Oxidative Stress Conditions Research Articles

Investigating the association between blood oxidative stress markers and dementia in Egyptian elderly women

BackgroundThe predicted increase in the senior population will have a substantial impact on mental health and dementia development, emphasizing the need to study the biochemical components related to the pathogenesis of dementia. Oxidative stress is caused by an imbalance between the production of reactive oxygen species and the antioxidant balance of the body. The brain is particularly vulnerable to oxidative stress because of the relatively low levels of antioxidants in the brain, high levels of polyunsaturated fatty acids, and increased oxygen needs. The increase of reactive oxygen species leads to the accumulation of protein oxidation by-products which has a key role in dementia pathogenesis. The aim of the study is to investigate the link between oxidative stress and dementia in Egyptian older women and its possible effect on dementia severity and types. A case–control study was conducted involving 40 elderly women with dementia, and another 40 cognitively intact controls. All participants were subjected to a comprehensive geriatric evaluation, which included cognitive assessment, depression screening, and functional assessment. Blood levels of malondialdehyde (an oxidative stress marker), glutathione peroxidase enzyme and total antioxidant capacity (an antioxidant markers) were measured.ResultsMalondialdehyde’s blood level was significantly higher in dementia cases (p < 0.001), indicating a higher oxidative stress status in dementia cases. While blood levels of both glutathione peroxidase enzyme and total antioxidant capacity were significantly lower in dementia cases (p < 0.001), indicating a lower antioxidant activity in dementia cases. We found that glutathione peroxidase enzyme at a cutoff point ≤ 122 mu/ml, total antioxidant capacity at a cutoff point ≤ 39.1 mm/l, and malondialdehyde at a cutoff point > 95 nmol/ml had perfect diagnostic value for identifying patients with dementia.ConclusionOxidative stress showed a significant role in the pathogenesis of dementia, with the presence of higher levels of oxidative damage by-products and lower levels of antioxidant status. So, the role of oxidative stress in dementia should not be neglected, and more effort should be directed to prevent unnecessary exposure to oxidative stress in older adults to contribute towards dementia prevention.

Metformin-induced oxidative stress inhibits LNCaP prostate cancer cell survival.

Preclinical and clinical studies over the past several decades have indicated the potential value of metformin, a widely utilized treatment for Type 2 diabetes, in prostate cancer therapy. Notably, these studies demonstrated metformin's pleiotropic effects on several molecular and metabolic pathways, such as androgen signaling, cell cycle, and cellular bioenergetics. In this study we investigated the role of metformin in regulating intracellular redox status and cell survival in LNCaP prostate cancer cells. The cytotoxic effects of metformin with or without the presence of SBI0206965 (AMPK inhibitor) on LNCaP cells were determined using MTT and trypan blue exclusion assays. Seahorse XP extracellular analysis, Liquid Chromatography/ Mass Spectrophotometry (LC/MS), and 2,7- and Dichlorofluoresin diacetate (DCFDA) assay were used to assess the effects of metformin on cellular bioenergetics, redox status, and redox-related metabolites. mRNA expression and protein concentration of redox-related enzymes were measured using Real Time-qPCR and ELISA assay, respectively. Independently of AMP-activated protein kinase, metformin exhibited a dose- and time-dependent inhibition of LNCaP cell survival, a response mitigated by glutathione or N-acetylcysteine (ROS scavengers) treatment. Notably, these findings were concomitant with a decline in ATP levels and the inhibition of oxidative phosphorylation. The results further indicated metformin's induction of reactive oxygen species, which significantly decreased glutathione levels and the ratio of reduced to oxidized glutathione, as well as the transsulfuration metabolite, cystathionine. Consistent with an induction of oxidative stress condition, metformin increased mRNA levels of the master redox transcription factor Nrf-2 (nuclear factor erythroid-derived 2-like), as well as transsulfuration enzymes cystathionine beta-synthase and cystathionase and GSH synthesis enzymes γ-glutamylcysteine synthetase and glutathione synthetase. Our findings highlight multiple mechanisms by which metformin-induced formation of reactive oxygen species may contribute to its efficacy in prostate cancer treatment, including promotion of oxidative stress, Nrf2 activation, and modulation of redox-related pathways, leading to its anti-survival action.

Exogenous Nucleotides Ameliorate Insulin Resistance Induced by Palmitic Acid in HepG2 Cells through the IRS-1/AKT/FOXO1 Pathways.

