In vitro effect of nicotine on red blood cell deformability in untreated and treated essential hypertension

The in vitro effect of nicotine (10(-7) mol l-1) on red blood cell (RBC) deformability in essential hypertension, efficacy of antihypertensive treatment (with the combination of enalapril, nifedipine and indapamid) on hypertension-induced decrease in RBC deformability and interaction between nicotine and efficacy of antihypertensive treatment were investigated in the blood samples obtained from 16 patients with untreated hypertension (UH) and 18 patients with treated hypertension (TH). Fourteen healthy subjects served as normotensive (NT) group. RBC deformability was assessed by using a gravity-driven microfiltration technique. In the UH group, the RBC deformability was found to be significantly lower than those in NT (0.623 +/- 0.06 versus 0.753 +/- 0.078, p < 0.001) and in TH (0.623 +/- 0.06 versus 0.732 +/- 0.055, p < 0.001) groups. The RBC deformability in the TH group was not significantly different than that in the NT group (0.753 +/- 0.078 versus 0.732 +/- 0.055, p > 0.05). Nicotine, in vitro, decreased deformability in the NT (0.668 +/- 0.067 versus 0.753 +/- 0.078, p > 0.0001), UH (0.509 +/- 0.052 versus 0.623 +/- 0.06, p < 0.0001) and TH (0.651 +/- 0.046 versus 0.732 +/- 0.055, p < 0.001) groups. The effect on the UH group was significantly greater than those in the NT (p < 0.0001) and TH (p < 0.0001) groups. These results suggest that nicotine and hypertension independently and cumulatively decrease the RBC deformability and nicotine inhibits the efficacy of antihypertensive treatment on RBC deformability.