Fibrinogen–erythrocyte binding and hemorheology measurements in the assessment of essential arterial hypertension patients

This journal is © The Royal Society of Chemistry 2019Some studies have reported a positive association between plasma fibrinogen levels, erythrocyte aggregation and essential arterial hypertension (EAH). The aim of this study was to understand how the interaction between fibrinogen and its erythrocyte membrane receptor is altered in EAH. EAH patients (n = 31) and healthy blood donors (n = 65) were enrolled in the study. EAH patients were therapeutically controlled for the disease, presenting a systolic blood pressure between 108 and 180 mmHg and a diastolic blood pressure between 66 and 123 mmHg. Clinical evaluation included blood pressure monitoring, electrocardiography, echocardiography and blood cell count. The hemorheological parameters were also analyzed. Fibrinogen–erythrocyte binding force and frequency were evaluated quantitatively, at the single-molecule level, using atomic force microscopy (AFM). Changes in erythrocyte elasticity were also evaluated. Force spectroscopy data showed that the average fibrinogen–erythrocyte binding forces increase from 40.4 ± 3.0 pN in healthy donors to 73.8 ± 8.1 pN in patients with EAH, despite a lower binding frequency for patients compared to the control group (7.9 ± 1.6% vs. 27.6 ± 4.2%, respectively). Elasticity studies revealed an increase of erythrocyte stiffness in the patients. The stronger fibrinogen binding to erythrocytes from EAH patients and alteration in cell elasticity may lead to changes in the whole blood flow. The patients’ altered hemorheological parameters may also contribute to these blood flow perturbations. The transient bridging of two erythrocytes, by the simultaneous binding of fibrinogen to both of them, promoting erythrocyte aggregation, could represent an important cardiovascular risk factor.This work was supported by Fundação para a Ciência e a Tecnologia – Ministério da Ciência, Tecnologia e Ensino Superior (FCT-MCTES, Portugal) grants PTDC/QUI-BIQ/119509/2010 and PTDC/BBB-BMD/6307/2014, as well as the fellowship SFRH/BD/84414/2012 to AFG. This work was also supported by the UID/BIM/50005/2019 project, funded by FCTMCTES through Fundos do Orçamento do Estado.