Variation in platelet expression of FcγRIIa after myocardial infarction

Platelet FcγRIIA: An emerging regulator and biomarker in cardiovascular disease and cancer

Platelets, anucleate blood cells derive from megakaryocytes, are involved in cardiovascular diseases and tumors. FcγRIIA, the only FcγR expressed on human platelets, is known for its role in immune-related diseases. A growing body of evidence reveals that platelet FcγRIIA is a potential target for the prevention and control of cardiovascular disease and cancer, and is an advantageous biomarker. In this review, we describe the structure and physiological function of platelet FcγRIIA, its regulatory role in cardiovascular disease and cancer, and its potential clinical application.

Exploring the potential cost-effectiveness of a novel platelet assay for guiding dual antiplatelet therapy duration in acute coronary syndrome patients following percutaneous coronary intervention

OBJECTIVE

Duration of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) influences ischemic and bleeding events. Platelet expression of constant fragment of immunoglobulin, low affinity IIa, receptor (FcγRIIa) independently predicts risk of ischemic complications and is proposed as a tool to guide individualized care.

METHODS

We used a Markov model to predict lifetime ischemic and bleeding events and healthcare costs in acute myocardial infarction (MI) patients treated with PCI and DAPT and to project cost-effectiveness of platelet FcγRIIa-assay-guided care (30:3 months DAPT for patients at high: low ischemic risk) versus current standard care (12 months DAPT) from the perspective of the US healthcare system. Model inputs included assay sensitivity and specificity, ischemic and bleeding event rates, and impacts on quality of life, mortality, and costs. Assay cost was $90. Sensitivity analyses were conducted over a range of plausible clinical and cost assumptions.

RESULTS

Under base case assumptions, platelet FcγRIIa-assay-guided DAPT duration was projected to increase lifetime costs by $19 versus standard care, with an associated incremental cost-effectiveness ratio (ICER) of $436 per quality-adjusted life-year (QALY) gained. Assay-guided DAPT duration was consistent with high-value care (ICER < $50 000/QALY gained) over a broad range of alternative assumptions.

CONCLUSION

Based on a decision-analytic model, for patients with MI treated with PCI, the additional costs of the platelet FcγRIIa assay for guiding DAPT duration would be largely offset by reductions in downstream event-related costs, and assay-guided care would be highly cost-effective by current standards. These findings require confirmation in prospective studies and in a randomized clinical trial of assay-guided versus nonassay-guided DAPT duration.

Bioinformatics study on different gene expression profiles of fibroblasts and vascular endothelial cells in keloids

Keloid is a benign fibroproliferative skin tumor. The respective functions of fibroblasts and vascular endothelial cells in keloid have not been fully studied. The purpose of this study is to identify the respective roles and key genes of fibroblasts and vascular endothelial cells in keloids, which can be used as new targets for diagnosis or treatment.The microarray datasets of keloid fibroblasts and vascular endothelial cells were obtained from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were screened out. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used for functional enrichment analysis. The search tool for retrieval of interacting genes and Cytoscape were used to construct protein-protein interaction (PPI) networks and analyze gene modules. The hub genes were screened out, and the relevant interaction networks and biological process analysis were carried out.In fibroblasts, the DEGs were significantly enriched in collagen fibril organization, extracellular matrix organization and ECM-receptor interaction. The PPI network was constructed, and the most significant module was selected, which is mainly enriched in ECM-receptor interaction. In vascular endothelial cells, the DEGs were significantly enriched in cytokine activity, growth factor activity and transforming growth factor-β (TGF-β) signaling pathway. Module analysis was mainly enriched in TGF-β signaling pathway. Hub genes were screened out separately.In summary, the DEGs and hub genes discovered in this study may help us understand the molecular mechanisms of keloid, and provide potential targets for diagnosis and treatment.

FCGR2A Could Function as a Prognostic Marker and Correlate with Immune Infiltration in Head and Neck Squamous Cell Carcinoma

Objective

We aim to investigate the correlation between FCGR2A mRNA level and prognosis of head and neck squamous cancer (HNSC) in public databases. In addition, we investigated the correlation between FCGR2A expression and clinicopathological characteristics and tumor-infiltrating immune cells in HNSC patients.

