Apolipoprotein A-I concentration in tears in diabetic retinopathy

Background Apolipoprotein concentrations in re eex tears from healthy and noninsulin-dependent diabetes mellitus (NIDDM) subjects were measured and correlated with the stage of diabetic retinopathy. Methods and results The apolipoprotein A-I (apo A-I) concentrations in the tears from NIDDM patients with retinopathy were signiecantly higher than those from patients with no or negligible retinopathy ( P50¢05), and apo A-I was not detected in healthy subjects by Western blotting. No reactive band was detected on apo A-I by Western blotting for nitrotyrosine, a marker for peroxynitrite oxidation of the tear proteins. Apo A-I concentration in tears was signiecantly correlated with the stage of retinopathy ( r ˆ 0¢598, n ˆ 59, P50¢001). No apo A-I gene expression was detected in the conjunctiva by reverse transcription polymerase chain reaction. Conclusions We conclude that there is increased secretion of native apo A-I from the main lacrimal gland in patients with advanced diabetic retinopathy. Ann Clin Biochem 2002; 39: 56-61