Recovery of Cognitive Dysfunction via Orally Administered Redox-Polymer Nanotherapeutics in SAMP8 Mice

Reactive oxygen species-scavenging nanomaterials for the prevention and treatment of age-related diseases

With increasing proportion of the elderly in the population, age-related diseases (ARD) lead to a considerable healthcare burden to society. Prevention and treatment of ARD can decrease the negative impact of aging and the burden of disease. The aging rate is closely associated with the production of high levels of reactive oxygen species (ROS). ROS-mediated oxidative stress in aging triggers aging-related changes through lipid peroxidation, protein oxidation, and DNA oxidation. Antioxidants can control autoxidation by scavenging free radicals or inhibiting their formation, thereby reducing oxidative stress. Benefiting from significant advances in nanotechnology, a large number of nanomaterials with ROS-scavenging capabilities have been developed. ROS-scavenging nanomaterials can be divided into two categories: nanomaterials as carriers for delivering ROS-scavenging drugs, and nanomaterials themselves with ROS-scavenging activity. This study summarizes the current advances in ROS-scavenging nanomaterials for prevention and treatment of ARD, highlights the potential mechanisms of the nanomaterials used and discusses the challenges and prospects for their applications.

Injectable biocompatible RAFT mediated nitroxide nanogels: A robust ROS-reduction antioxidant approach

This work introduces novel nitroxide-based nanogels (NGs) crafted through controlled RAFT (Reversible Addition Fragmentation chain Transfer) polymerization, showcasing over 85% improved shelf-life compared to native superoxide dismutase (SOD) enzymes. These 30-40 nm NGs hold great promise for injectable delivery, effectively reducing foam cell formation and displaying potent antioxidant behavior against various reactive oxygen species (ROS), revolutionizing antioxidant therapy. Featuring a meticulously designed core-shell structure via precise RAFT polymerization, these NGs mimic SOD enzymatic activity with nitroxide-based antioxidants, providing unprecedented defense against ROS. Combining methacrylated 2,2,6,6-Tetramethyl-4-piperidyl methacrylate (PMA) and Glycidyl methacrylate (GMA) monomers with precisely synthesized nitroxyl radicals results in exceptional properties. Validated through comprehensive analytical methods, these NGs exhibit remarkable stability, halting foam cell formation even at high concentrations, and demonstrate notable biocompatibility. Their ability to protect low density lipoprotein (LDL) from oxidation for up to a month positions them at the forefront of combating cardiovascular diseases, especially atherosclerosis. This study pioneers injectable antioxidant therapy, offering an innovative approach to cardiovascular ailments. Targeting narrow plaques signifies a promising intervention, reshaping cardiovascular disease treatments. It highlights the potential of advanced drug delivery in biomedicine, promising more effective cardiovascular disease treatments.

Design of Antioxidant Nanoparticle, which Selectively Locates and Scavenges Reactive Oxygen Species in the Gastrointestinal Tract, Increasing The Running Time of Mice

Excess reactive oxygen species (ROS) produced during strong or unfamiliar exercise cause exercise-induced gastrointestinal syndrome (EIGS), leading to poor health and decreased exercise performance. The application of conventional antioxidants can neither ameliorate EIGS nor improve exercise performance because of their rapid elimination and severe side effects on the mitochondria. Hence, a self-assembling nanoparticle-type antioxidant (RNPO ) that is selectively located in the gastrointestinal (GI) tract for an extended time after oral administration is developed. Interestingly, orally administered RNPO significantly enhances the running time until exhaustion in mice with increasing dosage, whereas conventional antioxidants (TEMPOL) tends to reduce the running time with increasing dosage. The running (control) and TEMPOL groups show severe damage in the GI tract and increased plasma lipopolysaccharide (LPS) levels after 80 min of running, resulting in fewer red blood cells (RBCs) and severe damage to the skeletal muscles and liver. However, the RNPO group is protected against GI tract damage and elevation of plasma LPS levels, similar to the nonrunning (sedentary) group, which prevents damage to the whole body, unlike in the control and TEMPOL groups. Based on these results, it is concluded that continuous scavenging of excessive intestinal ROS protects against gut damage and further improves exercise performance.

