Stroke, illustration

Preliminary research from the National Institute of Neurological Disorders and Stroke (NINDS), a division of the NIH, showed that bone marrow transplants prevented or improved blood vessel disease in the brains of adults with sickle cell disease.

The research will be present next week at the American Stroke Association’s International Stroke Conference 2023, held in Dallas and virtually Feb. 8-10.

“Sickle cell disease is a group of inherited disorders caused by mutations in hemoglobin and is a major risk factor for stroke in children and adults,” said the study’s lead author John K. Lynch, DO, MPH, an associate research physician in the Stroke Branch at NINDS. “The two main brain blood vessel complications of sickle cell disease are vasculopathy—where some vessels may become enlarged like an aneurysm, or some vessels may narrow and block; silent brain injuries can occur throughout the brain as a result of vasculopathy.”

A major cause of death and disability in children and adults with sickle cell disease is stroke, and that can be caused by either abnormal bulging, or narrowing, of blood vessels in the brain. The researchers—who recognized the promise of bone marrow transplants from previous studies in children—sought see what effects bone marrow transplantation might have on the development and progression of vasculopathy in adults with sickle cell disease.

The investigators used an NIH study population of adults with sickle cell disease who received bone marrow transplants from 2004 to 2019 and received both pre-operative and post-operative MRI/MRA imaging. The cases were reviewed by two independent imaging professionals who scored each patient for narrowing vessels in eight arteries of the brain and any presence of aneurysms. The team then compared the changes in blood vessels from before and after bone marrow transplants in 87 people, during a follow up period of three years. 58% of the study participants were men, with an average age of 32 years.

Of the 87, 28% showed evidence of blood vessel issues in the brain (17% had narrowing of the blood vessels and 13% had bulging vessels) that were present at the time they received the bone marrow transplant. A similar comparison of patients without blood vessel abnormalities showed that none of the participants developed narrowing or bulging vessels after transplantation. Post operative brain imaging showed that narrowing of blood vessels was not only halted, but improved in 62% of the patients.

“We were surprised that bone marrow transplant reversed some of the changes in brain vessels. We thought that bone marrow transplantation would stop the changes from getting worse, however, we did not think it would reverse the changes,” Lynch said. “We suspect that the reduction in the number of sickle cells and the improvement of the cells’ oxygen-carrying capacity led to a reduction in the number of strokes after bone marrow transplantation.”

The researchers did note a couple of limitations to the study including that it did not have a comparison group of patients who did not received a transplant, as well varying times of following patients—some were followed for long periods than others.

“We would need a more uniform follow-up time for all study participants to help us understand if it takes time for the vasculopathy to stop or get better, or if this happens quickly,” Lynch said.

Also of Interest