Increased white matter hyperintensities in male methamphetamine abusers

The Effectiveness of Mindfulness in the Treatment of Methamphetamine Addiction Symptoms: Does Neuroplasticity Play a Role?

INTRODUCTION

Methamphetamine is a highly stimulating psychoactive drug that causes life-threatening addictions and affects millions of people around the world. Its effects on the brain are complex and include disturbances in the neurotransmitter systems and neurotoxicity. There are several known treatment methods, but their effectiveness is moderate. It must be emphasised that no drugs have been approved for treatment. For this reason, there is an urgent need to develop new, effective, and safe treatments for methamphetamine. One of the potential treatments is mindfulness meditation. In recent years, this technique has been researched extensively in the context of many neurological and psychiatric disorders.

METHODS

This review explores the use of mindfulness in the treatment of methamphetamine addiction. Searches were conducted in the PubMed/Medline, Research Gate, and Cochrane databases.

RESULTS

Ten studies were identified that used mindfulness-based interventions in the treatment of methamphetamine addiction. The results show that mindfulness is an effective form of reducing hunger, risk of relapses, stress indicators, depression, and aggression, alone or in combination with transcranial direct current stimulation (tDCS). Mindfulness also improved the cognitive function in addicts. The included studies used only behavioural measures. The potential mechanisms of mindfulness in addiction were explained, and it was proposed that it can induce neuroplasticity, alleviating the symptoms of addiction.

CONCLUSIONS

Evidence from the studies suggest that mindfulness may be an effective treatment option for methamphetamine addiction, used alone or in combination with tDCS. However, further high-quality research is required to establish the role of this treatment option in this field. The use of neuroimaging and neurophysiological measures is fundamental to understand the mechanisms of mindfulness.

Structural indices of brain aging in methamphetamine use disorder

BACKGROUND

Methamphetamine use is surging globally. It has been linked to premature stroke, Parkinsonism, and dementia, suggesting that it may accelerate brain aging.

METHODS

We performed a retrospective study to determine if structural indices of brain aging were more prevalent prior to old age (26 - 54 years) in individuals with Methamphetamine Use Disorder (MUD), who were in early abstinence (M ± SD = 22.1 ± 25.6 days) than in healthy control (HC) participants. We compared T1-weighted MRI brain scans in age- and sex-matched groups (n = 89/group) on three structural features of brain aging: the brain volume/cerebrospinal fluid (BV/CSF) index, volume of white matter hypointensities/lesions, and choroid plexus volume.

RESULTS

The MUD group had a lower mean BV/CSF index and larger volumes of white matter hypointensities and choroid plexus (p-values < 0.01). Regression analyses showed significant age-by-group effects, indicating different age trajectories of the BV/CSF index and choroid plexus volume, consistent with abnormal global brain atrophy and choroid plexus pathology in the MUD group. Significant age and group main effects reflected a larger volume of white matter hypointensities for older participants across groups and for the MUD group irrespective of age. None of the three measures of brain aging correlated significantly with recent use or duration of recent abstinence from methamphetamine.

CONCLUSIONS

Premature brain pathology, which may reflect cerebrovascular damage and dysfunction of the choroid plexus, occurs in people with MUD. Such pathology may affect cognition and thereby efficacy of behavioral treatments for MUD.

Risk factors for hippocampal cavities in a marginally housed population

Cavities in the hippocampus are morphological variants of uncertain significance. Aberrant neurodevelopment along with vascular and inflammatory etiologies have been proposed. We sought to characterize these cavities and their potential risk factors in a marginally housed population, with high rates of viral infection, addiction, and mental illness. (1) The volume of hippocampal cavities (HCavs) is greater in this highly multimorbid population compared to the general population. (2) Conventional vascular risk factors such as greater age and systolic blood pressure are associated with higher HCav volume. (3) Nonprescribed substance-related risk factors such as stimulant use or dependence, and smoking are associated with increased HCav volume independent of vascular risk factors. This is a retrospective analysis of an ongoing prospective study. We analyzed baseline data, including medical history, physical exam, psychiatric diagnosis, and MRI from a total of 375 participants. Hippocampal cavities were defined as spaces isointense to CSF on T1 MRI sequences, bounded on all sides by hippocampal tissue, with a volume of at least 1 mm³ . Risk factors were evaluated using negative binomial multiple regression. Stimulant use was reported by 87.3% of participants, with stimulant dependence diagnosed in 83.3% of participants. Prevalence of cavities was 71.6%, with a mean total bilateral HCav volume of 13.89 mm³ . On average, a 1 mmHg greater systolic blood pressure was associated with a 2.17% greater total HCav volume (95% CI = [0.57%, 3.79%], p = .0076), while each cigarette smoked per day trended toward a 2.69% greater total HCav volume (95% CI = [-0.87%, 5.54%], p = .058). A diagnosis of stimulant dependence was associated with a 95.6% greater total HCav volume (95% CI = [5.39%, 263.19%], p = .0335). Hypertension and diagnosis of stimulant dependence were associated with a greater total volume of HCav.

Sex differences in methamphetamine use disorder perused from pre-clinical and clinical studies: Potential therapeutic impacts

Methamphetamine (METH) use, and misuse are associated with severe socioeconomic consequences. METH users develop tolerance, lose control over drug taking behaviors, and suffer frequent relapses even during treatment. The clinical course of METH use disorder is influenced by multifactorial METH-induced effects on the central and peripheral nervous systems. Although these METH-induced consequences are observed in humans of all ages, races, and sexes, sexual dimorphism in these outcomes have been observed in both pre-clinical and clinical settings. In this review, we have provided a detailed presentation of the sex differences reported in human and animal studies. We have therefore presented data that identified the influences of sex on METH pharmacokinetics, METH-induced changes in behaviors, cognitive processes, structural changes in the brain, and the effects of the drug on neurotransmitter systems and molecular mechanisms. Finally, we highlighted the potential significance of sex as a critical variable that should be considered when planning the development of new pharmacotherapeutic approaches against MEH use disorder in humans.

Use of illicit amphetamines is associated with long-lasting changes in hand circuitry and control

OBJECTIVE

The study aim was to determine if use of illicit amphetamines or ecstasy is associated with abnormal excitability of the corticomotoneuronal pathway and manipulation of novel objects with the hand.

METHODS

Three groups of adults aged 18-50 years were investigated: individuals with a history of illicit amphetamine use, individuals with a history of ecstasy use but minimal use of other stimulants, and non-drug users. Transcranial magnetic stimulation was delivered to the motor cortex and the electromyographic response (motor evoked potential; MEP) was recorded from a contralateral hand muscle. Participants also gripped and lifted a novel experimental object consisting of two strain gauges and an accelerometer.

RESULTS

Resting MEP amplitude was larger in the amphetamine group (6M, 6F) than the non-drug and ecstasy groups (p < 0.005) in males but not females. Overestimation of grip force during manipulation of a novel object was observed in the amphetamine group (p = 0.020) but not the ecstasy group.

CONCLUSIONS

History of illicit amphetamine use, in particular methamphetamine, is associated with abnormal motor cortical and/or corticomotoneuronal excitability in males and abnormal manipulation of novel objects in both males and females.

SIGNIFICANCE

Abnormal excitability and hand function is evident months to years after cessation of illicit amphetamine use.

Defining the place of habit in substance use disorders

It has long been suggested that alcohol or substance use disorders could emerge from the progressive development and dominance of drug habits. Like habits, drug-related behaviors are often triggered by drug-associated cues. Like habits, addictive behaviors are strong, rigid and "hard to break". Like habits, these behaviors are insensitive to their outcome and persist despite negative consequences. "Pathological habit" thus appears as a good candidate to explain the transition to compulsive drug use. However, drug use could also be considered as a goal-directed choice, driven by the expectation of drug outcomes. For example, drug addicts may engage in drug-seeking behaviors because they view the drug as more valuable than available alternatives. Substance use disorders therefore may not be all about habit, nor fully intentional, and could be considered as resulting from an imbalance between goal-directed and habitual control. The main objective of this review is to disentangle the relative contribution of habit formation and impairment of goal-directed behavior in this unbalanced control of addictive behaviors. Although deficits in goal-directed behavior have been demonstrated in alcohol and substance use disorders, reliable demonstration of abnormal habit formation has been curtailed by the paucity of paradigms designed to assess habit as a positive result. Refining our animal and human model of habit is therefore required to precisely define the place of habit in substance use disorders and develop appropriate and adapted neurobehavioral treatments.

