Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0015695 (fatty liver)
 13,941 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report three cases of hepatic steatosis associated with lactic acidosis occurring in HIV positive patients and due to a toxicity of antiviral nucleoside analogues. The clinico-pathological presentation was similar associating digestive signs (vomiting and abdominal pain), polypnea, lactic acidosis, a lethal clinical course, and an hepatomegaly with a diffuse macrovacuolar steatosis. The ultrastructural study performed in two cases showed mitochondrial alterations in hepatocytes. The toxicity of antiviral nucleoside analogues is due to a mitochondrial DNA polymerase inhibition. The incidence of this disease is actually low but probably underestimated. The diagnosis should be rapidly performed and the treatment immediatly interrupted.
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PMID:[A rare etiology of hepatic steatosis associated with lactic acidosis: the toxicity of antiviral nucleoside analogues]. 1137 88

The introduction of newer and more potent agents has diverted attention away from the importance of nucleoside analogue reverse transcriptase inhibitors (NRTIs) in modern antiretroviral drug regimens. As a class, these proviral chain terminators lack the virological potency of either non-nucleoside reverse transcriptase inhibitor (NNRTI) or protease inhibitor (PI) drugs, due largely to their competitive mode of inhibition and requirement for metabolic activation. However, neither NNRTIs nor PIs alone can maintain the complete suppression of HIV replication required for extended therapy, and both suffer from serious class cross-resistance on therapeutic failure. Thus, the NRTIs will remain essential components of highly active antiretroviral therapy (HAART) for the foreseeable future, both for their contribution to a regimen's virological potency and the subsequent preservation of the more potent drug classes used with them. However, it has become apparent in recent years that the current NRTIs exhibit duration-dependent adverse events as a class, which may limit the length of time for which they can be safely used. An independent contribution to peripheral fat wasting in lipodystrophy syndrome has been established for the use of NRTI drugs. Of greater clinical concern is their established association with potentially fatal lactic acidaemia and hepatic steatosis. Both these class events, as well as several individual drug events, such as peripheral; neuropathy, can be linked to progressive mitochondrial destruction with a greater or lesser degree of confidence. Mitochondrial toxicity, due in large part to the high affinity of several NRTI agents for uptake by mitochondrial DNA polymerase gamma, has been demonstrated both in vitro and in vivo. New chain-terminating agents are urgently needed that address issues of improved virological potency, greater efficacy in NRTI-experienced individuals, and greater long-term safety. The nucleotide class of reverse transcriptase inhibitor (NtRTI), currently under clinical development, addresses improved potency by abbreviating the intracellular activation pathway to allow a more rapid and complete conversion to the active agent. These nucleoside monophosphate analogues are taken as masked prodrugs bearing labile lipophilic groups to facilitate penetration of target cell membranes. Subsequent unmasking by endogenous chemolytic enzymes releases a partially activated nucleoside analogue metabolite. The NtRTI furthest along the developmental process is tenofovir disoproxil fumarate (TDF), an orally available acyclic adenine phosphonate analogue, currently in Phase III clinical trials. This agent has shown high potency and an unusually durable response in trials of single-agent therapy intensification in highly treatment-experienced individuals, and its active metabolite, tenofovir diphosphate, exhibits a long intracellular half-life in both resting and activated peripheral blood mononuclear cells that permits once daily dosing. Tenofovir diphosphate also exhibits a very low affinity for DNA polymerase gamma in vitro, suggesting a low degree of in vivo mitochondrial toxicity may be observed on long-term follow-up, although clinical data to support this inference are not yet available. The introduction of TDF and other NtRTIs as 'second-generation' nucleoside analogues carefully evaluated for potential long-term toxicity, can be expected to significantly improve the therapeutic options for both those currently on HAART and those yet to begin.
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PMID:An introduction to nucleoside and nucleotide analogues. 1167 69

