Alpha thalassemia protects sickle cell anemia patients from macro-albuminuria through its effects on red blood cell rheological properties

Abstract

While chronic hemolysis has been suspected to be involved in the development of glomerulopathy in patients with sickle cell anemia (SCA), no study focused on the implications of blood rheology. Ninety-six adults with SCA at steady state were included in the present cross-sectional study. Three categories were defined: normo-albuminuria (NORMO, n = 41), micro-albuminuria (MICRO, n = 23) and macro-albuminuria (MACRO, n = 32). Blood was sampled to measure hematological and hemorheological parameters, and genomic DNA extraction was performed to detect the presence of α-thalassemia. The prevalence of α-thalassemia was lower in the MACRO group compared with the two other groups. Anemia was more severe in the MACRO compared with the NORMO group leading the former group to exhibit decreased blood viscosity. Red blood cell deformability was lower and red blood cell aggregates strength was greater in the MACRO compared to the two other groups, and this was directly attributed to the lower frequency of α-thalassemia in the former group. Our results show the protective role of α-thalassemia against the development of sickle cell glomerulopathy, and strongly suggest that this protection is mediated through the decrease of anemia, the increase of RBC deformability and the lowering of the RBC aggregates strength.

Keywords: Sickle cell anemia; glomerulopathy; hemolysis; hemorheology.