Low plasma antibodies specific for phosphatidylethanol in alcohol abusers and patients with alcoholic pancreatitis

Pyruvate and Glutamine Define the Effects of Cholecystokinin and Ethanol on Mitochondrial Oxidation, Necrosis, and Morphology of Rat Pancreatic Acini

OBJECTIVES

The objective of this study was to test whether pyruvate and glutamine affect the ethanol and cholecystokinin (CCK) effects on the mitochondrial function, viability, and morphology of rat pancreatic acini.

METHODS

Respiration was measured with Clark oxygen electrode. Mitochondrial membrane potential, reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H), cell morphology, and viability were studied with fluorescence microscopy.

RESULTS

In vitro, CCK (0.1 nM) caused pyruvate-dependent stimulation of basal and uncoupled respiration, and the effects were abolished by ethanol (20 mM). The combination of ethanol with CCK (2 hours) caused necrosis of approximately 40% acinar cells in medium with glucose, but not with pyruvate and/or glutamine. Cholecystokinin (10 nM) or ethanol with 0.1 nM CCK caused plasma membrane blebbing not related to apoptosis only when both glutamine and pyruvate were present. Glutamine, but not pyruvate, decreased NAD(P)H level and prevented the effects of ethanol with CCK on mitochondrial membrane potential and NAD(P)H, but, in combination with CCK and ethanol, decreased the uncoupled respiration. In vivo, the combination of ethanol (4 g/kg) and CCK (20 pmol/kg) suppressed basal and uncoupled respiration and caused acinar cell blebbing, but not necrosis.

CONCLUSIONS

The lack of sufficient substrate supply in vitro makes pancreatic acinar cells susceptible to necrosis caused by ethanol and CCK in clinically relevant concentrations.

Biomarkers of Alcohol Consumption in Body Fluids - Possibilities and Limitations of Application in Toxicological Analysis

BACKGROUND

Ethyl alcohol is the most popular legal drug, but its excessive consumption causes social problems. Despite many public campaigns against alcohol use, car accidents, instances of aggressive behaviour, sexual assaults and deterioration in labor productivity caused by inebriated people is still commonplace. Fast and easy diagnosis of alcohol consumption is required in order to introduce proper and effective therapy, and is crucial in forensic toxicology analysis. The easiest method to prove alcohol intake is determination of ethanol in body fluids or in breath. However, since ethanol is rapidly metabolized in the human organism, only recent consumption can be detected using this method. Because of that, the determination of alcohol biomarkers was introduced for monitoring alcohol consumption over a wider range of time.

OBJECTIVE

The objective of this study was to review published studies focusing on the sample preparation methods and chromatographic or biochemical techniques for the determination of alcohol biomarkers in whole blood, plasma, serum and urine.

METHODS

An electronic literature search was performed to discuss possibilities and limitations of application of alcohol biomarkers in toxicological analysis.

RESULTS

Authors described the markers of alcohol consumption such as: ethanol, its nonoxidative metabolites (ethyl glucuronide, ethyl sulfate, phosphatidylethanol, ethyl phosphate, fatty acid ethyl esters) and oxidative metabolites (acetaldehyde and acetaldehyde adducts). We also discussed issues concerning the detection window of these biomarkers, and possibilities and limitations of their use in routine analytical toxicology for monitoring alcohol consumption or sobriety during alcohol therapy.

An automated sample preparation approach for routine liquid chromatography tandem-mass spectrometry measurement of the alcohol biomarkers phosphatidylethanol 16:0/18:1, 16:0/16:0 and 18:1/18:1

BACKGROUND

Phosphatidylethanols (PEths) are currently under investigation as highly sensitive and specific direct biomarkers of long-term alcohol abuse. PEths belong to a group of aberrant phospholipids formed in erythrocyte membranes in presence of ethanol by the catalytic action of the enzyme phospholipase D on phosphatidylcholine. Compared to other alcohol biomarkers, a higher sensitivity (94.5-100%) and specificity (100%) characterizes PEth species.

