Development and application of oxidative stress biomarkers

Supervised Cycling Training Improves Erythrocyte Rheology in Individuals With Peripheral Arterial Disease

Peripheral arterial disease (PAD) results in insufficient flow to lower extremities. Aerobic exercise provides health benefits for individuals with PAD, but basic science behind it is still debated. Twenty-one PAD patients aged about 70 years with female/male as 7/14 were recruited. Among them, 11 were randomized to have supervised cycling training (SCT) and 10 to receive general healthcare (GHC) as controls. SCT participants completed 36 sessions of SCT at the first ventilation threshold within 12 weeks and the controls received GHC for 12 weeks. Ankle-brachial index (ABI), 6-min walk test (6MWT), peak oxygen consumption (V˙O_2peak), minute ventilation (V˙_E), minute carbon dioxide production (V˙CO₂), erythrocyte rheology, including the maximal elongation index (EI_max) and shear stress at 50% of maximal elongation (SS_1/2), and the Short Form-36 (SF-36) questionnaire for quality of life (QoL) were assessed before and 12 weeks after initial visit. SCT significantly decreased the SS_1/2 as well as SS_1/2 to EI_max ratio (SS_1/2/EI_max) and increased the erythrocyte osmolality in the hypertonic region as well as the area under EI-osmolality curve. The supervised exercise-induced improvement of erythrocyte deformability could contribute to the increased peripheral tissue O₂ delivery and was possibly related with increased V˙O_2peak. The physiological benefit was associated with significantly increased ABI, 6-min walking distance, cardiorespiratory fitness, and SF-36 score. However, no significant changes in aerobic capacity and erythrocyte rheological properties were observed after 12-week of GHC. In conclusion, SCT improves aerobic capacity by enhancing erythrocyte membrane deformability and consequently promotes QoL in PAD patients.

Effectiveness of the polyphenols-rich Sedum dendroideum infusion on gastric ulcer healing in rats: Roles of protective endogenous factors and antioxidant and anti-inflammatory mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Peptic ulcer is an inflammatory disease that therapeutic options are mainly focused in antisecretory drugs. Sedum dendroideum Moc & Sessé ex DC (Crassulaceae) is employed in folk medicine for the treatment of gastric ulcers. Recently, our group demonstrated that Sedum dendroideum infusion (SDI) is rich in polyphenols (flavonol glycosides, myricetin, quercetin and kaempferol) and promoted gastroprotection against acute ulcer models, without changes gastric acid secretion.

AIM OF THE STUDY

Here, we follow the investigation of the healing effects of SDI (ED₅₀ = 191 mg/kg) in the chronic gastric ulcer model induced by 80% acetic acid in rats, elucidating underlying mechanisms.

MATERIAL AND METHODS

Rats were orally treated with vehicle (water, 1 mL/kg), SDI (191 mg/kg), omeprazole (40 mg/kg) or sucralfate (100 mg/kg) twice daily for 5 days after ulcer induction. Following treatments, toxicological effects, macroscopic ulcer appearance, microscopic histological (HE, mucin PAS-staining) and immunohistochemical (PCNA and HSP70) analysis, inflammatory (MPO and NAG activity, cytokine levels measurements) and antioxidant (SOD and CAT) parameters were investigated in gastric ulcer tissues.

RESULTS

Oral treatment with SDI accelerated gastric ulcer healing, maintained mucin content and promoted epithelial cell proliferation. SDI also reduced neutrophil and mononuclear leukocyte infiltration, TNF-α and IL-1β levels and the oxidative stress, restoring SOD and CAT activities in the ulcer tissue.

CONCLUSIONS

The gastric healing effect of SDI was mediated through endogenous protective events as well as due to the anti-inflammatory and antioxidant actions. Our observations support and reinforce the traditional utilize of Sedum dendroideum as a natural nontoxic therapeutic alternative for the treatment of gastric ulcers.

