Microbiota-derived short-chain fatty acids and modulation of host-derived peptides formation: Focused on host defense peptides

Host-directed therapies modulating innate immunity against infection in hematologic malignancies

Patients with hematologic malignancies (HM) are highly susceptible to bloodstream infection (BSI), particularly those undergoing treatments such as chemotherapy. A common and debilitating side effect of chemotherapy is oral and intestinal mucositis. These Patients are also at high risk of developing sepsis, which can arise from mucosal barrier injuries and significantly increases mortality in these patients. While conventional antibiotics are effective, their use can lead to antimicrobial resistance (AMR) and disrupt the gut microbiota (dysbiosis). In this review, we discuss utilizing host defense peptides (HDPs), key components of the innate immune system, and immune system inducers (ISIs) to maintain mucosal barrier integrity against infection, an underexplored host-directed therapy (HDT) approach to prevent BSI and sepsis. We advocate for the discovery of potent and safe ISIs for clinical use and call for further research into the mechanisms by which these ISIs induce HDPs and strengthen mucosal barriers.

Postbiotics as Antiinflammatory and Immune-Modulating Bioactive Compounds in Metabolic Dysfunction-Associated Steatotic Liver Disease

Postbiotics, defined as products or metabolic byproducts secreted by live bacteria or released after bacterial lysis, are emerging as promising therapeutic agents for metabolic dysfunction-associated steatotic liver disease (MASLD). This review explores the antiinflammatory and immunomodulatory properties of various postbiotics, including exopolysaccharides, lipoteichoic acid, short-chain fatty acids, hydrogen sulfide, polyamines, tryptophan derivatives, and polyphenol metabolites. These compounds have demonstrated potential in mitigating steatotic liver infiltration, reducing inflammation, and slowing fibrosis progression in preclinical studies. Notably, postbiotics exert their beneficial effects by modulating gut microbiota composition, enhancing intestinal barrier function, optimizing lipid metabolism, reducing hepatic inflammation and steatosis, and exhibiting hepatoprotective properties. However, translating these findings into clinical practice requires well-designed trials to validate efficacy and safety, standardize production and characterization, and explore personalized approaches and synergistic effects with other therapeutic modalities. Despite challenges, the unique biological properties of postbiotics, such as enhanced safety compared to probiotics, make them attractive candidates for developing novel nutritional interventions targeting the multifactorial pathogenesis of MASLD. Further research is needed to establish their clinical utility and potential to improve liver and systemic outcomes in this increasingly prevalent condition.

Daikenchuto, a Japanese herbal medicine, ameliorates experimental colitis in a murine model by inducing secretory leukocyte protease inhibitor and modulating the gut microbiota

Background

Inflammatory bowel disease (IBD) is a refractory inflammatory disorder of the intestine, which is probably triggered by dysfunction of the intestinal epithelial barrier. Secretory leukocyte protease inhibitor (SLPI) secreted by colon epithelial cells protects against intestinal inflammation by exerting anti-protease and anti-microbial activities. Daikenchuto (DKT) is one of the most commonly prescribed Japanese traditional herbal medicines for various digestive diseases. Although several animal studies have revealed that DKT exerts anti-inflammatory effects, its detailed molecular mechanism is unclear. This study aimed to clarify the anti-inflammatory mechanism of DKT using a murine colitis model, and to evaluate its potential as a therapeutic agent for IBD.

Methods

Experimental colitis was induced in wild-type (WT) mice and SLPI-deficient (KO) mice by dextran sulfate sodium (DSS) after oral administration of DKT. The resultant clinical symptoms, histological changes, and pro-inflammatory cytokine levels in the colon were assessed. Expression of SLPI in the colon was detected by Western blotting and immunohistochemistry. Composition of the gut microbiota was analyzed by 16S rRNA metagenome sequencing and intestinal metabolites were measured by gas chromatography-mass spectrometry analysis. Intestinal epithelial barrier function was assessed by oral administration of FITC-dextran and immunostaining of tight junction proteins (TJPs).

