Neuroscience Letters 571 (2014) 61–65
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Neuroscience Letters journal homepage: www.elsevier.com/locate/neulet
Increased serum brain-derived neurotrophic factor levels during opiate withdrawal Jie Zhang a , XiangYang Zhang b,c,∗ , Hang Su a , JingYan Tao a , Ying Xie a , Bin Han a , YuLing Lu a , YouDan Wei a , HaiWei Sun a , Yue Wang a , WenXiu Wu a , ShengZhen Zou a , Haiyan Liang d , Anthony William Zoghbi e , WenJie Tang a , JinCai He a,∗∗ a
The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, PR China Beijing HuiLongGuan Hospital, Peking University, Beijing, PR China c Department of Psychiatry and Behavioral Sciences, Harris County Psychiatric Center, The University of Texas Health Science Center at Houston, Houston, TX, USA d Department of Neurology, Taizhou Municipal Hospital, Zhejiang, PR China e Department of Psychiatry, Columbia University, New York, NY, USA b
h i g h l i g h t s • • • •
We examined changes in the levels of serum BDNF during opiate withdrawal. Serum BDNF levels increased during opiate early withdrawal. Serum BDNF levels remained higher even after one month of abstinence. BDNF may play a critical role in the course of opiate addiction and withdrawal.
a r t i c l e
i n f o
Article history: Received 15 March 2014 Received in revised form 28 April 2014 Accepted 29 April 2014 Available online 5 May 2014 Keywords: Opiate Addiction Brain-derived neurotrophic factor Withdrawal
a b s t r a c t Brain-derived neurotrophic factor (BDNF) has been implicated in the pathophysiology of opiate addiction. Both increased and decreased serum BDNF levels have been reported in heroin addicts. Moreover, the role of BDNF in heroin-dependent patients during withdrawal has not been studied. This study aimed to explore the differences in serum BDNF levels of heroin addicts and healthy controls, and investigate the changes of serum BDNF levels in heroin addicts at baseline and at one month after heroin cessation. Seventy-two heroin-dependent patients and ninety age- and gender-matched healthy controls were enrolled in this study. We measured serum BDNF levels at baseline (both heroin addicts and healthy controls) and one month after heroin cessation (heroin addicts only). A total of 37 (51.4%) heroin addicts completed the one-month study. We found that baseline serum BDNF levels were significantly higher in heroin addicts compared to controls (F = 36.5, p = 0.001). There was no difference in serum BDNF levels among heroin addicts at baseline and one month after heroin cessation (F = 1.101, p = 0.301). These results indicate that BDNF may play a critical role in the course of opiate addiction and withdrawal. © 2014 Elsevier Ireland Ltd. All rights reserved.
1. Introduction
∗ Corresponding author at: Department of Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston, 1941 East Road, Houston, TX 77054, USA. ∗∗ Corresponding author at: Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, Zhejiang, PR China. Tel.: +86 577 55579363. E-mail addresses: [email protected] (X. Zhang), [email protected] (J. He). http://dx.doi.org/10.1016/j.neulet.2014.04.048 0304-3940/© 2014 Elsevier Ireland Ltd. All rights reserved.
The midbrain dopaminergic system is presumed to play a critical role in reward and addiction [28]. Opiates have been shown to indirectly activate (disinhibit) dopaminergic neurons in the ventral tegmental area (VTA) by inhibiting local GABAergic interneurons [18]. Brain-derived neurotrophic factor (BDNF) is one of the most abundant neurotrophic factors in the brain, and has a critical role in the survival and function of midbrain dopaminergic and cholinergic neurons [13,15]. BDNF has been reported to be involved in learning and memory, and synaptic plasticity [4,21,29]. Furthermore, several studies have demonstrated alterations of serum or
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plasma BDNF levels in drug abusers [8,19] and implicated BDNF in the development of addiction [12]. In preclinical studies, changes of BDNF expression in the VTA were found during chronic opiate administration or withdrawal [7,30]. Chronic morphine treatment leads to induction of tyrosine hydroxylase and reduction in the size of dopamine neurons in the VTA, both of which were prevented by intra-VTA infusion of BDNF [5,27]. There also appears to be a relationship between heroin dependence and BDNF genetic polymorphisms [16]. At this time, there have been two studies measuring levels of serum BDNF in opiate abusers; however, the results were contradictory [2,14]. In addition, there have been no studies of serum BDNF levels in heroin-dependent patients after cessation of heroin. In the present study, we compared serum BDNF levels of heroindependent patients during withdrawal and healthy controls in order to understand the relationship of BDNF and heroin use. 2. Materials and methods 2.1. Subjects Seventy-two Chinese heroin-dependent patients were recruited from Sanyang Detoxification Institute, which is located in Wenzhou city in the Zhejiang province. While in the institute, inpatients had no access to heroin, which allowed for rigid control of abstinence. Participants were included in the study based on the following criteria: age 18 years or older, fulfillment of the Diagnostics and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria for current heroin dependence, positive urine test for opiates upon admission, heroin abstinence for 1–7 days (period between enrollment and last drug use), and signed informed consent. Subjects were excluded if they were seropositive for HIV, had serious medical illnesses that required pharmacological treatment, or met the DSM-IV criteria for axis I psychiatric disorder or drug dependence other than heroin or nicotine, which were assessed and ruled out by a clinical psychiatrist. In order to manage withdrawal symptoms, patients were given initial dosages of methadone in the range of 30–40 mg/day and then slowly tapered by 5 mg/day. Methadone was administrated orally and once daily. The patients took no other medications during heroin withdrawal. Ninety normal controls were randomly selected from healthy subjects who visited the first affiliated hospital of Wenzhou medical university for regular medical examination. Healthy subjects had no self-reported family psychiatric history and no medication history. This study was approved by the Human Research and Ethics Committee of Wenzhou Medical University. Written informed consent was obtained from all subjects after a detailed description of the study.