Potential contribution of ELISA and LFI assays to assessment of the oxidative stress condition based on 8-oxodG biomarker

Immunoassays have been extensively applied in the medical diagnostic field. Enzyme-Linked Immunosorbent Assay (ELISA) and Lateral Flow Immunochemical Assay (LFIA) are methods that have been well established to analysis of clinical substances such as protein, hormones, drugs, identification of antibodies and in the quantification of antigen. Over the past years, the application of these methods has been extended to assess the clinical oxidative stress condition based on monitoring of the 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) biomarker levels. The present manuscript provides an overview of the current immunoassays based on ELISA and LFIA technologies applied for a quantitative analysis of the 8-oxodG. The discussion focuses on the principles of development, improvement and analytical performance of these assays. The relationship of the molecule 8-oxodG as a clinical biomarker of the assessment of the oxidative stress condition is also discussed. Commercially available products to 8-oxodG analysis are also presented.

Oxidative stress in vascular calcification

Vascular calcification (VC), which is closely associated with significant mortality in cardiovascular disease, chronic kidney disease (CKD), and/or diabetes mellitus, is characterized by abnormal deposits of hydroxyapatite minerals in the arterial wall. The impact of oxidative stress (OS) on the onset and progression of VC has not been well described. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, xanthine oxidases, myeloperoxidase (MPO), nitric oxide synthases (NOSs), superoxide dismutase (SOD) and paraoxonases (PONs) are relevant factors that influence the production of reactive oxygen species (ROS). Furthermore, excess ROS-induced OS has emerged as a critical mediator promoting VC through several mechanisms, including phosphate balance, differentiation of vascular smooth muscle cells (VSMCs), inflammation, DNA damage, and extracellular matrix remodeling. Because OS is a significant regulator of VC, antioxidants may be considered as novel treatment options.

Hemistepsin A protects human keratinocytes against hydrogen peroxide-induced oxidative stress through activation of the Nrf2/HO-1 signaling pathway

Hemistepsin A, a sesquiterpene lactone compound isolated from Hemistepta lyrata, has been identified a variety of pharmacological actions including anti-hepatotoxic, anti-inflammatory and anti-cancer activities. Nevertheless, the antioxidant effects of hemistepsin A and the underlying mechanisms have not been investigated properly. Therefore, in the present study, we investigated the protective effect of hemistepsin A against oxidative stress in HaCaT human keratinocytes. The results demonstrated that hemistepsin A suppressed 500 μM hydrogen peroxide (H₂O₂)-induced cytotoxicity and DNA damage by blocking ROS accumulation. 10 μM Hemistepsin A also prevented apoptosis by preventing the mitochondrial dysfunction and the cytosolic release of cytochrome c, reducing the rate of Bax/Bcl-2 expression, and decreasing the activation of caspase-9 and caspase-3, suggesting that hemistepsin A protected cells from H₂O₂-induced mitochondria-mediated apoptosis. In addition, hemistepsin A markedly promoted the activation of nuclear factor-erythroid-2-related factor 2 (Nrf2), which was associated with the enhanced expression and activity of heme oxygenase-1 (HO-1) in the presence of 500 μM H₂O₂. However, inhibiting the expression of HO-1 by artificially blocking the expression of Nrf2 or HO-1 using siRNA significantly eliminated the protective effect of hemistepsin A, indicating that hemistepsin A activates the Nrf2/HO-1 signaling pathway in HaCaT cells to protect against oxidative stress. Therefore, these results suggest that hemistepsin A may be useful as a potential therapeutic agent against various oxidative stress-related skin diseases.

Reduced cutaneous inflammation associated with antioxidant action after topical application of the aqueous extract of Annona muricata leaves

Annona muricata L. is used in folk medicine for treatment of diseases related to inflammatory and oxidative processes. This study investigated the effect of the aqueous extract of A. muricata leaves (AEAM) on TPA-induced ear inflammation and antioxidant capacity, both in vitro and in vivo. The in vitro antioxidant capacity of AEAM was measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing/antioxidant power (FRAP) and lipoperoxidation assays. Cytotoxicity and reactive oxygen species (ROS) release were evaluated in the L929 fibroblasts. Swiss mice were submitted to TPA application and were topically treated with AEAM (0.3, 1 or 3 mg/ear). After 6 h, inflammatory and oxidative parameters were evaluated. Quercetin 3-glucoside, rutin, chlorogenic acid, catechin and gallic acid were identified in AEAM. It also presented antioxidant activity in all in vitro assays used. Incubation with AEAM did not cause cell cytotoxicity but reduced ROS release from fibroblasts. Compared with the control group, treatment with AEAM significantly reduced ear oedema and mieloperoxidase activity in inflamed ears, as well as histological parameters of inflammation. These results were associated with the reduction of total hydroperoxides and modulation of catalase, but not superoxide dismutase activity. These findings show the anti-inflammatory effect of AEAM is associated with antioxidant capacity.

