIVE: To investigate the effect of zedoarondiol on neovascularization of atherosclerotic (AS) plaque by exosomes experiment. METHODS: ApoE^-/- mice were fed with high-fat diet to establish AS model and treated with high- and low-dose (10, 5 mg/kg daily) of zedoarondiol, respectively. After 14 weeks, the expressions of anti-angiogenic protein thrombospondin 1 (THBS-1) and its receptor CD36 in plaques, as well as platelet activation rate and exosome-derived miR-let-7a were detected. Then, zedoarondiol was used to intervene in platelets in vitro, and miR-let-7a was detected in platelet-derived exosomes (Pexo). Finally, human umbilical vein endothelial cells (HUVECs) were transfected with miR-let-7a mimics and treated with Pexo to observe the effect of miR-let-7a in Pexo on tube formation. RESULTS: Animal experiments showed that after treating with zedoarondiol, the neovascularization density in plaques of AS mice was significantly reduced, THBS-1 and CD36 increased, the platelet activation rate was markedly reduced, and the miR-let-7a level in Pexo was reduced (P<0.01). In vitro experiments, the platelet activation rate and miR-let-7a levels in Pexo were significantly reduced after zedoarondiol's intervention. Cell experiments showed that after Pexo's intervention, the tube length increased, and the transfection of miR-let-7a minics further increased the tube length of cells, while reducing the expressions of THBS-1 and CD36. CONCLUSION Zedoarondiol has the effect of inhibiting neovascularization within plaque in AS mice, and its mechanism may be potentially related to inhibiting platelet activation and reducing the Pexo-derived miRNA-let-7a level.
Animals ; MicroRNAs/genetics* ; Exosomes/drug effects* ; Plaque, Atherosclerotic/genetics* ; Neovascularization, Pathologic/genetics* ; Human Umbilical Vein Endothelial Cells/metabolism* ; Humans ; Blood Platelets/drug effects* ; Apolipoproteins E/deficiency* ; Thrombospondin 1/metabolism* ; CD36 Antigens/metabolism* ; Platelet Activation/drug effects* ; Male ; Mice ; Mice, Inbred C57BL

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.
DNA, Mitochondrial/metabolism* ; Mouth Mucosa/pathology* ; Hypoxia/immunology* ; Methyltransferases/metabolism* ; Blood Platelets/metabolism* ; Animals ; Periodontitis/immunology* ; Humans ; Platelet Activation ; Mice

Objective To examine the antiplatelet effect of ticagrelor by microfluidic chip and flow cytometry under shear stress in vitro. Methods Microfluidic chip was used to examine the effect of ticagrelor on platelet aggregation at the shear rates of 300/s and 1500/s.We adopted the surface coverage of platelet aggregation to calculate the half inhibition rate of ticagrelor.The inhibitory effect of ticagrelor on ADP-induced platelet aggregation was verified by optical turbidimetry.Microfluidic chip was used to construct an in vitro vascular stenosis model,with which the platelet reactivity under high shear rate was determined.Furthermore,the effect of ticagrelor on the expression of fibrinogen receptor (PAC-1) and P-selectin (CD62P) on platelet membrane activated by high shear rate was analyzed by flow cytometry. Results At the shear rates of 300/s and 1500/s,ticagrelor inhibited platelet aggregation in a concentration-dependent manner,and the inhibition at 300/s was stronger than that at 1500/s (both P<0.001).Ticagrelor at a concentration ≥4 μmol/L almost completely inhibited platelet aggregation.The inhibition of ADP-induced platelet aggregation by ticagrelor was similar to the results under flow conditions and also in a concentration-dependent manner.Ticagrelor inhibited the expression of PAC-1 and CD62P. Conclusion We employed microfluidic chip to analyze platelet aggregation and flow cytometry to detect platelet activation,which can reveal the responses of different patients to ticagrelor.
Humans ; Ticagrelor/pharmacology* ; Platelet Aggregation Inhibitors/pharmacology* ; Flow Cytometry/methods* ; Microfluidics ; Platelet Aggregation

