Relationship between gut microbiota and vascular calcification in hemodialysis patients

Bacillus siamensis Improves the Immune Status and Intestinal Health of Weaned Piglets by Improving Their Intestinal Microbiota

Previous studies on the early interference of gut microbiota by Bacillus siamensis (B. siamensis) in weaned piglets are rarely reported, and the present trial is a preliminary study. This experiment was conducted to investigate the effects of B. siamensis supplementation on the growth performance, serum biochemistry, immune response, fecal short-chain fatty acids and microbiota of weaned piglets. Sixty weaned piglets were randomly divided into a control group (CON) and a B. siamensis group (BS), which were fed a basal diet and the basal diet supplemented with 5 × 1010 CFU B. siamensis per kg, respectively. Each group had 3 replicates and 10 piglets per replicate. The trial lasted for 28 days. The results showed that B. siamensis significantly increased the serum growth hormone (GH) and insulin-like growth factor (IGF) in piglets. Compared with the CON group, the levels of serum immunoglobulin and inflammatory factors in the BS group were significantly improved. In addition, the serum concentrations of zonulin and endotoxin (ET) in the BS group were lower. The dietary addition of B. siamensis significantly increased fecal short-chain fatty acid (SCFA) levels in piglets. Notably, B. siamensis improved the microbial composition by increasing beneficial genera, including Weissella, Lachnospiraceae_NK4A136_group and Bifidobacterium, and decreasing pathogenic genera, including Pantoea, Fusobacterium and Gemella, in piglet feces. Correlation analysis showed that the benefits of dietary B. siamensis supplementation were closely related to its improved microbial composition. In summary, the addition of B. siamensis can improve the immunity function, inflammatory response, gut permeability and SCFA levels of weaned piglets, which may be achieved through the improvement of their microbiota.

Causal relationship between gut microbiota and chronic renal failure: a two-sample Mendelian randomization study

Background

Observational studies and some experimental investigations have indicated that gut microbiota are closely associated with the incidence and progression of chronic renal failure. However, the causal relationship between gut microbiota and chronic renal failure remains unclear. The present study employs a two-sample Mendelian randomization approach to infer the causal relationship between gut microbiota and chronic renal failure at the genetic level. This research aims to determine whether there is a causal effect of gut microbiota on the risk of chronic renal failure, aiming to provide new evidence to support targeted gut therapy for the treatment of chronic renal failure.

Methods

Employing genome-wide association study (GWAS) data from the public MiBioGen and IEU OpenGWAS platform, a two-sample Mendelian randomization analysis was conducted. The causal relationship between gut microbiota and chronic renal failure was inferred using five different methods: Inverse Variance Weighted, MR-Egger, Weighted Median, Simple Mode, and Weighted Mode. The study incorporated sensitivity analyses that encompassed evaluations for pleiotropy and heterogeneity. Subsequently, the results of the Mendelian randomization analysis underwent a stringent correction for multiple testing, employing the False Discovery Rate method to enhance the validity of our findings.

Results

According to the results from the Inverse Variance Weighted method, seven bacterial genera show a significant association with the outcome variable chronic renal failure. Of these, Ruminococcus (gauvreauii group) (OR = 0.82, 95% CI = 0.71-0.94, p = 0.004) may act as a protective factor against chronic renal failure, while the genera Escherichia-Shigella (OR = 1.22, 95% CI = 1.08-1.38, p = 0.001), Lactococcus (OR = 1.1, 95% CI = 1.02-1.19, p = 0.013), Odoribacter (OR = 1.23, 95% CI = 1.03-1.49, p = 0.026), Enterorhabdus (OR = 1.14, 95% CI = 1.00-1.29, p = 0.047), Eubacterium (eligens group) (OR = 1.18, 95% CI = 1.02-1.37, p = 0.024), and Howardella (OR = 1.18, 95% CI = 1.09-1.28, p < 0.001) may be risk factors for chronic renal failure. However, after correction for multiple comparisons using False Discovery Rate, only the associations with Escherichia-Shigella and Howardella remain significant, indicating that the other genera have suggestive associations. Sensitivity analyses did not reveal any pleiotropy or heterogeneity.

Conclusion

Our two-sample Mendelian randomization study suggests that the genera Escherichia-Shigella and Howardella are risk factors for chronic renal failure, and they may serve as potential targets for future therapeutic interventions. However, the exact mechanisms of action are not yet clear, necessitating further research to elucidate their precise roles fully.

