The main goal of this phase 1 clinical trial was to evaluate the safety of an autologous mesenchymal stem cell (MSC) application as therapy for drug-resistant symptomatic epilepsy in a one-center study. It is well known that drug-resistant symptomatic epilepsy is a dramatically invalidating disorder for which applied stationary and outpatient therapies have no real clinical effect. Therefore new approaches are needed to reach remission, to stop disease progression, and to increase patient quality of life. For this study, adult (18-60 years old) patients (pts) of both sexes suffering from drug-resistant symptomatic epilepsy with frequent (\>5 events per month) seizures were included into study. Drug-resistance was defined by a lack of any evident clinical response (i.e., no decrease in seizure frequency or reduction in disease progression) of the pts with symptomatic epilepsy to carbamazepine, valproic acid, topiramate, lamotrigine, or phenobarbital (i.e., anti-epileptic drugs\[AEDs\]) as monotherapies and in different combinations over the previous one calendar year. The criteria for exclusion were patient refusal to participate, unfavorable reactions to therapy, CNS inflammatory conditions, chronic psychoses, CNS tumors, relapses of chronic somatic or neurologic diseases, and blood positivity for hepatitis B or C or HIV. The plan included the inclusion of 30 pts in the study group and 30 pts in the control group over a period of 5 years. The pts were randomized to standard treatment with AEDs (control group) or AEDs plus autologous mesenchymal stem cells (MSCs, study group). The MSCs were obtained from bone marrow samples of the same patient and were purified and expanded ex vivo in a specialized cellular biotechnology laboratory. The MSCs were characterized by immunophenotyping as CD90+CD105 +CD45-CD34-cells. After 3 weeks of cultivation in vitro, a portion of the MSC were additionally cultured for 7 days in Neurocult-XF proliferation medium to obtain neuroinduced MSCs. Neuroinduction was proved by the presence of the genetic markers nestin and neuron-specific enolase. Finally, 40-101 x 106 autologous cultured MSCs and 2.7 - 8.0 x 106 autologous neuroinduced MSCs were harvested, resuspended in saline solution containing 5% autologous blood serum for injection, and, following a measurement of the viability (98% cells), transferred to the clinical center.

The pts in the study group received one slowly delivered (over 5-10 minutes) intravenous injection of ex vivo expanded autologous MSCs in a volume of 20 ml, and 5-7 days later, each patient in the study group received an additional slowly delivered endolumbal injection of the neuroinduced MSCs in a volume of 5 ml. Both unfavorable reactions to the MSC injections (over one day following the performance of the procedures) and the early (up to one month) and late (up to 6 months) clinical effects, including complications, were evaluated. Unfavorable reactions to the MSC injections included local pain or hemorrhage at the site of injection and systemic reactions of the central nervous system (CNS, i.e., hyperthermia, fatigue, and myalgia). Later potential unfavorable systemic reactions of the CNS and vascular system, including infectious and noninfectious complications of the progression of the disease to be controlled, were examined. All of the events were documented in medical cards. In cases in which these events exhibited dangerous characteristics, they were declared to members of the monitoring board (the center's ethical committee) for the evaluation of the exclusion of the patients from the study or the termination of the clinical study.

Also evaluated were the possible beneficial effects of MSC-based therapy in the pts of the study group. These effects were detected via clinical observations at selected therapy time points (i.e., 3 and 12 months after the application of the MSC-based therapy) and electroencephalography measurements prior to and one year after the therapy. To determine the possible changes in disease progression, signs of cognitive impairment, behavioral disorders, and changes in seizure characteristics and frequency were evaluated. For the evaluation of cognitive impairment, we used the Mini-Mental State Examination. The handicapping effect of disease on daily life was scoring using the Subjective Handicap of Epilepsy Scale. State anxiety and depression were evaluated using the Hospital anxiety and depression scale . Changes in seizure characteristics and frequency were evaluated using the National Hospital Scale of Seizure Severity. The processes of voluntary attention and performance were studied with Schulte tables according to the methods of Kraepelin. Schulte tables were used to study sensorimotor reaction times and the distribution and stability of attention. The "Account of Kraepelin" method was used to study health, fatigue and the stability of attention. The assessment of short-term memory was performed via the method of memorizing 10 words; this method aims to determine the volume and speed of oral-aural memory.

Main clinical characteristics that are used for disease monitoring were "yes" or "no" responses (regarding therapy), seizure frequency (per month), and remission of disease at the early (3 months) and late (12 month and more) time points after therapy. To evaluate partial responses to therapy, the numbers of pts who exhibited 50% reductions in seizure frequency were assessed. Seizure type (i.e., generalized tonic-clonic, partial complex, simple partial, and multiple types of seizures) was also evaluated along with changes in seizure type during the treatment course.

Electroencephalography recordings were performed at admission and across the monitoring period using a Mizar EEG 201 encephalography system with biopotential registration from 16 body points according to the "10-20" scheme. The observed electrical alpha, beta, theta and delta waves were analyzed in 3-min segments (with further recalculation for each 1-minute segment) prior to (at admission) and 1 year after MSC application. The peak frequency of the alpha waves was also calculated. Both the spontaneous state and the state after the loading probe (hyperventilation and photostimulation) were evaluated for each patient. The characteristics of the electroencephalographies (EEG) were attributed to local and diffuse cortical alterations. We evaluated the paroxysmality index, quantities of local and generalized spikes of epileptiform waves per minute, peak frequency of EEG activity, index of slow activity, and summarized points of EEG pathology signs. EEGs with epileptiform activity included spikes, spike-slow waves, and high-amplitude spikes. The EEG recordings were performed based on standard and additionally proposed criteria . All of the assessments were performed for the pts in the control and study groups, and the obtained data were compared to determine the potential differences due to the additionally performed MSC-based therapy. A patient's therapy was terminated at any time point if immediate unfavorable reactions to the MSC injections were observed. The final observations of the patients included clinical and EEG assessments at 12 months (or more) after the application of the MSC-based therapy. The summarized data for the pts in the control and study groups were collected in an electronic database for further analysis and interpretations.