Towards in vivo photomediated delivery of anticancer peptides: Insights from pharmacokinetic and -dynamic data

An in vivo study of a photoswitchable cytotoxic peptide LMB040 has been undertaken on a chemically induced hepatocellular carcinoma model in immunocompetent rats. We analysed the pharmacokinetic profile of the less toxic photoform ("ring-closed" dithienylethene) of the compound in tumors, plasma, and healthy liver. Accordingly, the peptide can reach a tumor concentration sufficiently high to exert a cytotoxic effect upon photoconversion into the more active ("ring-open") photoform. Tissue morphology, histology, redox state of the liver, and hepatic biochemical parameters in blood serum were analysed upon treatment with (i) the less active photoform, (ii) the in vivo light-activated alternative photoform, and (iii) compared with a reference chemotherapeutic 5-fluorouracil. We found that application of the less toxic form followed by a delayed in vivo photoconversion into the more toxic ring-open form of LMB040 led to a higher overall survival of the animals, and signs of enhanced immune response were observed compared to the untreated animals.

The effect of water-soluble pristine C60 fullerene on 6-OHDA-induced Parkinson’s disease in rats

Oxidative stress is thought to be one of the mechanisms that leads to the dysfunction and degeneration of dopaminergic neurons in Parkinson’s disease pathogenesis and presumed to be underway during the prodromal phase. Therefore, therapy, which is effective against pre-motor symptoms, might be effective in preventing or delaying the development and progression of Parkinson’s disease. The aim of our study was to investigate the therapeutic efficiency of pristine C60 fullerene aqueous solution (C60FAS) during Parkinson’s disease in rats. The unilateral dopamine deficiency was induced in male Wistar rats (220–250 g) by stereotaxic microinjection of neurotoxin 6-hydroxydopamine (6-OHDA, 12 μg). C60FAS was injected to rats intraperitoneally daily for 10 days (0.65 mg/kg per day). The percentage of destroyed dopaminergic neurons was determined by the apomorphine test and by IHC staining of tyrosine hydroxylase-positive neurons in substantia nigra. We evaluated the rat body weight, the water and food intake, Open Field behavioural test, the level of biochemical antioxidant system, the activity of peritoneal macrophages. Levels of spontaneous and carbachol-stimulated colon motility were estimated by ballonographic method in vivo. C60FAS showed a positive tendency to increase the number of tyrosine hydroxylase-positive cells in the midbrain, which was associated with more profound improvement in apomorphine-rotation behaviour and slight relief of the anxiety level in Open Field test. Furthermore, C60FAS treatment increased the index of stimulated distal colon motor activity while it did not have a significant effect on water content in feces and total gastrointestinal transit time. C60FAS treatment did not affect water intake behaviour or body weight changes while it induced an increase of glutathione level and decrease activity of glutathione peroxidase in the brain as well as an increase in activity of peritoneal macrophages in 6-OHDA-Parkinson’s disease rats. These findings confirmed the potential therapeutic effectiveness of water-soluble pristine C60 fullerene in Parkinson’s disease pathogenesis, though there is ground for caution because of its systemic mild toxic effect.

Effects induced by a 50 Hz electromagnetic field and doxorubicin on Walker-256 carcinosarcoma growth and hepatic redox state in rats

We compare the effects of an extremely low-frequency electromagnetic field (EMF) with the chemotherapeutic agent doxorubicin (DOX) on tumor growth and the hepatic redox state in Walker-256 carcinosarcoma-bearing rats. Animals were divided into five groups with one control (no tumor) and four tumor-bearing groups: no treatment, DOX, DOX combined with EMF and EMF. While DOX and DOX + EMF provided greater inhibition of tumor growth, treatment with EMF alone resulted in some level of antitumor effect (p < .05). Superoxide dismutase, catalase activity and glutathione content were significantly decreased in the liver of tumor-bearing animals as compared with the control group (p < .05). The decreases in antioxidant defenses accompanied histological findings of suspected liver damage. However, hepatic levels of thiobarbituric acid reactive substances, an indicator of lipid peroxidation, were three times lower in EMF and DOX + EMF groups than in no treatment and DOX (p < .05). EMF and DOX + EMF showed significantly lower activity of serum ALT than DOX alone (p < .05). These results indicate that EMF treatment can inhibit tumor growth, causing less pronounced oxidative stress damage to the liver. Therefore, EMF can be used as a therapeutic strategy to influence the hepatic redox state and combat cancer with reduced side-effects.

