STED microscopy: A simplified method for liver sinusoidal endothelial fenestrae analysis.

BACKGROUND INFORMATION: Liver sinusoidal endothelial cells (LSECs) possess fenestrae, open transcellular pores with an average diameter of 100 nm. These fenestrae allow for the exchange between blood and hepatocytes. Alterations in their number or diameter in liver diseases have important implications for hepatic microcirculation and function. Although decades of studies, fenestrae are still observed into fixed cells and we have poor knowledge of their dynamics. RESULTS: Using stimulated emission depletion (STED) super-resolution microscopy, we have established a faster and simplest method to observe and quantify fenestrae. Indeed, using cytochalasin D, an actin depolymerising agent known to promote fenestrae formation, we measure the increase of fenestrae number. We adapted this methodology to develop an automated method to study fenestrae dynamics. Moreover, with two-colour STED analysis, we have shown that this approach could be useful to study LSECs fenestrae molecular composition. CONCLUSIONS: Our approach demonstrates that STED microscopy is suitable for LSEC fenestrae study. SIGNIFICANCE: This new way of analysing LSEC fenestrae will allow for expedited investigation of their dynamics, molecular composition and functions to better understand their function in liver pathophysiology.