Are Advanced Oxidation Protein Products (AOPPs) Levels Altered in Neuropsychiatric Disorders? An Integrative Review

Neuropsychiatric disorders such as major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia (SZ) are considered a public health problem since it interferes in personal relationships and at work. The pathophysiological mechanisms of these mental disorders are still not completely understood. The variety and heterogeneity of symptoms, as well as the absence of biomarkers, make the diagnosis, prognosis, and treatment of these disorders difficult. However, oxidative stress appears to play a role in the pathophysiology of these diseases. In this context, advanced oxidation protein products (AOPPs) are considered a biomarker of protein oxidative damage and have been associated with neuroinflammatory diseases. In patients with neuropsychiatric disorders, increased levels of AOPPs were associated with the severity of symptoms and decreased quality of life. Thus, the objective of this integrative review is to investigate and discuss the relationship between AOPPs levels and MDD, BD, and SZ. Different databases were consulted and approximately 112 scientific articles were found relating AOPPs and psychiatric disorders. In the majority of studies, the blood levels of AOPPs were increased in MDD, BD, and SZ and associated with the severity of the disorders. Although the association of this marker with the risk of developing one of these mental disorders is more uncertain, some studies have suggested this relationship. Of the twenty-four studies highlighted, only four did not find significant differences in AOPPs levels in patients with the disorders mentioned. In summary, it may be suggested that the assessment of AOPPs levels can be a useful tool in the evaluation of neuropsychiatric disorders, at least for prognostic evaluation. However, the role of this biomarker in the pathophysiology of mental disorders is still unclear, as well as whether reducing its levels represents a potential therapeutic strategy.

Increased levels of advanced oxidation protein products (AOPPs) were associated with nociceptive behavior and clinical scores in an experimental progressive autoimmune encephalomyelitis model (PMS-EAE)

Multiple sclerosis (MS) is a neurodegenerative disease that affects the central nervous system (CNS) generating neuropathic pain and anxiety. Primary progressive MS (PPMS) is the most disabling clinical form, and the patients present an intense neurodegenerative process. In this context, the advanced oxidation protein products (AOPPs) are oxidized compounds and their accumulation in plasma has been related to clinical disability in MS patients. However, the involvement of AOPPs in neuropathic pain- and anxiety-like symptoms was not previously evaluated. To assess this, female mice C57BL/6J were used to induce progressive experimental autoimmune encephalomyelitis (PMS-EAE). Clinical score, weight, strength of plantar pressure, rotarod test, mechanical allodynia, and cold hypersensitivity were evaluated before induction (baseline) and on days 7th , 10th , and 14th post-immunization. We assessed nest building, open field, and elevated plus-maze tests 13 days post-immunization. Animals were killed at 14 days post-immunization; then, AOPPs levels, NADPH oxidase, and myeloperoxidase (MPO) activity were measured in the prefrontal cortex, hippocampus, and spinal cord samples. The clinical score increased 14th post-immunization without changes in weight and mobility. Reduced paw strength, mechanical allodynia, and cold allodynia increased in the PMS-EAE animals. PMS-EAE mice showed spontaneous nociception and anxiety-like behavior. AOPPs concentration, NADPH oxidase, and MPO activity increase in CNS structures. Multivariate analyses indicated that the rise of AOPPs levels, NADPH oxidase, and MPO activity influenced the clinical score and cold allodynia. Thus, we indicated the association between non-stimuli painful perception, anxiety-like, and CNS oxidative damage in the PMS-EAE model.

Inflammatory markers and depression in Parkinson's disease: a systematic review

BACKGROUND

Parkinson's disease (PD) patients experience non-motor symptoms (NMS), which may appear before motor manifestations. The most common NMS is depression, affecting about 30-40% of PD patients. Both PD and depression are associated with an increased inflammatory burden, with studies showing elevation of diverse inflammatory markers in patients with both conditions.

METHODS

A systematic review was conducted in PubMed and PsycINFO databases to investigate what inflammatory markers are associated with PD depression (PDD). Only studies in English that measured inflammatory markers and analyzed against depression scores in PD patients were included.

