Nanoparticles responsive to the inflammatory microenvironment for targeted treatment of arterial restenosis

Nanoparticles as Drug Delivery Systems for the Targeted Treatment of Atherosclerosis

Atherosclerosis continues to be a leading cause of morbidity and mortality globally. The precise evaluation of the extent of an atherosclerotic plaque is essential for forecasting its likelihood of causing health concerns and tracking treatment outcomes. When compared to conventional methods used, nanoparticles offer clear benefits and excellent development opportunities for the detection and characterisation of susceptible atherosclerotic plaques. In this review, we analyse the recent advancements of nanoparticles as theranostics in the management of atherosclerosis, with an emphasis on applications in drug delivery. Furthermore, the main issues that must be resolved in order to advance clinical utility and future developments of NP research are discussed. It is anticipated that medical NPs will develop into complex and advanced next-generation nanobotics that can carry out a variety of functions in the bloodstream.

Vascular stent with immobilized anti-inflammatory chemerin 15 peptides mitigates neointimal hyperplasia and accelerates vascular healing

Endovascular stenting is a safer alternative to open surgery for use in treating cerebral arterial stenosis and significantly reduces the recurrence of ischemic stroke, but the widely used bare-metal stents (BMSs) often result in in-stent restenosis (ISR). Although evidence suggests that drug-eluting stents are superior to BMSs in the short term, their long-term performances remain unknown. Herein, we propose a potential vascular stent modified by immobilizing clickable chemerin 15 (C15) peptides on the stent surface to suppress coagulation and restenosis. Various characterization techniques and an animal model were used to evaluate the surface properties of the modified stents and their effects on endothelial injury, platelet adhesion, and inflammation. The C15-immobilized stent could prevent restenosis by minimizing endothelial injury, promoting physiological healing, restraining the platelet-leukocyte-related inflammatory response, and inhibiting vascular smooth muscle cell proliferation and migration. Furthermore, in vivo studies demonstrated that the C15-immobilized stent mitigated inflammation, suppressed neointimal hyperplasia, and accelerated endothelial restoration. The use of surface-modified, anti-inflammatory, endothelium-friendly stents may be of benefit to patients with arterial stenosis. STATEMENT OF SIGNIFICANCE: Endovascular stenting is increasingly used for cerebral arterial stenosis treatment, aiming to prevent and treat ischemic stroke. But an important accompanying complication is in-stent restenosis (ISR). Persistent inflammation has been established as a hallmark of ISR and anti-inflammation strategies in stent modification proved effective. Chemerin 15, an inflammatory resolution mediator with 15-aa peptide, was active at picomolar through cell surface receptor, no need to permeate cell membrane and involved in resolution of inflammation by inhibiting inflammatory cells adhesion, modulating macrophage polarization into protective phenotype, and reducing inflammatory factors release. The implications of this study are that C15 immobilized stent favors inflammation resolution and rapid re-endothelialization, and exhibits an inhibitory role of restenosis. As such, it helps the decreased incidence of ISR.

Navigating the landscape: Prospects and hurdles in targeting vascular smooth muscle cells for atherosclerosis diagnosis and therapy

Vascular smooth muscle cells (VSMCs) have emerged as pivotal contributors throughout all phases of atherosclerotic plaque development, effectively dispelling prior underestimations of their prevalence and significance. Recent lineage tracing studies have unveiled the clonal nature and remarkable adaptability inherent to VSMCs, thereby illuminating their intricate and multifaceted roles in the context of atherosclerosis. This comprehensive review provides an in-depth exploration of the intricate mechanisms and distinctive characteristics that define VSMCs across various physiological processes, firmly underscoring their paramount importance in shaping the course of atherosclerosis. Furthermore, this review offers a thorough examination of the significant strides made over the past two decades in advancing imaging techniques and therapeutic strategies with a precise focus on targeting VSMCs within atherosclerotic plaques, notably spotlighting meticulously engineered nanoparticles as a promising avenue. We envision the potential of VSMC-targeted nanoparticles, thoughtfully loaded with medications or combination therapies, to effectively mitigate pro-atherogenic VSMC processes. These advancements are poised to contribute significantly to the pivotal objective of modulating VSMC phenotypes and enhancing plaque stability. Moreover, our paper also delves into recent breakthroughs in VSMC-targeted imaging technologies, showcasing their remarkable precision in locating microcalcifications, dynamically monitoring plaque fibrous cap integrity, and assessing the therapeutic efficacy of medical interventions. Lastly, we conscientiously explore the opportunities and challenges inherent in this innovative approach, providing a holistic perspective on the potential of VSMC-targeted strategies in the evolving landscape of atherosclerosis research and treatment.

Exoskeleton Partial-Coated Stem Cells for Infarcted Myocardium Restoring

The integration of abiotic materials with live cells has emerged as an exciting strategy for the control of cellular functions. Exoskeletons consisting ofmetal-organic frameworks are generated to produce partial-coated bone marrow stem cells (BMSCs) to overcome low cell survival leading to disappointing effects for cell-based cardiac therapy. Partially coated exoskeletons can promote the survival of suspended BMSCs by integrating the support of exoskeletons and unimpaired cellular properties. In addition, partial exoskeletons exhibit protective effects against detrimental environmental conditions, including reactive oxygen species, pH changes, and osmotic pressure. The partial-coated cells exhibit increased intercellular adhesion forces to aggregate and adhere, promoting cell survival and preventing cell escape during cell therapy. The exoskeletons interact with cell surface receptors integrin α5β1, leading to augmented biological functions with profitable gene expression alteration, such as Vegfa, Cxcl12, and Adm. The partial-coated BMSCs display enhanced cell retention in infarcted myocardium through non-invasive intravenous injections. The repair of myocardial infarction has been achieved with improved cardiac function, myocardial angiogenesis, proliferation, and inhibition of cell apoptosis. This discovery advances the elucidation of potential molecular and cellular mechanisms for cell-exoskeleton interactions and benefits the rational design and manufacture of next-generation nanobiohybrids.

Inflammation-responsive drug delivery nanosystems for treatment of bacterial-induced sepsis

Sepsis, a complication of dysregulated host immune systemic response to an infection, is life threatening and causes multiple organ injuries. Sepsis is recognized by WHO as a big contributor to global morbidity and mortality. The heterogeneity in sepsis pathophysiology, antimicrobial resistance threat, the slowdown in the development of antimicrobials, and limitations of conventional dosage forms jeopardize the treatment of sepsis. Drug delivery nanosystems are promising tools to overcome some of these challenges. Among the drug delivery nanosystems, inflammation-responsive nanosystems have attracted considerable interest in sepsis treatment due to their ability to respond to specific stimuli in the sepsis microenvironment to release their payload in a precise, targeted, controlled, and rapid manner compared to non-responsive nanosystems. These nanosystems posit superior therapeutic potential to enhance sepsis treatment. This review critically evaluates the recent advances in the design of drug delivery nanosystems that are inflammation responsive and their potential in enhancing sepsis treatment. The sepsis microenvironment's unique features, such as acidic pH, upregulated receptors, overexpressed enzymes, and enhanced oxidative stress, that form the basis for their design have been adequately discussed. These inflammation-responsive nanosystems have been organized into five classes namely: Receptor-targeted nanosystems, pH-responsive nanosystems, redox-responsive nanosystems, enzyme-responsive nanosystems, and multi-responsive nanosystems. Studies under each class have been thematically grouped and discussed with an emphasis on the polymers used in their design, nanocarriers, key characterization, loaded actives, and key findings on drug release and therapeutic efficacy. Further, this information is concisely summarized into tables and supplemented by inserted figures. Additionally, this review adeptly points out the strengths and limitations of the studies and identifies research avenues that need to be explored. Finally, the challenges and future perspectives on these nanosystems have been thoughtfully highlighted.

