Nandini D.P.K. Manne

Intratracheal instillation of cerium oxide nanoparticles induces hepatic toxicity in male Sprague-Dawley rats

Background Cerium oxide (CeO2) nanoparticles have been posited to have both beneficial and toxic effects on biological systems. Herein, we examine if a single intratracheal instillation of CeO2 nanoparticles is associated with systemic toxicity in male Sprague-Dawley rats. Methods and results Compared with control animals, CeO2 nanoparticle exposure was associated with increased liver ceria levels, elevations in serum alanine transaminase levels, reduced albumin levels, a diminished sodium-potassium ratio, and decreased serum triglyceride levels (P < 0.05). Consistent with these data, rats exposed to CeO2 nanoparticles also exhibited reductions in liver weight (P < 0.05) and dose-dependent hydropic degeneration, hepatocyte enlargement, sinusoidal dilatation, and accumulation of granular material. No histopathological alterations were observed in the kidney, spleen, and heart. Analysis of serum biomarkers suggested an elevation of acute phase reactants and markers of hepatocyte injury in the rats exposed to CeO2 nanoparticles. Conclusion Taken together, these data suggest that intratracheal instillation of CeO2 nanoparticles can result in liver damage.

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

Cerium oxide (CeO2) nanoparticles have been posited to exhibit potent anti-oxidant activity which may allow for the use of these materials in biomedical applications. Herein, we investigate whether CeO2 nanoparticle administration can diminish right ventricular (RV) hypertrophy following four weeks of monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH). Male Sprague Dawley rats were randomly divided into three groups: control, MCT only (60 mg/kg), or MCT + CeO2 nanoparticle treatment (60 mg/kg; 0.1 mg/kg). Compared to the control group, the RV weight to body weight ratio was 45% and 22% higher in the MCT and MCT + CeO2 groups, respectively (p < 0.05). Doppler echocardiography demonstrated that CeO2 nanoparticle treatment attenuated monocrotaline-induced changes in pulmonary flow and RV wall thickness. Paralleling these changes in cardiac function, CeO2 nanoparticle treatment also diminished MCT-induced increases in right ventricular (RV) cardiomyocyte cross sectional area, β-myosin heavy chain, fibronectin expression, protein nitrosylation, protein carbonylation and cardiac superoxide levels. These changes with treatment were accompanied by a decrease in the ratio of Bax/Bcl2, diminished caspase-3 activation and reduction in serum inflammatory markers. Taken together, these data suggest that CeO2 nanoparticle administration may attenuate the hypertrophic response of the heart following PAH.

Inhibition of MAP kinase/NF-kB mediated signaling and attenuation of lipopolysaccharide induced severe sepsis by cerium oxide nanoparticles.

Sepsis is a life threatening disease that is associated with high mortality. Existing treatments have failed to improve survivability in septic patients. The purpose of this present study is to evaluate whether cerium oxide nanoparticles (CeO2NPs) can prevent lipopolysaccharide (LPS) induced severe sepsis mortality by preventing hepatic dysfunction in male Sprague Dawley rats. Administration of a single dose (0.5 mg/kg) of CeO2NPs intravenously to septic rats significantly improved survival rates and functioned to restore body temperature, respiratory rate and blood pressure towards baseline. Treatment-induced increases in animal survivability were associated with decreased hepatic damage along with reductions in serum cytokines/chemokines, and diminished inflammatory related signaling. Kupffer cells and macrophage cells exposed to CeO2NPs exhibited decreases in LPS-induced cytokine release (TNF-α, IL-1β, IL-6, HMGB1) which were associated with diminished cellular ROS, reduced levels of nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and decreased nuclear factor-kappa light chain enhancer of activated B cells (NF-kB) transcriptional activity. The findings of this study indicate that CeO2NPs may be useful as a therapeutic agent for sepsis.

Altered cardiac muscle mTOR regulation during the progression of cancer cachexia in the ApcMin/+ mouse

Cancer cachexia is a muscle wasting condition that occurs in response to a malignant growth in the body. The mechanisms regulating cardiac muscle mass with cachexia are not well understood. Using the ApcMin/+ mouse model of colorectal cancer, we investigated how cachexia affects the regulation of 5′-adenosine monophosphate-activated protein kinase (AMPK), protein kinase B (Akt) and mammalian target of rapamycin (mTOR) signaling in the heart. Compared to age-matched C57BL/6 (BL6) mice, ApcMin/+ body mass and heart mass were lower at 12 (11±5 and 8±3%, respectively) and 20 weeks (26±3 and 6±4%, respectively) of age (P<0.05). Diminished heart mass in the 20-week-old ApcMin/+ mice coincided with a decreased rate of myofibrillar protein synthesis and increased AMPKα phosphorylation. Cachexia decreased mTOR phosphorylation and the phosphorylation of the mTOR substrates, S6 ribosomal protein and 4EBP1 independent of Akt activation. These changes in mTOR-related protein signaling were accompanied by modest increases in the amount of Beclin1 but not protein ubiquitination or cardiomyocyte apoptosis. Taken together, these data suggest that loss of cardiac mass during cachexia progression in the ApcMin/+ mouse is associated with an Akt-independent suppression of anabolic signaling and evidence of increased autophagy.

