Peter W. Emery

Folate status, genomic DNA hypomethylation, and risk of colorectal adenoma and cancer: a case control study.

BACKGROUND & AIMS Low folate intake may increase risk for colorectal cancer by inducing DNA hypomethylation. This study reports the influence of folate status, DNA methylation, and polymorphisms of methylenetetrahydrofolate reductase (MTHFR 677C-->T and 1298A-->C), methionine synthase (MS 2756A-->G), and cystathionine-beta-synthase (CBS 844ins68) on risk for developing colorectal neoplasia. METHODS Thirty-five patients with adenoma, 28 patients with cancer, and 76 controls were recruited for a case control study. Recruitment consent rate was 98%. Blood samples were obtained for determination of blood folates, vitamin B(12), homocysteine, DNA methylation, and genotypes. Tissue biopsy samples were obtained at colonoscopy for determination of DNA methylation in colonic mucosa. Folate status was assessed by constructing a score from estimates of dietary intake and serum and erythrocyte folate. RESULTS Cancer patients had 26% lower folate status (95% confidence interval [CI]: 6% to 44%, P = 0.01) and 21% lower serum vitamin B(12) concentration (95% CI: -38% to 1%, P = 0.06) compared with controls. [(3)H] methyl incorporation into colonic DNA was 26% higher in patients with adenoma (95% CI: 8% to 56%, P = 0.009) and 30% higher in patients with cancer (95% CI: -3% to 48%, P = 0.08) compared with controls. High folate status was associated with decreased risk for cancer (P = 0.01 for trend). Colonic and leukocyte DNA hypomethylation were associated with increased risk for adenoma (P = 0.02 and P = 0.01 for trend, respectively) and a nonsignificantly increased risk for cancer (P = 0.09 and P = 0.08 for trend, respectively). CONCLUSIONS Low folate status and DNA hypomethylation are associated with colorectal neoplasia.

Effect of folic acid supplementation on genomic DNA methylation in patients with colorectal adenoma

Background and aims: A low dietary folate intake can cause genomic DNA hypomethylation and may increase the risk of colorectal neoplasia. The hypothesis that folic acid supplementation increases DNA methylation in leucocytes and colorectal mucosa was tested in 31 patients with histologically confirmed colorectal adenoma using a randomised, double blind, placebo controlled, parallel design. Methods: Subjects were randomised to receive either 400 μg/day folic acid supplement (n = 15) or placebo (n = 16) for 10 weeks. Genomic DNA methylation, serum and erythrocyte folate, and plasma homocysteine concentrations were measured at baseline and post intervention. Results: Folic acid supplementation increased serum and erythrocyte folate concentrations by 81% (95% confidence interval (CI) 57–104%; p<0.001 v placebo) and 57% (95% CI 40–74%; p<0.001 v placebo), respectively, and decreased plasma homocysteine concentration by 12% (95% CI 4–20%; p = 0.01 v placebo). Folic acid supplementation resulted in increases in DNA methylation of 31% (95% CI 16–47%; p = 0.05 v placebo) in leucocytes and 25% (95% CI 11–39%; p = 0.09 v placebo) in colonic mucosa. Conclusions: These results suggest that DNA hypomethylation can be reversed by physiological intakes of folic acid.

Substrate-dependent regulation of intracellular amino acid concentrations in cultured bovine aortic endothelial cells

Amino acid deprivation induces adaptive changes in amino acid transport and the intracellular amino acid pool in cultured cells. In this study intracellular amino acid levels were determined in cultured bovine aortic endothelial cells (EC) deprived of L-arginine or total amino acids for 1, 3, 6 and 24 h. Amino acid concentrations were analyzed by reverse phase HPLC after precolumn derivatisation. Under normal culture conditions levels of L-arginine L-citrulline, total essential and non-essential amino acids were 840 +/- 90 microM, 150 +/- 40 microM, 11.4 +/- 0.9 mM and 53.3 +/- 3.4 mM (n = 9), respectively. In EC deprived of L-arginine or all amino acids for 24 h L-arginine and L-citrulline levels were 200 microM and 50 microM, and 670 microM and 100 microM Deprivation of L-arginine or total amino acids induced rapid (1 h) decreases (30 - 50%) in the levels of other cationic (lysine, ornithine) and essential branched-chain (valine, isoleucine, leucine) and aromatic (phenylalanine, tryptophan) amino acids. L-glutamine was reduced markedly in EC deprived of total amino acids for 1 h - 6 h but actually increased 3-fold in EC deprived of L-arginine for 6 h or 24 h. Arginine deprivation resulted in a rapid decrease in the total intracellular amino acid pool, however concentrations were restored after 24 h. Increased amino acid transport and/or reduced protein synthesis may account for the restoration of amino acid levels in EC deprived of L-arginine. The sustained reduction in the free amino acid pool of EC deprived of all amino acids may reflect utilization of intracellular amino acids for protein synthesis.

