Evaluation of apoptosis in cerebrospinal fluid of patients with severe head injury

To determine whether sFas, caspase-3, proteins which propagate apoptosis, and bcl-2, a protein which inhibits apoptosis, would be increased in cerebrospinal fluid (CSF) in patients with severe traumatic brain injury (TBI) and to examine the correlation of sFas, caspase-3, and bcl-2 with each other and with clinical variables.

sFas, caspase-3, and bcl-2 were measured in CSF of 14 patients with severe TBI on days 1, 2, 3, 5, 7, and 10 post-trauma. The results were compared with CSF samples from control patients who had no brain and spinal pathology and had undergone spinal anesthesia for some other reason. Soluble Fas and bcl-2 were measured by ELISA while caspase-3 was measured enzymatically.

No sFas, caspase-3, and bcl-2 activities were found in CSF of controls, but activities significantly increased in CSF of patients at all time points post-trauma (p < 0.01). Caspase-3 significantly correlated to intracranial pressure (p = 0.01) and cerebral perfusion pressure (p = 0.04). Soluble Fas and caspase-3 peaks coincided on day 5 post-trauma and there was significant association between sFas and caspase-3 increase (p = 0.01).

This study indicates a prolonged activation of pro-apoptotic (sFas, caspase-3) and anti-apoptotic (bcl-2) proteins after severe TBI in humans. The degree of activation of particularly caspase-3 may be related to the severity of the injury. Parallel increases of these three molecules may indicate a pivotal role of apoptosis in the pathophysiology of post-traumatic brain oedema, secondary cell destruction and chronic cell loss following severe TBI and may open new targets for post-traumatic therapeutic interventions.