UMLS:C0023890 - FACTA Search

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)

Successful liver transplantation in a child is often a hard-won victory, requiring all the combined expertise of a dedicated pediatric transplant team. This article outlines the considerable challenges still facing pediatric liver transplant physicians and surgeons. In looking to the future, where should priorities lie to enhance the success already achieved? First, solutions to the donor shortage must be sought aggressively by increasing the use of from split-liver transplants, judicious application of living-donor programs, and increasing the donation rate, perhaps by innovative means. The major immunologic barriers, to successful xenotransplantation make it unlikely that this option will be tenable in the near future. Second, current immunosuppression is nonspecific, toxic, and unable to be individually adjusted to the patient's immune response. The goal of achieving donor-specific tolerance will require new consideration of induction protocols. Developing a clinically applicable method to measure the recipient's immunoreactivity is of paramount importance, for future studies of new immunosuppressive strategies and to address the immediate concern of long-term over-immunosuppression. The inclusion of pediatric patients in new protocols will require the ongoing insistence of pediatric transplant investigators. Third, the current immunosuppressive drugs have a long-term morbidity and mortality of their own. These long-term effects are particularly important in children who may well have decades of exposure to these therapies. There is now some understanding of their long-term renal toxicity and the risk of malignancy. New drugs may obviate renal toxicity, whereas the risk of malignancy is inherent in any nonspecific immunosuppressive regimen. Although progress is being made in preventing and recognizing PTLD, this entity remains an important ongoing concern. The global effect of long-term immunosuppression on the child's growth, development, and intellectual potential is unknown. Of particular concern is the potential for neurotoxicity from the calcineurin inhibitors. Fourth, recurrent disease and new diseases, perhaps potentiated by immunosuppressive drugs, must be considered. Already the recurrence of autoimmune disease and cryptogenic cirrhosis have been documented in pediatric patients. Now, a new lesion, a nonspecific hepatitis, sometimes with positive autoimmune markers, that may progress to cirrhosis has been recognized. It is not known whether this entity is an unusual form of rejection, an unrecognized viral infection, or a response to immunosuppressive drugs themselves. Finally, pediatric transplant recipients, like any other children, must be protected and nourished physically and mentally if they are to fulfill their potential. After liver transplantation the child's growth, intellectual functioning, and psychologic adaptation may all require special attention from parents, teachers, and physicians alike. There is limited understanding of how the enormous physical intervention of a liver transplantation affects a child's cognitive and psychologic function as the child progresses through life. The persons caring for these children have the difficult responsibility of providing services to evaluate these essential measures of children's health over the long term and to intervene if necessary. Part of the transplant physician's our duty to protect and advocate for children is to fight for equal access to health care. In most of the developing world, economic pressures make it impossible to consider liver transplantation a health care priority. In the United States and in other countries with the medical infrastructure to support liver transplantation, however, health care professionals must strive to be sure that the policies governing candidacy for transplantation and allocation of organs are applied justly and uniformly to all children whose lives are threatened by liver disease. In the current regulatory climate that increasingly takes medical decisions out of the hands of physicians, pediatricians must be even more prepared to protect the unique and often complicated needs of children both before and after transplantation. Only in this way can the challenges of the present and the future be met.
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PMID:Liver transplantation. The pediatric challenge. 1123 62

Hepatic graft rejection is a common complication after liver transplantation (LT), with a maximum incidence within the first weeks. The identification of high-risk patients for early acute rejection (EAR) might be useful for clinicians. A series of 133 liver graft recipients treated with calcineurin inhibitors was retrospectively assessed to identify predisposing factors for EAR and develop a mathematical model to predict the individual risk of each patient. The incidence of EAR (< or =45 days after LT) was 35.3%. Multivariate analysis showed that recipient age, underlying liver disease, and Child's class before LT were independently associated with the development of EAR. Combining these 3 variables, the following risk score for the development of EAR was obtained: EAR score [F(x)] = 2.44 + (1.14 x hepatitis C virus cirrhosis) + (2.78 x immunologic cirrhosis) + (2.51 x metabolic cirrhosis)--(0.08 x recipient age in years) + (1.65 x Child's class A) [corrected]. Risk for rejection = e(F(x))/1 + e(F(x)). The combination of age, cause of liver disease, and Child's class may allow us to predict the risk for EAR.
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PMID:Prognostic model for early acute rejection after liver transplantation. 1124 67

