The Xist Gene

The Xist Gene

In our today's efficiency-oriented society one of the greatest fears of parents is the diagnosis of their offspring with a genetic disorder. It is driven by the concern of ones child not being able to fit into our society due to mental or physical developmental disabilities which are often caused by the presence of an additional chromosome in the child's genome.
Lately scientists have achieved a milestone in the research about such trisomy disorders. The idea of being able to eliminate the affects of the genetic disorder all orbits around the discovery of the so called Xist gene.
Researchers have found this gene in the investigation of the natural process of silencing one of the two x chromosomes in female mammals. The presence of this x inactivation gene in the x chromosome helps to prevent the gene expression the particular chromosome. When activated, the Xist gene covers the the chromosome like a blanket.
Now researchers are trying to adapt this method to other chromosomes and hope, one day to be able to silece additional chromosomes in humans and thereby prevent the gene expression causing developmental issues in humans affected by trisomy dissorders.

http://www.nature.com/news/researchers-turn-off-down-s-syndrome-genes-1.13406

Xist (Gene)

Chromosome disorders are diseases which occur to people due to an abnormality within the individuals chromosomes. One example of an chromosome disorder would be down syndrome, this chromosome disorder is caused when a person is born with an extra copy of the chromosome 21. Similarly to this there is a gene known as the Xist which is likely to effect a persons X chromosome changing the developmental process within females. There are teams around the world that are researching into the Xist gene seeing if they could use it in order to treat, or cure chromosome disorders such as down syndrome. The Xist gene is an RNA gene that acts in the early process of mammalian females/placental mammals development and causes a major effect on the X inactivation process.  During the development of the being the Xist gene transcriptionally silences one of the two pairs of X chromosomes, thus providing and equivalence between that particular female and other males, due to the shortage of an X chromosome. It's full name is X-inactive specific transcription. When a person has a disease such as down syndrome it means that they have copy of already existing chromosome so in order to treat it or "cure it" scientist are using the Xist gene to get ride/silence one of the two existing pairs of 21 chromosomes. Using genome editing with zinc finger nucleus's, scientist insert a large portion of the Xist gene into the locus of the chromosome 21, in down's syndrome stem cells. The Xist coats chromosomes 21 and triggers stable 'hetero-chromatin modification, supposedly silencing DNA to form a chromosome 21 barr body.' Treating the down syndrome patient.

Xist Gene

The Xist gene is used by the body to silence one X chromosome, in a pair of homologous X chromosomes. Xist is a RNA gene, which comes from the splicing of non-coding RNA (which don’t code for proteins).The Xist gene will silence an X chromosome in female mammals so that the dosage between males and females are equal. The process of gene inactivation begins at the X inactivation center, where the Xist gene is located.

Down syndrome is caused by an extra 21 chromosome in the body, also known as trisomy 21. Due to the accumulated information about the Xist gene, and its effects, scientists believe they could silence the extra chromosome with the Xist gene. An experiment performed by Jeanne Lawrence showed that the Xist gene could be used to silence the extra 21 chromosome (Chr21).

Xist Gene

Xist gene (X-inactive specific transcript) is an RNA gene, and is affiliated with the non-coding RNA class. Diseases associated with Xist gene are x-inactivation, familial skewed or craniofrontnasal dysplasia. The Xist RNA is expressed on the inactive chromosome rather than the active one. It is formed in a way resembling the mRNAs. X chromosomes without the Xist gene will not be inactivated, however duplication of it on another chromosome results in inactivation of that chromosome. 

Function:

X inactivation is developed early in mammalian females that transcriptionally silence one of the X chromosomes, which results in dosage equivalence in males and females. The process depends on multiple factors, such as the region of chromosome X which is also called the X inactivation centre (XIC). The XIC compromises sever non coding and protein-coding genes .Xis gene was the first gene to be identified with the X inactivation Centre. This gene is expressed solely from the XIC of the inactive X chromosome, and is needed for the spread of the X-inactivation. 

Xist gene and it's relation to chromosome disorders

Do you have a problem with your chromosomes and you don't know how to fix it? Do you need some things sliced and diced? Well we have the solution for you, introducing the new and improved Xist gene who can solve all of your problems!!!

