Francisco-Javier Laso

Association of µ‐opioid receptor (OPRM1) gene polymorphism with response to naltrexone in alcohol dependence: a systematic review and meta‐analysis

Previous studies have suggested that the effect of naltrexone in patients with alcohol dependence may be moderated by genetic factors. In particular, the possession of the G allele of the A118G polymorphism of the µ‐opioid receptor gene (OPRM1) has been associated with a better response to naltrexone, although controversial results have been reported. The aim of this paper is to combine previous findings by means of a systematic review and a meta‐analysis. We retrieved studies on the relationship between A118G polymorphism in OPRM1 gene and response to treatment with naltrexone in patients with alcohol dependence by means of electronic database search. A meta‐analysis was conducted using a random‐effects model. Calculations of odds ratio (OR) and their confidence intervals (CI) and tests for heterogeneity of the results have been performed. Six previous studies have analyzed the role of A118G polymorphism in response to naltrexone for alcohol dependence. After meta‐analysis, we found that naltrexone‐treated patients carrying the G allele had lower relapse rates than those who were homozygous for the A allele (OR: 2.02, 95% CI 1.26–3.22; P = 0.003). There were no differences in abstinence rates. Our results support the fact that the G allele of A118G polymorphism of OPRM1 moderates the effect of naltrexone in patients with alcohol dependence. This genetic marker may therefore identify a subgroup of individuals more likely to respond to this treatment.

Extensive characterization of the immunophenotype and pattern of cytokine production by distinct subpopulations of normal human peripheral blood MHC II+/lineage- cells

Dendritic cells (DC) represent the most powerful professional antigen‐presenting cells (APC) in the immune system. The aim of the present study was to analyse, on a single‐cell basis by multiparametric flow cytometry with simultaneous four‐colour staining and a two‐step acquisition procedure, the immunophenotypic profile and cytokine production of DC from 67 normal whole peripheral blood (PB) samples. Two clearly different subsets of HLA‐II+/lineage− were identified on the basis of their distinct phenotypic characteristics: one DC subset was CD33strong+ and CD123dim+ (0.16 ± 0.06% of the PB nucleated cells and 55.9 ± 11.9% of all PB DC) and the other, CD33dim+ and CD123strong+ (0.12 ± 0.04% of PB nucleated cells and 44.53 ± 11.5% of all PB DC). Moreover, the former DC subpopulation clearly showed higher expression of the CD13 myeloid‐associated antigen, the CD29 and CD58 adhesion molecules, the CD2, CD5 and CD86 costimulatory molecules, the CD32 IgG receptor and the CD11c complement receptor. In addition, these cells showed stronger HLA‐DR and HLA‐DQ expression and a higher reactivity for the IL‐6 receptor α‐chain (CD126) and for CD38. In contrast, the CD123strong+/CD33dim+ DC showed a stronger reactivity for the CD4 and CD45RA molecules, whereas they did not express the CD58, CD5, CD11c and CD13 antigens. Regarding cytokine production, our results show that while the CD33strong+/CD123dim+ DC are able to produce significant amounts of inflammatory cytokines, such as IL‐1β (97 ± 5% of positive cells), IL‐6 (96 ± 1.1% of positive cells), IL‐12 (81.5 ± 15.5% of positive cells) and tumour necrosis factor‐alpha (TNF‐α) (84 ± 22.1% of positive cells) as well as chemokines such as IL‐8 (99 ± 1% of positive cells), the functional ability of the CD123strong+/CD33dim+ DC subset to produce cytokines under the same conditions was almost null. Our results therefore clearly show the presence of two distinct subsets of DC in normal human PB, which differ not only in their immunophenotype but also in their functionality, as regards cytokine production.

