Islet Cell Regeneration and the gene INGAP, Part 2

Edited chat on www.childrenwithdiabetes.com/chat
Date: December 10, 1998, 10:00 EST
Melissa Davis, moderator.
Subject: Islet Cell Regeneration and INGAP, Part II
Guest: Dr. Aaron I. Vinik, Research Director, Strelitz Diabetes Institutes
Eastern Virginia Medical School, Norfolk, Virginia

Dr. Aaron Vinik
Hello all, I am online and happy to answer any questions that you might have.

I will try to briefly summarize our research on islet regeneration. Some years ago we noticed that wrapping a hamster pancreas in saran led to the formation of new islets. We harnessed this property and explored what it was that happened in a pancreas that allowed it to make new islets when wrapped. It turned out that the wrapped pancreas was making a protein that we called ilotropin that was capable of stimulating pancreatic islets to grow when injected into other animals. We have now found that ilotropin contains a protein we have called INGAP that is capable of doing the same thing. We have treated animals with INGAP and have been able to reverse streptozotocin-induced diabetes in a proportion of these animals. We have found the gene for INGAP and are busily working to find the best way to give INGAP, how much to give, by what route and if it is possible to turn the gene on without giving the protein.

Sandy Donchess
Dr. Vinik, can you tell us what kinds of animals have been given INGAP?

Dr. Aaron Vinik
We have so far given INGAP only to hamsters. We plan on giving it to other animals when we have discovered how much we need to give and the best form and route to use for its administration.

Brad
Dr. Vinik, are there any harmful side effects you've found in the hamsters you've administered INGAP to?

Dr. Aaron Vinik
So far we have not found any evidence of toxicity of INGAP when administered to hamsters. The surprising thing is that INGAP appears to target very specific cells in the pancreas and no other site. Even more important is that when it is expressed, it occurs only in the regenerating pancreas and no other tissue. For these reasons, we do not expect it to be toxic and do not expect it to have untoward effects on any other tissue.

Sandy Donchess
Dr. Vinik, have any of the hamsters been cured of diabetes? Also, how often do they have to be given INGAP?

Alan F. Bachrach, M.D.
What series of steps must be taken, and what obstacles do you see must be overcome before INGAP may be used clinically?

Dr. Aaron Vinik
We are making a whole lot of progress with INGAP, and the immediate step is to see if we can optimize dose and route of administration so that we can effectively treat 100% of animals not the cure of 30-40% we have thus far achieved. We think that there may be other factors in Ilotropin that are conducive to the optimum effects of INGAP, and we are seeking these out. The question that will arise is that if you have a shot at curing 30-40%, why not go for it immediately, and in this regard, we need to do all the pharmacology and pharmacodynamics to be comfortable that we can go ahead with human studies. Clearly, that will require significant financial support and backing.

Brad
When I hear the word cure I think to myself, I've been waiting better than 40 years to hear this even at a success rate of 30-40%, it sounds almost unbelievable. It sounds as though many of us may actually be able to witness this before too long, or am I misunderstanding something?

Dr. Aaron Vinik
It is mind boggling to think that you could get even a 30-40% cure rate, and we would like to capitalize on this. This was of course in streptozotocin -induced diabetes in hamsters but, if this is directly translatable to humans, it will be very rewarding.

Alan F. Bachrach, M.D.
Thanks, but it all seems so simple. The notion that all you have to do is administer a protein which causes differentiation of islets faster than the autoimmune process can destroy them is mind boggling in its simplicity. Do antibodies develop to INGAP? I must say that unless there are some intolerable side effects, the notion of delivering INGAP by injection doesn't bother me, as long as it will achieve euglycemia and prevent long-term complications.

Sandy Donchess
Dr. Vinik, Dr. Rolland Hebert recently stated that he was speaking to or collaborating with you and your team with respect to his claims about a "supplement" that seems to regenerate beta cells. Is this true?

Dr. Aaron Vinik
Yes, I do know Dr Hebert. We have had several conversations, and he has been in contact with the people in my laboratory. So far, we have received an extract from him to test in the laboratory in vitro. We were unable to show that the extract had any effects on stimulating ductal cells to grow. More recently he has asked me if we would test the extract in live animals, and we would be delighted to do so.

