Increased deformability of red blood cells is associated with a deletion polymorphism of the angiotensin-converting enzyme gene.

Angiotensin-converting enzyme (ACE) plays important roles in the renin-angiotensin system. ACE converts angiotensin I to angiotensin II and also inactivates bradykinin, thereby modulating the vascular tone. A polymorphism of the ACE gene, located on chromosome 17, has been found in intron 16, and is characterized by the presence (insertion [I]) or absence (deletion [D]) of a 287-base-pair Alu repeat. Individuals with the D allele of the ACE gene have higher ACE levels and are at higher risk of cardiovascular events. We aimed to investigate the possible relationship between the I/D polymorphism of the ACE gene and hemorheological parameters, including red blood cell (RBC) deformability. The study was performed on 28 healthy young volunteers (13 women and 15 men, mean age 24 +/- 2). The prevalence of the I and D alleles was 30.4% and 69.6%, respectively. The I/I genotype (II) was found in 21.4%, I/D genotype (ID) in 17.9%, and D/D genotype (DD) in 60.7% of the subjects tested. No significant relationship between ACE I/D polymorphism and RBC aggregation or whole blood and plasma viscosity was observed. In contrast, RBC deformability was significantly increased in the subjects with the DD genotype compared with the II (p < 0.05) or the ID (p < 0.01) genotype, and in the subjects with the D allele compared with the I allele (p < 0.01). We suggest that RBC deformability of individuals with the D allele, who have higher risk for cardiovascular pathologies, may have been increased by a compensatory mechanism