Nanoparticles: Taking a Unique Position in Medicine

The human nature of curiosity, wonder, and ingenuity date back to the age of humankind. In parallel with our history of civilization, interest in scientific approaches to unravel mechanisms underlying natural phenomena has been developing. Recent years have witnessed unprecedented growth in research in the area of pharmaceuticals and medicine. The optimism that nanotechnology (NT) applied to medicine and drugs is taking serious steps to bring about significant advances in diagnosing, treating, and preventing disease-a shift from fantasy to reality. The growing interest in the future medical applications of NT leads to the emergence of a new field for nanomaterials (NMs) and biomedicine. In recent years, NMs have emerged as essential game players in modern medicine, with clinical applications ranging from contrast agents in imaging to carriers for drug and gene delivery into tumors. Indeed, there are instances where nanoparticles (NPs) enable analyses and therapies that cannot be performed otherwise. However, NPs also bring unique environmental and societal challenges, particularly concerning toxicity. Thus, clinical applications of NPs should be revisited, and a deep understanding of the effects of NPs from the pathophysiologic basis of a disease may bring more sophisticated diagnostic opportunities and yield more effective therapies and preventive features. Correspondingly, this review highlights the significant contributions of NPs to modern medicine and drug delivery systems. This study also attempted to glimpse the future impact of NT in medicine and pharmaceuticals.

Self-Assembling Antioxidants for Ischemia-Reperfusion Injuries

Significance: Ischemia-reperfusion (IR) injury is a major component of severe damage in vascular occlusion during stroke, myocardial infarction, surgery, and organ transplantation, and is exacerbated by the excessive generation of reactive oxygen species (ROS), which occurs particularly during reperfusion. With the aging of the population, IR injury is becoming a serious problem in various organs, such as the kidney, brain, and heart, as well as in the mesenteric capillaries. Recent Advances: To prevent reperfusion injuries, natural and synthetic low-molecular-weight (LMW) antioxidants have been well studied. Critical Issues: However, these LMW antioxidants have various problems, including adverse effects due to excessive cellular uptake and their rapid clearance by the kidney, and cannot fully exert their potent antioxidant capacity in vivo. Future Directions: To overcome these problems, we designed and developed redox polymers with antioxidants covalently conjugated with them. These polymers self-assemble into nanoparticles in aqueous media, referred to as redox nanoparticles (RNPs). RNPs suppress their uptake into normal cells, accumulate at inflammation sites, and effectively scavenge ROS in damaged tissues. We had developed two types of RNPs: RNP^N, which disintegrates in response to acidic pH; and RNP^O, which does not collapse, regardless of the environmental pH. Utilizing the pH-sensitive and -insensitive characteristics of RNP^N and RNP^O, respectively, RNPs were found to exhibit remarkable therapeutic effects on various oxidative stress disorders, including IR injuries. Thus, RNPs are promising nanomedicines for use as next-generation antioxidants. This review summarizes the therapeutic impacts of RNPs in the treatment of kidney, cerebral, myocardial, and intestinal IR injuries. Antioxid. Redox Signal. 36, 70-80.

Nanozymes Regulate Redox Homeostasis in ROS-Related Inflammation

Reactive oxygen species (ROS), in moderate amounts, play an essential role in regulating different physiological functions in organisms. However, increased amounts of ROS may cause oxidative stress and damage to biomolecules, leading to a variety of diseases including inflammation and even cancer. Therefore, ROS scavenging reagents are needed to maintain healthy levels of ROS. With considerable advances in nanotechnology, nanozymes possess SOD or CAT-like activities with outstanding free radical scavenging activity, facile synthesis conditions, and excellent biocompatibility. Based on these extraordinary properties, nanozymes has been used to modulate the redox homeostasis and relieve the ROS-related injury. This has led to the emergence of nanozyme-based therapies. In the current review, we presented recently developed applications of nanozymes to treat ROS-dependent disorders with an emphasis on inflammatory and brain diseases.

