Pulmonary Hypertension Stem Cell Cure

Ivanhoe Broadcast News, October 19, 2007

Pulmonary hypertension is high blood pressure in the arteries leading to the lungs. There is no cure for the disease, but there are treatments that help to ease some of the symptoms of the disease. The vessels that carry blood from the heart to the lungs become hard and narrow in patients with pulmonary hypertension.

Over time, the heart will weaken and may result in heart failure since the condition makes it more difficult for the heart to pump blood. Available treatments for the disease range all the way to lung transplant, with oxygen therapy and drugs being less aggressive forms of therapy.

The condition is relatively rare. Among people with the disease, there were 260,000 hospital visits and 15,668 deaths in 2002. 807,000 people with pulmonary hypertension were hospitalized during the two years spanning 200 and 2002. Thirty-four percent of those hospitalizations were younger than age 65, and 61 percent were among women.

Today, their is a great deal of chatter about an innovative approach to treating pulmonary hypertension. Cell therapy is being combined with gene therapy in order to treat patients. No blood vessel or heart disease has ever been treated using combined cell and gene therapy. This approach marks a first.

Using adult stem-like cells called endothelial progenitor cells (EPC), researchers from St. Michael's Hospital in Toronto are treating patients with pulmonary hypertension. Damage occurs to the endothelial cells which line the blood vessels of the lungs in people suffering from the disease.

"The one thing that all endothelial cells have in common is that they are replaced by circulating endothelial progenitor cells. We all have in our blood a very small proportion of cells that circulate freely in our blood that have the capacity to become healthy endothelial cells when they are in the right environment. We think that those cells are there to repair blood vessels that are damaged," Dr. Michael Kutryk, from St. Michael's Hospital, said.

The EPCs are harvested from the patient's blood by doctors during the study. Endothelial nitric oxide synthase (eNOS) is a gene that is loaded into the cells. These extra copies genetically alter the cells. Maintaining healthy blood vessels is impossible without the gene eNOS. Doctors re-inject the cells into the patient after they have been genetically modified and grown in the lab. The hope is that the damage that has occurred in the patient's lung's blood vessels will be reversed by the treatment.

"It's a very, very novel and first in the world application of this technology. This will be very exciting if we can halt the progression of the disease ... we're hoping we can, in fact, reverse the disease in many cases," Kutryk said.

Treatment is being administered with increasing doses given to subsequent patients as the study is still in the early phases of testing.

"We're certainly seeing positive results at the moment, but we expect to see much better results as we increase the doses of genetically modified cells," Kutryk said.

The study is currently ongoing in Toronto and Montreal.