Drug-induced fatty liver disease: An overview of pathogenesis and management

Over the past decades, many drugs have been identified, that can potentially induce steatohepatitis in the predisposed individual. Classically this has been incriminated to amiodarone, perhexiline, and 4,4’-diethylaminoethoxyhexestrol (DH), all of which have been found to independently induce the histologic picture of non-alcoholic steatohepatitis (NASH). Pathogenetic mechanisms of hepatotoxicity although still evolving, demonstrate that mitochondrial dysfunction, deranged ATP production and fatty acid catabolism likely play an important role. Drugs like steroid hormones can exacerbate the pathogenetic mechanisms that lead to NASH, and other drugs like tamoxifen, cisplatin and irenotecan have been shown to precipitate latent fatty liver as well. Further research aiming to elucidate the pathogenesis of drug-induced steatosis and steatohepatitis is needed in order to better design therapeutic targets.     

Nonalcoholic steatohepatitis: definition and pathology

Nonalcoholic steatohepatitis (NASH) is a significant form of chronic liver disease in adults and children. The natural history of NASH ranges from indolent to end-stage liver disease. Current studies are focusing on identification of histologic and/or clinical markers of progression. NASH may be an underlying cause of cryptogenic cirrhosis, and the lesions of NASH may recur in allograft livers. An expanding array of clinical conditions and pathogenetic mechanisms have been identified, but many cases remain "idiopathic"; lack of significant alcohol use is, by definition, common to all cases. Neither clinical evaluation nor laboratory values can ensure either the diagnosis or the exclusion of NASH, and liver biopsy interpretation continues to be considered the "gold standard" for diagnosis. The lesions in NASH are similar but not identical to those of alcoholic steatohepatitis; exact, specific histologic criteria for the diagnosis are currently under discussion. The lesions most commonly accepted for NASH include steatosis, hepatocyte ballooning degeneration, mild diffuse lobular mixed acute and chronic inflammation, and perivenular, perisinusoidal collagen deposition. Zone 3 accentuation may be detected. Mallory's hyaline, vacuolated nuclei in periportal hepatocytes, lobular lipogranulomas, and PAS-diastase-resistant Kupffer cells are common. In biopsy specimens from children, portal inflammation may be more prominent than in adults. Progression of fibrosis may result in bridging septa and cirrhosis. The lesions of steatohepatitis may be noted concurrently with other forms of chronic liver disease. A histological "grading and staging" system has been developed to reflect the unique features of steatohepatitis, gradations of severity and fibrosis, and to promote uniform reporting of the histopathology.     

Drugs and steatohepatitis

In addition to the usual associations with insulin resistance, type 2 diabetes, central obesity, and hypertriglyceridemia, nonalcoholic steatohepatitis (NASH) has been associated with several drugs and toxins. However, drug-induced liver disease is a relatively uncommon cause of steatohepatitis. The term drug-induced steatohepatitis is preferred when the association appears to result from a direct toxic effect of the drug on the liver. For some agents implicated as causing cirrhosis or fatty liver disorders, the association may be coincidental because NASH is a common component of the insulin resistance (or metabolic) syndrome. In other instances, corticosteroids, tamoxifen, and estrogens may precipitate NASH in predisposed persons by exacerbating insulin resistance, central obesity, diabetes, and hypertriglyceridemia, and methotrexate may worsen hepatic fibrosis in NASH. Drug-induced steatohepatitis is associated with prolonged therapy (more than 6 months) and possibly drug accumulation, which in the case of perhexiline maleate is favored by a genetic polymorphism of CYP2D6 that leads to slow perhexiline oxidation. The toxic mechanism appears to involve mitochondrial injury, which causes steatosis because of impaired beta-oxidation of fatty acids, and leads to generation of reactive oxygen species and ATP depletion. Thus, drug-induced steatohepatitis may provide clues to injurious events in the more common metabolic forms of NASH. A clinical feature of some types of drug-induced steatohepatitis is progression after discontinuation of the causative agent. It follows that early recognition of hepatotoxicity is crucial to prevent the development of severer forms of liver disease and improve the clinical outcome.     

