The Innovative Approach in Functional Bladder Disorders: The Communication Between Bladder and Brain-Gut Axis

Microbiome and bladder cancer: the role of probiotics in treatment

Bladder cancer (BCa) remains a significant global health challenge, with increasing interest in the role of the bladder microbiome in its pathogenesis, progression and treatment outcomes. The complex relationship between bladder cancer and the microbiome, as well as the potential impact of probiotics on treatment effectiveness, is currently under investigation. Research suggests that the microbiota may influence BCa recurrence prevention and enhance the efficacy of the Bacillus Calmette-Guérin (BCG) vaccine. Recent studies reveal differences in the bladder microbiome between individuals without bladder cancer and those with the disease. In the healthy bladder, Streptococcus and Lactobacillus are consistently identified as the most prevalent genera. However, in men, the predominant bacterial genera are Staphylococcus, Corynebacterium and Streptococcus, while in women with bladder cancer, Gardnerella and Lactobacillus are dominant. Probiotics, particularly Lactobacillus spp., can exhibit anti-tumor properties by competing with pathogenic strains involved in carcinogenesis or by producing regulatory substances. They regulate cancer signaling, induce apoptosis, inhibit mutagenic activity, downregulate oncogene expression, induce autophagy, inhibit kinases, reactivate tumor suppressors and prevent metastasis. These mechanisms have shown promising results in both preclinical and some clinical studies.

Causal effects of gut microbiota on risk of overactive bladder symptoms: a two-sample Mendelian randomization study

Background

Clinical observations indicate a correlation between the gut microbiota and overactive bladder (OAB) symptoms. Nevertheless, the causal relationship and mechanisms between gut microbiota and OAB symptoms remain elusive.

Methods

Two-sample Mendelian randomization (MR) analyses were performed to assess the association between gut microbiota and OAB symptoms, including urinary incontinence (UI). Data were obtained from the MiBioGen International Consortium genome-wide association studies (GWAS) dataset and the IEU GWAS database. The inverse variance weighted method was used as the primary approach in the MR analysis, with the weighted median, MR-Egger, and weighted mode methods as supplementary approaches. Sensitivity analyses were employed to assess potential violations of the MR assumptions.

Results

Our analysis identified seven gut bacterial taxa with a causal relationship to OAB and nine gut bacterial taxa associated with UI. Genera Eubacteriumfissicatenumgroup, LachnospiraceaeNK4A136group, and Romboutsia were identified as protective factors against OAB, while genera Barnesiella, FamilyXIIIAD3011group, Odoribacter, and RuminococcaceaeUCG005 were associated with an increased risk of OAB. A higher abundance of the genus Coprococcus3, order Burkholderiales, and phylum Verrucomicrobia predicted a lower risk of UI. Conversely, the class Mollicutes, genus Ruminococcus gauvreauii group, order Mollicutes RF9, and phylum Firmicutes and Tenericutes were positively correlated with UI risk. The sensitivity analysis excluded the influence of potential heterogeneity and horizontal pleiotropy.

Conclusion

This study revealed a causal relationship between gut microbiota and OAB symptoms, providing new insights and a theoretical foundation to identify biomarkers and therapeutic targets for patients with OAB symptoms.

Mendelian randomization study reveals causal effects of specific gut microbiota on the risk of interstitial cystitis/bladder pain syndrome (IC/BPS)

Evidence from previous studies have demonstrated that gut microbiota are closely associated with occurrence of interstitial cystitis/bladder pain syndrome (IC/BPS), yet the causal link between the two is not well known. In this study, we performed a two-sample Mendelian randomization (MR) analysis to determine the possible causal association between gut microbiota with IC/BPS. Gut microbiota summary level data were derived from the genome-wide association study (GWAS) conducted by MiBioGen and the IC/BPS GWAS summary level data were obtained from the GWAS Catalog. Next, we performed an MR study to investigate the causal link between gut microbiota and IC/BPS. The primary method for causal analysis was the inverse variance weighted (IVW), and the MR results were validated through multiple sensitivity analyses. A positive association was found between IC/BPS and eight gut microbial taxa, including genus Bacteroides, genus Haemophilus, genus Veillonella, genus Coprococcus1, genus Butyricimonas, family Bacteroidaceae, family Christensenellaceae, and order Lactobacillales. Sensitivity analysis revealed lack of significant pleiotropy or heterogeneity in the obtained results. This MR analysis reveals that a causal association exists between some gut microbiota with IC/BPS. This finding may is expected to guide future research and development of IC/BPS preventions and treatments based on the bladder-gut axis. However, given the clinical complexity and diagnostic challenges of IC/BPS, along with the limitations of using large-scale GWAS summary data for analysis, our MR results require further validation through additional research.