African Vegetables (Clerodendrum volibile Leaf and Irvingia gabonensis Seed Extracts) Effectively Mitigate Trastuzumab-Induced Cardiotoxicity in Wistar Rats

Trastuzumab (TZM) is a humanized monoclonal antibody that has been approved for the clinical management of HER2-positive metastatic breast and gastric cancers but its use is limited by its cumulative dose and off-target cardiotoxicity. Unfortunately, till date, there is no approved antidote to this off-target toxicity. Therefore, an acute study was designed at investigating the protective potential and mechanism(s) of CVE and IGE in TZM-induced cardiotoxicity utilizing cardiac enzyme and oxidative stress markers and histopathological endpoints. 400 mg/kg/day CVE and IGE dissolved in 5% DMSO in sterile water were investigated in Wistar rats injected with 2.25 mg/kg/day/i.p. route of TZM for 7 days, using serum cTnI and LDH, complete lipid profile, cardiac tissue oxidative stress markers assays, and histopathological examination of TZM-intoxicated heart tissue. Results showed that 400 mg/kg/day CVE and IGE profoundly attenuated increases in the serum cTnI and LDH levels but caused no significant alterations in the serum lipids and weight gain pattern in the treated rats. CVE and IGE profoundly attenuated alterations in the cardiac tissue oxidative stress markers' activities while improving TZM-associated cardiac histological lesions. These results suggest that CVE and IGE could be mediating its cardioprotection via antioxidant, free radical scavenging, and antithrombotic mechanisms, thus, highlighting the therapeutic potentials of CVE and IGE in the management of TZM-mediated cardiotoxicity.

Water-Soluble Pristine C60 Fullerene Inhibits Liver Alterations Associated with Hepatocellular Carcinoma in Rat

Excessive production of reactive oxygen species is the main cause of hepatocellular carcinoma (HCC) initiation and progression. Water-soluble pristine C₆₀ fullerene is a powerful and non-toxic antioxidant, therefore, its effect under rat HCC model and its possible mechanisms were aimed to be discovered. Studies on HepG2 cells (human HCC) demonstrated C₆₀ fullerene ability to inhibit cell growth (IC₅₀ = 108.2 μmol), to induce apoptosis, to downregulate glucose-6-phosphate dehydrogenase, to upregulate vimentin and p53 expression and to alter HepG2 redox state. If applied to animals experienced HCC in dose of 0.25 mg/kg per day starting at liver cirrhosis stage, C₆₀ fullerene improved post-treatment survival similar to reference 5-fluorouracil (31 and 30 compared to 17 weeks) and inhibited metastasis unlike the latter. Furthermore, C₆₀ fullerene substantially attenuated liver injury and fibrosis, decreased liver enzymes, and normalized bilirubin and redox markers (elevated by 1.7–7.7 times under HCC). Thus, C₆₀ fullerene ability to inhibit HepG2 cell growth and HCC development and metastasis and to improve animal survival was concluded. C₆₀ fullerene cytostatic action might be realized through apoptosis induction and glucose-6-phosphate dehydrogenase downregulation in addition to its antioxidant activity.

Clerodendrum volubile Ethanol Leaf Extract: A Potential Antidote to Doxorubicin-Induced Cardiotoxicity in Rats

