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Markus Heilig

Publications and source records attributed to Markus Heilig.

At least 19 recordsLinked to original sources
PubMed2025

Global Changes in Gene Expression and Splicing in Alcoholic Liver Disease.

Alcohol use disorder is a widespread illness commonly leading to alcoholic liver disease (ALD) and cirrhosis with an increased incidence of hepatocellular carcinoma (HCC), but the mechanisms of alcohol-related oncogenesis in the liver are incompletely understood. We tested the hypothesis that ALD predisposes to HCC via dysregulation of splicing. RNA sequencing was performed on liver biopsies from patients with different stages of ALD: early alcoholic steatohepatitis (eASH), non-severe alcoholic hepatitis (nsAH), and severe alcoholic hepatitis (sAH); furthermore, explants were collected from patients who underwent liver transplantation due to sAH (exAH). We found that alcohol caused widespread changes in transcriptome in all stages of ALD: among ~ 58,000 analyzed genomic features, ~ 4,900 were altered in eASH, ~ 9,100 - in nsAH, 14,100 - in sAH, and ~ 14,300 - in exAH. We observed thousands of missplicing events in all hepatic conditions, with mutually exclusive exons (MEE) being the most common event and exon skipping (ES) - second most common event. Analysis of ~ 600,000 exons revealed that ALD is associated with a genome-wide effect on exon expression, with ~ 50,000 exons being differentially expressed in eASH, ~ 130,000 - in nsAH, ~ 150,000 - in sAH, and ~ 120,000 - in exAH. To determine whether alcohol directly perturbs splicing, we subjected rats to alcohol vapor for 7 weeks and found that the expression of multiple snRNAs was drastically decreased, while expression of splicing factors was not affected. Screening of oncogenes and tumor suppressors, commonly involved in HCC pathogenesis, revealed that ALD affected the hepatic expression and/or splicing of most of these cancer-related genes. In summary, it appears that alcohol causes profound genome-wide changes in gene expression and splicing in the liver, likely via affecting the spliceosome. This results in altered expression and missplicing of key oncogenes and tumor suppressors involved in HCC, suggesting a novel mechanism of oncogenesis in the liver of patients with ALD.

alcohol use disorder↗
PubMed2006

Neuroendocrine, cognitive and structural imaging characteristics of women on longterm sickleave with job stress-induced depression.

BACKGROUND: A recent increase in long-term sick leave (LTSL) in Sweden affects mostly women in the public sector. Depression-related diagnoses account for most of the increase, and work-related stress has been implicated. METHODS: We examined dexamethasone/corticotropin-releasing hormone (dex/CRH) test responses, magnetic resonance imaging measures of prefrontocortical and hippocampal volumes, and cognitive performance in 29 female subjects fulfilling three core criteria: 1) LTSL > 90 days; 2) unipolar depression or maladaptive stress reaction with depressed mood; 3) job-related stress given as a reason for disability. This group was compared with 28 healthy matched controls. RESULTS: The cortisol response to CRH differed markedly between the two groups (p = .002), with a dampened response in patients. This difference remained after removing subjects on antidepressant drugs (p = .006) or smokers (p = .003). Neither hippocampal nor prefrontocortical volumes differed. Performance on hippocampus-dependent declarative memory tests did not differ between groups, but the LTSL group had impaired working memory. CONCLUSIONS: Our most salient finding is an attenuated dex-CRH response in patients on LTSL due to job-stress related depression. This is opposite to what has been described in major depression. It remains to be established whether this impairment is the end result of prolonged stress exposure, or a pre-existing susceptibility factor.

Adult↗
PubMed2006

Pharmacological treatment of alcohol dependence: target symptoms and target mechanisms.

