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.

Severity of Mitral Valve Stenosis　- Possible Relationships With Blood Oxidant Markers and Antioxidants.

BACKGROUND: This study examined whether the severity of mitral valve stenosis (MVS) is associated with oxidative stress (OS) markers in the blood, and other hematological and clinicodemographic parameters.Methods and Results: This prospective study was conducted between March and May 2022. Seventy-five patients with newly diagnosed MVS (25 mild, 25 moderate, 25 severe) were included. Mild, moderate, and severe MVS was defined as MV area >2, 1.5-2, and <1.5 cm2, respectively. Various OS markers and laboratory parameters were determined in venous blood samples. For predictive analyses, 2 different analyses were performed to detect patients with severe MVS and those with moderate or severe (moderate/severe) MVS. Age (P=0.388) and sex (P=0.372) distribution were similar in the 3 groups. Multiple logistic regression analysis revealed that a high white blood cell (WBC) count (P=0.023) and high malondialdehyde (P=0.010), superoxide dismutase (SOD; P=0.008), and advanced oxidation protein products (AOPP; P=0.007) levels were independently associated with severe MVS. A low platelet count (P=0.030) and high malondialdehyde (P=0.018), SOD (P=0.008), and AOPP (P=0.001) levels were independently associated with having moderate/severe MVS. The best discriminatory factors for severe MVS were SOD (cut-off >315.5 ng/mL) and glutathione (cut-off >4.7 µmol/L). CONCLUSIONS: MVS severity seems to be affected by oxidant markers (malondialdehyde and AOPP), antioxidant enzymes (SOD), and inflammation-related cells (WBC and platelets). Future studies are needed to examine these relationships in larger populations.

Pulsed Hyperoxia Acts on Plasmatic Advanced Glycation End Products and Advanced Oxidation Protein Products and Modulates Mitochondrial Biogenesis in Human Peripheral Blood Mononuclear Cells: A Pilot Study on the "Normobaric Oxygen Paradox".

The "normobaric oxygen paradox" (NOP) describes the response to the return to normoxia after a hyperoxic event, sensed by tissues as an oxygen shortage, up-regulating redox-sensitive transcription factors. We have previously characterized the time trend of oxygen-sensitive transcription factors in human PBMCs, in which the return to normoxia after 30% oxygen is sensed as a hypoxic trigger, characterized by hypoxia-induced factor (HIF-1) activation. On the contrary, 100% and 140% oxygen induce a shift toward an oxidative stress response, characterized by NRF2 and NF-kB activation in the first 24 h post exposure. Herein, we investigate whether this paradigm triggers Advanced Glycation End products (AGEs) and Advanced Oxidation Protein Products (AOPPs) as circulating biomarkers of oxidative stress. Secondly, we studied if mitochondrial biogenesis was involved to link the cellular response to oxidative stress in human PBMCs. Our results show that AGEs and AOPPs increase in a different manner according to oxygen dose. Mitochondrial levels of peroxiredoxin (PRX3) supported the cellular response to oxidative stress and increased at 24 h after mild hyperoxia, MH (30% O2), and high hyperoxia, HH (100% O2), while during very high hyperoxia, VHH (140% O2), the activation was significantly high only at 3 h after oxygen exposure. Mitochondrial biogenesis was activated through nuclear translocation of PGC-1α in all the experimental conditions. However, the consequent release of nuclear Mitochondrial Transcription Factor A (TFAM) was observed only after MH exposure. Conversely, HH and VHH are associated with a progressive loss of NOP response in the ability to induce TFAM expression despite a nuclear translocation of PGC-1α also occurring in these conditions. This study confirms that pulsed high oxygen treatment elicits specific cellular responses, according to its partial pressure and time of administration, and further emphasizes the importance of targeting the use of oxygen to activate specific effects on the whole organism.

Biochemical and Biophysical in Vitro Studies and Systematic Literature Review on the Antioxidant and Antiglycation Activities of Trazodone.

