A recent study conducted on monkeys by biologists from the Chinese Academy of Sciences has found that 91 changes in organs occur during pregnancy. The study was done on crab-eating macaque (Macaca fascicularis) also called ‘cynomolgus monkeys,’ which are one of the primates that are closely related to humans and are usually used to study human behaviours in experiments.
The researchers created a map that documents the changes that happen within the body during pregnancy, predominantly looking at the body’s relationships in the metabolic pathways. The study named, ‘A multi-tissue metabolome atlas of primate pregnancy’ was published in Cell on February 1, 2024.
Twelve monkeys bred in captivity were the subject of the study, the monkeys were separated into four subgroups of three: non-pregnant, early pregnancy, mid-pregnancy and late pregnancy. Each monkey had samples of blood serum collected, and then over a dozen tissue samples from different organs in their body were also collected.
In total, there were over 270 tissue samples collected. This study intended to look further into the bodily changes during pregnancy, a relatively under researched topic and it could perhaps lead to a better understanding of issues like preeclampsia, gestational diabetes and miscarriages within pregnancies. Liquid chromatography-mass spectrometry was used to dissect the samples.
This study found that in each tissue sample taken, there were full sets of ‘metabolomes’ and there were eight core pathways that were associated with various maternal tissues. It was found that as the pregnancy progressed, there was a decline in the metabolic coupling between tissues.
Using the non-pregnant monkeys as a reference for the interaction of metabolic pathways before pregnancy, the researchers concluded that skeletal muscle metabolites were correlated with the heart, uterus, adrenal gland and spinal cord. During the first trimester, the uterus’ metabolic coupling with both the heart and skeletal muscles declines as the uterus couples with the placenta instead.
In the second trimester, once the placenta is fully formed, it sends metabolites back to the heart, as well as the liver and ovaries. Surprisingly, at this point in pregnancy, the uterus starts up a metabolic exchange with the scalp tissue. Finally, the third trimester sees an exchange between the spinal cord and skeletal muscles.
Although it was unclear why these changes happened, it was verified by the samples of 32 pregnant human blood serum as well as human cell models. Moreover, it was found that corticosterone deficiencies induced inflammation associated with preeclampsia.
Shyh-Chang Ng, who co-authored the study, says that “Corticosterone is a key steroid in human pregnancy” that is “underappreciated” within research. Even though macaques have shorter pregnancies than humans (almost 20 weeks less) they still serve as reliable sources in this case. The biologists a part of this research study hope that their findings, “will help spur further research” into how pregnancy changes the body.
Edited by Chloe Mansola
Image ‘Macaque monkey wood’ by Rawpixel licenced by CC0 1.0