Sex Differences in Methamphetamine Use and Dependence in a Thai Treatment Center

BACKGROUND AND OBJECTIVE

Males and females who use methamphetamine (MA) differ in sociodemographics, MA diagnoses, comorbidities, and brain activity. The objective of this study was to investigate sex differences in the characteristics of MA use and dependence in patients at a Thai substance treatment center.

METHODS

Demographic, MA use, and diagnostic data for 782 MA users were obtained by using the Semi-Structured Assessment for Drug Dependence and Alcoholism-Thai version. Categorical comparisons of males (n = 413, 53%) and females (n = 369, 47%) were made by chi-square test. Factors significantly differentiating men and women with respect to MA-dependence were identified by logistic regression analysis controlling for demographic, diagnostic, and MA use variables.

RESULTS

Males admitted to residential drug treatment for MA use had an earlier age of onset for both MA use (17.7 ± 4.1 vs 19.7 ± 6.2 years; t = -5.3, P < 0.001) and dependence (20.4 ± 5.2 vs 22.2 ± 6.4 years; t = -3.6, P < 0.001). Females were more likely than males to be MA-dependent (79% vs 60%; χ1 = 33.7, P < 0.001), and to experience MA withdrawal (65.3% vs 48.9%; χ1 = 21.4, P < 0.001), withdrawal-related hypersomnia (77.2% vs 64.8%; χ1 = 14.5, P < 0.001), fatigue (77.5% vs 70.3%; χ1 = 5.2, P = 0.02), and psychomotor retardation (64.5% vs 57.0%; χ1 = 4.5, P = 0.03). Similarly, females had heavier (eg, largest daily amount [χ1 = 12.4, P < 0.001), more frequent (χ1 = 5.1, P = 0.02]) and greater lifetime episodes of MA use (χ1 = 24.1, P < 0.001) than males. After controlling for such variables by logistic regression, being female remained a significant factor influencing the occurrence of MA-dependence (odds ratio [OR] 2.7, 95% confidence interval [CI] 1.8-4.1, P < 0.001). Shared associated factors (or comorbidities) for MA-dependence in both sexes included nicotine dependence (in males: OR 4.1, 95% CI 2.4-7.0, P < 0.001; and in females: OR 2.4, 95% CI 1.3-4.4, P = 0.007), greater lifetime episodes of MA use (in males: OR 3.5, 95% CI 1.9-6.4, P < 0.001; and in females: OR 5.9, 95% CI 3.1-11.4, P < 0.001), and more frequent use (in males: OR 5.1, 95% CI 2.8-9.1, P < 0.001; and in females: OR 3.6, 95% CI 1.9-6.9, P < 0.001). Comorbid antisocial personality disorder predicted MA-dependence in males only (OR 3.7, 95% CI 1.6-8.6, P = 0.002).

CONCLUSIONS

The current study highlights both common (eg, nicotine dependence and severity of MA use) and sex-specific differences (eg, MA use/dependence characteristics and comorbidities), including sex itself, with respect to MA-dependence in a Thai treatment cohort.

Methamphetamine-induced toxic leukoencephalopathy: clinical, radiological and autopsy findings

Toxic leukoencephalopathy represents a process of structural alteration of the white matter. It is caused by substance abuse including drugs such as heroin, cocaine, toluene and ethanol. We reported the clinical, radiological and autopsy findings of a rare case of toxic leukoencephalopathy following chronic methamphetamine (MA) usage. A 34-year-old man with a 3-year history of MA abuse experienced progressive sluggish state, limb weakness, inability to stand and eating disorders, followed by rapid progression to coma and death. Imaging revealed hypodense CT and long T1 and T2 signals in MRI in the white matter of the bilateral periventricular and centrum semiovale regions. Histologically, white matter rarefaction, loss of myelin and axonal injury were observed. This pattern of clinical presentation, radiological manifestations and histological findings show a certain degree of particularity in toxic leukoencephalopathy. Clinically, the condition may be easily misdiagnosed as withdrawal symptoms. In suspected cases, MRI is recommended for diagnosis. The case reported here reminds clinicians and forensic pathologist of the possibility of toxic leukoencephalopathy related to MA abuse.

Deep grey matter iron accumulation in alcohol use disorder

PURPOSE

Evaluate brain iron accumulation in alcohol use disorder (AUD) patients compared to controls using quantitative susceptibility mapping (QSM).

METHODS

QSM was performed retrospectively by using phase images from resting state functional magnetic resonance imaging (fMRI). 20 male AUD patients and 15 matched healthy controls were examined. Susceptibility values were manually traced in deep grey matter regions including caudate nucleus, combined putamen and globus pallidus, combined substantia nigra and red nucleus, dentate nucleus, and a reference white matter region in the internal capsule. Average susceptibility values from each region were compared between the patients and controls. The relationship between age and susceptibility was also explored.

RESULTS

The AUD group exhibited increased susceptibility in caudate nucleus (+8.5%, p=0.034), combined putamen and globus pallidus (+10.8%, p=0.006), and dentate nucleus (+14.9%, p=0.022). Susceptibility increased with age in two of the four measured regions - combined putamen and globus pallidus (p=0.013) and combined substantia nigra and red nucleus (p=0.041). AUD did not significantly modulate the rate of susceptibility increase with age in our data.

CONCLUSION

Retrospective QSM computed from standard fMRI datasets provides new opportunities for brain iron studies in psychiatry. Substantially elevated brain iron was found in AUD subjects in the basal ganglia and dentate nucleus. This was the first human AUD brain iron study and the first retrospective clinical fMRI QSM study.

The neurocircuitry involved in oxytocin modulation of methamphetamine addiction

The role of oxytocin in attenuating the abuse of licit and illicit drugs, including the psychostimulant methamphetamine, has been examined with increased ferocity in recent years. This is largely driven by the potential application of oxytocin as a pharmacotherapy. However, the neural mechanisms by which oxytocin modulates methamphetamine abuse are not well understood. Recent research identified an important role for the accumbens core and subthalamic nucleus in this process, which likely involves an interaction with dopamine, glutamate, GABA, and vasopressin. In addition to providing an overview of methamphetamine, the endogenous oxytocin system, and the effects of exogenous oxytocin on drug abuse, we propose a neural circuit through which exogenous oxytocin modulates methamphetamine abuse, focusing on its interaction with neurochemicals within the accumbens core and subthalamic nucleus. A growing understanding of exogenous oxytocin effects at a neurochemical and neurobiological level will assist in its evaluation as a pharmacotherapy for drug addiction.

Methamphetamine addiction: involvement of CREB and neuroinflammatory signaling pathways

RATIONALE AND OBJECTIVES

Addiction to psychostimulant methamphetamine (METH) remains a major public health problem in the world. Animal models that use METH self-administration incorporate many features of human drug-taking behavior and are very helpful in elucidating mechanisms underlying METH addiction. These models are also helping to decipher the neurobiological substrates of associated neuropsychiatric complications. This review summarizes our work on the influence of METH self-administration on dopamine systems, transcription and immune responses in the brain.

METHODS

We used the rat model of METH self-administration with extended access (15 h/day for eight consecutive days) to investigate the effects of voluntary METH intake on the markers of dopamine system integrity and changes in gene expression observed in the brain at 2 h-1 month after cessation of drug exposure.

RESULTS

Extended access to METH self-administration caused changes in the rat brain that are consistent with clinical findings reported in neuroimaging and postmortem studies of human METH addicts. In addition, gene expression studies using striatal tissues from METH self-administering rats revealed increased expression of genes involved in cAMP response element binding protein (CREB) signaling pathway and in the activation of neuroinflammatory response in the brain.

CONCLUSION

These data show an association of METH exposure with activation of neuroplastic and neuroinflammatory cascades in the brain. The neuroplastic changes may be involved in promoting METH addiction. Neuroinflammatory processes in the striatum may underlie cognitive deficits, depression, and parkinsonism reported in METH addicts. Therapeutic approaches that include suppression of neuroinflammation may be beneficial to addicted patients.