Table 1 Characteristics of heroin users and normal controls. Characteristics
Heroin users (n = 72)
Normal controls (n = 90)
Statistic (p value)
Age (years) Male/female (n) Education (years) BMI (kg/m2 )
35.3 ± 7.9 65/7 7.1 ± 2.3 20.8 ± 2.4
32.9 ± 9.9 77/13 13.9 ± 1.9 21.4 ± 2.3
−1.72 (0.087) 0.82 (0.36) −10.59 (0.01) 1.55 (0.124)
Note: BMI = body mass index. Bold value indicates p < 0.05.
blood samples were collected between 8 and 10 AM in order to limit a possible rhythm variance bias. At baseline (recruited heroin subjects were abstinent for less than 7 days, with an average abstinent period of 4.28 ± 1.7 days), all 72 heroin subjects completed the measurement. However, at the end of the one-month endpoint, only 37(51.4%) heroin patients (with an average abstinent period of 29.2 ± 2.1 days) completed the measurement. 35(48.6%) heroin users dropped out due to discharge or referral. 5 ml of blood was collected and allowed to clot at room temperature, and the blood was centrifuged at 3500 rpm for 10 min immediately. Serum was obtained, and then stored at −80 ◦ C until it was thawed for assay. Serum BDNF levels were measured using DuoSet ELISA Development System (Catalog number DY248, R&D Systems, USA). All measurements were conducted by trained operators blind to the research design according to the manufacturer’s instruction. All assays were performed in duplicate and expressed as pg/ml. The detection range of this assay was 20–4000 pg/ml. The intra-assay and inter-assay coefficients were 0.05).
4. Discussion To our knowledge, this is the first study to demonstrate significantly increased serum BDNF levels in heroin-dependent patients during both early withdrawal (1–7 days) and one month after heroin cessation when compared to healthy controls. The results of this study support the notion that BDNF might play a critical role in opiate addiction and withdrawal. To date, only two studies have investigated serum BDNF levels among heroin users, however, the results were contradictory. In the first study, Angelucci et al. found decreased serum BDNF levels in heroin-dependent patients [2]. Contrary to the results reported by Angelucci and colleagues, Heberlein et al. reported elevated serum BDNF levels in heroin-dependent patients during opiate maintenance treatment [14], which was in line with our results. The relatively small sample size (n = 15) in Angelucci and colleagues’ investigation may have contributed to the contradictory results. In addition, factors such as nicotine use [17], alcohol consumption [17], depression [23], and stress [22] have all been reported to influence serum BDNF levels. Therefore, these factors may also explain part of the discrepancy of the results. The results of our investigation are in line with a preclinical study reporting elevated BDNF protein and mRNA expression in the VTA after chronic heroin treatment. The study also demonstrated a shift from a dopamine-independent to a dopamine-dependent opiate reward system caused by the infusion of BNDF into the VTA [30]. Moreover, BDNF has been shown to play an important role in the opiate-induced plasticity of noradrenergic locus coeruleus (LC) neurons [1], which is implicated in the pathogenesis of opiate dependence and withdrawal [24]. This evidence suggests that elevated BDNF levels may be part of the mechanism underlying the course of opiate addiction. Additionally, increased BDNF expression may counteract the effect of chronic opiate use on neurons. For example, animal studies have shown that chronic opiate administration contributes to biochemical and morphological changes in VTA, and some of these changes in VTA can be prevented or reversed by the infusion of BDNF into this brain region [5,27]. Therefore, it is likely that increased BDNF expression occurs as a compensatory response to neuronal insult. Serum BDNF levels have now been shown to be elevated during chronic opiate use [13], during early withdrawal (days 1–7), and one month after heroin cessation. These findings suggest that BDNF may serve as a candidate biomarker for heroin addiction and withdrawal. However, Vargas-Perez and colleagues did not find an
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elevation in serum BDNF levels on the 15th day after withdrawal from 8 days of heroin administration compared with the control drug-naive rats [30]. Heroin dosage differences (0.5 mg/kg in rats vs 420 mg average in humans) and average length of heroin exposure (8 days in rats versus 97.2 months in humans) may account for the difference in our findings. Due to the constraints of a onemonth endpoint, we cannot rule out the possibility that human serum BDNF levels in abstinent heroin subjects may decrease with more time. Therefore, a longer follow-up period study will be necessary to better categorize the relationship between the changes of serum BDNF levels and the length of abstinence and to confirm the role of BDNF as a biomarker for opiate addiction and withdrawal. Moreover, we measured peripheral serum BDNF levels as opposed to brain BDNF levels, which may also contribute to this inconsistent result. We also found that