Cause of Alzheimers: The Unknown Answer

In the United States, approximately 5.3 million people suffer from this debilitating disease. Alzheimer"s is the most common cause of dementia. Dementia is the progressive decline in congnitive function. The brain cells die over time, and people gradually lose their ability to function and live independently. In the end stages, the personality can change too.

Alzheimer's is characterized by plaques and tangles in the brain. Plaques are an accumulation of amyloid protien between the nerve cells while tangles are a deposit of tau protien that accumulate in the nerve cells.

The standard explanation of Alzheimer's is called the amyloid hypothesis. In this hypothesis, toxic protien fragments, called peptide amyloid beta, accumulate in the brain and become a sticky plaque.The plaques are abnormal clumps of brain cells. These plaques disrupt normal brain function. Although plaques cause the symptoms of Alzheimer's, scientists are not sure what causes the plaques. Some theories on what causes these plaques are:

• Myelin model - Myelin covers our nerve axons and allows the efficient conduction of nerve impulses. However, over time, myelin needs to repair itself. Peptide amyloid beta and tau peptide which cause the sticky plaques responsible for Alzheimer's are by-products of this repair process. Through adulthood, the myelin coats an increasing number of axons with smaller axon diamenters. As we age, the body isn't able to sustain repairing the myelin sheaths, and the sheaths become thinner and thinner. Eventually, it breaks down faster than it can be repaired, and they become more susceptible to damage Furthermore, the repair process produces the peptides which cause the plaque.
• Genetics - Some studies have linked a gene to late-onset Alzheimer's. Called APOE 4, forty percent of people who develop early-onset Alzheimer's carry this gene. In 2007, scientists found another gene linked ot Alzheimers called SORL1.
• Viral infection - Researchers have found the cold sore virus or Herpes Simplex Virus I i(HSV I) is a major cause of the insoluble protien plaques in the brains of people with Alzheimers. Once infected with the HSV I, it lives in the peripheral nerves for life. Researchers found that the herpes virus is located in the amyloid plaques. In fact, 90% of the amyloid plaques in Alzheimer's patients contain HSV I DNA. Consequently, antivial drugs or vaccinations may help the plaques in Alzheimers from developing or progressing.
• Bacteria - The bacterium called Chlamydia Pneumoniae may increase the risk of developing Alzheimer's as well as heart disease and hardening of the arteries.
• Age - There are two types of Alzheirmer's; early-onset and late-onset. Most people develop late-onset Alzheimers which usually develops after 60 years of age. Alzheimer's develops in 5% of people over 65, but by the time they reach 80, it affects 20%. Some people can develop it as early as their 30s, but only 5% to 10% develop it before 65 years of age.
• Gender - It occurs more frequently in women because they live longer. There also appear to be differences in the personality changes of the disease. Whereas men seem to become more aggressive, wander more, and act inappropriately in social settings; women seem to become more reclusive, refuse help, and display inappropriate emotions.
• A malfunction of the immune system and a protien imbalance in the brain -The immune system uses macrophages to clean amyloid-beta waste products from the brain. However, if there is a defect in the immune system, it can allow amyloid-beta waste products to build up and form plaques.
• Aluminum - There is circumstantial evidence linking aluminum to Alzheimer's but no causal relationship has been established yet. One research study found traces of aluminum in the brains of Alzheimer's patients, but studies since then have either been questionable or unable to confirm the finding. Consequently, it is controversial.
• Nitrates - Researchers at Rhode Island Hospital have found a substantial link between nitrates in the environment and food and deaths from alzheimer's, diabetes, and Parkinson's disease.
• Insulin resistance Although the reason is on not completely understood, there is a connection between diabetes and insulin resistance. Diabetes was already connected to vascular dementia because of the blood vessel damage that can occur. However, now researchers believe those who have diabetes have a higher risk for Alzheimer's regardless of the vascular damage. Scientists believe peripheral insulin resistance cause toxic lipids to cross blood-brain barrier and damage the brain. Studies with inhaled insulin have shown improvement in memory and attention spans in those with Alzheimer's.
• Sleep apnea - A strong connection exists between sleep apnea and Alzheimer's. Using a CPAP (continuous positive airwaly pressure) machine can improve cognitive functioning in those with Alzheimer's and sleep apnea.

From this research, it appears to me that anything that damages the brain may increase the risk of Alzheimers or worsen the symptoms of Alzheimer's.

Alzheimer's is a tragic disease. The slow progression and loss of congnitive functioning rob people of being able to live independently, live a quality life, and remember their loved ones. However, by living a healthy lifestyle, maybe people can help prevent it.