Rochalimaea species stimulate human endothelial cell proliferation and migration in vitro

Rochalimaea henselae and R. quintana are associated clinically with proliferative neovascular lesions. The effect of Rochalimaea species on human umbilical vein endothelial cell (HUVEC) proliferation and migration was evaluated in vitro. Cocultivation of Rochalimaea organisms with HUVECs resulted in enhanced HUVEC proliferation. Fibroblast proliferation was unaffected by R. henselae. HUVECs were also stimulated to migrate by Rochalimaea. When R. henselae organisms were disrupted and subjected to centrifugation, the ability to enhance HUVEC proliferation and migration was localized to the particulate, noncytosolic fraction. Trypsin treatment of this fraction diminished its stimulatory activity. These data suggest that the neovascular manifestations of infection with Rochalimaea are likely caused by the production of an angiogenic factor by these bacteria.