Production Of Oxygen Free Radicals Research Articles

Evaluation of Vitamin A and e levels in Chronic Renal Failure

Any atom or molecule that contains one or more unpaired electrons is defined as free radical, the most known reactive species. An unpaired electron is an electron that occupies an orbital alone, but electrons usually associate in pairs in orbital's of atoms and molecules. The present study focuses on the extent of free radical damage on lipid and Lipid peroxidation end products (measured as malondialdehyde, MDA) and effect on antioxidant defense mechanism (measured as vitamin E and vitamin C in the serum of CRF patients predialytically. The study was Carried in Sri Lakshmi narayana Institute of Medical Sciences, Pondicherry. 50 cases and 50 controls between age group of 30–60 were taken. Lipid peroxidation was measured in terms of MDA and antioxidants were measured as vitamin E and Vitamin C in serum of CRF patients before dialysis. The level of MDA, serum urea and Creatinine was significantly increased, antioxidant vitamin levels (C and E) were decreased in CRF patients as compared to normal subjects. Though there is evidence for production of oxygen free radicals in CRF, reports on net oxidative imbalance in the uremic state, as evidenced by increase in oxidant markers and decrease in antioxidant vitamins status in CRF patients. Oxidative injury generally takes place only when local oxidant production exceeds antioxidant defense.

The Possible Pathophysiological Outcomes and Mechanisms of Tourniquet-Induced Ischemia-Reperfusion Injury during Total Knee Arthroplasty.

Ischemia and reperfusion (I/R) injury induced by tourniquet (TQ) application leads to the release of both oxygen free radicals and inflammatory cytokines. The skeletal muscle I/R may contribute to local skeletal muscle and remote organ damage affecting outcomes after total knee arthroplasty (TKA). The aim of the study is to summarize the current findings associated with I/R injury following TKA using a thigh TQ, which include cellular alterations and protective therapeutic interventions. The PubMed database was searched using the keywords “ischemia reperfusion injury,” “oxidative stress,” “tourniquet,” and “knee arthroplasty.” The search was limited to research articles published in the English language. Twenty-eight clinical studies were included in this qualitative review. Skeletal muscle I/R reduces protein synthesis, increases protein degradation, and upregulates genes in cell stress pathways. The I/R of the lower extremity elevates local and systemic oxidative stress as well as inflammatory reactions and impairs renal function. Propofol reduces oxidative injury in this I/R model. Ischemic preconditioning (IPC) and vitamin C may prevent oxygen free radical production. However, a high dose of N-acetylcysteine possibly induces kidney injury. In summary, TQ-related I/R during TKA leads to muscle protein metabolism alteration, endothelial dysfunction, oxidative stress, inflammatory response, and renal function disturbance. Propofol, IPC, and vitamin C show protective effects on oxidative and inflammatory markers. However, a relationship between biochemical parameters and postoperative clinical outcomes has not been validated.

Influence of long-term per oral taurine treatment on activity of liver enzymes in mature rats

Taurine is sulfur-containing derivative of methionin and cysteine that plays a key role in glucose and lipid metabolism. Taurine regulates antioxidant defense system, membrane potential of mitochondria, and glycolysis. Thus, it might have a serious impact on cell metabolism in mammals. The aim of this work was to study the influence of long-term per oral taurine treatment (5, 10 and 20 mg/kg) on the antioxidant defense system, cholesterol content, activity of transaminases and lactate dehydrogenase in rat liver. To achieve that goal, mature Wistar rats (weight 140–160 g, age – 4 months) were divided in four groups – control, rats which once a day during 28 days were injected drinking water in esophagus, and three experimental groups, that were injected taurine solution in concentrations: І – 5 mg/kg, ІІ – 10 mg/kg and ІІІ – 20 mg/kg of body mass. After 28 days, rats were decapitated under light chloroform narcosis and liver mass was determined. In liver, content of cholesterol, TBA-active products and activity of antioxidant defense enzymes, transaminases, and lactate dehydrogenase were measured. Our results show that after a long-term per oral taurine treatment liver mass decreased by 27.5 % comparing to control group. Lactate dehydrogenase activity increased two times, while the activity of alanine aminotranferase and aspartate aminotransferase in mitochondrial fraction increased by 40–90 % in liver of animals of all experimental groups. Total activity of these enzymes in rat liver increased by 20–37 % in all experimental groups. Cholesterol content increased dy 32.4 % in rats of experimental group II. This may indicate intensification of liver metabolism. The content of TBA-active products in submitochondrial and mitochondrial fractions increased more than two times in rats of experimental groups II and III. The activity of superoxide dismutase in the submitochondrial fraction increased by 49.8 and 36.5 % in liver of that rats. The activation of superoxi­de dismutase and a rise in content of TBA-active products may suggest a rise of free oxygen radicals production and inability of antioxidant defense system. These results may indicate a negative influence of taurine in doses higher than 5 mg/kg, since the balance between antioxidant protection and lipid peroxidation processes was violated.

