Histamine and histamine intolerance

Total histamine degrading capacity: Correlation to stool histamine and its usefulness in supporting the diagnosis of histamine intolerance

The relatively new test (European Patent granted 2022) for determining the total histamine degradation capacity [Totale Histamin Abbau Kapazität/Total Histamine Degrading Capacity] THAK®/THDC of a serum sample has been compared in various settings with the individual clinical history and the levels of histamine in stool. The measurement of THAK can be carried out regardless of the current status of the patient (independent of any acute symptoms), therefore THAK test is a useful and very reliable instrument for supporting the diagnosing histamine intolerance. As soon as the THAK falls below a threshold value the patient is most likely to suffer from HIT, even if the intensity of the symptoms is low. Low THAK values correspond with a significant increase of histamine in stool. Results were evaluated according to both age and gender, no difference between the sexes were found. However, there is a noticeable dependency on age, although this is not diagnostically relevant. THAK® is a registered trademark of Frost Diagnostika.

Potential of fermented foods and their metabolites in improving gut microbiota function and lowering gastrointestinal inflammation

Foods prepared using microbial conversion of major and minor food components, which are otherwise known as fermented foods continue to impact human health. The live microorganisms and transformed metabolites can also have a deep influence on the gut microbiota, the multifaceted population of microorganisms dwelling inside the gut play a key role in wellbeing of an individual. The probiotic strains delivered through the consumption of fermented food and other bioactive components such as polyphenolic metabolites, bioactive peptides, short-chain fatty acids and others including those produced via gut microbiota mediated transformations have been proposed to balance the gut microbiota diversity and activity, and also to regulate the inflammation in the gut. However, little is known about such effects and only a handful of fermented foods have been explored to date. We herein review the recent knowledge on the dysbiotic gut microbiota linking to major gut inflammatory diseases. Also, evidences that fermented food consumption modulates the gut microbiota, and its impact on the gut inflammation and inflammatory diseases have been discussed. © 2024 Society of Chemical Industry.

Effectiveness of histamine receptor antagonists in the treatment of histamine-driven clinical symptoms: do we have a histamine or, better, an anti-histamine problem?

Why are up to 50% of patients with chronic urticaria resistant to antihistamines? Why do many patients with indolent systemic mastocytosis suffer severe symptoms despite treatment with four times the approved antihistamine doses? Do millions of patients with atopic diseases and related disorders have a histamine or, better, an antihistamine problem? If one carefully analyzes human clinical studies with exogenous histamine challenge and endogenous mast cell activation with prophylactic antihistamine pretreatment, the assumed efficacy of antihistamines rapidly fades. Local tissue free drug concentrations of many antihistamines are <100 nM compared with 10-1000 µM possible extracellular local histamine concentrations after mast cell activation. Is the pharmaceutical industry aware of this problem?

Diamine oxidase acts as a novel risk factor in abnormal inflammation via mediating "cytosolic ROS-autophagy-IFN-γ" axis in NK cells

AIMS

Diamine oxidase (DAO), a well-established biomarker for intestinal damage, histamine intolerance or tumorigenesis, has rarely been reported in immune regulation. This study aimed to identify DAO as a critical enhancer of abnormal inflammation by promoting interferon-gamma (IFN-γ) production from natural killer (NK) cells.

MAIN METHODS

Clinical bioinformatics analyzed aoc1 (DAO-coding gene) expression in PBMCs from patients with inflammatory diseases. Murine models (LPS-induced systemic inflammation, sepsis, DSS-induced colitis) using DAO-/- mice, alongside DAO-/- NK92 cells and DAO inhibitor DIZE, were employed for phenotypic validation. Cellular profiling, bone marrow chimeras, reciprocal transplantation, RNA-sequence, non-targeted metabolomics, and flow cytometry were utilized to dissect DAO's mechanisms in NK cells.

KEY FINDINGS

DAO deficiency protected mice from inflammatory pathology by suppressing IFN-γ production. NK cells were identified as the primary target cells during the process, with DAO acting intracellularly to promote IFN-γ via a reactive oxygen species (ROS)-autophagy axis. DAO-derived ROS, distinct from mitochondrial or NOX2 sources, enhanced autophagic flux during NK activation, enabling IFN-γ biosynthesis. DAO did not affect NK homeostasis, including maturation, proliferation, or receptor expressions.

SIGNIFICANCE

DAO is a novel risk factor in inflammatory diseases, driving IFN-γ production through ROS-autophagy signaling in NK cells. Targeting DAO may offer therapeutic strategies for conditions involving dysregulated IFN-γ responses, including sepsis, colitis, and autoimmune disorders.

Cutaneous mastocytosis: diagnostic challenges and dietary influences

Cutaneous mastocytosis (CM) is a rare condition characterized by abnormal mast cell proliferation in the skin. We present the case of a 65-year-old man with recurrent urticaria-like rashes persisting for more than eight years. Despite multiple misdiagnoses as insect bites, examination and biopsy revealed mast cell infiltration. The patient's unique lifestyle, particularly his frequent seafood consumption, adds an intriguing dimension to the case. Treatment with systemic antihistamines and corticosteroids provided symptomatic relief, but long-term follow-up showed the persistence of clinical lesions, indicating that the treatment did not adequately address the underlying cause of the disease. A notable improvement in disease control was observed when the patient's diet was adjusted, suggesting a potential link between food and cutaneous mastocytosis. To our knowledge, this is the first documented case of maculopapular cutaneous mastocytosis in Syria.

Diet, nutraceuticals, and lifestyle interventions for the treatment and management of irritable bowel syndrome

Irritable bowel syndrome (IBS) is the most common gastrointestinal (GI) disorder of the gut-brain interaction and causes significant GI distress. The etiology of IBS is multifactorial, with food intolerances being a frequent contributing factor to IBS symptoms. Diet and lifestyle interventions are key components in comprehensive IBS care. In this review, we examine the current evidence-based dietary approaches for treating IBS. The low-FODMAP diet has the most robust data for improving overall symptom burden. In conjunction with guidance from a registered dietitian, certain patients may benefit from targeted dietary elimination of specific carbohydrates such as lactose or fructose or gluten. Among the nutraceuticals used to treat IBS, peppermint oil has sufficient evidence and appropriate safety data to recommend adjunctive use to reduce IBS symptoms. Although prebiotic and probiotic food sources may be beneficial to the microbiome, there is not enough evidence to support the routine use of prebiotic or probiotic supplements. Given the complexity of IBS, a holistic approach in which clinicians address a patients' diet, culture, sleep hygiene, exercise habits, and mental health may improve patients' overall quality of life.

Recombinant production of a diamine oxidase in Komagataella phaffii and in vitro degradation of histamine in simulated intestinal fluid

Diamine oxidase (DAO-1) from Yarrowia lipolytica was recombinantly produced in Komagataella phaffii in fed-batch bioreactor cultivations using the constitutive GAP and methanol-inducible AOX1 promoters. Utilizing an exponential glucose feed, a maximum DAO-1 activity of 43 ± 7 µkat/Lculture was achieved after 37 h of cultivation using the GAP promoter. When the AOX1 promoter was used, a maximum DAO-1 activity of 230 ± 13 µkat/Lculture was achieved after 90 h of cultivation with a stepwise increase in the methanol feed. Thus, approximately 15- (GAP promoter) and 82-fold (AOX1 promoter) higher DAO-1 activities were obtained in K. phaffii compared to homologous recombinant production in Y. lipolytica. The DAO-1 produced in K. phaffii has been partially purified and was formulated as a sucrose-based tablet containing 4500 nkat DAO-1 activity. The DAO-1 tablet was tested for histamine degradation in a simulated intestinal fluid in the presence of food components, and approximately 90 % of the histamine applied initially (75 mg) was degraded in 90 minutes. This is the first time that a DAO-1 tablet has been able to break down such large amounts of histamine under simulated intestinal fluid conditions, which could help people with histamine intolerance in the future.

Food Intolerances and Food Allergies: Novel Aspects in a Changing World

Despite the rapid progress that has considerably affected most fields of medicine in recent years, many gray areas still exist in our understanding of allergies/hypersensitivities and intolerances to foods [...].

Clinical Trial: A Mediterranean Low-FODMAP Diet Alleviates Symptoms of Non-Constipation IBS-Randomized Controlled Study and Volatomics Analysis

Background: Approximately 20% of patients with irritable bowel syndrome (IBS) link symptoms to food intake; a low-FODMAP diet is effective in managing these symptoms. Aims: To evaluate the effectiveness of the Mediterranean version of the low-FODMAP Diet (MED-LFD) compared to NICE guidelines for IBS and to assess changes in stool volatile compound levels. Methods: 108 patients with Rome IV IBS without constipation were randomized into the MED-LFD or NICE group. Primary endpoints included changes in symptom severity and responder rate (reduction of >50 IBS-SSS points) after intervention and at 6 months. Secondary endpoints assessed quality of life, symptom burden, adequate relief, anxiety/depression levels, and adherence. Volatile compound levels were measured using Gas Chromatography/Mass Spectrometry. Results: At both time points, the MED-LFD group showed a significantly greater improvement in symptom severity (159 ± 80 vs. 253 ± 94 and 168 ± 117 vs. 245 ± 98), responder rates (84.6% vs. 60.8% and 79.1% vs. 52.3%), and adherence (75% vs. 41% and 45% vs. 7%). Similar results were observed for all secondary endpoints, with no serious adverse events reported. The MED-LFD intervention was the strongest independent predictor of being a responder at the first (OR = 6.66; 95%CI = 1.46, 30.4) and second follow-up (OR = 4.85; 95%CI = 1.31, 17.96). Short and branched-chain fatty acids were significantly reduced at both follow-ups. Conclusions: The MED-LFD is superior to NICE recommendations in managing non-constipated IBS symptoms and quality of life. It remains to be proven that reduced volatile compound levels might be an objective marker of response to dietary interventions. ClinicalTrials.gov ID: NCT03997708.

