English / Japanese

[Department of Nursing & Health, School of Nursing & Health]
Professor YONEDA Masahiko

Tackling treatment and solutions for pressure ulcers in nursing care from a foundation of thirty-plus years of hyaluronic acid research.

Hyaluronic Acid With Healing Wounds

If you mention hyaluronic acid, there are probably many people who think it is an ingredient that has something to do with beauty since it is being used in cosmetics and supplements recently.

Hyaluronic acid is a type of extracellular matrix, which surrounds cells and determines their shape, and is a polysaccharide that bonds with proteins. Contained in skin, synovial fluid, the vitreous body of the eyeball, and other places, it generally is known for its lubricating effects and buffering actions.

In humans, the body is built through cell differentiation from the ovum and cell migration. The functions of cells, like the ones in skin, bones, and teeth, are determined when they take shape. Normally, their shapes are fixed, but when a person suffers a wound, cells move to that spot, are broken down once, and then build new cells. This is how wounds heal. For example, you might think of it in the same way as when a building partially collapses: you tear down the building, turn it into a vacant lot, and rebuild it. Hyaluronic acid is what does the work of preparing the surrounding environment at this time. Hyaluronic acid has high viscosity and water-holding capacity, so it plays a role in helping to loosen cells and make them easier to move.

Applications of Hyaluronic Acid in Medical Settings

Hyaluronic acid exists in parts of the body that move and in all joints, so it also carries the role of shock absorber (buffer device). If there were no hyaluronic acid, the shock just from walking would be carried to the brain and no doubt cause a brain concussion.

Arthritis is a disease in which water and blood accumulate in the joints, making it painful to walk, but if you remove the accumulated water content and replace it by injecting hyaluronic acid, the pain goes away. It is also thought to have analgesic effects, although this has not been proven yet.

In the realm of ophthalmology, surgeries are being performed for such conditions as cataracts and glaucoma by varying the levels of hyaluronic acid that have accumulated inside the eyeball. When cataract patients wear artificial lenses, hyaluronic acid is inserted under the lenses to prevent them from falling off even if the patient looks up. It naturally metabolizes and disappears in about two days after that, so there is no sense of discomfort.

In addition, when ova are released from the ovaries, they are covered in a thick membrane of hyaluronic acid, without which a woman would become infertile. Hyaluronic acid controls cell division, cell proliferation, and cell differentiation in organisms, and is thought to have a definite connection to diseases and ailments in which cells change shape, such as metastatic cancer.

A Community Medical Care Project for Curing Pressure Ulcers

Making the most of my basic research until now, I currently am conducting joint research on “Pressure Ulcers—Bed Sores” with a team from the National Center for Geriatrics and Gerontology in ōbu City, Aichi Prefecture.

Pressure ulcers, which are often seen in elderly bedridden patients and patients receiving long-term medical treatment, are a kind of gangrene that occurs because of pressure from bedding and so forth. There is no worry of this in hospitals, because they change the positions of patients every two or three hours, but that is difficult to do in the case home care, and it is not uncommon to see patients who suffer from it once and do not take care of it properly, causing it to get worse.

So, forming a team of dermatologists, biochemists, pharmacists, nurses, and NPOs, we set about on a project to grasp the actual conditions in local areas and to treat pressure ulcers from the angle of nursing care. By making links between the specialized knowledge of researchers and the wide range of information held by nurses and NPOs, which deal more closely with patients, we are hoping that we can get better results. In addition to our university, we are joining forces with other universities in Aichi Prefecture and Gifu Prefecture, so it is turning into a fairly wide-reaching project. Its reputation has spread so widely that patients have started to come from far away.

Results of Molecular Studies and My Feelings as a Researcher

Normal wounds heal in three to four days, but when wounds become chronic, infections occur. Pressure ulcers are more troublesome because, within a single wound, the parts that are beginning to recover, the parts that are getting worse, and the parts that are in stasis are all tangled up together. It used to be difficult to distinguish between those parts, but we have been able to collect a sizable body of research results over the past few years. As I explained earlier, in wounds and inflammations, the cell structures of those parts are completely broken down once and then new cell structures are built, but we learned that it is possible to judge which parts are recovering and which parts are getting worse by using antibodies to examine fragments of the broken cell structures. For example, analyzing the exudate compounds, we were able to learn that in cases when no protein or collagen is present and in cases when low-molecular hyaluronic acid is present, there is a tendency toward recovery.

I have continued my basic research on hyaluronic acid for more than thirty years, from a time when its existence was still not widely known. In terms of my ethics as a researcher, I would like to “take care of it until the end,” that is, to follow through with this research until the end of my life. In my younger days, I had some tough times with research, but I am enjoying it the most right now. I am just starting to feel as though I can see the whole picture, and I am studying much more now than I ever did in the past. If that leads to something that is useful for society, then I will be very pleased.

Toward Developing New Human Resources and Local Ties

The School of Nursing and Health at the Aichi Prefectural University has fairly substantial laboratory facilities for a university with a nursing science program. As for the future, I really hope we can train nurses who are proficient in the areas of biochemistry and microbiology. I am also looking to develop new human resources who can make links between nursing sites and research, as the medical research team on pressure ulcers has done.

Hyaluronic acid, the topic of my life’s research, is now attracting attention in the field of regenerative medicine and is being used in surgical procedures to fill wounds by mixing it with collagen and making it a base for cell structures. Also, work has begun overseas to use it as a means of medicine delivery by mixing hard-to-dissolve medicines with hyaluronic acid to make them easier to dissolve. There are still aspects of hyaluronic acid that we do not understand, and only its physical properties have been receiving attention, but by focusing more on its functionality, I believe its range of applications will spread even further.

If any of you are interested in this kind of research, please give a knock on my office door. By actually talking and brainstorming with each other, and in some cases doing experiments together, you might be able to help me find some course of action. If those of you from the local community or companies could help me find an unexpected use value or clue for my research, I would be much obliged. Besides, I believe that is also an important role of universities.


Department of Nursing & Health, School of Nursing & Health

Professor YONEDA Masahiko

Areas of Specialty: Biochemistry, Molecular Biology

As a young boy, he had a shy personality, so he was good at looking things up by himself rather than asking other people. During elementary school, he read such things as university science textbooks and Japanese-language editions of American science magazines, making up his mind “to become a scholar.” Fascinated by “the beauty of the forms of biological life,” he aspired to approach living things chemically. He has been involved in hyaluronic acid research since his days in the Graduate School of Science at Nagoya University. After working at the Institute for Molecular Science of Medicine at Aichi Medical University and elsewhere, he took a position as Professor in the School of Nursing and Health at our university in fiscal year 2004. He is a Doctor of Science.

Interview: YAMAGUCHI Aya; Writer: MIYAMOTO Yumiko


Go to Top