Doxorubicin is widely applied in hematological and solid tumor treatment but limited by its off-target cardiotoxicity. Thus, cardioprotective potential and mechanism(s) of CVE in DOX-induced cardiotoxicity were investigated using cardiac and oxidative stress markers and histopathological endpoints. 50–400 mg/kg/day CVE in 5% DMSO in distilled water were investigated in Wistar rats intraperitoneally injected with 2.5 mg/kg DOX on alternate days for 14 days, using serum troponin I and LDH, complete lipid profile, cardiac tissue oxidative stress marker assays, and histopathological examination of DOX-treated cardiac tissue. Preliminary qualitative and quantitative assays of CVE's secondary metabolites were also conducted. Phytochemical analyses revealed the presence of flavonoids (34.79 ± 0.37 mg/100 mg dry extract), alkaloids (36.73 ± 0.27 mg/100 mg dry extract), reducing sugars (07.78 ± 0.09 mg/100 mg dry extract), and cardiac glycosides (24.55 ± 0.12 mg/100 mg dry extract). 50–400 mg/kg/day CVE significantly attenuated increases in the serum LDH and troponin I levels. Similarly, the CVE dose unrelatedly decreased serum TG and VLDL-c levels without significant alterations in the serum TC, HDL-c, and LDL-c levels. Also, CVE profoundly attenuated alterations in the cardiac tissue oxidative stress markers' activities while improving DOX-associated cardiac histological lesions that were possibly mediated via free radical scavenging and/or antioxidant mechanisms. Overall, CVE may play a significant therapeutic role in the management of DOX-induced cardiotoxicity in humans.

Water-Soluble Pristine C60 Fullerenes Inhibit Liver Fibrotic Alteration and Prevent Liver Cirrhosis in Rats

Liver cirrhosis is an outcome of a wide range of liver chronic diseases. It is attributed to oxidative stress; therefore, antioxidant usage could be a promising treatment of that. So, exploring the impact of effective free radical scavenger pristine C₆₀ fullerenes on liver fibrosis and cirrhosis and their ability to interact with main growth factor receptors involved in liver fibrogenesis was aimed to be discovered. We used N-diethylnitrosamine/carbon tetrachloride-induced simulations of rat liver fibrosis (10 weeks) and cirrhosis (15 weeks). Pristine C₆₀ fullerene aqueous colloid solution (C₆₀FAS) was injected daily at a dose of 0.25 mg/kg throughout the experiment. Liver morphology and functional and redox states were assessed. C₆₀ fullerenes' ability to interact with epidermal, vasoendothelial, platelet-derived, and fibroblast growth factor receptors (EGFR, VEGFR, PDGFR, and FGFR, respectively) was estimated by computational modeling. We observed that C₆₀FAS reduced the severity of fibrosis in fibrotic rats (0.75 vs. 3.0 points according to Ishak score), attenuated the hepatocyte injury, normalized elevated blood serum alkaline phosphatase (ALP) and lactate dehydrogenase (LDH), and mitigated oxidative stress manifestation in liver tissue restoring its redox balance. When applied to cirrhotic animals, C₆₀FAS reduced connective tissue deposition as well (2.4 vs. 5.4 points according to Ishak score), diminished ALP and LDH (by 16% and 61%), and normalized conjugated and nonconjugated bilirubin, restoring the liver function. Altered liver lipid and protein peroxides and glutathione peroxidase activity were also leveled. Within a computer simulation, it was shown that C₆₀ fullerenes can block hinge prohibiting ATP binding for EGFR and FGFR and thus blocking associated signal pathways. This ability in addition to their antioxidant properties may contribute to C₆₀ fullerene's antifibrotic action. Thus, C₆₀FAS may have a substantial therapeutic potential as an inhibitor of liver fibrosis and cirrhosis.

Sulfobacillus thermotolerans: new insights into resistance and metabolic capacities of acidophilic chemolithotrophs

The first complete genome of the biotechnologically important species Sulfobacillus thermotolerans has been sequenced. Its 3 317 203-bp chromosome contains an 83 269-bp plasmid-like region, which carries heavy metal resistance determinants and the rusticyanin gene. Plasmid-mediated metal resistance is unusual for acidophilic chemolithotrophs. Moreover, most of their plasmids are cryptic and do not contribute to the phenotype of the host cells. A polyphosphate-based mechanism of metal resistance, which has been previously unknown in the genus Sulfobacillus or other Gram-positive chemolithotrophs, potentially operates in two Sulfobacillus species. The methylcitrate cycle typical for pathogens and identified in the genus Sulfobacillus for the first time can fulfill the energy and/or protective function in S. thermotolerans Kr1 and two other Sulfobacillus species, which have incomplete glyoxylate cycles. It is notable that the TCA cycle, disrupted in all Sulfobacillus isolates under optimal growth conditions, proved to be complete in the cells enduring temperature stress. An efficient antioxidant defense system gives S. thermotolerans another competitive advantage in the microbial communities inhabiting acidic metal-rich environments. The genomic comparisons revealed 80 unique genes in the strain Kr1, including those involved in lactose/galactose catabolism. The results provide new insights into metabolism and resistance mechanisms in the Sulfobacillus genus and other acidophiles.

