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Possible pathogenesis of painful intervertebral disc degeneration.

STUDY DESIGN: We collected the specimens of lumbar intervertebral disc (i.e., the symptomatic degenerative disc) from patients with discogenic low back pain to study the histopathologic features and growth factor expressions. OBJECTIVES: To study the pathogenesis of disc degeneration, meanwhile discriminating between common disc degeneration (aging disc) (i.e., black asymptomatic disc, not clinically relevant) and painful disc degeneration (i.e., symptomatic disc, clinically relevant). SUMMARY OF BACKGROUND DATA: The pathogenesis of intervertebral disc degeneration is poorly understood, mainly because of the difficulty to establish the experimental model with good reproducibility. Recently, the popularity of spinal fusion leads to more opportunities to obtain disc specimens, which could be applied to explore the pathogenesis of disc degeneration with modern biologic techniques. METHODS: There were 21 specimens of lumbar intervertebral discs from 15 patients with discogenic low back pain during posterior lumbar interbody fusion, 16 aging discs from patients without low back pain, and 10 normal discs as control collected for the study of their histopathologic features, as well as the expressions of basic fibroblast growth factor (bFGF) and its receptor (Flg), transforming growth factor-beta1 (TGF-beta1) and its receptor (TGF-betaRI) by immunohistochemistry. The distribution of macrophages and mast cells was also noted. Proliferating cell nuclear antigen was assessed to evaluate proliferating activities of disc cells. RESULTS: The distinct histologic characteristic of the disc from the patient with discogenic low back pain was the ingrowth of vascularized granulation tissue along torn fissures, extending from the external layer of the anulus fibrosus into the nucleus pulposus. The immunohistochemical staining showed that there were strong expressions of bFGF and TGF-beta1 and their receptors, as well as a strong expression of proliferating cell nuclear antigen in the zones of granulation tissue in the painful discs. However, there were only weak expressions in the nongranulation tissue zones in the painful discs and aging discs, and no expression in the control discs. In addition, abundant macrophages and mast cells were found in the granulation tissue zones of painful discs but absent in the nongranulation tissue zones of painful discs or aging discs and the normal control discs. CONCLUSIONS: The findings indicated that degeneration of the painful disc might originate from the injury and subsequent repair of anulus fibrosus. Growth factors, such as bFGF and TGF-beta1, macrophages and mast cells might play a key role in the repair of the injured anulus fibrosus and subsequent disc degeneration.

Adult↗

Role of mesenchymal cell death in lung remodeling after injury.

Repair after acute lung injury requires elimination of granulation tissue from the alveolar airspace. We hypothesized that during lung repair, signals capable of inducing the death of the two principal cellular elements of granulation tissue, fibroblasts and endothelial cells, would be present at the air-lung interface. Bronchoalveolar lavage fluid obtained from patients during lung repair induced both fibroblast and endothelial cell death, while fluid obtained at the time of injury or from patient controls did not. The mode of cell death for endothelial cells was apoptosis. Fibroblast death, while morphologically distinct from necrosis, also differed from typical apoptosis. Only proliferating cells were susceptible to the bioactivities in lavage fluid, which were trypsin sensitive and lipid insoluble. Histological examination of lung tissue from patients after lung injury revealed evidence of apoptotic cells within airspace granulation tissue. Our results suggest that cell death induced by peptide(s) present at the air-lung interface may participate in the remodeling process that accompanies tissue repair after injury.

Acute Disease↗

Histological characterization of a delayed wound healing model in pig.

Chronic wounds, such as venous ulcers and pressure ulcers, frequently remain unresponsive to currently available treatments. Several animal models of wound healing have been published, including models of impaired healing developed to mimic the clinical condition of chronic wounds better. We used a delayed wound healing model in the pig that uses irradiation of the skin prior to creation of the surgical wounds and characterized it histologically. Radiation was used on one side of the back prior to making four full-thickness wounds on each side. Clinical observations were performed to record granulation tissue, reepithelialization, and wound area as a function of time. Histology data were obtained at 1, 2, 3, and 4 weeks, and slides were stained with hematoxylin and eosin for general observations. Immunohistochemistry was performed using laminin as a marker for blood vessels, and the number, size, and circularity of blood vessels found in the granulation tissue were measured. Our results show that this model causes a delay in wound healing that is mostly apparent between days 7 and 15. Granulation tissue took more time to form and fill the wounds on the irradiated side, and blood vessels were slower to develop. Blood vessels were larger and more irregular in shape on the irradiated side than on the control side. After 2 weeks, healing resumed, indicating that the induced damage was not irreversible. These results suggest that this model can be used to test the effects of therapeutic approaches intended to treat chronic wounds.

