Revisit dietary fiber on colorectal cancer: butyrate and its role on prevention and treatment

Sex Difference of Colon Adenoma Pathway and Colorectal Carcinogenesis

Colorectal cancer (CRC) is one of the most common causes of cancer morbidity in both sexes but shows sex differences. First, sex-specific differences in tumor recurrence and survival rates have been reported. For example, the development of CRC is found about 1.5 times higher and 4-8 years earlier in males compared to females, suggesting the protective role of estrogen in the disease. Furthermore, female patients have a higher risk of developing right-sided (proximal) colon cancer than male patients, which is known to have more aggressive clinical character compared to left-sided (distal) colon cancer. That is, left and right CRCs show differences in carcinogenic mechanism, that the chromosomal instability pathway is more common in left colon cancer while the microsatellite instability and serrated pathways are more common in right colon cancer. It is thought that there are sex-based differences on the background of carcinogenesis of CRC. Sex differences of CRC have two aspects, sexual dimorphism (biological differences in hormones and genes) and gender differences (non-biological differences in societal attitudes and behavior). Recently, sex difference of colon adenoma pathway and sexual dimorphism in the biology of gene and protein expression, and in endocrine cellular signaling in the CRC carcinogenesis have been accumulated. In addition, behavioral patterns can lead to differences in exposure to risk factors such as drinking or smoking, diet and physical activity. Therefore, understanding sex/gender-related biological and sociocultural differences in CRC risk will help in providing strategies for screening, treatment and prevention protocols to reduce the mortality and improve the quality of life. In this review, sex/gender differences in colon adenoma pathway and various aspects such as clinicopathological, biological, molecular, and socio-cultural aspects of CRC were described.

Butyrate's (a short-chain fatty acid) microbial synthesis, absorption, and preventive roles against colorectal and lung cancer

Butyrate, a short-chain fatty acid (SCFA) produced by bacterial fermentation of fiber in the colon, is a source of energy for colonocytes. Butyrate is essential for improving gastrointestinal (GI) health since it helps colonocyte function, reduces inflammation, preserves the gut barrier, and fosters a balanced microbiome. Human colonic butyrate producers are Gram-positive firmicutes, which are phylogenetically varied. The two most prevalent subgroups are associated with Eubacterium rectale/Roseburia spp. and Faecalibacterium prausnitzii. Now, the mechanism for the production of butyrate from microbes is a very vital topic to know. In the present study, we discuss the genes encoding the core of the butyrate synthesis pathway and also discuss the butyryl-CoA:acetate CoA-transferase, instead of butyrate kinase, which usually appears to be the enzyme that completes the process. Recently, butyrate-producing microbes have been genetically modified by researchers to increase butyrate synthesis from microbes. The activity of butyrate as a histone deacetylase inhibitor (HDACi) has led to several clinical trials to assess its effectiveness as a potential cancer treatment. Among various significant roles, butyrate is the main energy source for intestinal epithelial cells, which helps maintain colonic homeostasis. Moreover, people with non-small-cell lung cancer (NSCLC) have distinct gut microbiota from healthy adults and frequently have dysbiosis of the butyrate-producing bacteria in their guts. So, with an emphasis on colon and lung cancer, this review also discusses how the microbiome is crucial in preventing the progression of certain cancers through butyrate production. Further studies should be performed to investigate the underlying mechanisms of how these specific butyrate-producing bacteria can control both colon and lung cancer progression and prognosis.

Dietary fiber (oligosaccharide and non-starch polysaccharide) in preventing and treating functional gastrointestinal disorders - Challenges and controversies: A review

Functional gastrointestinal disorders (FGIDs) are a group of chronic or recurrent gastrointestinal functional diseases, including functional dyspepsia, irritable bowel syndrome, and functional constipation. A lack of safe and reliable treatments for abdominal pain-related FGIDs has prompted interest in new therapies. Evidence has shown that supplementation with dietary fiber may help treat FGIDs. Dietary fibers (DFs) have been demonstrated to have regulatory effects on the gut microbiota, microbiota metabolites, and gastrointestinal movement and have important implications for preventing and treating FGIDs. However, the adverse effects of some DFs, such as fermentable oligosaccharides, on FGIDs are unclear. This review provides an overview of the DFs physiological properties and functional characteristics that influence their use in management of FGIDs, with emphasis on structural modification technology to improve their therapeutic activities. The review highlights that the use of appropriate or novel fibers is a potential therapeutic approach for FGIDs.

Commensal microbiota-derived metabolite agmatine triggers inflammation to promote colorectal tumorigenesis

Colorectal cancer (CRC), a malignant tumor worldwide, is associated with gut microbiota. The influence of gut microbe-derived metabolites on CRC has attracted a lot of attention. However, the role of immunity mediated by commensal microbiota-derived metabolites in tumorigenesis of CRC is not intensively explored. Here we monitored the gut microbial dysbiosis in CRC mouse model (ApcMin/+ model) without dietary and pharmacological intervention, followed by characterized of metabolites enriched in CRC model mice. Profound changes of gut microbiome (bacteriome) were observed during intestinal disorders. Metabolomic profiling indicated that agmatine, derived from the gut bacteria i.e. Blautia, Odoribacter, Alistipes and Paraprevotella, could interact with Rnf128 to suppress the Rnf128-mediated ubiquitination of β-catenin to further upregulate the downstream targets of β-catenin including Cyclin D1, Lgr5, CD44 and C-myc, thus activating Wnt signaling. The activated Wnt signaling pathway promoted dysplasia of intestinal cells and inflammatory infiltration of lymphocytes via inducing the upregulation of pro-inflammatory cytokines (IL-6 and TNF-α) and downregulation of anti-inflammatory cytokine (IL-10), thereby contributing to colorectal carcinogenesis. Therefore, our study presented novel insights into the roles and mechanisms of gut microbiota in pathogenesis of CRC.

Possible cancer-causing capacity of COVID-19: Is SARS-CoV-2 an oncogenic agent?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has shown diverse life-threatening effects, most of which are considered short-term. In addition to its short-term effects, which has claimed many millions of lives since 2019, the long-term complications of this virus are still under investigation. Similar to many oncogenic viruses, it has been hypothesized that SARS-CoV-2 employs various strategies to cause cancer in different organs. These include leveraging the renin angiotensin system, altering tumor suppressing pathways by means of its nonstructural proteins, and triggering inflammatory cascades by enhancing cytokine production in the form of a "cytokine storm" paving the way for the emergence of cancer stem cells in target organs. Since infection with SARS-CoV-2 occurs in several organs either directly or indirectly, it is expected that cancer stem cells may develop in multiple organs. Thus, we have reviewed the impact of coronavirus disease 2019 (COVID-19) on the vulnerability and susceptibility of specific organs to cancer development. It is important to note that the cancer-related effects of SARS-CoV-2 proposed in this article are based on the ability of the virus and its proteins to cause cancer but that the long-term consequences of this infection will only be illustrated in the long run.

Diet-mediated gut microbial community modulation and signature metabolites as potential biomarkers for early diagnosis, prognosis, prevention and stage-specific treatment of colorectal cancer

BACKGROUND

Over the last decade, studies have shown an increased incidence of colorectal cancer (CRC), particularly early onset colorectal cancer (EOCRC). Researchers have demonstrated that dietary behavior, especially among young adults, influences alterations in the gut microbial community, leading to an increased accumulation of pathogenic gut microbiota and a decrease in beneficial ones. Unfortunately, CRC is likely to be diagnosed at a late stage, increasing CRC-related mortality. However, this alteration in the gut microbiota (gut dysbiosis) can be harnessed as a biomarker for non-invasive diagnosis, prognosis, prevention, and treatment of CRC in an effort to prevent late diagnosis and poor prognosis associated with CRC.

