Nanoceria protects from alterations in oxidative metabolism and calcium overloads induced by TNFα and cycloheximide in U937 cells: pharmacological potential of nanoparticles

Oxidative Effects in Early Stages of Embryo Development Due to Alcohol Consumption

Alcohol, a widely consumed drug, exerts significant toxic effects on the human organism. This review focuses on its impact during fetal development, when it leads to a spectrum of disorders collectively termed Fetal Alcohol Spectrum Disorders (FASD). Children afflicted by FASD exhibit distinct clinical manifestations, including facial dysmorphism, delayed growth, and neurological and behavioral disorders. These behavioral issues encompass diminished intellectual capacity, memory impairment, and heightened impulsiveness. While the precise mechanisms underlying alcohol-induced fetal damage remain incompletely understood, research indicates a pivotal role for reactive oxygen species (ROS) that are released during alcohol metabolism, inciting inflammation at the cerebral level. Ethanol metabolism amplifies the generation of oxidant molecules, inducing through alterations in enzymatic and non-enzymatic systems responsible for cellular homeostasis. Alcohol consumption disrupts endogenous enzyme activity and fosters lipid peroxidation in consumers, potentially affecting the developing fetus. Addressing this concern, administration of metformin during the prenatal period, corresponding to the third trimester of human pregnancy, emerges as a potential therapeutic intervention for mitigating FASD. This proposed approach holds promise for ameliorating the adverse effects of alcohol exposure on fetal development and warrants further investigation.

Gallic acid and/or cerium oxide nanoparticles synthesized by gamma-irradiation protect cisplatin-induced nephrotoxicity via modulating oxidative stress, inflammation and apoptosis

Cisplatin is one of the most significant anticancer. However, its use is associated with numerous toxicities especially nephrotoxicity. The main aim of this work was to examine the protective effect of Gallic acid (GA) and/or cerium oxide nanoparticles (CONPs) synthesized by gamma-irradiation on cisplatin-induced nephrotoxicity in rats. To do that, 48 adult male albino rats were separated into eight groups and received GA (100 mg/kg orally) and/or CONPs (15 mg/kg i. p.) for 10 days before injection with a single dose of cisplatin (7.5 mg/kg i. p.). The findings showed that cisplatin treatment impaired kidney functioning as shown by elevated serum levels of urea and creatinine. Additionally, the oxidative stress indicators (MDA and NO), levels of NF-kB, pro-inflammatory cytokines (IL1-and TNF-) and pro-apoptotic proteins (BAX and caspase-3) were raised after cisplatin injection, while levels of intrinsic anti-oxidants (CAT, SOD, and GSH) and anti-apoptotic protein (Bcl-2) were reduced. Moreover, renal toxicity was confirmed by alteration in normal histological architecture of the kidneys. On the other hand, pretreatment with CONPs and/or GA ameliorated cisplatin-induced nephrotoxicity as evidenced by improvement of renal function parameters and levels of oxidative stress, inflammatory and apoptotic markers in renal tissue along with the renal histopathological changes. This study clarifies how GA and CONPs protect against cisplatin-induced nephrotoxicity and demonstrates any potential synergism between them. Therefore, they can be considered as promising nephroprotective agents during chemotherapy.

Involvement of TRPM2 Channel on Hypoxia-Induced Oxidative Injury, Inflammation, and Cell Death in Retinal Pigment Epithelial Cells: Modulator Action of Selenium Nanoparticles

