It is known that in severe acquired brain injuries there is process of neuroinflammation, with the activation of a local and general stress response. In our study we considered six patients with disorders of consciousness (five in vegetative state and one in minimal consciousness state) in subacute phase, which had both a clinical assessment and a functional imaging (fMRI): in all these patients we analised blood levels of osteopontin (OPN), a cytokin involved in neuroinflammation but also in neurorepair with a still discussed role. Besides we studied the lymphocyte subsets and blood levels of some hormones (ADH, ACTH, PRL, GH, TSH, fT3, fT4). We found a positive correlation between the levels of serum osteopontin (higher than normal in all subjects) and the severity of the brain injury, especially for prognosis: actually, the patient with the lowest level has emerged from minimal consciousness state, while the one with the highest level has died a few days after the evaluation. The lymphocyte subset was altered, with a general increase of CD4+/CD3+ ratio, but without a so strict correlation with clinical severity; the only hormone with a significant increase in the worse patients was prolactin. In fMRI we detected some responses to visual and acoustic stimuli also in vegetative states, which had no clinical response to this kind of stimulation but generally have had a better prognosis. So we conclude that osteopontin could be a good marker of neuroinflammation and relate to a worse prognosis of brain injuries; the lymphocyte alterations in these disorders are not clear, but we suspect an unbalance of CD4 towards Th2; PRL is the best endocrinological marker of brain injury severity; fMRI surely plays an important role in the detection of subclinical responses and in prognostic stratification, that is still to define with more studies and statistical analysis.
Keywords: Osteopontin, vegetative, fMRI.