The interplay between the gut microbiota and the immune system

Microbiome miracles and their pioneering advances and future frontiers in cardiovascular disease

Cardiovascular diseases (CVDs) represent a significant global health challenge, underscoring the need for innovative approaches to prevention and treatment. Recent years have seen a surge in interest in unraveling the complex relationship between the gut microbiome and cardiovascular health. This article delves into current research on the composition, diversity, and impact of the gut microbiome on CVD development. Recent advancements have elucidated the profound influence of the gut microbiome on disease progression, particularly through key mediators like Trimethylamine-N-oxide (TMAO) and other microbial metabolites. Understanding these mechanisms reveals promising therapeutic targets, including interventions aimed at modulating the gut microbiome's interaction with the immune system and its contribution to endothelial dysfunction. Harnessing this understanding, personalized medicine strategies tailored to individuals' gut microbiome profiles offer innovative avenues for reducing cardiovascular risk. As research in this field continues to evolve, there is vast potential for transformative advancements in cardiovascular medicine, paving the way for precision prevention and treatment strategies to address this global health challenge.

Emerging trends and future challenges of advanced 2D nanomaterials for combating bacterial resistance

The number of multi-drug-resistant bacteria has increased over the last few decades, which has caused a detrimental impact on public health worldwide. In resolving antibiotic resistance development among different bacterial communities, new antimicrobial agents and nanoparticle-based strategies need to be designed foreseeing the slow discovery of new functioning antibiotics. Advanced research studies have revealed the significant disinfection potential of two-dimensional nanomaterials (2D NMs) to be severed as effective antibacterial agents due to their unique physicochemical properties. This review covers the current research progress of 2D NMs-based antibacterial strategies based on an inclusive explanation of 2D NMs' impact as antibacterial agents, including a detailed introduction to each possible well-known antibacterial mechanism. The impact of the physicochemical properties of 2D NMs on their antibacterial activities has been deliberated while explaining the toxic effects of 2D NMs and discussing their biomedical significance, dysbiosis, and cellular nanotoxicity. Adding to the challenges, we also discussed the major issues regarding the current quality and availability of nanotoxicity data. However, smart advancements are required to fabricate biocompatible 2D antibacterial NMs and exploit their potential to combat bacterial resistance clinically.

Unraveling the gut microbiota's role in Rheumatoid arthritis: dietary pathways to modulation and therapeutic potential

Rheumatoid arthritis (RA) is a significant global health issue. Recent research highlights the gut microbiota's critical role in RA's development, noting how dietary factors can alter these microbial communities. This has led to an increased focus on how the gut microbiota (GM) influences RA and the potential for dietary ingredients to offer anti-RA benefits by modifying GM. This review presents a concise examination of the GM associated with RA, identifying specific microbial taxa at various levels that are implicated in the disease. It delves into dietary components known for their anti-RA properties through GM modulation and their mechanisms. Findings from numerous studies, including both animal and human research, show significant differences in the GM composition between individuals with early and established RA. Certain microbes like Tenericutes, Synergistetes, and Proteobacteria have been linked to RA progression, whereas Bacteroidetes and some strains of Lactobacillus are shown to have protective effects against RA. Dietary elements such as fibers, polysaccharides, resistant starch, and peptides have been identified as influential in combating RA. These components work by altering the GM's metabolites and impacting immune cells related to the GM. This review suggests the potential for developing functional foods aimed at treating RA by targeting GM.

Efficient enzyme-free method to assess the development and maturation of the innate and adaptive immune systems in the mouse colon

Researchers who aim to globally analyze the gastrointestinal immune system via flow cytometry have many protocol options to choose from, with specifics generally tied to gut wall layers of interest. To get a clearer idea of the approach we should use on full-thickness colon samples from mice, we first undertook a systematic comparison of three tissue dissociation techniques: two based on enzymatic cocktails and the other one based on manual crushing. Using flow cytometry panels of general markers of lymphoid and myeloid cells, we found that the presence of cell-surface markers and relative cell population frequencies were more stable with the mechanical method. Both enzymatic approaches were associated with a marked decrease of several cell-surface markers. Using mechanical dissociation, we then developed two minimally overlapping panels, consisting of a total of 26 antibodies, for serial profiling of lymphoid and myeloid lineages from the mouse colon in greater detail. Here, we highlight how we accurately delineate these populations by manual gating, as well as the reproducibility of our panels on mouse spleen and whole blood. As a proof-of-principle of the usefulness of our general approach, we also report segment- and life stage-specific patterns of immune cell profiles in the colon. Overall, our data indicate that mechanical dissociation is more suitable and efficient than enzymatic methods for recovering immune cells from all colon layers at once. Additionally, our panels will provide researchers with a relatively simple tool for detailed immune cell profiling in the murine gastrointestinal tract, regardless of life stage or experimental conditions.

Gut microbiota modulation enhances the immune capacity of lizards under climate warming

BACKGROUND

Host-microbial interactions are expected to affect species' adaptability to climate change but have rarely been explored in ectothermic animals. Some studies have shown that short-term warming reduced gut microbial diversity that could hamper host functional performance.

RESULTS

However, our longitudinal experiments in semi-natural conditions demonstrated that warming decreased gut microbiota diversity at 2 months, but increased diversity at 13 and 27 months in a desert lizard (Eremias multiocellata). Simultaneously, long-term warming significantly increased the antibacterial activity of serum, immune responses (higher expression of intestinal immune-related genes), and the concentration of short-chain fatty acids (thereby intestinal barrier and immunity) in the lizard. Fecal microbiota transplant experiments further revealed that increased diversity of gut microbiota significantly enhanced antibacterial activity and the immune response of lizards. More specifically, the enhanced immunity is likely due to the higher relative abundance of Bacteroides in warming lizards, given that the bacteria of Bacteroides fragilis regulated IFN-β expression to increase the immune response of lizards under a warming climate.

CONCLUSIONS

Our study suggests that gut microbiota can help ectotherms cope with climate warming by enhancing host immune response, and highlights the importance of long-term studies on host-microbial interactions and their biological impacts.

The Association between Functional Dyspepsia and Metabolic Syndrome-The State of the Art

Functional dyspepsia is a common functional disorder of the gastrointestinal tract that is responsible for many primary care visits. No organic changes have been found to explain its symptoms. We hypothesize that modern lifestyles and environmental factors, especially psychological stress, play a crucial role in the high prevalence of functional dyspepsia and metabolic syndrome. While gastrointestinal tract diseases are rarely linked to metabolic disorders, chronic stress, obesity-related metabolic syndrome, chronic inflammation, intestinal dysbiosis, and functional dyspepsia have significant pathophysiological associations. Functional dyspepsia, often associated with anxiety and chronic psychological stress, can activate the neuroendocrine stress axis and immune system, leading to unhealthy habits that contribute to obesity. Additionally, intestinal dysbiosis, which is commonly present in functional dyspepsia, can exacerbate systemic inflammation and obesity, further promoting metabolic syndrome-related disorders. It is worth noting that the reverse is also true: obesity-related metabolic syndrome can worsen functional dyspepsia and its associated symptoms by triggering systemic inflammation and intestinal dysbiosis, as well as negative emotions (depression) through the brain-gut axis. To understand the pathophysiology and deliver an effective treatment strategy for these two difficult-to-cure disorders, which are challenging for both caregivers and patients, a psychosocial paradigm is essential.

