Defining dermal adipose tissue

Abstract

Here, we explore the evolution and development of skin-associated adipose tissue with the goal of establishing nomenclature for this tissue. Underlying the reticular dermis, a thick layer of adipocytes exists that encases mature hair follicles in rodents and humans. The association of lipid-filled cells with the skin is found in many invertebrate and vertebrate species. Historically, this layer of adipocytes has been termed subcutaneous adipose, hypodermis and subcutis. Recent data have revealed a common precursor for dermal fibroblasts and intradermal adipocytes during development. Furthermore, the development of adipocytes in the skin is independent from that of subcutaneous adipose tissue development. Finally, the role of adipocytes has been shown to be relevant for epidermal homoeostasis during hair follicle regeneration and wound healing. Thus, we propose a refined nomenclature for the cells and adipose tissue underlying the reticular dermis as intradermal adipocytes and dermal white adipose tissue, respectively.

Keywords: adipocytes; dermal adipose tissue; dermis; intradermal; skin.

Figure 1

Defining the development and anatomical location of Dermal White Adipose Tissue (DWAT) and Subcutaneous White Adipose Tissue (SWAT) in mammalian skin. The embryonic dermis (yellow) gives rise to DWAT that consists of the intradermal pre-adipocyte and intradermal adipocytes populations in adult mouse skin. DWAT is morphologically and developmentally distinct from SWAT, which is located beneath the panniculus carnosus (white adipocytes). Human skin does not have a detectable panniculus carnosus, however, there are functional and morphological distinctions between DWAT (grey) and SWAT (white).