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PubMed1995

Collagen matrices attenuate the collagen-synthetic response of cultured fibroblasts to TGF-beta.

Transforming growth factor-beta, a potent modulator of cell function, induces fibroblasts cultured on plastic to increase collagen synthesis. In 5- and 7-day porcine skin wounds, which have minimal to moderate collagen matrix, respectively, transforming growth factor-beta and type I procollagen were coordinately expressed throughout the granulation tissue. However, in 10-day collagen-rich granulation tissue type I procollagen expression diminished despite persistence of transforming growth factor-beta. To investigate whether collagen matrix attenuates the collagen-synthetic response of fibroblasts to transforming growth factor-beta, we cultured human dermal fibroblasts in conditions that simulate collagen-rich granulation tissue. Therefore, human dermal fibroblasts were suspended in attached collagen gels and collagen and noncollagen production was assayed in the absence and presence of transforming growth factor-beta. Although transforming growth factor-beta stimulated collagen synthesis by fibroblasts cultured in the collagen gels, these fibroblasts consistently produced less collagen than similarly treated fibroblasts cultured on plastic. This phenomenon was not secondary to nonspecific binding of transforming growth factor-beta to the collagen matrix. Fibroblasts cultured in a fibrin gel responded to transforming growth factor-beta similarly to fibroblasts cultured on plastic. Using immunofluorescence probes to type I procollagen, we observed that transforming growth factor-beta increased type I procollagen expression in most fibroblasts cultured on plastic, but only in occasional fibroblasts cultured in collagen gels. From these data we conclude that collagen matrices attenuate the collagen synthetic response of fibroblast to transforming growth factor-beta in vitro and possibly in vivo.

Animals↗
PubMed1979

The role of contractile proteins in wound healing and fibrocontractive diseases.

During the healing of an open wound, the majority of granulation tissue fibroblasts (myofibroblasts) acquire morphological, biochemical, pharmacological, and immunological characteristics typical of contractile cells. The presence of contractile proteins and the appearance of gap junctions between several myofibroblasts make them similar to cultivated fibroblasts; these have been proven to develop in vitro a contractile force similar to that exerted by granulation tissue during wound contraction. These observations suggest that myofibroblasts are responsible for granulation tissue contraction. Epidermal cells moving over an open wound also develop a contractile apparatus and many cellular connections in the form of gap junctions. These changes may be the morphological support for epithelial cell movements. The presence of gap junctions between myofibroblasts and healing epidermal cells shows that granulation tissue contraction and epithelial cell movement are probably synchronized rather than individual phenomena.

Actomyosin↗
PubMed2003

Topical vascular endothelial growth factor in rabbit tracheal surgery: comparative effect on healing using various reconstruction materials and intraluminal stents.

OBJECTIVES: The effect of topical vascular endothelial growth factor (VEGF) on post-surgical tracheal healing using various reconstruction materials was studied, with particular regard to prevention of granulation tissue or fibrosis. METHODS: Twenty-four New Zealand White rabbits underwent survival surgery using autograft patches (n=6), xenopericardium patches (n=6), intraluminal Palmaz wire stents (n=6), and controls (n=6). Autograft and pericardial half-patches were soaked in topical VEGF (5 microg/ml over 30 min) and saline before reimplantation. Stents and controls received circumferential injections of VEGF and saline in the tracheal wall. At 1-4 months postoperatively, specimens of sacrificed animals were stained with anti-VEGF antibody, followed by morphological and immunohistochemical examination. RESULTS: Rabbits with autografts and controls fared well until planned sacrifice. After xenopericardium repair, obstructive intraluminal granulation tissue led to early sacrifice in three rabbits. Stent insertion led to earlier death from airway obstruction in all six rabbits. Topical VEGF reduced granulation tissue after pericardial repair and fibrosis in all repairs except in stents. Remarkably, VEGF-pretreated half-patches and saline half-patches stained similarly high for VEGF, suggesting also local production of VEGF, probably in plasmacells, and in submucosal glands. CONCLUSIONS: Autograft repair induces the least granulation tissue and fibrosis, and the best healing pattern. Stents rapidly induced critical airway obstruction, unhindered by VEGF, leading to premature death. Tracheal pretreatment with topical VEGF reduces postoperative fibrosis after autograft and pericardial patch repairs, and reduces granulation tissue after xenopericardium repair. In time, VEGF is probably locally produced, although its potential role in tracheal healing remains to be established.