What is it and how can it help

Xist stands for X inactive specific transcript, this gene is found in the early developmental process of mammalian females. The genes job is to slice one of the pairs of X chromosomes. Scientists believe that they can use this gene to fix the chromosome disorders, for example down syndrome. When the Xist gene is activated a RNA molecule is produced and it coats the surface of the chromosome and it blocks other genes form being expressed. 

The Xist gene slicing for down syndrome.

Scientists have found a way to slice chromosome 21 when down syndrome is present.

Xist (gene) - Yoonsik Park

XIST (X-Inactive Specific Transcript)

Yoonsik Park

What is it?

X inactivation occurs in the early developmental stage of female mammals where one of the two X chromosomes are silenced during transcription. The Xist gene is the RNA responsible for this, according to http://www.ncbi.nlm.nih.gov/gene/7503. This process can be seen in the picture below.

http://mmg-233-2014-genetics-genomics.wikia.com/wiki/File:Expression-of-Xist.jpg

What is significant about this is the possibility to use it to shut down extra chromosomes that cause chromosomal disorders such as Trisomy-21 and Trisomy-18.

https://mydoctor.kaiserpermanente.org/ncal/Images/trisomy18_tcm63-951309.png

For example, Trisomy-21, or better known as Down Syndrome, is caused from an extra chromosome 21, causing other abnormal gene expressions. People with Down Syndrome will have abnormal physical characteristics such as short neck and short height and there is a high chance that they will have problems with learning.

http://www.nature.com/news/researchers-turn-off-down-s-syndrome-genes-1.13406
http://phenomena.nationalgeographic.com/2013/07/17/how-to-shut-down-the-extra-chromosome-in-downs-syndrome/

XIST

While treatment for genetic disorders seems improbable, as the therapy would have to affect each cell in the patient's body, there has been promising development in this field, as scientists have found a gene that could potentially remove, that is silence, extra chromosomes that arise in genetic disorders such as Down's Syndrome. 

This gene is called XIST, short for X-inactive specific transcript, and it is found on the X chromosomes of all female placental mammals. Because females have two X chromosomes, while males have only one, the greater amount of material produced by the two X chromosomes could be dangerous, so one of the X chromosomes is silenced, that is the chromosome is coated in heterochromatin, a substance which is created by the XIST gene, and does not allow most of the chromosome to undergo gene expression. 

Scientist are looking into using the gene to silence other chromosomes. The gene could potentially be used to treat patients with disorders with extra chromosomes. Researchers have successfully silenced an extra chromosome 21 in an artificially grown Down's syndrome cell.

There is much work to be done before this treatment can actually be used to help people, and there is much debate on whether it would work, because there is a chance that the gene would silence other chromosomes instead of the one that was targeted.

http://phenomena.nationalgeographic.com/2013/07/17/how-to-shut-down-the-extra-chromosome-in-downs-syndrome/

Xist gene

Xist gene and how it relates to chromosomal disorders?

Xist gene- X inactive specific transcript 

Xist is an RNA gene on the X chromosome of the placental mammals that acts as a major effector of the X inactivation process. It is a component of the Xic - X-chromosome inactivation centre - along with two other RNA genes (Jpx and Ftx) and two protein genes (Tsx andCnbp2). The Xist RNA, a large transcript, is on the inactive chromosome and not on the active one. However, it remains untranslated. It has been suggested that this RNA gene evolved at from a protein coding gene that became a pseudogene.

Some new studies have shown that it may help into chromosomal disorder treatment. 

XIST Gene

New studies all over the world have brought to light a newly discovered gene called the Xist gene. This gene is thought to be able to aid in the treatment of chromosomal disorder like trisomy 21; down syndrome. It would aid in the treatment as so far research has showed that the xist gene is able to silence a chromosome. With the help of this newfound ''cure'' researchers would be able to identify reasons behind chromosomal disorder and then develop treatments and ways of prevention.

What is the XIST gene?
The xist gene is an RNA gene found on one of the two X chromosomes in all mammalian females. During a female's development one of the two X chromosomes inside her is silenced by something called a heterochromatin formation; which is a tightly packed form of DNA. This is done in order to make sure that a process called X inactivation occurs. X inactivation is the process in which the heterochromatin formation ensures that equal levels of the X-linked gene are expressed in both,  XX females and XY males.