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.     

The pathology of nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized form of chronic liver injury. Nonalcoholic steatohepatitis (NASH) is the term applied to the microscopically-defined subset of NAFLD with known progression to cirrhosis and the complications that may be associated, including metabolic imbalances, liver failure and hepatocellular carcinoma. NASH is also being considered as a significant precursor of end-stage liver disease, 'cryptogenic cirrhosis', in which the histologic features of the initial liver disease can no longer be appreciated. Because of the increasing prevalence and the known significance of this form of liver disease, current investigations are focused on discerning the clinical features of susceptible patients, the histopathologic findings that characterize the entity and serve as markers of progression, pathogenetic mechanisms that result in triglyceride accumulation, liver injury and fibrosis, and ultimately, treatment options.     

Non-alcoholic steatohepatitis in children

Non-alcoholic steatohepatitis (NASH) is an important liver disease in children; it can cause cirrhosis in children. The disease mechanism involves hepatic insulin resistance with hyperinsulinemia and changes in certain adipocytokines and inflammatory mediators. The differential diagnosis of childhood NASH includes metabolic disorders, drug hepatotoxicity, and alcoholic hepatitis in adolescent patients. The histologic features in childhood NASH often differ from those in adults who have NASH. Treatment is gradual weight loss through changes in food intake patterns and increased levels of physical activity; the role of drug treatment of NASH in children is an area of ongoing research.     

The relevance of liver histology to predicting clinically meaningful outcomes in nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most prevalent chronic liver disease. Nonalcoholic steatohepatitis (NASH), the more severe form of NAFLD, has an increased risk for progression to cirrhosis. The available data suggest increased morbidity and mortality among those patients with advanced histologic severity such as NASH and fibrosis. Despite the lack of a universally accepted histologic definition of NAFLD and inconsistency among pathologists regarding histologic findings essential to the diagnosis of NASH, a few studies have identified specific histologic findings (particularly fibrosis regardless of stage) that are able to predict NAFLD-related mortality as being most important.     

Cross talk of the immune system in the adipose tissue and the liver in non-alcoholic steatohepatitis: Pathology and beyond

Non-alcoholic steatohepatitis(NASH) is considered to be the hepatic manifestation of the metabolic syndrome, thus has a tight correlation with systemic metabolic impairment. The complex mechanisms underlying the pathogenesis of NASH involve different organs and systems that cross talk together contributing to the onset of NASH. A crucial role is played by inflammatory mediators, especially those deriving from the adipose tissue and the liver, which are involved in the cascade of inflammation, fibrosis and eventually tumorigenesis. In this setting cytokines and adipokines as well as immunity are emerging drivers of the key features of NASH. The immune system participates in this process with disturbances of the cells constituting both the innate and the adaptive immune systems that have been reported in different organs, such as in the liver and in the adipose tissue, in clinical and preclinical studies. The role of the immune system in NASH is increasingly studied, not only because of its contribution to the pathogenetic mechanisms of NASH but also because of the new potential therapeutic options it offers in this setting. Indeed, novel treatments acting on the immune system could offer new options in the management of NASH and the correlated clinical consequences.     

Nonalcoholic steatohepatitis, the enigma of bad progression

Still, very little is known about the precise pathogenetic mechanisms, the triggering events and in particular, the evolution and treatment of nonalcoholic steatohepatitis (NASH). It is part of the broad spectrum of nonalcoholic fatty liver diseases (NAFLDs). Mainly, it has been reported as a benign disease, associated with metabolic disorders commonly occurrence en the general population. Nevertheless, the syndrome can lead to cirrhosis, liver failure or hepatocellular carcinoma, requiring liver transplantation. We present one patient with diagnosis of NASH, who was treated initially for overweight, HTA and hyperlipaemia with incompleted response and who showed a quickly progress to cirrhosis but no cause of liver decompensated disease could be identified. Currently she is at end-stage waiting a liver transplantation. Controlled and multicentric studies with the same definition of NASH and the study end-points are needed, and will provide information about diagnosis features and novel therapies to early management of the disease.     

