Prevention of Stroke(Part 2)

Prevention 

Have medical check-up regularly

Even if you have not been experiencing a medical problem in the last few months or years, it is necessary that you see your physician for medical check-up. In this process, one of the things that he will evaluate is the condition of your heart. He could listen to your heart sounds, and he could find out if you have the so-called atrial fibrillation (AF). If he suspects that you have AF, he will request for electrocardiogram (ECG) test, and it will confirm if you really have the said problem. If so, your physician will either give you medicine to control your AF, or he will refer you to a cardiologist. There is a need to control your AF because, as mentioned in the preceding, it could cause stroke due to cerebral embolism.

Have your blood pressure checked regularly

As mentioned in the preceding, your blood vessels in the brain are so thin that they cannot withstand high blood pressure. Thus, it is necessary that you must check your blood pressure regularly. If elevated and above the normal values, you need to take some medications. During your medical check-up, bring up the matter to your physician for proper and necessary prescriptions. You need to control your blood pressure at all times to avoid having stroke due to ruptured blood vessel in the brain.

Have annual evaluation of your blood chemistry

In your medical check-up, one of the important things that your physician will request you to do is to have blood chemistry examination. The basic components of this test are: fasting blood sugar, blood urea nitrogen, blood creatinine, aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood uric acid, and the lipid profile test which determines the levels of your cholesterol, triglycerides, high-density lipoprotein, and low-density lipoproteincholesterol. Under the topic of preventing stroke, however, the most important  components of blood chemistry that you need to pay attention to are the fasting blood sugar and the lipid profile. If you have a family history of diabetes mellitus, you should know the level of your fasting blood sugar annually, and keep track of the trend. If it increases every year, then you need to alter and modify your lifestyle, such as your diet and your daily physical exercises.Under the lipid profile test, you should know the level of your blood cholesterol; and if it is elevated, consult your physician for dietary advice and prescription(s) of necessary drugs.

Refrain from smoking

Cigarette smokinghas been scientifically established as the root cause of several medical problems, such as cancer in the lungs. In relation to stroke, however, it has been established, too, that it accelerates the development of the so-called atherosclerosis, which is the deposition of fatty substances along the inner lining of your blood vessels. Consequently, you will develop hypertension which could lead to stroke. If you have not started smoking yet, never start doing it. If you have been smoking, stop the habit as soon as possible.

Refrain from taking high-salt and high-fat diet

If youtake meals and foodsrich in salt, or sodium, your blood pressure will rise up—much more if you are over 40 years old. Thus, before you take any food item, especially the packed ones, look at the sodium content listed on the pack.  If it is greater than 7%, avoid taking that food(s). If you have been eating in a restaurant, then you find that a certain recipe is high in salt, stop taking that food! Your blood pressure may also rise up if you take  foods rich in fats. Hence, avoid them.

(To be continued)

Prevention of Stroke (Part 1)

Definition

Your brain needs a lot of oxygen and nutrients being carried by your blood, and your blood reaches it through a network of blood vessels which  serve as its passageways.  When one of these passageways is blocked, thereby preventing the arrival of blood in a certain area of yourbrain, stroke takes place. Deprivation of blood is not the only cause of stroke. When a particular blood vessel in your brain ruptures, and the blood goes into its substance,  this is also called stroke.

Types of stroke

Due to cerebral thrombosis

Your blood vessels in the brain are not spared from the deposits of cholesterol and other forms of fats. If you are prone to having these deposits, all your blood vessels will have the same tendency to have them. Hence, when the opening of your blood vessel in the brain is narrowed by these deposits which have been accumulating for years, these blood vessels are prone to be blocked by blood clots which have been traveling in your bloodstream. Since the opening of the blood vessel is narrowed, it could easily be plugged by a clot which had been admixed with your blood.  With the blockage, blood could not pass through, and a certain area of your brain is suddenly deprived of blood, resulting in stroke, which is now considered as due to a cerebral thrombosis. Had it not been for the narrowed blood vessel, stroke could not have happened.

