Methamphetamine Induces Systemic Inflammation and Anxiety: The Role of the Gut–Immune–Brain Axis

Valerenic acid ameliorates amphetamine-related neurotoxicity by improving hypothalamus tyrosine hydroxylase and histamine-N-methyl transferase enzymes

Background

Narcolepsy, obesity, and attention deficit hyperactivity disorder are all treated with amphetamine (a central nervous system stimulant) while valerenic acid (VA) has a pharmacological effect in the central nervous system.

Objectives

The purpose of this study was to ascertain whether VA is able to make amends for neurotoxicity by modifying hypothalamus expressions of the enzymes tyrosine hydroxylase and histamine-N-methyl transferase in rats orally administered with methamphetamine (METH).

Methods

There were thirty-six male albino rats split up into six equal groups, Control, VA (5 mg/kg)-treated, and VA (10 mg/kg)-treated groups: For four weeks, normal rats received oral administration of 1 ml of distilled water, 5 mg/kg of VA, and 10 ml/kg of VA once daily. METH-treated, VA (5 mg/kg) prior to METH-treated, and VA (10 mg/kg) before METH-treated groups: normal rats were oral administrated with METH (2.5 mg/kg), 3 days/week for 3 weeks, where the last two groups were oral administrated daily during four weeks at 5 mg/kg and 10 mg/kg VA, starting one week prior to METH administration.

Results

METH decreased superoxide dismutase, glutathione peroxidase, catalase, NADPH oxidase, interleukin-10, sucrose preference test, distance traveled test, and center square entries test, ATPase activity and the enzymes tyrosine hydroxylase and histamine-N-methyl transferase but increased malondialdehyde, conjugated dienes, oxidative index, serotonin, dopamine, norepinephrine, γ-aminobutyric acid, tumor necrosis factor-α, interleukin-1β, interleukin-6, nuclear factor kappa B levels, the center square duration test, tail suspension test, and forced swimming test. in the METH-treated animals' brain in contrast to the control group. After four weeks of oral administration of VA to METH-treated rats, all of these parameters returned to levels that were nearly control, indicating that a higher dose was more effective than a lower one.

Conclusion

VA ameliorated METH-related neurotoxicity by improving hypothamalus expressions of the enzymes tyrosine hydroxylase and histamine-N-methyl transferase.

Intestinal barrier damage caused by addictive substance use disorder

Addictive substance use disorder has a wide range of effects on the intestinal barrier, including damage to the biological, chemical, mechanical, and immune barriers. Damage to the intestinal barrier caused by addictive substance use disorder allows harmful substances and bacteria to cross the intestinal barrier into the circulatory system, leading to systemic inflammatory responses and immune imbalances. In addition, the interaction between the gut flora and the central nervous system is recognized as an important component of the gut-brain axis. Gut barrier damage leads to dysbiosis, which in turn affects brain function by activating immune cells and releasing inflammatory factors. This may lead to altered mood and cognitive function, increased addictive substance cravings, and dependence. Recent research has indicated that reshaping the gut-brain axis and adjusting the composition and abundance of gut microbiota holds promise in alleviating withdrawal symptoms with addictive substance dependence. This article reviews the effects of addictive substance use disorder on the intestinal barrier and explores the possibility of improving addictive substance dependence by treating gut barrier damage.

Case Report: Unusual oral cavity changes associated with methamphetamine abuse

Methamphetamine abuse is a growing global health concern, recognized for its highly addictive properties and severe effects on the human body. Commonly referred to as crystal, chalk, or ice, methamphetamine is a synthetic stimulant that can be administered in various ways. Methamphetamine abuse is associated with a spectrum of oral health issues known as "meth mouth," including rampant teeth caries, extensive occlusal tooth wear, periodontal diseases, xerostomia, bruxism, and poor oral hygiene. Despite the significant oral health impact, the exact pathogenesis remains unclear due to the limited number of reported cases and comprehensive studies performed. This case series details changes in oral and general health of different severity associated with methamphetamine abuse, highlighting unusual presentations such as the generalized decrease in teeth sensitivity, which can be associated with aseptic tooth pulp necrosis, hairy black tongue, rampant arrested caries, decreased periodontal inflammation, specific sunflower seed abrasions on antagonistic central incisors, pityriasis rosea skin lesion and palmar erythema. The clinical management was presented in detail and justified, which entails conservative dental, periodontal and oral mucosae treatments and highlighted the need for a comprehensive complex examination of these patients and financial consideration in treatment planning. This case series underscores the need to recognize the diverse oral and general health effects of methamphetamine abuse, which vary with duration and individual symptoms. Patients often withhold substance use, leading to delayed diagnosis until severe manifestations arise. Enhanced awareness among healthcare providers can improve diagnosis and management, offering valuable insights into underlying mechanisms and enabling better care for this high-risk population.

