The effects of age on phosphatic metabolites of the human cornea.
Phosphatic metabolites from human corneas, pooled into 7 decades ranging from ages < 1 year through 79 years, were quantitated using phosphorus-31 magnetic resonance (31P MR) spectroscopy. Relative concentrations of phosphorus-containing compounds measured included the low-energy metabolites [phosphomonoesters (PME), inorganic orthophosphate (Pi), phosphodiesters (glycerol 3-phosphorylethanolamine and glycerol 3-phosphorylcholine)] and the high-energy metabolites [phosphocreatine (PCr), adenosine triphosphate (ATP), adenosine diphosphate (ADP), nucleosidediphosphosugars and the dinucleotides]. Significant linear changes attributable to age occur in the relative mole percentage decrease of phosphate concentrations of human corneal PME, PCr and ATP, and in the increase of Pi. Age-attributable rates of decrease in PME at -0.162 MPP/YR (mole percent phosphorus per year), PCr at -0.015 MPP/YR and ATP at -0.487 MPP/YR combined, approximate the rate of increase in Pi determined to be +0.729 MPP/YR. Of the indices computed from the human corneal spectral data, the ratios of ATP/Pi and PME/Pi and the tissue energy modulus were all found to decrease significantly with age. These changes in corneal phosphatic metabolites are indicative of an overall decline in high-energy metabolism with age.
Lass
J H
JH
Department of Ophthalmology, University Hospitals of Cleveland, Ohio.
Greiner
J V
JV
Merchant
T E
TE
Glonek
T
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D002452:Cell Count; D002648:Child; D002675:Child, Preschool; D003315:Cornea / Q000378:metabolism*; D004728:Endothelium, Corneal / Q000166:cytology; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D010755:Organophosphates / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D010759:Phosphorus Isotopes
D010755:Organophosphates; D010710:Phosphates; D010759:Phosphorus Isotopes