Increased levels of soluble TNF-alpha receptors and cellular adhesion molecules in patients undergoing bioincompatible hemodialysis

Abstract

Background: The study aimed to differentiate the effects of hemodialysis (HD) and chronic renal failure (CRF) on the levels of circulating tumor necrosis factor-alpha (TNF-alpha) and TNF-alpha receptors p55 and p75, soluble vascular cell adhesion molecule-1 (sVCAM-1), intercellular adhesion molecule-1 (sICAM-1), soluble endothelial-leukocyte adhesion molecule-1 (sE-selectin) and sP-selectin in 18 patients on regular HD treatment with cuprophane membrane in relation to 15 non-dialyzed CRF patients and 15 healthy controls.

Methods: The serum concentrations were determined with standard ELISA assays.

Results: Blood serum p75 and p55 were approximately tenfold increased in CRF (36.7 +/- 6.2 and 27.1 +/- 5.6 ng/ml) and HD patients (45.6 +/- 18.4 and 28.7 +/- 5.9 ng/ml) before the HD session (HD 0), during (HD 20) the session (45.7 +/- 18.4 and 28.5 +/- 7.3 ng/ml) and after (HD 240) the HD session (52.1 +/- 17.4 and 30.9 +/- 8.2 ng/ml) in comparison to control values (5.6 +/- 1.3 and 2.4 +/- 0.8 ng/ml, respectively) (p < 0.01). The highest increment of p75 at the end of HD session (HD 240) was also significantly higher than at preceding time points (HD 0 and 20) (p < 0.05). However, the remaining study parameters did not change during an HD session. Also, there were no relevant changes in TNF-alpha levels if (HD 0) 22.7 +/- 21.5 ng/ml and (HD 240) 21.1 +/- 18.9 ng/ml were compared. Chronic HD status was related to the increase of sVCAM-1 and sICAM-1 levels. Prior to HD, T0 sVCAM-1 and sICAM-1 concentrations were 2,180.4 +/- 761.8 and 567.3 +/- 218.8 ng/ml, during HD (T20): 2,172.7 +/- 759.2 and 602.3 +/- 379.9 ng/ml, and after HD (T240): 2,401.6 +/- 756.4 and 648.3 +/- 183.5 ng/ml, respectively (p < 0.05 vs. controls and CRF patients). sVCAM-1 and sICAM-1 serum levels (1,262.2 +/- 472.9 and 165.6 +/- 50.4 ng/ml) were similar in CRF patients and healthy controls (854.4 +/- 241.5 and 217.6 +/- 74.2 ng/ml, respectively). Even though serum sE- and sP-selectin in CRF patients did not differ from the control (39.8 +/- 21.3 vs. 42.1 +/- 18.9 ng/ml and 187.9 +/- 66.9 vs. 198.8 +/- 62.2 ng/ml, respectively), their levels were increased in HD patients up to 111.9 +/- 54.6 and 453.2 +/- 231.1 ng/ml in patients prior to HD, 118.7 +/- 66.2 and 350.8 +/- 114.8 ng/ml during the HD session and then 132.3 +/- 61.1 and 368.3 +/- 126.6 ng/ml, respectively, after its completion (p < 0.05 in comparison with CRF patients and controls).

Conclusions: The increased circulating TNF-alpha receptors appear more associated with the uremic milieu than HD-related systemic inflammation, whereas increased soluble cellular adhesion molecules in patients undergoing bioincompatible HD may be related to the enhanced systemic inflammation specifically due to maintenance HD.