Prophylactic Treatment with Cerium Oxide Nanoparticles Attenuate Hepatic Ischemia Reperfusion Injury in Sprague Dawley Rats

Antioxidant nanozymes as next-generation therapeutics to free radical-mediated inflammatory diseases: A comprehensive review

Recent developments in exploring the biological enzyme mimicking properties in nanozymes have opened a separate avenue, which provides a suitable alternative to the natural antioxidants and enzymes. Due to high and tunable catalytic activity, low cost of synthesis, easy surface modification, and good biocompatibility, nanozymes have garnered significant research interest globally. Several inorganic nanomaterials have been investigated to exhibit catalytic activities of some of the key natural enzymes, including superoxide dismutase (SOD), catalase, glutathione peroxidase, peroxidase, and oxidase, etc. These nanozymes are used for diverse biomedical applications including therapeutics, imaging, and biosensing in various cells/tissues and animal models. In particular, inflammation-related diseases are closely associated with reactive oxygen and reactive nitrogen species, and therefore effective antioxidants could be excellent therapeutics due to their free radical scavenging ability. Although biological enzymes and other artificial antioxidants could perform well in scavenging the reactive oxygen and nitrogen species, however, suffer from several drawbacks such as the requirement of strict physiological conditions for enzymatic activity, limited stability in the environment beyond their optimum pH and temperature, and high cost of synthesis, purification, and storage make then unattractive for broad-spectrum applications. Therefore, this review systematically and comprehensively presents the free radical-mediated evolution of various inflammatory diseases (inflammatory bowel disease, mammary gland fibrosis, and inflammation, acute injury of the liver and kidney, mammary fibrosis, and cerebral ischemic stroke reperfusion) and their mitigation by various antioxidant nanozymes in the biological system. The mechanism of free radical scavenging by antioxidant nanozymes under in vitro and in vivo experimental models and catalytic efficiency comparison with corresponding natural enzymes has also been presented.

Ceria-Based Therapeutic Antioxidants for Biomedical Applications

The growing interest in nanomedicine over the last 20 years has carved out a research field called "nanocatalytic therapy," where catalytic reactions mediated by nanomaterials are employed to intervene in disease-critical biomolecular processes. Among many kinds of catalytic/enzyme-mimetic nanomaterials investigated thus far, ceria nanoparticles stand out from others owing to their unique scavenging properties against biologically noxious free radicals, including reactive oxygen species (ROS) and reactive nitrogen species (RNS), by exerting enzyme mimicry and nonenzymatic activities. Much effort has been made to utilize ceria nanoparticles as self-regenerating antioxidative and anti-inflammatory agents for various kinds of diseases, given the detrimental effects of ROS and RNS therein that need alleviation. In this context, this review is intended to provide an overview as to what makes ceria nanoparticles merit attention in disease therapy. The introductory part describes the characteristics of ceria nanoparticles as an oxygen-deficient metal oxide. The pathophysiological roles of ROS and RNS are then presented, as well as their scavenging mechanisms by ceria nanoparticles. Representative examples of recent ceria-nanoparticle-based therapeutics are summarized by categorization into organ and disease types, followed by the discussion on the remaining challenges and future research directions.

The ameliorative effect of cerium oxide nanoparticles on chlorpyrifos induced hepatotoxicity in a rat model: Biochemical, molecular and immunohistochemical study

BACKGROUND

Chlorpyrifos (CPF) is a widely used insecticide that causes toxicity to living organisms through the production of free radicals. Cerium oxide nanoparticles (CeO2NPs) are a new antioxidant agent that has proved therapeutic effects. We evaluated the effect of CeO2NPs on CPF hepatotoxicity.

METHODS

Forty rats were randomized into four groups. Group I: rats received 1 ml corn oil by gastric tube once daily and 0.5 ml PBS by intra-peritoneal injection twice a week for 4 weeks. Group II: received CeO2NPs 0.5 mg/kg in PBS by i.p. injection, twice weekly for four weeks. Group III: were treated with oral administration of CPF 13.5 mg/kg in corn oil daily for 4 weeks. Group IV: received CPF as in group III, then each animal received CeO2NPs twice weekly for four weeks as in group II. Twenty-four hours after the last dose, rats were anesthetized and sera were collected for liver enzymes assessment. Afterwards, rats were sacrificed, livers were excised, the right lobe of each liver was fixed for immunohistochemical studies, and the left lobe was homogenized for oxidative profile assessment and molecular analysis.

RESULTS

CPF group showed significant increase in liver transaminases, disturbance of the oxidative profile with up-regulation of BAX expression and down-regulation in the Bcl-2, Gadd45 and NFE2L2. CPF caused severe histopathological liver damage as well as significant increase in anti-Caspase 3 and TNF immunostaining. The CeO2NPs treated group revealed significant improvement of all previous parameters.

CONCLUSION

CeO2NPs could alleviate CPF hepatoxicity through decreasing expression of the inflammatory and apoptotic proteins and increasing the activity of antioxidant enzymes.

The Impressive Anti-Inflammatory Activity of Cerium Oxide Nanoparticles: More than Redox?

