Gut microbiota-brain bile acid axis orchestrates aging-related neuroinflammation and behavior impairment in mice.

Emerging evidence shows that disrupted gut microbiota-bile acid (BA) axis is critically involved in the development of neurodegenerative diseases. However, the alterations in spatial distribution of BAs among different brain regions that command important functions during aging and their exact roles in aging-related neurodegenerative diseases are poorly understood. Here, we analyzed the BA profiles in cerebral cortex, hippocampus, and hypothalamus of young and natural aging mice of both sexes. The results showed that aging altered brain BA profiles sex- and region- dependently, in which TßMCA was consistently elevated in aging mice of both sexes, particularly in the hippocampus and hypothalamus. Furthermore, we found that aging accumulated-TßMCA stimulated microglia inflammation in vitro and shortened the lifespan of C. elegans, as well as behavioral impairment and neuroinflammation in mice. In addition, metagenomic analysis suggested that the accumulation of brain TßMCA during aging was partially attributed to reduction in BSH-carrying bacteria. Finally, rejuvenation of gut microbiota by co-housing aged mice with young mice restored brain BA homeostasis and improved neurological dysfunctions in natural aging mice. In conclusion, our current study highlighted the potential of improving aging-related neuro-impairment by targeting gut microbiota-brain BA axis.

Association between metabolic dysfunction-associated steatotic liver disease and risk of colorectal cancer or colorectal adenoma: an updated meta-analysis of cohort studies.

Background and aims: In recent years, the relationship between metabolic dysfunction-associated steatotic liver disease (MASLD) and colorectal cancer (CRC) or colorectal adenoma (CRA) has gained widespread attention. Previous meta-analyses on this subject either incorporated numerous cross-sectional studies, which were susceptible to bias, or concentrated solely on a restricted number of cohort studies. Moreover, with the release of a substantial number of high-quality cohort studies on this subject in the past two years, the findings continue to be debated and contradictory. Therefore, we conducted an updated systematic review and meta-analysis of cohort studies to quantitatively evaluate the magnitude of the association between them. Methods: Comprehensive searches of PubMed, Web of Science, and Embase were conducted without language restrictions from the time of their creation up to December, 2023. The pooled hazard ratios (HRs) with 95% confidence interval (CIs) were calculated by the generic inverse variance based on the random-effects model. Moreover, subgroup and sensitivity analyses were performed. Results: A total of 15 cohort studies were analyzed in this meta-analysis, which included 9,958,412 participants. The meta-analysis of 13 cohort studies showed that MASLD was linked to a higher risk of CRC (HR=1.25, 95% CI: 1.15-1.36, P < 0.00001). Additionally, further subgroup analysis indicated that the combined HR remained consistent regardless of the study location, nomenclature of fatty liver disease (FLD), confirmation methods for FLD, sample size, follow-up time, and study quality. Furthermore, the meta-analysis of four cohort studies demonstrated that MASLD was correlated with an increased risk of CRA (HR=1.38, 95% CI: 1.17-1.64, P = 0.0002). The sensitivity analysis results further validated the robustness of the aboved findings. Conclusion: The results of our meta-analysis indicated that MASLD was associated with an increased risk of incident CRC/CRA. In the future, it is necessary to conduct more prospective cohort studies to thoroughly assess potential confounding factors, particularly in individuals from Europe and North America. Furthermore, related mechanism studies should be conducted to enhance our understanding of the link between MASLD and CRC/CRA. Systematic review registration: Open Science Framework registries (https://osf.io/m3p9k).

Association of MASLD with the risk of extrahepatic cancers: A systematic review and meta-analysis of 18 cohort studies.

BACKGROUND: Numerous recent studies have explored the association between metabolic dysfunction-associated steatotic liver disease (MASLD) and the risk of various extrahepatic cancers. However, the conclusions were inconclusive. The aim of this study was to clarify this relationship by conducting a robust meta-analysis. METHODS: Systematic searches were conducted on PubMed, Embase and Web of Science databases to identify relevant cohort studies published prior to February 2024. Hazard ratios (HRs) and their corresponding 95% confidence intervals (95% CIs) were combined using a random-effects model in this meta-analysis. RESULTS: Eighteen cohort studies (approximately 16.7 million participants) were finally included in this meta-analysis. MASLD was linked to a higher risk of extrahepatic cancers, such as gastric (n = 10, HR = 1.47, 95% CI: 1.07-2.01), colorectal (n = 13, HR = 1.33, 95% CI: 1.16-1.53), pancreatic (n = 8, HR = 1.41, 95% CI: 1.11-1.79), biliary tract (n = 5, HR = 1.27, 95% CI: 1.18-1.37), thyroid (n = 6, HR = 1.46, 95% CI: 1.02-2.09), urinary system (n = 10, HR = 1.45, 95% CI: 1.25-1.69), breast (n = 11, HR = 1.17, 95% CI: 1.08-1.26) and female genital organ cancers (n = 10, HR = 1.36, 95% CI: 1.11-1.66). However, there was no statistically significant association between MASLD and the risk of head and neck (n = 6, HR = 1.03, 95% CI: 99-1.07), oesophageal (n = 9, HR = 1.26, 95% CI: 0.86-1.86), lung (n = 9, HR = 1.01, 95% CI: 0.92-1.10), prostate (n = 9, HR = 1.06, 95% CI: 0.94-1.19) or small intestine cancer (n = 2, HR = 1.75, 95% CI: 1.00-3.06). CONCLUSIONS: This latest large-scale meta-analysis indicated that MASLD was associated with an increased risk of various extrahepatic cancers, such as gastric, colorectal, pancreatic, biliary duct, thyroid, urinary system, breast, skin and female genital cancers. Further research is needed to investigate the mechanisms underlying these associations.