RESULTS

A total of 1132 articles were retrieved, and 14 entries were found to be eligible. Twelve were cross-sectional studies, one was a cohort, and one was a non-randomized controlled trial. IL-17A was the only marker strongly associated with PDD, while studies assessing sIL-2R and serum amyloid A found a moderate correlation. C-reactive protein, IL-10, tumor necrosis factor-α, monocyte chemoattractant protein-1, and IL-6 yielded conflicting results. Their possible roles in PDD are discussed. PDD was also related to longer disease duration and other NMS, such as anxiety, fatigue, dementia, REM sleep behavior disorder, and autonomic dysfunction.

CONCLUSION

We suggest that these markers may be used for distinguishing isolated depression from that related to neurodegeneration, especially in individuals that concurrently present with other known prodromal symptoms of PD and other α-synucleinopathies. However, future prospective studies are warranted to confirm this hypothesis.

Microglia and HPA axis in depression: An overview of participation and relationship

Objectives: This narrative review article provides an overview on the involvement of microglia and the hypothalamic-pituitary-adrenal (HPA) axis in the pathophysiology of depression, as well investigates the mutual relationship between these two entities: how microglial activation can contribute to the dysregulation of the HPA axis, and vice versa.Methods: Relevant studies and reviews already published in the Pubmed electronic database involving the themes microglia, HPA axis and depression were used to meet the objectives.Results: Exposition to stressful events is considered a common factor in the mechanisms proposed to explain the depressive disorder. Stress can activate microglial cells, important immune components of the central nervous system (CNS). Moreover, another system involved in the physiological response to stressors is the hypothalamic-pituitary-adrenal (HPA) axis, the main stress response system responsible for the production of the glucocorticoid hormone (GC). Also, mediators released after microglial activation can stimulate the HPA axis, inducing production of GC. Likewise, high levels of GCs are also capable of activating microglia, generating a vicious cycle.Conclusion: Immune and neuroendocrine systems seems to work in a coordinated manner and that their dysregulation may be involved in the pathophysiology of depression since neuroinflammation and hypercortisolism are often observed in this disorder.

LOWER ANTIDEPRESSANT RESPONSE TO FLUOXETINE IS ASSOCIATED WITH ANXIETY-LIKE BEHAVIOR, HIPPOCAMPAL OXIDATIVE IMBALANCE, AND INCREASE ON PERIPHERAL IL-17 AND IFN-γ LEVELS

Major depression is a leading contributor to the global burden of disease. This is mainly related to the disorder chronic and recurrent nature, and to high rates of refractoriness to treatment. Limited efficacy with currently available antidepressants highlights the need for more effective options for treating drug-resistant patients and emphasizes the importance of developing specific preclinical models for treatment-resistant populations. Treatment-resistant depression (TRD) is commonly defined as failure to respond to two or more trials of antidepressants. In this study, we investigated the effect of fluoxetine treatment for fourteen days on the depressive-like behavior and the oxidative and inflammatory parameters of mice submitted to chronic corticosterone administration. After 21 days of subcutaneous corticosterone administration (20mg/Kg/day) and 14 days of oral fluoxetine treatment (10mg/Kg/day, started on day 7 of induction protocol), we separated animals into two groups according to the tail suspension test's (TST) results: antidepressant responders (good response to antidepressant, GRA) and non-responders (resistance to antidepressant, AR). Forced swimming test (FST), elevated plus maze test (EPMT), and open field test (OFT) were performed. We found that animals classified as AR (i.e., those with higher immobility values in the TST) demonstrated anxiety-like behavior in the EPMT, increased H₂O₂ levels, and decreased catalase activity in the hippocampus, as well as increased serum levels of IL-17 and IFN-γ. Our findings suggest that a redox imbalance in the hippocampus, combined with increased levels of peripheral IL-17 and INF-γ, may be involved with an impaired response to fluoxetine.

