Role of diet and gut microbiota on colorectal cancer immunomodulation

Colorectal cancer(CRC) is one of the most commonly diagnosed cancers, and it is characterized by genetic and epigenetic alterations, as well as by inflammatory cell infiltration among malignant and stromal cells. However, this dynamic infiltration can be influenced by the microenvironment to promote tumor proliferation, survival and metastasis or cancer inhibition. In particular, the cancer microenvironment metabolites can regulate the inflammatory cells to induce a chronic inflammatory response that can be a predisposing condition for CRC retention. In addition, some nutritional components might contribute to a chronic inflammatory condition by regulating various immune and inflammatory pathways. Besides that, diet strongly modulates the gut microbiota composition,which has a key role in maintaining gut homeostasis and is associated with the modulation of host inflammatory and immune responses. Therefore, diet has a fundamental role in CRC initiation, progression and prevention. In particular,functional foods such as probiotics, prebiotics and symbiotics can have a potentially positive effect on health beyond basic nutrition and have antiinflammatory effects. In this review, we discuss the influence of diet on gut microbiota composition, focusing on its role on gut inflammation and immunity.Finally, we describe the potential benefits of using probiotics and prebiotics to modulate the host inflammatory response, as well as its application in CRC prevention and treatment.

Evaluation and comparison of short chain fatty acids composition in gut diseases

BACKGROUND An altered (dysbiosis) and unhealthy status of the gut microbiota is usually responsible for a reduction of short chain fatty acids (SCFAs) concentration. SCFAs obtained from the carbohydrate fermentation processes are crucial in maintaining gut homeostasis and their determination in stool samples could provide a faster, reliable and cheaper method to highlight the presence of an intestinal dysbiosis and a biomarker for various gut diseases. We hypothesize that different intestinal diseases, such as celiac disease (CD), adenomatous polyposis (AP) and colorectal cancer (CRC) could display a particular fecal SCFAs’ signature. AIM To compare the fecal SCFAs’ profiles of CD, AP, CRC patients and healthy controls, using the same analytical method. METHODS In this cross-sectional study, we defined and compared the SCFAs’ concentration in fecal samples of 9 AP, 16 CD, 19 CRC patients and 16 healthy controls (HC). The SCFAs’ analysis were performed using a gas-chromatography coupled with mass spectrometry method. Data analysis was carried out using Wilcoxon ranksum test to assess pairwise differences of SCFAs’ profiles, partial least squaresdiscriminate analysis (PLS-DA) to determine the status membership based on distinct SCFAs’ profiles, and Dirichlet regression to determine factors influencing concentration levels of SCFAs. RESULTS We have not observed any difference in the SCFAs’ amount and composition between CD and healthy control. On the contrary, the total amount of SCFAs was significantly lower in CRC patients compared to HC (P = 0.044) and CD (P = 0.005). Moreover, the SCFAs’ percentage composition was different in CRC and AP compared to HC. In detail, HC displayed higher percentage of acetic acid (P value = 1.3 × 10-6) and a lower amount of butyric (P value = 0.02192), isobutyric (P value = 7.4 × 10-5), isovaleric (P value = 0.00012) and valeric (P value = 0.00014) acids compared to CRC patients. AP showed a lower abundance of acetic acid (P value = 0.00062) and higher percentages of propionic (P value = 0.00433) and isovaleric (P value = 0.00433) acids compared to HC. Moreover, AP showed higher levels of propionic acid (P value = 0.03251) and a lower level of isobutyric acid (P value = 0.00427) in comparison to CRC. The PLS-DA model demonstrated a significant separation of CRC and AP groups from HC, although some degree of overlap was observed between CRC and AP. CONCLUSION Analysis of fecal SCFAs shows the potential to provide a non-invasive means of diagnosis to detect patients with CRC and AP, while CD patients cannot be discriminated from healthy subjects.