Animals↗

Myocardial apoptosis associated with the expression of proinflammatory cytokines during the course of myocardial infarction.

To clarify the role of myocardial apoptosis associated with the expression of proinflammatory cytokines in human myocardial infarction (MI), we have analyzed the expression of apoptosis positive for single-stranded DNA (ss-DNA) antibody, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-8 in 147 samples of infarcted myocardial tissue from 65 patients. ss-DNA-positive apoptotic nuclei were found mainly in cardiomyocytes in the border zones and granulation tissue cells in the infarct foci. The ss-DNA index (SI) of cardiomyocytes (average 0.13%) peaked at stage II (established myocardial necrosis), the value being significantly higher than at stages III (macrophage infiltration), IV (granulation formation), and V (scar formation) (P<0.05), whereas the SI of granulation tissue (average 0.08%) at stages III, IV, and V showed no significant differences between the three stages. These results suggest that cardiomyocyte apoptosis in the border zone is responsible for cellular loss in the acute stage of MI, whereas granulation tissue apoptosis may not be involved in the process of ventricular remodeling. TNF-alpha was expressed in cardiomyocytes in the border zones of infarct foci, but no significant positive correlation was found between SI and TNF-alpha index in cardiomyocytes (r=0.08, P = 0.37), suggesting that TNF-alpha does not serve as a direct trigger of cardiomyocyte apoptosis in vivo. The number of IL-8-positive cells peaked at stage II, and IL-8-myeloperoxidase-double-positive neutrophils were frequently detected, indicating that infiltrating neutrophils are the predominant source of IL-8 in the infarcted myocardium. These results suggest that, in human MI, TNF-alpha produced by cardiomyocytes does not play a critical role in their apoptosis, and that IL-8 produced by neutrophils is responsible for the subsequent accumulation and activation of neutrophils, thus increasing the degree of myocardial damage.

Aged↗

Relative proportions of mononuclear cell types in periodontal lesions analyzed by immunohistochemistry.

In this study, we investigated the relative proportions of infiltrating mononuclear inflammatory cells in sections of granulation tissue from periodontitis lesions in both adult periodontitis (AP) and early onset periodontitis (EOP) patients. We utilised a set of cluster of differentiation (CD) antigen-specific monoclonal antibodies to detect different cell types within the tissues. These included anti-CD 20 (B cells), anti-CD 3 (pan T cells) and anti-CD 45RO (memory T cells), anti-CD 4 (helper T cells) anti-CD 8 (suppressor T cells) and anti-CD 68 (monocyte/macrophage). Biopsies of granulation tissue were obtained from 9 patients with adult periodontitis (AP), from 10 patients with early onset periodontitis (EOP) and for comparative purposes, biopsies of gingival tissue from 4 patients with AP. A significantly greater number of T cells (p < 0.05) were observed in EOP and gingival sections than in AP sections. In addition, a greater number of B cells were observed in the granulation tissues than in the gingiva (p < 0.05). The relative numbers of B cells (CD 20). T cells (CD 3) and macrophages (CD 68) were expressed as a percentage of their combined total for each of the patient groups and indicated that the proportion of B lymphocytes was greater in AP sections than in EOP or gingival sections (p < 0.02). The proportion of T cells was lower in the AP periodontitis sections than in the EOP periodontitis sections (p < 0.05). There were no significant differences in the proportion of macrophages between the 3 categories of tissue specimens. The relative ratios of B cells (CD 20) to T cells (CD 3) and B cells (CD 20) to memory T cells (CD 45RO) and macrophages (CD 68) to T cells (CD 3) and memory T cells (CD 45RO) were analyzed and indicated that there was a significant increase in the B to T cell ratio in AP sections compared to EOP and gingival sections (p < 0.02). There was also a significant increase in the macrophage to T cell ratio in AP sections as indicated by CD 68 to CD 3 ratios (p < 0.05). There were no differences regarding the relative proportions of memory T cells or in the ratios of CD 4+ to CD 8+ T cells in the different disease categories. In conclusion, these differences in the relative proportions of B cells, T cells and macrophages may reflect a difference in the immunopathology of AP and EOP.