Hepatic steatosis is common in patients with chronic hepatitis C virus (HCV) infection. Epidemiologic studies have shown HCV-associated steatosis to correlate with both patient factors, such as obesity and viral factors, such as HCV genotype 3a. Furthermore, the degree of steatosis has been linked to the extent of hepatic fibrosis in several studies, implying that steatosis may be contributing to disease progression in chronic HCV infection. Whether the pathogenesis of HCV-associated steatosis is linked to oxidative damage non-specifically, to HCV viral properties, or to other factors remains unknown. This steatosis may play an important role in the response to HCV therapy, in disease progression after liver transplantation for HCV, or in HIV-HCV coinfection.
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PMID:Hepatitis C and steatosis. 1194 33

Anti-retroviral therapy has still many difficulties for the continuous viral suppression, although it has markedly improved the prognosis of the patients with HIV/AIDS. It is essential that anti-retroviral therapy requires strict adherence of the patients. More than 95% of adherence to have medicine is required for the success of the therapy. Severe and frequent adverse reactions, many pill burden, food restriction and patients' poor recognition to the therapy influence adherence. Of those, adverse reaction of the drugs is the strongest factor for disturbing adherence. Digestive tract symptoms such as nausea, vomiting, abdominal pain and/or diarrhea are common and affect to reduce adherence. Recently, lactic acidosis/hepatic steatosis and lipodystrophy syndrome have been recognized as novel and important adverse reactions with anti-retroviral medicines. Physicians should be aware of the importance of adherence, and assist the patients to improve it with multiple approaches.
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PMID:[Challenges of the anti-retroviral therapy]. 1196 83

Nucleoside analog reverse transcriptase inhibitors (NRTI) have been used to treat HIV-infected patients for >10 years. Some severe adverse events have been attributed to mitochondrial dysfunction. Since 1991, cases of severe lactic acidosis have been reported in association with nucleoside therapy. Our objective was to report two cases of metabolic acidosis and hepatic steatosis in patients receiving stavudine (d4T) and to review the literature. A male and a female, 47 and 45 years of age, respectively, presented with abdominal pain, nausea, vomiting, and weakness after 9 and 6 months, respectively, of treatment with stavudine. At presentation, both patients had severe metabolic acidosis and liver failure. Ultrasonography showed hepatic steatosis (confirmed by biopsy in one case). All antiretroviral drugs were withdrawn and patients were treated with bicarbonate. Both patients developed fulminant liver dysfunction and multiple organ failure. We reviewed the literature and found 75 cases of lactic acidosis and hepatic steatosis associated with use of NRTI; 57 of these patients received d4T (76%). Of all cases reported in association with nucleoside therapy, 63% were females and mortality was 47%. General weakness, hepatic enzyme elevation, and liver steatosis are data that should alert physicians to this serious adverse event and to respond with prompt interruption of antiretroviral drugs and measurement of lactic acid in plasma. It is important to report serious adverse events in commercially released drugs to know prevalence in an exposed population. Physicians should be aware of risk and early signs of this serious adverse event.
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PMID:Metabolic acidosis and hepatic steatosis in two HIV-infected patients on stavudine (d4T) treatment. 1260 78

HAART has resulted in dramatic declines in morbidity and mortality among patients infected with HIV. Increased experience with HAART has led to the detection of drug related toxicities that may compromise adherence and necessitate discontinuation of treatment and alteration of otherwise effective regimens. This article considers the major long-term complications associated with nucleoside reverse transcriptase inhibitor (NRTI) use--hyperlactatemia and lactic acidosis/hepatic steatosis, other hepatotoxicities, pancreatitis, lipodystrophy, lipoatrophy, neuropathy, and hematologic toxicities. Mechanisms by which NRTIs may produce these effects are discussed, as are differential effects of agents in this class and management options.
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PMID:Long-term complications of nucleoside reverse transcriptase inhibitor therapy. 1274 68

