scholarly journals Mammalian cartilage synthesizes both proteoglycan and non-proteoglycan forms of type IX collagen

1991 ◽  
Vol 278 (2) ◽  
pp. 441-445 ◽  
Author(s):  
S Ayad ◽  
A Marriott ◽  
V H Brierley ◽  
M E Grant

Bovine epiphysial cartilage synthesizes both proteoglycan (PG) and non-PG forms of type IX collagen in a ratio of approx. 2:1. The PG form with its attached glycosaminoglycan on the alpha 2(IX) chain is the major form in the medium, whereas both forms are found in the tissue. The results are discussed with regard to cartilage matrix organization.

2001 ◽  
Vol 125 (10) ◽  
pp. 1375-1378
Author(s):  
Alessandro Corsi ◽  
Mara Riminucci ◽  
Larry W. Fisher ◽  
Paolo Bianco

Abstract Achondrogenesis type IB is a lethal osteochondrodysplasia caused by mutations in the diastrophic dysplasia sulfate transporter gene. How these mutations lead to the skeletal phenotype is not known. Histology of plastic-embedded skeletal fetal achondrogenesis type IB samples suggested that interterritorial epiphyseal cartilage matrix was selectively missing. Cartilage was organized in “chondrons” separated by cleft spaces; chondrocyte seriation, longitudinal septa, and, in turn, mineralized cartilaginous septa were absent. Agenesis of interterritorial matrix as the key histologic change was confirmed by immunohistology using specific markers of territorial and interterritorial matrix. Biglycan-enriched territorial matrix was preserved; decorin-enriched interterritorial areas were absent, although immunostaining was observed within chondrocytes. Thus, in achondrogenesis type IB: (1) a complex derangement in cartilage matrix assembly lies downstream of the deficient sulfate transporter activity; (2) the severely impaired decorin deposition participates in the changes in matrix organization with lack of development of normal interterritorial matrix; and (3) this change determines the lack of the necessary structural substrate for proper endochondral bone formation and explains the severe skeletal phenotype.


Author(s):  
H. Clarke Anderson ◽  
Priscilla R. Coulter

Epiphyseal cartilage matrix contains fibrils and particles of at least 5 different types: 1. Banded collagen fibrils, present throughout the matrix, but not seen in the lacunae. 2. Non-periodic fine fibrils <100Å in diameter (Fig. 1), which are most notable in the lacunae, and may represent immature collagen. 3. Electron dense matrix granules (Fig. 1) which are often attached to fine fibrils and collagen fibrils, and probably contain protein-polysaccharide although the possibility of a mineral content has not been excluded. 4. Matrix vesicles (Fig. 2) which show a selective distribution throughout the epiphysis, and may play a role in calcification. 5. Needle-like apatite crystals (Fig. 2).Blocks of formalin-fixed epiphysis from weanling mice were digested with the following agents in 0.1M phosphate buffer: a) 5% ethylenediaminetetraacetate (EDTA) at pH 8.3, b) 0.015% bovine testicular hyaluronidase (Sigma, type IV, 750 units/mg) at pH 5.5, and c) 0.1% collagenase (Worthington, chromatograhically pure, 200 units/mg) at pH 7.4. All digestions were carried out at 37°C overnight. Following digestion tissues were examined by light and electron microscopy to determine changes in the various fibrils and particles of the matrix.


Author(s):  
Douglas R. Keene ◽  
Magaret Fairhurst ◽  
Catherine C. Ridgway ◽  
Lynn Y. Sakai

Matrix microfibrils are present in the connective tissue matrices of all tissues. Following standard TEM processing, they appear in cross section as cylindrical fibrils 8-10 nm in diameter, often associated with amorphous elastin. They are also seen in the absence of amorphous elastin, for example in the shallow papillary layer of skin, and also in cartilage matrix (Figure 1). Negative stain and rotary shadowing studies suggest that microfibrils are composed of laterally associated globular structures connected by fine filamentous strands (“ beaded strings”), and that they are extendable. Immunoelectron microscopy has demonstrated that fibrillin, a 350 Kd glycoprotein, is distributed along all microfibrils with a relaxed periodicity of about 54 nm The gene coding for fibrillin has recently been identified and is defective in the Marfan syndrome.


1995 ◽  
Vol 66 (sup266) ◽  
pp. 71-72 ◽  
Author(s):  
Nik Hauser ◽  
Mats Paulsson ◽  
Dick Heinegård ◽  
Matthias Mörgelin

Sign in / Sign up

Export Citation Format

Share Document