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Clinical Nutrition Research Jul 2021Recently several studies have attempted to investigate the association between vitamin D and microbiota. However, studies have reported inconsistent results. This... (Review)
Review
Recently several studies have attempted to investigate the association between vitamin D and microbiota. However, studies have reported inconsistent results. This narrative review aimed to investigate the potential association between vitamin D and microbiota population in the gut by pooling together the results from observational studies and clinical trials. We considered animal and human studies in this field. Several studies have shown the correlation of vitamin D deficiency with microbiota. Furthermore, interventional studies were emerging that vitamin D change the microbiota composition in which leads to an increase in beneficial bacteria, such as , , , and while decreases in . Vitamin D could change the microbiota toward decreasing in and increasing in . At genera level, vitamin D may connect to some genera of family (e.g., , , , and ). It seems that adequate level of vitamin D is an important factor in improving the composition of the gut microbiota. More studies are needed to confirm possible underling mechanisms.
PubMed: 34386438
DOI: 10.7762/cnr.2021.10.3.181 -
Digestion 2023Fluoropyrimidines (FPs) are key drugs in many chemotherapy regimens; however, recipients are often prone to diarrhea due to gastrointestinal toxicity. Disruption of the... (Observational Study)
Observational Study
BACKGROUND AND AIM
Fluoropyrimidines (FPs) are key drugs in many chemotherapy regimens; however, recipients are often prone to diarrhea due to gastrointestinal toxicity. Disruption of the intestinal epithelial barrier function by FPs leads to dysbiosis, which may exacerbate intestinal epithelial cell damage as a secondary effect and trigger diarrhea. However, despite studies on chemotherapy-induced changes in the intestinal microbiome of humans, the relationship between dysbiosis and diarrhea is unclear. In this study, we aimed to investigate the relationship between chemotherapy-induced diarrhea and the intestinal microbiome.
METHODS
We conducted a single-center prospective observational study. Twenty-three patients who received chemotherapy, including FPs as first-line chemotherapy for colorectal cancer, were included. Stool samples were collected before the start of chemotherapy and after one cycle of treatment to analyze intestinal microbiome composition and perform PICRUSt predictive metagenomic analysis.
RESULTS
Gastrointestinal toxicity was observed in 7 of 23 patients (30.4%), diarrhea was observed in 4 (17.4%), and nausea and anorexia were observed in 3 (13.0%). In 19 patients treated with oral FPs, the α diversity of the microbial community decreased significantly following chemotherapy only in the diarrheal group. At the phylum level, the diarrheal group showed a significant decrease in the abundance of Firmicutes and a significant increase in the abundance of Bacteroidetes with chemotherapy (p = 0.013 and 0.011, respectively). In the same groups, at the genus level, Bifidobacterium abundance was significantly decreased (p = 0.019). In contrast, in the non-diarrheal group, Actinobacteria abundance increased significantly with chemotherapy at the phylum level (p = 0.011). Further, Bifidobacterium, Fusicatenibacter, and Dorea abundance significantly increased at the genus level (p = 0.006, 0.019, and 0.011, respectively). The PICRUSt predictive metagenomic analysis revealed that chemotherapy caused significant differences in membrane transport in KEGG pathway level 2 and in 8 KEGG pathway level 3, including transporters and oxidative phosphorylation in the diarrhea group.
CONCLUSION
Organic-acid-producing bacteria seem to be involved in diarrhea associated with chemotherapy, including FPs.
Topics: Humans; Gastrointestinal Microbiome; Dysbiosis; Diarrhea; Bacteria; Antineoplastic Agents; RNA, Ribosomal, 16S
PubMed: 37231829
DOI: 10.1159/000528282 -
The Journal of Nutrition Jan 2023Animal and small-cohort human studies have shown that tea consumption affects the gut microbiome, but evidence from large cohort studies is lacking.
BACKGROUND
Animal and small-cohort human studies have shown that tea consumption affects the gut microbiome, but evidence from large cohort studies is lacking.
