Gene Expression Profiling and Assessment of Vitamin D and Serotonin Pathway Variations in Patients With Irritable Bowel Syndrome.

BACKGROUND/AIMS: Irritable bowel syndrome (IBS) is a multifaceted disorder that afflicts millions of individuals worldwide. IBS is currently diagnosed based on the presence/duration of symptoms and systematic exclusion of other conditions. A more direct manner to identify IBS is needed to reduce healthcare costs and the time required for accurate diagnosis. The overarching objective of this work is to identify gene expression-based biological signatures and biomarkers of IBS. METHODS: Gene transcripts from 24 tissue biopsy samples were hybridized to microarrays for gene expression profiling. A combination of multiple statistical analyses was utilized to narrow the raw microarray data to the top 200 differentially expressed genes between IBS versus control subjects. In addition, quantitative polymerase chain reaction was employed for validation of the DNA microarray data. Gene ontology/pathway enrichment analysis was performed to investigate gene expression patterns in biochemical pathways. Finally, since vitamin D has been shown to modulate serotonin production in some models, the relationship between serum vitamin D and IBS was investigated via 25-hydroxyvitamin D (25[OH]D) chemiluminescence immunoassay. RESULTS: A total of 858 genetic features were identified with differential expression levels between IBS and asymptomatic populations. Gene ontology enrichment analysis revealed the serotonergic pathway as most prevalent among the differentially expressed genes. Further analysis via real-time polymerase chain reaction suggested that IBS patient-derived RNA exhibited lower levels of tryptophan hydroxylase-1 expression, the enzyme that catalyzes the rate-limiting step in serotonin biosynthesis. Finally, mean values for 25(OH)D were lower in IBS patients relative to non-IBS controls. CONCLUSIONS: Values for serum 25(OH)D concentrations exhibited a trend towards lower vitamin D levels within the IBS cohort. In addition, the expression of select IBS genetic biomarkers, including tryptophan hydroxylase 1, was modulated by vitamin D. Strikingly, the direction of gene regulation elicited by vitamin D in colonic cells is "opposite" to the gene expression profile observed in IBS patients, suggesting that vitamin D may help "reverse" the pathological direction of biomarker gene expression in IBS. Thus, our results intimate that IBS pathogenesis and pathophysiology may involve dysregulated serotonin production and/or vitamin D insufficiency.

One year recurrence of aberrant crypt foci.

Aberrant crypt foci (ACF) are putative precursors of colorectal adenomas and have been postulated as a potential biomarker for colorectal cancer. Few studies have followed subjects after ACF removal to monitor recurrence. Subjects enrolled in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial were recruited for a study of ACF. A standardized protocol using magnified endoscopy and mucosal staining with methylene blue was implemented to detect rectal ACF. After removal of all baseline ACF, subjects returned 1 year later and recurrent ACF were observed and biopsied. A total of 434 of 505 (86%) subjects observed at baseline returned for the year 1 exam. The mean number of ACF at year 1 was strongly correlated with the number at baseline; subjects with 0, 1, 2 to 3, 4 to 6, and 7+ ACF at baseline had a mean of 1.2, 1.4, 1.7, 3.0, and 5.5 ACF, respectively, at year 1. ACF prevalence and mean count at year 1 (61% and 1.93, respectively), were only slightly lower than the corresponding values at year 0 (69% and 2.25, respectively). The locations of ACF at year 1 and baseline were significantly correlated. Of 96 ACF assessed for histology, 70 (73%) were hyperplastic and none were dysplastic. After removal of ACF at baseline, ACF counts 1 year later were only slightly reduced and were significantly correlated with the baseline ACF count. The results of this study do not support a role for ACF in clinical practice.

Reliability and accuracy of the endoscopic appearance in the identification of aberrant crypt foci.

