Zonulin, a regulator of epithelial and endothelial barrier functions, and its involvement in chronic inflammatory diseases

Plasma proteomic profiles of patients with HIV infection and coinfection with hepatitis B/C virus undergoing anti‑retroviral therapy

Chronic liver disease is becoming a leading cause of illness and mortality in patients living with human immunodeficiency virus (HIV; PLWH) undergoing suppressive anti-retroviral therapy. Its primary etiology is coinfection with hepatitis B and C virus (HBV and HCV, respectively). Chronic liver inflammation and fibrosis can potentially lead to the development of hepatocellular carcinoma (HCC). Therefore, monitoring of the disease progression in PLWH is required. The present study aimed to explore plasma protein profiles of PLWH and those coinfected with HBV and HCV using shotgun proteomics. HIV-monoinfected, HIV/HBV-coinfected, HIV/HCV-coinfected and uninfected control individuals were recruited. Patients in the three virus-infected groups had significantly higher levels of liver fibrosis indices (fibrosis-4 score and aspartate aminotransferase to platelet ratio index) compared with the control group. Liquid chromatography-tandem mass spectrometry analysis of plasma samples identified 1,074 proteins that were differentially expressed, where subsequent partial least squares-discriminant analysis model demonstrated clear clustering of proteomes from the four sample groups; 18 proteins that were significantly differentially expressed. Heatmap analysis identified two main groups of proteins, six proteins being upregulated only in the HIV/HBV-coinfection group and 10 proteins downregulated in all three virally infected groups. STITCH 5.0 analysis predicted an interaction network containing two identified proteins in the latter group, specifically ubiquitin interaction motif-containing 1 (UIMC1) and haptoglobin (HP), which are part of the profibrogenic TGF-1β/SMAD, inflammatory TNF and tumor suppressor BRCA1 pathways. Expression levels of UIMC1 and HP were significantly lower in HIV-infected groups compared with those in uninfected controls. Altogether, these proteomics data provide protein expression profiles potentially associated with HIV infection and coinfection with HBV/HCV, which may be applied to predict progression to advanced liver disease or HCC in PLWH.

Replacement of the massive amino acid losses induced by hemodialysis: A new treatment option proposal for a largely underestimated issue

BACKGROUND

A series of interesting literature reports acknowledges the notable loss of essential and non-essential amino acids (EAAs and NEAAs) during hemodialysis sessions. These losses may exceed 800 g/year, thus contributing towards accelerating the onset of malnutrition in hemodialysis patients (HD).

OBJECTIVE

A novel tailored amino acid formula for oral administration was developed to replace total amounts of each individual amino acid lost during dialysis diffusive/convective HD strategies, monitoring the effects produced on nutritional and hematological status.

METHODS

A three-month randomized double-blind study was conducted on 30 subjects over the age of 70 years extrapolated from a total population of 86 hemodialysis patients. The 30 patients were randomly assigned to two groups: a treatment group of 15 HD patients (TG) to whom a novel mixture containing 5.4 g of AAs was administered solely on interdialytic days, and a control group of 15 HD patients (CG) who received no amino acid supplementation. The AAs mixture was administered post-dialysis at an extended interval from the end of solute and compartmental rebound to replace AA losses and optimize their role in protein anabolism.

RESULTS

The results obtained highlighted a significant improvement in protein intake g/kg/day (Protein Catabolic Rate, p = 0.014), and increased IgG (p = 0.008) and C3 serum levels (p = 0.003) in the TG group alone. Fat mass losses were initially confirmed by means of bioelectrical impedance analysis (BIA) (p = 0.011) and plicometry (p < 0.001) in the CG group alone, although the main objective was to preserve nutritional status and, particularly, muscle mass. The study was extended to investigate the effects produced on anemia, yielding evidence of continued positive effects three months after the end of the study in the TG group alone based on an increase in Hb levels from 11.2 ± 0.6 to 12.1 ± 0.6 (p = 0.004) associated with a reduced demand for erythropoietin i.v. from 12928 ± 9033 to 9286 ± 5398 U.I/week (p = 0.012) and iron i.v. from 75.9 ± 55 to 71.4 ± 33.4 mg/week (p = 0.045).

CONCLUSIONS

The results obtained following oral administration of this novel tailored AA replacement mixture aimed at reinstating the high AA losses produced during hemodialysis suggest the mixture should be prescribed as a standard procedure to all HD patients.

Intestinal permeability disturbances: causes, diseases and therapy

Nowadays, a pathological increase in the permeability of the intestinal barrier (the so-called leaky gut) is increasingly being diagnosed. This condition can be caused by various factors, mainly from the external environment. Damage to the intestinal barrier entails a number of adverse phenomena: dysbiosis, translocation of microorganisms deep into the intestinal tissue, immune response, development of chronic inflammation. These phenomena can ultimately lead to a vicious cycle that promotes the development of inflammation and further damage to the barrier. Activated immune cells in mucosal tissues with broken barriers can migrate to other organs and negatively affect their functioning. Damaged intestinal barrier can facilitate the development of local diseases such as irritable bowel disease, inflammatory bowel disease or celiac disease, but also the development of systemic inflammatory diseases such as rheumatoid arthritis, ankylosing spondylitis, hepatitis, and lupus erythematosus, neurodegenerative or psychiatric conditions, or metabolic diseases such as diabetes or obesity. However, it must be emphasized that the causal links between a leaky gut barrier and the onset of certain diseases often remain unclear and require in-depth research. In light of recent research, it becomes crucial to prevent damage to the intestinal barrier, as well as to develop therapies for the barrier when it is damaged. This paper presents the current state of knowledge on the causes, health consequences and attempts to treat excessive permeability of the intestinal barrier.

The Hidden Relationship between Intestinal Microbiota and Immunological Modifications in Preeclampsia Pathogenesis

Preeclampsia is a multifactorial gestational syndrome characterized by increased blood pressure during pregnancy associated with multiorgan involvement. The impact of this disease on maternal and neonatal health is significant, as it can lead to various fetal comorbidities and contribute to the development of maternal comorbidities later in life. Consistent evidence has shown that the microbiota acts as a regulator of the immune system, and it may, therefore, influence the development of preeclampsia by modulating immune factors. This narrative review aims to investigate the role of the immune system in the pathogenesis of preeclampsia and to summarize the most recent literature on the possible link between preeclampsia and alterations in the intestinal microbiota. To this end, we conducted a literature search, aiming to perform a narrative review, on PubMed and Embase from January 1990 to March 2024, focusing on the latest studies that highlight the main differences in microbial composition between patients with and without preeclampsia, as well as the effects of microbial metabolites on the immune system. From the review of 28 studies assessing the intestinal microbiota in preeclamptic women, preeclampsia could be associated with a state of dysbiosis. Moreover, these patients showed higher plasmatic levels of endotoxin, pro-inflammatory cytokines, and T helper 17 cells; however, the findings on specific microbes and metabolites that could cause immune imbalances in preeclampsia are still preliminary.

Faecal intestinal permeability and intestinal inflammatory markers in older adults with age-related disorders: A systematic review and meta-analysis

This systematic review and meta-analysis appraised previous findings to uncover potential faecal intestinal permeability and intestinal inflammatory markers in older adults. A comprehensive literature search led to the identification of ten eligible studies with findings of potential faecal intestinal permeability (zonulin and alpha-1-antitrypsin) and intestinal inflammatory markers [calprotectin, lactoferrin and neutrophil gelatinase-associated lipocalin (NGAL)]. Most of the cases (n > 2) [Parkinson's disease (PD) and Alzheimer's disease (AD)] exhibited higher faecal alpha-1-antitrypsin, zonulin and calprotectin levels. The present meta-analysis confirmed significantly higher faecal alpha-1-antitrypsin in older persons with PD compared to non-PD [MD = 22.92 mg/dL; 95 % CI = 14.02-31.81, p < 0.00001; I2 = 0 % (p = 0.73)]. There was, however, no significant difference in faecal zonulin between PD and non-PD individuals [MD = 26.88 ng/mL; 95 % CI = -29.26-83.01, p = 0.35; I2 = 94 % (p < 0.0001)]. Meanwhile, faecal calprotectin was higher in older adults with GI symptoms, multiple system atrophy (MSA) or PD than the healthy controls [MD = 9.51 μg/g; 95 % CI = 0.07-18.95, p = 0.05; I2 = 84 % (p < 0.00001)]. Altogether, faecal calprotectin appears to be a potential intestinal inflammatory marker whereas previous findings on faecal alpha-1-antitrypsin as an intestinal permeability marker remain limited and require further validation.

The blood-brain barrier in bipolar disorders: A systematic review

BACKGROUND

Bipolar disorders (BD) are chronic, debilitating disorders. The blood-brain barrier (BBB) has been increasingly investigated in BD. This systematic review aimed to assess the available evidence on the relationship between BD and markers of BBB dysfunction.

METHODS

A systematic search in PubMed, Embase, PsycINFO, CINAHL and Web of Science was run where the primary outcomes were BBB markers such as S100B, albumin ratio, matrix metalloproteinase (MMP), cell adhesion molecule (CAM), and tight junction proteins. Techniques included blood, cerebrospinal fluid (CSF), post-mortem, genetic and imaging methods in BD compared to healthy controls.

