Advanced drug delivery system against ischemic stroke

Drug delivery under cover of erythrocytes extends drug half-life: A thrombolytic targeting therapy utilizing microenvironment-responsive artificial polysaccharide microvesicles

The development of thrombolytic drug carriers capable of thrombus-targeting, prolonged circulation time, intelligent responsive release, and the ability to inhibit thrombotic recurrences remains a promising but significant challenge. To tackle this, an artificial polysaccharide microvesicle drug delivery system (uPA-CS/HS@RGD-ODE) was constructed. It is composed of cationic chitosan and anionic heparin assembled in a layer by layer structure, followed by surface modification using RGD peptide and 2-(N-oxide-N,N-diethylamino) ethylmethacrylate (ODE) before encapsulation of urokinase-type plasminogen activator (uPA). The effect of chitosan on the basic performances of uPA-CS/HS@RGD-ODE was estimated. The in vitro results suggest the uPA carrier, CS/HS@RGD-ODE, displayed outstanding targeting specific to activated platelets (61 %) and microenvironment-responsiveness at pH 6.5, facilitating thrombus-targeting and a controlled drug release, respectively. Most importantly, in vivo experiment suggests ODE from uPA-CS/HS@RGD-ODE substantially extends the half-life of uPA (120 min), as uPA-CS/HS@RGD-ODE can adhere onto erythrocytes and deliver uPA under cover of erythrocytes enabling a prolonged circulation time in the bloodstream. Further tail vein and abdominal aorta thrombosis models confirmed uPA-CS/HS@RGD-ODE exhibited superior targeting and thrombolysis capabilities compared to systemic administration of free uPA. To the knowledge of authors, this may be the first study to develop new drug carriers for delivery of thrombolytic drugs under the cover of erythrocytes for extended drug half-lives.

Ischemic Microenvironment-Targeted Bioinspired Lipoprotein Sequentially Penetrates Cerebral Ischemic Lesions to Rescue Ischemic Stroke

Reperfusion injury represents a significant impediment to recovery after recanalization in an ischemic stroke and can be alleviated by neuroprotectants. However, inadequate drug delivery to ischemic lesions impairs the therapeutic effects of neuroprotectants. To address this issue, an ischemic microenvironment-targeted bioinspired lipoprotein system encapsulating lipoic acid (LA@PHDL) is herein designed to sequentially penetrate ischemic lesions and be readily taken up by neurons and microglia. In transient middle cerebral artery occlusion (tMCAO) mouse models, LA@PHDL accumulates rapidly and preferentially in the ischemic brain, with a 2.29-fold higher than the nontargeted nanoplatform in the early stage. Furthermore, LA@PHDL effectively restores neurological function, reduces infarct volume to 17.70%, prevents brain cell necrosis and apoptosis, and attenuates inflammation in tMCAO mouse models. This design presents new opportunities for delivering neuroprotectants to cerebral ischemic lesions to improve the outcome of an ischemic stroke.

The Role of Mitochondrial Pyruvate Carrier in Neurological Disorders

The mitochondrial pyruvate carrier (MPC) is a specific protein complex located in the inner mitochondrial membrane. Comprising a heterodimer of two homodimeric membrane proteins, mitochondrial pyruvate carrier 1 and mitochondrial pyruvate carrier 2, MPC connects cytoplasmic metabolism to mitochondrial metabolism by transferring pyruvate from the cytoplasm to the mitochondria. The nervous system requires substantial energy to maintain its function, and the mitochondrial energy supply is closely linked to neurological function. Mitochondrial dysfunction can induce or exacerbate intracerebral pathologies. MPC influences mitochondrial function due to its specific role as a pyruvate transporter. However, recent studies on MPC and mitochondrial dysfunction in neurological disorders have yielded controversial results, and the underlying mechanisms remain unclear. In this brief review, we provide an overview of the structure and function of MPC. We further discuss the potential mechanisms and feasibility of targeting MPC in treating Parkinson's disease, Alzheimer's disease, and cerebral ischemia/hypoxia injury. This review aims to offer insights into MPC as a target for clinical treatment.

