Antioxidant enzymatic activities in human blood cells after an allergic reaction to pollen or house dust mite

Molecular and biochemical evaluation of oxidative effects of cord blood CD34+ MPs on hematopoietic cells

A graft source for allogeneic hematopoietic stem cell transplantation is umbilical cord blood, which contains umbilical cord blood mononuclear cells (MNCs and mesenchymal stem cells, both an excellent source of extracellular microparticles (MPs). MPs act as cell communication mediators, which are implicated in reactive oxygen species formation or detoxification depending on their origin. Oxidative stress plays a crucial role in both the development of cancer and its treatment by triggering apoptotic mechanisms, in which CD34+ cells are implicated. The aim of this work is to investigate the oxidative stress status and the apoptosis of HL-60 and mononuclear cells isolated from umbilical cord blood (UCB) following a 24- and 48-hour exposure to CD34 + microparticles (CD34 + MPs). The activity of superoxide dismutase, glutathione reductase, and glutathione S-transferase, as well as lipid peroxidation in the cells, were employed as oxidative stress markers. A 24- and 48-hour exposure of leukemic and mononuclear cells to CD34 + -MPs resulted in a statistically significant increase in the antioxidant activity and lipid peroxidation in both cells types. Moreover, CD34 + MPs affect the expression of BCL2 and FAS and related proteins and downregulate the hematopoietic differentiation program in both HL-60 and mononuclear cells. Our results indicate that MPs through activation of antioxidant enzymes in both homozygous and nonhomozygous cells might serve as a means for graft optimization and enhancement.

The Phase 3 INVIGORATE Trial of Reproxalap in Patients with Seasonal Allergic Conjunctivitis

Purpose

There is an unmet need for new treatments for allergic conjunctivitis.

Objective

To assess the activity of reproxalap, a novel reactive aldehyde species modulator, in a real-world model of seasonal allergen exposure.

Methods

The INVIGORATE Trial, a prospective, quadruple-masked, vehicle-controlled, crossover, sequence-randomized Phase 3 trial, tested the efficacy of reproxalap in adults with a history of moderate to severe allergic conjunctivitis, ragweed pollen allergy, and allergen chamber-induced ocular itching and redness. Patients were randomly assigned (1:1) to receive 0.25% reproxalap ophthalmic solution or vehicle, followed by a 2-week washout period before crossing over to the other test article. The primary endpoint was ocular itching from 110 to 210 minutes after chamber entry; the key secondary endpoint was ocular redness over the chamber duration (0-4 scales for both endpoints).

Results

Of the 95 randomly assigned patients, 89 completed all visits (reproxalap to vehicle: n = 46; vehicle to reproxalap: n = 43). Primary and key secondary endpoints were met: reproxalap significantly reduced ocular itching (mean [SE]: -0.50 [0.03], p < 0.001) and redness (-0.14 [0.01], p < 0.001) relative to vehicle. Responder analyses confirmed the clinical relevance of both end points. Reproxalap was safe and well tolerated. No clinically significant changes in safety assessments were observed. No serious or severe treatment-emergent adverse events (TEAEs) were reported. The most commonly reported TEAE was mild and transient installation site irritation after reproxalap versus vehicle administration.

Conclusion

In this well-controlled allergen chamber trial, reproxalap was statistically superior to vehicle across typical symptoms and signs of allergic conjunctivitis.

Trial Registration

NCT04207736.

Allergen Differences and Correlation Analysis in Siblings Diagnosed with Respiratory Allergic Diseases

INTRODUCTION

Many parents of children with allergies are worried whether their subsequent children will have allergic reactions to the same allergens. Much of the current research on sibling allergens has been focused on twins; however, in real life, very few children are twins. Our study provides an opportunity to initially explore the sensitivity to allergens in siblings diagnosed with respiratory allergic diseases.

METHODS

Siblings diagnosed with bronchial asthma and/or allergic rhinitis in the Outpatient Department of Allergy Department of Yantai Yuhuangding Hospital from January 2018 to December 2021 were selected. The siblings were divided into elder group and younger group. Data of gender, age, feeding history, serum total IgE (TIgE), absolute eosinophil counts, and allergen-specific IgE (sIgE) were collected and analyzed. The sIgEs of allergens were divided into six categories and analyzed.

RESULTS

A total of 98 sibling pairs of patients were included in this study. There were no differences in the positive rates of the different types of allergens, TIgE values, and the absolute eosinophil values between the elder and younger groups and between different genders. Logistic regression analysis indicated that the elder siblings allergic to dust mites, fungi, weed pollens, or food had a statistically significant increased risk of having their younger sibling sensitive to these types of allergens (all p <0.05), and the risk of allergy to dust mites, weed pollens, and tree pollens of younger group increased with age (all p <0.05). Except for the sIgE values of dust mites, the sIgE values of the other allergens were significantly correlated between the two groups (all p <0.05).

CONCLUSION

The positive rates of different allergens were similar between siblings. Elder siblings with dust mites, fungi, weed pollen, or food allergen positivity will have younger siblings sensitive to the same types of allergens.

Oxidation potential and coupling effects of the fractionated components in airborne fine particulate matter

Fine particulate matter (PM_2.5) can induce the generation of reactive oxygen species (ROS) and damage human tissues. Fully understanding the generation mechanism of oxidative toxicity of PM is challenging due to the extremely complex composition. Classification methods may be helpful in understanding the ROS production mechanisms of complex PM. This study used a solvent extraction and solid phase extraction methods to separate five different components from PM_2.5 includes non-extractable components that have rarely been studied before, and discussed the coupling effect and heterogeneous characteristics of oxidation activity they produced. It is found that the water-soluble component contribute about half of the PM oxidation activity, and metal ions probably contribute most of the oxidation activity. Experimental results show that oxygen molecules is the main precursor of ROS production, which depends on whether the aerosol component has catalytic conversion ability. After mixing humic-like substance (HULIS) and hydrophilic water-soluble (HP-WSM) PM, the oxidation activity increased, it is most likely to be a synergistic effect between HULIS and metal ions is dominant, but limited contribution to oxidation activity. It turns out that the non-extractable and water-insoluble components have higher oxidation activity than the water-soluble components, and the two components exhibited a more durable ability to produce ¹O₂. The reaction of soluble components to produce ROS is homogeneous, but it is obviously heterogeneous for these insoluble components. This study suggests that future attention should be paid to the oxidative toxicity of the non-extractable component, and that single PM component or compound cannot simply be studied independently.

Early Onset and Broad Activity of Reproxalap in a Randomized, Double-Masked, Vehicle-Controlled Phase 2b Trial in Dry Eye Disease

PURPOSE

To assess the activity of reproxalap, a novel reactive aldehyde species (RASP) inhibitor, relative to vehicle in patients with dry eye disease (DED) DESIGN: Randomized, double-masked, vehicle-controlled Phase 2b trial METHODS: Three hundred patients with DED were randomly assigned 1:1:1 at multiple US sites to receive 0.1% topical ocular reproxalap, 0.25% topical ocular reproxalap, or vehicle. Eyes were treated bilaterally 4 times daily for 12 weeks. Standard signs and symptoms of DED were assessed at baseline and at Weeks 2, 4, 8, and 12.

