Low transcriptional activity of PON2 in recurrent abortion: A novel therapeutic agent?

Oxidative stress has been reported to be associated with various pregnancy complications and to play key roles in many of them. An inadequate level of antioxidant defense may eventually lead to an early pregnancy loss. There is a lack of information about the roles of the PON2 and PON3 enzymes in the etiology of the cases of unexplained recurrent abortus. The aim of our study is to determine and present the data regarding the roles of these enzymes for the first time.

We measured the transcriptional levels of the PON2 and PON3 enzymes in the curettage materials obtained from the patients with unexplained recurrent abortus (n=25) and compared the results with those measured in the abortus materials from healthy pregnant women (n=50) who had undergone a voluntary abortion. The transcriptional activities of PON2 and PON3 enzymes were measured through quantification of their respective mRNAs by RT-qPCR assay. For each gene, 2^-ΔCt replication values of the control and the patient groups were compared using the Student's t-test, and the p values were calculated thereafter. Fold-changes in the enzyme transcription levels were interpreted as up- or down-regulation.

PON2 mRNA expressions were found to be highly decreased in the patient group (p=0.000002). PON3 transcription, when compared to the healthy pregnant women, was found to be down-regulated in the patient group; however, the difference was not statistically significant (p=0.69).

In this study, we evaluated the expressional regulation of the PON2 and PON3 enzymes in unexplained recurrent abortus. Our results demonstrate for the first time that the expressions of PON2 and PON3 are down-regulated in the abortion specimens of the patients with recurrent miscarriage. Although both enzymes had low expression levels, the decrease in the transcriptional activity of PON2 revealed a high statistical significance. According to these results, it is rational to speculate that PON2 may be a novel therapeutic agent in the management of the cases with unexplained recurrent abortion.