Periorbital Nociception in a Progressive Multiple Sclerosis Mouse Model Is Dependent on TRPA1 Channel Activation

Headaches are frequently described in progressive multiple sclerosis (PMS) patients, but their mechanism remains unknown. Transient receptor potential ankyrin 1 (TRPA1) was involved in neuropathic nociception in a model of PMS induced by experimental autoimmune encephalomyelitis (PMS-EAE), and TRPA1 activation causes periorbital and facial nociception. Thus, our purpose was to observe the development of periorbital mechanical allodynia (PMA) in a PMS-EAE model and evaluate the role of TRPA1 in periorbital nociception. Female PMS-EAE mice elicited PMA from day 7 to 14 days after induction. The antimigraine agents olcegepant and sumatriptan were able to reduce PMA. The PMA was diminished by the TRPA1 antagonists HC-030031, A-967079, metamizole and propyphenazone and was absent in TRPA1-deficient mice. Enhanced levels of TRPA1 endogenous agonists and NADPH oxidase activity were detected in the trigeminal ganglion of PMS-EAE mice. The administration of the anti-oxidants apocynin (an NADPH oxidase inhibitor) or alpha-lipoic acid (a sequestrant of reactive oxygen species), resulted in PMA reduction. These results suggest that generation of TRPA1 endogenous agonists in the PMS-EAE mouse model may sensitise TRPA1 in trigeminal nociceptors to elicit PMA. Thus, this ion channel could be a potential therapeutic target for the treatment of headache in PMS patients.

Advanced Oxidative Protein Products Role in Multiple Sclerosis: a Systematic Review and Meta-analysis

Multiple sclerosis (MS) is an autoimmune-mediated disease that damages the central nervous system. MS pathophysiological features are not entirely understood, but the increase of reactive oxygen species (ROS) possibly causes myelin and oligodendrocyte degeneration. ROS-increased production generates new compounds through oxidative modifications, including advanced oxidative protein products (AOPPs). The AOPPs are oxidative stress biomarkers and inflammatory mediators commonly formed by hypochlorous acid oxidative action on albumin. Considering that AOPPs accumulation produces ROS and induces neuronal apoptosis, these may represent a new target for drug development to MS treatment and a possible biomarker to monitor the severity of the disease. Thus, this review aims to investigate if there is an alteration in the AOPPs levels in MS and its possible involvement in patient disability. The second objective is to analyze whether drugs or compounds used in MS treatment could modify the AOPPs levels. The protocol was registered in PROSPERO (CRD42020203268). The databases' search yielded 327 articles. We excluded 259 duplicated articles and evaluated 68 articles by the title and abstract. We full-text analyzed 17 articles and included 13 articles. The AOPPs levels were increased in not-treated MS patients. Furthermore, the increase in disability status was associated with AOPPs accumulation in not-treated MS patients. Additionally, the AOPPs levels were reduced in MS patients after treatment. Therefore, AOPPs seem to play a role in MS pathophysiology and may become a new target for drug development and help MS diagnosis or treatment follow-up.

TRPA1 involvement in depression- and anxiety-like behaviors in a progressive multiple sclerosis model in mice

Progressive multiple sclerosis (PMS) is a neurological disease associated with the development of depression and anxiety, but treatments available are unsatisfactory. The transient receptor potential ankyrin 1 (TRPA1) is a cationic channel activated by reactive compounds, and the blockage of this receptor can reduce depression- and anxiety-like behaviors in naive mice. Thus, we investigated the role of TRPA1 in depression- and anxiety-like behaviors in a PMS model in mice. PMS model was induced in C57BL/6 female mice by the experimental autoimmune encephalomyelitis (EAE). Nine days after the PMS-EAE induction, behavioral tests (tail suspension and elevated plus maze tests) were performed to verify the effects of sertraline (positive control), selective TRPA1 antagonist (A-967,079), and antioxidants (α-lipoic acid and apocynin). The prefrontal cortex and hippocampus were collected to evaluate biochemical and inflammatory markers. PMS-EAE induction did not cause locomotor changes but triggered depression- and anxiety-like behaviors, which were reversed by sertraline, A-967,079, α-lipoic acid, or apocynin treatments. The neuroinflammatory markers (AIF1, GFAP, IL-1β, IL-17, and TNF-α) were increased in mice's hippocampus. Moreover, this model did not alter TRPA1 RNA expression levels in the hippocampus but decrease TRPA1 levels in the prefrontal cortex. Moreover, PMS-EAE induced an increase in NADPH oxidase and superoxide dismutase activities and TRPA1 endogenous agonist levels (hydrogen peroxide and 4-hydroxynonenal). TRPA1 plays a fundamental role in depression- and anxiety-like behaviors in a PMS-EAE model; thus, it could be a possible pharmacological target for treating these symptoms in PMS.