Sonia Cooper
Dr. Vinik, your discovery is very interesting. Are you collaborating with Drs. Hering and Sutherland?

Dr. Aaron Vinik
We do have collaborators all over the world, but Dr. Sutherland, who is well-funded for his research on transplantation is not one of them. We intrinsically believe that transplantation can only solve the problem for very few people with diabetes and only when the problems with rejection and spontaneous cell death have been overcome. For this reason, we have elected to collaborate with people who can assist us in bringing the idea that islets can regenerate to fruition.

Sandy Donchess
Dr. Vinik, I guess I have a very basic question. Does the autoimmune process actually destroy beta cells? I don't understand how a dead cell can be brought back to life, so to speak.

Dr. Aaron Vinik
We have not yet found that animals develop antibodies to INGAP when it is administered by the intraperitoneal or subcutaneous route. We have, however, only used Western blots to detect these antibodies, but the technique may be too crude to allow us to find soluble antibodies. We are working at the assay using radio labeled INGAP to see if we can improve the sensitivity.

Alan F. Bachrach, M.D.
As I understand it, the dead islet cells are not "brought back to life." Rather, "primordial" stem cells which have not yet differentiated into islets cells are stimulated to do so by INGAP. If this is not true, please correct me.

Dr. Aaron Vinik
Dead cells cannot be brought back to life. In fact, islet cells have a very low rate of replication even when they are alive. Many people have tried to make islets multiply-especially those people doing islet transplants. Some of the successful islet transplants have required 12 donors to treat one person. There just would not be enough donors around to treat the people who need it. That is why people are anxious to find a means of making islets expand. The primordial stem cell is present in the pancreas even years after the onset of diabetes. It is this cell that can be rejuvenated to differentiate into an adult endocrine cell.

Alan F. Bachrach, M.D.
Dr. Vinik, Just curious... What was it about wrapping those hamster pancreases in saran wrap that encouraged them to produce INGAP. Did the Saran wrap damage them and cause them to "try to regenerate?"

Melissa
This is probably a silly question... but what inspired you to use saran wrap on a pancreas? Is saran wrap a common article found in a laboratory?

Dr. Aaron Vinik
Why saran? Well, the truth is that it was cellophane originally, but cellophane is the same as saran. Saran is freely available in the lab, and the wrap we use is the little band that you find on cigarette cartons. This seemed to work best of all. Why we thought of doing it was for an entirely different reason. We were trying to create a model of pancreatitis so that we could learn why when the process started, it became relentless. We failed in this mission but noted that all the wrapped pancreases had 2-4 fold the number of islets. The wrapping process produces a partial obstruction that initiates the production of INGAP.

Melissa
Wow! I'll never look at wrapped leftovers the same again!

Tomokazu Ise
Dr. Vinik, are you planning to extract human Ilotropin and INGAP from human pancreas?

Dr. Aaron Vinik
Hi there Dr. Tomokazu, we have already extracted human INGAP and isolated the human INGAP gene. We published this in the Journal of Clinical Investigation, May 1997.

Melissa
Here it is!

Tina
Dr. Vinik, do you need to do more than one injection of INGAP in order to achieve the desired result?

Dr. Aaron Vinik
In the animal studies we have done this far we have given daily injections of INGAP for several weeks. We do not yet know how many are required, how often, what route and so forth. We have only recently had enough of the recombinant form of INGAP available to us to do these experiments that are so vital before we can plan the human equivalents.

Ruth
Dr.Vinik, do you feel that a lack of funding is slowing the rate of your research ?

Dr. Aaron Vinik
This is always the problem. I am not saying you simply want to throw money at a problem and think that will solve it. When you have something as promising as INGAP, intensifying the financial support with added minds and scientists will now doubt bring us to a solution earlier and thereby bring closer the day when we can do this in humans. We had a perfect example of this when, a couple of years ago, the Diabetes Institutes Foundation in Norfolk poured extra resources into the lab and a project on trying to find the gene. The gene research, which would have taken many years, was accomplished in just two.

Sandra Silvestri
Dr. Vinik, were funding problems the reason you entered a relationship with Lilly regarding INGAP?

