I’m sure many of you read the news – scientists somehow made pig brains come back to life a few hours after the pigs died. Of course, most news sites had to produced clickbait headlines, and since most people don’t read beyond those headlines, there is a whole new mythos about these zombie pig brains.
We’re here to correct some of that information. Hopefully, a few people will look beyond the headline to examine the science rather than fall for pseudoscientific dreck.
The pig brains study
In a paper published in Nature, scientists described taking 32 pig brains from a slaughterhouse and waited four hours post-mortem. Then, they hooked up the brains for six hours to a system called “BrainEx,” which provided the brains with oxygen, nutrients, and protective chemicals.
BrainEx is a very complicated system, not something that your basic evil scientist can use to create an army of zombies.
The perfusate that bathed the brain contained chemicals that stopped oxidation of cells and apoptosis (cell bursting after death). It also contained a neural activity blocker that halted excitotoxicity and to prevent the brain from regaining any level of consciousness. In fact, if consciousness was detected by an EEG, the researchers would shut down the experiment. In fact, they stood by with anesthesia in case the EEG showed neural activity.
After about 10 hours, the scientists determined that the tissue of the pig brains were largely intact, compared to control brains that were not treated. The brain cells were performing their usual metabolic process such as consuming oxygen and nutrients while producing carbon dioxide.
So, it was not a functioning brain. It could not think, it could not comprehend its environment, and it could not manage any biological process. It was merely cells that were functioning, not a whole living brain. It was no different than taking liver cells from a human, growing them in cell culture, and claiming it’s a functioning liver – it isn’t.
Therefore, just so it’s absolutely clear, these pig brains lacked consciousness. The individual brain cells were incapable of communicating with one another, so they were just brain cells. That’s it.
The value of this study is that it showed it was possible to get these brain cells to work even a few hours after death. Until now, it was thought that brain cells broke down and had no function after a few minutes.
I also want to point out another important issue. This experiment has just been published, and it has not been repeated by other researchers. The results are provisional, and it will be years before we know if this preliminary study has any meaning going forward.
Ethical considerations of zombie pig brains
I know that the first thing on everyone’s mind would be how soon can we treat those with traumatic brain injuries, stroke, or even death. Well, stop, take a deep breath, and let’s consider some of the ethics.
- As I mentioned above, the study did not produce a functioning pig brain. The study’s design prevented that from happening. The overwhelming concern is, and will continue to be, whether it would be ethical to actually create reanimated pig brain that would suddenly re-experience the horrible end of its life. I do not if we could ever overcome this particular ethical issue, but if this study is to ever proceed beyond just making cells function again,
- If scientists and ethicists have concerns about a pig study, we couldn’t even begin to consider one for humans. I could not imagine a study where we take a human head, a few hours after death, to see if the BrainEx system worked on it. And if it did, then what? The experience of the horror of suddenly coming back to life could be overwhelming, especially if all other parts of the body were not functioning. This would make a good horror movie, but it would not make for good medicine.
- And even if we thought this system would work for humans, how do we create a valid scientific study to show that it did? How do we create controls? How do we choose patients? I can’t see any clear path to this type of study.
- How do we prevent the pseudoscience quacks and charlatans from using this method from selling it to the highest bidder to treat a family member in a vegetative state?
These are all difficult questions to answer since they move beyond scientific considerations to ethical ones.
But one more thing that sometimes people forget – research like this rarely, I mean far less than 10% of the time, ends up having any clinical importance to anything. Whenever I see a preclinical study, my comments are usually along these lines – this is in mice (or pigs), so call me when it’s in clinical trials. And I remain unconvinced that this type of study will ever get to clinical trials.
What is the importance of this research?
I don’t think this research is as groundbreaking as the popular press has made us believe. I think it has given us limited information about neurological cell death, not as a way to revive human beings from death or brain damage. This isn’t going to lead to a zombie army some day.
However, if we can satisfy the ethical quandaries, we might be able to develop a method to repair brains and nerves after being damaged or deprived of oxygen as a result of a brain injury. I’m not saying bring back a dead person – we’ll leave that to science fiction, not science. Maybe this is the first step to quickly treating someone after a stroke, for example.
But still, I’m not convinced we have the ability to do even that much given how difficult it might be to even do a clinical trial in a large enough group to get statistically useful results.
- Vrselja Z, Daniele SG, Silbereis J, Talpo F, Morozov YM, Sousa AMM, Tanaka BS, Skarica M, Pletikos M, Kaur N, Zhuang ZW, Liu Z, Alkawadri R, Sinusas AJ, Latham SR, Waxman SG, Sestan N. Restoration of brain circulation and cellular functions hours post-mortem. Nature. 2019 Apr;568(7752):336-343. doi: 10.1038/s41586-019-1099-1. Epub 2019 Apr 17. PubMed PMID: 30996318.