Category: Type 2 diabetes

Stem cells and Type 2 diabetes

Tuesday 1 December 2009

I wrote this, as part of my work, in response to someone enquiring about paying for stem cell treatments for Type 2 diabetes. I think there is an awful lot of work to be done in this area before that’s doable, but am aware that there is research into bone marrow stem cells and Type 2 diabetes (ie it’s a bit early, but it’s not actually a crazy idea).

This should not be taken as gospel (I might be wrong) nor as medical advice (I’m not medically trained) but I hope will be useful nonetheless 🙂

I’ve tweaked my response for this blog.

All views expressed are mine alone and do not necessarily reflect the views of my employer.

Dear ________

The research into stem cells and diabetes is not yet at the stage where it would be appropriate to start putting such cells into people with the intention of using this as a therapy (ie in the hope of improving symptoms).

There have been some small trials where people have received stem cell transplants, under very particular conditions, to ‘see what happens’ and to get an idea of the safety (or not) of doing this.

Companies offering stem cell transplants are, to the best of my knowledge, not involved in clinical trials but are instead claiming this as a therapy, and charging for it. Without sufficient evidence from clinical trials that show that stem cells can actually help people with Type 2 diabetes and that the transplants are safe in the long run then this sort of intervention is rather speculative.

There is nothing wrong with a clinical trial to see if transplanting stem cells can help but prospective patients are not usually asked to pay. Also there are very strict regulations for clinical trials in place to protect participants. People travelling abroad for stem cell transplants do not have this protection if anything goes wrong. The science journal Nature has an interesting blog post on charging people for unproven stem cell treatments http://blogs.nature.com/reports/theniche/2008/03/patients_paying_for_stem_cells.html

At this stage it is not exactly clear how a stem cell transplant would help someone with Type 2 diabetes. As insulin resistance is generally the major problem (that is, insulin can still be produced by the cells of the pancreas but the body becomes less able to respond to it) then adding in more insulin-producing cells would not necessarily be an appropriate way to treat that problem.

It is certainly true that Type 2 diabetes is a progressive condition (which effectively means that the way in which the condition is treated changes over time) and the insulin-producing cells may well begin to fail after a while, meaning that less insulin can be produced. Of course it makes sense, theoretically, that someone in this situation could benefit from replacement insulin-producing cells – however we do not yet have the evidence that stem cell transplants can help.

The cells used in these transplants are generally the patient’s own bone marrow stem cells. These cells have the capacity to form a limited number of blood cells (including cells of the immune system) and they do not naturally form insulin-producing cells. While it is possible to modify cells in a laboratory to persuade them to secrete insulin the modified cells may not be very safe for transplantation.

I do want to stress that scientists are not discounting the possibility that transplanting bone marrow stem cells into people with Type 2 diabetes could help – it is possible that the presence of these blood-type cells could help to ‘rescue’ in some way the pancreatic cells from further damage and so improve blood glucose levels. It’s less likely that the cells would spontaneously form insulin-producing cells, but it’s not impossible.

A report of a recent trial (with 25 patients) suggested that this might be a possibility (http://www.physorg.com/news157534107.html) – but this research is at an early stage and it would be unlikely for patients to have to pay for this.

We do not know what the long-term effects of giving stem cell transplants are and one particular case study has caused concern among researchers and doctors http://news.bbc.co.uk/1/hi/health/7894486.stm

Interestingly several case studies have suggested that bone marrow transplants (given to children suffering from leukaemia) may actually be linked with a subsequent worsening of glucose metabolism and insulin resistance http://www.ncbi.nlm.nih.gov/pubmed/11041401

I would recommend this brief (eight pages) patients’ guide to stem cell treatments http://www.isscr.org/clinical_trans/pdfs/ISSCRPatientHandbook.pdf and seek advice from your own doctor before committing any money to unproven treatments.

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Hypoglycaemia and Type 2 diabetes

Following the BBC news online’s article about the effects of hypoglycaemia on cognitive function in people with Type 2 diabetes I thought I’d post up some info about the various treatments used by people with Type 2 diabetes and how they affect blood glucose levels. More on the story on Diabetes UK’s website. Thanks to @mocost for highlighting this being in the wider media

NOTE: I am not medically trained – this information cannot replace proper medical advice or treatment. If you are worried dial 999 or if you are mildly concerned NHS Direct 0845 46 47.