The Xist Gene and Down Syndrome

New studies have shown that the Xist gene could be used to treat chromosome disorders such as Down Syndrome by silencing a chromosome. The method could help researchers to identify the cellular pathways behind the disorder's symptoms, and to design targeted treatments.

What is the Xist gene?

Figure 1- The expression of the Xist gene on one of the X
chromosomes leads to the recruitment of protein to that
chromosome that are required to inactivate the chromosome. 

Xist, which stands for X-inactive specific transcript, is an RNA gene on the X chromosome in placental mammals which affects the X inactivation process. According to NCBI Gene, X inactivation is an early developmental process in mammalian females that transcriptionally silences one of the pair of X chromosomes. As seen in Figure 1, this is because when the Xist gene is activated, it produces an RNA molecule that coats the surface of a chromosome like a blanket, which blocks other genes from being expressed (Beth Mole, nature.com).

Xist gene and Down Syndrome

Figure 2- The Xist gene can be used to
treat Down Syndrome as it
silences the extra copy of
chromosome 21

According to a study conducted by Jiang et al, the Xist gene can be used to silence one of the two X chromosomes carried by all females mammals, which is beneficial for chromosome disorders such as Down Syndrome as it can silence the extra copy of chromosome 21.











Bibliography:

Mole, Beth. Nature.com. Nature Publishing Group, n.d. Web. 12 May 2016.

http://www.nature.com/news/researchers-turn-off-down-s-syndrome-genes-1.13406

"XIST." Genetics Home Reference. N.p., n.d. Web. 12 May 2016.

https://ghr.nlm.nih.gov/gene/XIST#location

Coronary Heart Disease

Factors leading to coronary heart disease (CHD)

What is CHD?
It is a condition that children are born with, which can affect the shape and function of the heart. It is one of the most common birth defects in the world, as 1 out of every 100 babies are born with it. Although not deadly in all cases, more than half the children born with it, are exposed to a significant risk of dying if not partaking in surgery to correct the defect. Today we are aware of 35 different types of CHD. Although it has been around for many years, little is certain about the disfunction and a cure is yet to be found. To expand on the disease itself, we must be aware that our coronary arteries narrow, causing the supply of oxygen through blood to cut short. At first the decrease in blood flow will not lead to the development of coronary artery disease however as time goes by the risk of exposure grows.

Symptoms?
Angina (chest pain): the pressure or tightness felt in chest is due to CHD. The pain is referred to as an angina and occurs in the middle of left side of the chest, close to your heart. It most often occurs when exposed to physical or psychological stress.
Shortness of breath: due to the fact that the heart cannot pump the blood and it's usual, normal speed, your supply of oxygen will decrease causing you to develop shortness of breath as well as extreme fatigue
Heart Attack: if you are not exposed to surgery as soon as possible whilst diagnosed, it may lead to your arteries becoming completely blocked which then leads to heart attack.
Some other, minor symptoms that occur would be related to poor feeding, decrease in weight as well as short and fast breaths.

Causes/Risk factors?
Coronary artery disease usually begins with damage in the inner part of your arteries. Although acquired during childhood certain factors increase the risk;
-smoking
-high blood pressure
-high cholesterol
-diabetes
-unhealthy lifestyles
-age (the older you get, higher the risk)
-sex (men have greater risk)
-family history
-obesity (excess weight)

When the inner wall of the artery is damaged the plaques otherwise known as fatty deposits made out of cholesterol and other waste products accumulate at the site of the injury and begin a process known as atherosclerosis. This leads to blocked arteries which lead to heart attack.

Caption for picture: 'development of atherosclerosis'

http://www.mayoclinic.org/diseases-conditions/coronary-artery-disease/symptoms-causes/dxc-20165314

http://www.cardiackids.ca/CHD.shtml

Coronary Heart Disease

Benjamin Maglajac

Coronary Heart Disease

What is Coronary Heart Disease

According to the American National Heart, Lung and Blood Institute Coronary Heart Disease (CHD) is a disease where fatty deposits called plaque builds up on the inside of the coronary blood artery. The gradual build up of this fatty material inside an artery causes the flowing path of the blood to narrow and is called atherosclerosis (Figure 1). This condition then leads to hindering of proper supply of the heart with oxygen rich blood

 

Figure 1 (http://www.nhlbi.nih.gov/health/health-topics/topics/cad)

The Effects of CHD

Due to the decreased flow of blood towards the heart the heart muscle will not be sufficiently supplied with oxygen which makes it unable to work properly. Effects of that can be a pain in the chest called angina. Similar symptomes which can occur due to atherosclerosis in the coronary heart artery are arhythmiasin, problems with the rate or rithm of the heartbeat or heart attack which can lead to death. According to thrombosisadviser.com CHD is one of the most common causes of death in the US and Europe and its symptoms are causing 2.5 million hospitalizations every year.

