Tag Archives: senescent cells

New vaccine could remove “zombie” cells that cause aging

Researchers in Japan have developed a new vaccine that they argue could remove senescent cells, also known as zombie cells, which are usually associated with aging and several diseases. Mice administrated with the vaccine showed decreased levels of the zombie cells, creating antibodies that attach to the cells and removing them. 

Image credit: Pixabay (Creative Commons).

Professor Toru Minamino of Juntendo University and a team of researchers identified a protein in senescent cells in humans and mice, then created a peptide vaccine that targets it. When applied, the body creates antibodies that attach themselves to the cells, which are then removed by white blood cells that adhere to these antibodies, Minamino told The Japan Times.

The researchers first administered the new vaccine to mice with arterial stiffness, reporting positive results. Plenty of accumulate zombie cells were removed and areas affected by the disease were reduced. Then they applied the vaccine in older mice, in which the progression of age proved to be slower compared to mice who hadn’t been vaccinated. 

“Senolytic vaccination also improved normal and pathological phenotypes associated with aging, and extended the male lifespan of progeroid mice,” the researchers wrote in their paper in the journal Nature Aging, reporting on the results. “Our results suggest that vaccination targeting seno-antigens could be a potential strategy for new senolytic therapies.”

Understanding zombie cells

A wide array of stress factors can harm our body cells. Ideally, these are removed through our immune system through a process called apoptosis. But as we get older the body isn’t as effective at removing dysfunctional cells. This can contribute to an already weakened immune system and less efficient biological processes, triggering disease. 

Over the years, researchers have been exploring whether better management of senescence cells can revitalize aging tissues and increase active years of life. These cells are quite unique as they eventually stop multiplying but don’t die when they should. Instead, they continue releasing chemicals that can cause inflammation – like a moldy fruit affecting the rest. 

The older we are, the more zombie cells we have in our body. And since our immune system is less efficient, these cells accumulate and affect healthy ones. This can affect our ability to cope with illness or stress, recuperate from injuries and even learn new things, like another language – as zombie cells also degrade our brain’s cognitive functions. 

Senescent cells have been linked with a set of age-related conditions, such as cancer, stroke, Alzheimer’s disease, diabetes, cardiovascular disease and even eyesight problems. Researchers have been looking at these cells since early 1960s, with investigations currently being done on a potential connection with cytokine storm induced by Covid-19. 

Back in May, researchers at the University of California, San Francisco (UCSF) reported having discovered how immune cells naturally clear the body of zombie cells. Their finding, based on laboratory experiments in mice, could open the door to new approaches and strategies to treat age-related diseased with immunotherapy, they argued. 

The study behind the new vaccine was published in the journal Nature Aging. 

Shown here are two aged rats. The one in the back received a peptide treatment which destroys senescent cells while the one in the front didn't. The latter mouse is in poor health as evidenced by the missing fur. Credit: Peter de Keizer

Drug reverses aging in mice. The rodents saw increased stamina, better organ function, and restored fur

Dutch researchers from the Erasmus University Medical Center boast promising results with a new drug meant to reverse the effects of aging.Tests performed on mice suggests the drug is effective at restoring stamina, coat of fur, and even some organ function.

Shown here are two aged rats. The one in the back received a peptide treatment which destroys senescent cells while the one in the front didn't. The latter mouse is in poor health as evidenced by the missing fur. Credit: Peter de Keizer

Shown here are two aged rats. The one in the back received a peptide treatment which destroys senescent cells while the one in the front didn’t. The latter mouse is in poor health as evidenced by the missing fur. Credit: Peter de Keizer

As we age, some cells begin to change their internal structure and ability to keep homeostasis. One component of aging is the damage caused by senescent cells, which are cells which have stopped dividing but which have not destroyed themselves as they should have following programmed cell death. Senescent cells secrete abnormally large amounts of some proteins that are harmful to their neighbours, stimulating excessive growth and degrading normal tissue architecture. These cells have also been associated with cancer and release chemicals that cause inflammation.

What the drug does is it effectively flushes out senescent cells out of the body by disrupting the chemical balance within them. The team led by Dr Peter de Keizer had previously made three fail attempts but were lucky the fourth time around, they report in the journal Cell.

The drug was injected into mice which were genetically modified to age very rapidly as well as in mice that were artificially aged through chemotherapy. Their equivalent age in human years was 90 and the drug was administered three times a week for nearly a year. At the end of the experiments, the rejuvenating effect of the therapy was clear. Age-related loss of fur, poor kidney function, and frailty became reversed.There were no apparent side effects, but that doesn’t mean they’re totally absent. “Mice don’t talk,” Keizer said which is why his team is planning human trials.

The drug itself is a peptide which took nearly four years of trial and error to reach its final form. It works by blocking the ability of a protein implicated in senescence, FOXO4, to tell another protein, p53, not to cause the cell to self-destruct. By interfering with this cross-talk, the senescent cells essentially perform suicide. “Only in senescent cells does this peptide cause cell death,” Kaizer said.

Improvements showed at different times over the course of the treatment. Aged mice that presented patches of missing fur began to grow their coats back after ten days. Fitness levels started to improve after three weeks as tests showed older mice could run twice as far as their counterparts who did not receive the treatment. A month later, the old mice showed improvements in healthy kidney function.

Senescent cells have some beneficial roles in the body. Killing off too many of these cells can trigger cascading complications that can lead to tumour formation. Senescent cells also foster wound healing. With this in mind, a similar treatment meant for humans has to be very well refined else the therapy could end up doing more harm than good. So, it seems very likely that a ‘magic’ age-reversal pill bought over the counter is decades away but it’s exciting to hear about all of these developments now.