Marine collagen scaffolds for nasal cartilage repair: prevention of nasal septal perforations in a new orthotopic rat model using tissue engineering techniques

Tissue Engineering and Regenerative Medicine in the Field of Otorhinolaryngology

BACKGROUND

Otorhinolaryngology is a medical specialty that focuses on the clinical study and treatments of diseases within head and neck regions, specifically including the ear, nose, and throat (ENT), but excluding eyes and brain. These anatomical structures play significant roles in a person's daily life, including eating, speaking as well as facial appearance and expression, thus greatly impacting one's overall satisfaction and quality of life. Consequently, injuries to these regions can significantly impact a person's well-being, leading to extensive research in the field of tissue engineering and regenerative medicine over many years.

METHODS

This chapter provides an overview of the anatomical characteristics of otorhinolaryngologic tissues and explores the tissue engineering and regenerative medicine research in otology (ear), rhinology (nose), facial bone, larynx, and trachea.

RESULTS AND CONCLUSION

The integration of tissue engineering and regenerative medicine in otorhinolaryngology holds the promise of broadening the therapeutic choices for a wide range of conditions, ultimately improving quality of a patient's life.

Achieving Nasal Septal Cartilage In Situ Regeneration: Focus on Cartilage Progenitor Cells

The nasal septal cartilage plays an important role in preventing the collapse of the nasal bones and maintaining the appearance of the nose. In the context of inherent difficulties regarding septal cartilage repair and the shortage of cartilage graft resources for regeneration, tissue engineering, especially the in situ strategy based on scaffolds, has become a new prospect and become one of the most promising approaches. Given that it is difficult for chondrocytes to achieve directional migration and secrete matrix components to participate in tissue repair after cartilage injury, cartilage progenitor cells (CPCs), with great migratory ability and stem cell characteristics, have caught the attention of researchers and brought hope for nasal septal cartilage in situ regeneration. In this review, we first summarized the distribution, characteristics, isolation, and culture methods of nasal septal CPCs. Subsequently, we described the roles of migratory CPCs in cartilage regeneration. Finally, we reviewed the existing studies on CPCs-based cartilage tissue engineering and summarized the strategies for promoting the migration and chondrogenesis of CPCs so as to provide ideas for achieving nasal septal cartilage in situ regeneration.

Cutting Edge Aquatic-Based Collagens in Tissue Engineering

Aquatic-based collagens have attracted much interest due to their great potential application for biomedical sectors, including the tissue engineering sector, as a major component of the extracellular matrix in humans. Their physical and biochemical characteristics offer advantages over mammalian-based collagen; for example, they have excellent biocompatibility and biodegradability, are easy to extract, and pose a relatively low immunological risk to mammalian products. The utilization of aquatic-based collagen also has fewer religious restrictions and lower production costs. Aquatic-based collagen also creates high-added value and good environmental sustainability by aquatic waste utilization. Thus, this study aims to overview aquatic collagen's characteristics, extraction, and fabrication. It also highlights its potential application for tissue engineering and the regeneration of bone, cartilage, dental, skin, and vascular tissue. Moreover, this review highlights the recent research in aquatic collagen, future prospects, and challenges for it as an alternative biomaterial for tissue engineering and regenerative medicines.

Characterization of the Biophysical Properties and Cell Adhesion Interactions of Marine Invertebrate Collagen from Rhizostoma pulmo

Collagen is the most ubiquitous biomacromolecule found in the animal kingdom and is commonly used as a biomaterial in regenerative medicine therapies and biomedical research. The collagens used in these applications are typically derived from mammalian sources which poses sociological issues due to widespread religious constraints, rising ethical concern over animal rights and the continuous risk of zoonotic disease transmission. These issues have led to increasing research into alternative collagen sources, of which marine collagens, in particular from jellyfish, have emerged as a promising resource. This study provides a characterization of the biophysical properties and cell adhesion interactions of collagen derived from the jellyfish Rhizostoma pulmo (JCol). Circular dichroism spectroscopy and atomic force microscopy were used to observe the triple-helical conformation and fibrillar morphology of JCol. Heparin-affinity chromatography was also used to demonstrate the ability of JCol to bind to immobilized heparin. Cell adhesion assays using integrin blocking antibodies and HT-1080 human fibrosarcoma cells revealed that adhesion to JCol is primarily performed via β1 integrins, with the exception of α2β1 integrin. It was also shown that heparan sulfate binding plays a much greater role in fibroblast and mesenchymal stromal cell adhesion to JCol than for type I mammalian collagen (rat tail collagen). Overall, this study highlights the similarities and differences between collagens from mammalian and jellyfish origins, which should be considered when utilizing alternative collagen sources for biomedical research.

Alternative lung cell model systems for toxicology testing strategies: Current knowledge and future outlook

Due to the current relevance of pulmonary toxicology (with focus upon air pollution and the inhalation of hazardous materials), it is important to further develop and implement physiologically relevant models of the entire respiratory tract. Lung model development has the aim to create human relevant systems that may replace animal use whilst balancing cost, laborious nature and regulatory ambition. There is an imperative need to move away from rodent models and implement models that mimic the holistic characteristics important in lung function. The purpose of this review is therefore, to describe and identify the various alternative models that are being applied towards assessing the pulmonary toxicology of inhaled substances, as well as the current and potential developments of various advanced models and how they may be applied towards toxicology testing strategies. These models aim to mimic various regions of the lung, as well as implementing different exposure methods with the addition of various physiologically relevent conditions (such as fluid-flow and dynamic movement). There is further progress in the type of models used with focus on the development of lung-on-a-chip technologies and bioprinting, as well as and the optimization of such models to fill current knowledge gaps within toxicology.