Diagrammatic representation of a blood vessel in the brain which has been deposited with cholesterol and fats (A) and then a blood clot that plugs its opening (B). Figure 1. Diagrammatic representation of a blood vessel in the brain which has been deposited with cholesterol and fats (A) and then a blood clot that plugs its opening (B).

Due to cerebral embolism

While your brain is left undisturbed for so many years, in other parts of your body, blood clots may have been formed. Some of these are attached to the inner structures of your heart.When your heart is behaving properly, they remain where they are, without producing any trouble at all. However, when it suddenly misbehaves, its rhythm is greatly disturbed that it is now out of sync. Consequently, its pumping becomes erratic and produces vibration that it is now medically described as fibrillating. When this takes place, blood clots from its inner chambers are thrown out in the blood which goes into circulation. When these blood clots reach the brain, they could block a blood vessel, resulting in stroke which is due to a cerebral embolism.

Figure2.Diagrammatic representation of a blood vessel in the brain which was never deposited with cholesterol and fats (A) but then a blood clot arrives plugging its opening (B). The diameter of the opening decreases as its location moves away from the heart—hence, very much prone to plugging.

Figure2.Diagrammatic representation of a blood vessel in the brain which was never deposited with cholesterol and fats (A) but then a blood clot arrives plugging its opening (B). The diameter of the opening decreases as its location moves away from the heart—hence, very much prone to plugging. 

Due to ruptured blood vessel

The wall of the blood vessels in your brain is very thin. This structural design is meant to allow easier transfer of oxygen from the blood to yourbrain and the transfer of carbon dioxide from yourbrain to the blood. In short, it is meant to allow easier exchange of gases. With this design, however, it cannot withstand high blood pressure. Thus, it is necessary that you always maintain your blood pressure at normal level because if you do not, a blood vessel in your brain could rupture, and you will suffer from stroke.

Figure 3. Diagrammatic representation of a normal blood vessel in the brain (A) and the ruptured blood vessel in (B) where the blood goes out  through the leakage.

Figure 3. Diagrammatic representation of a normal blood vessel in the brain (A) and the ruptured blood vessel in (B) where the blood goes out  through the leakage.

(To be continued)

Definition of, and lifestyle intervention measures for, prediabetes

Definition

Prediabetes is defined as a medical condition wherein your fasting blood sugar is over the normal values, but you are not yetclassified asdiabetic[1]. It is therefore a stage wherein you are about to enter the population of diabetic patients. While it is true that you are not yet adiabetic, this is the right time to implement some intervention measures so that your medical condition will not get worse and will not be transformed into Type 2 diabetes mellitus, when the management is more complicated and more expensive.

To find out if you are a prediabetic or not, you can request your medical doctor to prepare for you a laboratory order for blood chemistry examination, wherein fasting blood sugar (FBS) is one of the tests. If the result of your FBS is between 70-105 mg/dl, then you have normal values. If the value is equal to or greater than 126 mg/dl, then you might have diabetes mellitus. If the value lies between 105 and 125 mg/dl, then you are a prediabetic.If you are a prediabetic, you can do a number of things so that your condition will not get worse—if not lowering your fasting blood sugar to normal level.

Lifestyle intervention measures

Engage in regular physical exercisesand burn your excess abdominal fat[1]

If your waist circumference is 35 inches or longer if you are a woman or 40 inches or longer if you are a man, it is highly probable that you have abdominal fat which needs to be shed off. (Consult Powertec 112, 113, 114, 115). You need to do some abdominal exercises and regular walking. If you would like to do some other forms of physical exercises that you enjoy, then do them! For as long as you can afford to do a particular physical exercise, you are not restricted to do it because as a prediabetic you really need to have regular and periodic physical exercises. By doing this, you will burn your excess abdominal fatand you will increase the competence of your insulin—a substance needed by your cells to pick up your sugar in the blood.

 

 

Reduce your weight if you are overweight[1]

If you are overweight, then you need to do some dietary and physical exercises programs that will lower your weight. Consult Powertec 20, 21, 22on how to implement these programs. Being overweight predisposes you to acquire Type 2 diabetes mellitus.

