Lipids and drugs of abuse

The Inflammatory Signals Associated with Psychosis: Impact of Comorbid Drug Abuse

Psychosis and substance use disorders are two diagnostic categories whose association has been studied for decades. In addition, both psychosis spectrum disorders and drug abuse have recently been linked to multiple pro-inflammatory changes in the central nervous system. We have carried out a narrative review of the literature through a holistic approach. We used PubMed as our search engine. We included in the review all relevant studies looking at pro-inflammatory changes in psychotic disorders and substance use disorders. We found that there are multiple studies that relate various pro-inflammatory lipids and proteins with psychosis and substance use disorders, with an overlap between the two. The main findings involve inflammatory mediators such as cytokines, chemokines, endocannabinoids, eicosanoids, lysophospholipds and/or bacterial products. Many of these findings are present in different phases of psychosis and in substance use disorders such as cannabis, cocaine, methamphetamines, alcohol and nicotine. Psychosis and substance use disorders may have a common origin in an abnormal neurodevelopment caused, among other factors, by a neuroinflammatory process. A possible convergent pathway is that which interrelates the transcriptional factors NFκB and PPARγ. This may have future clinical implications.

Simvastatin Blocks Reinstatement of Cocaine-induced Conditioned Place Preference in Male Mice with Brain Lipidome Remodeling

Drug-associated reward memories are conducive to intense craving and often trigger relapse. Simvastatin has been shown to regulate lipids that are involved in memory formation but its influence on other cognitive processes is elusive. Here, we used a mass spectrometry-based lipidomic method to evaluate the impact of simvastatin on the mouse brain in a cocaine-induced reinstatement paradigm. We found that simvastatin blocked the reinstatement of cocaine-induced conditioned place preference (CPP) without affecting CPP acquisition. Specifically, only simvastatin administered during extinction prevented cocaine-primed reinstatement. Global lipidome analysis showed that the nucleus accumbens was the region with the greatest degree of change caused by simvastatin. The metabolism of fatty-acids, phospholipids, and triacylglycerol was profoundly affected. Simvastatin reversed most of the effects on phospholipids induced by cocaine. The correlation matrix showed that cocaine and simvastatin significantly reshaped the lipid metabolic pathways in specific brain regions. Furthermore, simvastatin almost reversed all changes in the fatty acyl profile and unsaturation caused by cocaine. In summary, pre-extinction treatment with simvastatin facilitates cocaine extinction and prevents cocaine relapse with brain lipidome remodeling.

Metabolic phenotyping of opioid and psychostimulant addiction: A novel approach for biomarker discovery and biochemical understanding of the disorder

Despite the progress in characterising the pharmacological profile of drugs of abuse, their precise biochemical impact remains unclear. The metabolome reflects the multifaceted biochemical processes occurring within a biological system. This includes those encoded in the genome but also those arising from environmental/exogenous exposures and interactions between the two. Using metabolomics, the biochemical derangements associated with substance abuse can be determined as the individual transitions from recreational drug to chronic use (dependence). By understanding the biomolecular perturbations along this time course and how they vary across individuals, metabolomics can elucidate biochemical mechanisms of the addiction cycle (dependence/withdrawal/relapse) and predict prognosis (recovery/relapse). In this review, we summarise human and animal metabolomic studies in the field of opioid and psychostimulant addiction. We highlight the importance of metabolomics as a powerful approach for biomarker discovery and its potential to guide personalised pharmacotherapeutic strategies for addiction targeted towards the individual's metabolome.

Repeated Administration of Clinical Doses of Tramadol and Tapentadol Causes Hepato- and Nephrotoxic Effects in Wistar Rats

