Primary biliary cirrhosis (PBC) is a classical autoimmune liver disease for which effective immunomodulatory therapy is lacking. Here we perform meta-analyses of discovery datasets from genome-wide association studies of European subjects (n=2,764 cases and 10,475 controls) followed by validation genotyping in an independent cohort (n=3,716 cases and 4261 controls). We discover and validate six previously unknown risk loci for PBC (Pcombined<5×10−8) and used pathway analysis to identify JAK-STAT/IL12/IL27 signaling and cytokine-cytokine pathways, for which relevant therapies exist.
The development of magnetic resonance imaging (MRI) for use in medical investigation has provided a huge forward leap in the field of diagnosis, particularly with avoidance of exposure to potentially dangerous ionizing radiation. With decreasing costs and better availability, the use of MRI is becoming ever more pervasive throughout clinical practice. Understanding the principles underlying this imaging modality and its multiple applications can be used to appreciate the benefits and limitations of its use, further informing clinical decisionmaking. In this article, the principles of MRI are reviewed, with further discussion of specific clinical applications such as parallel, diffusion-weighted, and magnetization transfer imaging. MR spectroscopy is also considered, with an overview of key metabolites and how they may be interpreted. Finally, a brief view on how the use of MRI will change over the coming years is presented. ( J CLIN EXP HEPATOL 2015;5:246-255) T he nuclear magnetic resonance (NMR) phenomenon was first described experimentally by both Bloch and Purcell in 1946, for which they were both awarded the Nobel Prize for Physics in 1952.1,2 The technique has rapidly evolved since then, following the introduction of wide-bore superconducting magnets (approximately 30 years ago), allowing development of clinical applications. The first clinical magnetic resonance images were produced in Nottingham and Aberdeen in 1980, and magnetic resonance imaging (MRI) is now a widely available, powerful clinical tool. 3,4 This article covers a brief synopsis of basic principles in MRI, followed by an overview of current applications in medical practice.All atomic nuclei consist of protons and neutrons, with a net positive charge. Certain atomic nuclei, such as the hydrogen nucleus, 1 H, or the phosphorus nucleus, 31 P, possess a property known as ''spin'', dependent on the number of protons. This can be conceived as the nucleus spinning around its own axis although this is a mathematical analogy. The nucleus itself does not spin in the classical meaning but by virtue of its constituent parts induces a magnetic moment, generating a local magnetic field with north and south poles. The quantum mechanical description of this dipolar magnet is analogous to classical mechanics of spinning objects. The dipole itself is analogous to a bar magnet, with magnetic poles aligning along its axis of rotation (Figure 1 , ). 5Application of a strong, external magnetic field (B 0 ) aligns the nucleus either in parallel with or perpendicular to the external field. A liquid solution containing many nuclear spins, placed within the B 0 field, will contain nuclear spins in one of two energy states: a low-energy state (oriented parallel to the magnetic field) or a high-energy state (orientated perpendicular to the magnetic field direction). In solids or liquids, there would tend to be an excess of spins in the same direction as B 0 . Although a bar magnet would orientate completely parallel or antiparallel to the field, the nucleus has an...
Proton pump inhibitors (PPI) have been associated with infectious complications in cirrhosis, but their impact on distal gut microbiota composition and function is unclear. We aimed to evaluate changes in stool microbiota composition and function in patients with cirrhosis and healthy controls after omeprazole therapy. Both 15 compensated cirrhotic patients and 15 age-matched controls underwent serum gastrin measurement, stool microbiota profiling with multitagged pyrosequencing, and urinary metabolic profiling with NMR spectroscopy to assess microbial cometabolites before/after a 14-day course of 40 mg/day omeprazole under constant diet conditions. Results before (pre) and after PPI were compared in both groups, compared with baseline by systems biology techniques. Adherence was >95% without changes in diet or MELD (model for end-stage liver disease) score during the study. Serum gastrin concentrations significantly increased after PPI in cirrhosis (pre 38.3 ± 35.8 vs. 115.6 ± 79.3 pg/ml P < 0.0001) and controls (pre 29.9 ± 14.5 vs. 116.0 ± 74.0 pg/ml, P = 0.001). A significant microbiota change was seen in both controls and cirrhosis after omeprazole (QIIME P < 0.0001). Relative Streptococcaceae abundance, normally abundant in saliva, significantly increased postomeprazole in controls (1 vs. 5%) and cirrhosis (0 vs. 9%) and was correlated with serum gastrin levels (r = 0.4, P = 0.005). We found significantly reduced hippurate in cirrhosis vs. controls both pre- and postomeprazole and increased lactate in both groups post vs. preomeprazole, whereas dimethylamine (DMA) decreased in cirrhosis only. On correlation network analysis, significant changes in linkages of bacteria with metabolites (hippurate/DMA/lactate) were found postomeprazole, compared with pre-PPI in cirrhosis patients. In conclusion, omeprazole is associated with a microbiota shift and functional change in the distal gut in patients with compensated cirrhosis that could set the stage for bacterial overgrowth.
The advent of metabonomics has seen a proliferation of biofluid profiling studies of patients with hepatocellular carcinoma. The majority of these studies have been conducted in single indigenous populations making the widespread applicability of candidate metabolite biomarkers difficult. Presented here is a urinary proton nuclear magnetic resonance spectroscopy study of mainly hepatitis C virus infected Egyptian patients with hepatocellular carcinoma, which corroborates findings of a previous study from our group of mainly hepatitis B-infected Nigerian patients with hepatocellular carcinoma. Using multivariate statistical analysis, in the form of orthogonal signal-corrected partial least squared discriminant analysis, the sensitivity and specificity of the technique for distinguishing patients with tumors from healthy controls and patients with cirrhosis was 100%/94% and 81%/71%, respectively. Discriminatory metabolites included glycine, trimethylamine-N-oxide, hippurate, citrate, creatinine, creatine, and carnitine. This metabolic profile bears similarity to profiles identified in the Nigerian cohort of subjects indicative of tumor effects on physiology, energy production, and aberrant chromosomal methylation. This is the first study to identify similarly altered urine metabolic profiles of hepatocellular carcinoma in two etiologically and ethnically distinct populations, suggesting that altered metabolism as a result of tumorogenesis is independent of these two factors.
Hepatocellular carcinoma (HCC) is the commonest primary hepatic malignancy worldwide. Current serum diagnostic biomarkers, such as alpha-fetoprotein, are expensive and insensitive in early tumor diagnosis. Urinary biomarkers differentiating HCC from chronic liver disease would be practical and widely applicable. Using an 11.7T nuclear magnetic resonance system, urine was analyzed from three well-matched subject groups, collected at Jos University Teaching Hospital (JUTH), Nigeria. Multivariate factor analyses were performed using principal components analysis (PCA) and partial least-squares discriminant analysis (PLS-DA). All patients were of Nigerian descent: 18 hepatitis B surface antigen (HBsAg)-positive patients with HCC, 10 HBsAg positive patients with cirrhosis, and 15 HBsAg negative healthy Nigerian controls. HCC patients were distinguished from healthy controls, and from the cirrhosis cohort, with sensitivity/specificity of 100%/93% and 89.5%/88.9%, respectively. Metabolites that most strongly contributed to the multivariate models were creatinine, carnitine, creatine and acetone. Urinary (1)H MRS with multivariate statistical analysis was able to differentiate patients with HCC from normal subjects and patients with cirrhosis. Creatinine, carnitine, creatine and acetone were identified as the most influential metabolites. These findings have identified candidate urinary HCC biomarkers which have potential to be developed as simple urinary screening tests for the clinic.
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