Host-microbiota interactions in the intestine

Glaucoma and the Human Microbiome

PURPOSE OF REVIEW

To explore a view of the human microbiome as an interconnected, functional, dynamic system that may be linked to the pathogenesis and progression of glaucoma.

METHODS

A literature review was undertaken that included publications from 1966 to 2023.

RESULTS

Bacterial lipopolysaccharides (LPS) activate toll-like receptors (TLR) and mediate the human immune response. The LPS-TLR4 pathway is a potential avenue for the ocular, gut, and oral microbiomes to interface and/or influence ocular disease. Studies of gut dysbiosis have shown that alterations in the healthy microbiota can predispose the host to immune-mediated inflammatory and neurodegenerative conditions, while oral and ocular surface dysbiosis has been correlated with glaucoma. While developmental exposure to commensal microflora has shown to be necessary for the autoimmune and neurodegenerative responses to elevated intraocular pressure to take place, commensal bacterial products like short-chain fatty acids have regulatory effects protective against glaucoma.

SUMMARY

Alterations to human microbiotas have been associated with changes in intestinal permeability, gene regulation, immune cell differentiation, and neural functioning, which may predispose the host to glaucoma. Select microbes have been highlighted for their potential contributions to glaucoma disease progression or protection, raising the potential for microbiota-based treatment modalities. Current topical glaucoma treatments may disrupt the ocular surface microbiota, potentially having ramifications on host health. Further study of the relationships between human microbiome and glaucoma is needed.

Immune pathogenesis of idiopathic granulomatous mastitis: from etiology toward therapeutic approaches

Idiopathic granulomatous mastitis (IGM) is a noncancerous, chronic inflammatory disorder of breast with unknown causes, posing significant challenges to the quality of life due to its high refractoriness and local aggressiveness. The typical symptoms of this disease involve skin redness, a firm and tender breast mass and mastalgia; others may include swelling, fistula, abscess (often without fever), nipple retraction, and peau d'orange appearance. IGM often mimics breast abscesses or malignancies, particularly inflammatory breast cancer, and is characterized by absent standardized treatment options, inconsistent patient response and unknown mechanism. Definite diagnosis of this disease relies on core needle biopsy and histopathological examination. The prevailing etiological theory suggests that IGM is an autoimmune disease, as some patients respond well to steroid treatment. Additionally, the presence of concurrent erythema nodosum or other autoimmune conditions supports the autoimmune nature of the disease. Based on current knowledge, this review aims to elucidate the autoimmune-favored features of IGM and explore its potential etiologies. Furthermore, we discuss the immune-mediated pathogenesis of IGM using existing research and propose immunotherapeutic strategies for managing this condition.

The role of intestinal microecology in inflammatory bowel disease and colorectal cancer: A review

Intestinal microecology is a dominant and complex microecological system in human body. Generally, intestinal microecosystem consists of normal symbiotic flora and its living environment (including intestinal epithelial tissue and intestinal mucosal immune system). Commensal flora is the core component of microecology. Both structures of intestinal mucosa and functions of immune system are essential to maintain homeostasis of intestinal microecosystem. Under normal conditions, intestinal microorganisms and intestinal mucosa coordinate with each other to promote host immunity. When certain factors in the intestine are altered, such as disruption of the intestinal barrier causing dysbiosis of the intestinal flora, the immune system of the host intestinal mucosa makes a series of responses, which leads to the development of intestinal inflammation and promotes colorectal cancer. In this review, to further understand the relationship between intestinal microecology and intestinal diseases, we systematically elaborate the composition of the intestinal mucosal immune system, analyze the relationship between intestinal flora and mucosal immune system, and the role of intestinal flora on intestinal inflammatory diseases and colorectal cancer.

Microbial sensing in the intestine

The gut microbiota plays a key role in host health and disease, particularly through their interactions with the immune system. Intestinal homeostasis is dependent on the symbiotic relationships between the host and the diverse gut microbiota, which is influenced by the highly co-evolved immune-microbiota interactions. The first step of the interaction between the host and the gut microbiota is the sensing of the gut microbes by the host immune system. In this review, we describe the cells of the host immune system and the proteins that sense the components and metabolites of the gut microbes. We further highlight the essential roles of pattern recognition receptors (PRRs), the G protein-coupled receptors (GPCRs), aryl hydrocarbon receptor (AHR) and the nuclear receptors expressed in the intestinal epithelial cells (IECs) and the intestine-resident immune cells. We also discuss the mechanisms by which the disruption of microbial sensing because of genetic or environmental factors causes human diseases such as the inflammatory bowel disease (IBD).

Effects of dietary zinc chloride hydroxide and zinc methionine on the immune system and blood profile of healthy adult horses and ponies

The effects of dietary zinc on the immune function of equines have not been evaluated in detail so far. In the present study, eight healthy adult ponies and two healthy adult horses were fed a diet supplemented with either zinc chloride hydroxide or zinc methionine in six feeding periods of four weeks each (according to maintenance zinc requirement, 120 mg zinc/kg dry matter, and 240 mg zinc/kg dry matter, for both dietary zinc supplements, respectively). All animals received the six diets, with increasing amounts of zinc chloride hydroxide in the feeding periods 1-3, and with increasing amounts of zinc methionine in the feeding periods 4-6. At the end of each feeding period, blood samples were collected for a blood profile and the measurement of selected immune variables. Increasing dietary zinc chloride hydroxide doses increased the glutathione concentrations in the erythrocyte concentrate and the glutathione peroxidase activity in the erythrocyte lysate, decreased the numbers of total leukocytes and granulocytes in the blood, and also decreased the interleukin-2 concentrations in the plasma of the animals. The dietary supplementation of increasing doses of zinc methionine enhanced the mitogen-stimulated proliferative activity of peripheral blood mononuclear cells, and decreased the glutathione concentrations in the erythrocyte concentrate and the glutathione peroxidase activity in the plasma of the animals. The percentage of blood monocytes with oxidative burst after in vitro stimulation with E. coli decreased with increasing dietary zinc concentrations, independently of the zinc compound used. The blood profile demonstrated effects of the zinc supplements on the red blood cells and the bilirubin metabolism of the horses and ponies, which require further investigation. Overall, high doses of dietary zinc modulate the equine immune system, for the most part also depending on the zinc compound used.

Gastrointestinal consequences of lipopolysaccharide-induced lung inflammation

BACKGROUND

Respiratory inflammation is the body's response to lung infection, trauma or hypersensitivity and is often accompanied by comorbidities, including gastrointestinal (GI) symptoms. Why respiratory inflammation is accompanied by GI dysfunction remains unclear. Here, we investigate the effect of lipopolysaccharide (LPS)-induced lung inflammation on intestinal barrier integrity, tight-junctions, enteric neurons and inflammatory marker expression.

METHODS

Female C57bl/6 mice (6-8 weeks) were intratracheally administered LPS (5 µg) or sterile saline, and assessed after either 24 or 72 h. Total and differential cell counts in bronchoalveolar lavage fluid (BALF) were used to evaluate lung inflammation. Intestinal barrier integrity was assessed via cross sectional immunohistochemistry of tight junction markers claudin-1, claudin-4 and EpCAM. Changes in the enteric nervous system (ENS) and inflammation in the intestine were quantified immunohistochemically using neuronal markers Hu + and nNOS, glial markers GFAP and S100β and pan leukocyte marker CD45.

