Search

Corneal pathologies from infectious or noninfectious origin have a significant impact on the daily lives of millions of people worldwide. Despite the risk of organ rejection or infection, corneal transplantation is currently the only effective treatment. Finding safe and innovative strategies is the main goal of tissue-engineering-based approaches. In this study, the potential of gelatin methacryloyl (GelMA) hydrogels produced from marine-derived gelatin and loaded with ascorbic acid (as an enhancer of the biological activity of cells) was evaluated for corneal stromal applications. Marine GelMA was synthesized with a methacrylation degree of 75%, enabling effective photocrosslinking, and hydrogels with or without ascorbic acid were produced, encompassing human keratocytes. All the produced formulations exhibited excellent optical and swelling properties with easy handling as well as structural stability and adequate degradation rates that may allow proper extracellular matrix remodeling by corneal stromal cells. Formulations loaded with 0.5 mg/mL of ascorbic acid enhanced the biological performance of keratocytes and induced collagen production. These results suggest that, in addition to marine-derived gelatin being suitable for the synthesis of GelMA, the hydrogels produced are promising biomaterials for corneal regeneration applications

The host immunologic response to a specific material is a critical aspect when considering it for clinical implementation. Collagen and gelatin extracted from marine sources have been proposed as biomaterials for tissue engineering applications, but there is a lack of information in the literature about their immunogenicity. In this work, we evaluated the immune response to collagen and/or gelatin from blue shark and codfish, previously extracted and characterized. After endotoxin evaluation, bone marrow-derived macrophages were exposed to the materials and a panel of pro- and anti-inflammatory cytokines were evaluated both for protein quantification and gene expression. Then, the impact of those materials in the host was evaluated through peritoneal injection in C57BL/6 mice. The results suggested shark collagen as the less immunogenic material, inducing low expression of pro-inflammatory cytokines as well as inducible nitric oxide synthase (encoded by Nos2) and high expression of Arginase 1 (encoded by Arg1). Although shark gelatin appeared to be the material with higher pro-inflammatory expression, it also presents a high expression of IL-10 (anti-inflammatory cytokine) and Arginase (both markers for M2-like macrophages). When injected in the peritoneal cavity of mice, our materials demonstrated a transient recruitment of neutrophil, being almost non-existent after 24 hours of injection. Based on these findings, the studied collagenous materials can be considered interesting biomaterial candidates for regenerative medicine as they may induce an activation of the M2-like macrophage population, which is involved in suppressing the inflammatory processes promoting tissue remodeling

The use of alternative sources for gelatin extraction is in demand in today's industries. Fish skins are an economical and sustainable source option. However, there is a lack of information about the preservation state of skins (fresh, frozen, salted, etc.) and how that affects the gelatin yield and properties, and therefore, compromise the final product. In this study we present a comparative analysis between different reported gelatin extraction processes for fresh and salted codfish (Gadus morhua) skins. The extracted products were characterized based on yield of extraction, amino acid composition, molecular weight distribution, rheological properties and gel strength, as well as the cell compatibility of the gelatins envisaging future biomedical applications. Results showed that extraction method affected the yield and gelatin properties within the same type of fish skin. Thus, it was found that water acidification step, demonstrated higher extraction yield, while other methods produced gelatins rich in OH-proline + proline, promoting enhanced gel strength and rheological properties. There is thus a compromise between yield and gelatin properties that industries need to understand before selecting their gelatin extraction method. Results, also showed that gelatins derived from salted skins demonstrated lower viscoelastic properties and gel strength, when compared with gelatins from fresh skins. Our research represents a unique comparative compilation of different extraction methods in cod skins differently conserved, as a tool on the quest for the sustainable valorization of fish by-products, included in a circular economy framework

