Mesenchymal stem cells (MSCs) are considered as promising therapeutic agents for neurodegenerative disorders because they can reduce underlying pathology and also repair damaged tissues. Regarding the delivery of MSCs into the brain, intravenous and intra-arterial routes may be less feasible than intraparenchymal and intracerebroventricular routes due to the blood–brain barrier. Compared to the intraparenchymal or intracerebroventricular routes, however, the intrathecal route may have advantages: this route can deliver MSCs throughout the entire neuraxis and it is less invasive since brain surgery is not required. The objective of this study was to investigate the distribution of human Wharton’s jelly-derived MSCs (WJ-MSCs) injected via the intrathecal route in a rat model. WJ-MSCs (1 × 10⁶) were intrathecally injected via the L2-3 intervertebral space in 6-week-old Sprague Dawley rats. These rats were then sacrificed at varying time points: 0, 6, and 12 h following injection. At 12 h, a significant number of MSCs were detected in the brain but not in other organs. Furthermore, with a 10-fold higher dose of WJ-MSCs, there was a substantial increase in the number of cells migrating to the brain. These results suggest that the intrathecal route can be a promising route for the performance of stem cell therapy for CNS diseases.

Deep brain stimulation (DBS) has provided new treatment options for refractory epilepsy; however, treatment outcomes of DBS in refractory epilepsy patients previously treated with vagus nerve stimulation (VNS) have not been clarified. Herein, treatment outcomes of DBS of the anterior nucleus of the thalamus (ANT-DBS) in patients who had previously experienced VNS failure are reported. Seven patients who had previously experienced VNS failure underwent ANT-DBS device implantation. VNS was turned off before DBS device implantation. Monthly seizure counts starting from baseline to 12–18 months after DBS were analyzed. Five (71.3%) of the 7 patients experienced a >50% reduction of seizure counts after DBS; 1 responder reached a seizure-free status after DBS therapy. Of the 2 nonresponders, 1 subject showed improvement in seizure strength and duration, which lessened the impact of the seizures on the patient’s quality of life. This is the first study in which favorable outcomes of ANT-DBS surgery were observed in individual patients with refractory epilepsy who had not responded to prior VNS. Further studies with a larger number of subjects and longer follow-up period are needed to confirm the feasibility of ANT-DBS in patients who have previously experienced VNS failure.

Accurate diagnosis of trigeminal neuralgia (TN) is the starting point for optimal treatment. Gamma knife radiosurgery (GKRS) is currently regarded as one of the first-line treatment options for medically refractory TN. GKRS is a less invasive treatment with a low risk of complications than other surgical procedures that provides a favorable pain control (BNI I–IIIb) rate of >75% at short-term follow-up. Drawbacks of GKRS include the latency period before pain relief and higher recurrence rate compared with microvascular decompression. Therefore, repeat treatment is necessary if the initial GKRS was effective but followed by recurrence. The concept of dose rate and the biologically effective dose of radiation has been actively studied in radiation oncology and is also applied in GKRS for TN to achieve high safety and efficacy by prescribing the optimal dose. Recent progress in functional imaging, such as diffusion tensor imaging, enables us to understand the pathophysiology of TN and predict the clinical outcome after GKRS. Here, we review TN, GKRS, and recent updates, especially in the concepts of radiation dose, diffusion tensor imaging studies, and repeat treatment in GKRS for TN.