Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Granulation Tissue”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
PubMed1987

Tumor necrosis factor stimulates gelatinase and collagenase production by granulation tissue in culture.

Tumor necrosis factor (TNF, 2.6 X 10(-11)-10(-9) M) caused an increase in the production of active gelatinase and latent collagenase by granulation tissue in culture. As determined by SDS-substrate polyacrylamide gel electrophoresis, granulation tissue produced mainly two species of gelatinase with molecular weights of 64 kDa and 57 kDa, and an additional 80-kDa gelatinase was produced by TNF treatment. The results suggest that TNF may play a role in a rapid collagen turnover in the carrageenin-induced granulation tissue in rats.

Animals↗
PubMed1999

360 Degrees of epibulbar granulation tissue thirteen years after silicone circle buckle operation.

To demonstrate a granulomatous reaction to silicone buckel thirteen years after retinal detachment surgery. We report on a 71-year-old man who developed a 360 degrees of epibulbar granulation tissue due to silicone circle buckel. The granulation tissue was demonstrated by a computer tomography and histologically. A granulomatous reaction to silicone circle buckel can be found many years from the first operation. Biopsy is always necessary to establish a definitive diagnosis. Treatment of 360 degrees of epibulbar granulation tissue causing ocular dysfunction is by surgical excision.

Aged↗
PubMed1994

Reduction of collagen degradation in experimental granulation tissue by vitamin E and selenium.

The importance of antioxidants in inflammatory tissues has been studied in vivo. Degradation of homologous 3H-collagen powder by experimental granulation tissue induced by cellulose sponges in the rat was monitored as the radioactivity excreted in urine. By administering pharmacological doses of both vitamin E and selenium subcutaneously and by injection into sponges implanted subcutaneously, this breakdown of collagen was reduced. Injections in the sponges also arrested the maturation of the granulation tissue. Vitamin E and selenium are potential inhibitors of the free oxygen radicals from phagocytic inflammatory cells. It is therefore suggested that these radicals may play a rôle in the collagen destruction by granulation tissues, as in periodontitis.

Animals↗
PubMed2005

Redistributions of macrophages expressing the macrophage galactose-type C-type lectin (MGL) during antigen-induced chronic granulation tissue formation.

Cell surface lectins are known to regulate trafficking of cells in the immune system, yet the role of macrophage galactose-type C-type lectin 1 and 2 (MGL1/2) is poorly understood. In this study, antigen-specific chronic inflammation was induced in a subcutaneous air pouch model in mice, and distribution of cells expressing MGL1/2 was investigated. Azobenzenearsonate-conjugated acetylated BSA, used as an antigen, was introduced into an air pouch of immunized mice, and tissue formation and distribution of MGL1/2-positive cells in the sub-dermal regions was examined. Thickness of the inflammatory tissue and number of MGL1/2-positive cells simultaneously reached the maximum at day 4 and returned to the control level at day 6 or 8. When additional antigenic challenges were given, a chronic granulation tissue, which had two distinct layers, was generated. In the chronic tissue, CD11b-positive/MGL1/2-negative cells were abundant in the area close to the antigenic stimulus, while the area far from the antigenic stimulus was dominated by MGL1/2-positive/CD11b-negative or -low cells. Flow cytometric analyses of isolated cells from the granulation tissue revealed that MGL1/2-positive cells expressed MHC class II at high levels, CD11b at low levels but no CD11c. MGL1/2-positive and -negative fractions were separated from cells in the granulation tissue and a higher level of IL-1alpha messenger RNA than negative populations was detected in the MGL1/2-positive fraction by the semi-quantitative reverse transcription-PCR method. IL-1alpha production by MGL1/2-positive cells was also immunohistochemically detected. Results suggest that MGL1/2-positive cells represent a distinct sub-population of macrophages, having unique functions in the generation and maintenance of granulation tissue induced by antigenic stimuli.

Animals↗
PubMed1983

Type V collagen during granulation tissue development.

