New role discovered for macrophages

Research from the University of Adelaide’s Robinson Institute has shown that macrophages play a pivotal role in conception and establishing pregnancy through the production of progesterone.

“Previous research has demonstrated that macrophages are prevalent in reproductive tissues, but this is the first time that their absolute necessity for pregnancy has been demonstrated," said Professor Sarah Robertson, from the Robinson Institute who led the team that made the discovery.

“Macrophages organise the development of blood vessel networks in the ovary required for production of progesterone, which is the major hormone for initiating pregnancy.”

Progesterone is also essential for embryo implantation. The researchers found that insufficient numbers of macrophages led to a reduced production of progesterone, which resulted in embryos implanting poorly or not at all, and could manifest later as miscarriage.

“The contribution of macrophages to the healthy vascular structure of the corpus luteum, which must develop rapidly in a matter of days to produce high levels of progesterone, was a surprise,” Professor Robertson said.

However, the laboratory studies showed that treatment with progesterone could reverse the effects caused by reduced levels of macrophages.

But ultimately the researchers hope to improve fertility by more natural means.

“If macrophages are shown to play the same role in women as we’ve seen in our laboratory studies, this gives us potential new avenues for targeting them with lifestyle and nutritional intervention, improving fertility by advancing the quality of the conception environment.”

This research was published online by the Journal of Clinical Investigation.