Gut microbiome and metabolome profiling in Framingham heart study reveals cholesterol-metabolizing bacteria

Administration of Alistipes indistinctus prevented the progression from nonalcoholic fatty liver disease to nonalcoholic steatohepatitis by enhancing the gut barrier and increasing Lactobacillus spp

Metabolic-associated fatty liver disease (MAFLD) is an important public health problem, and the gut microbiota has become a new treatment target for MAFLD. Previously, A. indistinctus, a core gut bacterium, was shown to potentially contribute to the prevention of MAFLD. However, the effect and mechanism of A. indistinctus on MAFLD are still unclear and need to be investigated. This study primarily evaluated whether A. indistinctus can improve gut microbiota disorders and prevent the progression from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH) in mice fed a high-fat diet (HFD). First, we observed that A. indistinctus significantly improved lipid metabolism disorders and reduced hepatic inflammation induced by HFD consumption in mice. We found that A. indistinctus improved gut barrier function and inhibited the LPS/TLR4/NF-κB pathway, thereby reducing hepatic inflammation. Moreover, 16S rRNA V3-V4 analyses revealed that A. indistinctus could significantly change the structure of the gut microbiota and increase the abundance of L. johnsonii by promoting its growth. Finally, we showed that L. johnsonii administration significantly improved lipid metabolism disorders and reduced hepatic lipid accumulation induced by HFD consumption in mice. In summary, A. indistinctus administration significantly reduces hepatic inflammation by improving gut barrier function and improves lipid metabolism disorders by promoting the growth of L. johnsonii. Our research improves the understanding of the gut microbiota and provides a basis for future therapeutic use of A. indistinctus.

Pre-procedural TMAO as a predictor for recurrence of atrial fibrillation after catheter ablation

BACKGROUND

Numerous studies have demonstrated the significance of trimethylamine-N-oxide (TMAO) in the progression of atrial fibrillation (AF). However, the association between TMAO and AF recurrence (RAF) post-catheter ablation is not yet fully understood. This study aims to elucidate the predictive capability of pre-procedural TMAO levels in determining RAF following catheter ablation (CA).

METHODS

This study was conducted as a prospective, single-center observational study. Between June 2021 and June 2022, 152 patients from the Department of Cardiology at The Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University were enrolled. Baseline characteristics and serum TMAO levels were assessed for all participants. Patients with AF who underwent CA were monitored for recurrences of AF using electrocardiography (ECG) or 24-hour Holter monitoring during the follow-up period.

RESULTS

The study found that serum TMAO levels were significantly higher in persistent AF (PeAF) patients compared to those in sinus rhythm (SR) and paroxysmal AF (PaAF) patients (3.96 ± 1.69 vs. 1.81 ± 0.59, 3.02 ± 1.50 µM, P < 0.001 and P < 0.01, respectively). After a one-year follow-up, 29 (21.2%) AF patients experienced recurrence after CA. Multivariate Cox proportional hazards regression analysis revealed that pre-procedural serum TMAO was an independent predictor of recurrent AF (HR = 1.78, 95% CI = 1.43-2.21, P < 0.001). The receiver operating characteristic (ROC) curve analysis identified a cut-off value of 4.3µM for serum TMAO levels in predicting recurrent AF (area under the curve: 0.835, P < 0.001). The Kaplan-Meier plot demonstrated that patients with TMAO levels greater than 4.3µM had a significantly higher rate of recurrent AF (HR = 13.53, 95% CI = 6.19-29.56, P < 0.001).

CONCLUSION

Patients with AF exhibited elevated levels of circulating TMAO compared to patients with SR. The findings suggest a potential role of TMAO in the development of AF, with pre-procedural serum TMAO levels serving as a reliable predictor of recurrence of AF CA.

