Subcutaneous adipose tissue blood flow varies between superior and inferior levels of the anterior abdominal wall

Abstract

Blood flow regulation is thought to mediate the metabolic functions of adipose tissue. Different depots, and even different layers within the subcutaneous adipose tissue, may vary in metabolic activity and blood flow. Therefore, we investigated if any differences in subcutaneous adipose tissue blood flow (ATBF) exist at different locations of the anterior abdominal wall. ATBF was measured 8-10 cm above or below the umbilicus, at 8-10 cm (both sides) from the midline, in 18 healthy subjects (BMI range 18-33 kg/m(2)). Measurements of ATBF were performed using (133)xenon washout, during a stable baseline period and after ingestion of 75 g of glucose. At baseline, ATBF was greater at the upper level compared to the lower level (4.4+/-0.3 vs 3.8+/-0.2 ml min(-1) 100 g tissue(-1), P=0.005), but was not different between the right and the left sides at either level. ATBF increased in response to oral glucose at all sites. The mean increase at the superior level was also greater than the inferior level (3.5+/-0.7 vs 2.2+/-0.6 ml min(-1) 100 g tissue(-1), P=0.001). Even at a constant depth and with only 16-20 cm difference between sites, there are significant differences in function of the same adipose depot. These findings have physiological and methodological implications for in vivo metabolic studies of human adipose tissue.