Researchers at Karolinska Institutet have identified the guinea pig as a promising model for studying the early development of human embryos. A new study shows that guinea pig embryos share many important characteristics with human embryos, which could open up new research opportunities in fertility and stem cell biology.

Studying the early development of human embryos is challenging due to ethical constraints and technical difficulties. Therefore, animal models are often used to understand the biological processes that govern embryo development before it implants in the uterus.

In a new study, researchers at Karolinska Institutet, in collaboration with Université de Montréal, have investigated how guinea pigs can serve as an alternative model for studying this critical period.

Similarities with humans

By analysing guinea pig embryos using advanced single-cell RNA sequencing, the researchers mapped gene expression patterns during embryo development. The results show that the preimplantation development of guinea pigs, i.e., the time before the embryo attaches to the uterine wall, is surprisingly similar to that of humans.

They also identified that embryo attachment resembles that of humans and appears to be regulated by retinoic acids and possibly an important nuclear receptor NR2F2. This is promising because, with this model, we can increase our understanding of why implantation failure often occurs in humans and potentially develop treatments to prevent this.

“Guinea pig embryos undergo a developmental process that largely mirrors that of humans, both in terms of the timing of cell specialization and the genes that control these changes,” says Sophie Petropoulos, a researcher at the Department of Clinical Science, Intervention and Technology at Karolinska Institutet and one of the study’s lead authors.

The researchers identified several conserved pathways, including the Hippo, MEK-ERK, and JAK-STAT systems, which control the differentiation of embryonic cells in both guinea pigs and humans. Additionally, analyses showed that key genes for the development of the embryo’s first cell layers are expressed similarly in both species.

A new model for embryo research

Unlike other common laboratory animals, such as mice, guinea pigs have a preimplantation development that is more comparable to that of humans in terms of timing and the molecular circuitries that govern blastocyst formation. Additionally, both guinea pigs and humans undergo a type of implantation where the embryo penetrates the uterine lining, which differs from mice and other rodents.

Another important aspect is that guinea pigs have a placental structure similar to that of humans. This allows researchers to use guinea pigs to investigate how early environmental changes, such as exposure to various chemicals or drugs, can affect embryo development and future health.

“Guinea pigs can become a valuable model for understanding how early disturbances in embryonic development can affect health later in life. Since guinea pig development mirrors that of humans better than many other animal models, we can gain more reliable insights into how the embryo’s environment affects its future,” says Sophie Petropoulos.

The researchers hope that this new knowledge can contribute to better methods in assisted reproduction and an increased understanding of development-related diseases. With the guinea pig as a model, future research can also provide important information about stem cell biology and regenerative medicine.

Source – Karolinska Institutet