Nutrition and alcoholic encephalopathies

Wernicke encephalopathy with atypical imaging findings in a depressed patient: A case report

This case report highlights the rare occurrence of Wernicke encephalopathy caused by malnutrition in a depressed patient with atypical imaging findings. A 60-year-old female with depression developed a disturbance of consciousness owing to Wernicke encephalopathy. Magnetic resonance imaging showed abnormal signals in the thalamus and mammillary bodies around the third ventricle, cerebral aqueduct, and fourth ventricle. Abnormal signals were also present in the cerebral cortex around the central sulcus, and an intracranial hemorrhage from the thalamus was observed. Therefore, clinicians should consider Wernicke encephalopathy in the differential diagnosis of altered consciousness in depressed patients. Early assessment of nutritional status and prompt intervention are crucial in cases of prolonged depression-related malnutrition.

SLC19A1 Genetic Variation Leads to Altered Thiamine Diphosphate Transport: Implications for the Risk of Developing Wernicke-Korsakoff's Syndrome

AIMS

Wernicke-Korsakoff syndrome (WKS) is commonly associated with chronic alcohol misuse, a condition known to have multiple detrimental effects on thiamine metabolism. This study was conducted to identify genetic variants that may contribute to the development of WKS in individuals with alcohol dependence syndrome through alteration of thiamine transport into cells.

METHODS

Exome sequencing data from a panel of genes related to alcohol metabolism and thiamine pathways were analysed in a discovery cohort of 29 individuals with WKS to identify possible genetic risk variants associated with its development. Variant frequencies in this discovery cohort were compared with European frequencies in the Genome Aggregation Database browser, and those present at significantly higher frequencies were genotyped in an additional cohort of 87 alcohol-dependent cases with WKS and 197 alcohol-dependent cognitively intact controls.

RESULTS

Thirty non-synonymous variants were identified in the discovery cohort and, after filtering, 23 were taken forward and genotyped in the case-control cohort. Of these SLC19A1:rs1051266:G was nominally associated with WKS. SLC19A1 encodes the reduced folate carrier, a major transporter for physiological folate in plasma; rs1051266 is reported to impact folate transport. Thiamine pyrophosphate (TPP) efflux was significantly decreased in HEK293 cells, stably transfected with rs1051266:G, under thiamine deficient conditions when compared with the efflux from cells transfected with rs1051266:A (P = 5.7 × 10-11).

CONCLUSION

This study provides evidence for the role of genetic variation in the SLC19A1 gene, which may contribute to the development of WKS in vivo through modulation of TPP transport in cells.

Sex differences in cholinergic circuits and behavioral disruptions following chronic ethanol exposure with and without thiamine deficiency

BACKGROUND

Few studies have investigated differences in the vulnerabilities of males and females to alcohol use disorder and alcohol-related brain damage (ARBD). According to epidemiological and clinical findings, females appear to be more sensitive to the effects of alcohol and thiamine deficiency and have a worse prognosis in recovery from neurocognitive deficits compared with males. This study aimed to characterize the effects of chronic ethanol (EtOH) toxicity and thiamine deficiency across the sexes using rodent models.

METHODS

Male and female Sprague Dawley rats were assigned to chronic forced EtOH treatment (CET), pyrithiamine-induced thiamine deficiency (PTD), combined CET-PTD, or pair-fed (PF) control treatment conditions. Following treatments, spatial working memory was assessed during a spontaneous alternation task while measuring acetylcholine (ACh) in the prefrontal cortex (PFC) and the hippocampus (HPC). The animals also underwent an operant-based attentional set-shifting task (ASST) for the analysis of behavioral flexibility.

RESULTS

Female and male rats did not differ in terms of EtOH consumption; however, the CET and CET-PTD-treated female rats had lower BECs than male rats. Compared with the PF group, the CET, PTD, and CET-PTD groups exhibited spatial working memory impairments with corresponding reductions in ACh efflux in the PFC and HPC. The ASST revealed that CET-PTD-treated males and females displayed impairments marked by increased latency to make decisions. Thalamic shrinkage was prominent only in the CET-PTD and PTD treatment conditions, but no sex-specific effects were observed.

CONCLUSIONS

Although the CET and CET-PTD-treated females had lower BECs than the males, they demonstrated similar cognitive impairments. These results provide evidence that female rats experience behavioral and neurochemical disruptions at lower levels of alcohol exposure than males and that chronic EtOH and thiamine deficiencies produce a unique behavioral profile.