AIM OF REVIEW

This review discusses identification of potential biomarkers by targeting diet-mediated gut dysbiosis for the stage-specific diagnosis, prognosis, treatment, and prevention of CRC. Our findings provide a comprehensive insight into the potential of protumorigenic bacteria (e.g.pathogenic Escherichia coli,enterotoxigenic Bacteroides fragilis and Fusobacterium nucleatum) and their metabolites (e.g., colibactin and B. fragilis toxin) from gut dysbiosis as biomarkers for the diagnosis of CRC.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Collectively, a detailed understanding of the available data from current studies suggests that, further research on quantification of metabolites and stage-specific pathogenic microbial abundance is required for the diagnosis and treatment of CRC based on microbial dysbiosis. Specifically, future studies on faecal samples, from patient with CRC, should be conducted for F. nucleatum among different opportunistic bacteria, given its repeated occurrence in faecal samples and CRC biopsies in numerous studies. Finally, we discuss the potential of faecal microbial transplantation (FMT) as an intervention to restore damaged gut microbiota during CRC treatment and management.

Supplementation of quinoa peptides alleviates colorectal cancer and restores gut microbiota in AOM/DSS-treated mice

Quinoa protein hydrolysate has been previously reported to exert anti-cancer effects in cultured colon cancer cells. Here, we investigated the effect of quinoa protein and its hydrolysate on an azoxymethane/dextran sulfate sodium (AOM/DSS)-induced mouse model of colorectal cancer (CRC) and examined its underlying mechanism using gut microbiota analysis and short chain fatty acids (SCFAs) production analysis. Our results showed that quinoa protein or its hydrolysate mitigated the clinical symptoms of CRC and increased SCFAs contents in colon tissues. Moreover, administration of quinoa protein or its hydrolysate partially alleviated gut microbiota dysbiosis in CRC mice by decreasing the abundance of pathogenic bacteria and increasing the abundance of probiotics. Additionally, PICRUSt analysis revealed that the functional profile of gut microbiota in the quinoa protein treated groups was more similar to that of the control group. These findings indicated that the modulation of gut microbiota by quinoa protein diet intervention may ameliorate AOM/DSS-induced CRC.

Dietary and microbiome evidence in multiple myeloma and other plasma cell disorders

Multiple Myeloma (MM) remains an incurable plasma cell neoplasm. Although little is known about the etiology of MM, several metabolic risk factors such as obesity, diabetes mellitus, diet, and the human intestinal microbiome have been linked to the pathogenesis of MM. In this article, we provide a detailed review of dietary and microbiome factors involved in the pathogenesis of MM and their impact on outcomes. Concurrent with treatment advancements that have improved survival in MM, focused efforts are needed to reduce the burden of MM as well as improve MM specific and overall outcomes once MM is diagnosed. The findings presented in this review will provide a comprehensive guide on the evidence available to date of the impact of dietary and other lifestyle interventions on the gut microbiome and on MM incidence, outcomes, and quality of life. Data generated from such studies can help formulate evidence-based guidelines for healthcare providers to counsel individuals at risk such as those with Monoclonal Gammopathy of Undetermined Significance (MGUS) and Smoldering Multiple Myeloma (SMM) as well as MM survivors with respect to their dietary habits.

Metabolomic profiling for the preventive effects of dietary grape pomace against colorectal cancer

Colorectal cancer (CRC) is one of the most common and deadly cancers worldwide. Grape pomace (GP) is a rich source of bioactive compounds with anti-inflammatory, and anticancer effects. We recently found that dietary GP had protective effects against CRC development in the azoxymethane (AOM)/dextran sulfate sodium (DSS) CRC mouse model through suppression of cell proliferation and modulation of DNA methylation. However, the underlying molecular mechanisms associated with changes in metabolites remain unexamined. This study profiled fecal metabolomic changes in a mouse CRC model in response to GP supplementation using gas chromatography-mass spectrometry (GC-MS) based metabolomic analysis. A total of 29 compounds showed significant changes due to GP supplementation, including bile acids, amino acids, fatty acids, phenols/flavonoids, glycerolipids, carbohydrates, organic acids, and others. The major changes in metabolites of feces include increased deoxycholic acid (DCA) and decreased amino acid content. Dietary GP upregulated the expression of farnesoid X receptor (FXR) downstream genes while decreasing fecal urease activity. DNA repair enzyme MutS Homolog 2 (MSH2) was upregulated by GP supplementation. Consistently, γ-H2AX, as a DNA damage marker, decreased in GP supplemented mice. Moreover, MDM2, a protein in the ataxia telangiectasia mutated (ATM) signaling, was decreased by GP supplementation. These data provided valuable metabolic clues for unraveling the protective effects of GP supplementation against CRC development.

Prediction of high fecal propionate-to-butyrate ratios using 16S rRNA-based detection of bacterial groups with liquid array diagnostics

Butyrate and propionate represent two of three main short-chain fatty acids produced by the intestinal microbiota. In healthy populations, their levels are reportedly equimolar, whereas a deviation in their ratio has been observed in various diseased cohorts. Monitoring such a ratio represents a valuable metric; however, it remains a challenge to adopt short-chain fatty acid detection techniques in clinical settings because of the volatile nature of these acids. Here we aimed to estimate short-chain fatty acid information indirectly through a novel, simple quantitative PCR-compatible assay (liquid array diagnostics) targeting a limited number of microbiome 16S markers. Utilizing 15 liquid array diagnostics probes to target microbiome markers selected by a model that combines partial least squares and linear discriminant analysis, the classes (normal vs high propionate-to-butyrate ratio) separated at a threshold of 2.6 with a prediction accuracy of 96%.

Inactivation of the MSTN gene expression changes the composition and function of the gut microbiome in sheep

Background

Myostatin (MSTN) negatively regulates the muscle growth in animals and MSTN deficient sheep have been widely reported previously. The goal of this study was to explore how MSTN inactivation influences their gut microbiota composition and potential functions.

Results

We compared the slaughter parameters and meat quality of 3 MSTN-edited male sheep and 3 wild-type male sheep, and analyzed the gut microbiome of the MSTN-edited sheep (8 female and 8 male sheep) and wild-type sheep (8 female and 8 male sheep) through metagenomic sequencing. The results showed that the body weight, carcass weight and eye muscle area of MSTN-edited sheep were significantly higher, but there were no significant differences in the meat quality indexes. At the microbial level, the alpha diversity was significantly higher in the MSTN-edited sheep (P < 0.05), and the microbial composition was significantly different by PCoA analysis in the MSTN-edited and wild-type sheep. The abundance of Firmicutes significantly increased and Bacteroidota significantly decreased in the MSTN-edited sheep. At genus level, the abundance of Flavonifractor, Subdoligranulum, Ruthenibacterium, Agathobaculum, Anaerotignum, Oribacterium and Lactobacillus were significantly increased in the MSTN-edited sheep (P < 0.05). Further analysis of functional differences was found that the carotenoid biosynthesis was significantly increased and the peroxisome, apoptosis, ferroptosis, N-glycan biosynthesis, thermogenesis, and adipocytokines pathways were decreased in the MSTN-edited sheep (P < 0.05). Moreover, carbohydrate-active enzymes (CAZymes) results certified the abundance of the GH13_39, GH4, GH137, GH71 and PL17 were upregulated, and the GT41 and CBM20 were downregulated in the MSTN-edited sheep (P < 0.05).

Conclusions

Our study suggested that MSTN inactivation remarkably influenced the composition and potential function of hindgut microbial communities of the sheep, and significantly promoted growth performance without affecting meat quality.

Association between Dietary Fiber Intake and Mortality among Colorectal Cancer Survivors: Results from the Newfoundland Familial Colorectal Cancer Cohort Study and a Meta-Analysis of Prospective Studies

Simple Summary

High dietary fiber intake has been linked to a lower risk of Colorectal cancer (CRC), but the role of dietary fiber in CRC survival is understudied. We examined dietary fiber intake for its relevance to CRC survival in a cohort of 504 CRC patients and a meta-analysis including results from four prospective cohort studies. We found that high dietary fiber intake was negatively correlated with all-cause mortality and CRC-specific mortality among CRC survivors. These new findings support the protective effect of dietary fiber on CRC survival. By enhancing fiber intake, this research may contribute to the development of novel therapies that add to our armamentarium for CRC.