Application and Development of Cell Membrane Functionalized Biomimetic Nanoparticles in the Treatment of Acute Ischemic Stroke

Ischemic stroke is a serious neurological disease involving multiple complex physiological processes, including vascular obstruction, brain tissue ischemia, impaired energy metabolism, cell death, impaired ion pump function, and inflammatory response. In recent years, there has been significant interest in cell membrane-functionalized biomimetic nanoparticles as a novel therapeutic approach. This review comprehensively explores the mechanisms and importance of using these nanoparticles to treat acute ischemic stroke with a special emphasis on their potential for actively targeting therapies through cell membranes. We provide an overview of the pathophysiology of ischemic stroke and present advances in the study of biomimetic nanoparticles, emphasizing their potential for drug delivery and precision-targeted therapy. This paper focuses on bio-nanoparticles encapsulated in bionic cell membranes to target ischemic stroke treatment. It highlights the mechanism of action and research progress regarding different types of cell membrane-functionalized bi-onic nanoparticles such as erythrocytes, neutrophils, platelets, exosomes, macrophages, and neural stem cells in treating ischemic stroke while emphasizing their potential to improve brain tissue's ischemic state and attenuate neurological damage and dysfunction. Through an in-depth exploration of the potential benefits provided by cell membrane-functionalized biomimetic nanoparticles to improve brain tissue's ischemic state while reducing neurological injury and dysfunction, this study also provides comprehensive research on neural stem cells' potential along with that of cell membrane-functionalized biomimetic nanoparticles to ameliorate neurological injury and dysfunction. However, it is undeniable that there are still some challenges and limitations in terms of biocompatibility, safety, and practical applications for clinical translation.

Fibrinogen binding to activated platelets and its biomimetic thrombus-targeted thrombolytic strategies

Thrombosis is associated with various fatal arteriovenous syndromes including ischemic stroke, myocardial infarction, and pulmonary embolism. However, current clinical thrombolytic treatment strategies still have many problems in targeting and safety to meet the thrombolytic therapy needs. Understanding the molecular mechanism that underlies thrombosis is critical in developing effective thrombolytic strategies. It is well known that platelets play a central role in thrombosis and the binding of fibrinogen to activated platelets is a common pathway in the process of clot formation. Based on this, a concept of biomimetic thrombus-targeted thrombolytic strategy inspired from fibrinogen binding to activated platelets in thrombosis was proposed, which could selectively bind to activated platelets at a thrombus site, thus enabling targeted delivery and local release of thrombolytic agents for effective thrombolysis. In this review, we first summarized the main characteristics of platelets and fibrinogen, and then introduced the classical molecular mechanisms of thrombosis, including platelet adhesion, platelet activation and platelet aggregation through the interactions of activated platelets with fibrinogen. In addition, we highlighted the recent advances in biomimetic thrombus-targeted thrombolytic strategies which inspired from fibrinogen binding to activated platelets in thrombosis. The possible future directions and perspectives in this emerging area are briefly discussed.

Tea polyphenol-derived nanomedicine for targeted photothermal thrombolysis and inflammation suppression

Thrombotic diseases impose a significant global health burden, and conventional drug-based thrombolytic therapies are encumbered by the risk of bleeding complications. In this study, we introduce a novel drug-free nanomedicine founded on tea polyphenols nanoparticles (TPNs), which exhibits multifaceted capabilities for localized photothermal thrombolysis. TPNs were synthesized through a one-pot process under mild conditions, deriving from the monomeric epigallocatechin-3-gallate (EGCG). Within this process, indocyanine green (ICG) was effectively encapsulated, exploiting multiple intermolecular interactions between EGCG and ICG. While both TPNs and ICG inherently possessed photothermal potential, their synergy significantly enhanced photothermal conversion and stability. Furthermore, the nanomedicine was functionalized with cRGD for targeted delivery to activated platelets within thrombus sites, eliciting robust thrombolysis upon laser irradiation across diverse thrombus types. Importantly, the nanomedicine's potent free radical scavenging abilities concurrently mitigated vascular inflammation, thus diminishing the risk of disease recurrence. In summary, this highly biocompatible multifunctional nanomaterial holds promise as a comprehensive approach that combines thrombolysis with anti-inflammatory actions, offering precision in thrombosis treatment.

