The Role of Nanomaterials in Stroke Treatment: Targeting Oxidative Stress

Nanomaterial-Based Strategies for Attenuating T-Cell-Mediated Immunodepression in Stroke Patients: Advancing Research Perspectives

This review article discusses the potential of nanomaterials in targeted therapy and immunomodulation for stroke-induced immunosuppression. Although nanomaterials have been extensively studied in various biomedical applications, their specific use in studying and addressing immunosuppression after stroke remains limited. Stroke-induced neuroinflammation is characterized by T-cell-mediated immunodepression, which leads to increased morbidity and mortality. Key observations related to immunodepression after stroke, including lymphopenia, T-cell dysfunction, regulatory T-cell imbalance, and cytokine dysregulation, are discussed. Nanomaterials, such as liposomes, micelles, polymeric nanoparticles, and dendrimers, offer advantages in the precise delivery of drugs to T cells, enabling enhanced targeting and controlled release of immunomodulatory agents. These nanomaterials have the potential to modulate T-cell function, promote neuroregeneration, and restore immune responses, providing new avenues for stroke treatment. However, challenges related to biocompatibility, stability, scalability, and clinical translation need to be addressed. Future research efforts should focus on comprehensive studies to validate the efficacy and safety of nanomaterial-based interventions targeting T cells in stroke-induced immunosuppression. Collaborative interdisciplinary approaches are necessary to advance the field and translate these innovative strategies into clinical practice, ultimately improving stroke outcomes and patient care.

Classification and application of metal-based nanoantioxidants in medicine and healthcare

Antioxidants play an important role in the prevention of oxidative stress and have been widely used in medicine and healthcare. However, natural antioxidants have several limitations such as low stability, difficult long-term storage, and high cost of large-scale production. Along with significant advances in nanotechnology, nanomaterials have emerged as a promising solution to improve the limitations of natural antioxidants because of their high stability, easy storage, time effectiveness, and low cost. Among various types of nanomaterials exhibiting antioxidant activity, metal-based nanoantioxidants show excellent reactivity because of the presence of an unpaired electron in their atomic structure. In this review, we summarize some novel metal-based nanoantioxidants and classify them into two main categories, namely chain-breaking and preventive antioxidant nanomaterials. In addition, the applications of antioxidant nanomaterials in medicine and healthcare are also discussed. This review provides a deeper understanding of the mechanisms of metal-based nanoantioxidants and a guideline for using these nanomaterials in medicine and healthcare.

Gold Nanoparticles in Neurological Diseases: A Review of Neuroprotection

This review explores the diverse applications of gold nanoparticles (AuNPs) in neurological diseases, with a specific focus on Alzheimer's disease (AD), Parkinson's disease (PD), and stroke. The introduction highlights the pivotal role of neuroinflammation in these disorders and introduces the unique properties of AuNPs. The review's core examines the mechanisms by which AuNPs exert neuroprotection and anti-neuro-inflammatory effects, elucidating various pathways through which they manifest these properties. The potential therapeutic applications of AuNPs in AD are discussed, shedding light on promising avenues for therapy. This review also explores the prospects of utilizing AuNPs in PD interventions, presenting a hopeful outlook for future treatments. Additionally, the review delves into the potential of AuNPs in providing neuroprotection after strokes, emphasizing their significance in mitigating cerebrovascular accidents' aftermath. Experimental findings from cellular and animal models are consolidated to provide a comprehensive overview of AuNPs' effectiveness, offering insights into their impact at both the cellular and in vivo levels. This review enhances our understanding of AuNPs' applications in neurological diseases and lays the groundwork for innovative therapeutic strategies in neurology.

