Scientists Grow Blood Vessels Using Skin Cells

rubberbando writes "The new york times is running a story about how scientists have discovered a way to grow new blood vessels using skin cells. Since the blood vessels are grown using the patient's own skin cells, there isn't any chance for rejection. This looks to be quite a boon for people who have several damaged blood vessels from diseases such as diabetes. Perhaps one day they will be able to apply this technology/technique to creating other parts of the body and rid us of the whole stem cell controversy. Only time will tell."

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Article text for your convenience

[Karma Troll]

Blood Vessels Grown From Skin
By THE ASSOCIATED PRESS
Published: November 16, 2005

DALLAS, Nov. 15 (AP) - Two kidney dialysis patients from Argentina have received the world's first blood vessels grown in a laboratory dish from snippets of their own skin, a technique that doctors hope will someday offer a new source of arteries and veins for diabetics and other patients.

Scientists from Cytograft Tissue Engineering Inc., a small biotechnology company in Novato, Calif., reported the tissue-engineering advance on Tuesday at the annual conference of the American Heart Association here.

Dr. Elizabeth Nabel, director of the National Heart, Lung and Blood Institute, which has spent $2.5 million to finance the company's work, called the new method "extraordinarily promising."

Because it uses the patient's own tissue, the technique steers clears of the political and ethical debate surrounding embryonic stem cells.

Think about your breathing. Inhale. Exhale.

Like many patients in dialysis, the two Argentines, a 56-year-old woman and a 61-year-old man, were faced with the prospect of running out of healthy blood vessels. To grow new ones, doctors took a small piece of skin and a vein from the back of the hand, and nurtured them in a laboratory dish with growth enhancers to help produce substances like collagen and elastin, which give tissues their shape and texture.

The process produced two types of tissue: one that forms the tough structure or backbone of the vessel and one that lines it and helps it to function.

The feel of the new tissue "was very similar to the other vessels" that were present from birth, said Dr. Sergio Garrido, the surgeon who implanted it in the two patients.

The woman's new vessel has withstood needle punctures three times a week for six months and the man's for almost three months.

In the future, doctors hope the homegrown vessels will prevent amputations in diabetics who suffer from poor circulation, and give heart-bypass patients new veins or arteries to detour around blocked vessels. The method may also hold promise for children born with defective blood vessels

No controversy? Hah!

[TwentyLeaguesUnderLa]

I doubt that it'll rid us of the controversy... because by the time that becomes possible, cloning or genetic modification of some other sort will also have also become possible, and that'll just pick up where the stem cell controversy left off, probably with many of the same arguments on both sides.

Re:No controversy? Hah!

[Anonymous Coward]

There can still be a problem. People don't get blood transfusions because it's their religion.

That's not a problem. People have a right to refuse medical treatment. If they choose not to have a blood transfusion, that's their prerogative.

Now, when parents prevent their children from getting blood transfusions for religious reasons... that can pose a problem.

Re:Science!

[RootsLINUX]

I'm actually considering abandoning computer architecture (what I currently study in grad school) and heading into neuroscience, because I find that research so much more enlightening, practical, and useful. Well I have many more reasons, some of which are deeper than others, but if I could spend my life studying ways to ameliorate neurodegenrative diseases like Parkinsons, I'd find a whole lot more meaning in that then spending years and years to make a processor thats just 2% faster on only certain types of workloads.

Absolutely no offense intended towards you EEs/CmpEs out there (hell, at this moment I'm still one myself), but I just want my time to be more directly involved in helping people rather than helping companies make a bigger profit. Ya know what I mean?

Get rid of the stem cell controversy?

[ScentCone]

We can't get rid of something that's projected onto the situation by people who are nervous/scared about what the bio-sciences say about their world view. The stem cell worriers aren't really worried about stem cells or their source, they're worried about how close we're getting to a comfortable understanding of cellular mechanics. That takes the mystery out of a lot things, and devalues mystical explanations (and those social institutions that rely upon them for clout).