Abstract

We examined dietary fiber intake for its relevance to Colorectal cancer (CRC) survival in a cohort of CRC patients and a meta-analysis including results from four prospective cohort studies. We analyzed 504 CRC patients enrolled in the Newfoundland Familial Colorectal Cancer Study (NFCCS) who were newly diagnosed with CRC between 1999 and 2003. Follow-up for deaths was through April 2010. All participants completed a self-administered food frequency questionnaire to evaluate their dietary intakes one year before diagnosis. Multivariable Cox proportional hazard models were used to explore the associations of dietary fiber intake with all-cause mortality and CRC-specific mortality. In the meta-analysis, we identified prospective cohort studies published between January 1991 and December 2021 by searching PubMed, EMBASE, and Cochrane Library. Fixed-effects or random-effects models were used to combine the study-specific hazard ratio (HR) from our original analysis and three other cohorts. In the NFCCS, we found that CRC patients with the second quartile of dietary fiber intake had a 42% lower risk of all-cause mortality (HR: 0.58, 95% CI: 0.35–0.98) and 58% lower risk of CRC-specific mortality (HR: 0.42, 95% CI: 0.21–0.87) compared with those with the lowest quartile. In the meta-analysis, a similar inverse association between dietary fiber and total mortality was detected among CRC patients; each 10 g/day increase in dietary fiber intake was associated with a 16% decreased risk of total mortality. The dose–response meta-analysis showed a linear relationship between dietary fiber intake and all-cause mortality, with no sign of a plateau. For CRC-specific mortality, intriguingly, the benefit associated with increasing dietary fiber intake achieved its maximum at approximately 22 g/day, and no further reduction in CRC-specific mortality was observed beyond this intake level. Our results suggest that high dietary fiber intake may be associated with prolonged survival among CRC patients. Our findings add to the sparse literature on the role of dietary fiber in CRC survival.

Colon Cancer: From Epidemiology to Prevention

Colorectal cancer (CRC) is one of the most prevalent cancers affecting humans, with a complex genetic and environmental aetiology. Unlike cancers with known environmental, heritable, or sex-linked causes, sporadic CRC is hard to foresee and has no molecular biomarkers of risk in clinical use. One in twenty CRC cases presents with an established heritable component. The remaining cases are sporadic and associated with partially obscure genetic, epigenetic, regenerative, microbiological, dietary, and lifestyle factors. To tackle this complexity, we should improve the practice of colonoscopy, which is recommended uniformly beyond a certain age, to include an assessment of biomarkers indicative of individual CRC risk. Ideally, such biomarkers will be causal to the disease and potentially modifiable upon dietary or therapeutic interventions. Multi-omics analysis, including transcriptional, epigenetic as well as metagenomic, and metabolomic profiles, are urgently required to provide data for risk analyses. The aim of this article is to provide a perspective on the multifactorial derailment of homeostasis leading to the initiation of CRC, which may be explored via multi-omics and Gut-on-Chip analysis to identify much-needed predictive biomarkers.

Butyrate emerges as a crucial effector of Zhi-Zi-Chi decoctions to ameliorate depression via multiple pathways of brain-gut axis

Gut microbiota has emerged as a crucial target of gut-brain axis to influence depression. Zhi-Zi-Chi decoctions (ZZCD), as a classic oral formula in clinic, is widely applied in depression treatment nowadays. However, the underlying mechanism in the antidepressant activity of ZZCD remains unknown. A classic depression model of chronic mild unpredictable stress (CUMS) was established in rats based on the results of behavioral tests and hippocampal histomorphology. 16S rRNA sequencing analysis indicated that ZZCD could increase short-chain fatty acid-producing and anti-inflammatory bacteria and reduce inflammatory and tryptophan-metabolizing bacteria. Furthermore, ZZCD reversed the alterations of BDNF, TNF-α, pro-inflammatory cytokines and neurotransmitters in the gut, blood and brain along the brain-gut axis and restored the decrease of butyrate in cecal content caused by CUMS. Then, butyrate was utilized to validate its ameliorative effect on pathological characteristics of depressive rats. Taken together, these results show that ZZCD exhibits antidepressant effect through modulating gut microbiota to facilitate the production of butyrate, which further regulate anti-inflammation, neurotransmitters, endocrine and BDNF along the gut-brain axis. Hence, this study fills the gap of the antidepressive mechanism of ZZCD in the light of the brain-gut axis and established a multi-targets and multi-levels platform eventually for further research into the mechanism of other TCM efficacy.

Hibiscus (Hibiscus sabdariffa L.) supplementation increases butyrate synthesis and reduces inflammatory cells, attenuating the formation of aberrant crypt foci in BALB/c mice induced to pre-neoplastic lesions

The development of colorectal cancer involves some morphological changes, and in the initial stage, pre-neoplastic lesions called aberrant crypt foci (ACF) appear. Thus, an intervention with sources of bioactive compounds such as Hibiscus sabdariffa L., rich in phenolic compounds and anthocyanins, could attenuate the risk of developing these lesions due to its antioxidant, anti-inflammatory and anti-proliferative properties. Therefore, the aim of this study was to evaluate the effects of 5% and 10% supplementation of dehydrated H. sabdariffa calyces (DHSC) during the development of 1,2-dimethylhydrazine-induced preneoplastic lesions in male BALB/c mice. The characterization of DHSC was carried out. The in vivo experiment lasted 12 weeks, and the animals were randomly divided into 3 experimental groups: the control group (CON) and the supplemented groups with 5% DHSC and 10% DHSC. The activities of liver enzymes catalase and superoxide dismutase were determined. In addition, ACF, short chain fatty acids (SCFA), presence of inflammatory infiltrates, goblet cells and leukocytes in the colonic mucosa were quantified. There was a significant reduction in ACF and the presence of inflammatory infiltrates in the colon of animals in groups 5DHSC and 10DHSC. In addition, the 10DHSC group showed an increase in the activity of the catalse enzyme, in the production of butyrate and in the presence of NK cells in the colon, in addition to more hypertrophied goblet cells. Based on these findings, it is suggested that DHSC supplementation may be recommended to attenuate cellular responses in the early stage of preneoplastic lesions.

Altered gut metabolites and microbiota interactions are implicated in colorectal carcinogenesis and can be non-invasive diagnostic biomarkers

BACKGROUND

Gut microbiota contributes to colorectal cancer (CRC) pathogenesis through microbes and their metabolites. The importance of microbiota-associated metabolites in colorectal carcinogenesis highlights the need to investigate the gut metabolome along the adenoma-carcinoma sequence to determine their mechanistic implications in the pathogenesis of CRC. To date, how and which microbes and metabolites interactively promote early events of CRC development are still largely unclear. We aim to determine gut microbiota-associated metabolites and their linkage to colorectal carcinogenesis.

RESULTS

We performed metabolomics and metagenomics profiling on fecal samples from 386 subjects including 118 CRC patients, 140 colorectal adenomas (CRA) patients and 128 healthy subjects as normal controls (NC). We identified differences in the gut metabolite profiles among NC, CRA and CRC groups by partial least squares-discriminant and principal component analyses. Among the altered metabolites, norvaline and myristic acid showed increasing trends from NC, through CRA, to CRC. CRC-associated metabolites were enriched in branched-chain amino acids, aromatic amino acids and aminoacyl-tRNA biosynthesis pathways. Moreover, metabolites marker signature (twenty metabolites) classified CRC from NC subjects with an area under the curve (AUC) of 0.80, and CRC from CRA with an AUC of 0.79. Integrative analyses of metabolomics and metagenomics profiles demonstrated that the relationships among CRC-associated metabolites and bacteria were altered across CRC stages; certain associations exhibited increasing or decreasing strengths while some were reversed from negative to positive or vice versa. Combinations of gut bacteria with the metabolite markers improved their diagnostic performances; CRC vs NC, AUC: 0.94; CRC vs CRA, AUC 0.92; and CRA vs NC, AUC: 0.86, indicating a potential for early diagnosis of colorectal neoplasia.

CONCLUSIONS

This study underscores potential early-driver metabolites in stages of colorectal tumorigenesis. The Integrated metabolite and microbiome analysis demonstrates that gut metabolites and their association with gut microbiota are perturbed along colorectal carcinogenesis. Fecal metabolites can be utilized, in addition to bacteria, for non-invasive diagnosis of colorectal neoplasia. Video Abstract.

