Esteban Gonzalez Burchard and colleagues explore how making medical research more diverse would aid not only social justice but scientific quality and clinical effectiveness, too.
In epigenome-wide association studies (EWAS), different methylation profiles of distinct cell types may lead to false discoveries. We introduce ReFACTor, a method based on principal component ...analysis (PCA) and designed for the correction of cell type heterogeneity in EWAS. ReFACTor does not require knowledge of cell counts, and it provides improved estimates of cell type composition, resulting in improved power and control for false positives in EWAS. Corresponding software is available at http://www.cs.tau.ac.il/~heran/cozygene/software/refactor.html.
Background Asthma is an inflammatory condition often punctuated by episodic symptomatic worsening, and accordingly, patients with asthma might have waxing and waning adherence to controller therapy. ...Objective We sought to measure changes in inhaled corticosteroid (ICS) adherence over time and to estimate the effect of this changing pattern of use on asthma exacerbations. Methods ICS adherence was estimated from electronic prescription and fill information for 298 participants in the Study of Asthma Phenotypes and Pharmacogenomic Interactions by Race-Ethnicity. For each patient, we calculated a moving average of ICS adherence for each day of follow-up. Asthma exacerbations were defined as the need for oral corticosteroids, an asthma-related emergency department visit, or an asthma-related hospitalization. Proportional hazard models were used to assess the relationship between ICS medication adherence and asthma exacerbations. Results Adherence to ICS medications began to increase before the first asthma exacerbation and continued afterward. Adherence was associated with a reduction in exacerbations but was only statistically significant among patients whose adherence was greater than 75% of the prescribed dose (hazard ratio, 0.61; 95% CI, 0.41-0.90) when compared with patients whose adherence was 25% or less. This pattern was largely confined to patients whose asthma was not well controlled initially. An estimated 24% of asthma exacerbations were attributable to ICS medication nonadherence. Conclusions ICS adherence varies in the time period leading up to and after an asthma exacerbation, and nonadherence likely contributes to a large number of these exacerbations. High levels of adherence are likely required to prevent these events.
The goal of this study was to determine the effects of genetic variation in the organic cation transporter 1, OCT1, on the pharmacokinetics of the antidiabetic drug, metformin. Twenty healthy ...volunteers with known OCT1 genotype agreed to participate in the study. Each subject received two oral doses of metformin followed by collection of blood and urine samples. OCT1 genotypes had a significant (P<0.05) effect on metformin pharmacokinetics, with a higher area under the plasma concentration–time curve (AUC), higher maximal plasma concentration (Cmax), and lower oral volume of distribution (V/F) in the individuals carrying a reduced function OCT1 allele (R61C, G401S, 420del, or G465R). The effect of OCT1 on metformin pharmacokinetics in mice was less than in humans possibly reflecting species differences in hepatic expression level of the transporter. Our studies suggest that OCT1 genotype is a determinant of metformin pharmacokinetics.
Clinical Pharmacology & Therapeutics (2008) doi:10.1038/sj.clpt.6100275
Genomic imprinting is an important regulatory mechanism that silences one of the parental copies of a gene. To systematically characterize this phenomenon, we analyze tissue specificity of imprinting ...from allelic expression data in 1582 primary tissue samples from 178 individuals from the Genotype-Tissue Expression (GTEx) project. We characterize imprinting in 42 genes, including both novel and previously identified genes. Tissue specificity of imprinting is widespread, and gender-specific effects are revealed in a small number of genes in muscle with stronger imprinting in males. IGF2 shows maternal expression in the brain instead of the canonical paternal expression elsewhere. Imprinting appears to have only a subtle impact on tissue-specific expression levels, with genes lacking a systematic expression difference between tissues with imprinted and biallelic expression. In summary, our systematic characterization of imprinting in adult tissues highlights variation in imprinting between genes, individuals, and tissues.
Research in transformed immortalized cell lines indicates the cadherin-related family member 3 (CDHR3) protein serves as a receptor for human rhinovirus (HRV)–C. Similar experiments indicate that the ...CDHR3 coding variant rs6967330 increases CDHR3 protein surface expression.
We sought to determine whether CDHR3 is necessary for HRV-C infection of primary airway epithelial cells (AECs) and to identify molecular mechanisms by which CDHR3 variants confer risk for asthma exacerbations.
CDHR3 function and influence on HRV-C infection were investigated by using single-cell transcriptomics, CRISPR-Cas9 gene knockout, and genotype-specific donor experiments performed in primary AECs. Nasal airway epithelium cis–expression quantitative trait locus (eQTL) analysis of CDHR3 was performed, followed by association testing for asthma hospitalization in minority children.
CDHR3 lung expression is exclusive to ciliated AECs and associated with basal bodies during and after motile ciliogenesis. Knockout of CDHR3 in human AECs did not prevent ciliated cell differentiation but was associated with a decrease in transepithelial resistance and an 80% decrease in HRV-C infection of the mucociliary epithelium. AECs from subjects homozygous for the risk-associated rs6967330 single nucleotide polymorphism (SNP) exhibited greater HRV-C infection compared with cells homozygous for the nonrisk allele. AEC cis-eQTL analysis indicated that rs6967330 and other SNPs are eQTLs for CDHR3. Only the eQTL block containing the rs6967330 SNP showed a significant association with childhood asthma hospitalization.
