1,135 research outputs found

    Cardiac action of the first G protein biased small molecule apelin agonist.

    Get PDF
    Apelin peptide analogues displaying bias towards G protein signalling pathways have beneficial cardiovascular actions compared with the native peptide in humans in vivo. Our aim was to determine whether small molecule agonists could retain G protein bias. We have identified a biased small molecule, CMF-019, and characterised it in vitro and in vivo. In competition radioligand binding experiments in heart homogenates, CMF-019 bound to the human, rat and mouse apelin receptor with high affinity (pKi=8.58±0.04, 8.49±0.04 and 8.71±0.06 respectively). In cell-based functional assays, whereas, CMF-019 showed similar potency for the Gαi pathway to the endogenous agonist [Pyr(1)]apelin-13 (pD2=10.00±0.13 vs 9.34±0.15), in β-arrestin and internalisation assays it was less potent (pD2=6.65±0.15 vs 8.65±0.10 and pD2=6.16±0.21 vs 9.28±0.10 respectively). Analysis of these data demonstrated a bias of ∼400 for the Gαi over the β-arrestin pathway and ∼6000 over receptor internalisation. CMF-019 was tested for in vivo activity using intravenous injections into anaesthetised male Sprague-Dawley rats fitted with a pressure-volume catheter in the left ventricle. CMF-019 caused a significant increase in cardiac contractility of 606±112mmHg/s (p<0.001) at 500nmol. CMF-019 is the first biased small molecule identified at the apelin receptor and increases cardiac contractility in vivo. We have demonstrated that Gαi over β-arrestin/internalisation bias can be retained in a non-peptide analogue and predict that such bias will have the therapeutic benefit following chronic use. CMF-019 is suitable as a tool compound and provides the basis for design of biased agonists with improved pharmacokinetics for treatment of cardiovascular conditions such as pulmonary arterial hypertension.British Heart Foundation [FS/14/59/31282]; Wellcome Trust [WT107715/Z/15/Z], Wellcome Trust Programme in Metabolic and Cardiovascular Disease [096822/Z/11/Z]; Medical Research Council [MRC MC PC 14116]; Pulmonary Hypertension Association UK; Cambridge Biomedical Research Centre Biomedical Resources Grant University of Cambridge [099156/Z/12/Z]; Engineering and Physical Sciences Research Council [EP/M506552/1]; Biomedical Health Research Centre, University of Leed

    The HAT TRICK programme for improving physical activity, healthy eating and connectedness among overweight, inactive men: study protocol of a pragmatic feasibility trial.

    Full text link
    INTRODUCTION: Physical activity, healthy eating and maintaining a healthy weight are associated with reduced risk of cardiovascular disease, type 2 diabetes and cancer and with improved mental health. Despite these benefits, many men do not meet recommended physical activity guidelines and have poor eating behaviours. Many health promotion programmes hold little appeal to men and consequently fail to influence men's health practices. HAT TRICK was designed as a 12-week face-to-face, gender-sensitised intervention for overweight and inactive men focusing on physical activity, healthy eating and social connectedness and was delivered in collaboration with a major junior Canadian ice hockey team (age range 16-20 years). The programme was implemented and evaluated to assess its feasibility. This article describes the intervention design and study protocol of HAT TRICK. METHODS AND ANALYSIS: HAT TRICK participants (n=60) were men age 35 years, residing in the Okanagan Region of British Columbia, who accumulate 150 min of moderate to vigorous physical activity a week, with a body mass index of >25 kg/m2 and a pant waist size of >38'. Each 90 min weekly session included targeted health education and theory-guided behavioural change techniques, as well as a progressive (ie, an increase in duration and intensity) group physical activity component. Outcome measures were collected at baseline, 12 weeks and 9 months and included the following: objectively measured anthropometrics, blood pressure, heart rate, physical activity and sedentary behaviour, as well as self-reported physical activity, sedentary behaviour, diet, smoking, alcohol consumption, sleep habits, risk of depression, health-related quality of life and social connectedness. Programme feasibility data (eg, recruitment, satisfaction, adherence, content delivery) were assessed at 12 weeks via interviews and self-report. ETHICS AND DISSEMINATION: Ethical approval was obtained from the University of British Columbia Okanagan Behavioural Research Ethics Board (reference no H1600736). Study findings will be disseminated through academic meetings, peer-reviewed publication, web-based podcasts, social media, plain language summaries and co-delivered community presentations. TRIAL REGISTRATION NUMBER: ISRCTN43361357,Pre results

