Expression Of Endogenous Antioxidants Research Articles

Repetitive Administration of Low-Dose Lipopolysaccharide Improves Repeated Social Defeat Stress-Induced Behavioral Abnormalities and Aberrant Immune Response.

Repetitive exposure of innate immune cells to a subthreshold dosage of endotoxin components may modulate inflammatory responses. However, the regulatory mechanisms in the interactions between the central nervous system (CNS) and the immune system remain unclear. This study aimed to investigate the effects of lipopolysaccharide (LPS) preconditioning in repeated social defeat stress (RSDS)-induced abnormal immune responses and behavioral impairments. This study aimed to elucidate the mechanisms that underlie the protective effects of repeated administration of a subthreshold dose LPS on behavioral impairments using the RSDS paradigm. LPS preconditioning improved abnormal behaviors in RSDS-defeated mice, accompanied by decreased monoamine oxidases and increased glucocorticoid receptor expression in the hippocampus. In addition, pre-treated with LPS significantly decreased the recruited peripheral myeloid cells (CD11b+CD45hi), mainly circulating inflammatory monocytes (CD11b+CD45hiLy6ChiCCR2+) into the brain in response to RSDS challenge. Importantly, we found that LPS preconditioning exerts its protective properties by regulating lipocalin-2 (LCN2) expression in microglia, which subsequently induces expressions of chemokine CCL2 and pro-inflammatory cytokine. Subsequently, LPS-preconditioning lessened the resident microglia population (CD11b+CD45intCCL2+) in the brains of the RSDS-defeated mice. Moreover, RSDS-associated expressions of leukocytes (CD11b+CD45+CCR2+) and neutrophils (CD11b+CD45+Ly6G+) in the bone marrow, spleen, and blood were also attenuated by LPS-preconditioning. In particular, LPS preconditioning also promoted the expression of endogenous antioxidants and anti-inflammatory proteins in the hippocampus. Our results demonstrate that LPS preconditioning ameliorates lipocalin 2-associated microglial activation and aberrant immune response and promotes the expression of endogenous antioxidants and anti-inflammatory protein, thereby maintaining the homeostasis of pro-inflammation/anti-inflammation in both the brain and immune system, ultimately protecting the mice from RSDS-induced aberrant immune response and behavioral changes.

Antioxidant Activity of Unripe Sapodilla Fruit Extract (Manilkara zapota L.) through Nrf2 and SOD Expression in Type 1 Diabetic Mice

This research aims to analyze the effect of unripe sapodilla fruit extract on endogenous antioxidant expression in T1DM BALB/c mice and its free radical scavenging activity. Manilkara zapota extract (MzE) is an aqueous extract of unripe sapodilla fruit and was obtained by maceration and freeze-drying process. This study used 25 male BALB/c mice with 7-weeks-old of age. They were divided randomly into five groups (n=5) before treatment. A single high dose (145 mg/kg BW) of streptozotocin (STZ) was intraperitoneally injected to induce type 1 diabetes mellitus (T1DM). MzE was given orally once each day for 14 days. Liver cells were isolated and immunoassay with anti-superoxide dismutase (SOD) and anti-nuclear factor erythroid 2-related Factor 2 (Nrf2), and then the results were analyzed by flow cytometry. Diphenylpicrylhydrazyl (DPPH) assay was performed to analyze free radical scavenging. Data were analyzed statistically with one-way ANOVA (p<0.05). The result showed that the glucose levels in diabetic mice after MzE administration were significantly lower than in the DM group. MzE treatment increased the expression of Nrf2 and SOD in diabetic mice. MzE could scavenge DPPH with the IC50 value obtained at 48.35 μg/mL, while ascorbic acid as a control could scavenge DPPH with the IC50 value at 22.24 μg/mL. The increase in the scavenging activity is in line with the increase in extract concentration. In conclusion, this study revealed that MzE can be an endogenous antioxidant enhancer by improving the expression of Nrf-2, SOD and can inhibit free radicals as an exogenous antioxidant in T1DM

Ferroptosis Signaling in Pancreatic β-Cells: Novel Insights & Therapeutic Targeting.