Administration, Topical↗
PubMed2002

A comparison of rat tracheal transplant models: implantation verses anastomotic techniques for the study of airway rejection.

BACKGROUND: In rodent models, investigators have transplanted donor tracheas into a recipient rat's abdomen or s.c. tissue to study airway rejection. We describe a modification of this model, which provides improved histology to study the airway injury related to obliterative bronchiolitis. METHODS: The standard technique of implanting the donor trachea was compared to a model in which a tracheal Y graft was created by anastomosis of the donor trachea to the recipient airway. Syngeneic and allogeneic tracheal grafts (Lewis and Brown Norway rats) were harvested at 2 and 4 weeks using each model (eight groups). RESULTS: Gross patency at the tracheal anastomosis grafts was 100%. All donor tracheas, which were implanted without an anastomosis, were occluded with mucus (syngeneic) or granulation tissue (allogeneic). Syngeneic implant grafts demonstrated significantly less lumenal granulation tissue 35.3%+/-32 than the allograft implant group (95.3%+/-9.2, P=0.0005 at 4 weeks). The anastomotic allograft group demonstrated significantly less lumenal granulation tissue 48.3%+/-23.7 when compared with the implanted allograft group (P=0.003). The implanted allograft demonstrated a severe loss of epithelial integrity by 2 weeks (16.7%+/-38), which progressed to complete loss by 4 weeks (P=0.0001 and P=0.0001 vs. native). This loss was significantly more than that of the anastomotic group at 2 weeks (89.5%+/-13, P=0.004) and 4 weeks (88.3+/-29, P=0.005). CONCLUSIONS: The rat tracheal allograft anastomosed to the recipient airway demonstrated less lumenal granulation tissue obstruction and better preservation of epithelial integrity than an implant allograft, suggesting that an open airway improves assessment of transplant-related changes associated with rejection.

Anastomosis, Surgical↗
PubMed1990

Left ventriculotomy of the heart: tissue repair and localization of collagen types I, II, III, IV, V, VI and fibronectin.

The reparative process following left ventriculotomy was investigated immunohistochemically using anti-type I, II, III, IV, V and VI collagen antibodies, and anti-fibronectin antibody. Wound healing began with proliferation of young fibroblasts positive for type I, III and V collagens at the wound margin; vascular granulation tissue then grew into the injured myocardium followed by deposition of fibrous components immunoreactive with type I and III. At 30 days after operation when almost the entire thickness of the myocardium at the wound was replaced by fibrosing granulation tissue, a small cluster of adipocytes appeared around capillaries at the wound margin. The granulation tissue was gradually replaced by the adipose tissue with establishment of a fibrous union at the subendocardium by 90 days. In addition to type I and III collagens, type VI collagen was detected in a fine fibrillary pattern along thick collagen fibre bundles in the fibrous tissue and around the adipocytes. Fibronectin was distributed diffusely in the granulation tissue and gradually decreased with increase of the fibrous components. These results indicate that the ventriculotomy was finally repaired in the form of a fibrous scar, particularly in the endocardium. There was marked infiltration of adipose tissue in the damaged myocardium. Presumably type VI collagen, as well as type I and type III collagens, plays an important role in wound union.

Animals↗
PubMed1988

Inflammatory reaction and blood flow in experimental wounds inoculated with Staphylococcus aureus.

