Oral vitamin D modulates the epidermal expression of the vitamin D receptor and cathelicidin in children with atopic dermatitis

Changes and clinical significance of serum vitamin A, 25-(OH)D3, TG2, IL-4 and IL-13 levels in children with eczema

The study aims to examine fluctuations in the levels of serum vitamin A, 25-(OH)D3, TG2, IL-4, and IL-13 in pediatric eczema patients and explore how these changes relate to the severity of the condition. This retrospective study analyzed the clinical data of 159 children with eczema admitted to the hospital from May 2023 to October 2024 as the experimental group. The patients were divided into groups according to the severity of the disease: mild group(≤ 25 points, n = 45), moderate group(25-50 points, n = 72) and severe group(>50 points, n = 42). Collect each group of serum serum vitamin A, 25- (OH) D3, TG2, IL-4, and IL-13 levels and analyze them. The improvements in serum vitamin A, 25-(OH)D3, TG2, IL-4, and IL-13 levels in each group of children after 3 months of treatment were further analyzed. As eczema severity escalated, there was a progressive decline in Vit A and 25-(OH)D3 levels, while TG2, IL-4, and IL-13 levels correspondingly rose (P < 0.05). Pearson correlation analysis revealed a significant negative correlation between serum Vit A and 25-(OH)D3 levels and the SCORAD scores in children with eczema (P < 0.05). Conversely, TG2, IL-4, and IL-13 levels exhibited positive correlations with the SCORAD scores (P < 0.05). 25-(OH)D3 had the highest AUC for diagnosing the severity of eczema, which was significantly better than serum vitamin A, TG2, IL-4, and IL - 13 ( all P < 0.05 ). After 3 months of treatment, the serum levels of vitamin A, 25-(OH)D3, TG2, IL-4, and IL-13 in all groups were significantly improved (P < 0.05). Vit A, 25-(OH)D3, TG2, IL-4, and IL-13 correlate with the severity of eczema symptoms. The severity of the disease can be evaluated clinically according to the changes in these serum indicators, and the clinical application value is high.

CYP24A1 is overexpressed in keloid keratinocytes and its inhibition alters profibrotic gene expression

Background

Keloids are disfiguring, fibrotic scar-like lesions that are challenging to treat and commonly recur after therapy. A deeper understanding of the mechanisms driving keloid formation is necessary for the development of more effective therapies. Reduced vitamin D receptor (VDR) expression has been observed in keloids, implicating vitamin D signaling in keloid pathology. Vitamin D exhibits anti-proliferative and anti-inflammatory properties, suggesting it could have therapeutic utility in keloid disorder. The current study investigated vitamin D-regulated gene expression in keloid keratinocytes and the effects of inhibiting an enzyme involved in vitamin D metabolism on the phenotype of keloid-derived keratinocytes.

Methods

Normal and keloid-derived primary keratinocytes were isolated from normal skin and keloid lesions, respectively, and were cultured in the absence or presence of vitamin D. In some experiments, inhibitors of the vitamin D metabolizing enzyme CYP24A1, ketoconazole or VID400 were added in the absence or presence of vitamin D. Cellular proliferation, migration and gene expression were measured.

Results

We observed significant overexpression of CYP24A1 mRNA in keloid versus normal keratinocytes and increased CYP24A1 protein levels in keloids versus normal skin. CYP24A1 encodes 24 hydroxylase and is induced by vitamin D in a feedback loop that regulates vitamin D levels; thus, inhibition of CYP24A1 activity may locally increase active vitamin D levels. Ketoconazole, a non-specific cytochrome P-450 inhibitor, reduced proliferation of keloid and normal keratinocytes, but VID400, a specific CYP24A1 inhibitor, only significantly affected keloid keratinocyte proliferation. Neither inhibitor significantly reduced keratinocyte migration. The two inhibitors had different effects on vitamin D target gene expression in keratinocytes. Specifically, ketoconazole treatment reduced CYP24A1 expression in normal and keloid keratinocytes, whereas VID400 increased CYP24A1 expression. Both inhibitors decreased expression of profibrotic genes, including periostin and hyaluronan synthase 2, in keloid-derived cells. Combined treatment of keloid keratinocytes with vitamin D and ketoconazole or VID400 increased the effects of vitamin D treatment on target genes, although the effects were gene- and cell type-specific.

Conclusions

The data suggest that reduction of vitamin D inactivation with CYP24A1 inhibitors may reduce profibrotic gene expression in keloid-derived cells. Therefore, CYP24A1 inhibitors may serve as adjunctive therapies to suppress keloid-associated gene expression changes.

