001 Predictive Value of Post Treatment Platelet Reactivity for Occurrence of Post-discharge Bleeding After Non ST Elevation Acute Coronary Syndrome

AimsWe assessed prospectively the association between occurrence of post-discharge non–CABG-related TIMI major and minor bleedings and post treatment platelet reactivity in patients with Non ST Elevation Acute Coronary Syndrome (NSTE ACS).Methods and Results597 consecutive patients admitted with NSTE ACS were prospectively included. Between hospital discharge and one month follow-up, we observed 16 (2.7%) non–CABG-related TIMI hemorrhagic complications including 5 (0.84%) major and 11 (1.8%) minor bleeds. Patients with bleeding had significantly lower post treatment values of ADP-induced aggregation (43±14% versus. 56±19%, P=0.002) and platelet reactivity index VASP (43±14% versus 54±23%; P=0.04) and a trend for lower values of arachidonic acid-induced aggregation (2.4±5.4 versus 13±21; P=0.27). After stratification by quartiles based on post treatment ADP-induced platelet aggregation, we identified patients in the first quartile as hyper-responders with very low post treatment platelet reactivity, below <40%. The risk of TIMI major and minor bleeding was significantly higher in the first quartile of hyper-responders than in the others quartiles: 10 (6.6%) versus 6 (1.4%), p=0.001.ConclusionOur results suggest that assessment of post treatment platelet reactivity might be used to detect hyper responders to antiplatelet therapy with higher risk of non-CABG related bleedings and tailor antiplatelet therapy according to both ischemic and bleeding risk

Characterization of human mesenchymal stem cell secretome at early steps of adipocyte and osteoblast differentiation

<p>Abstract</p> <p>Background</p> <p>It is well established that adipose tissue plays a key role in energy storage and release but is also a secretory organ and a source of stem cells. Among different lineages, stem cells are able to differentiate into adipocytes and osteoblasts. As secreted proteins could regulate the balance between both lineages, we aimed at characterizing the secretome of human multipotent adipose-derived stem cell (hMADS) at an early step of commitment to adipocytes and osteoblasts.</p> <p>Results</p> <p>A proteomic approach, using mono-dimensional electrophoresis and tandem mass spectrometry, allowed us to identify a total of 73 proteins at day 0 and day 3 of adipocyte and osteoblast differentiation. Analysis of identified proteins showed that 52 % corresponded to classical secreted proteins characterized by a signal peptide, that 37 % previously described in the extracellular compartment were devoid of signal peptide and that 11 % neither exhibited a signal peptide nor had been previously described extracellularly. These proteins were classified into 8 clusters according to their function. Quantitative analysis has been performed for 8 candidates: PAI-1, PEDF, BIGH3, PTX3, SPARC, ENO1, GRP78 and MMP2. Among them, PAI-1 was detected at day 0 and day 3 of osteoblast differentiation but never in adipocyte secretome. Furthermore we showed that PAI-1 mRNA was down-regulated in the bone of ovariectomized mice.</p> <p>Conclusion</p> <p>Given its regulation during the early events of hMADS cell differentiation and its status in ovariectomized mice, PAI-1 could play a role in the adipocyte/osteoblast balance and thus in bone diseases such as osteoporosis.</p

Effects of Bariatric Surgery on Cardiac Ectopic Fat Lesser Decrease in Epicardial Fat Compared to Visceral Fat Loss and No Change in Myocardial Triglyceride Content

