Monday, November 26, 2012

Changes in spleen size

International Journal of Stroke Managing Editor spoke to Drs. Sean Savitz and Farhaan Vahidy on the eve of the online publication of this very novel study. You can download this interview here. 

The spleen in stroke patients undergoes dynamic changes of contractions and re-expansion in the days following the onset of stroke symptoms, releasing inflammatory cells and contributing to further brain injury, according to researchers at The University of Texas Health Science Center at Houston (UTHealth) Medical School.

“We’ve known from animal studies that the spleen contracts after stroke, followed by the release of inflammatory white blood cells leading to secondary brain injury, so we wanted to observe what happens to the spleen in patients after a stroke,” said Sean I. Savitz, principal investigator and professor of neurology at the UTHealth Medical School. 

Photo credit: NIH
“This is a completely understudied area. The spleen is not normally an organ that neurologists or neuroscientists pay attention to. This was our initial attempt to look at the size of the spleen in stroke patients.”

The spleen is part of the lymphatic system, which fights infection by releasing white blood cells. It also helps control the amount of blood in the body and destroys old and damaged cells.

The study included 29 stroke patients and 20 healthy volunteers. The research team performed daily abdominal ultrasounds to measure the size of the spleens. In the stroke patients, spleens initially reduced in size and then re-expanded. The spleens of the healthy volunteers showed minimal variation in daily spleen size compared with the stroke patients.
Savitz said the study demonstrated a good correlation between the contraction of the spleen and the amount of white blood cells in the body. The results also suggested that some patients whose spleens contracted for a longer period of time, releasing more inflammatory white blood cells, had poorer clinical outcomes. Further studies will be needed to confirm and explain these early findings, Savitz said.

Savitz and fellow researchers became interested in studying the spleen after animal studies at UT-Health and elsewhere showed that stem cells administered intravenously after a stroke travelled to the spleen, as well as to the brain.

“The big question was why,” said Savitz, who is director of the Stroke Program at UTHealth and an attending physician at Memorial Hermann-Texas Medical Center. “Emerging work by our group and other researchers suggest that some types of stem cells have a dampening effect on the inflammatory response emanating from the spleen. The spleen is a possible target in the future for treating stroke.”
Savitz’s research team at UTHealth included first authors Preeti Sahota, M.D., and Farhaan Vahidy, M.D. 

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