Portal de Periódicos da CAPES

Rheological properties of rosettes formed by red blood cells parasitized by Plasmodium falciparum

1992; Wiley; Volume: 82; Issue: 4 Linguagem: Inglês

10.1111/j.1365-2141.1992.tb06955.x

1365-2141

Gerard B. Nash, Brian M. Cooke, Johan E. Carlson, Mats Wahlgren,

Mosquito-borne diseases and control

A proportion of red blood cells parasitized by Plasmodium falciparum form rosettes with non‐parasitized red cells. Although these rosettes are thought to impair microcirculatory flow, their rheological characteristics have not been fully described. Using dual‐micropipette manipulation to pull apart individual rosettes, we found that the forces binding rosettes together were strong (average force for removal of a cell was 4.4 10‐ 10 N, approximately 5 times that required to detach a parasitized cell adhered to cultured endothelium). If disrupted rosettes were re‐formed, cells resetted immediately on contact, but the strength of attachment increased over minutes, and did not apparently reach its maximal level for hours. All non‐parasitized cells tested could adhere to rosette‐forming parasitized cells. Rosettes could withstand arterial flow stresses (1.4–1.6 Pa) for minutes without disintegration. To test the effects of resetting on flow resistance, the time required for entry into a 4.3 μm pipette was measured. Entry times depended strongly on the number of cells in the rosette, and averaged 35 times longer than for non‐parasitized cells. Our studies show that the cell‐cell attachments within rosettes are strong, and suggest that rosettes might survive both the arterial circulation and passage through microvessels and could contribute to the ischaemic complications of falciparum malaria.