Hypoxia (HYPX) in several eye diseases such as glaucoma and diabetic retinopathy causes oxidative cell death and inflammation. TRPM2 cation channel is activated by HYPX-induced ADP-ribose (ADPR) and oxidative stress. The protective role of selenium via inhibition of TRPM2 on the HYPX-induced oxidative cytotoxicity and inflammation values in the human kidney cell line was recently reported. However, the protective role of selenium nanoparticles (SeNP) on the values in the retinal pigment epithelial (ARPE-19) cells has not been clarified yet. In the current study, we investigated two subjects. First, we investigated the involvement of TRPM2 channel on the HYPX-induced oxidative injury, inflammation, and apoptosis in the ARPE-19 cells. Second, we investigated the protective role of SeNP via inhibition of TRPM2 channel on the HYPX-induced oxidative injury and apoptosis in the ARPE-19 cells. For the aims, the ARPE-19 cells were divided into four main groups as follows: Control (Ctr), SeNP (2.5 μg/ml for 24 h), HYPX (200 μM CoCl₂ for 24 h), and HYPX+SeNP. The TRPM2 current density and Ca²⁺ fluorescence intensity with an increase of mitochondrial membrane depolarization and oxygen free radical (OFR) generations were increased in the ARPE-19 cells by the treatment of HYPX. There was no increase of Ca²⁺ fluorescence intensity in the pre-treated cells with PARP-1 inhibitors (DPQ and PJ34) or in the presence of Ca²⁺-free extracellular buffer. When HYPX-induced TRPM2 activity was treated by SeNP and TRPM2 (2-APB and ACA) blockers, the increases of OFR generation, cytokine (TNF-α and IL-1β) levels, TRPM2, and PARP-1 expressions were restored. In conclusion, the exposure of HYPX caused mitochondrial oxidative cell cytotoxicity and cell death via TRPM2-mediated Ca²⁺ signaling and may provide an avenue for treating HYPX-induced retinal diseases associated with the excessive OFR and Ca²⁺ influx.

Cerium oxide nanoparticles display antilipogenic effect in rats with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, ranging from steatosis to non-alcoholic steatohepatitis (NASH). Recently, cerium oxide nanoparticles (CeO₂NPs) have emerged as a new antioxidant agent with hepatoprotective properties in experimental liver disease. The aim of the current investigation was to elucidate whether CeO₂NPs display beneficial effects in an experimental model of NAFLD.Therefore, fifteen Wistar rats were subjected to a methionine and choline deficient diet (MCDD) for 6 weeks and intravenously treated with CeO₂NP or vehicle during the weeks three and four of the diet. The effect of CeO₂NPs on serum biochemistry, hepatic steatosis, inflammation, fatty acid content and expression of reactive oxygen species (ROS) and lipid metabolism related genes was assessed. MCDD fed rats showed increased inflammation, enhanced hepatic lipid accumulation of both saturated and unsaturated fatty acids (FAs) and overexpression of genes related to fatty liver and ROS metabolism. Treatment with CeO₂NPs was able to reduce the size and content of hepatocyte lipid droplets, the hepatic concentration of triglyceride- and cholesterol ester-derived FAs and the expression of several genes involved in cytokine, adipokine and chemokine signaling pathways. These findings suggest that CeO₂NPs could be of beneficial value in NAFLD.

Protective Effect of Nanoceria on Cisplatin-Induced Nephrotoxicity by Amelioration of Oxidative Stress and Pro-inflammatory Mechanisms

Cisplatin (CP) is one of the most important anticancer compounds with its therapeutic usefulness in diverse types of solid cancer. However, its use is limited due to nephrotoxicity induced by it. Oxidative stress is an effective participant which contributes actively to pathogenesis of CP-induced nephrotoxicity. Nanoparticle form of a rare earth metal cerium, also known as nanoceria (NC), has come up as a potential antioxidant and anti-inflammatory agent. In the present study, administration of CP in Swiss mice resulted in reduction of body weight, increased oxidative stress and pro-inflammatory cytokine levels including IL-6 and TNF-α along with alteration in normal histological architecture of kidney. On the contrary, NC (0.2 and 2 mg/kg i.p.) ameliorated nephrotoxicity of CP which was evident by reduction in levels of renal injury markers in plasma, i.e., creatinine and blood urea nitrogen. NC ameliorated oxidative stress by showing a reduction in levels of malondialdehyde and increased levels of endogenous antioxidants reduced glutathione and catalase. Further, NC treatment also reduced the levels of pro-inflammatory cytokines. Furthermore, protective effect of NC was also corroborated by histopathological studies wherein, kidneys from CP group showed altered tissue structure after acute as well as chronic exposure of CP while the tissues from treated groups showed absence of alterations in kidney histology. The results from present study suggested that oxidative stress and pro-inflammatory cytokines play a central role in pathogenesis of CP-induced nephrotoxicity and NC provides protection from CP-induced nephrotoxicity due to its antioxidant and anti-inflammatory properties.

