Endocrine Abstracts

Background: Cell membrane fluidity of erythrocytes in patients with type 2 diabetes can be influenced by glycosylation processes, changes in lipid homeostasis and oxidative stress.

Objectives: We have measured red blood cell membrane fluidity looking for differences between healthy people and diabetic subjects and also between diabetic patients affected by macroangiopathy (vascular diabetic foot) and not.

Methods: We have enrolled 32 subjects: 8 healthy controls (group G0), 9 diabetic patients without macroangiopathy (G1) and 15 with macroangiopathy (G2). We have used an inverted confocal microscope to analyze images of erythrocytes labeled by the Laurdan probe, that varies its fluorescence emission based on the polarity of the membrane, discriminating between fluid-crystalline state (emission spectrum at 490 nm) and state gel-like (less fluid, emission spectrum at 440 nm). Results of fluidity analysis have been calculated as GP index, “generalized polarization” (G P=(I440 nm - I490 nm) / (I440 nm + I490 nm)), that assumes values between -1 and +1, where lower values tending to -1 indicate higher fluidity.

Results: diabetic patients have an higher GP index compared to healthy subjects (p<0.01). GP mean value grows among the three groups: in G0 is 0.600956 (±0.005161), in G1 0.626324 (±0.015676) and in G2 0.641015 (±0.008644), with a GP index significantly higher in G2 than in G0 (p<0.01). We have found a direct correlation between GP and triglyceridemia mean value and an inverse correlation between GP mean value and HDL cholesterol mean value.

Conclusions: Diabetic patients, compared to healthy subjects, have a less fluid cell membrane fluidity with a further reduction in patients affected by macroangiopathy. These results suggest the utility to integrate analysis of membrane fluidity with laboratory exams (like HbA1c) for an early identification of macroangiopathic complications.