Phosphatic intermediate metabolites of the porcine ocular tunica fibrosa

This study compares porcine scleral and corneal phosphorylated intermediate metabolites determined using 31P NMR. These tissues comprise the tunica fibrosa (outer coat) of the eye. Since the sclera does not possess epithelia as does the cornea, comparative analysis of these tissues included examination of the cornea with and without its epithelia. The phosphorylated intermediates detected include: dihydroxyacetone phosphate, hexose 6-phosphates, alpha-glycerol phosphate, beta-glycerol phosphate, ethanolamine and choline phosphates, nucleoside mono-, di-, and tri-phosphates, inorganic orthophosphate, glycerol 3-phosphoryl-ethanolamine and -choline, phosphoglycans, phosphocreatine, nucleoside diphosphosugars, dinucleotides, and four uncharacterized (unknown) signals. Metabolic indices, comprised of individual or grouped metabolites, were calculated to further compare and contrast metabolites and to provide more pathway specific metabolic interrelations for phosphorylated metabolites. Significant differences exist between the corneal stroma and the sclera in 16 of the 22 phosphorylated metabolites determined, whereas differences exist between the whole cornea and the sclera in six of the 22 phosphorylated metabolites. Considering all metabolite levels and metabolic indices in aggregate, the sclera is most similar to the whole cornea and least similar to the corneal stroma.