KIAA1429 is a potential prognostic marker in colorectal cancer by promoting the proliferation via downregulating WEE1 expression in an m6A-independent manner

N6-methyladenosine (m6A), the most abundant mRNA modification in mammals, is involved in the metabolism of mRNA. KIAA1429 is regarded as the largest m6A methyltransferase and plays an important role in m6A modification. However, the prognostic value and function of KIAA1429 in colorectal cancer (CRC) are unclear. Quantitative real-time PCR and immunohistochemical assays were performed to evaluate the expression of KIAA1429 in CRC tissues. Kaplan-Meier survival curves and log-rank tests were used to assess the association between KIAA1429 expression and the prognosis of patients with CRC. CCK-8 assays, colony formation assays, cell cycle assays, and xenograft experiments were performed to investigate the effect of KIAA1429 on cell proliferation. RNA immunoprecipitation, methylated RNA immunoprecipitation assays, and RNA stability assays were conducted to explore the underlying mechanism. KIAA1429 was significantly upregulated in CRC tissues compared with adjacent normal tissues. Patients with higher expression of KIAA1429 had shorter overall survival than those with lower expression. Functionally, KIAA1429 promoted CRC cell proliferation in vitro and in vivo. Mechanistically, KIAA1429 negatively regulated the expression of WEE1 by decreasing its stability in an m6A-independent manner by binding to the third segment in the 3'-UTR of WEE1 mRNA. Moreover, butyrate decreased the expression of KIAA1429 by downregulating the level of the transcription factor NFκB1. Our findings indicated that KIAA1429 plays an oncogenic role in CRC cells by inhibiting the expression of WEE1 in an m6A-independent manner and is associated with poor survival in CRC patients. These results suggested that KIAA1429 might be a potential prognostic marker for CRC.

Microenvironmental Factors Modulating Tumor Lipid Metabolism: Paving the Way to Better Antitumoral Therapy

Metabolic reprogramming is one of the emerging hallmarks of cancer and is driven by both the oncogenic mutations and challenging microenvironment. To satisfy the demands of energy and biomass for rapid proliferation, the metabolism of various nutrients in tumor cells undergoes important changes, among which the aberrant lipid metabolism has gained increasing attention in facilitating tumor development and metastasis in the past few years. Obstacles emerged in the aspect of application of targeting lipid metabolism for tumor therapy, due to lacking of comprehensive understanding on its regulating mechanism. Tumor cells closely interact with stromal niche, which highly contributes to metabolic rewiring of critical nutrients in cancer cells. This fact makes the impact of microenvironment on tumor lipid metabolism a topic of renewed interest. Abundant evidence has shown that many factors existing in the tumor microenvironment can rewire multiple signaling pathways and proteins involved in lipid metabolic pathways of cancer cells. Hence in this review, we summarized the recent progress on the understanding of microenvironmental factors regulating tumor lipid metabolism, and discuss the potential of modulating lipid metabolism as an anticancer approach.

Association of circulating short chain fatty acid levels with colorectal adenomas and colorectal cancer

BACKGROUND & AIMS

Short chain fatty acid (SCFAs) are bacterially derived metabolites suggested to have protective roles against colorectal cancer (CRC) development. However, there is sparse evidence from epidemiological studies in this context. Here, we assessed whether circulating SCFA concentrations varied in patients with colorectal adenomas (CRA) and CRC.

METHODS

Levels of seven SCFAs were extracted from plasma samples and determined by gas chromatography for 213 individuals from Ireland and the Czech Republic (CRC, n = 84; CRA, n = 66; controls, n = 63).

RESULTS

In the Irish CRA/CRC cohort, only levels of 2-MethylButyric acid were significantly higher in cancers compared to the adenoma and control groups (p-values = 0.016 and 0.043). Using regression analysis, we observed that levels of Acetic and Propionic acid were associated with an increased CRC risk in the Czech cohort (Odd Ratio (OR): 1.02; 95% Confidence interval (CI): 1.00-1.03; OR: 1.29; 95% CI: 1.05-1.59, respectively), while i-Valeric and Valeric acid levels were associated with a decreased cancer risk (OR: 0.92; 95% CI: 0.86-0.99; OR: 0.67; 95% CI: 0.44-1.00). In the Irish cohort, levels of SCFAs were not associated with CRC risk.

CONCLUSIONS

The association with colorectal neoplasia varied between the studied SCFAs. Future studies need to confirm these findings and address the mechanism of how these acids may promote or prevent colorectal carcinogenesis.

Progress in understanding of relationship between short chain fatty acids and irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional intestinal disease whose pathogenesis has not yet been fully defined. The main clinical manifestations of IBS are irregular abdominal pain, abdominal distension, and changes in stool character and defecation habits. As one of the pathogeneses of IBS, intestinal flora imbalance plays an important role in the development of IBS. The vast majorities of short chain fatty acids (SCFAs) are produced through the interaction of intestinal flora with host diet in the colon. As one of the main metabolites of intestinal flora, SCFAs have the effects of intestinal barrier protection, immune regulation, anti-inflammation, and regulation of visceral sensitivity in the intestine. In recent years, with the increasing attention to SCFAs, studies on the relationship between SCFAs and IBS are emerging. This review summarizes the progress in the understanding of the relationship between SCFAs and IBS in recent five years.

Genome-wide DNA methylation profiling and gut flora analysis in intestinal polyps patients

BACKGROUND

The intestinal polyp is the precancerous lesion of colorectal cancer. DNA methylation and intestinal microbiota may play an important role in the development of intestinal polyp.

MATERIALS AND METHODS

In this study, we included 10 patients with intestinal polyps who received the colonoscopy examination. We applied the Illumina Human Methylation 850K array to investigate the epigenome-wide DNA methylation patterns. Then, we filtered out the hub genes in the protein-protein interaction networks using functional epigenetic modules analysis. We also analyzed the colonizing bacteria on the surface of polyps compared with those in normal colonic mucosal epithelium with 16S ribosomal DNA sequencing.

RESULTS

We identified 323 hypermethylated sites and 7992 hypomethylated sites between intestinal polyps and normal samples. Five hub genes, including CREB1, LPA, SVIL and KRT18, were identified in five modules. Hypomethylation of CREB1 is a candidate marker of colorectal adenoma. Gut microbiota analysis showed that Butyricicoccus was significantly decreased in the intestinal polyp groups.

CONCLUSION

In conclusion, we identified DNA methylation disparities in intestinal polyps compared with normal tissue, of which methylation of CREB1 may hold clinical significance in colorectal cancer progress. Colonizing bacteria in the colonic epithelium might be related to the formation of intestinal polyps.

Roles of Sex Hormones and Gender in the Gut Microbiota

The distribution of gut microbiota varies according to age (childhood, puberty, pregnancy, menopause, and old age) and sex. Gut microbiota are known to contribute to gastrointestinal (GI) diseases such as irritable bowel syndrome, inflammatory bowel disease, and colon cancer; however, the exact etiology remains elusive. Recently, sex and gender differences in GI diseases and their relation to gut microbiota has been suggested. Furthermore, the metabolism of estrogen and androgen was reported to be related to the gut microbiome. As gut microbiome is involved in the excretion and circulation process of sex hormones, the concept of “microgenderome” indicating the role of sex hormone on the gut microbiota has been suggested. However, further research is needed for this concept to be universally accepted. In this review, we summarize sex- and gender-differences in gut microbiota and the interplay of microbiota and GI diseases, focusing on sex hormones. We also describe the metabolic role of the microbiota in this regard. Finally, current subjects, such as medication including probiotics, are briefly discussed.

