Killing senescent cells with the FOXO4 peptide
In short: senescent cells accumulate in the body, causing diseases associated with age. To kill specifically those cells and no other, you can use FOXO4-DRI, a peptide designed to stop the FOXO4 gene from interacting with the p53 gene. There are no "official" human trials at the moment, although at least two people are testing on themselves. Cost for the peptide is currently $1756.80 for a day's dosage. This will go down over time.
When a cell becomes damaged or its telomeres shorten too far, it turns “senescent”. This means that it no longer divides, so new cells cannot be created from it.
Senescent cells remain active, though, secreting factors that contribute to inflammation, type 2 diabetes, atherosclerosis and other age-related diseases.
The longer you live, the more senescent cells you have, the more likely you will develop these diseases.
In March 2017, a paper was published showing that it is possible to target senescent cells and destroy them using a FOXO4 peptide. Molecules that specifically kill senescent cells are called senolytics. Others include Quercetin and Navitoclax.
In senescent cells, the FOX04 gene interacts with the p53 gene to prevent the cell from dying, but a peptide (short amino string) has been designed which can block the interaction by connecting to the FOXO4 so that it is unable to connect to the p53. This allows the cell to then proceed to apoptosis.
FOXO4 is hardly ever expressed in non-senescent cells, so interfering with it does not kill off the young cells that you want to keep.
The team that developed the treatment, led by Peter de Keizer of the Erasmus University Medical Center in The Netherlands, tested it for ten months on mice, and no side-effects were found at all.
The mice that were tested were fast-aging mice.
the mouse on the left was treated with the FOXO4 peptide
Treated mice that had missing fur started regrowing their fur back after ten days.
After three weeks, it was obvious that the treated mice were more fit, running twice the distance their non-treated friends could run.
A month after treatment, there were markers of increased health in kidney function.
Human safety studies are still in planning, it is yet to be shown that this treatment increases the lifespan of the mice, and even if you do want to buy the stuff, it's incredibly expensive for even the smallest amount, but this is still very exciting.