Immunoglobulin A, an Active Liaison for Host-Microbiota Homeostasis

Analysis of gut microbiota variations in patients with Henoch-Schönlein purpura: a comprehensive systematic review

OBJECTIVE

The primary purpose of our study was to perform a comprehensive systematic review, aiming to bring out the association between gut microbiota, Henoch-Schönlein Purpura (HSP) and Henoch-Schönlein nephritis (HSPN) patients.

METHODS

A systematic review was performed using five electronic databases, including Medline (through PubMed), Scopus, Embase, Cochrane, and Web of Science, from inspection up to March 21, 2024, to detect the studies that assessed the gut microbiota variation in Henoch-Schönlein Purpura (HSP) and Henoch-Schönlein nephritis (HSPN) patients.

RESULTS

Microbial diversity, richness, and composition in HSP patients are decreased compared to the healthy control group. In addition, HSP patients display a different microbiota structure and show a significant difference in taxonomic abundance between HSP and health control, which differs from one level to another. At the phylum level, Bacteroidetes, Fusobacteria, and Blastocladiomycota were more abundant; at the class level, Bacteroidetes were more abundant; at the order level, Bacteroidetes were more abundant in the HSP group-stage and site of HSP involvement effect on microbiota. Gastrointestinal tract involvement is characterized by increased abundance of Streptococcus and Fusobacteria and a decrease in Faecalibacterium. Kidney involvement is characterized by increased abundance of Streptococcus spp, which can be used as an indicator of disease severity. Escherichia-Shigella can be used as a diagnostic for the recurrence of HSP because its abundance is higher than primary HSP.

CONCLUSION

Gut microbiota can be utilized to assess the severity, recurrence, and site of HSP infection by analyzing the diversity, richness, and abundance of specific microorganisms associated with the condition.

New thoughts on the intestinal microbiome-B cell-IgA axis and therapies in IgA nephropathy

IgA nephropathy (IgAN), as the most common chronic glomerulonephritis worldwide, is often triggered by mucosal infections and follows a chronic progression, with the majority of patients ultimately progressing to end-stage renal disease (ESRD) during their lifetimes. Since the mystery of its complete pathogenesis has not been fully solved, the resulting lack of effective early diagnosis and treatment greatly affects the prognosis of patients. Given the well-defined pathological feature of IgA deposition in the mesangial region, the source and role of pathogenic IgA has been focused on. Starting from the microbiology and immunity of the gut, we systematically review both the physiological and the pathological process of microbiome-B cell-IgA axis, from microbial-induced IgA production to the role of IgA in the intestinal immune milieu, and ultimately end up with the various aspects of microbiome-B cell-IgA axis in the pathogenesis of IgAN as well as the corresponding therapeutic initiatives available. Our retrospective review helps researchers to systematically understand the complex role between intestinal flora dysbiosis and pathogenic IgA in IgAN. This understanding provides a foundation for in-depth explorations to uncover more detailed pathogenic mechanisms and to develop more precise and effective diagnostic and therapeutic approaches.

Intestinal immunoglobulins under microbial dysbiosis: implications in opioid-induced microbial dysbiosis

Intestinal immunoglobulins (Igs) maintain homeostasis between the microbiome and host. IgA facilitates microbial balance through a variety of increasingly well-described mechanisms. However, IgM and IgG have less defined intestinal functions but have the potential to activate clearance mechanisms such as the complement system and receptor-mediated bacterial killing. Very little is known regarding the role of Igs under microbial dysbiosis. In this review, we explore how Igs sculpt the intestinal microbiome and respond to microbial dysbiosis. We discuss how IgM, IgA, IgG, and complement individually maintain harmony with the microbiome and consider how these mechanisms could work in synergy. Finally, we explore using an opioid-induced microbial dysbiosis as a model to elucidate immediate changes in Ig-bacterial interactions.

Exploring and evaluating microbiome resilience in the gut

The gut ecosystem is closely related to human gastrointestinal health and overall wellness. Microbiome resilience refers to the capability of a microbial community to resist or recover from perturbations to its original state of balance. So far, there is no consensus on the criteria for assessing microbiome resilience. This article provides new insights into the metrics and techniques for resilience assessment. We discussed several potential parameters, such as microbiome structure, keystone species, biomarkers, persistence degree, recovery rate, and various research techniques in microbiology, metagenomics, biochemistry, and dynamic modeling. The article further explores the factors that influence the gut microbiome resilience. The microbiome structure (i.e. abundance and diversity), keystone species, and microbe-microbe interplays determine microbiome resilience. Microorganisms employ a variety of mechanisms to achieve the microbiome resilience, including flexible metabolism, quorum sensing, functional redundancy, microbial cooperation, and competition. Host-microbe interactions play a crucial role in maintaining microbiome stability and functionality. Unlike other articles, we focus on the regulation of host immune system on microbiome resilience. The immune system facilitates bacterial preservation and colonization, community construction, probiotic protection, and pathogen elimination through the mechanisms of immunological tolerance, immune-driven microbial compartmentalization, and immune inclusion and exclusion. Microbial immunomodulation indirectly modulates microbiome resilience.

