Imagine your red blood cells as tiny, flexible gymnasts maneuvering through an obstacle course of blood vessels. These incredible cells can stretch and bend to fit through the tiniest capillaries, but their elasticity can be affected by various diseases. In a recent study, scientists used atomic force microscopy (AFM) to examine the mechanical properties of red blood cells in patients with Alzheimer’s disease (AD) compared to healthy individuals. By analyzing the viscoelastic response of the cells, they uncovered distinct differences between the two groups. While the traditional analysis didn’t yield significant results, a more detailed examination using the standard linear solid (SLS) model revealed important clues. The altered cell viscosity and elasticity observed in AD patients could potentially serve as valuable blood biomarkers for detecting the disease. To learn more about this groundbreaking research and its implications for early diagnosis of Alzheimer’s disease, dive into the full article!

Red blood cells (RBCs) are characterized by a remarkable elasticity, which allows them to undergo very large deformation when passing through small vessels and capillaries. This extreme deformability is altered in various clinical conditions, suggesting that the analysis of red blood cell (RBC) mechanics has potential applications in the search for non-invasive and cost-effective blood biomarkers. Here, we provide a comparative study of the mechanical response of RBCs in patients with Alzheimer’s disease (AD) and healthy subjects. For this purpose, RBC viscoelastic response was investigated using atomic force microscopy (AFM) in the force spectroscopy mode. Two types of analyses were performed: (i) a conventional analysis of AFM force–distance (FD) curves, which allowed us to retrieve the apparent Young’s modulus, E; and (ii) a more in-depth analysis of time-dependent relaxation curves in the framework of the standard linear solid (SLS) model, which allowed us to estimate cell viscosity and elasticity, independently. Our data demonstrate that, while conventional analysis of AFM FD curves fails in distinguishing the two groups, the mechanical parameters obtained with the SLS model show a very good classification ability. The diagnostic performance of mechanical parameters was assessed using receiving operator characteristic (ROC) curves, showing very large areas under the curves (AUC) for selected biomarkers (AUC > 0.9). Taken all together, the data presented here demonstrate that RBC mechanics are significantly altered in AD, also highlighting the key role played by viscous forces. These RBC abnormalities in AD, which include both a modified elasticity and viscosity, could be considered a potential source of plasmatic biomarkers in the field of liquid biopsy to be used in combination with more established indicators of the pathology.

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