Not Only Redox: The Multifaceted Activity of Cerium Oxide Nanoparticles in Cancer Prevention and Therapy

Much information is accumulating on the effect of cerium oxide nanoparticles (CNPs) as cell-protective agents, reducing oxidative stress through their unique ability of scavenging noxious reactive oxygen species via an energy-free, auto-regenerative redox cycle, where superoxides and peroxides are sequentially reduced exploiting the double valence (Ce³⁺/Ce⁴⁺) on nanoparticle surface. In vitro and in vivo studies consistently report that CNPs are responsible for attenuating and preventing almost any oxidative damage and pathology. Particularly, CNPs were found to exert strong anticancer activities, helping correcting the aberrant homeostasis of cancer microenvironment, normalizing stroma-epithelial communication, contrasting angiogenesis, and strengthening the immune response, leading to reduction of tumor mass in vivo. Since these homeostatic alterations are of an oxidative nature, their relief is generally attributed to CNPs redox activity. Other studies however reported that CNPs exert selective cytotoxic activity against cancer cells and sensitize cancer cells to chemotherapy- and radiotherapy-induced apoptosis: such effects are hardly the result of antioxidant activity, suggesting that CNPs exert such important anticancer effects through additional, non-redox mechanisms. Indeed, using Sm-doped CNPs devoid of redox activity, we could recently demonstrate that the radio-sensitizing effect of CNPs on human keratinocytes is independent from the redox switch. Mechanisms involving particle dissolution with release of toxic Ce⁴⁺ atoms, or differential inhibition of the catalase vs. SOD-mimetic activity with accumulation of H₂O₂ have been proposed, explaining such intriguing findings only partially. Much effort is urgently required to address the unconventional mechanisms of the non-redox bioactivity of CNPs, which may provide unexpected medicinal tools against cancer.

Nanoceria ameliorates doxorubicin induced cardiotoxicity: Possible mitigation via reduction of oxidative stress and inflammation

Doxorubicin (DOX) is one of the most commonly used anticancer drugs but its use has been limited due to constraints of cardiotoxic side effects. The precise mechanism underlying cardiotoxicity is not yet fully understood but oxidative stress has been found to be a primary mechanism behind this. In addition, DOX induced cardiotoxicity also shows involvement of proinflammatory cytokines such as IL-6 and TNF-α. Since oxidative stress plays major role in DOX induced cardiotoxicity, different antioxidants have been tried to prevent cardiotoxicity of DOX. Nanoparticles have risen up as a promising material with a wide variety of actions, and cerium oxide nanoparticles or nanoceria (NC) is one of such kind with great antioxidant potential. NC has emerged as a promising antioxidant in different pathological conditions. The present study was aimed to investigate possible protective effects of NC in DOX induced cardiotoxicity. Cardiotoxicity was induced in Swiss mice by DOX administration through i.p. route at a dose level of 15 mg/kg in two divided doses on alternate days. In our study, NC was found to mitigate cardiotoxic potential of DOX and prevented weight loss. NC restored the levels of cardiac injury markers lactate dehydrogenase (LDH) and creatinine kinase MB (CK-MB). Moreover, NC reduced malondialdehyde (MDA) levels and increased endogenous antioxidants such as reduced glutathione (GSH) and catalase levels. In addition, NC decreased proinflammatory cytokine levels and also prevented the alteration in normal structure of heart samples. Our study showed protective effects of NC in DOX induced cardiotoxicity which can become a potential therapeutic intervention against DOX induced cardiotoxicity.

Role of cerium oxide nanoparticle-induced autophagy as a safeguard to exogenous H2O2-mediated DNA damage in tobacco BY-2 cells

