The SDF1-CXCR4 Axis Is Involved in the Hyperbaric Oxygen Therapy-Mediated Neuronal Cells Migration in Transient Brain Ischemic Rats

Expression of BDNF in the Cortex and Hippocampus of Mice With Middle Cerebral Artery Occlusion

BACKGROUND/AIM

Stroke is a cerebrovascular disease with high mortality and disability, causing motor dysfunction and cognitive impairments. Middle cerebral artery occlusion (MCAO) mouse models of ischemic stroke are used for identifying therapeutic targets. Ischemic insults to the brain alter brain-derived neurotrophic factor (BDNF) expression in cortical and hippocampal neurons. In the present study, we investigated BDNF expression in the cortex and hippocampus of mice following MCAO.

MATERIALS AND METHODS

Monofilament sutures coated with silicone rubber were introduced into the common carotid artery and occluded middle cerebral artery. The filament was withdrawn for reperfusion after 0.5 h. BDNF protein expression was measured using western blot. Immunofluorescence was performed with anti-NeuN and anti-BDNF antibodies.

RESULTS

BDNF expression in the cerebral cortex and hippocampus was decreased one and three days after MCAO, compared to the control group (unoperated mice). BDNF was expressed in NeuN-positive neurons in the dentate gyrus of the hippocampus and motor cortex of the MCAO and control groups.

CONCLUSION

MCAO in mice reduced the expression of BDNF in mature neurons of both the motor cortex and hippocampus at one and three days after surgery.

Combined Analysis of Human and Experimental Rat Samples Identified Biomarkers for Ischemic Stroke

The genetic transcription profile and underlying molecular mechanisms of ischemic stroke (IS) remain elusive. To address this issue, four mRNA and one miRNA expression profile of rats with middle cerebral artery occlusion (MCAO) were acquired from the Gene Expression Omnibus (GEO) database. A total of 780 differentially expressed genes (DEGs) and 56 miRNAs (DEMs) were screened. Gene set and functional enrichment analysis revealed that a substantial number of immune-inflammation-related pathways were abnormally activated in IS. Through weighted gene co-expression network analysis, the turquoise module was identified as meaningful. By taking the intersection of the turquoise module genes, DEM-target genes, and all DEGs, 354 genes were subsequently obtained as key IS-related genes. Among them, six characteristic genes were identified using the least absolute shrinkage and selection operator. After validation with three external datasets, transforming growth factor beta 1 (Tgfb1) was selected as the hub gene. This finding was further confirmed by gene expression pattern analysis in both the MCAO model rats and clinical IS patients. Moreover, the expression of the hub genes exhibited a negative correlation with the modified Rankin scale score (P < 0.05). Collectively, these results expand our knowledge of the genetic profile and molecular mechanisms involved in IS and suggest that the Tgfb1 gene is a potential biomarker of this disease.

Chemokines play a role in nerve damage and neuroprotection in vascular dementia

Various Chemotactic Factors (FCs) play different roles in neuronal injury in vascular dementia. CXCL5 and CCL11 exacerbate neurological injury by promoting inflammatory responses. CXCL12/SDF-1 and CX3CL1 play neuroprotective roles.CXCL13, XCL-1 and CCL2/ MCP-1 exacerbate neurological injury in the early stage, while exerting neuronal regeneration and neuroprotective effects in the chronic progressive phase. Chemokines often play an important role in the course of vascular dementia by regulating inflammatory responses, oxidative stress, and autophagy. Activation of microglia plays an important role in the regression of vascular dementia. Activated microglia M1 causes neuronal damage through the release of chemokines. And microglia M2 has anti-inflammatory effects and is involved in the repair of brain damage. Therefore, dynamic monitoring of various related FCs and understanding the relationship between FCs and microglia can help to understand and regulate the disease course progression of vascular dementia.At present, many scholars have confirmed in basic research that different subgroups of chemokines are closely related to vascular dementia. In clinical research, new immunotherapy methods that upregulate XCL-1 and drugs that regulate the activity of CCL2/CCR2 signaling pathways are being studied and promoted.

