Read all about the New York Stem Cell Conference

 ….or at least, read even more about it!  

Back in January, we reported that sixty of the world’s leading stem cell research experts from 14 countries were brought together for the first time to shape the development of future international MND stem cell research.

The two-day conference in New York – organised by the MND Association in conjunction with the UK National Stem Cell Network; the Canadian Stem Cell Network; the New York Stem Cell Foundation; and the ALS Association of the USA (ALSA) – brought leading stem cell experts together under one roof in order to agree key areas of investigation in this exciting field of MND research.

You can catch up with what our director of research, Dr Brian Dickie said about the conference in seven Stem Cell Workshop blog posts. 

If you felt that Brian’s daily blogs from the beginning of the year weren’t enough, a more comprehensive report has just been published in the journal Amyotrophic Lateral Sclerosis, of which Brian is a co-author. The journal publishers have also kindly given permission for a version of the report to be available online, which can be downloaded from the ALS Association’s website.

The published report on the ALS Association’s website is not written in plain-english as it provides a thorough assessment of the ‘state of affairs’ of MND stem cell research for scientists – you may find it interesting none-the-less!

Stem cell conference part seven: Creating new and better models for MND

It was then back to the science. Prof Frank Soldner (Massachusetts Institute of Technology) provided an overview of a new and exciting way in which MND-causing genes can be introduced into human embryonic stem cells in order to study the disease. Traditional gene transfection techniques are rather uncontrolled, resulting in multiple copies of the gene being introduced in random parts of the human genome – both of which can affect normal cellular functioning. A new genome-editing technique allows the existing ‘normal’ gene within the stem cells to be converted directly into a ‘mutant’ gene, which should result in the creation of stem cell-derived motor neurones that are much more representative of those in the patient.

Of course, the other way of getting to this point is not to use embryonic stem cells, but instead to use induced pleuripotent stem (iPS) cells, generated from skin samples taken from inherited ALS patients with a known gene mutation. Prof Jeff Rothstein (Johns Hopkins University) provided an update on the US National ALS Cell Bank which to date has produced 30 iPS cell lines from patients with various known MND gene mutations. He stressed the need for a large number of well characterised  cells to be made available to the research community, as each one will be slightly different, putting it very succinctly with the statement: “You need more than one ‘human’ to test a hypothesis or a compound.”

The National ALS Cell Bank will create both motor neurones and a type of neurone support cell called ‘astrocytes’ from each iPS cell line.

We know very little about the different subtypes of astrocytes that are present in the central nervous system – we know that brain astrocytes are different from those in the spinal cord. Both Prof Rothstein and Prof Su-Chun Zhang (University of Wisconsin) highlighted recent research showing that there are marked ‘regional differences’ within the spinal cord itself.

Using different ‘cues’ Prof Zhang is able to develop subtypes of astrocytes similar to those found in different parts of the spinal cord. This information may be very important in understanding why the disease progresses so differently between one person and the next. As the emerging stem cell trials in MND are based on replacing and improving the astrocyte populations in the spinal cord, it is also likely to be important in maximising the chances of success in altering disease progression, by ensuring the stem cells turn into the right type of astrocyte, best able to support motor neurones around the site of injection.

Stem cell conference part six: unregulated treatments

The room was crowded at 8am for the first presentation of day two, from Dr Doug Sipp (RIKEN Institute, Japan) on ‘Unregulated ALS/MND treatments and public education’.  Dr Sipp provided an insightful and entertaining overview of the plethora of self-styled stem cell ‘clinics’ and the tactics they employ to attract business. During the talk, the song Snake Oil, by the country singer Steve Earle, kept going round my head…. 

“Ladies and gentlemen, attention please
Come in close so everyone can see
I got a tale to tell
A listen don’t cost a dime
And if you believe that, we’re gonna get along just fine….”

Time was given over for a discussion on the issue of unregulated treatments, moderated by Dr Rick Bedlack (Duke University) and involving myself and Steven Byer of the US charity ALS Worldwide. Dr Bedlack is one of the founders of ALSUntangled, a consortium of ALS clinicians that used the Internet and social media to investigate alternative and off-label ALS treatments. Although in its early stages of development, ALSUntangled is fast becoming a very important resource to people with MND, providing the sort of objective information that helps people to come to an informed choice on whether or not to pursue alternative approaches to treating their disease.

