Sexual Dimorphism in Energy Metabolism of Wistar Rats Using Data Analysis

Tackling new psychoactive substances through metabolomics: UHPLC-HRMS study on natural and synthetic opioids in male and female murine models

Novel psychoactive substances (NPS) represent a broad class of drugs new to the illicit market that often allow passing drug-screening tests. They are characterized by a variety of structures, rapid transience on the drug scene and mostly unknown metabolic profiles, thus creating an ever-changing scenario with evolving analytical targets. The present study aims at developing an indirect screening strategy for NPS monitoring, and specifically for new synthetic opioids (NSOs), based on assessing changes in endogenous urinary metabolite levels as a consequence of the systemic response following their intake. The experimental design involved in-vivo mice models: 16 animals of both sex received a single administration of morphine or fentanyl. Urine was collected before and after administration at different time points; the samples were then analysed with an untargeted metabolomics LC-HRMS workflow. According to our results, the intake of opioids resulted in an elevated energy demand, that was more pronounced on male animals, as evidenced by the increase in medium and long chain acylcarnitines levels. It was also shown that opioid administration disrupted the pathways related to catecholamines biosynthesis. The observed alterations were common to both morphine and fentanyl: this evidence indicate that they are not related to the chemical structure of the drug, but rather on the drug class. The proposed strategy may reinforce existing NPS screening approaches, by identifying indirect markers of drug assumption.

Metabolomics in Animal Models of Bronchial Asthma and Its Translational Importance for Clinics

Bronchial asthma is an extremely heterogenous chronic respiratory disorder with several distinct endotypes and phenotypes. These subtypes differ not only in the pathophysiological changes and/or clinical features but also in their response to the treatment. Therefore, precise diagnostics represent a fundamental condition for effective therapy. In the diagnostic process, metabolomic approaches have been increasingly used, providing detailed information on the metabolic alterations associated with human asthma. Further information is brought by metabolomic analysis of samples obtained from animal models. This article summarizes the current knowledge on metabolomic changes in human and animal studies of asthma and reveals that alterations in lipid metabolism, amino acid metabolism, purine metabolism, glycolysis and the tricarboxylic acid cycle found in the animal studies resemble, to a large extent, the changes found in human patients with asthma. The findings indicate that, despite the limitations of animal modeling in asthma, pre-clinical testing and metabolomic analysis of animal samples may, together with metabolomic analysis of human samples, contribute to a novel way of personalized treatment of asthma patients.

Untargeted metabonomic analysis of a cerebral stroke model in rats: a study based on UPLC-MS/MS

Introduction

Brain tissue damage caused by ischemic stroke can trigger changes in the body's metabolic response, and understanding the changes in the metabolic response of the gut after stroke can contribute to research on poststroke brain function recovery. Despite the increase in international research on poststroke metabolic mechanisms and the availability of powerful research tools in recent years, there is still an urgent need for poststroke metabolic studies. Metabolomic examination of feces from a cerebral ischemia-reperfusion rat model can provide new insights into poststroke metabolism and identify key metabolic pathways, which will help reveal diagnostic and therapeutic targets as well as inspire pathophysiological studies after stroke.

Methods

We randomly divided 16 healthy adult pathogen-free male Sprague-Dawley (SD) rats into the normal group and the study group, which received middle cerebral artery occlusion/reperfusion (MCAO/R). Ultra-performance liquid chromatography-tandem mass spectrometry (UPLCMS/MS) was used to determine the identities and concentrations of metabolites across all groups, and filtered high-quality data were analyzed for differential screening and differential metabolite functional analysis.

Results

After 1 and 14 days of modeling, compared to the normal group, rats in the study group showed significant neurological deficits (p < 0.001) and significantly increased infarct volume (day 1: p < 0.001; day 14: p = 0.001). Mass spectra identified 1,044 and 635 differential metabolites in rat feces in positive and negative ion modes, respectively, which differed significantly between the normal and study groups. The metabolites with increased levels identified in the study group were involved in tryptophan metabolism (p = 0.036678, p < 0.05), arachidonic acid metabolism (p = 0.15695), cysteine and methionine metabolism (p = 0.24705), and pyrimidine metabolism (p = 0.3413), whereas the metabolites with decreased levels were involved in arginine and proline metabolism (p = 0.15695) and starch and sucrose metabolism (p = 0.52256).

