Tag: Substantia nigra

The heights of Parkinson’s

~ Simon ~ 1 Comment

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Being tall is considered desirable in many cultures.

Recent research suggests that height may be associated with an increased risk of developing Parkinson’s.

In today’s post, we will review this new research and try to understand what it could mean.

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Wadlow (back row on the left). Source: Telegraph

Robert Pershing Wadlow was always in the back row of school photos.

Born February 22nd 1918, Wadlow’s birth certificate indicated that he was “normal height and weight“, but from that point onwards, there was nothing normal about his rate of growth.

By the time, Robert was 8 years old, he was taller than his father (he was 6 foot/183cm). And eight years later when he turned 16, Robert was 8 foot 1 (2.47 m)… and he was still growing.

Here is a picture of him with his family at 19 years of age:

Source: Businessinsider

Robert was the tallest person in recorded history, and at the time of his death – at the tragically young age of 22 – Robert was almost 9 feet tall (8 ft 11; 2.72 m)… and still growing! (due to hyperplasia)

While not quite reaching the same lofty heights as Robert, I can sort of relate to his situation. You see, in addition to being freakishly good looking, I’m also on the tall side side of things.

On a good day, I am 6 foot 8 (207cm), but often 6 foot 7 around bed time (gravity is a drag!).

Whoa, that’s tall. But what does any of this have to do with Parkinson’s?

Continue reading “The heights of Parkinson’s” →

Mind blowing modulation of mind

~ Simon ~ 2 Comments

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Neuromodulation of specific circuits in the brain represents a means of adjusting deficits in neural performance and significantly improving quality of life.

Deep brain stimulation has been widely applied to the treatment of Parkinson’s since Alim Benabid first discovered that electrical stimulation of the basal ganglia improves the symptoms of the condition in the late 1980s.

Now researchers are attempting to refine the approach further with new technology (such as optogenetics) and more specific targeting – stimulating only particular types of neurons – with impressive results and potentially immediate implications for treatment.

In today’s post, we will discuss what optogenetics is, review some new preclinical results, and explore those potentially immediate implications for the treatment of Parkinson’s.

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Vienna. Source: Worldofcruising

In 2016, I was lucky enough to be at the “Dopamine” research conference in Vienna (Austria).

It is a wonderful city, the late summer weather was perfect, and an amazing collection of brilliant researchers had gathered to focus on all things dopamine-related for four days. The conference highlighted all the exciting new research being done on this chemical.

Source: Medium

There was – of course – a lots of research being presented on Parkinson’s disease as well, given that dopamine plays such a fundamental role in the condition.

And I was sitting in the lecture presentations, listening to all these new results being discussed, thinking how fantastic it all was, when a researcher from Carnegie Mellon University stood up and (without exaggeration) completely – blew – my – mind!

Basically sums my reaction. Source: Canacopegdl

Seriously. I was left speechless by the results presented.

Wow, what were the results???

Continue reading “Mind blowing modulation of mind” →

What is GDNF without RET?

~ Simon ~ 2 Comments

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Neurotrophic factors – like Glial cell line-derived neurotrophic factor (or GDNF) – hold great hope for regenerative therapy in Parkinson’s research. New research, however, indicates that simply injecting the protein into the brain may not be enough.

Scientists at Rush University Medical Center (in Chicago) conducted a postmortem analysis of brains from people who passed away with Parkinson’s and made an intriguing discovery.

They found that many of the remaining dopamine neurons appear to not be producing a protein called Ret, which is required for GDNF signaling. In addition, other components of GDNF signaling pathway were missing. 

In today’s post, we will review the background of this new study, outline what the study found, and discuss the implications of the research.

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GDNF. Source: Wikipedia

Glial cell line-derived neurotrophic factor (or GDNF) is a topic that gets a lot of reader attention on the SoPD. It is a tiny protein that holds great hope for the Parkinson’s community in terms of providing a potential neuroprotective and regenerative therapy.

GDNF is a type of neurotrophic factor, which are small naturally-occurring proteins that nurture neurons and support their growth. There are different kinds of neurotrophic factors, and the testing of some of them in preclinical models of Parkinson’s has generated encouraging results (particularly in the case of GDNF – click here to read a previous SoPD post on this topic).

