Betaine, a promising new agent for patients with nonalcoholic steatohepatitis: results of a pilot study

A double-blind randomized placebo-controlled trial of orlistat for the treatment of nonalcoholic fatty liver disease

BACKGROUND & AIMS

Few controlled studies have addressed the issue of effective medical treatment for nonalcoholic fatty liver disease (NAFLD). We herein assessed the effect of orlistat in patients with NAFLD.

METHODS

We performed a randomized, double-blind, placebo-controlled study on 52 patients with NAFLD diagnosed by ultrasound (US) and confirmed by liver biopsy (40 patients). The patients were randomized to receive either orlistat (120 mg 3 times daily for 6 months) or placebo. All patients participated in an identical behavioral weight loss program. All patients underwent monthly evaluation by abdominal US; liver enzyme levels, lipid profiles, insulin levels, and anthropometric parameters were monitored, and all patients underwent nutritional follow-up evaluation. Twenty-two patients underwent a second liver biopsy examination at the end of the study.

RESULTS

Fifty-two patients were recruited and 44 (mean age, 47.7 y; mean body mass index, 33) completed the study. Serum glucose and insulin levels (P<.03) were significantly higher in the orlistat group, which also presented a higher degree of fibrosis. Body mass index was reduced significantly in each group, with a nonsignificant difference between the groups. Serum alanine transaminase (ALT) levels decreased significantly in both groups, with an almost 2-fold reduction in the orlistat group (48% vs 26.4%). There was a statistically significant reversal of fatty liver by US only in the orlistat group (P<.05).

CONCLUSIONS

Orlistat improves serum ALT levels and steatosis on US in NAFLD patients, beyond its effect on weight reduction.

Hepatic very-low-density lipoprotein and apolipoprotein B production are increased following in vivo induction of betaine-homocysteine S-methyltransferase

We have previously reported a positive correlation between the expression of BHMT (betaine-homocysteine S-methyltransferase) and ApoB (apolipoprotein B) in rat hepatoma McA (McArdle RH-7777) cells [Sowden, Collins, Smith, Garrow, Sparks and Sparks (1999) Biochem. J. 341, 639-645]. To examine whether a similar relationship occurs in vivo, hepatic BHMT expression was induced by feeding rats a Met (L-methionine)-restricted betaine-containing diet, and parameters of ApoB metabolism were evaluated. There were no generalized metabolic abnormalities associated with Met restriction for 7 days, as evidenced by control levels of serum glucose, ketones, alanine aminotransferase and L-homocysteine levels. Betaine plus the Met restriction resulted in lower serum insulin and non-esterified fatty acid levels. Betaine plus Met restriction induced hepatic BHMT 4-fold and ApoB mRNA 3-fold compared with Met restriction alone. No changes in percentage of edited ApoB mRNA were observed on the test diets. An increase in liver ApoB mRNA correlated with an 82% and 46% increase in ApoB and triacylglycerol production respectively using in vivo Triton WR 1339. Increased secretion of VLDL (very-low-density lipoprotein) with Met restriction plus betaine was associated with a 45% reduction in liver triacylglycerol compared with control. Nuclear run-off assays established that transcription of both bhmt and apob genes was also increased in Met-restricted plus betaine diets. No change in ApoB mRNA stability was detected in BHMT-transfected McA cells. Hepatic ApoB and BHMT mRNA levels were also increased by 1.8- and 3-fold respectively by betaine supplementation of Met-replete diets. Since dietary betaine increased ApoB mRNA, VLDL ApoB and triacylglycerol production and decreased hepatic triacylglycerol, results suggest that induction of apob transcription may provide a potential mechanism for mobilizing hepatic triacylglycerol by increasing ApoB available for VLDL assembly and secretion.

S-Adenosylmethionine and betaine correct hepatitis C virus induced inhibition of interferon signaling in vitro

Hepatitis C virus (HCV) infection is an important cause of chronic liver disease. Standard therapy, pegylated interferon alpha (pegIFNalpha) combined with ribavirin, results in a sustained response rate in approximately half of patients. The cause of treatment failure in the other half of the patients is unknown, but viral interference with IFNalpha signal transduction through the Jak-STAT pathway might be an important factor. We have shown previously that the expression of HCV proteins leads to an impairment of Jak-STAT signaling because of an inhibition of STAT1 methylation. Unmethylated STAT1 is less active because it can be bound and inactivated by its inhibitor, protein inhibitor of activated STAT1 (PIAS1). We show that treating cells with S-adenosyl-L-methionine (AdoMet) and betaine could restore STAT1 methylation and improve IFNalpha signaling. Furthermore, the antiviral effect of IFNalpha in cell culture could be significantly enhanced by the addition of AdoMet and betaine. In conclusion, we propose that the addition of these drugs to the standard therapy of patients with chronic hepatitis C could overcome treatment resistance.

Dietary choline and betaine assessed by food-frequency questionnaire in relation to plasma total homocysteine concentration in the Framingham Offspring Study

BACKGROUND

Epidemiologic studies of choline and betaine intakes have been sparse because a food-composition database was not available until recently. The physiologic relevance of a variation in dietary choline and betaine in the general population and the validity of intake assessed by food-frequency questionnaire (FFQ) have not been evaluated.

OBJECTIVE

This study was conducted to examine the physiologic relevance and validity of choline and betaine intakes measured by an FFQ.

DESIGN

We examined the relations between choline and betaine intakes measured by FFQ and plasma total homocysteine (tHcy) concentrations in 1960 participants from the Framingham Offspring Study.