Gut microbiota-derived LCA mediates the protective effect of PEDV infection in piglets

BACKGROUND

The gut microbiota is a critical factor in the regulation of host health, but the relationship between the differential resistance of hosts to pathogens and the interaction of gut microbes is not yet clear. Herein, we investigated the potential correlation between the gut microbiota of piglets and their disease resistance using single-cell transcriptomics, 16S amplicon sequencing, metagenomics, and untargeted metabolomics.

RESULTS

Porcine epidemic diarrhea virus (PEDV) infection leads to significant changes in the gut microbiota of piglets. Notably, Landrace pigs lose their resistance quickly after being infected with PEDV, but transplanting the fecal microbiota of Min pigs to Landrace pigs alleviated the infection status. Macrogenomic and animal protection models identified Lactobacillus reuteri and Lactobacillus amylovorus in the gut microbiota as playing an anti-infective role. Moreover, metabolomic screening of the secondary bile acids' deoxycholic acid (DCA) and lithocholic acid (LCA) correlated significantly with Lactobacillus reuteri and Lactobacillus amylovorus, but only LCA exerted a protective function in the animal model. In addition, LCA supplementation altered the distribution of intestinal T-cell populations and resulted in significantly enriched CD8+ CTLs, and in vivo and in vitro experiments showed that LCA increased SLA-I expression in porcine intestinal epithelial cells via FXR receptors, thereby recruiting CD8+ CTLs to exert antiviral effects.

CONCLUSIONS

Overall, our findings indicate that the diversity of gut microbiota influences the development of the disease, and manipulating Lactobacillus reuteri and Lactobacillus amylovorus, as well as LCA, represents a promising strategy to improve PEDV infection in piglets. Video Abstract.

Adolescent alcohol drinking interaction with the gut microbiome: implications for adult alcohol use disorder

Reciprocal communication between the gut microbiota and the brain, commonly referred to as the "gut-brain-axis" is crucial in maintaining overall physiological homeostasis. Gut microbiota development and brain maturation (neuronal connectivity and plasticity) appear to be synchronized and to follow the same timeline during childhood (immature), adolescence (expansion) and adulthood (completion). It is important to note that the mesolimbic reward circuitry develops early on, whereas the maturation of the inhibitory frontal cortical neurons is delayed. This imbalance can lead to increased acquirement of reward-seeking and risk-taking behaviors during adolescence, and consequently eventuate in heightened risk for substance abuse. Thus, there is high initiation of alcohol drinking in early adolescence that significantly increases the risk of alcohol use disorder (AUD) in adulthood. The underlying causes for heightened AUD risk are not well understood. It is suggested that alcohol-associated gut microbiota impairment during adolescence plays a key role in AUD neurodevelopment in adulthood. Furthermore, alcohol-induced dysregulation of microglia, either directly or indirectly through interaction with gut microbiota, may be a critical neuroinflammatory pathway leading to neurodevelopmental impairments and AUD. In this review article, we highlight the influence of adolescent alcohol drinking on gut microbiota, gut-brain axis and microglia, and eventual manifestation of AUD. Furthermore, novel therapeutic interventions via gut microbiota manipulations are discussed briefly.

Engineering Strategies to Modulate the Gut Microbiome and Immune System

The gut microbiota, predominantly residing in the colon, is a complex ecosystem with a pivotal role in the host immune system. Dysbiosis of the gut microbiota has been associated with various diseases, and there is an urgent need to develop new therapeutics that target the microbiome and restore immune functions. This Brief Review discusses emerging therapeutic strategies that focus on oral delivery systems for modulating the gut microbiome. These strategies include genetic engineering of probiotics, probiotic-biomaterial hybrids, dietary fibers, and oral delivery systems for microbial metabolites, antimicrobial peptides, RNA, and antibiotics. Engineered oral formulations have demonstrated promising outcomes in reshaping the gut microbiome and influencing immune responses in preclinical studies. By leveraging these approaches, the interplay between the gut microbiota and the immune system can be harnessed for the development of novel therapeutics against cancer, autoimmune disorders, and allergies.

Selective breeding of rats for high (HAB) and low (LAB) anxiety-related behaviour: A unique model for comorbid depression and social dysfunctions

Animal models of selective breeding for extremes in emotionality are a strong experimental approach to model psychopathologies. They became indispensable in order to increase our understanding of neurobiological, genetic, epigenetic, hormonal, and environmental mechanisms contributing to anxiety disorders and their association with depressive symptoms or social deficits. In the present review, we extensively discuss Wistar rats selectively bred for high (HAB) and low (LAB) anxiety-related behaviour on the elevated plus-maze. After 30 years of breeding, we can confirm the prominent differences between HAB and LAB rats in trait anxiety, which are accompanied by consistent differences in depressive-like, social and cognitive behaviours. We can further confirm a single nucleotide polymorphism in the vasopressin promotor of HAB rats causative for neuropeptide overexpression, and show that low (or high) anxiety and fear levels are unlikely due to visual dysfunctions. Thus, HAB and LAB rats continue to exist as a reliable tool to study the multiple facets underlying the pathology of high trait anxiety and its comorbidity with depression-like behaviour and social dysfunctions.

Prevention and Health Benefits of Prebiotics, Probiotics and Postbiotics in Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common type of leukemia in children, comprising 75-85% of cases. Aggressive treatment of leukemias includes chemotherapy and antibiotics that often disrupt the host microbiota. Additionally, the gut microbiota may play a role in the development and progression of acute leukemia. Prebiotics, probiotics, and postbiotics are considered beneficial to health. The role of prebiotics in the treatment and development of leukemia is not well understood, but inulin can be potentially used in the treatment of leukemia. Some probiotic bacteria such as Lactobacillus shows anticancer activity in in vitro studies. Additionally, Bifidobacterium spp., as a consequence of the inhibition of growth factor signaling and mitochondrial-mediated apoptosis, decrease the proliferation of cancer cells. Many bacterial metabolites have promising anticancer potential. The available research results are promising. However, more research is needed in humans, especially in the child population, to fully understand the relationship between the gut microbiota and acute leukemia.

Cross-Kingdom Interaction of miRNAs and Gut Microbiota with Non-Invasive Diagnostic and Therapeutic Implications in Colorectal Cancer

Colorectal cancer (CRC) has one of the highest incidences among all types of malignant diseases, affecting millions of people worldwide. It shows slow progression, making it preventable. However, this is not the case due to shortcomings in its diagnostic and management procedure and a lack of effective non-invasive biomarkers for screening. Here, we discuss CRC-associated microRNAs (miRNAs) and gut microbial species with potential as CRC diagnostic and therapy biomarkers. We provide rich evidence of cross-kingdom miRNA-mediated interactions between the host and gut microbiome. miRNAs have emerged with the ability to shape the composition and dynamics of gut microbiota. Intestinal microbes can uptake miRNAs, which in turn influence microbial growth and provide the ability to regulate the abundance of various microbial species. In the context of CRC, targeting miRNAs could aid in manipulating the balance of the microbiota. Our findings suggest the need for correlation analysis between the composition of the gut microbiome and the miRNA expression profile.

