Protein Oxidation Research Articles

INDICATORS OF FREE RADICAL OXIDATION AND ANTIOXIDANT PROTECTION IN THE ORAL FLUID OF CHILDREN WITH CHRONIC CATARRHAL GINGIVITIS AND DIABETIS MELLITUS

Failure of antioxidant mechanisms leads to an increase in lipid peroxidation products in the body, resulting in a non-specific cascade of cellular membrane damage. Proteins play a crucial role in metabolic processes, but when lipid peroxidation intensifies, protein modifications occur, leading to fragmentation, denaturation, and loss of biological activity. This disruption impairs tissue regenerative processes. The objective of this study was to analyze indicators of free radical oxidation and antioxidant protection in the oral fluid of children with chronic catarrhal gingivitis and type I diabetes mellitus. Materials and methods. A total of 170 children aged 12 to 16 were observed, including 130 who were examined and treated at the Endocrinology Department of the Regional Municipal Non-Profit Institution “Chernivtsi Regional Pediatric Clinical Hospital” for type 1 diabetes mellitus. Among them, 74 children had a disease duration of less than 5 years, including 65 with chronic catarrhal gingivitis. Sixty five children had diabetes for more than 5 years, with 44 of them diagnosed to have chronic catarrhal gingivitis. The children with chronic catarrhal gingivitis were further divided into groups based on their level of glycemic control: 1 child with optimal glycemic control, 66 with suboptimal glycemic control, and 42 with glycemic control at a high risk to life. The control group included 40 practically healthy children: 22 of them had clinically healthy periodontal tissues, and 18 children were diagnosed to suffer from chronic catarrhal gingivitis. Results. The study performed found out that children with chronic catarrhal gingivitis present increased indicators of lipid peroxide oxidation (protein oxidative modification, diene conjugates, malondialdehyde) and decreased activity of the enzyme in the antioxidant protective system of the oral fluid (whole protein, НS-groups, ceruloplasmin, activity of supermutase and catalase) in comparison with indicators of children without dental pathology. The most considerable changes were found in patients with chronic catarrhal gingivitis and type 1 diabetes mellitus, especially when the disease lasted more than 5 years (р<0,05).

High dose of liraglutide impairs renal function in female hypertensive rats

Glucagon-like peptide-1 (GLP-1) receptor agonists exhibit beneficial cardiovascular effects. However, the renal effects of different doses of liraglutide in an essential hypertension model have not yet been investigated. SHR female rats were treated for 30 days, twice a day, with saline (control) or liraglutide at low (0.06 mg/kg, LL) and high (0.6 mg/kg, LH) doses. Volume intake and excretion were monitored for a period of 24h. In renal tissue, nitrite-NO2 -, nitrate-NO3 -, advanced protein oxidation products-AOPP, collagen deposition, creatinine (Cr), urea (U), sodium, and potassium were analyzed. liraglutide reduced body weight gain in both groups. However, in the high dose, it increased urinary volume excretion and sodium/potassium ratio. Both doses reduced the urinary U/Cr ratio and LH increased the serum U/Cr ratio. AOPP was reduced only in LL. LH augmented collagen and early markers of kidney injury (blood urea nitrogen-BUN, BUN/Cr). LH increased NO3 -, reduced NO2 -, and caused an aberrant increase in GFR. Both doses’ effects were independent of blood pressure and glycemic control. liraglutide appears to have distinct effects on the hypertensive female kidney depending on the dose, with higher doses impairing kidney function.

Accumulation of advanced oxidation protein products promotes age-related decline of type H vessels in bone.

