Folic Acid Supplementation in Postpolypectomy Patients in a Randomized Controlled Trial Increases Tissue Folate Concentrations and Reduces Aberrant DNA Biomarkers in Colonic Tissues Adjacent to the Former Polyp Site.

BACKGROUND: Low folate status is associated with an increased risk of colorectal carcinogenesis. Optimal folate status may be genoprotective by preventing uracil misincorporation into DNA and DNA hypomethylation. Adenomatous polyps have low folate status compared with normal colonic mucosa, and they are surrounded by histologically normal mucosa that also is of low folate status. OBJECTIVE: In a randomized controlled trial conducted at a single Dublin hospital between April 2002 and March 2004, we assessed the effect of folic acid supplementation on tissue folate, uracil misincorporation into DNA, and global DNA hypomethylation in colonocytes isolated from sites of adenomatous polyps and from histologically normal tissue adjacent and 10-15 cm distal to them. METHODS: Twenty patients with adenomatous polyps on initial colonoscopy and polypectomy were randomly assigned to receive either 600 µg folic acid/d [n = 12, 38% men, mean age 64.3 y, and body mass index (BMI, in kg/m(2)) 26.6] or placebo (n = 8, 50% men, mean age 68.4 y, and BMI 27.2) for 6 mo, and then repeat the colonoscopy. Blood and colonocyte tissue folate concentrations were measured with the use of a microbiological assay. Uracil misincorporation and global DNA hypomethylation were measured in colonocytes with the use of modified comet assays. RESULTS: Over time, folic acid supplementation, compared with placebo, increased tissue folate (mean ± SEM) from 15.6 ± 2.62 pg/10(5) cells to 18.1 ± 2.12 pg/10(5) cells (P < 0.001) and decreased the global DNA hypomethylation ratio from 1.7 ± 0.1 to 1.0 ± 0.1 (P < 0.001). The uracil misincorporation ratio decreased by 0.5 ± 0.1 for the site adjacent to the polyp over time (P = 0.05). CONCLUSION: A response to folic acid supplementation, which increased colonocyte folate and improved folate-related DNA biomarkers of cancer risk, was seen in the participants studied. Exploratory analysis points toward the area formerly adjacent to polyps as possibly driving the response. That these areas persist after polypectomy in the absence of folate supplementation is consistent with a potentially carcinogenic field's causing the appearance of the polyp.

Low colonocyte folate is associated with uracil misincorporation and global DNA hypomethylation in human colorectum.

Low folate status is a risk factor for colon carcinogenesis; mechanisms proposed to account for this relationship include uracil misincorporation into DNA and global DNA hypomethylation. We investigated whether such biomarkers are related to folate status in isolated colonocytes from colonoscopy patients. In cases with adenomatous polyps (n = 40) or hyperplastic polyps (n = 16), colonocytes were isolated from biopsies from the polyp, from a site adjacent to the polyp, and from normal mucosa 10-15 cm distal to the polyp. In polyp-free controls (n = 53), biopsies were taken from ascending, transverse, and descending areas of colon. Within adenoma cases, there was a trend (P-trend < 0.001) of decreasing colonocyte folate (pg/105 cells, mean ± CI) from the site distal to the polyp (16.9 ± 2.4), to the site adjacent to the polyp (14.7 ± 2.3), to the polyp (12.8 ± 2.0). Correspondingly, there were increases in uracil misincorporation (P-trend < 0.001) and global DNA hypomethylation (P-trend = 0.012) across the 3 sites. Colonocyte folate concentrations were significantly correlated with RBC folate concentrations, but only in individuals with generally lower (≤484 µg/L) RBC folate status (r = 0.54; P = 0.006; n = 24), and were also significantly lower in normal mucosa of cases with adenomatous polyps than in controls matched for colonic segment. In conclusion, localized folate deficiency in specific areas of colon might create carcinogenic fields and affect the development of colorectal polyps through uracil misincorporation and DNA hypomethylation; alternatively, the polyp itself might deplete folate in the surrounding tissue. Folate supplementation trials aimed at colon cancer prevention should target individuals with suboptimal folate status.

Impaired functioning of thermolabile methylenetetrahydrofolate reductase is dependent on riboflavin status: implications for riboflavin requirements.

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR; EC 1.7.99.5) supplies the folate needed for the metabolism of homocysteine. A reduction in MTHFR activity, as occurs in the homozygous state for the 677C-->T (so-called thermolabile) enzyme variant (TT genotype), is associated with an increase in plasma total homocysteine (tHcy). OBJECTIVE: In vitro studies suggest that the reduced activity of thermolabile MTHFR is due to the inappropriate loss of its riboflavin cofactor. We investigated the hypothesis that MTHFR activity in the TT genotype group is particularly sensitive to riboflavin status. DESIGN: We studied tHcy and relevant B-vitamin status by MTHFR genotype in a cross-sectional study of 286 healthy subjects aged 19-63 y (median: 27 y). The effect of riboflavin status was examined by dividing the sample into tertiles of erythrocyte glutathionine reductase activation coefficient, a functional index of riboflavin status. RESULTS: Lower red blood cell folate (P = 0.0001) and higher tHcy (P = 0.0082) concentrations were found in the TT group than in the heterozygous (CT) or wild-type (CC) groups. However, these expected relations in the total sample were driven by the TT group with the lowest riboflavin status, whose mean tHcy concentration (18.09 micromol/L) was almost twice that of the CC or CT group. By contrast, adequate riboflavin status rendered the TT group neutral with respect to tHcy metabolism. CONCLUSIONS: The high tHcy concentration typically associated with homozygosity for the 677C-->T variant of MTHFR occurs only with poor riboflavin status. This may have important implications for governments considering new fortification policies aimed at the prevention of diseases for which this genotype is associated with increased risk.

