Investigations of the Composition-Function Relationships in Normal, Degraded, and Engineered Articular Cartilage Using Epic-Microcomputed Tomography

Articular cartilage provides a low-friction surface during normal joint motion and distributes forces to the underlying bone. The extracellular matrix composition (ECM) of healthy cartilage has previously been shown to be an excellent predictor of its mechanical properties. Changes in ECM composition and loss of mechanical function are known to occur with degenerative conditions such as osteoarthritis. Identifying differences in the composition-function relationships of articular cartilage under different anabolic, catabolic, and homeostatic conditions may therefore be a useful approach for identifying factors (e.g. ECM content, distribution, and structure) which are critical to mechanical function. In addition, diagnostic tools capable of monitoring changes in the articular cartilage ECM may increase our understanding of the effects of ECM changes on composition-functions relationships.

The goals of this work were to investigate composition-function relationships in healthy, degraded, and engineered articular cartilage and to develop a µCT-based approach to analyze changes in matrix composition and morphology in articular cartilage. In healthy cartilage explants, compressive and shear properties were dependent on both sGAG and collagen content. In contrast, the compressive properties of IL-1-stimulated cartilage were dependent on sGAG but not collagen content. To assess changes in sGAG content, EPIC-µCT, a 3D contrast-enhanced microcomputed tomography technique was developed. EPIC-µCT attenuation was found to be an excellent predictor of sGAG content in IL-1-stimulated cartilage explants and engineered cartilage. In addition, analytical approaches were developed to use EPIC-µCT for the in situ analysis of cartilage morphology. EPIC-µCT was also used to analyze spatial differences in sGAG accumulation in bilayer engineered cartilage for comparison with the local strain profile. This work underscores the significance of ECM composition and structure in regulating cartilage mechanical properties and validates the use of EPIC-µCT as a diagnostic for monitoring sGAG content and potentially for assessing mechanical function in models of degeneration and regeneration.

