Growing
up, I remember my grandfather suffering from Parkinson's disease. Most people
reading this probably know someone who has Parkinson's disease. If this is the case, you may be aware that there are not many forms of treatment for this disease. However, progress is being made in this direction.
There
are not many treatments present for this disease other than medications that
are used to treat the symptoms caused by it. This is because it is difficult to test different
types of treatments since there are not many animal models that display symptoms similar to Parkinson's disease in which
medications can be tested for future use in humans.
Parkinson's
disease is known to be related to degeneration of neurons that release and
receive dopamine in the substantia nigra, a brain structure located in the
midbrain. Parkinson's disease typically causes symptoms including tremors,
rigidity, bradykinesia (decreased bodily movement), and postural instability. As
more research is being done, it is becoming more clear that there is a
genetic link to Parkinson's disease. However, there seems to be an interaction
between certain underlying genetic predispositions and environmental exposures
that leads to an increased rate of Parkinson's disease. Liu et al. looked at
the effect of a pesticide called rotenone on mice in order to create another
animal model in which we can observe different symptoms of Parkinson's disease.
Most
people consider insecticides, pesticides, and piscicides beneficial in that they help prevent many insects
from destroying farm crops that are being grown. While most people are aware
that many of them are harmful to us, it may come as a surprise that exposure to
certain insecticides can increase the rates of diseases such as
Parkinson's disease. Early exposure can cause damage to brain structures that
are related to Parkinson's disease. Further research may find links to other
environmental exposures as well.
The study performed looked at the effect of contact with rotenone, a compound
found in insecticides, pesticides, and piscicides (a chemical that is poisonous
to fish), on the development of Parkinson's disease. In the study, mice were
placed in a cage with a solution containing rotenone applied to the bottom. The
mice were kept in this cage for 2 hours a day before being returned to their
normal, rotenone-free cages. This was an attempt to simulate common forms of
exposure to many insecticides, pesticides, and piscicides.
They
found that exposure to rotenone did not affect body weight or cause systemic
toxicity. However, they did find that there were impairments in motor function,
a decreased amount of dopamine in structures of the brain, and accumulations of
α-synuclein, a protein that has been found to aggregate into "Lewy
bodies" which are known to be related to Parkinson's disease. Some of the mice that received high amounts of exposure even died! This showed
that exposure to rotenone produces behavioral and neurological changes similar
to those seen in Parkinson's disease.
This
study is very important because it provides another animal model in which we
can produce symptoms similar to what develop in Parkinson's disease. Going forward, hopefully more animals will be studied as well as other common compounds
present in different pesticides. This could lead to further insight on whether the
benefits of these pesticides outweigh the harmful side effects as well as learn more about their impact on the development of different animals. Also, it would
be interesting to see if changing the time of development in which the exposure
occurs has an impact on the affects the compound has.
Eventually, the goal would be to test new
medications or other treatments to improve both the symptoms caused by
Parkinson's disease as well as to treat the actual disease directly. While this may still be awhile away, studies such as
these show that research is still progressing and that more information is
being discovered every day.
Works Cited
Liu, Y., Sun, J., Song, L., Li, J.,
Chu, S., Yuan, Y., & Chen, N. (2015). Environment-contact administration of
rotenone: A new rodent model of Parkinson's disease. Behavioural Brain Research, 294, 149-161.
I think an interesting follow up to this study would be, like you mentioned, introducing mice at different stages of development to the rotenone (or a different compound found in insecticides, pesticides, and piscicides). Our generation and the generations after us will have significantly higher exposure to toxins like pesticides than those before us. Toxins often have high binding affinities for certain pathways in our body and can lead to endocrine disruption and the development of various disorders.
ReplyDeleteHi Gregory,
ReplyDeleteThis seems to be a decent model to study the mechanisms of Parkinson's disease. I'm confused though - if the drug didn't cause toxicity, but some mice died - what is thought to be the cause? Also, what age were the mice? As Natalie noted, learning more about development may be interesting. However, if the plan is to use this as a mouse model, it may also be important to pick a time course used so that other work can be compared across studies.
This comment has been removed by the author.
ReplyDeleteWhat are some of the few treatments that are available to treat Parkinson's disease? It is a bit scary how pesticides could cause Parkinson's disease, especially if there is no cure for it? Are there other environmental factors that could cause this disease such as pollution, temperature, exposure to sunlight, pH, etc.? I wonder if there are other compounds besides rotenone found in insecticides, pesticides, and piscicides that could also be contributing to neurological and behavioral changes. Isn't everyone at risk of developing Parkinson's disease since so much of our produce is being covered with chemicals to prevent plant disease and deter animals? It would be interesting to see this experiment conducted on other animals in order to compare results. This article makes me worried for the future if we don't find an alternative way of successfully growing crops without the use of pesticides.