Immunomodulation by probiotics and prebiotics in hepatocellular carcinoma

Hepatocellular carcinoma(HCC)is the most prevalent primary malignancy in patients suffering from chronic liver diseases and cirrhosis.Recent attention has been paid to the involvement of the gut-liver axis(GLA)in HCC pathogenesis.This axis results from a bidirectional,anatomical and functional relationship between the gastrointestinal system and the liver.Moreover,the complex network of interactions between the intestinal microbiome and the liver plays a crucial role in modulation of the HCC-tumor microenvironment,contributing to the pathogenesis of HCC by exposing the liver to pathogen-associated molecular patterns,such as bacterial lipopolysaccharides,DNA,peptidoglycans and flagellin.Indeed,the alteration of gut microflora may disturb the intestinal barrier,bringing several toll-like receptor ligands to the liver thus activating the inflammatory response.This review explores the new therapeutic opportunities that may arise from novel insights into the mechanisms by which microbiota immunomodulation,represented by probiotics,and prebiotics,affects HCC through the GLA.

Effect of ancient Khorasan wheat on gut microbiota,inflammation,and short-chain fatty acid production in patients with fibromyalgia

BACKGROUND Fibromyalgia(FM)syndrome is mainly characterized by widespread pain,sleeping disorders,fatigue,and cognitive dysfunction.In many cases,gastrointestinal distress is also reported,suggesting the potential pathogenic role of the gut microbiota(GM).The GM is deeply influenced by several environmental factors,especially the diet,and recent findings highlighted significant symptom improvement in FM patients following various nutritional interventions such as vegetarian diet,low-fermentable oligosaccharides,disaccharides,monosaccharides,and polyols based diets,gluten-free diet,and especially an ancient grain supplementation.In particular,a recent study reported that a replacement diet with ancient Khorasan wheat led to an overall improvement in symptom severity of FM patients.AIM To examine the effects of ancient Khorasan wheat on the GM,inflammation,and short-chain fatty acid production in FM patients.METHODS After a 2-wk run-in period,20 FM patients were enrolled in this randomized,double-blind crossover trial.In detail,they were assigned to consume either Khorasan or control wheat products for 8 wk and then,following an 8-wk washout period,crossed.Before and after treatments,GM characterization was performed by 16S rRNA sequencing while the fecal molecular inflammatory response and the short-chain fatty acids(SCFAs)were respectively determined with the Luminex MAGPIX detection system and a mass chromatography-mass spectrometry method.RESULTS The Khorasan wheat replacement diet,in comparison with the control wheat diet,had more positive effects on intestinal microbiota composition and on both the fecal immune and SCFAs profiles such as the significant increase of butyric acid levels(P=0.054),candidatus Saccharibacteria(P=9.95e-06)and Actinobacteria,and the reduction of Enterococcaceae(P=4.97e-04).Moreover,the improvement of various FM symptoms along with the variation of some gut bacteria after the Khorasan wheat diet have been documented;in fact we reported positive correlations between Actinobacteria and both Tiredness Symptoms Scale(P<0.001)and Functional Outcome of Sleep Questionnaire(P<0.05)scores,between Verrucomicrobiae and both Widespread Pain Index(WPI)+Symptom Severity scale(SS)(P<0.05)and WPI(P<0.05)scores,between candidatus Saccharibacteria and SS score(P<0.05),and between Bacteroidales and Sleep-Related and Safety Behaviour Questionnaire score(P<0.05).CONCLUSION The replacement diet based on ancient Khorasan wheat results in beneficial GM compositional and functional modifications that positively correlate with an improvement of FM symptomatology.

Microbiota and viral hepatitis:State of the art of a complex matter

Changes in gut microbiota influence both the gut and liver,which are strictly connected by the so-called“gut-liver axis”.The gut microbiota acts as a major determinant of this relationship in the onset and clinical course of liver diseases.According to the results of several studies,gut dysbiosis is linked to viral hepatitis,mainly hepatitis C virus and hepatitis B virus infection.Gut bacteriaderived metabolites and cellular components are key molecules that affect liver function and modulate the pathology of viral hepatitis.Recent studies showed that the gut microbiota produces various molecules,such as peptidoglycans,lipopolysaccharides,DNA,lipoteichoic acid,indole-derivatives,bile acids,and trimethylamine,which are translocated to the liver and interact with liver immune cells causing pathological effects.Therefore,the existence of crosstalk between the gut microbiota and the liver and its implications on host health and pathologic status are essential factors impacting the etiology and therapeutic approach.Concrete mechanisms behind the pathogenic role of gut-derived components on the pathogenesis of viral hepatitis remain unclear and not understood.In this review,we discuss the current findings of research on the bidirectional relationship of the components of gut microbiota and the progression of liver diseases and viral hepatitis and vice versa.Moreover,this paper highlights the current therapeutic and preventive strategies,such as fecal transplantation,used to restore the gut microbiota composition and so improve host health.

