Differential upregulation of the three transforming growth factor beta isoforms in human osteoarthritic cartilage.

OBJECTIVES: Decreased levels of transforming growth factor beta (TGFbeta) have been related to the failure of cartilage repair in experimental models of osteoarthritis. This study aimed to examine this aspect of osteoarthritis in human cartilage. METHODS: Cartilage samples were obtained from 11 patients with hip osteoarthritis and 11 patients with femoral neck fracture who were undergoing total hip replacement. Gene expression of the three TGFbeta isoforms, collagen type II (COL2A1) and aggrecan (AGC1) was analysed by reverse transcription quantitative PCR and immunohistochemistry. RESULTS: Expression of the three TGFbeta isoforms was increased in osteoarthritis cartilage. The upregulation was more marked for the TGFbeta3 isoform (2.3-fold) than for TGFbeta1 (1.6-fold) or TGFbeta2 (1.7-fold). The messenger RNA levels of TGFbeta1 and TGFbeta2 were strongly correlated in osteoarthritis cartilage (r(s) = 0.83, p = 0.002), but levels of TGFbeta3 were uncorrelated with any of the two other TGFbeta isoforms. Immunohistochemistry showed an extension of immunoreactivity for the three TGFbeta isoforms to more chondrocytes and to deeper cartilage layers in the more severe osteoarthritis lesions. No correlation of TGFbeta isoforms with COL2A1 or AGC1 expression levels was found. CONCLUSIONS: The three isoforms of TGFbeta were differentially upregulated in late osteoarthritis in relation to an increased percentage of TGFbeta-positive chondrocytes. These results indicate that cartilage damage progresses in spite of the TGFbeta stimulus for cartilage anabolism and that other causes of the failure to cope with the increased cartilage catabolism of osteoarthritis should be investigated.

Morphological study of root surfaces in teeth with adult periodontitis.

BACKGROUND: Our study correlates the histological alterations in the cementum (especially resorption areas) of teeth with the different stages of adult periodontitis. METHODS: Sixty-seven teeth affected by adult periodontitis and 7 healthy teeth extracted from patients over 40 years old were used. The teeth were divided into 3 groups according to radiographic data: group 1: five teeth with bone loss less than one-third of the normal alveolar height; group 2: thirty-one teeth with bone loss between one and two thirds; and group 3: thirty-one teeth with bone loss greater than two thirds. The samples were prepared for light and scanning electron microscopy, considering the gingival, middle, and apical thirds in each root. RESULTS: Two control teeth, 4 teeth in group 1, and all teeth in groups 2 and 3 showed resorption areas. Regarding the gingival third, the control teeth did not show any resorption, while 25% of affected teeth in group 1, 38.7% of teeth in group 2, and 35.5% of teeth in group 3 exhibited resorption. Regarding the middle third, 50% of affected teeth belonging to the control group and group 1; 67.7% of teeth in group 2; and 87.1% of teeth in group 3 showed resorption. Regarding the apical third, all teeth belonging to the control group and group 1 showed resorption, while 93.5% and 87.1% of teeth in groups 2 and 3, respectively, exhibited resorption. Most of the resorptions did not extend beyond the cementum. However, in 29.0% of teeth in group 2 and 38.7% of teeth in group 3, resorption had spread as far as the dentin. All the lesions in the control group and group 1 were practically repaired, while only 71.0% of teeth in group 2 and 61.3% of teeth in group 3 showed some sign of reparation. However, in groups 2 and 3, practically all lesions affecting dentin were repaired. CONCLUSIONS: These data suggest that the spread of root resorption is associated with inflammation. This study also suggests that the capacity for repair of root resorption is diminished with greater severity of periodontitis.

Variation in articular cartilage in rabbits between weeks six and eight.

BACKGROUND: Previous studies of variation in cartilage characteristics with age have involved comparison of young and adult individuals, but no data on short-term age-related change are available. Such data are important for studies of the response of cartilage to experimental stimuli in young rabbits, to distinguish the response to the stimuli from accompanying age-related changes. METHODS: We used light microscopy to study the thickness, cell density, and degree of histological definition of articular cartilage on the femoral trochlea of 6-, 7-, and 8-week-old rabbits. RESULTS: Thickness and cell density both decline significantly with age. The decline in cell density is more marked in surface layers of cartilage and is accompanied by an increase in the safranin O-staining affinity of the extracellular matrix and an extension of this affinity towards the surface. CONCLUSIONS: Our results indicate that the synthesis of matrix components becomes more important relative to proliferative activity. The traditionally defined histological layers (zones I, II, III, and IV) are not clearly distinguishable in rabbits of this age. In 6- and 7-week old animals only a "surface" (I/II) and a "deep" layer (III) can be distinguished. By 8 weeks, zones I and II are well defined but the mineralization front (marking the boundary between zones III and IV) is still absent.