In Vivo Mammillary Body Volume Deficits in Amnesic and Nonamnesic Alcoholics

BACKGROUND: Neuropathological studies use the presence of mammillary body (MB) pathology as a cardinal, diagnostic feature of Wernicke's encephalopathy (WE) in neuropsychiatric diseases, most notably alcoholism. Although Korsakoffs Syndrome (KS), which is marked behaviorally by dense global amnesia, is a typical sequela of WE, it remains controversial whether these two conditions necessarily co-occur and whether MB pathology is therefore a diagnostic requisite for KS. METHODS: We investigated these issues by examining, in vivo, 24 nonamnesic alcoholics (ALC), 5 amnesic alcoholics (KS), and 51 normal controls with three-dimensional MRI and memory testing. MB volume was determined from successive, 1 mm thick slices. RESULTS: The ALC group had significantly smaller MB volumes bilaterally (mean = 54.5 +/- 22.0 mm3) than controls (mean = 66.3 +/- 17.1 mm3), and the KS group had even smaller MB volumes than the ALC group (mean = 20.7 +/- 14.8 mm3). Only 2 ALC patients met historical clinical criteria for past WE, and their MB volumes were well within range of the remaining 22 ALC patients. Although all five KS patients met historical clinical criteria for WE, three KS did not have accompanying dementia and had the same degree of MB volume loss as the ALC; the remaining two KS had accompanying dementia and MB volumes half the volume of the ALC group and of KS patients without dementia. CONCLUSIONS: These findings provide volumetric in vivo evidence that: (1) MB volume deficits do occur in alcoholics without amnesia, although these deficits are not present in ail such alcoholics; (2) greater MB volume deficits are present in alcoholics with clinically detectable amnesia or dementia; (3) MB shrinkage is related to severity of cognitive and memory dysfunction, which suggests a continuum of MB pathology in chronic alcoholism to KS; and (4) the presence of WE in all of the KS patients and in the two ALC patients with the greatest long-term declarative memory deficit supports the possibility of an additional and unique pathology distinguishing nonamnesic and amnesic alcoholism.     

Alcoholic Cerebellar Degeneration Is Not a Dose-Dependent Phenomenon

Eleven alcoholics with cerebellar degeneration (eight with computerized tomography confirmation of cerebellar atrophy) were matched with nonataxic alcoholics and nonalcoholics. There were no laboratory or physiological markers for ataxia, including hemoglobin A1a + b, red blood cell transketolase, liver function enzymes, and measures of reaction time and hand-eye coordination. Acetaldehyde-modified hemoglobin levels (as hemoglobin A1a + b) did not, as previously reported, distinguish between alcoholics and nonalcoholics. There was 24% less annual alcohol consumption in ataxic alcoholics compared with nonataxic alcoholics, 9% less lifetime consumption in ataxic alcoholics, and 33% less maximal daily intake. The finding that ataxic alcoholics do not have higher alcohol consumption than nonataxic alcoholics suggests that alcoholic cerebellar degeneration is not a dose-dependent phenomenon, and that alcoholics with cerebellar degeneration may have an idiosyncratic sensitivity to the neuronal effects of alcohol.     

Brain Atrophy and Cognitive Function in Older Abstinent Alcoholic Men

We used computer-aided magnetic resonance image analysis and an age-normed battery of neuropsychological tests to measure brain atrophy and cognitive function in 14 older abstinent alcoholic men and 11 older controls in the expectation that these subject groups would show the greatest and most persistent cerebral effects consequent to chronic alcoholism. The abstinent alcoholics exhibited cognitive impairments (primarily in memory and visual-spatial-motor skills) compared with the controls. In contrast, we found no difference in global cerebral atrophy between the groups, although two alcoholics had extensive atrophy compared with all other subjects. However, there was a stronger association between age and ventricular dilation in the alcoholic sample compared with controls. We conclude that a substrate other than magnetic resonance imaging-detectable global atrophy must underlie the persistent cognitive impairments evident in the sampled alcoholics. Furthermore, if there are global atrophic changes in the brain associated with chronic alcoholism, these effects are not ubiquitous and/or may be reversible in most patients with sufficient abstinence.     