Genome editing mRNA nanotherapies inhibit cervical cancer progression and regulate the immunosuppressive microenvironment for adoptive T-cell therapy

CRISPR/Cas9-based genome editing is promising for therapy of cervical cancer by precisely targeting human papillomavirus (HPV). To develop CRISPR/Cas9-based genome editing nanotherapies, a pH-responsive hybrid nonviral nanovector was constructed for co-delivering Cas9 mRNA and guide RNAs (gRNAs) targeting E6 or E7 oncogenes. The pH-responsive nanovector was fabricated using an acetalated cyclic oligosaccharide (ACD), in combination with low molecular weight polyethyleneimine. Thus obtained hybrid ACD nanoparticles (defined as ACD NP) showed efficient loading for both Cas9 mRNA and E6 or E7 gRNA, giving rise to two pH-responsive genome editing nanotherapies E6/ACD NP and E7/ACD NP, respectively. Cellularly, ACD NP exhibited high transfection but low cytotoxicity in HeLa cervical carcinoma cells. Also, efficient genome editing of target genes was achieved in HeLa cells, with minimal off-target effects. In mice bearing HeLa xenografts, treatment with E6/ACD NP or E7/ACD NP afforded effective editing of target oncogenes and considerable antitumor activities. More importantly, treatment with E6/ACD NP or E7/ACD NP notably promoted CD8+ T cell survival by reversing the immunosuppressive microenvironment, thereby leading to synergistic antitumor effects by combination therapy using the gene editing nanotherapies and adoptive T-cell transfer. Consequently, our pH-responsive genome editing nanotherapies deserve further development for the treatment of HPV-associated cervical cancer, and they can also serve as promising nanotherapies to improve efficacies of other immune therapies against different advanced cancers by regulating the immunosuppressive tumor microenvironment.

Immunomodulation in age-related disorders and nanotechnology interventions

Recently, the aging population has increased exponentially around the globe bringing more challenges to improve quality of life in those populations while reducing the economic burden on healthcare systems. Aging is associated with changes in the immune system culminating in detrimental effects such as immune dysfunction, immunosenescence, and chronic inflammation. Age-related decline of immune functions is associated with various pathologies including cardiovascular, autoimmune, neurodegenerative, and infectious diseases to name a few. Conventional treatment addresses the onset of age-related diseases by early detection of risk factors, administration of vaccines as preventive care, immunomodulatory treatment, and other dietary supplements. However, these approaches often come with systemic side-effects, low bioavailability of therapeutic agents, and poor outcomes seen in the elderly. Recent innovations in nanotechnology have led to the development of novel biomaterials/nanomaterials, which explore targeted drug delivery and immunomodulatory interactions in vivo. Current nanotechnology-based immunomodulatory approaches that have the potential to be used as therapeutic interventions for some prominent age-related diseases are discussed here. Finally, we explore challenges and future aspects of nanotechnology in the treatments of age-related disorders to improve quality of life in the elderly. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Nanoparticles in the diagnosis and treatment of vascular aging and related diseases

Aging-induced alternations of vasculature structures, phenotypes, and functions are key in the occurrence and development of vascular aging-related diseases. Multiple molecular and cellular events, such as oxidative stress, mitochondrial dysfunction, vascular inflammation, cellular senescence, and epigenetic alterations are highly associated with vascular aging physiopathology. Advances in nanoparticles and nanotechnology, which can realize sensitive diagnostic modalities, efficient medical treatment, and better prognosis as well as less adverse effects on non-target tissues, provide an amazing window in the field of vascular aging and related diseases. Throughout this review, we presented current knowledge on classification of nanoparticles and the relationship between vascular aging and related diseases. Importantly, we comprehensively summarized the potential of nanoparticles-based diagnostic and therapeutic techniques in vascular aging and related diseases, including cardiovascular diseases, cerebrovascular diseases, as well as chronic kidney diseases, and discussed the advantages and limitations of their clinical applications.

Pharmacological prevention of intimal hyperplasia: A state-of-the-art review

Intimal hyperplasia (IH) occurs in a considerable number of cases of blood vessel reconstruction by stenting or balloon angioplasty, venous bypass grafting, and arteriovenous dialysis accesses. It is triggered by endothelial injury during the vascular intervention and leads to vessel restenosis with life-threatening consequences for patients. To date, the drugs used for IH prevention in clinics-paclitaxel and rapalog drugs-have been focusing primarily on the vascular smooth muscle cell (VSMC) proliferation pathway of IH development. Limitations, such as endothelial toxicity and inappropriate drug administration timing, have spurred the search for new and efficient pharmacological approaches to control IH. In this state-of-the-art review, we present the pathways of IH development, focusing on the key events and actors involved in IH. Subsequently, we discuss different drugs and drug combinations interfering with these pathways based on their effect on peripheral circulation IH models in animal studies, or on clinical reports. The reports were obtained through an extensive search of peer-reviewed publications in Pubmed, Embase, and Google Scholar, with search equations composed based on five concepts around IH and their various combinations. To improve vascular intervention outcomes, rethinking of conventional therapeutic approaches to IH prevention is needed. Exploring local application of drugs and drug combinations acting on different pathophysiological pathways of IH development has the potential to provide effective and safe restenosis prevention.

N-acetylneuraminic acid and chondroitin sulfate modified nanomicelles with ROS-sensitive H2S donor via targeting E-selectin receptor and CD44 receptor for the efficient therapy of atherosclerosis

Currently, very limited therapeutic approaches are available for the drug treatment of atherosclerosis(AS). H2S-donor is becoming a common trend in much life-threatening research. Several studies have documented that H2S-lyase is predominantly present in endothelial cells. N-Acetylneuraminic acid (SA), natural carbohydrate, binds specifically to the E-selectin receptor of endothelial cells. Meanwhile, recent studies related to Chondroitin sulfate have excellent target binding ability with CD44 receptor. We conjecture that the N-Acetylneuraminic acid and Chondroitin sulfate modified nanomicelles not only enhances the accumulation of the drug but also cleaves the H2S donor in the lesion, thus one stone two birds. Given these findings, we synthesized two kinds of nanoparticles, Carrier I (SCCF) and Carrier II (SCTM), for atherosclerosis to validate our guesses. Initially, S-allyl-L-cysteine and 4-methoxyphenylthiourea were used as H2S donors for SCCF and SCTM, respectively. After the introduction of ROS-sensitive groups. Then, micelles with N-Acetylneuraminic acid and Chondroitin sulfate were prepared to load rapamycin(RAP). Further, in atherosclerosis Oil Red O staining (ORO) results confirmed remarkable treatment effect with SCCF@RAP and SCTM@RAP. Thus, we conclude that the effect of dual-targeting nanomicelles with ROS-sensitive H2S donor based on N-Acetylneuraminic acid and Chondroitin sulfate will have a better role in atherosclerosis.