The interaction between central and peripheral immune systems in methamphetamine use disorder: current status and future directions

Methamphetamine (METH) use disorder (MUD) is characterized by compulsive drug-seeking behavior and substantial neurotoxicity, posing a considerable burden on individuals and society. Traditionally perceived as a localized central nervous system disorder, recent preclinical and clinical studies have elucidated that MUD is a multifaceted disorder influenced by various biological systems, particularly the immune system. Emerging evidence suggests that both central and peripheral immune responses play a crucial role in the initiation and persistence of MUD. Conceptualizing it as a systemic immune process prompts significant inquiries regarding the mechanisms of communication between peripheral and central compartments. Also, whether this intercommunication could serve as diagnostic biomarkers or therapeutic targets. This review begins by offering an overview of mechanistic studies pertaining to the neuroimmune and peripheral immune systems. Finally, future directions are suggested through the integration of innovative technologies and multidimensional data to promote the translation of basic mechanistic research into clinical diagnostic and therapeutic interventions.

Syndromic and Non-Syndromic Primary Failure of Tooth Eruption: A Genetic Overview

Primary failure of tooth eruption (PFE) is a rare genetic disorder characterized by the failure of teeth to erupt in the absence of obvious physical obstructions, often resulting in a progressive open bite that is resistant to orthodontic treatment. While PFE can be caused by genetic or systemic factors (such as cysts, tumors, and endocrine imbalances), the non-syndromic causes are primarily genetic, with an autosomal dominant inheritance pattern with variable expressivity. Several genes have been closely associated with the non-syndromic PFE form. The PTH1R (parathyroid hormone 1 receptor) is the most commonly PFE-associated gene. Additional genes associated with minor frequency are Transmembrane protein 119 (TMEM119), which reduces the glycolytic efficiency of bone cells, limiting their mineralization capacity and causing bone fragility; Periostin (POSTN), which regulates the extracellular matrix and the bone's response to mechanical stress; and Lysine (K)-specific methyltransferase 2C (KMT2C), which establishes histone methylation near the Wnt Family Member 5A (WNT5A) gene involved in dental development (odontogenesis). Syndromic forms of PFE are typically associated with complex multisystem disorders, where dental eruption failure is one of the clinical features of the spectrum. These syndromes are often linked to genetic variants that affect ectodermal development, craniofacial patterning, and skeletal growth, leading to abnormal tooth development and eruption patterns. Notable syndromes include GAPO syndrome, ectodermal dysplasia, and cleidocranial dysplasia, each contributing to PFE through distinct molecular mechanisms, such as disruptions in dental structure development, cranial abnormalities, or systemic developmental delays. The main aim of this review is to provide a comprehensive overview of the genetic basis underlying both syndromic and non-syndromic forms of PFE to facilitate precision diagnosis, foster the development of personalized therapeutic strategies, and offer new insights into managing this complex dental anomaly.

The effect of paeoniflorin on the rewarding effect of methamphetamine and the associated cognitive impairment in mice

Chronic exposure to methamphetamine (METH) has been suggested to cause METH use disorder and severe cognitive impairment. Paeoniflorin (PF) is a monoterpenoid glycoside with various beneficial effects, including anti-inflammatory, antioxidant and antidepressant. The current study was designed to investigate the effect of PF (30 mg/kg, i.p.) on the rewarding effect of METH (2.5 mg/kg, i.p.) and the associated cognitive impairment, using the animal model of conditioned place preference, new location reorganization test, new object reorganization test and Y-maze test. METH induced conditioned place preference, accompanied by increased expression of synapse-associated proteins in the ventral target areas (VTA) and nucleus accumbens (NAc). In addition, METH induced significant cognitive impairment and decreased the expression of synapse-associated proteins in the hippocampus (Hip). Administration of PF decreased the rewarding effect of METH and the expression of synapse-associated proteins in the VTA or NAc. PF was also effective to improve METH-induced cognitive impairment by upregulating the expression of synapse-associated proteins in the Hip. Therefore, PF could be a potential agent for the treatment of METH use disorder and the associated cognitive impairment.

