Cartilage reconstruction in head and neck surgery: Comparison of resorbable polymer scaffolds for tissue engineering of human septal cartilage

Abstract

New cell culture techniques raise the possibility of creating cartilage in vitro with the help of tissue engineering. In this study, we compared two resorbable nonwoven cell scaffolds, a polyglycolic acid/poly-L-lactic acid (PGA/ PLLA) (90/10) copolymer (Ethisorb) and pure PLLA (V 7-2), with different degradation characteristics in their aptitude for cartilage reconstruction. Chondrocytes were isolated enzymatically from human septal cartilage. The single cells were resuspended in agarose and transferred into the polymer scaffolds to create mechanical stability and retain the chondrocyte-specific phenotype. The cell-polymer constructs were then kept in perfusion culture for 1 week prior to subcutaneous transplantation into thymusaplastic nude mice. After 6, 12, and 24 weeks, the specimens were explanted and analyzed histochemically on the presence of collagen (azan staining), proteoglycans (Alcian blue staining), and calcification areas (von Kossa staining). Furthermore, different collagen types (collagen type I, which is found in most tissues, but not in hyaline cartilage matrix; and collagen type II, which is cartilage specific) were differentiated immunohistochemically by the indirect immunoperoxidase technique. Vascular ingrowth was investigated by a factor VIII antibody, which is a endothelial marker. Quantification of several matrix components was performed using the software Photoshop. Significant differences were found between both nonwoven structures concerning matrix synthesis and matrix quality as well as vascular ingrowth. Ethisorb, with a degradation time of approximately 3 weeks in vitro, showed no significant differences from normal human septal cartilage in the amount of collagen types I and II 24 weeks after transplantation. Thin fibrous tissue layers containing blood vessels encapsulated the transplants. V 7-2 constructs, which did not show strong signs of degradation even 24 weeks after transplantation, contained remarkably smaller amounts of cartilage-specific matrix components. At the same time, there was vascular ingrowth even in central parts of the transplants. In conclusion, polymer scaffolds with a short degradation time are suitable materials for the development of cartilage matrix products, while longer stability seems to inhibit matrix synthesis. Thus, in vitro engineering of human cartilage can result in a cartilage-like tissue when appropriate nonwovens are used. Therefore, this method could be the ideal cartilage replacement method without the risk of infection and with the possibility of reconstructing large defects with different configurations.

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

“…11 Moreover, previous human nasoseptal cartilage tissue engineering studies (except for cell pellet cultures) have typically used scaffolds to support cell growth. 7,26,27,29,33,34 Scaffolds can elicit immune response in human patients upon implantation, 14,15 thus warranting the development of scaffold-free approaches. Here, we demonstrated the feasibility of engineering human nasoseptal cartilage directly from a small population of primary cells without a scaffold through bioreactor cultivation.…”

Human Septal Chondrocyte Redifferentiation in Alginate, Polyglycolic Acid Scaffold, and Monolayer Culture

“…Using biodegradable scaffolds, several authors have reported success in fabricating tissue from septal chondrocytes that resembles native cartilage when examined histologically. [2][3][4] Other groups have achieved similar success using auricular chondrocytes to form elastic cartilage. 5,6 Neocartilage grown in previous studies [2][3][4][5][6] has stained positively for extracellular matrix structures found in native cartilage, such as sulfated glycosaminoglycans, collagen type II, and elastin.…”

Degradation behavior of poly(glycerol sebacate)

“…In addition, the scaffold should be bioresorbable and highly biocompatible, with degradation properties that ensure that the structural integrity of the tissue increases at a rate similar to the decrease in the scaffold. [2][3][4][5] Commercially available glycolide and lactide-based (co)polymers are extensively used in tissue engineering applications; however, these materials are poorly suited for engineering soft tissue implants because of limited elastic capabilities. Consequently, significant interest exists to develop biodegradable elastomers that elicit minimal tissue response and have degradation and mechanical prop-erties that can be tailored to match specific tissue requirements.…”