Jacobian Mapping Reveals Converging Brain Substrates of Disruption and Repair in Response to Ethanol Exposure and Abstinence in 2 Strains of Rats

BACKGROUND

In a previous study using Jacobian mapping to evaluate the morphological effects on the brain of binge (4-day) intragastric ethanol (EtOH) on wild-type Wistar rats, we reported reversible thalamic shrinkage and lateral ventricular enlargement, but persistent superior and inferior colliculi shrinkage in response to binge EtOH treatment.

METHODS

Herein, we used similar voxel-based comparisons of Magnetic Resonance Images collected in EtOH-exposed relative to control animals to test the hypothesis that regardless of the intoxication protocol or the rat strain, the hippocampi, thalami, and colliculi would be affected.

RESULTS

Two experiments [binge (4-day) intragastric EtOH in Fisher 344 rats and chronic (1-month) vaporized EtOH in Wistar rats] showed similarly affected brain regions including retrosplenial and cingulate cortices, dorsal hippocampi, central and ventroposterior thalami, superior and inferior colliculi, periaqueductal gray, and corpus callosum. While most of these regions showed significant recovery, volumes of the colliculi and periaqueductal gray continued to show response to each proximal EtOH exposure but at diminished levels with repeated cycles.

CONCLUSIONS

Given the high metabolic rate of these enduringly affected regions, the current findings suggest that EtOH per se may affect cellular respiration leading to brain volume deficits. Further, responsivity greatly diminished likely reflecting neuroadaptation to repeated alcohol exposure. In summary, this unbiased, in vivo-based approach demonstrating convergent brain systems responsive to 2 EtOH exposure protocols in 2 rat strains highlights regions that warrant further investigation in both animal models of alcoholism and in humans with alcohol use disorder.

Effects of Mild and Severe Vitamin B1 Deficiencies on the Meiotic Maturation of Mice Oocytes

We investigated the effects of vitamin B₁ deficiency on the meiosis maturation of oocytes. Female Crl:CD1 (ICR) mice were fed a 20% casein diet (control group) or a vitamin B₁–free diet (test group). The vitamin B₁ concentration in ovary was approximately 30% lower in the test group than in the control group. Oocyte meiosis was not affected by vitamin B₁ deficiency when the deficiency was not accompanied by body weight loss. On the contrary, frequency of abnormal oocyte was increased by vitamin B₁ deficiency when deficiency was accompanied by body weight loss (referred to as severe vitamin B₁ deficiency; frequency of abnormal oocyte, 13.8% vs 43.7%, P = .0071). The frequency of abnormal oocytes was decreased by refeeding of a vitamin B₁–containing diet (13.9% vs 22.9%, P = .503). These results suggest that severe vitamin B₁ deficiency inhibited meiotic maturation of oocytes but did not damage immature oocytes.

Simultaneous Determination of Underivatized Vitamin B1 and B6 in Whole Blood by Reversed Phase Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry

Background

Vitamin B1 (thiamine-diphosphate) and B6 (pyridoxal-5’phosphate) are micronutrients. Analysis of these micronutrients is important to diagnose potential deficiency which often occurs in elderly people due to malnutrition, in severe alcoholism and in gastrointestinal compromise due to bypass surgery or disease. Existing High Performance Liquid Chromatography (HPLC) based methods include the need for derivatization and long analysis time. We developed an Ultra High Performance Liquid Chromatography Tandem Mass spectrometry (UHPLC-MS/MS) assay with internal standards for simultaneous measurement of underivatized thiamine-diphosphate and pyridoxal-5’phosphate without use of ion pairing reagent.

Methods

Whole blood, deproteinized with perchloric acid, containing deuterium labelled internal standards thiamine-diphosphate(thiazole-methyl-D₃) and pyridoxal-5’phosphate(methyl-D₃), was analyzed by UHPLC-MS/MS. The method was validated for imprecision, linearity, recovery and limit of quantification. Alternate (quantitative) method comparisons of the new versus currently used routine HPLC methods were established with Deming regression.

