Cluster headache and kynurenines

The glutamatergic neurotransmission has important role in the pathomechanism of primary headache disorders. The kynurenine metabolites derived from catabolism of tryptophan (Trp) have significant involvement not only in glutamatergic processes, but also in the neuroinflammation, the oxidative stress and the mitochondrial dysfunctions. Previously we identified a depressed peripheral Trp metabolism in interictal period of episodic migraineurs, which prompted us to examine this pathway in patients with episodic cluster headache (CH) as well. Our aims were to compare the concentrations of compounds both in headache-free and attack periods, and to find correlations between Trp metabolism and the clinical features of CH. Levels of 11 molecules were determined in peripheral blood plasma of healthy controls (n = 22) and interbout/ictal periods of CH patients (n = 24) by neurochemical measurements.Significantly decreased L-kynurenine (KYN, p < 0.01), while increased quinolinic acid (QUINA, p < 0.005) plasma concentrations were detected in the interbout period of CH patients compared to healthy subjects. The levels of KYN are further reduced during the ictal period compared to the controls (p < 0.006). There was a moderate, negative correlation between disease duration and interbout QUINA levels (p < 0.048, R = - 0.459); and between the total number of CH attacks experienced during the lifetime of patients and the interbout KYN concentrations (p < 0.024, R = - 0.516). Linear regression models revealed negative associations between age and levels of Trp, kynurenic acid, 3-hdyroxyanthranilic acid and QUINA in healthy control subjects, as well as between age and ictal level of anthranilic acid.Our results refer to a specifically altered Trp metabolism in CH patients. The onset of metabolic imbalance can be attributed to the interbout period, where the decreased KYN level is unable to perform its protective functions, while the concentration of QUINA, as a toxic compound, increases. These processes can trigger CH attacks, which may be associated with glutamate excess induced neurotoxicity, neuroinflammation and oxidative stress. Further studies are needed to elucidate the exact functions of these molecular alterations that can contribute to identify new, potential biomarkers in the therapy of CH

Development and validation of high performance liquid chromatography method for the measurements of biogenic amines

Many important biogenic amines (dopamine, noradrenaline and serotonin) are produced from amino acids by enzyme-catalysed processes and play a prominent role in neuronal functions and therefore, they serve as pharmacological target for the treatment of neurological disorders, such as Alzheimer’s disease or Parkinson’s disease. The aim of the current study was to optimize a high-performance liquid chromatography method that allows selective separation of eight biogenic amines and some of their metabolites (levodopa, 3,4-dihydroxyphenylacetic acid, noradrenaline, 5-hydroxyindoleacetic acid, homovanillic acid, dopamine, serotonin and 3-methoxythyramine) using 3 internal standards with electrochemical detection. During the development of our method, we optimized the amount of ion pairing component, pH and the amount of organic phase. Several selective methods were tested, but the most effective one was used for validation process for mouse and rat brain regions, including the striatum, cortex and hippocampus. During validation, the limit of detection, the limit of quantification, recovery, intraday and interday precisions were determined for the eight analytes. The ranges of recovery were between 87 and 120%, the intraday and interday precision were < 10% in all cases. The limit of detection and quantification ranged around 2 and 10 ng/ml, respectively. The developed and optimized method ensures the measurement of the aforementioned biogenic amines from mouse and rat brain regions

E-vitamin mérésre alkalmas nagyhatékonyságú folyadékkromatográfiás módszerek fejlesztése és validálása = Development and validation of high performance liquid chromatography methods for vitamin E measurements

Tocopherols, also known as the ingredients of fat-soluble vitamin E compounds play an important role in antioxidant mechanisms. Their deficiency of tocopherols, mainly that of αtocopherol, can cause several neurological disorders, such as ataxia, myopathy, retinopathy, peripheral neuropathy. The aim of this study was to validate and establish methods applicable for the detection of α-tocopherol from murine serum and certain brain regions. In the present study we report 3 different reversed-phase HPLC methods using a single C18 column in isocratic system. The detection was carried out with 3 different detectors. For the detection of murine serum samples, a diode-array detector (DAD) was applied, whereas for murine brain samples electrochemical (ECD) and fluorescence detectors (FLD) were utilized and a detailed validation process was carried out. The ranges of precision and recovery were the following during the validation processes: 0.61-3.57% and 66.19-105.91%, respectively. The application of these methods provide a valuable tool for the determination of αtocopherol from murine serum and brain samples

Triptofán és bizonyos metabolitjainak koncentrációjának meghatározása Creutzfeldt-Jakob betegeknél = The assessment of concentrations of certain tryptophan metabolites in Creutzfeldt-Jakob disease

The kynurenine (KYN) pathway (KP), also known as the route where more than 95% of the tryptophan (TRP) is metabolized, in its steps of catabolism forms different metabolites which contribute to the neuroprotective–neurodegenerative changes in central nervous system. For this reason, TRP metabolism is extensively studied in neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease, Huntington’s disease), where the neurologically active metabolite concentration changes are followed. Kynurenic acid (KYNA), which is an endogenous N-methyl-D-aspartate receptor (NMDAR) antagonist, is considered to be a neuroprotective agent. In the present study TRP, KYN and KYNA were determined from human serum and cerebrospinal fluid (CSF) of patients with Creutzfeldt-Jakob disease (CJD) and age- and gender-matched controls, using high performance liquid chromatography (HPLC) applying UV and fluorescent detectors. The developed method was optimized and validated according to the International Congress Harmonization Guidelines. The precision and recovery values ranged between 1.60-4.36%, 81.61-101.09%, respectively. There were no differences between the groups with regard all the measured metabolites. The application of the developed validated method enabled the simultaneous determination of certain metabolites of the KP of TRP metabolism, but no evident alterations were found in patients with CJD

The Tryptophan-Kynurenine Metabolic System Is Suppressed in Cuprizone-Induced Model of Demyelination Simulating Progressive Multiple Sclerosis

Progressive multiple sclerosis (MS) is a chronic disease with a unique pattern, which is histologically classified into the subpial type 3 lesions in the autopsy. The lesion is also homologous to that of cuprizone (CPZ) toxin-induced animal models of demyelination. Aberration of the tryptophan (TRP)-kynurenine (KYN) metabolic system has been observed in patients with MS; nevertheless, the KYN metabolite profile of progressive MS remains inconclusive. In this study, C57Bl/6J male mice were treated with 0.2% CPZ toxin for 5 weeks and then underwent 4 weeks of recovery. We measured the levels of serotonin, TRP, and KYN metabolites in the plasma and the brain samples of mice at weeks 1, 3, and 5 of demyelination, and at weeks 7 and 9 of remyelination periods by ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) after body weight measurement and immunohistochemical analysis to confirm the development of demyelination. The UHPLC-MS/MS measurements demonstrated a significant reduction of kynurenic acid, 3-hydoxykynurenine (3-HK), and xanthurenic acid in the plasma and a significant reduction of 3-HK, and anthranilic acid in the brain samples at week 5. Here, we show the profile of KYN metabolites in the CPZ-induced mouse model of demyelination. Thus, the KYN metabolite profile potentially serves as a biomarker of progressive MS and thus opens a new path toward planning personalized treatment, which is frequently obscured with immunologic components in MS deterioration

Activation of Transient Receptor Potential Vanilloid 3 Regulates Inflammatory Actions of Human Epidermal Keratinocytes

K