|
ISIS Report 04/10/10
Lab Study Establishes Glyphosate Link to
Birth Defects
Developmental
biologists traced glyphosate birth defects to key morphogen and signalling
genes Dr. Mae-Wan Ho
This report
has been submitted to the US Environment Protection Agency and the European Food
Safety Authority, please circulate widely to your political representatives and
demand a worldwide ban on glyphosate herbicides
Please circulate widely and repost, but you must give the URL of the original and preserve all the links back to articles on our website
Four-fold
increase in human birth defects prompted lab study
It started in
2002, two years after the large scale introduction of Roundup Ready soybeans to
Argentina [1]. People were reporting birth defects from exposure to
glyphosate sprays during pregnancy; and the problem got worse.
In regions where glyphosate-based herbicides are used, specific
neural defects and craniofacial malformations were reported. This prompted Prof.
Andrés Carrasco, director of the Laboratory of Molecular Embryology at the
University of Buenos Aires Medical School into action. He and his colleagues carried
out a laboratory study on the effects of glyphosate on the development of frog
embryos. They found the same kinds of abnormalities in frog embryos incubated
with a 5 000 fold diluted solution of the Roundup herbicide [2]. The findings
were so serious that Carrasco decided to release the results before publication
[3] (Glyphosate Herbicide Could
Cause Birth Defects Glyphosate
Herbicide Could Cause Birth Defects, SiS 43), and in May 2009, the
Environmental Lawyers Association of Argentina initiated a lawsuit to ban the
herbicide.
In April 2010, the first official report commissioned by the State
Government of Chaco documented a four-fold increase in both cancer and birth
defects in the ten years of 2000 - 2009 [4].
These findings are the latest addition to a long chain of evidence
linking glyphosate (and others herbicides) to serious
health impacts at concentrations well below the level of recommended
agricultural use. In the case of glyphosate herbicides, links to cancers,
miscarriages and other reproductive toxicities, liver and cell toxicities, DNA
damages, lethality to amphibians and endocrine disrupting action previously
made, would more than justify a worldwide ban ([5] (Ban Glyphosate
Herbicides Now, SiS 43); quite apart from simultaneous evidence of
ecological/agronomic disasters caused by the herbicide ([6] Scientists Reveal
Glyphosate Poisons Crops and Soil, SiS 47), while the spread of
glyphosate resistant weeds and superweeds has rendered the GM crop and the
herbicide practically useless ([7] GM Crops Facing
Meltdown in the USA, SiS 46).
Lab findings
in frog embryos parallel human abnormalities
In the first
experiment, Xenopus laevis (the African ‘clawed toad’, which is really a
frog) embryos were incubated with high dilutions of a commercial glyphosate
based herbicide (Roundup Classic, Monsanto). The embryos were exposed from the
2-cell stage with dilutions of the herbicide at 3 000-, 4 000-, and 5 000-fold
(the most dilute equivalent to 430 mm of glyphosate). They found highly abnormal
embryos in the regions of the head and central nervous system, and shortening
of the anterior-posterior axis, even at the highest dilution. These led to
deformities in the head cartilages at tadpole stage.
The second experiment indicated that the abnormalities were due to
the herbicide glyphosate rather than the adjuvants in the Roundup formulation. The
early frog embryos were injected with pure glyphosate, and they developed very
similar defects. Injection of glyphosate into one cell at the two cell stage showed
that the effects were restricted to the injected cell, with the non-injected
cell acting as a control (see Fig 1).
Figure 1 Effect of glyphosate injection; left to right: control
embryo not injected with glyphosate; embryo injected in one cells only; and
embryo injected in both cells
The researchers then treated chick embryos with glyphosate-based
herbicides and found similar defects. There was a gradual loss of head features
including the future eyes, and the embryos ended up with microcephaly (small
head).
Embryonic
defect traced to over active retinoic acid and expression of key developmental
genes
To pin down the
effect of glyphosate further, a reporter gene assay was carried out, which revealed
that glyphosate treatment increased retinoic acid (RA) activity in the frog embryos.
RA is an oxidized form of vitamin A well-known to have an important role in
determining the anterior and posterior axis in embryonic development. That is
why excess intake of vitamin A during pregnancy is advised against, as it can cause
birth defects.
As consistent with glyphosate causing the malformations through
increasing RA activity, the RA antagonist (Ro 41-5253) rescued (prevented) the
teratogenic effect of glyphosate.
A previous study had indicated that women exposed during pregnancy
to herbicides delivered offspring with congenital malformations, including
microcephaly, anencephaly (no head), and cranial (head skeleton) malformations
[8].
The increase in RA activity caused by glyphosate herbicides is also
consistent with the decrease in expression of several genes in the abnormal embryos:
Sonic hedgehog (Shh) signalling from the embryonic dorsal midline and otx2.
In humans, shh deficiency is associated with a
holoprosencephaly syndrome (failure of forebrain development into two lobes),
with a frequency of 1/250 of pregnancies and 1/10 000 of live births. Failure
of Shh signalling is associated with head and face abnormalities in mice,
zebrafish and the chick.
An excess of RA is also known to down regulate otx2 expression
in Xenopus, chicken and mouse embryos. Otx2 in turn is necessary
for the expression of shh in the ventral midbrain. All the evidence
indicates that RA signalling, otx2, and shh are part of a genetic
cascade critical for the development of the brain and craniofacial skeleton.
Glyphosate inhibits the anterior expression of shh, reduces the domain
of otx2, prevents the subdivision of the eye field (see Fig. 1), and
impairs craniofacial development.
