A single injection of liposomal asialo-erythropoietin improves motor function deficit caused by cerebral ischemia/reperfusion

Innovations in Breaking Barriers: Liposomes as Near-Perfect Drug Carriers in Ischemic Stroke Therapy

Liposomes, noted for their tunable particle size, surface customization, and varied drug delivery capacities, are increasingly acknowledged in therapeutic applications. These vesicles exhibit surface flexibility, enabling the incorporation of targeting moieties or peptides to achieve specific targeting and avoid lysosomal entrapment. Internally, their adaptable architecture permits the inclusion of a broad spectrum of drugs, contingent on their solubility characteristics. This study thoroughly reviews liposome fabrication, surface modifications, and drug release mechanisms post-systemic administration, with a particular emphasis on drugs crossing the blood-brain barrier (BBB) to address lesions. Additionally, the review delves into recent developments in the use of liposomes in ischemic stroke models, offering a comparative evaluation with other nanocarriers like exosomes and nano-micelles, thereby facilitating their clinical advancement.

Targeted delivery of edaravone by liposomes for the treatment of ischemic stroke

Aim: To construct an edaravone-encapsulated liposomes (EDV-LIPs) formulation against acute ischemic stroke. Methods: EDV-LIPs were prepared by the film dispersion method. The biosafety was evaluated both in vitro and in vivo by flow cytometry and the histological staining method. Biodistribution and therapeutic effect of EDV-LIPs against acute ischemic stroke was investigated by fluorescent imaging, the behavior test, laser speckle imaging and triphenyltetrazolium chloride staining. Results: The nanoliposomes had a long circulation time and could accumulate in the brain lesion region in ischemic stroke rats. EDV-LIPs show good biosafety. EDV-LIPs could restore more cerebral blood flow, reduce infarct volume and decrease neuronal apoptosis. Conclusion: EDV-LIPs provide an effective alternative for drug-targeted delivery against acute ischemic stroke.

The Effect of Erythropoietin and Its Derivatives on Ischemic Stroke Therapy: A Comprehensive Review

Numerous studies explored the therapeutic effects of erythropoietin (EPO) on neurodegenerative diseases. Few studies provided comprehensive and latest knowledge of EPO treatment for ischemic stroke. In the present review, we introduced the structure, expression, function of EPO, and its receptors in the central nervous system. Furthermore, we comprehensively discussed EPO treatment in pre-clinical studies, clinical trials, and its therapeutic mechanisms including suppressing inflammation. Finally, advanced studies of the therapy of EPO derivatives in ischemic stroke were also discussed. We wish to provide valuable information on EPO and EPO derivatives’ treatment for ischemic stroke for basic researchers and clinicians to accelerate the process of their clinical applications.

Application and Utility of Liposomal Neuroprotective Agents and Biomimetic Nanoparticles for the Treatment of Ischemic Stroke

Ischemic stroke is still one of the leading causes of high mortality and severe disability worldwide. Therapeutic options for ischemic stroke and subsequent cerebral ischemia/reperfusion injury remain limited due to challenges associated with drug permeability through the blood-brain barrier (BBB). Neuroprotectant delivery with nanoparticles, including liposomes, offers a promising solution to address this problem, as BBB disruption following ischemic stroke allows nanoparticles to pass through the intercellular gaps between endothelial cells. To ameliorate ischemic brain damage, a number of nanotherapeutics encapsulating neuroprotective agents, as well as surface-modified nanoparticles with specific ligands targeting the injured brain regions, have been developed. Combination therapy with nanoparticles encapsulating neuroprotectants and tissue plasminogen activator (t-PA), a globally approved thrombolytic agent, has been demonstrated to extend the narrow therapeutic time window of t-PA. In addition, the design of biomimetic drug delivery systems (DDS) employing circulating cells (e.g., leukocytes, platelets) with unique properties has recently been investigated to overcome the injured BBB, utilizing these cells’ inherent capability to penetrate the ischemic brain. Herein, we review recent findings on the application and utility of nanoparticle DDS, particularly liposomes, and various approaches to developing biomimetic DDS functionalized with cellular membranes/membrane proteins for the treatment of ischemic stroke.

