Increased serum brain-derived neurotrophic factor levels during opiate withdrawal

Serum brain-derived neurotrophic factor in relation to craving and duration of abstinence in patients with heroin dependence-A case-control study

BACKGROUND AND OBJECTIVES

Addiction is a chronic disorder that comes with emotional and financial burdens. Several neurobiological factors were correlated to opiate-use disorder which is brain-derived neurotrophic factor (BDNF). BDNF has been found to be involved in long-term potentiation of synaptic strength, a mechanism that is thought to motivate both natural adaption mechanisms as well as the development of addictive behavior. In this study, we aimed to address the relation between BDNF serum level and heroin craving and the effect of duration of abstinence on them.

METHODS

A case study was conducted on 80 subjects from Kasr Al-Ainy Psychiatry and Addiction Treatment Hospital with a history of heroin dependence and were divided into two groups: Group A had 40 active heroin-dependent subjects while in Group B, 40 subjects with 1-year heroin abstinence. Severity of addiction was assessed by the addiction severity index, heroin craving was measured by Brief Substance Craving Scale and serum BDNF level was investigated using an enzyme-linked immunosorbent assay.

RESULTS

The findings show that active heroin users had significantly higher serum BDNF which is associated with high heroin craving in comparison to the abstinent group.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

This study revealed a significant positive correlation between serum BDNF levels and craving in active heroin users versus 1-year abstinent subjects. It is the first study to address the relationship between craving and serum BDNF level in a 1-year abstinent participants. These findings help to determine the brain alterations associated with illness and recovery in heroin dependence.

Potential role of the lncRNA "HOTAIR"/miRNA "206"/BDNF network in the alteration in expression of synaptic plasticity gene arc and BDNF level in sera of patients with heroin use disorder through the PI3K/AKT/mTOR pathway compared to the controls

INTRODUCTION

Heroin use disorder (HUD) is a seriously increasing health issue, accounting for most deaths among drug abusers. Studying non-coding ribonucleic acid gene expression among drug abusers is a promising approach, as it may be used in diagnosis and therapeutics.

PARTICIPANTS AND METHODS

A total of 49 male heroin-dependent patients and 49 male control participants were recruited from Kasr Al Ainy Psychiatry and Addiction outpatient clinics, Faculty of Medicine, Cairo University. Sera were gathered. qRT-PCR was utilized for the detection of gene expression of non-coding RNAs such as "HOX transcript antisense RNA" (HOTAIR), micro-RNA (miRNA-206), phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), mechanistic target of rapamycin (mTOR), and Activity Regulated Cytoskeleton Associated Protein (Arc). Sera Brain-Derived Neurotrophic Factor (BDNF) levels were assessed using ELISA. Using a western blot made it possible to determine the protein expression of PI3K, AKT, and mTOR.

RESULTS

The study demonstrated that gene expressions of HOTAIR, AKT, PI3K, and Arc were considerably lowered between cases and controls, while gene expressions of miR-206 and mTOR1 were significantly raised. PI3K and AKT protein expressions were downregulated, while mTOR expressions were upregulated. BDNF levels were significantly decreased in some cases.

CONCLUSION

The results of this study suggest that decreased HOTAIR in HUD relieves miR-206 inhibition, which thus increases and affects downstream PI3K/AKT/mTOR, ARC, and BDNF expression. This may be shared in addictive and relapsing behaviors.

Brain-derived neurotrophic factor serum levels as a candidate biomarker for withdrawal in crack heroin dependence

BACKGROUND

Crack heroin is a novel opiate derivative with highly addictive properties and unfamiliar health consequences. It causes a variety of brain dysfunctions that are mediated by neurochemical alterations and abnormal neuroplasticity. Brain-derived neurotrophic factor (BDNF) is a widely recognized biological marker implicated in the neuropathology of substance use during substance use disorder and withdrawal. Its involvement can significantly contribute to the severity of withdrawal symptoms. Hence, this study aimed to evaluate BDNF levels in crack heroin users before and after withdrawal.

METHODS

In this cross-sectional study, 148 male participants were recruited and divided into two groups: persons with crack heroin use disorder (n = 74) and the controls (n = 74). The BDNF serum levels were measured in both crack heroin users and control groups upon hospitalization and again after twenty-one days of withdrawal using the enzyme-linked immunosorbent assay.

RESULTS

The results demonstrated that BDNF levels in persons with crack heroin use disorder upon admission were significantly lower than the levels observed upon discharge and in the control group (p < 0.05). Additionally, a significant difference in BDNF levels was found between persons with crack heroin use disorder at admission and discharge (p = 0.038). Furthermore, BDNF levels showed an inverse correlation with the daily dose of substance use (r= -0.420, p = 0.03) and the duration of crack heroin use (r= -0.235, p = 0.001).

CONCLUSIONS

A progressive increment in BDNF levels during early detoxification is associated with the daily amount of substance use and the duration of substance use. Our findings suggest that changes in BDNF serum levels during crack heroin use disorder and withdrawal could serve as potential biomarkers for assessing the intensity of withdrawal symptoms and substance use-related behaviors.

Aerobic exercise as a promising nonpharmacological therapy for the treatment of substance use disorders

Despite the prevalence and public health impact of substance use disorders (SUDs), effective long-term treatments remain elusive. Aerobic exercise is a promising, nonpharmacological treatment currently under investigation as a strategy for preventing drug relapse. Aerobic exercise could be incorporated into the comprehensive treatment regimens for people with substance abuse disorders. Preclinical studies of SUD with animal models have shown that aerobic exercise diminishes drug-seeking behavior, which leads to relapse, in both male and female rats. Nevertheless, little is known regarding the effects of substance abuse-induced cellular and physiological adaptations believed to be responsible for drug-seeking behavior. Accordingly, the overall goal of this review is to provide a summary and an assessment of findings to date, highlighting evidence of the molecular and neurological effects of exercise on adaptations associated with SUD.