Methods

FCGR2A mRNA expression in multiple cancers was analyzed based on Gene Expression Profiling Interactive Analysis. A protein-protein interaction network was obtained based on the STRING database. The 10 proteins most closely related to FCGR2A (i.e., CD3G, PLCG2, LAT, LYN, SYK, FCGR3A, PIK3R1, HCK, ITGAM, and ITGB2) were screened, followed by establishing the protein-protein interaction network. The correlation between FCGR2A expression and immunocytes was investigated, together with the effects of FCGR2A on the metastasis, recurrence, and survival of HNSC.

Results

FCGR2A expression in several carcinoma tissues was significantly higher than that of adjacent tissues. Significant differences were noticed in the HNSC samples and the adjacent tissue samples except the seven samples of grade 4. There were statistical differences between the FCGR2A expression in tissues of grade 1, grade 2, and grade 3 (P < 0.05). In the tissues of grade 4, the expression of FCGR2A was the lowest. The FCGR2A protein was a type of II-a receptor in γFc of the low-affinity immunoglobulin, which could bind with the Fc region of the immunoglobulin γ. There was a correlation between the FCGR2A gene and the distal HNSC metastasis. FCGR2A gene expression was correlated with the survival and prognosis. The GSE65858 dataset was selected for the validation. The FCGR2A expression was significantly correlated with total survival (P = 0.0107) and progression-free survival (P = 0.0362).

Conclusions

Our findings shed light on the importance of FCGR2A in HNSC and illustrated a potential relationship between FCGR2A and tumor-immune interactions.

Endothelial Shear Stress and Platelet FcγRIIa Expression in Intracranial Atherosclerotic Disease

Intracranial atherosclerotic disease (ICAD) has been characterized by the degree of arterial stenosis and downstream hypoperfusion, yet microscopic derangements of endothelial shear stress at the luminal wall may be key determinants of plaque growth, vascular remodeling and thrombosis that culminate in recurrent stroke. Platelet interactions have similarly been a principal focus of treatment, however, the mechanistic basis of anti-platelet strategies is largely extrapolated rather than directly investigated in ICAD. Platelet FcγRIIa expression has been identified as a potent risk factor in cardiovascular disease, as elevated expression markedly increases the risk of recurrent events. Differential activation of the platelet FcγRIIa receptor may also explain the variable response of individual patients to anti-platelet medications. We review existing data on endothelial shear stress and potential interactions with the platelet FcγRIIa receptor that may alter the evolving impact of ICAD, based on local pathophysiology at the site of arterial stenosis. Current methods for quantification of endothelial shear stress and platelet activation are described, including tools that may be readily adapted to the clinical realm for further understanding of ICAD.

Assessment of Cardiovascular Risk by the Combination of Clinical Risk Scores Plus Platelet Expression of FcγRIIa

Platelet expression of FcγRIIa was quantified after myocardial infarction (MI) and we found that patients with high platelet FcγRIIa expression (>11,000/platelet) had a fourfold greater risk of subsequent MI, stroke, and death. This analysis of the original cohort of 197 patients was designed to determine whether platelet expression of FcγRIIa could be used in combination with clinical risk scores (GRACE [Global Registry of Acute Coronary Events] and DAPT [Dual Antiplatelet Therapy]) to refine cardiovascular risk assessment. Platelet expression of FcγRIIa quantified with the use of flow cytometry was broadly distributed in patients stratified into high and low risk groups based on clinical risk scores. In patients identified as high risk by the GRACE score, 62% had high platelet FcγRIIa expression. Similarly, in patients identified as high risk by DAPT, 55% had high platelet FcγRIIa expression. High platelet FcγRIIa expression discriminated high and low risk cohorts in patients with high cardiovascular risk defined by either the GRACE score (high platelet FcγRIIa 18.9% vs low platelet FcγRIIa 0%; odds ratio = 15.7, p = 0.06) or the DAPT score (high platelet FcγRIIa 15.4% vs low platelet FcγRIIa 3.7%; odds ratio = 5.6, p = 0.03) assessment. Platelet expression of FcγRIIa merits additional study to determine whether low platelet FcγRIIa expression can be used to guide early transition to aspirin monotherapy and high platelet FcγRIIa expression can be used to guide continuation of DAPT.