Alessandra Lourenço Cecchini

Photoaging and chronological aging profile: Understanding oxidation of the skin

The impact of chronological aging and photoaging on the skin is particularly concerning, especially when oxidative stress is involved. This article provides evidence of quantitative and qualitative differences in the oxidative stress generated by chronological aging and photoaging of the skin in HRS/J hairless mice. Analysis of the results revealed an increase in lipid peroxides as the skin gets older and in photoaged skin (10.086 ± 0.70 η MDA/mg and 14.303 ± 1.81 η MDA/mg protein, respectively), although protein oxidation was only verified in chronological aged skin (15.449 ± 0.99 η protein/mg protein). The difference between both skin types is the decay in the capacity of lipid membrane turnover revealed by the dislocation of older skin to the left in the chemiluminescence curve. Imbalance between antioxidant and oxidation processes was verified by the decrease in total antioxidant capacity of chronological and photoaged skins. Although superoxide dismutase remained unchanged, catalase increased in the 18 and 48-week-old skin groups and decreased in irradiated mice, demonstrating that neither enzyme is a good parameter to determine oxidative stress. The differences observed between chronological and photoaging skin represent a potential new approach to understanding the phenomenon of skin aging and a new target for therapeutic intervention.

Differential oxidative status and immune characterization of the early and advanced stages of human breast cancer

Breast cancer is the malignant neoplasia with the highest incidence in women worldwide. Chronic oxidative stress and inflammation have been indicated as major mediators during carcinogenesis and cancer progression. Human studies have not considered the complexity of tumor biology during the stages of cancer advance, limiting their clinical application. The purpose of this study was to characterize systemic oxidative stress and immune response parameters in early (ED; TNM I and II) and advanced disease (AD; TNM III and IV) of patients diagnosed with infiltrative ductal carcinoma breast cancer. Oxidative stress parameters were evaluated by plasmatic lipoperoxidation, carbonyl content, thiobarbituric reactive substances (TBARS), nitric oxide levels (NO), total radical antioxidant parameter (TRAP), superoxide dismutase, and catalase activities and GSH levels. Immune evaluation was determined by TNF-α, IL-1β, IL-12, and IL-10 levels and leukocytes oxidative burst evaluation by chemiluminescence. Tissue damage analysis included heart (total CK and CKMB), liver (AST, ALT, GGT), and renal (creatinine, urea, and uric acid) plasmatic markers. C-reactive protein (CRP) and iron metabolism were also evaluated. Analysis of the results verified different oxidative stress statuses occur at distinct cancer stages. ED was characterized by reduction in catalase, 8-isoprostanes, and GSH levels, with enhanced lipid peroxidation and TBARS levels. AD exhibited more pronounced oxidative status, with reduction in catalase activity and TRAP, intense lipid peroxidation and high levels of NO, TBARs, and carbonyl content. ED patients presented a Th2 immune pattern, while AD exhibited Th1 status. CRP levels and ferritin were increased in both stages of disease. Leukocytes burst impairment was observed in both the groups. Plasma iron levels were significantly elevated in AD. The data obtained indicated that oxidative stress enhancement and immune response impairment may be necessary to ensure cancer progression to advanced stages and may result from both host and tumor inflammatory mediators.

Time course of skeletal muscle loss and oxidative stress in rats with walker 256 solid tumor

Reactive oxygen species oxidize proteins and modulate the proteasomal system in muscle‐wasting cancer cachexia. On day 5 (D5), day 10 (D10), and day 14 (D14) after tumor implantation, skeletal muscle was evaluated. Carbonylated proteins and thiobarbituric acid reactive substances were measured. Chemiluminescence was employed for lipid hydroperoxide estimation. Glutathione, superoxide dismutase, and total radical antioxidant capacity were evaluated. The proteasomal system was assessed by mRNA atrogin‐1 expression. Increased muscle wasting, lipid hydroperoxide, and superoxide dismutase, and decreased glutathione levels and total radical antioxidant capacity, were found on D5 in accordance with increased mRNA atrogin‐1 expression. All parameters were significantly modified in animals treated with α‐tocopherol. The elevation in aldehylde levels and carbonylated proteins observed on D10 were reversed by α‐tocopherol treatment. Oxidative stress may trigger signal transduction of the proteasomal system and cause protein oxidation. These pathways may be associated with the mechanism of muscle wasting that occurs in cancer cachexia. Muscle Nerve 42: 950–958, 2010

