Red blood cells membrane micropolarity as a novel diagnostic indicator of type 1 and type 2 diabetes

Abstract

Classification of the category of diabetes is extremely important for clinicians to diagnose and select the correct treatment plan. Glycosylation, oxidation and other post-translational modifications of membrane and transmembrane proteins, as well as impairment in cholesterol homeostasis, can alter lipid density, packing, and interactions of Red blood cells (RBC) plasma membranes in type 1 and type 2 diabetes, thus varying their membrane micropolarity. This can be estimated, at a submicrometric scale, by determining the membrane relative permittivity, which is the factor by which the electric field between the charges is decreased relative to vacuum. Here, we employed a membrane micropolarity sensitive probe to monitor variations in red blood cells of healthy subjects (n=16) and patients affected by type 1 (T1DM, n=10) and type 2 diabetes mellitus (T2DM, n=24) to provide a cost-effective and supplementary indicator for diabetes classification. We find a less polar membrane microenvironment in T2DM patients, and a more polar membrane microenvironment in T1DM patients compared to control healthy patients. The differences in micropolarity are statistically significant among the three groups (p<0.01). The role of serum cholesterol pool in determining these differences was investigated, and other factors potentially altering the response of the probe were considered in view of developing a clinical assay based on RBC membrane micropolarity. These preliminary data pave the way for the development of an innovative assay which could become a tool for diagnosis and progression monitoring of type 1 and type 2 diabetes.

Graphene Quantum Dots’ Surface Chemistry Modulates the Sensitivity of Glioblastoma Cells to Chemotherapeutics

“…Therefore, we evaluated the alterations of membrane permeability of U87 and cortical neurons after the treatment with GQDs [ 20 ]. For this purpose we labeled cells with Laurdan [ 44 ] that can be used to describe the lipid-phase state in membranes. Membrane fluidity can be measured by several techniques, such as nuclear magnetic resonance [ 45 ], diffusion of membrane molecules [ 46 ], and by fluorescence due to polarity-sensitive probes (Laurdan) [ 44 ].…”

“…For this purpose we labeled cells with Laurdan [ 44 ] that can be used to describe the lipid-phase state in membranes. Membrane fluidity can be measured by several techniques, such as nuclear magnetic resonance [ 45 ], diffusion of membrane molecules [ 46 ], and by fluorescence due to polarity-sensitive probes (Laurdan) [ 44 ]. When compared to other methods, polarity-dependent probes have a high sensitivity for differences in the packing of lipid bilayers in gel/liquid phases.…”

“…Thanks to its dipole moment between the head and the tail, Laurdan is sensitive to the polarity of the environment, thus displaying a red shift of the emission in polar solvents, with respect to non-polar solvents [ 61 ]. This phenomenon is generally defined as solvent relaxation [ 44 ]. Thus, Laurdan is capable of detecting and distinguishing gel phase and liquid phase of cell membrane.…”

Erythrocyte viscoelastic recovery after liver transplantation in a cirrhotic patient affected by spur cell anaemia

“…3C), confirming previous data obtained for spur cells in other pathologies (Cooper et al ., 1977; Balistreri et al ., 1981). The decrease of lipid domains with lower GP values is consistent with an excess of cholesterol, which induces a rigidification of fluid membrane lipid domains at a physiological temperature (Stott et al ., 2008; Leonard et al ., 2018; Bianchetti et al ., 2019). The average GP distribution for the four measured controls (cyan) and the cirrhotic subject (orange) are reported in Figure 3(D).…”

“…Laurdan staining is a widely applicable method for the characterisation of biological and biophysical systems, including many types of cells, antimicrobial compounds, and supported lipid bilayers (Parasassi et al ., 1990; Parasassi et al ., 1991; Stott et al ., 2008; Brewer et al ., 2017; Leonard et al ., 2018; Malacrida & Gratton, 2018; Montis et al ., 2020). One microlitre of Laurdan 2 mM stock solution (Molecular Probes, Inc., Eugene, OR, USA) is added per millilitre of Dulbecco's Modified Eagle's Medium (DMEM) (Bianchetti et al ., 2019). Laurdan emission resulting from the excitation with a 402 nm laser is recorded simultaneously at two different wavelength intervals, 425–475 nm for the first channel and 500–550 nm for the second.…”