High-Frequency Spinal Stimulation Suppresses Microglial Kaiso-P2X7 Receptor Axis-Induced Inflammation to Alleviate Neuropathic Pain in Rats.

OBJECTIVE: Neuropathic pain poses a persistent challenge in clinical management. Neuromodulation has emerged as a last-resort therapy. Conventional spinal cord stimulation (Con SCS) often causes abnormal sensations and provides short analgesia, whereas high-frequency spinal cord stimulation (HF SCS) is a newer therapy that effectively alleviates pain without paresthesia. However, the modes of action of 10kHz HF SCS (HF10 SCS) in pain relief remain unclear. To bridge this knowledge gap, we employed preclinical models that mimic certain features of clinical SCS to explore the underlying mechanisms of HF10 SCS. Addressing these issues would provide the scientific basis for improving and evaluating the effectiveness, reliability, and practicality of different frequency SCS in clinical settings. METHODS: We established a preclinical SCS model to examine its effects in a neuropathic pain rat model. We conducted bulk and single-cell RNA sequencing in the spinal dorsal horn (SDH) to examine cellular and molecular changes under different treatments. We employed genetic manipulations through intrathecal injection of a lentiviral system to explore the SCS-mediated signaling axis in pain. Various behavioral tests were performed to evaluate pain conditions under different treatments. RESULTS: We found that HF10 SCS significantly reduces immune responses in the SDH by inactivating the Kaiso-P2X7R pathological axis in microglia, promoting long-lasting pain relief. Targeting Kaiso-P2X7R in microglia dramatically improved efficacy of Con SCS treatment, leading to reduced neuroinflammation and long-lasting pain relief. INTERPRETATION: HF10 SCS could improve the immunopathologic state in the SDH, extending its benefits beyond symptom relief. Targeting the Kaiso-P2X7R axis may enhance Con SCS therapy and offer a new strategy for pain management. ANN NEUROL 2024;95:966-983.

Neuronavigation-guided Percutaneous Rhizotomies to Trigeminal Neuralgia: A Systematic Review.

OBJECTIVE: Neuronavigation improves intraoperative visualization of the cranial structures, which is valuable in percutaneous surgical treatments for patients with trigeminal neuralgia (TN) who are refractory to pharmacotherapy or reluctant to receive open surgery. The objective of this review was to evaluate the available neuronavigation-guided percutaneous surgical treatment modalities with cannulation of foramen ovale to TN, and their relative benefits and limitations. METHODS: This review was conducted based on the PRISMA statement. An initial search was performed on electronic databases, followed by manual and reference searches. Study and patient characteristics, rhizotomy procedure and neuronavigation details, and treatment outcomes (initial pain relief and pain recurrence within 2 y, success rate of forman ovale cannulation, and complications) were evaluated. The risk of bias was assessed with a quality assessment based on the ROBINS-I tools. RESULTS: Ten studies (491 operations, 403 participants) were analyzed. Three percutaneous trigeminal rhizotomy modalities identified were radiofrequency thermocoagulation rhizotomy (RFTR), percutaneous balloon compression, and glycerol rhizotomy. Intraoperative computed tomography and magnetic resonance imaging fusion-based RFTR had the highest initial pain relief rate of 97.0%. The success rate of foramen ovale cannulation ranged from 92.3% to 100% under neuronavigation. Facial hypoesthesia and masticatory muscle weakness were the most reported complications. DISCUSSION: Neuronavigation-guided percutaneous trigeminal rhizotomies showed possible superior pain relief outcomes to that of conventional rhizotomies in TN, with the benefits of radiation reduction and lower complication development rates. The limitations of neuronavigation remain its high cost and limited availability. Higher-quality prospective studies and randomized clinical trials of neuronavigation-guided percutaneous trigeminal rhizotomy were lacking.

Intrinsic and extrinsic actions of human neural progenitors with SUFU inhibition promote tissue repair and functional recovery from severe spinal cord injury.