Genetic deletion and genotype-specific studies in primary AECs indicate CDHR3 is critical to HRV-C infection of ciliated cells. The rs6967330 SNP confers risk of severe childhood asthma exacerbations, likely through increasing HRV-C infection levels and protein surface localization.
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The aim of this study was to investigate travel-associated morbidity in European travellers in 2009 in comparison with 2008, with a particular emphasis on emerging infectious diseases with the ...potential for introduction into Europe. Diagnoses with demographic, clinical and travel-related predictors of disease from ill returning travelers presenting to 12 core EuroTravNet sites from January to December 2009 were analysed. A total of 6392 patients were seen at EuroTravNet core sites in 2009, as compared with 6957 in 2008. As compared with 2008, there was a marked increase in the number of travellers exposed in North America and western Europe. Respiratory illnesses, in particular pandemic A(HINI) influenza, influenza-like syndromes, and tuberculosis, were also observed more frequently. A significant increase in reported dengue cases in 2009 as compared with 2008 was observed (n = 172, 2.7% vs. n = 131, 1.90%) (p 0.002). The numbers of malaria and chikungunya cases were also increasing, although not significantly. Two deaths were recorded: visceral leishmaniasis and sepsis in a Sudanese migrant, and Acinetobacter sp. pneumonia in a patient who had visited Spain. This is the most comprehensive hensy of travel-related illness in Europe in 2009 as compared with 2008. A significant increase in travel-related respiratory and vector-borne infections was observed, highlighting the potential risk for introduction of these diseases into Europe, where competent vectors are present. The number of traveller deaths is probably underestimated. The possible role of the travellers in the emergence of infectious diseases of public health concern is highlighted.
Asthma and chronic obstructive pulmonary disease (COPD) are highly prevalent chronic obstructive lung diseases with an associated high burden of disease. Asthma, which is often allergic in origin, ...frequently begins in infancy or childhood with variable airflow obstruction and intermittent wheezing, cough, and dyspnea. Patients with COPD, in contrast, are usually current or former smokers who present after the age of 40 years with symptoms (often persistent) including dyspnea and a productive cough. On the basis of age and smoking history, it is often easy to distinguish between asthma and COPD. However, some patients have features compatible with both diseases. Because clinical studies typically exclude these patients, their underlying disease mechanisms and appropriate treatment remain largely uncertain. To explore the status of and opportunities for research in this area, the NHLBI, in partnership with the American Thoracic Society, convened a workshop of investigators in San Francisco, California on May 14, 2016. At the workshop, current understanding of asthma-COPD overlap was discussed among clinicians, pathologists, radiologists, epidemiologists, and investigators with expertise in asthma and COPD. They considered knowledge gaps in our understanding of asthma-COPD overlap and identified strategies and research priorities that will advance its understanding. This report summarizes those discussions.
Air pollution is a known asthma trigger and has been associated with short-term asthma symptoms, airway inflammation, decreased lung function, and reduced response to asthma rescue medications.
To ...assess a causal relationship between air pollution and childhood asthma using data that address temporality by estimating air pollution exposures before the development of asthma and to establish the generalizability of the association by studying diverse racial/ethnic populations in different geographic regions.
This study included Latino (n = 3,343) and African American (n = 977) participants with and without asthma from five urban regions in the mainland United States and Puerto Rico. Residential history and data from local ambient air monitoring stations were used to estimate average annual exposure to five air pollutants: ozone, nitrogen dioxide (NO₂), sulfur dioxide, particulate matter not greater than 10 μm in diameter, and particulate matter not greater than 2.5 μm in diameter. Within each region, we performed logistic regression to determine the relationship between early-life exposure to air pollutants and subsequent asthma diagnosis. A random-effects model was used to combine the region-specific effects and generate summary odds ratios for each pollutant.
After adjustment for confounders, a 5-ppb increase in average NO₂ during the first year of life was associated with an odds ratio of 1.17 for physician-diagnosed asthma (95% confidence interval, 1.04-1.31).
Early-life NO₂ exposure is associated with childhood asthma in Latinos and African Americans. These results add to a growing body of evidence that traffic-related pollutants may be causally related to childhood asthma.
Background:
Substantial progress has been made toward unraveling the genetic architecture of multiple sclerosis (MS) within populations of European ancestry, but few genetic studies have focused on ...Hispanic and African American populations within the United States.
Objective:
We sought to test the relevance of common European MS risk variants outside of the major histocompatibility complex (n = 200) within these populations.
Methods:
Genotype data were available on 2652 Hispanics (1298 with MS, 1354 controls) and 2435 African Americans (1298 with MS, 1137 controls). We conducted single variant, pathway, and cumulative genetic risk score analyses.
Results:
We found less replication than statistical power suggested, particularly among African Americans. This could be due to limited correlation between the tested and causal variants within the sample or alternatively could indicate allelic and locus heterogeneity. Differences were observed between pathways enriched among the replicating versus all 200 variants. Although these differences should be examined in larger samples, a potential role exists for gene–environment or gene–gene interactions which alter phenotype differentially across racial and ethnic groups. Cumulative genetic risk scores were associated with MS within each study sample but showed limited diagnostic capability.
Conclusion:
These findings provide a framework for fine-mapping efforts in multi-ethnic populations of MS.
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