RESULTS

55 studies were identified, 38 of which found an association between BD and markers of BBB dysfunction. 16/29 studies found increased blood/CSF albumin ratio, S100B, CAMs or MMP levels in BD participants compared to controls. 5/19 post-mortem studies found increased levels of chondroitin sulphate proteoglycans, intercellular CAM, neurexin or claudin-5 mRNA in distinct locations throughout the brain in BD compared to controls. One imaging study identified extensive BBB leakage in 30 % of BD participants, compared to 0 % in controls.

LIMITATIONS

The diversity in methodologies used in the included studies makes direct comparison of results challenging. Furthermore, imaging methods are the gold standard, but only one study used them. Other markers are only indicative of BBB permeability.

CONCLUSIONS

This review suggests an association between BD and BBB dysfunction. Further research is needed to provide definite answers considering the existing literature's limitations, and to clarify whether this association provides a pathogenic mechanism, or is an epiphenomenon of BD.

Dietary supplementation with a blend composed of carvacrol, tannic acid derived from Castanea sativa and Glycyrrhiza glabra, and glycerides of medium chain fatty acids for weanling piglets raised in commercial farm

This study aimed to evaluate the dietary administration of a blend composed of carvacrol, tannic acid derived from Castanea sativa mill and Glycyrrhiza glabra, medium chain fatty acids (MCFAs) glycerides for weanling piglets. An in vitro digestion followed by total phenolic content (TPC) and total antioxidant activity (TAC) assessment was performed before the in vivo application. At weaning, a total of 210 piglets were randomly allocated to two experimental treatments (7 replicates/15 piglets for each replicate). Control group (CTR) was fed a standard basal diet while the treated group (T) was fed the basal diet mixed with 1.500 mg/kg of blend. After in vitro digestion, TPC and TAC evidenced peaks at the end of oral and gastric phases in comparison to the intestinal one in line with the high content of phenolic compound (P < 0.05). Treatment conditioned body weight and average daily gain (P < 0.05), fecal score on 6, 7, and 8 d after weaning (P < 0.05). At 35d, the T group showed a decrease in salivary cortisol compared to CTR (P < 0.05). Duodenum and jejunum sections of T piglets revealed higher villi (P < 0.05), deeper crypts (P < 0.01), and increased V/C ratio (P < 0.01). CTR showed a higher expression of duodenal Occludin (P < 0.05). Jejunal E-cadherin and Occludin were more expressed in T jejunum sections (P < 0.05). Twelve differentially abundant genera were identified in T group caecal samples. Potentially harmful Clostridium sensu stricto 13 was reduced by the treatment (P < 0.05). In conclusion, the tested blend positively affected salivary stress markers and the gut health of weaned piglets.

Repurposing metformin as adjuvant therapy in patients with ulcerative colitis treated with mesalamine: A randomized controlled double-blinded study

BACKGROUND

Ulcerative colitis (UC) is a type of inflammatory bowel disease associated with persistent inflammation. Animal studies proved the efficacy of metformin in UC.

AIM

To investigate the potential role of metformin and its protective pathways in patients with UC.

METHODS

This is a randomized, controlled, and double-blinded clinical trial that included 60 participants with mild to moderate UC and was divided randomly into two groups (n = 30). For 6 months, the mesalamine group received 1 g of mesalamine three times daily (t.i.d.). For six months, the metformin group received mesalamine 1 g t.i.d. and metformin 500 mg twice daily. A gastroenterologist evaluated patients at baseline and 6 months after starting the treatment in order to measure serum levels of zonulin, sphingosine 1 phosphate (S1P), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Biopsies from the colon were used to measure gene expression of zonula occuldin-1 (ZO-1), signal transducer and activator of factor-3 (STAT-3), and intracellular adhesion molecule-1 (ICAM-1). The numeric pain rating scale (NRS) and partial Mayo score were also assessed for each patient.

RESULTS

When compared to the mesalamine group, the metformin group demonstrated a statistical decrease in serum IL-6, zonulin, TNF-α, SIP, gene expression of ICAM-1 and STAT-3, and a significant increase in colonic ZO-1 when compared to the mesalamine group. The metformin group also showed a significant decrease in NRS and partial Mayo score index in comparison with the mesalamine group.

CONCLUSION

Metformin may be a promising additional therapy for UC patients. Trial registration identifier: NCT05553704.

The Kynurenine Pathway in Gut Permeability and Inflammation

The gut-brain axis (GBA) is a crucial communication network linking the gastrointestinal (GI) tract and the central nervous system (CNS). The gut microbiota significantly influences metabolic, immune, and neural functions by generating a diverse array of bioactive compounds that modulate brain function and maintain homeostasis. A pivotal mechanism in this communication is the kynurenine pathway, which metabolises tryptophan into various derivatives, including neuroactive and neurotoxic compounds. Alterations in gut microbiota composition can increase gut permeability, triggering inflammation and neuroinflammation, and contributing to neuropsychiatric disorders. This review elucidates the mechanisms by which changes in gut permeability may lead to systemic inflammation and neuroinflammation, with a focus on the kynurenine pathway. We explore how probiotics can modulate the kynurenine pathway and reduce neuroinflammation, highlighting their potential as therapeutic interventions for neuropsychiatric disorders. The review integrates experimental data, discusses the balance between neurotoxic and neuroprotective kynurenine metabolites, and examines the role of probiotics in regulating inflammation, cognitive development, and gut-brain axis functions. The insights provided aim to guide future research and therapeutic strategies for mitigating GI complaints and their neurological consequences.

Can Faecal Zonulin and Calprotectin Levels Be Used in the Diagnosis and Follow-Up in Infants with Milk Protein-Induced Allergic Proctocolitis?

OBJECTIVE

The aim of our study was to investigate whether a 1-month-long milk-free diet results in a reduction in faecal calprotectin (FC) and faecal-zonulin-related proteins (FZRP) in children with milk-protein-induced allergic proctocolitis (MPIAP).

MATERIALS AND METHODS

This is a single-centre, prospective, observational cohort study involving 86 infants with MPIAP, aged 1-3 months, and 30 healthy controls of the same age. The FC and FZRP were marked using the ELISA method (IDK® Calprotectin or Zonulin ELISA Kit, Immunodiagnostik AG, Bensheim, Germany). The diagnosis of MPIAP was confirmed with an open milk challenge test.

RESULTS

FFC and FZRP proved useful in evaluating MPIAP treatment with a milk-free diet, and the resolution of allergic symptoms and a significant (p = 0.0000) decrease in the concentrations of both biomarkers were observed after 4 weeks on the diet. The FC and FZRP concentrations were still higher than in the control group. A high variability of FC concentrations was found in all the study groups. An important limitation is the phenomenon of FZRP not being produced in all individuals, affecting one in five infants.

CONCLUSIONS

FC and FZRP can be used to monitor the resolution of colitis in infants with MPIAP treated with a milk-free diet, indicating a slower resolution of allergic inflammation than of allergic symptoms. The diagnosis of MPIAP on the basis of FC concentrations is subject to considerable error, due to the high individual variability of this indicator. FZRP is a better parameter, but this needs further research, as these are the first determinations in infants with MPIAP.

The Molecular Signature Related to Local Inflammatory and Immune Response in Canine Cutaneous Hypersensitivity Reactions: A Preliminary Study

Cutaneous hypersensitivity reactions (CHRs) are complex inflammatory skin disorders that affect humans and dogs. This study examined the inflammatory and immune responses leading to skin damage, inflammation, and irritation by investigating gene expression through quantitative PCR (qPCR) and protein localization through the immunohistochemistry (IHC) of specific receptors and molecules involved in CHRs. Formalin-fixed paraffin-embedded (FFPE) samples from canine CHR skin (n = 20) and healthy dog skin (n = 3) were analyzed for expression levels of eight genes, including members of the pattern recognition receptor (PRR) family, CD209 and CLEC4G, the Regakine-1-like chemokine, and acute phase proteins (APPs), LBP-like and Hp-like genes. Additionally, we examined the local involvement of IL-6, Janus Kinase 1 (JAK1), and the signal transducer activator of transcription 3 (STAT3) in the CHR cases. The study demonstrated statistically significant increases in the expression levels of CD209, Hp-like (p < 0.01), LBP-like, Regakine-1-like, and CLEC4G (p < 0.05) genes in CHRs compared to healthy controls. Conversely, IL-6, JAK1, and STAT3 showed no significant difference between the two groups (p > 0.05). Protein analysis revealed JAK1 and STAT3 expression in CHR hyperplastic epithelial cells, dermal fibroblasts, and endothelial cells of small capillaries, indicating a possible involvement in the JAK/STAT pathway in local inflammatory response regulation. Our findings suggest that the skin plays a role in the development of CHRs.

Cardiovascular Risk in Patients with Inflammatory Bowel Diseases-The Role of Endothelial Dysfunction

Inflammatory bowel disease (IBD) is associated with an increased risk of cardiovascular disease (CVD). Cardiovascular pathology in people with IBD has not been well studied to date, and a direct link between cardiovascular events and IBD has not been established. The mechanisms underlying this association include the parallel and dynamic interaction of inflammation, modulation of the composition of the gut microbiota, endothelial dysfunction, thrombogenicity, and increased endothelial and epithelial permeability. Endothelial dysfunction is a common aspect of the pathogenesis of IBD and atherosclerotic CVD and can be considered one of the most important factors leading to the development and progression of cardiovascular pathology in patients with IBD. The purpose of this literature review is to describe the mechanisms underlying the development of endothelial dysfunction and disorders of the structure and function of the gut-vascular barrier in the pathogenesis of the cardiovascular manifestation of IBD.