Growing new body parts out of other body parts will still freak out a certain number of people, no matter what. If it's not the stem cell faux-controversy, it will be the "only rich people can afford this treatment, so it's evil" crowd or their various other counterparts.

Re:Get rid of the stem cell controversy?

[Grym]

The stem cell worriers aren't really worried about stem cells or their source, they're worried about how close we're getting to a comfortable understanding of cellular mechanics.

Oh please... The debate over Stem cells has nothing to do with scientific understanding of cellular mechanics. If that were the case, Watson and Crick would have been burned at the stake decades ago. No other research involving cellular mechanics has reached this level of public scrutiny. I've never heard anyone debate the ethics of cell-surface recognition proteins or origins of the mitochondria in cells. Let's be honest. The whole stem-cell debate is merely a veiled front for the larger fight over abortion. (I use the word fight because "debate" hardly fits.)

Here's how it happened:

1. The most interesting and scientifically-valuable stem cells are found in developing embryos.
2. Studying these cells requires the destruction of the embryo.
3. This raises the ugly question: if destroying an embryo for research is okay, what makes an abortion any different?
4. Fight ensues. Everybody all the sudden becomes an expert on cellular biology.

That takes the mystery out of a lot things, and devalues mystical explanations (and those social institutions that rely upon them for clout).

Bullshit. "Social instiutions that rely on mystical explanations"? Do you mean "religions"? Why don't you just say it? ...Religions... See how easy that was?

Regardless, science doesn't debunk the larger, more important claims of religion. It can't. Learning about cellular theory doesn't debunk the existence of God. Learning physics doesn't mean that God couldn't temporarily violate the laws of physics at a whim--you know, being omnipotent and all.

Religion and God are meta-physical concepts, while science is the study of the physical world. The two aren't mutually exclusive ideas. A scientist can just as easily believe in a religion as an atheist in science.

-Grym

Re:Get rid of the stem cell controversy?

[ScentCone]

Let's be honest. The whole stem-cell debate is merely a veiled front for the larger fight over abortion.

I would contend that the more we know (and can demonstrate) about what's cooking, and when, in the development of a zygote, blastocyst, etc., the more we deflate some of the fuss about the abortion issue in the first place. It's important, I think, to make sure that those who assign humanity to, say, 16 cells (or to a dividing line of them derived therefrom) really have to come out and admit that it's a mystical, rather than medical position to take. It just sheds some purer light on the discussion (or, fight, as you rightly describe it).

Re:Get rid of the stem cell controversy?

[Proney]

Religion and God are meta-physical concepts, while science is the study of the physical world.
... as long as you aren't in Kansas.

Re:Get rid of the stem cell controversy?

[Guuge]

Religion and God are meta-physical concepts, while science is the study of the physical world. The two aren't mutually exclusive ideas. A scientist can just as easily believe in a religion as an atheist in science.

But can a contemporary evangelical Christian respect science as easily as an agnostic? Can someone who places an enormous value on the literal veracity of various myths really accept that some of those myths are false and the rest are untestable? The answer is being played out across the country, and so far it is a resounding NO.

hmm.. interesting...

[way2trivial]

there are surgeons who specialize (at least partly) in bloodless surgeries, as some folks have religious beliefs that deny them blood donated from others...

wonder how this tech gets interpreted by the religious leaders... permissible or no....

Meat factories

[backslashdot]

Maybe we can grow steak this way too .. in large vats. Get rid of the animal rights issues that way.

Yumm.

Re:Meat factories

[Loc_Dawg]

I'm a vegetarian, but I would more likely go back to real meat before eating this stuff.

Re:Meat factories

[QuantumG]

Personally I would love it if protein synthesis became plausible in my lifetime. First you'd sell these factories to third world countries where defending a corporate asset is a lot easier than defending farmland. Instantly curing world hunger. Then you'd see 100% synthesised meat alternatives appearing in vegetarian food outlets - there's already some of this, Quorn being the most famous, but their manufacturing methods are too expensive to have an effect on the mainstream. Then we'll see synthesised meat appearing in shopping centre refrigeration cabinets. When you have the choice between $21.99/kg steak vs $1.99/kg synthesised meat you'll at least give it a go. From there, the future is our playground. We can shut down factory farms. We can reclaim land for foresting. We can build self sufficient space habitates without needing to launch millions of tonnes of topsoil for crops.