Cerium oxide nanoparticles (CNPs) are biocompatible nanozymes exerting multifunctional biomimetic activities, including superoxide dismutase (SOD), catalase, glutathione peroxidase, photolyase, and phosphatase. SOD- and catalase-mimesis depend on Ce3+/Ce4+ redox switch on nanoparticle surface, which allows scavenging the most noxious reactive oxygen species in a self-regenerating, energy-free manner. As oxidative stress plays pivotal roles in the pathogenesis of inflammatory disorders, CNPs have recently attracted attention as potential anti-inflammatory agents. A careful survey of the literature reveals that CNPs, alone or as constituents of implants and scaffolds, strongly contrast chronic inflammation (including neurodegenerative and autoimmune diseases, liver steatosis, gastrointestinal disorders), infections, and trauma, thereby ameliorating/restoring organ function. By general consensus, CNPs inhibit inflammation cues while boosting the pro-resolving anti-inflammatory signaling pathways. The mechanism of CNPs' anti-inflammatory effects has hardly been investigated, being rather deductively attributed to CNP-induced ROS scavenging. However, CNPs are multi-functional nanozymes that exert additional bioactivities independent from the Ce3+/Ce4+ redox switch, such as phosphatase activity, which could conceivably mediate some of the anti-inflammatory effects reported, suggesting that CNPs fight inflammation via pleiotropic actions. Since CNP anti-inflammatory activity is potentially a pharmacological breakthrough, it is important to precisely attribute the described effects to one or another of their nanozyme functions, thus achieving therapeutic credibility.

Structural and functional insights in polysaccharides coated cerium oxide nanoparticles and their potential biomedical applications: A review

Cerium oxide nanoparticles have now significant presence in biomedical fields due to their wide applications; however, challenges regarding their safety and biocompatibility persist. Polysaccharides based biopolymers have inherent hydroxyl and carboxyl groups, enabling them to govern the surface functionalization of cerium oxide nanoparticles, hence their chemical and physical characteristics. Because of this, polysaccharides such as dextran, alginate, pullulan, chitosan, polylactic acid, starch, and pectin are practical substitutes for the conventional coatings used to synthesize cerium oxide nanoparticles. This review discusses the effect of biopolymer coatings on the properties of cerium oxide nanoparticles, such as size, stability, aggregation, and biocompatibility. Additionally, it also summarises various biomedical applications of polysaccharides coated cerium oxide nanoparticles, such as in bone tissue regeneration, liver inflammation, wound healing, and antibacterial and anticancer activities. Biocompatible cerium oxide nanoparticles will surely improve their applications in the biomedical field.

Effects of cerium oxide (CeO2) on liver tissue in liver ischemia-reperfusion injury in rats undergoing desflurane anesthesia

INTRODUCTION

During liver surgery and transplantation, periods of partial or total vascular occlusion are inevitable and result in ischemia-reperfusion injury (IRI). Nanomedicine uses the latest technology, which has emerged with interdisciplinary effects, such as biomedical sciences, physics, and engineering, to protect and improve human health. Interdisciplinary research has brought along the introduction of antioxidant nanoparticles as potential therapeutics. The goal of this study was to investigate the effects of cerium oxide (CeO₂) administration and desflurane anesthesia on liver tissue in liver IR injury.

MATERIAL AND METHODS

Thirty rats were randomly divided into five groups: control (C), ischemia-reperfusion (IR), IR-desflurane (IRD), cerium oxide-ischemia reperfusion (CeO₂-IR), and cerium oxide-ischemia reperfusion-desflurane (CeO₂-IRD). In the IR, IRD, and CeO₂-IRD groups, hepatic ischemia was induced after the porta hepatis was clamped for 120 min, followed by 120 min of reperfusion. Intraperitoneal 0.5 mg/kg CeO₂ was administered to the CeO₂ groups 30 min before ischemia. Desflurane (6%) was administered to the IRD and CeO₂-IRD groups during IR. All groups were sacrificed under anesthesia. Liver tissue samples were examined under a light microscope by staining with hematoxylin-eosin (H&E). Malondialdehyde (MDA) levels, catalase (CAT), glutathione-s-transferase (GST), and arylesterase (ARE) enzyme activities were measured in the tissue samples.

RESULTS

The IR group had considerably more hydropic degeneration, sinusoidal dilatation, and parenchymal mononuclear cell infiltration than the IRD, CeO₂-IR, and CeO₂-IRD groups. Catalase and GST enzyme activity were significantly higher in the CeO₂-IR group than in the IR group. The MDA levels were found to be significantly lower in the IRD, CeO₂-IR, and CeO₂-IRD groups than in the IR group.

CONCLUSION

Intraperitoneal CeO₂ with desflurane reduced oxidative stress and corrected liver damage.

Structure design mechanisms and inflammatory disease applications of nanozymes

Nanozymes are artificial enzymes with high catalytic activity, low cost, and good biocompatibility, and have received ever-increasing attention in recent years. Various inorganic and organic nanoparticles have been found to exhibit enzyme-like activities and are used as nanozymes for diverse biomedical applications ranging from tumor imaging and therapeutics to detection. However, their further clinical applications are hindered by the potential toxicity and long-term retention of nanomaterials in vivo. Clarifying the catalytic mechanism of nanozymes and identifying the key factors responsible for their behavior can guide the design of nanozyme structure, enlighten the ways to improve their enzyme-like activities, and minimize the dosage of nanozymes, leading to reduced toxicity to the human body for a real biomedical application prospect. In particular, inflammation occurring in numerous diseases is closely related to reactive oxygen species, and the active oxygen scavenging ability of nanozymes potentially exerts excellent therapeutic effects on inflammatory diseases. In this review, we systematically summarize the structure-activity relationship of nanozymes, including regulation strategies for size and morphology, surface structure, and composition. Based on the structure-activity mechanisms, a series of chemically designed nanozymes developed to target various inflammatory diseases are briefly summarized.

