Bright light exposure reduces TH-positive dopamine neurons in rats
 

Romeo et al. report [1]:
"The rats exposed to bright light for 20 days or 90 days showed a relatively greater number of neuromelanin-positive neurons. Surprisingly, TH-positive neurons decreased progressively in the substantia nigra reaching a significant 29% reduction after 90 days of continuous bright light exposure. This decrease was paralleled by a diminution of dopamine and its metabolite in the striatum. Remarkably, in preliminary analysis that accounted for population density, the age and race adjusted Parkinson's disease prevalence significantly correlated with average satellite-observed sky light pollution."
Reference

The epidemiology is a spatial correlation between light pollution and Parkinson's prevalence in the US, the Willis paper: a technique seen here before.

Clearly, if there is a causal relationship between light and PD, there are implications for sleep and the use of computers etc..

Perhaps, and this is just my speculation, this helps to explain the increase of PD over time as we follow natural light patterns less and less.

It doesn't explain the high prevalence of PD in the Amish communitity (see Rick's thread).

Reference

[1] "Bright light exposure reduces TH-positive dopamine neurons: implications of light pollution in Parkinson's disease epidemiology"
Stefania Romeo,Cristina Viaggi,Daniela Di Camillo,Allison W. Willis,Luca Lozzi,Cristina Rocchi,Marta Capannolo,Gabriella Aloisi,Francesca Vaglini,Rita Maccarone,Matteo Caleo,Cristina Missale,Brad A. Racette,Giovanni U. Corsini,Roberto Maggio
Nature, March 2013
http://www.nature.com/srep/2013/1303...srep01395.html

John

Omg
 

and so we wanted Parkinson's research to try something new. This is one of the most fall-off-your-chair research papers I have ever seen. Read the whole thing; I skip over some of the heavier science stuff because it lacks narrative and I don't know much about science, but in every paragraph where they are explaining things, there are sentences that jump out at you. Things I would never imagined. The lighting? OMG.
That's not just thinking outside the box, that's thinking right off the planet. That kind of creativity in science is a marvel to behold. Let's keep track of these people and make sure they get a fair hearing in the PD research world.

submariners spend months under 100% artificial light, do they have a higher incidence of pd? what about those living in the far north with months of darkness and also under 100% artificial light?
wonder what inspired these researchers to open this can of worms.

i have always assumed pd distribution in the u.s is somewhat removed from the causitive factors since numbers often taken from medicare statistics and as people age they often move to the city and/or warmer climates.

excellent can of worms
 

…Although light with longer wavelengths penetrates into the brain more effectively, shorter wavelength light can also penetrate into deep brain structures and regulate, for example, the seasonal cycle of reproduction in birds..,. Penetration of light into the brain has also been demonstrated in larger animals, including sheep and dog…

…light penetrating into the substantia nigra could be the source of oxidative stress. Light could oxidise dopamine and, in turn, induce the formation of neuromelanin, and cause dopamine neuron degeneration...

….animals continuously exposed to bright light for 3 months showed a significant decrease in dopamine (33%) and DOPAC (44%) ….

….the effect of light on dopamine neuron is strictly dependent on the wavelength used and the time of exposure….

…whether the reduction in TH-positive neurons produced by continuous exposure to light was induced by a direct effect of light on the substantia nigra or whether it was indirectly produced by the stress caused by retina activation (i.e. the complete alteration of the circadian rhythm). Continuous bright light profoundly alters the circadian cycle of the animals and their hormonal homeostasis…

One would suspect that the amount of light that reaches the substantia nigra in the human brain—for the size of the head, the thickness of the skull and the deep brain localization of the substantia nigra—will be negligible. However, scientific data refutes that assumption…. a tiny amount of light can reach deep brain structures in human beings and this amount is proportional to the length of exposure and the brightness of the light source….

…these observations suggest that artificial light rather than sunlight could play a role in Parkinson's disease,….

the spectral characteristics of artificial light, especially fluorescent light, are completely different from sunlight, as the sunlight spectrum is continuous while fluorescent light spectrum is discontinuous and shows several peaks. Light frequencies of the sunlight spectrum could protect rather than damage the dopamine neurons…

…the concept of plurifocal illness in Parkinson's disease is absolutely questionable since it is linked to the diagnostic purity….

AND THE FINAL PAGE OF THE STUDY SAYS:
Competing financial interests
The authors declare no competing financial interests.
Corresponding author
Correspondence to:
• Roberto Maggio
This work is licensed under a Creative Commons Attribution-Non-Commercial-NoDerivs 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/

bob, were're all entitled to our opinions.

if research on rats could always be transferred 100% to humans we would have been "cured" and/or have stopped progression years ago. a lot of pd trials of something that worked in rats have failed in humans.

so i'm not going to take any study on rats too seriously. especially when you can't get a sun tan from a normal fluorescent bulb. and a tan is from producing melanin.

they can grow human dopamine neurons in a petri dish, derived from skin cells from someone with pd. they could test their theory on them but what if the artificial light did inhibit dopamine production, what would you do with that info? it's still a very unnatural situation.


http://en.wikipedia.org/wiki/Melanin

Difficult to understand
 

Oh dear, I found many double negatives in the presentation of this study and got lost. Would anyone have the energy to make a summary.

