Measurement of serum AGEs was modified from Kaluousava et al.11 Serum was diluted 1:20 to 1:10 with phosphate buffer saline (PBS) pH 7.4 (Sigma). AGEs fluorescence intensity was measured at 350/440 (Ex/Em) nm with a spectrofluorometer (Shimadzu Model RF-1501, Shimadzu). Serum total protein (TP) was measured by Biuret method (Dimension RXL, Dade Behring). Serum AGEs was expressed as a ratio of AGEs fluorescence intensity to total protein (AGEs/TP ratio). All analyses were performed in triplicates.