In vivo evaluation using Reflectance Confocal Microscopy and Skin Bioengineering of the prevention of actinic keratosis lesions using topical formulations of Retinyl Palmitate, Niacinamide, and their combination

Abstract

Actinic keratosis (AK) is characterized by skin lesions that precede a type of non-melanoma skin cancer, which corresponds to approximately 30% of malignant tumors reported in Brazil. The disease manifests from subclinical lesions originating from initial keratinocyte dysplasia in areas of skin with chronic sun exposure. Topical retinyl palmitate may be an alternative for preventing AK, as retinoids regulate the proliferation and differentiation of keratinocytes, maintain epidermal thickness, and address photoaging. Another promising active is niacinamide, which acts on inflammation, improves skin barrier function, and prevents UV-induced immunosuppression. Additionally, reflectance confocal microscopy (RCM) is a rapid and non-invasive technology for assessing the structure of the epidermis down to the superficial reticular dermis in high resolution, making it promising for detecting initial subclinical lesions. Cutaneous bioengineering techniques, also known as biophysical skin parameters, are relevant in this context as they evaluate viscoelasticity and barrier function to attest to the efficacy of cosmetic products. Based on the presented scenario, the objective of this project is to evaluate the incidence of signs of subclinical lesions and the prevention of AK lesion development through a prospective, randomized, placebo-controlled, evaluator-blind comparative clinical trial. This trial will utilize RCM and cutaneous bioengineering techniques, involving the development and use of topical emulsions containing 1% retinyl palmitate, 5% niacinamide, and a combination of both actives. Furthermore, a follow-up study will be conducted to monitor AK prevention up to one year after the end of cosmetic product use, aiming to ensure the maintenance of skin health.