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)

Protein misfolding and aggregation play an integral role in many diseases. The misfolding of the serpin (SERine Proteinase INhibitor) alpha1-antitrypsin results in the accumulation of insoluble polymers within hepatocytes and alpha1-antitrypsin deficiency in plasma, predisposing patients to liver cirrhosis and emphysema. We have examined the effect of three naturally occurring osmolytes, sarcosine, glycine betaine and trimethylamine N-oxide, on conformational changes in alpha1-antitrypsin. All three solutes protected native alpha1-antitrypsin against thermally induced polymerisation and inactivation in a concentration-dependent manner. Further spectroscopic analysis showed that sarcosine stabilises the native conformation of alpha1-antitrypsin, thus hindering its conversion to an intermediate state and subsequent polymerisation. On refolding in the presence of sarcosine, alpha1-antitrypsin formed a heterogeneous population, with increasing proportions of molecules adopting an inactive conformation in higher concentrations of the osmolyte. These data show that sarcosine can be used to prevent abnormal structural changes in native alpha1-antitrypsin, but is ineffective in facilitating the correct folding of the protein. The implications of these results in the context of conformational changes and states adopted by alpha1-antitrypsin are discussed.
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PMID:Osmolytes as modulators of conformational changes in serpins. 1176 49

Nonalcoholic fatty liver disease is emerging as the most common liver disease in North America. The histological spectrum of nonalcoholic fatty liver disease ranges from fatty liver alone to steatohepatitis and to the most serious form--nonalcoholic steatohepatitis (NASH). An increasing body of evidence suggests that NASH is associated with the development of progressive fibrosis and eventually cirrhosis in approximately 20% of cases. These data emphasize the need to develop effective therapy for the treatment of NASH. Cases occur most commonly in obese middle age women with diabetes. However, NASH may also occur in children and normal weight men with normal glucose and lipid metabolism. The pathophysiology involves 2 steps. The first is insulin resistance, which causes steatosis. The second is oxidative stress, which produces lipid peroxidation and activates inflammatory cytokines resulting in NASH. Liver biopsy provides prognostic information and identifies NASH patients who may benefit from therapy. Treatment consists of managing the comorbidities: obesity, diabetes, and hyperlipidemia. Nascent clinical trials suggest that a number of therapies may be beneficial. These include anti-oxidants such as vitamin E and betaine, bile acid therapy with ursodeoxycholic acid, and improved insulin sensitivity with metformin. Another potential therapeutic strategy is the reduction of inflammatory cytokines.
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PMID:Diabetes mellitus, obesity, and hepatic steatosis. 1194 30

Nonalcoholic fatty liver disease (NAFLD) encompasses a broad clinicopathologic spectrum ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), which may advance to cirrhosis and end-stage liver disease. Steatosis alone does not appear to be progressive. The prevalence of NAFLD averages 20% and that of NASH, 2% to 3%, making these conditions the most common liver diseases in the United States. NAFLD is associated with insulin resistance, which may be evident clinically with obesity, type 2 diabetes mellitus, and hypertriglyceridemia. The pathogenesis of NAFLD consists of hepatic fat accumulation and oxidative stress with formation of free radicals. The clinical diagnosis is based on the presence of the insulin resistance syndrome and exclusion of alcohol abuse as well as viral, autoimmune, genetic, and drug-induced liver diseases. Liver biopsy is essential for diagnosis but may not be necessary for clinical management. Treatment is aimed at correcting the risk factors for NAFLD and using potentially hepatoprotective agents. Ursodeoxycholic acid and betaine appear particularly promising in early trials.
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PMID:Nonalcoholic fatty liver disease. 1212 75