Re:Meat factories

[vidarh]

Except for the fact that food production has been high enough to "cure world hunger" for decades. It is NOT a production problem, but a distribution problem (aka a problem of poor people not being able to pay for the food).

That problem will increase not decrease with what you are suggesting, as it will remove the livelyhood of millions of farmers in the third world that currently depend on being able to compete with larger scale farming or industrial food manufacture.

Want to solve world hunger in one "easy" step?

Drop agricultural subsidies in all developed countries and spend the money on providing farming tools and infrastructure in the developing countries instead, while gradually removing all trade barriers on exports from third world countries without forcing them to go first.

Yes, you'd have a rebellion of farmers on your hand, pissed off that they're suddenly having to deal with actual competition instead of being sheltered in every way possible. And yes, a lot of them would face going bankrupt. And yes, food prices would rise at least temporarily...

Which is why little ends up actually being done to stop world hunger - whichever way you look at it, it requires the third world to have more control over their own food supply, and the only way that will happen is to make it more profitable to farm there so that local farmers can afford to take precautions against droughts etc. (including building up grain caches etc.) - the volatility of food local food production is the main cause of hunger and famines today.

All of this WILL force farmers in the developed countries to have to make significant adjustments, and at the moment they're simply too powerful for any politicians to dare push that kind of agenda very hard.

Takes out the mystery?

[Nerdposeur]

The stem cell worriers aren't really worried about stem cells or their source, they're worried about how close we're getting to a comfortable understanding of cellular mechanics. That takes the mystery out of a lot things, and devalues mystical explanations (and those social institutions that rely upon them for clout).

I can't speak for everyone, but I have a problem with using fetuses for stem cell research, and none whatsoever with this. Medical science can do wonderful things for people (I look forward to when they sythesize blood and eliminate shortages); I just don't want other people to be trampled on in the process.

As for taking the mystery out of things, I think it's just the opposite. The more you understand the universe, the more wonderful it seems. I don't see how knowing the mechanics of cells creates an argument for atheism, as you seem to imply.

Re:Takes out the mystery?

[ScentCone]

The more you understand the universe, the more wonderful it seems.

We can definitely agree on that.

I don't see how knowing the mechanics of cells creates an argument for atheism, as you seem to imply.

Woops! On that we can definitely disagree.

I have a problem with using fetuses for stem cell research, and none whatsoever with this.

I'm glad you make the general distinction between the discussed procedure and other methods. But I hope you can also make the distinction between a collection of dividing cells in a dish and a human being. I'll stop here, because we might as well just play a recording.

Re:Takes out the mystery?

[ScentCone]

I challenge you to give a definition of when something starts to be 'human' that isn't completely arbitrary

It can be very hard to look at a complex organism and say, "that's human, or is about to be," but it's not hard at all to say what is not. A collection of cells that has no functioning higher nervous system is not human. A collection of cells that has no interconnected, differentiated neural tissue at all is absolutely not human (yet). Zygotes, blastocysts, etc., while eventually capable of developing into an embryo and a fetus, are not humans, and have no platform upon which - at that point - to hang "human-ness."

I realize that's more a description of what is not yet human, rather than an answer to your "when is it human" question. I don't need to sweat pinning down that moment, because I know that a dozen dividing cells are way, way on the non-human side of that transition, regardless of when I would identify it in a given fetus.

Re:Takes out the mystery?

[Trigun]

This may seem cold and crass, but think of life as a table. When does the table become a table? When the last coat of lacquer goes on the wood? When the carpenter decides to cut a tree down to carve the table out of? When he actually cuts the tree down? Somewhere inbetween?

We collectively have decided that it's when it's flat enough to put stuff on and not have it fall off. But the artist, might say that it became a table with the inspiration, and the rest was inevitable process. The purchaser might say that it's not a table until it is set up in his dining room. The carpenter might say that it was always a table, and he just removed it from its protective coating.

