IMPROVEMENT OF SICKLE CELL DEFORMABILITY BY PIRACETAM IN VITRO AND IN VIVO

Piracetam (P) (2-oxo-pyrrolidine acetamide) has Theological properties and has been used at various dosages over the past decade for the management of psychosenescent syndromes. On maintenance therapy, at the oral dosage of 160 mg/kg/day, in four divided doses, P reduces the number of vaso-occlusive crises in sickle cell homozygous patients, to about a fifth of what could be expected without drug. After oral intake at the latter dosage P's bioavailability in the blood ranges from 0.5to 1 m mol/1. Microsieving on polycarbonate filters, 5 μ m por size, of diluted suspensions (haematocrit 1%) of oxygenated HbSS cells previously incubated with P 0.5 to 1 m mol/1, shows that the drug strongly improves their deformabi1ity. Similarly, microsieving of oxygenated HbSS cells obtained from patients on maintenance therapy with P, shows that the drug enhances the deformabi 1 ity of these cells as actively as it does in in vitro experiments in the same range of concentration. On the other hand the drug only poorly restores the loss of deformabi 1 ity of physiologically deoxygenated HbSS cells. From these experiments, it seems that P works rather on the outer viscoelastic properties of the HbSS red cell membrane than on the inner HbSS content of these cells.