Gut-Brain Axis: Focus on Sex Differences in Neuroinflammation.

In recent years, there has been a growing interest in the concept of the "gut-brain axis". In addition to well-studied diseases associated with an imbalance in gut microbiota, such as cancer, chronic inflammation, and cardiovascular diseases, research is now exploring the potential role of gut microbial dysbiosis in the onset and development of brain-related diseases. When the function of the intestinal barrier is altered by dysbiosis, the aberrant immune system response interacts with the nervous system, leading to a state of "neuroinflammation". The gut microbiota-brain axis is mediated by inflammatory and immunological mechanisms, neurotransmitters, and neuroendocrine pathways. This narrative review aims to illustrate the molecular basis of neuroinflammation and elaborate on the concept of the gut-brain axis by virtue of analyzing the various metabolites produced by the gut microbiome and how they might impact the nervous system. Additionally, the current review will highlight how sex influences these molecular mechanisms. In fact, sex hormones impact the brain-gut microbiota axis at different levels, such as the central nervous system, the enteric nervous one, and enteroendocrine cells. A deeper understanding of the gut-brain axis in human health and disease is crucial to guide diagnoses, treatments, and preventive interventions.

Changes in Lymphocyte Subpopulations after Remdesivir Therapy for COVID-19: A Brief Report.

Remdesivir (RDV) has demonstrated clinical benefit in hospitalized COronaVIrus Disease (COVID)-19 patients. The objective of this brief report was to assess a possible correlation between RDV therapy and the variation in lymphocyte subpopulations. We retrospectively studied 43 hospitalized COVID-19 patients: 30 men and 13 women (mean age 69.3 ± 15 years); 9/43 had received RDV therapy. Six patients had no need for oxygen (severity group 0); 22 were on oxygen treatment with a fraction of inspired oxygen (FiO2) ≤ 50% (group 1); 7 on not-invasive ventilation (group 2); 3 on invasive mechanical ventilation (group 3); and 5 had died (group 4). Cytofluorimetric assessment of lymphocyte subpopulations showed substantial changes after RDV therapy: B lymphocytes and plasmablasts were significantly increased (p = 0.002 and p = 0.08, respectively). Cytotoxic T lymphocytes showed a robust reduction (p = 0.008). No changes were observed in CD4+-T cells and natural killers (NKs). There was a significant reduction in regulatory T cells (Tregs) (p = 0.02) and a significant increase in circulating monocytes (p = 0.03). Stratifying by disease severity, after RDV therapy, patients with severity 0-2 had significantly higher B lymphocyte and monocyte counts and lower memory and effector cytotoxic T cell counts. Instead, patients with severity 3-4 had significantly higher plasmablast and lower memory T cell counts. No significant differences for CD4+-T cells, Tregs, and NKs were observed. Our brief report showed substantial changes in the lymphocyte subpopulations analyzed between patients who did not receive RDV therapy and those after RDV treatment. Despite the small sample size, due to the retrospective nature of this brief report, the substantial changes in lymphocyte subpopulations reported could lead to speculation on the role of RDV treatment both on immune responses against the virus and on the possible downregulation of the cytokine storm observed in patients with more severe disease.

The Interplay between Helicobacter pylori and Gut Microbiota in Non-Gastrointestinal Disorders: A Special Focus on Atherosclerosis.

The discovery of Helicobacter pylori (H. pylori) in the early 1980s by Nobel Prize winners in medicine Robin Warren and Barry Marshall led to a revolution in physiopathology and consequently in the treatment of peptic ulcer disease. Subsequently, H. pylori has also been linked to non-gastrointestinal diseases, such as autoimmune thrombocytopenia, acne rosacea, and Raynaud's syndrome. In addition, several studies have shown an association with cardiovascular disease and atherosclerosis. Our narrative review aims to investigate the connection between H. pylori infection, gut microbiota, and extra-gastric diseases, with a particular emphasis on atherosclerosis. We conducted an extensive search on PubMed, Google Scholar, and Scopus, using the keywords "H. pylori", "dysbiosis", "microbiota", "atherosclerosis", "cardiovascular disease" in the last ten years. Atherosclerosis is a complex condition in which the arteries thicken or harden due to plaque deposits in the inner lining of an artery and is associated with several cardiovascular diseases. Recent research has highlighted the role of the microbiota in the pathogenesis of this group of diseases. H. pylori is able to both directly influence the onset of atherosclerosis and negatively modulate the microbiota. H. pylori is an important factor in promoting atherosclerosis. Progress is being made in understanding the underlying mechanisms, which could open the way to interesting new therapeutic perspectives.

