Have you ever wondered what happens to the tiny cells inside our bodies? Sometimes, just like us, these cells 'die' when their time is up. This is what we call 'cell death' in medicine. Although this is a bit scary to hear, it is actually essential for the healthy survival of our bodies in many cases. So today, let's talk about what this cell death is, how it happens, and how it affects our bodies.
What are cells? Let's first understand that!
Okay, before we talk about 'cell death', let's look at what these 'cells' are. Imagine that our body is a big building, and cells are like the smallest bricks that make up that building. In fact, you can't even imagine, there are more than 30 trillion cells in our body! All of these cells come together to form our tissues and organs. Generally, there are three main parts to a cell:
- Cell membrane: This is like the protective fence, or gate, of the cell. It is what decides and controls what can enter and leave the cell.
- Cytoplasm: This is the jelly-like liquid part inside the cell. The production of proteins needed by the cell and many important chemical processes that occur inside the cell take place in this cytoplasm.
- Nucleus: This is the 'control center' or 'brain' of the cell. Our genetic information, that is, DNA (`DNA` - Deoxyribonucleic acid), is mainly contained within this nucleus. The nucleus also makes RNA (`RNA` - Ribonucleic acid) . This `RNA` copies the information in `DNA` and helps cells make various proteins that they need to function and grow.
Now you have a rough idea of what a cell is.
So, what is this cell death?
Simply put, cell death is when the cells in our body stop functioning and die when they have finished their work or are damaged for some reason. The cells in our body are not just formed. They are constantly dividing and making new cells. We call this 'cell division' (`Mitosis`) . According to experts, a healthy human cell can divide in this way about 50-60 times. After that, the cell ages and dies.
Our bodies are constantly making new cells to replace old, damaged, and dying cells. It's like getting rid of old stuff and bringing in new stuff.
This natural cell death helps keep our bodies healthy and functioning properly. However, problems arise when this cell death does not occur as expected, or when cells that are not supposed to die start dying.
Why do our cells die? What are the reasons?
There are various reasons why cells die. Some are natural, some are not. Let's look at the main reasons:
- Some cells die while they are growing , before they are fully formed.
- When old cells reach the age where they can no longer divide, that is, when their lifespan has ended, they die. This is a normal process.
- If there are cells that are damaged beyond repair in some way, they die naturally. They can't be stored in the body like garbage.
- Disease, injury, toxins, and some treatments can also damage cells and cause them to die.
Who is at risk of cell death?
In fact, cell death affects us all – and it’s often a good thing. It’s amazing, your skin sheds about 40,000 dead cells a day! The top layer of our skin, called the epidermis , is constantly producing new skin cells to replace these dead cells. In other words, if this cell death didn’t happen, we wouldn’t have healthy skin.
What are the main types of cell death?
Depending on the way cells die, it can be divided into three main types:
1. Apoptosis - Planned cell death
2. Autophagy - cellular recycling and death
3. Necrosis - Cell death caused by accidents
Let's now talk about each of these types in a little more detail.
1. Apoptosis or programmed cell death
Apoptosis is a naturally occurring, planned cell death . In this process, cells destroy themselves. After a cell has divided a maximum number of times, when it reaches a point where it can no longer divide, it dies through this process (Apoptosis). This planned cell death is very healthy and expected for our bodies.
Consider this example. When a baby's fingers first form in the mother's womb, they are connected to each other by a thin layer of skin between them. Just like the skin between the toes of a duck's legs. But as the baby grows, this process of ``Apoptosis'' causes the unnecessary cells between those fingers to die in an orderly manner. That's when the fingers separate nicely and form five separate fingers. Imagine, what if this ``Apoptosis'' didn't happen properly? Then the skin between those fingers could remain as it is. We call that condition ``Syndactyly'' . See, sometimes it's important for these cells to die.
`(Apoptosis)` is a process that occurs constantly. This is what removes old, damaged cells from our bodies, making way for young, healthy cells to replace them. However, if for some reason this planned cell death does not happen properly, those old, damaged cells start dividing uncontrollably. This is a major reason for the development of tumors and cancers.
Also, sometimes due to errors in cell programming, cells that are not supposed to die can also die through this process of ``Apoptosis''. For example, in people with diseases such as Parkinson's disease, Huntington's disease , or Alzheimer's disease, the nerve cells (` `Neurons``) in the nervous system die excessively. This premature cell death can affect thinking and movement.
