Friday, August 29, 2014

Regeneration: Getting Closer to Growing Lost Organs

Too many folks die, waiting for a compatible donor organ. We can't coax a patient's body into growing a new heart or kidney: yet.

But we can build made-to-order bladders, and scientists have grown a new thymus: inside a mouse. It's a first step.
  1. Growing a Thymus from Scratch
  2. First Steps: Growing Liver Buds
  3. Replacement Parts, Grown to Order: Bladders Today; Hands — Eventually, Maybe
This post has a sort of epilogue about what changes, what doesn't, and why I like living in 'the future.'

Starfish Do It - - -

(From Natural History Museum in London, via Wikimedia Commons, used w/o permission.)
(" 'Comet' of Linckia guildingi, showing starfish body regrowing from a single arm"

Some starfish eat clams. So do humans. Folks whose livelihood depended on the clam harvest sometimes got frustrated when starfish got at the clams before they did: and killed the echinoderms by cutting them to pieces. and tossing the pieces back into the ocean.

I don't think they were being vindictive. Starfish earned a reputation for being tough critters.

We don't do that as much these days: partly because folks noticed that starfish grow new limbs: and sometimes severed limbs grow new starfish.

- - - Skinks Do It - - -

Some geckos, skinks, lizards, salamanders and tuatara, can 'shed' a tail or limb: escaping while a predator catches the severed part. Scientists call this startling ability autotomy. At least two species of African spiny mice have breakaway skin. (Apathetic Lemming of the North (June 13, 2013)

Those amphibians and reptiles regrow their limbs. Remarkably, the mice grow new skin: complete with hair follicles, sweat glands, and little to no scarring.

Humans occasionally regrow lost fingertips and toes, and can sometimes regrow injured parts of our liver. But the new toes and fingers look odd, without fingerprints and with squarish nails: or no nails at all.


- - - Why Can't We?

If starfish and some mice can regenerate complete missing parts: why can't we?

Right now, we don't know. Not for sure. It probably has something to do with our immune system, and the way our bodies deal with injury.

At least some amphibians have a lot fewer lymphocytes (white blood cells) while they're regrowing missing parts, and don't grow connective tissue over wounds the way we do.

The good news is that we've got really effective immune systems. Even plagues like the Black Death didn't manage to kill off more than about half the population in Europe.

We still have influenza epidemics, and there's an ongoing Ebola outbreak in West Africa: but we've learned a lot since the 1300s, and are learning more. (June 13, 2014; February 12, 2014; January 13, 2013)

Regenerating severed limbs is still a long way off, but like I said: we're learning.

1. Growing a Thymus from Scratch

(From SPL/Science Photo Library, via BBC News; used w/o permission.)
("The thymus produces T-cells, a part of the immune system"
(BBC News))
"Whole organ 'grown' in world first"
James Gallagher, BBC News (August 24, 2014)

"A whole functional organ has been grown from scratch inside an animal for the first time, say researchers in Scotland.

"A group of cells developed into a thymus - a critical part of the immune system - when transplanted into mice.

"The findings, published in Nature Cell Biology, could pave the way to alternatives to organ transplantation.

"Experts said the research was promising, but still years away from human therapies.

"The thymus is found near the heart and produces a component of the immune system, called T-cells, which fight infection...."
Until we're able to regenerate lost or damaged organs, some of us will need transplants.

That's why I'm excited about this research. It looks like someone needing a new organ may be able to grow one. We're already able to grow replacements for the body's simpler parts:
"...There are already patients with lab-grown blood vessels, windpipes and bladders. These have been made by 'seeding' a patient's cells into a scaffold which is then implanted."
(James Gallagher, BBC News)
The technique used to grow the mouse thymus involves cells from embryos. Doing the same for humans presents problems: some technical, one ethical.

Technical Issues

Since its DNA is from another critter, the little mousy thymus isn't compatible with the host mouse. On top of that, researchers aren't quite certain that the new thymus will stop growing when it should.

