Antioxidant status in patients with bladder cancer regarding cancer stage and grade

Objective

The imbalance of antioxidants and pro-oxidants plays a crucial role in the carcinogenesis of bladder cancer (BC). This study aimed to evaluate serum antioxidant status in patients with BC and determine its potential use in the diagnosis and progression potential considerations following histopathological assessment.

Methods

A cross-sectional study included 90 patients with BC, divided into Ta, T1, and T2-T4 stage subgroups, and according to cancer progression potential, into low-grade (LG) and high-grade (HG) subgroups. The control group (CG) included 30 healthy volunteers. Antioxidant status was determined using the spectrophotometric method and standard laboratory tests.

Results

Serum superoxide dismutase activity was significantly higher in BC patients regarding cancer stage in comparison to the CG (p<0.001). Catalase activity was highest in T2-T4 subgroup and was significantly higher compared to the Ta (p<0.01) and T1 (p<0.05) subgroups. Serum albumin level was significantly lower in the BC group compared to the CG (p<0.001). In addition, it was significantly lower in T2-T4 subgroup compared to T1 and Ta subgroups (p<0.01). A significant negative correlation was found between tumor size and serum albumin level only (r=-0.386, p<0.01). Catalase activity was higher in HG subgroup (p=0.009), while bilirubin level was higher in LG subgroup (p=0.035). The optimal cut-off value of catalase activity in differentiating patients with LG and HG BC subgroups was ≥11.96 IU/L, and the specificity and sensitivity were 51.1% and 82.2%, respectively. Bilirubin level, for a calculated optimal cut-off value of ≥11.95 μmol/L, had a specificity of 44.1% and sensitivity of 80.0%.

Conclusion

More invasive stages of BC with greater progression potential are associated with an increase in enzymatic antioxidant activity and a decrease in non-enzymatic antioxidant capacity. It may suggest a possible role of antioxidants in the prediction and monitoring of illness trajectory.

MnSOD Val16Ala gene polymorphism is associated with REDOX biomarkers in the elderly of primary health care in the city of Porto Alegre

Studies suggest that redox imbalance may be closely associated with pathological aging, contributing effectively to the genesis of several chronic diseases. One of the major defence enzymes against oxidation is Manganese-dependent superoxide dismutase (MnSOD) that acts within the mitochondria. The gene encoding this enzyme is polymorphic and Val16Ala variant is one of its most investigated polymorphisms regarding aging and oxidative stress. This study aimed to verify the occurrence of the MnSOD Val16Ala gene polymorphism association with markers of REDOX metabolism in the elderly of primary health care. A cross-sectional study was performed. The sample consisted of 270 elderly individuals from Family Health Strategy in the city of Porto Alegre, Rio Grande do Sul, Brazil (EMISUS). The following variables were investigated in all subjects: sociodemographic: gender, age, marital status, schooling and income; Anthropometric: weight, height, body mass index (BMI); REDOX markers: advanced oxidation protein products (AOPP), ischemia-modified albumin (IMA), nitric oxide metabolites (NOx), ferric reducing ability of plasma (FRAP) and malondialdehyde (MDA), MnSOD Val16Ala gene polymorphism. Val16Ala gene polymorphism was evaluated by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). Statistically significant associations were observed in the elderly with AA genotype compared to those with VV genotype, concerning AOPP (p = 0.023) and FRAP (p = 0.027) quartile frequencies, respectively. No statistically significant differences were observed between MnSOD genotypes with MDA, NOx and IMA oxidative markers. Val16Ala gene polymorphism is associated with AOPP and FRAP quartiles frequencies in the elderly of primary health care.

The expression of sirtuins, superoxide dismutase, and lipid peroxidation status in peripheral blood from patients with diabetes and hypothyroidism

BACKGROUND

Sirtuin 1 (SIRT1) and sirtuin 3 (SIRT3) proteins have an important role in counteracting oxidative stress. Although diabetes and hypothyroidism (HT) are both characterized by oxidative stress, the mechanisms are not fully understood. This study investigated the effects of type 1 diabetes (T1D), type 2 diabetes (T2D), and HT on the expression levels of SIRT1, SIRT3, and manganese superoxide dismutase (SOD2).

METHODS

Gene expression of SIRT1, SIRT3, and SOD2 was measured using real-time PCR. The protein expression of SOD2 and lipid peroxidation (thiobarbituric acid reactive substances) was measured by the TBARS Assay kit and enzyme-linked immunosorbent assay (ELISA) respectively.

