Study of the Mechanisms of the Arterial Calcification of the Members Subordinates in the Diabetes (Implication of the System RANK / RANKL / OSTEOPROTEGERINE)

Introduction: Peripheral arterial disease (PAD) is the primary major amputation risk factor in diabetes. The PAD is particularly common among diabetic patients at high cardiovascular risk (20-30% of coronary patients have PAD). The calcification of atherosclerotic plaque and media leg arteries contributes to narrowing of the arterial lumen and exposes the diabetic patient to critical limb ischemia. The receptor RANK (Receptor Activator for Nuclear Factor κ B) and its ligand RANKL form a complex which initially was described as being involved in bone metabolism by activating osteoclasts but the RANK / RANKLigand system could also be involved in the process calcification and arterial obstruction, especially in the lower limbs. Currently there is anti-RANKL antibody used in humans that could possibly slow down this process. But it is necessary to prove the involvement of this system in PAD in diabetic patients at high cardiovascular risk before proposing a therapeutic trial.

Assumptions: the concentration of RANKL could be predictive of calcification of leg arteries in diabetes Main objective: To show that serum RANKL concentrations predict the progression of calcification of the leg arteries in diabetic patients, independently of other cardiovascular risk factors.

Secondary Objectives:

• To show the link between other proteins of bone remodeling, markers of inflammation and glycation, and calcification of leg arteries.
• Measuring the rate of calcification leg arteries.
• Phenotype diabetic patients who have the highest rate of calcification. Primary Outcome: Predictive power of serum RANKL concentration at T0 on the progression of calcification of leg arteries between T0 and T24 months.

Methodology: prospective observational study. The calcium score of leg arteries will be evaluated by a scanner at T0 and 24 months.