OBJECTIVES
We examined associations between tea consumption and gut microbiome composition among older Chinese adults.
METHODS
The study included 1179 men and 1078 women from the Shanghai Men's and Women's Health Studies, who reported tea drinking status, type, amount, and duration at baseline and follow-up surveys (1996-2017) and were free of cancer, cardiovascular disease, and diabetes at stool collection (2015-2018). Fecal microbiome was profiled using 16S rRNA sequencing. Associations of tea variables with microbiome diversity and taxa abundance were evaluated using linear or negative binomial hurdle models after adjusting for sociodemographics, lifestyle, and hypertension status.
RESULTS
Mean age at stool collection was 67.2 ± 9.0 y in men and 69.6 ± 8.5 y in women. Tea drinking was not associated with microbiome ɑ-diversity in men or women; however, all tea variables were associated with β-diversity in men (P < 0.001). Significant associations with taxa abundance were also observed mostly in men. Current tea drinking, mainly green tea drinking, was associated with increase in orders Synergistales and RF39 in men (β = 0.30 to 0.42, all P ≤ 0.10) but not in women (P = 0.01). Also, increase in families Coriobacteriaceae, Odoribacteraceae, genera Collinsella, Odoribacter, and species Collinsella aerofaciens, Coprococcus catus, and Dorea formicigenerans were observed among men who drank >3.3 cups (781 mL)/d compared to that of nondrinkers (all P <0.10). The increased Coprococcus catus related to tea drinking was more evident among men without hypertension and inversely associated with the prevalence of hypertension (OR: 0.90; 95% CI: 0.84, 0.97; P = 0.03).
CONCLUSIONS
Tea consumption may affect gut microbiome β-diversity and abundance of some bacteria, which may contribute to reduced hypertension risk in Chinese men. Future studies should examine the sex-specific tea-gut microbiome associations and how certain bacteria may mediate the health benefits of tea.
Topics: Male; Humans; Adult; Female; Middle Aged; Aged; Gastrointestinal Microbiome; East Asian People; RNA, Ribosomal, 16S; Prospective Studies; China; Tea; Hypertension
PubMed: 36913464
DOI: 10.1016/j.tjnut.2022.12.002 -
Frontiers in Microbiology 2023Recent studies have suggested that the composition of gut microbiota (GM) may change after intracerebral hemorrhage. However, the causal inference of GM and hemorrhagic...
BACKGROUND
Recent studies have suggested that the composition of gut microbiota (GM) may change after intracerebral hemorrhage. However, the causal inference of GM and hemorrhagic stroke is unknown. Mendelian Randomization (MR) is an effective research method that removes confounding factors and investigates the causal relationship between exposure and outcome. This study intends to explore the causal relationship between GM and hemorrhagic stroke with the help of MR.
METHODS
Univariable and multivariable MR analyses were performed using summary statistics of the GM ( = 18,340) in the MiBioGen consortium vs. the FinnGen consortium R9 summary statistics (intracerebral hemorrhage, subarachnoid hemorrhage, and nontraumatic intracranial hemorrhage). Causal associations between gut microbiota and hemorrhagic stroke were analyzed using inverse variance weighted, MR-Egger regression, weighted median, weighted mode, simple mode, and MR-PRESSO. Cochran's statistic, MR-Egger regression, and leave-one-out analysis were used to test for multiplicity and heterogeneity of instrumental variables. Separate reverse MR analyses were performed for microbiota found to be causally associated with hemorrhagic stroke in the forward MR analysis. Also, multivariate MR analyses were conducted after incorporating common confounders.
RESULTS
Based on the results of univariable and multivariate MR analyses, (OR, 0.80; 95%CI, 0.66-0.97; = 0.025) had a protective effect against hemorrhagic stroke, while (OR, 0.81; 95%CI, 0.67-0.99; = 0.039) had a potential protective effect. Furthermore, (OR, 1.77; 95%CI, 1.27-2.46; = 0.001), (OR, 1.24; 95%CI, 1.05-1.48; = 0.013) and (OR, 1.28; 95%CI, 1.01-1.62; = 0.041) acted as potential risk factors for hemorrhagic stroke. The abundance of (β, 0.05; 95%CI, 0.002 ~ 0.101; = 0.041) may increase, and that of (β, -0.072; 95%CI, -0.137 ~ -0.007; = 0.030) decreased after hemorrhagic stroke according to the results of reverse MR analysis. No significant pleiotropy or heterogeneity was detected in any of the MR analyses.