Wound healing and granulation tissue formation can be accelerated by inoculation with live pathogenic microorganisms. For further elucidation of this phenomenon the present work was undertaken to study the effects of Staphylococcus aureus microorganisms on the inflammatory reaction and blood flow in developing granulation tissue in rats. Cylindrical hollow sponge implants were used as an inductive matrix for the growth of granulation tissue. In control animals 1 ml of wound fluid was withdrawn from the central dead space of the implant immediately after implantation and replaced with 1 ml of physiological saline. In experimental animals the implants were injected with live staphylococci, 10(2) or 10(5) microorganisms/ml. Wound fluid was analyzed 3, 7, 10 and 14 days after implantation, whereas measurements of local blood flow and albumin extravasation in the granulation tissue were made after 7 days. Implants inoculated with 10(5) organisms developed infection with pus formation while implants contaminated with 10(2) organisms showed no infection. In wound fluid specimens collected from the infected implants correlation between the number of polymorphonuclear leukocytes and prostaglandin E2 concentration was statistically significant. The most prominent finding in contaminated but uninfected implants was an enhanced local blood flow. This may explain some of the mechanisms leading to S. aureus-induced acceleration of wound healing.

Animals↗
PubMed1993

Indications for an expandable metallic stent for tracheobronchial stenosis.

An expandable metallic stent was used in 9 patients with tracheobronchial stenosis. Of the 8 patients with malignant stenosis, 6 had extrinsic compression and 2 had intraluminal tumor invasion. The 1 patient with nonmalignant stenosis had postreconstruction bronchomalacia and granulation tissue affecting different parts of the tracheobronchial tree. The expandable metallic stent successfully dilated tracheobronchial stenosis due to extrinsic tumor compression and malacia. However, it was not effective for stenosis due to intraluminal tumor invasion or granulation tissue because of the growth of tumor or granulation tissue between the wires of the stent. However, an expandable metallic stent covered with Dacron mesh was effective in 1 patient with intraluminal tumor invasion because tumor growth was blocked by the mesh. We conclude that an expandable metallic stent is effective for tracheobronchial stenosis due to extrinsic tumor compression, but not for stenosis due to intraluminal tumor invasion or granulation tissue.

Adult↗
PubMedDate not supplied

[Morphological characteristics of inflammatory polyps of the large intestine in children].

Inflammatory polyps of 32 children were studied morphologically. Inflammatory polyps comprised more than 20% of all removed polyps in 1983-2002. They were second among common polyps in children after juvenile polyps. Typical location of inflammatory polyps was the rectum. Characteristic morphological features of inflammatory polyps in children are predomination of the inflammatory component represented by granulation tissue. In contrast to juvenile polyps granulation tissue in inflammatory polyps does not contain glands but may contain foreign bodies and giant cells. About one third of the inflammatory polyps in children in this study was associated with mucosal prolapse syndrome evidenced by proliferation of smooth muscle cells and fibrous tissue in the stroma of polyp glandular component.

Child↗
PubMed1981

[Wound healing of liver and kidney after repeated thermocoagulation (author's transl)].

Two focal thermolesions were made on rats liver and kidney at an interval of 4 weeks, and comparative histological and cell kinetic studies were performed on the wound healing process after a single and repeated thermolesion(s). The wound healing after the thermolesion took place very gradually. An active granulation tissue was found till the 4th--5th week after the thermolesion. The resorption of the necrotic carbonized material was particularly difficult. Only after 6--8 weeks did the fibrous scarring start. The histological analysis of the granulation tissue and of the scar tissue showed no significant difference in cell components and cell density after the single and after the double thermolesion(s). Autoradiographically, however, it was shown that the proliferation maximum of fibroblasts in the granulation tissue and of mesenchymal cells in the surrounding uninjured tissues after the double thermolesions occurred 24 h later than after the single thermolesion. Furthermore, the labelling index of the fibroblasts in the granulation tissue was lower after double lesions than after the single lesion. Once the scar tissue was formed, there was no significant difference between the labelling indices of mesenchymal cells after single and double lesions. By the present study it was suggested that delayed wound healing after thermolesions may be caused by decreased proliferation activity of mesenchymal cells, combined with delayed resorption of carbonized material. An implication of altered T cell system in the delayed wound healing was also discussed.