But the translation of those initial results in cell culture and animal models of Parkinson’s has been difficult in clinical trials of neurotrophic factors.

This has led to many questions being asked within the research community about the nature of biological signaling pathways involved with neurotrophic factors and whether they might be affected in Parkinson’s.

The majority of the neurotrophic factors that have been tested in models of Parkinson’s and in clinical trials for Parkinson’s belong to a branch that requires the RET signaling pathway to be available to have their neuroprotective effect.

What is the RET signaling pathway?

Continue reading “What is GDNF without RET?” →

T-cells: First responders

~ Simon ~ 5 Comments

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The cause of the cell loss and pathology associated with Parkinson’s is still unknown. While the later stages of the condition have been well investigated based on various pathological marker (ie Braak staging), the early manifestations of the condition are still a mystery.

Cells of the immune system are early responders to any signs of trouble in our bodies, and recently researchers have been looking at a specific class of immune cells (called T cells) in postmortem sections of brains from people who passed away with Parkinson’s.

Curiously, in their analysis the researchers found that the bulk of activity of T cells occurs before any cell loss or pathology appears.

In today’s post, we will discuss what T cells are, review the new research, and explore what this could mean for potential therapies for Parkinson’s.

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Your hematopoietic system. Source: Wikipedia

The process of hematopoiesis (or blood formation) is absolutely fascinating.

Seriously.

You start off with a single, multi-potential hematopoietic stem cell. This is called a hemocytoblast (it’s the big cell in middle of the image below):

A hemocytoblast. Source: Pinterest

Given enough time, this single cell will give rise to an entire blood system, made up of many of different types of cells with very specific functions that are required for us to live normal lives.

It is a remarkable achievement of biology.

Understand that at any moment in time your blood system will contain 20-30 trillion cells (in the average human body). And as the image near the top of the post suggests, there are quite a few branches of potential cell types that these blood stem cells can generate.

Very interesting, but what does this have to do with Parkinson’s?

Continue reading “T-cells: First responders” →

A Lewy body condition?

~ Simon ~ 7 Comments

 

Lewy bodies are densely packed, circular clusters of protein that have traditionally been considered a characteristic feature of the Parkinsonian brain. Recently, however, evidence has been accumulating which calls into question this ‘defining feature’ of the condition.

The presence Lewy bodies in some cases of other neurological conditions (such as Alzheimer’s), and their complete absence in some cases of Parkinson’s, are leading many researchers to question their pivotal role in PD.

In today’s post, we will look at a new research report of Parkinson’s post mortem cases studies which present no Lewy bodies, and we will disucss what this might mean for our understanding of Parkinson’s and the future treatment of the condition.

 

Neuropathologists conducting a gross examination of a brain. Source: NBC

At present, a definitive diagnosis of Parkinson’s can only be made at the postmortem stage with an examination of the brain. Until that moment, all cases of Parkinson’s are ‘suspected’. When a neuropathologist makes an examination of the brain of a person who passed away with the clinical features of Parkinson’s, there are two characteristic hallmarks that they will be looking for in order to provide a final diagnosis of the condition:

1.  The loss of specific populations of cells in the brain, such as the dopamine producing neurons in a region called the substantia nigra, which lies in an area called the midbrain (at the base of the brain/top of the brain stem). As the name suggests, the substantia nigra region is visible due to the production of a ‘substance dark’ molecule called neuromelanin in the dopamine neurons. And as you can see in the image below, the Parkinsonian brain has less dark pigmented cells in the substantia nigra region of the midbrain.

The dark pigmented dopamine neurons in the substantia nigra are reduced in the Parkinsonian brain (right). Source:Memorangapp

2.  Dense, circular clusters (or aggregates) of protein within cells, which are called Lewy bodies.

shutterstock_227273575A cartoon of a neuron, with the Lewy body indicated within the cell body. Source: Alzheimer’s news

A Lewy body is referred to as a cellular inclusion, as they are almost always found inside the cell body. They generally measure between 5–25 microns in diameter (5 microns is 0.005 mm) and thus they are tiny. But when compared to the neuron within which they reside they are rather large (neurons usually measures 40-100 microns in diameter).

