ADAMTS13 and von Willebrand factor concentrations in patients with diabetes mellitus.

The von Willebrand factor (VWF) is elevated in patients with diabetes mellitus and degraded by a metalloprotease, ADAMTS13. We hypothesized that this elevation is due to a decreased function of ADAMTS13. Thus, we investigated ADAMTS13 in patients with diabetes mellitus without and with peripheral artery occlusive disease (PAOD). When treating the latter group with dalteparin, VWF is reported to increase significantly, and we therefore measured ADAMTS13 also in these patients. VWF antigen and ADAMTS13 antigen and activity concentrations were measured in patients with diabetes mellitus but without PAOD (diabetes mellitus; n = 23) and with diabetes mellitus and PAOD (diabetes mellitus + PAOD; n = 65) before and after treatment with dalteparin or placebo. In the diabetes mellitus group, concentration of VWF antigen was significantly higher, whereas that of ADAMTS13 activity was significantly lower than in the healthy controls. In the diabetes mellitus along with PAOD group, VWF antigen was significantly higher, but ADAMTS13 antigen or activity did not differ significantly from those of healthy controls. The ADAMTS13 activity/antigen ratio was lower than in controls only in the diabetes mellitus patient group. VWF antigen increased significantly during dalteraprin treatment, whereas ADAMTS13 activity and antigen remained unchanged. Only patients with diabetes mellitus had significantly lower concentrations of ADAMTS13 activity in plasma than controls, although the diabetes mellitus along with PAOD had a more pronounced VWF antigen elevation than diabetes mellitus patients, illustrating a possible link between ADAMTS13 and microangiopathy in diabetes mellitus patients. The increase in VWF antigen concentration during treatment with dalteparin does not seem to be due to changes in ADAMTS13.