Animals↗
PubMed1987

Effect of Withania somnifera on glycosaminoglycan synthesis in carrageenin-induced air pouch granuloma.

The effect of W. somnifera on glycosaminoglycan synthesis in the granulation tissue of carrageenin-induced air pouch granuloma was studied. W. somnifera was shown to exert significant inhibitory effect on incorporation of 35S into the granulation tissue. The uncoupling effect on oxidative phosphorylation (ADP/O ratio reduction) was also observed in the mitochondria of granulation tissue. Further, Mg2+ dependent ATPase activity was found to be influenced by W. somnifera. W. somnifera also reduced the succinate dehydrogenase enzyme activity in the mitochondria of granulation tissue.

Adenosine Triphosphatases↗
PubMedDate not supplied

Effects of pressure on bone resorption in the middle ear of rats.

Laminaria, a hygroscopic seaweed, was used to induce pressure within the rat tympanic cavity. Resorption of the bulla and cochlear walls occurred in all animals within 2 weeks. Cochlear fistulas were observed in four of nine animals after 2 weeks and in nine of 11 animals after 3 weeks. Preswelled laminaria inserted in the same area induced minimal bone resorption after 2 and 3 weeks. In animals given indomethacin following insertion of laminaria, both granulation-tissue formation and bone resorption were inhibited. Collagenase appeared localized in the inflammatory granulation tissue in the bone-resorption area, especially in fibroblasts, mononuclear cells, and osteoclasts. Results of this study suggested that pressure created by laminaria caused bone resorption by stimulating osteoclasts and granulation tissue.

Animals↗
PubMedDate not supplied

Involvement of proteolytic enzymes--plasminogen activators and matrix metalloproteinases--in the pathophysiology of pressure ulcers.

The role of matrix-degrading enzymes, particularly plasminogen activators and matrix metalloproteinases, in the acute wound healing response has been the focus of many scientific studies. Only recently have these classes of endogenously produced proteinases been studied with regard to their involvement in the chronic wound environment. Using both in situ histologic zymography and immunohistochemical techniques, we examined the distribution of plasminogen activators and matrix metalloproteinase in the granulation tissue of pressure ulcers. Using in situ histologic zymography, urokinase was found to be the predominant plasminogen activator activity in the chronic wound granulation tissue, with little or no tissue-type plasminogen activator activity. These results were confirmed with the use of immunohistochemical techniques. In contrast, tissue-type plasminogen activator was found to be constitutively expressed in normal skin. Levels of matrix metalloproteinases were also found to be elevated in the granulation tissue of pressure ulcers. Immunohistochemical localization of leukocyte-associated proteinases (PMN elastase and cathepsin G) suggested a highly inflamed environment within the pressure ulcer granulation tissue. These results suggest a highly proteolytic environment within the chronic wound.

Journal Article↗
PubMed1993

Immunoelectron microscopic localization of transforming growth factor beta 1 and latent transforming growth factor beta 1 binding protein in human gastrointestinal carcinomas: qualitative difference between cancer cells and stromal cells.

Transforming growth factor beta 1 (TGF-beta 1) is secreted as an inactive complex associated with latent TGF-beta 1 binding protein (LTBP). Tissue localization of these proteins has not been fully understood in human pathological conditions. We examined the immunohistochemical localization of TGF-beta 1 precursor (proTGF-beta 1) and LTBP in carcinomas and granulation tissue in the human gastrointestinal tract at the light and electron microscopic levels. In normal tissue, endothelial cells and granulocytes sporadically showed immunoreactivity for proTGF-beta 1, while epithelial cells were all negative. In cancer tissue, both cancer cells and stromal cells (fibroblasts, macrophages, and endothelial cells) were positive for proTGF-beta 1, more frequently in diffuse-type gastric carcinomas than in differentiated-type adenocarcinomas. Immunoelectron microscopy revealed that proTGF-beta 1 was localized in rough endoplasmic reticulum and perinuclear cisternae in fibroblasts, macrophages, and endothelial cells in cancer stroma and in fibrous granulation tissue. In contrast, the intracellular localization of proTGF-beta 1 in carcinoma cells was predominantly observed in the cytosol (cytoplasmic matrix). This finding suggests disarranged or blocked intracellular transportation of proTGF-beta 1 in cancer cells. The immunoreactivity for LTBP was not observed in the normal epithelial cells. It was localized in cancer stroma, not in cancer cells. Ultrastructurally, LTBP was located in the extracellular matrix around fibroblasts and smooth muscle cells. The intracellular immunoreactivity for LTBP was observed in rough endoplasmic reticulum of fibroblasts and smooth muscle cells, the same as in granulation tissue. These results suggest that gastrointestinal carcinoma cells produce no or a small amount of LTBP in vivo. Our investigation suggests that extensive fibrosis in both cancer stroma and granulation tissues may be promoted by TGF-beta 1 mainly secreted from stromal cells.