Tramadol and tapentadol are fully synthetic and extensively used analgesic opioids, presenting enhanced therapeutic and safety profiles as compared with their peers. However, reports of adverse reactions, intoxications and fatalities have been increasing. Information regarding the molecular, biochemical, and histological alterations underlying their toxicological potential is missing, particularly for tapentadol, owing to its more recent market authorization. Considering the paramount importance of liver and kidney for the metabolism and excretion of both opioids, these organs are especially susceptible to toxicological damage. In the present study, we aimed to characterize the putative hepatic and renal deleterious effects of repeated exposure to therapeutic doses of tramadol and tapentadol, using an in vivo animal model. Male Wistar rats were randomly divided into six experimental groups, composed of six animals each, which received daily single intraperitoneal injections of 10, 25 or 50 mg/kg tramadol or tapentadol (a low, standard analgesic dose, an intermediate dose and the maximum recommended daily dose, respectively). An additional control group was injected with normal saline. Following 14 consecutive days of administration, serum, urine and liver and kidney tissue samples were processed for biochemical, metabolic and histological analysis. Repeated administration of therapeutic doses of both opioids led to: (i) increased lipid and protein oxidation in liver and kidney, as well as to decreased total liver antioxidant capacity; (ii) decreased serum albumin, urea, butyrylcholinesterase and complement C3 and C4 levels, denoting liver synthesis impairment; (iii) elevated serum activity of liver enzymes, such as alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and γ-glutamyl transpeptidase, as well as lipid profile alterations, also reflecting hepatobiliary commitment; (iv) derangement of iron metabolism, as shown through increases in serum iron, ferritin, haptoglobin and heme oxygenase-1 levels. In turn, elevated serum cystatin C, decreased urine creatinine output and increased urine microalbumin levels were detected upon exposure to tapentadol only, while increased serum amylase and urine N-acetyl-β-D-glucosaminidase activities were observed for both opioids. Collectively, these results are compatible with kidney injury. Changes were also found in the expression levels of liver- and kidney-specific toxicity biomarker genes, upon exposure to tramadol and tapentadol, correlating well with alterations in lipid profile, iron metabolism and glomerular and tubular function. Histopathological analysis evidenced sinusoidal dilatation, microsteatosis, mononuclear cell infiltrates, glomerular and tubular disorganization, and increased Bowman's spaces. Although some findings are more pronounced upon tapentadol exposure, our study shows that, when compared with acute exposure, prolonged administration of both opioids smooths the differences between their toxicological effects, and that these occur at lower doses within the therapeutic range.

Lipidomic changes in the rat hippocampus following cocaine conditioning, extinction, and reinstatement of drug-seeking

INTRODUCTION

Cocaine dependence affects millions of individuals worldwide; however, there are no pharmacotherapeutic and/or diagnostic solutions. Recent evidence suggests a role for lipid signaling in the development and maintenance of addiction, highlighting the need to understand how lipid remodeling mediates neuroadaptation after cocaine exposure.

METHODS

This study utilized shotgun lipidomics to assess cocaine-induced lipid remodeling in rats using a novel behavioral regimen that incorporated multiple sessions of extinction training and reinstatement testing.

RESULTS

Mass spectrometric imaging demonstrated widespread decreases in phospholipid (PL) abundance throughout the brain, and high-spatial resolution matrix-assisted laser desorption/ionization Fourier-transform ion cyclotron resonance mass spectrometry indicated hippocampus-specific PL alterations following cocaine exposure. We analyzed the expression of genes involved in hippocampal lipid metabolism and observed region-specific regulation. In addition, we found that cocaine exposure differentially regulates mitochondrial biogenesis in the brain.

CONCLUSIONS

This work presents a comprehensive lipidomic assessment of cocaine-induced lipid remodeling in the rat brain. Further, these findings indicate a potential interplay between CNS energetics and differential lipid regulation and suggest a role for cocaine in the maintenance of energy homeostasis.

Plant-Based Modulators of Endocannabinoid Signaling

Extracts from Cannabis species have aided the discovery of the endocannabinoid signaling system (ECSS) and phytocannabinoids that possess broad therapeutic potential. Whereas the reinforcing effects of C. sativa are largely attributed to CB1 receptor agonism by Δ⁹-tetrahydrocannabinol (Δ⁹-THC), the observed medicinal effects of Cannabis arise from the combined actions of various compounds. In addition to compounds bearing a classical cannabinoid structure, naturally occurring fatty acid amides and esters resembling anandamide and 2-arachidonoyl glycerol isolated from non- Cannabis species are also valuable tools for studying ECSS function. This review highlights the potential of plant-based secondary metabolites from Cannabis and unrelated species as ECSS modulators.