Type H vessels have been proven to couple angiogenesis and osteogenesis. The decline of type H vessels contributes to bone loss in the aging process. Aging is accompanied by the accumulation of advanced oxidation protein products (AOPPs). However, whether AOPP accumulation is involved in age-related decline of type H vessels is unclear. Here, we show that the increase of AOPP levels in plasma and bone were correlated with the decline of type H vessels and loss of bone mass in old mice. Exposure of microvascular endothelial cells to AOPPs significantly inhibited cell proliferation, migration, and tube formation, increased NADPH oxidase activity and excessive reactive oxygen species generation, upregulated the expression of vascular cell adhesion molecule-1 and intercellular cell adhesion molecule-1, and eventually impaired angiogenesis, which was alleviated by redox modulator N-acetylcysteine and NADPH oxidase inhibitor apocynin. Furthermore, reduced AOPP accumulation by NAC treatment was able to alleviate significantly the decline of type H vessels, bone mass loss and deterioration of bone microstructure in old mice. Collectively, these findings suggest that AOPPs accumulation contributes to the decline of type H vessels in the aging process, and illuminate a novel potential mechanism underlying age-related bone loss.

Influence of (ultra-)processing methods on aquatic proteins and product quality.

Aquatic products are a high-quality source of protein for humans, and the changes in protein during aquatic product processing are crucial for nutritional value, product performance, and consumer health. With the advancement of science and technology, aquatic product processing methods have become increasingly diverse. In addition to traditional methods such as thermal processing (steaming, roasting, and frying) and pickling, emerging non-thermal processing technologies, such as high pressure, ultrasound, and irradiation, are also being applied. During (ultra-)processing, aquatic products undergo complex biochemical reactions, among which protein oxidation significantly affects the quality of aquatic products. Protein oxidation can alter the molecular structure of proteins, thereby changing their functional properties and ultimately impacting product quality. This paper primarily explored the effects of protein changes under different processing methods on aquatic product quality and human health, as well as techniques for controlling protein oxidation. It aims to provide a theoretical basis for selecting appropriate processing methods, improving aquatic product quality, and controlling protein oxidation in aquatic products, and to offer scientific guidance for practical production.

Antioxidant and Nutritional Potential of Artichoke (Cynara scolymus L.) By-Product Extracts in Fat-Replaced Beef Burgers with Hydrogel Emulsions from Olive Oil

Beef burger consumption has been questioned due to the burgers’ high levels of saturated fatty acids and the use of synthetic additives for preservation. In order to improve the acceptability and health benefits of this product, two functional ingredients, artichoke and extra-virgin olive oil (EVOO), have been used to formulate four different beef burgers: a control burger (CB), a fat-replaced burger with an EVOO emulsion (FRB), and two FRB formulations with the incorporation of enzymatically treated (FRB-TAE) or untreated (FRB-AE) artichoke extract. Fat replacement significantly affected the lipid profile of the burgers, increasing oleic acid levels and n-3 PUFA such as α-linolenic and eicosapentaenoic acids. Artichoke incorporation exerted beneficial effects on the antioxidant activity, as well as on the total phenolic content of the reformulated burgers, leading to a decrease in color changes, lipid and protein oxidation after 3 days of storage at 4 °C, as well as reducing the formation of volatile compounds such as hexanal, 2,3-Octanedione, or 1-Octen-3-ol. No differences were found between formulations for the sensory parameters studied. These results demonstrate a possible revalorization of artichoke by-products by improving the nutritional properties of beef burgers, revealing a potential application as a higher value-added ingredient in the meat industry.

Upregulation of ACSL, ND75, Vha26 and sesB genes by antiepileptic drugs resulted in genotoxicity in drosophila.

