Elevated aqueous endothelin-1 concentrations in advanced diabetic retinopathy

Area of Science:

• Ophthalmology
• Vascular Biology
• Endocrinology

Background:

• Endothelin-1 (ET-1) is a potent vasoconstrictor implicated in diabetic retinopathy (DR) pathogenesis.
• Limited studies have investigated intraocular ET-1 levels in DR patients.

Purpose of the Study:

• To investigate aqueous humor ET-1 levels in patients with DR.
• To compare ET-1 levels between different stages of DR and control subjects.
• To assess the effect of intravitreal bevacizumab (IVB) on aqueous ET-1 levels in DR patients.

Main Methods:

• Prospective study including 85 subjects: advanced DR (n=40), early DR (n=19), and control (n=26).
• Aqueous humor ET-1 levels were measured before and 1 month after IVB in DR patients, and at cataract surgery in controls.
• DR was classified into mild/moderate nonproliferative DR (early) and severe nonproliferative/proliferative DR (advanced).

Main Results:

• Mean aqueous ET-1 levels were significantly higher in advanced DR (10.1 pg/mL) compared to early DR (1.9 pg/mL) and controls (2.1 pg/mL) (P < 0.001).
• No significant difference in ET-1 levels was observed between severe nonproliferative DR and proliferative DR at baseline.
• Following IVB, mean aqueous ET-1 levels significantly decreased in both severe nonproliferative DR (2.5 pg/mL) and proliferative DR (2.9 pg/mL) groups (P < 0.001).

Conclusions:

• Elevated aqueous ET-1 levels are associated with advanced diabetic retinopathy.
• Intravitreal bevacizumab treatment effectively reduces ET-1 levels in DR patients.
• Further research into ET-1's role in DR pathogenesis and potential therapeutic interventions is warranted.