Plasma pentosidine is associated with inflammation and malnutrition in end-stage renal disease patients starting on dialysis therapy

Abstract

Pentosidine is an advanced glycation end-product (AGE), formed by glycosylation and oxidation, that accumulates markedly in end-stage renal disease (ESRD). It has been speculated that AGE and carbonyl stress contributes to long-term complications such as cardiovascular disease (CVD) in ESRD patients. This study determined plasma levels of pentosidine as well as the presence of inflammation (CRP > or = 10 mg/L), clinical CVD (CVD(clin)), and malnutrition (subjective global assessment [SGA] > 1) in a cohort of 191 ESRD patients, median age of 55 yr (range, 23 to 70 yr) and median GFR = 7 ml/min (range, 2 to 17 ml/min), close to start of renal replacement therapy. Fifty-one elderly subjects, median age of 82 yr (range, 71 to 110 yr), with mild renal impairment, median GFR = 67 ml/min (range, 38 to 113 ml/min), were also studied for comparative analysis of plasma pentosidine. The plasma pentosidine content was elevated in all patients compared with the levels in the elderly subjects and were negatively correlated with GFR both in the ESRD patients (Rho = -0.24; P < 0.01; n = 159) and in the elderly subjects (Rho = -0.31; P < 0.05). Moreover, the plasma pentosidine content was correlated with age in the ESRD patients (Rho = 0.26; P < 0.001) and in the elderly subjects (Rho = 0.44; P < 0.001). The 63 malnourished ESRD patients (35%) had a significantly higher (P < 0.05) median plasma pentosidine than the well-nourished patients (39 versus 27 pmol/mg albumin). Similarly, 73 inflamed patients (38%) had a significantly higher (P < 0.001) median pentosidine content compared with 118 non-inflamed patients (37 versus 24 pmol/mg albumin). Also, the plasma pentosidine content showed weak but significant positive correlations with CRP (Rho = 0.28; P < 0.0001), fibrinogen (Rho = 0.23; P < 0.01; n = 126), IL-6 (Rho = 0.22; P < 0.01; n = 169), and soluble vascular cellular adhesion molecule-1 (Rho = 0.38; P < 0.001; n = 74). On the other hand, no significant differences in plasma pentosidine content were noted between the patients with and those without CVD(clin) (32 versus 27 pmol/mg albumin, respectively). Analyses of all-cause mortality, by Kaplan-Meier, showed that mortality was not linked to the plasma pentosidine content. Moreover, survival analysis by the Cox regression model showed that age (P < 0.001), diabetes mellitus (P < 0.01), malnutrition (P < 0.01), and CVD(clin) (P < 0.01) independently predicted poor outcome, whereas an elevated plasma pentosidine content did not. The present study shows that an elevated plasma pentosidine content in ESRD patients is significantly associated with both inflammation and malnutrition and confirms that low residual renal function and high age further contribute to an increased plasma pentosidine content. However, in this small cohort, the plasma pentosidine content did not predict outcome. Thus, accumulation of plasma pentosidine is unlikely to be an appropriate clinically useful marker to predict mortality in ESRD patients.