Alcohol consumption significantly influences the MR signal of frontal choline-containing compounds

Alcohol Craving and Severity are Associated with Dorsal Anterior Cingulate Choline Levels in Individuals with an Alcohol Use Disorder

AIMS

Magnetic resonance spectroscopy (MRS) has been used to probe inflammation in the brain. While altered MRS metabolite levels have previously been found in individuals with alcohol use disorder (AUD), the relationship between potential metabolite markers of inflammation and the clinical correlates of AUD remains understudied. Therefore, this exploratory study sought to elucidate the clinical significance of inflammation in AUD by examining relationships between metabolites, AUD severity, alcohol consumption, and craving in individuals with AUD.

METHODS

Data for this secondary analysis are derived from a two-week clinical trial of ibudilast to treat AUD. Forty-three non-treatment-seeking individuals with an AUD (26M/17F) completed an MRS scan and alcohol-related questionnaires. MRS was performed using a multi-voxel array placed above the corpus callosum, extending from the pregnenual anterior cingulate to premotor cortex. The dorsal anterior cingulate was selected as the volume of interest. Metabolite levels of choline-compounds (Cho), myo-inositol (mI), and creatine+phosphocreatine (Cr) were quantified. Separate hierarchical regression models were used to evaluate the independent effects of metabolite levels on alcohol craving, alcohol problem severity, and alcohol consumption.

RESULTS

Dorsal anterior cingulate Cho predicted alcohol craving and alcohol problem severity over and above demographics, medication, and alcohol consumption measures. mI and Cr did not predict alcohol craving or alcohol problem severity. Metabolite markers were not predictive of alcohol consumption.

CONCLUSIONS

This preliminary study indicates that dACC Cho is sensitive to clinical characteristics of AUD. This is a further step in advancing neurometabolites, particularly Cho, as potential biomarkers and treatment targets for AUD.

Effects of ibudilast on central and peripheral markers of inflammation in alcohol use disorder: A randomized clinical trial

Ibudilast, a neuroimmune modulator, shows promise as a pharmacotherapy for alcohol use disorder (AUD). In vivo administration of ibudilast reduces the expression of pro-inflammatory cytokines in animal models, but its effects on markers of inflammation in humans are unknown. This preliminary study examined the effect of ibudilast on peripheral and potential central markers of inflammation in individuals with AUD. This study also explored the predictive relationship of neurometabolite markers with subsequent drinking in the trial. Non-treatment-seeking individuals with an AUD (n = 52) were randomized to receive oral ibudilast (n = 24) or placebo (n = 28) for 2 weeks. Plasma levels of peripheral inflammatory markers were measured at baseline and after 1 and 2 weeks of medication. At study mid-point, proton magnetic resonance spectroscopy was performed to measure potential neurometabolite markers of inflammation: choline-compounds (Cho), myo-inositol (MI) and creatine + phosphocreatine (Cr) in frontal and cingulate cortices from 43 participants (ibudilast: n = 20; placebo: n = 23). The treatment groups were compared on peripheral and central markers. Ibudilast-treated participants had lower Cho in superior frontal white matter and nominally lower MI in pregenual anterior cingulate cortex. Ibudilast-treated participants had nominally lower C-reactive protein levels at visit 2 and nominally lower TNF-α/IL-10 ratios, relative to placebo. C-reactive protein and Cho levels were correlated, controlling for medication. Superior frontal white matter Cho predicted drinking in the following week. Micro-longitudinal ibudilast treatment may induce peripheral and putative central anti-inflammatory responses in patients with AUD. The neurometabolite responses may be associated with reduction in drinking, suggesting an anti-inflammatory component to the therapeutic action of ibudilast.

Comparison of two magnetic resonance imaging spectroscopy postprocessing methods

OBJECTIVE

The aim of this study was to compare the results obtained using SpectroView® (SV) and J-Magnetic Resonance User Interface (jMRUI) from the same magnetic resonance (MR) spectroscopy of hydrogen data.

METHODS

Data from 23 males with alcohol use disorder (AUD) and 23 healthy non-AUD males were acquired by a 1.5 Tesla MR using a PRESS sequence (TE=30 ms) in four voxels located in the right frontal and left frontal (RF and LF) lobes, and posterior cingulate (AC and PC). The ratio of the signals from both N-acetyl-aspartate (NAA) and choline (Cho) over creatine (Cr) was calculated automatically using SV and semiautomatically by an expert neuroradiologist using jMRUI. The software' agreement was calculated by the 95% limits of agreement (LoA) of the ratio of the obtained values.

RESULTS

The standard deviation was greater in jMRUI than in SV. Although there was a correlation between the results from both methods, it was not possible to predict their variance from one another. Additionally, the 95% LoA showed that jMRUI values were expected to vary from 38 to 190% of those obtained using SV for NAA/Cr in RF of AUD subjects and from 48 to 196% for NAA/Cr in CA of non-AUD individuals.

CONCLUSIONS

The difference between the methods may represent clinically significant magnitudes. We suggest the use of the same method when comparing spectroscopic data. We also suggest that in clinical practice, the automatic method should be preferred.

The neurobiology of wellness: 1H-MRS correlates of agency, flexibility and neuroaffective reserves in healthy young adults

Proton magnetic resonance spectroscopy (¹H-MRS) is a noninvasive imaging technique that measures the concentration of metabolites in defined areas of the human brain in vivo. The underlying structure of natural metabolism-emotion relationships is unknown. Further, there is a wide range of between-person differences in metabolite concentration in healthy individuals, but the significance of this variation for understanding emotion in healthy humans is unclear. Here we investigated the relationship of two emotional constructs, agency and flexibility, with the metabolites glutamate and glutamine (Glx), N-acetylaspartate (tNAA), choline (Cho), creatine (tCr), and myo-inositol (Ins) in the right dorsal anterior cingulate cortex (dACC) in medically and psychiatrically healthy volunteers (N = 20, 9 female; mean age = 22.8 years, SD = 3.40). The dACC was selected because this region is an integrative hub involved in multiple brain networks of emotion, cognition and behavior. Emotional traits were assessed using the Multidimensional Personality Questionnaire Brief Form (MPQ-BF), an empirically derived self-report instrument with an orthogonal factor structure. Phenotypes evaluated were positive and negative agency (MPQ-BF Social Potency, Aggression), emotional and behavioral flexibility (MPQ-BF Absorption, Control-reversed), and positive and negative affect (MPQ-BF Social Closeness; Stress Reaction, Alienation). The resting concentration of tNAA in the dACC was robustly positively correlated with Absorption (r = +0.56, unadjusted p = .005), moderately positively correlated with Social Potency (r = +0.42, unadjusted p = .03), and robustly negatively correlated with Aggression (r = −0.59, unadjusted p = .003). Absorption and Aggression accounted for substantial variance in tNAA (R² = 0.31, 0.35; combined R² = 0.50), and survived correction for multiple comparisons (Holm-Bonferroni adjusted p = .032, 0.021, respectively). dACC Glx and Cho had modest relationships with behavioral flexibility and social affiliation that did not survive this multiple correction, providing effect sizes for future work. Principal Component Analysis (PCA) revealed a three-factor orthogonal solution indicating specific relationships between: 1) Glx and behavioral engagement; 2) Cho and affiliative bonding; and 3) tNAA and a novel dimension that we term neuroaffective reserves. Our results inform the neurobiology of agency and flexibility and lay the groundwork for understanding mechanisms of natural emotion using ¹H-MRS.

