Role of free radical in the development of atherosclerosis

Jan S. PurbaDepart. Neurologi. FK UI/RSCM

Jakarta

Oxidation causes body damage

Don’t let rust attack you

What is free radical

• Free radicals are very unstable compounds, without the proper number of electrons, and they tend to react quickly with neighboring compounds, trying to "steal" electrons from other molecules in an attempt to regain stability,

• If they succeed, then the "victim" atom or molecule usually loses its electron balance and becomes a free radical itself,

• In fact, even if the free radical is not able to steal the electron, it may still create such a pull as to disrupt the workings of neighboring atoms and molecules.

• This can start a chain reaction; and once the process is started, it can build exponentially.

The source of free radicals

• Mitochondria (major) source of free radicals• Tumor Necrosis Factor−alpha (TNF−α) stimulates free radical

production by mitochondria. • Ultraviolet light (UV) produces free radicals. • Neutrophils use oxidative free radicals (superoxide, hydrogen

peroxide, hydroxyl) to kill bacteria in associated with inflammation. • The lysosomal enzyme myeloperoxidase catalyzes the

production of bacteriocidal hypochlorite from hydrogen peroxide and chloride ions.

• Generated by eicosanoids from arachidonic acid during ischemia-reperfusion injuries.

• Tobacco smoke and air pollution can cause oxidative damage to lungs, blood vessels and other body tissues

Normal metabolism in Physiological Condition

Mitochondria

Endogen Antioxidant

BALANCEFree Radical

General Free radical Actions

• Free radical damage to LDL cholesterol leads to atherosclerosis,

• Similarly, free radicals have been implicated in cancer, Alzheimer's Disease, inflammatory diseases, ischemic-reperfusion injury

• Between one and five percent of the oxygen used by mitochondria to generate energy results in the formation of superoxide radicals

EXPERIMENTAL BIOLOGY AND MEDICINE; Wei, YH; 227:671-682 (2002)

Atherosclerosis

• Atherosclerosis is a disease affecting arterial blood vessels

• It is a chronic inflammatory response in the walls of arteries, in large part due to the accumulation of macrophage white blood cells and promoted by low density lipoproteins (LDL)

• It is caused by the formation of multiple plaques within the arteries

• It is commonly referred to as a "hardening" or "furring" of the arteries

Physiologic factors that increase risk for atherosclerosis

• Advanced age• Having Diabetes or Impaired glucose tolerance (IGT)• Dyslipoproteinemia (unhealthy patterns of serum proteins carrying fats &

cholesterol): – High serum concentration of low-density lipoprotein (LDL), and / or very

low density lipoprotein (VLDL) particles, – Low serum concentration of functioning high density lipoprotein (HDL) – An LDL:HDL ratio greater than 3:1

• Male sex • Tobacco smoking • Having high blood pressure • Being obese (in particular central obesity)• Having close relatives who have had some complication of atherosclerosis

(eg. coronary heart disease or stroke) • Elevated serum levels of triglycerides, homocysteine, uric acid, fibrinogen

concentrations,• Stress or symptoms of clinical depression • Hyperthyroidism

LDL and atherosclerotic

• Normal LDL in plasma is not oxidized. • Oxidation of LDL is believed to contribute to the

development of atherosclerosis • Macrophage cells preferentially take up oxidized LDL,

become loaded with lipids, and convert into "foam cells" (Aviram 1996)

• Foam cells accumulate in fatty streaks, early signs of atherosclerosis

• Humans produce auto-antibodies against oxidized LDL, and the levels of such auto-antibodies are higher in patients with atherosclerosis

Adhesion of monocytes onto endothelial cells and their foamy

change

Severe atherosclerosis of the aorta

Microphotography of arterial wall with calcified (violet colour) atherosclerotic plaque (haematoxillin & eosin stain)

Light micrograph of a fibrofatty plaque in the coronary artery. FC = fibrous cap; MP = myeloproliferative; C = cap are calcifiedF= healed fissure; A = adventitia is the outermost area of the artery [From Gravanis MB. Histopathology of atherosclerosis. In: Atlas of Atherosclerosis: Risk Factors and Treatment, edited by Wilson PWF. Philadelphia, PA: Current Medicine, 2002.]

