Antioxidant capacities of ascorbic acid, uric acid, alpha-tocopherol, and bilirubin can be measured in the presence of another antioxidant, serum albumin

New look at the metabolism of nonsteroidal anti-inflammatory drugs: influence on human serum albumin antioxidant activity

Body's homeostasis is dependent on many factors, such as maintaining balance between free radicals formation and degradation. Human serum albumin (HSA) also plays an important role in homeostasis. The aim of this study was thermodynamic analysis of the interaction between ketoprofen (KET), naproxen (NPX), diclofenac (DIC) and HSA, as well as the effect of drug-albumin binding on HSA antioxidant activity using calorimetric and spectrophotometric techniques. Based on the calorimetric analysis it has been shown that accompanied by hydrophobic interaction drugs-albumin binding is an exoenergetic reaction. All analyzed drugs and HSA showed the ability to react with free radicals such as a radical cation, formed as a result of the reaction between 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and potassium persulfate (K₂S₂O₈). Using ABTS assay a synergistic effect of ketoprofen (KET) and naproxen (NPX) on HSA antioxidant activity was observed while the effect of diclofenac (DIC) binding with albumin was probably additive. Because some medications including KET, NPX and DIC belong to over the counter (OTC) non-steroidal anti-inflammatory drugs (NSAIDs), it is necessary to understand their influence on HSA antioxidant activity.Communicated by Ramaswamy H. Sarma.

New Synthetic Quinoline (Qui) Derivatives as Novel Antioxidants and Potential HSA's Antioxidant Activity Modulators-Spectroscopic Studies

The antioxidant activity of drugs, as well as the influence of drugs on the activity of endogenous antioxidant mechanisms in the human body is of great importance for the course of the disease and the treatment process. Due to the need to search for new therapeutic methods, the study of newly synthesized substances with potential therapeutic activity is necessary. This study aimed to designate some properties and characteristic parameters of new, synthetic quinoline three derivatives-1-methyl-3-allylthio-4-(4'-methylphenylamino)quinolinium bromide (Qui1), 1-methyl-3-allylthio-4-(3'-hydroxyphenylamino)quinolinium bromide (Qui2) as well as 1-methyl-3-allylthio-4-(4'-hydroxyphenylamino)quinolinium bromide (Qui3), including their antioxidant properties, as well as to analyse their activity as the potential modulators of Human Serum Albumin (HSA) antioxidant activity. In order to achieve the goal of the study, spectroscopic methods such as UV-Vis and circular dichroism (CD) spectroscopy have been used and based on the obtained data only slight and probably some surface interaction of quinoline derivatives (Qui1-Qui3) with HSA have been observed. The effect of Qui1-Qui3 on the HSA secondary structure was also insignificant. All analysed quinine derivatives have antioxidant activity against ABTS cation radical, in turn against DPPH radical, only Qui3 has noticeable antioxidant potential. The highest reduction potential by Qui3 as well as (Qui3 + HSA)_complex has been shown. Qui3 mixed with HSA has mostly the synergistic effect against DPPH, ABTS and FRAP, while Qui1 and Qui2 in the presence of HSA mostly have a synergistic and additive effect towards ABTS, respectively. Based on the obtained results it can be concluded that Qui2 and Qui3 can be considered potential modulators of HSA antioxidant activity.

Comparison of Losartan and Furosemide Interaction with HSA and Their Influence on HSA Antioxidant Potential

Serum albumin (HSA) is the most important protein in human body. Due to the antioxidant activity, HSA influences homeostasis maintenance and transport of drugs as well as other substances. It is noteworthy that ligands, such as popular drugs, modulate the antioxidant activity of HSA. The aim of this study was to analyze the influence of losartan (LOS) and furosemide (FUR) on HSA antioxidant properties as well as the interaction between these drugs and protein using calorimetric and spectroscopic methods. LOS and FUR showed the high affinity for human serum albumin, and the binding reactions between them were spontaneous and exothermic. LOS and FUR, separately and together in the system, have no significant impact on the secondary HSA structure; however they have significant impact on the tertiary HSA structure. LOS and FUR mixed with HSA have the ability to scavenge free radicals, and the ligand(s)-HSA interactions were synergistic.