Selenium Nanoparticles in Protecting the Brain from Stroke: Possible Signaling and Metabolic Mechanisms

Strokes rank as the second most common cause of mortality and disability in the human population across the world. Currently, available methods of treating or preventing strokes have significant limitations, primarily the need to use high doses of drugs due to the presence of the blood-brain barrier. In the last decade, increasing attention has been paid to the capabilities of nanotechnology. However, the vast majority of research in this area is focused on the mechanisms of anticancer and antiviral effects of nanoparticles. In our opinion, not enough attention is paid to the neuroprotective mechanisms of nanomaterials. In this review, we attempted to summarize the key molecular mechanisms of brain cell damage during ischemia. We discussed the current literature regarding the use of various nanomaterials for the treatment of strokes. In this review, we examined the features of all known nanomaterials, the possibility of which are currently being studied for the treatment of strokes. In this regard, the positive and negative properties of nanomaterials for the treatment of strokes have been identified. Particular attention in the review was paid to nanoselenium since selenium is a vital microelement and is part of very important and little-studied proteins, e.g., selenoproteins and selenium-containing proteins. An analysis of modern studies of the cytoprotective effects of nanoselenium made it possible to establish the mechanisms of acute and chronic protective effects of selenium nanoparticles. In this review, we aimed to combine all the available information regarding the neuroprotective properties and mechanisms of action of nanoparticles in neurodegenerative processes, especially in cerebral ischemia.

Recent Advances in Chemically Engineered Nanostructures Impact on Ischemic Stroke Treatment

Stroke is a serious public health problem that raises expenses for society and causes long-term impairment and death. However, due to restricted blood-brain barrier (BBB) penetration, there are few treatment alternatives for treating stroke. Recanalization techniques, neuroprotective medications, and recovery techniques are all forms of treatment. The ischemic stroke treatment window is too narrow for logical and efficient therapy, and detection is possible only in advanced stages. BBB integrity disruption, neurotoxicity, and the brief half-life of therapeutic thrombolytics are the key molecular pathogenic causes of ischemic stroke. Existing neuroprotective drugs' inability to promote the recovery of ischemic brain tissue after a stroke is another factor that contributes to the disease's progression, chronic nature, and severity. A possible approach to getting around these medication restrictions and boosting the effectiveness of therapies is nanotechnology. In order to get around these drug-related restrictions and boost the effectiveness of therapies for neurological conditions such as stroke, nanotechnology has emerged as a viable option. These problems might be avoided by using nanoparticle-based methods to create a thrombolytic medication that is safe to use after the tissue plasminogen activator (tPA) treatment window has passed. The idea of using biomimetic nanoparticles in the future for the treatment of ischemic stroke through immunotherapy and stem cell therapy is highlighted, along with recent advancements in the study of nanomaterials for ischemic stroke diagnostics and treatment.

Nanoparticle Formulations of Antioxidants for the Management of Oxidative Stress in Stroke: A Review

Stroke is currently one of the primary causes of morbidity and mortality worldwide. Unfortunately, there has been a lack of effective stroke treatment. Therefore, novel treatment strategies are needed to decrease stroke-induced morbidity and promote the patient's quality of life. Reactive oxygen species (ROS) have been recognized as one of the major causes of brain injury after ischemic stroke. Antioxidant therapy seems to be an effective treatment in the management of oxidative stress relevant to inflammatory disorders like stroke. However, the in vivo efficacy of traditional anti-oxidative substances is greatly limited due to their non-specific distribution and poor localization in the disease region. In recent years, antioxidant nanoparticles (NPs) have demonstrated a clinical breakthrough for stroke treatment. Some NPs have intrinsic antioxidant properties and act as antioxidants to scavenge ROS. Moreover, NPs provide protection to the antioxidant agents/enzymes while effectively delivering them into unreachable areas like the brain. Because of their nanoscale dimensions, NPs are able to efficiently pass through the BBB, and easily reach the damaged site. Here, we discuss the challenges, recent advances, and perspectives of antioxidant NPs in stroke treatment.

Oxidative stress as a bridge between age and stroke: A narrative review

Stroke is the third most common cause of death globally and a leading cause of disability. The cellular and molecular changes following stroke and causes of neuronal death are not fully understood, and there are few effective treatments currently available. A rapid increase in the levels of reactive oxygen species (ROS) post stroke can overwhelm antioxidant defenses and trigger a series of pathophysiologic events including the inflammatory response, blood-brain barrier (BBB) disruption, apoptosis, and autophagy, ultimately leading to neuron degeneration and apoptosis. It is thought that beyond a certain age, the ROS accumulation resulting from stroke increases the risk of morbidity and mortality. In the present review, we summarize the role of oxidative stress (OS) as a link between aging and stroke pathogenesis. We also discuss how antioxidants can play a beneficial role in the prevention and treatment of stroke by eliminating harmful ROS, delaying aging, and alleviating damage to neurons.