An Antioxidant Nanoparticle Enhances Exercise Performance in Rat High-intensity Running Models

Although the adverse effects of excessively generated reactive oxygen species (ROS) on the body during aerobic exercise have been debated, there are few reports on the remarkable effects of the application of conventional antioxidants on exercise performance. The conventional antioxidants could not enhance exercise performance due to their rapid excretion from the body and serious adverse effects on the cellular respiratory system. In this study, impact of the original antioxidant self-assembling nanoparticle, redox-active nanoparticle (RNP), is investigated on the exercise performance of rats during running experiments. With an increase in the dose of the administered RNP, the all-out time of the rat running extends in a dose-dependent manner. In contrast, with an increase in the dose of the low-molecular-weight (LMW) antioxidant, the all-out running time of the rats decreases. The control group and LMW antioxidant treated group decrease in the number of red blood cells (RBCs) and increase oxidative stress after running. However, the RNP group maintains a similar RBC level and oxidative stress as that of the sedentary group. The results suggest that RNP, which shows long-blood circulation without disturbance of mitohormesis, effectively removes ROS from the bloodstream to suppresses RBC oxidative stress and damage, thus improving exercise performance.

Redox-Responsive Nanobiomaterials-Based Therapeutics for Neurodegenerative Diseases

Redox regulation has recently been proposed as a critical intracellular mechanism affecting cell survival, proliferation, and differentiation. Redox homeostasis has also been implicated in a variety of degenerative neurological disorders such as Parkinson's and Alzheimer's disease. In fact, it is hypothesized that markers of oxidative stress precede pathologic lesions in Alzheimer's disease and other neurodegenerative diseases. Several therapeutic approaches have been suggested so far to improve the endogenous defense against oxidative stress and its harmful effects. Among such approaches, the use of artificial antioxidant systems has gained increased popularity as an effective strategy. Nanoscale drug delivery systems loaded with enzymes, bioinspired catalytic nanoparticles and other nanomaterials have emerged as promising candidates. The development of degradable hydrogels scaffolds with antioxidant effects could also enable scientists to positively influence cell fate. This current review summarizes nanobiomaterial-based approaches for redox regulation and their potential applications as central nervous system neurodegenerative disease treatments.

Nitroxide Radical-Containing Redox Nanoparticles Protect Neuroblastoma SH-SY5Y Cells against 6-Hydroxydopamine Toxicity

Parkinson's disease (PD) patients can benefit from antioxidant supplementation, and new efficient antioxidants are needed. The aim of this study was to evaluate the protective effect of selected nitroxide-containing redox nanoparticles (NRNPs) in a cellular model of PD. Antioxidant properties of NRNPs were studied in cell-free systems by protection of dihydrorhodamine 123 against oxidation by 3-morpholino-sydnonimine and protection of fluorescein against bleaching by 2,2-azobis(2-amidinopropane) hydrochloride and sodium hypochlorite. Model blood-brain barrier penetration was studied using hCMEC/D3 cells. Human neuroblastoma SH-SY5Y cells, exposed to 6-hydroxydopamine (6-OHDA), were used as an in vitro model of PD. Cells were preexposed to NRNPs or free nitroxides (TEMPO or 4-amino-TEMPO) for 2 h and treated with 6-OHDA for 1 h and 24 h. The reactive oxygen species (ROS) level was estimated with dihydroethidine 123 and Fluorimetric Mitochondrial Superoxide Activity Assay Kit. Glutathione level (GSH) was measured with ortho-phtalaldehyde, ATP by luminometry, changes in mitochondrial membrane potential with JC-1, and mitochondrial mass with 10-Nonyl-Acridine Orange. NRNP1, TEMPO, and 4-amino-TEMPO (25-150 μM) protected SH-SY5Y cells from 6-OHDA-induced viability loss; the protection was much higher for NRNP1 than for free nitroxides. NRNP1 were better antioxidants in vitro and permeated better the model BBB than free nitroxides. Exposure to 6-OHDA decreased the GSH level after 1 h and increased it considerably after 24 h (apparently a compensatory overresponse); NRNPs and free nitroxides prevented this increase. NRNP1 and free nitroxides prevented the decrease in ATP level after 1 h and increased it after 24 h. 6-OHDA increased the intracellular ROS level and mitochondrial superoxide level. Studied antioxidants mostly decreased ROS and superoxide levels. 6-OHDA decreased the mitochondrial potential and mitochondrial mass; both effects were prevented by NRNP1 and nitroxides. These results suggest that the mitochondria are the main site of 6-OHDA-induced cellular damage and demonstrate a protective effect of NRNP1 in a cellular model of PD.

