There is significant data from research that suggests low oxygenation (hypoxia) in the adipose tissue of the obese could be a risk factor for chronic inflammation. For example a study that was conducted showed that the control lean mice had a partial pressure of oxygen of 47.9mm Hg. In the obese mice the partial pressure of oxygen was only 15.2 mm Hg. As you can see this is a substantial difference. This represents a 70% reduction in oxygen. To verify the relationship between obesity and hypoxia the researchers reduced the calorie intake of the mice. Once the mice started to lose weight they saw an improvement not only in oxygenation of the adipose tissue but most importantly there was a reduction in inflammation.
We know that hypoxia leads to chronic inflammation through the expression of inflammatory genes but we still don’t know the exact mechanisms of how hypoxia is generated in the adipose tissue of the obese. One concept presented in the article was (ATBF) adipose tissue blood flow. Researchers speculate that ATBF might be a possibility for the cause of hypoxia. A generator for ATBF is thought to be Insulin sensitivity. I know that there are still other factors that we must consider besides obesity and ATBF. For example VEGF was the only gene that was not increased in the ob/ob mice. VEGF is a vasodilator so this could possibly help with the low oxygenation of adipose tissue. Since VEGF is controlled by the gene HIF-1-alpha (hypoxia inducible factor 1 alpha) more research into this specific gene could prove to be valuable. Studies have shown that hypoxia is a major cause of inflammation so once we understand how to control hypoxia we could then begin to reduce chronic inflammation significantly.
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The problems associated with hypoxia as related to morbid obesity in the mice could be related to a vast majority of things (ex. smaller contractions in the diaphragm because of excess weight that must be raised to inflate the lungs; incativity due to obesity). The researchers saw a decrease in the weight of the mice and an increase in oxygen, this makes sense based off what I stated above. How this all comes back to inflammation though is just a small part of a big picture in my opinion. The hypoxic complications with obesity are practically common knowledge in the field of medicine. If a morbidly obese person does not have sleep apnea you question the diagnoses and medical provider, not the determination of wether or not they have the disease.
Wow...David, you make some very interesting statements in this comment! I knew about the issues with sleep apnea as well as the inability to breath well due to excess weight, but hadn't considered that as a possible reason for the hypoxia. Very interesting...
we do see an association with people who are obese and sleep apnoea. Since sleep apnoea does cause these people at times to stop breathing for a second or so while they are sleeping then this low oxygenation could tie into inflammation. im glad that you brought this subject up.
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