Drugs for dyslipidaemia: the legacy effect of the Scandinavian Simvastatin Survival Study (4S)

Since the discovery of statins and the Scandinavian Simvastatin Survival Study (4S) results three decades ago, remarkable advances have been made in the treatment of dyslipidaemia, a major risk factor for atherosclerotic cardiovascular disease. Safe and effective statins remain the cornerstone of therapeutic approach for this indication, including for children with genetic dyslipidaemia, and are one of the most widely prescribed drugs in the world. However, despite the affordability of generic statins, they remain underutilised worldwide. The use of ezetimibe to further decrease plasma LDL cholesterol and the targeting of other atherogenic lipoproteins, such as triglyceride-rich lipoproteins and lipoprotein(a), are likely to be required to further reduce atherosclerotic cardiovascular disease events. Drugs directed at these lipoproteins, including gene silencing and editing methods that durably suppress the production of proteins, such as PCSK9 and ANGPTL3, open novel therapeutic options to further reduce the development of atherosclerotic cardiovascular disease.

MaAsLin 3: Refining and extending generalized multivariable linear models for meta-omic association discovery

A key question in microbial community analysis is determining which microbial features are associated with community properties such as environmental or health phenotypes. This statistical task is impeded by characteristics of typical microbial community profiling technologies, including sparsity (which can be either technical or biological) and the compositionality imposed by most nucleotide sequencing approaches. Many models have been proposed that focus on how the relative abundance of a feature (e.g. taxon or pathway) relates to one or more covariates. Few of these, however, simultaneously control false discovery rates, achieve reasonable power, incorporate complex modeling terms such as random effects, and also permit assessment of prevalence (presence/absence) associations and absolute abundance associations (when appropriate measurements are available, e.g. qPCR or spike-ins). Here, we introduce MaAsLin 3 (Microbiome Multivariable Associations with Linear Models), a modeling framework that simultaneously identifies both abundance and prevalence relationships in microbiome studies with modern, potentially complex designs. MaAsLin 3 also newly accounts for compositionality with experimental (spike-ins and total microbial load estimation) or computational techniques, and it expands the space of biological hypotheses that can be tested with inference for new covariate types. On a variety of synthetic and real datasets, MaAsLin 3 outperformed current state-of-the-art differential abundance methods in testing and inferring associations from compositional data. When applied to the Inflammatory Bowel Disease Multi-omics Database, MaAsLin 3 corroborated many previously reported microbial associations with the inflammatory bowel diseases, but notably 77% of associations were with feature prevalence rather than abundance. In summary, MaAsLin 3 enables researchers to identify microbiome associations with higher accuracy and more specific association types, especially in complex datasets with multiple covariates and repeated measures.

Mendelian randomization analyses support causal relationships between gut microbiome and longevity

BACKGROUND

Gut microbiome plays a significant role in longevity, and dysbiosis is indeed one of the hallmarks of aging. However, the causal relationship between gut microbiota and human longevity or aging remains elusive.

METHODS

Our study assessed the causal relationships between gut microbiome and longevity using Mendelian Randomization (MR). Summary statistics for the gut microbiome were obtained from four genome-wide association study (GWAS) meta-analysis of the MiBioGen consortium (N = 18,340), Dutch Microbiome Project (N = 7738), German individuals (N = 8956), and Finland individuals (N = 5959). Summary statistics for Longevity were obtained from Five GWAS meta-analysis, including Human healthspan (N = 300,447), Longevity (N = 36,745), Lifespans (N = 1,012,240), Parental longevity (N = 389,166), and Frailty (one of the primary aging-linked physiological hallmarks, N = 175,226).

RESULTS

Our findings reveal several noteworthy associations, including a negative correlation between Bacteroides massiliensis and longevity, whereas the genus Subdoligranulum and Alistipes, as well as species Alistipes senegalensis and Alistipes shahii, exhibited positive associations with specific longevity traits. Moreover, the microbial pathway of coenzyme A biosynthesis I, pyruvate fermentation to acetate and lactate II, and pentose phosphate pathway exhibited positive associations with two or more traits linked to longevity. Conversely, the TCA cycle VIII (helicobacter) pathway consistently demonstrated a negative correlation with lifespan and parental longevity.

CONCLUSIONS

Our findings of this MR study indicated many significant associations between gut microbiome and longevity. These microbial taxa and pathways may potentially play a protective role in promoting longevity or have a suppressive effect on lifespan.