ReplyDeleteParkinson's is a scary disease. My grandfather has been affected by this disease for almost 5 years now. It's pretty worrisome to see the disease progress, in some cases very rapidly. Carbidopa-levodopa is a very common drug used to treat Parkinson's and can often reduce the tremors, stiffness and slowness involved with the disease. But, like you had stated there aren't many treatments available, especially if the common medications do not help you. It is very scary that something everyone of us come into contact with on a daily basis can cause this terrible disease. Most people know pesticides are bad for us but it would be beneficial for information like this to get spread more publicly. Our environment can have very harmful affects on our bodies. This is a fact that many people either aren't aware of or choose to ignore. I hope that Parkinson's disease will continue to be researched, more treatments will be discovered and eventually a cure will be discovered.
ReplyDeleteGrowing up on a farm, I've been exposed to pesticides all my life. It's a scary thought that they can be so harmful, but like it or not they are a necessity in food production. Without them there would be no way for us to produce enough food for livestock or other humans. I find it interesting that a pesticide was used to induce Parkinson's-like symptoms in mice. How long did it take for them to come down with these symptoms after initial exposure? I was also wondering, if this similarity was just recently discovered, how did we test Parkinson's drugs before? This would be great if we could learn more about Parkinson's from these mice. These mice do not have Parkinson's though, only the symptoms. Do we know what is causing these symptoms? If we don't know that the mouse symptoms are caused by the same thing as the human symptoms how do we know that the drugs we test on mice will do anything when tested in humans?
ReplyDeleteI don't see pesticides going away any time soon because of how easy it makes our lives, especially during the 21st century where people are trying to maximize their times in the most efficient of ways. I resonate with the comments that Dan made above, as the farms that are distributing great quantities of food and they would have no other ways to allocate the products we receive from these farms. I'm interested if you came across any other articles that used mice as model organisms especially in relevance with the symptoms of Parkinson's disease? Do you know how the pharmaceutical industries will regulate these drugs once the reach the further phases of testing? One final thing, I think is important to consider is how far the mice were in development when this study took place as it could lead to further questions about the disease and the relevance it may have for humans. This was a very interesting article, and I'm sure that all of us understand how a person can truly change once symptoms of this disease surface in an individual.
ReplyDeleteThis is a very interesting topic! Parkinson's disease and many diseases such as different types of cancers seem to be affiliated with toxins that are attained from the environment. It seems that most of the time, a disease is acquired through genetic and environmental effects. To further enhance this study, researchers should obtain a survey finding out the different environments that people are living in and the percentage of the different populations who have Parkinson's Disease, such as farmers, who are around pesticides versus people who work in offices.
ReplyDeleteIt is scary that chemicals used widespread and in large amounts could potentially be linked to Parkinson's. I used to work in the garden section of Lowe's and I cannot even count how many customers a day would come in looking for some sort of pesticide/insecticide. Some of them would ask which one was the safest but there really aren't many "safe" pesticides. I bet if they knew it could be a potential cause of Parkinson's Disease they would be more skeptical. If further research proved this link to be true, more people can be educated on the subject, which would hopefully lead them away from using these products. I know these chemicals are pretty much unavoidable in certain situations such as agriculture, but I think some people turn to them much too quickly. I wonder to what degree of exposure would be considered dangerous.
ReplyDeleteI really enjoyed reading your post. These kind of discoveries and new possibilities make me excited for all the good that can come from science. I was not aware that the lack of treatment options for Parkinson's was partially due to the fact that we lacked animal testing models that could successfully recreate either the disease or at least its symptoms. As you said above the genetic link to Parkinson's has become more clear overtime with research, this makes it even harder to recreate this disease in test animals. But this new discovery of possible environmental influences has opened a new door in testing and is obviously not curing the disease but is definitely taking steps in the right direction.
ReplyDeleteThe findings of this study are very alarming! I feel that information such as this, even tough the findings are still rough and not quite solidified, is still something that every consumer needs to be made aware of. Personally, I always fight that internal battle while in the grocery store, do I risk it by going with produce that has been treated with pesticides, or do I spring for organic, which can be quite pricey. After reading the findings of this research I definitely feel that spending a couple extra dollars on organic every time I shop would most definitely be worth it in the long run as far as my health is concerned. You did mention that Parkinson's is being increasingly recognized as a genetic disease. Do you think then that the pesticides, specifically rotenone, would somehow be able to cause mutations in the germ cells of the people who ingest them, leading to the genetic inheritance of the disease? Or another explanation might be that some people just have a genetic predisposition that makes them more susceptible to the effects of the pesticides.
ReplyDeleteThis study seems very interesting and is a good topic to look at. Mice were a great idea for a model organism because in other classes I have learned that they are close to humans for different systems such as the immune system, and from the sound of this article, neurologically they are similar too. I agree that there should be a follow up study done on how the mice are effected the earlier they are exposed to the pesticide. I wonder if they could use CRISPR to help get rid of the genetic portion of the disease and then see if that could help cut down on the prevalence of the disease even when exposed to the pesticide.
ReplyDeleteBeing a medical scribe in the ER, I learn a lot about different diseases and disorders such as Parkinson's. It can be very sad to see a patient with advanced Parkinson's and they are no longer able to care for themselves. Parkinson's can cause someone to have tremors as well have difficulty ambulating. It very interesting to think that pesticides used on crops could be the reason that we have so many cases and diagnoses for Parkinson's.
ReplyDelete