Novel Methods for Biodistribution Analysis of Magnetic Nanoparticles In Vivo

Abstract

Melanin is responsible for skin, hair and eyes pigmentation, which is protecting skin from UV damage and skin cancer. Melanin is synthesized and secreted from the melanocytes in the basal layer of the epidermis via organelles called melanosomes. Melanocyte distributes melanin by transferring melanosomes at a ratio of approximately 1:36 to the surrounding basal keratinocytes. However, the exact mechanism that melanin is transferred to keratinocytes in melanocytes is currently unknown. When melanin is consistently increasing or accumulating, it caused dermatological diseases called hyper-pigmentary diseases such as seborrheic keratosis, melanoma. Seborrheic keratosis is a common benign skin tumor which is developed from the proliferation of keratinocytes and accumulated pigment in epidermis. The cause of seborrheic keratosis is unknown, but associated with photodamage and aging. Previous studies are mostly histopathologic analysis, and detail structural study using electron microscopy was not enough. The understanding of melanosome transfer is necessary for studying treatment of hyperpigmentary disorders particularly seborrheic keratosis. In this study, we investigated ultrastructure of melanocytes and surrounding keratinocytes in perilesional seborrheic keratosis and normal skin using transmission electron microscopy. This will help to study the mechanisms behind a wide range of human hyper-pigmentary diseases.