Intestinal Dysbiosis, Tight Junction Proteins, and Inflammation in Rheumatoid Arthritis Patients: A Cross-Sectional Study

Recent studies point to intestinal permeability as an important factor in the establishment and development of rheumatoid arthritis (RA). Tight junctions (TJs) play a major role in intestinal homeostasis. The alteration of this homeostasis is related to RA. Furthermore, RA patients present dysbiosis and a lower microbiota diversity compared to healthy individuals. A cross-sectional study including RA patients and sex- and age-matched healthy controls was performed. The quantification of TJ proteins was carried out by ELISA. Gut microbiota was evaluated by NGS platform Ion Torrent S. The inflammatory variables included were DAS28, CRP, inflammatory cytokines (IL-6, IL-1, TNF-α) and oxidised LDL. Claudin-1 levels showed significant differences between groups. Results evidenced a correlation between claudin-1 values and age (r: -0.293; p < 0.05), IL6 (r: -0.290; p < 0.05) and CRP (r: -0.327; p < 0.05), and between zonulin values and both age (r: 0.267; p < 0.05) and TNFα (r: 0.266; p < 0.05). Moreover, claudin-1 and CRP levels are related in RA patients (β: -0.619; p: 0.045), and in patients with high inflammatory activity, the abundance of the genus Veillonella is positively associated with claudin-1 levels (β: 39.000; p: 0.004).

Assessment of Serum Zonulin Levels in Individuals Diagnosed With Chronic Spontaneous Urticaria

BACKGROUND

There have been reports indicating a correlation between heightened intestinal permeability and many autoimmune and chronic inflammatory disorders. The involvement of autoimmunity is now recognized as a significant factor in the development of chronic spontaneous urticaria (CSU). Zonulin is an important biomarker that regulates tight junction permeability within cells in the gastrointestinal tract, hence facilitating intestinal permeability.

OBJECTIVE

To evaluate the correlation of CSU with intestinal permeability by measuring the serum levels of zonulin in patients diagnosed with CSU.

METHODS

The study included 60 patients diagnosed with CSU and 64 age- and sex-matched healthy individuals as controls. Levels of serum zonulin were determined using the ELISA method.

RESULTS

Although the serum zonulin value of the patients was higher compared to the controls, the difference did not reach a significant level (24.65±8.49 ng/ml vs. 21.03±7.36 ng/ml, p=0.077). The serum zonulin level had a significant correlation with the urticaria activity score in the CSU group (p=0.013). The results of the current study revealed that serum zonulin values significantly differed between patients with CSU and healthy controls.

CONCLUSION

This study is important in terms of being the first to investigate the serum zonulin levels in CSU. However, there is a need for further studies with larger patient groups.

Intestinal permeability in human cardiovascular diseases: a systematic review and meta-analysis

Background

There is a link between cardiovascular diseases and intestinal permeability, but it is not clear. This review aimed to elucidate intestinal permeability in cardiovascular diseases by meta-analysis.

Methods

Multidisciplinary electronic databases were searched from the database creation to April 2023. All included studies were assessed for risk of bias according to the Joanna Briggs Institute Critical Appraisal Checklist. The heterogeneity of each study was estimated using the I2 statistic, and the data were analyzed using Review Manager 5.3 and Stata 16.0.

Results

In total, studies in 13 pieces of literature were included in the quantitative meta-analysis. These studies were conducted among 1,321 subjects mostly older than 48. Patients had higher levels of intestinal permeability markers (lipopolysaccharide, d-lactate, zonulin, serum diamine oxidase, lipopolysaccharide-binding protein, intestinal fatty acid binding protein, and melibiose/rhamnose) than controls (standard mean difference SMD = 1.50; 95% CI = 1.31-1.88; p < 0.00001). Similarly, lipopolysaccharide levels were higher in patients than in controls (SMD = 1.61; 95% CI = 1.02-2.21; p < 0.00001); d-lactate levels were higher in patients than in controls (SMD = 1.16; 95% CI = 0.23-2.08; p = 0.01); zonulin levels were higher in patients than in controls (SMD = 1.74; 95% CI = 1.45-2.03; p < 0.00001); serum diamine oxidase levels were higher in patients than in controls (SMD = 2.51; 95% CI = 0.29-4.73; p = 0.03).

Conclusion

The results of the meta-analysis verified that the intestinal barrier was damaged and intestinal permeability was increased in patients with cardiovascular diseases. These markers may become a means of the diagnosis and treatment of cardiovascular diseases.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=414296, identifier CRD42023414296.

Microscopic Colitis and Celiac Disease: Sharing More than a Diagnostic Overlap

Microscopic colitis (MC) is an emergent group of chronic inflammatory diseases of the colon, and celiac disease (CD) is a chronic gluten-induced immune-mediated enteropathy affecting the small bowel. We performed a narrative review to provide an overview regarding the relationship between both disorders, analyzing the most recent studies published at the epidemiological, clinical and pathophysiological levels. In fact, MC and CD are concomitantly prevalent in approximately 6% of the cases, mainly in the subset of refractory patients. Thus, physicians should screen refractory patients with CD against MC and vice versa. Both disorders share more than a simple epidemiological association, being multifactorial diseases involving innate and adaptive immune responses to known or unknown luminal factors based on a rather common genetic ground. Moreover, autoimmunity is a shared characteristic between the patients with MC and those with CD, with autoimmunity in the latter being quite well-established. Furthermore, CD and MC share some common clinical symptoms and risk factors and overlap with other gastrointestinal diseases, but some differences exist between both disorders. More studies are therefore needed to better understand the complex mechanisms involving the common pathogenetic ground contributing to the CD and MC epidemiological association.

The Impact of Surgical Bowel Preparation on the Microbiome in Colon and Rectal Surgery

Preoperative bowel preparation, through iterations over time, has evolved with the goal of optimizing surgical outcomes after colon and rectal surgery. Although bowel preparation is commonplace in current practice, its precise mechanism of action, particularly its effect on the human gut microbiome, has yet to be fully elucidated. Absent intervention, the gut microbiota is largely stable, yet reacts to dietary influences, tissue injury, and microbiota-specific byproducts of metabolism. The routine use of oral antibiotics and mechanical bowel preparation prior to intestinal surgical procedures may have detrimental effects previously thought to be negligible. Recent evidence highlights the sensitivity of gut microbiota to antibiotics, bowel preparation, and surgery; however, there is a lack of knowledge regarding specific causal pathways that could lead to therapeutic interventions. As our understanding of the complex interactions between the human host and gut microbiota grows, we can explore the role of bowel preparation in specific microbiome alterations to refine perioperative care and improve outcomes. In this review, we outline the current fund of information regarding the impact of surgical bowel preparation and its components on the adult gut microbiome. We also emphasize key questions pertinent to future microbiome research and their implications for patients undergoing colorectal surgery.

Improved Gut Health May Be a Potential Therapeutic Approach for Managing Prediabetes: A Literature Review

Given the growing global threat and rising prevalence of type 2 diabetes mellitus (T2DM), addressing this metabolic disease is imperative. T2DM is preceded by prediabetes (PD), an intermediate hyperglycaemia that goes unnoticed for years in patients. Several studies have shown that gut microbial diversity and glucose homeostasis in PD or T2DM patients are affected. Therefore, this review aims to synthesize the existing literature to elucidate the association between high-calorie diets, intestinal permeability and their correlation with PD or T2DM. Moreover, it discusses the beneficial effects of different dietary interventions on improving gut health and glucose metabolism. The primary factor contributing to complications seen in PD or T2DM patients is the chronic consumption of high-calorie diets, which alters the gut microbial composition and increases the translocation of toxic substances from the intestinal lumen into the bloodstream. This causes an increase in inflammatory response that further impairs glucose regulation. Several dietary approaches or interventions have been implemented. However, only a few are currently in use and have shown promising results in improving beneficial microbiomes and glucose metabolism. Therefore, additional well-designed studies are still necessary to thoroughly investigate whether improving gut health using other types of dietary interventions can potentially manage or reverse PD, thereby preventing the onset of T2DM.

Western diet components that increase intestinal permeability with implications on health

Intestinal permeability is a physiological property that allows necessary molecules to enter the organism. This property is regulated by tight junction proteins located between intestinal epithelial cells. However, various factors can increase intestinal permeability (IIP), including diet. Specific components in the Western diet (WD), such as monosaccharides, fat, gluten, salt, alcohol, and additives, can affect the tight junctions between enterocytes, leading to increased permeability. This review explains how these components promote IIP and outlines their potential implications for health. In addition, we describe how a reduction in WD consumption may help improve dietary treatment of diseases associated with IIP. Research has shown that some of these components can cause changes in the gut microbiota, leading to dysbiosis, which can promote greater intestinal permeability and displacement of endotoxins into the bloodstream. These endotoxins include lipopolysaccharides derived from gram-negative bacteria, and their presence has been associated with various diseases, such as autoimmune, neurological, and metabolic diseases like diabetes and cardiovascular disease. Therefore, nutrition professionals should promote the reduction of WD consumption and consider the inclusion of healthy diet components as part of the nutritional treatment for diseases associated with increased intestinal permeability.