The collagen content, as determined by hydroxyproline assay, of experimental granulation tissue in rats was observed to increase rapidly 21 days, and less rapidly to 90 days of tissue development. Resistance of the collagen to pepsin digestion reached a maximum at 21 days, suggesting more extensive or more stable crosslinking at that time. Type V collagen and the expected collagen types I and III were present in pepsin extracts of the granulation tissue as determined by SDS-polyacrylamide gel electrophoresis. Over 3 months of tissue development the relative quantity of type V collagen, as evidenced by changes in the alpha B chain, varied in parallel with the changing vascularity of the tissue, suggesting an association with capillary endothelial cells and angiogenesis.

Animals↗
PubMed1997

Tumour necrosis factor-alpha selectivity modulates expression of collagen genes in rat granulation tissue.

OBJECTIVE: To study the effects of tumour necrosis factor-alpha (TNF-alpha) on granulation tissue in rats. DESIGN: Animal experiment. SETTING: University Hospital, Finland. MATERIAL: 48 rats in 6 groups. INTERVENTIONS: The test implants were treated with either a single or daily injections of 200 ng of TNF-alpha. The samples were collected 4 and/or 7 days postoperatively. MAIN OUTCOME MEASURES: Pro alpha 1 (I) and pro alpha 1 (III) collagen mRNA concentrations, hydroxyproline, nitrogen, uronic acids, and hexosamine content of the sponge; and ingrowth of new granulation tissue into the sponge. RESULTS: A single application of TNF-alpha resulted in no significant differences between the groups. After daily applications of TNF-alpha the accumulation of collagen hydroxyproline and volume of ingrowth of granulation tissue were significantly lower than in the controls. After 7 days there were significant reductions in the concentrations of RNA-ribose, nitrogen, and uronic acids. Daily injections of TNF-alpha reduced pro alpha 1 (I) collagen mRNA concentrations but those of pro alpha 1 (III) collagen mRNA levels were not lowered to the same extent. CONCLUSION: Repeated application of TNF-alpha was required to reduce the synthesis of collagen. This down-regulation was selective as pro alpha 1 (I) collagen mRNA concentrations were lowered more than those of pro alpha 1 (III) collagen mRNA.

Animals↗
PubMed1981

Influence of zinc on synthesis and the accumulation of collagen in early granulation tissue.

Chronic zinc deficiency causes a delay of reparative processes. The rate of repair is normalized by the administration of zinc. An acute lowering of the serum zinc level follows trauma. In a previous experimental study, it was demonstrated that the intramuscular administration of zinc beginning before trauma results in an increased collagen accumulation in early granulation tissue. In this study, the rate of collagen synthesis was determined to see if the higher amount of collagen found in early granulation tissue could be explained by increased collagen synthesis. The rate of collagen synthesis was studied by the determination of the incorporation of 14C-L-proline into collagen in vivo and in vitro. No difference was found regarding collagen synthesis in the granulation tissue of rats in the control and zinc treated groups. Specific activity of collagen, a measure of newly synthesized collagen in relation to the total amount of collagen, was found to increase markedly during the observation time. Further, the specific activity was found to be lower in the rats of the zinc treated groups than in the rats of the control groups on days 4 and 5, an indication that, after the administration of zinc there is more earlier synthesized, not labeled, collagen present. A possible explanation is that there is a concomitant synthesis and breakdown of collagen in granulation tissue and that the rate of breakdown is decreased by the administration of zinc.

Animals↗
PubMed1987

Epidermal growth factor increases collagen production in granulation tissue by stimulation of fibroblast proliferation and not by activation of procollagen genes.

The effects of epidermal growth factor (EGF) on granulation-tissue formation and collagen-gene expression were studied in experimental sponge-induced granulomas in rats. After daily administration of 5 micrograms of EGF into the sponge, total RNA was extracted from the ingrown granulation tissue at days 4 and 7 and analysed by Northern hybridization for the contents of mRNAs for types I and III procollagens. EGF treatment increased procollagen mRNA, particularly at day 4. To determine whether this elevation was due to increased proliferation of collagen-producing fibroblasts or to activation of collagen-gene expression in these cells, fibroblast cultures were started from granulation tissue and treated with EGF. These experiments confirmed that EGF is a potent mitogen for granuloma fibroblasts in a dose-dependent manner. The effect of EGF treatment on radioactive hydroxyproline production in cultured cells was inhibitory. The decreased rate of collagen synthesis was also indicated by decreased amounts of procollagen mRNAs. The results suggest that the stimulation of wound healing and collagen production by EGF is due to increased fibroblast proliferation, and not to increased expression of type I and III procollagen genes.

