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Fibroblasts from wounds of different stages of repair vary in their ability to contract a collagen gel in response to growth factors.

Wound contraction is one function of granulation tissue which is critical to repair. This study compares the ability of fibroblast-like cells derived from granulation tissue of various ages to contract a tissue equivalent, or a collagen gel, and examines the influence of growth factors implicated in wound repair on collagen gel contraction by these different cell populations. Cells from older granulation tissue (21 and 28 days) have an enhanced ability to contract a tissue equivalent when compared to cells from younger granulation tissue (7 and 14 days) or normal rat skin fibroblasts. Transforming growth factor-beta 1 (TGF-beta 1) enhanced contractility most in those cells which had a greater basal contractile ability. While basic fibroblast growth factor (bFGF) alone had moderately stimulatory effects at low doses (0.1-1.0 ng/ml), higher doses (greater than or equal to 10 ng/ml) inhibited basal contraction. Pretreatment with bFGF followed by exposure to TGF-beta 1, with or without the continued presence of bFGF, delayed gel contraction by cells from skin and early granulation tissue, but bFGF enhanced TGF-beta 1 activity in highly contractile cells. Transforming growth factor-alpha moderately enhanced contraction by cells from older granulation tissue. While both TGF-beta 1 and bFGF enhanced wound repair, their differential effects on the fibroblast-like cell derived from granulation tissue of different ages suggest that phenotypic differences exist between these cell populations. In addition, our results predict significant interactions between polypeptide cytokines at the site of repair.

Animals↗

Expansion of fascial flaps: histopathologic changes and clinical benefits.

In order to meet the requirements of large defects created by sacral and trochanteric pressure ulcers, tensor fasciae latae and lumbosacral fasciocutaneous flaps were expanded with a silicone expander in six patients (10 flaps). In 8 of the flaps the location of pressure ulcers was trochanteric, and in 2 it was sacral. In each case the period of expansion was 4 weeks. Histopathologic examination after expansion showed an increase in the vascularity and overall thickness of fascia in both types of flaps. After 4 weeks of expansion, the perifascial areolar tissue was replaced with thick granulation tissue in the tensor fasciae latae flaps. This markedly vascular layer of granulation tissue interposed between the fasciae and the subcutaneous tissue augmented the internal matrix of the flap, thereby lowering the potential for shearing during flap elevation. Conceivably, owing to the absence of an areolar tissue layer in the lumbosacral fasciocutaneous flaps, no layer of granulation tissue was observed. The average thickness of the fibrous capsule formed around the expanders was 573.2 microns, which was composed of three structurally different zones. Prior tissue expansion obviously assisted primary closure of the flap donor site. In addition, it seems that the tissue-expansion process rendered the distal portion of fascial flaps more robust because of increased vascularity. It is therefore proposed that preparatory tissue expansion of fascial flaps has several advantages. The obvious benefits include the ability to close larger defects while closing the donor site primarily. As a result of this study, the additional benefits may include a reduction in the mechanical shear potential of these flaps and an improvement in their vascularity.

Adipose Tissue↗

[Wound healing in the donor areas in burn patients].

A connective tissue regenerate, presented by granulation tissue, appears over the smooth and even surface of operative wounds produced by the dermatome scalpel in the donor areas in the process of healing. Argentophilic membrane appears over the free granulation surface. Source of wound epithelium regeneration at the donor areas is largely the epithelium of the skin appendages. At the end of the third week, with adequate healing, process, the wound in the donor areas epithelializes. The process of healing of this wound may be impeded, when infection with exudate appears on the granulation tissue surface. Then epithelialization of the wound does not occur.

Adolescent↗

Repeated treatment with lidocaine/prilocaine cream (EMLA) as a topical anaesthetic for the cleansing of venous leg ulcers. A controlled study.

