Efficacy of Fenfluramine and Norfenfluramine Enantiomers and Various Antiepileptic Drugs in a Zebrafish Model of Dravet Syndrome.

Dravet syndrome (DS) is a rare genetic encephalopathy that is characterized by severe seizures and highly resistant to commonly used antiepileptic drugs (AEDs). In 2020, FDA has approved fenfluramine (FFA) for treatment of seizures associated with DS. However, the clinically used FFA is a racemic mixture (i.e. (±)-FFA), that is substantially metabolized to norfenfluramine (norFFA), and it is presently not known whether the efficacy of FFA is due to a single enantiomer of FFA, or to both, and whether the norFFA enantiomers also contribute significantly. In this study, the antiepileptic activity of enantiomers of FFA (i.e. (+)-FFA and (-)-FFA) and norFFA (i.e. (+)-norFFA and (-)-norFFA) was explored using the zebrafish scn1Lab-/- mutant model of DS. To validate the experimental conditions used, we assessed the activity of various AEDs typically used in the fight against DS, including combination therapy. Overall, our results are highly consistent with the treatment algorithm proposed by the updated current practice in the clinical management of DS. Our results show that (+)-FFA, (-)-FFA and (+)-norFFA displayed significant antiepileptic effects in the preclinical model, and thus can be considered as compounds actively contributing to the clinical efficacy of FFA. In case of (-)-norFFA, the results were less conclusive. We also investigated the uptake kinetics of the enantiomers of FFA and norFFA in larval zebrafish heads. The data show that the total uptake of each compound increased in a time-dependent fashion. A somewhat similar uptake was observed for the (+)-norFFA and (-)-norFFA, implying that the levo/dextrotation of the structure did not dramatically affect the uptake. Significantly, when comparing (+)-FFA with the less lipophilic (+)-norFFA, the data clearly show that the nor-metabolite of FFA is taken up less than the parent compound.

Local immune response to food antigens drives meal-induced abdominal pain.

Up to 20% of people worldwide develop gastrointestinal symptoms following a meal1, leading to decreased quality of life, substantial morbidity and high medical costs. Although the interest of both the scientific and lay communities in this issue has increased markedly in recent years, with the worldwide introduction of gluten-free and other diets, the underlying mechanisms of food-induced abdominal complaints remain largely unknown. Here we show that a bacterial infection and bacterial toxins can trigger an immune response that leads to the production of dietary-antigen-specific IgE antibodies in mice, which are limited to the intestine. Following subsequent oral ingestion of the respective dietary antigen, an IgE- and mast-cell-dependent mechanism induced increased visceral pain. This aberrant pain signalling resulted from histamine receptor H1-mediated sensitization of visceral afferents. Moreover, injection of food antigens (gluten, wheat, soy and milk) into the rectosigmoid mucosa of patients with irritable bowel syndrome induced local oedema and mast cell activation. Our results identify and characterize a peripheral mechanism that underlies food-induced abdominal pain, thereby creating new possibilities for the treatment of irritable bowel syndrome and related abdominal pain disorders.

Development of a HILIC-MS/MS method for the quantification of histamine and its main metabolites in human urine samples.

An LC-MS/MS method was developed enabling the separation and quantification of histamine and its main metabolites (imidazole acetaldehyde, imidazole acetic acid, methyl imidazole acetic acid, methyl histamine, acetyl histamine) in urine samples. A fast separation was achieved in 10 min on two HILIC columns connected in series by adopting a linear gradient followed by an isocratic hold. The sample preparation consisted of a simple dilution step wherein 10 µL of urine was diluted with acetonitrile (ACN) to a final volume comprising 95% ACN. For methyl imidazole acetic acid, an additional dilution step was incorporated due to its high natural levels. Hereafter, the samples were stored at -20 °C and centrifuged prior to injection. Matrix matched calibrators were unavailable due to the endogenous occurrence of the compounds of interest. The occurrence of matrix effects and the lack of labeled internal standards prompted the use of the standard addition method as a viable alternative to solvent calibration. The validation of the method entailed matrix effects, accuracy and precision and was performed in compliance with the recent guidelines on endogenous compounds issued by the International Conference of Harmonization (ICH). The method was then adopted for the quantification of histamine and its metabolites in human urine samples collected from healthy volunteers and patients suffering from gastrointestinal discomfort.

Patient-centered care coordination, education and counseling of patients treated with oral anticancer drugs: An importance-performance analysis.

PURPOSE: To analyse the importance and performance of key elements in patient-centered care coordination, education and counseling of patients treated with oral anticancer drugs. METHOD: In four Belgian non-academic hospitals, the importance and performance of a set of 82 key elements was cross-sectionally evaluated by primary and secondary healthcare professionals and by patients. These key elements were divided in 6 themes: coordination of care, style and content of patient contacts, medication counseling at treatment initiation, follow-up of treatment, psychosocial support, and involvement of family and friends. Participants were asked to indicate for each key element if it was implemented in the current care process for patients on oral anticancer drugs ('yes', 'no', 'I don't know') and if they considered it important that the component was implemented or would be in the future ('yes' or 'no'). Three levels of performance were defined, based on the number of participants who had answered 'yes' or 'no': 'systematically performed' (≥90% of participants), 'not systematically performed' (≥75% and <90%) and 'not performed' (<75%). Importance-rates were based on the number of 'yes' or 'no'. RESULTS: In total, 85 participants evaluated the key elements. More than half of key elements, 13/82 (15.9%) and 35/82 (42.6%) respectively, were considered as 'not' or 'not systematically performed'. The majority of these elements concerned coordination of care, medication counseling at treatment initiation and follow-up of treatment. Especially key elements on involving primary care and on discussing adherence had low performance rates. Nearly all key elements were assigned an importance score of ≥90%. CONCLUSIONS: Performance of key elements of patient-centered care coordination, education and counseling of patients treated with oral anticancer drugs proved moderate. Our findings suggest that strategies are needed to prioritize and operationalize key elements to coordinate transmural care and to provide effective education and counseling.