The Gut and the Translocated Microbiomes in HIV Infection: Current Concepts and Future Avenues

It is widely acknowledged that HIV infection results in disruption of the gut's mucosal integrity partly due a profound loss of gastrointestinal CD4+ T cells that are targets of the virus. In addition, systemic inflammation and immune activation that drive disease pathogenesis are reduced but not normalized by antiretroviral therapy (ART). It has long been postulated that through the process of microbial translocation, the gut microbiome acts as a key driver of systemic inflammation and immune recovery in HIV infection. As such, many studies have aimed at characterizing the gut microbiota in order to unravel its influence in people with HIV and have reported an association between various bacterial taxa and inflammation. This review assesses both contra-dictory and consistent findings among several studies in order to clarify the overall mechanisms by which the gut microbiota in adults may influence immune recovery in HIV infection. Independently of the gut microbiome, observations made from analysis of microbial products in the blood provide direct insight into how the translocated microbiome may drive immune recovery. To help better understand strengths and limitations of the findings reported, this review also highlights the numerous factors that can influence microbiome studies, be they experimental methodologies, and host-intrinsic or host-extrinsic factors. Altogether, a fuller understanding of the interplay between the gut microbiome and immunity in HIV infection may contribute to preventive and therapeutic approaches.

Amyloid, Crohn's disease, and Alzheimer's disease - are they linked?

Crohn's disease (CD) is a chronic inflammatory disease that most frequently affects part of the distal ileum, but it may affect any part of the gastrointestinal tract. CD may also be related to systemic inflammation and extraintestinal manifestations. Alzheimer's disease (AD) is the most common neurodegenerative disease, gradually worsening behavioral and cognitive functions. Despite the meaningful progress, both diseases are still incurable and have a not fully explained, heterogeneous pathomechanism that includes immunological, microbiological, genetic, and environmental factors. Recently, emerging evidence indicates that chronic inflammatory condition corresponds to an increased risk of neurodegenerative diseases, and intestinal inflammation, including CD, increases the risk of AD. Even though it is now known that CD increases the risk of AD, the exact pathways connecting these two seemingly unrelated diseases remain still unclear. One of the key postulates is the gut-brain axis. There is increasing evidence that the gut microbiota with its proteins, DNA, and metabolites influence several processes related to the etiology of AD, including β-amyloid abnormality, Tau phosphorylation, and neuroinflammation. Considering the role of microbiota in both CD and AD pathology, in this review, we want to shed light on bacterial amyloids and their potential to influence cerebral amyloid aggregation and neuroinflammation and provide an overview of the current literature on amyloids as a potential linker between AD and CD.

Unveiling the Novel Benefits of Co-Administering Butyrate and Active Vitamin D3 in Mice Subjected to Chemotherapy-Induced Gut-Derived Pseudomonas aeruginosa Sepsis

Cancer patients face increased susceptibility to invasive infections, primarily due to ulcerative lesions on mucosal surfaces and immune suppression resulting from chemotherapy. Pseudomonas aeruginosa (P. aeruginosa) bacteremia is notorious for its rapid progression into fatal sepsis, posing a significant threat to cancer patients, particularly those experiencing chemotherapy-induced neutropenia. This bacterial infection contributes significantly to morbidity and mortality rates among such individuals. Our latest report showed the mutually beneficial effects of postbiotic butyrate on 1,25-dihydroxyvitamin D3 (1,25D3)-controlled innate immunity during Salmonella colitis. Hence, we investigated the impact of butyrate and 1,25D3 on chemotherapy-induced gut-derived P. aeruginosa sepsis in mice. The chemotherapy-induced gut-derived P. aeruginosa sepsis model was established through oral administration of 1 × 107 CFU of the P. aeruginosa wild-type strain PAO1 in C57BL/6 mice undergoing chemotherapy. Throughout the infection process, mice were orally administered butyrate and/or 1,25D3. Our observations revealed that the combined action of butyrate and 1,25D3 led to a reduction in the severity of colitis and the invasion of P. aeruginosa into the liver and spleen of the mice. This reduction was attributed to an enhancement in the expression of defensive cytokines and antimicrobial peptides within the cecum, coupled with decreased levels of zonulin and claudin-2 proteins in the mucosal lining. These effects were notably more pronounced when compared to treatments administered individually. This study unveils a promising alternative therapy that involves combining postbiotics and 1,25D3 for treating chemotherapy-induced gut-derived P. aeruginosa sepsis.

Intestinal permeability correlates with disease activity and DNA methylation changes in lupus patients

OBJECTIVE

Systemic lupus erythematosus (SLE or lupus) is a chronic autoimmune disease that can involve various organ systems. Several studies have suggested that increased intestinal permeability may play a role in the pathogenesis of lupus. The aim of this study was to elucidate the relationship between intestinal permeability, disease activity, and epigenetic changes in lupus patients.

METHODS

A total of 25 female lupus patients were included in this study. Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores were used as indicator of disease activity. Plasma zonulin levels were measured, using an ELISA, as a marker of intestinal permeability. Genome-wide DNA methylation patterns were assessed in neutrophils for 19 of the lupus patients using the Infinium MethylationEPIC array. Linear regression and Pearson's correlation were used to evaluate the correlation between zonulin concentrations and SLEDAI scores. The relationship between DNA methylation levels and zonulin concentrations was assessed using beta regression, linear regression, and Pearson's correlation, adjusting for age and race.

RESULTS

Intestinal permeability positively correlated with disease activity in lupus patients (p-value = 7.60 × 10-3, r = 0.53). DNA methylation levels in 926 CpG sites significantly correlated with intestinal permeability. The highest correlation was identified in LRIG1 (cg14159396, FDR-adjusted p-value = 1.35 × 10-12, adjusted r2 = 0.92), which plays a role in intestinal homeostasis. Gene Ontologies related to cell-cell adhesion were enriched among the genes that were hypomethylated with increased intestinal permeability in lupus.

CONCLUSION

Our data suggest a correlation between increased intestinal permeability and disease activity in lupus patients. Further, increased intestinal permeability might be associated with epigenetic changes that could play a role in the pathogenesis of lupus.

Exploring the Associations of Inflammatory and Oxidative Stress Biomarkers with Pancreatic Diseases: An Observational and Mendelian Randomisation Study

Identifying biomarkers linked to pancreatic ductal adenocarcinoma (PDAC) and chronic pancreatitis (CP) is crucial for early detection, treatment, and prevention. Methods: Association analyses of 10 serological biomarkers involved in cell signalling (IFN-γ, IL-6, IL-8, IL-10), oxidative stress (superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzyme activities, total glutathione (GSH), malondialdehyde (MDA) levels), and intestinal permeability proteins (zonulin, I-FABP2) were conducted across PDAC (n = 12), CP (n = 21) and control subjects (n = 23). A Mendelian randomisation (MR) approach was used to assess causality of the identified significant associations in two large genetic cohorts (FinnGen and UK Biobank). Results: Observational results showed a downregulation of SOD and GPx antioxidant enzyme activities in PDAC and CP patients, respectively, and higher MDA levels in CP patients. Logistic regression models revealed significant associations between CP and SOD activity (OR = 0.21, 95% CI [0.05, 0.89], per SD), GPx activity (OR = 0.28, 95% CI [0.10, 0.79], per SD), and MDA levels (OR = 2.05, 95% CI [1.36, 3.08], per SD). MR analyses, however, did not support causality. Conclusions: These findings would not support oxidative stress-related biomarkers as potential targets for pancreatic diseases prevention. Yet, further research is encouraged to assess their viability as non-invasive tools for early diagnosis, particularly in pre-diagnostic CP populations.

Intestinal Barrier Dysfunction and Gut Microbiota in Non-Alcoholic Fatty Liver Disease: Assessment, Mechanisms, and Therapeutic Considerations

Non-alcoholic fatty liver disease (NAFLD) is a type of metabolic stress liver injury closely related to insulin resistance (IR) and genetic susceptibility without alcohol consumption, which encompasses a spectrum of liver disorders ranging from simple hepatic lipid accumulation, known as steatosis, to the more severe form of steatohepatitis (NASH). NASH can progress to cirrhosis and hepatocellular carcinoma (HCC), posing significant health risks. As a multisystem disease, NAFLD is closely associated with systemic insulin resistance, central obesity, and metabolic disorders, which contribute to its pathogenesis and the development of extrahepatic complications, such as cardiovascular disease (CVD), type 2 diabetes mellitus, chronic kidney disease, and certain extrahepatic cancers. Recent evidence highlights the indispensable roles of intestinal barrier dysfunction and gut microbiota in the onset and progression of NAFLD/NASH. This review provides a comprehensive insight into the role of intestinal barrier dysfunction and gut microbiota in NAFLD, including intestinal barrier function and assessment, inflammatory factors, TLR4 signaling, and the gut-liver axis. Finally, we conclude with a discussion on the potential therapeutic strategies targeting gut permeability and gut microbiota in individuals with NAFLD/NASH, such as interventions with medications/probiotics, fecal transplantation (FMT), and modifications in lifestyle, including exercise and diet.

