Circulating reticulated platelets over time in patients with myocardial infarction treated with prasugrel or ticagrelor.

Reticulated platelets (RP) are young, hyperactive platelets that are increased during situations of enhanced platelet turnover such as acute myocardial infarction (AMI). The dynamics of RP levels after AMI is not established. We aimed to characterize the levels of circulating RP over time in patients with AMI. Patients with AMI treated with ticagrelor or prasugrel who underwent percutaneous coronary intervention (PCI) were tested for circulating RP using flow cytometry with Thiazole orange staining at 3 time points at 2-4 days, 30-60 days and 1 year post PCI. Platelet reactivity was assessed using the VerifyNow P2Y12 assay at these time points (results in platelet reactivity units-PRU). Thirty-five patients were included in the study (mean age 62.6 ± 9.1 years, 82.9 % males). Median RP levels were similar at the first and second time points (17.5 %, IQR 25-75: 10.8-22.4 % and 14.9 %, IQR 25-75: 9.7-26.8 %, respectively; p = 0.75). However, RP levels after 1 year were significantly lower as compared to the first and second time points (10.5 % (IQR 25-75: 5.3-18.1 %), p = 0.005 and p = 0.01, respectively). Residual platelet reactivity was very low at all 3 time points (median PRU 25, IQR 25-75: 7-53) and did not change significantly between them (p = 0.66). No significant correlation was found between levels of RP and PRU at any given time point. RP levels of patients with AMI treated with prasugrel or ticagrelor decrease over time after the acute event. However, RP levels over time do not correlate well with residual platelet reactivity.

Effect of intensive glycaemic control on endothelial progenitor cells in patients with long-standing uncontrolled type 2 diabetes.

AIMS: Endothelial progenitor cells (EPCs) have an important role in repair following vascular injury. However, in patients with diabetes, EPC number and function are markedly reduced. It is unclear whether intensive glycaemic control can modify EPC properties in diabetic patients. We aimed to examine whether glycaemic control can improve EPC number and function in patients with long-standing uncontrolled type 2 diabetes. METHODS AND RESULTS: Thirty-five patients with treated type 2 diabetes and HgA1c ≥ 8.5% were included. Patients were tested at baseline and after 3-4 months of an intensive glycaemic control programme, with the aim of achieving HgA1c of 7%. The diabetes group was compared to 20 patients without diabetes (control). Circulating EPC levels were assessed by flow cytometry for expression of VEGFR2, CD133, and CD34. The capacity of the cells to form colony-forming units (CFUs), and their migration and viability were quantified after 1 week of culture. Patients with diabetes (mean age 61.1 ± 7 years, 28.6% women, disease duration of 19.2 ± 8 years) had a baseline HgA1c of 9.4 ± 0.8%. After the glycaemic control period, HgA1c decreased to 8 ± 0.8%. Circulating EPC levels increased significantly after the intensive control period and reached a level similar to the control group. The number of EPC CFUs also increased significantly after glycaemic control but remained lower than the control group. All EPC functional assays improved following the glycaemic control. CONCLUSIONS: In patients with uncontrolled long-standing type 2 diabetes, intensive glycaemic control was associated with an increase in the levels of circulating EPCs, and improvement in their functional properties.

Response to prasugrel and levels of circulating reticulated platelets in patients with ST-segment elevation myocardial infarction.

OBJECTIVES: The aim of this study was to determine whether response to prasugrel is associated with the proportion of circulating reticulated platelets (RPs) in patients with ST-segment elevation myocardial infarction (STEMI). BACKGROUND: Despite better pharmacodynamic properties and clinical efficacy of prasugrel compared with clopidogrel, antiplatelet responses to prasugrel are not uniform. The mechanism of this variability in response is not clear. RPs, young hyperactive forms, are increased during situations of enhanced platelet turnover. METHODS: Patients with STEMI treated with primary percutaneous intervention (PCI) and prasugrel were tested for platelet reactivity using purinergic receptor P2Y, G-protein coupled, 12 (P2Y12) assay and multiple electrode aggregometry (MEA). RP levels were determined using flow cytometry with thiazole orange staining. Tests were performed at 2 to 4 days and 30 days post-PCI. Platelet function was compared by varying levels of RPs, analyzed as continuous (regression analysis) and categorical (tertiles) variables. RESULTS: Sixty-two patients were included (mean age: 57.5 ± 8 years; 21.2% women; 27.7% diabetes). At the early time point, RP levels were strongly correlated with platelet reactivity when evaluated by the P2Y12 assay (Spearman's correlation coefficient: 0.55 for P2Y12 reaction units, -0.49 for percent inhibition) and MEA (Spearman's: 0.50). The upper tertile of RPs displayed higher platelet reactivity compared with the middle and lower tertiles, according to P2Y12 assay and MEA. Similar results with strong correlations between RP and platelet reactivity were noted at 30 days post-PCI. CONCLUSIONS: The proportion of circulating RPs strongly correlates with response to prasugrel in patients with STEMI treated with PCI. High levels of RPs are associated with increased platelet reactivity despite prasugrel treatment.

