Long-term effects of intrasplenically transplanted adult hepatocytes and fetal liver in hyperbilirubinemic Gunn rats

Abstract

We performed adult hepatocyte transplantation (HCTx) and fetal liver transplantation (FLTx) into the spleens of hyperbilirubinemic Gunn rats in congenic combination and we compared the long-term effects of these procedures for as long as 12 months. Proliferative activity of intrasplenic hepatocytes was evaluated using antiproliferating cell nuclear antigen (PCNA) immunohistochemical staining. The serum total bilirubin levels (T. Bil) significantly decreased from 7.16 +/- 0.25 mg/dl to 4.38 +/- 0.60 mg/dl 2 months after HCTx and gradually decreased thereafter until 12 months after transplantation (3.23 +/- 0.37 mg/dl, P < 0.05 vs preoperative value). The T. Bil change after FLTx was similar to that of HCTx: 7.22 +/- 0.24 mg/dl before FLTx, and 4.92 +/- 0.24 and 3.06 +/- 0.47 mg/dl, 2 and 12 months after FLTx (P < 0.05), respectively. Bilirubin glucuronides, which were not detectable in the bile from untreated Gunn rats, appeared in considerable amounts 4 months after HCTx and FLTx (27.5% and 36.0% of total bile, respectively). PCNA labeling indices of intrasplenic hepatocytes (4.9% +/- 0.9% and 3.7% +/- 0.7%, 6 months after HCTx and FLTx, respectively) were slightly higher than those of normal hepatocytes (1.0% +/- 0.1%) in the host liver. In conclusion, both adult and fetal rat hepatocytes transplanted into the spleen in congenic combination functioned for at least a year in terms of bilirubin glucuronidation. The spleen is considered to be one of the optimal grafting sites for hepatocytes, with nearly lifelong significant function and proliferative activity.

Functional Response of Hepatocytes Transplanted into Gunn Rats Stimulated with Thyroid Hormone

“…Although the use of adult cells has been studied in depth, there have been few reports on the effect of fetal liver transplantation. Fetal liver cells are highly regenerative and are known to grow and function for a long period after intrasplenic transplantation [13,14] as we have seen in our previous work [15]. Thus, in the present study, we performed fetal and adult intrasplenic hepatocyte transplantation in hyperbilirubinemic Gunn rats, bearing a defect in the bilirubin-UDP-glucuronosyl transferase gene, leading to accumulation of unconjugated bilirubin in the serum, similar to Crigler-Najjar type I syndrome in humans.…”

Human Hepatocyte Transplantation: Worldwide Results

“…In the Gunn rat model, a surrogate for human Crigler-Najjar Syndrome type 1 defect of bilirubin uridine diphosphate glucuronosyltransferase (bili UDPG transferase), 12% of the whole liver mass normalized bilirubin metabolism (41). KoKudo et al used normal, untreated, congenic rats (Wistar Shi) as sources of whole liver (for orthotopic liver transplantation [OLT]), or as donors of fetal or adult hepatocytes for transplant into Gunn rats, and studied bilirubin metabolism for 12 months (42). The intrasplenic transplanted fetal and adult congenic hepatocytes (10 7 cells, representing 2% liver mass) reduced total bilirubin by 30% at two months (compared to nl total bilirubin at two months with whole liver grafts), and at four months the hepatocytes expressed bilirubin glucuronide fractions 28 to 36% of total biliru- bin (compared to nl bilirubin glucuronide fractions with whole liver grafts at four months) (42).…”

“…KoKudo et al used normal, untreated, congenic rats (Wistar Shi) as sources of whole liver (for orthotopic liver transplantation [OLT]), or as donors of fetal or adult hepatocytes for transplant into Gunn rats, and studied bilirubin metabolism for 12 months (42). The intrasplenic transplanted fetal and adult congenic hepatocytes (10 7 cells, representing 2% liver mass) reduced total bilirubin by 30% at two months (compared to nl total bilirubin at two months with whole liver grafts), and at four months the hepatocytes expressed bilirubin glucuronide fractions 28 to 36% of total biliru- bin (compared to nl bilirubin glucuronide fractions with whole liver grafts at four months) (42). Colocalization studies of adenosine triphosphate and dipeptidyl peptidase IV (to illustrate gap junctions) of hepatocytes transplanted into the spleens of rats deficient in dipeptidyl peptidase IV, activity found that the transplanted hepatocytes rapidly overcame structural barriers, entered liver plates, and even formed chimeric bile canaliculi (43).…”

Hepatic proliferation in Gunn rats transplanted with hepatocytes: effect of retrorsine and tri‐iodothyronine

“…These improvements were noticed after foetal hepatocyte transplantation into RS-pre-treated Gunn rats (FHT-RS) two weeks after the treatment and lasted throughout the experimental period. Furthermore, after FHT the decrease in TSB is more remarkable from 3 months on after transplantation (Kokudo et al 1995a). When, T 3 was administered in RS-pre-treated animals both foetal and adult cells transplantation resulted in an improvement of TSB at all times of the study.…”

“…There have been several reports on the functionality of hepatocytes after transplantation in Gunn rats (Kokudo et al 1995a;Cubero et al 2001). These improvements were noticed after foetal hepatocyte transplantation into RS-pre-treated Gunn rats (FHT-RS) two weeks after the treatment and lasted throughout the experimental period.…”