    Utilizing RE-AIM to examine the translational potential of Project MOVE, a novel intervention for increasing physical activity levels in breast cancer survivors

    Full text link
    Translating effective research into community practice is critical for improving breast cancer (BC) survivor health. The purpose of this study is to utilize the RE-AIM framework to evaluate the translational potential of Project MOVE, an innovative intervention focused on increasing physical activity (PA) in BC survivors. A mixed-methods design, including a self-report questionnaire, accelerometry, focus groups, and interviews, was used to inform each RE-AIM dimension. Reach was evaluated by the representativeness of participants. Effectiveness was reflected by change in PA levels and perceptions of satisfaction and acceptability. Adoption was examined using participants’ perceived barriers/facilitators to program uptake. Implementation was examined by participants’ perceived barriers/facilitators to implementing the program. Maintenance was assessed by participant retention. Assessments occurred at baseline and 6-months. Mixed analysis of variance and content analysis were used to analyze the data. A total of 87 participants participated in Project MOVE and were demographically comparable to similar studies (Reach). Participants indicated high levels of program satisfaction (88%) and previously inactive survivors’ significantly increased PA levels from baseline to 6-month follow-up (Effectiveness). Participants reported that a program focused on PA rather than disease helped them overcome barriers to PA (Adoption) and having leaders with BC and exercise expertise was essential to accommodate population specific barriers (Implementation). At 6-months, participant retention was 83% (Maintenance). Project MOVE is an acceptable, practical, and effective program for engaging BC survivors in PA and has the potential to be highly transferable to other populations and regions

    What Drives the Intensification of Mesoscale Convective Systems over the West African Sahel under Climate Change?

    Get PDF
    Extreme rainfall is expected to increase under climate change, carrying potential socioeconomic risks. However, the magnitude of increase is uncertain. Over recent decades, extreme storms over the West African Sahel have increased in frequency, with increased vertical wind shear shown to be a cause. Drier midlevels, stronger cold pools, and increased storm organization have also been observed. Global models do not capture the potential effects of lower- to midtropospheric wind shear or cold pools on storm organization since they parameterize convection. Here we use the first convection-permitting simulations of African climate change to understand how changes in thermodynamics and storm dynamics affect future extreme Sahelian rainfall. The model, which simulates warming associated with representative concentration pathway 8.5 (RCP8.5) until the end of the twenty-first century, projects a 28% increase of the extreme rain rate of MCSs. The Sahel moisture change on average follows Clausius–Clapeyron scaling, but has regional heterogeneity. Rain rates scale with the product of time-of-storm total column water (TCW) and in-storm vertical velocity. Additionally, prestorm wind shear and convective available potential energy both modulate in-storm vertical velocity. Although wind shear affects cloud-top temperatures within our model, it has no direct correlation with precipitation rates. In our model, projected future increase in TCW is the primary explanation for increased rain rates. Finally, although colder cold pools are modeled in the future climate, we see no significant change in near-surface winds, highlighting avenues for future research on convection-permitting modeling of storm dynamics

    Changes in urinary metabolomic profile during relapsing renal vasculitis

    Get PDF
    Current biomarkers of renal disease in systemic vasculitis lack predictive value and are insensitive to early damage. To identify novel biomarkers of renal vasculitis flare, we analysed the longitudinal urinary metabolomic profile of a rat model of anti-neutrophil cytoplasmic antibody (ANCA) vasculitis. Wistar-Kyoto (WKY) rats were immunised with human myeloperoxidase (MPO). Urine was obtained at regular intervals for 181 days, after which relapse was induced by re-challenge with MPO. Urinary metabolites were assessed in an unbiased fashion using nuclear magnetic resonance (NMR) spectroscopy, and analysed using partial least squares discriminant analysis (PLS-DA) and partial least squares regression (PLS-R). At 56 days post-immunisation, we found that rats with vasculitis had a significantly different urinary metabolite profile than control animals; the observed PLS-DA clusters dissipated between 56 and 181 days, and re-emerged with relapse. The metabolites most altered in rats with active or relapsing vasculitis were trimethylamine N-oxide (TMAO), citrate and 2-oxoglutarate. Myo-inositol was also moderately predictive. The key urine metabolites identified in rats were confirmed in a large cohort of patients using liquid chromatography-mass spectrometry (LC-MS). Hypocitraturia and elevated urinary myo-inositol remained associated with active disease, with the urine myo-inositol:citrate ratio being tightly correlated with active renal vasculitis