Reduce your fat intake[2]

If you are a prediabetic, you need to have dietary modification which includes reduction in yourfat intake. As much as possible, yourfat intake is composed mainly of the unsaturated fatty acids which include both the monounsaturated and polyunsaturatedones. (Consult Powertec 63). You can take some amount of saturated fatty acids, though, because you also need them to maintain your health.

Increase fiber in your diet[2]

If you are overweightand prediabetic, it is recommended thatyou increase the amount of fibers in your diet. Foods rich in fibers are apples, peaches, plums, prunes, bananas, oats, barley, dried peas, beans, lentils, vegetables, brown rice, nuts, and seeds. (Consult Powertec153). If the amount of fibers in your diet is relatively significant, unknowingly, you will reduce the number of calories that you will take in every meal, thereby helping in your weight reduction.

Avoid simple carbohydrates

You need to avoid simple carbohydrates, such as candies, chocolates, cakes, honey, soft drinks, ice cream, and table sugar. Avoid putting sugar in your coffee. If you are very fond of fruits, avoid the sweet ones, such as grapes, mangoes, and pineapple. If you take a lot of simple carbohydrates, your blood sugar will immediately rise up.

 

References:

  1. http://www.mayoclinic.org/diseases-conditions/prediabetes/basics/definition/con-

20024420

  1. Pratley RE, Matfin G. Pre-diabetes: clinical relevance and therapeutic approach. British Journal of Diabetes and Vascular Diseases. 2007;7(3):120-129.

http://www.medscape.com/viewarticle/562039_8

Nutritional guidelines to prevent heart diseases(Part 2)

Limit your intake of salt

As mentioned and discussed in Powertec 152, increased intake of salt during yourelderly life may increase your blood pressure (hypertension) because your kidneys could not eliminate as much salt as they used to be from your body. When you start to experienceit and it remains unchecked and untreated for several number of years, your heart enlarges, and you have what is called in medicine as cardiomegaly. When you have this medical condition and still you refuse to take the necessary medications or fail to take them, your heart will eventually fail, and you have the condition medically known as heart failure. You may die from it.

It is clear from the preceding section that too much intake of salt from your diet could lead to a heart disease; therefore, immediately after knowing that you cannot afford to take excess salt, you need to exert extra caution and effort in determining which food(s) to take and not to take.

Increase your intake of foods rich in fiber

Beneficial effects

Dietary fibers are substances present in foods which are not digested in your gastrointestinal tract (GIT). This means that they stay in, and pass through, your GIT without being digested and transformed into another substance. They remain as they are, without contributing any substance, vitamins, or minerals to your body. However, they have the following important functions:(1) they increase the bulk of your stool, leading to promotion of your bowel movement, and thus preventing constipation and colon cancer, (2) prevent the absorption of cholesterol, which is incriminated as one of the causes of diseases in your heart and blood vessels[1], and (3) lower the total food calories that you will take each daycausing you to lose weight and have lower blood glucose.

Since the fibers remain undigested in your GIT, they form greater portion of your stool; since your GIT is sensitive to the volume of your stool, the bulkier your stool is, the more your GIT will contract, and your stool will be finally squeezed out into the outside. Hence, if you have on and off constipation, taking adequate amount of fibers daily will help you overcome it. When you have regular bowel movement, the time contact between your stool and the inner lining of your intestine is shortened. With this, the chance that your food—which could be an unhealthy food—willinduce the start of cancer in your intestine will be lessened. Hence, you will be protected from it. In addition to your protection from constipation and cancer, fibers will help you avoid being overweight and having high blood glucose. These take place because more fibers in the diet will make you feel full from the food that you have been eating sooner than when there are no adequate fibers.As a result, you will eat less than when your diet is fiber-free.

Types of fibers

Although dietary fibers could not be digested, some of them could be dissolved in water, while others remain undissolved. Hence, there are two types of fibers: (1) water-soluble, and (2) water-insoluble. Examples of each type are listed in Table 1 below:

Food sources of dietary fibers                             (End of a series of 2)

Reference:

  1. Roth, Ruth A. Nutrition and Diet Therapy. Singapore: Delmar Learning, 2007.

Nutritional guidelines to prevent heart diseases(Part 1)

Eat foods low in saturated fat and cholesterol

The quantity and quality of foods that you take play a great role in the development of medical problems, such as heart diseases, andit has been established in several researches that foods rich in fatsand cholesterol are notorious and paramount in doing so. However, only the saturated fatshave been found to contribute in the development of heart diseases—and not all forms of fats. The so-called unsaturated, consisting mainly of themonounsaturated and polyunsaturated fats, are not incriminated as possible causes of the said diseases; therefore, they can be taken in moderate amounts.

