Dynamics of Human Adipose Tissue. Regulatory Mechanisms and Consequences for Fat Cells and the Whole Body

Abstract

Human adipose tissue was previously considered to be a rather inert tissue in adult life, with no or little ongoing adipogenesis (generation of new fat cells). We recently developed a method to measure the age of fat cells. By using this technique, we established a very high turnover rate of fat cells in adult life. About 10% of the cells are renewed every year due to the constant adipogenesis and cell death that occur throughout the adult life span. The number of fat cells turned over each year is increased among the obese, and adipocyte turnover also influences the cellularity of adipose tissue. If obesity is present or not, those who have few but large fat cells (hypertrophy) have a lower turnover of fat cells than those with many small fat cells (adipose hyperplasia). The different forms of cellularity have clinical consequences; hypertrophy is associated with an adverse metabolic profile in large population-based samples. Thus, adipocyte turnover is important for the development of obesity and for the metabolic profile.