By: Scott R. King
Islet Transplantation – Available When?
In our April issue, Mr. Metabolism (Scott Robert King) wrote about the evolution of the islet transplant industry and invited questions. He has received several queries. These came through the Internet:
Q: I enjoyed your article in the April DIABETES HEALTH concerning the booming businesses connected to Islet transplants. I have several questions: Have you heard of a company called CEC Industries in Henderson, Nev.? I talked to them several times in August and September of 1994. They claimed to have acquired the rights to a patented technology able to obtain large numbers of purified islet cells from one organ donor. It was anticipated that the initial transplant would occur before the end of 1994. Several people named in promotional letters were Dr. Charles, director of UCI Diabetes Research Center and Dr. See, Medical Director Biospheres Technology Inc., Las Vegas, and Assistant Clinical Professor, University of California, Irvine. I have had no contact with them since October of 1994, and I am curious what happened to this work.
Another question: If successful, would there be a shortage of human islet cells for transplantation? Work is underway on using animal cells (mainly pork). What is the status of this research and how promising is it?
Thanks for keeping the info flowing. It is hard to come by.
via the internet
A: Thanks for your inquiry, John. I spoke to Todd at CEC Corporation }}}} and learned that they had planned to do a trial involving implantation of islets into the kidney of a diabetic kidney transplant recipient in 1994, as you described. However, due to lack of money, the trial has been indefinitely postponed. The technology they have, comes from Biosphere. It is a new method for isolation of islets of Langerhans. I am trying to learn more about this islet isolation technology.
Your second question is a good one. There are not nearly enough organ donors to meet the demand for islets. Most people active in the field regard pigs as the best source because they are numerous and their insulin is very similar to human insulin. I know that Boehringer-Mannheim, the largest manufacturer of the enzyme used to isolate islets, is focusing on enzymes for pig pancreases.
I agree that pigs are the most promising source . Over the years various people have advocated the use of dogs, rabbits, cows, and even whales!
Q: This is our first try at e-mail, so we hope it works. We have a daughter with type I diabetes. When do you think this treatment will be available on a widespread basis? Thank you!
via the internet
A: It will take many years, assuming it works! Working backwards, }}} review of a PMA (Pre Marketing Approval) by the FDA takes two to three years. The PMA cannot be submitted until the clinical trial is complete. In this case, it is likely that the FDA will require extensive follow up to assure safety of islets. My educated guess is that a trial will take three to six years. The biggest question is, when will be have a technology worthy of a major clinical trial? This is very hard to estimate.
Animal studies of encapsulated islets have been going on for 15 years! It is my own hope that some of the ideas we are working on will be ready for clinical studies in three years.
}Low Estimate}High Estimate
Technology Development}3 years}10 years
Clinical Trial}3 years}6 years
PMA Preparation}1 year}1 year
FDA Approval}2 years}3 years
TOTAL:}9 years}19 years
So I don’t see general availability until well into the 21st century.
Contact Scott R. King care of: DIABETES HEALTH, 3715 Balboa Street, San Francisco, CA 94121 or e-mail at: Scott@Rexhome.win.net
Nurse Has Exercise Questions
Q: I have started exercising once again to help control my diabetes better. It has been very difficult for me. Although I am not a sedentary person, I find it difficult to exercise. I am a RN working a busy medical/surgical unit. I walk up and down the hall all night, but I realize this isn’t the same as exercise.
Since I started exercising, my legs pain me something terrible. I do warm up about 10 minutes, then I try to walk the track. Within five minutes my legs feel as though they will explode.
I have gone to a vascular physician who checked my circulation and said I had great circulation. He thought the pain was due to lack of exercise in the past. I realize I haven’t exercised much, but I always walk a great deal at work. I do not understand why my legs would hurt so much while trying to exercise and not at work.
Could you give me some input or suggestions for my workout? The exercise periods are so painful I really have to force myself to continue them.
My workout usually consists of stretches for five to 10 minutes, walking the track or riding a bike for 10 minutes, lifting weights (light) for 15 to 20 minutes, then walking the track slowly for two to three laps (11 laps equals one mile). I exercise a total of 30 to 45 minutes. I have been trying to exercise either every day or every other day.
Please help me so I may continue a workout program for a healthier living.
Cheryl L. Bentley, RN
A: Your symptoms sound like intermittent claudication, but you state that a specialist examined your circulation and found it normal. The discomfort could also be caused by overexerting. By walking too fast and without adequate warm-up, your muscles may produce enough lactic acid which in combination with low oxygen content produces pain.
If your condition is caused by claudication, let me explain what it is and how exercise may be helpful. Claudication is caused by vessel blockage in arteries to your legs which results in reduced blood flow and pain during exercise. If claudication is the cause of your pain, walking while at work may not bother you because it probably occurs in short bursts alternated with periods of standing. The lack of blood flow and oxygen deprivation may not reach a threshold that elicits pain when walking for short periods. During continuous walking, you are more likely to reach that threshold.
Diabetics suffer vascular disease in far greater frequency than non-diabetics. We not only are prone to large vessel disease but also damage to the capillaries. A good exercise program and tight control of your blood glucose can retard further progression of your condition. As long as your doctor allows you to exercise, you can switch to a type of exercise that can be done with less discomfort. Cycling or swimming may be good alternatives. You didn’t indicate exactly where the pain occurs but I assume it is in the calves. These muscles are primary movers in walking but are not extensively used in swimming and cycling particularly if you place the middle of your foot on the pedal while cycling rather than the ball of the foot.
Regardless of whether the muscle pain is caused by claudication or simply unconditioned muscles, a progressive walking program should help. Walk slowly for three minutes and then sit down or slow the pace considerably for three minutes. Consider this the warm-up. Continue several cycles of slow walking followed by three minutes of rest or even slower walking. This will allow you to extend the time of walking and to condition the calf muscles and build more capillaries and small arteries feeding those muscles. As these changes occur, you should be able to walk for longer periods before the aching begins.
Realize that stretching is important but it does not increase blood flow into your muscles, so you need to walk slowly or cycle slowly for at least five minutes to warm-up the specific muscles you are going to use.
The walking you do on the job is still good exercise, and burns calories and may be helpful to your blood sugar control. Whatever the source of your discomfort, a walking program gradually increasing in duration and/or speed should help. Good luck!