During the last two decades, owing to advances in immunosuppressive pharmacotherapy, liver transplantation has been increasingly accepted by the medical community as an effective treatment for patients with end-stage liver disease. Successful transplantation of the liver, however, requires frequent monitoring. Most of the serious infectious complications and allograft dysfunction occur during the early post-transplantation period (i.e., first six months). Blood levels of cyclosporine or tacrolimus, the two major calcineurin inhibitors currently in use, need to be frequently checked. Drug dosage is adjusted in order to maintain target serum concentrations and the patients free of side-effects. In the time, the risk of acute allograft rejection decreases considerably, whereas the proportion of patients with fibrosis or cirrhosis increases, particularly among hepatitis C virus carriers. Graft loss may occur, secondary to recurrent disease or chronic rejection. Patients with well-functioning grafts may still be affected by significant comorbidities, such as hypertension, diabetes, obesity, hyperlipidemia and osteoporosis, which appear to be related to long-term immunosuppression. The incidence of lymphoma, skin and colorectal cancers in liver transplantation recipients exceeds those found in the general population and requires early detection. The principles of the management of medical problems after liver transplantation are a careful clinical assessment of the patient and a judicious use of laboratory tests, radiological evaluation and liver biopsy.
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PMID:[Periodic clinical monitoring after liver transplantation]. 1141 96

Hepatitis C virus (HCV)-induced cirrhosis is the commonest indication for orthotopic liver transplantation, but HCV recurrence is nearly universal and may worsen patient / graft outcomes. The frequency and severity of HCV recurrence has apparently increased in recent years, raising concern about a possible role for newer immunosuppression regimens in this increase, including potentially tacrolimus. We randomized 79 patients to receive tacrolimus or cyclosporine as primary immunosuppressant posttransplantation. A pathologist blinded to treatment reviewed serial liver biopsies. Month 12 cumulative probabilities of histological hepatitis C recurrence for tacrolimus- and cyclosporine-treated patients were .38 and .54 (P = .19) and failure / death were .25 and .28, respectively (P = .789). Although cyclosporine-treated patients had significantly larger increases in median serum HCV RNA levels (months 1, 6, and 12), no significant differences were observed between the two treatment arms in histologically-diagnosed HCV recurrence / survival rates. In conclusion, choice of calcineurin inhibitors does not impact severity of recurrent HCV.
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PMID:Impact of tacrolimus versus cyclosporine in hepatitis C virus-infected liver transplant recipients on recurrent hepatitis: a prospective, randomized trial. 1537 10

Little is known about hearing impairment in patients after organ transplantation. Few cases of hearing loss associated with different immunosuppressants have been published. To evaluate severe hearing impairment in patients after liver transplantation (OLT), all living adult patients in need of a hearing aid were analyzed. Out of 521 transplanted patients, 25 (5%) were identified with hearing aids. Nine (36%) of these patients either suffered from hearing loss prior to OLT or experienced risk factors such as ototoxic drugs. Of the remaining 16 patients who developed severe hearing loss after OLT (64%), half were men. Mean age was 42 +/- 18 years at OLT, which took place 8 +/- 4 years ago. Main transplantation indication was virus-induced cirrhosis (44%). In 14/16 (88%) patients, the hearing aid was bilateral. In 50% of patients, the hearing aid was necessary within 2 years post-OLT. Additional tinnitus was present in 9/16 patients (56%), otalgia in three patients (19%). Four patients (25%) reported a history of sudden deafness. In three of them, an association with high levels of calcineurin inhibitors was found. The proportion of patients receiving tacrolimus (50%) was relatively higher than those receiving cyclosporine (50%) compared to control patients (28% respectively 64%, P < .05). In conclusion, a high incidence of severe hearing loss was found in patients after liver transplantation. In most patients, onset of hearing loss is early and bilateral, suggesting a dose-dependent toxicity. The pathogenetic role of different immunosuppressants remains to be evaluated.
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PMID:Severe hearing loss after liver transplantation. 1591 4