Altered gastrointestinal motility in an animal model of Lesch-Nyhan disease.

Mutations in the HGPRT1 gene, which encodes hypoxanthine-guanine phosphoribosyltransferase (HGprt), housekeeping enzyme responsible for recycling purines, lead to Lesch-Nyhan disease (LND). Clinical expression of LND indicates that HGprt deficiency has adverse effects on gastrointestinal motility. Therefore, we aimed to evaluate intestinal motility in HGprt knockout mice (HGprt¯). Spontaneous and neurally evoked mechanical activity was recorded in vitro as changes in isometric tension in circular muscle strips of distal colon. HGprt¯ tissues showed a lower in amplitude spontaneous activity and atropine-sensitivity neural contraction compared to control mice. The responses to carbachol and to high KCl were reduced, demonstrating a widespread impairment of contractility. L-NAME was not able in the HGprt¯ tissues to restore the large amplitude contractile activity typical of control. In HGprt¯ colon, a reduced expression of dopaminergic D1 receptor was observed together with the loss of its tonic inhibitory activity present in control-mice. The analysis of inflammatory and oxidative stress in colonic tissue of HGprt¯ mice revealed a significant increase of lipid peroxidation associated with over production of oxygen free radicals. In conclusion, HGprt deficiency in mice is associated with a decrease in colon contractility, not dependent upon reduction of acetylcholine release from the myenteric plexus or hyperactivity of inhibitory signalling. By contrast the increased levels of oxidative stress could partially explain the reduced colon motility in HGprt¯ mice. Colonic dysmotility observed in HGprt¯ mice may mimic the gastrointestinal dysfunctions symptoms of human syndrome, providing a useful animal model to elucidate the pathophysiology of this problem in the LND.

Hyperbaric oxygen therapy is not associated with oxidative stress assessed using plasma F2-isoprostanes and isofurans

Background and aimsHyperbaric oxygen (HBO) therapy is increasingly used in medical practice as a means of enhancing the formation of collagen matrix and angiogenesis, thus promoting healing in wounds and necrotic tissue. However, there are concerns that oxygen can also associate with increased production of oxygen free radicals and oxidative stress. F2-Isoprostanes (F2-IsoPs) formed by non-enzymatic oxidation of arachidonic acid (AA) are reliable measures for assessing oxidative stress in vivo. In addition, under conditions of high oxygen tension isofurans (IsoFs) are preferentially formed from AA and are considered to better reflect oxidative stress in the setting of high oxygen tension. This study aimed to measure plasma IsoFs and F2-IsoP in patients receiving HBO therapy to treat osteonecrosis secondary to radiation therapy. Our hypothesis was that IsoFs would continue to rise with increasing oxygen pressures in contrast to F2-IsoPs whose synthesis would be reduced. MethodsTwelve patients receiving hyperbaric therapy to treat osteonecrosis secondary to radiation therapy were studied during hyperbaric treatment. Blood samples were collected prior to, during and after cessation of HBO therapy that lasted for 119min. Seven serial blood samples were collected for measurement of plasma F2-IsoPs and IsoFs, blood gases and haemoglobin. ResultsOxygen saturation and venous oxygen partial pressure (PvO2) rose significantly during hyperbaric therapy. However, there were no significant changes in plasma IsoFs or F2-IsoPs during the hyperbaric therapy session. ConclusionIn this study of patients with osteonecrosis, HBO therapy at a maximum pressure of 2.4atm with up to 100% oxygen did not worsen oxidative stress assessed using plasma F2- IsoFs and IsoPs.