Cholesterol is a fatty substance (lipid) which is either produced in the body or taken from foods. Biochemically, they can be formed in your body from saturated fats that you have previously taken in. This is the reason why you are often advised to limit your intake of red meat, such as beef, pork, and lamb, because they contain a lot of saturated fats. Another way of having increased cholesterol in your body is taking a lot of foods rich in it, such as quail and chicken eggs, animal-derived cooking oil, cookies and butter, and many more.

To help you avoid taking foods rich in saturated fat and cholesterol, every time you buy a packed food from a supermarket or a store, always look at the “Nutrition Facts”, and find out the saturated fat and cholesterol contents of the food stuff. Select the foods that contain the least amount of saturated fat and cholesterol. Therefore, it is not advisable that you go shopping for foods with very limited time to do it! Allot adequate time for your shopping, especially if your intention is to buy foods for yourself and your family members.

Limit your intake of salt

As you grow older, the capacity of your kidneys to eliminate excess salt that you took in from your diet is decreased. For this reason, you will reach a certain age wherein you retain unwanted salt because your kidneys could not eliminate them. When the concentration of salt in your blood is higher than what is normally needed, water which is normally inside your different cells will now enter your blood vessels, and this movement of water will increase your so-called intravascular volume—the blood volume inside your blood vessels—leading to increase in your blood pressure. Thus, when you realize that you cannot afford to take in more salt than what you used to do, limit your salt intake.

There are many ways of avoiding taking in more salt that what you need. Firstly, avoid eating out as much as possible. The reason for this is that you cannot control the amount of salt that is mixed in your meals in the restaurants and other establishments which cater to serving foods to customers, in contrast to what is cooked at home wherein you could instruct your cook to limit the amount of salt admixed in it. Secondly, if you are eating out and find out that the food(s) you ordered is(are) very salty, discontinue taking it (them)! It seems that you would be wasting money when you do it! However, it is good for your health, and it will prevent you from having your blood pressure increased! Thirdly, whenever you buy packed food, always look at the “Nutrition Facts”, and look at the salt or “sodium” content. Select food(s) with the least amount of salt—less than 7% as much as possible. Expect, however, that when you are buying processed food(s), that the salt content is relatively high; thus, as much as possible, resort to buying fresh foods and cook them at home—if needed.

(To be continued)

What is endothelium?(Part 4)

Ways of preventing injury to the endothelium

Avoiding or stopping smoking

One of the products of smoking is nicotine, and this substance injures the endothelium which ultimately leads to atherogenesis. Specifically, smoking promotes the oxidation of the low-density lipoprotein (LDL) which—aside from decreasing the concentration of nitric oxide {Consult Powertec (149)}—promotes the migration of the white blood cells (monocytes) in the midst of endothelium, thereby injuring it[1]. Hence, avoid, or stop, smoking as soon as possible.

