Orexin A in men with heroin use disorder undergoing methadone maintenance treatment

Differences in orexin-A level in the functional brain network of HUD patients undergoing harm reduction therapy

Orexins regulate the reward-seeking pathway and also play a role in drug addiction. The aim of this study was an investigation of the changes in serum level of orexin-A as well as changes in the functional brain network in heroin use disorder (HUD) patients undergoing harm reduction therapy (HRT). Twenty-five HUD patients undergoing HRT that included methadone and buprenorphine, and 31 healthy control (HC) subjects, were enrolled for this study. Serum orexin-A levels and brain-derived neurotrophic factor were measured with assay kits. The functional brain network in HUD patients and HC was investigated and assessed using seed-based analysis and functional brain MRI scans. t Tested orexin-A levels were found to be significantly higher in HUD patients undergoing HRT than in HCs (P < .05). Analysis showed the functional activity of the right ventral anterior insula (RVAI) in HUD patients to be significantly lower than in HCs (P < .05, Family-Wise Error) corrected). In addition, the internetwork functional connectivity was significantly lower in the left nucleus accumbens and left dorsal anterior insula in the HUD subjects than in HCs (P < .05, Family-Wise Error corrected). In this study, no significant correlation between orexin-A levels and functional brain networks was found. However, the results suggest that HRT might increase orexin-A levels and decrease functional activity in RVAI in HUD patients.

Alteration of orexin-A and PKCα in the postmortem brain of pure-opioid and multi-drug abusers

Finding changes induced by the drug of abuse is one of the most important approaches to design new drugs for the treatment of substance use disorders (SUD). Postmortem study is the most reliable method for detecting alteration in the brain of SUD patients. Recently, the role of orexinergic system in SUD is in consideration. In the current study, we evaluated the level of orexin-A in the CSF and protein kinase Cα (PKCα) in the brain of pure-opioid (POA) and multi-drug abusers (MDA). A total of 56 POA, 45 MDA, and 13 matched control brains were collected from the legal medicine center, Tehran, Iran. The CSF was gathered from the third ventricle immediately after opening the skull and kept at -80 °C. The medial prefrontal cortex (mPFC), lateral prefrontal cortex (lPFC), orbitofrontal cortex (OFC), nucleus accumbens (NAc), and amygdala were dissected from fresh brain, frozen with liquid nitrogen and kept at -80 °C. The level of orexin-A evaluated in the CSF. Using western blotting, the level of PKCα assessed in the brain. Obtained data revealed that the level of orexin-A increased in POA and MDA compared with the control group (p < 0.05). In addition, the level of PKCα increased in the prefrontal cortex and amygdala of the abusers compared with the control group, although we did not detect changes in the level of PKCα in the NAc. Along with animal studies, the current results showed that the level of orexin increased in the CSF of drug abusers, which might be related to increases in the activation of lateral hypothalamic orexinergic neurons faced with the drug of abuse. Enhancement in the level of PKCα in the drug reward circuits might be adaptational changes induced by orexin and drugs of abuse.

Evaluation of the relationship between the gene expression level of orexin-1 receptor in the rat blood and prefrontal cortex, novelty-seeking, and proneness to methamphetamine dependence: A candidate biomarker

BACKGROUND

previous studies have suggested that methamphetamine (METH) abuse may affect orexin regulation. However, the data regarding the relationship between the current level of orexin and the vulnerability to METH abuse are minimal. Here, we have investigated the correlation between the gene expression level of the orexin-1 receptor (OX1R) in the rat prefrontal cortex (PFC) and blood lymphocytes and susceptibility to METH dependence and its impact on novelty-seeking behavior.

METHODS

male Wistar rats were first examined for novelty-seeking behavior by the novel object recognition test, and the expression level of OX1R in their blood lymphocytes was evaluated by real-time PCR. Then, the susceptibility to METH abuse was investigated by voluntary METH oral consumption test. According to the amounts of METH consumption, the animals were divided into two groups of METH preferring and non-preferring. Half of the rats in each group were sacrificed, and the level of OX1R in their blood lymphocytes and PFC tissue was measured. The other half were sacrificed for the same reason after two weeks of drug abstinence.

RESULTS

The indexes of novelty-seeking behavior were significantly higher in the METH- preferring group compared to the non-preferring animals. Furthermore, the expression level of OX1R in the blood lymphocytes and PFC in the preferring group was considerably higher than the non-preferring group.