RESULTS

Higher intakes of dietary choline and betaine were related to lower tHcy concentrations independent of other determinants, including folate and other B vitamins. For the lowest and highest quintiles of dietary choline plus betaine, the multivariate geometric means for tHcy were 10.9 and 9.9 mumol/L (P for trend < 0.0001). The inverse association was manifested primarily in participants with low folate intakes (P for interaction < 0.0001). Among participants with folate intakes < or =250 microg/d, the geometric mean tHcy concentrations in the lowest and highest quintiles of choline plus betaine intakes were 12.4 and 10.2 micromol/L (P for trend < 0.0001). Except for choline from phosphatidylcholine, individual forms of choline were inversely associated with tHcy concentrations.

CONCLUSIONS

Our findings provide support for a physiologically important variation in choline and betaine intakes in the general population and for the validity of intake measured by FFQ.

[Insulin resistance/hyperinsulinemia associated diseases not included in the metabolic syndrome]

In the past years, in Brazil and in developed countries, obesity has become a major public health problem. It was identified that besides DM2 and metabolic syndrome other clinical entities were associated with insulin resistance. In this review we describe some of these alterations emphasizing nonalcoholic fatty liver disease, but also including polycistic ovary disease, hyperuricemia, chronic renal failure, heart failure, cognitive decline and cancer.

Nonalcoholic fatty liver disease

NAFLD likely is the most common liver disease in children and is responsible for significant progression to cirrhosis, portal hypertension, and the need for liver transplantation in adults and even in some adolescents. Early diagnosis and lifestyle interventions appear to be our best hope for controlling progression of disease. The pediatrician is responsible for screening all obese children with measurement of aminotransferases. Those with elevated enzymes (particularly ALT) for longer than 3 months, in the absence of markers of hepatitis B or C, autoimmune chronic active hepatitis, Wilson's disease, hemochromatosis, or alpha-1-antitrypsin deficiency, should follow up with an abdominal ultrasound. In patients with a BMI in the morbidly obese range, an ultrasound to search for a diffusely echogenic liver should be performed even if the liver enzymes are normal. Findings suggestive of NAFLD should prompt the institution of appropriate dietary and exercise regimens. If these are unsuccessful after a 3-month trial, the patient should be referred to a pediatric gastroenterologist and hepatologist for further work-up and treatment, preferably in the context of a controlled therapeutic trial. Only by aggressively engaging this current epidemic will we be able to decrease the mounting human cost of NAFLD.

Pathophysiological basis for antioxidant therapy in chronic liver disease

Oxidative stress is a common pathogenetic mechanism contributing to initiation and progression of hepatic damage in a variety of liver disorders. Cell damage occurs when there is an excess of reactive species derived from oxygen and nitrogen, or a defect of antioxidant molecules. Experimental research on the delicately regulated molecular strategies whereby cells control the balance between oxidant and antioxidant molecules has progressed in recent years. On the basis of this evidence, antioxidants represent a logical therapeutic strategy for the treatment of chronic liver disease. Clinical studies with large numbers of patients have not yet been performed. However, results from several pilot trials support this concept and indicate that it may be worth performing multicentre studies, particularly combining antioxidants with anti-inflammatory and/or antiviral therapy. Oxidative stress plays a pathogenetic role in liver diseases such as alcoholic liver disease, chronic viral hepatitis, autoimmune liver diseases and non-alcoholic steatohepatitis. The use of antioxidants (e.g. S-adenosylmethionine [SAMe; ademetionine], tocopherol [vitamin E], polyenylphosphatidylcholine or silymarin) has already shown promising results in some of these pathologies.

Nonalcoholic fatty liver disease: from steatosis to cirrhosis

Nonalcoholic steatohepatitis (NASH), the lynchpin between steatosis and cirrhosis in the spectrum of nonalcoholic fatty liver disorders (NAFLD), was barely recognized in 1981. NAFLD is now present in 17% to 33% of Americans, has a worldwide distribution, and parallels the frequency of central adiposity, obesity, insulin resistance, metabolic syndrome and type 2 diabetes. NASH could be present in one third of NAFLD cases. Age, activity of steatohepatitis, and established fibrosis predispose to cirrhosis, which has a 7- to 10-year liver-related mortality of 12% to 25%. Many cases of cryptogenic cirrhosis are likely endstage NASH. While endstage NAFLD currently accounts for 4% to 10% of liver transplants, this may soon rise. Pathogenic concepts for NAFLD/NASH must account for the strong links with overnutrition and underactivity, insulin resistance, and genetic factors. Lipotoxicity, oxidative stress, cytokines, and other proinflammatory mediators may each play a role in transition of steatosis to NASH. The present "gold standard" management of NASH is modest weight reduction, particularly correction of central obesity achieved by combining dietary measures with increased physical activity. Whether achieved by "lifestyle adjustment" or anti-obesity surgery, this improves insulin resistance and reverses steatosis, hepatocellular injury, inflammation, and fibrosis. The same potential for "unwinding" fibrotic NASH is indicated by studies of the peroxisome proliferation activator receptor (PPAR)-gamma agonist "glitazones," but these agents may improve liver disease at the expense of worsening obesity. Future challenges are to approach NAFLD as a preventive public health initiative and to motivate affected persons to adopt a healthier lifestyle.