Dr. Aaron Vinik
We entered into a relationship with Lilly for a number of reasons. Lilly has outstanding scientists with expertise in protein chemistry and molecular biology. They have been a great help in advancing the project. It is also clear that when one wants to transfer a research project from science into the arena of producing a drug, many many dollars are required, and deep pockets are essential.

However, Lilly has funded their own internal research on INGAP but has not supported ours. We have been primarily dependent on the Diabetes Institutes Foundation. Some other charities also help to fund this work.

Sandy Donchess
Dr. Vinik, I spoke with a Lilly researcher who said that INGAP would require years of research. Can you tell us what Lilly is researching, and if your research is different?

Dr. Aaron Vinik
Sandy, Lilly is researching turning INGAP into a drug, and we are trying to find ways of delivering it, whether it will be the protein or gene that should be given, if we can turn it on by other means or if the target or receptor can be found and activated. Ultimately, our goals are similar, but we go about the problem very differently, and the approach to making a drug and furthering the science are not exactly the same. I hope that helps you understand the differences.

Sonia Cooper
Back to the idea of collaboration and follow-up on Dr. Bachrach's observations. Your model of stimulating growth combined with something like anti-CD3 to suppress the TH1 attack seems like an ideal protocol for new onset patients that still have some working islets. What do you think of a model of simultaneously stimulating growth with INGAP and suppressing the attack with anti-CD3?

Dr. Aaron Vinik
I like the idea of simultaneously giving INGAP and anti-CD3 or for that matter any agent that will suppress the immune response so that the newly formed islets will be protected from immune destruction. We have, however, been able to prevent and reverse the diabetes in the NOD mouse that as you know gets an immune form of destruction. We can only presume that the rate of regeneration outstripped the rate of destruction. We do believe that the pancreatic islet cell mass is dependent upon a balance between formation and destruction. In the past, it was a one way street and destruction was always the victor. We think we now have the means of outstripping the destructive forces but would welcome any means of evening out the battlefield.

Judith
Dr. Vinik, what controls the replication of the islets when you stimulate production with INGAP? Have there been problems with hyperinsulinism?

Dr. Aaron Vinik
I like the question of whether or not we could go the other way and get hyperinsulinism or even excessive growth of islets. What appears to be the case is that we are recreating normal ontogeny, i.e. it is a re-enactment of what happens to the fetus in utero. When the islets have reached a critical number and size, they cease growing. We have not seen inappropriately high insulin levels, nor have we seen pathologic increases in islet size or number. The normal restraining forces seem to be present and restrict unbridled growth.

Judith
That IS good news re: control of growth. I would think possible induction of malignancy would be a major concern.

Tina
Have you been able to determine whether the "humanly induced" growth rate of islet cells causes the animals to have low blood sugar?

Dr. Aaron Vinik
The humanly induced growth of islet cells has so far not cause hypoglycemia. It is interesting that when we follow the animals over time, they start making more insulin than might be necessary, and the body compensates by increasing its production of glucose and reducing the effectiveness of the insulin. With time, there is a resetting of the homeostasis and the insulin levels return towards normal and the need for increased glucose production disappears.

MAR
"It is interesting that when we follow the animals over time, they start making more insulin than might be necessary and the body compensates by increasing its production of glucose and reducing the effectiveness of the insulin. With time there is a resetting of the homeostasis and the insulin levels return towards normal."

Dr. Vinik, you are a master of understatement if you refer to this as "interesting." I find this amazingly encouraging...miraculous. There's some hope here.

Ruth
Dr.Vinik, what is the recombinant form of INGAP. Why has it only been very recently available?

Dr. Aaron Vinik
The recombinant form of INGAP has been made in bacteria or in a cell tumor line using the INGAP gene as template. We needed first to identify the gene and then to develop a method that would work on making the protein in such a way that it assumed all the necessary primary and secondary characteristics that allow a protein to do its thing. In this respect,when we found the gene, working with Lilly had a great deal to do with manufacturing the full length protein from the gene template since they had developed the method for other proteins and had the expertise in house.

Marina
This may be totally dumb but I'm going to risk it. Is INGAP kind of like an oncagene? I remember vaguely learning about how cancer is caused by a gene that is turned "on" (sometimes by stress). INGAP seems to turn itself on during times of pancreatic stress and result in mass replication. Is there any correlation here?