Mechanically Enhanced Salmo salar Gelatin by Enzymatic Cross-linking: Premise of a Bioinspired Material for Food Packaging, Cosmetics, and Biomedical Applications

Marine animal by-products of the food industry are a great source of valuable biomolecules. Skins and bones are rich in collagen, a protein with various applications in food, cosmetic, healthcare, and medical industries in its native form or partially hydrolyzed (gelatin). Salmon gelatin is a candidate of interest due to its high biomass production available through salmon consumption, its biodegradability, and its high biocompatibility. However, its low mechanical and thermal properties can be an obstacle for various applications requiring cohesive material. Thus, gelatin modification by cross-linking is necessary. Enzymatic cross-linking by microbial transglutaminase (MTG) is preferred to chemical cross-linking to avoid the formation of potentially cytotoxic residues. In this work, the potential of salmon skin gelatin was investigated, in a comparative study with porcine gelatin, and an enzymatic versus chemical cross-linking analysis. For this purpose, the two cross-linking methods were applied to produce three-dimensional, porous, and mechanically reinforced hydrogels and sponges with different MTG ratios (2%, 5%, and 10% w/w gelatin). Their biochemical, rheological, and structural properties were characterized, as well as the stability of the material, including the degree of syneresis and the water-binding capacity. The results showed that gelatin enzymatically cross-linked produced material with high cross-linking densities over 70% of free amines. The MTG addition seemed to play a crucial role, as shown by the increase in mechanical and thermal resistances with the production of a cohesive material stable above 40 °C for at least 7 days and comparable to porcine and chemically cross-linked gelatins. Two prototypes were obtained with similar thermal resistances but different microstructures and viscoelastic properties, due to different formation dynamics of the covalent network. Considering these results, the enzymatically cross-linked salmon gelatin is a relevant candidate as a biopolymer for the production of matrix for a wide range of biotechnological applications such as food packaging, cosmetic patch, wound healing dressing, or tissue substitute.

Characteristics of Marine Biomaterials and Their Applications in Biomedicine

Oceans have vast potential to develop high-value bioactive substances and biomaterials. In the past decades, many biomaterials have come from marine organisms, but due to the wide variety of organisms living in the oceans, the great diversity of marine-derived materials remains explored. The marine biomaterials that have been found and studied have excellent biological activity, unique chemical structure, good biocompatibility, low toxicity, and suitable degradation, and can be used as attractive tissue material engineering and regenerative medicine applications. In this review, we give an overview of the extraction and processing methods and chemical and biological characteristics of common marine polysaccharides and proteins. This review also briefly explains their important applications in anticancer, antiviral, drug delivery, tissue engineering, and other fields.

Application of artificial neural networks to predict Young's moduli of cartilage scaffolds: An in-vitro and micromechanical study

In this study, four-phase Gelatin-Polypyrrole-Akermanite-Magnetite scaffolds were fabricated and analyzed using in-vitro tests and numerical simulations. Such scaffolds contained various amounts of Magnetite bioceramics as much as 0, 5, 10, and 15 wt% of Gelatin-Polypyrrole-Akermanite biocomposite. X-ray diffraction analysis and Fourier transform infrared spectroscopy were conducted. Swelling and degradation of the scaffolds were studied by immersing them in phosphate-buffered saline, PBS, solution. Magnetite bioceramics decreased the swelling percent and degradation duration. By immersing scaffolds in simulated body fluid, the highest formation rate of Apatite was observed in the 15 wt% Magnetite samples. The mean pore size was in an acceptable range to provide suitable conditions for cell proliferation. MG-63 cells were cultured on extracts of the scaffolds for 24, 48, and 72 h and their surfaces for 24 h. Cell viabilities and cell morphologies were assessed. Afterward, micromechanical models with spherical and polyhedral voids and artificial neural networks were employed to predict Young's moduli of the scaffolds. Based on the results of finite element analyses, spherical-shaped void models made the best predictions of elastic behavior in the 0, 5 wt% Magnetite scaffolds compared to the experimental data. Results of the simulations and experimental tests for the ten wt% Magnetite samples were well matched in both micromechanical models. In the 15 wt% Magnetite sample, models with polyhedral voids could precisely predict Young's modulus of such scaffolds.

Progress of 3D Printing Techniques for Nasal Cartilage Regeneration

Once cartilage is damaged, its self-repair capacity is very limited. The strategy of tissue engineering has brought a new idea for repairing cartilage defect and cartilage regeneration. In particular, nasal cartilage regeneration is a challenge because of the steady increase in nasal reconstruction after oncologic resection, trauma, or rhinoplasty. From this perspective, three-dimensional (3D) printing has emerged as a promising technology to address the complexity of nasal cartilage regeneration, using patient's image data and computer-aided deposition of cells and biomaterials to precisely fabricate complex, personalized tissue-engineered constructs. In this review, we summarized the major progress of three prevalent 3D printing approaches, including inkjet-based printing, extrusion-based printing and laser-assisted printing. Examples are highlighted to illustrate 3D printing for nasal cartilage regeneration, with special focus on the selection of seeded cell, scaffolds and growth factors. The purpose of this paper is to systematically review recent research about the challenges and progress and look forward to the future of 3D printing techniques for nasal cartilage regeneration.Level of Evidence III This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors https://www.springer.com/00266 .