Discussion

We determined that UPLC-MS/MS could be employed for untargeted metabolomics research. Moreover, tryptophan metabolic pathways may have been disordered in the study group. Alterations in the tryptophan metabolome may provide additional theoretical and data support for elucidating stroke pathogenesis and selecting pathways for intervention.

Slow or fast: Implications of myofibre type and associated differences for manifestation of neuromuscular disorders

Many neuromuscular disorders can have a differential impact on a specific myofibre type, forming the central premise of this review. The many different skeletal muscles in mammals contain a spectrum of slow- to fast-twitch myofibres with varying levels of protein isoforms that determine their distinctive contractile, metabolic, and other properties. The variations in functional properties across the range of classic 'slow' to 'fast' myofibres are outlined, combined with exemplars of the predominantly slow-twitch soleus and fast-twitch extensor digitorum longus muscles, species comparisons, and techniques used to study these properties. Other intrinsic and extrinsic differences are discussed in the context of slow and fast myofibres. These include inherent susceptibility to damage, myonecrosis, and regeneration, plus extrinsic nerves, extracellular matrix, and vasculature, examined in the context of growth, ageing, metabolic syndrome, and sexual dimorphism. These many differences emphasise the importance of carefully considering the influence of myofibre-type composition on manifestation of various neuromuscular disorders across the lifespan for both sexes. Equally, understanding the different responses of slow and fast myofibres due to intrinsic and extrinsic factors can provide deep insight into the precise molecular mechanisms that initiate and exacerbate various neuromuscular disorders. This focus on the influence of different myofibre types is of fundamental importance to enhance translation for clinical management and therapies for many skeletal muscle disorders.

Metabolic study of new psychoactive substance methoxpropamine in mice by UHPLC-QTOF-HRMS

Methoxpropamine (MXPr) is an arylcyclohexylamine dissociative drug structurally similar to 3-methoxyeticyclidine, ketamine, and deschloroketamine, recently appeared in the European illegal market, and was classified within the new psychoactive substances (NPS). Our study investigated the metabolism of MXPr to elucidate the distribution of the parent drug and its metabolites in body fluids and fur of 16 mice. After the intraperitoneal administration of MXPr (1, 3, and 10 mg/kg), urine samples from eight male and eight female mice were collected every hour for six consecutive hours and then at 12- to 24-h intervals. Additionally, plasma samples were collected 24 h after MXPr (1 and 3 mg/kg) administration. Urine and plasma were diluted 1:3 with acetonitrile/methanol (95:5) and directly injected into the UHPLC-QTOF-HRMS system. The phase-I and phase-II metabolites were preliminarily identified by means of the fragmentation patterns and the exact masses of both their precursor and fragment ions. Lastly, the mice fur was analyzed following an extraction procedure specific for the keratin matrix. Desmethyl-MXPr-glucoronide was identified in urine as the main metabolite, detected up to 24 h after administration. The presence of norMXPr in urine, plasma, and fur was also relevant, following a N-dealkylation process of the parent drug. Other metabolites that were identified in fur and plasma included desmethyl-MXPr and dihydro-MXPr. Knowledge of the MXPr metabolites evolution is likely to support their introduction as target compounds in NPS toxicological screening analysis on real samples, both to confirm intake and extend the detection window of the dissociative drug MXPr in the biological matrices.