Flow cytometric analysis of cytokine production by normal human peripheral blood dendritic cells and monocytes: Comparative analysis of different stimuli, secretion-blocking agents and incubation periods

In this paper, we comparatively analyze the effects of the following different stimuli on the production and intracellular accumulation of the interleukin (IL)-1 beta, IL-6, IL-12, tumor necrosis factor-alpha (TNF-alpha), and IL-8 inflammatory cytokines in both normal human peripheral blood (PB) dendritic cell (DC) subsets and monocytes: lipopolysaccharide (LPS) versus Staphylococcus aureus cowan I (SAC) in the presence or absence of interferon-(IFN)-gamma-, cytokine secretion-blocking agents (brefeldin A alone versus brefeldin A plus monensin), and incubation periods (6, 12, and 24 h). For this purpose, a four-color multiple-staining direct immunofluorescence technique analyzed by flow cytometry was systematically used in all experiments (n = 19). Our results show that after stimulation, an important proportion of each of the two CD33(+) myeloid DC subsets as well as the monocytes produce significant amounts of all cytokines analyzed under each of the experimental conditions assayed. In contrast, CD33(-/+lo) lymphoplasmocytoid DC failed to produce detectable levels of any of the above-mentioned cytokines under the same stimulatory conditions. Upon comparing the different stimuli used, LPS was associated with higher percentages of cytokine-producing cells compared with SAC, especially within the CD33(hi) DC subset; interestingly, the addition of IFN-gamma enhanced the response of monocytes to both LPS and SAC. As regards the secretion-blocking agents, brefeldin A alone was superior to the combination of brefeldin A and monensin. This is because it was frequently associated with both a higher percentage of cytokine-positive cells and greater amounts of detectable cytokines per cell. Sequential analysis of cytokine production by PB DC and monocytes after 6, 12, and 24 h of cell culture showed that after 6 h, an increased cell death rate existed among DC, which became even undetectable at 24 h, in the absence of a significant increase in cytokine secretion. In summary, our results show that from the experimental conditions assayed in this paper, to induce cytokine production by normal human DC and monocytes, maximum response is obtained once PB samples are stimulated for 6 h with LPS (with or without IFN-gamma) in the presence of brefeldin A alone.

Tumor Necrosis Factor Polymorphisms and Alcoholic Liver Disease: A HuGE Review and Meta-Analysis

The association between alcoholic liver disease (ALD) and tumor necrosis factor-alpha gene (TNFA) polymorphisms has been analyzed in several studies, but results have been conflicting. The main purpose of this study was to integrate previous findings and explore whether these polymorphisms are associated with susceptibility to ALD. The authors surveyed studies on the relation between TNFA gene polymorphisms and ALD by means of an electronic database search. A meta-analysis was conducted in a random-effects model. The association between ALD and the -238G>A or -308G>A polymorphism of the TNFA gene has been analyzed in 11 studies. Concerning the -238G>A polymorphism, the authors found a significant association between possession of the A allele and risk of alcoholic liver cirrhosis (odds ratio = 1.47, 95% confidence interval: 1.05, 2.07). Meta-analysis of the relation between the -308G>A polymorphism and ALD did not show any significant association. Given the limited number of studies and the potential biases, more data are needed to confirm the association described for the -238A allele.

Long lasting immunological effects of ethanol after withdrawal

The aim of the present study was to analyze on chronic alcoholic patients the effect of ethanol (EtOH) withdrawal on the immune system through the investigation of the distribution of PB lymphoid subsets, using multiple-stainings with monoclonal antibodies and flow cytometry. For this purpose a group of 20 patients with active alcoholism without liver disease, negative for hepatitis virus, and without malnutrition was analyzed and followed for 9 months after alcohol consumption had been discontinued. Twenty-five age- and sex-matched healthy volunteers were included in the study. The following panel of monoclonal antibodies combinations (FITC/PE/PerCP or PE-Cy5) was used: TCR alpha beta/CD3/HLA DR, CD25/CD56/CD3, TCR gamma delta/CD3/HLA DR, CD45RA/CD45R0/CD4, CD3/CD8, CD19/CD5, and CD3/CD11c. Analysis was performed on at least 1,500 events/tube at flow cytometry using the Lysys II software program. During the alcohol intake period, the most striking findings were a significant (P < 0.05) expansion of the CD8+ T-lymphocyte subset, which coexpresses the activation associated antigens HLA DR and CD11c, as well as a significant increase in both NK-cells (CD3-/CD56+) and the T-cell subset with NK activity coexpressing CD3 and CD56 (P < 0.05 and P < 0.01, respectively). In addition, a decrease in the CD5+ B-cells (P < 0.05), associated with reduced serum gamma-globulin levels, was also observed. During alcohol withdrawal, a rapid decrease towards normal values of activated CD8+/HLA DR+ and CD11c+ T-lymphocytes was observed as well as a normalization of CD19+/CD5+ B-cells and gamma-globulin serum levels; these changes might be directly related to EtOH suppression. Surprisingly, however, new immunological imbalances emerged in spite of the absence of alcohol intake. Thus, a progressive and significant expansion (P < 0.05) of CD4+ T-cells associated with an increased expression of the CD25 activation-related antigen and a preferential use of the CD45R0 isoform by CD4+ T-cells were observed. In parallel, there was an even more evident increase (P < 0.01) in the number of PB NK-cells. Our results show that EtOH consumption induces changes in the immune system, its effects persisting or even becoming more evident after suppression of EtOH intake for a 9 month period.

