3 min readHere’s what you’ll learn when you read this story:
- Your skin has an inner structure called rete ridges, which act as a kind of Velcro, holding the layers together. It’s involved in enabling new cell growth and organizes your skin tissues.
- Scientists are exploring pig skin to gain a fuller understanding of how this process works.
- The result could mean uncovering the ability to truly regenerate your skin after damage, or even enable the maintenance of youthful skin.
One of the biggest appeals of superheroes is imagining yourself with otherworldly powers. While most superhuman abilities remain strictly science fiction, some are appearing more and more possible.
Take, for instance, Wolverine. While most think of giant adamantium claws, impressive mutton chops, or Hugh Jackman (or possibly all three), Wolverine’s remarkable ability to regenerate from grievous injury is his true superpower. Any time his mutant powers kick in, his skin miraculously stitches together, leaving him no worse for wear.
By far the most accessible organ of the human body, skin offers a fascinating template for exploring how we non-mutants could one day boast impressive, Wolverine-like regenerative powers. But to unlock those secrets, scientists need to first build an accurate understanding of how our skin works. Eventually, the knowledge could lead to advanced healing techniques for conditions like psoriasis and burns, and even lab models that reveal how to keep skin younger for longer.
That means exploring rete ridges, a kind of “biological Velcro” that holds together the outer layer of the skin, or epidermis, to the underlying dermis. Your sweat glands and hair follicles combined can’t outnumber your skin’s rete ridges, says Washington State University’s Ryan Driskell, a senior author of a new paper in the journal Nature exploring the role of these structures in maintaining youthful skin. “You can’t be like Wolverine unless you can regenerate your rete ridges,” he says.
However, getting healthy, normal samples of rete ridges has been an ethically questionable and controversial pursuit. Initially, scientists believed that rete ridges form sometime during the development of an embryo, just like hair follicles and sweat glands. This new paper explains that rete ridges actually form postnatally. Yet, if you picture asking a new parent if they wouldn’t mind donating some newborn skin for science—you can likely anticipate the answer.
So, Driskell and his team were on a mission to find some other animal with rete ridges similar to human ones. Despite their ubiquity in human skin, the presence of these ridges in mammals is much more varied. In fact, our closest genetic neighbors, chimpanzees, have very few rete ridges, and the same is true of mice, the stand-in mammal model for scientific research. Luckily, a close human equivalent was found in pigs.
While it may seem strange that porcine skin is more like our own than other primates’ skin, it makes more sense when you know there is an inverse relationship between the number of hair follicles and rete ridges. Less hair, such as humans and pigs, means more of these Velcro-like structures. Driskell’s lab in rural eastern Washington is fortunate, having ready access to pig skin thanks to local byproducts of nearby animal agriculture.
“We know more about what goes wrong in human skin than we know about what’s normal,” Driskell says. “By focusing on pigs, we can ask, ‘what is human skin really and how should we be looking at it?’”
Already, using pigs as a model for rete ridges is paying dividends. Using advanced genetic mapping techniques, the team identified a key “biological pathway,” or set of molecular instructions, which builds the rete ridges. This bone morphogenetic protein (BMP) guides how cells communicate and organize into complex tissue.
But BMP tapers off as we age. Potentially reactivating these pathways temporarily could be the key to restoring youthful skin and healing scar tissue, including after severe burns. This will also help scientists develop more accurate organoids, lab-grown mini-models that mimic human skin and make more advanced research possible.
“BMP is finding one specific type of nail you need to build a house,” Driskell says. “There are a lot of different kinds of nails you need to make a house…right now what we’re able to show is that we’ve created the blueprints and now we can start to figure out the different nails and hammers…that’s where the future lies.”
So while the Wolverine dream remains tantalizingly out of reach, scientists like Driskell are laying the molecular foundation for a future where skin regeneration—whether cosmetic or medical—isn’t confined to the comic panel.
Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.