Development of a Method for Scaffold-Free Elastic Cartilage Creation.

Microtia is a congenital aplasia of the auricular cartilage. Conventionally, autologous costal cartilage grafts are collected and shaped for transplantation. However, in this method, excessive invasion occurs due to limitations in the costal cartilage collection. Due to deformation over time after transplantation of the shaped graft, problems with long-term morphological maintenance exist. Additionally, the lack of elasticity with costal cartilage grafts is worth mentioning, as costal cartilage is a type of hyaline cartilage. Medical plastic materials have been transplanted as alternatives to costal cartilage, but transplant rejection and deformation over time are inevitable. It is imperative to create tissues for transplantation using cells of biological origin. Hence, cartilage tissues were developed using a biodegradable scaffold material. However, such materials suffer from transplant rejection and biodegradation, causing the transplanted cartilage tissue to deform due to a lack of elasticity. To address this problem, we established a method for creating elastic cartilage tissue for transplantation with autologous cells without using scaffold materials. Chondrocyte progenitor cells were collected from perichondrial tissue of the ear cartilage. By using a multilayer culture and a three-dimensional rotating suspension culture vessel system, we succeeded in creating scaffold-free elastic cartilage from cartilage progenitor cells.

Uso de fáscia peitoral maior em preenchimento de dorso nasal: relato de caso / Use of pectoralis major fascia in dorsal nasal augmentation: case report

O aumento do dorso nasal nas rinoplastias é foco de estudo de diversos trabalhos que buscam as melhores fontes de enxerto e técnicas cirúrgicas. A utilização de cartilagem já é consagrada para este fim, a partir do septo nasal, da concha auricular ou dos arcos costais. Nos últimos anos, têm-se buscado meios para reduzir a palpabilidade e dispersibilidade dos enxertos cartilaginosos. Assim, são descritos materiais sintéticos, como o SURGICEL®; e, autólogos, representados pelas fáscias. A fáscia temporal é mais amplamente utilizada, porém requer uma nova incisão cirúrgica, aumentando o tempo e a morbidade da cirurgia. É também descrito o uso de fáscia lata e fáscia reto abdominal, comparativamente mais espessas e menos flexíveis. Em muitos casos de rinoplastia fazse necessária a retirada da cartilagem costal, o que permite a coleta de fáscia do músculo peitoral maior pela mesma incisão cirúrgica. Dessa forma, descrevemos a utilização da fáscia do músculo peitoral maior envolvendo cartilagem costal picada, em uma rinoplastia estruturada com aumento do dorso.

Increasing the nasal dorsum in rhinoplasty is the focus of several studies that seek the best graft sources and surgical techniques. The use of cartilage from the nasal septum, ear shell, or costal arches is already established for this purpose. In recent years, methods have been sought to reduce the palpability and dispersibility of cartilaginous grafts. Thus, synthetic materials such as SURGICEL® and autologous materials such as fascia have been explored. Temporal fascia are more widely used but require a new surgical incision, increasing surgical time and morbidity. Also described is the use of fascia lata and rectus abdominis fascia, which are comparatively thicker and less flexible. In many rhinoplasty procedures, it is necessary to remove the costal cartilage, which allows the collection of fascia from the major chest muscles through the same surgical incision. Thus, we describe the use of major chest muscle fascia and chopped costal cartilage in structured rhinoplasty to increase the dorsum.

Histological study of costal cartilage after transplantation and reasons for avoidance of postoperative resorption and retention of cartilage structure in rats.

BACKGROUND: Limited information is available on the biological status of transplanted cartilage from which the perichondrium has been removed. This article describes the histological and three-dimensional structural picture of cartilage, using green fluorescent protein (GFP) transgenic rats and normal wild rats. METHODS: Three sections of costal cartilage were harvested from 10-week-old wild rats. One section was used as a specimen while two were subcutaneously collected from the dorsal region of 10-week-old GFP rats at 4 and 8 weeks post-transplant. The experiment was performed in two randomized groups. The perichondrium was removed from transplanted cartilage in the first group and perichondrium of transplanted cartilage remained intact in the second group. Histology and focused ion beam/scanning electron microscope (FIB/SEM) tomography were used to evaluate the transplanted cartilage. RESULTS: All 40 transplanted sections were harvested and no infections, exposure or qualitative change of cartilage matrix were seen following transplant. Histological analyses showed that the surface layer of the GFP-negative transplanted cartilage was replaced with GFP-positive chondrocytes 8 weeks post-transplant in the first group. A three-dimensional layer of perichondrium-like tissue reconstructed around the cartilage at 8 weeks was confirmed, resembling normal perichondrium. However, the GFP-positive chondrocytes were not replaced in the second group. CONCLUSIONS: The cell renewal of chondrocytes is necessary for subcutaneously transplanted cartilage to maintain its tissue composition over a long period of time. The histological and ultrastructural analyses revealed that cells from recipient tissue generated new chondrocytes even when cartilage was implanted after removing the perichondrium.