Mammillary body atrophy in acute liver failure and acute-on-chronic liver failure of nonalcoholic etiology

The most common cause of atrophy of mammillary bodies (MBs) is thiamine deficiency, which is very common in patients with alcoholic liver disease. The purpose of this study was to look for changes in MBs using brain magnetic resonance imaging (MRI) in patients with acute liver failure (ALF), acute-on-chronic liver failure (ACLF) and chronic liver failure (CLF) of non-alcoholic etiology. Volumes of MBs and caudate nuclei (CNs) were quantified in nine patients with ALF, 17 with ACLF, 18 with CLF and in 24 healthy controls. Volume of these structures was quantified again three weeks after clinical recovery in five patients with ALF who had survived their illness. Volume of left, right and both MBs was significantly decreased (p < 0.05) in patients with ALF and ACLF whereas there was no change in patients with CLF, when compared with healthy controls. However CN volumes did not change significantly compared to controls in any of the three patient groups. In the follow-up study significant recovery in volume of MBs was noted compared to baseline values in the ALF patients. We conclude that significant volume loss occurs in MBs in patients with ALF and ACLF of non-alcoholic etiology but not in CLF. This loss of MBs volume recovers substantially in patients with ALF who survive their illness.     

Impaired Delay Eyeblink Conditioning in Amnesic Korsakoff s Patients and Recovered Alcoholics

The performance of amnesic Korsakoff patients in delay eyeblink classical conditioning was compared with that of recovered chronic alcoholic subjects and healthy normal control subjects. Normal control subjects exhibited acquisition of conditioned responses (CRs) to a previously neutral, conditioned tone stimulus (CS) following repeated pairings with an unconditioned air-puff stimulus, and demonstrated extinction of CRs when the CS was subsequently presented alone. Both amnesic Korsakoff patients and recovered chronic alcoholic subjects demonstrated an impairment in their ability to acquire CRs. These results indicate that the preservation of delay eyeblink conditioning in amnesia must depend on the underlying neuropathology of the amnesic syndrome. It is known that patients with amnesia caused by medial temporal lobe pathology have preserved conditioning. We have now demonstrated that patients with anmesia caused by Korsakoff's syndrome, as well as recovered chronic alcoholic subjects, have impaired conditioning. This impairment is most likely caused by cerebellar deterioration resulting from years of alcohol abuse.     

Serum activity of mitochondrial aspartate aminotransferase: a sensitive marker of alcoholism with or without alcoholic hepatitis

Serum activity of the mitochondrial isoenzyme of aspartate aminotransferase (mAST) was measured with an immunological method in 74 subjects. Fourty-six were chronic alcoholics with (30) or without (16) obvious alcoholic liver disease; 28 were nonalcoholic controls among whom 14 had acute or chronic viral hepatitis, the remaining 14 being healthy individuals. Mean mAST activity was much higher in all the alcoholic subjects, with or without liver disease, 10.4 and 1.95 units per liter, respectively, than in the healthy controls (0.43, p less than 0.001). The mean mAST to total AST ratio was similar in the healthy controls and in the patients with viral hepatitis (2.98 and 3.19%, NS), whereas it was about 4 times higher in the alcoholics with a sensitivity which reached 93% in the patients with alcoholic liver disease and 100% in those without. Both gamma-glutamyl transpeptidase and glutamate dehydrogenase serum activities were far less sensitive and specific. As almost all chronic alcoholics had similar abnormal values of mAST/total AST ratio, this leads to question whether "normal" liver may really exist in any of such subjects.     

Further Evidence for a Continuum-of-Impairment Encompassing Male Alcoholic Korsakoff Patients and Chronic Alcoholic Men

A battery of challenging tests was used to assess learning ability and short-term memory in groups of detoxified chronic alcoholics with and without complaints of memory impairment, alcoholic Korsakoff patients, and nonalcoholic controls. While alcoholics without memory complaints did not differ from controls on standardized clinical memory tests, their performance was significantly impaired on our more demanding experimental tests. In contrast, the performance of alcoholics reporting memory complaints was impaired, relative to the other alcoholics, on both clinical and experimental memory tests, overlapping that of the alcoholic Korsakoff patients. These results are consonant with Ryback's continuum-of-impairment hvnothesis.     

