Dietary fibre on cell proliferation in large bowel mucosal crypts near or away from lymphoid nodules and on mineral bioavailability

Comparative studies of the antiproliferative effects of ginseng polysaccharides on HT-29 human colon cancer cells

Ginseng polysaccharide has anticancer activity. However, the structure-activity relationship and the activity mechanism are still unclear. Therefore, it is necessary to study the anticancer activity of structurally different ginseng polysaccharide fractions and their potential mechanisms. Ginseng polysaccharide fractions and their temperature-modified products were assayed for their effects on HT-29 cell proliferation by MTT assay, on cell cycle progression by flow cytometry, and on caspase-3 activation by western blot analysis. The HG-rich ginseng pectin inhibited cell proliferation and induced cell cycle arrest in the G2/M phase. The temperature-modified HG-rich pectin had dramatically increased antiproliferative effect and induced apoptosis accompanied by the activation of caspase-3. Starch-like glucan and arabinogalactan of ginseng exhibited no antiproliferative effects. Even after temperature modification, their inhibitory effects either remained unchanged or increased slightly. The HG-rich pectin exerts its antiproliferative effect via cell cycle arrest and the temperature modification markedly increased the antiproliferative effect.

Effects of fermentable carbohydrates and low dietary phosphorus supply on the chemical composition of faecal bacteria and microbial metabolites in the gastrointestinal tract of pigs

The objective was to determine the effects of fermentable carbohydrates on phosphorus (P) metabolism, the chemical composition of the faecal mixed bacterial mass (MBM) and the microbial activity in the large intestine (LI) of pigs. Eight barrows (mean BW 35.9 +/- 0.9 kg), fitted with simple T-cannulas at the terminal ileum, were either fed a low-P corn-soybean meal-based control diet or 75% of the control diet supplemented with 25% cellulose, starch or pectin according to a 4 x 3 Latin Square design. Both pectin and cellulose caused higher faecal than ileal P recoveries. Ileal volatile fatty acids (VFA) levels were more pronounced for the starch (p < 0.05) rather than the cellulose and pectin treatments, whereas pectin resulted in a higher faecal VFA concentration in comparison to starch and cellulose (p < 0.05). The differences in faecal VFA concentrations corresponded to the pH values obtained in faeces. The N content of MBM was higher (p < 0.05) when cellulose was supplemented. Pectin caused a decrease in the P content of the MBM compared to the control (p < 0.05). As a result, the N:P ratio was significantly higher for the pectin (N:P = 4.33) than for the control treatment (N:P = 2.63), while the Ca:P ratio remained constant for all treatments, suggesting changes in the accumulation of N, P and Ca in MBM, probably due to changes in the species composition and activity of the microflora.

TGF-alpha expression as a potential biomarker of risk within the normal-appearing colorectal mucosa of patients with and without incident sporadic adenoma

BACKGROUND

Transforming growth factor-alpha (TGF-alpha), a stimulatory growth factor and member of the epidermal growth factor family, is a mediator of oncogenesis and malignant progression in colorectal carcinogenesis. Limited evidence suggests its utility as a growth-related biomarker of risk for colorectal cancer.

METHODS

We measured expression of TGF-alpha in biopsies of normal-appearing colorectal mucosa using automated immunohistochemistry and quantitative image analysis in a subsample of 29 cases and 31 controls from a colonoscopy-based case-control study (n = 203) of biomarkers of risk for incident sporadic colorectal adenoma. Diet, lifestyle, and medical history were assessed with validated questionnaires.

RESULTS

TGF-alpha expression in the rectum was 51% higher in cases compared with controls (P = 0.05) and statistically significantly associated with accepted risk factors for colorectal neoplasms (36% lower among nonsteroidal anti-inflammatory drug users, 49% lower among women using hormone replacement therapy, 79% higher among persons with a family history of colorectal cancer).

CONCLUSIONS

TGF-alpha expression in the normal-appearing rectal mucosa shows promise as an early, potentially modifiable biomarker of risk for colorectal cancer.

Protective effect of comaruman, a pectin of cinquefoil Comarum palustre L., on acetic acid-induced colitis in mice

The efficacy of comaruman CP, a pectin of marsh cinquefoil Comarum palustre L., was investigated using a model of acetic acid-induced colitis in mice. Mice were administered comaruman CP orally 2 days prior to rectal injection of 5% acetic acid and examined for colonic damage 24 hr later. Colonic inflammation was characterized by macroscopical injury, higher levels of myeloperoxidase activity, enhanced vascular permeability, and diminution of colonic mucus. Oral administration of comaruman CP was found to prevent progression of colitis. Colonic macroscopic scores and the total square of damage were significantly reduced in mice treated with CP compared with the vehicle-treated colitis group. Peroral pretreatment of mice with comaruman CP was shown to decrease tissue myeloperoxidase activity in colons compared with the colitis group. Comaruman CP was found to stimulate production of mucus by colons of normal and colitis mice. Comaruman CP decreased the inflammatory status of normal mice as elicited by reduction of vascular permeability and adhesion of peritoneal neutrophils and macrophages. Thus, a preventive effect of comaruman on acetic acid-induced colitis in mice was detected. Reduction of neutrophil infiltration and enhancement of colon-bound mucus may be implicated in the protective effect of comaruman.