Common and Novel Markers for Measuring Inflammation and Oxidative Stress Ex Vivo in Research and Clinical Practice-Which to Use Regarding Disease Outcomes?

Many chronic conditions such as cancer, chronic obstructive pulmonary disease, type-2 diabetes, obesity, peripheral/coronary artery disease and auto-immune diseases are associated with low-grade inflammation. Closely related to inflammation is oxidative stress (OS), which can be either causal or secondary to inflammation. While a low level of OS is physiological, chronically increased OS is deleterious. Therefore, valid biomarkers of these signalling pathways may enable detection and following progression of OS/inflammation as well as to evaluate treatment efficacy. Such biomarkers should be stable and obtainable through non-invasive methods and their determination should be affordable and easy. The most frequently used inflammatory markers include acute-phase proteins, essentially CRP, serum amyloid A, fibrinogen and procalcitonin, and cytokines, predominantly TNFα, interleukins 1β, 6, 8, 10 and 12 and their receptors and IFNγ. Some cytokines appear to be disease-specific. Conversely, OS-being ubiquitous-and its biomarkers appear less disease or tissue-specific. These include lipid peroxidation products, e.g., F2-isoprostanes and malondialdehyde, DNA breakdown products (e.g., 8-OH-dG), protein adducts (e.g., carbonylated proteins), or antioxidant status. More novel markers include also -omics related ones, as well as non-invasive, questionnaire-based measures, such as the dietary inflammatory-index (DII), but their link to biological responses may be variable. Nevertheless, many of these markers have been clearly related to a number of diseases. However, their use in clinical practice is often limited, due to lacking analytical or clinical validation, or technical challenges. In this review, we strive to highlight frequently employed and useful markers of inflammation-related OS, including novel promising markers.

Review of the Literature Examining the Association of Serum Uric Acid with Osteoporosis and Mechanistic Insights into Its Effect on Bone Metabolism

BACKGROUND AND OBJECTIVE

Osteoporosis is a common bone disorder that increases susceptibility to fragility bone fractures. The clinical and public health repercussions of osteoporosis are huge due to the morbidity, mortality, and cost of medical care linked with fragility fractures. Clinical assessment of osteoporotic risk factors can help to identify candidates at an early stage that will benefit from medical intervention and potentially lowering the morbidity and mortality seen with fractures and complications. Given this, research is ongoing to evaluate the association of osteoporosis with some novel or less well-studied risk factors/bio-markers such as uric acid (UA).

DISCUSSION

Uric acid's antioxidant activity has been proposed to be one of the factors responsible for increasing longevity and lowering rates of age-related cancers during primate evolution, the level of which increased markedly due to loss of uricase enzyme activity (mutational silencing). Accumulated evidence shows that oxidative stress is the fundamental mechanism of age-related bone loss and acts via enhancing osteoclastic activity and increasing bone resorption. Antioxidant substances such as ascorbic acid scavenge free radicals are positively related to bone health. Thus, it is hypothesized that uric acid holds bone-protective potential owing to its potent antioxidative property. Several correlation studies have been conducted globally to investigate the relationship between serum uric acid with bone mineral density and osteoporosis. Few pre-clinical studies have tried to investigate the interaction between uric acid and bone mineral density and reported important role played via Runt-related transcription factor 2 (RUNX2)/core-binding factor subunit alpha-1 (CBF-alpha-1), Wingless-related integration site (Wnt)-3a/β-catenin signaling pathway and 11β Hydroxysteroid Dehydrogenase type 1.

CONCLUSION

In this review, the authors provided a comprehensive summary of the literature related to association studies reported in humans as well work done until date to understand the potential cellular and molecular mechanisms that interplay between uric acid and bone metabolism.

