Scaffold-free cartilage tissue engineering with a small population of human nasoseptal chondrocytes

Biomaterials-based additive manufacturing for customized bioengineering in management of otolaryngology: a comprehensive review

Three-dimensional (3D)/four-dimensional (4D) printing, also known as additive manufacturing or fast prototyping, is a manufacturing technique that uses a digital model to generate a 3D/4D solid product. The usage of biomaterials with 3D/4D printers in the pharma and healthcare industries is gaining significant popularity. 3D printing has mostly been employed in the domain of otolaryngology to build portable anatomical models, personalized patient-centric implants, biologic tissue scaffolds, surgical planning in individuals with challenging conditions, and surgical training. Although identical to 3D printing technology in this application, 4D printing technology comprises a fourth dimension of time. With the use of 4D printing, a printed structure may alter over time under various stimuli. Smart polymeric materials are also generally denoted as bioinks are frequently employed in tissue engineering applications of 3D/4D printing. In general, 4D printing could significantly improve the safety and efficacy of otolaryngology therapies. The use of bioprinting in otolaryngology has an opportunity to transform the treatment of diseases influencing the ear, nose, and throat as well as the field of tissue regeneration. The present review briefs on polymeric material including biomaterials and cells used in the manufacturing of patient centric 3D/4D bio-printed products utilized in management of otolaryngology.

Cartilage Tissue Engineering for Nasal Alar and Auricular Reconstruction: A Critical Review of the Literature and Implications for Practice in Dermatologic Surgery

BACKGROUND

Reconstructing defects requiring replacement of nasal or auricular cartilage after Mohs micrographic surgery can at times be challenging. While autologous cartilage grafting is considered the mainstay for repair, it may be limited by cartilage quality/quantity, donor site availability/morbidity, and surgical complications. Tissue-engineered cartilage has recently shown promise for repairing properly selected facial defects.

OBJECTIVE

To (1) provide a comprehensive overview of the literature on the use of tissue-engineered cartilage for nasal alar and auricular defects, and (2) discuss this technology's advantages and future implications for dermatologic surgery.

MATERIALS AND METHODS

A literature search was performed using PubMed/MEDLINE and Google Scholar databases. Studies discussing nasal alar or auricular cartilage tissue engineering were included.

RESULTS

Twenty-seven studies were included. Using minimal donor tissue, tissue-engineered cartilage can create patient-specific, three-dimensional constructs that are biomechanically and histologically similar to human cartilage. The constructs maintain their shape and structural integrity after implantation into animal and human models.

CONCLUSION

Tissue-engineered cartilage may be able to replace native cartilage in reconstructing nasal alar and auricular defects given its ability to overcome several limitations of autologous cartilage grafting. Although further research is necessary, dermatologic surgeons should be aware of this innovative technique and its future implications.

Cell Cycle Synchronization of Primary Articular Chondrocytes Enhances Chondrogenesis

OBJECTIVE

Although tissue engineering is a promising option for articular cartilage repair, it has been challenging to generate functional cartilaginous tissue. While the synthetic response of chondrocytes can be influenced by various means, most approaches treat chondrocytes as a homogeneous population that would respond similarly. However, isolated cells heterogeneously progress through the cell cycle, which can affect macromolecular biosynthesis. As it is possible to synchronize cells within discrete cell cycle phases, the purpose of this study was to investigate the effects of cell cycle synchronization on the chondrogenic potential of primary articular chondrocytes.

DESIGN

Different methods of cell synchronization (serum starvation, thymidine, nocodazole, aphidicolin, and RO-3306) were tested for their ability to synchronize primary articular chondrocytes during the process of cell isolation. Cells (unsynchronized and synchronized) were then encapsulated in alginate gels, cultured for 4 weeks, and analyzed for their structural and biochemical properties.

RESULTS

The double-thymidine method yielded the highest level of cell purity, with cells synchronized in S phase. While the cells started to lose synchronization after 24 hours, tissue constructs developed from initially S phase synchronized cells had significantly higher glycosaminoglycan and collagen II amounts than those developed using unsynchronized cells.

CONCLUSIONS

Initial synchronization led to long-term changes in cartilaginous tissue formation. This effect was postulated to be due to the rapid auto-induction of TGF-βs by actively dividing S phase cells, thereby stimulating chondrogenesis. Cell synchronization methods may also be applied in conjunction with redifferentiation methods to improve the chondrogenic potential of dedifferentiated or diseased chondrocytes.

[Research progress of autogenous cartilage scaffold carving method in rhinoplasty]

OBJECTIVE

To summarize the research progress of autogenous cartilage scaffold carving method in rhinoplasty.

METHODS

The relevant literature about the autogenous cartilage scaffold carving methods in rhinoplasty in resent years at home and abroad was reviewed, and the carving skills, shape, and application scope of different parts of nasal scaffolds were summarized and analyzed.

