Anti-inflammatory properties of the short-chain fatty acids acetate and propionate: A study with relevance to inflammatory bowel disease

The impact of gut microbial short-chain fatty acids on colorectal cancer development and prevention

Cancer is a long-term illness that involves an imbalance in cellular and immune functions. It can be caused by a range of factors, including exposure to environmental carcinogens, poor diet, infections, and genetic alterations. Maintaining a healthy gut microbiome is crucial for overall health, and short-chain fatty acids (SCFAs) produced by gut microbiota play a vital role in this process. Recent research has established that alterations in the gut microbiome led to decreased production of SCFA's in lumen of the colon, which associated with changes in the intestinal epithelial barrier function, and immunity, are closely linked to colorectal cancer (CRC) development and its progression. SCFAs influence cancer progression by modifying epigenetic mechanisms such as DNA methylation, histone modifications, and non-coding RNA functions thereby affecting tumor initiation and metastasis. This suggests that restoring SCFA levels in colon through microbiota modulation could serve as an innovative strategy for CRC prevention and treatment. This review highlights the critical relationship between gut microbiota and CRC, emphasizing the potential of targeting SCFAs to enhance gut health and reduce CRC risk.

Effect of probiotics on C-reactive protein levels in schizophrenia: Evidence from a systematic review and meta-analysis

BACKGROUND

Inflammatory markers play a pivotal role in schizophrenia, as they provide insight into the neuroinflammatory processes occurring in the context of the disorder. Elevated levels of these markers, particularly C-reactive protein (CRP), can indicate an underlying immune system dysregulation, potentially influencing symptom severity and progression. Recognizing these markers has led to investigate the use of probiotics as an adjuvant to improve the treatment of schizophrenia. The main objective of this study is to rigorously evaluate the efficacy of probiotics in reducing plasma levels of CRP in patients with schizophrenia.

METHODS

A systematic search and meta-analysis were conducted to review randomized clinical trials following the PRISMA methodology. The following search strategy ((SCHIZO* OR PSYCHOTIC OR PSYCHOSES) AND (PROBIOTIC* OR BIFIDOBACTER* OR LACTOBACILL*)) was used for searching publications between June-December 2024 on the PubMed, Web of Science, and APA PsycINFO databases. Individual study quality was assessed with the Cochrane risk of bias (RoB2) and the certainty of total evidence was assessed with the GRADE system.

RESULTS

The primary outcome assessed was the impact of probiotic supplementation on plasma CRP levels. Out of 78 studies initially identified, 4 were finally included in the meta-analysis. Three out four studies found a significant reduction in high-sensitivity C-reactive protein levels in the supplemented compared with the placebo group. The pooled analysis revealed a significant reduction in CRP levels with probiotic supplementation, with a standardized mean difference (SMD) of -0.46, (95 % CI -0.719; -0.201; p = 0.001).

CONCLUSIONS

The synthesis and meta-analysis of available literature provide evidence for the potential role of probiotics in the reduction of serum CRP in schizophrenia compared with placebo. However, more clinical trials with better control of experimental design are needed before a clear recommendation as adjuvant therapy can be made.

Allicin Improves Diet-Induced Nonalcoholic Steatohepatitis and Gut Microbiota Dysbiosis in Mice via the Involvement of the Circadian Clock Gene Rev-erbα

Nonalcoholic Steatohepatitis (NASH) is a progressive liver disease characterized by inflammation and liver damage. Allicin, a bioactive compound derived from garlic, has demonstrated anti-inflammatory and antioxidant properties. This study explores the effects of allicin on NASH and gut microbiota dysbiosis induced by a high-fat, high-fructose diet (HFFD) in mice. Allicin supplementation significantly alleviated hepatic inflammation, improved glucose metabolism, and modulated the circadian rhythm gene Rev-erbα, which plays a critical role in regulating inflammation. The anti-inflammatory effects of allicin were diminished in Si-Rev-erbα-treated HepG2 cells, highlighting the importance of circadian regulation in mediating these effects. Allicin's anti-inflammatory effects were associated with increased levels of short-chain fatty acids (SCFAs) and the restoration of diurnal oscillations in proinflammatory cytokines and gut microbiota composition, particularly in genera, such as Akkermansia, Bacteroidetes, and Lactobacillus. These findings suggest that allicin could be a promising therapeutic approach for managing NASH, liver dysfunction, and related metabolic disorders through the modulation of circadian rhythms and the gut microbiome.

Examination of Anti-Inflammatory Effects After Propionate Supplementation in the R6/2 Mouse Model of Huntington's Disease

Huntington's disease is a progressive, untreatable neurodegenerative disorder caused by a mutation in the Huntingtin gene. Next to neurodegeneration, altered immune activation is involved in disease progression. Since central nervous system inflammation and dysfunction of immune cells are recognized as driving characteristics, immunomodulation might represent an additional therapeutic strategy. Short-chain fatty acids were known to have immunomodulatory effects in neuroinflammatory diseases, such as multiple sclerosis. In this study, R6/2 mice were treated daily with 150 mM propionate. Survival range, body weight, and motor abilities were monitored. In striatal and cortical samples, neuronal survival was analyzed by immunofluorescence staining of NeuN-positive cells and expression levels of BDNF mRNA by real-time polymerase chain reaction. As inflammatory marker TNFα mRNA and IL-6 mRNA were quantified by rtPCR, iNOS-expressing cells were counted in immunologically stained brain slides. Microglial activation was evaluated by immunofluorescent staining of IBA1-positive cells and total IBA1 protein by Western Blot, in addition, SPI1 mRNA expression was quantified by rtPCR. Except for clasping behavior, propionate treatment did neither improve the clinical course nor mediated neuronal protection in R6/2 mice. Yet there was a mild anti-inflammatory effect in the CNS, with (i) reduction in SPI1-mRNA levels, (ii) reduced iNOS positive cells in the motor cortex, and (iii) normalized TNFα-mRNA in the motor cortex of propionate-treated R6/2 mice. Thus, Short-chain fatty acids, as an environmental factor in the diet, may slightly alleviate symptoms by down-regulating inflammatory factors in the central nervous system. However, they cannot prevent clinical disease progression or neuronal loss.

Ginger Extract Improves Cognitive Dysfunction via Modulation of Gut Microbiota-Derived Short-Chain Fatty Acids in D-Galactose/Ovariectomy-Induced Alzheimer-Like Disease

Alzheimer's disease (AD) is the most common form of dementia with complex causes and limited treatment options. Recent research has suggested a connection between the progression of AD and the activity of gut microbiota. Ginger, a plant known for its anti-inflammatory, antioxidant, and neuroprotective properties, has gained attention as a potential treatment for alleviating AD symptoms. In this study, we induced an AD model in female rats through ovariectomy and D-galactose injection and then investigated the protective effects of oral administration of ginger ethanolic extract. We assessed changes in short-chain fatty acids (SCFAs), learning and memory abilities, neuroinflammatory markers in plasma, and the hippocampus, as well as histological changes in the intestine and hippocampus in sham-operated, diseased, and treatment groups. Oral administration of ginger ethanolic extract improved gut microbiota activity, increased SCFA levels, and enhanced the expression of tight junction proteins. Additionally, ginger extract reduced the concentrations of TNF-α and IL-1β in both plasma and the hippocampus. Furthermore, it significantly reduced cell death and amyloid plaque deposition in the hippocampal tissue. These physiological changes resulted in improved performance in learning and memory tasks in rats treated with ginger compared with the disease group. These findings provide compelling evidence for the beneficial effects of ginger on the gut-brain axis, leading to improvements in learning and memory through the reduction of neuroinflammation.

Potential causal association between gut microbiota, inflammatory cytokines, and acute pancreatitis: A Mendelian randomization study

Background

Acute pancreatitis (AP) ranks among the most frequently encountered gastrointestinal diseases in the emergency department. Recent studies have increasingly emphasized the substantial connection among gut microbiota, inflammatory cytokines, and AP.

Methods

A two-sample Mendelian randomization (MR) study was conducted using summary statistics of gut microbiota (GM) from the largest available meta-analysis of genome-wide association studies conducted by the MiBioGen consortium (n=18,340). For cytokines, the data were obtained from a study that investigated genome variant associations with 41 inflammatory cytokines and growth factors (n=8293). The summary statistics of AP were obtained from the FinnGen consortium version R5 data (3022 cases and 195,144 controls). The inverse variance weighted (IVW) method was used as the main analysis, with MR-Egger and weighted median as complementary analytical methods. Sensitivity analyses were performed using Cochran's Q-test, MR-Egger intercept test, leave-one-out analyses, and MR-PRESSO. In addition, we employed the reverse MR analysis and MR Steiger method to estimate the orientations of exposure and outcome.

