Mechanisms of Vascular Dysfunction in COPD and Effects of a Novel Soluble Epoxide Hydrolase Inhibitor in Smokers.

BACKGROUND: Smoking and COPD are risk factors for cardiovascular disease, and the pathogenesis may involve endothelial dysfunction. We tested the hypothesis that endothelium-derived epoxyeicosatrienoic acid (EET)-mediated endothelial function is impaired in patients with COPD and that a novel soluble epoxide hydrolase inhibitor, GSK2256294, attenuates EET-mediated endothelial dysfunction in human resistance vessels both in vitro and in vivo. METHODS: Endogenous and stimulated endothelial release of EETs was assessed in 12 patients with COPD, 11 overweight smokers, and two matched control groups, using forearm plethysmography with intraarterial infusions of fluconazole, bradykinin, and the combination. The effects of GSK2256294 on EET-mediated vasodilation in human resistance arteries were assessed in vitro and in vivo in a phase I clinical trial in healthy overweight smokers. RESULTS: Compared with control groups, there was reduced vasodilation with bradykinin (P = .005), a blunted effect of fluconazole on bradykinin-induced vasodilation (P = .03), and a trend toward reduced basal EET/dihydroxyepoxyeicosatrienoic acid ratio in patients with COPD (P = .08). A similar pattern was observed in overweight smokers. In vitro, 10 μM GSK2256294 increased 11,12-EET-mediated vasodilation compared with vehicle (90% ± 4.2% vs 72.6% ± 6.2% maximal dilatation) and shifted the bradykinin half-maximal effective concentration (EC50) (-8.33 ± 0.172 logM vs -8.10 ± 0.118 logM; P = .001 for EC50). In vivo, 18 mg GSK2256294 improved the maximum bradykinin response from 338% ± 46% before a dose to 566% ± 110% after a single dose (P = .02) and to 503% ± 123% after a chronic dose (P = .003). CONCLUSIONS: GSK2256294 attenuates smoking-related EET-mediated endothelial dysfunction, suggesting potential therapeutic benefits in patients with COPD. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01762774; URL: www.clinicaltrials.gov.This work was supported by GSK [SEH114068] and Innovate UK (ERICA Consortium 10037625), the Wellcome Trust grant numbers 100780/Z/12/Z, and WT103782AIA awarded to LY, and DEN respectively; the Raymond and Beverley Sackler fellowship awarded to LY; National Institute for Health Research funding awarded to IBW, and JC in the Cambridge Comprehensive Biomedical Research, and the British Heart Foundation grant numbers CH/0 9/002, and RG66885 RCZA/008 awarded to DEN, and IBW. JLG and ZA are funded by the Medical Research Council (Medical Research Council Lipid Profiling and Signalling, MC UP A90 1006 & Lipid Dynamics and Regulation, MC PC 130 30)

Microeconomic institutions and personnel economics for health care delivery: a formal exploration of what matters to health workers in Rwanda

Background: Most developing countries face important challenges regarding the quality of health care and there is a growing consensus that health workers play a key role in this process. Our understanding as to what are the key institutional challenges in human resources, and their underlying driving forces, is more limited. A conceptual framework that structures existing insights and provides concrete directions for policy making is also missing. Methods: To gain a bottom up perspective we gather qualitative data through semi-structured interviews with different levels of health workers and users of health services in rural and urban Rwanda. We conducted discussions with 48 health workers and 25 users of health services in nine different groups in 2005. We maximized within-group heterogeneity by selecting participants using specific criteria that affect health worker performance and career choice. The discussion were analysed electronically, to identify key themes and insights, and are documented with a descriptive quantitative analysis relating to the associations between quotations. The findings from this research are then revisited ten years later making use of detailed follow up studies that have been carried out since then. Findings: The original discussions identified both key challenges in human resources for health, and driving forces of these challenges, as well as possible solutions. Two sets of issues were highlighted: those related to the size and distribution of the workforce, and those related to health workers’ on-the-job performance. Among the latter, four categories were identified: health workers’ poor attitudes towards patients, absenteeism, corruption and embezzlement, and lack of medical skills among some categories of health workers. The discussion suggest that four components constitute the deeper causal factors, which are, ranked in order of ease of malleability: incentives, monitoring arrangements, professional and workplace norms and intrinsic motivation. Three institutional innovations are identified that aim at improving performance: performance pay, community health workers and increased attention to training of health workers. Revisiting the findings from this primary research making use of later in depth studies, the analysis demonstrates their continued relevance and usefulness. We discuss how the different factors affect the quality of care by impacting on health worker performance and labour market choices, making use of insights from economics and development studies on the role of institutions. Conclusion: The study results indicates that health care quality to an important degree depends on four institutional factors at the micro level that strongly impact on health workers performance and career choice, and which deserve more attention in applied research and policy reform. The analysis also helps to identify ways forwards, which fit well with the Ministry’s most recent strategic plan

Unique Signatures of Natural Background Radiation on Human Y Chromosomes from Kerala, India