Factors leading to CHD

The plaque causing CHD is made up of cholesterol and other waste substances. According to nhs.uk the build up of these waste substances inside the arteries is fostered by the following factors.

-         Family History of CHD

-          high cholesterol level in the blood: as cholesterol is one of the main components of plaque, a high concentration of it in the blood can cause it to build up on the inside walls of the arteries. However we also have to take the level concentration of the two different lipoproteins in the blood into consideration. Low density lipoproteins (LDL) transport cholesterol from the liver to the cells while high density lipoproteins (HDL). While LDL tends to build up and form plaque, a low level of HDL increases the risk of getting

-          high blood pressure:  high blood pressure damages the inner artery walls, which makes waste materials more likely to build up and form plaque

-          diabetes: diabetes, caused by high blood sugar levels increases the risk of plaque building up inside the arteries

-          smoking: carbon dioxide and nicotine in the smoke make the heart work faster and thereby increase the blood pressure. Furthermore the increase the risk of blood clots. Other chemicals in cigarette smoke can damage the lining of the coronary arteries, leading to furring of the arteries

-          lack of exercise: regular exercise helps to clear arteries. If there is a lack of exercise the risk of plaque building up increases

Correlations of CHD and our diet

Reading about the causes of CHD it becomes clear that many of these causes should be preventable with help of a healthy diet. The risk of getting diabetes for example can be lowered by renouncing foods that contain processed sugars such as sweets or sugary drinks. Instead it is better to eat a lot of fruits as a source of sugar. Furthermore it is important to know that saturated fats and trans fats (artificial fats) which are found in foods like cheese, cream or sausages increase the level of LDL in our blood and therefore increase the risk of CHD. So instead we should rather eat saturated fats which can be found in fish or nuts. Also, salt should be limited in a healthy diet as it raises the blood pressure and therefor increases the risk of getting CHD.

Although it seems very logic that a healthy diet can prevent some of the causes of CHD there is not much evidence actually proving this thesis. In order to find a direct correlation between diet and CHD scientists would have to collect the data of many people who would all have to stay on the same diet for a long time. It explains itself why it is hard to control the variables in such an experiment.

Sources

"Coronary Heart Disease - Causes ." Coronary Heart Disease. N.p., n.d. Web. 25 Jan. 2016.

"What Is Coronary Heart Disease?" - NHLBI, NIH. N.p., n.d. Web. 25 Jan. 2016.

"Heart Disease." Heart-healthy Diet: 8 Steps to Prevent Heart Disease. N.p., n.d. Web. 25 Jan. 2016.

CHD ( Coronary Heart Diseases)

Coronary Heart Disease

Ana Djurica

Biology HL

25.01.2016.

Mr. Youell

What is CHD?

• Coronary heart disease is a disease caused when a waxy substance called plaque builds up inside the coronary arteries, these arteries supply oxygen-rich blood to your heart muscle. Plaque building up in arteries is called atherosclerosis, it occurs over many years.

• Atheroclerosis

 

What are the risk factors?

• Risk factors include:  high blood pressure, smoking, diabetes, lack of exercise, obesity, high blood lipids, high blood cholesterol, family history poor diet, and excessive alcohol, among others. Other risk factors include depression.

What are the signs and symptoms? 

• The most common symptom of CHD is angina. Angina is often referred to as chest pain (chest discomfort, pressure, aching, burning). 

• Shortness of breath occurs when heart can't pump enough blood to satisfy the body. 

• Heart attack may be caused by a completely blocked coronary artery. 

How does a poor diet cause CHD?

