Properties of the Nasal Cartilage, from Development to Adulthood: A Scoping Review

Cartilage Tissue Engineering in Multilayer Tissue Regeneration

The functional and structural integrity of the tissue/organ can be compromised in multilayer reconstructive applications involving cartilage tissue. Therefore, multilayer structures are needed for cartilage applications. In this review, we have examined multilayer scaffolds for use in the treatment of damage to organs such as the trachea, joint, nose, and ear, including the multilayer cartilage structure, but we have generally seen that they have potential applications in trachea and joint regeneration. In conclusion, when the existing studies are examined, the results are promising for the trachea and joint connections, but are still limited for the nasal and ear. It may have promising implications in the future in terms of reducing the invasiveness of existing grafting techniques used in the reconstruction of tissues with multilayered layers.

Biochemical Variability of Nasal Cartilages: Implications in Functional Rhinoplasty

INTRODUCTION

Nasal valve compromise is a common issue for patients presenting to an otolaryngologist. Anatomically, the dorsal septal cartilage (DSA) articulates with the upper lateral nasal cartilage (ULC). When the ULC weakens, it is prone to collapse and may result in nasal obstruction. Our objectives were to analyze histological differences between quadrangular and DSA nasal cartilages and compare histological composition of these tissues among patients with diagnosis of nasal valve compromise (NVC) versus those without NVC (no NVC).

METHODS

Prospective cross-sectional study of nasal cartilages from seventy-three (73) live donors. Quadrangular cartilage (QC), and DSA from patients undergoing septorhinoplasty were collected. Safranin O histochemical staining was used to observe glycosaminoglycans (GAGs) content and cell count. Masson's Trichrome staining was used to assess collagen content in these nasal cartilages.

RESULTS

Mean GAG content was lower in DSA compared with QUAD cartilage (68.18% vs. 87.22%, p < 0.0001), and was lowest in DSA of patients with NVC (59.07%). Mean collagen content was higher in DSA compared with QUAD cartilage, (65.43% vs. 46.65%, p = 0.0002), and was highest in DSA of patients with NVC (74.86%).

CONCLUSION

The DSA showed decreased GAG and increased collagen content compared with quadrangular cartilage. Within the DSA subsite, patients with presurgical NVC had the lowest GAG and highest collagen levels. This observation suggests that the biochemical composition of the DSA may contribute to its weakening, potentially resulting in its inability to withstand minor trauma and/or the effects of aging, ultimately leading to NVC.

LEVEL OF EVIDENCE

N/A Laryngoscope, 134:4252-4258, 2024.

Impact of Tissue Handling and Size Modification on Septal Chondrocyte Viability

INTRODUCTION

The physical modification of cartilage grafts during rhinoplasty risks chondrocyte death at the margins where the tissue is cut. This study compares chondrocyte viability between diced, scaled, and pate samples in human models, and further computes percent chondrocyte viability as a function of sequential dicing size in a computational model.

METHODS

Septal cartilage from 11 individuals was prepared as follows: diced (1 mm cubic), scaled (shaved to <1 mm thickness ~ translucent), pate (0.02 g of scraped cartilage surface), positive control (2 × 2 mm diced), and negative control (2 × 2 mm diced soaked in 70% EtOH). Viability analysis was performed using Live/Dead assay™ and confocal microscopy. Numerical simulation of cartilage dicing in 0.05 mm increments was performed using MATLAB assuming 250 chondrocytes/mm3 with each average chondrocyte size of 65 μm2.

RESULTS

Chondrocyte viability was similar between 1 mm diced cartilage, scaled cartilage, and positive control samples (p > 0.05). Conversely, pate samples had significantly less viability compared to positive controls, diced samples, and scaled samples (all p < 0.01 after Bonferroni correction). Pate samples had similar chondrocyte viability compared to negative controls (p = 0.36). On computational modeling, cartilage viability decreased to 50% as the diced sample was cut from 1 mm edge length to 0.7-0.8 mm. Similarly, cartilage viability decreased to 26% at 0.55-0.65 mm, 11% at 0.4-0.5 mm, and <5% at <0.4 mm edge length.

CONCLUSION

Modifying septal cartilage grafts into 1 mm diced or scaled samples maintains ideal chondrocyte viability whereas pate preparations result in significant chondrocyte death. According to computational analysis, chondrocyte viability sharply decreases as the cartilage is diced below 0.7-0.8 mm.