Alterations of Metabolites in the Frontal Cortex and Amygdala Are Associated With Cognitive Impairment in Alcohol Dependent Patients With Aggressive Behavior

BACKGROUND

Alcohol dependence (AD) patients have a high prevalence of aggressive behavior (AB). The frontal cortex and amygdala contains various neurotransmitter systems and plays an important role in AB, which is also associated with cognitive deficits. However, to date, no study has addressed the association of metabolites in the frontal cortex and amygdala with cognitive deficits in Chinese aggressive behavior-alcohol dependent patients(AB-ADs).

METHODS

We recruited 80 male AD and 40 male healthy controls (HCs), who completed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), the Modified Overt Aggression Scale (MOAS), and the proton magnetic resonance spectroscopy (¹H MRS) scan using 3.0T Siemens. The ¹H MRS data were automatically fitted with a linear combination model for quantification of metabolite levels of n-acetyl-aspartate (NAA), glutamate (Glu), Choline (Cho) and creatine (Cr). Metabolite levels were reported as ratios to Cr.

RESULTS

The AB-ADs group scored significantly lower than the non-aggression-alcohol dependent patients (NA-ADs) on these two RBANS subscales (immediate memory and attention function indices). The AB-ADs group showed a significant reduction in NAA/CR ratio in the left frontal cortex and Cho/Cr ratio in the left amygdala, and elevation in Glu/Cr ratio in the bilateral amygdala, compared with the NA-ADs group. The NAA/Cr ratio in the left frontal cortex was positively associated with immediate memory (r=0.60, P<0.05), and the Glu/Cr ratio in the right amygdala was negatively associated with delayed memory (r=-0.44,P<0.05) in AB-ADs group.

CONCLUSIONS

Metabolite alterations in the frontal cortex and amygdala may be involved in the pathophysiology of AB in AD and its associated cognitive impairment, especially immediate memory and delayed memory.

Neuroimaging in alcohol use disorder: From mouse to man

This article provides an overview of recent advances in understanding the effects of alcohol use disorders (AUD) on the brain from the perspective of magnetic resonance imaging (MRI) research in preclinical models and clinical studies. As a noninvasive investigational tool permitting assessment of morphological, metabolic, and hemodynamic changes over time, MRI offers insight into the dynamic course of alcoholism beginning with initial exposure through periods of binge drinking and escalation, sobriety, and relapse and has been useful in differential diagnosis of neurological diseases associated with AUD. Structural MRI has revealed acute and chronic effects of alcohol on both white and gray matter volumes. MR Spectroscopy, able to quantify brain metabolites in vivo, has shed light on biochemical alterations associated with alcoholism. Diffusion tensor imaging permits microstructural characterization of white matter fiber tracts. Functional MRI has allowed for elucidation of hemodynamic responses at rest and during task engagement. Positron emission tomography, a non-MRI imaging tool, has led to a deeper understanding of alcohol-induced receptor and neurotransmitter changes during various stages of drinking and abstinence. Together, such in vivo imaging tools have expanded our understanding of the dynamic course of alcoholism including evidence for regional specificity of the effects of AUD, hints at mechanisms underlying the shift from casual to compulsive use of alcohol, and profound recovery with sustained abstinence.

Cerebral Metabolites on the Descending Limb of Acute Alcohol: A Preliminary 1H MRS Study

AIMS

Chronic alcohol use is associated with cerebral metabolite abnormalities, yet alcohol's acute effects on neurometabolism are not well understood. This preliminary study investigated cerebral metabolite changes in vivo on the descending limb of blood alcohol in healthy moderate drinkers.

METHODS

In a pre/post design, participants (N = 13) completed magnetic resonance imaging (MRI) scans prior to and approximately 5 hours after consuming a moderate dose of alcohol (0.60 grams alcohol per kilogram of body weight). Magnetic resonance spectroscopy (1H MRS) was used to quantify cerebral metabolites related to glutamatergic transmission (Glx) and neuroimmune activity (Cho, GSH, myo-inositol) in the thalamus and frontal white matter.

RESULTS

Breath alcohol concentration (BrAC) peaked at 0.070±0.008% (mean ± standard deviation) and averaged 0.025±0.011% directly prior to the descending limb scan. In the thalamus, Glx/Cr and Cho/Cr were significantly elevated on the descending limb scan relative to baseline. BrAC area under the curve, an index of alcohol exposure during the session, was significantly, positively associated with levels of Glx/Cr, Cho/Cr and GSH/Cr in the thalamus. GSH/Cr on the descending limb was inversely correlated with subjective alcohol sedation.

CONCLUSIONS

This study offers preliminary evidence of alcohol-related increases in Glx/Cr, Cho/Cr and GSH/Cr on the descending limb of blood alcohol concentration. Findings add novel information to previous research on neurometabolic changes at peak blood alcohol in healthy individuals and during withdrawal in individuals with alcohol use disorder.

A comparison of hippocampal microglial responses in aged and young rodents following dependent and non-dependent binge drinking

Alcoholism is a highly visible and prevalent issue in the United States. Although binge-drinking is assumed to be a college-age problem, older adults (ages 65+) consume binge amounts of alcohol and have alcohol use disorders (AUDs). Moreover, individuals with alcohol dependence in their youth often continue to drink as they age. As such, this study tested the hypothesis that the effects of alcohol on hippocampal microglia are exacerbated in aged versus younger rodents in two AUD models. Briefly, adult (2-3 months) and aged (15+ months) Sprague-Dawley rats were administered alcohol or control diet using the Majchrowicz model to study alcohol-induced neurodegeneration. To study the effects of non-dependent binge consumption on microglia, adolescent (6-8 weeks) and aged (18+ months) C57/BL6N were subjected to the Drinking in the Dark paradigm. Microglia number and densitometry were assessed using immunohistochemistry. Hippocampal subregional and model/species-specific effects of alcohol were observed, but overall, aging did not appear to increase the alcohol-induced microglia reactivity as measured by Iba-1 densitometry. However, analysis of microglial counts revealed a significant decrease in the number microglia cells in both the alcohol-induced neurodegeneration and DID model across age groups. In the dentate gyrus, the loss of microglia was exacerbated by aging, particularly in mice after DID, non-dependent model. Using qRT-PCR, the persistence of alcohol and aging effects was assessed following the DID model. Allograft Inflammatory Factor 1 mRNA was increased in both young and aged mice by alcohol exposure; however, only in the aged mice did the alcohol effect persist. Overall, these data imply that the microglial response to alcohol is complex with evidence of depressed numbers of microglia but also increased reactivity with advanced age.

