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S. Altimari, T. Mascaro, S. Leopardi, L. Zompatori, A. Missiroli, E. M. Vingolo; Age-Related Correlation Between Ascorbic Acid in Aqueous Humor and Serum. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3952.
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To verify the existence of correlations between ascorbic acid in aqueous humor and serum depending from elderly age.
Seventy patients, 25 males and 45 females, have been examined, with an average age of 69 years, diagnosed corticonuclear cataract, with best visual acuity of 4/10 and a refractive defect between +1.50 and -3.75. Patients underwent aqueous humor sample during phacoemulsification cataract surgery: 0.8 ml of aqueous humor sample were taken by paracentesis of anterior chamber before any surgical procedure, 5ml of blood sample were taken from cubital vein of right arm in the same time. Both after centrifugation a 3000 turns for 10 minutes, underwent assessment of their ascorbic acid concentration by colorimetric method using reactive strips into a reflectometer (RQflex plus). Pearson test (P) and double tail T-Student test for matched data statistical evaluation (significativity level p< 0.05).
The mean ascorbic acid serum concentration was 93.94 mg/l with a standard deviation of 2.54; instead, its aqueous mean concentration was 276.77 and standard deviation was 5.29. Data we obtained allow us to highlight that elderly is related to an increase of ascorbic acid serum concentration and a its decrease in aqueous: in fact, relating ascorbic acid concentrations with age, we obtained a positive correlation in serum (P=0.217; R²=0,0475), while correlation in aqueous resulted negative (P=-0.216; R²=0,0469).
In our opinion data show, as time goes by, there is a reduction of active carriers function, because of their oxidation; therefore, they are not able to permit vitamin C passage from plasma to aqueous any more. According to CHI-HO TO and coll.(3) studies, human mean normal ascorbic acid concentration is about 210mg/l in aqueous with a range between 110 and 320 mg/l, while serum mean concentration is about 80 mg/l and the range is between 60-100mg/l. Therefore, we can assert that change of ascorbic acid levels in the two fluids is mainly due to a same cause, that is damage of active carriers. Then, the lost molecule uptake leads both to ascorbic acid deficit in the eye, and causes an increase in serum of the un-uptaken one. The reduction of concentration in aqueous humor could be explained also by another reason: in fact, it cannot be forgotten that ascorbic acid has a high antioxidizer power and that there is an improvement of free radicals production in cataract pathogenesis. Results we obtained allow us to highlight that ascorbic acid concentration in serum raises with elderly, while the aqueous decreases. Since literature does not provide data from similar studies, comparison is not possible.
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