Neuroprotective effects of neurotropin in a mouse model of hypoxic-ischemic brain injury

Lepalvir: Biomaterial efficacy and safety for patients with acute ischemic stroke

Lepalvir, derived from inflamed rabbit skin inoculated with vaccinia virus, has potential neuroprotective and anti-inflammatory effects. We conducted a phase II, multicenter, randomized, blind, placebo-controlled trial investigating the efficacy and safety of Lepalvir for acute ischemic stroke (AIS). Participants aged 18-80 years with AIS in the anterior circulation and a National Institutes of Health Stroke Scale (NIHSS) score of 4-24 within 48 h post-onset were randomized to receive high-dose (192U), low-dose (96U) Lepalvir, or saline placebo for 14 days. The primary outcome was the proportion of patients achieving a modified Rankin Scale (mRS) score ≤ 1 at day 90 (D90) post-randomization. Among 238 patients, no significant difference in mRS score at D90 was observed across groups, yet a higher percentage in the high-dose group achieved a mRS score ≤ 1 at D90, compared to the control and low-dose group. No significant safety concerns were noted. While functional improvement was not significantly different at D90, Lepalvir showed a favorable safety profile and potential at the higher dosage, warranting further phase III investigation.

Advances in genetically modified neural stem cell therapy for central nervous system injury and neurological diseases

Neural stem cells (NSCs) have increasingly been recognized as the most promising candidates for cell-based therapies for the central nervous system (CNS) injuries, primarily due to their pluripotent differentiation capabilities, as well as their remarkable secretory and homing properties. In recent years, extensive research efforts have been initiated to explore the therapeutic potential of NSC transplantation for CNS injuries, yielding significant advancements. Nevertheless, owing to the formation of adverse microenvironment at post-injury leading to suboptimal survival, differentiation, and integration within the host neural network of transplanted NSCs, NSC-based transplantation therapies often fall short of achieving optimal therapeutic outcomes. To address this challenge, genetic modification has been developed an attractive strategy to improve the outcomes of NSC therapies. This is mainly attributed to its potential to not only enhance the differentiation capacity of NSCs but also to boost a range of biological activities, such as the secretion of bioactive factors, anti-inflammatory effects, anti-apoptotic properties, immunomodulation, antioxidative functions, and angiogenesis. Furthermore, genetic modification empowers NSCs to play a more robust neuroprotective role in the context of nerve injury. In this review, we will provide an overview of recent advances in the roles and mechanisms of NSCs genetically modified with various therapeutic genes in the treatment of neural injuries and neural disorders. Also, an update on current technical parameters suitable for NSC transplantation and functional recovery in clinical studies are summarized.

Advances in nanomedicines: a promising therapeutic strategy for ischemic cerebral stroke treatment

Ischemic stroke, prevalent among the elderly, necessitates attention to reperfusion injury post treatment. Limited drug access to the brain, owing to the blood-brain barrier, restricts clinical applications. Identifying efficient drug carriers capable of penetrating this barrier is crucial. Blood-brain barrier transporters play a vital role in nutrient transport to the brain. Recently, nanoparticles emerged as drug carriers, enhancing drug permeability via surface-modified ligands. This article introduces the blood-brain barrier structure, elucidates reperfusion injury pathogenesis, compiles ischemic stroke treatment drugs, explores nanomaterials for drug encapsulation and emphasizes their advantages over conventional drugs. Utilizing nanoparticles as drug-delivery systems offers targeting and efficiency benefits absent in traditional drugs. The prospects for nanomedicine in stroke treatment are promising.

Neurotropin alleviates cognitive impairment by inhibiting TLR4/MyD88/NF-κB inflammation signaling pathway in mice with vascular dementia

Vascular dementia (VD) is the second most common cause of dementia after Alzheimer's disease. Neuroinflammation contributes to pathogenesis of VD. Neurotropin (NTP) is an analgesic that has been shown to suppress inflammation and neural repair. But its effects on VD are still unclear. Therefore, this study aimed to investigate the therapeutic effects and potential mechanisms of NTP in the VD model mice established by bilateral common carotid artery stenosis method. In VD mice, we found that NTP treatment increased cerebral blood flow by Laser speckle imaging, reduced neuron loss by Nissl, HE and immunochemistry staining, attenuated white matter damage by magnetic resonance imaging and ultrastructural damage by transmission electron microscope, improved cognitive functions by new object recognition test and three-chamber test, Y maze test and Morris water maze test, inhibited significantly glial activation by immunofluorescence methods, reduced the expression of TLR4, down-regulated expression of MyD88 and phosphorylation of NF-κB P65, decreased the levels of pro-inflammatory cytokines IL-1β, IL-6 and TNFα. Further, we showed that administration of a TLR4 inhibitor TAK242 had a similar effect to NTP, while the TLR4 agonist CRX-527 attenuated the effect of NTP in the VD mice. Collectively, our study suggested that NTP alleviates cognitive impairment by inhibiting TLR4/MyD88/NF-κB inflammation signaling pathway in the VD mice. Thus, NTP may be a promising therapeutic approach and a potential TLR4 inhibitor for VD.

