The Cycle of Life

Every organism that comes into existence goes through a cycle which begins with birth, continues through development, and always ends with death. Regardless of the organism, it seems that aging and death has been largely determined by genetics and the genetic alterations that occur within a life-span. According to the Brain Research Centre, several biochemical pathways are involved in the aging process, which “include those that govern DNA repair, control the death and survival of individual cells in a process called apoptosis, control the functions of mitochondria in cells, regulate the organism’s response to oxidative stress, and govern metabolic consequences of glucose intake.”

Our genetic coding is important in regulating metabolic functions, controlling what genes are expressed, determining cell death, and managing other functions within the body. Of these functions, cell death plays a major role in aging. For people older than 60, it has been found that those with shorter telomeres have are three times more likely to die from heart disease and eight times more likely to die from infectious disease.

One major change that occurs in the body during aging is the cell death, and scientists have hypothesized that cell death, or apoptosis, is controlled by telomeres. Telomeres are repetitive sequences at the ends of chromosomal DNA that help protect the chromosome from deterioration. During cell division, the enzymes that duplicate the DNA are unable to copy the DNA all the way to the end; therefore, cell replication always causes a shortening of DNA. Once the DNA is shortened to a certain degree, the cell can no longer divide and can lead to cell death, or apoptosis. Apoptosis is programmed to prevent further replication of any damaged DNA in order to ensure that cell replication is done accurately (inaccurately replicating DNA can cause abnormal tumor growth and cancer).

Because DNA replication results in a chromosomal shortening, an enzyme known as telomerase utilizes the mechanism of reverse transcriptase to lengthen the repetitive ends and protect the chromosome from damage. Some research has also been done to see whether or not telomerase activity could “immortalize” human cells and extend human life. Dr. Richard Cawthon, a researcher at the University of Utah’s School of Medicine, did a study and confirmed that people with longer telomeres lived five years longer than people with shorter telomeres and believes that the human lifespan can be extended by ten to thirty years if telomere shortening was completely stopped. Cawthon’s study proves that exercise and a healthy lifestyle are not the only factors that can affect life span but that genetic factors play a major role in the average life expectancy.

Resources:

1. http://learn.genetics.utah.edu/content/begin/traits/telomeres/

2. http://www.brain.ubc.ca/TheAgingBrain.php

3. http://www.scientificamerican.com/article.cfm?id=anti-aging-pill-targets-telomeres

Sweet Tooth or Sweet Brain?

As we all know, an uncontrolled diet high in sugars and fats can have noticeable effects on weight, provide insufficient nutrients for the body, and increase the risk of diabetes. However, few people realize that rising glucose levels in the body may also affect the function of vital organs, such as the pancreas and, especially, the brain.

Approximately 120 grams of glucose are needed by the brain in a single day, most of which is generated via gluconeogenesis from non-sugar molecules within the body. Although glucose is a necessary component for the normal functioning of the brain, it has also been proven that an excess could cause damage to the brain itself and decrease cognitive decline. According to a study conducted by Dr. Scott A. Small, associate professor of neurology in the Sergievsky Center and in the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain at Columbia University Medical Center, glucose specifically targets the dentate gyrus within the hippocampus, decreasing activity in that region of the brain. Because high blood glucose levels damage the part of the brain that controls memory and learning, which suggests that it may play a major role in Alzheimer’s disease and dementia.

Since the brain is constantly firing neurons, it requires about two times more glucose than other cells within the body. However, neurons cannot store glucose, so they depend on the bloodstream to deliver a constant supply glucose to fuel the brain. Because of this, physical exercise, which helps reduce blood glucose level, can help to lower glucose levels in the dentate gyrus and enhance cognitive function. Once again, it seems pretty obvious that exercise plays a huge role in the process of aging—physically and mentally.

Resources:

1. http://www.washingtonpost.com/wp-dyn/content/article/2008/12/30/AR2008123000993.html

2. http://www.cumc.columbia.edu/news/press_releases/081230_Aging.html

3. http://brainfuels.com/2010/03/toxic-glycolysis-and-brain-aging/

One Fish, Two Fish, Omega-3 Fish Oil

Up to this point, I have only mentioned that eating well, exercising, and keeping the brain actively engaged are the main ways to keep your brain healthy. However, there are also supplements that can be consumed to prevent diseases, such as Alzheimer’s and dementia, and repair brain damage by promoting neuronal growth. One of the most beneficial supplements to take to lower mental decline is omega-3 fish oil.

Omega 3-fish oil is a supplement that is known to prevent cancer and cardiovascular disease, boost immune function, decrease inflammation, and, most importantly, slow down the rate of mental decline. The supplement includes the polyunsaturated omega-3 fatty acids α-linolenic acid, eicosapentaenoic acid (EPA), which decreases inflammation and has beneficial potential in mental conditions, and docosahexaenoic (DHA), which is derived from EPA. It may also raise levels of an enzyme that protects brain cells from plaque buildup and provide a good supply of DHA which allows for better transport of brain signals.