Oral microbiome characteristics in patients with pediatric solid tumor

Background

Pediatric solid tumor, the abnormal proliferation of solid tissues in children resulting in the formation of tumors, represent a prevailing malignant ailment among the younger population. Extensive literature highlights the inseparable association linking oral microbiome and adult tumors, but due to differences in age of onset, characteristics of onset, etc., there are many differences between Pediatric solid tumors and adult tumors, and therefore, studying the relationship between Pediatric solid tumor and the oral microbiota is also essential.

Methods

To unravel the distinct characteristics of the oral microbiota within Pediatric solid tumor patients, 43 saliva samples, encompassing 23 Pediatric solid tumor patients and 20 healthy controls, were diligently procured. A meticulous screening process ensued, and conducted microbial MiSeq sequencing after screening.

Results

We documented the oral microbiome attributes among pediatric diagnosed with solid tumors (PST), and meanwhile, we observed a significant trend of decreased oral microbiota diversity in the pediatric solid tumor group. There were notable disparities in microbial communities observed between the two groups, 18 genera including Veillonellaceae, Firmicutes unclassified, Coriobacteriia, Atopobiaceae, Negativicutes, were significantly enriched in PST patients, while 29 genera, including Gammaproteobacteria, Proteobacteria, Burkholderiales, Neisseriaceae, were dominant in the HCs group. It was found that PST group had 16 gene functions, including Amino acid metabolism, Cysteine and methionine metabolism, Photosynthesis antenna proteins, Arginine and proline metabolism, and Aminoacyl tRNA biosynthesi, were significantly dominant, while 29 gene functions that prevailed in HCs.

Conclusion

This study characterized the oral microbiota of Pediatric solid tumor patients for the first time, and importantly, targeted biomarkers of oral microbiota may serve as powerful and non-invasive diagnostic tools for pediatric solid tumor patients.

Beyond the Basics: Unraveling the Complexity of Coronary Artery Calcification

Coronary artery calcification (CAC) is mainly associated with coronary atherosclerosis, which is an indicator of coronary artery disease (CAD). CAC refers to the accumulation of calcium phosphate deposits, classified as micro- or macrocalcifications, that lead to the hardening and narrowing of the coronary arteries. CAC is a strong predictor of future cardiovascular events, such as myocardial infarction and sudden death. Our narrative review focuses on the pathophysiology of CAC, exploring its link to plaque vulnerability, genetic factors, and how race and sex can affect the condition. We also examined the connection between the gut microbiome and CAC, and the impact of genetic variants on the cellular processes involved in vascular calcification and atherogenesis. We aimed to thoroughly analyze the existing literature to improve our understanding of CAC and its potential clinical and therapeutic implications.

Akkermansia muciniphila attenuated lipopolysaccharide-induced acute lung injury by modulating the gut microbiota and SCFAs in mice

Gut microbiota are closely related to lipopolysaccharide (LPS)-induced acute lung injury (ALI). Akkermansia muciniphila (A. muciniphila) maintains the intestinal barrier function and regulates the balance of reduced glutathione/oxidized glutathione. However, it may be useful as a treatment strategy for LPS-induced lung injury. Our study aimed to explore whether A. muciniphila could improve lung injury by affecting the gut microbiota. The administration of A. muciniphila effectively attenuated lung injury tissue damage and significantly decreased the oxidative stress and inflammatory reaction induced by LPS, with lower levels of myeloperoxidase (MDA), enhanced superoxide dismutase (SOD) activity, decreased pro-inflammatory cytokine levels, and reduced macrophage and neutrophil infiltration. Moreover, A. muciniphila maintained the intestinal barrier function, reshaped the disordered microbial community, and promoted the secretion of short-chain fatty acids (SCFAs). A. muciniphila significantly downregulated the expression of TLR2, MyD88 and NF-kappa B (P < 0.05). Butyrate supplementation demonstrated a significant improvement in the inflammatory response (P < 0.05) and mitigation of histopathological damage in mice with ALI, thereby restoring the intestinal butyric acid concentration. In conclusion, our findings indicate that A. muciniphila inhibits the accumulation of inflammatory cytokines and attenuates the activation of the TLR2/Myd88/NF-κB pathway due to exerting anti-inflammatory effects through butyrate. This study provides an experimental foundation for the potential application of A. muciniphila and butyrate in the prevention and treatment of ALI.