Clobazam (CLB) and Vigabatrin (VGB) are commonly used antiepileptic drugs (AEDs) in the treatment of epilepsy. Here, we have examined the genotoxic effect of these AEDs in Drosophila melanogaster. The Drosophila larvae were exposed to different concentrations of CLB and VGB containing food media. The assessment encompassed oxidative stress, DNA damage, protein levels, and gene expression profiles. In the CLB-treated group, a reduction in reactive oxygen species (ROS) and lipid peroxidation (LPO) levels was observed, alongside increased levels of superoxide dismutase (SOD), catalase (CAT), and nitric oxide (NO). Conversely, the VGB-treated group displayed contrasting results, with increased ROS and LPO and decreased SOD, CAT, and NO levels. However, both CLB and VGB induced DNA damage in Drosophila. Proteomic analysis (SDS-PAGE and OHRLCMS) in the CLB and VGB groups identified numerous proteins, including Acyl-CoA synthetase long-chain, NADH-ubiquinone oxidoreductase 75kDa subunit, V-type proton ATPase subunit E, ADP/ATP carrier protein, malic enzyme, and DNA-binding protein modulo. These proteins were found to be associated with pathways like growth promotion, notch signaling, Wnt signaling, neuromuscular junction (NMJ) signaling, bone morphogenetic protein (BMP) signaling, and other GABAergic mechanisms. Furthermore, mRNA levels of ACSL, ND75, Vha26, sesB, and Men genes were upregulated in both CLB and VGB-treated groups. These findings suggest that CLB and VGB could have the potential to induce genotoxicity and post-transcriptional modifications in humans, highlighting the importance of monitoring their effects when used as AEDs.

Association of ambient ozone exposure with early cardiovascular damage among general urban adults: A repeated-measures cohort study in China

Longitudinal evidence of long-term ozone exposure on heart rate variability (HRV, an early indicator of cardiovascular damage) is lacking and the potential mechanism remains largely unclear. Our objectives were to evaluate the cross-sectional and longitudinal associations of ozone exposure with HRV alteration, and the potential roles of protein carbonyl (PC, biomarker of oxidative protein damage) and transforming growth factor (TGF)-β1 in this association. This repeated-measures prospective study included 4138 participants with 6617 observations from the Wuhan-Zhuhai cohort. Ozone concentrations were estimated using a high temporospatial resolution model for each participant. HRV indices, PC, and TGF-β1 were also repeatedly measured. Cross-sectional and longitudinal relationships of ozone exposure with HRV alteration were evaluated by linear mixed model. Cross-sectionally, the strongest lag effect of each 10 ppb increment in short-term ozone exposure showed a 12.40 %, 8.47 %, 4.31 %, 8.03 %, 3.69 %, and 2.41 % decrement on very low frequency (VLF, lag 3 weeks), LF (lag 2 weeks), high frequency (HF, lag 0–7 days), total power (TP, lag 2 weeks), standard deviation of all normal-to-normal intervals (SDNN, lag 3 weeks), and square root of the mean squared difference between adjacent normal-to-normal intervals (lag 2 weeks), respectively. Longitudinally, each 10 ppb increment of annual average ozone was related with an annual change rate of −0.024 ms2/year in VLF, −0.009 ms2/year in LF, −0.013 ms2/year in HF, −0.014 ms2/year in TP, and −0.004 ms/year in SDNN. Mediation analyses indicated that PC mediated 20.77 % and 12.18 % of ozone-associated VLF and TP decline, respectively; TGF-β1 mediated 16.87 % and 27.78 % of ozone-associated VLF and SDNN reduction, respectively. Our study demonstrated that ozone exposure was cross-sectionally and longitudinally related with HRV decline in general Chinese urban adults, and oxidative protein damage and increased TGF-β1 partly mediated ozone exposure-related HRV reduction.

Redox proteomic analysis of H2O2 -treated Jurkat cells and effects of bicarbonate and knockout of peroxiredoxins 1 and 2

