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At UC Merced, Research On Silk Implants Could Fight HIV

Jun 21, 2017

UC Merced isn’t the first place people think of when it comes to finding new ways to prevent the spread of HIV globally. But thanks to one professor the university is now working with scientists around the globe to find an alternative way to prevent the virus from infecting people.

"Some people just don't want to, can't, have troubles taking a pill every day." - Dr. Simon Paul, UCSF Fresno
Dr. Simon Paul sees about 1,000 patients at UCSF Fresno. He says if these strips work it would provide another option for his patients.
Credit Ezra David Romero / Valley Public Radio

People try to prevent themselves from getting HIV by doing multiple things. They either don’t have sex, use condoms or take a daily pill called PrEP or TRUVADA. Dr. Simon Paul with UCSF Fresno specializes in infectious diseases and HIV. He sees about 1,000 patients and says many people struggle to follow these recommendations, especially taking a daily pill.

“Some people just don’t want to, can’t, have troubles taking a pill every day,” Paul says. “There’s always been trouble with people practicing safe sex and doing everything you’re supposed to do to prevent HIV. So a pill every day may work for some people but not for others.”

This is an even bigger problem in other parts of the world. It can be too hot for medicines to survive in third world countries and they’re often too expensive. A UC Merced professor thinks she may have found a way to inexpensively prevent the spread of HIV without having to take a daily pill.

“I realized, wow, I could train my research in that direction then I could have potential real impact on a disease that really affects the world,” says LiWang.  

"The question is what will this do in a person. So the next step is to try it in an animal." - Patty LiWang, UC Merced

Biochemist Patty LiWang studies proteins secreted by cells that on their own prevent HIV from   binding itself to cells. 

Biochemist Patty LiWang her project is funded through the end of the year. She hopes to be awarded additional funds to complete her research.
Credit Ezra David Romero / Valley Public Radio

“When our lab work went well the National Institutes of Health, which does most of the funding made it clear that they were not interested in just lab work that goes well,” says LiWang. “They want actual how are you going to get this into people.”

Now it’s her goal to find a way to get these proteins into the body.  

We’re at her lab at the Old Castle Air Force Base north of Merced where her team is purifying proteins. This is done by isolating one or a few proteins from cells or tissue. These proteins aren’t harmed by HIV. The problem is that the proteins don’t work if they are ingested.

That’s where silk comes in. A professor at Tuft’s University found a protein in silk that stabilizes medicine that can withstand extreme conditions without deterioration. The idea is to insert strips of the silk soaked in the proteins into the reproductive and digestive tracts.

She’s testing two types of strips. A quick dissolve option and a second that could slowly and steadily release the inhibitors over a period of a month. This differs from the daily pill in that PrEP is taken orally and dissolves in the blood stream. These strips are inserted and would coat the area of the body where HIV enters.

"If you stop HIV from getting in there for any reasonable amount of time you should be fine,” LiWang says. “So it dies if it doesn’t infect a cell and your body is very good at clearing out foreign viruses.”

The silk in the strips comes from silkworm cocoons.
Credit Ezra David Romero / Valley Public Radio

One of LiWang’s collaborators is Carolina Herrera at Imperial College London in the UK. She’s testing the how the strips react to body tissue when exposed to HIV.

“So we haven’t seen any marker of inflammation and anything that has been slightly changed is not sufficiently worrying that the product would be dangerous,” says Herrera. “So up to now [it’s] very promising.”

Herrera’s studied HIV prevention for 12 years and says this way of preventing HIV could be popular because the strips can withstand temperatures of up to 122 degrees.

Also, while presenting the data the team realized the product already holds a positive connotation unlike pills do.

“People started commenting about how interesting it was and how they could imagine a commercial to sell the product,” Herrera says. “That’s when realized silk had that connotation of something glamorous or something silky.”

She sees this interest as an indicator that people would actually use the strips. The next step is to test the film in animals. Satya Dandekar in the School of Medicine at UC Davis is testing the inserts in macaques because their bodily systems are the most like humans.

“Our goal is to examine whether the silk is stable,” Dandekar says. “It should not cause any inflammation or irritation.”

Dandekar is trying to figure out what size strip is easiest to place in the body and to see how it reacts. Dr. Carl Dieffenbach is the director of NIH’s Division of AIDS. He says the strips could give people another option for preventing the virus when exposed.

The proteins are refined in a long metal tube.
Credit Ezra David Romero / Valley Public Radio

“It’s a logical thing to consider using based on the fact silk is one of the key ingredients in sutures,” Dieffenbach says. “When you would want something to dissolve it make sense. If this was proven to be safe and effective it offers an alternative.”  

He says if everything proves successful the inserts could be on the market in about a decade.

Back in Patricia LiWang’s lab she and her students are continually working to strengthen the HIV inhibitors they’re creating. The thing is there’s only about six months left of funding.

“We’ve shown we can have sustained release in active amounts,” LiWang says. “The question is what will this do in a person so the next step is to try it in an animal.”

As LiWang’s team finishes up their research she’s putting together a proposal for further testing in monkeys and then humans. If that gets funded and works in people then this new way of preventing the spread of HIV would have its origin here in the Valley at UC Merced.