The diagnosis and treatment of ectopic pregnancies, which result in about 70 maternal deaths annually in the United States, could be improved and made safer by nanotechnology.
Image Credit: Dragana Gordic/Shutterstock.com
Leslie Myatt, Ph.D., of Oregon Health & Science University, and Olena Taratula, Ph.D., of Oregon State University, have collaborated on research that demonstrates the effectiveness of a method involving nanoparticles, photoacoustic imaging, and infrared light in mice. The study was published in the journal Small.
Too many people become seriously ill and even die because the best-available methods to detect and treat ectopic pregnancies simply are not good enough. I hope research like this will create better options for those who unfortunately experience an ectopic pregnancy.
Leslie Myatt, Ph.D., Professor, Obstetrics and Gynecology, Oregon Health & Science University
Ectopic pregnancies, in which an embryo is implanted in a fallopian tube or somewhere else outside the uterus and cannot develop normally, account for 1 – 2% of all pregnancies. If untreated, an abnormally implanted embryo can invade nearby blood vessels and result in internal bleeding.
This serious pregnancy complication is characterized by excruciating pelvic pain and occasionally bleeding. Treatment for ectopic pregnancies is necessary to avoid serious illness, decreased fertility, and even the mother’s death.
Currently, a pelvic ultrasound examination is used to identify this serious pregnancy complication. However, due to limitations in imaging techniques, this method could fail to detect up to 40% of ectopic pregnancies.
To lessen the uncertainty that many people experience in the early stages of pregnancy when the complication is a concern, better diagnostic techniques are required.
The drug methotrexate, which prevents rapidly dividing cells from multiplying, is currently used to treat the majority of ectopic pregnancies, but it is also known to have serious side effects.
Additionally, about 10% of ectopic pregnancies are not terminated by the drug, necessitating further treatment or surgery. More severe conditions could necessitate immediate surgery and result in significant blood loss.
When Myatt learned that an OHSU colleague was working with OSU to create a potential nanotechnology-based treatment for endometriosis, a painful condition that results in dangerous lesions in the ovaries and fallopian tubes, he was intrigued.
Myatt is a scientist who studies the placenta and other pregnancy-related organs. Research on mice has demonstrated that lesions can be successfully removed using technology without surgery.
Myatt proposed the use of nanoparticles to identify and treat ectopic pregnancies to Taratula, a nanotechnology researcher at the OSU College of Pharmacy. They collaborated with other OHSU and OSU employees to create a fluorescent nanoparticle material that produces heat when exposed to infrared light.
They combined their nanoparticles with a photoacoustic imaging system, which picks up sound waves produced when tissue is struck by pulsed lasers.
They injected a non-toxic solution containing nanoparticles and a light-responsive substance into pregnant mice to see if their novel concept might help with ectopic pregnancy detection and treatment.
The solution was carried by the blood until it gathered on the placenta’s surface. After that, the researchers set up their imaging apparatus outside the mouse’s body and pointed it at its uterus.
The resulting images made it abundantly clear that nanoparticles were illuminating the placenta’s surface. This gave rise to the idea that the technology might be used to determine whether a placenta is developing normally or, in the case of a risky ectopic pregnancy, whether it should not be.
Another function of the nanoparticles was to heat up when exposed to concentrated near-infrared light. They discovered that placental tissue became non-viable when nanoparticles covering its surface became warm while testing their technology in lab mice.
The team speculates that their technology might provide a non-invasive and efficient means of treating ectopic pregnancies as a result.
It is significant to note that the researchers did not record nanoparticles traversing placental tissue. This implies that should their novel imaging approach show a placenta is growing safely, and pregnancy is not ectopic, the non-toxic solution could stay in place without harm.
The research team is still studying their methodology in mice, and they intend to study it in nonhuman primates as well, which are more closely related to humans.
The team is also modifying the technology by including molecules on the exterior of the nanoparticles in an effort to more precisely target the placenta using fewer nanoparticles, thanks to assistance from the OHSU Center for Women’s Health Circle of Giving.
The National Cancer Institute (grants R01CA237569 and R37CA234006), the National Center for Advancing Translational Sciences (grants R03 TR004020-01 and KL2 TR002370), Oregon State University, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (grant R01HD101450), and Oregon Health & Science University provided funding for this study.
Moses, A. S., et al. (2022) Nano-Theranostic Modality for Visualization of the Placenta and Photo-Hyperthermia for Potential Management of Ectopic Pregnancy. Small. doi:10.1002/smll.202202343.