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.

Comparison of biodistribution of cerium oxide nanoparticles after repeated oral administration by gavage or snack in Sprague Dawley rats

The rate of translocation of ingested nanoparticles (NPs) and how the uptake is affected by a food matrix are key aspects of health risk assessment. In this study, female Sprague Dawley rats (N = 4/group) received 0, 1.4, or 13 mg of cerium oxide (CeO₂ NM-212) NPs/rat/day by gavage or in a chocolate spread snack 5 days/week for 1 or 2 weeks followed by 2 weeks of recovery. A dose and time-dependent uptake in the liver and spleen of 0.1-0.3 and 0.004-0.005 parts per million (ng/mg) of the total administered dose was found, respectively. There was no statistically significant difference in cerium concentration in the liver or spleen after gavage compared to snack dosing. Microscopy revealed indications of necrotic changes in the liver and decreased cellularity in white pulp in the spleen. The snack provided precise administration and a more human-relevant exposure of NPs and could improve animal welfare as alternative to gavage.

Anti-inflammatory effects of oral and intraperitoneal administration of cerium oxide nanoparticles on experimental hepatic ischemia-reperfusion injury

Objectives

Hepatic ischemia-reperfusion (IR) injury occurs in liver surgery, resection, and transplantation. Reactive oxygen species (ROS) produced following IR starts the cascade of cell damage, necrosis/apoptosis, and proinflammatory responses by activating intracellular signaling cascade to drive hepatocellular damage. Cerium oxide nanoparticles (CONPs) act as anti-inflammatory and antioxidant agents. Thus, we evaluated the protective effects of oral (o.g.) and intraperitoneal (i.p.) administration of CONPs on hepatic IR injury.

Material and Methods

Mice were randomly divided into five groups: control, sham, IR protocol, CONP+IR (i.p.), and CONP+IR (o.g.). Mouse hepatic IR protocol was applied to the animals in the IR group. CONPs (300 μg/kg) were administered 24 hours before IR protocol. Blood and tissue samples were taken after the reperfusion period.

Results

Hepatic IR injury markedly increased enzyme activities, tissue lipid peroxidation, myeloperoxidase (MPO), xanthine oxidase (XO), nitrite oxide (NO), and tissue nuclear factor kappa-B (NF-κB) p65 levels, plasma pro-inflammatory cytokines, chemokines, and adhesion molecules while decreasing antioxidant markers and caused pathological changes in hepatic tissue. The expression of tumor necrosis factor alpha (TNF-α), matrix metalloproteinase 2 (MMP-2), and 9 increased, and tissue inhibitor matrix metalloproteinase 1 (TIMP-1) expression decreased in the IR group. Pretreatment with CONPs o.g. and i.p. 24 hours before hepatic ischemia improved the biochemical parameters above and alleviated the histopathological findings.

Conclusion

Results of the present study demonstrate a significant reduction in liver degeneration by administering CONPs via i.p. and o.g. route in an experimental liver IR model, suggesting that CONPs have the extensive potential to prevent hepatic IR injury.

Effect of Cerium Oxide on Kidney and Lung Tissue in Rats with Testicular Torsion/Detorsion

Introduction

Testicular torsion is a surgical emergency that results in testicular ischemia as a result of rotation of the spermatic cord around itself. Oxidative damage occurs in the testis and distant organs with the overproduction of free radicals and overexpression of proinflammatory cytokines by reperfusion after surgery. In this study, we aimed to investigate the effects of cerium oxide (CeO₂), an antioxidant nanoparticle, on lung and kidney tissues in testicular torsion/detorsion (T/D) in rats.

Materials and Methods

After ethics committee approval, 24 rats were equally (randomly) divided into 4 groups. Left inguinoscrotal incision was performed in the control (C) group. In group CeO₂, 0.5 mg/kg CeO₂ was given intraperitoneally 30 minutes before inguinoscrotal incision. In group T/D, unilateral testicular T/D was achieved by performing an inguinoscrotal incision and rotating the left testis 720° clockwise, remaining ischemic for 120 minutes, followed by 120 minutes of reperfusion. In group CeO₂-T/D, 0.5 mg/kg CeO₂ was given intraperitoneally 30 minutes before testicular T/D. At the end of the experiment, lung and kidney tissues were removed for histopathological and biochemical examinations.

Results

Glomerular vacuolization (GV), tubular dilatation (TD), tubular cell degeneration and necrosis (TCDN), leukocyte infiltration (LI), and tubular cell spillage (TCS) in renal tissue were significantly different between groups (p = 0.012, p = 0.049, p < 0.003, p = 0.046, and p = 0.049, respectively). GV and TCDN were significantly decreased in group CeO₂-T/D compared to group T/D (p = 0.042 and p = 0.029, respectively). Lung tissue neutrophil infiltration, alveolar thickening, and total lung injury score (TLIS) were significantly different between groups (p = 0.006, p = 0.001, and p = 0.002, respectively). Neutrophil infiltration and TLIS were significantly decreased in group CeO₂-T/D compared to group T/D (p = 0.013 and p = 0.033, respectively). Lung and kidney tissue oxidative stress parameters were significantly different between groups (p < 0.05). Renal tissue glutathione-s-transferase (GST), catalase (CAT), and paraoxonase (PON) activities were significantly higher, and malondialdehyde (MDA) levels were significantly lower in group CeO₂-T/D than in group T/D (p = 0.049, p = 0.012, p < 0.001, and p = 0.004, respectively). GST and PON activities were higher, and MDA levels were lower in group CeO₂-T/D than in group T/D in the lung tissue (p = 0.002, p < 0.001, and p = 0.008, respectively). Discussion. In our study, cerium oxide was shown to reduce histopathological and oxidative damage in the lung and kidney tissue in a rat testis torsion/detorsion model.