For humans, a replacement thymus grown with this technique would be subject to transpalant rejection. Our immune systems are pretty good at killing off anything inside us that's not on the body's 'approved' list: including many transplanted organs.

That's why doctors are so fussy about getting a good match for transplants, and why my replacement parts are biologically inert.


The big problem with this technique is where researchers would get cells for the new thymus. Killing a very young human to help an older one is not right. We can't " evil that good may come of it...." (Romans 3:8)

Actually, we can. We've got free will. But we shouldn't.

Since I'm a Catholic, I have no problem with organ transplants: provided that someone isn't disabled or killed in the process. Health is a "precious gift." We're expected to take care of our health: within reason. (Catechism of the Catholic Church, 2288-2296)

Bottom line, doing something bad so that something good will happen isn't right. (Catechism, 1756)

I'm not upset that one mouse had to be killed to give another mouse a new thymus. I like animals, recognize that humans are animals, but know that we're not just animals; and that's another topic. Topics. (July 27, 2012; August 31, 2011)

2. First Steps: Growing Liver Buds

"Tiny stem-cell livers grown in laboratory"
James Gallagher, BBC News (July 3, 2013)

"Tiny functioning human livers have been grown from stem cells in the laboratory by scientists in Japan.

"They said they were 'gobsmacked' when liver buds, the earliest stage of the organ's development, formed spontaneously.

"The team, reporting their findings in Nature, hope that transplanting thousands of liver buds could reverse liver failure.

"Experts welcomed the findings, describing them as 'exciting'.

"Scientists around the world are trying to grow organs in the lab to overcome a shortage of organ donors.

"Some patients already have bladders made from their own cells, but dense solid organs such as the liver and kidneys are much harder to produce...."
The little liver buds hooked themselves into the circulatory system of the host mice and started acting like miniature livers. This is good news for folks who might need a new liver: decades from now.

There's a lot more research to be done before this is ready for humans, though. Again, one of the problems is that the scientists aren't sure that the liver buds would stop growing when they're supposed to.

There may be other technical issues, including the possibility that medications used in this procedure are toxic for humans. We've got quite a bit in common with mice: but we're not mice.

I trust that the human stem cells they used came from someone who survived the extraction.

We're expected to learn more about how things work. Using science and developing new technology are part of being human. Ethics apply, of course, just like anything else we do. (Catechism, 2292-2295)

Using stem cells isn't wrong. Killing someone to get their stem cells, kidneys, or anything else: that's what's wrong.

3. Replacement Parts, Grown to Order: Bladders Today; Hands — Eventually, Maybe

(From BBC News, used w/o permission.)
((left) "Is the idea of growing hands a myth or a far-off reality?" (right) "A bladder scaffold is used to hold together the new structure"
(BBC News))
"Will we ever grow replacement hands?"
James Gallagher, BBC News (March 20, 2012)

"It might seem unbelievable, but researchers can grow organs in the laboratory. There are patients walking around with body parts which have been designed and built by doctors out of a patient's own cells.

"Over the past few weeks on the BBC News website we have looked at the potential for bionic body parts and artificial organs to repair the human body. Now we take a look at 'growing-your-own'.

"There is a pressing need. A shortage of available organs means many die on waiting lists and those that get an organ must spend a lifetime on immunosuppressant drugs to avoid rejection.

"The idea is that using a patient's own stem cells to grow new body parts avoids the whole issue of rejection as well as waiting for a donor.

"Dr Anthony Atala, director of the Institute for Regenerative Medicine at the Wake Forest Baptist Medical Center in North Carolina, US, has made breakthroughs in building bladders and urethras...."
Besides sidestepping dangers of tissue rejection, "using a patient's own stem cells" means that the donor is also the patient: avoiding some ethical complications.

I'm an adult, in moderately good health — diabetes and a few neurological glitches aside — so I've got stem cells in my bone marrow, intestines, and a few other places. I can afford to lose a fraction of that supply: just as I get along fine after medicos take another blood sample.

I suppose someone might have religious objections to now-routine medical procedures like taking blood samples or biopsies: but I don't. Not if it's part of health maintenance or therapy, and doesn't expose someone to unreasonable risk.