Results

Thiamine-diphosphate and pyridoxal-5’phosphate were measured within 2.5 minutes instrumental run time. Limits of detection were 2.8 nmol/L and 7.8 nmol/L for thiamine-diphosphate and pyridoxal-5’phosphate respectively. Limit of quantification was 9.4 nmol/L for thiamine-diphosphate and 25.9 nmol/L for pyridoxal-5’phosphate. The total imprecision ranged from 3.5–7.7% for thiamine-diphosphate (44–157 nmol/L) and 6.0–10.4% for pyridoxal-5’phosphate (30–130 nmol/L). Extraction recoveries were 101–102% ± 2.5% (thiamine-diphosphate) and 98–100% ± 5% (pyridoxal-5’phosphate). Deming regression yielded slopes of 0.926 and 0.990 in patient samples (n = 282) and national proficiency testing samples (n = 12) respectively, intercepts of +3.5 and +3 for thiamine-diphosphate (n = 282 and n = 12) and slopes of 1.04 and 0.84, intercepts of -2.9 and +20 for pyridoxal-5’phosphate (n = 376 and n = 12).

Conclusion

The described UHPLC-MS/MS method allows simultaneous determination of underivatized thiamine-diphosphate and pyridoxal-5’phosphate in whole blood without intensive sample preparation.

Change in psychiatric symptomatology after benfotiamine treatment in males is related to lifetime alcoholism severity

BACKGROUND

Severe alcoholism can be associated with significant nutritional and vitamin deficiency, especially vitamin B1 (thiamine) which is associated with neurological deficits impacting mood and cognition. Alcohol consumption was reduced among female but not male alcoholics after supplementation with the high potency thiamine analog benfotiamine (BF). We examined the relationship between lifetime alcoholism severity, psychiatric symptoms and response to BF among the alcohol dependent men from this cohort.

METHODS

Eighty-five adult men (mean age=48±8 years) meeting DSM-IV-TR criteria for a current alcohol use disorder who were abstinent <30days participated in a randomized, double-blind, placebo-controlled trial of 600mg BF vs placebo (PL) for 6 months. Psychometric testing included a derived Lifetime Alcoholism Severity Score (AS), Symptom Checklist 90R (SCL-90R), and the Barratt Impulsivity Scale (BIS) at baseline and at 6 months.

RESULTS

Baseline SCL-90-R scale scores for men with high alcoholism severity (AS≥24; N=46 HAS) were significantly greater than for men with low alcoholism severity (AS<24; N=39 LAS), but BIS scores did not differ. MANOVA modeling at follow-up (N=50 completed subjects) identified a significant treatment effect (F=2.5, df=10, p<0.03) and treatment×alcoholism severity level interaction (F=2.5, dfnum=10, dfden=30, p<0.03) indicating reduced SCL-90-R scores among BF treated, HAS males. Above normal plasma thiamine levels at follow-up predicted reduced depression scores in a BF-treated subset (F=3.2, p<0.09, N=26).

CONCLUSION

BF appears to reduce psychiatric distress and may facilitate recovery in severely affected males with a lifetime alcohol use disorder and should be considered for adjuvant therapy in alcohol rehabilitation.

TRIAL REGISTRATION

#NCT00680121 High Dose Vitamin B1 to Reduce Abusive Alcohol Use.

Host-microbiome interactions in alcoholic liver disease

Alcoholic liver disease is a leading cause of morbidity and liver-related death worldwide. Intestinal bacterial overgrowth and dysbiosis induced by ethanol ingestion play an important role in the pathogenesis of alcoholic liver disease. After exposure to alcohol in the lumen, enteric bacteria alter their metabolism and thereby disturb intestinal homeostasis. Disruption of the mucosal barrier results in the translocation of microbial products that contribute to liver disease by inducing hepatic inflammation. In this review, we will discuss the effects of alcohol on the intestinal microbiome, and in particular, its effects on bacterial metabolism, bacterial translocation and ecological balance. A better understanding of the interactions among alcohol, the host and the microbiome will reveal new targets for therapy and lead to new treatments.

Thiamine deficiency: an update of pathophysiologic mechanisms and future therapeutic considerations

Thiamine is an essential vitamin that is necessary to maintain the functional integrity of cells in the brain. Its deficiency is the underlying cause of Wernicke's encephalopathy (WE), a disorder primarily associated with, but not limited to, chronic alcoholism. Thiamine deficiency leads to the development of impaired energy metabolism due to mitochondrial dysfunction in focal regions of the brain resulting in cerebral vulnerability. The consequences of this include oxidative stress, excitotoxicity, inflammatory responses, decreased neurogenesis, blood-brain barrier disruption, lactic acidosis and a reduction in astrocyte functional integrity involving a loss of glutamate transporters and other astrocyte-specific proteins which together contribute in a major way to the resulting neurodegeneration. Exactly how these factors acting in concert lead to the demise of neurons is unclear. In this review we reassess their relative importance in the light of more recent findings and discuss therapeutic possibilities that may provide hope for the future for individuals with WE.