RESULTS

Intratracheal LPS significantly increased the number of neutrophils in BALF at 24 and 72 h. These changes were associated with an increase in CD45 + cells in the ileal mucosa at 24 and 72 h, increased goblet cell expression at 24 h, and increased expression of EpCAM at 72 h. LPS had no effect on the expression of GFAP, S100β, nor the number of Hu + neurons or proportion of nNOS neurons in the myenteric plexus.

CONCLUSIONS

Intratracheal LPS administration induces inflammation in the ileum that is associated with enhanced expression of EpCAM, decreased claudin-4 expression and increased goblet cell density, these changes may contribute to systemic inflammation that is known to accompany many inflammatory diseases of the lung.

Commensal microbiota modulates phenotypic characteristics and gene expression in piglet Peyer's patches

The gastrointestinal tract contains a complex microbial community. Peyer's patches (PPs) play an important role in inducing mucosal immune responses in the gastrointestinal tract. However, little is known about the effect of commensal microbiota on the host's PPs. Here, we analyzed the phenotypic-to-transcriptome changes in the intestine PPs of specific pathogen-free (SPF) and germ-free (GF) piglets (fed in an environment with and without commensal microbiota, respectively) to elucidate the role of commensal microbiota in host intestine mucosal immunity. Analyses of anatomical and histological characteristics showed that commensal microbiota deficiency led to PP hypoplasia, especially regarding B and T cells. A total of 12,444 mRNAs were expressed in 12 libraries; 2,156 and 425 differentially expressed (DE) mRNAs were detected in the jejunal PP (JPP) and ileal PP (IPP), respectively (SPF vs. GF). The shared DE mRNAs of the JPP and IPP were mainly involved in basic physiological and metabolic processes, while the specific DE mRNAs were enriched in regulating immune cells in the JPP and microbial responses and cellular immunity in the IPP. Commensal microbiota significantly modulated the expression of genes related to B-cell functions, including activation, proliferation, differentiation, apoptosis, receptor signaling, germinal center formation, and IgA isotype class switching, particularly in the JPP. TLR4 pathway-related genes were induced in response to microbial colonization and in LPS/SCFA-treated B cells. We also detected 69 and 21 DE lncRNAs in the JPP and IPP, respectively, and four one-to-one lncRNA-mRNA pairs were identified. These findings might represent key regulatory axes for host intestine mucosal immunity development during microbial colonization. Overall, the findings of this study revealed that commensal microbiota modulated phenotypic characteristics and gene expression in the piglet intestine PPs and underscored the importance of early microbial colonization for host mucosal immunity development.

The Role of Gut Bacteriome in Asthma, Chronic Obstructive Pulmonary Disease and Obstructive Sleep Apnoea

The human body contains a very complex and dynamic ecosystem of bacteria. The bacteriome interacts with the host bi-directionally, and changes in either factor impact the entire system. It has long been known that chronic airway diseases are associated with disturbances in the lung bacteriome. However, less is known about the role of gut bacteriome in the most common respiratory diseases. Here, we aim to summarise the evidence concerning the role of the intestinal bacteriome in the pathogenesis and disease course of bronchial asthma, chronic obstructive pulmonary disease, and obstructive sleep apnea. Furthermore, we discuss the consequences of an altered gut bacteriome on the most common comorbidities of these lung diseases. Lastly, we also reflect on the therapeutic potential of influencing the gut microbiome to improve disease outcomes.

The Complex Link and Disease Between the Gut Microbiome and the Immune System in Infants

The human gut microbiome is important for human health. The development of stable microbial communities in the gastrointestinal tract is closely related to the early growth and development of host immunity. After the birth of a baby, immune cells and the gut microbiome mature in parallel to adapt to the complex gut environment. The gut microbiome is closely linked to the immune system and influences each other. This interaction is associated with various diseases in infants and young children, such as asthma, food allergies, necrotizing colitis, obesity, and inflammatory bowel disease. Thus, the composition of the infant gut microbiome can predict the risk of disease development and progression. At the same time, the composition of the infant gut microbiome can be regulated in many ways and can be used to prevent and treat disease in infants by modulating the composition of the infant gut microbiome. The most important impacts on infant gut microbiota are maternal, including food delivery and feeding. The differences in the gut microbiota of infants reflect the maternal gut microbiota, which in turn reflects the gut microbiota of a given population, which is clinically significant.

Aspects Towards the Anastomotic Healing in Crohn’s Disease: Clinical Approach and Current Gaps in Research

Anastomotic leakage is a major complication in gastrointestinal and colorectal surgery and its occurrence increases morbidity and mortality. Its incidence is even higher in Crohn’s disease surgeries. Several authors have identified factors involved in the pathophysiology of anastomotic leak in the literature, aiming to reduce its occurrence and, therefore, improve its surgical treatment. Surgical technique is the most discussed topic in studies on guiding the performance of side-to-side stapled anastomosis. Preoperative nutritional therapy also has been shown to reduce the risk of anastomotic leakage. Other factors remain controversial – immunomodulator use and biologic therapy, antibiotics, and gut microbiota – with studies showing a reduction in the risk of complication while other studies show no correlation. Although mesenteric adipose tissue has been related to disease recurrence, there is no evidence in the literature that it is related to a higher risk of anastomotic leakage. Further exploration on this topic is necessary, including prospective research, to support the development of techniques to prevent anastomotic leakage, in this way benefiting the inflammatory bowel disease patients who have to undergo a surgical procedure.

The treatment of Qibai Pingfei Capsule on chronic obstructive pulmonary disease may be mediated by Th17/Treg balance and gut-lung axis microbiota

BACKGROUND

Chronic obstructive pulmonary disease (COPD), a prevalent, progressive respiratory disease, has become the third leading cause of death globally. Increasing evidence suggests that intestinal and pulmonary microbiota dysbiosis is associated with COPD. Researchers have shown that T helper (Th) 17/regulatory T (Treg) imbalance is involved in COPD. Qibai Pingfei Capsule (QBPF) is a traditional Chinese medicine used to treat COPD clinically in China. However, the effects of QBPF intervention on the Th17/Treg balance and microbiota in the gut and lung are still poorly understood.

METHODS

This study divided the rats into three groups (n = 8): control, model, and QBPF group. After establishing the model of COPD for four weeks and administering of QBPF for two weeks, Th17 cells, Treg cells, their associated cytokines, transcription factors, and intestinal and pulmonary microbiota of rats were analyzed. Furthermore, the correlations between intestinal and pulmonary microbiota and between bacterial genera and pulmonary function and immune function were measured.

RESULTS

The results revealed that QBPF could improve pulmonary function and contribute to the new balance of Th17/Treg in COPD rats. Meanwhile, QBPF treatment could regulate the composition of intestinal and pulmonary microbiota and improve community structure in COPD rats, suppressing the relative abundance of Coprococcus_2, Prevotella_9, and Blautia in the gut and Mycoplasma in the lung, but accumulating the relative abundance of Prevotellaceae_UCG_003 in the gut and Rikenellaceae_RC9_gut_group in the lung. Additionally, gut-lung axis was confirmed by the significant correlations between the intestinal and pulmonary microbiota. Functional analysis of microbiota showed amino acid metabolism was altered in COPD rats in the gut and lung. Spearman correlation analysis further enriched the relationship between the microbiota in the gut and lung and pulmonary function and immune function in COPD model rats.