The effect of cerium oxide nanoparticle (CeNP) in plants has elicited substantial controversy. While some investigators have reported that CeNP possesses antioxidant properties, others observed CeNP to induce reactive oxygen species (ROS). In spite of considerable research carried out on the effects of CeNP in metazoans, fundamental studies that can unveil its intracellular consequences linking ROS production, autophagy and DNA damage are lacking in plants. To elucidate the impact of CeNP within plant cells, tobacco BY-2 cells were treated with 10, 50 and 250 µg ml-1 CeNP (Ce10, Ce50 and Ce250), for 24 h. Results demonstrated concentration-dependent accumulation of Ca2+ and ROS at all CeNP treatment sets. However, significant DNA damage and alteration in antioxidant defence systems were noted prominently at Ce50 and Ce250. Moreover, Ce50 and Ce250 induced DNA damage, analysed by comet assay and DNA diffusion experiments, complied with the concomitant increase in ROS. Furthermore, to evaluate the antioxidant property of CeNP, treated cells were washed after 24 h (to minimise CeNP interference) and challenged with H2O2 for 3 h. Ce10 did not induce genotoxicity and H2O2 exposure to Ce10-treated cells showed lesser DNA breakage than cells treated with H2O2 only. Interestingly, Ce10 provided better protection over N-acetyl-L-cysteine against exogenous H2O2 in BY-2 cells. CeNP exposure to transgenic BY-2 cells expressing GFP-Atg8 fusion protein exhibited formation of autophagosomes at Ce10. Application of vacuolar protease inhibitor E-64c and fluorescent basic dye acridine orange, further demonstrated accumulation of particulate matters in the vacuole and occurrence of acidic compartments, the autophagolysosomes, respectively. BY-2 cells co-treated with CeNP and autophagy inhibitor 3-methyladenine exhibited increased DNA damage in Ce10 and cell death at all assessed treatment sets. Thus, current results substantiate an alternative autophagy-mediated, antioxidant and geno-protective role of CeNP, which will aid in deciphering novel phenomena of plant-nanoparticle interaction at cellular level.

Slow release of etoposide from dextran conjugation shifts etoposide activity from cytotoxicity to differentiation: A promising tool for dosage control in anticancer metronomic therapy

Drug conjugation, improving drug stability, solubility and body permanence, allows achieving impressive results in tumor control. Here, we show that conjugation may provide a straightforward method to administer drugs by the emerging anticancer metronomic approach, presently consisting of low, repeated doses of cytotoxic drugs used in traditional chemotherapy, thus reducing toxicity without reducing efficiency; however, low dose maintenance in tumor sites is difficult. We show that conjugating the antitumor drug etoposide to dextran via pH-sensitive bond produces slow releasing, apoptosis-proficient conjugates rapidly internalized into acidic lysosomes; importantly, release of active etoposide requires cell internalization and acidic pH. Conjugation, without impairing etoposide-induced complete elimination of tumor cells, shifted the mode of apoptosis from cytotoxicity- to differentiation-related; interestingly, high conjugate doses acted as low doses of free etoposide, thus mimicking the effect of metronomic therapy. This indicates slow release as a promising novel strategy for stabilizing low drug levels in metronomic regimens.

Anti-inflammatory and antioxidant effect of cerium dioxide nanoparticles immobilized on the surface of silica nanoparticles in rat experimental pneumonia

A massage with the potent counter-inflammatory material, cerium dioxide nanoparticles, is promising and the antioxidant properties of CeO₂ are considered the main, if not the only, mechanism of this action. Nevertheless, the elimination of ceria nano-particles from the organism is very slow and there is a strong concern for toxic effect of ceria due to its accumulation. To overcome this problem, we engineered a combined material in which cerium nanoparticles were immobilized on the surface of silica nanoparticles (CeO₂ NP), which is shown to be easily removed from an organism and could be used as carriers for nano-ceria. In our study particle size was 220±5nm, Zeta-potential -4.5mV (in water), surface charge density -17.22μC/cm² (at pH 7). Thirty-six male Wistar rats, 5 months old and 250-290g were divided into four groups: 1) control; 2) CeO₂ NP treatment; 3) experimental pneumonia (i/p LPS injection, 1mg/kg); and 4) experimental pneumonia treated with CeO₂ NP (4 times during the study in dosage of 0.6mg/kg with an orogastric catheter). Gas exchange and pulmonary ventilation were measured four times: 0, 1, 3 and 24h after LPS injection in both untreated and CeO₂ NP-treated animals. The mRNA of TNF-α, Il-6, and CxCL2 were determined by RT-PCR. ROS-generation in blood plasma and lung tissue homogenates were measured by means of lucigenin- and luminol-enhanced chemiluminescence. Endotoxemia in the acute phase was associated with: (1) pathological changes in lung morphology; (2) increase of ROS generation; (3) enhanced expression of CxCL2; and (4) a gradual decrease of VO₂ and V_E. CeO2 NP treatment of intact animals did not make any changes in all studied parameters except for a significant augmentation of VO₂ and V_E. CeO₂ NP treatment of rats with pneumonia created positive changes in diminishing lung tissue injury, decreasing ROS generation in blood and lung tissue and decreasing pro-inflammatory cytokine expression (TNF-α, Il-6 and CxCL2). Oxygen consumption in this group was increased compared to the LPS pneumonia group. In our study we have shown anti-inflammatory and antioxidant effects of CeO₂ NP. In addition, this paper is the first to report that CeO₂ NP stimulates oxygen consumption in both healthy rats, and rats with pneumonia. We propose the key in understanding the mechanisms behind the phenomena lies in the property of CeO₂ NP to scavenge ROS and the influence of this potent antioxidant on mitochondrial function. The study of biodistribution and elimination of СеО₂NP is the purpose of our ongoing study.

