Hemoglobin autofluorescence as potential long-term glycemic marker in the rat animal model

Diabetes is a serious disease whose patients often require long-term care. Blood glucose and intermediate glycation product of glycated hemoglobin (HbA1c) are, at best, surrogate biomarkers of disease progression. There is indication that advanced glycation end products (AGEs) better reflect diabetic risks. In this study, we explored the use of red blood cells (RBCs) and lysed hemoglobin (Hb) autofluorescence (AF) as potential biomarkers of diabetic complication. AF spectra measured under 370 nm excitation reveals that both RBC and Hb fluorescence in the 420 to 600 nm region. At early time points following diabetic induction in rats, AF increase in lysed Hb is more dramatic compared to that of RBCs. Moreover, we found significance variance of Hb autofluorescence despite relatively constant HbA1c levels. Furthermore, we found that although a correlation exists between AGE autofluorescence and HbA1c levels, the lack of complete correspondence suggests that the rate of AGE production differs significantly among different rats. Our results suggest that with additional development, both RBC and Hb autofluorescence from lysed RBCs may be used act long-term glycemic markers for diabetic complications in patients.