Age-related changes in the composition and mechanical properties of human nasal cartilage

Nasal cartilage is widely used in reconstructive surgery for the replacement of soft tissue defects and nasal reconstruction procedures. The ability to shape harvested tissue and the performance in the transplant site are related to the mechanical properties of nasal cartilage. Several studies have documented changes in composition and mechanical properties of other cartilages with age, but little is known about these processes in nasal cartilage. In this study, 45 human nasal septum specimens were gathered from patients 15-60 years of age after reconstructive surgery. Samples were cut to 6 mm in diameter and tested in confined compression to determine equilibrium modulus and hydraulic permeability and analyzed for glycosaminoglycan and hydroxyproline content. Equilibrium modulus decreased significantly with increasing donor age (P<0.01) while hydraulic permeability increased significantly (P<0.02). Glycosaminoglycan (GAG) content decreased significantly with age (P<0.05), while hydroxyproline content showed a slight, but not significant, increase with age (P>0.2). These trends are qualitatively similar to those observed in articular cartilage, suggesting the existence of a systemic process of cartilage degradation that is independent of mechanical loading. Further, the relationships between biochemical composition and mechanical properties were age-dependent, with cartilage from patients less than 30 years of age showing greater dependence of equilibrium modulus and hydraulic permeability on GAG and hydroxyproline content. This suggests that changes in matrix organization may accompany changes in tissue composition.