Simplified steps in protecting your endothelium

  • Consult a medical doctor and have your blood pressure checked;
  • If your blood pressure is elevated, your medical doctor will prescribe youwith medication(s). If so, take them regularly. After two weeks or one month, go back to your medical doctor, and have your blood pressure checked again. If your blood pressure is still high, he will add another medication. If already controlled, he will advise you to continue your medication(s);
  • If you have elevated blood pressure, aside from giving you the necessary medication(s), your medical doctor will request you to have blood chemistry examination, complete blood count, and urinalysis.The blood chemistry examination will consist of the fasting blood sugar, blood urea nitrogen, creatinine, uric acid, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and the lipid profile. The lipid profile, in turn, will consist of the total blood cholesterol and triglyceride, high-density lipoprotein, low-density lipoprotein, and the vey low-density lipoprotein;
  • The lipid profile test is very important because it will tell you if you need additional medication(s). If your total cholesterol, and/or your total triglyceride, and/or your LDL cholesterol is (are) high, you need to take drug belonging to the statins. If the predominant elevation falls on the triglycerides, you need to take drug under fenofibrates;
  • If your fasting blood sugar is elevated, it is possible that you are suffering fromdiabetes mellitus. Initially, your medical doctor may design for you dietary therapy and try it for some months. If it does not work after giving a try, you will be prescribed with anti-diabetic drug(s).
  • If your blood pressure is elevated and/or you have abnormalities with your blood lipids and/or your blood sugar is elevated, you need to be very careful with your diet. Avoid high salt and high fat diet. Avoid taking simple carbohydrates like candies, chocolates, sugar, ice cream, and soft drinks. Limit your intake of rice to one cup per meal, and take a lot of foods rich in fibers, such as corn, vegetables, fruits, and cereals;
  • Have a regular and periodic physical exercises. If you are over 50 years old, a 30-minute walking, three times per week, will do you a lot of good! If you are below 50 years old, you can do more than what is prescribed for the elderly. In addition to walking, you can run and you can do bicycling;
  • Stop, or avoid, smoking.

Implement preventive measures with dispatch

The secret of successful preventive measures is to implement them as early as possible. The moment you realized that you have hypertension, and/or hyperlipidemia, and/or diabetes mellitus, you need to start implementing all the measures that have been enumerated in the preceding. The reason for this is that as you withhold doing the preventive actions, complications of the disease have been setting in. Physically, you will not feel it (them)! However, in the recesses of your different organs, such as your heart, kidneys, and blood vessels—be it small, medium, or large—structural destructions have been going on! By the time you want to do something, it is too late! Hence, act without delay!

(End of a series of 4)

Reference:

  1. Powell JT. Vascular damage from smoking: disease mechanisms at the arterial wall. Vasc Med. 1998;3(1):21-8.http://www.ncbi.nlm.nih.gov/pubmed/9666528.

What is endothelium?(Part 3)

Ways of preventing injury to the endothelium

Correcting yourhigh level of LDL-cholesterol

It has been reported that if the level of your LDL-cholesterol is very much above the normal ranges, the production of nitric oxide (NO) by your endotheliumwill be reduced[1]. When this takes place, the following complications will follow {other complications were discussed in Powertec (148)}:

Leukocyte adhesion[1]

As mentioned inPowertec (148), there are three types of cells in the blood. One type of these cells is called the white blood cells (WBCs). The WBCs are also called the leukocytes.When the production of NO is depressed, the adhesion of leukocytes to each other and to other substances is very much increased, conducive to the formation of clots and plugs that will obstruct the passageway of blood. In fact, this change in the property of the leukocytes will further accelerate the formation of the so-called plaques which attach themselves in the endothelium, leading to the narrowing of the tubular blood vessels.

Oxidative stress[1]

When the LDL-cholesterol is oxidized, the formation of the substance called caveolin-1 leads to decrease in the concentration of NO. This biochemical mechanism has been considered as the initial and primary cause of atherosclerosis. Since NO is known to prevent the oxidation of LDL-cholesterol, its availability in your blood should always be high. If its level is low and the level of yourLDL-cholesterol is high, the probability that the lipoprotein will be oxidized is high. Thus, the level of yourLDL-cholesterol should always be checked and controlled.

Drug of choice to correct your elevated LDL-cholesterol

To correct your high level of LDL-cholesterol, your medical doctor will prescribe you with a class of drug known as statins. Generic names belonging to this class of drug are rosuvastatin, atorvastatin, and fluvastatin—to mention some. Your medical doctor needs to prescribe you with this class of drug because statins have been found to not only lower your LDL-cholesterol but it has other beneficial effects for the improvement of your endothelial function[1].

