Stem cells and diabetes (i)

Lots to say on this topic, so will have to break it up into manageable pieces using multiple posts!

Something I’ve been getting an increasing number of enquiries about is stem cell transplants for diabetes as there are a number of companies making the claim that they can cure the condition. I’m not aware of any evidence for this (beyond the company’s own claims, based on patient testimony – which is no guarantee of truth or accuracy) so am inclined to be very wary.

It seems that bone marrow cells are removed from the patient and purified (or otherwise modified in some way) before being returned to the patient in the hope of improving their blood glucose levels.

Bone marrow stem cells are able to form a fairly limited number of blood type cells – I’m not convinced how easy it is for them to transdifferentiate into insulin-producing cells once replaced in the body. If they’re modified before transplantation then I’d want to know a bit more about the safety of the modification procedure. The sort of laboratory tweaking that can be done to cells is generally performed only for research purposes and could preclude the cells from being suitable for transplantation.

It’s often claimed that because the stem cells are the person’s own cells there will be no issue of tissue rejection. This may not be true.

Type 1 diabetes is caused by an underlying autoimmune disorder which seeks out, and destroys, the insulin-producing beta cells in the pancreas and de. If new insulin-producing cells are transplanted then there’s every reason to suspect that the autoimmune attack will recur and these will be destroyed too. I don’t think the immune system cares too much where insulin-producing cells come from, if they’re producing insulin then it seems that this is sufficient for them to be destroyed.

Sometimes it’s claimed that the transplanted cells ‘support’ the pancreas in some way, to help it to regenerate its own insulin-producing cells. Maybe, but this would surely just mean that that the cells the pancreas generates itself will be destroyed (which is exactly what happened during the development of Type 1 diabetes in the first place).

Companies are also claiming that transplanted cells can help people with Type 2 diabetes – but for these people it’s more likely that insulin resistance is the problem driving their diabetes rather than a lack of insulin. It’s not clear how adding in more insulin-producing cells would help.

It’s something I expect to come back to in this blog as the pace of research is pretty speedy – but just because research in an area is fast-moving it doesn’t mean that it’s appropriate to bend the research too quickly into a treatment.

Monya Baker of nature.com’s stem cell blog “The Niche” has written a post highlighting that “Patients paying for stem cells are probably getting bad science
http://blogs.nature.com/reports/theniche/2008/03/patients_paying_for_stem_cells.html

Good places to find out about the status of research is to see what clinical trials are being done at ClinicalTrials.gov and Current Controlled Trials.

Clinical Trialsdiabetes and stem cells results page.
Current Controlled Trialshttp://www.controlled-trials.com/mrct/ – type in diabetes and stem cells into the ‘search for’ box and put a tick by ‘all registers’ to search all of them or choose individual registers.

Note that the results may contain trials that are not specifically about the use of stem cells in the treatment OF diabetes, merely that diabetes might be mentioned somewhere as a keyword.

Jo

Disclaimer – all posts are my opinion and not necessarily those of my employer.

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