The Effects of Social Experience on Host Gut Microbiome in Male Zebrafish (Danio rerio)

AbstractAlthough the gut and the brain vastly differ in physiological function, they have been interlinked in a variety of different neurological and behavioral disorders. The bacteria that comprise the gut microbiome communicate and influence the function of various physiological processes within the body, including nervous system function. However, the effects of social experience in the context of dominance and social stress on gut microbiome remain poorly understood. Here, we examined whether social experience impacts the host zebrafish (Danio rerio) gut microbiome. We studied how social dominance during the first 2 weeks of social interactions changed the composition of zebrafish gut microbiome by comparing gut bacterial composition, diversity, and relative abundance between socially dominant, submissive, social isolates and control group-housed communal fish. Using amplicon sequencing of the 16S rRNA gene, we report that social dominance significantly affects host gut bacterial community composition but not bacterial diversity. At the genus level, Aeromonas and unclassified Enterobacteriaceae relative abundance decreased in dominant individuals while commensal bacteria (e.g., Exiguobacterium and Cetobacterium) increased in relative abundance. Conversely, the relative abundance of Psychrobacter and Acinetobacter was increased in subordinates, isolates, and communal fish compared to dominant fish. The shift in commensal and pathogenic bacteria highlights the impact of social experience and the accompanying stress on gut microbiome, with potentially similar effects in other social organisms.

Bacterial gut microbiome differences in adults with ADHD and in children with ADHD on psychostimulant medication

Recent evidence suggests that there is a link between neurodevelopmental disorders, such as attention deficit hyperactivity disorder (ADHD), and the gut microbiome. However, most studies to date have had low sample sizes, have not investigated the impact of psychostimulant medication, and have not adjusted for potential confounders, including body mass index, stool consistency and diet. To this end, we conducted the largest, to our knowledge, fecal shotgun metagenomic sequencing study in ADHD, with 147 well-characterized adult and child patients. For a subset of individuals, plasma levels of inflammatory markers and short-chain fatty acids were also measured. In adult ADHD patients (n=84), compared to controls (n=52), we found a significant difference in beta diversity both regarding bacterial strains (taxonomic) and bacterial genes (functional). In children with ADHD (n=63), we found that those on psychostimulant medication (n=33 on medication vs. n=30 not on medication) had (i) significantly different taxonomic beta diversity, (ii) lower functional and taxonomic evenness, (iii) lower abundance of the strain Bacteroides stercoris CL09T03C01 and bacterial genes encoding an enzyme in vitamin B₁₂ synthesis, and (iv) higher plasma levels of vascular inflammatory markers sICAM-1 and sVCAM-1. Our study continues to support a role for the gut microbiome in neurodevelopmental disorders and provides additional insights into the effects of psychostimulant medication. However, additional studies are needed to replicate these findings and examine causal relationships with the disorder.

Extracellular Vesicles of Probiotics: Shedding Light on the Biological Activity and Future Applications

For many decades, the proper functioning of the human body has become a leading scientific topic. In the course of numerous experiments, a striking impact of probiotics on the human body has been documented, including maintaining the physiological balance of endogenous microorganisms, regulating the functioning of the immune system, enhancing the digestive properties of the host, and preventing or alleviating the course of many diseases. Recent research, especially from the last decade, shows that this health-benefiting activity of probiotics is largely conditioned by the production of extracellular vesicles. Although the importance of extracellular vesicles in the virulence of many live-threatening pathogens is widely described in the literature, much less is known with respect to the health-promoting effect of extracellular vesicles secreted by non-pathogenic microorganisms, including probiotics. Based on this, in the current review article, we decided to collect the latest literature data on the health-inducing properties of extracellular vesicles secreted by probiotics. The characteristics of probiotics' extracellular vesicles will be extended by the description of their physicochemical properties and the proteome in connection with the biological activities exhibited by these structures.

Sex Differences of Radiation Damage in High-Fat-Diet-Fed Mice and the Regulatory Effect of Melatonin

The consumption of a high-fat diet (HFD) and exposure to ionizing radiation (IR) are closely associated with many diseases. To evaluate the interaction between HFDs and IR-induced injury, we gave mice whole abdominal irradiation (WAI) to examine the extent of intestinal injury under different dietary conditions. Melatonin (MLT) is a free radical scavenger that effectively prevents hematopoietic, immune, and gastrointestinal damage induced by IR. However, its effects on WAI-induced intestinal injury in HFD-fed mice remain unclear. We demonstrated that MLT can promote intestinal structural repair following WAI and enhance the regeneration capacity of Lgr5⁺ intestinal stem cells. In addition, we investigated the effects of radiation damage on sexual dimorphism in HFD-fed mice. The results showed that the degree of IR-induced intestinal injury was more severe in the HFD-fed female mice. MLT preserved the intestinal microbiota composition of HFD-fed mice and increased the abundance of Bacteroides and Proteobacteria in male and female mice, respectively. In conclusion, MLT may reduce the negative effects of HFD and IR, thereby providing assistance in preserving the structure and function of the intestine.

Apoptotic biliary epithelial cells and gut dysbiosis in the induction of murine primary biliary cholangitis

Primary biliary cholangitis (PBC) is a female-predominant liver autoimmune disease characterized by the specific immune-mediated destruction of the intrahepatic small bile duct. Although apoptosis of biliary epithelial cells (BECs) and alterations in gut microbiota are observed in patients with PBC, it is still unclear whether these events happen in the early stage and cause the breakdown of tolerance in PBC. In this study, we examined the early events in the loss of tolerance in our well-defined 2-OA-OVA-induced murine autoimmune cholangitis (AIC) model. We report herein that apoptosis of BECs was notable in the early stage of murine AIC. An altered gut microbiota, in particular, an increased percentage of gram-positive Firmicutes in AIC mice was also observed. BECs in AIC mice expressed adhesion molecule ICAM-1, cytokines/chemokines TNF-α, CCL2, CXCL9, CXCL10, and toll-like receptor (TLR) 2. Moreover, BECs treated with TLR2 ligand had elevated apoptosis and CXCL10 production. These data collectively suggest a new mechanism of tolerance breakdown in AIC. Altered gut microbiota induces apoptosis of BECs through TLR2 signaling. BECs secrete chemokines to recruit CD8 T cells to damage BECs further.