Immunosenescence, gut dysbiosis, and chronic kidney disease: Interplay and implications for clinical management

Immunosenescence refers to the immune system changes observed in individuals over 50 years old, characterized by diminished immune response and chronic inflammation. Recent investigations have highlighted similar immune alterations in patients with reduced kidney function. The immune system and kidney function have been found to be closely interconnected. Studies have shown that as kidney function declines, both innate and adaptive immunity are affected. Chronic kidney disease (CKD) patients exhibit decreased levels of naive and regular T cells, as well as naive and memory B cells, while memory T cell counts increase. Furthermore, research suggests that CKD and end-stage kidney disease (ESKD) patients experience early thymic dysfunction and heightened homeostatic proliferation of naive T cells. In addition to reduced thymic T cell production, CKD patients display shorter telomeres in both CD4+ and CD8+ T cells. Declining kidney function induces uremic conditions, which alter the intestinal metabolic environment and promote pathogen overgrowth while reducing diversity. This dysbiosis-driven imbalance in the gut microbiota can result in elevated production of uremic toxins, which, in turn, enter the systemic circulation due to compromised gut barrier function under uremic conditions. The accumulation of gut-derived uremic toxins exacerbates local and systemic kidney inflammation. Immune-mediated kidney damage occurs due to the activation of immune cells in the intestine as a consequence of dysbiosis, leading to the production of cytokines and soluble urokinase-type plasminogen activator receptor (suPAR), thereby contributing to kidney inflammation. In this review, we delve into the fundamental mechanisms of immunosenescence in CKD, encompassing alterations in adaptive immunity, gut dysbiosis, and an overview of the clinical findings pertaining to immunosenescence.

Ameliorative Effects of Larazotide Acetate on Intestinal Permeability and Bacterial Translocation in Acute Pancreatitis Model in Rats

BACKGROUND

Intestinal barrier dysfunction in acute pancreatitis (AP) may progress to systemic inflammatory response syndrome (SIRS) and multi-organ failures by causing bacterial translocation. Larazotide acetate (LA) is a molecule that acts as a tight junction (TJ) regulator by blocking zonulin (Zo) receptors in the intestine.

AIMS

In our study, we aimed to investigate the effects of LA on intestinal barrier dysfunction and bacterial translocation in the AP model in rats.

METHODS

Thirty-two male Sprague-Dawley rats were divided into 4 groups; control, larazotide (LAR), AP, and AP + LAR. The AP model was created by administering 250 mg/100 g bm L-Arginine intraperitoneally 2 times with an hour interval. AP + LAR group received prophylactic 0.01 mg/mL LA orally for 7 days before the first dose of L-Arginine. For intestinal permeability analysis, fluorescein isothiocyanate-dextran (FITC-Dextran) was applied to rats by gavage. The positivity of any of the liver, small intestine mesentery, and spleen cultures were defined as bacterial translocation. Histopathologically damage and zonulin immunoreactivity in the intestine were investigated.

RESULTS

Compared to the control group, the intestinal damage scores, anti-Zo-1 immunoreactivity H-Score, serum FITC-Dextran levels and bacterial translocation frequency (100% versus 0%) in the AP group were significantly higher (all p < 0.01). Intestinal damage scores, anti-Zo-1 immunoreactivity H-score, serum FITC-Dextran levels, and bacterial translocation frequency (50% versus 100%) were significantly lower in the AP + LAR group compared to the AP group (all p < 0.01).

CONCLUSIONS

Our findings show that LA reduces the increased intestinal permeability and intestinal damage by its effect on Zo in the AP model in rats, and decreases the frequency of bacterial translocation as a result of these positive effects.

Gut Metabolites Acting on the Gut-Brain Axis: Regulating the Functional State of Microglia

The gut-brain axis is a communication channel that mediates a complex interplay of intestinal flora with the neural, endocrine, and immune systems, linking gut and brain functions. Gut metabolites, a group of small molecules produced or consumed by biochemical processes in the gut, are involved in central nervous system regulation via the highly interconnected gut-brain axis affecting microglia indirectly by influencing the structure of the gut-brain axis or directly affecting microglia function and activity. Accordingly, pathological changes in the central nervous system are connected with changes in intestinal metabolite levels as well as altered microglia function and activity, which may contribute to the pathological process of each neuroinflammatory condition. Here, we discuss the mechanisms by which gut metabolites, for instance, the bile acids, short-chain fatty acids, and tryptophan metabolites, regulate the structure of each component of the gut-brain axis, and explore the important roles of gut metabolites in the central nervous system from the perspective of microglia. At the same time, we highlight the roles of gut metabolites affecting microglia in the pathogenesis of neurodegenerative diseases and neurodevelopmental disorders. Understanding the relationship between microglia, gut microbiota, neuroinflammation, and neurodevelopmental disorders will help us identify new strategies for treating neuropsychiatric disorders.

Gut Microbiota and Biomarkers of Endothelial Dysfunction in Cirrhosis

Our aim was to study the association of endothelial dysfunction biomarkers with cirrhosis manifestations, bacterial translocation, and gut microbiota taxa. The fecal microbiome was assessed using 16S rRNA gene sequencing. Plasma levels of nitrite, big endothelin-1, asymmetric dimethylarginine (ADMA), presepsin, and claudin were measured as biomarkers of endothelial dysfunction, bacterial translocation, and intestinal barrier dysfunction. An echocardiography with simultaneous determination of blood pressure and heart rate was performed to evaluate hemodynamic parameters. Presepsin, claudin 3, nitrite, and ADMA levels were higher in cirrhosis patients than in controls. Elevated nitrite levels were associated with high levels of presepsin and claudin 3, the development of hemodynamic circulation, hypoalbuminemia, grade 2-3 ascites, overt hepatic encephalopathy, high mean pulmonary artery pressure, increased abundance of Proteobacteria and Erysipelatoclostridium, and decreased abundance of Oscillospiraceae, Subdoligranulum, Rikenellaceae, Acidaminococcaceae, Christensenellaceae, and Anaerovoracaceae. Elevated ADMA levels were associated with higher Child-Pugh scores, lower serum sodium levels, hypoalbuminemia, grade 2-3 ascites, milder esophageal varices, overt hepatic encephalopathy, lower mean pulmonary artery pressure, and low abundance of Erysipelotrichia and Erysipelatoclostridiaceae. High big endothelin-1 levels were associated with high levels of presepsin and sodium, low levels of fibrinogen and cholesterol, hypocoagulation, increased Bilophila and Coprobacillus abundances, and decreased Alloprevotella abundance.

Microbial interventions in yak colibacillosis: Lactobacillus-mediated regulation of intestinal barrier

Introduction

The etiology of Escherichia coli in yaks, along with its drug resistance, results in economic losses within the yak breeding industry. The utilization of lactic acid bacteria treatment has emerged as a viable alternative to antibiotics in managing colibacillosis.

Methods

To elucidate the therapeutic mechanisms of Lactobacillus against Escherichia coli-induced intestinal barrier damage in yaks, we employed yak epithelial cells as the experimental model and established a monolayer epithelial barrier using Transwell. The study encompassed four groups: a control group, a model group (exposed to E. coli O78), a low-dose Lactobacillus group (E. coli O78 + 1 × 105CFU LAB), and a high-dose Lactobacillus group (E. coli O78 + 1 × 107CFU LAB). Various techniques, including transmembrane resistance measurement, CFU counting, RT-qPCR, and Western Blot, were employed to assess indicators related to cell barrier permeability and tight junction integrity.

Results

In the Model group, Escherichia coli O78 significantly compromised the permeability and tight junction integrity of the yak epithelial barrier. It resulted in decreased transmembrane resistance, elevated FD4 flux, and bacterial translocation. Furthermore, it downregulated the mRNA and protein expression of MUC2, Occludin, and ZO-1, while upregulating the mRNA expression and protein expression of FABP2 and Zonulin, thereby impairing intestinal barrier function. Contrastingly, Lactobacillus exhibited a remarkable protective effect. It substantially increased transmembrane resistance, mitigated FD4 flux, and reduced bacterial translocation. Moreover, it significantly upregulated the mRNA and protein expression of MUC2, Occludin, and ZO-1, while downregulating the mRNA and protein expression of FABP2 and Zonulin. Notably, high-dose LAB demonstrated superior regulatory effects compared to the low-dose LAB group.

Discussion

In conclusion, our findings suggest that Lactobacillus holds promise in treating yak colibacillosis by enhancing mucin and tight junction protein expression. Furthermore, we propose that Lactobacillus achieves these effects through the regulation of Zonulin.

Elevated Serum Levels of Zonulin Family Peptides in Anticitrullinated Protein Antibody-Positive At-Risk Individuals Without Arthritis

OBJECTIVE

Recent advances imply that early events triggering rheumatoid arthritis (RA) occur at mucosal surfaces. We aimed to evaluate whether intestinal permeability is altered in patients at increased risk of RA, and/or predicts the development of clinical arthritis, by measuring serum zonulin family peptides (ZFP) levels, which are shown to reflect intestinal barrier integrity.

METHODS

Two independent prospective observational cohorts were studied, including subjects with musculoskeletal symptoms and anticitrullinated protein antibodies (ACPA), but without clinical arthritis at baseline. In Sweden, 82 such at-risk patients were compared to 100 age-matched healthy blood donors. In the UK, 307 at-risk patients were compared to 100 ACPA-negative symptomatic controls. ZFP was measured in baseline sera by enzyme-linked immunoassays.