Biochemical Properties of Atranorin-Induced Behavioral and Systematic Changes of Laboratory Rats

Atranorin (ATR) is a secondary metabolite of lichens. While previous studies investigated the effects of this substance predominantly in an in vitro environment, in our study we investigated the basic physicochemical properties, the binding affinity to human serum albumin (HSA), basic pharmacokinetics, and, mainly, on the systematic effects of ATR in vivo. Sporadic studies describe its effects during, predominantly, cancer. This project is original in terms of testing the efficacy of ATR on a healthy organism, where we can possibly attribute negative effects directly to ATR and not to the disease. For the experiment, 24 Sprague Dawley rats (Velaz, Únetice, Czech Republic) were used. The animals were divided into four groups. The first group (n = 6) included healthy males as control intact rats (♂INT) and the second group (n = 6) included healthy females as control intact rats (♀INT). Groups three and four (♂ATR/n = 6 and ♀ATR/n = 6) consisted of animals with daily administered ATR (10mg/kg body weight) in an ethanol-water solution per os for a one-month period. Our results demonstrate that ATR binds to HSA near the binding site TRP214 and acts on a systemic level. ATR caused mild anemia during the treatment. However, based on the levels of hepatic enzymes in the blood (ALT, ALP, or bilirubin levels), thiobarbituric acid reactive substances (TBARS), or liver histology, no impact on liver was recorded. Significantly increased creatinine and lactate dehydrogenase levels together with increased defecation activity during behavioral testing may indicate the anabolic effect of ATR in skeletal muscles. Interestingly, ATR changed some forms of behavior. ATR at a dose of 10 mg/kg body weight is non-toxic and, therefore, could be used in further research.

Understanding gut-liver axis nitrogen metabolism in Fatty Liver Disease

The homeostasis of the most important nitrogen-containing intermediates, ammonia and glutamine, is a tightly regulated process in which the gut-liver axis plays a central role. Several studies revealed that nitrogen metabolism is altered in Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD), a consensus-driven novel nomenclature for Non-Alcoholic Fatty Liver Disease (NAFLD), the most common chronic liver disease worldwide. Both increased ammonia production by gut microbiota and decreased ammonia hepatic removal due to impaired hepatic urea cycle activity or disrupted glutamine synthetase activity may contribute to hepatic ammonia accumulation underlying steatosis, which can eventually progress to hyperammonemia in more advanced stages of steatohepatitis and overt liver fibrosis. Furthermore, our group recently showed that augmented hepatic ammoniagenesis via increased glutaminase activity and overexpression of the high activity glutaminase 1 isoenzyme occurs in Fatty Liver Disease. Overall, the improved knowledge of disrupted nitrogen metabolism and metabolic miscommunication between the gut and the liver suggests that the reestablishment of altered gut-liver axis nitrogenous balance is an appealing and attractive therapeutic approach to tackle Fatty Liver Disease, a growing and unmet health problem.

Strain-Specific Liver Metabolite Profiles in Medaka

The relationship between genetic variation and phenotypic traits is often poorly understood since specific genotypes do not always easily translate into associated phenotypes, especially for complex disorders. The genetic background has been shown to affect metabolic pathways and thus contribute to variations in the metabolome. Here, we tested the suitability of NMR metabolomics for comparative analysis of fish lines as a first step towards phenotype-genotype association studies. The Japanese rice fish, medaka (Oryzias latipes), is a widely used genetic vertebrate model with several isogenic inbred laboratory strains. We used liver extracts of medaka iCab and HO5 strains as a paradigm to test the feasibility of distinguishing the metabolome of two different inbred strains. Fifteen metabolites could be detected in uni- and multivariate analyses that showed strain-specific levels. Differences could be assigned to specific metabolic pathways. Our results show that NMR spectroscopy is a suitable method to detect variance of the metabolome caused by subtle genetic differences. Thus, it has the potential to address genotype–phenotype associations in medaka, providing an additional level of phenotypic analysis.