CONCLUSION
There is a significant causal relationship between GM and hemorrhagic stroke. The prevention, monitoring, and treatment of hemorrhagic stroke through GM represent a promising avenue and contribute to a deeper understanding of the mechanisms underlying hemorrhagic stroke.
PubMed: 38188561
DOI: 10.3389/fmicb.2023.1290909 -
Frontiers in Microbiology 2024The objective of this study is to investigate the causal relationship between gut microbiota and juvenile idiopathic arthritis, and to identify and quantify the...
OBJECTIVE
The objective of this study is to investigate the causal relationship between gut microbiota and juvenile idiopathic arthritis, and to identify and quantify the potential role of plasma metabolites as mediators.
METHODS
Using summary-level data from genome-wide association studies, a two-sample Mendelian randomization was conducted involving 131 gut microbiota genus, 1,400 plasma metabolites, and juvenile idiopathic arthritis. Additionally, a two-step approach was employed to quantify the proportion of the effect of gut microbiota on juvenile idiopathic arthritis mediated by plasma metabolites. Effect estimation primarily utilized Inverse Variance Weighting, with further validation using Bayesian weighted Mendelian randomization.
RESULTS
In our MR analysis, a positive correlation was observed between and the risk of juvenile idiopathic arthritis, while showed a negative correlation with juvenile idiopathic arthritis risk. Mediation analysis indicated that Furaneol sulfate levels acted as a mediator between and juvenile idiopathic arthritis, with an indirect effect proportion of 19.94, 95% CI [8.86-31.03%].
CONCLUSION
Our study confirms a causal relationship between specific microbial genus and juvenile idiopathic arthritis, and computes the proportion of the effect mediated by plasma metabolites, offering novel insights for clinical interventions in juvenile idiopathic arthritis.
PubMed: 38605717
DOI: 10.3389/fmicb.2024.1363776 -
Nutrients Jul 2023Western diet (WD) intake, aging, and inactivation of farnesoid X receptor (FXR) are risk factors for metabolic and chronic inflammation-related health issues ranging...
Western diet (WD) intake, aging, and inactivation of farnesoid X receptor (FXR) are risk factors for metabolic and chronic inflammation-related health issues ranging from metabolic dysfunction-associated steatotic liver disease (MASLD) to dementia. The progression of MASLD can be escalated when those risks are combined. Inactivation of FXR, the receptor for bile acid (BA), is cancer prone in both humans and mice. The current study used multi-omics including hepatic transcripts, liver, serum, and urine metabolites, hepatic BAs, as well as gut microbiota from mouse models to classify those risks using machine learning. A linear support vector machine with -fold cross-validation was used for classification and feature selection. We have identified that increased urine sucrose alone achieved 91% accuracy in predicting WD intake. Hepatic lithocholic acid and serum pyruvate had 100% and 95% accuracy, respectively, to classify age. Urine metabolites (decreased creatinine and taurine as well as increased succinate) or increased gut bacteria (, , and ) could predict FXR deactivation with greater than 90% accuracy. Human disease relevance is partly revealed using the metabolite-disease interaction network. Transcriptomics data were also compared with the human liver disease datasets. WD-reduced hepatic (cytochrome P450 family 39 subfamily a member 1) and increased (GRAM domain containing 1B) were also changed in human liver cancer and metabolic liver disease, respectively. Together, our data contribute to the identification of noninvasive biomarkers within the gut-liver axis to predict metabolic status.