LEVEL OF EVIDENCE

N/A Laryngoscope, 134:4259-4265, 2024.

Role of Growth Factors in Nasal Cartilage Development and Molding: A Comprehensive Review

This review aims to investigate the properties of growth factors concerning the morphogenesis and development of nasal cartilage, which is fundamentally important for facial form and appearance. Since cartilage lacks a blood supply, it is more difficult to regenerate, as cartilage tissue obtains sustenance by diffusion. Cytokines are signalling molecules that control chondrocyte metabolism and extracellular matrix formation, which is required for cartilage development, homeostasis, and healing. Some craniofacial illnesses alter the composition of the cartilage and the structural organization of growth factors, allowing for moulding. TGF-β (transforming growth factor-β) encourages chondrocyte differentiation, whereas IGF-1 (insulin-like growth factor-1) stimulates cartilage-forming collagen synthesis and chondrocyte multiplication. We used the scoping review approach to present current research on the role of growth factors in the creation and architecture of nasal cartilage. We generally observed this structure before conducting specific experiments to determine the impact of growth agents on the development of chondrocytes and cartilage. Prominent findings increase our understanding of how growth factors influence the extracellular matrix, cell activities and features, and cartilage growth rate; all are critical for cartilage tissue development and repair. Research into growth factors and their physiological interactions with cartilage may help improve treatment's functional and aesthetic outcomes and our understanding of the origins and consequences of nasal congenital anomalies. This study emphasizes the importance of expanding knowledge and experience, as well as the use of growth factors in clinical practice, to stimulate cartilage development.

An overview of nasal cartilage bioprinting: from bench to bedside

Nasal cartilage diseases and injuries are known as significant challenges in reconstructive medicine, affecting a substantial number of individuals worldwide. In recent years, the advent of three-dimensional (3D) bioprinting has emerged as a promising approach for nasal cartilage reconstruction, offering potential breakthroughs in the field of regenerative medicine. This paper provides an overview of the methods and challenges associated with 3D bioprinting technologies in the procedure of reconstructing nasal cartilage tissue. The process of 3D bioprinting entails generating a digital 3D model using biomedical imaging techniques and computer-aided design to integrate both internal and external scaffold features. Then, bioinks which consist of biomaterials, cell types, and bioactive chemicals, are applied to facilitate the precise layer-by-layer bioprinting of tissue-engineered scaffolds. After undergoing in vitro and in vivo experiments, this process results in the development of the physiologically functional integrity of the tissue. The advantages of 3D bioprinting encompass the ability to customize scaffold design, enabling the precise incorporation of pore shape, size, and porosity, as well as the utilization of patient-specific cells to enhance compatibility. However, various challenges should be considered, including the optimization of biomaterials, ensuring adequate cell viability and differentiation, achieving seamless integration with the host tissue, and navigating regulatory attention. Although numerous studies have demonstrated the potential of 3D bioprinting in the rebuilding of such soft tissues, this paper covers various aspects of the bioprinted tissues to provide insights for the future development of repair techniques appropriate for clinical use.

Correlation of maximal nasal septal deviation with deviation at the maxillary insertion

PURPOSE

It is unclear if septal deviation at the insertion points to the nasal cavity is associated with the overall septal deviation. This study aimed to assess septal deviation at the cribriform plate (CP) and maxillary crest (MC) using CT scans and to see if there was any correlation with overall septal deviation.

METHODS

All consecutive CT sinus scans between January 2020 and December 2021 were retrospectively reviewed. Patients were excluded if they had a history of head, nasal or facial trauma, or any previous nasal surgical procedure. Angles between the septum and MC and the septum and CP as well as maximal angle of septal deviation (MSD) were measured.

RESULTS

A total of 70 scans were included in the final analysis. The mean MSD was 8.14°. The mean septal deviation was 0.89° at the CP and 2.02° at the MC. The correlation coefficient between the deviation at the CP and MSD was 0.025 and between the deviation at the MC and MSD was 0.321.

CONCLUSION

Our data reveal a positive correlation between septal deviation at the floor of the nose and overall septal deviation; this was not observed at the septal deviation at the roof. This could be explained due to the inherent tilt in the cribriform plate or by earlier ossification and fixation of the septum during its development at its insertion to the roof, thereby allowing further growth and potential for deviation of the lower part of the septum and its insertion to the floor.