Molecular subtype is determinant on inflammatory status and immunological profile from invasive breast cancer patients

Breast cancer consists in a chronic inflammatory disease with multiple biological and clinical behaviors. Based on high throughput technologies data, this disease is currently classified according to the molecular expression of estrogen (ER), progesterone (PR) and human epidermal growth factor (HER-2) receptors. In this study, we defined the inflammatory profile of the main molecular subtypes of breast cancer patients: luminal (ER and PR positive, HER-2 negative), HER-2 enriched (HER-2 positive) and triple negative (ER, PR and HER-2 negative). Cytokines panel was assessed by measurement of TNF-α, TGF-β, IL-1, IL-10 and IL-12 plasmatic levels. Oxidative profile was assessed by determination of lipid peroxidation, total antioxidant capacity of plasma, malondialdehyde levels, carbonyl content and nitric oxide (NO). Clinical data were correlated with inflammatory findings. Our findings demonstrated that patients bearing the luminal subtype displayed high TNF-α, TGF-β and enhanced oxidative stress levels associated with reduced IL-12. HER-2-enriched group exhibited higher levels of TNF-α, IL-12 and TGF-β associated with enhanced oxidative stress. Triple-negative subtype exhibited the most aggressive profile of disease behavior, with reduction in both TNF-α and TGF-β, with high levels of lipid peroxidation and NO. The clinical importance of our findings lies in the fact that the inflammatory status varies in distinct ways due to molecular subtype of breast cancer, opening potential therapeutic targets to future therapies.

Time-dependent reactive species formation and oxidative stress damage in the skin after UVB irradiation

This study provides evidence that skin oxidative stress injury caused by UVB irradiation is mediated predominantly by reactive oxygen species immediately after irradiation and by reactive nitrogen species at later time points. Animals were pre-treated with free radical scavengers (deferrioxamine, histidine), α-tocopherol, or inhibitors of nitric oxide synthase (NOS) (L-NAME or aminoguanidine) or left untreated and subjected to UVB irradiation. α-Tocopherol inhibited the increase in lipid peroxidation, as evaluated by chemiluminescence at 0 h and 24 h after UVB irradiation. Immediately after UVB irradiation, lipid peroxidation increased moderately and was abolished by free radical scavengers but not by NOS inhibitors. Likewise, the reduction of antioxidant capacity was not reversed by NOS inhibitors. Nitric oxide augmentation was not observed at this time point. Twenty-four hours after irradiation, increased lipid peroxidation levels and nitric oxide elevation were observed and were prevented by NOS inhibitors. Low concentrations of GSH and reduced catalase activity were also observed. Altogether, these data indicate that reactive oxygen species (singlet oxygen and hydroxyl radicals) are the principal mediators of immediate damage and that reactive nitrogen species (*NO and possibly ONOO(-)) seem to be involved later in skin oxidative injury induced by UVB radiation. The reduced catalase activity and low level of GSH suggest that *NO and H(2)O(2) may react to generate ONOO(-), a very strong lipid peroxidant species.

Systemic toxicity induced by paclitaxel in vivo is associated with the solvent cremophor EL through oxidative stress-driven mechanisms.