Antioxidant defenses at enzymatic and transcriptional levels in response to acute lead administration in Oxya chinensis

Lead (Pb) is known to be toxic to many organisms. Oxidative stress is a major mechanism of its toxicity. This research aims to investigate the effects of Pb on hydrogen peroxide (H₂O₂) and malonedialdehyde (MDA) contents, activities and mRNA levels of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)) after Oxya chinensis were acutely treated with lead acetate for 24 h. The results showed that the LD₅₀-24 h value of lead acetate to O. chinensis was 1541.89 (1431.19-1655.77) μg g^-1 body H₂O₂ and MDA contents were elevated after Pb administration, which suggested that Pb induced the overproduction of ROS and caused oxidative stress. SOD activities were significantly inhibited 40.42% of the control by 280 μg μL^-1 Pb. CAT activities were increased while GPx activities had no significant changes. Different types of antioxidant-related genes had various responses to Pb stress. The transcriptions of icCuZnSOD2 and ecCuZnSOD2 were significantly inhibited by different concentrations of Pb. MnSOD mRNA levels showed the concentration-dependent rise with the Pb concentrations increase. The expressions of ecCuZnSOD1, CAT1, and GPx were significantly up-regulated while the transcriptions of icCuZnSOD1 and CAT2 had no significant changes. Alteration of activities and mRNA expressions of antioxidant enzymes implied that Pb-induced antioxidant defenses were related to modifications at enzymatic and transcriptional levels. The profiles of antioxidant enzymes and H₂O₂ and MDA contents and relationships among the parameters indicated that the cooperation of multiple antioxidants rather than a single factor might be responsible for the antioxidant defenses against Pb stress.

Plasma Total Antioxidant Capacity and Activities of Blood Glutathione Peroxidase and Superoxide Dismutase Determined in Healthy Dogs by Using Commercially Available Kits

Data on the values of selected blood antioxidant parameters, i.e. total antioxidant capacity, glutathione peroxidase, and superoxide dismutase in healthy dogs, are lacking. There are no published accepted standard reference methods for their determination. The aim of this study was to determine the values of plasma total antioxidant capacity and the activities of whole blood glutathione peroxidase and erythrocyte superoxide dismutase in 30 healthy client-owned dogs (19 females, 11 males). The effect of age and sex on the measured antioxidant parameters was also investigated. Antioxidant parameters were determined with an automated biochemical analyser, using the commercially available Randox kits. No significant difference in age, weight, and antioxidant parameters was determined between females and males. A significant positive effect of age (p = 0.002, r2 = 0.284) on superoxide dismutase activity was confirmed. There was no effect of sex on any of the antioxidant parameters measured. However, we observed a tendency of the effect of sex (p = 0.063, r2 = 0.118), as well as age (p = 0.073, r2 = 0.111), on the activity of glutathione peroxidase. Our results are in part comparable with the results of other studies in which the same types of methods and samples were used to determine antioxidant parameters. In conclusion, the sex and age of dogs should be taken into consideration when planning a study on antioxidant status parameters.

Cr (VI) induced oxidative stress and toxicity in cultured cerebellar granule neurons at different stages of development and protective effect of Rosmarinic acid