The Interplay between Immunity and Microbiota at Intestinal Immunological Niche: The Case of Cancer.

The gut microbiota is central to the pathogenesis of several inflammatory and autoimmune diseases. While multiple mechanisms are involved, the immune system clearly plays a special role. Indeed, the breakdown of the physiological balance in gut microbial composition leads to dysbiosis, which is then able to enhance inflammation and to influence gene expression. At the same time, there is an intense cross-talk between the microbiota and the immunological niche in the intestinal mucosa. These interactions may pave the way to the development, growth and spreading of cancer, especially in the gastro-intestinal system. Here, we review the changes in microbiota composition, how they relate to the immunological imbalance, influencing the onset of different types of cancer and the impact of these mechanisms on the efficacy of traditional and upcoming cancer treatments.

The Intricate Link among Gut "Immunological Niche," Microbiota, and Xenobiotics in Intestinal Pathology.

Inflammatory bowel diseases (IBDs) are diseases characterized by various degrees of inflammation involving the gastrointestinal tract. Ulcerative colitis and Crohn's disease are characterized by a dysregulated immune response leading to structural gut alterations in genetically predisposed individuals. Diverticular disease is characterized by abnormal immune response to normal gut microbiota. IBDs are linked to a lack of physiological tolerance of the mucosal immune system to resident gut microbiota and pathogens. The disruption of immune tolerance involves inflammatory pathways characterized by an unbalance between the anti-inflammatory regulatory T cells and the proinflammatory Th1/Th17 cells. The interaction among T cell subpopulations and their related cytokines, mediators of inflammation, gut microbiota, and the intestinal mucosa constitute the gut "immunological niche." Several evidences have shown that xenobiotics, such as rifaximin, can positively modulate the inflammatory pathways at the site of gut immunological niche, acting as anti-inflammatory agents. Xenobiotics may interfere with components of the immunological niche, leading to activation of anti-inflammatory pathways and inhibition of several mediators of inflammation. In summary, xenobiotics may reduce disease-related gut mucosal alterations and clinical symptoms. Studying the complex interplay between gut immunological niche and xenobiotics will certainly open new horizons in the knowledge and therapy of intestinal pathologies.

Obscure recurrent gastrointestinal bleeding: a revealed mystery?

OBJECTIVE: Nowadays, capsule endoscopy (CE) is the first-line procedure after negative upper and lower gastrointestinal (GI) endoscopy for obscure gastrointestinal bleeding (OGIB). Approximately, two-thirds of patients undergoing CE for OGIB will have a small-bowel abnormality. However, several patients who underwent CE for OGIB had the source of their blood loss in the stomach or in the colon. The aim of the present study is to determine the incidence of bleeding lesions missed by the previous gastroscopy/colonoscopy with CE and to evaluate the indication to repeat a new complete endoscopic workup in subjects related to a tertiary center for obscure bleeding before CE. METHODS AND METHODS: We prospectively reviewed data from 637/1008 patients underwent to CE for obscure bleeding in our tertiary center after performing negative gastroscopy and colonoscopy. RESULTS: CE revealed a definite or likely cause of bleeding in stomach in 138/637 patients (yield 21.7%) and in the colon in 41 patients (yield 6.4%) with a previous negative gastroscopy and colonoscopy, respectively. The lesions found were outside the small bowel in only 54/637 (8.5%) patients. In 111/138 patients, CE found lesions both in stomach and small bowel (small-bowel erosions in 54, AVMs in 45, active small-bowel bleeding in 4, neoplastic lesions in 3 and distal ileum AVMs in 5 patients). In 24/41 (58.5%) patients, CE found lesions both in small bowel and colon (multiple small-bowel erosions in 15; AVMs in 8 and neoplastic lesion in 1 patients. All patients underwent endoscopic therapy or surgery for their nonsmall-bowel lesions. CONCLUSIONS: Lesions in upper or lower GI tract have been missed in about 28% of patients submitted to CE for obscure bleeding. CE may play an important role in identifying lesions missed at conventional endoscopy.

