Apelin, Plasmatic Osmolality and Hypotension in Dialyzed Patients.

Background/Aims: To evaluate the balance between arginine-vasopressin (AVP) and apelin during hemodialysis and its role in hypotension onset and in the inflammation status. Methods: We enrolled 50 patients chronically treated with hemodialysis. We assessed plasmatic osmolality, AVP, apelin, mean blood pressure (BP), high-sensitivity C-reactive protein (hsCRP) and β(2)-microglobulin. Results: Apelin rises during dialytic treatment (from 0.68 ± 0.34 to 1.89 ± 0.56 pg/ml, p < 0.0001), while plasmatic osmolality (from 325 ± 4.54 to 311 ± 1.20 mosm/kg H(2)O, p < 0.0001), AVP (from 4.28 ± 1.12 to 2.48 ± 0.50 pg/ml, p < 0.0001) and mean BP (from 124 ± 6 to 110 ± 7 mm Hg, p < 0.0001) decrease. At multivariate regression with respect to apelin, only mean BP remains (r = -0.95, p < 0.0001). We also correlated the AVP/apelin ratio with BP. Moreover, apelin is inversely related to hsCRP (r = -0.79, p < 0.0001). Conclusions: The AVP/apelin balance changes with plasmatic osmolality variations induced by hemodialytic sessions and could represent a physiopathological marker of arterial hypo- and hypertension. Finally, apelin appears inversely related to inflammation markers.