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Blood thixotropy in patients with sickle cell anaemia: role of haematocrit and red blood cell rheological properties.

Vent-Schmidt J, Waltz X, Romana M, Hardy-Dessources MD, Lemonne N, Billaud M, Etienne-Julan M, Connes P - PLoS ONE (2014)

Bottom Line: 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.RBC deformability was determined by ektacytometry and RBC aggregation properties by laser backscatter versus time.While RBC deformability and aggregation were lower in SS than in AA, the strength of RBC aggregates was higher in the former population.

View Article: PubMed Central - PubMed

Affiliation: Inserm UMR 1134, Hôpital Ricou, CHU de Pointe-à-Pitre, 97157, Pointe-à-Pitre, Guadeloupe, France.

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.

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A–E: Haematocrit (Hct; 1A), red blood cell aggregation index (AI; 1B), red blood cell aggregates strength (disaggregation threshold; 1C), plasma viscosity (1D) and time for red blood cell shape recovery (1E) in patients with sickle cell anaemia (SS) and healthy individuals (AA). Significant difference: *p<0.05; ***p<0.001.
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pone-0114412-g001: A–E: Haematocrit (Hct; 1A), red blood cell aggregation index (AI; 1B), red blood cell aggregates strength (disaggregation threshold; 1C), plasma viscosity (1D) and time for red blood cell shape recovery (1E) in patients with sickle cell anaemia (SS) and healthy individuals (AA). Significant difference: *p<0.05; ***p<0.001.

Mentions: As expected, native Hct was lower in SS than in AA (Fig. 1A, p<0.001). While RBC aggregation (AI) was lower in SS than in AA (p<0.05), the RBC disaggregation threshold was 3 fold higher in the former group (p<0.001). Plasma viscosity tended to be slightly greater in the SS group (p = 0.07). At all shear stress levels, except the lowest one, SS had lower RBC deformability than AA (Table 2, p<0.001). The time for RBC shape recovery calculated from the syllectogram was shorter in SS than in AA (Fig. 1E, p<0.001).


Blood thixotropy in patients with sickle cell anaemia: role of haematocrit and red blood cell rheological properties.

Vent-Schmidt J, Waltz X, Romana M, Hardy-Dessources MD, Lemonne N, Billaud M, Etienne-Julan M, Connes P - PLoS ONE (2014)

A–E: Haematocrit (Hct; 1A), red blood cell aggregation index (AI; 1B), red blood cell aggregates strength (disaggregation threshold; 1C), plasma viscosity (1D) and time for red blood cell shape recovery (1E) in patients with sickle cell anaemia (SS) and healthy individuals (AA). Significant difference: *p<0.05; ***p<0.001.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263608&req=5

pone-0114412-g001: A–E: Haematocrit (Hct; 1A), red blood cell aggregation index (AI; 1B), red blood cell aggregates strength (disaggregation threshold; 1C), plasma viscosity (1D) and time for red blood cell shape recovery (1E) in patients with sickle cell anaemia (SS) and healthy individuals (AA). Significant difference: *p<0.05; ***p<0.001.
Mentions: As expected, native Hct was lower in SS than in AA (Fig. 1A, p<0.001). While RBC aggregation (AI) was lower in SS than in AA (p<0.05), the RBC disaggregation threshold was 3 fold higher in the former group (p<0.001). Plasma viscosity tended to be slightly greater in the SS group (p = 0.07). At all shear stress levels, except the lowest one, SS had lower RBC deformability than AA (Table 2, p<0.001). The time for RBC shape recovery calculated from the syllectogram was shorter in SS than in AA (Fig. 1E, p<0.001).

Bottom Line: 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.RBC deformability was determined by ektacytometry and RBC aggregation properties by laser backscatter versus time.While RBC deformability and aggregation were lower in SS than in AA, the strength of RBC aggregates was higher in the former population.

View Article: PubMed Central - PubMed

Affiliation: Inserm UMR 1134, Hôpital Ricou, CHU de Pointe-à-Pitre, 97157, Pointe-à-Pitre, Guadeloupe, France.

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.

Show MeSH
Related in: MedlinePlus