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A 60-year-old who gardens all summer, golfs into October and hits the slopes in winter might be expected to sport the chiselled jawline of a man half his age.

But the jowl of Peter Russel is even younger than that. In fact, the silver-haired retired banking executive grew it himself just two years ago.

Like a salamander that can sprout itself a new tail, Mr. Russel has regrown seven centimetres of bone along the bottom right of his jaw, tissue he lost to a benign tumour in 2003.

“I've counted my blessings and moved on,” the dapper Mr. Russel said this week as he raised a glass of red wine to his revolutionary treatment.

He is one of eight patients in Canada who has quietly undergone a method of bone regeneration that could literally change the face of reconstructive surgery.

Using a protein that can seduce adult stem cells into becoming bone tissue, Cameron Clokie, head of oral and maxillofacial surgery at the University of Toronto, has pioneered a technique to reset the jaw's skeletal clock — coaxing bones to grow as they do in a newborn baby.

“This is pretty much back to the embryonic state of bone generation,” Dr. Clokie said. “With this patient we've actually regrown a jawbone that is identical [to the one] he lost.”

The procedures, performed at Toronto General Hospital and Mount Sinai Hospital, are a significant milestone for researchers long chasing the dream of tissue regeneration. Current methods of rebuilding body parts usually rely on the painful process of stealing bone, fat and muscle from one site to fill gaps in another.

Twenty-year-old Janine McFarlane knows this too well. As with Mr. Russel, a benign tumour swelled from the right side of Ms. McFarlane's jaw two years ago. Left untreated, the rare and aggressive jaw-tissue growth, known as ameloblastoma, can balloon to distort the face and fill the airways until it chokes a patient to death.

But unlike Mr. Russel, Ms. McFarlane, who was not a candidate for the new method because her larger tumour also involved the joint, underwent traditional surgery. In her case, surgeons replaced the jaw tissue she lost with 12 centimetres of bone carved out of her shin: “I couldn't walk for two months,” said Ms. McFarlane, an aspiring singer.

Dr. Clokie, who presented both cases at a U of T conference this week on regenerative medicine, said Ms. McFarlane's case involved a 19-hour operation and two weeks in hospital, one of them in the intensive care unit. In January, she faces a second operation in which surgeons plan to use bone from her hip to further build up her mandible so that dentists can implant false teeth.

In contrast, Mr. Russel underwent a four-hour operation that left him with little more than a faint scar, and he spent just two nights in the hospital: “Two weeks later, I was skiing in Colorado,” he said. The only lingering effect Mr. Russel described is numbness in his lower lip and chin due because a sensory nerve had to be cut to remove the tumour. “It's been amazing.”

To reconstruct Mr. Russel's jaw, Dr. Clokie added a particular growth protein to a putty-like gel that actually liquefies in the freezer and solidifies in warmer temperatures. He then modelled it into the shape of Mr. Russel's missing jaw piece. “You can imagine what it's like trying to model a [jaw] shape from bone . . . it's like wood,” Dr. Clokie said. “This is like Play-Doh.”

The gel model was then placed to fill the missing section in Mr. Russel's jaw, which was supported by the implanting of a titanium rod. Five days later, as blood vessels started growing over the gel structure, the gel itself began to dissolve. At the same time, the jawbone began to regrow to close the gap.

“This is a true example of regenerative medicine,” Dr. Clokie said.

U of T researcher Molly Shoichet, who holds the Canada Research Chair in Tissue Engineering, said: “It's an important innovation. I mean that's a lot of bone grown there.”

Dr. Shoichet noted that Mr. Russel still requires a metal rod for proper movement of his jaw, but said the technique is a definite advance.

But for now it's one that doesn't come cheap.

The protein needed to trigger bone regeneration for the procedure generally costs more than $6,000, a fee medicare doesn't cover. As Mr. Russel, who retired in 2000 at age 55, put it: “I've been lucky in my life and was able to afford it.”

He was concerned about the possible side effect of having the protein result in uncontrolled bone growth, but felt “it was worth the gamble.”

The protein, known as bone morphogenetic protein, or BMP, was discovered at the University of California at Los Angeles in the 1950s. Marshall Urist, a renowned orthopedic surgeon under whom Dr. Clokie worked for four years, found it and other growth-inducing proteins within the bone's own matrix.

Dr. Urist, who died in 2001, used BMP to foster the regrowth of the long bones found in limbs, Dr. Clokie said. Most famously, he used it to counter bone loss around the teeth of singer Dionne Warwick.

Since the late 1990s, it has also been well used in surgeries to help fuse the spine.

Along the way, research has shown BMP can affect the stem cells known to circulate in the body, even in adulthood. Those adult stem cells have the power to grow into various, though not all, human tissue types.

By the late 1990s, Dr. Clokie was determined to test BMP as a tool in reconstructive jaw surgery and discovered, “You need a whole lot of bone to derive this stuff.”

To repair the world's first jawbone with BMP, which he achieved in 1999, he had to grind the arm and leg bones of 40 cadavers to collect just three milligrams of the protein.

But since that was not an approved commercial source, Dr. Clokie later turned to a U.S. biotech firm that produces BMP in the cells of Chinese hamsters. Using that source, he has since performed the procedure, which is now also being tried by oral surgeons in South Africa, on eight men and women of all ages.

Dr. Clokie now has plans in the works to generate BMP by inserting the human gene that produces it into goat embryos. That way the goats, theoretically, could produce the protein in large quantities in their milk.

This is similar to technology developed by a Montreal biotech firm that inserted a spider-silk-producing gene into a goat embryo. That transgenic goat was then cloned into a herd to mass produce the spider-silk protein for medical and industrial uses.

“We've got to find some way to bring the costs down,” Dr. Clokie said of his ambitious intentions.