Alcoholism is a major public health problem and resembles, in many ways, other chronic relapsing medical conditions. At least 2 separate dimensions of its symptomatology offer targetable pathophysiological mechanisms. Systems that mediate positive reinforcement by alcohol are likely important targets in early stages of the disease, particularly in genetically susceptible individuals. In contrast, long term neuroadaptive changes caused by chronic alcohol use primarily appear to affect systems mediating negative affective states, and gain importance following a prolonged history of dependence. Feasibility of pharmacological treatment in alcoholism has been demonstrated by a first wave of drugs which consists of 3 currently approved medications, the aldehyde dehydrogenase blocker disulfiram, the opioid antagonist naltrexone (NTX) and the functional glutamate antagonist acamprosate (ACM). The treatment toolkit is likely to be expanded in the near future. This will improve overall efficacy and allow individualized treatment, ultimately taking in account the patient's genetic makeup. In a second wave, early human efficacy data are available for the 5HT3 antagonist ondansetron, the GABA-B agonist baclofen and the anticonvulsant topiramate. The third wave is comprised of compounds predicted to be effective based on a battery of animal models. Using such models, a short list of additional targets has accumulated sufficient preclinical validation to merit clinical development. These include the cannabinoid CB1 receptor, receptors modulating glutamatergic transmission (mGluR2, 3 and 5), and receptors for stress-related neuropeptides corticotropin releasing factor (CRF), neuropeptide Y (NPY) and nociceptin. Once novel treatments are developed, the field faces a major challenge to assure their delivery to patients.

Acamprosate↗
PubMed2006

Buprenorphine reduces alcohol drinking through activation of the nociceptin/orphanin FQ-NOP receptor system.

BACKGROUND: Activation of the NOP receptor by its endogenous ligand nociceptin/orphanin FQ reduces ethanol intake in genetically selected alcohol preferring Marchigian Sardinian alcohol preferring (msP) rats. Here we evaluated whether buprenorphine, a partial agonist at micro-opioid and NOP receptors, would reduce ethanol consumption in msP rats via activation of NOP receptors. METHODS: Marchigian Sardinian alcohol preferring rats trained to drink 10% alcohol 2 hours/day were injected with buprenorphine (.03, .3, 3.0, or 6.0 mg/kg intraperitoneally [IP]) 90 min before access to ethanol. RESULTS: Similar to prototypical micro-agonists, the two lowest doses of buprenorphine significantly increased ethanol consumption (p < .01); in contrast, the two highest doses reduced it (p < .05). Pretreatment with naltrexone (.25 mg/kg IP) prevented the increase of ethanol intake induced by .03 mg/kg of buprenorphine (p < .001) but did not affect the inhibition of ethanol drinking induced by 3.0 mg/kg of buprenorphine. Conversely, pretreatment with the selective NOP receptor antagonist UFP-101 (10.0 or 20.0 microg/rat) abolished the suppression of ethanol drinking by 3.0 mg/kg of buprenorphine. CONCLUSIONS: Buprenorphine has dualistic effects on ethanol drinking; low doses increase alcohol intake via stimulation of classic opioid receptors, whereas higher doses reduce it via activation of NOP receptors. We suggest that NOP agonistic properties of buprenorphine might be useful in the treatment of alcoholism.

Alcohol Drinking↗
PubMed2006

Genetic impairment of frontocortical endocannabinoid degradation and high alcohol preference.

Endocannabinoid signaling has recently been implicated in ethanol-seeking behavior. We analyzed the expression of endocannabinoid-related genes in key brain regions of reward and dependence, and compared them between the alcohol-preferring AA (Alko Alcohol) and nonpreferring ANA (Alko Non-Alcohol) rat lines. A decreased expression of fatty acid amidohydrolase (FAAH), the main endocannabinoid-degrading enzyme, was found in prefrontal cortex (PFC) of AA rats, and was accompanied by decreased enzyme activity in this region. Binding of the endocannabinoid-cannabinoid 1 (CB1) receptor ligand (3)[H]SR141716A, and [35S]GTPgammaS incorporation stimulated by the CB1 agonist WIN 55,212-2 were downregulated in the same area. Together, this suggests an overactive endocannabinoid transmission in the PFC of AA animals, and a compensatory downregulation of CB1 signaling. The functional role of impaired FAAH function for alcohol self-administration was validated in two independent ways. The CB1 antagonist SR141716A potently and dose-dependently suppressed self-administration in AA rats when given systemically, or locally into the PFC, but not in the striatum. Conversely, intra-PFC injections of the competitive FAAH inhibitor URB597 increased ethanol self-administration in nonselected Wistar rats. These results show for the first time that impaired FAAH function may confer a phenotype of high voluntary alcohol intake, and point to a FAAH both as a potential susceptibility factor and a therapeutic target.

