VITAMIN C FUNCTIONS IN THE CORNEA: ULTRA-STRUCTURAL FEATURES IN ASCORBATE DEFICIENCY

SERRA HM; SUAREZ MARÍA F; ESPOSITO E; URRETS-ZAVALIA JA; PREEDY V

Handbook of diet, nutrition and the eye

ELSEVIER SCIENCE INC

Año: 2014;

The cornea plays important roles in the eye, since it maintains the ocular pressure, bears up different aggressions and forces and it constitutes the primary lens in many animals? eyes. In order to fulfill these extremely crucial functions, the cornea requires sophisticated structures called epithelium, Bowman?s membrane, stroma, Descement?s layer and endothelium. The complexity of this tissue is such that despite many efforts, it has not been possible to obtain clinically viable corneas in the lab yet. Vitamin C or L-ascorbic acid is an essential vitamin and a water-soluble important nutrient, which many animals chemically synthesize from the glucose by means of enzymatic reactions, being the L-gulono γ - lactone oxidase the last enzyme. Among the multiple roles played by this vitamin, its primary functions are to act as a co-factor for reactions requiring a reduced iron or copper metalloenzyme and as a protective antioxidant that operates in the aqueous phases, both intra and extra-cellularly. Ocular tissues, particularly the cornea, concentrate vitamin C, which might suggest that the different structures of the cornea need this vitamin to fulfill their roles. In this work we present scientific evidences of ascorbic acid critical roles in maintaining the functions and ultra-structures of the corneal epithelium, the stroma and the endothelium.