Approaches and Methods to Measure Oxidative Stress in Clinical Samples: Research Applications in the Cancer Field

Abstract

Reactive oxygen species (ROS) are common by-products of normal aerobic cellular metabolism and play important physiological roles in intracellular cell signaling and homeostasis. The human body is equipped with antioxidant systems to regulate the levels of these free radicals and maintain proper physiological function. However, a condition known as oxidative stress (OS) occurs, when ROS overwhelm the body’s ability to readily detoxify them. Excessive amounts of free radicals generated under OS conditions cause oxidative damage to proteins, lipids, and nucleic acids, severely compromising cell health and contributing to disease development, including cancer. Biomarkers of OS can therefore be exploited as important tools in the assessment of disease status in humans. In the present review, we discuss different approaches used for the evaluation of OS in clinical samples. The described methods are limited in their ability to reflect on OS only partially, revealing the need of more integrative approaches examining both pro- and antioxidant reactions with higher sensitivity to physiological/pathological alternations. We also provide an overview of recent findings of OS in patients with different types of cancer. Identification of OS biomarkers in clinical samples of cancer patients and defining their roles in carcinogenesis hold great promise in promoting the development of targeted therapeutic approaches and diagnostic strategies assessing disease status. However, considerable data variability across laboratories makes it difficult to draw general conclusions on the significance of these OS biomarkers. To our knowledge, no adequate comparison has yet been performed between different biomarkers and the methodologies used to measure them, making it difficult to conduct a meta-analysis of findings from different groups. A critical evaluation and adaptation of proposed methodologies available in the literature should therefore be undertaken, to enable the investigators to choose the most suitable procedure for each chosen biomarker.

Hyperoxia Alters Ultrastructure and Induces Apoptosis in Leukemia Cell Lines

“…There is, to our best knowledge, no reliable way to measure intracellular antioxidant status. Surrogates are possible, but only partially reflect oxidative stress, and biomarkers have a wide variability [63].…”

Tender Coconut Water Inhibits the Process of Lipid Peroxidation, Reduce Glucose Levels and Increase Plasma Insulin in Pregnant Diabetic Rats

“…25 Vitamin E (α-tocopherol) is a lipid-soluble vitamin which acts as a lipid peroxyl radical scavenger, preventing lipid peroxidation chain reactions in the cell membranes. 26 Arginine supplementation has been shown to be a promising method of improving cardiovascular function type II diabetes by increasing endothelial NO synthesis. 11 Tender coconut water contains L-arginine.…”

A Highly Sensitive Fluorogenic Assay for the Detection of Nephrotoxin-Induced Oxidative Stress in Live Cells and Renal Tissue

“…Since these stable modified biomolecules are formed promptly after chemical injury, they can serve as a biomarker for identifying potential cytotoxins. Carbonylation is commonly detected using alpha-effect amines as reporter molecules in biochemical assays [7,8]. The conventional assays often require lengthy tedious downstream processing and harsh chemical components that can alter subcellular structures, thereby misrepresenting spatial distribution of carbonylated biomolecules [9].…”