Alcohol Drinking↗
PubMed2006

Identifying hazardous alcohol consumption during pregnancy: implementing a research-based model in real life.

AIMS: It has been repeatedly demonstrated that hazardous alcohol use during pregnancy is rarely detected in regular antenatal care, and that detection can be markedly improved using systematic screening. A major challenge is to translate research-based strategies into regular antenatal care. Here, we examined whether a screening strategy using the Alcohol Use Disorder Test (AUDIT) and time-line follow-back (TLFB) could be implemented under naturalistic conditions and within available resources; and whether it would improve detection to the extent previously shown in a research context. METHODS: Regular midwives at a large antenatal care clinic were randomized to receive brief training and then implement AUDIT and TLFB ("intervention"); or to a waiting-list control group continuing to deliver regular care ("control"). In the intervention-condition, AUDIT was used to collect data about alcohol use during the year preceding pregnancy, and TLFB to assess actual consumption during the first trimester. Data were collected from new admissions over 6 months. RESULTS: Drop out was higher among patients of the intervention group than control midwives, 14% (23/162) versus 0% (0/153), and p<0.0001. A one-day training session combined with continuous expert support was sufficient to implement systematic screening with AUDIT and TLFB largely within resources of regular antenatal care. The use of these instruments identified patients with hazardous consumption during the year preceding pregnancy i.e. AUDIT score 6 or higher (17%, 23/139), and patients with ongoing consumption exceeding 70 g/week and/or binge consumption according to TLFB (17%, 24/139), to a significantly higher degree than regular antenatal screening (0/162). The AUDIT- and TLFB-positive populations overlapped partially, with 36/139 subjects screening positive with either of the instrument and 11/139 were positive for both. CONCLUSIONS: We confirm previous findings that alcohol use during pregnancy is more extensive in Sweden than has generally been realized. Systematic screening using AUDIT and TLFB detects hazardous use in a manner which regular antenatal care does not. This remains true under naturalistic conditions, following minimal training of regular antenatal care staff, and can be achieved with minimal resources. The proposed strategy appears attractive for broad implementation.

Adult↗
PubMed2005

Anxiolytic-like actions of centrally-administered neuropeptide Y, but not galanin, in C57BL/6J mice.

Neuropeptide Y (NPY) and galanin (GAL) are densely localized in brain regions subserving stress, fear and anxiety. While previous research supports a role for both neuropeptides in the mediation of rodent emotional behaviors, there is currently a lack of information on the effects of central administration of NPY and GAL on fear- and anxiety-related behaviors in mice. In the present study, the effects of intracerebroventricularly administered NPY and GAL were assessed in C57BL/6J mice on a battery of tests for fear- and anxiety-related behavior. NPY (0.5, 1.0 nmol) produced clear anxiolytic-like effects in the elevated plus-maze and light<-->dark exploration test, whereas GAL (0.5, 1.0 nmol) was without effect. NPY (0.5 nmol) also increased locomotor activity in the open field test. In the fear conditioning paradigm, NPY administered prior to training reduced freezing to context (0.5, 1.0 nmol) and auditory cue (1.0 nmol). Pre-training GAL (0.5 nmol) treatment reduced freezing to context. Taken together, results demonstrate robust effects of centrally-administered NPY, but not GAL, on anxiety-like behaviors and fear conditioning in mice. These findings provide a basis for future studies of mice with targeted gene mutations, directed at delineating the anatomical regions and receptor subtypes mediating the effects of NPY and GAL on emotion.

Animals↗
PubMed2005

Gene discovery in neuropharmacological and behavioral studies using Affymetrix microarray data.

We describe methods and software tools for doing data analysis based on Affymetrix microarray data, emphasizing often neglected issues. In our experience with neuroscience studies, experimental design and quality assessment are vital. We also describe in detail the pre-processing methods we have found useful for Affymetrix data. Finally, we summarize the statistical literature and describe some pitfalls in the post-processing analysis.

Animals↗
PubMed2005

Increased attributable risk related to a functional mu-opioid receptor gene polymorphism in association with alcohol dependence in central Sweden.