I think that a table is a table when it has a flat top, and can fufill its designed function. But I respect the carpenter's idea that it was always a table, and the purchaser's idea that it's not really a table until it is actually functioning as a table. I don't really listen to the artist, they're all pseudo batshit-crazy, but I nod and smile so as to get out of there without having to hear how the light reflects of the natural grains of the oak or some shit like that.

Changing any one of the actors ideas of what a table is, is a monumental task, and may never be done.

Re:Takes out the mystery?

[wulfhound]

If 'brain death' is the accepted measure for death, surely 'brain life' should be the accepted measure for life? A blastocyst doesn't even have nerve cells, never mind a brain.

Re:Takes out the mystery?

[mdwh2]

I think that a table is a table when it has a flat top, and can fufill its designed function. But I respect the carpenter's idea that it was always a table, and the purchaser's idea that it's not really a table until it is actually functioning as a table.

Rather, one should respect their right to hold a belief or have an idea. That doesn't mean I respect their idea. Especially if it's something like "An acorn is a table".

ScentCone's answer had this right - perhaps we can't draw a magic line where we suddenly go from "not a table" to "a table", but more importantly, we ought to be able to look at some earlier stages and say it most definitely wasn't a table then.

This may seem cold and crass, but think of life as a table.

And the biggest problem here (which people often forget) is that isn't about life at all. One side agrees that all cells are living, but simply being alive isn't what's important - rather it's being sentient. The other side also actually agrees that simply being alive isn't enough, since most people consider it ludicrous to suggest it's immoral to kill a blade of grass. Instead they have some other criterion, such as having human DNA (so a piece of human DNA on its own is more important than a living non-human mammal that shows some level of intelligence, for example).

So whilst we can't change someone's idea that an acorn counts as a table, we can argue about what features that are important. Is it important that we have a flat surface to put things on, or is it important that one day, something may grow into something and might be able to be made into something with a flat surface?

Re:Takes out the mystery?

[cagle_.25]

That's the problem ... I don't think of life as a table.

There's a good reason for that. Any object can undergo a process of creation, as you clearly elucidate. However, some processes take longer than others, and have clearer boundaries than others.

In the case of an embryo, there is a definite moment, spanning a few minutes, in which sperm and egg unite and become an organism. A genetically human, genetically distinct organism. At that point, from the legal standpoint that existed until Roe, all human organisms get the same basic rights: the right to not be killed by others, for example.

If you wish to argue that the embryo does not have that right, the burden of proof should reasonably be on you to show it, not simply to appeal to skepticism of the form "when does it become human, anyway?"

My $0.02

Re:Takes out the mystery?

[ScentCone]

based upon whether an X or Y carrying sperm has fertilized the egg

I'm using "she" as it is properly used - as a pronoun (as opposed to "it" or "they" since we're referring to a dozen cells in a dish). Of course the assembled DNA is the blueprint for a male or a female. But there's no "she" there, in that there's no anyone there yet.

Are you implying that the attaching is done by some third party?

No, I'm making the distinction between the nature of the interaction between the blastocyst and the uterine wall, and the implication that "she" is "doing" something - an implication designed to bolster the notion that there's this tiny little person cooperating in the reproductive process. There's no structure in the blastocyst capable forming the notion of an action, and no mechanism capable of carrying one out. Using language like "she does this" is highly misleading, and I'm calling you on it, that's all.

Yet we are not talking about ultimate origins of the matter we are talking about the origins of the individual human being.

Sorry, you can't separate the two. The same laws of physics govern ashes and cellular mechanics. If you're comfortable with the source of the underlying matter being non-supernatural, and then you should be comfortable with the normal behavior of that matter simply being what it is, and not assigning it a personality or meaning before it has the physical properties that support such sophistication.

Cells from my body will not develop on their own into another individual human being. On the other hand a blastocyst will.