Strain- and vaccine-specific effects of serum antibodies in the protection of intestinal SARS-CoV-2 infection

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection remains a public health challenge worldwide. The gastrointestinal tract has emerged as an important site of infection and has been implicated as a reservoir for long-term infection, particularly for post-acute COVID-19 syndrome. However, whether vaccine-induced systemic antibodies can prevent intestinal infection with SARS-CoV-2 is unclear. Compared to Vero cells commonly used to assess SARS-CoV-2 neutralization, the intestinal epithelium has a functional interferon response and expresses higher levels of ACE2, enzymes, and antibody-binding Fc receptors that may impact SARS-CoV-2 immune elimination.

Methods

We evaluated the potential of antibodies from both naturally infected and vaccinated human subjects to inhibit SARS-CoV-2 infection of the intestinal epithelium. Serum samples were collected from human volunteers who had undergone natural infection with SARS-CoV-2 in 2020 (n=5) or who had received the Pfizer BNT162b2 COVID-19 vaccine (n=13). Banked sera collected in 2016 served as negative controls (n=2). SARS-CoV-2 (WA01, Delta or Omicron) was pre-treated with sera and then used to infect iPSC-derived human intestinal organoids (HIO) or Caco-2 colonic epithelial cells, and SARS-CoV-2 infection was quantified by plaque assay, PCR, or immunofluorescence (IF) after 48-96 h.

Results

Both HIOs and Caco-2 cells supported robust infection with SARS-CoV-2. In HIOs, pretreatment of SARS-CoV-2 with a high titer post-vaccine serum completely blocked replication of WA01. Similarly, sera from both naturally infected donors collected in 2020 and sera from individuals who had received a BNT162b2 vaccine significantly inhibited replication of the WA01 strain in Caco-2 cells. In contrast, none of the sera significantly inhibited infection with the Delta variant of SARS-CoV-2. For Omicron, only sera from individuals who had received an Omicron-based vaccine significantly inhibited infection with SARS-CoV-2 in the plaque assay. Across all virus types, sera from individuals who had received Omicron-based BNT162b2 boosters were the most effective at reducing infection in Caco-2 cells.

Conclusion

Our results suggest that vaccine-induced antibody responses to SARS-CoV-2 are protective in the gut. Our study also supports previous reports indicating that SARS-CoV-2 vaccines need to be adapted to circulating virus strains to convey full protection from infection.

Bioactive nanomotor enabling efficient intestinal barrier penetration for colorectal cancer therapy

Oral drug delivery systems had natural potential for colorectal cancer drug therapy. While the drug delivery efficiency is severely hindered by the complex intestinal barriers, especially mucus and epithelium barriers, resulting in unsatisfactory therapeutic effects and limited clinical translation. In this work, a bioactive self-thermophoretic and gas dual-driven nanomotor is developed for colorectal cancer therapy through efficient intestinal mucus and epithelial barrier penetration. The nanomotor shows intestinal mucus barrier penetration and the paracellular pathway reversibly opening properties of intestinal epithelium barrier, increasing the delivery efficiency of cisplatin by 3.5 folds. Owing to the targeted delivery of cisplatin and the reduced side effects on normal intestinal tissues, the therapeutic efficiency of the nanomotor for colorectal cancer in vivo is as high as 98.6%. With autonomous and reversible intestinal barriers penetration property, the nanoplatform may innovate the current oral drug delivery.

Deoxynivalenol mycotoxin dietary exposure on broiler performance and small intestine health: A comprehensive meta-analysis