The yield of colonoscopy in average-risk patients with non-specific colonic symptoms.

OBJECTIVES: The need for full colonoscopies in average-risk patients with non-specific colonic symptoms is controversial. We aimed to evaluate: (1) the yield of full colonoscopy; (2) the prevalence of proximal neoplasia in these patients; (3) the yield if any of doing full colonoscopies to diagnose proximal lesions in patients in whom the distal colon was clear; (4) the significance of this yield with respect to age. DESIGN: This is a retrospective analysis to assess the value of open access colonoscopy. PATIENTS AND METHODS: All patients who underwent a colonoscopy in our Endoscopy Unit during January 1996 to December 1999 were assessed (n = 3357). RESULTS: We analysed 945 patients with average risk and non-specific colonic symptoms (significant risk factors excluded). The overall yield of adenomas was 5.8%. The yield of distal adenomas in patients > or= 50 years of age was 8.2% (37 out of 450) versus 0.2% in the 50 years group (one out of 495; = 0.0001). The proximal adenoma yield in > or= 50 year olds was 3.8% (17 out of 495) versus 0.2% in < 50 year olds (one out of 495) (P = 0.0001). CONCLUSIONS: In a cohort of average-risk patients with non-specific colonic symptoms attending an "open access" colonoscopy clinic, the yield for proximal adenomas is small in the < 50 years group. In patients aged < 50 years, distal colonic examination is all that is required, whereas a full colonoscopy may be justified in patients > or = 50 years old.

Postprandial serum folic acid response to multiple doses of folic acid in fortified bread.

The benefit of the introduction of mandatory folic acid fortification of all flour products in the USA in 1998 has been amply demonstrated in a reduction of neural tube defect births. Doubt has been cast on the actual level of fortification and recent calculations have shown that the level of folic acid fortification is likely to have been over twice the amount mandated. The implication of this is that a greater proportion of the population are likely to have consumed folic acid at >1 mg/d, the Food and Drug Administration safe upper level of intake. Using the criteria of appearance of synthetic folic acid in serum, the objective of this pilot study was to investigate the consequences of consumption of baked bread preparations containing 1 mg folic acid. Four healthy adult volunteers undertook each dosing schedule 2 weeks apart. This consisted of a single dose of 1000 microg, two doses of 500 microg, three doses of 333 microg, five doses of 200 microg and, finally, ten doses of 100 microg. Serum was collected pre- and postprandially and analysed for synthetic folic acid by a combined HPLC-microbiological assay for folic acid. Folic acid appeared in all subjects at all test doses, with the effect more pronounced as the standard dose was administered in smaller amounts over the test period. Approaches to optimise folic acid intake in target populations as part of a universal fortification strategy should take into consideration the potential hazard of over-exposure in groups consuming high amounts of flour-based products.

Comparison of transesophageal endoscopic plication (TEP) with laparoscopic Nissen fundoplication (LNF) in the treatment of uncomplicated reflux disease.

BACKGROUND: Transesophageal endoscopic plication (TEP) is a novel endotherapeutic approach in the management of gastroesophageal reflux disease (GERD). This non-randomized prospective study compares TEP with laparoscopic Nissen fundoplication (LNF). METHODS: Twenty-four consecutive patients treated with LNF, and 27 managed by TEP were studied. Symptom severity scores, endoscopy, 24 h esophageal pH and esophageal manometry and quality-of-life assessments were obtained pre- and posttreatment. RESULTS: In the LNF group the mean age was 36 yr (17-68) compared with 39 yr (22-62) in the TEP group. Symptom scoring, acid regurgitation score, reduction in the requirements of proton pump inhibitors (PPIs), and quality of life remained significantly improved in both groups at a median of 1 yr [10-18 months] follow-up post procedure. However, the improvement was significantly better in symptom score (p= 0.0383) and the control of acid reflux in the LNF group (p= 0.0007). Post-procedure dysphagia was more common in the LNF group. CONCLUSION: Both techniques improved symptom score, acid regurgitation, quality of life, and reduced the requirements for PPIs. The control of heartburn and acid reflux was better for LNF. TEP, like LNF, is a safe and effective method of management of symptomatic GERD but further developments are necessary to ensure control of esophageal acid reflux.

Evidence of unmetabolised folic acid in cord blood of newborn and serum of 4-day-old infants.

