miRNAs and Substances Abuse: Clinical and Forensic Pathological Implications: A Systematic Review

Substance addiction is a chronic and relapsing brain disorder characterized by compulsive seeking and continued substance use, despite adverse consequences. The high prevalence and social burden of addiction are indisputable; however, the available intervention is insufficient. The modulation of gene expression and aberrant adaptation of neural networks are attributed to the changes in brain functions under repeated exposure to addictive substances. Considerable studies have demonstrated that miRNAs are strong modulators of post-transcriptional gene expression in substance addiction. The emerging role of microRNA (miRNA) provides new insights into many biological and pathological processes in the central nervous system: their variable expression in different regions of the brain and tissues may play a key role in regulating the pathophysiological events of addiction. This work provides an overview of the current literature on miRNAs involved in addiction, evaluating their impaired expression and regulatory role in neuroadaptation and synaptic plasticity. Clinical implications of such modulatory capacities will be estimated. Specifically, it will evaluate the potential diagnostic role of miRNAs in the various stages of drug and substance addiction. Future perspectives about miRNAs as potential novel therapeutic targets for substance addiction and abuse will also be provided.

The Neurobiology of Methamphetamine Addiction and the Potential to Reduce Misuse Through Conjugate Vaccines Targeting Toll-Like Receptor 4

The methamphetamine epidemic continues to worsen each year and has contributed to more overdose deaths than opioids. Methamphetamine was listed in the top ten lethal drugs in 2021 in the United States. The drug has been shown to cause health problems such as addiction and neurological and behavioral changes. One possible solution to address this crisis is through vaccinations. Vaccinations consist of injecting a controlled substance with the goal of creating compound-specific antibodies. Although still early in development, vaccinations have been found to improve withdrawal symptoms and decrease drug-seeking behavior with minimal health side effects in rodent studies. This paper provides an overview of the clinical presentation and neurobiology of methamphetamine addiction and drug-seeking behaviors. The responses and adverse effects of conjugate vaccines IXTv-100 with adjuvant glucopyranosyl lipid A administered in oil-water stable emulsion and tetanus-toxoid conjugated to succinyl-methamphetamine adsorbed on aluminum hydroxide combined with adjuvant E6020 are examined.

Serum brain-derived neurotrophic factor levels in patients with schizophrenia and methamphetamine addiction: correlation with Mini-Mental State Examination (MMSE)

Methamphetamine use can induce psychosis resembling acute schizophrenia spectrum psychosis, making it challenging to differentiate between the two based on symptoms alone. Brain-derived neurotrophic factor (BDNF) exerts a critical role in hippocampal neural plasticity, influencing critical cognitive functions such as memory and learning. This study aimed to determine the role of serum BDNF levels in schizophrenia and methamphetamine addiction. A case-control study was conducted involving 50 patients with schizophrenia, 50 patients with methamphetamine addiction, and 50 healthy control subjects recruited from Ibn-Rushed Psychiatric Teaching Hospital in Baghdad. Cognitive impairment was assessed using the Mini-Mental State Examination (MMSE), while serum BDNF levels were measured using ELISA following standardized protocols. The findings revealed significantly lower median levels of BDNF (0.36 pg/ml) in patients with schizophrenia compared to both the control group (0.51 pg/ml) and the methamphetamine group (0.72 pg/ml). Moreover, there was a significant difference observed between the methamphetamine group and the control group. At a cut-off value of BDNF=0.37 pg/ml, the sensitivity and specificity of BDNF in differentiating between schizophrenia and methamphetamine addiction were 84% and 70%, respectively. Serum level of BDNF could be used to differentiate between schizophrenia and methamphetamine addiction when clinical distinctions are challenging to detect.

Challenges and future trends in wearable closed-loop neuromodulation to efficiently treat methamphetamine addiction

