Serum zonulin is associated with presence and severity of atopic dermatitis in children, independent of total IgE and eosinophil

Allergic rhinitis in children is associated with high serum levels of zonulin

BACKGROUND

Allergic rhinitis (AR) is a common chronic disease characterised by nasal membrane inflammation. Inflammation and epithelial barrier dysfunction play significant roles in the pathogenesis of allergic diseases.

METHODS

The study included 88 children with AR and 50 healthy controls. We measured serum zonulin and haptoglobin levels and compared the groups.

RESULTS

Children with AR had a higher median value of zonulin than healthy children [(11 (4.21-35.95) vs. 8.81 (3.59-47.72) ng/mL, respectively] (p = 0.024). Median value of haptoglobin/zonulin ratio was lower in children with AR [7.91 (0.46-31.93)] compared to healthy controls [11.07 (0.77-74.37), p = 0.011)]. Serum zonulin, haptoglobin levels and the haptoglobin/zonulin ratio did not differ significantly between children with persistent and intermittent AR.

CONCLUSION

High serum zonulin levels and low haptoglobin/zonulin ratios in children show an increased association with AR. Our results may support that inflammation is increased, intestinal permeability and preventive mechanisms to decrease oxidative damage are disrupted in children with AR.

Gut barrier integrity disruption in atopic dermatitis: truth or myth-a case-control study

Background

Gut dysbiosis has been linked to the onset and progression of various diseases, including atopic dermatitis, by disrupting the intestinal barrier integrity. In turn, it allows the translocation of microbes and toxins into the systemic circulation, which triggers an immune response.

Objectives

To measure serum levels of the gut integrity markers claudin 3 and intestinal fatty acid-binding protein in patients with atopic dermatitis.

Methods

This prospective study was conducted on 43 patients with atopic dermatitis. Healthy volunteers (n = 35) served as controls. The serum level of claudin 3 and intestinal fatty acid-binding protein were measured using an enzyme-linked immunosorbent assay for all participants.

Results

There were no significant differences in serum levels of claudin 3 and intestinal fatty acid-binding protein between patients with atopic dermatitis and the control group (P = 0.61 and 0.81, respectively). In addition, there was no significant correlation between the two markers, and different clinical and laboratory parameters (onset of disease, eczema area severity index, other allergic manifestations and serum IgE).

Conclusion

Alterations in the intestinal barrier may be absent in the ethnically distinct group of patients with atopic dermatitis included in our study. Nevertheless, our findings might have been influenced by factors such as the duration of the disease, diet and characteristics of the study population. Further studies are needed to investigate additional biomarkers or mechanisms that may be involved in atopic dermatitis pathogenesis, especially those related to the gut-skin axis.

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.

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.

sCD14 and Intestinal Fatty Acid Binding Protein Are Elevated in the Serum of Patients With Idiopathic Anaphylaxis

BACKGROUND

Intestinal epithelial integrity compromise has been identified in gastrointestinal (GI), atopic, and autoimmune diseases.

OBJECTIVE

Episodes of idiopathic anaphylaxis (IA) are often accompanied by GI manifestations. We, therefore, sought to determine whether surrogate markers of GI permeability were aberrant in this patient population.

METHODS

Serum concentrations of zonulin, intestinal fatty acid binding protein (I-FABP), and soluble CD14 (sCD14) measured in 54 patients with IA were compared with concentrations in healthy controls (HCs); and correlated with clinical and laboratory parameters.

RESULTS

The I-FABP was elevated in sera of patients with IA compared with HCs (median 1,378.0 pg/mL vs 479.0 pg/mL, respectively; P < .001). The sCD14 was also elevated compared with HCs (median 2,017.0 ng/mL and 1,189.0 ng/mL, respectively; P < .001), whereas zonulin was comparable between patients with IA and HCs (median 49.6 ng/mL vs 52.4 ng/mL, respectively; P = .40). The I-FABP was elevated in patients with IA who experienced vomiting and/or diarrhea compared with patients with IA who did not (P = .0091).

CONCLUSIONS

The I-FABP and sCD14 are elevated in the serum of patients with IA. Elevations in these biomarkers of IA provides evidence that increased GI permeability, as is observed in other allergic conditions such as food allergy, is a common finding in those with IA and offers possible insight into the pathogenesis of this disease.