Chronic alcohol consumption and its effect on nodes of frontocerebellar and limbic circuitry: comparison of effects in France and the United States

Alcohol use disorders present a significant public health problem in France and the United States (U.S.), but whether the untoward effect of alcohol on the brain results in similar damage in both countries remains unknown. Accordingly, we conducted a retrospective collaborative investigation between two French sites (Caen and Orsay) and a U.S. laboratory (SRI/Stanford University) with T1-weighted, structural MRI data collected on a common imaging platform (1.5T, General Electric) on 288 normal controls (NC), 165 uncomplicated alcoholics (ALC), and 26 patients with alcoholic Korsakoff's syndrome (KS) diagnosed at all sites with a common interview instrument. Data from the two countries were pooled, then preprocessed and analyzed together at the U.S. site using atlas-based parcellation. National differences indicated that thalamic volumes were smaller in ALC in France than the U.S. despite similar alcohol consumption levels in both countries. By contrast, volumes of the hippocampus, amygdala, and cerebellar vermis were smaller in KS in the U.S. than France. Estimated amount of alcohol consumed over a lifetime, duration of alcoholism, and length of sobriety were significant predictors of selective regional brain volumes in France and in the U.S. The common analysis of MRI data enabled identification of discrepancies in brain volume deficits in France and the U.S. that may reflect fundamental differences in the consequences of alcoholism on brain structure between the two countries, possibly related to genetic or environmental differences.

Double-blind, randomized placebo-controlled clinical trial of benfotiamine for severe alcohol dependence

Alcohol dependence is associated with severe nutritional and vitamin deficiency. Vitamin B1 (thiamine) deficiency erodes neurological pathways that may influence the ability to drink in moderation. The present study examines tolerability of supplementation using the high-potency thiamine analog, benfotiamine (BF), and BF's effects on alcohol consumption in severely affected, self-identified, alcohol dependent subjects. A randomized, double-blind, placebo-controlled trial was conducted on 120 non-treatment seeking, actively drinking, alcohol dependent men and women volunteers (mean age=47 years) from the Kansas City area who met DSM-IV-TR criteria for current alcohol dependence. Subjects were randomized to receive 600 mg benfotiamine or placebo (PL) once daily by mouth for 24 weeks with 6 follow-up assessments scheduled at 4 week intervals. Side effects and daily alcohol consumption were recorded. Seventy (58%) subjects completed 24 weeks of study (N=21 women; N=49 men) with overall completion rates of 55% (N=33) for PL and 63% (N=37) for BF groups. No significant adverse events were noted and alcohol consumption decreased significantly for both treatment groups. Alcohol consumption decreased from baseline levels for 9 of 10 BF treated women after 1 month of treatment compared with 2 of 11 on PL. Reductions in total alcohol consumption over 6 months were significantly greater for BF treated women (BF: N=10, -611 ± 380 standard drinks; PL: N=11, -159 ± 562 standard drinks, p-value=0.02). BF supplementation of actively drinking alcohol dependent men and women was well-tolerated and may discourage alcohol consumption among women. The results do support expanded studies of BF treatment in alcoholism.

Focal thalamic degeneration from ethanol and thiamine deficiency is associated with neuroimmune gene induction, microglial activation, and lack of monocarboxylic acid transporters

Background

Wernicke's encephalopathy-Korsakoff syndrome (WE-KS) is common in alcoholics, caused by thiamine deficiency (TD; vitamin B1) and associated with lesions to the thalamus (THAL). Although TD alone can cause WE, the high incidence in alcoholism suggests that TD and ethanol (EtOH) interact.

Methods

Mice in control, TD, or EtOH groups alone or combined were studied after 5 or 10 days of treatment. THAL and entorhinal cortex (ENT) histochemistry and mRNA were assessed.