The role of the gut microbial metabolism of sterols and bile acids in human health

Sterols and bile acids are vital signaling molecules that play key roles in systemic functions, influencing the composition of the human gut microbiota, which maintains a symbiotic relationship with the host. Additionally, gut microbiota-encoded enzymes catalyze the conversion of sterols and bile acids into various metabolites, significantly enhancing their diversity and biological activities. In this review, we focus on the microbial transformations of sterols and bile acids in the gut, summarize the relevant bacteria, genes, and enzymes, and review the relationship between the sterols and bile acids metabolism of gut microbiota and human health. This review contributes to a deeper understanding of the crucial roles of sterols and bile acids metabolism by gut microbiota in human health, offering insights for further investigation into the interactions between gut microbiota and the host.

Evaluation of the growth performance, meat quality, and gut microbiota of broilers fed diets containing walnut green husk extract

This study was conducted to evaluate the effects of walnut green husk extract (WGHe) on the growth performance, meat quality, antioxidative status, gut morphology, and microbiota diversity of broilers. A total of 216 one-day-old broilers were divided into 4 groups, each consisting of 9 replicates (6 birds per replicate) as follows: 1) control group, basal diet; 2) antibiotic group, basal diet supplemented with enduracidin and colistin sulfate; 3) low-dose group, basal diet supplemented with 5.0 g/kg WGHe; and 4) high-dose group, basal diet supplemented with 10.0 g/kg WGHe. The results revealed that the percentage of abdominal fat decreased, and the ratio of the duodenal villus length to crypt depth (V/C), as well as the α-diversity of the ileal microbiota, increased with 10.0 g/kg WGHe supplementation (P < 0.05). The shear force of the breast muscle and plasma malondialdehyde (MDA) concentration decreased, whereas the plasma peroxidase (POD) activity, Trolox equivalent antioxidant capacity (TEAC), and jejunal villus length increased in response to WGHe supplementation (P < 0.05). Compared with the antibiotic diet, the addition of 5.0 g/kg WGHe resulted in a significant increase in the relative abundances of Candidatus Arthromitus, Eubacterium coprostanoligenes, and Ruminococcaceae UCG-014 (P < 0.01). Furthermore, the addition of 10.0 g/kg WGHe increased the relative abundances of Candidatus Arthromitus and Lachnoclostridium, whereas the relative abundance of unidentified Chloroplast decreased (P < 0.05). In conclusion, dietary supplementation with 10.0 g/kg WGHe is advantageous for intestinal health, meat quality, and antioxidant status in broilers, suggesting its potential as a functional additive in poultry production.

Plasma metabolites as mediators in the relationship between inflammation-related proteins and benign prostatic hyperplasia: insights from mendelian randomization

Benign prostatic hyperplasia (BPH) is a condition commonly observed in aging males. Inflammatory and metabolic factors are pivotal in the development and progression of BPH. The degree to which the effects of 91 inflammation-related proteins on BPH are mediated by 1400 plasma metabolites remains ambiguous. Our research analyzed the impact of these traits utilizing genetic evidence.Two-sample Mendelian randomization (MR) and multivariable MR (MVMR) were utilized in our study to infer the genetic causal effect of inflammation-related proteins on BPH, with metabolites serving as mediators. Increased levels of IL-2 were linked to a heightened incidence of BPH (β = 0.071, OR:1.074, 95% CI [1.002-1.152], p = 0.045), whereas lower concentrations of N6,N6-dimethyllysine were associated with decreased risk (β1=-0.127, p = 0.02; β2=-0.039, p = 0.008). The mediation effect was 0.005 (95% CI [0.0004, 0.012], OR: 1.005, 95% CI [1.000, 1.012]), accounting for 7.04% of the total effect. subsequently, we examined the phenotypic co-localization of the two pairings independently, revealing that the posterior probability of rs145516501 associated with IL-2 and BPH was 80.7%, whereas the posterior likelihood of rs4917820 linked to N6,N6-dimethyllysine levels and BPH was 95.9%. The research indicated that N6,N6-dimethyllysine levels seem to influence the causative relationship between IL-2 and BPH. These results elucidate the complex interplay between inflammation-related proteins and metabolism in the context of BPH, offering novel diagnostic and therapeutic avenues and enhancing our comprehension of the disease's etiology for prospective research.