COVID-19 mRNA-1273 vaccination induced mast cell activation with strongly elevated Th2 cytokines in a systemic mastocytosis patient

OBJECTIVE AND DESIGN

SARS-CoV-2 vaccines are recommended for mastocytosis patients. We describe clinical symptoms, chemokine, cytokine, metabolomic and lipidomic derangements in a systemic mastocytosis patient following mRNA-1273 booster vaccination.

METHODS

Twenty-eight chemokines and cytokines, 41 amino acids and 16 lipid classes were quantified with state-of-the-art methods.

RESULTS

Mast cell activation (MCA) symptoms started 24 h after the mRNA-1273 booster vaccination with significant metabolic, lipidomic and cytokine derangements. Histamine concentrations peaked at life-threatening 18 ng/ml concomitant with high tryptase. Peak plasma IL-1Ra, IL-5, IL-6, IL-10, IL-11, CXCL10 and GM-CSF concentrations were elevated 54-, 4.9-, 85-, 54-, 6.1-, 19- and 6.4-fold respectively. Tocilizumab, an IL-6 receptor antagonist, was administered 6 h after admission, because of the highly elevated IL-6 concentrations. More than one year later IL-6 was highly elevated during another MCA attack likely caused by a PCR-proven SARS-CoV-2 infection and tocilizumab was again used. Clinical symptoms improved during the following 12 h similar to the vaccine booster MCA attack.

CONCLUSIONS

A mRNA-1273 first booster vaccination likely caused a delayed severe MCA attack with highly elevated Th2-biased cytokines with metabolic and lipidomic derangements. Administration of an IL-6 receptor blocker during both MCA attacks might have shortened the duration of clinical symptoms.

The tree of life of copper-containing amine oxidases

Copper-containing amine oxidases (CuAOs) catalyze the terminal oxidation of polyamines (PAs), producing ammonium, an aminoaldehyde, and hydrogen peroxide (H2O2). Plant CuAOs are induced by stress-related hormones such as methyl-jasmonate (MeJA), abscisic acid (ABA), and salicylic acid (SA). Mammalian copper-containing amine oxidases (CAOs), encoded by four genes (AOC1-4) that catalyze the oxidation of primary amines to aldehydes, regulate various biological processes and are linked to diseases like inflammatory conditions and histamine intolerance. To understand the evolutionary history and functional divergence of CuAOs, we conducted phylogenetic and expression analyses of CuAOs in plants and animals. In this study, the copper amine oxidase (CuAO) genes were identified by HMMER and BLASTP, and verified by CDD/HMM/SMART. Multiple sequence alignment was performed using Muscle5, and the phylogenetic tree was constructed by IQ-TREE2. The syntenic relationship was analyzed by MCScanX and CIRCOS. Meanwhile, the expression data of Arabidopsis thaliana and human and other species were integrated for analysis. Here, 950 and 264 CuAO orthologues were identified in 188 plant and 79 animal genomes. Phylogenetic analyses indicate that CuAO originated in the common ancestor before the divergence of plants and animals. The copy numbers of CuAOs vary significantly across plant species, whereas they remain relatively stable in animal species, generally maintaining 3-4 copies per species. During the evolutionary process, plant CuAOs formed two clades (I and II), while animal CuAOs formed three clades (CAO-like, AOC1, AOC2-4). Interestingly, plant clade I CuAOs lacks the active site motif T/S-X1-X2-N-Y-D. The further differentiation of plant clade II CuAOs is related to the preference for X1 and X2 active sites. CAO-like and AOC1 are monophyletic branches. Mammalian AOC2-4 is separated from non-mammalian AOC2-4, and the differentiation of mammalian AOC3 and AOC4 occurs in a species-specific manner. Our study provides a comprehensive understanding of the evolutionary trajectory of the CuAO gene family in plants and animals at the genome-wide level. These findings lay a crucial foundation for future research to conduct in-depth functional characterization.

Food Hypersensitivity: Distinguishing Allergy from Intolerance, Main Characteristics, and Symptoms-A Narrative Review

Background/Objectives: Food hypersensitivity remains an understudied and overlooked subject globally. It is characterized by adverse reactions to dietary substances, potentially triggered by various mechanisms. Food allergy, a subset of food hypersensitivity, denotes an immune response to food proteins categorized into immunoglobulin IgE-mediated or non-IgE-mediated reactions. Conversely, food intolerance, another facet of food hypersensitivity, refers to non-immunological reactions, in which the human body cannot properly digest certain foods or components, leading to gastrointestinal discomfort and other non-immune-related symptoms. The main objective of this study was to determine and differentiate the differences, characteristics, and types of food hypersensitivity. Methods: This study involved a comprehensive review of key research from 1990 onward, including review articles, prospective studies, nested case-control studies, and meta-analyses. Results: Recognizing these differences is essential for healthcare professionals to ensure accurate diagnosis, effective management, and improved patient outcomes, while also aiding dietitians in providing optimal nutritional and dietary guidance. Conclusions: there are big differences between the main characteristics, such as symptoms, complications, and treatments between allergies, and food intolerances. Commonly reported trigger foods include cow milk, gluten, eggs, nuts, and seafood.

Amino acid-based, sustainable organic nanozyme and integrated sensing platform for histamine detection

Inorganic nanozymes hold promise for biomolecule sensing but face challenges like complex fabrication, toxicity, and low sustainability, limiting their use. To overcome these, a sustainable organic nanozyme (OA nanozyme) was created using amino acids and a biocompatible polymer for effective histamine detection. The OA nanozyme exhibits peroxidase-like activity and was fabricated through a single chelation/polymer entanglement method, enabling rapid production (within 3 h) with uniform morphology (≤100 nm diameter) and a negative surface charge at neutral pH. It shows decent kinetic performance (Km = 0.009 mM for H2O2) and biocompatibility, making it suitable for biological applications. The OA nanozyme achieved high sensitivity for histamine detection (LOD: 21.37 pgmL-1) with excellent selectivity and specificity against related molecules. The system's ability to detect histamine in real food samples (e.g., spinach) was also confirmed. These findings indicate that the OA nanozyme holds significant potential for broader applications in food safety and quality assurance.

Biogenic Amine Metabolism and Its Genetic Variations in Autism Spectrum Disorder: A Comprehensive Overview

Autism spectrum disorder (ASD) is a genetically heterogeneous syndrome characterized by repetitive, restricted, and stereotyped behaviors, along with persistent difficulties with social interaction and communication. Despite its increasing prevalence globally, the underlying pathogenic mechanisms of this complex neurodevelopmental disorder remain poorly understood. Therefore, the identification of reliable biomarkers could play a crucial role in enabling early screening and more precise classification of ASD subtypes, offering valuable insights into its physiopathology and aiding the customization of treatment or early interventions. Biogenic amines, including serotonin, histamine, dopamine, epinephrine, norepinephrine, and polyamines, are a class of organic compounds mainly produced by the decarboxylation of amino acids. A substantial portion of the genetic variation observed in ASD has been linked to genes that are either directly or indirectly involved in the metabolism of biogenic amines. Their potential involvement in ASD has become an area of growing interest due to their pleiotropic activities in the central nervous system, where they act as both neurotransmitters and neuromodulators or hormones. This review examines the role of biogenic amines in ASD, with a particular focus on genetic alterations in the enzymes responsible for their synthesis and degradation.

The Effect of Linarin on Relevant Inflammatory Markers in Ovalbumin-Induced Asthma Rat Models

Objective

In the current work, we investigated and assessed the ability of the bioactive flavone linarin (LIN) to prevent asthma in the ovalbumin (OVA)-induced rat model.

Methods

The experimental rats' body weight and relative lung weight were measured after each treatment. Indices of oxidative stress in lung tissue and erythrocytes were assessed. Analyses were conducted on hematological assays, measurement of histamine release in BALF fluid, and inflammatory markers found in blood and BALF, including IL-4, IL-13, TNF-α, IFN-γ, and IgE levels. For histological examination, tissue samples were collected.

Results

Administration of LIN significantly increased the rats' body weight; however, their relative lung weight decreased. According to our findings, LIN significantly raised SOD, GSH, and CAT levels while suppressing MDA content. The administration of LIN resulted in a considerable reduction in IgE levels, cytokines, and hematological assay influx in the corresponding samples. Histological assessment showed that LIN treatment significantly maintained the anatomy of the lungs and decreased the infiltration of inflammatory cells.

