Gut microbiome is more stable in males than in females during the development of colorectal cancer

Microbiota-based therapies as novel targets for autism spectrum disorder: A systematic review and meta-analysis

BACKGROUND

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition characterized by persistent deficits in social interaction and communication. Emerging evidence suggests that alterations in the gut-brain axis play a key role in the pathophysiology of ASD, and that microbiota-targeted interventions may offer therapeutic benefits. However, no clear consensus has been reached regarding the effectiveness of these strategies in ameliorating behavioral characteristics. This systematic review and meta-analysis (PROSPERO registration ID: CRD42023494067) aimed to evaluate the impact of microbiota-based interventions-including synbiotics, prebiotics, single-strain probiotics, probiotic blends, and fecal microbiota transplantation (FMT)-on behavioral outcomes in individuals with ASD, with particular emphasis on social functioning.

RESULTS

Of the 373 records initially identified, 20 studies met the inclusion criteria, comprising 16 randomized controlled trials and 4 open-label studies. The overall effect size indicated a statistically significant improvement in ASD-related behavioral symptoms following microbiota manipulation (Hedges' g = 0.47; 95 % CI: 0.30-0.64; p < 0.001; I2 = 33.01 %), representing a small but clinically relevant effect. Heterogeneity was classified as moderate. Among the interventions, FMT and probiotic blends yielded the most substantial effects. All major limitations of the current studies were thoroughly addressed and discussed to guide future experimental designs. Additionally, we examined preclinical evidence supporting the involvement of neural, immune, and metabolic pathways in mediating the observed behavioral improvements.

CONCLUSIONS

Our findings support the potential of microbiota-based therapies as a promising and well-tolerated strategy for improving behavioral symptoms in individuals with ASD. FMT and multi-strain probiotic formulations appear particularly effective. Nevertheless, further high-quality randomized controlled trials-especially involving FMT-are urgently needed to validate these results and guide clinical implementation. Thus, these findings provide a critical foundation for future investigations seeking to refine microbiota-based interventions and uncover the underlying mechanisms through which they influence ASD-related behaviors.

The Effect of Gender on the Intestinal Flora of Colorectal Cancer Under Different Stages

This study aims to determine whether gender is a factor in the interplay between the human intestinal flora and colorectal cancer (CRC), ultimately providing new evidence for the clinical prediction and management of CRC in different genders. In this study, we included 186 untreated CRC patients, and classified them into two groups based on pathological staging: Groups Ⅰ-Ⅱ and Groups Ⅲ-Ⅳ, with male and female groups within each group. We collected preoperative fecal samples from these patients and performed 16S rRNA gene sequencing to analyze their intestinal flora. In the CRC Stages I-II cohort, the gut microbiota of the female group exhibited greater diversity and abundance compared to the male group, with a total of 13 gut microbiota demonstrating significant disparities. Notably, s__Parabacteroides gordonii, s__Bacteroides faecis, and s__Bacteroides nordii were found to be more prevalent in the female group relative to the male group. Within the CRC Stages III-IV cohort, 51 gut microbiota exhibited significant differences between the genders. In the immunocyte composition of fecal samples from patients with CRC, a higher proportion of naive B cells is observed in the male group as compared to the female group. In female CRC patients within the CRC Stages III-IV cohort, Actinomyces exhibited a significant negative correlation with activated dendritic cells, CD4+ memory T cells, and eosinophils. In male CRC patients within the CRC Stages III-IV cohort, Actinomyces demonstrated a significant positive correlation with naive B cells and a significant positive correlation with immune activation genes TNFRSF25 and TMIGD2. In female CRC patients within the CRC Stages III-IV cohort, Actinomyces showed a significant negative correlation with activated dendritic cells, CD4+ memory T cells, and eosinophils, and a significant positive correlation with immune activation genes TNFSF13B, LTA, KLRK1, and CXCL12. In the CRC Stages I-II group, the female group's intestinal flora is more diverse and richer than the male group. In the CRC Stages III-IV group, there are a total of 51 different intestinal flora in both the male and female groups. We also found that Actinomyces affects the occurrence and development of CRC in the male and female groups through different pathways. The results show that the intestinal flora differs between male and female CRC patients and is closely associated with cancer development.