The effect of DON mycotoxins on broiler production performance and the small intestine is a critical factor in the health and well-being of broilers. Several studies have been conducted on this topic and have reported varying results and conclusions. Therefore, it is necessary to conduct systematic reviews and meta-analyses to thoroughly examine and draw unique conclusions. In this meta-analysis, we conducted a systematic review of multiple studies on the effects of DON mycotoxins in broilers. The analysis comprised 26 articles from reputable journals, and 14 parameters were identified based on the predetermined criteria. The forest plot results showed that DON treatment significantly reduced the ADFI and ADWG (SMD-1.50, 95 %CI [-1.68, -1.18]; I2= 51 %; p < 0.00001) and affected FCR (SMD 0.95, 95 %CI [ 0.62, 1.28]; I2= 77; p < 0.00001). In addition, it affects the small intestine structure duodenum (SMD -3.46, 95 %CI [-3.88, -3.05]; I2= 48 %; p < 0.00001), Jejunum (SMD -5.35, 95 %CI [-5.86, -4.83]; I2= 62 %; p < 0.00001), Ileum (SMD -2.6, 95 % CI [-3.12, -2.08]; I2= 82 %; p < 0.00001). Furthermore, DON exposure affects immunoglobulin (SMD -1.92, 95 % CI [ -2.39, -1.46]; I2 = 54 %; p < 0.00001) and antioxidant activities (SMD -2.1, 95 % CI [ -2.45, -1.75]; I2= 47 %; p < 0.00001). The overall effect of DON treatment was statistically significant compared with that of the control group. Furthermore, funnel plot analysis for publication bias did not reveal any significant asymmetry in most included studies. The results of this meta-analysis indicate that DON mycotoxins have a significant impact on both production performance and small intestine health and require strategic intervention.

Effect of food derived bioactive peptides on gut health and inflammatory mediators in vivo: a systematic review

Dietary proteins serve as sources of exogenous peptides, after being released from the protein and absorbed, the bioactive peptides can perform several functions in the body. The objective of the current systematic review is to answer the question "How does food derived bioactive peptides can impact on gut health and inflammatory mediators in vivo?" The search was performed at PubMed, Cochrane, and Scopus databases for experimental studies, and the risk of bias was assessed by the SYRCLE tool. The data analysis was conducted following the PRISMA guidelines. Eleven studies performed in animal models evaluating bioactive peptides derived from animal and plant sources were included and evaluated for limitations in heterogeneity, methodologies, absence of information regarding the allocation process, and investigators' blinding. The bioactive peptides demonstrated potential positive effects on inflammation and gut health. The main results identified were a reduction in TNF-α, NF-κB, and TLR4, an improvement in IgA production and in intestinal morphology, with an increase in villi surface area and goblet cell diameter, and Shannon and Simpson indexes were also increased. However, more in vivo studies are still necessary to better elucidate the anti-inflammatory activity and mechanisms by which peptides regulate gut health. PROSPERO (CRD42023416680).

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

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

Bioprospecting and Exploration of Phytochemicals as Quorum Sensing Inhibitors against Cariogenic Dental Biofilm

Dental caries is a polymicrobial infection affecting the dental hard tissues. Excessive carbohydrate intake leads to the accumulation of acid-producing and acid-resistant microorganisms in the oral region. It is a biofilm-dependent oral infection with cariogenic pathogens and the most prevalent disease globally. The prevention and control of caries play a vital role in global health management. Periodontal diseases and subgingival plaque etiology are due to the combined action of bacterial invasion and immune reaction, resulting in the devastation of periodontal tissues, culminating in tooth loss. The compact micro colony inhabiting the dental surfaces attaches with secreted polymer, forming a biofilm. Bacterial biofilm impervious to various drugs and chemicals poses a significant challenge in therapeutic scenarios of medical and odonatological infections. The quorum-sensing signaling mechanism in bacteria controls the metabolic and physiologic properties involved in bacterial existence, pathogenesis, and virulence. Hence, studies monitoring the molecular mechanism of quorum sensing and their restricted social interactions will be highly beneficial in the treatment regimen of the modern era. Natural bioactive compounds can be exploited for their medicinal value in combating oro-dental infections. Phytochemicals are promising candidates that could provide novel strategies for fighting infections. The current review highlights the mechanism of quorum sensing, plant products’ effect in controlling quorum sensing, and biofilm-induced dental infections like Periodontitis.

Unmasking the potential of secretory IgA and its pivotal role in protection from respiratory viruses

Mucosal immunity has regained its spotlight amidst the ongoing Coronavirus disease 19 (COVID-19) pandemic, with numerous studies highlighting the crucial role of mucosal secretory IgA (SIgA) in protection against Severe acute respiratory syndrome coronavirus-2 or SARS-CoV-2 infections. The observed limitations in the efficacy of currently authorized COVID-19 vaccines in inducing effective mucosal immune responses remind us of the limitations of systemic vaccination in promoting protective mucosal immunity. This resurgence of interest has motivated the development of vaccine platforms capable of enhancing mucosal responses, specifically the SIgA response, and the development of IgA-based therapeutics. Recognizing viral respiratory infections as a global threat, we would like to comprehensively review the existing knowledge on mucosal immunity, with a particular emphasis on SIgA, in the context of SARS-CoV-2, influenza, and Respiratory Syncytial Virus (RSV) infections. This review aims to describe the structural and functional specificities of SIgA, along with its nuanced role in combating influenza, RSV, and SARS-CoV-2 infections. Subsequent sections further elaborate promising vaccine strategies, including mucosal vaccines against Influenza, RSV, and SARS-CoV-2 respiratory viruses, currently undergoing preclinical and clinical development. Additionally, we address the challenges associated with mucosal vaccine development, concluding with a discussion on IgA-based therapeutics as a promising platform for the treatment of viral respiratory infections. This comprehensive review not only synthesizes current insights into mucosal immunity but also identifies critical knowledge gaps, strengthening the way for further advancements in our current understanding and approaches to combat respiratory viral threats.

