This is a story about what happens when your heart stops: about new research into how brain cells die and how something as simple as lowering body temperature may keep them alive—research that could ultimately save as many as 100,000 lives a year. And it’s about the mind as well, the visions people report from their deathbeds and the age-old questions about what, if anything, outlives the body. It begins with a challenge to something doctors have always been taught in medical school: that after about five minutes without a pulse, the brain starts dying, followed by heart muscle—the two most voracious consumers of oxygen in the body, victims of their own appetites. The emerging view is that oxygen deprivation is merely the start of a cascade of reactions within and outside the cells that can play out over the succeeding hours, or even days. Dying turns out to be almost as complicated a process as living, and somehow, among its labyrinthine pathways
I find this to be fascinating. Not unlike so many others I have wondered what happens when you die. Where does your mind go? Do you feel any pain? Do you have any understanding of what is happening? Do you go off into the next whatever with the words, sounds and noises of those that were around you?
Becker’s interest in mitochondria reflects a new understanding about how cells die from loss of circulation, or ischemia. Five minutes without oxygen is indeed fatal to brain cells, but the actual dying may take hours, or even days. Doctors have known for a long time that the consequences of ischemia play out over time. “Half the time in cardiac arrest, we get the heart going again, blood pressure is good, everything is going along,” says Dr. Terry Vanden Hoek, director of the Emergency Resuscitation Center at the University of Chicago, “and within a few hours everything crashes and the patient is dead.” It took some time, though, for basic research to supply an explanation. Neumar, working with rats, simulates cardiac arrest and resuscitation, and then examines the neurons at intervals afterward. Up to 24 hours later they appear normal, but then in the next 24 hours, something kicks in and they begin to deteriorate. And Dr. James R. Brorson of the University of Chicago has seen something similar in neural cells grown in culture; deprive them of oxygen and watch for five minutes, or even much longer, and not much happens. “If your car runs out of gas, your engine isn’t destroyed, it just needs fuel,” he says.
Cell death isn’t an event; it’s a process. And in principle, a process can be interrupted. The process appears to begin in the mitochondria, which control the cell’s self-destruct mechanism, known as apoptosis, and a related process, necrosis. Apoptosis is a natural function, destroying cells that are no longer needed or have been damaged in some way. Cancer cells, which might otherwise be killed by apoptosis, survive by shutting down their mitochondria; cancer researchers are looking for ways to turn them back on. Becker is trying to do the opposite, preventing cells that have been injured by lack of oxygen from, in effect, committing suicide.
It’s a daunting problem. “We’re asking the questions,” says one leading researcher, Dr. Norm Abramson of the University of Pittsburgh. “We just haven’t found the answers.” Until recently, the conventional wisdom was that apoptosis couldn’t be stopped once it was underway. It proceeds by a complex sequence of reactions—including inflammation, oxidation and cell-membrane breakdown—none of which seems to respond to traditional therapies. Becker views cell death in cardiac arrest as a two-step process, beginning with oxygen deprivation, which sets up the cell for apoptosis; then the heart starts up again and the patient gets a lungful of oxygen, triggering what is called reperfusion injury. The very substance required to save the patient’s life ends up injuring or killing him.
I truly do not fear death. How can I fear it? I don’t really know anything about it. Don’t misunderstand, I don’t want to die. When I said that I want to live for a thousand years it is because I have so many interests. There is so much to do and so very little time.
To quote my grandfather I’ll fight for every last breath because I can and because I am. It doesn’t have to make sense to you, but it does to me.
My children are a huge part of my interest in living. It is not just because I can’t imagine not being there for them but because I am intensely curious about who they are going to become. When they grow up who will they be. What will they do and with whom?
Anyway, I think that the article is quite interesting. Give it a read.
Hi Stephen,
It is my pleasure. Since I read it yesterday evening my head has been filled with all sorts of interesting thoughts.
A fascinating article. Thanks for sharing, Jack.