Changes in the brain directly following alcohol consumption-a study of healthy male individuals, with the use of proton magnetic resonance spectroscopy (1HMRS) and diffusion (DWI)

AIMS

To use proton magnetic resonance spectroscopy (1HMRS) and diffusion weighted imaging (DWI) to identify ethanol in the brain directly after consumption, and examine changes in brain metabolite levels and brain microstructure relative to the duration of time following exposure to alcohol.

METHODS

The study involved 44 male volunteers (18-55 years). All brain changes were assessed in the frontal lobes, occipital lobes, basal ganglia and cerebellum, however the detailed analyses focused on the frontal lobes. All participants were examined four times, i.e. before and 0.5-hour, 1 hour and 2 hours after consumption of 150 mL pure vodka (60 g of ethanol).

RESULTS

The highest ethanol levels were identified between 0.5 and 1 hour following alcohol intake. There were significant increases in the concentrations of lipids and lactates approximately one hour after alcohol consumption, and the concentration levels were found to normalise during the following two hours. Some statistically insignificant trends of changes were found for tCr, tCho, mI, GABA, Glc, Glx and tNAA. For the DWI and ADC (Apparent Diffusion Coefficient of water) values, the findings showed statistically insignificant decrease and increase, followed by a tendency towards normalisation. Similar associations in changes of metabolite concentrations and DWI and ADC values were found in the other locations investigated in the study.

CONCLUSION

A single dose of alcohol as used in this experiment produces increases in lipids and lactates in brain tissues that appear reversible.

Cerebral bioenergetic differences measured by phosphorus-31 magnetic resonance spectroscopy between bipolar disorder and healthy subjects living in two different regions suggesting possible effects of altitude

AIM

Increased oxidative stress in cerebral mitochondria may follow exposure to the systemic hypobaric hypoxia associated with residing at higher altitudes. Because mitochondrial dysfunction is implicated in bipolar disorder (BD) pathophysiology, this may impact the cerebral bioenergetics in BD. In this study, we evaluated the cerebral bioenergetics of BD and healthy control (HC) subjects at two sites, located at sea level and at moderate altitude.

METHODS

Forty-three veterans with BD and 33 HC veterans were recruited in Boston (n = 22) and Salt Lake City (SLC; n = 54). Levels of phosphocreatine, β nucleoside triphosphate (βNTP), inorganic phosphate, and pH over total phosphate (TP) were measured using phosphorus-31 magnetic resonance spectroscopy in the following brain regions: anterior cingulate cortex and posterior occipital cortex, as well as bilateral prefrontal and occipitoparietal (OP) white matter (WM).

RESULTS

A significant main effect of site was found in βNTP/TP (Boston > SLC) and phosphocreatine/TP (Boston < SLC) in most cortical and WM regions, and inorganic phosphate/TP (Boston < SLC) in OP regions. A main effect analysis of BD diagnosis demonstrated a lower pH in posterior occipital cortex and right OP WM and a lower βNTP/TP in right prefrontal WM in BD subjects, compared to HC subjects.

CONCLUSION

The study showed that there were cerebral bioenergetic differences in both BD and HC veteran participants at two different sites, which may be partly explained by altitude difference. Future studies are needed to replicate these results in order to elucidate the dysfunctional mitochondrial changes that occur in response to hypobaric hypoxia.

Ethanol and cognition: indirect effects, neurotoxicity and neuroprotection: a review

Ethanol affects cognition in a number of ways. Indirect effects include intoxication, withdrawal, brain trauma, central nervous system infection, hypoglycemia, hepatic failure, and Marchiafava-Bignami disease. Nutritional deficiency can cause pellagra and Wernicke-Korsakoff disorder. Additionally, ethanol is a direct neurotoxin and in sufficient dosage can cause lasting dementia. However, ethanol also has neuroprotectant properties and in low-to-moderate dosage reduces the risk of dementia, including Alzheimer type. In fetuses ethanol is teratogenic, and whether there exists a safe dose during pregnancy is uncertain and controversial.