Circulating endothelial progenitor cells in patients with dysfunctional versus normally functioning congenitally bicuspid aortic valves.

Patients with bicuspid aortic valve (BAV) may gradually develop significant valve dysfunction, whereas others remain free of dysfunction. Factors that determine the prognosis of BAV remain unclear. Because endothelial progenitor cells (EPCs) have a role in the repair of endothelial surfaces after injury, we hypothesized that EPCs may also be involved in preventing BAV degeneration. Accordingly, we compared EPC level and function in patients with BAV with versus without valve dysfunction. The study group included 22 patients with BAV and significant valve dysfunction (at least moderate aortic regurgitation and/or at least moderate aortic stenosis). The control group included 28 patients with BAV without valve dysfunction. All patients had 1 blood sample taken. Proportion of peripheral mononuclear cells expressing vascular endothelial growth factor receptor 2, CD133 and CD34 was evaluated by flow cytometry. EPC colony-forming units (CFUs) were grown from peripheral mononuclear cells, characterized, and counted after 7 days of culture. The 2 groups had similar clinical characteristics except for higher prevalence of hypertension in the dysfunctional valve group. Number of EPC CFUs was smaller in the dysfunctional valve group (32 CFUs/plate, 15 to 42.5, vs 48 CFUs/plate, 30 to 62.5, respectively, p = 0.01), and the migratory capacity of the cells in this group was decreased. In addition, the proportion of cells coexpressing vascular endothelial growth factor receptor 2, CD133, and CD34 tended to be smaller in the dysfunctional valve group. In conclusion, patients with BAV and significant valve dysfunction appear to have circulating EPCs with impaired functional properties. These findings require validation by further studies.

The Ras antagonist, farnesylthiosalicylic acid (FTS), decreases fibrosis and improves muscle strength in dy/dy mouse model of muscular dystrophy.

The Ras superfamily of guanosine-triphosphate (GTP)-binding proteins regulates a diverse spectrum of intracellular processes involved in inflammation and fibrosis. Farnesythiosalicylic acid (FTS) is a unique and potent Ras inhibitor which decreased inflammation and fibrosis in experimentally induced liver cirrhosis and ameliorated inflammatory processes in systemic lupus erythematosus, neuritis and nephritis animal models. FTS effect on Ras expression and activity, muscle strength and fibrosis was evaluated in the dy(2J)/dy(2J) mouse model of merosin deficient congenital muscular dystrophy. The dy(2J)/dy(2J) mice had significantly increased RAS expression and activity compared with the wild type mice. FTS treatment significantly decreased RAS expression and activity. In addition, phosphorylation of ERK, a Ras downstream protein, was significantly decreased following FTS treatment in the dy(2J)/dy(2J) mice. Clinically, FTS treated mice showed significant improvement in hind limb muscle strength measured by electronic grip strength meter. Significant reduction of fibrosis was demonstrated in the treated group by quantitative Sirius Red staining and lower muscle collagen content. FTS effect was associated with significantly inhibition of both MMP-2 and MMP-9 activities. We conclude that active RAS inhibition by FTS was associated with attenuated fibrosis and improved muscle strength in the dy(2J)/dy(2J) mouse model of congenital muscular dystrophy.

Improved muscle strength and mobility in the dy(2J)/dy(2J) mouse with merosin deficient congenital muscular dystrophy treated with Glatiramer acetate.

The therapeutic effect of Glatiramer acetate, an immune modulating agent, was evaluated in the dy(2J)/dy(2J) mouse with merosin deficient congenital muscular dystrophy, which is a milder variant of the dy/dy mouse. The treated mice showed significant improvement in hind limb muscle strength measured by electronic grip strength meter and in motor performance quantified by video detection software. Glatiramer acetate treatment was associated with significantly increased expression of regeneration transcription factors MyoD and myogenin, and attenuation of the fibrosis markers vimentin and fibronectin. No effective treatment is currently available in congenital muscular dystrophy and Glatiramer acetate may present a new potential treatment for this disorder.