Topics: Mice; Humans; Animals; Liver; Fatty Liver; Liver Neoplasms; Inflammation; Biomarkers; Bile Acids and Salts; Mice, Inbred C57BL
PubMed: 37571345
DOI: 10.3390/nu15153406 -
Journal of Microbiology and... Dec 2023Biochemical gut metabolism of dietary bioactive compounds is of great significance in elucidating health-related issues at the molecular level. In this study, a human...
Biochemical gut metabolism of dietary bioactive compounds is of great significance in elucidating health-related issues at the molecular level. In this study, a human gut bacterium cleaving C-C glycosidic bond was screened from puerarin conversion to daidzein, and a new, gram-positive -glycoside-deglycosylating strain, sp. MRG-IFC3, was isolated from human fecal sample under anaerobic conditions. Though MRG-IFC3 biotransformed isoflavone -glycoside, it could not metabolize other -glycosides, such as vitexin, bergenin, and aloin. As evident from the production of the corresponding aglycons from various 7--glucosides, MRG-IFC3 strain also showed 7--glycoside cleavage activity; however, flavone 3--glucoside icariside II was not metabolized. In addition, for mechanism study, -glycosyl bond cleavage of puerarin by MRG-IFC3 strain was performed in DO GAM medium. The complete deuterium enrichment on C-8 position of daidzein was confirmed by H NMR spectroscopy, and the result clearly proved for the first time that daidzein is produced from puerarin. Two possible reaction intermediates, the quinoids and 8-dehydrodaidzein anion, were proposed for the production of daidzein-8d. These results will provide the basis for the mechanism study of stable -glycosidic bond cleavage at the molecular level.
Topics: Humans; Bacteria; Glycosides; Isoflavones; Glucosides; Feces
PubMed: 37789701
DOI: 10.4014/jmb.2308.08021 -
Clinica Chimica Acta; International... Apr 2015Thimerosal (or Thiomersal) is a trade name for an organomercurial compound (sodium ethyl-mercury (Hg) thiosalicylate) that is 49.55% Hg by weight, which rapidly... (Review)
Review
INTRODUCTION
Thimerosal (or Thiomersal) is a trade name for an organomercurial compound (sodium ethyl-mercury (Hg) thiosalicylate) that is 49.55% Hg by weight, which rapidly decomposes in aqueous saline solutions into ethyl-Hg hydroxide and ethyl-Hg chloride. Developed in 1927, it has been and is still being used as a preservative in some cosmetics, topical pharmaceuticals, and biological drug products, including vaccines. Concerns have been voiced about its use because it is toxic to human cells. Although it is banned in several countries, it continues to be added to some vaccines in the United States and many vaccines in the developing world.
DISCUSSION
This critical review focuses on the clinical, epidemiological, and biochemical studies of adverse effects from Thimerosal in developing humans. This review will include research that examines fetal, infant, and childhood death; birth defects; neurodevelopmental testing deficits in children; and neurodevelopmental disorders (attention deficit/hyperactivity disorder, autism spectrum disorder, tic disorder, and specific developmental delays). The review will also look at the research that examined the outcomes of acute accidental ethyl-Hg poisoning in humans. The studies that examine the underlying biochemical insights into the neuronal cellular damage will also be explored.
CONCLUSION
The culmination of the research that examines the effects of Thimerosal in humans indicates that it is a poison at minute levels with a plethora of deleterious consequences, even at the levels currently administered in vaccines.