BACKGROUND/AIMS: Trazodone is a selective serotonin reuptake inhibitor; however, other mechanisms of the drug's anti-depressive properties have also been postulated. Hence, the aim of the study was to perform a systematic review and assess antiglycoxidative properties of trazodone in in vitro models. METHODS: Trazodone's scavenging and chelating properties were measured with spectrophotometric method. The impact of the drug on carbonyl/oxidative stress was marked in the bovine serum albumin (BSA) model where sugars (glucose, fructose, galactose, ribose) and aldehydes (glyoxal and methylglyoxal) were used as glycation agents. Aminoguanidine and N-acetylcysteine (NAC) were applied as reference glycation/free radical inhibitors. Glycation biomarkers (kynurenine, N-formylkynurenine, dityrosine as well as advanced glycation end products contents) were assessed spectrofluorometrically. Concentrations of oxidation parameters (total thiols (TTs), protein carbonyls (PCs) and also advanced oxidation protein products (AOPPs) levels) were determined spectrophotometrically. RESULTS: We demonstrated that trazodone poorly scavenged radicals (hydroxyl radical, nitric oxide, hydrogen peroxide and 2,2-diphenyl-1-picrylhydrazyl radical) and showed low ferrous ion chelating, unlike aminoguanidine and NAC. Sugars/aldehydes caused enhancement of glycation parameters, as well as a decrease of TTs and an increase of PCs and AOPPs levels compared to BSA incubated alone. Trazodone did not reduce oxidation parameters to the baseline (BSA) and significantly exacerbated glycation markers in comparison with both BSA and BSA+glycators. The content of glycation products was markedly lower in aminoguanidine and NAC than in trazodone. The molecular docking of trazodone to BSA revealed its very low affinity, which may indicate non-specific binding of trazodone, facilitating the attachment of glycation factors. CONCLUSION: According to our findings, it may be concluded that trazodone poorly counteracts oxidation and intensifies glycation in vitro. A possible mechanism for antiglycoxidative effect of trazodone in vivo may be the enhancement of the body's adaptive response, as indicated by the results of our systematic review.

Small extracellular vesicles-transported lncRNA TDRKH-AS1 derived from AOPPs-treated trophoblasts initiates endothelial cells pyroptosis through PDIA4/DDIT4 axis in preeclampsia.

BACKGROUND: Substantial studies have demonstrated that oxidative stress placenta and endothelial injury are considered to inextricably critical events in the pathogenesis of preeclampsia (PE). Systemic inflammatory response and endothelial dysfunction are induced by the circulating factors released from oxidative stress placentae. As a novel biomarker of oxidative stress, advanced oxidation protein products (AOPPs) levels are strongly correlated with PE characteristics. Nevertheless, the molecular mechanism underlying the effect of factors is still largely unknown. METHODS: With the exponential knowledge on the importance of placenta-derived extracellular vesicles (pEVs), we carried out lncRNA transcriptome profiling on small EVs (sEVs) secreted from AOPPs-treated trophoblast cells and identified upregulated lncRNA TDRKH-AS1 as a potentially causative factor for PE. We isolated and characterized sEVs from plasma and trophoblast cells by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and western blotting. The expression and correlation of lncRNA TDRKH-AS1 were evaluated using qRT-PCR in plasmatic sEVs and placentae from patients. Pregnant mice injected with TDRKH-AS1-riched trophoblast sEVs was performed to detect the TDRKH-AS1 function in vivo. To investigate the potential effect of sEVs-derived TDRKH-AS1 on endothelial function in vitro, transcriptome sequencing, scanning electron Microscopy (SEM), immunofluorescence, ELISA and western blotting were conducted in HUVECs. RNA pulldown, mass spectrometry, RNA immunoprecipitation (RIP), chromatin isolation by RNA purification (ChIRP) and coimmunoprecipitation (Co-IP) were used to reveal the latent mechanism of TDRKH-AS1 on endothelial injury. RESULTS: The expression level of TDRKH-AS1 was significantly increased in plasmatic sEVs and placentae from patients, and elevated TDRKH-AS1 in plasmatic sEVs was positively correlated with clinical severity of the patients. Moreover, pregnant mice injected with TDRKH-AS1-riched trophoblast sEVs exhibited a hallmark feature of PE with increased blood pressure and systemic inflammatory responses. Pyroptosis, an inflammatory form of programmed cell death, is involved in the development of PE. Indeed, our in vitro study indicated that sEVs-derived TDRKH-AS1 secreted from AOPPs-induced trophoblast elevated DDIT4 expression levels to trigger inflammatory response of pyroptosis in endothelial cells through interacting with PDIA4. CONCLUSIONS: Herein, results in the present study supported that TDRKH-AS1 in sEVs isolated from oxidative stress trophoblast may be implicated in the pathogenesis of PE via inducing pyroptosis and aggravating endothelial dysfunction.