Nociceptive mechanisms involved in the acute and chronic phases of a complex regional pain syndrome type 1 model in mice

Complex regional pain syndrome I (CRPS-I) is a chronic painful pathology still undertreated. CTK 01512-2 is a recombinant version of the spider peptide Phα1β, and it functions as a voltage-gated calcium channel blocker and a transient receptor potential ankyrin 1 (TRPA1) antagonist with antinociceptive effect in different pain models. Here, we investigate the mechanisms involved in the acute and chronic nociceptive phases of a model of CPRS-I in mice and assess the antinociceptive effect of CTK 01512-2 using this model. Adult male and female mice C57BL/6 (20-30 g) were used to determine mechanical (von Frey test) or cold (acetone test) allodynia induction. Inflammatory parameters (serum and tibial nerve lactate levels, hind paw temperature and edema, or tissue cell infiltration) were evaluated after chronic post-ischemia pain (CPIP, a model of CPRS-I) induction. Anti-inflammatory and anti-neuropathic drugs or CTK 01512-2 were tested. First, we detected that CPIP-induced mechanical and cold allodynia in male and female mice in a similar way. In the acute phase (1 day after CPIP), an increase in inflammatory parameters were observed, as well as the anti-allodynic effect of anti-inflammatory compounds. In the chronic phase (17 days after CPIP), mice exhibited mechanical and cold allodynia, and anti-neuropathic drugs induced antinociception, while no inflammatory alterations were found. CTK 01512-2 reversed the CPIP allodynic effect in both nociceptive phases. Thus, this CPRS-I model can be used to understand the mechanisms involved in CPRS-I induced pain and inflammation. Besides, we observed that CTK 01512-2 has a valuable antinociceptive effect in this pain model.

TsNTxP, a non-toxic protein from Tityus serrulatus scorpion venom, induces antinociceptive effects by suppressing glutamate release in mice

Neuropathic pain is a common type of chronic pain caused by trauma or chemotherapy. However, this type of pain is undertreated. TsNTxP is a non-toxic protein isolated from the venom of the scorpion Tityus serrulatus, and it is structurally similar to neurotoxins that interact with voltage-gated sodium channels. However, the antinociceptive properties of this protein have not been characterized. The purpose of this study was to investigate the antinociceptive effects of TsNTxP in acute and neuropathic pain models. Male and female Swiss mice (25-30 g) were exposed to different models of acute pain (tail-flick test and nociception caused by capsaicin intraplantar injection) or neuropathic pain (chronic pain syndrome induced by paclitaxel or chronic constriction injury of the sciatic nerve). Hypersensitivity to mechanical or cold stimuli were evaluated in the models of neuropathic pain. The ability of TsNTxP to alter the release of glutamate in mouse spinal cord synaptosomes was also evaluated. The results showed that TsNTxP exerted antinociceptive effects in the tail-flick test to a thermal stimulus and in the intraplantar capsaicin administration model. Furthermore, TsNTxP was non-toxic and exerted antiallodynic effects in neuropathic pain models induced by chronic constriction injury of the sciatic nerve and administration of paclitaxel. TsNTxP reduced glutamate release from mouse spinal cord synaptosomes following stimulation with potassium chloride (KCl) or capsaicin. Thus, this T. serrulatus protein may be a promising non-toxic drug for the treatment of neuropathic pain.

ALA16VAL-MnSOD gene polymorphism and stroke: Association with dyslipidemia and glucose levels

Stroke risk has been associated to the progression of carotid plaques due to high glucose levels and lipid accumulation, which are greatly associated to cerebral injury, brain oxidative stress, and apoptosis. The ALA16VAL-MnSOD gene single nucleotide polymorphism (SNP) has shown to modulate risk factors of several metabolic and vascular diseases, such as blood glucose (GLU) and lipid levels. However, the association of these factors in stroke patients has not been studied to date. Thus, we evaluated the influence of the Ala16Val-MnSOD SNP on lipid profile, GLU levels, oxidative and DNA damage of 44 patients in a late phase of stroke (>6months). The statistical analysis showed a greater proportion of VV carries in stroke patients. The results also indicated that stroke patients had higher cholesterol (CHO) and GLU levels when compared to healthy counterparts. Interestingly, V allele carriers with stroke showed higher levels of CHO and GLU when compared to AA stroke and healthy counterparts. Our findings suggest that oxidative stress markers are still increased even after 6 months of cerebral injury. Furthermore, we propose that the Ala16Val-MnSOD SNPs may contribute to hypercholesterolemia and higher GLU levels, increasing the risk to neurovascular events that may lead to stroke.