Mitochondrial dysfunction in NASH: causes, consequences and possible means to prevent it

Calorie-enriched diet and lack of exercise are causing a worldwide surge of obesity, insulin resistance and lipid accretion in liver (i.e. hepatic steatosis), which can lead to steatohepatitis. Steatosis and nonalcoholic steatohepatitis (NASH) can also be induced by drugs such as amiodarone, tamoxifen and some antiretroviral drugs, including stavudine and zidovudine. There is accumulating evidence that mitochondrial dysfunction (more particularly respiratory chain deficiency) plays a key role in the physiopathology of NASH whatever its initial cause. In contrast, the mitochondrial beta-oxidation of fatty acids can be either increased (as in insulin resistance-associated NASH) or decreased (as in drug-induced NASH). However, in both circumstances, generation of reactive oxygen species (ROS) by the damaged respiratory chain can be augmented. ROS generation in an environment enriched in lipids in turn induces lipid peroxidation which releases highly reactive aldehydic derivatives (e.g. malondialdehyde) that have diverse detrimental effects on hepatocytes and other hepatic cells. In hepatocytes, ROS, reactive nitrogen species and lipid peroxidation products further impair the respiratory chain, either directly or indirectly through oxidative damage to the mitochondrial genome. This consequently leads to the generation of more ROS and a vicious cycle occurs. Mitochondrial dysfunction can also lead to apoptosis or necrosis depending on the energy status of the cell. ROS and lipid peroxidation products also increase the generation of several cytokines (TNF-alpha, TGF-beta, Fas ligand) playing a key role in cell death, inflammation and fibrosis. Recent investigations have shown that some genetic polymorphisms can significantly increase the risk of steatohepatitis and that several drugs can prevent or even reverse NASH. Interestingly, most of these drugs could exert their beneficial effects by improving directly or indirectly mitochondrial function in liver. Finding a drug, which could fully prevent oxidative stress and mitochondrial dysfunction in NASH is a major challenge for the next decade.

Review article: Drug therapy for non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease represents a spectrum of liver diseases, characterized mainly by macrovesicular steatosis in the absence of significant alcohol ingestion. Non-alcoholic fatty liver disease includes both non-alcoholic fatty liver and non-alcoholic steatohepatitis. Non-alcoholic steatohepatitis once considered a benign process is now known to lead to progressive fibrosis and cirrhosis. Histologically indistinguishable from alcoholic liver disease, the exact aetiology of non-alcoholic fatty liver disease remains unknown, but the fundamental pathophysiological process appears to be insulin resistance and oxidative stress related to the metabolic syndrome. Therapy has focused on risk factors, weight reduction and pharmacological intervention. Promising pharmacological treatments have been demonstrated with antioxidants, insulin sensitizers, hepatoprotectants and lipid-lowering agents. However, without larger randomized studies, no pharmacological treatments can be recommended at this time.

Liver disease in patients with diabetes mellitus

Diabetes mellitus is a growing health concern in our society. In addition to the well-known cardiovascular, renal, and ophthalmologic complications of diabetes, liver-related complications occur commonly and are often underrecognized. The ensuing article will review the relationship between diabetes mellitus and two common liver diseases: chronic hepatitis C and nonalcoholic fatty liver disease. The association with diabetes and cirrhosis, acute liver failure, hepatocellular carcinoma, and outcomes following orthotopic liver transplantation will also be discussed.

Role of elevated S-adenosylhomocysteine in rat hepatocyte apoptosis: protection by betaine

Previous studies from our laboratory have shown that ethanol consumption results in an increase in hepatocellular S-adenosylhomocysteine levels. Because S-adenosylhomocysteine is a potent inhibitor of methylation reactions, we propose that increased intracellular S-adenosylhomocysteine levels could be a major contributor to ethanol-induced pathologies. To test this hypothesis, hepatocytes isolated from rat livers were grown on collagen-coated plates in Williams' medium E containing 5% FCS and exposed to varying concentrations of adenosine in order to increase intracellular S-adenosylhomocysteine levels. We observed increases in caspase-3 activity following exposure to adenosine. This increase in caspase activity correlated with increases in intracellular S-adenosylhomocysteine levels and DNA hypoploidy. The adenosine-induced changes could be significantly attenuated by betaine administration. The mechanism of betaine action appeared to be via the methylation reaction catalyzed by betaine-homocysteine-methyltransferase. To conclude, our results indicate that the elevation of S-adenosylhomocysteine levels in the liver by ethanol is a major factor in altering methylation reactions and in increasing apoptosis in the liver. We conclude that ethanol-induced alteration in methionine metabolic pathways may play a crucial role in the pathologies associated with alcoholic liver injury and that betaine administration may have beneficial therapeutic effects.

Therapieoptionen für die nicht-alkoholinduzierte Fettleber und Fettleberhepatitis

Nonalcoholic fatty liver disease (NAFLD) is increasingly recognized as one of the most common causes of chronic liver damage in the western world. It is strongly associated with insulin resistance, obesity and other features of the metabolic syndrome. The entity NAFLD embraces a clinical spectrum from benign steatosis over steatohepatitis to hepatic cirrhosis with its complications liver failure and hepatocellular carcinoma. Treatment is currently based on prescriptive diet and physical exercise. A well-defined pharmacotherapy of NAFLD still remains to be established due to the lack of randomized, controlled trials. Yet, for several drugs such as Metformin and Thiazolidinediones, smaller trials report promising results.

Treatment strategies in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized health problem. Increased fat accumulation in the liver is observed in 20-30% of the population in the Western world, and in approximately 10% of this cohort it is associated with nonalcoholic steatohepatitis, which is characterized by inflammation and fibrosis. Disease presentation of NAFLD ranges from asymptomatic disease to cirrhosis with the complication of liver failure and hepatocellular carcinoma. NAFLD is suspected on the basis of various clinical aspects (an elevated alanine aminotransferase concentration, presence of obesity and diabetes) that alone are not sufficient to establish diagnosis or prognosis. The major diagnostic procedure is liver biopsy, which allows assessment of liver injury. In most cases, NAFLD is associated with insulin resistance, which is therefore the target of most current NAFLD treatment modalities. Various treatment strategies such as weight loss and/or exercise, thiazolidinediones, metformin, lipid-lowering agents and antioxidants have been studied. So far, no single intervention has convincingly improved liver histology. It is recommended that patients at high risk of developing advanced liver disease, and who are not part of controlled studies, should receive nutritional counseling and take physical exercise to achieve moderate weight loss and improve insulin sensitivity.