CONCLUSIONS

Our study indicated that the therapeutic effects of QBPF may be achieved by maintaining the immune cell balance and regulating the gut-lung axis microbiota, providing references to explore the potential biomarkers of COPD and the possible mechanism of QBPF to treat COPD.

Functional Significance of Different Milk Constituents in Modulating the Gut Microbiome and Infant Health

Human milk, the gold standard for optimal nourishment, controls the microbial composition of infants by either enhancing or limiting bacterial growth. The milk fat globule membrane has gained interest in gut-related functions and cognitive development. The membrane proteins can directly interact with probiotic bacteria, influencing their survival and adhesion through gastrointestinal transit, whereas membrane phospholipids increase the residence time of probiotic bacteria in the gut. The commensal bacteria in milk act as the initial inoculum in building up the gut colonization of an infant, whereas oligosaccharides promote proliferation of beneficial microorganisms. Interestingly, milk extracellular vesicles are also involved in influencing the microbiota composition but are not well-explored. This review highlights the contribution of different milk components in modulating the infant gut microbiota, particularly the fat globule membrane, and the complex interplay between host- and brain-gut microbiota signaling affecting infant and adult health positively.

The potential application of probiotics for the prevention and treatment of COVID-19

Background

Given the severe infection, poor prognosis, and the low number of available effective drugs, potential prevention and treatment strategies for COVID-19 need to be urgently developed.

Main body

Herein, we present and discuss the possible protective and therapeutic mechanisms of human microbiota and probiotics based on the previous and recent findings. Microbiota and probiotics consist of mixed cultures of living microorganisms that can positively affect human health through their antiviral, antibacterial, anti-inflammatory, and immunomodulatory effect. In the current study, we address the promising advantages of microbiota and probiotics in decreasing the risk of COVID-19.

Conclusions

Thus, we recommend further studies be conducted for assessing and evaluating the capability of these microbes in the battle against COVID-19.

The Role of Gut Microbiota in Gastrointestinal Tract Cancers

Disturbances in gastrointestinal (GI) microbiota could play a significant role in the development of GI cancers, but the underlying mechanisms remain largely unclear. While some bacteria seem to facilitate carcinogenesis, others appear to be protective. So far only one bacterium (Helicobacter pylori) has been classified by the International Agency for Cancer Research as carcinogenic in humans but many other are the subject of intense research. Most studies on the role of microbiota in GI tract oncogenesis focus on pancreatic and colorectal cancers with the following three species: Helicobacter pylori, Escherichia coli, and Porphyromonas gingivalis as likely causative factors. This review summarizes the role of bacteria in GI tract oncogenesis.

Alterations in the Gut Microbial Composition and Diversity of Tibetan Sheep Infected With Echinococcus granulosus

Hydatidosis/cystic echinococcosis (CE) caused by Echinococcus granulosus is a parasitic zoonotic disease worldwide, threatening animal health and production and public health safety. However, it is still unclear that whether E. granulosus infection can result in the alteration of gut microbiota in Tibetan sheep. Therefore, a study was designed to investigate the influences of E. granulosus infection on gut microbiota of Tibetan sheep. A total of 10 ovine small intestinal contents (five from healthy and five from infected) were obtained and subjected to high-throughput sequencing by MiSeq platform. A total of 2,395,641 sequences and 585 operational taxonomic units (OTUs) were identified. Firmicutes and Proteobacteria were the most dominant phyla in all samples. Moreover, the proportions of Armatimonadetes and Firmicutes in the infected Tibetan sheep were significantly decreased, whereas Actinobacteria, Chloroflexi, and Acidobacteria had significantly increased. At the genus level, the Christensenellaceae_R-7_group and Ruminococcaceae_NK4A214_group were the predominant bacterial genera in all the samples. Furthermore, the healthy Tibetan sheep exhibited higher abundances of Intestinimonas, Butyrivibrio, Pseudobutyrivibrio, Ruminococcaceae, Eubacterium_coprostanoligenes_group, Oxobacter, Prevotella_1, Ruminiclostridium_6, Coprococcus_1, Ruminococcus, Lachnospiraceae_UCG-002, Olsenella, and Acetitomaculum, whereas Kocuria, Clostridium_sensu_stricto_1, Slackia, Achromobacter, and Stenotrophomonas levels were lower. In conclusion, our results conveyed an information that E. granulosus infection may cause an increase in pathogenic bacteria and a decrease in beneficial bacteria. Additionally, a significant dynamical change in gut microbiota could be associated with E. granulosus infection.

Comprehensive Bibliometric Analysis of the Kynurenine Pathway in Mood Disorders: Focus on Gut Microbiota Research

Background: Emerging evidence implicates the dysregulated kynurenine pathway (KP), an immune-inflammatory pathway, in the pathophysiology of mood disorders (MD), including depression and bipolar disorder characterized by a low-grade chronic pro-inflammatory state. The metabolites of the KP, an important part of the microbiota-gut-brain axis, serve as immune system modulators linking the gut microbiota (GM) with the host central nervous system.

Aim: This bibliometric analysis aimed to provide a first glimpse into the KP in MD, with a focus on GM research in this field, to guide future research and promote the development of this field.

Methods: Publications relating to the KP in MD between the years 2000 and 2020 were retrieved from the Scopus and Web of Science Core Collection (WoSCC), and analyzed in CiteSpace (5.7 R5W), biblioshiny (using R-Studio), and VOSviewer (1.6.16).

Results: In total, 1,064 and 948 documents were extracted from the Scopus and WoSCC databases, respectively. The publications have shown rapid growth since 2006, partly owing to the largest research hotspot appearing since then, “quinolinic acid.” All the top five most relevant journals were in the neuropsychiatry field, such as Brain Behavior and Immunity. The United States and Innsbruck Medical University were the most influential country and institute, respectively. Journal co-citation analysis showed a strong tendency toward co-citation of research in the psychiatry field. Reference co-citation analysis revealed that the top four most important research focuses were “kynurenine pathway,” “psychoneuroimmunology,” “indoleamine 2,3-dioxygenase,” and “proinflammatory cytokines,” and the most recent focus was “gut-brain axis,” thus indicating the role of the KP in bridging the GM and the host immune system, and together reflecting the field’s research foundations. Overlap analysis between the thematic map of keywords and the keyword burst analysis revealed that the topics “Alzheimer’s disease,” “prefrontal cortex,” and “acid,” were research frontiers.

Conclusion: This comprehensive bibliometric study provides an updated perspective on research associated with the KP in MD, with a focus on the current status of GM research in this field. This perspective may benefit researchers in choosing suitable journals and collaborators, and aid in the further understanding of the field’s hotspots and frontiers, thus facilitating future research.