Result

Among the 211 examined GM taxa, the IVW method revealed that Bacteroidales (odds ratio [OR]=1.412, 95% confidence interval [CI]:1.057 to 1.885, P=0.019), Eubacterium fissicatena group (OR=1.240, 95% CI:1.045 to 1.470, P=0.014), and Coprococcus3 (OR=1.481, 95 % CI:1.049 to 2.090, P=0.026) exhibited a positive association with AP. Conversely, Prevotella9 (OR=0.821, 95% CI:0.680 to 0.990, P=0.038), RuminococcaceaeUCG004 (OR=0.757, 95% CI:0.577 to 0.994, P=0.045), and Ruminiclostridium6 (OR=0.696, 95% CI:0.548 to 0.884, P=0.003) displayed a negative correlation with AP. Among the 41 inflammatory cytokines, only macrophage colony-stimulating factor (M_CSF, OR=0.894, 95% CI:0.847 to 0.943, P=0.037) exhibited a negative association with AP. Sensitivity analyses revealed no evidence of pleiotropy or heterogeneity. Nevertheless, the mediation analysis showed that M_CSF did not act as a mediating factor.

Conclusion

This two-sample MR study revealed causal associations between specific GM and inflammatory cytokines with AP, respectively. However, inflammatory cytokines did not appear to act as mediating factors in the pathway from GM to AP.

Can consumption of traditional fermented foods protect against Hashimoto's thyroiditis?

BACKGROUND

this study examined fermented food consumption habits and the relationship between other factors and Hashimoto's thyroiditis.

METHODS

the study included 90 children and their mothers, 45 of whom had HT and 45 of whom did not. Participants answered a survey questioning about their fermented food consumption habits and the status of various environmental factors.

RESULTS

mothers who consumed homemade pickles during pregnancy (OR: 0.341, [95 % CI: 0.117 to 0.990]) homemade yogurt (OR: 0.091, [95 % CI: 0.011 to 0.752]), tarhana (OR: 0.325 [95 % CI: 0.136 to 0.778)]) and olive oil (OR: 0.163 [95 % CI: 0.033 to 0.792]) were found to have a statistically significant lower risk of developing Hashimoto's disease in their children. The risk of HT in children who consumed homemade yogurt (OR: 0.091 [95 % CI: 0.011 to 0.752]), cheese (OR: 0.242 [95 % CI: 0.100 to 0.590]), and olive oil (OR: 0.042 [95 % CI: 0.002 to 0.750]) was found to be significantly lower than in children who did not consume it.

CONCLUSIONS

fermented food consumption habits can be protective against autoimmune diseases such as HT by affecting the immune system through the intestinal microbiota.

Dietary Fibre Modulates Body Composition, Blood Glucose, Inflammation, Microbiome, and Metabolome in a Murine Model of Periodontitis

Background: Dietary fibre plays a crucial role in metabolic regulation, inflammation, and microbiome composition. However, its impact on systemic and oral health, particularly in periodontitis, remains unclear. This study investigated the effects of high- and low-fibre diets on body composition, glycaemic control, inflammation, microbiome, and metabolome in a murine model of experimental periodontitis. Methods: Thirty-six male C57BL/6 mice were randomised to a high-fibre (40% fibre) or low-fibre (5% fibre) diet for eight weeks. Body weight, fat mass, lean mass, fasting blood glucose, serum inflammatory markers, alveolar bone loss, and root length were assessed. Oral and faecal microbiome composition was analysed using 16S rRNA sequencing. Metabolomic and short-chain fatty acid (SCFA) profiling was conducted using liquid chromatography-mass spectrometry (LC-MS). Results: Mice on the high-fibre diet exhibited significantly lower body weight (p < 0.0001), fat mass (p = 0.0007), and lean mass (p < 0.0001) compared to the low-fibre group. Fasting blood glucose levels were significantly lower in the high-fibre group (p = 0.0013). TNF-α and IFN-γ levels were significantly elevated in the low-fibre group (p < 0.0001), suggesting a heightened pro-inflammatory state. While alveolar bone loss and root length did not differ significantly, microbiome analysis revealed distinct bacterial compositions (PERMANOVA, p < 0.05), with fibre-fermenting taxa enriched in high-fibre-fed mice. Metabolomic analysis identified 19 significantly altered metabolites, indicating dietary adaptations. Conclusions: A high-fibre diet improves glycaemic control, reduces systemic inflammation, and alters microbial and metabolic profiles in experimental periodontitis. These findings highlight dietary fibre's role in modulating metabolic and inflammatory pathways relevant to periodontal and systemic diseases.

The Gut-Brain-Microbiota Connection and Its Role in Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a group of complex neurodevelopmental conditions with a heterogeneous and multifactorial etiology that is not yet fully understood. Among the various factors that may contribute to ASD development, alterations in the gut microbiota have been increasingly recognized. Microorganisms in the gastrointestinal tract play a crucial role in the gut-brain axis (GBA), affecting nervous system development and behavior. Dysbiosis, or an imbalance in the microbiota, has been linked to both behavioral and gastrointestinal (GI) symptoms in individuals with ASD. The microbiota interacts with the central nervous system through mechanisms such as the production of short-chain fatty acids (SCFAs), the regulation of neurotransmitters, and immune system modulation. Alterations in its composition, including reduced diversity or an overabundance of specific bacterial taxa, have been associated with the severity of ASD symptoms. Dietary modifications, such as gluten-free or antioxidant-rich diets, have shown potential for improving gut health and alleviating behavioral symptoms. Probiotics, with their anti-inflammatory properties, may support neural health and reduce neuroinflammation. Fecal microbiota transplantation (FMT) is being considered, particularly for individuals with persistent GI symptoms. It has shown promising outcomes in enhancing microbial diversity and mitigating GI and behavioral symptoms. However, its limitations should be considered, as discussed in this narrative review. Further research is essential to better understand the long-term effects and safety of these therapies. Emphasizing the importance of patient stratification and phenotype characterization is crucial for developing personalized treatment strategies that account for individual microbiota profiles, genetic predispositions, and coexisting conditions. This approach could lead to more effective interventions for individuals with ASD. Recent findings suggest that gut microbiota may play a key role in innovative therapeutic approaches to ASD management.

To explore the potential combined treatment strategy for colorectal cancer: Inhibition of cancer stem cells and enhancement of intestinal immune microenvironment

BACKGROUND

The antibiotic salinomycin, a well-known cancer stem cell inhibitor, may impact the diversity of the intestinal microbiota in colorectal cancer (CRC) mice, which plays a pivotal role in shaping the immune system. This study explores the anti-cancer effects and mechanisms of combining salinomycin and fecal microbiota transplantation (FMT) in treating CRC.

METHODS

FMT was given via enema, while salinomycin was injected intraperitoneally into the CRC mouse model induced by azoxymethane/dextran sodium sulfate.

RESULTS

In CRC mice, a large number of LGR5-labeled cancer stem cells and severe disturbances in the intestinal microbiota were observed. Interestingly, salinomycin inhibited the proliferation of cancer stem cells without exacerbating the microbial disorder as expected. In comparison to salinomycin treatment, the combination of salinomycin and FMT significantly improved pathological damage and restored intestinal microbial diversity, which is responsible for shaping the anti-cancer immune microenvironment. The supplementation of FMT significantly increased the levels of propionic acid and butyric acid while also promoting the infiltration of CD8+ T cells and Ly6G+ neutrophils, as well as reducing F4/80+ macrophage recruitment. Notably, cytokines that were not impacted by salinomycin exhibited robust reactions to alterations in the gut microbiota. These included pro-inflammatory factors (IL6, IL12b, IL17, and IL22), chemokine-like protein OPN, and immunosuppressive factor PD-L1.

CONCLUSIONS

Salinomycin plays the role of "eliminating pathogenic qi," targeting cancer stem cells; FMT plays the role of "strengthening vital qi," reversing the intestinal microbiota disorder and enhancing anti-cancer immunity. They have a synergistic effect on the development of CRC.

Propionyl-CoA carboxylase subunit B regulates anti-tumor T cells in a pancreatic cancer mouse model

Most human pancreatic ductal adenocarcinoma (PDAC) are not infiltrated with cytotoxic T cells and are highly resistant to immunotherapy. Over 90% of PDAC have oncogenic KRAS mutations, and phosphoinositide 3-kinases (PI3Ks) are direct effectors of KRAS. Our previous study demonstrated that ablation of Pik3ca in KPC (KrasG12D; Trp53R172H; Pdx1-Cre) pancreatic cancer cells induced host T cells to infiltrate and completely eliminate the tumors in a syngeneic orthotopic implantation mouse model. Now, we show that implantation of Pik3ca-/- KPC (named αKO) cancer cells induces clonal enrichment of cytotoxic T cells infiltrating the pancreatic tumors. To identify potential molecules that can regulate the activity of these anti-tumor T cells, we conducted an in vivo genome-wide gene-deletion screen using αKO cells implanted in the mouse pancreas. The result shows that deletion of propionyl-CoA carboxylase subunit B gene (Pccb) in αKO cells (named p-αKO) leads to immune evasion, tumor progression, and death of host mice. Surprisingly, p-αKO tumors are still infiltrated with clonally enriched CD8+ T cells but they are inactive against tumor cells. However, blockade of PD-L1/PD1 interaction reactivated these clonally enriched T cells infiltrating p-αKO tumors, leading to slower tumor progression and improve survival of host mice. These results indicate that Pccb can modulate the activity of cytotoxic T cells infiltrating some pancreatic cancers and this understanding may lead to improvement in immunotherapy for this difficult-to-treat cancer.