RESULTS

In the Swedish at-risk cohort, ZFP levels were significantly increased in patients compared to controls (mean 41.4 vs 33.6 ng/mL, P < 0.001) and Cox regression analysis showed prognostic value of ZFP for arthritis development (hazard ratio [HZ] 1.04 per ng/mL ZFP increase, 95% CI 1.01-1.07, P = 0.02). Elevated ZFP levels among ACPA-positive at-risk patients compared to symptomatic ACPA-negative controls were confirmed in the UK at-risk cohort (mean 69.7 vs 36.0 ng/mL, P < 0.001), but baseline ZFP were not associated with arthritis development (HR 1.00 per ng/mL ZFP increase, 95% CI 1.00-1.01, P = 0.30).

CONCLUSION

Serum ZFP levels are elevated in ACPA-positive at-risk patients when compared to both healthy blood donors and symptomatic ACPA-negative controls. Thus, gut barrier function may be of importance in RA-associated autoimmunity. A possible prognostic value of serum ZFP merits further investigation, preferably in larger prospective cohorts.

The Hazards of Probiotics on Gut-Derived Pseudomonas aeruginosa Sepsis in Mice Undergoing Chemotherapy

Pseudomonas aeruginosa (P. aeruginosa) is a leading cause of nosocomial infections associated with a high mortality rate and represents a serious threat to human health and the increasing frequency of antimicrobial resistance. Cancer patients are more vulnerable to invasive infection due to ulcerative lesions in mucosal surfaces and immune suppression secondary to chemotherapy. In our in vitro study, we observed that probiotics have the potential to yield beneficial effects on intestinal epithelial cells infected with P. aeruginosa. Additionally, probiotics were found to confer advantageous effects on the innate immunity of mice suffering from Salmonella-induced colitis. As a result, we sought to investigate the impact of probiotics on gut-derived P. aeruginosa sepsis induced by chemotherapy. Following chemotherapy, gut-derived P. aeruginosa sepsis was induced in female C57BL/6 mice aged 6-8 weeks, which were raised under specific-pathogen-free (SPF) conditions in an animal center. Prior to the induction of the sepsis model, the mice were administered 1 × 108 colony-forming units (CFU) of the probiotics, namely Lactobacillus rhamnosus GG (LGG) and Bifidobacterium longum (BL) via oral gavage. We observed that LGG or BL amplified the inflammatory mRNA expression in mice undergoing chemotherapy and suffering from gut-derived P. aeruginosa sepsis. This led to a heightened severity of colitis, as indicated by histological examination. Meanwhile, there was a notable decrease in the expression of antimicrobial peptide mRNA along with reduced levels of zonulin and claudin-2 protein staining within mucosal tissue. These alterations facilitated the translocation of bacteria to the liver, spleen, and bloodstream. To our astonishment, the introduction of probiotics exacerbated gut-derived P. aeruginosa sepsis in mice undergoing chemotherapy. Conclusively, we must be prudent when using probiotics in mice receiving chemotherapy complicated with gut-derived P. aeruginosa sepsis.

The association between serum heat shock protein 72 and intestinal permeability with intestinal microbiota and clinical severity in patients with cerebral infarction

Objectives

We aimed to compare serum heat shock protein 72 (HSP72) and intestinal permeability in patients with cerebral infarction (CI) and healthy individuals to reveal their correlations and link to gut microbiota alterations and clinical severity of CI.

Methods and results

Stool samples of 50 patients with CI and 46 healthy volunteers were analyzed through 16S rRNA gene sequencing to characterize intestinal flora profiles. Serum HSP72 and zonulin were assayed using enzyme-linked immunoassay (ELISA). The obtained data were then subjected to comparative and correlative analysis. We found that the levels of zonulin and serum HSP72 were significantly higher in the CI group compared to the healthy group. Serum HSP72 and zonulin levels were positively correlated in the CI group and correlated positively with the clinical severity of CI. β diversity showed significant differences in intestinal microbiota composition between the two groups. In the CI patient group, the abundance of bacteria Eubacterium_fissicatena_group, Eubacterium_eligens_group, and Romboutsia manifested a remarkably positive correlation with serum HSP72. The abundance of bacteria Eubacterium_fissicatena_group and Acetivibrio had a significantly positive correlation with zonulin levels.

Conclusion

Our findings indicated that an increase in serum HSP72 and zonulin levels was manifested in patients with CI and was related to specific gut microbiota alterations and the clinical severity of CI.

Isoquercitrin alleviates lipopolysaccharide-induced intestinal mucosal barrier damage in mice by regulating TLR4/MyD88/NF-κB signaling pathway and intestinal flora

Intestinal mucosal barrier damage is closely associated with the development of several intestinal inflammatory diseases. Isoquercitrin (IQ) is a natural flavonoid compound derived from plants, which exhibits high antioxidant and anti-inflammatory activity with minimal side effects in humans. Therefore, it shows great potential for preventing and treating intestinal mucosal barrier damage. This study aims to investigate the ameliorative effect and mechanism of IQ on lipopolysaccharide (LPS)-induced intestinal mucosal barrier damage in mice. The mice were treated with IQ for 7 days and then injected with LPS to induce intestinal mucosal barrier damage. The results revealed that IQ treatment alleviated LPS-induced intestinal mucosal barrier damage in mice, which can be evidenced by the improvements in intestinal morphology and the promotion of expression in intestinal tight junctions (ZO-1, Claudin-1, and Occludin), as well as MUC2 mucin. IQ also attenuated intestinal inflammatory responses by inhibiting the TLR4/MyD88/NF-κB signaling pathway and reducing the expression and plasma levels of IL-6, IL-1β, and TNF-α. Furthermore, IQ significantly increased the relative abundance of beneficial bacteria, including Dubosiella, Akkermansia muciniphila and Faecalibaculum rodentium, while suppressing the growth of harmful bacteria such as Mucispirillum schaedleri in the intestinal flora of mice. Consequently, IQ can alleviate the LPS-induced intestinal mucosal barrier damage in mice by inhibiting the TLR4/MyD88/NF-κB signaling pathway and modulating the intestinal flora.

Oral administration of Bifidobacterium longum ES1 reduces endometrial inflammation in women with recurrent pregnancy loss

BACKGROUND

Over-activation of endometrial inflammasome NALP-3 (Nod-like receptor family pyrin domain containing 3) can be found in recurrent pregnancy loss (RPL) women probably due to leaky gut and passage into circulation of lipopolysaccharides (LPS). Leaky gut can be caused by exposure to gluten in RPL women genetically predisposed to celiac disease, positive for Human Leukocyte Antigen (HLA)-DQ2/DQ8 haplotype. Oral administration of Bifidobacterium longum ES1 (GliadinES®) can inactivate gluten peptides toxicity to epithelial gut cells and improve gut barrier.

METHODS

We investigated by enzyme-linked immunoassay: (a) serum levels of LPS and zonuline (a marker of leaky gut); (b) LPS, NALP-3, caspase-1, interleukine (IL)-1β and IL-18 concentration in endometrial fluids, in untreated women with uncomplicated pregnancies (negative HLA-DQ2/DQ8 haplotype) (n = 22) and in women with unexplained RPL, HLA-DQ2/DQ8 positive (n = 22), before and after daily oral administration for 3 months of GliadinES®.

RESULTS

RLP women showed higher serum levels of LPS (p < 0.0001) and higher concentration of LPS (p < 0.0001), NALP-3 (p < 0.01); Caspase-1 (p < 0.0001), IL-1β (p < 0.0001), and IL-18 (p < 0.0001) in endometrial fluids compared to controls. GliadinES® treatment significantly reduced serum levels of both LPS (p < 0.0001) and zonuline (p < 0.01), as well as LPS (p < 0.5), NALP-3 (p < 0.01), Caspase-1 (p < 0.001), IL-1β (p < 0.001), and IL-18 (p < 0.01) concentrations in endometrial fluids of RPL women.

CONCLUSIONS

RPL women positive for HLA-DQ2/DQ8 haplotype show increased circulating and endometrial levels of LPS and endometrial inflammasome NALP-3 over-activation. Oral administration of GliadinES® can reduce gut permeability, decrease serum levels of LPS and, contextually, improve endometrial inflammation in this specific subset of RPL women.

Zonulin as a Biomarker for the Development of Celiac Disease

OBJECTIVES

Increased intestinal permeability seems to be a key factor in the pathogenesis of autoimmune diseases, including celiac disease (CeD). However, it is unknown whether increased permeability precedes CeD onset. This study's objective was to determine whether intestinal permeability is altered before celiac disease autoimmunity (CDA) in at-risk children. We also examined whether environmental factors impacted zonulin, a widely used marker of gut permeability.

METHODS

We evaluated 102 children in the CDGEMM study from 2014-2022. We included 51 CDA cases and matched controls, who were enrolled for 12 months or more and consumed gluten. We measured serum zonulin from age 12 months to time of CDA onset, and the corresponding time point in controls, and examined clinical factors of interest. We ran a mixed-effects longitudinal model with dependent variable zonulin.

RESULTS

Children who developed CDA had a significant increase in zonulin in the 18.3 months (range 6-78) preceding CDA compared to those without CDA (slope differential = β = 0.1277, 95% CI: 0.001, 0.255). Among metadata considered, zonulin trajectory was only influenced by increasing number of antibiotic courses, which increased the slope of trajectory of zonulin over time in CDA subjects (P = .04).

