Oxidative stress assays

Oxidative stress is implicated in a large nuber of diseases including neurodegenerative diseases and autoimmune diseases.

Indicators of oxidative stress have been detected in muscles and blood from CFS patients. The cognitive symptoms observed in patients, could be triggered by the alteration of the blood-brain barrier’s permeability. This alteration is due to oxidative damage to cellular membranes. Increased oxidative stress in CFS patients may have several origins as chronic inflammation, excess nitric oxide production or exposuure to environmental toxins.

Oxidative stress markers are helpful to evaluate the need for antioxidant therapy.

Useful tests to that effect are:

• Total antioxidant capacity
• Fatty acids oxidation

Antioxidant systems in the body normally lilmit the extent of oxidative damage. However, a number of factors can severly affect their function.

There are many types of antioxidant systems. Although measurments of single antioxidants may be needed in some cases, the best index in oxidative stress studies is to measure the total antioxidant capacity of a sample. That measurement will show the overall effect of antioxidants working together.

Lipid peroxidation is a well-defined mechanism of cellular damage.Lipid peroxides decompose to form compounds such as malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), natural end-products of lipid peroxidation.

Measuring these end-products is ons of the most widely accepted assays for determination of oxidative damage. The capacity of MDA to interact with tiobarbituric acid (TBA) is used to quantify MDA in a serum sample. This forms a MDA-TBA adduct that can be quantified spectrophotometrically.

HIF1-alpha (HIF1A) is a subunit of HIF1, which is a transcription factor found in mammalian cells cultured under reduced oxygen tension. HIF-1 is a heterodimer consisting of an alpha and beta subunit, both belonging to the basic-helix-loop-helix Per-aryl hydrocarbon receptor nuclear translocator-Sim (PAS) family of transcription factors. HIF1 functions as a transcriptional regulator of the adaptive response to hypoxia. Under hypoxic conditions, HIF-1 activates the transcription of over 40 genes, including erythropoietin, glucose transporters, glycolytic enzymes, vascular endothelial growth factor, HILPDA, and other genes whose protein products increase oxygen delivery or facilitate metabolic adaptation to hypoxia. HIF1-alpha regulates hypoxia-mediated apoptosis, cell proliferation and tumor angiogenesis. Hypoxia which induces p53 protein accumulation, directly interacts with HIF1-alpha and reduces hypoxia-induced expression of HIF1-alpha by promoting MDM2-mediated ubiquitination and proteasomal degradation under hypoxic conditions. Recent studies suggest that induction of NOX4 by HIF1-alpha contributes to maintain ROS levels after hypoxia and hypoxia-induced proliferation. In humans, it is located on the q arm of chromosome 14. The C-terminal of HIF1A binds to p300. p300/CBP-HIF complexes participate in the induction of hypoxia-responsive genes, including VEGF. Hypoxia contributes significantly to the pathophysiology of major categories of human disease, including myocardial and cerebral ischemia, cancer, pulmonary hypertension, congenital heart disease and chronic obstructive pulmonary disease. The dysregulation and overexpression of HIF1A by either hypoxia or genetic alternations have been heavily implicated in cancer biology, as well as a number of other pathophysiologies, specifically in areas of vascularization and angiogenesis, energy metabolism, cell survival, and tumor invasion.