Contrast enhanced ultrasound and laser doppler flowmetry capture distinct aspects of tissue microvascular perfusion in nonhuman primates

Figures

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  FIGURE 1. Experimental timeline and schematic of ultrasound and laser doppler probe placement and outputs Animals were fasted 12 h prior to procedure. Following sedation, intubation and anesthesia, Laser Doppler flow (LDF) probes (shown in green) were placed simultaneously in subcutaneous adipose tissue (AT) and skeletal muscle (SkM) to continuously record blood perfusion units (BPU) throughout. Contrast enhanced ultrasound (CEU) imaging was performed in subcutaneous AT and SkM sequentially at baseline (shown in pink) and 10 min post‐dextrose bolus (300 mg/kg; shown in blue). Post hoc CEU analysis involved selecting regions of interest to calculate microvascular perfusion, microvascular volume and microvascular flow velocity in subcutaneous AT and SkM.

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  FIGURE 2. Dextrose administration increases plasma insulin in control animals but not T2D animals. (a) Plasma glucose and (b) plasma insulin concentration were measured at baseline (BL) and 10 min post‐dextrose bolus (Post) in control and T2D animals. Data is shown as mean ± SE.

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  FIGURE 3. Percent change in SkM perfusion measured by CEU and LDF was correlated, although LDF‐derived perfusion did not independently detect insulin‐stimulated SkM hyperemia in control animals. SkM perfusion was measured by (a) CEU and (b) LDF at baseline (BL) and post‐dextrose administration in (Post) control and T2D animals. (c) Time matched CEU and LDF data values were converted to percent change from baseline to undergo Pearson correlation analysis (results shown). Data is shown as mean ± SE (A and B) or percent change from baseline (C).

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  FIGURE 4. There was no correlation between CEU‐ and LDF‐derived perfusion measures in subcutaneous AT. Subcutaneous AT perfusion was measured by (a) CEU and (b) LDF at baseline (BL) and post‐dextrose administration (Post) in control and T2D animals. (c) Time matched CEU and LDF data values were converted to percent change from baseline to undergo Pearson correlation analysis (results shown). Data is shown as mean ± SE (A and B) or percent change from baseline (C).