One more time: you're looking through a microscope at a doezen cells sitting in a dish. Walk away, go to lunch, maybe dinner, too. That cluster of cells is not going to do anything on its own. It wouldn't even exist but for highly sophisticated processes and technology. It won't exist beyond that state without more of the same. Left alone, no nerves will grow, no movement will occur, noone can possibly be there to talk about.

So long as she is able to attach to a uterus (artificial or natural once the technology allows) so that she may obtain the nutrients she needs to continue growing.

Thank you for re-making my point. Once the technology allows, those millions of skin cells will have every bit the prospects of becoming an embryo as the refridgerated IVF leftovers. Since neither can possibly become an embryo without science doing its work, they will have exactly the same potential and moral value. If you really are willing to change your moral judgement on one versus the other based on just how far along the technology is, then you've got some pretty slippery underlying values. Not too many years ago, IVF wasn't around to produce any children. Some are probably now reading slashdot. Will children derived from other cells have less value to you? You might as well sort it out now, because it's coming. And once it's here, you won't have the luxury of telling me I'm ridiculous for comparing one potential source of an embryo to another in order to reinforce your notion that 11 more cells than one skin cell in a dish makes a human being.

Neither makes one. Not without technology. In the presence of technology, both will be indistinguishable, and you'll have to face the music: either 12 cells isn't a person, or one cell is. And then every time you shave it will be a moral dilemma. That dilemma is, of course, eliminated by thinking more rationally about where, in those twelve cells, there is or is not yet an actual human.

Re:Takes out the mystery?

[ScentCone]

You believe that a blastocyst in a dish is less human than a blastocyst in a womb.

Not at all. A blastocyst is a blastocyst regardless of where it is. A blastocyst embedded in the womb has a chance of developing into an embryo which has a chance - with enough differntiation and sophistication - at becoming a human fetus. A blastocyst in a dish so far (since we don't have effective artificial wombs) requires implantation so that it can develop, eventually, just like its more naturally fertalized counterparts. But it doesn't matter, because neither group of a dozen cells has in any way manifested itself as anything other than a dozen undifferentiated cells. That's not a human being - it's just something without which (at the moment) you can't make a human being. Prior to cloning of mammals, you couldn't make them without a sperm and an egg, either - but now you just need part of an egg, and the DNA from a good, workable cell. Those are building blocks, just like the blastocyst is a building block. A dozen cinderblocks in a row may be sitting there in accordance with a larger blueprint, but they're not a house. Yet.

A skin cell culture cannot of it's own volition become an adult human being

By which you mean that a blastocyst can by its own choice and action, do so?

Volition: noun.
1 : an act of making a choice or decision; also : a choice or decision made
2 : the power of choosing or determining : WILL

By what mechanism - in real, biological terms - are those 12 cells harboring the ability to sort through options and willfully act? Careful, your magical thinking is starting to show here, even in just your choice of words.

So, you take an egg, and artificially (outside the body) fertilize it with sperm, producing - after a few divisions, a blastocyst. That blastocyst cannot exist without the scientific process that just caused it to exist. Now, you take an egg, use DNA from a skin cell (replacing the egg's DNA - the only DNA in play, now, is that from the skin cell), re-set to the stem state, provoke division, and you've got (after the same number of divisions) another blastocyst which is indistinguishable from another of more convetional origins. This is the current/near-term state of things. The use of the convenient egg container (with its signaling mechanisms) can probably be dispensed with over time. Of course, neither the inserted-DNA version, nor the more "traditional" (um, if you can call a decade or two long enough to call anything traditional) IVF version have any prospect of eventually giving rise to an embryo without more medical support. But once they're latched into a receptive womb, you can start the embryonic clock ticking.

Which one is not human?

are a human being in the blastocyst stage of development and will become an adult human being if all conditions are ideal

Then by that standard, the egg and sperm of two people sitting across the table from each other are just as human - those two people are carrying around untold numbers of other humans, they just happen to be that very fragile "unfertilized" stage of development. They need the right circumstances to be present, but the potential is there - all of the ingredients are already ready to go. No science needed, just some candlelight (or too much beer, etc). If you consider 12 cells a person, then of course you consider that single fertalized egg a person. Of course, there's always the odds that the egg won't survive its first division. Just like there's always the odds that the sperm and egg won't fertilize successfully - but there's the material, the circumstances, and (usually) the will for them to be in the same place at the same time.

