Enzymes and circulating proteins as markers of alcohol abuse

What the lab can and cannot do: clinical interpretation of drug testing results

Urine drug testing is one of the objective tools available to assess adherence. To monitor adherence, quantitative urinary results can assist in differentiating "new" drug use from "previous" (historical) drug use. "Spikes" in urinary concentration can assist in identifying patterns of drug use. Coupled chromatographic-mass spectrometric methods are capable of identifying very small amounts of analyte and can make clinical interpretation rather challenging, specifically for drugs that have a longer half-life. Polypharmacy is common in treatment and rehabilitation programs because of co-morbidities. Medications prescribed for comorbidities can cause drug-drug interaction and phenoconversion of genotypic extensive metabolizers into phenotypic poor metabolizers of the treatment drug. This can have significant impact on both pharmacokinetic (PK) and pharmacodynamic properties of the treatment drug. Therapeutic drug monitoring (TDM) coupled with PKs can assist in interpreting the effects of phenoconversion. TDM-PKs reflects the cumulative effects of pathophysiological changes in the patient as well as drug-drug interactions and should be considered for treatment medications/drugs used to manage pain and treat substance abuse. Since only a few enzyme immunoassays for TDM are available, this is a unique opportunity for clinical laboratory scientists to develop TDM-PK protocols that can have a significant impact on patient care and personalized medicine. Interpretation of drug screening results should be done with caution while considering pharmacological properties and the presence or absence of the parent drug and its metabolites. The objective of this manuscript is to review and address the variables that influence interpretation of different drugs analyzed from a rehabilitation and treatment programs perspective.

Transcriptome analysis of garlic-induced hepatoprotection against alcoholic fatty liver

Fatty liver induced by alcohol abuse is a major worldwide health hazard leading to morbidity and mortality. Previous studies indicate antifatty liver properties of garlic. This study investigated the molecular mechanisms of garlic oil (GO) or diallyl disulfide (DADS) imparted hepatoprotection against alcohol induced fatty liver in C57BL/6 mice using microarray-based global gene expression analysis. Alcohol liquid diet resulted in severe fatty liver with increased levels of serum aspartate aminotransferease and alanine aminotransferease as well as triglycerides and decreased levels of liver glutathione and antioxidant enzymes. The major canonical pathways implicated by alcohol treatment are the metabolisms of xenobiotics by cytochrome P450, glutathione, and arachidonic acid. Treatment with DADS or GO normalized the serum aminotransferease levels and liver antioxidant enzymes and reduced the contents of triglycerides and cholesterol. The canonical pathways involved in the amelioration of liver include arachidonic acid metabolism, altered T cell and B cell signaling, tryptophan metabolism, antigen presentation pathway for DADS, metabolism of xenobiotics, mitotic roles of Polo-like kinase, fatty acid metabolism, LPS/IL-1 mediated inhibition of RXR function, and C21-steroid hormone metabolism for GO.

Serum alcohol dehydrogenase levels in patients with mental disorders

Alcohol dehydrogenase (ADH) was assessed in 81 patients admitted to hospital for treatment for alcohol dependence with or without liver cirrhosis, 20 patients with bipolar disorder treated with lithium carbonate and 41 patients with various mental disorders treated with psychopharmacologic agents. Testing the hypothesis of the arithmetic mean showed that in alcohol dependents the arithmetic mean of ADH activity (12.19 nkat/l+/-5.61) differs significantly from that in healthy subjects (4.45 nkat/l+/-2.31) and in the group with ethanol poisoning (6.24 nkat/l+/-3.65) there is none. In the group with bipolar disorder, treated with lithium (7.39 nkat/l+/-3.11) and, in the group of patients treated with psychiatric drugs because of various mental disorders (7.79 nkat/l+/-8.51), the differences are statistically significant. In our opinion, assessing ADH activity in the sera of alcohol dependents could be an additional marker advantageous to the diagnostics, course and monitoring of therapy in such patients. In the groups of patients with mental disorders treated with psychotropic drugs, the increased ADH activity was found to be a more sensitive marker for the detection of drug hepatotoxicity.

The analysis of carbohydrate-deficient transferrin, marker of chronic alcoholism, using capillary electrophoresis

Carbohydrate-deficient transferrin (CDT) is currently considered to be the best available marker for the diagnosis of chronic alcoholism. A large variety of methods have been developed, demonstrating the need for standardisation. Commercially available anion-exchange chromatographic-based assays are easy to use and require no specialised, expensive instruments. However, these methods cannot identify genetic transferrin variants or the carbohydrate-deficient glycoprotein syndrome. In 1989, a capillary isoelectric focusing method was developed for quantitative measurement of CDT. Despite the optimal resolution, this method is not easily applied in a clinical routine environment due to the complexity of analysis. Capillary electrophoresis in a polymer network using coated capillaries allowed full resolution of the sialoforms of human transferrin. The drawbacks due to an expensive and time-consuming sample preparation were eliminated when a method in neat serum was developed. Capillary zone electrophoresis allowed full resolution of the transferrin isoforms with a high analytical performance in a short analysis time thanks to a strong electroosmotic flow. Genetic transferrin variants were easily detected, avoiding false-positive results. Also, using capillary zone electrophoresis, it was shown that CDT is a suitable marker of chronic alcohol abuse detection in transferrin CD (common/cathodal) variants.

