Gut Check: The Evolution of Polymer Science


By Steve Harrison, M.A, Ph.D.

Senior Vice President and Chief Scientific Officer

What if some of the most common medical conditions afflicting society today could be managed through the digestive system? We are increasingly finding evidence linking common ailments to the gut, and scientists, including our team here at Relypsa, are focused on investigating this concept in the hopes that we can create new treatments to address common diseases at this single source.

I’ll explain. Some people have difficulty managing the levels of certain minerals in their blood, such as potassium. Others are sensitive to the presence of naturally-occurring components of their food. By removing such substances from the gut, otherwise known as the gastrointestinal (GI) tract, we may be able to treat numerous health conditions and problems in ways that haven’t been possible before. For example, lowering potassium levels in the gut can help to reduce elevated potassium levels in the blood, helping to reduce the risk of the condition hyperkalemia. Also, removing allergenic components in food could stop them from irritating the gut lining. The technology that can be used to target these disease-causing chemicals in the GI tract is a class of substances that have already been in use for decades – polymers.

Polymers are large molecules made up of repeating structural units that I believe may be the key to a paradigm shift in how we approach certain diseases. Polymers not only exist in nature – proteins, starch, cellulose and DNA – but they also can be manufactured in a laboratory for a variety of purposes.

“…we have championed a different approach. Instead of only serving as a vehicle to deliver or protect a medicine, the polymer can become the medicine itself, which I find very exciting.”

Natural polymers have been modified and processed over many centuries for various applications, while synthetic polymers are among the most widely used and important type of materials today, including plastics and coatings.

Polymers also have a long history in medicine, starting in the 1940s, when they were used in cornea replacement surgery; through the 1950s and 1960s, when they were used to improve artificial heart and dialysis machines; into the 1970s and 1980s, when eyeglass lenses and contact lenses were made of polymers.

Throughout my career, I’ve seen this science transform medicine. Today, many biomaterials are made of or contain some polymer, including heart valve replacements; sutures and staples to close wounds; pins, rods and screws for orthopedic fixation devices; cardiovascular stents; and even artificial skin.

For people suffering from certain diseases, polymers are often used as a medicine delivery system. In this method, the polymer is bound to a medicine for potential use in diseases such as multiple sclerosis and Crohn’s disease. The use of polymers may help to protect the treatment from being attacked and destroyed by the immune system or shield the drug from other biological mechanisms that may disable or degrade the drug.

At Relypsa, we have championed a different approach. Instead of only serving as a vehicle to deliver or protect a medicine, the polymer can become the medicine itself, which I find very exciting. In fact, I joined Relypsa last year to become a part of the team that would take polymer science to new grounds.

This new polymer technology can recognize, adhere to and remove a molecule that is causing disease. Importantly our polymer medicines, unlike other chemicals that are absorbed from the gut into the body and the blood stream, aren’t absorbed at all. Instead, they are designed to act and remain in the GI tract.

Relypsa has the ability to alter the binding properties of polymers to make them selective for different molecules, and so different polymer medicines can be designed to treat a variety of conditions that have therapeutic targets residing in the gut. There are many possible areas of exploration including ion imbalance, diabetes and gut inflammation. Another particularly exciting new area of application could be the treatment of diseases caused by gut bacteria.

I believe the future for polymer science will be just as exciting as its past, as we search for new ways to address conditions that can be treated in the gut. 

Steve joined Relypsa in December 2014 with 20 years’ tenure in biotechnology and pharmaceutical discovery and development. A biochemist and molecular biologist, he holds a Ph.D. in molecular biology, and an M.A. and B.A. in biochemistry – all from the University of Cambridge in the United Kingdom.