A photo of a Lewy body inside of a neuron. Source: Neuropathology-web

Do all Parkinson’s brains have Lewy bodies?

This is a really interesting question. Welcome to the topic of this post.

Continue reading “A Lewy body condition?” →

Voyager Therapeutics: Phase I clinical trial update

~ Simon ~ 12 Comments

Today biotech company Voyager Therapeutics announced an update on their ongoing phase Ib clinical trial. The trial is evaluating the safety and tolerance of a gene therapy approach for people with advanced Parkinson’s.

Gene therapy is a technique that involves inserting new DNA into a cell using viruses. In this clinical trial, the virally delivered DNA helps the infected cell to produce dopamine in order to alleviate the motor features of Parkinson’s.

In today’s post we will discuss what gene therapy is, review the new results mentioned in the update, and look at other gene therapy approaches for Parkinson’s.


Source: Baltimoresun

Voyager Therapeutics is a clinical-stage gene therapy company that is focused on treatments for neurological conditions, such as Parkinson’s. Today the company announced an update of their ongoing Phase 1b trial of their product VY-AADC01 (Click here to see the press release).

VY-AADC01 represents a new class of treatment for Parkinson’s, as it is a form of gene therapy.

What is gene therapy?

The gene therapy involves introducing a piece of DNA into a cell which will cause the cell to produce proteins that they usually do not (either by nature or by mutation). The DNA is artificially inserted into cells and the cell’s protein producing machinery does the rest.

Source: Yourgenome

How does gene therapy work?

Continue reading “Voyager Therapeutics: Phase I clinical trial update” →

Mickey becomes more human?

~ Simon ~ 12 Comments

For a long time researchers have lacked truly disease-relevant models of Parkinson’s.

We have loaded cells with toxins to cause cell death, we have loaded cells with mutant proteins to cause cell death, we have loaded cells with… well, you get the idea. Long story short though, we have never had proper models of Parkinson’s – that is a model which present all of the cardinal features of the condition (Lewy bodies, cell loss, and motor impairment).

The various models we have available have provided us with a wealth of knowledge about the biology of how cells die and how we can protect them, which has led to numerous experimental drugs being tested in the clinic. But there has always been a linger question of ‘how disease-relevant are these models?’

This situation may be about to change.

In today’s post we will look at new research in which Japanese researchers have genetically engineered mice in which they observed the generation of Lewy bodies, the loss of dopamine neurons and motor impairments. We will look at how these mice have been generated, and what it may tell us about Parkinson’s.

Walt Disney. Source: PBS

Ok, before we start today’s post: Five interesting facts about the animator Walt Disney (1901 – 1966):

  • Disney dropped out of high school at age 16 with the goal of joining the Army to help out in the war effort. He was rejected for being underage, but was able to get a job as an ambulance driver with the Red Cross in France.
  • From 1928 (the birth of Mickey Mouse) until 1947, Disney himself performed the voice of Mickey.
  • Mickey Mouse was originally named “Mortimer Mouse”, but it was Disney’s wife who suggested that the name Mortimer sounded too pompous (seriously, can you imagine a world with the “Mortimer Mouse show”?). She convinced Disney to change the name to Mickey (the name Mortimer was later given to one of Mickey’s rivals).
  • To this day, Disney holds the record for the most individual Academy Awards and nominations. Between 1932 and 1969, he won 22 Academy Awards and was nominated 59 times (Source).
  • And best of all: On his deathbed as he lay dying from lung cancer, Disney wrote the name “Kurt Russell” on a piece of paper. They were in effect his ‘last words’. But no one knows what they mean. Even Kurt is a bit perplexed by it all. He (along with many others) was a child actor contracted to the Disney company at the time, but why did Walt write Russell’s name as opposed to something more deep and meaningful (no disrespect intended towards Mr Russell).

Actor Kurt Russell. Source: Fxguide

When asked why he thought his great creation “Mickey mouse” was so popular, Walt Disney responded that “When people laugh at Mickey Mouse, it’s because he’s so human; and that is the secret of his popularity”.