 

Correcting your blood sugar

The other disease which could be injurious to your endothelium is diabetes mellitus (DM)[3]. If you have DM, your blood sugar is very much increased—also called hyperglycemia in medical parlance. As much as possible, when you have detected for the first time—with the help of your medical doctor—that your blood sugar is increased, that you have immediately taken action to correct it. If your medical doctor prescribed you with a certain drug, or set of drugs, you should have taken them regularly and religiously.If your blood sugar is left unchecked for a considerable number of years, it will enhance the attachment of plaques in your endothelium, leading to the development of atherosclerosis, hypertension, and other cardiovascular complications of diabetes. However, up to the present time, a detailed explanation, in terms of biochemical and cellular connections, between high blood glucose levels and complications in the cardiovascular structures remains incompletely understood [2].

While there has been no clear and detailed explanation on the link between hyperglycemia and endothelial dysfunction, it is known that in diabetic state there is an increased tendency for oxidative stress and oxidation of lipoproteins, especially the LDL-cholesterol[2]. As mentioned in the preceding, these two factors have been established as possible causes ofNO depletion. Hence, hyperglycemia has a big role in the destruction of endothelium, and there is a need to control it.

The simplest way to find out if your diabetes has more or less adversely affected the competence of your endothelium is to request for urinalysis. If protein, specifically albumin, is detected in your urine, it is possible that endothelial dysfunction has started[2], and you really need to control your blood sugar.

(To be continued)

References:

  1. Davigon J, Ganz, Peter. Atherosclerosis: evolving vascular biology and clinical implications, role of endothelial dysfunction in atherosclerosis. Circulation. 2004;109: III-27-III-32. doi: 10.1161/01.CIR. 0000131515.03336.f8.
  2. Hadi H, and Suwaidi J. Endothelial dysfunction in diabetes mellitus. Dovepress, Vascular Health and Risk Management. 2007;Dec; 3 (6):853-876.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2350146/

  1. Preston RA, WencheJy, Jimenez, JJ, Mauro, LM, Horstman, LL, Valle, M, Aime, G, and Ahn, YS. Effects of severe hypertension on endothelial and platelet microparticles. Hypertension. 2003;41:211-217. doi: 10.1161/01.HYP.0000049760.15764.2D.

What is endothelium?(Part 2)

Ways of preventing injury to the endothelium

Controlling your high blood pressure

In the study of Preston, RA et al, titled “Effects of severe hypertension on endothelial and platelet microparticles”, two markers were used to find out if indeed hypertension injures the endothelium. One of these markers is called endothelial microparticles (EMP), and it   is released in the bloodstream when the lining of the endothelium is damaged or destroyed. In this study, investigators found out that EMP was very much elevated in the subjects with high blood pressure[1]. This shows that existing high blood pressure could continually and inevitably injure your endothelium, and there is an urgent need to control it.

There is therefore a need to see your medical doctor soonest to control your high blood pressure. If synthetic drugs will be prescribed to you, the drug of choice should be any one belonging to the class of angiotensin-converting enzyme (ACE) inhibitors, because this has been shown to contribute in the restoration of good endothelial function [2]. Examples of generic names belonging to this classare captopril, perindopril, imidapril, and many more. The generic names underthis class of drugs end in “pril”. Thus, if you have elevated level of LDL-cholesterol, in addition to having high blood pressure, ensure that yourmedical doctor prescribes you with any pill belonging to this class of anti-hypertensive drug.

Correcting yourhigh level of LDL-cholesterol

It has been reported that if the level of your LDL-cholesterol is very much above the normal ranges, that the production of nitric oxide (NO) by your endotheliumwill be reduced[2]. When this takes place, the following complications will follow:

Arteries constrict[2]

Since NO is responsible for the dilation of your blood vessels, the arteries in particular, its low level will lead to the elevation of your blood pressure, since the constriction of your arteries will predominate.

Platelets clump and attach themselves in the endothelial injury[2]

In your blood, there are three types of cells: (1) white blood cells, (2) red blood cells, and (3) platelets. The platelets play a significant role in the formation of blood clots which serve as plugs to any cut in your arm, legs, or in any external part of your body. Without platelets, it is difficult to stop any form of bleeding. When the level of NO in your blood is very much reduced, theplateletseasily form a clump and attach themselves at the injured site in your endothelium forming the so-called plaques which eventually block your arteries and make them inelastic.

