Relationships of glycoproteins IIb-IIIa and Ib content with mean platelet volume and their genetic polymorphisms

Meta-analysis of peripheral mean platelet volume in patients with mental disorders: Comparisons in depression, anxiety, bipolar disorder, and schizophrenia

BACKGROUND

There is a growing interest in the role of immune and inflammatory responses in mental disorders (MDs). Mean platelet volume (MPV) is an extensively utilized hemogram parameter that reflects systemic inflammation and immune function. Our research sought to determine whether a connection exists between MPV and various types of MDs.

METHODS

We searched PubMed, EMBASE, PsychINFO, and Web of Science for eligible studies from inception to 15 February 2023, supplemented by manual searching the references from relevant articles. We applied standardized mean difference (SMD) and its 95% confidence interval (CI) to estimate the differences in MPV values in patients with MDs compared to controls.

RESULTS

We analyzed data from 24 surveys with 4843 participants (2450 patients with MDs and 2393 healthy controls). Two-step meta-analyses were conducted to estimate the SMD in MPV value between individuals with and without MDs. Higher MPV values were substantially linked to MDs (i.e., depression, anxiety, bipolar disorder, and schizophrenia). Moderator and stratified analyses revealed that the aggregate effects were more robust in specific populations, such as younger patients and those who had not taken antipsychotic medication within the previous month.

CONCLUSIONS

Our findings corroborate the role of inflammatory response in the pathogenesis of MDs and the pharmacological treatment of these conditions. Regarding the considerable heterogeneity among studies, the level of evidence was very low to moderate.

Laboratory Markers of Platelet Production and Turnover

Platelets are formed from bone marrow megakaryocytes, circulate in blood for 7-10 days, and then are destroyed in the spleen and/or liver. Platelet production depends on the megakaryocyte population state in the bone marrow: number and size of the cells. The platelet turnover, i.e., the number of platelets passing through the bloodstream in a certain time, is determined by both the rate of their production and the rate of their destruction. The review considers laboratory markers, which are used to assess platelet production and turnover in the patients with hematologic and cardiovascular pathologies. These markers include some characteristics of platelets themselves: (i) content of reticulated ("young") forms in the blood detected by their staining with RNA dyes; (ii) indicators of the platelet size determined in hematology analyzers (mean volume, percentage of large forms) and in flow cytometers (light scattering level). Alterations of platelet production and turnover lead to the changes in blood plasma concentrations of such molecules as thrombopoietin (TPO, main mediator of megakaryocyte maturation and platelet formation in the bone marrow) and glycocalicin (soluble fragment of the membrane glycoprotein Ib detached from the surface of platelets during their destruction). Specific changes in the markers of platelet production and turnover have been observed in: (i) hypoproductive thrombocytopenias caused by suppression of megakaryocytes in the bone marrow; (ii) immune thrombocytopenias caused by accelerated clearance of the autoantibody-sensitized platelets; and (iii) thrombocytosis (both primary and reactive). The paper presents the data indicating that in patients with cardiovascular diseases an increased platelet turnover and changes in the corresponding markers (platelet size indexes and content of reticulated forms) are associated with the decreased efficacy of antiplatelet drugs and increased risk of thrombotic events, myocardial infarction, and unstable angina (acute coronary syndrome).

The Association between Platelet Glycocalicin and High Microsatellite Instability in Colorectal Cancer

Background. Elevated platelet volume is the risk factor for the development and poor overall survival of colorectal cancer (CRC) patients. Both microsatellite status and platelet glycoprotein Ibα (GPIbα) are related to platelet volume in CRC patients. This study aimed to investigate platelet GPIbα ectodomain (termed glycocalicin) levels among CRC patients and the association between the glycocalicin levels and microsatellite status in CRC. Methods. The clinical and laboratory data of 430 CRC patients between January 2018 and December 2018 in Harbin Medical University Cancer Hospital were collected. The microsatellite status was determined with a polymerase chain reaction. The participants were separated into high microsatellite instability (MSI-H) and microsatellite stable (MSS) groups according to microsatellite status. The glycocalicin levels were measured with an enzyme-linked immunosorbent assay, and the cut-off point was determined with the receiver-operating characteristics curve. The clinical and pathological characteristics were collected via electronic medical records. Logistic regression was used to explore the association between glycocalicin and microsatellite status. Results. Among the 430 CRC patients enrolled, 64 patients (14.9%) were identified as MSI-H and others as MSS CRC. Glycocalicin levels were significantly reduced in patients with MSI-H than those with MSS. After controlling for potential confounders, logistic regression analysis revealed that glycocalicin levels were independently associated with MSI-H CRC. Conclusions. Reduced glycocalicin levels are associated with the MSI-H subtype of CRC. Further research is needed to elucidate the mechanisms of the association between glycocalicin and MSI-H in CRC patients.