Metabolic stress impairs pancreatic β-cell survival and function in diabetes. Although the pathophysiology of metabolic stress is complex, aberrant tissue damage and β-cell death are brought on by an imbalance in redox equilibrium due to insufficient levels of endogenous antioxidant expression in β-cells. The vulnerability of β-cells to oxidative damage caused by iron accumulation has been linked to contributory β-cell ferroptotic-like malfunction under diabetogenic settings. Here, we take into account recent findings on how iron metabolism contributes to the deregulation of the redox response in diabetic conditions as well as the ferroptotic-like malfunction in the pancreatic β-cells, which may offer insights for deciphering the pathomechanisms and formulating plans for the treatment or prevention of metabolic stress brought on by β-cell failure.

Limonene protects human skin keratinocytes against UVB-induced photodamage and photoaging by activating the Nrf2-dependent antioxidant defense system.

Long term exposure to solar ultraviolet B (UVB) radiation is one of the primary factors of premature skin aging and is referred to as photoaging. Also, mammalian skin exposed to UVB triggers an increase in production of α-melanocyte-stimulating hormone (α-MSH), which is critically involved in the pathogenesis of hyperpigmentary skin diseases. This study investigated the protective effect of limonene on UVB-induced photodamage and photoaging in immortalized human skin keratinocytes (HaCaT) in vitro. Initially, we determined cell viability and levels of reactive oxygen species (ROS) in UVB-irradiated HaCaT cells. Pretreatment with limonene increased cell viability followed by inhibition of intracellular ROS generation in UVB-irradiated HaCaT cells. Interestingly, the antioxidative activity of limonene was directly correlated with an increase in expression of endogenous antioxidants, including heme oxygenase 1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO-1), and γ-glutamylcysteine synthetase (γ-GCLC), which was associated with enhanced nuclear translocation and activation of NF-E2-related factor-2 (Nrf2). Indeed, Nrf2 knockdown reduced limonene's protective effects. Additionally, we observed that limonene treatment inhibited UVB-induced α-MSH secretion followed by inhibition of proopiomelanocortin (POMC) via suppression of p53 transcriptional activation. Moreover, limonene prevented UVB-mediated depletion of tight junction regulatory proteins, including occludin and zonula occludens-1. On the other hand, limonene treatment significantly decreased matrix metalloproteinase-2 levels in UVB-irradiated HaCaT cells. Based on these results, limonene may have a dermato-protective effect in skin cells by activating the Nrf2-dependent cellular antioxidant defense system.

New Insight on the Bioactivity of Solanum aethiopicum Linn. Growing in Basilicata Region (Italy): Phytochemical Characterization, Liposomal Incorporation, and Antioxidant Effects

Food extract’s biological effect and its improvement using nanotechnologies is one of the challenges of the last and the future decades; for this reason, the antioxidant effect of scarlet eggplant extract liposomal incorporation was investigated. Scarlet eggplant (Solanum aethiopicum L.) is a member of the Solanaceae family, and it is one of the most consumed vegetables in tropical Africa and south of Italy. This study investigated the antioxidant activity and the phytochemical composition of S. aethiopicum grown in the Basilicata Region for the first time. The whole fruit, peel, and pulp were subjected to ethanolic exhaustive maceration extraction, and all extracts were investigated. The HPLC-DAD analysis revealed the presence of ten phenolic compounds, including hydroxycinnamic acids, flavanones, flavanols, and four carotenoids (one xanthophyll and three carotenes). The peel extract was the most promising, active, and the richest in specialized metabolites; hence, it was tested on HepG2 cell lines and incorporated into liposomes. The nanoincorporation enhanced the peel extract’s antioxidant activity, resulting in a reduction of the concentration used. Furthermore, the extract improved the expression of endogenous antioxidants, such as ABCG2, CAT, and NQO1, presumably through the Nrf2 pathway.

Direct Cardiac Actions of Sodium-Glucose Cotransporter 2 Inhibition Improve Mitochondrial Function and Attenuate Oxidative Stress in Pressure Overload-Induced Heart Failure.

