A team of researchers at The University of Manchester and Manchester University NHS Foundation Trust conducted an in vitro research which exhibited a new way human embryos communicate with their mother-to-be just after six days of its development. The study also put light on the fact that the embryos could detect foreign cells in their environment including pathogens. Early human embryos are highly sensitive to their local environment but before this study, relatively less was known about how they detect and respond to specific environment cues.
This study has discovered a signalling system which is generated by the embryo which allows communication with mother in a new way wherein it was found that when foreign cells are detected by the embryos’ special proteins called Toll Like Receptors(TLRs), cytokines (IL8) are produced which typically plays a role in the body’s immune system by engaging neutrophils to the inflammation site. The team examined the behaviour of the embryo throughout the fifth and sixth days of the embryos’ development wherein it is free-living in the female body before implanting into the uterus lining.
It is already known that embryos communicate with mothers when they begin to implant but we do not know why this above-mentioned new signalling happens. Perhaps this presence of TLRs in the fallopian tube and vagina is an additional way of signalling an inflammatory response to the maternal tract in response to pathogens or to modulate the implantation process and the initiation of pregnancy.
The team used a literature search of published data to analyse the expression of TLRs and related genes in human embryos. Then they cultured 25 days old human embryos in the presence of poly (I:C) and flagellin which attach to the toll-like receptors TLR3 and TLR5. EThe team only investigated TLR 3 and 5 and on the sixth day, they measured gene expression and cytokine production to compare the results with the controls.
The data also reveals that there is a balance between suppression and stimulation of the innate immunity response in embryos. That may reflect the need for embryo survival in the presence of benign foreign cells versus the need for maternal tract to respond to infection. This groundbreaking research may help to understand fertility issues, helping people who struggle to achieve natural conception and even enhancing IVF methods. The research is published in the Journal Human Reproduction Today. Still further investigations need to be done to determine whether the TLR stimulation response is effective during the embryonic journey in the fallopian tube.