The mu-opioid receptor (MOR), through its effects on reward and stress-responsivity, modulates alcohol intake in both animal and human laboratory studies. We have previously demonstrated that the frequently occurring A118G single-nucleotide polymorphism (SNP) in exon 1 of the MORgene (OPRM1), which encodes an amino-acid substitution, is functional and receptors encoded by the variant 118G allele bind the endogenous opioid peptide beta-endorphin with three-fold greater affinity than prototype receptors. Other groups subsequently reported that this variant alters stress-responsivity in normal volunteers and also increases the therapeutic response to naltrexone (a mu-preferring opioid antagonist) in the treatment of alcohol dependence. We compared frequencies of genotypes containing an 118G allele in 389 alcohol-dependent individuals and 170 population-based controls without drug or alcohol abuse or dependence. The A118G SNP was present in the Hardy-Weinberg equilibrium with an overall frequency of the 118G allele of 10.9%. There was a significant overall association between genotypes with an 118G allele and alcohol dependence (p=0.0074). The attributable risk for alcohol dependence in subjects with an 118G allele was 11.1%. There was no difference in A118G genotype between type 1 and type 2 alcoholics. In central Sweden, the functional variant 118G allele in exon 1 of OPRM1 is associated with an increased attributable risk for alcohol dependence.

Adult↗
PubMed2005

A novel single nucleotide polymorphism of the neuropeptide Y (NPY) gene associated with alcohol dependence.

BACKGROUND: Neuropeptide Y (NPY) is a major endogenous regulator of anxiety-related behaviors and emotionality. Transgenic work with NPY and null-mutant mice have implicated NPY in the control of alcohol consumption, suggesting that genetic variation of the prepro-NPY gene may also contribute to the heritability of alcoholism. The aim of this study was to examine whether polymorphic variants of the NPY gene are associated with the diagnosis of alcohol dependence. METHODS: We compared allele frequencies of 5 NPY polymorphisms (-883-ins/del, -602, -399, -84, and +1128) in a Nordic population of alcohol-dependent individuals (n = 428 males; n = 149 females) and ethnically matched controls (n = 84 males; n = 93 females) for whom alcohol dependence or any diagnosis of substance disorder was excluded. Patients were further subtyped into type I (late-onset) and type II (early-onset) alcoholics. RESULTS: The -602 marker showed a significant association with alcohol dependence (p = 0.0035; OR, 2.3; 95% CI, 1.3-4.0); a trend level association was further observed for the -399 marker (p = 0.058; OR, 1.3; 95% CI, 0.99-1.7) and the +1128 marker (p = 0.053; OR, 1.8; 95% CI, 0.99-3.1). The association for the -602 marker remained and was strengthened when analyzed in type I subjects only, although this association was not seen in type II patients, and there also was a significant association in the female subjects but not in males. The -602 single nucleotide polymorphism was in strong linkage dysequilibrium (r2 = 0.7; p < 0.0001) with the +1128 single nucleotide polymorphism, which has previously been reported to be associated with a diagnosis of alcoholism. Haplotype-based association confirmed these results. CONCLUSIONS: We report a novel polymorphism at position -602 in the 5' region of the NPY gene that is significantly associated with alcohol dependence. We also describe the haplotype frequencies and linkage dysequilibrium pattern of four variations in that region.

Adolescent↗
PubMed2005

Addiction and its brain science.

AIMS: To illustrate how modern neurobiological approaches will help to identify the neurocircuits and genes involved in addictive behavior. BACKGROUND: The current disorder concept of addiction includes neurobiological foundations and neurobiological research assuming irreversible molecular and structural changes within the brain dopamine reinforcement system, constituting the 'molecular and structural switch' from controlled drug intake to compulsive drug abuse. However, those irreversible changes have not so far been identified and it is suggested that in addition to the mesolimbic dopamine system, other brain systems including the mesocortical and nigrostriatal pathways as well as their non-dopaminergic feedback-loops might be involved in addictive behavior. NEUROBIOLOGICAL APPROACH: A three-step neurobiological approach is described that allows in a first step via novel animal models and imaging techniques to identify the neuroanatomical sites mediating voluntary drug intake, reinstatement of drug-seeking behavior, relapse, loss of control and drug intake despite negative consequences. In a subsequent step, forward genetic approaches including quantitative trait loci (QTL)-analysis and gene expression profiling are helpful in identifying so-called candidate genes. In a final step, conditional animal mutants and selective pharmacological tools are used to functionally validate candidate genes. Following this validation process, the transfer to the human situation has to be made and candidate genes have to be verified further in well-phenotyped cohorts of addicted patients. CONCLUSION: This three-step neurobiological approach, that must involve an interdisciplinary team including experimental psychologists, geneticists, molecular biologists and finally clinical addiction researchers, will allow us to understand where and how the addicted brain goes awry.