In vivo efficacy of 3D-printed elastin-gelatin-hyaluronic acid scaffolds for regeneration of nasal septal cartilage defects

Nasal septal cartilage perforations occur due to the different pathologies. Limited healing ability of cartilage results in remaining defects and further complications. This study sought to assess the efficacy of elastin-gelatin-hyaluronic acid (EGH) scaffolds for regeneration of nasal septal cartilage defects in rabbits. Defects (4 × 7 mm) were created in the nasal septal cartilage of 24 New Zealand rabbits. They were randomly divided into four groups: Group 1 was the control group with no further intervention, Group 2 received EGH scaffolds implanted in the defects, Group 3 received EGH scaffolds seeded with autologous auricular chondrocytes implanted in the defects, and Group 4 received EGH scaffolds seeded with homologous auricular chondrocytes implanted in the defects. After a 4-month healing period, computed tomography (CT) and magnetic resonance imaging (MRI) scans were obtained from the nasal septal cartilage, followed by histological evaluations of new tissue formation. Maximum regeneration occurred in Group 2, according to CT, and Group 3, according to both T1 and T2 images with 7.68 ± 1.36, 5.44 ± 2.41, and 8.72 ± 3.02 mm2 defect area respectively after healing. The difference in the defect size was statistically significant after healing between the experimental groups. Group 3 showed significantly greater regeneration according to CT scans and T1 and T2 images. The neocartilage formed over the underlying old cartilage with no distinct margin in histological evaluation. The EGH scaffolds have the capability of regeneration of nasal cartilage defects and are able to integrate with the existing cartilage; yet, they present the best results when pre-seeded with autologous chondrocytes.

Marine origin materials on biomaterials and advanced therapies to cartilage tissue engineering and regenerative medicine

The body's self-repair capacity is limited, including injuries on articular cartilage zones. Over the past few decades, tissue engineering and regenerative medicine (TERM) has focused its studies on the development of natural biomaterials for clinical applications aiming to overcome this self-therapeutic bottleneck. This review focuses on the development of these biomaterials using compounds and materials from marine sources that are able to be produced in a sustainable way, as an alternative to mammal sources (e.g., collagens) and benefiting from their biological properties, such as biocompatibility, low antigenicity, biodegradability, among others. The structure and composition of the new biomaterials require mimicking the native extracellular matrix (ECM) of articular cartilage tissue. To design an ideal temporary tissue-scaffold, it needs to provide a suitable environment for cell growth (cell attachment, proliferation, and differentiation), towards the regeneration of the damaged tissues. Overall, the purpose of this review is to summarize various marine sources to be used in the development of different tissue-scaffolds with the capability to sustain cells envisaging cartilage tissue engineering, analysing the systems displaying more promising performance, while pointing out current limitations and steps to be given in the near future.

Marine-Derived Collagen as Biomaterials for Human Health

Collagen is a kind of biocompatible protein material, which is widely used in medical tissue engineering, drug delivery, cosmetics, food and other fields. Because of its wide source, low extraction cost and good physical and chemical properties, it has attracted the attention of many researchers in recent years. However, the application of collagen derived from terrestrial organisms is limited due to the existence of diseases, religious beliefs and other problems. Therefore, exploring a wider range of sources of collagen has become one of the main topics for researchers. Marine-derived collagen (MDC) stands out because it comes from a variety of sources and avoids issues such as religion. On the one hand, this paper summarized the sources, extraction methods and characteristics of MDC, and on the other hand, it summarized the application of MDC in the above fields. And on the basis of the review, we found that MDC can not only be extracted from marine organisms, but also from the wastes of some marine organisms, such as fish scales. This makes further use of seafood resources and increases the application prospect of MDC.

Jellyfish Collagen: A Biocompatible Collagen Source for 3D Scaffold Fabrication and Enhanced Chondrogenicity

Osteoarthritis (OA) is a multifactorial disease leading to degeneration of articular cartilage, causing morbidity in approximately 8.5 million of the UK population. As the dense extracellular matrix of articular cartilage is primarily composed of collagen, cartilage repair strategies have exploited the biocompatibility and mechanical strength of bovine and porcine collagen to produce robust scaffolds for procedures such as matrix-induced chondrocyte implantation (MACI). However, mammalian sourced collagens pose safety risks such as bovine spongiform encephalopathy, transmissible spongiform encephalopathy and possible transmission of viral vectors. This study characterised a non-mammalian jellyfish (Rhizostoma pulmo) collagen as an alternative, safer source in scaffold production for clinical use. Jellyfish collagen demonstrated comparable scaffold structural properties and stability when compared to mammalian collagen. Jellyfish collagen also displayed comparable immunogenic responses (platelet and leukocyte activation/cell death) and cytokine release profile in comparison to mammalian collagen in vitro. Further histological analysis of jellyfish collagen revealed bovine chondroprogenitor cell invasion and proliferation in the scaffold structures, where the scaffold supported enhanced chondrogenesis in the presence of TGFβ1. This study highlights the potential of jellyfish collagen as a safe and biocompatible biomaterial for both OA repair and further regenerative medicine applications.

Applications of marine collagens in bone tissue engineering

For decades, collagen has been among the most widely used biomaterials with several biomedical applications. Recently, researchers have shown a keen interest in collagen obtained from marine sources because of its biocompatibility, biodegradability, ease of extractability, safety, low immunogenicity, and low production costs. A wide variety of marine collagen-based scaffolds have been developed for bone tissue engineering, and these scaffolds display excellent biological effects. This review aims to provide an overview of the biological effects of marine collagen in bone engineering, such as promoting osteogenesis and collagen synthesis, inhibiting inflammation, inducing the differentiation of cartilage, and improving bone mineral density. Marine collagen holds great promise as a biomaterial in bone tissue engineering.

Will Tissue-Engineering Strategies Bring New Hope for the Reconstruction of Nasal Septal Cartilage?

The nasal septal cartilage plays an important role in the growth of midface and as a vertical strut preventing the collapse of the nasal bones. The repair of nasal cartilage defects remains a major challenge in reconstructive surgery. The tissue engineering strategy in the development of tissue has opened a new perspective to generate functional tissue for transplantation. Given the poor regenerative properties of cartilage and a limited amount of autologous cartilage availability, intense interest has evoked for tissue engineering approaches for cartilage development to provide better outcomes for patients who require nasal septal reconstruction. Despite numerous attempts to substitute the shapely hyaline cartilage in the nasal cartilages, many significant challenges remained unanswered. The aim of this research was to carry out a critical review of the literature on research work carried out on the development of septal cartilage using a tissue engineering approach, concerning different cell sources, scaffolds and growth factors, as well as its clinical pathway and trials have already been carried out.

