Matilde Capi

Xanthurenic Acid Activates mGlu2/3 Metabotropic Glutamate Receptors and is a Potential Trait Marker for Schizophrenia

The kynurenine pathway of tryptophan metabolism has been implicated in the pathophysiology of psychiatric disorders, including schizophrenia. We report here that the kynurenine metabolite, xanturenic acid (XA), interacts with, and activates mGlu2 and mGlu3 metabotropic glutamate receptors in heterologous expression systems. However, the molecular nature of this interaction is unknown, and our data cannot exclude that XA acts primarily on other targets, such as the vesicular glutamate transporter, in the CNS. Systemic administration of XA in mice produced antipsychotic-like effects in the MK-801-induced model of hyperactivity. This effect required the presence of mGlu2 receptors and was abrogated by the preferential mGlu2/3 receptor antagonist, LY341495. Because the mGlu2 receptor is a potential drug target in the treatment of schizophrenia, we decided to measure serum levels of XA and other kynurenine metabolites in patients affected by schizophrenia. Serum XA levels were largely reduced in a large cohort of patients affected by schizophrenia, and, in patients with first-episode schizophrenia, levels remained low after 12 months of antipsychotic medication. As opposed to other kynurenine metabolites, XA levels were also significantly reduced in first-degree relatives of patients affected by schizophrenia. We suggest that lowered serum XA levels might represent a novel trait marker for schizophrenia.

Altered intestinal permeability in patients with relapsing–remitting multiple sclerosis: A pilot study:

Background: Alterations of intestinal permeability (IP) may contribute to the pathophysiology of immune-mediated diseases. Objective: We investigated the possible association between IP changes and multiple sclerosis (MS). Methods: We studied 22 patients with relapsing–remitting multiple sclerosis (RRMS) and 18 age- and sex-matched healthy donors (HDs), including five twin pairs (one concordant, and four discordant for disease). Measurement of lactulose (L) and mannitol (M; two non-metabolized sugars) levels in urine samples, after an oral load, allowed to quantify gut dysfunction. Results: The proportion of participants with increased IP was significantly higher in patients than in HDs (16/22 (73%) versus 5/18 (28%); p = 0.001). Accordingly, the L/M urinary ratio showed significantly higher values in patients than in controls (p = 0.0284). Urinary mannitol concentration was significantly lower in patients than in controls (p = 0.022), suggesting a deficit of absorption from intestinal lumen. Such changes did not appear related to patients’ clinical–radiological features. Conclusion: The relatively high proportion of IP changes in RR-MS patients seems to confirm our work hypothesis and warrants more work to confirm the result on a larger sample, and to understand the implications for related immunological disturbances and intestinal microbiota alterations. Our finding may also have relevance for oral treatments, recently introduced in clinical practice.

The omics in migraine

The term omics consist of three main areas of molecular biology, such as genomics, proteomics and metabolomics. The omics synergism recognise migraine as an ideal study model, due to its multifactorial nature. In this review, the plainly research data featuring in this complex network are reported and analyzed, as single or multiple factor in pathophysiology of migraine. The future of migraine biomolecular research shall be focused on networking among these different and hierarchical disciplines. We have to look for its Ariadne’s tread, in order to see the whole painting of migraine molecular biology.

Sodium channel antagonists for the treatment of migraine.

Introduction: Migraine has a strong social impact, influencing both quality of life and work productivity. Therapeutic approach of migraine consists of a multimodal program of pharmacotherapy and behavioral therapy in order to reduce the risk of chronification. Indications for the use of preventive therapy are three or more attacks per month, significant disability, attack duration that is > 90 min. Areas covered: In this review, studies conducted on sodium channel antagonists for the prophylaxis of migraine are selected using the International Classification of Headache Disorders (ICHD)-I and -II diagnostic criteria for migraine and are open-label and placebo-controlled studies. Expert opinion: Several sodium channel antagonists, such as valproic acid, topiramate, lamotrigine, zonisamide, carbamazepine and oxcarbazepine, are widely used in migraine although without similar level of efficacy. Among these antiepileptic drugs, valproic acid and topiramate seem to be more effective in migraine, as reported in the majority of controlled studies. In spite of their high efficacy rate, important side effects should be always monitored, especially depression, cognitive functions, weight gain, sleepiness and dizziness. The usefulness of this class drug will be dramatically improved by using ongoing data on individual pharmacogenomics profile.

Choosing the safest acute therapy during chronic migraine prophylactic treatment: pharmacokinetic and pharmacodynamic considerations

ABSTRACT Introduction: Drugs used in the treatment of migraine have been reported to be highly associated with the occurrence of clinically significant drug-drug interactions (DDIs). Multiple drug therapy regimens are used for migraine treatment, particularly for chronic migraine. In fact, additional pharmacological agents are usually administered during an acute migraine attack in patients chronically treated with the prophylactic therapy. The variety of drugs available for migraine prophylactic and acute treatment, and consequently their pharmacological interactions, might complicate the choice of a safe combination therapy. Areas covered: This study discusses the prophylactic-acute DDIs from a pharmacokinetic and pharmacodynamic perspective, particularly interactions between antiepileptic drugs, tricyclic antidepressants, β-blockers, calcium channel blockers, triptans, nonsteroidal anti-inflammatory drugs and ergot derivatives. The available online tools have been used to evaluate the clinically significant DDIs. Expert opinion: The interactions between different drugs might be accurately predicted by the huge and detailed knowledge about the molecular pathways involved in pharmacodynamics and pharmacokinetics. Pharmacogenomic research has shed further light onto the mechanisms involved in the inter-individual variation in drug response and DDIs. Based on this knowledge, this paper will provide suggestions to improve the appropriateness of the drug choice in the prescription of preventative and acute migraine medications.