Hepatic IRE1α-XBP1 signaling promotes GDF15-mediated anorexia and body weight loss in chemotherapy.

Platinum-based chemotherapy drugs can lead to the development of anorexia, a detrimental effect on the overall health of cancer patients. However, managing chemotherapy-induced anorexia and subsequent weight loss remains challenging due to limited effective therapeutic strategies. Growth differentiation factor 15 (GDF15) has recently gained significant attention in the context of chemotherapy-induced anorexia. Here, we report that hepatic GDF15 plays a crucial role in regulating body weight in response to chemo drugs cisplatin and doxorubicin. Cisplatin and doxorubicin treatments induce hepatic Gdf15 expression and elevate circulating GDF15 levels, leading to hunger suppression and subsequent weight loss. Mechanistically, selective activation by chemotherapy of hepatic IRE1α-XBP1 pathway of the unfolded protein response (UPR) upregulates Gdf15 expression. Genetic and pharmacological inactivation of IRE1α is sufficient to ameliorate chemotherapy-induced anorexia and body weight loss. These results identify hepatic IRE1α as a molecular driver of GDF15-mediated anorexia and suggest that blocking IRE1α RNase activity offers a therapeutic strategy to alleviate the adverse anorexia effects in chemotherapy.

Association between metabolic dysfunction-associated steatotic liver disease and risk of incident pancreatic cancer: a systematic review and meta-analysis of cohort studies.

Background and objectives: Since the results of previous observational studies on the relationship between metabolic dysfunction-associated steatotic liver disease (MASLD) and pancreatic cancer were still controversial and inconsistent, we performed a systematic evaluation and meta-analysis of cohort studies to assess any potential association. Methods: We conducted a systematic search of PubMed, Embase, and Web of Science databases from the database's inception up to November 30, 2023. For summary purposes, hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using random-effects models, and subgroup and sensitivity analyses were performed as well. The Egger's test and Begg's test were utilized to detect the publication bias. Results: This meta-analysis included nine cohort studies with a total of 10,428,926 participants. The meta-analysis demonstrated an increased risk of pancreatic cancer in those with MASLD (HR = 1.32, 95% CI: 1.10-1.59, P = 0.003) with moderate heterogeneity (I2 = 54%, P = 0.03). Subsequent subgroup analyses revealed that the pooled HRs remained significantly unchanged, irrespective of the study area, nomenclature of fatty liver disease, and sample size. The results of the sensitivity analyses remained unchanged. No evidence of publication bias was found. Conclusion: This meta-analysis indicated that MASLD was associated with a higher risk of pancreatic cancer. To further strengthen the association, future prospective cohort studies should take into account different ethnic groups, diagnostic methods of fatty liver, the severity of MASLD, and potential confounding factors, as well as explore the potential mechanisms of pancreatic cancer development in MASLD patients. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42023489137.

Non-alcoholic fatty liver disease and gestational diabetes mellitus: a bidirectional two-sample mendelian randomization study.

PURPOSE: Previous observational studies have revealed a potential link between non-alcoholic fatty liver disease (NAFLD) and gestational diabetes mellitus (GDM), but their causal relationship remains unclear. Thus, this study aimed to examine whether a causal link exists between genetically determined NAFLD and GDM. METHODS: Utilizing publicly accessible genome-wide association studies (GWAS), a two-sample bidirectional Mendelian randomization (MR) analysis was conducted. The GWASs data pertaining to NAFLD and GDM were obtained from the UK Biobank Consortium and FinnGen database in primary analysis, respectively. The random-effects inverse variance weighted (IVW) method was utilized as primary analysis method. Several sensitivity analyses were utilized to verify the robustness of the results. Additionally, we also analyzed the causal effect of potential shared influencing factors on these two conditions. RESULTS: The result of the IVW method showed that there was no significant causal relationship between genetically determined NAFLD and GDM (OR = 0.98, 95% CI: 0.90-1.07, P = 0.691). Similarly, our reverse MR analysis failed to detect a significant causal effect of GDM on NAFLD (OR = 1.14, 95% CI: 0.97-1.36, P = 0.118). Sensitivity analyses further confirmed the robustness of the results. Moreover, we found that genetically determined body mass index, waist-to-hip ratio, triglycerides, and television viewing time may be positively correlated with NAFLD and GDM, while high-density lipoprotein cholesterol and apolipoprotein A-I may both be negatively correlated with NAFLD and GDM. CONCLUSIONS: The current bidirectional MR study failed to provide sufficient genetic evidence for the causal relationship between NAFLD and GDM.