Hyperbaric oxygen therapy as a neuromodulatory technique: a review of the recent evidence

Hyperbaric oxygen therapy (HBOT) has recently emerged as a promising neuromodulatory modality for treating several neurological and psychological disorders. Various studies indicate that HBOT can promote brain recovery and neuroplasticity through the modulation of key cellular and molecular mechanisms. HBOT affects multiple primary pathways and cellular functions including mitochondrial biogenesis and function (increased Bcl-2, reduced Bax, and enhanced ATP production), neurogenesis (upregulation of Wnt-3 and VEGF/ERK signaling), synaptogenesis (elevated GAP43 and synaptophysin expression), and anti-inflammatory responses (reduced TNF-α and IL-6). These mechanisms contribute to significant clinical benefits, such as enhanced cognitive function, improved recovery from traumatic brain injury and post-concussion syndrome, and symptom reduction in conditions like post-traumatic stress disorder and fibromyalgia. By influencing these molecular targets, HBOT offers a novel approach to neuromodulation that warrants further exploration. This review discusses the representative mechanisms of action of HBOT and highlights its therapeutic neuromodulatory effects and potential clinical applications across various neurological and psychiatric conditions.

Research Advances in Neuroblast Migration in Traumatic Brain Injury

Neuroblasts were first derived from the adult mammalian brains in the 1990s by Reynolds et al. Since then, persistent neurogenesis in the subgranular zone (SGZ) of the hippocampus and subventricular zone (SVZ) has gradually been recognized. To date, reviews on neuroblast migration have largely investigated glial cells and molecular signaling mechanisms, while the relationship between vasculature and cell migration remains a mystery. Thus, this paper underlines the partial biological features of neuroblast migration and unravels the significance and mechanisms of the vasculature in the process to further clarify theoretically the neural repair mechanism after brain injury. Neuroblast migration presents three modes according to the characteristics of cells that act as scaffolds during the migration process: gliophilic migration, neurophilic migration, and vasophilic migration. Many signaling molecules, including brain-derived neurotrophic factor (BDNF), stromal cell-derived factor 1 (SDF-1), vascular endothelial growth factor (VEGF), and angiopoietin-1 (Ang-1), affect vasophilic migration, synergistically regulating the migration of neuroblasts to target areas along blood vessels. However, the precise role of blood vessels in the migration of neuroblasts needs to be further explored. The in-depth study of neuroblast migration will most probably provide theoretical basis and breakthrough for the clinical treatment of brain injury diseases.

Reactive Oxygen Species (ROS)-Mediated Antibacterial Oxidative Therapies: Available Methods to Generate ROS and a Novel Option Proposal

The increasing emergence of multidrug-resistant (MDR) pathogens causes difficult-to-treat infections with long-term hospitalizations and a high incidence of death, thus representing a global public health problem. To manage MDR bacteria bugs, new antimicrobial strategies are necessary, and their introduction in practice is a daily challenge for scientists in the field. An extensively studied approach to treating MDR infections consists of inducing high levels of reactive oxygen species (ROS) by several methods. Although further clinical investigations are mandatory on the possible toxic effects of ROS on mammalian cells, clinical evaluations are extremely promising, and their topical use to treat infected wounds and ulcers, also in presence of biofilm, is already clinically approved. Biochar (BC) is a carbonaceous material obtained by pyrolysis of different vegetable and animal biomass feedstocks at 200-1000 °C in the limited presence of O2. Recently, it has been demonstrated that BC's capability of removing organic and inorganic xenobiotics is mainly due to the presence of persistent free radicals (PFRs), which can activate oxygen, H2O2, or persulfate in the presence or absence of transition metals by electron transfer, thus generating ROS, which in turn degrade pollutants by advanced oxidation processes (AOPs). In this context, the antibacterial effects of BC-containing PFRs have been demonstrated by some authors against Escherichia coli and Staphylococcus aureus, thus giving birth to our idea of the possible use of BC-derived PFRs as a novel method capable of inducing ROS generation for antimicrobial oxidative therapy. Here, the general aspects concerning ROS physiological and pathological production and regulation and the mechanism by which they could exert antimicrobial effects have been reviewed. The methods currently adopted to induce ROS production for antimicrobial oxidative therapy have been discussed. Finally, for the first time, BC-related PFRs have been proposed as a new source of ROS for antimicrobial therapy via AOPs.

