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Biochemists test gold-bearing nanoparticles as potential new therapy
Endometriosis is a painful, common condition affecting women worldwide, but treatment and diagnosis options are scarce. A new University of Mississippi-led study may have found an answer to both problems.
Early results from a study published in Communications Chemistry show that gold-laced nanoparticles can hitchhike on white blood cells. By using those cells as a delivery vehicle, the team hopes to identify and treat endometriosis without repeated surgeries.
“Lots of women go through their lives being in enormous amounts of pain and thinking that it’s normal, and it’s not normal,” said Eden Tanner, assistant professor of chemistry and biochemistry, who authored the study with a team of Ole Miss researchers.
“Endometriosis is difficult to diagnose and even more difficult to treat, but these people deserve health care.”
Endometriosis effects around 1 in 10 women worldwide. It occurs when uterine lining tissues, like those produced and shed during each menstrual cycle, form outside the uterus. This causes inflammation, bloating, and pain, and is the leading cause of infertility in women worldwide.
During each menstrual cycle, the cells multiply as they would if they were inside the uterus but are not shed. This means that for a person with endometriosis, the problem gets worse each month.
“This is a very painful and chronic inflammatory disease,” said Priyavrat Vashisth, a doctoral candidate in chemistry and co-author of the study. “People often confuse it with cancer, but it’s not like cancer. It’s a tissue that is growing and keeps growing during each menstrual cycle.”
Despite its prevalence, the causes of the chronic disease remain difficult to decipher, Tanner said.
“We have a couple of leading theories as to what causes it, but we don’t definitively know,” she said. “Right now, the only way you can really diagnose endometriosis is through laparoscopy.”
A laparoscopy is a minimally invasive procedure in which a doctor makes incisions in the abdomen and inserts a laparoscope – a thin rod with a video camera affixed to it – to look for problems in the stomach and pelvic region.
If a doctor is able to diagnose endometriosis, treatment options, too, are limited. One involves hormone therapy to reduce growth of endometrial tissue, and the second is surgery to remove the tissues growing outside of the uterus.
“The hormone therapy is likely to reduce growth, but it presents a problem if you would like to conceive,” Tanner said. “And if you have the surgery, it can be very effective. But endometriosis has a very high recurrence rate.
“So, you have the surgery and, in a few years, you need it again. It’s really more management than treatment.”
Instead, Tanner and Vashisth are working on a way to use the body’s own defense systems to diagnose and treat endometriosis.
Neutrophils are a type of white blood cell that respond to inflammation. By creating a nanoparticle that can “hitchhike” on neutrophils, the researchers can ride the bloodstream to the endometrial tissue outside of the uterus.
“Whenever you get an infection or sustain an injury, your body recruits white blood cells as part of its first line of defense,” Vashisth said. “Neutrophils are the most abundant white blood cells and are among the first immune cells recruited to sites of inflammation. They are also highly over-expressed at endometrial lesion sites.
“What we’re doing is using that to our advantage.”
Each of the nanoparticles has a microscopic amount of gold inside. This tiny amount of metal shows clearly on an X-ray.
“Gold is very high contrast, so if you take an X-ray or a CT scan, it shows up on that image,” Tanner said. “If you look at that image and see huge areas of inflammation, you’d be able to say, ‘Yes, this person has endometriosis.’
“This means that we might be able to diagnose endometriosis through just an injection and an X-ray without having to do surgery.”
Gold also reacts to near-infrared light by heating, offering a potential path to treatment, the researchers said.
“Once the nanoparticles with the gold cores have been delivered to the sites, we can use a near-infrared laser, which is used in many clinical therapies, to target that gold,” Vashisth said. “This can potentially lead to the selective killing of only the cells that we’re trying to target.”
By heating only the gold-bearing nanoparticles, the researchers can kill endometrial tissues. The body’s natural processes can then excrete both the nanoparticles and the dead endometrial cells.
The team tested nanoparticles in laboratory-grown cells and human blood samples, but the research is still in its earliest stages, Tanner said. Future work would need to test nanoparticles in animal models before it could be considered for real-world applications.
Although there’s a long way to go, the goal is to develop a less invasive and more affordable method to treat and diagnose the disease, the researchers said.
“If we’re able to get this to the next stage, it’s going to be affordable because everything except the gold is very inexpensive,” Vashisth said. “And the gold we’re using in such small quantities that it is also not terribly expensive.
“We want to develop a therapy that gives a long-term solution to this problem that people can actually afford. Many people cannot afford to get treated for endometriosis right now, and they’re just living through the pain.”
This material was supported in part by the National Science Foundation grant no. 2236629.
By Clara Turnage
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