The system of osteoprotegrin (OPG)/ligand of NF-kB receptor activator (RANKL) in patients with diabetes mellitus, mediacalcinosis and obliteratingatherosclerosis of lower leg arteries

Aim.
To study the OPG/RANKL system in patients with diabetes mellitus, mediacalcinosis and obliterating atherosclerosis of lower leg arteries.
Materials and methods.
The study enrolled 70 patients including 20 with manifest diabetic neuropathy (DN) and mediacalcinosis of lower leg arteries(group 1). 29 patients with diabetes mellitus (DM) and clinical manifestations of obliterating atherosclerosis of lower leg arteries comprised group 2. Thecontrol group 3 consisted of 30 subjects without disturbances of carbohydrate metabolism. Immunoassays with Alkphase-B (Metra biosystems, USA),Osteoprotegrin (Biomedica, Austria), and sRANKL(Biomedica, Austria) kits were used to detect serum markers of bone formation (alkaline phosphatase(AP), OPG, and RANKL respectively). The patients underwent examination by digital X-ray of affected joints in frontal and lateral projections using anAxiom Iconos R 200 apparatus (Siemens, Germany). Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (Expert 1188,Lunar, USA). Ultrasound duplex scanning of lower leg arteries was performed with Sonoc-5500 (Agilent, USA).
Results.
OPG levels in diabetic patients were significantly higher than in controls (p<0.0001). In group 1, they negatively correlated with RANKL (r = 0.68;p<0.001). Total cholesterol (TC) in diabetic patients was higher than in controls (p<0.05). In the former, TH and TG levels correlated with OPG concentration(r = 0.3; p<0.0003 and r = 0.2; p<0.001 respectively). Inverse correlation between BMD and OPG (r= -0.61; p<0.002) was documented in group 1.AP in diabetic patients correlated with OPG (r = 0.1; p<0.01) and RANKL (r = 0.21; p<0.01).
Conclusion.
The OPG/RANKL system participates in the development of mediacalcinosis and calcification of arterial intima in the lower extremities.

osteoprotegrin, RANKL, mediacalcinosis, obliterating atherosclerosis

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