Characterization of costal cartilage and its suitability as a cell source for articular cartilage tissue engineering.

Costal cartilage is a promising donor source of chondrocytes to alleviate cell scarcity in articular cartilage tissue engineering. Limited knowledge exists, however, on costal cartilage characteristics. This study describes the characterization of costal cartilage and articular cartilage properties and compares neocartilage engineered with costal chondrocytes to native articular cartilage, all within a sheep model. Specifically, we (a) quantitatively characterized the properties of costal cartilage in comparison to patellofemoral articular cartilage, and (b) evaluated the quality of neocartilage derived from costal chondrocytes for potential use in articular cartilage regeneration. Ovine costal and articular cartilages from various topographical locations were characterized mechanically, biochemically, and histologically. Costal cartilage was stiffer in compression but softer and weaker in tension than articular cartilage. These differences were attributed to high amounts of glycosaminoglycans and mineralization and a low amount of collagen in costal cartilage. Compared to articular cartilage, costal cartilage was more densely populated with chondrocytes, rendering it an excellent chondrocyte source. In terms of tissue engineering, using the self-assembling process, costal chondrocytes formed articular cartilage-like neocartilage. Quantitatively compared via a functionality index, neocartilage achieved 55% of the medial condyle cartilage mechanical and biochemical properties. This characterization study highlighted the differences between costal and articular cartilages in native forms and demonstrated that costal cartilage is a valuable source of chondrocytes suitable for articular cartilage regeneration strategies.

Cell yield, chondrogenic potential, and regenerated cartilage type of chondrocytes derived from ear, nasoseptal, and costal cartilage.

Functional reconstruction of large cartilage defects in subcutaneous sites remains clinically challenging because of limited donor cartilage. Tissue engineering is a promising and widely accepted strategy for cartilage regeneration. To date, however, this strategy has not achieved a significant breakthrough in clinical translation owing to a lack of detailed preclinical data on cell yield and functionality of clinically applicable chondrocytes. To address this issue, the current study investigated the initial cell yield, proliferative potential, chondrogenic capacity, and regenerated cartilage type of human chondrocytes derived from auricular, nasoseptal, and costal cartilage using a scaffold-free cartilage regeneration model (cartilage sheet). Chondrocytes from all sources exhibited high sensitivity to basic fibroblast growth factor within 8 passages. Nasoseptal chondrocytes presented the strongest proliferation rate, whereas auricular chondrocytes obtained the highest total cell amount using comparable cartilage sample weights. Importantly, all chondrocytes at fifth passage showed strong chondrogenic capacity both in vitro and in the subcutaneous environment of nude mice. Although some significant differences in histological structure, cartilage matrix content and cartilage type specific proteins were observed between the in vitro engineered cartilage and original tissue; the in vivo regenerated cartilage showed mature cartilage features with high similarity to their original native tissue, except for minor matrix changes influenced by the in vivo environment. The current study provides detailed preclinical data for choice of chondrocyte source and thus promotes the clinical translation of cartilage regeneration approach.

Deletion of IFT80 Impairs Epiphyseal and Articular Cartilage Formation Due to Disruption of Chondrocyte Differentiation.

Intraflagellar transport proteins (IFT) play important roles in cilia formation and organ development. Partial loss of IFT80 function leads Jeune asphyxiating thoracic dystrophy (JATD) or short-rib polydactyly (SRP) syndrome type III, displaying narrow thoracic cavity and multiple cartilage anomalies. However, it is unknown how IFT80 regulates cartilage formation. To define the role and mechanism of IFT80 in chondrocyte function and cartilage formation, we generated a Col2α1; IFT80f/f mouse model by crossing IFT80f/f mice with inducible Col2α1-CreER mice, and deleted IFT80 in chondrocyte lineage by injection of tamoxifen into the mice in embryonic or postnatal stage. Loss of IFT80 in the embryonic stage resulted in short limbs at birth. Histological studies showed that IFT80-deficient mice have shortened cartilage with marked changes in cellular morphology and organization in the resting, proliferative, pre-hypertrophic, and hypertrophic zones. Moreover, deletion of IFT80 in the postnatal stage led to mouse stunted growth with shortened growth plate but thickened articular cartilage. Defects of ciliogenesis were found in the cartilage of IFT80-deficient mice and primary IFT80-deficient chondrocytes. Further study showed that chondrogenic differentiation was significantly inhibited in IFT80-deficient mice due to reduced hedgehog (Hh) signaling and increased Wnt signaling activities. These findings demonstrate that loss of IFT80 blocks chondrocyte differentiation by disruption of ciliogenesis and alteration of Hh and Wnt signaling transduction, which in turn alters epiphyseal and articular cartilage formation.