Assays for Acetaldehyde-Derived Adducts in Blood Proteins Based on Antibodies Against Acetaldehyde/Lipoprotein Condensates

Oxidative stress and biochemical indicators in blood of patients addicted to alcohol treated for acute ethylene glycol poisoning

Ethylene glycol (EG), in addition to its neurotoxic and nephrotoxic effects, evokes oxidative stress. The aim of this study was to assess the influence of the ethylene glycol on the biochemical indicators and oxidoreductive balance of patients treated for acute poisoning. The total study group consisted of 56 persons including 26 alcoholics who took EG as a substitute for ethyl alcohol in the course of alcohol dependence syndrome and 30 controls. Severity of poisoning, results of acid-base parameters, biochemical, and toxicological tests as well as biomarkers of the oxidative stress in blood were analyzed during the patients' hospitalization. The key issue was to assess the oxidative stress and biochemical disturbances caused by EG and the type of treatment applied in the course of poisoning. Significant changes in some parameters were found both at time of diagnosis and after treatment initiation (ethanol as an antidote and hemodialysis). The most important differences included the activity of hepatic parameters (aspartate aminotransferase, AST) and oxidative stress markers like catalase (CAT); correlation of the lipid peroxidation products level (TBARS) with urea concentration has been shown. On the last day of the hospitalization, in some cases, the mutual correlation between the evaluated markers were observed, for example, between alanine transaminase (ALT) and glutathione reductase (GR), and urea concentration and glutathione level (GSH/GSSG). The concentration of ions (H⁺) had a major impact on the oxidoreductive balance, correlating with the elevated GR and GSH/GSSG levels.

ERYTHROCYTE THIAMINE (Th) ESTERS: A MAJOR FACTOR OF THE ALCOHOL WITHDRAWAL SYNDROME OR A CANDIDATE MARKER FOR ALCOHOLISM ITSELF?

AIMS

Thiamine (Th) deficiency is a major problem in alcoholics. In this study, the relationship of alcohol withdrawal syndrome (AWS) to Th and its esters, as well as the diagnostic power of Th and its esters were investigated.

PATIENTS AND METHODS

Th and its esters were assessed in a series of chronic alcoholics (and in controls) using an improved method.

RESULTS

No association was found between AWS severity and Th and its esters, while the diagnostic power of thiamine diphosphate (TDP) and Th was very high. TDP was the most significant among the parameters under study, confirming that erythrocyte TDP is a suitable marker of alcoholism: TDP sensitivity across subjects was 84.1%, specificity 85.4%, positive predictive value 82.4%, and negative predictive value 88.0%.

Alcoholic macrocytosis--is there a role for acetaldehyde and adducts?

Although alcohol abuse is known to cause a wide array of adverse effects on blood cell formation, the molecular mechanisms by which alcohol exerts its toxic actions have remained poorly defined. Elevated mean corpuscular volume (MCV), macrocytosis, is the most typical morphological abnormality induced by excessive ethanol consumption. This paper reviews recent data indicating that acetaldehyde, the first metabolite of ethanol, may play a role in the haematological derangements in peripheral blood cells and in bone marrow of alcoholic patients. Studies in experimental animals and in human alcoholics have shown that acetaldehyde can bind to proteins and cellular constituents forming stable adducts. Elevated adduct levels have been found from the erythrocytes of alcohol abusers, which may also be associated with ethanol-induced effects in haematopoiesis and adverse consequences in cellular functions.

T cell proliferative responses to malondialdehyde-acetaldehyde haptenated protein are scavenger receptor mediated

Malondialdehyde-acetaldehyde (MAA) haptenated proteins have been described in disease processes related to prolonged oxidative stress (via malondialdehyde production), such as alcohol liver disease (ALD), non-alcoholic non-steatohepatitis (NASH) and atherosclerosis. Experimentally, high titer IgG1 antibody responses are seen after immunization without adjuvant; however, T cell proliferative responses and the role of scavenger receptors in this immunogenicity has not previously been described. In this study, T cell proliferative responses to the carrier protein, but not the MAA hapten itself, were identified in vitro. Moreover, these T proliferative responses were inhibited when MAA-hen egg lysozyme (HEL) was co-immunized with excess scavenger receptor ligand polyG (poly-guanylic acid), implicating the role of (a) scavenger receptor(s) in initiating the T helper cell response. Activated B cells were unable to process and present MAA-HEL preferentially to T cells, while thioglycollate-elicited (but not Con A-elicited) macrophages and dendritic cells (DC) did so with approximately 32-fold less MAA-HEL than native antigen necessary to initiate equal proliferative responses. While this preferential processing and presentation may be related to several factors, preferential binding of MAA haptenated proteins mediated by scavenger receptors may be one mechanism. IL-4 was absent from the supernatants of T proliferative assays despite a strong IgG1 response in vivo, although the TH2 cytokines IL-6 and IL-10 were expressed. Since the modification of proteins by the MAA have previously been shown to occur after ethanol consumption in vivo, the ability of MAA haptens to experimentally enhance immune responses, specifically humoral and T cell responses, may represent mechanisms by which autoimmune phenomena found in ALD occur.