Conclusion

The regulation of oxidative stress and the avoidance of pulmonary airway inflammation are two proposed methods by which LIN may reduce asthma symptoms.

Novel insights on the biology and immunologic effects of histamine: A road map for allergists and mast cell biologists

Histamine (C5H9N3, molecular weight 111.15 g/mol) is a well-studied endogenous biogenic amine composed of an imidazole ring attached to an ethylamine side chain. It has a limited half-life of a few minutes within tissues and in circulation. Several cell types including mast cells (MCs), basophils, platelets, histaminergic neurons, and enterochromaffin cells produce varying amounts of histamine using histidine decarboxylase. However, only MCs and basophils have complex mechanisms to pack and store histamine in granules along with other mediators using serglycin and its carried glycosaminoglycan side chains. Relatively low granule pH (∼5.5) supports the binding of stored histamine to heparin, whereas exposure to neutral pH after degranulation weakens the binding and histamine becomes liberated. Histamine exerts multifaceted regulatory biofunctions by engaging its 4 types of heptahelical G protein-coupled receptors (H1R-H4R), which have different expression profiles and functions. MCs express H1R, H2R, and H4R, which gives them a dual role in histamine biology as producers and responsive target cells. Histamine plays a role in a variety of physiologic and pathologic processes such as cell proliferation, differentiation, hematopoiesis, vascular permeability, embryogenesis, tissue regeneration, and wound healing. The emergence of histamine receptor-deficient mouse models and the development of multiple histamine receptor agonists and antagonists have helped researchers better understand these physiologic and pathogenic functions of histamine. We review the biology of histamine with a focus on immunologic aspects and the role of histamine in allergy and MC biology.

Bioprospecting Indigenous Oenococcus oeni Strains from Chinese Wine Regions: Multivariate Screening for Stress Tolerance and Aromatic Competence

Malolactic fermentation (MLF), an essential enological process for wine deacidification and aroma development, is predominantly mediated by Oenococcus oeni (O. oeni). This investigation characterized 170 indigenous O. oeni isolates from two principal Chinese viticultural regions (Yinchuan, Ningxia, and Changli, Hebei) through polyphasic analysis. Forty-nine strains demonstrating genetic potential for efficient malate metabolism and biosafety compliance (absence of ethyl carbamate and biogenic amines genes) were subjected to adaptive laboratory evolution under enologically relevant stress conditions. Comparative evaluation with the superior indigenous strain SD-2a revealed eight stress-adapted isolates exhibiting superior MLF kinetics, completing L-malic acid degradation in Marselan wine. Solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) profiling identified three isolates' (3-31, 9-10, and 9-50) significant enhancement of key fermentation aromas in experimental fermentations. These oenologically adapted indigenous strains demonstrate promising potential as regional-specific starter cultures, providing a scientific foundation for developing terroir-expressive winemaking practices and optimizing microbial resources in China's wine industry.

A Microbial Endocrinology-Designed Discovery Platform to Identify Histamine-Degrading Probiotics: Proof of Concept in Poultry

Histamine is a biogenic amine found across the phylogenetic spectrum, from plants to fish to animals. In farm animal production, the host's production of histamine within the intestinal tract serves as a neurotransmitter, facilitating communication from the gut to the brain. Histamine functions additionally as a "bridging" chemical between the immune and nervous systems as it facilitates nervous system modulation of host immune response, thereby playing a critical role in host defense within the gut. Increased histamine levels within the gut, whether originating from food-borne sources or produced in situ, can lead to immune dysregulation and consequent physiological harm. As such, control of histamine within the gut can improve overall gut health across a broad range of species. In the present study, we utilized a Microbial Endocrinology-based approach as a platform technology to enable the discovery of unique histamine-degrading bacteria within the gut microbiota. Broiler chickens were fed, or not, a low or high histamine-supplemented diet from one day of age to up to 42 days in order to encourage the increased abundance of putative histamine-degrading bacteria. Intestinal contents were employed in a discovery protocol that involved repeated isolation rounds utilizing a histamine-supplemented minimal medium. We herein report the discovery that the genus Brevibacterium are capable of up to 100% degradation of histamine in vitro. Feeding experiments utilizing one of the identified Brevibacterium spp., a B. sediminis isolate, demonstrated that it reduced the amount of histamine in the gut of broilers fed a histamine-containing diet and enabled an improvement in growth as compared to non-B. sediminis-supplemented animals. As such, this study demonstrates the usefulness of a Microbial Endocrinology-based approach for the discovery of bacteria that may serve as potential probiotic candidates for the control of neurochemical-mediated interactions within the host, thereby improving host health.

Histamine-modulated wettability switching in G-protein-coupled receptor inspired nanochannel for potential drug screening and biosensing

Histamine receptor, one typical G-protein-coupled receptor (GPCR), can be activated by histamine and form the most important drug targets involved in allergy and reflux diseases. Here, we report an artificial model to mimic the wettability-induced activation of natural GPCRs via histamine-modulated enhancement of wettability in a bionic nanochannel. The artificial receptor is constructed by introducing key recognition factors in nature, L-lysine modified fluorescein isothiocyanate (L-lysine-FITC), into a conical nanochannel. The conductance of the L-lysine-FITC-modified nanochannel increases with the histamine-induced wettability enhancement due to the various interactions between histamine and L-lysine-FITC molecules including hydrogen bonding and π-π interactions, as well as the proton transfer reaction. This study represents a crucial step towards the design of artificial GPCRs with wettability-induced activation and provides an opportunity to construct artificial models of GPCRs in a non-lipid environment. The developed artificial receptor has great potential application in medicinal chemistry, biosensors, and healthcare systems.

Construction of flexible paper-based sensor for label-free recognition of histamine in cow meat samples by conductive nano-silver ink: a new platform for the analysis of biogenic amines towards early diagnosis of meat spoil

Biogenic amines are organic nitrogen compounds that play key roles in various biological processes and are produced through amino acid decarboxylation. Among these, histamine stands out as a toxic biogenic amine with the potential to cause serious health issues when present at elevated levels in food, highlighting the importance of effective detection methods. However, current histamine detection approaches are often hindered by high costs, lengthy analysis times, and intricate procedures. This research introduces a novel, label-free method for detecting histamine in meat samples using highly conductive nano-silver inks to develop miniaturized sensors based on paper microdevice technology. The proposed paper-based electrochemical sensors offer significant advantages, including affordability, reproducibility, and environmental sustainability. A newly designed paper-based microsensor was developed for label-free histamine detection employing conductive nano-silver ink via a pen-on-paper technique. The fabrication process of the microsensor was thoroughly characterized through methods like field emission scanning electron microscope (FE-SEM), Energy Dispersive X-ray (EDAX), and Atomic Force microscopy (AFM). Key findings indicate that the microsensor successfully detects histamine concentrations across a broad dynamic range of 10 to 1000 nM, with a lower limit of quantification set at 10 nM. Validation of the sensor's performance was conducted using electrochemical tools such as cyclic voltammetry and square wave voltammetry, confirming its efficacy for real-time histamine monitoring in food products and biological environments. Additionally, the study underscores the sensor's excellent selectivity, long-term stability, and lightning-fast responsiveness, positioning it as a highly promising tool to enhance food safety and quality assurance.

Nanostructured WS2@Chitosan-Modified Screen-Printed Carbon Electrodes for Efficient Amperometric Detection of Histamine

Histamine, a pivotal chemical within certain cells of the human body, is responsible for eliciting various allergic symptoms, such as sneezing and a runny nose. In cases of allergies, where the immune system misidentifies typically harmless substances, such as certain foods or dust, as harmful, an efficient histamine sensor becomes imperative. This research introduces a novel sensing platform by employing a material comprising hydrothermally synthesized WS2 nanosheets and using this with a chitosan (CS) biopolymer on a screen-printed carbon electrode (SPE). Integrating WS2 and CS components on the SPE via drop-casting synergistically enhances conductivity and various sensor properties. This novel hybrid material combines organic CS and inorganic WS2 components applied for nonenzymatic histamine detection via differential pulse voltammetry. This study also included crystallite size determination and surface morphology assessment through characterization of the synthesized WS2 nanosheets. On the surface of the SPE, WS2 and CS were drop-casted. It is recommended that histamine be electrochemically measured on modified WS2/CS/SPE electrodes. Histamine measurements were conducted within a linear coverage of 1-100 μM, with a limit of detection of 0.0844 μM and sensitivity of 1.44 × 10-4 mA/μM cm2. The developed sensor exhibited notable levels of sensitivity, selectivity, stability, and repeatability, along with an extended linear range. The sensing technique was consequently employed to detect the histamine levels in packed food items like fermented food samples (cheese, tomato sauce, tomato ketchup, and soy sauce) at room temperature (25 °C). The findings recommend the utilization of electrochemical sensing on modified WS2/CS/SPE electrodes for accurate histamine detection.