Repeated topical analgesia with EMLA 5% cream prior to the cleansing of venous leg ulcers was studied. Patients were randomly allocated to a series of 8 treatments with EMLA (n = 22) or to a control group (n = 21). A thick layer of the cream was applied to the ulcers for 30 min. At each of the 8 treatments, local reactions were assessed on a 4-point scale and pain from ulcer cleansing on a visual analogue scale. At the first and the last treatment the area of the ulcer was determined by mapping, a sample for a bacterial culture was taken and the amount of dead tissue, slough and granulation tissue present was assessed. Treatment with EMLA for 30 min significantly decreased the pain from cleansing of the leg ulcers and the frequency of post-cleansing pain. The analgesic effect remained unchanged with successive treatments. Repeated treatment with EMLA in leg ulcers would appear to be safe, as indicated by the absence of any serious untoward events. No statistically significant differences in local reactions or adverse effects on granulation tissue, ulcer area or bacterial flora were observed in the EMLA-treated patients compared with the control patients.

Adult↗

Accelerated tissue repair induced by micrococcus varians.

The present investigation was undertaken to study the effect of inoculated Micrococcus varians organisms on developing granulation tissue in rats. Subcutaneously implanted hollow cylindrical cellulose sponges were used as an inductive matrix for the growth of granulation tissue. The control implants were injected immediately after implantation with 1 milliliter of physiologic saline solution while the experimental implants were injected with a corresponding volume of saline solution containing live micrococci 10(7) microorganisms per milliliter. Cytologic and bacteriologic analyses of wound fluid aspirated from the central dead space of the implants were carried out three, seven and 14 days after implantation. Local blood flow and albumin extravasation were measured on day seven and granulation tissue grown into the implants was analyzed chemically on days seven and 14. No macroscopic infection with pus formation occurred, while Micrococcus varians was cultured from each inoculated implant. In the inoculated implants, the number of wound fluid neutrophils, granulation tissue blood flow and albumin extravasation increased significantly above the control level. Correspondingly, the amounts of granulation tissue deoxyribonucleic acid, nitrogen, collagen hydroxyproline, hexosamines and uronic acids in the inoculated implants exceeded significantly the control value on both days seven and 14. To conclude, inoculation of experimental wounds with nonpathogenic Micrococcus varians organisms enhanced local inflammatory reaction and blood flow, and promoted granulation tissue formation.

Animals↗

Morphometric studies on wound healing after systemic administration of adriamycin and local application of fibrin sealant. Application of a new wound healing model using spongiosa implants.

For investigations on the development of regenerative granulation tissue in wound healing a new model using bone spongiosa ("Kieler Spongiosa") implants is presented. Particular attention was devoted to developing a model which permits studies on wound healing without disturbance by foreign body reaction and infections. Two test groups of rats received four blocks of "Kieler Spongiosa" each in a symmetrical fashion in a paramedian region underneath the dorsal skin. The spongiosa blocks had previously been treated with glutaraldehyde to achieve cross-linkage of the collagenous structures of the surfaces of the spongiosa trabeculae. After one week (group 1) and two weeks (group 2) the animals were sacrificed. The spongiosa blocks were removed, fixed and evaluated in layered serial sections after decalcification. Two blocks which had been removed randomly from the back and front served for morphometric determination of the total volume of bony substance and the developed granulation tissue. Moreover, the cellular composition of the granulation tissue was morphometrically examined with regard to its content of capillaries, granulation tissue cells and inflammatory cells. The two other blocks were examined for DNA and hydroxyproline content of granulation tissue. Comparison of the two experimental groups yielded marked differences in spongiosa space infiltrated by granulation tissue and its composition. Our model was used to assess the influence of systemic administration of adriamycin and/or local application of a fibrin sealant system on granulation tissue formation and its morphologic structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Appearance of tenascin in healing skin of the mouse: possible involvement in seaming of wounded tissues.

Distribution of the extracellular matrix glycoprotein tenascin during wound healing in mouse skin was studied immunohistochemically. Within 24 hours after wounding, and preceding the formation of granulation tissue, tenascin appeared in the basement membranes beneath epidermis and hair follicles adjacent to the wound edges and in the wounded edges of cutaneous muscle layer. Granulation tissue began to form in the wound space at about 1-2 days and was immediately covered by epidermis. Tenascin first appeared in the periphery of the granulation tissue beneath healing epidermis and around the wounded edges of cutaneous muscle layer. Then the tenascin-positive area extended into the inner region of granulation tissue. At about 5-7 days, all of the granulation tissue was intensely stained with anti-tenascin serum. Tenascin immunoreactivity decreased as granulation tissue was replaced with reconstructed dermal tissue at 7-14 days. In most cases, tenascin staining persisted longest in the dermis beneath the healing epidermis and at the juncture of healing edges of cutaneous muscle layer. It disappeared at about 10-14 days after wounding. These findings suggest that tenascin may play an important role in the seaming of wounded tissues.