Efficacy of continuous theta burst stimulation - repetitive trancranial magnetic stimulation on the orbito frontal cortex as an adjunct to naltrexone in patients of opioid use disorder and its correlation with serum BDNF levels: a sham-controlled study

Background: Opoid use disorder (OUD) is a global illness and reduction in craving by repeatative Transcranial Magnetic Stimulation (RTMS) is one of its management approaches. Orbito-frontal Cortex is implicated in the several behavioral aspects of substance use including craving. Brain derived neurotrophic factor (BDNF) has a critical role in addictive properties of drugs of use. Previous studies have shown significant improvement in craving with RTMS and demonstrated alterations of serum BDNF levels in various substance dependent individual associated with craving. Aim: To examine the efficacy of continuous Theta Burst Stimulation RTMS (CTBS-RTMS) over the right OFC as an adjunct to Naltrexone in patients of OUD and its correlation with serum BDNF levels. Methods: Forty patients with OUD were recruited with purposive sampling. At the end of detoxification CTBS -RTMS was applied by dividing them into two equal groups as active and sham group using alternate allocation. Obsessive compulsive drug use scale (OCDUS) was applied and serum BDNF level was measured overtime till the end of CTBS-RTMS session. Data was analyzed by SPSS version 25. Results: Both groups had shown significant reduction in craving (OCDUS score) and serum BDNF from the baseline to 14th session of the RTMS. But there was no significant difference when compared between the two groups. Significant correlation was observed between serum BDNF levels overtime with different clinical variables in active group. Conclusion: The study adds to the literature in building an understanding of how rTMS could be used in reducing cravings for opioids.

Alterations in neurotransmitter levels and transcription factor expression following intranasal buprenorphine administration

Buprenorphine is an opioid drug used in the management of pain and the treatment opioid addiction. Like other opioids, it is believed that it achieves these effects by altering functional neurotransmitter pathways and the expression of important transcription factors; cyclic AMP response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in the brain. However, there is a lack of scientific evidence to support these theories. This study investigated the pharmacodynamic effects of BUP administration by assessing neurotransmitter and molecular changes in the healthy rodent brain. Sprague-Dawley rats (150-200 g) were intranasally administered buprenorphine (0.3 mg/mL) and sacrificed at different time points: 0.25, 0.5, 1, 2, 4, 6, 8 and 24 h post drug administration. LC-MS was used to quantify BUP and neurotransmitters (GABA, GLUT, DA, NE and 5-HT) in the brain, while CREB and BDNF gene expression was determined using qPCR. Results showed that BUP reached a Cmax of 1.21 ± 0.0523 ng/mL after 2 h, with all neurotransmitters showing an increase in their concentration over time, with GABA, GLUT and NE reaching their maximum concentration after 8 h. DA and 5-HT reached their maximum concentrations at 1 h and 24 h, respectively post drug administration. Treatment with BUP resulted in significant upregulation in BDNF expression throughout the treatment period while CREB showed patterns of significant upregulation at 2 and 8 h, and downregulation at 1 and 6 h. This study contributes to the understanding of the pharmacodynamic effects of BUP in opioid addiction by proving that the drug significantly influences NT pathways that are implicated in opioid addiction.

The use of recombinant tissue plasminogen activator in in acute ischemic stroke is associated with increased level of BDNF

Much concern was directed towards the crucial role of recombinant tissue plasminogen activator (rt-PA) in improving neuroplasticity in patients with acute ischemic stroke. The aim of the work to investigate the effect of treating patients with acute ischemic stroke with rt-PA, on the level of brain derived neurotrophic factor (BDNF) as a marker of neuroplasticity. This study was conducted on 47 patients presenting with acute ischemic stroke (during the first 4.5 h from stroke onset); 26 patients of them eligible for receiving rt-PA (patient group) and 21 patients having contraindications for treatment with rt-PA (control group). Neurological, radiological and laboratory assessment (including BDNF serum level) were done for both groups at stroke onset (before receiving rt-PA) and at day 7. There was a statistically significant increase in BDNF serum level from day 1 to day 7 in rt-PA treated patients in comparison to control group (P-value˂ 0.001). Serum level of BDNF is significantly higher at the onset of stroke in female patients and non-smokers than males or smokers (P-value = 0.011, 0.01 respectively). There was no effect of either age, body mass index, hypertension, diabetes, drug abuse, past or family history of stroke, valvular heart diseases, atrial fibrillation, cardiomyopathy, ejection fraction, carotid atherosclerotic changes, lipid profile or uric acid, on BDNF serum level measured at the onset of stroke. Treatment of patients with acute ischemic stroke with rt-PA causes significant improvement in neuroplasticity through increasing BDNF serum level.

Pomegranate-derived anthocyanin regulates MORs-cAMP/CREB-BDNF pathways in opioid-dependent models and improves cognitive impairments

BACKGROUND

Pomegranate (Punica granatum) is one of the oldest known edible fruit. Recently, there has been an increased interest in this fruit as a functional food for health benefits due to its use in disease prevention and promotion of overall health wellness.

OBJECTIVE

This study aims to investigate the effects of pomegranate extract for the development of non-opioid substitution therapy for in-vitro and in-vivo studies.

MATERIALS AND METHODS

Anthocyanin contents consisting of cyanidin 3-glucoside, diglucoside, and pelargonidin 3-glucoside, diglucoside were detected and quantified in pomegranate extract using high-performance liquid chromatography. The optimum dosage of the extract was determined based on the regulation of MORs and cAMP proteins in U-87 cells. Co-treatment of the extract with morphine was performed to evaluate its potency in reducing the concentration levels of MORs and cAMP. For animal studies, rats were divided into two major groups representing both acute and chronic morphine-induced treatments and the Morris water maze (MWM) study was employed after treatment for each rat. The rats were sacrificed after the treatments and serum samples were collected to evaluate the levels of CREB and BDNF.

