| 1. |
- De Muinck, Ebo D., et al.
(författare)
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Protection against myocardial ischemia-reperfusion injury by the angiogenic masterswitch protein PR 39 gene therapy : the roles of HIF1 alpha stabilization and FGFR1 signaling
- 2007
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Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert. - 1523-0864 .- 1557-7716. ; 9:4, s. 437-445
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Tidskriftsartikel (refereegranskat)abstract
- PR-39, a proline-arginine-rich angiogenic response peptide, has been implicated in myocardial ischemic reperfusion injury. The present study examined the cardioprotective abilities of PR39 gene therapy. Male C5713146 mice were randomized to intramyocardial injecton of 10(9) p.f.u. adenovirus encoding PR39 (PR39), FGFR1 dominant negative signaling construct (FGFR1-dn), empty vector (EV), or PR39 adenovirus plus 4 mu g of plasmid endcoding a HIF1 alpha dominant negative construct (PR39 + HIF1 alpha-dn). Seven days later, hearts were subjected to 20 min of ischemia (1) and 2 h. reperfusion (R) ex vivo and aortic and coronary flow, left ventricular developed pressure (LVDP), and LVdp/dt were measured. Myocardial infarct (MI) size and cardiomyocyte apoptosis were measured by TTC staining and TUNEL, respectively. PR39 expression was robust up to 14 days after gene transfer and was absent after EV and FGFR1-dn. Hemodynamics showed no differences at baseline, and heart rate remained unchanged in all groups throughout the experiment. After I-R, hemodynamics remained unchanged in PR39 hearts, but deteriorated significantly in the other groups, except for aortic flow, which remained significantly higher in FGFR1-dn than in EV and PR39 + HIF1 alpha-dn (p less than 0.05), although it was lower than in PR39 (p less than 0.05). MI was 8.7 +/- 0.9 % in PR39, 23.8 +/- 1.1 % in FGFR1-dn, 29.9 +/- 2.2% in EV, and 30.8 +/- 2.7 % in PR39 + HIF1 alpha-dn (PR39 vs. other groups: p less than 0.05; FGFR1-dn vs. EV and PR39 + HIF1 alpha-dn: p less than 0.05). In PR39, HIF-1 alpha protein was higher than in FGFR1-dn and EV. Importantly, cotransfection of HlF1 alpha-dn with PR39 completely abolished cardioprotection by PR39. Cardioprotection by PR39 is likely conveyed by protective metabolic and survival responses through HIF1-alpha stabilization and not by angiogenesis, because baseline coronary How was the same in all groups. Abrogation of FGFR1 signaling conveyed an intermediate degree of cardioprotection.
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| 2. |
- Vasan, Ramachandran S, et al.
(författare)
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Genetic variants associated with cardiac structure and function : a meta-analysis and replication of genome-wide association data
- 2009
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Ingår i: Journal of the American Medical Association (JAMA). - : American Medical Association (AMA). - 0098-7484 .- 1538-3598. ; 302:2, s. 168-178
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: Echocardiographic measures of left ventricular (LV) structure and function are heritable phenotypes of cardiovascular disease. OBJECTIVE: To identify common genetic variants associated with cardiac structure and function by conducting a meta-analysis of genome-wide association data in 5 population-based cohort studies (stage 1) with replication (stage 2) in 2 other community-based samples. DESIGN, SETTING, AND PARTICIPANTS: Within each of 5 community-based cohorts comprising the EchoGen consortium (stage 1; n = 12 612 individuals of European ancestry; 55% women, aged 26-95 years; examinations between 1978-2008), we estimated the association between approximately 2.5 million single-nucleotide polymorphisms (SNPs; imputed to the HapMap CEU panel) and echocardiographic traits. In stage 2, SNPs significantly associated with traits in stage 1 were tested for association in 2 other cohorts (n = 4094 people of European ancestry). Using a prespecified P value threshold of 5 x 10(-7) to indicate genome-wide significance, we performed an inverse variance-weighted fixed-effects meta-analysis of genome-wide association data from each cohort. MAIN OUTCOME MEASURES: Echocardiographic traits: LV mass, internal dimensions, wall thickness, systolic dysfunction, aortic root, and left atrial size. RESULTS: In stage 1, 16 genetic loci were associated with 5 echocardiographic traits: 1 each with LV internal dimensions and systolic dysfunction, 3 each with LV mass and wall thickness, and 8 with aortic root size. In stage 2, 5 loci replicated (6q22 locus associated with LV diastolic dimensions, explaining <1% of trait variance; 5q23, 12p12, 12q14, and 17p13 associated with aortic root size, explaining 1%-3% of trait variance). CONCLUSIONS: We identified 5 genetic loci harboring common variants that were associated with variation in LV diastolic dimensions and aortic root size, but such findings explained a very small proportion of variance. Further studies are required to replicate these findings, identify the causal variants at or near these loci, characterize their functional significance, and determine whether they are related to overt cardiovascular disease.
