Abstract
Purpose :
To study the levels of melatonin in the aqueous humour of normotensive and hypertensive IOP patients and to compare them in an animal model of glaucoma.
Methods :
37 eyes of 37 patients who underwent cataract surgery were included in the study and were divided into normotensive patients, with IOP below 21 mmHg (n=23) and hypertensive patients, with IOP > 21 mm Hg (n=14). Glaucomatous DBA/2J (n=6) and control C57BL/6J (n=6) mice presenting 3 and 15 months of age for each strain were also used. Human and mice aqueous humours were aspirated using a 30-gauge Rycrof cannula on a tuberculin syringe and further processed to quantify melatonin by HPLC analysis.
Results :
Melatonin levels in normotensive patients (IOP below 21 mm Hg) presented values of 33.14 ± 11.61 ng/mL (n=23), while hypertensive patients (IOP above 21 mm Hg) showed melatonin concentrations of 95.87 ± 28.23 ng/mL (n=14) (p<0.039). Glaucoma mice presented melatonin values of 0.44 ± 0.06 ng/mL (at 3 months of age, before the pathology starts) which raised to 1.45 ± 0.18 ng/mL (at 15 months of age, when the pathology is fully established and IOP is maximum) (n= 6, p<0.001). Control mice did not significantly modified melatonin concentrations between 3 and 15 months of age.
Conclusions :
Glaucoma patients with high IOP present increased concentrations of melatonin in their aqueous humour compared to normotensive patients. This has been confirmed in a glaucomatous animal model in which it has been possible to see a correlation between the development of the pathology, with an increase in IOP, and a concomitant elevation of melatonin in the aqueous humour.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.