Targeted therapy of atherosclerosis by pH-sensitive hyaluronic acid nanoparticles co-delivering all-trans retinal and rapamycin

Atherosclerosis, the leading cause of death in the elderly worldwide, is typically characterized by elevated reactive oxygen species (ROS) levels and a chronic inflammatory state at the arterial plaques. Herein, pH-sensitive nanoparticles (HR_RAP NPs) co-delivering all-trans retinal (ATR), an antioxidant linked to hyaluronic acid (HA) through a pH-sensitive hydrazone bond, and rapamycin (RAP), an anti-atherosclerotic drug loaded into the nanoparticle core, are developed for targeted combination therapy of atherosclerosis. In this way, HR_RAP NPs might simultaneously reduce ROS levels via ATR antioxidant activity and reduce inflammation via the anti-inflammatory effect of RAP. In response to mildly acidic conditions mimicking the lesional inflammation in vitro, HR_RAP NPs dissociated and both ATR and RAP were effectively released. The developed HR_RAP NPs effectively inhibited pro-inflammatory macrophage proliferation, and displayed dose- and time-dependent specific internalization by different cellular models of atherosclerosis. Also, HR_RAP NP combination therapy showed an efficient synergetic anti-atherosclerotic effect in vitro by effectively inhibiting the inflammatory response and oxidative stress in inflammatory cells. More importantly, HR NPs specifically accumulated in the atherosclerotic plaques of apolipoprotein E-deficient (ApoE^-/-) mice, by active interaction with HA receptors overexpressed by different cells of the plaque. The treatment with HR_RAP NPs remarkably inhibited the progression of atherosclerosis in ApoE^-/- mice which resulted in stable plaques with considerably smaller necrotic cores, lower matrix metalloproteinase-9, and decreased proliferation of macrophages and smooth muscle cells (SMCs). Furthermore, HR_RAP NPs attenuated RAP adverse effects and exhibited a good safety profile after long-term treatment in mice. Consequently, the developed pH-sensitive HR_RAP NP represent a promising nanoplatform for atherosclerosis combination therapy.

A targeting mesoporous dopamine nanodrug platform with NIR responsiveness for atherosclerosis improvement

Atherosclerosis (AS), the formation of plaque lesions in the walls of arteries, causes many mortalities and morbidities worldwide. Currently, achieving site-specific delivery and controlled release at plaques is difficult. Herein, we implemented the strategy of constructing a bionic multifunctional nanoplatform (BM-NP) for targeting and improving plaques. BM-NPs were prepared based on probucol-loaded mesoporous polydopamine (MPDA) carriers and were coated with platelet membranes to impart bionic properties. In vitro experiments confirmed that BM-NPs, which respond to near-infrared (NIR) for drug release, remove reactive oxygen species (ROS), thereby reducing the level of oxidized low-density lipoprotein (ox-LDL) and ultimately helping to inhibit macrophage foaming. In vivo experiments proved that BM-NPs actively accumulated in plaques in the mouse right carotid artery (RCA) ligation model. During treatment, BM-NPs with NIR laser irradiation more effectively reduced the area of plaque deposition and slowed the thickening of the arterial wall intima. More importantly, BM-NPs showed the advantage of inhibiting the increase in triglyceride (TG) content in the body, and good biocompatibility. Hence, our research results indicate that intelligent BM-NPs can be used as a potential nanotherapy to precisely and synergistically improve AS.

Reactive Oxygen Species─Responsive Lipid Nanoparticles for Effective RNAi and Corneal Neovascularization Therapy

Corneal neovascularization (CNV) is a common disease that affects the vision ability of more than 1 million people annually. Small interfering RNA (siRNA) delivery nanoparticle platforms are a promising therapeutic modality for CNV treatment. However, the efficient delivery of siRNA into cells and the effective release of siRNA from delivery vehicles in a particular cell type challenge effective RNAi clinical application for CNV suppression. This study reports the design of a novel reactive oxygen species (ROS)-responsive lipid nanoparticle for siRNA delivery into corneal lesions for enhanced RNAi as a potential CNV treatment. We demonstrated that lipid nanoparticles could efficiently deliver siRNA into human umbilical vein endothelial cells and release siRNA for enhanced gene silencing by using the upregulated ROS of CNV to promote lipid nanoparticle degradation. Moreover, the subconjunctival injection of siRNA nanocomplexes into corneal lesions effectively knocked down vascular endothelial growth factor expression and suppressed CNV formation in an alkali burn model. Thus, we believe that the strategy of using ROS-responsive lipid nanoparticles for enhanced RNAi in CNV could be further extended to a promising clinical therapeutic approach to attenuate CNV formation.

Bovine serum albumin-based biomimetic gene complexes with specificity facilitate rapid re-endothelialization for anti-restenosis

Re-endothelialization is a critical problem to inhibit postoperative restenosis, and gene delivery exhibits great potential in rapid endothelialization. Unfortunately, the therapeutic effect is enormously limited by inefficient specificity, poor biocompatibility and in vivo stability owing largely to the complicated in vivo environment. Herein, we developed a series of platelet membrane (PM) cloaked gene complexes based on natural bovine serum albumin (BSA) and polyethyleneimine (PEI). The gene complexes aimed to accelerate re-endothelialization for anti-restenosis via pcDNA3.1-VEGF165 (VEGF) plasmid delivery. Based on BSA and PM coating, these gene complexes exhibited good biocompatibility, stability with serum and robust homing to endothelium-injured site inherited from platelets. Besides, they enhanced the expression of VEGF protein by their high internalization and nucleus accumulation efficiency, and also substantially promoted migration and proliferation of vascular endothelial cells. The biological properties were further optimized via altering PEI and PM content. Finally, rapid recovery of endothelium in a carotid artery injured mouse model (79% re-endothelialization compared with model group) was achieved through two weeks' treatment by the PM cloaked gene complexes. High level of expressed VEGF in vivo was also realized by the gene complexes. Moreover, neointimal hyperplasia (IH) was significantly inhibited by the gene complexes according to in vivo study. The results verified the great potential of the PM cloaked gene complexes in re-endothelialization for anti-restenosis. STATEMENT OF SIGNIFICANCE: Rapid re-endothelialization is a major challenge to inhibit postoperative restenosis. Herein, a series of biodegradable and biocompatible platelet membrane (PM) cloaked gene complexes were designed to accelerate re-endothelialization for anti-restenosis via pcDNA3.1-VEGF165 (VEGF) plasmid delivery. The PM cloaked gene complexes provided high VEGF expression in vascular endothelial cells (VECs), rapid migration and proliferation of VECs and robust homing to endothelium-injured site. In a carotid artery injured mouse model, PM cloaked gene complexes significantly promoted VEGF expression in vivo, accelerated re-endothelialization and inhibited neointimal hyperplasia due to their good biocompatibility and superior specificity. Overall, the optimized PM cloaked gene complexes overcomes multiple obstacles in gene delivery for re-endothelialization and can be a promising candidate for gene delivery and therapy of postoperative restenosis.

Nanotechnology for Cardiovascular Diseases

Cardiovascular diseases have become the major killers in today's world, among which coronary artery diseases (CADs) make the greatest contributions to morbidity and mortality. Although state-of-the-art technologies have increased our knowledge of the cardiovascular system, the current diagnosis and treatment modalities for CADs still have limitations. As an emerging cross-disciplinary approach, nanotechnology has shown great potential for clinical use. In this review, recent advances in nanotechnology in the diagnosis of CADs will first be elucidated. Both the sensitivity and specificity of biosensors for biomarker detection and molecular imaging strategies, such as magnetic resonance imaging, optical imaging, nuclear scintigraphy, and multimodal imaging strategies, have been greatly increased with the assistance of nanomaterials. Second, various nanomaterials, such as liposomes, polymers (PLGA), inorganic nanoparticles (AuNPs, MnO₂, etc.), natural nanoparticles (HDL, HA), and biomimetic nanoparticles (cell-membrane coating) will be discussed as engineered as drug (chemicals, proteins, peptides, and nucleic acids) carriers targeting pathological sites based on their optimal physicochemical properties and surface modification potential. Finally, some of these nanomaterials themselves are regarded as pharmaceuticals for the treatment of atherosclerosis because of their intrinsic antioxidative/anti-inflammatory and photoelectric/photothermal characteristics in a complex plaque microenvironment. In summary, novel nanotechnology-based research in the process of clinical transformation could continue to expand the horizon of nanoscale technologies in the diagnosis and therapy of CADs in the foreseeable future.