Perspective insights into versatile hydrogels for stroke: From molecular mechanisms to functional applications

As the leading killer of life and health, stroke leads to limb paralysis, speech disorder, dysphagia, cognitive impairment, mental depression and other symptoms, which entail a significant financial burden to society and families. At present, physiology, clinical medicine, engineering, and materials science, advanced biomaterials standing on the foothold of these interdisciplinary disciplines provide new opportunities and possibilities for the cure of stroke. Among them, hydrogels have been endowed with more possibilities. It is well-known that hydrogels can be employed as potential biosensors, medication delivery vectors, and cell transporters or matrices in tissue engineering in tissue engineering, and outperform many traditional therapeutic drugs, surgery, and materials. Therefore, hydrogels become a popular scaffolding treatment option for stroke. Diverse synthetic hydrogels were designed according to different pathophysiological mechanisms from the recently reported literature will be thoroughly explored. The biological uses of several types of hydrogels will be highlighted, including pro-angiogenesis, pro-neurogenesis, anti-oxidation, anti-inflammation and anti-apoptosis. Finally, considerations and challenges of using hydrogels in the treatment of stroke are summarized.

Long-circulating nanoparticles as passive targeting nanocarriers for the treatment of thrombosis

Thrombosis is the major cause of cardiovascular diseases. Only a small subset of patients could benefit from thrombolytic therapy due to the high bleeding risk brought about by the repeated administration of thrombolytic drugs. Nanoparticles with targeting ligands have been developed as nanocarriers of thrombolytic drugs to deliver the drug to the thrombus through active targeting. However, the passive targeting effect of nanoparticles on the thrombus is yet to be investigated. Herein, we prepared silica cross-linked micelles (SCLMs) with a long blood circulation half-life as drug carriers to target the thrombus through passive targeting. Compared with SCLMs modified with an active targeting ligand cRGD, the SCLMs exhibited similar targeting behavior to the thrombus in vivo. Loaded with the thrombolytic drug tirofiban, the passive targeting SCLMs showed a comparable therapeutic effect to cRGD-modified SCLMs in a mice model with pulmonary embolism and arterial thrombosis.

Nanomaterial-Based Drug Delivery Systems for Ischemic Stroke

Ischemic stroke is a leading cause of death and disability in the world. At present, reperfusion therapy and neuroprotective therapy, as guidelines for identifying effective and adjuvant treatment methods, are limited by treatment time windows, drug bioavailability, and side effects. Nanomaterial-based drug delivery systems have the characteristics of extending half-life, increasing bioavailability, targeting drug delivery, controllable drug release, and low toxicity, thus being used in the treatment of ischemic stroke to increase the therapeutic effects of drugs. Therefore, this review provides a comprehensive overview of nanomaterial-based drug delivery systems from nanocarriers, targeting ligands and stimulus factors of drug release, aiming to find the best combination of nanomaterial-based drug delivery systems for ischemic stroke. Finally, future research areas on nanomaterial-based drug delivery systems in ischemic stroke and the implications of the current knowledge for the development of novel treatment for ischemic stroke were identified.

Application of omics technology to investigate the mechanism underlying the role of San Hua Tang in regulating microglia polarization and blood-brain barrier protection following ischemic stroke

ETHNOPHARMACOLOGY RELEVANCE

San Hua Tang (SHT) was first mentioned in the book "The Collection of Plain Questions about Pathogenesis, Qi, and Life." SHT has the effect of dispelling wind and dredging collaterals, dredging viscera, and guiding stagnation, and is used in the treatment of ischemic stroke (IS). SHT is composed of Rheum palmatum L., Magnolia officinalis Rehder & E.H.Wilson, Citrus assamensis S.Dutta & S.C.Bhattacharya, and Notopterygium tenuifolium M.L.Sheh & F.T.Pu, which is the traditional prescription of the Tongxia method for the treatment of stroke. Tongxia is one of the "eight methods" used in traditional Chinese medicine, which plays a role in treating diseases by promoting gastrointestinal peristalsis and defecation. Studies have demonstrated a close relationship between gut microbiota metabolism and cerebral stroke; however, the role of SHT in IS treatment through gut microbiota or intestinal metabolites is unclear.