RESULTS

Willow-leaf shape is still the main method of cartilage scaffold in the back of the nose. However, in nasal reconstruction, it can be carved into an L-shaped scaffold with the nasal columella scaffold through mortise and tenon structure. And it can also crush the autologous cartilage and wrap it with the autologous fascia tissue to form a new nasal dorsal scaffold. The nasal tip scaffold is improved by changing the shape of traditional nasal tip cartilage cap and wrapping with fascia tissue; the nasal alar scaffold has M-shape, q-shape, carving methods; the nasal columella and nasal septum are mostly used "2+2" combined fixed scaffold. The cartilage scaffolds of lateral nose and nasal base are mainly carved in the shape of "" and crescent.

CONCLUSION

As a rhinoplasty scaffold, there are various carving methods for autogenous cartilage. With the innovation of surgical technique and the improvement of sculpting technique, the effect of autologous cartilage graft in rhinoplasty is getting better and better; meanwhile, tissue engineered cartilage is being applied in rhinoplasty.

A novel 3D histotypic cartilage construct engineered by supercritical carbon dioxide decellularized porcine nasal cartilage graft and chondrocytes exhibited chondrogenic capability in vitro

Augmentative and reconstructive rhinoplasty surgical procedures use autologous tissue grafts or synthetic grafts to repair the nasal defect and aesthetic reconstruction. Donor site trauma and morbidity are common in autologous grafts. The desperate need for the production of grafted 3D cartilage tissues as rhinoplasty grafts without the adverse effect is the need of the hour. In the present study, we developed a bioactive 3D histotypic construct engineered with the various ratio of adipose-derived stem cells (ADSC) and chondrocytes together with decellularized porcine nasal cartilage graft (dPNCG). We decellularized porcine nasal cartilage using supercritical carbon dioxide (SCCO2) extraction technology. dPNCG was characterized by H&E, DAPI, alcian blue staining, scanning electron microscopy and residual DNA content, which demonstrated complete decellularization. 3D histotypic constructs were engineered using dPNCG, rat ADSC and chondrocytes with different percentage of cells and cultured for 21 days. dPNCG together with 100% chondrocytes produced a solid mass of 3D histotypic cartilage with significant production of glycosaminoglycans. H&E and alcian blue staining showed an intact mass, with cartilage granules bound to one another by extracellular matrix and proteoglycan, to form a 3D structure. Besides, the expression of chondrogenic markers, type II collagen, aggrecan and SOX-9 were elevated indicating chondrocytes cultured on dPNCG substrate facilitates the synthesis of type II collagen along with extracellular matrix to produce 3D histotypic cartilage. To conclude, dPNCG is an excellent substrate scaffold that might offer a suitable environment for chondrocytes to produce 3D histotypic cartilage. This engineered 3D construct might serve as a promising future candidate for cartilage tissue engineering in rhinoplasty.

Biosafety evaluation of culture-expanded human chondrocytes with growth factor cocktail: a preclinical study

The scarcity of chondrocytes is a major challenge for cartilage tissue engineering. Monolayer expansion is necessary to amplify the limited number of chondrocytes needed for clinical application. Growth factors are often added to improve monolayer culture conditions, promoting proliferation, and enhancing chondrogenesis. Limited knowledge on the biosafety of the cell products manipulated with growth factors in culture has driven this study to evaluate the impact of growth factor cocktail supplements in chondrocyte culture medium on chondrocyte genetic stability and tumorigenicity. The growth factors were basic fibroblast growth factor (b-FGF), transforming growth factor β2 (TGF β2), insulin-like growth factor 1 (IGF-1), insulin-transferrin-selenium (ITS), and platelet-derived growth factor (PD-GF). Nasal septal chondrocytes cultured in growth factor cocktail exhibited a significantly high proliferative capacity. Comet assay revealed no significant DNA damage. Flow cytometry showed chondrocytes were mostly at G0-G1 phase, exhibiting normal cell cycle profile with no aneuploidy. We observed a decreased tumour suppressor genes’ expression (p53, p21, pRB) and no TP53 mutations or tumour formation after 6 months of implantation in nude mice. Our data suggest growth factor cocktail has a low risk of inducing genotoxic and tumorigenic effects on chondrocytes up to passage 6 with 16.6 population doublings. This preclinical tumorigenicity and genetic instability evaluation is crucial for further clinical works.

Tissue engineering applications in otolaryngology-The state of translation

While tissue engineering holds significant potential to address current limitations in reconstructive surgery of the head and neck, few constructs have made their way into routine clinical use. In this review, we aim to appraise the state of head and neck tissue engineering over the past five years, with a specific focus on otologic, nasal, craniofacial bone, and laryngotracheal applications. A comprehensive scoping search of the PubMed database was performed and over 2000 article hits were returned with 290 articles included in the final review. These publications have addressed the hallmark characteristics of tissue engineering (cellular source, scaffold, and growth signaling) for head and neck anatomical sites. While there have been promising reports of effective tissue engineered interventions in small groups of human patients, the majority of research remains constrained to in vitro and in vivo studies aimed at furthering the understanding of the biological processes involved in tissue engineering. Further, differences in functional and cosmetic properties of the ear, nose, airway, and craniofacial bone affect the emphasis of investigation at each site. While otolaryngologists currently play a role in tissue engineering translational research, continued multidisciplinary efforts will likely be required to push the state of translation towards tissue-engineered constructs available for routine clinical use.