Oxidation of thiol proteins and redox signaling occurs in cells exposed to H2O2 but mechanisms are unclear. We used redox proteomics to seek evidence of oxidation of specific proteins either by a mechanism involving reaction of H2O2 with CO2/bicarbonate to give the more reactive peroxymonocarbonate, or via a relay involving peroxiredoxins (Prdxs). Changes in oxidation state of specific Cys-SH residues on treating Jurkat T lymphoma cells with H2O2 were measured by isotopically labeling reduced thiols and analysis by mass spectrometry. The effects of bicarbonate and of knocking out either Prdx1 or Prdx2 were examined. Approximately 14,000 Cys-peptides were detected, of which ∼ 1% underwent 2-10 fold loss in thiol content with H2O2. Those showing the most oxidation were not affected by the presence of bicarbonate or knockout of either Prdx. Consistent with previous evidence that bicarbonate potentiates inactivation of glyceraldehyde-3-phosphate dehydrogenase, the GAPDH active site Cys residues were significantly more sensitive to H2O2 when bicarbonate was present. Several other proteins were identified as promising candidates for further investigation. Although we identified some potential protein candidates for Prdx- dependent oxidation, most of the significant differences between KO and WT cells were seen in proteins for which H2O2 unexpectedly increased their CysSH content over untreated cells. We conclude that facilitation of protein oxidation by bicarbonate or Prdx-mediated relays is restricted to a small number of proteins and is insufficient to explain the majority of the oxidation of cell thiols that occurs in response to H2O2.

Differential contribution of Cu2+ and OH− to the formation of Nε-carboxymethyllysine and Nε-carboxyethyllysine in preserved egg white during pickling

In this study, the relationship between advanced glycosylation end products (AGEs) in preserved egg white (PEW) with protein oxidation and precursors induced by OH− and Cu2+ were performed to clarify the differential contribution of OH− and Cu2+ on the formation of AGEs during pickling. It was found that AGEs were more easily formed in PEW rather than yolk, and the accumulation of Nε-carboxymethyllysine (CML) could be promoted through protein oxidation related to carbonyl compounds, tryptophan induced by Cu2+ at early stage, while carbonyl compounds were more conducive to form Nε-carboxyethyllysine (CEL) under synergistic action of Cu2+ and OH−. At later period, Schiff base promoted the formation of CEL and CML in the presence of Cu2+. Meanwhile, the enrichment of CEL and CML could both be promoted by α-dicarbonyl compounds in presence of Cu2+ and/or OH−. This manuscript will provide theoretical guidance for reducing and limiting hazardous compounds in preserved eggs.

Exploring the ameliorative potential of rutin against High-Sucrose Diet-induced oxidative stress and reproductive toxicity in Drosophila melanogaster

Sucrose is a vital ingredient in numerous food items consumed regularly. However, exposure to excessive sucrose for a prolonged period can promote health issues. The reproductive system has a delicate physiology that can be targeted by various chemical stressors, including sucrose. Hence, the present in vivo study aims to unveil the impacts of the High-Sucrose Diet (HSD) on the reproductive fitness of Drosophila melanogaster. In addition, the present work has also assessed the protective potential of a bioactive compound, rutin, against it. Here, 1st instar larvae were exposed to HSD (30%) alone and in combination with rutin (100-300µM) till their adult stage. HSD disturbed sex comb morphology in adult males, while fecundity and hatchability of eggs in females. Moreover, HSD triggered gonadal ROS production, oxidative stress, and modulated endogenous antioxidants such as SOD, catalase, and glutathione in both sexes. Nuclear fragmentation and tissue injuries, along with protein and lipid oxidation, were also apparent. Elevated levels of cytosolic Iron suggested an active Fenton reaction in adults. Further, HSD modulated the activities of reproductive and metabolic mediators, including vitellogenin, malate dehydrogenase, glucose-6-phosphate dehydrogenase, and angiotensin-converting enzymes that are critical to overall reproductive fitness. Interestingly, co-treatment with rutin, mainly at 200µM, mitigated these adverse effects and restored reproductive fitness. The protective potential of rutin might be attributed to its ability to normalize redox homeostasis, reduce oxidative stress, and optimize critical enzymes involved in reproductive physiology. These findings suggest that rutin has potential therapeutic implications to counteract the reproductive hazards induced by HSD.