Nanomaterials and Aging

As the proportion of the elderly population increases, more and more people suffer from aging-related diseases. Even if aging is inevitable, prolonging the time of healthy aging, delaying the progression of aging-related diseases, and the incidence of morbidity can greatly alleviate the pressure on individuals and society. Current research and exploration in the field of materials related to aging are expanding tremendously. Here, we present a summary of recent research in the field of nanomaterials relevant to aging. Some nanomaterials, such as silica nanomaterials (NMs) and carbon nanotubes, cause damage to the cells similar to aging processes. Other nanomaterials such as fullerenes and metalbased nanomaterials can protect the body from endogenous and exogenous harmful substances such as ROS by virtue of their excellent reducing properties. Another new type of nucleic acid nanomaterial, tetrahedral framework nucleic acids, works effectively against cell damage. This material selectively clears existing senescent cells in the tissue and thus prevents the development of the chronic inflammatory environment caused by senescent cells secreting senescence-associated secretory phenotype to the surroundings. We believe that nanomaterials have tremendous potential to advance the understanding and treatment of aging-related disorders, and today's research only represents the beginning stages.

Nanodelivery systems and stabilized solid-drug nanoparticles for orally administered medicine: current landscape

The use of nanoparticles as a means of targeted delivery of therapeutics and imaging agents could greatly enhance the transport of biologically active contents to specific target tissues, while avoiding or reducing potentially undesired side effects. Generally speaking, the oral route of administration is associated with good patient compliance, as it is convenient, economical, noninvasive, and does not require special training. Here, we review the progress of the utilization of nanodelivery-system carriers or stabilized solid-drug nanoparticles following oral administration, with particular attention on toxicological data. Mechanisms of cytotoxicity are discussed and the problem of extrapolating knowledge to human scenarios highlighted. Additionally, issues associated with administration of drugs via the oral route are underlined, while strategies utilized to overcome these are highlighted. This review aims to offer a balanced overview of strategies currently being used in the application of nanosize constructs for oral medical applications.

Redox nanoparticles: synthesis, properties and perspectives of use for treatment of neurodegenerative diseases

Oxidative stress (OS) and nitrative stress (NS) accompany many diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). Antioxidants have been proposed to counteract OS/NS in these diseases. Nevertheless, the effects of antioxidants are limited and new, more efficient antioxidants are searched for. Redox-active nanoparticles (RNPs), containing antioxidants create a new therapeutical perspective. This review examines the recent literature describing synthesis and potential applications of cerium oxide RNPs, boron cluster-containing and silica containing RNPs, Gd₃N_@C₈₀ encapsulated RNPs, and concentrates on nitroxide-containing RNPs. Nitroxides are promising antioxidants, preventing inter alia glycation and nitration, but their application poses several problems. It can be expected that application of RNPs containing covalently bound nitroxides, showing low toxicity and able to penetrate the blood-brain barrier will be more efficient in the treatment of neurodegenerative disease, in particular AD and PD basing on their effects in cellular and animal models of neurodegenerative diseases.

Nanoparticles in Medicine: A Focus on Vascular Oxidative Stress

Nanotechnology has had a significant impact on medicine in recent years, its application being referred to as nanomedicine. Nanoparticles have certain properties with biomedical applications; however, in some situations, they have demonstrated cell toxicity, which has caused concern surrounding their clinical use. In this review, we focus on two aspects: first, we summarize the types of nanoparticles according to their chemical composition and the general characteristics of their use in medicine, and second, we review the applications of nanoparticles in vascular alteration, especially in endothelial dysfunction related to oxidative stress. This condition can lead to a reduction in nitric oxide (NO) bioavailability, consequently affecting vascular tone regulation and endothelial dysfunction, which is the first phase in the development of cardiovascular diseases. Therefore, nanoparticles with antioxidant properties may improve vascular dysfunction associated with hypertension, diabetes mellitus, or atherosclerosis.

[Design of New Cancer Nanotherapeutics Which Controls Active Gaseous Molecules in Vivo]

