Extracellular matrix expansion is a key element of ventricular remodeling and a potential therapeutic target. Cardiovascular magnetic resonance (CMR) T1-mapping techniques are increasingly used to ...evaluate myocardial extracellular volume (ECV); however, the most widely applied methods are without histological validation. Our aim was to perform comprehensive validation of (1) dynamic-equilibrium CMR (DynEq-CMR), where ECV is quantified using hematocrit-adjusted myocardial and blood T1 values measured before and after gadolinium bolus; and (2) isolated measurement of myocardial T1, used as an ECV surrogate.
Whole-heart histological validation was performed using 96 tissue samples, analyzed for picrosirius red collagen volume fraction, obtained from each of 16 segments of the explanted hearts of 6 patients undergoing heart transplantation who had prospectively undergone CMR before transplantation (median interval between CMR and transplantation, 29 days). DynEq-CMR-derived ECV was calculated from T1 measurements made using a modified Look-Locker inversion recovery sequence before and 10 and 15 minutes post contrast. In addition, ECV was measured 2 to 20 minutes post contrast in 30 healthy volunteers. There was a strong linear relationship between DynEq-CMR-derived ECV and histological collagen volume fraction (P<0.001; within-subject: r=0.745; P<0.001; r(2)=0.555 and between-subject: r=0.945; P<0.01; r(2)=0.893; for ECV calculated using 15-minute postcontrast T1). Correlation was maintained throughout the entire heart. Isolated postcontrast T1 measurement showed significant within-subject correlation with histological collagen volume fraction (r=-0.741; P<0.001; r(2)=0.550 for 15-minute postcontrast T1), but between-subject correlations were not significant. DynEq-CMR-derived ECV varied significantly according to contrast dose, myocardial region, and sex.
DynEq-CMR-derived ECV shows a good correlation with histological collagen volume fraction throughout the whole heart. Isolated postcontrast T1 measurement is insufficient for ECV assessment.
Our sleep timing preference, or chronotype, is a manifestation of our internal biological clock. Variation in chronotype has been linked to sleep disorders, cognitive and physical performance, and ...chronic disease. Here we perform a genome-wide association study of self-reported chronotype within the UK Biobank cohort (n=100,420). We identify 12 new genetic loci that implicate known components of the circadian clock machinery and point to previously unstudied genetic variants and candidate genes that might modulate core circadian rhythms or light-sensing pathways. Pathway analyses highlight central nervous and ocular systems and fear-response-related processes. Genetic correlation analysis suggests chronotype shares underlying genetic pathways with schizophrenia, educational attainment and possibly BMI. Further, Mendelian randomization suggests that evening chronotype relates to higher educational attainment. These results not only expand our knowledge of the circadian system in humans but also expose the influence of circadian characteristics over human health and life-history variables such as educational attainment.
Objectives This study sought to evaluate the diagnostic performance of multiparametric cardiovascular magnetic resonance (CMR) for detecting cardiac allograft vasculopathy (CAV) using contemporary ...invasive epicardial artery and microvascular assessment techniques as reference standards, and to compare the performance of CMR with that of angiography. Background CAV continues to limit the long-term survival of heart transplant recipients. Coronary angiography has a Class I recommendation for CAV surveillance and annual or biannual surveillance angiography is performed routinely in most centers. Methods All transplant recipients referred for surveillance angiography at a single UK center over a 2-year period were prospectively screened for study eligibility. Patients prospectively underwent coronary angiography followed by coronary intravascular ultrasound, fractional flow reserve, and index of microcirculatory resistance. Within 1 month, patients underwent multiparametric CMR, including assessment of regional and global ventricular function, absolute myocardial blood flow quantification, and myocardial tissue characterization. In addition, 10 healthy volunteers underwent CMR. Results Forty-eight patients were recruited, median 7.1 years (interquartile range: 4.6 to 10.3 years) since transplantation. The CMR myocardial perfusion reserve was the only independent predictor of both epicardial (β = −0.57, p < 0.001) and microvascular disease (β = −0.60, p < 0.001) on stepwise multivariable regression. The CMR myocardial perfusion reserve significantly outperformed angiography for detecting moderate CAV (area under the curve, 0.89 95% confidence interval (CI): 0.79 to 1.00 vs. 0.59 95% CI: 0.42 to 0.77, p = 0.01) and severe CAV (area under the curve, 0.88 95% CI: 0.78 to 0.98 vs. 0.67 95% CI: 0.52 to 0.82, p = 0.05). Conclusions CAV, including epicardial and microvascular components, can be detected more accurately using noninvasive CMR-based absolute myocardial blood flow assessment than with invasive coronary angiography, the current clinical surveillance technique.
