COOLING PROTECTS THE CNS BY MODULATING INFLAMMATION
W. Dalton Dietrich, Ph.D. • Robert P. Yezierski, Ph.D.

Scientific Director, Dr. W. Dalton Dietrich, and his colleagues are exploring the use of moderate cooling (hypothermia) after traumatic injury to protect the central nervous system (CNS). They have shown that cooling the brain by about five degrees substantially decreases the amount of damage. Collaborating with Dr. Robert Yezierski, he is also exploring spinal cord injury (SCI). New research shows that cooling the nervous system can protect after SCI as well. The question is how does cooling help?
The researchers have looked at how the immune system’s reaction to the injury is affected by temperature by measuring enzymes that reflect the activity of white blood cells known as “polymorphonuclear leukocytes.” Their studies show that, compared to rats with normal body temperatures (37O C), cooled animals have less evidence of immunological reaction after brain or spinal cord injury. Conversely, animals with hyperthermia (fever-like temperatures) had significantly higher immune reactions, and more severe brain injury.

The reaction of the white blood cells at different temperatures suggests that suppressing damaging immunological reactions may explain the neuroprotective effects of cooling after injury to the brain and spinal cord. Neuroprotective strategies, including hypothermia, are now being tested in combination with grafting strategies being designed to improve nerve regeneration and recovery from chronic injuries as well.