age had some effect on serum BDNF levels in the heroin group. The older the age of heroin-dependent patients, the higher the BDNF serum levels (ˇ = 0.244, t = 2.103, p = 0.039). Several lines of work are consistent with our finding. For example, an age-dependent increase in serum BDNF levels has been reported for women but not men [6,10]. However, in present study, the majority of subjects were males and the sample size of females was relatively small. Therefore, further studies with equal proportions of males and females will be necessary to elucidate the effects of age and gender on the BDNF serum levels. There are several limitations of our study. First, we measured BDNF levels in the serum and not in the brain. At this point, it is not clear whether changes in serum BDNF levels stem from alterations of BNDF levels in the periphery, brain, or both. The main source of serum BDNF is from platelets, which appear to bind, store and release BDNF upon activation or via the clotting process [11,31]. Peripheral BDNF levels may reflect central BDNF levels as neurons and platelets both originate from neural crest origin [26]. In addition, a previous study showed that reduced platelet BDNF contents as circulating stored BDNF is associated with lower serum BDNF level in patients with major depression [20]. However, we did not measure platelet BDNF level in our present study, which is one of the main limitations of this study, and should be remedied in the further investigation. Second, an important limitation is that we did not collect any clinical measures of craving, or abstinence symptoms, which may be the potentially associated with BDNF levels and should be examined in the future investigation. Third, opiate users were not evaluated using a Structured Clinical Interview for DSM-IV (SCID) to rule out the comorbid psychiatric disorders, only by the clinical psychiatrist. Forth, the short follow-up period may limit the interpretation of our results. In future research, a longer follow-up period will be needed to clarify the relationship between serum BDNF levels and the length of abstinence. Fifth, in the institute, in order to manage withdrawal symptoms, all the heroin-dependent patients were managed with methadone during the first week of withdrawal from heroin. A study of BDNF genetic variability suggests that individuals with certain polymorphisms in the BDNF genomic region have an increased risk of poor response to methadone treatment which may affect the withdrawal process [9]. In addition, methadone, which is similar to heroin, may also have an effect on serum BDNF levels. In summary, we observed that serum BDNF levels were increased in heroin-dependent patients during early withdrawal when compared to healthy controls and remained steady even after one month of abstinence. These results suggest that increased serum BDNF levels may be associated with the pathophysiology of opiate addiction and withdrawal. Further longer follow-up period study is necessary to elucidate the role of BDNF as a potential biological marker in opiate addiction and withdrawal.
Acknowledgements This work was funded by the grant from National Key Technology R&D Program in the 11th Five year Plan of China (2009BAI77B06) and Wenzhou Municipal Sci-Tech Bureau Program (H20100021). These sources had no further role in study design, data collection and analysis, decision to publish, or preparation of the article. References [1] S. Akbarian, M. Rios, R.J. Liu, S.J. Gold, H.F. Fong, S. Zeiler, V. Coppola, L. Tessarollo, K.R. Jones, E.J. Nestler, G.K. Aghajanian, R. Jaenisch, Brain-derived neurotrophic factor is essential for opiate-induced plasticity of noradrenergic neurons, J. Neurosci.: Off. J. Soc. Neurosci. 22 (2002) 4153–4162. [2] F. Angelucci, V. Ricci, M. Pomponi, G. Conte, A.A. Mathe, P. Attilio Tonali, P. Bria, Chronic heroin and cocaine abuse is associated with decreased serum concentrations of the nerve growth factor and brain-derived neurotrophic factor, J. Psychopharmacol. (Oxford, England) 21 (2007) 820–825. [3] A.T. Beck, W.Y. Rial, K. Rickels, Short form of depression inventory: crossvalidation, Psychol. Rep. 34 (1974) 1184–1186. [4] P. Bekinschtein, M. Cammarota, I. Izquierdo, J.H. Medina, BDNF and memory formation and storage, Neuroscientist: Rev. J. Neurobiol. Neurol. Psychiatry 14 (2008) 147–156. [5] M.T. Berhow, D.S. Russell, R.Z. Terwilliger, D. Beitner-Johnson, D.W. Self, R.M. Lindsay, E.J. Nestler, Influence of neurotrophic factors on morphine- and cocaine-induced biochemical changes in the mesolimbic dopamine system, Neuroscience 68 (1995) 969–979. [6] B.A. Bus, M.L. Molendijk, B.J. Penninx, J.K. Buitelaar, G. Kenis, J. Prickaerts, B.M. Elzinga, R.C. Voshaar, Determinants of serum brain-derived neurotrophic factor, Psychoneuroendocrinology 36 (2011) 228–239. [7] N.N. Chu, W. Xia, P. Yu, L. Hu, R. Zhang, C.L. Cui, Chronic morphine-induced neuronal morphological changes in the ventral tegmental area in rats are reversed by electroacupuncture treatment, Addict. Biol. 13 (2008) 47–51. [8] M. Corominas-Roso, C. Roncero, F.J. Eiroa-Orosa, B. Gonzalvo, L. Grau-Lopez, M. Ribases, L. Rodriguez-Cintas, C. Sanchez-Mora, J.A. Ramos-Quiroga, M. Casas, Brain-derived neurotrophic factor serum levels in cocaine-dependent patients during early abstinence, Eur. Neuropsychopharmacol.: J. Eur. Coll. Neuropsychopharmacol. 