Attenuation of hepatic ischemia‑reperfusion injury by adipose stem cell‑derived exosome treatment via ERK1/2 and GSK‑3β signaling pathways

Exosomes are an emerging therapeutic tool for the treatment of tissue injuries. In the present study, the protective effect of isolated exosomes from adipose‑derived stem cells (ADSCs‑exo) against hepatic ischemia‑reperfusion (I/R) injury was explored. Hepatic I/R injury was achieved by inducing ischemia for 60 min followed by reperfusion for 2 and 6 h. Pre‑treatment with ADSCs‑exo revealed a significant reduction in necrosis and apoptosis in liver tissue induced by I/R injury. Hypoxic oxidative stress was managed by exosome‑mediated reduced reactive oxygen species and increased superoxide dismutase that in turn protected mitochondrial damage and apoptosis. Reduction in inflammatory mediators such as IL‑1β and TNF‑α was also observed and protection of hepatocytes from I/R injury was evidenced by a significant decrease in biochemical markers of liver damage (alanine transaminase, aspartate transaminase and lactate dehydrogenase). Exosomal prostaglandin E2 (PGE2)‑mediated ERK1/2 and GSK‑3β phosphorylation were revealed to increase Bcl‑2 and decrease Bax expression with mitochondrial permeability transition pore‑inhibition which may be considered a prime mechanism of exosome‑mediated hepatoprotection. In conclusion, our results indicated that ADSCs‑exo pre‑treatment is effective in protecting liver I/R injury.

The use of cerium oxide nanoparticles in liver disorders: A double-sided coin?

Being recognized as the first antioxidant nanoparticles (NPs) proposed for medicine, cerium oxide nanoparticles (CeO₂ NPs) have recently gained tremendous attention for their vast biomedical applications. Nevertheless, inconsistent reports of either medical benefits or toxicity have created an atmosphere of uncertainty hindering their clinical utilization. Like other nanoparticles advocated as a promising protective/therapeutic option, CeO₂ NPs are sometimes questioned as a health threat. As CeO₂ NPs tend to accumulate in the liver after intravenous injection, liver is known to represent the key tissue to test for their therapeutic/toxicological effects. However, more research evidence is still needed before any conclusions can be elicited about the mechanisms by which CeO₂ NPs could be harmful or protective/therapeutic to the liver tissue. A proper understanding of such discrepancies is warranted to plan for further modifications to mitigate any side effects. Therefore, in this MiniReview, we tried to demonstrate the two sides of the same coin, CeO₂ NPs, within the liver context. As well, we highlighted a few promising strategies by which the negatives of CeO₂ NPs could be diminished while enhancing all the positives.

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.

The therapeutic effect of cerium oxide nanoparticle on ischaemia/reperfusion injury in rat testis

Testicular torsion is a dangerous urogenital disorder which is caused by twisting of spermatic cord, and unless immediate treatments happen at a proper time, oxidative stress, occurred during ischaemia reperfusion, finally leads to irreversible disintegration of testicular tissue. One of the first preventive lines is to administrate antioxidant factors. In the present study, we investigate the therapeutic effect of cerium oxide nanoparticle on the injury. We divided 45 rats into nine groups, subjected eight groups to testicular torsion-detorsion, injected different doses of cerium oxide nanoparticle into the peritoneum of six groups and analysed all the groups regarding spermatogenetic indices including sperm count, sperm viability and Johnson mean. Our results showed that cerium oxide nanoparticle can alleviate oxidative stress in testis, and this alleviation promotes the reproductive indices as the concentration of cerium oxide nanoparticles increases. The catalase-mimetic and superoxide dismutase-mimetic activities of cerium oxide nanoparticle are the most probable theories to explain the antioxidant effect of the nanoparticle.

Extended criteria grafts and emerging therapeutics strategy in liver transplantation. The unstable balance between damage and repair

Due to increasing demand for donor organs, "extended criteria" donors are increasingly considered for liver transplantation, including elderly donors and donors after cardiac death. The grafts of this subgroup of donors share a major risk to develop significant features of ischemia reperfusion injury, that may eventually lead to graft failure. Ex-situ machine perfusion technology has gained much interest in liver transplantation, because represents both a useful tool for improving graft quality before transplantation and a platform for the delivery of therapeutics directly to the organ. In this review, we survey ongoing clinical evidences supporting the use of elderly and DCD donors in liver transplantation, and the underlying mechanistic aspects of liver aging and ischemia reperfusion injury that influence graft quality and transplant outcome. Finally, we highlight evidences in the field of new therapeutics to test in MP in the context of recent findings of basic and translational research.