　Reactive oxygen species (ROS) are known to play a variety of roles in many important events in vivo. However, the overproduction of ROS causes serious adverse effects to living beings. Numerous drugs have been developed and applied to reduce overproduced ROS, but these have failed to be clinically approved. Since most of these antioxidants are low molecular weight (LMW) compounds, they not only eliminate ROS related to diseases, but also destroy the essential redox reactions necessary for basic energy production in living bodies. In the mitochondria of normal cells, ATP production by electron transport chain is carried out, and a large amount of ROS is thus generated; however, LMW antioxidants also nonspecifically enter normal cells and affect essential oxidation. To improve selective antioxidant properties without damage to these normal redox reactions, we designed new polymer antioxidants. These polymers have self-assembling properties and form nanoparticles (RNPs) in which nitroxide radicals covalently attach as a side chain of the hydrophobic segment in the amphiphilic block copolymers, which are then compartmentalized into the solid core of the nanoparticles. Unlike LMW antioxidants, RNPs have extremely poor in vivo toxicity, as they are less likely to be taken up by healthy cells. Since one of RNPs, RNP^N has pH-sensitive disintegration properties, it disintegrates at pH lower than 7.0 such as solid tumors and inflammation. It can therefore be used in pH responsive bioimaging and therapy. We have used RNPs experimentally in the treatment of several diseases and confirmed their effectiveness.

Antioxidative biointerface: biocompatible materials scavenging reactive oxygen species

Oxidative stress caused by reactive oxygen species (ROS) occurs as events in which living tissues contact certain materials. These events include cell cultures and implantation of materials. Because of the high reactivity of ROS, they damage cells by oxidizing DNA, lipids, and proteins. Conversely, ROS also act as signaling molecules regulating cellular morphology. In particular, mitochondrial ROS are involved in the regulation of cellular physiology, including differentiation, autophagy, metabolic adaptation, apoptosis, and immunity. The balance between generation and elimination of ROS is essential for signaling pathways and proper cell function, and redox imbalance leads to cellular dysfunction and disturbs cellular homeostasis. To reduce oxidative stress, versatile antioxidants, including natural compounds, have been used; however, their poor bioavailability and pro-oxidant effects have limited the versatility of these antioxidants. Recent developments of antioxidative biointerfaces may represent a potent solution to this issue. Designed biointerfaces composed of polymer antioxidants eliminate excessive ROS at the interface between living tissues and materials, and do not disturb regulated redox balance inside cells, thus eliminating unexpected cell responses, such as inflammation and dysfunction.

Nitroxide radical polymers – a versatile material class for high-tech applications

A comprehensive summary of synthetic strategies for the preparation of nitroxide radical polymer materials and a state-of-the-art perspective on their latest and most exciting applications.

Newly Designed Silica-Containing Redox Nanoparticles for Oral Delivery of Novel TOP2 Catalytic Inhibitor for Treating Colon Cancer

Although oral drug delivery is the most common route of drug administration, the conventional polymeric nanocarriers exhibit a low drug loading capacity and low stability in the gastrointestinal (GI) environments. In this study, a newly designed silica-containing redox nanoparticle (siRNP) with reactive oxygen species (ROS) scavenging capacity is developed as an ideal oral nanocarrier for a novel hydrophobic anticancer compound BNS-22 to treat colitis-associated colon cancer in vivo. Crosslinking of silica moieties significantly enhances the stability under acidic conditions and improves BNS-22 loading capacity of siRNP compared to the conventional redox nanoparticle. After oral administration to mice, BNS-22-loaded siRNP (BNS-22@siRNP) remarkably improves bioavailability and colonic tumor distribution of BNS-22. As the result, BNS-22@siRNP significantly inhibits the tumor progression in colitis-associated colon cancer mice compared to other control treatments. It is noteworthy that no systemic absorption of siRNP carrier is observed after oral administration. Interestingly, orally administered BNS-22@siRNP significantly suppresses the adverse effects of BNS-22 owing to its ROS scavenging capacity, and no other noticeable toxicities are observed in mice treated with BNS-22@siRNP although siRNP is localized in the GI tract. Our results indicate that siRNP is a promising oral drug nanocarrier for cancer therapy.

Apoptotic Cell Membrane-Inspired Polymer for Immunosuppression

Apoptotic cell death serves important roles in homeostasis by eliminating dangerous, damaged, or unnecessary cells without causing an inflammatory response by externalizing phosphatidylserine to the outer leaflet in the phospholipid bilayer. In this study, we newly designed apoptotic cell membrane-inspired monomer and polymer which have the phosphoryl serine group as the anti-inflammatory functional moiety and demonstrate here for the first time that administration of an apoptotic cell membrane-inspired phosphorylserine polymer can protect murine macrophages (RAW 264.7) from lipopolysaccharide-induced inflammation. Interestingly, statistical copolymers with phosphorylcholine monomer that mimicked more precisely the apoptotic cell membrane result in more effective suppression of macrophage activation. This study provides new insights into the rational design of effective polymeric materials for anti-inflammatory therapies.

