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PubMed1981

Onchocerciasis and glaucoma: ophthalmo-pathological aspects of the limbus and Tenon's capsule in 25 surgical patients from Ghana.

In a group of 25 Ghanian patients on whom trepano-trabeculectomy was performed, 14 patients had glaucoma simplex and 11 patients had glaucoma and onchocerciasis. Light-microscopical examination of tissue obtained at these operations showed: 1. there are no clear differences in the trabecular system between the 2 groups; 2. the post-trabecular outflow system is markedly abnormal in patients with glaucoma and onchocerciasis: there is infiltration round Schlemm's canal, the efferent veins and the vessels in Tenon's capsule. Microfilariae were also demonstrated in Tenon's capsule. In the discussion the necessity for further study is stressed.

Adolescent↗
PubMed2005

Comparative effects of TGF-beta 1 and TGF-beta 2 on extracellular matrix production, proliferation, migration, and collagen contraction of human Tenon's capsule fibroblasts in pseudoexfoliation and primary open-angle glaucoma.

PURPOSE: To comparatively investigate the effects of TGF-beta(1) and TGF-beta(2) on extracellular matrix production, proliferation, migration, and collagen contraction of cultured human Tenon's capsule fibroblasts derived from patients with pseudoexfoliation (PEX) syndrome, PEX glaucoma, primary open-angle glaucoma (POAG), and cataract. METHODS: Tenon's capsule fibroblasts obtained from four groups of patients were cultured and stimulated with different concentrations (0.1-10 ng ml(-1)) of TGF-beta(1) or TGF-beta(2) for up to 14 days. Cell proliferation was determined with the WST-1 colorimetric assay, cell migration by using the Transwell assay system, and collagen contraction by computerised analysis of three-dimensional collagen lattices and immunohistochemistry for alpha-smooth muscle actin expression. Expression and synthesis of extracellular matrix components (fibronectin, collagen types I and III) was assessed by enzyme-linked immunosorbent assays, by real-time RT-PCR, and by transmission electron microscopy. RESULTS: Both TGF-beta(1) and TGF-beta(2) in pathophysiological concentrations of 0.1-5 ng ml(-1) stimulated cell proliferation, migration, collagen contraction, alpha-smooth muscle actin expression as well as mRNA expression and secretion of fibronectin, collagen type I, and collagen type III by Tenon's fibroblasts derived from all groups of patients. TGF-beta stimulation occurred in a concentration-dependent manner with different peak activities associated with different fibroblast functions. There was some variability among the different groups of patients with an increased response of cells derived from PEX and POAG patients as compared to cataract patients. Although no statistically significant differences were found between both TGF-beta isoforms, TGF-beta(1) had a more pronounced stimulatory effect on expression and synthesis of extracellular matrix components including the production of elastic microfibrils, particularly in cells derived from patients with PEX syndrome/glaucoma. CONCLUSIONS: These findings suggest a significant contribution of TGF-beta(1) in addition to TGF-beta(2) to the conjunctival scarring process following glaucoma filtration surgery. Due to its pronounced fibrogenic potential, TGF-beta(1) may become another focus for targeting drug therapy, particularly in patients with PEX glaucoma.

Aged↗
PubMed2004

[The investigation of tranilast on the proliferation and migration of human Tenon's capsule fibroblasts].

OBJECTIVE: To investigate the effect of tranilast, N-(3,4-dimethoxycinnamoyl) anthramilic acid, on the proliferation and migration of human Tenon's capsule fibroblasts. METHODS: fibroblasts were cultured from Tenon's tissue of a glaucoma patient after trabeculectomy. The subcultured cells were incubated with DMEM medium containing different concentrations of tranilast for 72 h. The growth of fibroblasts was measured by methyl thiazlyl tetrazolium (MTT) assay and the cell count, and migration was evaluated by crutch method. The expression level of Protein kinase C (PKC) in fibroblasts was tested by immunohistochemical associated with image biological analysis (IBAS) methods. RESULTS: Treated with tranilast varying from 12.5 mg/L to 100.0 mg/L concentration, the proliferation of fibroblasts declined in a dose dependent manner. The migration of fibroblasts decreased from 40.20 +/- 5.83 to 22.50 +/- 4.21 and 9.80 +/- 2.14 cells/per field (P < 0.05) at 50.0 and 100.0 mg/L, respectively, and PKC expression was suppressed by tranilast from 0.2591 +/- 0.0038 to 0.2375 +/- 0.0106 and 0.1273 +/- 0.0573 Absorption value (P < 0.05) at 50.0 and 100.0 mg/L, respectively. CONCLUSION: Tranilast inhibited the proliferation as well as migration of fibroblasts in vitro, at least in part, by downregulation of PKC expression.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1995

