Abnormal white matter integrity in chronic users of codeine-containing cough syrups: a tract-based spatial statistics study

Inflammatory, oxidative stress and cognitive functions in patients under maintenance treatment with methadone or buprenorphine and healthy subjects

BACKGROUND

Methadone and buprenorphine which are widely used for opioid maintenance treatment can affect redox status and also brain functions. The present study aimed to compare inflammation, oxidative stress, and cognitive function in methadone maintenance patients (MMP), buprenorphine maintenance patients (BMP), and healthy participants.

METHOD

Oxidative- antioxidant markers, inflammatory factors were investigated in MMP (n = 30), BMP (n = 30), and healthy participants (n = 30) by evaluating the ferritin, malondialdehyde (MDA), total antioxidant capacity (TAC), and also High-sensitivity C-reactive protein (hs-CRP). Also, executive function was evaluated using Wisconsin Card Sorting Test (WCST).

FINDINGS

MMP and BMP showed impairment in executive function compared to the healthy participants. Both buprenorphine and methadone treatments induced oxidative stress. The ferritin level in BMP was significantly lower compared to MMP and healthy participants (P = 0.01). There was a significant difference between control and MMP and BMP (P > 0.0001) in terms of hs-CRP level. BMP had the highest and healthy participant's lowest MDA level (P < 0.001). The TAC levels in BMP were lower than in MMP (p = 0.002) and healthy participants (p = 0.001). Finally, executive function was significantly correlated with oxidative-antioxidant status.

DISCUSSION

Both methadone and buprenorphine induced severe oxidative activity (especially buprenorphine) and cognitive deficits compared to healthy participants. Stress oxidative can affect normal brain activity and consequently cognitive functions. It's suggested that concomitant antioxidant administration with buprenorphine or methadone can potentially enhance their beneficial action by regulating blood redox status.

Abnormal white matter within brain structural networks is associated with high-impulse behaviour in codeine-containing cough syrup dependent users

Codeine-containing cough syrup (CCS) is considered as one of the most popular drug of dependence among adolescents because of its inexpensiveness and easy availability. However, its relationship with neurobiological effects remains sparsely explored. Herein, we examined how high-impulse behaviours relate to changes in the brain structural networks. Forty codeine-containing cough syrup dependent (CCSD) users and age-, gender-, and number of cigarettes smoked per day -matched forty healthy control (HC) subjects underwent structural brain imaging via MRI. High-impulse behaviour was assessed using the 30-item self-rated Barratt Impulsiveness Scale (BIS-11), and structural networks were constructed using diffusion tensor imaging and AAL-90 template. Between-group topological metrics were compared using nonparametric permutations. Benjamin-Hochberg false discovery rate correction was used to correct for multiple comparisons (P < 0.05). The relationships between abnormal network metrics and clinical characteristics of CCS dependent (BIS-11 total score, CCS- dependent duration and mean dose) were examined by Spearman's correlation. Structural networks of the CCSD group demonstrated lower small-world properties than those of the HC group. Abnormal changes in nodal properties among CCSD users were located mainly in the frontal gyrus, inferior parietal lobe and olfactory cortex. NBS analysis further indicated disrupted structural connections between the frontal gyrus and multiple brain regions. There were significant correlations between abnormal nodal properties of the frontal gyrus and clinical characteristics (BIS-11 total score, CCS dependent duration and mean dose) in the CCSD group. These findings suggest that the high-impulse behavioural expression in CCS addiction is associated with widespread brain regions, particularly within those in the frontal cortex. Aberrant brain regions and disrupted connectivity of structural network may be the bases of neuropathology for underlying symptoms of high-impulse behaviours in CCSD users, which may provide a novel sight to better treat and prevent codeine dependency in adolescents.

Microscopic features of the rat adrenal gland associated with chronic codeine phosphate administration

Codeine is an opioid analgesic and antitussive that has been widely abused. Some adverse effects noted with its abuse include adrenocortical insufficiency and activation of the hypothalamic-pituitary-adrenal axis. The structural basis for these dysfunctions is not clearly understood. Twenty-five adult male rats were used for the study. They were divided into intervention and control groups that were administered 40 mg/kg of codeine phosphate and normal saline respectively by gavage daily for 50 days. Subsequently, both groups were given normal saline for a further fourteen days to note recovery changes. At day 0, 50 and 64, rats were randomly selected from both groups, euthanized and adrenal glands harvested for histological processing and analysis. At day 50 of codeine administration, the adrenal glands demonstrated an increase in zona fasciculata thickness but a decrease in zona reticularis thickness. Lower values were noted in the volume density of zona reticularis and cells count of the medulla in the experimental compared to the control groups (P-value<0.05). The experimental group also showed an increase in vascularization and connective tissue in the glands. After 14 days of recovery, most of the changes observed in experimental animals were reversed and the adrenal glands in both groups had similar features. A decrease in cell count of the adrenal medulla was however observed (P-value<0.05). In conclusion administration of codeine phosphate causes discernible changes in the microscopic structure of the adrenal gland, most of which appear to be reversed after two weeks recovery period.

