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The efficacy of skin substitutes is established for the treatment of burn injuries, but its use is not limited to this condition. This technology has the potential to improve the treatment of various conditions by offering highly advanced and personalized treatments. In vivo studies are challenging but essential to move to clinical use in humans. Mice are the most widely used species in preclinical studies, but the main drawback of this model is the limited surface area of the graft in long-term transplantation studies caused by the displacement and the contraction of the graft. We improved the conventional surgical procedures by stabilizing the chamber covering the graft with intramuscular sutures and by adding a tie-over bolster dressing. The current study was therefore performed to compare outcomes of skin grafts between the conventional and optimized skin graft model. Human self-assembled skin substitutes (SASSs) were prepared and grafted to athymic mice either by the conventional method or by the new grafting method. Graft healing and complications were assessed using digital photographs on postoperative days 7, 14, and 21. Similar structure and organization were observed by histological staining. The new grafting method reduced medium and large displacement events by 1.26-fold and medium and large contraction events by 1.8-fold, leading to a 1.6-fold increase in graft surface area compared to skin substitutes grafted with the usual method. This innovation ensures better reproducibility and consistency of skin substitute transplants on mice.

In our experience, keratinocytes cultured in feeder-free conditions and in commercially available defined and serum-free media cannot be as efficiently massively expanded as their counterparts grown in conventional bovine serum-containing medium, nor can they properly form a stratified epidermis in a skin substitute model. We thus tested a new chemically defined serum-free medium, which we developed for massive human primary keratinocyte expansion and skin substitute production. Our medium, named Surge Serum-Free Medium (Surge SFM), was developed to be used alongside a feeder layer. It supports the growth of keratinocytes freshly isolated from a skin biopsy and cryopreserved primary keratinocytes in cultured monolayers over multiple passages. We also show that keratin-19-positive epithelial stem cells are retained through serial passaging in Surge SFM cultures. Transcriptomic analyses suggest that gene expression is similar between keratinocytes cultured with either Surge SFM or the conventional serum-containing medium. Additionally, Surge SFM can be used to produce bilayered self-assembled skin substitutes histologically similar to those produced using serum-containing medium. Furthermore, these substitutes were grafted onto athymic mice and persisted for up to six months. In conclusion, our new chemically defined serum-free keratinocyte culture medium shows great promise for basic research and clinical applications.

OBJECTIVES: Food security intervention is particularly complex in rural areas. The local stakeholders of the regional county municipality (RCM) of Portneuf wished to analyze the regional food supply in order to reduce food insecurity. The objective of this study was to characterize the RCM’s food environment and to identify potential food deserts and priority intervention areas. METHOD: We measured the quality of the food supply in the RCM’s food stores, using four indicators: freshness, diversity, economic accessibility and relative availability. We mapped the distance between residences and the nearest food store with a favourable result for all four indices to locate potential food deserts. We then presented the mapping of the food environment to a group of local stakeholders and compared it to their own perception. RESULTS: This study reveals three sectors that meet the criteria of a food desert in the RCM. Local actors did not perceive these sectors as food deserts, but thought they were at risk of becoming such in the future. We complemented the measures by taking into account the structuring impact of certain infrastructures as well as the temporal and seasonal accessibility of food stores in rural areas. Only one priority intervention area was suggested. CONCLUSION: Presenting geographical analyses to local stakeholders improved the characterization of the studied food environment. The use of a mixed methodology has enabled the particularities of the rural environment to be better accounted for and has facilitated intersectoral mobilization around food insecurity at the regional level. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.17269/s41997-019-00239-8) contains supplementary material, which is available to authorized users.

Urinary tract is subjected to many varieties of pathologies since birth including congenital anomalies, trauma, inflammatory lesions, and malignancy. These diseases necessitate the replacement of involved organs and tissues. Shortage of organ donation, problems of immunosuppression, and complications associated with the use of nonnative tissues have urged clinicians and scientists to investigate new therapies, namely, tissue engineering. Tissue engineering follows principles of cell transplantation, materials science, and engineering. Epithelial and muscle cells can be harvested and used for reconstruction of the engineered grafts. These cells must be delivered in a well-organized and differentiated condition because water-seal epithelium and well-oriented muscle layer are needed for proper function of the substitute tissues. Synthetic or natural scaffolds have been used for engineering lower urinary tract. Harnessing autologous cells to produce their own matrix and form scaffolds is a new strategy for engineering bladder and urethra. This self-assembly technique avoids the biosafety and immunological reactions related to the use of biodegradable scaffolds. Autologous equivalents have already been produced for pigs (bladder) and human (urethra and bladder). The purpose of this paper is to present a review for the existing methods of engineering bladder and urethra and to point toward perspectives for their replacement.

Current urethral reconstruction procedures present many related complications. Moreover, the availability of urologic tissue is limited. Free of exogenous biomaterials, synthetic polymers or acellular matrices, a new tissue engineering technology has been optimized. This technique is known as self-assembly. The fibroblasts produce and assemble their own extracellular matrix to form a tissue very similar to native one. Goals are: to reconstruct a human urethral substitute containing a mature urothelium and a functional vascular network. The same substitute will also be produced using rabbit cells to allow autologous in vivo grafting.