Nucleotides (NTs) act as pivotal regulatory factors in numerous biological processes, playing indispensable roles in growth, development, and metabolism across organisms. This study delves into the effects of exogenous NTs on hepatic insulin resistance using palmitic-acid-induced HepG2 cells, administering interventions at three distinct dosage levels of exogenous NTs. The findings underscore that exogenous NT intervention augments glucose consumption in HepG2 cells, modulates the expression of glycogen-synthesis-related enzymes (glycogen synthase kinase 3β and glycogen synthase), and influences glycogen content. Additionally, it governs the expression levels of hepatic enzymes (hexokinase, phosphoenolpyruvate carboxykinase, and glucose-6-phosphatase). Moreover, exogenous NT intervention orchestrates insulin signaling pathway (insulin receptor substrate-1, protein kinase B, and forkhead box protein O1) and AMP-activated protein kinase (AMPK) activity in HepG2 cells. Furthermore, exogenous NT intervention fine-tunes the expression levels of oxidative stress-related markers (malondialdehyde, glutathione peroxidase, and NADPH oxidase 4) and the expression of inflammation-related nuclear transcription factor (NF-κB). Lastly, exogenous NT intervention regulates the expression levels of glucose transporter proteins (GLUTs). Consequently, exogenous NTs ameliorate insulin resistance in HepG2 cells by modulating the IRS-1/AKT/FOXO1 pathways and regulate glucose consumption, glycogen content, insulin signaling pathways, AMPK activity, oxidative stress, and inflammatory status.

The relationship between endothelial-dependent flow-mediated dilation and diastolic function in type 2 diabetes

AimsDiastolic dysfunction represents the earliest and most common manifestation of diabetic cardiomyopathy. Nitric oxide (NO), a potent vasodilator and anti-inflammatory mediator released from the subendocardial and coronary endothelium, favors left ventricular distensibility and relaxation. In type 2 diabetes (T2D), the NO bioavailability is reduced due to the oxidative stress and inflammatory state of the endothelium, because of chronic hyperglycemia. The aim of the present research is to evaluate the relationship between endothelial function and diastolic function in subjects with T2D.MethodSubjects with T2D and age and sex-matched healthy controls were consecutively recruited. All participants underwent flow-mediated dilation (FMD) to assess endothelial function, and echocardiography to evaluate diastolic function.ResultsThirty-five patients (6 women, 29 men) and 35 healthy controls were included in the final analysis. FMD was significantly lower in T2D than controls (4.4 ± 3.4 vs. 8.5 ± 4.3%, p = 0.001). T2D presented different abnormalities in diastolic function compared to controls: lower E/A (early to late diastolic transmitral flow velocity), lower septal and lateral e′ (early diastolic myocardial tissue velocity at septum and lateral wall), and higher E/e′ (surrogate of filling pressure). In subjects with T2D, we observed a significant correlation between FMD and E/e′ (r = −0.63, p = 0.001), lateral e′ (r = 0.44, p = 0.03), and septal e′ (r = 0.39, p = 0.05).ConclusionsOur observational study demonstrated a link between FMD and diastolic dysfunction in subjects with type 2 diabetes.

Moderate to advanced periodontitis contributes to increased oxidative stress in cats: a case-control study

BackgroundPeriodontal diseases are the most frequently diagnosed problem in cats. It has been well-established that periodontal diseases could not only cause various oral health issues but could also contribute to systemic diseases. Oxidative stress is a possible link between systemic diseases and periodontitis. Our study aimed to illustrate the influence of periodontitis on oxidative stress development in cats. Furthermore, the changes in the bacterial flora of the gums were investigated.MethodsBased on the clinical and laboratory examinations, fifty cats were divided into two groups normal (n = 25) and moderate to advanced periodontitis (n = 25). Serum total antioxidant capacity (TAC), total oxidant status (TOS), reduced (GSH) and oxidized glutathione (GSSG) were measured. In addition, samples were taken from the subgingival plaques of all cats for bacterial culture.ResultsSerum TOS, GSSG, GSSG to GSH ratio, and oxidative stress index (OSI), calculated as the ratio of TOS to TAC in cats with periodontal disease were significantly higher, and TAC was significantly lower (p < 0.05) compared with controls. The results of bacterial culture indicated that the number of isolated bacterial colonies is higher in patients than in the control group. Additionally, the analysis of these data showed a positive association between periodontal index and oxidative stress.ConclusionsOur results revealed that periodontitis in cats is related to a main oxidative stress. Furthermore, oxidant factors such as TOS and OSI, compared to antioxidant factors, may better indicate the presence of oxidative stress conditions in patients with periodontitis.

