Subcutaneous fat in normal and diseased states

In recent years, our understanding of adipose tissue physiology and function has undergone an enormous transformation. Once considered a passive storage receptacle with a fixed number of cells and limited purpose, adipose tissue is now recognized as a complicated organ with important endocrine and metabolic functions. It is now known that both increased and decreased adipose tissue mass, as seen in obesity, anorexia, and lipodystrophy, have profound effects on multiple body systems, including immune, reproductive, and hematopoietic. The study of adipose tissue, therefore, is important not only for those who treat obesity, lipoatrophy, and their associated metabolic and endocrine derangements, but also for those dermatologists who specialize in the medical and surgical treatment of disorders within the body's largest adipose tissue subdivision, the subcutaneous fat. This introductory article is the first in a series about adipose tissue in normal and diseased states.