Adult↗

Differences in second-intention wound healing between horses and ponies: macroscopic aspects.

Second-intention healing of deep wounds was studied in 5 horses and 5 ponies. Standardised wounds were created on the distal limbs and hind quarters. Wounds on the metatarsi extended onto the metatarsal bone; the depth of the wounds in the femoral biceps muscle was 18 mm. The wound margins were marked by tattoos. Photographs were taken at weekly intervals to determine the wound area. The relative contribution of contraction and epithelialisation to wound closure was quantified by means of the tattoos. Swelling of the limbs was measured; and regularity and aspect of the granulation tissue were semi-quantitatively scored. Second-intention wound healing occurred significantly faster in ponies than in horses, and muscle wounds healed significantly faster than metatarsal wounds. These marked differences reflected the greater contribution of contraction to wound healing. Moreover, demarcation was seen earlier and a healthy granulation bed developed more rapidly in ponies, whereas in horses the granulation tissue remained irregular and purulent for longer. Healing of the metatarsal wounds of horses differed markedly from that of all other wounds: these wounds increased to almost twice their original size in the first 2 weeks, exuberant granulation tissue was persistent, epithelialisation started later, and contraction played a minor role in wound closure. Limb swelling was greater in horses than in ponies. Periosteal new bone formation was more extensive, and was active over a longer period in the metatarsal bones of horses than of ponies. From this study it is concluded that second-intention healing of deep wounds occurs faster in ponies than in horses. This difference can be largely attributed to a more pronounced and faster wound contraction in ponies than in horses. Therefore, attempts to improve second-intention wound healing in clinical practice should be directed at stimulation of wound contraction.

Animals↗

Prolonged intubation injuries of the larynx: endoscopic diagnosis, classification, and treatment.

Laryngeal trauma from prolonged endotracheal intubation occurs in patients of all ages. Most changes are superficial and heal quickly. Injuries that are found consistently during intubation include nonspecific changes, edema, granulation tissue, ulceration, and other miscellaneous injuries. In this paper significant, severe, and lasting trauma of the larynx has been classified on the basis of the known factors in pathogenesis, observations made at endoscopy, and photographic documentation. This classification has required introduction of new descriptive terminology: "tongues of granulation tissue," "ulcerated troughs," "healed furrows," and "healed fibrous nodule." During intubation the degree of injury can be precisely assessed under general anesthesia by using telescopes for image magnification, thus assisting a decision whether to continue intubation or perform tracheotomy to minimize long-term morbidity. Changes that are found after extubation result from granulation tissue, ulceration, or a combination of both and have been illustrated on flow charts; a knowledge and understanding of these sequelae allows them to be identified by both indirect and direct laryngoscopy so that treatment can be planned.

Acute Disease↗

[Autoradiographic study of the rate of collagen synthesis under conditions of stimulation of the wound process].

A study was made of the rate of the tropocollagen synthesis by the granulation tissue fibroblasts and of its passage into the intercellular space in control animals and under conditions of stimulation of the wound process by potassium orotate, one of the pyrimidine series derivatives. It appeared that the process of tropocollagen synthesis became accelerated under the effect of the stimulant; collagen fiber precursor appeared in the intercellular space earlier than in control and became included into the fibrous structures of the granulation tissue, this correlating with the intensification of the RNA synthesis in the fibroblast nuclei and an accelerated passage of the newly-synthesized RNA from the nucleus into the cell cytoplasm under analogous conditions. There was noted no sharp excess of collagen in the granulation tissue of animals given potassium orotate.

