Identification of human brown/beige adipose tissue using near-infrared time-resolved spectroscopy

摘要

Brown/beige adipose tissue (BAT) is expected to contribute to protecting lifestyle-related diseases. The purpose of thisstudy was to examine if near-infrared time-resolved spectroscopy (NIRTRS) is capable of distinguishing BAT frommuscle and white adipose tissue (WAT). We analyzed the optical characteristics of tissues in the supraclavicular region,where BAT deposits can be located, and deltoid and abdominal regions in 36 participants (16 men and 20 women) whowere apparently healthy individuals, with a median age of 44.5 years, in winter and summer. They also had a medianbody fat percentage of 28.3% and a deltoid and abdominal adipose tissue thickness of 0.85 cm and 1.71 cm, respectively.The total hemoglobin concentration [total-Hb] and the reduced scattering coefficient (μs′) were determined using nearinfraredtime-resolved spectroscopy (NIRTRS) with a 3 cm optode separation for supraclavicular and deltoid regions and a2 cm optode separation for abdominal region. The results regarding data collected in winter were the following: deltoid(μs￠? = 9.6 [9.1, 10.4] cm~（-1）, [total-Hb] = 114.9 [107.0, 127.7] μM); abdominal (μs￠? = 9.0 [7.9, 10.1] cm~（-1）, [total-Hb] = 11.2[8.0, 16.0] μM); and supraclavicular (μs￠? = 7.9 [7.2, 8.7] cm~（-1）, [total-Hb] = 60.7 [48.9, 74.7] μM)) in winter. Some dataare overlapped between groups of muscle and BAT. These results indicated that [total-Hb] and μs′ show region-specificcharacteristics. We conclude that using [total-Hb] - μs′ relationship determined by NIRTRS is a useful strategy todistinguish BAT from other tissues in a simple, rapid, and non-invasive manner.