Neuroinflammation in the Evolution of Motor Function in Stroke and Trauma Patients: Treatment and Potential Biomarkers

Neuroinflammation has a significant impact on different pathologies, such as stroke or spinal cord injury, intervening in their pathophysiology: expansion, progression, and resolution. Neuroinflammation involves oxidative stress, damage, and cell death, playing an important role in neuroplasticity and motor dysfunction by affecting the neuronal connection responsible for motor control. The diagnosis of this pathology is performed using neuroimaging techniques and molecular diagnostics based on identifying and measuring signaling molecules or specific markers. In parallel, new therapeutic targets are being investigated via the use of bionanomaterials and electrostimulation to modulate the neuroinflammatory response. These novel diagnostic and therapeutic strategies have the potential to facilitate the development of anticipatory patterns and deliver the most beneficial treatment to improve patients' quality of life and directly impact their motor skills. However, important challenges remain to be solved. Hence, the goal of this study was to review the implication of neuroinflammation in the evolution of motor function in stroke and trauma patients, with a particular focus on novel methods and potential biomarkers to aid clinicians in diagnosis, treatment, and therapy. A specific analysis of the strengths, weaknesses, threats, and opportunities was conducted, highlighting the key challenges to be faced in the coming years.

The effect of regulating MCU expression on experimental ischemic brain injury

Mitochondrial calcium uniporter (MCU) is a critical channel for Ca²⁺ influx into mitochondria. The present study aimed to determine if MCU knockdown has beneficial effects on ischemic brain injury and to explore the underlying mechanisms. The present study demonstrated that MCU knockdown but not total knockout (KO) attenuated ischemia infarction volume and primary cortical neuronal cells' ischemic damage. MCU knockdown maintained mitochondrial ultrastructure, alleviated calcium overload, and reduced mitochondrial apoptosis. Moreover, MCU knockdown regulated the changes of MICU1 and MICU2 after cerebral infarction, while no changes were observed in other mitochondrial calcium handling proteins. Based on metabolomics, MCU knockdown reversed middle cerebral artery occlusion (MCAO)-induced up-regulated phosphoenolpyruvate and down-regulated GDP to protect energy metabolism after cerebral infarction. Furthermore, a total of 87 and 245 differentially expressed genes (DEGs) were detected by transcriptome sequencing among WT mice, MCU KO mice and MCU knockdown mice in the MCAO model, respectively. Then, NR4A1 was identified as one of the DEGs in different MCU expressions in vivo ischemia stroke model via transcriptomic screening and genetic validation. Furthermore, MCU knockdown downregulated the ischemia-induced upregulation of NR4A1 expression. Together, this is the further evidence that the MCU knockdown exerts a protective role after cerebral infarction by promoting calcium homeostasis, inhibiting mitochondrial apoptosis and protecting energy metabolism.

Label-Free, Reusable, Equipment-Free, and Visual Detection of Hydrogen Sulfide Using a Colorimetric and Fluorescent Dual-Mode Sensing Platform

In this work, we have found for the first time that the fluorescence of rhodamine B (RhB) would be dramatically reduced after it bound to hemin/G-quadruplex and reacted with •OH. Based on this finding, we have designed a colorimetric and fluorescent dual-mode sensing platform for visual detection of hydrogen sulfide (H₂S). The constructed sensor is based on the formation of dsDNA and the G-quadruplex structure by the cytosine-Ag⁺-cytosine mismatch, causing H₂O₂-mediated catalysis to oxidize ABTS or RhB to induce a colorimetric or fluorescent change. In the presence of H₂S, the solution color for colorimetric and fluorescent assays would change from dark green to pink and from green (fluorescence off) to bright yellow (fluorescence on), respectively. This dual-mode assay showed high selectivity toward H₂S over other interference materials with a low measurable detection limit value (below than 2.5 μM), and it has been successfully applied to H₂S visual detection in real samples. Moreover, the dual-mode sensing strategy presented an excellent reutilization character both in colorimetric and fluorescent assays. This method was employed as a label-free, simple, fast, and equipment-free platform for H₂S detection with high selectivity and reusability. This work realized naked-eye detection both in colorimetric and fluorescent analysis at a lower concentration of H₂S, demonstrating a promising strategy for on-site visual detection of H₂S.

