Brain death is normally seen as crossing the last frontier of life, at least in a clinical setting. Until a patient has gone through brain death, we believe that some vestige of their personality must still be in there. But injury to the CNS, especially axonal trauma, is usually irreversible. Once the brain is dead, there are no palatable options. Trying to handle situations like this can be a lot like trying to handle dry ice with bare hands. So, in a proof-of-concept experiment that’s equal parts touchingly earnest and slightly creepy, a couple of biotech companies called Bioquark and Revita just got approval for a Phase 1 clinical trial aimed at reversing brain death.
The experiments aren’t likely to succeed. But the ways they fail will be illuminating. The researchers are really planning on a blitzkrieg approach. In the Phase 1 trial statement, they explain that they will use some permutation of stem cells, peptide extracts, lasers and nerve stimulators. (No relation to Dr. Crusher’s cortical stimulator.) The stem cells aren’t just neuronal progenitor stem cells, though; they’re using stem cells from the mesenchyme, the embryonic germ layer that gives rise to both neurons and their support cells, glia.
If the researchers can convince the stem cells to differentiate properly, they might actually achieve the growth of real brain tissue, not just neurons. They don’t specifically talk about their intentions in their Phase 1 writeup or their own press release — it isn’t clear whether they’re going to try to convince still-viable brain tissue to repair or regrow axons by applying lasers and peptides, or to implant stem cells in such tissue, or to start with stem cells in vitro and grow a matrix and then implant that. In any case, such an achievement would be pivotal, not least because we’ve never yet managed to do it.
Subjects accepted into this study will be traumatic brain injury (TBI) victims, who have suffered diffuse axonal damage. The long, slender nerve bodies have been sheared or crushed, and now they can’t repair the damage. Normally this is fatal, and the researchers are careful to point out that they don’t expect to be able to reanimate dead people. They note, in an understatement of positively British proportion, that you might not get the same person back after such an attempt. No, the goal here is much more conservative, but more desirable for it. If these experiments succeed, it will be an important proof of concept. If stem cell isografts can integrate themselves into the brain, they could cleanly heal what would have been a devastating or even lethal brain injury. Death is supposed to be irreversible, but we might get a chance to stay the hand of the Grim Reaper, if only in just a few cases.
That prospect, of course, is what makes these experiments worth doing. Despite the superficial squick factor, the emergent technologies at play here have the power to change the entire landscape of neuroscience, and with it our understanding of the human brain’s regenerative capabilities. We could produce actual human brain tissue to experiment on, without ever having to take a brain biopsy. We could convince brains to patch themselves, giving the CNS the power to heal like a lizard.
The above is why this whole series of experiments begs for jokes about the zombie apocalypse. In the same universe that produced Resident Evil and 28 Days Later, wouldn’t this inevitably result in fast zombies with great regenerative abilities? What happens when splattering their brains doesn’t actually destroy them?