Triphenyl phosphonium coated nano-quercetin for oral delivery: Neuroprotective effects in attenuating age related global moderate cerebral ischemia reperfusion injury in rats

Cerebral ischemia–reperfusion is a classic example of reactive oxygen species (ROS) mediated acute damage to brain. Post-ischemic reperfusion induced oxygen free radicals production causes damage to brain cell mitochondria. Antioxidants like quercetin (Qc) have potentials to manage oxidative stress related pathophysiology. However low oral bioavailability and poor cell membrane permeability restrict its therapeutic efficacy. To overcome these hurdles mitochondria specific delivery of Qc nanocapsules was designed to efficiently counteract cerebral ischemia–reperfusion induced cell death and neurodegeneration in young and aged rats. The orally deliverable quercetin loaded polymeric nanocapsules (N1QC) were made mitochondria specific by using triphenylphosphonium cation as one of the matrix components. N1QC demonstrated higher brain uptake and remarkable mitochondrial localization post cerebral ischemia–reperfusion. This unique controlled mitochondrial delivery of quercetin ameliorated histopathological severity by preserving mitochondrial structural and functional integrity through sequestering ROS thus modulating mitochondrial ROS mediated apoptotic cell death in young and aged rats.

Pulmonary surfactant-associated proteins and inflammatory factors in obstructive sleep apnea.

Pulmonary surfactant (PS) plays roles in promoting the removal of the liquid, host defense, and immune regulation in the tracheal, bronchial, and alveoli epithelium. PS protein expression level can be regulated by oxygen levels and related free radicals. Obstructive sleep apnea (OSA) is featured with oxygen free radical production for damaging epithelial tissues and thus may affect PS production. The study was to explore the relationship between PS protein and OSA severity. We collected serum and bronchoalveolar lavage fluid (BALF) samples from 35 OSA patients and 22 healthy subjects. PS-associated proteins and inflammatory factors, including surfactant proteins, HIF-1α, NF-κB, and IL-6, were analyzed. Regression analysis was performed to reveal the relationship between biochemical factors and clinical indexes recorded during PSG monitor. Lower BALF and surfactant protein (except surfactant protein C or SPC) levels occurred in OSA patients (all p<0.05 compared to control group). A strongly negative correlation was found between surfactant protein with apnea-hypopnea index (AHI) and other sleeping indexes including ODI3 and ODI4. Similar patterns were found in serum samples, which were strongly correlated with BALF counterparts. Surfactant proteins were further found to have negative regression with inflammatory factors such as HIF-1α, NF-κB, and IL-6. This study established the relationship between PS-related protein with severity of OSA, plus their relationship with inflammatory factors. Our results provided possibly novel markers in general circulation for disease evaluation of OSA.

A review of the toxicity of nanoparticles to &amp;lt;italic&amp;gt;Daphnia magna&amp;lt;/italic&amp;gt;

With the wide production and usage of nanoparticles, nanotoxicity has received worldwide researches. As a model organism, Daphnia magna has been extensively used in the nanotoxicity studies. In this review, we overviewed research advance in the toxicity of nanoparticles to Daphnia magna , including acute toxicity, chronic toxicity, bioaccumulation, and the underlying mechanisms. Nanoparticles have dose-responsive acute toxicity to Daphnia manga and their toxicity is related to types of nanoparticles and culture media. Smaller nanoparticles generally have higher toxicity to Daphnia manga , presumably due to their easier transport through cell membranes. Due to polar functional groups and organic macromolecules are able to change surface properties of nanoparticles, most studies suggest that the acute toxicity of nanoparticles might be weakened by surface modification. High concentrations of nanoparticles can suppress the growth and reproduction of Daphnia manga . Bioaccumulation studies showed that nanoparticles could accumulate in Daphnia magna via water, feeding food, and absorbing through the skin. Since the concentration of nanoparticles, exposure time and cultivation media adopted in the studies varied greatly, the body burden and bioconcentration factor of nanoparticles were largely different, which makes it hard to compare accumulation capacity of Daphnia manga to different nanoparticles. At high exposure concentrations, accumulation amount of nanoparticles by Daphnia manga could reach µg/mg level. Although the toxicity mechanisms of nanoparticles to Daphnia manga have not been fully understood, below points are generally used to explain the toxicity: nanoparticle specific toxic, the release of toxic metal ions, and forming toxic complexes with other compounds. Nanoparticles and the release of metal ions can adhere and aggregate onto surfaces of Daphnia manga , causing the physical damage, membrane permeability changes, and cell function loss. They can also promote the production of the reactive oxygen species (ROS) and free radical, leading to lipid peroxidation, protein carbonylation and DNA damage. In addition, some nanoparticles themselves are not toxic, but can form complexes with toxic substance. At the end of text, we proposed several future research needs. First, compared with the experimental cultivation media, the physical and chemical properties of natural waters are obviously different, likely to cause big difference in the toxicity results. Therefore, realistic toxicity in natural waters needs to be studied. Second, the exposure concentrations of nanoparticles in chronic experiments are much higher than that in the real water environment, and the exposure time is also not long enough compared with practical condition. Lower concentrations and longer exposure time of nanoparticles are of great significance. Third, there is no unified approach in bioaccumulation experiments, making it difficult to compare and analyze the results from different labs. A standard test method established for the bioaccumulation test is thus required. Moreover, nanoparticles can remain in Daphnia magna and transfer to their offspring and other organisms though food chains. Hence, it is necessary to study the transformation, chronic toxicity, intergenerational transfer, and migration though food chains of nanoparticles. Lastly, up to date, toxicity mechanisms of nanoparticles to Daphnia manga have yet to reach a consensus. Nanoparticle characteristics, the growth status of Daphnia magna , culture medium compositions, toxicity experimental method, and many other factors might influence the judgment of the toxicity mechanisms. In order to better understand the toxic effects caused by nanoparticles, more researches are supposed to be done to find the impacts of these factors on the toxicity mechanisms.