Cannabinoid Receptor 1 Gene is Associated with Alcohol Dependence

BACKGROUND Alcohol dependence (AD) vulnerability is determined by a complex array of genetic factors. Given the potential role of endocannabinoid system in AD, polymorphisms within cannabinoid receptor 1 gene (CNR1) have been potentially associated with susceptibility to this disease. We thus aimed to examine the relationship between 3 allelic variants of CNR1 (rs6454674, rs1049353, and rs806368) and AD. METHODS Genotyping of the aforementioned polymorphisms was carried out by PCR in 298 male alcoholics (187 of them with AD) and 155 healthy controls. Single-marker, haplotype, and interaction analysis were performed to analyze the influence of CNR1 gene on AD susceptibility. RESULTS We found an association between CNR1 gene and AD after haplotype analysis. Alcoholic patients with TGT haplotype (corresponding to rs6454674-rs1049353-rs806368 polymorphisms in this order) were less prone to have AD (p = 0.017). Besides, alcoholics with a G/T substitution of the first marker (GGT haplotype) or a C/T substitution of the third marker (TGC haplotype) were more likely to develop AD (p = 0.006 and 0.004, respectively) and an interaction was found between the G allele of rs6454674 single nucleotide polymorphism (SNP) and the C allele of rs806368 SNP (p = 0.009). CONCLUSIONS Our findings support previously reported associations of CNR1 with dependence to alcohol and other substances and emphasizes the relevance of endocannabinoid system in AD.

Alcoholic liver cirrhosis is associated with a decreased expression of the CD28 costimulatory molecule, a lower ability of T cells to bind exogenous IL-2, and increased soluble CD8 levels.

Despite the existence of high interleukin (IL)-12 serum levels in patients with chronic active alcoholism, previous studies from our group have shown that, during active ethanol intake, alcoholic patients with alcoholic liver cirrhosis (ALC) display an impaired T-helper-1 response together with abnormalities in the peripheral blood (PB) cytotoxic compartment. The aim of the present study was to gain further insights into the mechanisms underlying these abnormalities. For that purpose, we analyzed the expression on PB B- and T-cell subsets of both the CD28 and CD80 costimulatory molecules, the ability of T lymphocytes to bind to exogenous recombinant IL-2, and the serum levels of soluble CD8 (sCD8) that might interfere with CD8+ T-cell activation in a group of 10 ALC patients with active ethanol intake (ALCET group). As reference groups, we analyzed 10 healthy individuals, 10 chronic alcoholic patients without liver disease (AWLD group) but with active ethanol intake, and 10 ALC patients who had quit drinking for at least 1 year. Our results showed that ALCET patients display a significant decrease in the number of PB CD28+/CD8(hi) T cells (P < 0.05) and CD80+ B cells (P < 0.01) compared with both healthy controls and AWLD patients. In addition, in ALCET patients, PB T cells also showed a decreased ability to bind to exogenous IL-2 (P < 0.01). This was associated with the existence of increased serum levels of sCD8 in ALC patients, the highest levels being detected in the ALCET group (P < 0.01). Altogether, our results point to the existence of several abnormalities that would affect the cytotoxic response in ALCET patients.