Type of diet has no major influence on inflammatory response in a Saddleback pig model

Fermentable carbohydrates and resulting short-chain fatty acids (SCFAs) received attention via modifying potential on obesity-associated systemic low-grade inflammation. However, their effects on inflammation remain poorly understood. In this study, the anti-inflammatory properties of pectin or inulin supplementation were investigated in an atherogenic-fed pig obesity model. Pigs were divided into three atherogenic-fed groups with or without 5% pectin/inulin supplementation (AD, ADp, ADi, n = 10) and a conventional-fed group (CD, n = 10) for a 15-week feeding period. We demonstrated that faecal SCFA concentrations decreased and faecal pH increased in all groups over the feeding period (P < 0.05). SCFA concentrations were comparable between colon and faeces in all groups. Liver inflammatory-marker expressions were on average < 1 in all groups, except TNF-α (AD < CD and ADi; P < 0.01). Inflammatory-marker expressions in abdominal adipose tissue exceeded subcutaneous marker expressions in all groups. AD showed significantly lower IL-1β and CD68 mRNA levels than CD (P < 0.03). Comparing the atherogenic diet groups, the IL-1β mRNA levels were higher in ADi versus AD and ADp (P = 0.02). Our data indicated that fermentable carbohydrates added to an atherogenic diet cannot resolve low-grade adipose tissue inflammatory associated with obesity.

Sea urchin immune cells and associated microbiota co-exposed to iron oxide nanoparticles activate cellular and molecular reprogramming that promotes physiological adaptation

The innate immune system is the first player involved in the recognition/interaction with nanomaterials. Still, it is not the only system involved. The co-evolution of the microbiota with the innate immune system built an interdependence regulating immune homeostasis that is poorly studied. Herein, the simultaneous interaction of iron-oxide nanoparticles (Fe-oxide NPs), immune cells, and the microbiota associated with the blood of the sea urchin Paracentrotus lividus was explored by using a microbiota/immune cell model in vitro-ex vivo and a battery of complementary tools, including Raman spectroscopy, 16S Next-Generation Sequencing, high-content imaging, NanoString nCounter. Our findings highlight the P. lividus immune cells and microbiota dynamics in response to Fe-oxide NPs, including i) morphological rearrangement and immune cell health status maintenance (intracellular trafficking increasing, no phenotypic alterations or caspase 3/7 activation), ii) transcriptomic reprogramming in immune cells (Smad6, Lmo2, Univin, suPaxB, Frizzled-7, Fgfr2, Gp96 upregulation), iii) immune signaling unchanged (e.g., P-p38 MAPK, P-ERK, TLR4, IL-6 protein level unchanged), iv) enrichment in extracellular vesicle released in the co-culture medium, and v) a shift in the composition of microbial groups mainly in favor of Gram-positive bacteria (e.g., Firmicutes, Actinobacteria),. Our findings suggest that Fe-oxide NPs induce a multi-level immune cell-microbiota response restoring homeostasis.

Microbiota-derived metabolites in inflammatory bowel disease

Understanding the role of the gut microbiota in the pathogenesis of inflammatory bowel diseases (IBD) has been an area of intense research over the past decades. Patients with IBD exhibit alterations in their microbial composition compared to healthy controls. However, studies focusing solely on taxonomic analyses have struggled to deliver replicable findings across cohorts regarding which microbial species drive the distinct patterns in IBD. The focus of research has therefore shifted to studying the functionality of gut microbes, especially by investigating their effector molecules involved in the immunomodulatory functions of the microbiota, namely metabolites. Metabolic profiles are altered in IBD, and several metabolites have been shown to play a causative role in shaping immune functions in animal models. Therefore, understanding the complex communication between the microbiota, metabolites, and the host bears great potential to unlock new biomarkers for diagnosis, disease course and therapy response as well as novel therapeutic options in the treatment of IBD. In this review, we primarily focus on promising classes of metabolites which are thought to exert beneficial effects and are generally decreased in IBD. Though results from human trials are promising, they have not so far provided a large-scale break-through in IBD-therapy improvement. We therefore propose tailored personalized supplementation of microbiota and metabolites based on multi-omics analysis which accounts for the individual microbial and metabolic profiles in IBD patients rather than one-size-fits-all approaches.

Gut Microbiome Regulation of Gut Hormone Secretion

The gut microbiome, comprising bacteria, viruses, fungi, and bacteriophages, is one of the largest microbial ecosystems in the human body and plays a crucial role in various physiological processes. This review explores the interaction between the gut microbiome and enteroendocrine cells (EECs), specialized hormone-secreting cells within the intestinal epithelium. EECs, which constitute less than 1% of intestinal epithelial cells, are key regulators of gut-brain communication, energy metabolism, gut motility, and satiety. Recent evidence shows that gut microbiota directly influence EEC function, maturation, and hormone secretion. For instance, commensal bacteria regulate the production of hormones like glucagon-like peptide 1 and peptide YY by modulating gene expression and vesicle cycling in EE cells. Additionally, metabolites such as short-chain fatty acids, derived from microbial fermentation, play a central role in regulating EEC signaling pathways that affect metabolism, gut motility, and immune responses. Furthermore, the interplay between gut microbiota, EECs, and metabolic diseases, such as obesity and diabetes, is examined, emphasizing the microbiome's dual role in promoting health and contributing to disease states. This intricate relationship between the gut microbiome and EECs offers new insights into potential therapeutic strategies for metabolic and gut disorders.

Role of AIM2 and cGAS-STING signaling in high fat high carbohydrate diet-induced gut dysbiosis associated neurodegeneration

AIMS

Gut dysbiosis modulates CNS complications and cognitive decline through the gut-brain axis. The study aims to investigate the molecular mechanisms involved in gut dysbiosis-associated cognitive changes and the potential effects of probiotics in high fat-high carbohydrate diet-induced gut dysbiosis-associated neurodegeneration.

MATERIALS AND METHODS

We used high fat, high-carbohydrate diet (HFHCD) and high-fat diet (HFD) to induce gut dysbiosis-associated neurodegeneration in C57BL/6 mice. IVIS imaging system and biochemical changes using ELISA measured intestinal inflammation. We used fecal samples for qPCR profiling of intestinal bacteria, and serum was used for inflammatory marker analysis using ELISA. Behavioral studies measured cognitive changes, while histopathology, immunohistochemistry, and western blot analysis of hippocampal samples measured protein changes.

KEY FINDINGS

The behavioral studies showed a significant decrease in cognitive function associated with gut dysbiosis in HFHCD and HFD animals. Gut dysbiosis was associated with intestinal inflammation and increased intestinal permeability, followed by systemic and neuroinflammatory changes. Molecular signaling studies showed the involvement of AIM2 inflammasome and cGAS-STING signaling pathways in neurodegeneration for HFHCD animals. Administration of probiotics restored the above processes and prevented gut dysbiosis-associated memory decline in mice.

SIGNIFICANCE

The study shows that alteration in microbial composition due to prolonged HFHCD could contribute to intestinal inflammation and increased intestinal permeability, facilitating the translocation of microbial toxins like LPS, leading to systemic inflammation, which eventually leads to neuroinflammation and neurodegeneration.

The role of short-chain fatty acid in metabolic syndrome and its complications: focusing on immunity and inflammation

Metabolic syndrome (Mets) is an important contributor to morbidity and mortality in cardiovascular, liver, neurological, and reproductive diseases. Short-chain fatty acid (SCFA), an organismal energy donor, has recently been demonstrated in an increasing number of studies to be an important molecule in ameliorating immuno-inflammation, an important causative factor of Mets, and to improve lipid distribution, blood glucose, and body weight levels in animal models of Mets. This study reviews recent research advances on SCFA in Mets from an immune-inflammatory perspective, including complications dominated by chronic inflammation, as well as the fact that these findings also contribute to the understanding of the specific mechanisms by which gut flora metabolites contribute to metabolic processes in humans. This review proposes an emerging role for SCFA in the inflammatory Mets, followed by the identification of major ambiguities to further understand the anti-inflammatory potential of this substance in Mets. In addition, this study proposes novel strategies to modulate SCFA for the treatment of Mets that may help to mitigate the prognosis of Mets and its complications.

Short-chain fatty acids and cancer

Short-chain fatty acids (SCFAs), derived from the diet and the microbiota, serve as crucial links between the diet, gut microbiota, metabolism, immunity, and cancer. They function as energy sources through β-oxidation and regulate macromolecular synthesis, G protein-coupled receptor (GPCR) and histone deacetylase (HDAC) activities, protein modifications, signaling pathways, and gene expression in cells within the tumor microenvironment, particularly in tumor and immune cells. The critical role of SCFAs in maintaining normal homeostasis and influencing tumor progression highlights the potential of targeting SCFA-mediated cellular processes for cancer prevention and treatment.

The connection between fatty acids and inflammation in celiac disease; a deep exploring

The interplay between fatty acids (FAs) and celiac disease (CD) is a burgeoning field of research with significant implications for understanding the pathophysiology and potential therapeutic avenues for this autoimmune disorder. CD, triggered by gluten consumption in susceptible individuals, presents with a range of intestinal and extra-intestinal symptoms impacting various bodily functions. The disruption of intestinal tight junctions (TJs) by gluten proteins leads to increased gut permeability and subsequent inflammatory responses mediated by T-cells. FAs, crucial components of cell membranes, play diverse roles in inflammation and immune regulation. In fact, FAs have been shown to modulate inflammatory processes through various mechanisms. Studies have highlighted alterations in FA profiles in individuals with CD, indicating potential implications for disease pathogenesis and micronutrient deficiencies. Moreover, the exploration of FAs as biomarkers for CD diagnosis offers promising avenues for future research and therapeutic interventions. Understanding the intricate relationship between FAs and CD could lead to novel approaches in managing this complex autoimmune disorder. Therefore, this review article aims to provide an overview of the connection between FAs and inflammation in CD.