From Food Waste to Innovative Biomaterial: Sea Urchin-Derived Collagen for Applications in Skin Regenerative Medicine

Collagen-based skin-like scaffolds (CBSS) are promising alternatives to skin grafts to repair wounds and injuries. In this work, we propose that the common marine invertebrate sea urchin represents a promising and eco-friendly source of native collagen to develop innovative CBSS for skin injury treatment. Sea urchin food waste after gonad removal was here used to extract fibrillar glycosaminoglycan (GAG)-rich collagen to produce bilayer (2D + 3D) CBSS. Microstructure, mechanical stability, permeability to water and proteins, ability to exclude bacteria and act as scaffolding for fibroblasts were evaluated. Our data show that the thin and dense 2D collagen membrane strongly reduces water evaporation (less than 5% of water passes through the membrane after 7 days) and protein diffusion (less than 2% of BSA passes after 7 days), and acts as a barrier against bacterial infiltration (more than 99% of the different tested bacterial species is retained by the 2D collagen membrane up to 48 h), thus functionally mimicking the epidermal layer. The thick sponge-like 3D collagen scaffold, structurally and functionally resembling the dermal layer, is mechanically stable in wet conditions, biocompatible in vitro (seeded fibroblasts are viable and proliferate), and efficiently acts as a scaffold for fibroblast infiltration. Thus, thanks to their chemical and biological properties, CBSS derived from sea urchins might represent a promising, eco-friendly, and economically sustainable biomaterial for tissue regenerative medicine.

Quantitative evaluation of the in vivo biocompatibility and performance of freeze-cast tissue scaffolds

Quantitative methods are little used for the in vivo assessment of tissue scaffolds to evaluate biocompatibility. To complement current histological techniques, we introduce as a measure of biocompatibility a straightforward, geometric analysis for the quantitative assessment of encapsulation thickness, cross-sectional area, and biomaterial shape. Advantages of this new technique are that it enables, on the one hand, a more complete and objective comparison of scaffolds with differing compositions, architectures, and mechanical properties, and, on the other, a more objective approach to their selection for a given application. In this contribution, we focus on freeze-cast polymeric scaffolds for tissue regeneration and their subcutaneous implantation in mice for biocompatibility testing. Initially, seven different scaffold types are screened. Of these, three are selected for systematic biocompatibility studies based on histopathological criteria: EDC-NHS-crosslinked bovine collagen, EDC-NHS-crosslinked bovine collagen-nanocellulose, and chitin. Geometric models developed to quantify scaffold size, ovalization, and encapsulation thickness are tested, evaluated, and found to be a powerful and objective metric for the in vivo assessment of biocompatibility and performance of tissue scaffolds.

Marine Collagen from Alternative and Sustainable Sources: Extraction, Processing and Applications

Due to its unique properties, collagen is used in the growing fields of pharmaceutical and biomedical devices, as well as in the fields of nutraceuticals, cosmeceuticals, food and beverages. Collagen also represents a valid resource for bioplastics and biomaterials, to be used in the emerging health sectors. Recently, marine organisms have been considered as promising sources of collagen, because they do not harbor transmissible disease. In particular, fish biomass as well as by-catch organisms, such as undersized fish, jellyfish, sharks, starfish, and sponges, possess a very high collagen content. The use of discarded and underused biomass could contribute to the development of a sustainable process for collagen extraction, with a significantly reduced environmental impact. This addresses the European zero-waste strategy, which supports all three generally accepted goals of sustainability: sustainable economic well-being, environmental protection, and social well-being. A zero-waste strategy would use far fewer new raw materials and send no waste materials to landfills. In this review, we present an overview of the studies carried out on collagen obtained from by-catch organisms and fish wastes. Additionally, we discuss novel technologies based on thermoplastic processes that could be applied, likewise, as marine collagen treatment.

Marine Collagen as A Promising Biomaterial for Biomedical Applications

This review focuses on the expanding role of marine collagen (MC)-based scaffolds for biomedical applications. A scaffold-a three-dimensional (3D) structure fabricated from biomaterials-is a key supporting element for cell attachment, growth, and maintenance in 3D cell culture and tissue engineering. The mechanical and biological properties of the scaffolds influence cell morphology, behavior, and function. MC, collagen derived from marine organisms, offers advantages over mammalian collagen due to its biocompatibility, biodegradability, easy extractability, water solubility, safety, low immunogenicity, and low production costs. In recent years, the use of MC as an increasingly valuable scaffold biomaterial has drawn considerable attention from biomedical researchers. The characteristics, isolation, physical, and biochemical properties of MC are discussed as an understanding of MC in optimizing the subsequent modification and the chemistries behind important tissue engineering applications. The latest technologies behind scaffold processing are assessed and the biomedical applications of MC and MC-based scaffolds, including tissue engineering and regeneration, wound dressing, drug delivery, and therapeutic approach for diseases, especially those associated with metabolic disturbances such as obesity and diabetes, are discussed. Despite all the challenges, MC holds great promise as a biomaterial for developing medical products and therapeutics.

Clinical Applications for Tissue Engineering in Rhinology

Tissue engineering implies a number of established techniques in several fields in medicine. A thorough review of current clinical applications for tissue engineering in rhinology is addressed. Current status, as well as, published in vivo studies is presented. Moreover, relevant clinical applications and future perspectives of tissue engineering are demonstrated. There is a lack of high quality clinical studies in the literature regarding the role of tissue engineering in the rhinology field. Further research is needed to translate this concept from bench to bedside.

