University of Wisconsin researchers and collaborators recently published a feasibility study that focuses on limiting fetal growth restriction in nonhuman primates through nanoparticle injections of IGF1, an insulin-like growth factor, according to the study published in PubMed.
A feasibility study is designed to support the viability of an idea. Fetal growth restriction refers to when a fetus does not grow at the expected rate.
The study is designed to help understand how the placenta works during pregnancy and how IGF1 injections can aid in fetal growth, University of Florida researcher Helen Jones said. Problems with fetal growth can lead to an early delivery.
The purpose of this study was to continue similar research that had been done on rats and guinea pigs, which had promising results. The reproductive environment of guinea pigs is quite translational to humans in reflecting how FGR affects a pregnancy whereas macaque monkeys help to define what the safety and delivery would look like when applied to humans.
“We are trying to actually treat the placenta itself, to improve that overall environment and then be able to improve the growth of the fetus,” Jones said.
The research done is designed to show the possibility of using similar injections into human placentas after FGR is detected, according to the study.
Reducing FGR promotes a decrease in infant mortality, limiting premature and underdeveloped births. This can also increase longevity, as 80% of adult deaths worldwide are from non-communicable diseases, which are seen more in adults who were born prematurely, according to the study.
“The occurrences of being born too small or too soon can be anywhere from sort of 5-7% in the developed world and up to 20% in the undeveloped world,” Jones said. “And worldwide, potentially, this could impact quite a significant proportion of humans.”
In this particular study, six nonhuman primates were studied — five rhesus macaque and one cynomolgus macaque monkey. Since one of the rhesus macaques conceived two fetuses, there were a total of seven fetal environments.
The number of individuals is a limiting factor when studying nonhuman primates. Because this was a feasibility study based on long-standing research, the number of trials was not as imperative to achieve convincing results, according to research assistant professor at UW Jenna Schmidt.
“In any non-human primate studies, we are not able to recruit a really large number of animals to study, which is also why the guinea pig has an advantage too, you have more flexibility in recruiting a larger number of animals,” Schmidt said. “So this was a feasibility study, so we wanted to just see that the delivery mechanism was working.”
Another factor the researchers had to consider was the lack of a traditional control group. They used baseline values taken prior to the treatment as a comparison, Schmidt said.
This study’s success in showing just how safe and effective nanoparticle injections of IGF1 into nonhuman placentas are in promoting fetal growth, creating feasibility, has allowed for additional studies. Jones and Schmidt are currently working on two studies, one with guinea pigs and one with nonhuman primates.
“In our current studies, we can build in additional control groups where animals are not treated with the nanoparticle, and then also treated with a particle that does not have the extra same IGF1 treatment in it,” Schmidt said.
The current study on guinea pigs involves allowing the fetuses to develop and eventually to be born, allowing both mom and offspring to be studied. Jones said this method will allow for understanding and assessment of the long-term impact of the injection.
Scientific studies conducted on animals, regardless of researchers’ adherence to regulations and commitment to ethical practices, are often subject to scrutiny.
“With any animal research, there are a lot of regulations, there’s a lot of oversight, and so we set in place all the necessary protocols and approvals from our institution and those we follow from outside of our institution,” Schmidt said. “You can see all the necessary protocols on the UW site for Animal in Research and Teaching.”
This feasibility study allows for expanding research that could one day save the lives of premature and underdeveloped fetuses. The continuation of research of this kind could also potentially limit non-transmittable diseases, as fewer newborns could suffer from FRG, according to the study.
Helping future mothers who have been diagnosed with FRG is within the clear implications of future treatments aided by these studies. Because of the nature of FRG and its impacts on babies born of it, many ways of limiting it before birth creates a healthier population even as the babies age.
“There is a lot of research that demonstrates that if you are born too small or too soon, depending on how you choose to live your life, you are at much higher risk of non-transmissible disease like cardiovascular disease, the obesity released metabolic disease as well,” Jones said.
Editor’s Note: This article has been updated to correct Helen Jones’ title, who is a researcher at the University of Florida.