Effects of hematopoietic autologous stem cell transplantation to the chronically injured human spinal cord evaluated by motor and somatosensory evoked potentials methods.

International standards for stem cell treatment of neurological disorders have not yet been established. In particular, specific quantitative methods have not yet been adopted to assess the effectiveness of stem cell treatment. The aim of this study is to evaluate the functional changes detectable by conventional neurophysiologic methods in an injured spinal cord during stem cell therapy. Twenty adult patients with chronic spinal cord injury at C4-C8 level were examined by somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) methods, the first time prior to the treatment and then regularly during its course (1-4 years). The treatment consisted of repeated intrathecal transplantations of autologous hematopoietic stem cells. After at least 1 year of treatment, four effects were detected: 1) restoration of the initially absent short-latency SEP (three patients); 2. N20P23 interpeak amplitude increase in SEP elicited by median nerve stimulation (four patients); 3) P38 latency reduction in SEP elicited by tibial nerve stimulation (two patients); 4) appearance of MEP (three patients). The nonidentical effects of stem cell transplantation in different patients presumably reflect the variety of the regeneration processes in different pathways of the spinal cord, depending on the extent and nature of lesion of the spinal cord pathways in different patients. The local effects of stem cell treatment at the cervical level were evaluated by median SEP and wrist muscle MEP demonstrate the ability of stem cells to spread within the spinal cord at least from lumbar to the cervical level, home there, and participate in the neurorestoration processes.