A guide to studying human dermal adipocytes in situ

Abstract

Dermal white adipose tissue (DWAT) is a main component of human skin, composed of individual lipid-laden mesenchymal cells known as dermal adipocytes (DAs). Besides their well-known role in lipid storage and release, DAs also promote skin immunity, wound healing and hair follicle cycling and are important players in cutaneous neuroendocrinology. The ever-growing insights into DWAT functions, albeit mostly in mice, have invited speculation that it may be involved in multiple skin diseases ranging from fibrosis to alopecia and psoriasis, thus designating human DWAT a clinically relevant, but as yet insufficiently investigated skin compartment. Therefore, this practical, user-friendly guide aims to introduce the techniques available to study human DWAT in situ and ex vivo, including immunohistochemistry, immunofluorescence microscopy and analysis via quantitative immunohistomorphometry. Here, we provide information on a collection of stains comprising pre-adipocyte (Pref1) and mature adipocyte markers (Perilipin1, Caveolin1), as well as various lipid (OilRedO, BODIPY) and histochemical stains (H&E, trichrome) available for use on human DWAT. We offer the reader guidelines on fixing, processing and staining human DAs and highlight caveats and solutions to common problems that one may encounter when studying this fascinating skin compartment. We also suggest standard methods for conducting quantitative immunohistomorphometry on human DWAT and its individual adipocytes to quantify cell size, number, lipid content and fluorescence intensity of adipose-specific markers. Finally, we briefly introduce in situ hybridization, transmission electron microscopy and essentials of magnetic resonance imaging imaging as additional tools for instructively interrogating this largest, but still least-known compartment of human skin.

More than just bricks and mortar: Fibroblasts and ECM in skin health and disease

“…Closely related to the skin fibroblast lineage is the dWAT lineage, consisting of lipid-laden adipocytes and their fibroblast-like progenitors. 44,45 dWAT plays numerous roles in skin, including hair growth modulation [46][47][48] and innate immunity. 49,50 The study by Zhang et al 51 in this issue shows that dermal adipocytes can also prominently reg- While our understanding of dermal ECM composition and biochemistry and of skin fibroblast heterogeneity has grown substantially just over the past few years (Figure 1), many important questions await to be solved for this knowledge to be translated towards therapeutic applications for skin disorders.…”

Age‐dependent facial subcutaneous fat thickness by high‐frequency medical diagnostic ultrasound system

“…An adipocyte size was quantified based on total fat area divided by cell numbers after H&E staining. 9 As shown in Figure 2C, the facial adipocyte in the old was bigger than that in the young about 1.…”

Approaches to the development of 3d bioprinted skin models: the case of natura cosmetics

“…Some authors do not consider hypodermis as part of the skin; however, the hypodermic layer plays an important role in paracrine signaling of the skin, with functions related to skin protection and maintenance of homeostasis. It includes activities that help to protect bacterial infections, control of hair growth cycles, thermogenesis and plays an important role in wound healing, therefore increasing the relevance of the skin model 27 . Thus, studies show that when adipocytes are co-cultured in a monolayer with keratinocytes they stimulate their proliferation and differentiation 28 , whereas adipocytes in co-culture with fibroblasts and keratinocytes demonstrate the same proliferative effect in addition to the recruitment of fibroblasts, which play an important role in wound healing 29 .…”