Cerium oxide nanoparticles attenuate monocrotaline induced right ventricular hypertrophy following pulmonary arterial hypertension

Ceria nanoparticles: biomedical applications and toxicity

Ceria nanoparticles (CeO2 NPs) have become popular materials in biomedical and industrial fields due to their potential applications in anti-oxidation, cancer therapy, photocatalytic degradation of pollutants, sensors, etc. Many methods, including gas phase, solid phase, liquid phase, and the newly proposed green synthesis method, have been reported for the synthesis of CeO2 NPs. Due to the wide application of CeO2 NPs, concerns about their adverse impacts on human health have been raised. This review covers recent studies on the biomedical applications of CeO2 NPs, including their use in the treatment of various diseases (e.‍g., Alzheimer's disease, ischemic stroke, retinal damage, chronic inflammation, and cancer). CeO2 NP toxicity is discussed in terms of the different systems of the human body (e.‍g., cytotoxicity, genotoxicity, respiratory toxicity, neurotoxicity, and hepatotoxicity). This comprehensive review covers both fundamental discoveries and exploratory progress in CeO2 NP research that may lead to practical developments in the future.

Pulmonary arterial hypertension nanotherapeutics: New pharmacological targets and drug delivery strategies

Pulmonary arterial hypertension (PAH) is a rare, serious, and incurable disease characterized by high lung pressure. PAH-approved drugs based on conventional pathways are still not exhibiting favorable therapeutic outcomes. Drawbacks like short half-lives, toxicity, and teratogenicity hamper effectiveness, clinical conventionality, and long-term safety. Hence, approaches like repurposing drugs targeting various and new pharmacological cascades and/or loaded in non-toxic/efficient nanocarrier systems are being investigated lately. This review summarizes the status of conventional, repurposed, either in vitro, in vivo, and/or in clinical trials of PAH treatment. In-depth description, discussion, and classification of the new pharmacological targets and nanomedicine strategies with a description of all the nanocarriers that showed promising efficiency in delivering drugs are discussed. Ultimately, an illustration of the different nucleic acids tailored and nanoencapsulated within different types of nanocarriers to restore the pathways affected by this disease is presented.

Hyperoside Prevents Aβ42-Induced Neurotoxicity in PC12 Cells and Caenorhabditis elegans

Traditional Chinese medicines such as hyperoside-rich Acanthopanax senticosus and Crataegus pinnatifida have been confirmed to exhibit anti-oxidative stress properties. Hyperoside, the main ingredient of numerous antioxidant herbs, may have the ability to postpone the onset of neurodegenerative diseases. This study investigates the possible therapeutic mechanism of hyperoside as a natural antioxidant against Alzheimer's disease (AD) in Caenorhabditis elegans and PC12 cells. Specifically, hyperoside reduced reactive oxygen species (ROS) level and Aβ42-induced neurotoxicity in C. elegans worms. Meanwhile, hyperoside reduced ROS production and increased mitochondrial membrane potentialin Aβ42-induced PC12 cells, which possibly due to the increase of antioxidant enzymes activity and the diminution of malondialdehyde levels. Hoechst 33,342 staining and flow cytometry analysis results suggested that hyperoside reverses cell apoptosis. Network pharmacology predicts potentially relevant hyperoside targets and pathways in AD therapy. As anticipated, hyperoside reversed Aβ42-stimulated downregulation of the PI3K/Akt/Nrf2/HO-1. The PI3K inhibitor LY294002 partially abolished the protective capability of hyperoside. The results of molecular docking further indicated that the PI3K/Akt pathways may be involved in the protection of Aβ42-induced PC12 cells by hyperoside treatment. The study provides theoretical information for research and development of hyperoside as an antioxidant dietary supplement.

Recent Advances on Cerium Oxide-Based Biomaterials: Toward the Next Generation of Intelligent Theranostics Platforms

Disease or organ damage due to unhealthy living habits, or accidents, is inevitable. Discovering an efficient strategy to address these problems is urgently needed in the clinic. In recent years, the biological applications of nanotechnology have received extensive attention. Among them, as a widely used rare earth oxide, cerium oxide (CeO2 ) has shown good application prospects in biomedical fields due to its attractive physical and chemical properties. Here, the enzyme-like mechanism of CeO2 is elucidated, and the latest research progress in the biomedical field is reviewed. At the nanoscale, Ce ions in CeO2 can be reversibly converted between +3 and +4. The conversion process is accompanied by the generation and elimination of oxygen vacancies, which give CeO2 the performance of dual redox properties. This property facilitates nano-CeO2 to catalyze the scavenging of excess free radicals in organisms, hence providing a possibility for the treatment of oxidative stress diseases such as diabetic foot, arthritis, degenerative neurological diseases, and cancer. In addition, relying on its excellent catalytic properties, customizable life-signaling factor detectors based on electrochemical techniques are developed. At the end of this review, an outlook on the opportunities and challenges of CeO2 in various fields is provided.

Pegylated nanoceria: A versatile nanomaterial for noninvasive treatment of retinal diseases

Oxidative stress induced reactive oxygen species has been implicated as the primary molecular mechanism in the pathogenesis of debilitating retinal diseases such as diabetic retinopathy, neovascularization and age-related macular degeneration. Nanoceria (cerium oxide nanoparticles) has recently received much attention, because of its superior and regenerative radical scavenging properties. This review focuses on retinal applications of nanoceria and functionalized nanoceria. Studies in animal models showed that nanoceria possess antioxidant, anti-inflammatory, anti-angiogenic, anti-apoptotic properties and preserves retinal morphology and prevents loss of retinal functions. Nanoceria have been tested in animal models of age-related macular degeneration and neovascularization and their efficacy have been shown to persist for a long time, without any collateral effects. To date, several pharmaceutical formulations of nanoceria have been developed for their prospective clinical ophthalmic applications such as chitosan coated nanoceria, nanoceria loaded into hydrogels, nanoceria embedded in wafers and contact lens and organosilane or polyethylene glycol functionalized nanoceria. Based on their nano size range, ocular permeation could be achieved to allow topical administration of nanoceria. PEGylation of nanoceria represents the key strategy to support eye drop formulation with enhanced corneal permeation, without altering chemical physical properties. Based on their excellent antioxidant properties, nano-size, safety and tolerability, PEGylated nanoceria represent a new potential therapeutic for the treatment.