Neural progenitor cells (NPCs) derived from human pluripotent stem cells(hPSCs) provide major cell sources for repairing damaged neural circuitry and enabling axonal regeneration after spinal cord injury (SCI). However, the injury niche and inadequate intrinsic factors in the adult spinal cord restrict the therapeutic potential of transplanted NPCs. The Sonic Hedgehog protein (Shh) has crucial roles in neurodevelopment by promoting the formation of motorneurons and oligodendrocytes as well as its recently described neuroprotective features in response to the injury, indicating its essential role in neural homeostasis and tissue repair. In this study, we demonstrate that elevated SHH signaling in hNPCs by inhibiting its negative regulator, SUFU, enhanced cell survival and promoted robust neuronal differentiation with extensive axonal outgrowth, counteracting the harmful effects of the injured niche. Importantly, SUFU inhibition in NPCs exert non-cell autonomous effects on promoting survival and neurogenesis of endogenous cells and modulating the microenvironment by reducing suppressive barriers around lesion sites. The combined beneficial effects of SUFU inhibition in hNPCs resulted in the effective reconstruction of neuronal connectivity with the host and corticospinal regeneration, significantly improving neurobehavioral recovery in recipient animals. These results demonstrate that SUFU inhibition confers hNPCs with potent therapeutic potential to overcome extrinsic and intrinsic barriers in transplantation treatments for SCI.

Comparison of the effects of sufentanil-dominant anaesthesia/analgesia and epidural anaesthesia/analgesia on postoperative immunological alterations, stress responses and prognosis in open hepatectomy: a randomized trial.

Background: Both in vitro and in animal studies have shown immunosuppressive effects of opioids which might provoke tumour growth and metastasis, while no definite results were shown in previous clinical studies. To find out the effects between general anaesthesia combined with sufentanil target-controlled infusion (SGA) and general anaesthesia combined with epidural anaesthesia (EGA) on immunological alterations, stress responses and prognosis in patients undergoing open hepatectomy, a prospective, non-inferiority, randomized-controlled study was performed. Methods: Patients with liver neoplasms undergoing open hepatectomy were randomly assigned to either SGA (n=81) or EGA (n=81) group. The primary outcome was the ratio of interferon (IFN)-γ/interleukin (IL)-4 at 24 h after surgery (T3). The secondary outcomes included immune-related cytokines, circulating immune cells, stress-related cytokines, cortisol and blood glucose, visual analogue scale scores. Plasma was sampled at five-time points [baseline/before surgery (T0), 5 min after portal block release (T1), 1 h after surgery (T2), T3, and on a postoperative day (POD)5 (T4)]. Cancer-related outcomes, including recurrence, metastasis and survival, were followed up at 3 months and 1 year after surgery. Results: The IFN-γ/IL-4 ratios were comparable between both groups at T3 {median [interquartile range (IQR)]: 20.78 (12.73-29.18) vs. 19.52 (13.98-29.29), P=0.607}. At T3, the proportions of circulating T cells were decreased, while those of B and natural killer cells were increased. The plasma level of tumour necrosis factor (TNF)-α at T2 was significantly higher in the SGA group [median (IQR): 7.45 (6.20-9.80) vs. 5.95 (4.95-7.45) pg/mL, P<0.001]. Patient-controlled intravenous analgesia was less effective than epidural analgesia on POD0 and POD2. For hepatocellular carcinoma (HCC)-related outcomes, no significant differences were found in either short- or long-term follow-ups. Conclusions: Although the levels of TNF-α were higher in the SGA group, the tumour-related immunological alterations and follow-ups showed no difference between groups. SGA appears not to be inferior to EGA regarding tumour-related immunity and prognosis. Intravenous opioid use appears not to be inferior to epidural anaesthesia, and can be used safely in HCC patients without worsening patients' prognosis. Trial Registration: Chinese Clinical Trial Registry (No. ChiCTR2000035299).