A methamphetamine vaccine using short monoamine and diamine peptide linkers and poly-mannose

Methamphetamine (METH) substance use disorder is a long-standing and ever-growing public health concern. Efforts to develop successful immunotherapies are ongoing with vaccines that generate strong antibody responses are an area of significant research interest. Herein, we describe the development of a METH Hapten conjugate vaccine comprised of either two short-length peptides as linkers and mannan as an immunogenic delivery carrier. Initially, Hapten 1 (with a monoamine linker) and Hapten 2 (with a diamine linker) were synthesised. Each step of the Hapten synthesis were characterized by LC-MS and purified by Flash Chromatography and the identity of the purified Haptens were confirmed by 1H NMR. Haptens were conjugated with mannan (a polymannose), and conjugation efficiency was confirmed by LC-MS, TLC, 1H NMR, and 2,4 DNPH tests. The immunogenic potential of the two conjugated vaccines were assessed in mice with a 3-dose regimen. Concentrations of anti-METH antibodies were measured by enzyme-linked immunosorbent assay. All the analytical techniques confirmed the identity of Hapten 1 and 2 during the synthetic phase. Similarly, all the analytical approaches confirmed the conjugation between the Haptens and mannan. Mouse immunogenicity studies confirmed that both vaccine candidates were immunogenic and the vaccine with the monoamine linker plus adjuvants induced the highest antibody response after the second booster.

Inhibition of GSDMD-dependent pyroptosis decreased methamphetamine self-administration in rats

It is widely believed that the activation of the central dopamine (DA) system is crucial to the rewarding effects of methamphetamine (METH) and to the behavioral outcomes of METH use disorder. It was reported that METH exposure induced gasdermin D (GSDMD)-dependent pyroptosis in rats. The membrane pore formation caused by METH-induced pyroptosis may also contribute to the overflow of DA into the extracellular space and subsequently increase the DA levels in the brain. The present study firstly investigated whether the membrane pore information induced by GSDMD-dependent pyroptosis was associated with the increased DA levels in the ventral tegmental area (VAT) and nucleus accumbens (NAc) of rats self-administering METH and SY-SH5Y cells treated by METH. Subsequently, the effect of pore formation blockade or genetic inhibition of GSDMD on the reinforcing and motivational effect of METH was determined in rats, using the animal model of METH self-administration (SA). METH exposure significantly increased the activity of NLRP1/Cas-1/GSDMD pathway and the presence of pyroptosis, accompanied by the significantly increased DA levels in VTA and NAc. Moreover, intraperitoneal injections of disulfiram (DSF) or microinjection of rAAV-shGSDMD into VTA/NAc significantly reduced the reinforcing and motivational effect of METH, accompanied by the decreased level of DA in VTA and NAc. The results provided novel evidence that METH-induced pyroptosis could increase DA release in VTA and NAc via the NLRP1/Cas-1/GSDMD pathway. Additionally, membrane pores or GSDMD blockade could significantly reduce the reinforcing and motivational effect of METH. In conclusion, blocking GSDMD and membrane pore formation could be a promising potential target for the development of agents to treat METH use disorder.

Efficacy of probiotic supplements in improving the symptoms of psychosis, anxiety, insomnia, and anorexia due to amphetamine and methamphetamine use: a randomized clinical trial

RATIONALE

Changes in the density and diversity of gut microbiota in chronic use of methamphetamine have been mentioned as contributors to psychotic and anxiety symptoms, sleep problems, and loss of appetite.

