2023-08-30 19:03:07
Newly Discovered Stem Cells in Thymus Provide Insight into Immune Diseases and Cancer
By [Author]
Slowly but surely it is becoming increasingly clear why we have a thymus in the first place: the newly discovered stem cells could even be important targets to fight immune diseases and cancer.
The thymus is an organ in the chest. It lies just behind the sternum and close to the heart. The organ is not much bigger than a walnut and appears to do little in adults. That is why the thymus – at least in adults – was seen as a rather useless organ. That is why surgeons had a knack for simply popping out the thymus – which can often get in the way during heart operations, for example. Recently, however, researchers came back to that. If the thymus is removed, the risk of death and cancer certainly doubles. And new research now shows why the sweetbreads are really indispensable.
The sweetbreads
The thymus is especially active in children, until puberty. Then it shrivels. The organ is particularly important for the immune system. In children, for example, it is an important producer of immune cells (the so-called T cells), which are crucial for fighting diseases. It also ensures that memory cells are created. If you become ill from a bacteria or virus that you have already dealt with in the past, your body will produce antibodies more quickly, so that you do not become seriously ill from the same bacteria or virus time after time.
Defense system
In short, the thymus plays an important role in building a good immune system. After puberty, your immune system is strong enough. The sweetbreads then become less important, or so was the general assumption. But nothing could be further from the truth, as researchers now prove once again.
The structure of the sweetbreads
The thymus is known to have a unique and complex 3D structure. This consists of two lobes. Each lobe consists of smaller lobes. The outer layer of the thymus consists of epithelial cells found throughout the organ and around the so-called thymocytes (an immune cell present in the thymus before it transforms into a T cell). Forming a network.
Self-renewing stem cells
What researchers have now discovered is that the thymus also harbors self-renewing stem cells. These stem cells give rise to the aforementioned epithelial cells, which instruct the thymocytes to become T cells. This suggests that the thymus plays an important, regenerative role after childhood, which could be exploited to strengthen the immune system.
Two locations
During experiments, the researchers examined these self-renewing stem cells based on the expression of specific proteins. In this way, the team discovered the areas where the stem cells are clustered. This happens in two locations in the thymus: on the outer layer and around the blood vessels in the central part.
Genes
Using state-of-the-art techniques, the researchers then discovered that the self-renewing stem cells express a variety of genes. And that’s interesting. This means that they can give rise to many cell types that were previously not believed to have a common origin. They can develop into epithelial, muscle, and neuroendocrine cells, highlighting the importance of the thymus in the regulation of hormones.
Regeneration
The researchers isolated the stem cells in a petri dish, which further revealed the function of the stem cells. For example, they showed that all complex cells in the epithelium could be produced from a single stem cell. This also shows the far-reaching regenerative capacity. “It’s actually quite paradoxical that stem cells in the thymus – an organ that gets smaller as we age – regenerate just as much as those in the skin – an organ that replaces itself every three weeks,” said researcher Roberta Ragazzini. “The fact that the stem cells give rise to so many different cell types points to many fundamental functions of the thymus, even in adulthood.”
Useful
The findings show conclusively that the thymus is anything but a useless organ. In fact, it is much more functional than doctors and scientists ever thought possible. “This research represents a critical shift in our understanding of why we have a thymus that is capable of regeneration,” said study co-author Paola Bonfanti. “There are so many important implications of stimulating the thymus to produce more T cells. Think of helping the immune system to respond to vaccinations in the elderly or improving the immune response in cancer.”
The newly discovered self-renewing stem cells may represent a new target to better understand the causes of immune diseases and cancer and to strengthen the immune system. Research into the organ that is considered unimportant therefore continues unabated. For example, the researchers now plan to study the stem cells of the thymus over a lifetime. They also hope to discover how the stem cells can be manipulated so that they may be useful in future treatments for various diseases.]
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