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Low-Frequency Submicron Fluctuations of Red Blood Cells in Diabetic Retinopathy
Yair Alster, MD;
Anat Loewenstein, MD;
Shlomo Levin, PhD;
Moshe Lazar, MD;
Rafi Korenstein, PhD
Arch Ophthalmol. 1998;116:1321-1325.
Objective To characterize cell membrane mechanical fluctuations of red blood cells (RBCs) in patients with diabetic retinopathy.
Methods Point dark-field microscopy–based recordings of these local displacements of the cell membrane in human erythrocytes were compared between patients with severe proliferative diabetic retinopathy and healthy controls. The study was performed on discoid RBCs.
Results The average of the maximal displacement amplitude in the diabetic patients was 13.9% ± 1.7% (236 ± 29 nm) compared with 18.7% ± 1.75% (318 ± 30 nm) for the controls (P<.001). The decrease of the RBCs' average displacement amplitude was not correlated with the variation in negative curvature of the central area of discoid cells.
Conclusions Microdisplacements of the cell membrane, which reflect the bending deformability of the RBCs, are directly connected with its efficiency in passing through capillaries narrower than its own diameter. These microdisplacements were significantly reduced in patients with severe diabetic retinopathy because of an increase in viscoelasticity of the cell membrane. Such reduced cell membrane microdisplacements, which reflect lower bending deformability of the RBC, reduce the ability of the cell to enter and pass through small capillaries, increasing tissue ischemia and consequently contributing to the development of diabetic retinopathy.
From the Department of Ophthalmology, Tel Aviv Sourasky Medical Center (Drs Alster, Loewenstein, and Lazar), and the Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University (Drs Levin and Korenstein) Tel Aviv, Israel.
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