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PubMed2004

Basic fibroblast growth factor promotes apoptosis and suppresses granulation tissue formation in acute incisional wounds.

Cytokines are thought to play an important role in cellular loss and apoptosis during the repair of granulation tissue. In order to investigate the role of apoptosis following the administration of basic fibroblast growth factor (bFGF) to a wound, the present study examined the relationship between the degree of granulation tissue formation and the level of apoptosis in rat skin incisional wounds, following treatment with an intradermal injection of bFGF (0.1 microg and 1 microg per cm of wound). Histological assessment of the width of the wound tissue showed that the degree of granulation tissue in the 1 microg-bFGF-treated group had increased by day 7, but then subsequently diminished by days 14 and 28. The TUNEL index increased rapidly from day 1, peaking on day 7, with the index being higher in the 1 microg-bFGF-treated group on days 4, 7, and 14, when compared with a control group. In parallel with a marked increase in the TUNEL index over the first 14 days, the number of cells positive for vimentin and CD3 in the 1 microg-bFGF-treated wounds had decreased by day 14. The number of PCNA-positive cells, an indicator of cell proliferation, peaked on day 4 in the bFGF-treated wounds and then declined rapidly. On the basis of these results, it is suggested that the suppression of granulation tissue formation in bFGF-treated wounds is mainly due to an early and persistent increase in apoptosis in the granulation tissue cells. The expression of both transforming growth factor (TGF)-beta1 and bFGF was also elevated in the bFGF-treated wounds on days 4 and 7, suggesting that fibroblast apoptosis was induced by bFGF treatment. Unexpectedly, on day 28, the wound breaking strength was not reduced in the bFGF-treated wounds. These results indicate that apoptosis regulation following bFGF administration to an incisional wound may lead effectively to granulation tissue formation and promote a scar-less repair process.

Acute Disease↗
PubMed1975

Granulation tissue formation in viscose cellulose sponges of different design.

Granulation tissue formation was studied in subcutaneously implanted viscose cellulose sponges of different design using histological and chemical methods. Two different models of sponges were used, one of cubical shape and another rectangular and thin. The sponges had the same weight. After one week of implantation, histological examination of the cubical sponges showed granulation tissue only in the periphery and a central cavity filled with inflammatory cells. The histological texture of the thin sponges showed that they were almost completely filled with granulation tissue with a minimal central cavity and very few inflammatory cells. DNA values of the cubical sponges were about 20% higher than those of the thin sponges. After aspiration of the exudate in the cubical sponges, the DNA values were about the same as those in the thin sponges. The amount of hydroxyproline and RNA were about the same regardless of whether the sponges were cubic or thin or the exudate of the cubic sponges had been aspirated or not. At two weeks there was still a central cavity in the cubic sponges but very few inflammatory cells. DNA values at this time of observation were also the same in both models of sponges. Thus the thin-shaped model of sponge seems to be preferable to the cubic one when the time of observation is shorter than two weeks.

Animals↗
PubMed1980

Sequential appearance of fibronectin and collagen in experimental granulation tissue.

The sequential appearance of fibronectin and collagenous proteins was studied by immunofluorescence in experimental granulation tissue in the mouse. Granulation tissue was induced by subcutaneous implantation of viscous cellulose sponges into the neck. When sponges were invaded by granulation tissue, fibronectin appeared early together with the invading fibroblasts. Interstitial collagens, type III and type I, appeared 2 to 7 days later. When the collagen had matured into bundles, fibronectin diminished or disappeared. The results suggest that fibronectin functions as a primary matrix for organization of the collagenous connective tissue during the tissue repair process.

Animals↗
PubMed1978

Alkaline ribonuclease associated with polyribosomes in fibroblasts of experimental granulation tissue.

Alkaline ribonuclease (RNase) from polyribosomes derived from experimental granulation tissue has been purified 1900-fold through affinity chromatography. The preparation was homogeneous in sodium dodecyl sulfate (SDS) polyacrylamide-gel electrophoresis with an estimated molecular weight of 15 000. Purified RNase was completely inhibited in the presence of divalent ions Mg2+(100 mM) and Ca2+(100 mM) but activated slightly with Na+(50 mM). The enzyme is an endonuclease and the best substrates were poly(U), mixed RNA from yeast, rRNA from granulation tissue and poly(C). The estimated apparent Km-values were 0.037, 0.064, 0.13 and 0.27 g1-1, respectively. In polyribosomes RNase occurred in both free and p-chloromercuribenzoate (pCMB)-liberated forms. The total activity was at the highest but the proportion of the free activity minimal in the granulation tissue during the maximal synthesis of collagen.

