Minimal Gluten Exposure Alters Urinary Volatile Organic Compounds in Stable Coeliac Disease.

Coeliac disease (CD) patients are distinguishable from healthy individuals via urinary volatile organic compounds (VOCs) analysis. We exposed 20 stable CD patients on gluten-free diet (GFDs) to a 14-day, 3 g/day gluten challenge (GCh), and assessed urinary VOC changes. A control cohort of 20 patients continued on GFD. Urine samples from Days 0, 7, 14, 28 and 56 were analysed using Lonestar FAIMS and Markes Gas Chromatography-Time of Flight-Mass Spectrometer (GC-TOF-MS). VOC signatures on D (day) 7-56 were compared with D0. Statistical analysis was performed using R. In GCh patients, FAIMS revealed significant VOC differences for all time points compared to D0. GC-TOF-MS revealed significant changes at D7 and D14 only. In control samples, FAIMS revealed significant differences at D7 only. GC-TOF-MS detected no significant differences. Chemical analysis via GC-MS-TOF revealed 12 chemicals with significantly altered intensities at D7 vs. D0 for GCh patients. The alterations persisted for six chemicals at D14 and one (N-methyltaurine) remained altered after D14. This low-dose, short-duration challenge was well tolerated. FAIMS and GC-TOF-MS detected VOC signature changes in CD patients when undergoing a minimal GCh. These findings suggest urinary VOCs could have a role in monitoring dietary compliance in CD patients.

Pre-analytical and analytical variables that influence urinary volatile organic compound measurements.

There has been rapidly accelerating interest in the utilization of volatile organic compounds (VOCs) as non-invasive methods for rapid point-of-care medical diagnostics. There is widespread variation in analytical methods and protocols, with little understanding of the effects of sample storage on VOC profiles. This study aimed to determine the effects on VOC profiles of different storage times, at room temperature, prior to freezing, of sealed urine samples from healthy individuals. Analysis using Field Asymmetric Ion Motility Spectrometry (FAIMS) determined the alterations in VOC and total ion count profiles as a result of increasing room temperature storage times. Results indicated that increasing exposure time to room temperature prior to freezing had a threefold effect. Firstly, increased urinary VOC profile variability, with a plateau phase between 12 and 48 hours, before further degradation. Secondly, an increase in total ion count with time exposed to room temperature. Finally, a deterioration in VOCs with each sample run during the analysis process. This provides new insight into the effect of storage of urine samples for VOC analysis using FAIMS technology. Results of this study provide a recommendation for a 12-hour maximum duration at room temperature prior to storage.

An assessment of candidate genes to assist prognosis in gastric cancer.

BACKGROUND: Gastric cancer (GC) is the fourth commonest cancer worldwide, with the second highest mortality rate. Its poor mortality is linked to delayed presentation. There is a drive towards non-invasive biomarker screening and monitoring of many different types of cancer, although with limited success so far. We aimed to determine if any genes from a 32-gene panel could be used to determine GC prognosis. METHODS: We carried out a retrospective study on the expression of 32 genes, selected for their proven or potential links to GC, on historic formalin fixed paraffin-embedded (FFPE) GC specimens from our unit. Gene expression was measured using quantitative nuclease protection assays (qNPA) technology. Following statistical analysis of the results, immunohistochemical staining for eight genes, both discriminating and non-discriminating, was conducted in seven age and sex matched non-metastatic: metastatic GC pairings. The stained samples were reviewed by two blinded consultant histopathologists. RESULTS: Multivariate Cox analysis of the gene expression data revealed metastatic status, age, sex and five genes appeared to influence GC survival. Genes negatively influencing survival included BCAS1, P53 and HSP90AA1 (relative risks 2.20, 3.73 and 7.53 respectively). Genes conveying survival benefit included CASP3 and TERT (relative risks 0.10 and 0.24 respectively). Immunohistochemical staining of seven age and sex matched non-metastatic: metastatic pairs revealed no association between gene expression and protein expression. CONCLUSIONS: Our study found several genes whose expression may affect GC prognosis. However, immunohistochemical analysis revealed no association between gene expression and protein expression. It remains to be determined whether gene expression or protein expression are reliable means of assessing GC prognosis.