RESULTS

A dose response was observed for signs and symptoms of DED. Relative to vehicle over 12 weeks of therapy, the largest symptomatic improvement was observed in ocular dryness (0.25%, P = .047), and the largest objective sign improvement was observed in nasal region fluorescein staining (0.25%, P = .030). A greater proportion of patients receiving 0.25% reproxalap vs. vehicle reported dryness scores of 0 (P = .012). Improvements in combined DED symptoms were evident by the first post-baseline visit (Week 2, 0.25%, P < .0001) in patients with baseline scores greater than or equal to median values. No significant changes in safety measures were observed.

CONCLUSION

The novel RASP inhibitor reproxalap demonstrated rapid, broad, and clinically relevant symptomatic control, in conjunction with statistically significant improvement over vehicle in signs of DED as demonstrated by fluorescein staining, in DED patients over 12 weeks of therapy. The results represent the first vehicle-controlled evidence for the therapeutic potential of RASP inhibition to mitigate the signs and symptoms of dry eye disease.

A Randomized Double-Masked Phase 2a Trial to Evaluate Activity and Safety of Topical Ocular Reproxalap, a Novel RASP Inhibitor, in Dry Eye Disease

Purpose: To determine whether reproxalap, a novel reactive aldehyde species (RASP) inhibitor, is safe and effective for the treatment of the signs and symptoms of dry eye disease (DED).

Methods: In a randomized double-masked parallel-group Phase 2a trial of 3 topical ocular reproxalap formulations (0.1% ophthalmic solution, 0.5% ophthalmic solution, and 0.5% lipid ophthalmic solution), 51 patients with DED were randomly assigned 1:1:1 at a single US site. Eyes were treated bilaterally 4 times daily for 28 days, and standard DED signs and symptoms were assessed at baseline and after 7 and 28 days of dosing. Tear RASP levels were assessed at baseline and at day 28.

Results: The effect of treatment on DED signs and symptoms was similar across the treatment arms, and pooled data from the 28-day treatment period demonstrated significant improvement from baseline in Symptom Assessment in Dry Eye Disease score (P = 0.003), Ocular Discomfort Scale score (P < 0.0001), Ocular Discomfort Score and 4-Symptom Questionnaire overall score (P = 0.0004), Schirmer's test (P = 0.008), tear osmolarity (P = 0.003), and lissamine green total staining score (P = 0.002). Improvements in DED symptoms were evident within 1 week of therapy, and effect sizes generally approached or exceeded 0.5. No significant changes in safety measures were observed.

Conclusion: The results suggest that the novel RASP inhibitor reproxalap has the potential to mitigate the signs and symptoms of DED, and may represent a new, rapidly and broadly active treatment approach for DED (NCT03162783).

In vitro toxicity of dimethyl phthalate to human erythrocytes: From the aspects of antioxidant and immune functions

In the study, the effects of dimethyl phthalate (DMP) on the antioxidant defense capacity and immune functions of human erythrocytes were experimentally explored. DMP affected the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) and the contents of glutathione (GSH) and malondialdehyde (MDA) in erythrocytes, thus impairing the function of antioxidant defense system of erythrocytes. When DMP concentration increased from 0 to 28 μmol L^-1, the SOD and GPX activities were increased firstly and then gradually decreased. When DMP concentration was below 20 μmol L^-1, the relative activity of SOD was enhanced by DMP and the effect was known as hormesis. The relative activity of GPX was also increased when the concentration of DMP was below 12 μmol L^-1. The CAT activity was more significantly inhibited by DMP than the activities of SOD and GPX, whereas the relative GSH content was increased by DMP. MDA levels were significantly changed after the exposure to DMP (0-24 μmol L^-1). The experimental results of the activity of SOD and CAT, and the content of MDA also suggested that DMP could inhibit the immune functions of red blood cells (RBCs), which were further proved by the decrease of two indicators (RBC-C₃b and RBC-IC) due to the destruction of C₃b receptor with immune adherence function on erythrocyte membrane. The study provides a deep understanding of the toxicity of DMP on erythrocytes.

Heat-induced protein oxidation of soybean meal impairs growth performance and antioxidant status of broilers

This study aimed to evaluate the impact of oxidative modification on soybean meal (SBM) proteins after exposure to different heating times, and the effects of the oxidized SBM on the growth performance [average daily feed intake (ADFI), average daily gain (ADG), and feed to gain ratio (F: G)], oxidative redox status [(reactive oxygen species (ROS), total antioxidant capacity (TAC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), and protein carbonyl (PC)]. A total of 400 one-day-old Arbor Acres chicks were randomly divided into 5 treatment groups with 8 replicates of 10 birds each. Birds in the control group (CON) were fed diet containing non-heated SBM, and those in the treatment groups were fed SBM heated at 100°C for 1, 2, 4, and 8 h, for 42 d. Heated SBM (HSBM) showed a relatively higher PC content in vitro. The ADG decreased, whereas the F:G increased linearly with an increase in heating time during the starter (days 1 to 21), grower (days 22 to 42), and the overall growth phases (days 1 to 42; P < 0.05). However, the ADFI decreased linearly only during the grower phase (P < 0.05). The plasma, liver, and jejunum ROS levels, MDA concentrations, and PC contents increased linearly (P < 0.05) in broilers fed HSBM. Furthermore, the TAC in the plasma and jejunum, and the total SOD and GSH-Px activities in the plasma, liver, and jejunum decreased linearly (P < 0.05) in broilers when feeding HSBM. (P < 0.05). The mRNA level of Nrf2 in the liver and jejunum was lower (P < 0.05) in broilers fed diet containing the SBM after 8 h heat-treatment than in those fed the CON diet at days 42. This study suggested that heat-induced protein oxidation of SBM could decrease growth performance and impair antioxidant status of broilers.

Interaction Between Catalase Gene Promoter Polymorphisms and Indoor Environmental Exposure in Childhood Allergic Rhinitis

BACKGROUND

Allergic rhinitis (AR) is a highly prevalent chronic inflammatory disease affecting nearly 40% of the children in Taiwan. Genetic susceptibility may interact with specific environmental factors leading to allergic disease development.

METHODS

To assess the interactions between catalase gene promoter polymorphisms and environmental factors on the risk of AR, we conducted a case-control study in Taiwan. Data on AR and environmental factors were collected from 800 children using the ISSAC questionnaire. The case group consisted of 263 children with AR, and the control group consisted of =537 healthy children. Genotyping was performed for rs1001179 and rs769214 polymorphisms, and environmental exposure was assessed using four indicators including dwelling visible molds, mold odor, moisture on surfaces, and water damage.

RESULTS

We found that the presence of visible molds, mold odor, and moisture was associated with AR. An apparent joint effect of the GG genotype and mold odor, compared with the AA and AG combined genotypes and without any exposure indicator (adjusted odds ratio [OR] = 1.95 [95% confidence interval (CI) = 1.20, 3.18]; interaction adjusted odds ratio = 2.59 [95% CI = 1.27, 5.30]), was observed.

