The Role of Vitamin D in Corneal Epithelial Barrier Function, Ocular Microbiome, Ocular Inflammation, and Visual Acuity of Children With Allergic Conjunctivitis

A double-blind study to evaluate the role of vitamin D in corneal epithelial barrier function, ocular microbiome, ocular inflammation, and visual acuity of children with allergic conjunctivitis.

Study Overview

• Status: Enrolling by invitation
• Conditions: Allergic Conjunctivitis
• Intervention / Treatment: Other: Placebo; Other: Vitamin D

Detailed Description

The prevalence of allergic conjunctivitis (AC) has rapidly increased in recent decades, resulting in a significant global public health concern. The ocular surface is a unique mucosal immune compartment in which immunological features act in concert to foster a tolerant microenvironment (immune privilege). The corneal epithelial barrier is the first line of defense that forms a protective barrier against pathogens, pollutants, and allergens. The ocular microbiota has a role in maintaining the homeostasis of the ocular surface and preservation of barrier function. Vitamin D functions as enforcing intercellular junctions and maintaining intestinal epithelial barrier integrity; metabolites from the gut microbiota may also regulate expression of vitamin D receptor (VDR). Low serum vitamin D levels have been shown to predispose to a variety of allergic disorders. A recent study shows that corneas contain vitamin D and VDR; vitamin D enhances corneal epithelial barrier function. However, research data of the role of vitamin D in ocular microenvironment of AC are insufficient and controversial. In recent research, the investigators found allergic inflammation of ocular surface weakened corneal epithelial barrier, modulated the signal pathway of retinal pigment epithelial cells, and enhanced scleral tissue remodeling, resulting in myopia in progression. However, there are few studies available to investigate the role of vitamin D in ocular surface microenvironment, ocular inflammation, and visual acuity in AC. Moreover, understanding the interaction of vitamin D, ocular microbiota, and ocular inflammation may provide a new target for the development of therapeutic interventions of ocular allergy and restore visual function.

• Study Type: Interventional
• Enrollment (Estimated): 150
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Taiwan
  • Taichung, Taiwan, 404
    • China Medical University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Children aged 6-18 years with allergic conjunctivitis (AC) diagnosed by ophthalmologists or allergists

Exclusion Criteria:

1. Previous eye surgery
2. Active eye infection
3. Any active inflammatory eye disease except AC
4. Systemic steroid use within 28 days of study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Control group; placebo	Other: Placebo; Placebo
Experimental: Treatment group; Vitamin D (2000IU/day) for 6 months	Other: Vitamin D; Vitamin D (2000IU/day) for 6 months

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Levels of vitamin D	Vitamin D will be measured in a blood sample by ELISA to determine baseline status.	Month 0
Levels of vitamin D	Vitamin D will be measured in a blood sample to follow the change from baseline in vitamin D level at month 6.	Month 6
Total IgE	Plasma total IgE concentration will be measured by microparticle immunoassay (IMx analyzer, Abbott Laboratories, Abbott Park, IL) and ELISA to determine baseline status.	Month 0
Total IgE	Plasma total IgE concentration will be measured by microparticle immunoassay (IMx analyzer, Abbott Laboratories, Abbott Park, IL) and ELISA to follow the change from baseline in total IgE at month 6.	Month 6
Allergen-specific IgE	Plasma allergen-specific IgE will be measured by BioIC ®.	Month 0
Single nucleotide polymorphism of vitamin D receptor and vitamin D binding protein	Single nucleotide polymorphism (SNP) genotyping will be performed in a blood sample by using TaqMan SNP genotyping assays.	Month 0
Microbiome	Nasal, subconjunctival and anal swabs will be used to detect ocular surface, nasal and intestinal microbiome by using 16S rRNA sequencing to determine baseline status.	Month 0
Microbiome	Nasal, subconjunctival and anal swabs will be used to detect ocular surface, nasal and intestinal microbiome by using 16S rRNA sequencing, and to follow the change from baseline in microbiome at month 6.	Month 6

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
mini-Rhinoconjunctivitis Quality of Life Questionnaire (mini-RQLQ)	mini-RQLQ is to measure a the level of severity of a set of symptoms of functional impairments due to rhinoconjunctivitis. 14 questions each range 0-6 (6 is most severe). Total range 0-84 (higher scores reflect lower quality of life.)	Month 0 to Month 6

Collaborators and Investigators

• Sponsor: China Medical University Hospital

Study record dates

Study Major Dates

• Study Start (Actual): August 8, 2022
• Primary Completion (Estimated): July 31, 2025
• Study Completion (Estimated): July 31, 2025

Study Registration Dates

• First Submitted: April 21, 2023
• First Submitted That Met QC Criteria: April 21, 2023
• First Posted (Actual): May 3, 2023

Study Record Updates

• Last Update Posted (Actual): July 3, 2024
• Last Update Submitted That Met QC Criteria: June 30, 2024
• Last Verified: June 1, 2024

More Information

Terms related to this study

• Keywords: vitamin D; microbiota; visual acuity; allergic conjunctivitis, immune privilege; corneal epithelial barrier; ocular microenvironment; vitamin D receptor gene polymorphism; ocular surface and intraocular inflammation
• Additional Relevant MeSH Terms: Pathologic Processes; Immune System Diseases; Hypersensitivity, Immediate; Eye Diseases; Hypersensitivity; Conjunctival Diseases; Inflammation; Conjunctivitis; Conjunctivitis, Allergic; Physiological Effects of Drugs; Micronutrients; Vitamins; Bone Density Conservation Agents; Vitamin D
• Other Study ID Numbers: CMUH111-REC1-044

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No