Phosphatidylcholine homeostasis and liver failure

In mammals, the only endogenous pathway for choline biosynthesis is the methylation of phosphatidylethanolamine to phosphatidylcholine (PC) by phosphatidylethanolamine N-methyltransferase (PEMT) coupled to PC degradation. Complete choline deprivation in mice by feeding Pemt(-/-) mice a choline-deficient (CD) diet decreases hepatic PC by 50% and is lethal within 5 days. PC secretion into bile is mediated by a PC-specific flippase, multiple drug-resistant protein 2 (MDR2). Here, we report that mice that lack both PEMT and MDR2 and are fed a CD diet survive for >90 days. Unexpectedly, the amount of PC also decreases by 50% in the livers of Mdr2(-/-)/Pemt(-/-) mice. The Mdr2(-/-)/Pemt(-/-) mice adapt to the severe choline deprivation via choline recycling by induction of phospholipase A(2), choline kinase, and CTP:phosphocholine cytidylyltransferase activities and by a strikingly decreased expression of choline oxidase. The ability of Mdr2(-/-)/Pemt(-/-) mice to survive complete choline deprivation suggests that acute lethality in CD-Pemt(-/-) mice results from rapid depletion of hepatic PC via biliary secretion.

Approach to the diagnosis and treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease in the United States. It describes several clinicopathologic entities from simple hepatic steatosis to nonalcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma. This article describes the epidemiology, clinical features, natural history, and pathogenesis of NAFLD.

Nonalcoholic fatty liver disease in the pediatric population: a review

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease is a common condition that may progress to end stage liver disease. It is closely associated with obesity and insulin resistance, two conditions whose prevalence is increasing dramatically in children. This could potentially make nonalcoholic fatty liver disease the most common liver disease in the pediatric population. This review will focus on the current knowledge regarding the epidemiology, clinical presentation, diagnosis, pathogenesis, and management of nonalcoholic fatty liver disease in children.

RECENT FINDINGS

Recent studies suggest that nonalcoholic fatty liver disease is an increasingly recognized condition during childhood, especially in overweight and obese children. Although limited information is currently available on the natural history of the disease in the pediatric population, few cross-sectional studies and a single longitudinal cohort study with follow up data up to 16 years, showed that as in adults, nonalcoholic fatty liver disease in children may have a progressive clinical course with the development of cirrhosis. Emerging data from small pilot studies suggest weight loss through lifestyle modifications as well as insulin sensitizing and antioxidant medications may be of benefit. Moreover, recent advances in the understanding of nonalcoholic fatty liver disease pathogenesis may result in novel therapeutic targets to treat this disease.

SUMMARY

Nonalcoholic fatty liver disease is probably the most common form of chronic liver disease in children and may continue to rise with the increasing prevalence of childhood obesity and metabolic syndrome. Recent studies have provided new insights regarding this condition in children. There is still much progress to be made in terms of the description of pediatric nonalcoholic fatty liver disease, its demographics, pathogenesis, and treatment as well as natural history and long-term prognosis.

Mechanisms of liver fibrosis

Liver fibrosis represents a significant health problem worldwide of which no acceptable therapy exists. The most characteristic feature of liver fibrosis is excess deposition of type I collagen. A great deal of research has been performed to understand the molecular mechanisms responsible for the development of liver fibrosis. The activated hepatic stellate cell (HSC) is the primary cell type responsible for the excess production of collagen. Following a fibrogenic stimulus, HSCs change from a quiescent to an activated, collagen-producing cell. Numerous changes in gene expression are associated with HSC activation including the induction of several intracellular signaling cascades, which help maintain the activated phenotype and control the fibrogenic and proliferative state of the cell. Detailed analyses in understanding the molecular basis of collagen gene regulation have revealed a complex process offering the opportunity for multiple potential therapeutic strategies. However, further research is still needed to gain a better understanding of HSC activation and how this cell maintains its fibrogenic nature. In this review we describe many of the molecular events that occur following HSC activation and collagen gene regulation that contribute to the fibrogenic nature of these cells and provide a review of therapeutic strategies to treat this disease.

Thymosin alpha 1 attenuates lipid peroxidation and improves fructose-induced steatohepatitis in rats

OBJECTIVES

The aim of this study was to investigate the effects of thymosin alpha(1) (Talpha(1)) in rats having fructose-induced steatosis. Fructose leads to experimental steatosis in the liver by exerting its effect on some components of the oxidant/antioxidant system, and on several cytokines (interleukin-1beta, -2, and -6) in blood.

METHODS

Twenty-four rats at random were divided into three groups (each group containing eight animals); the control group (C), which received a purified diet; the high-fructose-fed group (F); and the high-fructose-fed and Talpha(1) injected group (F + T). After the experimental period of 10 days, liver lipid peroxidation and antioxidant status, and blood IL-1beta, IL-2, and IL-6 levels were quantified.

RESULTS

In comparison with the C group, the F group had a higher nitric oxide (NO) level, xanthine oxidase (XO) activity, and lipid peroxidation, as indicated by concentrations of thiobarbituric acid reactive substances (TBARS), and lower superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the liver. In the F + T group, these markers were near the values of the control group. In addition, increased IL-1beta and IL-6 levels were kept at near to normal levels with treatment of Talpha(1), but not IL-2 levels. In the F group, the most consistent findings in the histologic sections of liver tissues were the macrovesicular and microvesicular steatosis. Talpha(1) treatment protected the majority of the liver cells, while minimal macrovesicular and microvesicular steatosis was observed in the remaining cells.

CONCLUSIONS

These results show that a high-fructose diet in rats leads to hepatic steatosis and a defect in the free radical defense system, and that treatment of Talpha(1) may improve these biochemical and morphologic changes in the fructose-fed rat livers.