Severe COVID-19 classified by simple covid risk index is associated with higher levels of advanced oxidation protein products and 8-hydroxy 2 deoxyguanosine.

SARS-CoV-2 has become one of the most important and challenging medical research topics in recent years. The presence of endothelial dysfunction, immune thrombosis, and oxidative stress contributes to complications and requires more extended hospitalisation of patients. In this article, we focused on analysing the impact of oxidative stress on the severity of COVID-19 infection. The study group consisted of 72 patients with laboratory-confirmed SARS-CoV enrolled. The patients were divided into moderate and severe diseases according to the SCRI (Simple Covid Risk Index, including lymphocyte/D-dimer ratio). Using the ELISA kit, we determined the level of AOPP and 8-OHdG. Patients with severe COVID-19 had higher levels of both AOPP (P < 0.05) and 8-OHdG (P < 0.05) compared to patients with moderate disease. Albumin levels were significantly lower (P < 0.001), although fibrinogen (P < 0.01), D-dimer (P < 0.001), and TF (P < 0.05) levels were higher in severe patients than in moderate course. AOPP/Alb was also higher among severe patients (P < 0.05). Our data suggest a potential role for AOPP and 8-OHdG in predicting the outcome of SARS-CoV-2 patients. Elevated AOPP levels were associated with increased Dimer-D, TF, and vWF activity levels.

Changes in salivary biomarkers of stress, inflammation, redox status, and muscle damage due to Streptococcus suis infection in pigs.

BACKGROUND: Streptococcus suis (S. suis) is a Gram-positive bacteria that infects pigs causing meningitis, arthritis, pneumonia, or endocarditis. This increases the mortality in pig farms deriving in severe economic losses. The use of saliva as a diagnostic fluid has various advantages compared to blood, especially in pigs. In this study, it was hypothesized that saliva could reflect changes in different biomarkers related to stress, inflammation, redox status, and muscle damage in pigs with S. suis infection and that changes in these biomarkers could be related to the severity of the disease. RESULTS: A total of 56 growing pigs from a farm were selected as infected pigs (n = 28) and healthy pigs (n = 28). Results showed increases in biomarkers related to stress (alpha-amylase and oxytocin), inflammation (haptoglobin, inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4), total protein, S100A8-A9 and S100A12), redox status (advanced oxidation protein producs (AOPP)) and muscle damage (creatine kinase (CK), CK-MB, troponin I, lactate, aspartate aminotransferase, and lactate dehydrogenase). An increase in adenosine deaminase (ADA), procalcitonin, and aldolase in infected animals were also observed, as previously described. The grade of severity of the disease indicated a significant positive correlation with total protein concentrations, aspartate aminotransferase, aldolase, and AOPP. CONCLUSIONS: This report revealed that S. suis infection caused variations in analytes related to stress, inflammation, redox status, and muscle damage in the saliva of pigs and these can be considered potential biomarkers for this disease.

Changes in biomarkers of redox status in serum and saliva of dogs with hypothyroidism.

BACKGROUND: Hypothyroidism is the most common endocrine disorder diagnosed in dogs, leading to deleterious effects on a dog's life quality. This study aims to evaluate changes in the redox status in canine hypothyroidism. For this purpose, a comprehensive panel of antioxidants and oxidants biomarkers were measured in serum and saliva of 23 dogs with hypothyroidism, 21 dogs with non-thyroidal illness, and 16 healthy dogs. Among the antioxidants, cupric reducing antioxidant capacity (CUPRAC), ferric reducing ability of plasma (FRAP), Trolox equivalent antioxidant capacity (TEAC), thiol, paraoxonase type 1 (PON-1) and glutathione peroxidase (GPx) were determined in serum and CUPRAC, ferric reducing ability of saliva (FRAS) and TEAC in saliva. The oxidant biomarkers included were total oxidant status (TOS), peroxide-activity (POX-Act), reactive oxygen-derived compounds (d-ROMs), advanced oxidation protein products (AOPP), and thiobarbituric acid reactive substances (TBARS) in serum and AOPP and TBARS in saliva. RESULTS: Results showed a significantly higher TEAC, PON-1, GPx, TOS, POX-Act, and d-ROMs, and a significantly lower AOPP in serum of dogs with hypothyroidism. Meanwhile, significantly lower FRAS and AOPP were observed in saliva of dogs with hypothyroidism. Once salivary concentrations were corrected based on their total protein concentrations, the only analyte showing significant changes was TBARS which was significantly higher in dogs with hypothyroidism. CONCLUSIONS: Our results show that dogs with hypothyroidism present alterations in the redox status in both serum and saliva. This study should be considered a preliminary study and further research addressing these changes should be made using larger populations.

