"When a patient has high cholesterol, you can monitor their risk for heart disease and response to therapy with a blood test. With sickle cell disease, despite patients having the same underlying genetic change, some suffer tremendously while others don't and we still don't have a test that can guide physicians in making therapeutic decisions," Bhatia says.
In 2007, Bhatia and L. Mahadevan, a Harvard professor of applied mathematics who studies natural and biological phenomena, started working together to understand how sickle cells move through capillaries. In the current study, the researchers recreated the conditions that can produce a vaso-occlusive crisis: They directed blood through a microchannel and lowered its oxygen concentration, which triggers sickle cells to jam and block blood flow.
For each blood sample, they measured how quickly it would stop flowing after being deoxygenized. John Higgins of MGH and Harvard Medical School, an author of the paper, compared blood samples taken from sickle cell patients who had or had not made an emergency trip to the hospital or received a blood transfusion within the previous 12 months, and found that blood from patients with a less severe form of the disease did not slow down as quickly as that of more severely affected patients.
No other existing measures of blood properties including concentration of red blood cells, fraction of altered hemoglobin or white blood cell count can make this kind of prediction, Bhatia says. The finding highlights the importance of looking at vaso-occlusion as the result of the interaction of many factors, rather than a single molecular measurement, she says.
|Contact: Kimberly Allen|
Massachusetts Institute of Technology