Lifetime methamphetamine dependence is associated with cerebral microgliosis in HIV-1-infected adults

Methamphetamine (Meth) use is common among HIV-infected persons. It remains unclear whether Meth dependence is associated with long-lasting degenerative changes in the brain parenchyma and microvasculature of HIV-infected individuals. We examined the postmortem brains of 78 HIV-infected adults, twenty of whom were diagnosed with lifetime Meth dependence (18 past and two current at the final follow-up visit). Using logistic regression models, we analyzed associations of Meth with cerebral gliosis (immunohistochemistry for ionized calcium-binding adapter molecule-1 (Iba1) and glial fibrillary acidic protein (GFAP) in frontal, temporo-parietal, and putamen-internal capsule regions), synaptodendritic loss (confocal microscopy for synaptophysin (SYP) and microtubule-associated protein-2 (MAP2) in frontal cortex), β-amyloid plaque deposition (immunohistochemistry in frontal and temporo-parietal cortex and putamen), and arteriolosclerosis (histopathology in forebrain white matter). We found that Meth was associated with marked Iba1 gliosis in the temporo-parietal region (odds ratio, 4.42 (95 % confidence interval, 1.36, 14.39), p = 0.014, n = 62), which remained statistically significant after adjusting for HIV encephalitis, white matter lesions, and opportunistic diseases (n = 61); hepatitis C virus seropositivity (n = 54); and lifetime dependence on alcohol, opiates, and cannabis (n = 62). There was no significant association of Meth with GFAP gliosis, SYP or MAP2 loss, β-amyloid plaque deposition, or arteriolosclerosis. In conclusion, we found lifetime Meth dependence to be associated with focal cerebral microgliosis among HIV-infected adults, but not with other brain degenerative changes examined. Some of the changes in select brain regions might be reversible following extended Meth abstinence or, alternatively, might have not been induced by Meth initially.

An Update of the Review of Neuropsychological Consequences of HIV and Substance Abuse: A Literature Review and Implications for Treatment and Future Research

Neuropyschological dysfunction, ranging from mild cerebral indicators to dementia has been a consistent part of the medical picture of HIV/AIDS. However, advances in medical supervision, particularly as a result of antiretroviral (ARV) treatment, have resulted in some mitigation of the neuropsychological effects of HIV and necessitate re-evaluation of the pattern and nature of HIV-related cognitive or mental deficits. The associated enhancements in morbidity and mortality that have occurred as a result of ARV medication have led to a need for interventions and programs that maintain behaviors that are healthy and stop the resurgence of the risk of HIV transmission. Risk factors such as mental illness and substance use that may have contributed to the initial infection with HIV still need consideration. These risk factors may also increase neuropsychological dysfunction and impact observance of prevention for treatment and recommendations. Explicitly, a better comprehension of the role of substance use on the progression of HIV-related mental decline can enlighten management and evaluation of persons living with HIV with concurrent disorders of substance use. This review provides a summary of the neurophyschology of substance use and HIV and the existing research that has looked at the effects of both substance use and HIV disease on neurophyscological function and suggestions for future research and treatment.

The impact of periventricular white matter lesions in patients with bipolar disorder type I

INTRODUCTION

White matter hyperintensities (WMHs) are one the most common neuroimaging findings in patients with bipolar disorder (BD). It has been suggested that WMHs are associated with impaired insight in schizophrenia and schizoaffective patients; however, the relationship between insight and WMHs in BD type I has not been directly investigated.

METHODS

Patients with BD-I (148) were recruited and underwent brain magnetic resonance imaging (MRI). Affective symptoms were assessed using Young Mania Rating Scale (YMRS) and Hamilton Depression Rating Scale (HDRS17); the presence of impaired insight was based on the corresponding items of YMRS and HDRS17.

RESULTS

Multiple punctate periventricular WMHs (PWMHs) and deep WMHs (DWMHs) were observed in 49.3% and 39.9% of the cases, respectively. Subjects with lower insight for mania had significantly more PWMHs (54.6% vs 22.2%; p < 0.05) when compared to BD-I patients with higher insight for mania. The presence of PWMHs was independently associated with lower insight for mania: patients who denied illness according to the YMRS were 4 times more likely to have PWMHs (95% CI: 1.21/13.42) than other patients.

CONCLUSIONS

Impaired insight in BD-I is associated with periventricular WMHs. The early identification of BD-I subjects with PWMHs and impaired insight may be crucial for clinicians.

Cerebral White Matter Lesions and Affective Episodes Correlate in Male Individuals with Bipolar Disorder

Background

Cerebral white matter lesions (WML) have been found in normal aging, vascular disease and several neuropsychiatric conditions. Correlations of WML with clinical parameters in BD have been described, but not with the number of affective episodes, illness duration, age of onset and Body Mass Index in a well characterized group of euthymic bipolar adults. Herein, we aimed to evaluate the associations between bipolar course of illness parameters and WML measured with volumetric analysis.

Methods

In a cross-sectional study 100 euthymic individuals with BD as well as 54 healthy controls (HC) were enrolled to undergo brain magnetic resonance imaging using 3T including a FLAIR sequence for volumetric assessment of WML-load using FSL-software. Additionally, clinical characteristics and psychometric measures including Structured Clinical Interview according to DSM-IV, Hamilton-Depression, Young Mania Rating Scale and Beck’s Depression Inventory were evaluated.

Results

Individuals with BD had significantly more (F = 3.968, p < .05) WML (Mdn = 3710mm3; IQR = 2961mm3) than HC (Mdn = 2185mm3; IQR = 1665mm3). BD men (Mdn = 4095mm3; IQR = 3295mm3) and BD women (Mdn = 3032mm3; IQR = 2816mm3) did not significantly differ as to the WML-load or the number and type of risk factors for WML. However, in men only, the number of manic/hypomanic episodes (r = 0.72; p < .001) as well as depressive episodes (r = 0.51; p < .001) correlated positively with WML-load.

Conclusions

WML-load strongly correlated with the number of manic episodes in male BD patients, suggesting that men might be more vulnerable to mania in the context of cerebral white matter changes.

Methadone use in a male with the FMRI premutation and FXTAS

The fragile X-associated tremor ataxia syndrome (FXTAS) is caused by the premutation in FMR1 gene. Recent reports of environmental toxins appear to worsen the progression of FXTAS. Here we present a case of male adult with FXTAS and a long history of methadone use. The patient shows a faster progression in both symptoms of disease and MRI changes compared to what is typically seen in FXTAS. There has been no research regarding the role of narcotics in onset, progression, and severity of FXTAS symptoms. However, research has shown that narcotics can have a negative impact on several neurodegenerative diseases, and we hypothesize that in this particular case, methadone may have contributed to a faster progression of FXTAS as well as exacerbating white matter disease through RNA toxicity seen in premutation carriers.

Investigating the microstructural and neurochemical environment within the basal ganglia of current methamphetamine abusers

BACKGROUND

Methamphetamine is a highly addictive psychostimulant and the medical, social, and economic consequences associated with its use have become a major international problem. Current evidence has shown methamphetamine to be particularly neurotoxic to dopamine neurons and striatal structures within the basal ganglia. A previous study from our laboratory demonstrated larger putamen volumes in actively using methamphetamine-dependent participants. The purpose of this current study was to determine whether striatal structures in the same sample of participants also exhibit pathology on the microstructural and molecular level.

METHODS

Diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS) were carried out in current methamphetamine users (n = 18) and healthy controls (n = 22) to investigate diffusion indices and neurometabolite levels in the basal ganglia.

RESULTS

Contrary to findings from previous DTI and MRS studies, no significant differences in diffusion indices or metabolite levels were observed in the basal ganglia regions of current methamphetamine users.

CONCLUSIONS

These findings differ from those reported in abstinent users and the absence of diffusion and neurochemical abnormalities may suggest that striatal enlargement in current methamphetamine use may be due to mechanisms other than edema and glial proliferation.