Should we consider microbiota-based interventions as a novel therapeutic strategy for schizophrenia? A systematic review and meta-analysis

Schizophrenia is a chronic psychiatric disorder characterized by a variety of symptoms broadly categorized into positive, negative, and cognitive domains. Its etiology is multifactorial, involving a complex interplay of genetic, neurobiological, and environmental factors, and its neurobiology is associated with abnormalities in different neurotransmitter systems. Due to this multifactorial etiology and neurobiology, leading to a wide heterogeneity of symptoms and clinical presentations, current antipsychotic treatments face challenges, underscoring the need for novel therapeutic approaches. Recent studies have revealed differences in the gut microbiome of individuals with schizophrenia compared to healthy controls, establishing an intricate link between this disorder and gastrointestinal health, and suggesting that microbiota-targeted interventions could help alleviate clinical symptoms. Therefore, this meta-analysis investigates whether gut microbiota manipulation can ameliorate psychotic outcomes in patients with schizophrenia receiving pharmacological treatment. Nine studies (n = 417 participants) were selected from 81 records, comprising seven randomized controlled trials and two open-label studies, all with a low risk of bias, included in this systematic review and meta-analysis. The overall combined effect size indicated significant symptom improvement following microbiota treatment (Hedges' g = 0.48, 95% CI = 0.09 to 0.88, p = 0.004, I2 = 62.35%). However, according to Hedges' g criteria, the effect size was small (approaching moderate), and study heterogeneity was moderate based on I2 criteria. This review also discusses clinical and preclinical studies to elucidate the neural, immune, and metabolic pathways by which microbiota manipulation, particularly with Lactobacillus and Bifidobacterium genera, may exert beneficial effects on schizophrenia symptoms via the gut-brain axis. Finally, we address the main confounding factors identified in our systematic review, highlight key limitations, and offer recommendations to guide future high-quality trials with larger participant cohorts to explore microbiome-based therapies as a primary or adjunctive treatment for schizophrenia.

Gender and sex differences in colorectal cancer screening, diagnosis and treatment

Males have a higher incidence and mortality rate from colorectal cancer (CRC) compared with females. This review examines the reasons for these differences, including risk factors, screening participation, interpretation of screening tests, presentation and tumour types, pathophysiology (particularly the impact of sex hormones on tumour-related gene expression, microsatellite instability, micro-RNA expression, and the tumour microenvironment), and the efficacy and toxicity of treatment. Sex differences in hormones and body composition are responsible for some of the sexual dimorphism in CRC incidence and outcomes, particularly the pathophysiology, CRC presentation, the pharmacokinetics of cytotoxic therapies, and the impact of treatment on outcomes. However, gender differences also play a role, affecting risk factors, access to or participation in screening and treatment, and patients' experience of treatment (e.g. adverse events and sequelae). Sex and gender issues warrant further investigation in CRC to optimise treatment outcomes for patients.

Changes in Intestinal Microbiota and Their Relationship With Patient Characteristics in Colorectal Cancer

BACKGROUND

Gut microbiota are associated with the pathological features and development of colorectal cancer (CRC); however, how gut microbiota changes in patients with CRC is unknown. This study investigated the role of gut microbiota in the development and progression of CRC by retrospectively comparing the structural differences between the gut microbiota of patients with CRC and healthy individuals.

METHODS

Together with clinical data, we collected fecal samples from patients with CRC (n = 18) and healthy controls (n = 18) and performed 16S rRNA gene sequencing and alpha and beta diversity analysis to compare microbiota richness and diversity. Based on the differences in microbiota between the CRC and control groups, we identified disease-specific microbial communities after relevant factors. PICRUSt2 software was used to predict the differential microbial functions.