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Nanotechnology represents new viable approaches for diagnosis and treatment of cardiovascular diseases, the leading cause of morbidity and mortality worldwide

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Nanotechnology-assisted biosensing and molecular imaging can improve the sensitivity and specificity in the diagnosis of cardiovascular diseases

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Nanomaterials enable targeted drug delivery or directly exert therapeutic action for cardiovascular system, based on their physicochemical properties and surface modification

Progress in drug-delivery systems in cardiovascular applications: stents, balloons and nanoencapsulation

Drug-delivery systems in cardiovascular applications regularly include the use of drug-eluting stents and drug-coated balloons to ensure sufficient drug transfer and efficacy in the treatment of cardiovascular diseases. In addition to the delivery of antiproliferative drugs, the use of growth factors, genetic materials, hormones and signaling molecules has led to the development of different nanoencapsulation techniques for targeted drug delivery. The review will cover drug delivery and coating mechanisms in current drug-eluting stents and drug-coated balloons, novel innovations in drug-eluting stent technologies and drug encapsulation in nanocarriers for delivery in vascular diseases. Newer technologies and advances in nanoencapsulation techniques, such as the use of liposomes, nanogels and layer-by-layer coating to deliver therapeutics in the cardiovascular space, will be highlighted.

Recent advances in inhibiting atherosclerosis and restenosis: from pathogenic factors, therapeutic agents to nano-delivery strategies

Due to dominant atherosclerosis etiology, cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality worldwide. In clinical trials, advanced atherosclerotic plaques can be removed by angioplasty and vascular...

Remodeling the periodontitis microenvironment for osteogenesis by using a reactive oxygen species-cleavable nanoplatform

Modestly removing the excessive reactive oxygen species (ROS) plays a crucial role in regulating the microenvironment of periodontitis and provides favorable conditions for osteogenesis. However, the current strategy for scavenging ROS is not controllable, substantially limiting the outcomes in periodontitis. Herein, we introduced a controllable ROS-scavenging nanoplatform by encasing N-acetylcysteine (NAC, (a well-known ROS scavenger) into tailor-made ROS-cleavable amphiphilic polymer nanoparticles (PEG-ss-PCL NPs) as an intracellular delivery carrier. The existing ROS in the inflammatory microenvironment facilitated polymer degradation via breakage of thioketal bonds, and then led to encapsulated NAC release. NAC eliminated all ROS induced by lipopolysaccharide (LPS), while PssL-NAC adjusted the ROS level slightly higher than that of the control group. The percentage of apoptotic cells cultured with NAC and PssL-NAC decreased observably compared with that of cells cultured with 10 µg/ml LPS. The microenvironment regulated by PssL-NAC was highly suitable for osteogenic differentiation based on PCR and Western blot results, which showed higher expression levels of BMP2, Runx2, and PKA. Analysis of ALP activity and Alizarin red S staining showed consistent results. Additionally, the injection of PssL-NAC into the periodontitis area could alleviate the tissue destruction induced by ligation of the maxillary second molar. PssL-NAC showed a better ability to decrease osteoclast activity and inflammation, consequently improving the restoration of destroyed tissue. Our study suggests that ROS-responsive polymer nanoparticles loaded with NAC (PssL-NAC) can be new promising materials for the treatment of periodontitis. STATEMENT OF SIGNIFICANCE: More and more studies indicate that periodontal tissue damage is closely related to the high reactive oxygen species (ROS) environment. Excessive ROS will aggravate periodontal tissue damage and is not conducive to tissue repair. However, as an essential signal molecule in human physiological activities, ROS absence is also useless for tissue repair. In this study, we proposed to improve ROS imbalance in the environment of periodontitis as a strategy to promote periodontal regeneration and successfully synthesized a smart drug-releasing nanoplatform that can respond to ROS. Besides, we validated its ability to regulate the ROS environment and promote osteogenesis through experimental data in vivo and in vitro.

Biomimetic, ROS-detonable nanoclusters - A multimodal nanoplatform for anti-restenotic therapy

The long-term success of endovascular intervention has long been overshadowed by vessel re-occlusion, also known as restenosis. Mainstream anti-restenotic devices, such as drug-eluting stent (DES) and drug-coated balloon (DCB), were recently shown with suboptimal performances and life-threatening complications, thereby underpinning the urgent need for alternative strategies with enhanced efficacy and safety profile. In our current study, we engineered a multimodal nanocluster formed by self-assembly of unimolecular nanoparticles and surface coated with platelet membrane, specifically tailored for precision drug delivery in endovascular applications. More specifically, it incorporates the combined merits of platelet membrane coating (lesion targetability and biocompatibility), reactive oxygen species (ROS)-detonable "cluster-bomb" chemistry (to trigger the large-to-small size transition at the target site, thereby achieving longer circulation time and higher tissue penetration), and sustained drug release. Using RVX-208 (an emerging anti-restenotic drug under clinical trials) as the model payload, we demonstrated the superior performances of our nanocluster over conventional poly(lactic-co-glycolic acid) (PLGA) nanoparticle. In cultured vascular smooth muscle cell (VSMC), the drug-loaded nanocluster induced effective inhibition of proliferation and protective gene expression (e.g., APOA-I) with a significantly reduced dosage of RVX-208 (1 μM). In a rat model of balloon angioplasty, intravenous injection of Cy5.5-tagged nanocluster led to greater lesion targetability, improved biodistribution, and deeper penetration into injured vessel walls featuring enriched ROS. Moreover, in contrast to either free drug solution or drug-loaded PLGA nanoparticle formulation, a single injection with the drug-loaded nanocluster (10 mg/kg of RVX-208) was sufficient to substantially mitigate restenosis. Additionally, this nanocluster also demonstrated biocompatibility according to in vitro cytotoxicity assay and in vivo histological and tissue qPCR analysis. Overall, our multimodal nanocluster offers improved targetability, tissue penetration, and ROS-responsive release over conventional nanoparticles, therefore making it a highly promising platform for development of next-generation endovascular therapies.

Macrophage-biomimetic anti-inflammatory liposomes for homing and treating of aortic dissection

Aortic dissection (AD) is a life-threatening disease featured by the dissection of intimal layer and the formation of a blood-filled false lumen within the aortic wall. Recent studies revealed that the formation and progression of AD lesions is closely related to vascular inflammation and macrophage infiltration. However, the potential efficacy of anti-inflammatory therapy on the prevention and treatment of AD has not been extensively investigated. Herein, we proposed a biomimetic anti-inflammatory liposome (PM/TN-CCLP) co-loaded with curcumin and celecoxib (CC), modified with cell-penetrating TAT-NBD fusion peptide (TN), and further camouflaged by isolated macrophage plasma membrane (PM), as a potential nanotherapy for AD. In vitro results showed that PM/TN-CCLP exhibited low cytotoxicity and elevated cellular uptake by inflammatory macrophages, and prominently inhibited the transendothelial migration, inflammatory responses and ROS generation of macrophages. Moreover, the PM/TN-CCLP treatment significantly prevented the H₂O₂-induced smooth muscle cell apoptosis. In vivo experiments were performed on the acute and chronic AD mouse models, respectively. The results verified the elevated accumulation of PM-camouflaged liposome at the aorta lesions. Further, the anti-inflammatory liposomes, especially PM/TN-CCLP, could reduce the rupture rate of dissection, prevent the loss of elastic fibers, and reduce MMP-9 expression as well as macrophage infiltration in the aortic lesions. Notably, as compared with free drugs and TN-CCLP, the PM/TN-CCLP treatment displayed the longest survival period along with the minimal aortic injury on both acute and chronic AD mice. Taken together, the present study suggested that the macrophage-biomimetic anti-inflammatory nanotherapy would be a promising strategy for the prevention and therapy of aortic dissection.

