Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction

Summary Aim Of the many biological targets of oxidative stress, lipids are the most involved class of biomolecules. Lipid oxidation gives rise to a number of secondary products. Malondialdehyde (MDA) is the principal and most studied product of polyunsaturated fatty acid peroxidation. This aldehyde is a highly toxic molecule and should be considered as more than just a marker of lipid peroxidation. Its interaction with DNA and proteins has often been referred to as potentially mutagenic and atherogenic. This review is intended to briefly describe the physiological origin of MDA, to highlight its toxicity, describe and comment on the most recent methods of detection and discuss its occurrence and significance in pathology. Data synthesis In vivo origin as well as reactivity and consequent toxicity of MDA are reviewed. The most recent and improved procedures for the evaluation of MDA in biological fluids are described and discussed. The evidence of the occurrence of increased MDA levels in pathology is described. Conclusions In the assessment of MDA, the most common methods of detection are insufficiently sensitive and disturbed by interference coming from related species or overestimation derived from stressing analysis conditions. Moreover, no recent nutritional or medical trials report the use of one of the new and more reliable methods, some of which are undoubtedly accessible to virtually all the laboratories provided with a common HPLC or a spectrofluorimeter.

A review of recent studies on malondialdehyde as toxic molecule and biological marker of oxidative stress

Advanced oxidation protein products as a novel marker of oxidative stress in uremia

Historically, nutrition principles and recommendations for diabetes and related complications have been based on scientific evidence and diabetes knowledge when available and, when evidence was not available, on clinical experience and expert consensus. Often it has been difficult to discern the level of evidence used to construct the nutrition principles and recommendations. Furthermore, in clinical practice, many nutrition recommendations that have no scientific supporting evidence have been and are still being given to individuals with diabetes. To address these problems and to incorporate the research done in the past 8 years, this 2002 technical review provides principles and recommendations classified according to the level of evidence available. It reviews the evidence from randomized, controlled trials; cohort and case-controlled studies; and observational studies, which can also provide valuable evidence (1,2), and takes into account the number of studies that have provided consistent outcomes of support. In this review, nutrition principles are graded into four categories based on the available evidence: those with strong supporting evidence, those with some supporting evidence, those with limited supporting evidence and those based on expert consensus.

Evidence-based nutrition recommendations attempt to translate research data and clinically applicable evidence into nutrition care. However, the best available evidence must still be moderated by individual circumstances and preferences. The goal of evidence-based recommendations is to improve the quality of clinical judgments and facilitate cost-effective care by increasing the awareness of clinicians and patients with diabetes of the evidence supporting nutrition services and the strength of that evidence, both in quality and quantity.

Before 1994, the American Diabetes Association’s (ADA’s) nutrition principles and recommendations attempted to define an “ideal” nutrition prescription that would apply to everyone with diabetes (3,4,5). Although individualization was a major principle of all recommendations, it was usually done within defined …

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Evidence-Based Nutrition Principles and Recommendations for the Treatment and Prevention of Diabetes and Related Complications

Ascorbic acid: Chemistry, biology and the treatment of cancer

Plasma selenium (Se), zinc (Zn) and copper (Cu) levels and antioxidant metalloenzymes, glutathione peroxidase (GPX) and superoxide dismutase (SOD), were studied in 17 patients on maintenance hemodialysis (HD) (group I), 14 uremic patients (group II) and 14 healthy subjects (group III). Plasma Se levels and erythrocyte GPX were significantly lower in the HD group (for Se: 0.69 +/- 0.12 vs. 1.05 +/- 0.13 mumol/l in controls; for erythrocyte GPX: 34.4 +/- 6.4 vs. 49.2 +/- 9 IU/g hemoglobin in controls) and a significant correlation was found between the two parameters (r = 0.66, p less than 0.005). There was also a correlation between decreased plasma Zn and erythrocyte SOD activity (r = 0.58, p less than 0.02) and between decreased plasma Cu and erythrocyte SOD (r = 0.60, p less than 0.02). Plasma malondialdehyde levels were augmented in HD patients (5.08 +/- 0.26 vs. 2.55 +/- 0.15 mumol/l in controls and 2.79 +/- 0.40 mumol/l in the uremic group). The catalase activity was increased in HD patients (202 +/- 24 vs. 140 +/- 40 IU/mg hemoglobin in group III). A defective antioxidant activity may thus contribute to increased peroxidative damage to cells in the course of dialysis.

Trace elements and lipid peroxidation abnormalities in patients with chronic renal failure.