Biomarkers as aids to identification of relapse in alcoholic patients

Since return to drinking is common in patients recovering from alcoholism, recognition of relapse should be an important component of treatment. Recurrent assessment with biochemical measures can provide clinicians with useful information on the drinking status of their patients. This chapter addresses issues surrounding the importance of early detection of relapse, describes biochemical markers that may assist in this, reviews relevant scientific investigations, and offers recommendations to researchers and clinicians.

Biochemical markers of alcohol use in pregnant women

OBJECTIVES

To describe the serious health consequences of alcohol (ethanol) use, especially as they relate to pregnancy and the development of fetal alcohol syndrome (FAS) and fetal alcohol effects (FAE). The classic markers of alcohol exposure, including blood/breath alcohol, gamma-glutamyl transferase (gammaGT), mean corpuscular volume (MCV), hemoglobin-associated acetaldehyde (HAA) and carbohydrate deficient transferrin (CDT), are valuable and their methods of analysis are reviewed.

CONCLUSIONS

Since both FAS and FAE represent two of the leading preventable causes of mental retardation and birth defects, identification of alcohol use early in pregnancy is important to avoid adverse fetal outcomes. Unfortunately, the diagnosis of FAS and FAE is usually made after birth, when alcohol damage has become irreversible and permanent. The clinical laboratory can help prevent this damage and make a valuable contribution in assessing prenatal alcohol use. The clinical utility of blood/breath alcohol, gammaGT, MCV, HAA and CDT in alcohol use identification, especially in pregnancy, is substantial. Although none of the markers singularly has adequate sensitivity and specificity for screening, their diagnostic utility increases when measured as a panel. This is especially true in detecting alcohol use in pregnancy where the presence of several positive markers was correlated with the presence of alcohol-related fetal effects.

Human fetuin/alpha2HS-glycoprotein level as a novel indicator of liver cell function and short-term mortality in patients with liver cirrhosis and liver cancer

OBJECTIVE

Human fetuin/alpha2HS-glycoprotein (AHSG) is synthesized by hepatocytes. We intended to determine whether liver dysfunction or acute phase reaction is dominant in the regulation of its serum concentrations and to see if decreased AHGS levels are associated with short-term mortality.

DESIGN

We determined the serum AHSG levels in patients with acute alcoholic, acute A, B, and Epstein-Barr virus hepatitis, alcoholic cirrhosis, and hepatocellular cancer and correlated them to conventional laboratory parameters of inflammation and liver function. Patients were followed for 1 month.

METHODS

Serum AHSG was determined by radial immunodiffusion.

RESULTS

Compared to controls, significantly lower AHSG levels were found in patients with liver cirrhosis and hepatocellular cancer but not the acute viral hepatitides. Strong positive correlation with serum transferrin, albumin and prothrombin was found. Febrile episodes were not associated with significantly decreased AHSG levels. Concentrations below 300 microg/ml were associated with high mortality rate (52.0%; relative risk, 5.497; 95% confidence interval, 2.472-12.23; P < 0.0001). Of all laboratory parameters studied serum AHSG levels showed the greatest difference between deceased and survived patients with cirrhosis and cancer. Moreover, other acute phase reactants did not differ significantly. The multiple logistic regression analysis indicated that the decrease of serum AHSG is independent of all other variables that were found decreased in deceased patients.

CONCLUSIONS

Decreased serum AHSG concentration is due rather to hepatocellular dysfunction than the acute phase reaction and is an outstanding predictor of short-term mortality in patients with liver cirrhosis and liver cancer.

Evaluation of the application of carbohydrate deficient transferin in a general hospital; recommendations for use

We performed a retrospective evaluation of the use of carbohydrate deficient transferrin (CDT) in a general hospital, for diagnosing alcohol abuse. The high specificity for the CDT test and lower sensitivity as reported in the literature were confirmed. Alcohol anamnesis proved rather often to be incomplete. In intensive care medicine, the CDT investigation could be used as a guide to diagnoses and treatment, especially for patients that are difficult to communicate with. For being of use here, results of the CDT determination should be available within a day. CDT proved to be of use also in psychiatric medicine, the test being of help in clarifying the patients acohol addiction.

Joint influence of alcohol, tobacco, and coffee on biological markers of heavy drinking in alcoholics

BACKGROUND

Recent reports suggest that gamma-glutamyl transferase (GGT) decreases with coffee intake. The aim of this study was to examine the joint influence of alcohol, tobacco, cotinine, coffee, and caffeine on biological markers of heavy drinking in an alcoholic population.

METHODS

Subjects were 160 alcohol-dependent inpatients. Biological assessments, performed at admission, were plasma levels of GGT, apolipoprotein AI, aspartate aminotransferase, and mean corpuscular volume (MCV), and urine cotinine and caffeine indexes. Years of alcohol abuse and of smoking, alcohol and coffee intake, and smoking rate were estimated in a semistructured interview, and Fagerström Tolerance Questionnaire was completed by inpatients.