• Eating well is also a challenge, when you're leading a fast lifestyle. Knowing what impact your diet has on your heart will help you improve your chances of avoiding potential complications: 
• FATS: Eat foods with unsaturated fats, reduce the amount of butter and shortening in your diet and replacing them with healthier oils such as olive or canola. Limiting your saturated fat intake to less than 7g daily and eating a maximum of 1g of trans fat a day are also recommended.
• SALT AND SODIUM: Too much salt increases blood pressure which is one of the risk factors. The Institute of Medicine recommends keeping sodium intake under 2,300 milligrams daily, which is approximately the same as 1 teaspoon of table salt, but people with heart problems should reduce their intake to 1,500 milligrams. In addition to salt, sodium-filled foods and condiments such as mustard, soy sauce and canned foods are also dangerous. 

Is there anything you can do to prevent CHD?

• Yes! There are numerous way you can do this! 
• Eat a healthy, balanced diet. Which means-low fat and high fiber. Lots of fresh fruit and vegetables and whole grain. And as little junk food as possible. 
• Be more physically active and keep a healthy weight.
• If you are a smoker, try quitting or at least reducing. 
• Reduce your alcohol consumption!
• Keep your blood-pressure under control. 

Sources:

• Wikipedia 
• NHC Choices

Factors leading to coronary heart disease (CHD)

What is CHD?

Figure 1- Image showing the location of the coronary
arteries and comparing a normal coronary artery
to one narrowed by atherosclerosis

Coronary Heart Disease is when our coronary arteries (arteries that supply our heart muscle with oxygen-rich blood) become more narrow due to a gradual build-up of fatty material within their walls (Figure 1). This condition is known as atherosclerosis and the fatty material is known as atheroma. Atheroma is also referred to as plaque.
Over time, our arteries can become so narrow that not enough oxygen-rich blood can flow through them to the heart. As a result, we can feel pain and discomfort called angina. On the other hand, if a piece of atheroma breaks off, a blood clot can form, blocking blood flow.

How does CHD develop?

From a young age, cholesterol-loaded plaque can start to deposit in the blood vessel walls. As we get older, the plaque builds up and results in the inflammation of the blood vessel walls as well as a higher risk of blood clots and heart attacks. The plaques release chemicals that encourage the process of healing but cause the inner walls of the blood vessels to be sticky. Other substances such as inflammatory cells, lipoproteins, and calcium then travel through our bloodstream and start sticking to the inside of the vessel walls.
Eventually, it is possible for a narrowed coronary artery to develop new blood vessels that form around the blockage to get blood to the heart. Even so, during times of increased stress or exercise, the new arteries may not be able to supply sufficient oxygen-rich blood to the heart muscle.

Causes of CHD

As well as the gradual build-up of atheroma, there are factors that can increase the risk of developing atherosclerosis. These include:

• Smoking- The chemicals in tobacco smoke harm our blood cells. They can damage the function of our heart and the structure and function of our blood vessels, therefore increasing our risk of atherosclerosis

• High blood pressure (hypertension)- Hypertension stresses our body's blood vessels causing them to clog and weaken. Additionally, it can lead to atherosclerosis and narrowing of the blood vessels making them more likely to block from blood clots. 

• High blood cholesterol level- When there is too much cholesterol in our blood, it builds up in the walls of our arteries, causing atherosclerosis. 

• Lack of regular exercise- Exercise increases circulation and helps clear arteries. Lack of regular exercise prevents this circulation and cleanup of arteries, increasing our risk of developing CHD.  

• Diabetes- High blood sugar levels increase the chance of buildup of plaque in our arteries, therefore leading to CHD.

• Obesity- Obesity leads to high blood pressure, high blood cholesterol, and diabetes, all of which increase our risk of CHD. 

• Family history of CHD

Preventing CHD

There are multiple ways of lowering the risk of developing CHD. Firstly, it is important to take into consideration the factors that increase the risk and prevent these. For example, it is important to regularly exercise, maintain a normal blood cholesterol level as well as a normal blood pressure, etc... Factors decreasing the risk of CHD include:

• Eating a healthy, balance diet- According to nhs.uk, it is recommended to eat a low-fat, high-fibre diet which should include a large amount of fruit and vegetables and whole grains. The amount of salt in the diet should be limited as too much salt will increase blood pressure. There are two types of fat: saturated and unsaturated. It is recommended to avoid saturated fats because they will increase the levels of bad cholesterol in our blood. As seen in Figure 2, sausages, butter, cream, cakes and biscuits are example of foods containing saturated fats. A balanced diet should include unsaturated fats which are found in nuts, seeds, avocados, and oily fish. 