Cognitive profiles in persons with opioid use disorder enrolled in methadone treatment

Cognitive impairment is common in persons with opioid use disorder and associated with poor treatment outcomes, including elevated risk for relapse. Much less is known about the underlying structure of these deficits and the possible presence of cognitive phenotypes. A total of 177 adults (average 42.2 years of age, 52.0% male, 65.5% Caucasian) enrolled in a methadone maintenance treatment program completed the NIH Toolbox as part of a larger project. Cluster analyses revealed a 2-cluster solution-persons with intact cognitive function in all domains (n = 93; Intact) and those with impairments on tests of attention and executive function (n = 83; Impaired). Follow-up analyses revealed that the Impaired group was slightly older, more likely to self-identify as a racial/ethnic minority, and less likely to report consuming alcohol four or more times per week. These findings suggest the existence of distinct cognitive profiles in persons with opioid use disorder and encourage further examination, particularly studies to examine the possible benefits of routine screening for cognitive impairment as part of substance use treatment.

Potential gray matter unpruned in adolescents and young adults dependent on dextromethorphan-containing cough syrups: evidence from cortical and subcortical study

Adolescence is a unique period in neurodevelopment. Dextromethorphan (DXM)-containing cough syrups are new addictive drugs used by adolescents and young adults. The effects of chronic DXM abuse on neurodevelopment in adolescents and young adults are still unknown. The aim of this study was to investigate the differences in cortical thickness and subcortical gray matter volumes between DXM-dependent adolescents and young adults and healthy controls, and to explore relationships between alternations in cortical thickness/subcortical volume and DXM duration, initial age of DXM use, as well as impulsive behavior in DXM-dependent adolescents and young adults. Thirty-eight DXM-dependent adolescents and young adults and 18 healthy controls underwent magnetic resonance imaging scanning, and cortical thickness across the continuous cortical surface was compared between the groups. Subcortical volumes were compared on a structure-by-structure basis. DXM-dependent adolescents and young adults exhibited significantly increased cortical thickness in the bilateral precuneus (PreC), left dorsal lateral prefrontal cortex (DLPFC. L), left inferior parietal lobe (IPL. L), right precentral gyrus (PreCG. R), right lateral occipital cortex (LOC. R), right inferior temporal cortex (ITC. R), right lateral orbitofrontal cortex (lOFC. R) and right transverse temporal gyrus (TTG. R) (all p < 0.05, multiple comparison corrected) and increased subcortical volumes of the right thalamus and right pallidum. There was a significant correlation between initial age of DXM use and cortical thickness of the DLPFC. L and PreCG. R. A significant correlation was also found between cortical thickness of the DLPFC. L and impulsive behavior in patients. This was the first study to explore relationships between cortical thickness/subcortical volume and impulsive behavior in adolescents dependent on DXM. These structural changes might explain the neurobiological mechanism of impulsive behavior in adolescent DXM users.

Abnormal degree centrality in chronic users of codeine-containing cough syrups: A resting-state functional magnetic resonance imaging study

Codeine-containing cough syrups (CCS) have become one of the most popular drugs of abuse in young population worldwide. However, the neurobiological mechanisms underlying CCS-dependence are yet ill-defined. Therefore, understanding the brain abnormalities in chronic users of CCS is crucial for developing effective interventions. The present study depicted the intrinsic dysconnectivity pattern of whole-brain functional networks at the voxel level in chronic users of CCS. In addition, the degree centrality (DC) changes were correlated to the Barratt Impulsiveness Scale (BIS-11) total score, dose, duration of CCS use, and the age at first use of cough syrups. The current study included 38 chronic CCS users and 34 matched control subjects. All patients were evaluated using the BIS-11. Next, resting-state functional magnetic resonance imaging (rs-fMRI) datasets were acquired from these CCS users and controls. Whole-brain connectivity was analyzed using a graph theory approach: degree centrality (DC). CCS-dependent individuals exhibited low DC values in the left inferior parietal lobule and the left middle temporal gyrus, while high DC values were noted in the right pallidum and the right hippocampus (P < 0.01, AlphaSim corrected). Also, significant correlations were established between average DC value in the left inferior parietal lobule and attentional impulsivity scores and the age at first CCS use. The rs-fMRI study suggested that the abnormal intrinsic dysconnectivity pattern of whole-brain functional networks may provide an insight into the neural substrates of abnormalities in the cognitive control circuit, the reward circuit, and the learning and memory circuit in CCS-dependent individuals.

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The abuse of CCS has gained a severe foothold among young individuals worldwide.