Intestinal Microflora Characteristics of Antheraea pernyi (Lepidoptera: Saturniidae) Larvae With Vomit Disease

Antheraea pernyi Guérin-Méneville (Lepidoptera: Saturniidae) is of high economic value as a source of silk, food, and bioactive substances with medicinal properties. A. pernyi larvae are prone to A. pernyi vomit disease (AVD), which results in substantial economic losses during cultivation; however, the relationship between AVD and A. pernyi gut microbiota remains unclear. Here, we investigated the bacterial community in the midgut and feces of A. pernyi larvae with and without AVD using 16S rRNA gene sequencing with Illumina MiSeq technology. Compared with healthy larvae, intestinal bacterial diversity and community richness increased and decreased in larvae with mild and severe AVD, respectively. In addition, the proportion of gut Enterobacter Hormaeche and Edwards(Enterobacteriales: Enterobacteriaceae) and Enterococcus Thiercelin and Jouhaud (Lactobacillales: Enterococcaceae) was higher and lower, respectively, in larvae with mild AVD than those in healthy larvae. A. pernyi vomit disease infection significantly increased the genera with abundance <1%. In the gut of larvae with severe AVD, the proportion of Turicibacter Bosshard et al. (Erysipelotrichales: Turicibacteraceae) increased significantly to 81.53-99.92%, whereas that of Enterobacter decreased compared with healthy larvae. However, the diversity of fecal bacteria was similar between healthy larvae and those with mild AVD. Overall, the findings demonstrate that intestinal microflora in A. pernyi larvae are altered by AVD infection and may cause secondary bacterial infection. This is the first report of the presence of Turicibacter in the intestinal tract of lepidopterans.

Th17-Derived Cytokines Synergistically Enhance IL-17C Production by the Colonic Epithelium

Tightly regulated communication between the gastrointestinal epithelium and immune cells in the underlying lamina propria is critical for immune homeostasis and inflammation. IL-17C, produced by epithelial cells after exposure to inflammatory stimuli, facilitates cell-to-cell communication by promoting inflammatory responses in Th17 cells. In this study, we demonstrate that Th17-derived cytokines TNF-α, IL-17A, and IL-22 synergistically enhance IL-17C expression in both human-transformed colonic epithelial cell lines and primary non-inflammatory bowel disease colonic epithelial spheroids. This synergistic expression requires activation of the transcription factor NF-κB downstream of the TNF-α stimulus, evidenced by the reduction of IL-17C expression in the presence of an IκBα inhibitor. IL-17A and IL-22 enhance IL-17C expression through the activation of the transcription factor AP-1 in a p38 MAPK-dependent manner. Colonic spheroids derived from uninvolved epithelial of ulcerative colitis patients stimulated with TNF-α, IL-17A, and IL-22 show muted responses compared with non-inflammatory bowel disease spheroids, and inflamed spheroids yielded more IL-17C expression in the presence of TNF-α, and no response to IL-22 stimulation. Altogether, a role for IL-17C in activating Th17 cells combined with our findings of Th17-derived cytokine-driven synergy in the expression of IL-17C identifies a novel inflammatory amplification loop in the gastrointestinal tract between epithelial cells and Th17 cells.

Understanding the cross-talk between human microbiota and gastrointestinal cancer for developing potential diagnostic and prognostic biomarkers

The interaction between gut microbes and gastrointestinal (GI) tract carcinogenesis has always attracted researchers' attention to identify therapeutic targets or potential prognostic biomarkers. Various studies have suggested that the microbiota do show inflammation and immune dysregulation, which led to carcinogenesis in GI tract. In this review, we have focused on the role of microbes present in the gut, intestine, or faeces in GI tract cancers, including esophageal cancer, gastric cancer, and colorectal cancer. Herein, we have discussed the importance of the microbes and their metabolites, which could serve as diagnostic biomarkers for cancer detection, especially in the early stage, and prognostic markers. To maximize the effect of the treatment strategies, an accurate evaluation of the prognosis is imperative for clinicians. There is a vast difference in the microbiota profiles within a population and across the populations depending upon age, diet, lifestyle, genetic makeup, use of antibiotics, and environmental factors. Therefore, the diagnostic efficiency of the microbial markers needs to be further validated. A deeper understanding of the GI cancer and the host microbiota is needed to acquire pivotal information about disease status.

[Latent and Active Tuberculosis Infection in Patients with Inflammatory Bowel Disease]

Latent tuberculosis (TB) infections (LTBI) impose clinical challenges in terms of the diagnosis and treatment of inflammatory bowel disease (IBD), especially in TB-endemic areas. While steroids and biologics have become increasingly useful in the treatment of patients with moderate-to-severe IBD, the risk of reactivation or developing TB is increased due to their potent immunosuppressive effects. Tumor necrosis factor-alpha inhibition may result in the activation of a latent TB infection, and most cases manifest as more severe forms of disseminated TB. All potential users of immunosuppressive therapy should be screened for LTBI, and appropriate measures for the management of latent and active TB should be undertaken with immediate initiation of anti-TB treatment. Biologics should be withheld during TB treatment, and the proper timing for the resumption of IBD therapy during or after TB treatment should be individualized. This review summarizes the latest knowledge on the risk assessment, detection, and management of latent and active TB infections in patients with IBD.

Heat-inactivated Lacticaseibacillus paracasei N1115 alleviates the damage due to brain function caused by long-term antibiotic cocktail exposure in mice

Critical development period of intestinal microbiota occurs concurrently with brain development, and their interaction is influenced by the microbiota–gut–brain axis. This study examined how antibiotics exposure affected gut microbiota and brain development and analyzed the possible benefits of heat-inactivated Lacticaseibacillus paracasei N1115 (N1115). Thirty neonatal male mice were randomly divided into three groups and treated with sterilized water (control), an antibiotic cocktail (Abx), or antibiotics plus heat-inactivated N1115 (Abx + N1115) for 84 days. We found that while the mRNA levels of GABA_Aα1, GABA_b1, and glucocorticoid receptor (GR) in the hippocampus and brain-derived neurotrophic factor (BDNF), GABA_Aα1, GABA_b1, and nerve growth factor (NGF) in the prefrontal cortex were higher, the mRNA levels of 5-HT_1A were lower in the Abx group. The Abx + N1115 group had lower mRNA levels of GABA_Aα1, GABA_b1, and GR in the hippocampus and BDNF, GABA_b1, and NGF in the prefrontal cortex than the Abx group. The latency period was longer in the Morris water maze test while longer rest time was seen in tail suspension test in the Abx group than the control and Abx + N1115 groups. In the open field test, the moving time and distance of the Abx group were reduced. Further, the alpha-diversity indexes of the Abx and Abx + N1115 groups were significantly lower than the control. Further, long-term exposure to antibiotics disrupted the intestinal microbiota as evidenced by decreased Bacteroides, Firmicutes, and Lactobacillus, and increased Proteobacteria and Citrobacter. However, N1115 significantly decreased the abundance of Citrobacter when compared with those in the Abx group. These results indicate that antibiotics can substantially damage the intestinal microbiota and cognitive function, causing anxiety and depression, which can be alleviated by heat-inactivated N1115 via modulation of the microbiota–gut–brain axis.

Effects of Fucoidan Isolated From Laminaria japonica on Immune Response and Gut Microbiota in Cyclophosphamide-Treated Mice

The effects of Laminaria japonica fucoidan (LF) on immune regulation and intestinal microflora in cyclophosphamide (CTX)-treated mice were investigated in this work. Results indicated that LF significantly enhanced the spleen and thymus indices, promoted spleen lymphocyte and peritoneal macrophages proliferation, and increased the immune-related cytokines production in serum. Moreover, LF could regulate intestinal flora composition, increasing the abundance of Lactobacillaceae and Alistipes, and inhibiting Erysipelotrichia, Turicibacter, Romboutsia, Peptostreptococcaceae, and Faecalibaculum. These results were positively correlated with immune characteristics. Overall, LF could be useful as a new potential strategy to mitigate CTX immunosuppression and intestinal microbiota disorders.