An improved in vitro model for studying the structural and functional properties of the endothelial glycocalyx in arteries, capillaries and veins

The endothelial glycocalyx is a dynamic structure integral to blood vessel hemodynamics and capable of tightly regulating a range of biological processes (ie, innate immunity, inflammation, and coagulation) through dynamic changes in its composition of the brush structure. Evaluating the specific roles of the endothelial glycocalyx under a range of pathophysiologic conditions has been a challenge in vitro as it is difficult to generate functional glycocalyces using commonly employed 2D cell culture models. We present a new multi-height microfluidic platform that promotes the growth of functional glycocalyces by eliciting unique shear stress forces over a continuous human umbilical vein endothelial cell monolayer at magnitudes that recapitulate the physical environment in arterial, capillary and venous regions of the vasculature. Following 72 hours of shear stress, unique glycocalyx structures formed within each region that were distinct from that observed in short (3 days) and long-term (21 days) static cell culture. The model demonstrated glycocalyx-specific properties that match the characteristics of the endothelium in arteries, capillaries and veins, with respect to surface protein expression, platelet adhesion, lymphocyte binding and nanoparticle uptake. With artery-to-capillary-to-vein transition on a continuous endothelial monolayer, this in vitro platform is an improved system over static cell culture for more effectively studying the role of the glycocalyx in endothelial biology and disease.

Inflammatory microenvironment-targeted nanotherapies

Inflammatory microenvironments (IMEs) are common pathological characteristics and drive the development of multiple chronic diseases. Thus, IME-targeted therapies exhibit potential for the treatment of inflammatory diseases. Nanoplatforms have significant advantages in improving the efficiency of anti-inflammatory treatments. Owing to their improved therapeutic effects and reduced side effects, IME-targeted nanotherapies have recently drawn interest from the research community. This review introduces IMEs and discusses the application of IME-targeted nanotherapies for inflammatory diseases. The development of rational targeting strategies tailored to IMEs in damaged tissues can help promote therapies for chronic diseases.

Catalogue of self-targeting nano-medical inventions to accelerate clinical trials

Repetitive outbreaks and prolonged epidemics represent mortal threats to global health, creating chaos in our globalized world. To date, scientists have been compelled to follow FDA guidelines for conventional clinical trials, which decelerates the release of effective therapies to battle outbreaks and safeguard global health security. Developing multi-purpose platform nanotechnologies to self-target specific organs in response to the disease microenvironment could greatly help to rapidly anticipate and efficiently manage outbreaks. Nano-interventions in the form of self-targeting nanoparticles (NPs) could accelerate the clinical translation of potential drugs to fight future outbreaks via innovating their clinical trials. This review sets the foundation of the self-targeting concept to govern the in vivo fate of NPs without the need to complicate the engineering designs with targeting ligands. The proposed catalogue of accelerated nano-innovations offers self-targeting, physiological trafficking, bio-compliance, and controllable drug release in response to associated smart linkers.

Inflammation-responsive delivery systems for the treatment of chronic inflammatory diseases

Inflammation is the biological response of immune system to protect living organisms from injurious factors. However, excessive and uncontrolled inflammation is implicated in a variety of devastating chronic diseases including atherosclerosis, inflammatory bowel disease (IBD), and rheumatoid arthritis (RA). Improved understanding of inflammatory response has unveiled a rich assortment of anti-inflammatory therapeutics for the treatment and management of relevant chronic diseases. Notwithstanding these successes, clinical outcomes are variable among patients and serious adverse effects are often observed. Moreover, there exist some limitations for clinical anti-inflammatory therapeutics such as aqueous insolubility, low bioavailability, off-target effects, and poor accessibility to subcellular compartments. To address these challenges, the rational design of inflammation-specific drug delivery systems (DDSs) holds significant promise. Moreover, as compared to normal tissues, inflamed tissue-associated pathological milieu (e.g., oxidative stress, acidic pH, and overexpressed enzymes) provides vital biochemical stimuli for triggered delivery of anti-inflammatory agents in a spatiotemporally controlled manner. In this review, we summarize recent advances in the development of anti-inflammatory DDSs with built-in pathological inflammation-specific responsiveness for the treatment of chronic inflammatory diseases.

Applications of Nanobiomaterials in the Therapy and Imaging of Acute Liver Failure

This review focuses on the therapeutic mechanisms, targeting strategies of various nanomaterials in acute liver failure, and recent advances of diverse nanomaterials for acute liver failure therapy, diagnosis, and imaging. This review provides an outlook on the applications of nanomaterials, especially on the new horizons in acute liver failure therapy, and inspires broader interests across various disciplines. Acute liver failure (ALF), a fatal clinical disease featured with overwhelming hepatocyte necrosis, is a grand challenge in global health. However, a satisfactory therapeutic option for curing ALF is still absent, other than liver transplantation. Nanobiomaterials are currently being developed for the diagnosis and treatment of ALF. The liver can sequester most of nanoparticles from blood circulation, which becomes an intrinsic superiority for nanobiomaterials targeting hepatic diseases. Nanobiomaterials can enhance the bioavailability of free drugs, thereby significantly improving the therapeutic effects in ALF. Nanobiomaterials can also increase the liver accumulation of therapeutic agents and enable more effective targeting of the liver or specific liver cells. In addition, stimuli-responsive, optical, or magnetic nanomaterials exhibit great potential in the therapeutical, diagnostic, and imaging applications in ALF. Therefore, therapeutic agents in combination with nanobiomaterials increase the specificity of ALF therapy, diminish adverse systemic effects, and offer a multifunctional theranostic platform. Nanobiomaterial holds excellent significance and prospects in ALF theranostics. In this review, we summarize the therapeutic mechanisms and targeting strategies of various nanobiomaterials in ALF. We highlight recent developments of diverse nanomedicines for ALF therapy, diagnosis, and imaging. Furthermore, the challenges and future perspectives in the theranostics of ALF are also discussed.

Design Strategies and Applications of ROS-Responsive Phenylborate Ester-Based Nanomedicine

Reactive oxygen species (ROS)-responsive nanomedicine has been extensively developed to improve the therapeutic effects while reducing the systemic toxicity. ROS, as important biological metabolites and signaling molecules, are known to overexpress in most of tumors and inflammations. Among various ROS-sensitive moieties, phenylborate ester (PBAE) with easy modifiable structure and excellent biocompatibility, represents one of the most ROS-sensitive structures. To harness it as a switch, the past several years had witnessed a booming of ROS-sensitive PBAE-based nanomedicine for various medical purposes. Much of the efforts were devoted to exploiting the potential in the management of antitumor and anti-inflammation. This review first summarizes the design strategies of PBAE in the construction of nanomedicine, with PBAE acting as not only the ROS-responsive unit, but also the roles of hydrophobic backbone or bridging segment in the macromolecular structures. The ROS-responsive mechanisms are then briefly discussed. Afterward, we focus on the introduction of the state-of-the-art research on ROS-responsive PBAE-based nanomedicine for antitumor and anti-inflammation applications. The conclusion and future perspectives of ROS-responsive nanomedicine are also provided.

Bioresponsive drug delivery systems for the treatment of inflammatory diseases

Inflammation is intimately related to the pathogenesis of numerous acute and chronic diseases like cardiovascular disease, inflammatory bowel disease, rheumatoid arthritis, and neurodegenerative diseases. Therefore anti-inflammatory therapy is a very promising strategy for the prevention and treatment of these inflammatory diseases. To overcome the shortcomings of existing anti-inflammatory agents and their traditional formulations, such as nonspecific tissue distribution and uncontrolled drug release, bioresponsive drug delivery systems have received much attention in recent years. In this review, we first provide a brief introduction of the pathogenesis of inflammation, with an emphasis on representative inflammatory cells and mediators in inflammatory microenvironments that serve as pathological fundamentals for rational design of bioresponsive carriers. Then we discuss different materials and delivery systems responsive to inflammation-associated biochemical signals, such as pH, reactive oxygen species, and specific enzymes. Also, applications of various bioresponsive drug delivery systems in the treatment of typical acute and chronic inflammatory diseases are described. Finally, crucial challenges in the future development and clinical translation of bioresponsive anti-inflammatory drug delivery systems are highlighted.