Structural, functional and spectroscopic MRI studies of methamphetamine addiction

This chapter reviews selected neuroimaging findings related to long-term amphetamine and methamphetamine (MA) use. An overview of structural and functional (fMRI) MR studies, Diffusion Tensor Imaging (DTI), Magnetic Resonance Spectroscopy (MRS) and Positron Emission Tomography (PET) studies conducted in long-term MA abusers is presented. The focus of this chapter is to present the relevant studies as tools to understand brain changes following drug abstinence and recovery from addiction. The behavioral relevance of these neuroimaging studies is discussed as they relate to clinical symptoms and treatment. Within each imaging section this chapter includes a discussion of the relevant imaging studies as they relate to patterns of drug use (i.e., duration of MA use, cumulative lifetime dose and time MA abstinent) as well as an overview of studies that link the imaging findings to cognitive measures. In our conclusion we discuss some of the future directions of neuroimaging as it relates to the pathophysiology of addiction.

Comparison of brain white matter hyperintensities in methamphetamine and methadone dependent patients and healthy controls

Background:

Previous studies have proven the development of white matter hyperintensities (WMH) in methamphetamine and opioid users. Opiates and methamphetamines (MA) are the most common addictive agents in Iran. The adverse effects of drugs on the CNS is of concern to specialists and researchers, and given that the neurotoxicity associated with methamphetamine is greater than opioids, it is hypothesized that the severity of WMH in patients with methamphetamine dependence is more than opioid drug-dependent individuals.

Objectives:

To our knowledge, this is the first research comparing the effect of methamphetamine and methadone (M) on the brain.

Patients and Methods:

In a historical cohort study, we compared WMH in the brain MRI of 50 methamphetamine-dependent patients, 50 methadone-dependent patients and 50 healthy volunteers who were matched for age, sex and dominant hand.

Results:

WMH was detected in 18 methamphetamine users, in 12 methadone users and in seven controls (P = 0.038). The site of brain lesions in MA users was mostly in the frontal lobe in 17 cases, in M users in the frontal lobe in 12 cases and in the control group, it was in the parietal lobe in four cases (P=0.001). The frontal lobes were the predominant locations of WMH in MA and M groups (P = 0.001). The frequency of brain lesions was mostly in the deep WM in 18 cases in MA users, in 12 cases in M users and in two cases in the control group (P=0.007). Hyper-signal foci of deep WM in the MA group were grade I (punctuate) in 12 cases, grade II (beginning confluence) in five cases and grade III (large confluent) in four cases. In the M group, there were six cases in grade I, three cases in grade II and one case in grade III. In the control group, there were three grade I cases, two grade II cases, and no grade III cases. Except for periventricular WMH (P = 0.13), there were statistical significant differences in the deep WMH (P = 0.007) and subcortex WMH (P = 0.01) between the three groups. The history of using other drugs and the duration of MA and M consumption were similar. The prevalence of brain lesions was generally higher in both drug user groups compared with the healthy controls. Increased WMH in the MA group was higher than the M group.

Conclusions:

A greater number of blood flow defects and ischemic lesions in the brain of MA users compared to opiate users may explain the prevalence of psychiatric disorders in these patients.

Frontal white matter alterations are associated with executive cognitive function in euthymic bipolar patients

BACKGROUND

Bipolar affective disorder (BD) is often associated with cognitive dysfunction in executive domains. However the biological underpinnings of cognitive deficits in BD are not sufficiently understood. A growing body of evidence indicates a loss of microstructural integrity in various white matter (WM) fiber tracts in BD. The aim of the current study was to assess potential links between WM structural abnormalities and cognitive performance in euthymic middle-aged BD patients (n=30) and matched healthy controls (n=32).

METHODS

Diffusion tensor imaging (DTI) data was carried out with both voxelwise (tract based spatial statistics, TBSS) and region-of-interest (ROI) based analysis. We compared multiple indices of diffusion including fractional anisotropy (FA), radial (DR), axial (DA) and mean diffusivities (MD).

RESULTS

Increased mean diffusivity was found in the fornix, anterior thalamic radiation, splenium and the truncus of the corpus callosum in BD patients compared with controls. These diffusion changes were significantly associated with poorer performance in executive tasks in BD patients.

CONCLUSIONS

Our results indicate a direct link between executive cognitive functioning and abnormal WM microstructural integrity of fronto-limbic tracts in remitted BD patients, and add evidence to the neuronal disruption that underlies the residual symptomatology of BD.

The effects of methylphenidate on cognitive control in active methamphetamine dependence using functional magnetic resonance imaging

Methamphetamine (MA) dependence is associated with cognitive deficits. Methylphenidate (MPH) has been shown to improve inhibitory control in healthy and cocaine-dependent subjects. This study aimed to understand the neurophysiological effects before and after acute MPH administration in active MA-dependent and control subjects. Fifteen MA-dependent and 18 control subjects aged 18-46 years were scanned using functional magnetic resonance imaging before and after either a single oral dose of MPH (18 mg) or placebo while performing a color-word Stroop task. Baseline accuracy was lower (p = 0.026) and response time (RT) was longer (p < 0.0001) for the incongruent compared to congruent condition, demonstrating the task probed cognitive control. Increased activation of the dorsolateral prefrontal cortex (DLPFC) and parietal cortex during the incongruent and Stroop effect conditions, respectively was observed in MA-dependent compared to control subjects (p < 0.05), suggesting the need to recruit neural resources within these regions for conflict resolution. Post- compared to pre-MPH treatment, increased RT and DLPFC activation for the Stroop effect were observed in MA-dependent subjects (p < 0.05). In comparison to MPH-treated controls and placebo-treated MA-dependent subjects, MPH-treated MA-dependent subjects showed decreased activation of parietal and occipital regions during the incongruent and Stroop effect conditions (p < 0.05). These findings suggest that in MA-dependent subjects, MPH facilitated increased recruitment of the DLPFC for Stroop conflict resolution, and a decreased need for recruitment of neural resources in parietal and occipital regions compared to the other groups, while maintaining a comparable level of task performance to that achieved pre-drug administration. Due to the small sample size, the results from this study are preliminary; however, they inform us about the effects of MPH on the neural correlates of cognitive control in active MA-dependent subjects.

Decreased frontal lobe phosphocreatine levels in methamphetamine users

BACKGROUND

Mitochondria-related mechanisms have been suggested to mediate methamphetamine (METH) toxicity. However, changes in brain energetics associated with high-energy phosphate metabolism have not been investigated in METH users. Phosphorus-31 ((31)P) magnetic resonance spectroscopy (MRS) was used to evaluate changes in mitochondrial high energy phosphates, including phosphocreatine (PCr) and β-nucleoside triphosphate (β-NTP, primarily ATP in brain) levels. We hypothesized that METH users would have decreased high-energy PCr levels in the frontal gray matter.

METHODS

Study participants consisted of 51 METH (age=32.8±6.7) and 23 healthy comparison (age=31.1±7.5) subjects. High-energy phosphate metabolite levels were compared between the groups and potential gender differences were explored.

RESULTS

METH users had lower ratios of PCr to total pool of exchangeable phosphate (PCr/TPP) in the frontal lobe as compared to the healthy subjects (p=.001). The lower PCr levels in METH subjects were significantly associated with lifetime amount of METH use (p=.003). A sub-analysis for gender differences revealed that female METH users, who had lower daily amounts (1.1±1.0g) of METH use than males (1.4±1.7g), had significantly lower PCr/TPP ratios than male METH users, controlling for the amount of METH use (p=.02).

CONCLUSIONS

The present findings suggest that METH compromises frontal lobe high-energy phosphate metabolism in a dose-responsive manner. Our findings also suggest that the abnormality in frontal lobe high-energy phosphate metabolism might be more prominent in female than in male METH users. This is significant as decreased PCr levels have been associated with depressive symptoms, and poor responses to antidepressant treatment have been reported in those with decreased PCr levels.

Decreased frontal N-acetylaspartate levels in adolescents concurrently using both methamphetamine and marijuana

INTRODUCTION

The potential neurochemical toxicity associated with methamphetamine (MA) or marijuana (MJ) use on the developing adolescent brain is unclear, particularly with regard to individuals with concomitant use of MA and MJ (MA+MJ). In this study, proton magnetic resonance spectroscopy (MRS) was utilized to measure in vivo brain N-acetylaspartate plus N-acetylaspartyl glutamate (tNAA, an indicator of intact neuronal integrity) levels.