Mechanisms of Action of Ozone Therapy in Emerging Viral Diseases: Immunomodulatory Effects and Therapeutic Advantages With Reference to SARS-CoV-2

Medical oxygen-ozone (O₂-O₃) is a successful therapeutic approach accounting on the assessed beneficial action of ozone in the range 30–45 μg/ml (expanded range 10–80 μg/ml according to different protocols), as in this dosage range ozone is able to trigger a cellular hormetic response via the modulating activity of reactive oxygen species (ROS), as signaling molecules. The ozone-dependent ROS-mediated fatty acid oxidation leads to the formation of lipid ozonization products (LOPs), which act as signal transducers by triggering ROS signaling and therefore mitohormetic processes. These processes ultimately activate survival mechanisms at a cellular level, such as the Nrf2/Keap1/ARE system activation, the AMPK/FOXO/mTOR/Sir1 pathway and the Nrf2/NF-kB cross talk. Furthermore, indirectly, via these pathways, LOPs trigger the HIF-1α pathway, the HO-1 signaling and the NO/iNOS biochemical machinery. Ozone-driven shift of cytokine activation pathways, from pro-inflammatory to anti-inflammatory immediately afterwards, also exert direct immunoregulatory effects on regulatory T lymphocytes as well as on the intestinal microbiota, which in turn can affect immune response thus influencing the progression of the disease. In this review, we will describe the biological and biochemical mechanisms of action of ozone therapy with the aim of evaluating both positive and critical aspects of ozone use as a therapeutic adjuvant in the light of emerging viral infections, such as SARS-CoV-2 and microbiome-associated disorders related to SARS-CoV-2.

Best Practices for Probiotic Research in Athletic and Physically Active Populations: Guidance for Future Randomized Controlled Trials

Probiotic supplementation, traditionally used for the prevention or treatment of a variety of disease indications, is now recognized in a variety of population groups including athletes and those physically active for improving general health and performance. However, experimental and clinical trials with probiotics commonly suffer from design flaws and different outcome measures, making comparison and synthesis of conclusions difficult. Here we review current randomized controlled trials (RCTs) using probiotics for performance improvement, prevention of common illnesses, or general health, in a specific target population (athletes and those physically active). Future RCTs should address the key elements of (1) properly defining and characterizing a probiotic intervention, (2) study design factors, (3) study population characteristics, and (4) outcome measures, that will allow valid conclusions to be drawn. Careful evaluation and implementation of these elements should yield improved trials, which will better facilitate the generation of evidence-based probiotic supplementation recommendations for athletes and physically active individuals.

A systematic review on the effects of nanomaterials on gut microbiota

•

Nanomaterials have been shown to affect gut microbiota (GM) both in vivo and in vitro.

•

The effects have been shown to depend on size, dose, dose duration and functional groups.

•

In general, more studies seem to indicate dose-dependent adverse effects of NMs towards GM.

•

Standardized protocols are needed for characterization of NMs, dosing, and test systems (both in vitro and in vivo).

Some nanomaterials (NMs) have been shown to possess antimicrobial activity and cause GM dysbiosis. Since NMs are being used widely, a systematic assessment of the effects of NMs on GM is warranted. In this systematic review, a total of 46 in vivo and 22 in vitro studies were retrieved from databases and search engines including Science-Direct, Pubmed and Google scholar. Criteria for assessment of studies included use of in vitro or in vivo studies, characterization of NMs, use of single or multiple doses as well as consistency of results. GM dysbiosis has been studied most widely on TiO₂, Ag, Zn-based NMs. There was moderate evidence for GM dysbiosis caused by Zn- and Cu-based NMs, Cu-loaded chitosan NPs and Ag NMs, and anatase TiO₂ NPs, as well as low evidence for SWCNTs, nanocellulose, SiO₂, Se, nanoplastics, CeO_2, MoO₃ and graphene-based NMs. Most studies indicate adverse effects of NMs towards GM. However, more work is required to elucidate the differences on the reported effects of NM by type and sex of organisms, size, shape and surface properties of NMs as well as effects of exposure to mixtures of NMs. For consistency and better agreement among studies on GM dysbiosis, there is need for internationally agreed protocols on, inter alia, characterization of NMs, dosing (amounts, frequency and duration), use of sonication, test systems (both in vitro and in vivo), including oxygen levels for in vitro models.

Red Cusk-Eel (Genypterus chilensis) Gut Microbiota Description of Wild and Aquaculture Specimens

Chile has promoted the diversification of aquaculture and red cusk-eel (Genypterus chilensis) is one of the prioritized species. However, many aspects of the biology of the species are unknown or have little information available. These include intestinal microbiota, an element that may play an important role in the nutrition and defense of cultured animals for meat production. This study compares the microbiota composition of the intestinal contents of wild and aquaculture fish to explore the microbial communities present and their potential contribution to the host. DNA was extracted from the intestinal content samples and the V4 region of the 16S rRNA gene was amplified and sequenced using the Ion Torrent platform. After the examination of the sequences, strong differences were found in the composition at the level of phylum, being Firmicutes and Tenericutes the most abundant in aquaculture and wild condition, respectively. At the genus level, the Vagococcus (54%) and Mycoplasma (97%) were the most prevalent in the microbial community of aquaculture and wild condition, respectively. The evaluation of predicted metabolic pathways in these metagenomes showed that in wild condition there is an important presence of lipid metabolism belonging to the unsaturated fatty acid synthesis. In the aquaculture condition, the metabolism of terpenoids and polyketides were relevant. To our knowledge, this is the first study to characterize and compare the intestinal microbiota of red cusk-eel (Genypterus chilensis) of wild and aquaculture origin using high-throughput sequencing.

Butyl-fructooligosaccharides modulate gut microbiota in healthy mice and ameliorate ulcerative colitis in a DSS-induced model

Butyl-fructooligosaccharides (B-FOSs) are newly synthesized prebiotics composed of short-chain FOS (GF2, 1-kestose; GF3, nystose; GF4, fructofuranosyl-nystose; GF5, 1-F-(1-b-D-fructofuranosyl)-2-nystose) bound with one or two butyric groups by ester bonds. Previous in...

Microbes, metabolites and (synaptic) malleability, oh my! The effect of the microbiome on synaptic plasticity

The microbiome influences the emotional and cognitive phenotype of its host, as well as the neurodevelopment and pathophysiology of various brain processes and disorders, via the well‐established microbiome–gut–brain axis. Rapidly accumulating data link the microbiome to severe neuropsychiatric disorders in humans, including schizophrenia, Alzheimer's and Parkinson's. Moreover, preclinical work has shown that perturbation of the microbiome is closely associated with social, cognitive and behavioural deficits. The potential of the microbiome as a diagnostic and therapeutic tool is currently undercut by a lack of clear mechanistic understanding of the microbiome–gut–brain axis. This review establishes the hypothesis that the mechanism by which this influence is carried out is synaptic plasticity – long‐term changes to the physical and functional neuronal structures that enable the brain to undertake learning, memory formation, emotional regulation and more. By examining the different constituents of the microbiome–gut–brain axis through the lens of synaptic plasticity, this review explores the diverse aspects by which the microbiome shapes the behaviour and mental wellbeing of the host. Key elements of this complex bi‐directional relationship include neurotransmitters, neuronal electrophysiology, immune mediators that engage with both the central and enteric nervous systems and signalling cascades that trigger long‐term potentiation of synapses. The importance of establishing mechanistic correlations along the microbiome–gut–brain axis cannot be overstated as they hold the potential for furthering current understanding regarding the vast fields of neuroscience and neuropsychiatry. This review strives to elucidate the promising theory of microbiome‐driven synaptic plasticity in the hope of enlightening current researchers and inspiring future ones.