CHRONIC ALCOHOLIC PROXIMAL WASTING: PHYSIOLOGICAL, MORPHOLOGICAL AND BIOCHEMICAL STUDIES IN SKELETAL MUSCLE

Abstract Electromyography, muscle histochemistry and assay of all glycolytic enzymes, phosphorylase, glycogen, carnitine and several mitochondrial marker enzymes in skeletal muscle (vastus lateralis) were carried out in two groups. One group comprised chronic alcoholic patients with prominent proximal wasting, the other was an alcoholic group with normal neuromuscular examination. Biochemical results were compared with data from control groups with normal muscle histology and with non-alcohol related type 2b fibre atrophy. Either 2b atrophy factor or 2b variability coefficient were increased in all wasted alcoholic patients, with normal values in alcoholics without wasting. Electromyography studies were usually normal in proximal muscles, although several patients had mild distal neuropathies. A significant fall in activity of phosphorylase and all glycolytic enzymes was found in wasted alcoholics with reference to normal controls. In the non-ethanolic 2b atrophy group the activity of several glycolytic enzymes was also significantly lower, but for each enzyme the mean activity was not depressed to the same extent as in the wasted alcoholic group. Muscle glycogen, carnitine, and mitochondrial marker enzyme activities (isocitrate dehydrogenase, monoamine oxidase, cytochrome oxidase) were normal in alcoholics with proximal wasting. It is concluded that there is no deficiency of mitochondrial marker enzymes in wasted alcoholics and that a significant depression in glycogenolytic and glycolytic enzyme activity is seen which is explained in part, but probably not fully, by 2b fibre atrophy.     

Reduced fronto-cerebellar functional connectivity in chronic alcoholic patients

Background: Alcohol dependence is associated with neurocognitive deficits related to neuropathological changes in structure, metabolism, and function of the brain. Impairments of motor functioning in alcoholics have been attributed to well‐characterized neuropathological brain abnormalities in cerebellum. Methods: Using functional magnetic resonance imaging (fMRI), we studied in vivo the functional connectivity between cerebellar and cortical brain regions. Participants were 10 uncomplicated chronic alcoholic patients studied after 5 to 7 days of abstinence when signs of withdrawal had abated and 10 matched healthy controls. We focused on regions of prefrontal, frontal, temporal, and parietal cortex that exhibited an fMRI response associated with nondominant hand finger tapping in the patients but not in the controls. We predicted that fronto‐cerebellar functional connectivity would be diminished in alcoholics compared with controls. Results: Functional connectivity in a circuit involving premotor areas (Brodmann Area 6) and Lobule VI of the superior cerebellum was reduced in the patients compared with the controls. Functional connectivity was also reduced in a circuit involving prefrontal cortex (Brodmann Area 9) and Lobule VIII of the inferior cerebellum. Reductions in connectivity were specific to fronto‐cerebellar circuits and were not found in other regions examined. Conclusions: Our findings show a pattern in recently abstinent alcoholic patients of specific deficits in functional connectivity and recruitment of additional brain regions for the performance of a simple finger‐tapping task. A small sample, differences in smoking, and a brief abstinence period preclude definitive conclusions, but this pattern of diminished fronto‐cerebellar functional connectivity is highly compatible with the characteristic neuropathological lesions documented in alcoholics and may reflect brain dysfunction associated with alcoholism.     

Thinning of the Corpus Callosum in Older Alcoholic Men: A Magnetic Resonance Imaging Study

A brain image averaging technique was applied to three-dimensional magnetic resonance images to identify visually detectable brain volume abnormalities in chronically alcoholic men, compared with healthy control men. This technique, which was based on pixel-by-pixel statistical probability mapping, revealed a dramatic reduction in the area of the corpus callosum in older alcoholics (age 45 years or older), relative to age-matched controls. Subsequent analysis used anatomical landmarks to outline the borders of midsagittal sections of the corpus callosum in a larger group of alcoholics and controls, who spanned the adult age range from 23 to 71 years. This analysis revealed significant reduction, most prominent in the genu and body, of total callosal area in the alcoholic group relative to the control group; the results were the same whether raw area measures or head size plus age adjusted measure were analyzed. Significant thinning of the callosal body in alcoholics is usually attributed to the relatively rare, nutritional-deficient condition, Marchiafava-Bignami disease. However, callosal thinning was present in vivo in chronic alcoholics without clinical symptoms of severe liver disease, amnesia, or alcoholic dementia. These data suggest that chronic alcoholism can be characterized by a continuum of graded brain dysmorphology, rather than classical alcoholic-related subsyndromes, such as Marchiafava-Bignami disease.     

