Organ in vitro synthesis is one of the last bottlenecks between tissue engineering and transplantation of synthetic organs. Bioprinting has proven its capacity to produce 3D objects composed of living cells but highly organized tissues such as full thickness skin (dermis + epidermis) are rarely attained. The focus of the present study is to demonstrate the capability of a newly developed ink formulation and the use of an open source printer, for the production of a really complete skin model. Proofs are given through immunostaining and electronic microscopy that the bioprinted skin presents all characteristics of human skin, both at the molecular and macromolecular level. Finally, the printability of large skin objects is demonstrated with the printing of an adult-size ear.
Objective Intrinsic skin ageing is mainly caused by cellular senescence. p16 and p21 are two important tumour suppressor proteins that play essential roles during cell proliferation and ageing through regulating the expression of several genes. Moreover, physical changes between the ages of 55 and 60 years affect one's physical and disrupt self‐esteem. The cosmetics industry has focused on bioactive substances derived from natural products such as plants, mushrooms and marine algae to counteract the deleterious effect on skin senescence. Besides these products, compounds produced by bacteria may decelerate individual senescence. Methods In order to evaluate the potential benefits of bacteria extract over skin ageing, we investigated whether a Sphingomonas hydrophobicum (SH) extract is able to protect our skin against senescence mechanisms. We used an ageing full‐thickness skin equivalent model, which was treated or not with the bacteria extract in a systemic way for 42 days. p21 and p16 and senescence‐associated galactosidase activity were used to detect cellular senescence with immunohistology. Using a psychobiological approach, we evaluated in vivo the effect of SH extract on self‐esteem, isotropy and suppleness. Results Sphingomonas extract significantly suppressed senescence associated with β‐galactosidase activation. It also significantly inhibited the expression of cell cycle inhibitors (p21 and p16). At the same time, the bacteria extract has a significant positive impact on the issue by increasing the expression of versican and fibrillin‐1. Significant improvements of self‐esteem were reported after 56 days of SH extract application. These psychological benefits were accompanied by a significant improvement in skin suppleness and isotropy. Conclusion Sphingomonas extract delays intrinsic skin ageing process by inhibiting cellular senescence, and has also the capability to restructure the skin. These beneficial physiological effects induced by SH extract have a positive influence on self‐esteem. Because skin ageing causes emotional distress, SH extract can serve as an anti‐ageing cosmeceutical agent and help to build a better psychological health, and help individuals to assume ageing.
Background: Intraoperative three-dimensional fabrication of living tissues could be the next biomedical revolution in patient treatment. Approach: We developed a surgery-ready robotic three-dimensional bioprinter and demonstrated that a bioprinting procedure using medical grade hydrogel could be performed using a 6-axis robotic arm in vivo for treating burn injuries. Results: We conducted a pilot swine animal study on a deep third-degree severe burn model. We observed that the use of cell-laden bioink as treatment substantially affects skin regeneration, producing in situ fibroblast growth factor and vascular endothelial growth factor, necessary for tissue regeneration and re-epidermalization of the wound. Conclusions:We described an animal study of intraoperative three-dimensional bioprinting living tissue. This emerging technology brings the first proof of in vivo skin printing feasibility using a surgery-ready robotic arm-based bioprinter. Our positive outcome in skin regeneration, joined with this procedure's feasibility, allow us to envision the possibility of using this innovative approach in a human clinical trial in the near future.
Clinical grade cultured epithelial autograft (CEA) are routinely used to treat burns covering more than 60% of the total body surface area. However, although the epidermis may be efficiently repaired by CEA, the dermal layer, which is not spared in deep burns, requires additional treatment strategies. Our aim is to develop an innovative method of skin regeneration based on in situ 3D bioprinting of freshly isolated autologous skin cells. We describe herein bioink formulation and cell preparation steps together with experimental data validating a straightforward enzyme‐free protocol of skin cell extraction. This procedure complies with both the specific needs of 3D bioprinting process and the stringent rules of good manufacturing practices. This mechanical extraction protocol, starting from human skin biopsies, allows harvesting a sufficient amount of both viable and growing keratinocytes and fibroblasts. We demonstrated that a dermis may be reconstituted in vitro starting from a medical grade bioink and mechanically extracted skin cells. In these experiments, proliferation of the extracted cells can be observed over the first 21 days period after 3D bioprinting and the analysis of type I collagen exhibited a de novo production of extracellular matrix proteins. Finally, in vivo experiments in a murine model of severe burn provided evidences that a topical application of our medical grade bioink was feasible and well‐tolerated. Overall, these results represent a valuable groundwork for the design of future 3D bioprinting tissue engineering strategies aimed at treating, in a single intraoperative step, patients suffering from extended severe burns.
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