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BioVaSc-TERM - a platform technology to engineer human barrier models

: Rossi, Angela; Schweinlin, Matthias; Steinke, Maria; Groeber, Florian; Walles, Heike

ALTEX Proceedings 5 (2016), Nr.1, S.175
ISSN: 2194-0479
European Society for Alternatives to Animal Testing (EUSAAT Congress) <17, 2016, Linz>
Fraunhofer IGB ()

In vitro test systems gain increasing importance to improve predictivity and to reduce animal experiments. Of special interest are barrier tissues that guard into the human body. These barriers are formed by highly specialized tissues such as skin, airways and intestine. However, to recapitulate these tissues, researchers are currently restricted by a lack of suitable supporting scaffolds. In this study, we present a biological scaffold based on decellularized porcine jejunum segments (BioVaSc®-TERM) that offers a natural environment for cell growth and differentiation. Employing the scaffold, human barrier models of the skin, the airways, and the intestine are generated that mimic the natural histological architecture and functionality and can be used for efficacy and safety testing of drugs, biologicals and vaccines.
Materials and methods
Following explantation and decellularization, the BioVaSc® was fixed between two metal cylinders. For airway and skin models, primary fibroblasts were seeded on the former luminal side of the jejunum. After 1 days and 5 days, respectively, primary epithelial cells were added and cultured for further 20 days and 11 days under air-liquid interface. For intestinal models, Caco-2 cells were seeded on the BioVaSc® and cultured for 14 days.
Results and discussion
Preserving the complex composition and three-dimensional ultrastructure of the extracellular matrix, the BioVaSc® allows generating tissue models close to the in vivo situation [1]. Skin equivalents comprise anatomical and cellular characteristics of native human skin. Fibroblasts migrate into the scaffold forming a homogeneously populated dermal compartment. Keratinocytes develop 8-10 viable layers. Immunofluorescence staining confirmed the close mimicry to native skin, thus enabling to study efficacy testing of drugs [2]. By reseeding the former vessels of the porcine jejunum with human endothelial cells and the subsequent perfusion using bioreactor systems, the scaffold can be used to generate vascularized skin equivalents [3]. The BioVaSc®
is also suitable to create three-dimensional airway test systems [4]. They consist of a connective tissue department seeded with fibroblasts and a polarized ciliated respiratory epithelium that is anchored to the lamina propria-like connective tissue. Immunohistochemical staining revealed the similarity to the native tissue and that the epithelium produces major gel-forming respiratory mucins. Thus, the airway models comprise features to investigate biocompatibility, distribution and metabolization of inhalable drugs. Histological assessment of the intestinal models confirmed a confluent monolayer of cubic epithelial cells on the BioVaSc®. Cell polarization was shown by SEM analysis showing the typical microvilli covering the apical cell membrane of the intestinal epithelium [5].
The presented models show tissue specific barrier properties, such as stratification of the skin, mucociliary phenotype of the airways, and polarization of the intestinal epithelium. More physiological skin, airway and intestinal tissue models based on the BioVaSc® facilitate the in vitro generation of human barrier models that might help to gain more predictable and reliable data in pre-clinical research for drugs, biologicals and vaccines and represent a useful tool to reduce, refine and replace animal studies.