Serum immunoglobulins (IgG, IgA, IgM) in chronic hepatitis C. A comparison with non-cirrhotic alcoholic liver disease

BACKGROUND/AIMS: Serum immunoglobulin concentrations are commonly elevated in patients with liver cirrhosis. Immunoglobulin class increase may vary depending on the cause of liver disease. Hepatitis C virus is, together with alcohol, a leading cause of chronic liver disease. The present study aimed to evaluate serum IgG, IgA and IgM levels in chronic hepatitis C. Results were compared with those of patients with non-cirrhotic alcoholic liver disease and healthy controls. Special attention was given to cases with minimal liver disease, as an approach to evaluate if the causing agent, independently of liver damage, influences serum immunoglobulin levels. METHODOLOGY: A total of 274 patients with histologically-proven chronic hepatitis C, 121 alcoholics with non-cirrhotic liver disease (steatosis or alcoholic hepatitis), and 75 healthy controls were studied. Serum IgG, IgA, and IgM were assayed by nephelometry. RESULTS: Serum IgG was increased in patients with chronic hepatitis C with respect to both alcoholics (p < 0.001) and healthy controls (p < 0.001). IgG levels were similar in alcoholics and in controls. IgA was increased in patients with non-cirrhotic alcoholic liver disease with respect to both chronic hepatitis C patients (p < 0.001) and controls (p < 0.001). IgA values were similar in subjects with chronic hepatitis C and controls. Selective IgG or IgA alteration was present in cases with minimal liver disease (chronic hepatitis C with a Knodell index equal or lower than 3, and alcoholics with liver steatosis, respectively). CONCLUSIONS: Hepatitis C virus and alcohol are linked to a selective increase of serum IgG and IgA, respectively, even in cases with mild or minimal liver disease.     

Cortical and Subcortical White Matter Damage without Wernicke's Encephalopathy after Recovery from Thiamine Deficiency in the Rat

The relative etiologic roles of ethanol and thiamine deficiency in the cortical atrophy and loss of cerebral white matter in chronic alcoholics are uncertain. The present study examined the distribution of degenerating axons within cortical and subcortical tracts 1 week after recovery from early to late symptomatic stages of thiamine deficiency in the absence of ethanol in Sprague-Dawley rats. The brains of rats exposed to an early symptomatic stage of pyrithiamine-induced thiamine deficiency, 12–13 days of treatment, contained degenerating axons in corpus callosum, anterior commissure, external and internal capsules, optic and olfactory tracts, and fomix and mammillothalamic tracts. A dense pattern of degenerating axons was evident in layers Ill-IV of frontal and parietal cortex. Less intense and more evenly distributed degenerating axons were present in layers IV-VI of frontal, parietal, cingulate, temporal, retrosplenial, occipital, and granular insular cortex. Neuronal counts in mamrnillary body nuclei and areal measurements of the mammillary body were unchanged from controls and the thalamus was relatively undamaged. In animals reversed at later and more advanced symptomatic stages of thiamine deficiency, 14–15 days of treatment, degenerating axons were found in other cortical regions and hippocampus and there was extensive neuronal loss and gliosis within mammillary body and medial thalamus. These results demonstrate that a single episode of thiamine deficiency can selectively damage cortical white matter tracts while sparing the thalamus and mammillary body and may be a critical factor responsible for the pathological and behavioral changes observed in alcoholics without Wernicke's encephalopathy.     

Comparisons of Korsakoff and non-Korsakoff alcoholics on neuropsychological tests of prefrontal brain functioning

BACKGROUND: Evidence suggests that alcoholics exhibit particular deficits in brain systems involving the prefrontal cortex, but few studies have directly compared patients with and without Korsakoff's syndrome on measures of prefrontal integrity. METHODS: Neuropsychological tasks sensitive to dysfunction of frontal brain systems were administered, along with standard tests of memory, intelligence, and visuospatial abilities, to 50 healthy, abstinent, nonamnesic alcoholics, 6 patients with alcohol-induced persisting amnestic disorder (Korsakoff's syndrome), 6 brain-damaged controls with right hemisphere lesions, and 82 healthy nonalcoholic controls. RESULTS: Korsakoff patients were impaired on tests of memory, fluency, cognitive flexibility, and perseveration. Non-Korsakoff alcoholics showed some frontal system deficits as well, but these were mild. Cognitive deficits in non-Korsakoff alcoholics were related to age, duration of abstinence (less than 5 years), duration of abuse (more than 20 years), and amount of alcohol intake. CONCLUSIONS: Abnormalities of frontal system functioning are most apparent in alcoholics with Korsakoff's syndrome. In non-Korsakoff alcoholics, factors contributing to cognitive performance are age, duration of abstinence, duration of alcoholism, and amount of alcohol consumed.     