Animals↗

Antifibrinolytic additives to fibrin glue for laparoscopic wound closure in urinary tract.

BACKGROUND AND OBJECTIVES: Fibrinolytic activity of urine may rapidly degrade fibrin glue used in the urinary tract, thereby limiting tissue adhesion. The goals of this study were to verify the ability of antifibrinolytic agents to delay the degradation of fibrin glue in the urinary tract and to assess the results of this delay on subsequent wound healing. MATERIALS AND METHODS: In 25 domestic pigs, a 3.5-cm incision in the urinary bladder was left open (N = 6) or closed laparoscopically with fibrin glue alone (N = 6), fibrin glue containing aprotinin 5000 KIU/mL (N = 6), or fibrin glue containing aprotinin 2500 KIU/mL with (N = 4) or without (N = 3) aminocaproic acid 12.5 mg/mL. At harvest 7 days later, the bladder was tested for leakage. Histologic features were scored by a pathologist blinded to the closure method. RESULTS: There were no significant differences among the groups in the amount of leakage at harvest. Significant fibrin glue material in the wound was noted more often in the pigs treated with fibrin glue plus aprotinin (7 of 13) than in the fibrin glue-only group (0 of 6; P = 0.04). The presence of significant fibrin material in the wound correlated well with absence of granulation tissue (P < 0.001), such that granulation tissue bridging the wound edges was found more often in the fibrin glue-only group (6 of 6) than in the groups treated with fibrin glue plus aprotinin (4 of 13; P = 0.01). CONCLUSIONS: Although aprotinin +/- aminocaproic acid did delay the degradation of fibrin glue used to close a bladder wound, it was associated with inhibition of granulation tissue in the glued wound. These findings suggest that aprotinin alone and aprotinin plus aminocaproic acid are not useful additives to fibrin glue used for wound closure in the urinary tract.

Aminocaproates↗

Achilles tendinosis is associated with sprouting of substance P positive nerve fibres.

OBJECTIVES: To identify and characterise nerve fibres and inflammatory alterations in painful Achilles tendinosis and thus gain evidence about the origin of pain in Achilles tendinosis. METHODS: The composition of 10 tendon samples from patients with a prior history of painful Achilles tendinosis and 10 samples from patients with spontaneously ruptured tendons but no previous pain was compared by immunohistochemistry and conventional histology. RESULTS: The presence of granulation tissue was shown in 8/10 cases of Achilles tendinosis. Nociceptive substance P (SP) positive nerve fibres were significantly increased, and an inflammatory infiltration comprising B and T lymphocytes was found. Additionally, small foci with iron positive haemosiderophages, indicating prior microtraumatic events, were found in 6/10 samples. None of the spontaneously ruptured tendons contained granulation tissue or haemosiderophages. Inflammatory infiltration in these patients consisted almost exclusively of granulocytes and SP positive nerve fibres were decreased. The density of sympathetic nerve fibres did not differ in the two conditions. CONCLUSION: Achilles tendinosis is associated with the presence of granulation tissue, haemosiderophages, and SP positive nerve fibres, which may transmit the clinically pertinent pain. Achilles tendinosis may be caused by repeated microtraumata with ensuing organisation that is accompanied by sprouting of nociceptive SP positive nerve fibres.

Achilles Tendon↗

Penetration of macrophage ribonuclease into fibroblasts and the effects on nucleic acid and collagen metabolism.

RNAase isolated from macrophage culture medium was labelled with 3H-acetic anhydride. The acetylation density of 1.8 acetyl residues/10(4) dalton RNAase was achieved. After just 5 mins' incubation of granulation-tissue slices with 3H-Ac-RNAase, the enzyme had entered fibroblasts, and after 20 min there was only slight increase of the radioactivity. After 1 h incubation 32% of the ingested RNAse was in the nuclei, 23% in the cytosol and about 2% in RER. After the same period of incubation with 3H-Ac-RNAase, 47% of nuclear RNA of the fibroblasts was lost, as compared with the control incubation, and the amount of cytosol RNA increased by about 40%. During a 3-h incubation, in low concentrations, the biologically active macrophage RNAase stimulated. 3H-thymidine incorporation into DNA of proliferative granulation-tissue slices. Thus it was concluded that the fibrogenic effect of the macrophage RNAase on the granulation-tissue fibroblasts takes place through the RNA metabolism and the main target of the enzyme in the fibroblasts is the nuclear RNA.

