Human Nature: Science, Technology, and Life.

The Bio-artificial Industry

How do you feel about mass-producing and selling human tissue in machine form? I hope you like the idea. Because it's on the way.

A few days ago, the University of Michigan trumpeted a study validating the efficacy of its "bioartificial kidneys." In a clinical trial involving people with acute renal injury and failure, the kidney boosters cut the usual death rate (compared to patients using conventional "continuous renal replacement therapy") from two in three patients to one in three.

Pretty amazing. But just what is a "bioartificial" kidney? Here's U-M's description:

The bioartificial kidney includes a cartridge that filters the blood as in traditional kidney dialysis. That cartridge is connected to a renal tubule assist device [RAD], which is made of hollow fibers lined with a type of kidney cell called renal proximal tubule cells. These cells are intended to reclaim vital electrolytes, salt, glucose and water, as well as control production of immune system molecules called cytokines, which the body needs to fight infection. Conventional kidney dialysis machines remove these important components of blood plasma, along with toxic waste products, and cannot provide the immune regulation function of living cells. Initial testing in animals ... found the cells in the RAD perform the metabolic and hormonal functions lost in acute renal failure.

This is the point I've made in recent posts about biological pacemakers and limb regeneration. Prosthetics are nice, but flesh is better. That's why the U.S. Army is now funding tissue regeneration. Instead of trying to reengineer everything in biology, we're learning to borrow, cultivate, and replicate it. Let Mother Nature do the work: She already knows how to filter toxins while keeping what your body needs and regulating your systems.

David Humes, the professor behind the U-M study, is also the scientific founder of the company that's preparing to commercialize the RAD. He envisions the new paradigm this way:

[T]he nature of our new approach -- using living cells as therapeutic agents -- argues for the feasibility of developing whole classes of new cell-based and tissue engineered therapies. The ability to harness vital processes of cells, to target their living molecular machinery on restoring critical substances which have become disordered by disease, has vast implications for the future of medicine. The apparently successful use of living cells in this way validates our approach and should encourage others to investigate cell therapies for a range of disorders.

Technologically, this is a sensible and powerful idea. It will save lives. But as an inflection point in our thinking about human flesh, it's, well, pretty RAD. What we're getting into is not just the commercialization but the mass-production of body parts. It's a bit like PETA's campaign to commercialize lab-grown meat -- except that in this case, the meat will be human.

Where do we get the cells in the cartridge from? According to the American Society of Nephrology, they're "grown from donor kidneys." So we're starting with somebody's donated organ. Instead of transplanting it to one person, we're growing cells from it, which can then be farmed out to multiple patients. We're not just distributing the cells; we're incorporating them into what U-M calls a "living cell cartridge." It's bio -- it's artificial -- it's bio-artificial.

Like lab-grown meat, the living tissue in the cartridge may run into spoilage problems. U-M notes that its researchers are still working on the "challenges of mass producing, storing and shipping a living-cell device." But the goal, according to the nephrology society, is definitely "mass production." And the next step will be to repackage it as a "wearable kidney that performs natural functions unachievable through man-made technology alone." Real flesh, grown from somebody else, mass-produced, packaged into a cartridge, and worn on your body. Good luck sorting the bio from the artificial.

Grow Your Own Pacemaker

By inserting genes into rat heart cells growing in a dish, they were able to create a beating pattern that was faster and more regular than had been seen before. ... [Their first step was] to load up a common cold virus with a pacemaker gene, and then used the virus to successfully infect heart cells in a dish. The infected cells ended up with the gene and began making a pacing current they had lacked. Next the scientists tried the technique in dogs with slow hearts. The gene transfer worked. Parts of the dogs' hearts that had been beating 25 to 40 times per minute were restored to a normal 60 beats per minute. ... [Later] they stitched pacemaker genes into adult stem cells, using a technique that doesn't require viruses, and then injected the altered cells into the heart. ... [W]hen the researchers tested the pacemaker stem cells in dogs for six weeks, the cells behaved just as they hoped. As a precaution, the researchers showed that they could turn off a cellular pacemaker if it becomes hyperactive with a drug ...

This is a great illustration of the point I was trying to make two weeks ago about the superiority of flesh-based technology. First we had flesh but no pacemakers. If your heart lost it rhythm, you had no backup. Now we have electronic pacemakers. They solve the problem of unreliable flesh, but they introduce the problems of electronics. Inserting them requires surgery. Their batteries are finite, and, as we learned from the Medtronic fiasco, their wires can fail. Worse, like other electronic devices, they can be hacked -- in this case, with potentially lethal results.

The long-term solution is flesh. Unlike electronics, flesh can be grown inside your body, avoiding the need for surgery. It's self-correcting, self-repairing, and self-renewing in a way that electronics aren't. And there isn't an easy way to hack somebody else's genes -- at least, not yet. For the same reason, we do need a way to remotely reset your biological pacemaker if it runs out of control. That's where the aforementioned drug comes in. But if you're in the pacemaker market, you had that problem already.

Oransky ends with a wonderful quote from Cohen: "Just like Lasik is a better solution than eyeglasses, a biological pacemaker would be a better solution than an electronic one." Having written about Lasik before, I like the analogy. At the time, I saw Lasik as a potential enhancement of human powers, with athletes boosting their vision beyond 20/20. But as Cohen points out, you can also look at it the other way: Instead of outfitting you with gizmos we've come to think of as normal -- glasses or contacts -- we just fix your flesh. Sometimes the most effective technology is also the most natural.