METHOD

Prior to detection, an important practical aspect in the work-flow of PEths analysis is the sample preparation step. To date, traditional techniques such as liquid-liquid extraction (LLE) and solid phase extraction (SPE) require multiple steps to remove blood interferences. Due to the simplicity of use and the possibility of automation, sample filtration is also a widespread technique in biomedical laboratories. In this work, a reliable sample preparation method based on an automated filtration with Phree™ Phospholipid Removal Plates (Phenomenex, California, USA) was developed to extract PEths from human whole blood. Surface characteristics of Phospholipids Removal material allow phospholipids retention on the filter and a suitable PEths recovery after elution. The blood samples were added with internal standard (IS) and purified in acetonitrile (1 mL). After centrifugation, supernatants were applied to the Phospholipids Removal Plates in an automated workstation. After washing, the phospholipids retained on the filter were eluted with 1-mL 2-propanol 1% ammonia. PEth 16:0/18:1, PEth 16:0/16:0 and PEth 18:1/18:1 were extracted using the proposed method and detected by LC-MS/MS operated in electron spray ionization (ESI). The detection of all compounds was based on multiple reaction monitoring (MRM) transitions. This method was validated for the quantitative profiling of PEth molecular species in human blood collected from heavy and social drinkers.

RESULTS

The method was validated according to Food and Drug Administration (FDA) guidelines. Linearity was observed in the 25-1250 (PEth 16:0/18:1) and 5-250 (PEth 16:0/16:0 and PEth 18:1/18:1) ng/mL range with a correlation coefficient (r²) between 0.997 and 0.999 for all three compounds. Moreover, the nominal concentrations of non-zero calibrators were ±15%. Variation coefficient (%CV) was < 10% for all the analytes, while lowest limit of quantitation (LLOQ) was found to be 1.25 ng/mL for PEth 16:0/18:1, 0.50 ng/mL for PEth 16:0/16:0 and 0.50 ng/mL for PEth 18:1/18:1. Intra- and inter-day precision and accuracy were always lower than 14% and 11%, respectively. Analytical recovery was higher than 68.8% for all analytes. Sample stability at 4 °C and -20 °C showed a concentration drop lower than 20% up to 4 weeks. Extracts were stable for 7 days in the autosampler and 30 days at -20 °C and 4 °C in a closed vial. The procedure was successfully applied to blood samples collected from heavy drinkers (n = 8), social drinkers (n = 5), and teetotalers (n = 7).

CONCLUSIONS

Due to the simplicity of application and the possibility of automation, sample filtration is well suited for a clinical and forensic laboratory. To monitor alcohol consumption, an analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) with novel and automated sample preparation was developed and validated for the simultaneous quantification of PEth 16:0/18:1, PEth 16:0/16:0 and PEth 18:1/18:1 in whole blood samples, characterized by a fast sample preparation and lower pre-analysis costs than other extraction procedures.

Sex-specific association between serum immunoglobulin-M and brachial ankle pulse wave velocity in a Chinese population: Danyang Study

Emerging evidence supports a causal role for the immunoglobulin-M (IgM) as a protector of atherosclerosis. Since arterial stiffness is an index of subclinical atherosclerosis, we propose that IgM may play an important role in arterial stiffness. As the level of IgM differs between sexes, we investigate the sex-specific association of serum IgM with arterial stiffness in a Chinese population. The study subjects were recruited from Danyang in 2017. Using the Omron VP-1000 system, we measured brachial ankle pulse wave velocity (baPWV). Serum IgM concentration was measured by the immunoturbidimetry method. The 1030 study participants (mean age = 54.3 ± 9.0 years) included 407 men (39.5%), 428 hypertensive (41.6%), 80 diabetic (7.8%), and 512 arterial stiffness patients (49.7%). Serum IgM concentration was lower in men than women (0.97 vs. 1.26 μg/mL, P < 0.001) and negatively with alcohol intake (r = -0.11 in men and r = -0.07 in women, P ≤ 0.09). In multiple regression analyses, serum IgM concentration was negatively associated with baPWV in women (-0.82 m/s per 10-time increase in serum IgM concentration, P = 0.009) but not in men. In multivariable logistic regression analyses, elevated serum IgM concentration was associated with lower risks for arterial stiffness in women (OR = 0.26; 95% CI 0.08-0.82; P = 0.02) but not in men (OR = 0.66; 95% CI 0.17-2.62; P = 0.55). Categorical analyses produced similar results. Serum IgM is negatively associated with baPWV and accordingly associated with a lower risk of arterial stiffness in women.

