Team:NTU-Taida/Human Practice/Doctor-Interview



Doctor Interview

For this part of human practice, we interview several doctors for a broad view of safety concern from professional angle. Most of the teams tackle with safety problem from the point of the interaction between engineered bacteria and environment. But the safety issue between engineered bacteria and human is less discussed. Host-engineered bacteria interaction is extremely important in our PepdEx project, so we interviewed doctors from different department of National Taiwan University Hospital (The best hospital in Taiwan) for their opinion on our PepdEx project. The suggestion can not only be used for the further improvement of our device, but can also provide a general concept of the safety issue that must be dealt with when synthetic biology encounters clinical medicine. These professional advices are valuable if we want to apply synthetic biology to medical field in the future.



Gastroenterologist, Department of Laboratory Medicine, National Taiwan University Hospital

“Maintenance of the target peptide functional concentration in the gut and the maintenance of sufficient colonies are the most big two questions that a clinical physician interested in the most”, said Dr. CHENG. After explaining to him about our neuropeptide delivering system and the safety system we designed, he commented, “That is really a good approach!”. Dr. CHENG also mentioned that we should consider the peptide bacterial advantages over the normal flora. To maintain the steady dosage of peptide each time the bacteria produced, We need to find a way to stabilize the bacterial colony number and the consistency over time. He noted that each antibiotic usage or even diarrhea can change the colony status. How to increase the bacterial surviving ability should be our main concern.

Wei-Chih LIAO

Gastroenterologist, Department of Internal Medicine, National Taiwan University Hospital

From the viewpoint of a gastroenterologist, doctor Wei-Chih Liao deal with the safety issues of our project from two aspects. First is uncertainty of the survival advantage of introduced bacteria. “When this peptide delivery bacteria is introduced into guts, it may have influence on the normal flora of intestine”, Doctor Liao said, “There is possibility of failed colonization without any safety problem; however, there is still possibility of breaking the normal balance of intestinal bacteria.” Although we designed to utilize enterobacteria of normal flora as a vector of our peptide delivery system, we still can’t ensure absolute safety due to the complexity of intestinal environment. Second, he concerned about the effects of synthetic GLP-1 on human body, “GLP-1 is a promising therapeutic candidate for weight controlling and diabetes. Other functions of GLP-1 have not been quietly understood, though.” In other words, our system might raise unwanted effects while synthetic GLP-1 regulates the energy balance of human body. Besides, whether this additional GLP-1 really regulates instead of disturbing the energy balance is another question. “Human being is complex. A slight change may result in whole difference, like the butterfly effect.” said Dr. Liao. Just like other new therapy undergoing large clinical trials, Doctor Liao suggested strict assessment and clinical trial should be done, then we could have a clear insight into the safety of our project based on the statistics.

Hsin-An HOU

Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital

After we introduce our PepdEx idea to Dr. Hou, he kindly provided us with four advices:

1) Since the bacteria is genetically engineered, we need to pay attention that they may cause some side effects, like transforming normal cells to immortalized cells, causing diarrhea or outcompeting normal flora.

2) Regarding that our device is a health-promoting design, the side effect should be strictly regulated. Therapies like anti-cancer drugs or antibiotics, their side effects are more acceptable because they are used to deal with already sick patients. However, if our product is designed for normal healthy people, the demand of low-side effect is higher.

3) Even though our bacterial are originally from normal flora, once taken out from the body and undergone in vitro manipulation, they need detailed regulation for any human clinical trial. Organizations like Good Clinical Practice (GCP) and Institutional Review Board (IRB) have strict rules and any human trial must be approved by their committee. Therefore if we want to start the human experiment, we have to obtain their approval.

4) Usually any new biological agent must first be proved effective in vitro, and then must be shown useful and safe in vivo (such as mice model), and can start human trial. For Phase I clinical trial, healthy participant will be treated to test the maximal safety tolerant dosage. Phase II will use patients as efficacy test. Phase III is similar but the sample size must be much larger. After the three clinical phases are done and the drug is proved to be safe and effective, it can finally enter the market. So if we want to make PepdEx available in the market, there is still a long way to go.

