Adipose tissue growth and development: the modulating role of ambient temperature

Abstract

Adipose tissue is usually laid down in small amounts in the fetus and is characterised as possessing small amounts of the brown adipose tissue specific mitochondrial uncoupling protein 1 (UCP1). In adults, a primary factor determining the abundance and function of UCP1 is ambient temperature. Cold exposure causes activation and the rapid generation of heat through the free flow of protons across the mitochondria with no requirement to convert ADP to ATP. In rodents, housing at an ambient temperature below thermoneutrality promotes the appearance of beige like adipocytes. These arise as discrete regions of UCP1 containing cells in white fat depots. There is increasing evidence to show that, to gain credible translational results on brown and beige fat function in rodent models, they should be housed at thermoneutrality. This not only reflects the type of environment in which humans spend the majority of their time, but is in accord with the rise of global temperature caused by industrialisation and the uncontrolled burning of fossil fuels. There is now good evidence that stimulating brown fat in adult humans by nutritional or pharmacological interventions can improve glucose homeostasis. The challenge, therefore, is to establish credible developmental models in animals maintained at thermoneutrality which will elucidate the true impact of nutrition. The primary focus should fall specifically on the components of breast milk and how these modulate long term effects on brown or beige fat development and function.

Brown Adipose Tissue: New Challenges for Prevention of Childhood Obesity. A Narrative Review

“…BAT major activation occurs at birth upon cold exposure and B3 adrenergic stimulation [ 54 , 56 , 57 ]. The extra-uterine cold environment stimulates the thermogenic function of BAT, which generates heat by a process known as non-shivering thermogenesis [ 17 , 58 ]. This type of thermogenesis is extremely important in newborns both because their large area-to-volume ratio makes them more susceptible to heat loss and because their skeletal muscle tissue is not able to correctly maintain temperature through shivering [ 59 ].…”

Long-Term Pterostilbene Supplementation of a High-Fat Diet Increases Adiponectin Expression in the Subcutaneous White Adipose Tissue

“…Beige adipocytes express a set of specific genes, but also brown adipocyte-associated genes such as Ucp1, and have features in common with brown cells, such as abundant mitochondria. Physiological factors inducing browning are, for example, exposure to cold [13], physical exercise [14,15], or thyroid hormones [16,17]. Cold exposure leads to the release of norepinephrine by the sympathetic nervous system, which leads to activation of β3-adrenergic signalling; downstream signalling then branches and interacts with other pathways in complex patterns [18][19][20].…”