New research shows that ‘brown fat’, the body’s own fat-fighting defences, can be mobilised by different physiological factors, and could be used help to tackle obesity.
Being overweight or obese is a major health risk, as shown in the greatly increased prospect of a worse outcome when suffering from COVID-19.
Fat in the human body is composed by three types of cells defined as white, beige or brown.
White fat stores energy, whilst brown – or good – fat produces heat by burning sugar and fat, often in response to cold. Increasing its activity improves blood sugar control as well as improving blood lipid levels and the extra calories burnt help with weight loss.
People with a lower body mass index (BMI) have a higher amount of brown fat.
Beige fat cells are located within white fat depots and can be induced into ‘burning energy’, as brown cells typically do. They are abundant in humans and could so be targeted for obesity management.
Two new studies from the groups of Professors Mike Symonds from the School of Medicine at the University of Nottingham and Virginie Sottile from the University of Pavia, Italy, have used stem cells to model how brown fat can be mobilised by physiological factors.
The first collaborative study, led by Dr Lugo Leija, from the Medical Technologies Innovation Facility in Nottingham, and published in the Journal of Cellular and Molecular Medicine, shows how fat cells produced from stem cells and stimulated under cold conditions, can remain metabolically active even once they have returned to warmer conditions.
These results suggest that the rapid adaptation occurring in fat cells in response to environmental changes, such as exposure to cold conditions, and typically associated with a favourable effect on metabolism, is partly retained over time.
This research could help design new treatments to control fat tissue characteristics in order to promote energy expenditure in obese patients -your total daily energy expenditure (TDEE) is the number of calories you burn each day.
In a second study led by Dr Ksenija Velickovic, from the University of Belgrade, and published in the journal Cellular Metabolism & Biochemistry, the team further showed for the first time that a small drug which inhibits glutamine synthesis, can prevent stem cells from becoming fat cells.
Blocking glutamine metabolism limited the formation of lipid droplets and changed the characteristics of the fat cells produced, suggesting that glutamine represents an important component of the cellular machinery leading to the accumulation of fat.
The collaborative team, involving researchers from the University of Nottingham’s School of Medicine, the University of Los Angeles and the Department of Molecular Medicine of the University of Pavia, will continue their work look to uncover how selective interference with glutamine metabolism in stem cells, normally destined to form fat cells, could be used to better control weight and improve health.