Animals↗
PubMed2005

Cannabinoid CB1 receptor antagonism reduces conditioned reinstatement of ethanol-seeking behavior in rats.

The endocannabinoid system is involved in a variety of effects of drugs of misuse, and blockade of the cannabinoid CB1 receptor by selective antagonists elicits marked reductions in opioid and alcohol self-administration. The present study was designed to extend our knowledge of the role of the cannabinoid CB1 receptor in the modulation of alcohol misuse vulnerability in rats. Accordingly, using nonselected Wistar rats and genetically selected Marchigian Sardinian alcohol-preferring (msP) rats, we investigated the effect of the CB1 antagonist SR141716A on operant alcohol self-administration and on reinstatement of alcohol-seeking behavior by environmental conditioning factors. In addition, in situ hybridization studies in both strains were performed to measure cannabinoid CB1 receptor mRNA in different brain areas of these animals. Results showed that intraperitoneal administration of SR141716A (0.03, 1.0 and 3.0 mg/kg) markedly inhibits ethanol self-administration and conditioned reinstatement of ethanol-seeking behavior in both strains of rats. ED50 analysis showed significantly higher sensitivity (P < 0.05) to the effect of SR141716A in msP rats than in heterogeneous Wistar rats. In situ hybridization studies revealed that, compared with Wistar rats, msP animals have consistently greater cannabinoid CB1 receptor mRNA expression in a number of brain areas, including the frontoparietal cortex, caudate-putamen and hippocampus (CA1 and dentate gyrus areas). In conclusion, we provide clear evidence that blockade of CB1 receptors reduces both ethanol self-administration and conditioned reinstatement of alcohol-seeking behavior in rats. In addition, current pharmacological and neuroanatomical data suggest that an altered function of the CB1 receptor system exists between genetically selected alcohol-preferring msP rats and a heterogeneous animal population.

Alcoholism↗
PubMed2005

Unexpectedly high prevalence of alcohol use among pregnant Swedish women: failed detection by antenatal care and simple tools that improve detection.

OBJECTIVE: We examined the use of alcohol during early pregnancy in urban Swedish women, the ability of Swedish antenatal care to identify alcohol-related risk pregnancies and the utility of some potential tools for improving its performance. METHOD: Women attending regular antenatal care were randomized to regular assessment only (control, n = 156) or intensified screening (intervention, n = 147). In the intervention group, alcohol use was determined using the Timeline Followback (TLFB) interview, alcohol use habits with the Alcohol Use Disorder Inventory Test (AUDIT), and biomarkers for alcohol use were analyzed. Data were typically obtained in pregnancy week 12. RESULTS: In the intervention group as a whole, average absolute alcohol consumption during the first 6 weeks of pregnancy was low but highly variable (mean [SD] = 24.9 [50.5] g/week; 4.8 [6.0] episodes for the entire 6 week period); 22 women (15%) drank at levels exceeding 70 g/week during any 2 or more weeks and/or in a heavy episodic drinking pattern, 60 g/episode, on 2 or more episodes. The AUDIT had a moderate sensitivity (54%) to identify these subjects. Biomarkers identified subjects with somatic illness rather than high alcohol consumption. In the control group, only 4 (3%) were identified as using alcohol, indicating a probable underestimation of alcohol use by regular antenatal screening procedures (p = .0001). CONCLUSIONS: An unexpected proportion of pregnant women in urban Sweden consume alcohol at levels likely to produce adverse effects. Regular antenatal care did not identify most of these risk pregnancies. The TLFB identified pregnant women with risk use of alcohol during pregnancy who were only partly identified by analyzing prepregnancy alcohol use patterns with the AUDIT. Elevated laboratory markers likely indicated somatic illness rather than harmful drinking.

Adult↗
PubMed2004

Suppression of ethanol self-administration by the neuropeptide Y (NPY) Y2 receptor antagonist BIIE0246: evidence for sensitization in rats with a history of dependence.