Topics: Growth and Development; Humans; Thimerosal
PubMed: 25708367
DOI: 10.1016/j.cca.2015.02.030 -
Microbiology Spectrum Jun 2023Over the past decade, the role of the gut microbiota in many disease states has gained a great deal of attention. Mounting evidence from case-control and observational... (Meta-Analysis)
Meta-Analysis
Over the past decade, the role of the gut microbiota in many disease states has gained a great deal of attention. Mounting evidence from case-control and observational studies has linked changes in the gut microbiota to the pathophysiology of osteoporosis (OP). Nonetheless, the results of these studies contain discrepancies, leaving the literature without a consensus on osteoporosis-associated microbial signatures. Here, we conducted a comprehensive meta-analysis combining and reexamining five publicly available 16S rRNA partial sequence data sets to identify gut bacteria consistently associated with osteoporosis across different cohorts. After adjusting for the batch effect associated with technical variation and heterogeneity of studies, we observed a significant shift in the microbiota composition in the osteoporosis group. An increase in the relative abundance of opportunistic pathogens , , and was observed in the OP group. Moreover, short-chain-fatty-acid (SCFA) producers, including members of the genera , , , , XIV, and , were depleted in the OP group relative to the healthy control (HC) group. Lactic acid-producing bacteria, including , were significantly increased in the OP group. The random forest algorithm further confirmed that these bacteria differentiate the two groups. Furthermore, functional prediction revealed depletion of the SCFA biosynthesis pathway (glycolysis, tricarboxylic acid [TCA] cycle, and Wood-Ljungdahl pathway) and amino acid biosynthesis pathway (methionine, histidine, and arginine) in the OP group relative to the HC group. This study uncovered OP-associated compositional and functional microbial alterations, providing robust insight into OP pathogenesis and aiding the possible development of a therapeutic intervention to manage the disease. Osteoporosis is the most common metabolic bone disease associated with aging. Mounting evidence has linked changes in the gut microbiota to the pathophysiology of osteoporosis. However, which microbes are associated with dysbiosis and their impact on bone density and inflammation remain largely unknown due to inconsistent results in the literature. Here, we present a meta-analysis with a standard workflow, robust statistical approaches, and machine learning algorithms to identify notable microbial compositional changes influencing osteoporosis.
Topics: Humans; Feces; RNA, Ribosomal, 16S; Bacteria; Gastrointestinal Microbiome; Lactobacillales; Osteoporosis
PubMed: 37042756
DOI: 10.1128/spectrum.00322-23 -
Frontiers in Endocrinology 2023The risk of developing micro- and macrovascular complications is higher for individuals with type 1 diabetes (T1D). Numerous studies have indicated variations in gut...
OBJECTIVE
The risk of developing micro- and macrovascular complications is higher for individuals with type 1 diabetes (T1D). Numerous studies have indicated variations in gut microbial composition between healthy individuals and those with T1D. These changes in the gut ecosystem may lead to inflammation, modifications in intestinal permeability, and alterations in metabolites. Such effects can collectively impact the metabolic regulation system, thereby influencing blood glucose control. This review aims to explore the relationship between the gut microbiome, inflammation, and blood glucose parameters in patients with T1D.
METHODS
Google Scholar, PubMed, and Web of Science were systematically searched from 2003 to 2023 using the following keywords: "gut microbiota," "gut microbiome," "bacteria," "T1D," "type 1 diabetes," "autoimmune diabetes," "glycemic control," "glucose control," "HbA1c," "inflammation," "inflammatory," and "cytokine." The examination has shown 18,680 articles with relevant keywords. After the exclusion of irrelevant articles, seven observational papers showed a distinct gut microbial signature in T1D patients.
RESULTS
This review shows that, in T1D patients, HbA1c level was negatively correlated with abundance of , , and and positively correlated with abundance of , , , and . Instead, was negatively correlated with fasting blood glucose. In addition, there was a positive correlation between and time in range. Furthermore, a positive correlation between inflammatory parameters and gut dysbiosis was revealed in T1D patients.
CONCLUSION
We draw the conclusion that the gut microbiome profiles of T1D patients and healthy controls differ. Patients with T1D may experience leaky gut, bacterial translocation, inflammation, and poor glucose management due to microbiome dysbiosis. Direct manipulation of the gut microbiome in humans and its effects on gut permeability and glycemic control, however, have not been thoroughly investigated. Future research should therefore thoroughly examine other potential pathophysiological mechanisms in larger studies.
Topics: Humans; Blood Glucose; Diabetes Mellitus, Type 1; Dysbiosis; Gastrointestinal Microbiome; Glycated Hemoglobin; Glycemic Control; Inflammation
PubMed: 38034007
DOI: 10.3389/fendo.2023.1265696