The effect of topical cholinergic medications on human Tenon's capsule fibroblasts in tissue culture.

BACKGROUND: The prior long-term use of topical anti-glaucoma medications has been suggested as an adverse factor for the outcome of trabeculectomy. The mechanism of action is not known. This study investigates the effect of cholinergic medications on the proliferation and viability of human Tenon's capsule fibroblasts in tissue culture to see whether this may be one mechanism by which increased surgical failure occurs. METHODS: We examined the effect of two commercial pilocarpine products, pure pilocarpine hydrochloride, and pure benzalkonium chloride, at various dilutions, on the proliferation (as assessed by 3H-thymidine uptake) and viability (assessed microscopically) of human Tenon's capsule fibroblasts in tissue culture. RESULTS: None of the tested compounds stimulated the proliferation of fibroblasts in tissue culture. Three of the compounds inhibited proliferation, and all compounds had toxic effects on cell morphology. At equivalent dilutions of commercially available concentration, pure benzalkonium chloride and the commercial product containing it appeared more toxic and antiproliferative to cells in culture than pure pilocarpine hydrochloride and the preservative-free commercial product. CONCLUSIONS: These results show an antiproliferative and toxic effect of medications on fibroblasts in tissue culture. They do not support the theory that topical medications directly stimulate fibroblast proliferation. The possible relevance of these results for the outcome of glaucoma surgery is discussed.

Aged↗
PubMed1999

Collagen type I and III synthesis by Tenon's capsule fibroblasts in culture: individual patient characteristics and response to mitomycin C, 5-fluorouracil, and ascorbic acid.

PURPOSE: This study was performed to better understand the differences between patients in specific components of wound healing as it may pertain to glaucoma filtration surgery, including the use of antimetabolites. METHODS: Human Tenon's capsule fibroblasts were obtained at the time of glaucoma filtering surgery and established in individual cell cultures from 35 glaucoma patients. The dose-response to 5-fluorouracil (5FU) and mitomycin C (MMC) was determined. The individual cell lines were exposed to the antimetabolites and ascorbic acid with measurement of collagen type I and III production by an ELISA-type dot blot assay. These results were then statistically compared to the individual patient characteristics including age, race, previous surgery and medications, and type of glaucoma. RESULTS: 5-FU had little effect on collagen type I and III production or protein synthesis. MMC had an inhibitory effect on collagen secretion and total protein synthesis with increasing concentration. Photomicrographs of the cells after each treatment condition revealed characteristic morphologic changes when compared to controls. There was a large range of collagen type I and III production with correlation between the amounts of each collagen type secreted in response to the antimetabolites. However, there was no correlation with accepted risk factors for filtration failure. CONCLUSION: These antimetabolites act similarly on different cell lines in a nonspecific manner. The results suggest that the increased risk of filtration failure due to age, race, diagnosis, and previous conjunctival surgery is not due to differences in secretion of collagen types I and III by Tenon's capsule fibroblasts.

Adolescent↗
PubMedDate not supplied

Tucking the inferior oblique muscle into Tenon's capsule following myectomy.