Animals↗

[Development of a radioligand assay for quantifying specific prostaglandin E1 binding in ischemic ulcers].

Ulcers of the lower extremities are of immense socioeconomical importance. Prevention and therapy of these trophic lesion are hence of great interest. In granulation tissue of ischemic ulcers Laser Doppler flow was previously shown to be higher compared to that in ischemic/adjacent skin or in ulcer without granulation tissue. Intravenous infusion of prostaglandin E1 significantly increased Laser Doppler flow. The present study was designed to test the hypothesis whether the increased baseline and prostaglandin E1-stimulated perfusion of granulation tissue is due to an increased number of prostaglandin E1-receptors in granulation tissue. Therefore, a radioligand binding assay was developed. In an initial pilot study the density of the prostaglandin E1-receptors in granulation tissue of ulcers was compared to that in ischemic/adjacent skin in 8 patients suffering from peripheral arterial occlusive disease requiring debridement or amputation of limbs because of ischemic lesions. The amount of specific binding sites detected was not significantly different between granulation tissue and ischemic/adjacent ulcer tissue. However it cannot be excluded that a possible difference might be detectable with more sensitive assays. In the future we hope to establish a more sensitive assay in order to be able to answer the initial question, whether there is a difference concerning the density of prostaglandin E1 receptor sites in granulation tissue and ischemic/adjacent skin.

Aged↗

Treatment of avascular ulcers with cytokine-induced tissue generation and skin grafting.

BACKGROUND: Recombinant platelet-derived growth factor (rPDGF-BB) stimulates migration and proliferation of fibroblasts and smooth muscle cells and induces the rapid development of granulation tissue. This study investigated the use of rPDGF-BB and skin grafting to heal avascular ulcers using a rabbit model. We further investigated the effect of a hyaluronic acid carrier and a vascular pedicle on rPDGF-induced tissue generation in this model. METHODS: Large avascular ulcers were created on both ears of New Zealand white rabbits. One ulcer was treated with topical rPDGF-BB, the other with control buffer. After 5 or 7 days, the amount of granulation tissue migration from the wound margin was measured, and the wounds were skin grafted. In another group of ulcers, rPDGF-BB treatment was combined with a hyaluronic acid disk or an intact central axial ear artery and vein. RESULTS: Whereas control wounds generated 1.00 +/- 0.27 mm and 1.75 +/- 0.25 mm of granulated tissue migration from the wound margin by days 5 and 7, respectively, rPDGF-BB treatment increased the amount of granulation tissue migration to 1.88 +/- 0.23 mm and 3.00 +/- 0.86 mm by days 5 and 7 after treatment, respectively (P <0.05 at both time points). Hyaluronic acid disks stimulated 2.50 +/- 0.22 mm of granulation tissue migration by day 7 in controls; when rPDGF-BB was added to the carrier, the migration increased to 4.50 +/- 0.29 mm from the wound margin (P<0.05). Granulation tissue migration was further increased with an intact vascular pedicle: 5.75 +/- 0.48 mm in controls versus 7.75 +/- 0.25 mm with rPDGF-BB treatment (P<0.01). Skin grafts applied to the treated ulcers failed to survive in all groups except those with intact vascular pedicles. CONCLUSIONS. This study demonstrates that rPDGF-BB can increase the amount of granulation tissue generated over an avascular wound. This tissue generation is enhanced by both a hyaluronic acid carrier and a vascular pedicle. A vascular pedicle was required for skin graft survival. This study supports the role of hyaluronic acid in rPDGF-BB induced tissue generation and the requirement of a direct blood supply for functional cytokine-induced tissue generation.

