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Results for “Cartilage maturation”

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At least 19 recordsLinked to original sources
PubMed1989

Inhibitory effect of mature cartilage on perichondrial neochondrogenesis.

The perichondrium adhering to mature cartilage is not active, but that separated from cartilage is highly chondrogenic. Cartilage formation from isolated perichondrium does not last forever, and perichondrium soon becomes inactive. What activates or inactivates the perichondrium. The authors investigated the effect of mature cartilage on the cartilage formation from perichondrial graft material. The results showed that mature cartilage attached to the perichondrium inhibited neochondrogenesis. The phenomenon that cartilage--a product of chondrogenesis--inhibits neochondrogenesis of perichondrium can be called negative feedback.

Animals↗
PubMed2026

Mapping articular cartilage maturation across postnatal development by proteomics.

OBJECTIVE: Articular cartilage has a specialised extracellular matrix that provides tensile strength and resistance to compression, but repair capacity is limited. Matrix remodelling during growth is essential for long-term tissue function, yet the underlying protein-level adaptations remain poorly characterised in large-animal models relevant to human joint biology. DESIGN: Using non-targeted, label-free mass spectrometry-based proteomics, we profiled full-thickness articular cartilage from goats across seven postnatal ages from neonatal to adult (n = 3 per age). Cartilage proteins were extracted using guanidine-based solubilisation and analysed by mass spectrometry. Selected proteins were further examined by immunohistochemistry. RESULTS: We identified 799 proteins across the seven ages, of which 157 matrisome components grouped into six categories. Development was associated with increased abundance of proteins involved in matrix organisation and stabilisation, including COL6A1, LOX, TIMP3 and CILP. Enrichment analysis revealed a shift from collagen biosynthesis and fibrillogenesis in early postnatal cartilage to elastic fibre organisation, integrin-matrix interactions and glycosaminoglycan metabolism in mature tissue, consistent with transition from matrix assembly to maintenance. Lysozyme increased with age, suggesting a structural role that warrants further study. Several proteins enriched in mature cartilage, including CILP, HTRA1, FN1 and SPP1, have also been implicated in osteoarthritis, suggesting that some molecular features of mature ECM maintenance are shared with diseased tissue. Immunohistochemistry confirmed stable COL2 localisation, loss of deep-zone COL10 staining with maturation and emergence of superficial PRG4 expression in adult cartilage. CONCLUSIONS: Our findings define the proteomic trajectory of cartilage maturation and provide a molecular reference for joint development and matrix ageing.

Animals↗
PubMed2001

Differences in repair responses between immature and mature cartilage.

Cartilage has a poor reparative capacity although it is unclear as to what extent this may be dependent on age or maturation. In the current study, the cellular responses of chondrocytes to experimental wounding in vitro using embryonic, immature, and mature cartilage have been compared. In all cases, the response was consistent (a combination of cell death that included apoptosis and proliferation). The speed of response varied in terms of cell death with embryonic cartilage showing the most rapid response and mature cartilage showing the slowest response. Intrinsic repair as assessed by the ability to heal the lesion was not detected in any of the culture systems used. It was concluded that the poor repair potential of cartilage is not maturation dependent in the systems studied.

Animals↗
PubMed2000

Analysis of cartilage maturation using micromass cultures of primary chondrocytes.

A micromass culture (MM-C) system of primary immature chondrocytes for functional analysis of soluble factors involved in the maturation step of cartilage was previously developed. Ectopically expressed BMP-2 was shown to induce the expression of the Ihh and Noggin genes. Here it is demonstrated that, upon longer culture, secreted bone morphogenetic protein-2 (BMP-2) further promotes the maturation step as judged by the induction of type X collagen and BMP-6 expression, which are known to be detectable in the later phase of cartilage maturation. Induction of all of these genes by secreted BMP-2 was not inhibited by ectopic expression of parathyroid hormone-related peptide (PTHrP) induced by retrovirus vector infection, although the same virus vector showed strong inhibitory effects on the expression of type X collagen gene or alkaline phosphatase activity in mature chondrocytes. These results suggest that the maturation-promoting activity exhibited by BMP-2 is dominant over the suppressive effect of PTHrP in immature chondrocytes. When the BMP-6 gene was introduced into the same virus vector as that used for BMP-2, it induced the same sets of genes (Ihh, Noggin, type X collagen and endogenous BMP-6) as BMP-2 did. These results also suggest that BMP-6 would autonomously maintain and/or promote a later stage of chondrocytic maturation.