Animals↗
PubMed1977

Granulation tissue in the umbilical cord.

The development of granulation tissue in the umbilical cord is described here for the first time. Nothing is known about the conditions necessary to produce such tissue.

Adolescent↗
PubMed1993

Increased gene expression of scatter factor-hepatocyte growth factor and basic fibroblast growth factor in granulation tissue in the rat.

Scatter factor-hepatocyte growth factor is a protein secreted by fibroblasts which disperses colonies of epithelial cells and keratinocytes in culture. The factor is also a patent mitogen for hepatocytes, synthesized in the liver. Basic fibroblast growth factor, another heparin-binding factor, is most abundant in the brain but also plays a role in wound healing. Using a solution hybridization/RNAase protection assay, we have measured the abundance of messenger RNA for scatter factor-hepatocyte growth factor and basic fibroblast growth factor in granulation tissue obtained from subcutaneously Hunt-Schilling wound cylinders. The levels of scatter factor-hepatocyte growth factor messenger RNA increased after weeks 2 through 4 to a twofold higher level in weeks 5 through 7 after implantation of the cylinders, whereas no changes in basic fibroblast growth factor messenger RNA levels were noticed. At week 3 after implantation of the cylinders, scatter factor-hepatocyte growth factor messenger RNA levels in granulation tissue were more than threefold higher than in skin dermis fibroblasts but markedly lower than in the liver. The abundance of basic fibroblast growth factor messenger RNA was also significantly increased in granulation tissue compared with dermis but, as expected, markedly lower than in the brain. In conclusion, the gene expression of the scatter factor-hepatocyte growth factor, as well as basic fibroblast growth factor, is increased in granulation tissue. Because there was a time-dependent increase in the expression of scatter factor-hepatocyte growth factor, it is hypothesized that scatter factor-hepatocyte growth factor acts as a signal from fully developed granulation tissue to stimulate skin epithelial cells to scatter over the wound.

Journal Article↗
PubMedDate not supplied

Repeated additions of hyaluronan alters granulation tissue deposition in sponge implants in mice.

The role for the metabolism of hyaluronic acid in the repair process is uncertain. Fetal dermal wounds do not heal by scarring and have sustained high levels of hyaluronic acid. In contrast, adult dermis is repaired by scarring and has less hyaluronic acid. Initially after injury, hyaluronic acid is elevated in both adult and fetal wounds, and although it remains elevated in fetal repair, it is rapidly degraded in adult wounds. The chronic addition of hyaluronic acid or hyaluronidase to polyvinyl alcohol sponge implants in adult mice was investigated in this study. Polyvinyl alcohol sponge implants containing a central reservoir were placed subcutaneously in the dorsum of adult male CD-1 mice. Mice were divided into three groups: a phosphate-buffered saline control, a 20 microgram hyaluronic acid treatment group, and a 10 U hyaluronidase treatment group. The central reservoir of each sponge implant received appropriate compound every 3 days for 2 weeks via transdermal injection and were then evaluated histologically. At 2 weeks, the cellular density and the quantity of granulation tissue deposition were the greatest in the hyaluronidase group and were lowest in the hyaluronic acid group. In addition, the organization of collagen fiber bundles was the most dense in the hyaluronidase group and least in the hyaluronic acid group. In a second experiment, polyvinyl alcohol sponge implants in mice received either phosphate-buffered saline solution or 20 microgram hyaluronic acid every 3 days for 1 week. On day 5, an aliquot of fluorescently tagged native collagen was injected into the sponges. Sponges were harvested at day 7, cryosections made, and the presence of autofluorescent collagen fibers assessed. The autofluorescent collagen fiber bundles in the phosphate-buffered saline solution group were organized in thick parallel bundles, whereas the collagen bundles from hyaluronic acid-treated implants were organized in fine lacelike structures. Chronic addition of hyaluronic acid appears to mimic the fetal dermal connective tissue matrix in which repair proceeds with diminished collagen deposition, organized in finer collagen fiber bundles in granulation tissue. On the other hand, the removal of hyaluronic acid by the chronic administration of hyaluronidase increases the amount of granulation tissue. Elevated levels of hyaluronic acid in granulation tissue appear to modulate the ability of resident fibroblasts to organize collagen fiber bundles.

