Oxidative stress and disease

What is oxidative stress?

disturbance in the balance between the production of reactive oxygen species (free radicals) and antioxidant defenses

Has been implicated in the ageing process & many diseases e.g. atherosclerosis

Leads to

Oxidative damage to :-

-DNA

-Proteins

-Lipids (unsaturated fatty acids)

Diseases

-rheumatoid arthritis

-atherosclerosis and coronary heart disease

-cancers

-G6PD deficiency hemolytic anemia

antioxidants

Trace elements

vitaminsenzymes

SeleniumVitamin AVitamin C Vitamin E

-superoxide dismutase-catalase-glutathione system

Glutathione system

Consists of :-

Glutathione , NADPH ,reductase , peroxidase

and selenium .

N.B.

G6PD (Glucose 6-Phosphate Dehydrogenase)

Is essential for formation of NADPH which is

essential for proper function of glutathione

system.

Reactive oxygen species (ROS)

TypesFree radicals

-superoxide O2-

-hydroxyl radical OH-

-peroxyl radical ROO-

Non free radicals

-hydrogen peroxide H2O2

Sources of ROS

During course of metabolism

E.G. O2- auto-oxidation of hemoglobin and

xanthine oxidase

OH- by fenton reaction

Ingestion of toxins,chemicals and drugs

Nitric oxide NO-

Oxidative stress diseases

G6PD (hemolytic anemia)

Molecular effects of oxidative stress

-lipid peroxidation

-protein denaturation

-DNA damage

-inactivation of enzymes

-release of ca ions from intracellular stores

-cytoskeletal damage

-chemotaxis

Vascular effects

-- altered vascular tone

--increased endothelial permeability

atherosclerosis

Thank you