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September 4, 2010 12:00 PM   Subscribe

Three newly approved 'in vitro' toxicity tests using artificial human skin are reducing the need for animal testing of cosmetics and chemicals.

"...on July 22 ... the Organization for Economic Cooperation and Development (OECD) — an international group that, among other things, provides guidelines to its 32-member countries on methods to assess chemical safety—officially approved three commercially available in vitro models of human skin for use in chemical testing. Specifically, the new guideline (OECD Test No. 439) stipulates that the models can serve as an alternative to animals in tests for skin irritation, one of several human health endpoints for which chemicals are tested. Similar 3-D models were approved for corrosion tests in 2004, leaving many hopeful that soon it may be possible to the assess the full spectrum of a chemical's effects on human skin—from irritation to corrosion—without using live animals."
posted by zarq (10 comments total) 3 users marked this as a favorite

 
The "GOOD" blog has a nice explanation, but I didn't put it in the post because I wasn't sure if one of its claims was accurate. Specifically: "Many chemicals, we now know, can penetrate the skin. Some, if they are small enough, can even get into cells and alter DNA."

Obviously some chemicals can penetrate the skin. But can they alter DNA?
posted by zarq at 12:02 PM on September 4, 2010


zarq: Obviously some chemicals can penetrate the skin. But can they alter DNA?

From Wikipedia:
  • Some mutagens act as base analogs and get inserted into the DNA strand during replication in place of the substrates.
  • Some react with DNA and cause structural changes that lead to miscopying of the template strand when the DNA is replicated.
  • Some work indirectly by causing the cells to synthesize chemicals that have the direct mutagenic effect.
And yeah, there are plenty of mutagenic chemicals.
posted by JiBB at 12:23 PM on September 4, 2010 [1 favorite]


Ah, thank you for the explanation JiBB. Much appreciated.
posted by zarq at 12:41 PM on September 4, 2010


I think it's just a really inane way for GOOD to say 'mutagenic' and imply 'carcinogenic', zarq.

It's frustrating when authors do that, because sometimes potential mutagenic properties are overshadowed by other unpleasant consequences. But you mention potential mutagenic properties, and everyone flips out. Truthfully, if I'm gonna be involved in a spill exposure in the lab, and I get to choose the agent, I'd take ethidium bromide over pretty much any other treat-like-serious-bizness chemical I've worked with except distilled water.

At any rate, I'm going to be really interested to see how well these products do. I hope they do well, though the last page and a half of the article lay out some significant shortcomings. False positives are expensive, but not as concerning to me as not flagging known corrosive agents. Sure, it's not going to be perfect and catch everything, but it's concerning that the substances involved didn't even flag as 'irritants.' I'm going to have to look up which substances the artificial skin missed.

For another thing, if William Stokes--this is a 2000 article on approval for a different alternative to irritant testing--is expressing concern about the technology at this point, I'm inclined to be wary. That man knows his stuff.
posted by Uniformitarianism Now! at 1:35 PM on September 4, 2010 [3 favorites]


Okay, preview fail. We're not so paranoid that we treat distilled water like serious bizness. Unless someone left it in an unlabeled container, and then I make no promises, because I've (literally) been burned before.
posted by Uniformitarianism Now! at 1:38 PM on September 4, 2010 [2 favorites]


...the "need" for animal testing of cosmetics...

FTFY
posted by DU at 2:30 PM on September 4, 2010 [1 favorite]


Some, if they are small enough, can even get into cells and alter DNA."

The inaccurate part of this is that typically, size has noting to do with it. Members of the joint chiefs of staff can get into many facilities that I can not. And while I may be physically larger than all of them, it's the guards and stuff that are going to be the deciding factor.

If something bad looks enough like something on the guest list, all those cellular mechanisms that do things like maintain homeostasis won't have a clue and in it goes. If it were just a size issue, this would be pretty easy to predict.

In the area of chemistry, Good seems to embrace "little learning is a dangerous thing" like a long lost brother. For example, in one of the links from the one in the FPP, they bemoan the fact that ionic surfactants will strip out natural oils out of your hair. Yes, that's why they put them in there! Tell people you never use any soaps or detergents on your hair and see how they react.

Disclaimer: I went a couple years using noting but hot water and a natural bristle brush on my (shoulder length) hair. It looked great, but hair maintenance took about four times as long. When I started doing some serious rehab work on the house I couldn't keep up any more. So while I may be one of those cavalier scientist types, I'm a big hairy hippie freak cavalier scientist type.
posted by Kid Charlemagne at 3:30 PM on September 4, 2010 [3 favorites]


A lot of "mutagenic stuff" can get inside bacteria and fuck with their DNA. We (well, terrestrial animals/mammals) have an epidermis which can soak up a lot of these "stuff." In small quantities these just can't get to where they can do any cancer-causing stuff.

In a post from here or another popular aggregator, there was a link to a message thread about crazy chem accidents; one of the, later and extremely weak, posts in the thread was about some girl picking up a ethidium bromide infused agarose gel for electrophoretically separating DNA with her bare hands and, omg wtf bbq she's gonna get cancer!!!one!. Ethidium bromide is a DNA intercallator and could theoretically mess up DNA replication - ie., make a cancerous cell - and does mutate bacteria in rates high enough to make one-in-some-really-high-number able to revert a mutation that was engineered by humans so they can't survive without human help. (See Ames Test) In practice (and theory), EtBr is way too polar and bulky to get into human epithelial (skin) cells much less get past them into replicating cells of which could potentially turn cancerous.

Sure, drinking EtBr in milkshakes will probably give you stomache/intestinal cancer (these cells live to absorb stuff), but touching an agarose gel with EtBr without gloves isn't going to make your fingers rot away in gangrenous cancer.

THIS particular thing? I'm expecting lawsuits in the near future. Models won't can't tell you if there are people who will develop an immune response to whatever mixture of compounds that you want to put on people's skin, and that's not even counting the potential bad responses of individuals to a particular ingredient in the formulation.

I disagree with testing cosmetics on animals (I've seen the propoganda videos of forcibly dropping stuff in rabbit's eyes), but actual animal testing isn't like that. A lot of it is more testing for dermal sensitivity; shave a patch of fur, apply chemical/formulation/final product and then check some time later if there is a negative reaction.

Are people really against using animals in testing because... it's for a trivial (relatively) reason like cosmetics? What about using animals to test the efficacy/side-effects of drugs? Insulin (for diabeties) and penicillin (antibiotic) were first tested in animals (dogs, iirc)... if we didn't use animals for that research, how many anti-animal-testing advocates would be alive/born today?
posted by porpoise at 12:00 AM on September 5, 2010


Are people really against using animals in testing because... it's for a trivial (relatively) reason like cosmetics?

It depends; some people are absolutely against using animals because they see animals (most mammals, anyway) as having their own lives, experiences, etc, and that by using them for experimentation we are treating them as a resource instead of sentient entities. Other people go "ick! not on bunnies!" and yet other people go "wtf? for lipstick?" like you suggest.
posted by beerbajay at 5:35 AM on September 5, 2010


Science!
posted by Mental Wimp at 12:46 PM on September 5, 2010


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