Investigate the metabolic changes in intestinal diseases by employing a 1H-NMR-based metabolomics approach on Caco-2 cells treated with cedrol

Mitochondrial dysfunction may precipitate intestinal dysfunction, while inflammatory bowel disease manifests as a chronic inflammatory ailment affecting the gastrointestinal tract. This condition disrupts the barrier function of the intestinal epithelium and alters metabolic products. Increasing mitochondrial adenosine triphosphate (ATP) synthesis in intestinal epithelial cells presents a promising avenue for colitis treatments. Nevertheless, the impact of cedrol on ATP and the intestinal barrier remains unexplored. Hence, this study is dedicated to examining the cedrol's protective effect on an inflammatory cocktail (IC)-induced intestinal epithelial barrier dysfunction in Caco-2 cells. The finding reveals that cedrol enhances ATP content and the transepithelial electrical resistance value in the intestinal epithelial barrier. Moreover, cedrol mitigates the IC-induced decrease in the messenger ribonucleic acid (mRNA) expression of tight junction proteins (ZO-1, Occludin, and Claudin-1), thereby ameliorating intestinal epithelial barrier dysfunction. Furthermore, nuclear magnetic resonance (NMR)-based metabolomic analysis indicated that IC-exposed Caco-2 cells are restored by cedrol treatments. Notably, cedrol elevates metabolites such as amino acids, thereby enhancing the intestinal barrier. In conclusion, cedrol alleviates IC-induced intestinal epithelial barrier dysfunction by promoting ATP-dependent proliferation of Caco-2 cells and bolstering amino acid levels to sustain tight junction messenger ribonucleic acid expression.

Dietary Mulberry leaf 1-deoxynijirimycin supplementation shortens villus height and improves intestinal barrier in fattening rabbits

OBJECTIVE

The current study investigated the effects of mulberry 1-deoxynijirimycin (DNJ) on the digestion ability, intestinal morphology, and intestinal barrier of rabbits.

METHODS

A total of 36 New Zealand White rabbits (male) about 45 days old (mean body weight of 1.05±0.04 kg) were reared and commercial diets were employed, and afterwards divided into three groups (n = 12) with different levels of DNJ extract additive in feed: T0 (0 g/kg), T1 (0.35 g/kg), T2 (0.7 g/kg) for 28 d.

RESULTS

The results demonstrated that T2 decreased the average daily gain (p<0.05). T1 and T2 decreased villus height and inflammatory factor levels as compared with T0 (p<0.05). DNJ significantly decreased the content of valeric acid (p<0.05). The content of acetic acid, propionic acid, iso butyric acid, iso valeric acid in T1 were higher than those in T0 and T2 (p<0.05). The content of butyric acid in T2 was lower than it in T0 and T1 (p<0.05). The content of caproic acid was firstly improved then reduced as the DNJ concentration improved (p<0.05). T2 significantly increased the abundance of dgA-11_gut_group and Christensenellaceae_R-7_group while decreased Bacteroide and Ralstonia as compared with T0 (p<0.05). Compared with T0, T1, and T2 significantly improved the gene expression of JAM2, JAM3, mucin4, mucin6 (p<0.05), T1 significantly decreased the expression of occluding while T2 significantly increased (p<0.05), T2 significantly increased the expression of claudin1 and claudin2 (p<0.05).

CONCLUSION

DNJ at high level changed microbiome compositions, inhibited inflammation, and improved intestinal barrier while it decreased the growth performance and shorted villus height in rabbit jejunum by regulating short chain fatty acid compositions in rabbits.

Transplant of gut microbiota ameliorates metabolic and heart disorders in rats fed with a hypercaloric diet by modulating microbial metabolism and diversity

Metabolic syndrome (MS) is a cluster of metabolic disorders which have a tight correlation with dysbiosis of gut microbiota (GM) that have to be treated to avoid higher risks for health. In this work, probiotics obtained from healthy cultured GM were provided to rats with metabolic syndrome (MSR) as therapy in treating MS through the correction of dysbiosis. MSR showed obesity, high blood pressure, abnormal blood chemistry parameters and high heart rate respect to control rats (CNTR). Cultivated GM from feces of MSR in media favoring anaerobic species, showed dysbiosis as judged by differences in the 16S rRNA metabarcoding analysis and by affected intermediary metabolism (methane and SCFA production, nutrients consumption and enzyme activities) compared to CNTR. The metabarcoding analysis of cultured healthy GM identified 211 species, which were further transplanted alive in MSR once a week for 9 weeks. Thereafter, in transplanted MSR the excess of Clostridium and Lactobacillus diminished, while Prevotella, Eubacterium, Faecalibacterium and methanogens, among others increased, leading to the recovery of the microbial metabolic capacity. The presence of butyric acid-producing bacteria in the transplanted GM correlated with increased levels of anti-inflammatory cytokines. Therefore, transplanted MSR recovered the normal levels of weight, blood glucose, triglycerides and cholesterol as well as the heart function. Data suggested that the great diversity of species contained in the GM transplanted restored the microbial metabolism, consuming excessive nutrients and secondary metabolites produced by MS. The use of cultivated GM as probiotics may be a safer alternative for the treatment of different diseases.

Recent Advances in Gut Microbiome Modulation: Effect of Probiotics, Prebiotics, Synbiotics, and Postbiotics in Inflammatory Bowel Disease Prevention and Treatment

The human gastrointestinal tract contains trillions of microbes that affect the body. Dysbiosis in the composition of gut microbiota is one of the leading causes of chronic inflammatory diseases such as inflammatory bowel disease (IBD). IBD is a global public health challenge and millions of people in the world are suffering from this disease. It is a recurring inflammatory disease that affects different parts of the human digestive system. Ulcerative colitis and Crohn's disease are the two main types of IBD with similar clinical symptoms. The increasing incidence and severity of IBD require new treatment methods. The composition of the gut microbiota can be modified using dietary supplements such as prebiotics and bacterial supplements called probiotics. Furthermore, the effects of the microbiome can be improved by using paraprobiotics (non-viable, inactivated bacteria or their components) and/or postbiotics (products of bacterial metabolism).

Genetically predict the association between 91 human blood cell perturbation phenotypes and IBD: A Mendelian randomization study

Inflammatory bowel disease (IBD), encompassing Crohn disease and ulcerative colitis, is a group of persistent and recurrent gastrointestinal disorders. Despite the prevalence of these conditions, no studies have been conducted to examine the connection between altered human blood cell phenotypes and the underlying mechanisms of IBD pathogenesis. By utilizing summary statistics from genome-wide association studies, we executed a systematic two-sample Mendelian randomization (MR) investigation on 91 genetically determined blood cell perturbation traits in relation to 3 separate IBD phenotypes. Our analysis sought to delineate the putative causal links between these blood cell perturbation phenotypes and IBD, thereby contributing to a more nuanced comprehension of the pathophysiological underpinnings and offering a foundation for the development of novel therapeutic approaches. The forward MR analysis identified 7 human blood cell perturbation phenotypes associated with various IBD outcomes, while the reverse MR analysis revealed that 9 human blood cell perturbation phenotypes were influenced by various IBD phenotypes. The study has uncovered human blood cell perturbation phenotypes associated with various IBD diseases, contributing to a deeper understanding of the pathogenesis of IBD. It also provides new insights for early clinical diagnosis, disease activity monitoring, immune surveillance, prognosis assessment, and personalized treatment.

A cross-section study of the comparison of plasma inflammatory cytokines and short-chain fatty acid in patients with depression and schizophrenia

BACKGROUND

Major depressive disorder (MDD) and schizophrenia (SCH) are common and severe mental disorders that are mainly diagnosed depending on the subjective identification by psychiatrists. Finding potential objective biomarkers that can distinguish these two diseases is still meaningful.

METHODS

In the present study, we investigate the differences in plasma inflammatory cytokines and short-chain fatty acids (SCFAs) among patients with MDD (n = 24) and SCH (n = 24), and gender- and age-matched healthy controls (HC, n = 27) and identify potential plasma biomarkers.

RESULTS

We found that the concentrations of pro-inflammatory cytokines were increased, whereas the anti-inflammatory cytokines were decreased in both MDD and SCH. Meanwhile, except for an increase in 4-Methylvaleric acid, other SCFAs with statistical differences were reduced in both MDD and SCH. Moreover, potential biomarker panels were developed that can effectively discriminate MDD from HC (AUC = 0.997), SCH from HC (AUC = 0.999), and from each other (MDD from SCH, AUC = 0.983).

CONCLUSIONS

These data suggest that alterations in plasma cytokines and SCFAs might be one of the potential features for distinguishing MDD and SCH.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR2100051243, registration date: 2021/09/16.