Lasmiditan for the treatment of migraine

ABSTRACT Introduction: Migraine is one of the most common diseases in the world, with high economical and subjective burden. Migraine acute therapy is nowadays based on specific and non-specific drugs but up to 40% of episodic migraineurs still have unmet treatment needs and over 35% do not benefit from triptans administration. Serotonin-1F receptors have been identified in trigeminal system and became an ideal target for anti-migraine drug development as potential trigeminal neural inhibitors. Lasmiditan, a novel serotonin1F receptor agonist, showed specific affinity in vitro for the receptor without any vasoconstrictive action and inhibited markers associated with electrical stimulation of trigeminal ganglion in migraine animal models. Areas covered: This article reviews both preclinical and clinical studies on lasmiditan as a potential acute therapy for migraine, as well as pharmacokinetic and pharmacodynamic features. It also summarizes safety and tolerability data gathered in the various human studies. Expert opinion: The absence of vasoconstrictive effects makes lasmiditan a promising novel migraine acute therapy. Although preclinical and Phase I and II studies established a significant efficacy, the limited knowledge about pharmacokinetics and metabolism, the high rate of non-serious central nervous system side effects and the lack of larger studies remain still a matter of concern that should be addressed in future studies.

Deciphering the task of N-acetyl aspartate in migraine

Evaluation of: de Tommaso M, Ceci E, Pica C et al. Serum levels of N-acetyl-aspartate in migraine and tension-type headache. J. Headache Pain 13(5), 389–394 (2012). Migraine is a common neurological disorder producing significant personal and societal burden. In the evaluated study, serum concentrations of N-acetyl aspartate (NAA), a biomarker of neuronal integrity, was found to be decreased in patients suffering from migraine with aura. These interesting results suggest a dual clinical readout. Since migraine-with-aura patients show an increased risk for stroke; the evaluation of serum levels of NAA is crucial in the control of the conventional risk factors. In addition, the therapeutic metabolite monitoring of NAA may be helpful in the assessment of the chronicization process.

Eletriptan in the management of acute migraine: an update on the evidence for efficacy, safety, and consistent response.

Migraine is a multifactorial, neurological and disabling disorder, also characterized by several autonomic symptoms. Triptans, selective serotonin 5-HT1B/1D agonists, are the first-line treatment option for moderate-to-severe headache attacks. In this paper, we review the recent data on eletriptan clinical efficacy, safety, and tolerability, and potential clinically relevant interactions with other drugs. Among triptans, eletriptan shows a consistent and significant clinical efficacy and a good tolerability profile in the treatment of migraine, especially for patients with cardiovascular risk factors without coronary artery disease. It shows the most favorable clinical response, together with sumatriptan injections, zolmitriptan and rizatriptan. Additionally, eletriptan shows the most complex pharmacokinetic/dynamic profile compared with the other triptans. It is metabolized primarily by the CYP3A4 hepatic enzyme and therefore the concomitant administration of CYP3A4-potent inhibitors should be carefully evaluated. A relatively low risk of serotonin syndrome is given by the co-administration with serotoninergic drugs. No clinically relevant interaction has been found with drugs used for migraine prophylactic treatment or other acute drugs, with the exception of ergot derivatives that should not be co-administered with eletriptan.

LC–MS/MS simultaneous analysis of allopregnanolone, epiallopregnanolone, pregnanolone, dehydroepiandrosterone and dehydroepiandrosterone 3-sulfate in human plasma

AIM Several neuropsychopharmacological properties have been attributed to the 3α-reduced pregnane steroids, allopregnanolone and pregnanolone, as well as to dehydroepiandrosterone sulfate because of their ability to modulate γ-aminobutyric acid (GABAA) receptors in the CNS. In order to understand better their role in several mechanisms in CNS, a new methodology is proposed to monitor these compounds in human plasma. Methodology & results: The analytes were first derivatized with 2-hydrazinopyridine and extracted from plasma using SPE. Then, the compounds were separated and detected by LC-MS/MS. A mobile phase of formic acid (0.1%) in water and methanol through a gradient of composition and a flow rate of 0.3 ml min-1 resulted in good separations of the analytes. Linear responses in wide range of concentrations and LOQs ranging from 10 (dehydroepiandrosterone 3-sulfate) to 40 pg ml-1 (dehydroepiandrosterone) were obtained in <9 min. The method proposed has been validated and then applied to monitor these neurosteroids in plasma samples from ten volunteers. CONCLUSION For the first time, a straightforward and reliable method for the chromatographic separation of allopregnanolone, epiallopregnanolone and pregnanolone, as well as of dehydroepiandrosterone and dehydroepiandrosterone 3-sulfate was carried out, with optimal accuracy, sensitivity and specificity.

Acute, transitional and long-term cluster headache treatment: pharmacokinetic issues

ABSTRACT Introduction: The cornerstones of cluster headache therapy are based on the tripod of acute, transitional and preventative treatments that respectively aim to the control of the bouts, the transitional suppression of the relapse and the prevention of the entire cluster period. Particularly in chronic cluster headache, where a long-term preventative therapy is necessary, multiple drug regimens increase the risk of drug-drug interactions leading to variability in the clinical efficacy and to potentially harmful adverse effects. Areas covered: We focused on how clinically significant pharmacokinetic drug-drug and food-drug interactions can be carefully managed both in cluster headache patients with a progressive frequency of bouts and in chronic cluster headache sufferers. In fact, in these cases a long-term preventive therapy is indicated, increasing the possibility of interactions both with other transitional and acute cluster headache medications and with other foods or xenobiotics. Expert opinion: Pharmacokinetic interactions for both preventive, transitional and acute drugs are significant with a number of xenobiotics and other medications. Therefore, the pharmacokinetic issues knowledge is advisable for a safe and effective cluster headache management.