Hypertensive retinopathy in a transgenic angiotensin-based model

Area of Science:

• Ophthalmology
• Cardiovascular Research
• Genetics

Background:

• Severe hypertension is a known cause of vision loss.
• The renin-angiotensin system (RAS) is implicated in hypertensive damage.
• Understanding the specific retinal mechanisms is crucial for developing treatments.

Purpose of the Study:

• To investigate the role of the renin-angiotensin system (RAS) in hypertensive retinopathy.
• To characterize retinal structural and functional changes in a hypertensive rat model.
• To explore alterations in the outer blood-retinal barrier.

Main Methods:

• Utilized a double-transgenic rat (dTGR) model with elevated angiotensin II (AngII) and Sprague-Dawley (SD) rat controls.
• Performed electroretinography (ERG) to assess retinal function.
• Conducted fluorescence angiography and immunohistology to evaluate retinal vasculature and the blood-retinal barrier.
• Analyzed gene expression of RAS-related and angiogenic factors.

Main Results:

• dTGRs exhibited significantly decreased scotopic a-wave, b-wave, and oscillatory potential amplitudes compared to controls.
• Increased fluorescein leakage from peripheral retinal vessels and structural vascular alterations were observed in dTGRs.
• Ganglion cell degeneration, termed vascular degeneration, was identified.
• Retinal AngII levels were 4-fold higher in dTGRs, with differential expression of RAS and angiogenic genes found.

Conclusions:

• The renin-angiotensin system (RAS) plays a significant role in hypertensive retinopathy, leading to retinal vascular degeneration and functional vision impairment.
• Alterations in the outer blood-retinal barrier are associated with hypertensive retinal disease.
• The established dTGR model serves as a valuable tool for studying hypertensive retinopathy and related visual dysfunction.