Adjuvants, Immunologic↗
PubMed2002

Effects of interleukin-8 on granulation tissue maturation.

The inflammatory alpha-chemokine, interleukin-8 (IL-8), affects the function and recruitment of various inflammatory cells, fibroblasts, and keratinocytes. Gap junctions are anatomical channels that facilitate the direct passage of small molecules between cells. The hypothesis is that IL-8 enhances gap junctional intercellular communication (GJIC) between fibroblasts in granulation tissue, which increases the rate of granulation tissue maturation. In vitro, human dermal fibroblasts were incubated with IL-8 prior to scrape loading, a technique that quantifies GJIC. Polyvinyl alcohol (PVA) sponges were implanted within subcutaneous pockets in rats and received local injections of either IL-8 or saline and were harvested on day 11. In vitro, IL-8 treated fibroblasts demonstrated an increase in GJIC by scrape loading compared to saline treated controls. In vivo, IL-8 treated PVA sponges demonstrated a decrease in cell density and an increase in vascularization compared to saline controls by H&E staining. Polarized light viewed Sirius red-stained specimens demonstrated greater collagen birefringence intensity, indicating thicker, more-mature collagen fibers. IL-8 increases GJIC in cultured fibroblasts and induces a more rapid maturation of granulation tissue.

Animals↗
PubMed1984

[Granulation tissue: inflammation and regeneration].

Healing of the external defects by the primary tension, under the scab, or by the secondary tension through the suppuration as well as the formation of granulation tissue (GT) in other organs, represent an adequate homeostatic response to the injury with stereotype kinetics of the inflammation and regeneration. The altered general and local responsiveness trophic disorders, burn and radiation trauma result in collapse of the autoregulatory mechanisms, pronounced disturbance of phagocytosis, microcirculation, mediator and contact cell interaction. This provokes the inhibition of fibroblast proliferation, depression and perversion of fibrillogenesis and the granulation tissue maturation, the formation of abnormal granulation tissue with repeated wakes of sclerosis, necrosis and inflammation, formation of persisting wounds, ulcers, hypergranulations or chronic inflammatory processes. Homeostatic protective response transforms into the pathologic response due to dissociation between the inflammation and regeneration and formation of "vicious circle".

Granulation Tissue↗
PubMed1987

Selective inhibition of collagen accumulation by N-(3,4-dimethoxycinnamoyl)anthranilic acid (N-5') in granulation tissue.

The effect of topically applied N-5', an inhibitor of chemical mediator release from mast cells, on the carrageenin-air-pouch inflammation was studied. The formation of granulation tissue, the accumulation of exudate and the number of infiltrating cells were significantly reduced by the treatment with N-5' (100 mg/kg). The collagen content in granulation tissue was dose-dependently reduced without affecting the noncollagen protein and DNA content by treatment with N-5'. At a dose of 100 mg/kg of N-5', prolyl hydroxylase activity in the tissue was significantly decreased. The selective inhibition of collagen accumulation in granulation tissue resulted from reduction of collagen biosynthesis in vivo. N-5' did not directly inhibit collagen synthesis by diploid fibroblasts, but inhibited fibroblast proliferation in culture. Such results indicate that one of the inhibitory mechanisms of collagen accumulation by N-5' in inflamed sites may involve the inhibition of fibroblast proliferation.

Animals↗
PubMed2005

Regulation of alpha-smooth muscle actin expression in granulation tissue myofibroblasts is dependent on the intronic CArG element and the transforming growth factor-beta1 control element.

