Progresses and Prospects of Neuroprotective Agents-Loaded Nanoparticles and Biomimetic Material in Ischemic Stroke

The emerging role of nitric oxide in the synaptic dysfunction of vascular dementia

With an increase in global aging, the number of people affected by cerebrovascular diseases is also increasing, and the incidence of vascular dementia-closely related to cerebrovascular risk-is increasing at an epidemic rate. However, few therapeutic options exist that can markedly improve the cognitive impairment and prognosis of vascular dementia patients. Similarly in Alzheimer's disease and other neurological disorders, synaptic dysfunction is recognized as the main reason for cognitive decline. Nitric oxide is one of the ubiquitous gaseous cellular messengers involved in multiple physiological and pathological processes of the central nervous system. Recently, nitric oxide has been implicated in regulating synaptic plasticity and plays an important role in the pathogenesis of vascular dementia. This review introduces in detail the emerging role of nitric oxide in physiological and pathological states of vascular dementia and summarizes the diverse effects of nitric oxide on different aspects of synaptic dysfunction, neuroinflammation, oxidative stress, and blood-brain barrier dysfunction that underlie the progress of vascular dementia. Additionally, we propose that targeting the nitric oxide-sGC-cGMP pathway using certain specific approaches may provide a novel therapeutic strategy for vascular dementia.

A review: oligodendrocytes in neuronal axonal conduction and methods for enhancing their performance

OBJECTIVES

This review explores the vital role of oligodendrocytes in axon myelination and efficient neuronal transmission and the impact of dysfunction resulting from neurotransmitter deficiencies related disorders. Furthermore, the review also provides insight into the potential of bionanotechnology for addressing neurodegenerative diseases by targeting oligodendrocytes.

METHODS

A review of literature in the field was conducted using Google scholar. Systematic searches were performed to identify relevant studies and reviews addressing the role of oligodendrocytes in neural function, the influence of neurotransmitters on oligodendrocyte differentiation, and the potential of nanotechnology-based strategies for targeted therapy of oligodendrocytes.

RESULTS

This review indicates the mechanisms underlying oligodendrocyte differentiation and the influence of neurotransmitters on this process. The importance of action potentials and neurotransmission in neural function and the susceptibility of damaged nerve axons to ischemic or toxic damage is provided in detail. The potential of bionanotechnology for targeting neurodegenerative diseases using nanotechnology-based strategies, including polymeric, lipid-based, inorganic, organic, and biomimetic nanoparticles, suggests better management of neurodegenerative disorders.

CONCLUSION

While nanotechnology-based biomaterials show promise for targeted oligodendrocyte therapy in addressing neurodegenerative disorders linked to oligodendrocyte dysfunction, encapsulating neuroprotective agents within nanoparticles offers additional advantages. Nano-based delivery systems effectively protect drugs from degradation and prolong their therapeutic effects, holding promise in overcoming the blood-brain barrier by facilitating drug transport. However, a multifaceted approach is essential to enhance oligodendrocyte differentiation, promote myelin repair, and facilitate myelin dynamics with reduced toxicity. Further research is needed to elucidate the optimal therapeutic approaches and enhance patient outcomes.

Penumbra-targeted CircOGDH siRNA-loaded nanoparticles alleviate neuronal apoptosis in focal brain ischaemia

BACKGROUND

Nanoparticles (NPs) are a class of substances that can be loaded with therapeutic agents delivered to specific areas. In our earlier research, we identified a neuron-derived circular RNA (circRNA), circular oxoglutarate dehydrogenase (CircOGDH), as a promising therapeutic target for acute ischaemic stroke. This study dedicated to explore a prospective preliminary strategy of CircOGDH-based NP delivered to the ischaemic penumbra region in middle cerebral artery occlusion/reperfusion (MCAO/R) mice.

METHODS

Immunofluorescence in primary cortex neurons and in vivo fluorescence imaging revealed endocytosis of Poly(lactide-co-glycolide) (PLGA) poly amidoamine(PAMAM)@CircOGDH small interfering RNA (siRNA) NPs. Western blotting analysis and CCK8 assay were performed to evaluate the apoptotic level in ischaemic neurons treated with PLGA-PAMAM@CircOGDH siRNA NPs. Quantitative reverse transcription PCR experiments, mice behaviour test, T2 MRI analysis, Nissl and TdT-mediated dUTP nick end labeling (TUNEL) co-staining were performed to evaluate the apoptosis level of ischaemic penumbra neurons in MCAO/R mice. Biosafety evaluation of NPs in MCAO/R mice was detected by blood routine examination, liver and kidney function examination and HE staining.