Sublethal
doses of the herbicide (430 mM of glyphosate in 1/ 5 000 dilution of the glyphosate based
herbicide and injections leading to a final concentration of 8 to 12 mM of glyphosate
in the injected side of the embryo were sufficient to induce serious
disturbances in the expression of otx2 and shh and other genes.
These molecular phenotypes were correlated with a disruption of developmental
mechanisms involving the neural crest, embryonic dorsal midline formation and head
patterning.
Death and
destruction by multiple poisoning
So how does glyphosate
increase RA in the embryo to trigger the series of gene expression and
developmental abnormalities?
RA activity
is regulated by the degradation of RA by the CYP26 enzymes, these enzymes are
members of the cytochrome P450 family (same as aromatase, which glyphosate
inhibits). So it is possible that glyphosate increases RA by inhibiting the
enzyme that degrades RA.
Actually, glyphosate is a generalized chelator (binder) of metal
ions with systemic effects on many key enzymes that depend on multivalent ions
(see [9] Glyphosate Tolerant
Crops Bring Diseases and Death, SiS 47). As cytochromes are iron-containing
heme-based enzymes, it would not be surprising if glyphosate inhibits RA
degradation through binding the heme-iron. What is becoming clear is that
glyphosate can poison crops, soils, wild life, livestock, human beings and the
entire ecosystem in multiple systemic ways, and a global ban is long overdue.
References
1.
Groundbreaking study shows Roundup link to birth
defects, 16 September, 2010,
http://www.gmwatch.org/index.php?option=com_content&view=article&id=12491
2.
Paganelli A, Gnazzo V, Acosta H, Lopez SL and
Carrasco AD. Glyphosate-based herbicides produce teratogenic effects on
vertebrates by impairing retinoic acid signalling. Chem Res Toxicol, August 9. http://pubs.acs.org/doi/abs/10.1021/tx1001749
3.
Ho MW. Glyphosate
herbicide could cause birth defects. Science in Society 43,
36, 2009.
4.
Chaco government report confirms link between
glyphosate/agrochemicals and cancer/birth defects in Argentina
http://www.gmwatch.eu/index.php?option=com_content&view=article&id=12481:reports-official-report-confirms-correlation
5.
Ho MW. Ban glyphosate herbicides now.
Scientists confirm potent hormone disrupting effects. Science in Society 43,
34-35, 2009.
6.
Ho MW. Scientists reveal glyphosate poisons
crops & soil, GM meltdown continues. Science in Society 47,
10-11, 2010.
7.
Ho MW. GM crops facing meltdown in the USA. Science in Society 46, 24-27,
2010.
8.
Benitez LS, Macchi MA and Acosta M.
Malformaciones Congénitas associadas a agrotóxicos. Arch Pediatr Drug
2009, 80, 237-47.
9.
Ho MW and Cherry B. Glyphosate tolerant crops
bring diseases and death. Science in Society 47,
12-15, 2010.
|
There are 7 comments on this article so far. Add your comment
| S. Allen Comment left 16th October 2010 10:10:41
Councils have a 'Duty of Care', that means if they spray a public place they have to go beyond standard procedures to ensure the publics safety. Should councils breach their 'Duty of Care' it may be very costly for them in court. They may also face charges of misconduct from the CMC [ CRIME AND MISCONDUCT COMMISION ]. Don't let them get away with it. Send letters to the editor. Ask your local newspaper how to write your letters so as they can print them without fear of being sued. Take photos for evidence Good Luck | Dianne Comment left 5th October 2010 15:03:27
10 years ago, i presented a report to my local council about Roundup from the research that was available. I have Multiple Chemical Sensitivity and when the council sprayed, I would end up so sick. They ignored my health effects, they also ignored the research I presented and kept using it. Even with this information, studies showing it causes cancer & birth defects, they will continue to keep using it, until someone bans it. They just dont believe the studies - WHY? | David R.(Canada) Comment left 5th October 2010 08:08:18
It sounds like these guys in Brazil have gone to an extreem to prove their point! Dotted all the i's and crossed all the t's. And about time too.
It'll be very interesting to see how the media and Monsanto et al are going to spin this one!
Hopefully this will end the GMO debate quickly as it will no longer be profitable to grow them.
But of course they're moving into GMO animals (eg salmon) now so we'll have to wait for that one to blow up in their face. | Alex Comment left 4th November 2011 11:11:53
Is this considered a scholarly journal? | Sue Ross Comment left 14th March 2012 08:08:30
Concerend about our community garden being sprayed with roundup bio active. Could this behazardous? | Mae-Wan Ho Comment left 14th March 2012 08:08:54
Sue Ross, Please stop that spraying right away! It could be very hazardous indeed. | Jennifer Hutchison Comment left 3rd September 2012 17:05:48
My son has a "rare" neuromigrational disorder called Lissencephaly. In his case it is a result of a missense mutation on X. I find it interesting that some states in the US have many cases of this malformation as well as holoprosencephaly, anacephaly, and various assortments of malformations like agenesis of corpus callosum. I was raised in MI. It is wildy common there as well as PA, CA, TX, MO, KS, OH, UT (more common to have microcephaly and deteriorating grey matter from unknown causes. All of these states have heavy GM pharming and hydrofracking. I am assured that it is a coincidence and NOT because I grew up between Dow and Upjohn and downwind of Michigan State's experimental farms. I am not so sure. 1 in 250,000 live births yet I personally know 50 families just in western Michigan with children with this rare malformation. Not to fear- common forms of lissencephaly on chromosome 17 and X are being re-expressed thru redundancies : P Thanks, but no thanks science.
|
| |
|
