Nav: Home

Stanford researchers discover gel reduces scar tissue after surgery in animals

August 07, 2019

Researchers at Stanford University have found that spraying a gel on the internal tissues of animals after cardiac surgery greatly reduces adhesions, fibrous bands that form between internal organs and tissues. Adhesions can cause serious, even fatal, complications.

The gel, developed at Stanford to deliver medications, was far more effective than adhesion prevention materials currently on the market, the researchers said. It appeared to be safe in the animal study.

"The difference between what we saw after using the gel and what we normally see after surgery was drastic," said Joseph Woo, MD, professor and chair of cardiothoracic surgery and the Norman E. Shumway Professor.

A paper describing the research published August 7 in Nature Biomedical Engineering. Woo and Eric Appel, PhD, an assistant professor of materials science and engineering, are the senior authors. Lyndsay Stapleton, a graduate student in bioengineering, is the lead author.

Adhesions form after 95% of surgeries. Some are harmless, but after abdominal surgeries, they can twist or compress the intestines, causing life-threatening blockages. Gynecological surgery can also lead to adhesions that cause infertility. In cardiac re-operations, common for those born with heart defects, adhesions increase the risk of complications.

Previous methods, lot of failures

Methods to prevent adhesions -- including animal membranes, sheets of rubber and mineral oil -- have existed for more 100 years, but they have mostly failed. Current adhesion barriers approved by the Food and Drug Administration are rarely used; they are difficult to deploy and are considered ineffective.

The Stanford researchers had long pondered a solution to the adhesion problem. But one day, when Stapleton was working with lab rats to develop an injectable therapy to reduce tissue damage following a heart attack, Appel suggested she try spraying a polymer-nanoparticle hydrogel onto the hearts and surrounding tissue after surgery to see if it reduced the formation of adhesions. Weeks later, when she operated on the animals again, she saw that no adhesions had formed.

"It was pretty striking," she said. "I thought, 'Oh wow, we could be onto something here.'"

The researchers decided to conduct a study. First, they formulated four additional gels with a range of properties. Then, after inducing heart attacks in rats, they randomly divided the animals into eight treatment groups: five that each received a different gel, two that received commercially available adhesion barriers and one that received no treatment.

Four weeks later, the rats that had received no treatment or either of the two commercial adhesion barriers had formed dense adhesions: Their hearts were connected to their chest walls. The rats that were treated with two of the five gels had formed moderate to dense adhesions. The rats treated with the other three gels fared much better, with very few adhesions. PNP 1:10, the gel Stapleton initially tried, completely prevented adhesions.

The researchers then tested PNP 1:10 in sheep, whose hearts are similar in size and shape to human hearts; they found similar results.

Like mayonnaise

PNP 1:10 was stiff enough to stick, but not so stiff it detached from the organs, Appel said. "It was sort of a Goldilocks sweet spot." He compared PNP 1:10 to mayonnaise: thick, but easily spreadable. That property allows it to be sprayed onto an organ but then immediately reform its original strength.

The gel also has the ideal tension between stickiness and slipperiness: "It covers all of the irregular surfaces of the heart, adhering to the tissues, but not to itself," Woo said.

And it's flexible, allowing the heart to beat: "The gel doesn't prevent tissues from moving around," Appel said. "It simply provides a physical barrier to keep them from sticking to each other."

PNP 1:10 dissolves and is absorbed by the body about two weeks after its application -- enough time for healing to occur, Appel said. PNP 1:10 is not approved for use in patients, but it is made of components that the Food and Drug Administration has approved. As part of the study, the researchers tested the rats to see if they showed any reaction to the gel; they saw no abnormalities in the surrounding tissues or in the blood.

The researchers next plan to try PNP 1:10 in abdominal surgery in rats. They hope to conduct human trials soon.
-end-
Woo and Appel are members of Stanford Bio-X. Woo is associate director of the Stanford Cardiovascular Institute, and Appel is a faculty fellow at the ChEM-H Institute.