Multiplex gene expression profile in inflamed mucosa of patients with Crohn’s disease ileal localization: A pilot study

BACKGROUND Crohn’s disease (CD) is a complex disorder resulting from the interaction of genetic,environmental,and microbial factors.The pathogenic process may potentially affect any segment of the gastrointestinal tract,but a selective location in the terminal ileum was reported in 50% of patients.AIM To characterize clinical sub-phenotypes (colonic and/or ileal) within the same disease,in order to identify new therapeutic targets.METHODS 14 consecutive patients undergoing surgery for ileal CD were recruited for this study.Peripheral blood samples from each patient were collected and the main polymorphisms of the gene Card15/Nod2 (R702W,G908R,and 1007fs) were analyzed in each sample.In addition,tissue samples were taken from both the tract affected by CD and from the apparently healthy and disease-free margins (internal controls).We used a multiplex gene assay in specimens obtained from patients with ileal localization of CD to evaluate the simultaneous expression of 24 genes involved in the pathogenesis of the disease.We also processed surgery gut samples with routine light microscopy (LM) and transmission electron microscopy (TEM) techniques to evaluate their structural and ultrastructural features.RESULTS We found a significant increase of Th17 (IL17A and IL17F,IL 23R and CCR6) and Th1 (IFN-γ) gene expression in inflamed mucosa compared to non-inflamed sites of 14 CD patients.DEFB4 and HAMP,two genes coding for antimicrobial peptides,were also strongly activated in inflamed ileal mucosa,suggesting the overwhelming stimulation of epithelial cells by commensal microbiota.IFN-γ and CCR6 were more expressed in inflamed mucosa of CD patients with ileal localization compared with patients with colonic localization suggesting a more aggressive inflammation process in this site.Morphological analysis of the epithelial lining of Lieberkün crypts disclosed enhanced release activity from goblet mucocytes,whereas the lamina propria contained numerous cells pertaining to various lines.CONCLUSION We observed that the expression of ileal genes related to Th1 and Th17 activity is strongly activated as well as the expression of genes involved in microbiota regulation.

Effects of viremia and CD4 recovery on gut“microbiome-immunity”axis in treatment-na?ve HIV-1-infected patients undergoing antiretroviral therapy

BACKGROUND Human immunodeficiency virus type 1(HIV-1)infection is characterized by persistent systemic inflammation and immune activation,even in patients receiving effective antiretroviral therapy(ART).Converging data from many cross-sectional studies suggest that gut microbiota(GM)changes can occur throughout including human immunodeficiency virus(HIV)infection,treated by ART;however,the results are contrasting.For the first time,we compared the fecal microbial composition,serum and fecal microbial metabolites,and serum cytokine profile of treatment-na?ve patients before starting ART and after reaching virological suppression,after 24 wk of ART therapy.In addition,we compared the microbiota composition,microbial metabolites,and cytokine profile of patients with CD4/CD8 ratio<1(immunological non-responders[INRs])and CD4/CD8>1(immunological responders[IRs]),after 24 wk of ART therapy.AIM To compare for the first time the fecal microbial composition,serum and fecal microbial metabolites,and serum cytokine profile of treatment-na?ve patients before starting ART and after reaching virological suppression(HIV RNA<50 copies/m L)after 24 wk of ART.METHODS We enrolled 12 treatment-na?ve HIV-infected patients receiving ART(mainly based on integrase inhibitors).Fecal microbiota composition was assessed through next generation sequencing.In addition,a comprehensive analysis of a blood broad-spectrum cytokine panel was performed through a multiplex approach.At the same time,serum free fatty acid(FFA)and fecal short chain fatty acid levels were obtained through gas chromatography-mass spectrometry.RESULTS We first compared microbiota signatures,FFA levels,and cytokine profile before starting ART and after reaching virological suppression.Modest alterations were observed in microbiota composition,in particular in the viral suppression condition,we detected an increase of Ruminococcus and Succinivibrio and a decrease of Intestinibacter.Moreover,in the same condition,we also observed augmented levels of serum propionic and butyric acids.Contemporarily,a reduction of serum IP-10 and an increase of IL-8 levels were detected in the viral suppression condition.In addition,the same components were compared between IRs and INRs.Concerning the microflora population,we detected a reduction of Faecalibacterium and an increase of Alistipes in INRs.Simultaneously,fecal isobutyric,isovaleric,and 2-methylbutyric acids were also increased in INRs.CONCLUSION Our results provided an additional perspective about the impact of HIV infection,ART,and immune recovery on the"microbiome-immunity axis"at the metabolism level.These factors can act as indicators of the active processes occurring in the gastrointestinal tract.Individuals with HIV-1 infection,before ART and after reaching virological suppression with 24 wk of ART,displayed a microbiota with unchanged overall bacterial diversity;moreover,their systemic inflammatory status seems not to be completely restored.In addition,we confirmed the role of the GM metabolites in immune reconstitution.