Lower Choline Rate in the Left Prefrontal Cortex Is Associated With Higher Amount of Alcohol Use in Alcohol Use Disorder

Excessive and long-term alcohol consumption produce metabolic changes, such as of choline, in many brain regions in alcohol use disorder (AUD) and in non-AUD subjects as well. This study examined the association of choline proportion in the prefrontal cortex with pattern of alcohol use in AUD patients. The choline metabolite was acquired through a single voxel Proton Magnetic Resonance Spectroscopy (¹H MRS). Between-groups comparison corrected by age showed that the ratio of Choline/Creatine (Cho/Cr) was significantly smaller (p = 0.005) in the Left Prefrontal (LPF) of AUD patients when compared to paired non-AUD subjects. A multiple regression analysis corrected by age showed that decreasing ratios of Cho/Cr in the LPF was associated with increasing amount of alcohol consumption in drinks per day (p < 0.01) in AUD patients. Rates of Cho/Cr in the LPF was inversely related to amounts of alcohol consumption possibly indicating the severity of the AUD. Thus, low proportion of Cho/Cr in the LPF could indicate more severe AUD (higher alcohol intake).

Concomitants of alcoholism: differential effects of thiamine deficiency, liver damage, and food deprivation on the rat brain in vivo

RATIONALE

Serious neurological concomitants of alcoholism include Wernicke's encephalopathy (WE), Korsakoff's syndrome (KS), and hepatic encephalopathy (HE).

OBJECTIVES

This study was conducted in animal models to determine neuroradiological signatures associated with liver damage caused by carbon tetrachloride (CCl4), thiamine deficiency caused by pyrithiamine treatment, and nonspecific nutritional deficiency caused by food deprivation.

METHODS

Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) were used to evaluate brains of wild-type Wistar rats at baseline and following treatment.

RESULTS

Similar to observations in ethanol (EtOH) exposure models, thiamine deficiency caused enlargement of the lateral ventricles. Liver damage was not associated with effects on cerebrospinal fluid volumes, whereas food deprivation caused modest enlargement of the cisterns. In contrast to what has repeatedly been shown in EtOH exposure models, in which levels of choline-containing compounds (Cho) measured by MRS are elevated, Cho levels in treated animals in all three experiments (i.e., liver damage, thiamine deficiency, and food deprivation) were lower than those in baseline or controls.

CONCLUSIONS

These results add to the growing body of literature suggesting that MRS-detectable Cho is labile and can depend on a number of variables that are not often considered in human experiments. These results also suggest that reductions in Cho observed in humans with alcohol use disorder (AUD) may well be due to mild manifestations of concomitants of AUD such as liver damage or nutritional deficiencies and not necessarily to alcohol consumption per se.

Brain metabolite levels in recently sober individuals with alcohol use disorder: Relation to drinking variables and relapse

Magnetic resonance spectroscopy (MRS) studies in alcohol use disorder (AUD) typically report lower levels of N-acetylaspartate (NAA) and choline-containing compounds (Cho) in several brain regions. Metabolite levels, however, are labile and can be affected by several competing factors, some related to drinking variables.. This in vivo MRS study included 20 recently sober (19.6±12.6 days) individuals with AUD and 15 controls. MRS was performed in single voxels placed in frontal white matter and thalamic regions using Constant-Time Point Resolved Spectroscopy (CT-PRESS) for absolute quantification of NAA, Cho, total creatine (tCr), and glutamate (Glu). A trend toward a thalamic NAA deficit in the total AUD group compared with controls was attributable to the subgroup of alcoholics who relapsed 3 or so months after scanning. In the total AUD group, frontal and thalamic NAA and Cho levels were lower with more recent drinking; frontal and thalamic Cho levels were also lower in AUD individuals with past stimulant abuse. Thalamic Cho levels were higher in binge-drinking AUD individuals and in those with longer length of alcohol dependence. MRS-visible metabolite peaks appear to be modulated by variables related to drinking behaviors, suggesting a sensitivity of MRS in tracking and predicting the dynamic course of alcoholism.

Increased ventricular cerebrospinal fluid lactate in depressed adolescents

BACKGROUND

Mitochondrial dysfunction has been increasingly examined as a potential pathogenic event in psychiatric disorders, although its role early in the course of major depressive disorder (MDD) is unclear. Therefore, the purpose of this study was to investigate mitochondrial dysfunction in medication-free adolescents with MDD through in vivo measurements of neurometabolites using high-spatial resolution multislice/multivoxel proton magnetic resonance spectroscopy.

METHODS

Twenty-three adolescents with MDD and 29 healthy controls, ages 12-20, were scanned at 3T and concentrations of ventricular cerebrospinal fluid lactate, as well as N-acetyl-aspartate (NAA), total creatine (tCr), and total choline (tCho) in the bilateral caudate, putamen, and thalamus were reported.

RESULTS

Adolescents with MDD exhibited increased ventricular lactate compared to healthy controls [F(1,41)=6.98, P=0.01]. However, there were no group differences in the other neurometabolites. Dimensional analyses in the depressed group showed no relation between any of the neurometabolites and symptomatology, including anhedonia and fatigue.

CONCLUSIONS

Increased ventricular lactate in depressed adolescents suggests mitochondrial dysfunction may be present early in the course of MDD; however it is still not known whether the presence of mitochondrial dysfunction is a trait vulnerability of individuals predisposed to psychopathology or a state feature of the disorder. Therefore, there is a need for larger multimodal studies to clarify these chemical findings in the context of network function.

Glutamatergic and neurometabolic alterations in chronic cocaine users measured with (1) H-magnetic resonance spectroscopy

Cocaine addiction is a chronically relapsing disorder that is associated with harmful consequences. Relapses occur frequently and effective pharmacotherapies are currently sparse. Preclinical studies suggest that altered glutamatergic signaling is crucial for the maintenance of cocaine self-administration. However, the translational validity of these models is currently unknown. Therefore, we investigated potential differences of glutamate, glutamine and further metabolite levels in the pregenual anterior cingulate cortex (pgACC) and the right dorsolateral prefrontal cortex (rDLPFC) of chronic cocaine users and controls using the PRior knOwledge FITting 2.0 tool in combination with two-dimensional J-resolved single-voxel (1) H-magnetic resonance spectroscopy at 3T and voxel tissue composition and relaxation correction. Glutamate and glutamine levels did not differ between cocaine users and controls, but higher weekly cocaine use and higher cocaine hair concentrations were associated with lower glutamine/creatine ratios in the pgACC. Interestingly, cocaine users exhibited higher glucose/total creatine ratios than controls in the pgACC and higher choline/creatine ratios in the pgACC and rDLPFC. These results imply that cocaine use is associated with altered cortical glucose metabolism and membrane turnover. Finally, cocaine use over the past 6 months appears to decrease cortical glutamine levels indicating changes in glutamate cycling.

