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Paclitaxel inhibits growth, migration and collagen production of human Tenon's fibroblasts--potential use in drug-eluting glaucoma drainage devices.

Choritz L, Grub J, Wegner M, Pfeiffer N, Thieme H - Graefes Arch. Clin. Exp. Ophthalmol. (2009)

Bottom Line: However, no statistically significant difference was observed between any of the concentrations, indicating that this inhibition may be an indirect effect.Paclitaxel may be a useful addition to the repertoire of anti-proliferative substances currently in use in glaucoma filtering surgery and shunt implantation.Further studies of the compound and its effects on Tenon's fibroblasts as well as other ocular tissues are warranted.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.

ABSTRACT

Objective/aim: One of the factors limiting the long-term success of glaucoma drainage devices and traditional filtering surgery is the tendency of bleb encapsulation. Glaucoma shunts present an opportunity of introducing drug-eluting mechanisms for a lasting exposure of the bleb to anti-proliferative substances. The aim of this in vitro study was to investigate the effects of short- and long-term exposure of primary cultures of human Tenon's fibroblasts to different concentrations of paclitaxel on cell proliferation, migration, collagen production and cytotoxicity, in order to evaluate the suitability of the drug for the use in such a device.

Materials/methods: Seven individual primary cultures of human Tenon's fibroblasts were observed over the course of 1 week after administering paclitaxel concentrations varying from 10(-9) mol/l to 10(-6) mol/l for either 1 hour or continuously. Relative cell count and migration across a cell-free area introduced by scratching through a confluent cell layer were determined every 24 hours, using photomicrographs of the cells for each concentration and exposure time. Soluble collagen concentration in the cell culture medium was determined using a Sircol collagen assay 72 hours after paclitaxel exposure. Cytotoxicity of the compound was assessed by flow cytometry using dual staining with annexin V-FITC and propidium iodide.

Results: Paclitaxel dose-dependently inhibited both proliferation and migration of the cells. Cell count was reduced at all concentrations and both exposure times (p = 0.001); similarly, all but two concentrations of paclitaxel caused a significant reduction of cell migration (p < 0.001). This may be explained in part by the dose- and time-dependent induction of apoptosis in up to 23.7% of the cells (maximal effect at 10(-6) mol/l, 7 days after exposure). Collagen production was significantly reduced at all concentrations and at both exposure times. However, no statistically significant difference was observed between any of the concentrations, indicating that this inhibition may be an indirect effect.

Conclusion: Paclitaxel may be a useful addition to the repertoire of anti-proliferative substances currently in use in glaucoma filtering surgery and shunt implantation. Further studies of the compound and its effects on Tenon's fibroblasts as well as other ocular tissues are warranted.

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Related in: MedlinePlus

Rates of apoptosis (a, b) and necrosis (c, d) after brief (a, c) or extended (b, d) exposure to paclitaxel at 1, 4 and 7 days after treatment
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Fig7: Rates of apoptosis (a, b) and necrosis (c, d) after brief (a, c) or extended (b, d) exposure to paclitaxel at 1, 4 and 7 days after treatment

Mentions: The mean rate of apoptosis increased in a dose- and time-dependent fashion to 22.5 ± 8.1% on day 7 for cells exposed to 10−6 mol/l of paclitaxel for 1 hour. Rate of apoptosis was 14.1 ± 4.1%, 3.8 ± 0.9%, and 3.5 ± 1.1% for 10−7 mol/l, 10−8 mol/l and 10−9 mol/l respectively. Continuous exposure to paclitaxel led to apoptosis rates of 23.7 ± 7.2%, 17.3 ± 7.9%, 9.9 ± 3.0%, and 2.4 ± 1.0% for 10−6 mol/l, 10−7 mol/l, 10−8 mol/l and 10−9 mol/l. (Fig. 7a,b). The rate of necrotic cells remained very low and relatively stable over the entire observation period. It was highest in the samples continuously exposed to higher concentration of paclitaxel (Fig. 7c,d). Because of large variability between individual cell lines, and because only three of the seven cell lines were used for this assay, the apparent differences between the treatment concentrations did not reach global statistical significance.Fig. 7


Paclitaxel inhibits growth, migration and collagen production of human Tenon's fibroblasts--potential use in drug-eluting glaucoma drainage devices.

