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1.
From the Role of Microbiota in Gut-Lung Axis to SARS-CoV-2 Pathogenesis.
Ahmadi Badi, S, Tarashi, S, Fateh, A, Rohani, P, Masotti, A, Siadat, SD
Mediators of inflammation. 2021;:6611222
Abstract
Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is responsible for the outbreak of a new viral respiratory infection. It has been demonstrated that the microbiota has a crucial role in establishing immune responses against respiratory infections, which are controlled by a bidirectional cross-talk, known as the "gut-lung axis." The effects of microbiota on antiviral immune responses, including dendritic cell (DC) function and lymphocyte homing in the gut-lung axis, have been reported in the recent literature. Additionally, the gut microbiota composition affects (and is affected by) the expression of angiotensin-converting enzyme-2 (ACE2), which is the main receptor for SARS-CoV-2 and contributes to regulate inflammation. Several studies demonstrated an altered microbiota composition in patients infected with SARS-CoV-2, compared to healthy individuals. Furthermore, it has been shown that vaccine efficacy against viral respiratory infection is influenced by probiotics pretreatment. Therefore, the importance of the gut microbiota composition in the lung immune system and ACE2 expression could be valuable to provide optimal therapeutic approaches for SARS-CoV-2 and to preserve the symbiotic relationship of the microbiota with the host.
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2.
Early life microbial exposures and allergy risks: opportunities for prevention.
Renz, H, Skevaki, C
Nature reviews. Immunology. 2021;(3):177-191
Abstract
Allergies, including asthma, food allergy and atopic dermatitis, are increasing in prevalence, particularly in westernized countries. Although a detailed mechanistic explanation for this increase is lacking, recent evidence indicates that, in addition to genetic predisposition, lifestyle changes owing to modernization have an important role. Such changes include increased rates of birth by caesarean delivery, increased early use of antibiotics, a westernized diet and the associated development of obesity, and changes in indoor and outdoor lifestyle and activity patterns. Most of these factors directly and indirectly impact the formation of a diverse microbiota, which includes bacterial, viral and fungal components; the microbiota has a leading role in shaping (early) immune responses. This default programme is markedly disturbed under the influence of environmental and lifestyle risk factors. Here, we review the most important allergy risk factors associated with changes in our exposure to the microbial world and the application of this knowledge to allergy prevention strategies.
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3.
Novel mechanisms of microbial crosstalk with skin innate immunity.
Chinnappan, M, Harris-Tryon, TA
Experimental dermatology. 2021;(10):1484-1495
Abstract
Skin is an organ with a dynamic ecosystem that harbours pathogenic and commensal microbes, which constantly communicate amongst each other and with the host immune system. Evolutionarily, skin and its microbiota have evolved to remain in homeostasis. However, frequently this homeostatic relationship is disturbed by a variety of factors such as environmental stress, diet, genetic mutations, and the microbiome itself. Commensal microbes also play a major role in the maintenance of microbial homeostasis. In addition to their ability to limit pathogens, many skin commensals such as Staphylococcus epidermidis and Cutibacterium acnes have recently been implicated in disease pathogenesis either by directly modulating the host immune components or by supporting the expansion of other pathogenic microbes. Likewise, opportunistic skin pathogens such as Staphylococcus aureus and Staphylococcus lugdunensis are able to breach the skin and cause disease. Though much has been established about the microbiota's function in skin immunity, we are in a time where newer mechanistic insights rapidly redefine our understanding of the host/microbial interface in the skin. In this review, we provide a concise summary of recent advances in our understanding of the interplay between host defense strategies and the skin microbiota.
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4.
Targeting the microbiome-gut-brain axis for improving cognition in schizophrenia and major mood disorders: A narrative review.