This change in the properties of platelets was also shown in the study of Preston, RA et al as stated in the preceding wherein platelet microparticles (PMP) were elevated in subjects whose blood pressure was very high[1], indicating that platelets have changed in their biological behavior. It is possible that low NO initiates this change in the platelets, and severe hypertension aggravates it.

Smooth muscle cells grow in number and migrate[2]

Your smooth muscle cells which compose the walls of your blood vessels are well-behaved when the level of NO in your blood is normal. However, when its level decreases as a result of having elevated LDL-cholesterol in your blood, your smooth muscle cells become active and aggressive, such that they go out of their way and go to other places which normally are not their territories. They cannot be controlled, and they go astray! Consequently, even in the lining of your endothelium which is in intimate contact with your flowing blood, they grow and invade. These seemingly foreign invaders make your endothelium thicker and more inelastic leading to the development of atherosclerosis and hypertension.

(To be continued)

References:

  1. Preston RA, WencheJy, Jimenez, JJ, Mauro, LM, Horstman, LL, Valle, M, Aime, G, and Ahn, YS. Effects of severe hypertension on endothelial and platelet microparticles. Hypertension. 2003;41:211-217. doi: 10.1161/01.HYP.0000049760.15764.2D.
  2. Davigon J, Ganz, Peter. Atherosclerosis: evolving vascular biology and clinical implications, role of endothelial dysfunction in atherosclerosis. Circulation. 2004;109: III-27-III-32. doi:10.1161/01.CIR. 0000131515.03336.f8.

What is endothelium?(Part 1)

Nature of endothelium

Endothelium is also called tunica intima, and it is the innermost layer of your artery and your other blood vessels {Refer to Powertec (146)}. As part of your artery,  you will surely arrive at a conclusion that its main function is to support your arterial wall. To some extent, it does, but it has other functions much more important than being support of your artery. This will be the center of discussion in this article.

Functions of endothelium

Aside from serving as the innermost lining of your artery, the endothelium has the following more important functions:

  1. Maintenance of the vascular tone. It produces the substance nitric oxide which is responsible for the dilation of your artery. It also produces endothelin and angiotensin II which are responsible for the constriction of your artery[1]. For all of these reasons, the endotheliumcontrols the diameter of your artery, increasing or decreasing it as needed. If there is a need to increase your blood pressure to a certain degree, then your endothelium increases it by effecting constriction of your arteries; if there is a need to lower it, then your endothelium will dilate your arteries. Your endothelium does this spontaneously without your knowing it and without waiting for you.
  2. Inhibition and stimulation of smooth muscle cell proliferation and migration[1]. The smooth muscle cells should be located at the right places. If their multiplication and migration are not controlled, then they will wreak havoc to your cardiovascular For this reason, the endothelium balances these two processes. If, however, your endothelium is being injured by an abnormality in your body, it may react spontaneously to allow the proliferation and migration of smooth muscle cells to protect itself.
  3. Inhibition and stimulation of thrombogenesis and fibrinolysis[1].Thrombogenesis refers to the formation of obstructions in your blood vessels, particularly in the arteries. Fibrinolysis, on the other hand, refers to the dissolution and dis-aggregation of possible obstructions.

From the foregoing discussion, it can be gleaned that if the endothelium is damaged, the balances that it does so that no opposing force will predominate will be damaged as well, and you will have a lot of problems.

Factors injurious to the endothelium

High blood pressure

Being the innermost lining of the artery, the endothelium takes the brunt of the flowing blood. If the blood pressure is very much elevated compared to the normal ranges, it will injure the endothelium, and this injury is the beginning of a process which will develop into atherosclerosis, then leading to hypertension {Refer to Powertec 146}.

High level of LDL-cholesterol

When the level of your LDL-cholesterol is very much above the normal ranges, it suppresses the endothelium to produce nitric oxide[1]—a substance whose one function is to dilate the blood vessels. In the absence of sufficient nitric oxide, your blood vessels, specifically the arteries, constrict leading to hypertension, which will, in turn, lead to the development of, or aggravate existing, atherosclerosis.

