The causal relationship between gut microbiota and neuroblastoma: a bidirectional Mendelian randomization analysis and meta-analysis.

Neuroblastoma (NB) is a type of neuroectodermal tumor that originates from primitive sympathetic ganglion cells. Although many risk factors contributing to the occurrence of NB have been reported in recent years, the role of the gut microbiota in its development remains unclear. A bidirectional Mendelian randomization (MR) analysis was conducted to elucidate the causal relationship between the gut microbiota and NB. In the MR analysis, we employed the inverse-variance weighted (IVW) method as the primary criterion for assessing causality, while also utilizing three additional approaches, including MR-Egger, weighted median model, and weighted mode, for comprehensive evaluation. For gut microbiota that were causally associated with NB, a reverse MR was also used to assess the stability of this causal relationship. Finally, we also used external cohorts for validation and performed a meta-analysis of the results. The IVW results indicated a causal relationship between six gut microbiota and NB. Among the six gut microbiota, genus Lachnospiraceae [IVW odds ratio (OR): 2.66, 95% confidence interval (CI): 1.09-6.51, P value: 0.03] exhibited a detrimental effect against NB. On the other hand, the class Actinobacteria (IVW OR: 0.24, 95% CI: 0.07-0.77, P value: 0.02), the family Bifidobacteriaceae (IVW OR: 0.40, 95% CI: 0.17-0.96, P value: 0.04), the genus Desulfovibrio (IVW OR: 0.50, 95% CI: 0.25-0.97, P value: 0.04), the genus Bifidobacterium (IVW OR: 0.39, 95% CI: 0.16-0.92, P value: 0.03), and the genus Howardella (IVW OR: 0.55, 95% CI: 0.31-0.97, P value: 0.04) displayed a protective effect on NB. A reverse MR analysis did not reveal a causality between NB and the six gut microbiota. Meta-analysis showed that genus Bifidobacterium (meta OR: 0.41, 95% CI: 0.22-0.75, P < 0.01) and genus Lachnospiraceae (meta OR: 2.20, 95% CI: 1.01-4.79, P < 0.05) were still significant. IMPORTANCE: Bidirectional Mendelian randomization was used to explore the causality between gut microbiota and neuroblastoma (NB). The results showed that there is a causal relationship between the six gut microbiota and NB, of which two gut microbiota were further confirmed in the meta-analysis. This may provide a new perspective on the prevention and treatment of NB.

Adsorption and desorption of Hg(II) by four aged microplastics and its effects on gaseous elemental mercury production in seawater.

Microplastics (MPs) weather after entering the environment gradually, and the interaction with metal ions in the aqueous environment has received extensive attention. However, there are few studies on Hg(Ⅱ), especially the effect of MPs on the release of Hg0(DEM) in water after entering the aqueous environment. In this study, four types of MPs (PP, PE, PET, PVC) were selected to study the adsorption and desorption behavior of Hg(Ⅱ) after photoaging and to explore the influence of MPs on the release of DEM in seawater under different lighting conditions. The results showed that the specific surface area, negative charges, and oxygen-containing functional group of MPs increased after aging. The adsorption capacity of aged MPs for Hg(Ⅱ) was significantly improved, which was consistent with the pseudo-first-order and pseudo-second-order model, indicating that the adsorption process was a chemical and physical adsorption. The fitting results of the in-particle diffusion model indicated that the adsorption was controlled by multiple steps. Hg(Ⅱ) was easier to desorb in the simulated gastric fluid environment. Because the aged MPs had the stronger binding force to Hg(Ⅱ), their desorption rate is lower than new MPs. Under visible light and UVA irradiation, MPs inhibited the release of Hg0. Under UVA, the mass of DEM produced in seawater with aged PE and PVC was higher than that of new PE and PVC. The aged PE and PVC could produce more ·O2-, which was conducive to the reduction of mercury. However, in UVB irradiation, the addition of MPs promoted the release of DEM, and ·O2- also played an important contribution in affecting the photochemical reaction of mercury. Therefore, the presence of aged MPs will significantly affect the water-air exchange of Hg in water. Compared with new MPs, aged MPs improved the contribution of free radicals in Hg transformation by releasing reactive oxygen species. This study extends the understanding of the effects of MPs on the geochemical cycle of Hg(Ⅱ) in seawater, better assesses the potential combined ecological risks of MPs and Hg(Ⅱ), and provides certain guidance for the pollution prevention and control of MPs.

The cause-and-effect relationship between gut microbiota abundance and carcinoid syndrome: a bidirectional Mendelian randomization study.

Objective: Carcinoid syndrome (CS) commonly results from neuroendocrine tumors. While active substances are recognized as the main causes of the typical symptoms such as diarrhea and skin flush, the cause-and-effect relationship between gut microbiota abundance and CS remains unclear. Methods: The Single Nucleotide Polymorphisms (SNPs) related to gut microbiota abundance and CS were obtained from the GWAS summary data. The inverse variance weighted (IVW) method was used to assess the causal relationship between gut microbiota abundance and CS. Additionally, the MR-Egger, Weighted Median model, and Weighted model were employed as supplementary approaches. The heterogeneity function of the TwoSampleMR package was utilized to assess whether SNPs exhibit heterogeneity. The Egger intercept and Presso test were used to assess whether SNPs exhibit pleiotropy. The Leave-One-Out test was employed to evaluate the sensitivity of SNPs. The Steiger test was utilized to examine whether SNPs have a reverse causal relationship. A bidirectional mendelian randomization (MR) study was conducted to elucidate the inferred cause-and-effect relationship between gut microbiota abundance and CS. Results: The IVW results indicated a causal relationship between 6 gut microbiota taxa and CS. Among the 6 gut microbiota taxa, the genus Anaerofilum (IVW OR: 0.3606, 95%CI: 0.1554-0.8367, p-value: 0.0175) exhibited a protective effect against CS. On the other hand, the family Coriobacteriaceae (IVW OR: 3.4572, 95%CI: 1.0571-11.3066, p-value: 0.0402), the genus Enterorhabdus (IVW OR: 4.2496, 95%CI: 1.3314-13.5640, p-value: 0.0146), the genus Ruminiclostridium6 (IVW OR: 4.0116, 95%CI: 1.2711-12.6604, p-value: 0.0178), the genus Veillonella (IVW OR: 3.7023, 95%CI: 1.0155-13.4980, p-value: 0.0473) and genus Holdemanella (IVW OR: 2.2400, 95%CI: 1.0376-4.8358, p-value: 0.0400) demonstrated a detrimental effect on CS. The CS was not found to have a reverse causal relationship with the above 6 gut microbiota taxa. Conclusion: Six microbiota taxa were found to have a causal relationship with CS, and further randomized controlled trials are needed for verification.