Glowing Spicules and Structural Collapse: A Single-Cell Insight into the Oxidative Aging of Favism Erythrocytes

Erythrocyte aging is a fundamental physiological phenomenon that involves significant structural and nanomechanical alterations of the cells' structure and function. Coupling optical, fluorescence, and Atomic Force Microscopy (AFM), we analyzed morphology, membrane roughness and nanomechanical properties of the very same RBCs arising from favism subjects, measured at different stages of their aging in vitro. We also investigated the evolution and abundance of vesicles arising from the cells over their senescence pathway. This approach combines high-resolution fluorescence imaging with the correlation of membrane topology and biomechanics. This explores the differences between investigation based on statistical morphometric parameters, such as membrane roughness, and those based on the measure of point-dependent nanomechanical properties. Our ultra-morphological study evidences the existence of clear differences in the aging of normal and favism erythrocytes that results in a larger number of cells with abnormal shapes and in a hyper-production of vesicles along the senescence pathway of favism cells. In explaining these differences, we focused on the roles played by the hemoglobin evolution and by the morpho-mechanical properties that are responsible for the skeletal alterations. In particular, our data reported evidence that the two corresponding degradative pathways are coupled and play an important enhancement role in promoting the progression of cell senescence.