Moderate-intensity Exercise Alleviates Rat's Systemic Inflammation Induced by Repeated Exposure to Lipopolysaccharide.

The protective impacts of physical activity against inflammatory and oxidative stress conditions have been demonstrated. In this study, the impacts of moderate-intensity exercise on oxidative stress-associated factors and proinflammatory cytokines levels as well as the count of white blood cells (WBC) were assessed in a lipopolysaccharide (LPS)-triggered model of inflammation. Wistar rats were randomized into these groups (8 rats in each): (1) control; (2) LPS; (3) moderate exercise (EX); and (4) moderate exercise + LPS (EX+LPS). Exercise groups were trained for 8 weeks (30 min, 6 days/week) at 15 m/min speed. During the final week of the experiment, 1 mg/kg/day of intraperitoneal LPS was administered for 5 days. On day 56, from the rats' hearts, peripheral blood was taken for biochemical evaluation. LPS enhanced serum levels of C-reactive protein (CRP), interleukin (IL)- 1β, tumor necrosis factor-α (TNF-α), metabolites of nitric oxide, and malondialdehyde (MDA), as well as the counts of total WBC, monocytes, neutrophils, and eosinophils, but decreased serum levels of thiol as well as superoxide dismutase (SOD) and catalase (CAT) activity versus the control rats. Moderate exercise reduced the levels of thiol, CAT, and SOD, but increased TNF-α level, and total WBC, neutrophils, eosinophils, and monocytes counts versus the control group. In the EX+LPS group, moderate exercise decreased cell counts and diminished MDA, TNF-α, IL-1β, and CRP levels, while increasing thiol level, CAT, and SOD versus the LPS group. In our study, exercise preconditioning reduced inflammation induced by LPS by ameliorating inflammatory cytokine levels, WBC counts, and oxidative damage, while improving antioxidant defenses.

Association between oxidative balance score, systemic inflammatory response index, and cardiovascular disease risk: a cross-sectional analysis based on NHANES 2007-2018 data.

There is limited research on the relationship between Systemic Oxidative Stress (SOS) status and inflammatory indices. Adding onto existing literature, this study aimed to examine the association between dietary Oxidative Balance Score (OBS) and lifestyle OBS (which make up the overall OBS), and Cardiovascular Disease (CVD) prevalence at different Systemic Immune Inflammation Index (SII) and Systemic Inflammatory Response Index (SIRI) levels. This study involved 9,451 subjects selected from the National Health and Nutrition Examination Survey (NHANES) 2007-2018. The OBS comprised 20 dietary and lifestyle factors. Statistical methods included Weighted Linear Regression Analysis (WLRA), Logistic Regression Analysis (LRA), Sensitivity Analysis (SA), and Restricted Cubic Spline (RCS) analysis. The multivariate WLRA revealed that OBS was significantly negatively correlated with both SII (β = -5.36, p < 0.001) and SIRI (β = -0.013, p < 0.001) levels. In SA, removing any single OBS component had no significant effect on the WLRA results of SII and SIRI. Further subgroup analyses revealed that OBS was more impactful in lowering SII in women than in men. Additionally, OBS was more significantly negatively correlated with SII and SIRI in the low-age group than in the high-age group. Moreover, RCS analysis confirmed this linear relationship. Compared to dietary OBS, lifestyle OBS exerted a more significant effect on Coronary Artery Disease (CAD) (OR: 0.794, p = 0.002), hypertension (OR: 0.738, p < 0.001), Congestive Heart Failure (CHF) (OR: 0.736, p = 0.005), Myocardial Infarction (MI) (OR: 0.785, p = 0.002), and stroke (OR: 0.807, p = 0.029) prevalence. Furthermore, SIRI exhibited a significant interaction in the relationship between overall OBS, dietary OBS, and CHF (P for interaction < 0.001). On the other hand, SII had a significant interaction in the relationship between overall OBS, dietary OBS, and MI (P for interaction < 0.05). OBS, including lifestyle and dietary OBS, were significantly negatively associated with SII and SIRI. Higher lifestyle OBS was associated with reduced risks of CAD, hypertension, CHF, MI, and stroke.