E-cigarettes induce toxicological effects that can raise the cancer risk

Electronic cigarettes (e-cigs) are devices designed to deliver nicotine in a vaping solution rather than smoke and without tobacco combustion. Perceived as a safer alternative to conventional cigarettes, e-cigs are aggressively marketed as lifestyle-choice consumables, thanks to few restrictions and a lack of regulatory guidelines. E-cigs have also gained popularity among never-smokers and teenagers, becoming an emergent public health issue. Despite the burgeoning worldwide consumption of e-cigs, their safety remains largely unproven and it is unknown whether these devices cause in vivo toxicological effects that could contribute to cancer. Here we demonstrate the co-mutagenic and cancer-initiating effects of e-cig vapour in a rat lung model. We found that e-cigs have a powerful booster effect on phase-I carcinogen-bioactivating enzymes, including activators of polycyclic aromatic hydrocarbons (PAHs), and increase oxygen free radical production and DNA oxidation to 8-hydroxy-2′-deoxyguanosine. Furthermore, we found that e-cigs damage DNA not only at chromosomal level in peripheral blood, such as strand breaks in leucocytes and micronuclei formation in reticulocytes, but also at gene level such as point mutations in urine. Our results demonstrate that exposure to e-cigs could endanger human health, particularly among younger more vulnerable consumers.

Antioxidant and Antiproliferative Activities of an Ethylacetate Fraction of Picria Fel-Terrae Lour. Herbs

Background:Excessive production of oxygen free radicals and imbalance in the mechanisms responsible for antioxidant protection may result in the onset of many diseases including breast cancer.Objective:To evaluate antiproliferative and antioxidant activity of an ethylacetate fraction (EAF) of Picria fel-terrae Lour. Herbs in the T47D cell line.Methods:Phenolic and total flavonoid contents in EAF were determined. EAF was tested for cytotoxicity and effects on the cell cycle and apoptosis, as well as antioxidant activity.Results:EAF was found to contain high levels of phenolic agents (92.88 ± 0.50 mg GAE/g), total flavonoid (84.39 ± 0.07 mg QE/g). The EAF of Picria fel-terrae Lour. herbs was found to have an IC50 of 62.98µg/mL, caused accumulation in G0-G1 and S phase and increased early and late apoptosis. Antioxidant activity in DPPH assays gave an IC50 of 166.90 ± 0.10 µg/mL.Conclusions:The results reveal that EAF of Picria fel-terrae Lour. herbs has antiproliferative activity and strong antioxidant potential. Further studies are now needed to isolate the responsible antiproliferative and antioxidant components.

Effect of Antioxidants (β-mercaptoethanol and Cysteamine) on Assisted Reproductive Technology In vitro.