Nonalcoholic fatty liver disease (NAFLD) includes a wide spectrum of liver injury ranging from simple steatosis to steatohepatitis, fibrosis, and cirrhosis. Whereas simple steatosis has a benign clinical course, steatohepatitis is a recognized cause of progressive liver fibrosis and can develop into cirrhosis. NAFLD and nonalcoholic steatohepatitis (NASH) are the two most common chronic liver diseases in United States general population with a prevalence of 20% and 3%, respectively. Hepatic steatosis is frequently associated with obesity, type 2 diabetes, and hyperlipidemia with insulin resistance as a key pathogenic factor. A two-hit theory best describes the progression from simple steatosis to NASH, fibrosis, or cirrhosis. These two hits consist of the accumulation of excessive hepatic fat primarily owing to insulin resistance, and oxidative stress owing to reactive oxygen species (ROS). Mitochondria are the major cellular source of ROS in cases of NASH. Currently, treatment is focused on modifying risk factors such as obesity, diabetes mellitus, and hyperlipidemia. Antioxidants such as vitamin E, N-acetylcysteine, betaine, and others may be beneficial in the treatment of NASH.
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PMID:Nonalcoholic fatty liver disease: pathogenesis and the role of antioxidants. 1229 56

Nonalcoholic fatty liver disease, an entity that includes nonalcoholic steatohepatitis, is typically a benign, indolent condition. However, in a subset of patients, the clinical course may progress to advanced cirrhosis, end-stage liver disease, or hepatocellular carcinoma. Unfortunately, the pathogenesis, natural history, and potential therapies for these disorders remain poorly understood. Identifying patients who should be targeted for potential treatment remains difficult. Liver biopsy should be considered to assess the degree of hepatic inflammation and fibrosis, because physical examination findings, biochemical parameters, and the results of radiographic studies have been shown to correlate poorly with the severity of steatohepatitis and fibrosis. Although there is some evidence suggesting that obesity, diabetes mellitus, older age, and perhaps an aspartate transaminase:alanine aminotransaminase ratio higher than 1 may be predictors of more advanced fibrosis, histology remains the gold standard. Most patients with simple hepatic steatosis appear to follow a benign course and probably do not require aggressive therapy. Conversely, patients with steatohepatitis with extensive inflammation and fibrosis are the patients who are most likely to benefit from effective therapies. The most commonly recommended treatment is weight loss. Existing data suggest that rapid weight loss may promote hepatic inflammation and fibrosis; therefore, gradual weight loss should be recommended. Large, randomized, controlled trials evaluating the long-term histologic impact and clinical outcomes of weight loss strategies are lacking. Potentially promising pharmacologic therapies include insulin-sensitizing oral hypoglycemic agents such as metformin and the thiazolidenediols, antihyperlipidemic agents such as gemfibrozil or 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, vitamin E and other antioxidants, ursodeoxycholic acid, and betaine. As with weight loss, data regarding the efficacy of these pharmacologic options are limited. In addition, there are no widely accepted guidelines to help direct the clinician in the optimal use of these agents in patients with nonalcoholic fatty liver diseases.
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PMID:Therapeutic Options in Nonalcoholic Fatty Liver Disease. 1240 79

Nonalcoholic fatty liver disease (NAFLD) is very common in the United States, and in some patients it may lead to cirrhosis, liver failure, and liver cancer. NAFLD encompasses a spectrum of liver injury, ranging from steatosis to steatohepatitis, advanced fibrosis, and cirrhosis. Nonalcoholic steatohepatitis (NASH), an advanced form of NAFLD, histologically comprises steatosis, balloon degeneration, inflammation, and fibrosis in varying degrees. It is generally believed that simple steatosis is benign with minimal risk of progression, whereas NASH is progressive and can lead to cirrhosis. The commonly associated risk factors for NAFLD include obesity, hyperlipidemia, and diabetes mellitus. The pathogenesis of NAFLD and NASH is not fully known; however, current evidence suggests that insulin resistance and lipid peroxidation play a role in the pathogenesis of this condition. Currently, there are no proven effective therapies available for the treatment of NASH. Although there are numerous studies that have explored various treatments for NASH, these generally consist of small numbers of patients with suboptimal endpoints. Treatment strategies for NAFLD and NASH can be broadly divided into 1) treatment or control of underlying risk factors such as hyperlipidemia, diabetes mellitus, and obesity; and 2) specific pharmacologic therapy such as insulin sensitizers, antioxidants, or cytoprotective agents. Newer thiazolidinediones, such as rosiglitazone and pioglitazone, have shown promise in the treatment of NASH in pilot studies. However, these agents should not be used in clinical practice until their efficacy and safety are firmly established in larger studies. Despite encouraging initial studies, the recently completed multicenter, randomized, controlled trial failed to show any efficacy for ursodeoxycholic acid in the treatment of NASH. Other agents, such as vitamin E, betaine, probucol, and atorvastatin, have been explored as therapeutic agents for NASH. However, none of these studies have shown convincingly their utility in the treatment of NASH. Attempts to identify optimal therapy for patients with NASH are being vigorously pursued by the research community and important advances are expected within next several years. Until then, subjects should be advised to avoid alcohol, lose weight, and exercise regularly, and meticulous attention should be paid to the control of their risk factors such as diabetes and hyperlipidemia.
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PMID:Treatment of Nonalcoholic Fatty Liver Disease. 1458 34