Clinical trials showed that sodium-glucose cotransporter 2 (SGLT2) inhibitors, a class of drugs developed for treating diabetes mellitus, improve prognosis of patients with heart failure (HF). However, the mechanisms for cardioprotection by SGLT2 inhibitors are still unclear. Mitochondrial dysfunction and oxidative stress play important roles in progression of HF. This study tested the hypothesis that empagliflozin (EMPA), a highly selective SGLT2 inhibitor, improves mitochondrial function and reduces reactive oxygen species (ROS) while enhancing cardiac performance through direct effects on the heart in a non-diabetic mouse model of HF induced by transverse aortic constriction (TAC). EMPA or vehicle was administered orally for 4 weeks starting 2 weeks post-TAC. EMPA treatment did not alter blood glucose or body weight but significantly attenuated TAC-induced cardiac dysfunction and ventricular remodeling. Impaired mitochondrial oxidative phosphorylation (OXPHOS) in failing hearts was significantly improved by EMPA. EMPA treatment also enhanced mitochondrial biogenesis and restored normal mitochondria morphology. Although TAC increased mitochondrial ROS and decreased endogenous antioxidants, EMPA markedly inhibited cardiac ROS production and upregulated expression of endogenous antioxidants. In addition, EMPA enhanced autophagy and decreased cardiac apoptosis in TAC-induced HF. Importantly, mitochondrial respiration significantly increased in ex vivo cardiac fibers after direct treatment with EMPA. Our results indicate that EMPA has direct effects on the heart, independently of reductions in blood glucose, to enhance mitochondrial function by upregulating mitochondrial biogenesis, enhancing OXPHOS, reducing ROS production, attenuating apoptosis, and increasing autophagy to improve overall cardiac function in a non-diabetic model of pressure overload-induced HF.

Targeting Endogenous Antioxidant Capacity to Prevent Vascular Dysfunction Induced by Limb Immobilization

BackgroundBrief periods of limb disuse that accompany orthopedic injuries can impair vascular function and increase cardiovascular disease risk. Specifically, limb immobilization elicits a decrease in vascular shear stress which leads to an increase in oxidative stress and impaired vasodilation. We hypothesized that increasing the activation of nuclear factor‐erythroid factor 2‐related factor 2 (Nrf2), a critical transcription factor that regulates expression of endogenous antioxidants, using a novel, naturally occurring, supplement (PB125), would preserve vascular function during 14 days of limb immobilization.MethodsTen young, healthy individuals were randomized to receive either PB125 (100mg, N=6, 3M/3F, 28±5 y, BMI= 25±6 kg/m2) or placebo (N=4, 1M/3F, 23±4 y, BMI=24±3 kg/m2). Utilizing Doppler ultrasound, before and after 14 days of leg immobilization, leg blood flow (LBF) and vascular conductance (LVC) were measured in the common femoral artery at rest and during passive leg movement (PLM), and during knee‐extensor (KE) exercise at 3 relative intensities (40, 60, 80% of max; KE max = 35±10W). Additionally, flow mediated dilation (FMD) and post‐occlusive reactive hyperemia were assessed in the popliteal and brachial arteries.ResultsLower limb immobilization reduced daily step count by 53 ± 19% in both groups (PB125 vs. placebo p > 0.05). Femoral, popliteal, and brachial artery diameters were not significantly different following immobilization. Resting LBF and LVC were lower following immobilization in the placebo group (pre vs. post; LBF: 485±124 vs. 357±106 ml/min, p = 0.001; LVC: 5.2±1.1 vs. 3.7±0.9 ml/min/mmHg, p = 0.001), but were preserved in the PB125 group (LBF: 239±63 vs. 237±78 ml/min, p > 0.05; LVC: 2.6±0.6 vs. 2.6±0.7 ml/min/mmHg, p > 0.05). However, LBF and LVC during KE exercise were not impacted by limb immobilization. Microvascular function, as assessed by the hyperemic response to PLM, was diminished in the placebo group (LVC Δpeak: 6.8±2.8 vs. 3.7±1.4 ml/min/mmHg, p = 0.049), but preserved in the PB125 group (LVC Δpeak: 3.0±0.6 vs. 3.0±1.8 ml/min/mmHg p > 0.05). Conversely, microvascular function, assessed by reactive hyperemia, was unchanged in both the popliteal and brachial arteries. Macrovascular function changes due to immobilization were limb‐specific, with a decrease in popliteal artery FMD with placebo (6.5±4.1 vs. 1.9±1.6 %, p = 0.046) and preservation with PB125 (4.4±3.6 vs. 2.8±1.9 %, p > 0.05), while brachial artery FMD was unchanged in both groups (p > 0.05).ConclusionsLimb immobilization induced both microvascular and macrovascular changes in the leg which may contribute to the attenuated LBF and LVC at rest. Administration of PB125 preserved vascular function during disuse, presumably by mitigating the deleterious impact of oxidative stress. Hence, PB125 supplementation, and, therefore, augmented endogenous antioxidant capacity, appears to mitigate the negative vascular effects of limb disuse.

