title: Mechanical and biochemical mapping of human auricular cartilage for reliable assessment of tissue-engineered constructs.
abstract: It is key for successful auricular (AUR) cartilage tissue-engineering (TE) to ensure that the engineered cartilage mimics the mechanics of the native tissue. This study provides a spatial map of the mechanical and biochemical properties of human auricular cartilage, thus establishing a benchmark for the evaluation of functional competency in AUR cartilage TE. Stress-relaxation indentation (instantaneous modulus, Ein; maximum stress, σmax; equilibrium modulus, Eeq; relaxation half-life time, t1/2; thickness, h) and biochemical parameters (content of DNA; sulfated-glycosaminoglycan, sGAG; hydroxyproline, HYP; elastin, ELN) of fresh human AUR cartilage were evaluated. Samples were categorized into age groups and according to their harvesting region in the human auricle (for AUR cartilage only). AUR cartilage displayed significantly lower Ein, σmax, Eeq, sGAG content; and significantly higher t1/2, and DNA content than NAS cartilage. Large amounts of ELN were measured in AUR cartilage (>15% ELN content per sample wet mass). No effect of gender was observed for either auricular or nasoseptal samples. For auricular samples, significant differences between age groups for h, sGAG and HYP, and significant regional variations for Ein, σmax, Eeq, t1/2, h, DNA and sGAG were measured. However, only low correlations between mechanical and biochemical parameters were seen (R<0.44). In conclusion, this study established the first comprehensive mechanical and biochemical map of human auricular cartilage. Regional variations in mechanical and biochemical properties were demonstrated in the auricle. This finding highlights the importance of focusing future research on efforts to produce cartilage grafts with spatially tunable mechanics.
authors.affiliation: Institute for Biomechanics, ETH Zürich, Zürich, Switzerland.
authors.forename: Luc
authors.initials: L
authors.lastname: Nimeskern
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
authors.forename: Mieke M
authors.initials: MM
authors.lastname: Pleumeekers
authors.affiliation: Institute for Biomechanics, ETH Zürich, Zürich, Switzerland.
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: Pawson
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
authors.forename: Wendy L M
authors.initials: WL
authors.lastname: Koevoet
authors.affiliation: Institute for Biomechanics, ETH Zürich, Zürich, Switzerland.
authors.forename: Iina
authors.initials: I
authors.lastname: Lehtoviita
authors.affiliation: Department of Otorhinolaryngology and Head and Neck Surgery, University Hospital Zürich, Zürich, Switzerland.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Soyka
authors.affiliation: Department of Otorhinolaryngology and Head and Neck Surgery, University Hospital Zürich, Zürich, Switzerland.
authors.forename: Christof
authors.initials: C
authors.lastname: Röösli
authors.affiliation: Department of Otorhinolaryngology and Head and Neck Surgery, University Hospital Zürich, Zürich, Switzerland.
authors.forename: David
authors.initials: D
authors.lastname: Holzmann
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; Department of Orthopaedics, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
authors.forename: Gerjo J V M
authors.initials: GJ
authors.lastname: van Osch
authors.affiliation: Institute for Biomechanics, ETH Zürich, Zürich, Switzerland.
authors.forename: Ralph
authors.initials: R
authors.lastname: Müller
authors.affiliation: Institute for Biomechanics, ETH Zürich, Zürich, Switzerland. Electronic address: kas@ethz.ch.
authors.forename: Kathryn S
authors.initials: KS
authors.lastname: Stok
mesh_terms: D000328:Adult; D004247:DNA / Q000032:analysis; D004425:Ear Cartilage / Q000737:chemistry / Q000502:physiology / Q000637:transplantation; D004549:Elastin / Q000032:analysis; D005260:Female; D006025:Glycosaminoglycans / Q000032:analysis; D006801:Humans; D006909:Hydroxyproline / Q000032:analysis; D008297:Male; D008875:Middle Aged; D023822:Tissue Engineering; D019737:Transplants; D055815:Young Adult
chemical_list: D006025:Glycosaminoglycans; D004247:DNA; D004549:Elastin; D006909:Hydroxyproline
keywords: Auricle; Biomechanical properties; Ear cartilage; Ear reconstruction; pinna