Carrier Proteins↗
PubMed1999

Cell division, synthetic capacity and apoptosis in periodontal lesions analysed by in situ hybridisation and immunohistochemistry.

In this study, we investigated the synthetic and proliferative activity of infiltrating mononuclear cells in sections of granulation tissue from periodontitis lesions in both adult periodontitis (AP) and early onset periodontitis (EOP) patients. We also investigated the role of apoptosis in the remodelling of the inflamed tissue. We utilised a Ki-67 antigen specific antibody and a histone messenger RNA (mRNA) probe to detect cells undergoing cell division in the sections. Oligonucleotide probes for 28S ribosomal RNA and for the detection of poly A mRNA were utilised to detect cells with synthetic capacity. Apoptosis was determined using terminal transferase labelling of fragmented DNA with Biotin labelled dUTP. Biopsies of granulation tissue were obtained from 9 AP patients, from 10 EOP patients and for comparative purposes, biopsies of gingival tissue from 4 patients with AP. There were no differences regarding the relative proportions of cells with synthetic capacity or in the numbers of dividing cells in the periodontitis tissue sections. However, we observed an increase in the number of dividing cells in the AP granulation tissues compared to the AP gingival sections and that these cells were predominantly fibroblast like in appearance. Apoptotic cells consisted mainly of connective tissue cells; mainly fibroblasts with few if any leukocytes being apoptotic other than polymorphonuclear leukocytes. Only a few cyto-phagocytic macrophages were ever observed in the gingival and granulation tissues. We conclude that the turnover of infiltrating leukocytes in inflamed periodontal tissue is low, that they probably arrive at this site by recruitment from distant lymph nodes, and that neither cell division nor programmed cell death significantly alter the numbers of inflammatory cells. On the other hand, fibroblast apoptosis and cell division occur within the periodontium as these are typical processes in the normal turnover and remodelling of these tissues.

Adult↗
PubMed1999

Wound healing of human skin transplanted onto the nude mouse after a superficial excisional injury: human dermal reconstruction is achieved in several steps by two different fibroblast subpopulations.

It has been established that human skin grafted onto the nude mouse is able to regenerate after being subjected to a full-thickness wound. In the present work, we sought to determine the cells involved in the connective tissue repair process following superficial wounding. Two months after transplantation, superficial wounds were made at the center of the graft using mechanical dermabrasion. At various times thereafter, ranging from 2 days to 6 weeks, healing grafts were harvested and processed for immunohistological study with species-specific and cross-reacting antibodies directed against human or mouse antigens. The grafted human skin regenerated according to the following series of events. First, the human dermis underneath the scab became devoid of human fibroblasts while the surrounding human dermis preserved its own characteristics. The TUNEL reaction on earlyphase healing wounds indicated that apoptosis occurred steadily within this area and could be the mechanism by which cells disappeared. Moreover, cell death was reduced when the wound was covered with an occlusive dressing. The human dermis beneath the wound was then invaded by mouse cells which deposited type I collagen on the human extracellular matrix and produced mouse granulation tissue at the surface above it. Human keratinocytes migrated over the mouse granulation tissue to reconstruct the epidermis. Eventually, the mouse granulation tissue was progressively invaded by human fibroblasts, which formed a human neodermis. The overall process appeared to depend upon several successive epithelial-mesenchymal interactions, which were not species-specific. This suggests that myofibroblasts arise from a specific subpopulation of fibroblasts, probably located at the interface between the dermis and adipose tissue, and that the granulation tissue is eventually remodeled by another population of fibroblasts present in the human dermis.

