Congenital Jaundice in Rats, Due to a Defect in Glucuronide Formation1

Schmid, Rudi; Axelrod, Julius; Hammaker, Lydia; Swarm, Richard L.

doi:10.1172/jci103702

Cited by 234 publications

(80 citation statements)

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“…Transplantation of hepatocytes by intrasplenic injection in Gunn rats has been shown to decrease serum bilirubin concentrations (8,23). However, bilirubin levels also decreased after intrasplenic injection of Gunn rat hepatocytes, suggesting that decrease in bilirubin levels might have been due to interference with splenic bilirubin production (9).…”

Section: Resultsmentioning

confidence: 99%

“…Transportation of hepatocytes (1)(2)(3), injection of hepatocyte extracts (1), and hepatocyte culture supernatants have been reported to prolong survival of rats with D(+)-galactosamine-induced liver injury (4) and animals with acute liver ischemia (5). Because homozygous Gunn rats lack UDP-glucuronosyltransferase activity for bilirubin, they cannot efficiently excrete bilirubin and, thus, exhibit lifelong nonhemolytic unconjugated hyperbilirubinemia (6)(7)(8). Hepatocyte transplantation has been used to impart the transferase activity in Gunn rats (9,10).…”

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confidence: 99%

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Survival, organization, and function of microcarrier-attached hepatocytes transplanted in rats.

Demetriou

Levenson

Novikoff

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

133

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Hepatocytes harvested by collagenase perfusion of rat liver were attached to collagen-coated microcarriers and injected intraperitoneally into congeneic or allogeneic bilirubin-UDP-glucuronosyltransferase (EC 2.4.1.17)-deficient (Gunn) rats or allogeneic analbuminemic (NAR) rats. Five days later, the microcarriers were observed to have formed conglomerates chiefly on the anterior surface of the pancreas. Scanning electron microscopy showed hepatocytes attached to the granular collagen-coated surface of the microcarriers and newly formed connective tissue. Light microscopy revealed that the microcarriers formed a lattice with the collagen tissue; hepatocytes were seen within this lattice or on the surface of the microcarriers. Hepatocyte plasma membranes were nucleoside-diphosphatase (NDPase)-positive. Newly formed blood islands, blood vessels containing erythrocytes and leukocytes and NDPase-positive endothelium were observed in close proximity to the hepatocytes and fibroblasts. Transmission electron microscopic examination showed hepatocytes with microvilli and nucleoid-containing peroxisomes with catalase activity. Hepatocytes were present for up to 2 months in congeneic recipients, the longest period of observation after transplantation. After normal microcarrierattached hepatocytes were transplanted into allogeneic Gunn rats, bilirubin glucuronides were present in bile for 6 days. When congeneic Gunn rat recipients were used, bilirubin glucuronides were present in bile throughout the study (28 days); this was accompanied by reduction of serum bilirubin concentrations to nearly normal levels. After injection of normal hepatocytes into allogeneic NAR rats, plasma albumin concentration progressively increased for 6 days and then declined. In NAR recipients which were immunosuppressed with cyclosporin A, peak plasma albumin levels were reached in 14 days and persisted nearly at that level throughout the study (28 days). We describe a technique in which isolated rat hepatocytes, attached to collagen-coated dextran microcarriers, were injected i.p. in homozygous Gunn rats and genetically analbuminemic (NAR) rats. The injected microcarrierattached hepatocytes form conglomerates in the peritoneal cavity. Light and electron microscopic examination of the conglomerates showed differentiated hepatocytes, newly formed blood vessels, and fibroblasts. Function of the transplanted hepatocytes was shown in Gunn rats by biliary excretion of conjugated bilirubin and reduction of serum bilirubin concentration and in NAR rats by the appearance of albumin in the plasma. MATERIALS AND METHODSMale Wistar rats (200-250 g) were purchased from Charles River Breeding Laboratories. Syngeneic Wistar (RHA) rats and congeneic Gunn rats, which have identical genetic make-up with the Wistar (RHA) rats except for the bilirubin conjugation locus, were developed by C. Hansen of the National Institutes of Health and maintained as congeneic strains at the Albert Einstein College of Medicine (Bronx, NY). Analbuminemic (NAR) rats, mutants...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Survival, organization, and function of microcarrier-attached hepatocytes transplanted in rats.