The most frequently observed major consequences of ionizing radiation are chromosomal lesions and cancers, although the entire genome may be affected. Owing to its haploid status and absence of recombination, the human Y chromosome is an ideal candidate to be assessed for possible genetic alterations induced by ionizing radiation. We studied the human Y chromosome in 390 males from the South Indian state of Kerala, where the level of natural background radiation (NBR) is ten-fold higher than the worldwide average, and that from 790 unexposed males as control.We observed random microdeletions in the Azoospermia factor (AZF) a, b and c regions in >90%, and tandem duplication and copy number polymorphism (CNP) of 11 different Y-linked genes in about 80% of males exposed to NBR. The autosomal homologues of Y-linked CDY genes largely remained unaffected. Multiple polymorphic copies of the Y-linked genes showing single Y-specific signals suggested their tandem duplication. Some exposed males showed unilocus duplication of DAZ genes resulting in six copies. Notably, in the AZFa region, approximately 25% of exposed males showed deletion of the DBY gene, whereas flanking genes USP9Y and UTY remained unaffected. All these alterations were detected in blood samples but not in the germline (sperm) samples.Exposure to high levels of NBR correlated with several interstitial polymorphisms of the human Y chromosome. CNPs and enhanced transcription of the SRY gene after duplication are envisaged to compensate for the loss of Y chromosome in some cells. The aforesaid changes, confined to peripheral blood lymphocytes, suggest a possible innate mechanism protecting the germline DNA from the NBR. Genome analysis of a larger population focusing on greater numbers of genes may provide new insights into the mechanisms and risks of the resultant genetic damages. The present work demonstrates unique signatures of NBR on human Y chromosomes from Kerala, India

MicroRNA interactome analysis predicts post-transcriptional regulation of ADRB2 and PPP3R1 in the hypercholesterolemic myocardium

Little is known about the molecular mechanism including microRNAs (miRNA) in hypercholesterolemia-induced cardiac dysfunction. We aimed to explore novel hypercholesterolemia-induced pathway alterations in the heart by an unbiased approach based on miRNA omics, target prediction and validation. With miRNA microarray we identified forty-seven upregulated and ten downregulated miRNAs in hypercholesterolemic rat hearts compared to the normocholesterolemic group. Eleven mRNAs with at least 4 interacting upregulated miRNAs were selected by a network theoretical approach, out of which 3 mRNAs (beta-2 adrenergic receptor [Adrb2], calcineurin B type 1 [Ppp3r1] and calcium/calmodulin-dependent serine protein kinase [Cask]) were validated with qRT-PCR and Western blot. In hypercholesterolemic hearts, the expression of Adrb2 mRNA was significantly decreased. ADRB2 and PPP3R1 protein were significantly downregulated in hypercholesterolemic hearts. The direct interaction of Adrb2 with upregulated miRNAs was demonstrated by luciferase reporter assay. Gene ontology analysis revealed that the majority of the predicted mRNA changes may contribute to the hypercholesterolemia-induced cardiac dysfunction. In summary, the present unbiased target prediction approach based on global cardiac miRNA expression profiling revealed for the first time in the literature that both the mRNA and protein product of Adrb2 and PPP3R1 protein are decreased in the hypercholesterolemic heart

A Family of Tree-Based Generators for Bubbles in Directed Graphs

International audienceBubbles are pairs of internally vertex-disjoint (s, t)-paths in a directed graph. In de Bruijn graphs built from reads of RNA and DNA data, bubbles represent interesting biological events, such as alternative splicing (AS) and allelic differences (SNPs and indels). However, the set of all bubbles in a de Bruijn graph built from real data is usually too large to be efficiently enumerated and analysed in practice. In particular, despite significant research done in this area, listing bubbles still remains the main bottleneck for tools that detect AS events in a reference-free context. Recently, in [1] the concept of a bubble generator was introduced as a way for obtaining a compact representation of the bubble space of a graph. Although this generator was quite effective in finding AS events, preliminary experiments showed that it is about 5 times slower than state-of-art methods. In this paper we propose a new family of bubble generators which improve substantially on the previous generator: generators in this new family are about two orders of magnitude faster and are still able to achieve similar precision in identifying AS events. To highlight the practical value of our new generators, we also report some experimental results on a real dataset

Role of 18F FDG PET/CT as a novel non-invasive biomarker of inflammation in chronic obstructive pulmonary disease

A characteristic feature of Chronic Obstructive Pulmonary Disease (COPD) is an abnormal inflammatory response in the lungs to inhaled particles or gases. The ability to assess and monitor this response in the lungs of COPD patients is important for understanding the pathogenic mechanisms, but also provides a measure of the activity of the disease. Disease activity is more likely to relate to lung inflammation rather than the degree of airflow limitation as measured by the FEV1. Preliminary studies have shown the 18F fluorodeoxyglucose positron emission tomography (18F FDG-PET) signal, as a measure of lung inflammation, is quantifiable in the lungs and is increased in COPD patients compared to controls. However, the methodology requires standardisation and any further enhancement of the methodology would improve its application to assess inflammation in the lungs. I investigated various methods of assessing FDG uptake in the lungs and assessed the reproducibility of these methods, and particularly evaluated whether the data was reproducible or not in the COPD patients (smokers and ex-smokers). This data was then compared with a group of healthy controls to assess the role of dynamic 18F FDG-PET scanning as a surrogate marker of lung inflammation. My data showed a good reproducibility of all methods of assessing FDG lung uptake. However, using conventional Patlak analysis, the uptake was not statistically different between COPD and the control group. Encouraging results in favour of COPD patients were nonetheless shown using compartmental methods of assessing the FDG lung uptake, suggesting the need to correct for the effect of air and blood (tissue fraction effect) when assessing this in a highly vascular organ like the lungs. A prospective study analysis involving a bigger cohort of COPD patients would be desirable to investigate this further