Abstract: Objective To investigate the expression of von Willebrand factor cleaving protease (ADAMTS13) in peripheral blood of patients with proliferative type 2 diabetic retinopathy and its value in evaluating the effect of atorvastatin intervention. 
Methods A total of 118 patients with proliferative diabetic retinopathy (PDR) in Haian People′s Hospital were selected as the PDR group, and all the patients had type 2 diabetes mellitus (T2DM). All of them were tested for the activity of plasma ADAMTS13. All PDR patients were divided into control group and observation group according to the random number table method, with 59 patients in each group. The control group was given conventional hypoglycemic therapy, while the observation group was given atorvastatin on the basis of basic hypoglycemic therapy. The blood glucose, blood lipid and plasma ADAMTS13 and pigment epithelium-derived factor (PEDF) activities of PDR patients were detected at 3 months after continuous administration. 
Results The plasma ADAMTS13 activity in the PDR group was significantly lower than clinical normal value. After treatment, the blood glucose levels and glycated hemoglobin levels in both groups were lower than those before treatment (P＜0.05), while the glycated hemoglobin levels in the observation group were lower than those in the control group (P＜0.05). After treatment, the levels of TG, TC, and LDL-C in both groups were lower than those before treatment, and lower in the observation group than in the control group (P＜0.05). After treatment, the plasma ADAMTS13 activity increased and plasma PEDF activity decreased in both groups. The plasma ADAMTS13 and PEDF activities in the observation group were higher than those in the control group (P＜0.05). Pearson correlation analysis results showed that ADAMTS13 was negatively correlated with PEDF, blood glucose, glycated hemoglobin, TG, TC, and LDL-C (r=-0.451, -0.573, -0.612, -0.548, -0.650, -0.504, P＜0.001), while baseline ADAMTS13 was positively correlated with the degree of improvement after treatment (r=0.572, P＜0.001). 
Conclusion Plasma ADAMTS13 expression in patients with T2DM and PDR is down-regulated. Atorvastatin can effectively control blood glucose and blood lipids in patients with T2DM and PDR, and promote the expression of ADAMTS13 in patients with PDR. ADAMTS13 expression can reflect the therapeutic effect of atorvastatin. 

Key words: diabetes mellitus, type 2, proliferative diabetic retinopathy, von Willebrand factor cleaving protease