23 (2013) 1078–1084. [9] R. de Cid, F. Fonseca, M. Gratacos, F. Gutierrez, R. Martin-Santos, X. Estivill, M. Torrens, BDNF variability in opioid addicts and response to methadone treatment: preliminary findings, Genes Brain Behav. 7 (2008) 515–522. [10] B. Elfving, H.N. Buttenschon, L. Foldager, P.H. Poulsen, J.H. Andersen, M.B. Grynderup, A.M. Hansen, H.A. Kolstad, L. Kaerlev, S. Mikkelsen, J.F. Thomsen, A.D. Borglum, G. Wegener, O. Mors, Depression, the Val66Met polymorphism, age, and gender influence the serum BDNF level, J. Psychiatr. Res. 46 (2012) 1118–1125. [11] H. Fujimura, C.A. Altar, R. Chen, T. Nakamura, T. Nakahashi, J. Kambayashi, B. Sun, N.N. Tandon, Brain-derived neurotrophic factor is stored in human platelets and released by agonist stimulation, Thromb. Haemost. 87 (2002) 728–734. [12] U.E. Ghitza, H. Zhai, P. Wu, M. Airavaara, Y. Shaham, L. Lu, Role of BDNF and GDNF in drug reward and relapse: a review, Neurosci. Biobehav. Rev. 35 (2010) 157–171. [13] D.H. Ha, R.T. Robertson, M. Roshanaei, J.H. Weiss, Enhanced survival and morphological features of basal forebrain cholinergic neurons in vitro: role of neurotrophins and other potential cortically derived cholinergic trophic factors, J. Comp. Neurol. 406 (1999) 156–170. [14] A. Heberlein, K.M. Dursteler-MacFarland, B. Lenz, H. Frieling, M. Grosch, D. Bonsch, J. Kornhuber, G.A. Wiesbeck, S. Bleich, T. Hillemacher, Serum levels of BDNF are associated with craving in opiate-dependent patients, J. Psychopharmacol. (Oxford, England) 25 (2011) 1480–1484. [15] C. Hyman, M. Hofer, Y.A. Barde, M. Juhasz, G.D. Yancopoulos, S.P. Squinto, R.M. Lindsay, BDNF is a neurotrophic factor for dopaminergic neurons of the substantia nigra, Nature 350 (1991) 230–232. [16] W. Jia, J.G. Shi, B. Wu, L. Ao, R. Zhang, Y.S. Zhu, Polymorphisms of brain-derived neurotrophic factor associated with heroin dependence, Neurosci. Lett. 495 (2011) 221–224. [17] K.H. Joe, Y.K. Kim, T.S. Kim, S.W. Roh, S.W. Choi, Y.B. Kim, H.J. Lee, D.J. Kim, Decreased plasma brain-derived neurotrophic factor levels in patients with alcohol dependence, Alcohol. Clin. Exp. Res. 31 (2007) 1833–1838. [18] S.W. Johnson, R.A. North, Opioids excite dopamine neurons by hyperpolarization of local interneurons, J. Neurosci.: Off. J. Soc. Neurosci. 12 (1992) 483–488. [19] D.J. Kim, S. Roh, Y. Kim, S.J. Yoon, H.K. Lee, C.S. Han, Y.K. Kim, High concentrations of plasma brain-derived neurotrophic factor in methamphetamine users, Neurosci. Lett. 388 (2005) 112–115. [20] B.H. Lee, Y.K. Kim, Reduced platelet BDNF level in patients with major depression, Prog. Neuro-psychopharmacol. Biol. Psychiatry 33 (2009) 849–853. [21] Y. Lu, K. Christian, B. Lu, BDNF: a key regulator for protein synthesis-dependent LTP and long-term memory? Neurobiol. Learn. Mem. 89 (2008) 312–323. [22] M. Mitoma, R. Yoshimura, A. Sugita, W. Umene, H. Hori, H. Nakano, N. Ueda, J. Nakamura, Stress at work alters serum brain-derived neurotrophic factor (BDNF) levels and plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) levels in
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[23]
[24] [25]
[26]
healthy volunteers: BDNF and MHPG as possible biological markers of mental stress? Prog. Neuro-psychopharmacol. Biol. Psychiatry 32 (2008) 679–685. M.L. Molendijk, B.A. Bus, P. Spinhoven, B.W. Penninx, G. Kenis, J. Prickaerts, R.C. Voshaar, B.M. Elzinga, Serum levels of brain-derived neurotrophic factor in major depressive disorder: state-trait issues, clinical features and pharmacological treatment, Mol. Psychiatry 16 (2011) 1088–1095. E.J. Nestler, G.K. Aghajanian, Molecular and cellular basis of addiction, Science (New York, NY) 278 (1997) 58–63. A. Osman, J. Hoffman, F.X. Barrios, B.A. Kopper, J.L. Breitenstein, S.K. Hahn, Factor structure, reliability, and validity of the Beck anxiety inventory in adolescent psychiatric inpatients, J. Clin. Psychol. 58 (2002) 443–456. A.G. Pearse, The common peptides and the cytochemistry of their cells of origin, Basic Appl. Histochem. 24 (1980) 63–73.
65
[27] L. Sklair-Tavron, W.X. Shi, S.B. Lane, H.W. Harris, B.S. Bunney, E.J. Nestler, Chronic morphine induces visible changes in the morphology of mesolimbic dopamine neurons, Proc. Natl. Acad. Sci. U.S.A. 93 (1996) 11202–11207. [28] R. Spanagel, F. Weiss, The dopamine hypothesis of reward: past and current status, Trends Neurosci. 22 (1999) 521–527. [29] H. Thoenen, Neurotrophins and neuronal plasticity, Science (New York, NY) 270 (1995) 593–598. [30] H. Vargas-Perez, A.K.R. Ting, C.H. Walton, D.M. Hansen, R. Razavi, L. Clarke, M.R. Bufalino, D.W. Allison, S.C. Steffensen, D. van der Kooy, Ventral tegmental area BDNF induces an opiate-dependent-like reward state in naive rats, Science (New York, NY) 324 (2009) 1732–1734. [31] H. Yamamoto, M.E. Gurney, Human platelets contain brain-derived neurotrophic factor, J. Neurosci.: Off. J. Soc. Neurosci. 10 (1990) 3469–3478.