Gender differences in Damp-Heat Syndrome: A review

Gender differences have important biological significance for medical research. In this study, a bias towards males was identified in animal experiments of Damp-Heat Syndrome in traditional Chinese medicine, as was first proposed by a data mining method. Combined with the correlation between Damp-Heat Syndrome in traditional Chinese medicine and Gender differences, it was considered that Gender-related factors have a significant influence on the development of Damp-Heat Syndrome in traditional Chinese medicine. However, most traditional Chinese medicine studies ignore the key significance of Gender-related factors. This study emphasises that the development of modern traditional Chinese medicine research needs to pay full attention to the biological significance of Gender-related factors and to apply this concept to the research on the Gender equivalence strategy in basic research and the practice of personalised medical diagnosis and clinical treatment.

Exposure to Prenatal Stress Is Associated With an Excitatory/Inhibitory Imbalance in Rat Prefrontal Cortex and Amygdala and an Increased Risk for Emotional Dysregulation

Epidemiological studies have shown that environmental insults and maternal stress during pregnancy increase the risk of several psychiatric disorders in the offspring. Converging lines of evidence from humans, as well as from rodent models, suggest that prenatal stress (PNS) interferes with fetal development, ultimately determining changes in brain maturation and function that may lead to the onset of neuropsychiatric disorders. From a molecular standpoint, transcriptional alterations are thought to play a major role in this context and may contribute to the behavioral phenotype by shifting the expression of genes related to excitatory and inhibitory (E/I) transmission balance. Nevertheless, the exact neurophysiological mechanisms underlying the enhanced vulnerability to psychopathology following PNS exposure are not well understood. In the present study, we used a model of maternal stress in rats to investigate the distal effects of PNS on the expression of genes related to glutamatergic and GABAergic neurotransmissions. We inspected two critical brain regions involved in emotion regulation, namely, the prefrontal cortex (PFC) and the amygdala (AMY), which we show to relate with the mild behavioral effects detected in adult rat offspring. We observed that PNS exposure promotes E/I imbalance in the PFC of adult males only, by dysregulating the expression of glutamatergic-related genes. Moreover, such an effect is accompanied by increased expression of the activity-dependent synaptic modulator gene Npas4 specifically in the PFC parvalbumin (PV)-positive interneurons, suggesting an altered regulation of synapse formation promoting higher PV-dependent inhibitory transmission and increased overall circuit inhibition in the PFC of males. In the AMY, PNS more evidently affects the transcription of GABAergic-related genes, shifting the balance toward inhibition. Collectively, our findings suggest that the E/I dysregulation of the PFC-to-AMY transmission may be a long-term signature of PNS and may contribute to increase the risk for mood disorder upon further stress.

Chronic pesticide exposure elicits a subtle carry-over effect on the metabolome of Aurelia coerulea ephyrae

Chemical pollutants, such as pesticides, often leach into aquatic environments and impact non-target organisms. Marine invertebrates have complex life cycles with multiple life-history stages. Exposure to pesticides during one life-history stage potentially influences subsequent stages; a process known as a carry-over effect. Here, we investigated carry-over effects on the jellyfish Aurelia coerulea. We exposed polyps to individual and combined concentrations of atrazine (2.5 μg/L) and chlorpyrifos (0.04 μg/L) for four weeks, after which they were induced to strobilate. The resultant ephyrae were then redistributed and exposed to either the same conditions as their parent-polyps or to filtered seawater to track potential carry-over effects. The percentage of deformities, ephyrae size, pulsation and respiration rates, as well as the metabolic profile of the ephyrae, were measured. We detected a subtle carry-over effect in two metabolites, acetoacetate and glycerophosphocholine, which are precursors of the neurotransmitter acetylcholine, important for energy metabolism and osmoregulation of the ephyrae. Although these carry-over effects were not reflected in the other response variables in the short-term, a persistent reduction of these two metabolites could have negative physiological consequences on A. coerulea jellyfish in the long-term. Our results highlight the importance of considering more than one life-history stage in ecotoxicology, and measuring a range of variables with different sensitivities to detect sub-lethal effects caused by anthropogenic stressors. Furthermore, since we identified few effects when using pesticides concentrations corresponding to Australian water quality guidelines, we suggest that future studies consider concentrations detected in the environment, which are higher than the water quality guidelines, to obtain a more realistic scenario by possible risk from pesticide exposure.