BMI, Alcohol Consumption and Gut Microbiome Species Richness Are Related to Structural and Functional Neurological Abnormalities

Background: The incidence of neurological diseases is increasing throughout the world. The aim of the present study was to identify nutrition and microbiome factors related to structural and functional neurological abnormalities to optimize future preventive strategies. Methods: Two hundred thirty-eight patients suffering from (1) structural (neurodegeneration) or (2) functional (epilepsy) neurological abnormalities or (3) chronic pain (migraine) and 612 healthy control subjects were analyzed by validated 12-month food frequency questionnaire (FFQ) and 16S rRNA microbiome sequencing (from stool samples). A binomial logistic regression model was applied for risk calculation and functional pathway analysis to show which functional pathway could discriminate cases and healthy controls. Results: Detailed analysis of more than 60 macro- and micronutrients revealed no distinct significant difference between cases and controls, whereas BMI, insulin resistance and metabolic inflammation in addition to alcohol consumption were major drivers of an overall neurological disease risk. The gut microbiome analysis showed decreased alpha diversity (Shannon index: p = 9.1× 10⁻⁷) and species richness (p = 1.2 × 10⁻⁸) in the case group as well as significant differences in beta diversity between cases and controls (Bray–Curtis: p = 9.99 × 10⁻⁴; Jaccard: p = 9.99 × 10⁻⁴). The Shannon index showed a beneficial effect (OR = 0.59 (95%-CI (0.40, 0.87); p = 8 × 10⁻³). Cases were clearly discriminated from healthy controls by environmental information processing, signal transduction, two component system and membrane transport as significantly different functional pathways. Conclusions: In conclusion, our data indicate that an overall healthy lifestyle, in contrast to supplementation of single micro- or macronutrients, is most likely to reduce overall neurological abnormality risk and that the gut microbiome is an interesting target to develop novel preventive strategies.

Results of the Seventh Scientific Workshop of ECCO: Precision Medicine in IBD-What, Why, and How

Many diseases that affect modern humans fall in the category of complex diseases, thus called because they result from a combination of multiple aetiological and pathogenic factors. Regardless of the organ or system affected, complex diseases present major challenges in diagnosis, classification, and management. Current forms of therapy are usually applied in an indiscriminate fashion based on clinical information, but even the most advanced drugs only benefit a limited number of patients and to a variable and unpredictable degree. This 'one measure does not fit all' situation has spurred the notion that therapy for complex disease should be tailored to individual patients or groups of patients, giving rise to the notion of 'precision medicine' [PM]. Inflammatory bowel disease [IBD] is a prototypical complex disease where the need for PM has become increasingly clear. This prompted the European Crohn's and Colitis Organisation to focus the Seventh Scientific Workshop on this emerging theme. The articles in this special issue of the Journal address the various complementary aspects of PM in IBD, including what PM is; why it is needed and how it can be used; how PM can contribute to prediction and prevention of IBD; how IBD PM can aid in prognosis and improve response to therapy; and the challenges and future directions of PM in IBD. This first article of this series is structured on three simple concepts [what, why, and how] and addresses the definition of PM, discusses the rationale for the need of PM in IBD, and outlines the methodology required to implement PM in IBD in a correct and clinically meaningful way.

An engineered probiotic secreting Sj16 ameliorates colitis via Ruminococcaceae/butyrate/retinoic acid axis

Most inflammatory bowel disease (IBD) patients are unable to maintain a lifelong remission. Developing a novel therapeutic strategy is urgently needed. In this study, we adopt a new strategy to attenuate colitis using the Escherichia coli Nissle 1917 probiotic strain to express a schistosome immunoregulatory protein (Sj16) in the gastrointestinal tract. The genetically engineered Nissle 1917 (EcN-Sj16) highly expressed Sj16 in the gastrointestinal tracts of dextran sulfate sodium-induced colitis mice and significantly attenuated the clinical activity of colitis mice. Mechanistically, EcN-Sj16 increased the intestinal microbiota diversity and selectively promoted the growth of Ruminococcaceae and therefore enhanced the butyrate production. Butyrate induced the expression of retinoic acid, which further attenuated the clinical activity of colitis mice by increasing Treg cells and decreasing Th17. Strikingly, retinoic acid inhibitor inhibited the therapeutic effects of EcN-Sj16 in colitis mice. These findings suggest that EcN-Sj16 represents a novel engineered probiotic that may be used to treat IBD.

Ameliorative Effects of Peptides Derived from Oyster (Crassostrea gigas) on Immunomodulatory Function and Gut Microbiota Structure in Cyclophosphamide-Treated Mice

The intestinal flora is recognized as a significant contributor to the immune system. In this research, the protective effects of oyster peptides on immune regulation and intestinal microbiota were investigated in mice treated with cyclophosphamide. The results showed that oyster peptides restored the indexes of thymus, spleen and liver, stimulated cytokines secretion and promoted the relative mRNA levels of Th1/Th2 cytokines (IL-2, IFN-γ, IL-4 and IL-10). The mRNA levels of Occludin, Claudin-1, ZO-1, and Mucin-2 were up-regulated, and the NF-κB signaling pathway was also activated after oyster peptides administration. Furthermore, oyster peptides treatment reduced the proportion of Firmicutes/Bacteroidetes, increased the relative abundance of Alistipes, Lactobacillus, Rikenell and the content of short-chain fatty acids, and reversed the composition of intestinal microflora similar to that of normal mice. In conclusion, oyster peptides effectively ameliorated cyclophosphamide-induced intestinal damage and modified gut microbiota structure in mice, and might be utilized as a beneficial ingredient in functional foods for immune regulation.

Etiopathogenesis and Diagnostic Strategies in Autoimmune Hepatitis

Autoimmune hepatitis (AIH) is a chronic liver disease with the incidence of 10 to 17 per 100,000 people in Europe. It affects people of any age, but most often occurs in the 40-60 age group. The clinical picture is varied, from asymptomatic to severe acute hepatitis or liver failure. The disease onset is probably associated with the impaired function of T lymphocytes, the development of molecular mimicry, intestinal dysbiosis, or infiltration with low density neutrophils, which, alongside autoantibodies (i.e., ANA, ASMA), implicate the formation of neutrophil extracellular traps (NETs), as a component of the disease process, and mediate the inappropriate immune response. AIH is characterized with an increased activity of aminotransferases, elevated concentration of serum immunoglobulin G, the presence of circulating autoantibodies and liver inflammation. The result of the histological examination of the liver and the presence of autoantibodies, although not pathognomonic, still remain a distinguishing feature. The diagnosis of AIH determines lifelong treatment in most patients. The treatment is implemented to prevent the development of cirrhosis and end-stage liver failure. This work focuses mainly on the etiopathogenesis and diagnosis of AIH.