Contents lists available at ScienceDirect
Neuroscience Letters journal homepage: www.elsevier.com/locate/neulet
Increased serum brain-derived neurotrophic factor levels during opiate withdrawal Jie Zhang a , XiangYang Zhang b,c,∗ , Hang Su a , JingYan Tao a , Ying Xie a , Bin Han a , YuLing Lu a , YouDan Wei a , HaiWei Sun a , Yue Wang a , WenXiu Wu a , ShengZhen Zou a , Haiyan Liang d , Anthony William Zoghbi e , WenJie Tang a , JinCai He a,∗∗ a
The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, PR China Beijing HuiLongGuan Hospital, Peking University, Beijing, PR China c Department of Psychiatry and Behavioral Sciences, Harris County Psychiatric Center, The University of Texas Health Science Center at Houston, Houston, TX, USA d Department of Neurology, Taizhou Municipal Hospital, Zhejiang, PR China e Department of Psychiatry, Columbia University, New York, NY, USA b
h i g h l i g h t s • • • •
We examined changes in the levels of serum BDNF during opiate withdrawal. Serum BDNF levels increased during opiate early withdrawal. Serum BDNF levels remained higher even after one month of abstinence. BDNF may play a critical role in the course of opiate addiction and withdrawal.
a r t i c l e
i n f o
Article history: Received 15 March 2014 Received in revised form 28 April 2014 Accepted 29 April 2014 Available online 5 May 2014 Keywords: Opiate Addiction Brain-derived neurotrophic factor Withdrawal
a b s t r a c t Brain-derived neurotrophic factor (BDNF) has been implicated in the pathophysiology of opiate addiction. Both increased and decreased serum BDNF levels have been reported in heroin addicts. Moreover, the role of BDNF in heroin-dependent patients during withdrawal has not been studied. This study aimed to explore the differences in serum BDNF levels of heroin addicts and healthy controls, and investigate the changes of serum BDNF levels in heroin addicts at baseline and at one month after heroin cessation. Seventy-two heroin-dependent patients and ninety age- and gender-matched healthy controls were enrolled in this study. We measured serum BDNF levels at baseline (both heroin addicts and healthy controls) and one month after heroin cessation (heroin addicts only). A total of 37 (51.4%) heroin addicts completed the one-month study. We found that baseline serum BDNF levels were significantly higher in heroin addicts compared to controls (F = 36.5, p = 0.001). There was no difference in serum BDNF levels among heroin addicts at baseline and one month after heroin cessation (F = 1.101, p = 0.301). These results indicate that BDNF may play a critical role in the course of opiate addiction and withdrawal. © 2014 Elsevier Ireland Ltd. All rights reserved.
1. Introduction
∗ Corresponding author at: Department of Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston, 1941 East Road, Houston, TX 77054, USA. ∗∗ Corresponding author at: Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, Zhejiang, PR China. Tel.: +86 577 55579363. E-mail addresses: [email protected] (X. Zhang), [email protected] (J. He). http://dx.doi.org/10.1016/j.neulet.2014.04.048 0304-3940/© 2014 Elsevier Ireland Ltd. All rights reserved.
The midbrain dopaminergic system is presumed to play a critical role in reward and addiction [28]. Opiates have been shown to indirectly activate (disinhibit) dopaminergic neurons in the ventral tegmental area (VTA) by inhibiting local GABAergic interneurons [18]. Brain-derived neurotrophic factor (BDNF) is one of the most abundant neurotrophic factors in the brain, and has a critical role in the survival and function of midbrain dopaminergic and cholinergic neurons [13,15]. BDNF has been reported to be involved in learning and memory, and synaptic plasticity [4,21,29]. Furthermore, several studies have demonstrated alterations of serum or
62
J. Zhang et al. / Neuroscience Letters 571 (2014) 61–65
plasma BDNF levels in drug abusers [8,19] and implicated BDNF in the development of addiction [12]. In preclinical studies, changes of BDNF expression in the VTA were found during chronic opiate administration or withdrawal [7,30]. Chronic morphine treatment leads to induction of tyrosine hydroxylase and reduction in the size of dopamine neurons in the VTA, both of which were prevented by intra-VTA infusion of BDNF [5,27]. There also appears to be a relationship between heroin dependence and BDNF genetic polymorphisms [16]. At this time, there have been two studies measuring levels of serum BDNF in opiate abusers; however, the results were contradictory [2,14]. In addition, there have been no studies of serum BDNF levels in heroin-dependent patients after cessation of heroin. In the present study, we compared serum BDNF levels of heroindependent patients during withdrawal and healthy controls in order to understand the relationship of BDNF and heroin use. 2. Materials and methods 2.1. Subjects Seventy-two Chinese heroin-dependent patients were recruited from Sanyang Detoxification Institute, which is located in Wenzhou city in the Zhejiang province. While in the institute, inpatients had no access to heroin, which allowed for rigid control of abstinence. Participants were included in the study based on the following criteria: age 18 years or older, fulfillment of the Diagnostics and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria for current heroin dependence, positive urine test for opiates upon admission, heroin abstinence for 1–7 days (period between enrollment and last drug use), and signed informed consent. Subjects were excluded if they were seropositive for HIV, had serious medical illnesses that required pharmacological treatment, or met the DSM-IV criteria for axis I psychiatric disorder or drug dependence other than heroin or nicotine, which were assessed and ruled out by a clinical psychiatrist. In order to manage withdrawal symptoms, patients were given initial dosages of methadone in the range of 30–40 mg/day and then slowly tapered by 5 mg/day. Methadone was administrated orally and once daily. The patients took no other medications during heroin withdrawal. Ninety normal controls were randomly selected from healthy subjects who visited the first affiliated hospital of Wenzhou medical university for regular medical examination. Healthy subjects had no self-reported family psychiatric history and no medication history. This study was approved by the Human Research and Ethics Committee of Wenzhou Medical University. Written informed consent was obtained from all subjects after a detailed description of the study.
