Alteration of indicator gut microbiota in patients with chronic sinusitis

Dissecting the causal links between gut microbiome, immune traits and polyp using genetic evidence

Background

Previous research has demonstrated an association between gut microbiota and immune status with the development of several diseases. However, whether these factors contribute to polyps remains unclear. This study aims to use Mendelian randomization (MR) to investigate the causal relationship between gut microbiota and 4 types of polyps (nasal, gallbladder, colon, and gastric polyps), as well as to analyze the mediating role of immune traits.

Methods

This study utilized large-scale GWAS meta-analyses of gut microbiota (MiBioGen Consortium), 731 immune traits, and 4 types of polyps (one from the FinnGen Consortium and three from the NBDC Human Database). Univariate MR with the inverse variance weighted (IVW) estimation method was employed as the primary analytical approach. A two-step MR analysis was performed to identify potential mediating immune traits. Additionally, multivariable MR approach based on Bayesian model averaging (MR-BMA) was employed to further prioritize gut microbiota and immune traits associated with polyp development.

Results

Based on IVW method in univariate MR analysis, we identified 39 gut microbial taxa and 135 immune traits significantly causally associated with at least one type of polyp. For nasal polyps, 13 microbial taxa and 61 immune traits were causally associated. After false discovery rate (FDR) correction, CD3 on Central Memory CD8+ T cells and CD3 on CD4 regulatory T cells remained significant. MR-BMA identified 4 gut microbial taxa and 4 immune traits as high priority. For gallbladder polyps, 9 microbial taxa and 30 immune traits were causally associated. MR-BMA identified 8 microbial taxa and 6 immune traits as higher importance. For colon polyps, 6 microbial taxa and 21 immune traits were causally associated. MR-BMA identified 4 microbial taxa and 3 immune traits as higher importance. For gastric polyps, 12 microbial taxa and 33 immune traits were causally associated. Actinobacteria remained significant after FDR correction, and MR-BMA identified 7 gut microbial taxa and 6 immune traits as high priority. We identified 16 causal pathways with mediator directions consistent with the direction of gut microbiome-polyp association. Of these, 6 pathways were associated with the mechanism of nasal polyps, 1 with gallbladder polyps, 2 with colon polyps, and 7 with gastric polyps.

Conclusions

Our findings shed light on the causal relationships between gut microbiota, immune traits, and polyp development, underscoring the crucial roles of gut microbiota and immune status in polypogenesis. Furthermore, these findings suggest potential applications in polyp prevention, early screening, and the development of effective strategies to reduce polyp risk.

Associations between gut microbiota and chronic sinusitis: A bidirectional Mendelian randomization study

BACKGROUND

Studies have indicated a close association between dysbiosis of the gut microbiota and chronic sinusitis. However, the causal relationship between the gut microbiota and the risk of chronic sinusitis remains unclear.

METHODS

Using genome-wide association study (GWAS) data for the gut microbiota and chronic sinusitis, we conducted a two-sample Mendelian randomization (MR) study to determine the potential causal relationship between the microbiota and chronic sinusitis. We employed the inverse variance-weighted (IVW) method as the primary analytical approach to estimate the effect. Additionally, sensitivity, heterogeneity, and pleiotropy analyses were conducted to evaluate the robustness of the results. Reverse MR analysis was also applied to investigate potential reverse causality.

RESULTS

Through MR analysis, we identified 17 gut microbiota classifications that are closely associated with chronic sinusitis. However, after Bonferroni multiple correction, only class Bacilli (odds ratio: 0.785, 95% confidence interval: 0.677-0.911, p = .001, false discovery rate = 0.023) maintained a significant causal negative relationship with chronic sinusitis. Sensitivity analysis did not reveal any evidence of heterogeneity or horizontal pleiotropy. Reverse MR analysis found five gut microbiota classifications that are significantly associated with chronic sinusitis, but they were no longer significant after Bonferroni multiple correction. There was no evidence to suggest a reverse causal relationship between chronic sinusitis and class Bacilli.

CONCLUSION

Specific gut microbiota predicted by genetics exhibit a potential causal relationship with chronic sinusitis, and class Bacilli may have a protective effect on chronic sinusitis.

Higher Risk of Rheumatoid Arthritis in Patients With Chronic Rhinosinusitis: Prospective Association in the U.K. Biobank and Genetic Evidence by Mendelian Randomization Analysis

BACKGROUND

Previous studies have shown that respiratory diseases are associated with an increased risk of rheumatoid arthritis (RA). However, whether there is a correlation between chronic rhinosinusitis (CRS) and RA is not known. Due to the high incidence of CRS, it remains to be clarified whether we should pay additional attention to RA risk in the huge population of CRS.

METHODS

We used a 2-sample Mendelian randomization (MR) analysis to explore the causal effects of CRS on the incidence of RA. The inverse variance weighted (IVW) approach was used as the main analysis in the MR randomization study. Then, we used the data from the U.K. Biobank to examine the association between RA and CRS at the individual level in a prospective cohort. We identified patients with CRS at the time of recruitment and further followed the incidence of RA until 2021. The risk of developing RA in patients with CRS was determined by a multivariate Cox regression model. We used 3 multivariate Cox models to adjust for individual characteristics, lifestyle factors and concomitant diseases, respectively.

RESULTS

The MR analysis by the IVW model suggested that the odds ratio of RA associated with genetically predicted CRS was 2.39 (95% CI [1.08-5.30]; p  =  .032). In the first multivariate model adjusting for individual characteristics, CRS was associated with a 47% increase of risk of developing RA (hazard ratio [HR]  =  1.47; 95% CI [1.12-1.90]). In the second multivariate model adjusting for lifestyle factors, the HR of RA associated with CRS was 1.48 (95% CI [1.15-1.90]). In the third multivariate model, chronic sinusitis was associated with a 32% increase in RA risk (HR  =  1.32; 95% CI [1.03-1.70]).

CONCLUSION

CRS has a genetically causal effect on the incidence of RA, and the risk of RA is greatly higher in CRS at the individual level. This is the first study to reveal an association between CRS and RA. Due to the high incidence of CRS, it is recommended that additional attention should be paid to the increased RA risk in patients with CRS compared to that in common people.