Post-Event Application of Neurotropin Protects against Ischemic Insult toward Better Outcomes in a Murine Model of Subarachnoid Hemorrhage

Early brain injury (EBI) is closely linked to the development of delayed cerebral ischemia and poor outcomes after aneurysmal subarachnoid hemorrhage (SAH). This study aimed to evaluate the neuroprotective effect of neurotropin on EBI in a murine model of SAH. Twenty-four C57BL/6N mice were treated with intraperitoneal injections of either saline or 2.4 units of neurotropin at 1 h after SAH induction and for 3 days consecutively. SAH was created by an endovascular perforation method. In addition to the assessment of cerebral infarction and survival rate, motor and neurocognitive functions were also measured after SAH. Compared to the saline control group, the neurotropin group showed better recovery from locomotive and neurological declines after SAH. The neurotropin group also showed lower rates of post-SAH acute cerebral infarction and better memory and route-learning scores (p < 0.05). Meanwhile, there was no significant between-group differences in the overall mortality, hemodynamic parameters, or body weights. In conclusion, post-event treatment with neurotropin could be protective against EBI, lowering the incidence of ischemia and improving some motor and neurocognitive functions after SAH.

Effects of Melatonin on Neurobehavior and Cognition in a Cerebral Palsy Model of plppr5-/- Mice

Cerebral palsy (CP), a group of clinical syndromes caused by non-progressive brain damage in the developing fetus or infant, is one of the most common causes of lifelong physical disability in children in most countries. At present, many researchers believe that perinatal cerebral hypoxic ischemic injury or inflammatory injury are the main causes of cerebral palsy. Previous studies including our works confirmed that melatonin has a protective effect against convulsive brain damage during development and that it affects the expression of various molecules involved in processes such as metabolism, plasticity and signaling in the brain. Integral membrane protein plppr5 is a new member of the plasticity-related protein family, which is specifically expressed in brain and spinal cord, and induces filopodia formation as well as neurite growth. It is highly expressed in the brain, especially in areas of high plasticity, such as the hippocampus. The signals are slightly lower in the cortex, the cerebellum, and in striatum. Noteworthy, during development plppr5 mRNA is expressed in the spinal cord, i.e., in neuron rich regions such as in medial motor nuclei, suggesting that plppr5 plays an important role in the regulation of neurons. However, the existing literature only states that plppr5 is involved in the occurrence and stability of dendritic spines, and research on its possible involvement in neonatal ischemic hypoxic encephalopathy has not been previously reported. We used plppr5 knockout (plppr5-/-) mice and their wild-type littermates to establish a model of hypoxicischemic brain injury (HI) to further explore the effects of melatonin on brain injury and the role of plppr5 in this treatment in an HI model, which mainly focuses on cognition, exercise, learning, and memory. All the tests were performed at 3-4 weeks after HI. As for melatonin treatment, which was performed 5 min after HI injury and followed by every 24h. In these experiments, we found that there was a significant interaction between genotype and treatment in novel object recognition tests, surface righting reflex tests and forelimb suspension reflex tests, which represent learning and memory, motor function and coordination, and the forelimb grip of the mice, respectively. However, a significant main effect of genotype and treatment on performance in all behavioral tests were observed. Specifically, wild-type mice with HI injury performed better than plppr5-/- mice, regardless of treatment with melatonin or vehicle. Moreover, treatment with melatonin could improve behavior in the tests for wild-type mice with HI injury, but not for plppr5-/- mice. This study showed that plppr5 knockout aggravated HI damage and partially weakened the neuroprotection of melatonin in some aspects (such as novel object recognition test and partial nerve reflexes), which deserves further study.

Neuroprotection by Neurotropin through Crosstalk of Neurotrophic and Innate Immune Receptors in PC12 Cells

Infected or damaged tissues release multiple “alert” molecules such as alarmins and damage-associated molecular patterns (DAMPs) that are recognized by innate immune receptors, and induce tissue inflammation, regeneration, and repair. Recently, an extract from inflamed rabbit skin inoculated with vaccinia virus (Neurotropin^®, NTP) was found to induce infarct tolerance in mice receiving permanent ischemic attack to the middle cerebral artery. Likewise, we report herein that NTP prevented the neurite retraction in PC12 cells by nerve growth factor (NGF) deprivation. This effect was accompanied by interaction of Fyn with high-affinity NGF receptor TrkA. Sucrose density gradient subcellular fractionation of NTP-treated cells showed heretofore unidentified membrane fractions with a high-buoyant density containing Trk, B subunit of cholera toxin-bound ganglioside, flotillin-1 and Fyn. Additionally, these new membrane fractions also contained Toll-like receptor 4 (TLR4). Inhibition of TLR4 function by TAK-242 prevented the formation of these unidentified membrane fractions and suppressed neuroprotection by NTP. These observations indicate that NTP controls TrkA-mediated signaling through the formation of clusters of new membrane microdomains, thus providing a platform for crosstalk between neurotrophic and innate immune receptors. Neuroprotective mechanisms through the interaction with innate immune systems may provide novel mechanism for neuroprotection.