Oocyte Culture of Germinal Vesicle (GV) and its growth improves Assisted Reproductive Technology (ART) invitro and infertility. Inappropriate culture medium environment, low quality of oocytes, increase in Oxidative Stress (OS) events, Reactive Oxygen Species (ROS) and free radicals production are the main factors that result in unsuccessful Invitro Maturation (IVM) and decrease in reproduction. The present study was conducted with the aim to evaluate the effect of β-mercaptoethanol (BME) and Cysteamine (CYS) on IVM improvement, embryo fertilization and development of blastocyst of mouse immature oocyte. Oocytes were obtained from 4-6 weeks old Naval Medical Research Institute (NMRI) female mice, 48 hours after stimulation with Intraperitoneal (IP) injection of 10 IU Pregnant Mare Serum Gonadotropin (PMSG). GV oocyte with and without cumulus cells were isolated from ovaries and cultured in Tissue Culture Medium (TCM) 199 with availability of 100 μM of antioxidants (BME and CYS). After 24 hours, mature oocyte in metaphase II (MII) were fertilized with sperm in In vitro Fertilization (IVF) medium (T6) and evaluated for fetal development into blastocyst. BME and CYS could significantly (p<0.05) increase the rate of IVM and oocyte evolution, and embryo formation in medium culture. Furthermore, it is demonstrated that existence of Cumulus Oocyte Complexes (COC) significantly showed better IVM, fertilization and evolution trend as compared to oocytes without cumulus cover or Denuded Oocytes (DO), especially in TCM199 plus BME and CYS. So that the change in GV stage oocytes to MII (maturation rate), fertilization rates or 2PN formation, and two cell embryos formation or blastocyst development rate in the treatment group with addition of BME & CYS and COC was statistically significant as compared to the DO group (p-value < 0.0001). Both cellular and environmental factors could be important and involved in ART improvement.

LIPID PEROXIDE LEVELS AND ANTIOXIDANT STATUS IN HEALTHY AND ALCOHOLIC HEPATITIS PATIENTS

Background: Alcohol remains the single most significant cause of liver disease throughout the Western world, responsible for between 40 and 80% of cases of cirrhosis in different countries. Material & Methods:The study was conducted in Department of Biochemistry, Santosh medical college & Hospital, Ghaziabad and Veer Chandra Singh Garhwali Govt. Institute of Medical Sciences & Research, 164 alcoholic hepatitis patients were subjected to detailed clinical examination and laboratory investigations and the results were compared with 82controls. Blood samples were collected for oxidative stress parameters. It was observed that there was a significant increase in activities of Catalase, SOD, MDA, GPX and GR activity in patients with alcoholic hepatitis when compared to controls. Results: Results of our study show higher oxygen free radical production, evidenced by elevated levels of MDA and decreased levels of Catalase, SOD, GPx, GR, and TAS activity, supporting the evidence of oxidative stress in alcoholic hepatitis patients. Decreased concentrations of antioxidant support the hypothesis that alcoholic hepatitis is an important causative factor in pathogenesis of lipid peroxidation. Conclusion:Theantioxidant defense mechanisms might be impaired in patients with alcoholic hepatitis. These findings also provide a theoretical basis for development of novel therapeutic strategies, such as antioxidant supplementation. Key words: Alcoholic Hepatitis; Catalase;Glutathione Peroxidase; Glutathione Reductase; Malondialdehyde; Superoxide dismutase; Total antioxidant status.

Evaluation of In-vitro Antioxidant Activity of Ethanolic Extract of Ugli Fruit

Medicinal plants are rich sources of natural antioxidants which are used in the prevention and treatment of diseases like atherosclerosis, heart stroke, diabetes, cancer and to delay the process of aging. Antioxidants are the chemicals which scavenge the free radicals and help in preventing and treatment of several diseases. Human body produces oxygen free radicals and other reactive oxygen species (ROS) as by products through numerous physiological and biochemical processes. In the present study, antioxidant activity of rind extracts of Citrus reticulate x Citrus paradise (Ugli Fruit) was evaluated in vitro using DPPH, Nitric oxide, Hydrogen peroxide, Super oxide dismutase free radical scavenging methods. Different concentrations of test samples (ethanolic extracts) i.e. 50 µg/ml, 100 µg/ml, 250 µg/ml, 500 µg/ml and 1000 µg/ml were taken and each of the samples were analysed for their antioxidant status. Different concentrations of ethanolic extracts showed radical scavenging activity of which DPPH assay showed an IC50 value of about 18.9. The nitric oxide scavenging activity compared with Ascorbic acid and the IC50 values were found to be 46.59 µg/ml (Ascorbic acid) and 395.94 (Ugli fruit extract). The Ugli fruit extract was capable of scavenging hydrogenperoxide in a dose dependent manner. In superoxide dismutase assay, ascorbic acid is used as a standard and the ethanolic extract shows a better antioxidant property. Thus this study suggests that Citrus reticulate x Citrus paradise is an effective plant in terms of antioxidant potential that can be exploited for development of plant based antioxidant formulations.