Obesity has emerged as a significant new health problem in the pediatric population. Non-alcoholic steatohepatitis (NASH) is an entity in the spectrum of non-alcoholic fatty liver disease (NAFLD) ranges from fat in the liver -- simple steatosis, NASH/ steatohepatitis -- fat with inflammation and/or fibrosis to advanced fibrosis and cirrhosis when fat may no longer be present. NASH is associated with obesity, diabetes, insulin resistance (IR), and hypertriglyceridemia. While majority of individuals with risk factors like obesity and IR have steatosis only a minority develop steatohepatitis, possible mechanisms have been discussed. Clinical experience with pediatric NASH is limited. Children generally present in the prepubertal age group, have a male predominance with a higher incidence in children of Hispanic origin. Body mass index (BMI) of 25-29.9 is considered to be overweight and that > or =30 obese. Acanthosis nigricans as a marker of IR should be looked for. As NASH is a diagnosis of exclusion, other causes of chronic liver disease must be excluded. Increased echogenicity in the liver is noted on ultrasound. Liver biopsy is considered the gold standard in establishing the diagnosis. Histopathological lesions thought to be necessary for diagnosis of NASH include steatosis (macrovesicular > microvesicular), mixed mild lobular inflammation and hepatocyte ballooning. A system of grading depending on degree of steatosis and/or inflammation and staging depending on the extent of fibrosis has also been proposed. Although there is no consensus for the treatment for NASH, effort needs to be made to prevent development of fibrosis, which results in cirrhosis and portal hypertension. Slow, consistent weight loss has been shown to be effective in childhood NAFLD, based on improvement of serum aminotransferases or liver sonogram. A low glycemic index diet has been shown to be more effective than a low fat diet in lowering BMI. Family based behavioral intervention may also enhance success with diet. Several pharmacological agents have been used including ursodeoxycholic acid, vitamin E, betaine, n-acetyl cysteine, and insulin sensitizing agents like metformin, rosiglitazone, and pioglitazone. Transplantation for overt NASH is rare, accounting for < 1% of liver transplantations in the USA. The disease can recur after liver transplantation. A strong association exists between the presence of steatosis in a donor liver and poor graft function. As a result, cadaveric donor livers with macrovesicular steatosis >40% are not used routinely. Prognosis in NASH is dependent not only on severity and number of risk factors but also on the degree of histological damage. Clinical trials are needed to identify an effective treatment that halts the progression of NAFLD to NASH in both pretransplantation and post-transplantation patients.
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PMID:Non-alcoholic steatohepatitis in children. 1559 36