Increasing taxonomic and functional characterization of host-microbiome interactions by DIA-PASEF metaproteomics

Introduction

Metaproteomics is a rapidly advancing field that offers unique insights into the taxonomic composition and the functional activity of microbial communities, and their effects on host physiology. Classically, data-dependent acquisition (DDA) mass spectrometry (MS) has been applied for peptide identification and quantification in metaproteomics. However, DDA-MS exhibits well-known limitations in terms of depth, sensitivity, and reproducibility. Consequently, methodological improvements are required to better characterize the protein landscape of microbiomes and their interactions with the host.

Methods

We present an optimized proteomic workflow that utilizes the information captured by Parallel Accumulation-Serial Fragmentation (PASEF) MS for comprehensive metaproteomic studies in complex fecal samples of mice.

Results and discussion

We show that implementing PASEF using a DDA acquisition scheme (DDA-PASEF) increased peptide quantification up to 5 times and reached higher accuracy and reproducibility compared to previously published classical DDA and data-independent acquisition (DIA) methods. Furthermore, we demonstrate that the combination of DIA, PASEF, and neuronal-network-based data analysis, was superior to DDA-PASEF in all mentioned parameters. Importantly, DIA-PASEF expanded the dynamic range towards low-abundant proteins and it doubled the quantification of proteins with unknown or uncharacterized functions. Compared to previous classical DDA metaproteomic studies, DIA-PASEF resulted in the quantification of up to 4 times more taxonomic units using 16 times less injected peptides and 4 times shorter chromatography gradients. Moreover, 131 additional functional pathways distributed across more and even uniquely identified taxa were profiled as revealed by a peptide-centric taxonomic-functional analysis. We tested our workflow on a validated preclinical mouse model of neuropathic pain to assess longitudinal changes in host-gut microbiome interactions associated with pain - an unexplored topic for metaproteomics. We uncovered the significant enrichment of two bacterial classes upon pain, and, in addition, the upregulation of metabolic activities previously linked to chronic pain as well as various hitherto unknown ones. Furthermore, our data revealed pain-associated dynamics of proteome complexes implicated in the crosstalk between the host immune system and the gut microbiome. In conclusion, the DIA-PASEF metaproteomic workflow presented here provides a stepping stone towards a deeper understanding of microbial ecosystems across the breadth of biomedical and biotechnological fields.

The interaction between autophagy, Helicobacter pylori, and gut microbiota in gastric carcinogenesis

Chronic infection with Helicobacter pylori is the primary risk factor for the development of gastric cancer. Hindering our ability to comprehend the precise role of autophagy during H. pylori infection is the complexity of context-dependent autophagy signaling pathways. Recent and ongoing progress in understanding H. pylori virulence allows new frontiers of research for the crosstalk between autophagy and H. pylori. Novel approaches toward discovering autophagy signaling networks have further revealed their critical influence on the structure of gut microbiota and the metabolome. Here we intend to present a holistic view of the perplexing role of autophagy in H. pylori pathogenesis and carcinogenesis. We also discuss the intermediate role of autophagy in H. pylori-mediated modification of gut inflammatory responses and microbiota structure.

