One of our founding members Dr Mary Kearney recently travelled to Strasbourg to attend the FARA Scientific Symposium on Friedreich’s Ataxia. She gives us an outline of the conference below.
Thursday – May 5th 2011
I went to this conference on the understanding that it was a scientific conference. I did not expect a cure, nevertheless I think as an FA parent one always comes away from such a conference a little disappointed that there was not some glimmer of hope that a cure was on the horizon. What I got from this conference was a better understanding of the breadth of research which is being undertaken internationally. I hope to give you a summary and explain some of the difficulties researchers face in their fight for a cure for FA.
The conference started on Thursday in glorious sunshine. Dr Hélène Puccio hard worked long hours in conjunction with many more including Ron Bartek to bring the programme to fruition. Prof Koenig jokingly announced at the end of the meeting that due to Strasbourg contribution to global warming , IGBMC managed to have good weather in for the conference
Clinical Discovery & Impact
This session discussed several areas which clinicians had found in their own area of practice.
Dr Miriam Cnop, Eramus Hospital, Brussels opened the scientific meeting with her talk on how diabetes in FA patients differs from non-FA patients. She studied 41 FAers’ 26 carriers and 53 healthy controls who were not known to have diabetes. She studied fasting glucose and glucose levels 2 hours after eating. She found that there was no difference between the fasting glucose levels. She found a difference in the glucose levels after 2 hours between the FA patients and the controls. Normally when a person eats there is a release of insulin from the pancreas to reduce the blood glucose level. This did not happened in the FA patients and it suggests that the impact of reduced frataxin on pancreas function needs further evaluation which is currently being undertaken in vivo and in vitro models for the disease.
The Australians led by Dr Lousie Corben reported on their study which examined brain function. It felt that the connection between different parts of the brain were affected and caused a failure in effective management of the control of movement. Dr Arnie Koeppen, Abany, New York gave his findings on how iron, copper and zinc distribution is altered in FA.
Dr Stephane Schmucker, Strasbourg presented a clinical case of a 10 year old boy with FA like symptoms but who had no repeat expansion for FA on genetic testing. He send the sample to Prof Michel Koenig’s lab for further testing and the lab found that he had a point mutation on both alleles that caused FA. The group involved in this case felt it was important to present it as it shows that possible is under-recognised. The group proposed that frataxin gene sequencing should be preformed more often in cases with isolated motor symptoms even if pure sensory neuropathy is lacking.
Pathways Impacted in FA
(This session was as you could expect from the title was very technical. Most of the presentations in this area were interlinked with the first session the following morning’s session called genetics, epigenetics and regulation. People reading this document might find it useful to read another document I have compiled explaining the concepts in epigenetic and regulation).
This area has been the subject of much debate since the discovery of the gene in 1996. It was Prof Pandolfo who initially linked frataxin functions with a disruption in iron metabolism. Since then much laboratory work and many debates at conferences have taken place about this concept. It is generally agreed that several proteins, enzymes and pathways are complex.
At present, cardiac mitochondrial protein is being investigated by a group at Dr Mark Payne’s laboratory in Indianapolis, USA. Studies to identify the hyperacetylated cardiac mitochondrial proteins in FA and to determine the functional significance of altered acetylation at particular lysine residues are in progress. At Dr Marek Napierala’s laboratory in Texas, USA they have identified miRNA signature of FA cells and evaluated the role of expressed miRNA as potential regulators of the intracellular iron metabolism and important players in FA pathogenesis.
Other topics discussed included, yeast frataxin mutant cells, the role of Sirtiuns (SIRT3) (Marcua Haigis, Harvard Medical School, USA) in FA and specifically in heart muscle, results of oxidative stress in YG8 mouse models, the role of iron regulatory protein (IRP 1) in iron dysregulation observed in FA, the role of microRNA and iron metabolism in FA.
The session ended with the keynote speaker, Dr Giovanni Mamfredi from Cornell University, New York. Keynote addresses are aimed to have FA researchers think “outside the box” I feel he spurred the enthusiasm of the researchers with his talk on mitrochondria. Mitochondria are often described as the powerhouse of the cell i.e. where all the work goes on. Frataxin is closely linked with mitochondria. Motor neurons can run the whole length of leg and a s result mitochondria move the whole length of the leg in both directions.
