Agradecimentos: The authors acknowledge Prof. Dr Joaquim Murray Bustorff-Silva of the Department of Surgery (University of Campinas) for the critical reading of this article and to Prof. Dr José Vassallo of the Department of Pathological Anatomy (University of Campinas) for the histopathological analysis support. Also to the residents of the Department of Thoracic Surgery (University of Campinas) and to Miss Krissia Caroline Leme (University of Campinas) for the viability analysis support. Finally, the authors thank the staff of the Life Sciences Core Facility (LaCTAD) from the University of Campinas (UNICAMP) for the Cell Biology analysis. This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq-Brazil, Grant No. 421745/2016-9). Bruna Maria Manzini expresses thanks for the PhD scholarship No. 02-P-4569/2018 from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES-Brazil) Ver menos

Abstract: Tracheal fistula (TF) treatments may involve temporary orthosis and further ablative procedures, which can lead to infection. Thus, TF requires other therapy alternatives development. The hypothesis of this work was to demonstrate the feasibility of a tissue-engineered alternative for small TF in a preclinical model. Also, its association with suture filaments enriched with adipose tissue-derived mesenchymal stromal stem cells (AT-MSCs) was assessed to determine whether it could optimize the regenerative process. Poly (L-Lactic acid) (PLLA) membranes were manufactured by electrospinning and had morphology analyzed by scanning electron microscopy. AT-MSCs were cultured in these scaffolds and in vitro assays were performed (cytotoxicity, cellular adhesion, and viability). Subsequently, these cellular constructs were implanted in an animal small TF model. The association with suture filaments containing attached AT-MSCs was present in one animal group. After 30 d, animals were sacrificed and regenerative potential was evaluated, mainly related to the extracellular matrix remodeling, by performing histopathological (Hematoxylin-Eosin and trichrome Masson) and immunohistochemistry (Collagen I/II/III, matrix metalloproteinases-2, matrix metalloproteinases-9, vascular endothelial growth factor, and interleukin-10) analyses. PLLA membranes presented porous fibers, randomly oriented. In vitro assays results showed that AT-MSCs attached were viable and maintained an active metabolism. Swine implanted with AT-MSCs attached to membranes and suture filaments showed aligned collagen fibers and a better regenerative progress in 30 d CONCLUSIONS: PLLA membranes with AT-MSCs attached were useful to the extracellular matrix restoration and have a high potential for small TF treatment. Also, their association with suture filaments enriched with AT-MSCs was advantageous Ver menos