The toxic effects of paclitaxel (PTX) and its solubilizing agent cremophor EL (CREL) have been well established in vitro; however, the in vivo mechanisms underlying this toxicity remain unclear. Thus, the aim of this study was to analyze the in vivo toxicity induced by infusion of PTX and CREL and to investigate the involvement of oxidative stress as a potential mechanism for this toxicity. We treated male Wistar rats with PTX and/or CREL for 1h using human-equivalent doses (PTX+CREL/ethanol+NaCl 175mg/m(2) or CREL+ethanol+NaCl) and sacrificed immediately or 24h after these drug infusions to systemic biochemical evaluations. Hidrosoluble vitamin E (vitE, Trolox) was added as a control in some groups. The oxidative profile was determined by measuring erythrocyte and plasma lipid peroxidation, superoxide dismutase and catalase activities, reduced glutathione (GSH) levels, red blood cell (RBC) counts, hemoglobin profile, plasma total radical-trapping antioxidant parameter (TRAP), plasma lipid peroxidation, nitric oxide levels and malondialdehyde levels. Our findings showed that CREL infusion triggered immediate high plasma lipid peroxidation and augmented TRAP, while PTX caused immediate TRAP consumption and metahemoglobin formation. Pronounced oxidative effects were detected 24h after infusion, when CREL treatment enhanced RBC counts and plasma lipid peroxidation, increased catalase activity, and decreased TRAP levels. On the other hand, after 24h, PTX-infused rats showed reduced catalase activity and reduced metahemoglobin levels. These data indicate the existence of a continuous oxidative stress generation during CREL-PTX treatment and highlight CREL as primarily responsible for the in vivo oxidative damage to RBCs.

Immunological effects of Taxol and Adryamicin in breast cancer patients

Antineoplastic chemotherapy still consists in the major first-line therapeutics against cancer. Several reports have described the immunomodulatory effects of these drugs based on in vitro treatment, but no previous data are known about these effects in patients and its association with immunological-mediated toxicity. In this study, we first characterize the immunological profile of advanced breast cancer patients treated with doxorubicin and paclitaxel protocols, immediately after chemotherapy infusion. Our findings included an immediate plasmatic reduction in IL-1, IL-10, and TNF-α levels in doxorubicin-treated patients, as well as high levels of IL-10 in paclitaxel patients. Further, it was demonstrated that both drugs led to leukocytes oxidative burst impairment. In vitro analysis was performed exposing healthy blood to both chemotherapics in the same concentration and time of exposition of patients, resulting in low IL-10 and high IL-1β in doxorubicin exposition, as low TNF-α and high IL-1 in paclitaxel treatment. Nitric oxide levels were not altered in both in vivo and in vitro treatments. In conclusion, our data revealed for the first time that the immediate effects of chemotherapy could be mediated by cytokines signaling in patients and that the results observed in patients could be a resultant of host immune cells activation.

Antioxidant Capacity of the Leaf Extract Obtained from Arrabidaea chica Cultivated in Southern Brazil

Arrabidaea chica leaf extract has been used by people as an anti-inflammatory and astringent agent as well as a remedy for intestinal colic, diarrhea, leucorrhea, anemia, and leukemia. A. chica is known to be a good producer of phenolics. Therefore, in the present study, we investigated its antioxidant activity. The phenolic composition of A. chica leaves was studied by liquid chromatography coupled to diode array detection (LC–DAD) and liquid chromatography coupled to electrospray ionization-tandem mass spectrometry (LC–ESI-MS/MS), and isoscutellarein, 6-hydroxyluteolin, hispidulin, scutellarein, luteolin, and apigenin were identified. The extract from leaves of A. chica was tested for antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, β-carotene bleaching test, and total reactive antioxidant potential (TRAP) method. The crude extract quenched DPPH free radicals in a dose-dependent manner, and the IC50 of the extract was 13.51 µg/mL. The β-carotene bleaching test showed that the addition of the A. chica extract in different concentrations (200 and 500 µg/mL) prevented the bleaching of β-carotene at different degrees (51.2% ±3.38% and 94% ±4.61%, respectively). The TRAP test showed dose-dependent correlation between the increasing concentrations of A. chica extract (0.1, 0.5, and 1.0 µg/mL) and the TRAP values obtained by trolox (hydro-soluble vitamin E) 0.4738±0.0466, 1.981±0.1603, and 6.877±1.445 µM, respectively. The 2 main flavonoids, scutellarein and apigenin, were separated, and their antioxidant activity was found to be the same as that of the plant extract. These 2 flavonoids were quantified in the plant extract by using a validated HPLC-UV method. The results of these tests showed that the extract of A. chica had a significant antioxidant activity, which could be attributed to the presence of the mixture of flavonoids in the plant extract, with the main contribution of scutellarein and apigenin.