Mechanisms of Immunotoxicity: Stressors and Evaluators

The immune system defends the body against certain tumor cells and against foreign agents such as fungi, parasites, bacteria, and viruses. One of its main roles is to distinguish endogenous components from non-self-components. An unproperly functioning immune system is prone to primary immune deficiencies caused by either primary immune deficiencies such as genetic defects or secondary immune deficiencies such as physical, chemical, and in some instances, psychological stressors. In the manuscript, we will provide a brief overview of the immune system and immunotoxicology. We will also describe the biochemical mechanisms of immunotoxicants and how to evaluate immunotoxicity.

Stem Cells and Innate Immunity in Aquatic Invertebrates: Bridging Two Seemingly Disparate Disciplines for New Discoveries in Biology

The scopes related to the interplay between stem cells and the immune system are broad and range from the basic understanding of organism's physiology and ecology to translational studies, further contributing to (eco)toxicology, biotechnology, and medicine as well as regulatory and ethical aspects. Stem cells originate immune cells through hematopoiesis, and the interplay between the two cell types is required in processes like regeneration. In addition, stem and immune cell anomalies directly affect the organism's functions, its ability to cope with environmental changes and, indirectly, its role in ecosystem services. However, stem cells and immune cells continue to be considered parts of two branches of biological research with few interconnections between them. This review aims to bridge these two seemingly disparate disciplines towards much more integrative and transformative approaches with examples deriving mainly from aquatic invertebrates. We discuss the current understanding of cross-disciplinary collaborative and emerging issues, raising novel hypotheses and comments. We also discuss the problems and perspectives of the two disciplines and how to integrate their conceptual frameworks to address basic equations in biology in a new, innovative way.

Gut microbiota-mediated pesticide toxicity in humans: Methodological issues and challenges in the risk assessment of pesticides

Many in vivo and in vitro studies have shown that pesticides can disrupt the functioning of gut microbiota (GM), which can lead to many diseases in humans. While the tests developed by the Organization of Economic Cooperation and Development (OECD) are expected to capture most apical effects resulting from GM disruptions, exclusion of GM in the risk assessment might mischaracterize hazards or overestimate/underestimate risks, especially when extrapolating results from one species to another species or population with a substantially different GM. On the other hand, direct assessment of GM-mediated effects may face challenges in identifying hazards, since not all GM perturbations will lead to human adverse effects. In this regard, reliable and validated biomarkers for common GM-mediated adverse effects may be very useful in the identification of GM-mediated pesticide toxicity. Nevertheless, proving causality of GM-mediated effects will need modifications of Bradford Hill criteria as well as Koch's postulates, which are more suitable for the "one-pathogen" paradigm. Furthermore, risk assessment of GM-mediated effects may require pesticide toxicokinetics along the gut, possibly through modeling, and the establishment of the involvement of GM in the mechanism of action (MOA) of the pesticide. Risk assessment of GM mediated effects also requires the standardization of experimental approaches as well as the establishment of microbial reference communities, since variations exist among GM in human populations.

B-cell activating factor (BAFF) expression is associated with Crohn's disease and can serve as a potential prognostic indicator of disease response to Infliximab treatment

BACKGROUND

Several studies correlated elevated B-cell activating factor (BAFF) levels and its polymorphisms (SNPs) in patients with autoimmunity. Limited data existed regarding the role of BAFF in Crohn's Disease (CD) susceptibility and/or treatment response to infliximab.

AIM

This study aims to evaluate BAFF expression in CD patients, investigate if its expression can predict response to infliximab treatment, and examine the association of BAFF SNPs with CD susceptibility.

METHODS

One hundred twelve CD patients and 164 healthy controls were recruited. Serum BAFF levels were determined using an enzyme-linked immunosorbent assay. Participants were genotyped for rs9514828, rs1041569 and rs2893321 SNPs.

RESULTS

Serum BAFF concentration was elevated in CD patients (472.86 ± 223.60 pg/ml) compared with controls (128.16 ± 70.10 pg/ml) before treatment. Responders to IFX treatment had increased serum BAFF levels at baseline (610.03 ± 167.55 pg/ml) compared to non-responders (267.09 ± 107 pg/ml). In responders, BAFF concentration reduced after IFX administration, while increased in non-responders. The rs1041569, TA and AA genotypes frequencies, and the minor allele A were increased significantly in CD patients, indicating an association of the SNP with CD susceptibility.

CONCLUSIONS

Our study suggests that BAFF could be a potential biomarker of CD, while SNP rs1041569 was associated with CD susceptibility.

No interplay between gut microbiota composition and the lipopolysaccharide-induced innate immune response in humans in vivo

Objective

Animal studies have demonstrated the extensive interplay between the gut microbiota and immunity. Moreover, in critically ill patients, who almost invariably suffer from a pronounced immune response, a shift in gut microbiota composition is associated with infectious complications and mortality. We examined the relationship between interindividual differences in gut microbiota composition and variation in the in vivo cytokine response induced by bacterial lipopolysaccharide (LPS). Furthermore, we evaluated whether an LPS challenge alters the composition of the gut microbiota.

Methods

Healthy male volunteers received an intravenous bolus of 2 ng kg⁻¹ LPS (n = 70) or placebo (n = 8). Serial plasma concentrations of tumor necrosis factor‐α, interleukin (IL)‐6, IL‐8 and IL‐10 were measured, and subjects were divided into high and low cytokine responders. Gut microbiota composition was determined using 16s RNA gene sequencing of faecal samples obtained 1 day before (baseline) and 1 day and 7 days following the LPS challenge.

Results

Baseline microbiota composition, analysed by principal coordinate analysis and random forest analysis, did not differ between high and low responders for any of the four measured cytokines. Furthermore, baseline microbiota diversity (Shannon and Chao indices) was similar in high and low responders. No changes in microbiota composition or diversity were observed at 1 and 7 days following the LPS challenge.

Conclusion

Our results indicate that existing variation in gut microbiota composition does not explain the observed variability in the LPS‐induced innate immune response. These findings strongly argue against the interplay between the gut microbiota composition and the innate immune response in humans.