Towards a dynamic model of indispensable amino acid requirements of the adult human: A factorial estimate of oxidative amino acid losses

BackgroundConsensus regarding the required intake of indispensable amino acids (IDAAs) and protein (representing total AAs) in the adult is lacking. Oxidation is a major, though not exclusive, source of IDAA loss in the human body and a primary factor determining requirements; a quantitative understanding of oxidative IDAA losses is required. ObjectiveTo develop a factorial diurnal model of total oxidative IDAA and protein losses in the adult human. MethodsA factorial diurnal model of oxidative losses of protein and each IDAA at maintenance was developed by estimating the magnitude and variability of sources of oxidative loss from existing literature: inevitable catabolism (constitutive oxidation of each absorbed dietary AA), and protein turnover in the postprandial and postabsorptive states. Total oxidative losses were calculated by summing individual losses, validated against published independent nitrogen balance data and compared to current IDAA requirements. ResultsThe factorial model predicted minimum oxidative total AA losses of 390±60 mg.kgBW-1.day-1, 59% of the EAR for protein. Inevitable AA oxidation and oxidation associated with postabsorptive protein turnover were the major sources of the oxidative loss for protein, at 40% and 44%, respectively. Summed oxidative IDAA losses ranged from 64% (isoleucine) to 91% (tryptophan) of current requirements. Total oxidative losses predicted by the model were significant predictors of actual experimental oxidative losses obtained by nitrogen balance (R2=0.66; p=0.049). ConclusionsThe use of a factorial model for estimation of minimum IDAA and protein oxidative losses in the adult human provides an essential starting point for an updated understanding of protein and IDAA requirements. Further iterations of the model will estimate total protein and IDAA requirements, and account for variations in dietary protein quantity and quality, as well as different populations and physiological states. Additional data, especially for inevitable oxidation in humans, and particularly with respect to individual IDAAs, are needed.

Impact of Storage Temperature on Physical Stability and Protein-Lipid Co-oxidation in Whey Protein functional Emulsions.

The aim of this study was to investigate the effect of different storage temperatures (4°C, 25°C and 45°C, denoted as T-4, T-25 and T-45, respectively) on the physical stability and protein-lipid co-oxidation of whey protein functional emulsions during the storage period at storage times of 1, 2, 3 and 6 months. At the 6th month of storage, samples stored at 45°C were less physically stable than samples stored at 4°C, as evidenced by an increase in particle size (5.50%), a decrease in zeta potential (7.93%), and a decrease in adsorbed protein concentration (36.8%). The most severe protein-lipid co-oxidation was induced in whey protein functional emulsions under 45°C temperature conditions with increasing storage time. Protein oxidation products (carbonyls, N′-formyl-L-kynurenine, and sulfhydryl groups) and lipid oxidation products (lipid hydroperoxides, thiobarbituric acid reactive substances) were at their highest levels, and significant molecular changes were observed in the molecules of adsorbed protein or unadsorbed proteins. As the storage temperature rises it exposes the active sites such as internal sulfhydryl and hydrophobic groups in the protein, promoting cross-linking and aggregation. Cluster and correlation analyses showed that protein-lipid co-oxidation of emulsions inevitably occurs during storage, but low-temperature storage can delay this process. This study is of guiding significance for the quality maintenance of functional nutritional emulsions and the selection of storage conditions. In addition, this study may provide clearer solutions to the problems of whey protein denaturation and formation of lipid oxides caused by protein-lipid co-oxidation in the food industry, as well as to the problem of increasing the shelf life of products by choosing the appropriate storage, packaging, and transportation temperatures.