Perioperative Perfusion of Allografts with Anti-Human T-lymphocyte Globulin Does Not Improve Outcome Post Liver Transplantation-A Randomized Placebo-Controlled Trial

Due to the lack of suitable organs transplant surgeons have to accept unfavorable extended criteria donor (ECD) organs. Recently, we demonstrated that the perfusion of kidney organs with anti-human T-lymphocyte globulin (ATLG) prior to transplantation ameliorates ischemia-reperfusion injury (IRI). Here, we report on the results of perioperative ATLG perfusion in a randomized, single-blinded, placebo-controlled, feasibility trial (RCT) involving 30 liver recipients (LTx). Organs were randomly assigned for perfusion with ATLG/Grafalon^® (AP) (n = 16) or saline only (control perfusion = CP) (n = 14) prior to implantation. The primary endpoint was defined as graft function reflected by aspartate transaminase (AST) values at day 7 post-transplantation (post-tx). With respect to the primary endpoint, no significant differences in AST levels were shown in the intervention group at day 7 (AP: 53.0 ± 21.3 mg/dL, CP: 59.7 ± 59.2 mg/dL, p = 0.686). Similarly, exploratory analysis of secondary clinical outcomes (e.g., patient survival) and treatment-specific adverse events revealed no differences between the study groups. Among liver transplant recipients, pre-operative organ perfusion with ATLG did not improve short-term outcomes, compared to those who received placebo perfusion. However, ATLG perfusion of liver grafts was proven to be a safe procedure without the occurrence of relevant adverse events.

Nanotheranostics for the Management of Hepatic Ischemia-Reperfusion Injury

Hepatic ischemia-reperfusion injury (IRI), in which an insufficient oxygen supply followed by reperfusion leads to an inflammatory network and oxidative stress in disease tissue to cause cell death, always occurs after liver transplantations and sections. Although pharmacological treatments favorably prevent or protect the liver against experimental IRI, there have been few successes in clinical applications for patient benefits because of the incomprehension of complicated IRI-induced signaling events as well as short blood circulation time, poor solubility, and severe side reactions of most antioxidants and anti-inflammatory drugs. Nanomaterials can achieve targeted delivery and controllable release of contrast agents and therapeutic drugs in desired hepatic IRI regions for enhanced imaging sensitivity and improved therapeutic effects, emerging as novel alternative approaches for hepatic IRI diagnosis and therapy. In this review, the application of nanotechnology is summarized in the management of hepatic IRI, including nanomaterial-assisted hepatic IRI diagnosis, nanoparticulate systems-mediated remission of reactive oxygen species-induced tissue injury, and nanoparticle-based targeted drug delivery systems for the alleviation of IRI-related inflammation. The current challenges and future perspectives of these nanoenabled strategies for hepatic IRI treatment are also discussed.

Cerium Oxide Nanoparticles: A New Therapeutic Tool in Liver Diseases

Oxidative stress induced by the overproduction of free radicals or reactive oxygen species (ROS) has been considered as a key pathogenic mechanism contributing to the initiation and progression of injury in liver diseases. Consequently, during the last few years antioxidant substances, such as superoxide dismutase (SOD), resveratrol, colchicine, eugenol, and vitamins E and C have received increasing interest as potential therapeutic agents in chronic liver diseases. These substances have demonstrated their efficacy in equilibrating hepatic ROS metabolism and thereby improving liver functionality. However, many of these agents have not successfully passed the scrutiny of clinical trials for the prevention and treatment of various diseases, mainly due to their unspecificity and consequent uncontrolled side effects, since a minimal level of ROS is needed for normal functioning. Recently, cerium oxide nanoparticles (CeO₂NPs) have emerged as a new powerful antioxidant agent with therapeutic properties in experimental liver disease. CeO₂NPs have been reported to act as a ROS and reactive nitrogen species (RNS) scavenger and to have multi-enzyme mimetic activity, including SOD activity (deprotionation of superoxide anion into oxygen and hydrogen peroxide), catalase activity (conversion of hydrogen peroxide into oxygen and water), and peroxidase activity (reducing hydrogen peroxide into hydroxyl radicals). Consequently, the beneficial effects of CeO₂NPs treatment have been reported in many different medical fields other than hepatology, including neurology, ophthalmology, cardiology, and oncology. Unlike other antioxidants, CeO₂NPs are only active at pathogenic levels of ROS, being inert and innocuous in healthy cells. In the current article, we review the potential of CeO₂NPs in several experimental models of liver disease and their safety as a therapeutic agent in humans as well.

Drug delivery nanosystems targeted to hepatic ischemia and reperfusion injury

Hepatic ischemia and reperfusion injury (IRI) is an acute inflammatory process that results from surgical interventions, such as liver resection surgery or transplantation, or hemorrhagic shock. This pathology has become a severe clinical issue, due to the increasing incidence of hepatic cancer and the high number of liver transplants. So far, an effective treatment has not been implemented in the clinic. Despite its importance, hepatic IRI has not attracted much interest as an inflammatory disease, and only a few reviews addressed it from a therapeutic perspective with drug delivery nanosystems. In the last decades, drug delivery nanosystems have proved to be a major asset in therapy because of their ability to optimize drug delivery, either by passive or active targeting. Passive targeting is achieved through the enhanced permeability and retention (EPR) effect, a main feature in inflammation that allows the accumulation of the nanocarriers in inflammation sites, enabling a higher efficacy of treatment than conventional therapies. These systems also can be actively targeted to specific compounds, such as inflammatory markers and overexpressed receptors in immune system intermediaries, allowing an even more specialized therapy that have already showed encouraging results. In this manuscript, we review drug delivery nanosystems designed for hepatic IRI treatment, addressing their current state in clinical trials, discussing the main hurdles that hinder their successful translation to the market and providing some suggestions that could potentially advance their clinical translation.