2. Autophagy or cellular recycling
Autophagy is another type of programmed cell death. But this one is special. It usually occurs when the body is under some kind of stress, tension, or lack of food. It is like a ``recycling system`` that occurs at the cellular level in our body.
In the process of ``Autophagy`` (which means ``self-eating''), a cell ``eats'' its own old, damaged proteins, or other unwanted parts of the cytoplasm. It then recycles the broken-down parts and supports the cell's vital functions. It's like getting rid of old things in your house and taking the usable parts and building something new.
This process of ``Autophagy'' is sometimes very useful.
- Our immune system helps destroy things like viruses and bacteria that cause infections.
- It can also help prevent healthy cells from becoming cancer cells.
- It is believed that this can also help prevent other problems such as heart disease .
But, on the other hand, if you have cancer, this process of ``(Autophagy)`` can be detrimental. Because, this recycling process provides cancer cells with extra nutrients, which may accelerate their growth. Not only that, but these recycled cells can also interfere with the destruction of cancer cells by cancer treatments.
Some people try to stimulate this process of ``Autophagy'' by restricting calories or fasting, and thus producing young, healthy cells. However, there is not yet enough scientific evidence to say that artificially inducing ``Autophagy'' in this way is effective. Also, strict dietary restrictions can sometimes be harmful to health.
3. Necrosis or sudden cell death
Necrosis is not something that is planned like the previously mentioned `(Apoptosis)` or `(Autophagy)`. It is a sudden or unexpected cell death. This causes tissue death . Imagine, you have a severe injury to your arm or leg. At that time, those injured cells are damaged, and their contents leak out, which can also damage healthy cells around them. This causes swelling, redness, pain, and other things that can damage and die.
The important thing is that, although doctors can remove this dead tissue, the tissue death caused by ``necrosis`` is ``irreversible``.
This condition, ``Necrosis,'' can also occur due to a decrease in blood supply and oxygen supply to some parts of the body. ``Necrosis'' occurs because the cells do not receive blood, oxygen, and nutrients when we die.
Some other causes of `(Necrosis)` are:
- Accidents and serious injuries (`Traumatic injuries`).
- Autoimmune diseases .
- Bacteria, viruses, and fungi that cause infections.
- Use of poisons, toxic substances and illegal drugs.
- Cancer treatments such as radiation therapy .
Types of Necrosis
There are several types of `(Necrosis)` depending on the cause and the part of the body affected. Some of the most common types are:
- Avascular necrosis or osteonecrosis (death of bone tissue)
- Gangrene ( death of skin tissue)
- Pulp necrosis ( death of the pulp of the tooth)
What is Activation-Induced Cell Death (AICD)?
This is a complicated topic, but it's good to know in simple terms. Activation-induced cell death (AICD) is a potential complication of the development of a cancer treatment called chimeric antigen receptor (CAR) T-cell therapy . It occurs when T-cells, a type of white blood cell that helps kill cancer cells, die prematurely.
In `(CAR) T-cell therapy`, doctors do something like this:
1. Leukapheresis is a procedure that removes unduly increased white blood cells (including T-cells) from the patient's blood.
2. Then these T-cells are activated in a laboratory and tried to grow them further.
3. New genetic information is added to these lab-grown T-cells, changing them so that they can seek out and destroy cancer cells.
4. Finally, the modified T-cells are reintroduced into the patient's bloodstream. They then seek out and destroy cancer cells.
But, unfortunately, when these T-cells are activated and grown in the lab, sometimes this ``AICD'' cell death can occur. Then, the number of modified T-cells available to fight cancer decreases.
What we need to remember from all this (Take-Home Message)
Although the word 'cell death' may sound a bit scary, now you know that this is a process that occurs naturally in our bodies most of the time and is essential for our healthy survival .
- A programmed cell death called apoptosis removes old, damaged cells and makes way for young, healthy cells.
- Through a process called autophagy , cells recycle their parts and work more efficiently.
- However, cell death from accidents such as necrosis is dangerous and can cause permanent tissue damage.
- Also, sometimes even `(Apoptosis)` and `(Autophagy)` can contribute to diseases like cancer.
However, our bodies are always busy repairing damaged cells and replacing those that die. Therefore, it is important to be aware of this process. If you have any questions or concerns about this, don't hesitate to talk to a doctor.
` Cell death, cells, apoptosis, autophagy, necrosis, body function, cell division
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