Results

Oral administration of DKT increased the number of butyrate-producing bacteria, such as Parabacteroides, Allobaculum, and Akkermansia, enhanced the levels of short-chain fatty acids, including butyrate, in the colon, induced SLPI expression, and ameliorated DSS-induced colitis in WT mice. We found that mouse colon carcinoma cell line treatment with either DKT or butyrate significantly enhanced the expression of SLPI. Moreover, supplementation of DKT protected the intestinal epithelial barrier with augmented expression of TJPs in WT mice, but not in KO mice. Finally, the composition of the gut microbiota was changed by DKT in WT mice, but not in KO mice, suggesting that DKT alters the colonic bacterial community in an SLPI-dependent manner.

Conclusion

These results indicate that DKT exerts anti-inflammatory effects on the intestinal epithelial barrier by SLPI induction, due, at least in part, to increased butyrate-producing bacteria and enhanced butyrate levels in the colon. These results provide insight into the mechanism of the therapeutic effects of DKT on IBD.

Postbiotics as Adjuvant Therapy in Cancer Care

Postbiotics are defined as a preparation of inanimate microorganisms and/or their components that confers a health benefit to the host. They range from cell wall fragments to metabolites, bacterial lysates, extracellular vesicles, and short-chain fatty acids (SCFAs). Postbiotics may influence carcinogenesis via a variety of mechanisms. They can promote homeostatic immune responses, reduce inflammation, induce selective cytotoxicity against tumor cells, as well as the enabling the control of tumor cell proliferation and enhancing intestinal epithelial barrier function. Therefore, probiotics can serve as an adjunct strategy in anticancer treatment together with chemotherapy and immunotherapy. Up to now, the only relevant postbiotics used as interventions in oncological patients remain vitamin K molecules, with few phase-II and III trials available. In fact, postbiotics' levels are strictly dependent on the gut microbiota's composition, which may vary between individuals and can be altered under different physiological and pathological conditions. Therefore, the lack of consistent clinical evidence supporting postbiotics' efficacy is due to their poor bioavailability, short half-life, and fluctuating levels. Synbiotics, a mixture of prebiotics and probiotics, are expected to have a more homogeneous bioavailability with respect to postbiotics and may have greater potential for future development. In this review, we focus on the role of postbiotics as an adjuvant therapy in cancer treatment.

The Role of Intestinal Microbiota and Probiotics Supplementation in Multiple Sclerosis Management

Multiple sclerosis (MS) is a neurological autoimmune disorder predominantly afflicting young adults. The etiology of MS is intricate, involving a variety of environmental and genetic factors. Current research increasingly focuses on the substantial contribution of gut microbiota in MS pathogenesis. The commensal microbiota resident within the intestinal milieu assumes a central role within the intricate network recognized as the gut-brain axis (GBA), wielding beneficial impact in neurological and psychological facets. As a result, the modulation of gut microbiota is considered a pivotal aspect in the management of neural disorders, including MS. Recent investigations have unveiled the possibility of using probiotic supplements as a promising strategy for exerting a positive impact on the course of MS. This therapeutic approach operates through several mechanisms, including the reinforcement of gut epithelial integrity, augmentation of the host's resistance against pathogenic microorganisms, and facilitation of mucosal immunomodulatory processes. The present study comprehensively explains the gut microbiome's profound influence on the central nervous system (CNS). It underscores the pivotal role played by probiotics in forming the immune system and modulating neurotransmitter function. Furthermore, the investigation elucidates various instances of probiotic utilization in MS patients, shedding light on the potential therapeutic advantages afforded by this intervention.

The impact of the host microbiota on Candida albicans infection

The human microbiota is a complex microbial ecosystem populated by bacteria, fungi, viruses, protists, and archaea. The coexistence of fungi alongside with many billions of bacteria, especially in the gut, involves complex interactions, ranging from antagonistic to beneficial, between the members of these two kingdoms. Bacteria can impact fungi through various means, such as physical interactions, secretion of metabolites, or alteration of the host immune response, thereby affecting fungal growth and virulence. This review summarizes recent progress in this field, delving into the latest understandings of bacterial-fungal-immune interactions and innovative therapeutic approaches addressing the challenges of treating fungal infections associated with microbiota imbalances.

