Kristi Anseth: The engineer who teaches our body to repair itself: “We have regenerated skin, cartilage and blood vessels, but we still have to do more” | Health & Wellness

The ancient Egyptians used sutures made from flaxen ribbons and animal tendons, and in South Africa and India the heads of large biting ants were used to hold the edges of wounds together. Human beings have used natural and artificial materials for centuries to repair all kinds of tissues. More than 4,000 years later, the American engineer Kristi Anseth investigates how the most modern and sophisticated biomaterials help regenerate cartilage, heal bones faster and better understand some diseases.

“Biomaterials can play a key role in helping our bodies heal themselves,” says Anseth, who received the international L’Oréal-UNESCO For Women in Science 2020 award a few days ago (for women in science, in Spanish) in Paris, where this interview took place. This 54-year-old researcher, specialized in regenerative medicine and tissue engineering, designs synthetic materials that mimic our tissues: “We are not only using materials designed for textile products such as mattresses or clothing, but we are making them able to interact with the body” .

In the face of injury or illness, biomaterials “can be used to deliver molecules that help tissues heal faster.” “When you inject cells alone, sometimes they don’t survive very well and they need some kind of three-dimensional environment, a biomaterial that can provide them with the scaffolding and instructions on where and when to grow the right kind of tissue,” explains Anseth, who is also a professor of Surgery at the University of Colorado.

There are many types of biomaterials: from heart valves to hip joint replacements to dental implants. There are made with cells, living tissues, metals, ceramics, plastic or glass. The US National Institute for Biomedical Imaging and Bioengineering indicates that they can be designed into molded or machined parts, coatings, fibers, films, foams, and fabrics for biomedical products and devices. Among the biomaterials currently used, Anseth highlights the potential of degradable sutures, which can “join tissues and dissolve once they have healed.”

It also highlights those designed to cure arthritis, an inflammation of the joints that can cause pain and swelling. What usually happens, according to Anseth, is that the cartilage lining a joint — say, the knee — wears down. “When you don’t have that lubricating surface and one bone interacts with another, it’s painful,” she says. But “we have a lot of extra cartilage in our body”, so it is possible to “take it from somewhere else, grow the cells in a bioreactor and take them to the joint to grow and regenerate that cartilage surface”.

In addition, there are some proteins, called growth factors, that can also “help tissues and cells grow and repair themselves.” Something that, according to account, can be useful in case of fracture. “Even though our bones usually heal, sometimes you have to put on a cast or even resort to plates and screws. It’s a long process,” he explains. Also, “some large defects caused by a car accident or bone cancer may not heal very well.”

The engineer explains that there is a growth factor in the bone marrow that can be useful in these cases. But there’s a catch: “It can’t be given on its own to a really big bone injury because it could degrade.” This is where biomaterials come into play, which can be used “to deliver that factor locally for longer periods of time and at the right dose, time and place.”

Risk of infections

Despite their great potential, biomaterials also have their limitations. If they are not biocompatible, there is a risk that they will cause infections. The presence of exogenous materials in the human body dates back to prehistory, as indicated by research published in the scientific journal processes. A spearhead embedded in the hip of Kennewick Man, a 9,000-year-old skeleton found in Washington state, and the use of charcoal particles for tattooing are examples of foreign bodies tolerated centuries ago by the host.

There are two key factors that determine the biocompatibility of a material, according to a review published in materials: the reaction of the host and its degradation in the body. Sometimes, according to Anseth, “it is difficult to get biomaterials to degrade at the same rate as tissue is formed.” In addition, that a biomaterial has all the desired properties “is complicated”. “Bones, for example, are really strong and most biomaterials are either not that strong or they don’t have the same properties”, adds the researcher.

More research is still needed to unravel all the mysteries of the human body. “We have regenerated skin, cartilage and blood vessels, and we have also helped bones heal faster. But we still have to do more”, says the engineer, who poses the following question: “Why, when you have a heart attack, does the heart not regenerate in the same way that the skeletal muscles that we use to walk and exercise do?” .

In the next decade, Anseth predicts “a significant advance in medicine.” “We are going to see how we can intervene earlier to make the muscles grow, repair cartilage or heal nerves.” “Things that might not even be possible right now,” she adds. One of the most ambitious goals of engineering is to prevent health problems related to aging. Age, which is a risk factor for multiple chronic diseases, is often accompanied by a loss of body mass.

As you age, “something happens to our cells”: “They have divided many times and are no longer as active or able to repair themselves as much,” he says. The biomaterials, she says, could provide young stem cells to help re-grow muscles. “Aging is a complex natural process that we can’t necessarily reverse, but we can improve quality of life as we experience some degeneration in our joints, muscles and hearts.”

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