Relationship between elevated circulating thrombospondin‐1 levels and vascular complications in diabetes mellitus

Abstract Aims/Introduction Thrombospondin‐1 (TSP‐1) participates in a series of physiological and pathological processes by binding to various receptors regulating cell proliferation, adhesion and apoptosis. Elevated circulating TSP‐1 is linked with diabetic vascular complications (DVC). This study aimed to determine the relationship between circulating TSP‐1 levels and DVC. Materials and Methods A comprehensive search of PubMed, Embase, Web of Science and CNKI databases was carried out. A meta‐analysis was carried out to compare circulating TSP‐1 levels between diabetes patients without vascular complications (DNVC), diabetes patients with DVC and non‐diabetes patients. The correlation between TSP‐1 and metabolic parameters was also analyzed. Subgroup analysis was carried out according to complication type, defined as diabetic retinopathy, diabetic nephropathy and diabetic cardiovascular disease (DCVD). Results A total of eight studies were included. Compared with non‐diabetes patients, diabetic patients, including DNVC and DVC, had significantly higher circulating TSP‐1 levels (standardized mean difference [SMD] 2.660, 95% CI 1.17–4.145, P = 0.000). DNVC had significantly higher circulating TSP‐1 levels than non‐diabetes patients (SMD 3.613, 95% CI 1.607–5.619, P = 0.000). DVC had significantly higher TSP‐1 levels than DNVC (SMD 0.568, 95% CI 0.100–1.036, P = 0.017). TSP‐1 was significantly positively correlated with fasting plasma glucose (overall Fisher's z = 0.696, 95% CI 0.559–0.833) and HbA1c (overall Fisher's z = 0.849, 95% CI 0.776–0.923). Conclusions Elevated circulating TSP‐1 levels are closely related to DVC, especially in diabetic nephropathy and diabetic cardiovascular disease. Circulating TSP‐1 detection might be helpful in the timely diagnosis and treatment of DVC.