Malnutrition-inflammation syndrome is associated with endothelial dysfunction in peritoneal dialysis patients

Endothelial dysfunction with atherosclerosis is a recognized complication of uremic patients. The hypoalbuminemia of peritoneal dialysis (PD) patients can induce a hypercoagulable and atherogenic state. In this study, we investigated the role played by malnutrition-inflammation syndrome on endothelial function markers in PD patients. We measured markers of nutrition [normalized protein catabolic rate (nPCR), albumin, prealbumin, insulin-like growth factor 1 (IGF-1), transferrin, and cholesterol], markers of endothelial damage and function [tissue-type plasminogen activator (tPA), thrombomodulin (TM), von Willebrand factor (vWF), and NO3 (representing NO)], markers of a coagulable state [fibrinogen and plasminogen activator inhibitor 1 (PAI-1)], markers of inflammation [tumor necrosis factor alpha (TNF alpha) and C-reactive protein (CRP)], and other endothelial injury factors [lipoprotein(a) [Lp(a)] and homocysteine]. We also performed an endothelial stimulation test consisting of right-arm venous occlusion (VO) for 10 minutes. The patients were divided into four groups according to their clinical atherosclerotic score (CAS). We studied 45 clinically stable PD patients. At baseline, statistically significant negative linear correlations were found between albumin and age (r = -0.54, p < 0.05), albumin and vWF post-VO (r = -0.54, p < 0.05), and albumin and TM (r = -0.36, p < 0.05), which are endothelial damage markers and prothrombotic factors. A positive linear correlation was seen between albumin and NO3 post-VO (r = 0.48, p < 0.05), indicating a high vasodilatation capacity. C-Reactive protein and TNF alpha showed a positive linear correlation (r = 0.5, p < 0.01). Similarly, TNF alpha showed a positive linear correlation with cardiovascular risk markers such as fibrinogen (r = 0.79, p < 0.01), PAI-1 (r = 0.44, p < 0.05), and homocysteine (r = 0.37, p < 0.05). Creatinine clearance showed a negative linear correlation with TM (r = -0.36, p < 0.05). Patients with albumin < 4 g/dL showed a lower tPA ratio, lower NO3, and a higher CRP, TNF alpha, and Lp(a) than did patients with albumin > 4 g/dL [tPA ratio: 2.1 +/- 1.56 (n = 29) vs. 2.6 +/- 2.3 (n = 16), p < 0.05; NO3: 47 +/- 27 micrograms/mL vs. 69 +/- 33 micrograms/mL, p < 0.05; CRP: 1.8 +/- 3 mg/dL vs. 1.1 +/- 1.6 mg/dL, p < 0.05; TNF alpha: 44.4 +/- 16 pg/mL vs. 36.6 +/- 21.4 pg/mL, p < 0.05; Lp(a): 55 +/- 39 mg/dL vs. 33 +/- 21 mg/dL, p < 0.05]. Patients with a worse CAS showed higher homocysteine levels and lower albumin values. Those relationships were maintained in both periods of the study. We found no relationships between dialysis dose and endothelial function markers. In conclusion, malnutrition-inflammation syndrome may contribute to endothelial dysfunction and, consequently, to prothrombotic and proatherogenic processes in PD patients.