METHODS

Three adolescent groups from Cape Town, South Africa completed MRS scans as well as clinical measures including a drug use history. Subjects included (1) nine MA (age=15.7±1.37), (2) eight MA+MJ (age=16.2±1.16) using adolescents and (3) ten healthy controls (age=16.8±0.62). Single voxel spectra were acquired from midfrontal gray matter using a point-resolved spectroscopy sequence (PRESS). The MRS data were post-processed in the fully automated approach for quantitation of metabolite ratios to phosphocreatine plus creatine (PCr+Cr).

RESULTS

A significant reduction in frontal tNAA/PCr+Cr ratios was seen in the MA+MJ group compared to the healthy controls (p=0.01, by 7.2%) and to the MA group (p=0.04, by 6.9%). Significant relationships were also observed between decreased tNAA/PCr+Cr ratios and drug use history of MA or MJ (total cumulative lifetime dose, age of onset, and duration of MA and MJ exposure) only in the MA+MJ group (all p<0.05).

CONCLUSIONS

These findings suggest that in adolescents, concomitant heavy MA+MJ use may contribute to altered brain metabolites in frontal gray matter. The significant associations between the abnormal tNAA/PCr+Cr ratios and the drug use history suggest that MA+MJ abuse may induce neurotoxicity in a dose-responsive manner in adolescent brain.

Partial MHC/neuroantigen peptide constructs: a potential neuroimmune-based treatment for methamphetamine addiction

Relapse rates following current methamphetamine abuse treatments are very high (∼40-60%), and the neuropsychiatric impairments (e.g., cognitive deficits, mood disorders) that arise and persist during remission from methamphetamine addiction likely contribute to these high relapse rates. Pharmacotherapeutic development of medications to treat addiction has focused on neurotransmitter systems with only limited success, and there are no Food and Drug Administration approved pharmacotherapies for methamphetamine addiction. A growing literature shows that methamphetamine alters peripheral and central immune functions and that immune factors such as cytokines, chemokines, and adhesion molecules play a role in the development and persistence of methamphetamine induced neuronal injury and neuropsychiatric impairments. The objective of this study was to evaluate the efficacy of a new immunotherapy, partial MHC/neuroantigen peptide construct (RTL551; pI-A(b)/mMOG-35-55), in treating learning and memory impairments induced by repeated methamphetamine exposure. C57BL/6J mice were exposed to two different methamphetamine treatment regimens (using repeated doses of 4 mg/kg or 10 mg/kg, s.c.). Cognitive performance was assessed using the Morris water maze and CNS cytokine levels were measured by multiplex assay. Immunotherapy with RTL551 improved the memory impairments induced by repeated methamphetamine exposure in both mouse models of chronic methamphetamine addiction. Treatment with RTL551 also attenuated the methamphetamine induced increases in hypothalamic interleukin-2 (IL-2) levels. Collectively, these initial results indicate that neuroimmune targeted therapies, and specifically RTL551, may have potential as treatments for methamphetamine-induced neuropsychiatric impairments.

Are there volumetric brain differences associated with the use of cocaine and amphetamine-type stimulants?

While a large number of studies have examined brain volume differences associated with cocaine use, much less is known about structural differences related to amphetamine-type stimulant (ATS) use. What is known about cocaine may help to interpret emerging information on the interaction of brain volume with ATS consumption. To date, volumetric studies on the two types of stimulant have focused almost exclusively on brain differences associated with chronic use. There is considerable variability in the findings between studies which may be explained in part by the wide variety of methodologies employed. Despite this variability, seven recurrent themes are worth noting: (1) loci of lower cortical volume (approximately 10% on average) are consistently reported, (2) almost all studies indicate less volume in all or parts of the frontal cortex, (3) more specifically, a core group of studies implicate the ventromedial prefrontal cortex (including the medial portion of the orbital frontal cortex) and (4) the insula, (5) an enlarged striatal volume has been repeatedly observed, (6) reports on volume differences in the hippocampus and amygdala have been equivocal, (7) evidence supporting differential interaction of brain structure with cocaine vs. ATS is scant but the volume of all or parts of the temporal cortex appear lower in a majority of studies on cocaine but not ATS. Future research should include longitudinal designs on larger sample sizes and examine other stages of exposure to psychostimulants.

Antiandrogen pretreatment alters cocaine pharmacokinetics in men

Among cocaine users, men experience more adverse brain and vascular effects than their female counterparts. This could be caused by testosterone, which may potentiate some of cocaine's effects. We examined whether antiandrogen (flutamide, FL) pretreatment alters cocaine's acute behavioral, physiologic, and pharmacokinetic effects in men with histories of occasional cocaine use. Participants (N = 8) were pretreated with oral FL (250 mg) and placebo on separate study days followed by intravenous (IV) cocaine (0.4 mg/kg). Vital signs, subjective ratings, and blood samples for cocaine and metabolites were obtained at baseline and for 90 minutes after cocaine administration. FL, itself, had no effects on physiologic or subjective responses; however, after cocaine, heart rate recovered faster with FL pretreatment. Flutamide reduced peak plasma cocaine levels (Wilcoxon signed-rank z = 2.1, P < 0.04) and area under the curve (AUC; z = 1.96, P < 0.05). Additionally, FL reduced EME levels (z = 1.96, P < 0.05) and AUC for BE and EME (z = 2.38, P < 0.02 and z = 1.96, P < 0.05, respectively). These results suggest that FL may alter cocaine pharmacokinetics in men. Because cocaine and BE are vasoconstrictive, the data imply that FL might reduce some of cocaine's cardiovascular effects.

Functional and structural brain changes associated with methamphetamine abuse

Methamphetamine (MA) is a potent psychostimulant drug whose abuse has become a global epidemic in recent years. Firstly, this review article briefly discusses the epidemiology and clinical pharmacology of methamphetamine dependence. Secondly, the article reviews relevant animal literature modeling methamphetamine dependence and discusses possible mechanisms of methamphetamine-induced neurotoxicity. Thirdly, it provides a critical review of functional and structural neuroimaging studies in human MA abusers; including positron emission tomography (PET) and functional and structural magnetic resonance imaging (MRI). The effect of abstinence from methamphetamine, both short- and long-term within the context of these studies is also reviewed.

Abnormal behaviors and microstructural changes in white matter of juvenile mice repeatedly exposed to amphetamine

Amphetamine (AMP) is an addictive CNS stimulant and has been commonly abused by adolescents and young adults, during which period brain white matter is still developing. This study was to examine the effect of a nonneurotoxic AMP on the white matter of juvenile mice. d-AMP (1.0 mg/kg) was given to young male C57BL/6 mice once a day for 21 days. The spatial working memory and locomotion of mice were measured at the end. Then, mice were sacrificed and their brains were processed for morphological analyses to examine the white matter structure and for Western blot analysis to measure three main proteins expressed in mature oligodendrocytes. AMP-treated mice displayed higher locomotion and spatial working memory impairment and showed lower levels of Nogo-A and GST-pi proteins in frontal cortex and lower MBP protein in the frontal cortex and hippocampus. They also had fewer mature oligodendrocytes and weak MBP immunofluorescent staining in the same two brain regions. But the striatum was spared. These results suggest that the late-developing white matter is vulnerable to AMP treatment which is able to increase striatal and cortical dopamine. Both the compromised white matter and increased dopamine may contribute to the observed behavioral changes in AMP-treated mice.

Brain abnormalities detected on magnetic resonance imaging of amphetamine users presenting to an emergency department: a pilot study

OBJECTIVES

To determine the prevalence of occult brain abnormalities in magnetic resonance imaging of active amphetamine users.

DESIGN, SETTING AND PARTICIPANTS

Prospective convenience study in a tertiary hospital emergency department (ED). Patients presenting to the ED for an amphetamine-related reason were eligible for inclusion. We collected demographic data, drug use data, and performed a mini-mental state examination (MMSE).

