Epigenetic mechanisms are involved in the pathophysiology of depressive disorders and are unique potential targets for therapeutic intervention. The acetylating agent L-acetylcarnitine (LAC), a welltolerated drug, behaves as an antidepressant by the epigenetic regulation of type 2 metabotropic glutamate (mGlu2) receptors. It caused a rapid and long-lasting antidepressant effect in Flinders Sensitive Line rats and in mice exposed to chronic unpredictable stress, which, respectively, model genetic and environmentally induced depression. In both models, LAC increased levels of acetylated H3K27 bound to the Grm2 promoter and also increased acetylation of NF-ĸB-p65 subunit, thereby enhancing the transcription of Grm2 gene encoding for the mGlu2 receptor in hippocampus and prefrontal cortex. Importantly, LAC reduced the immobility time in the forced swim test and increased sucrose preference as early as 3 d of treatment, whereas 14 d of treatment were needed for the antidepressant effect of chlorimipramine. Moreover, there was no tolerance to the action of LAC, and the antidepressant effect was still seen 2 wk after drug withdrawal. Conversely, NF-ĸB inhibition prevented the increase in mGlu2 expression induced by LAC, whereas the use of a histone deacetylase inhibitor supported the epigenetic control of mGlu2 expression. Finally, LAC had no effect on mGlu2 knockout mice exposed to chronic unpredictable stress, and a single injection of the mGlu2/3 receptor antagonist LY341495 partially blocked LAC action. The rapid and long-lasting antidepressant action of LAC strongly suggests a unique approach to examine the epigenetic hypothesis of depressive disorders in humans, paving the way for more efficient antidepressants with faster onset of action.BDNF | histone acetylation | MDD | glutamatergic neurotransmission | chromatin

BackgroundThe efficacy and safety of OnabotulinumtoxinA (BOTOX®) in adults with chronic migraine (CM) were demonstrated in the PREEMPT program. However, the dosage used in this study was flexible from 155 U to 195 U at the physician’s discretion. Therefore, the objective of this prospective study was to compare the efficacy and safety of OnabotulinumtoxinA 195 U vs. 155 U for the treatment of CM and medication overuse headache (MOH) during a 2-year period.MethodsWe prospectively evaluated the mean reduction in headache days, migraine days, acute pain medication intake days and Headache Impact Test (HIT)-6 score in 172 patients injected with OnabotulinumtoxinA 195 U. Successively, we compared the efficacy measures with data of 155 patients injected with OnabotulinumtoxinA 155 U and followed up for 2 years. All patients were affected by CM and MOH, and failed one or more previous detoxification and preventative therapies.ResultsBoth OnabotulinumtoxinA 195 U and 155 U reduced significantly the number of headache and migraine days, acute pain medication intake days and HIT-6 score, when compared with the baseline measures. Nevertheless, OnabotulinumtoxinA 195 U proved to be superior of 155 U in all efficacy measures since the first injection and for all the 2 years of treatment, with the exception of the reduction in pain medication intake days that resulted significantly larger with 195 U only after the 4th injection. The safety and tolerability of the two doses were similar and treatment related adverse events were transient and mild-moderate.ConclusionsThis study represents the largest and longest post-marketing studies of doses comparison with OnabotulinumtoxinA in a real-life clinical setting.Here, we demonstrate the superior efficacy of OnabotulinumtoxinA 195 U compared to 155 U in CM patients with MOH during a 2-year treatment period with similar safety and tolerability profile.Electronic supplementary materialThe online version of this article (doi:10.1186/s10194-016-0591-3) contains supplementary material, which is available to authorized users.

BackgroundImmune checkpoint inhibitors have revolutionized the treatment paradigm of highly lethal malignancies like advanced non-small cell lung cancer (NSCLC), demonstrating long-term tumour control and extended patient survival. Unfortunately, only 25–30% of patients experience a durable benefit, while the vast majority demonstrate primary or acquired resistance. Recently, indoleamine 2,3-dioxygenase (IDO) activity has been proposed as a possible mechanism of resistance to anti-PD-1 treatment leading to an immunosuppressive microenvironment.MethodsPre-treatment serum concentrations of tryptophan (trp) and kynurenine (kyn) were measured by high-performance liquid chromatography tandem mass spectrometry in NSCLC patients treated with second-line nivolumab. The IDO activity was expressed with kyn/trp ratio. The associations between kyn/trp ratio and early progression, performance status (PS), age, sex, brain metastases, pleural effusion, progression free survival (PFS) and overall survival (OS) were analyzed using Spearman test and Mann–Whitney test.ResultsTwenty-six NSCLC patients were included in our study; 14 of them (54%) presented early progression (< 3 months) to nivolumab treatment. The median value of kyn/trp ratio was 0.06 µg/ml and the median value of quinolinic acid was 68.45 ng/ml. A significant correlation between early progression and higher kyn/trp ratio and quinolinic acid concentration was observed (p = 0.017 and p = 0.005, respectively). Patients presenting lower values of kyn/trp ratio and quinolinic acid levels showed longer PFS (median PFS not reached versus 3 months; HR: 0.3; p = 0.018) and OS (median OS not reached vs 3 months; HR: 0.18; p = 0.0005).ConclusionIDO activity, expressed as kyn/trp ratio, is associated with response to immunotherapy; in particular, higher kyn/trp ratio could predict resistance to anti-PD-1 treatment. These preliminary results suggest the possibility of using anti-PD-1 plus IDO inhibitor in those patients with high level of kyn/trp ratio.