Chromium (Cr) is a widespread metal ion in the workplace, industrial effluent, and water. The toxicity of chromium (VI) on various organs including the liver, kidneys, and lung were studied, but little is known about neurotoxicity. In this study, neurotoxic effects of Cr (VI) have been investigated by cultured cerebellar granule neurons (CGNs). Immature and mature neurons were exposed to different concentrations of potassium dichromate for 24 h and cytotoxicity was measured by MTT assay. In addition, immature neurons were exposed for 5 days as regards cytotoxic effect in development stages. The reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and the protective effect of Rosmarinic acid on mature and immature neurons exposed to potassium dichromate, were measured. Furthermore, lipid peroxidation, glutathione peroxidase (GPx), and acetylcholinesterase activity in mature neurons were assessed following exposure to potassium dichromate. The results indicate that toxicity of Cr (VI) dependent on maturation steps. Cr (VI) was less toxic for immature neurons. Also, Cr (VI) induced MMP reduction and ROS production in both immature and mature neurons. In Cr (VI) treated neurons, increased lipid peroxidation and GPx activity but not acetylcholinesterase activity was observed. Interestingly, Rosmarinic acid, as a natural antioxidant, could protect mature but not immature neurons against Cr (VI) induced toxicity. Our findings revealed vulnerability of mature neurons to Cr (VI) induced toxicity and oxidative stress.

Effects of ozone oxidative preconditioning on different hepatic biomarkers of oxidative stress in endotoxic shock in mice

In endotoxic shock, variations are known to occur in different biochemical parameters of oxidative stress. Ozone oxidative preconditioning (OOP) is a good candidate to restore the redox balance on different tissue. This investigation examined the effect of OOP on different biomarkers of oxidative stress in hepatic tissue of mice treated with lipopolysaccharide (LPS). LPS doses of 30 mg/kg were administered intraperitoneally (i.p.) and pretreatment with ozone/oxygen mixture (OOM) was applied i.p. at 0.2, 0.4, and 1.2 mg/kg once daily during 5 days before LPS injection. The mice were euthanized under ether atmosphere at different times, 1 and 24 h after LPS injection. Hepatic tissue from all animals was taken for biochemical determinations of oxidative stress parameters such as thiobarbituric acid reactive substances (TBARS) content and activity of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST). The results demonstrated that OOP reduces levels of TBARS content and increases the activity of GPx in hepatic tissue. In conclusion, OOP was able to recover the redox balance and in this way to protect the animals against the oxidative damage induced by endotoxemia.

Effect of ozone/oxygen mixture on systemic oxidative stress and organic damage

Ozone is a molecule of high energetic content. Its great oxidative power has been used in medicine for the treatment of several illnesses with a wide spectrum. The rectal insufflation with a mixture of ozone/oxygen is considered as a simple therapy, not painful, of low cost and practically free from adverse effects. Given its potential oxidation and lack of side-effects, the objective has been to know the state of different indexes of redox state in blood which may contribute to understanding the mechanism by which mixtures of ozone/oxygen administered by intrarectal route are able to exert actions on other organs. With this purpose female rabbits were used, distributed into four groups, and three doses of ozone/oxygen mixture were tested. When treatment was finished, the determination of pro-oxidant and antioxidant markers was carried out. Also indexes of organic damage were determined. Ozone doses administered to rabbits did not cause adverse effects and mortality did not show significant changes relative to tissue damages and they increased enzymes activities belonging to the first line antioxidant defences. The results demonstrate that ozone/oxygen mixture administered by rectal insufflations is innocuous and it is able to increase the antioxidant defense of the organism.

Hyperoxygenated solution: effects on acute hypobaric hypoxia-induced oxidative damage in rabbits

High altitude (HA) exposure disrupts the efficiency of the antioxidant system and can lead to oxidative damage in various organs and tissues. The present study investigated the effect of hyperoxygenated solution (HOS) intravenous infusion therapy on oxidative damage induced by acute hypobaric hypoxia. Experimental rabbits were exposed to a simulated high altitude (HA), equivalent to 8500 m, in an animal decompression chamber for 3 h. HOS infusion attenuated the rise in malondialdehyde (MDA) levels and the decrease of the reduced oxidized glutathione (GSH/GSSG) ratio. HOS also increased the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px); the arterial partial pressure of oxygen (Pao(2)); and arterial blood oxygen saturation (Sao(2)) levels. Animals treated with HOS had higher Pao(2) compared with those subjected to airway oxygen therapy (p < 0.01) during HA exposure. These observations suggest that HOS intravenous infusion exerts protective effects against acute hypobaric hypoxia-induced oxidative damage.

