The endogenous opioid peptides dynorphins and enkephalins may be involved in brain-area specific ... more The endogenous opioid peptides dynorphins and enkephalins may be involved in brain-area specific synaptic adaptations relevant for different stages of an addiction cycle. We compared the levels of prodynorphin (PDYN) and proenkephalin (PENK) mRNAs (by qRT-PCR), and dynorphins and enkephalins (by radioimmunoassay) in the caudate nucleus and putamen between alcoholics and control subjects. We also evaluated whether PDYN promoter variant rs1997794 associated with alcoholism affects PDYN expression. Postmortem specimens obtained from 24 alcoholics and 26 controls were included in final statistical analysis. PDYN mRNA and Met-enkephalin-Arg-Phe, a marker of PENK were downregulated in the caudate of alcoholics, while PDYN mRNA and Leu-enkephalin-Arg, a marker of PDYN were decreased in the putamen of alcoholics carrying high risk rs1997794 C allele. Downregulation of opioid peptides in the dorsal striatum may contribute to development of alcoholism including changes in goal directed behavior and formation of a compulsive habit in alcoholics.
Cigarette smoking among female and male alcoholics has not been extensively studied as a factor r... more Cigarette smoking among female and male alcoholics has not been extensively studied as a factor related to intensity of alcohol craving during residential treatment and corresponding sobriety length. This retrospective cohort study assessed self-reported sobriety outcomes in patients with alcohol dependence at 3-month intervals over 12 months after completion of a 30-day residential treatment program. Demographic and clinical variables were collected including smoking status, alcohol craving utilizing the Penn Alcohol Craving Scale (PACS), and alcohol relapse. Statistical analyses included Chi-square, ANOVA, Tukey's test, Kaplan-Meier plots and Cox proportional hazards models as appropriate. Of the 761 alcohol-dependent study subjects, 355 (47%) were current smokers. Alcohol craving intensity was higher in smoking females compared to nonsmoking females (p=0.0096), smoking males (p<0.0001), and nonsmoking males (p<0.0001). Smoking status-by-sex interaction was not associated with post-treatment relapse. After controlling for other variables, higher PACS scores at admission were associated with higher probability of relapse (p=0.0003). In this study, female alcoholic smokers experienced the highest level of alcohol craving in an alcohol treatment setting. Interestingly, this did not translate into higher rates of post-treatment relapse. Further research is warranted to explore the neurobiological basis for sex differences in this highly prevalent comorbidity.
Acamprosate has been widely used since the Food and Drug Administration approved the medication f... more Acamprosate has been widely used since the Food and Drug Administration approved the medication for treatment of alcohol use disorders (AUDs) in 2004. Although the detailed molecular mechanism of acamprosate remains unclear, it has been largely known that acamprosate inhibits glutamate action in the brain. However, AUD is a complex and heterogeneous disorder. Thus, biomarkers are required to prescribe this medication to patients who will have the highest likelihood of responding positively. To identify pharmacometabolomic biomarkers of acamprosate response, we utilized serum samples from 120 alcohol-dependent subjects, including 71 responders (maintained continuous abstinence) and 49 non-responders (any alcohol use) during 12 weeks of acamprosate treatment. Notably, baseline serum glutamate levels were significantly higher in responders compared with non-responders. Importantly, serum glutamate levels of responders are normalized after acamprosate treatment, whereas there was no sig...
We previously demonstrated that prodynorphin (PDYN) haplotypes and single nucleotide polymorphism... more We previously demonstrated that prodynorphin (PDYN) haplotypes and single nucleotide polymorphism (SNP) rs2281285 are associated with alcohol dependence and the propensity to drink in negative emotional states, and recent studies suggest that PDYN gene effects on substance dependence risk may be sex-related. We examined sex-dependent associations of PDYN variation with alcohol dependence and related phenotypes, including negative craving, time until relapse after treatment and the length of sobriety episodes before seeking treatment, in discovery and validation cohorts of European ancestry. We found a significant haplotype-by-sex interaction (p = 0.03), suggesting association with alcohol dependence in males (p = 1E-4) but not females. The rs2281285 G allele increased risk for alcohol dependence in males in the discovery cohort (OR = 1.49, p = 0.002), with a similar trend in the validation cohort (OR = 1.35, p = 0.086). However, rs2281285 showed a trend towards association with in...