Musa basjoo Sieb polysaccharide improves inflammation in RAW264.7 cells and zebrafish colitis

Musa basjoo Sieb polysaccharide (MBSP) is the active ingredient of Musa basjoo Sieb. The purpose of this study was to preliminarily characterize the structural properties of MBSP, and to explore its ameliorating effect LPS-induced macrophage RAW264.7 inflammation and its therapeutic effect on DSS-induced zebrafish colitis. The data indicated that the average molecular weight of MBSP was 393.4 kDa, which was an acidic heteropolysaccharide composed of seven monosaccharides. In the LPS-induced macrophage RAW264.7 inflammation model, we found that MBSP significantly reduced the level of inflammatory mediators (p < 0.001). The release of NO, IL-6, and TNF-α was reduced by 48.21%, 65.45%, and 86.49%, respectively. And MBSP modulated intracellular ROS levels. This might be related to the activation of NF-κB/MAPK signaling pathway by MBSP. Additionally, MBSP significantly improved the oxidative stress status of UC zebrafish. SOD, CAT, GSH-Px were increased by 50.58%, 39.07% and 65.86%, and MDA, MPO were decreased by 26.00% and 50.98%, respectively (p < 0.001). Meanwhile, MBSP was also found to be effective in improving UC by activating the TLR4/NF-κB/MAPK signaling pathway in vivo. In conclusion, the present study characterized the structural properties of MBSP from various aspects, confirmed the anti-inflammatory effect of MBSP in vitro, and further verified the in vivo anti-inflammatory activity of MBSP using UC zebrafish as an animal model. The results of this study provide a reference for the development and application of MBSP in the field of treating inflammatory diseases.

Nutraceutical Features of the Phycobiliprotein C-Phycocyanin: Evidence from Arthrospira platensis (Spirulina).

Arthrospira platensis, commonly known as Spirulina, is a photosynthetic filamentous cyanobacterium (blue-green microalga) that has been utilized as a food source since ancient times. More recently, it has gained significant popularity as a dietary supplement due to its rich content of micro- and macro-nutrients. Of particular interest is a water soluble phycobiliprotein derived from Spirulina known as phycocyanin C (C-PC), which stands out as the most abundant protein in this cyanobacterium. C-PC is a fluorescent protein, with its chromophore represented by the tetrapyrrole molecule phycocyanobilin B (PCB-B). While C-PC is commonly employed in food for its coloring properties, it also serves as the molecular basis for numerous nutraceutical features associated with Spirulina. Indeed, the comprehensive C-PC, and to some extent, the isolated PCB-B, has been linked to various health-promoting effects. These benefits encompass conditions triggered by oxidative stress, inflammation, and other pathological conditions. The present review focuses on the bio-pharmacological properties of these molecules, positioning them as promising agents for potential new applications in the expanding nutraceutical market.

Innovative Molecularly Imprinted Electrochemical Sensor for Selective Nanomolar Detection of the Anti-COVID-19 Medication Molnupiravir

For the first time, a green ecofriendly approach is applied, to develop a molecularly imprinted polymer (MIP) electrochemical for the assay of the oral anti-viral molnupiravir (MLN) in various matrices as confirmed by referring to analytical eco-scale, green analytical procedure index (GAPI), Raynie and Driver, analytical greenness metric (AGREE), and national environmental index (NEMI). AuNPs were chronoamperometry deposited on the glassy carbon electrode surface (GCE) using 0.01 gm ml−1 gold solution (HAuCl4.3H2O) in 0.5 M H2SO4 at a constant potential of −0.4 V for 60 s. Then, the MIP was created by electropolymerizing OPDA on the surface of AuNPs GCE using cyclic voltammetry in the potential range between −0.5 and +1 V for 15 cycles (scan rate: 50 mV.s−1). To optimize the sensor’s performance, factors such as number of electropolymerization cycles, template: monomer ratio, binding and rebinding time, pH of rebinding buffer, extraction solvent, deposition time of Au nanoparticles, order of deposition on the electrode; surface, as well as differential pulse voltammetry parameters including accumulation potential and time, and potential step, were all investigated. The detection limit was set at 0.00098 ng ml−1 (3 × 10−12M) and the linearity range of MLN was between 0.033 ng ml−1 and 164 ng ml−1 (1 × 10−10–5 × 10−7 M). The MIP sensor was employed for MLN determination in its pharmaceutical product (capsules), spiked human plasma, and human urine samples with mean recovery % ± mean relative standard deviation (RSD) (99.82% ± 0.53), (99.88% ± 0.62), and (97.90% ± 0.70), respectively. The investigated sensor provided good reproducibility, repeatability, and durability. Acceptable selectivity regarding MLN when mixed with structurally comparable compounds was proved with mean recovery % ± mean RSD (97.10% ± 0.03). Additionally, when molnupiravir was exposed to oxidative, hydrolytic, and thermal stress conditions, good results in stability-indicating studies served as an indicator of sensor selectivity. The developed electrode is coupled with a portable potentiostat, making it a promising point-of-care diagnostic platform for on-site measurements.