HIV-1, HCV and alcohol in the CNS: potential interactions and effects on neuroinflammation

Approximately 25% of the HIV-1 positive population is also infected with HCV. The effects of alcohol on HIV-1 or HCV infection have been a research topic of interest due to the high prevalence of alcohol use in these infected patient populations. Although it has long been known that HIV-1 infects the brain, it has only been a little more than a decade since HCV infection of the CNS has been characterized. Both viruses are capable of infecting and replicating in microglia and increasing the expression of proinflammatory cytokines and chemokines, including IL-6 and IL-8. Investigations focusing on the effects of HIV-1, HCV or alcohol on neuroinflammation have demonstrated that these agents are capable of acting through overlapping signaling pathways, including MAPK signaling molecules. In addition, HIV-1, HCV and alcohol have been demonstrated to increase permeability of the blood-brain barrier. Patients infected with either HIV-1 or HCV, or those who use alcohol, exhibit metabolic abnormalities in the CNS that result in altered levels of n-acetyl aspartate, choline and creatine in various regions of the brain. Treatment of HIV/HCV co-infection in alcohol users is complicated by drug-drug interactions, as well as the effects of alcohol on drug metabolism. The drug-drug interactions between the antiretrovirals and the antivirals, as well as the effects of alcohol on drug metabolism, complicate existing models of CNS penetration, making it difficult to assess the efficacy of treatment on CNS infection.

Brain proton magnetic resonance spectroscopy of alcohol use disorders

This chapter critically reviews brain proton magnetic resonance spectroscopy ((1)H MRS) studies performed since 1994 in individuals with alcohol use disorders (AUD). We describe the neurochemicals that can be measured in vivo at the most common magnetic field strengths, summarize our knowledge about their general brain functions, and briefly explain some basic human (1)H MRS methods. Both cross-sectional and longitudinal research of individuals in treatment and of treatment-naïve individuals with AUD are discussed and interpreted on the basis of reported neuropathology. As AUDs are highly comorbid with chronic cigarette smoking and illicit substance abuse, we also summarize reports on their respective influences on regional proton metabolite levels. After reviewing research on neurobiologic correlates of relapse and genetic influences on brain metabolite levels, we finish with suggestions on future directions for (1)H MRS studies in AUDs. The review demonstrates that brain metabolic alterations associated with AUDs as well as their cognitive correlates are not simply a consequence of chronic alcohol consumption. Future MR research of AUDs in general has to be better prepared - and supported - to study clinically complex relationships between personality characteristics, comorbidities, neurogenetics, lifestyle, and living environment, as all these factors critically affect an individual's neurometabolic profile. (1)H MRS is uniquely positioned to tackle these complexities by contributing to a comprehensive biopsychosocial profile of individuals with AUD: it can provide non-invasive biochemical information on select regions of the brain at comparatively low overall cost for the ultimate purpose of informing more efficient treatments of AUDs.

Neuroimmune basis of alcoholic brain damage

Alcohol-induced brain damage likely contributes to the dysfunctional poor decisions associated with alcohol dependence. Human alcoholics have a global loss of brain volume that is most severe in the frontal cortex. Neuroimmune gene induction by binge drinking increases neurodegeneration through increased oxidative stress, particularly NADPH oxidase-induced oxidative stress. In addition, HMGB1-TLR4 and innate immune NF-κB target genes are increased leading to persistent and sensitized neuroimmune responses to ethanol and other agents that release HMGB1 or directly stimulate TLR receptors and/or NMDA receptors. Neuroimmune signaling and glutamate excitotoxicity are linked to alcoholic neurodegeneration. Models of adolescent alcohol abuse lead to significant frontal cortical degeneration and show the most severe loss of hippocampal neurogenesis. Adolescence is a period of high risk for ethanol-induced neurodegeneration and alterations in brain structure, gene expression, and maturation of adult phenotypes. Together, these findings support the hypothesis that adolescence is a period of risk for persistent and long-lasting increases in brain neuroimmune gene expression that promote persistent and long-term increases in alcohol consumption, neuroimmune gene induction, and neurodegeneration that we find associated with alcohol use disorders.

The influence of the menstrual cycle on the result of brain examination with hydrogen magnetic resonance spectroscopy - a pilot study

BACKGROUND AND PURPOSE

Hydrogen magnetic resonance spectroscopy (1HMRS) is nowadays one of the basic tools for noninvasive brain metabolism assessment. The study focuses on the important problem of the influence of hormone fluctuation during the menstrual cycle on brain metabolism, assessed by 1HMRS for clinical diagnostics.

MATERIAL AND METHODS

In 11 healthy regularly menstruating women, 1HMRS was performed at the start (phase I), in the middle (phase II) and at the end (phase III) of the menstrual cycle. The relative concentration ratios of 12 brain metabolites in every woman in all cycle phases were examined, in 6 different volumes of interest (VOIs). Finally, statistically significant differences in relative metabolite ratios between the phases examined in given locations were sought.

RESULTS

Statistically significant relations between menstrual cycle phases and relative ratios of 4 metabolites - Lac/Cr, NAA/Cr, Glx1/Cr and Glx2/Cr - in different brain locations were found. In all locations, mean NAA/Cr ratios were greater in phase I compared to the other phases. A similar relationship was found for Glx1/Cr ratio in one location (left occipital lobe). For Lac/Cr and Glx2/Cr ratios, a higher mean ratio value was obtained in phase II compared to phases I and III in the right occipital lobe and left basal ganglia, respectively.

CONCLUSIONS

Menstrual cycle phase should be considered in planning a date and interpretation of 1HMRS examination, performed for the verification of a disease manifesting as brain metabolite disturbances in the 1HMRS spectrum.

Loss of control of alcohol use and severity of alcohol dependence in non-treatment-seeking heavy drinkers are related to lower glutamate in frontal white matter

BACKGROUND

The development and maintenance of alcohol use disorders (AUD) have been hypothesized to be associated with an imbalance of glutamate (GLU) homeostasis. White matter (WM) loss, especially in anterior brain regions, has been reported in alcohol dependence, which may involve disturbances in both myelin and axonal integrity. Frontal lobe dysfunction plays an important role in addiction, because it is suggested to be associated with the loss of control over substance use. This study investigated magnetic resonance spectroscopy (MRS)-detectable Glu levels in frontal WM of non-treatment-seeking heavy drinkers and its associations with AUD symptoms.

METHODS

Single-voxel MR spectra optimized for Glu assessment (TE 80 ms) were acquired at 3T from a frontal WM voxel in a group of heavy drinking, non-treatment-seeking subjects in comparison with a group of subjects with only light alcohol consumption.

