Functional Testing of a Skin Topical Formulation In Vivo : Objective and Quantitative Evaluation in Human Skin Scarring Using a Double-Blind Volunteer Study with Sequential Punch Biopsies

Abstract

Objective:

Many topicals claim an efficacious role in skin scar management with limited evidence. Our aim is to present a clear format for functional testing of a skin scarring ointment, using noninvasive and invasive measurements, categorizing findings under the physiological, structural, and mechanical parameters of a scar.

Approach:

A double-blinded, randomized volunteer research study of 45 subjects receiving an ointment composing of natural ingredients against a widely used antiscarring topical used as a positive control with temporal sequential punch biopsies (up to 16 weeks) was evaluated using noninvasive quantitative devices and validated by gene and protein studies.

Results:

Outcome measures included physiological, mechanical, and structural features of scars. Significant non-invasive findings included an increase in skin hydration (p < 0.05) at week (W) 4, 8, and 12, and elasticity (W16; p = 0.009). These findings were validated by immunohistochemistry (IHC) and quantitative real-time PCR (qRT-PCR). Hyaluronic acid IHC (W4 p = 0.014, W12 p = 0.034, and W16 p = 0.042), qRT-PCR (W16 p = 0.049); Collagen I (W16 p = 0.034, and 0.049) IHC and qRT-PCR, respectively. Collagen III qRT-PCR (W12 p = 0.035, and W16 p = 0.32); elastin IHC (W12 p = 0.044); and fibronectin IHC (W4 p = 0.009, W12 p = 0.038, and W16 p = 0.026).

Innovation:

Utilizing this model allows for quantitative, objective evaluation of any topical, where previously there has been a paucity of relevant methods to evaluate their effect.

Conclusions:

The positive effect of a topical formulation with an unknown mechanism of action on early cutaneous scar maturation over progressive sequential time points is now evidenced using noninvasive and invasive techniques with the findings categorized on the basis of scarring parameters.