Potential role of the gut microbiota in neuromyelitis optica spectrum disorder: Implication for intervention

The gut microbiota plays an important role in the occurrence and development of neuroimmunological diseases. Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the central nervous system that is characterized by the peripheral production of the disease-specific serum autoantibody aquaporin-4 (AQP4)-IgG. Recently, accumulating evidence has provided insights into the associations of gut microbiota dysbiosis and intestinal mucosal barrier destruction with NMOSD, but the underlying pathogenesis remains unclear. Thus, a microbiota intervention might be a potential therapeutic strategy for NMOSD by regulating the gut microbiota, repairing the intestinal mucosal barrier, and modulating intestinal immunity and peripheral immunity.

[Gut microbiota and depression : Pathophysiology of depression: hypothalamic-pituitary-adrenal axis and microbiota-gut-brain axis]

Depression is a chronic disease with a complex multifactorial and still not fully clarified etiology. Due to new insights after recent investigations of the microbiota-gut-brain (MGB) axis, a relationship between a disrupted gut microbiota composition and the probability to develop a depression can be assumed. This hypothesis is supported by evidence that there is a strong communication between gut microbiota and the central nervous system (CNS) and that this communication is mediated through the MGB axis. Apparently, this bidirectional axis can be modulated by environmental factors, such as stress, pharmaceuticals (in particular antibiotics) and dietary habits. Moreover, modulation of this axis can also result in mood alterations. As the hypothalamic-pituitary-adrenal (HPA) axis is a key element regulating the MGB axis and is also related to the pathophysiology of depression, it is important to understand the relationship between both biological systems. An English language literature search was conducted using the biomedical database PubMed. We used combined terms, such as "gut microbiota", "depression", "hypothalamic-pituitary-adrenal axis" or "microbiota-gut-brain axis". The current literature supports the idea that the MGB axis has an impact on the risk to develop depression and that stress modulation through the HPA axis plays a key role in this context.

Role of Immune Dysregulation in Increased Mortality Among a Specific Subset of COVID-19 Patients and Immune-Enhancement Strategies for Combatting Through Nutritional Supplements

Background: The COVID-19 pandemic has been causing varying severities of illness. Some are asymptomatic and some develop severe disease leading to mortality across ages. This contrast triggered us explore the causes, with the background that a vaccine for effective immunization or a drug to tackle COVID-19 is not too close to reality. We have discussed strategies to combat COVID-19 through immune enhancement, using simple measures including nutritional supplements. Discussion: A literature search on mortality-related comorbid conditions was performed. For those conditions, we analyzed the pro-inflammatory cytokines, which could cause the draining of the immune reservoir. We also analyzed the immune markers necessary for the defense mechanism/immune surveillance against COVID-19, especially through simple means including immune enhancing nutritional supplement consumption, and we suggest strategies to combat COVID-19. Major comorbid conditions associated with increased mortality include cardiovascular disease (CVD), diabetes, being immunocompromised by cancer, and severe kidney disease with a senile immune system. Consumption of Aureobasidium pullulans strain (AFO-202) beta 1,3-1,6 glucan supported enhanced IL-8, sFAS macrophage activity, and NK cells' cytotoxicity, which are major defense mechanisms against viral infection. Conclusion: People with co-morbid conditions who are more prone to COVID-19-related deaths due to immune dysregulation are likely to benefit from consuming nutritional supplements that enhance the immune system. We recommend clinical studies to validate AFO-202 beta glucan in COVID-19 patients to prove its efficacy in overcoming a hyper-inflammation status, thus reducing the mortality, until a definite vaccine is made available.

Human microbiome: an academic update on human body site specific surveillance and its possible role

Human body is inhabited by vast number of microorganisms which form a complex ecological community and influence the human physiology, in the aspect of both health and diseases. These microbes show a relationship with the human immune system based on coevolution and, therefore, have a tremendous potential to contribute to the metabolic function, protection against the pathogen and in providing nutrients and energy. However, of these microbes, many carry out some functions that play a crucial role in the host physiology and may even cause diseases. The introduction of new molecular technologies such as transcriptomics, metagenomics and metabolomics has contributed to the upliftment on the findings of the microbiome linked to the humans in the recent past. These rapidly developing technologies are boosting our capacity to understand about the human body-associated microbiome and its association with the human health. The highlights of this review are inclusion of how to derive microbiome data and the interaction between human and associated microbiome to provide an insight on the role played by the microbiome in biological processes of the human body as well as the development of major human diseases.

Impact of Prebiotics on Enteric Diseases and Oxidative Stress

In animals, the gastrointestinal microbiota are reported to play a major role in digestion, nutrient absorption and the release of energy through metabolism of food. Therefore, microbiota may be a factor for association between diet and enteric diseases and oxidative stress. The gut microbial composition and concentration are affected by diet throughout the life of an animal, and respond rapidly and efficiently to dietary alterations, in particular to the use of prebiotics. Prebiotics, which play an important role in mammalian nutrition, are defined as dietary ingredients that lead to specific changes in both the composition and activity of the gastrointestinal microbiota through suppressing the proliferation of pathogens and by modifying the growth of beneficial microorganisms in the host intestine. A review of the evidence suggests possible beneficial effects of prebiotics on host intestinal health, including immune stimulation, gut barrier enhancement and the alteration of the gastrointestinal microbiota, and these effects appear to be dependent on alteration of the bacterial composition and short-chain fatty acid (SCFA) production. The production of SCFAs depends on the microbes available in the gut and the type of prebiotics available. The SCFAs most abundantly generated by gastrointestinal microbiota are acetate, butyrate and propionate, which are reported to have physiological effects on the health of the host. Nowadays, prebiotics are widely used in a range of food products to improve the intestinal microbiome and stimulate significant changes to the immune system. Thus, a diet with prebiotic supplements may help prevent enteric disease and oxidative stress by promoting a microbiome associated with better growth performance. This paper provides an overview of the hypothesis that a combination of ingestible prebiotics, chitosan, fructooligosaccharides and inulin will help relieve the dysbiosis of the gut and the oxidative stress of the host.

The Gut-Lung Axis in Health and Respiratory Diseases: A Place for Inter-Organ and Inter-Kingdom Crosstalks

The gut and lungs are anatomically distinct, but potential anatomic communications and complex pathways involving their respective microbiota have reinforced the existence of a gut-lung axis (GLA). Compared to the better-studied gut microbiota, the lung microbiota, only considered in recent years, represents a more discreet part of the whole microbiota associated to human hosts. While the vast majority of studies focused on the bacterial component of the microbiota in healthy and pathological conditions, recent works have highlighted the contribution of fungal and viral kingdoms at both digestive and respiratory levels. Moreover, growing evidence indicates the key role of inter-kingdom crosstalks in maintaining host homeostasis and in disease evolution. In fact, the recently emerged GLA concept involves host-microbe as well as microbe-microbe interactions, based both on localized and long-reaching effects. GLA can shape immune responses and interfere with the course of respiratory diseases. In this review, we aim to analyze how the lung and gut microbiota influence each other and may impact on respiratory diseases. Due to the limited knowledge on the human virobiota, we focused on gut and lung bacteriobiota and mycobiota, with a specific attention on inter-kingdom microbial crosstalks which are able to shape local or long-reached host responses within the GLA.

