I was recently perplexed with my first case of tuberous sclerosis complex (TSC). I had no idea what treatment, monitoring and surveillance I needed to institute. I quickly checked things up in neurochecklists; I found excellent checklists on the pathology and clinical features, but was disappointed that there were no treatment or monitoring checklists. I quickly hunted down TSC diagnostic criteriaand TSC surveillance recommendations and updated neurochecklists. Phew!
In the process I discovered that TSC features may improve on treatment with a class of drugs called mTOR inhibitors. Highfalutin stuff I said to myself, and thought nothing more of it. I had to reassess my opinion very shortly afterwards when I came across the Association of British Neurologists (ABN)SoundCloud page with ABN President Phil Smith interviewing Ingrid Scheffer on epilepsy genetics.
We have all experienced that disquieting feeling of just learning something new, and then seeing it crop up all over the place. This is what I felt when Ingrid Scheffer casually stated that Tuberous Sclerosis is an mTORopathy. mTOR is big enough to be an ‘opathy‘, and I was completely ignorant of it! And how come I haven’t heard of Ingrid Scheffer before now-serves me right for missing the last ABN conference in Brighton.
I decided to dig a bit deeper and here are 9 things about mTOR I discovered:
1
mTOR stands for mammalian (or mechanistic) target of rapamycin
The mTOR pathway is important in regulating cell growth and cell death
4
mTOR has an important role in many disorders (mTORopathies). These include tuberous sclerosis, epilepsy, autism, traumatic brain injury, brain tumours, and dementia
The DEPDC5 gene is mutated in many neurological disorders such as familial focal epilepsies, focal cortical dysplasia, and epileptic spasms. These constitute DEPDC5 motoropathies.
The brain is a mystery and that is why neurologists find it fascinating. The more we know, the more it tantalises us with its hidden gems. Great neurologists have waxed lyrical about the ability of the brain to elude all efforts to fully understand it. Santiago Ramon y Cajal for instance says:
“The brain is a world
consisting of a number of unexplored continents
and great stretches of unknown territory”
Non-neurologists are similarly awed by the brain. Emerson M. Pugh for example says:
“If the human brain were so simple that we could understand it,
we would be so simple that we couldn’t”
Neuroscience and neuroanatomy are at the forefront of exploring this great unknown; the research output from these fields is mind-boggling (pardon the intended pun). But which recent findings are most likely to change neurological practice in the near future? Here are my top 6.
The finding however raises hope of better treatments for some neurological diseases. Because the lymphatic system is closely linked to the immune system, multiple sclerosis (MS) is one potential beneficiary of this discovery. Because lymphatics also act as drainage systems, there are implications for conditions such as Alzheimer’s Disease (AD). Hopefully this brain lymphatic system could be manipulated to clear the accumulated abnormal proteins that cause AD and other neurodegenerative diseases.
The brain’s extensive connections is one of its enduring and fascinating mysteries. The winding fibers and tracts, meandering and looping around each other, demonstrate the brain’s complexity. As soon as we think we have grasped it all, along comes a discovery that causes a paradigm shift. This is illustrated by the report of the discovery of a new brain network involved in memory processing. This Parietal Memory Network (PMN), in the brain’s left hemisphere, responds differentially to new and to old information. This may have relevance for cognitive disorders such as Alzheimer’s Disease (AD). For the more technical details of the network, the paper is published in the journal Trends in Cognitive Neuroscience.
In a similar vein is the discovery of previously unknown brain fiber tractscalled the vertical occipital fasciculus (VOF). This new ‘brain corridor‘ is involved in visual processing. The research paper, published in the Proceedings of the National Academy of Science (PNAS), says the VOF is important in the perception of words and faces, amongst other things, and is ‘involved in the control of eye movements, attention, and motion perception‘. The main benefit of this finding is the improvement of our understanding of how the brain learns to read.
The common assumption that the electrical activity of the comatose brain flatlines on the electroencephalogram (EEG) now appears to be a misconception. This is according to a report of the discovery of a previously unknown electrical brain activity in deep comasuggests. One journal reported this as the discovery oflife after brain death!