Brain cell membrane motion-restricted phospholipids: a cerebral 31-phosphorus magnetic resonance spectroscopy study of patients with schizophrenia

This study directly assessed, for the first time, whether there was a change in brain cell motion-restricted membrane phospholipids in vivo in patients with schizophrenia with mild to moderate negative symptoms, by quantification of the underlying broad resonance signal of cerebral 31-phosphorus magnetic resonance scans. Cerebral 31-phosphorus magnetic resonance spectroscopy was carried out in 16 schizophrenia patients and 16 age- and gender-matched normal controls. Spectra were obtained from 70x70x70 mm3 voxels using an image-selected in vivo spectroscopy pulse sequence. There was no significant difference in the broad resonances between the two groups, with the mean (S.E.) percentage signal being 59.4 (5.6) for the patients and 53.5 (5.9) for the controls. The phosphomonoesters and phosphodiesters narrow signals also did not differ significantly, their ratio being 0.26 (0.01) in the patients and 0.25 (0.01) in the controls. These results appear to be at variance with the changes expected under the membrane phospholipid hypothesis of schizophrenia.

MR spectroscopy: its potential role for drug development for the treatment of psychiatric diseases

Magnetic resonance spectroscopy (MRS) is likely in the near future to play a key role in the process of drug discovery and evaluation. As the pharmaceutical industry seeks biochemical markers of drug delivery, efficacy and toxicity, this non-invasive technique offers numerous ways to study adults and children repeatedly and without ionizing radiation. In this article, we survey an array of the information that MRS offers about neurochemistry in general and psychiatric disorders and their treatment in particular. We also present growing evidence of glial abnormalities in neuropsychiatric disorders and discuss what MRS is contributing to that line of investigation. The third major direction of this article is the discussion of where MRS techniques are headed and how those new techniques can contribute to studies of mechanisms of psychiatric disease and drug discovery.

Cerebral phosphorus metabolite and transverse relaxation time abnormalities in heroin-dependent subjects at onset of methadone maintenance treatment

Cerebral bioenergetic and phospholipid abnormalities have been reported in heroin-dependent subjects. The goal of the present study was to characterize the neurochemical profile of subjects voluntarily enrolled in a methadone maintenance (MM) treatment program to overcome their heroin addiction. Participants included 43 heroin-dependent subjects during their first month of MM and 15 age-matched healthy individuals. Phosphorus magnetic resonance spectroscopy ((31)P MRS) and transverse relaxation times (T2-RT), which can reflect steady state cerebral perfusion and metabolism, were acquired at 1.5 T from an axial slice prescribed through the orbitofrontal and occipital cortices, including basal ganglia and frontal cortex. MM subjects exhibited reduced phosphocreatine (PCr) levels (-15.3%), elevated phosphodiesters (+ 12.9%, PDE) and significantly longer T2-RT ((+) 2.1%) compared with healthy comparison subjects. When MM subjects were stratified into subgroups based on treatment duration, we found a treatment duration effect on metabolite values but not T2-RT; reduced PCr was observed only after 8+ days of MM, and phosphomonoesters (PME) were elevated in the 15-28 day MM group. Taken together, these cross-sectional data suggest that the first month of MM treatment may be associated with altered cerebral bioenergetics and phospholipid metabolite levels.

S-adenosyl-L-methionine: effects on brain bioenergetic status and transverse relaxation time in healthy subjects

BACKGROUND

S-adenosyl-L-methionine is an effective treatment for clinical depression, although the mechanism underlying this effect is unclear. Presently, in vivo phosphorus magnetic resonance spectroscopy (31P MRS) and brain transverse relaxometry were employed to test if S-adenosyl-L-methionine supplementation alters brain bioenergetics and/or transverse relaxation time (T2RT) in a nondepressed cohort. If these magnetic resonance techniques are sensitive to S-adenosyl-L-methionine induced alterations in neurochemical processes, these methods may be used in cases of clinical depression to elucidate the mechanism underlying the antidepressant effect of S-adenosyl-L-methionine.

METHODS

Twelve subjects self-administered 1600 mg of oral S-adenosyl-L-methionine daily. Phosphorus spectra and transverse relaxation time were acquired at baseline and after treatment using a 1.5 Tesla scanner.