CONCLUSIONS

Our findings suggest that gene-environment interactions between the catalase polymorphism rs769214 and mold odor may play an important role in childhood AR development.

Importance of internal mammary artery perfusion in cardiac ischemia and reperfusion

Purpose: Our purpose was to investigate the changes in antioxidant defense systems due to internal mammary artery (IMA) perfusion during coronary artery bypass graft (CABG) operations in which proximal anastomoses were completed under partial bypass with the aid of a side-biting clamp.

Material and Method: Twenty-five patients to be studied were divided into two groups according to the criterion of whether during proximal anastomoses left internal mammary artery (LIMA) perfusion was applied ( n = 15, LIMA group) or not ( n = 10, non-LIMA group). The erythrocyte catalase (CAT), superoxide dismutase (SOD), serum lipid peroxidation (LPO) products and whole blood reduced glutathione (GSH) levels were measured in the blood samples taken from the coronary sinus before cardiopulmonary bypass (CPB) (t1), before declamping (t2), at the 5th min after declamping (t3), at the 5th (t4) and 15th (t5) min after removing the side-biting clamp.

Results: While erythrocyte CAT enzyme activity decreases in both groups after the basal measurements, no significant difference was detected between the groups. Although the GSH levels did not differ at t1, t2 and t3, they were found to be higher in the LIMA group at t4 ( p = 0.006) and t5 ( p = 0.021). The erythrocyte SOD enzyme activity decreased after the basal measurements in both groups, but this reduction was less in the LIMA group at t4 ( p= 0.034) and t5 ( p = 0.018) compared to the other group. LPO products rose in both groups when reperfusion started after declamping. The levels of LPO products were significantly higher at t4 and t5 in the non-LIMA group than the other group ( p = 0.011 and p = 0.008).

Conclusion: If proximal anastomoses of coronary grafts are completed under partial bypass, permitting LIMA perfusion during this procedure will be beneficial to antioxidant defense systems.

Oxidative stress and damage to erythrocytes in patients with chronic obstructive pulmonary disease--changes in ATPase and acetylcholinesterase activity

The study indicates, for the first time, the changes in both ATPase and AChE activities in the membrane of red blood cells of patients diagnosed with COPD. Chronic obstructive pulmonary disease (COPD) is one of the most common and severe lung disorders. We examined the impact of COPD on redox balance and properties of the membrane of red blood cells. The study involved 30 patients with COPD and 18 healthy subjects. An increase in lipid peroxidation products and a decrease in the content of -SH groups in the membrane of red blood cells in patients with COPD were observed. Moreover, an increase in the activity of glutathione peroxidase and a decrease in superoxide dismutase, but not in catalase activity, were found as well. Significant changes in activities of erythrocyte membrane enzymes in COPD patients were also evident demonstrated by a considerably lowered ATPase activity and elevated AChE activity. Changes in the structure and function of red blood cells observed in COPD patients, together with changes in the activity of the key membrane enzymes (ATPases and AChE), can result from the imbalance of redox status of these cells due to extensive oxidative stress induced by COPD disease.

Correlation between bone mineral density and oxidative stress in postmenopausal women

BACKGROUND

Postmenopausal osteoporosis affects large fraction of elderly women. Oxidative stress (OS) appears to be involved in its pathogenesis. The scarcity of human studies focusing on the correlation between bone mineral density (BMD) and OS in postmenopausal women has prompted us to study on this issue.

MATERIALS AND METHODS

We conducted a cross sectional study in 95 subjects, between 21-65 years of age, including postmenopausal osteoporotic females (n = 35), healthy postmenopausal females (n = 30) and healthy females in reproductive age group (n = 30). We measured serum antioxidant activity of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and total antioxidant power (TAP). BMD was obtained at lumbar spine and femur neck by dual-energy X-ray absorptiometry scan. Osteoporosis was considered when subjects had a BMD of 2.5 standard deviations or more below the mean value for young adults.

RESULTS

Serum GPx, SOD, catalase and TAP level were found significantly lower in osteoporotic postmenopausal group as compared to healthy postmenopausal women and women in healthy reproductive age group healthy reproductive women (P < 0.005). but correlation between BMD and serum antioxidants were not found to be statistically significant (P > 0.005).

CONCLUSION

These findings support that oxidative stress plays an important role in pathogenesis of postmenopausal osteoporosis. We did not find any significant association between BMD and serum level of antioxidants (P > 0.05). The failure to detect this association does not preclude the role of OS in osteoporosis because OS is complex and dynamic process.

Manganese superoxide dismutase and oxidative stress modulation

Oxidative stress is characterized by imbalanced reactive oxygen species (ROS) production and antioxidant defenses. Two main antioxidant systems exist. The nonenzymatic system relies on molecules to directly quench ROS and the enzymatic system is composed of specific enzymes that detoxify ROS. Among the latter, the superoxide dismutase (SOD) family is important in oxidative stress modulation. Of these, manganese-dependent SOD (MnSOD) plays a major role due to its mitochondrial location, i.e., the main site of superoxide (O(2)(·-)) production. As such, extensive research has focused on its capacity to modulate oxidative stress. Early data demonstrated the relevance of MnSOD as an O(2)(·-) scavenger. More recent research has, however, identified a prominent role for MnSOD in carcinogenesis. In addition, SOD downregulation appears associated with health risk in heart and brain. A single nucleotide polymorphism which alters the mitochondria signaling sequence for the cytosolic MnSOD form has been identified. Transport into the mitochondria was differentially affected by allelic presence and a new chapter in MnSOD research thus begun. As a result, an ever-increasing number of diseases appear associated with this allelic variation including metabolic and cardiovascular disease. Although diet and exercise upregulate MnSOD, the relationship between environmental and genetic factors remains unclear.

Airway wall thickness of allergic asthma caused by weed pollen or house dust mite assessed by computed tomography

PURPOSE

Little was known about Airway wall thickness of asthma patients with different allergen allergy. So we explored the possible difference of Airway wall thickness of asthma patients mono-sensitized to weed pollen or HDM using high-resolution computed tomography.

MATERIALS AND METHODS

85 severe asthma patients were divided into weed pollen group and HDM group according to relevant allergen. 20 healthy donors served as controls. Airway wall area, percentage wall area and luminal area at the trunk of the apical bronchus of the right upper lobe were quantified using HRCT and compared. The values of pulmonary function were assessed as well.

RESULTS

There were differences between HDM group and weed pollen group in WA/BSA,WA% and FEF25-75% pred, and no significant difference in FEV1%pred, FEV1/FVC and LA/BSA. In weed pollen group, WA/BSA was observed to correlate with the duration of rhinitis, whereas in HDM group, WA/BSA and LA/BSA was observed to correlate with the duration of asthma. In weed pollen group, FEV1/FVC showed a weak but significant negative correlation with WA%, but in HDM group FEV1/FVC showed a significant positive correlation with WA% and a statistical negative correlation with LA/BSA. FEV1/FVC and FEF25-75% pred were higher and WA/BSA and LA/BSA were lower in healthy control group than asthma group. FEV1%pred and WA% was no significant difference between asthma patients and healthy subjects.