The Prevalence of Single Nucleotide Polymorphisms of the AOC1 Gene Associated with Diamine Oxidase (DAO) Enzyme Deficiency in Healthy Newborns: A Prospective Population-Based Cohort Study

Background/Objectives: The prevalence of the diamine oxidase (DAO) enzyme deficiency of a genetic origin has not been previously assessed. A prospective population-based study was conducted in a sample of 200 healthy newborns aimed to determine the prevalence of DAO enzyme deficiency caused by single nucleotide polymorphism (SNP) variants of the AOC1 gene. Methods: Genotyping was performed in oral mucosa samples collected around 2 days after birth. The four more frequent SNPs, c.47C>T (rs10156191), c.995C>T (rs1049742), c.1990C>G (rs10449793), and c.691G>T (rs2052129), were analyzed. Results: DAO deficiency was present in 132 newborns, with a prevalence of 66% (95% confidence interval [CI] 59-73%). The rs10449793 variant showed a prevalence of 46%, followed by rs10156191 with a prevalence of 42.5%, and rs2052129 with a prevalence of 39.5%. The variant rs1049742 showed the lowest prevalence (9.5%). The frequency of one, two, three, or four SNPs was 23%, 23.5%, 10.5%, and 9%, respectively. In all fours SNP variants, heterozygous carriers were more frequent than homozygous carriers (19% homozygosity). Differences in the prevalence of DAO deficiency between males (68%, 66/96) and females (63.4%, 66/104) were not found (p = 0.885). The prevalence in Caucasian newborns was 66.5% (123/185), as compared with 60% (9/15) in Latin Americans (p = 0.821). Conclusions: This study carried out in healthy newborns indicates that there is a high prevalence (66%) of DAO deficiency of a genetic origin in the general population.

Study Protocol for a Prospective, Unicentric, Double-Blind, Randomized, and Placebo-Controlled Trial on the Efficacy of a Low-Histamine Diet and DAO Enzyme Supplementation in Patients with Histamine Intolerance

BACKGROUND/OBJECTIVES

Histamine intolerance is primarily caused by a deficiency in the diamine oxidase (DAO) enzyme at the intestinal level. The reduced histamine degradation in the gut leads to its accumulation in plasma, thereby causing multiple clinical manifestations, such as urticaria, diarrhea, headache, dyspnea, or tachycardia, among others. The dietary management of this food intolerance consists of the follow-up of a low-histamine diet, often combined with DAO supplementation. To date, around twenty studies have investigated the effectiveness of these dietary strategies in reducing the frequency and/or intensity of symptoms, with promising results. However, the limitations of these studies (small patient cohort, lack of control group, and short dietary intervention periods) highlight the need for more ambitiously designed research. Therefore, the main objective of this prospective, unicentric, double-blind, randomized, and placebo-controlled trial is to evaluate the efficacy of a low-histamine diet and/or DAO supplementation over a three-month period in improving symptoms of histamine intolerance. Additionally, the impacts of these dietary strategies on the intestinal microbiota composition, urinary profile of histamine metabolites, serum DAO activity, and plasma histamine levels will be assessed throughout the intervention.

METHODS

The trial will enroll 400 patients who will be randomly assigned to one of two groups: the intervention group, which will follow a low-histamine diet, or the control group, which will maintain their habitual dietary habits. Within each of these groups, participants will be further divided into four subgroups to receive either exogenous DAO enzyme supplementation (from porcine or plant sources, with the latter administered at two different dosages) or a placebo. Therefore, a total of eight distinct intervention groups will be considered. The comparison of these groups will allow the evaluation of the individual effects of the low-histamine diet or DAO enzyme supplementation, as well as their possible synergistic effect.

RESULTS

The results of this study should help to improve dietary recommendations for histamine-intolerant patients and ultimately enhance their quality of life.

Gene Variant Related Neurological and Molecular Biomarkers Predict Psychosis Progression, with Potential for Monitoring and Prevention

The (MTHFR) C677T gene polymorphism is associated with neurological disorders and schizophrenia. Patients diagnosed with schizophrenia and schizoaffective disorder and controls (n 134) had data collected for risk factors, molecular and neuro-sensory variables, symptoms, and functional outcomes. Promising gene variant-related predictive biomarkers were identified for diagnosis by Receiver Operating Characteristics and for illness duration by linear regression. These were then analyzed using Spearman's correlation in relation to the duration of illness. Significant correlations were ranked by strength and plotted on graphs for each MTHFR C677T variant. Homozygous MTHFR 677 TT carriers displayed a mid-illness switch to depression, with suicidality and a late-phase shift from lower to higher methylation, with activated psychosis symptoms. MTHFR 677 CC variant carriers displayed significant premorbid correlates for family history, developmental disorder, learning disorder, and head injury. These findings align with those of low methylation, oxidative stress, multiple neuro-sensory processing deficits, and disability outcomes. Heterozygous MTHFR 677 CT carriers displayed multiple shifts in mood and methylation with multiple adverse outcomes. The graphically presented ranked biomarker correlates for illness duration allow a perspective of psychosis development across gene variants, with the potential for phase of illness monitoring and new therapeutic insights to prevent or delay psychosis and its adverse outcomes.

Fibre & fermented foods: differential effects on the microbiota-gut-brain axis

The ability to manipulate brain function through the communication between the microorganisms in the gastrointestinal tract and the brain along the gut-brain axis has emerged as a potential option to improve cognitive and emotional health. Dietary composition and patterns have demonstrated a robust capacity to modulate the microbiota-gut-brain axis. With their potential to possess pre-, pro-, post-, and synbiotic properties, dietary fibre and fermented foods stand out as potent shapers of the gut microbiota and subsequent signalling to the brain. Despite this potential, few studies have directly examined the mechanisms that might explain the beneficial action of dietary fibre and fermented foods on the microbiota-gut-brain axis, thus limiting insight and treatments for brain dysfunction. Herein, we evaluate the differential effects of dietary fibre and fermented foods from whole food sources on cognitive and emotional functioning. Potential mediating effects of dietary fibre and fermented foods on brain health via the microbiota-gut-brain axis are described. Although more multimodal research that combines psychological assessments and biological sampling to compare each food type is needed, the evidence accumulated to date suggests that dietary fibre, fermented foods, and/or their combination within a psychobiotic diet can be a cost-effective and convenient approach to improve cognitive and emotional functioning across the lifespan.

Characterization of Human Breast Milk-Derived Limosilactobacillus reuteri MBHC 10138 with Respect to Purine Degradation, Anti-Biofilm, and Anti-Lipid Accumulation Activities

Background: Human breast milk is a valuable source of potential probiotic candidates. The bacteria isolated from human breast milk play an important role in the development of the infant gut microbiota, exhibiting diverse biological functions. Methods: In this study, Limosilactobacillus reuteri MBHC 10138 isolated from breast milk was characterized in terms of its probiotic safety characteristics and potential efficacy in hyperuricemia, obesity, lipid liver, and dental caries, conditions which Korean consumers seek to manage using probiotics. Results: Strain MBHC 10138 demonstrated a lack of D-lactate and biogenic amine production as well as a lack of bile salt deconjugation and hemolytic activity. It also exhibited susceptibility to common antibiotics, tolerance to simulated oral-gastric-intestinal conditions, and superior biological activity compared to three L. reuteri reference strains, including KACC 11452 and MJ-1, isolated from feces, and a commercial strain isolated from human breast milk. Notably, L. reuteri MBHC 10138 showed high capabilities in assimilating guanosine (69.48%), inosine (81.92%), and adenosine (95.8%), strongly inhibited 92.74% of biofilm formation by Streptococcus mutans, and reduced lipid accumulation by 32% in HepG2 cells. Conclusions: These findings suggest that strain MBHC 10138, isolated from human breast milk, has potential to be developed as a probiotic for managing hyperuricemia, obesity, and dental caries after appropriate in vivo studies.

Monoamine oxidase and neurodegeneration: Mechanisms, inhibitors and natural compounds for therapeutic intervention

Mammalian flavoenzyme Monoamine oxidase (MAO) resides on the outer mitochondrial membrane (OMM) and it is involved in the metabolism of different monoamine neurotransmitters in brain. During MAO mediated oxidative deamination of relevant substrates, H2O2 is released as a catalytic by-product, thus serving as a major source of reactive oxygen species (ROS). Under normal conditions, MAO mediated ROS is reported to propel the functioning of mitochondrial electron transport chain and phasic dopamine release. However, due to its localization onto mitochondria, sudden elevation in its enzymatic activity could directly impact the form and function of the organelle. For instance, in the case of Parkinson's disease (PD) patients who are on l-dopa therapy, the enzyme could be a concurrent source of extensive ROS production in the presence of uncontrolled substrate (dopamine) availability, thus further impacting the health of surviving neurons. It is worth mentioning that the expression of the enzyme in different brain compartments increases with age. Moreover, the involvement of MAO in the progression of neurological disorders such as PD, Alzheimer's disease and depression has been extensively studied in recent times. Although the usage of available synthetic MAO inhibitors has been instrumental in managing these conditions, the associated complications have raised significant concerns lately. Natural products have served as a major source of lead molecules in modern-day drug discovery; however, there is still no FDA-approved MAO inhibitor which is derived from natural sources. In this review, we have provided a comprehensive overview of MAO and how the enzyme system is involved in the pathogenesis of different age-associated neuropathologic conditions. We further discussed the applications and drawbacks of the long-term usage of presently available synthetic MAO inhibitors. Additionally, we have highlighted the prospect and worth of natural product derived molecules in addressing MAO associated complications.