The Underappreciated Role of Secretory IgA in IBD

Eighty percent of antibody secreting cells (ASCs) are found in the intestine, where they produce grams of immunoglobulin (Ig) A daily. immunoglobulin A is actively transcytosed into the lumen, where it plays a critical role in modulating the gut microbiota. Although loss of immune tolerance to bacterial antigens is the likely trigger of the dysregulated immune response that characterizes inflammatory bowel disease (IBD), little effort has been placed on understanding the interface between B cells, IgA, and the microbiota during initiation or progression of disease. This may be in part due to the misleading fact that IgA-deficient humans are mostly asymptomatic, likely due to redundant role of secretory (S) IgM. Intestinal B cell recruitment is critically dependent on integrin α4β7-MAdCAM-1 interactions, yet antibodies that target α4β7 (ie, vedolizumab), MAdCAM-1 (ie, ontamalimab), or both β7 integrins (α4β7 and αE [CD103] β7; etrolizumab) are in clinical use or development as IBD therapeutics. The effect of such interventions on the biology of IgA is largely unknown, yet a single dose of vedolizumab lowers SIgA levels in stool and weakens the oral immunization response to cholera vaccine in healthy volunteers. Thus, it is critical to further understand the role of these integrins for the migration of ASC and other cellular subsets during homeostasis and IBD-associated inflammation and the mode of action of drugs that interfere with this traffic. We have recently identified a subset of mature ASC that employs integrin αEβ7 to dock with intestinal epithelial cells, predominantly in the pericryptal region of the terminal ileum. This role for the integrin had not been appreciated previously, nor the αEβ7-dependent mechanism of IgA transcytosis that it supports. Furthermore, we find that B cells more than T cells are critically dependent on α4β7-MAdCAM-1 interactions; thus MAdCAM-1 blockade and integrin-β7 deficiency counterintuitively hasten colitis in interleukin-10-deficient mice. In both cases, de novo recruitment of IgA ASC to the intestinal lamina propria is compromised, leading to bacterial overgrowth, dysbiosis, and lethal colitis. Thus, despite the safe and effective use of anti-integrin antibodies in patients with IBD, much remains to be learned about their various cell targets.

Microbial Reprogramming in Obsessive-Compulsive Disorders: A Review of Gut-Brain Communication and Emerging Evidence

Obsessive-compulsive disorder (OCD) is a debilitating mental health disorder characterized by intrusive thoughts (obsessions) and repetitive behaviors (compulsions). Dysbiosis, an imbalance in the gut microbial composition, has been associated with various health conditions, including mental health disorders, autism, and inflammatory diseases. While the exact mechanisms underlying OCD remain unclear, this review presents a growing body of evidence suggesting a potential link between dysbiosis and the multifaceted etiology of OCD, interacting with genetic, neurobiological, immunological, and environmental factors. This review highlights the emerging evidence implicating the gut microbiota in the pathophysiology of OCD and its potential as a target for novel therapeutic approaches. We propose a model that positions dysbiosis as the central unifying element in the neurochemical, immunological, genetic, and environmental factors leading to OCD. The potential and challenges of microbial reprogramming strategies, such as probiotics and fecal transplants in OCD therapeutics, are discussed. This review raises awareness of the importance of adopting a holistic approach that considers the interplay between the gut and the brain to develop interventions that account for the multifaceted nature of OCD and contribute to the advancement of more personalized approaches.

Effect of chia flour associated with high fat diet on intestinal health in female ovariectomized Wistar rats

PURPOSE

The present study aimed to evaluate the effect of chia flour associated with a high fat diet on intestinal health in female ovariectomized Wistar rats.

METHODS

The study was conducted with 32 adult female ovariectomized Wistar rats, which were separated into four groups: standard diet (ST), standard diet with chia (STC), high fat diet (HF) and high fat diet with chia (HFC) for 18 weeks. Cecum content pH, short chain fatty acid content, brush border membrane functionality and morphology and the gut microbiota were evaluated.

RESULTS

This study demonstrated that the consumption of chia flour increased the production of acetic and butyric acids, the longitudinal and circular muscle layers and crypt thickness. It also improved the expression of aminopeptidase (AP) and sucrose-isomaltase (SI) and decreased the cecum content pH. Further, the consumption of chia improved richness and decreased diversity of the microbiota. Operational Taxonomic Units (OTUs) clustering indicated difference between the ST and STC groups. In the linear discriminant analysis effect size (LEfSe) analysis, the Bacteroides genus and members of the Muribaculaceae and Lachnospiraceae families were enriched in the STC treatment group. The STC group demonstrated the enrichment of Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways related to peptidoglycan and coenzyme A biosynthesis.

CONCLUSION

Our results suggest that chia flour, which is rich in dietary fiber and phenolic compounds, presented potential properties to improve intestinal health.

Crosstalk between Gut Microbiota and Host Immunity: Impact on Inflammation and Immunotherapy