RESULTS

The CRC and control groups differed in both composition and abundance of intestinal microbiota. Firmicutes and Bacteroidetes were the most abundant phyla in both groups, while Verrucomicrobi was significantly more abundant in the CRC group. Megamonas, Lachnospira, and Romboutsia were more abundant in the control group; 18 genera differed significantly in abundance between the groups, which were found to involve 21 metabolic pathways. The distribution and abundance of gut microbiota differed significantly between patients with CRC with and without lymph node metastasis; at the genus level, the abundance of Rothia and Streptococcus was significantly higher and that of Bacteroides, Parabacteroides, and Oscillibacter was significantly lower in patients with lymph node metastasis.

CONCLUSIONS

The gut microbiota is altered in CRC patients compared with healthy individuals, with specific changes in the microbiota associated with clinical and pathological features such as tumor stage, lymph node involvement, and tumor differentiation. Our findings elaborate to some extent on the link between the gut microbiota and CRC.

Sex differences in colorectal cancer: with a focus on sex hormone-gut microbiome axis

Sexual dimorphism has been observed in the incidence and prognosis of colorectal cancer (CRC), with men generally exhibiting a slightly higher incidence than women. Research suggests that this difference may be attributed to variations in sex steroid hormone levels and the gut microbiome. The gut microbiome in CRC shows variations in composition and function between the sexes, leading to the concept of 'microgenderome' and 'sex hormone-gut microbiome axis.' Conventional research indicates that estrogens, by promoting a more favorable gut microbiota, may reduce the risk of CRC. Conversely, androgens may have a direct pro-tumorigenic effect by increasing the proportion of opportunistic pathogens. The gut microbiota may also influence sex hormone levels by expressing specific enzymes or directly affecting gonadal function. However, this area remains controversial. This review aims to explore the differences in sex hormone in CRC incidence, the phenomenon of sexual dimorphism within the gut microbiome, and the intricate interplay of the sex hormone-gut microbiome axis in CRC. The objective is to gain a better understanding of these interactions and their potential clinical implications, as well as to introduce innovative approaches to CRC treatment.

Genetically predicted gut microbiome and risk of oral cancer

PURPOSE

Mounting evidence suggests a possible link between gut microbiome and oral cancer, pointing to some potential modifiable targets for disease prevention. In the present study, Mendelian randomization (MR) was used to explore whether there was a causal link between gut microbiome and oral cancer.

METHODS

The single nucleotide polymorphisms (SNPs) significantly associated with gut microbiome were served as instrumental variables. MR analyses were performed using genetic approaches such as inverse variance weighting (IVW), MR Egger and weighted median, with IVW as the primary approach, supplemented by MR Egger and weighted median. Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO) and MR-Egger regression were used to detect the presence of horizontal pleiotropy and identify outlier SNPs.

RESULTS

Causal effect estimates indicated that genetically predicted abundance of Prevotellaceae was associated with higher risk of oral cancer (odds ratio (OR) 1.80, 95% confidence interval (CI) 1.16-2.81, p = 0.009). There was no evidence of notable heterogeneity and horizontal pleiotropy.

CONCLUSION

Genetically derived estimates suggest that Prevotellaceae may be associated with the risk of oral cancer. Such robust evidence should be given priority in future studies and explore the underlying mechanisms.

Identification of taxonomic changes in the fecal bacteriome associated with colorectal polyps and cancer: potential biomarkers for early diagnosis

Colorectal cancer (CRC) commonly arises in individuals with premalignant colon lesions known as polyps, with both conditions being influenced by gut microbiota. Host-related factors and inherent characteristics of polyps and tumors may contribute to microbiome variability, potentially acting as confounding factors in the discovery of taxonomic biomarkers for both conditions. In this study we employed shotgun metagenomics to analyze the taxonomic diversity of bacteria present in fecal samples of 90 clinical subjects (comprising 30 CRC patients, 30 with polyps and 30 controls). Our findings revealed a decrease in taxonomic richness among individuals with polyps and CRC, with significant dissimilarities observed among the study groups. We identified significant alterations in the abundance of specific taxa associated with polyps (Streptococcaceae, Lachnoclostridium, and Ralstonia) and CRC (Lactobacillales, Clostridiaceae, Desulfovibrio, SFB, Ruminococcus, and Faecalibacterium). Clostridiaceae exhibited significantly lower abundance in the early stages of CRC. Additionally, our study revealed a positive co-occurrence among underrepresented genera in CRC, while demonstrating a negative co-occurrence between Faecalibacterium and Desulfovibrio, suggesting potential antagonistic relationships. Moreover, we observed variations in taxonomic richness and/or abundance within the polyp and CRC bacteriome linked to polyp size, tumor stage, dyslipidemia, diabetes with metformin use, sex, age, and family history of CRC. These findings provide potential new biomarkers to enhance early CRC diagnosis while also demonstrating how intrinsic host factors contribute to establishing a heterogeneous microbiome in patients with CRC and polyps.