There was clear consensus among those in the room that clinicians, scientists and patient associations need to find mechanisms for working more closely together – in separating ‘hope from hype’ and providing a more accurate explanation of the potential uses of stem cells in both basic science and disease treatment. Stephen Byer talked about the two C’s: the need for closer Collaboration and sharing of information; and better methods of Communication. I added a third – Consistency – to the discussion. We don’t necessarily all need to be providing exactly the same message, as different individuals and organisations we may well have differing opinions, but we should be basing those opinions on the same level of information and understanding.

Stem cell conference part five: safety first for current human stem cell trials

One human neural stem cell line that has cleared the US Government’s regulatory hurdles is that developed by the biotechnology company Neuralstem. To date, nine patients have received implants of these cells with few complications reported. Two of the clinicians leading the study at Emory University, neurologist Jonathan Glass and neurosurgeon Nick Boulis, outlined the system that has been developed to ensure extremely accurate implantation into the spinal cord. Both clinicians stressed the importance of safety – the spinal surgery procedure was constantly tested, evaluated and refined, along with the creation of clear ‘stopping criteria’ during the three-hour period of surgery. In this trial, the central tenet of the hippocratic oath – primum non nocere (first, do no harm) – is taken very seriously indeed.

 

Daniel Offen, a representative from the Israeli company, Brainstorm, presented the strategy for their planned clinical studies using patients’ own stem cells from bone marrow (so called ‘mesenchymal’ stem cells), which have been modified to become more-‘astrocyte-like’ and have also been demonstrated to secrete neurotrophic factors.  

These cells will be administered by intrathecal or intramuscular injection. It is important to reiterate that the above preclinical and clinical studies mentioned above are not trying to create new motor neurones to ‘re-wire’ the nervous system.  Instead, the aim is to provide the surviving motor neurones with a supportive environment to try and fight off whatever is causing them to become damaged. It is also important to stress that the primary outcome of these early studies is to ensure the implants are safe.

 

Of course, implantation of mesenchymal stem cells have been tested before – albeit, not in the modified form that Brainstorm has developed. Dr Letizia Mazzini from University of Novara Italy has experience of performing such studies and has published her research in medial journals over the past few years. There have been no serious adverse events in the short or long-term related to the technique. Unfortunately, there was no strong evidence of any beneficial effect and it is not clear whether the cells actually survived long-term, once implanted. 

By 7pm, the presentations for Day 1 drew to a close, but a few glasses of wine in the next room ensured continued discussion. My brain was suffering from information overload…

 

And we still had another day to go…..

Stem cell conference part four: Laying the foundations for future stem cell clinical trials

The remainder of the morning covered some of the preclinical research that has laid the foundations for current and forthcoming clinicalstudies. Prof Clive Svendsen, from University Wisconsin-Madison, gave an overview of the strategy that helped lay the foundations for the current Neuralstem trial. This strategy involves the implantation of support cells (astrocytes) into the spinal cord. These astrocytes produce important nourishing (neurotrophic) factors that are essential to maintain the health of neurones. The strategy therefore is not about rewiring the nervous system, but instead providing the surviving motor neurones with a ‘boost’ to aid their survival.

He stressed the need for long and detailed study of the astrocyte cell lines if they are to be seriously considered as candidates for transplantation studies, using the comment “rubbish in, rubbish out”. He also provided very useful cautionary information in that some of the human cell lines show a tendency towards developing genetic changes over time, reminiscent of some types of tumours. By careful characterisation of the cell lines, his team was able to select only cells that demonstrated they were extremely stable. He has grafted these cells into the spinal cords of SOD1 rats, which does indeed help to protect the motor neurones.

However, it does not markedly alter the survival of the animals, probably due to the fact that the implanted cells can take months to mature into functional astrocytes, plus the fact that the motor neurones were still drawing back from the muscles and losing their connection. He is therefore looking at a ‘two-pronged attack’, treating both ends of the motor neurone through astrocyte implantation into the spinal cord, combined with nerve growth factor injections into the muscle.

Why stem cells derived astrocytes?
Astrocytes vastly outnumber neurones in the brain and spine: they are the cells that make up most of the ‘cellular neighbourhood’ and it is believed that in diseases such as MND, that neighbourhood is toxic to motor neurones. Prof Don Cleveland from University of California San Diego believes that if healthier, correctly functioning, astrocytes can be implanted into the spinal cord, it could turn the cellular neighbourhood into one that will protect the motor neurones and alter disease progression. The question is whether we can engraft enough cells to radically change the neighbourhood for good?

In colaboration with Prof Larry Goldstein, also from University California San Diego, his studies in SOD1 rats showed that injection of embryonic stem cell-derived human astrocytes can ‘clear the hurdles’ that need to be overcome in order to get astrocyte implantation studies into the clinic. Studies will move to a larger animal model and further work on producing, purifying and screening the cells needs to be done, in order to satisfy strict regulatory conditions.

