Wednesday, March 12, 2008

Mitochondrial Un-coupling (!)

How about that for the title of a post!

OK, this morning there were two stories about this research, one on Science Daily and one on Eureka Alert.

The fight against obesity -- a new insight - Mitochondrial uncoupling demonstrated in human skeletal muscle

With obesity still on the increase, it appears that the main weapon in the fight against it - reducing energy consumption by eating less - is ineffective. There is evident need to search for new treatment strategies dealing with the opposite aspect of the energy balance: increasing energy consumption. Researchers at Maastricht University have now found a way to increase cells’ energy consumption: mitochondrial uncoupling. The findings are published in this week’s PLoS ONE.

PhD candidate Sander Wijers and his colleagues Patrick Schrauwen, Prof. Wim Saris and Wouter van Marken Lichtenbelt have shown that this process occurs naturally in human skeletal muscle cells when exposed to mild cold. They carried out muscle biopsies on 11 lean, healthy male subjects both under normal and mild cold conditions. Their results could lead to the development of drugs that stimulate mitochondrial uncoupling, and thus contribute to obesity treatment.

Fats and sugars are broken down in the mitochondria, or energy factories of the cells. ATP - the energy source used, for example, when muscles contract and for many other cellular processes - is formed using the energy released in this process. In some cases, such as when exposed to cold, not all the energy released from sugars and fats is used to produce ATP; stored energy is used for heat, reducing the availability of ATP for cellular processes. This phenomenon is called mitochondrial uncoupling. Fats and sugars are still broken down in the uncoupled mitochondria, but the energy released is not entirely used for cellular processes. More energy is therefore required to carry out the same physical functions.

Got that?

Now, what else has been shown to induce mitochondrial uncoupling? A low carb / ketogenic diet: The ketogenic diet increases mitochondrial uncoupling protein levels and activity.

The Eureka story also said: More energy is (therefore) required to carry out the same physical functions

I wonder if this process is related to the whole metabolic advantage debate that has been getting Colpo and Eades so agitated?


Peter said...

Wow. Ketogenesis for uncoupling sounds fine, might help for those Edinburgh winters. Drug induced, no thanks!!!!!!!!!!!!!!


Chris said...

Cheers Peter.

I suppose the other option to promote this would be cold showers!

Stephan Guyenet said...

Interesting. The canonical view is that mice have UCP activity but humans don't (except as infants). Mice are capable of non-shivering thermogenesis using a tissue called brown adipose tissue. Human infants have it too, but we lose it as we develop.

That's why we have to shiver to generate heat, instead of just pumping up our UCP activity. But maybe we do have a limited ability to do it after all...

Peter said...

Brrrrrrrrrrrrrrrrrrrrr and I thought surfing the North Sea in January was cool, or should I say cold! Live too far in land now.