PURPOSE: Myectomy of the inferior oblique muscle is a common procedure used to correct overaction of this muscle. Previous descriptions of the surgery have not discussed how the surgeon should handle the proximal muscle stump following myectomy. This study examined the effectiveness of inferior oblique muscle myectomy with tucking of the muscle into Tenon's capsule for treatment of inferior oblique muscle overaction. METHODS: The procedure was studied prospectively in 22 patients who underwent 32 inferior oblique muscle myectomies. In 18 patients, the intraoperative behavior of the inferior oblique muscle was recorded. Complete ocular motility examinations were performed before and after surgery. Success was defined as the elimination of inferior oblique muscle overaction and the elimination of hypertropia secondary to persistent ipsilateral inferior oblique muscle overaction in primary gaze. RESULTS: The surgery corrected inferior oblique muscle overaction in 94% of eyes. Hypertropia secondary to persistent ipsilateral inferior oblique muscle overaction was eliminated in 92% of patients. There was no correlation between outcome and the intraoperative behavior of the inferior oblique muscle. CONCLUSION: Tucking of the inferior oblique muscle stump into Tenon's capsule is recommended following inferior oblique myectomy. This procedure is safe and effective for correcting inferior oblique muscle overaction.

Connective Tissue↗
PubMed2003

Partial Tenon's capsule resection with adjunctive mitomycin C in Ahmed glaucoma valve implant surgery.

AIM: To verify if partial intraoperative Tenon's capsule resection (PTCR) with adjunctive mitomycin C is effective in developing thin, avascular blebs in eyes undergoing Ahmed glaucoma valve insertion, and to assess the efficacy and safety of this procedure. METHODS: A multicentre, prospective, alternating case assignment, investigator unmasked, parallel group, comparative interventional study was conducted in four Latin American countries (Argentina, Brazil, Colombia, and Peru). Ahmed glaucoma valve implant insertion with PTCR (group A) and without PCTR (group B) was performed in neovascular glaucomatous eyes without previous surgery. Adjunctive mitomycin C (MMC) was used in both groups. Patients were examined 1 day, 10 days, 1 month, 2 months, 3 months, 6 months, and 1 year following the surgery. Intraocular pressure (IOP) and the appearance of the bleb were evaluated at each examination. Appearance of the bleb was classified at both the 1 month mark and last examinations into one of three groups: flat and vascularised; elevated avascular; or elevated and not avascular. RESULTS: 92 eyes from 92 patients were included in the study. The preoperative mean IOP was 50.0 (SD 10.5) mm Hg in group A and 48.4 (11.7) in group B (p>0.05). Statistically significant IOP reductions were observed at all periods of follow up. 12 months after surgery, the mean IOP was 17.2 (5.0) mm Hg in group A and 18.3 (8.7) mm Hg in group B (p>0.05). A hypertensive phase occurred in 40.0% in group A and in 46.8% in group B (p>0.05). At the 1 month and the final follow up, the blebs in all eyes were considered elevated and not avascular. The success rate (IOP</=21 mm Hg) at 1 year after surgery was 70.4% in group A and 77.7% in group B (p>0.05). Overall, 74.2% of the patients achieved an IOP </=21 mm Hg and 55.2% an IOP</=17 mm Hg, with or without additional medication administered to lower IOP. The incidence of complications was similar in both groups. CONCLUSIONS: In eyes undergoing Ahmed valve implantation for neovascular glaucoma, PCTR with MMC augmentation showed no additional benefits or complications over MMC augmentation alone; no avascular bleb was obtained with this technique. The incidence of a hypertensive phase was lower than reported in previous studies.

Aged↗
PubMed1999

Mitomycin C-induced apoptosis in cultured human Tenon's capsule fibroblasts.

To investigate the mitomycin C-induced apoptotic cell death of fibroblasts, the primarily cultured human Tenon's capsule fibroblasts were exposed to a clinically used dosage of 0.4 mg/ml of mitomycin C for 5 minutes. TUNEL (TdT-mediated dUTP-biotin nick end labeling) assay and electron microscopic studies were performed to determine the extent of mitomycin C-induced apoptosis. A flow cytometric study was performed to quantify the apoptotic cell population over time. The TUNEL stains were positive and electron microscopy showed features of apoptotic cell death in some fibroblasts 3 and 5 days after treatment. Flow cytometric analysis using Annexin V-propidium iodide double staining detected apoptotic cells 3 days after treatment. These apoptotic cell populations increased at 4 days and were sustained for one week. This study revealed that the clinical effects of mitomycin C on fibroblasts may be mediated not only by antiproliferative but also apoptotic cell death to some degree. Therefore, the apoptotic cell death of fibroblasts induced by mitomycin C should be considered to properly understand the mechanism of wound healing after trabeculectomy with adjunctive mitomycin C.