Results

Combined EtOH-TD treatment for 5 days (EtOH-TD5) showed activated microglia, proinflammatory gene induction and THAL neurodegeneration that was greater than that found with TD alone (TD5), whereas 10 days resulted in marked THAL degeneration and microglial-neuroimmune activation in both groups. In contrast, 10 days of TD did not cause ENT degeneration. Interestingly, in ENT, TD10 activated microglia and astrocytes more than EtOH-TD10. In THAL, multiple astrocytic markers were lost consistent with glial cell loss. TD blocks glucose metabolism more than acetate. Acetate derived from hepatic EtOH metabolism is transported by monocarboxylic acid transporters (MCT) into both neurons and astrocytes that use acetyl-CoA synthetase (AcCoAS) to generate cellular energy from acetate. MCT and AcCoAS expression in THAL is lower than ENT prompting the hypothesis that focal THAL degeneration is related to insufficient MCT and AcCoAS in THAL. To test this hypothesis, we administered glycerin triacetate (GTA) to increase blood acetate and found it protected the THAL from TD-induced degeneration.

Conclusions

Our findings suggest that EtOH potentiates TD-induced THAL degeneration through neuroimmune gene induction. The findings support the hypothesis that TD deficiency inhibits global glucose metabolism and that a reduced ability to process acetate for cellular energy results in THAL focal degeneration in alcoholics contributing to the high incidence of Wernicke-Korsakoff syndrome in alcoholism.

Thiamine for prevention and treatment of Wernicke-Korsakoff Syndrome in people who abuse alcohol

BACKGROUND

Autopsy studies suggest that Wernicke-Korsakoff syndrome (WKS) is not a rare disorder, particularly in individuals who abuse alcohol. Thiamine has been established as the treatment of choice for over 50 years, but uncertainty remains about appropriate dosage and duration. Current practice guidelines are based on case reports and clinical experience. This is an update of a review first published in 2004 and last updated in 2008.

OBJECTIVES

• To assess the efficacy of thiamine in preventing and treating the manifestations of WKS due to excess alcohol consumption. • To determine the optimum form, dose and duration of thiamine treatment for this indication.

SEARCH METHODS

ALOIS, the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG), The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL and LILACS were searched on 6 September 2012 using the term thiamine OR aneurine. ALOIS contains records from all major health care databases (The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS) as well as from many trial databases and grey literature sources.

SELECTION CRITERIA

Any randomised trials comparing thiamine with alternative interventions or comparing different thiamine regimens (varying in formulation, dose or duration of administration).

DATA COLLECTION AND ANALYSIS

All abstracts were independently inspected by two reviewers (ED and PWB), and relevant articles were retrieved and assessed for methodological quality using criteria provided in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

Two studies were identified that met the inclusion criteria, but only one contained sufficient data for quantitative analysis. Ambrose (2001) randomly assigned participants (n = 107) to one of five doses of intramuscular thiamine and measured outcomes after 2 days of treatment. We compared the lowest dose (5 mg/day) with each of the other four doses. A significant difference favoured 200 mg/day compared with the 5-mg/day dose in determining the number of trials needed to meet inclusion criteria on a delayed alternation test (mean difference (MD) -17.90, 95% confidence interval (CI) -35.4 to -0.40, P = 0.04). No significant differences emerged when the other doses were compared with 5 mg/day. The pattern of results did not reflect a simple dose-response relationship. The study had methodological shortcomings in design and in the presentation of results that limited further analysis.

AUTHORS' CONCLUSIONS

Evidence from randomised controlled clinical trials is insufficient to guide clinicians in determining the dose, frequency, route or duration of thiamine treatment for prophylaxis against or treatment of WKS due to alcohol abuse.

The evolution and treatment of Korsakoff's syndrome: out of sight, out of mind?