RESULTS

The results indicated that each of the anthocyanin content tested in the study was present in the pomegranate extract. Additionally, in-vitro studies using pomegranate extract treatment showed that the extract was effective in decreasing the MORs and cAMP protein levels in U-87 cells at a concentration of 0.125 mg/mL. The memory impairment based on the MWM study in rats was also subsequently improved after treatment with pomegranate extract as compared to treatment with morphine. The blood serum derived from the rats treated with pomegranate extract also showed a significant decrease in CREB level and an increase in BDNF as compared to rats treated with morphine.

CONCLUSION

In conclusion, this study substantiates the potency of pomegranate extract as a non-opioid substitution therapy for in-vitro and in-vivo studies.

Naloxone-precipitated withdrawal ameliorates impairment of cost-benefit decision making in morphine-treated rats: Involvement of BDNF, p-GSK3-β, and p-CREB in the amygdala

Several studies indicated that morphine administration impairs cognitive brain functions. Therefore, in the current study, we investigated the effect of subchronic exposure to morphine and its withdrawal on effort- and/or delay-based forms of cost-benefit decision making and alterations in p-CREB/CREB ratio, p-GSK3β/GSK3β ratio, and BDNF level during decision making in the amygdala. Our data displayed an impairment of both forms of cost-benefit decision making following subchronic exposure to morphine. However, preference of high reward/high effort and/or high delay reward increased after naloxone injection. In molecular section, levels of BDNF and p-CREB/CREB ratio increased during cost-benefit decision making while p-GSK3β/GSK3β ratio decreased in both forms of decision making. In morphine-treated rats, level of BDNF and p-CREB/CREB ratio reduced during both forms of decision making while p-GSK3β/GSK3β ratio increased during delay-based and did not have a significant difference with the control group during effort-based decision making. On the withdrawal day, BDNF level raised while p-GSK3β/GSK3β ratio attenuated compared to morphine-treated group in both form of decision making. In addition, p-CREB/CREB ratio increased only during delay-based decision making on the withdrawal day. In conclusion, our data revealed that subchronic exposure to morphine interferes with the cost-benefit decision making may be via changes in level of BDNF, p-CREB/CREB and p-GSK3β/GSK3β ratio in the amygdala.

Impact of different intensities of forced exercise on deficits of spatial and aversive memory, anxiety-like behavior, and hippocampal BDNF during morphine abstinence period in male rats

Forced exercise can alleviate cognitive-behavioral deficits in an experimental model of addiction. However, the effects of different intensities of forced exercise in improving behavioral, cognitive and biochemical deficits during morphine abstinence period are not well investigated. Thus, the current work examined the effects of different loads of forced exercise on cognition functions, anxiety behavior and BDNF changes in the hippocampus, and prefrontal cortex (PFC), and also serum levels of BDNF and corticosterone during the abstinent period in male rats. Animals received morphine injections (10 mg/kg, twice a day) for 10 consecutive days. Then, the animals were exposed to a 4-week forced exercise training program under low, moderate or high intensities (30 min per session on 5 days a week), which accompanied by behavioral and biochemical tests. In Experiment 1, anxiety-like behaviors using elevated plus maze (EPM), and light/dark box (L/D box) were examined. In Experiment 2, cognitive functions using T-maze alteration and passive avoidance tasks were tested, which accompanied by BDNF measurements in the hippocampus and PFC. In Experiment 3, serum levels of BDNF and corticosterone following the termination of forced exercise regimen were measured. Morphine-abstinent animals exhibited anxiogenic -like behaviors in the EPM, but not L/D box. They also exhibited impaired T-maze alternation performance and passive avoidance memory, and a decline in hippocampal BDNF, but not PFC. Forced exercise at a moderate intensity alleviated anxiety, cognitive and BDNF defects in morphine-abstinent animals. The high load exercise enhanced serum levels of corticosterone in both saline and morphine groups. Thus, regular moderate forced exercise may be beneficial in preserving cognitive and mood functions in male addicts during the abstinent period and drug rehabilitation.

Comparing the Efficacy of Anodal, Cathodal, and Sham Transcranial Direct Current Stimulation on Brain-Derived Neurotrophic Factor and Psychological Symptoms in Opioid-Addicted Patients

Introduction:

Today, addiction to opioids is a serious problem all over the world. Unfortunately, the consumption of these drugs and the number of addicted people have drastically increased. This research aimed at comparing the efficacy of anodal, cathodal, and sham transcranial Direct Current Stimulation (tDCS) on the Brain-Derived Neurotrophic Factor (BDNF) and psychological symptoms in opioid-addicted patients.

Methods:

Thirty opioid-addicted patients were selected based on the Diagnostic and Statistical Manual of Mental Disorders, the Fifth Edition, through the convenience sampling method. They were then randomly assigned to 3 groups (10 in each group). The subjects were evaluated before and after tDCS by their serum level of BDNF, desires for drug questionnaire, and depression anxiety stress scale. The data were analyzed by the Kolmogorov-Smirnov test, one-way analysis of variance, as well as the Bonferroni test.

Results:

Stimulating the Dorsolateral Prefrontal Cortex (DLPFC) led to a significant change in increasing the level of BDNF (P=0.031) and reducing the degree of depression (P=0.018), anxiety (P=0.001), stress (P=0.012), and decreased the level of craving (P=0.001) in opioid-addicted patients. There was no significant difference between active stimulation groups (anodal left/cathodal right and anodal right/cathodal left). The stimulation of the right DLPFC (group B) significantly increased BDNF in comparison with the sham group (sham tDCS) and decreased anxiety and craving. Nonetheless, no change was observed in depression and stress. The stimulation of the left DLPFC (group A) significantly reduced depression, anxiety, stress, and craving compared with the sham group, while there was no change in BDNF.