Animals↗

Humoral immune responses in periodontal disease may have mucosal and systemic immune features.

The humoral immune response, especially IgG and IgA, is considered to be protective in the pathogenesis of periodontal disease, but the precise mechanisms are still unknown. Immunoglobulins arriving at the periodontal lesion are from both systemic and local tissue sources. In order to understand better the local immunoglobulin production, we examined biopsy tissue from periodontitis lesions for the expression of IgM, IgG, IgA, IgE and in addition the IgG and IgA subclasses and J-chain by in situ hybridization. Tissues examined were superficial inflamed gingiva and the deeper granulation tissue from periodontal sites. These data confirm that IgM, and IgG and IgA subclass proteins and J-chain can be locally produced in the periodontitis tissues. IgG1 mRNA-expressing cells were predominant in the granulation tissues and in the gingiva, constituting approx. 65% of the total IgG-expressing plasma cells. There was a significantly increased proportion of IgA-expressing plasma cells in the gingiva compared with the granulation tissue (P < 0.01). Most of the IgA-expressing plasma cells were IgA1, but a greater proportion expressed IgA2 mRNA and J-chain mRNA in the gingival tissues (30.5% and 7.5%, respectively) than in the periodontal granulation tissues (19% and 0-4%, respectively). The J-chain or dimeric IgA2-expressing plasma cells were located adjacent to the epithelial cells, suggesting that this tissue demonstrates features consistent with a mucosal immune response. Furthermore, we were able to detect the secretory component in gingival and junctional epithelial cells, demonstrating that the periodontal epithelium shares features with mucosal epithelium. In contrast, deeper tissues had more plasma cells that expressed IgM, and less expressing IgA, a response which appears more akin to the systemic immune response. In conclusion, this study suggests that immune mechanisms involved in the pathogenesis of periodontitis may involve features of both the mucosal and systemic immune systems, dependent on tissue location.

Adult↗

Inhibition of wound contraction with locally injected lathyrogenic drugs.

BACKGROUND: Previous studies using systematically administered lathyrogens to inhibit wound contractures have produced inconsistent results. The purpose of this study was to investigate the effects of lathyrogenic drugs on wound contraction when injected locally. METHODS: Two symmetrical full-thickness wounds were made on the dorsum of either side of hairless (hr/hr) mice; thus, each animal served as its own control. Animals were divided into groups receiving daily local injections of beta-aminopropionitrile or D-penicillamine, or both beta-aminopropionitrile and D-penicillamine and normal saline vehicle (control side) for 5 or 10 days. The rate of contraction was determined by serial measurements of the surface area of each wound during the treatment period. At the end of the treatment period, the wounds were excised en bloc with the chest wall and prepared for blinded histological analysis. Granulation tissue thickness, number of fibroblasts in granulation tissue per unit area, number of inflammatory cells (neutrophils, lymphocytes, macrophages and mast cells) in subjacent muscle per unit area, and collagen deposition in subjacent muscle were determined. RESULTS: Wound contraction, granulation tissue thickness, and collagen deposition in subjacent muscle were decreased only in wounds treated with beta-aminopropionitrile plus D-penicillamine. Collagen deposition in subjacent muscle was also decreased in wounds treated with D-penicillamine alone. Neither drug alone nor the combination affected the number of inflammatory cells in subjacent muscle. Body weight was not affected by the experimental procedures. CONCLUSIONS: The combination of beta-aminopropionitrile and D-penicillamine is potentially useful for inhibiting contracture formation when injected locally.

Aminopropionitrile↗

Hypergranulation tissue: a nontraumatic method of management.

Granulation tissue above the periwound area is usually considered an impediment to wound healing. Although there is very little in the literature regarding hypergranulation tissue, the fact that there are numerous treatments by various wound clinicians demonstrates the recognition of its presence as a clinical problem. The paucity of published information prompted the authors to design a study to collect objective data on a treatment method they had found useful in their practices. This article explores the issue of hypergranulation and offers a nontraumatic method of management. A prospective non-controlled correlational study was undertaken with ten patients and twelve wounds using a polyurethane foam dressing to reduce hypergranulation tissue. The results demonstrated a significant decrease in height of 2 mm of granulation tissue from initial measurements to measurements taken two weeks later (p < 0.01).