Dr. Aaron Vinik
Induction of malignancy is of great concern whenever one stimulates growth. We have observed animals for a lifetime and have yet to find a malignancy.

Judith
Again...VERY good news!
And what approach will be used to prevent autoimmune destruction of the induced islets?

Dr. Aaron Vinik
The principle of action of oncogenes and factors that stimulate growth is not dissimilar. Your question is a smart one even if you don't believe it. For tumors to develop, one usually needs more than one hit, i.e. oncogene activation together with loss of some restraining activity or the activation of other pathways simultaneously. The difference between that and what one observes with INGAP treatment is that the growth is entirely regulated, there is only one hit, there is no loss of the restraining potential nor do we interfere with it. Nonetheless, we are vigilant for any signs that this might not be the case. We have not yet encountered a malignancy even in the lifetime of animals we have treated.

To answer the question of how late in the course of diabetes will this treatment be feasible. I tried to suggest to you that we think it may be indefinite when I relayed to you the story of the 65 year old male who had neogenesis and INGAP expression after having had type 1 diabetes virtually his whole life. It seems that these primordial cells are present in the lining system of the pancreas, and that they are particularly hardy to all forms of assaults - alcohol and poisons amongst others.

Judith
So you believe you can continue to induce an infinite number of islets, keeping ahead of autoimmune destruction?

Alan F. Bachrach, M.D.
So, does it appear that INGAP alone will be a treatment for DM. This would not eliminate all the injections (I presume they would be required in an ongoing manner) of medications. I presume that one would no longer have to check glucose levels multiple times per day. Anything else?

Dr. Aaron Vinik
Alan, those are interesting speculations. Some of the islet transplant work has been claimed as being successful if the dose of insulin was reduced! Our target is to have people insulin free, and that is the reason we are not sitting back and enjoying the 30-40% response.

Alan F. Bachrach, M.D
What I am really asking is.... do you think INGAP can be used alone, or will it be part of a regimen of drugs necessary to achieve euglycemia?

Dr. Aaron Vinik
Alan, if INGAP does what we hope it will and the individual is not far along the path of complications requiring other forms of intervention, it should be the sole treatment.

Alan F. Bachrach, M.D.
Dr. Vinik, That's great news. To me it really suggests that things are relatively far along (ignoring the FDA requirements for bringing a drug to market, of course!). Thanks for joining us.

Sandy Donchess
Before human clinical trials, would it be necessary to do animals such as mice, dogs, primates, etc?

Ruth
Dr.Vinik. I'm confused now. What animals have studies been done on so far? I thought that I understood that they were done on hamsters, mice, dogs, and monkeys? Is that correct? Will your main focus now be on administration problems such as dosage and means of administering the protein?

Dr. Aaron Vinik
Ruth, you were not confused. We have identified INGAP in all the species you mention as well as seeing it when we have induced neogenesis. We have only treated hamsters with the recombinant INGAP and Ilotropin.

Sonia Cooper
Are you working at all with Chris Newgard's group on producing a bioengineered cell line? I apologize for continuing back toward collaboration, but it seems like this is helpful in obtaining accelerated funding.

Dr. Aaron Vinik
Sonia, we are not working with Chris Newgard's group on producing a bioengineered cell. This is proving to be a bigger undertaking than most people anticipated in the beginning. The key difference is that we do not start with malignant cells or a clonal cell line but with a primordial cell and encourage it to differentiate and make insulin. We do not have to worry if it has the recognition machinery for glucose or that it will turn off in the absence of glucose or that it will resume its malignant characteristics in the body.

Sandy Donchess
Thank you so very much, Dr. Vinik, for being here and providing these explanations. I appreciate it very much, and I know everyone else does, too.

Dr. Aaron Vinik
Thank you all again for the super questions. Good Night all and thanks for being there. AIV

Brenda
Thank you Dr. Vinik for giving us parents more hope for the future for our children!! Good night all...

Sonia Cooper
For those looking to read some abstracts, just do a search on PubMed using the keywords "Vinik and diabetes" or INGAP at
http://www.ncbi.nlm.nih.gov/PubMed/
If you want automatic updates, you can put these key words into search tools that will give you weekly updates to any new publications....

Ruth
Dr.Vinik Thank you for your discovery, the hope it brings, and for taking the time to inform us tonight. Good night.