Gender differences in the inflammatory cytokine and chemokine profiles induced by binge ethanol drinking in adolescence

Heavy binge drinking in adolescence can cause long‐term cognitive and behavioral dysfunctions. Recent experimental evidence indicates the participation of immune system activation in the effects of ethanol in the adolescent brain and suggests gender differences. The present study aims to assess plasma cytokine and chemokine levels in male and female adolescents and young adults during acute alcohol intoxication and to correlate these results with the toll‐like receptor 4 (TLR4) response. The potential role of the TLR4 signaling response was also assessed in plasma and prefrontal cortex (PFC) of adolescent wild‐type and TLR4‐knockout male and female mice with binge ethanol treatment. The results showed that alcohol intoxication increased the plasma levels of several cytokine and chemokine [interferon‐γ, interleukin (IL)‐10, IL‐17A, IL‐1β, IL‐2, IL‐4, IL‐6, IL‐8, fractalkine, monocyte chemoattractant protein 1 (MCP‐1) and macrophage inflammatory protein 1α (MIP‐1α)] and the upregulation of TLR4 mRNA levels occurred in intoxicated females, while elevation of colony‐stimulating factor was only observed in the plasma of males. In wild‐type female adolescent mice, intermittent ethanol treatment increased the levels of several cytokines (IL‐17A and IL‐1β) and chemokines (MCP‐1, MIP‐1α and fractalkine) in PFC and in serum (IL‐17A, MCP‐1 and MIP‐1α), but significant differences in the fractalkine levels in PFC were observed only in male mice. No changes in serum or prefrontal cortex cytokine and chemokine levels were noted in ethanol‐treated male or female TLR4‐knockout mice. Our findings revealed that females are more vulnerable than males to inflammatory effects of binge ethanol drinking and suggested that TLR4 is an important target of ethanol‐induced inflammation and neuroinflammation in adolescence.

Prevalence of Hepatitis C Virus Infection in Alcoholic Patients: Cohort Study and Systematic Review

AIMS Prevalence of chronic hepatitis C virus (HCV) infection among alcoholics is thought to be higher than in the general population, although prevalence rates reported are quite variable. Our study is aimed to analyze HCV prevalence in a cohort of alcoholics and to perform a systematic review on this topic. PATIENTS AND METHODS A total of 396 alcoholic patients consecutively referred to our Alcoholism Unit were included. HCV infection status and other clinical variables were recorded for each patient. Variables associated with HCV infection were analyzed by means of logistic regression. Additionally, we performed a systematic review focused on previous studies on this topic. RESULTS Among our alcoholic patients, 14 of them (3.53%) had chronic HCV infection. Variables independently associated with HCV infection were female gender, injection drug use (IDU) and the presence of alcoholic liver disease (ALD). Twenty-four studies analyzing HCV prevalence in alcoholic patients were included in our systematic review, showing prevalence rates of HCV infection ranging from 2.1 to 51% and an average weighted prevalence of 16.32%. CONCLUSION In our series, the prevalence rate of chronic HCV infection among alcoholic patients is lower than previously reported, which is probably explained by the relatively low number of patients with ALD or IDU in our sample. Prevalence rates previously published are quite different and the presence of ALD and/or IDU can act as confounding factors for HCV prevalence among alcoholics.

Common polymorphisms in interleukin genes (IL4, IL6, IL8 and IL12) are not associated with alcoholic liver disease or alcoholism in Spanish men.

BACKGROUND Preliminary data suggest that polymorphisms in cytokine genes may be involved in the genetic predisposition to alcoholic liver cirrhosis or alcohol use disorders. We thus analyze the association between these diseases and the following polymorphisms: -33T>C IL4, -174 G>C IL6, -251 T>A IL8 and 1188 A>C IL12B. METHODS 258 male alcoholics (161 without liver disease and 97 with liver cirrhosis) and 101 healthy controls were genotyped for the above mentioned polymorphisms. We examined the relationship between genotype and allele frequencies and the presence of disease, as well as the correlation with combinations of putative pro-inflammatory genotypes. Haplotypes were inferred using the expectation-maximization algorithm and haplotype frequencies were compared. RESULTS We found no statistically significant association between any of these polymorphisms or the combinations of pro-inflammatory polymorphisms and the risk of alcoholic liver cirrhosis or alcohol abuse or dependence. Haplotype analysis of the IL4 and IL12B polymorphisms did not show any statistical relationship either. CONCLUSIONS Our results do not support the hypothesis that the analyzed polymorphisms confer differences in alcoholic liver cirrhosis or alcohol use disorders susceptibility.