Differences in Gut Microbial and Serum Biochemical Indices Between Sows With Different Productive Capacities During Perinatal Period

Maternal gut microflora changes dramatically during perinatal period and plays a vital role in animal health and reproductive performance. However, little is known about the microbial differences between sows with different productive capacities during perinatal period. Hence, this study explored fecal microbial diversity, composition, metabolic functions, and phenotypes differences between high productive capacity (HPC, litter size ≥ 15) and low productive capacity (LPC, litter size ≤ 7) sows during late pregnancy (LP, the third day before due date) and early stage after parturition (EAP, the third day after parturition) as well as serum biochemical indices differences after parturition. Results showed that HPC sows had lower microbial richness at LP stage and higher microbial diversity at EAP stage than LPC sows. Several genera belonging to the Prevotellaceae family exhibited higher abundance, while some genera belonging to the Ruminococcaceae family exhibited lower abundance in HPC sows compared to LPC sows at LP stage. Moreover, the relative abundance of Eubacterium_coprostanoligenes_group and Ruminococcaceae_UCG-014 in HPC sows was significantly higher than that in LPC sows at EAP stage. The predicted metabolic functions related to Lipopolysaccharide biosynthesis were significantly higher in HPC sows at LP stage. Further, HPC sows had significantly higher blood urea nitrogen (BUN) and high-density lipoprotein cholesterol (HDL-C) levels after parturition, and there were strong correlations between BUN level and the relative abundance of genera belonging to the Ruminococcaceae families. These results indicated that the HPC sows may experience greater inflammation than LPC sows at LP stage. Inflammation environment might impact health but promote parturition. The microbial differences at EAP stage might be beneficial to hemostasis and anti-inflammation, which might contribute to postpartum recovery in HPC sow.

Bibliometric and Visual Analysis of Research on the Links Between the Gut Microbiota and Depression From 1999 to 2019

Background: There is a crucial link between the gut microbiota and the host central nervous system, and the communication between them occurs via a bidirectional pathway termed the "microbiota-gut-brain axis." The gut microbiome in the modern environment has markedly changed in response to environmental factors. These changes may affect a broad range of host psychiatric disorders, such as depression, by interacting with the host through metabolic, immune, neural, and endocrine pathways. Nevertheless, the general aspects of the links between the gut microbiota and depression have not been systematically investigated through bibliometric analysis. Aim: This study aimed to analyze the current status and developing trends in gut microbiota research in the depression field through bibliometric and visual analysis. Methods: A total of 1,962 publications published between 1999 and 2019 were retrieved from the Web of Science Core Collection. CiteSpace (5.6 R5) was used to perform collaboration network analysis, co-citation analysis, co-occurrence analysis, and citation burst detection. Results: The number of publications has been rapidly growing since 2010. The collaboration network analysis revealed that the USA, University College Cork, and John F. Cryan were the most influential country, institute, and scholar, respectively. The most productive and co-cited journals were Brain Behavior and Immunity and Proceedings of the National Academy of Sciences of the United States of America, respectively. The co-citation analysis of references revealed that the most recent research focus was in the largest theme cluster, "cytokines," thus reflecting the important research foundation in this field. The co-occurrence analysis of keywords revealed that "fecal microbiota" and "microbiome" have become the top two research hotspots since 2013. The citation burst detection for keywords identified several keywords, including "Parkinson's disease," "microbiota-gut-brain axis," "microbiome," "dysbiosis," "bipolar disorder," "impact," "C reactive protein," and "immune system," as new research frontiers, which have currently ongoing bursts. Conclusions: These results provide an instructive perspective on the current research and future directions in the study of the links between the gut microbiota and depression, which may help researchers choose suitable cooperators or journals, and promote their research illustrating the underlying molecular mechanisms of depression, including its etiology, prevention, and treatment.

Studies on patients establish Crohn's disease as a manifestation of impaired innate immunity

The fruitless search for the cause of Crohn's disease has been conducted for more than a century. Various theories, including autoimmunity, mycobacterial infection and aberrant response to food and other ingested materials, have been abandoned for lack of robust proof. This review will provide the evidence, obtained from patients with this condition, that the common predisposition to Crohn's is a failure of the acute inflammatory response to tissue damage. This acute inflammation normally attracts large numbers of neutrophil leucocytes which engulf and clear bacteria and autologous debris from the inflamed site. The underlying predisposition in Crohn's disease is unmasked by damage to the bowel mucosa, predominantly through infection, which allows faecal bowel contents access to the vulnerable tissues within. Consequent upon failure of the clearance of these infectious and antigenic intestinal contents, it becomes contained, leading to a chronic granulomatous inflammation, producing cytokine release, local tissue damage and systemic symptoms. Multiple molecular pathologies extending across the whole spectrum of the acute inflammatory and innate immune response lead to the common predisposition in which defective monocyte and macrophage function plays a central role. Family linkage and exome sequencing together with GWAS have identified some of the molecules involved, including receptors, molecules involved in vesicle trafficking, and effector cells. Current therapy is immunosuppressant, which controls the symptoms but accentuates the underlying problem, which can only logically be tackled by correcting the primary lesion/s by gene therapy or genome editing, or through the development of drugs that stimulate innate immunity.

Novel Microbial-Based Immunotherapy Approach for Crohn's Disease

Background: Current Crohn's disease (CD) therapies focus on suppressing immune function and come with consequent risk, such as infection and cancer. Notwithstanding, most CD patients still experience disease progression. There is a need for new CD treatment strategies that offer better health outcomes for patients.

Aims: To assess safety, efficacy, and tolerability of a novel microbial-derived immunotherapy, QBECO, that aims to restore rather than suppress immune function in CD.

Methods: A randomized, double-blind, placebo-controlled trial was conducted in 68 patients with moderate-to-severe CD. Primary endpoints: safety and Week 8 clinical improvement. Secondary endpoints: Week 8 clinical response and remission. Week 8 responders continued blinded treatment through Week 16; non-responders received open-label QBECO from Weeks 9–16. Exploratory analyses included immune biomarker and genotype assessments.

Results: QBECO was well-tolerated. Mean reduction in Crohn's Disease Activity Index (CDAI) score was −68 for QBECO vs. −31 for placebo at Week 8. Improvement with QBECO continued through Week 16 (-130 CDAI reduction). Week 8 QBECO clinical response, improvement and remission rates were 41.2%, 32.4%, 29.4% vs. 26.5%, 23.5%, 23.5% for placebo. TNFα inhibitor-naïve subjects achieved higher response rates at Week 8 with QBECO (64%) vs. placebo (26%). Specific immune biomarkers were identified that linked to QBECO response.

Conclusion: This proof-of-concept study supports further investigation for the use of QBECO as a novel immunotherapy approach for CD. Biomarker analyses suggests it may be feasible to personalize CD treatment with QBECO. Larger trials are now needed to confirm clinical improvement and the unique biological findings.

Clinical Trial Number: NCT01809275 (https://clinicaltrials.gov/ct2/show/NCT01809275)

Current evidence on the relation between gut microbiota and intestinal anastomotic leak in colorectal surgery

BACKGROUND

Anastomotic leak (AL) is a major complication in colorectal surgery. It worsens morbidity, mortality and oncological outcomes in colorectal cancer. Some evidence suggests a potential effect of the intestinal microbiome on wound healing. This review aims to provide a comprehensive review on historical and current evidence regarding the relation between the gastrointestinal microbiota and AL in colorectal surgery, and the potential microbiota-modifying effect of some perioperative commonly used measures.

