Aging Injury Impairs Structural Properties and Cell Signaling in Human Red Blood Cells; Acai Berry Is a Keystone

Red blood cell (RBC) deformability is the ability of cells to modulate their shape to ensure transit through narrow capillaries of the microcirculation. A loss of deformability can occur in several pathological conditions, during natural RBC aging through an increase in membrane protein phosphorylation, and/or through the structural rearrangements of cytoskeletal proteins due to oxidative conditions, with a key role played by band 3. Due to the close relationship between aging and oxidative stress, flavonoid-rich foods are good candidates to counteract age-related alterations. This study aims to verify the beneficial role of Acai extract in a D-Galactose (D-Gal)-induced model of aging in human RBCs. To this end, band 3 phosphorylation and structural rearrangements in membrane cytoskeleton-associated proteins, namely spectrin, ankyrin, and/or protein 4.1, are analyzed in RBCs treated with 100 mM D-Gal for 24 h, with or without pre-incubation with 10 mu g/mL Acai extract for 1 h. Furthermore, RBC deformability is also measured. Tyrosine phosphorylation of band 3, membrane cytoskeleton-associated proteins, and RBC deformability (elongation index) are analyzed using western blotting analysis, FACScan flow cytometry, and ektacytometry, respectively. The present data show that: (i) Acai berry extract restores the increase in band 3 tyrosine phosphorylation and Syk kinase levels after exposure to 100 mM D-Gal treatment; and (ii) Acai berry extract partially restores alterations in the distribution of spectrin, ankyrin, and protein 4.1. Interestingly, the significant decrease in membrane RBC deformability associated with D-Gal treatment is alleviated by pre-treatment with Acai extract. These findings further contribute to clarify mechanisms of natural aging in human RBCs, and propose flavonoid substances as potential natural antioxidants for the treatment and/or prevention of oxidative-stress-related disease risk.

Automated summary

The study aims to investigate the effects of Acai extract in a model of aging in human red blood cells. The results show that Acai extract can restore the phosphorylation of membrane proteins and partially reverse the structural changes in cytoskeletal proteins. Additionally, Acai extract can improve the deformability of red blood cell membranes. These findings are important for understanding the mechanisms of aging in human red blood cells and suggest that flavonoid substances can be used as natural antioxidants for the treatment and prevention of oxidative-stress-related diseases.