RESULTS

The results corroborate previous findings of increased total choline in heavy drinking subjects. A negative association of Glu levels with severity of alcohol dependence and especially loss of control over time and amount of alcohol intake was observed.

CONCLUSIONS

In contrast to the rather unspecific rise in choline-containing compounds, low Glu in frontal WM may be specific for the shift from nondependent heavy drinking to dependence and does not reflect a simple effect of the amount of alcohol consumption alone.

Neurometabolite concentration and clinical features of chronic alcohol use: a proton magnetic resonance spectroscopy study

Chronic, heavy alcohol consumption may affect the concentration of neurometabolites assessed with proton magnetic resonance spectroscopy ((1)H-MRS). We investigated the largest sample reported to date (N=213) with the primary goal of determining how specific clinical features impact neurometabolite concentrations in an anterior cingulate gray matter voxel. This community-dwelling sample included both treatment-seeking and non-treatment-seeking individuals. A healthy control group (N=66) was matched for age and education. In multivariate analyses predicting neurometabolite concentrations, the heavy drinking group had greater concentrations overall. An age by group interaction was noted, as group difference across neurometabolites increased with age. More years drinking, but not more drinks per drinking day (DPDD), predicted greater concentrations of choline-containing compounds (Cho), creatine-phosphocreatine (Cre), glutamate-glutamine (Glx), and N-acetyl-aspartate (NAA). The effects of other clinical variables (depression, cigarette smoking, marijuana use) were negligible. After controlling for DPDD and years drinking, treatment-seeking status had no impact on neurometabolites. In the very oldest portion of the sample (mean age=50), however, a negative relationship was seen between NAA and years drinking. These results suggest that the nature of neurometabolite abnormalities in chronic heavy drinkers may vary as a function of duration of abuse.

Quantitative assessment of neurochemical changes in a rat model of long-term alcohol consumption as detected by in vivo and ex vivo proton nuclear magnetic resonance spectroscopy

The aim of present study was to quantitatively investigate the neurochemical profile of the frontal cortex region in a rat model of long-term alcohol consumption, by using in vivo proton magnetic resonance spectroscopy ((1)H-MRS) at 4.7 T and ex vivo(1)H high-resolution magic angle spinning (HR-MAS) technique at 11.7 T. Twenty male rats were divided into two groups and fed a liquid diet for 10 weeks. After 10 weeks, in vivo(1)H MRS spectra were acquired from the frontal cortex brain region. After in vivo(1)H MRS experiments, all animals were sacrificed and 20 frontal cortex tissue samples were harvested. All tissue examinations were performed with the 11.7 T HR-MAS spectrometer and high-resolution spectra were acquired. The in vivo and ex vivo spectra were quantified as absolute metabolite concentrations and normalized ratios of total signal-intensity (i.e., metabolitesNorm), respectively. The absolute quantifications of in vivo spectra showed significantly higher glycerophosphocholine plus phosphocholine (GPC+PCh) and lower myo-inositol (mIns) concentrations in ethanol-treated rats compared to controls. The quantifications of ex vivo spectra showed significantly higher PChNorm, ChoNorm and tChoNorm, and lower GPCNorm and mInsNorm ratio levels in ethanol-treated rats compared to controls. Our findings suggest that reduced mIns concentrations caused by the long-term alcohol consumption may lead to hypo-osmolarity syndrome and astrocyte hyponatremia. In addition, increased choline-containing compound concentrations may reflect an increased cell turnover rate of phosphatidylcholine and other phospholipids, indicating an adaptive mechanism. Therefore, these results might be utilized as key markers in chronic alcohol intoxication metabolism.

Preclinical (1)H-MRS neurochemical profiling in neurological and psychiatric disorders

The ongoing development of animal models of neurological and psychiatric disorders in combination with the development of advanced nuclear magnetic resonance (NMR) techniques and instrumentation has led to increased use of in vivo proton NMR spectroscopy ((1)H-MRS) for neurochemical analyses. (1)H-MRS is one of only a few analytical methods that can assay in vivo and longitudinal neurochemical changes associated with neurological and psychiatric diseases, with the added advantage of being a technique that can be utilized in both preclinical and clinical studies. In this review, recent progress in the use of (1)H-MRS to investigate animal models of neurological and psychiatric disorders is summarized with examples from the literature and our own work.

MR spectroscopy in opiate maintenance therapy: association of glutamate with the number of previous withdrawals in the anterior cingulate cortex

Pre-clinical research indicates that opioids reduce extracellular glutamate in acute opioid treatment, whereas during withdrawal, glutamatergic neurotransmission is increased and withdrawal symptoms can be blocked by glutamate receptor antagonists. The glutamate hypothesis of addiction suggests that withdrawal-associated hyperglutamatergic states destabilize the glutamatergic system chronically and contribute to relapse. magnetic resonance spectroscopy at three tesla optimized for glutamate assessment (TE 80 ms) was performed in the anterior cingulate gyrus (ACC) and frontal white matter (fWM) of 17 opiate-dependent patients during opiate maintenance therapy and 20 healthy controls. Controlling for age and gray matter content, glutamate in the ACC was positively associated with the number of previous withdrawals. For glutamate + glutamine (Glx), a significant group-age interaction was found. Whereas Glx declines with age in healthy controls, Glx increases with age in opiate-dependent patients. The number of previous withdrawals did not correlate with age. In fWM spectra, increased Cho concentrations were observed in opiate-dependent patients. Both new findings, the positive correlation of glutamate and previous withdrawals and increasing Glx with age in contrast to an age-dependent Glx decrease in controls indicate a destabilization of the glutamate system in opiate-dependent patients and support the glutamate hypothesis of addiction. Increased Cho concentrations in fWM corroborate findings of WM abnormalities in opioid-dependent subjects.

Intravenous ethanol infusion decreases human cortical γ-aminobutyric acid and N-acetylaspartate as measured with proton magnetic resonance spectroscopy at 4 tesla

BACKGROUND

Ethanol modulates glutamate and γ-aminobutyric (GABA) function. However, little is known about the acute pharmacologic effects of ethanol on levels of GABA, glutamate, and other metabolites measurable in the human cortex in vivo with proton magnetic resonance spectroscopy ((1)H-MRS).

METHODS

Eleven healthy social drinkers received two intravenous ethanol infusions that raised breath alcohol levels to a clamped plateau of 60 mg/dL over 60-70 min. The first infusion established tolerability of the procedure, and the second procedure, conducted 15 ± 12 days later, was performed during (1)H-MRS of occipital GABA, glutamate, and other metabolites.

RESULTS

The time course of brain ethanol approximated that of breath ethanol, but venous ethanol lagged by approximately 7 min. The GABA fell 13 ± 8% after 5 min of the ethanol infusion and remained reduced (p = .003) throughout the measurement. The combination of N-acetylaspartate and N-acetylaspartyl glutamate (summed as NAA) fell steadily during the infusion by 8 ± 3% (p = .0036).

