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Background: Endothelial injury, hypercoagulability, and decreased blood flow are suspected to play a key role in thrombosis,multiorgan failure, and death of patients with COVID-19. The link between increased blood viscosity and COVID-19- related complications and severity is not formerly established and can only be suspected. Aim(s): The aim of this study was to (1) analyze blood viscosity, red blood cell (RBC) deformability, and aggregation in hospitalized patients with Coronavirus disease 19 (COVID-19);(2) test the associations between impaired blood rheology and blood coagulation;and (3) test the associations between impaired blood rheology and several indicators of clinical severity. Method(s): A total of 172 patients with COVID-19, hospitalized in COVID-unit of the Internal Medicine Department (Lyon, France) participated in this study between January and May 2021. Clinical parameters were collected for each patient. Routine hematological/ biochemical parameters, blood viscosity, RBC deformability and aggregation, and RBC senescence markers were measured on the first day of hospitalization. A control group of 38 healthy individuals was constituted to compare the blood rheological and RBC profile. Rotational thromboelastography was performed in 76 patients to study clot formation dynamics. Result(s): Our study demonstrated that patients with COVID-19 had increased blood viscosity despite lower hematocrit than healthy individuals, as well as increased RBC aggregation. In-vitro experiments demonstrated a strong contribution of plasma fibrinogen in this RBC hyper-aggregation. RBC aggregation correlated positively with clot firmness, negatively with clot formation time, and positively with the length of hospitalization. Patients with oxygen supplementation had higher RBC aggregation and blood viscosity than those without, and patients with pulmonary lesions had higher RBC aggregation and enhanced coagulation than those without. Conclusion(s): This study is the first to demonstrate blood hyper-viscosity and RBC hyper-aggregation in a large cohort of patients with COVID-19 and describe associations with enhanced coagulation and clinical outcomes.
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Objective: The purpose is to identify the peculiarities of the parameters of red blood cells (RBC) and hemostasis in patients with strokes associated with coronavirus infection. Design and method: A total of 124 patients (48.5 + 1.9 years) with impairments of cerebral circulation due to COVID-19 (confirmed by positive PCR test) had been examined. Among them, 74 patients had ischemic stroke, 25- transient ischaemic attack, 17- intracerebral hemorrhage, 8- subarachnoid hemorrhage. The parameters of hemostasis were measured by standard methods, electrical, viscoelastic parameters of RBC - by dielectrophoresis. Results: 71 patients (the 1st group) showed signs of intravascular coagulation and thrombosis: accelerated platelet-leukocyte aggregation, increased levels of coagulation products, reduced fibrinolysis activity (p = 0.001-0.04). The levels of D-dimer, fibrinogen, ESR, platelet count were higher in this group compared to the second one (p < 0.01). A moderate increase of RBC summarized rigidity, viscosity was noted. The level of RBC hemolysis was associated with platelet count (r = 0.735,p = 0.03), D-dimer (r = 0.482, p < 0.05), fibrinogen level (r = 0.374, p = 0.04). In 2nd group (53 persons), the markers of thrombosis had moderate deviations. Sharply reduced RBC deformability with increased summarized rigidity, viscosity was dominant coupled with the background of high electrical conductivity of cell membranes compared to the indicators in the 1st group (p < 0.01). There was a decrease of membrane capacity, surface charge, cell dipole moment, polarizability than those in the 1st group (p = 0.0001-0.05). A sharp decrease of RBC deformability creates obstacles to overcoming small-diameter capillaries, leading to violations of microcirculatory blood flow. RBC deformability was associated with levels of ferritin (r = 0.451, p = 0.02), HbA1c (r = 0.480, p = 0.03), uric acid (r = -0.371, p < 0.05), LDL cholesterol (r = 0.461, p = 0.02). Incubation of blood samples in vitro for 10 min with riboflavin, nicotinamide, inosine, which ensures RBC energy metabolism, restored the reduced RBC deformability (p < 0.01), altered cell morphology (p = 0.04), decreased RBC aggregation (p < 0.001). Conclusions: The revealed features of parameters of RBC hemostasis in stroke patients with coronavirus infection are associated with two independent pathogenetic mechanisms: thrombotic and hemorheologic. The thrombotic variant is due to procoagulant state and an activity of inflammation. The hemorheologic variant is caused by decrease of RBC energy metabolism, activity of enzymes.
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COVID-19 is a new out-breaking human disease characterized by a severe acute respiratory syndrome caused by Coronavirus 2 (SARS-CoV-2). A pandemic state was swiftly declared by the World Health Organization due its fast transmissibility and huge human mortality index. After a brief introduction to the COVID-19 disease such as the ways of virus transportation inside the human body, the aim of this revision is to focus on the SARS-CoV2 infected erythrocyte properties which are considered biomarkers of COVID-19 patients and highlight the erythrocyte as a transporter for therapeutic drugs deliver in infected patients.