The whole study is a prospective observational study of diabetic type 1 and type 2 subjects focusing on the various physical, physiopathological or pharmacological mechanisms that may interfere with the normal response of the cutaneous microcirculation.The study is currently conducted under various parallel groups of patients and control subjects matched on age and sexe. Techniques used for the study are only non-invasive investigations such as iontophoresis with laser doppler flowmetry, clinical and paraclinical non-invasive investigation of peripheral neuropathy, ultrasound imaging of peripheral arteries.