Methylated tirilazad may mitigate oligofructose-induced laminitis in horses

Laminitis is a serious health condition that can cause severe pain and lameness in horses. Due to lack of understanding of laminitis, treatments often fail to achieve the desired results. In recent years, we have begun to recognize that laminitis may involve a complex interaction between local and systemic inflammation. Dysbiosis of the gut microbiota has been linked in the development of systemic inflammation, and our previous findings suggest that the development of laminitis is closely linked to the production of harmful metabolites of the gut microbiota. In addition, it was found that localized lesions in the hoof, especially lamellar injuries, are the most direct cause of laminitis. Matrix metalloproteinases have been found to be strongly associated with the development of laminitis. Recent discovery has found that methylated tirilazad has a role in repairing laminar tissue in vitro. However, its efficacy in horses never has been studied. Therefore, we aimed to investigate the efficacy of methylated tirilazad (product name: PTP-102) in the prevention/treatment of oligofructose-induced laminitis. The results showed that oligofructose successfully induced laminitis in horses, resulting in detreated clinical signs. Blood indices (including inflammation-related indices and other related indices) were significantly increased. Observations of dissection and staining showed significant bleeding, swelling, and damage to hoof tissue. Analysis of the gut microbiota showed a significant decrease in abundance and diversity, and a significant increase in the relative abundance of specific bacteria. Following methylated tirilazad intervention, there were a significant improvement in clinical signs, blood markers and lamellar tissue damage. Additionally, methylated tirilazad positively influenced the gut microbiota structure by reducing the relative abundance of genera closely associated with the development of equine laminitis. This suggests that some of the therapeutic mechanism of methylated tirilazad may be linked to its effects on the gut microbiota. Notably, methylated tirilazad had better effect in the treatment group than the prophylactic group, indicating the post-diagnosis utility of methylated tirilazad for laminitis management.

Association of histamine-N-methyl transferase gene polymorphisms with carnosine content in red-brown Korean native chickens

OBJECTIVE

Carnosine and anserine affect the meat flavor. The contents of carnosine and anserine in meat are affected by genetic and environmental factors. This study aimed to discover the single-nucleotide polymorphisms (SNPs) in the histamine-N-methyl transferase (HNMT) and histamine-N-methyl transferase-like (HNMT-like) genes and to associate them with the content of carnosine and anserine in Korean native chickenred brown line (KNC-R).

METHODS

This study used a total of 384 birds (males, n = 192; females, n = 192) aged 10 weeks old, for genotyping HNMT and HNMT-like genes. One synonymous SNP (rs29009298C/T) of the HNMT gene was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods whereas four missense SNPs (rs734406537G/A; rs736514667A/G; rs15881680G/A and rs316765035T/C) of the HNMT gene, and one missense SNP rs737657949A/C of the HNMT-like gene were genotyped by PCR allele competitive extension (PACE) genotyping technology. Two-way analysis of variance of the R program was used to associate HNMT genotypes with the contents of carnosine and anserine in KNC-R chickens.

RESULTS

There were significant associations (p<0.05) between the genotypes of the synonymous SNP:rs29009298C/T, missense SNP rs736514667A/G of the HNMT gene and the content of carnosine in KNC-Rs. This study also reported the sex effect on the carnosine content, where females had more content of carnosine compared to that of male KNC-R.

CONCLUSION

Two SNPs (synonymous: rs735769522C/T) and missense: rs736514667A/G) in the HNMT gene might be used as genetic markers in the selection and breeding of chickens with better taste and high-flavored meat.

The Role of hCG and Histamine in Emesis Gravidarum and Use of a Chewing Gum Containing Vitamin C as a Treatment Option: A Double-Blinded, Randomized, Controlled Trial

Background: Nausea and vomiting in pregnancy (NVP), or emesis gravidarum, is a frequent complication of early gestation with unclear causes, suspected to involve genetic, hormonal, and gastrointestinal factors. Our study investigated the association of human chorionic gonadotropin (hCG), histamine, diamine oxidase (DAO), thyroxine and pyridoxine and the severity of NVP symptoms and assessed the efficacy of a vitamin C-containing chewing gum as a potential NVP treatment. Methods: In this prospective, double-blinded, randomized, controlled trial, 111 participants were assigned to receive vitamin C-containing chewing gum, placebo gum, or no treatment at two follow-ups during early pregnancy. Maternal serum levels of hCG, histamine, DAO, thyroxine, and pyridoxine were measured and correlated with NVP severity using the Pregnancy-Unique Quantification of Emesis and Nausea (PUQE-24) score. Results: Elevated maternal hCG levels were significantly associated with an increased PUQE-24 score (p < 0.001), while histamine levels showed no significant correlation (p = 0.68). Maternal DAO levels negatively correlated with NVP symptoms (p < 0.001) and elevated thyroxine (p < 0.001) and pyridoxine levels (p < 0.001) were associated with increased PUQE-24 scores. The vitamin C-containing chewing gum did not demonstrate efficacy in alleviating NVP symptoms compared to placebo gum or no treatment during the first (p = 0.62) and second follow-up visits (p = 0.87). Conclusions: Our study underscores the complexity of factors contributing to NVP, highlighting the significant roles of hCG and DAO, while histamine levels appear unrelated. Maternal thyroxine and pyridoxine levels also significantly correlate with NVP symptoms. Vitamin C-containing chewing gum was not effective as a treatment for NVP. Further large-scale studies are needed to better understand these interactions and develop targeted treatments in the future.

Efficacy of Carbonate Buffer Mixture in Preventing Hoof Lamella Injury Associated with Subacute Ruminal Acidosis in Dairy Goats

Subacute ruminal acidosis (SARA) is a prevalent metabolic disorder in highly productive dairy cows that results in serious issues, including hoof lamellar injuries. This study aimed to investigate the efficacy of a carbonate buffer mixture (CBM) in preventing hoof lamella injury in dairy goats, a species also susceptible to SARA due to similar feeding practices over a 17-week period. Twenty-four healthy dairy goats were randomly assigned to three groups: control, SARA, and CBM groups. The control group received a standardized diet, whereas the SARA and CBM groups were subjected to a high-grain feeding regimen to induce SARA. The CBM group received a daily supplement of 10 g CBM mixed with their diet. Clinical assessments, including body temperature, rumen pH, inflammatory markers, matrix metalloproteinases (MMPs), and hoof lamellar injuries, were monitored throughout the study. The results showed that the CBM group maintained a more stable rumen pH and had lower levels of inflammatory markers than the SARA group did. The incidence of hoof lamellar injury was slightly lower in the CBM group. These findings suggest that long-term CBM supplementation may mitigate SARA-associated hoof lamella injury in dairy goats by regulating the rumen environment, fostering the growth of healthy bacterial communities, and by reducing the production of harmful metabolites. The use of CBM as a dietary supplement may have significant implications in improving the health, welfare, and productivity of dairy animals.

Exploring factors influencing the levels of biogenic amines in wine and microbiological strategies for controlling their occurrence in winemaking

Fermented beverages, including wine, can accumulate high concentrations of biogenic amines (BAs), which can pose potential health risks. BAs are produced by various yeasts and lactic acid bacteria (LAB) during winemaking. LAB are the main contributors to the formation of histamine and tyramine, the most toxic and food safety relevant biogenic amines. Numerous factors, ranging from agricultural and oenological practices to sanitation conditions, can contribute to the formation of BAs in wines. Moreover, organic and biodynamic wines impose limitations on the use of common food additives employed to control the proliferation of native and spoilage microorganisms during vinification and storage. To mitigate histamine production, commercial starter cultures incapable of synthesising histamine have been effectively utilised to reduce wine histamine content. Alternative fermentative microorganisms are currently under investigation to enhance the safety, quality, and typicity of wines, including indigenous LAB, non-Saccharomyces yeasts, and BAs degrading strains. Furthermore, exploration of extracts from BAs-degrading microorganisms and their purified enzymes has been undertaken to reduce BAs levels in wines. This review highlights microbial contributors to BAs in wines, factors affecting their growth and BA production, and alternative microorganisms that can degrade or avoid BAs. The aim is to lessen reliance on additives, providing consumers with safer wine choices.

Measurement of diamine oxidase (DAO) during low-histamine or ordinary diet in patients with histamine intolerance

BACKGROUND/OBJECTIVES

Quantification of diamine oxidase (DAO) concentrations in serum has been proposed as an adjunctive diagnostic modality for the evaluation of histamine intolerance (HIT). Limited empirical data exist concerning the influence of dietary patterns on DAO levels.

SUBJECTS/METHODS

In the context of a prospective study employing a crossover design, 18 individuals diagnosed with HIT were randomized to initiate either a low histamine diet (LHD) or a conventional mixed diet (MXD). Serum DAO concentrations were measured at the commencement of the study and following each dietary phase. A control group underwent analogous DAO assessments without imposition of dietary constraints.