Wei-Tien CHANG

Department of Emergency Medicine, National Taiwan University Hospital

Dr. Chang held a promising attitude toward our project in 2012 iGEM contest----PEPDEX, the combination of Medicine and Synthetic Biology. The project “PEPDEX” of NTU-Taida team is aiming at developing a smart modified bacteria like E.coli which can deliver drugs whenever we want. “It’s a quite interesting idea and if it can really work, it will give opportunities and potentials in the field of Medicine.” Dr. Chang said. “Once your project carries out, it will surely benefit both patients and doctors”

In addition, Dr. Chang thought that the safety concerns in our project about putting the recombinant bacteria in our body may not be so serious in theory, “After all, the bacteria your team used is original from the enteron.” “However, it still have too many variables until proceeding the clinical test.”, Dr. Chang said. In his perspective, we still need to design rigorous experiment to test whether the modified bacteria would have side-effect on human body. “The project still has a long way to go before it succeeds, but I think PEPDEX is worth doing.” In conclusion, just like the other doctors our team member interviewed earlier, Dr. Chang said that he’ll be willing to use “PEPDEX” to cure his patients in the days we succeed.

Mei-Hwan WU

Pediatric Cardiologist, Chief of Pediatrics, National Taiwan University Hospital

Upon our introduction of synthetic biology and our project towards bacterium-based peptide therapy, Dr. Wu holds an open and encouraging attitude on these cutting edge concepts and techniques. The major concern of these synthetic approaches and their application on health and medicine is the complicated interaction between different components in the huge genetic networks. “There are a lot of unknown effects of genes in regards to human diseases. Some genes masked by others in one condition may show unpredictable effects in other conditions. We know so little about these interactions,” said Dr. Wu. For the safety issues, as a clinical doctor of pediatrics, she greatly relies on the scientific evidence of associated clinical trials, and will be glad to adopt these novel therapies after 1~2 year observation on the responses on the adults when the drugs enter the markets. She is optimistic about the blossoms and development of the synthetic biology-related application in medicine.

Chih-Kang CHIANG

Nephrologist, Department of Internal Medicine, National Taiwan University Hospital

For application of synthetic biology on medicine, doctor Chiang hold a positive and optimistic attitude. He agrees there are many benefits to use modified bacteria such as E.coli to deliver drugs, both for doctors and patients, yet he still has some concern. Though we have some methods to prevent bacteria from over proliferation, they are not reliable and controllable enough nowadays. Such as using antibiotics for selection, how could we totally prevent the drug resistance gene from horizontal transfer? On the other hand, if we take auxotrophic (organisms that have inability to synthesize organic compound required for growth) bacteria, which are easy to kill, since some kinds of bacteria (ex. E.coli) is easy to destroyed even they are still wild-type, modified ones might quickly die after we put them into practice, thus inefficient for application. Talking about our project PEPDEX, doctor Chiang think the idea is nice and prospective. The suicide mechanism seems feasible, but he also mentions that in theory, we can control the PEPDEX E.coli perfect, however in reality it’s not that simple when dealing with organisms. He says if someday we successfully construct a well-controlled drug delivering organism, He’ll be willing to use it to cure his patients.

Jing-Yu LEE

Director, Department of medicine, Boehringer Ingelheim Taiwan Ltd.

As a clinical research reviewer in an international pharmaceutical factory, Dr. Lee said that our project provides a brand new method to transport drugs to human body. Compared with traditional methods of delivering drugs to human body, our project combining both synthetic biology and medicine developed a smart way delivering drug in a mode of correctly responding to the change of environment, yet there are still some uncertainties we need to deal with. First, we need to ensure that the bacteria we make use of are stable and reliable enough so that they would not destroy the balance among other bacteria in human gut. Second, it is still possible that bacteria may contaminate the environment by stool. If we can overcome the problem above, the method would be a fantastic one both for doctors and patients.

Chung-Chin KUO

Chairperson Professor, Department of neurology, National Taiwan University Hospital

As a clinical neurologist and a neuro-scientist, Dr. Kuo thinks positively about our projects. He pointed out that the connection between central nervous system and the normal flora residing in the guts is a very new topic and requires much more efforts to make clear of how it really works. He also noticed that even though the current pilot studies showed good results, the actual mechanism and the target brain nucleus may require further elucidation. Back to our project, he agreed with our proposal, and thought it may one day be applicable. However, if we are seeking to fabricate the connection of peripheral to central nervous system by using engineered bacteria, we may need to start from basic animal model to prove the efficacy of PepDEX. As rampant grow of researches in neuroscience, Dr. Kuo encouraged us to put more efforts on it, and make our dream come true.