Antioxidants attenuate mitochondrial oxidative damage through the Nrf2 pathway: A promising therapeutic strategy for stroke

Stroke represents one of the leading causes of disability and death worldwide. Reactive oxygen species overproduction-induced oxidative stress in mitochondria results in mitochondrial DNA damage, mitochondrial autophagy (mitophagy), inflammation, and apoptosis during the pathologic progression of stroke. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator that induces the transcription of a wide range of antioxidant genes to attenuate mitochondrial oxidative stress. Different antioxidative compounds, including polyphenols, mitochondrial antioxidants, triterpenoids, and others, have been shown to be able to activate Nrf2 and, thus, exert neuroprotective effects on stroke by ameliorating mitochondrial oxidative damage. In this review, we briefly discussed the role of mitochondrial oxidative stress in the pathophysiology of stroke and focused on the protective effects of antioxidative compounds through attenuating mitochondrial oxidative damage by activating Nrf2 in stroke. In conclusion, these antioxidants may represent novel therapeutic strategies against stroke.

The progress of research on the application of redox nanomaterials in disease therapy

Redox imbalance can trigger cell dysfunction and damage and plays a vital role in the origin and progression of many diseases. Maintaining the balance between oxidants and antioxidants in vivo is a complicated and arduous task, leading to ongoing research into the construction of redox nanomaterials. Nanodrug platforms with redox characteristics can not only reduce the adverse effects of oxidative stress on tissues by removing excess oxidants from the body but also have multienzyme-like activity, which can play a cytotoxic role in tumor tissues through the catalytic oxidation of their substrates to produce harmful reactive oxygen species such as hydroxyl radicals. In this review, various redox nanomaterials currently used in disease therapy are discussed, emphasizing the treatment methods and their applications in tumors and other human tissues. Finally, the limitations of the current clinical application of redox nanomaterials are considered.

Perspective insights into hydrogels and nanomaterials for ischemic stroke

Ischemic stroke (IS) is a neurological disorder prevalent worldwide with a high disability and mortality rate. In the clinic setting, tissue plasminogen activator (tPA) and thrombectomy could restore blood flow of the occlusion region and improve the outcomes of IS patients; however, these therapies are restricted by a narrow time window. Although several preclinical trials have revealed the molecular and cellular mechanisms underlying infarct lesions, the translatability of most findings is unsatisfactory, which contributes to the emergence of new biomaterials, such as hydrogels and nanomaterials, for the treatment of IS. Biomaterials function as structural scaffolds or are combined with other compounds to release therapeutic drugs. Biomaterial-mediated drug delivery approaches could optimize the therapeutic effects based on their brain-targeting property, biocompatibility, and functionality. This review summarizes the advances in biomaterials in the last several years, aiming to discuss the therapeutic potential of new biomaterials from the bench to bedside. The promising prospects of new biomaterials indicate the possibility of an organic combination between materialogy and medicine, which is a novel field under exploration.

The hallmark and crosstalk of immune cells after intracerebral hemorrhage: Immunotherapy perspectives

Intracerebral hemorrhage (ICH) is one of the most dangerous types of strokes with a high morbidity and mortality rate. Currently, the treatment of ICH is not well developed, mainly because its mechanisms are still unclear. Inflammation is one of the main types of secondary injury after ICH and catalyzes the adverse consequences of ICH. A large number of immune cells are involved in neuroinflammation, such as microglia, astrocytes, oligodendrocytes, lymphocytes, macrophages, and neutrophils. Nevertheless, the characteristics and crosstalk of immune cells have not been fully elucidated. In this review, we endeavor to delve into the respective characteristics of immune cells and their interactions in neuroimmune inflammation, and further elucidate favorable immunotherapeutic approaches regarding ICH, and finally present an outlook.

