Hemodynamic and metabolic correlates in adipose tissue: pathophysiologic considerations

Research efforts investigating the pathophysiology of adipose tissue have often focused separately on either the metabolic or cardiovascular components of an expanding fat mass. However, the growth and development of the fat cells and their vasculature are closely interrelated, a fact that has been established through more than a century of diverse studies of adipose tissue. Recently, the prevalence of obesity in the United States has stimulated investigations into the cardiovascular and metabolic correlates occurring with excessive lipid deposition and subsequent adipose tissue expansion. These investigations have resulted in conclusive evidence that, from a cardiovascular perspective, obesity results in an elevated blood volume and cardiac output, accompanied by an expansion of adipose water space, whereas from a metabolic aspect, the disease is characterized by adipocyte enlargement and associated alterations in metabolic pathways and hormonal responsiveness. Because these separate areas of research have independently shown interdepot differences in perfusion requirements and metabolic adaptations during the transition from the lean to obese state, adipocyte expansion may be partially dependent on the pattern of vascularity. This hypothesis is discussed by examining the integral relationship between the cardiovascular system and adipocyte metabolism, hopefully providing new insight into control of the pathophysiological processes of an expanding adipose organ.