Schisandrin B improves cerebral ischemia and reduces reperfusion injury in rats through TLR4/NF-κB signaling pathway inhibition

It has been established that poor outcomes in ischemic stroke patients are associated with the post-reperfusion inflammatory response and up-regulation of TLR4. Therefore, suppression of the TLR4 signaling pathway constitutes a potential neuroprotective therapeutic strategy. Schisandrin B, a compound extracted from Schisandra chinensis, has been shown to possess anti-inflammatory and neuroprotective properties. However, the mechanism remains unclear. In the present study, the therapeutic effect of schisandrin B was assessed following cerebral ischemia and reperfusion (I/R) injury in a model of middle cerebral artery occlusion and reperfusion (MCAO/R) in rats. The effects of schisandrin B were investigated with particular emphasis on TLR4 signal transduction and on the inflammatory response. Schisandrin B treatment conferred significant protection against MCAO/R injury, as evidenced by decreases in infarct volume, neurological score, and the number of apoptotic neurons and inflammatory signaling molecules.

ABBREVIATIONS

I/R: schemia/reperfusion; IL: interleukin; MCAO/R: middle cerebral artery occlusion and reperfusion; NF-κB: nuclear; TLR4: Toll-like receptor 4; TNF-α: tumor necrosis factor-α.

Neurotropin exerts neuroprotective effects after spinal cord injury by inhibiting apoptosis and modulating cytokines

Background/objective

Spinal cord injury (SCI) severely and irreversibly damages the central nervous system. Neurotropin (NTP), a nonprotein extract obtained from inflamed rabbit skin inoculated with vaccinia virus, is a drug that has been used for more than sixty years to alleviate neuropathic pain. It also reportedly exerts a neuroprotective role in peripheral nerves and in response to various central nervous system diseases, such as brain injury and Alzheimer disease. However, whether NTP promotes SCI recovery remains unknown. This study evaluated NTP's effects after SCI and explored its underlying mechanisms in a rat contusion model of SCI.

Method

NTP was intraperitoneally administered to adult female Wistar rats subjected to contusion-induced SCI. Functional recovery was evaluated with behavioural scores and electrophysiological examinations. Tissue recovery was assessed with magnetic resonance imaging as well as histological staining with haematoxylin and eosin and Luxol Fast Blue. Neuronal survival and gliosis were observed after NeuN and glial fibrillary acidic protein immunofluorescence. Levels of apoptosis were demonstrated with TdT-mediated dUTP nick-end labeling (TUNEL) staining, Caspase-3 and B-cell lymphoma-2 (Bcl-2) Western blot, and Annexin V/propidium iodide flow cytometry. A protein antibody chip analysis was performed to evaluate the expression levels of 67 rat cytokines.

Results

NTP treatment improved the hindlimb locomotor recovery of the injured animals as well as their electrophysiological outcomes after SCI. A dosage of 50 NTP units/kg was found to optimize the efficacy of NTP. Magnetic resonance imaging revealed that lesion sizes decreased after NTP treatment. The haematoxylin and eosin and Luxol Fast Blue staining showed significant increases in the amount of spared tissue. The NeuN and glial fibrillary acidic protein immunofluorescence revealed that NTP treatment increased neuronal survival and reduced gliosis in tissue samples obtained from the lesion's epicentre. That NTP inhibited apoptosis was confirmed by the decreased number of TUNEL-positive cells, level of Caspase-3 expression, and number of Annexin V/propidium iodide–positive cells, as well as the increased level of Bcl-2 expression. The protein array analysis identified 28 differentially expressed proteins in the NTP group, and the gene ontology (GO) analysis showed that the enriched differentially expressed proteins implicate janus kinase-signal transducer and activator of transcription (JAK-STAT) signalling pathways. The expression levels of proinflammatory cytokines such as interleukin 6, thymus chemokine-1(TCK-1), and lipopolysaccharide-induced CXC chemokine (LIX) decreased after NTP treatment, whereas the levels of prorepair cytokine hepatocyte growth factor and adiponectin increased.

Conclusion

Our research provides evidence that NTP can improve functional outcomes and alleviate secondary injury after SCI by inhibiting apoptosis and modulating cytokines.

The translational potential of this article

The multicomponent NTP might have broad target spectra in SCI pathophysiology and halt the secondary injury cascade. As a safe drug that features sixty years of clinical use as an analgesic, translating this demonstrated efficacy of NTP to addressing SCI in human patients may potentially be accelerated.