Exploring reciprocal causation: bidirectional mendelian randomization study of gut microbiota composition and thyroid cancer.

BACKGROUND: While an association between gut microbiota composition and thyroid cancer (TC) has been observed, the directionality and causality of this relationship remain unclear. METHODS: We conducted a bidirectional two-sample Mendelian randomization (MR) analysis to investigate the causal effect between gut microbiota composition and TC. Gut microbiota data were derived from a diverse population encompassing various ethnicities (n = 18,340 samples), while TC data were sourced from an European population (n = 218,792 samples). Instrumental variables, represented by single nucleotide polymorphisms (SNPs), were employed to assess the causal relationship using multiple MR methods, including inverse-variance weighting (IVW), weighted median, weighted mode, MR-Egger, and simple mode. F-statistics and sensitivity analyses were performed to evaluate the robustness of the findings. RESULTS: Our investigation identified a comprehensive set of 2934 instrumental variables significantly linked to gut microbiota composition (p < 1 × 10-5). The analysis illuminated notable candidates within the phylum Euryarchaeota, including families Christensenellaceae and Victivallaceae, and genera Methanobrevibacter, Ruminococcus2, and Subdoligranulum, which emerged as potential risk factors for TC. On the other hand, a protective influence against TC was attributed to class Betaproteobacteria, family FamilyXI, and genera Anaerofilum, Odoribacter, and Sutterella, alongside order Burkholderiales. Further enhancing our insights, the integration of 7 instrumental variables from TC data (p < 1 × 10-5) disclosed the regulatory potential of one family and five genera. Notably, the genus Coprobacter innocuum group (p = 0.012, OR = 0.944) exhibited the highest probability of regulation. Our meticulous analyses remained free from significant bias, heterogeneity, or horizontal pleiotropy concerns. CONCLUSION: Through a bidirectional two-sample Mendelian randomization approach, we elucidated a potential bidirectional causal relationship between gut microbiota composition and TC. Specific microbial taxa were associated with an increased risk or conferred protection against TC. These findings advance our understanding of the complex interplay between the gut microbiota and TC pathogenesis, offering new insights into the therapeutic potential of modulating the gut microbiota for managing TC.

Clinical potential of microbiota in thyroid cancer therapy.

Thyroid cancer is one of the most common tumors of the endocrine system because of its rapid and steady increase in incidence and prevalence. In recent years, a growing number of studies have identified a key role for the gut, thyroid tissue and oral microbiota in the regulation of metabolism and the immune system. A growing body of evidence has conclusively demonstrated that the microbiota influences tumor formation, prevention, diagnosis, and treatment. We provide extensive information in which oral, gut, and thyroid microbiota have an effect on thyroid cancer development in this review. In addition, we thoroughly discuss the various microbiota species, their potential functions, and the underlying mechanisms for thyroid cancer. The microbiome offers a unique opportunity to improve the effectiveness of immunotherapy and radioiodine therapy thyroid cancer by maintaining the right type of microbiota, and holds great promise for improving clinical outcomes and quality of life for thyroid cancer patients.

Exploring blood metabolites and thyroid disorders: a bidirectional mendelian randomization study.

Background: Human blood metabolites have demonstrated close associations with thyroid disorders in observational studies. However, it's essential to determine whether these correlations imply causation. Mendelian Randomization (MR) offers a promising approach to investigate these patterns. Aims: The primary aim of our investigation is to establish causality between blood metabolites and three thyroid disorders: TC, GD, and HT. Methods: We employed a two-sample bidirectional MR analysis approach to assess the relationships between 452 blood metabolites and the three aforementioned thyroid disorders. Causal links were estimated using the IVW method, with sensitivity analyses conducted via MR-Egger, Weighted Median, and MR-PRESSO. We assessed potential heterogeneity and pleiotropy using MR-Egger intercept and Cochran's Q statistic. Additionally, we conducted pathway analysis to identify potential metabolic pathways. Results: We found 46 metabolites that showed suggestive associations with thyroid disease risk, especially Aspartate (ORIVW=7.41; 95%CI: 1.51-36.27; PIVW=0.013) and C-glycosyltryptophan (ORIVW=0.04; 95%CI: 0.00-0.29; PIVW=0.001) impacted TC, Kynurenine (ORIVW=2.69; 95%CI: 1.08-6.66; PIVW=0.032) and 4-androsten-3beta,17beta-diol disulfate 2 (ORIVW=0.78; 95%CI: 0.48-0.91; PIVW=0.024) significantly impacted GD, and Alpha-ketoglutarate (ORIVW=46.89; 95%CI: 4.65-473.28; PIVW=0.001) and X-14189-leucylalanine (ORIVW=0.31; 95%CI: 0.15-0.64 PIVW=0.001) significantly impacted HT. We also detected 23 metabolites influenced by TC and GD. Multiple metabolic pathways have been found to be involved in thyroid disease. Conclusion: Our MR findings suggest that the identified metabolites and pathways can serve as biomarkers for clinical thyroid disorder screening and prevention, while also providing new insights for future mechanistic exploration and drug target selection.