Gelatin is generally known as the product derived from thermal denaturation of collagen given origin to an unfolding and cleavage of the triple helix resulting in a polydisperse mixture of polymers [1]. Due to the similarities with collagen, it has been widely used in tissue engineering applications to produce new biomaterials or as cellular carrier [1,2]. The primary sources of gelatins are from mammal origin, yet by-products of the fishery industry have also been considered as raw materials for gelatin production [3]. Different extraction processes are described in literature to obtain gelatins from fish skins, however there is a lack of information about the preservation of those skins (fresh, frozen, salted, etc.) and how that affects the final yield and properties of gelatin. In this study we present a comparative analysis between gelatins produced from fresh and salted codfish (Gadus morhua) skins using different extraction protocols based on methodologies described in literature. The characterization of the materials was assessed based on yield of extraction, amino acid composition, molecular weight distribution, rheological properties, and gel strength, as well as the cell compatibility of the gelatins envisaging future biomedical application. Methodologies using sulphuric + citric acid during the washing processes and a thermal extraction in water demonstrated to produce gelatins rich in OH-proline + proline, enhanced gel strength and rheological behavior, and with higher melting points. Differences between fresh and salted skins were found, with gelatins derived from salted skins demonstrating lower viscoelastic properties, as well as gel strength, when compared with gelatins from fresh skins. Our research has highlighted the importance of choosing the right protocol according to the final application of the gelatins, as a tool on the quest for the sustainable valorization of fish by-products, included in a blue and circular bioeconomy framework

136P26EVALUATION OF IMMUNE RESPONSE OF MARINE-DERIVED COLLAGEN AND GELATINA. L. Alves1, 2, J. Costa-Gouveia 2, 3, Carmen G. Sotelo 5, J.A. Vázquez 5, R. I. Pérez-Martín 5, E. Torrado 2, 3, R. L. Reis1,2,4, A.G. Castro 2,3T. H. Silva1, 213B’s Research Group, I3Bs –Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco, Guimarães, Portugal; 2ICVS/3B’s –PT Government Associate Laboratory, Braga/Guimarães, Portugal; 3Microbiology and Infection Research Domain, Life and Health Sciences Research Institute, School of Medicine, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; 4The Discoveries Centre for Regenerative and Precision Medicine, Headquarters at University of Minho, Avepark, 4805-017 Barco, Guimarães, Portugal; 5Instituto de Investigaciones Marinas (IIM-CSIC), C/Eduardo Cabello 6, Vigo, Pontevedra, SpainThe main goal of Tissue Engineering and Regenerative Medicine (TERM) is the attempt to replace and/or regenerate a damaged cells, tissue or organs with a well-designed and tissue appropriated material [1]. This replacement can be performed using a combination of biomaterial, cells and biochemical signals but also using the biomaterial per sethat can stimulate and induce the regeneration of host tissue itself [2]. The successfulness of this relies on the host response to the biomaterial, namely, the reaction of immune cells to the implant. A correct understanding of the immune system and how it interacts with the biomaterial in order to promote the remodelling is 137extremely important to the effective tissue regeneration. Marine-derived collagens and gelatines are promising biopolymers to be used as building blocks for the development of biomaterials in the field of TERM. The absence of any religious constraints and risks associated

TissueEngineeringstrategiesseekthedevelopmentofanidealscaffoldthatcanperfectlyreplicatetheextracellularmatrix(ECM)ofthetargetedtissue,givingtocellsthe3Dsupporttheyneedforthebiosynthesisofnewtissuesbybiologicalstimulationonmolecularlevel,i.e.supportcellattachment,proliferation,differentiationandorganization.Toachievethisgoal,electrospinningrisesasaneffectiveapproachtofabricatescaffoldsthatcanmimicECM[1].Throughthecontrolofelectrospinningparametersandpolymerchoice,bothsynthetic(e.g.poly(glycolicacid)(PGA),poly(lactic-co-glycolicacid)(PLGA))andnatural(e.g.collagen,chitosan,keratin),submicron-ornanometre-scalefibrescanbeproduced