A new study is the first to utilize a human cell-based wound closure model, resulting in novel insights into healing physiology without inflicting painful wounds on animals.

Researchers at Boston University’s Department of Biomedical Engineering teamed up with Harvard’s Wyss Institute to create an entirely human model of wound healing by mixing two types of human cells known to be involved with healing – fibroblasts and endothelia cells – into a gel composed of fibrin and collagen. Within three days, blood vessels began to grow in the model, creating vascularized tissue.

After slicing through this vascularized tissue, the researchers then spent several days observing how the fabricated wounds healed in real time. They were able to conclude that, of the two cell types used, fibroblasts are the key drivers for wound closure.

While animals are typically used to study wound healing and treatments, scientists admit that there are key differences between the way wounds heal in animals when compared to humans. For example, in mice and rats, the skin contracts to close the wound, whereas in humans, granulation tissue forms to close the wound. Granulation is not needed for wound healing in animals.

Despite these essential differences, thousands of painful and expensive procedures are carried out to study wounds using animals, typically on mice, rats, dogs, pigs and sheep.

The National Institute of Arthritis and Musculoskeletal and Skin Diseases, along with the National Institute of General Medical Sciences are the main funders of wounding experiments on animals. These experiments usually involve excising or punching a hole in the skin. In mice this is sometimes done in the ear. Complications include pain, infection, malnutrition and death.

The company TRIM-edicine, Inc., in conjunction with Ohio State University, is using dogs and mice to study their topical treatment for chronic wounds and has received close to $1 million in NIH funding. Allander Biotecnologlies, LLC, is using dogs and mice to study the treatment of excruciating radiation-induced burns, receiving $1.2 million from NIH in 2020 alone.

These outdated and painful animal experiments stand in stark contrast to the modern, human-relevant, and humane approach developed by the teams at BU and Harvard. Their wound closure model successfully demonstrates how new methods in tissue engineering and biomechanical modeling enable scientists to study the microphysiology of wound healing without harming and killing animals.

CAARE will continue to push for the replacement of animals by promoting The Humane Research and Testing Act, legislation that, if passed will create a dedicated NIH center for non-animal research to fund and train scientists to use these new methods.

Citizens for Alternatives to Animal Research (CAARE), is a 501(c)(3) non-profit organization, established to highlight and promote research without animals.

Please donate to support CAARE’s mission to reduce animal suffering by disseminating information about the power and progress of research without animals.