• Reduce alcohol consumption

• Take prescribed medication

Figure 2- Foods containing unsaturated fats vs saturated fats 

Bibliography:

"Coronary Heart Disease - Causes ." Coronary Heart Disease. N.p., n.d. Web. 22 Jan. 2016.

"Hypertension." Cardiovascular Disease Risk Factors -. N.p., n.d. Web. 22 Jan. 2016.

"Cholesterol and Heart Disease." WebMD. WebMD, n.d. Web. 22 Jan. 2016.

"How Lack of Exercise Causes Heart Disease." LIVESTRONG.COM. LIVESTRONG.COM, 30 Oct. 2015. Web. 22 Jan. 2016.

Coronary Heart Disease

 Coronary Heart Disease (CHD, Coronary Artery Disease), happens when atherosclerosis affects the coronary artery leading to the heart.

Atherosclerosis is a condition in which there is an excess of a substance called plaque, which is mainly made from calcium, cholesterol, and fat, in the arteries causing a narrowing or blockage of the oxygen-rich blood's pathway. A variety of factors may lead to atherosclerosis including smoking, excess consumption of alcohol, diabetes, and obesity.
In 2013, CHD caused 8.14 million deaths around the world, being rated as the most common cause of death.

There has been a lot of debate regarding the factors leading to CHD, most of them being the dietary factors. While the risk of high consumption of alcohol (>100g/d) has been shown to lead to a higher risk of CHD than that of heavy smoking(The Bruneck Study), there appears to be an outlier in "the French Paradox". "Epidemiological studies indicate that the consumption of alcohol at the level of intake in France (20-30g per day) can reduce risk of CHD by up to 40%.", says a study conducted all around the world by S. Renaud.

For a long time we believed that saturated fat foods (meat, cheese, butter...) were the primary cause of CHD and related diseases, but recently that has been taken into a debate also, as now the light has been put on trans fats, and researchers are saying that saturated fat can be good in normal doses. Trans fats increase the low density lipoprotein level (LDL) and decrease the high density lipoprotein (HDL), which leads to the build up of plaque, as LDL is the main cause of plaque and HDL removes LDL.

As there are so many factors that affect the risk of getting Coronary Heart Disease, scientist have a very hard time determining exactly how much each factor contributes. For an instance, a person might have the genetic predisposition towards CHD but might also be smoker regularly consume excess alcohol, if so, researchers would have a hard time determining exactly which factor led to the development of CHD in that patient. Also, because there has been so much debate within the scientific community about many factors, and they seem to be coming up with something new or negating something previous regularly, it hard to know what to eat and what not to, as 10 different people will give you 10 different answers. For now, it seems that the safest thing to do is take everything in moderation, as even too much of a good thing can lead to consequences.



Other recources:
-http://www.nhlbi.nih.gov/health/health-topics/topics/atherosclerosis/
-http://articles.mercola.com/sites/articles/archive/2015/08/31/saturated-fats-heart-disease.aspx
-http://www.acaloriecounter.com/diet/saturated-fat-trans-fat/
-http://www.heart.org/HEARTORG/Conditions/Cholesterol/AboutCholesterol/Good-vs-Bad-Cholesterol_UCM_305561_Article.jsp#.VqNiYBUrLIU

-

Coronary Heart Disease (CHD) - Yoonsik Park - January. 22. 2016

Factors leading to 

Coronary Heart Disease (CHD)

What is CHD?

The British Heart Foundation defines it as when fats periodically build up in the walls of the coronary arteries (arteries that pump oxygen-rich blood to the heart) and narrowing them. 

The flow of blood is slowed down or blocked, so the heart may not get enough oxygen-rich blood into it, which would lead to heart attack. According to nhs.uk, it is the leading cause of death worldwide.

Atherosclerosis - is the technical term for a disease in the arteries in which fatty materials build up on the inner walls of the arteries; according to mayoclininc.org 

(picture 1 : http://www.nhlbi.nih.gov/health/health-topics/topics/cad )

As it can be seen in (Picture 1), as the plaque, or fatty substances, builds up in the coronary artery, it narrows it down, getting in the way of normal blood flow. 

(picture 2 - https://upload.wikimedia.org/wikipedia/commons/6/6d/Blausen_0259_CoronaryArteryDisease_02.png) 

Picture 2 is a more close-up, sideways view of the fatty substances and plaque buildup in the coronary arteries. As you can see, the channel for blood to flow is significantly narrowed. What causes CHD? Let us find out. 