Pathology of nonalcoholic steatohepatitis.

To date, histologic evaluation, most commonly in the form of liver biopsy, remains the gold standard in evaluation of nonalcoholic fatty liver disease (NAFLD). Histologic evaluation was fundamental to the initial studies that introduced and defined the concept of fatty liver as a liver disease. Currently, liver biopsy in NAFLD serves multiple roles: confirmation (or exclusion) of the diagnosis; distinction of steatohepatitis from "simple steatosis"; assessment of extent of necroinflammatory activity, fibrosis, and architectural alterations. Histopathologic studies have underscored the fact that not all obese and/or diabetic individuals with elevated liver tests have fatty liver disease; for example, hepatic glycogenosis and hepatosclerosis have been described in diabetics, and other significant liver diseases have been documented. Likewise biopsy studies have documented lesions of steatosis or steatohepatitis in unusual patient groups or clinical settings, such as lean individuals, individuals with normal liver tests, patients taking certain medications, patients with co-existent serologically-diagnosed liver disease, and pediatric patients. Biopsy studies have shown that the lesions of NASH may or may not persist in cirrhosis; prior evidence of NASH on liver biopsy serves as a benchmark for the concept that many cases of otherwise cryptogenic cirrhosis developed from NAFLD/NASH. Liver biopsy remains a significant feature of studies delineating long-term outcome of NAFLD, some of which have shown that "simple steatosis" is not always non-progressive and benign. Finally, investigators have noted correlations of proposed pathophysiologic processes in NASH with particular histologic features. Therapeutic trials for NASH rely on histologic evaluation as the most sensitive analysis to document effects of treatment. Treatment trials afford an opportunity to evaluate histologic features of resolution, and these trials have also provided an opportunity for correlations of particular histologic lesions with clinical and laboratory features in well-characterized patient populations. These kinds of studies are currently relatively few, but results of a recent study have reinforced the concept of necessary criteria for diagnosis. Current discussions in pathology include identification of lesions of concern for progression, reproducible methods of diagnosis and semiquantification of lesions, and appropriate nomenclature. Matteoni et al. proposed NAFLD types 1-4 based on long-term outcome studies; Brunt et al. proposed a system of grading and staging for NASH that follows methods of separate assessment for necroinflammatory lesions (grade) and fibrosis (stage) accepted in other forms of non-biliary chronic liver disease. Recently, the Pathology Committee of the NIDDK NASH Clinical Research Network has proposed a system of evaluation that encompasses the entire spectrum of NAFLD from steatosis to steatohepatitis with fibrosis for use in upcoming treatment trials. And, just as the clinician cannot distinguish steatosis and steatohepatitis, the pathologist cannot discern if alcohol abuse may be an underlying cause of the lesions. Proposed nomenclature to align with either extant terminology in other forms of chronic liver disease, or to align with our knowledge of underlying cause(s) (such as metabolic syndrome) will be discussed.     

Mitochondrial antiviral signaling protein defect links impaired antiviral response and liver injury in steatohepatitis in mice