Primary rhinoplasty in patients with bilateral cleft lip: Longitudinal results and comparison between closed and semi-open approaches

BACKGROUND

Although several studies have shown that primary rhinoplasty in patients with cleft lip provides good outcomes with limited effect on nasal growth, the surgical procedure remains to be standardized. The purpose of this study was to evaluate the long-term outcome of primary semi-open rhinoplasty with Tajima reverse-U incision, compared with that of closed rhinoplasty.

METHODS

Consecutive nonsyndromic patients with complete bilateral cleft lip and palate (n = 52) who underwent primary semi-open rhinoplasty between 2001 and 2016 were reviewed. Patients who underwent primary closed rhinoplasty (n = 61) and control group individuals were recruited for comparison. Computer-based standardized measurements of 2D photographs and panel assessments by laypersons were collected and statistically analyzed.

RESULTS

In the comparative analysis at preschool age, semi-open rhinoplasty significantly improved the typical nasal deformities, including transversely oriented wide nostrils, short columella, and de-projected nasal tip, more effectively than closed rhinoplasty. Without major drawbacks, these parameters in the semi-open group were well maintained closer to those in the control group till skeletal maturity. After primary rhinoplasty, 54% of patients in the closed group and 4% in the semi-open group underwent intermediate rhinoplasty at preschool age.

CONCLUSION

This study showed that the patients who underwent primary semi-open rhinoplasty achieved long-term and persistent outcomes that were closer to the normal nasal morphology compared with the patients treated with closed rhinoplasty, while avoiding intermediate rhinoplasty during the preschool to adolescent periods.

Outcome Evaluation of Using Bone-Cartilaginous Units to Correct Deviated Noses in Rhinoplasty

Background: Aesthetic and functional problems related to a deviated nose are challenging to correct with rhinoplasty. Objective: To compare the outcome of rhinoplasty using nasal septal bone-cartilaginous units (BCUs) as measured by pre- and postoperative patient-reported outcomes and photograph analysis. Methods: A retrospective chart review was conducted on rhinoplasty patients who had BCU placed between February 2018 and March 2021. Three-dimensional photographic measurements were assessed before and at least 1 year after surgery using Mirror software. Data on patient satisfaction were collected by the Nasal Obstruction Symptom Evaluation (NOSE) and the Rhinoplasty Outcomes Evaluation (ROE) questionnaires. Statistical analysis was completed with independent t-tests and Wilcoxon signed-rank test. Results: Twenty-eight patients were enrolled with a mean age of 34.52 ± 13.7 years (range 20-77 years) and mostly female (61%). The degree of nasal deviation (from 1/82° ± 1/52° to 0/13° ± 0/45°) and the width of the middle nasal third to palpebral fissure length (from 1/28° ± 0/18° to 1/19° ± 0/19°) significantly changed (p-value <0.001). NOSE and ROE scores also improved significantly postoperation (p-value <0.001). Conclusion: The bone-cartilaginous unit graft was effective in rhinoplasty for nasal deviations and may be considered an option.

Depth-Dependent Strain Model (1D) for Anisotropic Fibrils in Articular Cartilage

The mechanical response of articular cartilage (AC) under compression is anisotropic and depth-dependent. AC is osmotically active, and its intrinsic osmotic swelling pressure is balanced by its collagen fibril network. This mechanism requires the collagen fibers to be under a state of tensile pre-strain. A simple mathematical model is used to explain the depth-dependent strain calculations observed in articular cartilage under 1D axial compression (perpendicular to the articular surface). The collagen fibers are under pre-strain, influenced by proteoglycan concentration (fixed charged density, FCD) and collagen stiffness against swelling stress. The stiffness is introduced in our model as an anisotropic modulus that varies with fibril orientation through tissue depth. The collagen fibers are stiffer to stretching parallel to their length than perpendicular to it; when combined with depth-varying FCD, the model successfully predicts how tissue strains decrease with depth during compression. In summary, this model highlights that the mechanical properties of cartilage depend not only on proteoglycan concentration but also on the intrinsic properties of the pre-strained collagen network. These properties are essential for the proper functioning of articular cartilage.

Second Harmonic Imaging of Nasal, Auricular, and Costal Cartilage

OBJECTIVE

There is little knowledge about the histological organization of facial and costal cartilages in terms of matrix structure and cell morphology. Second harmonic generation (SHG) imaging is a nonlinear imaging technique that capitalizes on signal generation from highly ordered macromolecules such as collagen fibers. The purpose of this study was to use SHG microscopy to image collagen extracellular matrix (ECM) structure, chondrocyte size, and density of these cartilages.