CONCLUSIONS

Ethanol reduced cortical GABA and NAA levels in humans. Reductions in GABA levels are consistent with facilitation of GABA(A) receptor function by ethanol. The gradual decline in NAA levels suggests inhibition of neural or metabolic activity in the brain.

Molecular and behavioral aspects of the actions of alcohol on the adult and developing brain

The brain is one of the major target organs of alcohol actions. Alcohol abuse can lead to alterations in brain structure and functions and, in some cases, to neurodegeneration. Cognitive deficits and alcohol dependence are highly damaging consequences of alcohol abuse. Clinical and experimental studies have demonstrated that the developing brain is particularly vulnerable to alcohol, and that drinking during gestation can lead to a range of physical, learning and behavioral defects (fetal alcohol spectrum disorders), with the most dramatic presentation corresponding to fetal alcohol syndrome. Recent findings also indicate that adolescence is a stage of brain maturation and that heavy drinking at this stage can have a negative impact on brain structure and functions causing important short- and long-term cognitive and behavioral consequences. The effects of alcohol on the brain are not uniform; some brain areas or cell populations are more vulnerable than others. The prefrontal cortex, the hippocampus, the cerebellum, the white matter and glial cells are particularly susceptible to the effects of ethanol. The molecular actions of alcohol on the brain are complex and involve numerous mechanisms and signaling pathways. Some of the mechanisms involved are common for the adult brain and for the developing brain, while others depend on the developmental stage. During brain ontogeny, alcohol causes irreversible alterations to the brain structure. It also impairs several molecular, neurochemical and cellular events taking place during normal brain development, including alterations in both gene expression regulation and the molecules involved in cell-cell interactions, interference with the mitogenic and growth factor response, enhancement of free radical formation and derangements of glial cell functions. However, in both adult and adolescent brains, alcohol damages specific brain areas through mechanisms involving excitotoxicity, free radical formation and neuroinflammatory damage resulting from activation of the innate immune system mediated by TLR4 receptors. Alcohol also acts on specific membrane proteins, such as neurotransmitter receptors (e.g. NMDA, GABA-A), ion channels (e.g. L-type Ca²⁺ channels, GIRKs), and signaling pathways (e.g. PKA and PKC signaling). These effects might underlie the wide variety of behavioral effects induced by ethanol drinking. The neuroadaptive changes affecting neurotransmission systems which are more sensitive to the acute effects of alcohol occur after long-term alcohol consumption. Alcohol-induced maladaptations in the dopaminergic mesolimbic system, abnormal plastic changes in the reward-related brain areas and genetic and epigenetic factors may all contribute to alcohol reinforcement and alcohol addiction. This manuscript reviews the mechanisms by which ethanol impacts the adult and the developing brain, and causes both neural impairments and cognitive and behavioral dysfunctions. The identification and the understanding of the cellular and molecular mechanisms involved in ethanol toxicity might contribute to the development of treatments and/or therapeutic agents that could reduce or eliminate the deleterious effects of alcohol on the brain.

Measurement of serum, liver, and brain cytokine induction, thiamine levels, and hepatopathology in rats exposed to a 4-day alcohol binge protocol

BACKGROUND

 In rodent and human studies, ethanol (EtOH) exposure is associated with elevated brain levels of the magnetic resonance spectroscopy (MRS) signal representing choline-containing compounds (Cho). One interpretation of elevated brain Cho is that it is a marker of neuroinflammation, and some evidence suggests that EtOH exposure promotes neuroinflammation. This study aimed to determine whether binge EtOH exposure (intragastric 3 g/kg 25% EtOH every 8 hours for 4 days) would induce the expression of certain cytokines in blood, liver, or brain, thereby supporting the neuroinflammation hypothesis of elevated Cho.

METHODS

Ten of 18 wild-type male Wistar rats (~322 g at baseline) were exposed to EtOH and attained average blood alcohol levels of ~315 mg/dl across 4 days. Blood for cytokine immunoassays was collected at baseline, after 5 doses of EtOH (binge), and immediately preceding euthanasia either 4 or 24 hours after the last dose of EtOH. Blood was additionally assayed for the levels of thiamine and liver enzymes; liver histopathology was performed postmortem; and tissue from liver and 6 brain regions was assayed for the potential induction of 7 cytokines.

RESULTS

There were no group effects on the levels of thiamine or its phosphate derivatives, thiamine monophosphate or thiamine diphosphate. ANOVAs of liver enzyme levels indicated that only alkaline phosphatase (ALP) levels were higher in the EtOH group than in control group at binge; ALP elevations, however, are difficult to explain in the absence of changes in the levels of additional liver enzymes. Postmortem liver pathology provided evidence for minimal microvesicular lipidosis and portocentric fibrosis in the EtOH group. Group effects on the levels of the measured cytokines in the blood (TNF-α, IFN-γ, IL-1β, IL-4, IL-5, IL-13, and GRO/CXCL1) were not significant. Similarly, postmortem evaluation of liver cytokines did not reveal group effects. Postmortem evaluation of the 7 cytokines in 6 brain regions (anterior cerebellar vermis, cingulate cortex, frontal cortex, hippocampus, hypothalamus, striatum) also failed to identify group effects.

CONCLUSIONS

A single 4-day bout of binge EtOH exposure alone was insufficient to induce the expression of 7 cytokines in blood, liver, or 6 brain regions of wild-type Wistar rats. Alternative interpretations for elevations in brain Cho in response to a 4-day binge EtOH treatment are therefore necessary and may include induction of cytokines not measured herein or other noninflammatory mechanisms.

Addiction research centres and the nurturing of creativity department of addictive behaviour and addiction medicine, central institute of Mental Health, Mannheim, University of Heidelberg

Addictive behaviour is as prevalent in Germany as in other western countries, but in contrast to some European countries and the United States, very little money was given to this research field. Change came in the early 1990s, when the German government started to launch specific grants for addiction research. The first chair in addiction research was created in 1999 (Karl Mann) at the Central Institute of Mental Health Mannheim (CIMH; University of Heidelberg). The recruitment of a pre-clinical alcohol researcher as head of the department of psychopharmacology followed (Rainer Spanagel). This 'addiction research cluster' collaborates with several research groups at the CIMH (such as genetics). We inaugurated a clinical trial network which now comprises up to 20 treatment centres throughout Germany. Like most authors, we found effect sizes of different treatment modalities more in the low to moderate range, perhaps because of the heterogeneity of large patient samples. Therefore, we concentrated upon the biological basis of addiction in order to define more homogeneous 'subtypes' of patients for a better match with existing treatments. Results concerning genetics and neuroimaging (both animal and human) are promising, and could move our field towards a more personalized treatment approach. Our funding has been extended over the years, including involvement in several large European grants. We are studying substance-related problems as well as so-called 'behavioural addictions'. As a natural consequence of this development, we are deeply involved both in informing the general public on addiction issues as well as in counselling policy makers in Germany.