Growth-promoting effect of alginate on Faecalibacterium prausnitzii through cross-feeding with Bacteroides

Faecalibacterium prausnitzii is a commensal gut bacterium that is thought to provide protection against inflammatory diseases. However, this bacterium is extremely oxygen sensitive, which limits its industrial application as a probiotic. The use of prebiotics to increase the abundance of this bacterium in the gut is an alternative strategy to achieve its possible health-promoting effect. We evaluated nine substances as candidate prebiotics for F. prausnitzii using a pH-controlled single-batch fermenter as a human gut microbiota model. Of them, alginate markedly increased the relative abundance of F. prausnitzii, as determined by the significant increase in the number of 16S rRNA sequences corresponding to this bacterial taxon in the fecal fermentation samples detected by real-time PCR. However, F. prausnitzii strains were incapable of utilizing alginate in monoculture, implying that an interaction with another gut microbe was required. There was a positive correlation between the relative abundance of F. prausnitzii and that of Bacteroides when cultured in medium containing alginate as the sole carbon source, indicative of cross-feeding between these bacteria. Interestingly, the ratio of acetic acid, a known substrate for F. prausnitzii, produced by Bacteroides was significantly higher in the alginate-containing medium than in media containing other prebiotic candidates. Bacterially degraded alginate oligosaccharides (AOS) remained in the medium after Bacteroides monoculture, and an isolate of F. prausnitzii was able to utilize a portion of them. Genomic sequencing revealed that the strain that consumed the AOS contained an ATP-binding cassette transporter, an alginate lyase, and AlgQ1/2 homologs encoding solute-binding proteins. Furthermore, in real-time PCR analyses, AlgQ1/2 homologs were detected in fecal samples collected from 309 of 452 (68.4%) Japanese subjects. Thus, the products of alginate assimilation by Bacteroides may promote the growth of F. prausnitzii.

Trends in Incidence of Autoimmune Liver Diseases and Increasing Incidence of Autoimmune Hepatitis

BACKGROUND & AIMS

Autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) are autoimmune liver diseases of unknown etiology. We studied trends in incidences of AIH, PBC, and PSC in a population-based prospective study Canterbury, New Zealand.

METHODS

We collected data on patients with AIH (n = 99), PBC (n = 26), or PSC (n = 47) from public hospitals and private practices in Canterbury from 2008 through 2016. Diagnoses were made based on international standardized criteria. We calculated incidence rates for the time periods of 2008-2010, 2011-2013, and 2014-2016 and compared them using 2-tailed mid-P exact tests.

RESULTS

Overall incidence rates were 1.93 per 100,000 for AIH (95% CI, 1.58-2.34), 0.51 per 100,000 for PBC (95% CI, 0.33-0.73), and 0.92 per 100,000 for PSC (95% CI, 0.68-1.21). The incidence of AIH was significantly higher during the period of 2014-2016 (2.39 per 100,000; 95% CI, 1.76-3.23) than during the period of 2008-2010 (1.37 per 100,000; 95% CI, 0.91- 2.06) (P < .05). Incidences of PBC and PSC did not change significantly. In 2016, prevalence values were 27.4 per 100,000 for AIH (95% CI, 23.58-32.0), 9.33 per 100,000 for PBC (95% CI, 7.13-12.05), and 13.17 per 100,000 for PSC (95% CI, 10.56-16.42).

CONCLUSIONS

In a population-based prospective study, we found that the incidence of AIH was significantly higher in the 2014-2016 period than the 2008-2010 period; incidences of PBC and PSC were unchanged over the same period. Further studies are needed to determine the reasons for changes in incidence of autoimmune liver diseases.

Human β-Defensin 2 Mutations Are Associated With Asthma and Atopy in Children and Its Application Prevents Atopic Asthma in a Mouse Model

Asthma and allergies are complex, chronic inflammatory diseases in which genetic and environmental factors are crucial. Protection against asthma and allergy development in the context of farming environment is established by early animal contact, unpasteurized milk consumption and gut microbiota maturation. The human β-defensin 2 (hBD-2) is a host defense peptide present almost exclusively in epithelial tissues, with pronounced immunomodulatory properties, which has recently been shown to ameliorate asthma and IBD in animal models. We hypothesized that adequate hBD-2 secretion plays a role in the protection against asthma and allergy development and that genetic variations in the complex gene locus coding for hBD-2 may be a risk factor for developing these diseases, if as a consequence, hBD-2 is insufficiently produced. We used MALDI-TOF MS genotyping, sequencing and a RFLP assay to study the genetic variation including mutations, polymorphisms and copy number variations in the locus harboring both genes coding for hBD-2 (DEFB4A and DEFB4B). We administered hBD-2 orally in a mouse model of house dust mite (HDM)-asthma before allergy challenge to explore its prophylactic potential, thereby mimicking a protective farm effect. Despite the high complexity of the region harboring DEFB4A and DEFB4B we identified numerous genetic variants to be associated with asthma and allergy in the GABRIELA Ulm population of 1,238 children living in rural areas, including rare mutations, polymorphisms and a lack of the DEFB4A. Furthermore, we found that prophylactic oral administration of hBD-2 significantly curbed lung resistance and pulmonary inflammation in our HDM mouse model. These data indicate that inadequate genetic capacity for hBD-2 is associated with increased asthma and allergy risk while adequate and early hBD-2 administration (in a mouse model) prevents atopic asthma. This suggests that hBD-2 could be involved in the protective farm effect and may be an excellent candidate to confer protection against asthma development.

Reflections on the Use of an Invertebrate Chordate Model System for Studies of Gut Microbial Immune Interactions

The functional ecology of the gastrointestinal tract impacts host physiology, and its dysregulation is at the center of various diseases. The immune system, and specifically innate immunity, plays a fundamental role in modulating the interface of host and microbes in the gut. While humans remain a primary focus of research in this field, the use of diverse model systems help inform us of the fundamental principles legislating homeostasis in the gut. Invertebrates, which lack vertebrate-style adaptive immunity, can help define conserved features of innate immunity that shape the gut ecosystem. In this context, we previously proposed the use of a marine invertebrate, the protochordate Ciona robusta, as a novel tractable model system for studies of host-microbiome interactions. Significant progress, reviewed herein, has been made to fulfill that vision. We examine and review discoveries from Ciona that include roles for a secreted immune effector interacting with elements of the microbiota, as well as chitin-rich mucus lining the gut epithelium, the gut-associated microbiome of adults, and the establishment of a large catalog of cultured isolates with which juveniles can be colonized. Also discussed is the establishment of methods to rear the animals germ-free, an essential technology for dissecting the symbiotic interactions at play. As the foundation is now set to extend these studies into the future, broadening our comprehension of how host effectors shape the ecology of these microbial communities in ways that establish and maintain homeostasis will require full utilization of "multi-omics" approaches to merge computational sciences, modeling, and experimental biology in hypothesis-driven investigations.

Sharing CD4+ T Cell Loss: When COVID-19 and HIV Collide on Immune System

COVID-19 is a distinctive infection characterized by elevated inter-human transmission and presenting from absence of symptoms to severe cytokine storm that can lead to dismal prognosis. Like for HIV, lymphopenia and drastic reduction of CD4+ T cell counts in COVID-19 patients have been linked with poor clinical outcome. As CD4+ T cells play a critical role in orchestrating responses against viral infections, important lessons can be drawn by comparing T cell response in COVID-19 and in HIV infection and by studying HIV-infected patients who became infected by SARS-CoV-2. We critically reviewed host characteristics and hyper-inflammatory response in these two viral infections to have a better insight on the large difference in clinical outcome in persons being infected by SARS-CoV-2. The better understanding of mechanism of T cell dysfunction will contribute to the development of targeted therapy against severe COVID-19 and will help to rationally design vaccine involving T cell response for the long-term control of viral infection.