STUDY DESIGN

Experimental.

METHODS

Surgical remnants of septal, lower lateral, rib, and auricular cartilages were collected following surgery, sectioned into 0.5-1 mm thick samples and fixed to facilitate batch process imaging. A Leica TCS SP8 MP Microscope and multiphoton laser were used to image the specimens. Images were analyzed for cell size, cell density, and collagen fiber directionality patterns using ImageJ.

RESULTS

SHG images of septal specimens show mesh-like structure of the ECM. There appears to be a superficial layer, characterized by flattened lacunae and middle zone, marked by circular lacunae clusters, similar to what is observed in articular cartilage. The structure of the ECM depicts a visible orientation perpendicular to the surface of the perichondrium. Cell size and density analysis through ImageJ suggests variety across cartilage types. Directionality analysis indicates that the collagen in the ECM displays preferred direction.

CONCLUSION

This study establishes clear extracellular models of facial and costal cartilages. Limitations include heterogeneous cartilage thickness due to processing difficulties. Further studies include automating the cutting process to increase uniformity of tissue thickness and increasing sample size to further validate results.

LEVEL OF EVIDENCE

2 Laryngoscope, 133:3370-3377, 2023.

Enhanced BMP signaling leads to enlarged nasal cartilage formation in mice

Bone morphogenetic proteins (BMPs) are required for craniofacial bone development. However, it remains elusive how BMP signaling regulates craniofacial cartilage development. To address this question, we utilized a genetic system to enhance BMP signaling via one of BMP type I receptors ALK2 in a chondrocyte-specific manner (hereafter Ca-Alk2:Col2-Cre) in mice. Ca-Alk2:Col2-Cre mice died shortly after birth due to severe craniofacial abnormalities including cleft palate, defective tongue, and shorter mandible formation. Histological analysis revealed that these phenotypes were attributed to the extensive chondrogenesis. Compared with controls, enhanced SOX9 and RUNX2 production were observed in nasal cartilage of Ca-Alk2:Col2-Cre mice. To reveal the mechanisms responsible for enlarged nasal cartilage, we examined Smad-dependent and Smad-independent BMP signaling pathways. While the Smad-independent BMP signaling pathway including p38, ERK, and JNK remained silent, the Smad1/5/9 was highly phosphorylated in Ca-Alk2:Col2-Cre mice. Interestingly, Ca-Alk2:Col2-Cre mice showed enhanced S6 kinase phosphorylation, a readout of mammalian target of rapamycin complex 1 (mTORC1). These findings may suggest that enhanced Smad-dependent BMP signaling positively regulates the mTOR pathway and stimulates chondrocytes toward hypertrophic differentiation, thereby leading to enlarged nasal cartilage formation in mice.

The Effect of Trans-Sutural Distraction Osteogenesis on Nasal Bone, Nasal Septum, and Nasal Airway in the Treatment for Midfacial Hypoplasia in Growing Patients

The purposes of this study were to analyze the effect of trans-sutural distraction osteogenesis (TSDO) on nasal bone, nasal septum, and nasal airway in the treatment of midfacial hypoplasia. A total of 29 growing patients with midfacial hypoplasia who underwent TSDO by a single surgeon were enrolled. The 3-dimensional measurement of nasal bone and nasal septum changes was performed using computed tomography (CT) images obtained preoperatively (T0) and postoperatively (T1). One patient was selected to establish 3-dimensional finite element models to simulate the characteristics of nasal airflow field before and after traction. After traction, the nasal bone moved forward significantly ( P <0.01). The septal deviation angle was lower than that before traction (14.43±4.70 versus 16.86 ±4.59 degrees) ( P <0.01). The length of the anterior and posterior margin of the vomer increased by 21.4% ( P <0.01) and 27.6% ( P <0.01), respectively, after TSDO. The length of the posterior margin of the perpendicular plate of ethmoid increased ( P <0.05). The length of the posterior inferior and the posterior superior margin of the nasal septum cartilage increased ( P <0.01) after traction. The cross-sectional area of nasal airway on the deviated side of nasal septum increased by 23.0% after traction ( P <0.05). The analysis of nasal airflow field showed that the pressure and velocity of nasal airflow and the nasal resistance decreased. In conclusion, TSDO can promote the growth of the midface, especially nasal septum, and increase the nasal space. Furthermore, TSDO is conductive to improve nasal septum deviation and decrease nasal airway resistance.