Interplay between mistranslation and oxidative stress in Escherichia coli.

Mistakes in translation are mostly associated with toxic effects in the cell due to the production of functionally aberrant and misfolded proteins. However, under certain circumstances mistranslation can have beneficial effects and enable cells to preadapt to other stress conditions. Mistranslation may be caused by mistakes made by aminoacyl-tRNA synthetases, essential enzymes that link amino acids to cognate tRNAs. There is an Escherichia coli strain expressing isoleucyl-tRNA synthetase mutant variant with inactivated editing domain which produces mistranslated proteomes where valine (Val) and norvaline (Nva) are misincorporated into proteins instead of isoleucine. We compared this strain with the wild-type to determine the effects of such mistranslation on bacterial growth in oxidative stress conditions. When the cells were pre-incubated with 0.75 mmol/L Nva or 1.5 mmol/L Val or Nva and exposed to hydrogen peroxide, no beneficial effect of mistranslation was observed. However, when the editing-deficient strain was cultivated in medium supplemented with 0.75 mmol/L Val up to the early or mid-exponential phase of growth and then exposed to oxidative stress, it slightly outgrew the wild-type grown in the same conditions. Our results therefore show a modest adaptive effect of isoleucine mistranslation on bacterial growth in oxidative stress, but only in specific conditions. This points to a delicate balance between deleterious and beneficial effects of mistranslation.

Combined analysis of the effects of hypoxia and oxidative stress on DNA methylation and the transcriptome in HTR-8/SVneo trophoblast cells.

The alterations in DNA methylation and transcriptome in trophoblast cells under conditions of low oxygen and oxidative stress have major implications for pregnancy-related disorders. However, the exact mechanism is still not fully understood. In this study, we established models of hypoxia (H group) and oxidative stress (HR group) using HTR-8/SVneo trophoblast cells and performed combined analysis of genome-wide DNA methylation changes using reduced representation bisulphite sequencing and transcriptome expression changes using RNA sequencing. Our findings revealed that the H group exhibited a higher number of differentially methylated genes and differentially expressed genes than the HR group. In the H group, only 0.90% of all differentially expressed genes displayed simultaneous changes in DNA methylation and transcriptome expression. After the threshold was expanded, this number increased to 6.29% in the HR group. Notably, both the H group and HR group exhibited concurrent alterations in DNA methylation and transcriptome expression within Axon guidance and MAPK signalling pathway. Among the top 25 differentially methylated KEGG pathways in the promoter region, 11 pathways were commonly enriched in H group and HR group, accounting for 44.00%. Among the top 25 KEGG pathways in transcriptome with significant differences between the H group and HR group, 10 pathways were consistent, accounting for 40.00%. By integrating our previous data on DNA methylation from preeclamptic placental tissues, we identified that the ANKRD37 and PFKFB3 genes may contribute to the pathogenesis of preeclampsia through DNA methylation-mediated transcriptome expression under hypoxic conditions.

