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The Alzheimer’s & Stroke Connection

The Alzheimer’s & Stroke Connection

A stroke is also referred to as a cerebrovascular accident, in which blood flow is interrupted leading to brain damage. Interestingly, there have been several studies that seek to determine the relationship between Alzheimer’s and/or Dementia, neurodegenerative diseases, with stroke, a vascular disease. Researchers are beginning to make the connection between vascular contributions to cognitive impairment, such as stroke-induced brain damage, and cognitive diseases such as dementia and Alzheimer’s. Interestingly, almost half of all people with Alzheimer’s have evidence of strokes in their brains.

How Alzheimer’s Affects The Brain

As we age, it is normal for our brains to shrink slightly but they don’t lose neurons in large numbers. When an individual has Alzheimer’s, a domino effect occurs in the brain; neurons stop functioning properly, neural connections and pathways are slowly lost, and, eventually, these neurons begin to die in large numbers. The progression of Alzheimer’s disrupts the processes of neural communication, metabolism, and repair.

In the beginning stages of the disease, it attacks the parts of the brain involved in memory, like the hippocampus and entorhinal cortex. As the disease progresses, it affects more important areas like the cerebral cortex, which is responsible for language, reasoning, and social behavior. Eventually, Alzheimer’s damages many other areas of the brain; over time, the affected individual gradually loses their ability to live and function independently. Ultimately, this disease will result in death, as the brain loses all integral functions like respiration, swallowing, and metabolic processes.

Characteristics of a Brain With Alzheimer’s

Many chemical and cellular changes occur in the brain of someone with Alzheimer’s; while they happen over time, the results are far from mild. These changes can not only be observed in the brain post-mortem, but also in the individual’s behavior while they are living with the disease. Healthy brains contain large molecules called amyloid precursor proteins, which regulate synapse formation, neural plasticity, and iron export. However, in the Alzheimer’s brain, this naturally-occurring protein is cleaved into a smaller form called beta-amyloid. This broken-down protein is thought to be directly responsible for the onset of the disease. Researchers have identified several forms of beta-amyloid within the Alzheimer’s brain; one of them, beta-amyloid 42, is known to be especially toxic. The Alzheimer’s brain contains abnormally high levels of these beta-amyloid proteins, which clump together to form plaques that can be seen piling up between neurons. These blockages disrupt neural communication and cell function.

Healthy neurons are internally supported by structures called microtubules, which guide the transport of molecules within the cell. A protein called tau binds to the microtubules and stabilizes them. However, in a brain with Alzheimer’s, tau abnormally accumulates within neurons, forming neurofibrillary tangles. As a result of abnormal chemical changes in a brain with Alzheimer’s, tau detaches from microtubules and sticks to each other, forming threads. Eventually, these tangles block the neuron’s transport system, damaging communication between cells.

The Link Between Alzheimer’s & Stroke

At this point in time, we know that certain drugs and lifestyle interventions can prevent cerebrovascular disease. It is a known fact that cardiovascular (heart) diseases, diabetes, high blood pressure/cholesterol, inactivity, and poor diet are risk factors for stroke. However, it’s been hinted that these risk factors may be connected to Alzheimer’s as well. Researchers do not know for certain whether the improved control of vascular risk factors can be translated to decrease dementia risk, but results from a number of studies suggest that it is possible. By minimizing your risk for stroke, you may be minimizing your risk for Alzheimer’s or dementia as well.

When these plaques and tangles are combined, the likelihood of being diagnosed with dementia or Alzheimer’s is significantly higher. In fact, researchers have determined that Alzheimer’s disease plays a key role in hemorrhagic stroke. A buildup of amyloid is the main culprit behind brain hemorrhage in elderly people. In addition, the immune system response to blood flow in the brain in the progression of Alzheimer’s disease is different than in a normal brain. A healthy brain consists of glial cells, called microglia, which engulf and destroy waste and toxins to help keep the brain free of debris. However, in a brain with Alzheimer’s, microglia don’t clean up all the protein clusters, tangles, and other wastes. These microglia collect around the neurons but fail to do their job; as a result, they release chemicals that cause chronic inflammation and further damage the cells they are trying to protect.

Implications 

According to the research, Alzheimer’s causes strokes but strokes can also worsen Alzheimer’s symptoms; thus, these two diseases are intimately related. The best practice is to follow preventive measures to curb the onset of Alzheimer’s in stroke survivors, to prevent stroke in Alzheimer’s patients, and to avoid both diseases entirely in healthy individuals. Aside from these co-morbid chemical changes, studies have shown a strong relationship between sleep deprivation and Alzheimer’s disease. Sleep is known to clear away beta-amyloid clusters in the brain; therefore, sleep deprivation causes larger amounts of this toxic molecule to buildup between neurons.

If you or a loved one have suffered an ischemic stroke, learn more about CBC Health’s revolutionary stem cell stroke treatment. Check out our frequently asked questions or call us today at (855) 602-3265.

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