203 research outputs found

    Enhanced GRK2 expression and desensitization of betaAR vasodilatation in hypertensive patients.

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    Increased levels of G protein coupled receptor kinase GRK2 appear to participate in hypertension presumably through the desensitization of beta adrenergic receptors (betaARs) that mediate vasodilatation. There are contrasting data on the occurrence of betaAR desensitization in the vasculature, we therefore investigated betaAR vasodilatation and desensitization in normotensives and in hypertensive humans. In blood lymphocytes, we assessed betaAR signaling and GRK2 expression and found betaAR signaling alterations and, consistent with desensitization, ncreased GRK2 levels in hypertensives. We studied in vivo vasodilatation to the betaAR agonist isoproterenol (ISO) injected in the brachia artery in control conditions and during the concomitant infusion of heparin, a known in vitro nonspecific GRK inhibitor. ISO induced a dose-dependent vasorelaxation that was attenuated in hypertensives indicating a loss of betaAR signaling. Intra-arterial infusion of heparin nhibited lymphocyte GRK2 activity and prevented desensitization of betaAR vasodilatation in normotensives. In hypertensives, heparin restored vasodilatation to ISO, to levels observed in normotensives. Our results suggest that betaAR desensitization does indeed occur at the vascular levels in vivo, and that heparin by acting as a GRK inhibitor prevents this in normotensives and restores impaired betaAR vasodilation in hypertensives. We conclude that desensitization participates to impaired betaAR vasodilation in hypertension

    Structure activity relationships of αv integrin antagonists for pulmonary fibrosis by variation in aryl substituents

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    Antagonism of alphav beta6 is emerging as a potential treatment of idiopathic pulmonary fibrosis based on strong target validation. Starting from an alphav beta3 antagonist lead and through simple variation in the nature and position of aryl substituent, the discovery of compounds with improved alphav beta6 activity is described. The compounds also have physicochemical properties commensurate with oral bioavailability and are high quality starting points for a drug discovery programme. Compounds 33S and 43E1 are pan alphav antagonists having ca 100 nM potency against alphav beta3, alphav beta5, alphav beta6 and alphav beta8 in cell adhesion assays. Detailed structure activity relationships with these integrins are described which also reveal substituents providing partial selectivity (defined as at least a 0.7 log difference in pIC50 values between the integrins in question) for alphav beta3 and alphav beta5

    The possible role of chromosome X variability in hypertensive familiarity

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    Familiarity participates in the pathogenesis of hypertension, although only recently, whole genome studies have proposed regions of the human genome possibly involved in the transmission of the hypertensive phenotype. Although studies have mainly focused on autosome, hitherto the influence of sex on familial transmission of hypertension has not been considered. We analysed the database of the Campania Salute Network of Hypertension center of the Federico II University Hospital of Naples (Italy), using dichotomous variables for paternal and maternal familiarity and gender (male and female) of 12 504 hypertensive patients (6868 males and 5636 females) and 6352 controls (3484 males and 2868 females), totaling 18 856 subjects. In the hypertensive group, familiarity was present in 75% of cases with odds of 3.77 and in only 26% of the normotensives with odds of 0.94. The odds ratio (OR) indicated that familiarity increases the risk of developing hypertension by 2.91 (95% confidence interval (CI)=2.67–3.17, P<0.001) times. Additionally, maternal familiarity was 37% (OR=3.01, 95% CI=2.66–3.41, P<0.001), paternal familiarity was 21% (OR=2.31, 95% CI=2.01–2.68, P<0.001) and the double familiarity was 17% (OR=3.45, 95% CI=2.87–4.01, P<0.001), thus suggesting a plausible association between maternal familiarity and development of hypertension; this finding was observed both in male and in female patients, although the phenomenon was larger in males. Given the dominance of maternal transmission in males, by genome-wide analysis of the X chromosome, we found two regions that were differently distributed in male hypertensives with maternal hypertension. Our data highlight the importance of genetic variants in the X chromosome to the maternal transmission of the hypertensive phenotype

    Pinpointing beta adrenergic receptor in ageing pathophysiology: victim or executioner? Evidence from crime scenes

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    ADEPT - Abnormal Doppler Enteral Prescription Trial

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    <p>Abstract</p> <p>Background</p> <p>Pregnancies complicated by abnormal umbilical artery Doppler blood flow patterns often result in the baby being born both preterm and growth-restricted. These babies are at high risk of milk intolerance and necrotising enterocolitis, as well as post-natal growth failure, and there is no clinical consensus about how best to feed them. Policies of both early milk feeding and late milk feeding are widely used. This randomised controlled trial aims to determine whether a policy of early initiation of milk feeds is beneficial compared with late initiation. Optimising neonatal feeding for this group of babies may have long-term health implications and if either of these policies is shown to be beneficial it can be immediately adopted into clinical practice.</p> <p>Methods and Design</p> <p>Babies with gestational age below 35 weeks, and with birth weight below 10th centile for gestational age, will be randomly allocated to an "early" or "late" enteral feeding regimen, commencing milk feeds on day 2 and day 6 after birth, respectively. Feeds will be gradually increased over 9-13 days (depending on gestational age) using a schedule derived from those used in hospitals in the Eastern and South Western Regions of England, based on surveys of feeding practice. Primary outcome measures are time to establish full enteral feeding and necrotising enterocolitis; secondary outcomes include sepsis and growth. The target sample size is 400 babies. This sample size is large enough to detect a clinically meaningful difference of 3 days in time to establish full enteral feeds between the two feeding policies, with 90% power and a 5% 2-sided significance level. Initial recruitment period was 24 months, subsequently extended to 38 months.</p> <p>Discussion</p> <p>There is limited evidence from randomised controlled trials on which to base decisions regarding feeding policy in high risk preterm infants. This multicentre trial will help to guide clinical practice and may also provide pointers for future research.</p> <p>Trial registration</p> <p>Current Controlled Trials ISRCTN: 87351483</p

    Comprehensive analysis of epigenetic clocks reveals associations between disproportionate biological ageing and hippocampal volume

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    The concept of age acceleration, the difference between biological age and chronological age, is of growing interest, particularly with respect to age-related disorders, such as Alzheimer’s Disease (AD). Whilst studies have reported associations with AD risk and related phenotypes, there remains a lack of consensus on these associations. Here we aimed to comprehensively investigate the relationship between five recognised measures of age acceleration, based on DNA methylation patterns (DNAm age), and cross-sectional and longitudinal cognition and AD-related neuroimaging phenotypes (volumetric MRI and Amyloid-β PET) in the Australian Imaging, Biomarkers and Lifestyle (AIBL) and the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Significant associations were observed between age acceleration using the Hannum epigenetic clock and cross-sectional hippocampal volume in AIBL and replicated in ADNI. In AIBL, several other findings were observed cross-sectionally, including a significant association between hippocampal volume and the Hannum and Phenoage epigenetic clocks. Further, significant associations were also observed between hippocampal volume and the Zhang and Phenoage epigenetic clocks within Amyloid-β positive individuals. However, these were not validated within the ADNI cohort. No associations between age acceleration and other Alzheimer’s disease-related phenotypes, including measures of cognition or brain Amyloid-β burden, were observed, and there was no association with longitudinal change in any phenotype. This study presents a link between age acceleration, as determined using DNA methylation, and hippocampal volume that was statistically significant across two highly characterised cohorts. The results presented in this study contribute to a growing literature that supports the role of epigenetic modifications in ageing and AD-related phenotypes
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