Antibiotics, Antineoplastic↗
PubMed2004

T lymphocyte mediated lysis of mitomycin C treated Tenon's capsule fibroblasts.

AIMS: To evaluate the effect of T cell co-culture on mitomycin C treated and untreated Tenon's capsule fibroblasts. METHODS: IL-2 dependent allogeneic T cells were incubated over a monolayer of mitomycin C treated or control fibroblasts. Fibroblast numbers were evaluated by direct counts using phase contrast microscopy. To determine whether T cell mediated lysis was a consequence of MHC mismatch, co-culture experiments were repeated with autologous T cells. The effect of Fas receptor blockade was established by co-incubation with a Fas blocking (M3) antibody. RESULTS: T cell co-culture resulted in a dramatic reduction in fibroblast survival compared to mitomycin C treatment alone (p = 0.032). T cell killing required fibroblast/lymphocyte cell to cell contact and was observed in both allogeneic and autologous co-culture experiments. Fas blocking antibodies did not significantly inhibit T cell killing (p = 0.39). CONCLUSION: T cells augment mitomycin C treated fibroblast death in vitro. Similar mechanisms may contribute to the cytotoxic effect of mitomycin C in vivo and account for the largely hypocellular drainage blebs that are observed clinically.

Antibiotics, Antineoplastic↗
PubMedDate not supplied

One quadrant sub-Tenon's capsule anesthesia in anterior segment surgery.

Reports of complications associated with local anesthesia in ophthalmic surgery have increased conspicuously in recent years. Sub-Tenon's capsule anesthesia for anterior segment surgery avoids the risks of retrobulbar and peribulbar injections. This study compared sub-Tenon's and retrobulbar anesthesia. Patients undergoing various anterior segment surgery were randomly assigned to sub-Tenon's or retrobulbar anesthesia; 300 were operated with 1-quadrant sub-Tenon's anesthesia (1-QST) and the results were compared with 270 patients operated with retrobulbar anesthesia. Retrobulbar anesthesia consisted of a 2.5 ml injection of a 1:1 mixture of 2% lidocaine without epinephrine and 0.5% bupivacaine. Sub-Tenon's anesthesia involved direct transconjunctival infiltration of the same local anesthetic directly into the sub-Tenon's space, in the inferior-nasal quadrant, using a blunt 23-gauge cannula. Patients undergoing various anterior segment surgery procedures were randomly assigned to 1-QST or retrobulbar anesthesia; 300 patients were operated with 1-QST and the results were compared with 270 patients operated with retrobulbar anesthesia. Preinjection mean (+/- SD) IOP wer 12.9 +/- 3.7 mmHg in the retrobulbar and 13.4 +/- 3.2 mmHg in the 1-QST patients. Preoperative intraocular pressures were 8.7 +/- 3.0 mmHg in the retrobulbar and 9.2 +/- 3.2 mmHg in 1-QST patients. Pre- and postinjection IOP for retrobulbar and 1-QST patients were similar. Pain scores for delivery of the anesthetic, using a numerical rating scale, produced a median score of 1 for 1-QST and 2 for the retrobulbar technique. For the subsequent operative procedure, the median score was 1 for 1-QST and 2 for the retrobulbar patients. Complete akinesia was achieved in 41% with 1-QST and in 69% of retrobulbar patients. 1-QST patients with incomplete akinesia most often had lateral muscle function which did not interfere with the operation. We found the use of a blunt cannula to deliver anesthetic into the sub-Tenon's space as a simple, safe and effective alternative approach to traditional retrobulbar anesthesia in anterior segment surgery.

Anesthesia, Local↗
PubMed1996

Pentoxifylline and pentifylline inhibit proliferation of human Tenon's capsule fibroblasts and production of type-I collagen and laminin in vitro.