Hepatitis C virus (HCV) is a major cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma worldwide. HCV has a positive-strand RNA genome of about 9.4 kb in size, which serves as a template for replication and for translation of a polyprotein of about 3,000 amino acids. The polyprotein is cleaved co- and posttranslationally by cellular and viral proteases into at least 10 different mature proteins. One of these proteins, nonstructural protein 3 (NS3), has serine protease and NTPase/RNA helicase activity. Arginine 467 in the helicase domain of NS3 (arginine 1493 in the polyprotein) can be methylated by protein arginine methyltransferase 1 (PRMT1). Here we report that the methylation of NS3 inhibits the enzymatic activity of the helicase. Furthermore, we found that PRMT1 activity itself is regulated by protein phosphatase 2A (PP2A). PP2A inhibits PRMT1 enzymatic activity and therefore increases the helicase activity of NS3. This is important, because we found an increased expression of PP2A in cell lines with inducible HCV protein expression, in transgenic mice expressing HCV proteins in hepatocytes, and in liver biopsy samples from patients with chronic hepatitis C. Interestingly, up-regulation of PP2A not only modulates the enzymatic activity of an important viral protein, NS3 helicase, but also interferes with the cellular defense against viruses by inhibiting interferon-induced signaling through signal transducer and activator of transcription 1 (STAT1). We conclude that up-regulation of PP2A might be crucial for the efficient replication of HCV and propose PP2A as a potential target for anti-HCV treatment strategies.
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PMID:Upregulation of protein phosphatase 2Ac by hepatitis C virus modulates NS3 helicase activity through inhibition of protein arginine methyltransferase 1. 1630 5

Branched-chain alpha-keto acid dehydrogenase (BCKDH) complex, the enzyme catalyst for the second step of the BCAA catabolic pathway, plays a central role in the regulation of BCAA catabolism. The activity of the complex is regulated by a covalent modification cycle in which phosphorylation by BCKDH kinase inactivates and dephosphorylation by BCKDH phosphatase activates the complex. Many studies suggest that control of the activity of the kinase is a primary determinant of the activity of the complex. The kinase exists at all times in the mitochondrial matrix space in two forms, with a large amount being free and a smaller amount bound rather tightly to the BCKDH complex. Only the bound form of the kinase appears to be catalytically active and, therefore, responsible for phosphorylation and inactivation of the complex. alpha-Ketoisocaproate, the transamination product of leucine and the most important known physiological inhibitor of BCKDH kinase, promotes release of the kinase from the complex. alpha-Chloroisocaproate, the analogue of leucine and the most potent known inhibitor of the kinase, is more effective than alpha-ketoisocaproate in promoting release of BCKDH kinase from the complex. Exercise and chronic liver disease (liver cirrhosis) likewise decrease the amount of the kinase bound to the complex in rat liver. The resulting activation of the BCKDH complex appears responsible for the increase in BCAA catabolism caused by exercise and liver cirrhosis. Our findings support the use of BCAA supplements for patients with liver cirrhosis.
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PMID:Branched-chain amino acid catabolism in exercise and liver disease. 1636 92

The severity of recurrent hepatitis C virus (HCV) is likely related to several factors. Controversial results have been reported regarding the effect of specific calcineurin-inhibitors. The aim of this research was to determine whether there are differences on posttransplantation outcome in HCV-infected patients based on initial immunosuppression. Prospective randomized trial comparing tacrolimus vs. cyclosporine-based immunosuppression in a cohort of patients undergoing primary orthotopic liver transplantation between 2001 and 2003 was used. Yearly biopsies were performed. Patients with at least 1 protocol biopsy and those with very severe recurrence despite a follow-up of less than 1 yr (cholestatic hepatitis, progression to bridging fibrosis/cirrhosis) were included. Baseline characteristics (demographics, liver function at transplantation, genotype distribution, donor, surgery, immunosuppression except for the type of calcineurin inhibitor) did not differ between the 2 groups. Severe disease (defined as bridging fibrosis, cirrhosis, cholestatic hepatitis, and/or death due to recurrent disease in the first year) was present in 27 in 90 (30%), and was equally distributed in the cyclosporine and tacrolimus groups (15/46 vs. 12/44, respectively). A total of 33 in 90 (37%) patients had no fibrosis in the first year biopsy with no difference between the cyclosporine and tacrolimus groups (36.5 vs. 37%). The percentage of patients developing recurrent acute hepatitis was also similar (32% vs 35%); time to acute hepatitis though was shorter in the tacrolimus group (59 days [35-185] vs. 92 days [39-343] in the cyclosporin group; P = 0.02). Cholestatic hepatitis was observed in 4 of 44 and 5 of 46 patients under cyclosporine and tacrolimus, respectively (P = not significant). In conclusions, the short-term posttransplantation course of hepatitis C is not related to the calcineurin inhibitor used.
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PMID:Effect of calcineurin inhibitors on survival and histologic disease severity in HCV-infected liver transplant recipients. 1662 96