Preconditioning with ozone/oxygen mixture induces reversion of some indicators of oxidative stress and prevents organic damage in rats with fecal peritonitis

OBJECTIVE AND DESIGN

Reactive oxygen and nitrogen species are involved in the pathogenesis of sepsis syndrome with peritonitis and the septic shock. The aim of this study was to determine whether ozone oxidative preconditioning (OOP) may exert beneficial effects in the prevention and treatment of sepsis syndrome in rats inoculated by the intraperitoneal route (i.p.) with fecal material and also to determine if antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx) may exert protective effects against this systemic inflammatory disorder.

MATERIALS AND METHODS

Male Wistar rats were used. SOD and GPx activities were determined in erythrocytes. Thiobarbituric acid reactive substances (TBARS) content as biomarkers of oxidative stress, alanine amino transferase (ALT), aspartate amino transferase (AST) and creatinine (CRE) were measured in blood serum and myeloperoxidase (MPO) in lung tissue as markers of organs damage.

RESULTS

In rats submitted to OOP, SOD and GPx activities were significantly increased and it was accompanied by significant decrease of TBARS content in blood serum. OOP also significantly reduced levels of ALT, AST and CRE in blood serum as well as MPO in rat lung.

CONCLUSION

The results support the important role of SOD and GPx in the protective effects of OOP against organ damage induced by fecal peritonitis in rats.

Antioxidant mechanism is involved in the gastroprotective effects of ozonized sunflower oil in ethanol-induced ulcers in rats

This research was performed in order to determine the potential protective effects of ozonized sunflower oil (OSO) in the injury of rat gastric mucosa induced by absolute ethanol and as well as to elucidate the role of reactive oxygen species (ROS), lipid peroxidation, and some important constituents of antioxidant defense such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in these effects. OSO was administered to rats intragastrically by a cannula and it was applied during four days to animals. The doses of OSO administered daily to each group of rats were 4, 12, and 24 mg/kg, respectively, and one hour after the last treatment, absolute ethanol (1 mL/200 mg body weight) was administered. Our results showed that gastric ulcer index was significantly reduced in rats pretreated with OSO as compared with ethanol-treated controls. However, in rats pretreated with OSO, no significant reduction of TBARS content in gastric mucosa was found as compared to those rats treated with ethanol alone. In contrast, SOD and GSH-Px activities were significantly increased in gastric mucosa of OSO-pretreated rats with respect to those treated with ethanol alone. In summary, our results demonstrate that OSO pretreatment exerts protective effects in ethanol-induced gastric ulcers in rats. Furthermore, these results provide evidence that these protective effects of OSO are mediated at least partially by stimulation of some important antioxidant enzymes such as SOD and GSH-Px, which are scavengers of ROS and therefore prevent gastric injury induced by them.

Ozone therapy effects on biomarkers and lung function in asthma

BACKGROUND

The relationship and behavior of serum immunoglobulin E (IgE) level, peripheral blood mononuclear cell (PBMC) human leukocyte antigen DR (HLA-DR) expression and erythrocyte glutathione antioxidant pathway in asthma patients treated with systemic ozone therapy have not been studied before.

METHODS

Asthma patients were treated about 1 year with three cycles (5 or 6 months each) with three different ozone therapy protocols. Ozone major autohemotherapy (MAHT) was applied at doses of 4 and 8 mg, 15 sessions each cycle; and ozone rectal insufflations (RI) at a dose of 10 mg, 20 sessions each cycle. Serum IgE, HLA-DR expression in PBMC and biomarkers for antioxidant pathway were measured before and at the end of each cycle. Lung function and symptoms test were recorded at the beginning and after the third cycle.

RESULTS

IgE and HLA-DR decreased with the three types of treatments, while increments in reduced glutathione, glutathione peroxidase, glutation reductase and glutathione S-transferase were achieved with all treatments. Lung function and symptoms test were markedly improved. However, in all parameters the best response was obtained in the order: MAHT at 8 mg better than MAHT at 4 mg better than RI at 10 mg. Before ozone treatment, glutathione antioxidant parameters were under the normal reference values, suggesting the occurrence of oxidative stress associated with atopic asthma.

CONCLUSIONS

This study demonstrates the effectiveness of ozone therapy in reducing IgE and inflammatory mediators along with the induction of antioxidant elements. The study raises the role of systemic ozone therapy in atopic asthma by means of its immunomodulatory and oxidative stress regulation properties.