RESULTS

PLGA-PAMAM@CircOGDH siRNA NPs were successfully assembled. Endocytosis of PLGA-PAMAM@CircOGDH siRNA NPs in ischaemic neurons alleviated neuronal apoptotic level in vitro and in vivo. Furthermore, mice behaviour test showed that the neurological defects of MCAO/R mice were significantly alleviated after the tail injection of PLGA-PAMAM@CircOGDH siRNA NPs, and no toxic effects were observed.

CONCLUSION

In conclusion, our results suggest that PLGA-PAMAM@CircOGDH siRNA NPs can be delivered to the ischaemic penumbra region and alleviate neuron apoptosis in MCAO/R mice and in ischaemic neurons; therefore, our study provides a desirable approach for using circRNA-based NPs for the treatment of ischaemic stroke.

Advanced Nano-Drug Delivery Systems in the Treatment of Ischemic Stroke

In recent years, the frequency of strokes has been on the rise year by year and has become the second leading cause of death around the world, which is characterized by a high mortality rate, high recurrence rate, and high disability rate. Ischemic strokes account for a large percentage of strokes. A reperfusion injury in ischemic strokes is a complex cascade of oxidative stress, neuroinflammation, immune infiltration, and mitochondrial damage. Conventional treatments are ineffective, and the presence of the blood-brain barrier (BBB) leads to inefficient drug delivery utilization, so researchers are turning their attention to nano-drug delivery systems. Functionalized nano-drug delivery systems have been widely studied and applied to the study of cerebral ischemic diseases due to their favorable biocompatibility, high efficiency, strong specificity, and specific targeting ability. In this paper, we briefly describe the pathological process of reperfusion injuries in strokes and focus on the therapeutic research progress of nano-drug delivery systems in ischemic strokes, aiming to provide certain references to understand the progress of research on nano-drug delivery systems (NDDSs).

Treatment of Ischemic Stroke by Atorvastatin-Loaded PEGylated Liposome

There is insufficient evidence on the effect of nanoparticles, particularly liposomes loaded with a statin, on acute ischemic stroke. We investigated the impact of atorvastatin-loaded PEG (polyethylene glycol) conjugated liposomes (LipoStatin) on the outcomes in rats with cerebral ischemia-reperfusion. PEGylated liposome loaded with atorvastatin was developed as a nanoparticle to specifically accumulate in an ischemic region and release the drug to ameliorate the harmful effects of the stroke. LipoStatin was administered to rats with transient middle cerebral artery occlusion through the tail vein immediately after reperfusion (LipoStatin group). LipoStatin efficiently accumulated at the cerebral ischemic injury site of the rat. The LipoStatin group showed a significantly reduced infarct volume (p < 0.01) in brain micro-MR imaging and improved neurological function recovery compared to the control group (p < 0.05). In addition, markedly improved brain metabolism using fluorine-18 fluorodeoxyglucose micro-PET/CT imaging was demonstrated in the LipoStatin group compared with the control group (p < 0.01). Mechanistically, as a result of evaluation through IL-1 beta, TNF-alpha, ICAM-1, and Iba-1 mRNA expression levels at 5 days after cerebral ischemia, LipoStatin showed significant anti-inflammatory effects. Protein expression of occludin, JAM-A, Caveolin-1, and eNOS by western blot at 3 days and fluorescent images at 7 days showed considerable recovery of blood-brain barrier breakdown and endothelial dysfunction. PEGylated LipoStatin can be more effectively delivered to the ischemic brain and may have significant neuroprotective effects. Thus, PEGylated LipoStatin can be further developed as a promising targeted therapy for ischemic stroke and other major vascular diseases.

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.

An Ultrasmall Cu/Cu2O Nanoparticle-Based Diselenide-Bridged Nanoplatform Mediating Reactive Oxygen Species Scavenging and Neuronal Membrane Enhancement for Targeted Therapy of Ischemic Stroke

Ischemic stroke is one of the major causes of death and disability worldwide, and an effective and timely treatment of ischemic stroke has been a challenge because of the narrow therapeutic window and the poor affinity with thrombus of the thrombolytic agent. In this study, rPZDCu, a multifunctional nanoparticle (NP) with the effects of thrombolysis, reactive oxygen species (ROS) scavenging, and neuroprotection, was synthesized based on an ultrasmall Cu4.6O NP, the thrombolytic agent rt-PA, and docosahexaenoic acid (DHA), which is a major component of the neuronal membrane. rPZDCu showed strong thrombus-targeting ability, which was achieved by the platelet cell membrane coating on the NP surface, and a good thrombolytic effect in both the common carotid artery clot model and embolic middle cerebral artery occlusion (MCAO) model of rats. Furthermore, rPZDCu exhibited a good escape from the phagocytosis of macrophages, effective promotion of the polarization of microglia, and efficient recovery of neurobiological and behavioral functions in the embolic MCAO model of rats. This is a heuristic report of (1) the Cu0/Cu+ NP for the treatments of brain diseases, (2) the integration of DHA and ROS scavengers for central nervous system therapies, and (3) diselenide-based ROS-responsive NPs for ischemic stroke treatments. This study also offers an example of cell membrane-camouflaged stimuli-responsive nanomedicine for brain-targeting drug delivery.