I don't consider a sperm and egg, a hundredth of a millimeter apart from one another, to be a human - just the building blocks. Hours later - when those building blocks have interacted and begun to divide into a dozen identical, undifferentiated other building blocks, you're

Re:Science!

[zoloto]

You know what I'd personally enjoy? Structural modifications of the not so visible kind. How cool would it be to have your major arteries "reinforced" with some sort of external metallic mesh? No more going for the jugular!

Even broader implications?

[Potato Battery]

The summary refers to conditions where vessels have been severely compromised, but I wonder if it can go even further. Vascular deterioration, and its role in overall CV ill-health is both part and parcel of modern America, and also contributes to the severity of other conditions. Having some way of replacing damaged vessels that is easier than current methods could find applications across the board.

The article doesn't give much detail, but I would think that generation of blood vessels that won't be rejected, if it could be refined and the costs driven down, could have a huge effect, especially if combined with new, lower-impact, surgical techniques.

Or, we could just stop eating junk.

Re:Even broader implications?

[Red Flayer]

The problem is that the vessels (and various CT) are grown ex utero and not on the capillary scale. They are no easier to transplant than donated or synthetic vessels... the only difference is the risk of rejection being close to zero.

Also, not eating junk won't help you if you're on dialysis... you're still getting poked with a needle at least weekly, which is the cause of the degradation.

Athletes?

[quark101]

With athletes always looking for a competitive edge, what could this kind of technology do to professional sports? It seems to me, if you can increase the blood flow to your vital muscles (sport dependent), then you would gain an enormous advantage over your opponents.

Will this be the next big sports controversy? And what could be done about it, if it doesn't use drugs, and is grown from the patient itself?

Re:As Usual....

[Scotty2]

That's wonderful for you... I don't read digg.

Stem cells don't come from babies

[MichaelPenne]

They come from blastocysts.

Which there are plenty of slowly expiring in vats of frozen nitrogen at fertility clinics around the world.

"if this thing takes off", those blastocysts will be saving people's lives instead of slowly rotting away.

Re:Stem cells don't come from babies

[Firethorn]

Hate to break it to you, but those people consider your blastocyst to be a living breathing baby. They like popping up pictures of 7-9 month term fetuses/babies on billboards.

Most of them don't mind harvesting 'stem cells' from any source that still results in a born baby (umbilical cords, for example).

Me, I don't care that much, but I can understand their views a bit better than most.

Re:Stem cells don't come from babies

[David Gould]

They come from blastocysts.

Which there are plenty of slowly expiring in vats of frozen nitrogen at fertility clinics around the world.

Hate to break it to you, but those people consider your blastocyst to be a living breathing baby. [...] Most of them don't mind harvesting 'stem cells' from any source that still results in a born baby (umbilical cords, for example).

Okay, I'm not saying you missed the point of the GP post -- I understand that you're just speaking for "those people". So would you mind answering one more argument on behalf of "them"? It's something that I've never heard an embryonic-stem-cell opponent answer, and I'm dying to hear what "they" would say. Here it is (worded in second person):

Did you miss the part about the "vats of frozen nitrogen at fertility clinics"? I mean, it's not like scientists are driving around poor neighborhoods, picking up pregnant teenaged girls, and persuading them to have abortions by offering to buy their embryos. No! Nobody would support that! These are the excess embryos created at fertility clinics in the course of in-vitro fertilization. Now, I understand that a right-to-life purist might still consider those excess embryos to be human babies, but in that case, you'd have to oppose IVF treatments every bit as vehemently as abortion.

Funny, I don't recall ever hearing of anti-abortionists picketing (or bombing) those clinics. So, is IVF okay or not? If it's not, then why aren't you opposing it to the same degree as abortion? Or if it is, then WTF is wrong with embryonic stem cells?