Natural Targeting Potent ROS-Eliminating Tungsten-Based Polyoxometalate Nanodots for Efficient Treatment of Pulmonary Hypertension

Pulmonary hypertension (PH) is a disease of pulmonary artery stenosis and blockage caused by abnormal pulmonary artery smooth muscle cells (PASMCs), with high morbidity and mortality. High levels of reactive oxygen species (ROS) in pulmonary arteries play a crucial role in inducing phenotypic switch and abnormal proliferation of PASMCs. However, antioxidants are rarely approved for the treatment of PH because of a lack of targeting and low bioavailability. In this study, the presence of an enhanced permeability and retention effect (EPR)-like effect in the pulmonary arteries of PH is revealed by tissue transmission electron microscopy (TEM). Subsequently, for the first time, tungsten-based polyoxometalate nanodots (WNDs) are developed with potent elimination of multiple ROS for efficient treatment of PH thanks to the high proportion of reduced W5+ . WNDs are effectively enriched in the pulmonary artery by intravenous injection because of the EPR-like effect of PH, and significantly prevent the abnormal proliferation of PASMCs, greatly improve the remodeling of pulmonary arteries, and ultimately improve right heart function. In conclusion, this work provides a novel and effective solution to the dilemma of targeting ROS for the treatment of PH.

Antioxidant and Prooxidant Nanozymes: From Cellular Redox Regulation to Next-Generation Therapeutics

Nanozymes, nanomaterials with enzyme-mimicking activity, have attracted tremendous interest in recent years owing to their ability to replace natural enzymes in various biomedical applications, such as biosensing, therapeutics, drug delivery, and bioimaging. In particular, the nanozymes capable of regulating the cellular redox status by mimicking the antioxidant enzymes in mammalian cells are of great therapeutic significance in oxidative-stress-mediated disorders. As the distinction of physiological oxidative stress (oxidative eustress) and pathological oxidative stress (oxidative distress) occurs at a fine borderline, it is a great challenge to design nanozymes that can differentially sense the two extremes in cells, tissues and organs and mediate appropriate redox chemical reactions. In this Review, we summarize the advances in the development of redox-active nanozymes and their biomedical applications. We primarily highlight the therapeutic significance of the antioxidant and prooxidant nanozymes in various disease model systems, such as cancer, neurodegeneration, and cardiovascular diseases. The future perspectives of this emerging area of research and the challenges associated with the biomedical applications of nanozymes are described.

Nanomedicine-mediated therapeutic approaches for pulmonary arterial hypertension

Nanomedicine has emerged as a field in which there are opportunities to improve the diagnosis, treatment and prevention of incurable diseases. Pulmonary arterial hypertension (PAH) is known as a severe and fatal disease affecting children and adults. Conventional treatments have not produced optimal effectiveness in treating this condition. Several reasons for this include drug instability, poor solubility of the drug and a shortened duration of pharmacological action. The present review focuses on new approaches for delivering anti-PAH drugs using nanotechnology with the aim of overcoming these shortcomings and increasing their efficacy. Solid-lipid nanoparticles, liposomes, metal-organic frameworks and polymeric nanoparticles have demonstrated advantages for the potential treatment of PAH, including increased drug bioavailability, drug solubility and accumulation in the lungs.

Cardioprotective Effects of Nanoparticles in Cardiovascular Diseases: A State-of-the-Art Review

It has been reported that death related to cardiovascular disease has increased up to 12.5% just in the past decade alone with various factors playing a role. In 2015 alone, it has been estimated that there were 422.7 million cases of CVD with 17.9 million deaths. Various therapies have been discovered to control and treat CVDs and their complications including reperfusion therapies and pharmacological approaches but many patients still progress to heart failure. Due to these proven adverse effects of existing therapies, various novel therapeutic techniques have emerged in the near past. Nano formulation is one of them. It is a practical therapeutic strategy to minimize pharmacological therapy's side effects and nontargeted distribution. Nanomaterials are suitable for treating CVDs due to their small size, which enables them to reach more sites of the heart and arteries. The biological safety, bioavailability, and solubility of the drugs have been increased due to the encapsulation of natural products and their derivatives of drugs.

Nanozyme-Enabled Treatment of Cardio- and Cerebrovascular Diseases

Cardio- and cerebrovascular diseases are two major vascular-related diseases that lead to death worldwide. Reactive oxygen species (ROS) play a vital role in the occurrence and exacerbation of diseases. Excessive ROS induce cellular context damage and lead to tissue dysfunction. Nanozymes, as emerging enzyme mimics, offer a unique perspective for therapy through multifunctional activities, achieving essential results in the treatment of ROS-related cardio- and cerebrovascular diseases by directly scavenging excess ROS or regulating pathologically related molecules. This review first introduces nanozyme-enabled therapeutic mechanisms at the cellular level. Then, the therapies for several typical cardio- and cerebrovascular diseases with nanozymes are discussed, mainly including cardiovascular diseases, ischemia reperfusion injury, and neurological disorders. Finally, the challenges and outlooks for the application of nanozymes are also presented. This review will provide some instructive perspectives on nanozymes and promote the development of enzyme-mimicking strategies in cardio- and cerebrovascular disease therapy.

Biomimetic Nanozymes Suppressed Ferroptosis to Ameliorate Doxorubicin-Induced Cardiotoxicity via Synergetic Effect of Antioxidant Stress and GPX4 Restoration

Mitochondria-dependent ferroptosis plays an important role in the pathogenesis of doxorubicin (DOX)-induced cardiotoxicity (DIC), which remains a clinical challenge due to the lack of effective interventions. Cerium oxide (CeO₂), a representative nanozyme, has attracted much attention because of its antioxidant properties. This study evaluated CeO₂-based nanozymes for the prevention and treatment of DIC in vitro and in vivo by adding nanoparticles (NPs), which were synthesized by biomineralization, to the culture or giving them to the mice, and the ferroptosis-specific inhibitor ferrostatin-1 (Fer-1) was used as control. The prepared NPs exhibited an excellent antioxidant response and glutathione peroxidase 4 (GPX4)-depended bioregulation, with the additional merits of bio-clearance and long retention in the heart. The experiments showed that NP treatment could significantly reverse myocardial structural and electrical remodeling, and reduce myocardial necrosis. These cardioprotective therapeutic effects were associated with their ability to alleviate oxidative stress, mitochondrial lipid peroxidation, and mitochondrial membrane potential damage, with a superior efficiency to the Fer-1. The study also found that the NPs significantly restored the expression of GPX4 and mitochondrial-associated proteins, thereby restoring mitochondria-dependent ferroptosis. Therefore, the study provides some insights into the role of ferroptosis in DIC. It also shows that CeO₂-based nanozymes could be a promising prevention and treatment candidate as a novel cardiomyocyte ferroptosis protector to mitigate DIC and improve prognosis and quality of life in cancer patients.

