Experimental umbilical cord stem cell therapy treats rare disease

By Clare Wilson

A girl who was critically ill with heart failure is doing well after receiving an experimental treatment made from umbilical cord stem cells, in the first case of its kind.

The girl, from Germany, has an inherited form of pulmonary arterial hypertension. Defined as high blood pressure in the arteries of the lungs, this meant the blood vessels of her lungs were malformed, which leads to progressive and usually fatal heart failure. Now six, doctors recommended she have a lung transplant at three years old, a procedure that is usually carried out on children who have less than a year to live.

In the experimental treatment, Georg Hansmann at Hannover Medical School and his colleagues harnessed stem cells from her sister’s umbilical cord, which her parents gave permission to be frozen.

The cells were grown in a dish. Periodically, the nutrient liquid they were bathed in was changed and the old liquid was stored. Three years ago, once enough liquid had accumulated, it was infused into blood vessels in the girl’s lungs and heart over six months.

The girl, who was previously breathlessness at rest and could only walk slowly, gradually improved over the following months. She now has no limitations in her exercise capacity. She also grew 10cm within the first three months of treatment, having previously had no growth in height or weight in the preceding year.

Many measurements of her heart and lung function have also shown improvements. However, she still has high blood pressure in her lungs and may need further treatment, says Hansmann.

Stem cells have the potential to grow into different kinds of tissue and are being tested in many experimental treatments, for instance for kidney or liver failure. They can be obtained in small quantities from various parts of the body and made in the laboratory from ordinary skin cells.

Stem cell treatments usually involve putting the cells into someone’s body, which can cause immune reactions. In the girl’s case, the cells were not transplanted, but grown in a dish, where they released biochemicals that seem to promote the healing of other tissues into the nutrient liquid they are bathed in.

Her treatment used mesenchymal stem cells, which are involved in the making and repairing of skeletal tissues. These cells were previously tested as way of repairing heart muscle damaged by heart attacks, but did not lead to lasting benefits and studies found no trace of the transplanted cells in the heart muscle.

But some recipients had short-term improvements, suggesting that the cells released signalling chemicals that promote healing, an idea supported by various animal studies.

The team behind the girl’s treatment has not yet carried out imaging procedures to visualise her lung blood vessels. These procedures can be risky, particularly given her condition.

The girl also received two standard medicines for her condition before the stem cell treatment, which may have contributed to her improvement, says Martin Wilkins at Imperial College London.

When Hansmann’s team investigated samples of the stem cell liquid the girl received, they found high levels of several biochemicals that are thought to promote healing and regeneration, while suppressing inflammation, including the biochemical prostaglandin E2.

Prostaglandin E2 tends to be broken down in the body quickly, so other unknown compounds may be having an effect, says Wilkins. “This is not a treatment we can rush out to other patients until we better understand the mechanism,” he says.

“There does appear to have been an improvement both in her biochemical [measurements] and in her functional capacity. It’s reasonable to assume there’s something going on here that’s of interest.”

Journal reference: Nature Cardiovascular Research, DOI: 10.1038/s44161-022-00083-z