A triad of gut dysbiosis, dysregulated immunity, and 'leaky' gut characterize HCMV associated neonatal cholestasis

BACKGROUND

Gut microbiome dysbiosis and related immune dysfunction have been associated with the pathogenesis of Human Cytomegalovirus (HCMV) infection in infants with neonatal cholestasis (NC) as previously reported by us. However, the interaction of a perturbed microbiome, HCMV infection, and dysregulated immunity leading to exacerbation of disease severity has not been investigated so far. In this study, we examined the association of gut microbiome, host inflammatory and homeostatic markers that are likely to govern increased pathogenesis of NC in HCMV infected IgM positive infants (N = 15) compared to IgM negative (N = 15) individuals. Stool samples of HCMV infected infants and age-matched healthy controls (N = 10) were assessed for gut bacteria-derived metabolites like short-chain fatty acids (SCFAs), Lipopolysaccharide (LPS), cytokines and markers of gut barrier integrity. Data were correlated with previously determined gut microbiome composition and frequency of immune cell subsets. Finally, validation of clinical potential was undertaken by principal component analysis (PCA) of integrated data to delineate the spectrum of clinical pathology.

RESULTS

Significantly lower levels of SCFAs and elevated fecal levels of soluble inflammatory mediators were observed in IgM positive HCMV infected infants. Further, increased plasma LPS levels and markers of gut permeability, suggestive of microbial translocation due to a 'leaky gut' were observed in HCMV infected IgM positive group. PCA of integrated data revealed clearly disparate profiles representative of IgM positive, IgM negative, and uninfected healthy states.

CONCLUSION

Our results suggest the utility of an integrated approach involving dysregulated microbiome-immune axis for gaining a better understanding of pathogenesis associated with HCMV infection in NC.

Clinical Phenotypes Associated with the Gut Microbiome in Older Japanese People with Care Needs in a Nursing Home

BACKGROUND

Frailty increases the risk of needing nursing care and significantly affects the life and functional prognosis of older individuals. Early detection and tailored interventions are crucial for maintaining and enhancing their life functions. Recognizing distinct clinical phenotypes is essential for devising appropriate interventions. This study aimed to explore diverse frailty phenotypes, focusing on poor nutrition in older Japanese individuals through observational research.

METHODS

Twenty-one nursing home residents underwent a comprehensive survey covering physical, blood, dietary, cardiac, cognitive, nutritional, nursing care, frailty, agitated behavior, and gut microbiome assessments (high-throughput 16S rRNA gene sequencing). Using clustering analysis with 239 survey items (excluding gut microbiome), participants were classified into subgroups based on clinical phenotypes, and group characteristics were compared through analysis.

RESULTS

Individuals with moderate or severe frailty and suspected dementia formed subgroups with distinct clinical phenotypes based on nutritional, defecation, and nursing care statuses. The gut microbiome significantly varied among these groups (p = 0.007), indicating its correlation with changes in clinical phenotype. Nutritional status differences suggested poor nutrition as a differentiating factor in the core clinical phenotype.

CONCLUSIONS

This study proposes that the gut microbiome differs based on the clinical phenotype of Japanese older individuals with frailty, and targeted interventions addressing the gut microbiome may contribute to preventing frailty in this population.

SARS-CoV-2 infection is associated with intestinal permeability, systemic inflammation, and microbial dysbiosis in hospitalized patients

Coronavirus disease 2019 (COVID-19) and its associated severity have been linked to uncontrolled inflammation and may be associated with changes in the microbiome of mucosal sites including the gastrointestinal tract and oral cavity. These sites play an important role in host-microbe homeostasis, and disruption of epithelial barrier integrity during COVID-19 may potentially lead to exacerbated inflammation and immune dysfunction. Outcomes in COVID-19 are highly disparate, ranging from asymptomatic to fatal, and the impact of microbial dysbiosis on disease severity is unclear. Here, we obtained plasma, rectal swabs, oropharyngeal swabs, and nasal swabs from 86 patients hospitalized with COVID-19 and 12 healthy volunteers. We performed 16S rRNA sequencing to characterize the microbial communities in the mucosal swabs and measured concentrations of circulating cytokines, markers of gut barrier integrity, and fatty acids in the plasma samples. We compared these plasma concentrations and microbiomes between healthy volunteers and COVID-19 patients, some of whom had unfortunately died by the end of the study enrollment, and performed a correlation analysis between plasma variables and bacterial abundances. Rectal swabs of COVID-19 patients had reduced abundances of several commensal bacteria including Faecalibacterium prausnitzii and an increased abundance of the opportunistic pathogens Eggerthella lenta and Hungatella hathewayi. Furthermore, the oral pathogen Scardovia wiggsiae was more abundant in the oropharyngeal swabs of COVID-19 patients who died. The abundance of both H. hathewayi and S. wiggsiae correlated with circulating inflammatory markers including IL-6, highlighting the possible role of the microbiome in COVID-19 severity and providing potential therapeutic targets for managing COVID-19.IMPORTANCEOutcomes in coronavirus disease 2019 (COVID-19) are highly disparate and are associated with uncontrolled inflammation; however, the individual factors that lead to this uncontrolled inflammation are not fully understood. Here, we report that severe COVID-19 is associated with systemic inflammation, microbial translocation, and microbial dysbiosis. The rectal and oropharyngeal microbiomes of COVID-19 patients were characterized by a decreased abundance of commensal bacteria and an increased abundance of opportunistic pathogens, which positively correlated with markers of inflammation and microbial translocation. These microbial perturbations may, therefore, contribute to disease severity in COVID-19 and highlight the potential for microbiome-based interventions in improving COVID-19 outcomes.

Angiotensin-(1-7) improves intestinal microbiota disturbances and modulates fecal metabolic aberrations in acute pancreatitis

Acute pancreatitis (AP) is a serious health problem that dysregulates intestinal microbiota. Angiotensin (Ang)-(1-7) plays a protective role in the intestinal barrier in AP, but its effect on intestinal microbiota remains clear. To investigate the impact of Ang-(1-7) on AP-induced intestinal microbiota disorder and metabolites. We collected blood and fecal samples from 31 AP patients within 48 h after admission to the hospital, including 11 with mild AP (MAP), 14 with moderately severe AP (MSAP), six with severe AP (SAP). Mice were divided into four groups: control, AP, AP + Ang-(1-7) via tail vein injection, and AP + Ang-(1-7) via oral administration. The samples of mice were collected 12 h after AP. Pancreatic and intestinal histopathology scores were analyzed using the Schmidt and Chiu scores. Fecal microbiota and metabolites analysis was performed via 16S rDNA sequencing and nontargeted metabolomics analysis, respectively. In patients, the abundance of beneficial bacteria (Negativicutes) decreased and pathogenic bacteria (Clostridium bolteae and Ruminococcus gnavus) increased in SAP compared with MAP. Ang-(1-7) levels were associated with changes in the microbiota. There were differences in the intestinal microbiota between control and AP mice. Ang-(1-7) attenuated intestinal microbiota dysbiosis in AP mice, reflecting in the increase in beneficial bacteria (Odoribacter and Butyricimonas) than AP, as well as pancreatic and intestinal injuries. Oral administration of Ang-(1-7) reversing AP-induced decreases in metabolisms: secondary bile acids, emodin, and naringenin. Ang-(1-7) may improve intestinal microbiota dysbiosis and modulate fecal metabolites in AP, thereby reducing the damage of AP.

Gut Microbiota and Polycystic Ovary Syndrome (PCOS): Understanding the Pathogenesis and the Role of Probiotics as a Therapeutic Strategy

Polycystic ovary syndrome (PCOS) is one of the most common disorders among women in modern societies. A variety of factors can contribute to the development of PCOS. These women often exhibit high insulin resistance (IR), hyperandrogenism, irregular periods, and infertility. Dysbiosis of the gut microbiota (GMB) in women with PCOS has attracted the attention of many researchers. Porphyromonas spp., B. coprophilus, and F. prausnitzii are found in higher numbers in the gut of women with PCOS. Short-chain fatty acids (SCFAs), produced by the intestinal microbiota through fermentation, play an essential role in regulating metabolic activities and are helpful in reducing insulin resistance and improving PCOS symptoms. According to studies, the bacteria producing SCFAs in the gut of these women are less abundant than in healthy women. The effectiveness of using probiotic supplements has been proven to improve the condition of women with PCOS. Daily consumption of probiotics improves dysbiosis of the intestinal microbiome and increases the production of SCFAs.

Comprehensive modulatory effects of whole grain consumption on immune-mediated inflammation in middle-aged and elderly community residents: A real-world randomized controlled trial

BACKGROUND AND AIMS

Whole grain consumption is widely recognized as a vital component of a balanced diet. Dietary fiber has been well-documented to play a crucial role in these health benefits attributed to whole grain intake. However, population-based evidence directly linking whole grain consumption to anti-inflammatory effects, especially in the context of immune-mediated inflammation, remains limited. We hypothesized that whole grain consumption promotes health by modulating immune-mediated inflammation.