Chronic sleep disturbances, associated with cardiometabolic diseases, psychiatric disorders and all-cause mortality, affect 25-30% of adults worldwide. Although environmental factors contribute ...substantially to self-reported habitual sleep duration and disruption, these traits are heritable and identification of the genes involved should improve understanding of sleep, mechanisms linking sleep to disease and development of new therapies. We report single- and multiple-trait genome-wide association analyses of self-reported sleep duration, insomnia symptoms and excessive daytime sleepiness in the UK Biobank (n = 112,586). We discover loci associated with insomnia symptoms (near MEIS1, TMEM132E, CYCL1 and TGFBI in females and WDR27 in males), excessive daytime sleepiness (near AR-OPHN1) and a composite sleep trait (near PATJ (INADL) and HCRTR2) and replicate a locus associated with sleep duration (at PAX8). We also observe genetic correlation between longer sleep duration and schizophrenia risk (r
= 0.29, P = 1.90 × 10
) and between increased levels of excessive daytime sleepiness and increased measures for adiposity traits (body mass index (BMI): r
= 0.20, P = 3.12 × 10
; waist circumference: r
= 0.20, P = 2.12 × 10
).
Despite modern immunosuppressive regimes, acute rejection remains a leading cause of morbidity and mortality in heart transplant recipients. Clinical features are unreliable, and therefore, screening ...is performed in order to detect rejection, and hence, augment immunosuppressive therapy, at an early stage, with the aim of reducing short- and long-term sequelae. Histological analysis of right ventricular myocardial tissue obtained at endomyocardial biopsy remains the 'gold standard' surveillance technique; however 'biopsy-negative' rejection occurs in up to 20% of patients, the procedure is associated with uncommon but potentially serious complications and it is expensive. Non-invasive screening would, conceivably, be safer, more tolerable and cheaper, and could potentially allow more comprehensive monitoring. The evidence for non-invasive methods of diagnosing acute rejection, including assessment of myocardial deformation, myocardial tissue characterisation, electrophysiological monitoring, visualisation of cellular and molecular components of rejection and peripheral monitoring of immune activation, is reviewed.
The relationship between insomnia symptoms and cognitive performance is unclear, particularly at the population level. We conducted the largest examination of this association to date through ...analysis of the UK Biobank, a large population-based sample of adults aged 40–69 years. We also sought to determine associations between cognitive performance and self-reported chronotype, sleep medication use and sleep duration.
This cross-sectional, population-based study involved 477,529 participants, comprising 133,314 patients with frequent insomnia symptoms (age: 57.4 ± 7.7 years; 62.1% female) and 344,215 controls without insomnia symptoms (age: 56.1 ± 8.2 years; 52.0% female). Cognitive performance was assessed by a touchscreen test battery probing reasoning, basic reaction time, numeric memory, visual memory, and prospective memory. Adjusted models included relevant demographic, clinical, and sleep variables.
Frequent insomnia symptoms were associated with cognitive impairment in unadjusted models; however, these effects were reversed after full adjustment, leaving those with frequent insomnia symptoms showing statistically better cognitive performance over those without. Relative to intermediate chronotype, evening chronotype was associated with superior task performance, while morning chronotype was associated with the poorest performance. Sleep medication use and both long (>9 h) and short (<7 h) sleep durations were associated with impaired performance.
Our results suggest that after adjustment for potential confounding variables, frequent insomnia symptoms may be associated with a small statistical advantage, which is unlikely to be clinically meaningful, on simple neurocognitive tasks. Further work is required to examine the mechanistic underpinnings of an apparent evening chronotype advantage in cognitive performance and the impairment associated with morning chronotype, sleep medication use, and sleep duration extremes.
•How different aspects of sleep health relate to cognition is unclear.•We examined sleep and cognitive performance in ∼500,000 adults aged 40–69 years.•Unexpectedly, frequent insomnia symptoms were independently associated with better cognitive performance.•Sleep medication and long and short sleep durations were linked to cognitive impairment.•Morningness was linked to impairment, while eveningness showed superior performance.
Abstract Self-reported shorter/longer sleep duration, insomnia, and evening preference are associated with hyperglycaemia in observational analyses, with similar observations in small studies using ...accelerometer-derived sleep traits. Mendelian randomization (MR) studies support an effect of self-reported insomnia, but not others, on glycated haemoglobin (HbA1c). To explore potential effects, we used MR methods to assess effects of accelerometer-derived sleep traits (duration, mid-point least active 5-h, mid-point most active 10-h, sleep fragmentation, and efficiency) on HbA1c/glucose in European adults from the UK Biobank (UKB) (n = 73,797) and the MAGIC consortium (n = 146,806). Cross-trait linkage disequilibrium score regression was applied to determine genetic correlations across accelerometer-derived, self-reported sleep traits, and HbA1c/glucose. We found no causal effect of any accelerometer-derived sleep trait on HbA1c or glucose. Similar MR results for self-reported sleep traits in the UKB sub-sample with accelerometer-derived measures suggested our results were not explained by selection bias. Phenotypic and genetic correlation analyses suggested complex relationships between self-reported and accelerometer-derived traits indicating that they may reflect different types of exposure. These findings suggested accelerometer-derived sleep traits do not affect HbA1c. Accelerometer-derived measures of sleep duration and quality might not simply be ‘objective’ measures of self-reported sleep duration and insomnia, but rather captured different sleep characteristics.