Antioxidants

Definition

Antioxidants are chemical compounds that can bind to free oxygen radicals preventing these radicals from damaging healthy cells

• Antioksidan Endogen (antioksidan yang dihasilkan oleh tubuh)

• Enzim:– SOD– GPx– Katalase

• Non Enzim– Albumin– Bilirubin– Melantonin– Co. enzim –q– As. Urat

• Antioksidan Eksogen (antioksidan yang di dapat dari luar)

• Vitamin:– Vit. C, E, A,

karotenoid,

• Zat lain – NAC– Lycopene– Fenol– Mineral, selenium

Antioksidan

Superoxide dismutase (SOD) as a therapeutical use

• Superoxide dismutase (SOD) has proven therapeutically useful in protecting injured tissues from one of these active oxygen species, the superoxide radical.

• The ability of SOD to protect tissues against any particular insult (ischemia, inflammation, hyperoxia, etc.) depends on several parameters such as :

- its rate of plasma clearance, - ability to equilibrate between extracellular fluid compartments,- and the ability to closely approach negatively charged cell

surfaces . • Other enzymes that are part of the cell's arsenal against these

active oxygen species include catalase and glutathione peroxidase, which eliminate H2O2.

Superoxide dismutase (SOD)

• Living cells produce reactive oxygen species (ROSs).

• To protect themselves from these ROSs, the cells have developed both an antioxidant system containing superoxide dismutase 1 (SOD1) and a redox system including peroxiredoxin2 (Prx2, thioredoxin peroxidase) and glutathione peroxidase1 (GPx1)

ENZYMES AS ANTI-OXIDANTS and DETOXICANTS IN CELLS

• Catalase is a heme protein that catalyzes the reaction shown below in which hydrogen peroxide is detoxified.

• It is usually found in peroxisomes except in cells like erythrocytes that do not contain these organelles (in that case catalase is a cytoplasmic enzyme).

• Catalase provides a protective role that is similar to that of glutathione peroxidase because both are important means of removing hydrogen peroxide.

• Both catalase and glutathione peroxidase are important in hydrogen peroxide detoxification.

• Catalase

2 H2O2 O2 + 2 H2O

ENZYMES AS ANTI-OXIDANTS and DETOXICANTS IN CELLS

• Glutathione peroxidase is a cytoplasmic and mitochondrial enzyme that is important for detoxifying H2O2 in most cells.

• This protein is a seleno protein, i.e., it contains a selenocysteine amino acid at the active site instead of a normal cysteine.

• The selenium that replaces the normal sulfur in this amino acid has enhanced nucleophillic properties and ionizes more readily to release a proton.

• It is a much more effective catalyst in the reaction catalyzed by this enzyme.

H2O2 + 2 glutathione (GSH) glutathione disulfide (GSSG) + H2O

Superoxide dismutases (SODs)

• Superoxide dismutases (SODs) are a class of closely related enzymes that catalyse the breakdown of the superoxide anion into oxygen and hydrogen peroxide

• SOD enzymes are present in almost all aerobic cells and in extracellular fluids

Enzymatic pathway for detoxification of reactive

oxygen species

Under normal conditions, ROS are cleared from the cell by the action of superoxide dismutase (SOD), catalase, or glutathione (GSH) peroxidase. The main damage to cells results from the ROS-induced alteration of macromolecules such as polyunsaturated fatty acids in membrane lipids, essential proteins, and DNA.

GLISODIN®

GLISODIN®

Antioxidant Enzymes

• GliSODin™ (Superoxide dismutase)/gliadin is a unique vegetarian source of highly absorbable SOD that works synergistically with the body's own naturally occurring SOD to prevent the oxidative effects of the superoxide radical.