Causes of CHD

Fatty substances are build up in your coronary arteries.

Some factors that may cause the buildup of fatty substances are

• Smoking
• High blood pressure
• High blood cholesterol
• Diabetes (High levels of sugar in the blood)
• Obesity, being overweight
• Diet 

1) Smoking - cigarettes are known to be the cause of many health problems. Cardiovascular health-wise, it increases the chance of CHD because it increases blood pressure, raising the risk of blood clotting. It also triggers plaque buildup in the arteries. 

2) High Blood Pressure - according to Sameer A. Sayeed, Doctor in Cardiology, having high blood pressure causes pressure on the arteries, which damages the walls, making it easier for fatty substances to build up on it. 

3) High Blood Cholesterol(fatty, wax like substance) - there is bad cholesterol (low-density lipoproteins, LDL) and there is good cholesterol (high-density lipoproteins, HDL). High levels of LDL will cause buildup in the arteries, and increase your chance of getting CHD. HDL aids in the removal of cholesterol from the arteries, so it is referred to as 'good cholesterol.' High blood cholesterol is usually from being obese, which means there is a problem in your diet, and exercise levels. 

4) Diabetes - high blood sugar level increases the chance of plaque buildup in your arteries, increasing the chance of CHD. 

5) Obesity, Overweight (in adults) - obesity is connected to many causes of CHD such as high blood pressure, high blood cholesterol, and diabetes.

6) Diet- this is important, as in many cases it can prevent 4 of the causes of CHD mentioned above (high blood pressure, high blood cholesterol, diabetes, and obesity) 

Unhealthy diet may lead to CHD. If you eat too much foods (creams, butter, popcorn, sweets, etc) that have high saturated and trans-fats(artificial), and LDL, you may want to change your diet. You want to eat healthy (fruits, vegetables, meat).

However, although there seems to be a correlation of the causes mentioned above and coronary heart disease (meaning that there seems to be a connection), finding exact evidence on the causes of CHD in humans may be hard because it is difficult to conduct experiments on humans where conditions are exactly measured. 

For example, if a research team wanted to see the relationship of a person's diet and CHD, it is hard for a human to stay on a very strict diet. Also there may be other causes that are not taken into account.  

Effects of CHD

The narrowing of the coronary arteries can cause heart damage and heart attack. 

If you experience chest pain, nausea, irregular breathing, and or shortness of breath, you may want to go to the doctor and get checked up. 

Like the public service advertisement (picture 3) you should quit smoking. Also you want to exercise more, eat less junk food and eat healthier. 

(Picture 3 - https://upload.wikimedia.org/wikipedia/commons/thumb/8/87/Exercise,_Smoking_and_Coronary_Heart_Disease.png/280px-Exercise,_Smoking_and_Coronary_Heart_Disease.png)

We should all be aware of the causes and symptoms of CHD, and try to avoid unhealthy habits if we want to live a healthy, long life. 

Factors leading to Coronary Heart Disease (CHD)

CHD is a coronary heart disease where plaque builds up inside someones coronary arteries, slowing the flow of Oxygen and blood to the heart. This is a slow process that takes many years. Heart attacks may occur due to this condition. CHD is both genetic as well as due to unhealthy environment and living. CHD is not only one type of heart disease but it is in fact many different types falling under one category. CHD is a deformity or malformation of the heart that children are born with. This is an issue because 1% or more of the worlds children are affected by CHD that is 8 out of every 1,000 kids who will have a CHD disease. 

There are many different things you can do to help prevent this from occurring. By eating the right foods such as...

• Oily fish - high in omega, Ex. Salmon, Tuna, Trout, etc.
• Vegetables - Ex.broccoli, cabbage, carrots, etc. 
• Fruit - Ex. apples, bananas, oranges, etc. 
• Whole grains - Ex.oatmeal, brown rice, Corn tortillas, etc.  

To decrease your CHD risk you should NOT be or have...

• High blood pressure
• High Cholesterol
• Diabetes
• Genetic CHD
• Obese 
• An active smoker

It is shown that men are more at risk of developing CHD at a younger age than women. Also if you are older you have a higher risk of developing CHD.

