Effect of antihypertensive treatment on blood-retinal barrier permeability to fluorescein in hypertensive Type 1 (insulin-dependent) diabetic patients with background retinopathy

Summary The effect of antihypertensive treatment on blood-retinal barrier leakage of fluorescein in background retinopathy was studied in nine hypertensive Type 1 (insulin-dependent) diabetic patients suffering from nephropathy. The patients were investigated before and after 7 (3 to 13) months of treatment with captopril (n=8; 25 to 100 mg daily) and a diuretic, either frusemide (n=4; 80 to 200 mg daily) or bendrofluazide (n=2; 2.5 mg daily). Retinal function was assessed by fundus photography, fluorescein angiography, vitreous fluorometry, and renal function by glomerular filtration rate, and albuminuria. The antihypertensive treatment induced a significant reduction (p<0.05) in: blood pressure from 152/97±14/8 mmHg to 134/82±11/6 mmHg; blood-retinal barrier leakage of fluorescein from 2.4 ±1.1 to 1.4±0.5·10^–7 cm/second; albuminuria from 1391 (range: 168–4852) g/min to 793 (range: 35–2081) ug/min. Glomerular filtration rate declined from 88±15 to 78±23 ml·min^–1·1.73 m² (0.05<p<0.10). The metabolic control of the patients as reflected by their blood glucose and HbA_1c levels remained stable during the study. Our study suggests that systemic blood pressure elevation contributes to the abnormal blood-retinal barrier permeability to fluorescein characteristically found in diabetic background retinopathy and that this abnormality can be reversed during antihypertensive treatment.