Recent reports have suggested an association between variation in the serotonin transporter and p... more Recent reports have suggested an association between variation in the serotonin transporter and primary pulmonary hypertension and myocardial infarction. We set out to determine whether these associations were present in a population of patients who underwent SLC6A4 genotyping and to explore whether genetic variation in the serotonin transporter might be also associated with other cardiovascular functional and structural abnormalities. Included were 3473 patients who were genotyped for the SLC6A4 5HTTLPR polymorphism and a subset for rs25531 (n=816) and STin2 (n=819). An association was observed between 5HTTLPR and primary pulmonary hypertension (p=0.0130), anomalies of the cerebrovascular system (p<0.0001), and other anomalies of great veins (p=0.0359). The combined 5HTTLPR and rs25531 genotype was associated with tachycardia (p=0.0123). There was an association of the STin2 genotype with abnormal electrocardiogram (ECG) (p=0.0366) and abnormal cardiac study (0.0311). Overall, these results represent a step toward the understanding of the impact of SLC6A4 variation on cardiovascular pathology.
Genome-wide association studies (GWAS) have revealed many single nucleotide polymorphisms (SNPs) ... more Genome-wide association studies (GWAS) have revealed many single nucleotide polymorphisms (SNPs) associated with complex traits. Although these studies frequently fail to identify statistically significant associations, the top association signals from GWAS may be enriched for true associations. We therefore investigated the association of alcohol dependence with 43 SNPs selected from association signals in the first two published GWAS of alcoholism. Our analysis of 808 alcohol-dependent cases and 1,248 controls provided evidence of association of alcohol dependence with SNP rs1614972 in the ADH1C gene (unadjusted p = 0.0017). Because the GWAS study that originally reported association of alcohol dependence with this SNP [1] included only men, we also performed analyses in sex-specific strata. The results suggest that this SNP has a similar effect in both sexes (men: OR (95%CI) = 0.80 (0.66, 0.95); women: OR (95%CI) = 0.83 (0.66, 1.03)). We also observed marginal evidence of association of the rs1614972 minor allele with lower alcohol consumption in the non-alcoholic controls (p = 0.081), and independently in the alcohol-dependent cases (p = 0.046). Despite a number of potential differences between the samples investigated by the prior GWAS and the current study, data presented here provide additional support for the association of SNP rs1614972 in ADH1C with alcohol dependence and extend this finding by demonstrating association with consumption levels in both non-alcoholic and alcohol-dependent populations. Further studies should investigate the association of other polymorphisms in this gene with alcohol dependence and related alcohol-use phenotypes.
One of the proposed psychobiological pathways of craving attributes the desire for drinking in th... more One of the proposed psychobiological pathways of craving attributes the desire for drinking in the context of tension, discomfort or unpleasant emotions, to "negative" (or "relief") craving. The aim of this study was to replicate a previously reported association of the PDYN rs2281285 variant with negative craving using a different phenotyping approach. The TaqMan® Genotyping Assay was used to genotype the rs2281285 variant in 417 German alcohol-dependent subjects. The presence of negative/relief craving was assessed by asking if participants ever ingested alcohol to avoid unwanted emotional or somatic discomfort. The minor allele of rs2281285 was associated with an increased risk of drinking to avoid/escape unwanted emotional or somatic events (OR=2.29, 95% CI=1.08-4.85, p=0.0298). Despite the use of a different phenotyping approach to the measurement of negative craving, our results confirm the association between negative craving and PDYN rs2281285. Genetic markers of negative craving may help to identify subgroups of alcohol-dependent individuals vulnerable to relapse in the context of negative emotions or somatic discomfort, leading to the development of specifically tailored treatment strategies.
ABSTRACT Craving in negative emotional situations (negative craving) is commonly associated with ... more ABSTRACT Craving in negative emotional situations (negative craving) is commonly associated with relapse and heavy alcohol use. Elevated dynorphin levels were associated with negative emotions, while variations in the OPRK1 and PDYN genes encoding OPRK1 receptor and dynorphins were associated with alcohol dependence.Objectives To investigate potential overlap in the genetic factors underlying, negative craving and alcohol dependence.AimsExamine the association of the negative craving and genetic variation in the OPRK1 and PDYN genes.Methods13 PDYN and 10 OPRK1 Single Nucleotide Polymorphisms (SNPs), including those previously reported to be associated with alcohol dependence were genotyped in 196 alcohol dependent subjects. The raw scores of the negative subscale of Inventory of Drug Taking Situations (IDTS) were utilized as a quantitative measure of negative craving. Logistic regression models were used to test for associations after controlling for age and gender.ResultsGene-level haplotype testing demonstrated significant association of negative craving with variation in PDYN (p < 0.05) but not OPRK1 gene. The rs2281285 - rs199794 haplotype showed significant association (p = 0.0236) with negative craving, while rs2235749 - rs10485703 haplotype showed marginally significant association (p = 0.055). This replicates previous findings of association between these haplotypes and alcohol dependence. Negative craving was also associated with PDYN rs2281285 variant (p = 0.012) with estimated effect size of 6.95 (SE = 2.75). This new association finding was not significant after correction for multiple testing (p = 0.18).Conclusions Our findings support association of PDYN sequence variation with negative craving in alcohol dependent subjects. Future studies should investigate functional mechanisms of this association.
