In vitro effects of co-incubation of blood with artemether/lumefantrine & vitamin C on the viscosity & elasticity of blood.

Background & objectives: The antimalarial combination drug artemether/lumefantrine has been shown to be effective against malaria parasite through its haemolytic action. This drug is sometimes co-administered with vitamin C in patients with malaria. Vitamin C is associated with antioxidant properties which would be expected to protect against haemolytic effects of this antimalarial drug. This study was designed to investigate in vitro effects of co-incubation of artemether/lumefantrine with vitamin C on the viscosity and elasticity of blood. Methods: Blood was collected from 12 healthy female volunteers with normal haemoglobin genotype (HbAA). A Bioprofiler was used to measure the viscosity and elasticity of untreated blood samples (control) and samples exposed to artemether/lumefantrine (0.06/0.36 mg/ml) alone and with low or high dose vitamin C (equivalent to adult doses of 100 or 500 mg). Results: Artemether/lumefantrine significantly (P<0.05) reduced viscosity of blood from 4.72 ± 0.38 to 3.78 ± 0.17 mPa.s. Addition of vitamin C (500 mg) further reduced blood viscosity to 2.67 ± 0.05 mPa.s. The elasticity of blood was significantly (P<0.05) reduced from 0.33 ± 0.04 mPa.s to 0.24 ± 0.03 mPa.s by the antimalarial drug, and further reduced to 0.13 ± 0.02 mPa.s in the presence of vitamin C (500 mg). Interpretation & conclusions: Co-incubation of blood with vitamin C and antimalarial combination drug potentiates the haemolytic effects of the latter on reducing blood viscosity and elasticity in vitro. This may possibly have implications in relation to haemolysis in patients receiving vitamin C supplementation with artemether/lumefantrine during malaria therapy.

Is there hyperviscosity in Pre-eclampsia?

There are conflicting reports on blood viscosity and its determinants in pre-eclampsia. We investigated the presence of hyperviscosity and its determinants in 24 nulliparous, pre-eclamptic Jamaican women. An equal number of non-pre-eclamptic, gestation-matched women served as controls. There was no statistically significant difference in whole blood, plasma and serum viscosities, as well as their determinants, namely, haematocrit, fibrinogen, IgM and IgG concentrations between the pre-eclamptic and control groups. This suggests that hyperviscosity is not a feature of pre-eclampsia in this Jamaican population.