Gut Immune System Research Articles

Gut Microbiota and Immune System Dynamics in Parkinson's and Alzheimer's Diseases.

The gut microbiota, a diverse collection of microorganisms in the gastrointestinal tract, plays a critical role in regulating metabolic, immune, and cognitive functions. Disruptions in the composition of these microbial communities, termed dysbiosis, have been linked to various neurodegenerative diseases (NDs), such as Parkinson's disease (PD) and Alzheimer's disease (AD). One of the key pathological features of NDs is neuroinflammation, which involves the activation of microglia and peripheral immune cells. The gut microbiota modulates immune responses through the production of metabolites and interactions with immune cells, influencing the inflammatory processes within the central nervous system. This review explores the impact of gut dysbiosis on neuroinflammation, focusing on the roles of microglia, immune cells, and potential therapeutic strategies targeting the gut microbiota to alleviate neuroinflammatory processes in NDs.

Interconnection of the Gut-Skin Axis in NC/Nga Mouse with Atopic Dermatitis: Effects of the Three Types of Bifidobacterium bifidum CBT-BF3 (Probiotics, Postbiotics, and Cytosine-Phosphate-Guanine Oligodeoxynucleotide) on T Cell Differentiation and Gut Microbiota.

The gut microbiota is an immune system regulator in the gut-skin axis. Dysfunctional interactions between the gut microbiota and the gut immune system can lead to the development of skin diseases such as atopic dermatitis (AD). Probiotics and postbiotics positively affect the balance of the gut microbiota, immune regulation, protection against pathogens, and barrier integrity. This study investigated the effects of probiotic Bifidobacterium bifidum, postbiotic B. bifidum (heat-killed), and cytosine-phosphate-guanine oligodeoxynucleotide (CpG ODN) on the gut microbiota and T cell differentiation in NC/Nga mice induced with AD. 2,4-Dinitrochlorobenzene-induced AD mice had an increased SCORing atopic dermatitis-index and increased mRNA expression levels of Th2 and Th17 cell transcription factors and cytokines, and thymic stromal lymphopoietin (TSLP) cytokine in their mesenteric lymph nodes (mLNs; p<0.05). However, oral administration of the three types of B. bifidum (probiotics, postbiotics, CpG ODN) to AD mice decreased the mRNA expression levels of Th2 and Th17 cell transcription factors and cytokines as well as TSLP cytokine. They increased the mRNA expression levels of regulatory T (Treg) cell transcription factor and cytokine, galectin-9, and filaggrin genes (p<0.05). These effects were more noticeable in the mLNs than in the spleen. In addition, AD mice showed a decrease in Faecalibacterium prausnitzii, Roseburia spp., Leuconostoc citreum, Weissella cibaria, and Weissella koreensis (p<0.05). However, oral administration of the three types of B. bifidum increased Bacteroides spp., Bifidobacterium spp., F. prausnitzii, and Roseburia spp. (p<0.05).

Functional Assessment of a Bioprinted Immuno-Mimetic Peyer's Patch Recapitulating Gut-Associated Lymphoid Tissue.

Gut immune models have attracted much interest in better understanding the microbiome in the human gastrointestinal tract. The gut-associated lymphoid tissue (GALT) has complex structures that interact with microorganisms, including the intestinal monolayer as a physiological barrier and the Peyer's patch (PP) involved in the immune system. Although essential for studying GALT and microbiome interactions, current research often uses simplified models that only recapitulate some components. In this study, GALT is recapitulated to consider the morphology and function of lymphocyte-containing PP beneath the intestinal monolayer and to analyze microbiome interaction. Using the bioprinting technique, a dome-shaped structure array for the PP is fabricated, and epithelial cells are cocultured to form the intestinal monolayer. The developed GALT model shows stable cell differentiation on the hydrogel while exhibiting durability against lipopolysaccharides. It also exhibits increased responsiveness to Escherichia coli, as indicated by elevated nitric oxide levels. In addition, the model underscores the critical role of GALT in maintaining bacterial coexistence and in facilitating immune defense against foreign antigens through the secretion of immunoglobulin A by lymphocyte spheroids. The proposed GALT model is expected to provide significant insights into studying the gut-immune system complexity and microbiome.