He stressed the importance of setting milestones and getting the administration in place to deal with these hurdles. If all goes well in achieving these milestones, the plan is to be able to perform the first clinical studies in the next four years.

Stem cell conference part three: screening for beneficial drugs using stem cell technology

The possibility of using stem cells for drug screening was covered in more detail by Prof Chris Henderson from Columbia University New York. Prof Henderson has been a pioneer in drug screening in ALS: his work with the French biotechnology company, Trophos, which involved screening 50,000 drugs for a protective effect in rat motor neurones, formed the basis for the current clinical trial being performed by the company.

He went on to explain some of the challenges being encountered in developing a human stem cell drug screen – one of which is the fact that new motor neurones are being generated in the dish (a process called neurogenesis) over a prolonged period. If new motor neurones are constantly being born, it means that you do not have a stable baseline on which to test the effects of drugs. Prof Henderson outlined how they were getting around the problem and getting closer to a robust and reproducible model.

Stem cell conference part two: How are motor neurones created from stem cells?

Creating motor neurones for research is a lengthy and expensive process, so Prof Kevin Eggan from Harvard University  Massachusetts, asked whether we can predict at an early stage which stem cell lines will be the most useful in generating the best quantities of motor neurones, saving time, effort and money. He has been developing a ‘scorecard’ which he believes will help work out which cell lines are most useful.

But if you make motor neurones from skin cells, are they really motor neurones? At the moment there is no consensus on what makes a neurone a motor neurone, so Prof Eggan outlined a series of tests used in his lab that “provide confidence that these have more than a passing resemblance to motor neurones”. Additional encouraging results suggest that motor neurones created from ‘adult’ iPS cells are “pretty indistinguishable from those obtained from embryonic stem cells”. There are some differences, so comparative work using both types will need to continue for the forseeable future.

Prof Siddharthan Chandran, MND Association funded researcher at Edinburgh University then posed the question: “Do they reflect the different types of motor neurone found in the human body? There is no such thing as a ‘generic’ motor neurone, each one has its own postcode.”

So, can stem cell-derived motor neurones reflect the diversity of subtypes found in the human body? For example, the motor neurones that control eye movement are much more resistant to the disease than other motor neurone types, and motor neurone controlling limb muscles can behave differently from those controlling the trunk muscles.

The answer is preliminary, but encouraging.

Prof Hynek Wichterle, from the Columbia University New York, presented research showing that embryonic stem cells can be turned into different subtypes of motor neurone and Prof Chandran has been working on the same issue using iPS cells.

There is a lot of work to do, but having human motor neurones in a dish that faithfully reflect the diversity of types found in the body will greatly assist understanding of MND and may also help in identifying potential drugs that might target highly vulnerable motor neurone populations in patients with different clinical patterns of disease.

Stem cell conference part one: It begins…

It was a chilly -15^oC in New York on Sunday night, but the temperature on Monday morning was considerably higher – fuelled in part by anticipation of the presentations and debate to come – as 60 delegates from 14 countries gathered for a workshop on the use of stem cells in research and treatment of ALS/MND.

As many of the leading names in the field started filing into the meeting room, I found myself thinking (rather morbidly) that if the hotel blew up, research in this field would be set back a decade…

Learning from the past to push stem cell research forward
The opening session was motivating, with Dutch neurologist Prof Leonard van den Berg and MND Association funded researcher Prof Chris Shaw providing overviews of our current understanding of the causes of MND and the clinical and pathological ‘spectrum’ of the disease.

A lot of Prof Shaw’s presentation focused on the TDP-43 protein, which is a ‘pathological hallmark’ of dying motor neurones. It struck me that scientists understanding of TDP-43 appears to be accumulating faster than it did for SOD1, 15 years ago – a consequence of the advances in technology and the fact that there are many more researchers around the world working on MND these days.

Dr Lucie Bruijn, science director of our counterpart organisation in the USA –the ALS Association, concluded the opening session with a scene-setting presentation, highlighting the work that has been done over many years in developing motor neurone cell cultures (from mice and rats) and using these to screen for potential protective drugs.

There have been many challenges every step of the way, but the learning from these past studies will be vital in moving stem cell research forward in the future.

In the next few blog posts, I will take you on a whistle stop tour of the questions asked by 60 of the world’s leading MND stem cell researchers at the stem cell workshop and the answers we were met with so stay tuned…

Please also read our press release on our website  for more information on how we are helping to shape the future of stem cell research.