Hyperlactataemia is seen in 8-18.3% of HIV-infected patients taking nucleoside-analogue reverse transcriptase inhibitors (NRTIs). Recent epidemiological studies suggest that most episodes are transient and subclinical. However, symptomatic and occasionally life-threatening cases accompanied by metabolic acidosis and hepatic steatosis (ie, lactic acidosis syndrome) have also been described. Though yet to be fully elucidated, the proposed mechanism is NRTI-induced inhibition of mitochondrial DNA polymerase culminating in derangements in oxidative phosphorylation and lactate homeostasis. Signs and symptoms range from mild hyperlactataemia accompanied by nausea, abdominal discomfort, and weight loss to severe, intractable lactic acidosis complicated by coma and multi-organ failure. Significant progress has recently been made with regard to the natural history of NRTI-related hyperlactataemia. However, other important aspects of the disorder, such as its pathogenesis, predisposing conditions, and management, remain poorly understood. This article reviews the current published work on these issues, identifies areas of controversy, and addresses directions for future research.
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PMID:Hyperlactataemia syndromes associated with HIV therapy. 1452 59

Muscular fatigue may result from HIV infection, and may be associated with antiretroviral drug treatment. Clinical features linked to muscle biopsy findings may assist in determining etiology, and guide treatment decisions. This case series examined HIV patients in an ambulatory HIV clinic who received antiretroviral therapy, and complained of unexplained muscular fatigue. Clinical features with measurement of acid-base status, levels of lactate, aminotransferases, triglycerides and creatine kinase were correlated to light and electron microscopic results of muscle biopsy. Three patients with acquired mitochondrial changes on biopsy shared common features of lactatemia, elevated aminotransferases and triglycerides, and ultrasonographic hepatic steatosis. A fourth patient with normal mitochondria had myositis with fibrosis, but no systemic symptoms. Biochemical parameters were unremarkable, except for a high creatine kinase. Acquired mitochondrial disease may manifest as systemic illness and muscular fatigue. Unique metabolic changes and other organ dysfunction may precede overt physical signs of HIV myopathy.
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PMID:Clinical correlates to muscle biopsy findings in HIV patients experiencing fatigue: a case series. 1294 81