Fenton Reaction-Generated Advanced Oxidation Protein Products Induces Inflammation in Human Embryonic Kidney Cells

Fenton reaction is a new mechanism able to generate advanced oxidation protein products (AOPPs) by exposing the human serum albumin to the Fenton system. Here, we characterized the effects of Fenton reaction-generated advanced oxidation protein products (AOPP-FR) on the gene transcription of the nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2), and interleukin-6 (IL-6) in human embryonic kidney cells (HEK 293). To investigate the effects of AOPP-FR and AOPP-HOCl on transcription of inflammatory genes, the NF-κB, COX-2, and IL-6 luciferase promoter activities were analyzed. AOPP-FR and AOPP-HOCl were able to induce the activation of the gene transcription of NF-κB, COX-2, and IL-6 in HEK 293 cells. However, the effects of AOPP-FR were significantly higher than the effects of AOPP-HOCl in relation to COX-2 and IL-6. AOPP-FR induces the activation of the gene transcription of NF-κB, COX-2, and IL-6 and may represent a novel pathogenic mediator of inflammation in kidney.

In vitro oxidation of fibrinogen promotes functional alterations and formation of advanced oxidation protein products, an inflammation mediator

Fibrinogen (FB) is a soluble blood plasma protein and is a key molecule involved in coagulation. Oxidative modification of proteins, such as the formation of advanced oxidation protein products (AOPP), a heterogeneous family of protein compounds structurally modified and derived from oxidative stress, may be associated with the pathophysiology of a number of chronic inflammatory diseases. Therefore, the aim of this study was to determine whether the formation of this mediator of inflammation occurs from FB and whether its generation is associated with structural changes. Results of the present study suggest that the oxidation of FB may provoke the formation of AOPP, which in turn, may promote functional alterations in FB, thus causing changes in its structural domains and increasing its procoagulant activity.

Iron and Oxidative Stress in Parkinson's Disease: An Observational Study of Injury Biomarkers

Parkinson's disease (PD) is characterized by progressive motor impairment attributed to progressive loss of dopaminergic neurons in the substantia nigra (SN) pars compacta. In addition to an accumulation of iron, there is also an increased production of reactive oxygen/nitrogen species (ROS/RNS) and inflammatory markers. These observations suggest that iron dyshomeostasis may be playing a key role in neurodegeneration. However, the mechanisms underlying this metal-associated oxidative stress and neuronal damage have not been fully elucidated. To determine peripheral levels of iron, ferritin, and transferrin in PD patients and its possible relation with oxidative/nitrosative parameters, whilst attempting to identify a profile of peripheral biomarkers in this neurological condition. Forty PD patients and 46 controls were recruited to compare serum levels of iron, ferritin, transferrin, oxidative stress markers (superoxide dismutase (SOD), catalase (CAT), nitrosative stress marker (NOx), thiobarbituric acid reactive substances (TBARS), non-protein thiols (NPSH), advanced oxidation protein products (AOPP), ferric reducing ability of plasma (FRAP) and vitamin C) as well as inflammatory markers (NTPDases, ecto-5’-nucleotidase, adenosine deaminase (ADA), ischemic-modified albumin (IMA) and myeloperoxidase). Iron levels were lower in PD patients, whereas there was no difference in ferritin and transferrin. Oxidative stress (TBARS and AOPP) and inflammatory markers (NTPDases, IMA, and myeloperoxidase) were significantly higher in PD, while antioxidants FRAP, vitamin C, and non-protein thiols were significantly lower in PD. The enzymes SOD, CAT, and ecto-5’-nucleotidase were not different among the groups, although NOx and ADA levels were significantly higher in the controls. Our data corroborate the idea that ROS/RNS production and neuroinflammation may dysregulate iron homeostasis and collaborate to reduce the periphery levels of this ion, contributing to alterations observed in the pathophysiology of PD.

