ROCK Inhibition by Fasudil Ameliorates Diabetes-Induced Microvascular Damage
- Ryoichi Arita1,
- Yasuaki Hata (hatachan{at}med.kyushu-u.ac.jp)1,
- Shintaro Nakao1,2,
- Takeshi Kita1,
- Muneki Miura1,
- Shuhei Kawahara1,
- Souska Zandi2,
- Lama Almulki2,
- Faryan Tayyari2,
- Hiroaki Shimokawa3,
- Ali Hafezi-Moghadam2 and
- Tatsuro Ishibashi1
- 1 Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan
- 2 Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 325 Cambridge Street, 3rd Floor Boston, MA 02114, USA
- 3 Department of Cardiology, Graduate School of Medicine, Tohoku University, 1-1 Seiryo-Machi, Aoba-Ku, Sendai 980-8575 Japan
Abstract
OBJECTIVE: Leukocyte adhesion in retinal microvasuculature substantially contributes to diabetic retinopathy (DR). Involvement of the Rho/ROCK pathway in diabetic microvasculopathy and therapeutic potential of fasudil, a selective ROCK inhibitor, are investigated.
RESEARCH DESIGN AND METHODS: Localization of RhoA/ROCK and Rho activity were examined in rats' retinal tissues. Impact of intravitreal fasudil administration on retinal eNOS and MYPT-1 phosphorylation, ICAM-1 expression, leukocyte adhesion, and endothelial damage in rat eyes were investigated. Adhesion of neutrophils from DR patients or non-diabetic control subjects to cultured microvascular endothelial cells was quantified. Fasudil's potential for endothelial protection was investigated by measuring the number of adherent neutrophils and TUNEL-positive endothelial cells.
RESULTS: RhoA and ROCK co-localized predominantly in retinal micro-vessels. Significant Rho activation was observed in retinas of diabetic rats. Intravitreal fasudil significantly increased eNOS phosphorylation, while it reduced MYPT-1 phosphorylation, ICAM-1 expression, leukocyte adhesion, and the number of damaged endothelium in retinas of diabetic rats. Neutrophils from DR patients showed significantly higher adhesion to cultured endothelium and caused endothelial apoptosis, which was significantly reduced by fasudil. Blockade of the Fas-FasL interaction prevented endothelial apoptosis. The protective effect of fasudil on endothelial apoptosis was significantly reversed by L-NAME, a NOS inhibitor, while neutrophil adhesion remained unaffected.
CONCLUSION: The Rho/ROCK pathway plays a critical role in diabetic retinal microvasculopathy. Fasudil protects the vascular endothelium by inhibiting neutrophil adhesion and reducing neutrophil-induced endothelial injury. ROCK inhibition may become a new strategy in the management of DR, especially in its early stages.
Footnotes
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- Received June 9, 2008.
- Accepted September 25, 2008.
- Copyright © American Diabetes Association
