Laser speckle contrast imaging of hepatic microcirculation

The liver controls blood homeostasis and depends critically on adequate blood supply. While the global regulation of liver blood flow via the hepatic arterial buffer response is well established, the mechanisms governing hepatic sinusoidal hemodynamics remain elusive. We use laser speckle contrast imaging to investigate the hepatic microvascular blood flow in anesthetized rats. Laser speckle contrast imaging offers a spatial resolution of a few micrometers, enabling visualization of individual microvessels, and a temporal resolution sufficient to track flow dynamics. This allowed us to resolve individual sinusoids and venules on the liver surface and to detect a reduction of the blood flow following local Angiotensin II injections. We show that the microvascular blood flow oscillates with frequencies within the range of 0.05-0.4 Hz, which may be linked to rhythmic contraction of upstream blood vessels. Our findings provide insights into vessel-specific liver microcirculation in vivo, offering new opportunities to explore vascular dysfunction mechanisms in metabolic liver diseases.