3 ms·

Eye test may detect Parkinson’s before symptoms appear

66 points by renafowler 10y ago

dannylandau 10y ago
I can't tell if this report is vapor research or there is something of merit. For example, if only tested on mice, then how is this related to Parkinson's Disease, can anyone clarify?
- nickledave 10y ago
  The results in the research article were obtained with a rat model of Parkinson's, where Parkinsonian symptoms are induced with rotenone. Most models of Parkinson's are based on neurotoxic drugs (e.g. MPTP, first discovered to induce Parkinsonian symptoms in heroin addicts) so they're kind of the best we can do. (there's also genetic models--e.g. mice that express chronically low levels of dopamine. But basically other animals don't get Parkinson's in the wild as far as we can tell.) There's a summary of the evidence for the rotenone model in the discussion of the paper itself, and the paper is in an open access journal so you can read it should you so desire: http://actaneurocomms.biomedcentral.com/articles/10.1186/s40478-016-0346-z http://actaneurocomms.biomedcentral.com/articles/10.1186/s40... There is something of merit here if there's any reason to believe that actual Parkinson's patients show similar retinal degeneration far before they show any other symptoms. The authors don't mention any evidence for that...so I'm guessing there's not any. Either they are wildly scrambling to find some, or a cynic might suggest they looked already in humans and didn't find any, so they published this instead. A paper showing multiple lines of evidence supporting their theory in a rodent model and in a patient population would probably have been a home run that got them into a glam mag.
feld 10y ago
I wonder if this is muscle twitching similar to the claim of detection just by voice over the phone
coetzeesg 10y ago
There is some evidence that the brain (and substantia nigra) is not the only region where risk for Parkinson's can accumulate. There may be some ties to developmental processes, lymphocytes, and the liver and fat cells[0]. [0]http://www.nature.com/articles/srep30509 http://www.nature.com/articles/srep30509 [0]http://parkinsonsnewstoday.com/2016/08/11/parkinsons-risk-mutations-impact-brain-least-of-all/ http://parkinsonsnewstoday.com/2016/08/11/parkinsons-risk-mu...
- nickledave 10y ago
  Hmm. In your studies can you identify retinal tissue? Guessing not since it's such a relatively small amount and might not have a clear marker like adipose/liver tissue. Accumulating mutations could cause Parkinson's--some sort of inflammatory syndrome from altered metabolic pathways, you can probably explain it better than me--but the study in OP seems to be suggesting retinal degeneration is a symptom, right? Maybe retinal tissue could be a "canary in the coal mine" because it's more sensitive to these changes in metabolism? I'd be interested to know what you think.
  - coetzeesg 10y ago
    Yea, I can only work with tissues that I have chromatin marks for, and retinal tissue is not one that is easily available. But it's possible that the retinal features are an early detector of disregulation (in some pathway to Parkinson’s), and it would be interesting to see precisely what it’s detecting, perhaps shedding more light on inherited risk.
    - nickledave 10y ago
      Ah, it's chromatin marks you need. Well I guess you could get a lot of retinal tissue from the rat model they use and try to find some. Interesting that this finding is in an animal that doesn't depend as much on vision as we do. Might be worth determining if the result holds up in e.g. a macaque model.

66 points by renafowler 10y ago

I can't tell if this report is vapor research or there is something of merit. For example, if only tested on mice, then how is this related to Parkinson's Disease, can anyone clarify?

nickledave 10y ago
The results in the research article were obtained with a rat model of Parkinson's, where Parkinsonian symptoms are induced with rotenone. Most models of Parkinson's are based on neurotoxic drugs (e.g. MPTP, first discovered to induce Parkinsonian symptoms in heroin addicts) so they're kind of the best we can do. (there's also genetic models--e.g. mice that express chronically low levels of dopamine. But basically other animals don't get Parkinson's in the wild as far as we can tell.) There's a summary of the evidence for the rotenone model in the discussion of the paper itself, and the paper is in an open access journal so you can read it should you so desire: http://actaneurocomms.biomedcentral.com/articles/10.1186/s40478-016-0346-z http://actaneurocomms.biomedcentral.com/articles/10.1186/s40... There is something of merit here if there's any reason to believe that actual Parkinson's patients show similar retinal degeneration far before they show any other symptoms. The authors don't mention any evidence for that...so I'm guessing there's not any. Either they are wildly scrambling to find some, or a cynic might suggest they looked already in humans and didn't find any, so they published this instead. A paper showing multiple lines of evidence supporting their theory in a rodent model and in a patient population would probably have been a home run that got them into a glam mag.

feld 10y ago

I wonder if this is muscle twitching similar to the claim of detection just by voice over the phone

coetzeesg 10y ago

There is some evidence that the brain (and substantia nigra) is not the only region where risk for Parkinson's can accumulate. There may be some ties to developmental processes, lymphocytes, and the liver and fat cells[0]. [0]http://www.nature.com/articles/srep30509 http://www.nature.com/articles/srep30509 [0]http://parkinsonsnewstoday.com/2016/08/11/parkinsons-risk-mutations-impact-brain-least-of-all/ http://parkinsonsnewstoday.com/2016/08/11/parkinsons-risk-mu...

nickledave 10y ago
Hmm. In your studies can you identify retinal tissue? Guessing not since it's such a relatively small amount and might not have a clear marker like adipose/liver tissue. Accumulating mutations could cause Parkinson's--some sort of inflammatory syndrome from altered metabolic pathways, you can probably explain it better than me--but the study in OP seems to be suggesting retinal degeneration is a symptom, right? Maybe retinal tissue could be a "canary in the coal mine" because it's more sensitive to these changes in metabolism? I'd be interested to know what you think.
- coetzeesg 10y ago
  Yea, I can only work with tissues that I have chromatin marks for, and retinal tissue is not one that is easily available. But it's possible that the retinal features are an early detector of disregulation (in some pathway to Parkinson’s), and it would be interesting to see precisely what it’s detecting, perhaps shedding more light on inherited risk.
  - nickledave 10y ago
    Ah, it's chromatin marks you need. Well I guess you could get a lot of retinal tissue from the rat model they use and try to find some. Interesting that this finding is in an animal that doesn't depend as much on vision as we do. Might be worth determining if the result holds up in e.g. a macaque model.