Recent advances in nanomedicines for the treatment of ischemic stroke

Ischemic stroke is a cerebrovascular disease normally caused by interrupted blood supply to the brain. Ischemia would initiate the cascade reaction consisted of multiple biochemical events in the damaged areas of the brain, where the ischemic cascade eventually leads to cell death and brain infarction. Extensive researches focusing on different stages of the cascade reaction have been conducted with the aim of curing ischemic stroke. However, traditional treatment methods based on antithrombotic therapy and neuroprotective therapy are greatly limited for their poor safety and treatment efficacy. Nanomedicine provides new possibilities for treating stroke as they could improve the pharmacokinetic behavior of drugs in vivo, achieve effective drug accumulation at the target site, enhance the therapeutic effect and meanwhile reduce the side effect. In this review, we comprehensively describe the pathophysiology of stroke, traditional treatment strategies and emerging nanomedicines, summarize the barriers and methods for transporting nanomedicine to the lesions, and illustrate the latest progress of nanomedicine in treating ischemic stroke, with a view to providing a new feasible path for the treatment of cerebral ischemia.

Physiological and Pathological Factors Affecting Drug Delivery to the Brain by Nanoparticles

The prevalence of neurological/neurodegenerative diseases, such as Alzheimer's disease is known to be increasing due to an aging population and is anticipated to further grow in the decades ahead. The treatment of brain diseases is challenging partly due to the inaccessibility of therapeutic agents to the brain. An increasingly important observation is that the physiology of the brain alters during many brain diseases, and aging adds even more to the complexity of the disease. There is a notion that the permeability of the blood-brain barrier (BBB) increases with aging or disease, however, the body has a defense mechanism that still retains the separation of the brain from harmful chemicals in the blood. This makes drug delivery to the diseased brain, even more challenging and complex task. Here, the physiological changes to the diseased brain and aged brain are covered in the context of drug delivery to the brain using nanoparticles. Also, recent and novel approaches are discussed for the delivery of therapeutic agents to the diseased brain using nanoparticle based or magnetic resonance imaging guided systems. Furthermore, the complement activation, toxicity, and immunogenicity of brain targeting nanoparticles as well as novel in vitro BBB models are discussed.

The Role of Nanomaterials in Stroke Treatment: Targeting Oxidative Stress

Stroke has a high rate of morbidity and disability, which seriously endangers human health. In stroke, oxidative stress leads to further damage to the brain tissue. Therefore, treatment for oxidative stress is urgently needed. However, antioxidative drugs have demonstrated obvious protective effects in preclinical studies, but the clinical studies have not seen breakthroughs. Nanomaterials, with their characteristically small size, can be used to deliver drugs and have demonstrated excellent performance in treating various diseases. Additionally, some nanomaterials have shown potential in scavenging reactive oxygen species (ROS) in stroke according to the nature of nanomaterials. The drugs' delivery ability of nanomaterials has great significance for the clinical translation and application of antioxidants. It increases drug blood concentration and half-life and targets the ischemic brain to protect cells from oxidative stress-induced death. This review summarizes the characteristics and progress of nanomaterials in the application of antioxidant therapy in stroke, including ischemic stroke, hemorrhagic stroke, and neural regeneration. We also discuss the prospect of nanomaterials for the treatment of oxidative stress in stroke and the challenges in their application, such as the toxicity and the off-target effects of nanomaterials.

Correction of morphofunctional disorders of the cardiovascular system with asialized erythropoietin and arginase II selective inhibitors KUD 974 and KUD 259 in experimental preeclampsia

Introduction: Preeclampsia remains one of the most common causes of maternal and perinatal mortality worldwide. A significant role in the pathogenesis of this pathology is assigned to placental ischemia and endothelial dysfunction. Therefore, the aim of the present study was to study the effectiveness of asialized erythropoietin and arginase II selective inhibitors: KUD-259 and KUD-974 in the correction of morphofunctional disorders of the cardiovascular system in experimental preeclampsia.

Materials and methods: The study was performed in 260 female Wistar rats, each weighing 250–300 g. An ADMA-like preeclampsia was reproduced in the experiment. To assess the emerging morphofunctional disorders, the following parameters were used: blood pressure, coefficient of endothelial dysfunction, microcirculation in the placenta, proteinuria, fluid content in the omentum, concentration of terminal metabolites in the blood plasma, and morphometric parameters of fetuses.