Insulin oxidation and oxidative modifications alter glucose uptake, cell metabolism, and inflammatory secretion profiles

Insulin participates in glucose homeostasis in the body and regulates glucose, protein, and lipid metabolism. Chronic hyperglycemia triggers oxidative stress and the generation of reactive oxygen species (ROS), leading to oxidized insulin variants. Oxidative protein modifications can cause functional changes or altered immunogenicity as known from the context of autoimmune disorders. However, studies on the biological function of native and oxidized insulin on glucose homeostasis and cellular function are lacking. Native insulin showed heterogenous effects on metabolic activity, proliferation, glucose carrier transporter (GLUT) 4, and insulin receptor (INSR) expression, as well as glucose uptake in cell lines of five different human tissues. Diverse ROS compositions produced by different gas plasma approaches enabled the investigations of variously modified insulin (oxIns) with individual oxidative post-translational modification (oxPTM) patterns as identified using high-resolution mass spectrometric analysis. Specific oxIns variants promoted cellular metabolism and proliferation in several cell lines investigated, and nitrogen plasma emission lines could be linked to insulin nitration and elevated glucose uptake. In addition, insulin oxidation modified blood glucose levels in the chicken embryos (in ovo), underlining the importance of assessing protein oxidation and function in health and disease.

JAK inhibition with tofacitinib rapidly increases contractile force in human skeletal muscle.

Reduction in muscle contractile force associated with many clinical conditions incurs serious morbidity and increased mortality. Here, we report the first evidence that JAK inhibition impacts contractile force in normal human muscle. Muscle biopsies were taken from patients who were randomized to receive tofacitinib (n = 16) or placebo (n = 17) for 48 h. Single-fiber contractile force and molecular studies were carried out. The contractile force of individual diaphragm myofibers pooled from the tofacitinib group (n = 248 fibers) was significantly higher than those from the placebo group (n = 238 fibers), with a 15.7% greater mean maximum specific force (P = 0.0016). Tofacitinib treatment similarly increased fiber force in the serratus anterior muscle. The increased force was associated with reduced muscle protein oxidation and FoxO-ubiquitination-proteasome signaling, and increased levels of smooth muscle MYLK. Inhibition of MYLK attenuated the tofacitinib-dependent increase in fiber force. These data demonstrate that tofacitinib increases the contractile force of skeletal muscle and offers several underlying mechanisms. Inhibition of the JAK-STAT pathway is thus a potential new therapy for the muscle dysfunction that occurs in many clinical conditions.

Characteristics of volatile flavor development in aged longissimus lumborum post-ultrasound treatment: 4D proteomics combined with phosphoproteomics analysis

The present study aimed to evaluate the impact of ultrasonic treatment on the development of volatile flavor compounds in beef during postmortem aging and its potential mechanism. Results showed that ultrasound treatment may cause an increase in the total content of unsaturated fatty acids, which could lead to lipid oxidation and potentially result in changes in the flavor development. Additionally, it was also found that ultrasound exacerbated protein oxidation. A total of 141 volatile compounds were obtained by SPME–GC–MS analysis, and 18 differential aroma substances (P < 0.05, VIP > 1) were obtained by orthogonal partial least squares discrimination analysis (OPLS-DA). Five key volatile flavor compounds (hexanal, nonanal, octanal, pentanal, and 1-pentanol) originating from lipid oxidation were identified according to odor activity values (OAVs). The concentration of these compounds was significantly higher in the ultrasonic treatment group compared to the non-ultrasonic group that underwent a 3-day aging process. Nine common differentially expressed proteins (DEPs) were identified through the utilization of proteomics and phosphoproteomics analysis. KEGG pathways showed that selenocompound metabolism, tryptophan metabolism and cysteine and methionine metabolism led to flavor formation during wet aging of beef after ultrasound treatment. This study provided proteomic insights into the flavor of beef aged through sonication and suggested potential links between flavor development and biological processes.

Oxidative stress in the alveolar lavage fluid of children with Mycoplasma pneumoniae pneumonia.