After glaucoma filtering surgery, an excessive repopulation of Tenon's capsule fibroblasts (TCFs) with the accumulation of extracellular matrix including collagen types during wound healing may cause scarring of the bleb, resulting in surgical failure. Pentoxifylline (PTX) and pentifylline (PTF), both methylxanthine derivatives, are known to inhibit protein synthesis and proliferation of cells in vitro. We examined the effects of these agents on the proliferation of cultured human TCFs and their production of type-I collagen COOH-terminal peptide (PIP) and laminin to investigate the potential use of the agents as antifibrotic agents after filtering surgery. Both agents inhibited the proliferation of cultured human TCFs and their production of PIP and laminin. The inhibitory effects of PTF on proliferation and production of PIP and laminin were greater than those of PTX. These methylxanthine derivatives may have clinical utility in preventing excessive bleb scarring after glaucoma filtering surgery.

Adult↗
PubMed2000

Tranilast inhibits cell proliferation and collagen synthesis by rabbit corneal and Tenon's capsule fibroblasts.

PURPOSE: To determine whether tranilast, N-(3,4-dimethoxycinnamoyl) anthranilic acid, influences cell proliferation and collagen synthesis by rabbit Tenon's capsule fibroblasts (TFs) and corneal stromal fibroblasts (CFs). METHODS: Rabbit TFs and CFs (7000 cells/well) were cultured in F-12 nutrient mixture supplemented with 1% FBS, plus 0, 3, 30, or 300 microM tranilast, and the number of cells was counted 72 hrs later. To determine the effect of tranilast on collagen synthesis, cells at confluence were cultured in a medium containing 0, 3, 30, or 300 microM tranilast and labeled with 3H-proline, and the amount of radioactivity incorporated into collagenase-sensitive proteins was measured. RESULTS: At 300 microM, tranilast decreased the number of TFs by about 27% and the number of CFs by about 45%, but had no effect on cell viability. The same concentration of tranilast reduced TFs collagen synthesis and CFs collagen synthesis. CONCLUSIONS: Tranilast may inhibit scar formation after trabeculectomy for glaucoma and after excimer laser photorefractive keratectomy.

Animals↗
PubMed2002

Trabeculectomies in fellow eyes have an increased risk of tenon's capsule cysts.

OBJECTIVE: To assess outcomes and complications of primary trabeculectomies in fellow eyes in a large group of patients. The assumption was that first and fellow eyes undergoing fistulizing surgical procedures behave similarly in the postoperative period. DESIGN: Retrospective nonrandomized comparative trial (paired eye study). PARTICIPANTS: Over a 4-year period, 566 consecutive patients underwent primary trabeculectomy, all without antifibrotic agents. One hundred thirty-eight of these patients underwent bilateral surgery. INTERVENTION: A primary trabeculectomy was performed. MAIN OUTCOME MEASURES: Preoperative data, postoperative intraocular pressure, and visual acuity were monitored. In addition, complications and the need for consecutive surgical procedures were noted. RESULTS: The mean follow-up period of these trabeculectomies was 27.4 months (range, 7-62 months). Of the 124 bilateral adult cases, no statistical difference was found in intraocular pressures, number of antiglaucomatous medications, and success or failure rates between the two eyes. The need for enhancement procedures, such as needling or surgical excision of Tenon's capsule cysts, was significantly higher in fellow eyes than in first eyes (16 vs. 6 cases; P = 0.03; Mann-Whitney U test). Hypotony as a complication occurred more frequently in fellow eyes. CONCLUSIONS: Primary trabeculectomies performed in both eyes of patients have a remarkably similar clinical course. Failures of first eyes may be a reason to use antimetabolites in primary trabeculectomy of the fellow eye. The present data suggest that fellow eyes have a greater risk of Tenon's capsule cyst formation. This may be important for patient counseling before surgery. These results may additionally be important for clinical studies. Given that first and fellow eyes do not behave in an absolutely similar manner, study designs making intraindividual comparisons may not be feasible.

Adolescent↗
PubMed1988

The effect of retinoids on the migration of Tenon's capsule fibroblasts.

The effect of the retinoids, retinol and all-trans acid, was assessed in vitro on the migration of rabbit Tenon's capsule fibroblasts, with a view to using these drugs as inhibitors of fibrosis in relation to trabeculectomies. No inhibition of fibroblast migration was demonstrated, and in fact retinol significantly enhanced both the random and directed migration of these cells (p less than 0.001 and p less than 0.01, respectively). This study emphasises the importance of using appropriate cells when investigating the effects of drugs on wound healing.

Animals↗