MAIN OUTCOME MEASURES

The proportion of patients with an abnormality on their MRI scan.

RESULTS

Of 38 patients enrolled, 30 had MRI scans. Nineteen were male and their mean age was 26.7 +/- 5.4 years (range 19-41 years). The mean age of first amphetamine use was 18 years (range 13-26 years). Sixteen patients used crystal methamphetamine (mean amount 2.5 g/week), nine used amphetamine ("speed") (mean amount 2.9 g/week), and 23 used ecstasy (mean amount 2.3 tablets/week). Marijuana was smoked by 26 (mean amount 5.9 g/week), and 28 drank alcohol (mean amount 207 g/week). The median MMSE score was 27/30 (interquartile range, 26-29). Abnormalities on brain MRI scans were identified in six patients, most commonly an unidentified bright object (n = 4).

CONCLUSION

In this pilot study of brain MRI of young people attending the ED with an amphetamine-related presentation, one in five had an occult brain lesion. While the significance of this is uncertain, it is congruent with evidence that amphetamines cause brain injury.

Increased prevalence of white matter hyperintensities in patients with panic disorder

The aim of the current study is to compare the prevalence, severity and location of cerebral white matter hyperintensities (WMH) between patients with panic disorder (PD) and healthy control subjects. Patients with PD (n = 24) and matched healthy control subjects (n = 24) were scanned using a 3.0 Tesla whole-body magnetic resonance scanner. Axial T2-weighted and fluid-attenuated inversion recovery images were acquired and evaluated for the prevalence, severity and location of WMH using the modified composite scale of Fazekas and Coffey and coded separately for deep and periventricular WMH. Logistic regression analyses were used to assess the association between WMH and the diagnosis of PD. A greater severity of total WMH was associated with a diagnosis of PD in a dose-dependent pattern (odds ratio [OR] = 8.8, P = 0.005 for mild WMH; OR = 27.7, P = 0.007 for moderate to severe WMH). Deep WMH, where most group differences originated, were predominantly located in the frontal region of the brain (n = 16 in PD, n = 1 in control). The current report is the first study to report an increased prevalence of WMH in patients with PD.

Neurochemical alterations in methamphetamine-dependent patients treated with cytidine-5'-diphosphate choline: a longitudinal proton magnetic resonance spectroscopy study

Cytidine-5'-diphosphate choline (CDP-choline), as an important intermediate for major membrane phospholipids, may exert neuroprotective effects in various neurodegenerative disorders. This longitudinal proton magnetic resonance spectroscopy ((1)H-MRS) study aimed to examine whether a 4-week CDP-choline treatment could alter neurometabolite levels in patients with methamphetamine (MA) dependence and to investigate whether changes in neurometabolite levels would be associated with MA use. We hypothesized that the prefrontal levels of N-acetyl-aspartate (NAA), a neuronal marker, and choline-containing compound (Cho), which are related to membrane turnover, would increase with CDP-choline treatment in MA-dependent patients. We further hypothesized that this increase would correlate with the total number of negative urine results. Thirty-one treatment seekers with MA dependence were randomly assigned to receive CDP-choline (n=16) or placebo (n=15) for 4 weeks. Prefrontal NAA and Cho levels were examined using (1)H-MRS before medication, and at 2 and 4 weeks after treatment. Generalized estimating equation regression analyses showed that the rate of change in prefrontal NAA (p=0.005) and Cho (p=0.03) levels were greater with CDP-choline treatment than with placebo. In the CDP-choline-treated patients, changes in prefrontal NAA levels were positively associated with the total number of negative urine results (p=0.03). Changes in the prefrontal Cho levels, however, were not associated with the total number of negative urine results. These preliminary findings suggest that CDP-choline treatment may exert potential neuroprotective effects directly or indirectly because of reductions in drug use by the MA-dependent patients. Further studies with a larger sample size of MA-dependent patients are warranted to confirm a long-term efficacy of CDP-choline in neuroprotection and abstinence.

White-matter abnormalities in brain during early abstinence from methamphetamine abuse

BACKGROUND

Previous studies revealed microstructural abnormalities in prefrontal white matter and corpus callosum of long-term abstinent chronic methamphetamine abusers. In view of the importance of the early abstinence period in treatment retention, we compared 23 methamphetamine-dependent subjects abstinent from methamphetamine for 7-13 days with 18 healthy comparison subjects. As certain metabolic changes in the brain first manifest after early abstinence from methamphetamine, it is also possible that microstructural white-matter abnormalities are not yet present during early abstinence.

METHODS

Using diffusion tensor imaging at 1.5 T, fractional anisotropy (FA) was measured in prefrontal white matter at four inferior-superior levels parallel to the anterior commissure-posterior commissure (AC-PC) plane. We also sampled FA in the corpus callosum at the midline and at eight bilateral, fiber-tract sites in other regions implicated in effects of methamphetamine.

RESULTS

The methamphetamine group exhibited lower FA in right prefrontal white matter above the AC-PC plane (11.9% lower; p = 0.007), in midline genu corpus callosum (3.9%; p = 0.019), in left and right midcaudal superior corona radiata (11.0% in both hemispheres, p's = 0.020 and 0.016, respectively), and in right perforant fibers (7.3%; p = 0.025). FA in left midcaudal superior corona radiata was correlated with depressive and generalized psychiatric symptoms within the methamphetamine group.

CONCLUSIONS

The findings support the idea that methamphetamine abuse produces microstructural abnormalities in white matter underlying and interconnecting prefrontal cortices and hippocampal formation. These effects are already present during the first weeks of abstinence from methamphetamine and are linked to psychiatric symptoms assessed during this period.

Higher diffusion in striatum and lower fractional anisotropy in white matter of methamphetamine users

Methamphetamine (METH) users showed structural and chemical abnormalities on magnetic resonance (MRI) studies, particularly in the frontal and basal ganglia brain regions. Diffusion tensor imaging (DTI) may provide further insights regarding the microstructural changes in METH users. We investigated diffusion tensor measures in frontal white matter and basal ganglia of 30 adult METH users and 30 control subjects using a 3 T MR scanner. Compared with healthy control subjects, METH users showed lower fractional anisotropy (FA) in right frontal white matter, and higher apparent diffusion coefficient (ADC) in left caudate and bilateral putamen. Higher left putamen ADC was associated with earlier initiation of METH use, greater daily amounts, and a higher cumulative lifetime dose. Similarly, higher right putamen ADC was associated with greater daily amounts and a higher cumulative lifetime dose. The lower FA in the right frontal white matter suggests axonal injury in these METH users. The higher ADC in the basal ganglia suggests greater inflammation or less myelination in these brain regions of those with younger age of first METH use and greater METH usage.

Addictive illegal drugs: structural neuroimaging

Illegal addictive drugs can lead to functional or structural impairment of the central nervous system. This review provides an overview of the structural imaging findings on CT, MR imaging, and conventional angiography related to chronic and acute abuse of the most commonly abused illegal drugs, including cannabis, organic solvents, and amphetamines and opioids and their respective derivatives. Pathomechanisms include excitotoxicity, which may lead to an acute or subacute leukoencephalopathy, and vascular complications, including vasoconstriction, vasculitis, or hypertension, which may lead to intracranial hemorrhage or ischemia. Because clinical findings alone are often nonspecific, and afflicted patients are unlikely to admit to the substance abuse, the neuroradiologist may play an important role in establishing the diagnosis and, thereby, initiating treatment.

Dose-dependent frontal hypometabolism on FDG-PET in methamphetamine abusers

OBJECTIVE

Although a lot of evidence from neuropsychological and neuroimaging studies supports the view that patients with substance dependence have abnormalities in the prefrontal cortex, functional deficits in the prefrontal cortex have not been fully investigated in methamphetamine (MA) dependent patients. This study was prepared to examine whether MA abusers have cerebral metabolic abnormalities and executive dysfunction.

METHOD

Twenty-four abstinent MA dependent patients and 21 age-matched control subjects underwent resting brain FDG-PET and completed computerized versions of the Wisconsin card sorting test (WCST). Resting brain PET images were obtained 30min after an intravenous injection of 370MBq of (18)F-FDG. Significant differences in glucose metabolism were estimated for every voxel using t-statistics on SPM2 implemented in Matlab.