To investigate the correlation between oxidative stress in the bronchoalveolar lavage fluid (BALF) of children with Mycoplasma pneumoniae pneumonia (MPP) and the clinical characteristics of severe MPP (SMPP) and refractory MPP (RMPP). Clinical and BALF-related data were collected from 83 patients with MPP, of which 29 had SMPP and 54 had general MPP (GMPP); 37 patients were in the RMPP group and 46 in the non-RMPP group. The levels of malondialdehyde (MDA) and advanced oxidation protein products (AOPP) as well as the activity levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) in BALF were detected. Logistic regression analyses were performed on MDA, AOPP, SOD, GSH-PX, gender, heat peak, neutrophil percentage, C-reactive protein, lactate dehydrogenase, d-dimer, lung consolidation, sputum embolus, and pleural effusion. The levels of MDA and AOPP in the BALF of the MPP group were significantly higher than those in the control group (p < .05), whereas SOD and GSH-PX levels were lower than those in the control group (p < .05). The BALF AOPP levels in the RMPP group were higher than those in the non-RMPP group, and the SOD and GSH-PX levels in the BALF were lower than those in the non-RMPP group; the difference was statistically significant (p < .05). The levels of MDA and AOPP in the BALF of children in the SMPP group were higher than those in the GMPP group, and the levels of SOD and GSH-PX were lower than those in the GMPP group, with statistically significant differences (p < .05). The C-index of the logistic regression model was 0.960 (95% confidence interval 0.958-0.963), which indicates that the model has good predictive ability. Advanced oxidation protein products may be a marker for predicting the conditions of SMPP and RMPP, and the prediction model can assess the risk of progression in children to RMPP, which is conducive to clinical diagnosis and treatment.

Are Oxidative Stress Biomarkers Reliable Part of Multimarker Panel in Female Patients with Type 2 Diabetes Mellitus?

Background: Oxidative stress and inflammation are the key features of metabolic diseases, including type 2 diabetes mellitus (T2D). However, studies that explored redox homeostasis parameters in relation to T2D show discrepant results. Accordingly, we aimed to examine the potential reliability of oxidative stress biomarkers [i.e., determined by malondialdehyde (MDA), advanced oxidation protein products (AOPP) and catalase (CAT)] in addition to traditional cardiometabolic parameters in relation to T2D in female cohort. Methods: A total of 214 women (of them 40.6% T2D) were consecutively recruited in the study. Principal component analysis with varimax rotation was performed to determine the adequate number of factors consisting of anthropometric, traditional cardiometabolic and redox status markers. Results: MDA and AOPP concentrations were lower, but CAT activity was higher in T2D group as compared with controls (P < 0.001, P = 0.002, P < 0.001). Traditional markers related factor (i.e., with positive loading of waist circumference, triglycerides, uric acid, high sensitivity C-reactive protein and negative loadings of high-density lipoprotein cholesterol) was found to be independently related with T2D in multivariate binary regression analysis, whereas oxidative stress related factor (i.e., with positive loading of MDA and AOPP) lost its independent prediction after adjustment for confounding factors (i.e., age, menopausal status, antihypertensive, and hypolipemic therapies). Increased Traditional markers related factor was associated with more than three times higher probability for T2D onset (OR = 3.319, p < 0.001). Conclusion: Oxidative stress biomarkers, i.e., MDA, AOPP, and CAT are not superior over traditional cardiometabolic markers in relation to T2D in female population. Future studies with both gender included are needed to confirm such results.

Neuroprotective effect of chelidonic acid through oxidative stress reduction in paclitaxel-induced peripheral neuropathy in rats.

The present study evaluated the effect of chelidonic acid on paclitaxel-induced neuropathy in male Wistar rats. Neuropathy was induced by administering paclitaxel (2mg/kg, i.p.) on 0, 2, 4, and 6days of the protocol. Chelidonic acid treatment (at doses of 10, 20, and 40mg/kg orally, for 21days) was initiated simultaneously with paclitaxel administration. After completion of the protocol, mechanical allodynia, hyperalgesia, and thermal hyperalgesia were measured. Additionally, nerve conduction velocity was assessed. The study investigated inflammatory cytokines, oxidative stress, and histological changes in the sciatic nerve. Furthermore, the Nrf2 was measured, and the protein expression of pAMPK and HIF-1α was assessed using western blotting. The results showed that chelidonic acid significantly normalized mechanical allodynia, hyperalgesia, and thermal hyperalgesia. It also led to a significant improvement in motor and sensory nerve conduction velocity and reduced oxidative stress compared with paclitaxel alone. Inflammatory markers such as TNF-alpha, IL-6, and IL-1β concentrations, as well as nitric oxide and C-reactive protein, were significantly decreased in the chelidonic acid-treated group. Histopathological examination revealed reduced neuronal damage, demyelination, and leukocyte infiltration with chelidonic acid treatment. Chelidonic acid treatment also resulted in a considerable rise in Nrf2 levels (p < 0.001) and increased protein expression of pAMPK in the sciatic nerve. Conversely, HIF-1α expression was significantly declined in the chelidonic acid treatment. Overall, the findings suggest that chelidonic acid treatment attenuates paclitaxel-induced neuropathic pain.