Ischemia Reperfusion Injury: Opportunities for Nanoparticles

Ischemia reperfusion (IR)-induced oxidative stress, accompanied by inflammatory responses, contributes to morbidity and mortality in numerous diseases such as acute coronary syndrome, stroke, organ transplantation, and limb injury. Ischemia results in profound hypoxia and tissue dysfunction, whereas subsequent reperfusion further aggravates ischemic tissue damage through inducing cell death and activating inflammatory responses. In this review, we highlight recent studies of therapeutic strategies against IR injury. Furthermore, nanotechnology offers significant improvements in this area. Hence, we also review recent advances in nanomedicines for IR therapy, suggesting them as potent and promising strategies to improve drug delivery to IR-injured tissues and achieve protective effects.

The Effect of Cerium Oxide on Lung Tissue in Lower Extremity Ischemia Reperfusion Injury in Sevoflurane Administered Rats

Introduction

We aimed to investigate the effects of cerium oxide, applied before the sevoflurane anesthesia, on lung tissue in rats with lower extremity ischemia-reperfusion (IR).

Materials and Methods

A total of 30 rats were randomly divided into five groups as; control (C), IR, cerium oxide-IR (CO-IR), IR-sevoflurane (IRS), and cerium oxide-IR-sevoflurane (CO-IRS). In the CO-IR group, 30 minutes after the injection of cerium oxide (0.5 mg/kg, intraperitoneal (i.p)), an atraumatic microvascular clamp was placed on the infrarenal abdominal aorta for 120 minutes. Then, the clamp was removed and reperfused for 120 minutes. Sevoflurane was applied in 100% oxygen at a rate of 2.3% at 4 L/min during IR. The blood samples were taken for biochemical analysis and the lung tissue samples were taken for histological analysis.

Results

Neutrophil infiltration/aggregation was significantly higher in the IR group than in the C and CO-IRS groups. The alveolar wall thickness and total lung injury scores were significantly higher in the IR group than in the C, IRS, CO-IR and CO-IRS groups.

Discussion

We determined that the administration of 0.5 mg/kg dose of cerium oxide with sevoflurane reduces the oxidative stress and corrects IR-related damage in lung tissue. Our results show that the administration of cerium oxide before IR and the administration of sevoflurane during IR have a protective effect in rats.

An overview on recent in vivo biological application of cerium oxide nanoparticles

Cerium oxide nanoparticles (CNPs) possess a great potential as therapeutic agents due to their ability to self-regenerate by reversibly switching between two valences +3 and +4. This article reviews recent articles dealing with in vivo studies of CNPs towards Alzheimer's disease, obesity, liver inflammation, cancer, sepsis, amyotrophic lateral sclerosis, acute kidney injury, radiation-induced tissue damage, hepatic ischemia reperfusion injury, retinal diseases and constipation. In vivo anti-cancer studies revealed the effectiveness of CNPs to reduce tumor growth and angiogenesis in melanoma, ovarian, breast and retinoblastoma cancer cell-induced mice, with their conjugation with folic acid, doxorubicin, CPM, or CXC receptor-4 antagonist ligand eliciting higher efficiency. After conjugation with triphenylphosphonium or magnetite nanoparticles, CNPs were shown to combat Alzheimer's disease by reducing amyloid-β, glial fibrillary acidic protein, inflammatory and oxidative stress markers in mice. By improving muscle function and longevity, the citrate/EDTA-stabilized CNPs could ameliorate amyotrophic lateral sclerosis. Also, they could effectively reduce obesity in mice by scavenging ROS and reducing adipogenesis, triglyceride synthesis, GAPDH enzyme activity, leptin and insulin levels. In CCl4-induced rats, stress signaling pathways due to inflammatory cytokines, liver enzymes, oxidative and endoplasmic reticulum messengers could be attenuated by CNPs. Commercial CNPs showed protective effects on rats with hepatic ischemia reperfusion and peritonitis-induced hepatic/cardiac injuries by decreasing oxidative stress and hepatic/cardiac inflammation. The same CNPs could improve kidney function by diminishing renal superoxide, hyperglycemia and tubular damage in peritonitis-induced acute kidney injury in rats. Radiation-induced lung and testicular tissue damage could be alleviated in mice, with the former showing improvement in pulmonary distress and bronchoconstriction and the latter exhibiting restoration in spermatogenesis rate and spermatid/spermatocyte number. Through enhancement of gastrointestinal motility, the CNPs could alleviate constipation in both young and old rats. They could also protect rat from light-induced retinal damage by slowing down neurodegenerative process and microglial activation.

Reactive Oxygen Species (ROS)-Responsive Nanomedicine for Solving Ischemia-Reperfusion Injury

Ischemia-reperfusion injury (IRI) is a severe condition for most organs, which could occur in various tissues including brain, heart, liver, and kidney, etc. As one of the major hazards, reactive oxygen species (ROS) is excessively generated after IRI, which causes severe damage inside tissues and further induces the following injury via inflammatory response. However, current medical strategies could not thoroughly diagnose and prevent this disease, eventually leading to severe sequelae by missing the best time point for therapy. In the past decade, various nanoparticles that could selectively respond to ROS have been developed and applied in IRI. These advanced nanomedicines have shown efficient performance in detecting and treating a series of IRI (e.g., acute kidney injury, acute liver injury, and ischemic stroke, etc.), which are well-summarized in the current review. In addition, the nano-platforms (e.g., anti-IL-6 antibody, rapamycin, and hydrogen sulfide delivering nanoparticles, etc.) for preventing IRI during organ transplantation have also been included. Moreover, the development and challenges of ROS-responsive nanomedicine are systematically discussed for guiding the future direction.