A critical assessment of some biomarker approaches linked with dietary intake

In this review many examples are given of the complexities involved in using some biomarkers in relation to assessing the effects of dietary exposure, when there is frequently a need to determine changes following long-term low level exposure to dietary components. These range from understanding why the biomarker might be valuable and how best it can be measured, to the pitfalls which can occur in the interpretation of data. Analytical technique is considered in relation to folate and selenium, and flavonoid and carotenoid species are used to illustrate how the metabolism of a compound may alter the validity or adequacy of a marker. Vitamin A is discussed in relation to the difficulties which can arise when there are several biomarkers that may be available to assess exposure to one nutrient. Vitamin B12 is discussed in relation to the dietary choices made by individuals. Possible interactions and the role of measuring total antioxidant capacity is considered in some detail. In contrast to most nutrients, there is a marked lack of biomarkers of either exposure or effect for most non-nutrients. The role of biological effect monitoring is considered for dietary contaminants, fumonisins and polyhalogenated aromatic hydrocarbons. Aflatoxins are discussed to exemplify food contaminants for which the biomarker approach has been extensively studied. Finally some compounds which are deliberately added to foods and some which appear as processing contaminants are each considered briefly in relation to the requirement for a biomarker of exposure to be developed.

Selenium kinetics and changes in glutathione peroxidase activities in patients receiving long-term parenteral nutrition and effects of supplementation with selenite

Selenium (Se) is an essential trace element in humans. Patients receiving long-term parenteral nutrition (PN) are at risk for Se deficiency. We investigated changes in Se levels and glutathione peroxidase (GSH-Px) activity in serum and tissue (red blood cells, RBC) in addition to urinary excretion of Se in patients receiving long-term PN with and without Se supplementation. In patients without Se supplementation, both Se levels and GSH-Px activity in serum decreased with duration of PN. The serum Se levels were below the lower limits of the control values in 19 of 33 patients (58%) who received PN for less than 1 mo. Conversely, RBC GSH-Px activity remained at a sufficient level in 9 of 12 patients (75%) who received PN for 3-6 mo. The RBC Se levels in all of these patients were lower than the control levels. Urinary Se concentrations were significantly correlated with serum Se concentrations by linear regression analysis (r = 0.707, P < 0.05). In patients with Se supplementation, urinary Se concentrations increased exponentially with increases in serum Se levels. These findings indicate that a time lag precedes the decrease in levels of serum Se, RBC Se, serum GSH-Px, and RBC GSH-Px in patients without Se supplementation and the increase in excretion of urinary Se in patients with Se supplementation. The monitoring of not only serum Se levels but also RBC GSH-Px activity and urinary Se levels is required for optimal Se supplementation during long-term PN.

Decrease of blood cholesterol and stimulation of antioxidative response in cardiopathy patients treated with endovenous ozone therapy

Patients with cardiac infarction show a decrease in glutathione peroxidase and superoxide dismutase activities, which are beginners in the scavenger processes of lipid peroxide and superoxide radicals, respectively. In this study, we investigate the effects of endovenous ozone therapy on serum lipid pattern and on antioxidant defense system, such as te glutathione redox one, in the blood of patients with myocardial infarct. Twenty-two patients who had an infarction, between 3 months and 1 year before the study, were treated with ozone by autohemotherapy during 15 sessions. A statistically significant decrease in plasma total cholesterol and low density lipoprotein was observed. High biologically significant increases on erythrocyte glutathione peroxidase and glucose 6-phosphate dehydrogenase activities were found. There was no change in plasma lipid peroxidation level. It was concluded that endovenous ozone therapy in patients with myocardial infarction has a beneficial effect on blood lipid metabolism, provoking the activation of antioxidant protection system.