Effects of selenium treatment on endogenous antioxidant capacity in signal crayfish (Pacifastacus leniusculus)

Selenium is an essential element that plays a role in numerous physiological processes and is critical for the maintenance of a strong endogenous antioxidant system. Previous work by our research group reported that the organophosphate pesticide dimethoate decreased glutathione S-transferase activity (GST) in signal crayfish (Pacifastacus leniusculus) collected from the Boise River (Idaho, USA). The goals of this study were to examine whether: 1) sodium selenite modulated the endogenous antioxidants glutathione (GSH), metallothionein (MT), and glutathione S-transferase (GST), thus suggesting a mechanism of antioxidant activity, 2) dimethoate exposure (pro-oxidant stressor) decreased GST activity in a localized population of signal crayfish collected from the Snake River (Idaho, USA), and 3) investigate whether selenium cotreatment ameliorated the adverse effects of dimethoate on GST activity due to the antioxidant properties associated with selenium. Selenium and dimethoate treatments (and co-treatments) did not modulate GSH or MT concentrations at the doses tested in this study. Furthermore, neither selenium nor dimethoate was factors influencing GST activity, and no interaction was found between the treatments. While our results did not support our predictions, they are suggestive and future studies examining the protective role of selenium in pro-oxidant exposure in this species are warranted. Population-specific responses as well as seasonal variations in endogenous antioxidant expression should be considered in future experiments.

Regulatory Effects of Quercetin on M1/M2 Macrophage Polarization and Oxidative/Antioxidative Balance.

Macrophage polarization plays essential and diverse roles in most diseases, such as atherosclerosis, adipose tissue inflammation, and insulin resistance. Homeostasis dysfunction in M1/M2 macrophage polarization causes pathological conditions and inflammation. Neuroinflammation is characterized by microglial activation and the concomitant production of pro-inflammatory cytokines, leading to numerous neurodegenerative diseases and psychiatric disorders. Decreased neuroinflammation can be obtained by using natural compounds, including flavonoids, which are known to ameliorate inflammatory responses. Among flavonoids, quercetin possesses multiple pharmacological applications and regulates several biological activities. In the present study, we found that quercetin effectively inhibited the expression of lipocalin-2 in both macrophages and microglial cells stimulated by lipopolysaccharides (LPS). The production of nitric oxide (NO) and expression levels of the pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, were also attenuated by quercetin treatment. Our results also showed that quercetin significantly reduced the expression levels of the M1 markers, such as interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1β, in the macrophages and microglia. The M1 polarization-associated chemokines, C–C motif chemokine ligand (CCL)-2 and C-X-C motif chemokine ligand (CXCL)-10, were also effectively reduced by the quercetin treatment. In addition, quercetin markedly reduced the production of various reactive oxygen species (ROS) in the microglia. The microglial phagocytic ability induced by the LPS was also effectively reduced by the quercetin treatment. Importantly, the quercetin increased the expression levels of the M2 marker, IL-10, and the endogenous antioxidants, heme oxygenase (HO)-1, glutamate-cysteine ligase catalytic subunit (GCLC), glutamate-cysteine ligase modifier subunit (GCLM), and NAD(P)H quinone oxidoreductase-1 (NQO1). The enhancement of the M2 markers and endogenous antioxidants by quercetin was activated by the AMP-activated protein kinase (AMPK) and Akt signaling pathways. Together, our study reported that the quercetin inhibited the effects of M1 polarization, including neuroinflammatory responses, ROS production, and phagocytosis. Moreover, the quercetin enhanced the M2 macrophage polarization and endogenous antioxidant expression in both macrophages and microglia. Our findings provide valuable information that quercetin may act as a potential drug for the treatment of diseases related to inflammatory disorders in the central nervous system.