Association between Serum Uric Acid and Oxidative Stress in Korean Adults

Background

Oxidative stress is implicated in the pathogenesis and development of lifestyle-related diseases. In the present study, we evaluated the correlation between the serum uric acid (UA) levels and oxidative status in Korean adults.

Methods

The subjects were 5,093 individuals (2,041 women and 3,052 men) who underwent a health checkup between June 2012 and December 2016. Oxidative stress levels (derivatives of reactive oxygen metabolites [d-ROMs]) and antioxidant potential (biological antioxidant potential [BAP]) were measured. Metabolic markers, including UA, were also examined.

Results

Higher serum UA levels were associated with decreased levels of d-ROMs (P<0.05). The UA levels were positively associated with BAP levels (P<0.001).

Conclusion

Serum UA is related to oxidative status, especially antioxidant capacity, in Korean adults; UA may play a role in antioxidant defense systems in humans.

Serum Bilirubin and Albumin in Anti-N-Methyl-D-Aspartate Receptor Encephalitis

BACKGROUND AND OBJECTIVE

Low serum levels of bilirubin and albumin are associated with multiple autoimmune diseases, but their role in anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is unknown.

METHODS

Serum bilirubin and albumin levels were evaluated in 60 patients with anti-NMDAR encephalitis, 50 cryptococcal encephalitis, and 145 healthy controls (CTLs). Of the 60 anti-NMDAR encephalitis patients, 30 had a follow-up evaluation at 3 months after admission.

RESULTS

Serum bilirubin and albumin levels were both significantly lower in anti-NMDAR encephalitis than in CTLs, and serum bilirubin levels were significantly lower in anti-NMDAR encephalitis than in cryptococcal encephalitis. Serum bilirubin levels were significantly lower in patients with psychiatric symptoms, with severe impairment, and with limited responses to treatment than those without psychiatric symptoms, with mild impairment, and with favorable responses to treatment, respectively. A follow-up evaluation of 30 patients revealed that the modified Rankin Scale scores were significantly decreased after treatment. Serum bilirubin significantly associated with serum albumin, and plasma hemoglobin.

CONCLUSIONS

Our results revealed for the first time an association between the serum levels of bilirubin in the anti-NMDAR encephalitis. Further studies investigating the role of bilirubin and albumin in anti-NMDAR encephalitis are required.

Preanalytic of total antioxidant capacity assays performed in serum, plasma, urine and saliva

The investigation of oxidative stress (OS), its mechanisms and connections with human diseases, is a topic of interest with more than 36,000 PubMed citations to date. The OS can be approached either from the perspective of pro-oxidation, either of anti-oxidation, and both can be investigated considering individual chemical constituents or their pooled effect. Actually, as it is for any laboratory assay, whatever source of variability introduces a bias potentially undermining the test results regardless of its application. In this regard, the effect of sample collection, handling and storage - that collectively constitute the preanalytical phase - on the likeliness of the measured value represent a major challenge for any researcher. In this review, we will deal with methods devised to assess the so-called total antioxidant capacity (TAC), which represents the sinking capability expressed toward a given load of pro-oxidant species. Thus, it will be presented the information available to date on the preanalytical phase of TAS assessment, focusing on the issues that strictly concern the preservation of antioxidants within the specimen. Obviously, preanalytic should represent a first concern in any laboratory research, to which this work could contribute giving practical indications and raising the researchers' awareness about the issue.

Relationship between serum uric acid and serum oxidative stress markers in the Japanese general population

BACKGROUND

Increased production of reactive oxygen species is a condition that is associated with, and plays a role in the progression of, various disorders such as hypertension, atherosclerosis, and diabetes.

PURPOSE

To assess in vivo oxidative stress levels and antioxidant potential and to analyze the relationship with serum uric acid (UA) levels.