Alcoholism: Clinical and Experimental Research, 2011
Alcohol consumption is associated with a broad array of physiologic and behavioral effects includ... more Alcohol consumption is associated with a broad array of physiologic and behavioral effects including changes in heart rate. However, the physiologic mechanisms of alcohol effects and the reasons for individual differences in the cardiac response remain unknown. Measuring changes in resting heart rate (measured as beats/min) has not been found to be as sensitive to alcohol's effects as changes in heart rate variability (HRV). HRV is defined as fluctuations in interbeat interval length which reflect the heart's response to extracardiac factors that affect heart rate. HRV allows simultaneous assessment of both sympathetic and parasympathetic activity and the interplay between them. Increased HRV has been associated with exercise and aerobic fitness, while decreased HRV has been associated with aging, chronic stress, and a wide variety of medical and psychiatric disorders. Decreased HRV has predictive value for mortality in general population samples and patients with myocardial infarction and used as an indicator of altered autonomic function. A significant inverse correlation was found between HRV and both the severity of depression and the duration of the depressive episode. HRV analysis provides insights into mechanisms of autonomic regulation and is extensively used to clarify relationships between depression and cardiovascular disease. This article will review the methodology of HRV measurements and contemporary knowledge about effects of acute alcohol consumption on HRV. Potential implications of this research include HRV response to alcohol that could serve as a marker for susceptibility to alcoholism. At present however there is almost no research data supporting this hypothesis.
The endogenous opioid peptides dynorphins and enkephalins may be involved in brain-area specific ... more The endogenous opioid peptides dynorphins and enkephalins may be involved in brain-area specific synaptic adaptations relevant for different stages of an addiction cycle. We compared the levels of prodynorphin (PDYN) and proenkephalin (PENK) mRNAs (by qRT-PCR), and dynorphins and enkephalins (by radioimmunoassay) in the caudate nucleus and putamen between alcoholics and control subjects. We also evaluated whether PDYN promoter variant rs1997794 associated with alcoholism affects PDYN expression. Postmortem specimens obtained from 24 alcoholics and 26 controls were included in final statistical analysis. PDYN mRNA and Met-enkephalin-Arg-Phe, a marker of PENK were downregulated in the caudate of alcoholics, while PDYN mRNA and Leu-enkephalin-Arg, a marker of PDYN were decreased in the putamen of alcoholics carrying high risk rs1997794 C allele. Downregulation of opioid peptides in the dorsal striatum may contribute to development of alcoholism including changes in goal directed behavior and formation of a compulsive habit in alcoholics.
Cigarette smoking among female and male alcoholics has not been extensively studied as a factor r... more Cigarette smoking among female and male alcoholics has not been extensively studied as a factor related to intensity of alcohol craving during residential treatment and corresponding sobriety length. This retrospective cohort study assessed self-reported sobriety outcomes in patients with alcohol dependence at 3-month intervals over 12 months after completion of a 30-day residential treatment program. Demographic and clinical variables were collected including smoking status, alcohol craving utilizing the Penn Alcohol Craving Scale (PACS), and alcohol relapse. Statistical analyses included Chi-square, ANOVA, Tukey's test, Kaplan-Meier plots and Cox proportional hazards models as appropriate. Of the 761 alcohol-dependent study subjects, 355 (47%) were current smokers. Alcohol craving intensity was higher in smoking females compared to nonsmoking females (p=0.0096), smoking males (p<0.0001), and nonsmoking males (p<0.0001). Smoking status-by-sex interaction was not associated with post-treatment relapse. After controlling for other variables, higher PACS scores at admission were associated with higher probability of relapse (p=0.0003). In this study, female alcoholic smokers experienced the highest level of alcohol craving in an alcohol treatment setting. Interestingly, this did not translate into higher rates of post-treatment relapse. Further research is warranted to explore the neurobiological basis for sex differences in this highly prevalent comorbidity.
