Effect of intermediate aldehydes on CMA formation. (a) Dose-dependent effect of glucose on CMA formation in glycated collagen. Type I collagen (1.5 mg/mL) was incubated with the indicated concentration of glucose at 37°C for 4 weeks. Aminoguanidine (AG), pyridoxamine (PM), and diethylenetriaminepentaacetic acid (DTPA) (1 mM each) were added before glucose addition. (b) CMA formation of aldehyde-modified collagen and HSA. Glyoxal- (GO-), methylglyoxal- (MG-), and glycolaldehyde- (GA-) modified collagen and HSA were prepared by incubation with 1 mM of these aldehydes for up to 7 days, and 3-deoxyglucosone- (3DG-) modified collagen and HSA were also prepared by incubation with 30 mM 3DG for up to 28 days. (c) Dose-dependent effect of glyoxal on CMA and CML formation in collagen. Type I collagen and HSA (1.5 mg/mL each) were incubated with the indicated concentrations of glyoxal at 37°C for 7 days, and CMA and CML contents were determined by ELISA.