RESULTS

The results showed that the SIRT1 and SIRT3 levels were lower in peripheral blood samples from patients with T1D, T2D, or HT than in healthy individuals. Interestingly, the mRNA and protein expression levels of SOD2 were higher in all three patient groups. Lipid peroxidation was higher in the patients with HT than in the healthy individuals.

CONCLUSIONS

These results indicate alterations in the expression levels of sirtuins and superoxide dismutase in diabetes and HT, which may be related, at least in part, to the oxidative stress. Identifying such alterations in those patients will pave the way towards the development of drugs to enhance SIRT1 and SIRT3 expression and their activity to prevent the damaging effect of oxidative stress.

Oxidative stress as an underlying contributor in the development of chronic complications in diabetes mellitus. Int J Mol Sci. 2013;14:3265-3284. [PMID: 23385234 PMCID: PMC3588043 DOI: 10.3390/ijms14023265]

The high prevalence of diabetes mellitus and its increasing incidence worldwide, coupled with several complications observed in its carriers, have become a public health issue of great relevance. Chronic hyperglycemia is the main feature of such a disease, being considered the responsible for the establishment of micro and macrovascular complications observed in diabetes. Several efforts have been directed in order to better comprehend the pathophysiological mechanisms involved in the course of this endocrine disease. Recently, numerous authors have suggested that excess generation of highly reactive oxygen and nitrogen species is a key component in the development of complications invoked by hyperglycemia. Overproduction and/or insufficient removal of these reactive species result in vascular dysfunction, damage to cellular proteins, membrane lipids and nucleic acids, leading different research groups to search for biomarkers which would be capable of a proper and accurate measurement of the oxidative stress (OS) in diabetic patients, especially in the presence of chronic complications. In the face of this scenario, the present review briefly addresses the role of hyperglycemia in OS, considering basic mechanisms and their effects in diabetes mellitus, describes some of the more commonly used biomarkers of oxidative/nitrosative damage and includes selected examples of studies which evaluated OS biomarkers in patients with diabetes, pointing to the relevance of such biological components in general oxidative stress status of diabetes mellitus carriers.

Polyphenols in cocoa and cocoa products: is there a link between antioxidant properties and health?

Cocoa and cocoa products have received much attention due to their significant polyphenol contents. Cocoa and cocoa products, namely cocoa liquor, cocoa powder and chocolates (milk and dark chocolates) may present varied polyphenol contents and possess different levels of antioxidant potentials. For the past ten years, at least 28 human studies have been conducted utilizing one of these cocoa products. However, questions arise on which of these products would deliver the best polyphenol contents and antioxidant effects. Moreover, the presence of methylxanthines, peptides, and minerals could synergistically enhance or reduce antioxidant properties of cocoa and cocoa products. To a greater extent, cocoa beans from different countries of origins and the methods of preparation (primary and secondary) could also partially influence the antioxidant polyphenols of cocoa products. Hence, comprehensive studies on the aforementioned factors could provide the understanding of health-promoting activities of cocoa or cocoa products components.

Effects of cocoa extract on glucometabolism, oxidative stress, and antioxidant enzymes in obese-diabetic (Ob-db) rats

In this present study, we investigated the effects of cocoa extract containing polyphenols and methylxanthines prepared from cocoa powder on the biochemical parameters of obese-diabetic (Ob-db) rats. Obese-diabetic (Ob-db) rats were developed using a high-fat diet (49% fat, 32% carbohydrate, and 19% protein from total energy, kcal) for 3 months, followed by a low dose (35 mg/kg body weight) streptozotocin (STZ) injection. Cocoa extract (600 mg/kg body weight/day) was given to the rats for 4 weeks. The results indicated that there were no significant differences in fasting plasma glucose and insulin level after 4 weeks of cocoa extract administration. Oral glucose tolerance test revealed that cocoa supplementation in Ob-db rats significantly (p < 0.05) reduced plasma glucose at 60 and 90 min compared to unsupplemented Ob-db rats. Plasma free fatty acid and oxidative stress biomarker (8-isoprostane) were significantly (p < 0.05) reduced after cocoa supplementation. Superoxide dismutase activity was enhanced in Ob-db compared to that in nonsupplemented rats. However, no change was observed in catalase activity. The results showed that cocoa supplementation had an effect on postprandial glucose control but not for long term (4 weeks). Moreover, cocoa supplementation could reduce circulating plasma free fatty acid and 8-isoprostane and may enhance the antioxidant defense system.