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Mechanism and Role of Probiotics in Suppressing Bowel Cancer
Published in Sheeba Varghese Gupta, Yashwant V. Pathak, Advances in Nutraceutical Applications in Cancer, 2019
Aaishwarya B. Deshmukh, Jayvadan K. Patel, Bharat Mishra
Another mechanism whereby probiotics influence bowel cancer risk is the microbial, that is, bacterial alteration of food components in lumen of intestine and production of cancer-preventive agents. Short-chain fatty acid (SCFA) as well as gas is generated by bacterial fermentation of indigestible carbohydrates. Fecal material eliminates the formed gas, while SCFA, primarily acetate, propionate, and butyrate, correspond to intestinal mucosal nutrients and growth signals by reducing the concentration of secondary bile salts [50]. Convincing study shows that butyrate improves cellular differentiation and diminishes proliferation in bowel cancer cell lines. A specific strain (MDT-1) of the ruminal bacterium Butyrivibrio fibrisolvens creates elevated quantity of butyrate and has been evaluated for use as a probiotic to prevent bowel cancer [51] in a mouse model. The result shows that administration of MDT-1 reduces the amount of ACF and the percentage of mice with enlarged ACF fraction. Nonetheless, synbiotics are more active in escalating the production of SCFA probiotics alone, and therefore protection against bowel cancer onset. Furthermore, probiotics also produce collection of fatty acids known as conjugated linoleic acids (CLAs), which can be considered as set of isomers of linoleic acid, which exerts abundant health benefits, such as anti-inflammatory and anticarcinogenic effects besides SCFA [52]. In rodent studies, reduction in the incidence of colonic tumors has been observed by CLA. All these studies support the notion that fermentation of indigestible food by supplemental probiotics can be a strategy for preventing bowel cancer; however, advanced investigations are required.
The dichotomous role of the gut microbiome in exacerbating and ameliorating neurodegenerative disorders
Published in Expert Review of Neurotherapeutics, 2020
Urdhva Raval, Joyce M. Harary, Emma Zeng, Giulio M. Pasinetti
ALS is a fatal neurodegenerative disorder that involves neurons in the brain and spinal cord. ALS results in muscle weakness and stiffness. ALS eventually leads to difficulty in speech, swallowing, and breathing, ultimately resulting in death due to respiratory paralysis. The cause of Sporadic ALS, the most common type of ALS, remains elusive. In animal models of ALS, leaky gut and disrupted blood brain barrier have been observed [16,89]. Though its etiology is unknown, ALS has been associated with reduced levels of anti-inflammatory bacteria in the gut. Specifically, butyrate producing bacteria, including Butyrivibrio fibrisolvens and Escherichia coli, as well as those of the genus, Oscillibacter, Anaerostipes, and Lachnospira were found to be reduced. Reduction of these butyrate producing bacteria has been linked to increased levels of pro-inflammatory cytokines in the intestine and serum. Additionally, the ratio of the phyla Bacteroidetes to Firmicutes is disrupted in ALS patients when compared to healthy individuals, providing further evidence of GM dysbiosis in ALS pathology [100,101]. GM derived products such as LPS have been found in the plasma of ALS patients and can cross the blood brain barrier to cause neuroinflammation, potentially contributing to ALS pathogenesis [94].
The role of gut microbiota, butyrate and proton pump inhibitors in amyotrophic lateral sclerosis: a systematic review
Published in International Journal of Neuroscience, 2020
Astrid C. Erber, Hakan Cetin, David Berry, Eva S. Schernhammer
Wu et al. [26] examined the gut of SOD1-G93A mice and found that they, in comparison to wild-type (WT) mice, experienced increased gut permeability, damaged tight junction structure and increased numbers of abnormal Paneth cells, a cell type responsible for antimicrobial defense. Investigation of the intestinal microbiome revealed a shifted relative abundance of microbial species such as a reduction of the butyrate-producing Butyrivibrio fibrisolvens.
Mucins, gut microbiota, and postbiotics role in colorectal cancer
Published in Gut Microbes, 2021
Ramesh Pothuraju, Sanjib Chaudhary, Satyanarayana Rachagani, Sukhwinder Kaur, Hemant K. Roy, Michael Bouvet, Surinder K. Batra
According to epidemiologic studies, sporadic CRC can be associated with the diet.29 As shown in Figure 1, a Western-style diet (rich in fat or sucrose, red and processed meat, and low in fiber) alters gut microbiota, and can influence the integrity of the intestinal mucus layer; however, the association between diet, gut microbiota, and mucus layer remain unclear.30 Some of the studies delineating the role of dietary fibers in CRC have reported conflicting results.31 This is due to the source of fiber (cereals vs. fruits) or individuals having a different composition of gut microbiota, variation in the treatment duration, and heterogeneity in tumor subtypes.32 Recently, experts from World Cancer Research Fund and American Institute for Cancer Research in 2017 (https://www.wcrf.org/dietandcancer/colorectal-cancer) reported that consumption of red and processed meat (100 g/day, each) increases the risk of CRC, while intake of whole grains and dairy products (90 and 400 g/day) decreased the risk for CRC.33 Another study, switched mice from chow to a western diet for 28 days and showed an increase in the permeability of the intestine and a decrease in the thickness of the inner mucus layer (especially reducedMuc2 polymeric network). By contrast, supplementing mice with inulin fiber along with Bifidobacterium longum sufficiently restored mucus growth.30 The absence of dietary fiber in gnotobiotic mice (populated with known organisms) increases access of Citrobacter rodentium to the colonic mucus layer, damaging the mucosa and resulting in colitis and eventually CRC. The increase in C. rodentium results in higher expression of carbohydrate-active enzymes that in turn degrade mucins for their energy.17 In contrast to this, colonization of butyrate-producing bacterium Butyrivibrio fibrisolvens in the presence of a high fiber diet (2% cellulose and 6% fructo-oligosaccharide/inulin) protected gnotobiotic mice from CRC development.34