Via practica 4/2017

Current prospects in life-style and pharmacological control of adipose tissue morphological and functional characteristics in obese patients

White adipose tissue is an organ with an incredible ability to accumulate large amounts of energy in adipocytes. Depending on the energy availability, it produces specific spectra of biologically active substances (adipokines). These mediators could regulate food intake or tissue specific metabolic activity in order to support virtually all the energy demanding biological processes in our body. Brown adipose tissue, however, is a highly specialized thermogenic organ that utilizes energy of proton gradient on the inner mitochondrial membrane to generate heat. Brown fat also produces plenty of biologically active molecules (batokines) that are involved in regulating metabolic and redox balance. In small rodents, brown fat forms a functionally and morphologically distinct organ, with essential function in thermogenesis. In humans, we can sometimes find such defined tissue in a close proximity of large veins. But, much more often, we see brown fat cells scattered or intertwined within the white adipose tissue. Such tissue appears beige and its ability to regulate body temperature is not clear. However, we certainly know that metabolic activation of beige adipose tissue in humans increases energy expenditure and could be employed to alleviate negative metabolic consequences of obesity. Obesity is, however, associated with excessive lipid accumulation in adipose cells and when their storage capacity is exceeded, lipids are stored in brown adipocytes, hepatocytes or myocytes, limiting thus their normal physiological functions. Cold and physical activity induce adipose tissue browning (metabolic activation) via not yet completely known mechanisms, and directed activation of these processes could in fact have therapeutic potential for obese patients. However, current understanding of the thermogenic mechanisms is confounded by the great cellular heterogeneity as well as by the dynamics in regulation of the activity and cellular organization of brown/beige adipose tissue in humans.

Keywords: adipose tissue, thermogenesis, adaptive plasticity, physical activity, cold acclimation, obesity, metabolic health