Bioque, M, González-RodrĂguez, A, Garcia-Rizo, C, Cobo, J, Monreal, JA, Usall, J, Soria, V, , , Labad, J
Progress in neuro-psychopharmacology & biological psychiatry. 2021;:110130
Abstract
Cognitive impairment has been consistently found to be a core feature of serious mental illnesses such as schizophrenia and major mood disorders (major depression and bipolar disorder). In recent years, a great effort has been made in elucidating the biological causes of cognitive deficits and the search for new biomarkers of cognition. Microbiome and gut-brain axis (MGB) hormones have been postulated to be potential biomarkers of cognition in serious mental illnesses. The main aim of this review was to synthesize current evidence on the association of microbiome and gut-brain hormones on cognitive processes in schizophrenia and major mood disorders and the association of MGB hormones with stress and the immune system. Our review underscores the role of the MGB axis on cognitive aspects of serious mental illnesses with the potential use of agents targeting the gut microbiota as cognitive enhancers. However, the current evidence for clinical trials focused on the MGB axis as cognitive enhancers in these clinical populations is scarce. Future clinical trials using probiotics, prebiotics, antibiotics, or faecal microbiota transplantation need to consider potential mechanistic pathways such as the HPA axis, the immune system, or gut-brain axis hormones involved in appetite control and energy homeostasis.
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5.
Human Breast Milk Composition and Function in Human Health: From Nutritional Components to Microbiome and MicroRNAs.
Yi, DY, Kim, SY
Nutrients. 2021;(9)
Abstract
Human breast milk (HBM) is not only an indispensable source of nutrients for early human growth and development, supplying components that support infant growth and development, but also contains various essential immunologic components with anti-infectious activities and critical roles in the formation of immunity. It is also known that HBM contains its own unique microbiome, including beneficial, commensal, and potentially probiotic bacteria, that can contribute to infant gut colonization. In addition, HBM-derived extracellular vesicles, exosomes, and microRNA are attracting increasing interest for their potential to transfer to the infant and their role in infant development. In this article, we examine some of the various constituents in HBM and review the evidence supporting their associated health effects and their potential applications in human health.
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6.
Perspectives on Existing and Novel Alternative Intravaginal Probiotic Delivery Methods in the Context of Bacterial Vaginosis Infection.
Chandrashekhar, P, Minooei, F, Arreguin, W, Masigol, M, Steinbach-Rankins, JM
The AAPS journal. 2021;(3):66
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Abstract
Bacterial vaginosis (BV) is one of the most common vaginal infections that affects hundreds of millions of women of reproductive age, worldwide. Traditional treatment strategies, such as oral and topical antibiotics, have shown efficacy against BV, but frequent recurrence of infection and the development of antibiotic-resistant bacteria remain as significant challenges. Alternatively, recent progress in understanding immune, microbiological, and metabolic interactions in the vaginal microbiota has prompted the consideration of administering probiotic organisms to restore and maintain vaginal health within the context of BV prevention and treatment. Given this, the objective of this review is to discuss existing and potential alternative approaches to deliver, and to potentially sustain the delivery of probiotics, to prevent and/or treat BV infections. First, a brief overview is provided regarding the probiotic species and combinatorial probiotic strategies that have shown promise in the treatment of BV and in restoring female reproductive health. Additionally, the advantages and challenges associated with current oral and intravaginal probiotic delivery platforms are discussed. Lastly, we present emerging and promising alternative dosage forms, such as electrospun fibers and 3D bioprinted scaffolds, that may be adapted as new strategies to intravaginally deliver probiotic organisms. Graphical abstract.
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7.
Nutrients and Microbiota in Lung Diseases of Prematurity: The Placenta-Gut-Lung Triangle.
