title: Suppressed endothelin-1 by anti-VEGF therapy is important for patients with BRVO-related macular edema to improve their vision.
abstract: BACKGROUND
  Branch retinal vein occlusion (BRVO) commonly occurs at the arteriovenous crossing in the unilateral eye, and cardiovascular diseases can be risk factors of BRVO. However, the pathomechanism leading to BRVO is not yet clear. In addition to mechanical compression, the vein might locally constrict due to an altered biochemical environment, such as an increase in the concentration of endothelin-1 (ET-1). We evaluated changes in ET-1 following injection of intravitreal bevacizumab (IVB), which is the anti-vascular endothelial growth factor (VEGF) agent with the longest serum half-life, to determine the effect on BRVO-related macular edema.
  
  
  METHODS
  Twenty consecutive patients with BRVO-related macular edema (10 males, 10 females; age range 56-83 years) who visited our hospital were included in this prospective study. Visual acuity (VA); central retinal thickness (CRT), determined by macular optical coherence tomography (OCT); and plasma ET-1 levels were obtained before IVB treatment and 1 month later.
  
  
  RESULTS
  Patients had hypertension (80 %), dyslipidemia (50 %), diabetes mellitus (35 %), or collagen disease (5 %). Mean CRT was significantly decreased from 673.0 ± 327.8 to 388.2 ± 155.0 μm (P = 0.0007), and mean VA was significantly improved after IVB (P = 0.0239). Mean plasma ET-1 was significantly decreased from 1.272 ± 0.451 to 1.095 ± 0.316 pg/mL (P = 0.0238); however, the plasma ET-1 level was increased in all five patients who did not show improved VA after IVB.
  
  
  CONCLUSIONS
  In patients with BRVO-related macular edema, anti-VEGF therapy leads to an expected reduction in ET-1 levels; however, the ET-1 level was found to increase in some patients; this is clearly related to less improvement of VA after anti-VEGF therapy.
  
  
  BACKGROUND
  University hospital Medical Information Network (UMIN) Center UMIN000013236. Registered 10 October, 2012.
authors: Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka 569-8686 Japan.
authors: Teruyo
authors: T
authors: Kida
authors: Department of Ophthalmology, University of Basel, Basel, Switzerland.
authors: Josef
authors: J
authors: Flammer
authors: Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka 569-8686 Japan.
authors: Hidehiro
authors: H
authors: Oku
authors: Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka 569-8686 Japan.
authors: Seita
authors: S
authors: Morishita
authors: Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka 569-8686 Japan.
authors: Masanori
authors: M
authors: Fukumoto
authors: Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka 569-8686 Japan.
authors: Hiroyuki
authors: H
authors: Suzuki
authors: Department of Ophthalmology, University of Basel, Basel, Switzerland.
authors: Katarzyna
authors: K
authors: Konieczka
authors: Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka 569-8686 Japan.
authors: Tsunehiko
authors: T
authors: Ikeda
keywords: Anti-VEGF; Branch retinal vein occlusion (BRVO); Endothelin-1; Macular edema