Cells, not tools, may help fix arteries

In the past decade, artery repair has become one of the most lucrative industries in healthcare, spawning billion-dollar companies like Boston Scientific Corp. that make equipment to keep blood flowing smoothly through the body's most important vessels.

Now a small Cambridge start-up company is trying to go one better: fixing arteries and veins not with tools, but by wrapping them in a gelatinous sheath of living, healthy cells.

Pervasis Therapeutics Inc. is only now starting to test its product in humans. It hopes to finish tests in a handful of patients by the end of the year. But investors have already been attracted by the company's idea and its blue-chip scientific founders: So far, it has raised $15 million in backing from a small group of the region's top venture capitalists.

The birth of Pervasis reads like a playbook for how the closely networked Boston life-science world hatches a company. The biggest name on the door is cofounder Robert Langer of the Massachusetts Institute of Technology, perhaps the region's single most prolific biomedical inventor. He cofounded it with Joseph Vacanti , a specialist in engineering living organs, and cardiologist Elazer Edelman, of Brigham & Women's Hospital.

Edelman, now a professor at Harvard and MIT, once studied in Langer's lab, as did one of its early venture investors. Another cofounder, Helen Nugent, studied under Edelman. Langer and Vacanti, a surgeon at Massachusetts General Hospital, coauthored an influential early article on tissue engineering. And the company's first dollop of funding, $250,000, was awarded in 2002, when a professor at MIT's Deshpande Center for Technological Innovation tapped Langer on the shoulder and asked him if he had any potential companies up his sleeve.

The problem Pervasis hopes to tackle is widespread. Damage to blood vessels, whether from long-term disease or sudden injury, can cause enormous, even fatal problems.

``If you get a cut in your arm and it heals, you get a nice scar. But if you cut an artery or a vein, you get a disruption of the inside lining of the vessel," said Stephen Bolliger , the chief executive of Pervasis.

Doctors have devised numerous ways to open damaged vessels, either with drugs or with tiny mechanical tools threaded into the blood vessels themselves. Dozens of companies, including the major device manufacturers, are competing for the same prize: A way to fix damaged arteries or veins while minimizing future trouble. The field's biggest success story, the drug-coated stents that prop heart arteries open and emit a drug to keep them clear, now appear to cause troublesome side effects years after being implanted, and their manufacturers are all racing to find the next idea.

The solution Pervasis is trying, in Langer's words, is a ``cellular Band-aid" -- a soft wrapper lined with a healthy colony of living blood-vessel cells.

The product starts with cells harvested from the smooth inner lining of a cadaver's blood vessels. In laboratory testing, Edelman has grown them into a tiny raft of living tissue. And surprisingly, he found that they didn't need to be stuffed inside injured blood vessels to help them heal properly. Even wrapped around the outside of the artery, the cells appear to spur healing on the inner surface.

In essence, the wrap fixes arteries by rebuilding them inside-out.

The idea could have broad implications for implanting human cells to repair the body, a longstanding but elusive dream of researchers at the edge of medical technology.

``For years people have struggled with how to use cells to replace vital organs," Edelman said. If his idea works in humans, he said, it would show that you don't need to fully rebuild an organ to replace it.

``It could very well be that you could get 95 percent of the functionality that you wish, without getting anywhere close to 100 percent of the structure," he said.

The company's first trials will be on kidney patients, who often suffer serious scarring inside the vessels used for life-saving dialysis. If they succeed, future tests could include coronary bypass patients and trauma surgery.

Even if Pervasis hits its first set of goals, it will still face a tough road. The idea of growing new body parts in the lab, or ``tissue engineering," has been far richer with promise than with actual products.

Some of the problems are medical: People's immune systems tend to reject living cells that came from a stranger's body. Some are logistical: Live-cell products have a notoriously short shelf life. One of the few marketed products, a lab-grown skin replacement made by Genzyme Corp. in Cambridge, must be rushed from the factory to the operating room on an airplane.

But Pervasis says the product's shelf life is up to two weeks, and Edelman said his cells have not caused allergic reactions in the animals they've been tested on. He is careful to say that a live-cell gelatin won't be replacing artery stents any time soon, but if the company can solve some of the problems that have plagued tissue engineering, its use could eventually stretch far beyond the bloodstream.

Stephen Heuser can be reached at sheuser@globe.com.