Development of a local anesthetic lidocaine-loaded redox-active injectable gel for postoperative pain management

Although local anesthesia is commonly applied for pain relief, there are several issues such as its short duration of action and low effectiveness at the areas of inflammation due to the acidic pH. The presence of excessive amount of reactive oxygen species (ROS) is known to induce inflammation and aggravate pain. To resolve these issues, we developed a redox-active injectable gel (RIG) with ROS-scavenging activity. RIG was prepared by mixing polyamine-b-poly(ethylene glycol)-b-polyamine with nitroxide radical moieties as side chains on the polyamine segments (PMNT-b-PEG-b-PMNT) with a polyanion, which formed a flower-type micelle via electrostatic complexation. Lidocaine could be stably incorporated in its core. When the temperature of the solution was increased to 37°C, the PIC-type flower micelle transformed to gel. The continuous release of lidocaine from the gel was observed for more than three days, without remarkable initial burst, which is probably owing to the stable entrapment of lidocaine in the PIC core of the gel. We evaluated the analgesic effect of RIG in carrageenan-induced arthritis mouse model. Results showed that lidocaine-loaded RIG has stronger and longer analgesic effect when administered in inflamed areas. In contrast, while the use of non-complexed lidocaine did not show analgesic effect one day after its administration. Note that no effect was observed when PIC-type flower micelle without ROS-scavenging ability was used. These findings suggest that local anesthetic-loaded RIG can effectively reduce the number of injection times and limit the side effects associated with the use of anti-inflammatory drugs for postoperative pain management.

STATEMENT OF SIGNIFICANCE

1. We have been working on nanomaterials, which effectively eliminate ROS, avoiding dysfunction of mitochondria in healthy cells. 2. We designed redox injectable gel using polyion complexed flower type micelle, which can eliminates ROS locally. 3. We could prepare local anesthesia-loaded redox injectable gel (lido@RIG). 4. Drug release could be extended by local administration of lido@RIG. 5. Deprotonation of lidocaine improved anesthetic effect because ROS were eliminated locally by RIG. 6. Local inflammation could be also suppressed by lido@RIG.

Chronic treatment with a smart antioxidative nanoparticle for inhibition of amyloid plaque propagation in Tg2576 mouse model of Alzheimer's disease

The present study aimed to assess whether our newly developed redox nanoparticle (RNP^N) that has antioxidant potential decreases Aβ levels or prevents Aβ aggregation associated with oxidative stress. The transgenic Tg2576 Alzheimer’s disease (AD) mice were used to investigate the effect of chronic ad libitum drinking of RNP^N solution for 6 months, including memory and learning functions, antioxidant activity, and amyloid plaque aggregation. The results showed that RNP^N-treated mice had significantly attenuated cognitive deficits of both spatial and non-spatial memories, reduced oxidative stress of lipid peroxide, and DNA oxidation. RNP^N treatment increased the percent inhibition of superoxide anion and glutathione peroxidase activity, neuronal densities in the cortex and hippocampus, decreased Aβ(1-40), Aβ(1-42) and gamma (γ)-secretase levels, and reduced Aβ plaque observed using immunohistochemistry analysis and thioflavin S staining. Our results suggest that RNP^N may be a promising candidate for AD therapy because of its antioxidant properties and reduction in Aβ aggregation, thereby suppressing its adverse side effect.

Systems-level thinking for nanoparticle-mediated therapeutic delivery to neurological diseases

Neurological diseases account for 13% of the global burden of disease. As a result, treating these diseases costs $750 billion a year. Nanotechnology, which consists of small (~1-100 nm) but highly tailorable platforms, can provide significant opportunities for improving therapeutic delivery to the brain. Nanoparticles can increase drug solubility, overcome the blood-brain and brain penetration barriers, and provide timed release of a drug at a site of interest. Many researchers have successfully used nanotechnology to overcome individual barriers to therapeutic delivery to the brain, yet no platform has translated into a standard of care for any neurological disease. The challenge in translating nanotechnology platforms into clinical use for patients with neurological disease necessitates a new approach to: (1) collect information from the fields associated with understanding and treating brain diseases and (2) apply that information using scalable technologies in a clinically-relevant way. This approach requires systems-level thinking to integrate an understanding of biological barriers to therapeutic intervention in the brain with the engineering of nanoparticle material properties to overcome those barriers. To demonstrate how a systems perspective can tackle the challenge of treating neurological diseases using nanotechnology, this review will first present physiological barriers to drug delivery in the brain and common neurological disease hallmarks that influence these barriers. We will then analyze the design of nanotechnology platforms in preclinical in vivo efficacy studies for treatment of neurological disease, and map concepts for the interaction of nanoparticle physicochemical properties and pathophysiological hallmarks in the brain. WIREs Nanomed Nanobiotechnol 2017, 9:e1422. doi: 10.1002/wnan.1422 For further resources related to this article, please visit the WIREs website.