Conclusion:

In addition to the conventional treatments of opioid-addicted patients, tDCS is an effective complementary treatment.

Correlation between interleukin-6 levels and methadone maintenance therapy outcomes

BACKGROUND

The outcome of methadone maintenance therapy (MMT) varies in each patient with opioid use disorder (OUD). Opioid abuse activates proinflammatory processes by increasing cytokine production and impairing neurotrophic factor expression, and possibly leads to a vicious cycle that hinders recovery. Therefore, we investigated whether markers of inflammation and neurotrophic expression correlate with the MMT outcomes in OUD patients.

METHOD

We investigated OUD patients undergoing MMT and followed them up for 12 weeks. We measured plasma tumor necrosis factor (TNF)-α, C-reactive protein (CRP), interleukin (IL)-6, IL-1β, transforming growth factor (TGF)-β1, brain-derived neurotrophic factor (BDNF), urinary morphine tests, and plasma morphine levels at baseline and on weeks 1, 4, 8, and 12 during MMT. Multiple linear regressions and generalized estimating equations (GEEs) were used to examine the correlation between the cytokine and BDNF levels and MMT outcomes.

RESULTS

We initially enrolled 104 patients, but only 78 patients completed end-of-study assessments. Plasma levels of CRP, TGF-β1, and BDNF fell during MMT. Plasma IL-6 levels were significantly associated with plasma morphine levels (P = 0.005) and urinary morphine-positive (⁺) results (P = 0.04), and significantly associated with poor compliance (P = 0.009) and early dropout from MMT (P = 0.001). However, other cytokine and BDNF levels were not consistently associated with MMT outcomes.

CONCLUSION

Higher IL-6 levels were associated with poor MMT outcomes. Additional studies on regulating IL-6 expression to improve treatment outcomes in OUD patients might be warranted.

Brain-derived neurotrophic factor in substance use disorders: A systematic review and meta-analysis

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is associated with several neurodegenerative and psychiatric disorders. It is not clear, however, whether BDNF levels are modified in substance use disorders (SUDs).

METHODS

We conducted a systematic search of electronic databases to identify studies comparing peripheral plasma or serum BDNF levels in adults with SUDs vs. non-user controls. Forty studies were included in the meta-analysis involving a total of 2238 participants with SUDs and 2574 controls.

RESULTS

After trim and fill adjustment, current drug users presented lower serum BDNF levels (SMD = -0.99, 95%CI -1.40 to -0.58, I² = 95.9) than non-user controls. However, this difference disappears during withdrawal. Studies using serum or plasma BDNF samples have shown different results. Subgroup analysis revealed lower levels of serum BDNF in alcohol users (SMD = -0.70, 95%CI -1.15 to -0.25, I² = 89.81) and crack/cocaine users (SMD = -1.78, 95%CI -2.92 to -0.65, I² = 97.59) than controls. Meta-regression analysis revealed that gender, age, and age of first use moderate the effects of drug use in peripheral BDNF levels.

CONCLUSIONS

Peripheral BDNF levels are decreased in the serum, but not the plasma, of active drug users. Altogether, these findings suggest that BDNF levels may be related to acute use and addiction severity and also point to BDNF's potential utility as a biomarker in this population.

Correlation of cytokines, BDNF levels, and memory function in patients with opioid use disorder undergoing methadone maintenance treatment

BACKGROUND

Patients with opioid use disorder (OUD) show memory deficiencies and impaired treatment outcomes. Emerging evidence suggests that opioid abuse activates proinflammatory processes by increasing cytokine production and impairing neuroprotection, which damages the memory function in OUD patients. Therefore, we investigated whether plasma-based inflammatory and neurotrophic markers correlate with memory function in OUD patients.

METHOD

OUD patients undergoing methadone maintenance therapy (MMT) were investigated and followed up for 12 weeks. Plasma tumor necrosis factor (TNF)-α, C-reactive protein (CRP), interleukin (IL)-6, transforming growth factor (TGF)-β1, brain-derived neurotrophic factor (BDNF) levels, and Wechsler Memory Scale-Revised (WMS-R) scores were assessed at baseline and after 12 weeks of MMT. Multiple linear regressions and generalized estimating equations (GEEs) were used to examine the correlation between cytokines and memory performance.

RESULTS

We enrolled 89 patients at baseline; 47 patients completed the end-of-study assessments. Although Pearson correlations showed that CRP and TGF-β1 levels were significantly, negatively associated with some memory indices, the results were not significant after correction. The GEE results, controlled for several confounding factors and multiple testing, showed that changes in TNF-α levels were negatively correlated with changes in the visual memory index (P = 0.01), and that changes in IL-6 levels were negatively correlated with changes in the verbal memory index (P = 0.009).

CONCLUSION

Memory performance, TNF-α, and IL-6 levels in OUD patients were negative correlated. Additional studies on regulating TNF-α and IL-6 expression to improve memory function in OUD patients might be warranted.

