The rs3768777-G allele of ITGAV gene is associated with rheumatoid arthritis.

Integrin αvß3 (vitronectin receptor) plays a prominent role in angiogenesis, a key pathogenic feature of rheumatoid arthritis (RA). Moreover, integrin αV (ITGAV) subunit gene has been associated with a susceptibility to RA. The aim of the present study was to detect the potential association between ITGAV gene polymorphisms and a susceptibility to RA in a Turkish cohort. DNA samples were harvested from 160 patients with RA and 144 healthy controls (HC). Three single-nucleotide polymorphisms of ITGAV gene (rs3738919, rs3768777, and rs10174098) were genotyped using real-time PCR. Serum vitronectin levels were analyzed in 30 RA patients, 28 Behçet's disease (BD) patients, and 30 HC subjects. There was no significant difference between the RA and HC groups in terms of the genotypic and allelic distributions of rs3738919 and rs10174098 polymorphisms. However, the prevalence of rs3768777-G allele was higher in the RA group than in the HC group (OR 2.3, 95 % CI 1.6-3.2, p < 0.0001). Moreover, there was a significant association between RA and the genotypic distribution of rs3768777 (GG + AG vs. AA: OR 2.1, 95 % CI 1.3-3.4; GG vs. AG + AA: OR 4.1, 95 % CI 2.1-7.8). Serum vitronectin levels were lower in the RA and BD groups than in the HC group (p ANOVA = 0.002). The rs3738919 and rs10174098 polymorphisms of the ITGAV gene seem not to be associated with susceptibility to RA in Turkish patients. However, rs3768777 increases the risk of RA in this group. These results suggest that the ITGAV gene may be a candidate gene for the etiopathogenesis of RA.

Unexplained pregnancy loss: a marker of basal endothelial dysfunction?

OBJECTIVE: To compare the microparticle levels of women referred for unexplained pregnancy loss with those of parous controls. DESIGN: Incident case-control study. SETTING: University medical center. PATIENT(S): 124 women consecutively referred for unexplained pregnancy losses (two or more losses at or before 21 weeks of gestational age, or at least one later loss), and 273 parous women without pregnancy loss. INTERVENTION(S): Numeration of circulating microparticles by flow cytometry after differentiation of subpopulations according to the expression of membrane-specific antigens (CD51, CD144, or CD146 for endothelial, CD41 for platelet, CD45 and CD66b for leukocyte and neutrophil microparticles). MAIN OUTCOME MEASURE(S): Plasma levels of microparticles. RESULTS: A relative hypercoagulable state assessed by thrombin generation test had been previously reported in such cases, so we hypothesized that this could be explained by an excess of procoagulant microparticles. The study women displayed statistically significantly lower platelet and higher endothelial microparticle levels than the controls. The parameters of the thrombin generation test were only correlated with the level of endothelial microparticles, with a low coefficient of Speerman's correlation (r=0.15). CONCLUSION(S): The difference in microparticle levels between the patients and controls does not clearly explain the hypercoagulable state reported in the patients but could reflect chronic endothelium damage.

[Relationship between alterations of circulating cell-derived microparticles and glucocorticosteroid application].

OBJECTIVE: To explore the relationship between the alterations of circulating cell-derived microparticles (MPs) and large-dose glucocorticosteroid application. METHODS: Peripheral blood samples were collected from 33 patients with history of large-dose glucocorticosteroid application (glucocorticosteroid group) and 24 age-, sex-, and race-matched healthy controls (healthy control group). Platelet-poor plasma was obtained by centrifugation. Plasma microparticles were labeled with monoclonal antibodies of PE-conjugated mouse anti-human CD31, CD54, and FITC-conjugated mouse anti-human CD42b, CD45, CD51/61, CD105, and PE-Cy5-conjugated mouse anti-human CD62E. Cell-derived microparticles were measured by three-color flow cytometry. RESULTS: The mean ranks of CD31+ MPs, CD45+ MPs, CD51/61 MPs, CD31+ CD42b+ MPs, and CD31+ CD45+ MPs of the glucocorticosteroid group were: 24.1, 25.5, 25.6, 21.6, and 24.8 respectively, all significantly lower than those of the control group (35.7, 33.8, 33.7, 39.3, and 34.8 respectively, P = 0.009, 0.019, 0.045, 0.000, and 0.009). CONCLUSION: High-dose glucocorticosteroid application remarkably reduces plasma MPs that may be responsible for microcirculation disturbance.

Circulating endothelial microparticles in patients with acute myocardial infarction.

