VII. Neurodegenrative diseases
Neurodegeneration is defined as health conditions of the progressive loss of structure or function of neurons, including death of neurons, including Parkinson’s, Alzheimer’s, and Huntington’s diseases due to genetic mutations, most of which are located in completely unrelated genes.
Common types of neurodegenrative diseases affected by free radicals
A. Alzheimer’s disease
B. Parkinson’s disease
C. Down`s syndrome
D. Amyotrophic lateral sclerosis (ALS)
E. Ischemia/reperfusion injury
F. Mitochondrial DNA disorder
G. Multiple sclerosis
A. Alzheimer’s disease
Alzheimer's disease is defined as a health condition of an irreversible, progressive brain disease that slowly destroys memory and thinking skills, and eventually even the ability to carry out the simplest activity, due to the loss of neurons and synapses in the cerebral cortex and certain subcortical regions.
Early Alzheimer’s disease signs and symptoms
a. Loss of memory
b. Amnestic mild cognitive impairment
Mild Alzheimer’s disease symptoms
a. Getting lost
b. Trouble handling money
c. Paying bills
d. Taking longer to complete normal daily tasks
f. Repeating question
g. Poor judgment, and small
h. Mood and personality change
Moderate Alzheimer’s Disease
a. Loss of language control,
b. Loss of reasoning,
c. Loss of sensory processing, and
d. Loss of conscious thought.
e. Memory loss and
g. People begin to have problems recognizing family and friend
Severe Alzheimer’s Disease
People with severe Alzheimer’s cannot communicate and are completely dependent on others for their care.
2. Risk factors
Age is the most important risk factor. As we age, beside our body's ability to repair itself becomes less efficient, but also the accumulation of plague over the years has started affecting the functions of the brain due to cell death. The brain has reached the stage for the disease to occur. Over 1 in 20 Canadians over age 65 is affected by Alzheimer's disease.
b. Family history and Genetics
Although it happens to (5-7%) of the patience, but family history of certain genes mutation has caused the development of abnormal characteristics which associated with early onset Alzheimer's disease or Alzheimer's disease.
c. ApoE4 Gene
This gene is the most important genetic risk factor for the sporadic form of Alzheimer's disease. Since the ApoE genes regulate the production of a protein that helps carry cholesterol, but the inherited ApoE4 gene is associated with the high risk of the development of Alzheimer's disease.
d. Female Gender
Twice as many women get Alzheimer's disease than men, it may be due to female live longer than male. Other suggested that it is due to decline of production of estrogen and hormone replacement therapy.
e. Cardiovascular Disease
High blood pressure and cholesterol levels can contributed to plague building up in the brain cells. Strokes and mini-strokes can increase the risk of oxidation of the brain cells.
f. Oxidative stress
Oxidative stress is a significant cause in the formation of the disease.
g. Down Syndrome
People with trisomy 21 (Down Syndrome) have an extra gene copy which exhibits Alzheimer's disease by 40 years of age.
3. Free radicals and Alzheimer’s disease
Free radicals causes Alzheimer’s disease is well defined in many researches. In a study of protein oxidation in the brain in Alzheimer's disease by using immunohistochemistry and two-dimensional fingerprinting of oxidatively modified proteins (two-dimensional Oxyblot) together to investigate protein carbonyl formation in the Alzheimer's disease brain, researchers found that oxidative stress-induced injury may involve the selective modification of different intracellular proteins may lead to the neurofibrillary degeneration of neurons in the brain. (source)
4. Antioxidants and Alzheimer’s disease
a. Docosahexaenoic acid (DHA)
Researchers found that DHA increases phosphatidylserine, a naturally occurring component found in every cell membrane of the body and improves the memory of animals with Alzheimer's disease by suppressing oxidative damage in the brain.
b. Vitamin E
In a study, researcher found that vitamin E, and drugs that reduce generalized inflammation, may slow the decline of mental and physical abilities in people with Alzheimer's disease (AD) over the long term. Also vitamin E inhibits cells damage and cells death caused by beta-amyloid, which is toxic to brain cells.
In one double-blind, placebo-controlled study, patients who had Alzheimer’s disease who took 300 milligrams per day (mg/day) of phosphatidylserine scored significantly better on standardized memory tests at the end of the 12-week trial period than patients who received placebo.
Antioxidant are found at much lower levels for patients with Alzheimer’s disease, such as serum of vitamin A, C, E, zinc and transfferin.
e. Muscarinic cholinergic receptors
researchers found that Alzheimer’s disease patients exhibit the significant loss of muscarinic cholinergic receptors neurons that cause the reduced volume of neural transmission leading to the loss of memory.