Animals↗
PubMed1988

Type I and type III collagen content of healing wounds in fetal and adult rats.

Full-thickness, dermal wounds were surgically created on the dorsa of fetal rats on the 17th day of gestation. The granulation tissue which developed after 2 days (19 days of gestation) was harvested from six to nine animals and pooled and the collagen was extracted with 0.5 M acetic acid and acetic acid plus pepsin. The ratio of type III:type I collagen was estimated from densitometer scans of electrophoretically separated alpha-chains. Full-thickness (to fascia depth) wounds were also produced on the dorsa of adult rats and granulation tissue which had developed for different periods of time up to 30 days was excised. Relative proportions of type III and type I collagen were assessed in normal and granulation tissues taken from the adult rats. Both fetal and adult granulation tissues have elevated type III collagen content but normal fetal tissue has a much higher content of type III than does normal adult tissue.

Animals↗
PubMed2002

Lymph node infarction associated with infectious mononucleosis: report of a case resembling lymph node infarction associated with malignant lymphoma.

A completely infarcted lymph node should alert the pathologist to the high possibility of malignant lymphoma. The lymph node lesion of infectious mononucleosis (IM) shows marked histologic diversity and occasionally may be confused with malignant lymphoma. We report a rare case of IM showing extensive lymph node infarction whose lymph node lesion was similar to lymph node infarction associated with malignant lymphoma. This case describes a 32-year-old Japanese man who had signs and symptoms consistent with IM, which he was later proven serologically to have, but whose cervical lymph node showed extensive lymph node infarction with a thin area of granulation tissue beneath the capsule. The infarcted tissue contained numerous eosinophilic ghosts of large lymphoid cells. The thin granulation tissue was composed of numerous small lymphocytes, plasma cells, and histiocytes, in addition to large lymphoid cells including immunoblasts and granulocytes. CD20, CD3, and CD45RO immunostains revealed the mixed B- and T-cell nature of the ghosts of large lymphoid cells in the infarcted tissue as well as viable large cells in the granulation tissue. The patient was free from disease after 50 months' follow-up.

Adult↗
PubMed2005

A single-center 6-year experience with two types of pediatric tracheostomy.

OBJECTIVE: Among a wide variety of tracheostomy techniques, a vertical tracheal incision and a horizontal incision with creation of an inferior base tracheal flap have been favorized in children in the past. The aim of this study was to determine surgical and postoperative stoma complications after performing these two types of tracheal incision in tracheostomy in children. METHODS: A 6-year, prospective, observational cohort study was undertaken in 24 children (range, 0.03 month-15 years) at the Department of Otorhinolaryngology, University of Ulm. All children who underwent an elective tracheostomy were included in this study. Early and late local disorders in wound healing of the tracheal stoma and the clinical follow-up of both groups (Flap group and Vertical group) were analyzed. RESULTS: Formation of granulation tissue and tracheal stenosis were the most observed local disorders in both groups. Granulation tissue at the level of the stoma was the most frequently observed complication in the Flap group (4/12; 33%), whereas in the Vertical group only one child showed granulation tissue around the stoma (1/7; 14%). The difference between both groups was statistically not significant. The overall mortality rate 1 year after tracheostomy was 25% (6/24) and the tracheostomy-related death rate was 4% (1/24). An association of wound healing disorders with a feasible lethal outcome was not found after both tracheostomy types. There were no differences in the outcome between both tracheal incision types. CONCLUSIONS: Both types of tracheal incision proved to be a suitable surgical procedure for temporary or permanent tracheostomy in pediatric patients.

Adolescent↗