title: Blood thixotropy in patients with sickle cell anaemia: role of haematocrit and red blood cell rheological properties.
abstract: We compared the blood thixotropic/shear-thinning properties and the red blood cells' (RBC) rheological properties between a group of patients with sickle cell anaemia (SS) and healthy individuals (AA). Blood thixotropy was determined by measuring blood viscosity with a capillary viscometer using a "loop" protocol: the shear rate started at 1 s-1 and increased progressively to 922 s-1 and then re-decreased to the initial shear rate. Measurements were performed at native haematocrit for the two groups and at 25% and 40% haematocrit for the AA and SS individuals, respectively. RBC deformability was determined by ektacytometry and RBC aggregation properties by laser backscatter versus time. AA at native haematocrit had higher blood thixotropic index than SS at native haematocrit and AA at 25% haematocrit. At 40% haematocrit, SS had higher blood thixotropic index than AA. While RBC deformability and aggregation were lower in SS than in AA, the strength of RBC aggregates was higher in the former population. Our results showed that 1) anaemia is the main modulator of blood thixtropy and 2) the low RBC deformability and high RBC aggregates strength cause higher blood thixotropy in SS patients than in AA individuals at 40% haematocrit, which could impact blood flow in certain vascular compartments.
authors.affiliation: Inserm UMR 1134, Hôpital Ricou, CHU de Pointe-à-Pitre, 97157, Pointe-à-Pitre, Guadeloupe, France.
authors.forename: Jens
authors.initials: J
authors.lastname: Vent-Schmidt
authors.affiliation: Inserm UMR 1134, Hôpital Ricou, CHU de Pointe-à-Pitre, 97157, Pointe-à-Pitre, Guadeloupe, France; Laboratory of Excellence GR-Ex « The red cell: from genesis to death », PRES Sorbonne Paris Cité, 75015, Paris, France; Laboratory ACTES (EA 3596), Department of Physiology, French West Indies and Guiana University, Pointe-à-Pitre, Guadeloupe, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Waltz
authors.affiliation: Inserm UMR 1134, Hôpital Ricou, CHU de Pointe-à-Pitre, 97157, Pointe-à-Pitre, Guadeloupe, France; Laboratory of Excellence GR-Ex « The red cell: from genesis to death », PRES Sorbonne Paris Cité, 75015, Paris, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Romana
authors.affiliation: Inserm UMR 1134, Hôpital Ricou, CHU de Pointe-à-Pitre, 97157, Pointe-à-Pitre, Guadeloupe, France; Laboratory of Excellence GR-Ex « The red cell: from genesis to death », PRES Sorbonne Paris Cité, 75015, Paris, France.
authors.forename: Marie-Dominique
authors.initials: MD
authors.lastname: Hardy-Dessources
authors.affiliation: Unité Transversale de la Drépanocytose, CHU de Pointe-à-Pitre, 97157, Pointe-à-Pitre, Guadeloupe, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Lemonne
authors.affiliation: Unité Transversale de la Drépanocytose, CHU de Pointe-à-Pitre, 97157, Pointe-à-Pitre, Guadeloupe, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Billaud
authors.affiliation: Inserm UMR 1134, Hôpital Ricou, CHU de Pointe-à-Pitre, 97157, Pointe-à-Pitre, Guadeloupe, France; Laboratory of Excellence GR-Ex « The red cell: from genesis to death », PRES Sorbonne Paris Cité, 75015, Paris, France; Unité Transversale de la Drépanocytose, CHU de Pointe-à-Pitre, 97157, Pointe-à-Pitre, Guadeloupe, France.
authors.forename: Maryse
authors.initials: M
authors.lastname: Etienne-Julan
authors.affiliation: Inserm UMR 1134, Hôpital Ricou, CHU de Pointe-à-Pitre, 97157, Pointe-à-Pitre, Guadeloupe, France; Laboratory of Excellence GR-Ex « The red cell: from genesis to death », PRES Sorbonne Paris Cité, 75015, Paris, France; Institut Universitaire de France, Paris, France; Laboratoire CRIS EA647, Université Claude Bernard Lyon 1, 69100, Villeurbanne, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Connes
mesh_terms: D000755:Anemia, Sickle Cell / Q000503:physiopathology*; D016022:Case-Control Studies; D004903:Erythrocyte Aggregation; D004907:Erythrocyte Deformability; D004912:Erythrocytes / Q000473:pathology*; D006400:Hematocrit; D018056:Hemorheology; D006801:Humans