METHODS AND RESULTS

This study was designed as a real-world, population-based randomized controlled trial. We compared the effects of whole grain versus refined grain consumption on immune-mediated inflammation through staple food substitution, while participants maintained their usual dietary practices. The results demonstrated that whole grain consumption significantly reduced circulating levels of pro-inflammatory cytokines IL-22 and IL-23 compared to refined grain consumption. These reductions were associated with optimized short-chain fatty acid profiles and changes in CD4+ T cell subset distributions.

CONCLUSIONS

The findings suggest that the anti-inflammatory effects of whole grain consumption in middle-aged and elderly populations are mediated by targeting specific CD4+ T cell subsets, in addition to modulating both upstream short-chain fatty acid composition and downstream expression of the pro-inflammatory cytokines IL-22 and IL-23.

Bacterial epigenetics and its implication for agriculture, probiotics development, and biotechnology design

In their natural habitats, organisms encounter numerous external stimuli and must be able to sense and adapt to those stimuli to survive. Unlike mutations, epigenetic changes do not alter the underlying DNA sequence. Instead, they create modifications that promote or silence gene expression. Bacillus subtilis has long been a model organism in studying genetics and development. It is beneficial for numerous biotechnological applications where it is included as a probiotic, in fermentation, or in bio-concrete design. This bacterium has also emerged recently as a model organism for studying bacterial epigenetic adaptation. In this review, we examine the evolving knowledge of epigenetic regulation (restriction-modification systems (RM), orphan methyltransferases, and chromosome condensation) in B. subtilis and related bacteria, and utilize it as a case study to test their potential roles and future applications in genetic engineering and microbial biotechnology. Finally, we suggest how the implementation of these fundamental findings promotes the design of synthetic epigenetic memory circuits and their future applications in agriculture, medicine, and biotechnology.

Advances in the study of the relationship between gut microbiota and erectile dysfunction

INTRODUCTION

In recent years, in-depth research has revealed that gut microbiota has an inseparable relationship with erectile dysfunction (ED) in men.

OBJECTIVES

(1) To review the correlation between gut microbiota and ED from the perspective of its impact on men's mental health, metabolism, immunity, and endocrine regulation and (2) to provide reference to further explore the pathogenesis of ED and the improvement of clinical treatment plans.

METHODS

PubMed was used for the literature search to identify publications related to ED and gut microbiota.

RESULTS

Gut microbiota may induce depression and anxiety through the microbiota-gut-brain axis, leading to the occurrence of psychological ED. It may also cause vascular endothelial dysfunction and androgen metabolism disorder by interfering with lipid metabolism, immunity, and endocrine regulation, leading to the occurrence of organic ED.

CONCLUSION

Gut microbiota and its metabolites play an important role in the occurrence and development of ED. As a new influencing factor of ED, gut microbiota disorder is expected to become a target for treatment.

Mechanisms Underlying Obesity-induced Aβ Accumulation in Alzheimer's Disease: A Qualitative Review

Epidemiological studies show that individuals with obesity are more likely to develop Alzheimer's disease (AD) than those who do not have obesity. However, the mechanisms underlying the relationship between obesity and AD are not entirely unclear. Here, we have reviewed and analyzed relevant articles published in the literature and found that obesity has correlation or potential increase in the levels of β-amyloid (Aβ) protein, which may explain why people with obesity are more likely to suffer from AD. Additionally, the published findings point to the roles of obesity-related metabolic disorders, such as diabetes, inflammation, oxidative stress, and imbalance in gut microbiota in Aβ accumulation caused by obesity. Therefore, in-depth experimental and clinical studies on these mechanisms in the future may help shed light on appropriate prevention and treatment strategies for AD, such as dietary changes and regular exercise to reverse or prevent obesity and related metabolic disorders.

Species-level characterization of the core microbiome in healthy dogs using full-length 16S rRNA gene sequencing

Despite considerable interest and research in the canine fecal microbiome, our understanding of its species-level composition remains incomplete, as the majority of studies have only provided genus-level resolution. Here, we used full-length 16S rRNA gene sequencing to characterize the fecal microbiomes of 286 presumed healthy dogs living in homes in North America who are devoid of clinical signs, physical conditions, medication use, and behavioral problems. We identified the bacterial species comprising the core microbiome and investigated whether a dog's sex & neuter status, age, body weight, diet, and geographic region predicted microbiome variation. Our analysis revealed that 23 bacterial species comprised the core microbiome, among them Collinsella intestinalis, Megamonas funiformis, Peptacetobacter hiranonis, Prevotella copri, and Turicibacter sanguinis. The 23 taxa comprised 75% of the microbiome on average. Sterilized females, dogs of intermediate body sizes, and those exclusively fed kibble tended to harbor the most core taxa. Host diet category, geographic region, and body weight predicted microbiome beta-diversity, but the effect sizes were modest. Specifically, the fecal microbiomes of dogs fed kibble were enriched in several core taxa, including C. intestinalis, P. copri, and Holdemanella biformis, compared to those fed raw or cooked food. Conversely, dogs on a raw food diet exhibited higher abundances of Bacteroides vulgatus, Caballeronia sordicola, and Enterococcus faecium, among others. In summary, our study provides novel insights into the species-level composition and drivers of the fecal microbiome in healthy dogs living in homes; however, extrapolation of our findings to different dog populations will require further study.

Effects of Resistant-Starch-Encapsulated Probiotic Cocktail on Intestines Damaged by 5-Fluorouracil

Probiotics and prebiotics have gained attention for their potential health benefits. However, their efficacy hinges on probiotic survival through the harsh gastrointestinal environment. Microencapsulation techniques provide a solution, with resistant starch (RS)-based techniques showing promise in maintaining probiotic viability. Specifically, RS-encapsulated probiotics significantly improved probiotic survival in gastric acid, bile salts, and simulated intestinal conditions. This study investigated the effects of a resistant-starch-encapsulated probiotic cocktail (RS-Pro) in the context of 5-fluorouracil (5-FU) chemotherapy, which frequently induces microbiota dysbiosis and intestinal mucositis. Female BALB/c mice were divided into three groups: a 5-FU group, a 5-FU+Pro group receiving free probiotics, and a 5-FU+RS-Pro group receiving RS-encapsulated probiotics. After 28 days of treatment, analyses were conducted on fecal microbiota, intestinal histology, peripheral blood cell counts, and body and organ weights. It was revealed by 16S rRNA MiSeq sequencing that 5-FU treatment disrupted gut microbiota composition, reduced microbial diversity, and caused dysbiosis. RS-Pro treatment restored microbial diversity and increased the population of beneficial bacteria, such as Muribaculaceae, which play roles in carbohydrate and polyphenol metabolism. Furthermore, 5-FU administration induced moderate intestinal mucositis, characterized by reduced cellularity and shortened villi. However, RS-Pro treatment attenuated 5-FU-induced intestinal damage, preserving villus length. Mild leukopenia observed in the 5-FU-treated mice was partially alleviated in 5-FU+Pro and 5-FU+RS-Pro groups. These findings suggest that RS-Pro may serve as an adjunct to chemotherapy, potentially reducing adverse effects and improving therapeutic outcomes in future clinical applications.

Probiotics in miRNA-Mediated Regulation of Intestinal Immune Homeostasis in Pigs: A Physiological Narrative

The microbiota plays a crucial role in maintaining the host's intestinal homeostasis, influencing numerous physiological functions. Various factors, including diet, stress, and antibiotic use, can lead to such imbalances. Probiotics have been shown to restore the microbiota, contributing to maintaining this balance. For instance, the weaning stage in piglets is crucial; this transition can cause unfavorable changes that may contribute to the onset of diarrhea. Probiotic supplementation has increased due to its benefits. However, its mechanism of action is still controversial; one involves the regulation of intestinal immunity. When recognized by immune system cells through membrane receptors, probiotics activate intracellular signaling pathways that lead to changes in gene expression, resulting in an anti-inflammatory response. This complex regulatory system involves transcriptional and post-transcriptional mechanisms, including the modulation of various molecules, emphasizing microRNAs. They have emerged as important regulators of innate and adaptive immune responses. Analyzing these mechanisms can enhance our understanding of probiotic-host microbiota interactions, providing insights into their molecular functions. This knowledge can be applied not only in the swine industry, but also in studying microbiota-related disorders. Moreover, these studies serve as animal models, helping to understand better conditions such as inflammatory bowel disease and other related disorders.

Exploring the Potential of Postbiotics for Food Safety and Human Health Improvement

Food safety is a global concern, with millions suffering from foodborne diseases annually. The World Health Organization (WHO) reports significant morbidity and mortality associated with contaminated food consumption, and this emphasizes the critical need for comprehensive food safety measures. Recent attention has turned to postbiotics, metabolic byproducts of probiotics, as potential agents for enhancing food safety. Postbiotics, including organic acids, enzymes, and bacteriocins, exhibit antimicrobial and antioxidant properties that do not require live organisms, and this offers advantages over probiotics. This literature review critically examines the role of postbiotics in gut microbiome modulation and applications in the food industry. Through an extensive review of existing literature, this study evaluates the impact of postbiotics on gut microbiome composition and their potential as functional food ingredients. Research indicates that postbiotics are effective in inhibiting food pathogens such as Staphylococcus aureus, Salmonella enterica, and Escherichia coli, as well as their ability to prevent oxidative stress-related diseases, and they also show promise as alternatives to conventional food preservatives that can extend food shelf life by inhibiting harmful bacterial growth. Their application in functional foods contributes to improved gut health and reduced risk of foodborne illnesses. Findings suggest that postbiotics hold promise for improving health and preservation by inhibiting pathogenic bacteria growth and modulating immune responses.

