We hear about the additional dangers that come with visceral fat since it surrounds our internal organs. However, does this make subcutaneous fat less dangerous? In an article about adipose tissue macrophages, Wentworth et al show that the macrophage profile differs between subcutaneous (under the skin) and omental (a part of the visceral tissue) tissue in samples taken from women. In subcutaneous fat, they showed a more dense population of adipose tissue macrophages with CD11c+ than in visceral fat. These macrophages have pro-inflammatory entities, one example is a protein related to reactive oxygen species release (CD11c+). Reactive oxygen species (ROS), which are related to stress, can lead to further inflammation and immune response. In regards to obesity, the group of scientists suggested that subcutaneous tissue may play a greater role in inflammation and insulin resistance than omental tissue. The inflammation may result from CD11c+ macrophages containing increased mitochondria concentration and mitochondria activity as well as fat concentration, entities that would increase ROS production.
The interesting article caught my eye in its focus on subcutaneous tissue over omental tissue regarding obesity and inflammation. There is no doubt that visceral fat should be kept in check. However, the comparative amount of subcutaneous tissue usually out weights the amount of visceral fat in any one person. The pure amount of pro-inflammatory CD11c+ cells could be the reason why they have such an effect on insulin resistance. More specifically, it could play a part in how individuals continue to experience states of chronic inflammation. Sine this data was taken from female samples, it would be interesting to test the article’s hypotheses in men, children and across cultures to see if the results are consistent.
Looking at obesity through an inflammation perspective brings up the fascinating topic of adipocytes functioning as an immune organ. Exploring adipocytes and adipose tissue macrophages the past two weeks has shown the possibility of fat specific immune cells leading to inflammation. Especially through this article, it provides a reason to care about subcutaneous fat. Even though the imminent threat of visceral tissue is present, the mere amount of subcutaneous fat can also pose a serious problem to an individual’s health.
Wentworth, John, et al. Pro-Inflammatory CD11c+ CD206+‑ Adipose tissue Macrophages Are associated with Insulin resistance in Human Obesity. Diabetes 2010; 59:1648-1656.
If subcutaneous adipose tissue has both a greater inflammatory response and is in greater abundance than visceral adipose tissue, how did visceral tissue get the reputation as the bad fat?
ReplyDeleteSierra, we cannot conclude from this study that only used female data about the effects of subcutaneous adipose tissue and visceral adipose tissue. Therefore, further studies that take into account different factors such as male subjects; different age groups, different socioeconomic backgrounds and etc are needed to test the validity of this study. So I think visceral fat is still the bad fat.
ReplyDeleteAn interesting study was done by Joslin Diabetes Center and Harvard Medical School on subcutaneous (SC) and visceral (VIS) fat. They transplanted SC from donor mice to VIS region (cavity) of the recipient mice. Recipient mice showed decreased body weight, glucose, insulin, and total fat mass levels. Also, the mice’s glucose uptake and insulin sensitivity improved. However, when SC was transplanted to SC area the result wasn’t as satisfactory. They observe no change when VIS fat was transplanted to the VIS region. Their conclusion was that SC fat is different than VIS fat and improves glucose metabolism.
I apologize if I mislead you. I brought up this article, not to discredit the information about visceral fat, but to shed light on the possible affects of the macrophages in subcutaneous fat (specifically in women) on obesity. Agreeing with GhizaIN7630, I do feel that visceral fat is still bad.
ReplyDeleteThank you for bringing up the study GhizaIN7630. It is quite interesting. I wonder if there are similar affects in humans similar to the mouse model. I do agree that visceral and subcutaneous fat are different. It would be interesting to see what makes them different and if those differences can explain the affect on glucose metabolism. The article in the original post showed differences in adipocyte tissue macrophages between the two types of fat -- I bet there's more. Hopefully I can look into it more articles this week.
I think that we allow subcutaneous fat tissue to be thought of as okay fat because it is easier to lose and isn’t as dangerous as visceral fat. However, visceral fat usually occurs when there is a large amount of subcutaneous fat already in tacked. I think that if someone only had visceral fat that they would have harsher health effects than someone with just subcutaneous fat, but having only one or the other rarely occurs. We know visceral fat is worse because of its effects on our organs. Subcutaneous fat is dangerous in its amount because there is usually a greater amount of it on our bodies than visceral fat on our organs. I think that the study being on women makes it even harder to make conclusions about the inflammation process because of the hormones females have that males do not. I found Ghiza’s study that she quoted interesting, it shows us that the fats are different not just in location but of chemical properties also, it gives another reason why he effects of the two different fats are also different.
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