Oral folic acid above certain threshold doses results in unmetabolised folic acid in serum. This raises a number of public health safety issues, principally the potential to mask pernicious anaemia; more recently the theoretical potential for high-dose folic acid to promote cancer has been highlighted. In this paper we set out to examine the appearance of unmetabolised folic acid both in cord blood from newborn full-term and premature infants and serum from 4-d-old infants post-formula feeding. Blood was collected from the umbilical cord of eleven infants in the delivery room immediately after birth. A follow-up serum sample (n 9) was collected 4 d later from infants post-formula feeding. We detected unmetabolised folic acid in cord blood from all infants at birth. In addition, unmetabolised folic acid was present in serum of seven infants post-formula feeding, six of which had increased from birth. Our results imply that infants in Ireland, which does not yet have mandatory fortification, could potentially have circulatory unmetabolised folic acid at the time of birth. We do not know if the presence of folic acid in cord blood will have any adverse consequences. However, if theoretical safety concerns are borne out by future research, the likelihood is that the longer the exposure the more likely the potential for harm. This would also be the case in infants exposed to unmetabolised folic acid as a result of formula feeding.

Low pH and Helicobacter pylori increase nuclear factor kappa B binding in gastric epithelial cells: a common pathway for epithelial cell injury?

Helicobacter pylori infection results in peptic ulceration and chronic gastritis through mechanisms which are not fully elucidated. Live H. pylori activate the pro-inflammatory transcription factor NF-kappaB in gastric epithelial cells. Patients may have peptic ulcer disease in the absence of H. pylori infection; therefore other factors contribute to the inflammatory process. Maximal acid output in patients with H. pylori infection and duodenal ulceration is significantly increased indicating a role for acid in the pathogenesis of mucosal ulceration. The effect of low pH on NF-kappaB activation in gastric epithelial cells has not been studied. Human gastric epithelial cells (AGS) were exposed to a range of pH changes in the presence or absence of H. pylori. NF-kappaB DNA-binding and cytosolic IkappaB-alpha were measured using electrophoretic mobility shift assay and Western blotting. NF-kappaB DNA-binding in gastric epithelial cells dramatically increased when the pH of the culture medium decreased. Increases in NF-kappaB nuclear binding were paralleled by decreasing amounts of cytosolic IkappaB-alpha. These findings were similar but less potent than those observed when cells were exposed to H. pylori. Low pH resulted in enhancement of H. pylori-induced NF-kappaB nuclear binding. DNA binding of NF-kappaB activation secondary to low pH was attenuated by PD98059 but not by SB203580. Similar to H. pylori, low pH potently and independently augments NF-kappaB nuclear binding in AGS cells and such activation appears to be mediated through MEK1-dependant signaling pathways.

Innovations in gastro-intestinal endoscopy: endoscopic antireflux therapies for gastro-oesophageal reflux disease.

BACKGROUND: Gastro-oesophageal reflux disease (GORD) is a common disorder which significantly impairs the quality of life. Recently a number of endoscopic antireflux procedures have been described, with a view to the management of GORD, thus obviating the need for long-term proton pump inhibitors and the cost and potential risk of laparoscopic Nissen fundoplication. AIM: To evaluate the status of new techniques using gastro-intestinal endoscopy for the management of GORD. METHODS: Review of the literature (publications and abstracts) regarding safety, efficacy, and durability of these new antireflux procedures. RESULTS: These antireflux techniques have produced significant improvement in GORD symptomatology and quality of life and have reduced the use of antireflux medication, without causing serious morbidity or mortality. However, the majority of these techniques have failed to adequately control oesophageal acid reflux. CONCLUSIONS: Endoscopic antireflux therapies have the potential to treat patients with GORD. However, further studies are necessary to determine what modifications to these techniques are required in order to produce the maximum clinical efficacy and durability.

Inflammatory bowel disease: the role of inflammatory cytokine gene polymorphisms.

The mechanisms responsible for development of inflammatory bowel disease (IBD) have not been fully elucidated, although the main cause of disease pathology is attributed to up-regulated inflammatory processes. The aim of this study was to investigate frequencies of polymorphisms in genes encoding pro-inflammatory and anti-inflammatory markers in IBD patients and controls. We determined genotypes of patients with IBD (n= 172) and healthy controls (n= 389) for polymorphisms in genes encoding various cytokines (interleukin (IL)-1beta, IL-6, tumour necrosis factor (TNF), IL-10, IL-1 receptor antagonist). Association of these genotypes to disease incidence and pathophysiology was investigated. No strong association was found with occurrence of IBD. Variation was observed between the ulcerative colitis study group and the control population for the TNF-alpha-308 polymorphism (p= 0.0135). There was also variation in the frequency of IL-6-174 and TNF-alpha-308 genotypes in the ulcerative colitis group compared with the Crohn's disease group (p= 0.01). We concluded that polymorphisms in inflammatory genes are associated with variations in IBD phenotype and disease susceptibility. Whether the polymorphisms are directly involved in regulating cytokine production, and consequently pathophysiology of IBD, or serve merely as markers in linkage disequilibrium with susceptibility genes remains unclear.