SARS-CoV-2-Induced Gut Microbiome Dysbiosis: Implications for Colorectal Cancer

The emergence of a novel coronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), in December 2019 led to a worldwide pandemic with over 170 million confirmed infections and over 3.5 million deaths (as of May 2021). Early studies have shown higher mortality rates from SARS-CoV-2 infection in cancer patients than individuals without cancer. Herein, we review the evidence that the gut microbiota plays a crucial role in health and has been linked to the development of colorectal cancer (CRC). Investigations have shown that SARS-CoV-2 infection causes changes to the gut microbiota, including an overall decline in microbial diversity, enrichment of opportunistic pathogens such as Fusobacterium nucleatum bacteremia, and depletion of beneficial commensals, such as the butyrate-producing bacteria. Further, these changes lead to increased colonic inflammation, which leads to gut barrier disruption, expression of genes governing CRC tumorigenesis, and tumor immunosuppression, thus further exacerbating CRC progression. Additionally, a long-lasting impact of SARS-CoV-2 on gut dysbiosis might result in a greater possibility of new CRC diagnosis or aggravating the condition in those already afflicted. Herein, we review the evidence relating to the current understanding of how infection with SARS-CoV-2 impacts the gut microbiota and the effects this will have on CRC carcinogenesis and progression.

Gut microbial metabolites facilitate anticancer therapy efficacy by modulating cytotoxic CD8+ T cell immunity

Recent studies in both mice and humans have suggested that gut microbiota could modulate tumor responsiveness to chemo- or immunotherapies. However, the underlying mechanism is not clear yet. Here, we found that gut microbial metabolites, especially butyrate, could promote the efficacy of oxaliplatin by modulating CD8⁺ T cell function in the tumor microenvironment. Butyrate treatment directly boosted the antitumor cytotoxic CD8⁺ T cell responses both in vitro and in vivo in an ID2-dependent manner by promoting the IL-12 signaling pathway. In humans, the oxaliplatin responder cancer patients exhibited a higher amount of serum butyrate than did non-responders, which could also increase ID2 expression and function of human CD8⁺ T cells. Together, our findings suggest that the gut microbial metabolite butyrate could promote antitumor therapeutic efficacy through the ID2-dependent regulation of CD8⁺ T cell immunity, indicating that gut microbial metabolites could be effective as a part of cancer therapy.

Importance of the Microbiota Inhibitory Mechanism on the Warburg Effect in Colorectal Cancer Cells

METHODS AND RESULTS

Colorectal cancer (CRC) is the third most common cancer in the world. Genetic backgrounds, lifestyle, and diet play an important role in CRC risk. The human gut microbiota has an influence on many features of human physiology such as metabolism, nutrient absorption, and immune function. Imbalance of the microbiota has been implicated in many disorders including CRC. It seems Warburg effect hypothesis corresponds to the early beginning of carcinogenesis because of eventual failure in the synthesis of a pyruvate dehydrogenase complex in cooperation with a supply of glucose in carbohydrates rich diets. From investigation among previous publications, we attempted to make it clear importance of Warburg effect in tumors; it also discusses the mechanisms of probiotics in inhibiting tumor progression and reverse Warburg effect of probiotics in modulating the microbiota and CRC therapies. These effects were observed in some clinical trials, the application of probiotics as a therapeutic agent against CRC still requirements further investigation.

CONCLUSION

Fiber is fermented by colonic bacteria into SCFAs such as butyrate/acetate, which may play a vital role in normal homeostasis by promoting turnover of the colonic epithelium. Butyrate enters the nucleus and functions as a histone deacetylase inhibitor (HDACi). Because cancerous colonocytes undertake the Warburg effect pathway, their favored energy source is glucose instead of butyrate. Therefore, accumulation of moderate concentrations of butyrate in cancerous colonocytes and role as HDACi. Probiotics have been shown to play a protective role against cancer development by modulating intestinal microbiota and immune response.

Butyrate in Energy Metabolism: There Is Still More to Learn

Butyrate, a main product of gut microbial fermentation, has been recognized as an important mediator of gut microbiota regulation in whole body energy homeostasis. However, the mechanisms of butyrate metabolic control remain unclear. This review summarizes studies that directly examined the effects of butyrate on metabolic health. The effects of butyrate on metabolic functions, including thermogenesis, lipid and glucose metabolism, appetite, inflammation, and influence on gut microbiota, are described. The effects of butyrate on cellular systems via G protein-coupled receptors (GPRs), as a histone deacetylase inhibitor, and as a substrate that is metabolized intercellularly, are also discussed. Hopefully, a better understanding of butyrate metabolic regulation may provide new perspectives for the nutritional prevention and treatment of metabolic diseases.

Sodium butyrate protects against lipopolysaccharide-induced liver injury partially via the GPR43/ β-arrestin-2/NF-κB network

Background

Butyrate acts as a regulator in multiple inflammatory organ injuries. However, the role of butyrate in acute liver injury has not yet been fully explored. In the present study, we aimed to investigate the association between butyrate and lipopolysaccharide (LPS)-induced acute liver injury and the signaling pathways involved.

Methods

LPS-induced acute liver injury was induced by intraperitoneal injection of LPS (5 mg/kg) in G-protein-coupled receptor 43 (GPR43)-knockout (KO) and wild-type female C57BL/6 mice. Sodium butyrate (500mg/kg) was administered intraperitoneally 30 min prior to LPS exposure. Liver injury was detected by serum markers, tissue morphology, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). Pro-inflammatory-factor levels were detected by enzyme-linked immunosorbent assay and real-time polymerase chain reaction (RT-PCR). Cell models were first treated with sodium butyrate (4 μmol/mL), followed by LPS (1 μg/mL) half an hour later in GPR43 small interfering RNA (siRNA)-transfected or control RAW264.7 cells. Cell-inflammation status was evaluated through detecting pro-inflammatory-factor expression by RT-PCR and also through checking toll-like receptor 4/nuclear factor-κB (TLR4/NF-κB)-element levels including TLR4, TRAF6, IKKβ, IкBα, phospho-IкBα, p65, and phospho-p65 by Western blot. The interaction between GPR43 and β-arrestin-2 was tested by co-immunoprecipitation.

Results

Sodium butyrate reversed the LPS-induced tissue-morphology changes and high levels of serum alanine aminotransferase, aspartate transaminase, myeloperoxidase, TUNEL, and pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin-6. The ameliorating effect of sodium butyrate was weakened in GPR43-KO mice and GPR43 siRNA RAW264.7 cells, compared with those of GPR43-positive controls. Sodium butyrate downregulated some elements of the TLR4/NF-κB pathway, including phospho-IκBα and phospho-p65, in RAW264.7 cells. Increased interactions between GPR43 and β-arrestin-2, and between β-arrestin-2 and IкBα were observed.

Conclusion

Sodium butyrate significantly attenuated LPS-induced liver injury by reducing the inflammatory response partially via the GPR43/β-arrestin-2/NF-κB signaling pathway.

Cancer burden in China: trends, risk factors and prevention

As the most populous country in the world, China has made strides in health promotion in the past few decades. With the aging population, the burden of cancer in China continues to grow. Changes in risk factors for cancer, especially diet, obesity, diabetes, and air pollution, continue to fuel the shift of cancer transition in China. The burden of upper gastrointestinal cancer in China is decreasing, but still heavy. The rising burden of colorectal, prostate, and breast cancers is also significant. Lung cancer became the top cause of cancer-related deaths, together with smoking as the most important contributor to cancer deaths. The Chinese government has taken several approaches to control cancer and cancer-related risk factors. Many achievements have been made, but some challenges remain. Health China 2030 is ambitious and depicts a bright vision of the future for cancer control in China. The decrease in the cancer burden in China will require cross-sector collaboration and coordinated efforts on primary and secondary preventions by governments, public health organizations, and individuals. In this review, we describe the trends of cancer burden and discuss cancer-related risk factors in China, identifying strategies to reduce the burden of cancer in China.

The Interplay between Fe3O4 Superparamagnetic Nanoparticles, Sodium Butyrate, and Folic Acid for Intracellular Transport

Combined treatments which use nanoparticles and drugs could be a synergistic strategy for the treatment of a variety of cancers to overcome drug resistance, low efficacy, and high-dose-induced systemic toxicity. In this study, the effects on human colon adenocarcinoma cells of surface modified Fe₃O₄ magnetic nanoparticles (MNPs) in combination with sodium butyrate (NaBu), added as a free formulation, were examined demonstrating that the co-delivery produced a cytotoxic effect on malignant cells. Two different MNP coatings were investigated: a simple polyethylene glycol (PEG) layer and a mixed folic acid (FA) and PEG layer. Our results demonstrated that MNPs with FA (FA-PEG@MNPs) have a better cellular uptake than the ones without FA (PEG@MNPs), probably due to the presence of folate that acts as an activator of folate receptors (FRs) expression. However, in the presence of NaBu, the difference between the two types of MNPs was reduced. These similar behaviors for both MNPs likely occurred because of the differentiation induced by butyrate that increases the uptake of ferromagnetic nanoparticles. Moreover, we observed a strong decrease of cell viability in a NaBu dose-dependent manner. Taking into account these results, the cooperation of multifunctional MNPs with NaBu, taking into consideration the particular cancer-cell properties, can be a valuable tool for future cancer treatment.