Table 1 Characteristics of heroin users and normal controls. Characteristics
Heroin users (n = 72)
Normal controls (n = 90)
Statistic (p value)
Age (years) Male/female (n) Education (years) BMI (kg/m2 )
35.3 ± 7.9 65/7 7.1 ± 2.3 20.8 ± 2.4
32.9 ± 9.9 77/13 13.9 ± 1.9 21.4 ± 2.3
−1.72 (0.087) 0.82 (0.36) −10.59 (0.01) 1.55 (0.124)
Note: BMI = body mass index. Bold value indicates p < 0.05.
blood samples were collected between 8 and 10 AM in order to limit a possible rhythm variance bias. At baseline (recruited heroin subjects were abstinent for less than 7 days, with an average abstinent period of 4.28 ± 1.7 days), all 72 heroin subjects completed the measurement. However, at the end of the one-month endpoint, only 37(51.4%) heroin patients (with an average abstinent period of 29.2 ± 2.1 days) completed the measurement. 35(48.6%) heroin users dropped out due to discharge or referral. 5 ml of blood was collected and allowed to clot at room temperature, and the blood was centrifuged at 3500 rpm for 10 min immediately. Serum was obtained, and then stored at −80 ◦ C until it was thawed for assay. Serum BDNF levels were measured using DuoSet ELISA Development System (Catalog number DY248, R&D Systems, USA). All measurements were conducted by trained operators blind to the research design according to the manufacturer’s instruction. All assays were performed in duplicate and expressed as pg/ml. The detection range of this assay was 20–4000 pg/ml. The intra-assay and inter-assay coefficients were 0.05).
4. Discussion To our knowledge, this is the first study to demonstrate significantly increased serum BDNF levels in heroin-dependent patients during both early withdrawal (1–7 days) and one month after heroin cessation when compared to healthy controls. The results of this study support the notion that BDNF might play a critical role in opiate addiction and withdrawal. To date, only two studies have investigated serum BDNF levels among heroin users, however, the results were contradictory. In the first study, Angelucci et al. found decreased serum BDNF levels in heroin-dependent patients [2]. Contrary to the results reported by Angelucci and colleagues, Heberlein et al. reported elevated serum BDNF levels in heroin-dependent patients during opiate maintenance treatment [14], which was in line with our results. The relatively small sample size (n = 15) in Angelucci and colleagues’ investigation may have contributed to the contradictory results. In addition, factors such as nicotine use [17], alcohol consumption [17], depression [23], and stress [22] have all been reported to influence serum BDNF levels. Therefore, these factors may also explain part of the discrepancy of the results. The results of our investigation are in line with a preclinical study reporting elevated BDNF protein and mRNA expression in the VTA after chronic heroin treatment. The study also demonstrated a shift from a dopamine-independent to a dopamine-dependent opiate reward system caused by the infusion of BNDF into the VTA [30]. Moreover, BDNF has been shown to play an important role in the opiate-induced plasticity of noradrenergic locus coeruleus (LC) neurons [1], which is implicated in the pathogenesis of opiate dependence and withdrawal [24]. This evidence suggests that elevated BDNF levels may be part of the mechanism underlying the course of opiate addiction. Additionally, increased BDNF expression may counteract the effect of chronic opiate use on neurons. For example, animal studies have shown that chronic opiate administration contributes to biochemical and morphological changes in VTA, and some of these changes in VTA can be prevented or reversed by the infusion of BDNF into this brain region [5,27]. Therefore, it is likely that increased BDNF expression occurs as a compensatory response to neuronal insult. Serum BDNF levels have now been shown to be elevated during chronic opiate use [13], during early withdrawal (days 1–7), and one month after heroin cessation. These findings suggest that BDNF may serve as a candidate biomarker for heroin addiction and withdrawal. However, Vargas-Perez and colleagues did not find an
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elevation in serum BDNF levels on the 15th day after withdrawal from 8 days of heroin administration compared with the control drug-naive rats [30]. Heroin dosage differences (0.5 mg/kg in rats vs 420 mg average in humans) and average length of heroin exposure (8 days in rats versus 97.2 months in humans) may account for the difference in our findings. Due to the constraints of a onemonth endpoint, we cannot rule out the possibility that human serum BDNF levels in abstinent heroin subjects may decrease with more time. Therefore, a longer follow-up period study will be necessary to better categorize the relationship between the changes of serum BDNF levels and the length of abstinence and to confirm the role of BDNF as a biomarker for opiate addiction and withdrawal. Moreover, we measured peripheral serum BDNF levels as opposed to brain BDNF levels, which may also contribute to this inconsistent result. We also found that