Sodium butyrate ameliorates neurotoxicity and exerts anti-inflammatory effects in high fat diet-fed mice

The prevalence of high-fat diet consumption-related disorders is increasing, and it is often associated with oxidative stress, inflammation, and dysregulation in the brain may lead to neurodegenerative diseases (NDDs). Our study aims to evaluate the neuroprotective effects of sodium butyrate (NaB) on HFD-fed mice. In this study, four-week-old male C57Bl/6NTac mice were divided into three groups; the control group, the HFD group, and the HFD + NaB group where mice received 11 mg/kg body weight of NaB with HFD. Western blotting, reverse transcription-PCR, and ELISA were used for biochemical analysis of brain specimens. We found that NaB restored bodyweight and attenuated P-53, Bcl-2-associated X protein (BAX), and caspase cascades in the brains of HFD-fed mice. In addition. NaB reduced the expressions of proinflammatory cytokines and positively modulated antioxidant biomarkers. NaB treatment upregulated the expression of the growth factor-related factors PPARγ, CREB, and BDNF in the brain tissues of HFD-fed mice. Furthermore, we found that NaB significantly ameliorated glucocorticoid receptor and NLRP3 inflammasome expression. Based on our findings, NaB suppressed apoptotic and inflammatory cytokines and enhanced the expression of endogenous antioxidants in brain tissues of HFD-fed mice. Our data strongly suggests that NaB could be utilized as an effective therapeutic agent for NDDs.

Nociceptin Increases Antioxidant Expression in the Kidney, Liver and Brain of Diabetic Rats.

Simple SummaryNociceptin (NC) is a small peptide implicated in the physiology of pain, learning and memory. Here we investigated the role of NC in the induction of antioxidants in the kidney, liver, and the brain of diabetic rats using morphological and biochemical methods. Normal and diabetic animals were treated with NC for 5 days. Catalase (CAT) was expressed in the kidney, liver, and the neurons of the brain. Although CAT was markedly (p < 0.05) lower in the tubules of the kidney of normal and diabetic animals after NC treatment, NC significantly (p < 0.001) increased the presence of CAT in the liver and brain of diabetic rats. Superoxide dismutase (SOD) was observed in kidney tubules, hepatocytes, and neurons of the brain. Treatment with NC markedly (p < 0.001) increased the level of SOD in hepatocytes and neurons of the brain. Glutathione reductase (GRED) was seen in the convoluted tubules of the kidney, hepatocytes and neurons of the brain. Treatment with NC markedly increased (p < 0.001) the expression of GRED in kidney tubules, hepatocytes and neurons of the brain. In conclusion, NC can help diabetic patients mitigate the effects of oxidative stress by its ability to induce endogenous antioxidants.Nociceptin (NC) consists of 17 amino acids (aa) and takes part in the processing of learning and memory. The role of NC in the induction of endogenous antioxidants in still unclear. We examined the effect of NC on the expression of endogenous antioxidants in kidney, liver, cerebral cortex (CC), and hippocampus after the onset of diabetes mellitus, using enzyme-linked immunosorbent assay and immunohistochemistry. Exogenous NC (aa chain 1–17; 10 µg/kg body weight) was given intraperitoneally to normal and diabetic rats for 5 days. Our results showed that catalase (CAT) is present in the proximal (PCT) and distal (DCT) convoluted tubules of kidney, hepatocytes, and neurons of CC and hippocampus. The expression of CAT was significantly (p < 0.05) reduced in the kidney of normal and diabetic rats after treatment with NC. However, NC markedly (p < 0.001) increased the expression CAT in the liver and neurons of CC of diabetic rats. Superoxide dismutase (SOD) is widely distributed in the PCT and DCT of kidney, hepatocytes, and neurons of CC and hippocampus. NC significantly (p < 0.001) increased the expression of SOD in hepatocytes and neurons of CC and the hippocampus but not in the kidney. Glutathione reductase (GRED) was observed in kidney tubules, hepatocytes and neurons of the brain. NC markedly increased (p < 0.001) the expression of GRED in PCT and DCT cells of the kidney and hepatocytes of liver and neurons of CC. In conclusion, NC is a strong inducer of CAT, SOD, and GRED expression in the kidney, liver and brain of diabetic rats.

NADPH Oxidase (NOX) Targeting in Diabetes: A Special Emphasis on Pancreatic β-Cell Dysfunction.

In type 2 diabetes, metabolic stress has a negative impact on pancreatic β-cell function and survival (T2D). Although the pathogenesis of metabolic stress is complex, an imbalance in redox homeostasis causes abnormal tissue damage and β-cell death due to low endogenous antioxidant expression levels in β-cells. Under diabetogenic conditions, the susceptibility of β-cells to oxidative damage by NADPH oxidase has been related to contributing to β-cell dysfunction. Here, we consider recent insights into how the redox response becomes deregulated under diabetic conditions by NADPH oxidase, as well as the therapeutic benefits of NOX inhibitors, which may provide clues for understanding the pathomechanisms and developing strategies aimed at the treatment or prevention of metabolic stress associated with β-cell failure.