Recent Advances in ROS-Scavenging Metallic Nanozymes for Anti-Inflammatory Diseases: A Review

Oxidative stress and dysregulated inflammatory responses are the hallmarks of inflammatory disorders, which are key contributors to high mortality rates and impose a substantial economic burden on society. Reactive oxygen species (ROS) are vital signaling molecules that promote the development of inflammatory disorders. The existing mainstream therapeutic approaches, including steroid and non-steroidal anti-inflammatory drugs, and proinflammatory cytokine inhibitors with anti-leucocyte inhibitors, are not efficient at curing the adverse effects of severe inflammation. Moreover, they have serious side effects. Metallic nanozymes (MNZs) mimic the endogenous enzymatic process and are promising candidates for the treatment of ROS-associated inflammatory disorders. Owing to the existing level of development of these metallic nanozymes, they are efficient at scavenging excess ROS and can resolve the drawbacks of traditional therapies. This review summarizes the context of ROS during inflammation and provides an overview of recent advances in metallic nanozymes as therapeutic agents. Furthermore, the challenges associated with MNZs and an outline for future to promote the clinical translation of MNZs are discussed. Our review of this expanding multidisciplinary field will benefit the current research and clinical application of metallic-nanozyme-based ROS scavenging in inflammatory disease treatment.

In vitro and in vivo evaluation of cerium oxide nanoparticles in respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is the most common cause of viral bronchiolitis among children worldwide, yet there is no vaccine for RSV disease. This study investigates the potential of cube and sphere-shaped cerium oxide nanoparticles (CNP) to modulate reactive oxygen (ROS) and nitrogen (RNS) species and immune cell phenotypes in the presence of RSV infection in vitro and in vivo. Cube and sphere-shaped CNP were synthesized by hydrothermal and ultrasonication methods, respectively. Physico-chemical characterization confirmed the shape of sphere and cube CNP and effect of various parameters on their particle size distribution and zeta potential. In vitro results revealed that sphere and cube CNP differentially modulated ROS and RNS levels in J774 macrophages. Specifically, cube CNP significantly reduced RSV-induced ROS levels without affecting RNS levels while sphere CNP increased RSV-induced RNS levels with minimal effect on ROS levels. Cube CNP drove an M1 phenotype in RSV-infected macrophages in vitro by increasing macrophage surface expression of CD80 and CD86 with a concomitant increase in TNFα and IL-12p70, while simultaneously decreasing M2 CD206 expression. Intranasal administration of sphere and cube-CNP were well-tolerated with no observed toxicity in BALB/c mice. Notably, cube CNP preferentially accumulated in murine alveolar macrophages and induced their activation, avoiding enhanced uptake and activation of other inflammatory cells such as neutrophils, which are associated with RSV-mediated inflammation. In conclusion, we report that sphere and cube CNP modulate macrophage polarization and innate cellular responses during RSV infection.

Protective effect of cerium oxide on testicular function and oxidative stress after torsion/detorsion in adult male rats

Testicular torsion (T)/detorsion (D) can cause testicular injury due to the rotation of the spermatic cord and its vessels, therefore it represents an urological emergency that is surgically treated. Oxidative damage occurs in the testis and distant organs because of the overproduction of free radicals and overexpression of proinflammatory cytokines by reperfusion after surgery. Cerium oxide (CeO₂) nanoparticles, a material also known as nanoceria, have regenerative antioxidant properties on oxidative stress. The present study aimed to investigate the effects of nanoceria on testis tissues in testicular T/D in rats. A total of 24 rats were equally and randomly divided into four groups: Control, CeO₂, T/D and CeO2-T/D groups. Left inguinoscrotal incision was performed in the control group. In the CeO₂ group, 0.5 mg/kg CeO₂ was given intraperitoneally 30 min before inguinoscrotal incision. In the T/D group, unilateral testicular T/D was performed through an inguinoscrotal incision and rotating the left testis 720˚ clockwise, which was then left ischemic for 120 min, followed by 120 min of reperfusion. In the CeO₂-T/D group, 0.5 mg/kg CeO₂ was given intraperitoneally 30 min before testicular T/D. At the end of the experiment, testis tissues were removed for histopathological and biochemical examinations. The samples were histologically examined, Glutathione-s transferase (GST), catalase (CAT), paraoxonase (PON) activities and malondialdehyde (MDA) levels were measured via biochemical analysis methods, while the expression levels of p53, Bax and Bcl-2 were detected using immunohistochemistry. The present results revealed statistically significant inter-group differences in PON, CAT and GST activities and MDA levels. GST, CAT and PON activities were significantly higher, whereas MDA levels in the CeO₂-T/D group were significantly lower compared with those in the T/D group. The T/D group had increased Bax and decreased Bcl-2 expression levels in their seminiferous tubules compared with the control and CeO₂ groups. CeO₂ treatment led to downregulation of Bax and upregulation of Bcl-2. The expression of p53 was high in the T/D group compared with that in the control and CeO2 groups, and was upregulated in all germinal cells. However, compared with that in the T/D group, p53 expression was significantly decreased in the CeO₂-T/D group. The testicular injury score significantly increased in the CeO₂-T/D group compared with the control and CeO₂ groups. Rats in the CeO₂-T/D group demonstrated significantly milder tissue lesions compared with those in T/D group. The present findings indicated that nanoceria may protect testis in rats against the harmful effects of T/D. Further studies are required to evaluate how CeO₂ reduces oxidative stress and cell death in testis tissue that underwent T/D-related injury.

Nanoceria, the versatile nanoparticles: Promising biomedical applications

Nanotechnology has been a boon for the biomedical field due to the freedom it provides for tailoring of pharmacokinetic properties of different drug molecules. Nanomedicine is the medical application of nanotechnology for the diagnosis, treatment and/or management of the diseases. Cerium oxide nanoparticles (CNPs) are metal oxide-based nanoparticles (NPs) which possess outstanding reactive oxygen species (ROS) scavenging activities primarily due to the availability of "oxidation switch" on their surface. These NP have been found to protect from a number of disorders with a background of oxidative stress such as cancer, diabetes etc. In fact, the CNPs have been found to possess the environment-dependent ROS modulating properties. In addition, the inherent catalase, SOD, oxidase, peroxidase and phosphatase mimetic properties of CNPs provide them superiority over a number of NPs. Further, chemical reactivity of CNPs seems to be a function of their surface chemistry which can be precisely tuned by defect engineering. However, the contradictory reports make it necessary to critically evaluate the potential of CNPs, in the light of available literature. The review is aimed at probing the feasibility of CNPs to push towards the clinical studies. Further, we have also covered and censoriously discussed the suspected negative impacts of CNPs before making our way to a consensus. This review aims to be a comprehensive, authoritative, critical, and accessible review of general interest to the scientific community.

