Endothelin-1 plasma levels and vascular endothelial dysfunction in primary open angle glaucoma

To assess the relationship between endothelial dysfunction, endothelin 1 (ET-1) plasma levels and subclinical inflammation in primary open angle glaucoma (POAG) patients.

We enrolled 40 POAG patients with progressive visual field damage, although well controlled intraocular pressure (IOP) and compared to age and sex matched healthxy subjects. Each patient underwent an ophthalmological examination, a standard achromatic perimetry (SAP), blood sampling to assess ET-1 plasma levels, an objective assessment of cellularity within the anterior chamber (FLARE) and measurement of flow mediated dilation (FMD) with high resolution 2-dimensional ultrasonographic imaging of the brachial artery.

At baseline, POAG patients, compared to healthy controls, showed an increase of ET-1 plasma levels: 2.83 ± 0.28 pg/ml vs. 1.75 ± 0.25 pg/ml (p<0.001), lower FMD values 4.46 ± 1.28% vs. 13.18 ± 2.80% (p<0.001) and increased FLARE values 9.98 ± 0.97 photons/ms vs. 5.87 ± 0.64 photons/ms (p<0.001). A follow up after 1 year revealed a further increase of ET-1 plasma levels (to 3.68 ± 0.60; p<0.001) and decrease of FMD (3.52 ± 1.28; p>0.001).

The increase of ET-1 in POAG patients is related to vascular dysfunction (r=0.942; p=0.001) and vascular dysfunction is related to sub-clinical intraocular inflammation (r=0.968; p=0.001). Thus ET-1 and vascular dysfunction related to sub-clinical inflammation may play a key role in determining a progressive visual field damage in POAG patients who present a well-controlled IOP.