Hyperbaric Oxygen Therapy Attenuated the Motor Coordination and Cognitive Impairment of Polyglutamine Spinocerebellar Ataxia SCA17 Mice

Spinocerebellar ataxias (SCAs) are a large and diverse group of autosomal-dominant neurodegenerative diseases. No drugs have been approved for these relentlessly progressive and fatal SCAs. Our previous studies indicate that oxidative stress, neuroinflammation, and neuronal apoptosis are elevated in the SCA17 mice, which are the main therapeutic targets of hyperbaric oxygen treatment (HBOT). HBOT is considered to be an alternative and less invasive therapy for SCAs. In this study, we evaluated the HBOT (2.2 ATA for 14 days) effect and the persistence for the management of SCA17 mice and their wild-type littermates. We found HBOT attenuated the motor coordination and cognitive impairment of SCA17 mice and which persisted for about 1 month after the treatment. The results of several biochemistry and liver/kidney hematoxylin and eosin staining show the HBOT condition has no obvious toxicity in the mice. Immunostaining analyses show that the neuroprotective effect of HBOT could be through the promotion of BDNF production and the amelioration of neuroinflammation. Surprisingly, HBOT executes different effects on the male and female SCA17 mice, including the reduction of neuroinflammation and activation of CaMKII and ERK. This study suggests HBOT is a potential alternative therapeutic treatment for SCA17. Accumulated findings have revealed the similarity in disease pathomechanisms and possible therapeutic strategies in polyQ diseases; therefore, HBOT could be an optional treatment as well as the other polyQ diseases.

Targeting Neurogenesis in Seeking Novel Treatments for Ischemic Stroke

The interruption of cerebral blood flow leads to ischemic cell death and results in ischemic stroke. Although ischemic stroke is one of the most important causes of long-term disability and mortality, limited treatments are available for functional recovery. Therefore, extensive research has been conducted to identify novel treatments. Neurogenesis is regarded as a fundamental mechanism of neural plasticity. Therefore, therapeutic strategies targeting neurogenesis are thought to be promising. Basic research has found that therapeutic intervention including cell therapy, rehabilitation, and pharmacotherapy increased neurogenesis and was accompanied by functional recovery after ischemic stroke. In this review, we consolidated the current knowledge of the relationship between neurogenesis and treatment for ischemic stroke. It revealed that many treatments for ischemic stroke, including clinical and preclinical ones, have enhanced brain repair and functional recovery post-stroke along with neurogenesis. However, the intricate mechanisms of neurogenesis and its impact on stroke recovery remain areas of extensive research, with numerous factors and pathways involved. Understanding neurogenesis will lead to more effective stroke treatments, benefiting not only stroke patients but also those with other neurological disorders. Further research is essential to bridge the gap between preclinical discoveries and clinical implementation.

Nicorandil Exerts Anticonvulsant Effects in Pentylenetetrazol-Induced Seizures and Maximal-Electroshock-Induced Seizures by Downregulating Excitability in Hippocampal Pyramidal Neurons