RESULTS

Phosphocreatine levels were significantly higher after treatment, whereas beta nucleoside triphosphate levels, predominantly adenosine triphosphate in brain, were significantly lower after treatment. A surprising gender difference in T2RT emerged after supplementation, with women exhibiting significantly lower T2RT than men.

CONCLUSIONS

Alterations in phosphocreatine and beta nucleoside triphosphate are consistent with the report that S-adenosyl-L-methionine is involved in the production of creatine, which in turn is phosphorylated to phosphocreatine using adenosine triphosphate. These findings suggest that S-adenosyl-L-methionine alters parameters associated with cerebral bioenergetic status and that some effects of S-adenosyl-L-methionine (T2RT) occur in a gender-specific manner.

Prior knowledge for time domain quantification of in vivo brain or liver 31P MR spectra

Prior knowledge is required when quantifying in vivo (31)P magnetic resonance spectra from the brain or liver. The prior knowledge system we have used models both the phosphomonoester and phosphodiester resonances as two peaks of equal linewidth and fixed relative chemical shift. The analysis of the data is carried out in the time domain, which allows the broad component of the spectra to be modelled. This prior knowledge method has been tested for analysis of in vivo (31)P MR spectra from the liver and brain and gives results consistent with other methods that are also used to analyse the spectra, but with reduced variability. This technique may be utilized for studies requiring serial MR spectroscopy examinations, before and after patient treatment.

Magnetic resonance spectroscopy and its applications in psychiatry

OBJECTIVE

This paper briefly describes neuroimaging using magnetic resonance spectroscopy (MRS) and provides a systematic review of its application to psychiatric disorders.

METHOD

A literature review (Index Medicus/Medline) was carried out, as well as a review of other relevant papers and data known to the authors.

RESULTS

Magnetic resonance spectroscopy is a complex and sophisticated neuroimaging technique that allows reliable and reproducible quantification of brain neurochemistry provided its limitations are respected. In some branches of medicine it is already used clinically, for instance, to diagnose tumours and in psychiatry its applications are gradually extending beyond research. Neurochemical changes have been found in a variety of brain regions in dementia, schizophrenia and affective disorders and promising discoveries have also been made in anxiety disorders.

CONCLUSION

Magnetic resonance spectroscopy is a non-invasive investigative technique that has provided useful insights into the biochemical basis of many neuropsychiatric disorders. It allows direct measurement, in vivo, of medication levels within the brain and has made it possible to track the neurochemical changes that occur as a consequence of disease and ageing or in response to treatment. It is an extremely useful advance in neuroimaging technology and one that will undoubtedly have many clinical uses in the near future.

A profile of neuropsychological deficits in alcoholic women

Neuropsychological deficits, most notable in executive, visuospatial, and functions of gait and balance, are detectable in alcoholic men even after a month of sobriety. Less well established are the severity and profile of persisting deficits in alcoholic women. The authors used an extensive test battery to examine cognitive and motor functions in 43 alcoholic women who were sober, on average, for 3.6 months. Functions most severely affected in alcoholic women involved visuospatial and verbal and nonverbal working memory processes as well as gait and balance. Areas of relative sparing were executive functions, declarative memory, and upper-limb strength and speed. The authors found that lifetime alcohol consumption was related to impairment severity on Block Design (Wechsler Adult Intelligence Scale-Revised, D. Wechsler, 1981) and verbal and nonverbal working memory, suggesting a dose effect of alcohol abuse. The alcohol-related deficits in working memory, visuospatial, and balance implicate disruption of prefrontal, superior parietal, and cerebellar brain systems.

Current awareness

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of NMR in biomedicine. Each bibliography is divided into 9 sections: 1 Books, Reviews ' Symposia; 2 General; 3 Technology; 4 Brain and Nerves; 5 Neuropathology; 6 Cancer; 7 Cardiac, Vascular and Respiratory Systems; 8 Liver, Kidney and Other Organs; 9 Muscle and Orthopaedic. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.