Oxidative shielding or oxidative stress?

Robert K Naviaux1

  • 1University of California San Diego School of Medicine, 214 Dickinson St., Bldg CTF, Rm C102, San Diego, CA 92103-8467, USA. naviaux@ucsd.edu

Insights

Reactive oxygen species (ROS) are a response to disease, not the cause. Chronic oxidative changes are part of an evolved "oxidative shielding" defense, suggesting therapies should target metabolic conditions, not ROS.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Immunology

Background:

  • Oxidative damage biology has long focused on reactive oxygen species (ROS) as a cause of chronic disease.
  • Chronic oxidative changes in lipids and proteins are observed in numerous diseases.

Purpose of the Study:

  • To challenge the conventional view of oxidative damage in disease.
  • To propose that oxidative changes are part of an evolved protective response called "oxidative shielding."

Main Methods:

  • Review of existing evidence on oxidative stress and cellular responses.
  • Analysis of the evolutionary origins of oxidative shielding from innate immunity pathways.

Main Results:

  • Evidence suggests oxidative shielding, not ROS, is a primary response to hostile environments.
  • Metabolic and functional defects precede ROS increase, indicating ROS are a consequence, not cause.
  • Oxidative shielding is triggered by both oxidative and reductive stress.

Conclusions:

  • Reactive oxygen species (ROS) and associated oxidative changes are a response to disease, not its cause.
  • Therapeutic strategies should target the underlying metabolic conditions that trigger oxidative shielding, not the shielding response itself.
  • Redirecting research to identify triggers of oxidative shielding is crucial for human health.

Related Concept Videos

Oxygen Requirements and Growth Patterns01:29

Oxygen Requirements and Growth Patterns

Microorganisms exhibit diverse oxygen requirements and growth patterns driven by their metabolic strategies and environmental adaptations. Oxygen, while essential for many organisms, can also be toxic under certain conditions, shaping how microorganisms grow and survive.Oxygen Requirements of MicroorganismsMicroorganisms are classified based on their ability to use or tolerate oxygen:● Obligate aerobes like Mycobacterium tuberculosis need oxygen for energy production, as it serves as the...
Radical Autoxidation01:20

Radical Autoxidation

The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form hydroperoxide. Autoxidation involves initiation, propagation, and termination steps. Many organic compounds are susceptible to autoxidation—especially ethers in the presence of oxygen, which form hydroperoxides. Even though this reaction is slow, old ether bottles contain small amounts of peroxide, which leads to laboratory explosions during ether...
Oxidation of Phenols to Quinones01:17

Oxidation of Phenols to Quinones

In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen.
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
Electron Transport Chain: Complex III and IV01:43

Electron Transport Chain: Complex III and IV

During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
Aging01:26

Aging

Aging is a complex biological phenomenon influenced by various processes that affect cellular and systemic functions. Several prominent theories attempt to explain its mechanisms, highlighting cellular limitations, oxidative damage, and hormonal changes as central factors in aging.
Cellular Clock Theory
The cellular clock theory posits that the human lifespan is closely tied to the finite capacity of cells to divide, a phenomenon governed by telomeres, which are protective caps at the ends of...
Bioactivation and Tissue Toxicity01:25

Bioactivation and Tissue Toxicity

Bioactivation is a metabolic process that transforms less reactive substances into highly reactive metabolites, initiating tissue toxicity. This transformation can lead to various toxic effects, including carcinogenesis and teratogenesis. Reactive metabolites are classified into two main types: electrophiles and free radicals.Electrophiles are electron-deficient species and are produced primarily by the enzyme cytochrome P-450 during the metabolism of compounds containing carbon, nitrogen, or...