Pollutants, microbiota and immune system: frenemies within the gut.

Pollution is a critical concern of modern society for its heterogeneous effects on human health, despite a widespread lack of awareness. Environmental pollutants promote several pathologies through different molecular mechanisms. Pollutants can affect the immune system and related pathways, perturbing its regulation and triggering pro-inflammatory responses. The exposure to several pollutants also leads to alterations in gut microbiota with a decreasing abundance of beneficial microbes, such as short-chain fatty acid-producing bacteria, and an overgrowth of pro-inflammatory species. The subsequent intestinal barrier dysfunction, together with oxidative stress and increased inflammatory responses, plays a role in the pathogenesis of gastrointestinal inflammatory diseases. Moreover, pollutants encourage the inflammation-dysplasia-carcinoma sequence through various mechanisms, such as oxidative stress, dysregulation of cellular signalling pathways, cell cycle impairment and genomic instability. In this narrative review, we will describe the interplay between pollutants, gut microbiota, and the immune system, focusing on their relationship with inflammatory bowel diseases and colorectal cancer. Understanding the biological mechanisms underlying the health-to-disease transition may allow the design of public health policies aimed at reducing the burden of disease related to pollutants.

The Impact of Climate Change on Immunity and Gut Microbiota in the Development of Disease.

According to the definition provided by the United Nations, "climate change" describes the persistent alterations in temperatures and weather trends. These alterations may arise naturally, such as fluctuations in the solar cycle. Nonetheless, since the 19th century, human activities have emerged as the primary agent for climate change, primarily attributed to the combustion of fossil fuels such as coal, oil, and gas. Climate change can potentially influence the well-being, agricultural production, housing, safety, and employment opportunities for all individuals. The immune system is an important interface through which global climate change affects human health. Extreme heat, weather events and environmental pollutants could impair both innate and adaptive immune responses, promoting inflammation and genomic instability, and increasing the risk of autoimmune and chronic inflammatory diseases. Moreover, climate change has an impact on both soil and gut microbiome composition, which can further explain changes in human health outcomes. This narrative review aims to explore the influence of climate change on human health and disease, focusing specifically on its effects on the immune system and gut microbiota. Understanding how these factors contribute to the development of physical and mental illness may allow for the design of strategies aimed at reducing the negative impact of climate and pollution on human health.

Immune Cells, Gut Microbiota, and Vaccines: A Gender Perspective.

The development of preventive and therapeutic vaccines has played a crucial role in preventing infections and treating chronic and non-communicable diseases, respectively. For a long time, the influence of sex differences on modifying health and disease has not been addressed in clinical and preclinical studies. The interaction of genetic, epigenetic, and hormonal factors plays a role in the sex-related differences in the epidemiology of diseases, clinical manifestations, and the response to treatment. Moreover, sex is one of the leading factors influencing the gut microbiota composition, which could further explain the different predisposition to diseases in men and women. In the same way, differences between sexes occur also in the immune response to vaccines. This narrative review aims to highlight these differences, focusing on the immune response to vaccines. Comparative data about immune responses, vaccine effectiveness, and side effects are reviewed. Hence, the intricate interplay between sex, immunity, and the gut microbiota will be discussed for its potential role in the response to vaccination. Embracing a sex-oriented perspective in research may improve the efficacy of the immune response and allow the design of tailored vaccine schedules.

Mediterranean Diet Influence on SARS-CoV-2 Vaccine Adverse Reaction: Friend or Foe?

BACKGROUND: The Mediterranean Diet (MedDiet) has long been recognized for its health-promoting attributes, with proven benefits in preventing cardiovascular and metabolic diseases. During the global COVID-19 pandemic, MedDiet's potential to mitigate the impact of SARS-CoV-2 infection gained attention. This study aims to investigate the interplay among MedDiet adherence, immune system response to SARS-CoV-2 vaccines, and potential sex-related variations. METHODS: A retrospective observational study was conducted through collecting data from a web survey for the Italian population. Adherence to the MedDiet was assessed using the Mediterranean Diet Adherence Screener (MEDAS); in addition, COVID-19 symptoms and vaccination details were also obtained. RESULTS: Significant associations between MedDiet adherence, COVID-19 symptoms, and vaccine-related side effects were observed. Notably, females demonstrated distinct responses, reporting lymph node enlargement and a different prevalence and severity of vaccine side effects compared to males. CONCLUSIONS: This study highlights the protective role of the MedDiet against COVID-19 and emphasizes the relevance of sex-specific responses in vaccination outcomes according to MEDAS score.