Successful immunosuppressive therapy is critical for liver transplantation. However, a considerable number of patients show clinical resistance to the therapy and experience rejection episodes, or alternatively exhibits serious adverse effects of drugs. We examined the in vitro response of peripheral blood mononuclear cells (PBMCs) to immunosuppressive drugs in cirrhosis patients awaiting liver transplantation. We evaluated the suppressive efficacy of prednisolone, methylprednisolone, cyclosporine, and tacrolimus on the in vitro blastogenesis of PBMCs obtained from 22 cirrhosis patients and 31 healthy subjects. In vitro drug concentrations giving 50% inhibition of PBMC blastogenesis (IC50s) were calculated. Two out of these 22 patients received liver transplantation from living donors, and their clinical courses were surveyed until 5 weeks after operation. The median IC50 values for prednisolone, cyclosporine, and tacrolimus against blastogenesis of PBMCs from cirrhosis patients were significantly lower than those of PBMCs from healthy subjects (p < 0.01). However, large individual differences were observed in the IC50 values of the immunosuppressive drugs examined, especially in the cirrhosis patients. One recipient exhibiting high PBMC sensitivity to tacrolimus (IC50 = 0.001 ng/ml) showed good clinical course without rejection until 5 weeks after liver transplantation. The other recipient exhibiting relatively low PBMC sensitivity to taclolimus (IC50 = 0.30) showed allograft rejection at 1 week after operation. We concluded from these observations that PBMCs of cirrhosis patients are vulnerable to the immunosuppressive effects of prednisolone and calcineurin inhibitors. However, large individual variations in the IC50 values suggest that patients exhibiting relatively lower sensitivity to these drugs may have risks of rejection, whereas highly sensitive patients are possibly able to reduce the dose of immunosuppressive drugs to avoid serious drug-adverse effects, after liver transplantation.
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PMID:Increased sensitivities of peripheral blood mononuclear cells to immunosuppressive drugs in cirrhosis patients awaiting liver transplantation. 1729 93

Recurrent hepatitis C ranges from minimal damage to cirrhosis developing in a few months or years in a substantial proportion of transplant recipients. Different virus, host and donor factors are involved in the pathogenesis of recurrence, but many are poorly understood. Therapeutic strategies can be utilized in the pre-, peri- or posttransplantation setting. Antiviral therapy using interferon and ribavirin and modifying immunosuppression are the main strategies to prevent progression disease. The efficacy of interferon and ribavirin is limited and side effects, reduction/withdrawal are frequent. Current sustained virological response rates are approximately 28%. An optimal immunosuppression regimen has not been established. The choice of calcineurin inhibitors has not clearly been shown to affect histological hepatitis C virus (HCV) but higher cumulative exposure to corticosteroids to treat acute rejection is associated with more severe recurrence. The manner in which the doses of immunosuppression are modified has more influence on HCV recurrence than the use of a specific drug per se. Debate about the influence of immunosuppressive regimens on HCV recurrence is ongoing. Potential antifibrotic therapy and new agents targeting HCV infection and replication are emerging and are anticipated to be added to our armentarium in battling recurrent HCV post-LT.
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PMID:Therapeutic management of recurrent hepatitis C after liver transplantation. 1735 50

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