Demetriou

Levenson

Novikoff

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

133

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“…It is also possible that supersaturated solutions of B F can persist in plasma without aggregation and precipitation. 43 Indeed, there is little evidence that precipitates of bilirubin commonly exist in icteric plasma (or other aqueous tissues of the body; exceptions being the renal papillary tip of the Gunn rat, 44 infected bile or tissues of terminally ill patients with kernicterus 45 ). Even in Crigler-Najjar patients with very high bilirubin levels or homozygous Gunn rats there is no evidence of precipitation or aggregation of bilirubin in the circulation, observations that are consistent with circular dichroism studies on serum albumin-bilirubin binding by Lehner and colleagues 46 and their conclusion that 'even at pathophysiological total concentrations of bilirubin, the unbound portion does not exceed the solubility limit'.…”

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Calculated free bilirubin levels and neurotoxicity

2009

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Although most bilirubin in the circulation is bound to albumin, a relatively small fraction remains unbound. The concentration of this 'free' bilirubin (B F ) is believed to dictate the biologic effects of bilirubin in jaundiced newborns, including its neurotoxicity. The threshold at which B F produces changes in cellular function culminating in permanent cell injury and cell death has been the subject of considerable debate. The objective of this study was to compare calculated central nervous system (CNS) B F levels in Gunn rat pups during (i) peak postnatal hyperbilirubinemia and (ii) sulfadimethoxine-induced acute bilirubin encephalopathy (ABE) previously reported from our laboratory with those predicted in human neonates with peak total serum bilirubin (TSB) levels of 35 mg per 100 ml (599 mmol l À1 ), a clinical cohort that often evidence moderate-to-severe adverse post-icteric neurodevelopmental sequelae. Homozygous j/j Gunn rat pups with neonatal hyperbilirubinemia due to a deficiency of the bilirubin conjugating enzyme uridine-diphosphate-glucuronosyl transferase 1A1 were studied along with non-jaundiced littermate heterozygous J/j controls. Sulfadimethoxine was used to displace bilirubin from albumin in hyperbilirubinemic j/j Gunn rat pups to increase their brain bilirubin content and induce ABE. Calculated Gunn rat CNS B F levels were determined as a function of genotype, sulfadimethoxine exposure and albumin-bilirubin binding constant. These data were compared with the human CNS B F predicted from the calculated serum B F in human neonates with a TSB of 35 mg per 100 ml as a function of albumin-bilirubin binding constant, albumin concentration and the assumption that at this hazardous bilirubin level there may be rapid equilibration of B F between serum and brain. There was a large gap between the upper limit of the calculated CNS B F 95% confidence interval (CI) range in non-jaundiced J/j pups (for example, 112 nM at k ¼ 9.2 l mmol À1 ) and the lower limit seen in the saline-treated hyperbilirubinemic j/j pups (556 nM at k ¼ 9.2 l mmol À1 ) as well as between the upper limit in saline-treated hyperbilirubinemic j/j pups (1110 nM at k ¼ 9.2 l mmol À1 ) and the lower limit seen in sulfadimethoxine-treated jaundiced j/j littermates (3461 nM at k ¼ 9.2 l mmol À1 ). There was considerable overlap and remarkable similarity between the predicted human CNS B F values at a TSB of 35 mg per 100 ml for a range of reported human serum bilirubin-albumin binding constants and albumin concentrations, and those calculated for saline-treated hyperbilirubinemic j/j Gunn rat pups. This exercise yielded strikingly similar apparent calculated neurotoxic B F levels for Gunn rat pups and human neonates rather than orders of magnitude differences that might have been predicted at the outset and add to a growing literature aimed at defining clinically germane neurotoxic B F thresholds.

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“…The authors utilized the well-established Gunn rat model for CN disease, 2 which provides an attractive animal model to test gene therapy protocols for genetic diseases. CN disease type I is a rare inherited metabolic disorder caused by lack of the hepatic bilirubin uridine diphosho-glucuronosyltransferase (UGT1A1) activity, an enzyme which is responsible for the metabolic breakdown of bilirubin.…”

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confidence: 99%