Temporal discrimination learning in abstinent chronic alcoholics

BACKGROUND: Converging evidence from varied experimental paradigms has demonstrated that the cerebellum is involved in the timing of learned behavior. Given the documented neurological changes secondary to chronic alcoholism, particularly cerebellar degeneration, the ability of recovered chronic alcoholics to learn a temporal discrimination was assessed by using delayed eyeblink classical conditioning. METHODS: Twelve abstinent alcoholic participants and 12 matched control participants were randomly presented 2 clearly discriminable tone conditioned stimuli that were individually paired with 2 different interstimulus intervals. RESULTS: The data revealed a significant alteration in the abstinent alcoholics' peak latency measure at the long interstimulus intervals and an overall impairment in their level of acquisition of conditioned responses. No group differences in extinction were observed. CONCLUSIONS: It was speculated that cerebellar cortical atrophy caused by years of alcohol abuse resulted in the peak latency alteration and that atrophy extending into deep cerebellar nuclei caused the overall impairment in conditioned response acquisition.     

Perceptual learning in detoxified alcoholic men: contributions from explicit memory, executive function, and age

BACKGROUND: Visuospatial and visuoperceptual deficits have consistently been observed in detoxified alcoholics; however, the severity of impairment varies with test and task type. Identifying the component processes and factors that underlie a particular deficit may reveal why some visuospatial and visuoperceptual tasks are more compromised than others and may lead to the specification of neural systems that are particularly vulnerable in alcoholism. METHODS: We examined visuoperception and perceptual learning with a picture fragment identification task in 51 recently detoxified nonamnesic alcoholic men (aged 29-66 years) compared with 63 normal control men (aged 21-70 years). Executive function and explicit declarative memory were also assessed. RESULTS: Despite deficits in the primary components of visuoperception and explicit memory for visuospatial stimuli, the alcoholics showed normal perceptual learning. Although the alcoholics and controls performed at comparable levels on the perceptual learning task, multiple regression analyses indicated that the factors accounting for perceptual learning variance differed between and within groups. Visuoperceptual abilities consistently predicted perceptual learning in the control subjects but not the alcoholic subjects. Explicit memory contributed to perceptual learning performance in both the alcoholic and control groups. Frontal executive ability consistently predicted perceptual learning in the alcoholic subjects, but it had predictive ability only in the control subjects as time elapsed. Age was significantly correlated with perceptual learning performance in both groups. Lifetime alcohol consumption, but not alcoholism duration, was an independent predictor of 1-hr perceptual learning. CONCLUSIONS: These correlational analyses suggest that controls invoke basic visuospatial processes to perform a perceptual learning task, whereas alcoholics invoke higher-order cognitive processes (i.e., frontal executive systems) to perform the same task at normal levels. Use of more demanding cognitive systems by the alcoholics may be less efficient and more costly to processing capacity than those invoked by controls.     

Association of Polymorphism in the Alcohol Dehydrogenase 2 Gene With Alcohol-Induced Testicular Atrophy

Background: Alcohol abuse can induce testicular atrophy, but it only occurs in some alcoholics. Alcohol dehydrogenase (ADH) is located principally on the Leydig cells.
Methods: To investigate whether genetic polymorphism of alcohol dehydrogenase (ADH) 2 and aldehyde dehydrogenase (ALDH) 2 was related to alcoholic testicular atrophy, we determined restriction fragment-length polymorphisms of the ADH2 and ALDH2 genes in 43 Japanese male alcoholics and 50 healthy subjects. An orchidometer was used to determine the testicular size.
Results: Less than 16 ml in testicular size was defined as testicular atrophy. Testicular atrophy was found in 24 (55.8%) cases out of 43 alcoholics. Digestion with MaeIII and Mbo II after polymerase chain reaction amplification showed that the ADH2¹ allele frequency was significantly higher in patients with testicular atrophy than in those without testicular atrophy (χ²= 4.665, p = 0.031), whereas no significant association was observed between testicular atrophy and the ALDH2 gene.
Conclusions: The ADH2¹ allele may be associated with alcoholic testicular atrophy.     

