Antibiotic Use Associated With Risk of Colorectal Polyps in a Nationwide Study

The role of gut microbiota and drug interactions in the development of colorectal cancer

The human gut microbiota is a complex ecosystem regulating the host's environmental interaction. The same functional food or drug may have varying bioavailability and distinct effects on different individuals. Drugs such as antibiotics can alter the intestinal flora, thus affecting health. However, the relationship between intestinal flora and non-antibiotic drugs is bidirectional: it is not only affected by drugs; nevertheless, it can alter the drug structure through enzymes and change the bioavailability, biological activity, or toxicity of drugs to improve their efficacy and safety. This review summarizes the roles and mechanisms of antibiotics, antihypertensive drugs, nonsteroidal anti-inflammatory drugs, lipid-lowering drugs, hypoglycemic drugs, virus-associated therapies, metabolites, and dietary in modulating the colorectal cancer gut microbiota. It provides a reference for future antitumor therapy targeting intestinal microorganisms.

Changes in the Gut Microbiome Associated with Intussusception in Patients with Peutz-Jeghers Syndrome

Peutz-Jeghers syndrome (PJS) is a rare hereditary disorder characterized by intestinal polyposis, and intestinal intussusception is one of the most urgent complications. While it is known that imbalance of the gut microbiota is highly associated with intestinal disorders, the role of the gut microbiome in the pathogenesis of PJS has not been reported. In this study, we performed 16S rRNA sequencing on stools from 168 patients and 68 healthy family members who lived together to determine the gut microbiome composition of PJS patients. Metagenomics sequencing was further performed on the representative samples (61 PJS patients and 27 healthy family members) to analyze the functional changes. We found that the fecal microbiome of patients with PJS showed a greater variation in β-diversity. An enhancement of Escherichia coli and a reduction of Faecalibacterium prausnitzii was identified in PJS patients. Further reduction of Faecalibacterium prausnitzii was the characteristic microbial change observed in patients with intussusception. Functional analysis revealed that the abundance of propanoate metabolism was enriched in PJS patients and further enriched in those with intussusception. Escherichia coli was the major contributor to the enrichment of this metabolism pathway, which was associated with the abnormal expression of methylglyoxal synthase (encoded by mgsA) and phosphate acetyltransferase (encoded by pta). Our findings showed a distinct gut microbiome signature in PJS patients and identified the connection between the gut microbiome and intussusception. Alterations in the gut microbiome might be involved in the pathogenesis of PJS and may serve as biomarkers for gastrointestinal surveillance. IMPORTANCE Recent research has established a link between the gut microbiome and polyps and neoplasia, and antibiotic use influences the microbiome and the development of colorectal polyps. Familial adenomatous polyposis (FAP), which is characterized by the early development of benign precursor lesions (polyps), is associated with enterotoxigenic Bacteroides fragilis and Escherichia coli biofilms. However, the relationship between the gut microbiome and the pathophysiology of PJS has not yet been established. In this study, we found that PJS patients had a distinct microbiome composition, with a greater variation in β-diversity, an increase in Escherichia coli, and a decrease in Faecalibacterium prausnitzii. A further reduction of Faecalibacterium prausnitzii was observed in patients with intussusception. Moreover, PJS involved increased propanoate metabolism as well as abnormal mgsA and pta expression. These findings may contribute to a better understanding of the etiology of PJS and improve disease control strategies.

Gut microbiota signatures in tissues of the colorectal polyp and normal colorectal mucosa, and faeces

Background

Colorectal polyps are the most common precursors of colorectal cancer (CRC). The close relationship has been observed between colorectal polyps and gut microbiota. However, gut microbiota signatures among sampling sites in patients with colorectal polyps and healthy adults remain elusive.

Aims

To learn about gut microbiota signatures in tissues of the colorectal polyp and normal colorectal mucosa, and faeces.

Methods

We performed 16S rRNA gene sequencing and bioinformatic analysis for the microbiota in the normal colorectal mucosa, the colorectal polyps and faeces of adults with colorectal polyps (n = 24) and in faeces and normal mucosa of healthy adults (n = 16) in this preliminary trial.

