Non-Invasive Estimation of Subcutaneous and Visceral Adipose Tissue Blood Flow by Using [15O]H2O PET with Image Derived Input Functions

Trained humans (Tr) have a higher fat oxidation during submaximal physical work than sedentary humans (Sed). To investigate whether this reflects a higher adipose tissue lipolytic sensitivity to catecholamines, we infused epinephrine (0.3 nmol.kg-1.min-1) for 65 min in six athletes and six sedentary young men. Glycerol was measured in arterial blood, and intercellular glycerol concentrations in abdominal subcutaneous adipose tissue were measured by microdialysis. Adipose tissue blood flow was measured by 133Xe-washout technique. From these measurements adipose tissue lipolysis was calculated. During epinephrine infusion intercellular glycerol concentrations were lower, but adipose tissue blood flow was higher in trained compared with sedentary subjects (P < 0.05). Glycerol output from subcutaneous tissue (Tr: 604 +/- 322 nmol.100 g-1.min-1; Sed: 689 +/- 203; mean +/- SD) as well as arterial glycerol concentrations (Tr: 129 +/- 36 microM; Sed: 119 +/- 56) did not differ between groups. It is concluded that in intact subcutaneous adipose tissue epinephrine-stimulated blood flow is enhanced, whereas lipolytic sensitivity to epinephrine is the same in trained compared with untrained subjects.

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Regional changes in adipose tissue blood flow and metabolism in rats after a meal

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1989.257.4.r711 ◽

1989 ◽

Vol 257 (4) ◽

pp. R711-R716 ◽

Cited By ~ 7

Author(s):

D. B. West ◽

W. A. Prinz ◽

M. R. Greenwood

Keyword(s):

Blood Flow ◽

Adipose Tissue ◽

Lipoprotein Lipase ◽

Lipase Activity ◽

Tissue Blood Flow ◽

Lipoprotein Lipase Activity ◽

Fat Depots ◽

Adipose Tissue Blood Flow ◽

Regional Specificity ◽

Adipose Tissue Lipoprotein Lipase

Adipose tissue blood flow was measured in five depots, and plasma concentrations of glucose, insulin, and triglyceride were measured at 0, 15, 30, and 45 min after the start of a meal in unanesthetized, freely moving rats. In addition, adipose tissue lipoprotein lipase activity was measured in four depots before and 45 min after the start of a meal. Plasma glucose was significantly elevated only at the 15-min time point, and while plasma triglyceride increased these changes did not reach significance. Plasma insulin was significantly elevated at all time points after a meal. Feeding resulted in a consistent decrease of adipose tissue blood flow expressed per gram wet weight of tissue. This decrease was maximal at 30 min after the start of feeding. The decrease in adipose tissue blood flow averaged 45% at 45 min after the start of feeding for the five depots evaluated. Lipoprotein lipase activity significantly increased in the retroperitoneal and mesenteric fat depots at 45 min after the meal start, but did not change in the epididymal or dorsal subcutaneous fat depots. These results suggest that a decrease in adipose tissue blood flow is a normal result of a meal in the rat. The regional specificity of changes in adipose tissue lipoprotein lipase activity supports the concept of regional specificity of function for adipose tissue and suggests that the mesenteric and retroperitoneal depots are particularly important for the storage of triglycerides immediately after a meal.

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Update on adipose tissue blood flow regulation

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00351.2011 ◽

2012 ◽

Vol 302 (10) ◽

pp. E1157-E1170 ◽

Cited By ~ 19

Author(s):

Richard Sotornik ◽

Pascal Brassard ◽

Elizabeth Martin ◽

Philippe Yale ◽

André C. Carpentier ◽

...

Keyword(s):

Blood Flow ◽

Adipose Tissue ◽

Proper Function ◽

Tissue Blood Flow ◽

Fat Tissue ◽

Physiological Conditions ◽

Current State ◽

Adipose Tissue Blood Flow ◽

Negative Impacts ◽

Arteriovenous Difference

According to Fick's principle, any metabolic or hormonal exchange through a given tissue depends on the product of the blood flow to that tissue and the arteriovenous difference. The proper function of adipose tissue relies on adequate adipose tissue blood flow (ATBF), which determines the influx and efflux of metabolites as well as regulatory endocrine signals. Adequate functioning of adipose tissue in intermediary metabolism requires finely tuned perfusion. Because metabolic and vascular processes are so tightly interconnected, any disruption in one will necessarily impact the other. Although altered ATBF is one consequence of expanding fat tissue, it may also aggravate the negative impacts of obesity on the body's metabolic milieu. This review attempts to summarize the current state of knowledge on adipose tissue vascular bed behavior under physiological conditions and the various factors that contribute to its regulation as well as the possible participation of altered ATBF in the pathophysiology of metabolic syndrome.

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