Physicochemical and Biocompatibility Properties of Type I Collagen from the Skin of Nile Tilapia (Oreochromis niloticus) for Biomedical Applications

The aim of this study is to investigate the physicochemical properties, biosafety, and biocompatibility of the collagen extract from the skin of Nile tilapia, and evaluate its use as a potential material for biomedical applications. Two extraction methods were used to obtain acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) from tilapia skin. Amino acid composition, FTIR, and SDS-PAGE results showed that ASC and PSC were type I collagen. The molecular form of ASC and PSC is (α₁)₂α₂. The FTIR spectra of ASC and PSC were similar, and the characteristic peaks corresponding to amide A, amide B, amide I, amide II, and amide III were 3323 cm-1, 2931 cm-1, 1677 cm-1, 1546 cm-1, and 1242 cm-1, respectively. Denaturation temperatures (Td) were 36.1 °C and 34.4 °C, respectively. SEM images showed the loose and porous structure of collagen, indicting its physical foundation for use in applications of biomedical materials. Negative results were obtained in an endotoxin test. Proliferation rates of osteoblastic (MC3T3E1) cells and fibroblast (L929) cells from mouse and human umbilical vein endothelial cells (HUVEC) were increased in the collagen-treated group compared with the controls. Furthermore, the acute systemic toxicity test showed no acute systemic toxicity of the ASC and PSC collagen sponges. These findings indicated that the collagen from Nile tilapia skin is highly biocompatible in nature and could be used as a suitable biomedical material.

Cartilage regeneration using decellularized cartilage matrix: Long-term comparison of subcutaneous and intranasal placement in a rabbit model

Autologous cartilage as donor tissue for various surgical reconstructions such as nasal septum regeneration is limited and associated with donor site morbidity. Our goal was to evaluate a new resorbable chondroconductive biomaterial made of decellularized porcine nasal septum cartilage compared with autologous native auricular cartilage as the gold standard. In order to examine the material and determine its long-term outcome further, we used subcutaneous implantation and septal implantation in an orthotopic rabbit model. In addition to non-seeded decellularized xenogenic cartilage, chondrocyte-seeded decellularized xenogenic cartilage was implanted as a septal replacement. After a three- or six-month period, the formation of newly synthesized cartilage extracellular matrix was evaluated immunohistochemically, whereas septal integrity and biocompatibility were evaluated histologically. The formation of the implanted neoseptum and form stability was analyzed by using 7-Tesla Magnetic Resonance Imaging. Good biocompatibility with no excessive rejection was demonstrated in all groups. Long-term stable and reliable septal reconstruction could be achieved in the study groups with or without cell seeding with autologous auricular chondrocytes. Autologous cell seeding was advantageous only with regard to septal perforations. Thus, cell seeding provides a benefit regarding long-term stability. However, because of slightly better biocompatibility, less pronounced septum deviation and the markedly lower effort involved, the non-seeded scaffold is favoured for possible clinical application.

Biphasic Scaffolds from Marine Collagens for Regeneration of Osteochondral Defects

Background: Collagens of marine origin are applied increasingly as alternatives to mammalian collagens in tissue engineering. The aim of the present study was to develop a biphasic scaffold from exclusively marine collagens supporting both osteogenic and chondrogenic differentiation and to find a suitable setup for in vitro chondrogenic and osteogenic differentiation of human mesenchymal stroma cells (hMSC). Methods: Biphasic scaffolds from biomimetically mineralized salmon collagen and fibrillized jellyfish collagen were fabricated by joint freeze-drying and crosslinking. Different experiments were performed to analyze the influence of cell density and TGF-β on osteogenic differentiation of the cells in the scaffolds. Gene expression analysis and analysis of cartilage extracellular matrix components were performed and activity of alkaline phosphatase was determined. Furthermore, histological sections of differentiated cells in the biphasic scaffolds were analyzed. Results: Stable biphasic scaffolds from two different marine collagens were prepared. An in vitro setup for osteochondral differentiation was developed involving (1) different seeding densities in the phases; (2) additional application of alginate hydrogel in the chondral part; (3) pre-differentiation and sequential seeding of the scaffolds and (4) osteochondral medium. Spatially separated osteogenic and chondrogenic differentiation of hMSC was achieved in this setup, while osteochondral medium in combination with the biphasic scaffolds alone was not sufficient to reach this ambition. Conclusions: Biphasic, but monolithic scaffolds from exclusively marine collagens are suitable for the development of osteochondral constructs.

Development of various composition multicomponent chitosan/fish collagen/glycerin 3D porous scaffolds: Effect on morphology, mechanical strength, biostability and cytocompatibility

The various composition multicomponent chitosan/fish collagen/glycerin 3D porous scaffolds were developed and investigated the effect of various composition chitosan/fish collagen/glycerin on scaffolds morphology, mechanical strength, biostability and cytocompatibility. The scaffolds were fabricated via freeze-drying technique. The effects of various compositions consisting in 3D scaffolds were investigated via FT-IR analysis, porosity, swelling and mechanical tests, and effect on the morphology of scaffolds investigated microscopically. The biostability and cytocompatibility tests were used to explore the ability of scaffolds to use for tissue engineering application. The average pore sizes of scaffolds were in range of 100.73±27.62-116.01±52.06, porosity 71.72±3.46-91.17±2.42%, tensile modulus in dry environment 1.47±0.08-0.17±0.03MPa, tensile modulus in wet environment 0.32±0.03-0.14±0.04MPa and biodegradation rate (at day 30) 60.38±0.70-83.48±0.28%. In vitro culture of human fibroblasts and keratinocytes showed that the various composition multicomponent 3D scaffolds were good cytocompatibility however, the scaffolds contained high amount of fish collagen excellently facilitated cell proliferation and adhesion. It was found that the high amount fish collagen and glycerin scaffolds have high porosity, enough mechanical strength and biostability, and excellent cytocompatibility.

