Urinary NMR metabolomic profiles discriminate inflammatory bowel disease from healthy.

BACKGROUND AND AIMS: Inflammatory bowel disease, a chronic inflammation of the intestinal tract, presents in two variations, Ulcerative Colitis (UC) and Crohn's disease (CD). Given that treatment of CD differs from UC, a single test that provided strong diagnostic ability would offer great clinical value. Two previous studies have indicated that CD can be distinguished from UC, and that both can be distinguished from non-IBD-type gastrointestinal disease, based on urinary and faecal metabolite profiling. METHODS: Analysis of healthy as well as CD and UC patients attending an IBD clinic was performed. IBD patients were classified into two groups (CD or UC) based on chart review of clinical, endoscopic, and histological assessment. Urine samples were obtained and analyzed using nuclear magnetic resonance (NMR) spectroscopy combined with targeted profiling techniques, followed by univariate and multivariate statistical analysis. RESULTS: Based on urinary metabolomics, individuals with IBD could be differentiated from healthy. Major differences between IBD and healthy included TCA cycle intermediates, amino acids, and gut microflora metabolites. Comparison of CD and UC patients revealed discrimination, but removal of patients with the surgical intervention confounder revealed that CD could not be discriminated from UC. CONCLUSIONS: This study highlights the potential for metabolomics to distinguish IBD from the healthy state but shows that careful consideration must be given to establishing disease-representative cohorts that are free of confounding factors.

Time to recognize our fellow travellers.

It is increasingly apparent that human health is reliant on our fellow travellers, the innumerable microorganisms that inhabit our bodies. This realization has led to the concept of the superorganism, which suggests that shared metabolic and signalling pathways are crucial for optimal existence of both host and commensal microflora. This commentary focuses on implications of this paradigm for personalized medicine and therapeutics. Study of the microbiome, the collection of microorganisms inhabiting the body, may identify disease-associated microbial profiles with pathophysiological and diagnostic value. As with genomics, companies will emerge offering direct to consumer microbiome analysis. Probiotics can potentially modulate the superorganism for therapeutic benefit. However, the probiotics industry will need to undergo a transformation, with increased focus on stringent manufacturing guidelines and high-quality clinical trials. Ultimately, we suggest that healthcare will move beyond its prevailing focus on human physiology, and embrace the superorganism as a paradigm to understand disease.

Prevalence of genetic variants associated with inflammatory bowel disease in a healthy First Nations cohort.

BACKGROUND: Inflammatory bowel disease is the result of both genes and environment. Canadian First Nations people, despite living in a region with a high prevalence of inflammatory bowel disease, are relatively protected from this disease. We aimed to compare the carriage of genetic variants associated with inflammatory bowel disease in healthy First Nations and white people. METHODS: DNA was extracted from the venous blood of healthy First Nations (n = 340) and white (n = 285) participants from Manitoba. Genotyping was performed for 69 single nucleotide polymorphisms (SNPs) with known or suspected associations with inflammatory bowel disease. We compared the genotypes between groups by logistic regression, adjusting for multiple testing. We calculated a risk score for the NOD2 gene by adding the number of risk alleles at three important NOD2 SNPs (G908R, R702W and 3020insC). RESULTS: We found genetic variation between white and First Nations participants at 45 of 69 SNPs. Notably, carriage of the ATG16L1 T300A mutation was lower in First Nations participants (p = 4.1 × 10(-30)). Cumulative carriage of important NOD2 variants was significantly lower among First Nations participants (3.9% v. 15.2%; p < 0.0001 for risk score) than among white participants. Risk variants in IL23R (p = 0.014) and IL12B (p = 1.2 × 10(-16)), among others, were more prevalent among First Nations participants than among white participants. INTERPRETATION: The low prevalence of variants associated with bacterial processing and handling in First Nations people may explain their relative protection from inflammatory bowel disease. Increased carriage of a number of risk variants, for example in the interleukin-23/Th17 pathway, is especially intriguing given their importance in other inflammatory diseases of high incidence in First Nations populations.

Pattern recognition receptor and autophagy gene variants are associated with development of antimicrobial antibodies in Crohn's disease.