OBJECTIVE

In this placebo-controlled clinical trial, we investigated the effect of the probiotic Lactobacillus Acidophilus in improving psychiatric symptoms among hospitalized patients with chronic methamphetamine use along with psychotic symptoms.

METHODS

60 inpatients with a history of more than 3 years of methamphetamine use, were randomly assigned to one of two groups receiving either a probiotic capsule or placebo along with risperidone for 8 weeks based on a simple randomization method. In weeks 0, 4, and 8, patients were evaluated using the Brief Psychiatric Rating Scale (BPRS), Beck Anxiety Inventory (BAI), Pittsburgh Sleep Quality Index (PSQI), Simple Appetite Nutritional Questionnaire (SANQ), and Body Mass Index (BMI).

RESULTS

Compared to the control group, patients receiving probiotics had better sleep quality, greater appetite, and higher body mass index (there were significant interaction effects of group and time at Week 8 in these variables (t = -3.32, B = -1.83, p = .001, d = 0.89), (t = 10.50, B = 2.65, p <.001, d = 1.25) and (t = 3.40, B = 0.76, p <.001, d = 0.30), respectively. In terms of the improvement of psychotic and anxiety symptoms, there was no statistically significant difference between the two groups.

CONCLUSIONS

The use of probiotics was associated with improved sleep quality, increased appetite, and increased body mass index in patients with chronic methamphetamine use. Conducting more definitive clinical trials with larger sample sizes and longer-term follow-up of cases is recommended.

Evaluation of Complete Blood Cell Count Parameters and Their Role in Inflammation in Patients with Methamphetamine and Synthetic Cannabis Use Disorder

Background

The aim of this study was to compare the complete blood cell count parameters of patients with methamphetamine and synthetic cannabis use disorder (MCUD), a condition that has recently exhibited a gradual increase in prevalence, with those of healthy subjects.

Methods

In total, 76 patients diagnosed with MCUD and 78 healthy controls were included in the study. Venous blood samples were collected from all participants at presentation for laboratory examination.

Results

The rate of mono- and poly-substance users in the patient group was 14.5% and 85.5%, respectively. The average duration of methamphetamine (METH) use in the patient group is 3.0 ± 1.9 years. White blood cell (P < .001), PLT (P = .005), monocyte count (P < .001), basophil count (P < .001), neutrophil count (P < .001), lymphocyte count (P < .001) basophil/lymphocyte ratio (BLR) (P = .04), SII (P = .006), and SIRI (P = .001) values were significantly higher. In contrast Hgb (P = .043), Hct (P = .002), monocyte percentage (P = .004), and RBC (P = .021) values were significantly lower in the MCUD group compared to the control group. There was a significant positive correlation between neutrophil/lymphocyte ratio and platelet/lymphocyte ratio (r = .552 P < .001) and between systemic immune inflammatory index (SII) and systemic inflammation response index (SIRI) (r = 0.580 P < .001).

Conclusion

Methamphetamine and cannabis may affect the levels of inflammatory markers and SII and SIRI values through various mechanisms. To the best of our knowledge, this is the first study in the relevant literature, which investigated SII and SIRI values in patients with MCUD, therefore, the results can contribute to the future development of immune system-related markers in this field.

TMEM119 (c.G143A, p.S48L) Mutation Is Involved in Primary Failure of Eruption by Attenuating Glycolysis-Mediated Osteogenesis

Primary failure of eruption (PFE) is a rare oral disease with an incidence rate of 0.06%. It is characterized by abnormal eruption mechanisms that disrupt tooth eruption. The underlying pathogenic genetic variant and mechanism of PFE remain largely unknown. The purpose of this study was to explore the role of a novel transmembrane protein 119 (TMEM119) mutation in two PFE patients in a Chinese family. Information collection was performed on the family with a diagnosis of PFE, and blood samples from patients and healthy family members were extracted. Whole-exome sequencing was performed. Bioinformatics analysis revealed that a heterozygous variant in the TMEM119 gene (c.G143A, p.S48L) was a disease-associated mutation in this family. Recombinant pcDNA3.1 plasmid-containing wild-type and mutant TMEM119 expression cassettes were successfully constructed and transfected into MC3T3-E1 cells, respectively. The results of in vitro analysis suggested that the subcellular distribution of the TMEM119 protein was transferred from the cell cytoplasm to the nucleus, and the ability of cells to proliferate and migrate as well as glycolytic and mineralized capacities were reduced after mutation. Furthermore, rescue assays showed that activating transcription factor 4 (ATF4) overexpression rescued the attenuated glycolysis and mineralization ability of cells. Results of in vivo analysis demonstrated that TMEM119 was mainly expressed in the alveolar bone around the mouse molar germs, and the expression level increased with tooth eruption, demonstrated using immunohistochemistry and immunofluorescence. Collectively, the novel TMEM119 mutation is potentially pathogenic in the PFE family by affecting the glucose metabolism and mineralized function of osteoblasts, including interaction with ATF4. Our findings broaden the gene mutation spectrum of PFE and further elucidate the pathogenic mechanism of PFE.

