Roles of Klotho and Endothelin-1 in pseudoexfoliation
Serum and aqueous levels of Klotho levels are reduced in pseudoexfoliation syndrome (PXF) and pseudoexfoliative glaucoma (PEG) while Endothelin-1 (ET-1) is increased, researchers say.
“These findings support the hypothesis that Klotho deficiency may play an important role in the occurrence and severity of [PXF] and even its progression to PEG, caused, at least in part by the accelerating aging process,” Mohammad H. Ahoor and colleagues from Tabriz University of Medical Science in Tabriz, Iran report in the Journal of Glaucoma.
Discovered in 1997, Klotho plays an important role in the health of endothelial cells. Levels of Klotho correlate with age, and PXF and PEG are both age-related diseases. Klotho has been associated with age-related kidney damage and, in animal models, with diabetes and hypertension.
Meanwhile, ET-1 acts as a vasoconstrictor in the regulation of ocular blood flow and the trabecular network contraction to control IOP, as well as contracting the ciliary muscle.
Given the role of impaired endothelial cell function and oxidative stress in the pathogenesis of PXF, Ahoor and colleagues hypothesized that low serum and aqueous humor Klotho and high serum and aqueous humor ET-1 levels might be found in PXF or PEG.
A common age-related fibrillopathy, PXF is the most common clinical precursor of open-angle glaucoma. Recent research has implicated impaired function of endothelial cells and oxidative stress in its pathogenesis.
To investigate, the researchers recruited 45 patients with senile cataract, of whom 15 had PXF, 15 had PEG, and 15 served as controls. The patients ranged from 40 to 70 years of age.
Patients were excluded if they had a best-corrected visual acuity of less than 20/80, an IOP greater than 21 mm Hg with or without drug treatment, a history of ocular surgery, or several other categories of eye disease and systemic illness.