Wednesday, July 27, 2011

Advances in Diabetes Research -- without hESCs

Prominent foundations for diabetes research, led by the Juvenile Diabetes Research Foundation, have long been leading advocates for human embryonic stem cell research (hESCR), giving scant attention to the promise of adult stem cells and other alternatives to embryonic stem cells to treat this disease.

How ironic, then, that two of the most promising advances in treating diabetes have nothing at all to do with embryonic stem cells.

First, a little background. With regard to diabetes, it has long been medical orthodoxy that once the body’s insulin producing beta cells, found in the pancreas, are destroyed they are gone forever – they do not regenerate. Thus, the promise of stem cells to treat diabetes was that they could be coaxed into becoming insulin producing cells suitable for transplantation for those suffering with diabetes. Proponents of hESCR claimed that embryonic stem cells would prove ideal for this task.

It seems things are turning out differently from what they so confidently predicted.

Scientists have actually had very disappointing results in their efforts to transform hESCs into pure colonies of beta cells suitable for transplant.

However, in a recent issue of Cell Stem Cell, scientists report that induced pluripotent stem cells (iPSCs) derived from beta cells are very efficient at generating insulin producing cells that could be used for transplant.

The scientists involved in the study believe that because the iPSCs are derived from beta cells, they retain a “memory of what they once were,” thus making them actually more efficient than embryonic stem cells for generating insulin producing cells.

Lead researcher Professor Shimon Efrat of the Tel Aviv University stated, “This discovery promises to advance the development of cell replacement therapy for diabetics, possibly leading to an effective alternative to organ transplants.” He added, “When generated from human beta cells, pluripotent stem cells, these memory cells act as though they are receiving a prompt from their past life; the cells already have some understanding of their purpose, making them more efficient in generating beta cells.”

As promising as this development is, others involved in research on diabetes point out that as long as the body continues its auto-immune attack on the pancreas, where the insulin producing beta cells are found, transplanting new beta cells will not provide a permanent cure – the body will just attack these newly transplanted cells as well. So these researchers have turned their attention on finding ways to stop the auto-immune reaction against the beta cells.

In June, before a meeting of the American Diabetes Association in San Diego, Dr. Denise Faustman presented very positive findings in her research to stop the underlying auto-immune attack responsible for diabetes.

In her research with mice (which Do No Harm has closely followed and reported on over the years) Dr. Faustman found that BCG, a relatively inexpensive vaccine typically used to treat tuberculosis, also stops the auto-immune attack that destroys the insulin producing cells in the pancreas. At first, she thought this was just the first step in treatment, the second being to transplant donated islet cells now that the threat of attack had been ended.

But to her amazement, it seemed that the pancreas began to regenerate islet cells on its own, without the need for any newly-transplanted cells. This directly contradicted the prevailing orthodoxy that once an insulin producing cell is gone, it is gone (scientific consensus, anyone?). When she first published her results in 2001, they were so controversial that she was not allowed to use the term “regenerate” because the scientific community “knew” an organ could not regenerate itself.

In a 2003 paper published in Science, Faustman confirmed her finding and speculated the adult stem cells found in the spleen were responsible for aiding the pancreas to regenerate the islet cells.

This was met with even greater skepticism. Nonetheless, by 2007 her findings had been replicated in six other labs, both here and overseas.

At the June meeting in San Diego of the ADA, Faustman reported positive findings for the first use of her protocol in humans. Six patients who were diagnosed with diabetes for an average of 15 years were divided into one group that received low-level doses of the BCG vaccine and one group that received a placebo. All those receiving the vaccine showed reduced levels of the cell responsible for attacking the pancreas, as well as indications that new production of insulin had begun.

Faustman now hopes to expand her trial with a larger number of patients and to win FDA approval to increase the amount of BCG used to treat them.

So within a month of each other, we hear of two very promising findings in the treatment of diabetes. One showed that iPSCs should prove very useful in producing insulin producing cells for transplant should they be needed. And the other showed that transplants may not be needed at all if the auto-immune attack on the pancreas can be stopped, allowing the cells to regenerate on their own.

And the thundering silence you hear are the reports about all the advances using hESCs to treat diabetes.

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