Nigeria had the most AIDS-related deaths worldwide in 2014 (170,000), and 46% were associated with tuberculosis (TB). Although treatment of people living with HIV (PLHIV) with antiretroviral therapy ...(ART) reduces TB-associated morbidity and mortality, incident TB can occur while on ART. We estimated incidence and characterized factors associated with TB after ART initiation in Nigeria.
We analyzed retrospective cohort data from a nationally representative sample of adult patients on ART. Data were abstracted from 3,496 patient records, and analyses were weighted and controlled for a complex survey design. We performed domain analyses on patients without documented TB disease and used a Cox proportional hazard model to assess factors associated with TB incidence after ART.
At ART initiation, 3,350 patients (95.8%) were not receiving TB treatment. TB incidence after ART initiation was 0.57 per 100 person-years, and significantly higher for patients with CD4<50/μL (adjusted hazard ratio AHR: 4.2, 95% confidence interval CI: 1.4-12.7) compared with CD4≥200/μL. Patients with suspected but untreated TB at ART initiation and those with a history of prior TB were more likely to develop incident TB (AHR: 12.2, 95% CI: 4.5-33.5 and AHR: 17.6, 95% CI: 3.5-87.9, respectively).
Incidence of TB among PLHIV after ART initiation was low, and predicted by advanced HIV, prior TB, and suspected but untreated TB. Study results suggest a need for improved TB screening and diagnosis, particularly among high-risk PLHIV initiating ART, and reinforce the benefit of early ART and other TB prevention efforts.
With about 3.4 million HIV-infected persons, Nigeria has the second highest number of people living with HIV (PLHIV) in the world. However, antiretroviral treatment (ART) coverage in Nigeria remains ...low with only 748,846 (22%) of PLHIV on ART by the end of 2014. Retention of HIV-infected patients in pre-ART care is essential to ensure timely ART initiation. We assessed outcomes of patients enrolled in Nigeria's pre-ART program during 2004-2012.
We conducted a nationally representative retrospective cohort study among adults (≥15 years old), enrolling in pre-ART programs supported by the U.S. President's Emergency Plan for AIDS Relief in Nigeria. A total of 35 sites enrolling ≥50 patients in pre-ART were selected using probability proportional-to-size sampling; 2,415 eligible medical records at these sites were randomly selected for abstraction. Determinants of loss to follow-up (LTFU) and mortality during pre-ART care were estimated using Cox proportional hazards regression models.
The median age at enrollment was 32 years (interquartile range (IQR) 27-40). A total of 1,216 (51.4%) initiated ART by the time of data abstraction. Among the remaining 1,199 patients, 898 (74.9%) had been LTFU, 180 (15.0%) were alive and in pre-ART care, 71 (5.9%) had died, 50 (4.2%) had transferred out or stopped care. Baseline markers of advanced disease, including weight <45 kg (adjusted hazard ration (AHR) = 4.23; 95% confidence interval (CI): 1.51-15.58) and more advanced WHO disease stage, were predictive of pre-ART mortality. Compared with patients aged 15-24, patients aged 35-44 (AHR = 0.67; 95% CI: 1.0.47-0.95) and age 45-54 (AHR = 0.66; 95% CI: 0.48-0.91) had lower LTFU rates. Compared with attending facilities in North Central geopolitical zone, attending facility locations in South East (AHR = 0.44; 95% CI: 0.24-0.83) was protective against LTFU.
About half of patients enrolling in HIV program during 2004-2012 in Nigeria had not initiated ART by 2013. Key strategies to improve early ART initiation among pre-ART enrollees include implementation of the WHO test and treat guidelines, earlier HIV testing, and better monitoring to improve ART initiation rates. Further research to understand regional variations in pre-ART outcomes is warranted.
Pulmonary inflammatory responses lie under circadian control; however, the importance of circadian mechanisms in the underlying fibrotic phenotype is not understood. Here, we identify a striking ...change to these mechanisms resulting in a gain of amplitude and lack of synchrony within pulmonary fibrotic tissue. These changes result from an infiltration of mesenchymal cells, an important cell type in the pathogenesis of pulmonary fibrosis. Mutation of the core clock protein REVERBα in these cells exacerbated the development of bleomycin-induced fibrosis, whereas mutation of REVERBα in club or myeloid cells had no effect on the bleomycin phenotype. Knockdown of REVERBα revealed regulation of the little-understood transcription factor TBPL1. Both REVERBα and TBPL1 altered integrinβ1 focal-adhesion formation, resulting in increased myofibroblast activation. The translational importance of our findings was established through analysis of 2 human cohorts. In the UK Biobank, circadian strain markers (sleep length, chronotype, and shift work) are associated with pulmonary fibrosis, making them risk factors. In a separate cohort, REVERBα expression was increased in human idiopathic pulmonary fibrosis (IPF) lung tissue. Pharmacological targeting of REVERBα inhibited myofibroblast activation in IPF fibroblasts and collagen secretion in organotypic cultures from IPF patients, thus suggesting that targeting of REVERBα could be a viable therapeutic approach.
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