Acamprosate has been widely used since the Food and Drug Administration approved the medication f... more Acamprosate has been widely used since the Food and Drug Administration approved the medication for treatment of alcohol use disorders (AUDs) in 2004. Although the detailed molecular mechanism of acamprosate remains unclear, it has been largely known that acamprosate inhibits glutamate action in the brain. However, AUD is a complex and heterogeneous disorder. Thus, biomarkers are required to prescribe this medication to patients who will have the highest likelihood of responding positively. To identify pharmacometabolomic biomarkers of acamprosate response, we utilized serum samples from 120 alcohol-dependent subjects, including 71 responders (maintained continuous abstinence) and 49 non-responders (any alcohol use) during 12 weeks of acamprosate treatment. Notably, baseline serum glutamate levels were significantly higher in responders compared with non-responders. Importantly, serum glutamate levels of responders are normalized after acamprosate treatment, whereas there was no sig...
We previously demonstrated that prodynorphin (PDYN) haplotypes and single nucleotide polymorphism... more We previously demonstrated that prodynorphin (PDYN) haplotypes and single nucleotide polymorphism (SNP) rs2281285 are associated with alcohol dependence and the propensity to drink in negative emotional states, and recent studies suggest that PDYN gene effects on substance dependence risk may be sex-related. We examined sex-dependent associations of PDYN variation with alcohol dependence and related phenotypes, including negative craving, time until relapse after treatment and the length of sobriety episodes before seeking treatment, in discovery and validation cohorts of European ancestry. We found a significant haplotype-by-sex interaction (p = 0.03), suggesting association with alcohol dependence in males (p = 1E-4) but not females. The rs2281285 G allele increased risk for alcohol dependence in males in the discovery cohort (OR = 1.49, p = 0.002), with a similar trend in the validation cohort (OR = 1.35, p = 0.086). However, rs2281285 showed a trend towards association with in...
Recent reports have suggested an association between variation in the serotonin transporter and p... more Recent reports have suggested an association between variation in the serotonin transporter and primary pulmonary hypertension and myocardial infarction. We set out to determine whether these associations were present in a population of patients who underwent SLC6A4 genotyping and to explore whether genetic variation in the serotonin transporter might be also associated with other cardiovascular functional and structural abnormalities. Included were 3473 patients who were genotyped for the SLC6A4 5HTTLPR polymorphism and a subset for rs25531 (n=816) and STin2 (n=819). An association was observed between 5HTTLPR and primary pulmonary hypertension (p=0.0130), anomalies of the cerebrovascular system (p<0.0001), and other anomalies of great veins (p=0.0359). The combined 5HTTLPR and rs25531 genotype was associated with tachycardia (p=0.0123). There was an association of the STin2 genotype with abnormal electrocardiogram (ECG) (p=0.0366) and abnormal cardiac study (0.0311). Overall, these results represent a step toward the understanding of the impact of SLC6A4 variation on cardiovascular pathology.
Genome-wide association studies (GWAS) have revealed many single nucleotide polymorphisms (SNPs) ... more Genome-wide association studies (GWAS) have revealed many single nucleotide polymorphisms (SNPs) associated with complex traits. Although these studies frequently fail to identify statistically significant associations, the top association signals from GWAS may be enriched for true associations. We therefore investigated the association of alcohol dependence with 43 SNPs selected from association signals in the first two published GWAS of alcoholism. Our analysis of 808 alcohol-dependent cases and 1,248 controls provided evidence of association of alcohol dependence with SNP rs1614972 in the ADH1C gene (unadjusted p = 0.0017). Because the GWAS study that originally reported association of alcohol dependence with this SNP [1] included only men, we also performed analyses in sex-specific strata. The results suggest that this SNP has a similar effect in both sexes (men: OR (95%CI) = 0.80 (0.66, 0.95); women: OR (95%CI) = 0.83 (0.66, 1.03)). We also observed marginal evidence of association of the rs1614972 minor allele with lower alcohol consumption in the non-alcoholic controls (p = 0.081), and independently in the alcohol-dependent cases (p = 0.046). Despite a number of potential differences between the samples investigated by the prior GWAS and the current study, data presented here provide additional support for the association of SNP rs1614972 in ADH1C with alcohol dependence and extend this finding by demonstrating association with consumption levels in both non-alcoholic and alcohol-dependent populations. Further studies should investigate the association of other polymorphisms in this gene with alcohol dependence and related alcohol-use phenotypes.