Wernicke's Encephalopathy is an acute neuro-psychiatric condition caused by an insufficient supply of thiamine (Vitamin B1) to the brain. If undiagnosed or inadequately treated, it is likely to proceed to Korsakoff's Syndrome. Wernicke's Encephalopathy can result from dietary deficiency alone and this form is usually successfully treated, with little chance of Korsakoff's Syndrome supervening. On the other hand, thiamine deficiency associated with alcohol misuse/dependence may require up to 1 gram of thiamine IV in the first 24 hours to be treated successfully. The reasons for this difference in treatment will be discussed. Thiamine diphosphate acts as a co-factor for a number of thiamine-dependent enzymes. Thiamine deficiency leads to a reduction in the activity of these enzymes, and this leads to alterations in mitochondrial activity, impairment of oxidative metabolism, decreased energy status and eventually selective neuronal death. The damage caused by the combination of thiamine deficiency and alcohol metabolism probably interferes with adequate thiamine transport at a number of sites in the body, including the blood-brain barrier, as well as causing damage to the apoenzymes which then require higher concentrations of thiamine to work normally. The accumulated damage is likely to render the use of oral thiamine therapeutically inadequate since the body is unable to produce high enough concentrations of thiamine in the blood to traverse the blood-brain barrier. Some individuals are probably genetically predisposed to develop Wernicke's. Long before individuals with alcohol misuse or dependence develop Wernicke's Encephalopathy the neurons and other cells of the body are functioning sub-optimally because of the inadequate supply of thiamine and the neurotoxic effect of alcohol. This relative deficiency initiates a series of pathological changes which accumulate and further interfere with the supply of thiamine and its utilisation at a time when the requirements are increased. The best treatment for Korsakoff's Syndrome is timely recognition of Wernicke's Encephalopathy and appropriate intervention and prevention.

Clinical and pathological features of alcohol-related brain damage

One of the sequelae of chronic alcohol abuse is malnutrition. Importantly, a deficiency in thiamine (vitamin B(1)) can result in the acute, potentially reversible neurological disorder Wernicke encephalopathy (WE). When WE is recognized, thiamine treatment can elicit a rapid clinical recovery. If WE is left untreated, however, patients can develop Korsakoff syndrome (KS), a severe neurological disorder characterized by anterograde amnesia. Alcohol-related brain damage (ARBD) describes the effects of chronic alcohol consumption on human brain structure and function in the absence of more discrete and well-characterized neurological concomitants of alcoholism such as WE and KS. Through knowledge of both the well-described changes in brain structure and function that are evident in alcohol-related disorders such as WE and KS and the clinical outcomes associated with these changes, researchers have begun to gain a better understanding of ARBD. This Review examines ARBD from the perspective of WE and KS, exploring the clinical presentations, postmortem brain pathology, in vivo MRI findings and potential molecular mechanisms associated with these conditions. An awareness of the consequences of chronic alcohol consumption on human behavior and brain structure can enable clinicians to improve detection and treatment of ARBD.

Signs of preclinical Wernicke's encephalopathy and thiamine levels as predictors of neuropsychological deficits in alcoholism without Korsakoff's syndrome

The purpose of this study was to determine whether meeting historical criteria for unsuspected Wernicke's encephalopathy (WE), largely under-diagnosed in vivo, explains why some alcoholics have severe neuropsychological deficits, whereas others, with a similar drinking history, exhibit preserved performance. Demographic, clinical, alcohol related, and neuropsychological measures were collected in 56 abstinent alcoholics and 38 non-alcohol-dependent volunteers. Alcoholics were classified using the clinical criteria established by Caine et al (1997) and validated in their neuropathological study of alcoholic cases. Our alcoholics who met a single criterion were considered 'at risk for WE' and those with two or more criteria with 'signs of WE'. Whole blood thiamine was also measured in 22 of the comparison group and 28 alcoholics. Of the alcoholics examined, 27% met no criteria, 57% were at risk for WE, and 16% had signs of WE. Neuropsychological performance of the alcoholic subgroups was graded, with those meeting zero criteria not differing from controls, those meeting one criterion presenting mild-to-moderate deficits on some of the functional domains, and those meeting two or more criteria having the most severe deficits on each of the domains examined. Thiamine levels were selectively related to memory performance in the alcoholics. Preclinical signs of WE can be diagnosed in vivo, enabling the identification of ostensibly 'uncomplicated' alcoholics who are at risk for neuropsychological complications. The graded effects in neuropsychological performance suggest that the presence of signs of WE explains, at least partially, the heterogeneity of alcoholism-related cognitive and motor deficits.

Pontocerebellar volume deficits and ataxia in alcoholic men and women: no evidence for "telescoping"

INTRODUCTION

Brain volume shrinkage is common in treatment-seeking patients with alcohol use disorders. Whether women are more vulnerable to brain dysmorphology than men despite lower alcohol consumption levels or shorter dependency ("telescoping effect") remains controversial and has not been considered with respect to infratentorial structures or their potential contribution to ataxia.