BACKGROUND: Aberrant crypt foci (ACF) have emerged as a putative precursor to colorectal adenoma, with potential use as a biomarker of colorectal cancer. However, there are wide differences in ACF prevalence, dysplasia, and histologic confirmation rates across studies. These differences may, in part, be because of variability in identification of endoscopic criteria. OBJECTIVE: To systematically evaluate the accuracy and reliability of various endoscopic criteria used to identify ACF when using magnification chromoendoscopy (MCE). DESIGN: Images obtained via MCE were shown to participating endoscopists who diagnosed them as ACF or not and who assessed them for the endoscopic characteristics used to identify ACF in the literature. MAIN OUTCOME MEASUREMENTS: The predictive ability of the endoscopic criteria (crypt number, staining, margin, crypt size, epithelial thickness, and lumen shape) for histologic confirmation of ACF, and their reliability across endoscopists. The accuracy of the examiners in identifying ACF that were histologically confirmed was also assessed. RESULTS: The interrater agreement rate for all except one of the endoscopic criteria (crypt number) was low and did not improve with training. None of the criteria could significantly predict histologic confirmation of ACF. Despite training exercises, accuracy of endoscopists to correctly identify a histologically proven ACF remained low. LIMITATIONS: Still images with x40 optical magnification were analyzed rather than real-time endoscopy. All ACF samples were hyperplastic; none were dysplastic. CONCLUSIONS: No endoscopic criteria evaluated by our study predicted histologic confirmation of ACF. MCE had low accuracy and poor reliability.

A multicenter study of prevalence and risk factors for aberrant crypt foci.

BACKGROUND & AIMS: Aberrant crypt foci (ACF) are the putative precursor of colorectal adenomas. However, there are limited data available on the prevalence and risk factors for ACF. METHODS: Subjects from the Prostate, Lung, Colorectal and Ovarian cancer screening trial were recruited for an ACF study, with subjects with adenoma history being oversampled. By using a standardized protocol of magnified chromoendoscopy with methylene blue staining (up to the middle rectal fold), ACF were photo-documented and removed for histologic evaluation. RESULTS: A total of 505 (66% male; 55% > or =70 y) subjects from 4 institutions were examined; 42% had no adenoma, 32% had nonadvanced distal adenoma, and 25% had advanced distal adenoma at the baseline Prostate, Lung, Colorectal and Ovarian cancer screening trial examination (8.2 years before ACF examination on average). A total of 68% of this population had 1 or more ACF, 43% had 1 to 3, 19% had 4 to 6, and 5% had 7 or more. Baseline adenoma status was not associated with ACF prevalence (range, 66%-69%) or mean number of ACF (range, 3.1-3.5). Of 143 endoscopic ACF examined histologically, 68.5% were confirmed to be ACF. In a logistic model, current (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.2-5.6) and former smoking (OR, 1.6; 95% CI, 1.1-2.5) were associated with higher ACF prevalence; a body mass index greater than 30 was associated with lower prevalence (OR, 0.53; 95% CI, 0.35-0.8). Age, sex, family history of colorectal cancer, and aspirin/nonsteroidal anti-inflammatory drug use were not associated significantly with ACF prevalence. CONCLUSIONS: ACF prevalence and number were not associated with adenoma history, and only 68.5% of endoscopic ACF were confirmed histologically. These results raise concern about the use of ACF as a surrogate marker of colorectal cancer risk.

The natural history of aberrant crypt foci.

BACKGROUND: Aberrant crypt foci (ACF) are the putative precursors to colorectal adenomas and may be useful as biomarkers. Knowledge of their natural history is essential to understanding their potential utility. OBJECTIVE: Our purpose was to examine ACF detection 1 year after initial observation. DESIGN: We conducted a multicenter study of ACF by using a standardized protocol. ACF in the rectum were assessed and subjects returned 1 year later to evaluate the natural history of the lesions. SETTING: Ancillary study to the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. RESULTS: Of 78 subjects enrolled, 64 (82%) returned for a repeat examination 1 year later. The mean age was 71 years, 70% were male, and 54% had a history of adenomatous polyps. At the initial examination, 66% of subjects had at least 1 ACF detected in the rectum, with a mean of 2.1 +/- 2.3 per person. One year later, 60% of these subjects had at least 1 of the original ACF reidentified, but only 43% of all ACF were reidentified. A total of 56% of subjects had new ACF identified. LIMITATIONS: These results are generated from the pilot phase. Improvements or change in technique over time could have influenced the results. CONCLUSIONS: A total of 60% of subjects who had ACF continued to have at least one ACF 1 year later, but less than half the specific ACF could be reidentified, and more than 50% of subjects had new ACF. These results imply a considerable dynamic to ACF detection over a 1-year period of observation.

Successful endoscopic treatment of mediastinal pseudocysts.

Mediastinal pseudocysts can pose a diagnostic and therapeutic challenge to the clinician and surgeon. Recognizing their presence and instituting appropriate therapy can reduce morbidity and mortality. This report describes unusual clinical features in a patient presenting with multiple mediastinal pseudocysts due to pancreatic duct leak secondary to pancreatic duct stenosis and an entrapment of a pancreatic duct stone. Successful endoscopic therapy averted the need for surgery.