Liver epigenomic signature associated with chronic oxidative stress in a mouse model of glutathione deficiency

Oxidative stress is intimately involved in the pathogenesis of fatty liver disease (FLD). A major factor contributing to oxidative stress is the depletion of the ubiquitous antioxidant glutathione (GSH). Unexpectedly, chronic GSH deficiency renders glutamate-cysteine ligase modifier subunit (Gclm)-null mice protected from fatty liver injuries. Epigenetic regulation serves as an important cellular mechanism in modulating gene expression and disease outcome in FLD, although it is not well understood how systemic redox imbalance modifies the liver epigenome. In the current study, utilizing the Gclm-null mouse model, we aimed to elucidate redox-associated epigenomic changes and their implications in liver stress response. We performed high-throughput array-based DNA methylation profiling (MeDIP array) in 22,327 gene promoter regions (from −1300 bp to +500 bp of the Transcription Start Sites) in the liver and peripheral blood cells. Results from the MeDIP array demonstrate that, although global methylation enrichment in gene promoters did not change, low GSH resulted in prevalent demethylation at the individual promoter level. Such an effect likely attributed to a declined availability of the methyl donor S-adenosyl methionine (SAM) in Gclm-null liver. Functional enrichment analysis of liver target genes is suggestive of a potential role of epigenetic mechanisms in promoting cellular survival and lipid homeostasis in Gclm-null liver. In comparison with the liver tissue, MeDIP array in peripheral blood cells revealed a panel of 19 gene promoters that are candidate circulating biomarkers for hepatic epigenomic changes associated with chronic GSH deficiency. Collectively, our results provided new insights into the in vivo interplay between liver redox state and DNA methylation status. The current study laid the groundwork for future epigenetic/epigenomic investigations in experimental settings or human populations under conditions of liver oxidative stress induced by environmental or dietary challenges.

Antioxidative and Anti-inflammatory Effects of Plant-derived Hypoglycemic Medicines: An In vivo/In vitro Systematic Review.

The activation of oxidative stress and inflammatory conditions has been associated with acceleration in diabetes (DM) onset and complications. Despite various anti-DM medications, there is a growing trend to discover inexpensive and effective treatments with low adverse effects from plants as one of the promising sources for drug development. This study aimed to systematically investigate the simultaneous anti-inflammatory and antioxidant effects of plant-derived hypoglycemic medicines in diabetic experimental models. The search terms consisted of "diabetes", "herbal medicine", "antioxidant", "Inflammatory biomarker", and their equivalents among PubMed, Scopus, Web of Science, and Cochrane Library databases up to 17 August 2021. Throughout the search of databases, 201 eligible experimental studies were recorded. The results showed that the most commonly assessed inflammatory and oxidative stress biomarkers were tumor necrosis factor (TNF)-α, interleukin (IL) 6, IL-1β, IL-10, malondialdehyde (MDA), and nitric oxide (NO). The activity of antioxidant enzymes, including superoxide dismutase (SOD), glutathione (GSH), and catalase (CAT) were assessed in the present review. Among herbal treatments, Trigonella foenum-graecum L., Centella asiatica (L.) Urb., Vitis vinifera L., and Moringa oleifera Lam. were most commonly used for diabetic complications. Due to the dispersion of the treatments, meta-analysis was not applicable. Our findings showed that the application of different plant-derived hypoglycemic treatments in animal models improved diabetes and its complications, as well as modulated concomitant inflammatory and oxidative stress biomarkers. These findings suggest that plant-based antidiabetic medicines and food supplements have the potential to manage diabetes and its complications.

Development and validation of stability-indicating assay method and identification of force degradation products of glucagon-like peptide-1 synthetic analog Exenatide using liquid chromatography coupled with Orbitrap mass spectrometer.

Exenatide is a synthetic glucagon-like peptide 1 analog, widely used in the management of type 2 diabetes mellitus. The stability of pharmaceutical products is significantly impacted by various environmental stress conditions. The present study reports the development of a validated reverse-phase high-performance liquid chromatography (RP-HPLC) stability-indicating method for the identification of force degradation products (DPs) of synthetic glucagon-like peptide-1 analog Exenatide using UHPLC-Orbitrap fusionTM mass spectrometer. Force degradation studies were performed by subjecting Exenatide to various stress conditions, such as hydrolytic, oxidative, photolytic and thermal to investigate the stability indicating ability of the method. Significant degradation was observed during acidic, oxidative, photolytic and thermal stress conditions. Exenatide and its major DPs identification and characterization were demonstrated by employing LC-HRMS and MS/MS method. In total, five major stress DPs were characterized, and their fragmentation pathway was proposed using MS/MS studies. Finally, the proposed RP-HPLC method was validated as per ICH guidance.