Year	Entry
2003	Ng L, Grodzinsky AJ, Patwari P, Sandy J, Plaas A, Ortiz C. Individual cartilage aggrecan macromolecules and their constituent glycosaminoglycans visualized via atomic force microscopy. J Struct Biol. September 2003;143(3):242-257.
2002	Wang CC-B, Guo XE, Sun D, Mow VC, Ateshian GA, Hung CT. The functional environment of chondrocytes within cartilage subjected to compressive loading: a theoretical and experimental approach. Biorheology. 2002;39(1-2):11-25.
1994	Guilak F, Meyer BC, Ratcliffe A, Mow VC. The effects of matrix compression on proteoglycan metabolism in articular cartilage explants. Osteoarthritis Cartilage. June 1994;2(2):91-101.
1979	Maroudas A. Physicochemical properties of articular cartilage. In: Freeman MAR, ed. Adult Articular Cartilage. 2nd ed. Kent, England: Pitman Medical; 1979:215-290.
2001	Williamson AK, Chen AC, Sah RL. Compressive properties and function—composition relationships of developing bovine articular cartilage. J Orthop Res. November 2001;19(6):1113-1121.
2003	Williamson AK, Chen AC, Masuda K, Thonar EJ, Sah RL. Tensile mechanical properties of bovine articular cartilage: variations with growth and relationships to collagen network components. J Orthop Res. September 2003;21(5):872-880.
2001	Chen AC, Bae WC, Schinagl RM, Sah RL. Depth- and strain-dependent mechanical and electromechanical properties of full-thickness bovine articular cartilage in confined compression. J Biomech. January 2001;34(1):1-12.
1989	Sah RL-Y, Kim Y-J, Doong J-YH, Grodzinsky AJ, Plass AHK, Sandy JD. Biosynthetic response of cartilage explants to dynamic compression. J Orthop Res. 1989;7(5):619-636.
2005	Jadin KD, Wong BL, Bae WC, Li KW, Williamson AK, Schumacher BL, Price JH, Sah RL. Depth-varying density and organization of chondrocytes in immature and mature bovine articular cartilage assessed by 3D imaging and analysis. J Histochem Cytochem. September 2005;53(9):1109-1119.
1994	Guilak F, Ratcliffe A, Lane N, Rosenwasser MP, Mow VC. Mechanical and biochemical changes in the superficial zone of articular cartilage in canine experimental osteoarthritis. J Orthop Res. July 1994;12(4):474-484.
2001	Poole AR, Kojima T, Yasuda T, Mwale F, Kobayashi M, Laverty S. Composition and structure of articular cartilage: a template for tissue repair. Clin Orthop Relat Res. October 2001;391(suppl):S26-S33.
1994	Setton LA, Mow VC, Müller FJ, Pita JC, Howell DS. Mechanical properties of canine articular cartilage are significantly altered following transection of the anterior cruciate ligament. J Orthop Res. July 1994;12(4):451-463.
1981	Maroudas A, Bannon C. Measurement of swelling pressure in cartilage and comparison with the osmotic pressure of constituent proteoglycans. Biorheology. 1981;18:619-632.
1998	Basser PJ, Schneiderman R, Bank RA, Wachtel E, Maroudas A. Mechanical properties of the collagen network in human articular cartilage as measured by osmotic stress technique. Arch Biochem Biophys. March 15, 1998;351(2):207-219.
1995	Buschmann MD, Grodzinsky AJ. A molecular model of proteoglycan-associated electrostatic forces in cartilage mechanics. J Biomech Eng. May 1995;117(2):179-192.
2005	Yeni YN, Christopherson GT, Dong XN, Kim D-G, Fyhrie DP. Effect of microcomputed tomography voxel size on the finite element model accuracy for human cancellous bone. J Biomech Eng. February 2005;127(1):1-8.
2000	Treppo S, Koepp H, Quan EC, Cole AA, Kuettner KE, Grodzinsky AJ. Comparison of biomechanical and biochemical properties of cartilage from human knee and ankle pairs. J Orthop Res. September 2000;18(5):739-748.
1998	Bank RA, Bayliss MT, Lafeber FPJG, Maroudas A, Tekoppele JM. Ageing and zonal variation in post-translational modification of collagen in normal human articular cartilage: the age-related increase in non-enzymatic glycation affects biomechanical properties of cartilage. Biochem J. February 15, 1998;3301(1):345-351.
2001	Quinn TM, Morel V, Meister JJ. Static compression of articular cartilage can reduce solute diffusivity and partitioning: implications for the chondrocyte biological response. J Biomech. November 2001;34(11):1463-1469.
1991	Kempson GE. Age-related changes in the tensile properties of human articular cartilage: a comparative study between the femoral head of the hip joint and the talus of the ankle joint. Biochim Biophys Acta. October 31, 1991;1075(3):223-230.
2000	Loening AM, James IE, Levenston ME, Badger AM, Frank EH, Kurz B, Nuttall ME, Hung H-H, Blake SM, Grodzinsky AJ, Lark MW. Injurious mechanical compression of bovine articular cartilage induces chondrocyte apoptosis. Arch Biochem Biophys. September 15, 2000;381(2):205-212.
1984	Armstrong CG, Lai WM, Mow VC. An analysis of the unconfined compression of articular cartilage. J Biomech Eng. May 1984;106(2):165-173.
1961	Woessner JF Jr. The determination of hydroxyproline in tissue and protein samples containing small proportions of this imino acid. Arch Biochem Biophys. May 1961;93(2):440-447.
1973	Kempson GE, Muir H, Pollard C, Tuke M. The tensile properties of the cartilage of human femoral condyles related to the content of collagen and glycosaminoglycans. Biochim Biophys Acta. February 28, 1973;297(2):456-472.
