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

Microvascular perfusion in skeletal muscle (SkM) and subcutaneous adipose tissue (AT) is critical for insulin-mediated glucose uptake and is impaired in type 2 diabetes (T2D). Quantifying perfusion using contrast enhanced ultrasound (CEU) is technically challenging, prompting a need for simpler methods such as laser Doppler flowmetry (LDF). This study evaluated the relationship between LDF-derived and CEU-derived perfusion measures in SkM and subcutaneous AT of control and T2D nonhuman primates. Fourteen cynomolgus macaques (control n = 6; T2D = 8) underwent simultaneous CEU and LDF measurements at baseline and post-intravenous dextrose (300 mg/kg). CEU-derived perfusion and LDF-derived perfusion were compared across conditions in SkM and subcutaneous AT. In SkM, CEU-derived perfusion doubled post-dextrose in controls whereas this response was attenuated in T2D animals. In subcutaneous AT, CEU-derived perfusion increased post-dextrose in T2D animals. LDF did not detect significant post-dextrose changes in either tissue. There was no correlation between absolute CEU- and LDF-derived perfusion at baseline; however, the percent change in SkM perfusion was positively correlated between methods. These findings suggest that LDF should not be considered interchangeable with CEU for quantifying tissue microvascular perfusion but may provide complementary information about relative changes in SkM perfusion when an intervention is applied to alter hemodynamics.