Lactobacillus Eats Amyloid Plaque and Post-Biotically Attenuates Senescence Due to Repeat Expansion Disorder and Alzheimer's Disease

Patients with Alzheimer's disease and related dementia (ADRD) are faced with a formidable challenge of focal amyloid deposits and cerebral amyloid angiopathy (CAA). The treatment of amyloid deposits in ADRD by targeting only oxidative stress, inflammation and hyperlipidemia has not yielded significant positive clinical outcomes. The chronic high-fat diet (HFD), or gut dysbiosis, is one of the major contributors of ADRD in part by disrupted transport, epigenetic DNMT1 and the folate 1-carbon metabolism (FOCM) cycle, i.e., rhythmic methylation/de-methylation on DNA, an active part of epigenetic memory during genes turning off and on by the gene writer (DNMT1) and eraser (TET2/FTO) and the transsulfuration pathway by mitochondrial 3-mercaptopyruvate sulfur transferase (3MST)-producing H2S. The repeat CAG expansion and m6A disorder causes senescence and AD. We aim to target the paradigm-shift pathway of the gut-brain microbiome axis that selectively inhibits amyloid deposits and increases mitochondrial transsulfuration and H2S. We have observed an increase in DNMT1 and decreased FTO levels in the cortex of the brain of AD mice. Interestingly, we also observed that probiotic lactobacillus-producing post-biotic folate and lactone/ketone effectively prevented FOCM-associated gut dysbiosis and amyloid deposits. The s-adenosine-methionine (SAM) transporter (SLC25A) was increased by hyperhomocysteinemia (HHcy). Thus, we hypothesize that chronic gut dysbiosis induces SLC25A, the gene writer, and HHcy, and decreases the gene eraser, leading to a decrease in SLC7A and mitochondrial transsulfuration H2S production and bioenergetics. Lactobacillus engulfs lipids/cholesterol and a tri-directional post-biotic, folic acid (an antioxidant and inhibitor of beta amyloid deposits; reduces Hcy levels), and the lactate ketone body (fuel for mitochondria) producer increases SLC7A and H2S (an antioxidant, potent vasodilator and neurotransmitter gas) production and inhibits amyloid deposits. Therefore, it is important to discuss whether lactobacillus downregulates SLC25A and DNMT1 and upregulates TET2/FTO, inhibiting β-amyloid deposits by lowering homocysteine. It is also important to discuss whether lactobacillus upregulates SLC7A and inhibits β-amyloid deposits by increasing the mitochondrial transsulfuration of H2S production.

What defines a healthy gut microbiome?

The understanding that changes in microbiome composition can influence chronic human diseases and the efficiency of therapies has driven efforts to develop microbiota-centred therapies such as first and next generation probiotics, prebiotics and postbiotics, microbiota editing and faecal microbiota transplantation. Central to microbiome research is understanding how disease impacts microbiome composition and vice versa, yet there is a problematic issue with the term 'dysbiosis', which broadly links microbial imbalances to various chronic illnesses without precision or definition. Another significant issue in microbiome discussions is defining 'healthy individuals' to ascertain what characterises a healthy microbiome. This involves questioning who represents the healthiest segment of our population-whether it is those free from illnesses, athletes at peak performance, individuals living healthily through regular exercise and good nutrition or even elderly adults or centenarians who have been tested by time and achieved remarkable healthy longevity.This review advocates for delineating 'what defines a healthy microbiome?' by considering a broader range of factors related to human health and environmental influences on the microbiota. A healthy microbiome is undoubtedly linked to gut health. Nevertheless, it is very difficult to pinpoint a universally accepted definition of 'gut health' due to the complexities of measuring gut functionality besides the microbiota composition. We must take into account individual variabilities, the influence of diet, lifestyle, host and environmental factors. Moreover, the challenge in distinguishing causation from correlation between gut microbiome and overall health is presented.The review also highlights the resource-heavy nature of comprehensive gut health assessments, which hinders their practicality and broad application. Finally, we call for continued research and a nuanced approach to better understand the intricate and evolving concept of gut health, emphasising the need for more precise and inclusive definitions and methodologies in studying the microbiome.

Association of lipid-lowering drugs with gut microbiota: A Mendelian randomization study

BACKGROUND

The gut microbiota can be influenced by lipid metabolism. We aimed to evaluate the impact of lipid-lowering medications, such as proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, Niemann-Pick C1-Like 1 protein (NPC1L1) inhibitors, and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) inhibitors, on gut microbiota through drug target Mendelian randomization (MR) investigation.