The pyruvate–GPR31 axis promotes transepithelial dendrite formation in human intestinal dendritic cells

The intestinal lumen is rich in gut microbial metabolites that serve as signaling molecules for gut immune cells. G-protein-coupled receptors (GPCRs) sense metabolites and can act as key mediators that translate gut luminal signals into host immune responses. However, the impacts of gut microbe-GPCR interactions on human physiology have not been fully elucidated. Here, we show that GPR31, which is activated by the gut bacterial metabolite pyruvate, is specifically expressed on type 1 conventional dendritic cells (cDC1s) in the lamina propria of the human intestine. Using human induced pluripotent stem cell-derived cDC1s and a monolayer human gut organoid coculture system, we show that cDC1s extend their dendrites toward pyruvate on the luminal side, forming transepithelial dendrites (TED). Accordingly, GPR31 activation via pyruvate enhances the fundamental function of cDC1 by allowing efficient uptake of gut luminal antigens, such as dietary compounds and bacterial particles through TED formation. Our results highlight the role of GPCRs in tuning the human gut immune system according to local metabolic cues.

Gestational diabetes exacerbates intrauterine microbial exposure induced intestinal microbiota change in offspring contributing to increased immune response.

maternal health during pregnancy can affect the intestinal microbial community of offspring, but currently the impact of intrauterine environmental changes resulting from gestational diabetes mellitus (GDM) on the microbiota of offspring as well as its interaction with the immune system remains unclear. to explore the impact of intrauterine microbial exposure during pregnancy of gestational diabetes mellitus on the development of neonate's intestinal microbiota and activation of immune responses. Levels of lipopolysaccharides in cord blood from GDM and expression of microbial recognition-related proteins in the placenta were measured. To evaluate embryonic intestinal colonization, pregnant mice with GDM were administered with labeled Escherichia coli or Lactobacillus. The intestinal colonization of pups was analyzed through 16S rRNA gene sequencing and labeled microbial culture. Additionally, memory T lymphocyte and dendritic cell co-culture experiments were conducted to elucidate the immune memory of intestinal microbes during the embryonic stages. Gestational diabetes mellitus led to elevated umbilical cord blood LPS level and increased GFP labeled Escherichia coli in the offspring's intestine after gestational microbial exposure. The mouse model of GDM exhibited increased immune markers including TLR4, TLR5, IL-22 and IL-23 in the placenta and a recall response from memory T cells in offspring's intestines, with similar observations found in human experiments. Furthermore, reduced intestinal microbiome diversity and an increased ratio of Firmicutes/Bacteroidetes was found in GDM progeny, with the stability of bacterial colonization been interfered. Our investigation has revealed a noteworthy correlation between gestational diabetes and intrauterine microbial exposure, as well as alterations in the neonatal microbiota and activation of immune responses. These findings highlight the gestational diabetes's role on offspring's gut microbiota and immune system interactions with early-life pathogen exposure.

Layer segmented filamentous bacteria colonize and impact gut health of broiler chickens.