Hepatitis B virus multiplication in the absence of usual serological markers. A study of 146 chronic alcoholics

The possible role of HBV infection in the progression of alcoholic liver disease remains debated. However, serum HBV markers in alcoholics, although present with a high frequency, mainly consist of anti-HBs and/or anti-HBc antibodies. In order to detect an HBV multiplication that could be missed by the usual markers, we looked for HBV-DNA in the serum of 146 chronic alcoholics; the results were compared with those of the usual serological HBV markers. Sixty-eight of the 146 patients could be studied for HBV-DNA both in the liver and the serum. The 146 alcoholics were divided in 48 with normal liver function (group I); 67 with non-cirrhotic alcoholic liver disease (group II); 31 with alcoholic cirrhosis (group III). Among the 146 patients, 17 had a viral multiplication reflected by serum positive HBV-DNA, as against none of 100 healthy controls (P less than 0.01). Six of the 17 had a normal liver function (6/48 = 12.5%), 7 were of group II (7/67 = 10.4%) and 4 had cirrhosis (4/31 = 12.9%). Serum HBV-DNA was associated with HBsAg in 3 occasions; in addition serum HBV-DNA was also present in 5 HBsAg-negative patients with anti-HBc and/or anti-HBs and even in 9 without any usual HBV marker. The overall prevalence of HBV markers in the 146 patients went from 30.8% to 37.0% when serum HBV-DNA was taken into account; it was similar in the 3 groups studied. Eight patients, of the 68 studied, were liver HBV-DNA-positive.(ABSTRACT TRUNCATED AT 250 WORDS)     

Increased Metabolism of Acetaminophen in Chronically Alcoholic Patients

The aim of this work was to determine whether the metabolism of acetaminophen increases in chronic alcoholics, and consequently whether the production of its hepatotoxic metabolite is enhanced. For this purpose, the pharmacokinetics of acetaminophen were compared in 12 alcoholic men and 12 healthy controls. After a 12-hr fast, the patients (on the 3rd hospital day) and volunteers were given 1 g of oral acetaminophen at 8.00 AM. Venous blood samples were drawn before drug intake and at regular intervals after to evaluate plasma acetaminophen concentrations. The elimination half-life of acetaminophen was significantly shorter in the alcoholic patients than in the controls (1.70 ± 0.55 vs. 2.84 ± 0.30 hr, p < 0.001). Similarly, total plasma acetaminophen clearance was significantly higher in the patients than in the controls (29.19 ± 13.37 vs. 24.45 ± 11.10 1/hr, p < 0.05). These results confirm that the metabolism of acetaminophen increases in chronic alcoholism and consequently suggest that its potential liver toxicity might be enhanced.     

Serum proline and blood lactate levels in alcoholic patients without hepatic failure: relationship with alcohol ingestion and histological activity

It has not yet been established whether serum proline and blood lactate levels are increased in alcoholic liver disease. We measured serum proline and blood lactate in controls and in patients with different stages of alcoholic liver disease in the absence of hepatic failure. Samplings were done in both abstinent and drinking alcoholics. Compared to controls, there was a striking increase in serum proline levels in 52 abstinent alcoholics with little or no hepatic fibrosis by histological assessment (0.10 +/- 0.01 vs. 0.155 +/- 0.008; p less than 0.005). Blood lactate levels were within the normal range and did not correlate with serum proline levels. On the other hand, serum proline and blood lactate levels were independent of hepatic necrosis and inflammation scores. In addition, in 10 patients with blood alcohol concentrations between 0.3 mg/ml and 7.8 mg/ml, serum lactate and proline were significantly elevated (2.42 +/- 0.29 mg/ml and 0.275 +/- 0.0026 mg/ml, respectively; p less than 0.005). These results show that there is an association between serum proline levels and the abstinence period in alcoholic patients. They further suggest that in alcoholic patients neither serum proline nor blood lactate concentrations are reliable markers for liver histological activity (necrosis and inflammation) or fibrosis.