Gut microbes from the phylogenetically diverse genus Eubacterium and their various contributions to gut health

Over the last two decades our understanding of the gut microbiota and its contribution to health and disease has been transformed. Among a new 'generation' of potentially beneficial microbes to have been recognized are members of the genus Eubacterium, who form a part of the core human gut microbiome. The genus consists of phylogenetically, and quite frequently phenotypically, diverse species, making Eubacterium a taxonomically unique and challenging genus. Several members of the genus produce butyrate, which plays a critical role in energy homeostasis, colonic motility, immunomodulation and suppression of inflammation in the gut. Eubacterium spp. also carry out bile acid and cholesterol transformations in the gut, thereby contributing to their homeostasis. Gut dysbiosis and a consequently modified representation of Eubacterium spp. in the gut, have been linked with various human disease states. This review provides an overview of Eubacterium species from a phylogenetic perspective, describes how they alter with diet and age and summarizes its association with the human gut and various health conditions.

Breast Cancer: A Lifestyle Medicine Approach

Breast cancer is the most common female cancer diagnosis in the United States (excluding skin cancers), and the second leading cause of female cancer death. This article highlights the role that lifestyle plays in primary breast cancer prevention, breast cancer treatment, and tertiary breast cancer prevention. Current data regarding the benefits of a predominantly plant-based diet in combination with physical activity and maintenance of a healthy body weight will be reviewed. The evidenced-based patient-focused recommendations developed by the World Cancer Research Fund/American Institute for Cancer Research will be discussed in the context of an overall lifestyle strategy. It is our hope that this publication empowers clinicians to provide patients with personalized cancer-protective lifestyle prescriptions.

Microbial Community Dynamics During the Non-filamentous Fungi Growth-Based Fermentation Process of Miang, a Traditional Fermented Tea of North Thailand and Their Product Characterizations

Miang, a traditional fermented tea leaf (Camellia sinensis var. assamica) consumed in northern Thailand, was simulated in laboratory conditions using non-filamentous fungi process (NFP) and microbial community was periodically investigated for over 6 months of fermentation by both culture-dependent and -independent techniques. The viable cell numbers of lactic acid bacteria (LAB), yeast, and Bacillus enumerated by the culture-dependent technique markedly surged over 3 days of initial fermentation and then smoothly declined by the end of fermentation. LAB were found as the main microbial population throughout the fermentation period followed by yeast and Bacillus. High-throughput sequencing of microbial community during fermentation revealed that Firmicutes (86.9-96.0%) and Proteobacteria (4.0-12.4%) were the dominant bacterial phyla, whereas Ascomycota was found to be the main fungal phylum with an abundance of over 99% in the fungal community. The dominant bacterial family was Lactobacillaceae (39.7-79.5%) followed by Acetobacteraceae, Enterobacteriaceae, Bacillaceae, Aeromonadaceae, Staphylococcaceae, Moraxellaceae, Clostridiaceae, Exiguobacteraceae, Streptococcaceae, and Halomonadaceae. Meanwhile, the main fungal family was incertae sedis Saccharomycetales (75.6-90.5%) followed by Pichiaceae, Pleosporaceae, Botryosphaeriaceae, Davidiellaceae, Mycosphaerellaceae, and Saccharomycodaceae. In addition, Lactobacillus (29.2-77.2%) and Acetobacter (3.8-22.8%), and the unicellular fungi, Candida (72.5-89.0%) and Pichia (8.1-14.9%), were the predominant genera during the fermentation process. The profiles of physical and chemical properties such as Miang texture, pH, organic acids, polysaccharide-degrading enzyme activities, and bioactive compounds have rationally indicated the microbial fermentation involvement. β-Mannanase and pectinase were assumed to be the key microbial enzymes involved in the Miang fermentation process. Total tannin and total polyphenol contents were relatively proportional to the antioxidant activity. Lactic acid and butyric acid reached maximum of 50.9 and 48.9 mg/g dry weight (dw) at 9 and 63 days of fermentation, respectively. This study provided essential information for deeper understanding of the Miang fermentation process based on the chemical and biological changes during production.

Effects of Short-Chain Fatty Acids on Human Oral Epithelial Cells and the Potential Impact on Periodontal Disease: A Systematic Review of In Vitro Studies

Short-chain fatty acids (SCFA), bacterial metabolites released from dental biofilm, are supposed to target the oral epithelium. There is, however, no consensus on how SCFA affect the oral epithelial cells. The objective of the present study was to systematically review the available in vitro evidence of the impact of SCFA on human oral epithelial cells in the context of periodontal disease. A comprehensive electronic search using five databases along with a grey literature search was performed. In vitro studies that evaluated the effects of SCFA on human oral epithelial cells were eligible for inclusion. Risk of bias was assessed by the University of Bristol's tool for assessing risk of bias in cell culture studies. Certainty in cumulative evidence was evaluated using GRADE criteria (grading of recommendations assessment, development, and evaluation). Of 3591 records identified, 10 were eligible for inclusion. A meta-analysis was not possible due to the heterogeneity between the studies. The risk of bias across the studies was considered "serious" due to the presence of methodological biases. Despite these limitations, this review showed that SCFA negatively affect the viability of oral epithelial cells by activating a series of cellular events that includes apoptosis, autophagy, and pyroptosis. SCFA impair the integrity and presumably the transmigration of leucocytes through the epithelial layer by changing junctional and adhesion protein expression, respectively. SCFA also affect the expression of chemokines and cytokines in oral epithelial cells. Future research needs to identify the underlying signaling cascades and to translate the in vitro findings into preclinical models.

Hospital-Based Preliminary Observations of Dietary Intake and Physical Activity in Saudi Patients with Colorectal Polyps: A Call for Nutrition Care Integration after Polypectomy Procedure

Aim: In Saudi Arabia, the incidence of colorectal cancer (CRC) is increasing. Lifestyle modification, including diet and physical activity, is as important as the standard procedure of colonoscopy screening in reducing CRC development. I explored the dietary intake, physical activity, and selected nutritional biomarkers in Saudi patients with colorectal polyps, a precursor of CRC. Methods: Thirty polypectomy patients (aged 35–84 years) were recruited from an endoscopy unit at King Abdulaziz University Hospital. Demographic, anthropometric, physical activity, and food frequency data were collected. Plasma C-reactive protein, serum 25-hydroxy vitamin D, and folate levels were measured. Results: The median body mass index (BMI) of the patients was within the overweight cut-off range. The median consumption of carbohydrate and protein was within the recommended dietary allowance (RDA). Median fat consumption was above the RDA, while median fiber intake was below the RDA. Patients met the recommended servings/day of fruits, vegetables, dairy products, and protein but exceeded the recommended intake of fats and sweets. Most patients were non-active, with an inadequate level of serum vitamin D. Conclusion: We observed several risk factors previously associated with CRC, including low levels of physical activity, serum vitamin D, and fiber intake, and high BMI and fat intake among polypectomy patients.

