The question of death has puzzled humans probably for as long as humanity has been around. We ask big, sweeping questions such as, “What happens to us after we die?” and even “Why does death exist?” These are philosophical and religious questions—things science cannot answer, and whose answers we might not accept even if it could. But there are other, more mundane questions that are just as perplexing.
For instance, “What does it mean to be ‘dead’?” and even more importantly, “How do we decide when someone actually is dead and not just in a coma or something? What constitutes ‘dead’?” They’re surprisingly difficult questions to answer, and we’ve wrestled with them throughout the ages and continue to do so even today.
Well, these questions just got even stickier than they were. Because science has discovered something truly incredible: hundreds of genes keep working even after we’re dead—dead in every possible sense of the word. As inconceivable as it seems, these genes may continue to function for as long as two whole days after death. And even more astonishing is this: some of them don’t turn on until after we die.
Warning: not for the squeamish
The way we define “death” has changed over the years—and I’m not just talking about differences between, say, the Middle Ages and the present. Just in the past 30 years our understanding of and definition of what constitutes “dead” has changed rather dramatically—so much so that in 1980 a law was passed defining “death.” It’s called the Uniform Determination of Death Act and its goal was to offer states "comprehensive bases for determining death in all situations." This Act says that:
"An individual who has sustained either (1) irreversible cessation of circulatory and respiratory functions, or (2) irreversible cessation of all functions of the entire brain, including the brain stem, is dead.”
So while most of us probably think of death as the permanent end of all bodily functions, legally we have two kinds of death. That is, “circulatory-respiratory” death, in which the heart and breathing have permanently stopped; and so-called brain death.
In other words, we’re not so far as we’d like to think from the cavemen, poking our fallen comrades with sticks and thinking, “Ug not moving. Wake up, Ug!” The truth is that as with so many things in science and medicine, we just don’t understand as much as we’d like to pretend we do.
But whatever the legal definitions, there comes a point where there’s no question that real and final death has occurred. Rigor mortis sets in. Tissues start to degrade. Gasses build up. Decomposition begins. And it’s after this point of no return—not after one of the mere legal definitions of “dead”—that the shocking evidence of living genes at work has been documented.
No, I’m not suggesting that zombies are real, and neither are the researchers who produced this study. But it does appear that the body, even after the cessation of all bodily processes, makes one last-ditch effort to stay alive. And that could give science some insight into problems it has wrestled with for years.
Even in death, the body is trying to revive itself
Before I go any further, I’d like to add the disclaimer that this research was done on mice and zebrafish. However, mice are commonly used as stand-ins for humans in scientific research. Many a drug has started out being tested on mice, and many non-drug treatment too. No one has formally looked into this phenomenon in dead human beings. But—other researchers have noticed the same kind of thing happening with some human genes. There just hasn’t been any formal study done.
In other words: mice aren’t people, but it’s almost a given that the same thing happens to us too. But just exactly what is happening? Here’s what we know.
The study came from researchers at the University of Washington, Seattle. They looked at the activity level of genes in the brains and livers of mice and zebrafish immediately after death. They tested samples at regular intervals over the space of four days.
They found that more than 500 genes had an increase in activity after the animal died. This in itself is beyond shocking. Death is...well…final. You’d expect genes to switch off along with everything else once death occurs. And this is what did indeed happen with many genes. But some remained active, while others which had been inactive suddenly “switched on.” And looking at which genes are involved suggests that it’s a final desperate attempt by the body to heal itself or restart functions.
Many of the active genes were those that regulate healing processes such as inflammation. Others were genes which have been associated with cancer—rampant cell production. And perhaps most interestingly, some of the genes that “woke up” were fetal development genes which shut down immediately after birth.
This suggests that the body is frantically attempting to “reboot” itself—to heal from whatever trauma or disease ended the life that powered it.
How far will science take this knowledge?
The observations in human bodies bear this out so far. Other studies have found that human genes involved in healing wounds and making the heart contract were active for more than twelve hours after death. The bodies studied had died from multiple traumas, heart attacks, or suffocation.
Our bodies want to live. And they’ll keep trying to revive us long after it’s a lost cause.
Or is it?
The authors of the University of Washington studies pose the question:
"What would happen if we arrested the process of dying by providing nutrients and oxygen to tissues? It might be possible for cells to revert back to life or take some interesting path to differentiating into something new..."
I shudder to think what kind of pathways this kind of experiment could lead us down in the future. But at the moment, there is one good thing that might come of this study. We’ve long known that organ transplant recipients are much more likely to develop cancer in the transplanted organ than the general population is.
The speculation is that gene activity after tissue death could both “turn on” cancer genes and shut down genes that normally keep cancer in check. Cancer is, after all, unchecked cellular reproduction. The genes that come to life after death in an effort to revive the body could stay activated and contribute to later cancers. The information gleaned from studying post-mortem gene activity could help scientists discover how to mitigate that risk.
This research is both amazing and unsettling. It challenges what we’ve always believed to be true. And we can only hope that, as the issue gets more study, scientists are motivated to stay within ethical boundaries. There was only one Lazarus, and he wasn’t resurrected by a scientist in a lab. Is science really arrogant enough to attempt to go there? Only time will tell.