P66Shc is increased in peripheral blood mononuclear cells of the patients with obstructive sleep apnea.

Objective: Obstructive sleep apnea (OSA) is characterized by nocturnal intermittent hypoxemia and linked to oxidative stress. Evidence demonstrated that p66Shc plays a key role in regulating oxidative stress. This study aimed to investigate the expression of p66Shc in peripheral blood mononuclear cells (PBMCs) of patients with OSA and the association with polysomnographic parameters. Methods: Fifty-four OSA subjects and 19 no OSA controls were enrolled in this study. All the subjects underwent standard polysomnography. P66Shc mRNA and protein levels in the PBMCs were detected by quantitative real-time polymerase chain reaction and western blotting. Plasma 3-nitrotyrosine (3-NT), oxidized low density lipoprotein (oxLDL), and advanced oxidation protein products (AOPP) were measured by ELISA method. Results: P66Shc mRNA and protein levels in PBMCs were significantly higher in OSA patients than in controls. P66Shc mRNA was positively correlated with plasma 3-NT, oxLDL, AOPP, hypopnea index (AHI), oxygen desaturation index (ODI), percentage of total sleep time with oxygen saturation (SaO2) below 90% (CT90), epworth sleepiness scale (ESS) and lymphocytes; negatively correlated with lowest SaO2 (LSaO2) and mean SaO2 (MSaO2). Further multivariate linear regression analysis showed that p66Shc mRNA levels were independently associated with AHI, MSaO2 and CT90. Conclusions: Oxidative stress regulator p66Shc may play a role in the pathophysiology of OSA and might serve as a potential biomarker for this disease.

Human protozoa infection and dysplasia in ulcerative colitis: a neglected aspect in a prominent disease.

The chance of getting colorectal cancer (CRC) is higher in people with chronic ulcerative colitis (UC). The impact of parasitic infections on UC is underappreciated. The purpose of this study was to look into the effect of intestinal protozoal infections on the dysplastic changes generated by UC. The research included 152 adult patients with histologically confirmed UC and 152 healthy controls. Fecal samples were examined for the presence of parasites and fecal calprotectin (FC). The enzyme-linked immunosorbent assay measured serum anti-p53 antibodies (p53Abs) and metallothioneins (MTs). The advanced oxidation protein products (AOPPs) and reduced glutathione (GSH) levels were measured by a spectrophotometric method in all subjects. Serum C-reactive protein (CRP) and IL-6 were also measured. In addition, histopathological and immunohistochemical investigations of intestinal tissue were done. Our results exhibited significant increases in FC and CRP, IL-6, AOPPs, MTs, and p53Abs in ulcerative colitis patients with parasitic infections compared to those without parasites. In contrast, GSH levels showed a significant decrease in the same group compared with other groups. Histopathological and immunohistochemical assessments of intestinal tissue signified severe inflammation and strong expression of PD-L1 in patients with parasitic infections compared to others without parasitic infections. Our research indicated a greater frequency of intestinal protozoa in UC patients with elevated inflammatory and dysplastic biomarker levels. This suggests that these parasites may be involved in the etiology of chronic UC and the associated carcinogenetic process. This is the first report of a link between parasitic infections and dysplastic alterations in UC patients.

The effect of aerobic exercise on oxidative stress in patients with chronic kidney disease: a systematic review and meta-analysis with trial sequential analysis.