Cerium dioxide nanoparticles did not alter the functional and morphologic characteristics of ram sperm during short-term exposure

The aim of the study was to investigate the interaction and the short-term effects of increasing doses of cerium dioxide nanoparticles (CeO2 NPs) on ram spermatozoa, stored at 4 °C for up to 24 hours, on the main functional and kinematic parameters. Spermatozoa were incubated with 0, 22, 44, and 220 μg/mL of CeO2 NPs at 4 °C and submitted at 0, 2, and 24 hours to the following analyses: (1) intracellular uptake of CeO2 NPs by the spermatozoa; (2) kinematic parameters; (3) acrosome and membrane integrity; (4) integrity of DNA; (5) mitochondrial activity; (6) ROS production. The results indicated that the exposure of spermatozoa to increasing doses of nanoceria was well tolerated. No intracellular uptake of NPs by the cells was observed and both kinematic parameters and status of the membranes were not affected by the incubation with NPs (P > 0.05). Moreover, no influence on the redox status of spermatozoa and on the levels of fragmentation of DNA was reported among groups at any time (P > 0.05). The data collected provide new information about the impact of CeO2 NPs on the male gamete in large animal model and could open future perspectives about their biomedical use in the assisted reproductive techniques.

Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic effects on cells. Therefore, improvements in cosmetic solar shield technology are a strong priority. CeO2 nanoparticles are not only UV refractors but also potent biological antioxidants due to the surface 3+/4+ valency switch, which confers anti-inflammatory, anti-ageing and therapeutic properties. Herein, UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of CeO2vs. TiO2 nanoparticles on reporter cells. TiO2 irradiated with UV (especially UVA) exerted strong photocatalytic effects, superimposing their pro-oxidant, cell-damaging and mutagenic action when induced by UV, thereby worsening the UV toxicity. On the contrary, irradiated CeO2 nanoparticles, via their Ce(3+)/Ce(4+) redox couple, exerted impressive protection on UV-treated cells, by buffering oxidation, preserving viability and proliferation, reducing DNA damage and accelerating repair; strikingly, they almost eliminated mutagenesis, thus acting as an important tool to prevent skin cancer. Interestingly, CeO2 nanoparticles also protect cells from the damage induced by irradiated TiO2, suggesting that these two particles may also complement their effects in solar lotions. CeO2 nanoparticles, which intrinsically couple UV shielding with biological and genetic protection, appear to be ideal candidates for next-generation sun shields.

Catalytic Properties and Biomedical Applications of Cerium Oxide Nanoparticles

Cerium oxide nanoparticles (Nanoceria) have shown promise as catalytic antioxidants in the test tube, cell culture models and animal models of disease. However given the reactivity that is well established at the surface of these nanoparticles, the biological utilization of Nanoceria as a therapeutic still poses many challenges. Moreover the form that these particles take in a biological environment, such as the changes that can occur due to a protein corona, are not well established. This review aims to summarize the existing literature on biological use of Nanoceria, and to raise questions about what further study is needed to apply this interesting catalytic material to biomedical applications. These questions include: 1) How does preparation, exposure dose, route and experimental model influence the reported effects of Nanoceria in animal studies? 2) What are the considerations to develop Nanoceria as a therapeutic agent in regards to these parameters? 3) What biological targets of reactive oxygen species (ROS) and reactive nitrogen species (RNS) are relevant to this targeting, and how do these properties also influence the safety of these nanomaterials?