One of the proposed psychobiological pathways of craving attributes the desire for drinking in th... more One of the proposed psychobiological pathways of craving attributes the desire for drinking in the context of tension, discomfort or unpleasant emotions, to "negative" (or "relief") craving. The aim of this study was to replicate a previously reported association of the PDYN rs2281285 variant with negative craving using a different phenotyping approach. The TaqMan® Genotyping Assay was used to genotype the rs2281285 variant in 417 German alcohol-dependent subjects. The presence of negative/relief craving was assessed by asking if participants ever ingested alcohol to avoid unwanted emotional or somatic discomfort. The minor allele of rs2281285 was associated with an increased risk of drinking to avoid/escape unwanted emotional or somatic events (OR=2.29, 95% CI=1.08-4.85, p=0.0298). Despite the use of a different phenotyping approach to the measurement of negative craving, our results confirm the association between negative craving and PDYN rs2281285. Genetic markers of negative craving may help to identify subgroups of alcohol-dependent individuals vulnerable to relapse in the context of negative emotions or somatic discomfort, leading to the development of specifically tailored treatment strategies.
ABSTRACT Craving in negative emotional situations (negative craving) is commonly associated with ... more ABSTRACT Craving in negative emotional situations (negative craving) is commonly associated with relapse and heavy alcohol use. Elevated dynorphin levels were associated with negative emotions, while variations in the OPRK1 and PDYN genes encoding OPRK1 receptor and dynorphins were associated with alcohol dependence.Objectives To investigate potential overlap in the genetic factors underlying, negative craving and alcohol dependence.AimsExamine the association of the negative craving and genetic variation in the OPRK1 and PDYN genes.Methods13 PDYN and 10 OPRK1 Single Nucleotide Polymorphisms (SNPs), including those previously reported to be associated with alcohol dependence were genotyped in 196 alcohol dependent subjects. The raw scores of the negative subscale of Inventory of Drug Taking Situations (IDTS) were utilized as a quantitative measure of negative craving. Logistic regression models were used to test for associations after controlling for age and gender.ResultsGene-level haplotype testing demonstrated significant association of negative craving with variation in PDYN (p < 0.05) but not OPRK1 gene. The rs2281285 - rs199794 haplotype showed significant association (p = 0.0236) with negative craving, while rs2235749 - rs10485703 haplotype showed marginally significant association (p = 0.055). This replicates previous findings of association between these haplotypes and alcohol dependence. Negative craving was also associated with PDYN rs2281285 variant (p = 0.012) with estimated effect size of 6.95 (SE = 2.75). This new association finding was not significant after correction for multiple testing (p = 0.18).Conclusions Our findings support association of PDYN sequence variation with negative craving in alcohol dependent subjects. Future studies should investigate functional mechanisms of this association.
Alcoholism: Clinical and Experimental Research, 2011
Alcohol consumption is associated with a broad array of physiologic and behavioral effects includ... more Alcohol consumption is associated with a broad array of physiologic and behavioral effects including changes in heart rate. However, the physiologic mechanisms of alcohol effects and the reasons for individual differences in the cardiac response remain unknown. Measuring changes in resting heart rate (measured as beats/min) has not been found to be as sensitive to alcohol's effects as changes in heart rate variability (HRV). HRV is defined as fluctuations in interbeat interval length which reflect the heart's response to extracardiac factors that affect heart rate. HRV allows simultaneous assessment of both sympathetic and parasympathetic activity and the interplay between them. Increased HRV has been associated with exercise and aerobic fitness, while decreased HRV has been associated with aging, chronic stress, and a wide variety of medical and psychiatric disorders. Decreased HRV has predictive value for mortality in general population samples and patients with myocardial infarction and used as an indicator of altered autonomic function. A significant inverse correlation was found between HRV and both the severity of depression and the duration of the depressive episode. HRV analysis provides insights into mechanisms of autonomic regulation and is extensively used to clarify relationships between depression and cardiovascular disease. This article will review the methodology of HRV measurements and contemporary knowledge about effects of acute alcohol consumption on HRV. Potential implications of this research include HRV response to alcohol that could serve as a marker for susceptibility to alcoholism. At present however there is almost no research data supporting this hypothesis.
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Papers by Victor Karpyak