Dr Mamfredi area of special expertise is Amytropic Lateral Sclerosis which is a progressive neurological disorder and is also known as motor neurone disease. He found significant changes in the mitochondria at cellular level which included – as mitochondria got older they can become more fragmented. In ALS the mitochondria become smaller, they are less dense, there are less of them, and in particular there are less of them at the synapses. As a result the nerve degenerates further at neuro-muscular junction and the muscle losses its nerve supply and there is a loss of function. In his laboratory he can actually look at sciatic nerve in live mouse model. He wondered if this approach would have any relevance for FA or would mitochondrial dynamics be potential therapeutic target for FA.
19:30 – Welcome Reception – Palais des Rohan, 5 Place du Château, Strasbourg
This was a welcome break after the intellectual hectic day at the University. The Rohan Palace is one of the most important buildings in Strasbourg. It represents not only the high point of local baroque architecture but also houses three of the most important museums in the city since the end of the 19th century – The Archaeological Museum, The Museum of Decorative Arts and Museum of Fine Arts, There we were welcomes to Strasbourg by the Major of Strasbourg. It was back to work at 8:30 the next morning.
Friday – May 6th 2011
Genetics, Epigenetics & Regulation (instability)
(People reading this document might find it useful to read the other attached document explaining the concepts in epigenetic and regulation).
The triplet repeat expansion in FA occurs at the level of transcription through repeats. This session opened with Dr Edward Grabczyk, Prof of Genetics, New Orleans, USA telling us that we needed to understand the causes of the GAA-TTC repeat so that we can
1. learn how to halt FA progression
2. avoid unwanted side effects of potential treatment aimed at increasing frataxin gene transcription
This was a very technical talk area. It focused on the problem of a long GAA repeat and how they interfere with the cell’s ability to keep working Dr Villaseñor, Basel, Switzerland spoke about intronic expansion of GAA triplets in the FNX-encoding gene, which plays a crucial role in mitochondrial iron metabolism, causes gene silencing and thus reduced FXN protein levels. Although it is widely assumed that GAA repeats block transcription via the assembly of an inaccessible chromatin structure marked by the methylated H3K9, direct proof of this is lacking until Dr Villasñor presented these findings at the conference.
Dr Barondeau, Texas University, USA an invited speaker, outlined the fact that while we know that frataxin is depleted in FA which in turn results in the inactivation of iron sulphur clusters. Most researchers agree that frataxin functions in the biogenesis of Fe-S clusters but its precise role in this process is unclear. Several presentations followed from laboratories all over Europe and America detailing other proteins involved. It was considered that it was an area which would need to be revisited.
Models of FA
Despite the title of this session, the talks focused on the use of stem cell therapy to make models of FA. Over the years yeast, flies, worms and mice have been used to test hypothesis and drug treatment for FA. As none of these models are perfect, attention is now focused on developing new models for FA using induced pluripotent stem cells. This research has taken place in Australia, UK and Strasbourg. Even prior to the meeting, there has been great co-operation between groups as evidenced by the fact that stem cells models from Strasbourg have been given to Prof Pandolfo’s lab in Brussels for further work. The French, at Prof Rustin laboratory, have recently developed a zebrafish embryo as animal model for FA. It has the advantage that there is no colour on its outside and muscles and nerves can easily be seen.
There were 3 presentations from Australia which demonstrated how they have made a heart suitable for a mouse from stem cells. A video of the beating heart was demonstrated the end product effectively. The keynote lecture in this area was from Prof Martin Pera, currently working USA and soon to transfer back to Australia. He has worked in the area of stem cell research for a number of years. He told us that there is a lot of published research in this area which only started in 2003 – In fact there are 2,416 articles of which 455 are reviews. He said that there are several barriers to producing induced pluri-potent stem cells (iPSC). Epigenetics is really re-setting genes and he questioned what actually happens when you do that. He also wanted to know if scientists had figured out how to maintain the cells in a pluri-potent state.
Saturday – May 7th 2011
Drug Discovery & Development
This session started with Dr Rob Wilson, Philadelphia, USA talking about High-throughput screening (HTS) which is a method for scientific experimentation especially used in drug discovery. Using robotics, data processing and control software, liquid handling devices, and sensitive detectors, High-Throughput Screening or HTS allows a researcher to quickly conduct millions of biochemical, genetic or pharmacological tests. Through this process one can rapidly identify active compounds, antibodies or genes which modulate a particular bio-molecular pathway. The results of these experiments provide starting points for drug design and for understanding the interaction or role of a particular biochemical process in biology. Dr Wilson told us that out of a library of 2,400 drugs tested in the yeast model from US – 450 were shown to have potential relevance for the treatment of Friedreich’s ataxia.