METHODS

We used genetic variants that were associated with low-density lipoprotein cholesterol (LDL-C) in genome-wide association studies and located within or near drug target genes as proxies for lipid-lowering drug exposure. In addition, expression trait loci in drug target genes were used as complementary genetic tools. We used effect estimates calculated using inverse variance weighted MR (IVW-MR) and summary data-based MR (SMR). Multiple sensitivity analyses were performed.

RESULTS

Genetic proxies for lipid-lowering drugs broadly affected the abundance of gut microbiota. High expression of NPC1L1 was significantly associated with an increase in the genus Eggerthella (β = 1.357, SE = 0.337, P = 5.615 × 10-5). An HMGCR-mediated increase in LDL-C was significantly associated with the order Pasteurellales (β = 0.489, SE = 0.123, P = 6.955 × 10-5) and the genus Haemophilus (β = 0.491, SE = 0.125, P = 8.379 × 10-5), whereas a PCSK9-mediated increase in LDL-C was associated with the genus Terrisporobacter (β = 0.666, SE = 0.127, P = 1.649 × 10-5). No pleiotropy was detected.

CONCLUSIONS

This drug target MR highlighted the potential interventional effects of lipid-lowering drugs on the gut microbiota and separately revealed the possible effects of different types of lipid-lowering drugs on specific gut microbiota.

Widely Targeted Lipidomics and Microbiomics Perspectives Reveal the Mechanism of Auricularia auricula Polysaccharide's Effect of Regulating Glucolipid Metabolism in High-Fat-Diet Mice

The role of Auricularia auricula polysaccharide (AP) in the regulation of glycolipid metabolism was investigated using a high-fat-diet-induced hyperlipidemic mouse model. In a further step, its potential mechanism of action was investigated using microbiome analysis and widely targeted lipidomics. Compared to high-fat mice, dietary AP supplementation reduced body weight by 13.44%, liver index by 21.30%, epididymal fat index by 50.68%, fasting blood glucose (FBG) by 14.27%, serum total cholesterol (TC) by 20.30%, serum total triglycerides (TGs) by 23.81%, liver non-esterified fatty acid (NEFA) by 20.83%, liver TGs by 20.00%, and liver malondialdehyde (MDA) by 21.05%, and increased liver glutathione oxidase (GSH-PX) activity by 52.24%, total fecal bile acid (TBA) by 46.21%, and fecal TG by 27.16%, which significantly regulated glucose and lipid metabolism. Microbiome analysis showed that AP significantly downregulated the abundance of the Desulfobacterota phylum, as well as the genii Desulfovibrio, Bilophila, and Oscillbacter in the cecum of hyperlipidemic mice, which are positively correlated with high lipid indexes, while it upregulated the abundance of the families Eubacterium_coprostanoligenes_group and Ruminococcaceae, as well as the genii Eubacterum_xylanophilum_group, Lachnospiraceae_NK4A136_group, Eubacterium_siraeum_group, and Parasutterella, which were negatively correlated with high lipid indexes. In addition, AP promoted the formation of SCFAs by 119.38%. Widely targeted lipidomics analysis showed that AP intervention regulated 44 biomarkers in metabolic pathways such as sphingolipid metabolism and the AGE-RAGE signaling pathway in the hyperlipidemic mice (of which 15 metabolites such as unsaturated fatty acids, phosphatidylserine, and phosphatidylethanolamine were upregulated, and 29 metabolites such as phosphatidylcholine, ceramide, carnitine, and phosphatidylinositol were downregulated), thereby correcting glucose and lipid metabolism disorders.

AGFG1 increases cholesterol biosynthesis by disrupting intracellular cholesterol homeostasis to promote PDAC progression

PURPOSE

Cholesterol metabolism reprograming has been acknowledged as a novel feature of cancers. Pancreatic ductal adenocarcinoma (PDAC) is a cancer with a high demand of cholesterol for rapid growth. The underlying mechanism of how cholesterol metabolism homestasis are disturbed in PDAC is explored.