These electrical waves, seen in deep coma, are called Nu complexes. They are well-described in the original paper in PLoS One. This finding will alter our definition of brain death which relies very much on the absence of organised brain electrical activity. Another implication is for patients whose medical conditions require that they are put into a coma; this finding will potentially guide the anaesthetist to apply the best form of induced coma.
5. Newly discovered brain cell type
I thought I learnt all the different types brain cells or neurones that exist when I was in medical school. The mysterious brain however has a joker at every corner. The report of the discovery of a new type of neuroneshould come as a surprise, but by now we have learnt not to be shocked by new brain discoveries. The strange thing about these cells, found in the hippocampus of the the brains of mice, is that they have direct connections between their axons (the single long tail) and their dendrites (the smaller hair like projections). This connection by-passes the nerve body; this direct connection enhances the strength of the signals the cell generates. The reason for this peculiarity is not clear but, because the hippocampus is the seat of memory, I guess there are implications for cognitive disorders.
6. Newly discovered brain repair enhancers
We know that the brain repairs itself (neuroplasticity), and that brain fibers make new connections even if this occurs very slowly. What is new is that these processes can be enhanced or accelerated by external agents. Two interesting substances recently reported are psilocybin and curry. Yes, healing mushrooms and spices!
It appears that Psilocybin (psychedelic mushrooms) can establish stable connections between parts of the brain which do not normally communicate well. The research on this is published under the title ‘Homological Scaffolds of Brain Functional Networks‘. The paper describes how psilocybin helps in nerve re-wiring with the potential implications for the treatment of depression and addiction. A bit paradoxical, using an addictive substance to treat addiction; but hey, this is the brain we are talking about!
Curry on the other hand contains tumeric which contains tumerone. Tumerone has now been shown to help with nerve growth repair, and it does this by causing proliferation of brain nerve cells. The research itself is titled ‘Aromatic-tumerone induces neural stem cell proliferation in vitro and in vivo‘. It is a study in rats, but are human brains very different? Potential beneficiaries are all the neurodegenerative diseases which neurologists have singularly failed to reverse.
Brain tumours are among the most distressing of cancers, partly because of they arise from the most important body organ. Current treatment revolves around debulking surgery and palliative chemotherapy and radiotherapy. There are developments every day to improve the outcome of this awful cancer, beyond the Below are 5 things that may, or may not, lead to better brain tumour care
The dreaded poliovirus, after all the years of trying to eradicate it, seems to have some benefit after all. The virus may come in handy in the fight against the worst type of brain tumour, glioblastoma multiforme. Matthias Gromeier is leading the research in this field. It however has a long way to go, and this analysis in Forbes puts the progress in perspective.
As you may imagine, it is achallenge for the neurosurgeon to tell cancer cells apart from normal tumour cells during surgery. This therefore often leads to incomplete removal of the cancerous cells. The development of a laser probe that could help distinguish normal from abnormal cells is therefore welcome. The laser distinguishes normal from abnormal cells by the way they reflect light back to it. You may learn more about this in the BBC titled Laser detects brain tumour cells during surgery.
The BBC link above is actually better than ‘good enough’ because it also makes reference to another innovation, the iknife or intelligent knife. This is ‘an electro-surgical scalpel that produces smoke as it cuts through tissue‘. The tissue is then quickly analysed to tell what type of tumour the surgeon is facing. The video clip above says it all.
Finally, this technique uses high temperatures to treat brain tumours. It is described as an ‘MRI-guided high-intensity laser probe that “cooks” cancer cells deep within the brain’. That says it all!
There are very few disabilities worse than paralysis from spinal cord injury. This often results from sudden catastrophes and frequently affects the young and active. It is very poignant that many incidents occur during recreational activities, and horse rising is one prominent example. Nothing exemplifies this more dramatically than the case of Christopher Reeve, famous for playing Superman.
The damage is typically catastrophic and this MRI scan shows how a fracture of the vertebrae could seriously damage the spinal cord, in this case it affects the neck. Spinal cord injuries often mean a life on a wheelchair or even worse, a bed-bound existence. Rehabilitation is often limited to maximizing potential.