BACKGROUND: Circulating endothelial microparticles (EMPs), the small vesicles released from altered endothelial cells, have been established as markers of endothelial injury. The elevated count of EMPs has been described in different conditions involving endothelial injury, including acute myocardial infarction (AMI). AIM: To assess the presence of EMP in patients with acute MI in relation to early clinical outcome and coronary angiography results. MATERIALS AND METHODS: EMPs counts were determined in 66 patients pts (23 women, 43 men) with documented ST elevation AMI and in 10 control patients with no evidence of coronary artery disease. All pts with AMI underwent coronary angiography with attempted primary angioplasty. EMPs were assayed by flow cytometry in platelet-poor plasma with combinations of fluorescent antibodies (anti CD31, -51, -42) allowing distinction of EMPs from platelet microparticles. Clinical and angiography results were compared with EMP levels. RESULTS: Three kinds of EMPs were measured: CD31+, CD51+ and CD31+/51+. The percentage of EMPs CD31+/CD51 was significantly (p=0,042) higher in patients with AMI in comparison with control subjects. However, a marker, which distinguished both groups the most, was the level of EMPs CD51+. It was significantly (p=0,024) higher in pts with AMI than in control pts. The levels of CD31+ were similar in both groups. There was no correlation between EMP levels, clinical and angiography results. CONCLUSION: The presence of circulating EMPs provides direct evidence of endothelial injury in AMI. The clinical and practical value of these results, however, needs further exploration.

High levels of circulating endothelial microparticles in patients with acute coronary syndromes.

BACKGROUND: Endothelial injury plays a critical role in coronary artery disease (CAD), but the assessment of this injury has been problematical. Recently, it has been shown in vitro that endothelial cells (ECs) release endothelial microparticles (EMPs) on activation or apoptosis and that an assay of EMPs can provide useful information on EC status in patients with thrombotic disorders. This study is aimed at assessing possible correlations between EMPs, which are markers of endothelial injury, and clinical subgroups of patients with CAD. METHODS: A prospective, case-controlled study was conducted on 84 patients with CAD and 42 control subjects to investigate EMP profiles. Included were 64 patients with acute coronary syndromes ([ACS], 38 with myocardial infarction [MI] and 26 with unstable angina [UA]) and 20 patients with stable angina (SA). EMPs in platelet-poor plasma were measured flow cytometrically with combinations of fluorescent antibodies (anti-CD31, -51, -42), allowing distinction of EMPs from platelet microparticles (PMPs). Clinical subgroups of patients were correlated with EMP and PMP levels in blood. RESULTS: Two species of EMPs (CD31+ and CD51+) were evaluated. Both were significantly higher in patients with CAD than in control subjects. CD31+ EMP was higher in ACS than SA. Among patients with first MI, CD31+ EMP was higher in patients with MI than in patients with UA and was significantly higher than in patients with recurring MI. CD51+ EMP did not discriminate ACS from SA. A simultaneous assay of PMP showed correlation between EMPs and PMPs. However, PMPs did not discriminate patients with SA from control subjects. CONCLUSIONS: EMP assay appears promising for assessing EC injury in CAD.

Effect of a single dose aspirin on platelets in humans with multiple risk factors for coronary artery disease.

We sought to assess how one tablet of non-enteric coated aspirin (325 mg) affects human platelets in subjects with risk factors for coronary artery disease. Data from 63 individuals with multiple cardiac risk factors were analyzed. Platelets were assessed twice at baseline (pre-aspirin), and after 3-4 h (post-aspirin). We employed 5 microM epinephrine-induced conventional aggregometry, closure time with epinephrine/collagen cartridge by PFA-100(R) (Dade-Behring), and aspirin response units (ARU) stimulated by propyl gallat with Ultegra (Accumetrics, San Diego, CA, USA) for measuring platelet function. In addition, the expression of platelet receptors was determined by using the following monoclonal antibodies: anti-CD31, CD41, CD42b, CD51/CD61, CD62p, CD63, CD107a, and CD151. Platelet-leukocyte formation was detected utilizing dual antibodies for a pan-platelet marker CD151, and CD14, a monocyte/macrophage marker. PAC-1 was used to measure fibrinogen-platelet binding. One pill of aspirin significantly decreased platelet-rich plasma (PRP) aggregation (74.18+/-16.75% vs. 24.92+/-8.64%; p<0.0001) and resulted in reduction of the aspirin response units (ARU) (662.24+/-65.65 vs. 451.05+/-69.31; p<0.0001). There was also prolongation of the closure time (194.4+/-25.3 vs. 258.63+/-55.61 s; p<0.0001). High correlation (r(2)=0.73-0.86) between platelet analyzer readings and aggregation was observed. One tablet of aspirin moderately inhibited expression of most surface platelet receptors measured, and such inhibition reached significance (p<0.05) for PAC-1, CD31, CD41, CD42, CD62p, and CD151. We conclude that a single dose of aspirin affects major platelet receptors, presumably directly or indirectly through the inhibition of prostanoids via platelet cyclooxygenase-1 blockade. The Ultegra Analyzer with a novel cartridge seems to be reliable in reflecting aspirins' effects on platelets and could be used in the future in clinical practice for monitoring aspirin therapy.