Mickey Mouse. Source: Ohmy.Disney

This is a curious statement.

Curious because in biomedical research, mice are used in experiments to better understand the molecular pathways underlying basic biology and for the testing of novel therapeutics, and yet they are so NOT human.

There are major biological differences between us and them.

Not human. Source: USNews

It has been a major dilemma for the research community for some time with regards to translating novel therapies to humans, and it raises obvious ethical questions of whether we should be using mice at all for the basic research if they are so different from us. This problem is particularly apparent in the field of immunology, where the differences between ‘mice and men’ is so vast in some cases that researcher have called for moving away from mice entirely and focusing on solely human models (Click here and here for a good reads on this topic).

What does this have to do with Parkinson’s?

Continue reading “Mickey becomes more human?” →

When the zombies are all in your head

~ Simon ~ 5 Comments

In your brain there are different types of cells.

Firstly there are the neurons (the prima donnas that we believe do most of the communication of information). Next there are the microglia cells, which act as the first and main line of active immune defence in the brain. There are also oligodendrocyte, that wrap protective sheets around the branches of the neurons and help them to pass signals.

And then there are astrocytes.

These are the ‘helper cells’ which maintain a comfortable environment for the neurons and aid them in their task. Recently, researchers in California reported an curious observation in the Parkinsonian brain: some astrocytes have entered an altered ‘zombie’-like state. And this might not be such a good thing.

In today’s post, we’ll review the research and discuss what it could mean – if independently replicated – for the Parkinson’s community.

Zombies. Source: wallpapersbrowse

I don’t understand the current fascination with zombies.

There are books, movies, television shows, video games. All dealing with the popular idea of dead bodies wandering the Earth terrifying people. But why the fascination? Why does this idea have such appeal to a wide portion of the populous?

I just don’t get it.

Even more of a mystery, however, is where the modern idea of the ‘zombie’ actually came from originally.

You see, no one really knows.

Huh? What do you mean?

Some people believe that the word ‘zombie’ is derived from West African languages – ndzumbi means ‘corpse’ in the Mitsogo language of Gabon, and nzambi means the ‘spirit of a dead person’ in the Kongo language. But how did a word from the African continent become embedded in our psyche?

Others associate the idea of a zombie with Haitian slaves in the 1700s who believed that dying would let them return back to lan guinée (African Guinea) in a kind of afterlife. But apparently that freedom did not apply to situations of suicide. Rather, those who took their own life would be condemned to walk the Hispaniola plantations for eternity as an undead slave. Perhaps this was the starting point for the ‘zombie’.

More recently the word ‘zonbi’ (not a typo) appeared in the Louisiana Creole and the Haitian Creole and represented a person who is killed and was then brought to life without speech or free will.

Delightful stuff for the start of a post on Parkinson’s research, huh?

But we’re going somewhere with this.

Continue reading “When the zombies are all in your head” →

Are Lewy bodies fake news?

~ Simon ~ 21 Comments

One of the cardinal features of the Parkinsonian brain are dense, circular clusters of protein that we call ‘Lewy bodies’. 

But what exactly are these Lewy bodies?

How do they form?

And what function do they serve?

More importantly: Are they part of the problem – helping to cause of Parkinson’s? Or are they a desperate attempt by a sick cell to save itself?

In today’s post, we will have a look at new research that makes a very close inspection of Lewy bodies and finds some interesting new details that might tell us something about Parkinson’s.

Neuropathologists conducting a gross examination of a brain. Source: NBC

A definitive diagnosis of Parkinson’s disease can only be made at the postmortem stage with an examination of the brain. Until that moment, all cases of Parkinson’s disease are ‘suspected’.