Laser surface modification of decellularized extracellular cartilage matrix for cartilage tissue engineering

The implantation of autologous cartilage as the gold standard operative procedure for the reconstruction of cartilage defects in the head and neck region unfortunately implicates a variety of negative effects at the donor site. Tissue-engineered cartilage appears to be a promising alternative. However, due to the complex requirements, the optimal material is yet to be determined. As demonstrated previously, decellularized porcine cartilage (DECM) might be a good option to engineer vital cartilage. As the dense structure of DECM limits cellular infiltration, we investigated surface modifications of the scaffolds by carbon dioxide (CO₂) and Er:YAG laser application to facilitate the migration of chondrocytes inside the scaffold. After laser treatment, the scaffolds were seeded with human nasal septal chondrocytes and analyzed with respect to cell migration and formation of new extracellular matrix proteins. Histology, immunohistochemistry, SEM, and TEM examination revealed an increase of the scaffolds' surface area with proliferation of cell numbers on the scaffolds for both laser types. The lack of cytotoxic effects was demonstrated by standard cytotoxicity testing. However, a thermal denaturation area seemed to hinder the migration of the chondrocytes inside the scaffolds, even more so after CO₂ laser treatment. Therefore, the Er:YAG laser seemed to be better suitable. Further modifications of the laser adjustments or the use of alternative laser systems might be advantageous for surface enlargement and to facilitate migration of chondrocytes into the scaffold in one step.

Impact of expansion and redifferentiation under hypothermia on chondrogenic capacity of cultured human septal chondrocytes

A critical limitation in the cultivation of cartilage for tissue engineering is the dedifferentiation in chondrocytes, mainly during in vitro amplification. Despite many previous studies investigating the influence of various conditions, no data exist concerning the effects of hypothermia. Our aim has been to influence chondrocyte dedifferentiation in vitro by hypothermic conditions. Chondrocytes were isolated from cartilage biopsies and seeded in monolayer and in three-dimensional pellet-cultures. Each cell culture was either performed at 32.2°C or 37°C during amplification. Additionally, the influence of the redifferentiation of chondrocytes in three-dimensional cell culture was examined at 32.2°C and 37°C after amplification at 32.2°C or 37°C. An 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay was used to measure cell proliferation in monolayer, whereas the polymerase chain reaction and immunohistochemical and histological staining were used in three-dimensional pellet-cultures. Real-time polymerase chain reaction was employed to measure the relative expression of the target genes collagen II, collagen I, aggrecan and versican. Ratios were estimated between collagen II/collagen I and aggrecan/versican to evaluate differentiation. A higher value of these ratios indicated an advantageous status of differentiation. In monolayer, hypothermia at 32.2°C slowed down the proliferation rate of chondrocytes significantly, being up to two times lower at 32.2°C compared with culture at 37°C. Simultaneously, hypothermia in monolayer decelerated dedifferentiation. The ratio of aggrecan/versican was significantly higher at 32.2°C compared with that at 37°C. In three-dimensional pellet-culture, the chondrocytes redifferentiated at 32.2°C and at 37°C, and this process is more distinct at 37°C than at 32.2°C. Similar results were obtained for the ratios of collagen II/collagen I and aggrecan/versican and were supported by immunochemical and histological staining. Thus, hypothermic conditions for chondrocytes are mainly advantageous in monolayer culture. In three-dimensional pellet-culture, redifferentiation predominates at 37°C compared with at 32.2°C. In particular, the results from the monolayer cultures show potential in the avoidance of dedifferentiation.

Nasal chondrocytes as a neural crest-derived cell source for regenerative medicine

Cells deriving from neural crest are generally acknowledged during embryonic development for their multipotency and plasticity, accounting for their capacity to generate various cell and tissue types even across germ layers. At least partial preservation of some of these properties in adulthood makes neural crest derived cells of large interest for regenerative purposes. Chondrocytes from fully mature nasal septum cartilage in adults are also derivatives of neural crest cells and were recently demonstrated to be able not only to maintain functionality across serial cloning, as surrogate self-renewal test, but also to respond and adapt to heterotopic transplantation sites. Based on these findings, cartilage grafts engineered by nasal chondrocytes were clinically used to reconstitute the nasal alar lobule and to repair articular cartilage defects. This article discusses further perspectives of potential clinical utility for nasal chondrocytes in musculoskeletal regeneration. It then highlights the need to derive deeper understanding of their biological properties in order to inform on possible therapeutic modes of action. This acquired knowledge will help to optimise manufacturing conditions to guarantee defined functional traits associated with safety and therapeutic potency of nasal chondrocytes in regenerative medicine.

Repair of bone defects in vivo using tissue engineered hypertrophic cartilage grafts produced from nasal chondrocytes

The regeneration of large bone defects remains clinically challenging. The aim of our study was to use a rat model to use nasal chondrocytes to engineer a hypertrophic cartilage tissue which could be remodelled into bone in vivo by endochondral ossification. Primary adult rat nasal chondrocytes were isolated from the nasal septum, the cell numbers expanded in monolayer culture and the cells cultured in vitro on polyglycolic acid scaffolds in chondrogenic medium for culture periods of 5-10 weeks. Hypertrophic differentiation was assessed by determining the temporal expression of key marker genes and proteins involved in hypertrophic cartilage formation. The temporal changes in the genes measured reflected the temporal changes observed in the growth plate. Collagen II gene expression increased 6 fold by day 7 and was then significantly downregulated from day 14 onwards. Conversely, collagen X gene expression was detectable by day 14 and increased 100-fold by day 35. The temporal increase in collagen X expression was mirrored by increases in alkaline phosphatase gene expression which also was detectable by day 14 with a 30-fold increase in gene expression by day 35. Histological and immunohistochemical analysis of the engineered constructs showed increased chondrocyte cell volume (31-45 μm), deposition of collagen X in the extracellular matrix and expression of alkaline phosphatase activity. However, no cartilage mineralisation was observed in in vitro culture of up to 10 weeks. On subcutaneous implantation of the hypertrophic engineered constructs, the grafts became vascularised, cartilage mineralisation occurred and loss of the proteoglycan in the matrix was observed. Implantation of the hypertrophic engineered constructs into a rat cranial defect resulted in angiogenesis, mineralisation and remodelling of the cartilage tissue into bone. Micro-CT analysis indicated that defects which received the engineered hypertrophic constructs showed 38.48% in bone volume compared to 7.01% in the control defects. Development of tissue engineered hypertrophic cartilage to use as a bone graft substitute is an exciting development in regenerative medicine. This is a proof of principal study demonstrating the potential of nasal chondrocytes to engineer hypertrophic cartilage which will remodel into bone on in vivo transplantation. This approach to making engineered hypertrophic cartilage grafts could form the basis of a new potential future clinical treatment for maxillofacial reconstruction.