A Randomized, Double-blind, Placebo-controlled, Parallel-group, Pilot Study of Cannabidiol-rich Botanical Extract in the Symptomatic Treatment of Ulcerative Colitis.

Background: Cannabidiol (CBD) exhibits anti-inflammatory properties that could improve disease activity in inflammatory bowel disease. This proof-of-concept study assessed efficacy, safety and tolerability of CBD-rich botanical extract in ulcerative colitis (UC) patients. Methods: Patients aged 18 years or older, with left-sided or extensive UC, Mayo scores of 4-10 (endoscopy scores ≥1), and on stable 5-aminosalicylic acid dosing, were randomized to 10-weeks' CBD-rich botanical extract or placebo capsules. The primary endpoint was the percentage of patients in remission after treatment. Statistical testing was 2-sided, using a 10% significance level. Results: Patients were less tolerant of CBD-rich botanical extract compared with placebo, taking on average one-third fewer capsules, and having more compliance-related protocol deviations (principally insufficient exposure), prompting identification of a per protocol (PP) analysis set. The primary endpoint was negative; end of treatment remission rates were similar for CBD-rich botanical extract (28%) and placebo (26%). However, PP analysis of total and partial Mayo scores favoured CBD-rich botanical extract (P = 0.068 and P = 0.038, respectively). Additionally, PP analyses of the more subjective physician's global assessment of illness severity, subject global impression of change, and patient-reported quality-of-life outcomes were improved for patients taking CBD-rich botanical extract (P = 0.069, P = 0.003, and P = 0.065, respectively). Adverse events (AEs) were predominantly mild/moderate with many in the CBD-rich botanical extract group potentially attributable to the ∆9-tetrahydrocannabinol content. A greater proportion of gastrointestinal-related AEs, indicative of UC worsening, was seen on placebo. Conclusion: Although the primary endpoint was not reached, several signals suggest CBD-rich botanical extract may be beneficial for symptomatic treatment of UC.

Mechanisms of triglyceride metabolism in patients with bile acid diarrhea.

Bile acids (BAs) are essential for the absorption of lipids. BA synthesis is inhibited through intestinal farnesoid X receptor (FXR) activity. BA sequestration is known to influence BA metabolism and control serum lipid concentrations. Animal data has demonstrated a regulatory role for the FXR in triglyceride metabolism. FXR inhibits hepatic lipogenesis by inhibiting the expression of sterol regulatory element binding protein 1c via small heterodimer primer activity. Conversely, FXR promotes free fatty acids oxidation by inducing the expression of peroxisome proliferator-activated receptor α. FXR can reduce the expression of microsomal triglyceride transfer protein, which regulates the assembly of very low-density lipoproteins (VLDL). FXR activation in turn promotes the clearance of circulating triglycerides by inducing apolipoprotein C-II, very low-density lipoproteins receptor (VLDL-R) and the expression of Syndecan-1 together with the repression of apolipoprotein C-III, which increases lipoprotein lipase activity. There is currently minimal clinical data on triglyceride metabolism in patients with bile acid diarrhoea (BAD). Emerging data suggests that a third of patients with BAD have hypertriglyceridemia. Further research is required to establish the risk of hypertriglyceridaemia in patients with BAD and elicit the mechanisms behind this, allowing for targeted treatment.

Synchronous Upper and Lower Gastrointestinal Mucosa-Associated Lymphoid Tissue Lymphomas.

Mucosa-associated lymphoid tissue lymphoma (MALToma) is a subtype of B-cell non-Hodgkin's lymphoma, comprising ∼17% of all gastrointestinal (GI) tract lymphomas. It is associated with chronic inflammation and autoimmunity, for example Helicobacter pylori gastritis and Sjogren's syndrome, respectively. Approximately 50% of GI MALTomas occur in the stomach, with small bowel and colonic lesions being less frequent. Synchronous upper and lower GI MALTomas occur rarely, with few cases reported. We present the case of a 73-year-old patient who presented with change in bowel habit and was found to have synchronous multifocal upper and lower GI MALTomas, which did not respond to H. pylori cure or to rituximab therapy, but did respond to a combination of surgery and chemotherapy with rituximab and bendamustine.