RESULTS

During the time when a diet restricted in histamine was implemented, noticeable differences in changes in DAO levels did not become apparent when compared to the changes observed during the mixed (MXD) phase. Specifically, among the group, 10 of the 18 patients exhibited elevated DAO values subsequent to the LHD regimen, while the remaining eight displayed either reduced or unchanging DAO levels. The prevalence of elevated DAO levels in the LHD group did not differ significantly from that observed in the control group during the MXD phase. Additionally, during the LHD phase, patients reported a significant reduction in gastrointestinal and cutaneous symptoms.

CONCLUSIONS

This prospective investigation underscores the enduring utility of a histamine-restricted diet, coupled with structured dietary reintroduction, as an efficacious diagnostic approach for individuals presenting with suspected food-related histamine hypersensitivity. Notably, the measurement of DAO levels appears to furnish only a limited capacity to discern dietary-induced fluctuations. Notwithstanding, the dynamics of DAO alteration do not appear to exhibit a discernible association with specific dietary patterns, a finding consistent across both patient and control groups.

The role of histamine and its receptors in breast cancer: from pathology to therapeutic targets

Breast cancer is the most common malignancy in women, and despite the development of new treatment methods and the decreasing mortality rate in recent years, one of the clinical problems in breast cancer treatment is chronic inflammation in the tumor microenvironment. Histamine, an inflammatory mediator, is produced by tumor cells and can induce chronic inflammation and the growth of some tumors by recruiting inflammatory cells. It can also affect tumor physiopathology, antitumor treatment efficiency, and patient survival. Antihistamines, as histamine receptor antagonists, play a role in modulating the effects of these receptors in tumor cells and can affect some treatment methods for breast cancer therapy; in this review, we investigate the role of histamine, its receptors, and antihistamines in breast cancer pathology and treatment methods.

Salivary Histamine Levels in Patients with Oral Lichen Planus Lesions

Background and Objectives: An oral lichen planus (OLP) chronic lesion refers to a group of oral potentially malignant disorders (OPMDs) that still lack a proper understanding from the point of view of relevant biomarkers for diagnostics and prognosis. The aim of the study was to assess the salivary histamine levels in patients with oral lichen planus lesions. Materials and Methods: The study included a group of 76 patients with oral lichen planus. General diseases and medication taken, smoking habits, severity of pain assessed using a visual analogue scale (VAS), oral hygiene status, and duration of OLP were evaluated. ELISA diagnostics for histamines in saliva levels were assessed. Results: The histamine levels in the OLP group were higher (0.468) in comparison with the control group (0.056), without a statistically significant value p = 0.090 (Mann-Whitney U Test). The median age of 76 OLP patients was 63 years (min 22.0-max. 81), with the biological sex being 80.3% females and 15 19.7% males. The average duration of OLP lesion presence was 29.4 months (SD 37.1) and the median value was 14.5 months. The median of the VAS was 3.0. OLP assessment in accordance with the Malhotra methodology showed the highest frequency-30.3% for only two of the point areas involved and 17.1% for three points. Clinical assessment of the different OLP grades, severity, and oral site involvement and the VAS in correlation with histamine salivary levels showed a lack of statistical significance in the investigated population. Conclusions: Undertaking further research could provide further possibilities for searching for general factors in OLP development.

Microbial contribution to 14 biogenic amines accumulation in refrigerated raw and deep-fried hairtails (Trichiurus lepturus)

Biogenic amines (BAs) produced by microbial decarboxylation of amino acids are crucial toxic nitrogenous compounds in fish. An optimized ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method with simple pretreatment was established to detect 14 BAs in both raw (control check, CK) and deep-fried (DF) hairtails. This method exhibited a good linear relationship with average recoveries of 73.3-120.0 % and relative standard deviations of 2.5-10.0 %, respectively. The total BAs in CK and DF hairtails decreased sharply to 338.2 and 25.3 mg/kg on the 9th day, respectively. Four BAs, including cadaverine (CAD), histamine (HIS), tyramine (TYR), and putrescine (PUT) accounted for 92.5-99.9 % of total BAs were selected as the dominant BAs. Bacterial analysis showed that the abundance of DF was relatively low. Further correlation analysis proved that Vibrio had a significant (p < 0.05) positive correlation with total BAs and could be the main BA-producing bacterium in DF hairtail. This work provides new evidence of the accumulation of BAs in refrigerated hairtail.

Postprandial symptoms in disorders of gut-brain interaction and their potential as a treatment target

Postprandial, or meal-related, symptoms, such as abdominal pain, early satiation, fullness or bloating, are often reported by patients with disorders of gut-brain interaction, including functional dyspepsia (FD) or irritable bowel syndrome (IBS). We propose that postprandial symptoms arise via a distinct pathophysiological process. A physiological or psychological insult, for example, acute enteric infection, leads to loss of tolerance to a previously tolerated oral food antigen. This enables interaction of both the microbiota and the food antigen itself with the immune system, causing a localised immunological response, with activation of eosinophils and mast cells, and release of inflammatory mediators, including histamine and cytokines. These have more widespread systemic effects, including triggering nociceptive nerves and altering mood. Dietary interventions, including a diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols, elimination of potential food antigens or gluten, IgG food sensitivity diets or salicylate restriction may benefit some patients with IBS or FD. This could be because the restriction of these foods or dietary components modulates this pathophysiological process. Similarly, drugs including proton pump inhibitors, histamine-receptor antagonists, mast cell stabilisers or even tricyclic or tetracyclic antidepressants, which have anti-histaminergic actions, all of which are potential treatments for FD and IBS, act on one or more of these mechanisms. It seems unlikely that food antigens driving intestinal immune activation are the entire explanation for postprandial symptoms in FD and IBS. In others, fermentation of intestinal carbohydrates, with gas release altering reflex responses, adverse reactions to food chemicals, central mechanisms or nocebo effects may dominate. However, if the concept that postprandial symptoms arise from food antigens driving an immune response in the gastrointestinal tract in a subset of patients is correct, it is paradigm-shifting, because if the choice of treatment were based on one or more of these therapeutic targets, patient outcomes may be improved.

Does Cell-Type-Specific Silencing of Monoamine Oxidase B Interfere with the Development of Right Ventricle (RV) Hypertrophy or Right Ventricle Failure in Pulmonary Hypertension?

Increased mitochondrial reactive oxygen species (ROS) formation is important for the development of right ventricular (RV) hypertrophy (RVH) and failure (RVF) during pulmonary hypertension (PH). ROS molecules are produced in different compartments within the cell, with mitochondria known to produce the strongest ROS signal. Among ROS-forming mitochondrial proteins, outer-mitochondrial-membrane-located monoamine oxidases (MAOs, type A or B) are capable of degrading neurotransmitters, thereby producing large amounts of ROS. In mice, MAO-B is the dominant isoform, which is present in almost all cell types within the heart. We analyzed the effect of an inducible cardiomyocyte-specific knockout of MAO-B (cmMAO-B KO) for the development of RVH and RVF in mice. Right ventricular hypertrophy was induced by pulmonary artery banding (PAB). RV dimensions and function were measured through echocardiography. ROS production (dihydroethidium staining), protein kinase activity (PamStation device), and systemic hemodynamics (in vivo catheterization) were assessed. A significant decrease in ROS formation was measured in cmMAO-B KO mice during PAB compared to Cre-negative littermates, which was associated with reduced activity of protein kinases involved in hypertrophic growth. In contrast to littermates in which the RV was dilated and hypertrophied following PAB, RV dimensions were unaffected in response to PAB in cmMAO-B KO mice, and no decline in RV systolic function otherwise seen in littermates during PAB was measured in cmMAO-B KO mice. In conclusion, cmMAO-B KO mice are protected against RV dilatation, hypertrophy, and dysfunction following RV pressure overload compared to littermates. These results support the hypothesis that cmMAO-B is a key player in causing RV hypertrophy and failure during PH.