Modulation of endogenous antioxidants by zinc and copper in signal crayfish (Pacifastacus leniusculus)

Metal pollution is a long-standing concern and bioindicators are commonly used in ecotoxicological studies to monitor impacted wildlife populations for evidence of sublethal effects. Significant variation in the response of common biomarkers to metals is reported across taxa, thus necessitating careful characterization in model organisms. In this study, we describe the regulation of glutathione S-transferase (GST), glutathione (GSH), and metallothionein (MT) by zinc chloride (0.6, 0.9, 1.2, 2.4, 4.8, 9.6 μg g−1) and copper chloride (0.6, 0.9, 1.2 μg g−1) in signal crayfish (Pacifastacus leniusculus). Zinc chloride did not alter GST activity relative to controls in the hepatopancreas. Crayfish exposed to copper chloride exhibited decreased GST activity at the lowest dose tested (0.6 μg g−1) with no change observed at the higher doses. GSH did not change in response to either metal when sexes were grouped together. MT concentrations increased in response to zinc (2.4, 4.6, and 9.6 μg g−1 doses) and copper (0.6, 0.9, and 1.2 μg g−1 doses) in gill tissue. In tail tissue, MT increased at the 2.4 and 4.8 μg g−1 zinc chloride doses and all the concentrations of copper tested. Sex-specific differences in endogenous antioxidant expression were also analyzed with no clear patterns emerging. We concluded that these endpoints are sensitive to zinc and copper in signal crayfish, although careful interpretation is needed when applying them in field studies given the variation in responses, non-monotonic dose responses, and differences in biotic and abiotic factors that inevitably exist in different aquatic ecosystems.

Pharmacological Effect of Muntingia calabura Leaves on the Expression of sod1 and sod2 in Drosophila

The lifespan of Drosophila melanogaster can last longer when consuming ethanol extract of Muntingia calabura leaves (EMCL) before starvation. Lifespan extension can be affected by several factors, including the increased expression of endogenous antioxidants. This study aimed to assess the level of endogenous antioxidants sod1 and sod2 in D. melanogaster upon ingestion of ethanol extract of M. calabura leaves (EMCL) before starvation. Fifty D. melanogaster were divided into five groups: healthy control group, starvation control group, and three groups of EMCL-treated: 0.2% group, 1% group, and 5% group. Each group was fed with fly food in the presence or absence of EMCL for seven days, and all groups, except the healthy control group, were subsequently subjected to a starvation procedure for seven hours. RNA extraction was performed on each group before sod1 and sod2 measurements using the reverse-transcriptase quantitative PCR method. Our results revealed that the expression of sod2 was increased in response to starvation. On the contrary, reduced expression of sod1 was observed in the starvation-treated group. Treatment of flies with EMCL at 1% and 5% increased the mRNA level of sod1, but did not affect the mRNA level of sod2. Taken together, our results demonstrated the potential effect of Muntingia calabura leaves in the modulation of Drosophila sod1 and sod2 gene expression in Drosophila. Similar endogenous antioxidants are present in humans and have been associated with aging, implying that prospective pharmacological investigations are feasible to pursue in future studies.

Therapeutic hypothermia reduces inflammation and oxidative stress in the liver after asphyxial cardiac arrest in rats.

Background Few studies have evaluated the effects of hypothermia on cardiac arrest (CA)-induced liver damage. This study aimed to investigate the effects of hypothermic therapy on the liver in a rat model of asphyxial cardiac arrest (ACA).Methods Rats were subjected to 5-minute ACA followed by return of spontaneous circulation (RoSC). Body temperature was controlled at 33°C±0.5°C or 37°C±0.5°C for 4 hours after RoSC in the hypothermia group and normothermia group, respectively. Liver tissues in each group were collected at 6 hours, 12 hours, 1 day, and 2 days after RoSC. To examine hepatic inflammation, mast cells were stained with toluidine blue. Superoxide anion radical production was evaluated using dihydroethidium fluorescence straining and expression of endogenous antioxidants (superoxide dismutase 1 [SOD1] and SOD2) was examined using immunohistochemistry.Results There were significantly more mast cells in the livers of the normothermia group with ACA than in the hypothermia group with ACA. Gradual increase in superoxide anion radical production was found with time in the normothermia group with ACA, but production was significantly suppressed in the hypothermia group with ACA relative to the normothermia group with ACA. SOD1 and SOD2 levels were higher in the hypothermia group with ACA than in the normothermia group with ACA.Conclusions Experimental hypothermic treatment after ACA significantly inhibited inflammation and superoxide anion radical production in the rat liver, indicating that this treatment enhanced or maintained expression of antioxidants. Our findings suggest that hypothermic therapy after CA can reduce mast cell-mediated inflammation through regulation of oxidative stress and the expression of antioxidants in the liver.

