Effects of Supernatants from Escherichia coli Nissle 1917 and Faecalibacterium prausnitzii on Intestinal Epithelial Cells and a Rat Model of 5-Fluorouracil-Induced Mucositis.

Faecalibacterium prausnitzii (Fp) and Escherichia coli Nissle 1917 (EcN) are probiotics, which have been reported to ameliorate certain gastrointestinal disorders. We evaluated the effects of supernatants (SN) derived from Fp and EcN on 5-fluorouracil (5-FU)-treated intestinal cells and in a rat model of mucositis. In vitro: IEC-6, Caco-2, and T-84 cells were analyzed for viability and monolayer permeability. In vivo: Female dark agouti rats were gavaged with Fp or EcN SN and injected intraperitoneally with saline (control) or 5-FU to induce mucositis. Rats were euthanized and intestinal tissues collected for myeloperoxidase assay and histological analyses. In vitro: Caco-2 cell viability was further reduced when treated with Fp SN + 5-FU compared to 5-FU controls. In both Caco-2 and T-84 cells, Fp SN partially prevented the decrease in transepithelial electrical resistance (TER) caused by 5-FU administration. In vivo: 5-FU-injected rats administered Fp SN or EcN SN partly prevented body weight loss and normalized water intake compared to 5-FU controls. These results suggest a growth inhibitory mechanism of Fp SN action on transformed epithelial cells that could be mediated by effects on tight junctions. Factors derived from Fp SN and EcN SN could have a role in reducing the severity of intestinal mucositis.

Prebiotics: A Potential Treatment Strategy for the Chemotherapy-damaged Gut?

Mucositis, characterized by ulcerative lesions along the alimentary tract, is a common consequence of many chemotherapy regimens. Chemotherapy negatively disrupts the intestinal microbiota, resulting in increased numbers of potentially pathogenic bacteria, such as Clostridia and Enterobacteriaceae, and decreased numbers of "beneficial" bacteria, such as Lactobacilli and Bifidobacteria. Agents capable of restoring homeostasis in the bowel microbiota could, therefore, be applicable to mucositis. Prebiotics are indigestible compounds, commonly oligosaccharides, that seek to reverse chemotherapy-induced intestinal dysbiosis through selective colonization of the intestinal microbiota by probiotic bacteria. In addition, evidence is emerging that certain prebiotics contribute to nutrient digestibility and absorption, modulate intestinal barrier function through effects on mucin expression, and also modify mucosal immune responses, possibly via inflammasome-mediated processes. This review examines the known mechanisms of prebiotic action, and explores their potential for reducing the severity of chemotherapy-induced mucositis in the intestine.

Factors derived from Escherichia coli Nissle 1917, grown in different growth media, enhance cell death in a model of 5-fluorouracil-induced Caco-2 intestinal epithelial cell damage.

We evaluated supernatants (SNs) from Escherichia coli Nissle 1917 (EcN) grown in commonly used growth media for their capacity to affect the viability of Caco-2 colon cancer cells in the presence and absence of 5-Fluorouracil (5-FU) chemotherapy. EcN was grown in Luria-Bertani (LB), tryptone soya (TSB), Man Rogosa Sharpe (MRS), and M17 broth supplemented with 10% (v/v) lactose solution (M17). Human Caco-2 colon cancer cells were treated with DMEM (control), growth media alone (LB, TSB, MRS, and M17) or EcN SNs derived from these 4 media, in the presence and absence of 5-FU. Cell viability, reactive oxygen species (ROS), and cell monolayer permeability were determined. EcN SN in LB medium reduced Caco-2 cell viability significantly, to 51% at 48 h. The combination of this EcN SN and 5-FU further reduced cell viability to 37% at 48 h, compared to 5-FU control. MRS broth and EcN SN in MRS, together with 5-FU, generated significantly lower levels of ROS compared to 5-FU control. However, all 5-FU treatments significantly disrupted the Caco-2 cell barrier compared to control; with no significant differences observed among any of the 5-FU treatments. EcN SNs (LB+) was most effective at decreasing the viability of Caco-2 cells. This could indicate a potential role for this EcN SN in chemoprevention for colon cancer.

Escherichia coli Nissle 1917-derived factors reduce cell death and late apoptosis and increase transepithelial electrical resistance in a model of 5-fluorouracil-induced intestinal epithelial cell damage.

We evaluated the capacity for supernatants (SNs) derived from Escherichia coli Nissle 1917 (EcN), cultured under different growth conditions, to prevent 5-fluorouracil (5-FU)-induced intestinal epithelial cell damage. EcN was cultured in: Luria Bertani (LB) broth, tryptone soya broth (TSB), de Man Rogosa Sharpe (MRS) broth, and M17 broth supplemented with 10% (v/v) lactose solution (M17). Intestinal epithelial cells (IEC-6) were treated with the following EcN SNs: LB(+), TSB(+), MRS(+), and M17(+) in the presence and absence of 5-FU (1.5 or 5 µM). Cell viability, apoptotic activity and cell monolayer permeability were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), flow cytometry, and transepithelial electrical resistance (TER) assays, respectively. 5-FU significantly reduced cell viability (P<0.05) at both 24 and 48 h. However, only EcN SN produced from LB and M17 growth media significantly decreased cell death induced by 5-FU (by approximately 10% after 24 and 48 h; and 10% after 24 h, respectively [P<0.05]). When measured by flow cytometry all EcN SNs in the presence of 5-FU increased the proportion of viable cells (by 3-5% for 24 h, 3-7% for 48 h, P<0.05) and reduced late-apoptotic cells after 24 and 48 h, compared with 5-FU control. Moreover, all EcN SNs significantly reduced the disruption of IEC-6 cell barrier function induced by 5-FU by 7-10% (P<0.05), compared with DMEM control. We conclude that EcN derived factors could potentially reduce the severity of intestinal mucositis.