Radioimmunoassay of glutathione peroxidase in human serum

Glutathione peroxidase (GSHPx) was purified from human serum and used for immunization of rabbits. Antiserum bound up to 75% of added 125I-GSHPx after precipitation with a second antibody. Human serum, but not sera from eight animal species, inhibited the binding of labelled GSHPx, indicating that the antiserum did not react with GSHPx from these species. GSHPx could be measured in less than 10 microliters of human serum by radioimmunoassay. In sera with widely varying selenium concentrations (0.1-2.9 mumol/l) the amount of GSHPx protein (0.3-6.3 mg/l) was strongly correlated with GSHPx activity (r = 0.94) and it was also correlated with serum selenium concentrations (r = 0.64). This indicates that GSHPx protein may be a valuable biological marker of selenium status. In samples with serum selenium concentrations of 0.8-1.2 mumol/l, the concentration of GSHPx was 3.3 (0.4) mg/l (mean (S.D.)), or 0.04 (0.005) mumol/l. This corresponded to 0.16 (0.02) mumol/l of GSHPx selenium and 16% (2.8)% of total serum selenium. The data suggest that the method can be used to measure the proportion of serum selenium that is located in GSHPx. Following storage of serum at room temperature, both serum GSHPx protein and activity declined, but addition of glutathione protected both GSHPx protein and activity.

Automated continuous-flow colorimetric determination of glutathione peroxidase with dichloroindophenol

Automation of the glutathione peroxidase enzyme assay has been problematical. Although such methods have been reported, they do not give equivalent results to the standard manual assay, wherein glutathione oxidation is coupled to NADPH oxidation via glutathione reductase. We report here the development of a fully automated, continuous-flow, colorimetric method for glutathione peroxidase assays in which glutathione oxidation is monitored by its effect on the reaction of glutathione with the colorimetric reagent 2,6-dichloroindophenol. This method has a linear response to glutathione peroxidase over an 800-fold range of enzyme concentrations. Results of assays done by this method in erythrocyte and plasma samples correlate well with the standard manual coupled assay (r = 0.997 and 0.923, respectively), with no evidence of systematic errors. The assay works equally well with hydrogen peroxide or cumene hydroperoxide as substrate and shows the same selectivity toward glutathione S-transferases as the standard coupled assay. The within-day repeatability and the between-day reproducibility were estimated as 1.1 to 6.4% and 1.3 to 7.1% (relative standard deviation), respectively. This method is suitable for enzyme determinations in whole blood, erythrocytes, plasma, and serum from rats, rabbits, monkeys, and humans.

Abnormalities of blood selenium and glutathione peroxidase activity in patients with acquired immunodeficiency syndrome and aids-related complex

Severe protein-calorie malnutrition is common in patients with AIDS and could contribute to the progressive deterioration characteristic of that disease. Selenium deficiency could also have a negative impact on immune function and other organ functions vital for recovery from infectious diseases. Therefore, to assess any role for selenium in AIDS we determined plasma and erythrocyte selenium levels and glutathione peroxidase activity in 13 patients with AIDS compared to 8 patients with AIDS-related complex (ARC) and 14 healthy controls. Plasma selenium levels were significantly reduced in AIDS patients compared to controls (p less than .0001) and to ARC (p less than .02). Erythrocyte selenium levels in both AIDS and ARC were also reduced compared to controls (p less than .02), but not to each other. Glutathione peroxidase activity in AIDS was 28.9 +/- 1.4 U/g Hb vs 38.4 +/- 6.9 in ARC (p = NS) and 52.3 +/- 1.7 in controls (p less than .0001 vs AIDS; p less than .02 vs ARC). When all groups were combined, there were significant correlations between total lymphocyte count and both plasma selenium (r = .53; p less than .002) and erythrocyte glutathione peroxidase activity (r = .65; p less than .0001). In addition, strong correlations were noted between plasma selenium and serum albumin (r = .68; p less than .0001), plasma selenium and glutathione peroxidase (r = .77; p less than .0001), and glutathione peroxidase and hematocrit (r = .66; p less than .0001). In AIDS or ARC, no correlations between selenium with disease duration or weight loss were present. We conclude that, in comparison to normals, patients manifesting infection with human immunodeficiency virus have evidence of selenium deficiency as determined by diminished plasma and erythrocyte levels and glutathione peroxidase activity. These abnormalities are most marked in patients with AIDS, but are also present in patients with AIDS-related complex. Selenium deficiency has important implications for the progression and pathogenesis of clinical disease in AIDS.