Reactive-oxygen-species-scavenging nanomaterials for resolving inflammation

Reactive oxygen species (ROS) mediate multiple physiological functions; however, the over-accumulation of ROS causes premature aging and/or death and is associated with various inflammatory conditions. Nevertheless, there are limited clinical treatment options that are currently available. The good news is that owing to the considerable advances in nanoscience, multiple types of nanomaterials with unique ROS-scavenging abilities that influence the temporospatial dynamic behaviors of ROS in biological systems have been developed. This has led to the emergence of next-generation nanomaterial-controlled strategies aimed at ameliorating ROS-related inflammatory conditions. Accordingly, herein we reviewed recent progress in research on nanotherapy based on ROS scavenging. The underlying mechanisms of the employed nanomaterials are emphasized. Furthermore, important issues in developing cross-disciplinary nanomedicine-based strategies for ROS-based inflammatory conditions are discussed. Our review of this increasing interdisciplinary field will benefit ongoing studies and clinical applications of nanomedicine based on ROS scavenging.

Galectin-3 participates in PASMC migration and proliferation by interacting with TGF-β1

Pulmonary vascular remodelling is one of the most important factors for pulmonary hypertension (PH). Galectin-3 (Gal-3) is a β-galactoside-binding lectin. In the latest literature, Gal-3 has been reported to be involved in pulmonary vascular remodelling, and its underlying mechanism is unclear. Our research aims to prove the effect of Gal-3 on the proliferation and migration of human pulmonary artery smooth muscle cells (HPASMC) induced by transforming growth factor β1 (TGF-β1) and to study its mechanism. In vivo experiment: In Sprague-Dawley (SD) rats, monocrotaline was injected intraperitoneally to establish a PH model, and the Gal-3 inhibitor (modified citrus pectin, MCP) 28 Ds was administered in the stomach. The results indicate that Gal-3 and TGF-β1 may be involved in the occurrence and development of PH, which may be related to the Smad2/3 signalling pathway. In vitro experiment: Human pulmonary artery smooth muscle cells were pretreated with the Gal-3 inhibitor (MCP) for 24 h, then TGF-β1 or Gal-3 was administered to the cells for 24 h. The results show that exogenous TGF-β1 and Gal-3 can activate the downstream Smad2/3 signalling pathway, and increase the proliferation and migration ability of HPASMC. However, the Gal-3 inhibitor (MCP) inhibited these effects. Further results display that TGF-β1 and Gal-3 could mutually regulate the protein and mRNA expression levels. In summary, the results of this study indicate that Gal-3 regulates the Smad2/3 signalling pathway through protein interaction with TGF-β1, in turn regulates the proliferation and migration of HPASMC, thereby regulating the occurrence and development of PH.

Antioxidant metal oxide nanozymes: role in cellular redox homeostasis and therapeutics

Nanomaterials with enzyme-like activity, generally referred to as ‘nanozymes’, find myriad potential in various biomedical fields. More importantly, the nanoparticles that can functionally mimic the activity of cellular antioxidant enzymes attract tremendous interest owing to their possible therapeutic candidature in oxidative stress-mediated disorders. Oxidative stress culminating due to excess reactive oxygen species (ROS) level and dysregulated cellular antioxidant machinery is implicated in the development and progression of various pathophysiological disorders such as cancer, diabetes, cardiovascular and neurodegenerative diseases. Moreover, the optimum essentiality of ROS due to its pivotal role in cell signaling evokes the requirement of novel artificial antioxidant enzymes that can circumvent the detrimental effects of enhanced ROS levels without perturbing the basal redox status of cells. In recent years, the fast emanating artificial enzymes, i.e. nanozymes with antioxidant enzyme-like activity, has made tremendous progress with their broad applications in therapeutics, diagnostic medicine, bio-sensing, and immunoassay. Among various antioxidant nanoparticles reported till-date, the metal oxide nanozymes have emerged as the most efficient and successful candidates in mimicking the activity of first-line defense antioxidant enzymes, i.e. superoxide dismutase, catalase, and glutathione peroxidase. This review intends to exclusively highlight the development of representative metal oxide-based antioxidant nanozymes capable of maintaining the cellular redox homeostasis and their potential therapeutic significance.

Anti-Inflammatory Effects of Cerium Dioxide Nanoparticles on Peritonitis in Rats Induced by Staphylococcus epidermidis Infection

Objective. To investigate the effects of cerium dioxide (CeO2) nanoparticles on the inflammatory response of peritonitis rats induced by Staphylococcus epidermidis infection. Methods. Green tea polyphenol CeO2 nanoparticles were synthesized and characterized by transmission microscopy, ultraviolet-visible spectroscopy, FT-IR, and powder diffractometer. 40 male adult SD rats were randomly divided into 4 groups (n = 10 each): a control group, a model group, a CeO2 group, and a CeO2 + model group. Staphylococcus epidermidis solution was injected intraperitoneally with 107 CFU/ml of bacterial solution in the model group, while the control group was injected intraperitoneally with the same amount of normal saline, and the CeO2 and CeO2 + model groups were injected with 0.5 mg/kg CeO2 nanoparticles through the tail vein for 2 h and then injected with saline or bacterial solution for 2 h, respectively. After 0 h, 3 h, 12 h, 24 h, and 48 h of model construction, rats were sacrificed, and serum and peritoneal lavage fluid were collected. The total number of leukocytes and the percentage of each type of leukocytes in the peritoneal lavage fluid were determined. Enzyme-linked immunosorbent assay (ELISA) was used to detect the level of inflammatory factor TNF-α in serum and peritoneal lavage fluid, and myeloperoxidase (MPO) activity in peritoneal tissue was also measured. In addition, real-time fluorescence quantitative PCR (RT-PCR) was used to measure the expression of TLR2 and TLR4 in peritoneal tissue, and western blotting was used to detect the expression of TLR2, TLR4, and the activation of NF-κB signaling pathways as well. Results. The CeO2 has an average size of 37 ± 3 nm with binding activity to proteins, phenolic compounds, and alkaloids. After counting the white blood cells in the peritoneal lavage fluid, it was found that the total number of white blood cells and the percentage of neutrophils in the model group were significantly increased (both P<0.05), and CeO2 treatment significantly reversed the above changes (both P<0.05). The ELISA results showed that compared with the control group, the TNF-α in the peritoneal lavage fluid and serum of the model group increased in a time-dependent manner (all P<0.05); however, there was no significant change in the CeO2 group (P>0.05); at the same time in the CeO2 + model group, the TNF-α content was significantly reduced (all P<0.05). Detection of MPO activity in peritoneal tissue revealed that MPO activity was significantly increased under peritonitis (all P<0.05), and CeO2 treatment could mitigate that increase (all P<0.05). RT-PCR results showed that compared with the control group, the expression of TLR2 and TLR4 mRNA levels in the peritoneum of the model group were increased in a time-dependent manner (all P<0.05), and there was no significant change in the CeO2 group (P>0.05); however, TLR2 and TLR4 mRNA levels were significantly reduced in the CeO2 + model group (all P<0.05). Western blotting test was performed on the peritoneal tissue collected after 48 h of the model establishment. Compared with the control group, the levels of TLR2, TLR4, p–NF–κB, and p-IκBα protein in the model group were significantly increased (all P<0.05), while CeO2 group showed no significant changes (P>0.05) and administration of CeO2 before model construction can significantly reverse the above protein activation (all P<0.05). Conclusion. CeO2 nanoparticles have anti-inflammatory effects in peritonitis caused by Staphylococcus epidermidis infection.