Animals↗
PubMed1984

Induction and characterisation of local (simple) calcergy in granulation tissue in the rat by lead acetate injection into polyurethane sponges.

Granulation tissue was allowed to grow into polyurethane sponges implanted subcutaneously in rats for 14 days prior to injection of saline (control) or lead acetate (PbAc) into the sponge centres. The reaction was studied for 21 days post-injection utilising sponge dry weight gain, histology and electron microscopy. Five hours after PbAc injection, calcification was demonstrable within the central tissue-free portion of the sponges. Calcification in granulation tissue was associated with collagen fibres and elicited a macrophage and multinucleated giant cell reaction. Mast cells were not found within sponges. Hydroxyapatite deposition was associated with an increase in sponge weight compared with controls. The injection of PbAc elicited calcification in granulation tissue in the same time scale reported for calcergy in mature connective tissue and the phenomenon of calcergy does not require the presence of collagen fibres or mast cells in its early stages.

Animals↗
PubMed2004

Tumour seeding in peritoneal wound sites in relation to growth-factor expression in early granulation tissue.

The purpose of these experiments was to identify growth factors produced during the formation of a peritoneal wound in relation to tumour cell seeding and stimulated growth in granulation tissue. Gelfoam(c) gelatin sponge was implanted in the mesenteric fan of nude mice to initiate the granulation process. Human HT29 colon carcinoma cells were inoculated intraperitoneally at various times after sponge implantation and tumour growth in granulation tissue was determined. RNA isolated from granulation tissue was used for polymerase chain reaction analysis of the expression of specific growth factors and receptors [vascular endothelial growth factor (VEGF), transforming growth factor-beta (TGF-beta) and lysophosphatic acid (LPA)], and for microarray analysis of differentially expressed genes in early vs. late granulation tissue. Inflammatory cells infiltrated the sponge within 1 day, followed by fibroblasts and the formation of an extracellular matrix. Tumour cell inoculation at 8 h to 3 days after sponge implantation resulted in extensive tumour formation in all cases. Inoculation at 10-28 days resulted in focal tumour growth in only 16-33% of the sponges. Low amounts of VEGF, TGF-beta(1-3), TGF-beta RIII and LPA receptors 1,2 were detected in early granulation tissue, with increased expression from day 10. Microarray analysis identified additional differentially expressed genes that may stimulate tumour take and growth in early granulation tissue.

Animals↗
PubMed1997

The effects of interleukin-1 and prostaglandin E2 on accumulation of collagen and steady-state levels of pro alpha 1(I) collagen messenger RNA in experimental granulation tissue in rats.

The effects of human interleukin 1 beta (IL-1 beta) and prostaglandin E2 (PGE2) on experimental granulation tissue in rats and on granulation tissue cells in culture were studied. IL-1 beta and PGE2 were injected into subcutaneously implanted sponges during the first 3 days after implantation. The rate of collagen synthesis in fibroblasts was measured as synthesis of protein-bound 3H-hydroxyproline. The steady-state levels of pro alpha 1(I) and pro alpha 1(III) collagen chain mRNAs were estimated by Northern transfer analyses. By 7 days postoperatively IL-1 beta had decreased the hydroxyproline content of granulation tissue. PGE2 decreased non-significantly the amounts of hydroxyproline, but the steady-state levels of pro alpha 1(I) and pro alpha 1(III) collagen chain mRNAs were slightly elevated. In IL-1 beta-treated fibroblast cultures collagen production decreased by 15% and following PGE2 treatment by 34% compared with the controls. The latter effect could be abolished by indomethacin. Indomethacin alone stimulated collagen production by 40%. In vivo IL-1 decreases the formation of normal granulation tissue. This effect may be partly due to stimulation of secretion of PGE2.

Animals↗
PubMed2001

Enhancement by histamine of vascular endothelial growth factor production in granulation tissue via H(2) receptors.