The association between the chronic use of non-steroidal anti- inflammatory drugs and oxidative and inflammatory markers in the elderly

OBJECTIVES

Investigate the association between the chronic or occasional use of nonsteroidal anti-inflammatory drugs (NSAIDs) and plasma levels of oxidative and inflammatory markers in elderly at the Family Health Strategy in Brazil.

METHODS

It was a cross-sectional study of data collected from random elderly volunteers. A questionnaire including sociodemographic, health and medicine use data was administered. The blood levels of FRAP (ferric reducing ability of plasma), AOPP (plasma advanced oxidation protein products), MDA (malondialdehyde) and insulin were measured.

RESULTS

The study sample comprised 758 elderly patients, of which 121 (15.96%) used NSAIDs. The mean age was 68.53 years and 68.41 for individuals who used NSAIDs occasionally and chronically, respectively. Gastric problems may be associated with the chronic or occasional use of NSAIDs (P = 0.042). Which indicates mean plasma levels of Insulin and HOMA-IR (Homeostasis Model Assessment Insulin Resistance) are increased in chronic use of NSAIDs and describes a statistical trend (P = 0.065) for the association of chronic NSAIDs use with the BMI (body mass index) of the subjects studied.

CONCLUSION

This study suggests that there is no association between the chronic or occasional use of NSAIDs and oxidative and inflammatory markers. It is known that NSAIDs have innumerable adverse effects, but they can have some benefits. So, additional studies are needed to clarify whether NSAIDs are associated with these markers and whether they are related with their real consequences.

Association between hypertriglyceridemia and protein oxidation and proinflammatory markers in normocholesterolemic and hypercholesterolemic individuals

BACKGROUND

Although hypercholesterolemia is a well-established risk factor for coronary heart disease, evidence suggests that increased triglyceride (TG) concentrations are also an independent risk factor. TG concentrations >150mg/dl are observed nearly twice as often in subjects with atherosclerosis. We assessed the association between hypertriglyceridemia and protein oxidation and proinflammatory markers in normocholesterolemic and hypercholesterolemic individuals.

METHODS

We included 127 volunteers enrolled in Cruz Alta, RS, Brazil. The patients were stratified based on total cholesterol and TG concentrations for analysis of associations with inflammation (high-sensitivity C-reactive protein - hs-CRP), endothelial dysfunction (nitric oxide - NOx) and oxidative stress (advanced oxidation protein products - AOPPs; ischemia-modified albumin - IMA). Correlations between variables were determined and multiple regression analysis was employed to investigate whether some variables correlate with TG concentrations.

RESULTS

Hypertriglyceridemia was related to oxidative stress and proinflammatory markers in individuals independent of total cholesterol concentrations. Moreover, the results indicate a stronger association of tested biomarkers with TG concentrations than with total cholesterol. The results indicate a positive correlation between oxidative stress and TG concentrations in the sera of hypercholesterolemia subjects. AOPPs and IMA concentrations were associated with the presence of hypertriglyceridemia in a manner that was independent of age, gender, hypertension and diabetes mellitus disease, smoking habits, sedentary lifestyle, BMI, waist circumference, LDL, HDL and total cholesterol concentrations.

CONCLUSIONS

We speculate that TG concentrations can reflect the enhancement of protein oxidation and proinflammation.

Serum levels of nitric oxide and protein oxidation in goats seropositive for Toxoplasma gondii and Neospora caninum

The aim of this study was to assess and analyze the levels of nitric oxide (NO) and advanced oxidation protein products (AOPP) in serum of goats naturally infected by Toxoplasma gondii, Neospora caninum, or concomitantly infected by these two parasites. Thus, it was measured NOx and AOPP levels in twenty (n=20) sera samples of goats seronegative for T. gondii and N. caninum [negative control group (A)]; while the positive groups were composed by sera of infected animals, twelve (n=12) seropositive for N. caninum [group B]; eighteen (n=18) positive for T. gondii [group C]; and thirteen (n=13) seropositive for N. caninum and T. gondii [group D]. As results, it was observed that animals seropositive for N. caninum and T. gondii (Groups B to D) showed higher serum levels of NOx (P<0.001; F=9.5), when compared with seronegative animals. Additionally, it was observed a positive correlation between NOx levels and antibodies titrations for N. caninum (P<0.01; r=0.68) and T. gondii (P<0.05; r=0.56). AOPP levels were increase in groups C and D (P>0.05). Interestingly, group B did not show increase in AOPP, what led us to hypothesize that the major protein damage is linked to T. gondii infection. Therefore, our results showed an increased in NOx levels, which was probably related to the immune response, since it is an important inflammatory mediator; and AOPP were increased in groups where there was seropositivity for T. gondii, but not for the group composed only by animals seropositive for N. caninum, allowing us to suggest higher protein damage in toxoplasmosis.