Expression of brain-derived neurotrophic factors, neurotrophin-3, and neurotrophin-4 in the nucleus accumbens during heroin dependency and withdrawal

Neurotrophins, brain-derived neurotrophic factors (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4), have been implicated in the modulation of heroin dependency. This study was designed to explore the expression alterations of BDNF, NT-3, and NT-4 in the context of heroin dependence and withdrawal in the rat nucleus accumbens (NAc). Heroin dependence was induced by a progressive intraperitoneal treatment of heroin. The results showed that the expression levels of BDNF and NT-4 were significantly decreased in the NAc of rats with heroin addiction in comparison with the control group, whereas there was a significant increase in BDNF and NT-4 expressions in the groups of rats with both naloxone-induced and spontaneous withdrawal. Moreover, NT-3 expression was markedly increased in the NAc of rats with heroin addiction and spontaneous withdrawal in comparison with the control group, but decreased in the NAc of rats with naloxone-induced withdrawal. These results indicated that chronic administration of heroin results in the alterations of BDNF, NT-3, and NT-4 expressions in the rat NAc. BDNF, NT-3, and NT-4 may play a critical role in the development of heroin dependency and withdrawal.

Peripheral levels of BDNF and opiate-use disorder: literature review and update

Several neurobiological factors are related to opiate-use disorder (OUD), and among them, neurotrophins have a relevant role. Brain-derived neurotrophic factor (BDNF) is a central neurotrophin involved in many neuronal processes, and it has been related to several psychiatric diseases and addictive disorders. BDNF can be measured in plasma and serum; its levels may reflect BDNF concentrations in the central nervous system (CNS) and, indirectly, CNS processes. Hence, peripheral BDNF could be a biomarker in clinical practice. This manuscript explores the findings about peripheral BDNF and OUD in humans. Opiates induce neurotoxicity in the CNS, which may be correlated with modifications in BDNF expression. Thus, basal levels of peripheral BDNF in OUD patients may be altered, which could be modified with abstinence. Also, opiates may modify epigenetic processes that may be associated with peripheral concentrations of BDNF, and in this line, withdrawal could reflect recovering processes in the CNS. Additionally, treatment modifies the peripheral concentrations of BDNF, but the clinical implications of those changes are yet not elucidated. No specific conclusion can be performed and more investigation in this area is necessary to elucidate the real potential of peripheral BDNF as a biomarker.

Pharmacoepigenomics of opiates and methadone maintenance treatment: current data and perspectives

Current treatments of opioid addiction include primarily maintenance medications such as methadone. Chronic exposure to opiate and/or long-lasting maintenance treatment induce modulations of gene expression in brain and peripheral tissues. There is increasing evidence that epigenetic modifications underlie these modulations. This review summarizes published results on opioid-induced epigenetic changes in animal models and in patients. The epigenetic modifications observed with other drugs of abuse often used by opiate abusers are also outlined. Specific methadone maintenance treatment induced epigenetic modifications at different treatment stages may be combined with the ones resulting from patients’ substance use history. Therefore, research comparing groups of addicts with similar history and substances use disorders but contrasting for well-characterized treatment phenotypes should be encouraged.

Increased BDNF may not be associated with cognitive impairment in heroin-dependent patients

A growing number of evidence suggests that brain-derived neurotrophic factor (BDNF) plays an important part in modulating the activities on the basis of hippocampus neural plasticity, such as learning and memory. Heroin addiction has a series of cognitive impairments that may be associated with BDNF. In this study, we explored the association of BDNF with cognitive function in heroin-dependent patients.We enrolled 86 heroin-dependent patients and 238 normal control subjects and examined their cognition by the repeatable battery for the assessment of neuropsychological status (RBANS) and serum BDNF levels in 2 groups.BDNF levels were significantly higher in patients than controls (P < .001). Cognitive scores of the RBANS showed that attention and language index (P < .05) were significantly lower in heroin-dependent patients than control groups. Unfortunately, we found no positive association between BDNF and cognitive function in patients, except that BDNF was positively associated with visuospatial/constructional index in control groups.Our findings suggest that BDNF may not be involved in the pathophysiology of heroin dependence, but more studies about cognitive impairment in heroin addiction are needed.

Brain-derived neurotrophic factor (BDNF) and oxidative stress in heroin-dependent male patients undergoing methadone maintenance treatment

Brain-derived neurotrophic factor (BDNF) and oxidative stress may play a role in patients with heroin dependence. The aim of this study was to investigate the serum levels and activities of BDNF and oxidative stress markers, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), thiobarbituric acid reactive substances (TBARS), protein carbonyl content (PCC), and 8-hydroxy 2'-deoxyguanosine (8-OHdG), in heroin-dependent patients undergoing methadone maintenance treatment (MMT). 60 heroin-dependent male MMT patients and 30 healthy males were recruited for this study. The serum BDNF and oxidative stress markers of these subjects were measured with assay kits. Analyses of covariance (ANCOVAs) with age and body mass index adjustments indicated that the serum levels of BDNF in the MMT patients were significantly higher than those in the healthy controls (F=5.169; p=0.026). However, there were no significant differences between the heroin-dependent patients and the healthy controls in the serum levels or activities of oxidative stress markers (p>0.05). In conclusion, our results suggest that MMT increases BDNF levels in heroin-dependent patients, and that patients undergoing MMT might be in a balanced state of reduced oxidation.

Plasma Brain-Derived Neurotrophic Factor and Psychopathology in Attempted Suicide

BACKGROUND/AIMS

Increasing evidence suggests a link between brain-derived neurotrophic factor (BDNF) and suicidal behaviour (SB). Furthermore, decreased peripheral BDNF levels have been associated with clinical symptoms in various psychiatric disorders as well as with personality dimensions in healthy individuals. However, the relationship between BDNF and psychopathology is poorly investigated regarding SB.

METHODS

Plasma BDNF concentrations were analysed in 61 recent suicide attempters. Clinical symptoms were evaluated using the Comprehensive Psychopathological Rating Scale. Personality dimensions were assessed using the Marke-Nyman Temperament Scale.

RESULTS

Plasma BDNF correlated positively and significantly with the personality dimension Solidity but not with the other personality dimensions or with clinical symptoms.