Jellyfish collagen and alginate: Combined marine materials for superior chondrogenesis of hMSC

Marine, hybrid constructs of porous scaffolds from fibrillized jellyfish collagen and alginate hydrogel are mimicking both of the main tissue components of cartilage, thus being a promising approach for chondrogenic differentiation of human mesenchymal stem cells (hMSC). Investigating their potential for articular cartilage repair, the present study examined scaffolds being either infiltrated with an alginate-cell-suspension (ACS) or seeded with hMSC and embedded in alginate after cell adhesion (EAS). Hybrid constructs with 2×10(5) and 4.5×10(5)hMSC/scaffold were compared to hMSC encapsulated in pure alginate discs, both chondrogenically stimulated for 21days. Typical round, chondrocyte-like morphology was observed in pure alginate gels and ACS scaffolds, while cells in EAS were elongated and tightly attached to the collagen pores. Col 2 gene expression was comparable in all scaffold types examined. However, the Col 2/Col 1 ratio was higher for pure alginate discs and ACS scaffolds compared to EAS. In contrast, cells in EAS scaffolds displayed higher gene expression of Sox 9, Col 11 and ACAN compared to ACS and pure alginate. Secretion of sulfated glycosaminoglycans (sGAG) was comparable for ACS and EAS scaffolds. In conclusion hybrid constructs of jellyfish collagen and alginate support hMSC chondrogenic differentiation and provide more stable and constructs compared to pure hydrogels.

Modulation of chondrogenic differentiation of human mesenchymal stem cells in jellyfish collagen scaffolds by cell density and culture medium

Studies on tissue-engineering approaches for the regeneration of traumatized cartilage focus increasingly on multipotent human mesenchymal stem cells (hMSCs) as an alternative to autologous chondrocytes. The present study applied porous scaffolds made of collagen from the jellyfish Rhopilema esculentum for the in vitro chondrogenic differentiation of hMSCs. Culture conditions in those scaffolds differ from conditions in high-density pellet cultures, making a re-examination of these data necessary. We systematically investigated the influence of seeding density, basic culture media [Dulbecco's modified Eagle's medium (DMEM), α-minimum essential medium (α-MEM)] with varying glucose content and supplementation with fetal calf serum (FCS) or bovine serum albumin (BSA) on the chondrogenic differentiation of hMSCs. Gene expression analyses of selected markers for chondrogenic differentiation and hypertrophic development were conducted. Furthermore, the production of cartilage extracellular matrix (ECM) was analysed by quantification of sulphated glycosaminoglycan and collagen type II contents. The strongest upregulation of chondrogenic markers, along with the highest ECM deposition was observed in scaffolds seeded with 2.4 × 10⁶ cells/cm³ after cultivation in high-glucose DMEM and 0.125% BSA. Lower seeding densities compared to high-density pellet cultures were sufficient to induce in vitro chondrogenic differentiation of hMSCs in collagen scaffolds, which reduces the amount of cells required for the seeding of scaffolds and thus the monolayer expansion period. Furthermore, examination of the impact of FCS and α-MEM on chondrogenic MSC differentiation is an important prerequisite for the development of an osteochondral medium for simultaneous osteogenic and chondrogenic differentiation in biphasic scaffolds for osteochondral tissue regeneration. Copyright © 2015 John Wiley & Sons, Ltd.

Gut-spilling in chordates: evisceration in the tropical ascidian Polycarpa mytiligera

The ejection of internal organs, i.e., evisceration, is a well-known phenomenon in sea-cucumbers. We report the ability of a member of the Chordate phyla, the tropical ascidian Polycarpa mytiligera, to eviscerate and regenerate its gut within 12 days, and to rebuild its branchial sac within 19 days. Evisceration occurred within 4–43 seconds of gentle mechanical pressure exerted on the tunic in 47% of the tested P. mytiligera. Individuals were able to discard up to 3/4 of their digestive tract via the incurrent siphon by rupture of the branchial sac in this area. Although chemical analysis revealed no significant levels of toxic compounds, the eviscerated guts were unpalatable to the triggerfish and pufferfish on which they were tested, suggesting evisceration as a defense mechanism. Given the close affinity of ascidians to vertebrates, the regeneration pathway of the viscera and branchial sac of ascidians suggests its potential beneficial application in soft tissue regeneration research.