One thing that stood out to me- weren't the researchers definitively stating that near infrared light has the ability to protect dopamine neurons. If this is the case shouldn't we all be getting treatment with that. I have a FAR (not near) infrared sauna- what's the difference in wave length? This is something we all could be doing.

A few other thoughts I had.

When studying botany, way back in the day, I remember hearing that plants growth was correlated not so much the exposure length of the daylight hours but rather the number of hours of darkness it was exposed to.

Finally,

I developed cataracts very young -in my early 40's. Was that an protective
response of mt body to a harmful amount or type of light?

What an interesting article! Light penetrates the brain!!!??!!
:Head-Spin:

[QUOTE=soccertese;966220]bob, were're all entitled to our opinions. Quote.

yes, in your opinion it is questionable why these scientists opened a can of words. In my opinion, it is excellent, at least as far as cans of worms go.

Quote: if research on rats could always be transferred 100% to humans we would have been "cured" and/or have stopped progression years ago... a lot of pd trials of something that worked in rats have failed in humans....
so i'm not going to take any study on rats too seriously.... quote

It is true that if we were mice, we would have been cured of everything by now. But they can't try anything on humans without trying it mice and rats; then primates, then us

they can grow human dopamine neurons in a petri dish,
and expose the petri dish to constant light for 90 days?

quote: what if the artificial light did inhibit dopamine production, what would you do with that info?quote

As they say in the study, lighting could be changed. I personally attended a sales pitch made to real estate developers from some company in California that was marketing flourescent tubes that they claimed matched the spectrum of sunlight, and they claimed that it was healthier. That was in the late 1980's. They went bankrupt because they were more expensive, and so the real estate companies did not buy them

This study may go nowhere. But it is one of the few that is not just repeating all the others.

Thank you for researching our illness, Dr. Maggio et al
 

Dear Roberto Maggio,

Your study of light and Parkinson's is one of the most exciting studies I have heard in years.

A discussion is taking place here: http://neurotalk.psychcentral.com/thread185478.html

(We all have Parkinson's) (Some are "citizen scientists"). The forum is influential in the Parkinson's community.

Please drop by and have a look. And it would be awesome if you or one or more of your colleagues would join our Neurotalk, answer questions, inform; discuss; take down the walls that exist in the Parkinson's world.

Roberto Maggio <roberto.maggio@univaq.it>

Dear Bob,
thank you for the E-mail.
I will be pleased to register in the forum.
Best regards
Roberto Maggio

I was unaware of it until I came across the paper on which this thread is based that there was a large literature linking exposure to artificial light to health problems. To supplement the paper, let's look at two of these that point indirectly at Parkinson's.

Parkinson's associated with melanoma. [1]
Melanoma associated with artificial light. [2]
Parkinson's associated with prostate cancer. [1]
Prostate cancer associated with artificial light. [3]
References

[1] "Study Examines Association Between Parkinson Disease, Cancer"
Sep 3, 2012
http://www.sciencedaily.com/releases...0903221130.htm

[2] "Are some melanomas caused by artificial light?"
Are some melanomas caused by artificial light?
Marina Kvaskoff, Philip Weinstein
http://www.ncbi.nlm.nih.gov/pubmed/20347530

[3] "Light linked to prostate cancer "
Feb 3, 2009
http://www.upi.com/Health_News/2009/...4881233680656/

John

How light impacts our brain
 

Very interesting.

I do know that fluorescent lights can trigger migraine headaches. Also, all the exposure to light from electronic screens makes one wonder what harm is being done to our brains. And good sleep hygiene (and we all know how important sleep is) requires total darkness, with limited exposure to bright lights prior to retiring.

A recent paper by Willis et al. [1] casts doubts on the conclusions drawn by Romeo et al. (see Post 1 of this thread.)

Willis et al. write:
"Critical analysis of recent research suggesting that light pollution causes Parkinson's disease (PD) reveals that such a hypothesis is unsustainable in the context of therapeutic use of light in treating various neuropsychiatric conditions. Reinterpretation of their findings suggests that retinal damage caused by prolonged light exposure may have contributed to the observed enhancement of experimental PD."

Reference

[1] "Parkinson's Disease, Lights and Melanocytes: Looking Beyond the Retina"
Gregory L. Willis, Cleo Moore & Stuart Maxwell Armstrong
Nature Scientific Reports, January 2014
http://www.nature.com/srep/2014/1401...srep03921.html

John

I hope you will be amused by my story !!
 