Results

The Ace and Chao indexes were higher in the normal colorectal mucosa and polyp tissues compared to faecal samples (P < 0.05). The composition of microbiota based on PCoA and ANOSIM analysis showed the significant differences only between faeces and tissues of the normal mucosa and polyp (P < 0.05). Based on the LEfSe analysis, the abundances of Bacteroides, Prevotella-2 and Agathobacter were higher, whereas the abundances of Haemophilus, Escherichia_Shigella, Fusobacterium and Streptococcus were lower in faeces both in patients with colorectal polyp and healthy individuals, compared with those in the normal mucosa in two groups or polyp tissues. In healthy individuals, the abundance of Fusobacterium was significantly higher in the normal colorectal mucosa than in faeces. Moreover, there was no significant difference in the abundance of Fusobacterium between the normal colorectal mucosa and polyps in patients with colorectal polyps, but it was significantly higher in the mucosa and polyps than in faeces. Remarkably, the abundance of Fusobacterium in the normal colorectal mucosa was significantly higher in healthy individuals than in the polyp group.

Conclusions

The microbial structure in faeces differs from that in tissues of polyp and normal mucusa. Additionally, Fusobacterium may be a normal colonizer in colonic mucosa, and an abnormal increase of Fusobacterium detected in faeces may be related with the injury of the colorectal mucosa. The difference of the faecal microbiota and mucosal microbiota should be carefully considered in studies on gut microbiota in patients with colorectal lesions.

Antibiotics use and risk of colorectal neoplasia: An updated meta-analysis

PURPOSE

Accumulating evidence indicate that antibiotic use could induce microbiome dysbiosis, which was a critical driver to the onset and progression of colorectal cancer (CRC). But the relationship between antibiotics use and CRC was still disputed. Hence, we conducted this systematic review and meta-analysis to appraise and synthesize the present available evidence to clarify the association.

METHODS

PubMed, Embase, Web of Science, and Cochrane Library were systematically searched for relevant observational studies from inception to June 5, 2020. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to explore the association between antibiotics use and CRC using random-effects model. Subgroup analyses, sensitive analyses, and publication bias were conducted to assess the robust reliability of pooled results.

RESULTS

A total of 15 observational studies containing 5,164,138 patients were included in this meta-analysis. The pooled analysis indicated that the total antibiotic use was correlated with increased risk of CRC (OR, 1.11; 95% CI, 1.05-1.18). The subgroup analyses suggested that antibiotic use significantly elevated risk of colon cancer, but not rectal cancer. Furthermore, we found that penicillin, cephalosporin, anti-anaerobic, and anti-aerobic antibiotics increased the risk of CRC, in particular metronidazole but no significant associations were identified in macrolide, tetracycline, sulfonamides, nitrofurans, and quinolone use. The results of sensitive analyses and publication bias indicated the conclusions were robust.

CONCLUSION

The findings showed that antibiotics use may be associated with the onset of CRC. Policy-makers and clinicians should adequately assess possible benefits and harms of antibiotics use, especially in some high-risk populations. Also, for high-risk patients with previous antibiotics use, it was suggested to perform early colonoscopy screening to find or even eliminate early-stage CRC.

Is early-onset cancer an emerging global epidemic? Current evidence and future implications

Over the past several decades, the incidence of early-onset cancers, often defined as cancers diagnosed in adults <50 years of age, in the breast, colorectum, endometrium, oesophagus, extrahepatic bile duct, gallbladder, head and neck, kidney, liver, bone marrow, pancreas, prostate, stomach and thyroid has increased in multiple countries. Increased use of screening programmes has contributed to this phenomenon to a certain extent, although a genuine increase in the incidence of early-onset forms of several cancer types also seems to have emerged. Evidence suggests an aetiological role of risk factor exposures in early life and young adulthood. Since the mid-20th century, substantial multigenerational changes in the exposome have occurred (including changes in diet, lifestyle, obesity, environment and the microbiome, all of which might interact with genomic and/or genetic susceptibilities). However, the effects of individual exposures remain largely unknown. To study early-life exposures and their implications for multiple cancer types will require prospective cohort studies with dedicated biobanking and data collection technologies. Raising awareness among both the public and health-care professionals will also be critical. In this Review, we describe changes in the incidence of early-onset cancers globally and suggest measures that are likely to reduce the burden of cancers and other chronic non-communicable diseases.

Antibiotic Therapy and Risk of Early-Onset Colorectal Cancer: A National Case-Control Study

INTRODUCTION

Antibiotic use has emerged as a risk factor for colorectal neoplasia and is hypothesized as a contributor to the rising incidence of colorectal cancer under age 50 years or early-onset colorectal cancer (EOCRC). However, the impact of antibiotic use and risk of EOCRC is unknown.