Cardiovascular complications and related risk factors underlying opium consumption

Opium is considered as the second most abused addictive compound in worldwide. It seems that one of the causes for common consumption of opium in many countries is a traditional belief, even among medical personnel, through which opium might have advantageous influences on cardiovascular events and be beneficial in controlling hypertension, dyslipidemia, and diabetes. According to several investigations, it is thought that opium not only has no beneficial effects on cardiovascular events, but it might have deleterious influences on these settings. As a result, people need to be trained with regard to the adverse effects of opium on cardiovascular events. In this review, we try to go through the understanding of the effects of opium cardiovascular disorders and related complications such as blood pressure, blood sugar, lipid circumstances, and finally atherosclerosis.

The Impact of Opium Consumption on Blood Glucose, Serum Lipids and Blood Pressure, and Related Mechanisms

Aim: Substance abuse has become a universal crisis in our modern age. Among illegal substances, opium and its derivatives have been ranked second in terms of usage after cannabis in the world. In many Asian regions, the use of opium enjoys a high social acceptance; hence, some common people and even medical practitioners believe that opium lowers blood glucose and pressure and treat dyslipidemia. How much this belief is scientifically justified?

Method: The results of available studies on both humans and animals searched in different search engines up to mid-2016 were integrated (78 articles). Upon the findings we try to offer a more transparent picture of the effects of opium on the mentioned factors along with the probable underlying mechanisms of its action.

Results: Taken together, a variety of evidences suggest that the consumption of opium has no scientific justification for amendment of these biochemical variables. The mechanisms proposed so far for the action of opium in the three above disorders are summarized at the end of the article. Short term effects seems to be mostly mediated through central nervous system (neural and hormonal mechanisms), but long term effects are often due to the structural and functional alterations in some body organs.

Conclusion: Although opium may temporarily reduce blood pressure, but it increases blood glucose and most of blood lipids. Moreover its long term use has negative impacts and thus it aggravates diabetes, dyslipidemia and hypertension. Accordingly, it is necessary to inform societies about the potential disadvantages of unauthorized opium consumption.

Effects of opium consumption on cardiometabolic diseases

Opium is the second-most-commonly abused substance (after tobacco) in developing countries of the Middle East region, and in many Asian nations. One of the reasons for the high prevalence of opium abuse in these countries is a traditional belief among Eastern people, even including some medical staff, that opium might have beneficial effects on cardiovascular health and in the control of diabetes mellitus, hypertension, and dyslipidaemia. In this Perspectives article, we summarize the current understanding of the pharmacotoxicology of opium and its specific effects on glycaemic control, blood pressure, lipid profile, and atherosclerosis. On the basis of the available evidence, we believe not only that opium has no ameliorating effect on cardiovascular diseases, but also that the use of this drug might have adverse effects on these conditions. Therefore, people should be educated about the hazardous effects of opium consumption on cardiometabolic diseases.

Association between cholesterol plasma levels and craving among heroin users

OBJECTIVE

Lipids may play some roles in the central nervous system functions that are associated with drug addiction. To date, cholesterol is known to influence relapse of cocaine use. However, the relationship between cholesterol and heroin craving is unclear. This study examined the concurrent association between cholesterol and craving.

METHOD

The serum lipid levels of 70 heroin users who were undergoing or had undergone a methadone maintenance therapy were measured. Their craving and demographic data were assessed.

RESULTS

Total cholesterol and low-density lipoprotein cholesterol are negatively associated with craving before (r = -0.33, P < 0.01, and r = -0.36, P < 0.01, respectively) and after controlling for the effects of potential confounders (β = -0.38, P < 0.01, and β = -0.42, P < 0.01, respectively).

CONCLUSIONS

Cholesterol could be associated with the cognitive aspect of craving and may be a potential marker to predict risk of drug relapse.