A novel polysaccharide of Undaria pinnatifida: Structural characterization, carboxymethylation and hypoglycemic activity in vivo

A new polysaccharide (UPP) was isolated and purified from Undaria pinnatifida with a low molecular weight of 8.34 kDa. The UPP was modified to obtain carboxymethylated polysaccharide (CM-UPP). UPP and CM-UPP were characterized by FT-IR, Ion chromatography, Congo red, DSC, SEM and NMR, and their hypoglycemic activity in vivo was investigated using the STZ-induced diabetes mice model. UPP mainly contained Ara, Gal, Glc and Man at a molar ratio of 0.18: 0.13: 2.06: 1, and CM-UPP added two alduronic acids including GalA and GlcA. CM-UPP had been prepared successfully and the carboxymethylation reaction might occur partially at the C-2 and C-4 position. There were no triple helix structures in both UPP and CM-UPP. In vivo hypoglycemic activity studies showed that both UPP and CM-UPP could alleviate symptoms of high blood glucose, improve blood lipid level, oxidative stress state and liver glycolytic enzyme activity in diabetic mice. Under the same dose, CM-UPP showed a more significant effect than UPP. These results indicated that carboxymethylation was an effective way to enhance the hypoglycemic activitiy of polysaccharide. UPP and CM-UPP could be potential therapeutic agents of T2DM.

Ameliorative Effect of Pigeon Pea Leaves and Ginger Extract on Oxidative Stress Condition in Kidney and Liver of Experimental Diabetic Rats

Ameliorative Effect of Pigeon Pea Leaves and Ginger Extract on Oxidative Stress Condition in Kidney and Liver of Experimental Diabetic Rats

Characterization of Therapeutic Antibody Charge Heterogeneity Under Stress Conditions by Microfluidic Capillary Electrophoresis Coupled with Mass Spectrometry

Therapeutic antibodies are a major class of biopharmaceutics that are applied in disease treatment because of their many advantages, including high specificity and high affinity to molecular targets. Between their production and administration, therapeutic antibodies are exposed to multiple stress conditions. Forced degradation and stress stability studies are conducted to simulate the risk of degradation and the effects of these stresses, thereby enhancing understanding of the drug product to support strategies to mitigate the impact from stressed conditions. These types of studies are also routinely conducted to evaluate product comparability when major process changes are implemented during the production. Charge variant analysis helps understand the changes in the electrostatic environment of biotherapeutics and can uncover underlying molecular level alterations associated with charge variants. Herein, we used ZipChip native capillary electrophoresis-mass spectrometry (nCE-MS) to elucidate the changes in charge variant profiles at the molecular level. In two case studies under thermal stress conditions, we observed that charge variants arose from both post-translational modifications (including deamidation, oxidation, and pyroglutamate formation) and sequence truncations at the hinge regions. Under oxidative stress conditions, oxidation was found to be the major contributor to the changes in the charge variant profiles. Under pH stress conditions, the changes in the charge variant profile were due to increased levels of deamidation, oxidation, and pyroglutamate formation. ZipChip nCE-MS analysis enables identification of charge variant species under various stress conditions, thus supporting process and formulation development of biotherapeutics.

#2432 DNA damage analysis with oxidative stress index in patients developing contrast nephropathy after coronary angiography

