Stress: A Possible Trigger for Atherosclerosis

Summary

In Stress: Portrait of a Killer a documentary by National Geographic goes in depth about how dangerous stress can be. For humans stress is always present. There is always a worry about work, finances, relationships, and other situations that poses a challenge. In most mammals stress is a few minutes of terror in a in a habitat full of predators. Biologist want to understand why humans, apes, and monkeys get more stress related diseases. They have concluded that humans and their primate cousins are highly intelligent with too much time to spare. It seems that humans and primates have evolved to be very intelligent to make themselves sick. Robert Sapolsky is a biological science professor who was spent more than 30 years studying the physiological effects of stress on health.

During stress response all vertebrates release hormones which increase the animals heart rate and energy level. Stress is something that cannot be controlled. Constantly worrying about finances, work, or other situations trigger the release of adrenaline and other stress hormones. Over time stress can cause devastating consequences to health. In the video they also discussed some of the stress related diseases such as diabetes, high blood pressure, and a bunch of gastrointestinal disorders. Long term stress conquers the immune system making it vulnerable to infectious diseases. Being chronically stressed also affects brain function. Controlling stress is crucial to being healthy. Sapolsky advices tho try whatever to reduce stress to avoid any stress related disease. In class we briefly discussed atherosclerosis. A disease that can be caused by stress. High levels of cortisol receptors from long term stress can increase blood sugar, cholesterol, and blood pressure. This stress can build up plaque and deposit it in the arteries.

Description of the Disease

In the United States, heart disease is one of the leading causes of death. Millions of people suffer from this horrible disease. Heart attacks and strokes are caused by a common disorder known as atherosclerosis. Atherosclerosis takes place when plaque begins to build up in the artery walls. Fats, cholesterol, calcium, waste product from cells, and fibrin is what composes the plaque. If not treated this disease can be life threatening. Heart attacks and strokes can occur when the plaque begins to form and slowly blocking arteries causing the cut off of blood supply to the heart or the brain. Not only are strokes and heart attacks the most common condition, atherosclerosis is also in charge of other fatal diseases such as peripheral disease, and chronic kidney disease.

Etiology

The entire body contains many blood vessels called arteries. The arteries are very important because they are in charge of transferring blood from the heart to the entire body. The endothelium is the thin layer of cells that line the arteries. The endothelium keeps the inside of the arteries nice and smooth to keep good blood flow. The buildup of plaque begins when the endothelium is damaged by high blood pressure, high cholesterol and smoking. The entry of cholesterol in the wall of the artery happens when bad cholesterol goes through damaged endothelium, causing white blood cells to stream in digesting the bad cholesterol. The cholesterol and cells transform into plaque in the cell wall of the artery over time. Slowly the plaque begins to pile up creating bumps within the artery wall. If atherosclerosis is left untreated the bumps will continue the build up process creating a blockage.

This may occur anywhere in the body. Atherosclerosis causes the heart to be at risk for potential attacks as well for strokes and many other health issues. When atherosclerosis begins, it usually does not present any symptoms until middle or older ages. When arteries begin to narrow down, it will cut off blood flow and create pain. Blockages can also burst causing the blood to clot inside an artery. The plaque that forms in the arteries can act in many different ways. Plaque can remain in the artery wall. It can reach a certain amount and stop its growth. This plaque does not block blood flow therefore there may be no symptoms. Plaque may also grow at a very slow rate. Over time it will cause blockage. Pain will surface in the chest or legs during exercise. The worst thing that can happen is rupturing a plaque. A ruptured plaque allows blood to clot and lead to a stroke or a heart attack. There are three main types of cardiovascular disease. The three main diseases are cerebrovascular disease, peripheral disease, and coronary artery disease. Cerebrovascular disease happens when ruptured plaques in the brain's arteries cause strokes leaving permanent brain damage. Transient ischemic attacks are caused by temporary blockages in an artery. These are warnings of a stroke. In this case there is no brain injury. In peripheral disease, the arteries located at the legs are narrowed by plaque and can cause weak circulation. This will cause pain during walking and wounds do not heal very well. If the buildup of plaque is severe, amputation may be necessary. During coronary artery disease, the stable plaques in the heart may cause chest pains. If a plaque were to rupture it would clot and cause heart muscles to die, this is known as a heart attack.