HIV caregivers face many challenges following initiation of ART. The development of jaundice is uncommon but worrisome. In this case, two distinct and contrasting episodes of jaundice were observed. In the first instance, isolated elevation of the indirect bilirubin without elevation of the alkaline phosphatase was noted. The normal PT and serum aminotransferase levels indicate the absence of intrinsic liver dysfunction. Elevations in the indirect bilirubin may result from either impaired uptake/conjugation or excess production. The latter, usually from acquired hemolysis, may be a complication of an occult NHL. A work-up for this AIDS-related malignancy was not initiated since the caregivers recognized jaundice as a complication of IDV, which inhibits UDP-glucuronyl transferase and produces a Gilbert's-like syndrome. Physicians can expect to encounter this syndrome even more frequently with ATV. Experienced patients given RTV-boosted ATV have experienced elevations of unconjugated hyper-bilirubinemia in up to 45 percent of cases in clinical trials. However, such elevations do not reflect liver dysfunction and symptomatic jaundice requiring dosage reduction that occurred infrequently (7 to 8 percent of study patients). Counseling patients about this syndrome may promote adherence and prevent self-directed interruptions of ATV that compromise efficacy. The second case of jaundice provides a more formidable diagnostic challenge. The triad of LFT abnormalities (mild elevation of aminotransferases, normal PT, and marked cholestatic jaundice) implies an acute process that is mildly toxic to hepatocytes without affecting their synthetic function. The subacute nature of the patient's cholestatic jaundice suggests either intrahepatic infiltrative disease of the liver or extrahepatic obstruction of the biliary tree, most likely due to the patient's relatively modest level of pain and lack of fever. Despite LFT abnormalities occurring 17 months after a switch in his ART, cumulative drug-related toxicities must still be considered. Ritonavir can produce significant elevations in the AST/ALT, especially with pre-existing chronic liver disease as with hepatitis C virus coinfection. The NRTIs can produce hepatic steatosis, a result of mitochondrial toxicity and impaired fatty acid oxidation. However, jaundice and cholestasis are not typical of the latter syndrome. With a negative contrast CT that excludes parenchymal liver disease, investigation of the biliary tree to assess the presence of AIDS-related cholangitis was the next step. Performing a sphincterotomy or stent placement, and obtaining brushings or biopsy specimens to determine the extent of extrahepatic obstruction may help define a pathogen and be life-saving. The negative results of the ERCP justify the final diagnostic step, a liver biopsy to evaluate microscopic infiltrative disease that might not have been detected on contrast abdominal CT. Examples might include granulomatous disease (MAC), fungal etiologies (histoplasmosis), carcinomatosis (lymphoma, hepatoma, cholangiocarcinoma), and microvascular disease (bacillary angiomatosis). The failure to observe granulomatous inflammation in the liver does not exclude MAC infection, as MAC may involve other peri-aortic or mesenteric lymph nodes. This form of IRIS is unlikely given the abdominal CT findings, lack of systemic complaints, and extended persistence of liver aminotransferases. The nonspecific results of the liver biopsy are a common outcome in advanced AIDS patients with elevated alkaline phosphatase levels. Despite not having identified a pathogen, the biopsy establishes chronic liver disease and prompts re-evaluation and change of treatment to NFV. The subsequent normalization of the patient's aminotransferase levels suggests a prior adverse effect of LPV/r in the setting of unexplained, chronic liver disease. Most importantly, this case highlights the importance of HIV caregivers to review ART for safety when noting chronic liver dysfunction. Patients need to be counseled to minimize acetaminophen use, to consume alcohol in moderation, and to avoid behavior with risk for hepatitis C. Finally, all HIV patients should receive appropriate vaccination against hepatitis A and B if serology shows lack of protective immunity.
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PMID:Clinical vignette in antiretroviral therapy: jaundice. 1498 14

The development of novel compounds that can effectively inhibit both wild type and the most consensus resistant strains of human immunodeficiency virus type 1 (HIV-1) is the primary focus in HIV disease management. Combination therapy, comprising at least three classes of drugs, has become the standard of care for acquired immunodeficiency syndrome (AIDS) or HIV-infected individuals. The drug cocktail can comprise all three classes of HIV inhibitors, including nucleoside reverse transcriptase inhibitors (NRTI), non-nucleoside reverse transcriptase inhibitors (NNRTI) and protease inhibitors (PI). Due to their competitive mode of inhibition and requirement for metabolic activation, almost all NRTI drugs lack the virological potency of NNRTI or PI drugs. However, data from clinical trials indicate that sustained viral suppression could not be achieved with NRTI, NNRTI or PIs alone. Therefore, the NRTIs will remain essential components of highly active antiretroviral therapy (HAART) for the foreseeable future, because they enhance the virological potency of the regimen, they do not bind excessively to protein and most regimens are small pills/tablets given once a day. It has become apparent in recent years that the prolonged use of certain NRTIs exhibits adverse events as a class, limiting the length of time for which they can be safely used. Of major clinical concern is their association with the potentially fatal lactic acidaemia and hepatic steatosis. These class events, as well as individual drug effects, such as peripheral neuropathy, are linked to delayed mitochondrial destruction. In addition to toxicity, the development of resistance-conferring mutations against exposure to nucleoside analogs currently in use influences long-term therapeutic benefits. Of critical importance for the evaluation of new NRTIs are recent studies showing that the efficiency of discrimination or excision by pyrophosphorolysis in the presence of nucleotides of a given NRTI is a key determinant in the emergence of one or the other resistance pathway.
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PMID:Nucleoside inhibitors of human immunodeficiency virus type 1 reverse transcriptase. 1513 48


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