Endocrine Abstracts

Background: red blood cells (RBC) membrane fluidity in patients with type 2 diabetes mellitus (T2DM) can be influenced by various factors like oxidative stress, aging, glycosylation, lipid homeostasis and exposure to nutrients.

Objective: To analyze RBC membrane fluidity in patients with long-duration T2DM (more than 10 years), looking for any differences between patients without and with macroangiopathy (vascular diabetic foot).

Methods: 27 patients with long-lasting T2DM, 15 affected by vascular diabetic foot (DF group) and 12 without complications (DM group), and 10 healthy subjects have been enrolled. We have used confocal microscopy to analyze images of RBC labeled by Laurdan, a fluorescent probe which varies its fluorescence emission based on membrane polarity (490 nm for the fluid-crystalline state and 440 nm for the gel-like). Membrane fluidity has been measured as GP index, ‘generalized polarization’, (GP = (I440 nm – I490 nm) / (I440 nm +I490 nm)), with values between −1 and +1, where GP values tending to −1 are indicative of higher membrane fluidity.

Results: DM and DF have been resulted comparable for age, body mass index, disease duration, glycated haemoglobin, total cholesterol, HDL, LDL and triglycerides. GP index has been significantly lower in DF (mean GP 0.501, S.D. 0.026) than in DM (mean GP 0.519, S.D. 0.007) (P-value 0.04), with a higher value in healthy subjects (mean GP 0.534, S.D. 0.018) compared both to DM (P-value 0.03) and to DF (P-value 0.008).

Conclusions: RBC membrane has been resulted more fluid in diabetic patients with macroangiopathy than in patients without complications, despite a similar duration of disease. Variations in membrane fluidity may underlie the development of macrovascular complications due to possible alterations in gas exchange and in the expression of membrane receptors; membrane fluidity analysis could be useful in to the future to identify patients at risk of developing chronic complications of diabetes.