Relationship between gut microbiota and the pathogenesis of gestational diabetes mellitus: a systematic review

Introduction

Gestational diabetes mellitus (GDM) is a form of gestational diabetes mellitus characterized by insulin resistance and abnormal function of pancreatic beta cells. In recent years, genomic association studies have revealed risk and susceptibility genes associated with genetic susceptibility to GDM. However, genetic predisposition cannot explain the rising global incidence of GDM, which may be related to the increased influence of environmental factors, especially the gut microbiome. Studies have shown that gut microbiota is closely related to the occurrence and development of GDM. This paper reviews the relationship between gut microbiota and the pathological mechanism of GDM, in order to better understand the role of gut microbiota in GDM, and to provide a theoretical basis for clinical application of gut microbiota in the treatment of related diseases.

Methods

The current research results on the interaction between GDM and gut microbiota were collected and analyzed through literature review. Keywords such as "GDM", "gut microbiota" and "insulin resistance" were used for literature search, and the methodology, findings and potential impact on the pathophysiology of GDM were systematically evaluated.

Results

It was found that the composition and diversity of gut microbiota were significantly associated with the occurrence and development of GDM. Specifically, the abundance of certain gut bacteria is associated with an increased risk of GDM, while other changes in the microbiome may be associated with improved insulin sensitivity. In addition, alterations in the gut microbiota may affect blood glucose control through a variety of mechanisms, including the production of short-chain fatty acids, activation of inflammatory pathways, and metabolism of the B vitamin group.

Discussion

The results of this paper highlight the importance of gut microbiota in the pathogenesis of GDM. The regulation of the gut microbiota may provide new directions for the treatment of GDM, including improving insulin sensitivity and blood sugar control through the use of probiotics and prebiotics. However, more research is needed to confirm the generality and exact mechanisms of these findings and to explore potential clinical applications of the gut microbiota in the management of gestational diabetes. In addition, future studies should consider the interaction between environmental and genetic factors and how together they affect the risk of GDM.

Effect of the supplementation of exogenous complex non-starch polysaccharidases on the growth performance, rumen fermentation and microflora of fattening sheep

The objective of this study was to evaluate the effects of exogenous non-starch polysaccharidases (a mixture of cellulase, xylanase, β-glucanase and mannanase) on the growth performance and nutrient digestibility, rumen fermentation, and rumen microflora of sheep. The animal trial was conducted using 36 5-month-old female fattening hybrid sheep (Duolang♂ × Hu♀) who were randomly assigned into four groups comprising nine sheep per treatment: CON, T1, T2, and T3, with 0, 0.1, 0.3, and 0.5% NSPases/kg DM of TMR, respectively. This complex enzyme product was screened for optimal ratios based on previous in vitro tests and responded positively to the in vitro fermentation of the TMR. When treated with NSPases, there was a non-linear effect of average daily gain and feed conversion rate, with the greatest improvement observed in the T2 group. There were no significant differences (p > 0.05) in nutrient intake or apparent digestibility among the NSPase-supplemented groups. In addition, T2 group had a significantly higher acetate to propionate ratio and pH (p < 0.05) than the other groups, and NH3-N and microbial protein concentrations showed a quadratic curve. The results revealed that both immunoglobulins and serum hormones increased linearly with addition (p < 0.05). As the T2 group showed the best growth performance, the CON and T2 groups were subjected to rumen metagenomic analysis. The results showed higher abundance of bacteria and lower abundance of Viruses in the rumen microbiota of the T2 group compared to the CON group. In addition, Uroviricota and Proteobacteria abundance was significantly lower in the T2 group than in the CON group at the phylum level (p < 0.05). These results suggest that the supplementation of high-concentrate rations with NSPases enhance immunity, reduces virus abundance in the rumen, improves rumen health, and promotes rumen fermentation. Our findings provide novel insights for improving growth performance and alleviating inflammatory responses arising from high concentrate feeding patterns in ruminants. However, the biological mechanisms cannot be elucidated by exploring the composition of rumen microbe alone, and further studies are required.

Characterization of Wnt signaling pathway under treatment of Lactobacillus acidophilus postbiotic in colorectal cancer using an integrated in silico and in vitro analysis

Colorectal cancer (CRC) is a prevalent and life-threatening cancer closely associated with the gut microbiota. Probiotics, as a vital microbiota group, interact with the host's colonic epithelia and immune cells by releasing a diverse range of metabolites named postbiotics. The present study examined the effects of postbiotics on CRC's prominent differentially expressed genes (DEGs) using in silico and in vitro analysis. Through single-cell RNA sequencing (scRNA-seq), we identified four DEGs in CRC, including secreted frizzled-related protein 1 (SFRP1), secreted frizzled-related protein 2 (SFRP2), secreted frizzled-related protein 4 (SFRP4), and matrix metallopeptidase 7 (MMP7). Enrichment analysis and ExpiMap, a novel deep learning-based method, determined that these DEGs are involved in the Wnt signaling pathway as a primary cascade in CRC. Also, spatial transcriptome analysis showed specific expression patterns of the SFRP2 gene in fibroblast cell type. The expression of selected DEGs was confirmed on CRC and normal adjacent tissues using Real-Time quantitative PCR (RT-qPCR). Moreover, we examined the effects of postbiotics extracted from Lactobacillus acidophilus (L. acidophilus) on the proliferation, migration, and cell cycle distribution of HT-29 cells using MTT, scratch, and flow cytometry assays. Our results showed that L. acidophilus postbiotics induce cell cycle arrest at G1 phase and also had anti-proliferative and anti-migration effects on HT-29 cells, while it did not exert anti-proliferative activity on control fibroblasts. Finally, we revealed that treating HT-29 cells with postbiotics can affect the expression of selected DEGs. We suggested that L. acidophilus postbiotics have therapeutic potential in CRC by modulating key genes in the Wnt pathway.

Houttuynia cordata thunb. alleviates inflammatory bowel disease by modulating intestinal microenvironment: a research review

Inflammatory bowel disease (IBD) is a complex group of chronic intestinal diseases, the cause of which has not yet been clarified, but it is widely believed that the disorder of the intestinal microenvironment and its related functional changes are key factors in the development of the disease. Houttuynia cordata thunb. is a traditional plant with abundant resources and long history of utilization in China, which has attracted widespread attention in recent years due to its potential in the treatment of IBD. However, its development and utilization are limited owing to the aristolochic acid alkaloids contained in it. Therefore, based on the relationship between the intestinal microenvironment and IBD, this article summarizes the potential mechanisms by which the main active ingredients of Houttuynia cordata thunb., such as volatile oils, polysaccharides, and flavonoids, and related traditional Chinese medicine preparations, such as Xiezhuo Jiedu Formula, alleviate IBD by regulating the intestinal microenvironment. At the same time, combined with current reports, the medicinal and edible safety of Houttuynia cordata thunb. is explained for providing ideas for further research and development of Houttuynia chordate thunb. in IBD disease, more treatment options for IBD patients, and more insights into the therapeutic potential of plants with homology of medicine and food in intestinal diseases, and even more diseases.

Synergistic Strategies for Gastrointestinal Cancer Care: Unveiling the Benefits of Immunonutrition and Microbiota Modulation

Gastrointestinal (GI) cancers are a group of highly prevalent malignant tumors affecting the gastrointestinal tract. Globally, one in four cancer cases and one in three cancer deaths are estimated to be GI cancers. They can alter digestive and absorption functions, leading to severe malnutrition which may worsen the prognosis of the patients. Therefore, nutritional intervention and monitoring play a fundamental role in managing metabolic alterations and cancer symptoms, as well as minimizing side effects and increasing the effectiveness of chemotherapy. In this scenario, the use of immunonutrients that are able to modulate the immune system and the modification/regulation of the gut microbiota composition have gained attention as a possible strategy to improve the conditions of these patients. The complex interaction between nutrients and microbiota might contribute to maintaining the homeostasis of each individual's immune system; therefore, concurrent use of specific nutrients in combination with traditional cancer treatments may synergistically improve the overall care of GI cancer patients. This work aims to review and discuss the role of immunonutrition and microbiota modulation in improving nutritional status, postoperative recovery, and response to therapies in patients with GI cancer.

Prebiotics Progress Shifts in the Intestinal Microbiome That Benefits Patients with Type 2 Diabetes Mellitus

Hypoglycemic medications that could be co-administered with prebiotics and functional foods can potentially reduce the burden of metabolic diseases such as Type 2 Diabetes Mellitus (T2DM). The efficacy of drugs such as metformin and sulfonylureas can be enhanced by the activity of the intestinal microbiome elaborated metabolites. Functional foods such as prebiotics (e.g., oligofructose) and dietary fibers can treat a dysbiotic gut microbiome by enhancing the diversity of microbial niches in the gut. These beneficial shifts in intestinal microbiome profiles include an increased abundance of bacteria such as Faecalibacterium prauznitzii, Akkermancia muciniphila, Roseburia species, and Bifidobacterium species. An important net effect is an increase in the levels of luminal SCFAs (e.g., butyrate) that provide energy carbon sources for the intestinal microbiome in cross-feeding activities, with concomitant improvement in intestinal dysbiosis with attenuation of inflammatory sequalae and improved intestinal gut barrier integrity, which alleviates the morbidity of T2DM. Oligosaccharides administered adjunctively with pharmacotherapy to ameliorate T2DM represent current plausible treatment modalities.

Cystic Fibrosis and Cancer: Unraveling the Complex Role of CFTR Gene in Cancer Susceptibility

Cystic fibrosis (CF) is a genetic disorder affecting multiple organs, primarily the lungs and digestive system. Over the years, advancements in medical care and treatments have significantly increased the life expectancy of individuals with CF. However, with this improved longevity, concerns about the potential risk of developing certain types of cancers have arisen. This narrative review aims to explore the relationship between CF, increased life expectancy, and the associated risk for cancers. We discuss the potential mechanisms underlying this risk, including chronic inflammation, immune system dysregulation, and genetic factors. Additionally, we review studies that have examined the incidence and types of cancers seen in CF patients, with a focus on gastrointestinal, breast, and respiratory malignancies. We also explore the impact of CFTR modulator therapies on cancer risk. In the gastrointestinal tract, CF patients have an elevated risk of developing colorectal cancer, pancreatic cancer, and possibly esophageal cancer. The underlying mechanisms contributing to these increased risks are not fully understood, but chronic inflammation, altered gut microbiota, and genetic factors are believed to play a role. Regular surveillance and colonoscopies are recommended for early detection and management of colorectal cancer in CF patients. Understanding the factors contributing to cancer development in CF patients is crucial for implementing appropriate surveillance strategies and improving long-term outcomes. Further research is needed to elucidate the molecular mechanisms involved and develop targeted interventions to mitigate cancer risk in individuals with CF.

Advances in gut microbiome in metabonomics perspective: based on bibliometrics methods and visualization analysis

Background and aims

Gastrointestinal microbial metabolomics is closely related to the state of the organism and has significant interaction with the pathogenesis of many diseases. Based on the publications in Web of Science Core Collection(WoSCC) from 2004 to 2022, this study conducted a bibliometric analysis of this field, aiming to understand its development trend and frontier, and provide basic information and potential points for in-depth exploration of this field.

Methods

All articles on gastrointestinal flora and metabolism published from 2004 to 2022 were collected and identified in WoCSS. CiteSpace v.6.1 and VOSviewer v.1.6.15.0 were used to calculate bibliometric indicators, including number of publications and citations, study categories, countries/institutions, authors/co-cited authors, journals/co-cited journals, co-cited references, and keywords. A map was drawn to visualize the data based on the analysis results for a more intuitive view.

Results

There were 3811 articles in WoSCC that met our criteria. Analysis results show that the number of publications and citations in this field are increasing year by year. China is the country with the highest number of publications and USA owns the highest total link strength and citations. Chinese Acad Sci rank first for the number of institutional publications and total link strength. Journal of Proteome Research has the most publications. Nicholson, Jeremy K. is one of the most important scholars in this field. The most cited reference is "Gut flora metabolism of phosphatidylcholine promotes cardiovascular disease". Burst detection indicates that Urine, spectroscopy, metabonomic and gut microflora are long-standing hot topics in this field, while autism spectrum disorder and omics are likely to be at the forefront of research. The study of related metabolic small molecules and the application of gastrointestinal microbiome metabolomics in various diseases are currently emerging research directions and frontier in this field.

Conclusion

This study is the first to make a bibliometric analysis of the studies related to gastrointestinal microbial metabolomics and reveal the development trends and current research hotspots in this field. This can contribute to the development of the field by providing relevant scholars with valuable and effective information about the current state of the field.