4 days to eliminate aging! This immune cell impresses scientists

If aging is a disease, then the cause lies in senescent cells
.

This was said by Professor
David A.
Sinclair, director of the Institute for the Biology of Aging at Harvard Medical School.
As one of the top "traffic stars" in the anti-aging industry in the United States, he was selected as one of the "Top 100 Most Influential People in the World" by Time magazine in 2014
.

Three features of cellular senescence include: irreversible growth arrest, apoptosis resistance, and a multifaceted secretory phenotype
.
Scientists believe that if a cell has all three characteristics at the same time, it is a senescent cell
.
Senescent cells are the zombie cells in our bodies (Source: Nature by Paweł Jońca)

Senescent cells

With the progress of biological research, the key role of senescent cells in the human aging process has gradually been valued
.

First, the number of senescent cells increases
with age.
Secondly, senescent cells appear
in the pathological process of many age-related diseases.

For example, idiopathic pulmonary fibrosis has senescent lung epithelial cells, atherosclerosis has senescent vascular endothelial cells, and visceral fat also has a large number of senescent cells
.

The accumulation of senescent cells is a key feature of many diseases, and removing these cells can significantly improve health
.
As a result, targeted removal of senescent cells, known as senolytic therapy, began to emerge as a promising anti-aging idea
.
Amazon CEO, Jeff Bezos, has been investing in
senescent cell clearance therapy for years.

However, most of the drugs currently involved in Senolytic therapy inhibit the anti-apoptosis pathway and may increase off-target effects on healthy tissue cells, that is, cause accidental injury
.

At the same time, scientists from the University of California, San Francisco, recently published an article in Science, found that "senescent cells" that express specific key markers in healthy and young tissues are not
useless.
They can sense inflammatory stimuli and promote stem cell regeneration
.

Therefore, the safe and precise removal of senescent cells is the key
to the implementation of Senolytic therapy.

iNKT cells

In 2021, Bhushan and other scientists announced in the journal Cell's "Med" that they had discovered the body's natural anti-aging cells: Invariant natural killer T cells (iNKT cells), an immune cell
with the ability to eliminate senescent cells.

Previously, due to the low lethality of foreign pathogens, iNKT cells have always been regarded as incompletely developed immune cells, and their status in immune cells is "embarrassing"
.
However, the new findings suggest that it is closely
related to senescent cells.

Studies have found that due to factors such as age and obesity, the number and activity of iNKT cells are greatly reduced, resulting in an increase in senescent cells in the body, which in turn leads to the occurrence
of chronic diseases.

Therefore, the researchers came up with the idea of reactivating iNKT cells by injecting lipid antigens to eliminate senescent cells
.

In the first group of mice, the researchers used high-fat diet-induced obesity mice as a mouse model
for Progeria.

As a result, in just 4 days, the reactivated iNKT cells cleared senescent cells
from the mice.
The mice's metabolic indicators such as blood sugar, insulin levels, and insulin sensitivity improved and returned to the level of
young, healthy mice.
At the same time, compared with current Senolytic drugs, iNKT cells have nearly 100% more senescent cell clearance and aging reversal ability
.

In the second group of mice, the researchers used bleomycin-induced idiopathic pulmonary fibrosis (IPF) mice, a fatal respiratory disease that is somehow terminal
.

In the same only 4 days, iNKT cells cleared senescent cells from the lungs of mice, inhibited the degree of lung fibrosis, and increased the survival rate of these "terminally ill" mice by nearly 50%.

Finally, cytotoxicity assays showed that iNKT cells were toxic
almost exclusively to senescent cells in humans.
Unlike existing Senolytic drugs, iNKT cells do not accidentally injure healthy cells
.

Not only that, iNKT cells will die after completing the mission, and they really do "everything is done, hiding and famous"
.

Because senescent cells accumulate in a variety of tissues, chronic diseases occur.

He speculates that activating iNKT cells will be useful in treating a wide variety of chronic diseases
.

Therefore, iNKT cells are expected to be popular candidates
for anti-aging immune cell therapy.