Possible Synergies of Nanomaterial-Assisted Tissue Regeneration in Plasma Medicine: Mechanisms and Safety Concerns

Cold atmospheric plasma and nanomedicine originally emerged as individual domains, but are increasingly applied in combination with each other. Most research is performed in the context of cancer treatment, with only little focus yet on the possible synergies. Many questions remain on the potential of this promising hybrid technology, particularly regarding regenerative medicine and tissue engineering. In this perspective article, we therefore start from the fundamental mechanisms in the individual technologies, in order to envision possible synergies for wound healing and tissue recovery, as well as research strategies to discover and optimize them. Among these strategies, we demonstrate how cold plasmas and nanomaterials can enhance each other's strengths and overcome each other's limitations. The parallels with cancer research, biotechnology and plasma surface modification further serve as inspiration for the envisioned synergies in tissue regeneration. The discovery and optimization of synergies may also be realized based on a profound understanding of the underlying redox- and field-related biological processes. Finally, we emphasize the toxicity concerns in plasma and nanomedicine, which may be partly remediated by their combination, but also partly amplified. A widespread use of standardized protocols and materials is therefore strongly recommended, to ensure both a fast and safe clinical implementation.

Activation of LRP6 with HLY78 Attenuates Oxidative Stress and Neuronal Apoptosis via GSK3β/Sirt1/PGC-1α Pathway after ICH

Background

Oxidative stress and neuronal apoptosis have important roles in the pathogenesis after intracerebral hemorrhage (ICH). Previous studies have reported that low-density lipoprotein receptor-related protein 6 (LRP6) exerts neuroprotection in several neurological diseases. Herein, we investigate the role of LRP6 receptor activation with HLY78 to attenuate oxidative stress and neuronal apoptosis after ICH, as well as the underlying mechanism.

Methods

A total of 199 CD1 mice were used. ICH was induced via injection of autologous blood into the right basal ganglia. HLY78 was administered via intranasal injection at 1 h after ICH. To explore the underlying mechanism, LRP6 siRNA and selisistat, a Sirt1 selective antagonist, were injected intracerebroventricularly at 48 h before ICH induction. Neurobehavioral tests, Western blot, and immunofluorescence staining were performed.

Results

The expression of endogenous p-LRP6 was gradually increased and expressed on neurons after ICH. HLY78 significantly improved the short- and long-term neurobehavioral deficits after ICH, which was accompanied with decreased oxidative stress and neuronal apoptosis, as well as increased expression of p-GSK3β, Sirt1, and PGC-1α, as well as downregulation of Romo-1 and C-Caspase-3. LRP6 knockdown or Sirt1 inhibition abolished these effects of HLY78 after ICH.

Conclusion

Our results suggest that administration of HLY78 attenuated oxidative stress, neuronal apoptosis, and neurobehavioral impairments through the LRP6/GSK3β/Sirt1/PGC-1α signaling pathway after ICH.

Oxidative Stress in Ischemia/Reperfusion Injuries following Acute Ischemic Stroke

Recanalization therapy is increasingly used in the treatment of acute ischemic stroke. However, in about one third of these patients, recanalization is followed by ischemia/reperfusion injuries, and clinically to worsening of the neurological status. Much research has focused on unraveling the involved mechanisms in order to prevent or efficiently treat these injuries. What we know so far is that oxidative stress and mitochondrial dysfunction are significantly involved in the pathogenesis of ischemia/reperfusion injury. However, despite promising results obtained in experimental research, clinical studies trying to interfere with the oxidative pathways have mostly failed. The current article discusses the main mechanisms leading to ischemia/reperfusion injuries, such as mitochondrial dysfunction, excitotoxicity, and oxidative stress, and reviews the clinical trials with antioxidant molecules highlighting recent developments and future strategies.