Animals↗
PubMed1982

The penetration of misonidazole into a mature structural cartilage.

Mature cartilage may be expected to contain populations of hypoxic cells as a result of the tissues lack of direct vascularization and structure; it may therefore be at risk from possible radiosensitization. The hypoxic-cell radiosensitizing drug misonidazole Ro-07-0582 (MISO) was administered i.v. to mature New Zealand White rabbits at a dose of 100 mg/kg, and the resulting drug concentrations in both blood and ear-cartilage samples measured by HPLC. Samples were taken at regular intervals up to 4 h after administration of MISO. Blood concentrations of MISO rose rapidly to 240 microgram/ml within 5 min of administration, before falling steadily, with a t1/2 of 45 min. Cartilage levels reached a peak of 70% of the blood levels approximately 30 min after administration. The levels of MISO then fell, with a t1/2 of 44 min.

Animals↗
PubMed2006

Effects of TGF-beta1 and triiodothyronine on cartilage maturation: in vitro analysis using long-term high-density micromass cultures of chick embryonic limb mesenchymal cells.

Endochondral ossification is initiated by differentiation of mesenchymal cells into chondrocytes, which produce a cartilaginous matrix, proliferate, mature, and undergo hypertrophy, followed by matrix calcification, and substitution of cartilage by bone. A number of hormones and growth factors have been implicated in this process. Using in vitro, long-term, high-density, micromass cultures of chick embryonic mesenchyme, that recapitulate the process of chondrogenesis, chondrocyte maturation, and hypertrophy, we have investigated the importance of a balance between proliferation and apoptosis in cartilage maturation, focusing specifically on the effects of transforming growth factor-beta1 (TGF-beta1) and the thyroid hormone, triiodothyronine (T3). Our results showed that TGF-beta1 stimulates proliferation, by week 2 of culture, and T3 inhibits proliferation by week 3. Cell size increases in cultures treated with T3. Collagen type X is expressed in all culture, and delay in matrix deposition is seen only in the cultures treated with TGF-beta1. T3 stimulates alkaline phosphatase activity, but not calcification. T3 enhances apoptosis, as seen by TUNEL staining, and internucleosomal DNA fragmentation. The results support the roles of T3 and TGF-beta in cartilage maturation, i.e., TGF-beta stimulates proliferation and suppresses hypertrophy, while T3 stimulates hypertrophy and apoptosis.

Alkaline Phosphatase↗
PubMed2001

Assessment of rat articular cartilage maturation using 50-MHz quantitative ultrasonography.

OBJECTIVE: The objective was to assess the relationship between maturation-related structural changes of articular cartilage and variations of acoustic parameters estimated using high frequency ultrasonography. DESIGN: Patellae taken from 48 immature Wistar male rats and divided into six age groups (from five to 11 weeks old) were explored in vitro using 50-MHz scanning acoustic microscopy, then assessed by histology for the analysis of the cartilage cell distribution and fibrillar collagen organization. The variation of cartilage proteoglycan and collagen content with age was evaluated. Thickness measurements performed on both B-scan images and histologic sections were compared. Ultrasonic radiofrequency signals reflected by the cartilage surface and backscattered from its internal matrix were processed to estimate the integrated reflection coefficient (IRC) and apparent integrated backscatter (AIB). RESULTS: One-way ANOVA indicated that acoustic parameters and thickness change significantly (P < 0.05) as the animal matures because of age-related changes in cartilage composition and morphology. A moderate correlation was found between IRC and the animal age. The parameter decreased slightly but significantly over time. However, a good correlation was observed between the rat age and the AIB, which decreased significantly over time. The parameter variation was mostly related to the changes in collagen fiber orientation, and/or to a change in cell size, density and organization. CONCLUSIONS: Current results indicate that acoustic properties of cartilage are affected by maturation-related cartilage changes. This suggests that high frequency ultrasonography may serve as a useful means for the investigation of cartilage matrix structural changes occurring under various clinical circumstances, like those observed during osteoarthritis, and for the evaluation of the efficacy of specific therapeutics.

