Stem Cell Therapy for Cerebral Ischemia
Stem Cell Therapy for Cerebral Ischemia. Vessels of the Brain and Causes of Stroke

Chances are good that you are at least familiar with the term "cerebral ischemia" even if you are not completely certain what it means. Most people equate it with stroke. However, while there is a direct relationship, cerebral ischemia is not stroke. It is actually the condition that leads to a stroke, or cerebral infarction.

While cerebral ischemia does not always lead to stroke, that is one of the most common outcomes. According to the American Heart Association and the American Stroke Association, almost 800,000 people in the US suffer a stroke each year. Most strokes (75%) are first-time events, and stroke is actually the fifth leading cause of death in the country, with 130,000 deaths per year. Stroke is also a leading cause of long-term disability. 87% of all strokes are ischemic strokes, as well.

What Is Cerebral Ischemia?

Cerebral ischemia is a really just a condition in the brain in which blood flow is reduced. This is due to a blockage in a vessel or artery. As a result of this blockage, the amount of blood to a specific area of the brain becomes too low to support metabolic processes, and this results in cutting off of oxygen to that area of the brain. Eventually, the tissue dies. The death of the tissue is ischemic stroke, but the cause of stroke is cerebral ischemia. If blood flow could be improved, the tissue would not develop hypoxia, and it would not die.

There are actually two types of cerebral ischemia. The first is called focal ischemia. In this situation, the blood flow to a very particular area of the brain is limited. The second is called global ischemia and it involves reduction of blood flow to larger areas of the brain. Both types can lead to cerebral infarction/stroke, though.

Symptoms of Cerebral Ischemia

It is important to understand the symptoms of cerebral ischemia, as the sufferer’s life may depend on getting help immediately. Some of the most common symptoms of cerebral ischemia onset include:

  • Slurred speech
  • Difficulty understanding other people
  • Severe, rapid-onset headaches often accompanied by vomiting and dizziness
  • Blacking out
  • Difficulty moving parts of the body
  • Weakness or numbness in the body
  • Unable to feel portions of the body
  • Unconsciousness
  • Blindness

Note that in most cases, cerebral ischemia leads to a stroke. However, it can also lead to heart attacks, as well as to permanent brain damage.

What Causes Cerebral Ischemia?

The underlying cause of cerebral ischemia is a blockage that prevents blood flow from reaching portions of the brain, thereby starving those areas of oxygen and creating a condition called hypoxia. The blockage can be a clot, or plaque buildup in the neck or inside the skull, but it can also be a condition that stops the flow of blood completely, such as a heart attack.

Ultimately, cerebral ischemia is a result of a circulatory disease, and can even be caused by narrowing of the arteries that supply blood to the brain, even if blood flow is not cut off completely. Individuals suffering from sickle cell anemia, congenital heart defects, clotting disorders, high blood pressure, atherosclerosis and high cholesterol are all at increased risk for cerebral ischemia and ischemic stroke. Diabetics, smokers, those who are overweight, and heavy drinkers are also at increased risk.

Treatment Options for Cerebral Ischemia

The most common treatment option for cerebral ischemia and ischemic stroke is the use of tissue plasminogen activator, or tPA, to break up clots and restore blood flow to the brain. However, time is of the essence here, because tPA cannot be administered to a patient more than five hours after the onset of symptoms. In some instances, surgical removal of the clots will be necessary. If cerebral ischemia was caused by high blood pressure rather than a clot, a stent may be needed to reduce blood pressure and increase blood flow.

What Is the Role of Stem Cell Therapy in Treating Cerebral Ischemia?

Stem cells are currently being investigated for use in helping patients recover from ischemic stroke, and even for preventing cerebral ischemia in the first place. One study published in the journal Comp Neurology noted that,

"Exogenous stem cells from multiple sources can generate neural cells that survive and form synaptic connections after transplantation in the stroke-injured brain. Stem cells from multiple sources also exhibit neuroprotective properties that may ameliorate stroke deficits."

Another study, this one published in the Journal of Cerebral Blood Flow and Metabolism noted,

"Bone marrow stem cells can be mobilized by granulocyte-colony stimulating factor for homing into the brain for both neurorepair and neuro-regeneration in acute stroke and neurodegenerative diseases in both basic science and clinical settings."

In order to understand the role of stem cells, one must develop insight into their function within the body. Stem cells are the precursors to all other types of cells. They are present when the embryo first begins to develop, and they remain present in the body throughout life, although they do decline in number and functionality over time. Stem cells have many jobs, but their primary one is to transform themselves into any type of tissue necessary in order to repair damage. For instance, pancreatic stem cells can transform into damaged beta islet cells.

The challenge with stem cells is that the body’s own cells are often not enough to effect repair in disease situations. This is because stem cells accumulate mutations and damage over time, reducing their ability to heal, as well as their ability to divide (limiting their lifespan). This makes the use of autologous stem cells (a patient’s own cells) in treating diseases insufficient.

Instead, allogeneic stem cells sourced from umbilical cord blood and tissue can be used. Allogeneic stem cells have no accumulated damage, and have a lifetime of division and healing remaining to them. They are also completely immune-naïve, so there is no fear about evoking an immune system response.

In Conclusion

One day, stem cells could hold the key to healing the damage caused by cerebral ischemia and ischemic stroke, or even preventing the condition completely. However, at the time of this writing, there are no FDA-approved stem cell treatments available. Any such treatments should be considered experimental only.

Source:

Stem cell therapy for cerebral ischemia: from basic science to clinical applications
Potential of Stem Cell-Based Therapy for Ischemic Stroke
Stem Cells for Ischemic Brain Injury: A Critical Review
Stem cell therapy for cerebral ischemia: from basic science to clinical applications
About Cerebral Ischemia
What are the symptoms of ischemia in the brain?
Epidemiology and Risk Factors of Cerebral Ischemia and Ischemic Heart Diseases: Similarities and Differences/

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