Evidence that the degree of band 3 phosphorylation modulates human erythrocytes nitric oxide efflux – in vitro model of hyperfibrinogenemia
Issue title: Selected Proceedings of the 16th Conference of the European Society for Clinical Hemorheology and Microcirculation (ESCHM), 18–21 June, 2011, Munich, Germany
Affiliations: University of Lisbon Medical School, Santa Maria Hospital, Lisbon, Portugal | Institute of Biochemistry, Institute of Molecular Medicine, University of Lisbon Medical School, Lisbon, Portugal
Note: [] Corresponding author: J. Pedro Lopes de Almeida, Instituto de Bioquímica, Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Edifício Egas Moniz, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal. Tel.: +351 91 8985450; Fax: +351 21 7999477; E-mail: [email protected]
Abstract: Recent evidence has shown that plasma fibrinogen, a major cardiovascular risk factor, interacts with the erythrocyte membrane and acts to influence blood flow via erythrocyte nitric oxide (NO) modulation. In the present pioneer in-vitro study, whole blood samples were harvested from healthy subjects and aliquots were incubated in the absence (control aliquots) and presence of fibrinogen at different degrees of band 3 phosphorylation, and the levels of NO, nitrite, nitrate and S-nitroglutathione (GSNO) were determined. Hyperfibrinogenemia interferes with erythrocyte NO mobilization without changing its efflux in a way that seems to be dependent of the degree of band 3 phosphorylation. In presence of higher fibrinogen concentrations the NO efflux is reinforced when band 3 is phosphorylated (p < 0.001). Higher levels of nitrite, nitrate and GSNO were documented (p < 0.05). However, the mechanisms by which fibrinogen signalling modulates erythrocyte function remain to be clarified and are currently under study. These conditions may be considered an approach to be followed in blood storage for transfusions.