EXPERIMENTAL DESIGN

The relevance between PDAC and cholesterol was confirmed in TCGA database. The expression and clinical association were discovered in TCGA and GEO datasets. Knockdown and overexpression of AGFG1 was adopted to perform function studies. RNA sequencing, cholesterol detection, transmission electron microscope, co-immunoprecipitation, and immunofluorescence et al. were utilized to reveal the underlying mechanism.

RESULTS

AGFG1 was identified as one gene positively correlated with cholesterol metabolism in PDAC as revealed by bioinformatics analysis. AGFG1 expression was then found associated with poor prognosis in PDAC. AGFG1 knockdown led to decreased proliferation of tumor cells both in vitro and in vivo. By RNA sequencing, we found AGFG1 upregulated expression leads to enhanced intracellular cholesterol biosynthesis. AGFG1 knockdown suppressed cholesterol biosynthesis and an accumulation of cholesterol in the ER. Mechanistically, we confirmed that AGFG1 interacted with CAV1 to relocate cholesterol for the proceeding of cholesterol biosynthesis, therefore causing disorders in intracellular cholesterol metabolism.

CONCLUSIONS

Our study demonstrates the tumor-promoting role of AGFG1 by disturbing cholesterol metabolism homestasis in PDAC. Our study has present a new perspective on cancer therapeutic approach based on cholerstrol metabolism in PDAC.

The Effects of Caloric Restriction and Clinical Psychological Intervention on the Interplay of Gut Microbial Composition and Stress in Women

Both mental and metabolic disorders are steadily becoming more prevalent, increasing interest in non-pharmacological lifestyle interventions targeting both types of disorders. However, the combined effect of diet and psychological interventions on the gut microbiome and mental health outcomes remains underexplored. Thus, in this study, we randomized 41 women into two caloric restriction (CR) dietary groups, namely very-low-calorie diet (VLCD) and F.X. Mayr diet (FXM). The patients were then further randomized to either receive clinical psychological intervention (CPI) or no CPI. Blood and fecal samples were collected before and after two weeks of CR. Psychometric outcomes were assessed using the Perceived Stress Scale (PSS), Brief Symptom Index (BSI), and Burnout Dimension Inventory (BODI). Stool samples underwent 16S-rRNA sequencing. Upon two weeks of CR, α-diversity decreased overall and longitudinal PERMANOVA models revealed significant shifts in β-diversity according to diet, CPI, age, and body-mass-index. Furthermore, Agathobacter, Fusicatenibacter, and Subdoligranulum decreased in abundance. However, the Oscillibacter genus was enriched solely in FXM. CPI had a negligible effect on the microbiome. Dimension reduction models revealed clusters of taxa which distinctly associated with psychometric outcomes. Members of the Oscillospiraceae family were linked to favorable psychometric outcomes after two weeks of CR. Despite α-diversity reductions after CR, enrichment of Oscillospiraceae spp., solely seen in FXM, correlated with improved psychometric outcomes. This study suggests a promising direction for future interventions targeting mental health through gut microbial modulation.

Western diets and chronic diseases

'Westernization', which incorporates industrial, cultural and dietary trends, has paralleled the rise of noncommunicable diseases across the globe. Today, the Western-style diet emerges as a key stimulus for gut microbial vulnerability, chronic inflammation and chronic diseases, affecting mainly the cardiovascular system, systemic metabolism and the gut. Here we review the diet of modern times and evaluate the threat it poses for human health by summarizing recent epidemiological, translational and clinical studies. We discuss the links between diet and disease in the context of obesity and type 2 diabetes, cardiovascular diseases, gut and liver diseases and solid malignancies. We collectively interpret the evidence and its limitations and discuss future challenges and strategies to overcome these. We argue that healthcare professionals and societies must react today to the detrimental effects of the Western diet to bring about sustainable change and improved outcomes in the future.

Evaluating the Effects of Corn Flour Product Consumption on Cardiometabolic Outcomes and the Gut Microbiota in Adults with Elevated Cholesterol: A Randomized Crossover

BACKGROUND

Consumption of whole grains is associated with a reduction in chronic diseases and offers benefits for cardiovascular health and metabolic regulation. The relationship between whole-grain corn and corn bran with the gut microbiota (GM) remains an area of growing interest, particularly regarding their influence on cardiometabolic health.