Aging↗
PubMed1984

Keratan sulfate content and articular cartilage maturation during postnatal rabbit growth.

This article describes the macromolecular changes in keratan sulfate and proteoglycan that occur in rabbit articular cartilage during postnatal development. Articular cartilage glycosaminoglycans from femoral condyles and the tibial plateaus of rabbits at 8, 12, 18, and 26 weeks and 2 years of age were extracted, fractionated, and quantified. The predominant glycosaminoglycan present in articular cartilage at 8 weeks was chondroitin sulfate. During subsequent maturation the relative proportions of keratan sulfate and chondroitin sulfate varied inversely. The greatest increase in the amount of keratan sulfate present in cartilage was observed between 12 and 26 weeks of age. Hyaluronic acid content was measurable at 12 weeks; afterward the amount remained relatively constant with age. Proteoglycans, extracted from 6-, 12-, and 22-week-old rabbit femoral and tibial cartilage in the presence of protease inhibitors, were analyzed on columns of Sepharose CL-2B. Cartilage proteoglycans decreased in hydrodynamic size between 12 and 22 weeks, corresponding to the period of maximal change in content of keratan and chondroitin sulfate.

Age Factors↗
PubMed1977

Membrane changes during cartilage maturation. Increase in 5'-nucleotidase and decrease in adenosine inhibition of adenylate cyclase.

To examine the potential participation of the plasma membrane in differentiation, we studied the enzymatic activities of 5'-nucleotidase and adenylate cyclase as a function of chondrocyte maturation. 16-day-old chick embryo tibiae epiphyses were dissected into proliferative, growing and hypertrophying zones. Partially purified membrane fractions prepared by differential centrifugation from the respective tissue segments were assayed for enzymatic activity. Cell suspensions from the same segments were examined cytochemically for the presence of 5'-nucleotidase. The findings show that the 5'-nucleotidase activity of the chick embryo epiphyseal cartilage has the following characteristics: (a) it has a Km of about 25 muM for 5'AMP, and is inhibited by a mixture of 2' and 3'AMP (apparent Ki about 10(-4) M) and by AOPCP; (b) it is predominantly localized at the cell surface but is also detected in the cytoplasm and in association with nuclear heterochromatin; and (c) it increases 10-fold (on a DNA basis) during the maturation of the epiphyseal cartilage cells. The adenylate cyclase activity has these characteristics: (a) it does not change during chondrocyte maturation (on a DNA basis); (b) its susceptibility to adenosine inhibition decreases at least 10-fold. The implication of these findings relative to a possible role of adenosine in cellular communication is discussed.

Adenosine↗
PubMed1990

Vitamin C regulation of cartilage maturation.

Treatment of chondrocytes with vitamin C under defined conditions in cell culture initiates a differentiation program that closely mimics the normal maturation of cells in the growth plate of long bones.

Animals↗
PubMed1995

Progression and recapitulation of the chondrocyte differentiation program: cartilage matrix protein is a marker for cartilage maturation.

During endochondral bone formation, chondrocytes in the cartilaginous anlage of long bones progress through a spatially and temporally regulated differentiation program before being replaced by bone. To understand this process, we have characterized the differentiation program and analyzed the relationship between chondrocytes and their extracellular environment in the regulation of the program. Our results indicate that, within an epiphyseal growth plate, the zone of proliferating chondrocytes is not contiguous with the zone of hypertrophic chondrocytes identified by the transcription of the type X collagen gene. We find that the postproliferative chondrocytes which make up the zone between the zones of proliferation and hypertrophy specifically transcribe the gene for cartilage matrix protein (CMP). This zone has been termed the zone of maturation. The identification of this unique population of chondrocytes demonstrates that the chondrocyte differentiation program consists of at least three stages. CMP translation products are present in the matrix surrounding the nonproliferative chondrocytes of both the zones of maturation and hypertrophy. Thus, CMP is a marker for postmitotic chondrocytes. As a result of the changes in gene expression during the differentiation program, chondrocytes in each zone reside in an extracellular matrix with a unique macromolecular composition. Chondrocytes in primary cell culture can proceed through the same differentiation program as they do in the cartilaginous rudiments. In culture, a wave of differentiation begins in the center of a colony and spreads to its periphery. The cessation of proliferation coincides with the appearance of CMP and eventually the cells undergo hypertrophy and synthesize type X collagen. These results reveal distinct switches at the proliferative-maturation transition and at the maturation-hypertrophy transition during chondrocyte differentiation and indicate that chondrocytes synthesize new matrix molecules and thus modify their preexisting microenvironment as differentiation progresses. However, when "terminally" differentiated hypertrophic chondrocytes are released from their surrounding environment and incubated in pellet culture, they stop type X collagen synthesis, resume proliferation, and reinitiate aggrecan synthesis. Eventually they cease proliferation and reinitiate CMP synthesis and finally type X collagen. Thus they are capable of recapitulating all three stages of the differentiation program in vitro. The data suggest a high degree of plasticity in the chondrocyte differentiation program and demonstrate that the progression and maintenance of this program is regulated, at least in part, by the extracellular environment which surrounds a differentiating chondrocyte during endochondral bone formation.

