Cellular Regeneration

Although often glossed over, the human liver is a pretty amazing organ. Not just because it’s pretty much the sole thing that prevents our food from killing us, but also because it’s the only organ in our body that is capable of significant regeneration. This is a major boon in medicine, as you can remove most of a person’s liver and it’ll happily regrow back to its original volume. Obviously this is very convenient in the case of disease or when performing a liver transplant.

Despite tissue regeneration being very common among animals, most mammalian species have only limited regenerative ability. This means that while some species can easily regrow entire limbs and organs including eyes as well as parts of their brain, us humans and our primate cousins are lucky if we can even count on our liver to do that thing, while limbs and eyes are lost forever.

This raises many questions, including whether the deactivation of regenerative capabilities is just an evolutionary glitch, and how easily we might be able to turn it back on.

Continue reading “Be More Axolotl: How Humans May One Day Regrow Limbs And Organs” →

Although we often regard our own bodies and those of the other multicellular organisms around us as a singular entity, each cell that makes up our body is its own, nano-robot. One long-existing question was whether these cells can be used for other tasks — like biological robots — after they have specialized into a specific tissue type, with a recent study by [Gizem Gumuskaya] and colleagues in Advanced Science (with Nature news coverage) indicating a potential intriguing use of adult human epithelial cells recovered from the trachea.

Human bronchial epithelial cells self-construct into multicellular motile living architectures. (Credit: Gumuskaya et al., 2023)

After extraction, these adult cells were kept in an extracellular matrix (ECM, Matrigel) in conditions promoting cell division, followed by ECM dissolution after 14 days and subsequent culturing of the spherical clumps of cells that had thus formed in a water-based, low-viscosity environment. This environment, along with the addition of retinoic acid promoted the development of outward-facing cilia, rather than the typical inward type with a gel-based ECM.

These spheroids (anthrobots, referencing their human origin) generally showed the ability to move using these cilia, with the direction largely determined by the symmetry of the sphere. Multiple of these motile spheroids were then placed on a layer of human neural tissue, in which a scratch had damaged a number of the neurons to form a gap. The anthrobots grouped together over the course of days to form a bridge across the gap, with the neural tissue observed to regrow underneath this bridge, a behavior that could not be repeated by using a dummy support consisting out of agarose on another neural sample, indicating that it is this living bridge that enabled neural regeneration.

Although the researchers rightfully indicate that they are uncertain which factors actually induce this restorative effect in the neurons, it offers exciting glimpses into a potential feature where neural damage is easily repaired, and biological robots made from our own cells can be assembled to perform a variety of tasks.