RESULTS

Resting brain FDG-PET revealed significant hypometabolism in the left inferior frontal white matter (Talairach coordinates (x, y, z): -34, 7, 31) in MA dependent patients compared to the control subjects (corrected p=0.001, peak Z=5.37, voxel number 201). The nearest gray matter region was the left inferior frontal cortex (Brodmann area 9). There were negative correlations between the relative regional cerebral metabolism for glucose (rCMRglc) in the left inferior frontal white matter and the total cumulative dose of MA (r=-0.57, p<0.01). MA dependent patients completed significantly fewer categories (3.8+/-2.2) and made more perseveration errors (21.3+/-11.8) and total errors (43.5+/-19.5) on the WCST when compared to the control subjects (p<0.01).

CONCLUSIONS

These data suggest that MA dependent patients have dose-dependent frontal hypometabolism and frontal executive dysfunction.

White matter hyperintensities in the forties: their prevalence and topography in an epidemiological sample aged 44-48

White matter hyperintensities (WMHs) are a frequent finding on T2-weighted MRI of the brain in elderly individuals, but their prevalence and severity in younger asymptomatic populations is less well studied. We report the topography of WMHs on T2-weighted fluid inversion recovery (FLAIR) MRI in 428 individuals aged 44-48 years recruited randomly from a healthy community sample. WMHs were delineated from FLAIR and T1-weighted scans by using a computer algorithm, further verified and then classified using k-nearest neighbor (kNN) algorithm into deep WMH (DWMH), and periventricular WMH (PVWMH), which included extended periventricular "rims" and frontal and occipital "caps". Small caps and pencil-thin rims were not taken as WMHs for this analysis. The new computer algorithm was validated and compared with the scores of visual rating, and the correspondence between the two methods was high. We found that 218 (50.9%) subjects had WMHs. 146 of the 218 (34.1% of whole sample population of 428) subjects had deep white matter hyperintensities (DWMHs). The average number of WMH clusters (occurrences) per brain was 1.37 (0.94 for DWMH and 0.43 for pathological PVWMH) and the mean WMH tissue volume was 0.278 ml. There was no significant sex difference in the severity and distribution of WMHs. The study suggests that small punctate or focal WMHs are common in the brains of individuals in their 40s, and may represent an early stage of development of these lesions.

Valproate activates the Notch3/c-FLIP signaling cascade: a strategy to attenuate white matter hyperintensities in bipolar disorder in late life?

OBJECTIVES

Increased prevalence of deep white matter hyperintensities (DWMHs) has been consistently observed in patients with geriatric depression and bipolar disorder. DMWHs are associated with chronicity, disability, and poor quality of life. They are thought to be ischemic in their etiology and may be related to the underlying pathophysiology of mood disorders in the elderly. Notably, these lesions strikingly resemble radiological findings related to the cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephelopathy (CADASIL) syndrome. CADASIL arises from mutations in Notch3, resulting in impaired signaling via cellular Fas-associated death domain-like interleukin-1-beta-converting enzyme-inhibitory protein (c-FLIP) through an extracellular signal-regulated kinase (ERK)-dependent pathway. These signaling abnormalities have been postulated to underlie the progressive degeneration of vascular smooth muscle cells (VSMC). This study investigates the possibility that the anticonvulsant valproate (VPA), which robustly activates the ERK mitogen-activated protein kinase (MAPK) cascade, may exert cytoprotective effects on VSMC through the Notch3/c-FLIP pathway.

METHODS

Human VSMC were treated with therapeutic concentrations of VPA subchronically. c-FLIP was knocked down via small interfering ribonucleic acid transfection. Cell survival, apoptosis, and protein levels were measured.

RESULTS

VPA increased c-FLIP levels dose- and time-dependently and promoted VSMC survival in response to Fas ligand-induced apoptosis in VSMC. The anti-apoptotic effect of VPA was abolished by c-FLIP knockdown. VPA also produced similar in vivo effects in rat brain.

CONCLUSIONS

These results raise the intriguing possibility that VPA may be a novel therapeutic agent for the treatment of CADASIL and related disorders. They also suggest that VPA might decrease the liability of patients with late-life mood disorders to develop DWMHs.

Methamphetamine toxicity and messengers of death

Methamphetamine (METH) is an illicit psychostimulant that is widely abused in the world. Several lines of evidence suggest that chronic METH abuse leads to neurodegenerative changes in the human brain. These include damage to dopamine and serotonin axons, loss of gray matter accompanied by hypertrophy of the white matter and microgliosis in different brain areas. In the present review, we summarize data on the animal models of METH neurotoxicity which include degeneration of monoaminergic terminals and neuronal apoptosis. In addition, we discuss molecular and cellular bases of METH-induced neuropathologies. The accumulated evidence indicates that multiple events, including oxidative stress, excitotoxicity, hyperthermia, neuroinflammatory responses, mitochondrial dysfunction, and endoplasmic reticulum stress converge to mediate METH-induced terminal degeneration and neuronal apoptosis. When taken together, these findings suggest that pharmacological strategies geared towards the prevention and treatment of the deleterious effects of this drug will need to attack the various pathways that form the substrates of METH toxicity.

Cognitive control and white matter callosal microstructure in methamphetamine-dependent subjects: a diffusion tensor imaging study

BACKGROUND

Methamphetamine (MA) abuse causes damage to structures within the human cerebrum, with particular susceptibility to white matter (WM). Abnormalities have been reported in anterior regions with less evidence of changes in posterior regions. Methamphetamine abusers have also shown deficits on attention tests that measure response conflict and cognitive control.

METHODS

We examined cognitive control with a computerized measure of the Stroop selective attention task and indices of WM microstructure obtained from diffusion tensor imaging (DTI) in the callosal genu and splenium of 37 currently abstinent MA abusers and 17 non-substance abusing control subjects. Measurements of fractional anisotropy (FA), apparent diffusion coefficient (ADC) of callosal fibers, and diffusion tensor eigenvalues were obtained in all subjects.

RESULTS

The MA abusers exhibited greater Stroop reaction time interference (i.e., reduced cognitive control) (p = .04) compared with control subjects. After correcting for multiple comparisons, FA within the genu correlated significantly with measures of cognitive control in the MA abusers (p = .04, Bonferroni corrected) but not in control subjects (p = .26). Group differences in genu but not splenium FA were trend significant (p = .09).

CONCLUSIONS

Methamphetamine abuse seems to alter anterior callosal WM microstructure with less evidence of change within posterior callosal WM microstructure. The DTI indices within the genu but not splenium correlated with measures of cognitive control in chronic MA abusers.

Abuse of amphetamines and structural abnormalities in the brain

We review evidence that structural brain abnormalities are associated with abuse of amphetamines. A brief history of amphetamine use/abuse and evidence for toxicity is followed by a summary of findings from structural magnetic resonance imaging (MRI) studies of human subjects who had abused amphetamines and children who were exposed to amphetamines in utero. Evidence comes from studies that used a variety of techniques including manual tracing, pattern matching, voxel-based, tensor-based, or cortical thickness mapping, quantification of white matter signal hyperintensities, and diffusion tensor imaging. Ten studies compared controls to individuals who were exposed to methamphetamine. Three studies assessed individuals exposed to 3-4-methylenedioxymethamphetamine (MDMA). Brain structural abnormalities were consistently reported in amphetamine abusers, as compared to control subjects. These included lower cortical gray matter volume and higher striatal volume than control subjects. These differences might reflect brain features that could predispose to substance dependence. High striatal volumes might also reflect compensation for toxicity in the dopamine-rich basal ganglia. Prenatal exposure was associated with striatal volume that was below control values, suggesting that such compensation might not occur in utero. Several forms of white matter abnormality are also common and may involve gliosis. Many of the limitations and inconsistencies in the literature relate to techniques and cross-sectional designs, which cannot infer causality. Potential confounding influences include effects of pre existing risk/protective factors, development, gender, severity of amphetamine abuse, abuse of other drugs, abstinence, and differences in lifestyle. Longitudinal designs in which multimodal datasets are acquired and are subjected to multivariate analyses would enhance our ability to provide general conclusions regarding the associations between amphetamine abuse and brain structure.