Pilot investigation of a phosphatidylethanol-based contingency management intervention targeting alcohol use

Phosphatidylethanol (PEth) can be detected in blood from 14 to as many as 28 days after alcohol consumption, depending on the amount and frequency of alcohol consumed. PEth may have utility for verifying abstinence in a contingency management (CM) intervention for alcohol use, particularly in settings where frequent verification of abstinence is impossible or impractical. Five nontreatment-seeking heavy drinkers (40% men) participated in an 11-week, ABA-phased within-subject experiment for which they submitted blood spots for PEth measurement, urine samples for ethyl glucuronide (EtG) testing, and self-report drinking data weekly. Participants received reinforcers for submitting samples throughout the A phases. During the B phase (CM phase), they received additional reinforcers when their PEth level was reduced from the previous week and was verified by a negative EtG (<150 ng/ml) urine test and self-report. PEth, EtG, and self-report outcomes were compared between A phases (Weeks 1-3, 8-11) and B phases (Weeks 4-7). During the A phases, 23% of PEth results indicated alcohol abstinence, whereas 53% of PEth samples submitted during the CM (B phase) indicated alcohol abstinence. Participants were more likely to submit EtG-negative urine samples and report lower levels of drinking and heavy drinking during the B phase, relative to the A phases. We also explored the ability of PEth to detect self-reported drinking. The combined PEth homologs (16:0/18:1 and 16:0/18:2) predicted self-reported drinking with area under the curve from 0.81 (1 week) to 0.80 (3 weeks). Results support the initial feasibility of a Peth-based CM intervention. (PsycINFO Database Record

Carbamyl adducts on low-density lipoprotein induce IgG response in LDLR-/- mice and bind plasma autoantibodies in humans under enhanced carbamylation

AIMS

Post-translational modification of proteins via carbamylation predicts increased risk for coronary artery disease. Uremia and smoke exposure are known to increase carbamylation. The aim was to investigate the role of carbamylated low-density lipoprotein (LDL) immunization on antibody formation and atherogenesis in LDL receptor-deficient (LDLR-/-) mice, and to study autoantibodies to carbamylated proteins in humans with carbamylative load.

RESULTS

LDLR-/- mice immunized with carbamylated mouse LDL (msLDL; n=10) without adjuvant showed specific immunoglobulin G (IgG) antibody levels to carbamyl-LDL and malondialdehyde-modified LDL (MDA-LDL) but not to oxidized LDL or native LDL. Immunization did not influence the atherosclerotic plaque area compared with control LDLR-/- mice immunized with native msLDL (n=10) or phosphate-buffered saline (n=11). Humans with high plasma urea levels, as well as smokers, had increased IgG autoantibody levels to carbamyl-modified proteins compared to the subjects with normal plasma urea levels, or to nonsmokers.

INNOVATION

Carbamyl-LDL induced specific IgG antibody response cross-reactive with MDA-LDL in mice. IgG antibodies to carbamyl-LDL were also found in human plasma and related to conditions known to have increased carbamylation, such as uremia and smoking. Plasma antibodies to carbamylated proteins may serve as new indicator of in vivo carbamylation.

CONCLUSION

These data give insight into mechanisms of in vivo humoral recognition of post-translationally modified structures. Humoral IgG immune response to carbamylated proteins is suggested to play a role in conditions leading to enhanced carbamylation, such as uremia and smoking.