Effects of cyclic nucleotide phosphodiesterases (PDEs) on mitochondrial skeletal muscle functions.

Mitochondria play a critical role in skeletal muscle metabolism and function, notably at the level of tissue respiration, which conduct muscle strength as well as muscle survival. Pathological conditions induce mitochondria dysfunctions notably characterized by free oxygen radical production disturbing intracellular signaling. In that way, the second messengers, cyclic AMP and cyclic GMP, control intracellular signaling at the physiological and transcription levels by governing phosphorylation cascades. Both nucleotides are specifically and selectively hydrolyzed in their respective 5'-nucleotide by cyclic nucleotide phosphodiesterases (PDEs), which constitute a multi-genic family differently tissue distributed and subcellularly compartmentalized. These PDEs are presently recognized as therapeutic targets for cardiovascular, pulmonary, and neurologic diseases. However, very few data concerning cyclic nucleotides and PDEs in skeletal muscle, specifically in mitochondria, are reported in the literature. The knowledge of PDE implication in mitochondrial signaling would be helpful for resolving critical mitochondrial dysfunctions in skeletal muscle.

Pharmacometabolomics for Predicting Variable Busulfan Exposure in Pediatric HSCT Patients

Optimal dosing for busulfan is important for minimization of systemic toxicity from overexposure and graft failure or relapse from underexposure. Herein, we investigated potential markers for predicting individual variation in the pharmacokinetics of busulfan, and suggested possible mechanism for inter-individual variability by using pharmacometabolomics.Fifty-nine pediatric patients undergoing busulfan-based conditioning chemotherapy for hematopoietic stem cell transplantation were divided into three groups according to the area under the concentration-time curve (AUC) of busulfan; low-, medium-, and high-AUC group. Nontargeted metabolic profiling of baseline urine samples showed that deferoxamine metabolites were abundant, while 2 acylcarnitines and phenylacetylglutamine were significantly lower in high-AUC group, compared with low-AUC group. Higher level of deferoxamine, an iron-chelating agent for the patients with a high serum ferritin level during the conditioning chemotherapy, suggested pharmacokinetic interaction between serum ferritin level and busulfan exposure. Retrospective analysis of the correlation between serum ferritin level and busulfan AUC showed positive correlation in 130 pediatric patients. The optimal busulfan dose to meet the target AUC of 18,750 μg*h/L/day was calculated to be 119.7 ± 30.1 mg/m2 in patients with ferritin < 1,000 ng/mL and 106.1 ± 29.3 mg/m2in patients with ferritin ≥ 1,000 ng/mL (P=0.021).Mechanismly, previous studies have indicated that ferritin, acylcarnitine and phenylacetylglutamine are closely associated with liver function. Increased serum ferritin is thought to be responsible for an increased production of oxygen free radicals and activation of GSH turnover, which means reduction of GSH levels in both plasma and erythrocytes and this depletion seems to be related to the decrease of busulfan metabolism. Down regulation of acylcarnitines is associated with deregulation of mitochondrial fatty acid β-oxidation by hepatic injury. PAGN, a marker of waste nitrogen scavenger, was down-regulated which indicates ammonia-related metabolism could also be involved in busulfan exposure. Hyperammonemia, a clinical condition of elevated ammonia levels, is mainly lead by liver cell damage.Taken together, our findings demonstrate that elevated serum ferritin levels are a potential biomarker correlated with busulfan exposure and provide some evidence that busulfan metabolism seems to decrease in the patients with reduced liver function. DisclosuresNo relevant conflicts of interest to declare.

Ovariectomy-Induced Mitochondrial Oxidative Stress, Apoptosis, and Calcium Ion Influx Through TRPA1, TRPM2, and TRPV1 Are Prevented by 17β-Estradiol, Tamoxifen, and Raloxifene in the Hippocampus and Dorsal Root Ganglion of Rats.