Targeting and deep-penetrating delivery strategy for stented coronary artery by magnetic guidance and ultrasound stimulation

Stent placement is an effective treatment for atherosclerosis, but is suffered from in-stent restenosis (ISR) caused by stent mechanical damage. Conventional ISR treatment such as drug-eluting stents (DES) is challenged by the low therapeutic efficacy and severe complications, unchangeable drug dosage for individuals, and limited drug penetration in the vascular tissue. We hypothesize that magnetic targeting and deep-penetrating delivery strategy by magnetic guidance and ultrasound stimulation might be an effective approach for ISR treatment. In the present study, antiproliferative drug (paclitaxel, PTX) loaded poly (lactide-co-glycolide) (PLGA) nanoparticles (PLGA-PTX) were embedded within the shells of the magnetic nanoparticle coated microbubbles (MMB-PLGA-PTX). Once being targeted to the stent under a magnetic field, a low intensity focused ultrasound (LIFU) is applied to activate stable microbubble oscillations, thereby triggering the release of PLGA-PTX. The generated mechanical force and microstreaming facilitate the penetration of released PLGA-PTX into the thickened vascular tissue and enhance their internalization by smooth muscle cells (SMCs), thereby reducing the clearance by blood flow. In an ex vivo experiment, magnetic targeting improved the accumulation amount of MMB-PLGA-PTX by 10 folds, while the LIFU facilitated the penetration of released PLGA-PTX into the tunica media region of the porcine coronary artery, resulting in prolonged retention time at the stented vascular tissue. With the combination effects, this strategy holds great promise in the precision delivery of antiproliferative drugs to the stented vascular tissue for ISR treatment.

Biomedical Application of Reactive Oxygen Species-Responsive Nanocarriers in Cancer, Inflammation, and Neurodegenerative Diseases

Numerous pathological conditions, including cancer, inflammatory diseases, and neurodegenerative diseases, are accompanied by overproduction of reactive oxygen species (ROS). This makes ROS vital flagging molecules in disease pathology. ROS-responsive drug delivery platforms have been developed. Nanotechnology has been broadly applied in the field of biomedicine leading to the progress of ROS-responsive nanoparticles. In this review, we focused on the production and physiological/pathophysiological impact of ROS. Particular emphasis is put on the mechanisms and effects of abnormal ROS levels on oxidative stress diseases, including cancer, inflammatory disease, and neurodegenerative diseases. Finally, we summarized the potential biomedical applications of ROS-responsive nanocarriers in these oxidative stress diseases. We provide insights that will help in the designing of new ROS-responsive nanocarriers for various applications.

Silencing of long non-coding RNA Sox2ot inhibits oxidative stress and inflammation of vascular smooth muscle cells in abdominal aortic aneurysm via microRNA-145-mediated Egr1 inhibition

Long non-coding RNAs (lncRNAs) have been largely reported to contribute to the development and progression of abdominal aortic aneurysm (AAA), a common vascular degenerative disease. The present study was set out with the aim to investigate the possible role of lncRNA Sox2ot in the development of AAA. In this study, we found that lncRNA Sox2ot and early growth response factor-1 (Egr1) were highly expressed, while microRNA (miR)-145 was poorly expressed in Ang II-induced AAA mice and oxidative stress-provoked vascular smooth muscle cell (VSMC) model. Egr1 was a potential target gene of miR-145, and lncRNA Sox2ot could competitively bind to miR-145 to upregulate Egr1 expression. Overexpression of miR-145-5p was found to attenuate oxidative stress and inflammation by inhibiting Egr1 both in vivo and in vitro, which was counteracted by lncRNA Sox2ot. Taken together, the present study provides evidence that downregulation of lncRNA Sox2ot suppressed the expression of Egr1 through regulating miR-145, thus inhibiting the development of AAA, highlighting a theoretical basis for AAA treatment.

Targeted Repair of Vascular Injury by Adipose-Derived Stem Cells Modified with P-Selectin Binding Peptide

Percutaneous coronary intervention for coronary artery disease treatment often results in pathological vascular injury, characterized by P-selectin overexpression. Adipose-derived stem cells (ADSCs) therapeutic efficacy remains elusive due to poor ADSCs targeting and retention in injured vessels. Here, conjugated P-selectin binding peptide (PBP) to polyethylene glycol-conjugated phospholipid derivative (DMPE-PEG) linkers (DMPE-PEG-PBP; DPP) are used to facilitate the modification of PBP onto ADSCs cell surfaces via hydrophobic interactions between DMPE-PEG and the phospholipid bilayer. DPP modification neither has influence on ADSCs proliferation nor apoptosis/paracrine factor gene expression. A total of 5 × 10^-6 m DPP-modified ADSCs (DPP-ADSCs) strongly binds to P-selectin-displaying activated platelets and endothelial cells (ECs) in vitro and to wire-injured rat femoral arteries when administered by intra-arterial injection. Targeted binding of ADSCs shields injury sites from platelet and leukocyte adhesion, thereby decreasing inflammation at injury sites. Furthermore, targeted binding of ADSCs recovers injured ECs functionality and reduces platelet-initiated vascular smooth muscle cells (VSMCs) chemotactic migration. Targeted binding of DPP-human ADSCs to balloon-injured human femoral arteries is also demonstrated in ex vivo experiments. Overall, DPP-ADSCs promote vascular repair, inhibit neointimal hyperplasia, increase endothelium functionality, and maintain normal VSMCs alignment, supporting preclinical noninvasive utilization of DPP-ADSCs for vascular injury.

Antioxidant Nanotherapies for the Treatment of Inflammatory Diseases

Reactive oxygen species (ROS) are essential in regulating various physiological functions. However, overproduction of ROS is implicated in the pathogenesis of various inflammatory diseases. Antioxidant therapy has thus represented an effective strategy for the treatment of oxidative stress relevant inflammatory diseases. Conventional anti-oxidative agents showed limited in vivo effects owing to their non-specific distribution and low retention in disease sites. Over the past decades, significant achievements have been made in the development of antioxidant nanotherapies that exhibit multiple advantages such as excellent pharmacokinetics, stable anti-oxidative activity, and intrinsic ROS-scavenging properties. This review provides a comprehensive overview on recent advances in antioxidant nanotherapies, including ROS-scavenging inorganic nanoparticles, organic nanoparticles with intrinsic antioxidant activity, and drug-loaded anti-oxidant nanoparticles. We highlight the biomedical applications of antioxidant nanotherapies in the treatment of different inflammatory diseases, with an emphasis on inflammatory bowel disease, cardiovascular disease, and brain diseases. Current challenges and future perspectives to promote clinical translation of antioxidant nanotherapies are also briefly discussed.

Cyclodextrin polymer improves atherosclerosis therapy and reduces ototoxicity

Recently, cyclodextrin (CD) has shown the potential for effective treatment of atherosclerotic plaques in mice by solubilizing plaque cholesterol. While promising as a new therapy for atherosclerosis, poor pharmacokinetics and ototoxicity of CD pose a therapeutic challenge. Thus far, however, there has been no attempts to overcome such limitations. Here, we showed that cyclodextrin polymer (CDP) with a diameter of ~ 10 nm exhibits outstanding pharmacokinetics and plaque targeting efficacy compared to a monomeric CD. Furthermore, we found out that CDP does not induce plasma membrane disruption as opposed to CD, which eliminated cytotoxicity and hemolytic activity of CD. In a mouse model of atherosclerosis, subcutaneous injections of beta-cyclodextrin polymer (βCDP) significantly inhibited plaque growth compared to monomeric hydroxypropyl-beta-cyclodextrin (HPβCD) at the same dose (1 g/kg). More importantly, βCDP did not induce significant ototoxicity at a high-dose (8 g/kg) where HPβCD reduced the outer hair cell content by 36%. These findings suggest that the polymerization of CD can overcome major limitations of CD therapy for treatment of atherosclerosis.

