A recent study might provide answers to a long-standing question about why a vital immune organ in our bodies diminishes in size and effectiveness as we age.
A WEHI study might provide answers to a long-standing question about why a vital immune organ in our bodies diminishes in size and effectiveness as we age.
The thymus is crucial for maintaining good health as it generates specialized immune cells that help combat infections and cancer.
In a groundbreaking discovery, researchers have identified new cell types that contribute to the aging process of the thymus — important findings that may lead to methods for restoring its function and preventing our immune system from declining with age.
Key Highlights
- The thymus is fundamental to our immune defense; however, it shrinks and becomes less effective as we age. The cause of this decline has puzzled scientists for many years.
- For the first time, this study has visualized how two specific cell types accelerate the aging process, leading to diminished function and regenerative capacity of the thymus over time.
- The results could pave the way for strategies to halt the aging of the thymus and importantly, develop techniques to restore immunity in at-risk populations in the future.
T cells, also called T lymphocytes, are a type of white blood cell that plays an essential role in our immune response. They are critical for detecting and reacting to pathogens, such as viruses and bacteria, and for eliminating infected or cancerous cells.
The thymus, a small but vital organ located behind the breastbone, is the sole organ capable of producing T cells.
Interestingly, the thymus is the first organ to diminish in size as we age. During this process, areas responsible for T cell production are replaced by fatty tissue, which reduces T cell production and weakens the immune system.
Although the thymus can heal from damage, researchers have not yet determined how to activate this ability to enhance immunity in aging individuals.
Professor Daniel Gray, the head of the WEHI Laboratory, stated that the recent findings published in Nature Immunology could shed light on this mystery that has puzzled scientists for years.
“The creation of new T cells significantly decreases after puberty, regardless of one’s fitness level. By the time one reaches 65, the thymus has nearly stopped functioning,” Prof. Gray said.
“The deterioration of the thymus makes it increasingly difficult for the body to fight off new infections, cancers, and manage immunity as we age.”
“This is why adults with weakened immune systems — such as those recovering from cancer treatments or stem cell transplants — tend to take much longer than children to regain their strength.”
“These adults may require years to restore their T cells, or in some cases, they may never fully recover, which leaves them at a greater risk of serious infections for the rest of their lives.”
“Investigating how to revive thymic function is crucial for developing new therapies that could improve outcomes for these at-risk patients and ensure a steady production of T cells throughout our lives.”
The recent study, which is a collaboration involving researchers from the Fred Hutch Cancer Center in Seattle and the Memorial Sloan Kettering Cancer Center in NYC, offers vital new insights that could help achieve this aim.
“Our findings present a novel perspective for thymic regeneration and immune restoration, potentially uncovering ways to enhance immune function in vulnerable individuals in the future,” Prof. Gray remarked.
Scarring Effects
Utilizing advanced imaging techniques at WEHI’s Centre for Dynamic Imaging along with animal models, the research team uncovered two new cell types that contribute to thymic dysfunction.
These cells were only found in the dysfunctional thymus of older mice and humans and were observed to form clusters around T cell growth zones, impairing the organ’s ability to produce these crucial immune cells.
In a pioneering discovery, the researchers identified that these clusters also create ‘scars’ in the thymus, obstructing its capacity to regenerate after injury.
Dr. Kelin Zhao, who spearheaded the imaging studies, explained that these findings illustrate how the scarring process serves as an obstacle to thymic function and regeneration.
“While much of the research on thymic loss has focused on the shrinking aspect, we’ve demonstrated that internal changes within the organ also affect its functionality as it ages,” Dr. Zhao stated.
“By observing these cell clusters and understanding their role in the loss of thymic function, we’ve accomplished something unprecedented, largely thanks to the remarkable advanced imaging tools at WEHI.”
“This understanding allows us to explore the possibility of targeting these cells therapeutically in the future, aiming to reverse the aging process of the thymus and enhance T cell function in older adults. This is the objective our team is striving to achieve.”
