In vivo shear flow and erythrocyte membrane fluidity in hypertensive patients.
1. To evaluate the response of red blood cells subjected to the shear flow in hypertension, the relationships between wall shear phenomena determined in vivo in the brachial artery of hypertensive patients and the modifications of the membrane dynamics measured in vitro in erythrocyte ghosts of 32 patients were investigated. 2. Two fluorescent probes, diphenylhexatriene (DPH) and its trimethylamino-derivative (TMA-DPH), localized respectively in the lipid membrane core and at the lipid-water interface, were used. 3. Shear rate, shear stress and blood velocity were positively correlated with TMA-DPH anisotropy (P = 0.015, 0.005 and 0.026, respectively), but not with that of DPH. This indicates that wall shear forces were associated with the microviscosity of the outer part of the cell membrane. 4. The changes in wall shear forces and erythrocyte membrane microviscosity probed by TMA-DPH or DPH were observed to vary in parallel under nitrendipine therapy. 5. These results suggest that in vivo shear forces participate in the control of erythrocyte membrane fluidity or that erythrocytes adapt their membrane properties to blood flow conditions.
Le Sang Quan
K H
KH
CNRS URA 1482, Pharmacologie, Faculté de Médecine Necker-Enfants Malades, 75015 Paris, France.
Levenson
J
J
Del Pino
M
M
Simon
A
A
Devynck
M A
MA
D000959:Antihypertensive Agents / Q000627:therapeutic use; D001783:Blood Flow Velocity / Q000502:physiology; D004161:Diphenylhexatriene / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000502:physiology*; D005260:Female; D005456:Fluorescent Dyes / Q000378:metabolism; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology*; D008297:Male; D008560:Membrane Fluidity / Q000502:physiology*; D008875:Middle Aged; D013314:Stress, Mechanical
D000959:Antihypertensive Agents; D005456:Fluorescent Dyes; D004161:Diphenylhexatriene