Genetic variability in the absorption of dietary sterols affects the risk of coronary artery disease.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadAims: To explore whether variability in dietary cholesterol and phytosterol absorption impacts the risk of coronary artery disease (CAD) using as instruments sequence variants in the ABCG5/8 genes, key regulators of intestinal absorption of dietary sterols. Methods and results: We examined the effects of ABCG5/8 variants on non-high-density lipoprotein (non-HDL) cholesterol (N up to 610 532) and phytosterol levels (N = 3039) and the risk of CAD in Iceland, Denmark, and the UK Biobank (105 490 cases and 844 025 controls). We used genetic scores for non-HDL cholesterol to determine whether ABCG5/8 variants confer greater risk of CAD than predicted by their effect on non-HDL cholesterol. We identified nine rare ABCG5/8 coding variants with substantial impact on non-HDL cholesterol. Carriers have elevated phytosterol levels and are at increased risk of CAD. Consistent with impact on ABCG5/8 transporter function in hepatocytes, eight rare ABCG5/8 variants associate with gallstones. A genetic score of ABCG5/8 variants predicting 1 mmol/L increase in non-HDL cholesterol associates with two-fold increase in CAD risk [odds ratio (OR) = 2.01, 95% confidence interval (CI) 1.75-2.31, P = 9.8 × 10-23] compared with a 54% increase in CAD risk (OR = 1.54, 95% CI 1.49-1.59, P = 1.1 × 10-154) associated with a score of other non-HDL cholesterol variants predicting the same increase in non-HDL cholesterol (P for difference in effects = 2.4 × 10-4). Conclusions: Genetic variation in cholesterol absorption affects levels of circulating non-HDL cholesterol and risk of CAD. Our results indicate that both dietary cholesterol and phytosterols contribute directly to atherogenesis. Keywords: ABCG5/8; Absorption; Dietary cholesterol; Genetics; Phytosterols.Novo Nordisk Foundation University College London Hospital National Institute for Health Research Biomedical Research Centr

Major lichen metabolites (1–7) and unknown minor compounds (a-c) in Icelandic <i>Melanelia</i> taxa.

<p>Major lichen metabolites (1–7) and unknown minor compounds (a-c) in Icelandic <i>Melanelia</i> taxa.</p

Chemical structures of major compounds in Icelandic <i>Melanelia</i> lichens.

<p>Compounds include cryptostictic acid <b>1</b>, stictic acid <b>2</b>, norstictic acid <b>3</b>, usnic acid <b>4</b>, stenosporic acid <b>5</b>, rangiformic acid <b>6</b> and perlatolic acid <b>7</b>.</p

Genetic distances, alignment length and number of specimens (haplotypes) for the genera <i>Melanelia</i> and <i>Montanelia</i>.

<p>Genetic distances, alignment length and number of specimens (haplotypes) for the genera <i>Melanelia</i> and <i>Montanelia</i>.</p

Multivariate analysis of LC-MS metabolite data.

<p>(A) PCA plot of chemical profiles of Icelandic <i>Melanelia</i> lichens, where <i>M</i>. <i>agnata</i> and <i>M</i>. <i>stygia</i> are clustered. (B) OPLS-DA plot shows the separation of the two <i>Melanelia</i> taxa. The metabolome of <i>M</i>. <i>agnata</i> and <i>M</i>. <i>stygia</i> can be differentiated with a high level of prediction value: R²Y(cum) = 1, Q²(com) = 0.99. (C) Loading S-plot from LC-MS data of <i>M</i>. <i>agnata</i> and <i>M</i>. <i>stygia</i>. Cut-off values of p(corr) < |0.8| were selected to designate the metabolites contribuiting significantly to the overall difference (area in color) between <i>M</i>. <i>agnata</i> and <i>M</i>. <i>stygia</i>. Two metabolites were thus identified from each species.</p

MS fragmentation patterns of depsidones in the lichen <i>Melanelia hepatizon</i>.

<p>Compounds include cryptostictic acid <b>1</b>, stictic acid <b>2</b> and norstictic acid <b>3</b>.</p

Fungal nrITS gene tree obtained from 116 <i>Melanelia</i> and <i>Montanelia</i> specimens.

<p>(A) Neighbor-joining tree, bootstrap values over 80% are labelled on the branches; (B) Maximum-likelihood tree, posterior probability/bootstrap values are labelled on branches.</p

Genetic distance histograms and barcoding gap analysis for reported <i>Melanelia</i> species in Iceland.

<p>(A and B) p-Distance histogram for the genus <i>Melanelia</i> and <i>Montanelia</i>, respectively; (C and D) Barcoding gap analysis for <i>Melanelia</i> species and <i>Montanelia disjuncta</i>.</p

MS fragmentation pathway of usnic acid.

<p>Usnic acid was detected in one chemotype of Icelandic <i>Montanelia disjuncta</i> taxon. Structure a, b, d, e and f are characteristic fragment ions in MS² spectrum (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0178012#pone.0178012.s004" target="_blank">S3 Fig</a>). Structure b is a resonance contributor of structure a but not a true structure of usnic acid. Structure c is only reported in LDI or FAB-MS. (Abbreviation: RDA: retro-Diels—Alder reaction; LDI/FAB: laser desorption ionization/fast atom bombardment).</p

Quantitative UPLC-MS/MS assay of urinary 2,8-dihydroxyadenine for diagnosis and management of adenine phosphoribosyltransferase deficiency.

To access publisher's full text version of this article click on the hyperlink at the bottom of the pageAdenine phosphoribosyltransferase (APRT) deficiency is a hereditary disorder that leads to excessive urinary excretion of 2,8-dihydroxyadenine (DHA), causing nephrolithiasis and chronic kidney disease. Treatment with allopurinol or febuxostat reduces DHA production and attenuates the renal manifestations. Assessment of DHA crystalluria by urine microscopy is used for therapeutic monitoring, but lacks sensitivity. We report a high-throughput assay based on ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) for quantification of urinary DHA. The UPLC-MS/MS assay was optimized by a chemometric approach for absolute quantification of DHA, utilizing isotopically labeled DHA as an internal standard. Experimental screening was conducted with D-optimal design and optimization of the DHA response was performed with central composite face design and related to the peak area of DHA using partial least square regression. Acceptable precision and accuracy of the DHA concentration were obtained over a calibration range of 100 to 5000ng/mL on three different days. The intra- and inter-day accuracy and precision coefficients of variation were well within ±15% for quality control samples analyzed in replicates of six at three concentration levels. Absolute quantification of DHA in urine samples from patients with APRT deficiency was achieved wihtin 6.5min. Measurement of DHA in 24h urine samples from three patients with APRT deficiency, diluted 1:15 (v/v) with 10mM ammonium hydroxide (NH4OH), yielded a concentration of 3021, 5860 and 10563ng/mL and 24h excretion of 816, 1327 and 1649mg, respectively. A rapid and robust UPLC-MS/MS assay for absolute quantification of DHA in urine was successfully developed. We believe this method will greatly facilitate diagnosis and management of patients with APRT deficiency.Rare Kidney Stone Consortium (U54DK083908), Rare Diseases Clinical Research Network (RDCRN), National Center for Advancing Translational Sciences (NCATS). National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK