The Bacterium Akkermansia muciniphila: A Sentinel for Gut Permeability and Its Relevance to HIV-Related Inflammation

HIV-associated neurocognitive disorder: key implications of the microbiota-gut-brain axis

HIV-associated neurocognitive disorder (HAND) is now recognized to be relatively common in people living with HIV (PLWH), and remains a common cause of cognitive impairment. Unfortunately, the fundamental pathogenic processes underlying this specific outcome of HIV infection have not as yet been fully elucidated. With increased interest in research related to the microbiota-gut-brain axis, the gut-brain axis has been shown to play critical roles in regulating central nervous system disorders such as Alzheimer's disease and Parkinson's disease. PLWH are characterized by a particular affliction, referred to as gut-associated dysbiosis syndrome, which provokes an alteration in microbial composition and diversity, and of their associated metabolite composition within the gut. Interestingly, the gut microbiota has also been recognized as a key element, which both positively and negatively influences human brain health, including the functioning and development of the central nervous system (CNS). In this review, based on published evidence, we critically discuss the relevant interactions between the microbiota-gut-brain axis and the pathogenesis of HAND in the context of HIV infection. It is likely that HAND manifestation in PLWH mainly results from (i) gut-associated dysbiosis syndrome and a leaky gut on the one hand and (ii) inflammation on the other hand. In other words, the preceding features of HIV infection negatively alter the composition of the gut microbiota (microbes and their associated metabolites) and promote proinflammatory immune responses which singularly or in tandem damage neurons and/or induce inadequate neuronal signaling. Thus, HAND is fairly prevalent in PLWH. This work aims to demonstrate that in the quest to prevent and possibly treat HAND, the gut microbiota may ultimately represent a therapeutically targetable "host factor."

Effect of inulin, galacto-oligosaccharides, and polyphenols on the gut microbiota, with a focus on Akkermansia muciniphila

Inulins, galacto-oligosaccharides (GOS) and polyphenols are considered to stimulate the growth of Akkermansia muciniphila (A. muciniphila) in the gut. We performed a meta-analysis of six microbiome studies (821 stool samples from 451 participants) to assess the effects of inulin, GOS, and polyphenols on the abundance of A. muciniphila in the gut. The intervention of GOS increased the relative abundance of A. muciniphila in healthy participants. Additionally, metabolic pathways associated with carbohydrate metabolism and short-chain fatty acid release were enriched following the GOS intervention. Furthermore, after the GOS intervention, the coexisting microbial communities of A. muciniphila, such as Eubacterium hallii and Bacteroides, exhibited an enhanced correlation with A. muciniphila. In conclusion, our findings suggest that GOS may promote the growth of A. muciniphila in the gut by modulating the gut microbiota composition.

A Critical Review on the Role of Probiotics in Lung Cancer Biology and Prognosis

Lung cancer remains the leading cause of cancer-related deaths worldwide. According to the American Cancer Society (ACS), it ranks as the second most prevalent type of cancer globally. Recent findings have highlighted bidirectional gut-lung interactions, known as the gut-lung axis, in the pathophysiology of lung cancer. Probiotics are live microorganisms that boost host immunity when consumed adequately. The immunoregulatory mechanisms of probiotics are thought to operate through the generation of various metabolites that impact both the gut and distant organs (e.g., the lungs) through blood. Several randomized controlled trials have highlighted the pivotal role of probiotics in gut health especially for the prevention and treatment of malignancies, with a specific emphasis on lung cancer. Current research indicates that probiotic supplementation positively affects patients, leading to a suppression in cancer symptoms and a shortened disease course. While clinical trials validate the therapeutic benefits of probiotics, their precise mechanism of action remains unclear. This narrative review aims to provide a comprehensive overview of the present landscape of probiotics in the management of lung cancer.

Gut permeability among Astronauts during Space missions

The space environment poses substantial challenges to human physiology, including potential disruptions in gastrointestinal health. Gut permeability has only recently become widely acknowledged for its potential to cause adverse effects on a systemic level, rendering it a critical factor to investigate in the context of spaceflight. Here, we propose that astronauts experience the onset of leaky gut during space missions supported by transcriptomic and metagenomic analysis of human and murine samples. A genetic map contributing to intestinal permeability was constructed from a systematic review of current literature. This was referenced against our re-analysis of three independent transcriptomic datasets which revealed significant changes in gene expression patterns associated with the gut barrier. Specifically, in astronauts during flight, we observed a substantial reduction in the expression genes that are crucial for intestinal barrier function, goblet cell development, gut microbiota modulation, and immune responses. Among rodent spaceflight studies, differential expression of cytokines, chemokines, and genes which regulate mucin production and post-translational modifications suggest a similar dysfunction of intestinal permeability. Metagenomic analysis of feces from two murine studies revealed a notable reduction probiotic, short chain fatty acid-producing bacteria and an increase in the Gram-negative pathogens, including Citrobacter rodentium, Enterobacter cloacea, Klebsiella aerogenes, and Proteus hauseri which promote LPS circulation, a recipe for barrier disruption and systemic inflammatory activation. These findings emphasize the critical need to understand the underlying mechanisms and develop interventions to maintain gastrointestinal health in space.

The Effect of Gut Microbiota-Targeted Interventions on Neuroinflammation and Motor Function in Parkinson's Disease Animal Models-A Systematic Review

Gut microbiome-targeted interventions such as fecal transplant, prebiotics, probiotics, synbiotics, and antibiotic gut depletion are speculated to be of potential use in delaying the onset and progression of Parkinson's disease by rebalancing the gut microbiome in the context of the gut-brain axis. Our study aims to organize recent findings regarding these interventions in Parkinson's disease animal models to identify how they affect neuroinflammation and motor outcomes. A systematic literature search was applied in PubMed, Web of Science, Embase, and SCOPUS for gut microbiome-targeted non-dietary interventions. Studies that investigated gut-targeted interventions by using in vivo murine PD models to follow dopaminergic cell loss, motor tests, and neuroinflammatory markers as outcomes were considered to be eligible. A total of 1335 studies were identified in the databases, out of which 29 were found to be eligible. A narrative systematization of the resulting data was performed, and the effect direction for the outcomes was represented. Quality assessment using the SYRCLE risk of bias tool was also performed. Out of the 29 eligible studies, we found that a significant majority report that the intervention reduced the dopaminergic cell loss (82.76%, 95% CI [64.23%, 94.15%]) produced by the induction of the disease model. Also, most studies reported a reduction in microglial (87.5%, 95% CI [61.65%, 98.45%]) and astrocytic activation (84,62%, 95% CI [54.55%, 98.08%]) caused by the induction of the disease model. These results were also mirrored in the majority (96.4% 95% CI [81.65%, 99.91%]) of the studies reporting an increase in performance in behavioral motor tests. A significant limitation of the study was that insufficient information was found in the studies to assess specific causes of the risk of bias. These results show that non-dietary gut microbiome-targeted interventions can improve neuroinflammatory and motor outcomes in acute Parkinson's disease animal models. Further studies are needed to clarify if these benefits transfer to the long-term pathogenesis of the disease, which is not yet fully understood. The study had no funding source, and the protocol was registered in the PROSPERO database with the ID number CRD42023461495.

The implication of microbiome in lungs cancer: mechanisms and strategies of cancer growth, diagnosis and therapy

Available evidence illustrates that microbiome is a promising target for the study of growth, diagnosis and therapy of various types of cancer. Lung cancer is a leading cause of cancer death worldwide. The relationship of microbiota and their products with diverse pathologic conditions has been getting large attention. The novel research suggests that the microbiome plays an important role in the growth and progression of lung cancer. The lung microbiome plays a crucial role in maintaining mucosal immunity and synchronizing the stability between tolerance and inflammation. Alteration in microbiome is identified as a critical player in the progression of lung cancer and negatively impacts the patient. Studies suggest that healthy microbiome is essential for effective therapy. Various clinical trials and research are focusing on enhancing the treatment efficacy by altering the microbiome. The regulation of microbiota will provide innovative and promising treatment strategies for the maintenance of host homeostasis and the prevention of lung cancer in lung cancer patients. In the current review article, we presented the latest progress about the involvement of microbiome in the growth and diagnosis of lung cancer. Furthermore, we also assessed the therapeutic status of the microbiome for the management and treatment of lung cancer.

Longitudinal analysis of microbiome composition in Ghanaians living with HIV-1

Human immunodeficiency virus (HIV) 1 infection is known to cause gut microbiota dysbiosis. Among the causes is the direct infection of HIV-1 in gut-resident CD4+ T cells, causing a cascade of phenomena resulting in the instability of the gut mucosa. The effect of HIV infection on gut microbiome dysbiosis remains unresolved despite antiretroviral therapy. Here, we show the results of a longitudinal study of microbiome analysis of people living with HIV (PLWH). We contrasted the diversity and composition of the microbiome of patients with HIV at the first and second time points (baseline_case and six months later follow-up_case, respectively) with those of healthy individuals (baseline_control). We found that despite low diversity indices in the follow-up_case, the abundance of some genera was recovered but not completely, similar to baseline_control. Some genera were consistently in high abundance in PLWH. Furthermore, we found that the CD4+ T-cell count and soluble CD14 level were significantly related to high and low diversity indices, respectively. We also found that the abundance of some genera was highly correlated with clinical features, especially with antiretroviral duration. This includes genera known to be correlated with worse HIV-1 progression (Achromobacter and Stenotrophomonas) and a genus associated with gut protection (Akkermansia). The fact that a protector of the gut and genera linked to a worse progression of HIV-1 are both enriched may signify that despite the improvement of clinical features, the gut mucosa remains compromised.

The Potential of Clostridium butyricum to Preserve Gut Health, and to Mitigate Non-AIDS Comorbidities in People Living with HIV

A dramatic reduction in mortality among people living with HIV (PLWH) has been achieved during the modern antiretroviral therapy (ART) era. However, ART does not restore gut barrier function even after long-term viral suppression, allowing microbial products to enter the systemic blood circulation and induce chronic immune activation. In PLWH, a chronic state of systemic inflammation exists and persists, which increases the risk of development of inflammation-associated non-AIDS comorbidities such as metabolic disorders, cardiovascular diseases, and cancer. Clostridium butyricum is a human butyrate-producing symbiont present in the gut microbiome. Convergent evidence has demonstrated favorable effects of C. butyricum for gastrointestinal health, including maintenance of the structural and functional integrity of the gut barrier, inhibition of pathogenic bacteria within the intestine, and reduction of microbial translocation. Moreover, C. butyricum supplementation has been observed to have a positive effect on various inflammation-related diseases such as diabetes, ulcerative colitis, and cancer, which are also recognized as non-AIDS comorbidities associated with epithelial gut damage. There is currently scant published research in the literature, focusing on the influence of C. butyricum in the gut of PLWH. In this hypothesis review, we speculate the use of C. butyricum as a probiotic oral supplementation may well emerge as a potential future synergistic adjunctive strategy in PLWH, in tandem with ART, to restore and consolidate intestinal barrier integrity, repair the leaky gut, prevent microbial translocation from the gut, and reduce both gut and systemic inflammation, with the ultimate objective of decreasing the risk for development of non-AIDS comorbidities in PLWH.

The Effect of Fecal Microbiota Transplantation on Cardiometabolic Risk Factors: A Systematic Review and Meta-Analysis

PURPOSE

Cardiometabolic disease (CMD) is increasing along with its predisposing factors and adverse consequences. As gut microbiota dysbiosis is established in these patients, fecal microbiota transplantation (FMT), which alters the bacterial composition of the intestine, supposedly can help improve cardiometabolic disturbances. We conducted a systematic review and meta-analysis evaluating the impact of FMT on the cardiometabolic parameters and gut microbiota composition of patients experiencing at least one cardiometabolic issue.

METHODS

Eligible studies were searched through the PubMed, Web of Science, and Scopus databases until December 2022. The initial search results underwent duplication removal and screening until each included study was scanned for intended data. The Cochrane risk of bias tool was used to evaluate the methodologic accuracy of studies and the random effects model was used for conducting the meta-analysis.

FINDINGS

Eighteen of the original 2414 articles from the literature search were entered into the systematic review; of these, 11 were included in the meta-analysis. Insulin showed a significant decrease by 24.7 pmol/L (weighted mean difference [WMD], -24.77; 95% CI, -48.704 to -0.848) after short-term follow-up, and HDL increased by 0.1 mmol/l(WMD, 0.106; 95% CI, 0.027 to 0.184) and 0.12 mmol/l(WMD, 0.120; 95% CI, 0.003 to 0.237) in those using a capsule deliver mode and in short-term follow-up, respectively. No significant changes were seen in other lipid profiles, blood glucose, insulin resistance, or anthropometric indices. In addition, multiple studies reported gut microbiota alterations after the intervention, including an increase in butyrate-producing species.

IMPLICATIONS

Although some articles reported the beneficial effects of FMT on metabolic parameters, we failed to find a clinically significant alteration. Also, information regarding proper donors and the best method to induce FMT have not yet been sufficiently investigated, which should be considered along with means to prevent potential damages. PROSPERO identifier: CRD42022380705.

The effect of sexual behavior on HIV-1 seroconversion is mediated by the gut microbiome and proinflammatory cytokines

The association between HIV-1 seroconversion and gut dysbiosis is well documented, and its association with sexual activity is also widely recognized. However, it is not known whether the gut dysbiosis mediates the effects of high-risk sexual behavior on HIV-1 seroconversion. In this report we focused on men who engaged in high-risk sexual behavior where they had receptive anal intercourse with multiple men. We demonstrate that proinflammatory cytokines, sCD14 and sCD163, and gut microbiota mediate the effects of this high-risk sexual behavior on subsequent HIV seroconversion. We discovered changes in the gut microbial ecology, prior to seroconversion, both in terms of the composition as well as inter-relationships among the commensal species. Furthermore, these changes correlate with future HIV seroconversion. Specifically, as the number of sexual partners increased, we discovered in a "dose-response" manner, a decrease in the abundance of commensal and short-chain fatty acid-producing species, A. muciniphila, B. caccae, B. fragilis, B. uniformis, Bacteroides spp., Butyricimonas spp., and Odoribacter spp, and an increase in proinflammatory species Dehalobacterium spp. and Methanobrevibacter spp. These changes were also observed among subsequent HIV seroconverters. Interestingly, we also discovered a reduction in correlations among these commensal and short-chain fatty acid producing bacteria in a "dose-response" manner with the number of sexual partners. Our mediation analysis not only provides a conceptual model for the disease process but also provides clues for future clinical interventions that will manipulate the gut microbiota to treat high-risk subjects to prevent HIV seroconversion.

Unlocking the potential of Rosa roxburghii Tratt polyphenol: a novel approach to treating acute lung injury from a perspective of the lung-gut axis

Introduction

Acute lung injury (ALI) is a serious respiratory disease characterized by progressive respiratory failure with high morbidity and mortality. It is becoming increasingly important to develop functional foods from polyphenol-rich medicinal and dietary plants in order to prevent or alleviate ALI by regulating intestinal microflora. Rosa roxburghii Tratt polyphenol (RRTP) has significant preventive and therapeutic effects on lipopolysaccharide-induced ALI mice, but its regulatory effects on gut homeostasis in ALI mice remains unclear.

Methods

This study aims to systematically evaluate the ameliorative effects of RRTP from the perspective of "lung-gut axis" on ALI mice by intestine histopathological assessment, oxidative stress indicators detection and short-chain fatty acids (SCFAs) production, and then explore the modulatory mechanisms of RRTP on intestinal homeostasis by metabolomics and gut microbiomics of cecal contents.

Results

The results showed that RRTP can synergistically exert anti-ALI efficacy by significantly ameliorating intestinal tissue damage, inhibiting oxidative stress, increasing SCFAs in cecal contents, regulating the composition and structure of intestinal flora, increasing Akkermansia muciniphila and modulating disordered intestinal endogenous metabolites.

Discussion

This study demonstrated that RRTP has significant advantages in adjuvant therapy of ALI, and systematically clarified its comprehensive improvement mechanism from a new perspective of "lung-gut axis", which provides a breakthrough for the food and healthcare industries to develop products from botanical functional herbs and foods to prevent or alleviate ALI by regulating intestinal flora.

Akkermansia muciniphila and Alcohol-Related Liver Diseases. A Systematic Review

SCOPE

Akkermansia muciniphila (A. muciniphila) are Gram negative commensal bacteria, degrading mucin in the intestinal mucosa, modulating intestinal permeability and inflammation in the digestive tract, liver, and blood. Some components can promote the relative abundance of A. muciniphila in the gut microbiota, but lower levels of A. muciniphila are more commonly found in people with obesity, diabetes, metabolic syndromes, or inflammatory digestive diseases. Over-intake of ethanol can also induce a decrease of A. muciniphila, associated with dysregulation of microbial metabolite production, impaired intestinal permeability, induction of chronic inflammation, and production of cytokines.

METHODS AND RESULTS

Using a PRISMA search strategy, a review is performed on the bacteriological characteristics of A. muciniphila, the factors capable of modulating its relative abundance in the digestive tract and its probiotic use in alcohol-related liver diseases (alcoholic hepatitis, cirrhosis, hepatocellular carcinoma, hepatic transplantation, partial hepatectomy).

CONCLUSION

Several studies have shown that supplementation with A. muciniphila can improve ethanol-related hepatic pathologies, and highlight the interest in using this bacterial species as a probiotic.

Anti-inflammatory and intestinal microbiota modulation properties of Ganoderma lucidum β-d-glucans with different molecular weight in an ulcerative colitis model

This study systematically investigated the therapeutic effects and the corresponding mechanisms of β-D-glucans from Ganoderma lucidum (G. lucidum) with different molecular weights (Mws) on ulcerative colitis (UC). Results showed that three β-d-glucans (GLPS, GLPN and GLPW) from G. lucidum with different Mws exhibited the significant activities on the reduction of typical symptoms of UC by regulating inflammatory cytokine levels, modulating intestinal immunity, improving intestinal microbiota and metabolism of short-chain fatty acids (SCFAs) in the dextran sulfate sodium (DSS)-induced mice model. Among them, the effects of the microwave assisted degraded fraction (GLPW) mainly containing two fractions with smaller Mw (1.33 × 104 and 3.51 × 103 g/mol) on the regulation of inflammatory factors and SCFAs metabolism were found to be comparable to those of GLPN with medium Mw (3.49 × 104 g/mol), and superior to those of GLPS with large Mw (2.42 × 106 g/mol). The effect of GLPW on regulation of intestinal microbiota was even better than that of GLPN. These findings suggested that lowering Mw by means of physical degradation could improve the anti-inflammatory activities of G. lucidum β-d-glucans. The analysis of anti-inflammatory mechanism also provided a feasible and theoretical basis for potential use of degraded β-d-glucans in the prevention and treatment of UC.

Influence of HIV infection on cognition and overall intelligence in HIV-infected individuals: advances and perspectives

It is now well understood that HIV-positive individuals, even those under effective ART, tend to develop a spectrum of cognitive, motor, and/or mood conditions which are contemporarily referred to as HIV-associated neurocognitive disorder (HAND), and which is directly related to HIV-1 infection and HIV-1 replication in the central nervous system (CNS). As HAND is known to induce difficulties associated with attention, concentration, and memory, it is thus legitimate and pertinent to speculate upon the possibility that HIV infection may well influence human cognition and intelligence. We therefore propose herein to review the concept of intelligence, the concept of cells of intelligence, the influence of HIV on these particular cells, and the evidence pointing to differences in observed intelligence quotient (IQ) scores between HIV-positive and HIV-negative individuals. Additionally, cumulative research evidence continues to draw attention to the influence of the gut on human intelligence. Up to now, although it is known that HIV infection profoundly alters both the composition and diversity of the gut microbiota and the structural integrity of the gut, the influence of the gut on intelligence in the context of HIV infection remains poorly described. As such, we also provide herein a review of the different ways in which HIV may influence human intelligence via the gut-brain axis. Finally, we provide a discourse on perspectives related to HIV and human intelligence which may assist in generating more robust evidence with respect to this issue in future studies. Our aim is to provide insightful knowledge for the identification of novel areas of investigation, in order to reveal and explain some of the enigmas related to HIV infection.

Oh my gut! Is the microbial origin of neurodegenerative diseases real?

There is no cure or effective treatment for neurodegenerative protein conformational diseases (PCDs), such as Alzheimer's or Parkinson's diseases, mainly because the etiology of these diseases remains elusive. Recent data suggest that unique changes in the gut microbial composition are associated with these ailments; however, our current understanding of the bacterial role in the pathogenesis of PCDs is hindered by the complexity of the microbial communities associated with specific microbiomes, such as the gut, oral, or vaginal microbiota. The composition of these specific microbiomes is regarded as a unique fingerprint affected by factors such as infections, diet, lifestyle, and antibiotics. All of these factors also affect the severity of neurodegenerative diseases. The majority of studies that reveal microbial contribution are correlational, and various models, including worm, fly, and mouse, are being utilized to decipher the role of individual microbes that may affect disease onset and progression. Recent evidence from across model organisms and humans shows a positive correlation between the presence of gram-negative enteropathogenic bacteria and the pathogenesis of PCDs. While these correlational studies do not provide a mechanistic explanation, they do reveal contributing bacterial species and provide an important basis for further investigation. One of the lurking concerns related to the microbial contribution to PCDs is the increasing prevalence of antibiotic resistance and poor antibiotic stewardship, which ultimately select for proteotoxic bacteria, especially the gram-negative species that are known for intrinsic resistance. In this review, we summarize what is known about individual microbial contribution to PCDs and the potential impact of increasing antimicrobial resistance.

Is there a role for microbiome-based approach in common variable immunodeficiency?

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by low levels of serum immunoglobulins and increased susceptibility to infections, autoimmune disorders and cancer. CVID embraces a plethora of heterogeneous manifestations linked to complex immune dysregulation. While CVID is thought to be due to genetic defects, the exact cause of this immune disorder is unknown in the large majority of cases. Compelling evidences support a linkage between the gut microbiome and the CVID pathogenesis, therefore a potential for microbiome-based treatments to be a therapeutic pathway for this disorder. Here we discuss the potential of treating CVID patients by developing a gut microbiome-based personalized approach, including diet, prebiotics, probiotics, postbiotics and fecal microbiota transplantation. We also highlight the need for a better understanding of microbiota-host interactions in CVID patients to prime the development of improved preventive strategies and specific therapeutic targets.

Effects of Vitamin E on the Gut Microbiome in Ageing and Its Relationship with Age-Related Diseases: A Review of the Current Literature

Ageing is inevitable in all living organisms and is associated with physical deterioration, disease and eventually death. Dysbiosis, which is the alteration of the gut microbiome, occurs in individuals during ageing, and plenty of studies support that gut dysbiosis is responsible for the progression of different types of age-related diseases. The economic burden of age-linked health issues increases as ageing populations increase. Hence, an improvement in disease prevention or therapeutic approaches is urgently required. In recent years, vitamin E has garnered significant attention as a promising therapeutic approach for delaying the ageing process and potentially impeding the development of age-related disease. Nevertheless, more research is still required to understand how vitamin E affects the gut microbiome and how it relates to age-related diseases. Therefore, we gathered and summarized recent papers in this review that addressed the impact of the gut microbiome on age-related disease, the effect of vitamin E on age-related disease along with the role of vitamin E on the gut microbiome and the relationship with age-related diseases which are caused by ageing. Based on the studies reported, different bacteria brought on various age-related diseases with either increased or decreased relative abundances. Some studies have also reported the positive effects of vitamin E on the gut microbiome as beneficial bacteria and metabolites increase with vitamin E supplementation. This demonstrates how vitamin E is vital as it affects the gut microbiome positively to delay ageing and the progression of age-related diseases. The findings discussed in this review will provide a simplified yet deeper understanding for researchers studying ageing, the gut microbiome and age-related diseases, allowing them to develop new preclinical and clinical studies.

Metformin may be a viable adjunctive therapeutic option to potentially enhance immune reconstitution in HIV-positive immunological non-responders

ABSTRACT

Incomplete immune reconstitution remains a global challenge for human immunodeficiency virus (HIV) treatment in the present era of potent antiretroviral therapy (ART), especially for those individuals referred to as immunological non-responders (INRs), who exhibit dramatically low CD4 + T-cell counts despite the use of effective antiretroviral therapy, with long-term inhibition of viral replication. In this review, we provide a critical overview of the concept of ART-treated HIV-positive immunological non-response, and also explain the known mechanisms which could potentially account for the emergence of immunological non-response in some HIV-infected individuals treated with appropriate and effective ART. We found that immune cell exhaustion, combined with chronic inflammation and the HIV-associated dysbiosis syndrome, may represent strategic aspects of the immune response that may be fundamental to incomplete immune recovery. Interestingly, we noted from the literature that metformin exhibits properties and characteristics that may potentially be useful to specifically target immune cell exhaustion, chronic inflammation, and HIV-associated gut dysbiosis syndrome, mechanisms which are now recognized for their critically important complicity in HIV disease-related incomplete immune recovery. In light of evidence discussed in this review, it can be seen that metformin may be of particularly favorable use if utilized as adjunctive treatment in INRs to potentially enhance immune reconstitution. The approach described herein may represent a promising area of therapeutic intervention, aiding in significantly reducing the risk of HIV disease progression and mortality in a particularly vulnerable subgroup of HIV-positive individuals.

Sigma-1 receptor knockout disturbs gut microbiota, remodels serum metabolome, and exacerbates isoprenaline-induced heart failure

Introduction

Heart failure (HF) is usually the end stage of the continuum of various cardiovascular diseases. However, the mechanism underlying the progression and development of HF remains poorly understood. The sigma-1 receptor (Sigmar1) is a non-opioid transmembrane receptor implicated in many diseases, including HF. However, the role of Sigmar1 in HF has not been fully elucidated.

Methods

In this study, we used isoproterenol (ISO) to induce HF in wild-type (WT) and Sigmar1 knockout (Sigmar1-/-) mice. Multi-omic analysis, including microbiomics, metabolomics and transcriptomics, was employed to comprehensively evaluate the role of Sigmar1 in HF.

Results

Compared with the WT-ISO group, Sigmar1-/- aggravated ISO-induced HF, including left ventricular systolic dysfunction and ventricular remodeling. Moreover, Sigmar1-/- exacerbated ISO-induced gut microbiota dysbiosis, which was demonstrated by the lower abundance of probiotics g_Akkermansia and g_norank_f_Muribaculaceae, and higher abundance of pathogenic g_norank_f_Oscillospiraceae and Allobaculum. Furthermore, differential metabolites among WT-Control, WT-ISO and Sigmar-/--ISO groups were mainly enriched in bile secretion, tryptophan metabolism and phenylalanine metabolism, which presented a close association with microbial dysbiosis. Corresponding with the exacerbation of the microbiome, the inflammation-related NOD-like receptor signaling pathway, NF-kappa B signaling pathway and TNF signaling pathway were activated in the heart tissues.

Conclusion

Taken together, this study provides evidence that a Sigmar1 knockout disturbs the gut microbiota and remodels the serum metabolome, which may exacerbate HF by stimulating heart inflammation.

Coptis chinensis-Induced Changes in Metabolomics and Gut Microbiota in Rats

Rhizoma coptidis (CR) is traditionally used for treating gastrointestinal diseases. Wine-processed CR (wCR), zingiber-processed CR (zCR), and evodia-processed CR (eCR) are its major processed products. However, the related study of their specific mechanisms is very limited, and they need to be further clarified. The aim of this study is to compare the intervening mechanism of wCR/zCR/eCR on rats via faecal metabolomics and 16S rDNA gene sequencing analysis. First, faecal samples were collected from the control and CR/wCR/zCR/eCR groups. Then, a metabolomics analysis was performed using UHPLC-Q/TOF-MS to obtain the metabolic profile and significantly altered metabolites. The 16S rDNA gene sequencing analysis was carried out to analyze the composition of gut microbiota and screen out the significantly altered microbiota at the genus level. Finally, a pathway enrichment analysis of the significantly altered metabolites via the KEGG database and a functional prediction of relevant gut microbes based on PICRUSt2 software were performed in combination. Together with the correlation analysis between metabolites and gut microbiota, the potential intervening mechanism of wCR/zCR/eCR was explored. The results suggested that wCR played a good role in maintaining immune homeostasis, promoting glycolysis, and reducing cholesterol; zCR had a better effect on protecting the integrity of the intestinal mucus barrier, preventing gastric ulcers, and reducing body cholesterol; eCR was good at protecting the integrity of the intestinal mucus barrier and promoting glycolysis. This study scientifically elucidated the intervening mechanism of wCR/zCR/eCR from the perspective of faecal metabolites and gut microbiota, providing a new insight into the processing mechanism research of Chinese herbs.

Therapeutically targeting the consequences of HIV-1-associated gastrointestinal dysbiosis: Implications for neurocognitive and affective alterations

Approximately 50 % of the individuals living with human immunodeficiency virus type 1 (HIV-1) are plagued by debilitating neurocognitive impairments (NCI) and/or affective alterations. Sizeable alterations in the composition of the gut microbiome, or gastrointestinal dysbiosis, may underlie, at least in part, the NCI, apathy, and/or depression observed in this population. Herein, two interrelated aims will be critically addressed, including: 1) the evidence for, and functional implications of, gastrointestinal microbiome dysbiosis in HIV-1 seropositive individuals; and 2) the potential for therapeutically targeting the consequences of this dysbiosis for the treatment of HIV-1-associated NCI and affective alterations. First, gastrointestinal microbiome dysbiosis in HIV-1 seropositive individuals is characterized by decreased alpha (α) diversity, a decreased relative abundance of bacterial species belonging to the Bacteroidetes phylum, and geographic-specific alterations in Bacillota (formerly Firmicutes) spp. Fundamentally, changes in the relative abundance of Bacteroidetes and Bacillota spp. may underlie, at least in part, the deficits in γ-aminobutyric acid and serotonin neurotransmission, as well as prominent synaptodendritic dysfunction, observed in this population. Second, there is compelling evidence for the therapeutic utility of targeting synaptodendritic dysfunction as a method to enhance neurocognitive function and improve motivational dysregulation in HIV-1. Further research is needed to determine whether the therapeutics enhancing synaptic efficacy exert their effects by altering the gut microbiome. Taken together, understanding gastrointestinal microbiome dysbiosis resulting from chronic HIV-1 viral protein exposure may afford insight into the mechanisms underlying HIV-1-associated neurocognitive and/or affective alterations; mechanisms which can be subsequently targeted via novel therapeutics.

Health benefits of anthocyanin-containing foods, beverages, and supplements have unpredictable relation to gastrointestinal microbiota: A systematic review and meta-analysis of random clinical trials

Anthocyanins are a type of natural pigment that has numerous health benefits. In recent years, the interaction of anthocyanins with gastrointestinal (GI) microbiota has been presented as a viable paradigm for explaining anthocyanin activities. The current study performed a systematic review and meta-analysis to determine the potential modulation of GI microbiota by anthocyanins in human health improvement. Clinical trials were retrieved from PubMed, Cochrane, Web of Knowledge, China Biology Medicine, China National Knowledge Infrastructure, and ClinicalTrials.gov with no language restrictions. Eight clinical trials (252 participants) were selected from the 1121 identified studies and the relative phylum abundance extracted from the trials was analyzed using a random-effects model. Based on the analysis, anthocyanins had no effect on the relative abundance of Firmicutes (standard mean difference [SMD]: -0.46 [-1.25 to 0.34], P = .26), Proteobacteria (SMD, -0.32 [-0.73 to 0.09], P = .13), nor Actinobacteria (SMD, -0.19 [-0.50 to 0.12], P = 0.24), but influenced the abundance of Bacteroidetes (SMD, 0.84 [0.17 to 1.52], P = .01) when compared with placebo/control. No significant influence on the relative abundance was detected when the data were analyzed following the "posttreatment vs. pretreatment" strategy. Our preliminary analysis revealed that the effects of anthocyanins on human GI microbiota vary between studies and individuals, and at the current stage, the clinical trials regarding the effects of anthocyanin interventions on human GI microbiota are lacking. More trials with larger sample sizes are needed to promote the clinical application of anthocyanins.

Dietary Supplementation with a Cocoa-Carob Blend Modulates Gut Microbiota and Prevents Intestinal Oxidative Stress and Barrier Dysfunction in Zucker Diabetic Rats

We have recently developed a cocoa-carob blend (CCB) rich in polyphenols with antidiabetic properties. In this study, we investigated whether its benefits could be related to gut health and gut microbiota (GM) composition and the likely phenolic metabolites involved. Zucker diabetic fatty rats were fed on a standard or a CCB-rich diet for 12 weeks. Intestinal barrier structure and oxidative and inflammatory biomarkers were analyzed in colonic samples. GM composition and phenolic metabolites were evaluated from feces. The results show that CCB improved mucin and tight-junction proteins and counteracted gut oxidative stress and inflammation by regulating sirtuin-1 and nuclear factor erythroid 2-related factor 2 (Nrf2) levels. CCB also modulated the composition of the GM, showing increases in Akkermansia and Bacteroides and decreases in Ruminococcus genera. Correlation analysis strengthened the associations between these genera and improved pathological variables in diabetic animals. Moreover, 12 phenolic metabolites were identified in CCB feces, being2,3-dihydroxybenzoic and 3,4,5-trihydroxybenzoic acids significantly associated with increased levels of Akkermansia and Oscillospira genera. Our findings support the potential use of CCB to prevent intestinal damage and dysbiosis in T2D, which would help to delay the progression of this pathology.

Ambient particulate air pollution and the intestinal microbiome; a systematic review of epidemiological, in vivo and, in vitro studies

A healthy indigenous intestinal microbiome is indispensable for intra- and extra-intestinal human health. Since well-established factors such as diet and antibiotic use only explain 16 % of the inter-individual variation in gut microbiome composition, recent studies have focused on the association between ambient particulate air pollution and the intestinal microbiome. We systematically summarize and discuss all evidence concerning the effect of particulate air pollution on intestinal bacterial diversity indices, specific bacterial taxa, and potential underlying intestinal mechanisms. To this end, all possibly relevant publications published between February 1982 and January 2023 were screened, and eventually, 48 articles were included. The vast majority (n = 35) of these studies were animal studies. The exposure periods investigated in the human epidemiological studies (n = 12) ranged from infancy through elderly. This systematic review found that intestinal microbiome diversity indices were generally negatively associated with particulate air pollution in epidemiological studies, with an increase in taxa belonging to Bacteroidetes (two studies), Deferribacterota (one study), and Proteobacteria (four studies), a decrease in taxa belonging to Verrucomicrobiota (one study), and no consensus for taxa belonging to Actinobacteria (six studies) and Firmicutes (seven studies). There was no unequivocal effect of ambient particulate air pollution exposure on bacterial indices and taxa in animal studies. Only one study in humans examined a possible underlying mechanism; yet, the included in vitro and animal studies depicted higher gut damage, inflammation, oxidative stress, and permeability in exposed versus unexposed animals. Overall, the population-based studies showed a dose-related continuum of short- and long-term ambient particulate air pollution exposure on lower gut diversity and shifts in taxa over the entire life course.

Exposing new taxonomic variation with inflammation - a murine model-specific genome database for gut microbiome researchers

BACKGROUND

The murine CBA/J mouse model widely supports immunology and enteric pathogen research. This model has illuminated Salmonella interactions with the gut microbiome since pathogen proliferation does not require disruptive pretreatment of the native microbiota, nor does it become systemic, thereby representing an analog to gastroenteritis disease progression in humans. Despite the value to broad research communities, microbiota in CBA/J mice are not represented in current murine microbiome genome catalogs.

RESULTS

Here we present the first microbial and viral genomic catalog of the CBA/J murine gut microbiome. Using fecal microbial communities from untreated and Salmonella-infected, highly inflamed mice, we performed genomic reconstruction to determine the impacts on gut microbiome membership and functional potential. From high depth whole community sequencing (~ 42.4 Gbps/sample), we reconstructed 2281 bacterial and 4516 viral draft genomes. Salmonella challenge significantly altered gut membership in CBA/J mice, revealing 30 genera and 98 species that were conditionally rare and unsampled in non-inflamed mice. Additionally, inflamed communities were depleted in microbial genes that modulate host anti-inflammatory pathways and enriched in genes for respiratory energy generation. Our findings suggest decreases in butyrate concentrations during Salmonella infection corresponded to reductions in the relative abundance in members of the Alistipes. Strain-level comparison of CBA/J microbial genomes to prominent murine gut microbiome databases identified newly sampled lineages in this resource, while comparisons to human gut microbiomes extended the host relevance of dominant CBA/J inflammation-resistant strains.

CONCLUSIONS

This CBA/J microbiome database provides the first genomic sampling of relevant, uncultivated microorganisms within the gut from this widely used laboratory model. Using this resource, we curated a functional, strain-resolved view on how Salmonella remodels intact murine gut communities, advancing pathobiome understanding beyond inferences from prior amplicon-based approaches. Salmonella-induced inflammation suppressed Alistipes and other dominant members, while rarer commensals like Lactobacillus and Enterococcus endure. The rare and novel species sampled across this inflammation gradient advance the utility of this microbiome resource to benefit the broad research needs of the CBA/J scientific community, and those using murine models for understanding the impact of inflammation on the gut microbiome more generally. Video Abstract.

Translocation of bacterial LPS is associated with self-reported cognitive abilities in men living with HIV receiving antiretroviral therapy

BACKGROUND

Gut damage allows translocation of bacterial lipopolysaccharide (LPS) and fungal β-D-glucan (BDG) into the blood. This microbial translocation contributes to systemic inflammation and risk of non-AIDS comorbidities in people living with HIV, including those receiving antiretroviral therapy (ART). We assessed whether markers of gut damage and microbial translocation were associated with cognition in ART-treated PLWH.

METHODS

Eighty ART-treated men living with HIV from the Positive Brain Health Now Canadian cohort were included. Brief cognitive ability measure (B-CAM) and 20-item patient deficit questionnaire (PDQ) were administered to all participants. Three groups were selected based on their B-CAM levels. We excluded participants who received proton pump inhibitors or antiacids in the past 3 months. Cannabis users were also excluded. Plasma levels of intestinal fatty acid binding protein (I-FABP), regenerating islet-derived protein 3 α (REG3α), and lipopolysaccharides (LPS = were quantified by ELISA, while 1-3-β-D-glucan BDG) levels were assessed using the Fungitell assay. Univariable, multivariable, and splines analyses were performed.

RESULTS

Plasma levels of I-FABP, REG3α, LPS and BDG were not different between groups of low, intermediate and high B-CAM levels. However, LPS and REG3α levels were higher in participants with PDQ higher than the median. Multivariable analyses showed that LPS association with PDQ, but not B-CAM, was independent of age and level of education. I-FABP, REG3α, and BDG levels were not associated with B-CAM nor PDQ levels in multivariable analyses.

CONCLUSION

In this well characterized cohort of ART-treated men living with HIV, bacterial but not fungal translocation was associated with presence of cognitive difficulties. These results need replication in larger samples.

Probiotics for the treatment of depression and its comorbidities: A systemic review

Depression is one of the most common psychiatric conditions, characterized by significant and persistent depressed mood and diminished interest, and often coexists with various comorbidities. The underlying mechanism of depression remain elusive, evidenced by the lack of an appreciate therapy. Recent abundant clinical trials and animal studies support the new notion that the gut microbiota has emerged as a novel actor in the pathophysiology of depression, which partakes in bidirectional communication between the gut and the brain through the neuroendocrine, nervous, and immune signaling pathways, collectively known as the microbiota-gut-brain (MGB) axis. Alterations in the gut microbiota can trigger the changes in neurotransmitters, neuroinflammation, and behaviors. With the transition of human microbiome research from studying associations to investigating mechanistic causality, the MGB axis has emerged as a novel therapeutic target in depression and its comorbidities. These novel insights have fueled idea that targeting on the gut microbiota may open new windows for efficient treatment of depression and its comorbidities. Probiotics, live beneficial microorganisms, can be used to modulate gut dysbiosis into a new eubiosis and modify the occurrence and development of depression and its comorbidities. In present review, we summarize recent findings regarding the MGB axis in depression and discuss the potential therapeutic effects of probiotics on depression and its comorbidities.

Enteropathy and gut dysbiosis as obstacles to achieve immune recovery in undetectable people with HIV: a clinical view of evidence, successes, and projections

Immune performance following antiretroviral therapy initiation varies among patients. Despite achieving viral undetectability, a subgroup of patients fails to restore CD4+ T-cell counts during follow-up, which exposes them to non-AIDS defining comorbidities and increased mortality. Unfortunately, its mechanisms are incompletely understood, and no specific treatment is available. In this review, we address some of the pathophysiological aspects of the poor immune response from a translational perspective, with emphasis in the interaction between gut microbiome, intestinal epithelial dysfunction, and immune system, and we also discuss some studies attempting to improve immune performance by intervening in this vicious cycle.

Akkermansia muciniphila as a Next-Generation Probiotic in Modulating Human Metabolic Homeostasis and Disease Progression: A Role Mediated by Gut-Liver-Brain Axes?

Appreciation of the importance of Akkermansia muciniphila is growing, and it is becoming increasingly relevant to identify preventive and/or therapeutic solutions targeting gut-liver-brain axes for multiple diseases via Akkermansia muciniphila. In recent years, Akkermansia muciniphila and its components such as outer membrane proteins and extracellular vesicles have been known to ameliorate host metabolic health and intestinal homeostasis. However, the impacts of Akkermansia muciniphila on host health and disease are complex, as both potentially beneficial and adverse effects are mediated by Akkermansia muciniphila and its derivatives, and in some cases, these effects are dependent upon the host physiology microenvironment and the forms, genotypes, and strain sources of Akkermansia muciniphila. Therefore, this review aims to summarize the current knowledge of how Akkermansia muciniphila interacts with the host and influences host metabolic homeostasis and disease progression. Details of Akkermansia muciniphila will be discussed including its biological and genetic characteristics; biological functions including anti-obesity, anti-diabetes, anti-metabolic-syndrome, anti-inflammation, anti-aging, anti-neurodegenerative disease, and anti-cancer therapy functions; and strategies to elevate its abundance. Key events will be referred to in some specific disease states, and this knowledge should facilitate the identification of Akkermansia muciniphila-based probiotic therapy targeting multiple diseases via gut-liver-brain axes.

Influence of letermovir treatment on gut inflammation in people living with HIV on antiretroviral therapy: protocol of the open-label controlled randomised CIAO study

INTRODUCTION

Chronic cytomegalovirus (CMV) infection is very frequent in people living with HIV (PLWH). High anti-CMV IgG titres, which may be linked to transient CMV replication, have been associated with earlier mortality, CD8 T-cell expansion, lower CD4/CD8 ratio and increased T-cell senescence. We previously showed that anti-CMV IgG titres correlated with gut permeability in PLWH on antiretroviral therapy (ART), which was associated with microbial translocation, systemic inflammation and non-infectious/non-AIDS comorbidities. Letermovir, a novel anti-CMV drug with a good safety profile, was recently approved for anti-CMV prophylaxis in allogeneic haematopoietic stem cell transplant recipients. A drastic and selective reduction of both low-grade replication and clinically significant CMV infections, combined with an improved immune reconstitution have been reported. In vitro, letermovir prevented CMV-induced epithelial disruption in intestinal tissues. Based on these findings, we aim to assess whether letermovir could inhibit CMV subclinical replication in CMV-seropositive PLWH receiving ART and, in turn, decrease CMV-associated gut damage and inflammation.

METHOD AND ANALYSIS

We will conduct a multi-centre, open-label, randomised, controlled clinical trial, including a total of 60 CMV-seropositive ART-treated PLWH for at least 3 years, with a viral load <50 copies/mL and CD4+ count >400 cells/µL. Forty participants will be randomised to receive letermovir for 14 weeks and 20 participants will receive standard of care (ART) alone. Plasma, pheripheral blood mononuclear cells (PBMCs), and stool samples will be collected. Colon biopsies will be collected in an optional substudy. We will assess the effect of letermovir on gut damage, microbial translocation, inflammation and HIV reservoir size.

ETHICS AND DISSEMINATION

The study was approved by Health Canada and the Research Ethics Boards of the McGill University Health Centre (MUHC-REB, protocol number: MP37-2022-8295). Results will be made available through publications in open access peer-reviewed journals and through the CIHR/CTN website.

TRIAL REGISTRATION NUMBER

NCT05362916.

Candida albicans can foster gut dysbiosis and systemic inflammation during HIV infection

Candida albicans (C. albicans) is a ubiquitous fungal commensal component of the human microbiota, and under certain circumstances, such as during an immunocompromised state, it may initiate different types of infection. Moreover, C. albicans continuously and reciprocally interacts with the host immune system as well as with other elements of the gut microbiota, thus contributing significantly to both gut homeostasis and host immunity. People living with HIV (PLWH), including those receiving antiretroviral therapy, are characterized by a depletion of CD4 + T-cells and dysbiosis in their gut. C. albicans colonization is frequent in PLWH, causing both a high prevalence and high morbidity. Gut barrier damage and elevated levels of microbial translocation are also fairly common in this population. Herein, we take a closer look at the reciprocity among C. albicans, gut microbiota, HIV, and the host immune system, thus throwing some light on this complex interplay.

Case Report: The effect of intravenous and oral antibiotics on the gut microbiome and breath volatile organic compounds over one year

BACKGROUND

Antimicrobial resistance (AMR) is a global concern and better understanding of the gut microbiome, a known 'amplifier' of AMR, may allow future clinicians to tailor therapy to minimise this risk and offer a personalised medicine approach. To examine the gut microbiome, patients are required to provide faecal samples; more convenient and cheaper solutions need to be found.

METHODS

As part of a pilot study looking at how routes of administration affect the gut microbiome in NHS patients undergoing routine clinical management for infections, we hypothesised that effects on the gut microbiome varied with the route and metabolism of antibiotic used, and these changes may be reflected in breath metabolites. We present a case report of a patient with an unusual clinical history, alongside breath metabolite and gut microbiome data taken before, during and after antibiotic therapy over a period of one year.

RESULTS

We noted a shift in the dominant Bacteroides strain in the patient's gut microbiome between pre- and post-therapy samples, along with an alteration in the composition of breath metabolites.

CONCLUSIONS

This study provides a framework for similar future work and highlights the need for further research on the relationships between changes in microbial gut communities and antimicrobial exposure, patient clinical status, and the metabolites of human breath.

Akkermansia muciniphila and Faecalibacterium prausnitzii in Immune-Related Diseases

Probiotics and synbiotics are used to treat chronic illnesses due to their roles in immune system modulation and anti-inflammatory response. They have been shown to reduce inflammation in a number of immune-related disorders, including systemic lupus erythematosus (SLE), human immunodeficiency virus (HIV), and chronic inflammatory skin conditions such as psoriasis and atopic dermatitis (AD). Akkermansia muciniphila (A. muciniphila) and Faecalibacterium prausnitzii (F. prausnitzii) are two different types of bacteria that play a significant part in this function. It has been established that Akkermansia and Faecalibacterium are abundant in normal populations and have protective benefits on digestive health while also enhancing the immune system, metabolism, and gut barrier of the host. They have the potential to be a therapeutic target in diseases connected to the microbiota, such as immunological disorders and cancer immunotherapy. There has not been a review of the anti-inflammatory effects of Akkermansia and Faecalibacterium, particularly in immunological diseases. In this review, we highlight the most recent scientific findings regarding A. muciniphila and F. prausnitzii as two significant gut microbiota for microbiome alterations and seek to provide cutting-edge insight in terms of microbiome-targeted therapies as promising preventive and therapeutic tools in immune-related diseases and cancer immunotherapy.

Amoxicillin impact on pathophysiology induced by short term high salt diet in mice

Current evidence emerging from both human and animal models confirms that high-salt diet consumption over a period modulates the gut ecology and subsequently accelerates the development of the pathophysiology of many metabolic diseases. The knowledge of short-term intake of a high-salt diet (HSD) on gut microbiota and their role in the progression of metabolic pathogenesis and the consequence of a typical course of common antibiotics in this condition has yet not been investigated. The present study elicited this knowledge gap by studying how the gut microbiota profile changes in mice receiving HSD for a short period followed by Amoxicillin treatment on these mice in the last week to mimic a typical treatment course of antibiotics. In this study, we provided a standard chow diet (CD) and HSD for 3 weeks, and a subset of these mice on both diets received antibiotic therapy with Amoxicillin in the 3rd week. We measured the body weight of mice for 3 weeks. After 21 days, all animals were euthanised and subjected to a thorough examination for haemato-biochemical, histopathological, and 16S rRNA sequencing, followed by bioinformatics analysis to determine any changes in gut microbiota ecology. HSD exposure in mice for short duration even leads to a significant difference in the gut ecology with enrichment of specific gut microbiota crucially linked to developing the pathophysiological features of metabolic disease-related inflammation. In addition, HSD treatment showed a negative impact on haemato-biochemical parameters. However, Amoxicillin treatment in HSD-fed mice restored the blood-biochemical markers near to control values and reshaped gut microbiota known for improving the pathophysiological attributes of metabolic disease related inflammation. This study also observed minimal and insignificant pathological changes in the heart, liver, and kidney in HSD-fed mice.

Gut bacterial profiles in Parkinson's disease: A systematic review

INTRODUCTION

Recent advances have highlighted the relationships between gut dysbiosis and Parkinson's disease (PD). Microbiota transplantation from PD patients to mice can induce increased alpha-synuclein-mediated motor deficits. Human studies have identified differences in the gut microbiota of PD patients compared to healthy controls. We undertook a systematic review to evaluate the available evidence for the involvement of gut bacteria in the etiology of PD.

METHODS

The PubMed databank, the China National Knowledge Infrastructure databank, and Wanfang Data were searched from inception until June 2021 to identify human case-control studies that investigated relationships between PD and microbiota quantified from feces. We evaluated the resulting studies focusing on bacterial taxa that were different between PD patients and healthy controls.

RESULTS

Twenty-six studies were found in which 53 microbial families and 98 genera exhibited differences between patients with PD and healthy controls. The genera identified by more than two studies as increased in PD were Bifidobacterium, Alistipes, Christensenella, Enterococcus, Oscillospira, Bilophila, Desulfovibrio, Escherichia/Shigella, and Akkermansia, while Prevotella, Blautia, Faecalibacterium, Fusicatenibacter, and Haemophilus had three or more reports of being lower in PD patients. More than one report demonstrated that Bacteroides, Odoribacter, Parabacteroides, Butyricicoccus, Butyrivibrio, Clostridium, Coprococcus, Lachnospira, Lactobacillus, Megasphaera, Phascolarctobacterium, Roseburia, Ruminococcus, Streptococcus, and Klebsiella were altered in both directions.

CONCLUSION

Our review shows that the involvement of the gut microbiome in the etiology of PD may involve alterations of short-chain fatty acids (SCFAs)-producing bacteria and an increase in putative gut pathobionts. SCFAs-producing bacteria may vary above or below an "optimal range," causing imbalances. Considering that Bifidobacterium, Lactobacillus, and Akkermansia are beneficial for human health, increased Bifidobacterium and Lactobacillus in the PD gut microbiome may be associated with PD medications, especially COMT inhibitors, while a high level of Akkermansia may be associated with aging.

Gut dysbiosis and inflammatory blood markers precede HIV with limited changes after early seroconversion

BACKGROUND

Alterations in the gut microbiome have been associated with HIV infection, but the relative impact of HIV versus other factors on the gut microbiome has been difficult to determine in cross-sectional studies.

METHODS

To address this, we examined the gut microbiome, serum metabolome, and cytokines longitudinally within 27 individuals before and during acute HIV using samples collected from several ongoing cohort studies. Matched control participants (n=28) from the same cohort studies without HIV but at similar behavioral risk were used for comparison.

FINDINGS

We identified few changes in the microbiome during acute HIV infection, but did find alterations in serum metabolites involving secondary bile acid (lithocholate sulfate, glycocholenate sulfate) and amino acid metabolism (3-methyl-2-oxovalerate, serine, cysteine, N-acetylputrescine). Greater microbiome differences, including decreased Bacteroides spp and increased Megasphaera elsdenii, were seen when comparing pre-HIV infection visits to matched at-risk controls. Those who acquired HIV also had elevated inflammatory cytokines (TNF-α, B cell activating factor, IL-8) and bioactive lipids (palmitoyl-sphingosine-phosphoethanolamide and glycerophosphoinositol) prior to HIV acquisition compared to matched controls.

INTERPRETATION

Longitudinal sampling identified pre-existing microbiome differences in participants with acute HIV compared to matched control participants observed over the same period. These data highlight the importance of increasing understanding of the role of the microbiome in HIV susceptibility.

FUNDING

This work was supported by NIH/NIAID (K08AI124979; P30AI117943), NIH/NIDA (U01DA036267; U01DA036939; U01DA036926; U24DA044554), and NIH/NIMH (P30MH058107; R34MH105272).

Phase I trial of Bermekimab with nanoliposomal irinotecan and 5-fluorouracil/folinic acid in advanced pancreatic ductal adenocarcinoma

In this phase I dose-escalation trial, we assess the maximum tolerated dose (MTD) of Bermekimab in combination with Nanoliposomal Irinotecan (Nal-Iri) and 5-Fluorouracil/Folinic Acid (5-FU/FA). Secondarily, we investigate effects on weight, lean body mass, quality-of-life, the gut microbiome composition, inflammatory biomarkers, progression-free survival, and overall survival. This was a single-arm, open-label adaptive Bayesian dose-escalation study of Bermekimab combined with Nal-Iri and 5FU/FA in patients with advanced or locally advanced PDAC who failed gemcitabine-based chemotherapy. 22 patients enrolled between 2017 and 2019. 3 of 21 patients experienced dose-limiting toxicities attributable to the chemotherapy backbone. 58% (10/17) of patients exhibited weight stability. Physical performance status was preserved among all subjects. Patients reported improvements in quality-of-life metrics via QLQ-PAN26 questioner (-3.6, p = 0.18) and functional well-being (1.78, p = 0.02). Subjects exhibited a decrease in inflammatory cytokines, notably, vascular endothelial growth factor (-0.86, p = 0.017) with Bermekimab. Bermekimab treatment was associated with an increased abundance of gut health-promoting bacterial genera Akkermansia, with 3.82 Log2-fold change from baseline. In sum, Bermekimab is safe to be used in conjunction with Nal-Iri and 5-FU/FA chemotherapy. This benign toxicological profile warrants further Phase I/II investigation of Bermekimab in combinatorial strategies, and the impact of anti-IL-1α antibodies on the gut microbiome.Clinical trials registration: NCT03207724 05/07/2017.

Akkermansia muciniphila phospholipid induces homeostatic immune responses

Multiple studies have established associations between human gut bacteria and host physiology, but determining the molecular mechanisms underlying these associations has been challenging1-3. Akkermansia muciniphila has been robustly associated with positive systemic effects on host metabolism, favourable outcomes to checkpoint blockade in cancer immunotherapy and homeostatic immunity4-7. Here we report the identification of a lipid from A. muciniphila's cell membrane that recapitulates the immunomodulatory activity of A. muciniphila in cell-based assays8. The isolated immunogen, a diacyl phosphatidylethanolamine with two branched chains (a15:0-i15:0 PE), was characterized through both spectroscopic analysis and chemical synthesis. The immunogenic activity of a15:0-i15:0 PE has a highly restricted structure-activity relationship, and its immune signalling requires an unexpected toll-like receptor TLR2-TLR1 heterodimer9,10. Certain features of the phospholipid's activity are worth noting: it is significantly less potent than known natural and synthetic TLR2 agonists; it preferentially induces some inflammatory cytokines but not others; and, at low doses (1% of EC50) it resets activation thresholds and responses for immune signalling. Identifying both the molecule and an equipotent synthetic analogue, its non-canonical TLR2-TLR1 signalling pathway, its immunomodulatory selectivity and its low-dose immunoregulatory effects provide a molecular mechanism for a model of A. muciniphila's ability to set immunological tone and its varied roles in health and disease.

Gut Microbiota of Obese Children Influences Inflammatory Mucosal Immune Pathways in the Respiratory Tract to Influenza Virus Infection: Optimization of an Ideal Duration of Microbial Colonization in a Gnotobiotic Pig Model

The impact of obesity on the human microbiota, immune maturation, and influenza virus infection has not been yet established in natural host animal models of influenza. In this study, gnotobiotic (Gn) pigs were colonized with human fecal microbiota (HFM) of obese (oHFM) or healthy lean (hHFM) children and infected at different periods (2-, 3-, and 5-weeks post-transplantation) using a zoonotic influenza virus strain. The infected oHFM pigs were characterized by lower levels of Firmicutes (Lactococcus, Lactobacillus, Turicibacter, and Streptococcus) and Actinobacteria (Bifidobacterium), which was associated with higher levels of Proteobacteria (Klebsiella), Bacteroidetes, and Verrucomicrobia (Akkermansia) compared with the infected hHFM group (P < 0.01). Furthermore, these genera significantly correlated with the expression of immune effectors, immune regulators, and inflammatory mediators, and displayed opposite trends between oHFM and hHFM groups (P < 0.01). The lymphoid and myeloid immune cell frequencies were differently modulated by the oHFM and hHFM colonization, especially apparent in the 5-weeks HFM colonized piglets. In addition, oHFM group had higher pro-inflammatory cytokines (IL-6, IL-12, TNF-α, and IFNγ) gene expression in the respiratory tract compared with the hHFM colonized pigs was detected. In conclusion, pigs colonized for longer duration, established oHFM increased the immune maturation favoring the activation of inflammatory mediators, however, the influenza virus load remained comparable with the hHFM group. Further, a longer duration of microbial colonization (5 weeks) may be required to reveal the impact of microbiome on the host immune maturation and susceptibility to influenza virus infection in the humanized Gn pig model. IMPORTANCE The diversity of gut microbiome of obese people differs markedly from that of lean healthy individuals which, in turn, influences the severity of inflammatory diseases because of differential maturation of immune system. The mouse model provides crucial insights into the mechanism(s) regulating the immune systems mediated by the gut microbiota but its applicability to humans is questionable because immune cells in mice are poorly activated in microbiota humanized mice. Several important strains of Bifidobacterium, Lactobacillus, and Clostridium fails to colonize the murine gut. Thus, understanding the role of certain important commensal gut bacterial species influences upon health and disease, a suitable large animal model like pig that supports the growth and colonization of most of the important human gut bacteria and possess comparable immunology and physiology to humans is beneficial to improve health.

The Gut Microbiota and Vascular Aging: A State-of-the-Art and Systematic Review of the Literature

The gut microbiota is a critical regulator of human physiology, deleterious changes to its composition and function (dysbiosis) have been linked to the development and progression of cardiovascular diseases. Vascular ageing (VA) is a process of progressive stiffening of the arterial tree associated with arterial wall remodeling, which can precede hypertension and organ damage, and is associated with cardiovascular risk. Arterial stiffness has become the preferred marker of VA. In our systematic review, we found an association between gut microbiota composition and arterial stiffness, with two patterns, in most animal and human studies: a direct correlation between arterial stiffness and abundances of bacteria associated with altered gut permeability and inflammation; an inverse relationship between arterial stiffness, microbiota diversity, and abundances of bacteria associated with most fit microbiota composition. Interventional studies were able to show a stable link between microbiota modification and arterial stiffness only in animals. None of the human interventional trials was able to demonstrate this relationship, and very few adjusted the analyses for determinants of arterial stiffness. We observed a lack of large randomized interventional trials in humans that test the role of gut microbiota modifications on arterial stiffness, and take into account BP and hemodynamic alterations.

The Untapped Potential of Ginsenosides and American Ginseng Berry in Promoting Mental Health via the Gut-Brain Axis

Despite the popularity of the ginseng (Panax) root in health research and on the market, the ginseng berry’s potential remains relatively unexplored. Implementing ginseng berry cultivations and designing berry-derived products could improve the accessibility to mental health-promoting nutraceuticals. Indeed, the berry could have a higher concentration of neuroprotective and antidepressant compounds than the root, which has already been the subject of research demonstrating its efficacy in the context of neuroprotection and mental health. In this review, data on the berry’s application in supporting mental health via the gut–brain axis is compiled and discussed.

Case Report: The effect of intravenous and oral antibiotics on the gut microbiome and breath volatile organic compounds over one year

BACKGROUND

Antimicrobial resistance (AMR) is a global concern and better understanding of the gut microbiome, a known 'amplifier' of AMR, may allow future clinicians to tailor therapy to minimise this risk and offer a personalised medicine approach. To examine the gut microbiome, patients are required to provide faecal samples; more convenient and cheaper solutions need to be found.

METHODS

As part of a pilot study looking at how routes of administration affect the gut microbiome in NHS patients undergoing routine clinical management for infections, we hypothesised that effects on the gut microbiome varied with the route and metabolism of antibiotic used, and these changes may be reflected in breath metabolites. We present a case report of a patient with an unusual clinical history, alongside breath metabolite and gut microbiome data taken before, during and after antibiotic therapy over a period of one year.

RESULTS

We noted a shift in the dominant Bacteroides strain in the patient's gut microbiome between pre- and post-therapy samples, along with an alteration in the composition of breath metabolites.

CONCLUSIONS

This study provides a framework for similar future work and highlights the need for further research on the relationships between changes in microbial gut communities and antimicrobial exposure, patient clinical status, and the metabolites of human breath.

Integrase Inhibitors Partially Restore Bacterial Translocation, Inflammation and Gut Permeability Induced by HIV Infection: Impact on Gut Microbiota

Introduction

Human immunodeficiency virus (HIV) infection can be considered a chronic disease thanks to the extended use of antiretroviral treatment (ART). In this context, low-grade chronic inflammation related to gut microbiota (GM) dysbiosis and bacterial translocation (BT) among other factors has been observed despite the use of ART. In addition, different ART regimens have demonstrated differential impacts on GM. However, the role of novel integrase strand transfer inhibitors (INSTIs) has not been investigated yet. The aim of this study was to analyse the effects of INSTIs in first-line of treatment on markers of BT, inflammation, cardiovascular risk, gut permeability and GM composition and derived short-chain fatty acids.

Methods

Twenty-six non-HIV-infected volunteers and 30 HIV-infected patients (15 naïve and 15 under INSTIs regimen) were recruited. Blood samples were extracted to analyse biochemical parameters and markers of BT, inflammation, cardiovascular risk, gut permeability and bacterial metabolism. GM composition was analysed using 16S rRNA gene sequencing.

Results

Our results showed that HIV infection increased BT, inflammation, cardiovascular risk and gut permeability, whereas INSTIs counteracted these effects. Regarding GM, the reduction in bacterial richness induced by HIV infection was restored by INSTIs. Beta diversity revealed that HIV-infected people were separated from the control group independently of treatment.

Conclusions

Current antiretroviral regimens based on INSTIs are able to reverse the impact of HIV infection on BT, systemic inflammation, gut permeability and bacterial diversity/richness, reaching similar levels to those observed in an uninfected/control population. These results suggest a protective role of INSTIs in disease progression, subsequent immune activation and in the development of future age-related complications such as cardiovascular events.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-022-00654-4.

Visceral sensitivity modulation by faecal microbiota transplantation: the active role of gut bacteria in pain persistence

ABSTRACT

Recent findings linked gastrointestinal disorders characterized by abdominal pain to gut microbiota composition. The present work aimed to evaluate the power of gut microbiota as a visceral pain modulator and, consequently, the relevance of its manipulation as a therapeutic option in reversing postinflammatory visceral pain persistence. Colitis was induced in mice by intrarectally injecting 2,4-dinitrobenzenesulfonic acid (DNBS). The effect of faecal microbiota transplantation from viscerally hypersensitive DNBS-treated and naive donors was evaluated in control rats after an antibiotic-mediated microbiota depletion. Faecal microbiota transplantation from DNBS donors induced a long-lasting visceral hypersensitivity in control rats. Pain threshold trend correlated with major modifications in the composition of gut microbiota and short chain fatty acids. By contrast, no significant alterations of colon histology, permeability, and monoamines levels were detected. Finally, by manipulating the gut microbiota of DNBS-treated animals, a counteraction of persistent visceral pain was achieved. The present results provide novel insights into the relationship between intestinal microbiota and visceral hypersensitivity, highlighting the therapeutic potential of microbiota-targeted interventions.

Maternal breast milk microbiota and immune markers in relation to subsequent development of celiac disease in offspring

The potential impact of the composition of maternal breast milk is poorly known in children who develop celiac disease (CD). The aim of our study was to compare the microbiota composition and the concentrations of immune markers in breast milk from mothers whose offspring carried the genetic predisposition to CD, and whether they did or did not develop CD during follow-up for the first 3 years of life. Maternal breast milk samples [CD children (n = 6) and healthy children (n = 18)] were collected 3 months after delivery. Enzyme-linked immunosorbent assays were used to measure TGF-β1, TGF-β2, sIgA, MFG-E8 and sCD14. For microbiota analysis, next generation (Illumina) sequencing, real-time PCR and denaturing gradient gel electrophoresis were used. Phylotype abundance and the Shannon ‘H’ diversity index were significantly higher in breast milk samples in the CD group. There was higher prevalence of the phyla Bacteroidetes and Fusobacteria, the classes Clostridia and Fusobacteriia, and the genera Leptotrichia, Anaerococcus, Sphingomonas, Actynomyces and Akkermansia in the CD group. The immunological markers were differently associated with some Gram-negative bacterial genera and species (Chryseobacterium, Sphingobium) as well as Gram-positive species (Lactobacillusreuteri, Bifidobacteriumanimalis). In conclusion, the microbiota in breast milk from mothers of genetically predisposed offspring who presented CD showed a higher bacterial phylotype abundance and diversity, as well as a different bacterial composition, as compared with the mothers of unaffected offspring. These immune markers showed some associations with bacterial composition and may influence the risk for development of CD beyond early childhood.

Cross-Omics Analysis of Fenugreek Supplementation Reveals Beneficial Effects Are Caused by Gut Microbiome Changes Not Mammalian Host Physiology

Herbal remedies are increasing in popularity as treatments for metabolic conditions such as obesity and Type 2 Diabetes. One potential therapeutic option is fenugreek seeds (Trigonella foenum-graecum), which have been used for treating high cholesterol and Type 2 diabetes. A proposed mechanism for these benefits is through alterations in the microbiome, which impact mammalian host metabolic function. This study used untargeted metabolomics to investigate the fenugreek-induced alterations in the intestinal, liver, and serum profiles of mice fed either a 60% high-fat or low-fat control diet each with or without fenugreek supplementation (2% w/w) for 14 weeks. Metagenomic analyses of intestinal contents found significant alterations in the relative composition of the gut microbiome resulting from fenugreek supplementation. Specifically, Verrucomicrobia, a phylum containing beneficial bacteria which are correlated with health benefits, increased in relative abundance with fenugreek. Metabolomics partial least squares discriminant analysis revealed substantial fenugreek-induced changes in the large intestines. However, it was observed that while the magnitude of changes was less, significant modifications were present in the liver tissues resulting from fenugreek supplementation. Further analyses revealed metabolic processes affected by fenugreek and showed broad ranging impacts in multiple pathways, including carnitine biosynthesis, cholesterol and bile acid metabolism, and arginine biosynthesis. These pathways may play important roles in the beneficial effects of fenugreek.

Analysis of Faecal Microbiota and Small ncRNAs in Autism: Detection of miRNAs and piRNAs with Possible Implications in Host-Gut Microbiota Cross-Talk

Intestinal microorganisms impact health by maintaining gut homeostasis and shaping the host immunity, while gut dysbiosis associates with many conditions, including autism, a complex neurodevelopmental disorder with multifactorial aetiology. In autism, gut dysbiosis correlates with symptom severity and is characterised by a reduced bacterial variability and a diminished beneficial commensal relationship. Microbiota can influence the expression of host microRNAs that, in turn, regulate the growth of intestinal bacteria by means of bidirectional host-gut microbiota cross-talk. We investigated possible interactions among intestinal microbes and between them and host transcriptional modulators in autism. To this purpose, we analysed, by "omics" technologies, faecal microbiome, mycobiome, and small non-coding-RNAs (particularly miRNAs and piRNAs) of children with autism and neurotypical development. Patients displayed gut dysbiosis related to a reduction of healthy gut micro- and mycobiota as well as up-regulated transcriptional modulators. The targets of dysregulated non-coding-RNAs are involved in intestinal permeability, inflammation, and autism. Furthermore, microbial families, underrepresented in patients, participate in the production of human essential metabolites negatively influencing the health condition. Here, we propose a novel approach to analyse faeces as a whole, and for the first time, we detected miRNAs and piRNAs in faecal samples of patients with autism.