Victims of childhood abuse can carry chemical changes to their DNA into adulthood.PunchstockPosted on 02/23/2009 1:34:04 AM PST by neverdem
Victims of childhood abuse can carry chemical changes to their DNA into adulthood.PunchstockSuicide victims with a history of abuse during childhood are more likely to carry chemical changes to their DNA that could affect how they respond to stress as adults, a study has found.
Those with no history of childhood abuse did not show the same pattern of DNA modification, and had normal expression of NR3C1, a gene linked to stress responses.
But the findings do not mean that the effect of childhood abuse is indelible, cautions Joan Kaufman, a psychologist at Yale School of Medicine in New Haven, Connecticut, who was not involved in the new study. "The long-term effects of early abuse are not inevitable," she says, "and the more you understand about the mechanisms of risk, the more you can devise treatments."
The results, reported today in Nature Neuroscience1, follow on from work showing that rat pups that are stressed because they were raised by negligent mothers have extra methyl groups in their DNA in a region of the genome that controls expression of Nr3c1, the equivalent gene in rats. Such 'methylation' can reduce gene expression. NR3C1 encodes a protein expressed in neurons that responds to hormones called glucocorticoids. Lower expression of NR3C1 could be harmful because reduced responses to these glucocorticoids have been linked to increased stress.
To find out whether the results in rodents translated into humans, neurobiologist Michael Meaney of McGill University in Montreal, Canada, and his colleagues collected brain samples from the Quebec Suicide Brain Bank. The researchers looked at samples from 12 suicide victims with a history of childhood abuse, 12 suicide victims with no history of childhood abuse, and 12 controls who had died suddenly from other causes.
People with a history of childhood abuse had lower levels of glucocorticoid receptors than either people who had not been abused or those who had not committed suicide. And childhood-abuse victims had a similar methylation pattern to that seen in rats that had been stressed as pups.
These changes are unlikely to be passed on to the next generation, notes Meaney. Although researchers have not yet looked for effects on egg or sperm DNA, it is doubtful that the changes affect the germline, he says.
Researchers do not yet know whether trauma as an adult produces the same pattern of changes. There may be times during childhood when the developing brain is particularly responsive to abuse, explains Martin Teicher, director of the Developmental Biopsychiatry Research Program at Harvard Medical School in Belmont, Massachusetts. Teicher and his collaborators imaged the brains of women who had been victims of child abuse and found that those who were abused between the ages of three and five, or eleven and thirteen, had a smaller hippocampus — a region in the brain that is important for memory and learning — than those who had not been abused2.
Studies in rats have also suggested that the methylation changes can be reversed: if pups reared by negligent mothers are later treated with a chemical that removes DNA methylation, their stress responses return to normal3.
Victims of childhood abuse can carry chemical changes to their DNA into adulthood.PunchstockSuch drugs are not ready for use in humans, and could carry unwanted side effects. But medication may not be the only way to treat victims of child abuse, and DNA methylation was restored to normal in neglected rat pups if those pups were transferred to more attentive mothers. "Just because there's a biological effect doesn't mean the only way you can intervene with drugs," says Kaufman.
Psychotherapy, for instance, has been shown to produce chemical changes in the brain, and might be able to reset the methylation pattern, says Meaney. "A social event got you into it. Could a social event get you back out?", he asks. "That's a very viable hypothesis."
May I please have a sheep?
[I’m evading your excellent post....LOL!]
great post, thanks.
Thanks for the ping. This is an important article.
Bookmark.
(Oh, wait! Counter transference. Dang! I got hooked again!)
Apparently, the things that happen within an individual's life can affect their DNA. Maybe Lamarck wasn't so wrong!
Oh, look!
A butterfly!
[countering counter transference with diversion]
;]
I have goats.
[random, semi-relevant interjection]
Gosh, you’re welcome...:)
Is the effect most pronounced in children, or does it affect adults?
Are there other neuro-receptors which can get methylated due to chronic stress?
(I'm thinking here of having to endure MSNBC, or getting stuck in rush hour every day...)
Cheers!
Okay. Rule out ADHD. refer to MD Shrink. Recommend serious drugs. (Ssk for my share.)
Goats are da BOMB! In my more psychotic moments I think of getting a couple of Nubians and milking again. They are WAY more fun than sheep.
They are SO smart it's scary....:))
This is "Baa", a wether.
This is "Spike" as a little baby
Baa was a rescue and he bonded to my geese which I thought was demeaning and pitiful for him so we bought Spike so he'd have "real goat" company.
They adore each other....:)
Baa has delusions of grandeur and fancies himself a mighty mountain goat.
Spike has delusions of being a lap dog and if I sit down anywhere near her, she will sit down by me and cuddle up companionably, with her sweet little chin resting on my shoulder.
[Obviously, I adore them]...:)
Oops! I forgot to address the ADHD.
Look!
Another butterfly!
Gotta go chase it! See ya!
....;-D
Epigenetic "changes" to DNA (as I understand them, and I have no expertise in this field whatsoever) are not changes to the DNA proper, but rather changes to the way the DNA expresses itself. These changes, however, can in some cases be inherited, albeit perhaps only for a few generations. I do not know whether or not that happens in this instance. I would be doubtful.
It’s still hard to believe that high level interpretations of sensory experience, such as “abuse”, could lead to such deep chemical alterations at the celluar level.
I have no idea if the author's hypothesis is correct or not. It certainly does arouse one's curiousity.
I find the whole field of epigenetics fascinating. I wonder if all that DNA that "does nothing" has possible uses after all. One of the purported flaws in the theory of evolution cited by its more thoughtful critics is that even the billions of years available for life to evolve into its current forms is not sufficient time for the DNA to alter by way of random mutations alone. Epigenetics could refute that argument (assuming the argument has merit in the first place).
For example, suppose future humans had use for a prehensile caudal appendage. We know that some humans are born with a tail. Could environmental stresses of precisely the right type "wake up" dormant existing genes to cause embryonic humans to grow prehensile tails? Alterations of form by this mechanism would be far faster than random mutations.
It would be sort of like Mother Nature saying, "Well , we worked all this out the hard way long ago, and kept it stored in the "useless" part of your DNA just in case it might be needed again." This could "speed up" evolution enormously.
Again, I am no expert in this field. This is just speculation on my part.
When the researchers produced a correlation between birth order and homosexuality in males, they were definitely tapping into methylation.
This finding on stress is not at all surprising.
Given that methylation is inheritable it's possible that there's some process we'll eventually discover that "converts" these exterinal, or epigenitic changes, into modifications to the genes themselves creating entirely new alleles.
Guys studying this stuff have to be pole vaulting all over the lab these days.
Believe me, there are some really nasty side effects with this problem. On the other hand wounds don't swell as bad, which is good.
I think you're confusing a symptom with a cause.
Chronic rhinitis then becomes part of the process ~ you secret liquids that carry the germs and other contaminants away.
BTW, you can lose your type E antibodies very easily ~
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