How are spleen sinusoids?

• The sinus-lining cells, also called littoral cells (specialized endothelial cells), have overlapping cytoplasmic processes without tight junctions. • Sinusoids are surrounded by distinctive ring fibers. • The littoral cells, which literally means “shoreline” or “tidal”, comprise 30% of the red pulp and are phenotypically distinct from endothelial cells in other tissues, including those with sinusoidal compartments.