age had some effect on serum BDNF levels in the heroin group. The older the age of heroin-dependent patients, the higher the BDNF serum levels (ˇ = 0.244, t = 2.103, p = 0.039). Several lines of work are consistent with our finding. For example, an age-dependent increase in serum BDNF levels has been reported for women but not men [6,10]. However, in present study, the majority of subjects were males and the sample size of females was relatively small. Therefore, further studies with equal proportions of males and females will be necessary to elucidate the effects of age and gender on the BDNF serum levels. There are several limitations of our study. First, we measured BDNF levels in the serum and not in the brain. At this point, it is not clear whether changes in serum BDNF levels stem from alterations of BNDF levels in the periphery, brain, or both. The main source of serum BDNF is from platelets, which appear to bind, store and release BDNF upon activation or via the clotting process [11,31]. Peripheral BDNF levels may reflect central BDNF levels as neurons and platelets both originate from neural crest origin [26]. In addition, a previous study showed that reduced platelet BDNF contents as circulating stored BDNF is associated with lower serum BDNF level in patients with major depression [20]. However, we did not measure platelet BDNF level in our present study, which is one of the main limitations of this study, and should be remedied in the further investigation. Second, an important limitation is that we did not collect any clinical measures of craving, or abstinence symptoms, which may be the potentially associated with BDNF levels and should be examined in the future investigation. Third, opiate users were not evaluated using a Structured Clinical Interview for DSM-IV (SCID) to rule out the comorbid psychiatric disorders, only by the clinical psychiatrist. Forth, the short follow-up period may limit the interpretation of our results. In future research, a longer follow-up period will be needed to clarify the relationship between serum BDNF levels and the length of abstinence. Fifth, in the institute, in order to manage withdrawal symptoms, all the heroin-dependent patients were managed with methadone during the first week of withdrawal from heroin. A study of BDNF genetic variability suggests that individuals with certain polymorphisms in the BDNF genomic region have an increased risk of poor response to methadone treatment which may affect the withdrawal process [9]. In addition, methadone, which is similar to heroin, may also have an effect on serum BDNF levels. In summary, we observed that serum BDNF levels were increased in heroin-dependent patients during early withdrawal when compared to healthy controls and remained steady even after one month of abstinence. These results suggest that increased serum BDNF levels may be associated with the pathophysiology of opiate addiction and withdrawal. Further longer follow-up period study is necessary to elucidate the role of BDNF as a potential biological marker in opiate addiction and withdrawal.
Acknowledgements This work was funded by the grant from National Key Technology R&D Program in the 11th Five year Plan of China (2009BAI77B06) and Wenzhou Municipal Sci-Tech Bureau Program (H20100021). These sources had no further role in study design, data collection and analysis, decision to publish, or preparation of the article. References [1] S. Akbarian, M. Rios, R.J. Liu, S.J. Gold, H.F. Fong, S. Zeiler, V. Coppola, L. Tessarollo, K.R. Jones, E.J. Nestler, G.K. Aghajanian, R. Jaenisch, Brain-derived neurotrophic factor is essential for opiate-induced plasticity of noradrenergic neurons, J. Neurosci.: Off. J. Soc. Neurosci. 22 (2002) 4153–4162. [2] F. Angelucci, V. Ricci, M. Pomponi, G. Conte, A.A. Mathe, P. Attilio Tonali, P. Bria, Chronic heroin and cocaine abuse is associated with decreased serum concentrations of the nerve growth factor and brain-derived neurotrophic factor, J. Psychopharmacol. (Oxford, England) 21 (2007) 820–825. [3] A.T. Beck, W.Y. Rial, K. Rickels, Short form of depression inventory: crossvalidation, Psychol. Rep. 34 (1974) 1184–1186. [4] P. Bekinschtein, M. Cammarota, I. Izquierdo, J.H. Medina, BDNF and memory formation and storage, Neuroscientist: Rev. J. Neurobiol. Neurol. Psychiatry 14 (2008) 147–156. [5] M.T. Berhow, D.S. Russell, R.Z. Terwilliger, D. Beitner-Johnson, D.W. Self, R.M. Lindsay, E.J. Nestler, Influence of neurotrophic factors on morphine- and cocaine-induced biochemical changes in the mesolimbic dopamine system, Neuroscience 68 (1995) 969–979. [6] B.A. Bus, M.L. Molendijk, B.J. Penninx, J.K. Buitelaar, G. Kenis, J. Prickaerts, B.M. Elzinga, R.C. Voshaar, Determinants of serum brain-derived neurotrophic factor, Psychoneuroendocrinology 36 (2011) 228–239. [7] N.N. Chu, W. Xia, P. Yu, L. Hu, R. Zhang, C.L. Cui, Chronic morphine-induced neuronal morphological changes in the ventral tegmental area in rats are reversed by electroacupuncture treatment, Addict. Biol. 13 (2008) 47–51. [8] M. Corominas-Roso, C. Roncero, F.J. Eiroa-Orosa, B. Gonzalvo, L. Grau-Lopez, M. Ribases, L. Rodriguez-Cintas, C. Sanchez-Mora, J.A. Ramos-Quiroga, M. Casas, Brain-derived neurotrophic factor serum levels in cocaine-dependent patients during early abstinence, Eur. Neuropsychopharmacol.: J. Eur. Coll. Neuropsychopharmacol. 