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DC is one of the more reliable and compelling measures among several nodal network metrics.

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The present study depicted intrinsic dysconnectivity pattern of whole-brain functional networks in CCS-dependent individuals.

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CCS-dependent individuals showed altered DC in the right pallidum, right hippocampus, left IPL and left middle temporal gyrus.

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Significant correlations were established between average DC value in the left IPL and attentional impulsivity scores and the age at first CCS use.

Analysis of alterations in white matter integrity of adult patients with comitant exotropia

Objective

This study was performed to investigate structural abnormalities of the white matter in patients with comitant exotropia using the tract-based spatial statistics (TBSS) method.

Methods

Diffusion tensor imaging data from magnetic resonance images of the brain were collected from 20 patients with comitant exotropia and 20 age- and sex-matched healthy controls. The FMRIB Software Library was used to compute the diffusion measures, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). These measures were obtained using voxel-wise statistics with threshold-free cluster enhancement.

Results

The FA values in the right inferior fronto-occipital fasciculus (IFO) and right inferior longitudinal fasciculus were significantly higher and the RD values in the bilateral IFO, forceps minor, left anterior corona radiata, and left anterior thalamic radiation were significantly lower in the comitant exotropia group than in the healthy controls. No significant differences in the MD or AD values were found between the two groups.

Conclusions

Alterations in FA and RD values may indicate the underlying neuropathologic mechanism of comitant exotropia. The TBSS method can be a useful tool to investigate neuronal tract participation in patients with this disease.

Quantifying absolute glutamate concentrations in nucleus accumbens of prescription opioid addicts by using 1H MRS

INTRODUCTION

The diagnosis of psychoactive substance use disorders has been based primarily on descriptive, symptomatic checklist criteria. In opioid addiction, there are no objective biological indicators specific enough to guide diagnosis, monitor disease status, and evaluate efficacy of therapeutic interventions. Proton magnetic resonance spectroscopy (¹H MRS) of the brain has potential to identify and quantify biomarkers for the diagnosis of opioid dependence. The purpose of this study was to detect the absolute glutamate concentration in the nucleus accumbens (NAc) of patients with prescription opioid dependence using ¹H MRS, and to analyze its clinical associations.

METHODS

Twenty patients with clinically diagnosed definitive prescription opioid dependent (mean age = 26.5 ± 4.3 years) and 20 matched healthy controls (mean age = 26.1 ± 3.8 years) participated in this study. Patients were evaluated with the Barratt Impulsiveness Scale (BIS-11), the Self-Rating Anxiety Scale (SAS), and the opiate Addiction Severity Inventory (ASI). We used point-resolved spectroscopy to quantify the absolute concentrations of metabolites (glutamate, choline, N-acetylaspartate, glutamine, creatine) within the NAc. The difference between metabolite levels of groups and Pearson's correlation between glutamate levels and psychometric scores in patients were analyzed statistically.

RESULTS

Glutamate concentrations in the NAc were significantly higher in prescription opiate addicts than in controls (t = 3.84, p = .001). None of the other metabolites differed significantly between the two groups (all ps > .05). The glutamate concentrations correlated positively with BIS-11 scores in prescription opiate addicts (r = .671, p = .001), but not with SAS score and ASI index.

CONCLUSIONS

Glutamate levels in the NAc measured quantitatively with in vivo ¹H MRS could be used as a biomarker to evaluate disease condition in opioid-dependent patients.

Intrinsic brain network abnormalities in codeine-containing cough syrup-dependent male individuals revealed in resting-state fMRI

PURPOSE

To identify codeine-containing cough syrups (CCS)-related modulations of intrinsic connectivity network (ICN) and to investigate whether these changes of ICN can be related to duration of CCS use and to impulsivity behavior in CCS-dependent individuals.

MATERIALS AND METHODS

Resting-state functional magnetic resonance imaging (fMRI) data in 41 CCS-dependent individuals and 34 healthy controls (HC) were scanned at 1.5T and analyzed using independent component analysis (ICA), in combination with a "dual-regression" technique to identify the group differences of three important resting-state networks, the default mode network (DMN), the executive control network (ECN), and the salience network (SN) between the CCS-dependent individuals and HC.

RESULTS

Compared with the HC, CCS-dependent individuals had aberrant intrinsic connectivity within the DMN, ECN, and SN (P < 0.05, AlphaSim corrected). Furthermore, a longer duration of CCS use was associated with greater abnormalities in the intrinsic network functional connectivity (FC, P < 0.05, Bonferroni correction). Intrinsic network FC also correlated with higher impulsivity in CCS-dependent individuals (P < 0.05, AlphaSim corrected).

CONCLUSION

Our findings revealed aberrant DMN, ECN, and SN connectivity patterns in CCS-dependent patients, which may provide new insight into how neuronal communication and information integration are disrupted among DMN, ECN, and SN key structures due to long duration of CCS use.