CONCLUSION

There are differences between HDM mono-sensitized subjects and weed pollen mono-sensitized subjects, not only in airway wall thickness, but also small airway obstruction.

Probing the in vitro cytotoxicity of the veterinary drug oxytetracycline

The study investigated the effect of oxytetracycline (OTC) on the anti-oxidative defense system, the structure (hemolysis rate and morphology) and function (ATP enzyme activity) of human red blood cells (hRBCs) to investigate the possible toxic mechanism of OTC to hRBCs. The experimental results indicate that OTC can cause a decline in the function of the antioxidant defense system of hRBCs, resulting in oxidative stress. OTC can bring about morphological changes to hRBCs, and further leads to hemolysis, when the concentration of OTC is over 8×10(-5) M (about 164 µg/ml). At a low OTC concentration, below 4×10(-5) M (82 µg/ml), OTC can enhance the activity of ATP enzyme of hRBCs, known as hormesis. However, at a high concentration, above 4×10(-5) M (about 82 µg/ml), the ATP enzymatic activity was inhibited, affecting the function of hRBCs. The estalished mechanism of toxicity of OTC to hRBCs can facilitate a deeper understanding of the toxicity of OTC in vivo.

Protective effects of stem bark of Harungana madgascariensis on the red blood cell membrane

Background

Anemia is a condition that has multiple origins. One such origin is the destruction of red blood cells’ (RBCs) membrane induced by free radicals. Treatment of anemia could therefore be enhanced by the use of free radicals’ scavengers potentially found in some medicinal plants. In this study, the protective effect of Harungana madagascariensis on the RBCs’ membrane physiology was investigated in vitro and in vivo.

Methods

In vitro hemolytic anemia was induced by incubation of fresh human RBCs with carbontetrachloride (CCl₄) in Olive oil (Oo). Relaxation times of protons excited at 20 MHz (Carr-Purcell-Meiboom-Gill pulse sequence) in the absence or presence of paramagnetic Mn²⁺ ions (T_2i for “extracellular” water and T_2a for “intracellular” water, respectively) were determined at several temperatures (25–37°C) via Nuclear Magnetic Resonance (NMR) on a Bruker Minispec spectrometer. Water exchange times (T_e) were consequently calculated using the Conlon-Outhred equation: 1/T_e = (1/T_2a) – (1/T_2i). Morphological characteristics (mean cell volume, V, and cell surface area, A) were determined by photonic microscopy and the RBCs’ diffusional water permeability (P_d) was calculated as P_d = (1/T_e)*(V_a/A), where V_a is the aqueous volume in the RBC and is about 0.7 of the cell volume (V). The activation energy of the diffusional process (E_a) for the respective temperature range was estimated using the Arrhenius modified equation k = A(T/T₀)ⁿ*e^-Ea/RT. Inhibition of the water diffusion induced by incubation with para-chloro-mercuribenzoic acid (PCMB) at 25, 30 and 37°C was calculated as I(%) = [(Pd control – Pd sample)/Pd control]*100.

To investigate the protective influence of the extract on the RBC membrane, inhibition of the water permeability was evaluated on membranes pre-incubated with the Harungana madagascariensis extract. Male rats were used in in vivo investigations. Malondialdehyde (MDA) and cholesterol in the RBC membrane were estimated by induction of lipid peroxidation while the antioxidant properties of catalase (CAT) and superoxide dismutase (SOD) on the membrane were evaluated in regard to their antioxidant properties on the membrane.

Results

T_2a significantly decreased at each temperature. Te results were higher in both RBCs and RBCs + extract groups incubated with PCMB compared to non-incubated controls, but differences were not statistically significant. A high percentage (73.81 ± 7.22) of RBCs pre-incubated with the extract presented the regular biconcave shape. Inhibition by PCMB of the RBCs’ membrane water permeability was increased at 30°C and decreased in the presence of extract (25°C and 37°C), while Ea decreased from 30.52 ± 1.3 KJ/mol to 25.49 ± 1.84 KJ/mol. Presence of the Harungana madagascariensis extract normalized the SOD and CAT activities as well as the MDA and membrane cholesterol concentrations altered by the CCl₄-induced oxidative stress.

Conclusion

Harungana madagascariensis could protect the RBCs’ membrane through its antioxidative properties.

Determination of immunological stress and oxygen free radical formation in white blood cells during allergen immunotherapy

Background

Airway inflammation represents the basis of respiratory allergic disease and is generally associated with increased oxidative stress. As a consequence of successful treatment leading to hyposenzibilization and remission of symptoms, decrease of reactive oxygen formation is expected.

Material/Methods

This preliminary study evaluates the production of oxygen free radicals in white blood cells and changes in basic immunological parameters in a cohort of 50 patients (27 females and 23 males, age 14–48 years) with upper airway allergic inflammation caused by pollens, before and during specific immunotherapy.

Results

We found an unexpected significant increase in the free radical concentration during and after treatment in comparison to values before the treatment and to the control group. Statistical analysis also found significant increase of IgG3 after initial treatment and also 1 year after allergen immunotherapy. Although there were similar trends in the elevated ROS and elevated IgG3, these were not statistically significant.

Conclusions

We observed changes in oxidative mechanisms in white blood cells of patients treated with AIT. Allergen immunotherapy works at a multilayer level and influences airway inflammation as well as the protective antimicrobial defense in treated patients. Further studies for understanding the mechanisms involved in oxidative stress as well as for laboratory monitoring of therapeutic approaches in allergic diseases are needed.

Comparative in vivo antioxidant capacity of DL-2-hydroxy-4-methylthiobutanoic acid (HMTBA) and DL-methionine in male mice fed a high-fat diet

BACKGROUND

In animal diets, methionine (Met) is considered to be the first limiting amino acid, and the activity of synthetic Met is typically added either as DL-methionine (DLM) or as DL-2-hydroxy-4-methylthiobutanoic acid (HMTBA). It has been demonstrated that HMTBA exhibits a higher antioxidant capability in vitro as compared to DLM. However, the difference in antioxidant capability between DLM and HMTBA in vivo is unknown.

METHODS

In the present study, 60 male C57BL/6 mice were randomly divided into six groups and fed either a normal diet (NFD, 5.37% fat) or a high-fat diet (HFD, 19.7% fat) in conjunction with 0.2% DLM, 0.2% HMTBA or 0.1% DLM and 0.1% HMTBA for 4 weeks.

RESULTS

HFD supplemented with 2% DLM and NFD with 2% HMTBA both induced adverse affects in relation to serum lipid parameters and depressed antioxidant defense systems in the digestive system. However, these changes were restored in the 0.2% HMTBA-treated HFD group. Furthermore, no significant differences were found in the lipid parameters and antioxidant status in the NFD and HFD group supplemented with 0.1% DLM and 0.1% HMTBA.