CONCLUSIONS

Zonulin levels significantly rise in the months that precede CDA diagnosis. Exposure to a greater number of antibiotic courses was associated with an increase in zonulin levels in CDA subjects. This suggests zonulin may be used as a biomarker for preclinical CeD screening in at-risk children, and multiple antibiotic courses may increase their risk of CDA by increasing zonulin levels.

Gastrointestinal distress as a potential mediator between stress and periodontal inflammation

OBJECTIVES

Periodontal disease is multifactorial in its aetiology, which encompasses biopsychosocial contributors, including psychological stress. Gastrointestinal distress and dysbiosis have been associated with several chronic inflammatory diseases yet have rarely been investigated with respect to oral inflammation. Given the implications of gastrointestinal distress on extraintestinal inflammation, this study aimed to evaluate the potential role of such distress as a mediator between psychological stress and periodontal disease.

METHODS

Utilizing a cross-sectional, nationwide sample of 828 adults in the USA generated via Amazon Mechanical Turk, we evaluated data collected from a series of validated self-report psychosocial questionnaires on stress, gut-specific anxiety around current gastrointestinal distress and periodontal disease, including periodontal disease subscales targeted at physiological and functional factors. Structural equation modelling was used to determine total, direct and indirect effects, while controlling for covariates.

RESULTS

Psychological stress was associated with gastrointestinal distress (ß = .34) and self-reported periodontal disease (ß = .43). Gastrointestinal distress also was associated with self-reported periodontal disease (ß = .10). Gastrointestinal distress likewise mediated the relation between psychological stress and periodontal disease (ß = .03, p = .015). Given the multifactorial nature of periodontal disease(s), similar results were demonstrated using the subscales of the periodontal self-report measure.

CONCLUSIONS

Associations exist between psychological stress and overall reports of periodontal disease as well as more specific physiological and functional components. Additionally, this study provided preliminary data supporting the potential mechanistic role that gastrointestinal distress plays in connecting the gut-brain and the gut-gum pathways.

Possible Role of Dysbiosis of the Gut Microbiome in SLE

PURPOSE OF REVIEW

The resident gut microbiota serves as a double-edged sword that aids the host in multiple ways to preserve a healthy equilibrium and serve as early companions and boosters for the gradual evolution of our immune defensive layers; nevertheless, the perturbation of the symbiotic resident intestinal communities has a profound impact on autoimmunity induction, particularly in systemic lupus erythematosus (SLE). Herein, we seek to critically evaluate the microbiome research in SLE with a focus on intestinal dysbiosis.

RECENT FINDINGS

SLE is a complex and heterogeneous disorder with self-attack due to loss of tolerance, and there is aberrant excessive immune system activation. There is mounting evidence suggesting that intestinal flora disturbances may accelerate the formation and progression of SLE, presumably through a variety of mechanisms, including intestinal barrier dysfunction and leaky gut, molecular mimicry, bystander activation, epitope spreading, gender bias, and biofilms. Gut microbiome plays a critical role in SLE pathogenesis, and additional studies are warranted to properly define the impact of gut microbiome in SLE, which can eventually lead to new and potentially safer management approaches for this debilitating disease.

Gut microbiota in pre-clinical rheumatoid arthritis: From pathogenesis to preventing progression

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by progressive polyarthritis that leads to cartilage and bone damage. Pre-clinical RA is a prolonged state before clinical arthritis and RA develop, in which autoantibodies (antibodies against citrullinated proteins, rheumatoid factors) can be present due to the breakdown of immunologic self-tolerance. As early treatment initiation before the onset of polyarthritis may achieve sustained remission, optimize clinical outcomes, and even prevent RA progression, the pre-clinical RA stage is showing the prospect to be the window of opportunity for RA treatment. Growing evidence has shown the role of the gut microbiota in inducing systemic inflammation and polyarthritis via multiple mechanisms, which may involve molecular mimicry, impaired intestinal barrier function, gut microbiota-derived metabolites mediated immune regulation, modulation of the gut microbiota's effect on immune cells, intestinal epithelial cells autophagy, and the interaction between the microbiome and human leukocyte antigen alleles as well as microRNAs. Since gut microbiota alterations in pre-clinical RA have been reported, potential therapies for modifying the gut microbiota in pre-clinical RA, including natural products, antibiotic therapy, fecal microbiota transplantation, probiotics, microRNAs therapy, vitamin D supplementation, autophagy inducer-based treatment, prebiotics, and diet, holds great promise for the successful treatment and even prevention of RA via altering ongoing inflammation. In this review, we summarized current studies that include pathogenesis of gut microbiota in RA progression and promising therapeutic strategies to provide novel ideas for the management of pre-clinical RA and possibly preventing arthritis progression.

The Relationships between Intestinal Permeability and Target Antibodies for a Spectrum of Autoimmune Diseases

The worldwide prevalence of autoimmune diseases that have limited treatment options and preventive strategies is rapidly rising. There is growing evidence that the microbiota and the integrity of the intestinal barrier play a role in autoimmune diseases. The potential to evaluate intestinal barrier integrity for susceptible individuals and to determine whether restoring intestinal junction integrity impacts autoimmune diseases is an important area of research that requires further attention. In the intestinal permeability model of autoimmune diseases, the breakdown of the intestinal tight junction proteins (zonulin/occludin) allows bacteria, toxins, undigested dietary proteins, and other antigens to pass into the lumen, thereby increasing the number of inflammatory reactions and the activation of immune cells throughout the body. In this study, we investigate the relationship between zonulin/occludin antibodies, which are used to determine intestinal permeability, with autoantibodies used to diagnose autoimmunity. Our investigation may identify significant levels of circulating autoantibodies in human subjects with intestinal permeability compared to those without intestinal permeability. Furthermore, we identified that significant positive linear correlations between serum occludin/zonulin antibodies and circulating autoantibodies could be used to determine autoimmune diseases.

Intestine Health and Barrier Function in Fattening Rabbits Fed Bovine Colostrum

The permeability of the immature intestine is higher in newborns than in adults; a damaged gut barrier in young animals increases the susceptibility to digestive and infectious diseases later in life. It is therefore of major importance to avoid impairment of the intestinal barrier, specifically in a delicate phase of development, such as weaning. This study aimed to evaluate the effects of bovine colostrum supplementation on the intestinal barrier, such as the intestinal morphology and proliferation level and tight junctions expression (zonulin) and enteric nervous system (ENS) inflammation status (through the expression of PGP9.5 and GFAP) in fattening rabbits. Rabbits of 35 days of age were randomly divided into three groups (n = 13) based on the dietary administration: commercial feed (control group, CTR) and commercial feed supplemented with 2.5% and 5% bovine colostrum (BC1 and BC2 groups, respectively). Rabbits receiving the BC1 diet showed a tendency to have better duodenum morphology and higher proliferation rates (p < 0.001) than the control group. An evaluation of the zonulin expression showed that it was higher in the BC2 group, suggesting increased permeability, which was partially confirmed by the expression of GFAP. Our results suggest that adding 2.5% BC into the diet could be a good compromise between intestinal morphology and permeability, since rabbits fed the highest inclusion level of BC showed signs of higher intestinal permeability.

Role of Gut Microbiota in the Development and Management of Rheumatoid Arthritis: A Narrative Review

Rheumatoid arthritis is an autoimmune condition that damages and inflames the joints. It causes severe disability and lowers the quality of life. While the precise cause of rheumatoid arthritis is still unknown, mounting evidence suggests that the gut microbiota, a diverse colony of bacteria that inhabits the gastrointestinal tract, may play a vital role in the progression and management of this debilitating condition. By evaluating relationships, probable processes, and therapeutic ramifications, this narrative review intends to examine the complex relationship between intestinal microbiota and rheumatoid arthritis. Additionally, for the management of rheumatoid arthritis, the review will assess prospective therapeutic approaches that target the gut flora. Multiple studies have shown that people with rheumatoid arthritis have dysbiosis or an imbalance in their gut microbial ecosystems. Increased intestinal permeability has been linked to changes in the gut microbiota, which allows the transfer of bacterial products into the bloodstream. A search was undertaken through PubMed in June 2023 using keywords like "microbiota", "rheumatoid arthritis" and "treatment". Overall 42 articles were included. Probiotics, prebiotics, and dietary changes are some examples of therapies that can be used to modify the gut microbiota and lessen symptoms, slower the progression of the disease, and enhance therapy results. Understanding the interplay between intestinal microbiota and rheumatoid arthritis will pave the way for innovative and personalized therapeutic interventions that could revolutionize the management of this chronic autoimmune disease.

Investigating the Association Between Diet-Induced "Leaky Gut" and the Development of Prediabetes

INTRODUCTION

Chronic consumption of a high-calorie diet compromises the gut microbiota and the integrity of the intestinal wall, which causes translocation of bacterial lipopolysaccharides (LPS) into the blood. This elicits the secretion of pro-inflammatory cytokines, resulting in inflammation. However, how a high-fat high carbohydrate diet affects intestinal permeability and its possible role in the development of prediabetes have not been investigated. This study investigated the effects of HFHC diet-induced prediabetes on gut microbiota and intestinal permeability in male Sprague Dawley rats.