Relative 17β-estradiol (E2) deprivation and excessive production of mitochondrial oxygen free radicals (OFRs) with a high amount of Ca2+ influx TRPA1, TRPM2, and TRPV1 activity is one of the main causes of neurodegenerative disease in postmenopausal women. In addition to the roles of tamoxifen (TMX) and raloxifene (RLX) in cancer and bone loss treatments, regulator roles in Ca2+ influx and mitochondrial oxidative stress in neurons have not been reported. The aim of this study was to evaluate whether TMX and RLX interactions with TRPA1, TRPM2, and TRPV1 in primary hippocampal (HPC) and dorsal root ganglion (DRG) neuron cultures of ovariectomized (OVX) rats. Forty female rats were divided into five groups: a control group, an OVX group, an OVX+E2 group, an OVX+TMX group, and an OVX+RLX group. The OVX+E2, OVX+TMX, and OVX+RLX groups received E2, TMX, and RLX, respectively, for 14days after the ovariectomy. E2, ovariectomy-induced TRPA1, TRPM2, and TRPV1 current densities, as well as accumulation of cytosolic free Ca2+ in the neurons, were returned to the control levels by E2, TMX, and RLX treatments. In addition, E2, TMX, and RLX via modulation of TRPM2 and TRPV1 activity reduced ovariectomy-induced mitochondrial membrane depolarization, apoptosis, and cytosolic OFR production. TRPM2, TRPV1, PARP, and caspase-3 and caspase-9 expressions were also decreased in the neurons by the E2, TMX, and RLX treatments. In conclusion, we first reported the molecular effects of E2, TMX, and RLX on TRPA1, TRPM2, and TRPV1 channel activation in the OVX rats. In addition, we observed neuroprotective effects of E2, RLX, and TMX on oxidative and apoptotic injuries of the hippocampus and peripheral pain sensory neurons (DRGs) in the OVX rats. Graphical Abstract Possible molecular pathways of involvement of DEX in cerebral ischemia-induced apoptosis, oxidative stress, and calcium accumulation through TRPA1,TRPM2 and TRPV1 in the hippocampus and DRG neurons of rats. The N domain of the TRPM2 contains ADP-ribose (ADPR) pyrophosphate enzyme, which is separately activated by ADPR and oxidative stress, although the channel is reversibly inhibited by N-(p-amylcinnamoyl) anthranilic acid (ACA). The TRPV1 is also activated by mitochondrial oxidative stress and capsaicin, and it is blocked by capsazepine (CPZ). TRPA1 is also activated by oxidative stress it is inhibited by AP18. Increased cytosolic Ca2+ concentration through TRPA1,TRPM2 and TRPV1 in ovariectomized (OVX) rats may lead to neuronal toxicity, reactive oxygen species (ROS) processes, and eventual cell death. 17β-Estradiol (E2), tamoxifen (TMX), and raloxifene (RLX) reduced oxidative stress, apoptosis (including caspase-3 and caspase-9), mitochondrial membrane depolarization, and Ca2+ influx through the inhibition of TRPA1,TRPM2 and TRPV1 activation.

Implicaciones hemodinámicas y renales de los inhibidores del cotransportador sodio-glucosa tipo 2 en el contexto de la diabetes mellitus tipo 2

In DM2, there is increased expression of the proximal glucose transporter SGLT2. The increased glucose reabsorption from the urine to the proximal tubule and subsequently to the bloodstream, has three direct effects on the prognosis of patients with DM2: a) it increases the daily glucose load by raising the renal threshold for glucose, thus augmenting requirements for oral antidiabetics and insulin. This progressive increase occurs throughout the course of the disease and in parallel with the increase in renal mass (renal hypertrophy); b) because of the greater glucose reabsorption, glycosuria is lower than the level corresponding to glycaemia, decreasing the stimulus on the tubuloglomerular feedback system of the distal nephron. As a result, the glomerular vasodilation caused by hyperglycaemia is not arrested, maintaining glomerular hyperfiltration, and c) the excess glucose transported to the proximal tubular cells modifies their redox status, increasing local production of glycosylating products and activating local production of proinflammatory and profibrotic proliferative mediators. These mediators are responsible for the direct free radical damage to proximal tubular cells, for increased SGLT2 expression, increased production of collagen IV and extracellular matrix, and activation of monocyte/macrophages able to cause endothelial injury. The use of SGLT2 inhibitors not only reduces the reabsorption of glucose from the glomerular filtrate back into the circulationthus improving metabolic control in diabetesbut also restores tubuloglomerular feedback by increasing glycosuria and distal urinary flow. However, the most notable effect is due to inhibition of glucose entry to the proximal tubular cells. Glycosuria is toxic to the kidney: it harms glucosetransporting cells, that is, the proximal cells, which contain SGLT2. In animal models, SGLT2 inhibition reduces local production of oxygen-free radicals, the formation of mesangial matrix and collagen IV, glomerular infiltration by inflammatory cells and monocyte/macrophage-dependent arteriosclerosis. In humans, SGLT2 have a demonstrated ability to reduce renal injury and cardiovascular risk in patients with type 2 diabetes mellitus.