When a neuropathologist makes an examination of the brain of a person who passed away with the clinical features of Parkinson’s, there are two characteristic hallmarks that they will be looking for in order to provide a final diagnosis of the condition:

1.  The loss of specific populations of cells in the brain, such as the dopamine producing neurons in a region called the substantia nigra, which lies in an area called the midbrain (at the base of the brain/top of the brain stem).

d1ea3d21c36935b85043b3b53f2edb1f87ab7fa6

The dark pigmented dopamine neurons in the substantia nigra are reduced in the Parkinson’s disease brain (right). Source:Memorangapp

2.  Dense, circular clusters (or aggregates) of protein within cells, which are called Lewy bodies.

shutterstock_227273575

A cartoon of a neuron, with the Lewy body indicated within the cell body. Source: Alzheimer’s news

What is a Lewy body?

A Lewy body is referred to as a cellular inclusion (that is, ‘a thing that is included within a whole’), as they are almost always found inside the cell body. They generally measure between 5–25 microns in diameter (5 microns is 0.005 mm) thus they are tiny, but when compared to the neuron within which they reside they are rather large (neurons usually measures 40-100 microns in diameter).

A photo of a Lewy body inside of a neuron. Source: Neuropathology-web

How do Lewy bodies form? And what is their function?

The short answer to these questions is:

Source: Wellbeing365

The longer answer is: Our understanding of how Lewy bodies are formed – and their actual role in neurodegenerative conditions like Parkinson’s – is extremely limited. No one has ever observed one forming. Lewy bodies are very difficult to generate in the lab under experimental conditions. And as for their function, this is the source of much guess work and serious debate (we’ll come back to this topic later in this post).

Ok, but what are Lewy bodies actually made of?

Continue reading “Are Lewy bodies fake news?” →

“Three hellos” for Parkinson’s

~ Simon ~ 14 Comments

Trehalose is a small molecule – nutritionally equivalent to glucose – that helps to prevent protein from aggregating (that is, clustering together in a bad way).

Parkinson’s disease is a neurodegenerative condition that is characterised by protein aggregating, or clustering together in a bad way.

Is anyone else thinking what I’m thinking?

In today’s post we will look at what trelahose is, review some of the research has been done in the context of Parkinson’s disease, and discuss how we should be thinking about assessing this molecule clinically.

Neuropathologists examining a section of brain tissue. Source: Imperial

When a neuropathologist makes an examination of the brain of a person who passed away with Parkinson’s, there are two characteristic hallmarks that they will be looking for in order to provide a definitively postmortem diagnosis of the condition:

1.  The loss of dopamine producing neurons in a region of the brain called the substantia nigra.

d1ea3d21c36935b85043b3b53f2edb1f87ab7fa6

The dark pigmented dopamine neurons in the substantia nigra are reduced in the Parkinson’s disease brain (right). Source:Memorangapp

2.  The clustering (or ‘aggregation’) of a protein called alpha synuclein. Specifically, they will be looking for dense circular aggregates of the protein within cells, which are referred to as Lewy bodies.

A Lewy body inside of a neuron. Source: Neuropathology-web

Alpha-synuclein is actually a very common protein in the brain – it makes up about 1% of the material in neurons (and understand that there are thousands of different proteins in a cell, thus 1% is a huge portion). For some reason, however, in Parkinson’s disease this protein starts to aggregate and ultimately forms into Lewy bodies:

shutterstock_227273575

A cartoon of a neuron, with the Lewy body indicated within the cell body. Source: Alzheimer’s news

In addition to Lewy bodies, the neuropathologist may also see alpha synuclein clustering in other parts of affected cells. For example, aggregated alpha synuclein can be seen in the branches of cells (these clusterings are called ‘Lewy neurites‘ – see the image below where alpha synuclein has been stained brown on a section of brain from a person with Parkinson’s disease.

Lewy_neurites_alpha_synuclein

Examples of Lewy neurites (indicated by arrows). Source: Wikimedia

Given these two distinctive features of the Parkinsonian brain (the loss of dopamine neurons and the aggregation of alpha synuclein), a great deal of research has focused on A.) neuroprotective agents to protect the remaining dopamine-producing neurons in the substantia nigra, and B.) compounds that stop the aggregation of alpha synuclein.

In today’s post, we will look at the research that has been conducted on one particular compounds that appears to stop the aggregation of alpha synuclein.

It is call Trehalose (pronounces ‘tray-hellos’).

Continue reading ““Three hellos” for Parkinson’s” →