Cerium- and Iron-Oxide-Based Nanozymes in Tissue Engineering and Regenerative Medicine

Nanoparticulate materials displaying enzyme-like properties, so-called nanozymes, are explored as substitutes for natural enzymes in several industrial, energy-related, and biomedical applications. Outstanding high stability, enhanced catalytic activities, low cost, and availability at industrial scale are some of the fascinating features of nanozymes. Furthermore, nanozymes can also be equipped with the unique attributes of nanomaterials such as magnetic or optical properties. Due to the impressive development of nanozymes during the last decade, their potential in the context of tissue engineering and regenerative medicine also started to be explored. To highlight the progress, in this review, we discuss the two most representative nanozymes, namely, cerium- and iron-oxide nanomaterials, since they are the most widely studied. Special focus is placed on their applications ranging from cardioprotection to therapeutic angiogenesis, bone tissue engineering, and wound healing. Finally, current challenges and future directions are discussed.

Nanomaterials with enzyme-like characteristics (nanozymes): next-generation artificial enzymes (II)

An updated comprehensive review to help researchers understand nanozymes better and in turn to advance the field.

Biomedical applications of nanoceria: new roles for an old player

The use of different biomaterials with the ability to accelerate the repair and regeneration processes is of great importance in tissue engineering strategies. On this point, cerium oxide nanoparticles (CNPs or nanoceria) have recently attracted much attention due to their excellent biological properties including anti-oxidant, anti-inflammation and antibacterial activities as well as high angiogenic potential. The results of incorporation of these nano-sized particles into various constructs and scaffolds designed for tissue engineering applications have proven the success of this strategy in terms of improving healing process of different tissues. In this review, we first summarize the physicochemical and biological properties of nanoceria in brief and then present its usability in tissue engineering strategies based on the currently available published reports.

Cardioprotective effects of nanoceria in a murine model of cardiac remodeling

Isoproterenol (ISO), a synthetic β₁ adrenergic agonist is a well-known agent to be associated with severe cardiotoxicity manifested as marked myocardial necrosis and fibrosis. Oxidative stress plays a crucial role in mediating ISO induced cardiotoxicity. In present study, we have investigated the possible protective effect of nanoceria (NC) in ISO induced cardiac injury. We have given long duration exposure (a total of 10 days) of low dose ISO (20 mg/kg/day) to investigate the protective effects of NC in chronic cardiac injury model. ISO (20 mg/kg/day for 10 days) produced cardiac injury as evident by increased plasma LDH and CK-MB, AST, ALT, cardiac hypertrophy, severe myocardial fibrosis (MF) and significantly higher levels of cytokines, IL-6, TGF-β and TNF-α. Interestingly, the treatment with NC (0.2 and 2 mg/kg) abrogated cardiotoxicity symptoms and provided protection from ISO induced cardiac injury. The results from present study demonstrated strong evidences of cardioprotective effects of NC as shown by reduction in the levels of LDH (p < 0.05 at 2 mg/kg) and CK-MB (p < 0.05 at 2 mg/kg). In addition, NC reduced oxidative stress parameters MDA (p < 0.05 at 2 mg/kg) and enhanced GSH levels which is physiological antioxidant (p < 0.01 at both doses). Further, NC exhibited promising anti-inflammatory activity and curbed the levels of cytokines (p < 0.05 at 0.2 mg/kg and p < 0.001 for IL-1β and p < 0.001 at both doses for IL-6). In addition, NC also reduced the levels of pro-fibrotic cytokine, TGF-β (p < 0.05 at 2 mg/kg) and helped in reduction of collagen deposition in heart thereby, preventing the myocardial remodeling. Our results strongly suggested that NC might be of potential use as a cardioprotective agent.

Toxicity and tissue distribution of cerium oxide nanoparticles in rats by two different routes: single intravenous injection and single oral administration

Toxicity and target organ distribution of cerium oxide nanoparticles (CeNPs) were investigated via single intravenous injection and single oral administration, respectively. Rats were sacrificed at 24 h after treatment with doses of 30 and 300 mg/kg, and cerium concentrations were measured in liver, kidney, spleen, lung, blood, urine and feces. Results revealed cerium levels in blood and tissues were considerably low in oral treated groups and most cerium was detected in feces, meaning CeNPs would not be absorbed in the gastro-intestinal system. Conversely, high concentrations of cerium were detected in all tissues of rats after intravenous injection. Liver and spleen were main target organs. Cerium levels in liver were 594.9 ± 95.3 μg/g tissue in 30 mg/kg treat group and 3741.7 ± 932.7 μg/g tissue in 300 mg/kg treat group. Cerium levels in spleen reached almost levels of liver. Cerium was also detected, that is relatively low compared to oral administration, in feces of rats treated via intravenous injection, that supports biliary excretion of CeNPs. Urine excretion of CeNPs was not detected in oral treatment and intravenous injection. In accordance with level of cerium distribution, toxicities based on hematology, serum biochemistry and histopathology were observed in rats treated by intravenous injection while no significance was revealed in orally treated groups.

Effects of CeO2 nanoparticles on the HO-1, NQO1, and GCLC expression in the testes of diabetic rats

CeO₂ nanoparticles (CNPs) as effective ROS scavengers exhibit potent antioxidant activity. In this study the effect of CNPs investigated was on HO-1, NQO1, and GCLC expression in the streptozotocin (STZ)-induced diabetic rats. Twenty-four male Wistar rats were divided into 4 groups: controls did not receive any treatment; diabetic rats received STZ (60 mg/kg daily); CNPs group received CNPs 30 mg/kg daily for 2 weeks; and rats in STZ + CNPs group received CNPs 30 mg/kg daily for 2 weeks following STZ injection. Oxidative stress was evaluated by measurement of total antioxidant capacity (TAC) and total oxidative status (TOS levels). HO-1, NQO1, and GCLC expression was measured using quantitative real-time PCR. Following STZ injection, significant lower levels of TAC and higher levels of TOS were observed. CNPs could alleviate deleterious effects of diabetes through the enhancement of TAC levels and a significant decline in TOS levels. HO-1, NQO1, and GCLC expression in the diabetic rats were lower than controls. HO-1, NQO1, and GCLC was upregulated in the diabetic rats treated with CNPs. There were significant correlations between NQO1 and GCLC, NQO1 and HO-1, and between HO-1 and GCLC expression. Moreover, Nrf2 was associated with NQO1, GCLC, and HO-1 expression. CNPs as Nrf2 upregulator confer protection against oxidative stress in the testes of STZ-induced diabetic rats by upregulating HO-1, GCLC, and NQO1 cytoprotective genes.

