Polygonati Rhizoma polysaccharide suppresses microglial activation and promotes functional recovery of spinal cord via improving intestinal microbiota

Spinal cord injury (SCI) can disrupt the gut microbiome and metabolites, impacting prognosis, substantially impairing quality of life, and leading to high socioeconomic costs (Jing et al., 2021). Recent studies indicate that plant polysaccharides exhibit antimicrobial, anti-inflammatory, and immune-enhancing properties, contributing positively to various neurological disorders; however, their role in SCI remains uncertain (Hou et al., 2020 [2]; Aswini et al., 2021 [3]; Dou et al., 2019 [4]). Polygonati Rhizoma polysaccharide (PRP) has shown anti-inflammatory and immunoregulatory effects, but its role in SCI remains unexplored. This study investigated whether PRP facilitates functional recovery after SCI by modulating the gut microbiota and SCFA levels. PRP was administered to SCI mice, and motor function was assessed using DeepLabCut-based behavioral analysis. Histological evaluations were performed with H&E, Nissl, and immunofluorescence staining. Microglial activation and inflammation were analyzed by Western blot and immunofluorescence. Gut microbiota composition and SCFAs were examined through 16S rRNA sequencing and targeted metabolite profiling. PRP treatment significantly improved motor function, reduced microglial activation, and attenuated neuroinflammation. These effects were associated with restoration of microbial diversity and elevated butyrate levels. This study highlights the role of the gut-brain axis in neural regeneration and suggests PRP as a promising therapeutic candidate for SCI.

Olfactory ensheathing cells as candidate cells for chronic pain treatment

Chronic pain is often accompanied by tissue damage and pain hypersensitivity. It easily relapses and is challenging to cure, which seriously affects the patients' quality of life and is an urgent problem to be solved. Current treatment methods primarily rely on morphine drugs, which do not address the underlying nerve injury and may cause adverse reactions. Therefore, in recent years, scientists have shifted their focus from chronic pain treatment to cell transplantation. This review describes the classification and mechanism of chronic pain through the introduction of the characteristics of olfactory ensheathing cells (OECs), an in-depth discussion of special glial cells through the phagocytosis of nerve debris, receptor-ligand interactions, providing nutrition, and other inhibition of neuroinflammation, and ultimately supporting axon regeneration and mitigation of chronic pain. This review summarizes the potential and limitations of OECs for treating chronic pain by objectively analyzing relevant clinical trials and methods to enhance efficacy and future development prospects.

A Review of Treatment Methods Focusing on Human Induced Pluripotent Stem Cell-Derived Neural Stem/Progenitor Cell Transplantation for Chronic Spinal Cord Injury

Cell transplantation therapy using human induced pluripotent stem cell-derived neural stem/progenitor cells (hiPSC-NS/PCs) has attracted attention as a regenerative therapy for spinal cord injury (SCI), and its efficacy in treating the subacute phase of SCI has been reported in numerous studies. However, few studies have focused on treatment in the chronic phase, which accounts for many patients, suggesting that there are factors that are difficult to overcome in the treatment of chronic SCI. The search for therapeutic strategies that focus on chronic SCI is fraught with challenges, and the combination of different therapies is thought to be the key to a solution. In addition, many issues remain to be addressed, including the investigation of therapeutic approaches for more severe injury models of chronic SCI and the acquisition of practical motor function. This review summarizes the current progress in regenerative therapy for SCI and discusses the prospects for regenerative medicine, particularly in animal models of chronic SCI.

Clinical results of neurorestorative cell therapies and therapeutic indications according to cellular bio-proprieties

Cell therapies have been explored to treat patients with nervous diseases for over 20 years. Even though most kinds of cell therapies demonstrated neurorestorative effects in non-randomized clinical trials; the effects of the majority type cells could not be confirmed by randomized controlled trials. In this review, clinical therapeutic results of neurorestorative cell therapies according to cellular bio-proprieties or cellular functions were introduced. Currently it was demonstrated from analysis of this review that some indications of cell therapies were not appropriate, they might be reasons why their neurorestorative effects could not be proved by multicenter, randomized, double blind, placebo-controlled clinical trials. Theoretically if one kind of cell therapy has neurorestorative effects according to its cellular bio-proprieties, it should have appropriate indications. The cell therapies with special bio-properties is promising if the indication selections are appropriate, such as olfactory ensheathing cells for chronic ischemic stroke, and their neurorestorative effects can be confirmed by higher level clinical trials of evidence-based medicine.

