DNA helix, a cartoon by Jerome Walker, via Wikimedia Commons
Our civilisation is obsessed with youth and beauty. Face is sometimes called the mirror of our soul and we all want to keep this mirror clean, smooth and shiny. And this is what beauty industries are focused on. Of course, there’s a great competition among beauticians and we often hear about secret formulas and ingredients working as elixirs of youth.
Yet, can we trust all those fabulous ads talking about cutting-edge science products? Some studies argue that common moisturisers with sunscreens are as effective as elaborate and expensive skin creams. However, beauty companies claim that some of their new compounds do have a beneficial effect on skin health.
Can we prolong the youth of our skin without expensive spa-solicited skin care? Are expensive skin creams really worth their price or we’re tricked to believe they are?
Anti-ageing creams have evolved dramatically over the past century thanks to enormous advances made in natural sciences. Good old lipid-based (Vaseline) creams aren’t good enough anymore. Herbal extracts are helpful but clearly not potent enough to stop aging. Polysaccharides like hyaluronic acid and fibrous proteins like collagen were a breakthrough in the 90s, but now we live in the new millennium and we still age. What else we can come up with? Let’s get at the heart of the problem.
Science tells us that our body is programmed to age. Our cells can divide only a limited amount of times, and then they senesce and die. This limit of cell divisions is caused by gradual shortening of the ends of chromosomes called telomeres occurring with every cell division. Telomeres can be sustained in some cell types like stem cells and germ-line (cells which differentiate into gametes – sperm and eggs) and that’s how we can pass our DNA virtually unharmed to our children. In somatic cells like skin cells the eventual loss of telomeres is inevitable and results in disruption of chromosome integrity and subsequent cell death.
Another reason for ageing is chemical damage (like oxidation), which leads to destruction of cellular and extracellular matrix bio-macromolecules. UV and reactive oxygen radicals can permeate the dead cell layer of epidermis and damage DNA of live skin cells, which accelerates ageing. Another result of such damage may be cancer, for mutations caused by UV and oxidation may turn healthy skin cells into cancerous. The example is melanoma.
That’s why DNA is the current trend in the beauty industry. Many new products boast to be able to repair damaged DNA of skin cells. Common sunscreens containing zinc oxide would only deflect and absorb the UV radiation, but a small amount of UV and oxygen radicals can still target and damage our cells.
The anatomy of skin
New generations of skin creams contain DNA repair enzymes, which can avert the sun damage. One such protein is DNA photolyase derived from a cyanobacterium. You may wonder whether it’s wise to administer a foreign protein into our skin, especially of bacterial origin, which may cause an immune reaction in our body akin to skin allergy. I guess the allergy tests should address this issue.
A second issue is the protein delivery to skin cells. Many scientists dismiss all these revolutionary skin creams as fraud, because they assume that skin is a barrier and proteins are too big to get through. Indeed, the outer several layers of epidermis are dying or dead keratinocytes, – there’s nothing to repair there. How would the skin cream components reach the live cells beneath?
Apparently, there is space between cells called extracellular matrix, which allows for such penetration. I give you an overview of an example study below, which shows that proteins CAN spread inside our skin, especially if suitable delivery methods, liposomes or nano-dispersion spray, are used.
Tahara and colleagues used fluorescently-labelled insulin, GFP and other proteins to monitor their traffic across the skin pieces in vitro. As you can see on the figure below insulin (labelled green) could gradually spread across 1mm-thick skin in 48 hours. Most of the protein accumulated within 15 μM area of the skin section, and the authors observed the bigger proteins like GFP get through to a more limited extent.
Fluorescence microscopy of the YMP skin sections treated with the samples containing FITC-labeled insulin visualized through a 10× objective (scale bar: 200 μm). Samples to which a S/O nanodispersion (A–E) was applied at 0, 12, 24, 36, 48 h, and a control (F) (aqueous solution) was applied at 48 h. At the left side of the sections, the skin surface is displayed. (Tahara et al., 2008; Journal of Controlled Release, 131(1): 14-18)
Studies like this confirm that enzyme-boosted skin creams can indeed reach the addressee (live skin cells), but whether these proteins are very effective and can indeed prevent sun-induced DNA damage or not is still a controversial matter, though some promising data supporting the claim have been published.
Other creams are created to repair DNA telomeres (tips of chromosomes). So far I’m sceptical about that. The active compound in this case is teprenone (marketed as Renovage) has been used as a medicine for stomach ulcers, but there’re no published studies so far exploring its effect on telomeres. An independent investigation came to conclusion that Renovage’s DNA repair quality is a myth (my kind word).
In fact, the only way telomeres are known to be extended is via telomerase, an enzymatic protein synthesising DNA extensions called telomere repeats. It’s possible that certain compounds, may be even teprenone, can induce or enhance production of telomerase inside somatic cells, including epidermis. But this would be dangerous for our body, as unlimited division of somatic cells may favour their transformation into constantly dividing cancer cells. Telomerase production is under a tight control in our cells and I wouldn’t mess with this safeguard if I was a beautician. Especially considering that we still don’t know much about the biology of cellular ageing.
So, if you don’t have spare money, just use regular sunscreen and moisturisers.
“Immortal Beauty” by Thomas McDermott
I hope I gave you here some food for thought and now it’s time for entertainment. If you like adventure and thriller stories spiced with fantasy and history, then you should definitely read Thomas McDermott’s novel called Immortal Beauty, which is available on Amazon Kindle. The central character Celine D’Áumont, a head of a Paris-based cosmetic company, is about to announce a new product, which prevents ageing. But can you trust this gorgeous business lady who has been holding a grudge against our civilisation for centuries? Go and find out.