Management of dyslipidemia in patients with complicated metabolic syndrome

As the prevalence of the metabolic syndrome increases, 2 comorbid conditions--hepatic steatosis and human immunodeficiency virus (HIV) lipodystrophy--have become difficult clinical challenges. Dyslipidemia in patients with nonalcoholic fatty liver disease or nonalcoholic steatohepatitis may improve with use of statins, fibrates, niacin, and thiazolidinediones, but the data are presently very limited. HIV lipodystrophy is associated with a marked risk of coronary artery disease (CAD), and more aggressive management of the dyslipidemia is likely necessary to improve the prognosis.

Nonalcoholic fatty liver disease: a review

Nonalcoholic fatty liver disease is an umbrella term that includes steatosis, nonalcoholic steatohepatitis and advanced fibrosis or cirrhosis. The terminology, although cumbersome, was intended to differentiate these disorders from alcohol-related liver disorders, as they are histologically similar. The term was first used by Ludwig in 1980, but has received a tremendous amount of attention in the past several years as a result of a better understanding of the scope of the problem. Although the pathogenesis has not been fully elucidated, there is a tremendous amount of research ongoing in this arena, both clinical and basic, to determine how the course of the disease can be altered. This text reviews the epidemiology of the disease, leading theories of pathogenesis, and treatment options.

Nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease is emerging as the most common chronic liver condition in the Western world. It is associated with insulin resistance and frequently occurs with features of the metabolic syndrome. Disease presentation ranges from asymptomatic elevated liver enzyme levels to cirrhosis with complications of liver failure and hepatocellular carcinoma. Current treatment recommendations are limited to weight loss and exercise, although several promising medications are on the horizon. In this article we discuss the etiology, pathogenesis and diagnosis of nonalcoholic fatty liver disease as well as approaches to its management.

Therapeutic strategies in nonalcoholic fatty liver disorders

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder in developing countries. Many of the risk factors are well defined, but the underlying pathogenesis is not well understood. The demographics of the condition mirror those of the metabolic syndrome, with obesity and insulin resistance being the most commonly associated conditions. At present, therapy is aimed at correcting the risk factors, but there are no proven therapies at this point.

Effects of betaine supplementation on hepatic metabolism of sulfur-containing amino acids in mice

BACKGROUND/AIMS

We previously reported that acute betaine treatment induced significant changes in the hepatic glutathione and cysteine levels in mice and rats. The present study was aimed to determine the effects of dietary betaine on the metabolism of sulfur-containing amino acids.

METHODS/RESULTS

Male mice were supplemented with betaine (1%) in drinking water for up to 3 weeks. Changes in hepatic levels of major sulfur amino acid metabolites and products were stabilized after 2 weeks of betaine supplementation. Betaine intake increased methionine, S-adenosylmethionine, and S-adenosylhomocysteine levels significantly, but homocysteine and cystathionine were reduced. Methionine adenosyltransferase activity was elevated to three-fold of control. Cysteine catabolism to taurine was inhibited as evidenced by a decrease in cysteine dioxygenase activity and taurine levels in liver and plasma. Despite the significant changes in the transsulfuration reactions, neither hepatic cysteine nor glutathione was altered. Betaine supplementation decreased the hepatotoxicity induced by chloroform (0.5 ml/kg, ip) significantly.

CONCLUSIONS

Betaine supplementation enhances recycling of homocysteine for the generation of methionine and S-adenosylmethionine while reducing its utilization for the synthesis of cystathionine and cysteine. However, the hepatic levels of cysteine or glutathione are not affected, most probably due to the depression of taurine generation from cysteine.

Tratamiento médico de la hepatopatía grasa no alcohólica primaria

The need for an effective and safe medical treatment of nonalcoholic fatty liver disease is urgent due to its high prevalence and progressive character. At the moment, therapeutic strategies are largely empirical and based on the control of associated clinical conditions (especially obesity, type 2 diabetes mellitus, and hypertriglyceridemia) and the use of some specific drugs (insulin sensitizing agents, cytoprotectives, antioxidants, and anticytokines) as an attempt to counteract known elements of the pathogenesis. None of these specifics measures have been found to display enough evidence to recommend their clinical use. It is indispensable to join efforts in coordinated networks to define, as soon as possible, the best treatment and the best time to start it.

Effects of emodin on treating murine nonalcoholic fatty liver induced by high caloric laboratory chaw

AIM: To investigate the effects of emodin on the treatment of non-alcoholic fatty liver in rats induced by high caloric laboratory chaw.

METHODS: Non-alcoholic fatty liver model was successfully established by feeding with high caloric laboratory chaw for 12 wk. Then the model rats were randomly divided into 3 groups, namely model control group, emodin group and dietary treatment group. The rats in emodin group were given emodin at dose of 40 mg/(kg·d) while animals in other groups were given distilled water of the same volume. The rats in model control group were fed with high caloric laboratory chaw while animals in other groups were fed with normal diet. Four weeks later, liver index (liver/body weight ratio), serum activities of liver-associated enzymes, blood lipid, fasting blood glucose, fasting plasma insulin, HOMA insulin resistance index (HOMA-IR), hepatic triglyceride content and histology features of all groups were assayed. The expression of hepatic peroxisomal proliferator activated receptor (PPAR) gamma was determined by RT-PCR.

RESULTS: The body weight, liver index, serum activities of alanine aminotransferase (ALT), blood lipid, hepatic triglyceride content of model control group were significantly elevated, with moderate to severe hepatocyte steatosis. The expression of hepatic PPAR gamma mRNA was obviously reduced in model control group. Compared with model control group, the body weight, liver index, serum activities of ALT, blood lipids and hepatic triglyceride of emodin group significantly decreased and hepatic histology display was also greatly improved. Meanwhile, the expression of hepatic PPAR gamma mRNA was elevated. However, high serum activities of ALT and hyperlipidemia were persisted in dietary treatment group although liver index was decreased and liver histology was somewhat improved.

