Expression and localization of collectins in feto-maternal tissues of human first trimester spontaneous abortion and abortion prone mouse model

• SP-A and SP-D transcripts are differentially expressed in feto-maternal tissues of spontaneous abortion.
• SP-A and SP-D levels are increased in placental tissues of viable embryos from abortion prone mouse model.

Dysregulation of immune response at the feto-maternal interface during first trimester of pregnancy is one of the leading causes of spontaneous abortion. Previously, we reported differential expression of collectins, soluble pattern recognition molecules involved in immunoregulation, in placental and decidual tissues during spontaneous labor. In the present pilot study, the expression of collectins was analyzed in the inflamed human gestational tissues of spontaneous abortion (‘SA’) and in 13.5 dpc placental tissues from resorption survived embryos of murine model (CBA/J X DBA/2J). Transcripts of SP-A were significantly down-regulated and SP-D were significantly up-regulated in placental and decidual tissues of ‘SA’ group compared to that of ‘normal’ group. Immunostaining for SP-D and MBL proteins was positive in placental and decidual tissues. However, levels of SP-D and MBL proteins were not significantly altered in placental as well as in decidual tissues of ‘SA’ group in comparison to the ‘normal’ group. Placental tissues of viable embryos from the abortion prone mouse model showed significantly enhanced expression of mSP-A and mSP-D transcripts at 13.5 day post coitus (dpc) and 14.5 dpc compared to the control group (CBA/J X Balb/c). Mouse collectins were localized in placental tissues (13.5 dpc), with increased staining in murine model compared to control. Human and murine data together indicate that SP-A, SP-D and MBL are synthesised in early gestational tissues, and may contribute to regulation of immune response at the feto-maternal interface during pregnancy.