‘Bone glue’ could reduce the need for bone transplants

Dr. Dror Seliktar and from left, graduate students Maya Gonen, Maya Livnat, and Liora Almany-Levi proudly hold bottles of Gelrin.Researchers at two different Israeli universities have recently developed novel materials that respectively stimulate speedy bone and cartilage repair, and enable …

Dr. Dror Seliktar and from left, graduate students Maya Gonen, Maya Livnat, and Liora Almany-Levi proudly hold bottles of Gelrin.Researchers at two different Israeli universities have recently developed novel materials that respectively stimulate speedy bone and cartilage repair, and enable faster and improved healing of injuries.

At the Technion in Haifa, Dr. Dror Seliktar has invented a unique gel called Gelrin that he believes will reduce the need for bone transplants and heal bone defects caused by cancer or trauma. There is large potential market for the product, according to Seliktar, as orthopedic bone procedures will soon reach one million annually in the U.S. alone.

Gelrin’s “bone glue” combines biological and synthetic components that when mixed together, supports broken bones and allows them to grow new bone tissue. After the broken bone has fused, the material is broken down in the body, says Seliktar, who was aided in his research by master’s student Liora Almany-Levi.

Seliktar says Gelrin could also be used for sports injuries and fused vertebral disks, as well as reduce the need for hip replacements in the elderly by preventing degeneration of cartilage and stimulating regrowth in the joints.

Gelrin is comprised of Fibrin and the polyethylene, Glycol. Fibrinogen is the natural substance that causes blood to clot, while the synthetic PEG is already used as a non-adhesive barrier in surgery and for making contact lenses.

The Technion researchers have found a way to bind the molecules of the two substances to form a new material that has biological characteristics and can also be adjusted to different strengths.

“It’s a brand-new material engineered molecule by molecule, not just mixed together,” Seliktar said.

The cells of the body identify the new material as “a friendly substance,” on which regenerated tissue that supplements boneless areas can be grown. “In fact, the bone tissue grows within the Gelrin; and as soon as the tissue fills the space, the material breaks down and washes out in the urine,” Seliktar explains, adding that one of its advantages is that it can be injected into the damaged area without need for surgery.

Instead of injecting collagen into fractures and worn-down cartilage in joints, the gel will create a good biological template for tissue regeneration that also supports a physical load, he explained.

Orthopedics will still need metallic pins and plates to affix the parts, but bone and cartilage growth will actually be facilitated because the body is “tricked” into thinking that the substance is solely a biological substance.

The gel doesn’t leach out like collagen – which can take a year to heal – but remains until new tissue takes its place much faster, he said.

Until now, tests with Gelrin have been conducted on cells grown under laboratory conditions, with trials on rats to be completed in about six months. Seliktar says that those trials will lead to trials on larger animals such as pigs and sheep, but that it could still take several years for full regulatory approval in the U.S.

“Obviously, one of the major obstacles to overcome is the FDA approval process. The FDA is very rigorous and requires careful documentation at every phase of the preclinical and clinical testing. One of the advantages of this new material is that it is actually a new material made from two already FDA approved precursor materials. This will likely be a benefit when initiating dialogue with the FDA; in my opinion, this unique approach of combining two already approved precursors does not exactly constitute a new material in a regulatory sense,” he told ISRAEL21c.

The Technion has registered a patent on the development of Gelrin, and Seliktar says that the institute is currently in talks with an entrepreneur who has heard of the material and is interested in establishing a start-up that will develop applications for it.

Seliktar has been working on Gelrin for four years and on tissue engineering in general for a decade.

He was born in Scotland, raised in Israel until the age of 11, studied in Atlanta, and then came on aliya from Philadelphia.

Meanwhile, two hours away at the Hebrew University of Jersusalem, a novel wound dressing made of genetically engineered human collagen that will enable faster and improved healing of injuries has been developed by researchers at the Faculty of Dental Medicine.

In this effort, the protein collagen is the key innovation, rather than the standard being replaced by Gelrin.

Collagen is the most abundant protein in the animal kingdom, including humans. It is the major constituent of connective tissues – tendons, skin, bones, cartilage, blood vessel walls and membranes. Collagen fibers are the ‘warp and woof’ of these connective tissues and are responsible for keeping all the body’s organs and tissues in their correct functional structure.

There are different collagen-containing preparations on the market today made for treating wounds, for use in dentistry implants, and in cosmetics. All of them use collagen made from animal tissues, which requires specific adaptation in order to eliminate immunological rejection or to prevent microbiological infection.

The dressing developed at the Hebrew University incorporates an inner layer of genetically engineered, human recombinant collagen. This material becomes a soluble, readily enzymatically degradable molecule in the wound tissue. The molecular fragments that are thus formed have been shown to play a pivotal role in the healing process. An outer layer, also of biological origin, is provided in the wound dressing to provide initial protection prior to release of the delicate collagen layer.

Preliminary animal experiments with the new dressing have shown substantially faster and better healing, with rapid formation of new collagen fibers, than has been possible using older methods.

The new dressing is the fruit of many years of experimentation with collagen in the laboratory of Prof. Emeritus Shmuel Shoshan of the Connective Tissue Research Laboratory of the Hebrew University Faculty of Dental Medicine. Prof. Shoshan is the inventor and chief scientist of Dittekol Ltd., a company formed in cooperation with the Hebrew University’s Yissum Research Development Company, to commercialize the new wound dressing. The company is now negotiating with investors for further development.