The discussion again hypothesized on the functions of frataxin. This is the key to any drug that will be able to help FA. Some of frataxin functions have been proven other are only hypothesized. There was healthy discussion between scientists among the unproven function of frataxin. All were very interested in the subject and keen to get information about frataxin functions in an effort to help FA. The Australians have also done the high input screening looking for compounds which might help as have the Cortopassi lab in California, USA. Dr Sundi Sahdeo warned the audience that some of the drugs discussed could be toxic and were being used in a “delicate population” i.e. FA patients. He advised care should be exercised at all times. Dr Richard Festenstein, London has been looking at the use of the HDACi- Nicotinamide in the hetrochromatin formation in FA in mice and proof of concept studies are planned in humans. Dr Jacques, Repligen, Brussels has been looking ad HDAci which could penetrate the blood brain barrier. This is important as a lot of the problems in FA are actually within the brain. The session finished with a talk from Dr Javier Diaz-Nido, Madrid, Spain on brain-derived neurotrophic factor inhibiting neuro-degeneration triggered by frataxin gene silencing.
A group of 10 patients in Naples, Italy were treated with Epoetin alfa and the findings were presented by Dr Franesco Saccà. The drug was given by injection. It was shown to be safe and well tolerated. Some of the patients did develop a raised haemocrit and on reducing the dosage of EPO the haemocrit returned to normal. The dose of EPO was reduced in these patients, who subsequently tolerated the changed dosage and they continued in the study. There was an increase in frataxin production in these patients blood cells which remained raised for 1 year after administration of EPO.
An open label compassionate using deferiprone was carried out in Turin, Italy and Dr Antoio Piga, Haematologist, reported on it. Deferiprone can cross the blood brain barrier and it is thought that it works by clearing some of the toxic mitochondrial iron. He had 19 patients for the study. He found that the therapeutic range of deferiprone was narrow. Three patients developed agranulocytosis and 7 patients had a low white cell count. 11 out of 19 (mostly females) developed iron deficient anemia. This was treated with low dose iron taken at least 4 hours before or after deferiprone. The findings from the study suggest that long term therapy with deferiprone is able to help cardiac disease in patients with Friedreich’s ataxia. A randomized controlled trial is needed to confirm this hypothesis.
An international six-month double-blind randomized, placebo-controlled study investigating the safety and tolerability of Deferiprone in FA was presented by Dr F Tricta, ApoPharma. 72 patients were involved in this study. There was a placebo group, a low, medium and high dose deferiprone group. The low and medium group tolerated deferiprone but the high dose group did not. Two of the high dose group developed headache, severe dizziness and worsening ataxic symptoms. A as result this arm of the study was stopped.
Dr David Lynch, Philadelphia, USA presented the data from a 12 month open label extension study (IONIA_E) He told us that the study population was highly selective and motivated group. It was a young population. No ECHO was carried out during this period. Examinations were conducted at 3 monthly intervals which some experts consider too frequent. The study indicated that a dose of idebenone on 1350/2250mg/day may offer a therapeutic benefit to paediatric FA patients except in the area of standing and walking.
Biomarkers & Functional Measures & Clinical Design
Deciding on a measure of disease activity is an ongoing struggle for researchers to get agreement over the years. There is no biomarker to date and no recent research is available on this area. Ataxia rating scales were discussed and the new news on that is that the SARA scale should be considered for measuring FA. Dr David Lynch would prefer composite scales himself but “one size does not fit all” and it was generally agreed that the scale you would use would depend on what you wanted to measure.
Santhera under the guidance of Dr Metz made an interesting presentation on the ICASR ratings and demographic data that they have accumulated from over 600 FA patients. While the results are difficult to explain in this short report, he showed that some measures go from 0-77 in a very short space of time. This phenomenon is also known as ceiling to floor effect and is well demonstrated by the examination which assesses truncal ataxia with the eyes closed.
Measures of Neurologic progress in FA from USA’s Collaborative Clinical Research Network (CCRN) in FA revealed that different ataxia measures are reliable but it is still necessary to have at least 50 FA patients in each clinical trial.
The final two presentations related to biomarkers in FA. There was a presentation from an international group presented by Dr Evans-Galea, Australia on frataxin methylation revealing new insight into the FA disease mechanism. It may be possible that two region on the frataxin in two accessible tissues could be useful clinical biomarkers. The final word was given to Dr Rob Wilson, Philadelphia, USA on gene therapy in intractable CNS diseases. It gave the audience considerable food for thought.