Brain injury and recovery following binge ethanol: evidence from in vivo magnetic resonance spectroscopy

BACKGROUND

The binge-drinking model in rodents using intragastric injections of ethanol (EtOH) for 4 days results in argyrophilic corticolimbic tissue classically interpreted as indicating irreversible neuronal degeneration. However, recent findings suggest that acquired argyrophilia can also identify injured neurons that have the potential to recover. The current in vivo magnetic resonance (MR) imaging and spectroscopy study was conducted to test the hypothesis that binge EtOH exposure would injure but not cause the death of neurons as previously ascertained postmortem.

METHODS

After baseline MR scanning, 11 of 19 rats received a loading dose of 5 g/kg EtOH via oral gavage, then a maximum of 3 g/kg every 8 hours for 4 days, for a total average cumulative EtOH dose of 43 +/- 1.2 g/kg and average blood alcohol levels of 258 +/- 12 mg/dL. All animals were scanned after 4 days of gavage (post-gavage scan) with EtOH (EtOH group) or dextrose (control [Con] group) and again after 7 days of abstinence from EtOH (recovery scan).

RESULTS

Tissue shrinkage at the post-gavage scan was reflected by significantly increased lateral ventricular volume in the EtOH group compared with the Con group. At the post-gavage scan, the EtOH group had lower dorsal hippocampal N-acetylaspartate and total creatine and higher choline-containing compounds than the Con group. At the recovery scan, neither ventricular volume nor metabolite levels differentiated the groups.

CONCLUSIONS

Rapid recovery of ventricular volume and metabolite levels with removal of the causative agent argues for transient rather than permanent effects of a single EtOH binge episode in rats.

Increased activation of the ACC during a spatial working memory task in alcohol-dependence versus heavy social drinking

BACKGROUND

Activation of the anterior cingulate cortex (ACC) in a spatial working memory task has been associated with risk factors for alcohol use disorders such as low alcohol effects and positive alcohol expectations in adolescents. To transfer these results into adults, we used the same task in adults.

METHODS

During functional magnetic resonance imaging, 12 light social, 7 heavy social, and 11 non-abstinent-dependent alcohol drinkers performed a spatial working memory task and completed measures of automatic alcohol-related thoughts and behavior (Obsessive-Compulsive Drinking Scale-OCDS), alcohol use of the last 90 days, and general intelligence.

RESULTS

Behavioral performance in the spatial working memory task was not significantly different in all 3 groups. Controlling for differences in general intelligence alcohol-dependent participants showed a higher task-related activation of the dorsal ACC (dACC) in comparison with light and heavy social drinkers. Measures of the OCDS were positively correlated with the activation in the left hippocampus and right thalamus in all participants.

CONCLUSIONS

Our results support the findings of increased dACC activation during a spatial working memory task as a risk factor for alcohol dependence. Increased task-related activation in the dACC was only observed in alcohol-dependent participants and not in heavy social drinkers with comparable alcohol consumption. Furthermore, the absence of behavioral performance differences between groups as well as an association between dACC activation and working memory performance indicates subtle working memory deficits. Low capacity of working memory has been linked to more automatic and less self-regulated behavior in studies on natural reward processing. Therefore, additional neural activation during performance of the non-alcohol-related working memory task in participants with higher OCDS values in the left hippocampus and the right thalamus may be a consequence of decreased neural capacity because of distracting alcohol-related thoughts.

Brain involvement in rheumatoid arthritis: a magnetic resonance spectroscopy study

OBJECTIVE

Tumor necrosis factor alpha was recently implicated as an important mediator of communication between the peripheral and cerebral immune systems in an animal model of chronic inflammation. The purpose of this study was to examine by proton magnetic resonance spectroscopy ((1)H-MRS) the influence of inflammation on cerebral metabolism in patients with rheumatoid arthritis (RA).

METHODS

Single-voxel (1)H-MRS of the centrum semiovale was performed on 35 RA patients (6 men and 29 women; mean +/- SD age 51.8 +/- 14.6 years) and 28 healthy age- and sex-matched control subjects (9 men and 19 women; mean +/- SD age 50.2 +/- 10.4 years). None of the study subjects had any neurologic signs or symptoms. Clinical markers of disease activity were correlated with the (1)H-MRS findings.

RESULTS

Patients with active RA, as reflected by an elevated erythrocyte sedimentation rate (ESR), had a significantly higher ratio of choline to creatine and a significantly lower ratio of N-acetylaspartate to choline than did patients with inactive RA, as reflected by a normal ESR. Moreover, the ratios of choline to creatine and NAA to choline were significantly correlated with the ESR after correction for age, sex, smoking status, handedness, alcohol consumption, medication use, and disease duration. Medication use had no additional effect on these associations.

CONCLUSION

Our data show that systemic inflammation in RA is associated with metabolic changes in the brain.

In vivo evidence for alcohol-induced neurochemical changes in rat brain without protracted withdrawal, pronounced thiamine deficiency, or severe liver damage

Magnetic resonance spectroscopy (MRS) studies in human alcoholics report decreases in N-acetylaspartate (NAA) and choline-containing (Cho) compounds. Whether alterations in brain metabolite levels are attributable to alcohol per se or to physiological effects of protracted withdrawal or impaired nutritional or liver status remains unclear. Longitudinal effects of alcohol on brain metabolites measured in basal ganglia with single-voxel MRS were investigated in sibling pairs of wild-type Wistar rats, with one rat per pair exposed to escalating doses of vaporized alcohol, the other to vapor chamber air. MRS was conducted before alcohol exposure and twice during exposure. After 16 weeks of alcohol exposure, rats achieved average blood alcohol levels (BALs) of approximately 293 mg per 100 ml and had higher Cho and a trend for higher glutamine+glutamate (Glx) than controls. After 24 weeks of alcohol exposure, BALs rose to approximately 445 mg per 100 ml, and alcohol-exposed rats had higher Cho, Glx, and glutamate than controls. Thiamine and thiamine monophosphate levels were significantly lower in the alcohol than the control group but did not reach levels low enough to be considered clinically relevant. Histologically, livers of alcohol-exposed rats exhibited greater steatosis and lower glycogenosis than controls, but were not cirrhotic. This study demonstrates a specific pattern of neurobiochemical changes suggesting excessive membrane turnover or inflammation, indicated by high Cho, and alterations to glutamate homeostasis in the rat brain in response to extended vaporized alcohol exposure. Thus, we provide novel in vivo evidence for alcohol exposure as causing changes in brain chemistry in the absence of protracted withdrawal, pronounced thiamine deficiency, or severe liver damage.