Do not rely on anything I have written here, thank you 🙂

What is hypoglycaemia / a hypo?
Hypoglycaemia (literally low – glucose – blood, or ‘hypo’) occurs when blood glucose levels fall below 4mmol/l. The body responds with a series of symptoms (sweating, shaking, pins and needles in the lips, irritability, hunger, headache – they vary!) that alert the person that their blood glucose levels are falling which will hopefully encourage them to take something sugary to restore blood glucose levels.

Treating hypoglycaemia
Advice on what a hypo is and how to treat one – Hypoglycaemia and Hypos – what to do (Diabetes UK).

Slightly more medically-detailed advice on treating hypos – Hypoglycaemia (British National Formulary – email registration required, but it is free)

What drugs are used in treating Type 2 diabetes?
People with Type 2 diabetes who are not taking insulin injections are much less likely to experience serious hypoglycaemia however it’s important to be aware that the pills used in treating Type 2 diabetes can cause hypoglycaemia under certain circumstances, by virtue of the fact that they lower blood glucose levels by any of several methods.

(note: PLEASE inform your doctor if you are taking any other herbal preparation in addition to medication as there can be interactions which may affect how each works, and this may worsen hypos).

According to the British National Formulary (BNF) hypoglycaemia arising from “an oral antidiabetic drug should be transferred to hospital because the hypoglycaemic effects of these drugs may persist for many hours.”How do the various drugs work and which are more likely to cause hypoglycaemia?

Using the British National Formulary numbering system for drug types…

6.1.1 Insulins – these act directly to lower blood glucose levels and can cause hypoglycaemia (hypos) if more insulin is injected than is currently needed. Highest risk of hypos.

6.1.2.1 Sulphonylureas
Names of drugs include chlorpropamide (not much used), glibenclamide, gliclazide, tolbutamide, glimepiride and glipizide.

All of these work by helping the pancreas to produce more insulin and so all can increase the risk of hypoglycaemia. “All may cause hypoglycaemia but this is uncommon and usually indicates excessive dosage. Sulphonylurea-induced hypoglycaemia may persist for many hours and must always be treated in hospital.” Source: BNF (link above, registration required)

6.1.2.2 Biguanides
Metformin is the only example in this class of drugs. It works by enhancing uptake and use of blood glucose while discouraging the liver from creating extra glucose from scratch (the process of gluconeogenesis) – it’s very unlikely to cause hypoglycaemia.

6.1.2.3 Other antidiabetic drugs
Acarbose – delays the digestion and absorption of carbohydrates (eg starch and sucrose) because it inhibits the enzyme that breaks chains of glucose (in sucrose it’s a small chain of glucose and fructose, but in starch it’s long chains of glucose). Less likely to cause hypoglycaemia (lower risk).

Nateglinide / repaglinide – stimulate insulin release so have the potential to cause hypos, however are short acting.

Thiazolidinediones (pioglitazone / rosiglitazone) – lower insulin resistance (which is the same as increasing insulin sensitivity) which makes insulin more effective at lowering glucose and so these pills can cause hypos.

DPP-IV inhibitors (sitagliptin / vildagliptin) – when a meal containing glucose arrives in the intestine a gut hormone called GLP-1 is secreted into the bloodstream. This ‘goes on ahead’ to the pancreas alerting it that glucose is on its way into the bloodstream and enhances the release of insulin. GLP-1 is quickly broken down by the enzyme DPP-IV (DPP-4 / dipeptidyl peptidase-4) but sitagliptin and vildagliptin are enzyme blockers, enabling GLP-1 to persist for longer. Their effect is to enhance insulin secretion so they can cause hypos.

Incretin hormones
Exenatide – is a synthetic form of GLP-1 that is less quickly broken down by the DPP-IV enzyme and so it too acts to increase insulin secretion and so can cause hypos.

Spotted a mistake or omission? Don’t be shy – let me know!

Disclaimer: Anything posted here is my opinion and not necessarily that of my employer.