Effects of angiotensin II type 1-receptor blockade on retinal endothelial function.

What Was Tested

This randomized controlled trial looks at Angiotensin II Type 1 Receptor Blockers.

Hypercholesterolemia is an important risk factor for atherosclerotic vascular disease including stroke.

Low-density lipoprotein-cholesterol may induce upregulation of angiotensin II type 1 (AT1)-receptors and their activation plays a pathogenetic role in atherosclerosis, possibly via enhanced breakdown of nitric oxide.

Who Took Part

According to the abstract, 17 subjects were involved.

PubMed indexes the participants as adults and middle-aged adults, both men and women.

Thirty-one hypercholesterolemic and 17 normocholesterolemic subjects were randomly assigned to treatment with irbesartan and placebo in a double-blind crossover study.

How the Study Was Run

The researchers set it up as a randomized, double-blind, placebo-controlled and crossover study.

Random assignment meant chance, not the researchers, decided who got Angiotensin II Type 1 Receptor Blockers and who got the comparison, which limits bias.

Blinding on both sides kept the subjects and researchers unaware of who received Angiotensin II Type 1 Receptor Blockers.

The comparison arm used a placebo, so changes seen with Angiotensin II Type 1 Receptor Blockers could be set against what happens without it.

Each person switched between Angiotensin II Type 1 Receptor Blockers and the comparison at some point, usually with a gap in between.

Retinal capillary flow was measured using scanning laser Doppler flowmetry.

Diffuse luminance flicker was applied to provoke vasodilation that is in part nitric oxide dependent.

What Was Measured

Topics PubMed links to this paper include Angiotensin II Type 1 Receptor Blockers, Biphenyl Compounds, Endothelium, Vascular, Hypercholesterolemia, Irbesartan, Laser-Doppler Flowmetry and Regional Blood Flow.

What This Means in Plain Language

The paper is a randomized, double-blind and placebo-controlled study of Angiotensin II Type 1 Receptor Blockers in 17 subjects.

With fewer than 40 people, it is a small study, so it is better read as an early signal for further research than as a settled answer.

The abstract goes on to report its results in about 5 sentences; this page does not restate them, so read the paper for the findings and their limits.

The publication is from 2008 (Journal of hypertension), a journal based in Netherlands.

More context: all human trials.