Abstract 13320: Direct Cardiac Actions of Empagliflozin Improve Mitochondrial Oxidative Phosphorylation and Attenuate Pressure-overload Heart Failure

Introduction: The underlying mechanisms by which empagliflozin (EMPA) and other sodium glucose co-transporter 2 (SGLT2) inhibitors attenuate heart failure (HF) are still poorly understood. However, this protection does not appear to be fully explained by their antihyperglycemic or diuretic effects. Hypothesis: EMPA attenuates HF by direct effects on the heart to improve its metabolism and function. Methods: C57BL/6J mice (4-6 months) were subjected to transverse aortic constriction (TAC) or sham surgeries. Two weeks after TAC, EMPA (10 mg/kg/day) or vehicle was administered daily for 4 additional weeks. Cardiac function was assessed by echocardiography and cardiac substrate metabolism measured in isolated perfused hearts. Transmission electron microscopy was used to evaluate mitochondrial morphology and molecular docking analysis to predict potential cardiac targets of EMPA. Results: EMPA increased survival and attenuated adverse left ventricle remodeling and cardiac fibrosis after TAC. EMPA also attenuated left ventricular systolic dysfunction (ejection fraction 51.6 vs. 40.2% p&lt;0.05; fraction shortening 28.8 vs 18.4% p&lt;0.05). EMPA rescued impaired glucose and fatty acid oxidation in failing hearts, while reducing glycolysis. Molecular docking analysis and isolated perfused heart experiments indicated that EMPA can directly bind glucose transporters in the heart to reduce glycolysis, and enhance AMP-activated protein kinase. EMPA treatment enhanced mitochondrial biogenesis, restored mitochondria cristae integrity, increased expression of endogenous antioxidants, and reduced cellular apoptosis caused by leakage of cytochrome C from mitochondria into the cytosol. These beneficial cardiac effects of EMPA occurred despite no alterations in fasting blood glucose, body weight, or daily urine volume. Conclusions. Our study demonstrated that EMPA may directly bind glucose transporters and reduce excessive glycolysis in failing hearts. EMPA enhanced mitochondrial biogenesis, improved mitochondrial oxidative phosphorylation, and reduced mitochondria-mediated apoptosis, thereby attenuating cardiac dysfunction and progression of HF.

Oxidative stress in pancreatic alpha and beta cells as a selection criterion for biocompatible biomaterials

The clinical success rate of islet transplantation, namely independence from insulin injections, is limited by factors that lead to graft failure, including inflammation, acute ischemia, acute phase response, and insufficient vascularization. The ischemia and insufficient vascularization both lead to high levels of oxidative stress, which are further aggravated by islet encapsulation, inflammation, and undesirable cell-biomaterial interactions. To identify biomaterials that would not further increase damaging oxidative stress levels and that are also suitable for manufacturing a beta cell encapsulation device, we studied five clinically approved polymers for their effect on oxidative stress and islet (alpha and beta cell) function. We found that 300 poly(ethylene oxide terephthalate) 55/poly(butylene terephthalate) 45 (PEOT/PBT300) was more resistant to breakage and more elastic than other biomaterials, which is important for its immunoprotective function. In addition, it did not induce oxidative stress or reduce viability in the MIN6 beta cell line, and even promoted protective endogenous antioxidant expression over 7 days. Importantly, PEOT/PBT300 is one of the biomaterials we studied that did not interfere with insulin secretion in human islets.

Associations Among Physical Activity Level and Skeletal Muscle Antioxidants in Older Adults.