METHODS AND RESULTS

Oxidative stress levels (derivatives of reactive oxygen metabolites, d-ROMs) and antioxidant potential (biological antioxidant potential, BAP) were measured in individuals who underwent a general health screening test, and data were analyzed from 8,025 individuals (2,953 women and 5,072 men) who were free from UA-lowering medication. Higher serum UA levels were associated with increased levels of d-ROMs in both genders, and this trend was more prominent in women. In addition, higher UA levels were also associated with higher BAP in both genders, although the dose dependence was not apparent in men. These associations remained statistically significant after adjusting for age, blood pressure, renal function, albuminuria, C-reactive protein, and insulin resistance index.

CONCLUSIONS

In individuals who underwent general health screening, serum UA levels were positively associated with both d-ROMs and BAP levels. Whether lowering of UA by lifestyle modification or by medication alters d-ROM/BAP levels awaits further investigations. .

Significance of measuring oxidative stress in lifestyle-related diseases from the viewpoint of correlation between d-ROMs and BAP in Japanese subjects

In recent years, oxidative stress has been postulated to be an important factor in the pathogenesis and development of lifestyle-related diseases. In this study, we investigated the association between the derivatives of reactive oxygen metabolites (d-ROMs), as an index of products of reactive oxygen species (ROS), and biological antioxidant potential (BAP), as an index of antioxidant potential. We also investigated the associations between d-ROMs or BAP and the risk factors for lifestyle-related diseases or metabolic syndrome-associated factors to evaluate their usefulness in preventive medicine. There were 442 subjects who underwent health checkup examination in our facilities. In addition to standard medical checkup items, we analyzed d-ROMs, BAP, brachial-ankle pulse wave velocity, high-sensitivity C-reactive protein level and visceral fat area (VFA) visualized on a computed tomography scan. The mean d-ROM value in females was significantly higher than that in males. There was a positive correlation between the d-ROM and VFA levels. On correlation analysis, there was a negative correlation between the d-ROM and creatinine levels. As factors that influence d-ROMs, the level of VFA was selected, suggesting the significance of oxidative stress measurement with d-ROMs. In addition, there was a positive correlation between d-ROMs and BAP values. Further research is required to resolve whether increased production of ROS or the antioxidant potential that can compensate for such an increase of ROS is more important in vivo.

Redox status of acute pancreatitis as measured by cyclic voltammetry: initial rodent studies to assess disease severity

OBJECTIVE

To determine whether serum antioxidant capacity as measured by the electrochemical technique cyclic voltammetry could be used to resolve differences in the severity of an inflammatory disease such as acute pancreatitis.

DESIGN

Experimental animal study.

SETTING

Animal laboratory, Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, New Zealand.

SUBJECTS

Male Wistar rats.

INTERVENTIONS

A total of 48 inbred male Wistar rats were studied in five experimental groups. Group 1 (baseline reference, immediate euthanasia, n = 14) had no surgical intervention. Group 2 (sham, n = 9) had identical surgical procedures to the pancreatitis groups except for the intraductal infusion. Groups 3-5 (n = 9, n = 10, and n = 6, respectively) had acute pancreatitis induced by the pancreatic intraductal infusion of 3%, 4%, or 5% sodium taurocholate, respectively. Groups 2-5 were killed after 12 hrs.

MEASUREMENTS AND MAIN RESULTS

Cyclic voltammetry involves scanning the voltage of a working electrode while recording the anodic current produced as the low molecular weight antioxidants in the solution are oxidized on the surface of the working electrode. The current produced is proportional to the combined concentration of the antioxidants. There was a significant positive correlation of the first cyclic voltammetric peak maximum with pancreatic histologic severity (Spearman's r = .51, p = .007) and with a number of other markers of systemic severity, notably bicarbonate (r = -.57, p = .002), base excess (r = -.65, p < .001), urea (r = .68, p < .001), and calcium (r = -.60, p = .008). The first cyclic voltammetric peak maximum was superior at indicating the severity of the disease state compared with a standard method of total antioxidant capacity measurement.