In a 6-year study by Dr. Martha Clare Morris, 3718 individuals of 65 years and older were analyzed for cognitive change, according to the amount of fish intake in an individual’s diet. According to her study, the rate of mental decline was reduced by 10% for individuals who consumed fish one or more times a week and 13% for individuals who consumed fish two or more times a week. Similarly, the April 2007 Journal of Neuroscience published a study that was done on mice that were genetically modified to have an accumulation of amyloid and tau proteins in the brain. In mice that received a balanced diet of a 1 to 1 ratio of omega-6 and omega-3, there was less accumulation of beta amyloid and tau proteins. From one of my previous blogs, I mentioned that Alzheimer’s disease resulted from a buildup of plaque, which is caused by an accumulation of amyloid and tau proteins. Thus, scientists have concluded that omega-3 fish oil is associated with Alzheimer’s disease.

Nutrition is a life-long preventative measure that is not a quick fix. Therefore, in order to get the most out of the benefits of omega-3 fish oil, it is important to make sure that you are consuming enough of it as soon as possible. You can design your diet to integrate omega-3 by eating fish oil supplements, fish, and vegetables, such as boiled cauliflower, boiled cabbage, romaine lettuce, broccoli, and even tofu.

Resources:
1. http://www.stopagingnow.com/news/news_flashes/5621/The-7-Best-Brain-Boosting-Supplements
2. http://www.aboutomega3.com/
3. http://archneur.ama-assn.org/cgi/reprint/62.12.noc50161v1.pdf
4. http://www.jneurosci.org/cgi/content/abstract/27/52/14299

Memory. Control. Now Sight??

Alzheimer’s Disease and Parkinson’s Disease are both well-known neurodegenerative disorders, one which affects memory in the hippocampus, and the other which affects muscle control from cell death in the substantia nigra. However, since the brain essentially controls everything in the body, it is important to understand other age-related changes that indirectly affect the brain’s perception, like macular degeneration, which affects vision. I know that discussing all these problems of aging on the brain seems morose, but it is definitely advantageous to discuss the effects of aging on the brain so that symptoms can be detected early on and preventative measures can be taken.

According to Marilyn Haddrill, age-related macular degeneration, also known as AMD, is the leading cause of blindness and loss of vision for Americans who are 65 years or older. In addition, because the number of people in this age group are increasing, the number of individuals facing this problem are increasing.

AMD is a degenerative disorder that results in the death of photoreceptors and supporting epithelial cells in the central part of the retina, or macula. Because of this, central vision is lost and things begin to look blurred and distorted. There are two forms of AMD: dry and wet. Dry AMD occurs usually results from thinning of macular tissues or depositing of pigment in the macula. Wet AMD is the more severe and progressive form of AMD and results from new blood vessel growth under the macula that causes scarring which leaves light-sensitive retinal cells damaged.

Treatment for AMD can slow the progress and slightly improve vision. FDA approved treatments include, Lucentis, Macugen, and photodynamic therapy. In addition, new research is being done to find more ways of treating AMD. The National Eye Institute is studying the possibility of transplanting healthy cells into the retina to take the place of dead cells and also looking into anti-inflammatory treatments for wet AMD. While aging is a risk factor of AMD, like all diseases, an unhealthy lifestyle can also increase the risk of getting AMD.

Resources:

1. http://www.allaboutvision.com/conditions/amd.htm

2. http://www.brain.ubc.ca/documents/MacularDegeneration.pdf

3. http://www.medicinenet.com/macular_degeneration_age-related_type/page8.htm#research

Serotonin: The New Dopamine

While the most common form of neurodegenerative disorder is Alzheimer’s Disease, the second most common, affecting four to six million individuals in the world, is Parkinson’s Disease (PD). While PD is generally known to be an elderly disease, the Michael J. Fox has noted that 10% of known cases occur before the age of 40. Similar to Alzheimer’s Disease, there are treatments for the symptoms, but on-going research is continued to try to find a cure for this disease.

PD occurs when a group of brain cells in the area of the brain, called the substantia nigra, fail to produce enough dopamine. Dopamine plays an important role in voluntary movement in the brain. Without the neurotransmitter, initiating and sustaining voluntary movement becomes progressively more difficult to the point where swallowing and walking may be heavily affected. When 60-80% of the brain cells in the substantia nigra die, symptoms appear as tremors.

Since dopamine plays such a crucial role in PD, scientists have previously treated PD symptoms by increasing the amount of L-DOPA, a dopamine precursor, in patients’ brains. However, patients grow a tolerance, and the demand of L-DOPA for the same results increases. Thus, many researchers have looked to other angles to try to approach the problem of PD.

