How does measurement of platelet P-selectin compare with other methods of measuring platelet function as a means of determining the effectiveness of antiplatelet therapy?

Designing an experimental method for assessing biocompatibility of circuit coatings using biomarkers for platelet activation during cardiopulmonary bypass

INTRODUCTION

Cardiopulmonary bypass is an essential component of cardiothoracic surgeries. However, significant complications such as systemic inflammatory response syndrome (SIRS) resulting from cardiopulmonary bypass (CPB) are a common occurrence due to contact between circulating blood and foreign surfaces that leads to platelet activation. It is suggested that different available CPB circuit coatings can potentially reduce platelet activation. However, there have been no published evidence-based reports confirming these claims. In addition, there is no well-established protocol for studying platelet activation biomarkers during CPB in vitro in a laboratory setting.

METHODS

CPB was simulated in the laboratory using bovine blood in two different types of coated CPB circuits: Trillium® Biosurface by Medtronic, and XcoatingTM Surface by Terumo. Fresh bovine blood samples were collected and circulated through the CPB circuit following the standard protocol used in the operation rooms. Blood samples were then collected at 5 min, 30 min, and 55 min during the circulation. Blood plasmas were separated and subjected to enzyme-linked immunosorbent assay to measure most established platelet activation markers P-selectin, Platelet Factor 4 (PF4), Glycoprotein IIb/IIIa (GPIIb/IIIa), and β-thromboglobulin (β-TG) at different time points.

RESULTS

The biomarker values at 30 min and 55 min were compared to the base values at 5 min for each type of CPB circuit. The results of the means from all measured biomarkers showed data measurements that indicated no significant variability within each coating. All collected data points fell within ±2 SD of the means, which was considered acceptable variations across technical replicates.  Conclusion: In this study, we were able to establish an in vitro protocol in the laboratory setting that is precise and reliable with minimum intra-variability. This established protocol will allow for future studies in which different coated CPB circuits can be compared for their effectiveness in blocking platelet activation during the CPB.

Relevant detection indicator of prethrombotic state in patients with primary hypertension

BACKGROUND

Hypertension is a common chronic disease that affects many people worldwide. Only a few reports related to the exploration of relevant indicators of the prethrombotic state in patients with primary hypertension (PH) in clinical settings were available.

AIM

To detect prethrombotic state-related indicators in patients with PH and analyze their differences in different patient populations to provide a laboratory basis for the clinical prevention and control of hypertensive thrombotic diseases.

METHODS

The general data of patients with PH who attended the Department of Cardiovascular Medicine, The First Affiliated Hospital of Jiangxi Medical College, from January 2022 to December 2022 were collected retrospectively. The patients were divided into three groups of 40 patients each according to the Grade of PH: Grade 1, Grade 2, and Grade 3 hypertension experimental group. The baseline data of 40 volunteers, who underwent physical examination in our hospital but were not diagnosed with PH during the same period, were included in the control group. The relevant indicators of prethrombotic state of the participants were compared, and mainly included inflammation-related indicators, hemorheology-related indicators, and coagulation function related indicators. The relationship between the aforementioned indicators and the progression of PH was analyzed.

RESULTS

No significant differences were observed in age, sex, diabetes mellitus, smoking history, drinking history, body mass index, New York Heart Association functional classification, or the course of hypertension among the four groups (P > 0.05). The expressions of high-sensitivity C-reactive protein (hs-CRP), thrombomodulin (TM), hematocrit (Hct), erythrocyte sedimentation rate (ESR), P-selectin on platelet surface (CD62P), and fibrinogen (FIB) in the control group were < Grade 1 hypertension group < Grade 2 hypertension group < Grade 3 hypertension group, and the expressions of platelet (PLT), activated partial thromboplastin time (APTT), prothrombin (PT), and plasma thrombin time (TT) in the control group was > Grade 1 hypertension group > Grade 2 hypertension group > Grade 3 hypertension group, and the difference was statistically significant (P < 0.05). The results of the multivariate logistic regression model showed that the expression of hs-CRP, TM, Hct, ESR, CD62P, PLT, APTT, PT, TT, and FIB in the included participants was related to the progression of PH. Among these, high expression of hs-CRP, TM, Hct, ESR, CD62P, APTT, PT, and TT, and low expression of PLT and FIB were risk factors for PH (OR > 1, P < 0.05). The results of the receiver operating characteristic curve analysis showed that the area under the curve of hs-CRP, TM, ESR, CD62P, APTT, PT, TT, and FIB for the prediction of PH were > 0.80, and the prediction value was ideal. Linear correlation analysis with bivariate Spearman showed that hs-CRP, TM, Hct, ESR, CD62P, APTT, PT, and TT were positively correlated with each other (r > 0, P < 0.05); PLT and FIB were negatively correlated with hs-CRP, TM, Hct, ESR, CD62P, APTT, PT, and TT (r < 0, P < 0.05); and PLT and FIB were positively correlated (r > 0, P < 0.05). Linear correlation analysis using bivariate Spearman showed that hs-CRP, TM, Hct, ESR, CD62P, and FIB were positively correlated with each other (r > 0, P < 0.05), whereas PLT, APTT, PT, and TT were negatively correlated with hs-CRP, TM, Hct, ESR, CD62P, and FIB (r < 0, P < 0.05). There was a positive correlation between PLT, APTT, PT, and TT (r > 0, P < 0.05).