Acetylation↗

Pathology of chronic otitis media.

A review of 800 pathological temporal bones collected from autopsy cases revealed 333 ((41.6%) to have some type of otitis media; purulent otitis media (52.5%), serous otitis media (6%), mucoid otitis media (4.5%), and chronic otitis media (36.9%). The 123 temporal bones with chronic otitis media were further studied and found to have granulation tissue, cholesteatoma, cholesterin granuloma, bone changes, and fibrosis. Other findings included tympanic membrane perforation, tympanosclerosis, metaplasia of the epithelium with subepithelial glandular formation, suppuration, labyrinthitis, and evidence of complications of chronic otitis media (meningitis, subdural abscess, brain abscess, petrositis, and endolymphatic hydrops). From this study it was concluded: 1) chronic otitis media occurred quite frequently, from a histological standpoint, in the absence of tympanic membrane perforation; 2) granulation tissue in temporal bones was found much more frequently in chronic otitis media than was cholesteatoma; and 3) complications and sequelae of otitis media tended to occur more commonly secondary to granulation tissue than to cholesteatoma.

Adult↗

The inflammatory reaction in an experimental model of open wounds in the rat. The effect of arachidonic acid metabolites.

The study concerned the effect of arachidonic acid metabolites on the inflammatory reaction in granulation tissue of open wounds in rats. Metabolites or inhibitors were applied in a wound chamber attached to circular, open, full-thickness skin wounds 5 days post-wounding. The adjacent wound served as control. Blood flow, albumin extravasation and accumulation of polymorphonuclear leucocytes (PMNLs) were measured in the granulation tissue. Prostaglandin E2 (PGE2 5.7 microM) increased blood flow and albumin extravasation by 95 and 16%, respectively, without affecting PMNLs. Leukotriene B4 (LTB4 2.7 microM) increased PMNL accumulation by 142% without altering albumin extravasation. Indomethacin (28 microM, repeatedly) did not affect blood flow or albumin extravasation, but increased PMNL accumulation by 21%. Methylprednisolone (3.3 mM, repeatedly) reduced blood flow and albumin extravasation by 29 and 31%, respectively, without influencing PMNLs. The granulation tissue obviously responds to exogenous PGE2 and LTB4. Endogenous arachidonic acid metabolites seem to play only a minor role in the inflammatory process in this model.

Animals↗

Pathology of otitis media.

Otitis media is characterized by inflammation of the middle ear. The pathologic changes seen in this condition tend to occur on a continuum, progressing from acute and subacute stages to the chronic phase, in which irreversible tissue damage is observed. The earliest morphological changes involve the lamina propria of the middle ear mucosa and include increased capillary permeability, edema, and leukocytic infiltration. During the late acute to subacute stages, the mucosa also tends to show a marked increase in numbers of ciliated and secretory epithelial cells. As the inflammatory process enters the chronic phase, there is a continuing shift in the population of infiltrating leukocytes toward increasing numbers of mononuclear cells that secrete substances that facilitate tissue destruction and fibrosis. There is also development and proliferation of granulation tissue, which is intimately involved in the process of bone erosion. As granulation tissue matures, it becomes denser and less vascular--a process that leads to permanent fibrosis and formation of adhesions that may significantly compromise middle ear function. Other pathologic entities occasionally associated with chronic otitis media include cholesteatoma, cholesterol cysts and granuloma, and tympanosclerosis, all of which may contribute to irreversible alterations of middle ear structure.

Bone Resorption↗

The effects of sialic acid on the gene expression of fibrillar collagens: different changes in normal and fibrotic scar derived fibroblasts.