Allium tuberosum-derived nanovesicles with anti-inflammatory properties prevent DSS-induced colitis and modify the gut microbiome

Edible plant-derived nanovesicles (ePDNs) have shown potential as a non-pharmacological option for inflammatory bowel disease (IBD) by maintaining gut health and showing anti-inflammatory effects. However, the effects of Allium tuberosum-derived nanovesicles (ADNs) on colitis have not been studied to date. Here, we extracted exosome-like nanovesicles from Allium tuberosum and investigated whether they have an anti-inflammatory effect in RAW 264.7 cells and colitis mice. The results showed that ADNs reduced the elevated levels of inflammatory factors such as IL-1β, IL-6, TNF-α, and NF-κB pathway-related proteins as a consequence of lipopolysaccharide (LPS) stimulation in RAW 264.7 cells. Furthermore, our mouse experiments demonstrated that ADNs could ameliorate dextran sulfate sodium (DSS)-induced colitis symptoms (e.g., increased disease activity index score, intestinal permeability, and histological appearance). Additionally, ADNs counteracted DSS-induced colitis by downregulating the expression of serum amyloid A (SAA), IL-1β, IL-6, and TNF-α and increasing the expression of tight junction proteins (ZO-1 and occludin) and the anti-inflammatory cytokine IL-10. 16S rRNA gene sequencing showed that ADN intervention restored the gut microbial composition, which was similar to that of the DSS non-treated group, by decreasing the ratio of Firmicutes to Bacteroidetes and the relative abundance of Proteobacteria. Furthermore, ADNs induced acetic acid production along with an increase in the abundance of Lactobacillus. Overall, our findings suggest that ADN supplementation has a crucial role in maintaining gut health and is a novel preventive therapy for IBD.

Longitudinal gut microbial signals are associated with weight loss: insights from a digital therapeutics program

Introduction

The gut microbiome's influence on weight management has gained significant interest for its potential to support better obesity therapeutics. Patient stratification leading to personalized nutritional intervention has shown benefits over one-size-fit-all diets. However, the efficacy and impact on the gut's microbiome of personalizing weight loss diets based on individual factors remains under-investigated.

Methods

This study assessed the impact of Digbi Health's personalized dietary and lifestyle program on weight loss and the gut microbiome end-points in 103 individuals. Participants' weight loss patterns and gut microbiome profiles were analyzed from baseline to follow-up samples.

Results

Specific microbial genera, functional pathways, and communities associated with BMI changes and the program's effectiveness were identified. 80% of participants achieved weight loss. Analysis of the gut microbiome identified genera and functional pathways associated with a reduction in BMI, including Akkermansia, Christensenella, Oscillospiraceae, Alistipes, and Sutterella, short-chain fatty acid production, and degradation of simple sugars like arabinose, sucrose, and melibiose. Network analysis identified a microbiome community associated with BMI, which includes multiple taxa known for associations with BMI and obesity.

Discussion

The personalized dietary and lifestyle program positively impacted the gut microbiome and demonstrated significant associations between gut microbial changes and weight loss. These findings support the use of the gut microbiome as an endpoint in weight loss interventions, highlighting potential microbiome biomarkers for further research.

Microbiota-Derived Short-Chain Fatty Acids Boost Antitumoral Natural Killer Cell Activity

Background: The intestinal microbiota can regulate numerous host functions, including the immune response. Through fermentation, the microbiota produces and releases microbial metabolites such as short-chain fatty acids (SCFAs), which can affect host homeostasis. There is growing evidence that the gut microbiome can have a major impact on cancer. Specific gut microbial composition and metabolites are associated with tumor status in the host. However, their effects on the antitumor response have scarcely been investigated. Natural killer (NK) cells play an important role in antitumor immunity due to their ability to directly identify and eliminate tumor cells. Methods: The aim of this study was to investigate the effects of SCFAs on antitumoral NK cell activity, using NK-92 cell line. Results: Here, we describe how SCFAs can boost antitumoral NK cell activity. The SCFAs induced the release of NK extracellular vesicles and reduced the secretion of the anti-inflammatory cytokine IL-10. The SCFAs also increased the cytotoxicity of the NK cells against multiple myeloma cells. Conclusions: Our results indicate, for the first time, the enormous potential of SCFAs in regulating antitumoral NK cell defense, where modulation of the SCFAs' production could play a fundamental role in cancer immunotherapy.

Ameliorating effect of 2'-fucosyllactose and 6'-sialyllactose on lipopolysaccharide-induced intestinal inflammation

Human milk oligosaccharides (HMO) affect gut microbiota during neonatal development, particularly with respect to the immune system. Bovine milk-based infant formulas have low oligosaccharide contents. Thus, efforts to fortify infant formulas with HMO are being undertaken. Two major HMO, 2'-fucosyllactose (2'-FL) and 6'-sialyllactose (6'-SL), exert anti-inflammatory effects; however, the associations between anti-inflammatory effects induced by 2'-FL and 6'-SL cotreatment and gut microbiota composition and metabolite modulation remain unclear. Therefore, in this study, we evaluated the effects of a mixture of these HMO. To determine the optimal HMO ratio for anti-inflammatory effects and elucidate its mode of action, LPS-induced inflammatory HT-29 epithelial cells and intestinal-inflamed suckling mice were treated with various mixtures of 2'-FL and 6'-SL. A 2'-FL:6'-SL ratio of 5:1 was identified as the most effective pretreatment HMO mixture in vitro; thus, this ratio was selected and used for low-, middle-, and high-dose treatments for subsequent in vivo studies. In vivo, high-dose HMO treatment restored LPS-induced inflammation symptoms, such as BW loss, colon length reduction, histological structural damage, and intestinal gene expression related to inflammatory responses. High-dose HMO was the only treatment that modulated the major phyla Bacteroidetes and Firmicutes and the genera Ihubacter, Mageeibacillus, and Saccharofermentans. These changes in microbial composition were correlated with intestinal inflammation-related gene expression and short-chain fatty acid production. To our knowledge, our study is the first to report the effects of Ihubacter, Mageeibacillus, and Saccharofermentans on short-chain fatty acid levels, which can subsequently affect inflammatory cytokine and tight junction protein levels. Conclusively, the HMO mixture exerted anti-inflammatory effects through changes in microbiota and metabolite production. These findings suggest that supplementation of infant formula with HMO may benefit formula-fed infants by forming unique microbiota contributing to neonatal development.

Short-chain fatty acid levels in stools of patients with inflammatory bowel disease are lower than those in healthy subjects

OBJECTIVE

Short-chain fatty acids (SCFAs) are produced when the microbiota in the large intestine cause fermentation of dietary carbohydrates and fibers. These fatty acids constitute the primary energy source of colon mucosa cells and have a protective effect in patients suffering from inflammatory bowel disease (IBD). This study aimed to compare the SCFA levels in the stools of patients with IBD and healthy controls.

METHOD

Healthy controls and patients with IBD aged 18 and over were included in the study. Stool samples from all patients and healthy controls were collected, and stool acetic acid, propionic acid, and butyric acid levels were measured using a gas chromatography-mass spectrometry measurement method.

RESULTS

In this study, 64 participants were divided into two groups: 34 were in IBD (Crohn disease and ulcerative colitis) and 30 were in healthy control group. When fecal SCFA concentrations of IBD and healthy control groups were compared, a statistically significant difference was observed between them. When the fecal SCFA concentrations of Crohn's disease and ulcerative colitis patients in the IBD group were compared, however, no statistically significant difference was observed between them. Furthermore, when the participants' diet type (carbohydrate-based, vegetable-protein-based and mixed diet) and the number of meals were compared with fecal SCFA concentrations, no statistically significant difference was observed between them.

CONCLUSION

In general, fecal SCFA levels in patients with IBD were lower than those in healthy controls. Moreover, diet type and the number of meals had no effect on stool SCFA levels in patients with IBD and healthy individuals.

Human Gut Microbiota in Cardiovascular Disease

The gut ecosystem, termed microbiota, is composed of bacteria, archaea, viruses, protozoa, and fungi and is estimated to outnumber human cells. Microbiota can affect the host by multiple mechanisms, including the synthesis of metabolites and toxins, modulating inflammation and interaction with other organisms. Advances in understanding commensal organisms' effect on human conditions have also elucidated the importance of this community for cardiovascular disease (CVD). This effect is driven by both direct CV effects and conditions known to increase CV risk, such as obesity, diabetes mellitus (DM), hypertension, and renal and liver diseases. Cardioactive metabolites, such as trimethylamine N -oxide (TMAO), short-chain fatty acids (SCFA), lipopolysaccharides, bile acids, and uremic toxins, can affect atherosclerosis, platelet activation, and inflammation, resulting in increased CV incidence. Interestingly, this interaction is bidirectional with microbiota affected by multiple host conditions including diet, bile acid secretion, and multiple diseases affecting the gut barrier. This interdependence makes manipulating microbiota an attractive option to reduce CV risk. Indeed, evolving data suggest that the benefits observed from low red meat and Mediterranean diet consumption can be explained, at least partially, by the changes that these diets may have on the gut microbiota. In this article, we depict the current epidemiological and mechanistic understanding of the role of microbiota and CVD. Finally, we discuss the potential therapeutic approaches aimed at manipulating gut microbiota to improve CV outcomes. © 2024 American Physiological Society. Compr Physiol 14:5449-5490, 2024.

