Introduction:
The mechanisms underlying the pathogenesis of recurrent pregnancy loss (RPL) and the effective approaches to treat this disease still remain vague and absent. Proteinases of ADAMTS family play important roles in embryonic growth and development. Our previous study suggest a role of ADAMTS13 during pregnancy. Current Study was to determine the expression of ADAMTS13 in human endometrium and its association with RPL.

Material and methods:
The spatiotemporal expression of ADAMTS13 in human endometrium was examined by immunohistochemistry. real-time PCR sand western blot were then employed to determine the mRNA and protein expression levels of ADAMTS13 in human endometrium. Proteolytic cleavage of FRETS-VWF73 were performed to determine the activity of ADAMTS13 in plasma and that secreted by human endometrium. ELISA was carried out to measure plasma VWF antigen.

Results:
We show that proteolytically active ADAMTS13 is expressed in human endometrium throughout the menstrual cycle and pregnancy. The decidual expression levels of mRNA and protein in women with RPL were significantly lower compared with women with uncomplicated pregnancies (P<0.01, P<0.05, respectively). Furthermore, significantly reduced plasma ADAMTS13 activity (median [range] 69.09 [65.2–93.7]% versus 93.62 [88.1–115.6]%, P<0.001) and elevated plasma VWF antigen levels (median [range] of 125.5 [54.2–262.8]% versus 91.9[80.4–138.7]%, P < 0.01) were detected in RPL patients compared with the control group.

Conclusions:
These findings suggest that ADAMTS13 may play a role in embryo implantation and the pathogenesis of recurrent pregnancy loss. Further investigation on ADAMTS13 gene knockout animal models is necessary for understanding the molecular mechanisms of the biological roles of ADAMTS13 during gestation.