The resident hepatic macrophage, the Kupffer cell, has many important roles in health maintainance and injury. In the the histologic specimen above, the Kupffer cells are stained dark brown. They line the hepatic sinusoids.
Historically, this macrophage’s role lied in phagocytic clearance of infections, tissue development and wound repair. However, it is far more functionally complex. In addition, they regulate hematopoiesis, vasoregulation, apoptosis, cancer metastasis and lipid metabolism. They also stimulate lymphocyte production of interleukins and TNF (inflammation).