Thursday, April 21, 2011

II. Cardiovascular diseases - B. Ischemia

Ischemia is defined as a condition of restriction or interruption of blood supply to the body organs, as a result of plague builds up in the arteries, causing damage or dysfunction of the arterial walls.
1. Symptoms
a. Irregular or rapid pulse
b. Abnormal heart palpitations
c. Cough
d. Reduced or excessive urine output
e. Difficulty breathing when you lay down
f. Leg swelling and weight gain from heart failure
g. Weakness ,fatigue and faintness
h. Chest pain
i. Etc.

2. Risk factors
a. Tobacco
Cigarette contains high levels of cadmium, inhaling the chemical during smoking or second hamd smoke can cause building up of plaque along to the arterial walls as a result of oxidation.
b. Obesity
Obesity increases the risk of ischemia as it is normally associated with high levels of cholesterol, high blood pressure.
c. Heredity
A history of heart attack or coronary artery disease of a family, can increase the risk of ischemia to the members.
d. Hypertension
Hypertension can be inherited or bad diet with a lot of salts and aging. the disease can damage arteries that feed your heart by accelerating atherosclerosis.
e. High levels of cholesterol and triglyceride
High levels of bad cholesterols and triglyceride partial block the blood flow in the vessels, it not only increases the risk of high blood pressure but also the risk of ischemia if the blood circulation disimish.
f. Diabetes
Diabetes cause high levels of blood sugar in the blood stream which can cause the thinkening of the blood thus, reducing the blood flow to the body and increase the risk of blood being blocked.
g. Etc.

3. Free radicals and ischemia
Researcher found that free radicals generated during oxidated stress through a series of interacting pathways in cardiac myocytes and endothelial cells and triggers subsequent leukocyte chemotaxis and inflammation is greatly increased in the post-ischemic heart and serves as a critical central mechanism of post-ischemic injury.
Nitric oxide (NO), one of the antioxidant and peroxynitrite can inhibit pathways of oxygen radical generation, and, in turn, oxidants can inhibit NO synthesis from NOS.

4. Antioxidants and ischemia
a. Nitric oxide (NO)
Nitric oxide (NO), one of the antioxidant and peroxynitrite can inhibit pathways of oxygen radical generation, and, in turn, oxidants can inhibit NO synthesis from NOS.

b. glutathione and vitamin E
Reduced form of glutathione may act as a first line of defense against oxidative stress during ischemia–reperfusion while vitamin E may act later on during severe oxidative stress by rendering resistance to the heart against the ischemic–reperfusion injury

c. 2-dithiole-3-thione (D3T)
Researcher found that in rat cardiac H9c2 cells, D3T and time-dependent induction of a number of cellular antioxidants and phase 2 enzymes, including catalase, reduced glutathione (GSH), GSH peroxidase, glutathione reductase (GR), GSH S-transferase (GST), and NADH:quinone oxidoreduc- tase-1 (NQO1) help to protect against H9c2 cell injury caused by various oxidants and simulated ischemia-reperfusion. D3T pretreatment also resulted in decreased intracellular accumulation of reactive oxygen in H9c2 cells after exposure to the oxidants as well as simulated ischemia-reperfusion.

d. Selenium
Deficeiency of of a co-enzyme selenium, which is required in maintaining the glutathione redox cycle, also promote more susceptible to oxidative injure.

e. Etc.