Nitric oxide is responsible for oxidative skin injury and modulation of cell proliferation after 24 hours of UVB exposures

Abstract Nitric oxide (NO) is produced by various mammalian cells and plays a variety of regulatory roles in normal physiology and in pathological processes. This article provides evidence regarding the participation of NO in UVB-induced skin lesions and in the modulation of skin cell proliferation following UVB skin irradiation. Hairless mice were subjected to UVB irradiation for 3 hours and the skin evaluated immediately, 6 and 24 hours postirradiation. The skin lipid peroxidation, and NO levels evaluated by chemiluminescence and inducible nitric oxide synthase (iNOS) and nitrotyrosine immunolabelling increased significantly 24 hours after irradiation and decreased under the treatment with aminoguanidine (AG). On the other hand, cell proliferation markers, PCNA and VEGF showed a strong labelling index when AG was used. The data indicate that NO mediates, at least in part, the lipid peroxidation and protein nitration and also promotes the down regulation of factors involved in cell proliferation. This work shows that the NO plays an important role in the oxidative stress damage and on modulation of cell proliferation pathways in UVB irradiated skin.

Oxidative and proteolytic profiles of the right and left heart in a model of cancer-induced cardiac cachexia

Cardiac cachexia is a syndrome that has received increased attention in recent years. Although an association between proteolysis and cardiac cachexia has been proposed, the direct influence of oxidative stress on the process has not been demonstrated. In the present study, the right (RH) and left (LH) hearts (atrium and ventricle of each side of the heart) were collected from rats at the 5th and 10th days after phosphate buffer (control) orWalker-256 solid tumour implantation. Immediately after sacrifice, cachexia was determined in tumour-bearing animals by the formula: [(inicial body weight-final body weight+tumour weight+weight gain of control group)/(initial body weight+body mass gain of control group)]×100%; RH and LH were stored until use. Oxidative stress and proteolysis were determined in each collected sample. In addition, heart samples were collected from a separate set of animals to determine the thickness of the left and right ventricles. Cachexia values increased over time after tumour implantation from 6.85% at the 5th day to 17.76% at the 10th day. There was no significant difference in LH wet weight and ventricle thickness compared with the control, where as RH wet weight (0.109±0.09g at the 5th day and 0.093±0.09g at the 10th day) and thickness (420±16μm at the 5th day and 279±08μm at the 10th day) were significantly decreased at both time points when compared with control values (0.153±0.06g and 607±21μm, respectively). tert-Butyl-stimulated chemiluminescence analysis revealed a significant increase in the LH and decrease in the RH oxidative stress profiles. Carbonylated proteins increased in the LH (140%, p<0.05) and RH (100%, p<0.05) at the 5th day, and significantly decreased in both sides on the 10th day compared to controls. Chemotrypsin-like, caspase-like, and calpain-like activities were evaluated by chemiluminescence, and only calpain-like activity was found to increase at the 5th day in the RH. In the LH, all proteolytic activities systems were decreased when compared with controls. Together, these results demonstrate that oxidative stress appears to play a different role in mass modulation on the LH and RH. The proteolytic systems evaluated herein also appear to have different effects on the responses developed during cardiac cachexia in the two sides of the heart.