AIM OF THE STUDY

To explore the connotation of the Xuanfu theory and clarify the mechanism underlying SHT-mediated opening Xuanfu methods. Through metabolomics, 16S rRNA gene sequencing, and molecular biology techniques, research on the changes in the gut microbiota and blood-brain barrier (BBB) will highlight greater strategies for the treatment of stroke.

MATERIALS AND METHODS

We used pseudo-germ-free (PGF) rats combined with an ischemia/reperfusion (I/R) rat model for the follow-up experimental research. PGF rats were prepared by the intragastric administration of an antibiotic cocktail for 6 days, following which SHT was administered for 5 consecutive days. The I/R model was performed 1 day following the concluding administration of SHT. We detected the neurological deficit score, cerebral infarct volume, serum inflammatory factor levels (interleukin IL-6, IL-10, IL-17, and tumor necrosis factor alpha), tight junction-related proteins (Zonula occludens-1, Occludin, and Claudin-5), and small glue plasma cell-associated proteins (Cluster of Differentiation 16/Cluster of Differentiation 206, Matrix metalloproteinase, ionized calcium-binding adapter molecule 1, and C-X3-C Motif Chemokine Ligand 1) 24 h following I/R. Using 16S rRNA gene sequencing and non-targeted metabolomics analysis, we explored the relationship between fecal microecology and serum metabolites. Eventually, we analyzed the correlation between the gut microbiota and plasma metabolic profile as well as the mechanism underlying the SHT-mediated regulation of gut microbiota to protect the BBB following stroke.

RESULTS

In IS treatment, SHT is principally involved in reducing neurological injury and the volume of cerebral infarction; protecting the intestinal mucosal barrier; increasing the levels of acetic acid, butyric acid, and propionic acid; promoting the transformation of microglia to the M2 state; reducing inflammatory reactions; and enhancing tight junctions. These therapeutic effects were not observed in the group treated with antibiotics alone or that treated with SHT in combination with antibiotics, thereby indicating SHT plays a therapeutic role through the gut microbiota.

CONCLUSION

SHT regulates the gut microbiota, inhibits pro-inflammatory factors in rats with IS, alleviates an inflammatory injury of the BBB, and plays a protective role in the brain.

Surface-tethered ROS-responsive micelle backpacks for boosting mesenchymal stem cell vitality and modulating inflammation in ischemic stroke treatment

Mesenchymal stem cells (MSCs) exhibited remarkable therapeutic potential in ischemic stroke due to their exceptional immunomodulatory ability and paracrine effect; they have also been regarded as excellent neuroprotectant delivery vehicles with inflammatory tropism. However, the presence of high levels of reactive oxygen species (ROS) and an oxidative stress environment at the lesion site inhibits cell survival and further therapeutic effects. Using bioorthogonal click chemistry, ROS-responsive luteolin-loaded micelles were tethered to the surface of MSCs. As MSCs migrated to the ischemic brain, the micelles would achieve ROS-responsive release of luteolin to protect MSCs from excessive oxidative damage while inhibiting neuroinflammation and scavenging ROS to ameliorate ischemic stroke. This study provided an effective and prospective therapeutic strategy for ischemic stroke and a framework for a stem cell-based therapeutic system to treat inflammatory cerebral diseases.

P-Selectin mediates targeting of a self-assembling phototherapeutic nanovehicle enclosing dipyridamole for managing thromboses

Thrombotic vascular disorders, specifically thromboembolisms, have a significant detrimental effect on public health. Despite the numerous thrombolytic and antithrombotic drugs available, their efficacy in penetrating thrombus formations is limited, and they carry a high risk of promoting bleeding. Consequently, the current medication dosage protocols are inadequate for preventing thrombus formation, and higher doses are necessary to achieve sufficient prevention. By integrating phototherapy with antithrombotic therapy, this study addresses difficulties related to thrombus-targeted drug delivery. We developed self-assembling nanoparticles (NPs) through the optimization of a co-assembly engineering process. These NPs, called DIP-FU-PPy NPs, consist of polypyrrole (PPy), dipyridamole (DIP), and P-selectin-targeted fucoidan (FU) and are designed to be delivered directly to thrombi. DIP-FU-PPy NPs are proposed to offer various potentials, encompassing drug-loading capability, targeted accumulation in thrombus sites, near-infrared (NIR) photothermal-enhanced thrombus management with therapeutic efficacy, and prevention of rethrombosis. As predicted, DIP-FU-PPy NPs prevented thrombus recurrence and emitted visible fluorescence signals during thrombus clot penetration with no adverse effects. Our co-delivery nano-platform is a simple and versatile solution for NIR-phototherapeutic multimodal thrombus control.