Exploring the food-gut axis in immunotherapy response of cancer patients

Nowadays,immunotherapy is widely used to treat different cancer types as it boosts the body's natural defenses against the malignancy,with lower risk of adverse events compared to the traditional treatments.The immune system is able to control cancer growth but,unfortunately,many cancers take advantage of immune checkpoints pathways for the immune evasion.An intricate network of factors including tumor,host and environmental variables influence the individual response to immune checkpoints’inhibitors.Between them,the gut microbiota(GM)has recently gained increasing attention because of its emerging role as a modulator of the immune response.Several studies analyzed the diversities between immunotherapy-sensitive and immunotherapy-resistant cohorts,evidencing that particular GM profiles were closely associated to treatment effect.In addition,other data documented that interventional GM modulation could effectively enhance efficacy and relieve resistance during immunotherapy treatment.Diet represents one of the major GM determinants,and ongoing studies are examining the role of the food-gut axis in immunotherapy treatment.Here,we review recent studies that described how variations of the GM affects patient’s responsivity to anti-cancer immunotherapy and how diet-related factors impact on the GM modulation in cancer,outlining potential future clinical directions of these recent findings.

Fecal metabolomic profiles: A comparative study of patients with colorectal cancer vs adenomatous polyps

BACKGROUND Colorectal cancer(CRC),the third most common cause of death in both males and females worldwide,shows a positive response to therapy and usually a better prognosis when detected at an early stage.However,the survival rate declines when the diagnosis is late and the tumor spreads to other organs.Currently,the measures widely used in the clinic are fecal occult blood test and evaluation of serum tumor markers,but the lack of sensitivity and specificity of these markers restricts their use for CRC diagnosis.Due to its high sensitivity and precision,colonoscopy is currently the gold-standard screening technique for CRC,but it is a costly and invasive procedure.Therefore,the implementation of custom-made methodologies including those with minimal invasiveness,protection,and reproducibility is highly desirable.With regard to other screening methods,the screening of fecal samples has several benefits,and metabolomics is a successful method to classify the metabolite shift in living systems as a reaction to pathophysiological influences,genetic modifications,and environmental factors.AIM To characterize the variation groups and potentially recognize some diagnostic markers,we compared with healthy controls(HCs)the fecal nuclear magnetic resonance(NMR)metabolomic profiles of patients with CRC or adenomatous polyposis(AP).METHODS Proton nuclear magnetic resonance spectroscopy was used in combination with multivariate and univariate statistical approaches,to define the fecal metabolic profiles of 32 CRC patients,16 AP patients,and 38 HCs well matched in age,sex,and body mass index.RESULTS NMR metabolomic analyses revealed that fecal sample profiles differed among CRC patients,AP patients,and HCs,and some discriminatory metabolites including acetate,butyrate,propionate,3-hydroxyphenylacetic acid,valine,tyrosine and leucine were identified.CONCLUSION In conclusion,we are confident that our data can be a forerunner for future studies on CRC management,especially the diagnosis and evaluation of the effectiveness of treatments.