Effects of adeno-associated virus (AAV) of transforming growth factors β1 and β3 (TGFβ1,3) on promoting synthesis of glycosaminoglycan and collagen type II of dedifferentiated nucleus pulposus (NP) cells
The effects of AAV-TGFbeta(1) and AAV-TGFbeta(3) on promoting synthesis of glycosaminoglycan and collagen type II of dedifferentiated rabbit lumbar disc NP cells were studied in this work. The rabbit lumbar disc NP cells were isolated and cultured. The earlier and later dedifferentiated NP cells were established by subculture. The AAV transfection efficiency to dedifferentiated NP cells was analyzed with AAV-EGFP in vitro. After dedifferentiated NP cells were transfected by AAV-TGFbeta(1) or AAV-TGFbeta(3), their biological effects on promoting synthesis of glycosaminoglycan or collagen type II were detected and compared by the methods of (35)S incorporation or immunoblotting. The experimental results showed that AAV could transfect efficiently the earlier dedifferentiated NP cells, but its transfection rate was shown to be at a low level to the later dedifferentiated NP cells. Both AAV-TGFbeta(1) and AAV-TGFbeta(3) could promote the earlier dedifferentiated NP cells to synthesize glycosaminoglycan and collagen type II, and the effect of AAV-TGFbeta(1) was better than that of AAV-TGFbeta(3). For the later dedifferentiated NP cells, the AAV-TGFbeta(3) could promote their synthesis, but AAV-TGFbeta(1) could slightly inhibit their synthesis. Therefore, AAV-TGFbeta(1) and AAV-TGFbeta(3) could be used for the earlier dedifferentiated NP cells, and the TGFbeta(3) could be used as the objective gene for the later dedifferentiated NP cells.
[Show abstract][Hide abstract] ABSTRACT: Extracellular matrix (ECM) remodeling is central to the development of restenosis after PTCA. Substantial evidence implicates transforming growth factor-beta1 (TGF-beta1), a regulator of ECM deposition by vascular cells, in its pathogenesis. TGF-beta3 reduces TGF-beta1-induced ECM deposition in cutaneous wounds. We therefore investigated the effects of intracoronary expression of TGF-beta3 and TGF-beta1 on luminal loss after angioplasty.
Porcine coronary arteries received an adenovirus expressing TGF-beta3, TGF-beta1, or lacZ (beta-galactosidase), or PBS only, at the site of angioplasty. Morphometric analysis 28 days after angioplasty confirmed reduced luminal loss in TGF-beta3 vessels (-0.65+/-0.10 mm2) compared with lacZ (-1.18+/-0.19 mm2) or PBS only (-1.19+/-0.17 mm2; P=0.003). Luminal loss was not reduced in TGF-beta1 vessels (-1.02+/-0.19 mm2; P=0.48). An increase in the external elastic lamina area in TGF-beta3-treated vessels (+0.73+/-0.32 mm2) contrasted with decreases in control vessels (mean, -0.53+/-0.17 mm2; P=0.001) and TGF-beta1 vessels (-0.87+/-0.34 mm2; P=0.003). Collagen content increased at the site of injury in TGF-beta3-treated vessels (26.1+/-14.2%) but decreased in the lacZ (-22.8+/-6.6%) and PBS-only (-23.4+/-7.0%; P=0.002) groups and was not significantly changed in TGF-beta1-treated vessels.
Expression of TGF-beta3 inhibits constrictive remodeling after PTCA and reduces luminal loss. This is accompanied by increased adventitial collagen, which may act as an external "scaffold" preventing vessel constriction. These findings confirm the potential of gene therapies that modify ECM remodeling for prophylaxis of restenosis.
[Show abstract][Hide abstract] ABSTRACT: The present study sought to elucidate the changes that occur in collagen chemistry in the early phases of disc degeneration.
To monitor the healing process of the injured anulus fibrosus and the secondary degenerative reactions in the nucleus pulposus.
Despite the importance of collagen chemistry under pathologic conditions in the intervertebral disc, knowledge of this aspect is very limited.
Fourteen pigs were stabbed with a scalpel blade in the anterior part of the anulus fibrosus of a lumbar disc. The animals were killed 2 weeks to 5 months after injury. The activities of prolyl 4-hydroxylase and galactosylhydroxylysyl glucosyltransferase, the total collagen content, and staining patterns for Types I, III, IV, and VI collagens were analyzed from different parts of the disc.
The most active phase of the healing process, assessed from the activities of enzymes involved in collagen biosynthesis, took place during the first month postoperatively. The anular lesion was found to cicatrize through formation of disorganized granulation tissue in which Type I, III, and, IV collagens were deposited. In the nucleus pulposus, activities of prolyl 4-hydroxylase and galactosylhydroxylysyl glucosyltransferase and total collagen content increased, and the originally rounded cells became more elongated, resembling fibroblasts.
The results of this study suggest that the altered composition of collagens observed in the degenerate porcine nucleus pulposus results from changes in cell phenotype: Notochondral cells were replaced by fibroblast-like cells. It is likely that trauma to the anulus fibrosus can initiate a progressive degenerative process in the disc tissue.
[Show abstract][Hide abstract] ABSTRACT: Very little is known about the turnover of extracellular matrix in the human intervertebral disc. We measured concentrations of specific molecules reflecting matrix synthesis and degradation in predetermined regions of 121 human lumbar intervertebral discs and correlated them with ageing and Thompson grade of degeneration. Synthesis in intervertebral discs, measured by immunoassay of the content of a putative aggrecan biosynthesis marker (846) and the content of types I and II procollagen markers, is highest in the neonatal and 2-5-yr age groups. The contents of these epitopes/molecules progressively diminished with increasing age. However, in the oldest age group (60-80 yr) and in highly degenerated discs, the type I procollagen epitope level increased significantly. The percentage of denatured type II collagen, assessed by the presence of an epitope that is exposed with cleavage of type II collagen, increased twofold from the neonatal discs to the young 2-5-yr age group. Thereafter, the percentage progressively decreased with increasing age; however, it increased significantly in the oldest group and in highly degenerate discs. We identified three matrix turnover phases. Phase I (growth) is characterized by active synthesis of matrix molecules and active denaturation of type II collagen. Phase II (maturation and ageing) is distinguished by a progressive drop in synthetic activity and a progressive reduction in denaturation of type 11 collagen. Phase III (degeneration and fibrotic) is illustrated by evidence for a lack of increased synthesis of aggrecan and type II procollagen, but also by an increase in collagen type II denaturation and type I procollagen synthesis, both dependent on age and grade of tissue degeneration.
Note: Although carefully collected, accuracy of this list of references cannot be guaranteed.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.