Mitochondrial dysfunction is a pathogenic feature of nonalcoholic steatohepatitis (NASH). NASH complicates hepatotropic viral disease. The mitochondrial antiviral signaling protein (MAVS) is the adapter of helicase receptors involved in sensing double-stranded RNA (dsRNA). We hypothesized that impaired MAVS function may contribute to insufficient antiviral response and liver damage in steatohepatitis. We identified reduced MAVS protein levels and increased MAVS association with the proteasome subunit alpha type 7 (PSMA7) in livers from mice given a methionine-choline-deficient (MCD) diet. Decreased association of MAVS with mitochondria and increased cytosolic cytochrome c indicated mitochondrial damage in steatohepatitis. In vivo administration of the synthetic dsRNA polyinosinic:polycytidylic acid [poly(I:C)], but not lipopolysaccharide or cytidine-phosphate-guanosine-rich DNA, resulted in impaired induction of type I interferons (IFNs) and proinflammatory cytokines in steatohepatitis. Consistent with a defect in helicase receptor-induced signaling, there was loss of poly(I:C)-induced translocation of MAVS to the cytosol and decreased IFN regulatory factor 3 phosphorylation. Caspases 1 and 8, both of which cleave MAVS, were increased in MCD diet-fed mice. At baseline, steatohepatitis was associated with increased serum alanine aminotransferase (ALT), apoptosis and caspase 3 activation compared with controls. In contrast to apoptosis in controls, necrosis was induced by poly(I:C) stimulation in steatohepatitis. Hepatocyte necrosis was indicated by elevated serum high-mobility group box protein-1 and ALT and was correlated with increased expression of receptor-interacting protein 3 (RIP3), a master regulator of necrosis. Increased expression of MAVS, PSMA7, and RIP3 messenger RNA was also present in human NASH livers. CONCLUSION: Our novel findings suggest that mitochondrial damage in steatohepatitis extends to MAVS, an adapter of helicase receptors, resulting in inefficient type I IFN and inflammatory cytokine response but increased hepatocyte necrosis and RIP3 induction in response to a dsRNA viral challenge. These mechanisms may contribute to progressive liver damage and impaired viral clearance in NASH.     

Pathology of alcoholic liver disease,can it be differentiated from nonalcoholic steatohepatitis?

The liver involvement in alcoholic liver disease(ALD) classically ranges from alcoholic steatosis, alcoholic hepatitis or steatohepatitis, alcoholic cirrhosis and even hepatocellular carcinoma. The more commonly seen histologic features include macrovesicular steatosis, neutrophilic lobular inflammation, ballooning degeneration, Mallory-Denk bodies, portal and pericellular fibrosis. Nonalcoholic steatohepatitis(NASH) is a condition with similar histology in the absence of a history of alcohol intake. Although the distinction is essentially based on presence or absence of a history of significant alcohol intake, certain histologic features favour one or the other diagnosis. This review aims at describing the histologic spectrum of alcoholic liver disease and at highlighting the histologic differences between ALD and NASH.     

The role of immune mechanisms in alcoholic and nonalcoholic steatohepatitis: a 2015 update

So far, innate immune mechanisms have been recognized as the main responsible for the evolution of both alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH). However, increasing evidence points toward the possible role of adaptive immune responses, as an additional factor in promoting hepatic inflammation in steatohepatitis. In this article, we discuss recent data involving circulating antibodies and lymphocyte-mediated responses in sustaining the progression of ASH and NASH to fibrosis, as well as the possible mechanisms implicated in favoring the onset of adaptive immunity in the setting of steatohepatitis.     

Mechanisms of Fibrosis in Steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a frequent cause of cirrhosis and may lead to liver-related mortality. In Western countries, NASH is the most common liver disease and may progress to advanced fibrosis or cirrhosis in a significant portion of cases. Moreover, NASH, even in the absence of cirrhosis, is associated with the development of hepatocellular carcinoma. An increased risk of cardiovascular events and/or diabetes represents another major problem in these patients. In this review, we discuss recent data on the basic mechanisms leading to the development of fibrosis in nonalcoholic steatohepatitis, in particular those which may identify novel approaches to treatment.     