Oral Nutritional Interventions in Malnourished Patients With Cancer: A Systematic Review and Meta-Analysis

BACKGROUND International guidelines on the nutritional management of patients with cancer recommend intervention with dietary advice and/or oral nutritional supplements in patients who are malnourished or those judged to be at nutritional risk, but the evidence base for these recommendations is lacking. We examined the effect of oral nutritional interventions in this population on nutritional and clinical outcomes and quality of life (QOL). METHODS Electronic searches of several databases including MEDLINE, EMBASE, and CINAHL (from the first record to February 2010) were searched to identify randomized controlled trials of patients with cancer who were malnourished or considered to be at risk of malnutrition and receiving oral nutritional support compared with routine care. We performed a meta-analysis using a fixed effect model, or random effects models when statistically significant heterogeneity was present, to calculate relative risk (mortality) or mean difference (weight, energy intake, and QOL) with 95% confidence intervals (CIs). Heterogeneity was determined by using the χ(2) test and the I(2) statistic. All statistical tests were two-sided. RESULTS Thirteen studies were identified and included 1414 participants. The quality of the studies varied, and there was considerable clinical and statistical heterogeneity. Nutritional intervention was associated with statistically significant improvements in weight and energy intake compared with routine care (mean difference in weight = 1.86 kg, 95% CI = 0.25 to 3.47, P = .02; and mean difference in energy intake = 432 kcal/d, 95% CI = 172 to 693, P = .001). However, after removing the main sources of heterogeneity, there was no statistically significant difference in weight gain or energy intake. Nutritional intervention had a beneficial effect on some aspects of QOL (emotional functioning, dyspnea, loss of appetite, and global QOL) but had no effect on mortality (relative risk = 1.06, 95% CI = 0.92 to 1.22, P = .43; I(2) = 0%; P(heterogeneity) = .56). CONCLUSION Oral nutritional interventions are effective at increasing nutritional intake and improving some aspects of QOL in patients with cancer who are malnourished or are at nutritional risk but do not appear to improve mortality.

Influence of folate status on genomic DNA methylation in colonic mucosa of subjects without colorectal adenoma or cancer

DNA hypomethylation may increase the risk of colorectal cancer. The main aim of this study was to assess the influence of folate status (serum and erythrocyte folate and plasma homocysteine concentrations) on DNA methylation. Methylenetetrahydrofolate reductase (MTHFR 677C → T and 1298A → C), methionine synthase (MS 2756A → G) and cystathionine synthase (CBS 844ins68) polymorphisms were measured to account for potential confounding effects on folate status and DNA methylation. A total of 68 subjects (33 men and 35 women, 36–78 years) free from colorectal polyps or cancer were recruited in a cross-sectional study. Tissue biopsies were obtained at colonoscopy for the determination of DNA methylation in colonic mucosa using an in vitro radiolabelled methyl acceptance assay. Serum and erythrocyte folate were inversely correlated with plasma homocysteine (r=−0.573, P<0.001 and r=−0.307, P=0.01 respectively) and DNA hypomethylation in colonic mucosa (r=−0.311, P=0.01 and r=−0.356, P=0.03). After adjusting for gender, age, body mass index, smoking and genotype, there were weak negative associations between serum and erythrocyte folate and colonic DNA hypomethylation (P=0.07 and P=0.08, respectively).

Dietary counselling and food fortification in stable COPD: a randomised trial

Background: Malnutrition in chronic obstructive pulmonary disease (COPD) is associated with a poor prognosis, yet evidence to support the role of dietary counselling and food fortification is lacking. A study was undertaken to assess the impact of dietary counselling and food fortification on outcome in outpatients with COPD who are at risk of malnutrition. Methods: A randomised controlled unblinded trial was performed in 59 outpatients with COPD (6 months intervention and 6 months follow-up). The intervention group received dietary counselling and advice on food fortification and the controls received a dietary advice leaflet. Outcome measures were nutritional status, respiratory and skeletal muscle strength, respiratory function, perceived dyspnoea, activities of daily living (ADL) and quality of life. Results: The intervention group consumed more energy (difference 194 kcal/day; p = 0.02) and protein (difference 11.8 g/day; p<0.001) than controls. The intervention group gained weight during the intervention period and maintained weight during follow-up; the controls lost weight throughout the study. Significant differences were observed between the groups in St George’s Respiratory Questionnaire total score (difference 10.1; p = 0.02), Short Form-36 health change score (difference 19.2; p = 0.029) and Medical Research Council dyspnoea score (difference 1.0; p = 0.03); the difference in ADL score approached statistical significance (difference 1.5; p = 0.06). No differences were observed between groups in respiratory function or skeletal and respiratory muscle strength. Improvements in some variables persisted for 6 months beyond the intervention period. Conclusion: Dietary counselling and food fortification resulted in weight gain and improvements in outcome in nutritionally at-risk outpatients with COPD, both during and beyond the intervention period.