Serum Zonulin Is a Biomarker for Severe Asthma

Zonulin is a regulator of epithelial and endothelial barrier function. It regulates intestinal permeability through disrupting tight junctions. Defective epithelial barrier function is a hallmark of airway inflammation in asthma. This study aimed to investigate the role of zonulin in the pathogenesis of severe asthma. We enrolled 56 adult patients with asthma (29 severe asthma and 27 mild-to-moderate asthma) and 33 normal controls. The clinical data, sera, and lung tissues of the patients were provided by the Cohort for Reality and Evolution of adult Asthma in Korea (COREA) and the Biobank of Soonchunhyang University Bucheon Hospital, South Korea. Serum zonulin levels were estimated using an enzyme-linked immunosorbent assay, and zonulin expression in the bronchial tissue was evaluated by immunohistochemical staining. The serum zonulin levels were significantly higher in patients with severe asthma (51.98 ± 19.66 ng/mL) than in those with mild-to-moderate asthma and normal controls (26.35 ± 13.70 vs. 17.26 ± 10.29 ng/mL, P < 0.001). They significantly correlated with percent predicted forced expiratory volume in one second (%FEV1) (r = -0.35, P = 0.009). The zonulin expression in the bronchial epithelium was greater in patients with severe asthma. A serum zonulin cutoff value to distinguish between severe and mild-to-moderate asthmatics was 38.83 ng/mL. Zonulin may play an important role in the pathogenesis of severe asthma, and serum zonulin could be a potential biomarker for severe asthma.

Zonulin as a Potential Therapeutic Target in Microbiota-Gut-Brain Axis Disorders: Encouraging Results and Emerging Questions

The relationship between dysbiosis and central nervous diseases has been proved in the last 10 years. Microbial alterations cause increased intestinal permeability, and the penetration of bacterial fragment and toxins induces local and systemic inflammatory processes, affecting distant organs, including the brain. Therefore, the integrity of the intestinal epithelial barrier plays a central role in the microbiota-gut-brain axis. In this review, we discuss recent findings on zonulin, an important tight junction regulator of intestinal epithelial cells, which is assumed to play a key role in maintaining of the blood-brain barrier function. In addition to focusing on the effect of microbiome on intestinal zonulin release, we also summarize potential pharmaceutical approaches to modulate zonulin-associated pathways with larazotide acetate and other zonulin receptor agonists or antagonists. The present review also addresses the emerging issues, including the use of misleading nomenclature or the unsolved questions about the exact protein sequence of zonulin.

Evaluation of plasma zonulin level and its relationship with inflammatory cytokines in patients with vitiligo

BACKGROUND

It has been proven that there is an increase in intestinal permeability in some autoimmune diseases. In our study, we purposed to assess intestinal permeability in vitiligo disease by looking at zonulin levels. At the same time, we aimed to examine the correlation of inflammatory cytokines and lipopolysaccharide (LPS) levels with zonulin.

METHODS

Forty-one patients and 41 healthy participants were involved in our study. Blood samples were taken from all patients and controls, and the levels of zonulin, tumor necrosis factor (TNF)-α, interleukin (IL)-6 and LPS were examined.

RESULTS

The mean of zonulin in the patient group was found to be statistically higher than the control group (p < 0.05). A positive correlation was found between zonulin level and IL-6, TNF-α, and LPS levels (p < 0.05). TNF-α and LPS levels in the vitiligo group were significantly higher than in the control group, but there was no such significance in terms of IL-6 levels.

CONCLUSION

We think that serum zonulin level increases and intestinal permeability increases in vitiligo disease.

Assessment of Selected Intestinal Permeability Markers in Children with Food Allergy Depending on the Type and Severity of Clinical Symptoms

Background: Food allergy (FA) has a broad range of symptoms, and clinical manifestations may concern several reactions from one system or organ. Aim: The aim of the study was to assess intestinal permeability (IP) based on the analysis of serum zonulin and bacterial lipopolysaccharides (LPS) levels in children with FA, taking into account the pathomechanism of immune reaction, clinical symptoms of FA and their severity. Material and methods: The study comprised 103 patients aged 7–60 months (median 34); 49 children with IgE-mediated allergy and 25 children with non-IgE-mediated allergy; the reference group comprised 29 children with functional gastrointestinal disorders. IP markers were determined using ELISA. Results: There was no correlation between the severity of clinical symptoms and the level of IP markers in children with FA. Zonulin and LPS levels were significantly higher in children with FA and gastrointestinal symptoms. Zonulin levels in the subgroup of children with non-IgE-mediated FA and gastrointestinal symptoms were significantly higher than in the subgroup of children with IgE-mediated FA and these symptoms. The level of LPS was significantly higher in the subgroup with IgE-mediated FA and atopic dermatitis. Conclusions: Zonulin and LPS levels were significantly higher in children with FA compared to children from the reference group. Zonulin levels were significantly higher in children with non-IgE-mediated FA than in children with IgE-mediated FA.