Disturbances of Ruminal Microbiota and Liver Inflammation, Mediated by LPS and Histamine, in Dairy Cows Fed a High-Concentrate Diet

The ecosystem of ruminal microbiota profoundly affects the health and milk production of dairy cows. High-concentrate diets are widely used in dairy farms and evoke a series of metabolic disorders. Several studies have reported the effects of high-concentrate diets on the ruminal microbiome, while the effect of changes in ruminal microbial flora, induced by high-concentrate diet feeding, on the liver of dairy cows has not been studied before. In this study, 12 mid-lactating Holstein Friesian cows (weight of 455 ± 28 kg; parities of 2.5 ± 0.5; starting milk yield of 31.59 ± 3.2 kg/d; DMI of 21.7 ± 1.1 kg/d; and a DIM at the start of the experiment of 135 ± 28 d) were fitted with ruminal fistulas, as well as with portal and hepatic vein catheters. All cows were randomly divided into 2 groups; then, they fed with low-concentrate diets (LC, concentrate: forage = 40:60) and high-concentrate diets (HC, concentrate: forage = 60:40) for 18 weeks. The forage sources were corn silage and alfalfa hay. After the cows of two groups were euthanized over two consecutive days, ruminal microbiota; the concentration of LPS in the rumen content; cecum content; the levels of blood and histamine in rumen fluid, blood, and the liver; the histopathological status of the rumen and cecum; and the inflammatory response of the liver were assessed in dairy cows under conditions of subacute ruminal acidosis (SARA). These conditions were caused by high-concentrate diet feeding. All data were analyzed using the independent t-test in SPSS. The results showed that high-concentrate diet feeding increased the concentration of LPS and histamine in the rumen and plasma of veins (p < 0.05). The abundance of Bacteroidetes at the phylum level, and of both Bacteroidetes and Saccharibacteria at the genus level, was decreased, while the abundance of Firmicutes at the phylum level and Oscillibacter at the genus level was increased by high-concentrate diet feeding. The decreased pH values of ruminal contents (LC = 6.02, HC = 5.90, p < 0.05) and the increased level of LPS in the rumen (LC = 4.921 × 105, HC = 7.855 × 105 EU/mL, p < 0.05) and cecum (LC = 11.960 × 105, HC = 13.115 × 105 EU/mL, p < 0.01) induced the histopathological destruction of the rumen and cecum, combined with the increased mRNA expression of IL-1β (p < 0.05). The histamine receptor H1R and the NF-κB signaling pathway were activated in the liver samples taken from the HC group. In conclusion, the elevated concentrations of LPS and histamine in the gut may be related to changes in the ruminal microbiota. LPS and histamine induced the inflammatory response in the ruminal epithelium, cecum epithelium, and liver. However, the cause-effect mechanism needs to be proved in future research. Our study offers a novel therapeutic strategy by manipulating ruminal microbiota and metabolism to decrease LPS and histamine release and to improve the health of dairy cows.

Histamine and receptors in neuroinflammation: Their roles on neurodegenerative diseases

Histamine, an auto-reactive substance and mediator of inflammation, is synthesized from histidine through the action of histidine decarboxylase (HDC). It primarily acts on histamine receptors in the central nervous system (CNS). Increasing evidence suggests that histamine and its receptors play a crucial role in neuroinflammation, thereby modulating the pathology of neurodegenerative diseases. Recent studies have demonstrated that histamine regulates the phenotypic switching of microglia and astrocytes, inhibits the production of pro-inflammatory cytokines, and alleviates inflammatory responses. In the CNS, our research group has also found that histamine and its receptors are involved in regulating inflammatory responses and play a central role in ameliorating chronic neuroinflammation in neurodegenerative diseases. In this review, we will discuss the role of histamine and its receptors in neuroinflammation associated with neurodegenerative diseases, potentially providing a novel therapeutic target for the treatment of chronic neuroinflammation-related neurodegenerative diseases in clinical settings.

Investigation of Biogenic Amine Levels and Microbiological Activity as Quality Markers in Some Dairy and Fish Products in Food Markets in the Kingdom of Saudi Arabia

This study aimed to verify the presence of biogenic amines (BAs) and evaluate the microbiological activity of some food samples collected from retail stores in the Kingdom of Saudi Arabia. A total of thirty-five dairy and fish products were collected and analyzed for BAs, including putrescine (PUT), cadaverine (CAD), spermidine (SPE), histamine (HIS), spermine (SPR), and tyramine (TYR), as well as for total colony count (TCC), lactic acid bacteria (LAB), Enterobacteriaceae, yeast and mold (Y and M), coliforms, and aerobic sporulation count (ASF). The thin layer chromatography (TLC) method was used in the analytical methodology to identify the BAs. The results showed the presence of BAs in all dairy products, but their concentration did not exceed the maximum permissible limit, which in contrast was established by the Food and Drug Administration (FDA) at 10 mg/100 g. The amounts of BAs in fish products varied significantly. All fish product samples contained levels of BAs below the permissible limit. Results of an independent study also indicated potential toxicity at levels of BAs (>10 mg/100 g) in Egyptian herring. Enterobacteriaceae and the coli group were present in higher concentrations in the Egyptian herring samples, whereas other samples (particularly frozen shrimp) showed increased TCC levels with a higher concentration of histamine-producing bacteria. From a consumer safety perspective, this study also indicated that food samples generally contained acceptable levels of BAs. In conclusion, there is a need to improve and standardize food quality and hygiene practices during production and storage to ensure human safety and prevent HIS formation.

Histamine Intolerance: Symptoms, Diagnosis, and Beyond

Histamine intolerance is a condition characterized by the accumulation of histamine to a point that exceeds the body's capacity to eliminate it. Researchers have attributed several reasons to this condition, such as genetic factors, alcohol, and dietary deficiencies, among other elements. Symptoms of histamine intolerance have been found to extend beyond the gastrointestinal tract and to the whole body, with these symptoms being sporadic and non-specific. This review will explore various aspects related to histamine intolerance, such as its causes, symptoms, diagnosis, and information related to management.

Pilot Study on the Prevalence of Diamine Oxidase Gene Variants in Patients with Symptoms of Histamine Intolerance

A retrospective pilot study was carried out to investigate the prevalence of four variants of the diamine oxidase (DAO) encoding gene (AOC1) in Caucasian adults with symptoms of histamine intolerance. In a cohort of 100 patients and 100 healthy individuals, DAO-encoding gene non-synonymous Single Nucleotide Variations (SNVs) were genotyped by multiplex single-nucleotide primer extension (SNPE) and capillary electrophoresis, and serum DAO activity was analyzed with a radio-extraction assay. The study found that 79% of individuals with symptoms of histamine intolerance harbored one or more of the four SNVs associated with reduced DAO activity. No significant differences were found in the prevalence of any variant between the group of patients and healthy controls. However, when considering the status of the alleles associated with DAO deficiency, more homozygous alleles were observed in histamine-intolerant patients. Moreover, a slightly but statistically higher percentage of patients had a high genetic risk score, reflecting the cumulative effect of carrying multiple DAO deficiency-associated gene variants and a high load of risk alleles (homozygous). A relationship between serum DAO activity and the genetic load of one specific SNV was observed, with DAO activity being significantly lower in patients homozygous for rs2052129. These results potentially support that carrying multiple DAO deficiency-associated gene variants and a high load of risk alleles (homozygous) is more relevant than the mere presence of one or more SNVs. Further studies are needed to determine the predictive value of these DAO-encoding gene variants.

Is calcitonin gene-related peptide (CGRP) the missing link in food histamine-induced migraine? A review of functional gut-to-trigeminovascular system connections

Calcitonin gene-related peptide (CGRP) and histamine plasma concentrations increase during migraine attacks. Both mediators are potent vasodilators, and they have been shown to reciprocally contribute to the release of each other in the trigeminovascular system, possibly driving migraine development. A high-histamine-content diet triggers migraine in patients who have histamine degradation deficiency owing to diaminooxidase (DAO) gene mutations. Therefore, studying functional links between exogenous histamine and CGRP seems promising for the understanding of diet-induced migraine generation. Notably, there is a lack of knowledge about the interplay of the enteric nervous system and the spinal/trigeminal somatosensory system with regard to CGRP and histamine. Based on background evidence, we propose that a functional interconnection between exogenous histamine and CGRP contributes to migraine development.

Enhanced mucosal mitochondrial function corrects dysbiosis and OXPHOS metabolism in IBD

Background

Mitochondrial (Mito) dysfunction in IBD reduces mucosal O2 consumption and increases O2 delivery to the microbiome. Increased enteric O2 promotes blooms of facultative anaerobes (eg. Proteobacteria ) and restricts obligate anaerobes (eg. Firmicutes ). Dysbiotic metabolites negatively affect host metabolism and immunity. Our novel compound (AuPhos) upregulates intestinal epithelial cell (IEC) mito function, attenuates colitis and corrects dysbiosis in humanized Il10-/- mice. We posit that AuPhos corrects IBD-associated dysbiotic metabolism.

Methods

Primary effect of AuPhos on mucosal Mito respiration and healing process was studied in ex vivo treated human colonic biopsies and piroxicam-accelerated (Px) Il10-/- mice. Secondary effect on microbiome was tested in DSS-colitis WT B6 and germ-free 129.SvEv WT or Il10-/- mice reconstituted with human IBD stool (Hu- Il10-/- ). Mice were treated orally with AuPhos (10- or 25- mg/kg; q3d) or vehicle, stool samples collected for fecal lipocalin-2 (f-LCN2) assay and microbiome analyses using 16S rRNA sequencing. AuPhos effect on microbial metabolites was determined using untargeted global metabolomics. AuPhos-induced hypoxia in IECs was assessed by Hypoxyprobe-1 staining in sections from pimonidazole HCl-infused DSS-mice. Effect of AuPhos on enteric oxygenation was assessed by E. coli Nissle 1917 WT (aerobic respiration-proficient) and cytochrome oxidase (cydA) mutant (aerobic respiration-deficient).