Selenium attenuates diclofenac-induced testicular and epididymal toxicity in rats

The adverse effect of diclofenac administration on the male reproductive organ in both humans and rats has been reported. Selenium, a trace element vital in nutrition, plays a significant part in cellular redox homeostasis, including male reproduction. However, the impact of selenium on male reproductive toxicity associated with diclofenac administration is lacking in the literature. The current investigation assessed the modulatory effects of selenium on diclofenac-mediated reproductive toxicity in rats. Rats were treated for fourteen consecutive days, either with diclofenac (10 mg/kg) or co-treated with selenium (0.125 and 0.25 mg/kg) body weight. Sperm parameters, enzymes of testicular function, luteinizing, follicle-stimulating hormone and testosterone were assessed in addition to oxidative stress indices and histopathological changes. Selenium significantly alleviated diclofenac-induced decreases in sperm count and motility, testicular function enzymes and levels of luteinizing hormone and testosterone in serum. Moreover, selenium co-administration at 0.125 and 0.25 mg/kg inhibited the diclofenac-induced decrease of antioxidant enzyme activities and increased oxidative stress parameters-lipid peroxidation, reactive nitrogen and oxygen species-in epididymis and testes of rats. Selenium (0.25 mg/kg) alone ameliorated diclofenac-mediated histological injuries in exposed rats. Collectively, selenium enhanced testicular and epididymal function in diclofenac-treated rats by suppressing nitrosative and oxidative stress in rats.

Suboptimal health pregnant women are associated with increased oxidative stress and unbalanced pro- and antiangiogenic growth mediators: a cross-sectional study in a Ghanaian population

Optimal oxidative stress (OS) is important throughout pregnancy; however, an increased OS may alter placental angiogenesis culminating in an imbalanced of angiogenic growth mediators (AGMs). Suboptimal Health Status (SHS), a physical state between health and disease, may be associated with increased OS and unbalanced AGMs. In this study, we explored the association between SHS, biomarkers of OS (BOS) and AGMs among normotensive pregnant women (NTN-PW) in a Ghanaian Suboptimal Health Cohort Study (GHOACS). This comparative GHOACS recruited 593 NTN-PW from the Komfo Anokye Teaching Hospital, Ghana. SHS was measured using a Suboptimal Health Status Questionnaire-25 (SHSQ-25). Along with the subjective SHS measure, objective BOS: 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-epiprostaglandinF2 alpha (8-epi-PGF2α), total antioxidant capacity (TAC), and AGMs: vascular endothelial growth factor-A (VEGF-A), soluble fms-like tyrosine kinase receptor 1 (sFlt-1), placental growth factor (PIGF) and soluble endoglin (sEng) were evaluated. Compared to optimal health NTN-PW, levels of PlGF, VEGF-A and TAC were significantly (p < 0.05) reduced and negatively associated with SHS whilst sEng, sFlt-1, 8-epiPGF2α, 8-OHdG, and combined ratios of sFlt-1/PlGF, 8-epiPGF2α/PlGF, 8-OHdG/PlGF, and sEng/PlGF were significantly increased and positively associated with SHS. The first quartile for PIGF (2.79-fold) and VEGF-A (5.35-fold), and the fourth quartile for sEng (4.31-fold), sFlt-1 (1.84-fold), 8-epiPGF2α (2.23-fold), 8-OHdG (1.90-fold) and urinary 8-OHdG (1.95-fold) were independently associated with SHS (p < 0.05). SHS is associated with increased OS and unbalanced AGMs. Early identification of SHS-related OS and unbalanced AGMs may inform clinicians of the need for therapeutic options.