Cerium Oxide Nanoparticles: Advances in Biodistribution, Toxicity, and Preclinical Exploration

Antioxidant nanoparticles have recently gained tremendous attention for their enormous potential in biomedicine. However, discrepant reports of either medical benefits or toxicity, and lack of reproducibility of many studies, generate uncertainties delaying their effective implementation. Herein, the case of cerium oxide is considered, a well-known catalyst in the petrochemistry industry and one of the first antioxidant nanoparticles proposed for medicine. Like other nanoparticles, it is now described as a promising therapeutic alternative, now as threatening to health. Sources of these discrepancies and how this analysis helps to overcome contradictions found for other nanoparticles are summarized and discussed. For the context of this analysis, what has been reported in the liver is reviewed, where many diseases are related to oxidative stress. Since well-dispersed nanoparticles passively accumulate in liver, it represents a major testing field for the study of new nanomedicines and their clinical translation. Even more, many contradictory works have reported in liver either cerium-oxide-associated toxicity or protection against oxidative stress and inflammation. Based on this, finally, the intention is to propose solutions to design improved nanoparticles that will work more precisely in medicine and safely in society.

Diesel exhaust particle and dust mite induced airway inflammation is modified by cerium dioxide nanoparticles

Cerium dioxide nanoparticles (CeO₂NPs) have been used as diesel fuel-borne catalysts for improved efficiency and pollutant emissions. Concerns that such material may influence diesel exhaust particle (DEP) effects within the lung upon inhalation, prompted us to examine particle responses in mice in the presence and absence of the common allergen house dust mite (HDM). Repeated intranasal instillation of combined HDM and DEP increased airway mucin, eosinophils, lymphocytes, IL-5, IL-13, IL-17A and plasma IgE, which were further increased with CeO₂NPs co-exposure. A single co-exposure of CeO₂NPs and DEP after repeated HDM exposure increased macrophage and IL-17A levels above DEP induced levels. CeO₂NPs exposure in the absence of HDM also resulted in increased levels of plasma IgE and airway mucin staining, changes not observed with repeated DEP exposure alone. These observations indicate that CeO₂NPs can modify exhaust particulate and allergen induced inflammatory events in the lung with the potential to influence conditions such as allergic airway disease.

Ceria Nanoparticles Meet Hepatic Ischemia-Reperfusion Injury: The Perfect Imperfection

The mononuclear phagocyte system (MPS, e.g., liver, spleen) is often treated as a "blackbox" by nanoresearchers in translating nanomedicines. Often, most of the injected nanomaterials are sequestered by the MPS, preventing their delivery to the desired disease areas. Here, this imperfection is exploited by applying nano-antioxidants with preferential liver uptake to directly prevent hepatic ischemia-reperfusion injury (IRI), which is a reactive oxygen species (ROS)-related disease. Ceria nanoparticles (NPs) are selected as a representative nano-antioxidant and the detailed mechanism of preventing IRI is investigated. It is found that ceria NPs effectively alleviate the clinical symptoms of hepatic IRI by scavenging ROS, inhibiting activation of Kupffer cells and monocyte/macrophage cells. The released pro-inflammatory cytokines are then significantly reduced and the recruitment and infiltration of neutrophils are minimized, which suppress subsequent inflammatory reaction involved in the liver. The protective effect of nano-antioxidants against hepatic IRI in living animals and the revealed mechanism herein suggests their future use for the treatment of hepatic IRI in the clinic.

Simulated biological fluid exposure changes nanoceria's surface properties but not its biological response

Nanoscale cerium dioxide (nanoceria) has industrial applications, capitalizing on its catalytic, abrasive, and energy storage properties. It auto-catalytically cycles between Ce³⁺ and Ce⁴⁺, giving it pro-and anti-oxidative properties. The latter mediates beneficial effects in models of diseases that have oxidative stress/inflammation components. Engineered nanoparticles become coated after body fluid exposure, creating a corona, which can greatly influence their fate and effects. Very little has been reported about nanoceria surface changes and biological effects after pulmonary or gastrointestinal fluid exposure. The study objective was to address the hypothesis that simulated biological fluid (SBF) exposure changes nanoceria's surface properties and biological activity. This was investigated by measuring the physicochemical properties of nanoceria with a citric acid coating (size; morphology; crystal structure; surface elemental composition, charge, and functional groups; and weight) before and after exposure to simulated lung, gastric, and intestinal fluids. SBF-exposed nanoceria biological effect was assessed as A549 or Caco-2 cell resazurin metabolism and mitochondrial oxygen consumption rate. SBF exposure resulted in loss or overcoating of nanoceria's surface citrate, greater nanoceria agglomeration, deposition of some SBF components on nanoceria's surface, and small changes in its zeta potential. The engineered nanoceria and SBF-exposed nanoceria produced no statistically significant changes in cell viability or cellular oxygen consumption rates.

Graft Pre-conditioning by Peri-Operative Perfusion of Kidney Allografts With Rabbit Anti-human T-lymphocyte Globulin Results in Improved Kidney Graft Function in the Early Post-transplantation Period-a Prospective, Randomized Placebo-Controlled Trial

Introduction: Although prone to a higher degree of ischemia reperfusion injury (IRI), the use of extended criteria donor (ECD) organs has become reality in transplantation. We therefore postulated that peri-operative perfusion of renal transplants with anti-human T-lymphocyte globulin (ATLG) ameliorates IRI and results in improved graft function.

