AIM: To investigate the expression of serum growth differentiation factor 11(GDF11)and thrombospondin 1(TSP1)in patients with diabetic retinopathy(DR), and discuss their relationship with microvascular injury.

METHODS: Totally 102 DR patients were served as DR group and assigned into non proliferative DR group(NPDR group)and proliferative DR group(PDR group)based on the severity of DR lesions. Meantime, 100 patients with simple diabetes were served as control group. Serum indicators of microvascular injury including vascular endothelial growth factor(VEGF), endothelial cells(ECs), endothelial progenitor cells(EPCs), and levels of GDF11 and TSP1 were measured in each group. Pearson method was used to discuss the correlation between GDF11, TSP1 and microvascular injury indicators. Logistic regression was used to discuss the factors that affected the occurrence of DR. Receiver operating characteristic(ROC)curve was applied to analyze the evaluation value of serum GDF11 and TSP1 for the DR conditions.

RESULTS: For the control group, DR group had lower EPCs and GDF11, and higher VEGF, ECs, and TSP1 levels(all P<0.05). The PDR group had lower GDF11 and higher TSP1 than the NPDR group(all P<0.05). Serum GDF11 was negatively related to VEGF and ECs(r=-0.486, -0.511, all P<0.001), and positively related to EPCs(r=0.475, P<0.001). TSP1 was positively related to VEGF and ECs(r=0.579, 0.594, all P<0.001), and negatively related to EPCs(r=-0.505, P<0.001). Moreover, GDF11 and TSP1 were negatively correlated(r=-0.443, P<0.001). The course of T2DM, VEGF, and TSP1 were risk factors for DR, while GDF11 was a protective factor(all P<0.05). The AUC of GDF11, TSP1, and combined diagnosis for PDR conditions was 0.819, 0.822, and 0.915, respectively. The combined diagnosis was better than single diagnosis(Z_{combination-GDF11}=2.070, P=0.039, Z_{combination-TSP1}=2.274, P=0.023).

CONCLUSION: GDF11 and TSP1 are closely associated with microvascular injury in DR patients and are related to the progression of DR disease, and the combined detection of their serum levels is of clinical value in the assessment of DR disease.