Treatment strategies for the right heart in pulmonary hypertension

The function of the right ventricle (RV) determines the prognosis of patients with pulmonary hypertension. While much progress has been made in the treatment of pulmonary hypertension, therapies for the RV are less well established. In this review of treatment strategies for the RV, first we focus on ways to reduce wall stress since this is the main determinant of changes to the ventricle. Secondly, we discuss treatment strategies targeting the detrimental consequences of increased RV wall stress. To reduce wall stress, afterload reduction is the essential. Additionally, preload to the ventricle can be reduced by diuretics, by atrial septostomy, and potentially by mechanical ventricular support. Secondary to ventricular wall stress, left-to-right asynchrony, altered myocardial energy metabolism, and neurohumoral activation will occur. These may be targeted by optimising RV contraction with pacing, by iron supplement, by angiogenesis and improving mitochondrial function, and by neurohumoral modulation, respectively. We conclude that several treatment strategies for the right heart are available; however, evidence is still limited and further research is needed before clinical application can be recommended.

Global Proteomics Deciphered Novel-Function of Osthole Against Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a progressive cardiovascular-disease with high mortality lacking high-efficiency drug. Our efforts attempted to delineate therapeutic action of osthole produced by Angelica Pubescens Maxim, which has the capacity to treat PAH by exploiting an iTRAQ-based proteomic method. Excitingly, osthole was observed to significantly restore 98 of 315 differential proteins significantly modified by PAH progression. They were primarily annotated into 24 signaling pathways. Four mostly affected proteins (RPL15, Cathepsin S, Histone H3.3 and HMGB1) were experimentially validated which belonged to ribosome pathway, oxidative phosphorylation pathway, systemic lupus erythematosus pathway, complement and coagulation cascades pathway, whose modifications and modulations mostly accounted for therapeutic capacity of this compound against PAH. Altogether, our findings demonstrated that global proteomics is a promising systems-biology approach for deciphering therapeutic actions and associated mechanisms of natural products derived from traditional Chinese medicine. Importantly, osthole is supposed to be a candidate compound for new drug development to treat PAH.

Analytical High-resolution Electron Microscopy Reveals Organ-specific Nanoceria Bioprocessing

This is the first utilization of advanced analytical electron microscopy methods, including high-resolution transmission electron microscopy, high-angle annular dark field scanning transmission electron microscopy, electron energy loss spectroscopy, and energy-dispersive X-ray spectroscopy mapping to characterize the organ-specific bioprocessing of a relatively inert nanomaterial (nanoceria). Liver and spleen samples from rats given a single intravenous infusion of nanoceria were obtained after prolonged (90 days) in vivo exposure. These advanced analytical electron microscopy methods were applied to elucidate the organ-specific cellular and subcellular fate of nanoceria after its uptake. Nanoceria is bioprocessed differently in the spleen than in the liver.

Baicalein attenuates monocrotaline-induced pulmonary arterial hypertension by inhibiting vascular remodeling in rats

BACKGROUND

Pulmonary arterial hypertension (PAH) is a devastating cardiopulmonary disorder characterized by elevated pulmonary arterial pressure (PAP) and right ventricular hypertrophy (RVH) driven by progressive vascular remodeling. Reversing adverse vascular remodeling is an important concept in the treatment of PAH. Endothelial injury, inflammation, and oxidative stress are three main contributors to pulmonary vascular remodeling. Baicalein is a natural flavonoid that has been shown to possess anti-proliferative, anti-inflammatory, anti-oxidative, and cardioprotective properties. We hypothesized that baicalein may prevent the progression of PAH and preserve the right heart function by inhibiting pulmonary arterial remodeling.

METHODS

Male Sprague-Dawley rats were distributed randomly into 4 groups: control, monocrotaline (MCT)-exposed, and MCT-exposed plus baicalein treated rats (50 and 100 mg/kg/day for 2 weeks). Hemodynamic changes, RVH, and lung morphological features were examined on day 28. Apoptosis was determined by TUNEL staining, and the mRNA levels of tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and IL-6 were detected by qRT-PCR. The changes in oxidative indicators, including malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were measured using corresponding commercial kits. The levels of Bax, Bcl-2, and cleaved caspase-3, and the activation of mitogen-activated protein kinase (MAPK) and NF-κB were assessed by western blotting.

RESULTS

MCT induced an increase in hemodynamic parameters and RVH, which were attenuated by baicalein treatment. Baicalein also blocked MCT-induced pulmonary arterial remodeling. The levels of apoptotic (Bax/Bcl-2 ratio and cleaved caspase-3) and inflammatory (IL-6, TNF-α, and IL-1β) biomarkers in lung tissue were lower in baicalein-treated groups. Baicalein also decreased MDA level, and increased SOD and GSH-Px activity in rat pulmonary tissue. Furthermore, baicalein inhibited MCT-induced activation of the MAPK and NF-κB pathways.

CONCLUSION

Baicalein ameliorates MCT-induced PAH by inhibiting pulmonary arterial remodeling at least partially via the MAPK and NF-κB pathways in rats.

Hilaire C, Hortells L, Phillippi JA, Sant V, Sant S. Shape-Specific Nanoceria Mitigate Oxidative Stress-Induced Calcification in Primary Human Valvular Interstitial Cell Culture

INTRODUCTION

Lack of effective pharmacological treatment makes valvular calcification a significant clinical problem in patients with valvular disease and bioprosthetic/mechanical valve replacement therapies. Elevated levels of reactive oxygen species (ROS) in valve tissue have been identified as a prominent hallmark and driving factor for valvular calcification. However, the therapeutic value of ROS-modulating agents for valvular calcification remains elusive. We hypothesized that ROS-modulating shape-specific cerium oxide nanoparticles (CNPs) will inhibit oxidative stress-induced valvular calcification. CNPs are a class of self-regenerative ROS-modulating agents, which can switch between Ce3+ and Ce4+ in response to oxidative microen-vironment. In this work, we developed oxidative stress-induced valve calcification model using two patient-derived stenotic valve interstitial cells (hVICs) and investigated the therapeutic effect of shape-specific CNPs to inhibit hVIC calcification.

METHODS

Human valvular interstitial cells (hVICs) were obtained from a normal healthy donor and two patients with calcified aortic valves. hVICs were characterized for their phenotypic (mesenchymal, myofibroblast and osteoblast) marker expression by qRT-PCR and antioxidant enzymes activity before and after exposure to hydrogen peroxide (H2O2)-induced oxidative stress. Four shape-specific CNPs (sphere, short rod, long rod, and cube) were synthesized via hydrothermal or ultra-sonication method and characterized for their biocompatibility in hVICs by alamarBlue® assay, and ROS scavenging ability by DCFH-DA assay. H2O2 and inorganic phosphate (Pi) were co-administrated to induce hVIC calcification in vitro as demonstrated by Alizarin Red S staining and calcium quantification. The effect of CNPs on inhibiting H2O2-induced hVIC calcification was evaluated.