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BackgroundActivation of glutamate (Glu) receptors plays a key role in the pathophysiology of migraine. Both NMDA and metabotropic Glu receptors are activated or inhibited by metabolites of the kynurenine pathway, such as kynureninic acid (KYNA), quinolinic acid (QUINA), and xanthurenic acid (XA). In spite of the extensive research carried out on KYNA and other kynurenine metabolites in experimental models of migraine, no studies have ever been carried out in humans. Here, we measured all metabolites of the kynurenine pathway in the serum of patients affected by chronic migraine (CM) and age- and gender-matched healthy controls.MethodsWe assessed serum levels of tryptophan (Trp), L-kynurenine (KYN), KYNA, anthranilic acid (ANA), 3-hydroxyanthranilic acid (3-HANA), 3-hydroxykynirenine (3-HK), XA, QUINA, and 5-hydroxyindolacetic acid (5-HIAA) in 119 patients affected by CM (ICHD-3beta criteria) and 84 age-matched healthy subjects.Patients with psychiatric co-morbidities, systemic inflammatory, endocrine or neurological disorders, and mental retardation were excluded. Serum levels of all metabolites were assayed using liquid chromatography/tandem mass spectrometry (LC-MS/MS).ResultsLC-MS/MS analysis of kynurenine metabolites showed significant reductions in the levels of KYN (−32 %), KYNA (−25 %), 3-HK (−49 %), 3-HANA (−63 %), 5-HIAA (−36 %) and QUINA (−80 %) in the serum of the CM patients, as compared to healthy controls. Conversely, levels of Trp, ANA and XA were significantly increased in CM patients (+5 %, +339 % and +28 %, respectively).ConclusionsThese findings suggest that in migraine KYN is unidirectionally metabolized into ANA at expenses of KYNA and 3-HK. The reduction in the levels of KYNA, which behaves as a competitive antagonist of the glycine site of NMDA receptors, is consistent with the hypothesis that NMDA receptors are overactive in migraine. The increase in XA, a putative activator of Glu2 receptors, may represent a compensatory event aimed at reinforcing endogenous analgesic mechanisms. The large increase in the levels of ANA encourages research aimed at establishing whether ANA has any role in the regulation of nociceptive transmission.

The efficacy and safety of OnabotulinumtoxinA 155-195 U (BOTOX®) in adults with chronic migraine (CM) were demonstrated in both the Phase III Research Evaluating Migraine Prophylaxis Therapy (PREEMPT) studies. However, data about its long-term efficacy and safety in clinical settings are scanty. Therefore, the objective of this study is to evaluate OnabotulinumtoxinA 155 U treatment in patients affected with CM and co-morbid medication overuse headache (MOH) over 2-year analysis. We prospectively evaluated 155 CM and MOH affected patients started on OnabotulinumtoxinA 155U (PREEMPT injection paradigm) between October 2010 and November 2011 and followed-up for 2 years. All patients failed to positively respond to previous multiple preventive therapies that were withdrawn before starting OnabotulinumtoxinA. Headache days, migraine days, acute pain medication intake days and Headache Impact Test (HIT)-6 score were used as efficacy measures, whereas safety was evaluated with side effects occurrence during the treatment phase. Baseline data were collected from patients headache diary referred to the previous month, and patients were evaluated every 3 months at the time of each injection. OnabotulinumtoxinA 155U significantly reduced the number of headache and migraine days (p < 0.001), acute pain medication intake days (p < 0.001) and HIT-6 score (p < 0.001) when compared with the baseline data. The reduction was significant after the first injection (p < 0.001), and gradually increased during the 2 years of treatment. Treatment related adverse events were transient and mild-moderate (e.g. headache, injection-site pain, eyelid ptosis, musculoskeletal weakness). This prospective 2-years analysis of efficacy and safety of long-term treatment with OnabotulinumtoxinA 155 U in patients affected with CM and MOH confirms the efficacy data from previous Randomized Clinical Trials for CM prophylaxis. Moreover, here we demonstrate that OnabotulinumtoxinA can be safely used for the long-term treatment of MOH comorbidity in CM.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-015-1636-9) contains supplementary material, which is available to authorized users.

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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.