Prognostic utility of plasma S100A12 levels to establish a novel scoring system for predicting mortality in maintenance hemodialysis patients: a two-year prospective observational study in Japan.

BACKGROUND: S100A12 protein is an endogenous receptor ligand for advanced glycation end products. In this study, the plasma S100A12 level was assessed as an independent predictor of mortality, and its utility in clinical settings was examined. METHODS: In a previous cross-sectional study, plasma S100A12 levels were measured in 550 maintenance hemodialysis patients to determine the association between S100A12 and the prevalence of cardiovascular diseases (CVD). In this prospective study, the risk of mortality within a two-year period was determined. An integer scoring system was developed to predict mortality on the basis of the plasma S100A12 levels. RESULTS: Higher plasma S100A12 levels (≥18.79 ng/mL) were more closely associated with higher all-cause mortality than lower plasma S100A12 levels (<18.79 ng/mL; P = 0.001). Multivariate Cox proportional hazards analysis revealed higher plasma S100A12 levels [hazard ratio (HR), 2.267; 95% confidence interval (CI), 1.195-4.302; P = 0.012], age ≥65 years (HR, 1.961; 95%CI, 1.017-3.781; P = 0.044), serum albumin levels <3.5 g/dL (HR, 2.198; 95%CI, 1.218-3.968; P = 0.012), and history of CVD (HR, 2.068; 95%CI, 1.146-3.732; P = 0.016) to be independent predictors of two-year all-cause mortality. The integer score was derived by assigning points to these factors and determining total scores. The scoring system revealed trends across increasing scores for predicting the all-cause mortality [c-statistic = 0.730 (0.656-0.804)]. The resulting model demonstrated good discriminative power for distinguishing the validation population of 303 hemodialysis patients [c-statistic = 0.721 (0.627-0.815)]. CONCLUSION: The results indicate that plasma S100A12 level is an independent predictor for two-year all-cause mortality. A simple integer scoring system was therefore established for predicting mortality on the basis of plasma S100A12 levels.

Increased plasma S100A12 (EN-RAGE) levels in hemodialysis patients with atherosclerosis.

BACKGROUND: S100A12, also known as EN-RAGE (extracellular newly identified receptor for advanced glycation end products binding protein) is a ligand for RAGE, and has been proposed to contribute to the development of atherosclerosis. In this study, we examined the plasma S100A12 concentration in patients with ESRD and undergoing hemodialysis (HD) and evaluated the relation between S100A12 level and carotid intimal media thickness (IMT) by ultrasound. METHODS: We measured plasma S100A12 concentration in 72 HD patients and 42 control subjects. IMT of the carotid artery was measured by high-resolution B-mode ultrasonography in 46 HD patients. RESULTS: The mean plasma S100A12 level was 2.3-fold higher in HD patients than in control subjects (25.0 +/- 2.32 vs. 10.7 +/- 0.97 ng/ml, p < 0.001). Stepwise multiple regression analysis identified circulating white blood cell count as a positive independent determinant and total cholesterol and serum albumin levels as negative independent determinants of plasma S100A12 concentration. The maximum IMT was positively correlated with plasma S100A12 level. Stepwise multiple regression analysis also identified plasma S100A12 as a significant independent determinant of the maximum IMT. CONCLUSION: These findings suggest that S100A12 protein is involved in the acceleration of atherosclerosis in HD patients.

Increased plasma S100A12 (EN-RAGE) levels in patients with type 2 diabetes.

