Interviews

Interview with Prof. Dr. Joachim Reidl

Due to our special interest in microbial behavior of our system in the human guts, we talked to University Professor Joachim Reidl from the Karl Franzens University, Graz about our project. Professor Reidl is working at the Institute of Molecular Biosciences and his research field especially includes Medical Microbiology.
Regarding our project, he told us, that it will be very interesting to observe the differences in terms of regulation of your quorum sense based system in E. coli Nissle 1917, due to the big difference to ordinary lab strains like E. coli BL-21. He also mentioned that it would be interesting to find out to what extend the intestinally produced L-DOPA really goes into the blood stream and subsequently how much of it reaches the brain. It needs to be determined how much L-DOPA is produced in vivo in comparison to a standard lab reactor experiment.
Furthermore, this would be especially important to discriminate the exact amount of bacteria that has to be brought and cultivated in the human gut. According to web resources [1], medication such as “Levodopa” is usually administrated to patients in doses from 500 mg to 6000 mg a day. In previous work done on L-DOPA metabolic engineering, researchers developed E. coli strains that were able to produce up to 1.51 g/l of L-DOPA in 50 hours in batch reactors [2], meaning that we would have to improve these results significantly to actually develop a sufficient production strain that can be administrated directly to the human guts.
Another interesting aspect is the molecular mechanism of how bacteria would keep the information of Dopamine/L-DOPA synthesis. In the intestine, different to the fermenter where an antibiotic can be added, selection pressure would not be present. The latter would mean that the engineered bacteria eliminate their plasmids. To counteract this problem, integration into the bacterial chromosome could be approached or selection pressure with knocked out essential E. coli genes could be applied. Still, this is no guarantee for the integrated DNA or the plasmid to be kept intact by the bacteria because of possible cut out or mutation of the foreign DNA.

The main point we were able to take back to the lab from this discussion was that we will most probably not have to worry about our developed strain overgrowing the human gut composition. Actually there is a possibility that the strain may have difficulties reaching the required L-DOPA levels, this is a problem we will have to work on in the future.

Interview with Dr Monty Silverdale

Dr. Monty Silverdale is a consultant neurologist, honorary lecturer in Neuroscience at the Institute of Brain Behaviour and Mental Health at The University of Manchester. Dr. Silverdale’s research is about Parkinson’s Disease (PD) and non-motor symptoms. Dr Silverdale shared his valuable experience in treating PD, gave comprehensive answers to our questions and provided us with useful and specific feedback on our project.

Dr Silverdale told us that patients with motor fluctuations have three options: intrajejunal administration of levodopa, surgery (deep brain stimulation) and apomorphine. As DopaDoser works by administering L-DOPA in the gut, we asked him about the current method of delivery, intrajejunal tubes, which use Levodopa gel, called ‘Duodopa’. There are multiple problems with intrajejunal tubes, not only are they prohibitively expensive, but they have other complications: ‘they get infected, they block and move out of the jejunum to the stomach… all sorts of stuff happens.’ For this reason, very few patients can use this option as it can cost tens of thousands of pounds for a single treatment. As our project, DopaDoser, is cheap and non-invasive, we wanted to know more about chronic pain and how our treatment method will improve on current options.

There are multiple non-motor symptoms associated with PD, one of which is thought to be chronic pain. There has previously not been much research into pain in PD, however Dr Monty Silverdale thinks that approximately ‘80% of people with PD have chronic pains, some of them have barely got any mobility issues but they still get chronic pain…’. He is trying to see if there is a link: to determine what percentage of people with dyskinesia actually have pain. ‘…some patients have bad dystonia and bad pain, but some have bad dystonia and no bad pain. That is why we are doing the study – we are looking at genetic polymorphisms that might predispose to pain…’.

We therefore asked him about DopaDoser and how he thinks a Continuous Dopaminergic Stimulation would affect people suffering from chronic pain, and if it might reduce symptoms. He told us: ‘If you had continuous dopaminergic stimulation… the pain will be less, because there will be less peaks and troughs – off-period pain goes and dyskinetic pain will go – there still be some pain left, but you would reduce it. Optimizing PD control will certainly improve pain.’

Dr Silverdale also commented on controversy of GMO in patients’ guts. He thought that there would be few problems with acceptability, particularly within the current research community.

As a final pointer, he gave us a few suggestions on how we could improve our project in the future. He told us that producing dopamine in the gut is not a viable idea as it induces vomiting in patients. This made us re-assess that area of our project and re-consider the dopamine pathway. He also mentioned using a dopamine receptor to regulate levels of L-DOPA. He said: ‘could that [a sensor] be a dopamine receptor… Could you use that? If it actually works, that would be pretty revolutionary in PD treatment, I would have thought.’

To conclude, it seems that DopaDoser has the potential to both alleviate pain and be a much cheaper, viable option for Continuous Dopaminergic Stimulation in a multitude of patients experiencing non-motor symptoms or dyskinesia. We took Dr Silverdale’s ideas on board and modified our project accordingly, and hope that in the future our project could be developed further to include use of dopaminergic sensors.