DATA SOURCES

A comprehensive search was conducted in Pubmed, Medline and Embase for historical and current clinical and animal studies addressing perioperative intestinal microbiota evaluation, intestinal healing and AL.

CONCLUSIONS

Evidence on microbes' role in AL is mainly derived from animal experiments. The microbiota's composition and implications are poorly understood in surgical patients. Elaborate microbiota sequencing is required in colorectal surgery to identify potentially beneficial microbial profiles that could lead to specific perioperative microbiome-altering measures and improve surgical and oncological outcomes.

[Gut human microbiota and multiple sclerosis]

Recently the relationship between gut microbiota changes and the development of immune-mediated diseases of the central nervous system (CNS) has been reported. This review presents literature data on the effect of gut microbiota on the function of the immune and nervous systems. The authors discuss possible mechanisms of the relationship between gut microbiota changes and CNS diseases on the model of multiple sclerosis (MS).

Autoimmune Diseases and Psychotic Disorders

The notion of immunological pathways playing a role in the etiology of a subset of psychotic disorders has received increased interest in the last decades. One of the findings that has spiked interest herein, is an apparent link between autoimmune diseases and psychotic disorders. This is supported by genetic findings associating immune-related genetic markers with schizophrenia and clinical studies finding increased levels of inflammatory markers in patients with psychosis. Several large-scale epidemiologic studies have found positive associations between autoimmune diseases and psychosis. Particularly, autoimmune diseases as multiple sclerosis and lupus are known to have higher frequencies of neuropsychiatric symptoms, including psychosis, compared to healthy controls. Cross sectional studies have found higher prevalence of psychiatric diagnoses among those with autoimmune diseases, and longitudinal studies have shown bidirectional associations between several autoimmune diseases and increased risks associated with schizophrenia. Moreover, a family history of autoimmune diseases has been shown to be associated with an increased risk of psychotic disorders and vice versa. In this review we will summarize the epidemiologic evidence on associations between autoimmune diseases and psychosis. Possible mechanisms accountable for the association will be discussed, amongst others the probable role of shared genetic risk factors, the impact of infections on both autoimmunity and the development of psychotic disorders, and the potential role of the microbiome. We discuss the findings on and influence of autoantibodies and dysregulation of T- and B-cells in both disease categories, and why further research hereon is needed. In addition to the potential importance of autoimmunity in etiological mechanisms of psychotic disorders, the association also brings important attention to somatic comorbidity in patients with psychotic disorders.

Intestinal in vitro and ex vivo Models to Study Host-Microbiome Interactions and Acute Stressors

The gut microbiome is extremely important for maintaining homeostasis with host intestinal epithelial, neuronal, and immune cells and this host-microbe interaction is critical during times of stress or disease. Environmental, nutritional, and cognitive stress are just a few factors known to influence the gut microbiota and are thought to induce microbial dysbiosis. Research on this bidirectional relationship as it pertains to health and disease is extensive and rapidly expanding in both in vivo and in vitro/ex vivo models. However, far less work has been devoted to studying effects of host-microbe interactions on acute stressors and performance, the underlying mechanisms, and the modulatory effects of different stressors on both the host and the microbiome. Additionally, the use of in vitro/ex vivo models to study the gut microbiome and human performance has not been researched extensively nor reviewed. Therefore, this review aims to examine current evidence concerning the current status of in vitro and ex vivo host models, the impact of acute stressors on gut physiology/microbiota as well as potential impacts on human performance and how we can parlay this information for DoD relevance as well as the broader scientific community. Models reviewed include widely utilized intestinal cell models from human and animal models that have been applied in the past for stress or microbiology research as well as ex vivo organ/tissue culture models and new innovative models including organ-on-a-chip and co-culture models.

The role of neutrophils in the pathogenesis of Crohn's disease

Crohn's disease (CD) is caused by a trigger, almost certainly enteric infection by one of a multitude of organisms that allows faeces access to the tissues, at which stage the response of individuals predisposed to CD is abnormal. In CD the failure of acute inflammation results in the failure to recruit neutrophils to the inflammatory site, as a consequence of which the clearance of bacteria from the tissues is defective. The retained faecal products result in the characteristic chronic granulomatous inflammation and adaptive immune response. Impaired of digestion of bacteria and fungi by CGD neutrophils can result in a similar pathological and clinical picture. The neutrophils in CD are normal and their inadequate accumulation at sites of inflammation generally results from diminished secretion of proinflammatory cytokines by macrophages consequent upon disordered vesicle trafficking.

New Insights on the Pathogenesis of Takayasu Arteritis: Revisiting the Microbial Theory

Takayasu arteritis (TAK) is a chronic vasculitis that mainly affects the aorta, its major branches, and the pulmonary arteries. Since the description of the first case by Mikito Takayasu in 1908, several aspects of this rare disease, including the epidemiology, diagnosis, and the appropriate clinical assessment, have been substantially defined. Nevertheless, while it is well-known that TAK is associated with a profound inflammatory process, possibly rooted to an autoimmune disorder, its precise etiology has remained largely unknown. Efforts to identify the antigen(s) that trigger autoimmunity in this disease have been unsuccessful, however, it is likely that viruses or bacteria, by a molecular mimicry mechanism, initiate or propagate the auto-immune process in this disease. In this article, we summarize recent advances in the understanding of TAK, with emphasis on new insights related to the pathogenesis of this entity that may contribute to the design of novel therapeutic approaches.

Psoriasis and infection. A clinical practice narrative

The Australasian Psoriasis Collaboration has developed a clinical practice narrative with respect to the relationship between psoriasis, its treatment and infection. The cutaneous microbiome of patients with psoriasis is different to those without psoriasis, although the significance of this is unclear. Whilst a wide range of microorganisms has been associated with psoriasis (including β-haemolytic streptococci, Staphylococcus aureus, Porphyromonas gingivalis, Candida albicans, Chlamydia psittaci, human immunodeficiency virus and hepatitis C virus), there is limited evidence that antimicrobial therapy is of direct benefit in preventing flares of psoriasis. Psoriasis is independently associated with an increased risk of serious infection, but the absolute risk is low. The risk of serious infections is further increased with immune-modulatory treatments. The decision whether to, and when to, stop or resume immune-modulatory treatment after a serious infection has occurred depends on risk assessment for that patient, taking into account the infection being treated, the risk of recurrent infection, any interventions that can modify the risk and the need for psoriasis control. Live vaccines (e.g. MMR, varicella, zoster and yellow fever) are generally contraindicated in patients with psoriasis on immune-modulatory agents, but this depends on the degree of immune suppression and individual risk factors. Wound healing in psoriasis is normal. Treatment with infliximab, adalimumab, etanercept, methotrexate and ciclosporin can safely be continued through low-risk surgical procedures. For moderate- and high-risk surgeries, a case-by-case approach should be taken based on the patient's individual risk factors and comorbidities.