Non-Digestible Carbohydrate and the Risk of Colorectal Neoplasia: A Systematic Review

Non-digestible carbohydrate (NDC) is a fiber that can be fermented into short chain fatty acids (SCFAs) in gut, represented by resistant starch (RS) and inulin. Colorectal cancer (CRC) is one of the most common malignant cancer. Pre-clinical studies have reported that NDC can produce SCFAs to protect the gut epithelium, which is associated with prevention of CRC, but this role in clinical trails is controversial. In this review, we discusses whether RS and inulin should be offered to cancer/precancerous patients or healthy subjects to decrease their risk of CRC. A multiple database search was conducted for studies published on RS/inulin supplementation as a chemopreventive method from 1989 to 2019. The meta-analysis showed the total SCFAs and butyrate concentrations (P = 0.84; P = 0.79), and excretions (P = 0.55; P = 0.63) in feces did not increase significantly after RS/inulin supplementation. Only two studies reported that RS/inulin inhibit the proliferation of large bowel epithelial, whereas 15 studies showed that it does not decrease the risk of neoplasia. RS/inulin restored the promotion of tumor risk factors in two studies and did not in four studies. Notably, the other four studies showed that RS increases pro-tumorigenesis mechanisms. The clinical evidences consistently show that RS/inulin is ineffective for preventing colorectal neoplasia.

Adherence to the Saudi dietary guidelines and its relation to colorectal polyps: A university hospital-based study

Objectives

Colorectal polyps are a known precursor to colorectal cancer (CRC). Using the Saudi dietary guidelines adherence scores, this study evaluated whether dietary intake can lead to the development of colorectal polyps in a Saudi cohort.

Methods

In a cross-sectional study, 101 patients of both sexes, aged 30-86 years (40 patients with colorectal polyps and 61 patients without polyps), were recruited from the endoscopy unit in a Saudi hospital. A questionnaire was administered to collect demographic data, anthropometric data, and information about dietary habits.

Results

Patients with colorectal polyps were significantly older than those without polyps (p = 0.05). The mean body mass index in both patient groups was within the overweight range, with a value of 28.6 ± 6.7 kg/m². We did not find significant differences between patients with and without colorectal polyps. Although there was no difference in the overall scores for adherence to the Saudi dietary guidelines between the two groups, the specific adherence score for vegetables was significantly higher in patients without colorectal polyps (5.0 ± 0.0 vs. 4.9 ± 0.3, p = 0.03).

Conclusion

Ageing and lower vegetable intake, previously reported to be risk factors for CRC, were likewise identified in this study. However, a multi-centre study with a larger sample size, utilising data from this study, is needed.

The interplay between dietary factors, gut microbiome and colorectal cancer: a new era of colorectal cancer prevention

Colorectal cancer is the third most common cancer in the world and its incidence is on the rise. Dietary intervention has emerged as an attractive strategy to curtail its occurrence and progression. Diet is known to influence the gut microbiome, as dietary factors and gut bacteria can act in concert to cause or protect from colorectal cancer. Several studies have presented evidence for such interactions and have pointed out the different ways by which the diet and gut microbiome can be altered to produce beneficial effects. This review article aims to summarize the interrelationship between diet, gut flora and colorectal cancer so that a better preventive approach can be applied.

Gastrointestinal Microbiome - What We Need to Know in Clinical Practice

Human gut microbiota plays an important role in individual health. When the balance between host and gut microbiota is disrupted, changes in microbiota composition and function occur, which is referred as dysbiosis. Environmental factors as diet, proton pump inhibitors, and antibiotics can lead to a permanent dysbiotic disruption. Clarification of these imbalances was made possible by recent advances in genome sequencing methods that supported acknowledgment of the interplay between microbiome and intestinal and extraintestinal disorders. This review focuses on the microbiota impact in inflammatory bowel disease, gastric cancer, colorectal cancer, nonalcoholic fatty liver disease (NAFLD), irritable bowel syndrome (IBS), and Clostridium difficile infection (CDI). Furthermore, novel therapies are summarized. Fecal microbiota transplant (FMT) is a successful and established therapy in recurrent CDI, and its application in other dysbiosis-related diseases is attracting enormous interest. Pre- and probiotics target microbial rebalance and have positive effects mainly in NAFLD, ulcerative colitis, IBS, and CDI patients. Promising anticarcinogenic effects have also been demonstrated in animal models. The literature increasingly describes microbial changes in many dysbiotic disorders and shows what needs to be treated. However, probiotics and FMT application in clinical practice suffers from a shortage of randomized controlled trials with standardized therapy regimens to support their recommendation.

Heat-shock transcription factor 2 promotes sodium butyrate-induced autophagy by inhibiting mTOR in ulcerative colitis

Butyrate-induced autophagy and anti-inflammatory effects of IECs plays an important role in UC. HSP has been proved to be associated with autophagy. HSF2, as an important regulator of HSP, has been determined to be highly expressed in UC. This study was designed to elucidate the relationship between HSF2, butyrate and epithelial autophagy and the potential mechanism of HSF2-related autophagy in UC. The autophagy levels and HSF2 expression in intestinal mucosa were increased in UC patients compared to controls. In DSS colitis models, hsf2^-/- mice exhibited more severe intestinal inflammation and lower autophagy levels than wild-type mice. HSF2 expression could be induced by sodium butyrate and LPS as a dose-response relationship in HT-29 cells, epigenetically via increasing histone acetylation levels at the promoter region by sodium butyrate. Autophagy induced by sodium butyrate was promoted by overexpression HSF2 in HT-29 cells. Moreover, overexpression HSF2 decreased the expression and phosphorylation levels of PI3K, Akt and mTOR induced by sodium butyrate. HSF2 might induced by sodium butyrate and inflammation and played protective roles in UC by enhancing autophagy of IECs. This indicated that HSF2 may be a critical target for autophagy modulation and a new potential therapeutic target in UC.

Dietary Fatty Acids and Microbiota-Brain Communication in Neuropsychiatric Diseases

The gut-brain axis is a multimodal communication system along which immune, metabolic, autonomic, endocrine and enteric nervous signals can shape host physiology and determine liability, development and progression of a vast number of human diseases. Here, we broadly discussed the current knowledge about the either beneficial or deleterious impact of dietary fatty acids on microbiota-brain communication (MBC), and the multiple mechanisms by which different types of lipids can modify gut microbial ecosystem and contribute to the pathophysiology of major neuropsychiatric diseases (NPDs), such as schizophrenia (SCZ), depression and autism spectrum disorders (ASD).

The Potential for Plant-Based Diets to Promote Health Among Blacks Living in the United States

Plant-based diets are associated with reduced risks of various chronic diseases in the general population. However, it is unclear how these benefits translate to Blacks living in the United States, who are disproportionately burdened with heart disease, cancer, diabetes, obesity, and chronic kidney disease. The objectives of this study were to: (1) review the general evidence of plant-based diets and health outcomes; (2) discuss how this evidence translates to Blacks following a plant-based diet; and (3) provide recommendations and considerations for future studies in this area. Interestingly, although the evidence supporting plant-based diets in the general population is robust, little research has been done on Blacks specifically. However, the available data suggests that following a plant-based diet may reduce the risk of heart disease and possibly cancer in this population. More research is needed on cardiovascular disease risk factors, cancer subtypes, and other chronic diseases. Further, attention must be given to the unique individual, familial, communal, and environmental needs that Blacks who follow plant-based diets may have. Interventions must be culturally appropriate in order to achieve long-term success, and providing low-cost, flavorful, and nutritious options will be important.

Microbiome, Autoimmune Diseases and HIV Infection: Friends or Foes?

Several studies highlighted the importance of the interaction between microbiota and the immune system in the development and maintenance of the homeostasis of the human organism. Dysbiosis is associated with proinflammatory and pathological state-like metabolic diseases, autoimmune diseases and HIV infection. In this review, we discuss the current understanding of the possible role of dysbiosis in triggering and/or exacerbating symptoms of autoimmune diseases and HIV infection. There are no data about the influence of the microbiome on the development of autoimmune diseases during HIV infection. We can hypothesize that untreated patients may be more susceptible to the development of autoimmune diseases, due to the presence of dysbiosis. Eubiosis, re-established by probiotic administration, can be used to reduce triggers for autoimmune diseases in untreated HIV patients, although clinical studies are needed to evaluate the role of the microbiome in autoimmune diseases in HIV patients.