RESULTS

hVICs isolated from calcified valves exhibited elevated osteoblast marker expression and decreased antioxidant enzyme activities compared to the normal hVICs. Due to the impaired antioxidant enzyme activities, acute H2O2-induced oxidative stress resulted in higher ROS levels and osteoblast marker expression in both diseased hVICs when compared to the normal hVICs. Shape-specific CNPs exhibited shape-dependent abiotic ROS scavenging ability, and excellent cytocompatibility. Rod and sphere CNPs scavenged H2O2-induced oxidative stress in hVICs in a shape- and dose-dependent manner by lowering intracellular ROS levels and osteoblast marker expression. Further, CNPs also enhanced activity of antioxidant enzymes in hVICs to combat oxidative stress. Cube CNPs were not effective ROS scavengers. The addition of H2O2 in the Pi-induced calcification model further increased calcium deposition in vitro in a time-dependent manner. Co-administration of rod CNPs with Pi and H2O2 mitigated calcification in the diseased hVICs.

CONCLUSIONS

We demonstrated that hVICs derived from calcified valves exhibited impaired antioxidant defense mechanisms and were more susceptible to oxidative stress than normal hVICs. CNPs scavenged H2O2-induced oxidative stress in hVICs in a shape-dependent manner. The intrinsic ROS scavenging ability of CNPs and their ability to induce cellular antioxidant enzyme activities may confer protection from oxidative stress-exacerbated calcification. CNPs represent promising antioxidant therapy for treating valvular calcification and deserve further investigation.

In vivo ameliorative effect of cerium oxide nanoparticles in isoproterenol-induced cardiac toxicity

BACKGROUND

Cerium oxide nanoparticles have gained much more attention especially in the field of nanomedicine. This work represents cerium oxide nanoparticles as a new prophylactic model for heart failure progression.

OBJECTIVE

To investigate the potential protective effect of cerium oxide nanoparticles on Isoproterenol (ISO)-induced cardiac toxicity in rats.

METHODS

Cerium oxide nanoparticles (5±1nm) were synthesized by reverse micelle method and characterized using High Resolution Transmission Electron Microscopy, X-Ray Diffraction and particle size analyzer. The experiments were performed on 96 male Wistar rats. The rats were randomly allocated into eight groups. Namely; two Negative and positive control groups, captopril administered group, Nano-ceria (low dose) group, Nano-ceria (high dose) group, Captopril- Isoproterenol group, Nano-ceria (low dose)-Isoproterenol group and Nano-ceria (high dose)-Isoproterenol group. Cardio toxic rat model was induced by subcutaneous administration of Isoproterenol (ISO) (30mg/kg) for two consecutive days in adult male rats. Two doses (0.5 and 5μg/kg/week) of cerium oxide nanoparticles were applied for five weeks and 50mg/kg/day of Captopril was used as a reference drug. Cardiac marker enzymes, Cortisol and Aldosterone hormones were assessed in serum. Oxidant-antioxidant parameters and histopathological examination in heart tissues were also determined.

RESULTS

These dose of nano-ceria, showed a promising ameliorative and prophylactic effect against cardiac toxicity compared to Captopril reference drug. Serum cardiac markers were decreased by noticeable percentage, CK-MB (50% and 57%), LDH (47% and 57.7%), AST (38% and 36.5%) and ALT (33.5% and 30.6%) for both doses respectively, while increased tissues level of the antioxidant enzymes, catalase (48% - 26%) and superoxide dismutase (64%, 143%).

CONCLUSION

These consistent biochemical and histopathological results suggest that, nano-ceria could be used as effective antioxidant in prophylactic protocols for management of cardiac disorders associated with oxidative stress.

Tissue deposition and toxicological effects of commercially significant rare earth oxide nanomaterials: Material and physical properties

Rare earth oxide (REO) materials are found naturally in earth's crust and at the nanoscale these REO nanoparticles exhibit unique thermal, electrical, and physicochemical properties. REO nanoparticles are widely used in different industrial sectors for ceramics, glass polishing, metallurgy, lasers, and magnets. Recently, some of these REO nanoparticles have been identified for their potential application in medicine, including therapy, imaging, and diagnostics. Concurrent research into the REO nanomaterials' toxicities has also raised concern for their environmental impacts. The correlation of REO nanoparticles mediated toxicity with their physiochemical properties can help to design nanoparticles with minimal effect on the environment and living organisms. In vitro assay revealed toxicity toward Human squamous epithelial cell line (CCL30) and Human umbilical vascular endothelial cells (HUVEC) at a concentration of 100 µM and higher. In vivo results showed, with the exception of CeO₂ and Gd₂ O₃ , most of the naoparticles did not clear or had minimum clearance (10-20%) from the system. Elevated levels of alanine transferase were seen for animals given each different nanoparticle, however the increases were not significant for CeO₂ and Dy₂ O₃ . Nephrotoxicity was only seen in case of Dy₂ O₃ and Gd₂ O₃ . Lastly, histological examination revealed presence of swollen hepatocytes which further confirms toxicity of the commercial REO nanomaterials. The in vivo toxicity is mainly due to excessive tissue deposition (70-90%) due to the commercial REO nanoparticles' poor physical properties (shape, stability, and extent of agglomeration). Therefore, optimization of nanoparticles physical properties is very important. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 904-917, 2017.

Bio-Adaption between Magnesium Alloy Stent and the Blood Vessel: A Review

Biodegradable magnesium (Mg) alloy stents are the most promising next generation of bio-absorbable stents. In this article, we summarized the progresses on the in vitro studies, animal testing and clinical trials of biodegradable Mg alloy stents in the past decades. These exciting findings led us to propose the importance of the concept "bio-adaption" between the Mg alloy stent and the local tissue microenvironment after implantation. The healing responses of stented blood vessel can be generally described in three overlapping phases: inflammation, granulation and remodeling. The ideal bio-adaption of the Mg alloy stent, once implanted into the blood vessel, needs to be a reasonable function of the time and the space/dimension. First, a very slow degeneration of mechanical support is expected in the initial four months in order to provide sufficient mechanical support to the injured vessels. Although it is still arguable whether full mechanical support in stented lesions is mandatory during the first four months after implantation, it would certainly be a safety design parameter and a benchmark for regulatory evaluations based on the fact that there is insufficient human in vivo data available, especially the vessel wall mechanical properties during the healing/remodeling phase. Second, once the Mg alloy stent being degraded, the void space will be filled by the regenerated blood vessel tissues. The degradation of the Mg alloy stent should be 100% completed with no residues, and the degradation products (e.g., ions and hydrogen) will be helpful for the tissue reconstruction of the blood vessel. Toward this target, some future research perspectives are also discussed.