Bibliography

"What Is Coronary Heart Disease?" - NHLBI, NIH. N.p., 23 Oct. 2015. Web. 22 Jan. 2016. <http://www.nhlbi.nih.gov/health/health-topics/topics/cad>. 

"How To Prevent and Control Coronary Heart Disease Risk Factors." - NHLBI, NIH. N.p., n.d. Web. 22 Jan. 2016. <http://www.nhlbi.nih.gov/health/health-topics/topics/hd/prevent>.

"CHD." MedicineNet. N.p., n.d. Web. 22 Jan. 2016. <http://www.medicinenet.com/script/main/art.asp?articlekey=15370>http://www.medicinenet.com/script/main/art.asp?articlekey=15370

Factors leading to coronary heart disease (CHD)

What is CHD?

Coronary heart disease (CHD) is the blocking of the arteries that directly supply the heart muscle, with it's necessities such as oxygen rich blood which the cells need in order to function. Without this oxygen rich blood the cells cannot function hence, they die. In the heart we have 2 main coronary arteries, one on the right, the other on the left. They then branch off into many smaller arteries which then provide the heart with the oxygen. Coronary heart disease is usually caused by a condition called atherosclerosis, which occurs when fatty material and other substances form a plaque build-up on the walls of your arteries. A diet high in fat and cholesterol can cause a deposit of plaque to form on the inside of the artery, making it narrower and preventing blood supply. As a result of these we can feel pain otherwise known as angina.

How does CHD develop? (The process)

1. Your arteries are shaped like hollow tubes and normally, when healthy their inner walls are smooth and elastic, as shown in Figure 1.
2. CHD develops at a very young age; before a child reaches their teen years the blood vessel walls begin to show streaks of fat.

Figure 1: The process of CHD 

1. As you get older the far on the walls builds up which causes injury to the blood vessel. The cells attempt to heal the walls by releasing chemicals which make the walls stickier so when other substances like proteins, cellular waste products etc. flow through they stick to the walls. However the fat and these other substances then begin forming a material known to us as the plaque. (See Figure 1)
2. As time passes the plaques on the walls develop to different sizes. A plaque is soft to the touch however has a hard cap layer around the outside. If broken, and the inner tissue is exposed platelets (particles in the blood which prevent clotting) travel to the area.
3. If this occurs the arteries narrow even more.

It is possible for a narrowed artery to produce new blood vessels which form around the blockage and allow the blood passage into the heart. Regardless, during increased exercise activity the newly formed arteries still may fail to supply a sufficient amount of oxygen needed.

Causes of CHD?

Certain factors which may be a benefactor to the destroyed inner walls of the artery are;

• smoking (chemicals in the tobacco harm our blood cells)
• high levels of fats/cholesterol in the blood (when there is too much cholesterol in our blood it builds up in the walls of the arteries)
• high blood pressure (also known as hypertension; it stresses our blood vessels which causes them to clog)
• high sugar in the blood (diabetes/insulin resistance; increase the chances of the build up of plaque)
• lack of exercise (when we exercise our circulation increases which clears the arteries)
• family history of CHD

How do we prevent it?

There are multiple ways in which to prevent or delay the risk of developing CHD. Some of these include lowering your blood pressure and cholesterol levels. This is achieved through numerous ways.

One of the key ones is managing and withholding a healthy and balanced diet. A low fat, high fibre diet is the way to go. It should include a variety of fruits and vegetables as well as whole grained goods. Limits should be put on spices such as sat as sat increases blood pressure.

We enjoy two types of fat; saturated or the ''bad fat'' and unsaturated, the ''good fat''. To decrease the risk of CHD, saturated fats should be avoided as they increase cholesterol levels in your blood. Some foods with high saturated fats are; butter, cream, hard cheese, cakes, palm oil, meat pies etc. The unsaturated fat, or the ''good'' fats are found in foods like oily fish, avocados, nuts and seeds, vegetables oils etc.

Although it is important to have both, a decrease in the intake of sugar will also decrease the risk of diabetes which dramatically increase the development of CHD.

Bibliography:

http://www.nhlbi.nih.gov/health/health-topics/topics/cad/causes

http://my.clevelandclinic.org/services/heart/disorders/coronary-artery-disease/caddevelop

http://www.nhs.uk/Conditions/Coronary-heart-disease/Pages/Prevention.aspx