Clinical outcomes at 12†months and risk of inflammatory bowel disease in patients with an intermediate raised fecal calprotectin: a 'real-world' view.

OBJECTIVES: A recent systematic review confirmed the usefulness of fecal calprotectin (FC) in distinguishing organic (inflammatory bowel disease (IBD)) from non-organic gastrointestinal disease (irritable bowel syndrome (IBS)). FC levels <50 µg/g have a negative predictive value >92% to exclude organic gastrointestinal (GI) disease. Levels >250 µg/g correlate with endoscopic IBD disease activity; sensitivity 90%. We aimed to determine clinical outcomes in intermediate raised FC results (50-250 µg/g). SETTING: Primary care general practices in Coventry and Warwickshire, and 3 secondary care hospitals. PARTICIPANTS: 443 FC results in adults (>16 years old) were reviewed from July 2012 to October 2013. Clinical data was collected from hospital databases and general practitioners. Long-term clinical data was available in 41 patients (out of 48). PRIMARY AND SECONDARY OUTCOME MEASURES: The number of new diagnoses of IBD, IBS and other diagnoses for the intermediate group. The number referred and discharged from secondary care. RESULTS: A new IBD diagnosis was made in 19% (n=8) of intermediate results (1% of normal and 38% of raised results). 5% (n=2) of intermediate results had known IBD in remission. A new IBS diagnosis was made in 27% (n=11) of intermediate results, while 34% (n=14) remained undiagnosed, although 8 of these were not referred to secondary care. CONCLUSIONS: FC testing remains useful in aiding diagnosis of organic GI conditions. However, unlike negative and strongly positive FC results, intermediate FC results lead to a mixture of diagnoses. The OR of a new diagnosis of IBD for an intermediate result compared to normal FC result was 26.6, while an intermediate FC result gave an OR of 0.54 for a new IBS diagnosis compared to normal FC. For intermediate FC results, 1 in 3 patients remained in secondary care after 12 months with an OR of 3.6 compared to a normal FC result.

A systematic review of the role of DNA methylation on inflammatory genes in ulcerative colitis.

BACKGROUND: Ulcerative colitis (UC) is an idiopathic disease of the large intestine with evidence pointing to the role of epigenetic changes. METHODS: Searches were performed in three databases (EMBASE, MEDLINE and Web of Science), following PRISMA protocol. DNA methylation was the only epigenetic mechanism affecting genes linked to inflammatory response in UC. RESULTS: A total of 25 differentially methylated inflammatory genes were identified. Hypermethylation of miR-1247 significantly correlates (p = 0.0006) with refractory UC while PAR2 hypermethylation correlates (p = 0.007) with corticosteroid dependence. CONCLUSION: Evidence points to a step-wise increase in methylation status of the genome between a healthy colon, quiescent UC and when inflamed. Inflammatory genes (which are aberrantly methylated), have also been implicated in cancer development in UC.

Variation in Gas and Volatile Compound Emissions from Human Urine as It Ages, Measured by an Electronic Nose.

The medical profession is becoming ever more interested in the use of gas-phase biomarkers for disease identification and monitoring. This is due in part to its rapid analysis time and low test cost, which makes it attractive for many different clinical arenas. One technology that is showing promise for analyzing these gas-phase biomarkers is the electronic nose--an instrument designed to replicate the biological olfactory system. Of the possible biological media available to "sniff", urine is becoming ever more important as it is easy to collect and to store for batch testing. However, this raises the question of sample storage shelf-life, even at -80 °C. Here we investigated the effect of storage time (years) on stability and reproducibility of total gas/vapour emissions from urine samples. Urine samples from 87 patients with Type 2 Diabetes Mellitus were collected over a four-year period and stored at -80 °C. These samples were then analyzed using FAIMS (field-asymmetric ion mobility spectrometry--a type of electronic nose). It was discovered that gas emissions (concentration and diversity) reduced over time. However, there was less variation in the initial nine months of storage with greater uniformity and stability of concentrations together with tighter clustering of the total number of chemicals released. This suggests that nine months could be considered a general guide to a sample shelf-life.