Hydroxysafflor yellow A improves established monocrotaline-induced pulmonary arterial hypertension in rats

Objective

To evaluate the beneficial effects of hydroxysafflor yellow A (HSYA) on monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) in rats, and to investigate the main pathophysiological mechanism of HSYA in preventing development of MCT-induced PAH.

Methods

Four groups (control, control with HSYA treatment, MCT-exposed, and MCT-exposed with HSYA treatment) were evaluated at day 28 following MCT exposure. Haemodynamic measurements, right ventricular hypertrophy, morphometry, inflammatory cytokines and oxidant expression were assessed.

Results

HSYA significantly reduced haemodynamic changes, right ventricular hypertrophy and morphometric changes induced by exposure to MCT. HYSA also suppressed MCT-induced inflammation and oxidative stress in rat pulmonary tissue.

Conclusions

Experimental MCT-induced PAH may be reduced by HSYA treatment, and the mechanism may involve suppression of inflammation and oxidative stress.

Therapeutic Potential of Cerium Oxide Nanoparticles for the Treatment of Peritonitis Induced by Polymicrobial Insult in Sprague-Dawley Rats

OBJECTIVES

Peritonitis is a life-threatening disease that is associated with high mortality. The purpose of this study was to determine if cerium oxide nanoparticles can be used to diminish intra-abdominal infection-induced mortality and systemic inflammatory response syndrome in the laboratory rat.

DESIGN

Randomized, controlled animal study and cell culture study.

SETTING

University research laboratory.

SUBJECTS

Male Sprague-Dawley rats aged 12 weeks, RAW 246.7 macrophage cell line.

INTERVENTIONS

Intra-abdominal infection or peritonitis was induced by intraperitoneal injection of cecal material (600 mg/kg in 5% sterile dextrose water at a dosage of 5 mL/kg) obtained from healthy donors. Rats in control and peritonitis groups received 200 μL of sterile deionized water IV via the tail vein, whereas rats in cerium oxide-only group and peritonitis+cerium oxide group received cerium oxide nanoparticles (0.5 mg/kg) IV at the time of polymicrobial injection. Survival rate was monitored for 14 days, while in other experiments, animals were killed at 3 and 18 hours after induction of peritonitis for biochemical analysis.

MEASUREMENTS AND MAIN RESULTS

Administration of a single dose (0.5 mg/kg) of cerium oxide nanoparticles IV to rats in the peritonitis group significantly improved survival rates and functioned to restore core body temperature toward baseline. Treatment-induced increases in animal survivability were associated with reduced systemic and hepatic oxidative stress, diminished serum cytokines, and chemokine levels. Changes in serum inflammatory markers with treatment were accompanied by decreased monocyte and lymphocyte extravasation into the peritoneal cavity along with decreased infiltration of macrophages into liver. In the heart, treatment diminished extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase-Stat-3 signaling and attenuated endothelial expression of P-selectin and vascular cell adhesion molecule-1.

CONCLUSIONS

Cerium oxide nanoparticles attenuate the systemic inflammatory response associated with peritonitis, suggesting potential use as a novel therapeutic agent for the treatment of severe intra-abdominal infection.

Cerium oxide nanoparticles attenuate acute kidney injury induced by intra-abdominal infection in Sprague-Dawley rats

Background

Intra-abdominal infection or peritonitis is a cause for great concern due to high mortality rates. The prognosis of severe intra-abdominal infection is significantly diminished in the presence of acute kidney injury (AKI) which is often characterized by renal tubular cell death that can lead to renal failure. The purpose of the current study is to examine the therapeutic efficacy of cerium oxide (CeO₂) nanoparticles for the treatment of peritonitis-induced AKI by polymicrobial insult.

Results

A one-time administration of CeO₂ nanoparticles (0.5 mg/kg) in the absence of antibiotics or other supportive care, attenuated peritonitis-induced tubular dilatation and the loss of brush border in male Sprague–Dawley rats. These improvements in renal structure were accompanied by decreases in serum cystatin-C levels, reduced renal oxidative stress, diminished Stat-3 phosphorylation and an attenuation of caspase-3 cleavage suggesting that the nanoparticle treatment improved renal glomerular filtration rate, diminished renal inflammation and reduced renal apoptosis. Consistent with these data, further analysis demonstrated that the CeO₂ nanoparticle treatment diminished peritonitis-induced increases in serum kidney injury molecule-1 (KIM-1), osteopontin, β-2 microglobulin and vascular endothelial growth factor-A (VEGF-A) levels. In addition, the nanoparticle attenuated peritonitis-induced hyperglycemia along with increases in blood urea nitrogen (BUN), serum potassium and sodium.

Conclusion

CeO₂ nanoparticles scavenge reactive oxygen species and attenuate polymicrobial insult induced increase in inflammatory mediators and subsequent AKI. Taken together, the data indicate that CeO₂ nanoparticles may be useful as an alternative therapeutic agent or in conjunction with standard medical care for the treatment of peritonitis induced acute kidney injury.

Cerium oxide nanoparticle treatment ameliorates peritonitis-induced diaphragm dysfunction

The severe inflammation observed during sepsis is thought to cause diaphragm dysfunction, which is associated with poor patient prognosis. Cerium oxide (CeO2) nanoparticles have been posited to exhibit anti-inflammatory and antioxidative activities suggesting that these particles may be of potential use for the treatment of inflammatory disorders. To investigate this possibility, Sprague Dawley rats were randomly assigned to the following groups: sham control, CeO2 nanoparticle treatment only (0.5 mg/kg iv), sepsis, and sepsis+CeO2 nanoparticles. Sepsis was induced by the introduction of cecal material (600 mg/kg) directly into the peritoneal cavity. Nanoparticle treatment decreased sepsis-associated impairments in diaphragmatic contractile (P(o)) function (sham: 25.6±1.6 N/cm(2) vs CeO2: 23.4±0.8 N/cm(2) vs Sep: 15.9±1.0 N/cm(2) vs Sep+CeO2: 20.0±1.0 N/cm(2), P<0.05). These improvements in diaphragm contractile function were accompanied by a normalization of protein translation signaling (Akt, FOXO-1, and 4EBP1), diminished proteolysis (caspase 8 and ubiquitin levels), and decreased inflammatory signaling (Stat3 and iNOS). Histological analysis suggested that nanoparticle treatment was associated with diminished sarcolemma damage and diminished inflammatory cell infiltration. These data indicate CeO2 nanoparticles may improve diaphragmatic function in the septic laboratory rat.