Recent progress in nanotechnology-based drug carriers for resveratrol delivery

Resveratrol is a polyphenol with diverse pharmacological activities, but its clinical efficacy is limited due to low solubility/permeability, light-induced isomerization, auto-oxidation, and rapid metabolism. Nanodelivery systems, such as liposomes, polymeric nanoparticles, lipid nanocarriers, micelles, nanocrystals, inorganic nanoparticles, nanoemulsions, protein-based nanoparticles, exosomes, macrophages, and red blood cells (RBCs) have shown great potential for improving the solubility, biocompatibility, and therapeutic efficacy of resveratrol. This review comprehensively summarizes the recent advances in resveratrol nanoencapsulation and describes potential strategies to improve the pharmacokinetics of existing nanoformulations, enhance targeting, reduce toxicity, and increase drug release and encapsulation efficiency. The article also suggests that in order to avoid potential safety issues, resveratrol nanoformulations must be tested in vivo in a wide range of diseases.

Potential regulatory effects of stem cell exosomes on inflammatory response in ischemic stroke treatment

The high incidence and disability rates of stroke pose a heavy burden on society. Inflammation is a significant pathological reaction that occurs after an ischemic stroke. Currently, therapeutic methods, except for intravenous thrombolysis and vascular thrombectomy, have limited time windows. Mesenchymal stem cells (MSCs) can migrate, differentiate, and inhibit inflammatory immune responses. Exosomes (Exos), which are secretory vesicles, have the characteristics of the cells from which they are derived, making them attractive targets for research in recent years. MSC-derived exosomes can attenuate the inflammatory response caused by cerebral stroke by modulating damage-associated molecular patterns. In this review, research on the inflammatory response mechanisms associated with Exos therapy after an ischemic injury is discussed to provide a new approach to clinical treatment.

Polylactic-co-glycolic acid-based nanoparticles modified with peptides and other linkers cross the blood-brain barrier for targeted drug delivery

Because of the blood-brain barrier, only a limited fraction of drugs can penetrate the brain. As a result, there is a need to take larger doses of the drug, which may result in numerous undesirable side effects. Over the past few decades, a plethora of research has been conducted to address this issue. In recent years, the field of nanomedicine research has reported promising findings. Currently, numerous types of polylactic-co-glycolic acid-based drug-delivery systems are being studied, and great progress has been made in the modification of their surfaces with a variety of ligands. In this review, the authors highlight the preparation of polylactic-co-glycolic acid-based nanoparticles and single- and dual-targeted peptide modifications for site-specific drug delivery into the brain.

Unveiling the Mechanism of Alleviating Ischemia Reperfusion Injury via a Layered Double Hydroxide-Based Nanozyme

Oxidative stress after ischemia reperfusion can cause irreversible brain damage. Thus, it is vital to timely consume excessive reactive oxygen species (ROS) and conduct molecular imaging monitoring on the brain injury site. However, previous studies have focused on how to scavenge ROS while ignoring the mechanism of relieving the reperfusion injury. Herein, we reported a layered double hydroxide (LDH)-based nanozyme (denoted as ALDzyme), which was fabricated by the confinement of astaxanthin (AST) with LDH. This ALDzyme can mimic natural enzymes, which include superoxide dismutase (SOD) and catalase (CAT). Furthermore, the SOD-like activity of ALDzyme is 16.3 times higher than that of CeO₂ (a typical ROS scavenger). Based on these enzyme-mimicking properties, this one-of-a-kind ALDzyme offers strong anti-oxidative properties as well as high biocompatibility. Importantly, this unique ALDzyme can establish an efficient magnetic resonance imaging platform, thus guiding the in vivo details. As a result, the infarct area can be reduced by 77% after reperfusion therapy, and the neurological impairment score can be lowered from 3-4 to 0-1. Density functional theory computations can reveal more about the mechanism of this ALDzyme's significant ROS consumption. These findings provide a method for unraveling the neuroprotection application process in ischemia reperfusion injury using an LDH-based nanozyme as a remedial nanoplatform.

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.