Neutrophil membrane fusogenic nanoliposomal leonurine for targeted ischemic stroke therapy via remodeling cerebral niche and restoring blood-brain barrier integrity

Ischemic stroke (IS) constitutes the leading cause of global morbidity and mortality. Neuroprotectants are essential to ameliorate the clinical prognosis, but their therapeutic outcomes are tremendously compromised by insufficient delivery to the ischemic lesion and intricate pathogenesis associated with neuronal damage, oxidative stress, inflammation responses, blood-brain barrier (BBB) dysfunction, etc. Herein, a biomimetic nanosystem (Leo@NM-Lipo) composed of neutrophil membrane-fused nanoliposomal leonurine (Leo) is constructed, which can not only efficiently penetrate and repair the disrupted BBB but also robustly remodel the harsh cerebral microenvironment to reverse ischemia-reperfusion (I/R) injury. More specifically, the neutrophil membrane inherits the BBB penetrating, infarct core targeting, inflammation neutralization, and immune evasion properties of neutrophils, while Leo, a naturally occurring neuroprotectant, exerts pleiotropic effects to attenuate brain damage. Remarkably, comprehensive investigations disclose the critical factors influencing the targetability and therapeutic performances of biomimetic nanosystems. Leo@NM-Lipo with a low membrane protein-to-lipid ratio of 1:10 efficiently targets the ischemic lesion and rescues the injured brain by alleviating neuronal apoptosis, oxidative stress, neuroinflammation, and restoring BBB integrity in transient middle cerebral artery occlusion (tMCAO) rats. Taken together, our study provides a neutrophil-mimetic nanoplatform for targeted IS therapy and sheds light on the rational design of biomimetic nanosystems favoring wide medical applications.

Controlled growth of titanium dioxide nanotubes for doxorubicin loading and studies of in vitro antitumor activity

Titanium dioxide (TiO₂) materials are suitable for use as drug carriers due to their natural biocompatibility and nontoxicity. The aim of the study presented in this paper was to investigate the controlled growth of TiO₂ nanotubes (TiO₂ NTs) of different sizes via an anodization method, in order to delineate whether the size of NTs governs their drug loading and release profile as well as their antitumor efficiency. TiO₂ NTs were tailored to sizes ranging from 25 nm to 200 nm according to the anodization voltage employed. The TiO₂ NTs obtained by this process were characterized using scanning electron microscopy, transmission electron microscopy, and dynamic light scattering The larger TiO₂ NTs exhibited greatly improved doxorubicin (DOX)-loading capacity (up to 37.5 wt%), which contributed to their outstanding cell-killing ability, as evidenced by their lower half-maximal inhibitory concentration (IC50). Comparisons were carried out of cellular uptake and intracellular release rates of DOX for large and small TiO₂ NTs loaded with DOX. The results showed that the larger TiO₂ NTs represent a promising therapeutic carrier for drug loading and controlled release, which could improve cancer treatment outcomes. Therefore, TiO₂ NTs of larger size are useful substances with drug-loading potency that may be used in a wide range of medical applications.

