Bioengineering breakthrough has corneal blindness in its sights

written by Nancy Ceresia

As the transparent and protective outer layer of our eyes, the cornea is in a very real sense the window through which we see the world; damaging it can lead to corneal blindness, prompting the need for a corneal transplant, one of the most commonly performed. The tragedy is that this relatively easy replacement is denied to millions of people with corneal blindness—there just aren’t enough donated corneas to go around.

The demand for donated human corneas in fact far exceeds the supply. To make matters worse, recipients' bodies can reject donor corneas; success depends on both the availability of good-quality donor tissue and the patient’s condition. Some afflictions such as inactive central scars or keratoconus (the gradual thinning and bulging of the cornea) lend themselves well to transplants, but others like chemical burns or nerve scarring left by herpes zoster ophthalmicus (caused by the chicken pox virus) do not.

Although prosthetic artificial corneas (or keratoprostheses) are available as a substitute for donor corneas and, in some studies, appear to have more success in patients with added eye ailments, their post-surgical complications and high cost make them a last resort. Bottom line: no keratoprosthesis has yet met the gold standard for a successful corneal implant.

All of these factors combine to leave many sufferers of corneal blindness with no treatment options.

Thankfully, researchers like Dr. Mehrdad Rafat, a University of Ottawa alumnus and Ottawa Health Research Institute (OHRI) Fellow, were motivated to address these problems. Dr. Rafat and a multidisciplinary team pioneered by Dr. May Griffith at the University of Ottawa have created a bioengineered material called hybrid interpenetrating polymer network (HIPN) that mimics the human cornea; as its names implies, it's a blend of natural macromolecules in the body and of synthetic polymeric components.

Not only would the HIPN improve the body’s acceptance of an artificial cornea by actually encouraging the regeneration of a patient’s own surrounding tissue, it could also be manufactured for much less than current artificial corneas (under $1000 vs. $3000+). It could also overcome supply challenges by eliminating the dependence on human donation as the predominant source of replacement corneas.

During his doctoral studies, Dr. Rafat belonged to a multidisciplinary team of engineers, cell biologists, chemists, and eye surgeons. “A variety of disciplinary skills is definitely required to tackle complicated problems in medicine and engineer a solution,” says Rafat. “I think that studying at the University of Ottawa provided me with a great opportunity to meet and work with some of the best scientists and educators in Canada and in the world.”

Although the hybrid bioengineered cornea has been deemed a success, the road to marketing the technology is fraught with new challenges. Dr. Rafat is working on its transfer and commercialization in close partnership with Dr. Griffith’s team at OHRI, and with EyegenixTM (a division of Cellular Bioengineering Inc,) the private company acquiring the technology. The process involves designing procedures for complying with Good Manufacturing Practices (GMP) to ensure the quality and safety of the material, and for adhering to the policies of regulatory agencies—a prerequisite to clinical trials in humans and, ultimately, to adoption by practicing physicians.

Still, Rafat explains that convincing practicing physicians of the validity of HIPN as a treatment option is a huge task on its own. “The medical community is highly conservative, and more likely to stick with the tried and true than to experiment a new product on their own patients,” explains Rafat. “A product in R&D may be successful and gather a lot of publicity, but unless physicians and surgeons are actually going to use it, it will fail.”

Despite these obstacles, Mehrdad Rafat remains sure it’s only a matter of time before people will be treated with this technology. “I’m confident that we will make a reliable and economical solution (...) ensuring no one in the world has to experience corneal blindness for lack of available corneas.”