OBJECTIVES

To investigate the effects of different corn flours on cardiometabolic outcomes and GM changes in adults with elevated low-density lipoprotein cholesterol (LDL cholesterol) concentrations.

METHODS

In this crossover study, 36 adults with LDL cholesterol above 110 mg/dL consumed 48 g/d of 3 corn flour types for 4 wk: whole-grain corn meal, refined corn meal (RCM), and a blend of RCM and corn bran (RCM + B). We assessed the impact on cardiometabolic markers [LDL cholesterol, high-density lipoprotein cholesterol (HDL cholesterol), total cholesterol, and triglycerides)] and GM composition and estimated function. Statistical analyses included mixed-effects modeling and responder (>5% decrease in LDL cholesterol) analysis to evaluate changes in GM related to lipid profile improvements.

RESULTS

Of the 3 corn flour types, only RCM + B significantly decreased LDL cholesterol over time (-10.4 ± 3.6 mg/dL, P = 0.005) and marginally decreased total cholesterol (-9.2 ± 3.9 mg/dL, P = 0.072) over time. There were no significant effects on HDL cholesterol or triglyceride concentrations. No significant changes were observed in GM alpha diversity, whereas beta diversity metrics indicated individual variability. Two genera, unclassified Lachnospiraceae and Agathobaculum (Padj ≤ 0.096), differed significantly by treatment, but only Agathobaculum remained significantly elevated in the whole-grain corn meal, compared to RCM and RCM + B, after adjustment for multiple comparisons.

CONCLUSIONS

The type of corn flour, particularly RCM + B, notably influenced LDL cholesterol concentrations in adults with elevated LDL cholesterol. This study suggests that incorporating milled fractions (e.g., bran) of whole-grain corn with refined corn flour may be a viable alternative to supplementing manufactured grain products with isolated or synthetic fibers for improved metabolic health. This trial was registered at clinicaltrials.gov as NCT03967990.

Effects of salidroside on atherosclerosis: potential contribution of gut microbiota

Much research describes gut microbiota in atherosclerotic cardiovascular diseases (ASCVD) for that the composition of the intestinal microbiome or its metabolites can directly participate in the development of endothelial dysfunction, atherosclerosis and its adverse complications. Salidroside, a natural phenylpropane glycoside, exhibits promising biological activity against the progression of ASCVD. Recent studies suggested that the gut microbiota played a crucial role in mediating the diverse beneficial effects of salidroside on health. Here, we describe the protective effects of salidroside against the progression of atherosclerosis. Salidroside regulates the abundance of gut microbiotas and gut microbe-dependent metabolites. Moreover, salidroside improves intestinal barrier function and maintains intestinal epithelial barrier function integrity. In addition, salidroside attenuates the inflammatory responses exacerbated by gut microbiota disturbance. This review delves into how salidroside functions to ameliorate atherosclerosis by focusing on its interaction with gut microbiota, uncovering the potential roles of gut microbiota in the diverse biological impacts of salidroside.

Genetic screening and metabolomics identify glial adenosine metabolism as a therapeutic target in Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder and lacks disease-modifying therapies. We developed a Drosophila model for identifying novel glial-based therapeutic targets for PD. Human alpha-synuclein is expressed in neurons and individual genes are independently knocked down in glia. We performed a forward genetic screen, knocking down the entire Drosophila kinome in glia in alpha-synuclein expressing flies. Among the top hits were five genes (Ak1, Ak6, Adk1, Adk2, and awd) involved in adenosine metabolism. Knockdown of each gene improved locomotor dysfunction, rescued neurodegeneration, and increased brain adenosine levels. We determined that the mechanism of neuroprotection involves adenosine itself, as opposed to a downstream metabolite. We dove deeper into the mechanism for one gene, Ak1, finding rescue of dopaminergic neuron loss, alpha-synuclein aggregation, and bioenergetic dysfunction after glial Ak1 knockdown. We performed metabolomics in Drosophila and in human PD patients, allowing us to comprehensively characterize changes in purine metabolism and identify potential biomarkers of dysfunctional adenosine metabolism in people. These experiments support glial adenosine as a novel therapeutic target in PD.