Does steatohepatitis impair liver regeneration? A study in a dietary model of non-alcoholic steatohepatitis in rats

BACKGROUND: Impaired liver regeneration is a feature of alcoholic hepatitis, but the relative importance of alcohol, nutritional imbalance and inflammatory mediators in causing this effect is unclear. Non-alcoholic steatohepatitis (NASH) is a form of liver disease with similar morphology to alcoholic hepatitis, but the effect of this disorder on liver regeneration is unclear. We, therefore, examined the status of liver regeneration in a rat nutritional model of hepatic steatosis with inflammation, which is morphologically identical to NASH in humans. Methods: Male Wistar rats received a methionine-choline-deficient diet (MCDD) for 4 weeks before experiments and both isocaloric pair-fed and ad libitum-fed rats were used as controls. Following partial hepatectomy (68%), the extent of hepatic regeneration was determined 24 h later using [3H]-thymidine incorporation and restitution of liver mass. Results: There was no significant difference of [3H]-thymidine incorporation in MCDD-fed, pair-fed and ad libitum-fed rats (80+/-27, 78+/-11 and 80+/-6.3 d.p.m./microg DNA, respectively). Similarly, restituted liver masses in three groups of rats were not significantly different (17+/-3.8, 18+/-1.8 and 17+/-3.1% initial liver weight, respectively). Conclusions: The similarities in hepatic histology and cytochrome P450 2E1 induction between this nutritional model of hepatic steatohepatitis and alcoholic steatohepatitis imply that these two disorders share pathogenetic mechanisms. However, liver regeneration is not altered by NASH in rats, indicating that the nutritional and inflammatory changes that appear similar to those of alcoholic liver disease do not cause impairment of liver regeneration.     

Pathogenesis of nonalcoholic steatohepatitis (NASH)

Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of liver diseases that range from hepatic steatosis at the most clinically benign end of the spectrum, through an intermediate lesion, nonalcoholic steatohepatitis (NASH), to cirrhosis at the opposite extreme. Epidemiology studies have estimated that about 20-30% of adults in the United States and other Western countries have NAFLD, and of these about 10% (2-3% of adults) meet the diagnostic criteria of NASH. Studies of animals and humans with obesity-related fatty liver disease have revealed much about the mechanisms that mediate this common pathology. The pathogenesis of NASH is multifactorial and includes insulin resistance, excessive intracellular fatty acids, oxidant stress, mitochondrial dysfunction and the role of innate immunity. This review will briefly discuss the epidemiology of NAFLD and focus on current understanding of the pathogenesis of NASH.     

Angiotensin II type 1 receptor blocker inhibits fibrosis in rat nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is now the most frequent cause of chronic liver impairment in developed countries and is a suggested causative factor in the development of cryptogenic cirrhosis and hepatocellular carcinoma. At present there is no effective and accepted therapy for NASH. The renin-angiotensin system is involved in hepatic fibrosis through activation of hepatic stellate cells, major fibrogenic cells in the liver. Hepatic stellate cells are activated by liver injury to express excessive matrix proteins and profibrogenic cytokines such as transforming growth factor-beta 1. Medicines that inhibit this pathway may be of therapeutic potential in NASH. Using a methionine-choline-deficient rat model of NASH, we studied the potential utility of an angiotensin II type 1 receptor blocker (ARB), olmesartan, on biochemical, histologic, and antioxidant measures of disease activity. ARB significantly attenuated increases in aspartate aminotransferase, activation of hepatic stellate cells, oxidative stress, expression of transforming growth factor-beta 1, expression of collagen genes, and liver fibrosis. CONCLUSION: Our observations strongly suggest a potential preventive role for ARB in the progression of nonalcoholic steatohepatitis.     