In commercial poultry farms, chicks hatch away from their progenitors from which they acquire key host-specific microbiota, like segmented filamentous bacteria (SFB) involved in gut maturation in early life. This study investigated whether providing chicken SFB to newly hatched broilers would increase their gut maturation and resistance to bacteria relevant to broiler and human health. One-day-old Ross308 broilers were orally treated with either phosphate-buffered saline (CON) or layer-derived SFB (D-SFB). On days 5, 10, 17, and 24, feces were collected to detect and enumerate SFB and Enterobacteriaceae. On days 8, 15, 22, and 29, birds were euthanized, intestinal samples were collected to detect and enumerate SFB through quantitative PCR (qPCR) and microscopy and expression of genes associated with gut immune function through reverse transcription-qPCR. This study showed that, despite their host specificity, layer SFB can colonize their genetically distinct relative broilers. Ileal SFB colonization was accelerated by a week with the SFB treatment and covered the proximal, medial, and distal sections of the ileum. Colonization of the ileum by SFB in early life highly activated gene expression of intestinal barrier proteins and cytokines, e.g., IL-10 and IFNγ but not IL-17. SFB treatment reduced the level of Enterobacteriaceae in the gut and provided superior resistance to intestinal and extraintestinal pathogens as tested in vitro. Overall, early gut colonization of SFB is imperative for the maturation of the gut immune system and the establishment of a homeostatic gut environment. Improving our understanding of gut immune maturation in food-producing animals is crucial for both human and animal health.IMPORTANCEIn commercial farms, newly hatched chicks may lack host-specific microbiota that help mature their gut immune system for lifelong health benefits. Here, introducing an avian segmented filamentous bacteria (SFB) to commercially sourced chickens orally at hatch accelerated SFB colonization of the ileum. Remarkably, SFB from layers were able to colonize broilers and enhance gut immune maturation, and this immunomodulation impacted the ability to increase intestinal and extraintestinal resistance to bacteria relevant to poultry and human health. With the antibiotic restrictions in animal production, strategies that will help mitigate infections are urgently needed. In summary, we developed a live prophylactic for newly hatched chicks to improve animal health and food safety. Due to the host specificity of SFB, our data highlight the importance of investigating the molecular mechanism of SFB interaction in their own host.

Impact of obesity on allergic respiratory diseases and on mental and cognitive performance

Summary Background Obesity and allergies are among the most common diseases of our civilization. Given the simultaneous rise in the prevalence of these diseases in recent years, a potential causal link between the two has been proposed. In particular, obese patients are at an increased risk of developing bronchial asthma, likely due to mechanical restrictions but also to metabolic changes that adversely affect immune function. Neuroscience studies have also shown that obesity can lead to impaired brain function and mental health. In the following review, we will take a closer look at our studies that focus on the influence of obesity on allergic diseases and cognitive performance. Results Both human studies and animal models (mice) have shown that obesity leads to increased allergic responses in the airways. Our studies in a mouse model of obesity confirm that an obese phenotype is associated with increased allergic sensitization and manifestation. These changes are associated with significant shifts in the composition of the gut microbial flora. The microbiome changes are further associated with allergic airway inflammation and an increased incidence of T helper 1 (Th1) type pulmonary macrophages. Interestingly, despite the changes in the microbiome, it is possible to effectively prevent allergy development by inducing oral tolerance. Furthermore, it was observed that obese mice show increased signs of anxiety and depression, as well as reduced cognitive performance. Conclusion Obesity is a complex metabolic disease that significantly impacts our body’s gut microbiome and immune system, resulting in an increased incidence of allergic asthma and neurological/psychological changes. Attention should be given to both the prophylactic and therapeutic measures to mitigate the impact of obesity, including oral tolerance for managing existing allergic diseases.

Exploring Dietary Interventions in Autism Spectrum Disorder.

Autism spectrum disorder (ASD) involves social communication difficulties and repetitive behaviors, and it has a growing prevalence worldwide. Symptoms include cognitive impairments, gastrointestinal (GI) issues, feeding difficulties, and psychological problems. A significant concern in ASD is food selectivity, leading to nutrient deficiencies. Common GI issues in ASD, such as constipation and irritable bowel syndrome, stem from abnormal gut flora and immune system dysregulation. Sensory sensitivities and behavioral challenges exacerbate these problems, correlating with neurological symptom severity. Children with ASD also exhibit higher oxidative stress due to low antioxidant levels like glutathione. Therapeutic diets, including ketogenic, high-antioxidant, gluten-free and casein-free, and probiotic-rich diets, show potential in managing ASD symptoms like behavior, communication, GI issues, and oxidative stress, though the evidence is limited. Various studies have focused on different populations, but there is increasing concern about the impact among children. This review aims to highlight the food preferences of the ASD population, analyze the effect of the physicochemical and nutritional properties of foods on the selectivity in its consumption, GI problems, and antioxidant deficiencies in individuals with ASD, and evaluate the effectiveness of therapeutic diets, including diets rich in antioxidants, gluten-free and casein-free, ketogenic and essential fatty acids, and probiotic-rich diets in managing these challenges.