CONCLUSION: It is suggested that emodin might be effective in the treatment of non-alcoholic fatty liver in rats. Its therapeutic mechanism could be associated with increasing the expression of hepatic PPAR gamma mRNA.

Hepatic complications of obesity

Obesity increases the risk and severity of liver disease. The most common form of liver disease that occurs in obesity is NAFLD. A better understanding of the basic disease mechanisms and natural histories ofNAFLD is needed to guide management and treatment of obese patients and others with this disorder. Large, prospective, randomized, controlled treatment trials also are needed. Ideally, such studies will focus on well-defined patient subsets and monitor the impact of therapy on clinically relevant endpoints, such as liver-related morbidity and mortality.

Nonalcoholic steatohepatitis: recent advances from experimental models to clinical management

A condition defined as nonalcoholic fatty liver disease (NAFLD) is frequently found in humans. Deemed as a benign condition until recently, more emphasis is now put on the potential harmful evolution of the inflammatory form, that is, nonalcoholic steatohepatitis (NASH), toward end-stage liver disease. This review highlights the major morphologic and pathophysiological features of NASH. The link between experimental biochemical findings in animal models and clinical and therapeutic approaches in humans is discussed. Once all the other causes of persistent elevation of serum transaminase levels have been excluded, the diagnosis of NASH can be only confirmed by liver histology. Other noninvasive diagnostic tools, however, are being investigated to assess specific subcellular functions and to allow the follow-up of patients at higher risk for major liver dysfunction. A better understanding of various pathogenic aspects of NASH will help in identifying potential therapeutic approaches in these patients.

Levels of serum vitamin A, alpha-tocopherol and malondialdehyde in patients with non-alcoholic steatohepatitis: relationship with histopathologic severity

The aims of our study were to estimate serum levels of malondialdehyde (MDA), serum levels of vitamin A and alpha-tocopherol as antioxidants and determine relationship of these with histopathologic severity in patients with non-alcoholic steatohepatitis (NASH). Twenty-nine patients with biopsy-proven NASH were included to study. NASH were histopathologically scored for grading and staging. Serum MDA and vitamin A levels were increased in patients with NASH and simple steatosis as compared to healthy control group. Serum alpha-tocopherol levels measured in simple steatosis and NASH were significantly lower than in healthy control group. There was no significant difference between grade/stage 0-1 and grade/stage 2-3 in terms of MDA, vitamin A and alpha-tocopherol levels. Serum MDA and vitamin A levels are increased in simple steatosis and NASH. MDA, vitamin A and alpha-tocopherol levels in NASH were not associated with the histopathologic severity.

Nonalcoholic fatty liver disease: a clinical review

Nonalcoholic fatty liver disease may be the most common liver disease in the United States, with a high prevalence in the obese, type 2 diabetic population, and it is probably underestimated as a cause for cirrhosis. Clinicopathologically, it represents a wide spectrum of histologic abnormalities and clinical outcomes, ranging from benign hepatic steatosis to cirrhosis. Pathophysiologically, insulin resistance is thought to be pivotal in the development of steatosis, after which a second oxidative stressor produces lipid peroxidation and nonalcoholic steatohepatitis (NASH). Liver biopsy is the gold standard for diagnosis and prognosis. The need for an effective treatment is both clear and urgent, yet in the absence of proven therapies, treatment is directed toward weight loss and comorbidity management. For patients with NAFLD at risk of disease progression, there is a lack of large, randomized, placebo-controlled trials of adequate treatment duration, with baseline stratification according to histologic severity.

Non-alcoholic steatohepatitis in children

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.

Nonalcoholic fatty liver disease: a review of current understanding and future impact

Nonalcoholic fatty liver disease (NAFLD), already the most common form of liver disease in the United States, can be expected to increase in prevalence and severity in parallel with national epidemics of obesity and type 2 diabetes. NAFLD is frequently associated with insulin resistance. While insulin resistance, and thereby hyperinsulinemia, are, in large part, metabolic consequences of obesity, the basis of diversity in severity and progression of inflammation and fibrosis is not known. Increased susceptibility to oxidative stress is likely to play a role. Several patient characteristics have been associated with more severe histological findings in patients with NAFLD, including type 2 diabetes, hypertension, age over 40 years, and higher transaminases. Liver biopsy is, however, required to accurately grade and stage NAFLD histologically. Although the natural history of NAFLD is relatively poorly defined, NAFLD is increasingly recognized as an important cause of decompensated liver disease. Weight reduction and improved insulin sensitivity are associated with improved biochemical and histological parameters of NAFLD. There are, however, no proven safe and efficacious pharmacological treatments for NAFLD.

Nonalcoholic Steatohepatitis

Nonalcoholic steatohepatitis (NASH) is an important medical condition and there is great public health concern related to its increasing incidence and potential implications for the development of end-stage liver disease. NASH represents a progression beyond simple lipid deposition in the liver parenchyma, requiring histologic evidence for hepatocyte injury such as ballooning degeneration, Mallory bodies, and/or pericellular fibrosis that can potentially lead to progressive liver injury and eventually cirrhosis. It is believed that several insults contribute to the evolution of hepatic injury such as insulin dysregulation, lipid deposition, oxidative free radicals, and lipid perioxidation. Initial treatment protocols for NASH focus on various aspects of injury in an attempt to control insulin imbalances, improve lipid regulation, reduce free radicals, and ameliorate the inflammatory process. No therapy is conclusively beneficial in all individuals, but preliminary data suggest several approaches that hold promise.