Hypovitaminosis D and Leukocytosis to Predict Cardiovascular Abnormalities in Children with Kawasaki Disease: Insights from a Single-Center Retrospective Observational Cohort Study.

Introduction: An aberrant immune response involving yet unidentified environmental and genetic factors plays a crucial role in triggering Kawasaki disease (KD). Aims: The aim of this study was to assess general and laboratory data at the onset of KD in a single-center cohort of children managed between 2003 and 2023 and retrospectively evaluate any potential relationship with the development of KD-related cardiovascular abnormalities (CVAs). Patients and methods: We took into account a total of 65 consecutive children with KD (42 males, median age: 22 months, age range: 2-88 months) followed at the Department of Life Sciences and Public Health in our University; demographic data, clinical signs, and laboratory variables at disease onset, before IVIG infusion, including C-reactive protein, hemoglobin, white blood cell (WBC) count, neutrophil count, platelet count, aminotransferases, natremia, albumin, total bilirubin, and 25-hydroxyvitamin D were evaluated. Results: Twenty-one children (32.3% of the whole cohort) were found to have echocardiographic evidence of CVAs. Univariate analysis showed that diagnosis of KD at <1 year or >5 years was associated with CVAs (p = 0.001 and p = 0.01, respectively); patients with CVAs had a longer fever duration and mostly presented atypical or incomplete presentations. Interestingly, all patients with CVAs had lower levels of vitamin D (less than 30 mg/dL, p = 0.0001) and both higher WBC and higher neutrophil counts than those without CVAs (p = 0.0001 and p = 0.01, respectively). Moreover, blood levels of albumin were significantly lower in KD patients with CVAs compared to those without (11/21, 52% versus 13/44, 30%, p = 0.02). Multiple logistic regression with correction for sex showed that serum vitamin D < 30 ng/mL, WBC count > 20.000/mm3, and age > 60 months at KD onset were the only independent factors statistically associated with CVAs. Conclusions: Hypovitaminosis D, WBC count over 20.000/mm3, and age above 5 years at KD onset emerged as independent factors statistically associated with the occurrence of CVAs.

Gut-Kidney-Heart: A Novel Trilogy.

The microbiota represents a key factor in determining health and disease. Its role in inflammation and immunological disorders is well known, but it is also involved in several complex conditions, ranging from neurological to psychiatric, from gastrointestinal to cardiovascular diseases. It has recently been hypothesized that the gut microbiota may act as an intermediary in the close interaction between kidneys and the cardiovascular system, leading to the conceptualization of the "gut-kidney-heart" axis. In this narrative review, we will discuss the impact of the gut microbiota on each system while also reviewing the available data regarding the axis itself. We will also describe the role of gut metabolites in this complex interplay, as well as potential therapeutical perspectives.

Hematological Complications in a COVID-19 Patient: A Case Report.

Hemophilia A is a hemorrhagic disorder caused by insufficient or inadequate coagulation factor VIII activity. Two different forms are described: congenital, hereditary X-linked, and acquired. Acquired hemophilia A (AHA) is a rare condition and it is defined by the production of autoantibodies neutralizing factor VIII, known as inhibitors. We report the case of a 72-year-old man with a clinical diagnosis of AHA after SARS-CoV-2 infection, which has been described in association with several hematological complications. SARS-CoV-2 infection could represent the immunological trigger for the development of autoantibodies. In our patient, SARS-CoV-2 infection preceded the hemorrhagic complications by 15 days. This lag time is in line with the other cases reported and compatible with the development of an intense immune response with autoantibody production. It is possible that since our patient was affected by type 1 diabetes mellitus, he was more prone to an immune system pathological response against self-antigens. A prompt, appropriate therapeutic intervention with activated recombinant factor VII administration and cyclophosphamide has led to rapid remission of clinical and laboratory findings.