OBJECTIVE: To study the effect of gradient shear stress on platelet aggregation by microfluidic chip Technology. METHODS: Microfluidic chip was used to simulate 80% fixed stenotic microchannel, and the hydrodynamic behavior of the stenotic microchannel model was analyzed by the finite element analysis module of sollidwork software. Microfluidic chip was used to analyze the adhesion and aggregation behavior of platelets in patients with different diseases, and flow cytometry was used to detect expression of the platelet activation marker CD62p. Aspirin, Tirofiban and protocatechuic acid were used to treat the blood, and the adhesion and aggregation of platelets were observed by fluorescence microscope. RESULTS: The gradient fluid shear rate produced by the stenosis model of microfluidic chip could induce platelet aggregation, and the degree of platelet adhesion and aggregation increased with the increase of shear rate within a certain range of shear rate. The effect of platelet aggregation in patients with arterial thrombotic diseases were significantly higher than normal group (P<0.05), and the effect of platelet aggregation in patients with myelodysplastic disease was lower than normal group (P<0.05). CONCLUSION The microfluidic chip analysis technology can accurately analyze and evaluate the platelet adhesion and aggregation effects of various thrombotic diseases unde the environment of the shear rate, and is helpful for auxiliary diagnosis of clinical thrombotic diseases.
Humans ; Microfluidics ; Platelet Adhesiveness ; Platelet Aggregation ; Blood Platelets/metabolism* ; Platelet Aggregation Inhibitors/pharmacology* ; Platelet Activation/physiology* ; Thrombosis

OBJECTIVE: To explore the regulation of mitochondria on platelet apoptosis and activation, and the relationship between platelet apoptosis and activation. METHODS: Platelets were isolated from peripheral venous blood of healthy volunteers. Cyclosporin A (CsA), which has a protective effect on the function of platelet mitochondria, BAPTA, which can chelate calcium ions across membranes in platelets, and NAC, an antioxidant that reduces the level of intracellular reactive oxygen species, were selected for coincubation with washed platelets, respectively. By flow cytometry, platelet aggregator was used to detect the changes of platelet mitochondrial function and platelet activation indexes after different interventions. RESULTS: H89, staurosporine, and A23187 led to platelet mitochondrial abnormalities, while CsA could effectively reverse the decline of platelet mitochondrial membrane potential caused by them. Antioxidant NAC could reverse platelet mitochondrial damage correspondingly, and completely reverse platelet shrinkage and phosphatidylserine eversion induced by H89. BAPTA, prostaglandin E1, acetylsalicylic acid and other inhibitors could not reverse the decline of platelet mitochondrial membrane potential. CONCLUSION Mitochondrial function plays an important role in platelet apoptosis and activation. Abnormal mitochondrial function causes the imbalance of reduction/oxidation state in platelets, which leads to platelet apoptosis. Platelet apoptosis and activation are independent signal processes.
Humans ; Blood Platelets/metabolism* ; Antioxidants/pharmacology* ; Mitochondria/physiology* ; Platelet Activation ; Apoptosis ; Membrane Potential, Mitochondrial ; Reactive Oxygen Species/pharmacology*

