title: A Comparative Study on Skin and Plasma Advanced Glycation End Products and Their Associations with Arterial Stiffness.
abstract: BACKGROUND
  We compared skin and plasma measurements of advanced glycation end products (AGEs), with particular focus on their levels in the presence of hypertension or diabetes and prediabetes and their associations with arterial stiffness in outpatients with suspected or diagnosed hypertension.
  
  
  METHODS
  Skin AGE accumulation was measured as autofluorescence on the left forearm using the skin autofluorescence Reader and expressed in arbitrary units in the range from 0 to 25. Plasma AGE concentration was measured by the enzyme-linked immunosorbent assay method and logarithmically transformed for statistical analysis. Arterial stiffness was assessed by carotid-femoral pulse wave velocity (cfPWV) using the SphygmoCor system (Sydney, Australia).
  
  
  RESULTS
  The 218 participants (96 [44.0%] men, mean age 51.9 years) had a mean skin autofluorescence of 1.89 arbitrary units, plasma AGE concentration of 4.47 μg/ml, and cfPWV of 8.0 m/s. Skin autofluorescence was significantly correlated with plasma AGEs in diabetic or prediabetic patients (n= 31,r= 0.37,p= 0.04) but not in subjects with normoglycemia (n= 187,r= -0.05,p= 0.48). Nonetheless, both measurements were significantly (p≤ 0.001) higher in men (2.00 arbitrary units and 6.73 μg/ml, respectively) than women (1.81 arbitrary units and 3.60 μg/ml, respectively) and in diabetic or prediabetic (2.03 arbitrary units and 6.61 μg/ml, respectively) than normoglycemia subjects (1.87 arbitrary units and 4.17 μg/ml, respectively), but similar in hypertensive (n= 105) and normotensive subjects (n= 113,p≥ 0.35). In adjusted multiple regression analyses, plasma AGE concentration, but not skin autofluorescence (p≥ 0.37), was significantly associated with cfPWV in all subjects (β 0.44 m/s for each 10-fold increase;p= 0.04) and in subgroups of men and diabetes and prediabetes (β 0.12-0.55 m/s for each 10-fold increase;p≤ 0.02).
  
  
  CONCLUSIONS
  Although skin and plasma AGEs were similarly associated with gender and diabetes or prediabetes, they might measure something different and have different clinical relevance, such as for arterial stiffness.
authors.affiliation: Centre for Epidemiological Studies and Clinical Trials, Shanghai Key Laboratory of Hypertension, The Shanghai Institute of Hypertension, Department of Hypertension, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Chang-Yuan
authors.initials: CY
authors.lastname: Liu
authors.affiliation: Centre for Epidemiological Studies and Clinical Trials, Shanghai Key Laboratory of Hypertension, The Shanghai Institute of Hypertension, Department of Hypertension, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Qi-Fang
authors.initials: QF
authors.lastname: Huang
authors.affiliation: Centre for Epidemiological Studies and Clinical Trials, Shanghai Key Laboratory of Hypertension, The Shanghai Institute of Hypertension, Department of Hypertension, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Yi-Bang
authors.initials: YB
authors.lastname: Cheng
authors.affiliation: Centre for Epidemiological Studies and Clinical Trials, Shanghai Key Laboratory of Hypertension, The Shanghai Institute of Hypertension, Department of Hypertension, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Qian-Hui
authors.initials: QH
authors.lastname: Guo
authors.affiliation: Centre for Epidemiological Studies and Clinical Trials, Shanghai Key Laboratory of Hypertension, The Shanghai Institute of Hypertension, Department of Hypertension, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Centre for Epidemiological Studies and Clinical Trials, Shanghai Key Laboratory of Hypertension, The Shanghai Institute of Hypertension, Department of Hypertension, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Centre for Epidemiological Studies and Clinical Trials, Shanghai Key Laboratory of Hypertension, The Shanghai Institute of Hypertension, Department of Hypertension, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Ji-Guang
authors.initials: JG
authors.lastname: Wang
keywords: Advanced glycation end products; Arterial stiffness; Carotid-femoral pulse wave velocity; Diabetes; Plasma concentration; Prediabetes; Skin autofluorescence