METHODS

The 200 participants included 64 men and 31 women with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition alcohol dependence and 105 controls. An infratentorial region (pons, cerebellar hemispheres, vermis (anterior, posterior, and inferior sectors), fissures, cisterns, fourth ventricle) was quantified with atlas-based parcellation. To enable comparison of men and women, regional tissue volumes were expressed as ratios of tissue in the volume. Participants also completed quantitative ataxia testing.

RESULTS

Total infratentorial and vermian tissue ratios were significantly smaller in alcoholics than controls; alcoholic women did not show disproportionately greater volume deficits than alcoholic men. A re-analysis including alcoholic men and women matched in alcohol consumption, onset age, abstinence duration, and age revealed again that alcoholic women did not have disproportionately greater regional vermian volume deficits than alcoholic men. Alcoholic men and women were impaired in all measures of ataxia, which correlated with low infratentorial tissue ratios in men.

DISCUSSION

Alcoholic men showed deficits of pontocerebellar volume ratios, yet alcoholic women did not display signs of "telescoping". Further, alcoholic men and women both showed signs of ataxia of gait and balance, related to affected pontocerebellar systems in the men but not the women, suggesting the need to consider other neural substrates for ataxia in women.

Neuroimaging of the Wernicke-Korsakoff syndrome

AIM

Presented is the neuroradiological signature of acute Wernicke's encephalopathy (WE), derived from different types of magnetic resonance imaging (MRI) sequences. WE results from thiamine depletion, and its most typical antecedent is chronic alcohol dependence. Brain regions observed with in vivo MRI affected in acute WE include the mammillary bodies, periaqueductal and periventricular gray matter, collicular bodies and thalamus. These affected areas are usually edematous and are best visualized and quantified with MRI sequences that highlight such tissue. Following the acute WE phase and resolution of edema and inflammation of affected brain tissue, WE, if not adequately treated with thiamine repletion, can herald Korsakoff's syndrome (KS), with its symptomatic hallmark of global amnesia, that is, the inability to commit newly encountered (episodic) information to memory for later recall or recognition.

METHODS

Neuropathology of KS detectable with MRI has a different neuroradiological signature from the acute stage and can be observed as tissue shrinkage or atrophy of selective brain structures, including the mammillary bodies and thalamus and ventricular expansion, probably indicative of atrophy of surrounding gray matter nuclei. Quantification of these and additional gray matter structures known to underlie global amnesia reveal substantial bilateral volume deficits in the hippocampus, in addition to the mammillary bodies and thalamus, and modest deficits in the medial septum/diagonal band of Broca. The infratentorium is also affected, exhibiting volume deficits in cerebellar hemispheres, anterior superior vermis and pons, contributing to ataxia of gait and stance.

RESULTS

Consideration of WKS structural brain changes in the context of the neuropathology of non-WKS alcoholism revealed a graded pattern of volume deficits, from mild in non-WKS alcoholics to moderate or severe in WKS, in the mammillary bodies, hippocampus, thalamus, cerebellum and pons. The development and resolution of brain structures affected in acute, chronic and treated WE was verified in longitudinal MRI study of rats that modeled of the interaction of extensive alcohol consumption and thiamine depletion and repletion.

CONCLUSIONS

Thus, neuroradiological examination with MRI is valuable in the diagnosis of acute WE and enables in vivo tracking of the progression of the brain pathology of WE from the acute pathological phase to resolution with thiamine treatment or to progression to KS without treatment. Further, in vivo MRI facilitates translational studies to model antecedent conditions contributing to the development, sequelae and treatment of WE.

Wernicke-Korsakoff syndrome

Alcohol abuse is one of the most serious problems in public health and the Wernicke-Korsakoff syndrome is one of the gravest consequences of alcoholism. The pathology is often undiagnosed in its less evident presentations, therefore an accurate diagnostic approach is a critical step in treatment planning. Treatment is based on restoration of thiamine, although this is insufficient to prevent the psychological decline of a great number of patients. The cognitive impact of the pathology is derived from the interaction of alcoholic neurotoxicity, thiamine deficiency and personal susceptibility. In this article, the literature concerning Wernicke-Korsakoff syndrome is reviewed.

