Looking youthful has been seen as a desirable trait for humans for centuries. Ageing is an inevitable process, and although many people may hope to keep the body they have during their 20s and free (relatively speaking at least) from pains and wrinkles for the rest of their life, this is not possible as we know it. Or is it? New studies are often popping up, some of which claim that reversing ageing is not possible, while others claim that exciting discoveries have been made that suggest it might be.

To start with, what is ‘ageing’? Obviously, in terms of our body’s age, ageing refers to getting ‘older’, represented by the number of years we’ve been alive. But ageing also has importance on a cellular level. After all, something must be going on to allow us to grow when we’re younger, experience social and physical changes during young adulthood and then develop the changes in our bodies that we classically associate with ageing, such as developing wrinkles, getting joint pains and becoming more forgetful.

Though there are many theories regarding ageing floating around, it’s best to focus on what we can accrue evidence for. For example, we can visualise the effects of ageing on cells. Most of our cells divides constantly, allowing fresh new cells to support us. However, every time a division occurs, some DNA at the end of each chromosome is lost. As you can imagine, this can have serious implications for the integrity of our genome, so we have protective “caps” at the end of chromosomes called telomeres. These telomeres function as a buffer, and so every time a cell division occurs, telomeric DNA – not DNA from our genes – is lost. However, there is a limit to how much telomeric DNA we can lose, and once we lose too much, the cell automatically goes either into a hibernation-like state or through programmed cell death. This essentially acts as a limit to the number of divisions a cell can go through.

“Several experimental studies also claim to have evidence that ageing can be reversed”

Cells also become less efficient at carrying out their functions and experience a build-up of waste substances and fats. In younger cells, when the parts of the cell (called organelles) become damaged, they are effectively degraded to protect the cell. In older cells, this clearance is affected, leading to the build-up of toxic substances that can lead to protein damage, contributing to poorer cell function.

With an understanding of these molecular processes, scientists have been able to develop experiments aimed at influencing processes known to contribute to ageing. The findings from studies on whether or not the effects of ageing is reversible have often clashed. An international scientific collaboration across 14 countries, which gained much attention in the press, claimed that their evidence supported the “invariant rate of ageing” hypothesis, which states that individuals have a fixed rate of ageing. Many other studies also similarly claim that ageing is an irreversible process.

On the flip side, several experimental studies also claim to have evidence proving ageing can be reversed. A study showed it was possible to not only reverse the ageing of human cells in a lab, but even extend the life of a live mouse with an accelerated-ageing condition. A recently published study details research conducted at the Babraham Institute in Cambridge. The team behind the study used a technique called somatic cell reprogramming that leads to the formation of a type of cell called induced pluripotent stem cells (iPSCs), which are multifunctional stem cells that can be generated from adult cells. This process is an adaptation of the technique used to clone the first animal from an adult cell, Dolly the sheep.

“This led to skin cells from a 53 year-old woman looking and behaving like they were from a 23 year-old”

Data from both this study and other studies have shown that when using the somatic cell reprogramming technique, cells do not need to be completely converted to iPSCs to show signs of rejuvenation. The study involved a novel method called “maturation phase transient reprogramming”, where the researchers carefully controlled how they were using the reprogramming factors needed to make iPSCs. As soon as the cells reached a rejuvenation point, the factors were withdrawn, before the cells completely changed into stem cells. This led to skin cells from a 53-year-old woman looking and behaving like they were from a 23-year-old.

This study is more of a proof of concept rather than a definitive discovery; it supports the theory that cells can indeed be rejuvenated. The process needs to be tweaked, or a new method found, to offer an appropriate balance between feasibility and safety, but at least we’re getting somewhere. This study could have significant implications for disease, helping to reverse ageing-related factors behind different ailments, and may even be applicable in cosmetics. There will be many ethical issues that need to be considered first to ensure that the rejuvenation of cells is done in a controlled manner if it is ever made available as a treatment. Nevertheless, these are exciting times, and we may be approaching the age of anti-ageing.