Immunohistochemical studies on the innervation of human transplanted liver.

The changing pattern of innervation in the human transplanted liver was studied from the day of transplantation to 5 years later. Seven liver biopsies from non-transplant controls, 37 liver biopsies from 22 transplant patients, and one of these biopsied livers removed at retransplantation, were available for the study. Sections were immunostained for protein gene product 9.5 (PGP 9.5), neurone-specific enolase (NSE), S-100 protein, and vasoactive intestinal polypeptide. NSE and PGP 9.5 demonstrated nerves most successfully in our tissues. Staining for most small nerves was reduced by day 5 post-transplantation. Scanty fine nerves could be detected from day 13 to day 241 in occasional biopsies. Consistently identifiable immunostaining of PGP 9.5 and NSE nerve fibres was again apparent in portal areas after this time in all but one case. The findings indicate that in transplanted liver limited reinnervation can eventually take place. This could be due to either proliferation of intrinsic nerves, or regrowth of extrinsic nerves, or both.