Separation and identification of rat skeletal muscle proteins using two-dimensional gel electrophoresis and mass spectrometry.

Skeletal muscle plays a major role in whole body protein metabolism, and changes in the rates of synthesis and degradation of proteins are likely to lead to characteristic changes in the amounts of different proteins in muscle under various physiological and pathological conditions. This paper demonstrates the feasibility of a proteomic approach to analyzing the protein composition of skeletal muscle. We report here the initial establishment of two‐dimensional gel electrophoresis (2‐D PAGE) reference maps for mixed skeletal muscle taken from the abdominal wall of a normal adult rat. We used immobilized pH gradients of 3–10 (non‐linear) and 4–7 (linear), and matrix assisted laser desorption/ionization – time of flight mass spectrometry for protein identification by peptide mass fingerprinting. More than 600 protein spots were detected on each gel, of which 100 were excised and characterized. In‐gel digestion followed by peptide mass fingerprinting enabled tentative identification of 74 of these, which included a wide range of myofibrillary and sarcoplasmic proteins. This database should provide the nucleus of a valuable resource for investigation of the biochemical basis of skeletal muscle pathologies in general and such specific disorders as alcoholic myopathy and injury.

A review of the evidence for the impact of improving nutritional care on nutritional and clinical outcomes and cost.

BACKGROUND The association between malnutrition and poor clinical outcome is well-established, yet most research has focussed on the role of artificial nutritional support in its management. More recently, emphasis has been placed on the provision of adequate nutritional care, including nutritional screening and the routine provision of food and drink. The aim of this literature review is to establish the evidence for the efficacy of interventions that might result in improvements in nutritional and clinical outcomes and costs. METHODS A structured literature review was conducted investigating the role of nutritional care interventions in adults, and their effects on nutritional and clinical outcomes and costs, in all healthcare settings. Ten databases were searched electronically using keywords relating to nutritional care, patient outcomes and healthcare costs. High quality trials were included where available. RESULTS Two hundred and ninety-seven papers were identified and reviewed. Of these, only two randomised, controlled trials and six other trials were identified that addressed the major issues. A further 99 addressed some aspects of the provision of nutritional care, although very few formally evaluated nutritional or clinical outcomes and costs. CONCLUSIONS This review reveals a serious lack of evidence to support interventions designed to improve nutritional care, in particular with reference to their effects on nutritional and clinical outcomes and costs. The review suggests that screening alone may be insufficient to achieve beneficial effects and thus more research is required to determine the most cost-effective interventions in each part of the nutritional care pathway, in a variety of healthcare settings and across all age ranges, to impact upon nutritional and clinical outcomes.

Metabolic changes in malnutrition

This paper is concerned with malnutrition caused by inadequate intake of all the major nutrients rather than deficiency diseases relating to a single micronutrient. Three common situations are recognised: young children in third world countries with protein-energy malnutrition; adults in the same countries who are chronically adapted to subsisting on marginally inadequate diets; and patients who become malnourished as a result of chronic diseases. In all these situations infectious diseases are often also present, and this complicates the interpretation of biochemical and physiological observations. The metabolic response to starvation is primarily concerned with maintaining a supply of water-soluble substrates to supply energy to the brain. Thus there is an initial rise in metabolic rate, reflecting gluconeogenic activity. As fasting progresses, gluconeogenesis is suppressed to minimise muscle protein breakdown and ketones become the main fuel for the brain. With chronic underfeeding the basal metabolic rate per cell appears to fall, but the mechanistic basis for this is not clear. The main adaptation to chronic energy deficiency is slow growth and low adult body size, although the reduction in energy requirement achieved by this is partially offset by the preservation of the more metabolically active organs at the expense of muscle, which has a lower metabolic rate. The interaction between malnutrition and the metabolic response to trauma has been studied using an animal model. The rise in energy expenditure and urinary nitrogen excretion following surgery were significantly attenuated in malnourished rats, suggesting that malnutrition impairs the ability of the body to mobilise substrates to support inflammatory and reparative processes. However, the healing process in wounded muscle remained unimpaired in malnutrition, suggesting that this process has a high biological priority.

Recent Advances in Alcohol-Induced Adduct Formation

This article presents the proceedings of a symposium presented at the ISBRA 12th World Congress on Biomedical Alcohol Research, held in Heidelberg/Mannheim, Germany, September 29 through October 2, 2004. The organizers of the symposium were Simon Worrall and Victor Preedy, and the symposium was chaired by Onni Niemela and Geoffrey Thiele. The presentations scheduled for this symposium were (1) Adduct chemistry and mechanisms of adduct formation, by Thomas L. Freeman; (2) Malondialdehyde- acetaldehyde adducts: the 2004 update, by Geoffrey Thiele; (3) Adduct formation in the liver, by Simon Worrall; (4) Protein adducts in alcoholic cardiomyopathy, by Onni Niemela; and (5) Alcoholic skeletal muscle myopathy: a role for protein adducts, by Victor R. Preedy.