Luteolin amends neural neurotransmitters, antioxidants, and inflammatory markers in the cerebral cortex of Adderall exposed rats

BACKGROUND

Adderall is a central nervous system stimulant while luteolin has neuroprotective activity. This study aimed to determine whether luteolin can amend neural neurotransmitters, antioxidants, and inflammatory markers in the cerebral cortex of Adderall exposed rats.

METHODS

Thirty-six male albino rats were divided into 6 equal groups, Control, Luteolin (1 g/kg)-treated, and Luteolin (2 g/kg)-treated groups: normal rats were orally administrated once a day with 2 ml distilled water, luteolin (1 g/kg), and luteolin (2 g/kg), respectively for 4 weeks. Adderall rats, Adderall rats + luteolin (1 g/kg)-treated, and Adderall rats + luteolin (2 g/kg)-treated groups: normal rats were orally administrated once a day with 10 mg/kg of Adderall, 3 days/week for 4 weeks, then these rats orally administrated daily once a day with 2 ml of distilled water, luteolin (1 g/kg), and luteolin (2 g/kg), respectively for another 4 weeks.

RESULTS AND CONCLUSION

Adderall decreased superoxide dismutase, glutathione peroxidase, catalase, NADPH oxidase, interleukin-10, serotonin, dopamine, norepinephrine, γ-aminobutyric acid, and acetylcoline estrase but increased malondialdehyde, conjugated dienes, oxidative index, tumour necrosis factor-α, interleukin-1β, and interleukin-6 levels in the cerebral cortex. Adderall increased the expression of glial fibrillary acidic protein, ionized calcium binding adaptor molecule 1, and anti-calbindin in the cerebral cortex of Adderall-treated rats. In Adderall-treated rats, daily oral administration of luteolin for 4 weeks brought all these parameters back to values that were close to control where higher dose was more effective than lower dose. The importance of this research is to provide natural compound that amends Adderall-related neural disturbances and this natural compound is cheap, avaliable without any side effect and it does not interfer with Adderall efficiency.

Vaccines to Treat Substance Use Disorders: Current Status and Future Directions

Addiction, particularly in relation to psychostimulants and opioids, persists as a global health crisis with profound social and economic ramifications. Traditional interventions, including medications and behavioral therapies, often encounter limited success due to the chronic and relapsing nature of addictive disorders. Consequently, there is significant interest in the development of innovative therapeutics to counteract the effects of abused substances. In recent years, vaccines have emerged as a novel and promising strategy to tackle addiction. Anti-drug vaccines are designed to stimulate the immune system to produce antibodies that bind to addictive compounds, such as nicotine, cocaine, morphine, methamphetamine, and heroin. These antibodies effectively neutralize the target molecules, preventing them from reaching the brain and eliciting their rewarding effects. By obstructing the rewarding sensations associated with substance use, vaccines aim to reduce cravings and the motivation to engage in drug use. Although anti-drug vaccines hold significant potential, challenges remain in their development and implementation. The reversibility of vaccination and the potential for combining vaccines with other addiction treatments offer promise for improving addiction outcomes. This review provides an overview of anti-drug vaccines, their mechanisms of action, and their potential impact on treatment for substance use disorders. Furthermore, this review summarizes recent advancements in vaccine development for each specific drug, offering insights for the development of more effective and personalized treatments capable of addressing the distinct challenges posed by various abused substances.

