The retinal tolerance to bevacizumab in co-application with a recombinant tissue plasminogen activator
- Matthias Lüke1,
- Kai Januschowski1,
- Max Warga1,
- Julia Beutel1,
- Martin Leitritz1,
- Faik Gelisken1,
- Salvatore Grisanti1,
- Toni Schneider2,
- Christoph Lüke3,
- Karl Ulrich Bartz-Schmidt1,
- Peter Szurman1,
- for the Tuebingen Bevacizumab Study Group
- 1University Eye Hospital, Centre for Ophthalmology, Eberhard-Karls University of Tuebingen, Tuebingen, Germany
- 2Institute for Neurophysiology, University of Cologne, Köln, Germany
- 3Center of Ophthalmology, University of Cologne, Köln, Germany
- Correspondence to: Dr. M Lüke Department of Ophthalmology, University of Tuebingen, Schleichstr. 12–16, D-72076, Tuebingen, Germany; matthias.lueke{at}med.uni-tuebingen.de
- Accepted 4 March 2007
- Published Online First 23 March 2007
Abstract
Aim: To investigate the retinal toxicity of bevacizumab in co-application with a commercially available recombinant tissue plasminogen activator (rt-PA), and to facilitate a new therapeutic concept in the treatment of massive subretinal haemorrhage caused by neovascular age-related macular degeneration (AMD).
Methods: Isolated bovine retinas were perfused with an oxygen-preincubated nutrient solution. The electroretinogram (ERG) was recorded as a transretinal potential using Ag/AgCl electrodes. Bevacizumab (0.25 mg/ml) and rt-PA (20 μg/ml) were added to the nutrient solution for 45 min. Thereafter, the retina was reperfused for 60 min with normal nutrient solution. Similarly, the effects of rt-PA (20 μg/ml, 60 μg/ml and 200 μg/ml) on the a- and b-wave amplitudes were investigated. The percentages of a- and b-wave reduction during application and at washout were calculated.
Results: During application of bevacizumab (0.25 mg/ml) in co-application with 20 μg/ml (rt-PA), the ERG amplitudes remained stable. The concentrations of rt-PA alone (20 μg/ml and 60 μg/ml) did not induce significant reduction of the b-wave amplitude. In addition, 20 μg/ml rt-PA did not alter the a-wave amplitude. However, 60 μg/ml rt-PA caused a slight but significant reduction of the a-wave amplitude. A full recovery was detected for both concentrations during the washout. At the highest tested concentration of 200 μg/ml rt-PA, a significant reduction of the a- and b-wave amplitudes was provoked during the exposure. The reduction of ERG amplitudes remained irreversible during the washout.
Conclusion: The present study suggests that a subretinal injection of 20 µg/ml rt-PA in co-application with bevacizumab (0.25 mg/ml) for the treatment of massive subretinal haemorrhage seems possible. This is a safety study. Therefore, we did not test the clinical effectiveness of this combined treatment.
- AMD, age-related macular degeneration
- CNV, choroidal neovascularization
- ERG, electroretinogram
- rt-PA, recombinant tissue plasminogen activator
- VEGF, vascular endothelial growth factor
- age-related macular degeneration
- bevacizumab
- recombinant tissue plasminogen activator
- electroretinogram
- retinal toxicity
- AMD, age-related macular degeneration
- CNV, choroidal neovascularization
- ERG, electroretinogram
- rt-PA, recombinant tissue plasminogen activator
- VEGF, vascular endothelial growth factor
- age-related macular degeneration
- bevacizumab
- recombinant tissue plasminogen activator
- electroretinogram
- retinal toxicity
Footnotes
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Published Online First 23 March 2007
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Competing interests: None declared.