Astragaloside IV Improves Muscle Atrophy by Modulating the Activity of UPS and ALP via Suppressing Oxidative Stress and Inflammation in Denervated Mice.

Peripheral nerve injury is common clinically and can lead to neuronal degeneration and atrophy and fibrosis of the target muscle. The molecular mechanisms of muscle atrophy induced by denervation are complex and not fully understood. Inflammation and oxidative stress play an important triggering role in denervated muscle atrophy. Astragaloside IV (ASIV), a monomeric compound purified from astragalus membranaceus, has antioxidant and anti-inflammatory properties. The aim of this study was to investigate the effect of ASIV on denervated muscle atrophy and its molecular mechanism, so as to provide a new potential therapeutic target for the prevention and treatment of denervated muscle atrophy. In this study, an ICR mouse model of muscle atrophy was generated through sciatic nerve dissection. We found that ASIV significantly inhibited the reduction of tibialis anterior muscle mass and muscle fiber cross-sectional area in denervated mice, reducing ROS and oxidative stress-related protein levels. Furthermore, ASIV inhibits the increase in inflammation-associated proteins and infiltration of inflammatory cells, protecting the denervated microvessels in skeletal muscle. We also found that ASIV reduced the expression levels of MAFbx, MuRF1 and FoxO3a, while decreasing the expression levels of autophagy-related proteins, it inhibited the activation of ubiquitin-proteasome and autophagy-lysosome hydrolysis systems and the slow-to-fast myofiber shift. Our results show that ASIV inhibits oxidative stress and inflammatory responses in skeletal muscle due to denervation, inhibits mitophagy and proteolysis, improves microvascular circulation and reverses the transition of muscle fiber types; Therefore, the process of skeletal muscle atrophy caused by denervation can be effectively delayed.

Flavin-containing monooxygenase 2 confers cardioprotection in ischemia models through its disulfide-bond catalytic activity.

Myocardial infarction (MI) is characterized by massive cardiomyocytes death and cardiac dysfunction, and effective therapies to achieve cardioprotection are sorely needed. Here we reported that flavin containing monooxygenase 2 (FMO2) level was markedly increased in cardiomyocytes both in ex vivo and in vivo models of ischemia injury. Genetic deletion of FMO2 resulted in reduced cardiomyocyte survival and enhanced cardiac dysfunction, whereas cardiomyocyte-specific FMO2 overexpression exerted a protective effect in infarcted rat hearts. Mechanistically, FMO2 inhibited the activation of endoplasmic reticulum (ER) stress-induced apoptotic proteins, including caspase 12 and C/EBP homologous protein (CHOP), by down-regulating unfolded protein response (UPR) pathway. Furthermore, we identified FMO2 as a chaperone that catalyzed disulfide-bond formation in unfolded/misfolded proteins through its GVSG motif. GVSG-mutated FMO2 failed to catalyze disulfide-bond formation and lost its protection against ER stress and cardiomyocyte death. Finally, we demonstrated the protective effect of FMO2 in human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) model. Collectively, this study highlights FMO2 as a key modulator of oxidative protein folding in cardiomyocytes and underscores its therapeutic potential for treating ischemic heart disease.