CONCLUSION

The relevant indicators of the prethrombotic state in patients with PH, such as hs-CRP, TM, Hct, ESR, CD62P, PLT, APTT, PT, TT, and FIB, showed differences. High expression of hs-CRP, TM, Hct, ESR, CD62P, and FIB, and low expression of PLT, APTT, PT, and TT are the keys to the occurrence, progression, and thrombotic state of PH. Based on the above serum indicators' expression in patients, targeted interventions can be administered to patients with abnormal expression levels to control the progression of their disease and reduce the risk of developing a prethrombotic state.

Clinical Outcomes of Individualized Antiplatelet Therapy Based on Platelet Function Test in Patients After Percutaneous Coronary Intervention: A Systematic Review and Meta-analysis

ABSTRACT

Platelet function test (PFT) is universally used to assess platelet reactivity to antiplatelet drugs in patients after percutaneous coronary intervention (PCI). However, it remains controversial whether individualized antiplatelet therapy guided by PFT can improve the prognosis in patients after PCI. This meta-analysis was conducted to explore the efficacy and safety of individualized antiplatelet therapy guided by PFT in patients after PCI. Studies that compared PFT-guided antiplatelet therapy with standard antiplatelet therapy were researched. The risks of major adverse cardiovascular and cerebrovascular events (MACCE) and major bleeding events were assessed. Pooled odds ratios (ORs) with 95% CIs were obtained. Finally, a total of 16,835 patients from 22 studies met the criteria and were included in the meta-analysis. Compared with standard antiplatelet therapy, individualized antiplatelet therapy guided by PFT significantly decreased the risk of MACCE (OR: 0.58, 95% CI: 0.43-0.77) in patients after PCI. There was no significant difference in major bleeding events (OR: 0.85, 95% CI: 0.70-1.05, P = 0.13). This study identified that PFT-guided individualized antiplatelet therapy could reduce the incidence of MACCE without increasing the risk of hemorrhage in patients after PCI.

Diurnal Oscillations of Fibrinolytic Parameters in Patients with Acute Myocardial Infarction and Their Relation to Platelet Reactivity: Preliminary Insights

There is limited information about diurnal changes in fibrinolysis parameters after acute myocardial infarction (AMI) and their relationship with on-treatment platelet reactivity. The aim of this study was to assess tissue plasminogen activator (t-PA), plasminogen activator inhibitor type-1 (PAI-1), α2-antiplasmin (α2-AP) activity, and plasmin-antiplasmin (PAP) complexes in 30 AMI patients taking dual antiplatelet therapy (DAPT), i.e., acetylsalicylic acid and clopidogrel. Fibrinolytic parameters were assessed at four time points (6 a.m., 10 a.m., 2 p.m., and 7 p.m.) on the third day after AMI using immunoenzymatic methods. Moreover, platelet reactivity was measured using multiple-electrode aggregometry, to assess potential differences in fibrinolytic parameters in low/high on-aspirin platelet reactivity and low/high on-clopidogrel platelet reactivity subgroups of patients. We detected significant diurnal oscillations in t-PA and PAI-1 levels in the whole study group. However, PAP complexes and α2-AP activity were similar at the analyzed time points. Our study reveals a potential impact of DAPT on the time course of fibrinolytic parameters, especially regarding clopidogrel. We suggest the presence of diurnal variations in t-PA and PAI-1 concentrations in AMI patients, with the highest levels midmorning, regardless of platelet reactivity. Significantly elevated levels of PAI-1 during the evening hours in clopidogrel-resistant patients may increase the risk of thrombosis.

