PURPOSE: The aim of this study was to examine the localization and the changes in the amount of angiotensin-converting enzyme (ACE) and the relationship between the renin-angiotensin (RA) system and vascular endothelial growth factor (VEGF)/VEGF-receptor system in the retinas of diabetic rats. METHODS: Immunohistochemical localization of ACE, VEGF, and VEGF-receptor fetal liver kinase-1 (Flk-1) was examined in cryosections of the retinas of streptozotocin-injected diabetic rats. A semi-quantitative comparison of diabetic rats with age-matched controls was also performed by counting the ACE- or Flk-1-positive vessels per microscopic field. RESULTS: ACE immunoreactivity was localized in the retinal vessel walls, and the percentages of ACE-positive vessels were significantly increased in the retinas of diabetic rats maintained 3 to 5 months. Both VEGF and Flk-1 signals increased simultaneously with the increment of ACE immunoreactivity. CONCLUSIONS: ACE, expressed in the retinal vessel walls, increases simultaneously with the increment of both VEGF and Flk-1 in the retinas of diabetic rats, suggesting that upregulation of ACE might play some role in the progression of diabetic retinopathy through the VEGF/VEGF receptor system.
PURPOSE: The aim of this study was to examine the localization and the changes in the amount of angiotensin-converting enzyme (ACE) and the relationship between the renin-angiotensin (RA) system and vascular endothelial growth factor (VEGF)/VEGF-receptor system in the retinas of diabeticrats. METHODS: Immunohistochemical localization of ACE, VEGF, and VEGF-receptor fetal liver kinase-1 (Flk-1) was examined in cryosections of the retinas of streptozotocin-injected diabeticrats. A semi-quantitative comparison of diabeticrats with age-matched controls was also performed by counting the ACE- or Flk-1-positive vessels per microscopic field. RESULTS:ACE immunoreactivity was localized in the retinal vessel walls, and the percentages of ACE-positive vessels were significantly increased in the retinas of diabeticrats maintained 3 to 5 months. Both VEGF and Flk-1 signals increased simultaneously with the increment of ACE immunoreactivity. CONCLUSIONS:ACE, expressed in the retinal vessel walls, increases simultaneously with the increment of both VEGF and Flk-1 in the retinas of diabeticrats, suggesting that upregulation of ACE might play some role in the progression of diabetic retinopathy through the VEGF/VEGF receptor system.
Authors: Ik Soo Byon; Dong Hyun Lee; Eun Sook Jun; Min Kyu Shin; Sung Who Park; Ji Eun Lee Journal: Int J Ophthalmol Date: 2017-06-18 Impact factor: 1.779
Authors: H I H El-Sayyad; M A El-Sherbiny; M A Sobh; A M Abou-El-Naga; M A N Ibrahim; S A Mousa Journal: Int J Biol Sci Date: 2011-06-04 Impact factor: 6.580