Risk Factors of Atherosclerosis

There are many risk factors of atherosclerosis. Not exercising enough will cause someone to gain weight. As a person gains weight, they will have a higher chance of developing atherosclerosis. If they manage to lose the weight, their chances become smaller. Having high levels of LDL cholesterol, also known as bad cholesterol will also increase the risk of having atherosclerosis. Plaque is the mixture of LDL cholesterol, fats, calcium and white blood cells that will build up inside the walls of the arteries. In more severe cases, the blood flow can be completely blocked. (Atherosclerosis 2019). Old age is also a risk factor because plaque in the arteries have been gathered up longer and have had more time to do damage. A person’s lifestyle is one of the most important factors because it determines what type of diet they have. Genetics also play a role due to the fact that some people have a higher chance of having weaker arteries. (Risk Factors 2019)

People are more likely to develop atherosclerosis if they have high blood pressure because high blood pressure adds force to the artery walls. With time, the added force will damage the arteries making them thinner and weaker.

Smoking can cause damage and constriction to blood vessels. It can raise cholesterol levels, and also raise blood pressure. It also affects oxygen levels by not allowing it to reach the body’s tissues. The toxins in tobacco smoke lower the high-density lipoprotein cholesterol (HDL). This is considered the good cholesterol. Toxins will also raise LDL levels which is the bad cholesterol. The nicotine and carbon monoxide will damage the vessel, more specifically the endothelium, making it much easier for plaque to settle. (Smoking and your heart 2019)

There are also other new risk factors for atherosclerosis that scientists continue to study. Having a high level of a protein called C- reactive protein (CRP) has been found to have a significant relation to heart disease. Since CRP is present in atherosclerotic lesions, it may contribute to the progression of the progression and instability of the atherosclerotic plaque. Another emerging risk factor is having high levels of triglycerides in the blood. Researches suggest that targeting triglycerides may be an effective strategy. However, how triglycerides relate to the disease is still undetermined. (New Study 2016)

Mechanism of the Disease

Even though we still don’t know the exact mechanism of atherosclerosis, some evidence has been found that in some people the condition can begins in childhood with the formation of tiny streaks of fat deposition in the arteries. For some people, it will progress rapidly in their 30’s. For other people, it doesn’t manifest until they reach age 50-60.

As the endothelium becomes more infiltrated by the fatty materials- primarily LDLs, macrophages, which are immune cells will travel to the site to look for the materials. The macrophages will be filled with lipids, they will be called foam cells which will die and gather up in the endothelial lining. Other materials such as: salts, calcium, smooth muscle cells will also gather up in the lining. This will take a toll on the lining and cause lesions. Atheromas, also known as atherosclerotic plaques will form. In addition, these plaques will make the vessel thinner, interfering with the flow of blood. If there is an injury to the endothelium because of the lipids damaging the vessels or as a result of another cause, there may be a formation of fibrous caps of scar tissue. (Atherosclerosis 2019) The vessel walls will become less elastic in the areas of scar tissue. The flow of blood will decrease in the vascular beds due to the thick plaques that damage the arteries. In addition, the endothelium will be compromised and there may be a formation of a thrombus, or blood clot at the site of a plaque. It may then cause an obstruction in the channel or can even break free from the site and cause a block somewhere else. (Atherosclerosis 2019)

Signs and Symptoms of Atherosclerosis

Atherosclerosis isn’t usually diagnosed until the person complains of chest pain. This is because there is no way to know until the artery is so narrowed or damaged that it can’t supply enough blood to the organs and tissues. A blood clot may also cause a block in blood flow, or even break apart and trigger a heart attack or stroke. The symptoms of moderate to severe atherosclerosis will depend on the area of the body where those arteries have been affected.

