Phosphatic metabolism and corneal edema.

From three groups of patients with corneal edema, the degree of edema was clinically quantified prior to penetrating keratoplasty. Corneas from patients with failed grafts (n = 16) had the greatest edema (mean score 3.8 +/- 0.6 SE), corneas with Fuchs' endothelial dystrophy (n = 12) had the least edema (1.4 +/- 0.4), and corneas with aphakic and pseudophakic bullous keratopathy (n = 40) had intermediate edema (2.7 +/- 0.5). Phosphorus-31 nuclear magnetic resonance spectroscopy was used to quantitate five high-energy phosphates and nine low-energy phosphates and calculate 12 metabolic indices from the specimens of these three edematous groups. Corneas with aphakic and pseudophakic bullous keratopathy had lower alpha-glycerophosphate (alpha-GP) and glycerol 3-phosphorylethanolamine and glycerol 3-phosphorylcholine (GPE & GPC), and higher phosphocreatine (PCr), adenosine diphosphate (ADP), monoesters/diesters, PCr/Pi (phosphocreatine/inorganic orthophosphate), and PCr/ATP (phosphocreatine/adenosine triphosphate) than corneas with Fuchs' endothelial dystrophy (p less than 0.05). Corneas from failed grafts had lower alpha-GP, ethanolamine phosphate (EP), ethanolamine phosphate and choline phosphate (EP&CP), monoesters/Pi, ATP/Pi, and energy modulus, no detectable GPE and GPC, and higher Pi, phosphorylglycans (PG), PCr, ADP, diesters, PCr/Pi, and PCr/ATP than those with Fuchs' endothelial dystrophy (p less than 0.05). Corneas from failed grafts had lower ATP, monoesters/Pi, ATP/Pi, PCr/Pi, and energy modulus and higher Pi, PG, ADP, diesters, and PCr/ATP than corneas with aphakic and pseudophakic bullous keratopathy (p less than 0.05). In summary, there was increasing decline in the high-energy metabolites and energy status with increasing edema.