ObjectivesThis study investigated the effect of bariatric surgery (BS)–induced weight loss on cardiac ectopic fat using 3T magnetic resonance imaging in morbid obesity.BackgroundHeart disease is one of the leading causes of mortality and morbidity in obese patients. Deposition of cardiac ectopic fat has been related to increased heart risk. Whether sustained weight loss can modulate epicardial fat or myocardial fat is unknown.MethodsTwenty-three morbidly obese patients underwent 1H-magnetic resonance spectroscopy to determine myocardial triglyceride content (MTGC), magnetic resonance imaging to assess epicardial fat volume (EFV), cardiac function, and computed tomography visceral abdominal fat (VAF) measurements at baseline and 6 months after BS.ResultsThe BS reduced body mass index significantly, from 43.1 ± 4.5 kg/m2 to 32.3 ± 4.0 kg/m2, subcutaneous fat from 649 ± 162 cm2 to 442 ± 127 cm2, VAF from 190 ± 83 cm2 to 107 ± 44 cm2, and EFV from 137 ± 37 ml to 98 ± 25 ml (all p < 0.0001). There was no significant change in MTGC: 1.03 ± 0.2% versus 1.1 ± 0.2% (p = 0.85). A significant reduction in left ventricular mass (118 ± 24 g vs. 101 ± 18 g) and cardiac output (7.1 ± 1.6 l/min vs. 5.4 ± 1.0 l/min) was observed and was statistically associated with weight loss (p < 0.05). The loss in EFV was limited (−27 ± 11%) compared to VAF diminution (−40 ± 19%). The EFV variation was not correlated with percentage of body mass index or VAF loss (p = 0.007). The ratio of %EFV to %VAF loss decreased with sleep apnea syndrome (1.34 ± 0.3 vs. 0.52 ± 0.08, p < 0.05).ConclusionsSix-month BS modulates differently cardiac ectopic fat deposition, with a significant decrease in epicardial fat and no change in myocardial fat. Epicardial fat volume loss was limited in patients with sleep apnea. (Impact of Bariatric Surgery on Epicardial Adipose Tissue and on Myocardial Function; NCT01284816

Genetics of venous thrombosis: insights from a new genome wide association study

Background: Venous Thrombosis (VT) is a common multifactorial disease associated with a major public health burden. Genetics factors are known to contribute to the susceptibility of the disease but how many genes are involved and their contribution to VT risk still remain obscure. We aimed to identify genetic variants associated with VT risk. Methodology/Principal Findings: We conducted a genome-wide association study (GWAS) based on 551,141 SNPs genotyped in 1,542 cases and 1,110 controls. Twelve SNPs reached the genome-wide significance level of 2.0×10−8 and encompassed four known VT-associated loci, ABO, F5, F11 and FGG. By means of haplotype analyses, we also provided novel arguments in favor of a role of HIVEP1, PROCR and STAB2, three loci recently hypothesized to participate in the susceptibility to VT. However, no novel VT-associated loci came out of our GWAS. Using a recently proposed statistical methodology, we also showed that common variants could explain about 35% of the genetic variance underlying VT susceptibility among which 3% could be attributable to the main identified VT loci. This analysis additionally suggested that the common variants left to be identified are not uniformly distributed across the genome and that chromosome 20, itself, could contribute to ∼7% of the total genetic variance. Conclusions/Significance: This study might also provide a valuable source of information to expand our understanding of biological mechanisms regulating quantitative biomarkers for VT

A rare coding mutation in the MAST2 gene causes venous thrombosis in a French family with unexplained thrombophilia: The Breizh MAST2 Arg89Gln variant.

Rare variants outside the classical coagulation cascade might cause inherited thrombosis. We aimed to identify the variant(s) causing venous thromboembolism (VTE) in a family with multiple relatives affected with unprovoked VTE and no thrombophilia defects. We identified by whole exome sequencing an extremely rare Arg to Gln variant (Arg89Gln) in the Microtubule Associated Serine/Threonine Kinase 2 (MAST2) gene that segregates with VTE in the family. Free-tissue factor pathway inhibitor (f-TFPI) plasma levels were significantly decreased in affected family members compared to healthy relatives. Conversely, plasminogen activator inhibitor-1 (PAI-1) levels were significantly higher in affected members than in healthy relatives. RNA sequencing analysis of RNA interference experimental data conducted in endothelial cells revealed that, of the 13,387 detected expressed genes, 2,354 have their level of expression modified by MAST2 knockdown, including SERPINE1 coding for PAI-1 and TFPI. In HEK293 cells overexpressing the MAST2 Gln89 variant, TFPI and SERPINE1 promoter activities were respectively lower and higher than in cells overexpressing the MAST2 wild type. This study identifies a novel thrombophilia-causing Arg89Gln variant in the MAST2 gene that is here proposed as a new molecular player in the etiology of VTE by interfering with hemostatic balance of endothelial cells

Exome sequencing identifies NBEAL2 as the causative gene for gray platelet syndrome.