CONCLUSION

HMTBA restored oxidative redox status under OS conditions and its antioxidant properties were positively correlated with the dosage included in diet.

Green tea extract (epigallocatechin-3-gallate) reduces efficacy of radiotherapy on prostate cancer cells

OBJECTIVES

To assess the influence of epigallocatechin-3-gallate (EGCG) on the efficacy of ionizing radiation on prostate cancer cells because of the increased use of dietary interventions, especially by patients with prostate cancer. Radiotherapy is used to treat localized prostate cancer. Some people consume green tea (EGCG) as a chemopreventive agent against prostate cancer. Green tea can act as an antioxidant and induce superoxide dismutase enzymes, which could scavenge the free oxygen radicals generated by radiotherapy.

METHODS

Prostate cancer cell line DU145 cells were treated with EGCG or radiotherapy, or both. Cell death was assessed using trypan blue cell counting, and apoptosis was confirmed by assessing poly (adenosine phosphate ribose) polymerase cleavage. The antioxidant potential was assessed using Western immunoblotting for manganese superoxide dismutase and copper zinc superoxide dismutase enzymes. Radiotherapy was delivered using a linear accelerator. Cell cycle analysis was performed using flow cytometry.

RESULTS

Radiotherapy at 3.5 Gy induced a 5.9-fold increase in apoptosis of DU145 cells. Subapoptotic doses of EGCG (1.5-7.5 μM) significantly reduced ionizing radiation-induced apoptosis (P < .001), with the inhibitory effect of EGCG on ionizing radiation being most effective when added 30 minutes before radiotherapy (P < .001). In addition, when radiotherapy and EGCG were used together, an approximate 1.5-fold increase in manganese superoxide dismutase levels was seen compared with the control and a 2-fold increase compared with radiotherapy alone.

CONCLUSIONS

Radiotherapy is effective in inducing apoptosis in DU145 cells, but its effect was significantly reduced in the presence of EGCG, and this was associated with an increase in the induction of manganese superoxide dismutase.

Antioxidant status and immune activity of glycyrrhizin in allergic rhinitis mice

Oxidative stress is considered as a major risk factor that contributes to increased lipid peroxidation and declined antioxidants in some degenerative diseases. Glycyrrhizin is widely used to cure allergic diseases due to its medicinal properties. In the present study, we evaluated the role of glycyrrhizin on lipid peroxidation and antioxidant status in the blood and nasal mucosa of allergic rhinitis (AR) mice. Mice were divided into six groups: normal control mice, model control (MC) mice, three glycyrrhizin-treated mice groups and lycopene-treated mice. Sensitization-associated increase in lipid peroxidation was observed in the blood and nasal mucosa of MC mice. Activities of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), total antioxidant capacity (TAOC) and levels of glutathione (GSH) were found to be significantly decreased in the blood and nasal mucosa in MC mice when compared to normal control mice. However, normalized lipid peroxidation and antioxidant defenses were reported in the glycyrrhizin-treated and lycopene-treated mice. Moreover, glycyrrhizin treatment still enhanced IFN-γ and reduced IL-4 levels in glycyrrhizin-treated mice. These findings demonstrated that glycyrrhizin treatment enhanced the antioxidant status and decreased the incidence of free radical-induced lipid peroxidation and improved immunity activities in the blood and nasal mucosa of AR mice.

Imaging in real-time with FRET the redox response of tumorigenic cells to glutathione perturbations in a microscale flow

Despite the potential benefits of selective redox-modulating strategies for cancer therapy, an efficacious methodology for testing therapies remains elusive because of the difficulty in measuring intracellular redox potentials over time. In this report, we have incorporated a new FRET-based biosensor to follow in real time redox-sensitive processes in cells transformed to be tumorigenic and cultured in a microfluidic channel. A microfluidic network was used to control micro-scale flow near the cells and at the same time deliver drugs exogenously. Subsequently, the response of a redox homeostasis circuit was tested, namely reduced glutathione (GSH)/oxidized glutathione(GSSG), to diamide, a thiol oxidant, and two drugs used for cancer therapies: BSO (L-buthionine-[SR]-sulfoximine) and BCNU (carmustine). The main outcome from these experiments is a comparison of the temporal depletion and recovery of GSH in single living cells in real-time. These data demonstrate that mammalian cells are capable of restoring a reduced intracellular redox environment in minutes after an acute oxidative insult is removed. This recovery is significantly delayed by (i) the inhibition of GSH biosynthesis by BSO; (ii) the inactivation of glutathione reductase by BCNU; and (iii) in tumorigenic cells relative to an isogenic non-tumorigenic control cell line.

Transcriptomic analysis of the temporal host response to skin infestation with the ectoparasitic mite Psoroptes ovis

Background

Infestation of ovine skin with the ectoparasitic mite Psoroptes ovis results in a rapid cutaneous immune response, leading to the crusted skin lesions characteristic of sheep scab. Little is known regarding the mechanisms by which such a profound inflammatory response is instigated and to identify novel vaccine and drug targets a better understanding of the host-parasite relationship is essential. The main objective of this study was to perform a combined network and pathway analysis of the in vivo skin response to infestation with P. ovis to gain a clearer understanding of the mechanisms and signalling pathways involved.

Results

Infestation with P. ovis resulted in differential expression of 1,552 genes over a 24 hour time course. Clustering by peak gene expression enabled classification of genes into temporally related groupings. Network and pathway analysis of clusters identified key signalling pathways involved in the host response to infestation. The analysis implicated a number of genes with roles in allergy and inflammation, including pro-inflammatory cytokines (IL1A, IL1B, IL6, IL8 and TNF) and factors involved in immune cell activation and recruitment (SELE, SELL, SELP, ICAM1, CSF2, CSF3, CCL2 and CXCL2). The analysis also highlighted the influence of the transcription factors NF-kB and AP-1 in the early pro-inflammatory response, and demonstrated a bias towards a Th2 type immune response.

Conclusions

This study has provided novel insights into the signalling mechanisms leading to the development of a pro-inflammatory response in sheep scab, whilst providing crucial information regarding the nature of mite factors that may trigger this response. It has enabled the elucidation of the temporal patterns by which the immune system is regulated following exposure to P. ovis, providing novel insights into the mechanisms underlying lesion development. This study has improved our existing knowledge of the host response to P. ovis, including the identification of key parallels between sheep scab and other inflammatory skin disorders and the identification of potential targets for disease control.