S100A12, also called EN-RAGE (extracellular newly identified receptor for advanced glycation end products binding protein) or calcium-binding protein in amniotic fluid-1, is a ligand for RAGE. It has been shown that S100A12 induces adhesion molecules such as vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 in the vascular endothelial cell and mediates migration and activation of monocytes/macrophages through RAGE binding and that infusion of lipopolysaccharide into mice causes time-dependent increase of S100A12 in the plasma. Therefore, circulating S100A12 protein may be involved in chronic inflammation in the atherosclerotic lesion. In this study, we developed an ELISA system that uses specific monoclonal antibodies against recombinant human S100A12 to measure plasma S100A12 levels in patients with diabetes. On using our S100A12 ELISA system, the coefficients of variation of intra- and interassay were less than 4 and 9%, respectively. The analytical lower detection limit was 0.2 ng/ml. When plasma S100A12 levels were measured by this system, the concentrations were more than twice as high in the patients with diabetes, compared with those without. Using univariate analysis in all subjects, plasma S100A12 concentrations correlated with hemoglobin A1c, fasting glucose, high-sensitivity C-reactive protein and white blood cell count. Stepwise multiple regression analyses, however, revealed that only white blood cell count and hemoglobin A1c remained significant independent determinants of plasma S100A12 concentration. These results suggest that plasma S100A12 protein levels are regulated by factors related to subclinical inflammation and glucose control in patients with type 2 diabetes.

Plasma S100A12 levels and peripheral arterial disease in end-stage renal disease.

BACKGROUND: S100A12 is an endogenous ligand of the receptor for advanced glycation end products (RAGE). Plasma S100A12 levels are high in end-stage renal disease (ESRD) patients undergoing maintenance hemodialysis (HD). Peripheral arterial disease (PAD) is common in HD patients and is associated with increased cardiovascular morbidity and mortality rates in this population. To date, however, no study has specifically assessed the relationship between plasma S100A12 and PAD in HD patients. METHODS: We conducted a cross-sectional study of 152 HD patients in our affiliated hospital. We investigated PAD history and patient characteristics and quantified plasma S100A12 levels in all participants. RESULTS: HD patients with PAD (n = 26; 21.9 [13.6-33.4] ng/ml) showed significantly higher plasma S100A12 levels than HD patients without PAD (n = 126; 11.8 [7.5-17.6]ng/ml; p < 0.001). In multivariate logistic regression analysis, the plasma S100A12 level (odds ratio [OR] 5.71; 95% confidence interval [CI] 1.29-25.3; p = 0.022) was identified as an independent factor associated with PAD prevalence. Another factor associated with PAD prevalence was the ankle-brachial index (OR 0.54; 95% CI 0.40-0.74; p < 0.001). CONCLUSION: These results suggest that plasma S100A12 levels are strongly associated with PAD prevalence in ESRD patients undergoing HD.

Plasma S100A12 level is associated with cardiovascular disease in hemodialysis patients.

BACKGROUND AND OBJECTIVES: S100A12 is an endogenous receptor ligand for advanced glycation end products. Cardiovascular disease remains a major cause of morbidity and mortality in patients with chronic kidney disease. In this study, we report cross-sectional data on 550 hemodialysis patients and assess the relationship between plasma S100A12 level and cardiovascular disease. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A cross-sectional study of 550 maintenance hemodialysis patients was conducted. We investigated the past history of cardiovascular disease and quantified the plasma level of S100A12 protein in all participants. RESULTS: Plasma S100A12 level was higher in hemodialysis patients with cardiovascular disease (n=197; 33.8 ± 28.1 ng/ml) than in those without it (n=353; 20.2 ± 16.1 ng/ml; P<0.001). In multivariate logistic regression analysis, the plasma S100A12 level (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.13 to 1.44; P<0.001) was identified as an independent factor associated with the prevalence of cardiovascular disease. The other factors associated with the prevalence of cardiovascular diseases were the presence of diabetes mellitus (OR, 2.81; 95% CI, 1.79 to 4.41; P < 0.001) and high-sensitivity CRP level (OR, 1.02; 95% CI, 1.00 to 1.05; P=0.046). Furthermore, the plasma S100A12 level (OR, 1.30; 95% CI, 1.09 to 1.54; P=0.004) was significantly associated with cardiovascular disease even in hemodialysis patients without diabetes mellitus (n=348). CONCLUSIONS: These results suggest that the plasma S100A12 protein level is strongly associated with the prevalence of cardiovascular disease in hemodialysis patients.