Table 1.

Differences in the hepatocyte growth factor (HGF) supply system after tissue injury between epithelial organs and the spinal cord. Compared to epithelial organs, including the liver, lung, and kidney, the injured spinal cord has a poor ability to upregulate endogenous HGF, nor does it receive HGF supplied from other organs.

Epithelial Organs (Liver, Lung, or Kidney)		Spinal Cord
Marked increase within 24 h after injury	Endogenous upregulation of HGF in the injured organ	Weak and delayed, with a peak around 4 weeks after injury
Marked increase within 24 h after injury	Delivery of HGF from other intact organs via an endocrine mechanism	No delivery