Neuronal cell death in Wernicke's encephalopathy: pathophysiologic mechanisms and implications for PET imaging

Thiamine deficiency in humans is associated with Wernicke's encephalopathy (WE) which is characterized neuropathologically by neuronal loss in selective brain regions. Pyrithiamine-induced thiamine-deficiency in the rat results in lesions which are similar in nature and distribution to those seen in human WE. Several mechanisms have been implicated in the pathogenesis of neuronal loss in thiamine deficiency including, (i) impaired cerebral energy metabolism, (ii) focal lactic acidosis, (iii) NMDA-receptor mediated excitotoxicity and (iv) blood-brain barrier breakdown. WE is difficult to diagnose during life and a large number of cases are missed by routine clinical neurological evaluation. Recently, non-invasive diagnostic procedures such as CT and MRI have been used for the evaluation of acute and chronic WE. Autoradiographic studies reveal that increased densities of binding sites for the astrocytic ligand 3H-PK11195 closely parallel the topographic distribution of reactive gliosis and neuronal loss in selective brain regions of pyrithiamine-induced thiamine-deficient rats. In contrast, binding sites for the neuronal ligand 3H-Ro15-1788 show poor regional correlation with neuronal loss in thiamine deficiency. Both of these ligands are available, and have been used in PET assessment of various disorders in humans. The results of autoradiographic studies suggest that 11C-PK11195 may offer a useful PET ligand for the assessment of brain damage in WE in humans.

The neurochemical pathology of thiamine deficiency: GABAA and glutamateNMDA receptor binding sites in a goat model

Synaptic plasma membranes were prepared from four cerebrocortical areas from six male Angora goats made chronically thiamine deficient (TD) by the administration of AmproliumTM (600-900 mg/kg daily for 38-44 d). Four male controls were matched for age (27-30 mo). Four different radioligands were used to characterise GABAA and Glu-RNMDA receptor binding sites. There were marked, localised and contrasting changes in motor cortex, with an increase in GABAA and a decrease in Glu-RNMDA binding site densities. Less clearcut changes of a similar nature were seen in visual cortex. There was no variation in the parameters of GABA-activated [3H]diazepam binding between cortical areas in control goats, but there was a reduction in the maximal response to GABA in all areas in TD goats. There were regional variations in glutamate-activated [3H]MK-801 binding in control goat brain, and a non-selectively reduced maximal response in TD. Alterations in these indices of GABA- and glutamate-mediated neurotransmission may underlie the neurological signs of acute thiamine deficiency in these animals.

An international perspective on the prevalence of the Wernicke-Korsakoff syndrome

In the Western world previous studies have shown that the majority of cases of the Wernicke-Korsakoff syndrome (WKS), which is caused by thiamine deficiency, occur in alcoholics. However, in France, a country with one of the highest per capita consumptions of alcohol, the prevalence of the WKS was found to be only 0.4% in a small retrospective autopsy study. This figure is compared with data sent to the authors by a number of neuropathologists from the U.S.A., Europe, Scandinavia and Australia. There was no obvious correlation between the prevalence rates of the WKS, which were highest in Australia (2.8%-previously published), and per capita consumption of alcohol. Other issues such as diet, National programs for supplementation of foods with thiamine, and drinking habits are considered. The pathological diagnosis of the WKS can often be made on macroscopic examination of the brain after fixation in formalin. The mammillary bodies are smaller than normal in most cases of chronic WKS. However in this study it was found that the most common causes of small mammillary bodies were Alzheimer's disease and atrophy due to transneuronal degeneration secondary to lesions in the hippocampus.

Wernicke's encephalopathy and alcohol-related disease

A pilot study of 31 consecutive alcohol-related deaths over an 8-month period revealed the presence of histologically diagnosed Wernicke's encephalopathy in 17 cases. Analysis of the clinical records revealed that a disturbance of the mental state was the commonest finding and neurological signs were present in only 2 of the 17 cases (ataxia 1, peripheral neuropathy 1). Analysis of 22 ward admissions for Wernicke's encephalopathy during the same 8-month period revealed that the diagnosis is easily made when neurological deficits (ophthalmoplegia, ataxia) accompany mental changes and when Wernicke's encephalopathy is the predominant illness. In patients with established alcohol-related disease attention is often directed to the presenting illness so that Wernicke's encephalopathy may easily be overlooked as a cause of deterioration in the mental state in these patients. It is recommended that routine management of patients with alcohol-related disease should include thiamine even if neurological signs are absent.