Hepatocyte Transplantation / 대한이식학회지

Since the first hepatocyte transplantation (HT) was done by Matas and colleagues 3 decades ago in Gunn rats, there has been much development in the field of HT and clinical application to over 70 humans has been performed worldwide ever since. HT has many advantages compared to the conventional liver transplantation (LT) such as lower cost, lower morbidity, possibility of genetic modification, availability of cryopreservation, utilization of inadequate livers for LT and possibility to transplant to multiple recipients from a single donor. HT has been applied as a definitive treatment option in metabolic liver disease or fulminant hepatic failure with marginal results. It has also been used as a bridge to LT in severely ill patients awaiting LT, but it has not yet been widely accepted due to the shortcoming of clinical efficacy compared to LT. Much effort was made over the past several years to improve these results, and we hope that with the help of future research, HT will soon have a clear clinical role in the management of liver diseases. This review article will cover various animal models used for researching HT and methods used for transplanting hepatocytes. It will also briefly introduce the worldwide clinical results in human trials as well as our experience on a successful case with glycogen storage disease and its long term result.

The effect of cotransplantation of nonparenchymal liver cells on the survival of intraperitoneally transplanted hepatocytes / 대한내과학회지

BACKGROUND: Transplantation of primary hepatocytes (PH) has been shown to provide metabolic support during acute liver failure. However, PH are known to be subject to necrosis in the peritoneal cavity. This is because cell-cell interaction plays an important role in their survival, but the peritoneal cavity can not provide such an environment. We tried to improve the survival of PH by simultaneously transplanting nonparenchymal liver cells (NPL). METHODS: PH from normal Wistar rats, either alone (10(9) cells/kg, group 1, n=10) or mixed with NPL (5x10(8) cells/kg, group 2, n=10) were transplanted into the peritoneal cavity of hyperbilirubinemic Gunn rats which are congenitally devoid of bilirubin glucuronidation. Liver cells from Gunn rats were transplanted as a control. RESULTS: Bilirubin glucuronides (BG) were detected in the bile of both group 1 and 2 rats collected at 6 hours after transplantation, and reached peak levels in 4 days. However, in the third and fourth week, BG could be detected only in group 2 animals. The serum bilirubin levels were decreased by 12.1~18.9% of basal levels in the second and third week for group 2 rats, but decreased by 15.1% only in the second week for the group 1 rats. Using in situ hybridization, albumin mRNA positive cells could be detected until the fourth week for the group 2 animals, but only until the second week for the group 1 rats. CONCLUSIONS: PH start functioning in a short time after intraperitoneal transplantation and simultaneous transplantation of NPL with PH can prolong the survival and function of transplanted hepatocytes.

In vitro and in vivo Efficacy of New Blue Light Emitting Diode Phototherapy Compared to Conventional Halogen Quartz Phototherapy for Neonatal Jaundice

High intensity light emitting diodes (LEDs) are being studied as possible light sources for the phototherapy of neonatal jaundice, as they can emit high intensity light of narrow wavelength band in the blue region of the visible light spectrum corresponding to the spectrum of maximal bilirubin absorption. We developed a prototype blue gallium nitride LED phototherapy unit with high intensity, and compared its efficacy to commercially used halogen quartz phototherapy device by measuring both in vitro and in vivo bilirubin photodegradation. The prototype device with two focused arrays, each with 500 blue LEDs, generated greater irradiance than the conventional device tested. The LED device showed a significantly higher efficacy of bilirubin photodegradation than the conventional phototherapy in both in vitro experiment using microhematocrit tubes (44 +/-7% vs. 35 +/-2%) and in vivo experiment using Gunn rats (30 +/-9% vs. 16 +/-8%). We conclude that high intensity blue LED device was much more effective than conventional phototherapy of both in vitro and in vivo bilirubin photodegradation. Further studies will be necessary to prove its clinical efficacy.

The Association of Neonatal Hyperbilirubinemia with UGT1A1 and CYP1A2 Gene Polymorphism in Korean Neonates / 소아과

PURPOSE: The incidence of nonphysiologic neonatal hyperbilirubinemia is twice as high in East Asians as in whites. Recently, UGT1A1 mutation was found to be a risk factor for neonatal hyperbilirubinemia. In congenitally-jaundiced Gunn rats, which lack expression of UDP-glucuronosyltransferase, alternative pathways can be stimulated by inducers of CYP1A1 and CYP1A2 enzymes. CYP1A2 plays a major role in bilirubin degradation of the alternate pathway. We studied the relationship between UGT1A1 and CYP1A2 gene polymorphism of neonatal hyperbilirubinemia in Koreans. METHODS: Seventy-nine Korean full term neonates who had hyperbilirubinemia(serum bilirubin >12 mg/dL) without obvious causes of jaundice, were analyzed for UGT1A1 and CYP1A2 gene polymorphism; the control group was sixty-eight. We detected the polymorphism of Gly71Arg of UGT1A1 gene by direct sequencing and T2698G of CYP1A2 by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) using MboII and direct sequencing. RESULTS: Allele frequency of Gly71Arg mutation in the hyperbilirubinemia group was 32 percent, which was significantly higher than 11 percent in the control group(P<0.0001). Mutant gene frequency of T2698G was 41.8 percent in patients and 32.3 percent in the control group(P=0.015), but allele frequency was 21 percent in patients and 19 percent in the control group, which was not significantly higher(P=0.706). There was no relationship between mutations of two genes(P=0.635). CONCLUSION: The polymorphism of UGT1A1 gene(Gly71Arg) and CYP1A2 gene(T2698G) was detected in Korean neonatal hyperbilirubinemia. Only polymorphisms of Gly71Arg in UGT1A1 were significantly higher than control group.

Evaluation of the Bilirubin Ototoxicity using ABR and DPOAE in Jaundiced Gunn Rats / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: In neonatal hyperbilirubinemia, accumulation of unconjugated bilirubin in the central auditory pathway and basal ganglia may cause sensorineural hearing loss and neurologic sequelae. The effect of unconjugated bilirubin on the brain is known well through auditory brainstem responses (ABRs). However, there is no evidence of pathologic changes in the cochlea. Jaundiced (jj) Gunn rats have been used as a good animal model for hyperbilirubinemia-related auditory dysfunction. The purpose of this study is to evaluate the bilirubin ototoxicity using ABR and DPOAE in jaundiced Gunn rats before and after sulfadimethoxine injection. MATERIALS AND METHOD: Experiments were conducted on three homozygous (jj) P19 (postnatal 19 days) littermates, one heterozygous Gunn rat, five P21 jj littermates, and one nj Gunn rat littermate. P21 jj and nj Gunn rats were re-tested in three weeks in the same condition. ABR with 100-microsecond pulse width click and DPOAEs at 8 kHz, 16 kHz and 22 kHz were measured before and after 1 mg/kg sulfadimethoxine injection. RESULTS: The thresholds of ABR were elevated in P19 and P21 group within the first day after injection and became normalized at several days after injection. Delay of wave II, III, IV and V were also observed. DPOAE showed no significant change after injection in all groups, meaning that the cochlea was not damaged. CONCLUSION: This study shows that bilirubin ototoxicity is related with pathologic changes at or higher than the brainstem level with intact cochlear function. Changes in ABR findings were only observed in P19 and P21 groups because they had higher bilirubin level in blood and their central auditory pathway is more immature than that found in the P42 group. In this study, we also found the possibility of spontaneous recovery from hyperbilirubinemia-related auditory toxicity.