Oxidative stress , Pathological Physiology course

1. Fadi Marroushi
Pathological Physiology
UPJS – Kosice
2015-2016

2. Definition
A disturbance in the balance between reactive oxygen
species (ROS) and antioxidants.
Under normal conditions, cells are able to balance the
production of oxidants and antioxidants.
Oxidative stress occurs when there is imbalance in our
cells due to either an increase in free radicals and/or a
decrease in antioxidants.

3. What are ROS ?
 Chemically reactive molecules containing oxygen.
 Natural byproduct.
 Increased levels causes damage.
 Exogenous sources.

4. Endogenous Production of ROS

5. Oxidative Phosphorylation
Electrons are passed through the complexes and reach
their final destination, an oxygen molecule, then the
oxygen is reduced to produce water.
However, sometimes oxygen is incompletely reduced to
give superoxide radical (·O₂ˉ).
Superoxide can inactive specific enzymes or initiate lipid
peroxidation in its protonated form Hydroperoxyl
(HO₂·)

6. Exogenous Production of ROS
 Diet
 Exercise
 Alcohol
 Smoking
 Air / Water pollution
 Stress
 Ionizing radiation
 Lack of sleep

8. ROS and RNS
Reactive Oxygen Species
(ROS)
Symbol Reactive Nitrogen Species
(RNS)
Symbol
Hydroxyl OH· Nitric Oxide NO·
Superoxide ·O₂ˉ Nitric Dioxide NO₂·
Hydrogen Peroxide H₂O₂ Peroxynitrate OONOˉ
Peroxyl RO₂· Nitroxyl Anion NOˉ
Singlet Oxygen ˉ¹O₂ Dinitrogen Trioxide N₂O₃
Hypochloric Acid HOCl Nitrous Acid HNO₂
Ozone O₃

9. Antioxidants
 Not really a substance, but a behavior.
 Chemicals
 Inhibit oxidation of other molecules.
 Specific

11. Antioxidant-Rich Food
 Berries and cherries
 Citrus (Oranges, Grapefruit..)
 Pomes (Apples, Pears…)
 Honey
 Dark Chocolate
 Herbs
 Spices
 Nuts

13. Antioxidants-Rich Beverages
 Green tea
 Natural juices
 Red wine

14. Endogenous Antioxidants
 Vitamins
Vitamin A (-caroten), Vitamin C, Vitamin E, Vitamin K
 Minerals
Zinc, Selenium
 Amino Acids
Glutathione (GSH), Methionine, N-Acetyl Cysteine
 Enzymes
Coenzyme Q10 (CoQ10), Superoxide Dismutase (SOD),
Glutathione Peroxidase (GPx), NAD+

15. Common diseases caused by oxidative stress
Damage to biomolecules like Lipids, Proteins, DNA, will eventually
lead to diseases like:
 Atherosclerosis
 Cancer
 Diabetes
 Rheumatoid arthritis
 Myocardial infarction
 Cardiovascular diseases
 Chronic inflammation

16. References
 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC27246
65/
 https://en.wikipedia.org/wiki/Oxidative_stress
 http://www.amazing-glutathione.com/what-are-
antioxidants.html
 http://www.wallerwellness.com/what-is-functional-
medicine/understanding-oxidative-stress
 http://study.com/academy/lesson/what-is-oxidation-
definition-process-examples.html