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| 3. |
- Greinacher, A, et al.
(författare)
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Heparin-induced thrombocytopenia : a prospective study on the incidence, platelet-activating capacity and clinical significance of antiplatelet factor 4/heparin antibodies of the IgG, IgM, and IgA classes.
- 2007
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Ingår i: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 5:8, s. 1666-73
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Platelet-activating antiplatelet factor 4/heparin (anti-PF4/heparin) antibodies are the major cause of heparin-induced thrombocytopenia (HIT). However, the relative utility of functional (platelet activation) vs. antigen [enzyme-immunoassay (EIA)] assays, and the significance of assay discrepancies remain unresolved. METHODS: Consecutive patient sera (n = 1650) referred for diagnostic HIT testing were screened prospectively by both the heparin-induced platelet activation (HIPA) test and anti-PF4/heparin EIA - including individual classes (IgG, IgA, IgM) - with clinical correlations studied. Platelet microparticle and annexin-V-binding properties of the sera were also investigated. RESULTS: Only 205 (12.4%) sera tested positive in either the HIPA and/or EIA: 95 (46.3%) were positive in both, 109 (53.1%) were only EIA-positive, and, notably, only one serum was HIPA-positive/EIA-negative. Of 185 EIA-positive sera, only 17.6% had detectable IgM and/or IgA without detectable IgG. Among sera positive for EIA IgG, optical density values were higher when the sera were HIPA-positive (1.117 vs. 0.768; P < 0.0001), with widely overlapping values. Two HIPA-positive but EIA-IgG-negative sera became HIPA-negative following IgG depletion, suggesting platelet-activating antibodies against non-PF4-dependent antigens. Clinical correlations showed that HIPA-negative/EIA-positive patients did not develop thrombosis and had reasons other than HIT to explain thrombocytopenia. IgM/A antibodies did not increase microparticle penetration, but increased annexin-V binding. CONCLUSIONS: The anti-PF4/heparin EIA has high ( approximately 99%) sensitivity for HIT. However, only about half of EIA-positive patients are likely to have HIT. Anti-PF4/heparin antibodies of IgM/A class and non-PF4-dependent antigens have only a minor role in HIT.
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| 4. |
- Jallow, Muminatou, et al.
(författare)
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Genome-wide and fine-resolution association analysis of malaria in West Africa.
- 2009
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; , s. 657-665
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Tidskriftsartikel (refereegranskat)abstract
- We report a genome-wide association (GWA) study of severe malaria in The Gambia. The initial GWA scan included 2,500 children genotyped on the Affymetrix 500K GeneChip, and a replication study included 3,400 children. We used this to examine the performance of GWA methods in Africa. We found considerable population stratification, and also that signals of association at known malaria resistance loci were greatly attenuated owing to weak linkage disequilibrium (LD). To investigate possible solutions to the problem of low LD, we focused on the HbS locus, sequencing this region of the genome in 62 Gambian individuals and then using these data to conduct multipoint imputation in the GWA samples. This increased the signal of association, from P = 4 x 10(-7) to P = 4 x 10(-14), with the peak of the signal located precisely at the HbS causal variant. Our findings provide proof of principle that fine-resolution multipoint imputation, based on population-specific sequencing data, can substantially boost authentic GWA signals and enable fine mapping of causal variants in African populations.
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