The Common Denominators of Parkinson's Disease Pathogenesis and Methamphetamine Abuse

The pervasiveness and mortality associated with methamphetamine abuse have doubled during the past decade, suggesting a possible worldwide substance use crisis. Epitomizing the pathophysiology and toxicology of methamphetamine abuse proclaims severe signs and symptoms of neurotoxic and neurobehavioral manifestations in both humans and animals. Most importantly, chronic use of this drug enhances the probability of developing neurodegenerative diseases manifolds. Parkinson's disease is one such neurological disorder, which significantly and evidently not only shares a number of toxic pathogenic mechanisms induced by methamphetamine exposure but is also interlinked both structurally and genetically. Methamphetamine-induced neurodegeneration involves altered dopamine homeostasis that promotes the aggregation of α-synuclein protofibrils in the dopaminergic neurons and drives these neurons to make them more vulnerable to degeneration, as recognized in Parkinson's disease. Moreover, the pathologic mechanisms such as mitochondrial dysfunction, oxidative stress, neuroinflammation and decreased neurogenesis detected in methamphetamine abusers dramatically resemble to what is observed in Parkinson's disease cases. Therefore, the present review comprehensively cumulates a holistic illustration of various genetic and molecular mechanisms putting across the notion of how methamphetamine administration and intoxication might lead to Parkinson's disease-like pathology and Parkinsonism.

Linalool attenuates hypothalamus proteome disturbance facilitated by methamphetamine induced neurotoxicity in rats

BACKGROUND

One of the most powerful stimulants of the central nervous system is methamphetamine (METH). Linalool has a neuroprotective effect against ischemia injury by reducing oxidative stress and apoptosis. The present study investigated whether linalool can reverse the hypothalamus neurotoxicity and proteome disturbance in METH-treated rats.

BRIEF METHOD

A total of 36 male albino rats were split into two equal groups (normal and METH-treated). Three equal subgroups of normal rats were created; Control, Linalool (25 mg/kg), and Linalool (50 mg/kg); Normal rats were given daily oral doses of 1 ml of distilled water, 25 mg/kg linalool, and 50 mg/kg of linalool, respectively. METH groups were divided into 3 equal subgroups; METH-treated rats, Linalool (25 mg/kg)+METH-treated, and Linalool (50 mg/kg)+METH-treated subgroups; METH-treated rats received daily and oral doses of 1 ml distilled water, 25 mg/kg linalool, and 50 mg/kg of linalool, respectively.

RESULTS

According to the data obtained, METH caused a decrease of the sucrose preference test, travel distance test, and center square entries test, superoxide dismutase, glutathione peroxidase, catalase, NADPH oxidase, interleukin-10 but a rise in the center square duration test, tail suspension test, and forced swimming test, malondialdehyde, conjugated dienes, oxidative index, serotonin, dopamine, norepinephrine, γ-aminobutyric acid, tumour necrosis factor-α, interleukin-1β, interleukin-6 levels. When compared to the control group, rats treated with METH had lower sodium/potassium ATPase activity and missing of prothrombin, fibrinogen, and ceruloplasmin protein bands in the hypothalamus. In METH-treated rats, daily and oral co-administration with linalool brought all these parameters back to values that were close to control.

SIGNIFICANCE

According to obtained data, linalool could protect the hypothalamus against METH-induced neurotoxicity and proteome disturbance probably by modifying oxidative stress, neurotransmitters, inflammation, sodium/potassium-ATPase activity, proteome disturbance, and tissue histology in METH-treated rats where higher dose of linalool was more efficient than lower dose.

Immunotherapeutic treatment of inflammation in mice exposed to methamphetamine

Introduction

Currently, there are no FDA-approved medications to treat methamphetamine addiction, including the inflammatory, neurotoxic, and adverse neuropsychiatric effects. We have shown that partial (p)MHC class II constructs (i.e., Recombinant T-cell receptor Ligand - RTL1000), comprised of the extracellular α1 and β1 domains of MHC class II molecules linked covalently to myelin oligodendrocyte glycoprotein (MOG)-35-55 peptide, can address the neuroimmune effects of methamphetamine addiction through its ability to bind to and down-regulate CD74 expression, block macrophage migration inhibitory factor (MIF) signaling, and reduce levels of pro-inflammatory chemokine ligand 2 (CCL2). The present study evaluated the effects of our third-generation pMHC II construct, DRmQ, on cognitive function and concentration of inflammatory cytokines in the frontal cortex, a region critical for cognitive functions such as memory, impulse control, and problem solving.