CONCLUSIONS

In experimental pancreatitis, the first cyclic voltammetric peak maximum showed significant correlations with histologic and systemic indices of severity. Further clinical studies are now needed to define the role of cyclic voltammetry in monitoring the progression of this and other severe illness in the critical care setting.

A preliminary analysis of within-subject variation in human serum oxidative stress parameters as a function of time

The aim of this study was to determine variability at both levels of two serum oxidative stress markers (lipid peroxides and carbonyl concentration) as well as total antioxidant capacity in humans as a function of time. Assays for oxidative stress and antioxidant capacity were repeated in the same individuals three times daily on four particular days over a period of 51 days. The results show a high variation within subject in the concentration of these markers not only when comparing the different days (the morning values can change up to 98%), but also during the day, where the evening values can increase up to 84% with respect to those of the morning. This suggests that several measurements are required to establish the typical oxidative stress status of an individual before studying the potential effect of treatments that possibly influence oxidative damage. The observed changes during the day allowed us to speculate about the optimum temporal antioxidant delivery regimes that minimize the imbalance between oxidants and antioxidants. In the study, only a few general aspects of basic lifestyle habits were controlled. However, the levels of these markers are sensitive to possibly a group of factors. This points to the necessity of using a much bigger population to establish the possible contribution of each lifestyle habits to the concentration of the markers.

Evidence for oxidative stress at elevated plasma thiol levels in chronic exposure to carbon disulfide (CS2) and coronary heart disease

OBJECTIVES

Oxidative stress in plasma may be promoted by plasma thiols such as homocysteine. However, other thiols such as glutathione may also exert antioxidant effects in vitro and in vivo. To further investigate whether plasma thiols act as prooxidants or antioxidants, we compared plasma oxidative status in patients with coronary heart disease (CHD) and in subjects occupationally exposed to carbon disulfide (CS(2)).

METHODS

Fifty-five subjects chronically exposed to CS(2), 53 CHD patients, and 52 healthy controls were examined. To assess plasma oxidative status, concentrations of thiobarbituric reactive substances (TBARS) and total antioxidative capacity (TAC), as well as ferritin and ceruloplasmin were determined. Antioxidative reserve was assessed by the determination of vitamine E, uric acid, superoxide dismutase, catalase, and glutathion peroxidase. In addition, protein and non-protein plasma thiol levels were measured.

RESULTS

Patients in both groups had increased levels of plasma thiols as compared to controls: CS(2)-exposed subjects presented with increased levels of thiols associated with plasma proteins, whereas CHD patients presented with elevated total homocysteine and cysteine levels. TBARS were significantly increased and TAC was significantly decreased both in CS(2)-exposed subjects and in CHD patients. In addition decreased activity of glutathione peroxidase, an antioxidative enzyme inhibited by thiol-containing compounds, was noted in both groups.

CONCLUSION

These results demonstrate that regardless of their metabolic origin increased thiols are associated with increased oxidative stress in plasma.

Cytostatic therapy and blood antioxidants/prooxidants balance in acute myeloblastic leukemia patients

To analyze the effects of conventional polychemotherapy of acute myeloblastic leukemia (AML) patients on the prooxidants/antioxidants balance in plasma total antioxidant status (TAS) and a single plasma antioxidant — uric acid (UA) were measured. Lipid peroxidation was assessed by malonedialdehyde (MDA) content. Total serum iron was monitored as a potential source of nontransferrin-bound iron with a role in initiation of oxidative burst. A group of patients in the acute phase of AML (group A) and a group of patients in complete remission of AML (group B) were studied. A strong correlation between UA values and TAS (r = 0.8 for group A, r = 0.9 for group B) was revealed in the course of the treatment. Strong negative correlation (r = −0.9) between TAS and MDA was shown for both groups. Total iron significantly increased in the course of chemotherapy. We have established that polychemotherapy leads to the consumption of antioxidants and increased lipid peroxidation in AML patients. An appropriate supplementation with antioxidants at the end of the polychemotherapy treatment could be considered.