High-throughput Sequencing Analysis of Differentially Expressed microRNAs Associated With SREBP1 in Differentiated Thyroid Carcinoma.

BACKGROUND/AIM: MicroRNAs (miRNAs) interact with mRNAs and play important roles in progression and prognosis in multiple cancers. Sterol regulatory element-binding protein 1 (SREBP1) is an important lipid metabolism regulatory gene. The aim of the present study was to analyze the profiles of miRNAs that are associated with SREBP1 expression in differentiated thyroid carcinoma (DTC). MATERIALS AND METHODS: In the present study, a high-throughput small RNA sequencing (miRNA-Seq) method was used to investigate differences in miRNA profiling with versus without interference with SREBP1 expression via small interfering RNA. Real-time qPCR (qRT-PCR) was performed to confirm the results. RESULTS: A total of 1,393 conserved and 84 novel miRNAs were successfully discovered. In two separate batches, a total of 27 differentially expressed miRNAs (11 up-regulated and 16 down-regulated) were observed in BCPAP cells after SREBF1 interference with two distinct siRNA fragments, as compared to the control siRNA treatment. Hsa-miR-941, hsa-miR-27a-5p, hsa-miR-29a-3p, hsa-miR-100-5p, and hsa-miR-21-3p were selected for validation using qRT-PCR. The qRT-PCR results were consistent with the sequencing data. Gene Ontology enrichment showed that the predicted targets of these miRNAs were mainly involved in the regulation of system development, metabolism and protein binding cellular processes, and metabolic processes. Kyoto Encyclopedia of Genes and Genomes pathways analysis showed that the predicted target genes were involved in several signaling pathways, including the Ras, MAPK, insulin, thyroid hormone, and metabolic pathway signaling pathways. CONCLUSION: Differentially expressed miRNAs and their target genes may play an important role in the progression and prognosis of DTC that is associated with SREBP1 expression.

Predicting the occurrence of multidrug-resistant organism colonization or infection in ICU patients: development and validation of a novel multivariate prediction model.

BACKGROUND: Multidrug-resistant organisms (MDROs) have emerged as an important cause of poor prognoses of patients in the intensive care unit (ICU). This study aimed to establish an easy-to-use nomogram for predicting the occurrence of MDRO colonization or infection in ICU patients. METHODS: In this study, we developed a nomogram based on predictors in patients admitted to the ICU in the First Affiliated Hospital of Xiamen University from 2016 to 2018 using univariate and multivariate logistic regression analysis. We externally validated this nomogram in patients from another hospital over a similar period, and assessed its performance by calculating the area under the receiver operating characteristic (ROC) curve (AUC) and performing a decision curve analysis. RESULTS: 331 patients in the primary cohort and 181 patients in the validation cohort were included in the statistical analysis. Independent factors derived from the primary cohort to predict MDRO colonization or infection were male sex, higher C-reactive protein (CRP) levels and higher Pitt bacteremia scores (Pitt scores), which were all assembled in the nomogram. The nomogram yielded good discrimination with an AUC of 0.77 (95% CI 0.70-0.84), and the range of threshold probabilities of decision curves was approximately 30-95%. CONCLUSION: This easy-to-use nomogram is potentially useful for predicting the occurrence of MDRO colonization or infection in ICU patients.

[Effects of exogenous hydrogen sulfide on intestinal function in rabbits after cardiopulmonary resuscitation].