Epigenetic Gene Regulation by Dietary Compounds in Cancer Prevention

Traditionally, cancer has been viewed as a set of diseases that are driven by the accumulation of genetic mutations, but we now understand that disruptions in epigenetic regulatory mechanisms are prevalent in cancer as well. Unlike genetic mutations, however, epigenetic alterations are reversible, making them desirable therapeutic targets. The potential for diet, and bioactive dietary components, to target epigenetic pathways in cancer is now widely appreciated, but our understanding of how to utilize these compounds for effective chemopreventive strategies in humans is in its infancy. This review provides a brief overview of epigenetic regulation and the clinical applications of epigenetics in cancer. It then describes the capacity for dietary components to contribute to epigenetic regulation, with a focus on the efficacy of dietary epigenetic regulators as secondary cancer prevention strategies in humans. Lastly, it discusses the necessary precautions and challenges that will need to be overcome before the chemopreventive power of dietary-based intervention strategies can be fully harnessed.

The role of short-chain fatty acids in microbiota-gut-brain communication

Short-chain fatty acids (SCFAs), the main metabolites produced by bacterial fermentation of dietary fibre in the gastrointestinal tract, are speculated to have a key role in microbiota-gut-brain crosstalk. However, the pathways through which SCFAs might influence psychological functioning, including affective and cognitive processes and their neural basis, have not been fully elucidated. Furthermore, research directly exploring the role of SCFAs as potential mediators of the effects of microbiota-targeted interventions on affective and cognitive functioning is sparse, especially in humans. This Review summarizes existing knowledge on the potential of SCFAs to directly or indirectly mediate microbiota-gut-brain interactions. The effects of SCFAs on cellular systems and their interaction with gut-brain signalling pathways including immune, endocrine, neural and humoral routes are described. The effects of microbiota-targeted interventions such as prebiotics, probiotics and diet on psychological functioning and the putative mediating role of SCFA signalling will also be discussed, as well as the relationship between SCFAs and psychobiological processes. Finally, future directions to facilitate direct investigation of the effect of SCFAs on psychological functioning are outlined.

Effects of Intestinal Microbial⁻Elaborated Butyrate on Oncogenic Signaling Pathways

The intestinal microbiota is well known to have multiple benefits on human health, including cancer prevention and treatment. The effects are partially mediated by microbiota-produced short chain fatty acids (SCFAs) such as butyrate, propionate and acetate. The anti-cancer effect of butyrate has been demonstrated in cancer cell cultures and animal models of cancer. Butyrate, as a signaling molecule, has effects on multiple signaling pathways. The most studied effect is its inhibition on histone deacetylase (HDAC), which leads to alterations of several important oncogenic signaling pathways such as JAK2/STAT3, VEGF. Butyrate can interfere with both mitochondrial apoptotic and extrinsic apoptotic pathways. In addition, butyrate also reduces gut inflammation by promoting T-regulatory cell differentiation with decreased activities of the NF-κB and STAT3 pathways. Through PKC and Wnt pathways, butyrate increases cancer cell differentiation. Furthermore, butyrate regulates oncogenic signaling molecules through microRNAs and methylation. Therefore, butyrate has the potential to be incorporated into cancer prevention and treatment regimens. In this review we summarize recent progress in butyrate research and discuss the future development of butyrate as an anti-cancer agent with emphasis on its effects on oncogenic signaling pathways. The low bioavailability of butyrate is a problem, which precludes clinical application. The disadvantage of butyrate for medicinal applications may be overcome by several approaches including nano-delivery, analogue development and combination use with other anti-cancer agents or phytochemicals.

Dietary fiber sources and human benefits: The case study of cereal and pseudocereals

Dietary fiber (DF) includes the remnants of the edible part of plants and analogous carbohydrates that are resistant to digestion and absorption in the human small intestine with complete or partial fermentation in the human large intestine. DF can be classified into two main groups according to its solubility, namely insoluble dietary fiber (IDF) that mainly consists on cell wall components, including cellulose, some hemicelluloses, lignin and resistant starch, and soluble dietary fiber (SDF) that consists of non-cellulosic polysaccharides as non-digestible oligosaccharides, arabinoxylans (AX), β-glucans, some hemicelluloses, pectins, gums, mucilages and inulin. The intake of DF is associated with health benefits. IDF can contribute to the normal function of the intestinal tract and it has an important role in the prevention of colonic diverticulosis and constipation. SDF is extensively fermented by gut microbiota and it is associated with carbohydrate and lipid metabolism, with important health benefits due to its hypocholesterolemic properties. Due to these nutritional and health properties, DF is widely used as functional ingredients in food industry, being whole grain cereals, pulses, fruits and vegetables the main sources of DF. Also some synthetic sources are employed, namely polydextrose, hydroxypropyl methylcellulose or cyclodextrins. The DF content of cereals varies depending on cultivars, their botanical components (pericarp, emdosperm and germ) and the processing conditions they have undergone (baking, extrusion, etc.). In cereal grains, AX are the predominant non-cellulose DF polysaccharides followed by cellulose and β-glucans, while in pseudocereals, pectins are quantitatively predominant.

Tributyrin in Inflammation: Does White Adipose Tissue Affect Colorectal Cancer?

Colorectal cancer affects the large intestine, leading to loss of white adipose tissue (WAT) and alterations in adipokine secretion. Lower incidence of colorectal cancer is associated with increased fibre intake. Fructooligosaccharides (FOS) are fibres that increase production of butyrate by the intestinal microbiota. Tributyrin, a prodrug of butyric acid, exerts beneficial anti-inflammatory effects on colorectal cancer. Our aim was to characterise the effects of diets rich in FOS and tributyrin within the context of a colon carcinogenesis model, and characterise possible support of tumorigenesis by WAT. C57/BL6 male mice were divided into four groups: a control group (CT) fed with chow diet and three colon carcinogenesis-induced groups fed either with chow diet (CA), tributyrin-supplemented diet (BUT), or with FOS-supplemented diet. Colon carcinogenesis decreased adipose mass in subcutaneous, epididymal, and retroperitoneal tissues, while also reducing serum glucose and leptin concentrations. However, it did not alter the concentrations of adiponectin, interleukin (IL)-6, IL-10, and tumour necrosis factor alpha (TNF)-α in WAT. Additionally, the supplements did not revert the colon cancer affected parameters. The BUT group exhibited even higher glucose tolerance and levels of IL-6, VEGF, and TNF-α in WAT. To conclude our study, FOS and butyrate supplements were not beneficial. In addition, butyrate worsened adipose tissue inflammation.

Differences in risk factor-colorectal adenoma associations according to non-steroidal anti-inflammatory drug use

OBJECTIVE

Because multiple observational studies and large, randomized controlled trials indicate that NSAIDs strongly reduce the risk of colorectal neoplasms, we investigated whether NSAID use masks associations of various other risk factors with colorectal neoplasms.

MATERIALS AND METHODS

Using pooled data from three case-control studies of incident, sporadic colorectal adenoma (pooled n=789 cases, 2035 polyp-free controls), using multivariable logistic regression, we investigated various risk factor-colorectal adenoma associations stratified by NSAID use.

RESULTS

Example multivariable-adjusted odds ratios [95% confidence intervals (CI)] for those in the highest relative to the lowest quartiles of exposure, by regular nonaspirin NSAID nonuse/use, respectively, were 1.57 (95% CI: 0.96-2.55) versus 1.14 (95% CI: 0.37, 3.49) for total fat, 1.37 (95% CI: 0.86-2.18) versus 0.70 (95% CI: 0.23-2.25) for saturated fat, 0.93 (95% CI: 0.68-1.28) versus 1.30 (95% CI: 0.61-2.75) for calcium, 0.89 (95% CI: 0.64-1.23) versus 1.38 (95% CI: 0.65-2.94) for total fruits and vegetables, and 0.85 (95% CI: 0.65-1.11) versus 0.94 (95% CI: 0.52-1.71) for physical activity. For current versus never smokers, the odds ratios (95% CIs) among regular non-NSAID users/nonusers were 2.91 (95% CI: 2.22-3.82) versus 1.75 (95% CI: 0.90-3.41), respectively, and for those who were obese versus those who were normal weight, they were 1.67 (95% CI: 1.28-2.17) versus 1.19 (95% CI: 0.69-2.04), respectively.

CONCLUSION

Our findings suggest that regular nonaspirin NSAID use may mask, beyond simple confounding, associations of major risk factors with colorectal adenoma, and support routinely assessing such associations stratified by regular nonaspirin NSAID use.