Simultaneous Amelioratation of Colitis and Liver Injury in Mice by Bifidobacterium longum LC67 and Lactobacillus plantarum LC27

Disturbances in the gut microbiota composition are associated with chronic inflammatory diseases of the intestine and the liver. In a preliminary study, Lactobacillus plantarum LC27 and Bifidobacterium longum LC67 could inhibit Escherichia coli growth and lipopolysaccharide-induced NF-κB activation linked to gut inflammation. Here, we investigated their effects on 2,4,6-trinitrobenzesulfonic acid (TNBS)-induced colitis and liver damage in mice. First, oral administration of LC27 or LC67 (1 × 10⁹ CFU/mouse) inhibited TNBS-induced colon shortening [F(5,30) = 100.66, P < 0.05] and myeloperoxidase activity [F(5,30) = 56.48, P < 0.05]. These probiotics restored TNBS-induced disturbance of gut microbiota, leading to the suppression of Proteobacteria to Bacteroidetes ratio and fecal and blood lipopolysaccharide levels. Second, LC27 and LC67 inhibited TNBS-induced NF-κB activation, reversed TNBS-suppressed tight junction protein expression, and restored Th17/Treg balance. Also, treatment with LC27 or LC67 significantly decreased TNBS-induced alanine transaminase [ALT, F(5,30) = 3.50, P < 0.05] and aspartate transaminase [AST, F(5,30) = 12.81, P < 0.05] levels in the blood, as well as t-butylhydroperoxide-induced ALT and AST levels. Finally, the mixture of LC27 and LC67 (0.5 × 10⁹ CFU/mouse, respectively) synergistically attenuated TNBS- or t-butylhydroperoxide-induced colitis and liver damage. The capability of LC27 and LC67 to reverse TNBS-mediated microbiota shift and damage signals suggests that these probiotics may synergistically attenuate colitis and liver injury by alleviating gut microbiota imbalance.

Does Modification of the Large Intestinal Microbiome Contribute to the Anti-Inflammatory Activity of Fermentable Fiber?

Fiber is an inadequately understood and insufficiently consumed nutrient. This review examines the possible causal relation between fiber-induced microbiome changes and the anti-inflammatory activity of fiber. To demonstrate the dominant role of fermentable plant fiber in shaping the intestinal microbiome, animal and human fiber-feeding studies are reviewed. Using culture-, PCR-, and sequencing-based microbial analyses, a higher prevalence of Bifidobacterium and Lactobacillus genera was observed from the feeding of different types of fermentable fiber. This finding was reported in studies performed on several host species including human. Health conditions and medications that are linked to intestinal microbial alterations likely also change the nutrient environment of the large intestine. The unique gene clusters of Bifidobacterium and Lactobacillus that enable the catabolism of plant glycans and the ability of Bifidobacterium and Lactobacillus to reduce the colonization of proteobacteria probably contribute to their prevalence in a fiber-rich intestinal environment. The fiber-induced microbiome changes could contribute to the anti-inflammatory activity of fiber. Although most studies did not measure fecal microbial density or total daily fecal microbial output (colon microbial load), limited evidence suggests that the increase in intestinal commensal microbial load plays an important role in the anti-inflammatory activity of fiber. Various probiotic supplements, including Bifidobacterium and Lactobacillus, showed anti-inflammatory activity only in the presence of fiber, which promoted microbial growth as indicated by increasing plasma short-chain fatty acids. Probiotics alone or pure fiber administered under sterile conditions showed no anti-inflammatory activity. The potential mechanisms that could mediate the anti-inflammatory effect of common microbial metabolites are reviewed, but more in vivo trials are needed. Future studies including simultaneous microbial composition and load measurements are also important.

Airway Microbiota and the Implications of Dysbiosis in Asthma

The mucosal surfaces of the human body are typically colonized by polymicrobial communities seeded in infancy and are continuously shaped by environmental exposures. These communities interact with the mucosal immune system to maintain homeostasis in health, but perturbations in their composition and function are associated with lower airway diseases, including asthma, a developmental and heterogeneous chronic disease with various degrees and types of airway inflammation. This review will summarize recent studies examining airway microbiota dysbioses associated with asthma and their relationship with the pathophysiology of this disease.

Organoids: Modeling Development and the Stem Cell Niche in a Dish

Organoids are three-dimensional in-vitro-grown cell clusters with near-native microanatomy that arise from self-organizing mammalian pluripotent or adult stem cells. Although monolayer stem cell cultures were established more than 40 years ago, organoid technology has recently emerged as an essential tool for both fundamental and biomedical research. For developmental biologists, organoids provide powerful means for ex vivo modeling of tissue morphogenesis and organogenesis. Here we discuss how organoid cultures of the intestine and other tissues have been established and how they are utilized as an in vitro model system for stem cell research and developmental biology.

Bifidobacterium adolescentis IM38 ameliorates high-fat diet-induced colitis in mice by inhibiting NF-κB activation and lipopolysaccharide production by gut microbiota

Gut microbiota play essential roles in the regulation of human metabolism via symbiotic interactions with the host. Prolonged consumption of high-fat diet (HFD) elevates the Firmicutes to Bacteroidetes ratio and lipopolysaccharide (LPS) production by gut microbiota, thereby increasing the probability of developing metabolic and immune disorders such as obesity and colitis. The use of probiotics with anti-inflammatory properties has been suggested to counteract this effect. Here, we tested whether Bifidobacterium adolescentis IM38, which inhibited nuclear factor-kappa B (NF-κB) activation in Caco-2 cells and peritoneal macrophages and inhibited Escherichia coli LPS production, exerted an anticolitic effect in mice with HFD-induced obesity. Oral administration of IM38 (2×10⁹CFU/mouse per day) for 6 weeks in mice with HFD-induced obesity inhibited whole-body and epididymal fat weight gain. IM38 also increased HFD-suppressed expression of interleukin (IL)-10 and tight junction proteins but significantly downregulated HFD-induced NF-κB activation and tumor necrosis factor expression in the colon. IM38 inhibited differentiation into helper T17 cells and reduced IL-17 levels in the colon of mice with HFD-induced obesity but increased HFD-suppressed differentiation into regulatory T cells and IL-10 levels. Furthermore, treatment with IM38 lowered the HFD-induced LPS levels in blood and colonic fluid, as well as the Proteobacteria to Bacteroidetes ratio in gut microbiota. Therefore, we suggest that IM38 can inhibit HFD-induced LPS production in gut microbiota through the regulation of Proteobacteria to Bacteroidetes ratio and NF-κB activation in the colon, which ultimately attenuates colitis. Thus, IM38 may be a suitable ingredient of functional foods designed for treating or preventing colitis.

Critical role of environmental factors in the pathogenesis of psoriasis

Psoriasis is a common cutaneous disease with multifactorial etiology including genetic and non-genetic factors, such as drugs, smoking, drinking, diet, infection and mental stress. Now, the role of the interaction between environmental factors and genetics are considered to be a main factor in the pathogenesis of psoriasis. However, it is a challenge to explore the mechanisms how the environmental factors break the body balance to affect the onset and development of psoriasis. In this article, we review the pathogenesis of psoriasis and summarize numerous clinical data to reveal the association between environmental factors and psoriasis. In addition, we focus on the mechanisms of environmental risk factors impact on psoriasis and provide a series of potential treatments against environmental risk factors.

Microbiome, growth retardation and metabolism: are they related?

