Parkinson's Disease-Related Biomarkers That May Appear in Amphetamine Abusers

Long-term disruption of tissue levels of glutamate and glutamatergic neurotransmission neuromodulators, taurine and kynurenic acid induced by amphetamine

RATIONALE

Chronic amphetamine (AMPH) use leading to addiction results in adaptive changes within the central nervous system that persist well beyond the drug's elimination from the body and can precipitate relapse. Notably, alterations in glutamatergic neurotransmission play a crucial role in drug-associated behaviours.

OBJECTIVES

This study aimed to identify changes induced by amphetamine in glutamate levels and the neuromodulators of glutamatergic neurotransmission (taurine and kynurenic acid) observable after 14 and 28 days of abstinence in key brain regions implicated in addiction: the cortex (Cx), nucleus accumbens (Acb), and dorsolateral striatum (CPu-L).

METHODS

The rats were administered 12 doses of amphetamine (AMPH) intraperitoneally (i.p.) at 1.5 mg/kg. The behavioural response was evaluated through ultrasonic vocalizations (USV). High-performance liquid chromatography (HPLC) was used to measure the levels of glutamate, taurine, and kynurenic acid in the Cx, Acb, and CPu-L after 14 and 28 days of abstinence.

RESULTS

AMPH administration led to sensitisation towards AMPH's rewarding effects, as evidenced by changes in USV. There was a noticeable decrease in kynurenic acid levels and an increase in both taurine and glutamate in the CPu-L, along with an increase in glutamate levels in the Cx, 28 days following the final AMPH injection.

CONCLUSIONS

The most significant changes in the tissue levels of glutamate, taurine, and kynurenic acid were seen in the CPu-L 28 days after the last dose of AMPH. The emergence of these changes exclusively after 28 days suggests that the processes initiated by AMPH use and subsequent abstinence take time to become apparent and may be enduring. This could contribute to the incubation of craving and the risk of relapse. Developing pharmacological strategies to counteract the reduction in kynurenic acid induced by psychostimulants may provide new avenues for therapy development.

DReAmocracy: A Method to Capitalise on Prior Drug Discovery Efforts to Highlight Candidate Drugs for Repurposing

In the area of drug research, several computational drug repurposing studies have highlighted candidate repurposed drugs, as well as clinical trial studies that have tested/are testing drugs in different phases. To the best of our knowledge, the aggregation of the proposed lists of drugs by previous studies has not been extensively exploited towards generating a dynamic reference matrix with enhanced resolution. To fill this knowledge gap, we performed weight-modulated majority voting of the modes of action, initial indications and targeted pathways of the drugs in a well-known repository, namely the Drug Repurposing Hub. Our method, DReAmocracy, exploits this pile of information and creates frequency tables and, finally, a disease suitability score for each drug from the selected library. As a testbed, we applied this method to a group of neurodegenerative diseases (Alzheimer's, Parkinson's, Huntington's disease and Multiple Sclerosis). A super-reference table with drug suitability scores has been created for all four neurodegenerative diseases and can be queried for any drug candidate against them. Top-scored drugs for Alzheimer's Disease include agomelatine, mirtazapine and vortioxetine; for Parkinson's Disease, they include apomorphine, pramipexole and lisuride; for Huntington's, they include chlorpromazine, fluphenazine and perphenazine; and for Multiple Sclerosis, they include zonisamide, disopyramide and priralfimide. Overall, DReAmocracy is a methodology that focuses on leveraging the existing drug-related experimental and/or computational knowledge rather than a predictive model for drug repurposing, offering a quantified aggregation of existing drug discovery results to (1) reveal trends in selected tracks of drug discovery research with increased resolution that includes modes of action, targeted pathways and initial indications for the investigated drugs and (2) score new candidate drugs for repurposing against a selected disease.

Elevated C-reactive protein/albumin ratio in patients with methamphetamine use disorder

BACKGROUND

Methamphetamine use disorder causes significant crises, which have individual, familial, and social consequences. Identifying inflammatory biomarkers for methamphetamine use disorder may be useful for following the inflammatory status of patients in clinical assessment. In this study, we aimed to investigate whether neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), monocyte/lymphocyte ratio (MLR), C-reactive protein/albumin ratio (CAR) and neutrophil/albumin ratio (NAR) levels can be used as inflammatory biomarkers in methamphetamine use disorder.