Oxidative Stress in Nonalcoholic Fatty Liver Disease: Pathogenesis and Antioxidant Therapies

Nonalcoholic fatty liver disease is a common cause of chronic liver disease, a common finding on liver biopsy in those patients with abnormal blood transaminase levels, and a common cause of cryptogenic cirrhosis in the United States. The prevalence of this disorder is expected to rise with the increase in obesity, and the clinical spectrum can range from simple steatosis (fatty liver) to cirrhosis of the liver. Insulin resistance is thought to be pivotal for the development of steatosis, and oxidative stress may be a potential factor that can promote hepatic necroinflammation and fibrosis. Preliminary studies have examined the role of oxidative stress and antioxidants in animal and human studies of this disorder. Efforts to improve the hepatic antioxidant system could be achieved by optimizing the patient's diet, by supplementation with precursors for antioxidants, or by supplementation with essential metals and/or antioxidants. Randomized, controlled trials are required to examine these potential approaches using patients with this disorder.

Non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is an underdiagnosed liver disease characterized by steatosis, necroinflammation and fibrosis. This disease may eventually develop into cirrhosis and hepatocellular carcinoma. NASH is highly prevalent among obese individuals and among patients with diabetes mellitus type 2. Non-alcoholic fatty liver (NAFL), a precursor of NASH, is the main cause of elevated serum liver enzymes among the general population. In NASH the liver is programmed to lipogenesis rather than to glycogenesis and herein insulin-resistance plays a major role. Gradual weight loss, physical exercise and drugs that improve insulin sensitivity are potential therapies.

Nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is a well-recognized form of chronic liver disease affecting both children and adults that has gained increased recognition. Recently NAFLD has been associated with insulin resistance and its incidence and prevalence is likely increasing, paralleling the rise in obesity and diabetes mellitus in the United States. The article includes current thoughts on the natural history and pathogenesis of NAFLD and describes current trends in the diagnosis and treatment of this condition.

Beneficial effects of tumor necrosis factor-alpha inhibition by pentoxifylline on clinical, biochemical, and metabolic parameters of patients with nonalcoholic steatohepatitis

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) has been incriminated to play an important role in the pathogenesis of nonalcoholic steatohepatitis (NASH). Pentoxifylline, a TNF-alpha inhibitor could prove useful in treating patients with NASH.

METHODS

Eighteen patients (mean age, 34 +/- 7.8 yr) with histologically proven NASH and with persistently elevated ALT (>1.5 times) were given pentoxifylline at a dosage of 400 mg t.i.d. for 6 months. No lipid-lowering agent or antioxidants were concurrently advised.

RESULTS

Impaired fasting glycemia, impaired glucose tolerance, diabetes mellitus, and hypertriglyceridemia were noted in 6, 35, 17, and 53% of the patients, respectively. After 6 months of therapy, fatigue improved (55.6 vs 20%, p= 0.016), but serum triglyceride (182 +/- 66 vs 160 +/- 55 mg/dl, p= 0.397), cholesterol (173 +/- 46 vs 162 +/- 40 mg/dl, p= 0.440), and body mass index (BMI) (27.3 +/- 3.1 vs 26 +/- 3.1 kg/m(2), p= 0.087) remained unchanged. Mean AST (66 +/- 29 vs 33 +/- 11 IU/l, p < 0.0001) and ALT (109 +/- 44 vs 47 +/- 20 IU/l, p < 0.0001) reduced significantly. ALT normalized in 23% at month 1 (p= 0.125), 35% at month 2 (p= 0.125), and 60% at month 6 (p= 0.008) of treatment. The insulin resistance index assessed by homeostatic metabolic assessment (HOMA(IR)) improved (5.1 +/- 3.4 vs 2.6 +/- 2, p = 0.046) and the serum TNF-alpha reduced significantly after therapy (22.15 +/- 2.49 vs 17 +/- 2.58 pg/ml, p = 0.011). The drug was well tolerated.

CONCLUSIONS

In patients with NASH, pentoxifylline therapy effectively achieved significant clinical and biochemical improvement with reduction in HOMA(IR). These benefits are possibly mediated through suppression of TNF-alpha.

Betaine in human nutrition

Betaine is distributed widely in animals, plants, and microorganisms, and rich dietary sources include seafood, especially marine invertebrates ( approximately 1%); wheat germ or bran ( approximately 1%); and spinach ( approximately 0.7%). The principal physiologic role of betaine is as an osmolyte and methyl donor (transmethylation). As an osmolyte, betaine protects cells, proteins, and enzymes from environmental stress (eg, low water, high salinity, or extreme temperature). As a methyl donor, betaine participates in the methionine cycle-primarily in the human liver and kidneys. Inadequate dietary intake of methyl groups leads to hypomethylation in many important pathways, including 1) disturbed hepatic protein (methionine) metabolism as determined by elevated plasma homocysteine concentrations and decreased S-adenosylmethionine concentrations, and 2) inadequate hepatic fat metabolism, which leads to steatosis (fatty accumulation) and subsequent plasma dyslipidemia. This alteration in liver metabolism may contribute to various diseases, including coronary, cerebral, hepatic, and vascular diseases. Betaine has been shown to protect internal organs, improve vascular risk factors, and enhance performance. Databases of betaine content in food are being developed for correlation with population health studies. The growing body of evidence shows that betaine is an important nutrient for the prevention of chronic disease.