Aged↗

Effects of hexose sugars: glucose, fructose, galactose and mannose on wound healing in the rat.

The effects of four hexose sugars (D-glucose, D-fructose, D-galactose, D-mannose) on the developing granulation tissue in rats were examined. Cylindrical hollow sponge implants were used as an inductive matrix for the growth of granulation tissue. In the test group, the implants were injected with 0.1 ml of solution containing the different hexoses in 0.01, 0.1 and 1 M concentrations daily for 7 days while the implants of the control groups were injected with 0.1 ml of phosphate-buffered saline solution only. Analyses of granulation tissue and wound fluid in the sponge implants were carried out 7 days after implantation. The results demonstrated that galactose caused a significant increase in the accumulation of granulation tissue as estimated by histological analyses, but no significant differences were observed in various chemical analyses. In striking contrast, statistically significant decreases were observed in the number of leukocytes in wound fluid, in the amount of DNA, RNA, collagen hydroxyproline, nitrogen, hexosamines and uronic acids in sponges treated with 0.1 or 1 M mannose, reflecting decreased granulation tissue formation. This effect was also observed in histological analyses of the specimens. There were no major changes in sponges treated with glucose or fructose. In summary, the findings of the present study demonstrate that galactose may enhance wound healing and mannose treatment inhibits the inflammatory reaction in wound healing and decreases granulation tissue formation in an experimental wound model.

Animals↗

[Effect of exogenous administration of platelet-derived growth factor and epidermal growth factor on duodenal ulcer healing in rats treated with indomethacin].

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) delay peptic ulcer healing through mechanisms that are still not entirely understood. Growth factors play a significant role in healing. AIM: To evaluate whether exogenous administration of platelet-derived growth factor (PDGF) reverses the effect of indomethacin in experimental duodenal ulcers in rats and to define the potential mechanisms involved in this process. METHOD: Duodenal ulcer was induced in male Wistar rats with acetic acid. The rats were then administered indomethacin (2 mg/kg/day), PDGF-BB (30 ng/100 g/day), epidermal growth factor (EGF) (50 /kg/day) or famotidine (positive control) or the possible combinations of these. Macroscopic area, reduction in microscopic diameter, epithelial and granulation tissue proliferation, collagen secretion by granulation tissue, and gastric acid secretion were analyzed. RESULTS: Indomethacin delayed duodenal ulcer healing by decreasing cellular proliferation and inhibiting collagen secretion. PDGF and EGF accelerated healing and reversed the effects of indomethacin. The mechanisms involved were associated with an increase in collagen proliferation and secretion without affecting gastric acid secretion. Famotidine also accelerated healing and reversed the effect of indomethacin, and these effects were associated with a marked inhibition of gastric acid secretion and increase in collagen secretion by granulation tissue. CONCLUSIONS: Exogenous administration of PDGF and EGF accelerated healing and reversed the harmful effects of indomethacin in an experimental model of duodenal ulcer.

Acetic Acid↗

Effect of cyclosporine on wound healing.

Two prophylactic immunosuppressive drugs, cyclosporine and methylprednisolone (MP), were compared for their effect on the in situ inflammatory reaction of granulation tissue formation and on wound healing. Granulation tissue was generated via implantation of viscous cellulose sponges in Sprague-Dawley rats. The rats were divided into six groups: One group received 40 mg/kg/day of cyclosporine, the second 10 mg/kg/day of cyclosporine, the third 2.5 mg/kg/day of cyclosporine, the fourth 12 mg/kg/day of MP, the fifth received the cyclosporine solvent, and the sixth group was given only saline. All drugs were given i.p. No reduction in the number of inflammatory cells was observed in the cyclosporine-treated sponges compared with the controls, whereas MP suppressed the inflammation strongly. Differential counts demonstrated a relative enrichment of macrophages in the cyclosporine-treated versus the MP-treated or control sponges. Chemical analyses of the sponge extracts agreed well with the cytological data: MP suppressed the total DNA content of the sponges, a marker of total cellularity, as well as the content of acid phosphatase and beta-glucuronidase, both markers of macrophages, but no such suppression was seen in the cyclosporine-treated sponges. The alkaline phosphatase content, a marker for granulocytes, was similar in all groups. A remarkable suppression in the contents of hydroxyproline, reflecting the amount of collagen, and in that of hemoglobin, reflecting the amount of neovascularization, was observed in the MP-treated sponges, whereas no such suppression--but possibly a slight enhancement of the second parameter--was observed in the cyclosporine-treated sponges. We conclude that, in contrast to MP, cyclosporine does not inhibit the inflammatory reaction of granulation tissue formation or the regenerative process of wound healing.