Platelets as messengers of early-stage cancer

Platelets have an important role in tumor angiogenesis, growth, and metastasis. The reciprocal interaction between cancer and platelets results in changes of several platelet characteristics. It is becoming clear that analysis of these platelet features could offer a new strategy in the search for biomarkers of cancer. Here, we review the human studies in which platelet characteristics (e.g., count, volume, protein, and mRNA content) are investigated in early-stage cancer. The main focus of this paper is to evaluate which platelet features are suitable for the development of a blood test that could detect cancer in its early stages.

Platelet reticulated forms, size indexes, and functional activity. Interactions in healthy volunteers

Reticulated platelets (RP) are young, functionally active platelet forms which are detected by RNA staining. Their content in the circulation reflects the intensity of bone marrow thrombocytopoesis. The aim of this study was to assess in healthy volunteers the relationship between RP percentage and platelet size and activity. RP were quantitated by thiazole orange staining using flow cytometry. Platelet size indexes included mean platelet volume (MPV), platelet large cell ratio (P-LCR) measured in a Coulter type hematological analyzer and forward scattering (FSC) measured in a flow cytometer. Platelet functional activity was evaluated by expression of activated glycoprotein (GP) IIb-IIIa (PAC-1 antibody binding) and P-selectin with the use of flow cytometry. Platelets were activated by thrombin receptor activating peptide (TRAP) (10 and 1 µM) and ADP (20 and 2.5 µM). The percentage of RP in healthy volunteers varied from 2.9% to 23.8% (mean ± SD ‒ 11.7 ± 4.7%, n = 99) and correlated with all platelet size indexes: MPV, P-LCR and FCS (r from 0.452 to 0.529, p < .001, n = 87-99). On average, RP were distributed at a ratio of 9:1 between 50% subpopulations of large and small platelets according to their FSC index. Expression of GP IIb-IIIa activated form correlated with RP percentage and platelet size indexes when platelets were activated by TRAP and ADP at both applied concentrations (r from 0.309 to 0.560, p from 0.014 to < 0.001, n = 50-62). P-selectin expression correlated with RP percentage and platelet size indexes when platelets were activated by 10 µM TRAP inducing maximum expression of this activation marker (r from 0.332 to 0.556, p from 0.008 to < 0.001, n = 65), but not by weaker agonists: 1 µM TRAP, 20 and 2.5 µM ADP (r < 0.3, n = 54-66). Thus, high RP content in healthy volunteers is associated with increased platelet size and activity in the whole platelet population.

Early administration of tirofiban after urokinase-mediated intravenous thrombolysis reduces early neurological deterioration in patients with branch atheromatous disease

Objectives

To investigate the effects of early administration of tirofiban after intravenous thrombolysis on early neurological deterioration in patients with branch atheromatous disease.

Methods

We analyzed clinical data from patients with branch atheromatous disease. We enrolled seven cases into the urokinase-only (UO) control group and 10 cases into the urokinase + tirofiban (UT) treatment group. National Institutes of Health Stroke Scale (NIHSS) scores were obtained at admission and on days 3 and 5 after admission. Modified Rankin Scale (mRS) scores were obtained 3 months after admission.

Results

Significant differences between the UO and UT groups were evident on days 3 and 5 after admission. In the UT group, there was a significant difference between NIHSS scores at admission and on day 5, while there were no significant differences in scores in the UO group. The early neurological deterioration rates were not significantly different between the two groups. However, there were significant differences in these rates at 72 and 120 hours. Both the mRS scores and the prognoses at 3 months differed between the two groups.

Conclusion

Early administration of tirofiban after urokinase-mediated intravenous thrombolysis reduces early neurological deterioration and improves the long-term prognosis of patients with branch atheromatous disease.

Mean Platelet Volume Is Associated with Early Neurological Deterioration in Patients with Branch Atheromatous Disease: Involvement of Platelet Activation

BACKGROUND

The most attentive clinical problem in patients with branch atheromatous disease (BAD) is early neurological deterioration (END). Although the platelet activation (PA) is involved in pathogenesis, the relationship between PA and END has remained unclear. We investigated clinical data including mean platelet volume (MPV, fL) as a marker for PA to identify clinically useful biomarkers for END.

METHODS

A total of 64 patients with BAD were investigated retrospectively, and divided into 2 groups based on whether neurologic symptoms deteriorated or not: BAD with and without END (END and non-END). The END was defined as patients with point increase of 1 or greater in the National Institutes of Health Stroke Scale (NIHSS); non-END was defined as those without such increase. Clinical features such as NIHSS, modified Rankin scale (mRS), laboratory data including MPV, lesion size (LS, mm) on admission, and treatments were compared between the 2 groups.

RESULTS

Of 64 patients, 17 cases had an END. The median values of NIHSS, mRS, MPV, and LS on admission were significantly greater in END than in non-END (P < .05, respectively). There was no correlation of MPV with NIHSS, mRS and LS, respectively. The median values of MPV were significantly higher in END than in non-END and control (P < .05, respectively). A receiver operating characteristic curve indicated a value of 10.1 as cutoff level for MPV to discriminate between END and non-END.

