Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023890 (cirrhosis)
 42,195 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Liver transplantation is the only effective treatment for hereditary tyrosinaemia type I (McKusick 276700). We have treated one acute and four subacute-chronic cases with 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC), a potent inhibitor of 4-hydroxyphenylpyruvate dioxygenase (EC 1.13.11.27), to prevent the formation of maleylacetoacetate and fumarylacetoacetate and their saturated derivatives. The oral daily dose was 0.1-0.6 mg/kg. The excretion of succinylacetoacetate and succinylacetone decreased from 15-103 mmol/mol creatinine to the detection limit or slightly above (ie, to 20-150 mumol/mol creatinine). The concentration of succinylacetone in plasma decreased from 5.8-43 mumol/l to the detection limit (0.1 mumol/l) over 2-5 months of treatment. The almost complete inhibition of porphobilinogen synthase in erythrocytes was abolished and the excretion of 5-aminolevulinate decreased to within or slightly above the reference range. The concentration of alpha-fetoprotein decreased in four patients to 1.3-7.5% of initially high values over 6-8 months. Improved liver function was reflected by normal concentrations of prothrombin complex and in decreased activities of alkaline phosphatase and gamma-glutamyltransferase in serum. Computed tomography revealed regression of hepatic abnormalities in three patients. One patient developed rickets 6 months before treatment and had excreted high concentrations of markers of tubular dysfunction--after 3 weeks of treatment, this excretion had disappeared. No side-effects were encountered. Inhibition of 4-hydroxyphenylpyruvate dioxygenase may prevent the development of liver cirrhosis and abolish or diminish the risk of liver cancer. Normalisation of porphyrin synthesis will eliminate the risk of porphyric crises. This type of treatment may thus offer an alternative to liver transplantation in hereditary tyrosinaemia.
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PMID:Treatment of hereditary tyrosinaemia type I by inhibition of 4-hydroxyphenylpyruvate dioxygenase. 135 48

Whereas ch/ch wild-type mice and ch/14CoS heterozygotes are viable, 14CoS/14CoS mice homozygous for a 3800 kb deletion on chromosome 7 die during the first day postpartum. Death is caused by disruption of the fumarylacetoacetate hydrolase (Fah) gene; absence of FAH, final enzyme in the tyrosine catabolism pathway, leads to accumulation of reactive electrophilic intermediates. In this study, we kept 14CoS/14CoS mice alive for 60 d with oral 2-(2-nitro-4-trifluoromethyl-benzyol)-1,3-cyclohexanedione (NTBC), an inhibitor of p-hydroxyphenylpyruvate dioxygenase, second enzyme in the tyrosine catabolic pathway. The 70% of NTBC-treated 14CoS/14CoS mice that survived 60 d showed poor growth and developed corneal opacities, compared with ch/14CoS littermates; NTBC-rescued Fah(-/-) knockout mice did not show growth retardation or ocular toxicity. NTBC-rescued 14CoS/14CoS mice also exhibited a striking oxidative stress response in liver and kidney, as measured by lower GSH levels and mRNA induction of four genes: glutamate cysteine ligase catalytic (Gclc) and modifier (Gclm) subunits, NAD(P)H:quinone oxidoreductase (Nqo1), and heme oxygenase-1 (Hmox1). Withdrawal of NTBC for 24-48 h from rescued adult 14CoS/14CoS mice resulted in severe apoptosis of the liver, detected histologically and by cytochrome c release from the mitochondria, increased caspase 3-like activity, and further decreases in GSH content. In kidney, proximal tubular epithelial cells were abnormal. Human hereditary tyrosinemia type I (HT1), caused by mutations in the FAH gene, is an autosomal recessive disorder in which the patient usually dies of liver fibrosis and cirrhosis during early childhood; NTBC treatment is known to prolong HT1 children's lives-although liver fibrosis, cirrhosis, hepatocarcinoma, and corneal opacities sometimes occur. The mouse data in the present study are consistent with the possibility that endogenous oxidative stress-induced apoptosis may be the underlying cause of liver pathology seen in NTBC-treated HT1 patients.
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PMID:Pharmacological rescue of the 14CoS/14CoS mouse: hepatocyte apoptosis is likely caused by endogenous oxidative stress. 1289 38

Hereditary tyrosinemia I (HT I) is a genetic disorder of tyrosine metabolism characterized by progressive liver damage from infancy and by a high risk for hepatocellular carcinoma. HT I is due to mutations in the fumarylacetoacetate hydrolase (Fah) gene, which encodes the last enzyme in the tyrosine catabolic pathway. Disturbances in tyrosine metabolism lead to increased levels of succinylacetone and succinylacetoacetate. However, the mechanisms causing liver failure, cirrhosis, renal tubular dysfunction, and hepatocarcinoma are still unknown. Lethal albino deletion c14CoS mice and mice with target-disrupted Fah are models for HT I. They die in the perinatal period, although with a different phenotype from that seen in HT I in humans. In addition, 2 mouse strains that carry N-ethyl-N-nitrosourea-induced mutations in the Fah gene have been described. Mice with a splice mutation exhibit the milder features of the clinical phenotype. In mice that carry both Fah and 4-hydroxyphenylpyruvate dioxygenase gene mutations, administration of homogentisate results in rapid apoptosis of hepatocytes. Simultaneously, renal tubular epithelial cells are injured, resulting in Fanconi syndrome. These are central features of visceral injury in patients with HT I. Apoptosis of hepatocyte and renal tubular cells is prevented by the caspase inhibitors acetyl-Tyr-Val-Ala-Asp-CHO or acetyl-Asp-Glu-Val-Asp-CHO. Apoptosis of hepatocytes and renal tubular epithelial cells are central features of this disease. Alterations in gene expression found in the liver of patients with HT I are responsible for the pathogenesis of this disease, for example, acute liver failure. Therefore, gene expression analysis allows a better understanding of the specific pathogenesis. Cell fusion of hematopoietic stem cells with hepatocytes leads to liver regeneration after liver injury. This finding was possible after using the liver injury model of HT I in Fah null mice. Thus, animal models of tyrosinemia are unique and useful tools to reveal mechanisms of interest to both clinical and basic science.
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PMID:Animal models of tyrosinemia. 1751 24