Preventive and therapeutic application of molecular hydrogen in situations with excessive production of free radicals.

Excessive production of oxygen free radicals has been regarded as a causative common denominator of many pathological processes in the animal kingdom. Hydroxyl and nitrosyl radicals represent the major cause of the destruction of biomolecules either by a direct reaction or by triggering a chain reaction of free radicals. Scavenging of free radicals may act preventively or therapeutically. A number of substances that preferentially react with free radicals can serve as scavengers, thus increasing the internal capacity/activity of endogenous antioxidants and protecting cells and tissues against oxidative damage. Molecular hydrogen (H(2)) reacts with strong oxidants, such as hydroxyl and nitrosyl radicals, in the cells, that enables utilization of its potential for preventive and therapeutic applications. H(2) rapidly diffuses into tissues and cells without affecting metabolic redox reactions and signaling reactive species. H(2) reduces oxidative stress also by regulating gene expression, and functions as an anti-inflammatory and anti-apoptotic agent. There is a growing body of evidence based on the results of animal experiments and clinical observations that H(2) may represent an effective antioxidant for the prevention of oxidative stress-related diseases. Application of molecular hydrogen in situations with excessive production of free radicals, in particular, hydroxyl and nitrosyl radicals is relatively simple and effective, therefore, it deserves special attention.

Selenium Source Impacts Protection of Porcine Jejunal Epithelial Cells from Cadmium-Induced DNA Damage, with Maximum Protection Exhibited with Yeast-Derived Selenium Compounds.

Selenium (Se) is found in inorganic and organic forms, both of which are commonly used in animal feed supplements. The aim of this study was to determine the impact of the chemical form of Se on its associated ameliorative effects on cadmium (Cd)-induced DNA damage in a porcine model. At a cellular level, Cd mediates free oxygen radical production leading in particular to DNA damage, with consequential mutagenesis and inhibition of DNA replication. In this study, porcine jejunal epithelial cells (IPEC-J2) were pre-incubated for 48h with one of Se-yeast (Sel-Plex), selenomethionine (Se-M), sodium selenite (Se-Ni) or sodium selenate (Se-Na). The effects of this supplementation on cell viability and DNA damage following cadmium chloride (CdCl2) exposure were subsequently evaluated. IPEC-J2 cells were cultivated throughout in medium supplemented with porcine serum to generate a superior model that recapitulated the porcine gut epithelium. The results illustrated that Se antioxidant effects were both composition- and dose-dependent as evident from cell viability (Alamar Blue and 5-carboxyfluorescein diacetate acetoxymethyl ester) and DNA damage assays (Comet and TUNEL). Both the Se-yeast and Se-M organic species, when used at the European Food Safety Authority guideline levels, had a protective effect against Cd-induced DNA damage in the IPEC-J2 model system whereas for inorganic Se-Ni and Se-Na sources no protective effects were observed and in fact these were shown to enhance the negative effects of Cd-induced DNA damage. It can be concluded that nutritional supplementation with organoselenium may protect porcine gut integrity from damage induced by Cd.

Oxidative stress in otosclerosis

Objectives: Otosclerosis is a disease involving abnormal bone turnover in the human otic capsule that results in hearing loss. Several hypotheses have been suggested for the etiopathogenesis of otosclerosis; however, its etiology remains unclear.Methods: This study evaluated the correlation between otosclerosis and levels of paraoxonase-1 (PON1), arylesterase, total antioxidant status, total oxidant status (TOS), oxidative stress index (OSI), total sulfhydryl (-SH) groups, lipid hydroperoxide, and ceruloplasmin in the serum of otosclerosis patients and healthy subjects with respect to oxidative stress.Results: In our study, TOS and OSI levels were higher in the otosclerosis patients than in the controls. The PON1 levels showed that oxidative stress was severe, and as a result, antioxidants were consumed and depleted.Discussion: When an imbalance between oxygen free radical production and antioxidative defense mechanisms occurs, reactive oxygen species levels may increase, which in turn may damage cells and tissues through the peroxidation of phospholipid membrane structures. The body initially responds with increased antioxidant production, but if the oxidative stress is severe, decreased antioxidant levels may result. This study reports expression levels of oxidative stress species in otosclerosis patients.