Role of liver biopsy in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD), defined as abnormal accumulation (> 5%) of hepatic triglyceride without excess alcohol intake, is the most common form of chronic liver disease in adults and children in the United States. NAFLD encompasses a spectrum of histologic findings including uncomplicated steatosis, steatosis with inflammation and steatohepatitis [nonalcoholic steatohepatitis (NASH)]; the latter can advance to cirrhosis and hepatocellular carcinoma. NASH is currently accepted as the hepatic manifestation of the set of cardiovascular risk factors collectively known as metabolic syndrome. In 1999 a system for histologic grading and staging for NASH was proposed; this was revised by the NASH Clinical Research Network in 2005 for the entire spectrum of lesions in NAFLD, including the lesions and patterns of pediatric NAFLD, and for application in clinical research trials. Diagnosis remains distinct from grade and stage. A recent European proposal separates steatosis from activity to derive a numeric diagnosis of NASH. Even though there have been promising advancements in non-invasive testing, these tests are not yet detailed enough to replace the full range of findings provided by liver biopsy evaluation. Limitations of biopsy are acknowledged, but liver biopsy remains the “gold standard” for diagnosis and determination of amounts of necroinflammatory activity, and location of fibrosis, as well as remodeling of the parenchyma in NASH. This review focuses on the specific histologic lesions of NAFLD and NASH, grading and staging, differential diagnoses to be considered, and the continuing role of the liver biopsy in this important liver disease.     

Obesity and NASH in Japan.

BACKGROUND: NASH is expected to be a major target disease in near future, although we are too short in information to realize NASH. In this study, we revealed the prevalence of fatty liver, which is a background disease of NASH, in Kyoto. Then we made histological diagnosis of NASH from chronic liver disorder with fatty liver. MATERIALS AND METHODS: By using the data obtained from medical check-up with more than 1000 subjects per year in Kyoto, the prevalence of fatty liver on ultrasound, serum ALT, body mass index (BMI) were compared between 1994 and 2004. Next 32 patients with elevated ALT and bright liver on ultrasound were biopsied in order to diagnose them as NASH or not. Biochemical, serological and hormonal parameters as well as adipocytokine profiles were also studied. Lastly, liver tissues from those patients were examined to compare the expression of peroxisome proliferator activator receptor (PPAR) alpha and gamma. RESULTS: It was revealed that the prevalence of fatty liver increased from 12.9 to 34.7% over 10 years. The mean ALT and BMI also increased in this period. From 32 patients, 6 cases were excluded for alcohol, autoimmune hepatitis, and drug-induced liver injury, leaving 26 cases to enter the study. Among them, 12 and 8 patients showed grade 1 and grade 2 steatohepatitis, which were consistant with NASH. Various data were compared among simple steatosis, grade 1 steatohepatitis, and grade 2 steatohepatitis, but highly sensitive CRP was the sole parameter with statistical significance. PPAR alpha seems to be expressed higher in patients with steatohepatitis, although PPAR alpha did not show any significance. CONCLUSION: We found the prevalence of fatty liver was increasing over 10 years. The histological examination showed more patients with grade 1 or grade 2 steatohepatitis than expected, which means we might have much more NASH cases undiagnosed. We were unable to propose reliable diagnostic markers to diagnose NASH from this study.     

Marked elevation of serum mitochondrion-derived markers in mild models of non-alcoholic steatohepatitis in rats

Background and Aim:  In order to find sensitive serum markers in non-alcoholic steatohepatitis, liver-specific injury markers were thoroughly examined in mild models of NASH in rats.
Methods:  Wistar and Sprague–Dawley rats were fed a choline-deficient diet for 4 weeks, and serum activities of liver-specific enzyme markers were examined. In the drug-induced steatohepatitis model, tetracycline (0.4 mmol/kg) was given i.p. to rats and the course of hepatotoxicity was evaluated with serum markers, together with the accumulation of total lipid and thiobarbituric acid-reactive substances in the liver.
Results:  In Wistar rats, serum activities of most enzymes tested were significantly increased. In Sprague–Dawley rats, in contrast, the serum level of ornithine carbamyltransferase and glutamate dehydrogenase were markedly elevated in the choline-deficient diet group compared with the control diet groups, whereas other markers were not significantly increased. In the tetracycline-induced steatohepatitis model, the extent of the increase was much higher in mitochondrial markers and the peak of the increase in these markers corresponded with the increase of hepatic total lipid and thiobarbituric acid-reactive substance.
Conclusions:  These observations show that serum mitochondrial enzyme markers are potent markers for non-alcoholic steatohepatitis in rats and are possibly applicable to humans.