Results and discussion: The administration of arginase II selective inhibitor KUD-974 in combination with asialized erythropoietin leads to a pronounced correction of emerging changes: a decrease in systolic and diastolic blood pressure in 1.5 and 1.7 times, a decrease in proteinuria in 3.6 times and a decrease in fluid content in the omentum. When arginase II selective inhibitor KUD 974 and asialized erythropoietin are used with methyldopa, the positive effects of the former are enhanced.

Conclusion: Arginase II selective inhibitors KUD-259 and KUD-974 and asialized erythropoietin have a pronounced positive effect on the correction of morphofunctional disorders in animals with ADMA-like preeclampsia.

Potential application of liposomal nanodevices for non-cancer diseases: an update on design, characterization and biopharmaceutical evaluation

Liposomes, lipid-based vesicular systems, have attracted major interest as a means to improve drug delivery to various organs and tissues in the human body. Recent literature highlights the benefits of liposomes for use as drug delivery systems, including encapsulating of both hydrophobic and hydrophilic cargos, passive and active targeting, enhanced drug bioavailability and therapeutic effects, reduced systemic side effects, improved cargo penetration into the target tissue and triggered contents release. Pioneering work of liposomes researchers led to introduction of long-circulating, ligand-targeted and triggered release liposomes, as well as, liposomes containing nucleic acids and vesicles containing combination of cargos. Altogether, these findings have led to widespread application of liposomes in a plethora of areas from cancer to conditions such as cardiovascular, neurologic, respiratory, skin, autoimmune and eye disorders. There are numerous review articles on the application of liposomes in treatment of cancer, which seems the primary focus, whereas other diseases also benefit from liposome-mediated treatments. Therefore, this article provides an illustrated detailed overview of liposomal formulations, in vitro characterization and their applications in different disorders other than cancer. Challenges and future directions, which must be considered to obtain the most benefit from applications of liposomes in these disorders, are discussed.

Novel approaches for the delivery of therapeutics in ischemic stroke

Here, we review novel approaches to deliver neuroprotective drugs to salvageable penumbral brain areas of stroke injury with the goals of offsetting ischemic brain injury and enhancing recovery.

Nanocarriers for Stroke Therapy: Advances and Obstacles in Translating Animal Studies

The technology of drug delivery systems (DDS) has expanded into many applications, such as for treating neurological disorders. Nanoparticle DDS offer a unique strategy for targeted transport and improved outcomes of therapeutics. Stroke is likely to benefit from the emergence of this technology though clinical breakthroughs are yet to manifest. This review explores the recent advances in this field and provides insight on the trends, prospects and challenges of translating this technology to clinical application. Carriers of diverse material compositions are presented, with special focus on the surface properties and emphasis on the similarities and inconsistencies among in vivo experimental paradigms. Research attention is scattered among various nanoparticle DDS and various routes of drug administration, which expresses the lack of consistency among studies. Analysis of current literature reveals lipid- and polymer-based DDS as forerunners of DDS for stroke; however, cell membrane-derived vesicles (CMVs) possess the competitive edge due to their innate biocompatibility and superior efficacy. Conversely, inorganic and carbon-based DDS offer different functionalities as well as varied capacity for loading but suffer mainly from poor safety and general lack of investigation in this area. This review supports the existing literature by systematizing presently available data and accounting for the differences in drugs of choice, carrier types, animal models, intervention strategies and outcome parameters.

Applications of Liposomal Drug Delivery Systems to Develop Neuroprotective Agents for the Treatment of Ischemic Stroke

