Atrial natriuretic peptide does not degrade the endothelial glycocalyx: a secondary analysis of a randomized porcine model.

BACKGROUND The atrial natriuretic peptide released from the heart regulates intravascular volume and is suspected to increase capillary permeability. Contradictory results regarding ANP and glycocalyx degradation have been reported. The aim of this study was to investigate if an infusion of ANP causes degradation of the endothelial glycocalyx. METHODS Twenty pigs, pre-treated with 250 mg methylprednisolone, were randomized to receive an infusion of either ANP (50 ng/kg/min) (n = 10) or 0.9% NaCl (n = 10) during 60 minutes. Endothelial glycocalyx components (heparan sulphate proteoglycan and hyaluronic acid), Hct, calculated plasma volume and colloid osmotic pressure were measured from baseline to 60 minutes. RESULTS There was no difference between the control and intervention groups for heparan sulphate proteoglycan and hyaluronic acid corrected for the change in plasma volume (p = 0.333 and p = 0.197). Hct increased with 1.8 ± 2.2% in the intervention group (p = 0.029) with no change -0.5 ± 2.3% in the control group (p = 0.504). The plasma volume decreased in the intervention group with -8.4 ± 10% (p = 0.034) with no change in the control group 3.1 ± 12% (p = 0.427). Median changes in colloid osmotic pressures in the control and intervention group were -0.39 [95%CI, -1.88 to 0.13] and 0.9 [95%CI, 0.00 to 1.58], respectively (p = 0.012). CONCLUSIONS In this randomized porcine study an ANP infusion did not cause endothelial glycocalyx degradation but decreased the plasma volume most probably due to precapillary vasodilation and increased filtration.