Ginsenoside Rg3-loaded, reactive oxygen species-responsive polymeric nanoparticles for alleviating myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a serious threat to the health and lives of patients without any effective therapy. Excessive production of reactive oxygen species (ROS) is considered a principal cause of MIRI. Some natural products, including ginsenoside Rg3 (Rg3), exhibit robust antioxidant activity. However, the lack of an effective delivery strategy for this hydrophobic compound hinders its clinical application. In addition, therapeutic targets and molecular mechanisms of Rg3 require further elucidation to establish its mode of action. This study aimed to generate ROS-responsive nanoparticles (PEG-b-PPS) via the self-assembly of diblock copolymers of poly (ethylene glycol) (PEG) and poly (propylene sulfide) (PPS) and use them for Rg3 encapsulation and delivery. We identified FoxO3a as the therapeutic target of Rg3 using molecular docking and gene silencing. In rat ischemia-reperfusion model, an intramyocardial injection of Rg3-loaded PEG-b-PPS nanoparticles improved the cardiac function and reduced the infarct size. The mechanism of action was established as Rg3 targeting of FoxO3a, which inhibited the promotion of oxidative stress, inflammation, and fibrosis via downstream signaling pathways. In conclusion, this approach, involving ROS-responsive drug release, together with the identification of the target and mechanism of action of Rg3, provided an effective strategy for treating ischemic diseases and oxidative stress and could accelerate the implementation of hydrophobic natural products in clinical applications.

A pH/ROS dual-responsive and targeting nanotherapy for vascular inflammatory diseases

Cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality worldwide. Vascular inflammation is closely related to the pathogenesis of a diverse group of CVDs. Currently, it remains a great challenge to achieve site-specific delivery and controlled release of therapeutics at vascular inflammatory sites. Herein we hypothesize that active targeting nanoparticles (NPs) simultaneously responsive to low pH and high levels of reactive oxygen species (ROS) can serve as an effective nanoplatform for precision delivery of therapeutic cargoes to the sites of vascular inflammation, in view of acidosis and oxidative stress at inflamed sites. The pH/ROS dual-responsive NPs were constructed by combination of a pH-sensitive material (ACD) and an oxidation-responsive material (OCD) that can be facilely synthesized by chemical functionalization of β-cyclodextrin, a cyclic oligosaccharide. Simply by regulating the weight ratio of ACD and OCD, the pH/ROS responsive capacity can be easily modulated, affording NPs with varied hydrolysis profiles under inflammatory microenvironment. Using rapamycin (RAP) as a candidate drug, we first demonstrated in vitro therapeutic advantages of RAP-containing NPs with optimal dual-responsive capability, i.e. RAP/AOCD NP, and a non-responsive nanotherapy (RAP/PLGA NP) and two single-responsive nanotherapies (RAP/ACD NP and RAP/OCD NP) were used as controls. In an animal model of vascular inflammation in rats subjected to balloon injury in carotid arteries, AOCD NP could accumulate at the diseased site after intravenous (i.v.) injection. Consistently, i. v. treatment with RAP/AOCD NP more effectively inhibited neointimal hyperplasia in rats with induced arterial injuries, compared to RAP/PLGA NP, RAP/ACD NP, and RAP/OCD NP. By surface decoration of AOCD NP with a peptide (KLWVLPKGGGC) targeting type IV collagen (Col-IV), the obtained Col-IV targeting, dual-responsive nanocarrier TAOCD NP showed dramatically increased accumulation at injured carotid arteries. Furthermore, RAP/TAOCD NP exhibited significantly potentiated in vivo efficacy in comparison to the passive targeting nanotherapy RAP/AOCD NP. Importantly, in vitro cell culture experiments and in vivo animal studies in both mice and rats revealed good safety for AOCD NP and RAP/AOCD NP, even after long-term treatment via i. v. injection. Consequently, our results demonstrated that the newly developed Col-IV targeting, pH/ROS dual-responsive NPs may serve as an effective and safe nanovehicle for precision therapy of arterial restenosis and other vascular inflammatory diseases.

Reactive oxygen species-responsive drug delivery systems for the treatment of neurodegenerative diseases

Neurodegenerative diseases and disorders seriously impact memory and cognition and can become life-threatening. Current medical techniques attempt to combat these detrimental effects mainly through the administration of neuromedicine. However, drug efficacy is limited by rapid dispersal of the drugs to off-target sites while the site of administration is prone to overdose. Many neuropathological conditions are accompanied by excessive reactive oxygen species (ROS) due to the inflammatory response. Accordingly, ROS-responsive drug delivery systems have emerged as a promising solution. To guide intelligent and comprehensive design of ROS-responsive drug delivery systems, this review article discusses the two following topics: (1) the biology of ROS in both healthy and diseased nervous systems and (2) recent developments in ROS-responsive, drug delivery system design. Overall, this review article would assist efforts to make better decisions about designing ROS-responsive, neural drug delivery systems, including the selection of ROS-responsive functional groups.

A Proresolving Peptide Nanotherapy for Site-Specific Treatment of Inflammatory Bowel Disease by Regulating Proinflammatory Microenvironment and Gut Microbiota

The incidence and prevalence of inflammatory bowel disease (IBD) increases steadily worldwide. There is an urgent need for effective and safe IBD therapies. Accelerated resolution of inflammation is a new strategy for the management of inflammatory diseases. For effective and safe IBD treatment, herein a smart nanotherapy (i.e. oxidation-responsive nanoparticles containing a proresolving annexin A1-mimetic peptide Ac2-26, defined as AON) is developed, which can release packaged Ac2-26, in response to highly expressed reactive oxygen species (ROS) at diseased sites. AON effectively protects Ac2-26 from degradation in the enzyme-rich environment of the gastrointestinal tract. By delivering this nanotherapy to the inflamed colons of mice with IBD, site-specific release and accumulation of Ac2-26 in response to high levels of ROS at the inflammatory sites are achieved. Mechanistically, the Ac2-26-containing, oxidation-labile nanotherapy AON effectively decreases the expression of proinflammatory mediators, attenuates trafficking and infiltration of inflammatory cells, promotes efferocytosis of apoptotic neutrophils, and increases phenotypic switching of macrophages. Therapeutically, AON reduces symptoms of inflammation, accelerates intestinal mucosal wound healing, reshapes the gut microbiota composition, and increases short-chain fatty acid production. Additionally, oral delivery of this nanomedicine shows excellent safety profile in a mouse model, conferring the confidence for further development of a targeted precision therapy for IBD and other inflammatory diseases.

A Targeting Nanotherapy for Abdominal Aortic Aneurysms

BACKGROUND

Abdominal aortic aneurysm (AAA) is a leading cause of mortality and morbidity in the elderly. Currently, there remain no effective drugs that can prevent the growth of aneurysms and delay aneurysm rupture in the clinical setting.

OBJECTIVES

The aim of this study was to develop a nanotherapy that can target aneurysms and release drug molecules in response to the inflammatory microenvironment.

METHODS

Using a reactive oxygen species (ROS)-responsive nanoparticle and a candidate drug rapamycin, in combination with a peptide ligand for integrin and biomimetic cloaking with macrophage cell membrane, a nanotherapy was developed. Its effectiveness was demonstrated by in vitro and in vivo studies.