1. Roles of histamine in the production of vascular endothelial growth factor (VEGF) in the carrageenin-induced granulation tissue in rats were analysed in vitro and in vivo. 2. Incubation of the minced granulation tissue in the presence of histamine (1 and 10 microM) increased the content of VEGF protein in the conditioned medium in a time- and concentration-dependent manner. The levels of VEGF mRNA in the minced granulation tissue were also increased by histamine in a concentration-dependent manner. 3. The increase in the content of VEGF protein in the conditioned medium by histamine (10 microM) was suppressed by the H(2) receptor antagonist cimetidine (IC(50) 0.37 microM), but not by the H(1) receptor antagonist pyrilamine maleate, the H(3) receptor antagonist thioperamide or the cyclo-oxygenase inhibitor indomethacin. 4. The histamine-induced increase in the content of VEGF protein in the conditioned medium was inhibited by the cyclic AMP antagonist Rp-cAMP (IC(50) 6.8 microM), and the protein kinase A inhibitor H-89 (IC(50) 12.5 microM), but not by the protein kinase C inhibitors Ro 31-8425 and calphostin C or the tyrosine kinase inhibitor genistein. 5. Simultaneous injection of cimetidine (400 microg) and indomethacin (100 microg) into the air pouch of rats additively reduced the carrageenin-induced increase in VEGF protein levels and angiogenesis in the granulation tissue as assessed by using carmine dye. 6. These findings indicate that histamine has an activity to induce VEGF production in the granulation tissue via the H(2) receptor-cyclic AMP-protein kinase A pathway and augments angiogenesis in the granulation tissue.

Animals↗
PubMed1975

Collagen development in granulation tissue as compared with collagen of skin and aorta from injured and non-injured rats.

Granulation tissue in rats was produced by subcutaneous implantation of viscose cellulose sponges. Granulomas, aortae, and skin samples were taken 4, 8, 14, 22, 33, and 42 days after the sponge implantation and compared with age-matched non-operated rats. 14C-proline was given 4 hours before death to animals killed on day 0, 14, and 42. The 14C-OH-proline activity in salt insoluble collagen was higher in granulation tissue and aorta than in skin. This indicates a faster formation, or an increased stability of the intermolecular cross-links in granulation tissue and aorta, than in skin. The percentage of free OH-proline was than in skin, reflecting a relatively increased collagen degradation in granulation tissue. An increased collagen degradation may also, in part, explain a registered higher alpha/beta ratio in collagen from granulation tissue than from skin, as well as the increase in alpha/beta ratio in the older granulomas. The sponge implantation did not affect the collagen of aorta and skin, but caused a decrease in the dry weight of aorta and skin, and an increase in the number of granulocytes in the blood.

Animals↗
PubMed1998

[Quantitative determination of cell composition of human granulation tissue by fluorescence activated cell sorting (FAC)].

Granulation tissue of normal and non-healing human wounds showed a similar distribution pattern of the cell populations investigated by FACS analysis, whereas only non-healing wounds revealed a reduced density of cells and intercellular matrix. Thus, supporting the thesis that impaired wound healing is not caused by changes of the cellular distribution pattern of granulation tissue, but possibly by lessened cell function.

Cell Count↗
PubMed1998

[Response of the granulation tissue to acetylcholine and noradrenaline during denervation].

Granulation tissue from the wounds of back of both paws was studied in rats on 7th day of healing following crushing of right sciatic nerve and after repeated applications of 0.2 g/l of acetylcholine (Ach) and noradrenaline (NA). In control group (rats with intact nerves) applications of Ach intensified inflammatory reaction and negatively affected the state of regenerating skin tissues: the effect of NA consists in promoting fibroblastic and leukocytic reactions. Simultaneous crushing of right sciatic nerve and infliction of the wound amplified the pathologic reaction in the wounds of denervated rats as compared to that in animals who did not undergo denervation, leading to rapid ulceration. NA administration caused negative consequences in wounds both in right and left sides. Crushing of the nerve was performed 7 days prior to wound infliction and on day 7 of the study of neurodystrophic processes has shown that Ach influence on denervated and non denervated wounds was positive, while NA influence was negative. After reinnervation adreno- and cholinoreactivity of granulation tissue was partially normalized both on the right and left sides.

Acetylcholine↗
PubMed1999

Expression of vascular endothelial growth factor in exuberant tracheal granulation tissue in children.