Inflammatory proteins may mediate the causal relationship between gut microbiota and inflammatory bowel disease: A mediation and multivariable Mendelian randomization study

This research investigates the causal relationships among gut microbiota, inflammatory proteins, and inflammatory bowel disease (IBD), including crohn disease (CD) and ulcerative colitis (UC), and identifies the role of inflammatory proteins as potential mediators. Our study analyzed gut microbiome data from 13,266 samples collected by the MiBioGen alliance, along with inflammatory protein data from recent research by Zhao et al, and genetic data on CD and UC from the International Inflammatory Bowel Disease Genetics Consortium (IIBDGC). We used Mendelian randomization (MR) to explore the associations, complemented by replication, meta-analysis, and multivariable MR techniques for enhanced accuracy and robustness. Our analysis employed several statistical methods, including inverse-variance weighting, MR-Egger, and the weighted median method, ensuring comprehensive and precise evaluation. After MR analysis, replication and meta-analysis, we revealed significant associations between 11 types of gut microbiota and 17 inflammatory proteins were associated with CD and UC. Mediator MR analysis and multivariable MR analysis showed that in CD, the CD40L receptor mediated the causal effect of Defluviitaleaceae UCG-011 on CD (mediation ratio 8.3%), and the Hepatocyte growth factor mediated the causal effect of Odoribacter on CD (mediation ratio 18%). In UC, the C-C motif chemokine 4 mediated the causal effect of Ruminococcus2 on UC (mediation ratio 4%). This research demonstrates the interactions between specific gut microbiota, inflammatory proteins, and CD and UC. Furthermore, the CD40L receptor may mediate the relationship between Defluviitaleaceae UCG-011 and CD; the Hepatocyte growth factor may mediate the relationship between Odoribacter and CD; and the C-C motif chemokine 4 may mediate the relationship between Ruminococcus2 and UC. The identified associations and mediation effects offer insights into potential therapeutic approaches targeting the gut microbiome for managing CD and UC.

Exploring the Relationship Between Diet, Lifestyle and Gut Microbiome in Colorectal Cancer Development: A Recent Update

Colorectal cancer (CRC) is one of the major causes of cancer-related mortality worldwide. Despite advances in treatment modalities, its prevalence continues to rise, notably among younger populations. Unhealthy dietary habits, sedentary routines, and obesity have been identified as one of the key contributors to the development of colorectal cancer, apart from genetic and epigenetic modifications. Recognizing the profound impact of diet and lifestyle on the intricate gut microbiota ecosystem offers a promising avenue for understanding CRC development and its treatment. Gut dysbiosis, characterized by imbalances favoring harmful microbes over beneficial ones, has emerged as a defining feature of CRC. Changes in diet and lifestyle can profoundly alter the composition of gut microbes and the metabolites they produce, potentially contributing to CRC onset. Focusing on recent evidence, this review discussed various dietary factors, such as high consumption of red and processed meats and low fiber intake, and lifestyle factors, including obesity, lack of physical activity, smoking, and excessive alcohol consumption, that influence the gut microbiome composition and elevate CRC risk.

A comparative evaluation of the kefir yeast Kluyveromyces marxianus A4 and sulfasalazine in ulcerative colitis: anti-inflammatory impact and gut microbiota modulation

Although only Saccharomyces boulardii has been studied for ulcerative colitis (UC), probiotic yeasts have immense therapeutic potential. Herein, we evaluated the kefir yeast Kluyveromyces marxianus A4 (Km A4) and its anti-inflammatory effect with sulfasalazine in BALB/c mice with dextran sulfate sodium (DSS)-induced colitis. Oral administration continued for 7 days after the mice were randomly divided into seven groups: control (CON, normal mice administered with saline), DSS-induced colitis mice administered saline (DSS), and DSS-induced colitis mice administered sulfasalazine only (S), Km A4 only (A4), Km A4 plus sulfasalazine (A4 + S), S. boulardii ATCC MYA-796 (Sb MYA-796) only (Sb), and Sb MYA-796 plus sulfasalazine (Sb + S). The β-glucan content of Km A4 was significantly higher than that of Sb MYA-796 (P < 0.05). Body weight gain (BWG) significantly correlated with colon length, cyclooxygenase-2 (Cox-2) levels, and Bacteroides abundance (P < 0.05). In colitis-induced mice, the A4 + S group had the lowest histological score (6.00) compared to the DSS group (12.67), indicating the anti-inflammatory effects of this combination. The A4 + S group showed significantly downregulated expression of interleukin (Il)-6, tumor necrosis factor-α (Tnf-α), and Cox-2 and upregulated expression of Il-10 and occludin (Ocln) compared to the DSS group. Mice treated with A4 + S had enhanced Bacteroides abundance in their gut microbiota compared with the DSS group (P < 0.05). Bacteroides were significantly correlated with all colitis biomarkers (BWG, colon length, Il-6, Tnf-α, Il-10, Cox-2, and Ocln; P < 0.05). The anti-inflammatory effects of Km A4 could be attributed to high β-glucan content and gut microbiota modulation. Thus, treatment with Km A4 and sulfasalazine could alleviate UC.

Exploring the interaction and impact of probiotic and commensal bacteria on vitamins, minerals and short chain fatty acids metabolism

There is increasing evidence that probiotic and commensal bacteria play a role in substrate metabolism, energy harvesting and intestinal homeostasis, and may exert immunomodulatory activities on human health. In addition, recent research suggests that these microorganisms interact with vitamins and minerals, promoting intestinal and metabolic well-being while producing vital microbial metabolites such as short-chain fatty acids (SCFAs). In this regard, there is a flourishing field exploring the intricate dynamics between vitamins, minerals, SCFAs, and commensal/probiotic interactions. In this review, we summarize some of the major hypotheses beyond the mechanisms by which commensals/probiotics impact gut health and their additional effects on the absorption and metabolism of vitamins, minerals, and SCFAs. Our analysis includes comprehensive review of existing evidence from preclinical and clinical studies, with particular focus on the potential interaction between commensals/probiotics and micronutrients. Finally, we highlight knowledge gaps and outline directions for future research in this evolving field.

Research progress in the treatment of inflammatory bowel disease with natural polysaccharides and related structure-activity relationships

Inflammatory bowel disease (IBD) comprises a group of highly prevalent and chronic inflammatory intestinal tract diseases caused by multiple factors. Despite extensive research into the causes of the disease, IBD's pathogenic mechanisms remain unclear. Moreover, side effects of current IBD therapies restrict their long-term clinical use. In contrast, natural polysaccharides exert beneficial anti-IBD effects and offer advantages over current anti-IBD drugs, including enhanced safety and straightforward isolation from abundant and reliable sources, and thus may serve as components of functional foods and health products for use in IBD prevention and treatment. However, few reviews have explored natural polysaccharides with anti-IBD activities or the relationship between polysaccharide conformation and anti-IBD biological activity. Therefore, this review aims to summarize anti-IBD activities and potential clinical applications of polysaccharides isolated from plant, animal, microorganismal, and algal sources, while also exploring the relationship between polysaccharide conformation and anti-IBD bioactivity for the first time. Furthermore, potential mechanisms underlying polysaccharide anti-IBD effects are summarized, including intestinal microbiota modulation, intestinal inflammation alleviation, and intestinal barrier protection from IBD-induced damage. Ultimately, this review provides a theoretical foundation and valuable insights to guide the development of natural polysaccharide-containing functional foods and nutraceuticals for use as dietary IBD therapies.

Nutrition, gastrointestinal microorganisms and metabolites in mastitis occurrence and control

Mastitis affects almost all mammals including humans and dairy cows. In the dairy industry, bovine mastitis is a disease with a persistently high incidence, causing serious losses to the health of cows, the quality of dairy products, and the economy of dairy farms. Although local udder infection caused by the invasion of exogenous pathogens into the mammary gland was considered the main cause of mastitis, evidence has been established and continues to grow, showing that nutrition factors and gastrointestinal microbiome (GM) as well as their metabolites are also involved in the development of mammary inflammatory response. Suboptimal nutrition is recognized as a risk factor for increased susceptibility to mastitis in cattle, in particular the negative energy balance. The majority of data regarding nutrition and bovine mastitis involves micronutrients. In addition, the dysbiotic GM can directly trigger or aggravate mastitis through entero-mammary gland pathway. The decreased beneficial commensal bacteria, lowered bacterial diversity, and increased pathogens as well as proinflammatory metabolites are found in both the milk and gastrointestinal tract of mastitic dairy cows. This review discussed the relationship between the nutrition (energy and micronutrient levels) and mastitis, summarized the role of GM and metabolites in regulating mastitis. Meanwhile, several non-antibiotics strategies were provided for the prevention and alleviation of mastitis, including micronutrients, probiotics, short-chain fatty acids, high-fiber diet, inulin, and aryl hydrocarbon receptor.