What can autopsy say about COVID-19? A case series of 60 autopsies.

INTRODUCTION: Autopsies in SARS-CoV-2 infected cadavers are mainly performed to distinguish patients who died with SARS-CoV-2 infection from those who died of COVID-19. The aim of the current study is to assess the most frequent autopsy findings in patients who died of COVID-19 and to establish an association with clinical records. MATERIALS AND METHODS: 60 patients died between April 2020 and March 2021 after SARS-CoV-2 infection underwent a full autopsy performed at Fondazione Policlinico Universitario Agostino Gemelli IRCCS (Rome). Ante-mortem diagnosis of SARS-CoV-2 infection was microbiologically confirmed. RESULTS: 55 (92%) of cases had at least a comorbidity. At microscopic examination, 40 (67%) of the patients presented pulmonary intravascular coagulation with an inflammatory pattern. Pulmonary microangiopathy was a rare finding (n = 8; 13%). Myocardiosclerosis was the main heart finding (n = 44; 73%). Liver involvement with congestion and hypotrophy was found in 33 (55%) of cadavers. Renal tubular epithelial exfoliation (n = 12; 20%) and intravascular coagulation (n = 4; 7%) were frequent observations. During hospitalization 31% of patients (n = 19) developed acute kidney injury (AKI). CONCLUSIONS: Lungs and kidneys have been shown to play a pivotal role in COVID-19. The gradual worsening of renal function and AKI might be the result of the progressive collapse of cardiopulmonary system.

Current Evidence on Vaccinations in Pediatric and Adult Patients with Systemic Autoinflammatory Diseases.

Systemic autoinflammatory diseases (SAIDs) are defined by recurrent febrile attacks associated with protean manifestations involving joints, the gastrointestinal tract, skin, and the central nervous system, combined with elevated inflammatory markers, and are caused by a dysregulation of the innate immune system. From a clinical standpoint, the most known SAIDs are familial Mediterranean fever (FMF); cryopyrin-associated periodic syndrome (CAPS); mevalonate kinase deficiency (MKD); and periodic fever, aphthosis, pharyngitis, and adenitis (PFAPA) syndrome. Current guidelines recommend the regular sequential administration of vaccines for all individuals with SAIDs. However, these patients have a much lower vaccination coverage rates in 'real-world' epidemiological studies than the general population. The main purpose of this review was to evaluate the scientific evidence available on both the efficacy and safety of vaccines in patients with SAIDs. From this analysis, neither serious adverse effects nor poorer antibody responses have been observed after vaccination in patients with SAIDs on treatment with biologic agents. More specifically, no new-onset immune-mediated complications have been observed following immunizations. Post-vaccination acute flares were significantly less frequent in FMF patients treated with colchicine alone than in those treated with both colchicine and canakinumab. Conversely, a decreased risk of SARS-CoV-2 infection has been proved for patients with FMF after vaccination with the mRNA-based BNT162b2 vaccine. Canakinumab did not appear to affect the ability to produce antibodies against non-live vaccines in patients with CAPS, especially if administered with a time lag from the vaccination. On the other hand, our analysis has shown that immunization against Streptococcus pneumoniae, specifically with the pneumococcal polysaccharide vaccine, was associated with a higher incidence of adverse reactions in CAPS patients. In addition, disease flares might be elicited by vaccinations in children with MKD, though no adverse events have been noted despite concurrent treatment with either anakinra or canakinumab. PFAPA patients seem to be less responsive to measles, mumps, and rubella-vaccine, but have shown higher antibody response than healthy controls following vaccination against hepatitis A. In consideration of the clinical frailty of both children and adults with SAIDs, all vaccinations remain 'highly' recommended in this category of patients despite the paucity of data available.

Modified Mediterranean-Ketogenic Diet and Carboxytherapy as Personalized Therapeutic Strategies in Lipedema: A Pilot Study.