PURPOSE: The purpose of this study was to investigate how aerobic exercise affects oxidative stress (OS) in patients with chronic kidney disease (CKD). METHODS: Retrieval dates range from the date the database was established to 19 July 2023, without languages being restricted. A meta-analysis and sensitivity analysis were conducted using RevMan 5.3 and Stata 16.0. RESULTS: The meta-analysis showed that, compared to usual activity or no exercise, aerobic exercise significantly reduced the oxidative markers malondialdehyde (MDA) (mean differences (MD) - 0.96 (95% CI -1.33, - 0.59); p < 0.00001), advanced oxidation protein product (AOPP) (MD - 3.49 (95% CI - 5.05, - 1.93); p < 0.00001), F2-isoprostanes (F2-iso) (MD - 11.02 (95% CI - 17.79, - 4.25); p = 0.001). Aerobic exercise also increased the antioxidant marker superoxide dismutase (SOD) in CKD patients (standardized mean differences (SMD) 1.30 (95% CI 0.56, 2.04); p = 0.0005). Subgroup analysis showed a significant increase in glutathione peroxidase (GPX) in patients aged ≥60 years (SMD 2.11 (95% CI 1.69, 2.54); p < 0.00001). The change in total antioxidant capacity (TAC) after aerobic exercise was insignificant in patients with CKD. The trial sequential analysis supported aerobic exercise's effectiveness in improving MDA, SOD, AOPP, and F2-iso in patients with CKD. CONCLUSION: The results of this review suggest that aerobic exercise improves OS indicators (MDA, SOD, AOPP, and F2-iso) in CKD patients compared to conventional treatment or no exercise and that the effects on GPX and TAC indicators need further confirmation. For better validation of benefits and exploration of the best aerobic exercise regimen to improve OS status with CKD, further studies with high methodological quality and large sample sizes are needed.

(Pro)Renin Receptor Decoy Peptide PRO20 Protects against Oxidative Renal Damage Induced by Advanced Oxidation Protein Products.

Chronic kidney disease (CKD) is associated with advanced oxidation protein products (AOPPs). A recent study has shown that AOPP-induced renal tubular injury is mediated by the (pro)renin receptor (PRR). However, it is unclear whether the PRR decoy inhibitor PRO20 can protect against renal damage related to AOPPs in vivo. In this study, we examined the role of the PRR in rats with AOPP-induced renal oxidative damage. Male SD rats were subjected to unilateral nephrectomy, and after a four-day recuperation period, they were randomly divided into four groups (n = 6/group) for four weeks: control (CTR), unmodified rat serum albumin (RSA, 50 mg/kg/day via tail-vein injection), AOPPs-RSA (50 mg/kg/day via tail-vein injection), and AOPPs-RSA + PRO20 (50 mg/kg/day via tail-vein injection + 500 µg/kg/day via subcutaneous injection) groups. PRO20 was administered 3 days before AOPPs-RSA injection. Renal histopathology evaluation was performed by periodic acid-Schiff (PAS) staining, and biochemical parameters related to renal injury and oxidative stress biomarkers were evaluated. The expression of related indicators was quantified by RT-qPCR and immunoblotting analysis. In the results, rats in the AOPPs-RSA group exhibited higher levels of albuminuria, inflammatory cell infiltration, and tubular dilation, along with upregulation of oxidative stress, profibrotic and proinflammatory factors, and elevation of AOPP levels. Meanwhile, in the PRO20 group, these were significantly reduced. Moreover, the levels of almost all components of the renin-angiotensin system (RAS) and Nox4-dependent H2O2 production in urine and the kidneys were elevated by AOPPs-RSA, while they were suppressed by PRO20. Furthermore, AOPPs-RSA rats showed elevated kidney expression of the PRR and soluble PRR (sPRR) and increased renal excretion of sPRR. In summary, these findings suggest that PRR inhibition may serve as a protective mechanism against AOPP-induced nephropathy by inhibiting the intrarenal RAS and Nox4-derived H2O2 mechanisms.

Serum redox markers in uncomplicated type 2 diabetes mellitus accompanied with abnormal iron levels.

OBJECTIVES: This study aimed at evaluating the serum redox status in type 2 diabetes mellitus (T2DM) accompanied with an imbalance in iron concentrations. METHODS: Diabetic patients were grouped according to serum iron levels [normal (DNFe), low (DLFe), and high (DHFe)], and their clinical and redox parameters [total sulfhydryl groups (tSH), uric acid (UA), and total bilirubin (tBILI) as non-enzymatic antioxidants, and malondialdehyde (MDA) and advanced oxidation products of proteins (AOPP) as markers of oxidative stress] were determined. RESULTS: Glucose and HbA1c levels in the T2DM patients did not differ in function of serum iron. T2DM was associated with reduced tSH levels. In the diabetic patients, tSH, UA, and tBILI negatively correlated with MDA, as well as HbA1c with UA. Accordingly, AOPP and MDA were higher in the diabetic groups compared to the controls. The reduced antioxidant capacity was particularly pronounced in the DLFe group, which was further characterized by lower levels of UA and tBILI compared to the other groups. Subsequently, the level of MDA in the DLFe group was higher compared to the DNFe and DHFe groups. The positive correlation between serum iron levels and the antioxidants UA and tBILI, in conjunction with the negative correlation between serum iron levels and the markers of oxidative stress in the diabetic patients, corroborated the indication that comparatively higher level of oxidative stress is present when T2DM coexists with decreased iron levels. CONCLUSIONS: T2DM-associated redox imbalance is characterized by a decrease in serum total sulfhydryl groups and low serum iron-associated reduction in uric acid and total bilirubin levels, accompanied by increased oxidative stress markers. The relatively noninvasive and simple determination of these parameters may be of considerable interest in monitoring the pathophysiological processes in T2DM patients, and may provide useful insights into the effects of potential therapeutic or nutritional interventions.