Ischemic stroke is one of the leading causes of severe disability and death. In clinical settings, tissue plasminogen activator (t-PA) for thrombolytic therapy is the only globally approved drug for the treatment of ischemic stroke. However, the proportion of patients who receive t-PA therapy is extremely limited due to its narrow therapeutic time window (TTW) and the risk of cerebral hemorrhage. Cerebral ischemia-reperfusion (I/R) injury is also a serious problem for patients' outcomes. Hence, the development of more effective therapies has been desired to prolong the TTW of t-PA and prevent cerebral I/R injury. For delivering drugs into the brain, the blood-brain barrier (BBB) must be overcome since it limits drug penetration into the brain, leading to insufficient therapeutic efficacy. As a distinctive pathology after an ischemic stroke, it was reported that the vascular permeability of the BBB is increased around the ischemic region. We found that nano-sized liposomes can pass through the disrupted BBB and accumulate in the I/R region, and that delivery of neuroprotective agents using a liposomal drug delivery system (DDS) is effective for the treatment of cerebral I/R injury. Moreover, we have recently demonstrated that combination therapy with liposomal drugs and t-PA can suppress the deleterious effects of t-PA and extend its TTW in a rat ischemic stroke model. These findings indicate that applications of nanoparticle DDS technology could be a hopeful approach to drug development for ischemic stroke therapy. In this review, we introduce our findings on ischemic stroke treatment using liposomal DDS and recent advances from other research groups.

Would antioxidant-loaded nanoparticles present an effective treatment for ischemic stroke?

Ischemic stroke is a leading cause of death and disability worldwide and is in urgent need of new treatment options. The only approved treatment for stroke restores blood flow to the brain, but much of the tissue damage occurs during the subsequent reperfusion. Antioxidant therapies that directly address ischemia-reperfusion injury have shown promise in preclinical results. In this review, we discuss that reformulating antioxidant therapies as nanomedicine can potentially overcome the barriers that have kept these therapies from succeeding in the clinic. We begin by reviewing the pathophysiology of ischemic stroke with a focus on the effects of reperfusion injury. Next, we review nanotherapeutic systems designed to treat the disease with a focus on those addressing reperfusion injury. Mechanisms of passive and active transport required to traverse a blood–brain barrier are discussed. Finally, we conclude by outlining design parameters for potentially successful nanomedicines as front-line therapeutics for ischemic stroke.

Research in the precaution of recombinant human erythropoietin to steroid-induced osteonecrosis of the rat femoral head

Objective

To elucidate the effects of recombinant human erythropoietin (rHuEPO) on steroid-induced osteonecrosis of the femoral head in rats.

Methods

Twenty-four adult Wistar rats were randomly divided into three groups of eight rats each. The rats in the positive control group were injected with dexamethasone at 1 mg/kg twice a week for 5 weeks. The rats in the negative control group were injected with sodium chloride alone. The rats in the experimental group were injected with dexamethasone at 1 mg/kg twice a week for 5 weeks and rHuEPO (500 u/d/kg) daily for 5 weeks. The femoral head on one side was examined by hematoxylin and eosin staining, and that on the other side was examined by CD31 staining of the capillaries.

Results

Hematoxylin and eosin staining in the positive control group showed that the bony trabeculae had become obviously narrow and sparse with discontinuity of the integrity. The integrity of the trabeculae was better in the experimental group than positive control group. The CD31 expression was lower in the positive control group than in the other two groups.

Conclusion

rHuEPO can effectively prevent osteocyte apoptosis, delaying or decreasing osteonecrosis of the femoral head.

Innovations in Liposomal DDS Technology and Its Application for the Treatment of Various Diseases

Liposomes have been widely used as drug carriers in the field of drug delivery systems (DDS), and they are thought to be ideal nano-capsules for targeting DDS after being injected into the bloodstream. In general, DDS drugs meet the needs of aged and super-aged societies, since the administration route of drugs can be changed, the medication frequency reduced, the adverse effects of drugs suppressed, and so on. In fact, a number of liposomal drugs have been launched and used worldwide including liposomal anticancer drugs, and these drugs have appeared on the market owing to various innovations in liposomal DDS technologies. The accumulation of long-circulating liposomes in cancer tissue is driven by the enhanced permeability and retention (EPR) effect. In this review, liposome-based targeting DDS for cancer therapy is briefly discussed. Since cancer angiogenic vessels are the ideal target of drug carriers after their injection and are critical for cancer growth, damaging of these neovessels has been an approach for eradicating cancer cells. Also, the usage of liposomal DDS for the treatment of ischemic stroke is possible, since we observed that PEGylated liposomes accumulate in the site of cerebral ischemia in transient middle cerebral artery occlusion (t-MCAO) model rats. Interestingly, liposomes carrying neuroprotectants partly suppress ischemia/reperfusion injury of these model rats, suggesting that the EPR effect also works in ischemic diseases by causing an increase in the permeability of the blood vessel endothelium. The potential of liposomal DDS against life-threatening diseases might thus be attractive for supporting long-lived societies.