Non-invasive exhaled volatile organic biomarker analysis to detect inflammatory bowel disease (IBD).

INTRODUCTION: Early inflammatory bowel disease (IBD) diagnosis remains a clinical challenge. Volatile organic compounds (VOCs) have shown distinct patterns in Crohn's disease (CD) and ulcerative colitis (UC). VOC production, reflecting gut fermentome metabolites, is perturbed in IBD. VOC sampling is non-invasive, with various compounds identified from faecal, breath and urine samples. This study aimed to determine if FAIMS (field asymmetric ion mobility spectroscopy) analysis of exhaled VOCs could distinguish IBD from controls. METHODS: Seventy-six subjects were recruited, 54 established IBD (25 CD, 29 UC) and 22 healthy controls. End expiratory breath was captured using a Warwick device and analysed by FAIMS. Data were pre-processed using wavelet transformation, and classification performed in a 10-fold cross-validation. Feature selection was performed using Wilcoxon rank sum test, and sparse logistic regression gave class predictions, to calculate sensitivity and specificity. RESULTS: FAIMS breath VOC analysis showed clear separation of IBD from controls, sensitivity: 0.74 (0.65-0.82), specificity: 0.75 (0.53-0.90), AUROC: 0.82 (0.74-0.89), p-value 6.2×10(-7). IBD subgroup analysis distinguished UC from CD: sensitivity of 0.67 (0.54-0.79), specificity: 0.67 (0.54-0.79), AUROC: 0.70 (0.60-0.80), p-value 9.23×10(-4). CONCLUSION: This confirms the utility of exhaled VOC analysis to distinguish IBD from healthy controls, and UC from CD. It conforms to other studies using different technology, whilst affirming exhaled VOCs as biomarkers for diagnosing IBD.

Mercaptopurine versus placebo to prevent recurrence of Crohn's disease after surgical resection (TOPPIC): a multicentre, double-blind, randomised controlled trial.

BACKGROUND: Up to 60% of patients with Crohn's disease need intestinal resection within the first 10 years of diagnosis, and postoperative recurrence is common. We investigated whether mercaptopurine can prevent or delay postoperative clinical recurrence of Crohn's disease. METHODS: We did a randomised, placebo-controlled, double-blind trial at 29 UK secondary and tertiary hospitals of patients (aged >16 years in Scotland or >18 years in England and Wales) who had a confirmed diagnosis of Crohn's disease and had undergone intestinal resection. Patients were randomly assigned (1:1) by a computer-generated web-based randomisation system to oral daily mercaptopurine at a dose of 1 mg/kg bodyweight rounded to the nearest 25 mg or placebo; patients with low thiopurine methyltransferase activity received half the normal dose. Patients and their carers and physicians were masked to the treatment allocation. Patients were followed up for 3 years. The primary endpoint was clinical recurrence of Crohn's disease (Crohn's Disease Activity Index >150 plus 100-point increase in score) and the need for anti-inflammatory rescue treatment or primary surgical intervention. Primary and safety analyses were by intention to treat. Subgroup analyses by smoking status, previous thiopurines, previous infliximab or methotrexate, previous surgery, duration of disease, or age at diagnosis were also done. This trial is registered with the International Standard Randomised Controlled Trial Register (ISRCTN89489788) and the European Clinical Trials Database (EudraCT number 2006-005800-15). FINDINGS: Between June 6, 2008, and April 23, 2012, 240 patients with Crohn's disease were randomly assigned: 128 to mercaptopurine and 112 to placebo. All patients received at least one dose of study drug, and no randomly assigned patients were excluded from the analysis. 16 (13%) of patients in the mercaptopurine group versus 26 (23%) patients in the placebo group had a clinical recurrence of Crohn's disease and needed anti-inflammatory rescue treatment or primary surgical intervention (adjusted hazard ratio [HR] 0·54, 95% CI 0·27-1·06; p=0·07; unadjusted HR 0·53, 95% CI 0·28-0·99; p=0·046). In a subgroup analysis, three (10%) of 29 smokers in the mercaptopurine group and 12 (46%) of 26 in the placebo group had a clinical recurrence that needed treatment (HR 0·13, 95% CI 0·04-0·46), compared with 13 (13%) of 99 non-smokers in the mercaptopurine group and 14 (16%) of 86 in the placebo group (0·90, 0·42-1·94; pinteraction=0·018). The effect of mercaptopurine did not significantly differ from placebo for any of the other planned subgroup analyses (previous thiopurines, previous infliximab or methotrexate, previous surgery, duration of disease, or age at diagnosis). The incidence and types of adverse events were similar in the mercaptopurine and placebo groups. One patient on placebo died of ischaemic heart disease. Adverse events caused discontinuation of treatment in 39 (30%) of 128 patients in the mercaptopurine group versus 41 (37%) of 112 in the placebo group. INTERPRETATION: Mercaptopurine is effective in preventing postoperative clinical recurrence of Crohn's disease, but only in patients who are smokers. Thus, in smokers, thiopurine treatment seems to be justified in the postoperative period, although smoking cessation should be strongly encouraged given that smoking increases the risk of recurrence. FUNDING: Medical Research Council.

