Association of POC-based Measurement of Skin AGEs with Serum AGEs as well as AGE Biomarkers in Individuals with and without Glucose Intolerance.

Abstract

The study group comprised individuals with normal glucose tolerance (NGT: n = 47) and with AGT, that is, either diabetes or prediabetes (n = 68). Intrinsic AGE fluorescence was measured spectrofluorimetrically using multimode plate reader in the serum by exciting the samples at 370 nm and emission readouts at 440 nm. Skin AGEs were acquired using a CE-marked Scout DS commercial device. Serum levels of biomarkers carboxymethyl lysine (CML), carboxyethyl lysine (CEL), and pentosidine were analyzed by enzyme-linked immunosorbent assay (ELISA). In subjects with AGT, the skin AGEs [61.3 vs 53.7 arbitrary units (AU), p<0.0001] and serum AGEs (3.5 vs 2.8 AU, p<0.0001) were significantly higher than in individuals with NGT. The levels of CML, CEL, and pentosidine were also significantly higher in the subjects with AGT when compared with NGT (138 vs 89 pg/mL; 2.4 vs 1.4 nmol/mL, and 64 vs 48 pmol/mL, p<0.0001), respectively. Pearson correlation analysis showed a significant positive association of skin AGEs with serum AGEs (r = 0.344) (p<0.001), CML (r = 0.323) (p<0.001), CEL (r = 0.308) (p<0.001), and pentosidine (r = 0.251) (p<0.001). In addition, it also showed a positive correlation with fasting plasma glucose (FPG) (p<0.001), 2-hour post-glucose (p<0.001), glycated hemoglobin (HbA1c) (p<0.001), and body mass index (BMI) (p<0.05). Multiple logistic regression analysis using AGT as a dependent variable showed that skin AGE scores were significantly (p<0.001) associated with AGT (odds ratio: 1.133, confidence intervals: 1.067-1.203). This study shows that the measurement of skin AGEs using a POC device may be suitable for mass screening of AGT even in low-resource settings.