23 (2013) 1078–1084. [9] R. de Cid, F. Fonseca, M. Gratacos, F. Gutierrez, R. Martin-Santos, X. Estivill, M. Torrens, BDNF variability in opioid addicts and response to methadone treatment: preliminary findings, Genes Brain Behav. 7 (2008) 515–522. [10] B. Elfving, H.N. Buttenschon, L. Foldager, P.H. Poulsen, J.H. Andersen, M.B. Grynderup, A.M. Hansen, H.A. Kolstad, L. Kaerlev, S. Mikkelsen, J.F. Thomsen, A.D. Borglum, G. Wegener, O. Mors, Depression, the Val66Met polymorphism, age, and gender influence the serum BDNF level, J. Psychiatr. Res. 46 (2012) 1118–1125. [11] H. Fujimura, C.A. Altar, R. Chen, T. Nakamura, T. Nakahashi, J. Kambayashi, B. Sun, N.N. Tandon, Brain-derived neurotrophic factor is stored in human platelets and released by agonist stimulation, Thromb. Haemost. 87 (2002) 728–734. [12] U.E. Ghitza, H. Zhai, P. Wu, M. Airavaara, Y. Shaham, L. Lu, Role of BDNF and GDNF in drug reward and relapse: a review, Neurosci. Biobehav. Rev. 35 (2010) 157–171. [13] D.H. Ha, R.T. Robertson, M. Roshanaei, J.H. Weiss, Enhanced survival and morphological features of basal forebrain cholinergic neurons in vitro: role of neurotrophins and other potential cortically derived cholinergic trophic factors, J. Comp. Neurol. 406 (1999) 156–170. [14] A. Heberlein, K.M. Dursteler-MacFarland, B. Lenz, H. Frieling, M. Grosch, D. Bonsch, J. Kornhuber, G.A. Wiesbeck, S. Bleich, T. Hillemacher, Serum levels of BDNF are associated with craving in opiate-dependent patients, J. Psychopharmacol. (Oxford, England) 25 (2011) 1480–1484. [15] C. Hyman, M. Hofer, Y.A. Barde, M. Juhasz, G.D. Yancopoulos, S.P. Squinto, R.M. Lindsay, BDNF is a neurotrophic factor for dopaminergic neurons of the substantia nigra, Nature 350 (1991) 230–232. [16] W. Jia, J.G. Shi, B. Wu, L. Ao, R. Zhang, Y.S. Zhu, Polymorphisms of brain-derived neurotrophic factor associated with heroin dependence, Neurosci. Lett. 495 (2011) 221–224. [17] K.H. Joe, Y.K. Kim, T.S. Kim, S.W. Roh, S.W. Choi, Y.B. Kim, H.J. Lee, D.J. Kim, Decreased plasma brain-derived neurotrophic factor levels in patients with alcohol dependence, Alcohol. Clin. Exp. Res. 31 (2007) 1833–1838. [18] S.W. Johnson, R.A. North, Opioids excite dopamine neurons by hyperpolarization of local interneurons, J. Neurosci.: Off. J. Soc. Neurosci. 12 (1992) 483–488. [19] D.J. Kim, S. Roh, Y. Kim, S.J. Yoon, H.K. Lee, C.S. Han, Y.K. Kim, High concentrations of plasma brain-derived neurotrophic factor in methamphetamine users, Neurosci. Lett. 388 (2005) 112–115. [20] B.H. Lee, Y.K. Kim, Reduced platelet BDNF level in patients with major depression, Prog. Neuro-psychopharmacol. Biol. Psychiatry 33 (2009) 849–853. [21] Y. Lu, K. Christian, B. Lu, BDNF: a key regulator for protein synthesis-dependent LTP and long-term memory? Neurobiol. Learn. Mem. 89 (2008) 312–323. [22] M. Mitoma, R. Yoshimura, A. Sugita, W. Umene, H. Hori, H. Nakano, N. Ueda, J. Nakamura, Stress at work alters serum brain-derived neurotrophic factor (BDNF) levels and plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) levels in
J. Zhang et al. / Neuroscience Letters 571 (2014) 61–65
[23]
[24] [25]
[26]
healthy volunteers: BDNF and MHPG as possible biological markers of mental stress? Prog. Neuro-psychopharmacol. Biol. Psychiatry 32 (2008) 679–685. M.L. Molendijk, B.A. Bus, P. Spinhoven, B.W. Penninx, G. Kenis, J. Prickaerts, R.C. Voshaar, B.M. Elzinga, Serum levels of brain-derived neurotrophic factor in major depressive disorder: state-trait issues, clinical features and pharmacological treatment, Mol. Psychiatry 16 (2011) 1088–1095. E.J. Nestler, G.K. Aghajanian, Molecular and cellular basis of addiction, Science (New York, NY) 278 (1997) 58–63. A. Osman, J. Hoffman, F.X. Barrios, B.A. Kopper, J.L. Breitenstein, S.K. Hahn, Factor structure, reliability, and validity of the Beck anxiety inventory in adolescent psychiatric inpatients, J. Clin. Psychol. 58 (2002) 443–456. A.G. Pearse, The common peptides and the cytochemistry of their cells of origin, Basic Appl. Histochem. 24 (1980) 63–73.
65
[27] L. Sklair-Tavron, W.X. Shi, S.B. Lane, H.W. Harris, B.S. Bunney, E.J. Nestler, Chronic morphine induces visible changes in the morphology of mesolimbic dopamine neurons, Proc. Natl. Acad. Sci. U.S.A. 93 (1996) 11202–11207. [28] R. Spanagel, F. Weiss, The dopamine hypothesis of reward: past and current status, Trends Neurosci. 22 (1999) 521–527. [29] H. Thoenen, Neurotrophins and neuronal plasticity, Science (New York, NY) 270 (1995) 593–598. [30] H. Vargas-Perez, A.K.R. Ting, C.H. Walton, D.M. Hansen, R. Razavi, L. Clarke, M.R. Bufalino, D.W. Allison, S.C. Steffensen, D. van der Kooy, Ventral tegmental area BDNF induces an opiate-dependent-like reward state in naive rats, Science (New York, NY) 324 (2009) 1732–1734. [31] H. Yamamoto, M.E. Gurney, Human platelets contain brain-derived neurotrophic factor, J. Neurosci.: Off. J. Soc. Neurosci. 10 (1990) 3469–3478.