Endogenous antioxidants are critical to limiting cellular oxidative damage. The authors determined if habitual physical activity (PA) and cardiorespiratory fitness were associated with skeletal muscle expression of endogenous antioxidants (superoxide dismutase, catalase, and glutathione peroxidase) and circulating oxidative stress markers (serum 8-hydroxy-2'-deoxyguanosine [8-OHdG]; oxidized low-density lipoprotein [LDL]) in older adults. Moderate to vigorous PA (MVPA) was estimated using a validated PA questionnaire in 26 older adults (mean [SD]; M/F = 9/17, age = 68 [4] y, body mass index = 26 [3] kg·m-2). Maximal oxygen consumption was estimated using the YMCA submaximal cycle test. Skeletal muscle endogenous antioxidants and serum 8-OHdG and oxidized LDL were measured. Bivariate and partial correlations (controlling for body mass index) were utilized to determine associations among variables. MVPA (1640 [1176]kcal·wk-1) was correlated with superoxide dismutase 2 (r = .55), catalase (r = .55), glutathione peroxidase 1 (r = .48), and 8-OHdG (r = -.41) (all Ps < .05), but not oxidized LDL. MVPA and 8-OHdG were not significantly correlated when controlling for body mass index (r = -.29). Estimated maximal oxygen consumption was correlated with glutathione peroxidase 1 (r = .48; P < .05). These data show that skeletal muscle endogenous antioxidant expression and circulating oxidative damage are associated with habitual MVPA in older adults. Thus, MVPA in older adults may be protective against reactive oxygen species damage due to higher expression of endogenous antioxidants.

Phytochemical Profile of Capsicum annuum L. cv Senise, Incorporation into Liposomes, and Evaluation of Cellular Antioxidant Activity

Overproduction of oxidants in the human body is responsible for oxidative stress, which is associated with several diseases. High intake of vegetables and fruits can reduce the risk of chronic diseases, as they are sources of bioactive compounds capable of contrasting the free radical effects involved in cancer, obesity, diabetes, and neurodegenerative and cardiovascular diseases. Capsicum annuum L. cv Senise is a sweet pepper that is grown in the Basilicata region (Italy). It is an important source of polyphenols, carotenoids, and capsinoids and can play a key role in human health. In this study, an ethanol extract was obtained from C. annuum dried peppers and the analysis of the phytochemical composition was performed by LC-ESI/LTQ Orbitrap/MS. The extract was incorporated into liposomes, which showed small size (~80 nm), good homogeneity, negative surface charge, and good stability in storage. The biological activity of the extract was evaluated in the human hepatoma (HepG2) cell line, used as model cells. The extract showed no cytotoxic activity and reduced the intracellular reactive oxygen species (ROS) level in stressed cells. The antioxidant activity was further improved when the extract was loaded into liposomes. Moreover, the extract promoted the expression of endogenous antioxidants, such as catalase, superoxide dismutase, and glutathione peroxidase through the Nrf-2 pathway evaluated by RT-PCR.

Knockout of the radical scavenger α1-microglobulin in mice results in defective bikunin synthesis, endoplasmic reticulum stress and increased body weight

α1-microglobulin (A1M) is a ubiquitous protein with reductase and radical- and heme-binding properties. The protein is mainly expressed in the liver and encoded by the α1-microglobulin-bikunin precursor (AMBP) gene together with the plasma proteinase inhibitor bikunin. The AMBP polypeptide is translated, glycosylated and the C-terminal bikunin part linked via a chondroitin sulfate glycosaminoglycan chain to one or two heavy chains in the endoplasmic reticulum (ER) and Golgi compartments. After proteolytic cleavage, the A1M protein and complexed bikunin parts are secreted separately. The complete physiological role of A1M, and the reason for the co-synthesis with bikunin, are both still unknown. The aim of this work was to develop an A1M knockout (A1M−KO) mouse model lacking expression of A1M, but with a preserved bikunin expression, and to study the phenotypic traits in these mice, with a focus on hepatic endoplasmic reticulum (ER) function. The bikunin expression was increased in the A1M−KO mouse livers, while the bikunin levels in plasma were decreased, indicating a defective biosynthesis of bikunin. The A1M−KO livers also showed an increased expression of transducers of the unfolded protein response (UPR), indicating an increased ER-stress in the livers. At twelve months of age, the A1M−KO mice also displayed an increased body weight, and an increased liver weight and lipid accumulation. Moreover, the KO mice showed an increased expression of endogenous antioxidants in the liver, but not in the kidneys. Together, these results suggest a physiological role of A1M as a regulator of the intracellular redox environment and more specifically the ER folding and posttranslational modification processes, particularly in the liver.