Probiotic factors partially prevent changes to caspases 3 and 7 activation and transepithelial electrical resistance in a model of 5-fluorouracil-induced epithelial cell damage.

The potential efficacy of a probiotic-based preventative strategy against intestinal mucositis has yet to be investigated in detail. We evaluated supernatants (SN) from Escherichia coli Nissle 1917 (EcN) and Lactobacillus rhamnosus GG (LGG) for their capacity to prevent 5-fluorouracil (5-FU)-induced damage to intestinal epithelial cells. A 5-day study was performed. IEC-6 cells were treated daily from days 0 to 3, with 1 mL of PBS (untreated control), de Man Rogosa Sharpe (MRS) broth, tryptone soy roth (TSB), LGG SN, or EcN SN. With the exception of the untreated control cells, all groups were treated with 5-FU (5 µM) for 24 h at day 3. Transepithelial electrical resistance (TEER) was determined on days 3, 4, and 5, while activation of caspases 3 and 7 was determined on days 4 and 5 to assess apoptosis. Pretreatment with LGG SN increased TEER (p < 0.05) compared to controls at day 3. 5-FU administration reduced TEER compared to untreated cells on days 4 and 5. Pretreatment with MRS, LGG SN, TSB, and EcN SN partially prevented the decrease in TEER induced by 5-FU on day 4, while EcN SN also improved TEER compared to its TSB vehicle control. These differences were also observed at day 5, along with significant improvements in TEER in cells treated with LGG and EcN SN compared to healthy controls. 5-FU increased caspase activity on days 4 and 5 compared to controls. At day 4, cells pretreated with MRS, TSB, LGG SN, or EcN SN all displayed reduced caspase activity compared to 5-FU controls, while both SN groups had significantly lower caspase activity than their respective vehicle controls. Caspase activity in cells pretreated with MRS, LGG SN, and EcN SN was also reduced at day 5, compared to 5-FU controls. We conclude that pretreatment with selected probiotic SN could prevent or inhibit enterocyte apoptosis and loss of intestinal barrier function induced by 5-FU, potentially forming the basis of a preventative treatment modality for mucositis.

Effects of a Lactobacillus reuteri BR11 mutant deficient in the cystine-transport system in a rat model of inflammatory bowel disease.

BACKGROUND: Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract associated with altered composition of the gut microbiota. Lactobacillus reuteri BR11 (BR11) has recently been reported to reduce the severity of experimental IBD because of its probiotic properties possibly attributed to a mechanism of thiol production via its unique cysteine/cystine-transport system. AIM: We compared BR11 and a BR11 mutant deficient in the cystine-uptake system (PNG201), for their capacity to reduce the severity of experimental colitis. METHODS: Male Sprague-Dawley rats (n = 8 per group) were gavaged (1 ml/day) with skim milk, BR11 or PNG201 (1 × 10(9) CFU/ml) for 12 days. Rats consumed either water or 2% dextran sulfate sodium in drinking water from days 6 to 12 to induce colitis. Metabolism data, disease activity index, intestinal mucin profile, and histological analyses were assessed and compared by ANOVA. RESULTS: Assessed histologically, DSS administration resulted in significant colonic deterioration, including loss of crypt area and increased damage severity. BR11 administration only partially alleviated the DSS effects, with a minor improvement in crypt area (P < 0.05). Administration of the PNG201 mutant strain to colitic animals failed to achieve significance (P > 0.05) against the DSS control for any of the end-points. However, the mutant strain induced significantly greater (P < 0.05) histological severity compared with BR11-treated colitic animals, indicative of possible exacerbation of colitis. CONCLUSIONS: The cystine-uptake system only minimally affects the biological effects of BR11, as evidenced by histological and macroscopic colitic changes.

Evidence supporting the use of probiotics for the prevention and treatment of chemotherapy-induced intestinal mucositis.

Although chemotherapy remains the current best practice for the treatment of neoplasia, the severity of its associated side-effects continues to impact detrimentally on the quality of life. Mucositis can affect both the oral cavity and intestine, and represents one of the most common side-effects of chemotherapy. It is characterized by ulceration, inflammation, diarrhoea, and intense abdominal pain. Despite extensive research there remains no definitive therapy for mucositis. This may be due to the multiple factors which contribute to its pathogenesis, including up-regulation of pro-inflammatory cytokines, increased apoptosis of epithelial cells, alteration of the gastrointestinal microbiota, and damage to the epithelium. Although employed increasingly in other gastrointestinal disorders, probiotics are yet to be comprehensively investigated in the treatment or prevention of chemotherapy-induced mucositis. Probiotic-based therapies have been shown to exert beneficial effects, including modulation of the microbiota and inhibition of pro-inflammatory cytokines. This review outlines the current evidence supporting the use of probiotics in intestinal mucositis, and suggests further research directions for the future.

Fatty acids as potential adjunctive colorectal chemotherapeutic agents.

Fatty acids (FA) are bioactive molecules which have potential as adjunctive chemotherapeutic agents. FA are classified as short-, medium; or long-chain on the basis of the number of carbon atoms in the aliphatic chain and have been reported to induce apoptosis in vitro in a range of cancer cell types, including breast, tongue, cervix and colorectal. However, to date the chain length exerting optimal anti-neoplastic properties remains undefined. Short chain fatty acids, such as butyrate (C4:0), have induced high rates of in vitro apoptosis, presumably related to epigenetic modification, cell cycle arrest and activation of pro-apoptotic genes. Medium chain fatty acids have demonstrated in vivo and in vitro cytotoxic and anti-microbial properties; however, scant evidence currently exists on their anti-neoplastic potential. Longer unsaturated fatty acids (C16-24: ω3-9), including conjugated linoleic acid and eicosapentaenoic acid, also exhibit in vitro anti-proliferative actions, including induction of oxidative stress and modification of intracellular signalling pathways. Although incorporation of FA into CRC chemotherapy regimens is in its infancy, evidence is accumulating to allow identification of the FA chain length capable of exerting the most effective anti-neoplastic activity.