Essential fatty acids and attention-deficit-hyperactivity disorder: a systematic review

AIM

Essential fatty acids (EFAs), also known as omega-3 and omega-6 fatty acids, have been claimed to have beneficial effects as a treatment for attention-deficit-hyperactivity disorder (ADHD). Animal experiments have provided information about the role of EFA in the brain, and several mechanisms of EFA activity are well known. The current review provides an updated, systematic overview of the theory and use of EFA in ADHD.

METHOD

Clinical studies and review papers of EFA blood levels and EFA supplementation trials in children with ADHD were researched in the Medline PubMed database. Additional studies were found from the references of these reports.

RESULTS

Children with ADHD present lower levels of blood EFAs, and open-label EFA supplementation trials in ADHD raise EFA blood levels and improve symptoms of ADHD. Randomized controlled trials, however, have generally been unsuccessful in demonstrating any behavioural treatment effects.

INTERPRETATION

Current findings do not support the use of EFA supplements as a primary or supplementary treatment for children with ADHD.

Analytical strategies in lipidomics and applications in disease biomarker discovery

Lipidomics is a lipid-targeted metabolomics approach aiming at comprehensive analysis of lipids in biological systems. Recently, lipid profiling, or so-called lipidomics research, has captured increased attention due to the well-recognized roles of lipids in numerous human diseases to which lipid-associated disorders contribute, such as diabetes, obesity, atherosclerosis and Alzheimer's disease. Investigating lipid biochemistry using a lipidomics approach will not only provide insights into the specific roles of lipid molecular species in health and disease, but will also assist in identifying potential biomarkers for establishing preventive or therapeutic approaches for human health. Recent technological advancements in mass spectrometry and rapid improvements in chromatographic techniques have led to the rapid expansion of the lipidomics research field. In this review, emphasis is given to the recent advances in lipidomics technologies and their applications in disease biomarker discovery.

Role of Lipids in Brain Injury and Diseases

Lipid metabolism is of particular interest due to its high concentration in CNS. The importance of lipids in cell signaling and tissue physiology is demonstrated by many CNS disorders and injuries that involve deregulated metabolism. The long suffering lipid field is gaining reputation and respect as evidenced through the Center of Biomedical Research Excellence in Lipidomics and Pathobiology (COBRE), Lipid MAPS (Metabolites And Pathways Strategy) Consortium sponsored by NIH, European initiatives for decoding the lipids through genomic approaches, and Genomics of Lipid-associated Disorder (GOLD) project initiated by Austrian government. This review attempts to provide an overview of the lipid imbalances associated with neurological disorders (Alzheimer's, Parkinson's; Niemann-Pick; Multiple sclerosis, Huntington, amyotrophic lateral sclerosis, schizophrenia, bipolar disorders and epilepsy) and CNS injury (Stroke, traumatic brain injury; and spinal cord injury) and a few provocative thoughts. Lipidomic analyses along with RNA silencing will provide new insights into the role of lipid intermediates in cell signaling and hopefully open new avenues for prevention or treatment options.

Lipids and lipidomics in brain injury and diseases

Lipidomics is systems-level analysis and characterization of lipids and their interacting moieties. The amount of information in the genomic and proteomic fields is greater than that in the lipidomics field, because of the complex nature of lipids and the limitations of tools for analysis. The main innovation during recent years that has spurred advances in lipid analysis has been the development of new mass spectroscopic techniques, particularly the "soft ionization" techniques electrospray ionization and matrix-assisted laser desorption/ionization. Lipid metabolism may be of particular importance for the central nervous system, as it has a high concentration of lipids. The crucial role of lipids in cell signaling and tissue physiology is demonstrated by the many neurological disorders, including bipolar disorders and schizophrenia, and neurodegenerative diseases such as Alzheimer's, Parkinson's, and Niemann-Pick diseases, that involve deregulated lipid metabolism. Altered lipid metabolism is also believed to contribute to cerebral ischemic (stroke) injury. Lipidomics will provide a molecular signature to a certain pathway or a disease condition. Lipidomic analyses (characterizing complex mixtures of lipids and identifying previously unknown changes in lipid metabolism) together with RNA silencing, using small interfering RNA (siRNA), may provide powerful tools to elucidate the specific roles of lipid intermediates in cell signaling and open new opportunities for drug development.