Prospects for the use of olfactory mucosa cells in bioprinting for the treatment of spinal cord injuries

The review focuses on the most important areas of cell therapy for spinal cord injuries. Olfactory mucosa cells are promising for transplantation. Obtaining these cells is safe for patients. The use of olfactory mucosa cells is effective in restoring motor function due to the remyelination and regeneration of axons after spinal cord injuries. These cells express neurotrophic factors that play an important role in the functional recovery of nerve tissue after spinal cord injuries. In addition, it is possible to increase the content of neurotrophic factors, at the site of injury, exogenously by the direct injection of neurotrophic factors or their delivery using gene therapy. The advantages of olfactory mucosa cells, in combination with neurotrophic factors, open up wide possibilities for their application in three-dimensional and four-dimensional bioprinting technology treating spinal cord injuries.

Dopamine inhibits pyroptosis and attenuates secondary damage after spinal cord injury in female mice

BACKGROUND

An excessive inflammatory response accompanies the pathogenesis of spinal cord injury (SCI) and has been found to be promoted by inflammasomes in a variety of disease models. Dopamine is a neurotransmitter that also regulates nucleotide-binding oligomerization domain-like receptor 3 (NLRP3) inflammasome-dependent neuroinflammation. However, little is known regarding the effects and molecular mechanisms underlying the role of dopamine in SCI.

METHODS

Functional recovery in mice was assessed with the Basso Mouse Scale (BMS). Neuronal loss was evaluated with immunochemical staining of NeuN. Pyroptosis was assessed with immunofluorescence staining, flow cytometry, western blotting, and cell viability and cytotoxicity assays.

RESULTS

Dopamine was significantly associated with enhanced locomotor recovery after SCI, and with decreased NLRP3 inflammasome activation, pyroptosis, neuronal loss and pro-inflammatory cytokine levels. In vitro data suggested that dopamine suppressed NLRP3 inflammasome activation and pyroptosis, and decreased pro-inflammatory cytokine levels.

CONCLUSIONS

Dopamine may be a novel approach for alleviating secondary damage after SCI.

Recovering Voiding and Sex Function in a Patient with Chronic Complete Spinal Cord Injury by Olfactory Ensheathing Cell Transplantation

Spinal cord injury (SCI) is life-altering damage for patients, their family, and society. Transplantation of olfactory ensheathing cells has demonstrated neurorestoration effects for many neurological conditions, including SCI. But voiding and sex dysfunction in patients with chronic complete SCI is still a major issue even though neurorestorative therapies can restore their partial neurological functions. Here we report a case with traumatic complete SCI at the level of C6-C7 one year ago, who received OEC transplantation with intensive neurorehabilitation. The patient started to show clinical improvements within a few days after cell treatment. Six-year follow-up demonstrated his American Spinal Injury Association (ASIA)-Impairment Scale change from ASIA A to become ASIA C. The scores of International Association of Neurorestoratology Spinal Cord Injury Functional Rating Scale changed from 14 (prior to cell therapy) to 31 + 3 (six years after cell therapy). His main improvements in activity of daily life included eating, dressing and writing by himself, standing and walking, and urine control or voiding. His sex function recovered to be normal. He married and had a son through natural sex life. His improving functions and activities of daily life stayed stable in subsequent phone call follow-up. This was one individual case report. In the future, the deep mechanisms of why he got positive results, but other patients with similar condition did not get so much benefits from OEC transplantation should be explored.

Topoisomerase 1 inhibition modulates pyroptosis to improve recovery after spinal cord injury

Excessive neuroinflammation and neuronal loss contribute to mechanisms of spinal cord injury (SCI). Accumulating evidence has suggested that topoisomerase 1 (Top1) inhibition can suppress exacerbated immune responses and protect against lethal inflammation. Pyroptosis is a recently identified pro-inflammatory programmed mode of cell death. However, the effects and underlying mechanisms of Top1 inhibition in SCI remains unclear. Locomotor functional recovery in mice was evaluated through Basso Mouse Scale (BMS). Neuronal loss was evaluated by immunochemistry staining of NeuN. Pyroptosis was determined by immunofluorescence staining, western blot, flow cytometry, cell viability, and cytotoxicity assays. In the present study, we estimated the effects of chemical inhibition of Top1 in an SCI model. Administration of Top1 inhibitor camptothecin (CPT) to mice significantly improved locomotor functional recovery after SCI. Moreover, CPT reduced Top1 level, inhibited nucleotide-binding oligomerization domain-like receptor 3 (NLRP3) inflammasome activation and pyroptosis, attenuated proinflammatory cytokines levels, diminished the number of neutrophil and neuronal loss in mice. Furthermore, CPT in oxygen-glucose deprivation neurons down-regulated Top1 level, attenuated NLRP3 inflammasome activation, and suppressed pyroptosis and inflammatory response. Together, our findings indicate that inhibition of Top1 with CPT can inhibit pyroptosis, control neuroinflammation, and improve functional recovery after SCI.