From blood to brain: blood cell-based biomimetic drug delivery systems

Brain drug delivery remains a major difficulty for several challenges including the blood-brain barrier, lesion spot targeting, and stability during circulation. Blood cells including erythrocytes, platelets, and various subpopulations of leukocytes have distinct features such as long-circulation, natural targeting, and chemotaxis. The development of biomimetic drug delivery systems based on blood cells for brain drug delivery is growing fast by using living cells, membrane coating nanotechnology, or cell membrane-derived nanovesicles. Blood cell-based vehicles are superior delivery systems for their engineering feasibility and versatile delivery ability of chemicals, proteins, and all kinds of nanoparticles. Here, we focus on advances of blood cell-based biomimetic carriers for from blood to brain drug delivery and discuss their translational challenges in the future.

Oxidative Stress in the Brain: Basic Concepts and Treatment Strategies in Stroke

The production of free radicals is inevitably associated with metabolism and other enzymatic processes. Under physiological conditions, however, free radicals are effectively eliminated by numerous antioxidant mechanisms. Oxidative stress occurs due to an imbalance between the production and elimination of free radicals under pathological conditions. Oxidative stress is also associated with ageing. The brain is prone to oxidative damage because of its high metabolic activity and high vulnerability to ischemic damage. Oxidative stress, thus, plays a major role in the pathophysiology of both acute and chronic pathologies in the brain, such as stroke, traumatic brain injury or neurodegenerative diseases. The goal of this article is to summarize the basic concepts of oxidative stress and its significance in brain pathologies, as well as to discuss treatment strategies for dealing with oxidative stress in stroke.

Therapeutic Nanoparticles for the Different Phases of Ischemic Stroke

Stroke represents the second leading cause of mortality and morbidity worldwide. Ischemic strokes are the most prevalent type of stroke, and they are characterized by a series of pathological events prompted by an arterial occlusion that leads to a heterogeneous pathophysiological response through different hemodynamic phases, namely the hyperacute, acute, subacute, and chronic phases. Stroke treatment is highly reliant on recanalization therapies, which are limited to only a subset of patients due to their narrow therapeutic window; hence, there is a huge need for new stroke treatments. Nonetheless, the vast majority of promising treatments are not effective in the clinical setting due to their inability to cross the blood-brain barrier and reach the brain. In this context, nanotechnology-based approaches such as nanoparticle drug delivery emerge as the most promising option. In this review, we will discuss the current status of nanotechnology in the setting of stroke, focusing on the diverse available nanoparticle approaches targeted to the different pathological and physiological repair mechanisms involved in each of the stroke phases.

Salivary Biomarkers of Oxidative Stress and Inflammation in Stroke Patients: From Basic Research to Clinical Practice

Cerebral stroke is a serious worldwide health problem, as can be seen by the global epidemic of the disease. In this disorder, when the blood flow is compromised by ruptures or blocked arteries, sudden death of neurons is observed as a result of a lack of oxygen and nutrients. Numerous severe problems and frequent complications also exist in stroke patients; therefore, there is an urgent need to develop new therapeutic, diagnostic, and prognostic methods for the disease. At present, the diagnosis of stroke is based on a neurological examination, medical history, and neuroimaging, due to the fact that rapid and noninvasive diagnostic tests are unavailable. Nevertheless, oxidative stress and inflammation are considered key factors in stroke pathogenesis. Oxygen free radicals are responsible for oxidation of lipids, proteins, and DNA/RNA, which in turn contributes to oxidative damage of the brain. Toxic products of the oxidation reactions act cytostatically on the cell by damaging cell membranes and leading to neuronal death by apoptosis or necrosis. Thus, it seems that redox/inflammatory biomarkers might be used in the diagnosis of the disease. Nowadays, saliva is of increasing interest in clinical laboratory medicine. Redox biomarkers could be obtained easily, noninvasively, cheaply, and stress-free from saliva. This minireview is aimed at presenting the current knowledge concerning the use of salivary biomarkers of oxidative stress and inflammation in the diagnosis and prognosis of stroke.