The influence of plasma cholesterol on whole blood and plasma viscosity

The plasma cholesterol concentration in a group of seven beagle dogs was increased to ∼1000 mg/100 ml with a high cholesterol diet. Measurements of the whole blood and plasma viscosity were made at various plasma cholesterol concentrations. The viscosity determinations were carried out using a cone and plate micro viscometer operated at 37°C and at shear rates of 11.5. 23, 46, 115 and 230 sec⁻¹. The whole blood samples were adjusted to a haematocrit of 40 per cent before the viscosity determination. It was found that viscosity of whole blood was dependent on the cholesterol concentration whilst plasma viscosity was unaffected. The increase in whole blood viscosity as a result of an increase in cholesterol level was more marked at the lower shear rates.