Four Levels of Complexity

"...He breaks tissue-building into four levels of complexity.
  • "Flat structures, such as the skin, are the simplest to engineer as they are generally made up of just the one type of cell.
  • Tubes, such as blood vessels and urethras, which have two types of cells and act as a conduit.
  • Hollow non-tubular organs like the bladder and the stomach, which have more complex structures and functions.
  • Solid organs, such as the kidney, heart and liver, are the most complex to engineer. They are exponentially more complex, have many different cell types, and more challenges in the blood supply.
" 'We've been able to implant the first three in humans. We don't have any examples yet of solid organs in humans because its much more complex,' Dr Atala told the BBC...."
(James Gallagher, BBC News)
James Gallagher's article outlines Dr. Atala's technnique for growing bladders, one of the third-most-complex items from that list.

They start with a tissue sample from the bladder being repaired. The sample is about half the size of a U.K. postage stamp. A supply of cells is grown from that sample. The process takes about a month. Meanwhile, a scaffold or mold shaped like the bladder gets built.

Once they've got enough cells on hand, they coat the scaffold: one layer of cells at a time. The coated scaffold goes into what Mr. Gallagher called an oven for two weeks. Since the "oven" mimics conditions inside the human body, I'd think "aquarium" might be slightly more accurate.

Either way, after two weeks the bladder is ready to be implanted into the patient: scaffold and all. The patient's body eventually absorbs the scaffold, leaving a working bladder.

Bladders and Growing a Rat Heart

A bladder looks and acts like a balloon: sort of. What make growing a bladder tricky is getting the little spirals, lines, and circles of muscle fibers working properly; and connecting them to blood vessels and the parasymathetic nervous system.

The parasympathetic nervous system is part of the autonomic nervous system. We generally aren't aware of that part of our body's operating system, until something goes wrong: and that's another topic.

Alexis Carrel started growing a sample from a chicken embryo's heart January 17, 1929. He died November 5, 1944. The tissue lived until September 1946. So far, nobody's managed to repeat Carell's experiment.

But scientists are still learning. Dr Doris Taylor's team grew a rat's heart that kept beating for eight days. Granted, the heart worked at 2% capacity: but that it worked at all is remarkable.


Brand-New Tech, Same Old Challenges

I'm pretty sure that someone will find ways to misuse regenerative medicine. We humans have a knack for getting into trouble. "But man himself begets mischief, as sparks fly upward," as Job 5:7 puts it.

We also have a knack for evading responsibility: or trying to. After our first parents broke the deal they had with God, Adam tried blaming his wife: and God. (Genesis 3:12)

That didn't end well.

("Expulsion from the Garden of Eden," Thomas Cole, via Wikimedia Commons, used w/o permission.)

New Tech, New Rules, Same Old Principles

(Commercial ad of the Dormans of Stafford engine company in The Times, via Dormans and Wikimedia Commons, used w/o permission.)
(Ad in The Times, February 24, 1919.)

Back in my 'good old days,' a half-century back, some folks claimed that science and technology made the 'outmoded morality' we'd been working with obsolete.

Others apparently believed that moral decay was caused by newfangled gadgets like the telephone and television: and, of course, that 'religion of the antichrist,' evolution.

Folks who claimed that science and technology made 'conventional morality' obsolete were right: sort of.

For example, social conventions and laws that worked when a horse was the fastest thing on the road don't necessarily apply when you add motorized vehicles to the mix.

The United Kingdom's Locomotive Acts of the 1860s and 1870s, and their equivalents in America, weren't completely daft. We still have vehicle registration, registration plates, speed limits, and maximum vehicle weights.

Eventually, legislators realized that making automobiles stay below four miles an hour in the country, two miles an hour in cities, and have a man carrying a red flag walk in front of road vehicles hauling multiple wagons was — daft.

Some things haven't changed, though, and won't. For example, theft was wrong and aiding strangers was right in Abraham's day: and now. The Decalog wouldn't show until Moses' time, but I think we see hospitality as a virtue in Genesis 18 — and that's another topic.