Non-invasive distinction of non-alcoholic fatty liver disease using urinary volatile organic compound analysis: early results.

BACKGROUND & AIMS: Non-Alcoholic Fatty Liver Disease (NAFLD) is the commonest cause of chronic liver disease in the western world. Current diagnostic methods including Fibroscan have limitations, thus there is a need for more robust non-invasive screening methods. The gut microbiome is altered in several gastrointestinal and hepatic disorders resulting in altered, unique gut fermentation patterns, detectable by analysis of volatile organic compounds (VOCs) in urine, breath and faeces. We performed a proof of principle pilot study to determine if progressive fatty liver disease produced an altered urinary VOC pattern; specifically NAFLD and Non-Alcoholic Steatohepatitis (NASH). METHODS: 34 patients were recruited: 8 NASH cirrhotics (NASH-C); 7 non-cirrhotic NASH; 4 NAFLD and 15 controls. Urine was collected and stored frozen. For assay, the samples were defrosted and aliquoted into vials, which were heated to 40±0.1°C and the headspace analyzed by FAIMS (Field Asymmetric Ion Mobility Spectroscopy). A previously used data processing pipeline employing a Random Forrest classification algorithm and using a 10 fold cross validation method was applied. RESULTS: Urinary VOC results demonstrated sensitivity of 0.58 (0.33 - 0.88), but specificity of 0.93 (0.68 - 1.00) and an Area Under Curve (AUC) 0.73 (0.55 - 0.90) to distinguish between liver disease and controls. However, NASH/NASH-C was separated from the NAFLD/controls with a sensitivity of 0.73 (0.45 - 0.92), specificity of 0.79 (0.54 - 0.94) and AUC of 0.79 (0.64 - 0.95), respectively. CONCLUSIONS: This pilot study suggests that urinary VOCs detection may offer the potential for early non-invasive characterisation of liver disease using 'smell prints' to distinguish between NASH and NAFLD.

Polymorphisms near TBX5 and GDF7 are associated with increased risk for Barrett's esophagus.

BACKGROUND & AIMS: Barrett's esophagus (BE) increases the risk of esophageal adenocarcinoma (EAC). We found the risk to be BE has been associated with single nucleotide polymorphisms (SNPs) on chromosome 6p21 (within the HLA region) and on 16q23, where the closest protein-coding gene is FOXF1. Subsequently, the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON) identified risk loci for BE and esophageal adenocarcinoma near CRTC1 and BARX1, and within 100 kb of FOXP1. We aimed to identify further SNPs that increased BE risk and to validate previously reported associations. METHODS: We performed a genome-wide association study (GWAS) to identify variants associated with BE and further analyzed promising variants identified by BEACON by genotyping 10,158 patients with BE and 21,062 controls. RESULTS: We identified 2 SNPs not previously associated with BE: rs3072 (2p24.1; odds ratio [OR] = 1.14; 95% CI: 1.09-1.18; P = 1.8 × 10(-11)) and rs2701108 (12q24.21; OR = 0.90; 95% CI: 0.86-0.93; P = 7.5 × 10(-9)). The closest protein-coding genes were respectively GDF7 (rs3072), which encodes a ligand in the bone morphogenetic protein pathway, and TBX5 (rs2701108), which encodes a transcription factor that regulates esophageal and cardiac development. Our data also supported in BE cases 3 risk SNPs identified by BEACON (rs2687201, rs11789015, and rs10423674). Meta-analysis of all data identified another SNP associated with BE and esophageal adenocarcinoma: rs3784262, within ALDH1A2 (OR = 0.90; 95% CI: 0.87-0.93; P = 3.72 × 10(-9)). CONCLUSIONS: We identified 2 loci associated with risk of BE and provided data to support a further locus. The genes we found to be associated with risk for BE encode transcription factors involved in thoracic, diaphragmatic, and esophageal development or proteins involved in the inflammatory response.