CONCLUSION

BDNF plays an important role in the regulation of neuroplasticity and neurogenesis in humans. Our results indicate that lower BDNF concentrations are associated with higher levels of impulsiveness and changeability (low scores on the Solidity scale). Furthermore, low plasma BDNF levels may be proposed as a trait marker rather than a state marker for attempted suicide.

Elevated methylation and decreased serum concentrations of BDNF in patients in levomethadone compared to diamorphine maintenance treatment

Brain-derived neurotrophic factor (BDNF) appears to play a crucial role in the reward response to drugs such as heroin. The primary objective of the present study was to examine epigenetic changes and serum levels of BDNF in patients undergoing different opiate-based maintenance treatments. We compared patients receiving treatment with either levomethadone (n = 55) or diamorphine (n = 28) with a healthy control group (n = 51). When comparing all subjects (patients and controls), BDNF serum levels showed a negative correlation with the BDNF IV promoter methylation rate (r = -0.177, p = 0.048). Furthermore, BDNF serum levels negatively correlated with Beck's Depression Inventory measurements (r = -0.177, p < 0.001). Patients receiving diamorphine maintenance treatment showed slightly decreased BDNF serum levels compared to healthy controls, whereas patients on levomethadone maintenance treatment with or without heroine co-use showed a pronounced decrease (analysis of covariance: control vs. levomethadone with and without heroine co-use: p < 0.0001, diamorphine vs. levomethadone with heroine co-use: p = 0.043, diamorphine vs. levomethadone without heroine co-use: p < 0.0001). According to these findings, methylation of the BDNF IV promoter showed the highest level in patients receiving levomethadone without heroine co-use (linear mixed model: control vs. levomethadone group without heroine co-use: p = 0.008, with heroin co-use: p = 0.050, diamorphine vs. levomethadone group with heroine co-use: p = 0.077 and without heroine co-use: p = 0.015.). For the first time, we show an epigenetic mechanism that may provide an explanation for mood destabilization in levomethadone maintenance treatment.

Plasma Brain-Derived Neurotrophic Factor Levels in Newborn Infants with Neonatal Abstinence Syndrome

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is a type of growth factor that promotes growth and survival of neurons. Fetal exposure to opiates can lead to postnatal withdrawal syndrome, which is referred as neonatal abstinence syndrome (NAS). Preclinical and clinical studies have shown an association between opiates exposure and alteration in BDNF expression in the brain and serum levels in adult. However, to date, there are no data available on the effects of opiate exposure on BDNF levels in infant who are exposed to opiates in utero and whether BDNF level may correlate with the severity of NAS.

OBJECTIVE

To compare plasma BDNF levels among NAS and non-NAS infants and to determine the correlation of BDNF levels and the severity of NAS.

METHODS

This is a prospective cohort study with no intervention involved. Infants ≥35 weeks of gestation were enrolled. BDNF level was measured using enzyme-linked immunosorbent assay technique from blood samples drawn within 48 h of life. The severity of NAS was determined by the length of hospital stay, number of medications required to treat NAS.

RESULTS

67 infants were enrolled, 34 NAS and 33 non-NAS. Mean gestational age did not differ between the two groups. Mean birth weight of NAS infants was significantly lower than the non-NAS infants (3,070 ± 523 vs. 3,340 ± 459 g, p = 0.028). Mean BDNF level in NAS group was 252.2 ± 91.6 ng/ml, significantly higher than 211.3 ± 66.3 ng/ml in the non-NAS group (p = 0.04). There were no differences in BDNF levels between NAS infants that required one medication vs. more than one medication (254 ± 91 vs. 218 ± 106 ng/ml, p = 0.47). There was no correlation between the BDNF levels and length of hospital stay (p = 0.68) among NAS infants. Overall, there were no significant correlations between BDNF levels and NAS scores except at around 15 h after admission (correlation 0.35, p = 0.045).

CONCLUSION

Plasma BDNF level was significantly increased in NAS infants during the first 48 h when compared to non-NAS infants. The correlations between plasma BDNF levels and the severity of NAS warrant further study. These results suggest that BDNF may play a neuromodulatory role during withdrawal after in utero opiate exposure.

Biochemical Diagnosis in Substance and Non-substance Addiction

An optimal biochemical marker for addiction would be some easily traced molecules in body specimens, which indicates indulgent addictive behaviors, or susceptibility to certain addictive stimuli. In this chapter, we discussed existing literature about possible biomarkers, and classified them into three categories: origin forms and metabolites of substances, markers from biochemical responses to certain addiction, and genetic and epigenetic biomarkers suggesting susceptibility to addiction. In every category, we examined studies concerning certain type of addiction one by one, with focuses mainly on opiates, psychostimulants, and pathological gambling. Several promising molecules were highlighted, including those of neurotrophic factors, inflammatory factors, and indicators of vascular injury, and genetic and epigenetic biomarkers such as serum miRNAs. DNA methylation signatures and signal nucleotide polymorphism of candidate gene underlying the addiction.

Altered Acoustic Startle Reflex, Prepulse Inhibition, and Peripheral Brain-Derived Neurotrophic Factor in Morphine Self-Administered Rats

BACKGROUND

Previous studies suggested that opiate withdrawal may increase anxiety and disrupt brain-derived neurotrophic factor function, but the effects of i.v. morphine self-administration on these measures remain unclear.

METHODS

Adult male Sprague-Dawley rats were implanted with a catheter in the jugular vein. After 1 week of recovery, the animals were allowed to self-administer either i.v. morphine (0.5 mg/kg per infusion, 4 h/d) or saline in the operant conditioning chambers. The acoustic startle reflex and prepulse inhibition were measured at a baseline and on self-administration days 1, 3, 5, and 7 (1- and 3-hour withdrawal). Blood samples were collected on self-administration days 3, 5, and 7 from separate cohorts of animals, and the levels of brain-derived neurotrophic factor and corticosterone were assayed using the enzyme-linked immunosorbent assay method.