Characterization of giant endocrine cells in the fundic stomach of African catfish (Clarias gariepinus) demonstrated by histochemical, immunohistochemical and ultrastructure microscopy methods suggesting their role in immunity

Endocrine cells in the fundic stomach of Clarias gariepinus were characterized in this work using transmission electron microscopy, immunohistochemistry, and histochemistry. Performic acid mixed with alcian blue pH2.5 and silver stain were among the histochemical stains used for endocrine cells. Endocrine cells can be found in the epithelium, lamina propria, submucosa, muscular layer, serosa, and the area between the stomach glands. Endocrine cells with one or more nuclei were found. Endocrine cells were studied using CD3, CD21, and CD68 in an immunohistochemistry analysis. The expression of the lymphocyte marker CD3 by endocrine cells is remarkable. In addition, they had a strong immunological response to CD21 and CD68, which are characteristics of phagocytic cells. Granules of varied sizes and electron densities are packed densely into the cytoplasm of the cells, as seen by transmission electron microscopy. We propose that endocrine cells play a crucial role in immune defense. The role of endocrine cells in the gut’s immune system is an area that needs further investigation.

Closed-loop theranostic microgels for immune microenvironment modulation and microbiota remodeling in ulcerative colitis

Inflammatory bowel disease (IBD) is characterized by the upregulation of reactive oxygen species (ROS) and dysfunction of gut immune system, and microbiota. The conventional treatments mainly focus on symptom control with medication by overuse of drugs. There is an urgent need to develop a closed-loop strategy that combines in situ monitoring and precise treatment. Herein, we innovatively designed the ‘cluster munition structure’ theranostic microgels to realize the monitoring and therapy for ulcerative colitis (a subtype of IBD). The superoxide anion specific probe (tetraphenylethylene-coelenterazine, TPC) and ROS-responsive nanogels consisting of postbiotics urolithin A (UA) were loaded into alginate and ion-crosslinked to obtain the theranostic microgels. The theranostic microgels could be delivered to the inflammatory site, where the environment-triggered breakup of the microgels and release of the nanogels were achieved in sequence. The TPC-UA group had optimal results in reducing inflammation, repairing colonic epithelial tissue, and remodeling microbiota, leading to inflammation amelioration and recovery of tight junction between the colonic epithelium, and maintenance of gut microbiota. During the recovery process, the local chemiluminescence intensity, which is proportional to the degree of inflammation, was gradually inhibited. The cluster munition of theranostic microgels displayed promising outcomes in monitoring inflammation and precise therapy, and demonstrated the potential for inflammatory disease management.

Neuroimmune Crossroads: The Interplay of the Enteric Nervous System and Intestinal Macrophages in Gut Homeostasis and Disease.

A defining unique characteristic of the gut immune system is its ability to respond effectively to foreign pathogens while mitigating unnecessary inflammation. Intestinal macrophages serve as the cornerstone of this balancing act, acting uniquely as both the sword and shield in the gut microenvironment. The GI tract is densely innervated by the enteric nervous system (ENS), the intrinsic nervous system of the gut. Recent advances in sequencing technology have increasingly suggested neuroimmune crosstalk as a critical component for homeostasis both within the gut and in other tissues. Here, we systematically review the ENS-macrophage axis. We focus on the pertinent molecules produced by the ENS, spotlight the mechanistic contributions of intestinal macrophages to gut homeostasis and inflammation, and discuss both existing and potential strategies that intestinal macrophages use to integrate signals from the ENS. This review aims to elucidate the complex molecular basis governing ENS-macrophage signaling, highlighting their cooperative roles in sustaining intestinal health and immune equilibrium.

Ultra-processed foods, allergy outcomes and underlying mechanisms in children: An EAACI task force report.