Methods

Female and male C57BL/6J mice were exposed to methamphetamine (or saline) via subcutaneous (s.c.) injections administered four times per day every other day for 14 days. Following methamphetamine exposure, mice received immunotherapy (DRmQ or ibudilast) or vehicle s.c. injections daily for five days. Cognitive function was assessed using the novel object recognition test (NORT). To evaluate the effects of immunotherapy on inflammation in the frontal cortex, multiplex immunoassays were conducted. ANOVA was used to compare exploration times on the NORT and immune factor concentrations.

Results

Post hoc analysis revealed increased novel object exploration time in MA-DRmQ treated mice, as compared to MA-VEH treated mice (non-significant trend). One-way ANOVA detected a significant difference across the groups in the concentration of macrophage inflammatory protein-2 (MIP-2) (p = 0.03). Post hoc tests indicated that mice treated with methamphetamine and DRmQ or ibudilast had significantly lower levels of MIP-2 in frontal cortex, as compared to mice treated with methamphetamine and vehicle (p > 0.05).

Discussion

By specifically targeting CD74, our DRQ constructs can block the signaling of MIF, inhibiting the downstream signaling and pro-inflammatory effects that contribute to and perpetuate methamphetamine addiction.

Methamphetamine exposure drives cell cycle exit and aberrant differentiation in rat hippocampal-derived neurospheres

Introduction: Methamphetamine (METH) abuse by pregnant drug addicts causes toxic effects on fetal neurodevelopment; however, the mechanism underlying such effect of METH is poorly understood. Methods: In the present study, we applied three-dimensional (3D) neurospheres derived from the embryonic rat hippocampal tissue to investigate the effect of METH on neurodevelopment. Through the combination of whole genome transcriptional analyses, the involved cell signalings were identified and investigated. Results: We found that METH treatment for 24 h significantly and concentration-dependently reduced the size of neurospheres. Analyses of genome-wide transcriptomic profiles found that those down-regulated differentially expressed genes (DEGs) upon METH exposure were remarkably enriched in the cell cycle progression. By measuring the cell cycle and the expression of cell cycle-related checkpoint proteins, we found that METH exposure significantly elevated the percentage of G0/G1 phase and decreased the levels of the proteins involved in the G1/S transition, indicating G0/G1 cell cycle arrest. Furthermore, during the early neurodevelopment stage of neurospheres, METH caused aberrant cell differentiation both in the neurons and astrocytes, and attenuated migration ability of neurospheres accompanied by increased oxidative stress and apoptosis. Conclusion: Our findings reveal that METH induces an aberrant cell cycle arrest and neuronal differentiation, impairing the coordination of migration and differentiation of neurospheres.

The gut microbiota as a potential biomarker for methamphetamine use disorder: evidence from two independent datasets

Background

Methamphetamine use disorder (MUD) poses a considerable public health threat, and its identification remains challenging due to the subjective nature of the current diagnostic system that relies on self-reported symptoms. Recent studies have suggested that MUD patients may have gut dysbiosis and that gut microbes may be involved in the pathological process of MUD. We aimed to examine gut dysbiosis among MUD patients and generate a machine-learning model utilizing gut microbiota features to facilitate the identification of MUD patients.

Method

Fecal samples from 78 MUD patients and 50 sex- and age-matched healthy controls (HCs) were analyzed by 16S rDNA sequencing to identify gut microbial characteristics that could help differentiate MUD patients from HCs. Based on these microbial features, we developed a machine learning model to help identify MUD patients. We also used public data to verify the model; these data were downloaded from a published study conducted in Wuhan, China (with 16 MUD patients and 14 HCs). Furthermore, we explored the gut microbial features of MUD patients within the first three months of withdrawal to identify the withdrawal period of MUD patients based on microbial features.