The general objective of the Etude du Viellissement Arterial (EVA) program is to follow vascular aging and the decline in cognitive functions at the cerebrovascular level longitudinally over a 4-year period. One of the specific objectives of this EVA study is to examine epidemiologically the relationship between the markers of oxidative stress (lipid peroxidation), the antioxidant micronutrient status (particularly of selenium, vitamin E, and the carotenoids) and the prevalence of chronic disorders occurring during the pre-aging period.1389 subjects aged from 59 to 71 years were studied.The concentration of plasma lipid peroxides was higher than in young adults (2.91 +/− 0.38, men; 2.97 +/− 0.40, women (mumol/l). On the other hand, plasma Se (1.09 +/− 0.21, men; 1.10 +/− 0.19, women (mumol/l)), erythrocyte vitamin E (5.32 +/− 1.29, men; 5.52 +/− 1.28, women (mumol/l)), and total plasma carotenoids (2.19 +/− 0.98, men; 3.07 +/− 1.33, women (mumol/l)) were comparable to values in young adults. In our cohort...

Lipid peroxidation level and antioxidant micronutrient status in a pre-aging population; correlation with chronic disease prevalence in a French epidemiological study (Nantes, France).

Selenium, glutathione peroxidase (GSH-Px) and lipid peroxidation products before and after selenium supplementation.

Lipid peroxidation is known to accelerate aging and microvascular lesions in diabetic patients. We studied the acute influence of improved glycemic control on the concentrations of plasma lipid peroxidation intermediates [malondialdehydes (MDA), organic hydroperoxides (OHP)] in ketotic insulin-dependent diabetic patients, as well as the interplay of enzymes such as glutathione peroxidase (GPX) and CuZn superoxide dismutase (CuZn-SOD), and trace elements (Zn, Se, Cu) postulated to be involved in free radical protection. These plasma components were measured on the first day of hospitalization (T0) and when the patient had attained a stable glycemic state after continuous insulin treatment (T1). Plasma MDA and OHP concentrations were high at the beginning of the study but approached reference values after glycemic equilibration. Plasma zinc concentrations were significantly (P < 0.05) decreased during the ketotic state, but also approached reference values with glycemic equilibration. Plasma selenium concentrations and GPX activity were relatively unchanged between T0 and T1. Erythrocyte GPX activity measured at T1 in six patients was below the reference values, whereas CuZn-SOD activity was not affected. Our results show that enhanced lipid peroxidation is associated with decreased zinc plasma concentrations in ketotic patients and underline the beneficial effects of continuous insulin infusion. The mechanisms involved are still unclear but may indicate the importance of extracellular zinc transfer secondary to glycemic disorders.

Lipid peroxidation and trace element status in diabetic ketotic patients: influence of insulin therapy.

The purpose of the study was to assess the actual dietary intakes of zinc (Zn), copper (Cu) and selenium (Se) intakes in relation with some indicators of trace element status in a selected group of hospitalized elderly patients.24 elderly women aged 76-99 years were recruited in the Geriatric Department of the Grenoble University Hospital.Zn, Cu, and Se dietary intakes were estimated by duplicate portion analysis. Plasma trace element concentrations, Cu-Zn superoxide dismutase (Cu-Zn SOD) and Se glutathione peroxidase (Se GSH-Px) activities were determined in parallel.Mean daily intakes of Zn (5.6 mg), Cu (0.67 mg), and Se (23 micrograms) were low, in relation with poor energy intake and nutrient densities. Zn and Se levels in plasma were lower and plasma Cu increased compared to reference values obtained from healthy younger subjects. Thirty-eight percent of the elderly patients had plasma Zn concentrations < 10.7 mumol/l, but Cu status appeared adequate as suggested by the lack of decline in Cu-Zn SOD a...

Analyzed dietary intakes, plasma concentrations of zinc, copper, and selenium, and related antioxidant enzyme activities in hospitalized elderly women.

J. Arnaud

Papers

Trace elements and lipid peroxidation abnormalities in patients with chronic renal failure.

Lipid peroxidation level and antioxidant micronutrient status in a pre-aging population; correlation with chronic disease prevalence in a French epidemiological study (Nantes, France).

Selenium, glutathione peroxidase (GSH-Px) and lipid peroxidation products before and after selenium supplementation.

Lipid peroxidation and trace element status in diabetic ketotic patients: influence of insulin therapy.

Analyzed dietary intakes, plasma concentrations of zinc, copper, and selenium, and related antioxidant enzyme activities in hospitalized elderly women.