LEVEL OF EVIDENCE

NA.

Computational technology for nasal cartilage-related clinical research and application

Surgeons need to understand the effects of the nasal cartilage on facial morphology, the function of both soft tissues and hard tissues and nasal function when performing nasal surgery. In nasal cartilage-related surgery, the main goals for clinical research should include clarification of surgical goals, rationalization of surgical methods, precision and personalization of surgical design and preparation and improved convenience of doctor-patient communication. Computational technology has become an effective way to achieve these goals. Advances in three-dimensional (3D) imaging technology will promote nasal cartilage-related applications, including research on computational modelling technology, computational simulation technology, virtual surgery planning and 3D printing technology. These technologies are destined to revolutionize nasal surgery further. In this review, we summarize the advantages, latest findings and application progress of various computational technologies used in clinical nasal cartilage-related work and research. The application prospects of each technique are also discussed.

Toward tissue-engineering of nasal cartilages

Nasal cartilage pathologies are common; for example, up to 80% of people are afflicted by deviated nasal septum conditions. Because cartilage provides the supportive framework of the nose, afflicted patients suffer low quality of life. To correct pathologies, graft cartilage is often required. Grafts are currently sourced from the patient's septum, ear, or rib. However, their use yields donor site morbidity and is limited by tissue quantity and quality. Additionally, rhinoplasty revision rates exceed 15%, exacerbating the shortage of graft cartilage. Alternative grafts, such as irradiated allogeneic rib cartilage, are associated with complications. Tissue-engineered neocartilage holds promise to address the limitations of current grafts. The engineering design process may be used to create suitable graft tissues. This process begins by identifying the surgeon's needs. Second, nasal cartilages' properties must be understood to define engineering design criteria. Limited investigations have examined nasal cartilage properties; numerous additional studies need to be performed to examine topographical variations, for example. Third, tissue-engineering processes must be applied to achieve the engineering design criteria. Within the recent past, strategies have frequently utilized human septal chondrocytes. As autologous and allogeneic rib graft cartilage is used, its suitability as a cell source should also be examined. Fourth, quantitative verification of engineered neocartilage is critical to check for successful achievement of the engineering design criteria. Finally, following the FDA paradigm, engineered neocartilage must be orthotopically validated in animals. Together, these steps delineate a path to engineer functional nasal neocartilages that may, ultimately, be used to treat human patients. STATEMENT OF SIGNIFICANCE: Nasal cartilage pathologies are common and lead to greatly diminished quality of life. The ability to correct pathologies is limited by cartilage graft quality and quantity, as well as donor site morbidity and surgical complications, such as infection and resorption. Despite the significance of nasal cartilage pathologies and high rhinoplasty revision rates (15%), little characterization and tissue-engineering work has been performed compared to other cartilages, such as articular cartilage. Furthermore, most work is published in clinical journals, with little in biomedical engineering. Therefore, this review discusses what nasal cartilage properties are known, summarizes the current state of nasal cartilage tissue-engineering, and makes recommendations via the engineering design process toward engineering functional nasal neocartilage to address current limitations.

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.

Age-related histologic and biochemical changes in auricular and septal cartilage

OBJECTIVES/HYPOTHESIS

To characterize the histologic and biochemical properties of auricular and septal cartilage and analyze age-related changes in middle-aged to older adults.

STUDY DESIGN

Cross-sectional study of auricular and septal cartilage from 33 fresh cadavers.

METHODS

Auricular and septal cartilage specimens were stained using Safranin O for glycosaminoglycans, Verhoeff's stain for elastin, and Masson's trichrome for collagen. Percentage of tissue stained, cell density and size were quantified. Relationships between donor characteristics and histologic properties were evaluated using mixed model analyses.

RESULTS

The average donor age was 75 years (standard deviation = 11 years; range, 55-93 years). In auricular cartilage, each 1-year increase in age was associated with a 0.97% decrease in glycosaminoglycans (P < .001) and a 0.98% decrease in elastin (P < .001). In septal cartilage, glycosaminoglycans decreased 2.4% per year (P < .001). Age did not affect collagen content significantly in auricular (P = .417) or septal cartilage (P = .284). Cell density and cell size declined with age in auricular (both P < .001) and septal cartilage (P = .044, P = .032, respectively). Compared to septal cartilage in patients of all ages, auricular cartilage had more glycosaminoglycans, less collagen, higher cell density, and smaller cells.

CONCLUSIONS

In auricular and septal cartilage, glycosaminoglycans, elastin, cell density, and cell size decrease significantly with age in patients over 55 years of age. Glycosaminoglycan content declines faster with age in septal cartilage than auricular cartilage. These age-related changes may affect biomechanical properties and tissue viability, and thereby have implications for graft choice in functional, aesthetic, and reconstructive nasal surgery.

LEVEL OF EVIDENCE

NA. Laryngoscope, 127:E399-E407, 2017.