Dr. Bjӧrklund and his team target the serotonin system as a possible treatment of PD. According to Dr. Bjӧrklund, “serotonin neurons are capable of converting levodopa to dopamine and can store and release newly synthesized dopamine as dopamine neurons do in a healthy brain.” Thus, the dopamine system becomes more impaired, the serotonin system can be used to assist in the making of dopamine from levodopa, providing the brain with a natural pathway for making dopamine. While clinical trials are still in progress, possibilities for cures such as the one proposed by Dr. Bjӧrklund and researchers under the Michael J. Fox Foundation for Parkinson's Disease Research provide PD patients with hope.

Resources:

1. http://www.michaeljfox.org/docs/2008_Annual_Report.pdf

2. http://www.parkinson.org/

3. http://www.brain.ubc.ca/Neurodegeneration.php#PD

Not Aged, Just Dead!

Dementia is seen in 25 percent of people over 85 years old. The most common form of dementia, Alzheimer’s disease, occurs in one in twelve individuals over 65 and one in three individuals over 80. As of now, there is no real cure to the disease, and its effects are irreversible. There are many myths surrounding the cause of Alzheimer’s disease and its treatments. However, being informed about what Alzheimer’s is will help to dispel these myths.

Alzheimer’s disease is a neurodegenerative disorder that impairs learning and memory but may even lead to impaired judgment and mood changes, which may heavily affect one’s daily life. One of the biggest myths out there is that Alzheimer’s disease occurs as a result of age; however, this is not true. There have been many cases of Alzheimer’s disease diagnosed in younger patients. In addition, Alzheimer’s is not a normal part of aging. It occurs as a result of plaque buildup in the brain that becomes toxic to brain cells once excessive levels of deposit have been reached. In addition, as the brain cells degenerate and die, the brain somewhat shrinks, which explains the results of the size difference between a brain with Alzheimer’s disease and a normal brain. Since Alzheimer’s is not a normal part of aging, many people believe that genetics is the cause of it. However, genetics may only be mildly linked to the disease (only 7% of all reported cases are related to genetic onset of Alzheimer’s).

As of now, Alzheimer’s is neither preventable nor curable, but ongoing research is being done to find out if anything can be done. Recently announced by Irish drug company Elan and Wyeth-Ayerst Laboratories, the vaccine "AN-1792" contains bits of beta-amyloid. When injected in the human arm, the vaccine stimulates the immune system's antibodies to target amyloid plaques and removes the foreign bodies. This response is hoped to clear out plaques in the brain which cause Alzheimer's disease. This theory, which has been shown to be somewhat successful in rats and safe in humans, though not completely conclusive is a promising discovery towards finding the cure to Alzheimer's Disease. There is, however, growing evidence that a healthy lifestyle can help reduce the risks of Alzheimer’s disease. Remember—treat your body well, and it will treat you well!

To learn more about Alzheimer’s disease, visit this website.

Resources:
1. http://health.asiaone.com/Health/Women%2527s%2BMatters/Story/A1Story20100218-199510.html
2. http://www.alzheimer.ca/english/disease/myths.htm
3. http://www.pbs.org/wnet/brain/episode5/alzheimers/index.html

The Chemicals Behind It All

The brain is composed of a network of over 100 billion nerve cells, or neurons, that branches out and connects in over 100 trillion places, forming a “neuron forest.” Each neuron is made up of a cell body, dendrites, and axons, which work together to pass along signals from one end of the system to the other end. Within this complex system, signals are passed on through an action potential as well as chemical signals known as neurotransmitters.

Neurotransmitters, such as dopamine and serotonin, are chemicals within the brain that send out specific signals. As an individual gets older, the brain sends out less and less neurotransmitters, which is somewhat connected to learning impairment or memory loss.

About ten years ago, the neurodegenerative disorders were connected to neural cell death. However, as mentioned in my previous post, technological advancements have helped us to understand that these disorders are associated with plaque formations in the brain. Recent research has led to the Free Radical Theory, as stated by Dr. Stuart Lipton of The Burnham Institute. Free radicals are oxygen and nitrogen related molecules that are produced as a result of metabolic pathways within the body, and an excess of free radicals lead to aggregates of misfolded proteins within the brain. For example, clusters of misfolded proteins in the brain, called Lewy bodies, are found in patients with Parkinson’s disease; plaque in patients with Alzheimer’s patients; and prions in cows with Mad Cow Disease.

What have researchers said about preventing mental impairment due to free radicals? Take antioxidants to fight the oxidizing effects of free radicals. Consuming blueberries or vitamin E and drinking green tea or red wine can help decrease free radicals within the body. However, most of these don’t work well enough to completely stave off the effects of free radicals. Thus, normal every day activities will lead to the gradual decay of the brain.

Resources:

1. http://alzheimer.ca/english/alzheimer_brain_mini_site/05.htm

2. http://www.youtube.com/watch?v=um_YRFcUVpU&feature=PlayList&p=7AE7F876F78AAF63&playnext=1&playnext_from=PL&index=9