Plasma levels of soluble RAGE, AGEs and AOPPs at the early stage of amyotrophic lateral sclerosis: A preliminary study.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder with largely unknown pathogenesis and no effective cure. It is believed that several, not mutually exclusive mechanisms contribute to the pathogenesis and progression of this disease, including, among others, elevated oxidative stress, excitotoxicity, increased neuroinflammation, and protein aggregation. Receptor for advanced glycation end products (RAGE) is a part of immunoglobulin superfamily; it is believed to participate in ALS pathogenesis. OBJECTIVES: Our previous studies on ALS demonstrated that RAGE is likely one of the key players in ALS, acting on its own and in tandem with its oxidative stress and pro-inflammatory ligands, such as advanced glycation end products (AGEs) or advanced oxidation protein products (AOPPs). In this study, based on our previous results, we aimed to establish blood levels of soluble RAGE, AGE and AOPP in ALS patients. MATERIAL AND METHODS: Forty-six coded and anonymized surplus plasma samples from ALS patients and non-neurological control were used in the study. The plasma levels of RAGE, AGE and AOPP were measured using enzyme-linked immunosorbent assay (ELISA) commercially available kits. Statistical evaluation of data was performed using one-way non-parametric analysis of variance (ANOVA) with Kruskal-Wallis post hoc test. RESULTS: Our results revealed a decline in soluble RAGE level, concurrent with an increase in the levels of AGEs and AOPPs in blood samples from ALS patients, signifying a loss of neuroprotective form of RAGE and a simultaneous increase in AGE and AOPP production and uptake at the early stage of the disease. CONCLUSIONS: The results obtained from our study indicate that further longitudinal study of RAGE, AGE and AOPP levels would be beneficial, outlining the dynamics between RAGE and its ligand levels as the disease progresses, and making them valuable diagnostic tools and potential therapeutic targets.

Effect of green tea and nicotine on haematological and biochemical parameters and histopathology of bone marrow and spleen on albino rats.

We investigate the effects of green tea extract (GTE) on the attenuation of nicotine hematotoxicity, oxidative stress, inflammation and spleen and bone marrow structural lesions. Rats were treated by injecting nicotine (1,5mg/kg b.w. for 7 weeks) intraperitoneally and thereby supplementing GTE 2% orally to them. Haematological profiles, inflammation markers, neutrophil/lymphocyte (NLR), platelet/lymphocyte (PLR) and mean platelet volume (MPV/Plat) ratios- and erythrocyte sedimentation rate (ESR) were evaluated. Splenic levels of malondialdehyde (MDA), nitric oxide (NO), advanced protein oxidation products (AOPP) and catalase activity were measured. Femur bone and spleen were subjected to histological study. Nicotine-induced haematological abnormalities, a rise in the NLR and MPV/Plat ratios and ESR values with a drop in the PLR values compared to other experimental groups and leads to a significant increase in MDA, NO and AOPP levels-with a decrease in catalase activity compared to control groups. The bone marrow and spleen of nicotine exposed rats showed severe degenerative changes. GTE supplementation attenuates hematotoxicity, induce a decrease in the inflammation markers values, improved the levels of MDA, NO, AOPP and catalase activity and attenuate the adverse histological effects. GTE rich on polyphenols and flavonoids revealed by the in vitro study protects against the hazardous effects of nicotine.

Effect of Advanced Oxidation Protein Products (AOPPs) and aging on the osteoclast differentiation of Myeloid-Derived Suppressor Cells (MDSCs) and its preliminary mechanism.