Probiotic factors partially improve parameters of 5-fluorouracil-induced intestinal mucositis in rats.

Certain live bacteria have demonstrated preliminary indications of efficacy for the treatment of chemotherapy-induced intestinal mucositis. However, probiotic derived supernatants (SN) have yet to be investigated in the mucositis setting. We evaluated SN from Escherichia coli Nissle 1917 (EcN) and Lactobacillus fermentum BR11 (BR11) for their capacity to decrease 5-Fluorouracil (5-FU)-induced damage in vivo. Female Dark Agouti rats were gavaged with 1 mL of either SN or vehicle daily (days 0-8) and intraperitoneally injected with 5-FU (150 mg/kg) on day 5 to induce mucositis. On day 9, animals were culled and intestinal tissues collected. Significantly lower histological damage scores were apparent in the jejunum of 5-FU treated rats receiving SN compared to 5-FU controls. Myeloperoxidase levels in the jejunum of 5-FU treated rats were increased in vehicle and BR11 SN treatments compared to untreated controls, whereas no significant increase was observed after EcN SN treatment. 5-FU treatment significantly reduced villus height and crypt depth in the jejunum compared to normal controls; however no significant reduction in these parameters was observed in 5-FU treated rats receiving either SN. We conclude that bacterial SN, especially EcN, partially protect the intestine from 5-FU mucositis. Further studies are required to define specific mechanisms by which SN exert their beneficial effects.

Effects of Streptococcus thermophilus TH-4 on intestinal mucositis induced by the chemotherapeutic agent, 5-Fluorouracil (5-FU).

Beneficial bacteria (probiotics) and probiotic-derived factors have the potential to ameliorate disorders of the intestine. The aim of this study was to compare live Streptococcus thermophilus TH-4 (TH-4), dead TH-4 and TH-4 supernatant in rats treated with 5-Fluorouracil. Rats were randomly allocated to five treatment groups (n=8-10): Saline+Water; 5-FU+Skim Milk; 5-FU+Live TH-4; 5-FU+Supernatant TH-4; and 5-FU+Dead TH-4. 5-FU (150mg.kg(-1)) was administered by a single intraperitoneal injection on day 0; animals were killed on day 4. Treatments were administered daily from days -2 to 3 via oro-gastric gavage. Metabolic parameters were measured daily. Blood was obtained by cardiac puncture, and intestinal tissues removed for quantitative and qualitative histological assessment, including: villous height and area; crypt depth and area, mitotic count and crypt fission; biochemical determination of sucrase and myeloperoxidase (MPO) activity; and disease severity scoring. One-way ANOVA statistical analyses were conducted for the majority of outcome measures. Live TH-4 significantly reduced disease severity score by 13% (p< 0.05), and partially normalised mitotic counts compared with 5-FU+Skim milk controls. Live and supernatant TH-4 reduced crypt fission by 69% and 48% (p< 0.05), respectively, compared to 5-FU+Skim Milk controls. No significant differences (p> 0.05) in the occurrence of bacteraemia were evident across all groups. Live TH-4 partially normalised mitotic count and histological severity score in 5-FU treated rats. The inhibitory effect of live TH-4 and TH-4 supernatant on crypt fission suggests therapeutic utility in the prevention of disorders characterised by increased crypt fission, such as colorectal carcinoma.

Effects of Streptococcus thermophilus TH-4 on intestinal mucositis induced by the chemotherapeutic agent 5-Fluorouracil (5-FU).

Beneficial bacteria (probiotics) and probiotic-derived factors have the potential to ameliorate disorders of the intestine. The aim of this study was to compare live Streptococcus thermophilus TH-4 (TH-4), dead TH-4 and TH-4 supernatant in rats treated with 5-Fluorouracil. Rats were randomly allocated to five treatment groups (n = 8­10): Saline + Water; 5-FU + Skim Milk; 5-FU+ Live TH-4; 5-FU + Supernatant TH-4; and 5-FU + Dead TH-4.5-FU (150 mg.kg-1) was administered by a single intraperitoneal injection on day zero; animals were killed on day four. Treatments were administered daily from days -2 to +3 via oro-gastric gavage. Metabolic parameters were measured daily. Blood was obtained by cardiac puncture, and intestinal tissues removed for quantitative and qualitative histological assessment, including: villus height and area; crypt depth and area, mitotic count and crypt fission;biochemical determination of sucrase and myeloperoxidase (MPO)activity; and disease severity scoring. One-way ANOVA statistical analyses were conducted for the majority of outcome measures. Live TH-4 significantly reduced disease severity score by 13% (p< 0.05), and partially normalized mitotic counts compared with 5-FU + Skim Milk controls. Live and Supernatant TH-4 reduced crypt fission by 69% and 48% (p < 0.05), respectively, compared to 5-FU + Skim Milk controls. No significant differences (p > 0.05) in the occurrence of bacteraemia were evident across all groups. Live TH-4 partially normalized mitotic count and histological severity score in 5-FU treated rats. The inhibitory effect of live TH-4 and TH-4 Supernatant on crypt fission suggests therapeutic utility in the prevention of disorders characterized by increased crypt fission,such as colorectal carcinoma.