Gut microbes and their metabolites are actively involved in the development and regulation of host immunity, which can influence disease susceptibility. Herein, we review the most recent research advancements in the gut microbiota-immune axis. We discuss in detail how the gut microbiota is a tipping point for neonatal immune development as indicated by newly uncovered phenomenon, such as maternal imprinting, in utero intestinal metabolome, and weaning reaction. We describe how the gut microbiota shapes both innate and adaptive immunity with emphasis on the metabolites short-chain fatty acids and secondary bile acids. We also comprehensively delineate how disruption in the microbiota-immune axis results in immune-mediated diseases, such as gastrointestinal infections, inflammatory bowel diseases, cardiometabolic disorders (e.g., cardiovascular diseases, diabetes, and hypertension), autoimmunity (e.g., rheumatoid arthritis), hypersensitivity (e.g., asthma and allergies), psychological disorders (e.g., anxiety), and cancer (e.g., colorectal and hepatic). We further encompass the role of fecal microbiota transplantation, probiotics, prebiotics, and dietary polyphenols in reshaping the gut microbiota and their therapeutic potential. Continuing, we examine how the gut microbiota modulates immune therapies, including immune checkpoint inhibitors, JAK inhibitors, and anti-TNF therapies. We lastly mention the current challenges in metagenomics, germ-free models, and microbiota recapitulation to a achieve fundamental understanding for how gut microbiota regulates immunity. Altogether, this review proposes improving immunotherapy efficacy from the perspective of microbiome-targeted interventions.

Microbiota of the gastrointestinal tract: Friend or foe?

The gut microbiota is currently considered an external organ of the human body that provides important mechanisms of metabolic regulation and protection. The gut microbiota encodes over 3 million genes, which is approximately 150 times more than the total number of genes present in the human genome. Changes in the qualitative and quantitative composition of the microbiome lead to disruption in the synthesis of key bacterial metabolites, changes in intestinal barrier function, and inflammation and can cause the development of a wide variety of diseases, such as diabetes, obesity, gastrointestinal disorders, cardiovascular issues, neurological disorders and oncological concerns. In this review, I consider issues related to the role of the microbiome in the regulation of intestinal barrier function, its influence on physiological and pathological processes occurring in the body, and potential new therapeutic strategies aimed at restoring the gut microbiome. Herewith, it is important to understand that the gut microbiota and human body should be considered as a single biological system, where change of one element will inevitably affect its other components. Thus, the study of the impact of the intestinal microbiota on health should be considered only taking into account numerous factors, the role of which has not yet been fully elucidated.

Six Decades of History of Hypertension Research at the University of Toledo: Highlighting Pioneering Contributions in Biochemistry, Genetics, and Host-Microbiota Interactions

PURPOSE OF REVIEW

The study aims to capture the history and lineage of hypertension researchers from the University of Toledo in Ohio and showcase their collective scientific contributions dating from their initial discoveries of the physiology of adrenal and renal systems and genetics regulating blood pressure (BP) to its more contemporary contributions including microbiota and metabolomic links to BP regulation.

RECENT FINDINGS

The University of Toledo College of Medicine and Life Sciences (UTCOMLS), previously known as the Medical College of Ohio, has contributed significantly to our understanding of the etiology of hypertension. Two of the scientists, Patrick Mulrow and John Rapp from UTCOMLS, have been recognized with the highest honor, the Excellence in Hypertension award from the American Heart Association for their pioneering work on the physiology and genetics of hypertension, respectively. More recently, Bina Joe has continued their legacy in the basic sciences by uncovering previously unknown novel links between microbiota and metabolites to the etiology of hypertension, work that has been recognized by the American Heart Association with multiple awards. On the clinical research front, Christopher Cooper and colleagues lead the CORAL trials and contributed importantly to the investigations on renal artery stenosis treatment paradigms. Hypertension research at this institution has not only provided these pioneering insights, but also grown careers of scientists as leaders in academia as University Presidents and Deans of Medical Schools. Through the last decade, the university has expanded its commitment to Hypertension research as evident through the development of the Center for Hypertension and Precision Medicine led by Bina Joe as its founding Director. Hypertension being the top risk factor for cardiovascular diseases, which is the leading cause of human mortality, is an important area of research in multiple international universities. The UTCOMLS is one such university which, for the last 6 decades, has made significant contributions to our current understanding of hypertension. This review is a synthesis of this rich history. Additionally, it also serves as a collection of audio archives by more recent faculty who are also prominent leaders in the field of hypertension research, including John Rapp, Bina Joe, and Christopher Cooper, which are cataloged at Interviews .

Selective IgA Deficiency in Spontaneously Hypertensive Rats With Gut Dysbiosis

BACKGROUND

The spontaneously hypertensive rat (SHR) is extensively used to study hypertension. Gut microbiota dysbiosis is a notable feature in SHR for reasons unknown. Immunoglobulin A (IgA) is a major host factor required for gut microbiota homeostasis. We hypothesized that inadequate IgA contributes to gut microbiota dysbiosis in SHR.

METHODS

IgA was measured in feces, cecum, serum, liver, gut-associated lymphoid tissue, and milk from SHR and Wistar Kyoto rats. IgA regulatory factors like IgM, IgG, and pIgR (polymeric immunoglobulin receptor) were analyzed. IgA and IgG antibodies and blood pressure (BP) were measured before and after administrating a bacterial antigen (ie, flagellin).