The term 'non-alcoholic fatty liver disease' (NAFLD) includes cases with steatosis alone and those with non-alcoholic steatohepatitis (NASH). Usually there are no signs or symptoms, sometimes fatigue or pain, and apart from hepatomegaly the condition is revealed by abnormal liver biochemistry or by abdominal ultrasound. Most cases are associated with overweight or diabetes. Liver enzymes are usually elevated, especially GGT, ASAT and ALAT. Other conditions, including alcohol abuse and autoimmune hepatitis, have to be excluded. The diagnosis of steatosis can be made with ultrasound or CT scan. A liver biopsy is often needed to exclude other disease and to assess inflammation and fibrosis. Cirrhosis can develop. NAFLD is usually caused by two 'hits': the 'first hit' is peripheral insulin resistance, causing steatosis. The 'second hit' is caused by reactive oxygen species, inducing vicious cycles leading to inflammation. Weight loss, metformin or thiazolidinediones can improve NAFLD by increasing insulin sensitivity. Radical scavengers such as vitamin E, betaine and perhaps also urodeoxycholic acid may improve the hepatitis component. Further studies on treatment are needed.
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PMID:Non-alcoholic fatty liver disease: a brief review. 1569 51

Nonalcoholic fatty liver disease (NAFLD) is becoming an increasing cause of chronic liver damage. The decision of start a medical treatment is based on the documented risk of progression to cirrhosis and liver cancer, when steatohepatitis (NASH) occurs. The therapy of this syndrome requires, as obviously, some considerations on the natural history of the condition, on the efficacy and safety of various therapeutic options, as well as on the costs. Treatment of patients with NAFLD has typically been focused on the management of associated conditions such as obesity, diabetes mellitus and hyperlipemia. Weight loss improves insulin sensitivity, and NASH may resolve with weight reduction. Insulin resistance seems to be the common denominator in many cases of NAFLD. Two classes of drugs have been shown to correct insulin resistance: biguanides (e.g., metformin) and thiazolidinediones (e.g., rosiglitazone and pioglitazone). The last two decades have witnessed a considerable progress in the understanding of the mechanisms respon-sible for the fibrogenic progression of chronic liver diseases. Several drugs believed to be hepatoprotective or antifibrotic agent as UDCA, betaine, vitamin E, lecithin, beta-carotene and selenium have been used in patients with NASH. Silybin is the main component of silymarin that is absorbed when linked whith a phytosome. This substance reduces in rats the lipid-peroxidation and the activaction of hepatic stellate cells. In humans, some non controlled data show that silybin is able to reduce insulin resistance, liver steatosis and plasma markers of liver fibrosis.
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PMID:The treatment of NAFLD. 1623 94

The intimate relation between amino acids and protein and nitrogen requirements is well recognized. Nutrition research has focused on the capacity of food to meet the need for nitrogen and indispensable amino acids (IAA) and led to the conclusion that the quality, not just the quantity, of protein is critical. This is especially relevant in regard to the sulfur amino acids (SAA) methionine and cysteine because of the increased understanding of their relation to chronic diseases (e.g., cardiovascular disease, dementia, cirrhosis), immunomodulation, DNA transcription, and RNA translation. Considerable effort has been expended to determine whether and to what extent cysteine can spare the requirement for the IAA methionine. In vivo studies in humans generally concur that the dietary requirement of the SAA ranges between 13 and 16 mg.kg(-1).d(-1), but how much can be met by cysteine relative to methionine remains controversial. This review examines the current status of in vivo estimates of methionine and cysteine requirements in human adults and considers needs beyond what is necessary for protein synthesis. Factors influencing the utilization of methionine and cysteine, especially those conditions that lead to toxicity on the one hand or beneficial effects on the other, are discussed. Data on alternative dietary sources of methyl groups (e.g., betaine, choline, phosphatidylcholine, S-adenosylmethionine, S-methylmethionine) or sulfur (e.g., N-acetylcysteine or L-2-oxothiazolidine-4-carboxylic acid) support a role for the SAA "beyond protein." Other pathways may influence the specific requirement for methionine and/or cysteine, especially when the person is challenged by disease, inadequate availability of food, or environmental stress.
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PMID:Sparing of methionine requirements: evaluation of human data takes sulfur amino acids beyond protein. 1670 39


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