Differential Expression of Proteins Involved in Skin Barrier Maintenance and Vitamin D Metabolism in Atopic Dermatitis: A Cross-Sectional, Exploratory Study

Atopic dermatitis (AD) is a chronic inflammatory skin disorder influenced by proteins involved in skin barrier maintenance and vitamin D metabolism. Using an intra-patient design, this study compared protein expression in intra-lesional (IL) and peri-lesional (PL) skin biopsies from AD patients and examined associations between protein levels, vitamin D status, and clinical features. Forty-four biopsies from twenty-two AD patients were analyzed using antibody microarrays targeting twelve proteins. IL samples had significantly higher total protein levels than PL samples, with a mean difference of 77.7% (p < 0.001). Several proteins, including cathelicidin, cingulin, occludin, filaggrin, and the vitamin D receptor, were upregulated in IL samples. Patients with vitamin D levels below 30 ng/mL showed higher expression of CYP24A (p = 0.054), alpha-catenin (p = 0.043), and haptoglobin (p = 0.033). Increased EASI scores (≥16) were associated with elevated expression of CYP24A (p = 0.024), CYP27B (p = 0.044), filaggrin (p = 0.027), occludin (p = 0.049), and claudin-1 (p = 0.052). Multivariate regression analysis identified significant correlations between protein expression, skin prick test positivity, and low vitamin D levels. These findings suggest that proteins related to epithelial barrier function and vitamin D metabolism are highly upregulated in IL skin regions, offering potential therapeutic targets for improving both skin barrier function and overall disease severity in AD patients.

Effect of weekly vitamin D supplementation on the severity of atopic dermatitis and type 2 immunity biomarkers in children: A randomized controlled trial

BACKGROUND

Vitamin D (VD) deficiency is common among patients with atopic dermatitis (AD) and often associated with severity. However, randomized trials of VD supplementation in AD have had equivocal results, and there is little information regarding the effect of VD supplementation on type 2 immunity in AD patients.

OBJECTIVES

To investigate the efficacy of VD supplementation to decrease severity of AD and to alter type 2 immunity biomarkers.

METHODS

We performed a randomized, double-blind, placebo-controlled trial. We randomly assigned 101 children with AD to weekly oral vitamin D3 (VD3) or placebo for 6 weeks. The primary outcome was the change in the Severity Scoring of AD (SCORAD).

RESULTS

Mean age of subjects was 6.3 ± 4.0 years, and baseline SCORAD was 32 ± 29. At baseline, 57% of children were VD deficient, with no difference between groups. Change in 25(OH)D was significantly greater with VD3 than placebo (+43.4 ± 34.5 nmol/L vs. +2.3 ± 21.2 nmol/L, p < 0.001). SCORAD change at 6 weeks was not different between VD and placebo (-5.3 ± 11.6 vs. -5.5 ± 9.9, p = 0.91). There were no significant between-group differences in change of eosinophil counts, total IgE, Staphylococcal enterotoxin specific IgE, CCL17, CCL22, CCL27, LL-37 or Staphylococcus aureus lesional skin colonization. Vitamin D receptor (VDR) gene single nucleotide polymorphisms FokI, ApaI and TaqI did not modify subjects' response to VD supplementation.

CONCLUSIONS

Among children with AD, weekly VD supplementation improved VD status but did not modify AD severity or type 2 immunity biomarkers compared to placebo (ClinicalTrials.gov NCT01996423).

Vitamin D and allergic diseases

In recent years, the relationship between vitamin D and allergic diseases has received widespread attention. As a fat-soluble vitamin, vitamin D plays a crucial role in regulating the immune system and may influence the onset and progression of diseases such as atopic dermatitis, allergic rhinitis, and asthma. To understand the underlying mechanisms, we have summarized the current research on the association between vitamin D and allergic diseases. We also discuss the impact of vitamin D on the immune system and its role in the course of allergic diseases, particularly focusing on how vitamin D supplementation affects the treatment outcomes of these conditions. We aim to provide a theoretical basis and practical guidance for optimizing the management and treatment of allergic diseases by modulating vitamin D levels.