Myofibroblasts are specialized contractile fibroblasts that are critical in wound closure and tissue contracture. Generation of contractile force is correlated with the expression of alpha-smooth muscle actin (alpha-SMA); however, little is known regarding molecular mechanisms that control activation of alpha-SMA in myofibroblasts in granulation tissue. The aims of the present studies were to identify sufficient promoter regions required for alpha-SMA expression in myofibroblasts in vivo and to determine whether activation of alpha-SMA expression in myofibroblasts in vivo is dependent on an intronic CArG [CC(A/T)6GG] and a transforming growth factor-beta1 control element (TCE) that are required for alpha-SMA expression in smooth muscle cells. A Lac Z transgene construct from -2600 through the first intron was expressed in myofibroblasts within granulation tissue of cutaneous wounds in a pattern that closely mimicked endogenous alpha-SMA expression. Mutation of either the intronic CArG element or the TCE completely inhibited transgene expression in myofibroblasts in granulation tissue and responsiveness to transforming growth factor-beta1 in cultured transgenic fibroblasts. These same elements were also critical in regulating alpha-SMA expression during skeletal muscle repair but not during skeletal muscle development. Taken together, these results provide the first in vivo evidence for the importance of the intronic CArG and TCE cis-elements in the regulation of alpha-SMA expression in myofibroblasts in granulation tissue.

Actins↗
PubMed1998

Enhanced expression of transforming growth factor-beta type I and type II receptors in wound granulation tissue and hypertrophic scar.

In the present study we have analyzed and compared, by immunohistochemistry and in situ hybridization, the expression pattern of the R4/ALK5 transforming growth factor (TGF)-beta type I receptor (RI) and the TGF-beta type II receptor (RII) in normal human skin, in wounded skin at various stages during the transition of wound granulation tissue to scar, and in long-persisting post-burn hypertrophic scars. In normal human skin, expression of RI and RII was clearly visible in the epidermis, in epidermal appendages, and in vascular cells, although only a small number of dermal fibroblasts revealed detectable levels of TGF-beta receptor expression. In contrast, granulation tissue fibroblasts showed strong expression of both TGF-beta receptor types, although in normal-healing excisional wounds their density decreased during granulation tissue remodeling. However, in post-burn hypertrophic scars, RI- and RII-overexpressing fibroblasts were found in high densities up to 20 months after injury. From these findings we suggest that the repair process of deep wounds involves the transformation of a subset of fibroblastic cells toward an increased TGF-beta responsiveness and a transient accumulation of these cells at the wound site. In addition, our study provides evidence that excessive scarring is associated with a failure to eliminate TGF-beta receptor-overexpressing fibroblasts during granulation tissue remodeling, which leads to a persistent autocrine, positive feedback loop that results in over-production of matrix proteins and subsequent fibrosis.

Actins↗
PubMed2002

Diffusion-weighted imaging for differentiating recurrent cholesteatoma from granulation tissue after mastoidectomy: case report.

Identification of recurrent cholesteatoma and differentiation from postoperative granulation tissue is important in a patient who has undergone mastoidectomy for cholesteatoma. We describe the diffusion-weighted imaging findings and apparent diffusion coefficient values in a case of recurrent cholesteatoma. This case suggests possible differentiation of cholesteatoma from granulation tissue on the basis of diffusion-weighted imaging findings.

Cholesteatoma, Middle Ear↗
PubMed1999

Release of mechanical tension triggers apoptosis of human fibroblasts in a model of regressing granulation tissue.

In an in vitro model of granulation tissue, early passage human diploid fibroblasts under mechanical tension showed little or no apoptosis. Release of mechanical tension triggered an apoptotic response that occurred within 3-6 h and reached a plateau by 24 h. The percentage of apoptotic cells (approximately 15%) remained constant up to 7 days, and after 3 days, total cell number declined. Identification of mechanical unloading as a stimulus for apoptosis, without application of pharmacologic or genetic intervention, is a novel observation that permits us to model similar events that occur during wound healing. Studies on the mechanism regulating apoptosis under these conditions established that the apoptotic response does not require differentiation of cells into myofibroblasts but is governed by a combination of mechanical tension and growth factors in the collagen matrix.

Actins↗