Ischemia-modified albumin and inflammatory biomarkers in patients with prostate cancer

BACKGROUND

Prostate cancer has become a public health problem in many countries and there is evidence which indicates that inflammation and oxidative stress play a key role in the pathogenesis of this disease. Thus, the aim of this study was to evaluate the concentrations of new biomarkers of oxidative stress, ischemia-modified albumin (IMA) and ferric reducing ability of plasma (FRAP), as well as the inflammatory markers in patients with prostate cancer.

METHODS

CRP, IMA, FRAP, fasting glucose, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, uric acid, creatinine, albumin, AST, ALT, ADA, total PSA (tPSA), free PSA, and proportion of free PSA (fPSA%) were measured in 25 patients with prostate cancer and in 30 healthy subjects.

RESULTS

tPSA, CRP, and IMA were significantly higher in patients with prostate cancer. In contrast, fPSA% and FRAP were significantly lower in these patients. However, no significant differences were observed when IMA values were adjusted for serum albumin. Significant correlations were also observed for tPSA and CRP (r = 0.5104, p < 0.001) and for fPSA% and CRP (r = -0.5059, p < 0.001).

CONCLUSIONS

We demonstrated that both inflammatory and oxidative processes are increased during prostate cancer and also that there is a reduction of antioxidant defenses in this pathology.

Effects of Campomanesia xanthocarpa on inflammatory processes, oxidative stress, endothelial dysfunction and lipid biomarkers in hypercholesterolemic individuals

In Brazil, the edible plant Campomanesia xanthocarpa Berg. (Myrtaceae), popularly known as "guavirova," has been studied in hypercholesterolemic individuals. The present work investigated the effects of C. xanthocarpa on inflammatory processes, oxidative stress, endothelial dysfunction and lipid biomarkers in hypercholesterolemic individuals. A total of 156 individuals were selected in a double-blind fashion and randomly divided into two groups in accordance with the intervals used in the criteria for hypercholesterolemia: individuals with total cholesterol (TC) levels between 200 and 240 mg/dL (undesirable level individuals - UL) and individuals with TC levels >240 mg/dL (hypercholesterolemic individuals - HL). Both groups had a control group (CG), which received placebo treatment, an encapsulated excipient group (lactose) and an experimental group that received 500 mg (EG 500), 750 mg (EG 750) or 1000 mg (EG 1000) of encapsulated C. xanthocarpa. The inflammatory processes (high-sensitivity C-reactive protein - hs-CRP), oxidative stress (advanced oxidation protein products-AOPPs; ischemia-modified albumin-IMA), endothelial dysfunction (nitric oxide - NOx) and biochemical (TC, triglycerides, high-density lipoprotein - HDL, low-density lipoproteins - LDL, and very low-density lipoprotein - VLDL) parameters were measured before and 90 days after the initiation of treatment. A significant decrease in TC and LDL levels was observed in HL individuals from the EG 500 group (reduction of 29 ± 3% and 41 ± 5% to levels before treatment) compared to the CG group individuals. A significant reduction in oxidative stress and inflammatory process components (reduction of 52 ± 11% in AOPPs, 32 ± 10% in IMA and 57 ± 7% in hs-CRP) and a significant increase in NOx (increase of 84 ± 27%) was observed in HL individuals in the EG 1000 group when compared to the CG group individuals. Treatment with encapsulated C. xanthocarpa reduced blood TC and LDL levels in hypercholesterolemic individuals. In addition to its effect on cholesterol levels, this plant reduced oxidative stress in hypercholesterolemic individuals and improved the levels of NOx.