Results

MUD patients exhibited significant gut dysbiosis, including decreased richness and evenness and changes in the abundance of certain microbes, such as Proteobacteria and Firmicutes. Based on the gut microbiota features of MUD patients, we developed a machine learning model that demonstrated exceptional performance with an AUROC of 0.906 for identifying MUD patients. Additionally, when tested using an external and cross-regional dataset, the model achieved an AUROC of 0.830. Moreover, MUD patients within the first three months of withdrawal exhibited specific gut microbiota features, such as the significant enrichment of Actinobacteria. The machine learning model had an AUROC of 0.930 for identifying the withdrawal period of MUD patients.

Conclusion

In conclusion, the gut microbiota is a promising biomarker for identifying MUD and thus represents a potential approach to improving the identification of MUD patients. Future longitudinal studies are needed to validate these findings.

Improving behavioral test data collection and analysis in animal models with an image processing program

Behavioral studies are commonly used as a standard procedure to evaluate anxiety and depression in animal models. Recently, different methods have been developed to improve data collection and analysis of the behavioral tests. Currently available methods, including manual analysis and commercially available products, are either time-consuming or costly. The objective of this study was to improve the collection and analysis of behavioral test data in animal models by developing an image processing program. Eleven behavioral parameters were evaluated by three different methods, including (i) manual detection, (ii) commercially available TopScan software (CleverSys Inc, USA), and (iii) In-housed-developed Advanced Move Tracker (AMT) software. Results obtained from different methods were compared to validate the accuracy and efficiency of AMT. Results showed that AMT software provides highly accurate and reliable data analysis compared to other methods. Less than 5% tolerance was reported between results obtained from AMT compared to TopScan. In addition, the analysis processing time was remarkably reduced (68.3%) by using AMT compared to manual detection. Overall, the findings confirmed that AMT is an efficient program for automated data analysis, significantly enhancing research outcomes through accurate analysis of behavioral test data in animal models.

Tryptophan and Substance Abuse: Mechanisms and Impact

Addiction, the continuous misuse of addictive material, causes long-term dysfunction in the neurological system. It substantially affects the control strength of reward, memory, and motivation. Addictive substances (alcohol, marijuana, caffeine, heroin, methamphetamine (METH), and nicotine) are highly active central nervous stimulants. Addiction leads to severe health issues, including cardiovascular diseases, serious infections, and pulmonary/dental diseases. Drug dependence may result in unfavorable cognitive impairments that can continue during abstinence and negatively influence recovery performance. Although addiction is a critical global health challenge with numerous consequences and complications, currently, there are no efficient options for treating drug addiction, particularly METH. Currently, novel treatment approaches such as psychological contingency management, cognitive behavioral therapy, and motivational enhancement strategies are of great interest. Herein, we evaluate the devastating impacts of different addictive substances/drugs on users' mental health and the role of tryptophan in alleviating unfavorable side effects. The tryptophan metabolites in the mammalian brain and their potential to treat compulsive abuse of addictive substances are investigated by assessing the functional effects of addictive substances on tryptophan. Future perspectives on developing promising modalities to treat addiction and the role of tryptophan and its metabolites to alleviate drug dependency are discussed.

Immunotherapies for the Treatment of Drug Addiction

Substance use disorders (SUD) are a serious public health concern globally. Existing treatment platforms suffer from a lack of effectiveness. The development of immunotherapies against these substances of abuse for both prophylactic and therapeutic use has gained tremendous importance as an alternative and/or supplementary to existing therapies. Significant development has been made in this area over the last few decades. Herein, we highlight the vaccine and other biologics development strategies, preclinical, clinical updates along with challenges and future directions. Articles were searched in PubMed, ClinicalTrial.gov, and google electronic databases relevant to development, preclinical, clinical trials of nicotine, cocaine, methamphetamine, and opioid vaccines. Various new emerging vaccine development strategies for SUD were also identified through this search and discussed. A good number of vaccine candidates demonstrated promising results in preclinical and clinical phases and support the concept of developing a vaccine for SUD. However, there have been no ultimate success as yet, and there remain some challenges with a massive push to take more candidates to clinical trials for further evaluation to break the bottleneck.