Piersigilli, F, Van Grambezen, B, Hocq, C, Danhaive, O
Nutrients. 2020;(2)
Abstract
Cardiorespiratory function is not only the foremost determinant of life after premature birth, but also a major factor of long-term outcomes. However, the path from placental disconnection to nutritional autonomy is enduring and challenging for the preterm infant and, at each step, will have profound influences on respiratory physiology and disease. Fluid and energy intake, specific nutrients such as amino-acids, lipids and vitamins, and their ways of administration -parenteral or enteral-have direct implications on lung tissue composition and cellular functions, thus affect lung development and homeostasis and contributing to acute and chronic respiratory disorders. In addition, metabolomic signatures have recently emerged as biomarkers of bronchopulmonary dysplasia and other neonatal diseases, suggesting a profound implication of specific metabolites such as amino-acids, acylcarnitine and fatty acids in lung injury and repair, inflammation and immune modulation. Recent advances have highlighted the profound influence of the microbiome on many short- and long-term outcomes in the preterm infant. Lung and intestinal microbiomes are deeply intricated, and nutrition plays a prominent role in their establishment and regulation. There is an emerging evidence that human milk prevents bronchopulmonary dysplasia in premature infants, potentially through microbiome composition and/or inflammation modulation. Restoring antibiotic therapy-mediated microbiome disruption is another potentially beneficial action of human milk, which can be in part emulated by pre- and probiotics and supplements. This review will explore the many facets of the gut-lung axis and its pathophysiology in acute and chronic respiratory disorders of the prematurely born infant, and explore established and innovative nutritional approaches for prevention and treatment.
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8.
Population Genetics in the Human Microbiome.
Garud, NR, Pollard, KS
Trends in genetics : TIG. 2020;(1):53-67
Abstract
While the human microbiome's structure and function have been extensively studied, its within-species genetic diversity is less well understood. However, genetic mutations in the microbiome can confer biomedically relevant traits, such as the ability to extract nutrients from food, metabolize drugs, evade antibiotics, and communicate with the host immune system. The population genetic processes by which these traits evolve are complex, in part due to interacting ecological and evolutionary forces in the microbiome. Advances in metagenomic sequencing, coupled with bioinformatics tools and population genetic models, facilitate quantification of microbiome genetic variation and inferences about how this diversity arises, evolves, and correlates with traits of both microbes and hosts. In this review, we explore the population genetic forces (mutation, recombination, drift, and selection) that shape microbiome genetic diversity within and between hosts, as well as efforts towards predictive models that leverage microbiome genetics.
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[Protein arginine deiminase of oral microbiome plays a causal role in the polyarthritis rheumatoid initiating].
Desclos-Theveniau, M, Bonnaure-Mallet, M, Meuric, V
Medecine sciences : M/S. 2020;(5):465-471
Abstract
In the last decade, the association between the periodontitis and rheumatoid arthritis (RA) has been established, suggesting that oral microbiome plays a causal role by initiating this chronic autoimmune inflammatory disease of articulation. Both pathogenesis are similar in term of chronic inflammation, tissue breakdown and bone resorption. Molecular aspects have also revealed that citrullination, a post-translational modification catalyzed by peptidyl-arginine deiminases (PADs), is involved in both diseases. For RA, citrullinated proteins production leads to the synthesis the of anti-citrullinated protein antibodies triggering the loss of immune tolerance. In humans, five PADs have been identified. Recently, studies have found that only Porphyromonas species possess PAD. Thus, a major periodontal pathogen, Porphyromonas gingivalis, is able to generate citrullinated epitopes, and could consequently induce anti-citrullinated protein antibodies. In this review, citrullination process, periodontitis and RA are described to put them in relation with molecular, clinical and epidemiological studies establishing the association between periodontitis and RA.
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10.
Female genital tract microbiota affecting the risk of preterm birth: What do we know so far? A review.
Tsonis, O, Gkrozou, F, Harrison, E, Stefanidis, K, Vrachnis, N, Paschopoulos, M
European journal of obstetrics, gynecology, and reproductive biology. 2020;:168-173
Abstract
Spontaneous Preterm birth (SPTB) is a common obstetric complication affecting 12.9 million births worldwide and is the leading cause of neonatal morbidity and mortality. Disruption in the vaginal microbiota has an impact on the maternal immunological profile leading to SPTBs. Scientists have struggled to link maternal infectious agents with the dysregulation of the maternal immune response in cases of SPTBs. Throughout the last decade, important findings regarding the role of microbiota and its genome, the so-called microbiome, have linked alterations within the population of the microorganisms in our bodies with changes in nutrition, immunity, behaviour and diseases. In this review, evidence regarding the female genital tract microbiota and microbiome has been examined to help further our understanding of its role in disrupting the maternal immune system resulting in spontaneous preterm birth.