Human Skin Equivalents

Ex vivo Skin Model

The ex vivo skin model is based on cultivation of biopsies derived from elective plastic surgery. In the ex vivo skin model, the cellular organization and the extracellular matrix reflects that of in vivo human skin closely.

Human Skin Equivalents (HSEs)

1. Leiden Epidermal Model (LEM)

The LEM is a skin model based on cultivation of primary keratinocytes and reflect epidermal structure. During submerged phase, the keratinocytes proliferation and cover the insert fully, whereas during air-exposed phase differentiation occurs. After terminal differentiation, the LEMs represent all major epidermal differentiation layers. This model be upscaled for high-throughput screenings.

2. Full Thickness Model (FTM)

The FTM entails a 3D skin models that consists of both fibroblasts and keratinocytes. The fibroblasts are cultivated in a collagen matrix, thereby mimicking the dermal compartment of the skin. In the FTM, fibroblast-keratinocyte interactions can be studied, as both cell types are present.

3. Fibroblast-Derived Matrix Model (FDM)

In the FDM, also the two main cell types of the skin are cultivated. In the FDM, the fibroblast secreted and modulated the extracellular matrix, which thereby solely consists of cell-derived proteins. The FDM can be generated with specific fibroblasts subtypes that can reflect deeper dermal layers.

Advanced Co-Culture Models

Increased complexity is achieved with advanced co-culture models. Additional cell types can be introduced, which are melanocytes, sebocytes, or adipocytes. To determine host-microbiome interactions, bacteria, viruses, or fungi can be introduced topically. Next-generation advanced models include immunocompetent and skin-on-a-chip models.