LEVEL OF EVIDENCE

1 J. Magn. Reson. Imaging 2017;45:177-186.

Larger corpus callosum and reduced orbitofrontal cortex homotopic connectivity in codeine cough syrup-dependent male adolescents and young adults

OBJECTIVES

To characterize interhemispheric functional and anatomical connectivity and their relationships with impulsive behaviour in codeine-containing cough syrup (CCS)-dependent male adolescents and young adults.

METHODS

We compared volumes of corpus callosum (CC) and its five subregion and voxel-mirrored homotopic functional connectivity (VMHC) in 33 CCS-dependent male adolescents and young adults and 38 healthy controls, group-matched for age, education and smoking status. Barratt impulsiveness scale (BIS.11) was used to assess participant impulsive behaviour. Abnormal CC subregions and VMHC revealed by group comparison were extracted and correlated with impulsive behaviour and duration of CCS use.

RESULTS

We found selective increased mid-posterior CC volume in CCS-dependent male adolescents and young adults and detected decreased homotopic interhemispheric functional connectivity of medial orbitofrontal cortex (OFC). Moreover, impairment of VMHC was associated with the impulsive behaviour and correlated with the duration of CCS abuse in CCS-dependent male adolescents and young adults.

CONCLUSIONS

These findings reveal CC abnormalities and disruption of interhemispheric homotopic connectivity in CCS-dependent male adolescents and young adults, which provide a novel insight into the impact of interhemispheric disconnectivity on impulsive behaviour in substance addiction pathophysiology.

KEY POINTS

• CCS-dependent individuals (patients) had selective increased volumes of mid-posterior corpus callosum • Patients had attenuated interhemispheric homotopic FC (VMHC) of bilateral orbitofrontal cortex • Impairment of VMHC correlated with impulsive behaviour in patients • Impairment of VMHC correlated with the CCS duration in patients.

Nonmedical Use of Cough Syrup Among Secondary Vocational School Students: A National Survey in China

Nonmedical use of cough syrup (NUCS) among secondary vocational school (SVS) students has been an increasing concern for public health in China, but no data were available. This cross-sectional study aimed to investigate the epidemiological characters of NUCS as well as its risk factors among SVS students in China.From September 2013 to December 2014, a total of 13,614 SVS students were purposively selected through multistage sampling in 6 cities of China. Information on NUCS, demographics, family background, smoking and alcohol consumption, impulsiveness, sensation seeking, and parental monitoring were collected. Logistic regression was used to explore factors related to NUCS.The 12,923 (94.9%) valid responses (16.3 ± 1.0 years old, and 52.6% men) reported 3.47% (95% confidence interval: 3.15-3.79%) lifetime NUCS. Logistic regression indicated that smoking, part-time job experience, high level of impulsiveness, and sensation seeking were risk factors for NUCS, whereas urban living and high parental monitoring were protective ones.NUCS was prevalent among SVS students. Interventions that target on smoking, impulsiveness and sensation seeking control, improvement on parental monitoring may have considerable impact on NUCS among SVS students.

Short-term UROD treatment on cerebral function in codeine-containing cough syrups dependent male individuals

OBJECTIVE

To investigate alterations of resting brain function in codeine-containing cough syrups (CCS) dependent individuals before and after ultra-rapid opioid detoxification under general anaesthesia (UROD) combined with naltrexone treatment (NMT).

METHODS

Fourteen CCS-dependent individuals were scanned using resting-state fMRI. After UROD and 2 weeks of NMT, CCS-dependent individuals were rescanned. Fourteen matched controls were studied at baseline and compared. The amplitude of low frequency fluctuations (ALFF) and seed-based functional connectivity (FC) were used to characterize resting-state cerebral function.

RESULTS

After UROD and 2 weeks of NMT, CCS-dependent individuals had increased ALFF in the bilateral parahippocampal gyrus and right medial orbitofrontal cortex (mOFC), decreased ALFF in the left post-central gyrus (PoCG), left middle occipital cortex (MOC) and left dorsal lateral prefrontal cortex (DLPFC), and reduced FC between right mOFC and right DLPFC, and between left DLPFC and left inferior parietal lobe relative to pretreatment. Decreased ALFFs in the left PoCG and left MOC were associated with decreased withdrawal syndrome severity in CCS-dependent individuals.

CONCLUSIONS

We offer the first report describing how regional and integral synchronous neural activity occurs after UROD and short-term NMT, accompanied by decreased withdrawal syndrome severity. These findings contribute to the understanding of complex systems involved in UROD-NMT effects.

KEY POINTS

• CCS-dependent individuals had reduced ALFF and increased FC at baseline. • UROD treatment can change the regional and integral brain function of CCS-dependent individuals. • Attenuated ALFFs are correlated with the withdrawal syndrome after treatment.