Getting into the brain: liposome-based strategies for effective drug delivery across the blood-brain barrier

This review summarizes articles that have been reported in literature on liposome-based strategies for effective drug delivery across the blood–brain barrier. Due to their unique physicochemical characteristics, liposomes have been widely investigated for their application in drug delivery and in vivo bioimaging for the treatment and/or diagnosis of neurological diseases, such as Alzheimer’s, Parkinson’s, stroke, and glioma. Several strategies have been used to deliver drug and/or imaging agents to the brain. Covalent ligation of such macromolecules as peptides, antibodies, and RNA aptamers is an effective method for receptor-targeting liposomes, which allows their blood–brain barrier penetration and/or the delivery of their therapeutic molecule specifically to the disease site. Additionally, methods have been employed for the development of liposomes that can respond to external stimuli. It can be concluded that the development of liposomes for brain delivery is still in its infancy, although these systems have the potential to revolutionize the ways in which medicine is administered.

Neuroprotection against cerebral ischemia/reperfusion injury by intravenous administration of liposomal fasudil

Fasudil, a Rho-kinase inhibitor, is a promising neuroprotectant against ischemic stroke; however, its low bioavailability is an obstacle to be overcome. Our previous study revealed that the liposomal drug delivery system is a hopeful strategy to increase the therapeutic efficacy of neuroprotectants. In the present study, the usefulness of intravenously administered liposomal fasudil for cerebral ischemia/reperfusion (I/R) injury treatment was examined in transient middle cerebral artery occlusion (t-MCAO) rats. The results showed that PEGylated liposomes of approximately 100nm in diameter accumulated more extensively in the I/R region compared with those of over 200nm. Confocal images showed that fluorescence-labeled liposomal fasudil was widely distributed in the I/R region, and was not noticeably taken up by microglia, which are well-known resident macrophages in the brain, and neuronal cells. These data indicated that liposomal fasudil mainly exerted its pharmacological activity by releasing fasudil from the liposomes in the I/R region. Moreover, liposomal fasudil effectively suppressed neutrophil invasion and brain cell damage in the t-MCAO rats, resulting in amelioration of their motor function deficits. These findings demonstrated both the importance of particle size for neuroprotectant delivery and the effectiveness of liposomal fasudil for the treatment of cerebral I/R injury.

Charting a course for erythropoietin in traumatic brain injury

Traumatic brain injury (TBI) is a severe public health problem that impacts more than four million individuals in the United States alone and is increasing in incidence on a global scale. Importantly, TBI can result in acute as well as chronic impairments for the nervous system leaving individuals with chronic disability and in instances of severe trauma, death becomes the ultimate outcome. In light of the significant negative health consequences of TBI, multiple therapeutic strategies are under investigation, but those focusing upon the cytokine and growth factor erythropoietin (EPO) have generated a great degree of enthusiasm. EPO can control cell death pathways tied to apoptosis and autophagy as well oversees processes that affect cellular longevity and aging. In vitro studies and experimental animal models of TBI have shown that EPO can restore axonal integrity, promote cellular proliferation, reduce brain edema, and preserve cellular energy homeostasis and mitochondrial function. Clinical studies for neurodegenerative disorders that involve loss of cognition or developmental brain injury support a positive role for EPO to prevent or reduce injury in the nervous system. However, recent clinical trials with EPO and TBI have not produced such clear conclusions. Further clinical studies are warranted to address the potential efficacy of EPO during TBI, the concerns with the onset, extent, and duration of EPO therapeutic strategies, and to focus upon the specific downstream pathways controlled by EPO such as protein kinase B (Akt), mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), sirtuins, wingless pathways, and forkhead transcription factors for improved precision against the detrimental effects of TBI.

