The role of platelets and platelet inhibition in acute myocardial infarction

Mean platelet volume is associated with serum 25-hydroxyvitamin D concentrations in patients with stable coronary artery disease

There is little published data on the association of platelet function and 25(OH)D concentration. We investigated the associations between mean platelet volume (MPV) and 25(OH)D concentration in patients with stable coronary artery disease. Study population was divided into three groups: group 1-25(OH)D < 10 ng/mL (N = 22), group 2-25(OH)D 10-20 ng/mL (N = 42), and group 3-25(OH)D > 20 ng/mL (N = 14). Study groups shared similar demographics. MPV values were the highest in group 1, moderate in group 2, and the lowest in group 3 (11.1 vs 10.4 vs 9.8 fL P < 0.001). There was a negative correlation between MPV and 25(OH)D (R = - 0.38, P = 0.001). ROC analysis demonstrated a moderate predictive value (AUC 0.70) in identifying the discrimination thresholds of MPV (> 10.5 fL) for vitamin D deficiency and a weak predictive value (AUC 0.65) in identifying the discrimination thresholds of 25(OH)D concentration (≤ 15.5 ng/mL) for the presence of large platelets (MPV over the upper limit of normal). In conclusion, even though the effect of vitamin D on platelet size and function is probably multifactorial, our study provides further evidence linking vitamin D to thrombosis and hemostasis. Platelets are another potential element through which vitamin D deficiency could exert adverse cardiovascular outcomes.

Association between multimorbidity and mean platelet volume in diabetic patients with acute myocardial infarction

AIMS

Diabetes mellitus (DM) is one of the most frequently detected conditions in multimorbid disease clusters. Platelet activation is one of the key mechanisms underlying atherothrombosis in acute myocardial infarction. Available data link mean platelet volume (MPV) to poor prognosis not only in cardiovascular and non-cardiovascular disease. Given the lack of research data on the association between disease clusters and MPV, we have set out to investigate the link between multimorbidity and MPV in diabetic patients with acute myocardial infarction.

METHODS

A total of 277 patients with DM and STEMI undergoing primary percutaneous coronary intervention were enrolled. Based on the number of comorbidities the study population was divided into two groups: group 1 (N = 58) with ≤ 1 comorbidity and group 2 (N = 219) with ≥ 2 comorbidities. A subanalysis was performed within the multimorbidity group: group 2A with two or three comorbidities (N = 156) and group 2B with at least four comorbidities (N = 63).

RESULTS

In the study population, 15.9% of patients had one comorbidity, and 22.0, 34.3, and 22.7% of patients had two, three, or at least four comorbid conditions, respectively. Both MPV and PDW were elevated in multimorbid patients (9.3 vs 10.8 fl and 9.5 vs 10.3 fl, respectively). The highest platelet volume indices were observed in patients with at least four comorbid conditions. There was a moderate positive correlation between MPV and the total number of comorbidities, the number of CVD comorbidities, and the number of non-CVD comorbidities.

CONCLUSIONS

These findings indicate that multimorbidity is associated with an increase in platelet volume indices. MPV values increased with the increasing number of comorbid conditions. Importantly, MPV values were elevated in some, but not all CVD and non-CVD conditions.

Similar Impact of Clopidogrel or Ticagrelor on Carotid Atherosclerotic Plaque Inflammation

BACKGROUND

Platelets play an important role in inflammation. Inhibitors of the P2Y₁₂ receptor, which is involved in platelet activation, may have a direct effect on carotid atherosclerotic plaque inflammation.

HYPOTHESIS

We compared the effects of clopidogrel and ticagrelor therapy for carotid atherosclerotic plaque inflammation using ¹⁸ F-fluorodeoxyglucose ( ¹⁸ FDG) positron emission tomography (PET) imaging.

METHODS

Fifty patients with acute coronary syndrome and ≥1 ¹⁸ FDG uptake in the carotid artery (target-to-background ratio [TBR] ≥1.6) were randomized to either clopidogrel or ticagrelor groups. Of these, 46 completed PET examinations at baseline and at 6 months. The primary endpoint was the percent change in TBR of the index vessel at the most diseased segment (MDS).

RESULTS

Baseline characteristics were similar between the 2 groups. At 6-month follow-up, low-density lipoprotein cholesterol and C-reactive protein significantly decreased in both groups (P < 0.001). The TBR of the index vessel and aorta significantly decreased in both groups (P < 0.01). The percent change in the MDS TBR of the index vessel was numerically but not significantly lower in the clopidogrel group than in the ticagrelor group (-9.5 ± 14.6% vs -13.5 ± 19.3%; P = 0.427). Likewise, the percent change in the whole-vessel TBR of the index vessel was not different between the 2 groups (P = 0.166). Similar findings were observed for changes in the MDS TBR (P = 0.412) or whole-vessel TBR of the aorta (P = 0.363).

CONCLUSIONS

Carotid atherosclerotic plaque inflammation significantly decreases to a similar degree following 6 months of either clopidogrel or ticagrelor treatment.

The change of serum leptin and its relationship with platelet membrane glycoprotein Ib in patients with coronary heart disease

The aim of this paper was to investigate the change of serum leptin and its relationship with platelet membrane glycoprotein Ib (GP Ib) in patients with coronary heart disease (CHD). The enrolled included 50 patients with CHD (CHD group) and 30 patients without CHD (control group) who were diagnosed by coronary angiography. The positive percentage and the average fluorescence intensity of platelet membrane GP Ib were detected by full-blood flow cytometry. Serum leptin was detected by enzyme linked immunosorbent assay. The positive percentage and the average fluorescence intensity of platelet membrane GP Ib in the CHD group were significantly lower than those in the control group (P < 0.05). After correcting the differences of systolic blood pressure, body mass index (BMI), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), fasting glucose, PPBS, fasting insulin and quantitative insulin sensitive index, serum leptin level in the CHD group was significantly higher than that in the control group (P < 0.05). Single factor correlative analysis revealed that serum leptin in CHD patients was negatively correlated with the average fluorescence intensity of platelet membrane GP Ib (P < 0.05). Multifactorial stepwise regression analysis showed that serum leptin in CHD patients was independently negatively correlated with the average fluorescence intensity of platelet membrane GP Ib (P < 0.05). Logistic analysis demonstrated that serum leptin was independently correlated with the risk of CHD (P < 0.05). Hyperleptinemia was verified in CHD patients. The increase of serum leptin could affect blood platelet activation. Hyperleptinemia may play an important role in the pathogenesis of CHD.

Therapeutic Potentials of Sarpogrelate in Cardiovascular Disease*

In view of the pivotal role of serotonin (5-HT) in a wide variety of cardiovascular disorders, extensive effort has been made to develop different types of 5-HT receptor antagonists for therapeutic use. On the basis of experimental studies, this article is focused on the potentials of sarpogrelate, a specific 5-HT2A receptor antagonist as an antiplatelet, antithrombotic, antiatherosclerotic and antianginal agent. The major effects of sarpogrelate are due to the inhibition of 5-HT-induced platelet aggregation and smooth muscle cell proliferation. This agent was found to attenuate the 5-HT-mediated increase in intracellular Ca2+ and ischemia-reperfusion injury in the heart. Sarpogrelate has been found to have beneficial effects in peripheral vascular disease, restenosis after coronary stenting, pulmonary hypertension, acute and chronic myocardial infarction.