CONCLUSIONS

High MPV values on admission may be an independent biomarker for END. Physicians should pay more careful attention to END in BAD showing MPV values higher than 10.1 on admission.

Platelet genomics: the role of platelet size and number in health and disease

Taken together, there is ample evidence of the association of cardiovascular disease, cerebrovascular, and inflammatory disease with single nucleotide variants (SNV) due to their impact on platelet size, number, and function. With the use of electronic medical record (EMR) or other phenotypic-linked bioinformatics sources, the more important "functional" variants are emerging and provide valuable information on their specific role in promoting early onset of disease or poor response to therapeutic measures. This review will focus upon the recognized common polymorphisms or gene variants with small, but functional effects, as it is becoming clear that these contribute to hyper- or hypo-responsive platelet phenotypes. The impact of these gene variants is distinguishable among normal individuals, and they are suspected contributors to increased risk of adverse outcomes in patients with underlying disease. There are thousands of gene variants and environmental factors that may mitigate risk or amplify the potential for disease within each of us. When combined with the environment and epigenetic influences, it is clear that whole-genome sequencing and bioinformatics alone will not be enough to truly predict "risk" or probability, but awareness of their potential influence may be a starting point in selective screening and generating prevention strategies to promote a healthy lifestyle or fine-tune therapeutic choices in the future.

[The molecular mechanisms of platelets activation in patients with cerebrovascular disease]

Cerebrovascular disease is a main cause of mortality and one of the big medical problems. After the vascular wall's damage the endothelial cells secrete the von Willebrand factor which then connects with its platelet's receptor GP Ib-V-IX. There are two polymorphisms Thr145Met and T(-5)C of the GP Iba gene associated with arterial thrombosis development. Also the difference in platelets' genes expressions was shown in patients with various clinical course of ischemic heart disease. The aim of this study was to investigate the role of platelet's receptor for von Willebrand factor in platelets' activation in patients with cerebrovascular disease. 123 patients with cerebrovascular disease and 97 healthy donors were included into the study. We analyzed the level of receptor for von Willebrand factor on platelet's membrane by flow cytometry, Thr145Met and T(-5)C GP Iba polymorphiams by PCR-RFLP, the GP Iba gene expression by RT-PCR and ADP-induced platelet aggregation by Born method. We have shown: 1) the 145Met GP Iba allele prevalence in patients with atherotrombotic stroke development due to macroangiopathy; 2) the pre-mRNA transform into the mature mRNA in activated platelets and this process may be stopped by the antiplatelet therapy by acetylsalicylic acid.

Gene mutations of platelet glycoproteins and response to tirofiban in acute coronary syndrome

CONTEXT AND OBJECTIVES

Glycoprotein inhibitors (abciximab, eptifibatide and tirofiban) are used in patients with unstable angina and non-ST-segment elevation myocardial infarction before percutaneous coronary intervention. Of these, tirofiban is the least effective. We hypothesized that the response to tirofiban might be associated with glycoprotein gene mutations.

DESIGN AND SETTING

Prospective study at Emergency Unit, Heart Institute (InCor), University of São Paulo.

METHOD

Intrahospital evolution and platelet aggregation in response to tirofiban were analyzed in relation to four glycoprotein mutations in 50 patients indicated for percutaneous coronary intervention: 17 (34%) with unstable angina and 33 (66%) with non-ST-segment elevation myocardial infarction. Platelet aggregation was analyzed using the Born method. Blood samples were obtained before and one hour after tirofiban infusion. Glycoproteins Ia (807C/T ), Ib (Thr/Met) , IIb (Ile/Ser ) and IIIa (PIA ) were the mutations selected.

RESULTS

Hypertension, dyslipidemia, diabetes, smoking, previous coronary artery disease and stroke were similar between the groups. Mutant glycoprotein IIIa genotypes had lower platelet aggregation before tirofiban administration than that of the wild genotype (41.0% ± 22.1% versus 55.9% ± 20.8%; P = 0.035). Mutant glycoprotein IIIa genotypes correlated moderately with lower platelet inhibition (r = -0.31; P = 0.030). After tirofiban administration, platelet glycoprotein Ia, Ib, IIb and IIIa mutations did not influence the degree of inhibition of platelet aggregation or intrahospital mortality.

CONCLUSIONS

Mutations of glycoproteins Ia, Ib, IIb and IIIa did not influence platelet aggregation in response to tirofiban in patients with unstable angina and non-ST-segment elevation myocardial infarction.

Impact of platelet phenotype on myocardial infarction

In acute myocardial infarction patients the injured vascular wall triggers thrombus formation in the damage site. Fibrin fibers and blood cellular elements are the major components of thrombus formed in acute occlusion of coronary arteries. It has been established that the initial thrombus is primarily composed of activated platelets rapidly stabilized by fibrin fibers. This review highlights the role of platelet membrane phenotype in pathophysiology of myocardial infarction. Here, we regard platelet phenotype as quantitative and qualitative parameters of the plasma membrane outer surface, which are crucial for platelet participation in blood coagulation, development of local inflammation and tissue repair.