Development of a functional cis-prolyl bond biomimetic and mechanistic implications for nickel superoxide dismutase

During recent years several peptide-based Ni superoxide dismutase (NiSOD) models have been developed. These NiSOD models show an important structural difference compared to the native NiSOD enzyme, which could cause a completely different mechanism of superoxide dismutation. In the native enzyme the peptide bond between Leu4 and Pro5 is cis-configured, while the NiSOD models exhibit a trans-configured peptide bond between these two residues. To shed light on how the configuration of this single peptide bond influences the activity of the NiSOD model peptides, a new cis-prolyl bond surrogate was developed. As surrogate we chose a leucine/alanine-based disubstituted 1,2,3-triazole, which was incorporated into the NiSOD model peptide replacing residues Leu4 and Pro5. The yielded 1,5-disubstituted triazole nickel peptide exhibited high SOD activity, which was approximately the same activity as its parent trans-configured analogue. Hence, the conformation of the prolyl peptide bond apparently has of minor importance for the catalytic activity of the metallopeptides as postulated in literature. Furthermore, it is shown that the triazole metallopeptide is forming a stable cyanide adduct as a substrate analogue model complex.

Influence of desloratadine on selected oxidative stress markers in patients between 3 and 10 years of age with allergic perennial rhinitis

The objective of this study was to evaluate the selected oxidative stress parameters in 50 (35 males, 15 females) pediatric patients aged from 3 to 10 years diagnosed with perennial allergic rhinitis before and after the two-month treatment with desloratadine at the dose of 5 mg/day and in 11 healthy individuals. Oxidative stress was determined by the analysis of the reactive oxygen species neutralizing enzyme activity in erythrocytes superoxide dismutase and catalase, the estimation of free radical processes intensity: content of malondialdehyde in erythrocytes and the level of plasma hydroperoxides as well as by quantification of the plasma total antioxidant status. Changes in the studied parameters in untreated perennial allergic rhinitis patients indicate increased oxidative stress. The treatment with desloratadine normalized the superoxide dismutase and catalase activity as well as the malondialdehyde formation. The plasma hydroperoxides level in treated patients with perennial allergic rhinitis is reduced as compared with untreated subjects, although still higher than in the control. Desloratadine caused an increase in the total antioxidant status level, but it was not statistically significant. It can be concluded that oxidative stress is implicated in the pathogenesis of perennial allergic rhinitis. The results demonstrate that desloratadine exerts antioxidant effects in vivo.

New insight into the mode of action of nickel superoxide dismutase by investigating metallopeptide substrate models

For the first time, the existence of a substrate adduct of a nickel superoxide dismutase (NiSOD) model, based on the first nine residues from the N terminus of the active form of Streptomyces coelicolor NiSOD, has been proven and the adduct has been isolated. This adduct is based on the cyanide anion (CN(-)), as a substrate analogue of the superoxide anion (O(2)(*-)), and the nickel metallopeptide H-HCDLPCGVY-NH(2)-Ni. Spectroscopic studies, including IR, UV/Vis, and liquid- and solid-state NMR spectroscopy, show a single nickel-bound cyanide anion, which is embedded in the metallopeptide structure. This complex sheds new light on the question of whether the mode of action of the NiSOD enzyme is an inner- or outer-sphere mechanism. Whereas discussion was previously biased in favor of an outer-sphere electron-transfer mechanism due to the fact that binding of cyanide or azide moieties to the nickel active site had never been observed, our results are a clear indication in favor of the inner-sphere electron-transfer mechanism for the disproportionation of the O(2)(*-) ion, whereby the substrate is attached to the Ni atom in the active site of the NiSOD.

Normal delivery induced stress alters glutathione peroxidase and TNF-α in elderly primigravidas mononuclear cells

To probe the glutathione peroxidase (GPx) activity coupled to ROS and TNF-α levels in younger versus elderly primigravidas. Monocytes were isolated from blood of young and elderly primigravidas after 12 hrs, 24 hrs and 14 days postpartum. Age-matched healthy female donors served as controls. Thereafter, the above monocytes were subjected to evaluation of GPx activity, levels of pro-inflammatory cytokine TNF-α and reactivity/specificity towards anti-TNF-α antibody. Suppression in GPx activity with simultaneous enhancement of TNF-α levels in monocytes was observed after 12 hrs and 24 hrs of spontaneous labor pain-induced maternal delivery through normal vaginal route. Conversely, an enhancement of GPx activity and decrease in TNF-α levels were observed on day 14 of postpartum, thereby indicating reversal of the impaired neutralizing mechanisms. The antioxidant network combating ROS was stronger in younger primigravidas. Capability of TNF-α and ROS suppression was somewhat lesser in elderly primigravidas even 14 days of postpartum via normal vaginal route. The capability of GPx activity enhancement with simultaneous suppression in ROS and TNF-α, decreases in elderly primigravidas. This may act as one of the important parameters leading to a variety of complications encountered by elderly primigravidas.

Antioxidant status and superoxide anion radical generation in acute myeloid leukemia

OBJECTIVES

This study was undertaken to investigate if there is a disparity in the antioxidant status and the ability of superoxide anion (O(2)(-)) generation in the patients with acute myeloid leukemia (AML).

DESIGN AND METHODS

The peripheral blood samples from thirty AML patients and thirty-six healthy subjects were collected and leukocytes, erythrocytes and plasma were separated for use in various parameter measurements.

RESULTS

The generation of O(2)(-), as reflected by lucigenin-based CL (LBCL), by the leukocytes of patients with AML was found to be significantly elevated either in resting or stimuli-elicited condition as compared with that of healthy controls (p<0.05). Coincidentally, these data were matched up with the suppressed SOD activities, notably in Cu/Zn SOD isoform found in AML patients (p<0.05). Conversely, SOD and GPx activities in erythrocytes of patients with AML were shown to be significantly higher than their normal counterparts (p<0.05).

CONCLUSIONS

These data suggest that altered expression of antioxidant enzymes and higher capability of O(2)(-) generation by leukocytes seem to be a distinct feature of AML.

Protective effect of silymarin on erythrocyte haemolysate against benzo(a)pyrene and exogenous reactive oxygen species (H2O2) induced oxidative stress

The present study was carried out to evaluate the in vitro antioxidant properties and protective effects of silymarin (milk thistle) in human erythrocyte haemolysates against benzo(a)pyrene [B(a)P], a potent carcinogenic chemical. Protective effect of silymarin was assessed in vitro by monitoring the antioxidant enzymes and malondialdehyde in three groups of haemolysates-(I) vehicle control (II) B(a)P incubated group and (III) B(a)P co incubated with silymarin. The effects of silymarin on lipid peroxidation (LPO) and antioxidant enzymes [superoxide dismutase; SOD, catalase; CAT, glutathione peroxidase; GPx, glutathione reductase; GR and glutathione-S-transferases; GST] were assessed on haemolysates. It was observed that specific activity of antioxidant enzymes were significantly decreased and the malondialdehyde levels were elevated when haemolysates were incubated with B(a)P. The protective effect of silymarin is elucidated by the significant reversal of the antioxidant enzymes and reduction in the levels of malondialdehyde. In addition, haemolysates were incubated with B(a)P for 45 min and the B(a)P metabolite, 3-hydroxy benzo(a)pyrene (3-OH-B(a)P) was detected using HPLC. An increased level of the metabolite was detected in group II. Whereas, when haemolysates were co-incubated with silymarin, the reactive metabolite 3-OH-B(a)P was not detectable which further confirms the protective role of silymarin. Generation of 3-OH-B(a)P in group II implicates the possibility of reactive oxygen species (O2- and H2O2) production in haemolysates during cytochrome P4501A1 (CYP1A1) mediated Phase-I-metabolism. Hence, we incubated the haemolysates with exogenous reactive oxygen species H2O2 and assessed the protective role of silymarin against H2O2. From the results of our study, it was suggested that silymarin possess substantial protective effect and free radical scavenging mechanism against environmental contaminants induced oxidative stress damages.

