Skin autofluorescence is inversely related to HDL anti-oxidative capacity in type 2 diabetes mellitus.

OBJECTIVE: High density lipoprotein (HDL) particles protect apolipoprotein B-containing lipoproteins from oxidative modification. An impaired anti-oxidative functionality of HDL in type 2 diabetes mellitus (T2DM) may contribute to enhanced formation of oxidative stress products, such as Advanced Glycation Endproducts (AGEs). We tested whether in T2DM the HDL anti-oxidative capacity is related to the accumulation of AGEs in the skin.
METHODS: Skin autofluorescence (AF), a non-invasive read-out for AGEs, and HDL anti-oxidative capacity, i.e. the ability of HDL to protect against LDL oxidation in vitro, were assessed in 67 non-smoking T2DM patients without complications (median age: 60 (53-65), 60% males, 6.5 (5.2-8.5) years of diabetes duration).
RESULTS: In univariate analysis, skin AF correlated inversely with HDL anti-oxidative capacity (r=-0.305, P<0.02), but not with HDL cholesterol or apolipoprotein A-I. HDL anti-oxidative capacity correlated inversely with glucose, HbA(1c), triglycerides, and insulin resistance (homeostasis model assessment) (P<0.05 to P ≤ 0.001). Multiple linear regression showed that skin AF remained inversely related to HDL anti-oxidative capacity (partial r=-0.314, P=0.015) taking account of age, plasma glucose, non-HDL cholesterol, triglycerides, HOMA(ir), and CRP.
CONCLUSION: These findings suggest that skin AF is inversely related to the HDL anti-oxidative capacity rather than to the HDL cholesterol concentration in T2DM. Impaired anti-oxidative functionality of HDL could contribute to tissue accumulation of AGEs.