Claudin-1 Mediated Tight Junction Dysfunction as a Contributor to Atopic March

Atopic march refers to the phenomenon wherein the occurrence of asthma and food allergy tends to increase after atopic dermatitis. The mechanism underlying the progression of allergic inflammation from the skin to gastrointestinal (GI) tract and airways has still remained elusive. Impaired skin barrier was proposed as a risk factor for allergic sensitization. Claudin-1 protein forms tight junctions and is highly expressed in the epithelium of the skin, airways, and GI tract, thus, the downregulation of claudin-1 expression level caused by CLDN-1 gene polymorphism can mediate common dysregulation of epithelial barrier function in these organs, potentially leading to allergic sensitization at various sites. Importantly, in patients with atopic dermatitis, asthma, and food allergy, claudin-1 expression level was significantly downregulated in the skin, bronchial and intestinal epithelium, respectively. Knockdown of claudin-1 expression level in mouse models of atopic dermatitis and allergic asthma exacerbated allergic inflammation, proving that downregulation of claudin-1 expression level contributes to the pathogenesis of allergic diseases. Therefore, we hypothesized that the tight junction dysfunction mediated by downregulation of claudin-1 expression level contributes to atopic march. Further validation with clinical data from patients with atopic march or mouse models of atopic march is needed. If this hypothesis can be fully confirmed, impaired claudin-1 expression level may be a risk factor and likely a diagnostic marker for atopic march. Claudin-1 may serve as a valuable target to slowdown or block the progression of atopic march.

Intestinal Barrier Permeability in Allergic Diseases

The role of intestinal permeability (IP) markers among children and adults with food allergies is not fully understood, and the identification of biological indicators/markers that predict growth retardation in children with allergic diseases and atopy has not been well explained. Studies have shown that patients with atopic diseases respond abnormally to food allergens. Accordingly, differences in the types of immune complexes formed in response to antigen challenges are significant, which seems to underlie the systemic signs of the food allergy. Increased intestinal permeability over the course of a food allergy allows allergens to penetrate through the intestinal barrier and stimulate the submucosal immune system. Additionally, the release of cytokines and inflammatory mediators enhances the degradation of the epithelial barrier and leads to an improper cycle, resulting in increased intestinal permeability. Several studies have also demonstrated increased permeability of the epithelial cells in those afflicted with atopic eczema and bronchial asthma. Ongoing research is aimed at finding various indicators to assess IP in patients with atopic diseases.

Gut Microbiota Parameters Potentially Useful in Clinical Perspective

Interest in gut microbiota analyses is at an all-time high. Gut microbiota is thought to relate to an increasing range of diseases of interest to physicians and nutritionists. Overweight, obesity, response to diet, metabolic syndrome, low grade inflammation, diabetes and colon neoplasms could maybe be observed in microbiota if affordable markers were available. Possible biomarkers like the Firmicutes/Bacteroidetes ratio, the Gram-positive/Gram-negative ratio, the Prevotella/Bacteroides ratio, and the Fusobacterium nucleatum/Faecalibacterium prausnitzii ratio are here reviewed in a narrative way in the attempt to highlight their possible future role in routine practice and clinically relevant diagnostics.

Association between serum zonulin level and severity of house dust mite allergic asthma

BACKGROUND

Increased intestinal permeability, either due to the exposure to antigens in asthmatic patients or due to a barrier defect, plays a critical role in susceptibility to environmental allergens. House dust mite allergy occurs more commonly than any other type of allergy among Egyptian asthmatic patients.

AIM

To assess the relation between serum zonulin level as a marker of increased intestinal permeability and the severity of house dust mite allergic asthma.

METHODS

A case-control study which included 48 patients with house dust mite allergic asthma and 48 healthy control subjects attending the Allergy and Immunology Unit, Microbiology and Immunology Department, Faculty of Medicine, Zagazig University.

RESULTS

A statistically significant difference was detected between the two studied groups with respect to serum IgE and serum zonulin levels (p ˂ 0.001 and ˂ 0.001, respectively). The mean serum zonulin was equal to 258.3 ± 153.01 ng/ml in the asthmatic group and 80 ± 13 ng/ml in the control group. Serum zonulin level significantly increased with the increase of asthma severity (p ˂ 0.001). The cut off value of serum zonulin was ≥ 198 ng/ml, and the area under the curve was 0.76. It displayed sensitivity equal to 80% and specificity equal to 71.4%. Its negative predictive value was equal to 83.3%.

CONCLUSION

Intestinal barrier dysfunction contributes to the pathogenesis of allergic asthma. Serum zonulin level reflects an increase in intestinal permeability. Zonulin acts as prognostic factor of severity in asthma. Correction of the gut barrier defect may have a potential positive prognostic effect in asthma.