Silymarin Protection against Major Reactive Oxygen Species Released by Environmental Toxins: Exogenous H2O2Exposure in Erythrocytes

Silymarin is a polyphenolic plant flavonoid (a mixture of flavonoid isomers such as silibinin, isosilibinin, silidianin and silichristin) derived from Silymarin marianum that has anti-inflammatory, hepatoprotective and anticarcinogenic effects. Our earlier studies have shown that silymarin plays a protective role against the oxidative damage induced by environmental contaminants like benzo(a)pyrene in erythrocyte haemolysates. During the detoxification of these environmental contaminants, the major reactive oxygen species generated is hydrogen peroxide (H(2)O(2)). Because H(2)O(2 )can easily penetrate into the cell and cause damage to biomolecules, the protective role of silymarin was further assessed against this cytotoxic agent in vitro in erythrocyte haemolysates. The protective effect was monitored by assessing the levels of the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-s-transferase, glutathione peroxidase and malondialdehyde (LPO) in three groups: vehicle control, H(2)O(2)-exposed groups and drug co-incubation group (H(2)O(2) + silymarin). The protective effect of silymarin on the non-enzymic antioxidant glutathione and haemolysis, methaemoglobin content and protein carbonyl content were also assessed. It was observed that the activities of antioxidant enzymes and glutathione were reduced and the malondialdehyde levels were elevated after H(2)O(2 )exposure. There were also alterations in haemolysis, methaemoglobin content and protein carbonyl content, whereas after the administration of silymarin, the antioxidant enzyme activities reversed to near normal with reduced malondialdehyde content and normalized haemolysis, methaemoglobin content and protein carbonyl content. The results suggest that silymarin possesses substantial protective effect and free radical scavenging mechanism against exogenous H(2)O(2)-induced oxidative stress damages, hence, can be used as a protective drug against toxicity induced by environmental contaminants.

Anti-oxidant enzyme activities and expression and oxidative damage in patients with non-immediate reactions to drugs

Adverse drug reactions with an immunological basis (ADRIB) may involve activation of other concomitant, non-specific mechanisms, amplifying the specific response and contributing to the severity and duration. One concomitant mechanism could be the generation of reactive oxygen species (ROS) and/or their detoxification by anti-oxidants, including anti-oxidant enzymes. We analysed the activity of the anti-oxidant enzymes Cu/Zn-superoxide dismutase (SOD), catalase (CAT) and cellular glutathione peroxidase (GPX), as well as certain markers of oxidative damage (thiobarbituric acid reactive substances (TBARS) and carbonyl content) in peripheral blood mononuclear cells from patients with non-immediate ADRIB using spectrophotometric methods and the anti-oxidant enzymes expression by quantitative real-time reverse transcription-polymerase chain reaction. SOD activity and expression were increased in all types of non-immediate reactions (urticaria, maculopapular exanthema and toxic epidermal necrolysis). Regarding oxidative damage, TBARS were increased in urticaria and maculopapular exanthema, and carbonyl groups in all types of reactions. Our observations indicate that oxidative damage occurs in non-immediate reactions. Carbonyl stress and the inadequacy of the anti-oxidant defences are probable causes.

Proteomic analysis of iron overload in human hepatoma cells

Iron-mediated organ damage is common in patients with iron overload diseases, namely, hereditary hemochromatosis. Massive iron deposition in parenchymal organs, particularly in the liver, causes organ dysfunction, fibrosis, cirrhosis, and also hepatocellular carcinoma. To obtain deeper insight into the poorly understood and complex cellular response to iron overload and consequent oxidative stress, we studied iron overload in liver-derived HepG2 cells. Human hepatoma HepG2 cells were exposed to a high concentration of iron for 3 days, and protein expression changes initiated by the iron overload were studied by two-dimensional electrophoresis and mass spectrometry. From a total of 1,060 spots observed, 21 spots were differentially expressed by iron overload. We identified 19 of them; 11 identified proteins were upregulated, whereas 8 identified proteins showed a decline in response to iron overload. The differentially expressed proteins are involved in iron storage, stress response and protection against oxidative stress, protein folding, energy metabolism, gene expression, cell cycle regulation, and other processes. Many of these molecules have not been previously suggested to be involved in the response to iron overload and the consequent oxidative stress.

An evaluation of cytosolic erythrocyte carbonic anhydrase and catalase in carcinoma patients: an elevation of carbonic anhydrase activity

OBJECTIVES

The antioxidant enzyme catalase and the CO2/HCO3- exchange enzyme carbonic anhydrase are both present in significant amounts in the cytosol of erythrocytes. The aim of the present study was to investigate whether these erythrocyte enzyme activities are altered in patients who have carcinoma.

DESIGN AND METHODS

Cytosolic erythrocyte enzyme activities were measured in 108 cancer patients presenting with carcinoma at one of variable sites, prior to clinical treatment. These were compared with an age- and sex-matched control group of 31 healthy volunteers.

RESULTS

Mean (+/-SD) catalase activities did not differ significantly, i.e. 0.0035 (+/-0.0015) EU/ml in carcinoma patients vs. 0.0031 (+/-0.00075) EU/ml in controls. However, mean carbonic anhydrase activities of 204 (+/-91) EU/ml in the carcinoma patients were significantly higher than the 158 (+/-35) EU/ml in controls (P value of 0.0065).

CONCLUSION

Cytosolic erythrocyte carbonic anhydrase levels may warrant further investigation as a potential peripheral marker in cancer.

Suppression of Mycobacterium tuberculosis induced reactive oxygen species (ROS) and TNF-alpha mRNA expression in human monocytes by allicin

Chronic inflammation associated with tumor necrosis factor (TNF)-alpha and reactive oxygen species (ROS) is the hallmark of tuberculosis. Mycobacterium tuberculosis (MTB) directly stimulates human monocytes to secrete TNF-alpha. We show the augmented expression of TNF-alpha mRNA in MTB-infected monocytes by cellular activation and ROS was suppressed by allicin in a dose-dependent manner. Also, allicin enhanced the glutathione peroxidase activity, which correlated inversely with the downregulation of ROS and TNF-alpha in MTB-infected monocytes. Hence, allicin may prove to be a valuable natural antioxidant in combating tuberculosis.

Systemic oxidative and antioxidative status in Chinese patients with asthma

BACKGROUND

Patients with asthma generate an increased amount of reactive oxygen species from peripheral blood cells. Reactive oxygen species produce many of the pathophysiologic changes associated with asthma and may contribute to its pathogenesis.