Alcoholism: A Systems Approach From Molecular Physiology to Addictive Behavior

Alcohol consumption is an integral part of daily life in many societies. The benefits associated with the production, sale, and use of alcoholic beverages come at an enormous cost to these societies. The World Health Organization ranks alcohol as one of the primary causes of the global burden of disease in industrialized countries. Alcohol-related diseases, especially alcoholism, are the result of cumulative responses to alcohol exposure, the genetic make-up of an individual, and the environmental perturbations over time. This complex gene × environment interaction, which has to be seen in a life-span perspective, leads to a large heterogeneity among alcohol-dependent patients, in terms of both the symptom dimensions and the severity of this disorder. Therefore, a reductionistic approach is not very practical if a better understanding of the pathological processes leading to an addictive behavior is to be achieved. Instead, a systems-oriented perspective in which the interactions and dynamics of all endogenous and environmental factors involved are centrally integrated, will lead to further progress in alcohol research. This review adheres to a systems biology perspective such that the interaction of alcohol with primary and secondary targets within the brain is described in relation to the behavioral consequences. As a result of the interaction of alcohol with these targets, alterations in gene expression and synaptic plasticity take place that lead to long-lasting alteration in neuronal network activity. As a subsequent consequence, alcohol-seeking responses ensue that can finally lead via complex environmental interactions to an addictive behavior.

Mechanisms of neurodegeneration and regeneration in alcoholism

AIMS

This is a review of preclinical studies covering alcohol-induced brain neuronal death and loss of neurogenesis as well as abstinence-induced brain cell genesis, e.g. brain regeneration. Efforts are made to relate preclinical studies to human studies.

METHODS

The studies described are preclinical rat experiments using a 4-day binge ethanol treatment known to induce physical dependence to ethanol. Neurodegeneration and cognitive deficits following binge treatment mimic the mild degeneration and cognitive deficits found in humans. Various histological methods are used to follow brain regional degeneration and regeneration.

RESULTS

Alcohol-induced degeneration occurs due to neuronal death during alcohol intoxication. Neuronal death is related to increases in oxidative stress in brain that coincide with the induction of proinflammatory cytokines and oxidative enzymes that insult brain. Degeneration is associated with increased NF-kappaB proinflammatory transcription and decreased CREB transcription. Corticolimbic brain regions are most sensitive to binge-induced degeneration and induce relearning deficits. Drugs that block oxidative stress and NF-kappaB transcription or increase CREB transcription block binge-induced neurodegeneration, inhibition of neurogenesis and proinflammatory enzyme induction. Regeneration of brain occurs during abstinence following binge ethanol treatment. Bursts of proliferating cells occur across multiple brain regions, with many new microglia across brain after months of abstinence and many new neurons in neurogenic hippocampal dentate gyrus. Brain regeneration may be important to sustain abstinence in humans.

CONCLUSIONS

Alcohol-induced neurodegeneration occurs primarily during intoxication and is related to increased oxidative stress and proinflammatory proteins that are neurotoxic. Abstinence after binge ethanol intoxication results in brain cell genesis that could contribute to the return of brain function and structure found in abstinent humans.

Biochemical changes in the cingulum in patients with schizophrenia and chronic bipolar disorder

Biochemical changes have been reported in vivo in the brain in schizophrenia patients using 1H-magnetic resonance spectroscopy (MRS). The aim of this study was to assess the specificity of biochemical changes occurring in schizophrenia patients, in a direct comparison with bipolar disorder patients. Fourteen patients with chronic paranoid schizophrenia, 17 euthymic type I bipolar patients with no previous history of psychotic symptoms and 15 healthy controls were included, most of them were female. They underwent a study with MRS: proton spectra were acquired using a Signa 1.5 T CVI scanner, with a localised single voxel PRESS sequence. N-acetyl aspartate (NAA), Creatine (Cr), and Choline (Cho) metabolite resonance intensities were all quantified in the cingulum, a region of interest in schizophrenia and bipolar disorder. Schizophrenia patients showed a significantly higher Cho/Cre as well as lower NAA/Cho ratios as compared with controls and bipolar patients. No significant differences were found among the three groups as regards NAA/Cre levels. These data are consistent with an increase in the concentration of choline in the cingulum in chronic schizophrenia, at least in this predominantly female group. Such an increase seems to be more intense than in psychosis-free bipolar disorder patients.

Effects of age and sex on brain glutamate and other metabolites

We previously reported the effects of sex and age on brain glutamate, as well as other brain metabolite concentrations, measured with a new technique called TE-averaged PRESS on a 3-T Siemens scanner in four brain regions of 50 healthy subjects. While revising the original IDL processing script for a scanner upgrade, we noted a programming error in the original code that did not use the unsuppressed water signal corrected for T2 decay and percentage of cerebrospinal fluid to calculate the metabolite concentrations. We report here the reanalyzed metabolite concentrations of glutamate and other metabolites that differ from our original article, based on measurements performed on the original 50 as well as the 12 new subjects (total 62 healthy subjects: 39 males and 23 females). Our reanalyzed data no longer show sex differences in brain glutamate levels in four brain regions measured, but we continue to observe significant age-related declines in glutamate, especially in the parietal gray matter and basal ganglia, and to a lesser degree in the frontal white matter. Further analyses confirm that the basal ganglia and frontal white matter glutamate declines were predominantly due to a decline in men, but not women. These findings indicate that brain glutamate concentrations decline markedly with age, and may be especially useful as a marker for brain diseases that are affected by aging.

Are treated alcoholics representative of the entire population with alcohol use disorders? A magnetic resonance study of brain injury

Almost all we know about neurobiological brain injury in alcohol use disorders has been derived from convenience samples of treated alcoholics. Recent research has demonstrated more comorbid conditions, poorer psychosocial functioning, and higher dependence levels in treated alcoholics than in their treatment-naive counterparts. Thus, it is not clear whether neuroimaging results from convenience samples of treated alcoholics can be generalized to the entire population with alcohol use disorders. We compared 35 treated alcoholics at 1 week of abstinence (ALC) and 32 treatment-naive heavy drinkers (HD) on regional brain volumes and metabolite concentrations obtained by in vivo magnetic resonance at 1.5 Tesla to evaluate for potential group differences. Then, we evaluated whether comorbid cigarette smoking and common demographic and clinical variables mediated any existing neurobiological group differences. ALC demonstrated smaller lobar gray matter volumes and thalami than HD, exacerbated by chronic smoking. Furthermore, concentrations of N-acetyl-aspartate (an accepted marker of neuronal viability), choline-containing metabolites (involved in membrane turnover), and myo-inositol (a putative marker of glial cells and osmolyte) were lower in multiple brain regions of ALC compared to HD. The lower N-acetyl-aspartate concentrations in white matter of ALC versus HD were explained by average number of drinks per month over the year preceding study. However, the other group differences were not explained by common drinking, demographic, and clinical variables (used as covariates at the same time) or by excluding participants with comorbid mood disorders. Taken together, this suggests that the degree of brain atrophy, as well as neuronal and membrane injury in clinical samples of alcoholics cannot be generalized to the much larger population with alcohol use disorders that does not seek treatment.