Other Stanford study co-authors are graduate students Amanda Steele, Anthony Yu and Gillie Agmon; cardiothoracic surgery residents Hanjay Wang, MD, and Michael Paulsen, MD; postdoctoral scholars Hector Lopez Hernandez, PhD, and Yuko Tada, PhD; visiting scholar Anton Smith, PhD; research assistants Akshara Thakore, Haley Lucian, Anahita Eskandari, Justin Farry and Kevin Jaatinen; undergraduate student Kailey Totherow; clinical veterinarian Sam Baker, DVM; former research assistant Camille Hironaka; medical student Kiah Williams; perfusionists Hunter Bergamasco, Clifton Marschel and Blaine Chadwick; and Michael Ma, MD, assistant professor of cardiothoracic surgery.

The work was funded by Stanford Bio-X Interdisciplinary Initiatives Seed Grants Program, the Stanford-Coulter Translational Research Grants Program, the National Institutes of Health (grant R01HL089315-01), the American Heart Association, the National Science Foundation-funded California Alliance, a Stanford Interdisciplinary Graduate Fellowship and the American Association for Thoracic Surgery Summer.

Stanford's departments of Cardiothoracic Surgery and of Materials Science and Engineering also supported the work.

The Stanford University School of Medicine consistently ranks among the nation's top medical schools, integrating research, medical education, patient care and community service. For more news about the school, please visit http://med.stanford.edu/school.html. The medical school is part of Stanford Medicine, which includes Stanford Health Care and Stanford Children's Health. For information about all three, please visit http://med.stanford.edu.

Stanford Medicine

Related Science Articles:

75 science societies urge the education department to base Title IX sexual harassment regulations on evidence and science
The American Educational Research Association (AERA) and the American Association for the Advancement of Science (AAAS) today led 75 scientific societies in submitting comments on the US Department of Education's proposed changes to Title IX regulations.
Science/Science Careers' survey ranks top biotech, biopharma, and pharma employers
The Science and Science Careers' 2018 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Science in the palm of your hand: How citizen science transforms passive learners
Citizen science projects can engage even children who previously were not interested in science.
Applied science may yield more translational research publications than basic science
While translational research can happen at any stage of the research process, a recent investigation of behavioral and social science research awards granted by the NIH between 2008 and 2014 revealed that applied science yielded a higher volume of translational research publications than basic science, according to a study published May 9, 2018 in the open-access journal PLOS ONE by Xueying Han from the Science and Technology Policy Institute, USA, and colleagues.
Prominent academics, including Salk's Thomas Albright, call for more science in forensic science
Six scientists who recently served on the National Commission on Forensic Science are calling on the scientific community at large to advocate for increased research and financial support of forensic science as well as the introduction of empirical testing requirements to ensure the validity of outcomes.
World Science Forum 2017 Jordan issues Science for Peace Declaration
On behalf of the coordinating organizations responsible for delivering the World Science Forum Jordan, the concluding Science for Peace Declaration issued at the Dead Sea represents a global call for action to science and society to build a future that promises greater equality, security and opportunity for all, and in which science plays an increasingly prominent role as an enabler of fair and sustainable development.
PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.
Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.
Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.
More Science News and Science Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Dispatch 3: Shared Immunity
More than a million people have caught Covid-19, and tens of thousands have died. But thousands more have survived and recovered. A week or so ago (aka, what feels like ten years in corona time) producer Molly Webster learned that many of those survivors possess a kind of superpower: antibodies trained to fight the virus. Not only that, they might be able to pass this power on to the people who are sick with corona, and still in the fight. Today we have the story of an experimental treatment that's popping up all over the country: convalescent plasma transfusion, a century-old procedure that some say may become one of our best weapons against this devastating, new disease.   If you have recovered from Covid-19 and want to donate plasma, national and local donation registries are gearing up to collect blood.  To sign up with the American Red Cross, a national organization that works in local communities, head here.  To find out more about the The National COVID-19 Convalescent Plasma Project, which we spoke about in our episode, including information on clinical trials or plasma donation projects in your community, go here.  And if you are in the greater New York City area, and want to donate convalescent plasma, head over to the New York Blood Center to sign up. Or, register with specific NYC hospitals here.   If you are sick with Covid-19, and are interested in participating in a clinical trial, or are looking for a plasma donor match, check in with your local hospital, university, or blood center for more; you can also find more information on trials at The National COVID-19 Convalescent Plasma Project. And lastly, Tatiana Prowell's tweet that tipped us off is here. This episode was reported by Molly Webster and produced by Pat Walters. Special thanks to Drs. Evan Bloch and Tim Byun, as well as the Albert Einstein College of Medicine.  Support Radiolab today at Radiolab.org/donate.