title: Development and application of three-dimensional skin equivalents for the investigation of percutaneous worm invasion.
abstract: Investigation of percutaneous helminth infection is generally based on animal models or excised skin. As desirable replacement of animal experiments, tissue-engineered skin equivalents have recently been applied in microbial and viral in vitro infection models. In the present study, the applicability of tissue-engineered skin equivalents for the investigation of percutaneous helminth invasion was evaluated. Epidermal and a full-thickness skin equivalents that suit the requirements for helminth invasion studies were developed. Quantitative invasion assays were performed with the skin-invading larvae of the helminths Strongyloides ratti and Schistosoma mansoni. Both skin equivalents provided a physical barrier to larval invasion of the nematode S. ratti, while these larvae could invade and permeate a cell-free collagen scaffold and ex vivo epidermis. In contrast, the epidermal and full-thickness skin equivalents exhibited a human host-specific susceptibility to larvae of trematode S. mansoni, which could well penetrate. Invasion of S. mansoni in cell-free collagen scaffold was lowest for all experimental conditions. Thus, reconstructed epidermis and full-thickness skin equivalents confirmed a high degree of accordance to native tissue. Additionally, not only tailless schistosomula but also cercariae could permeate the skin equivalents, and thus, delayed tail loss hypothesis was supported. The present study indicates that the limitations in predictive infection test systems for human-pathogenic invading helminths can be overcome by tissue-engineered in vitro skin equivalents allowing a substitution of the human skin for analysis of the interaction between parasites and their hosts' tissues. This novel tissue-engineered technology accomplishes the endeavor to save animal lives.
authors.affiliation: Chair Tissue Engineering and Regenerative Medicine, University Hospital Wuerzburg, Wuerzburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Jannasch
authors.affiliation: Department of Cell and Tissue Engineering, Fraunhofer Institute of Interfacial Engineering and Biotechnology (IGB), Stuttgart, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Groeber
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
authors.forename: N W
authors.initials: NW
authors.lastname: Brattig
authors.affiliation: Institute of Tropical Medicine, University Hospital Tuebingen, Tuebingen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Unger
authors.affiliation: Chair Tissue Engineering and Regenerative Medicine, University Hospital Wuerzburg, Wuerzburg, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Walles
authors.affiliation: Chair Tissue Engineering and Regenerative Medicine, University Hospital Wuerzburg, Wuerzburg, Germany. Electronic address: Jan.Hansmann@uni-wuerzburg.de.
authors.forename: J
authors.initials: J
authors.lastname: Hansmann
mesh_terms: D000818:Animals; D001700:Biomphalaria / Q000469:parasitology; D002478:Cells, Cultured; D000078404:Epidermal Cells; D005243:Feces / Q000469:parasitology; D005347:Fibroblasts / Q000166:cytology / Q000469:parasitology; D052816:Foreskin / Q000166:cytology; D006801:Humans; D007583:Jejunum / Q000166:cytology; D015603:Keratinocytes / Q000166:cytology / Q000469:parasitology; D008297:Male; D008954:Models, Biological; D051381:Rats; D017208:Rats, Wistar; D012550:Schistosoma mansoni / Q000502:physiology*; D012867:Skin / Q000469:parasitology*; D017170:Strongyloides ratti / Q000502:physiology*; D013552:Swine
keywords: Human skin equivalents; Quantitative invasion assay; Schistosoma mansoni; Strongyloides ratti; Tissue engineering