OBJECTIVE

We investigated changes in antioxidant enzyme activities and oxidized glutathione (glutathione disulfide; GSSG) levels in erythrocytes from a group of healthy control Chinese subjects (n=135) and patients with asthma (n=106).

METHODS

Baseline pulmonary function was measured for all subjects. Antioxidant status was evaluated by measuring erythrocyte superoxide dismutase, catalase, and glutathione peroxidase activities. Oxidative stress was also measured in terms of GSSG in erythrocytes with a kinetic microassay.

RESULTS

Patients with asthma had significantly increased erythrocyte superoxide dismutase and catalase activities compared with controls (61.10 +/- 1.30 U/g hemoglobin [Hb] vs 55.51 +/- 1.82 U/g Hb [P=.018] and 0.0637 +/- 0.0021 U/g Hb vs 0.0257 +/- 0.0120 U/g Hb [P <.001] for the asthma and control groups, respectively). Conversely, erythrocyte glutathione peroxidase activity decreased (44.21 +/- 1.33 mU/g Hb vs 50.07 +/- 1.39 mU/g Hb for the asthma and control groups, respectively; P=.003). Patients with asthma also had significantly higher GSSG levels in erythrocyte hemolysates compared with controls (167.40 +/- 2.93 micromol/L vs 44.98 +/- 0.44 micromol/L for the asthma and control groups, respectively; P <.001), indicating increased oxidative stress.

CONCLUSIONS

Asthma is accompanied by an alteration in systemic antioxidant status due to possible oxidative stress in this disease.

Selective recognition of peptide sequences by glutathione transferases: a possible mechanism for modulation of cellular stress-induced signaling pathways

Exogenous and endogenous agents including products generated by oxidative stress, chemotherapeutics and bacterial lipids, activate multiple cellular signaling pathways, resulting either in mitogenesis or in apoptosis. Glutathione transferases (GSTs) appear not only to be prominent catalysts of detoxication reactions, but also to play a pivotal role in signaling by interacting with multiple proteins in pathways induced by cellular stress. Using two peptide libraries (a 9-mer and a 15-mer) displayed on phage, novel GST-peptide interactions were identified using human GST A1-1, GST P1-1 and GST M2-2 as targets. The isolated peptides have high sequence similarity with proteins such as TRAF4-associated factor 1, G protein-coupled receptor MRGX3, tumor necrosis factor superfamily (member 9), and c-Jun N-terminal kinase 3.

Glutamine and its relationship with intracellular redox status, oxidative stress and cell proliferation/death

Glutamine is a multifaceted amino acid used for hepatic urea synthesis, renal ammoniagenesis, gluconeogenesis in both liver and kidney, and as a major respiratory fuel for many cells. Decreased glutamine concentrations are found during catabolic stress and are related to susceptibility to infections. Besides, glutamine is not only an important energy source in mitochondria, but is also a precursor of the brain neurotransmitter glutamate, which is likewise used for biosynthesis of the cellular antioxidant glutathione. Reactive oxygen species, such as superoxide anions and hydrogen peroxide, function as intracellular second messengers activating, among others, apoptosis, whereas glutamine is an apoptosis suppressor. In fact, it could contribute to block apoptosis induced by exogenous agents or by intracellular stimuli. In conclusion, this article shows evidences for the important role of glutamine in the regulation of the cellular redox balance, including brain oxidative metabolism, apoptosis and tumour cell proliferation.

Antioxidant activity levels and oxidative stress as blood markers of allergic response to drugs

Antioxidant enzymes work together in human blood cells against toxic reactive oxygen species. Although their relationship with several pathophysiologic processes has been stated, not much is known about the connection between antioxidant defence and allergy. This study was designed to determine the enzymatic activities and the oxidative indices in the blood and serum proteins in patients suffering from allergy to drugs. We hypothesize that serum and blood reactions may serve as useful clinical marker for the allergic state. We used enzymatic antioxidant activities, thiobarbituric acid reactive substances, and carbonyl contents of proteins as suitable markers. We determined superoxide dismutases, glutathione peroxidase and catalase activities in each cell type. After antihistaminics plus steroids were given as part of a protocol treatment, enzymatic antioxidant activities, thiobarbituric acid reactive substance levels, and carbonyl contents were used as recovering markers for the disease. We found a relationship between antioxidant enzymatic activities, thiobarbituric acid reactive substance levels, and carbonyl contents for allergic reactions belonging to several type I and type IV allergies, as well as cross-reactive intolerance to nonsteroidal anti-inflammatory drugs and an anaphylactoid reaction to a radiocontrast media. A similar pattern also exists for analogous allergic manifestations and disease-like status.Key words: allergy, blood, catalase, glutathione peroxidase, superoxide dismutase.

Effects of antioxidant enzymes in the molecular control of reactive oxygen species toxicology

Reactive Oxygen Species (ROS) are produced during normal cellular function. ROS include hydroxyl radicals, superoxide anion, hydrogen peroxide and nitric oxide. They are very transient species due to their high chemical reactivity that leads to lipid peroxidation and oxidation of DNA and proteins. Under normal conditions, antioxidant systems of the cell minimize the perturbations caused by ROS. When ROS generation is increased to an extent that overcomes the cellular antioxidants, the result is oxidative stress. It is now clear that several biological molecules, which are involved in cell signaling and gene regulation systems are very sensitive to redox statue of the cell. Antioxidants are substances that delay or prevent the oxidation of cellular oxidizable substrates. The various antioxidants exert their effect by scavenging superoxide, or by activating of a battery of detoxifying/defensive proteins. The prevention of oxidation is an essential process in all the aerobic organisms, as decreased antioxidant protection may lead to cytotoxicity, mutagenicity and/or carcinogenicity. This article also focuses on the mechanisms by which antioxidants and xenobiotics induce the gene expression of detoxifying enzymes. On the other hand, small molecules that mimic antioxidant enzymes are becoming new tools for the treatment of many diseases.

Chemical and biological activity of free radical 'scavengers' in allergic diseases

Reactive oxygen species (ROS) are generated constantly in vivo. They can lead to lipid peroxidation and oxidation of some enzymes, as well as protein oxidation and degradation. Cells possess several biological systems, defined as 'scavengers', to protect themselves from the radical-mediated damage. Immune cells may discharge their arsenal of toxic agents against host tissues, resulting in oxidative damage and inflammation. Therefore, free radical production and disturbance in redox status can modulate the expression of a variety of immune and inflammatory molecules, leading to inflammatory processes, both exacerbating inflammation and effecting tissue damage. Recently, abnormal immunity has been related to oxidative imbalance, and antioxidant functions are linked to anti-inflammatory and/or immunosuppressive properties. Currently, allergy is one of the most important human diseases. We studied the role of the primary antioxidant defence system, constituted by the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase, protecting cells from toxic oxygen. We analyzed how they are involved in blood cells detoxification, and how the imbalance of reactive oxygen species is related to inflammation in allergic diseases by affecting immune cells. Finally, we discuss the published data that relates anti-free radical therapy to the management of human allergic diseases.