Positive Law, Isus Positum: Human-Made Rules

The Roman Republic's five-tier status system worked pretty well. Someone could have status civitatis, status libertatis, status familiae, or be alieni iuris. We'd think there was a sixth tier, slaves: but they weren't persons, legally.

Remember, I said the Republic's system worked "pretty well." It wasn't perfect, but the Republic lasted for five centuries before the Senate bollixed things up to the point where they needed an emperor — and that's another topic.

The Roman Republic's laws and constitution are an example of ius positum, or positive law: human-made laws that define how folks may act, and what rights they have.

The 'conventional morality' that some folks got fed up with in 'the good old days' was positive law: something that folks who were mostly Anglo-Saxon Protestant men in America had concocted. Like Roman law, it had worked pretty well. But by the 1960s, parts of that set of positive law were long overdue for overhaul.

I do not miss living in a society where "she's as smart as a man" was supposed to be a compliment, and a person had to look like me to get a decent job. I remember the 'good old days:' and they weren't.

Natural Law, Lex Naturalis: Universal Principles, Changing Applications

Folks at least as far back as Plato and Aristotle discussed what we call natural law, lex naturalis.

I'm Catholic, so I accept St. Thomas Aquinas' idea that natural law is universal, unchanging, and designed by God.

Natural law is 'programmed' into us, part of reality that we can understand through reason. It lets us recognize good and evil, truth and lies. (Catechism, 1954)

Natural law does not change: doing evil so that good will follow is never acceptable; the Golden Rule always applies; we must always respect our neighbor, and our neighbor's conscience. (Matthew 7:12; Catechism, 1789, 1958)

How natural law is applied varies a great deal. Folks in different cultures and eras face different circumstances. But the underlying principles of natural law do not change. (Catechism, 1957)

The Catechism has a bit more to say about natural law: 1954-1960, 2259-2262, 2268-2270.

When our first parents decided to break God's rule we lost the harmony we had with God and with this world. But we were still human: made in the image of God, with dominion over this world — and the responsibility that goes with that power.

Are free to choose what we do, or do not do. Then, for good or ill, we live with the consequences of our decisions: and so do all generations that follow. 1

Living in 'The Future'

A few years or decades from now, we may be debating whether it's okay for someone to grow an extra brain, or marry his/her clone. Maybe that sounds like "science fiction," but —

I'm seeing my computer monitor through clip-on lenses, a surgeon replaced my original hip joints with metal-and-synthetic replacement parts, and my brain's neurochemistry is maintained by high-strength antidepressants. Although quite a bit of me artificial, I'm not quite a cyborg.

However, some of my internal and clip-on tech didn't exist when I was born, so I'm hardly in a position to rant about the supposed evils of science and technology.

I like being able to walk and think without fighting my body. That doesn't bother me, since the replacement parts and chemical tweaking are strictly therapeutic, the contemporary equivalent of licking a wound.

Maintaining or restoring health and normal function is okay. Making fitness or appearance my top priority: not so much. (Catechism, 2288-2291)

As I've said before, God gave us brains: and expects us to use them. (February 25, 2010)

I've been living in "the future" for quite a while now: and loving it. And that's — what else? Another topic. (February 9, 2014; June 14, 2013)

Yet more of my take on the importance of not being daft:
A bit of what the Church says about ethics and medicine:

1 You guessed it. There's more about free will in the Catechism: 31, 355-361, 373-379, 386-390, 396-409, 1730-1738, 1778, 2402.

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What's That Doing in a Nice Catholic Blog?

From time to time, a service that I use will display links to - odd - services and retailers.

I block a few of the more obvious dubious advertisers.

For example: psychic anything, numerology, mediums, and related practices are on the no-no list for Catholics. It has to do with the Church's stand on divination. I try to block those ads.

Sometime regrettable advertisements get through, anyway.

Bottom line? What that service displays reflects the local culture's norms, - not Catholic teaching.