Abstract Background and Aims Contrast Nephropathy (KN) is acute kidney injury that occurs after exposure to contrast material. Advanced age, chronic kidney disease, heart failure, anemia, hypertension, diabetes mellitus, and hyperuricemia have been reported in the literature to increase the risk of KN development. In addition, oxygen radicals have an important place in the pathogenesis of contrast nephropathy development. Specific biomarkers are used in clinics to determine oxidative stress and antioxidant status. In particular, measurement of total antioxidant status (TAS) and total oxidant status (TOS) can provide useful information about an individual's overall serum antioxidative status. The ratio of TOS to TAS level gives the oxidative stress index (OSI). One of the most investigated metabolites for DNA damage is 8-hydroxy-2-deoxyguanosine (8-OhdG), which is accepted as a biomarker of oxidative damage to DNA. In our study, we planned to investigate DNA damage and important predisposing factors for contrast nephropathy using oxidative stress markers. Method Between February 2021 and April 2022, blood was taken from 191 patients who underwent coronary angiography (CAG) by the Cardiology Department at ESOGU before CAG and at 72 hours after CAG. Patients who met the criteria for contrast nephropathy development (those with a serum creatinine increase of 25% or more compared to baseline or an increase of 0.5 mg/dl or more) were included as the case group in our study. Our study is a prospective study consisting of 85 cases and 106 controls, totaling 191 participants. TAS, TOS, OSI, and 8-OhDG levels were compared between both groups and before-after procedure. This study was supported by ESOGU BAP project number 1621. Results The mean age of the developing group was calculated as 68.13 ± 10.37, while it was calculated as 61.03 ± 9.97 in the control group (p = 0.00). In the case group, there were 30 (35.3%) without heart failure, while there were 75 (70.8%) without heart failure in the control group (p = 0.00). In univariate analyzes, we found that advanced age and heart failure were the most important indicators for KMN. When we compared those with and without KMN, we saw that TOS values decreased less in the group with post-angiography nephropathy than in those without it. We found a positive correlation between uric acid and TAS. In the KMN group, it was found that there was a statistically significant increase in TAS value after CAG, while there was a decrease in OSI value, and no statistically significant difference was found for TOS and 8-OhDG. In patients who underwent percutaneous intervention, it was found that there was a statistically significant increase in TAS value after CAG, while TOS and OSI decreased, and no significant difference was found for 8-OhDG. Conclusion Although previous studies have shown that oxidative stress plays an important role in contrast nephropathy pathogenesis, a strong relationship between KMN development and oxidative stress could not be found in our study. Our study is the first study to examine DNA damage with 8-OhDG in KMN, and it has been shown that there is no increase in DNA damage with KMN development. It is thought that one of the reasons leading to this result may be that contrast agents used today are selected as less toxic substances used in less volumes during processing, which may prevent DNA damage from occurring. Another result reached in our study is that TAS level increased in patients undergoing percutaneous intervention, while TOS and OSI decreased; that is, revascularization can reduce TOS and ultimately oxidative status.”

#1591 Analysis of microvesicles and their relationship with oxidative stress as biomarkers of cardiovascular damage in chronic kidney disease

Abstract Background and Aims Chronic kidney disease (CKD) is associated with a higher incidence of cardiovascular diseases. These diseases are preceded by endothelial dysfunction and alterations in coagulation systems. One of the challenges of research in this field is the search for diagnostic and predictive biomarkers of cardiovascular pathology. Our hypothesis is that endothelial dysfunction and cardiovascular risk could be evidenced by the increased release of endothelial microvesicles (EMVs) and platelet microvesicles (PMVs), as well as a greater expression of tissue factor (TF). We also propose a relationship between the release of microvesicles and the oxidative stress observed in these patients. The aim of the study was to analyze the levels of MVEs and MVPs, the expression of FT and its relationship with pro-oxidant and antioxidant parameters as possible early biomarkers of cardiovascular and thrombotic risk in different stages and treatments of CKD. Method It is a cross-sectional study consisted of 116 patients (40 with advanced chronic disease (CKD), 40 undergoing hemodialysis (HD) and 36 undergoing peritoneal dialysis (PD)), as well as 17 healthy subjects (CT). Microvesicle phenotyping was performed by direct immunofluorescence and flow cytometry in plasma isolated by centrifugation from peripheral blood. The analysis of oxidative stress parameters was carried out by spectrophotometry, after isolation of plasma and mononuclear and polymorphonuclear leukocytes by means of a ficoll gradient. Results Patients on PD have higher plasma PMVs levels (p = 0.0005 vs ACKD and p = 0,0002 vs HD), while those on HD and PD have higher levels of EMVs compared to ACKD (p = 0,0001 and p = 0,0125, respectively). FT expression in PMVs is lower in HD (p &amp;lt; 0.0001 vs ACKD) and FT expression in EMVs is lower in HD and PD compared to ACKD (p = 0,0004 and p= 0.0033, respectively) (Fig. 1). Patients with CKD have a higher activity of pro-oxidant enzymes (XO, GPx), as well as high levels of lipid peroxidation by-products (TBARS-MDA) and lower activity of antioxidant enzymes (GSH, CAT, SOD) at the plasma and cellular level. A positive relationship has been observed between pro-oxidant parameters and the release of MVP and MVE, as well as the expression of FT (Table 1). Patients with cardiovascular events during the years of follow-up have higher levels of FT expressed in microvesicles, and long-term survival decreases in patients with elevated FT levels. Conclusion Patients with CKD have higher plasma levels of PMVs and EMVs and higher FT expression, related to a state of oxidative stress. These parameters could be considered as biomarkers for predicting, diagnosing, and prognostic cardiovascular events in CKD.