RESULTS

Based on a facile and translational method, a rapamycin-loaded responsive nanotherapy was successfully prepared, which could release drug molecules upon triggering by the high level of ROS. In cells associated with the development of AAAs, the nanotherapy significantly inhibited calcification and attenuated ROS-mediated oxidative stress and apoptosis. By passively targeting aneurysms and releasing drug molecules in response to the inflammatory microenvironment, the intravenously injected ROS-responsive nanotherapy more effectively prevented aneurysm expansion in AAA rats than a nonresponsive control nanotherapy. After decoration with a peptide ligand cRGDfK and macrophage cell membrane, the aneurysmal targeting capability and therapeutic effects of a ROS-responsive nanotherapy with a mean diameter of 190 nm were further enhanced. Moreover, the nanotherapy showed a good safety profile in a preliminary safety test.

CONCLUSIONS

The multifunctional nanotherapy can be further studied as a promising targeted drug for treatment of aneurysms. The underlying design principles enable the development of a broad range of nanomedicines for targeted therapy of other vascular diseases.

Engineering Cell Membrane-Based Nanotherapeutics to Target Inflammation

Inflammation is ubiquitous in the body, triggering desirable immune response to defend against dangerous signals or instigating undesirable damage to cells and tissues to cause disease. Nanomedicine holds exciting potential in modulating inflammation. In particular, cell membranes derived from cells involved in the inflammatory process may be used to coat nanotherapeutics for effective targeted delivery to inflammatory tissues. Herein, the recent progress of rationally engineering cell membrane-based nanotherapeutics for inflammation therapy is highlighted, and the challenges and opportunities presented in realizing the full potential of cell-membrane coating in targeting and manipulating the inflammatory microenvironment are discussed.

Nanotherapies for Treatment of Cardiovascular Disease: A Case for Antioxidant Targeted Delivery

Purpose of Review

Cardiovascular disease (CVD) involves a broad range of clinical manifestations resulting from a dysfunctional vascular system. Overproduction of reactive oxygen and nitrogen species are causally implicated in the severity of vascular dysfunction and CVD. Antioxidant therapy is an attractive avenue for treatment of CVD associated pathologies. Implementation of targeted nano-antioxidant therapies has the potential to overcome hurdles associated with systemic delivery of antioxidants. This review examines the currently available options for nanotherapeutic targeting CVD, and explores successful studies showcasing targeted nano-antioxidant therapy.

Recent Findings

Active targeting strategies in the context of CVD heavily focus on immunotargeting to inflammatory markers like cell adhesion molecules, or to exposed extracellular matrix components. Targeted antioxidant nanotherapies have found success in pre-clinical studies.

Summary

This review underscores the potential of targeted nanocarriers as means of finding success translating antioxidant therapies to the clinic, all with a focus on CVD.

A Multifunctional Nanotherapy for Targeted Treatment of Colon Cancer by Simultaneously Regulating Tumor Microenvironment

Colitis-associated colon cancer (CAC) is a widely recognized cancer, while treatment with the existing chemotherapeutic drugs affords limited clinical benefits. Herein we proposed a site-specific, combination nanotherapy strategy for targeted treatment of CAC by the oral route. Methods: A reactive oxygen species (ROS)-responsive and hydrogen peroxide-eliminating material OCD was synthesized, which was further produced into a functional nanoparticle (OCD NP). The antioxidative stress and anti-inflammatory effects of OCD NP were examined by in vitro and in vivo experiments. By packaging an anticancer drug camptothecin-11 (CPT-11) into OCD NP, a ROS-responsive nanotherapy CPT-11/OCD NP was obtained, and its antitumor activity was evaluated by both in vitro and in vivo studies. Preliminary safety studies were also performed for CPT-11/OCD NP in mice. Results: OCD NP significantly attenuated oxidative stress and inhibited inflammatory response in different cells and mice with induced colitis. CPT-11/OCD NP could selectively release drug molecules under intestinal pH conditions and at high levels of ROS. In C26 murine colon carcinoma cells, this nanotherapy showed significantly higher antitumor activity compared to free CPT-11 and a non-responsive CPT-11 nanotherapy. Correspondingly, oral delivery of CPT-11/OCD NP notably inhibited tumorigenesis and tumor growth in mice with induced CAC. By combination therapy with the nanovehicle OCD NP in the inflammatory phase, more desirable therapeutic effects were achieved. Furthermore, CPT-11/OCD NP displayed excellent safety profile for oral administration at a dose that is 87.3-fold higher than that employed in therapeutic studies. Conclusions: Anticancer nanotherapies derived from intrinsic anti-inflammatory nanocarriers are promising for targeted combination treatment of inflammation-associated tumors by simultaneously shaping pro-inflammatory microenvironment toward a relatively normal niche sensitive to chemotherapy.

Reactive oxygen species (ROS)-responsive biomaterials mediate tissue microenvironments and tissue regeneration

ROS-responsive biomaterials alleviate the oxidative stress in tissue microenvironments, promoting tissue regeneration and disease therapy.

A Broad-Spectrum ROS-Eliminating Material for Prevention of Inflammation and Drug-Induced Organ Toxicity

Despite the great potential of numerous antioxidants for pharmacotherapy of diseases associated with inflammation and oxidative stress, many challenges remain for their clinical translation. Herein, a superoxidase dismutase/catalase-mimetic material based on Tempol and phenylboronic acid pinacol ester simultaneously conjugated β-cyclodextrin (abbreviated as TPCD), which is capable of eliminating a broad spectrum of reactive oxygen species (ROS), is reported. TPCD can be easily synthesized by sequentially conjugating two functional moieties onto a β-cyclodextrin scaffold. The thus developed pharmacologically active material may be easily produced into antioxidant and anti-inflammatory nanoparticles, with tunable size. TPCD nanoparticles (TPCD NP) effectively protect macrophages from oxidative stress-induced apoptosis in vitro. Consistently, TPCD NP shows superior efficacies in three murine models of inflammatory diseases, with respect to attenuating inflammatory responses and mitigating oxidative stress. TPCD NP can also protect mice from drug-induced organ toxicity. Besides the passive targeting effect, the broad spectrum ROS-scavenging capability contributes to the therapeutic benefits of TPCD NP. Importantly, in vitro and in vivo preliminary experiments demonstrate the good safety profile of TPCD NP. Consequently, TPCD in its native and nanoparticle forms can be further developed as efficacious and safe therapies for treatment of inflammation and oxidative stress-associated diseases.

Entropically driven controlled release of paclitaxel from poly(2-ethyl-2-oxazoline) coated maghemite nanostructures for magnetically guided cancer therapy

Theranostic nanostructures serve a dual purpose of therapy and diagnosis. A major fraction of these are based on polymer coated magnetic nanostructures of iron oxides (magnetite and maghemite), owing to the efficient drug loading capacity of polymer shells and enhanced magnetic contrast effects of the iron oxide core. In the current work we are proposing poly(2-ethyl-2-oxazoline) coated linear thermoresponsive nanostructures of maghemite (γ-Fe₂O₃) for potential application in targeted cancer therapy. The polymer coating was obtained via a modified sol-gel technique based on entropically driven phase separation of poly(2-ethyl-2-oxazoline) above its cloud point (CP) temperature of 63 °C in water. The developed nanostructures were further loaded with paclitaxel, a polar anticancer compound at room temperature (25 °C). The entropically driven release of paclitaxel at various concentrations and physiological temperatures was modeled and their application to the PC3 prostrate cancer cell line was investigated by treating in vitro. The steering efficiency of the magnetic nanostructures during their navigation through large blood vessels was also analyzed with the help of a synthetic model of the human axillary artery. The proposed application of these newly developed nanostructures can easily be extended towards localized delivery of additional polar anticancer drugs like cisplatin and doxorubicin.