OBJECTIVE: To investigate the effect of free sialic acid on collagen gene expression in fibroblasts. DESIGN: Cell culture study. SETTING: University hospital, Finland. CELL LINES: Human granulation tissue fibroblasts, human hypertrophic scar fibroblasts and human keloid fibroblasts. INTERVENTIONS: Treatment of cell cultures with 3 microM, 30 microM and 300 microM N-acetyl-neuraminic acid. MAIN OUTCOME MEASURES: The measurement of steady state level of mRNA for type I and type III collagen. RESULTS: Fibroblast lines react dissimilarly under the influence of sialic acid. Granulation tissue fibroblasts showed decrease in the gene expression of type I and III collagen, while keloid fibroblasts contrastingly showed an increase. Hypertrophic scar derived fibroblasts showed no change. CONCLUSIONS: Sialic acids may decrease collagen gene expression in granulation tissue and that disturbed wound healing in diabetics and smokers may in part be due to direct effect of sialic acids on fibroblasts. Sialic acids may in part induce keloid formation.

Cells, Cultured↗

The effects of sialic acid on the gene expression of fibrillar collagens: different changes in normal and fibrotic scar derived fibroblasts.

OBJECTIVE: To investigate the effect of free sialic acid on collagen gene expression in fibroblasts. DESIGN: Cell culture study. SETTING: University hospital, Finland. CELL LINES: Human granulation tissue fibroblasts, human hypertrophic scar fibroblasts and human keloid fibroblasts. INTERVENTIONS: Treatment of cell cultures with 3 microM, 30 microM and 300 microM N-acetyl-neuraminic acid. MAIN OUTCOME MEASURES: The measurement of steady state level of mRNA for type I and type III collagen. RESULTS: Fibroblast lines react dissimilarly under the influence of sialic acid. Granulation tissue fibroblasts showed decrease in the gene expression of type I and III collagen, while keloid fibroblasts contrastingly showed an increase. Hypertrophic scar derived fibroblasts showed no change. CONCLUSIONS: Sialic acids may decrease collagen gene expression in granulation tissue and that disturbed wound healing in diabetics and smokers may in part be due to direct effect of sialic acids on fibroblasts. Sialic acids may in part induce keloid formation.

Cells, Cultured↗

Effect of tranilast oily gel on carrageenin-induced granulation in rats.

Tranilast (TL) oily gels consisting of hydrogenated soybean phospholipid and fatty-acid ester were prepared, and the inhibitory effect of the gels on the growth of granulation tissue were evaluated in a carrageenin-induced rat granulation model. By the application of 0.1 and 0.2% TL oily gel, the weight of granulation tissue was significantly reduced to 64 and 55%, respectively, of control value. Furthermore, these gels reduced their respective hydroxyproline content to 64 and 51% of the control. On the other hand, the inhibitory effect of 10% TL ointments, which are clinically used for the treatment of keloids and hypertrophic scars as hospital preparations, was much lower than that of the oily gels. In addition, the application of 0.1 and 0.2% oily gel led to high concentration (0.1% gel, 168+/-18 microg/g; 0.2% gel, 221+/-16 microg/g) of TL in the dermis as compared with the 10% TL ointments. These results suggest that TL oily gels may be a useful topical formulation for the treatment of keloids and hypertrophic scars.

Administration, Topical↗

The open bone graft for septic nonunion.

Fifteen patients with actively draining septic nonunions were treated by a two-stage protocol consisting of (1) thorough and, if necessary, repeated debridement of nonviable bone, necrotic soft tissue, and dense scar tissue followed by stabilization with an external skeletal fixator; and (2) transplantation of cancellous bone into the exposed bone after it had become lined with granulation tissue. The graft, consisting only of fresh autogenous cancellous bone, is kept moist with physiologic irrigating solution throughout the granulation tissue stages of healing. The fractures were immobilized in fixators for an average of 7.5 months, until early maturation of the graft was complete. Some important technical considerations include: (1) waiting until all exposed bone is covered with granulation tissue; (2) applying biplanar external fixation; and (3) inserting a bone graft tissue mass larger in diameter than the bone being replaced. Thirteen fractures were healed and free of infection at follow-up evaluation, while two patients underwent amputation.

Adult↗