Dean Pomerleau Posted April 13, 2016 Author Report Share Posted April 13, 2016 Gordo wrote: Brown Adipose Tissue Is Linked To A Distinct Thermoregulatory Response To Mild Cold In People (Full/Preliminary article is downloadable from above, this is very recent work) Great find Gordo! Very interesting study . It is part of a clinical trial to study BAT in humans, and particularly its potential to combat insulin resistance and obesity. Here is the table from the full text of the study showing the characteristics of the BAT+ and BAT- subjects: The only significant difference between groups was age - with the BAT+ group being almost 20 years younger on average than the BAT- group! Us oldsters are really at a disadvantage when it comes to BAT. The entire subject pool was pretty hefty, verging on obese, but the BAT+ group had a tendency to be a bit leaner. As you observed, the BAT+ group was able to maintain their core body temperature during CE, while the BAT- folks saw a drop in core temperature despite being slightly less cold-challenged than the BAT+ group (the ambient temperature was adjusted for each subject to be just above their individual shivering threshold and the BAT+ group had a lower ambient temperature threshold). This again shows that it may not be possible for cold-acclimated humans to increase core temperature in response to cold like is observed in rodents, but instead to simply to maintain it. It continues to amaze me how little BAT even BAT+ folks have - 67ml on average. That's only a little over 2oz. That's tiny. It's hard to believe so little tissue can be responsible for so much thermogenesis, and it makes me wonder whether BAT is working in concert with other thermogenic processes (sarcolipin-induced futile cycling in muscle sarcoplasmic reticulum perhaps?) in the BAT+ group to maintain body temperature during a cold challenge. Having measureable BAT may therefore be a marker for cold adaptation and/or genetic variations that heighten thermogenic capacity. I hope these researchers publish a lot more detailed investigation of the metabolism and blood measures in these subjects, per their promise in the clinical trial description. Gordo wrote: They found that supraclavicular skin/surface temperature measurements were a good method of measuring BAT activity. The last such measurement I took on myself after CE showed 96.0F. Can you remind me how you measure your skin temperature? I might be interested in doing the same, so we could compare notes. Thanks! --Dean --------------  Front. Physiol. | doi: 10.3389/fphys.2016.00129 Brown Adipose Tissue Is Linked To A Distinct Thermoregulatory Response To Mild Cold In People Maria Chondronikola1*, Elena Volpi1, Elisabet Borsheim1, Tony Chao1, Craig Porter1, Palam Annamalai1, Christina Yfanti1, Sebastien M. Labbe2, Nicholas M. Hurren1, Ioannis Malagaris1, Fernardo Cesani1 and Labros S. Sidossis1 1University of Texas Medical Branch, USA Brown adipose tissue (BAT) plays an important role in thermoregulation in rodents. Its role in temperature homeostasis in people is less studied. To this end, we recruited 18 men [8 individuals with no/minimal BAT activity (BAT-) and 10 with pronounced BAT activity (BAT+)]. Each volunteer participated in a 6 h, individualized, non-shivering cold exposure protocol. BAT was quantified using positron emission tomography/computed tomography. Body core and skin temperatures were measured using a telemetric pill and wireless thermistors, respectively. Core body temperature decreased during cold exposure in the BAT- group only (-0.34oC, 95% CI: -0.6 to -0.1, p = 0.03), while the cold-induced change in core temperature was significantly different between BAT+ and BAT- individuals (BAT+ vs. BAT-, 0.43oC, 95% CI: 0.20 to 0.65, p = 0.0014). BAT volume was associated with the cold-induced change in core temperature (p = 0.01) even after adjustment for age and adiposity. Compared to the BAT- group, BAT+ individuals tolerated a lower ambient temperature (BAT-: 20.6± 0.3oC vs. BAT+: 19.8 ± 0.3oC, p=0.035) without shivering. The cold-induced change in core temperature (r = 0.79, p = 0.001) and supraclavicular temperature (r = 0.58, p = 0.014) correlated with BAT volume, suggesting that these non-invasive measures can be potentially used as surrogate markers of BAT when other methods to detect BAT are not available or their use is not warranted. These results demonstrate a physiologically significant role for BAT in thermoregulation in people. This trial has been registered with Clinaltrials.gov: NCT01791114 https://clinicaltrials.gov/ct2/show/NCT01791114) Quote Link to comment Share on other sites More sharing options...
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