Does COVID-19 cause or worsen LUT dysfunction, what are the mechanisms and possible treatments? ICI-RS 2023

INTRODUCTION

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19) and produced a worldwide pandemic in 2020. There have been 770,875,433 confirmed cases and 6,959,316 attributed deaths worldwide until September 19, 2023. The virus can also affect the lower urinary tract (LUT) leading to bladder inflammation and producing lower urinary tract symptoms (LUTS) in both the acute and chronic phases of disease.

METHODS

At the 2023 meeting of the International Consultation on Incontinence-Research Society (ICI-RS), the literature relating to COVID-19 and bladder dysfunction was reviewed. The LUTS reported, as well as the pathophysiology of these bladder symptoms, were the subject of considerable discussion. A number of different topics were discussed including lower LUTS reported in COVID-19, how SARS-CoV-2 may infect and affect the urinary tract, and proposed mechanisms for how viral infection result in new, worsened, and in some persisting LUTS.

CONCLUSIONS

The workshop discussed the interaction between the virus and the immune system, covering current evidence supporting theories underlying the causes of acute and chronic LUTS related to COVID-19 infection. Research questions for further investigation were suggested and identified.

Causal effects of gut microbiota on risk of interstitial cystitis: a two-sample Mendelian randomization study

Background

The correlation between gut microbiota and interstitial cystitis has garnered significant attention in previous studies. Nevertheless, the causal relationship between them remains to be clarified.

Methods

Genetic variation serves as a tool in Mendelian randomization analyses, facilitating the inference of causal relationships between exposure factors and disease outcomes. In this study, summary statistics derived from a comprehensive genome-wide association study conducted by the MiBioGen consortium were utilized as exposure factors, while interstitial cystitis data sourced from the GWAS Catalog served as the disease outcome. Then, a two-sample Mendelian randomization analysis was performed by applying inverse variance-weighted, MR-Egger, Weighted Median, Simple Mode, and Weighted Mode. In addition, heterogeneity and horizontal pleiotropy were excluded by sensitivity analysis.

Results

IVW results confirmed that genus Haemophilus (OR = 2.20, 95% CI: 1.16-4.15, p = 0.015), genus Butyricimonas (OR = 2.26, 95% CI: 1.15-4.45, p = 0.018), genus Bacteroides (OR = 4.27, 95% CI: 1.36-13.4, p = 0.013) and Coprococcus1 (OR = 3.39, 95% CI: 1.28-8.99, p = 0.014) had a risk effect on interstitial cystitis. Sensitivity analysis did not find outlier SNPs.

Conclusion

Our analysis has identified a causal relationship between specific genera and interstitial cystitis. However, further validation through randomized controlled trials is essential to substantiate these findings.

Association between overactive bladder and depression in American adults: A cross-sectional study from NHANES 2005-2018

BACKGROUND AND AIM

Overactive bladder (OAB) and depression are both common disorders and there is research suggesting an association between the two, but there is a lack of studies with large samples. The aim of this study is to investigate the association between OAB and depressive symptoms.

METHODS

We used data from the National Health and Nutrition Examination Survey (NHANES) database for the period 2005 to 2018. OAB was characterized by the Overactive Bladder Symptom Score (OABSS, score > 3) and depression was diagnosed by the Patient Health Questionnaire (PHQ-9, score ≥ 10). There were three models employed in our analysis: (1) Crude model was unadjusted; (2) Model 1 was adjusted for age, sex, race/ethnicity, educational level, and marital status; (3) Model 2 was adjusted for factors in Model 1 plus the remained potential covariates. We used survey-weighted logistic regression models to assess the association between OAB and depression. Subsequently, subgroup analyses and smoothed curve analyses were used to evaluate the reliability of the findings.

RESULTS

Finally, a total of 6612 participants were included in our study, consisting of 1005 participants with diagnosis of OAB and 5607 participants without diagnosis of OAB. After adjusting for all covariates, there was a significant positive association between OAB and depression (OR: 2.89, 95 % CI: 1.91, 4.37). The severity of OAB was also positively associated with depression. Compared to participants without OAB, the fully adjusted ORs for depression were 2.76 (95 % CI: 1.64, 4.65) for those with mild OAB, 3.79 (95 % CI: 1.68, 8.55) for those with moderate OAB, and 5.21 (95 % CI: 1.39, 19.53) for those with severe OAB.

CONCLUSIONS

This study revealed a strong association between OAB and depression and a progressive increase in the risk of depression as the severity of OAB (mild, moderate, and severe) increased. Therefore, it is important for clinicians to recognize the assessment of OAB symptoms in patients who are at risk for or have developed depressive symptoms, as well as the mental health of patients with OAB.