Mechanisms of non-alcoholic steatohepatitis

In 1980, the term non-alcoholic steatohepatitis was coined to describe a new syndrome occurring in patients who usually were obese (often diabetic) females who had a liver biopsy picture consistent with alcoholic hepatitis, but who denied alcohol use. The causes of this syndrome were unknown, and there was no defined therapy. More than two decades later, this clinical syndrome is only somewhat better understood, and still there is no Food and Drug Administration-approved or even generally accepted drug therapy. Patients with primary non-alcoholic steatohepatitis typically have the insulin resistance syndrome (synonymous with the metabolic syndrome, syndrome X, and so forth), which is characterized by obesity, diabetes, hyperlipidemia, hypertension, and, in some instances, other metabolic abnormalities such as polycystic ovary disease. Secondary non-alcoholic steatohepatitis may be caused by drugs such as tamoxifen, certain industrial toxins, rapid weight loss, and so forth. The cause of non-alcoholic steatohepatitis remains elusive, but most investigators agree that a baseline of steatosis requires a second hit capable of inducing inflammation, fibrosis, or necrosis for non-alcoholic steatohepatitis to develop. Our research group has focused its efforts on the interactions of nutritional abnormalities, cytokines, oxidative stress with lipid peroxidation, and mitochondrial dysfunction in the induction of steatohepatitis, both alcoholic and non-alcoholic in origin. Research findings from other laboratories also support the role of increased cytokine activity, oxidative stress, and mitochondrial dysfunction in the pathogenesis of non-alcoholic steatohepatitis. The objectives of this article are to review the (1) definition and clinical features of non-alcoholic steatohepatitis, (2) potential mechanisms of non-alcoholic steatohepatitis, and (3) potential therapeutic interventions in non-alcoholic steatohepatitis.

Management of nonalcoholic fatty liver disease: weight control

With obesity reaching epidemic proportions in the United States, it is imperative that hepatologists have an understanding of the medical ramifications and methods of treatment. Evaluation of nonalcoholic fatty liver disease may get the patient into the office,but weight reduction may provide a therapeutic hurdle. This article provides an overview of current obesity treatment.

Approach to the pathogenesis and treatment of nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) represents an advanced stage of fatty liver disease developed in the absence of alcohol abuse. Its increasing prevalence in western countries, the diagnostic difficulties by noninvasive tests, and the possibility of progression to advanced fibrosis and even cirrhosis make NASH a challenge for hepatologists. NASH is frequently associated with type 2 diabetes and the metabolic syndrome, and several genetic and acquired factors are involved in its pathogenesis. Insulin resistance plays a central role in the development of a steatotic liver, which becomes vulnerable to additional injuries. Several cyclic mechanisms leading to self-enhancement of insulin resistance and hepatic accumulation of fat have been recently identified. Excess intracellular fatty acids, oxidant stress, tumor necrosis factor-alpha, and mitochondrial dysfunction are causes of hepatocellular injury, thereby leading to disease progression and to the establishment of NASH. Intestinal bacterial overgrowth also plays a role, by increasing production of endogenous ethanol and proinflammatory cytokines. Therapeutic strategies aimed at modulating insulin resistance, normalizing lipoprotein metabolism, and downregulating inflammatory mediators with probiotics have promising potential.

Pharmacologic management of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is an emerging epidemic in Western societies, and therapeutic modalities to treat this condition are needed desperately. Most early treatment studies tended to focus on improvement in the serum aminotransferases. Presently, treatment of NAFLD is aimed at improving the underlying steatosis, necroinflammatory activity, and fibrosis because elevations of the aminotransferases may not accurately reflect these important histologic endpoints. Unfortunately, well-defined treatment options are few,which is largely due to limited experience reported in small, prospective pilot trials. This article focuses on the various therapeutic agents that have been evaluated in the treatment of NAFLD and their efficacy as well as their limitations.

Metabolic, antioxidant, nutraceutical, probiotic, and herbal therapies relating to the management of hepatobiliary disorders

Many nutraceuticals, conditionally essential nutrients, and botanical extracts have been proposed as useful in the management of liver disease. The most studied of these are addressed in terms of proposed mechanisms of action, benefits, hazards, and safe dosing recommendations allowed by current information. While this is an area of soft science, it is important to keep an open and tolerant mind, considering that many major treatment discoveries were in fact serendipitous accidents.

The ins and outs of mitochondrial dysfunction in NASH

Rich diet and lack of exercise are causing a surge in obesity, insulin resistance and steatosis, which can evolve into steatohepatitis. Steatosis and nonalcoholic steatohepatitis (NASH) can also be induced by drugs such as amiodarone, tamoxifen and some antiretroviral drugs. There is growing evidence that mitochondrial dysfunction, and more specifically respiratory chain deficiency, plays a role in the pathophysiology of NASH whatever its initial cause. In contrast, the B-oxidation of fatty acids can be either increased (as in insulin resistance-associated NASH) or decreased (as in drug-induced NASH). However, in both circumstances, the generation of reactive oxygen species (ROS) by the damaged respiratory chain is augmented, as components of this chain are over-reduced by electrons, which then abnormally react with oxygen to form increased amounts of ROS. Concomitantly, ROS oxidize fat deposits to release lipid peroxidation products that have detrimental effects on hepatocytes and other hepatic cells. In hepatocytes, ROS and lipid peroxidation products further impair the respiratory chain, either directly or indirectly through oxidative damage to the mitochondrial genome. This, in turn, leads to the generation of more ROS and a vicious cycle ensues. Mitochondrial dysfunction can also lead to apoptosis or necrosis depending on the energy status of the cell. ROS and lipid peroxidation products also activate stellate cells, thus resulting in fibrosis. Finally, ROS and lipid peroxidation increase the generation of several cytokines (TNF-alpha, TGF-B, Fas ligand) that play sundry roles in the pathogenesis of NASH. Recent investigations have shown that some genetic polymorphisms can significantly increase the risk of steatohepatitis and that several drugs can prevent or even reverse NASH. For the next decade, reducing the incidence of NASH will be a major challenge for hepatologists.