Methods: We performed a randomized, single-blinded, placebo-controlled trial involving 50 kidneys (KTx). Prior to implantation organs were perfused and incubated with ATLG (AP) (n = 24 kidney). Control organs (CP) were perfused with saline only (n = 26 kidney). Primary endpoint was defined as graft function reflected by serum creatinine at day 7 post transplantation (post-tx).

Results: AP-KTx recipients illustrated significantly better graft function at day 7 post-tx as reflected by lower creatinine levels, whereas no treatment effect was observed after 12 months surveillance. During the early hospitalization phase, 16 of the 26 CP-KTx patients required dialysis during the first 7 days post-tx, whereas only 10 of the 24 AP-KTx patients underwent dialysis. No treatment-specific differences were detected for various lymphocytes subsets in the peripheral blood of patients. Additionally, mRNA analysis of 0-h biopsies post incubation with ATLG revealed no changes of intragraft inflammatory expression patterns between AP and CP organs.

Conclusion: We here present the first clinical study on peri-operative organ perfusion with ATLG illustrating improved graft function in the early period post kidney transplantation.

Clinical Trial Registration:www.ClinicalTrials.gov, NCT03377283

Cerium Oxide Nanoparticles: A Brief Review of Their Synthesis Methods and Biomedical Applications

Cerium oxide nanoparticles (CeNPs) exhibit antioxidant properties both in vitro and in vivo. This is due to the self-regeneration of their surface, which is based on redox-cycling between 3+ and 4+ states for cerium, in response to their immediate environment. Additionally, oxygen vacancies in the lattice structure allow for alternating between CeO₂ and CeO2-x during redox reactions. Research to identify and characterize the biomedical applications of CeNPs has been heavily focused on investigating their use in treating diseases that are characterized by higher levels of reactive oxygen species (ROS). Although the bio-mimetic activities of CeNPs have been extensively studied in vitro, in vivo interactions and associated protein corona formation are not well understood. This review describes: (1) the methods of synthesis for CeNPs, including the recent green synthesis methods that offer enhanced biocompatibility and a need for establishing a reference CeNP material for consistency across studies; (2) their enzyme-mimetic activities, with a focus on their antioxidant activities; and, (3) recent experimental evidence that demonstrates their ROS scavenging abilities and their potential use in personalized medicine.

Cerium dioxide nanoparticles exacerbate house dust mite induced type II airway inflammation

Background

Nanomaterial inhalation represents a potential hazard for respiratory conditions such as asthma. Cerium dioxide nanoparticles (CeO₂NPs) have the ability to modify disease outcome but have not been investigated for their effect on models of asthma and inflammatory lung disease. The aim of this study was to examine the impact of CeO₂NPs in a house dust mite (HDM) induced murine model of asthma.

Results

Repeated intranasal instillation of CeO₂NPs in the presence of HDM caused the induction of a type II inflammatory response, characterised by increased bronchoalveolar lavage eosinophils, mast cells, total plasma IgE and goblet cell metaplasia. This was accompanied by increases in IL-4, CCL11 and MCPT1 gene expression together with increases in the mucin and inflammatory regulators CLCA1 and SLC26A4. CLCA1 and SLC26A4 were also induced by CeO₂NPs + HDM co-exposure in air liquid interface cultures of human primary bronchial epithelial cells. HDM induced airway hyperresponsiveness and airway remodelling in mice were not altered with CeO₂NPs co-exposure. Repeated HMD instillations followed by a single exposure to CeO₂NPs failed to produce changes in type II inflammatory endpoints but did result in alterations in the neutrophil marker CD177. Treatment of mice with CeO₂NPs in the absence of HDM did not have any significant effects. RNA-SEQ was used to explore early effects 24 h after single treatment exposures. Changes in SAA3 expression paralleled increased neutrophil BAL levels, while no changes in eosinophil or lymphocyte levels were observed. HDM resulted in a strong induction of type I interferon and IRF3 dependent gene expression, which was inhibited with CeO₂NPs co-exposure. Changes in the expression of genes including CCL20, CXCL10, NLRC5, IRF7 and CLEC10A suggest regulation of dendritic cells, macrophage functionality and IRF3 modulation as key early events in how CeO₂NPs may guide pulmonary responses to HDM towards type II inflammation.

Conclusions

CeO₂NPs were observed to modulate the murine pulmonary response to house dust mite allergen exposure towards a type II inflammatory environment. As this type of response is present within asthmatic endotypes this finding may have implications for how occupational or incidental exposure to CeO₂NPs should be considered for those susceptible to disease.

Electronic supplementary material

The online version of this article (10.1186/s12989-018-0261-5) contains supplementary material, which is available to authorized users.

Unintended effects of drug carriers: Big issues of small particles

Humoral and cellular host defense mechanisms including diverse phagocytes, leukocytes, and immune cells have evolved over millions of years to protect the body from microbes and other external and internal threats. These policing forces recognize engineered sub-micron drug delivery systems (DDS) as such a threat, and react accordingly. This leads to impediment of the therapeutic action, extensively studied and discussed in the literature. Here, we focus on side effects of DDS interactions with host defenses. We argue that for nanomedicine to reach its clinical potential, the field must redouble its efforts in understanding the interaction between drug delivery systems and the host defenses, so that we can engineer safer interventions with the greatest potential for clinical success.