RESULTS

Compared with Wistar Kyoto rats, SHR displayed remarkably near-deficient IgA levels accompanied by compensatory increases in serum IgM and IgG and gut-liver pIgR expression. Inadequate milk IgA in SHR emphasized this immune defect stemmed from the neonatal stage. Reduced IgA+ B cells in circulation and Peyer patches indicated a possible reason for the lower IgA in SHR. Noteworthy, a genetic insufficiency was unlikely because administering flagellin to SHR induced anti-flagellin IgA antibodies. This immune response surprisingly accelerated hypertension development in SHR, suggesting IgA quiescence may help maintain lower BP.

CONCLUSIONS

This study is the first to reveal IgA deficiency in SHR as one host factor associated with gut microbiota dysbiosis and invigorates future research to determine the pathophysiological role of IgA in hypertension.

B cells in autoimmune hepatitis: bystanders or central players?

B cells are central for the adaptive immune system to mount successful immune responses not only as antibody producers but also as regulators of cellular immunity. These multifaceted features are also reflected in autoimmunity where autoreactive B cells can fuel disease by production of cytotoxic autoantibodies, presentation of autoantigens to autoreactive T cells, and secretion of cytokines and chemokines that either promote detrimental immune activation or impair regulatory T and B cells. The role of B cells and autoantibodies in autoimmune hepatitis (AIH) have been controversially discussed, with typical autoantibodies and hypergammaglobulinemia indicating a key role, while strong HLA class II association suggests T cells as key players. In this review, we summarize current knowledge on B cells in AIH and how different B cell subpopulations may drive AIH progression beyond autoantibodies. We also discuss recent findings of B cell-directed therapies in AIH.

Dietary Brewer Grain Meal with Multienzymes Supplementation Affects Growth Performance, Gut Health, and Antioxidative Status of Weaning Pigs

We conducted a 28-day feeding study on 80 weaning pigs [(Landrace × Large White) × Duroc] to determine the effects of dietary inclusion with brewer’s grain meal (BGM) and multienzymes on their growth, intestinal health, and antioxidative status. Piglets were grouped by sex and initial BW and assigned to 20 pens with four pigs each. Treatments were a corn–soybean meal-based diet with either 0.1% multienzyme addition (PC) or without (NC), and two BGM compositions fortified with 0.1% multienzyme: 10% (BGM10) and 20% (BGM20). The overall body weight, average daily weight gain, and weight gain:feed ratio were significantly greater in pigs fed BGM20 than those fed the NC diet (p < 0.05). Moreover, the BGM diets significantly increased the digestibility of total ash and ether extract, glucose, total protein, immunoglobulin A, total antioxidant capacity, superoxide dismutase, heart and small intestine weights, villus height: crypt depth ratio (VH/CD), and Lactobacillus spp. count compared with the NC diet (p < 0.05). The diarrheal rate, blood urea nitrogen, malondialdehyde, duodenal crypt depth, and Salmonella spp. count were reduced in pigs fed the BGM-supplemented diet than those fed the NC diet (p < 0.05). The diarrheal rate (p = 0.010), ether extract digestibility (p = 0.044), total protein (p = 0.044), and duodenal villus height and VH/CD (p = 0.003 and p = 0.002, respectively) decreased quadratically with the increase in BGM supplementation. Overall, diets containing up to 20% BGM with multienzyme addition improved the nutrient utilization and intestinal health in weaning pigs by suppressing pathogenic bacterial growth without compromising the overall growth of the pigs.

Selective IgA Deficiency and Allergy: A Fresh Look to an Old Story

Selective IgA deficiency (SIgAD) is the most common human primary immune deficiency (PID). It is classified as a humoral PID characterized by isolated deficiency of IgA (less than 7 mg/dL but normal serum IgG and IgM) in subjects greater than 4 years of age. Intrinsic defects in the maturation of B cells and a perturbation of Th cells and/or cytokine signals have been hypothesized to contribute to SIgAD pathogenesis. The genetic basis of IgA deficiency remains to be clarified. Patients with SIgAD can be either asymptomatic or symptomatic with clinical manifestations including allergy, autoimmunity and recurrent infections mainly of the respiratory and gastrointestinal tract. Studies analyzing allergy on SIgAD patients showed prevalence up to 84%, supporting in most cases the relationship between sIgAD and allergic disease. However, the prevalence of allergic disorders may be influenced by various factors. Thus, the question of whether allergy is more common in SIgAD patients compared to healthy subjects remains to be defined. Different hypotheses support an increased susceptibility to allergy in subjects with SIgAD. Recurrent infections due to loss of secretory IgA might have a role in the pathogenesis of allergy, and vice versa. Perturbation of microbiota also plays a role. The aim of this review is to examine the association between SIgAD and atopic disease and to update readers on advances over time at this important interface between allergy and SIgAD.

