OBJECTIVETo study the expression of connective tissue growth factor (CTGF) and its significance in sporadic ascending thoracic aortic aneurysm (AAA), and initially to investigate the mechanisms of pathological remodeling in AAA.

METHODSAAA specimens were taken from 18 patients during elective surgical intervention, and 18 control specimens of ascending aorta were obtained from patients undergoing coronary artery bypass surgery. Specimens were stained with HE and Masson to evaluate the arrangement and aggregation of cells and collagen types I and III; immunohistochemistry staining was performed using antibodies directed against markers of CTGF; real-time PCR analysis was performed to quantify the expression level of CTGF and collagen types I and III.

RESULTSPathological results show degradation of elastin and hyperplasia of collagen fibers as well as disordered arrangement of smooth muscle cells in AAA. When compared with controls, protein levels of CTGF were significantly increased [(44 ± 4)% vs. (33 ± 5)%, P < 0.01]. Similar patterns were shown in mRNA levels of CTGF (P < 0.01). Using real-time PCR method, elevated levels (relative expression ratio of mRNA: 10.54/3.8 and 1.79/1.19, respectively; P < 0.01, both) of collagen types I and III were observed. CTGF expression had a correlation with both collagen fibers and aortic aneurysm diameter (r = 0.784, P < 0.01; r = 0.793, P < 0.01).

CONCLUSIONSThese results indicate increased expression of aortic collagen types I and III as well as CTGF in AAA specimens, which is likely to be responsible for the aortic wall pathological remodeling. The expression of CTGF was positively correlated with the aortic diameter. As a cytokines factor can stimulate collagen synthesis, CTGF may be involved in the pathogenesis and progression of AAA.