In May 2013, I was making eye test in order change my glasses when it was suggested to me that I would make a routine eye test. I agreed reluctantly as I had no complain from my eyes. This test lead to more tests which "confirmed" that I had uveal malonoma in my right eye and radiation treatment (eye plaque brachytherapy) was scheduled to take place on 22 July at a hospital in Edmonton which is at few hours drive from where I reside. We made all the elaborate preparations for the treatment including two days trip to Edmonten to do tests required by the hospital. But as fate wished, we were told that the treatment had to be cancelled because the surgeon who was to perform the therapy had an accident and he needs about two months to recoverer. Subsequently, we were told that the treatment should be done in Toronto and all arrangements and costs would be covered. However, I did not like the idea. My primary eye oncologist was a very likeable man in his late forties and as he noticed my reluctance, he told me that the tumor has not changed in size since first diagnosis about three months earlier and if I was ready to take the chance to wait other three months to repeat the test to check if the tumor is active or dormant. Since that time I have done tests every 3 months which indicated that my eye malonoma is dormant and may have been there many years earlier doing no harm.
My wife tells me every thing happens for a reason not understood by us and it is futile to put your faith only in logic and science!

The team that wrote the paper mentioned in Post 1 of this thread have written a follow-up paper. They hypothesize a link between light and occupation and PD [1].

"... even though the global intensity of light emitted by a computer display is relatively low compared to a fluorescent lamp, we observed that the light emitted at 706 nm by a CRT monitor was nearly one-third of the light emitted by a fluorescent lamp. Given that the average person may work or look at a computer display for hours on a daily basis, it is possible that some light could reach the substantia nigra. As a matter of fact, computer programmers tend to be diagnosed with Parkinson’s disease at a younger age compared to other patients, and risk of diagnosis in patient 50 years old or younger is greater in computer programmers".

Reference

[1] The Scientific World Journal, 2014
"Eyes as Gateways for Environmental Light to the Substantia Nigra: Relevance in Parkinson’s Disease"
Stefania Romeo,1 Daniela Di Camillo,2 Alessandra Splendiani,1 Marta Capannolo,1 Cristina Rocchi,1 Gabriella Aloisi,1 Irene Fasciani,1 Giovanni U. Corsini,3 Eugenio Scarnati,1 Luca Lozzi,2 and Roberto Maggio1
http://www.hindawi.com/journals/tswj/2014/317879/

John

This thread started in 2013 and it was updated in 2014. I'd like to bounce it up. Does anyone know whether research in this area continues?

To set the scene:

Romeo et al. wrote [1]:

"In the human subject analysed, this passage between the eye surface and the substantia nigra ... was 79.78 mm long ... . Within this length, 22.66 mm was comprised of the light transparent tissues of the eye (lens and vitreous humour) and 23.35 mm of liquid behind the superior orbital fissure inside the skull ... . ... [P]art of the remaining path could be inside the CSF around the optic nerve (9.73 mm). Taken together, the light transparent portion of this path could be as long as 55.74 mm, meaning that at some angle, only 24.04 mm of biological tissue stands between the external light environment and the substantia nigra in this patient."

and:

"[W]e have recently shown that continuous (three months) bright light exposure of rats induces formation of neuromelanin and reduces tyrosine hydroxylase positive neurons in the substantia nigra".

Wikipedia states [2]:

"Tyrosine hydroxylase or tyrosine 3-monooxygenase is the enzyme responsible for catalyzing the conversion of the amino acid L-tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA)."

PwP partially avoid this constraint because of the drugs that we take provide levodopa. But, many of us will be still producing endogenous levodopa and will need the TH for this.

I can (13 years post-diagnosis) still go overnight without drugs, and several hours in the morning before I need to take them. I've always thought of this being due to having reserves of levodopa, which build up during the night.

As a final point, if light does prove to reach the SN, it would suggest that wearing sunglasses, perhaps with lenses chosen to stop harmful frequencies of light, might be a partial therapy for PD.

References:

[1] "Eyes as Gateways for Environmental Light to the Substantia Nigra: Relevance in Parkinson's Disease"
Stefania Romeo, 1 Daniela Di Camillo, 2 Alessandra Splendiani, 1 Marta Capannolo, 1 Cristina Rocchi, 1 Gabriella Aloisi, 1 Irene Fasciani, 1 Giovanni U. Corsini, 3 Eugenio Scarnati, 1 Luca Lozzi, 2 and Roberto Maggio
ScientificWorldJournal 2014
Eyes as Gateways for Environmental Light to the Substantia Nigra: Relevance in Parkinson's Disease

[2] Wikipedia
Tyrosine hydroxylase - Wikipedia

John