    Clinical implications of having reduced mid forced expiratory flow rates (FEF25-75), independently of FEV1, in adult patients with asthma

    Get PDF
    INTRODUCTION:FEF25-75 is one of the standard results provided in spirometry reports; however, in adult asthmatics there is limited information on how this physiological measure relates to clinical or biological outcomes independently of the FEV1 or the FEV1/FVC ratio. PURPOSE:To determine the association between Hankinson's percent-predicted FEF25-75 (FEF25-75%) levels with changes in healthcare utilization, respiratory symptom frequency, and biomarkers of distal airway inflammation. METHODS:In participants enrolled in the Severe Asthma Research Program 1-2, we compared outcomes across FEF25-75% quartiles. Multivariable analyses were done to avoid confounding by demographic characteristics, FEV1, and the FEV1/FVC ratio. In a sensitivity analysis, we also compared outcomes across participants with FEF25-75% below the lower limit of normal (LLN) and FEV1/FVC above LLN. RESULTS:Subjects in the lowest FEF25-75% quartile had greater rates of healthcare utilization and higher exhaled nitric oxide and sputum eosinophils. In multivariable analysis, being in the lowest FEF25-75% quartile remained significantly associated with nocturnal symptoms (OR 3.0 [95%CI 1.3-6.9]), persistent symptoms (OR 3.3 [95%CI 1-11], ICU admission for asthma (3.7 [1.3-10.8]) and blood eosinophil % (0.18 [0.07, 0.29]). In the sensitivity analysis, those with FEF25-75% <LLN had significantly more nocturnal and persistent symptoms, emergency room visits, higher serum eosinophil levels and increased methacholine responsiveness. CONCLUSIONS:After controlling for demographic variables, FEV1 and FEV1/FVC, a reduced FEF25-75% is independently associated with previous ICU admission, persistent symptoms, nocturnal symptoms, blood eosinophilia and bronchial hyperreactivity. This suggests that in some asthmatics, a reduced FEF25-75% is an independent biomarker for more severe asthma

    The human semicircular canal model of galvanic vestibular stimulation

    Get PDF
    A vector summation model of the action of galvanic stimuli on the semicircular canals has been shown to explain empirical balance and perceptual responses to binaural-bipolar stimuli. However, published data suggest binaural-monopolar stimuli evoke responses that are in the reverse direction of the model prediction. Here, we confirm this by measuring balance responses to binaural-monopolar stimulation as movements of the upper trunk. One explanation for the discrepancy is that the galvanic stimulus might evoke an oppositely directed balance response from the otolith organs that sums with and overrides the semicircular canal response. We tested this hypothesis by measuring sway responses across the full range of head pitch. The results showed some modulation of sway with pitch such that the maximal response occurred with the head in the primary position. However, the effect fell a long way short of that required to reverse the canal sway response. This indicates that the model is incomplete. Here, we examine alterations to the model that could explain both the bipolar and monopolar-evoked behavioural responses. An explanation was sought by remodelling the canal response with more recent data on the orientation of the individual canals. This improved matters but did not reverse the model prediction. However, the model response could be reversed by either rotating the entire labyrinth in the skull or by altering the gains of the individual canals. The most parsimonious solution was to use the more recent canal orientation data coupled with a small increase in posterior canal gain

    Breath Formate Is a Marker of Airway S-Nitrosothiol Depletion in Severe Asthma

    Get PDF
    -nitrosothiols (SNOs), a class of endogenous airway smooth muscle relaxants. This deficiency results from increased activity of an enzyme that both reduces SNOs to ammonia and oxidizes formaldehyde to formic acid, a volatile carboxylic acid that is more easily detected in exhaled breath condensate (EBC) than SNOs. We therefore hypothesize that depletion of airway SNOs is related to asthma pathology, and breath formate concentration may be a proxy measure of SNO catabolism. (r = −0.39, p = 0.002, asthmatics only), and positively correlated with the NO-derived ion nitrite (r = 0.46, p<0.0001) as well as with total serum IgE (r = 0.28, p = 0.016, asthmatics only). Furthermore, formate was not significantly correlated with other volatile organic acids nor with inhaled corticosteroid dose.-nitrosothiols
    corecore