Role of antioxidants supplementation in the treatment of atopic dermatitis: a critical narrative review

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by itching, epidermal barrier dysfunction, and an unbalanced inflammatory reaction. AD pathophysiology involves a dysregulated immune response driven by T helper-2 cells. Many factors, including reactive oxygen species (ROS), are involved in AD pathogenesis by causing cellular damage and inflammation resulting in skin barrier dysfunction. This narrative review aims to provide a comprehensive overview of the role of natural molecules and antioxidant compounds, highlighting their potential therapeutic value in AD prevention and management. They include vitamin D, vitamin E, pyridoxine, Vitamin C, carotenoids, and melatonin. Some studies report a statistically significant association between antioxidant levels and improvement in AD, however, there are conflicting results in which antioxidant supplementation, especially Vitamin D, did not result in improvement in AD. Therefore, the clinical efficacy of these dietary nutritional factors in the treatment of AD needs to be further evaluated in clinical trials. Meanwhile, antioxidants can be incorporated into the management of AD patients in a personalized manner, tailored to the severity of the disease, comorbidities, and individual needs.

Dietary Interventions in Atopic Dermatitis: A Comprehensive Scoping Review and Analysis

BACKGROUND

This scoping review aims to critically assess gaps in the current literature on atopic dermatitis (AD) by evaluating the overall effectiveness of dietary interventions. Through a comprehensive analysis that follows the Preferred Reporting Item for Systematic Review and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines, we conducted a thorough search on the Web of Science database in May 2023 using specific search strategies to identify all relevant studies on the research topic.

SUMMARY

A total of 104 full-text articles were included for review. Our synthesis identified seven notable categories of dietary interventions for AD, showcasing the diversity of interventions utilized. This includes vitamin supplementation, probiotic and prebiotic supplementation, dietary fat, biological compounds, foods from natural sources, major nutrients, and diet-related approaches. Further analyses stratified by targeted populations revealed a predominant focus on pediatrics, particularly in probiotic supplementation, and on adults, with an emphasis on vitamin D and E supplementation.

KEY MESSAGES

Despite most dietary interventions demonstrating overall effectiveness in improving AD severity and its subjective symptoms, several significant gaps were identified. There was a scarcity of studies on adults and whole-diet interventions, a prevalence of short-term interventions, heterogeneity in study outcomes, designs, and population, occasional disparity between statistical significance and clinical relevance, and a lack of a comprehensive multidisciplinary approach. Nonetheless, these findings offer valuable insights for future AD research, guiding additional evidence-driven dietary interventions and informing healthcare professionals, researchers, and individuals, advancing both understanding and management of AD.

A role for vitamin D and the vitamin D receptor in keloid disorder

Keloids are disfiguring fibroproliferative lesions that can occur in susceptible individuals following any skin injury. They are extremely challenging to treat, with relatively low response rates to current therapies and high rates of recurrence after treatment. Although several distinct genetic loci have been associated with keloid formation in different populations, there has been no single causative gene yet identified and the molecular mechanisms guiding keloid development are incompletely understood. Further, although it is well known that keloids are more commonly observed in populations with dark skin pigmentation, the basis for increased keloid risk in skin of colour is not yet known. Because individuals with dark skin pigmentation are at higher risk for vitamin D deficiency, the role of vitamin D in keloid pathology has gained interest in the keloid research community. A limited number of studies have found lower serum vitamin D levels in patients with keloids, and reduced expression of the vitamin D receptor (VDR) in keloid lesions compared with uninjured skin. Vitamin D has documented anti-inflammatory, anti-proliferative and pro-differentiation activities, suggesting it may have a therapeutic role in suppression of keloid fibrosis. Here we review the evidence supporting a role for vitamin D and VDR in keloid pathology.

From gut to skin: exploring the potential of natural products targeting microorganisms for atopic dermatitis treatment

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease. Recent studies have revealed that interactions between pathogenic microorganisms, which have a tendency to parasitize the skin of AD patients, play a significant role in the progression of the disease. Furthermore, specific species of commensal bacteria in the human intestinal tract can have a profound impact on the immune system by promoting inflammation and pruritogenesis in AD, while also regulating adaptive immunity. Natural products (NPs) have emerged as promising agents for the treatment of various diseases. Consequently, there is growing interest in utilizing natural products as a novel therapeutic approach for managing AD, with a focus on modulating both skin and gut microbiota. In this review, we discuss the mechanisms and interplay between the skin and gut microbiota in relation to AD. Additionally, we provide a comprehensive overview of recent clinical and fundamental research on NPs targeting the skin and gut microbiota for AD treatment. We anticipate that our work will contribute to the future development of NPs and facilitate research on microbial mechanisms, based on the efficacy of NPs in treating AD.