Kettle - Autonomic and central nervous system regulation of metabolism
Our lab examines the underlying neurobiology and neurochemistry that underlies the physiology of metabolism. In 2009 our understanding of metabolism in humans was transformed by the discovery that a significant amount of brown adipose tissue is found in adult humans. Brown adipose tissue is important as it is specialized for wasting stored energy (body fat) as heat. There is an inverse correlation between the amount of brown adipose tissue a person has and the likelihood of the development of obesity. Further, activation of brown adipose has been shown to have positive effects on glucose sensitivity (i.e. an anti-diabetic effect).
Brown adipose tissue activation has also been implicated in cancer cachexia and stress and anxiety, suggesting that understanding the regulatory mechanism that underlies brown adipose tissue has significant impact on the health care of individuals with these conditions.
We are currently developing techniques for measuring brown adipose tissue activity in humans to complement our basic research.
Research areas
Use of thermal imaging to measure brown adipose tissue activation in adult humans
Until recently, brown adipose tissue was thought to be insignificant in the physiology of adult humans. Brown adipose tissue is involved in body temperature regulation, and although it was found to be prevalent in infants, it was thought to only be present in adults in negligible quantity. Using radiolabeled glucose and PET imaging, it has now been confirmed that brown adipose tissue is present in adults. PET imaging to measure radiolabeled glucose usage in tissue remains the gold standard measurement of brown adipose tissue activation in humans. However, PET imaging studies are expensive, and the use of ionizing radiation make these types of studies difficult to conduct.
Although thermal imaging has been used to measure changes in skin temperature to indicate brown adipose tissue thermogenesis, the technique is not broadly accepted as a valid and reliable approach. We have been working using indirect calorimetry in parallel with thermal imaging to measure brown adipose tissue thermogenesis.
The central nervous system control of metabolically evoked brown adipose tissue thermogenesis
Brown adipose tissue (BAT) thermogenesis is tissue specialized for using circulating free fatty acids in the body, and wasting that stored energy as heat. Historically, BAT thermogenesis has been investigated for its role in body temperature regulation and fever response. More recently, however, BAT has been implicated in the regulation of body weight.
Our research is focused on identifying specific neural pathways within the CNS that regulate BAT thermogenesis. Crucially, we are interested in understanding the neurotransmitter systems that control BAT activity in the hope of identifying potential drug targets for exogenous regulation of BAT.