CONTEXT

Despite an improvement in food security and the delivery of nutritional supplements to children living in impoverished parts of the world, poor growth is still highly prevalent. Given that the microbiome is related to both nutrient absorption, as well as overweight/obesity, it may play a central role in limiting or modifying normal growth processes while contributing to chronic disease risks.

OBJECTIVE

The objective of this paper is to describe normal growth processes, the role of the microbiome in supporting or disrupting normal growth processes, and its potential impact on long-term health.

METHODS

A literature search of relevant human and laboratory research on growth, microbiome and the relationship between poor growth and chronic diseases was conducted. This review focuses on potential mechanisms that implicate the microbiome as a mediator of poor growth and later metabolic outcomes. In this relationship, attention was given to the potential for gastrointestinal infections to disrupt the microbiome.

RESULTS

Based on the studies reviewed, it is clear that exposure to infections disturbs both intestinal functioning as well as normal growth and changes in the microbiome may influence micronutrient availability and metabolic processes.

CONCLUSIONS

The microbiome may play a significant role in limiting human growth, but little is known about changes in the microbiome during periods of undernutrition. Thus, it is of great scientific and public health importance to improve the understanding of how the microbiome changes during nutrient deprivation. To best address the issue of the double burden and poor growth in low-income countries, research is warranted to advance the knowledge of the long-term role of the microbiome in the health of children exposed to undernutrition.

"I Am I and My Bacterial Circumstances": Linking Gut Microbiome, Neurodevelopment, and Depression

Recently, there has been renewed interest in the role played by microbiome in both human health and human disease. A correct equilibrium between the human host and their microorganisms is important for an appropriate physiological function. Extensive research has shown that microbes that inhabit the gastrointestinal tract-or gut microbiota-are involved not only in both nutritive and digestive activities but also in immunological processes. Moreover, the gut microbiome influences both central nervous system and energy homeostasis. An altered gut microbiome has been associated with the pathophysiology of different diseases, including neuropsychiatric disorders. Apparently, both environmental-diet, exposition to antibiotics, and infections-and host-genetic factors have a strong influence on gut microbiome, modulating the risk for neuropsychiatric illness. Also, early life disruption of the microbiome-gut-brain (MGB) axis has been associated with an increased risk of developing depression later in life, suggesting a link between gut microbiome, neurodevelopment, and depression. This review aims to contribute to this growing area of research by exploring the role played by the gut microbiome in neurodevelopment and in the etiology of the depressive syndrome, including nutritional, immunological, and energy homeostasis approaches.

Eicosanoid receptors: Targets for the treatment of disrupted intestinal epithelial homeostasis

The importance of cyclooxygenase and lipoxygenase pathways and the consequent eicosanoid synthesis in the physiology and pathophysiology of the intestinal epithelium is currently being established. Each eicosanoid (prostanoid, leukotriene, hydroxyeicosatetraenoic acid) preferentially recognizes one or more receptors coupled to one or more signal-transduction processes. This overview focuses on the role of eicosanoid receptors in the maintenance of intestinal epithelium physiology through the control of proliferation/differentiation/apoptosis processes. Furthermore, it is reported that the role of these receptors on the regulation of the barrier function of the intestinal epithelium have arisen through the regulation of absorption/secretion processes, tight-junction state and the control of the intestinal immune response. Also, this review considers the implication of AA cascade in the disruption of epithelial homeostasis during inflammatory bowel diseases and colorectal cancer as well as the therapeutic values and potential of the eicosanoid receptors as novel targets for the treatments of the pathologies above mentioned.

B cells and their role in the teleost gut

Mucosal surfaces are the main route of entry for pathogens in all living organisms. In the case of teleost fish, mucosal surfaces cover the vast majority of the animal. As these surfaces are in constant contact with the environment, fish are perpetually exposed to a vast number of pathogens. Despite the potential prevalence and variety of pathogens, mucosal surfaces are primarily populated by commensal non-pathogenic bacteria. Indeed, a fine balance between these two populations of microorganisms is crucial for animal survival. This equilibrium, controlled by the mucosal immune system, maintains homeostasis at mucosal tissues. Teleost fish possess a diffuse mucosa-associated immune system in the intestine, with B cells being one of the main responders. Immunoglobulins produced by these lymphocytes are a critical line of defense against pathogens and also prevent the entrance of commensal bacteria into the epithelium. In this review we will summarize recent literature regarding the role of B-lymphocytes and immunoglobulins in gut immunity in teleost fish, with specific focus on immunoglobulin isotypes and the microorganisms, pathogenic and non-pathogenic that interact with the immune system.

Making sense of the cause of Crohn's - a new look at an old disease

The cause of Crohn’s disease (CD) has posed a conundrum for at least a century. A large body of work coupled with recent technological advances in genome research have at last started to provide some of the answers. Initially this review seeks to explain and to differentiate between bowel inflammation in the primary immunodeficiencies that generally lead to very early onset diffuse bowel inflammation in humans and in animal models, and the real syndrome of CD. In the latter, a trigger, almost certainly enteric infection by one of a multitude of organisms, allows the faeces access to the tissues, at which stage the response of individuals predisposed to CD is abnormal. Direct investigation of patients’ inflammatory response together with genome-wide association studies (GWAS) and DNA sequencing indicate that in CD the failure of acute inflammation and the clearance of bacteria from the tissues, and from within cells, is defective. The retained faecal products result in the characteristic chronic granulomatous inflammation and adaptive immune response. In this review I will examine the contemporary evidence that has led to this understanding, and look for explanations for the recent dramatic increase in the incidence of this disease.

Making sense of the cause of Crohn's - a new look at an old disease

The cause of Crohn's disease (CD) has posed a conundrum for at least a century. A large body of work coupled with recent technological advances in genome research have at last started to provide some of the answers. Initially this review seeks to explain and to differentiate between bowel inflammation in the primary immunodeficiencies that generally lead to very early onset diffuse bowel inflammation in humans and in animal models, and the real syndrome of CD. In the latter, a trigger, almost certainly enteric infection by one of a multitude of organisms, allows the faeces access to the tissues, at which stage the response of individuals predisposed to CD is abnormal. Direct investigation of patients' inflammatory response together with genome-wide association studies (GWAS) and DNA sequencing indicate that in CD the failure of acute inflammation and the clearance of bacteria from the tissues, and from within cells, is defective. The retained faecal products result in the characteristic chronic granulomatous inflammation and adaptive immune response. In this review I will examine the contemporary evidence that has led to this understanding, and look for explanations for the recent dramatic increase in the incidence of this disease.

Progress in Our Understanding of the Gut Microbiome: Implications for the Clinician

The investigation of the role of the microbial communities of our gastrointestinal tract (microbiota) has accelerated dramatically in recent years thanks to rapid developments in the technologies that allow us to fully enumerate and evaluate the full complement of bacterial species and strains that normally inhabit the gut. Laboratory studies in a range of inventive animal models continue to provide insights into the role of the microbiota in health and to generate plausible hypotheses relating to its potential involvement in the pathogenesis of human disease. Studies of the composition of human gut microbiota continue to accumulate but their interpretation needs to be tempered by an appreciation of the limitations of single-point-in-time studies of fecal samples from small study populations. Nevertheless, clinically important examples of a central role for microbiota-host interactions in disease pathogenesis have emerged and many more have been postulated but await confirmation in appropriately powered and conducted studies.