Achieving abstinence from drugs is a long journey and can be particularly challenging in the case of methamphetamine, which has a higher relapse rate than other drugs. Therefore, real-time monitoring of patients' physiological conditions before and when cravings arise to reduce the chance of relapse might help to improve clinical outcomes. Conventional treatments, such as behavior therapy and peer support, often cannot provide timely intervention, reducing the efficiency of these therapies. To more effectively treat methamphetamine addiction in real-time, we propose an intelligent closed-loop transcranial magnetic stimulation (TMS) neuromodulation system based on multimodal electroencephalogram-functional near-infrared spectroscopy (EEG-fNIRS) measurements. This review summarizes the essential modules required for a wearable system to treat addiction efficiently. First, the advantages of neuroimaging over conventional techniques such as analysis of sweat, saliva, or urine for addiction detection are discussed. The knowledge to implement wearable, compact, and user-friendly closed-loop systems with EEG and fNIRS are reviewed. The features of EEG and fNIRS signals in patients with methamphetamine use disorder are summarized. EEG biomarkers are categorized into frequency and time domain and topography-related parameters, whereas for fNIRS, hemoglobin concentration variation and functional connectivity of cortices are described. Following this, the applications of two commonly used neuromodulation technologies, transcranial direct current stimulation and TMS, in patients with methamphetamine use disorder are introduced. The challenges of implementing intelligent closed-loop TMS modulation based on multimodal EEG-fNIRS are summarized, followed by a discussion of potential research directions and the promising future of this approach, including potential applications to other substance use disorders.

A Single Nucleotide Polymorphism Within Molybdenum Cofactor Sulfurase Gene Is Associated With Neuropsychiatric Conditions

Background

Molybdenum cofactor sulfurase (MOCOS) is an enzyme participating in purine metabolism. The aim of current study was to evaluate the role of a single nucleotide polymorphism (SNP) in the coding gene (rs594445) in mood disorders and methamphetamine addiction.

Methods

This SNP was genotyped in 200 persons with methamphetamine addiction, 85 patients with bipolar disorder 1 (BP1), 78 patients with BP2, 33 patients with major depressive disorder (MDD) and 200 age-/sex-matched normal subjects using the tetra-primer amplification-refractory mutation system (ARMS)-PCR technique.

Results

The rs594445 was associated with methamphetamine addiction in co-dominant model [A/A vs C/C: OR (95% CI) = 0.466 (0.252–0.864), P-value = 0.014; C/A vs C/C: OR (95% CI) = 0.641 (0.418–0.981), P-value = 0.04]. This SNP was also associated with this trait in dominant model [OR (95% CI) = 0.591 (0.398–0.879), P-value = 0.009]. The A allele of rs594445 had a protective role against methamphetamine addiction [A vs C: OR (95% CI) = 0.645 (0.48–0.866), P-value = 0.004]. The rs594445 was associated with BP1 in co-dominant model [C/A vs C/C: OR (95% CI) = 0.423 (0.230–0.778), P-value = 0.005]. However, the associations were insignificant in other inheritance models.

Conclusion

Finally, there were no significant associations between the mentioned SNP and risk of BP2 or MDD in any inheritance model. The present project highlights the role rs594445 in two psychiatric conditions and implies the presence of common genetic factors for these disorders.

Effects of Exercise on Depression, Anxiety, Cognitive Control, Craving, Physical Fitness and Quality of Life in Methamphetamine-Dependent Patients

Methamphetamine (MA) abuse results in a variety of harmful changes in mood states and cognitive function, together with declined physical health and quality of life. Recent studies highlighted the therapeutic potential of physical exercise on MA addiction. Physical exercise improves emotional state and general health conditions, enhances cognitive function, reduces relapse rate, and facilitates abstinence, thereby improves the overall quality of life of the drug users. This review summarizes the present situation of physical exercise on MA-dependent patients with both animal and clinical population results.

The neurobiological mechanisms of physical exercise in methamphetamine addiction

Methamphetamine (METH) is the primary drug within amphetamine-type stimulants which are the second most abused group of drugs worldwide. There is no pharmacological treatment addressed specifically to METH addiction, and behavioral therapy is shadowed by poor long-term recovery and relapse. Therefore, novel approaches to manage METH addiction are an urgent need. This review aims to describe the current state of physical exercise use on methamphetamine addiction management. The following searching terms in PubMed were used: ("physical exercise" OR "exercise") AND "methamphetamine." Relevant references from key publications and gray literature were also reviewed to identify additional citations for inclusion. Original investigation regarding physical exercise and methamphetamine addiction (clinical data) or neurobiological mechanisms of physical exercise in animal models of methamphetamine administration (preclinical data) was included. Overall, METH users demonstrated improvements, including better fitness and emotional measures, lower relapse rates, and sustained abstinence when compared to nonexercised individuals. The neurobiological mechanisms of physical exercise in METH users seem to reflect an interplay of several agents, including neurochemicals, oxidative stress, neurogenesis, gliogenesis, and blood-brain barrier as disclosed by preclinical data. Exercise-based interventions alone or as a conjoint therapy may be a useful tool for managing METH addiction.