Bixin and norbixin have opposite effects on glycemia, lipidemia, and oxidative stress in streptozotocin-induced diabetic rats

The present study investigated the effects of oral administration of annatto carotenoids (bixin (BIX) and norbixin (NBIX)) on glucose levels, lipid profiles, and oxidative stress parameters in streptozotocin (STZ)-induced diabetic rats. Animals were treated for 30 days in the following groups: nondiabetic control, diabetic vehicle, diabetic 10 mg/kg BIX, diabetic 100 mg/kg BIX, diabetic 10 mg/kg NBIX, diabetic 100 mg/kg NBIX, diabetic metformin, and diabetic insulin. Blood glucose, LDL cholesterol, and triglyceride levels were reduced in the diabetic rats treated with BIX. BIX treatment prevented protein oxidation and nitric oxide production and restored superoxide dismutase activity. NBIX treatment did not change most parameters assessed, and at the highest dose, it increased LDL cholesterol and triglycerides levels and showed prooxidant action (increased protein oxidation and nitric oxide levels). These findings suggested that BIX could have an antihyperglycemic effect, improve lipid profiles, and protect against damage induced by oxidative stress in the diabetic state. Because NBIX is a water-soluble analog of BIX, we propose that lipophilicity is crucial for the protective effect of annatto carotenoids against streptozotocin-induced diabetes.

Assessment of inflammatory and oxidative biomarkers in obesity and their associations with body mass index

The aim of this study was to evaluate the inflammatory and oxidative biomarkers' levels in obese subjects and their associations with body mass index (BMI), in order to investigate the role of these biomarkers in obesity. Fasting glucose, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, apolipoprotein A, apolipoprotein B, albumin, urinary albumin, creatinine, glomerular filtration rate, interleukin-6 (IL-6), nitrate/nitrite (NOx), and ischemia-modified albumin (IMA) were measured in 93 subjects divided according to different BMI. IL-6, urinary albumin, and IMA levels were significantly higher in obese subjects. However, the levels of NOx were significantly lower in this population. Significant correlations between BMI and IL-6 (r = 0.326, P = 0.002), NOx (r = -0.249, P = 0.021), urinary albumin (r = 0.270, P = 0.008), and IMA (r = 0.286, P = 0.005) were reported. We have shown an increase of IL-6, urinary albumin, and IMA combined with lower levels of NOx in obese patients and an association between of these biomarkers with BMI, suggesting a possible interplay of oxidative stress, inflammation, and endothelial dysfunction state in obesity.

Fructose-1,6-bisphosphate and N-acetylcysteine attenuate the formation of advanced oxidation protein products, a new class of inflammatory mediators, in vitro

The accumulation of advanced oxidation protein products (AOPP) has been linked to several pathological conditions. Previous studies have identified AOPP as a novel biomarker of oxidative damage to proteins and a novel class of mediator of inflammation. The aim of this study was to determine the effects of fructose-1,6-bisphosphate (FBP) and N-acetylcysteine (NAC) as well as the synergistic effect of both treatments on the formation of AOPP in vitro. For this purpose, we incubated the human serum albumin (HSA) with various hypochlorous acid (HOCl) concentrations to produce albumin-advanced oxidation protein products (HSA-AOPP). Both FBP and NAC were capable of inhibiting the formation of HOCl-induced AOPP in a concentration-dependent manner. The synergistic effect promoted by the association of these drugs showed to be more effective than when tested alone. Thus, both FBP and NAC may be good candidates to mitigate and neutralize pro-inflammatory and pro-oxidant effects of AOPP in several diseases.

Ischemia modified albumin and carbonyl protein as potential biomarkers of protein oxidation in hemodialysis

OBJECTIVE

The aim of this study was to evaluate the effect of HD on ischemia modified albumin (IMA) and protein carbonyl groups in order to investigate the role of IMA as a marker of protein oxidation.

DESIGN AND METHODS

This study was conducted with 23 chronic hemodialysis patients. The serum IMA levels and protein carbonyl groups were measured immediately before hemodialysis (pre-HD) and after the end of hemodialysis (post-HD).

RESULTS

IMA concentrations were significantly higher in post-HD than those of the pre-HD and carbonyl protein concentrations were higher in post-HD in comparison with pre-HD. A significant correlation was observed between IMA and carbonyl protein levels.

CONCLUSIONS

The increase of IMA levels and protein carbonyl groups post-HD could be attributed to the increase of oxidative stress associated with HD, and IMA appears to be an important biomarker for assessing protein oxidation after HD.