Gender differences in methamphetamine use and responses: a review

BACKGROUND

Men and women differ markedly with regard to their use of, and responses to, methamphetamine (MA) and related amphetamines. However, these gender differences oftentimes are given only a cursory consideration in the analyses of these MA effects.

OBJECTIVE

In this brief review, we summarize the data on gender differences in various parameters of MA use and responses. Such information on the pattern of male versus female differences in the use and responses to this psychostimulant can aid in tailoring gender-dependent treatment strategies.

METHODS

English-language articles were identified from MEDLINE as well as from reference lists of identified articles for the years 1966 to 2007. Search terms included various combinations of men/male, women/female, methamphetamine, and gender/sex differences. Only studies with human subjects were reviewed.

RESULTS

Women tend to begin MA use at earlier ages, appear more dependent on MA, but also respond better to treatment than do men. MA use appears to be associated with depression in women, and women seem more committed to MA, whereas men are more likely to use other drugs in the absence of access to MA. Female MA abusers had both larger volumes within the corpus callosum and more hyperperfused regions in the parietal and occipital areas of the brain, along with more genetic alterations but less MA-induced toxicity. Amphetamine-stimulated dopamine release was greater in men.

CONCLUSIONS

When considered in total, women seem more dependent on and committed to MA but show diminished (amphetamine-stimulated) dopamine responses and a decreased degree of toxicity, as indicated by a lower incidence of emergency department-related deaths involving MA. A pervasive comorbidity of depression or depression-related characteristics were present in women MA users, suggesting that MA may serve as a type of self-medication for their depression. These findings not only highlight the need for consideration of gender when assessing MA use, but also can serve to direct efforts at prevention and treatment programs that address the specific needs of men and women.

Psychoproteomic analysis of rat cortex following acute methamphetamine exposure

Methamphetamine (METH) is recognized as one of the most abused psychostimulants in the United States. METH is an illicit drug that is known to exert neurotoxic effects on both dopaminergic and serotonergic neural systems both in vivo and in vitro. Our laboratory and others have been studying the biochemical mechanisms underlying METH-induced neurotoxicity. Here, we applied a novel psychoproteomic approach to evaluate METH-induced neurotoxicity following acute METH administration (4x10 mg/kg, ip injections every 1 h). Samples of cortical tissue collected 24 h post METH treatment were pooled, processed and analyzed via a selective psychoproteomic platform. Protein separation was performed using our previously established offline tandem cation-anion exchange chromatography-SDS-1D-PAGE platform (CAX-PAGE). Gel bands exhibiting 2 or more fold changes were extracted, trypsinized and subjected to reversed-phase liquid chromatography-tandem mass spectrometry (RPLC-MS/MS) analyses for protein identification. Differential changes of the selected proteins were further confirmed by quantitative immunoblotting. We identified 82 differentially expressed proteins, 40 of which were downregulated and 42 of which were upregulated following acute METH treatment. Proteins that decreased in abundance included collapsin response mediator protein-2 (CRMP-2), superoxide dismutase 1 (SOD 1), phosphatidylethanolamine-binding protein-1 (PEBP-1) and mitogen activated kinase kinase-1 (MKK-1). Proteins that increased in abundance included authophagy-linked microtubule-associated protein light chain 3 (LC3), synapsin-1, and Parkinsonism linked ubiquitin carboxy-terminal hydroxylase-L1 (UCH-L1). Lastly, we used these differentially expressed protein subsets to construct a "psychoproteomic" spectrum map in an effort to uncover potential protein interactions relevant to acute METH neurotoxicity.

The effects of type 1 diabetes on cerebral white matter

AIM/HYPOTHESIS

Studies investigating the structure, neurophysiology and functional outcomes of white matter among type 1 diabetes patients have given conflicting results. Our aim was to investigate the relationship between type 1 diabetes and white matter hyperintensities.

METHOD

We assessed white matter integrity (using magnetic resonance imaging), depressive symptoms and neuropsychological function in 114 type 1 diabetes patients and 58 age-matched non-diabetic controls.

RESULTS

Only Fazekas grade 1 and 2 white matter hyperintensities were found among 114 long-duration, relatively young diabetes patients; the severity of lesions did not differ substantially from 58 healthy controls. White matter hyperintensities were not associated with depressive history or with clinical characteristics of diabetes, including retinopathy, severe hypoglycaemia or glycaemia control.

CONCLUSIONS/INTERPRETATION

Our data do not support an association between diabetes characteristics and white matter hyperintensities among relatively young type 1 diabetes participants.

Interactions of HIV and methamphetamine: cellular and molecular mechanisms of toxicity potentiation

Methamphetamine (METH) is a highly addictive psychostimulant drug, whose abuse has reached epidemic proportions worldwide. METH use is disproportionally represented among populations at high risks for developing HIV infection or who are already infected with the virus. Psychostimulant abuse has been reported to exacerbate the cognitive deficits and neurodegenerative abnormalities observed in HIV-positive patients. Thus, the purpose of the present paper is to review the clinical and basic observations that METH potentiates the adverse effects of HIV infection. An additional purpose is to provide a synthesis of the cellular and molecular mechanisms that might be responsible for the increased toxicity observed in co-morbid patients. The reviewed data indicate that METH and HIV proteins, including gp120, gp41, Tat, Vpr and Nef, converge on various caspase-dependent death pathways to cause neuronal apoptosis. The role of reactive microgliosis in METH- and in HIV-induced toxicity is also discussed.

Decreased frontal white-matter integrity in abstinent methamphetamine abusers

This study explored differences in frontal white-matter (WM) integrity between methamphetamine (MA) abusers and healthy comparison subjects using diffusion tensor imaging (DTI). Fractional anisotropy (FA) values, which indicate WM integrity, were calculated for regions-of-interest in frontal WM on diffusion tensor images of 32 MA abusers and 30 healthy comparison subjects. Frontal executive functions were also assessed by the Wisconsin Card Sorting test (WCST). MA abusers had significantly lower FA values in bilateral frontal WM at the anterior commissure-posterior commissure (AC-PC) plane and the right frontal WM 5 mm above the AC-PC plane relative to healthy comparison subjects. MA abusers had more total, perseveration and non-perseveration errors in the WCST relative to healthy comparison subjects. FA values of the right frontal WM 5 mm above the AC-PC plane negatively correlated with the number of total and non-perseveration errors in the WCST in MA abusers. In the sub-analysis for gender differences, lower FA values in frontal WM and more errors in the WCST were found only in male MA abusers, not in female MA abusers, relative to comparison subjects of the respective gender. We report that frontal WM integrity of MA abusers is compromised. This finding may also be related to impairment in frontal executive function. In addition, the neurotoxic effect of MA on frontal WM may be less prominent in women than in men, possibly due to oestrogen's neuroprotective effect.

An automated procedure for the assessment of white matter hyperintensities by multispectral (T1, T2, PD) MRI and an evaluation of its between-centre reproducibility based on two large community databases

INTRODUCTION

An automated procedure for the detection, quantification, localization and statistical mapping of white matter hyperintensities (WMH) on T2-weighted magnetic resonance (MR) images is presented and validated based on the results of a between-centre reproducibility study.

METHODS

The first step is the identification of white matter (WM) tissue using a multispectral (T1, T2, PD) segmentation. In a second step, WMH are identified within the WM tissue by segmenting T2 images, isolating two different classes of WMH voxels - low- and high-contrast WMH voxels, respectively. The reliability of the whole procedure was assessed by applying it to the analysis of two large MR imaging databases (n = 650 and n= 710, respectively) of healthy elderly subjects matched for demographic characteristics.

RESULTS

Average overall WMH load and spatial distribution were found to be similar in the two samples, (1.81 and 1.79% of the WM volume, respectively). White matter hyperintensity load was found to be significantly associated with both age and high blood pressure, with similar effects in both samples. With specific reference to the 650 subject cohort, we also found that WMH load provided by this automated procedure was significantly associated with visual grading of the severity of WMH, as assessed by a trained neurologist.

CONCLUSION

The results show that this method is sensitive, well correlated with semi-quantitative visual rating and highly reproducible.