The double-edged sword of probiotic supplementation on gut microbiota structure in Helicobacter pylori management

As Helicobacter pylori management has become more challenging and less efficient over the last decade, the interest in innovative interventions is growing by the day. Probiotic co-supplementation to antibiotic therapies is reported in several studies, presenting a moderate reduction in drug-related side effects and a promotion in positive treatment outcomes. However, the significance of gut microbiota involvement in the competence of probiotic co-supplementation is emphasized by a few researchers, indicating the alteration in the host gastrointestinal microbiota following probiotic and drug uptake. Due to the lack of long-term follow-up studies to determine the efficiency of probiotic intervention in H. pylori eradication, and the delicate interaction of the gut microbiota with the host wellness, this review aims to discuss the gut microbiota alteration by probiotic co-supplementation in H. pylori management to predict the comprehensive effectiveness of probiotic oral administration.Abbreviations: acyl-CoA- acyl-coenzyme A; AMP- antimicrobial peptide; AMPK- AMP-activated protein kinase; AP-1- activator protein 1; BA- bile acid; BAR- bile acid receptor; BCAA- branched-chain amino acid; C2- acetate; C3- propionate; C4- butyrate; C5- valeric acid; CagA- Cytotoxin-associated gene A; cAMP- cyclic adenosine monophosphate; CD- Crohn's disease; CDI- C. difficile infection; COX-2- cyclooxygenase-2; DC- dendritic cell; EMT- epithelial-mesenchymal transition; FMO- flavin monooxygenases; FXR- farnesoid X receptor; GPBAR1- G-protein-coupled bile acid receptor 1; GPR4- G protein-coupled receptor 4; H2O2- hydrogen peroxide; HCC- hepatocellular carcinoma; HSC- hepatic stellate cell; IBD- inflammatory bowel disease; IBS- irritable bowel syndrome; IFN-γ- interferon-gamma; IgA immunoglobulin A; IL- interleukin; iNOS- induced nitric oxide synthase; JAK1- janus kinase 1; JAM-A- junctional adhesion molecule A; LAB- lactic acid bacteria; LPS- lipopolysaccharide; MALT- mucosa-associated lymphoid tissue; MAMP- microbe-associated molecular pattern; MCP-1- monocyte chemoattractant protein-1; MDR- multiple drug resistance; mTOR- mammalian target of rapamycin; MUC- mucin; NAFLD- nonalcoholic fatty liver disease; NF-κB- nuclear factor kappa B; NK- natural killer; NLRP3- NLR family pyrin domain containing 3; NOC- N-nitroso compounds; NOD- nucleotide-binding oligomerization domain; PICRUSt- phylogenetic investigation of communities by reconstruction of unobserved states; PRR- pattern recognition receptor; RA- retinoic acid; RNS- reactive nitrogen species; ROS- reactive oxygen species; rRNA- ribosomal RNA; SCFA- short-chain fatty acids; SDR- single drug resistance; SIgA- secretory immunoglobulin A; STAT3- signal transducer and activator of transcription 3; T1D- type 1 diabetes; T2D- type 2 diabetes; Th17- T helper 17; TLR- toll-like receptor; TMAO- trimethylamine N-oxide; TML- trimethyllysine; TNF-α- tumor necrosis factor-alpha; Tr1- type 1 regulatory T cell; Treg- regulatory T cell; UC- ulcerative colitis; VacA- Vacuolating toxin A.

Role of B-Cell Activating Factor (BAFF) in Inflammatory Bowel Disease

As early commencement of inflammatory bowel disease (IBD) treatment has been shown to substantially improve outcomes, it is of utmost importance to make a timely diagnosis of this disease. Despite undisputed sensitivity of fecal calprotectin, the most widely accepted IBD biomarker, in discriminating between irritable bowel syndrome (IBS) and IBD, as well as recognized role in monitoring disease activity and response to therapy, perhaps the biggest setback of calprotectin use in IBD is lack of specificity. Therefore, an additional biomarker in IBD is warranted. B-cell activating factor (BAFF), a member of the tumor necrosis factor (TNF) superfamily, recently emerged as a viable candidate for this role. So far, overproduction of BAFF has been observed in various autoimmune diseases, most notably in systemic lupus erythematosus, where BAFF-inhibitor belimumab was approved for treatment. As BAFF levels were also shown to correlate with indices of IBD, in this review we aimed to summarize the current evidence with respect to the role of BAFF in diagnosis and assessing the activity of IBD, as well as putative therapeutic implications that may arise from exploring of this relation.