Redox Nanoparticle Therapeutics for Acetaminophen-Induced Hepatotoxicity in Mice

The purpose of this study was to evaluate the hepatoprotective effect of an antioxidative nanoparticle (RNP(N)) recently developed against APAP-induced hepatotoxicity in mice. The effects of oral administration of RNP(N) to APAP-treated mice were assessed for various biochemical liver function parameters: alanine transaminase (ALT) activity, aspartate transaminase (AST) activity, alkaline phosphatase (ALP) activity, prothrombin time, and serum albumin (ALB) level. The treatment effects were assessed in terms of free radical parameters: malondialdehyde (MDA) accumulation, glutathione peroxidase (GPx) activity, % inhibition of superoxide anion (O2 (-∙)), and histopathological examination. The N-acetylcysteine (NAC)-treated group exhibited an enhanced prothrombin time relative to the control group, while RNP(N) did not prolong prothrombin time. The RNP(N)-treated animals exhibited lower levels of ALT, AST, and ALP, while increased ALB levels were measured in these animals compared to those in the other groups. The RNP(N)-treated animals furthermore exhibited improved MDA levels, GPx activity, and % inhibition of O2 (-∙), which relate to oxidative damage. Histological staining of liver tissues from RNP(N)-treated animals did not reveal any microscopic changes relative to the other groups. The findings of this study suggest that RNP(N) possesses effective hepatoprotective properties and does not exhibit the notable adverse effects associated with NAC treatment.

Nanomedicine in the ROS-mediated pathophysiology: Applications and clinical advances

Reactive oxygen species (ROS) are important in regulating normal cell physiological functions, but when produced in excess lead to the augmented pathogenesis of various diseases. Among these, ischemia reperfusion injury, Alzheimer's disease and rheumatoid arthritis are particularly important. Since ROS can be counteracted by a variety of antioxidants, natural and synthetic antioxidants have been developed. However, due to the ubiquitous production of ROS in living systems, poor in vivo efficiency of these agents and lack of target specificity, the current clinical modalities to treat oxidative stress damage are limited. Advances in the developing field of nanomedicine have yielded nanoparticles that can prolong antioxidant activity, and target specificity of these agents. This article reviews recent advances in antioxidant nanoparticles and their applications to manage oxidative stress-mediated diseases.

FROM THE CLINICAL EDITOR

Production of reactive oxygen species (ROS) is a purely physiological process in many disease conditions. However, excessive and uncontrolled production will lead to oxidative stress and further tissue damage. Advances in nanomedicine have provided many novel strategies to try to combat and counteract ROS. In this review article, the authors comprehensively highlighted the current status and future developments in using nanotechnology for providing novel therapeutic options in this field.

Redox nanoparticles as a novel treatment approach for inflammation and fibrosis associated with nonalcoholic steatohepatitis

AIM

Oxidative stress (OS) is largely thought to be a central mechanism responsible for liver damage, inflammation and fibrosis in nonalcoholic steatohepatitis (NASH). Our aim was to investigate whether suppression of OS in the liver via redox nanoparticles (RNPs) reduces liver damage in a mouse model of NASH.

MATERIALS & METHODS

RNPs were prepared by self-assembly of redox polymers possessing antioxidant nitroxide radicals and were orally administered by daily gavage for 4 weeks.

RESULTS

The redox polymer was delivered to the liver after disintegration of nanoparticle in the stomach. RNP treatment in NASH mice via gavage led to a reduction of liver OS, improvement of fibrosis, and significant reduction of inflammation.

CONCLUSION

These findings uncover RNP as a novel potential NASH therapy.