832 3D Bioprinted vascularized human skin models can be used to screen modulators of angiogenesis for medical and dermo-cosmetic applications

Abstract

Lack of skin vascularization or in contrast its hypervascularization are aggravating factors of some medical pathologies (ulcers and cancers) and dermo-cosmetics troubles (rosacea and dark circles). Thus, developing a suitable in vitro model to screen pharmaceutical and cosmetics ingredients able to stimulate or mitigate the angiogenesis process without changing the normal skin physiology are not easy and hampered by the existence of unreliable in vitro models. Traditional models of skin angiogenesis concentrate on analyzing the co-culture growth of endothelial cells with or without added fibroblasts or keratinocytes. However, these models do not work for topical applications and top-down layering analysis required for complex studies and do not translate well to clinical analysis. Here we describe the creation of a 3D bioprinted vascularized skin model, designed for screening those type of molecules. Human Dermal Microvascular Endothelial Cells, dermal fibroblasts and epidermal keratinocytes were harvested and expanded from juvenile foreskins. Cells were selected for optimal growth and mixed with a bioink into which adhesion proteins were added and cartridged into a CELLINK pneumatic 3D bioprinting system allowing the generation of 3D vascularized printed full thickness skins. Resulting skin models had a vascularization bed created in the lower quadrant of the dermal structure, which was confocal microscopy imaged with anti-CD31 fluorescent labelling. Reduction of epidermal growth factor and pituitary supplement resulted in the sequential reduction and cell death of the vascular bed over 14 days, whilst continual supplementation maintains the model and cellular interconnections. With 3D Bioprinting we can produce hundreds of models in one afternoon giving the potential to screen many combinations of molecules before moving to more expensive clinical experimentations.