To verify the osteoclast differentiation ability of MDSCs from mice of different ages and explore the effect of AOPPs on the osteoclast differentiation of bone marrow MDSCs. Bone marrow cells from C57BL/6 (a.k.a C57) mice of different ages were subjected to flow cytometry, and CD11b+Ly6C+Ly6G+ MDSCs were sorted out. After induction of osteoclast differentiation, these cells were subjected to tartrate-resistant acid phosphatase (TRAP) and F-actin. MDSCs from bone marrows of old mice were injected into the tibial medullary cavity of young mice. One week later, the bone marrows were subjected to histological examination, TRAP, and cell count. MDSCs from bone marrows of old mice were sorted for induction of osteoclast differentiation, intervened with reactive oxygen species (ROS) scavenger, inducible nitric oxide synthase (iNOS) inhibitor, and nitric oxide (NO) scavenger, and then subjected to TRAP. 8-weeks-old C57 mice were injected with the same concentrations of either AOPPs or mouse serum albumin (MSA). Four weeks later, MDSCs from bone marrows were sorted and subjected to induction of osteoclast differentiation, followed by IHC staining and TRAP. MDSCs of 8-weeks-old C57 mice were extracted and subjected to in vitro induction of osteoclast differentiation with different concentrations of AOPPs, followed by TRAP training. The number of MDSCs in the bone marrows of old mice was significantly higher than that in young mice. MDSCs from bone marrows of old mice differentiated into large multinucleated TRAP+ osteoclasts, which were significantly different from those in the middle-aged and young mice in terms of cell quantity and morphology. The actin rings formed in the differentiated osteoclasts from MDSCs of bone marrows were densely distributed in the whole field of view, which were significantly denser than those in the middle-aged and young mice. After injection of MDSCs of old mice, the number of TRAP + osteoclasts in the tibial medullary cavity of young mice was significantly increased. NO inhibitor can significantly inhibit the osteoclast differentiation capacity of MDSCs from bone marrows of old mice. In vivo treatment with AOPPs significantly increased the proportion of MDSCs in the bone marrow, which is up to 55.2%. After injection of AOPPs in 8-week-old mice and induction of osteoclast differentiation from the MDSCs, the ratios of CD11b+ and Gr1+ cells were significantly higher than that in the control and MSA groups but was not significantly different from that in the 15-month-old mice. Upon in vitro treatment with different concentrations of AOPPs, the MDSCs did not show any sign of osteoclast differentiation. MDSCs can directly undergo osteoclast differentiation, the capacity of which is stronger in MDSCs of bone marrows of old mice; the NO pathway is a potential mechanism underlying this phenomenon. In vivo but not in vitro AOPPs treatment can induce osteoclast differentiation of MDSCs, indicating there might be other factors in the body that can interact with AOPPs to induce osteoclast differentiation of MDSCs.

Advanced oxidation protein products upregulate ABCB1 expression and activity via HDAC2-Foxo3α-mediated signaling in vitro and in vivo.

The unpredictable pharmacokinetics of non-renal cleared drugs in chronic kidney disease (CKD) patients is associated with the activity of drug transporters. However, the mechanisms underlying regulation of drug transporters are yet to be established. In this study, we demonstrated the involvement of a HDAC2-Foxo3α pathway in advanced oxidation protein products (AOPPs)-induced ATP-binding cassette subfamily B member 1 (ABCB1) expression and activity. The correlation of AOPPs accumulation with concentration of cyclosporine in plasma was evaluated in 194 patients with transplantation. Molecular changes in acetylation of various histones and related regulatory molecules were examined in HepG2 cell cultures treated with AOPPs. Accumulation of AOPPs in serum in relation to molecular changes in HDAC2-Foxo3α in vivo were evaluated in 5/6 nephrectomy (5/6 nx) and oral adenine (Adenine) CKD rat models. Interestingly, the cyclosporine level was negatively correlated with AOPPs in plasma. In addition, AOPPs markedly suppressed the expression of histone deacetylase 2 (HDAC2), inducing ABCB1 expression and activity in vitro and in vivo. Importantly, AOPPs modulated phosphorylation of Foxo3α and the upstream Akt protein. Our findings indicate that AOPPs regulate the expression and activity of ABCB1 via reducing HDAC2 expression and activating Foxo3α-dependent signaling. The collective results support the utility of AOPPs as a potential target for drug and/or dosage adjustment in CKD patients. Targeting of AOPPs presents a novel approach to regulate non-renal clearance.

Effect of a Ketogenic Diet on Oxidative Posttranslational Protein Modifications and Brain Homogenate Denaturation in the Kindling Model of Epilepsy in Mice.

