Structural Changes during Development in Bovine Fetal Epiphyseal Cartilage

Buckwalter, Joseph A.; Rosenberg, Lawrence

doi:10.1016/s0174-173x(83)80028-4

Cited by 81 publications

(38 citation statements)

References 23 publications

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“…Interestingly, the size of a proteoglycan aggregate is approximately 90 Å in width as estimated by electron micrography. 35 Here, the data clearly illustrate the impact of hydrogel structure on the diffusion and distribution of proteoglycans in the cell-hydrogel construct. The distribution of collagen in the cell-hydrogel constructs was also examined.…”

Section: Nondegradable Hydrogelsmentioning

confidence: 71%

Hydrogel properties influence ECM production by chondrocytes photoencapsulated in poly(ethylene glycol) hydrogels

Bryant

Anseth

2001

J. Biomed. Mater. Res.

773

685

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When using hydrogel scaffolds for cartilage tissue engineering, two gel properties are particularly important: the equilibrium water content (q, equilibrium swelling ratio) and the compressive modulus, K. In this work, chondrocytes were photoencapsulated in degrading and nondegrading poly(ethylene glycol)-based hydrogels to assess extracellular matrix (ECM) formation as a function of these gel properties. In nondegrading gels, the glycosaminoglycan (GAG) content was not significantly different in gels when q was varied from 4.2 to 9.3 after 2 and 4 weeks in vitro. However, gels with a q of 9.3 allowed GAGs to diffuse throughout the gels homogenously, but a q < or = 5.2 resulted in localization of GAGs pericellularly. Interestingly, in the moderately crosslinked gels with a K of 360 kPa, an increase in type II collagen synthesis was observed compared with gels with a higher (960 kPa) and lower (30 kPa) K after 4 weeks. With the incorporation of degradable linkages into the network, gel properties with an initially high K (350 kPa) and final high q (7.9) were obtained, which allowed for increased type II collagen synthesis coupled with a homogenous distribution of GAGs. Thus, a critical balance exists between gel swelling, mechanics, and degradation in forming a functional ECM.

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Section: Nondegradable Hydrogelsmentioning

confidence: 71%

Hydrogel properties influence ECM production by chondrocytes photoencapsulated in poly(ethylene glycol) hydrogels

Bryant

Anseth

2001

J. Biomed. Mater. Res.

773

685

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“…The CHAPS-NC had branched chains of aggregates in structures resembling the high molecular weight sulfated proteoglycans (52). The formation of these aggregates may be related to the high molecular weight band seen in SDS-PAGE analysis of the CHAPS core (Fig.…”

Section: Discussionmentioning

confidence: 92%

Physicochemical Characterization of the Nucleational Core of Matrix Vesicles

Genge

Dunkelberger

et al. 1997

Journal of Biological Chemistry

139

154

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While previous studies revealed that matrix vesicles (MV) contain a nucleational core (NC) that converts to apatite when incubated with synthetic cartilage lymph, the initial mineral phase present in MV is not well characterized. This study explored the physicochemical nature of this Ca 2؉ and P i -rich NC. MV, isolated from growth plate cartilage, were analyzed directly by solidstate 31 P NMR, or incubated with hydrazine or NaOCl to remove organic constituents. Other samples of MV were subjected to sequential treatments with enzymes, salt solutions, and detergents to expose the NC. We examined the NC using transmission electron microscopy, energy-dispersive analysis with x-rays, and electron and x-ray diffraction, Fourier transform-infrared spectroscopy, high performance thin-layer chromatographic analysis, and SDS-polyacrylamide gel electrophoresis. We found that most of the MV proteins and lipids could be removed without destroying the NC; however, NaOCl treatment annihilated its activity. SDS-polyacrylamide gel electrophoresis showed that annexin V, a phosphatidylserine (PS)-dependent Ca 2؉ -binding protein, was the major protein in the NC; high performance thin-layer chromatographic analysis revealed that the detergents removed the majority of the polar lipids, but left significant free cholesterol and fatty acids, and small but critical amounts of PS. Transmission electron microscopy showed that the NC was composed of clusters of ϳ1.0 nm subunits, which energy-dispersive analysis with x-rays revealed contained Ca and P i with a Ca/P ratio of 1.06 ؎ 0.01. Electron diffraction, x-ray diffraction, and Fourier transform-infrared analysis all indicated that the NC was noncrystalline.

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“…It has been suggested [1] that proteoglycan modification is required for growth plate mineralization and that removal of the proteoglycans facilitates the growth and proliferation of mineral crystals. Thus the failure to produce a temporal increase in mineral accretion when stromelysin and other metalloproteases were inhibited, supports this hypothesis.…”

Section: Discussionmentioning

confidence: 99%

“…Biochem. 64:632-643. r 1997 Wiley-Liss, Inc.Key words: calcification; proteoglycans; chondrocyte culture; micro-mass culture; cartilage calcification Within the epiphyseal growth plate, the large aggregating chondroitin sulfate proteoglycans of cartilage (aggrecan) change in physical properties as calcification commences [1,2]. Whether this change is essential for growth plate calcification or coincident to this process is in debate.…”

mentioning

confidence: 99%

Effects of proteoglycan modification on mineral formation in a differentiating chick limb-bud mesenchymal cell culture system

et al. 1997

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In the presence of 4 mM inorganic phosphate, differentiating chick limb-bud mesenchymal cells plated in micromass cultures form a mineralized matrix resembling that of chick calcified cartilage. To test the hypothesis that cartilage proteoglycans are inhibitors of cell mediated mineralization, the synthesis, content, and turnover of proteoglycans were altered in this system, and the extent of mineralization and properties of the mineral crystals examined. In all cases where the proteoglycan synthesis or proteoglycans present were modified to provide fewer or smaller molecules, mineralization was enhanced. Specifically, when proteoglycan synthesis was blocked by treatment with 10(-10) M retinoic acid, extensive mineral deposition occurred on a matrix devoid of both proteoglycans and cartilage nodules. The crystals, which formed rapidly, were relatively large in size based on analysis by X-ray diffraction or FT-1R microspectroscopy, and were more abundant than in controls. When 2.5 or 5 mM xylosides were used to cause the synthesis of smaller proteoglycans, the extent of mineral accretion was also increased relative to controls; however, the matrix was less affected, and the extent of mineral deposition and the size of the crystals were not as markedly altered as in the case of retinoic acid. Modification of existing proteoglycans by either chondroinase ABC or hyaluronidase treatment similarly resulted in increased mineral accretion (based on 45Ca uptake or total Ca uptake) relative to cultures in which the proteoglycan content was not manipulated. Crystals were more abundant and larger than in control mineralizing cultures. In contrast, when proteoglycan degradation by metalloproteases was inhibited by metal chelation with o-phenanthroline, the Ca accretion at early time points was increased, but as mineralization progressed, Ca accumulation decreased. These data provide evidence that in this culture system, proteoglycans are inhibitors of mineralization.

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Structural Changes during Development in Bovine Fetal Epiphyseal Cartilage

Cited by 81 publications

References 23 publications

Hydrogel properties influence ECM production by chondrocytes photoencapsulated in poly(ethylene glycol) hydrogels

Hydrogel properties influence ECM production by chondrocytes photoencapsulated in poly(ethylene glycol) hydrogels

Physicochemical Characterization of the Nucleational Core of Matrix Vesicles

Effects of proteoglycan modification on mineral formation in a differentiating chick limb-bud mesenchymal cell culture system

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