Consumption of ultra-processed foods [UPFs] may be associated with negative health outcomes. Limited data exist regarding the potential role of UPFs in the occurrence of allergic diseases. The underlying mechanisms underpinning any such associations are also poorly elucidated. We performed a systematic review and narrative evidence synthesis of the available literature to assess associations between UPF consumption and pediatric allergy outcomes (n = 26 papers), including data on the association seen with the gut microbiome (n = 16 papers) or immune system (n = 3 papers) structure and function following PRISMA guidelines. Dietary exposure to fructose, carbonated soft drinks, and sugar intake was associated with an increased risk of asthma, allergic rhinitis, and food allergies in children. Commercial baby food intake was associated with childhood food allergy. Childhood intake of fructose, fruit juices, sugar-sweetened beverages, high carbohydrate UPFs, monosodium glutamate, UPFs, and advanced glycated end-products (AGEs) was associated with the occurrence of allergic diseases. Exposure to UPFs and common ingredients in UPFs seem to be associated with increased occurrence of allergic diseases such as asthma, wheezing, food allergies, atopic dermatitis, and allergic rhinitis, in many, but not all studies. More preclinical and clinical studies are required to better define the link between UPF consumption and the risk of allergies and asthma. These observational studies ideally require supporting data with clearly defined UPF consumption, validated dietary measures, and mechanistic assessments to definitively link UPFs with the risk of allergies and asthma.

EarlyLife - Gut epithelial dynamics and function at the nexus of early life infection and longterm health

We spoke with Prof. Dr. Mathias Hornef about the ERC-funded EarlyLife project, which investigates how early-life infections impact the gut epithelium, microbiome, and immune system development in neonates. Using advanced techniques and mouse models, the project aims to uncover the influence of these infections on long-term health and disease susceptibility.

High-Salt Diet and Intestinal Microbiota: Influence on Cardiovascular Disease and Inflammatory Bowel Disease.

Salt, or sodium chloride, is an essential component of the human diet. Recent studies have demonstrated that dietary patterns characterized by a high intake of salt can influence the abundance and diversity of the gut microbiota, and may play a pivotal role in the etiology and exacerbation of certain diseases, including inflammatory bowel disease and cardiovascular disease. The objective of this review is to synthesize the effects of elevated salt consumption on the gut microbiota, including its influence on gut microbial metabolites and the gut immune system. Additionally, this review will investigate the potential implications of these effects for the development of cardiovascular disease and inflammatory bowel disease. The findings of this study offer novel insights and avenues for the management of two common conditions with significant clinical implications.

Antimicrobial resistance: use of phage therapy in the management of resistant infections.

The emergence and increase in antimicrobial resistance (AMR) is now widely recognized as a major public health challenge. Traditional antimicrobial drugs are becoming increasingly ineffective, while the development of new antibiotics is waning. As a result, alternative treatments for infections are garnering increased interest. Among these alternatives, bacteriophages, also known as phages, are gaining renewed attention and are reported to offer a promising solution to alleviate the burden of bacterial infections. This review discusses the current successes of phage therapy (PT) against multidrug-resistant organisms (MDROs), such as Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, and Enterobacter spp. The review also compares the efficacy of PT with that of chemical antibiotics, reporting on its benefits and limitations, while highlighting its impact on the human gut microbiome and immune system. Despite its potential, phage therapy is reported to face challenges such as the narrow antibacterial range, the complexity of developing phage cocktails, and the need for precise dosing and duration protocols. Nevertheless, continued research, improved regulatory frameworks, and increased public awareness are essential to realize its full potential and integration into standard medical practice, paving the way for innovative treatments that can effectively manage infections in an era of rising antimicrobial resistance.

Gut Microbiota, Deranged Immunity, and Hepatocellular Carcinoma.