Detection of colorectal cancer (CRC) by urinary volatile organic compound analysis.

Colorectal cancer (CRC) is a leading cause of cancer related death in Europe and the USA. There is no universally accepted effective non-invasive screening test for CRC. Guaiac based faecal occult blood (gFOB) testing has largely been superseded by Faecal Immunochemical testing (FIT), but sensitivity still remains poor. The uptake of population based FOBt testing in the UK is also low at around 50%. The detection of volatile organic compounds (VOCs) signature(s) for many cancer subtypes is receiving increasing interest using a variety of gas phase analytical instruments. One such example is FAIMS (Field Asymmetric Ion Mobility Spectrometer). FAIMS is able to identify Inflammatory Bowel disease (IBD) patients by analysing shifts in VOCs patterns in both urine and faeces. This study extends this concept to determine whether CRC patients can be identified through non-invasive analysis of urine, using FAIMS. 133 patients were recruited; 83 CRC patients and 50 healthy controls. Urine was collected at the time of CRC diagnosis and headspace analysis undertaken using a FAIMS instrument (Owlstone, Lonestar, UK). Data was processed using Fisher Discriminant Analysis (FDA) after feature extraction from the raw data. FAIMS analyses demonstrated that the VOC profiles of CRC patients were tightly clustered and could be distinguished from healthy controls. Sensitivity and specificity for CRC detection with FAIMS were 88% and 60% respectively. This study suggests that VOC signatures emanating from urine can be detected in patients with CRC using ion mobility spectroscopy technology (FAIMS) with potential as a novel screening tool.

Differentiating coeliac disease from irritable bowel syndrome by urinary volatile organic compound analysis--a pilot study.

Coeliac disease (CD), a T-cell-mediated gluten sensitive enteropathy, affects ∼ 1% of the UK population and can present with wide ranging clinical features, often being mistaken for Irritable Bowel Syndrome (IBS). Heightened clinical awareness and serological screening identifies those with potential coeliac disease; the diagnosis is confirmed with duodenal biopsies, and symptom improvement with a gluten-free diet. Limitations to diagnosis are false negative serology and reluctance to undergo biopsy. The gut microbiome is altered in several gastrointestinal disorders, causing altered gut fermentation patterns recognisable by volatile organic compounds (VOC) analysis in urine, breath and faeces. We aimed to determine if CD alters the urinary VOC pattern, distinguishing it from IBS. 47 patients were recruited, 27 with established CD, on gluten free diets, and 20 with diarrhoea-predominant IBS (D-IBS). Collected urine was stored frozen in 10 ml aliquots. For assay, the specimens were heated to 40 ± 0.1°C and the headspace analysed by Field Asymmetric Ion Mobility Spectrometry (FAIMS). Machine learning algorithms were used for statistical evaluation. Samples were also analysed using Gas chromatography and mass spectroscopy (GC-MS). Sparse logistic regression showed that FAIMS distinguishes VOCs in CD vs D-IBS with ROC curve AUC of 0.91 (0.83-0.99), sensitivity and specificity of 85% respectively. GCMS showed a unique peak at 4'67 found only in CD, not D-IBS, which correlated with the compound 1,3,5,7 cyclooctatetraene. This study suggests that FAIMS offers a novel, non-invasive approach to identify those with possible CD, and distinguishes from D-IBS. It offers the potential for monitoring compliance with a gluten-free diet at home. The presence of cyclooctatetraene in CD specimens will need further validation.