In recent years, the use of the ketogenic diet as a proper nutritional treatment for lipedema has been hypothesized in the literature. This is the first clinical study evaluating the ketogenic diet and carboxytherapy in lipedema patients. In the present study, it was decided to use a modified Mediterranean ketogenic diet (MMKD) in combination with carboxytherapy. Since lipedema is characterized by microangiopathy, local hypoxia, and increased subcutaneous adipose tissue (SAT) deposition, carboxytherapy could improve painful symptoms and skin tone. A total of 22 subjects were included in the data analysis, divided into three groups; 8 patients underwent MMKD combined with carboxytherapy sessions (KDCB group), 8 underwent MMKD nutritional treatment alone (KD group), and 6 patients underwent only carboxytherapy sessions (CB group), for a total of 10 weeks of treatment for all three groups. It was observed that the ketogenic diet effectively induced weight and fat mass loss, including in the limbs, areas considered unresponsive to diet therapy in lipedema patients. However, the best results were obtained from the combination of the ketogenic diet and carboxytherapy, which showed improvements in both body composition and skin texture and a reduction in pain, along with an improvement in sleep quality. It would be helpful to conduct a clinical trial on a larger scale and over a more extended period to observe the results in the long term as well.

Antioxidant-Enriched Diet on Oxidative Stress and Inflammation Gene Expression: A Randomized Controlled Trial.

The Mediterranean Diet (MedDiet) is associated with beneficial effects against chronic non-communicable diseases (CNCDs). In particular, the content of micronutrients leads to an improvement of the oxidative and inflammatory profiles. A randomized, parallel, controlled study, on 24 subjects, was conducted to evaluate if 2-week supplementation with a mixed apple and bergamot juice (MAB juice), had a positive impact on the body composition, the biochemical profile, and oxidative and inflammatory gene expression (Superoxide dismutase (SOD1), Peroxisome Proliferator-Activated Receptor γ (PPARγ), catalase (CAT), chemokine C-C motif ligand 5 (CCL5), Nuclear Factor Kappa B Subunit 1 (NFKB1), Vitamin D Receptor (VDR), and Macrophage Migration Inhibitory Factor (MIF)), respect to a MedDiet. Body composition evaluation analysis showed a gain in lean mass (p < 0.01). Moreover, a significant reduction in total cholesterol/HDL index (p < 0.01) was pointed out between the two groups. Gene expression analysis highlighted an increase in MIF (p ≤ 0.05), PPARγ (p < 0.001), SOD1 (p ≤ 0.05), and VDR (p ≤ 0.05) expressions when comparing MedDiet and MedDiet + MAB juice groups. These data based on the nutrigenomics approach demonstrated that supplementing 2 weeks of MAB juice to the MedDiet could contribute to a reduction in the risk of CNCDs.

Gut Microbiota, Inflammatory Bowel Disease, and Cancer: The Role of Guardians of Innate Immunity.

Inflammatory bowel diseases (IBDs) are characterized by a persistent low-grade inflammation that leads to an increased risk of colorectal cancer (CRC) development. Several factors are implicated in this pathogenetic pathway, such as innate and adaptive immunity, gut microbiota, environment, and xenobiotics. At the gut mucosa level, a complex interplay between the immune system and gut microbiota occurs; a disequilibrium between these two factors leads to an alteration in the gut permeability, called 'leaky gut'. Subsequently, an activation of several inflammatory pathways and an alteration of gut microbiota composition with a proliferation of pro-inflammatory bacteria, known as 'pathobionts', take place, leading to a further increase in inflammation. This narrative review provides an overview on the principal Pattern Recognition Receptors (PRRs), including Toll-like receptors (TLRs) and NOD-like receptors (NLRs), focusing on their recognition mechanisms, signaling pathways, and contributions to immune responses. We also report the genetic polymorphisms of TLRs and dysregulation of NLR signaling pathways that can influence immune regulation and contribute to the development and progression of inflammatory disease and cancer.

Factors Influencing Microbiota in Modulating Vaccine Immune Response: A Long Way to Go.

Vaccine immunogenicity still represents an unmet need in specific populations, such as people from developing countries and "edge populations". Both intrinsic and extrinsic factors, such as the environment, age, and dietary habits, influence cellular and humoral immune responses. The human microbiota represents a potential key to understanding how these factors impact the immune response to vaccination, with its modulation being a potential step to address vaccine immunogenicity. The aim of this narrative review is to explore the intricate interactions between the microbiota and the immune system in response to vaccines, highlighting the state of the art in gut microbiota modulation as a novel therapeutic approach to enhancing vaccine immunogenicity and laying the foundation for future, more solid data for its translation to the clinical practice.