RESULTS

Compared with the saline group, the morphine self-administration group showed hyper-locomotor activity and reduced defecation during the self-administration. The morphine self-administration increased acoustic startle reflex at 1-hour but not 3-hour withdrawal from morphine and disrupted prepulse inhibition at 3-hour but not 1-hour withdrawal. The blood brain-derived neurotrophic factor levels were decreased in the morphine self-administration group at self-administration days 3 and 5, while the corticosterone levels remained unchanged throughout the study.

CONCLUSIONS

The current findings suggest that spontaneous withdrawal from i.v. morphine self-administration may have transient effects on acoustic startle, sensorimotor gating, and peripheral brain-derived neurotrophic factor levels, and these changes may contribute to the adverse effects of opiate withdrawal.

Hypothalamic-pituitary-adrenal axis hyperactivity is associated with decreased brain-derived neurotrophic factor in female suicide attempters

INTRODUCTION

Both decreased levels of brain-derived neurotrophic factor (BDNF) and hypothalamic-pituitary-adrenal (HPA) axis dysregulation may be involved in the pathophysiology of suicidal behaviour, as well as cognitive symptoms of depression. Pre-clinical and clinical studies have shown interactions between HPA-axis activity and BDNF, but this has not been studied in a clinical cohort of suicidal subjects. The purpose of this study was, therefore, to investigate associations between HPA-axis activity and BDNF in suicide attempters. Furthermore, this study examined the relationship between the HPA-axis, BDNF, and cognitive symptoms in suicidal patients. Since previous data indicate gender-related differences in BDNF and the HPA axis, males and females were examined separately.

METHOD

Seventy-five recent suicide attempters (n = 41 females; n = 34 males) were enrolled in the study. The Dexamethasone Suppression Test (DST) was performed and BDNF in plasma were analysed. Patients were evaluated with the Comprehensive Psychopathological Rating Scale (CPRS) from which items 'Concentration difficulties' and 'Failing memory' were extracted.

RESULTS

Only among females, DST non-suppressors had significantly lower BDNF compared to DST suppressors (p = 0.022), and there was a significant correlation between post-DST serum cortisol at 8 a.m. and BDNF (rs = -0.437, p = 0.003). Concentration difficulties correlated significantly with post-DST cortisol in all patients (rs = 0.256, p = 0.035), in females (rs = 0.396, p = 0.015), and with BDNF in females (rs = -0.372, p = 0.020).

CONCLUSION

The findings suggest an inverse relationship between the HPA-axis and BDNF in female suicide attempters. Moreover, concentration difficulties may be associated with low BDNF and DST non-suppression in female suicide attempters.

Brain-derived neurotrophic factor serum levels in heroin-dependent patients after 26weeks of withdrawal

BACKGROUND

Brain-derived neurotrophic factor (BDNF) has been implicated in the pathophysiology of heroin dependence. BDNF expression is dramatically changed during drug withdrawal, and is associated with drug withdrawal syndrome. This study aimed to explore (1) alterations of BDNF serum levels in heroin-dependent patients after long term abstinence; and (2) the association between BDNF serum levels and protracted withdrawal syndrome.

METHOD

Fifty-three male heroin-dependent patients and fifty-two gender-matched healthy controls were enrolled in this study. We measured BDNF serum levels at baseline and 26 weeks after heroin abstinence. Moreover, protracted withdrawal symptoms, depression and anxiety symptoms were measured by Protracted Withdrawal Symptoms of Heroin-dependent patients (PWSHA), Self-rating Depression Scale (SDS) and Self-rating Anxiety Scale (SAS), respectively.

RESULT

We found that baseline BDNF serum levels were significantly lower in heroin-dependent patients compared to controls (p<0.01). There was also a significantly difference in BDNF serum levels among heroin-dependent patients at baseline and 26-week follow-up (p<0.01). The BDNF serum levels were not associated with age, BMI, years of education, age of initial use, or duration of use. Of the clinical symptoms measured, the change in BDNF serum levels from baseline to 26-week follow-up was negatively associated with the change in PWSHA scores (r = -0.44, p<0.01, see Table 2 and Figure 2 for details).

CONCLUSION

The results show that the BDNF serum levels in heroin-dependent patients are lower than those of healthy controls at baseline and increased after 26 weeks of abstinence, although the BDNF serum levels are still lower than those of the healthy controls. A negative correlation between the change in BDNF serum levels and protracted withdrawal symptoms was found but needs to be confirmed in further study. The results revealed that BDNF serum level is worth paying attention to in order to further investigate the possibility of it being a biomarker of treatment outcome for opiate dependence.

Serum brain-derived neurotrophic factor levels and psychotic symptoms in heroin dependence

OBJECTIVES

Psychotic symptoms are commonly observed among heroin users. Low serum brain-derived neurotrophic factor (BDNF) levels have been reported in schizophrenia and psychosis; however, studies assessing the relationship between serum BDNF levels and psychotic symptoms in heroin dependence are lacking.

METHOD

A total of 31 heroin-dependent patients who had never experienced psychotic symptoms during heroin consumption and 21 patients with a history of psychotic symptoms were consecutively recruited. We measured by enzyme-linked immunosorbent assay (ELISA) serum BDNF levels during early abstinence. A gender- and age-matched sample of healthy controls was also recruited and underwent measurement of BDNF.

RESULTS

BDNF levels were significantly lower in patients with psychotic symptoms than in those without psychotic symptoms (P<0.001). BDNF levels were not found to be correlated with sex, age, age of onset, duration of heroin use, average daily dose of heroin use, frequency of heroin use, SDS scores, BAI scores and BDI scores in the psychotic subsamples (all P>0.05).