METHODS

The sample comprised 139 treatment-seeking participants who met the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for methamphetamine use disorder and 139 sociodemographically matched controls. Only hospitalised patients were included. An independent sample t-test, Pearson's correlation test, and binominal logistic regression analysis were performed.

RESULTS

CAR (p = 0.016) and NAR (p = 0.048) levels were significantly higher in individuals with methamphetamine use disorder when compared with healthy controls. The CAR level was found to be a significant predictor of group membership in regression analysis for methamphetamine use disorder.

CONCLUSION

CAR may be a potential inflammatory biomarker for patients with methamphetamine use disorder. CAR as a relatively easier-to-measure biomarker could be beneficial to follow the inflammatory status and treatment response of patients.

Serum amyloid P component and pro-platelet basic protein in extracellular vesicles or serum are novel markers of liver fibrosis in chronic hepatitis C patients

Extracellular vesicles (EVs) contain proteins, mRNAs, and microRNAs, and their cargos have emerged as novel diagnostic markers in various diseases. We aimed to discover novel and noninvasive biomarkers of liver fibrosis by proteomic analysis using serum EVs in patients with chronic hepatitis C. We performed shotgun proteomics using serum EVs isolated from 54 patients with histologically assessed liver fibrosis. Shotgun proteomics identified a total of 974 proteins, and 445 proteins were detected in more than half of the patients. Among them, a total of 9 proteins were identified as proteins that tended to increase or decrease with liver fibrosis with a significance of p<0.005 and that were different between F1-2 patients and F3-4 patients with a significance of p<0.01. Among the 9 proteins, targeted proteomics using serum EVs isolated from the sera of another 80 patients with histologically assessed liver fibrosis verified that serum amyloid P component (SAP) and pro-platelet basic protein (PPBP) levels in EVs significantly decreased with the progression of liver fibrosis and were significantly lower in F3-4 patients than in F1-2 patients. The diagnostic accuracies of SAP and PPBP in EVs for the liver fibrosis stage were comparable to those of type IV collagen 7S, hyaluronic acid, and the fibrosis-4 index (FIB-4 index). Moreover, serum SAP and PPBP levels correlated with the levels in EVs, and the ability of serum SAP and PPBP to diagnose liver fibrosis stage was also comparable to the abilities of type IV collagen 7S, hyaluronic acid, and the FIB-4 index. In conclusion, proteomic analysis of serum EVs identified SAP and PPBP as candidate biomarkers for predicting liver fibrosis in patients with chronic hepatitis C. In addition, SAP and PPBP levels in serum are strongly correlated with those in EVs and could represent markers of liver fibrosis.

Increased Inflammatory Markers at AMPH-Addicts Are Related to Neurodegenerative Conditions: Alzheimer’s Disease

Amphetamine addiction is widespread worldwide despite causing severe physical and mental problems, including neurodegeneration. One of the most common neurodegenerative disorders is Alzheimer’s disease (AD). Several inflammatory markers have been linked to AD. Previous studies have also found these biomarkers in amphetamine-addicts (AMPH-add). This study thus seeks to understand how AD and AMPH-addiction are related. A case–control observational study was conducted. Seventeen AMPH-adds ranging in age from 23 to 40 were recruited from Al Amal Psychiatric Hospital. In addition, 19 healthy subjects matching their age and gender were also recruited. The Luminex technique was used to measure serum alpha 1 antichymotrypsin (ACT), pigment epithelium-derived factor (PEDF), and macrophage inflammatory protein-4 (MIP-4), after complying with ethical guidelines and obtaining informed consent. In addition, liver function enzymes were correlated to AD’s predictive biomarkers in AMPH-adds. AMPH-adds had significantly higher serum levels of ACT, PEDF, and MIP-4 when compared to healthy controls (p = 0.03, p = 0.001, and p = 0.012, respectively). Furthermore, there is a significant correlation between lower ALT levels and elevated AST to ALT ratios in AMPH-adds (r = 0.618, 0.651, and p = 0.0001). These changes in inflammatory biomarkers may be linked to the onset of AD at a young age in amphetamine-drug addicts.