Emerging roles of platelets in cancer biology and their potential as therapeutic targets

The main role of platelets is to control bleeding and repair vascular damage via thrombosis. They have also been implicated to promote tumor metastasis through platelet-tumor cell interactions. Platelet-tumor cell interactions promote tumor cell survival and dissemination in blood circulation. Tumor cells are known to induce platelet activation and alter platelet RNA profiles. Liquid biopsies based on tumor-educated platelet biomarkers can detect tumors and correlate with prognosis, personalized therapy, treatment monitoring, and recurrence prediction. Platelet-based strategies for cancer prevention and tumor-targeted therapy include developing drugs that target platelet receptors, interfere with the release of platelet particles, inhibit platelet-specific enzymes, and utilize platelet-derived “nano-platelets” as a targeted drug delivery platform for tumor therapy. This review elaborates on platelet-tumor cell interactions and the molecular mechanisms and discusses future research directions for platelet-based liquid biopsy techniques and platelet-targeted anti-tumor strategies.

Platelet function and microvesicle generation in patients with hemophilia A

Our results do not support any effect of FVIII on platelet function in patients with severe HA treated under the regime of prophylaxis.

Prostaglandin E1 effects on CD62p and PAC-1 in patients with sudden sensorineural hearing loss

PERSPECTIVES

To evaluate the treatment outcome of vasodilator prostaglandin E1 (PGE1) in treating sudden sensorineural hearing loss (SSNHL) and to determine its effects on platelet activation, as reflected by changes in CD62p and PAC-1.

METHODS

We prospectively enrolled 60 patients with confirmed SSNHL and randomly divided them into two groups: the SSNHL group received regular therapy, and the SSNHL-PGE1 group received additional intravenous injection of PGE1. After 14 days of treatment, we measured clinical improvement and CD62p-positive and PAC-1-positive platelets. 30 healthy medical staff members were included as a control group.

RESULTS

The SSNHL patients had significantly higher levels of CD62p-positive or PAC-1 positive platelets than the healthy subjects. The ratios of CD62p positive or PAC-1 positive platelets significantly decreased after the two treatments. The average pure tone (PTA) hearing thresholds decreased to 26.51 ± 12.65 dB in SSNHL-PGE1 group after treatment, which was significantly lower than that of the SSNHL group (34.46 ± 10.35 dB). Patients with initial severe or profound hearing loss (PTA ≥ 71 dB) had better hearing improvement on PGE1 than on the regular treatment. Patients in the SSNHL-PGE1 treatment group had significantly lower CD62p and PAC-1 levels than those in the SSNHL group. Patients with higher initial positive CD62p and PAC-1 ratios tended to have higher potential of clinical improvement and hearing gains after PGE1 treatment. Initial CD62p and PAC-1 levels were significantly correlated with hearing thresholds in patients with SSNHL.

CONCLUSION

PGE1 application could improve treatment efficacy and suppress excessive platelet activation in patients with SSNHL.

Measurement of platelet p-selectin expression by flow cytometry in patients with acute ischemic stroke

Aims: The aim of this study was to asses the platelet activation in the acute phase of ischemic stroke and transient ischemic attack (TIA) by defining p-selectin (CD62) expression by flow cytometry in vivo – without stimulation with agonists. We also studied whether antiplatelet therapy supresses the levels of baseline p-selectin expression and verified if there is a correlation between platelet CD62 expression and the type of ischemic stroke.

Methods: We determined the expression of platelet surface p-selectin using whole-blood flow cytometry within the first 48-hours after onset of cerebral symptoms in patients with atherothrombotic and lacunar ischemic stroke and in healthy volunteers. We studied the realationship between antiplatelet medication and the type of ischemic stroke to baseline p-selectin expression.

Results: Patients with acute cerebral ischemia have an excess of circulating platelets that express p-selectin, compared to healthy volunteers. The difference between average p-selectin expression in the group of healthy volunteers and the group of patients with stroke was statistically significant (p-value < 0,000001). Patients with stroke without antiplatelet medication showed a higher p-selectin expression than patients with antiplatelet medication (ASA, CLP, or ASA and CLP), hovewer, the difference was not statistically significant. There is no relationship between CD62 expression and the type of stroke.

Conclusions: We can conclude that p-selectin is a highly sensitive blood biomarker of increased platelet activation. Antiplatelet therapy suppresses baseline p-selectin expression only minimally, insignificantly according to our results.