CONCLUSIONS

Our findings suggest that heroin-dependent patients with psychotic symptoms share some of the neurotrophic insult that characterizes schizophrenia and psychosis.

The Effects of BDNF Val66Met Gene Polymorphism on Serum BDNF and Cognitive Function in Methamphetamine-Dependent Patients and Normal Controls: A Case-Control Study

Studies suggest that a functional polymorphism of the brain-derived neurotrophic factor gene (BDNF Val66Met) may contribute to methamphetamine dependence. We hypothesized that this polymorphism had a role in cognitive deficits in methamphetamine-dependent patients and in the relationship of serum BDNF with cognitive impairments. We conducted a case-control study by assessing 194 methamphetamine-dependent patients and 378 healthy volunteers without history of drug use on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the presence of the BDNF Val66Met polymorphism and serum BDNF levels. We showed no significant differences in genotype and allele distributions between the methamphetamine-dependent patients and controls. Some aspects of cognitive function significantly differed in the 2 groups. The serum BDNF levels in methamphetamine-dependent patients were significantly higher than those of the healthy controls. In the patients, partial correlation analysis showed a significant positive correlation between serum BDNF and the delayed memory index score. The RBANS scores showed statistically significant BDNF level × genotype interaction. Further regression analyses showed a significant positive association between BDNF levels and the RBANS total score, immediate memory or attention index among Val homozygote patients, whereas a significant negative association of BDNF levels with the RBANS total score, visuospatial/constructional, or language index was found among Met/Val heterozygous patients. We demonstrated significant impairment on some aspects of cognitive function and increased BDNF levels in methamphetamine-dependent patients as well as genotypic differences in the relationships between BDNF levels and RBANS scores on the BDNF Val66Met polymorphism only in these patients.

Functional alterations of astrocytes in mental disorders: pharmacological significance as a drug target

Astrocytes play an essential role in supporting brain functions in physiological and pathological states. Modulation of their pathophysiological responses have beneficial actions on nerve tissue injured by brain insults and neurodegenerative diseases, therefore astrocytes are recognized as promising targets for neuroprotective drugs. Recent investigations have identified several astrocytic mechanisms for modulating synaptic transmission and neural plasticity. These include altered expression of transporters for neurotransmitters, release of gliotransmitters and neurotrophic factors, and intercellular communication through gap junctions. Investigation of patients with mental disorders shows morphological and functional alterations in astrocytes. According to these observations, manipulation of astrocytic function by gene mutation and pharmacological tools reproduce mental disorder-like behavior in experimental animals. Some drugs clinically used for mental disorders affect astrocyte function. As experimental evidence shows their role in the pathogenesis of mental disorders, astrocytes have gained much attention as drug targets for mental disorders. In this paper, I review functional alterations of astrocytes in several mental disorders including schizophrenia, mood disorder, drug dependence, and neurodevelopmental disorders. The pharmacological significance of astrocytes in mental disorders is also discussed.

The BDNF Val66Met polymorphism and plasma brain-derived neurotrophic factor levels in Han Chinese heroin-dependent patients

BDNF and its gene polymorphism may be important in synaptic plasticity and neuron survival, and may become a key target in the physiopathology of long-term heroin use. Thus, we investigated the relationships between brain-derived neurotrophic factor (BDNF) plasma concentrations and the BDNF Val66Met nucleotide polymorphism (SNP) in heroin-dependent patients. The pretreatment expression levels of plasma BDNF and the BDNF Val66Met SNP in 172 heroin-dependent patients and 102 healthy controls were checked. BDNF levels were significantly lower in patients (F = 52.28, p < 0.0001), but the distribution of the SNP was not significantly different. Nor were plasma BDNF levels significantly different between Met/Met, Met/Val, and Val/Val carriers in each group, which indicated that the BDNF Val66Met SNP did not affect plasma BDNF levels in our participants. In heroin-dependent patients, plasma BDNF levels were negatively correlated with the length of heroin dependency. Long-term (>15 years) users had significantly lower plasma BDNF levels than did short-term (<5 years) users. We conclude that plasma BDNF concentration in habitual heroin users are not affected by BDNF Val66Met gene variants, but by the length of the heroin dependency.

Brain-derived neurotrophic factor and addiction: Pathological versus therapeutic effects on drug seeking

Many abused drugs lead to changes in endogenous brain-derived neurotrophic factor (BDNF) expression in neural circuits responsible for addictive behaviors. BDNF is a known molecular mediator of memory consolidation processes, evident at both behavioral and neurophysiological levels. Specific neural circuits are responsible for storing and executing drug-procuring motor programs, whereas other neural circuits are responsible for the active suppression of these "seeking" systems. These seeking-circuits are established as associations are formed between drug-associated cues and the conditioned responses they elicit. Such conditioned responses (e.g. drug seeking) can be diminished either through a passive weakening of seeking- circuits or an active suppression of those circuits through extinction. Extinction learning occurs when the association between cues and drug are violated, for example, by cue exposure without the drug present. Cue exposure therapy has been proposed as a therapeutic avenue for the treatment of addictions. Here we explore the role of BDNF in extinction circuits, compared to seeking-circuits that "incubate" over prolonged withdrawal periods. We begin by discussing the role of BDNF in extinction memory for fear and cocaine-seeking behaviors, where extinction circuits overlap in infralimbic prefrontal cortex (PFC). We highlight the ability of estrogen to promote BDNF-like effects in hippocampal-prefrontal circuits and consider the role of sex differences in extinction and incubation of drug-seeking behaviors. Finally, we examine how opiates and alcohol "break the mold" in terms of BDNF function in extinction circuits.