METHODS

The animals were randomly assigned into the non-prediabetic (NPD) and diet-induced prediabetic (PD) groups (n=6) for 20 weeks. Then, the fecal samples were analyzed to measure the gut microbiota level of Firmicutes, Bacteroidetes, and Proteobacteria in both animal groups. Blood glucose, plasma insulin, serum zonulin, plasma LPS, soluble CD14, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), and intestinal fatty-acid binding protein (IFABP) concentrations were measured.

RESULTS

The PD group had a reduction in the Firmicutes and an increase in Bacteroidetes and Proteobacteria levels compared to those in the NPD group. Blood glucose, insulin concentration, serum zonulin, and plasma sCD14 concentrations in the PD group increased significantly, while plasma LPS concentrations were similar to the NPD group. Concentrations of plasma TNF-α, IL-6, CRP, and IFABP, an intracellular protein expressed in the intestine, increased in PD compared to the NPD group.

CONCLUSIONS

the study results cumulatively suggest that chronic consumption of the HFHC diet may be associated with the dysregulation of gut microbiota, leading to increased intestinal permeability.

Bromelain and ficin proteolytic effects on gliadin cytotoxicity and expression of genes involved in cell-tight junctions in Caco-2 cells

Enzyme therapy for celiac disease (CeD), which digests gliadin into non-immunogenic and non-toxic peptides, can be an appropriate treatment option for CeD. Here, we have investigated the effectiveness of bromelain and ficin on gliadin digestion using in vitro, such as SDS-PAGE, HPLC, and circular dichroism (CD). Furthermore, the cytotoxicity of gliadin and 19-mer peptide before and after digestion with these enzymes was evaluated using the MTT assay in the Caco-2 cell line. Finally, we examined the effect of these treatments along with Larazotide Acetate on the expression of genes involved in cell-tight junctions, such as Occludin, Claudin 3, tight junction protein-1, and Zonulin in the Caco-2 cell line. Our study demonstrated bromelain and ficin digestion effects on the commercial and wheat-extracted gliadin by SDS-PAGE, HPLC, and CD. Also, the cytotoxicity results on Caco-2 showed that toxicity of the gliadin and synthetic 19-mer peptide was decreased by adding bromelain and ficin. Furthermore, the proteolytic effects of bromelain and ficin on gliadin indicated the expression of genes involved in cell-tight junctions was improved. This study confirms that bromelain and ficin mixture could be effective in improving the symptoms of CeD.

Gut microbiota-derived short chain fatty acids act as mediators of the gut-brain axis targeting age-related neurodegenerative disorders: a narrative review

Neurodegenerative diseases associated with aging are often accompanied by cognitive decline and gut microbiota disorder. But the impact of gut microbiota on these cognitive disturbances remains incompletely understood. Short chain fatty acids (SCFAs) are major metabolites produced by gut microbiota during the digestion of dietary fiber, serving as an energy source for gut epithelial cells and/or circulating to other organs, such as the liver and brain, through the bloodstream. SCFAs have been shown to cross the blood-brain barrier and played crucial roles in brain metabolism, with potential implications in mediating Alzheimer's disease (AD) and Parkinson's disease (PD). However, the underlying mechanisms that SCFAs might influence psychological functioning, including affective and cognitive processes and their neural basis, have not been fully elucidated. Furthermore, the dietary sources which determine these SCFAs production was not thoroughly evaluated yet. This comprehensive review explores the production of SCFAs by gut microbiota, their transportation through the gut-brain axis, and the potential mechanisms by which they influence age-related neurodegenerative disorders. Also, the review discusses the importance of dietary fiber sources and the challenges associated with harnessing dietary-derived SCFAs as promoters of neurological health in elderly individuals. Overall, this study suggests that gut microbiota-derived SCFAs and/or dietary fibers hold promise as potential targets and strategies for addressing age-related neurodegenerative disorders.

A specific gut microbiota signature is associated with an enhanced GLP-1 and GLP-2 secretion and improved metabolic control in patients with type 2 diabetes after metabolic Roux-en-Y gastric bypass

Objective

To determine changes in incretins, systemic inflammation, intestinal permeability and microbiome modifications 12 months after metabolic RYGB (mRYGB) in patients with type 2 diabetes (T2D) and their relationship with metabolic improvement.

Materials and methods

Prospective single-center non-randomized controlled study, including patients with class II-III obesity and T2D undergoing mRYGB. At baseline and one year after surgery we performed body composition measurements, biochemical analysis, a meal tolerance test (MTT) and lipid test (LT) with determination of the area under the curve (AUC) for insulin, C-peptide, GLP-1, GLP-2, and fasting determinations of succinate, zonulin, IL-6 and study of gut microbiota.

Results

Thirteen patients aged 52.6 ± 6.5 years, BMI 39.3 ± 1.4 kg/m2, HbA1c 7.62 ± 1.5% were evaluated. After mRYGB, zonulin decreased and an increase in AUC after MTT was observed for GLP-1 (pre 9371 ± 5973 vs post 15788 ± 8021 pM, P<0.05), GLP-2 (pre 732 ± 182 vs post 1190 ± 447 ng/ml, P<0.001) and C- peptide, as well as after LT. Species belonging to Streptococaceae, Akkermansiacea, Rickenellaceae, Sutterellaceae, Enterobacteriaceae, Oscillospiraceae, Veillonellaceae, Enterobacterales_uc, and Fusobacteriaceae families increased after intervention and correlated positively with AUC of GLP-1 and GLP-2, and negatively with glucose, HbA1c, triglycerides and adiposity markers. Clostridium perfringens and Roseburia sp. 40_7 behaved similarly. In contrast, some species belonging to Lachnospiraceae, Erysipelotricaceae, and Rumnicocaceae families decreased and showed opposite correlations. Higher initial C-peptide was the only predictor for T2D remission, which was achieved in 69% of patients.

Conclusions

Patients with obesity and T2D submitted to mRYGB show an enhanced incretin response, a reduced gut permeability and a metabolic improvement, associated with a specific microbiota signature.

Diets Supplemented with Probiotics Improve the Performance of Broilers Exposed to Heat Stress from 15 Days of Age

The poultry sector demands alternative additives to antibiotics that can be used as performance enhancers. Therefore, this experiment was conducted to evaluate the probiotics effects on performance, intestinal health, and redox status of 720 broilers exposed to heat stress from 15 days of age. Eight dietary treatments were evaluated: basal diet (BD) without antibiotic and probiotic (T1); BD supplemented with antibiotic zinc bacitracin (T2), BD supplemented with commercial probiotic of Bacillus subtilis DSM 17,299 (T3), BD supplemented with non-commercial probiotic of Lactococcus lactis NCDO 2118, Lactobacillus delbrueckii CNRZ 327, Escherichia coli CEC15, or Saccharomyces boulardii (T4 to T7), and BD simultaneously supplemented with the four non-commercial probiotics (T8). Feed intake, weight gain, and feed conversion were determined in the period from 1 to 42 days of age. Carcass and cuts yield, abdominal fat deposition, cloacal temperature, weight and length of intestine, activity of myeloperoxidase and eosinophilic peroxidase enzymes in the jejunum, jejunal histomorphometry, relative gene expression in the jejunum (occludin, zonulin, interleukin-8, cholecystokinin, ghrelin, and heat shock protein-70), and liver (heat shock protein-70), in addition to malondialdehyde level and superoxide dismutase activity in the intestine, liver, and blood, were measured in broilers at 42 days old. As main results, broilers fed T1 diet exhibited lower weight gain (3.222 kg) and worse feed conversion (1.70 kg/kg). However, diets containing non-commercial probiotics resulted in up to 3.584 kg of weight gain and improved feed conversion by up to 10%, similar to that observed for broilers of the T2 and T3 groups.

Butyrate restores the fat/lean mass ratio balance and energy metabolism and reinforces the tight junction-mediated intestinal epithelial barrier in prediabetic mice independently of its anti-inflammatory and epigenetic actions

Tissue/cellular actions of butyrate on energy metabolism and intestinal barrier in normal metabolic conditions or prediabetes are still unclear. In this work, we investigated the beneficial effect of dietary supplementation with sodium butyrate on energy metabolism, body mass composition, and intestinal epithelial barrier mediated by tight junction (TJ) in chow diet-fed normal and high-fat diet (HF)-fed prediabetic mice, considering the well-known butyrate action as an epigenetic and inflammatory regulator. Butyrate significantly reduced the fat/lean mass ratio, slightly ameliorated dyslipidemia, restored oral glucose tolerance, and increased basal energy expenditure in prediabetic HF-fed mice but had no effect on control animals. Such effects were observed in the absence of significant alterations in the hypothalamic expression of orexigenic and anorexigenic genes and motor activity. Also, butyrate suppressed the whitening effect of HF on brown adipose tissue but did not affect cell bioenergetics in immortalized UCP1-positive adipocytes in vitro. Butyrate reinforced the intestinal epithelial barrier in HF-fed mice and in Caco-2 monolayers, which involved higher trafficking of TJ proteins to the cell-cell contact region of the intestinal epithelia, without affecting TJ gene expression or the acetylation level of histones H3 and H4 in vivo. All metabolic and intestinal effects of butyrate in prediabetic mice occurred in the absence of detectable changes in systemic or local inflammation, or alterations in endotoxemia markers. Butyrate has no effect on chow diet-fed mice but, in the context of HF-induced prediabetes, it prevents metabolic and intestinal dysfunctions independently of its anti-inflammatory and epigenetic actions.