Effect of unfractionated and low-molecular-weight heparin on OPG, sRANKL, and von Willebrand factor concentrations during hemodialysis.
BACKGROUND
Endothelial dysfunction marker, von Willebrand factor (vWF), is physically connected with osteoprotegerin (OPG) in the Weibel-Palade bodies. We aimed to compare the effect of unfractionated (UFH) and low-molecular-weight (LMWH enoxaparin) heparin used as anticoagulants during hemodialysis (HD) on plasma levels and relationships of OPG, soluble receptor activator of nuclear factor κB Ligand (sRANKL), and vWF.


METHODS
Totally 21 clinically stable chronic HD patients were randomly assigned to either enoxaparin (n = 10) or UFH (n = 11) anticoagulation and followed prospectively for 12 weeks before crossing over to the alternate therapy for further 12 weeks. The OPG, RANKL, and vWF levels were measured at T0, T10, and T180 of HD session after each period of evaluation.


RESULTS
The baseline sRANKL level was higher under UFH treatment. Its over-HD level does not behave significantly different under enoxaparin and UFH treatment. Plasma OPG levels expressly changed during both enoxaparin (χ(2) analysis of variance [ANOVA] = 31.13, P < .016) and UFH (χ(2) ANOVA = 8.26, P = .016) anticoagulation, and its increment at T10 and T180 was significantly different between both the heparins. The main negative predictor of OPG concentration was the total cholesterol level (β = -.51, P = .025). von Willebrand factor concentration remained stable during UFH anticoagulation, whereas constant, no significant increments were noticed, under enoxaparin treatment. After 10 minutes of HD, especially under enoxaparin use, a positive correlation between OPG and vWF increase was noticed (P = .03, R = .45).


CONCLUSIONS
Impact of heparin on endothelial cells and simultaneously on OPG/RANK/RANKL axis reinforces the presumption of the pathophysiological linkage between bone mineralization and endothelial dysfunction in end-stage renal disease.