Evidence from genetically modified mice suggests a role for NPY in regulation of ethanol intake, but results of pharmacological studies have been more variable. We have previously shown that potentiation of NPY signaling through antagonism at NPY-Y2 receptors decreases operant responding for ethanol in Wistar rats without a history of dependence. Here, we examined the effects of Y2-antagonism in animals with a history of dependence induced by long-term intermittent exposure to ethanol vapor. The Y2-receptor antagonist BIIE0246 suppressed operant responding for ethanol (approximately 50%, p=0.01), at a dose (0.5 nmol i.c.v.) which was ineffective in subjects without a history of dependence. Responding for the ethanol-free control solution was unaffected. These data confirm that antagonism at central NPY-Y2 receptors selectively suppresses motivation to self-administer ethanol, and indicate that the NPY system is sensitized in animals with a history of dependence. This may render the NPY system, and Y2 receptors in particular, an attractive target for treatment of alcohol dependence.

Alcoholism↗
PubMed2004

Analysis of 5-hydroxytryptamine 2c receptor gene promoter variants as alcohol-dependence risk factors.

AIMS: To examine whether polymorphic variants of the HTR2C gene are associated with diagnosis of alcohol dependence. METHODS: We compared allele frequencies of five HTR2C promoter polymorphisms in a Nordic population of alcohol dependent individuals (Males: n = 309; Females: n = 127) and ethnically matched controls (Males: n = 83; Females: n = 190) in whom alcohol dependence was established, or any diagnosis of substance disorder was excluded, respectively. Patients were further subtyped into Type I (late onset) and Type II (early onset) alcoholics. RESULTS: None of the individual polymorphisms indicated significant association with alcohol dependence. A common promoter haplotype (GAGG) exhibited different distribution frequencies between males and females (Type I), however on Bonferroni's multiple-testing correction, this observation proved to be insignificant. CONCLUSIONS: Although we report a lack of association between alcohol dependence and five common promoter polymorphisms, and the constituted haplotypes, the analysis tends to indicate gender and sub-type differences. We suggest that a follow up study with larger sample numbers should be performed to improve the power to detect the genetic influences of HTR2C in alcohol dependence.

Adolescent↗
PubMed2004

Functional genomics strategies to identify susceptibility genes and treatment targets in alcohol dependence.

Genetic factors contribute to alcohol dependence through two main categories of mechanisms. The 50-60% heritability observed in this disorder is presumably conferred by polymorphic variants, encoding functionally altered proteins, or leading to differential transcriptional activity. Secondly, long term changes during the process of developing dependence are likely encoded by persistent changes in gene expression. Thus, genetic and environmental factors interact at the level of the transcriptome, making this an attractive level of analysis. For this purpose, we have applied differential display and more recently Affymetrix oligonucleotide gene arrays to models of genetic susceptibility and alcohol-induced neuroadaptation.

Adaptation, Physiological↗
PubMed2004

High trait anxiety and hyporeactivity to stress of the dorsomedial prefrontal cortex: a combined phMRI and Fos study in rats.

The neural basis of trait anxiety is poorly understood. In genetically selected hyperanxious (high anxiety-related behavior; HAB) rats, diazepam induces a stronger anxiolytic response than in hypoanxious (low anxiety-related behavior; LAB) rats. A screen for neuronal response differences to diazepam between HAB and LAB rats using pharmacologic fMRI (phMRI) at 7 T revealed a blunted diazepam-induced neuronal deactivation in the dorsomedial prefrontal cortex (dmPFC) of HABs. This was not due to reduced benzodiazepine (BDZ) receptor densities in this region. Instead, dmPFC tissue oxygenation at baseline was found to be significantly lower in HABs. This suggests a tonic relative hypoactivity under the highly stressful phMRI conditions, offering an explanation for the reduced responsivity to the neural depressant effect of diazepam in the sense of a floor effect. Subsequently, Fos immunoreactivity (Fos-IR) showed that ethologically relevant stressors also cause less dmPFC activation in HABs. In the context of an anxiety-inhibiting role of the dmPFC, we propose that failure to sufficiently activate this region in stressful situations may contribute to high trait anxiety.

Animals↗