Partial characterization of the molecular nature of collagen-linked fluorescence: Role of diabetes and end-stage renal disease

Collagen-linked fluorescence at excitation/emission 370/440 nm has widely been used as a marker for advanced glycation in studies of aging, diabetic complications, and end-stage renal disease (ESRD). Diagnostic devices measuring skin autofluorescence at this wavelength revealed an association between fluorescence and cardiovascular morbidity and mortality. We now report the presence of a major fluorophore (LW-1) in human skin collagen which increases with age, diabetes, and ESRD. It has a molecular weight of 623.2 Da, a UV maximum at 348 nm, and involves a lysine residue in an aromatic ring. LW-1 could not be synthesized using traditional glycation chemistry suggesting a complex mechanism of formation, perhaps related to hypoxia since elevated levels were also found in nondiabetic individuals with chronic lung disease.