3D in vitro models of skeletal muscle: myopshere, myobundle and bioprinted muscle construct.

Typical two-dimensional (2D) culture models of skeletal muscle-derived cells cannot fully recapitulate the organization and function of living muscle tissues, restricting their usefulness in in-depth physiological studies. The development of functional 3D culture models offers a major opportunity to mimic the living tissues and to model muscle diseases. In this respect, this new type of in vitro model significantly increases our understanding of the involvement of the different cell types present in the formation of skeletal muscle and their interactions, as well as the modalities of response of a pathological muscle to new therapies. This second point could lead to the identification of effective treatments. Here, we report the significant progresses that have been made the last years to engineer muscle tissue-like structures, providing useful tools to investigate the behavior of resident cells. Specifically, we interest in the development of myopshere- and myobundle-based systems as well as the bioprinting constructs. The electrical/mechanical stimulation protocols and the co-culture systems developed to improve tissue maturation process and functionalities are presented. The formation of these biomimetic engineered muscle tissues represents a new platform to study skeletal muscle function and spatial organization in large number of physiological and pathological contexts.

Bioimpressão e produção de mini-órgãos com células tronco / Bioprinting with stem cells and production of mini-organs

A bioimpressão é considerada uma fonte promissora no desenvolvimento celular, e na produção de mini-órgãos, válulas, cartilagens que futuramente poderão ser utilizados na terapia para transplantes em animais e humanos. Assim, essa técnica poderá ser utilizada como uma terapia eletiva, no tratamento de injúrias e principalmente no tratamento de doenças crônico-degenerativas. Em humanos essa terapia está sendo pesquisada a fim de auxiliar a medicina no tratamento e regeneração de tecidos impressos a partir de arcabouços de células desenvolvidas a partir de células-tronco, biomateriais e impressões em 3D. O uso dessa tecnologia é também um auxiliar nas pesquisas oncológicas com o intuito de projetar e avaliar a proliferação celular de tumores, bem como a ação de novos medicamentos quimioterápicos. No entanto, a maior limitação para o uso da terapia utilizando-se a impressora de células, órgãos e tecidos em 3D é a falta de protocolos unificados com metodologias reprodutíveis e detalhadas; com o objetivo de viabilizar a utilização da impressora e a impressão de células, órgãos e tecidos em 3D. Dessa forma, esta revisão busca reunir as publicações mais atuais na área, as quais destacam os avanços no uso de bioimpressão com células-tronco, a fim de descrever as principais técnicas e os potenciais de utilização como alternativa terapêutica na medicina humana e veterinária.(AU)

The bioprinting is considered a promising source in cell development, and production of mini-organs, valves, cartilage that may eventually be used in therapy for transplantation in animals and humans. It can also be used as an elective therapy in the treatment of injuries and treatment of chronic degenerative diseases. In humans, this therapy is been studied mainly in the treatment and regeneration of tissues printed from scaffold cells developed from stem cells, biomaterials and impressions in 3D. This technology is also an aid for the study of the formation of tumors, in order to design and evaluate the cellular proliferation of the tumors and the action of new chemotherapy drugs. However, the main drawback to this therapy is the lack of standardized protocols with reproducible and detailed methodologies with the aim of enabling the use of bioprinting and printing cells, tissues and organs in 3D. Thus, this review seeks to bring together the most current publications of the bioprinting area in order to describe the technique and its potential use as a therapeutic alternative.(AU)