OBJECTIVE: To explore whether the differentiation of vascular stem cells (VSC) into smooth muscle cells (SMC) in aortic dissection (AD) is dysregulated, and to verify the role of Notch3 pathway in this process. METHODS: Aortic tissues were obtained from AD patients undergoing aortic vascular replacement and heart transplant donors at Department of Cardiovascular Surgery, Guangdong Provincial People's Hospital Affiliated to Southern Medical University. VSC were isolated by enzymatic digestion and c-kit immunomagnetic beads. The cells were divided into normal donor-derived VSC group (Ctrl-VSC group) and AD-derived VSC group (AD-VSC group). The presence of VSC in the aortic adventitia was detected by immunohistochemical staining, and VSC was identified by stem cell function identification kit. The differentiation model of VSC into SMC established in vitro was induced by transforming growth factor-β1 (10 μg/L) for 7 days. They were divided into normal donor VSC-SMC group (Ctrl-VSC-SMC group), AD VSC-SMC group (AD-VSC-SMC group) and AD VSC-SMC+Notch3 inhibitor DAPT group (AD-VSC-SMC+DAPT group,DAPT 20 μmol/L was added during differentiation induction). The expression of contractile marker Calponin 1 (CNN1) in SMC derived from aortic media and VSC were detected by immunofluorescence staining. The protein expressions of contractile markers α-smooth muscle actin (α-SMA), CNN1 as well as Notch3 intracellular domain (NICD3) in SMC derived from aortic media and VSC were detected by Western blotting. RESULTS: Immunohistochemical staining showed there was a population of c-kit-positive VSC in the adventitia of aortic vessels, and VSC from both normal donors and AD patients had the ability to differentiate into adipocytes and chondrocytes. Compared with normal donor vascular tissue, the expressions of SMC markers α-SMA and CNN1 of tunica media contraction in AD were down-regulated (α-SMA/β-actin: 0.40±0.12 vs. 1.00±0.11, CNN1/β-actin: 0.78±0.07 vs. 1.00±0.14, both P < 0.05), while the protein expression of NICD3 was up-regulated (NICD3/GAPDH: 2.22±0.57 vs. 1.00±0.15, P < 0.05). Compared with Ctrl-VSC-SMC group, the expressions of contractile SMC markers α-SMA and CNN1 were down-regulated in AD-VSC-SMC group (α-SMA/β-actin: 0.35±0.13 vs. 1.00±0.20, CNN1/β-actin: 0.78±0.06 vs. 1.00±0.07, both P < 0.05), the protein expression of NICD3 was up-regulated (NICD3/GAPDH: 22.32±1.22 vs. 1.00±0.06, P < 0.01). Compared with AD-VSC-SMC group, the expressions of contractile SMC markers α-SMA, CNN1 were up-regulated in AD-VSC-SMC+DAPT group (α-SMA/β-actin: 1.70±0.07 vs. 1.00±0.15, CNN1/β-actin: 1.62±0.03 vs. 1.00±0.02, both P < 0.05). CONCLUSIONS Dysregulation of VSC differentiation into SMC occurs in AD, while inhibition of Notch3 pathway activation can restore the expression of contractile proteins in VSC-derived SMC in AD.
Humans ; Actins ; Platelet Aggregation Inhibitors ; Signal Transduction ; Aortic Dissection ; Cell Differentiation ; Myocytes, Smooth Muscle ; Stem Cells

Objective: To investigate current use of oral anticoagulant (OAC) therapy and influencing factors among coronary artery disease (CAD) patients with nonvalvular atrial fibrillation (NVAF) in China. Methods: Results of this study derived from "China Atrial Fibrillation Registry Study", the study prospectively enrolled atrial fibrillation (AF) patients from 31 hospitals, and patients with valvular AF or treated with catheter ablation were excluded. Baseline data such as age, sex and type of atrial fibrillation were collected, and drug history, history of concomitant diseases, laboratory results and echocardiography results were recorded. CHA₂DS₂-VASc score and HAS-BLED score were calculated. The patients were followed up at the 3rd and 6th months after enrollment and every 6 months thereafter. Patients were divided according to whether they had coronary artery disease and whether they took OAC. Results: 11 067 NVAF patients fulfilling guideline criteria for OAC treatment were included in this study, including 1 837 patients with CAD. 95.4% of NVAF patients with CAD had CHA₂DS₂-VASc score≥2, and 59.7% of patients had HAS-BLED≥3, which was significantly higher than NVAF patients without CAD (P<0.001). Only 34.6% of NVAF patients with CAD were treated with OAC at enrollment. The proportion of HAS-BLED≥3 in the OAC group was significantly lower than in the no-OAC group (36.7% vs. 71.8%, P<0.001). After adjustment with multivariable logistic regression analysis, thromboembolism(OR=2.48,95%CI 1.50-4.10,P<0.001), left atrial diameter≥40 mm(OR=1.89,95%CI 1.23-2.91,P=0.004), stain use (OR=1.83,95%CI 1.01-3.03, P=0.020) and β blocker use (OR=1.74,95%CI 1.13-2.68,P=0.012)were influence factors of OAC treatment. However, the influence factors of no-OAC use were female(OR=0.54,95%CI 0.34-0.86,P=0.001), HAS-BLED≥3 (OR=0.33,95%CI 0.19-0.57,P<0.001), and antiplatelet drug(OR=0.04,95%CI 0.03-0.07,P<0.001). Conclusion: The rate of OAC treatment in NVAF patients with CAD is still low and needs to be further improved. The training and assessment of medical personnel should be strengthened to improve the utilization rate of OAC in these patients.
Humans ; Female ; Male ; Atrial Fibrillation/drug therapy* ; Coronary Artery Disease/complications* ; Anticoagulants/therapeutic use* ; Platelet Aggregation Inhibitors/therapeutic use* ; Risk Factors ; China ; Administration, Oral ; Stroke