Sex and gender perspectives in colorectal cancer

Historically women were frequently excluded from clinical trials and drug usage to protect unborn babies from potential harm. As a consequence, the impact of sex and gender on both tumour biology and clinical outcomes has been largely underestimated. Although interrelated and often used interchangeably, sex and gender are not equivalent concepts. Sex is a biological attribute that defines species according to their chromosomal makeup and reproductive organ, while gender refers to a chosen sexual identity. Sex dimorphisms are rarely taken into account, in either preclinical or clinical research, with inadequate analysis of differences in outcomes according to sex or gender still widespread, reflecting a gap in our knowledge for a large proportion of the target population. Underestimation of sex-based differences in study design and analyses has invariably led to 'one-drug' treatment regimens for both males and females. For patients with colorectal cancer (CRC), sex also has an impact on the disease incidence, clinicopathological features, therapeutic outcomes, and tolerability to anticancer treatments. Although the global incidence of CRC is higher in male subjects, the proportion of patients presenting right-sided tumours and BRAF mutations is higher among females. Concerning sex-related differences in treatment efficacy and toxicity, drug dosage does not take into account sex-specific differences in pharmacokinetics. Toxicity associated with fluoropyrimidines, targeted therapies, and immunotherapies has been reported to be more extensive for females with CRC than for males, although evidence about differences in efficacy is more controversial. This article aims to provide an overview of the research achieved so far into sex and gender differences in cancer and summarize the growing body of literature illustrating the sex and gender perspective in CRC and their impact in relation to tumour biology and treatment efficacy and toxicity. We propose endorsing research on how biological sex and gender influence CRC as an added value for precision oncology.

The role of the sex hormone-gut microbiome axis in tumor immunotherapy

Accumulating evidence suggested that both gut microbiome and sex play a critical role in the efficacy of immune checkpoint blockade therapy. Considering the reciprocal relationship between sex hormones and gut microbiome, the sex hormone-gut microbiome axis may participate in the regulation of the response to immune checkpoint inhibitors (ICIs). In this review, it was attempted to summarize the current knowledge about the influences of both sex and gut microbiome on the antitumor efficacy of ICIs and describe the interaction between sex hormones and gut microbiome. Accordingly, this review discussed the potential of enhancing the antitumor efficacy of ICIs through regulating the levels of sex hormones through manipulation of gut microbiome. Collectively, this review provided reliable evidence concerning the role of the sex hormone-gut microbiome axis in tumor immunotherapy.

Sex-Dependent Differences in Colorectal Cancer: With a Focus on Obesity

Colorectal cancer (CRC) is the third most common cancer and has the second highest cancer-related mortality in the world. The incident rates of CRC vary country-wise; however, population studies and data from different countries show a general increase in the CRC rate in young adults, males, and females ≥65 years. CRC incidence is affected by age, sex, environmental, dietary, hormonal, and lifestyle factors. Obesity is a known disease that is spreading rapidly throughout the world. A large body of literature indicates that, among many conditions, obesity is the increasing cause of CRC. Even though obesity is one of the known factors for CRC development, limited studies are available that explain the mechanistic link between obesity, sex hormones, and CRC development. Thus, this review summarizes the literature and aims to understand sex-dependent differences in CRC, especially in the context of obesity.