Digestive dynamics: Unveiling interplay between the gut microbiota and the liver in macronutrient metabolism and hepatic metabolic health

Although the liver is the largest metabolic organ in the body, it is not alone in functionality and is assisted by "an organ inside an organ," the gut microbiota. This review attempts to shed light on the partnership between the liver and the gut microbiota in the metabolism of macronutrients (i.e., proteins, carbohydrates, and lipids). All nutrients absorbed by the small intestines are delivered to the liver for further metabolism. Undigested food that enters the colon is metabolized further by the gut microbiota that produces secondary metabolites, which are absorbed into portal circulation and reach the liver. These microbiota-derived metabolites and co-metabolites include ammonia, hydrogen sulfide, short-chain fatty acids, secondary bile acids, and trimethylamine N-oxide. Further, the liver produces several compounds, such as bile acids that can alter the gut microbial composition, which can in turn influence liver health. This review focuses on the metabolism of these microbiota metabolites and their influence on host physiology. Furthermore, the review briefly delineates the effect of the portosystemic shunt on the gut microbiota-liver axis, and current understanding of the treatments to target the gut microbiota-liver axis.

The gut microbiome in disorders of gut-brain interaction

Functional gastrointestinal disorders (FGIDs), chronic disorders characterized by either abdominal pain, altered intestinal motility, or their combination, have a worldwide prevalence of more than 40% and impose a high socioeconomic burden with a significant decline in quality of life. Recently, FGIDs have been reclassified as disorders of gut-brain interaction (DGBI), reflecting the key role of the gut-brain bidirectional communication in these disorders and their impact on psychological comorbidities. Although, during the past decades, the field of DGBIs has advanced significantly, the molecular mechanisms underlying DGBIs pathogenesis and pathophysiology, and the role of the gut microbiome in these processes are not fully understood. This review aims to discuss the latest body of literature on the complex microbiota-gut-brain interactions and their implications in the pathogenesis of DGBIs. A better understanding of the existing communication pathways between the gut microbiome and the brain holds promise in developing effective therapeutic interventions for DGBIs.

Entamoeba muris mitigates metabolic consequences of high-fat diet in mice

Metabolic syndrome (MetS) is a cluster of several human conditions including abdominal obesity, hypertension, dyslipidemia, and hyperglycemia, all of which are risk factors of type 2 diabetes, cardiovascular disease, and metabolic dysfunction-associated steatotic liver disease (MASLD). Dietary pattern is a well-recognized MetS risk factor, but additional changes related to the modern Western life-style may also contribute to MetS. Here we hypothesize that the disappearance of amoebas in the gut plays a role in the emergence of MetS in association with dietary changes. Four groups of C57B/6J mice fed with a high-fat diet (HFD) or a normal diet (ND) were colonized or not with Entamoeba muris, a commensal amoeba. Seventy days after inoculation, cecal microbiota, and bile acid compositions were analyzed by high-throughput sequencing of 16S rDNA and mass spectrometry, respectively. Cytokine concentrations were measured in the gut, liver, and mesenteric fat looking for low-grade inflammation. The impact of HFD on liver metabolic dysfunction was explored by Oil Red O staining, triglycerides, cholesterol concentrations, and the expression of genes involved in β-oxidation and lipogenesis. Colonization with E. muris had a beneficial impact, with a reduction in dysbiosis, lower levels of fecal secondary bile acids, and an improvement in hepatic steatosis, arguing for a protective role of commensal amoebas in MetS and more specifically HFD-associated MASLD.

Gut microbiota-derived fatty acid and sterol metabolites: biotransformation and immunomodulatory functions

Commensal microorganisms in the human gut produce numerous metabolites by using small molecules derived from the host or diet as precursors. Host or dietary lipid molecules are involved in energy metabolism and maintaining the structural integrity of cell membranes. Notably, gut microbes can convert these lipids into bioactive signaling molecules through their biotransformation and synthesis pathways. These microbiota-derived lipid metabolites can affect host physiology by influencing the body's immune and metabolic processes. This review aims to summarize recent advances in the microbial transformation and host immunomodulatory functions of these lipid metabolites, with a special focus on fatty acids and steroids produced by our gut microbiota.