2002	Thibault M, Poole AR, Buschmann MD. Cyclic compression of cartilage/bone explants in vitro leads to physical weakening, mechanical breakdown of collagen and release of matrix fragments. J Orthop Res. November 2002;20(6):1265-1273.
1982	Farndale RW, Sayers CA, Barrett AJ. A direct spectrophotometric microassay for sulfated glycosaminoglycans in cartilage cultures. Connect Tissue Res. 1982;9(4):247-248.
1999	Chen C-T, Burton-Wurster N, Lust G, Bank RA, Tekoppele JM. Compositional and metabolic changes in damaged cartilage are peak-stress, stress-rate, and loading-duration dependent. J Orthop Res. November 1999;17(6):870-879.
2005	Qiu S, Rao DS, Fyhrie DP, Palnitkar S, Parfitt AM. The morphological association between microcracks and osteocyte lacunae in human cortical bone. Bone. July 2005;37(1):10-15.
2000	Ding M. Age variations in the properties of human tibial trabecular bone and cartilage. Acta Orthop Scand. 2000;71(suppl 292):1-45.
1999	Vunjak-Novakovic G, Martin I, Obradovic B, Treppo S, Grodzinsky AJ, Langer R, Freed LE. Bioreactor cultivation conditions modulate the composition and mechanical properties of tissue-engineered cartilage. J Orthop Res. January 1999;17(1):130-138.
2006	Kelly T-AN, Ng KW, Wang CC-B, Ateshian GA, Hung CT. Spatial and temporal development of chondrocyte-seeded agarose constructs in free-swelling and dynamically loaded cultures. J Biomech. 2006;39(8):1489-1497.
2004	Vanderploeg EJ, Imler SM, Brodkin KR, Garcı́a AJ, Levenston ME. Oscillatory tension differentially modulates matrix metabolism and cytoskeletal organization in chondrocytes and fibrochondrocytes. J Biomech. December 2004;37(12):1941-1952.
2002	Korhonen RK, Laasanen MS, Töyräs J, Rieppo J, Hirvonen J, Helminen HJ, Jurvelin JS. Comparison of the equilibrium response of articular cartilage in unconfined compression, confined compression and indentation. J Biomech. July 2002;35(7):903-909.
2004	Duvall CL, Taylor WR, Weiss D, Guldberg RE. Quantitative microcomputed tomography analysis of collateral vessel development after ischemic injury. Am J Physiol Heart Circ Physiol. July 2004;287(1):H302-H310.
2003	Park S, Krishnan R, Nicoll SB, Ateshian GA. Cartilage interstitial fluid load support in unconfined compression. J Biomech. December 2003;36(12):1785-1796.
2007	Klein TJ, Chaudhry M, Bae WC, Sah RL. Depth-dependent biomechanical and biochemical properties of fetal, newborn, and tissue-engineered articular cartilage. J Biomech. January 2007;40(1):182-190.
2000	LeRoux MA, Arokoski J, Vail TP, Guilak F, Hyttinen MM, Kiviranta I, Setton LA. Simultaneous changes in the mechanical properties, quantitative collagen organization, and proteoglycan concentration of articular cartilage following canine meniscectomy. J Orthop Res. May 2000;18(3):383-392.
1993	Zhu W, Mow VC, Koob TJ, Eyre DR. Viscoelastic shear properties of articular cartilage and the effects of glycosidase treatments. J Orthop Res. November 1993;11(6):771-781.
2003	Lin ASP, Barrows TH, Cartmell SH, Guldberg RE. Microarchitectural and mechanical characterization of oriented porous polymer scaffolds. Biomaterials. February 2003;24(3):481-489.
2001	Kurz B, Jin M, Patwari P, Cheng DM, Lark MW, Grodzinsky AJ. Biosynthetic response and mechanical properties of articular cartilage after injurious compression. J Orthop Res. 2001;19(6):1140-1146.
2004	Park S, Hung CT, Ateshian GA. Mechanical response of bovine articular cartilage under dynamic unconfined compression loading at physiological stress levels. Osteoarthritis Cartilage. January 2004;12(1):65-73.
1997	Schinagl RM, Gurskis D, Chen AC, Sah RL. Depth-dependent confined compression modulus of full-thickness bovine articular cartilage. J Orthop Res. July 1997;15(4):499-506.
2002	Hunter CJ, Imler SM, Malaviya P, Nerem RM, Levenston ME. Mechanical compression alters gene expression and extracellular matrix synthesis by chondrocytes cultured in collagen I gels. Biomaterials. February 15, 2002;23(4):1249-1259.

Year

Entry

2003

Ng L, Grodzinsky AJ, Patwari P, Sandy J, Plaas A, Ortiz C. Individual cartilage aggrecan macromolecules and their constituent glycosaminoglycans visualized via atomic force microscopy. J Struct Biol. September 2003;143(3):242-257.

2002

Wang CC-B, Guo XE, Sun D, Mow VC, Ateshian GA, Hung CT. The functional environment of chondrocytes within cartilage subjected to compressive loading: a theoretical and experimental approach. Biorheology. 2002;39(1-2):11-25.

1994

Guilak F, Meyer BC, Ratcliffe A, Mow VC. The effects of matrix compression on proteoglycan metabolism in articular cartilage explants. Osteoarthritis Cartilage. June 1994;2(2):91-101.

1979

Maroudas A. Physicochemical properties of articular cartilage. In: Freeman MAR, ed. Adult Articular Cartilage. 2nd ed. Kent, England: Pitman Medical; 1979:215-290.

2001

Williamson AK, Chen AC, Sah RL. Compressive properties and function—composition relationships of developing bovine articular cartilage. J Orthop Res. November 2001;19(6):1113-1121.