Serum zonulin and claudin-5 levels in children with attention-deficit/hyperactivity disorder

OBJECTIVE

This study aimed to investigate serum zonulin and claudin-5 levels of children and adolescents with attention-deficit/hyperactivity disorder (ADHD) and healthy controls by controlling the parameters such as age, sex and body mass index (BMI) percentile which are known to affect these parameters.

METHOD

A total of 80 treatment-naive children and adolescents with ADHD and 40 healthy volunteer controls aged 8-12 years were enrolled in this study. The severities of ADHD symptoms were assessed via parent- and teacher-rated questionnaires. The severity of anxiety and depression symptoms of the children were assessed by the self-report inventories. Serum levels of zonulin and claudin-5 were measured using commercial enzyme-linked immunosorbent assay kits.

RESULTS

The multivariate analysis of covariance (MANCOVA) revealed a significant main effect of groups in the serum zonulin and claudin-5 levels, an effect that was independent of age, sex and BMI percentile. Significant differences were found between the study groups in terms of serum log-claudin-5 levels. However, there was no significant difference between the study groups in terms of serum zonulin levels.

CONCLUSION

These findings provide additional evidence for dysregulation of the blood-brain barrier, especially abnormalities in claudin-5 function, which may be involved in the aetiology of ADHD.Key pointsADHD is one of the most common neurodevelopmental disorders of childhood. Although ADHD is quite common, its aetiology has yet to be fully explained.In recent years, studies on the relationship between intestinal and blood-brain brain barrier permeability and psychiatric disorders have increased.In our study, serum claudin-5 levels were higher in the ADHD group compared to the control group, while serum zonulin levels did not differ between the groups.

Serum vitamin D level is associated with smell dysfunction independently of aeroallergen sensitization, nasal obstruction, and the presence of allergic rhinitis in children

BACKGROUND

Smell dysfunction is highly prevalent worldwide and has adverse effects on quality of life. Smell loss in rhinitis subjects is mainly caused by mechanical obstruction of odorant transmission due to mucosal type 2 inflammation. We determined the association of 25-hydroxyvitamin D (25[OH]D) levels with the severity of smell dysfunction in children.

METHODS

We measured the olfactory threshold score in a total of 518 children (10-12 years old, 264 boys) using the Sniffin' Sticks kit, and the children were divided into tertiles according to olfactory threshold score. We also assessed serum 25[OH]D level, common aeroallergen-specific immunoglobulin E, rhinitis severity with visual analog scale, and the Total Four Symptom Score, and pre- and post-decongestant nasal patency with acoustic rhinometry.

RESULTS

The children with 25(OH)D deficiency had significantly reduced mean olfactory threshold scores when compared to those with 25(OH)D levels of ≥20.0 ng/mL (6.56 ± 3.54 and 7.28 ± 3.87, respectively, P = .036). The proportion of loss of smell function and pre-decongestant nasal patency significantly associated with low 25(OH)D levels (chi-square trend test, P for trend = .007). Likewise, after adjustment for confounders, children with smell loss (third tertile) were significantly associated with low 25(OH)D level (aβ=-0.062, 95% CI=-0.064 to -0.060, P = .009) independent of aeroallergen sensitization, and a low pre-decongestant nasal patency.

CONCLUSIONS

25-Hydroxyvitamin D is significantly associated with smell dysfunction independent of aeroallergen sensitization, nasal obstruction, and the presence of allergic rhinitis. This finding may provide insight into the mechanisms involved in the development of olfactory dysfunction.

Serum zonulin and claudin-5 levels in children with obsessive-compulsive disorder

Background: Obsessive-compulsive disorder (OCD), a chronically debilitating neuropsychiatric disorder, is characterized by distinctive and recurrent obsessions and/or compulsions. An increasing number of evidence indicates that sophisticated interactions between different neurobiological factors play a part in OCD etiology, but the certain underlying mechanisms are still mainly unknown. The present research aimed to explore whether the concentrations of serum zonulin and claudin-5 vary between OCD patients and healthy controls. The present research also intended to explore whether there is an association between zonulin and claudin-5 concentrations and OCD severity.Methods: Twenty-four (13 boys and 11 girls) OCD patients and 24 (13 boys and 11 girls) healthy controls were included in this study. The clinical severity of the OCD symptoms was evaluated by the Children's Yale-Brown Obsessive-Compulsive Scale and the Maudsley Obsessive-Compulsive Inventory. Participants also filled out the Revised Child Anxiety and Depression Scales-Child Version to determine the anxiety and depression levels of the children. Venous blood samples were collected, and serum zonulin and claudin-5 levels were measured.Results: Serum claudin-5 levels were found to be significantly higher in OCD patient whereas serum zonulin levels were not significantly different between the groups.Conclusions: Taken together with our results, our study suggests that dysregulation of the blood-brain barrier, especially claudin-5, may be involved in the etiology of OCD.