METHODS

We conducted a population-based case-control study of CRC among individuals aged ≥18 years in the Epidemiology Strengthened by histoPathology Reports in Sweden (ESPRESSO) cohort (2006-2016). The primary outcome was EOCRC. A secondary outcome was CRC at any age. Incident CRC was pathologically confirmed, and for each, up to 5 population-based controls were matched on age, sex, county of residence, and calendar year. We assessed prescriptions until 6 months before CRC diagnosis. Conditional logistic regression was used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

RESULTS

We identified 54,804 cases of CRC (2,557 EOCRCs) and 261,089 controls. Compared with none, previous antibiotic use was not associated with EOCRC risk after adjustment for potential confounders (aOR 1.06, 95% CI: 0.96, 1.17) with similarly null findings when stratified by anatomic tumor site. In contrast, previous antibiotic use was weakly associated with elevated risk for CRC at any age (aOR 1.05, 95% CI: 1.02, 1.07). A potential but modest link between broad-spectrum antibiotic use and EOCRC was observed (aOR 1.13, 95% CI: 1.02, 1.26).

DISCUSSION

We found no conclusive evidence that antibiotics are associated with EOCRC risk. Although antibiotic use was weakly associated with risk of CRC at any age, the magnitude of association was modest, and the study period was relatively short.

Two Antibiotics, Ampicillin and Tetracycline, Exert Different Effects in HT-29 Colorectal Adenocarcinoma Cells in Terms of Cell Viability and Migration Capacity

Antibiotics are considered the cornerstone of modern medicine; however, currently, antibiotic resistance has become a global health issue. Antibiotics also find new uses in the treatment of other pathologies as well as cancer. The present study aimed to verify the impact of tetracycline and ampicillin in a colorectal adenocarcinoma cell line, HT-29. The effects of the two antibiotics on cell viability and nucleus were evaluated by the means of MTT assay and the Hoechst staining method, respectively. The irritant potential at vascular level of the chorioallantoic membrane was tested by the HET-CAM assay. Treatment of HT-29 cells with the two antibiotics determined different effects: (i) tetracycline induced a dose- and time-dependent cytotoxic effect characterized by decreased cell viability, changes in cells morphology, apoptotic features (nuclear fragmentation), and inhibition of cellular migration, whereas (ii) ampicillin exerted a biphasic response-cytotoxic at low doses and proliferative at high concentrations. In terms of effect on blood vessels, both antibiotics exerted a mild irritant effect. These results are promising and could be considered as starting point for further in vitro studies to define the molecular mechanisms involved in the cytotoxic/proliferative effects.

Antibiotic Consumption Patterns in European Countries May Be Associated with the Incidence of Major Carcinomas

The possible role of the altered intestinal microbiome in the development of malignancies has been raised recently in several publications. Among external factors, antibiotics are considered to be the most important agent capable of producing dysbiosis in the gut flora, either temporally or permanently. The human microbiome has several beneficial effects in terms of maintaining appropriate human health, but its alteration has been implicated in the development of many illnesses. Our basic aim was to explore a possible relationship between the consumption of different antibiotic classes and the incidence of the most common cancer types (male, female) in European countries. A database of the average, yearly antibiotic consumption (1997–2018) has been developed and the consumption figures were compared to the eight, most frequent cancer incidence calculated for 2018 in 30 European countries. Pearson correlation has indicated different degrees of positive (supportive) and negative (inhibitor) significant associations between antibiotic consumption figures and cancer prevalence. It has been observed that certain antibiotic classes with positive correlation probably augment the incidence of certain cancer types, while others, with negative correlation, may show some inhibitory effect. The relatively higher or lower consumption pattern of different classes of antibiotics could be related to certain cancer prevalence figures in different European countries. Our results indicated that countries with relatively high consumption of narrow-spectrum penicillin (J01CE, J01CF) and tetracycline (J01A), like certain Scandinavian countries, showed a higher incidence of female colorectal cancer, female lung cancer, melanoma, breast, prostate and uterus corpus cancer. Countries with relatively higher consumption of broad-spectrum penicillin (J01CA, J01CR) and some broad-spectrum antibiotics (J01D, J01F, J01M), like Greece, Hungary, Slovakia, France, etc. showed a higher incidence rate of male lung cancer and male bladder cancer. The higher incidence rate of different cancer types showed association with the higher consumption of antibiotics with “augmenting” properties and with less consumption of antibiotics with “inhibitory” properties.