Obesity and Fat Cellularity
Obesity is the storage of excess fat and can be classified by the number and size of fat cells. Fat cells increase in size as the amount of lipids in the cells increase via lipogenesis/lipid uptake, whereas lipolysis decreases fat cell size through lipid mobilization. There are physical limits on how much lipid can be stored by an adipocyte (how large a fat cell can become), but there appears to be no limit on the number of fat cells and as such, increases in fat cell number (adipocyte hyperplasia) is the hallmark of obesity. Activation of the SNS innervation of white adipose tissue not only increases lipolysis, but it also inhibits preadipocyte proliferation, two conditions that promote obesity reversal. How the SNS inhibits fat cell proliferation is also being researched and could lead to potential therapeutic approaches to inhibit fat cell proliferation, thereby potentially limiting the degree of obesity.