When atherosclerosis reached the heart arteries, people may have symptoms of chest pain or pressure. Another word for chest pain is angina. If there is atherosclerosis in the arteries in the brain, people will experience different signs and symptoms. These people could experience numbness or weakness in the arms or legs, as well as difficulty speaking or slurred speech. They may also temporarily lose vision in one eye. Another sign is drooping in the face muscles. These are signs of a transient ischemic attack (TIA). If a TIA is left untreated, it may turn into a stroke. Atherosclerosis in the arms or legs can also be signs of something called peripheral artery disease. Someone with peripheral artery disease leg pain when walking. Finally, when there is atherosclerosis in the arteries leading to the kidneys, it may lead to high blood pressure and even more serious, kidney failure. (Arteriosclerosis/Atherosclerosis 2019)

Secondary Complications

One secondary complication that occurs when having atherosclerosis is high serum lipid levels. With the enhancement of LDL uptake by monocytes and macrophages, atherosclerotic lesions are initiated (Choy 2004). LDL stands for low density lipoprotein. LDL cholesterol can be bad and lead to clogged arteries (Choy 2004). If a person has an LDL level that is too high, plaque can form on the walls of the cardiovascular system, which then blocks the flow of blood to the heart and leads to a heart attack or stroke (Choy 2004). Another secondary complication a person may have if they experience atherosclerosis is aneurysms. When a person has an aneurysm, they experience a bulge in the wall of their artery. People do experience pain and throbbing when they have an aneurysm. If an aneurysm would burst, a person could face life threatening internal bleeding.

Secondary complications like aneurysms, occur by destruction of mural architecture and concomitant loss of tensile strength attributable to bioengineering fatigue. Since atherosclerosis accelerates the breakdown of collagen and elastin, which is bad because they provide support to the wall of the aorta. As time passes, the walls of the aorta become fragile and damaged. The aortic wall then expands and forms a bulge due to elevated blood pressure through the aorta. This is the cause of how an aneurysm occurs. The last secondary complication is chronic kidney disease. Cardiovascular complications caused by an atherosclerosis disease correspond with patients with chronic kidney disease (Olechnowicz-Tietz 2013). These patients provide many atherosclerotic risk factors, some traditional, as well as some nontraditional risk factors such as inflammation and oxidative stress. Chronic kidney disease occurs when a person’s kidneys are damaged and prevent filtering of blood (Olechnowicz-Tietz 2013). When patients have an impaired renal function, they are at a higher risk for cardiovascular complications. Atherosclerosis disease impairs renal function, thus, leading to all these secondary complications.

Prognosis

Atherosclerosis is a disease that can be slowed down or destroyed, but if left untreated it progresses and the bump on the artery wall enlarges. If this bulge gets big enough, it creates a blockage. This makes not only a person’s heart at risk, but also puts them at risk for a stroke and other health complications. Also, when plaque builds up and ruptures this also causes threats for a heart attack and stroke.

Prevention/Treatment

A person can do a lot in or order to prevent the disease of atherosclerosis. Atherosclerosis is a disease that a person has a lot of control over. A person can prevent this from occurring by avoiding smoking, being overweight, having high cholesterol, and having high blood pressure (Holloway). When a person smokes, they damage the artery walls, which can ultimately lead to atherosclerosis (Holloway). When the artery walls are damaged, it is easier for plaque to build up. When a person has a high cholesterol, plaque can also build up on the lining of artery walls and narrow their arteries (Holloway). Exercise can help with lowering cholesterol and blood pressure. If lifestyle changes such as exercising and dieting doesn’t workout, a person can also take medication. Treatment for atherosclerosis include variety of medication that help lower your blood pressure and blood sugar levels, prevent blood clots, and prevent inflammation. Doctors can also prescribe statins that help people that have diabetes or high LDL cholesterol levels. If a person has severe atherosclerosis, they may even have to get surgery. For example, there is a procedure called coronary angioplasty, it is used to open blocked or narrowed coronary arteries. This procedure can also relieve chest pain by improving the blood flow to the heart. This disease will be hard to eliminate considering how many people that smoke a day and live an unhealthy lifestyle.