Choritz L, Grub J, Wegner M, Pfeiffer N, Thieme H - Graefes Arch. Clin. Exp. Ophthalmol. (2009)

Rates of apoptosis (a, b) and necrosis (c, d) after brief (a, c) or extended (b, d) exposure to paclitaxel at 1, 4 and 7 days after treatment
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2801844&req=5

Fig7: Rates of apoptosis (a, b) and necrosis (c, d) after brief (a, c) or extended (b, d) exposure to paclitaxel at 1, 4 and 7 days after treatment
Mentions: The mean rate of apoptosis increased in a dose- and time-dependent fashion to 22.5 ± 8.1% on day 7 for cells exposed to 10−6 mol/l of paclitaxel for 1 hour. Rate of apoptosis was 14.1 ± 4.1%, 3.8 ± 0.9%, and 3.5 ± 1.1% for 10−7 mol/l, 10−8 mol/l and 10−9 mol/l respectively. Continuous exposure to paclitaxel led to apoptosis rates of 23.7 ± 7.2%, 17.3 ± 7.9%, 9.9 ± 3.0%, and 2.4 ± 1.0% for 10−6 mol/l, 10−7 mol/l, 10−8 mol/l and 10−9 mol/l. (Fig. 7a,b). The rate of necrotic cells remained very low and relatively stable over the entire observation period. It was highest in the samples continuously exposed to higher concentration of paclitaxel (Fig. 7c,d). Because of large variability between individual cell lines, and because only three of the seven cell lines were used for this assay, the apparent differences between the treatment concentrations did not reach global statistical significance.Fig. 7

Bottom Line: However, no statistically significant difference was observed between any of the concentrations, indicating that this inhibition may be an indirect effect.Paclitaxel may be a useful addition to the repertoire of anti-proliferative substances currently in use in glaucoma filtering surgery and shunt implantation.Further studies of the compound and its effects on Tenon's fibroblasts as well as other ocular tissues are warranted.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.

ABSTRACT

Objective/aim: One of the factors limiting the long-term success of glaucoma drainage devices and traditional filtering surgery is the tendency of bleb encapsulation. Glaucoma shunts present an opportunity of introducing drug-eluting mechanisms for a lasting exposure of the bleb to anti-proliferative substances. The aim of this in vitro study was to investigate the effects of short- and long-term exposure of primary cultures of human Tenon's fibroblasts to different concentrations of paclitaxel on cell proliferation, migration, collagen production and cytotoxicity, in order to evaluate the suitability of the drug for the use in such a device.

Materials/methods: Seven individual primary cultures of human Tenon's fibroblasts were observed over the course of 1 week after administering paclitaxel concentrations varying from 10(-9) mol/l to 10(-6) mol/l for either 1 hour or continuously. Relative cell count and migration across a cell-free area introduced by scratching through a confluent cell layer were determined every 24 hours, using photomicrographs of the cells for each concentration and exposure time. Soluble collagen concentration in the cell culture medium was determined using a Sircol collagen assay 72 hours after paclitaxel exposure. Cytotoxicity of the compound was assessed by flow cytometry using dual staining with annexin V-FITC and propidium iodide.

Results: Paclitaxel dose-dependently inhibited both proliferation and migration of the cells. Cell count was reduced at all concentrations and both exposure times (p = 0.001); similarly, all but two concentrations of paclitaxel caused a significant reduction of cell migration (p < 0.001). This may be explained in part by the dose- and time-dependent induction of apoptosis in up to 23.7% of the cells (maximal effect at 10(-6) mol/l, 7 days after exposure). Collagen production was significantly reduced at all concentrations and at both exposure times. However, no statistically significant difference was observed between any of the concentrations, indicating that this inhibition may be an indirect effect.

Conclusion: Paclitaxel may be a useful addition to the repertoire of anti-proliferative substances currently in use in glaucoma filtering surgery and shunt implantation. Further studies of the compound and its effects on Tenon's fibroblasts as well as other ocular tissues are warranted.

Show MeSH
Related in: MedlinePlus