Regeneration in the nervous system with erythropoietin

Globally, greater than 30 million individuals are afflicted with disorders of the nervous system accompanied by tens of thousands of new cases annually with limited, if any, treatment options. Erythropoietin (EPO) offers an exciting and novel therapeutic strategy to address both acute and chronic neurodegenerative disorders. EPO governs a number of critical protective and regenerative mechanisms that can impact apoptotic and autophagic programmed cell death pathways through protein kinase B (Akt), sirtuins, mammalian forkhead transcription factors, and wingless signaling. Translation of the cytoprotective pathways of EPO into clinically effective treatments for some neurodegenerative disorders has been promising, but additional work is necessary. In particular, development of new treatments with erythropoiesis-stimulating agents such as EPO brings several important challenges that involve detrimental vascular outcomes and tumorigenesis. Future work that can effectively and safely harness the complexity of the signaling pathways of EPO will be vital for the fruitful treatment of disorders of the nervous system.

Treatment of stroke with liposomal neuroprotective agents under cerebral ischemia conditions

Since the proportion of patients given thrombolytic therapy with tissue plasminogen activator (t-PA) is very limited because of the narrow therapeutic window, the development of new therapies for ischemic stroke has been desired. We previously reported that liposomes injected intravenously accumulate in the ischemic region of the brain via disruption of the blood-brain barrier that occurs under cerebral ischemia. In the present study, we investigated the efficacy of a liposomal neuroprotective agent in middle cerebral artery occlusion (MCAO) rats to develop ischemic stroke therapy prior to the recovery of cerebral blood flow. For this purpose, PEGylated liposomes encapsulating FK506 (FK506-liposomes) were prepared and injected intravenously into MCAO rats after a 1-h occlusion. This treatment significantly suppressed the expansion of oxidative stress and brain cell damage. In addition, administration of FK506-liposomes before reperfusion significantly ameliorated motor function deficits of the rats caused by ischemia/reperfusion injury. These findings suggest that FK506-liposomes effectively exerted a neuroprotective effect during ischemic conditions, and that combination therapy with a liposomal neuroprotectant plus t-PA could be a promising therapeutic strategy for ischemic stroke.

Real-time trafficking of PEGylated liposomes in the rodent focal brain ischemia analyzed by positron emission tomography

Aliposomal drug delivery system was previously applied to ischemic brain model rats for the treatment of brain ischemia, and we observed that 100-nm-sized liposomes could extravasate and accumulate in the ischemic brain region even when cerebral blood flow was markedly reduced in permanent middle cerebral artery occlusion (p-MCAO) model rats. In the present study, we investigated the real-time cerebral distribution of polyethylene glycol (PEG)-modified liposomes (PEGliposomes) labeled with 1-[18F]fluoro-3,6-dioxatetracosane in p-MCAO rats by positron emission tomography (PET). [18F]-Labeled PEG-liposomes were intravenously injected into p-MCAO rats 1 h after the onset of occlusion, and then a PET scan was performed for 2 h. The PET scan showed that the signal intensity of [18F] gradually increased in the ischemic region despite the drastic reduction in cerebral perfusion, suggesting that PEG-liposomes had accumulated in and around the ischemic region. Therefore,drug delivery to the ischemic region by use of liposomes would be possible under ischemic conditions, and a liposomal drug delivery system could be a promising strategy for protecting the ischemic brain from damage before recovery from ischemia.

A gene responsible for prolyl-hydroxylation of moss-produced recombinant human erythropoietin

Recombinant production of pharmaceutical proteins is crucial, not only for personalized medicine. While most biopharmaceuticals are currently produced in mammalian cell culture, plant-made pharmaceuticals gain momentum. Post-translational modifications in plants are similar to those in humans, however, existing differences may affect quality, safety and efficacy of the products. A frequent modification in higher eukaryotes is prolyl-4-hydroxylase (P4H)-catalysed prolyl-hydroxylation. P4H sequence recognition sites on target proteins differ between humans and plants leading to non-human posttranslational modifications of recombinant human proteins produced in plants. The resulting hydroxyprolines display the anchor for plant-specific O-glycosylation, which bears immunogenic potential for patients. Here we describe the identification of a plant gene responsible for non-human prolyl-hydroxylation of human erythropoietin (hEPO) recombinantly produced in plant (moss) bioreactors. Targeted ablation of this gene abolished undesired prolyl-hydroxylation of hEPO and thus paves the way for plant-made pharmaceuticals humanized via glyco-engineering in moss bioreactors.