Breakthroughs Offer Promise for Cardiovascular Disease

MU researcher Mark Haidekker tests a method to monitor living vascular grafts from patient's cells.

Scanning blood vessels (WMV)

Breakthroughs in tissue-engineered blood vessels grown from a patient's own cells offer promise for those suffering from cardiovascular diseases, particularly arteriosclerosis.

Using the patient's own cells to create a vessel graft prevents reaction problems associated with synthetic materials, which can cause inflammation, infection and ultimately rejection.

Such lab-grown vessels also may help heart patients who need a blockage bypass but do not have suitable vessels from other parts of their body.

A difficulty with this natural vessel graft is ensuring the tissues are of high quality before physicians insert them into the patient. Synthetic materials can be manufactured to careful specifications.

Growing cells into tissue that is homogenous and healthy isn't as easy, said Mark Haidekker, University of Missouri biological engineering researcher, who is testing two monitoring methods.

To create natural-tissue vessels, scientists collect cells from the patient's skin and inner lining of blood vessels. These cells are grown into sheets, wrapped in a medical tube and fused together to form a vessel, said Todd McAllister of the California-based Cytograft Tissue Engineering firm.

Monitoring the quality of the growing cells during this sheet and roll stage, without damaging the cell sheet in the process, is essential, he said.

Haidekker, funded by a National Institute of Health grant, is developing and comparing two noninvasive imaging methods to check the effectiveness of these vascular grafts.

"Unlike with synthetic grafts, mechanical testing of these biological grafts is costly and not very effective," he said. "There is a growing demand for noninvasive methods to predict biochemical properties."

Haidekker is testing transillumination optical tomography (OT) and optical coherence tomography (OCT). "I am essentially putting two horses to a race," he said. "We will see in the end which one performs better."

An OT is basically a CAT scan that uses lasers rather than x-rays. The OCT is what Haidekker calls the optical equivalent of an ultrasound device.

The process of growing a sheet of cells requires several weeks after the patient provides a skin biopsy.

"Our vision is that we can take a sample out of the incubator and examine it on a daily basis so that we not only have a one-time examination but a record of development," he said.

A third component of the research is to integrate a monitoring system into the actual manufacturing process. This would involve an on-site device that would monitor the vessel inside the sterile growth container rather than having to remove the vessel for examination.

Engineered tissue vessels are being tested with patients undergoing regular dialysis for end-stage kidney disease and may also help salvage lower limbs, reducing the number of amputations, Haidekker said. The MU researcher has worked in a number of projects developing non-invasive ways to peer into the human body.