• GliSODin™ is the first S.O.D. shown to increase the body's own S.O.D. levels by oral ingestion.

• S.O.D, also known as the master antioxidant, is the body's number 1 free radical fighter.

• Select antioxidant enzymes have been added including GliSODin™, the only orally effective form of SOD.

• Also powerful hydrogen ions that scavenge many types of free radicals

GLISODIN®

FARMAKOLOGI• SOD merupakan zat penetral radikal bebas

tahap paling awal.• Glisodin mengandung SOD dikombinasikan

dengan gliadin SOD tidak dipecah di lambung.

• Gliadin akan meningkatkan translokasi SOD di usus.

• Suplemantasi Glisodin meningkatkan SOD internal, GPx dan Katalase.

• Glisodin juga mempunyai potensi antiinflamasi.

Under normal conditions, ROS are cleared from the cell by the action of superoxide dismutase (SOD), catalase, or glutathione (GSH) peroxidase. The main damage to cells results from the ROS-induced alteration of macromolecules such as polyunsaturated fatty acids in membrane lipids, essential proteins, and DNA.

Antioxidants and immune system

• Antioxidants are notable for boosting the immune system because immune system cells in the bloodstream are so easily accessed by free radicals as well as by antioxidants.

• Cells of the immune system (like T-Cells, B-Cells and Macrophages) have membranes that are particularly rich in long-chain unsaturated fatty acids (such as arachidonic acid or EPA).

• For this reason (and also because of their mobility and functions) immune system cells are more vulnerable to free radical oxidation than other cells.

• The nutrients that most profoundly improve immune function are Vitamin C, Vitamin E, selenium, glutathione and zinc 

SOD

IntestineIntestine

M cells

SOD/GliadinSOD/Gliadin

Intestinal SOD/Gliadin (GliSODin®) transport and pharmacology:

Phase 2:Initial Immune Contact & Activation

Phase 3:Gearing-up whole body immune response

Phase 1:Digestive absorption}}

Optimizing the whole body

cellulardefense system

From 3 to 8 weeks of treatment

•cellular uptake of SOD/Gliadin (GliSODin)

(GliSODin)®

• production of cellular

antioxidants

•Antigen processing

• cytokine production

Phase I

Macrophages andepithelial cells

Macrophages andepithelial cells

I. Natural Immunity

Dendriticcells

Dendriticcells

• antigen presentation

•T cell activation

•Th1 polarization(IFN- etc.)

•Antibody production

Phase II

Th1 B

T cellsT cells B cellsB cells

II. Specific Immunity

SOD/Gliadin (GliSODin®) : Mechanism of Action

Antioxidant

mobilization

Phase III

Red blood cellsRed blood cells

and tissues and tissues

III. Tissular defenses

GLISODIN®

INDIKASI Penggunaan jangka pendek, Glisodin sebagai

suplemen antioksidan

Penggunaan jangka panjang, untuk menunjang sistim kekebalan tubuh terhadap radikal bebas

GLISODIN®

DOSIS dan CARA PEMBERIAN:• Jangka pendek: Glisodin empat siklus

pemberian/ tahun; 2 kapsul (500 mg)/ hari saat makan pagi selama 4 – 6 bulan (sebulan penuh 1 bulan istirahat sebulan penuh demikian seterusnya).

• Penggunaan harian (jangka panjang): satu kapsul (250 mg) setiap hari saat makan pagi.

PERINGATAN dan PERHATIAN Sebaiknya tidak diberikan pada orang yang alergi

terhadap gluten karena mengandung “wheat protein”.

KEAMANAN Tidak didapatkan toksisitas akut maupun kronik pada

pemberian selama 28 hari Glisodin 2000 mg/ kgBB/ hari. Tidak didapatkan perubahan fisik maupun histologi

(jaringan) setelah penggunaan tersebut.

EFEK SAMPING Glisodin dapat ditoleransi dengan baik, belum pernah

dilaporkan efek samping serius selama pemberian glisodin .

GLISODIN®