Prolonged tracheotomy and endotracheal intubation often induce symptoms of airway obstruction and delay decannulation and extubation. Bronchoscopic examination of patients undergoing these treatments usually shows the presence of exuberant (pseudopapillary or nodular) granulation tissue occupying the airway lumen. An immunohistochemical analysis was undertaken of vascular endothelial growth factor (VEGF) expression in exuberant tracheal granulation tissue (n=17) obtained from children treated with prolonged tracheotomy or endotracheal intubation. Increased levels of VEGF protein and mRNA were expressed mainly by tracheal epithelial cells that migrated to cover the granulation tissue and partly by pericapillary macrophages in this tissue, whereas normal tracheal epithelium did not express VEGF. The VEGF expression level correlated significantly with the severity of the exuberant granulation tissue response (p=0.0018). As VEGF induces angiogenesis and vascular permeability, characteristics of granulation tissue, and plays a pivotal role in granulation tissue development, enhanced VEGF expression may be involved in the development of exuberant tracheal granulation tissue.

Adolescent↗
PubMed2002

Low molecular weight hyaluronic acid prevents oxygen free radical damage to granulation tissue during wound healing.

Hyaluronic acid protects granulation tissue from oxygen free radical damage and stimulates wound healing, but its molecular weight prevents it from permeating the epidermal barrier A low molecular weight hyaluronic acid preparation is able to permeate the skin, but it is unknown whether or not it retains the scavenging effects of oxygen free radicals in granulation tissue. Our experiments were conducted in rats with excisional or incisional wounds. Wound contraction over 11 days and breaking strength on the fifth day were measured. Oxygen free radical production was induced by intraperitoneal administration of two different xenobiotics: phenazine methosulfate and zymosan. The wounds were treated topically with low molecular weight hyaluronic acid (0.2%) cream or placebo. In the incisional wound group, the effects of superoxide dismutase were also determined. Absolute controls received wounds and placebo but no xenobiotics. Wound healing was significantly slower in the xenobiotic group than in the control groups. These effects were strongly reduced by topical administration of low molecular weight hyaluronic acid (0.2%) cream and in incisional wounds by topically injected superoxide dismutase. Low molecular weight hyaluronic acid is effective as the native compound against oxygen free radicals. Its pharmacological effects through transdermal administration should be tested in appropriate models.

Granulation Tissue↗
PubMed1998

Conservative treatment of vaginal vault granulation tissue following total abdominal hysterectomy.

OBJECTIVE: To study the incidence, symptoms and spontaneous regression rate of vault granulation tissue in relation to their sizes following total abdominal hysterectomy for benign conditions. METHODS: Prospective descriptive study; 352 patients who underwent total abdominal hysterectomy for benign conditions between September 1995 and April 1996 were included. All patients with vault granulation tissue were followed up until the 20th week after the operation. The main outcome measures were incidence of vault granulation tissue, symptoms, sizes of lesions, spontaneous regression rate and relationship between size and regression rate. RESULTS: The incidence of vault granulation tissue was 34%. Nearly 60% of the lesions were < or = 5 mm. Spontaneous regression occurred in 52% of the cases. If the lesion was < or = 5 mm the chance of it to completely disappear was 72% whereas the same would happen in only 33% if the lesion was > 5 mm (P < 0.01, significant). Although only 7% of the patients with lesions < or = 5 mm had symptoms as compared to 18% of those with lesions > 5 mm; the difference was not statistically significant. CONCLUSIONS: Vault granulation tissue is a common complication, occurring in approximately one-third of patients who had total abdominal hysterectomy. The results of our study suggests that if the lesions are small (< or = 5 mm) it would be reasonable to leave them alone as few give symptoms and most regressed spontaneously; saving the patients' time, inconvenience, expenses and discomfort.

Female↗
PubMed1990

Granulation tissue that developed after a minor trauma in a psoriatic patient on long-term etretinate therapy.

Synthetic analogues of retinoic acid, isotretinoin in particular, are known to cause granulation tissue in the nail sulcus and healing cystic acne. We observed granulation tissue that developed in a psoriatic patient on long-term oral etretinate therapy (30 mg/day for 3 years), another synthetic analogue of retinoic acid. In August of 1988, the patient, a 44-year-old male, hit his lower leg against a wooden stick, resulting in a laceration. At that time he had relatively limited patches of psoriasis, but his skin was generally thin with telangiectasia, even in areas without psoriasis, probably due to the long-term use of oral etretinate and topical steroid. In spite of treatment with topical disinfectants and oral antibiotics, the wound progressed into granulation tissue surrounded by erythema and multiple punctate erosions with marked secretion of a clear exudate. The histological findings of the granulation tissue included the presence of proliferating microvessels and a relatively dense cell infiltration with a predominance of plasma cells on the sparse edematous connective tissue. Based on these findings, the rash was considered to be retinoid-induced granulation tissue. As compared with previous reports, our case had the following characteristics: development of rash after minor trauma, rash on the lower leg, eosinophil infiltration into the rash. We believe that long-term users of oral etretinate should be cautioned about the potential for delayed wound healing and the formation of granulation tissue.