RESULTS

Coffee intake, but not caffeine, correlated negatively with biological markers of heavy drinking, after controlling for alcohol and tobacco intake. Years of smoking correlated positively to MCV, after controlling for alcohol and coffee intake.

CONCLUSIONS

Concerning the effect of coffee, the most likely hypothesis is that noncaffeine coffee fractions have a protective effect on liver cells. Concerning the effect of smoking, one can propose that the increase of MCV with smoking could be a consequence of carbon monoxide inhalation, leading to hypoxemia, or of folate deficiency.

Reported alcohol consumption and the serum carbohydrate-deficient transferrin test in third-year medical students

The serum carbohydrate-deficient transferrin (CDT) test was performed on 143 third-year medical students along with questionnaires for the self-reporting of alcohol consumption during the last 2 weeks, the last 6 months, and questions on any alcohol-related untoward events. We found that the CDT test has poor sensitivity for detecting binge drinking in our population of students, despite some likely under-reporting of drinking. Self-reporting of drinking is commonly unreliable, and we found no significant correlation between the CDT concentrations in serum and the magnitude of self-reported alcohol use during 2-week and 6-month periods. Hangover was by far the commonest self-reported untoward event, and there was a highly significant relationship (P < 0.001) between drinking and untoward events. From a small population of non-drinkers, we estimated the reference ranges for CDT to be <27 U/l for men and <35 U/l for women.

Usefulness of carbohydrate-deficient transferrin in alcoholic patients with normal gamma-glutamyltranspeptidase

The biological diagnosis of alcoholism is conducted routinely by assay of gamma-glutamyltranspeptidase (GGT) and mean corpuscular volume (MCV). However, their low specificity and sensitivity have prompted research to find other more reliable parameters. Stibler showed an increase in desialylated transferrin [carbohydrate-deficient transferrin (CDT)] in alcoholic patients. The normal value of the serum CDT concentration is under 60 mg/liter; a value between 60 and 100 mg/liter indicates probable alcoholism, and a value > 100 mg/liter indicates a very high probability of alcoholism (specificity: 99%). Its sensitivity ranges from 60 to 91%, and its specificity ranges from 92 to 100%. Its half-life is 17 +/- 4 days. CDT is thus a useful laboratory marker, but its assay is costlier and more complex than that of GGT. This study concerns 31 alcohol-dependent patients as defined by DSM-IV, with GGT levels in the normal range. It evaluates CDT at day 0 and its time course after 15 days withdrawal. GGT and MCV were assayed concomitantly. Remarkably, the results show a sensitivity of 83.9 (26 positives of 31) in this particular population and a specificity of 92.2. The fall in CDT after 15 days withdrawal was 36%. CDT is thus a particularly useful marker for the diagnosis and follow-up of alcoholics with normal GGT levels.

Increased serum concentrations of carbohydrate-deficient transferrin (CDT) in patients with cystic fibrosis

Carbohydrate-deficient transferrin (CDT) has been reported to be one of the best laboratory markers in serum (S) for detection of alcohol abuse. We have studied S-CDT values in cystic fibrosis (CF) patients and show that CF patients have increased S-CDT values without high alcohol consumption. CF patients have abnormalities in their protein glycosylation and sialylation, which may explain the increased S-CDT values.

Genetic markers of alcohol abuse

In this paper, we review the current status of genetic markers for the development of alcohol abuse. Family, twin, half-sibling and adoption studies of alcoholic subjects suggest that the heritability of liability to alcoholism is at least 50%. These findings have fuelled intensive investigation in the fields of neurology, biochemistry, genetics and molecular biology aimed at the identification of markers for the risk of alcoholism. The most promising of these are discussed in detail. Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) polymorphisms, specifically the ADH3*1, ADH2*2, and ALDH2*2 genotypes appear to confer a protective effect against alcoholism, most notably in Oriental subjects. Caucasian alcohol abusers and their first-degree relatives exhibit depressed platelet monoamine oxidase activity, the degree of which is greater in Type II than Type I alcoholics. Electrophysiological characteristics of alcoholics and those at risk for developing alcoholism have also been identified, including the reduced amplitude of the event-related brain potential and, after ethanol ingestion, characteristic EEG alpha-wave activity. Lower platelet adenylate cyclase activity is seen in alcoholics compared to controls, presumably as a result of over-expression of an inhibitory G-protein. Markers related to other signal transduction pathways of the central nervous system including the serotoninergic, muscarinic and dopaminergic systems are also discussed. In this group of markers, the putative association between the inheritance of the AI allele of the D2 dopamine receptor and the susceptibility to alcoholism provides the most dramatic illustration of the challenges presently existing in this field of scientific investigation. Current limitations in the definition, diagnosis and classification of alcoholism, the confounding influences of race and gender on association studies, as well as the statistical approach of linkage studies are discussed as they relate to the endeavor to uncover valid genetic markers for the risk of alcoholism.