Human crystalline lens phospholipid analysis with age

Paired human crystalline lenses (n = 21, patient ages 20-79 years) were extracted for lipids with chloroform-methanol 2:1, using the Folch method. The extracted crude lipids were analyzed at 202.4 MHz by phosphorus-31 magnetic resonance spectroscopy (31P NMR). Fourteen membrane phospholipids were detected including phosphatidylcholine (PC), lysophosphatidylcholine (LPC), phosphatidylcholine plasmalogen (PC plas), phosphatidylethanolamine (PE), phosphatidylethanolamine plasmalogen, lysophosphatidylethanolamine (PA), phosphatidylglycerol (PG), lysophosphatidylglycerol, phosphatidylserine (PS), phosphatidic acid, phosphatidylinositol, sphingomyelin (SPH), and two uncharacterized phospholipids. The uncharacterized phospholipid at 0.13 was the predominant phospholipid, comprising 43.20% of the lens phospholipid profile. A decrease in mole percent of phosphorus concentrations of PE, PC plas, and PC and an increase in SPH correlated with age. The following computed indices decreased with age: PC/PG and PE/PS; PC + PE; (PC + PC plas); and PC/PS. The following computed indices increased with age: (PC + SPH)/(PE + PS), SPH/PG, (PC + SPH)/(PE + PS), LPC/PC, LPE/PE, SPH/PE, and SPH/PC. Changes in membrane phospholipids of the crystalline lens with age as detected by 31P NMR can be used to fingerprint lens maturation.