Aggrecans↗
PubMed1992

Type X collagen is transcriptionally activated and specifically localized during sternal cartilage maturation.

Type X collagen is an extracellular matrix protein which is synthesized by chondrocytes when they undergo hypertrophy. We present evidence here that the expression of type X collagen in the developing chick sternum is controlled primarily by transcriptional mechanisms. Using chondrocyte nuclei isolated from 15-, 16-, 17- and 18-day chick embryonic sterna, nuclear run-off assays demonstrate that type X collagen gene transcription begins at day 16 in chondrocytes isolated from the cephalic portion. This occurs two days prior to mineralization of this tissue as observed by alizarin red staining. The rate of type X transcription increases dramatically through days 17 and 18. Western blot analyses of extracts of freshly isolated sternal chondrocytes from the same stages show that intracellular levels of the type X protein follow the same time course. Immunostaining with a monoclonal antibody specific for type X collagen demonstrates that the initial appearances of hypertrophic cells and pericellular type X collagen occur at embryonic day 16 in the cephalic portion of sterna. Observation of immunostained cephalic sternal sections from day 18 embryos by confocal microscopy reveals that type X collagen is localized in a capsule-like configuration around each hypertrophic chondrocyte.

Animals↗
PubMed2001

SLC26A2 (diastrophic dysplasia sulfate transporter) is expressed in developing and mature cartilage but also in other tissues and cell types.

Mutated alleles of the SLC26A2 (diastrophic dysplasia sulfate transporter or DTDST) gene cause each of the four recessive chondrodysplasias, i.e., diastrophic dysplasia (DTD), multiple epiphyseal dysplasia (MED), atelosteogenesis Type II (AO2), and achondrogenesis Type IB (ACG1B). SLC26A2 acts as an Na(+)-independent sulfate/chloride antiporter and belongs to the SLC26 anion transporter gene family, currently consisting of six homologous human members. Although Northern analysis has indicated some expression in all tissues studied, the only tissue known to be affected by SLC26A2 mutations is cartilage. Abundant SLC26A2 expression has previously been detected in normal human colon by in situ hybridization. We have used in situ hybridization and immunohistochemistry to examine multiple normal tissues for the expression of human SLC26A2. As expected, a strong signal for SLC26A2 mRNA and protein immunostaining were detected in developing fetal hyaline cartilage, while bronchial cartilage showed mRNA expression in adult tissues. SLC26A2 expression could also be detected in eccrine sweat glands, in bronchial glands, and in placental villi. In addition, immunoreactivity for the SLC26A2 protein was observed in exocrine pancreas. Our results suggest a more limited expression pattern for SLC26A2 than that found by Northern analysis. However, SLC26A2 expression is also detected in tissues not affected in chondrodysplasias caused by SLC26A2 mutations.

Anion Transport Proteins↗
PubMed1975

Structural and histochemical aspects of the pericellular environment in cartilage.

Mature cartilage contains pericellular regions of matrix of fine texture, consisting of filamentous material and granules containing proteoglycan. Intercellular matrix contains collagen fibres with structural elements resembling those of the pericellular regions in the spaces between the fibres. Membrane bound bodies may be present at the margin of the pericellular region. Histochemically, chondroitin sulphate is found in the pericellular region in all zones but keratan sulphate is similarly stainable only in the deep zones of ageing cartilage.

Adult↗