Application of a novel tool for diagnosing bile acid diarrhoea.

Bile acid diarrhoea (BAD) is a common disease that requires expensive imaging to diagnose. We have tested the efficacy of a new method to identify BAD, based on the detection of differences in volatile organic compounds (VOC) in urine headspace of BAD vs. ulcerative colitis and healthy controls. A total of 110 patients were recruited; 23 with BAD, 42 with ulcerative colitis (UC) and 45 controls. Patients with BAD also received standard imaging (Se75HCAT) for confirmation. Urine samples were collected and the headspace analysed using an AlphaMOS Fox 4000 electronic nose in combination with an Owlstone Lonestar Field Asymmetric Ion Mobility Spectrometer (FAIMS). A subset was also tested by gas chromatography, mass spectrometry (GCMS). Linear Discriminant Analysis (LDA) was used to explore both the electronic nose and FAIMS data. LDA showed statistical differences between the groups, with reclassification success rates (using an n-1 approach) at typically 83%. GCMS experiments confirmed these results and showed that patients with BAD had two chemical compounds, 2-propanol and acetamide, that were either not present or were in much reduced quantities in the ulcerative colitis and control samples. We believe that this work may lead to a new tool to diagnose BAD, which is cheaper, quicker and easier that current methods.

A novel tool for noninvasive diagnosis and tracking of patients with inflammatory bowel disease.

BACKGROUND: The pathogenesis of inflammatory bowel disease (IBD) involves the role of bacteria. These bacteria ferment nonstarch polysaccharides in the colon producing a fermentation profile that through altered gut permeability can be traced in urine. We proposed to track the resultant volatile organic compounds or gases that emanate from urine using noninvasive real-time tools, specifically by electronic nose and Field Asymmetric Ion Mobility Spectrometer (FAIMS) instruments. The aim of this study was to determine the utility of electronic nose and FAIMS instruments to detect and track the fermentation profile of patients with IBD. METHODS: Sixty-two individuals were recruited, 48 individuals with IBD (24 with Crohn's disease and ulcerative colitis, respectively) and 14 controls. The disease activity was recorded, and urine samples were collected. The headspace (the air above the sample) was analyzed using the electronic nose and FAIMS instruments. RESULTS: Electronic nose data analysis was conducted through (1) Principal Component Analysis (data were analyzed together without previous categorization); and (2) Discriminant Function Analysis (samples were precategorized [clinical groups]). The FAIMS data were processed by Fisher's Discriminant Analysis (precategorized [clinical groups]). Both technologies consistently showed the ability to separate those with IBD and controls with a >75% accuracy; P < 0.001. In a smaller subgroup (n = 24), we also demonstrated that the electronic nose and FAIMS instruments can distinguish between active disease and those in remission. CONCLUSIONS: The fermentation profile or fermentome is disparate in those with IBD compared with controls--a reflection of the bacterial diversity in health and disease. This profile also changes (and was tracked) as the disease is induced into remission. Thus, the electronic nose and FAIMS instruments offer the potential of a noninvasive real-time diagnostic tool for point of care clinical use.

Selective measurement of anti-tTG antibodies in coeliac disease and IgA deficiency: an alternative pathway.

OBJECTIVE: To determine the ability of selective antibody testing to screen for coeliac disease in the presence of IgA deficiency and to define the sensitivity of a pathway using this method. METHOD: All IgA and IgG anti-tTG tests performed at our centre between January 2008 and December 2009, using the Immunocap 250 analyser, were retrospectively reviewed. Positive results were correlated with histology. Results were used to validate our diagnostic pathway. RESULTS: 12 289 consecutive serological tests were reviewed. IgA deficient patients gave either an 'error' reading or very low response on the Immunocap 250 analyser. Subsequent testing of this sub-group demonstrated raised IgG anti-tTG antibodies in those with histologically proven coeliac disease. CONCLUSIONS: Using our antibody screening pathway, which involves the selective use of IgG anti-tTG, sensitivity increased from 87% to 92% in those with IgA deficiency. Adoption of this pathway for coeliac screening would negate the routine screening of immunoglobulin levels, with resultant cost saving.