The study will entail 1 cohort with a randomized repeated biopsy collection time. Three skin punch biopsies (3 mm) of the lower back will be taken from each volunteer on day 0. One biopsy sample taken on day 0 will serve as a baseline measurement for the repeated samples regarding the histology, immunohistochemistry, and RNA sequencing (RNA-seq) or real-time reverse transcription polymerase chain reaction (qRT-PCR) assessments.
Repeated biopsies of the same location as on day 0 will be taken on day 7, 14 or 21 (biopsy lesion and day randomized), and day 28, 42 or 56 (biopsy lesion and day randomized) for all subjects. The observation biopsy (biopsy lesion randomized) will serve as primary biopsy and followed for all measurements.

Wound Healing

Observation of wound healing after skin biopsy

Observation of wound healing

Centre for Human Drug Research

Wound Healing in Healthy Volunteers

A Single-arm, Observational Study to Explore and Characterize Wound Healing After Skin Punch Biopsies in Healthy Volunteers

Histology with hematoxylin and eosin (HE) staining

Local skin biomarkers for wound healing related biomarkers (e.g. VEGF-A, TNFα, IL-8, TLSP, MMP-3, IL-4) by transdermal analysis patch (TAP)

Erythema grading scale. Wounds are scored on the basis of redness of the wound (from better to worse: absence, mild, moderate, or severe).

Skin microbiome (healthy and biopsy lesions). Collection of skin culture samples is a non-invasive procedure where a sterile polyester flock tip per site is passed along the surface of the 3 different areas. The target areas are i) regions surrounding one of the biopsy lesions on the lower back, ii) a control site of healthy, unaffected skin in proximity of a biopsy lesion and iii) a control area on the lower back with a minimum distance of 10cm from a biopsy site. The skin swab will be placed in a 2 ml lysis tube containing DNA/RNA shield to stabilize and preserve the DNA. The DNA extraction will be performed using adapted DNA extraction method based on the Zymo Research fecal DNA extraction methodology. After DNA extraction, the variable regions 3 and 4 of the 16S rRNA gene are amplified giving an amplicon of around 450 base pairs. This amplicon is analyzed by capillary systems using standard protocols.

Immunohistochemistry with wound healing related biomarkers (e.g. CD31, collagen I, collagen III, aSMA, fibronectin)

RNA-seq or qRT-PCR for wound healing related biomarkers (e.g. VEGFα, TGFβ1, TGFβ2, TGFβ3, PDGF, CTGF, TNF, IL-1B, IL-4, GM-CSF, IL-6, IL-10, MMP1, MMP3, OSM, LOX)

Red-Yellow-Black (RYB) wound assessment scale. Wounds are scored based on the color of the wound bed (from healthy to least healthy: red, yellow, or black). The least healthy color is chosen in multi-color wounds. Furthermore, a humidity subscale (dry, humid, or wet) is added to further classify the health status of the wounds.

POSAS. The observer scale of the POSAS consists of six items (vascularity, pigmentation, thickness, relief, pliability and surface area). All items are scored on a scale ranging from 1 ('like normal skin') to 10 ('worst scar imaginable'). The sum of the six items results in a total score of the POSAS observer scale. Categories boxes are added for each item:
Vascularity category: pale, pink, red, purple, mix
Pigmentation category: hypo, hyper, mix
Thickness category: thicker, thinner
Relief category: more, less, mix
Surface area category: expansion, contraction, mix Furthermore, an overall opinion is scored on a scale ranging from 1 to 10. All parameters are preferably compared to normal skin on a comparable anatomic location.

NRS pruritus and pain. The pruritus and pain NRS are single-question assessment tools that are used to assess the subject's worst itch and pain in the previous time interval. Subjects will be asked the following question; "on a scale of 0 - 100, with 0 being no itch, and 100 being the worst itch imaginable, how would you rate your average degree of itch of all biopsy sites combined experienced during the previous time interval?" and "on a scale of 0 - 100, with 0 being no pain, and 100 being the worst pain imaginable, how would you rate your average degree of pain of all biopsy sites combined experienced during the previous time interval?"

keloid/nicotine

Wound Healing in Healthy Volunteers

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