A generalizable strategy for crosslinkable albumin-based hydrogels and application as potential anti-tumor nanoplatform

Albumin-based hydrogels have emerged as promising nanoparticle systems for the effective delivery of hydrophobic anticancer drugs. Anti-cancer drugs often cause some adverse effects, such as toxicity and rapid clearance by mononuclear phagocytic systems. Herein, a new strategy of synthesizing N-hydroxysuccinimide (NHS)-activated linker to form crosslinkable albumin-based hydrogels (CABH) is reported. The CABH favored physiochemical characteristics improvement of doxorubicin (Dox) and drug release. The CABH was constructed depending on the crosslinking reaction between NHS activated glycerol and albumin. The size of CABH was approximately 200 nm examined by dynamic light scattering (DLS) and transmission electron microscopy (TEM). It was found that the particle size and size distribution of the CABH remained stable in neutral PBS for 1 week. Dox loaded CABH would be controllably released in weak acidic environment verified by in vitro release and in vitro cell imaging. The Dox loaded hydrogel results in significant killing in the case of acidic culture medium. Our work provides a crosslinking method to formulate albumin nanoplatform and improve the size, stability, drug loading capacity and controlled release, which throws light on the potential application in drug delivery.

Stimuli-Responsive Nanotherapeutics for Treatment and Diagnosis of Stroke

Stroke is the second most common medical emergency and constitutes a significant cause of global morbidity. The conventional stroke treatment strategies, including thrombolysis, antiplatelet therapy, endovascular thrombectomy, neuroprotection, neurogenesis, reducing neuroinflammation, oxidative stress, excitotoxicity, hemostatic treatment, do not provide efficient relief to the patients due to lack of appropriate delivery systems, large doses, systemic toxicity. In this context, guiding the nanoparticles toward the ischemic tissues by making them stimuli-responsive can be a turning point in managing stroke. Hence, in this review, we first outline the basics of stroke, including its pathophysiology, factors affecting its development, current treatment therapies, and their limitations. Further, we have discussed stimuli-responsive nanotherapeutics used for diagnosing and treating stroke with challenges ahead for the safe use of nanotherapeutics.

Traditional Chinese medicine in treating ischemic stroke by modulating mitochondria: A comprehensive overview of experimental studies

Ischemic stroke has been a prominent focus of scientific investigation owing to its high prevalence, complex pathogenesis, and difficulties in treatment. Mitochondria play an important role in cellular energy homeostasis and are involved in neuronal death following ischemic stroke. Hence, maintaining mitochondrial function is critical for neuronal survival and neurological improvement in ischemic stroke, and mitochondria are key therapeutic targets in cerebral stroke research. With the benefits of high efficacy, low cost, and high safety, traditional Chinese medicine (TCM) has great advantages in preventing and treating ischemic stroke. Accumulating studies have explored the effect of TCM in preventing and treating ischemic stroke from the perspective of regulating mitochondrial structure and function. In this review, we discuss the molecular mechanisms by which mitochondria are involved in ischemic stroke. Furthermore, we summarized the current advances in TCM in preventing and treating ischemic stroke by modulating mitochondria. We aimed to provide a new perspective and enlightenment for TCM in the prevention and treatment of ischemic stroke by modulating mitochondria.

Novel Immobilized Biocatalysts Based on Cysteine Proteases Bound to 2-(4-Acetamido-2-sulfanilamide) Chitosan and Research on Their Structural Features

Briefly, 2-(4-Acetamido-2-sulfanilamide) chitosan, which is a chitosan water-soluble derivative, with molecular weights of 200, 350, and 600 kDa, was successfully synthesized. The immobilization of ficin, papain, and bromelain was carried out by complexation with these polymers. The interaction mechanism of 2-(4-acetamido-2-sulfanilamide) chitosan with bromelain, ficin, and papain was studied using FTIR spectroscopy. It was found that the hydroxy, thionyl, and amino groups of 2-(4-acetamido-2-sulfanilamide) chitosan were involved in the complexation process. Molecular docking research showed that all amino acid residues of the active site of papain formed hydrogen bonds with the immobilization matrix, while only two catalytically valuable amino acid residues took part in the H-bond formation for bromelain and ficin. The spectral and in silico data were in good agreement with the catalytic activity evaluation data. Immobilized papain was more active compared to the other immobilized proteases. Moreover, the total and specific proteolytic activity of papain immobilized on the carrier with a molecular weight of 350 kDa were higher compared to the native one due to the hyperactivation. The optimal ratio of protein content (mg × g ⁻¹ of carrier), total activity (U × mL⁻¹ of solution), and specific activity (U × mg⁻¹ of protein) was determined for the enzymes immobilized on 2-(4-acetamido-2-sulfanilamide) chitosan with a molecular weight of 350 kDa.