This study focused on the ketogenic diet (KD) effects on oxidative posttranslational protein modification (PPM) as presumptive factors implicated in epileptogenesis. A 28-day of KD treatment was performed. The corneal kindling model of epileptogenesis was used. Four groups of adult male ICR mice (25-30 g) were randomized in standard rodent chow (SRC) group, KD-treatment group; SRC + kindling group; KD + kindling group (n = 10 each). Advanced oxidation protein products (AOPP) and protein carbonyl contents of brain homogenates together with differential scanning calorimetry (DSC) were evaluated. Two exothermic transitions (Exo1 and Exo2) were explored after deconvolution of the thermograms. Factor analysis was applied. The protective effect of KD in the kindling model was demonstrated with both decreased seizure score and increased seizure latency. KD significantly decreased glucose and increased ketone bodies (KB) in blood. Despite its antiseizure effect, the KD increased the AOPP level and the brain proteome's exothermic transitions, suggestive for qualitative modifications. The ratio of the two exothermic peaks (Exo2/Exo1) of the thermograms from the KD vs. SRC treated group differed more than twice (3.7 vs. 1.6). Kindling introduced the opposite effect, changing this ratio to 2.7 for the KD + kindling group. Kindling significantly increased glucose and KB in the blood whereas decreased the BW under the SRC treatment. Kindling decreased carbonyl proteins in the brain irrespectively of the diet. Further evaluations are needed to assess the nature of correspondence of calorimetric images of the brain homogenates with PPM.

Level of advanced oxidation protein products is associated with subclinical atherosclerosis.

BACKGROUND: Oxidative stress is an important factor in the pathomechanism of atherosclerosis. Advanced oxidation protein products (AOPPs) are considered markers of oxidative stress. Thickening of the carotid intima-media layers indicates subclinical atherosclerosis and can be detected by carotid ultrasound. OBJECTIVE: Our aim was to examine the association between carotid intima-media thickness (CIMT) and the level of AOPPs. METHODS: Carotid duplex scans and measurements of AOPPs were performed on 476 participants of a cardiovascular population study. The presence of conventional cardiovascular risk factors was investigated with a questionnaire, physical examination, and laboratory tests. RESULTS: There was a positive correlation between maximum CIMT and the level of AOPPs only in the male population (r = 0.219, p = 0.033). Multivariate analysis has revealed that the association between AOPPs and mean or maximum CIMT was independent of cardiovascular risk factors (OR = 1.458, p = 0.004, and OR = 2.038, p < 0.001). CONCLUSIONS: Among males, the elevated level of AOPPs as a marker of oxidative stress may signal the existence of early atherosclerotic alterations.

Changes in salivary analytes in cows due to the in vitro presence of feed.

BACKGROUND: The effect in a sialochemistry profile of the presence of usually available feed in dairy cows was evaluated by an in vitro experiment. For this purpose, a pooled clean saliva from five healthy dairy cows was incubated five times with a standard feed based on a total mixed ration (F), wheat hay (H), and grass (G). The salivary panel was integrated by biomarkers of stress (cortisol -sCor-, salivary alpha-amylase -sAA-, butyrylcholinesterase -BChE-, total esterase -TEA-, and lipase -Lip-), immunity (adenosine deaminase -ADA-), oxidative status (Trolox equivalent antioxidant capacity -TEAC-, the ferric reducing ability of saliva -FRAS-, the cupric reducing antioxidant capacity -CUPRAC-, uric acid, and advanced oxidation protein products -AOPP-), and enzymes, proteins, and minerals of general metabolism and markers of liver, muscle, and renal damage (aspartate aminotransferase -AST-, alanine aminotransferase -ALP-, γ-glutamyl transferase -gGT-, lactate dehydrogenase -LDH-, creatine kinase -CK-, creatinine, urea, triglycerides, glucose, lactate, total protein, phosphorus, and total calcium). RESULTS: Most of the evaluated analytes showed a coefficient of variations (CV) higher than 15% and/or significant changes compared with the clean saliva when feed was present. Some analytes, such as the oxidative status biomarkers (CV > 80%), AST (CV > 60%), or glucose (CV > 100%), showed significant changes with all the feed types tested. Others showed significant differences only with certain types of feed, such as LDH with F (CV > 60%) or triglycerides with F (CV > 100%) and H (CV > 95%). However, sCor or gGT remained unchanged (CV < 15%, P > 0.05) in all the treatments. CONCLUSIONS: The presence of feed can produce changes in most of the analytes measured in cows' saliva, being of high importance to consider this factor when saliva is used as a sample to avoid errors in the interpretation of the results.