Adult↗
PubMed1995

Increased collagen degradation by experimentally-induced granulation tissue inoculated with bacteria.

Periodontitis is characterized by asymptomatic periodic collagen degradation, which is accompanied by the formation of granulation tissue induced by bacteria. The lesions sometimes contain micro-organisms and/or micro-abscesses that are of unknown significance. The aim of this study was to determine whether bacteria in a sterile granulation tissue could enhance its collagenolytic capacity. The formation of granulation tissue was induced by implanting a cellulose sponge in the subcutaneous tissue in the back of the rat. Bacteria were injected every other day into the sponge from day 8 to day 18. The cell-dependent degradation of a homologous 3H-collagen powder enveloped in the sponge was measured by the radioactivity of the urine excreted 8-18 days after the implantation. The injections increased the excretion of radioactivity by about 40% compared with the controls (n = 8, p < or = 0.005), but caused no clinical signs of acute infection or inflammation. On day 18, 2 days after the last injection of bacteria, no bacteria or increased cell infiltration were observed in the granulation tissue. The appearance of the latter could not be distinguished from that of the control tissues injected with buffer alone. It seems reasonable to assume that the increased collagen degradation results from enhanced activity of phagocytes, which may also be related to an increased release of tissue-destructive proteases and free oxygen radicals into the extracellular space. In conclusion, brief recurrent episodes of bacteria in granulation tissue can increase its collagen degrading-capacity. The latter may be due to augmented cell activity in the tissue. This response seems to have some features comparable to the pathogenesis of episodic periodontitis, e.g., by mimicking the collagen degradation.

Aggregatibacter actinomycetemcomitans↗
PubMed1992

Effect of endothelin-1 on croton oil-induced granulation tissue in the rat. A pharmacologic and immunohistochemical study.

BACKGROUND: To date no attempts have been made to determine the role of the endothelial cell derived product, endothelin-1 (ET-1) in granulation tissue development. This study investigates the cellular immunolocalization of ET-1 and its pharmacologic effect on myofibroblast-mediated rat croton oil-induced granulation tissue contraction. EXPERIMENTAL DESIGN: The distribution, cellular localization and temporal production of ET-1 in the tissues was determined by immunohistochemistry at days 7, 14, 21, and 28. The contractile response of the granulation tissue to ET-1 was tested over the same time period, and it effects modified by use of calcium antagonists. The pharmacologic profile was correlated to the ultrastructural development of contractile fibroblast-like cells within the tissue. RESULTS: Endothelin-1 caused reversible concentration-dependent contraction of the granulation tissue. The 21-day granulation tissue was the most responsive, with a maximum increase in tension of 458.9 +/- 41.1 mg; this response could be inhibited by use of calcium antagonists. Of the calcium antagonists tested, verapamil (1 x 10(-4) M) was the most potent inhibitor, giving a 43% reduction in maximum amplitude of the response. It is suggested that entry of extracellular calcium via the L-type potential operated calcium channel, is involved in ET-1 induced responses in contractile fibroblast-like cells or myofibroblasts. Ultrastructural analysis showed a correlation between the pharmacologic sensitivity of the tissue and the development of contractile fibroblast-like cells. The number of cells expressing the phenotypic characteristics of a myofibroblast increased with time, and were first observed at day 7. Immunohistochemistry revealed the presence of increasing numbers of ET-1 labeled cells throughout the time course of study. The ET-1 positive cells were localized to the capillaries. Immunolabeling of serial sections with the rodent endothelial cell specific lectin, Bandeiraea simplicifolia isolectin B4 and factor VIII-related antigen, confirmed the specific localization of ET-1 to endothelial cells. CONCLUSIONS: We present evidence that ET-1 may be an endogenous modulator of myofibroblast-mediated granulation tissue contraction and that the use of calcium antagonists could afford a possible therapeutic control in the treatment of fibrocontractive diseases.

Animals↗