Results

Metagenomic (16S) analysis revealed AuPhos reduced relative abundances of Proteobacteria and increased blooms of Firmicutes in uninflamed B6 WT, DSS-colitis, Hu-WT and Hu- Il10-/- mice. AuPhos also increased hypoxyprobe-1 staining in surface IECs suggesting enhanced O2 utilization. AuPhos-induced anaerobiosis was confirmed by a significant increase in cydA mutant compared to WT (O2-utlizing) E.coli . Ex vivo treatment of human biopsies with AuPhos showed significant increase in Mito mass, and complexes I and IV. Further, gene expression analysis of AuPhos-treated biopsies showed increase in stem cell markers (Lgr4, Lgr5, Lrig1), with concomitant decreases in pro-inflammatory markers (IL1β,MCP1, RankL). Histological investigation of AuPhos-fed Px- Il10-/- mice showed significantly decreased colitis score in AuPhos-treated Px- Il10-/- mice, with decrease in mRNA of pro-inflammatory cytokines and increase in Mito complexes ( ND5 , ATP6 ). AuPhos significantly altered microbial metabolites associated with SCFA synthesis, FAO, TCA cycle, tryptophan and polyamine biosynthesis pathways. AuPhos increased pyruvate, 4-hydroxybutyrate, 2-hydroxyglutarate and succinate, suggesting an upregulation of pyruvate and glutarate pathways of butyrate production. AuPhos reduced IBD-associated primary bile acids (BA) with concomitant increase in secondary BA (SBA). AuPhos treatment significantly decreased acylcarnitines and increased L-carnitine reflective of enhanced FAO. AuPhos increases TCA cycle intermediates and creatine, energy reservoir substrates indicating enhanced OxPHOS. Besides, AuPhos also upregulates tryptophan metabolism, decreases Kynurenine and its derivatives, and increases polyamine biosynthesis pathway (Putresceine and Spermine).

Conclusion

These findings indicate that AuPhos-enhanced IEC mitochondrial function reduces enteric O2 delivery, which corrects disease-associated metabolomics by restoring short-chain fatty acids, SBA, AA and IEC energy metabolism.

Graphical abstract

New insights into the toxicological effects of dietary biogenic amines

Biogenic amines (BA) are molecules with biological functions, which can accumulate at toxic concentrations in foods. Several microorganisms have been identified as responsible for their accumulation at elevated concentrations. Histamine, tyramine and putrescine are the BA most commonly found at highest concentrations. The ingestion of food containing high BA concentrations leads to intoxication with symptoms depending on the BA and the amount consumed. Moreover, there is evidence of synergy between different BA, something of toxicological importance given that some foods accumulate different BA. This work reviews the BA toxic effects and examines recent discoveries regarding their synergy, cytotoxicity and genotoxicity. These advances in the toxicological consequences of ingesting BA contaminated foods support the need to regulate their presence in foods to preserve the consumer's health. However, more research efforts -focused on the establishment of risk assessments- are needed to reach a consensus in their limits in different food matrices.

Exploring the Relationship between Diamine Oxidase and Psychotropic Medications in Fibromyalgia Treatment, Finding No Reduction in Diamine Oxidase Levels and Activity except with Citalopram

Background: Histamine intolerance manifests when there is an imbalance between the production of histamine and the body's capacity to metabolise it. Within the gastrointestinal tract, diamine oxidase (DAO) plays a pivotal role in breaking down ingested histamine. Insufficient levels of DAO have been linked to various diseases affecting the respiratory, cardiovascular, nervous, muscular, and digestive systems; some of these symptoms are evidenced in fibromyalgia syndrome. This underscores the crucial role of DAO in maintaining the histamine balance and highlights its association with diverse physiological systems and health conditions. The management of fibromyalgia commonly involves the use of psychotropic medications; however, their potential interactions with DAO remain not fully elucidated. Methods: This study delved into the influence of various psychotropic medications on DAO activity through in vitro experiments. Additionally, we explored their impact on the human intestinal cell line Caco-2, examining alterations in DAO expression at both the mRNA and protein levels along with DAO activity. Results: Notably, the examined drugs-sertraline, pregabalin, paroxetine, alprazolam, and lorazepam-did not exhibit inhibitory effects on DAO activity or lead to reductions in DAO levels. In contrast, citalopram demonstrated a decrease in DAO activity in in vitro assays without influencing DAO levels and activity in human enterocytes. Conclusions: These findings imply that a collaborative approach involving psychotropic medications and DAO enzyme supplementation for individuals with fibromyalgia and a DAO deficiency could offer potential benefits for healthcare professionals in their routine clinical practice.

A review of biogenic amines in fermented foods: Occurrence and health effects

Biogenic amines (BAs) are low-molecular decarboxylation products of amino acids formed during microbial fermentation. Several fermented foods may contain BAs such as histamine, tyramine, and/or phenylethylamine, at levels above documented toxic doses. Dietary exposure to foods containing high levels of BAs is associated with many adverse health effects, such as migraines, elevated blood pressure, and tachycardia. BA-mediated toxicity may occur at levels a hundred times below regulatory and suggested toxic doses, depending on an individual's sensitivity and factors such as alcohol consumption and certain medications. Although BAs occur in a wide variety of fermented foods, food safety and public health professionals are not well informed about the potential health risks and control strategies in these foods. In this review, we highlight the health risks and symptoms linked to BA exposures, the BA levels found in different fermented foods, regulatory and suggested toxic doses, and risk mitigation strategies to inform food industry and public health professionals' practice.

Inhibitory effect of rosmarinic acid on IgE-trigged mast cell degranulation in vitro and in vivo

BACKGROUND

Rosmarinic acid (RA), a polyphenol from edible-medical Lamiaceae herbs, is known to possess a variety of pharmacological activity, like anti-inflammatory, hepatoprotective and immunoregulation activities.

METHODS AND RESULTS

Hereon, we investigated the anti-allergic activity of RA on immunoglobulin E (IgE)-mediated anaphylaxis responses in rat basophilic leukemia (RBL)-2H3 mast cell. RA hindered the morphological changes of IgE-induced degranulated RBL-2H3 cells. The release of two key biomarkers (β-hexosaminidase (β-HEX) and histamine) of IgE-induced degranulated mast cells was also remarkably down-regulated by RA intervention in a dose dependent manner. Moreover, RA inhibited IgE-induced ROS overproduction and flux of intracellular Ca2+ in IgE-mediated degranulated mast cells. The q-PCR analysis showed that the expressions of genes (COX 2, PGD 2, LTC 4, HDC, Nrf2, HO-1 and NQO1) involved in MAPK and oxidative stress signaling pathways were significantly regulated by RA intervention. Moreover, the degranulation inhibitory effect of rosmarinic acid was investigated on the anti-DNP IgE/DNP-HSA induced passive cutaneous anaphylaxis (PCA) mice model in vivo. It showed that RA significantly inhibited the PCA reaction and allergic edema of ears in anti-DNP IgE/DNP-HSA stimulated mice.

CONCLUSION

These findings suggest that RA has the potential to be used as a therapeutic candidate for allergic diseases by inhibiting mast cell degranulation. This indicates a possible role for RA in managing allergic reactions and related conditions.

Variability in feed intake the first days following weaning impacts gastrointestinal tract development, feeding patterns, and growth performance in nursery pigs

The present study investigated the effects of voluntary feed intake (FI) the first days after weaning on gastrointestinal development and protein fermentation the first week after weaning and growth performance and feeding patterns during the nursery phase. A total of 144 mixed-sex weaned pigs (24 ± 2 d old; 7.2 ± 0.8 kg body weight [BW]) were allocated to 12 pens with 12 pigs/pen. Each pen was equipped with an electronic feeding station for monitoring individual FI during a 40-d study. Pigs were classified based on their cumulative FI over the initial 3 d after weaning (FId1-3) being above or below their pen median FId1-3 (high = 919 ± 244 g or low = 507 ± 222 g FId1-3). Similarly, weaning BW classes (BW0; high = 7.72 ± 0.59 kg or low = 6.62 ± 0.88 kg BW) were created to study interactions with FId1-3. Two female pigs with either a high or a low FId1-3 per pen (n = 24) were selected for sampling at d6 and were used to study gastrointestinal development and fermentation products in the small intestine. Feeding patterns per day, FI, and growth performance were measured individually. Low FId1-3 pigs had lower (P < 0.05) daily FI during d0 to d8, d8 to d15, and d22 to d28, BW on d15, d22, d29, and d40, and average daily gain during d0 to d8, d22 to d29, and d29 to d40 compared to high FId1-3. High FId1-3 pigs increased (P < 0.05) the number of visits to the feeder between d1 to d13 and d31 to d35, and the time spent per visit only for d1 to d4 (P < 0.05). The daily rate of FI (g/min) was higher (P < 0.05) for High FId1-3 pigs on d6, d8, d9, and d10, and again several days later (d20 to d39). In addition, the high FId1-3 × high BW0 interaction improved daily FI during d18 to d40 compared to low FId1-3 × low BW0 class (P < 0.05). For the sampling on d6, low FId1-3 pigs had a lighter small intestine, colon, and pancreas, and reduced villi length, smaller villi surface area, and a lower number of goblet cells size in jejunum (P < 0.05), while concentrations of lactic acid, histamine, and cadaverine in small intestinal content were increased (P < 0.05). In conclusion, pigs with high FId1-3 became faster eaters with higher FI and growth rates toward the second half of the nursery, which was similar and additive for pigs with higher weaning BW. High FId1-3 was also associated with greater development of the gastrointestinal tract and a reduced protein fermentation 1-wk after weaning.