CONCLUSION

Up-regulation of the mRNA expression level of OX1R in the lymphocytes and PFC may predict vulnerability to the METH consumption and novelty-seeking, which may serve as a potential biomarker for METH abuse.

Involvement of orexinergic system in psychiatric and neurodegenerative disorders: A scoping review

Orexin is a neuropeptide secreted from lateral hypothalamus and pre-frontal cortex concerned in the wakefulness and excitement. This study aimed to review the possible neurobiological effect of orexin. A diversity of search strategies was adopted and assumed which included electronic database searches of Medline and PubMed using MeSH terms, keywords, and title words during the search. Orexin plays a vital role in activation of learning, memory acquisition, and consolidation through activation of monoaminergic system, which affect cognitive flexibility and cognitive function. Orexin stimulates adrenocorticotropin and corticosteroid secretions via activation of central corticotropin-releasing hormone. Cerebrospinal fluid (CSF) and serum orexin serum levels are reduced in depression, schizophrenia, and narcolepsy. However, high orexin serum levels are revealed in drug addictions. Regarding neurodegenerative brain diseases, CSF and serum orexin serum levels are reduced Parkinson disease, Alzheimer dementia, Huntington's disease, amyotrphic lateral sclerosis, and multiple sclerosis. Orexin antagonist leads to significant reduction of sympathetic over-activity during withdrawal syndrome. As well, orexin antagonist improves sleep pattern. Orexinergic system is involved in the different psychiatric and neurological disorders; therefore, targeting of this system could be possible novel pathway in the management of these disorders. In addition, measurement of CSF and serum orexin levels might predict the relapse and withdrawal of addict patients.

Differences in Gut Microbial Diversity are Driven by Drug Use and Drug Cessation by Either Compulsory Detention or Methadone Maintenance Treatment

In this work, we investigate differences in gut microbial diversity driven by drug use or by the widely used methods for drug cessation: methadone maintenance treatment (MMT) and compulsory detention (CD). Methods: 99 participants (28 CD participants, 16 MMT patients, 27 drug users, and 28 healthy controls) were selected using strict inclusion criteria. Nutritional intake and gut microbial diversity were analyzed with bioinformatics tools and SPSS 20.0. Results: Alpha diversity was not significantly different among groups, whereas beta diversity of gut microbiota and nutrient intake were significantly higher among MMT patients. Taxa were unevenly distributed between groups, with drug users having the highest proportion of Ruminococcus and MMT patients having the highest abundance of Bifidobacterium and Lactobacillus. Conclusion: Drug use, cessation method, and diet contribute to shaping human gut communities. High beta diversity among MMT patients is likely driven by methadone use and high nutrient intake, leading to increased orexin A and enrichment for beneficial bacteria, while diversity in CD participants is largely influenced by diet.

Prognostic roles of sleep electroencephalography pattern and circadian rhythm biomarkers in the recovery of consciousness in patients with coma: a prospective cohort study

OBJECTIVE

To investigate the potential prognostic value of sleep electroencephalography (EEG) pattern and serum circadian rhythm biomarkers in the recovery of consciousness in patients at the acute stage of coma.

METHODS

A prospective observational study which included 75 patients with coma was conducted. Twenty-four-hour continuous polysomnography (PSG) was performed to determine the sleep EEG pattern according to the modified Valente's Grade (mVG) that we proposed. Serum levels of melatonin and orexin-A at four consecutive time points during the PSG were examined. Patients were then followed for one month to determine their level of consciousness. Multivariate logistic regression analysis was performed to examine associations between demographics, aetiology, baseline clinical features (pupillary and corneal reflex, and neuron-specific enolase [NSE]), clinical scores (Glasgow Coma Scale-Motor Response [GCS-M], Full Outline of Unresponsiveness [FOUR] scale, Acute Physiology and Chronic Health Evaluation II [APACHE II] scale), mVG, serum circadian biomarkers, and recovery of consciousness within one month.

RESULTS

Within one month of enrolment, 34 patients regained consciousness and 36 patients remained non-conscious. Spearman rank correlation revealed a significant association between mVG and state of consciousness after one month. Significant variation in serum melatonin or orexin-A was not detected in either the conscious or non-conscious groups. Hypoxic aetiology, APACHE II, and mVG were independently associated with recovery of consciousness within one month.

CONCLUSION

Sleep EEG structure, hypoxic aetiology, and APACHE II can independently predict recovery of consciousness in patients with acute coma. Taken together, we encourage neurologists to use sleep elements to assess patients with acute coma.