There are however several scientific advances that will hopefully change the outlook for spinal cord injuries. Here are 6 rays of light at the end of the tunnel.
By delivering electrical impulses to the spinal cord, researchers have successfully got spinal cord injured subjects to make walking movements. The advantage of this procedure is that it is not invasive. It’s not yet walking, but its a step in the right direction.
The future is however more futuristic if trial of regrowing the spinal cord. Its mainly in zebrafish and rats for now, but there is at least a report of using nasal cells to repair the spinal cord in man.
Another potential method is head transplantation, which is essentially spinal cord reattachment. See my previous post on this titled Head transplant, anyone?
If you are keen on more academic take on this topic, an article in Nature titled Spinal cord repair strategies: why do they work? is just the thing for you, and it shows it’s not all doom and gloom.
It was the final day of the American Association of Neurology (ANA) conference yesterday and prion diseases took center stage. John Collinge, the only prominent British presence at the conference, set the ball rolling with insights into the potential treatment of CJD with anti-PrP monoclonal antibodies.
But it wasn’t the day for traditional prion diseases as speaker after speaker took the stage to claim prion pathology for other neurodegenerative diseases; and not just Parkinson’s disease (PD) or multiple system atrophy MSA. Neil Cashman gave an excellent talk on propagated misfolding (what a buzzword) in SOD1 motor neurone disease (MND) and also hinted at potential treatment with antibodies. Marc Diamond looked at tau prions and how their spread may be tracked by FRET-based biosensor cell assay (a mouthful).
J Paul Taylor looked at the role of RNA binding proteins (RBPs) in several neuodegenerative diseases including MND and frontotemporal dementia (FTD). And yes, these RBPs show prion-like activity.
There was an interesting case-based session on chronic traumatic encephalopathy (CTE). This was led by Jeffrey Kutcher, possibly the foremost authority on this neurodegenerative condition. I learnt that CTE is a post-mortem diagnosis and that in life the diagnosis should be restricted to traumatic encephalopathy syndrome (TES).
The day was rounded up by two excellent debates on stroke treatment. Marc Chimowitz took on Graeme Hankey on the comparative advantages of dual and single antiplatelets for secondary stroke prevention; it was the battle of the lumpers versus the splitters and it was probably a draw. Jeffrey Saver was however the clear winner over Colin Derdeyn by arguing for the combined use of thrombolysis and thrombectomy, rather than thromectomy alone.
Its day 3 about to start at the American Neurological Association (ANA) annual conference. As a follow up tp my previous posts, this is a quick take on 6 new buzzwords for me from day 2. These are at the cutting edge of neurology
Metagenomic deep sequencing. This promises to solve the pervasive problem of undiagnosed encephalitis and meningitis. James Wilson’s talk was heavy; here is a link to an abstract which hopefully simplifies things
Neuroprosthesis. The future of re-animation of paralysed limbs after spinal cord injury. Hunter Peckam’s website
Brain-machine interface. Krishna Shinoy presentation seems more SciFi than neurology. Harnessing the power of the will to communicate. Here he is explaining things
Neurofascin and Contactin-1 antibodies. Just a few more antibodies to muddy the waters of immune-mediated neuropathies. Cutting edge review by Alan Pestronk of NeuroWUSTL fame
Sequestosome and Matrin-3 syndromes of adult onset myopathies. No wonder many of our cases go undiagnosed. Margherita Milone‘s talk went slightly over my head but my gut feeling says this is important
Mitophagy. Another culprit process contributing to traffiking problems in motor neurone disease. Teepu Siddique was erudite
MS epidemiologists and researchers dissected the topic Causes/Triggers of MS. Speakers were David Hafler, Alberto Aschiero, Lisa Barcellos and Larry Steinman. And the top 6 are
Genetics
Tobacco smoking
Vitamin D deficiency
EBV infection
Overweight in early age
High salt intake
I suggested to David we should only be looking for correlation rather than causation (an idea I picked up from a great book Big Data).
He strongly disagreed! He believes genome wide association studies (GAS) have confirmed the cause for MS. I think the search for a definite cause is probably futile but we define cause flexibly. Alberto made the point that even if all the known risk factors were eliminated, MS will still be very prevalent
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