If similar effects are found in humans, and its use is properly timed, then giving erythropoietin early could slow loss of healthy blood vessels in retinopathy, says Smith. "Right now, there is very little out there to treat blood vessel loss in patients with retinopathy. However, further studies on the restoration of normal levels of erythropoietin are needed to translate these results to patients."
In other diseases, like cancer, in which doctors need to slow blood vessel growth, the hormone could be blocked, although clinical trials would need to confirm this idea, she adds.
But given at the wrong time, erythropoietin may make blood vessels grow in an unhealthy way, says Smith. For example, because it boosts red blood cells, erythropoietin is often prescribed to premature babies and diabetic adults for anemia. Some of these patients also have retinopathy. Giving the hormone at the wrong time might help anemia, but worsen the eye disease.
"We're not saying, 'don't do it.' We're saying, 'think about it,'" says Smith. "Physicians should look at the state of the eye before giving erythropoietin to patients with retinopathy. They should consider not giving it to patients with full-blown retinopathy, in which abnormal vessels are present, because our work suggests it may accelerate the disease. However, if a patient is early on in the disease, then our work suggests erythropoietin may be beneficial."
Cancer patients, who often take erythropoietin for anemia, face a similar potential risk, says Smith. "Since erythropoietin has the potential to make blood vessels in tumors grow, it could make tumors worse, although a clinical trial is required to know if this is true in humans."
Overall, Smith says her mouse studies are a reason for doctors to think and researchers to investigate, not for pat
|Contact: Keri Stedman|
Children's Hospital Boston