Re:Hope At Last

[segment]

lynx -dump "http://tinyurl.com/bsu7d" |sed -n '106p' |sed 's/est/ its/g;s/z/s/'|awk '{print $5,$7,$4}'

Re:Science!

[whitehatlurker]

what are you all doing to make the world a better place?

Ummm - I'm sitting here, reading slashdot ... doing that prevents me from being on the streets, which I think we can all agree makes the world a better place.

Re:Hope At Last

[benf_2004]

Psst...I think you mean MENSA

Some cancers do this, too.

[macklin01]

This has been done before--by cancer.

Just the other day in my cancer seminar (biomedical engineering department at UC Irvine), we were discussing angiogenesis, which ordinarily occurs when tumors have an imbalance between angiogenic growth factors and inhibitors. (Usually arises when tumors become too large to receive their nutrients soley from diffusion through the tissues.) The resulting gradient in these chemical signals recruits endotheial cells (the cells that ordinarily form the walls of blood vessels) to move chemotactically towards the tumor, align themselves, and form a new blood vessel to supply nutrients to the previously hypoxic tumor.

But in some tumors, the tumor cells themselves align and form blood vessels, with no need for endotheial cells. Much like forming blood vessels from skin cells.

The human body is truly an amazing machine. The fascinating part about cancer is that you get to see many of the mechanisms at play, and what happens when they're out of balance. -- Paul

Re:Some cancers do this, too.

[macklin01]

For the AC, here are some definitions:

angiogenesis: angio = blood vessels, genesis = creation, so angiogenesis is the creation of new blood vessels. adjective form: angiogenic

angiogenic growth factor: a chemical substance / signal that promotes angiogenesis

angiogenic inhibitor: a chemical substance / signal that inhibits angiogensis

gradient: in this context, a variation with a pronounced direction of increase

chemotaxis: chemo = chemicals, taxis = motion or moving, so chemotaxis is the (active) motion of something in response to chemoicals. usually involves a cell or organism moving from areas of a high chemical concentration to an area of low chemical concentration, or vice versa. adverb form: chemotactically

hypoxic: hypo = too little, oxic = oxygen, so hypoxic means being in a condition of having too little oxygen

Given the generally science-educated readership, I didn't give it earlier, although I perhaps should have. I used the terms because they have specific meanings, and the interesting aspect (one of balance) wouldn't have been as well conveyed without them. I'll grant that I could have done a better job writing my post, but it's only slashdot. ;-)

The thing that's interesting about all these chemical signals is that it's the precise balance of them that leads to the proper formation or blood vessels when called for. When the chemicals are out of balance, strange things happen, like blood vessels growing towards tumors. Another interesting aspect is that the balance of promoters and inhibitors for tumors is different than in the usual formation of blood vessels. This inbalance actually causes the blood vessels to be "leaky" and less rigid. The implications of this are too numerous to go into here, but chemotherapy is one thing that is (adversely) affected.

These balance issues are present in almost all aspects of how the body regulates itself. Cells are replete with redundant signaling pathways (different chains of events that can trigger a cell activity). Sometimes, multiple, contradictory pathways will be active at the same time, and the balance or imbalance will determine the net result. In another example, the balance and distribution of chemicals, hormones, nutrients determines whether a growing tooth becomes a molar or an incisor. (There was a Scientific American article on this a few months ago, in the context of growing tissues and organs from stem cells.) Again, the issue of balance. Fascinating stuff! :) -- Paul

Amazing

[Anonymous Coward]

Amazing. I've been advocating slashdot as a source of actual information for at least 8 years; I've come close to first post a few times. This time I thought I'd done it, and with what a post, the death notice of my sister, a brilliant young researcher in brain chemistry, one who treated Montel Williams. What a let down to read stupid jokes. Can't we all over this planet raise the level of discourse? My last words to her were that I wouuld not give the benefit of my brain to them. I am a physicist.

Re:Science!

[ozmanjusri]

what are you all doing to make the world a better place?

Well, last night I experimented with applied pharmacology and was able to make my part of the world into a much better place.

It was looking fairly seedy again this morning though, so I might have to repeat the dose. It's for the good of humanity, after all.