OBJECTIVE: To investigate the effect of exogenous hydrogen sulfide (H2S) on intestinal mucosal barrier after cardiopulmonary resuscitation (CPR) in cardiac arrest (CA) rabbits. METHODS: Forty-four male New Zealand rabbits were divided into sham operation group (Sham group, n = 12), post-cardiac arrest syndrome (PCAS) group (n = 16) and H2S intervention group (PCAS+NaHS, n = 16) according to random number table method. The rabbit model of PCAS was established by tracheal clamping and suffocation, and CPR was started at 5 minutes after CA. However, Sham group did not clamp the tracheal intubation after anesthesia, and the other operations were the same as those in PCAS group. In the PCAS+NaHS group, a bolus of NaHS (0.5 mg/kg), a H2S donor, was injected via era vein 1 minute before the start of CPR, followed by a continuous injection of NaHS (1.5 mg×kg-1×h-1) for 3 hours, while the rabbits in other group were intravenously injected with the same volume of normal saline (NaCl 0.9%). Intestinal and portal vein blood samples were collected 24 hours after return of spontaneous circulation (ROSC). The level of serum fluorescein isothiocyanate-dextran (FD-4) was detected by fluorescein isothiocyanate (FITC) labeling method to reflect intestinal mucosal permeability. After hematoxylin-eosin (HE) staining of small intestine tissues, the morphological changes of mucosa were observed under light microscope, and the intestinal mucosa injury score was calculated. The expression of tight junction protein ZO-1 in intestinal mucosa was detected by immunohistochemistry. The content of malondialdehyde (MDA) in small intestinal tissue was determined by thiobarbituric acid chromogenic method, the activity of superoxide dismutase (SOD) was determined by xanthine oxidation method, and the level of myeloperoxidase (MPO) was determined by double antibody sandwich enzyme linked immunosorbent assay (ELISA) to reflect the oxidative stress and inflammatory reaction in small intestinal tissue. The expression of apoptosis protein (caspase-3) and autophagy related protein (Beclin-1, LC3) in small intestine tissue was detected by Western Blot. RESULTS: 12, 13 and 14 animals were successfully resuscitated in Sham group, PCAS group and PCAS+NaHS group respectively, while 12 animals in each group survived to the end of experiment. Compared with Sham group, the level of FD-4 in portal vein serum was significantly increased in PCAS group (mg/L: 11.95±0.59 vs. 1.43±0.48, P < 0.05), the pathological injury and inflammation infiltration were obviously aggravated under light microscope, the score of small intestine injury was significantly increased (4.21±0.37 vs. 0.36±0.18, P < 0.05), the expression of tight junction protein ZO-1 in the intestine was visibly down-regulated detected by immunohistochemistry, MDA content and MPO activity were significantly increased [MDA (nmol/mg): 3.65±0.32 vs. 1.54±0.24, MPO (U/g): 362±35 vs. 134±18, both P < 0.05], while SOD activity was significantly decreased (U/mg: 78.84±7.49 vs. 115.48±8.48, P < 0.05), the expression levels of cleaved capase-3, Beclin-1 and LC3 proteins in the intestine were significantly increased (caspase-3/ß-actin: 1.11±0.08 vs. 0.21±0.02, Beclin-1/ß-actin: 2.08±0.11 vs. 0.42±0.03, LC3/ß-actin: 1.05±0.07 vs. 0.37±0.05, LC3-II/LC3-I: 1.28±0.14 vs. 0.17±0.02, all P < 0.05). Compared with PCAS group, the portal vein serum FD-4 level in PCAS+NAHS group was significantly decreased (mg/L: 5.59±0.48 vs. 11.95±0.59, P < 0.05), the intestinal mucosal pathological injury and inflammatory cell infiltration were significantly decreased, the score of small intestine injury was significantly decreased (2.18±0.47 vs. 4.21±0.37, P < 0.05), the expression of ZO-1 in intestine was significantly increased, MDA content and MPO activity in intestine were significantly decreased [MDA (nmol/mg): 2.65±0.31 vs. 3.65±0.32, MPO (U/g): 251±21 vs. 362±35, both P < 0.05], while SOD activity was significantly increased (U/mg: 96.86±7.52 vs. 78.84±7.49, P < 0.05), while the expression of activated caspase-3, Beclin-1 and LC3 proteins was significantly decreased (caspase-3/ß-actin: 0.72±0.06 vs. 1.11±0.08, Beclin-1/ß-actin: 0.96±0.08 vs. 2.08±0.11, LC3/ß-actin: 0.72±0.06 vs. 1.05±0.07, LC3-II/LC3-I: 0.83±0.09 vs. 1.28±0.14, all P < 0.05). CONCLUSIONS: H2S has a protective effect on intestinal mucosal injury induced by CA/CPR, which may be related to tight junction protein ZO-1 up-regulation, oxidative stress alleviation, inflammation reduction, apoptosis and autophagy inhibition.