‘Electric’ blood vessels to help treat heart disease

AMAN-MADE ‘electronic’ blood vessel that replaces diseased arteries could transform the treatment of heart disease. the hollow implant, made of plastic mesh and metal and about the width of a straw, is packed with cells capable of growing into healthy endothelial tissue — the kind that makes up blood vessels throughout the body.

days before being surgically implanted to replace a section of diseased blood vessel, the implant is zapped with a mild electric current. the metal content acts as a conductor, allowing the current to pass through the device.

the current stimulates the dormant stem cells inside the implant to grow and spread, gradually forming healthy new blood vessel tissue around the implant. (An entirely artificial blood vessel, such as one made of plastic, would be unsuitable, as major blood vessels must be able to expand and contract in response to a change in blood pressure, for example.)

Heart disease occurs when blood vessels become clogged by deposits called plaques. in the UK, around 14,000 people a year undergo coronary artery bypass surgery, where surgeons ‘bypass’ blockages in arteries to the heart, usually with a vein harvested from another part of the body.

But up to a third of patients do not have a suitable vein for grafting, often because the veins are too unstable as a result of disease or ageing. Some patients may instead have angioplasty, where an inflatable balloon is used to clear the blocked artery by ‘squashing’ the plaque before a metal stent is implanted to prop the artery open.

this may not be suitable for patients with several blockages that can only be resolved with major bypass surgery.

in recent years, scientists have developed synthetic arteries that are seeded with stem cells (‘raw’ cells that can grow into different types of tissue) on to some kind of scaffolding material.

But in many cases the stem cells don’t grow into the tissue needed and the implant fails. the new electronic artery could be a solution as using the current starts the cell growth before the implant even goes into the body.

Scientists from the Southern University of Science and technology in Guangdong, china, and the institute of Bioengineering in lausanne, Switzerland, developed the device using three layers of mesh- like plastic sheeting rolled into a tube shape.

Between the layers are thousands of stem cells taken from human umbilical cords discarded after babies’ births. these are known to form endothelial tissue, which not only makes up blood vessels but releases substances to keep blood vessels healthy and clot-free. the mesh also contains liquid metal called gallium to conduct the electric current. Being liquid, it’s flexible enough to let the implant move with the force of the blood rushing through.

Results published in the science journal matters showed that when the implant was zapped with bursts of electric current, the number of stem cells more than doubled over the next two weeks, compared to when the cells were left to grow on their own.

the electronic artery is designed to break down inside the body over a period of months and is then flushed out as waste, leaving just healthy new tissue behind.

martin cowie, a professor of cardiology at imperial college london, said: ‘this kind of “intelligent” tissue bioengineering is showing new ways to improve blood supply in heart conditions.

‘it’s a very interesting development but early days. A lot more research is needed.’