Liver cancer, particularly hepatocellular carcinoma (HCC), is a significant gastrointestinal disease with a mortality rate as high as nearly 80% within five years. The disease's pathophysiology involves deranged immune responses and bile acid metabolism, with the gut microbiota (GM) playing a crucial role. Recent research highlights the potential of GM in influencing HCC treatment outcomes, especially regarding immune checkpoint inhibitors (ICIs). However, few patients currently benefit from ICIs due to a lack of effective response biomarkers. This review aimed to explore the literature on HCC treatment issues, focusing on immune response, bile acid metabolism, and GM dysbiosis. This review included studies from PubMed, Medline, and major gastroenterology and hepatology meetings, using keywords like gut microbiota, immune system, liver cancer, and checkpoint inhibitors. GM dysbiosis significantly impacts immune response and bile acid metabolism, making it a promising biomarker for ICI response. Modulating GM can enhance ICI treatment efficacy, although more research is needed to confirm its direct therapeutic benefits for HCC. GM dysbiosis is integral to liver cancer pathogenesis and treatment response. Its modulation offers promising therapeutic avenues for improving HCC prognosis and response to immunotherapy.

Effect of probiotics on hematology and histopathology of organs associated with immune system in male and female Wistar rats

In the present study, potential probiotics were isolated from dairy products and characterized on a molecular basis. Male and female (16 + 16, n = 4) Wistar rats were randomly assigned to 5 groups to revise the effects of isolated potential probiotics on the gut immune system: 0-day, negative control, positive control (commercial product Lactobacillus acidophilus-14), laboratory isolated strains Pro-3 (Weissella confusa MZ735961), and Pro-4 (Lactiplantibacillus plantarum MZ727611). Aspartate-aminotransferase, Interleukin-6, bilirubin, and Alanine-transaminase values in both genders were expected but AST and creatinine values had a minor increase in the female group compared to the male probiotic-treated group. Cellular blood count level of mean corpuscular hemoglobin in male groups showed no considerable differences (p = 0.95), while there were decreased differences (p = 0.00) in female groups. The level of mean corpuscular hemoglobin concentration (MCHC) showed distinct variations (p = 0.02) in male groups, while these values were insignificant changes (p > 0.05) among female groups. No damage to the liver, thymus, or colon was ascertained based on morphological findings. The colon wall thickness, external muscle, crypt depth, and mucosa were significantly (p = 0.03) improved in rats given potential probiotics. In conclusion, probiotic supplementation stimulates the immune system. It may protect the intestinal mucosa by strengthening the gut’s immune system and promoting intestinal efficiency (nutrient absorption and number of goblet cells). L. plantarum can therefore offer a reliable, affordable, and safe treatment for functional gastrointestinal illnesses.

The Relationship between Canine Behavioral Disorders and Gut Microbiome and Future Therapeutic Perspectives.

Canine behavioral disorders have become one of the most common concerns and challenging issues among dog owners. Thus, there is a great demand for knowledge about various factors affecting dogs' emotions and well-being. Among them, the gut-brain axis seems to be particularly interesting, especially since in many instances the standard treatment or behavioral therapies insufficiently improve animal behavior. Therefore, to face this challenge, the search for novel therapeutic methods is highly required. Existing data show that mammals' gut microbiome, immune system, and nervous system are in continuous communication and influence animal physiology and behavior. This review aimed to summarize and discuss the most important scientific evidence on the relationship between mental disorders and gut microbiota in dogs, simultaneously presenting comparable outcomes in humans and rodent models. A comprehensive overview of crucial mechanisms of the gut-brain axis is included. This refers especially to the neurotransmitters crucial for animal behavior, which are regulated by the gut microbiome, and to the main microbial metabolites-short-chain fatty acids (SCFAs). This review presents summarized data on gut dysbiosis in relation to the inflammation process within the organism, as well as the activation of the hypothalamic-pituitary-adrenal (HPA) axis. All of the above mechanisms are presented in this review in strict correlation with brain and/or behavioral changes in the animal. Additionally, according to human and laboratory animal studies, the gut microbiome appears to be altered in individuals with mental disorders; thus, various strategies to manipulate the gut microbiota are implemented. This refers also to the fecal microbiome transplantation (FMT) method, based on transferring the fecal matter from a donor into the gastrointestinal tract of a recipient in order to modulate the gut microbiota. In this review, the possible effects of the FMT procedure on animal behavioral disorders are discussed.

