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.

Photocrosslinkable Gelatin Hydrogel for Epidermal Tissue Engineering

“…The unique combination of photo-polymerizability, optimal mechanical properties, biodegradability and biocompatibility make GelMA a promising material for skin tissue engineering. [22] Such exceptional characteristic of GelMA also distinct them from other reported substrates to reconstruct epidermis including polycarbonate membrane [52] or decellularized porcine intestine [53] which cannot be tailor made according to the patient's own wounds and whose physical and chemical properties cannot be readily modified. We anticipate that the developed GelMA hydrogel could find applications as epidermal substitutes, wound dressings or substrate to construct in vitro skin models.…”

In Vivo‐Like Culture Conditions in a Bioreactor Facilitate Improved Tissue Quality in Corneal Storage

“…Except for the biochrom medium 1, all media were supplemented with 1% Gentamicin (Genaxxon bioscience GmbH, Ulm, Germany) and 1% Penicillin/Streptomycin as well as 1% Amphotericin B (Gibco™, Thermo Fisher Scientific, Waltham, USA). Corneal tissues were stored in standard submerse culture and in cell crowns at 37 °C, 5% CO 2 and 95% humidity for 7 days. For the dynamic culture, the bioreactor was operated at 37 °C and 5% CO 2 .…”

Advances in the Molecular and Cellular Biology of Strongyloides spp.

“…Skin samples used in such PERL chambers can constitute a source of technical variation due to their species of origin, thickness, inclusion of subcutaneous fat, storage parameters (frozen or fresh), and other factors that are difficult to control. In view of this, the achievement of an engineered three-dimensional skin equivalent culture, derived entirely from continuous lines of component cells [74], represents a very significant advancement in the study of percutaneously invasive larvae of parasitic helminths. In this instance, S. ratti iL3 were unable to penetrate the full-thickness skin equivalent structures but could traverse a cell-free collagen scaffold.…”