Ways of preventing injury to the endothelium

Control the high blood pressure

You should know your current blood pressure. You are very much negligent of your health if at this time you still do not know your current blood pressure! If your blood pressure is above the normal ranges, you need to consult a medical doctor so that you will be prescribed with the necessary medications. In addition, you will be requested to have blood and urine examinations whose results will provide your medical doctor with an idea on the severity of your medical condition. It is not enough that your blood pressure is controlled; in addition, other aggravating factors, such as abnormalities in your blood chemistry, need to be corrected, so that your hypertension will not get worse.

(To be continued)

Reference:

  1. Davigon J, Ganz, Peter. Atherosclerosis: evolving vascular biology and clinical implications, role of endothelial dysfunction in atherosclerosis. Circulation. 2004;109: III-27-III-32. doi:10.1161/01.CIR. 0000131515.03336.f8.

Role of cholesterol in the development of cardiovascular diseases(Part 2)

Anatomy of the blood vessel wall

You have three types of blood vessels: (1) arteries, (2) veins, and (3) capillaries. Your arteries carry the blood from your heart and deliver them to different parts of your body. You veins collect the blood from the different parts of your body and return it to the heart. Your capillaries, on the other hand, connect your network of arteries to your network of veins.In the development of hypertension and heart diseases, the type of blood vessels that are primarily involved are the arteries.Therefore, the center of discussion in the next few sections will be on them.

Your arteries can be likened to your water pipes at home. They are tubes wherein fluid passes through. In your water pipes, water passes through them; in your blood vessels, blood will pass through them. Your arteries are relatively thick tubes, and they are made this way because they need to withstand the high pressure generated by your blood and the regularpumping of your heart.

Tunica adventitia

The wall of your arteries are made up of three layers: (1) tunica adventitia, (2) tunica media, and (3) tunica intima, also known as the endothelium.The tunica adventitia is the outermost layer, the tunica media is the middle layer, and the tunica intima is the innermost layer. The tunica adventitia is responsible for attaching your arteries to the surrounding tissues, thereby preventing them from moving astray. In addition, it provides some strength for your arteries. The tunica media is mainly responsible for providing the strength of your arteries to contain your varying blood pressure. Meanwhile, the tunica intima provides the internal lining of your arteries.

Important role of the tunica intimaor endothelium

Since the tunica intima or endothelium is the innermost lining of your arteries, it is in intimate contact with the flow of your blood. As your blood flows in your arteries, your endothelium offers a frictional resistance to such flow; therefore, the endothelium receives the brunt of the flowing blood. In the parlance of medicine, this is called the shearing effect of the flowing blood. When your blood pressure is very much increased compared to the normal values, this shearing effect also increases, and your endothelium will be injured. The higher the blood pressure is, the higher and more serious the injury to your endothelium will be. This injury will be the beginning of developing the so-called atherosclerosis wherein fatty substances are attached to the lining of the endothelium, giving rise to inelastic arteries which will, in turn, lead to the development of hypertension and heart diseases.

Injury to the endothelium and high level of LDL-cholesterol

In the development of atherosclerosis (deposition of fatty substances in the endothelium), it has been established that the first stage in the process is the infliction of injury to the endothelium.This injury to the endotheliumare caused by increased blood pressure and the increased level of LDL-cholesterol[1]. Hence, if you have elevated blood pressure and you have elevation of the LDL-cholesterol, your hypertension will get worse as days go by, if you do not take medicines to control your high blood pressure and the elevated level of LDL-cholesterol.

The LDL-cholesterol has dual effects in the causation and worsening of atherosclerosis. Firstly, it decreases the production of nitric oxide which is responsible for the dilation of the arteries[1]. Thus, in the absence of nitric oxide, you are prone to have elevated blood pressure because of constriction of your arteries.Secondly, with increased level of LDL-cholesterol in the blood, these fatty substances, together with platelets, could attach themselves in the injured sites in the endothelium. This will make the arteries inelastic and obstructed—be it partial or total—leading to the development of hypertension and heart diseases.

Reference:

Davigon J, Ganz, Peter. Atherosclerosis: evolving vascular biology and clinical implications, role of endothelial dysfunction in atherosclerosis. Circulation. 2004;109: III-27-III-32. doi:10.1161/01.CIR. 0000131515.03336.f8.