UVB: Skin to Gut Study

Purpose:

To explore the potential effects of Narrow-Band Ultra Violet B (NB-UVB) radiation on the intestinal microbiota composition in humans and confirm a regulatory skin-to-gut axis during baseline conditions.

Hypothesis:

Humans exposed to UVB-NB light will show changes in the intestinal microbiota composition with the selection of certain phyla of bacteria.

Justification:

To date, there is no data that describes a biological response to UVB light in the body that affects the intestinal microbiota. Changes in the intestinal microbiota composition caused by NB-UVB phototherapy could be beneficial for patients with chronic/auto-inflammatory diseases like IBD by removing dangerous bacteria, increasing beneficial bacteria, and ultimately modulating immune responses.

Objectives:

• Establish if there is a skin regulatory response towards NB-UVB light in humans.
• Examine what changes in the microbiota composition can be observed on bacterial phyla and class level.
• Determine if this research is worth pursuing in a larger cohort.

Research design:

During the first visit, the skin type will be assessed by using the Fitzpatrick skin type questionnaire.

Subsequently, subjects will be exposed three times within one week to full body NB-UVB light in The Skin Care Centre to a sub erythemic dose (cause slight redness of the skin but not burning). The exposures will happen during the winter months to prevent UVB exposure from the sun during daily activities to interfere with our observations. Stool samples will be collected before the first exposure (2x) and after the last exposure (2x) to analyze the microbiota composition. Also, serum vitamin D (25-hydroxy vitamin D) will be measured before and after the UVB exposure as a marker of previous UVB exposure before the experiment.

Inclusion criteria

• Healthy Caucasian females
• Fitzpatrick skin type I, II or III

Exclusion criteria

• Skin photosensitivity due to medication
• Been on vacation to a sunny destination three months before enrollment
• Visit tanning beds on a regular basis in the past