N-(2-hydroxyethyl) nicotinamide nitrate (nicorandil), a nitrate that activates adenosine triphosphate (ATP)-sensitive potassium (K_ATP) channels, is generally used in the treatment of angina and offers long-term cardioprotective effects. It has been reported that several K_ATP channel openers can effectively alleviate the symptoms of seizure. The purpose of this study was to investigate the improvement in seizures induced by nicorandil. In this study, seizure tests were used to evaluate the effect of different doses of nicorandil by analysing seizure incidence, including minimal clonic seizure and generalised tonic-clonic seizure. We used a maximal electroshock seizure (MES) model, a metrazol maximal seizure (MMS) model and a chronic pentylenetetrazol (PTZ)-induced seizure model to evaluate the effect of nicorandil in improving seizures. Each mouse in the MES model was given an electric shock, while those in the nicorandil group received 0.5, 1, 2, 3 and 6 mg/kg of nicorandil by intraperitoneal injection, respectively. In the MMS model, the mice in the PTZ group and the nicorandil group were injected subcutaneously with PTZ (90 mg/kg), and the mice in the nicorandil group were injected intraperitoneally with 1, 3 and 5 mg/kg nicorandil, respectively. In the chronic PTZ-induced seizure model, the mice in the PTZ group and the nicorandil group were injected intraperitoneally with PTZ (40 mg/kg), and the mice in the nicorandil group were each given 1 and 3 mg/kg of PTZ at a volume of 200 nL. Brain slices containing the hippocampus were prepared, and cell-attached recording was used to record the spontaneous firing of pyramidal neurons in the hippocampal CA1 region. Nicorandil (i.p.) significantly increased both the maximum electroconvulsive protection rate in the MES model and the seizure latency in the MMS model. Nicorandil infused directly onto the hippocampal CA1 region via an implanted cannula relieved symptoms in chronic PTZ-induced seizures. The excitability of pyramidal neurons in the hippocampal CA1 region of the mice was significantly increased after both the acute and chronic administration of PTZ. To a certain extent, nicorandil reversed the increase in both firing frequency and proportion of burst spikes caused by PTZ (P < 0.05). Our results suggest that nicorandil functions by downregulating the excitability of pyramidal neurons in the hippocampal CA1 region of mice and is a potential candidate for the treatment of seizures.

The Role of Hyperbaric Oxygen Therapy in the Treatment of Surgical Site Infections: A Narrative Review

Surgical site infections (SSIs) are among the most prevalent postoperative complications, with significant morbidity and mortality worldwide. In the past half century, hyperbaric oxygen therapy (HBOT), the administration of 100% oxygen intermittently under a certain pressure, has been used as either a primary or alternative therapy for the management or treatment of chronic wounds and infections. This narrative review aims to gather information and evidence supporting the role of HBOT in the treatment of SSIs. We followed the Scale for the Quality Assessment of Narrative Review Articles (SANRA) guidelines and scrutinized the most relevant studies identified in Medline (via PubMed), Scopus, and Web of Science. Our review indicated that HBOT can result in rapid healing and epithelialization of various wounds and has potential beneficial effects in the treatment of SSIs or other similar infections following cardiac, neuromuscular scoliosis, coronary artery bypass, and urogenital surgeries. Moreover, it was a safe therapeutic procedure in most cases. The mechanisms related to the antimicrobial activity of HBOT include direct bactericidal effects through the formation of reactive oxygen species (ROS), the immunomodulatory effect of HBOT that increase the antimicrobial effects of the immune system, and the synergistic effects of HBOT with antibiotics. We emphasized the essential need for further studies, especially randomized clinical trials and longitudinal studies, to better standardize HBOT procedures as well as to determine its full benefits and possible side effects.

Functional Heterodimerization between the G Protein-Coupled Receptor GPR17 and the Chemokine Receptors 2 and 4: New Evidence

GPR17, a G protein-coupled receptor, is a pivotal regulator of myelination. Its endogenous ligands trigger receptor desensitization and downregulation allowing oligodendrocyte terminal maturation. In addition to its endogenous agonists, GPR17 could be promiscuously activated by pro-inflammatory oxysterols and chemokines released at demyelinating lesions. Herein, the chemokine receptors CXCR2 and CXCR4 were selected to perform both in silico modelling and in vitro experiments to establish their structural and functional interactions with GPR17. The relative propensity of GPR17 and CXCR2 or CXCR4 to form homo- and hetero-dimers was assessed by homology modelling and molecular dynamics (MD) simulations, and co-immunoprecipitation and immunoenzymatic assay. The interaction between chemokine receptors and GPR17 was investigated by determining receptor-mediated modulation of intracellular cyclic adenosine monophosphate (cAMP). Our data show the GPR17 association with CXCR2 or CXCR4 and the negative regulation of these interactions by CXCR agonists or antagonists. Moreover, GPR17 and CXCR2 heterodimers can functionally influence each other. In contrast, CXCR4 can influence GPR17 functionality, but not vice versa. According to MD simulations, all the dimers reached conformational stability and negative formation energy, confirming the experimental observations. The cross-talk between these receptors could play a role in the development of the neuroinflammatory milieu associated with demyelinating events.