Metabolic syndrome-induced tubulointerstitial injury: Role of oxidative stress and preventive effects of acetaminophen

The prevalence of metabolic syndrome persistently increases and affects over 30% of U.S. adults. To study how metabolic syndrome may induce tubulointerstitial injury and whether acetaminophen has renal-protective properties, 4-week-old obese Zucker rats were randomly assigned into three groups, control (OC), vehicle dimethyl sulfoxide (OV), and acetaminophen treatment (30 mg/kg/day for 26 weeks), and lean Zucker rats served as healthy controls. Significant tubulointerstitial injuries were observed in both OC and OV animals, evidenced by increased tubular cell death, tubular atrophy/dilation, inflammatory cell infiltration, and fibrosis. These tubulointerstitial alterations were significantly reduced by treatment with a chronic but low dose of acetaminophen, which acted to diminish NADPH oxidase isoforms Nox2 and Nox4 and decrease tubulointerstitial oxidative stress (reduced tissue superoxide and macromolecular oxidation). Decreased oxidative stress by acetaminophen was paralleled by the reduction of tubular proapoptotic signaling (diminished Bax/Bcl-2 ratio and caspase 3 activation) and the alleviation of tubular epithelial-to-mesenchymal transition (decreased transforming growth factor β, connective tissue growth factor, α-smooth muscle actin, and laminin). These data suggest that increased oxidative stress plays a critical role in mediating metabolic syndrome-induced tubulointerstitial injury and provide the first evidence suggesting that acetaminophen may be of therapeutic benefit for the prevention of tubulointerstitial injury.

Overload induced heat shock proteins (HSPs), MAPK and miRNA (miR-1 and miR133a) response in insulin-resistant skeletal muscle.

Background: Insulin resistance (IR) may decrease muscle adaptability. Heat shock proteins (HSPs), mitogen-activated protein kinases (MAPKs), and miRNA are thought to play a role in muscle hypertrophy but it is unclear if IR may affect their regulation. Methods: Soleus muscles of lean Zucker (LZ) and insulin resistant obese Zucker (OZ) rats were overloaded for 7 or 21 days and subjected to immunoblotting and RT-PCR. Results: IR was associated with decreased muscle hypertrophy. Overload increased HSP27 phosphorylation in both the LZ and OZ rats at day 7 but only in the LZ at day 21. IR was associated with diminished overload induced MAPK phosphorylation and decreased expression of miR-1 and miR133. Overload decreased mir-1 levels in both the LZ and OZ but to a greater extent in the LZ animals. Conclusion: These results suggest that alterations in the regulation of HSPs, MAPKs and miRNA may be associated with the diminished hypertrophy of IR muscle.

Effect of cerium oxide nanoparticles on sepsis induced mortality and NF-κB signaling in cultured macrophages.

AIM To investigate whether cerium oxide (CeO2) nanoparticles could be used for the treatment of severe sepsis. MATERIALS & METHODS Cecal peritonitis was induced in male Sprague-Dawley rats in the presence and absence of CeO2 nanoparticles. Cultured macrophages (RAW264.7 cells) were challenged with lipopolysaccharide in the absence and presence of CeO2 nanoparticles. The effect of nanoparticles on the growth of Escherichia coli and Staphylococcus aureus was determined in culture. RESULTS Nanoparticle treatment decreased sepsis-induced mortality, organ damage, serum IL-6, blood urea nitrogen and inflammatory markers. Nanoparticle treatment diminished lipopolysaccharide-induced cytokine release and p65-nuclear factor-KB (NF-KB) activation in cultured RAW264.7 cells. Exposure to CeO2 nanoparticles inhibited E. coli growth. CONCLUSION The findings of this study indicate that CeO2 nanoparticles may be useful for the treatment of sepsis.

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 &mgr;L 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 inhibit lipopolysaccharide induced MAP kinase/NF-kB mediated severe sepsis.

The life threatening disease of sepsis is associated with high mortality. Septic patient survivability with currently available treatments has failed to improve. The purpose of this study was to evaluate whether lipopolysaccharide (LPS) induced sepsis mortality and associated hepatic dysfunction can be prevented by cerium oxide nanoparticles (CeO2NPs) treatment in male Sprague Dawley rats. Here we provide the information about the methods processing of raw data related to our study published in Biomaterials (Selvaraj et al., Biomaterials, 2015, In press) and Data in Brief (Selvaraj et al., Data in Brief, 2015, In Press). The data present here provides confirmation of cerium oxide nanoparticle treatments ability to prevent the LPS induced sepsis associated changes in physiological, blood cell count, inflammatory protein and growth factors in vivo. In vitro assays investigation the treated of macrophages cells with different concentrations of cerium oxide nanoparticle demonstrate that concentration of cerium oxide nanoparticles below 1 µg/ml did not significantly influence cell survival as determined by the MTT assay.

Exposure to Cerium Oxide Nanoparticles Is Associated With Activation of Mitogen-activated Protein Kinases Signaling and Apoptosis in Rat Lungs

Objectives: With recent advances in nanoparticle manufacturing and applications, potential exposure to nanoparticles in various settings is becoming increasing likely. No investigation has yet been performed to assess whether respiratory tract exposure to cerium oxide (CeO2) nanoparticles is associated with alterations in protein signaling, inflammation, and apoptosis in rat lungs. Methods: Specific-pathogen-free male Sprague-Dawley rats were instilled with either vehicle (saline) or CeO2 nanoparticles at a dosage of 7.0 mg/kg and euthanized 1, 3, 14, 28, 56, or 90 days after exposure. Lung tissues were collected and evaluated for the expression of proteins associated with inflammation and cellular apoptosis. Results: No change in lung weight was detected over the course of the study; however, cerium accumulation in the lungs, gross histological changes, an increased Bax to Bcl-2 ratio, elevated cleaved caspase-3 protein levels, increased phosphorylation of p38 MAPK, and diminished phosphorylation of ERK-1/2-MAPK were detected after CeO2 instillation (p<0.05). Conclusions: Taken together, these data suggest that high-dose respiratory exposure to CeO2 nanoparticles is associated with lung inflammation, the activation of signaling protein kinases, and cellular apoptosis, which may be indicative of a long-term localized inflammatory response.