This interview showed:

• Current treatment (duodopa) is invasive and not effective
• Non-motor symptoms are often underestimated and not treated
• Peaks and throughs in medication conentraion should be minimized, because they can cause internalization of dopamine receptors
• DopaDoser will alleviate pain that is induced by fluctuations in levodopa concentration and treat not noticed non-motor fluctuations like depression, blood and bowel conditions, sleep etc.
• DopaDoser is cheaper and safer and less invasive
• Patients will accept DopaDoser
• DopaDoser should not synthesize dopamine
• DopaDoser is may be improved by a dopamine receptor and MAO-B and COMT inhibitors

Interview with Prof. Dr. Christoph Högenauer

In order to find out more about human gut bacteria composition we met Prof. Dr. Christoph Högenauer from the Institute of Gastroenterology and Hepatology at the Medical University of Graz.
We found out that composition of gastrointestinal colonization is not only different from person to person but also depends on geographic location, genetic disposition, possible disease and current eating habits. Quantification of these bacteria strains is quite difficult as some might only be abundant in very low concentrations. For actual quantification, q-PCR is the method of choice. However, Escherichia coli makes up 0,1-1% off all gut bacteria but up to 50% during enteritis [1].
Our selected probiotic E. coli strain Nissle1917 is currently sold under the trademark Mutaflor ®. If applied to the patient only once it is observed that the strain does not stay in the gut permanently but has a lifetime of only a few days and is not detectable after a week. Regular administration is still required.

Interestingly during our interview, Dr Högenauer also told us that he was also working with Parkinson’s patients, preparing them for a therapy form called Duodopa ® from Abbott [2]. This therapy especially serves patients that cannot take L-DOPA pills for varying reasons (intolerance or too high tolerance to oral L-DOPA). It is a special way for administration of L-DOPA (Levodopa ®) directly into the human jejunum through a PEG-PEJ tube. This approach allows for a continuous and stable dosage of L-DOPA over the whole day. However some major problems of this approach are high costs (around 700€ per week plus costs for placement of the tube and aftercare) and wear out of the tube every 2 years. Also the system needs to be rinsed on a daily basis and during the night medication has to be taken oral anyways. This ads up to 100.000 € per year per patient.

Obviously this is exactly where our project comes into play! Our idea allows for continuous administration of L-DOPA straight into the gastrointestinal tract which does not only get rid of tubes going into your body but also allows for a much smaller concentration of L-DOPA administration. Levodopa is currently applied through Duodopa® in concentrations of 20-200mg per hour, in contrast to previously mentioned pills in the multi gram range. Gastrointestinal production of L-DOPA would not only allow for a better lifestyle for patients but also discharge health insurance funds.

Interview with Prof. Angela Tod

Professor Angela Tod is the Florence Nightingale Foundation Chair of Clinical Nursing Practice Research at the Faculty of Medical and Human Sciences at the University of Manchester. Her research focuses primarily on access to health services as well as health inequalities during which she has worked with Parkinson’s patients and Parkinson’s UK. [1]

Interview with Dr. Mariella Kögl-Wallner

To get some more information on the medical aspects on Parkinson’s we visited Dr. Mariella Kögl-Wallner, an expert in therapy of Parkinson’s patients at the Institute of Neurology at the Medical University of Graz. We mainly talked to her about the daily burden of people with Parkinson’s disease. Since medications against Parkinson’s disease have become well established, patients do not have any reduced life expectancy. Still, the treatment means a lot of change in every day life of a patient. Levodopa® has to be taken dependent on the status of the disease several times a day at least 30 minutes before a meal and can result in peaks and shortages of L-Dopa. Those “off” times (periods with no symptomatic relief) [2] and dyskinesia [1] often cause a more progressive pathology. Compared to the traditional Levodopa® therapy, the application of Duodopa® already has some advantages over the oral medications. With this therapy method, a mostly constant L-Dopa level can be reached in the blood, meals do not have to be considered and no blockers like MAO-B (monoaminooxidase blockers) have to be taken.

Dr. Mariella Kögl-Wallner told us that her patients are usually very keen to take part in the testing of potentially new drugs. Furthermore, she confirmed that none of her patients would reject a therapy that includes genetically engineered bacteria as long as they see a positive effect about it. Not only the patients but also the doctors always try to stay on top of the latest research results about Parkinson’s disease, to find new ways how Parkinson’s might be treated or some day even be cured. Regarding diagnostics, Dr. Kögl-Wallner told us that they always sequence a few specific genes at locations where most of the patients show mutations. Still, there are groups of patients where those locations do not show any conspicuity. Those patients might have mutations in other locations of the human genome that have not been studied yet.

All in all, there are still many gaps of knowledge when it comes to Parkinson’s disease. A lot of research is done in this particular area. But ever since 2004 where Duodopa® was approved in Europe no other breakthroughs have occurred. Transplantable dopamine neurons produced from stem cells [3] or gene therapeutic approaches might one day become the therapy of choice for Parkinson’s patients.