BACKGROUND: We sought to investigate whether variants in genes involved in bacterial sensing and autophagy (NOD2, TLR5, IRGM, ATG16L1) and the interleukin-23 signaling pathway (IL12B, IL23R, STAT3) were associated with development of antimicrobial antibodies in patients with Crohn's disease (CD). METHODS: A cohort of 616 CD patients from a tertiary referral hospital (Mount Sinai Hospital, Toronto) was evaluated. DNA was tested for three CD-associated NOD2 variants (3020insC, G908R, R702W), variants in IRGM, ATG16L1, IL12B, IL23R, STAT3, and a TLR5-stop mutation. Serum was analyzed by enzyme-linked immunosorbent assay (ELISA) for anti-Saccharomyces cerevisiae (ASCA) IgG and IgA, anti-outer membrane porin C (anti-ompC), anti-Cbir1 flagellin, and anti-Pseudomonas fluorescens (anti-I2). RESULTS: NOD2 3020insC was associated with cumulative seroreactivity by quartile sum (P = 0.003) and number of positive antibodies (P = 0.02). NOD2 G908R was also associated with quartile sum (P = 0.05). Increased ASCA seropositivity was associated with NOD2 3020insC (odds ratio [OR] = 1.9, P = 0.02) and G908R (OR = 1.8, P = 0.05), and ATG16L1 T300A (OR = 1.4, P = 0.01) variants; ASCA-positive patients had an increased cumulative number of NOD2 3020insC and ATG16L1 T300A variants (P = 0.007). TLR5-stop mutation abrogated development of anti-flagellin in a dominant-negative fashion (OR = 0.5, P = 0.009). The IRGM CD risk variant was associated with increased anti-flagellin seropositivity (OR = 1.5, P = 0.03). IL12B, IL23R, and STAT3 variants did not contribute to development of antimicrobial antibodies. CONCLUSIONS: Variants in innate immune genes involved in pattern recognition and autophagy but not the interleukin-23 signaling pathway influence antimicrobial seroreactivity in CD. In particular, the additive effect of NOD2 3020insC and ATG16L1 T300A suggests a role for autophagy in development of ASCA.

Urinary metabolic profiles of inflammatory bowel disease in interleukin-10 gene-deficient mice.

Inflammatory bowel disease (IBD) is a chronic debilitating disorder that is thought to have both genetic and environmental contributors. Commensal microflora have been shown to play a key part in the disease process. Metabolomics, the study of large numbers of small molecule metabolites, has demonstrated that disease and/or changes in gut microbial composition modulate mammalian urine metabolite fingerprints. The aim of this project was to associate the development of IBD with specific changes in a mouse urinary metabolic fingerprint. Interleukin-10 (IL-10) gene-deficient mice were raised alongside age-matched 129/SvEv controls in conventional housing. Urine samples (22 h) were collected at ages 4, 6, 8, 12, 16, and 20 weeks. Metabolite concentrations were derived from analysis of nuclear magnetic resonance spectra, and both multivariate and two-way analysis of variance (ANOVA) statistical techniques were applied to the resulting data. Principal component analysis and partial least-squares-discriminant analysis of urine derived from the control and IL-10 gene-deficient mice revealed that while both groups initially had similar metabolic profiles, they diverged substantially with the onset of IBD as assessed through external phenotypic changes. Several metabolites, including trimethylamine (TMA) and fucose, changed dramatically in the IL-10 gene-deficient mice following 8 weeks of age, concomitant with the known timeline for development of severe histological injury. This study illustrates that metabolomics is effective at distinguishing IBD using urinary metabolite profiles.

Estimation of pancreas weight from donor variables.

Previous studies have identified several donor factors affecting the outcome of islet isolation. Pancreas weight has not been considered as a donor selection criterion, because a value cannot be obtained prior to organ procurement. However, a larger pancreas will likely contain a higher number of islets. Therefore, the prediction of pancreas weight would be helpful in donor selection, benefiting cost and efficiency of the islet isolation laboratory. The purpose of this study was to investigate normal pancreas weight in cadaveric donors and identify pancreas weight predictors from demographic data of cadaveric organ donors. We retrospectively analyzed data on pancreas weight from 354 cadaveric donors with respect to gender, age, body weight, body height, body mass index (BMI), and body surface area (BSA). In men, pancreas weight correlated more closely with body weight than with age, height, or BMI. BSA was as strong a correlate of pancreas weight as body weight. In women, pancreas weight had a similar pattern of relationships, with generally lower correlation coefficients. On the basis of the observation of gender-specific pancreas weight difference in elderly donors, stepwise multiple linear regression analyses were conducted separately for younger (< or =40 years) and elderly (> or =41 years) donors. In younger donors, body weight and age were the major predictors of pancreas weight [pancreas weight (g) = 4.355 + 0.742 x body weight (kg) + 0.837 x age (years) (R2 = 0.564, p < 0.001)]. In contrast, pancreas weight of elderly donors was best predicted by BSA and gender [pancreas weight (g) = -17.624 + 60.036 x BSA (m2) - 7.152 x gender (R2 = 0.372, p < 0.001; "gender": 1 = female, 0 = male)]. Pancreas weight was found to be positively associated with pre- and postpurification islet yields. These formulae should contribute to the estimation of pancreas weight, and thus improve donor selection for islet isolation and transplantation.