Effects of Streptococcus thermophilus TH-4 in a rat model of doxorubicin-induced mucositis.

BACKGROUND: Mucositis is a debilitating intestinal side effect of chemotherapeutic regimens. Probiotics have been considered a possible preventative treatment for mucositis. Streptococcus thermophilus TH-4 (TH-4), a newly identified probiotic, has been shown to partially alleviate mucositis induced by administration of the antimetabolite chemotherapy drug, methotrexate in rats; likely mediated through a mechanism of folate production. However, its effects against other classes of chemotherapy drug have yet to be determined. AIMS: The authors investigated the effects of TH-4 in a rat model of mucositis induced by the anthracycline chemotherapy drug, doxorubicin. METHODS: Gastrointestinal damage was induced in female Dark Agouti rats (148.3 ± 1.5 g) by intraperitoneal injection of doxorubicin (20 mg/kg). Animals recieved a daily oral gavage of TH-4 at 10(9) cfu/ml or skim milk (vehicle) from days 0 to 8. At day 6, rats were injected with either saline or doxorubicin. At kill, small intestinal tissues were collected for determination of sucrase and myeloperoxidase (MPO) activities and histological assessment. RESULTS: Body weight was significantly decreased by doxorubicin compared with normal controls (p < 0.05). Histological parameters, such as crypt depth and villus height, were also significantly decreased by doxorubicin. TH-4 partially prevented the loss of body weight induced by doxorubicin (2.3% compared with 4%), but provided no further therapeutic benefit. CONCLUSIONS: The minimal amelioration of doxorubicin-induced mucositis by TH-4 further supports folate production as a likely mechanism of TH-4 action against methotrexate-induced mucositis. Further studies into TH-4 are required to confirm its applicability to other conventional chemotherapy regimens.

Role of endogenous microbiota, probiotics and their biological products in human health.

Although gut diseases such as inflammatory bowel disease, mucositis and the alimentary cancers share similar pathogenetic features, further investigation is required into new treatment modalities. An imbalance in the gut microbiota, breached gut integrity, bacterial invasion, increased cell apoptosis to proliferation ratio, inflammation and impaired immunity may all contribute to their pathogenesis. Probiotics are defined as live bacteria, which when administered in sufficient amounts, exert beneficial effects to the gastrointestinal tract. More recently, probiotic-derived factors including proteins and other molecules released from living probiotics, have also been shown to exert beneficial properties. In this review we address the potential for probiotics, with an emphasis on probiotic-derived factors, to reduce the severity of digestive diseases and further discuss the known mechanisms by which probiotics and probiotic-derived factors exert their physiological effects.

TRH microinjection into DVC enhances motility of rabbits gallbladder via vagus nerve.

AIM:To investigate the effects of TRH in DVC on motility of the gallbladder in rabbits.METHODS:fter fasted for 15h-18h, rabbits were anesthetized with urethane (1.0g/kg).Gallbladder pressure (GP) was measured by a frog bladder perfused with normal saline.RESULTS:After microinjection of TRH (8.8nmol,1&mgr;l) into DVC,GP was raised and the frequency of phasic contraction of gallbladder (FPCGB) increased. All the doses of TRH (0.13, 0.25, 0.50, 0.80, 1.30nmol, 1&mgr;l) injected into DVC could excite the motility of gallblader. As the dose of TRH was enlarged, the amplitude and duration of the reaction increased. Effects of TRH in DVC on motility of the gallbladder could be completely abolished by atropine (0.2mg/g, i.v.) or vagotomy, but could not be inhibited by phentolamine iv (1.5mg/g) or propranolol iv (1.5mg/g)or by transecting the spinal cord.CONCLUSION: Thyrotropin-releasing hormone in DVC can excite motility of gallbladder. This effect was mediated by vagus nerves and peripheral M receptor. Its physiological significance may be related to maintaining the phasic contraction of gallbladder in interdigestive period.

Effects of octreotide on gallbladder pressure and myoelectric activity of Oddi sphincter in rabbits.

AIM:To observe the effect of octreotide (OT) and somatostatin (SS) on gallbladder pressure and myoelectric activity of SO in rabbits.METHODS:Male rabbits fasted for 15h-18h and anesthetized with urethane. The mean gallbladder pressure (GP) and myoelectric activity of SO were simutaneously measured with a frog bladder connected to a transducer and a pair of copper electrodes.RESULTS:After injection of OT (10&mgr;g/kg, iv), the GP decreased in 2min and reached the lowest value in about 60min (P < 0.01, n = 19), and completely or partially returned to the normal level in 120min. The frequency of myoelectric activty of SO was reduced, even disappeared in 2min (P < 0.01, n = 19) and returned to normal in about 20min. Injection of SS (10&mgr;g/kg, iv) also decreased GP and myoelectric activity of SO (P < 0.01, n = 7); Before and after injection of OT or SS, injection of CCK-8 (100ng or 200ng) caused similar increase in myoelectric activity of SO and GP (P >0.05). Before and after injection of OT, there were no significant differences in increases of myoelectric activity of SO and GP caused by electric stimulation of dorsal motor nucleus of vagus (P >0.05).CONCLUSION:OT and SS decreased GP and myoelectric activity of SO, demonstrating that effects of OT were similar to those of SS. Intravenous injection of OT did not affect the increase of myoelectric activity of SO and GP caused by CCK-8 or electric stimulation of dorsal motor nucleus of vagus.