Human Longevity: What are Senescent Cells?

Have you ever thought about or wanted to live forever or longer than normal? Then you are not alone. Humans have been figuring out ways to live longer since the beginning of humanity. As we are moving into the future our lifespan is increasing more and more. What is making us age in the first place? One cause is thanks to senescent cells.

What is Human Longevity?

Ever since humanity was just starting, people have been finding ways to live longer. Nowadays people are living longer than before because of advances in healthcare and sanitation. Scientists have started to focus away from increasing humans lifespans to increasing our “healthspan”, which is a period of life when one is healthy. Even though humans are living for longer yet they spend most of their life, not being healthy. Therefore scientists are focusing on humans healthspans which could increase their lifespans.

What are Senescent Cells?

Every person’s body consists of cells which are the structures of a person’s body that carries out specialized functions. In each cell, there are chromosomes that define the role of the cell in a person’s body. Cells reproduce to make more cells by dividing themselves in half and copying over the chromosomes.

Image of a cell reproducing

When the cell splits, a part of the chromosome gets destroyed. In order to counter this, the body has a protection cap at the end of each chromosome. This is called a Telomere. Telomeres are just like aglets in that they protect chromosomes as aglets protect shoelaces.

Image of a Chromosomes and their Telomeres

The same as the chromosomes the telomeres also get shorter every time the cell reproduces. When the cell has split around 40 to 50 times, it stops reproducing so it won’t damage the cell’s chromosome. However, when a cell does not stop reproducing and its chromosomes start getting destroyed, it becomes senescent. A senescent cell does not go away or do anything useful for the body.

Image of a Senescent Cell

In order to counter these senescent cells have a programmed process called apoptosis which is like self-destruction when a cell turns senescent. Senescent cells are also removed by the immune system in the body. However as the body grows older, the immune system gets weaker and increases the number of senescent cells escaping the process and they start building up.

Image of the Immune System

Damages from Senescent Cells

A senescent cell alone does no damage or anything useful for the body. As a person gets older they accumulate more senescent cells in their body. A lot of senescent cells in a person’s body can start to be a threat to a person’s health. The senescent cells can also block some of the bloodstreams causing even more disease. They cause problems such as degrading tissue functions, increase the levels of chronic inflammation, and even increase the risk of cancer.

What are scientists doing now?

Scientists are looking for ways to stop the senescent cells from creating major damages in the body. Scientists have created a drug called Senolytics which focuses on destroying senescent cells from the body in order to reduce inflammation and improve tissue functions. Scientists have tried the Senolytics on a mouse which destroyed 80% of the senescent cells in the mouse’s body without destroying any of the healthy cells. It caused the mouse to be more active than other mice of the same age and also made it live 30% longer than normal. Scientists are trying to get this drug approved for clinical trials on humans.

Key Takeaways

  • Humans are living longer than ever before due to advances in healthcare and sanitation. Focusing on increasing our healthspan will cause our lifespan to increase.
  • Senescent cells are cells that have died but still stay in the body. Alone the senescent cells are harmless but when there are a lot of them, then it starts to become a problem. The senescent cells can cause problems such as blocking bloodstreams and damage tissues.
  • In order to solve the problem of senescent cells, scientists have created Senolytics which can get rid of senescent cells that has shown promising results in research.
  • Human longevity is in a pretty early stage of its development but in the future, these technologies might be available to all humans. Possible one day humans could live forever.

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