Enhanced polyamine catabolism disturbs hematopoietic lineage commitment and leads to a myeloproliferative disease in mice overexpressing spermidine/spermine N¹-acetyltransferase

Spermidine/spermine N(1)-acetyltransferase (SSAT) regulates intracellular polyamine levels by catabolizing spermidine and spermine which are essential for cell proliferation and differentiation. Hematological characterization of SSAT overexpressing mice (SSAT mice) revealed enhanced myelopoiesis and thrombocytopoiesis leading to increased amounts of myeloid cells in bone marrow, peripheral blood, and spleen compared to wild-type animals. The level of SSAT activity in the bone marrow cells was associated with the bone marrow cellularity and spleen weight which both were significantly increased in SSAT mice. The result of bone marrow transplantations indicated that both the intrinsic SSAT overexpression of bone marrow cells and bone marrow microenvironment had an impact on the observed hematopoietic phenotype. The Lineage-negative Sca-1(+) c-Kit(+) hematopoietic stem cell (HSC) compartment in SSAT mice, showed enhanced proliferation, increased proportion of long-term HSCs and affected expression of transcription factors associated with lineage priming and myeloid differentiation. The proportions of common myeloid and megakaryocytic/erythroid progenitors were decreased and the proportion of granulocyte-macrophage progenitors was increased in SSAT bone marrow. The data suggest that SSAT overexpression and the concomitantly accelerated polyamine metabolism in hematopoietic cells and bone marrow microenvironment affect lineage commitment and lead to the development of a mouse myeloproliferative disease in SSAT mice.

Phosphatidylethanol in blood as a marker of chronic alcohol use: a systematic review and meta-analysis

The present paper aims at a systematic review of the current knowledge on phosphatidylethanol (PEth) in blood as a direct marker of chronic alcohol use and abuse. In March 2012, the search through “MeSH” and “free-text” protocols in the databases Medline/PubMed, SCOPUS, Web of Science, and Ovid/Embase, combining the terms phosphatidylethanol and alcohol, provided 444 records, 58 of which fulfilled the inclusion criteria and were used to summarize the current evidence on the formation, distribution and degradation of PEth in human blood: (1), the presence and distribution of different PEth molecular species (2), the most diffused analytical methods devoted to PEth identification and quantization (3), the clinical efficiency of total PEth quantification as a marker of chronic excessive drinking (4), and the potential utility of this marker for identifying binge drinking behaviors (5). Twelve papers were included in the meta-analysis and the mean (M) and 95% confidence interval (CI) of total PEth concentrations in social drinkers (DAI ≤ 60 g/die; M = 0.288 μM; CI 0.208–0.367 μM) and heavy drinkers (DAI > 60 g/die; M = 3.897 μM; CI 2.404–5.391 μM) were calculated. The present analysis demonstrates a good clinical efficiency of PEth for detecting chronic heavy drinking.

Phosphatidylethanol (PEth) as a biomarker of alcohol consumption in HIV-positive patients in sub-Saharan Africa

BACKGROUND

Alcohol is heavily consumed in sub-Saharan Africa and affects HIV transmission and treatment and is difficult to measure. Our goal was to examine the test characteristics of a direct metabolite of alcohol consumption, phosphatidylethanol (PEth).

METHODS

Persons infected with HIV were recruited from a large HIV clinic in southwestern Uganda. We conducted surveys and breath alcohol concentration (BRAC) testing at 21 daily home or drinking establishment visits, and blood was collected on day 21 (n = 77). PEth in whole blood was compared with prior 7-, 14-, and 21-day alcohol consumption.

RESULTS

(i) The receiver operator characteristic area under the curve (ROC-AUC) was highest for PEth versus any consumption over the prior 21 days (0.92; 95% confidence interval [CI]: 0.86 to 0.97). The sensitivity for any detectable PEth was 88.0% (95% CI: 76.0 to 95.6) and the specificity was 88.5% (95% CI: 69.8 to 97.6). (ii) The ROC-AUC of PEth versus any 21-day alcohol consumption did not vary with age, body mass index, CD4 cell count, hepatitis B virus infection, and antiretroviral therapy status, but was higher for men compared with women (p = 0.03). (iii) PEth measurements were correlated with several measures of alcohol consumption, including number of drinking days in the prior 21 days (Spearman r = 0.74, p < 0.001) and BRAC (r = 0.75, p < 0.001).

CONCLUSIONS

The data add support to the body of evidence for PEth as a useful marker of alcohol consumption with high ROC-AUC, sensitivity, and specificity. Future studies should further address the period and level of alcohol consumption for which PEth is detectable.