Electrospun gelatin/polycaprolactone nanofibrous membranes combined with a coculture of bone marrow stromal cells and chondrocytes for cartilage engineering

Electrospinning has recently received considerable attention, showing notable potential as a novel method of scaffold fabrication for cartilage engineering. The aim of this study was to use a coculture strategy of chondrocytes combined with electrospun gelatin/polycaprolactone (GT/PCL) membranes, instead of pure chondrocytes, to evaluate the formation of cartilaginous tissue. We prepared the GT/PCL membranes, seeded bone marrow stromal cell (BMSC)/chondrocyte cocultures (75% BMSCs and 25% chondrocytes) in a sandwich model in vitro, and then implanted the constructs subcutaneously into nude mice for 12 weeks. Gross observation, histological and immunohistological evaluation, glycosaminoglycan analyses, Young’s modulus measurement, and immunofluorescence staining were performed postimplantation. We found that the coculture group formed mature cartilage-like tissue, with no statistically significant difference from the chondrocyte group, and labeled BMSCs could differentiate into chondrocyte-like cells under the chondrogenic niche of chondrocytes. This entire strategy indicates that GT/PCL membranes are also a suitable scaffold for stem cell-based cartilage engineering and may provide a potentially clinically feasible approach for cartilage repairs.

Jellyfish collagen matrices conserve the chondrogenic phenotype in two- and three-dimensional collagen matrices

Cartilage is a tissue with a very low capability of self-repair and the search for suitable materials supporting the chondrogenic phenotype and thus avoiding fibrotic dedifferentiation for matrix-associated chondrocyte transplantation (MACI) is ongoing. Jellyfish collagen was thought to be a suitable material mainly because of its good availability and easy handling. Collagen was extracted from jellyfish Rhopilema esculentum and the spreading of porcine chondrocytes on two (2D) and three dimensional (3D) collagen matrices examined in comparison with vertebrate collagens, placenta collagen and a commercially available matrix from porcine collagen type I (Optimaix®). In 2D, most chondrocytes kept their round shape on jellyfish collagen and vertebrate collagen type II compared with vertebrate collagen type I. This was also confirmed in 3D experiments, where chondrocytes preserved their phenotype on jellyfish collagen, as indicated by high collagen II/(II + I) ratios (≥54 % and ~92 % collagen type II in mRNA and protein, respectively) and no proliferation during 28 days of cultivation. These observations were discussed with a view to potential structural differences of jellyfish collagen, which might influence the integrin-mediated adhesion mechanisms of vertebrate cells on jellyfish collagen. This probably results from a lack of integrin-binding sites and the existence of an alternative binding mechanism such that cells kept their round shape on jellyfish collagen, preventing chondrocytes from dedifferentiation. Thus, collagen from R. esculentum is a very suitable and promising material for cartilage tissue engineering. Copyright © 2015 John Wiley & Sons, Ltd.

Marine Collagen: An Emerging Player in Biomedical applications

Mammalian collagen is a multifactorial biomaterial that is widely used for beneficial purposes in the advanced biomedical technologies. Generally, biomedical applicable collagen is extracted from the mammalian body, but it can also be derived from marine species. Recently, mammalian tissues collagen proteins are considered a great pathological risk for transmitted diseases, because purification of such protein is very challenging and needs efficient tool to avoid structure alteration. Thus, difficult extraction process and high cost decreased mammalian collagen demands for beneficial effects compared to marine collagen. In contrast, marine collagen is safe and easy to extract, however this potential source of collagen is hindered by low denaturing temperature, which is considered a main hurdle in the beneficial effects of marine collagen. Characterization and biomedical applications of marine collagen are in transition state and yet to be discovered. Therefore, an attempt was made to summarize the recent knowledge regarding different aspects of marine collagen applications in the biomedical engineering field.

Evaluation of Autogenous Engineered Septal Cartilage Grafts in Rabbits- A Minimally Invasive Preclinical Model

OBJECTIVES

Evaluate safety of autogenous engineered septal neocartilage grafts.Compare properties of implanted grafts versus in vitro controls.

STUDY DESIGN

Prospective, basic science.

SETTING

Research laboratory.

METHODS

Constructs were fabricated from septal cartilage and serum harvested from adult rabbits and then cultured in vitro or implanted on the nasal dorsum as autogenous grafts for 30 or 60 days. Rabbits were monitored for local and systemic complications. Histological, biochemical and biomechanical properties of implanted and in vitro constructs were evaluated and compared.

RESULTS

No systemic or serious local complications were observed. After 30 and 60 days, implanted constructs contained more DNA (p<0.01) and less sGAG per DNA (p<0.05) when compared with in vitro controls. Confined compressive aggregate moduli were also higher in implanted constructs when compared with in vitro controls (p<0.05) and increased with longer in vivo incubation time (p<0.01). Implanted constructs displayed resorption rates of 20-45 percent. Calcium deposition in implanted constructs was observed using alizarin red histochemistry and microtomographic analyses.

CONCLUSION

Autogenous engineered septal cartilage grafts were well tolerated. As seen in experiments with athymic mice, implanted constructs accumulated more DNA and less sGAG when compared with in vitro controls. Confined compressive aggregate moduli were also higher in implanted constructs. Implanted constructs displayed resorption rates similar to previously published studies using autogenous implants of native cartilage. The basis for observed calcification in implanted constructs and its effect on long-term graft efficacy is unknown at this time and will be a focus of future studies.

Evolving marine biomimetics for regenerative dentistry

New products that help make human tissue and organ regeneration more effective are in high demand and include materials, structures and substrates that drive cell-to-tissue transformations, orchestrate anatomical assembly and tissue integration with biology. Marine organisms are exemplary bioresources that have extensive possibilities in supporting and facilitating development of human tissue substitutes. Such organisms represent a deep and diverse reserve of materials, substrates and structures that can facilitate tissue reconstruction within lab-based cultures. The reason is that they possess sophisticated structures, architectures and biomaterial designs that are still difficult to replicate using synthetic processes, so far. These products offer tantalizing pre-made options that are versatile, adaptable and have many functions for current tissue engineers seeking fresh solutions to the deficiencies in existing dental biomaterials, which lack the intrinsic elements of biofunctioning, structural and mechanical design to regenerate anatomically correct dental tissues both in the culture dish and in vivo.