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At least 487 records · Page 27Linked to original sources
PubMed2001

Regulation of angiogenesis and matrix remodeling by localized, matrix-mediated antisense gene delivery.

Implantation of biomaterials, such as glucose sensors, leads to the formation of a poorly vascularized collagenous capsule that can lead to implant failure. This process, known as the foreign body reaction (FBR), develops in response to almost all biomaterials and consists of overlapping phases similar to those in wound healing. Implantation of porous biomaterials, such as polyvinyl alcohol sponges, also leads to granuloma formation within the interstices of the sponge prior to encapsulation by the FBR. We asked whether delivery of an antisense cDNA for the potent angiogenesis inhibitor thrombospondin (TSP) 2 would enhance blood vessel formation and alter collagen fibrillogenesis in the sponge granuloma and capsule. Collagen solutions were mixed with plasmid to generate gene-activated matrices (GAMs) and applied to biomaterials that were then implanted subcutaneously. Sustained expression of plasmid-encoded proteins was observed at 2 weeks and a month following implantation. In vivo delivery of plasmids, encoding either sense or antisense TSP2 cDNA, altered blood vessel formation and collagen deposition in TSP2-null and wild-type mice, respectively. Untreated implants, implanted next to GAM-treated implants, did not show exogenous gene expression and did not elicit altered responses, suggesting that gene delivery was limited to implant sites. This method of antisense DNA delivery has the potential to improve the performance and life span of implantable delivery devices and biosensors.

Animals↗
PubMed1989

Growth rate of human fibroblasts is repressed by the culture within reconstituted collagen matrix but not by the culture on the matrix.

Effect of reconstituted type I collagen gel on in vitro growth of fibroblasts was examined. A prolonged lag period was observed by culture either on the surface of three-dimensional collagen gel ("on-gel") or within the gels ("in-gel") as compared with the culture on plastic dishes. The rate of cell proliferation in logarithmic phase growth was repressed by the culture "in-gel" but not by the culture "on-gel". The differential growth rates between "in-gel" culture and "on-gel" culture should be ascribed to difference in distributions of interacting sites between cell and collagen fibrils. The repression of cell growth was more marked in a contracting collagen gel which contains higher density of collagen fibrils. The cell density in contracted gel per unit cross-section area was found to be much lower than that of confluent monolayer culture. These results suggest that the repression of cell growth by collagen fibrils in the three-dimensional gels is not due to direct cell-cell contact, but due to the distribution and number of contact sites between a cell and collagen fibrils.

Cell Count↗
PubMed2003

Differences in estrogen modulation of tissue inhibitor of matrix metalloproteinase-1 and matrix metalloproteinase-1 expression in cultured fibroblasts from continent and incontinent women.

OBJECTIVE: The purpose of this study was to investigate the effect of increasing estrogen concentrations on metalloproteinase and tissue inhibitors of metalloproteinase protein expressions in cultured pelvic fibroblasts that were obtained from continent and incontinent women. STUDY DESIGN: Periurethral vaginal wall tissues were taken from four stress incontinent and three continent premenopausal women who underwent gynecologic surgery for benign indications. Protein was extracted from these tissues, and Western blot analysis was performed to document that fibroblasts from continent and incontinent women differed with respect to metalloproteinase and tissue inhibitors of metalloproteinase production. One age-matched tissue pair was prepared for fibroblast culture. Cells were cultured with increasing concentrations of estradiol (0-500 pg/mL). Extracellular metalloproteinase and tissue inhibitors of metalloproteinase were assessed semiquantitatively with Western blotting. RESULTS: Periurethral vaginal tissues from incontinent women expressed less tissue inhibitors of metalloproteinase when compared with tissue from the control subjects; there was no difference in the expression of cleaved, active metalloproteinase protein. Tissue inhibitors of metalloproteinase expression from fibroblasts of continent women significantly increased with increasing estradiol concentrations (0-100 pg/mL, P <.05). No significant dose response was seen in fibroblasts from an incontinent woman. Metalloproteinase expression was not altered by increasing estradiol concentrations in fibroblasts from either continent or incontinent women. CONCLUSION: This preliminary in vitro study suggested that, in fibroblasts that were derived from the continent woman, tissue inhibitors of metalloproteinase protein production increases with increasing estrogen levels and that, in stress incontinent fibroblasts, no similar increase occurs. Neither group demonstrated a change in metalloproteinase production in response to varying estrogen levels, which suggests that estrogen may inhibit collagen degradation in continent women by increasing tissue inhibitors of metalloproteinase production but exerts a reduced inhibitory effect on collagenolysis in women with stress urinary incontinence.

Adult↗
PubMed2001

Characterization of matrix metalloprotease activities induced in the sea urchin extraembryonic matrix, the hyaline layer.

Hyaline layers, freshly prepared from one-hour-old embryos, were devoid of gelatin-cleavage activity. However, upon storage at 4 degrees C, gelatin-cleavage activities appeared; three species of apparent mol mass 94 --> 117-, 90-, and 45-kDa were seen. All three species required zinc for activity. Using gel-exclusion chromatography we separated the 94 --> 117-, and 90-kDa species from the 45-kDa activity. The two higher mol mass species were inhibited by ethylenebis (oxyethylenenitrilo) tetraacetic acid and the lost activity was restored by calcium. Reconstitution of activity occurred with an apparent dissociation constant (calcium) of 5 microM. The presence of millimolar concentrations of magnesium had a minimal inhibitory effect on activity. The thermal denaturation profile of the higher mol mass gelatin-cleavage activity was significantly different in the presence and absence of calcium. Stabilization of these activities against thermal denaturation at 60 degrees C occurred with an apparent dissociation constant (calcium) of 0.6 mM. Magnesium had no significant effect on the thermal denaturation profile. Collectively, these results suggest at least two different modes of interaction between calcium and the higher mol mass gelatinases. These conclusions are discussed in the context of the high calcium and magnesium concentrations present in the sea water environment of the sea urchin embryo.

Animals↗