Mapping knowledge landscapes and research frontiers of gastrointestinal microbiota and bone metabolism: a text-mining study.

Extensive research efforts have been dedicated to elucidating the intricate pathways by which gastrointestinal microbiota and their metabolites exert influence on the processes of bone formation. Nonetheless, a notable gap exists in the literature concerning a bibliometric analysis of research trends at the nexus of gastrointestinal microbiota and bone metabolism. To address this scholarly void, the present study employs a suite of bibliometric tools including online platforms, CiteSpace and VOSviewer to scrutinize the pertinent literature in the realm of gastrointestinal microbiota and bone metabolism. Examination of the temporal distribution of publications spanning from 2000 to 2023 reveals a discernible upward trajectory in research output, characterized by an average annual growth rate of 19.2%. Notably, China and the United States emerge as primary contributors. Predominant among contributing institutions are Emory University, Harvard University, and the University of California. Pacifici R from Emory University contributed the most research with 15 publications. In the realm of academic journals, Nutrients emerges as the foremost publisher, followed closely by Frontiers in Microbiology and PLOS One. And PLOS One attains the highest average citations of 32.48. Analysis of highly cited papers underscores a burgeoning interest in the therapeutic potential of probiotics or probiotic blends in modulating bone metabolism by augmenting host immune responses. Notably, significant research attention has coalesced around the therapeutic interventions of probiotics, particularly Lactobacillus reuteri, in osteoporosis, as well as the role of gastrointestinal microbiota in the etiology and progression of osteoarthritis. Keyword analysis reveals prevalent terms including gut microbiota, osteoporosis, bone density, probiotics, inflammation, SCFAs, metabolism, osteoarthritis, calcium absorption, obesity, double-blind, prebiotics, mechanisms, postmenopausal women, supplementation, risk factors, oxidative stress, and immune system. Future research endeavors warrant a nuanced exploration of topics such as inflammation, obesity, SCFAs, postmenopausal osteoporosis, skeletal muscle, oxidative stress, double-blind trials, and pathogenic mechanisms. In summary, this study presents a comprehensive bibliometric analysis of global research on the interplay between gastrointestinal microbiota and bone metabolism, offering valuable insights for scholars, particularly nascent researchers, embarking on analogous investigations within this domain.

The Role of Breastfeeding in Acute Respiratory Infections in Infancy.

Acute respiratory infections (ARIs) affect the respiratory tract, are often caused by viruses such as respiratory syncytial virus and rhinovirus, and present symptoms such as coughing, fever, respiratory distress, and breathing difficulty. The global adherence to exclusive breastfeeding (BF) for the first 6 months of life has reached 44%, supported by the World Health Organization and United Nations International Children's Emergency Fund efforts. BF provides vital nutrients and contributes to infant immune system development, protecting against infections. The role of BF in preventing and reducing complications of ARIs in infants is gaining attention, prompting a review of current data and future research needs. This review aims to summarize the evidence on the role of BF in reducing the risk and severity of ARIs in infants, elucidate the adaptations in breast milk composition during infections, and identify relevant research needs. Human milk (HM) is rich in immunoglobulins, antimicrobial peptides, and immunomodulatory factors that protect against various pathogens, including respiratory viruses. Several studies have demonstrated that BF is associated with a significant reduction in hospitalization, oxygen requirements, and mortality in infants with ARIs. The effectiveness of BF varies according to the specific respiratory virus, and a longer duration of exclusive BF appears to enhance its protective effect. It is documented that the composition of HM adjusts dynamically in response to infections, fortifying the infant's immune defenses. Specific immunological components of HM, including leukocytes and immunoglobulins, increase in response to infection in the infant, contributing to the enhancement of the immune defense in infants. Immune-boosting microRNAs enhance immune transfer to the infants and promote early gut maturation, and the HM microbiome along with other factors modifies the infant's gut microbiome and immune system. BF defends infants from respiratory infections, and the investigation of the microRNAs in HM offers new insights into its antiviral properties. The promotion of BF, especially in vulnerable communities, is of paramount importance in alleviating the global burden of ARIs in infancy.