Gray platelet syndrome (GPS) is a predominantly recessive platelet disorder that is characterized by mild thrombocytopenia with large platelets and a paucity of α-granules; these abnormalities cause mostly moderate but in rare cases severe bleeding. We sequenced the exomes of four unrelated individuals and identified NBEAL2 as the causative gene; it has no previously known function but is a member of a gene family that is involved in granule development. Silencing of nbeal2 in zebrafish abrogated thrombocyte formation

Expanded repertoire of RASGRP2 variants responsible for platelet dysfunction and severe bleeding.

Heritable platelet function disorders (PFDs) are genetically heterogeneous and poorly characterized. Pathogenic variants in RASGRP2, which encodes calcium and diacylglycerol-regulated guanine exchange factor I (CalDAG-GEFI), have been reported previously in 3 pedigrees with bleeding and reduced platelet aggregation responses. To better define the phenotype associated with pathogenic RASGRP2 variants, we compared high-throughput sequencing and phenotype data from 2042 cases in pedigrees with unexplained bleeding or platelet disorders to data from 5422 controls. Eleven cases harbored 11 different, previously unreported RASGRP2 variants that were biallelic and likely pathogenic. The variants included 5 high-impact variants predicted to prevent CalDAG-GEFI expression and 6 missense variants affecting the CalDAG-GEFI CDC25 domain, which mediates Rap1 activation during platelet inside-out αIIbβ3 signaling. Cases with biallelic RASGRP2 variants had abnormal mucocutaneous, surgical, and dental bleeding from childhood, requiring ≥1 blood or platelet transfusion in 78% of cases. Platelets displayed reduced aggregation in response to adenosine 5'-diphosphate and epinephrine, but variable aggregation defects with other agonists. There were no other consistent clinical or laboratory features. These data enable definition of human CalDAG-GEFI deficiency as a nonsyndromic, recessive PFD associated with a moderate or severe bleeding phenotype and complex defects in platelet aggregation

Platelets Alter Gene Expression Profile in Human Brain Endothelial Cells in an In Vitro Model of Cerebral Malaria

Platelet adhesion to the brain microvasculature has been associated with cerebral malaria (CM) in humans, suggesting that platelets play a role in the pathogenesis of this syndrome. In vitro co-cultures have shown that platelets can act as a bridge between Plasmodium falciparum-infected red blood cells (pRBC) and human brain microvascular endothelial cells (HBEC) and potentiate HBEC apoptosis. Using cDNA microarray technology, we analyzed transcriptional changes of HBEC in response to platelets in the presence or the absence of tumor necrosis factor (TNF) and pRBC, which have been reported to alter gene expression in endothelial cells. Using a rigorous statistical approach with multiple test corrections, we showed a significant effect of platelets on gene expression in HBEC. We also detected a strong effect of TNF, whereas there was no transcriptional change induced specifically by pRBC. Nevertheless, a global ANOVA and a two-way ANOVA suggested that pRBC acted in interaction with platelets and TNF to alter gene expression in HBEC. The expression of selected genes was validated by RT-qPCR. The analysis of gene functional annotation indicated that platelets induce the expression of genes involved in inflammation and apoptosis, such as genes involved in chemokine-, TREM1-, cytokine-, IL10-, TGFβ-, death-receptor-, and apoptosis-signaling. Overall, our results support the hypothesis that platelets play a pathogenic role in CM