Acid Phosphatase↗

Cathepsin activity in cholesteatoma.

Collagenolytic cathepsin, presumed to play an important role in bone destruction of cholesteatoma, was investigated in cholesteatoma epithelium, subepithelial granulation tissue, skin from the bony external auditory meatus and, temporal bone. The enzyme extracted from tissues was proven to be lysosomal cathepsin B by SDS gel electrophoresis in the use of human type I and type III collagen. alpha-N-benzoyl-DL-arginine-2-naphthylamide HCl (BANA) was supposed to be specific for cathepsin B, and so BANA-hydrolase activity was measured as collagen-degrading cathepsin. The results showed that tissues had cathepsin B with its optimal pH 6.0, and that cathepsin B activity revealed a significant increase in the subepithelial granulation tissue. A strong activity of acid phosphatase found in the subepithelial granulation tissue seems to reflect the existence of an active metabolism of substances in the granulation tissue. These findings suggest that collagen is resorbed in the subepithelial granulation tissue in the presence of cholesteatoma.

Acid Phosphatase↗

Tumor necrosis factor alpha inhibits wound healing in the rat.

This work was undertaken to study the effects of tumor necrosis factor-alpha (TNF-alpha/cachectin) on developing granulation tissue in rats. Cylindrical hollow sponge implants were used as an inductive matrix for the growth of granulation tissue. In the two test groups the implants were injected daily for 4 days with a solution containing either 50 or 200 ng of TNF-alpha, while the implants of the control group were treated correspondingly with phosphate-buffered saline solution only. Analyses of granulation tissue and would fluid in the sponge implants were carried out 7, 14 and 21 days after implantation. In histological specimens the ingrowth rate of granulation tissue into the sponge was significantly lower after 7 days in the group treated with 200 ng of TNF-alpha. No such an effect was observed after 14 or 21 days. After 7 days, the mean amounts of nucleic acids reflecting cellularity in the granulation tissue decreased dose-dependently, but nonsignificantly, in the groups treated with TNF-alpha. Simultaneously, the accumulation of collagen hydroxyproline of the sponge was significantly lower in the group treated with 200 ng of TNF-alpha than in the controls (-30%, one-way analysis of variance). This effect was not observed after 14 or 21 days. No significant differences were detected in the amounts of nitrogen, hexosamines and uronic acids between the groups, reflecting unchanged accumulation of glycosaminoglycans in the developing granulation tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Topically applied CMT-2 enhances wound healing in streptozotocin diabetic rat skin.

Delayed wound healing is one of the complications of diabetes mellitus, exhibited by increased wound collagenase and decreased granulation tissues. The current study compared wound healing in normal and diabetic rats, and the effects of topically applied 1% or 3% concentrations of chemically modified tetracycline-2 (CMT-2) on 6-mm circular full-thickness skin wounds healed by secondary intention. On day 7 after wounding, tissues were removed for biochemical analysis and histology. The wound granulation tissue hydroxyproline was less in the untreated diabetic rat with increased collagenase and gelatinase. Treating the diabetic rat wounds with 3% CMT-2 increased the wound hydroxyproline and decreased activities of gelatinase and collagenase. There was a delay in wound filling by granulation tissue in diabetic rats. In CMT-2-treated diabetic rats, the volume of granulation tissue was greater than that in untreated diabetic rats. CMT-2 appears to normalize wound healing in diabetic rats and may be a valuable adjunct in the treatment of chronic wounds.

Administration, Topical↗