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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. [ABSTRACT FROM AUTHOR]

We studied the effects of some nitrogen-containing, heterocyclic, and cyclic compounds on the rate of oxidative deamination of polyamines and putrescine in tissues with a high proliferation rate. For this purpose, the specific activities of the main enzymes of polyamine oxidative degradation — spermine oxidase (SMO), polyamine oxidase (PAO), and diamine oxidase (DAO) were determined using a cell-free test system from regenerating rat liver. The compounds methyl 2-(5-formylfuran-2-yl)benzoate and 2,7-bis-[2-(diethylamino)ethoxy]-9H-fluoren-9-one (and in the form of dihydrochloride) showed mainly activating effect on oxidative degradation of putrescine, spermidine, and spermine, which indirectly indicates their antiproliferative effect. Nitrogen-free compounds inhibited this process, thus exhibiting potentially carcinogenic properties. Correlations were calculated for activity of DAO, PAO, and SMO with 5 topological indices: Wiener (W), Rouvray (R), Balaban (J) in the Trinaistich modification, detour (Ip), and electropy (Ie). The highest dependence was noted for DAO and the Balaban index (R=-0.55), for PAO and the detour index (R=0.78), and for SMO and the electropy index (R=0.53). The remaining dependencies showed insignificant correlation strength. [ABSTRACT FROM AUTHOR]

Atopic dermatitis (AD) remains a significant challenge due to its chronic and relapsing nature, with various triggers exacerbating symptoms. While endogenous histamine's role in AD is well documented, the impact of exogenous histamine remains controversial. This review explores the complex relationship between exogenous histamine and AD flare-ups, evaluating evidence for implementing low-histamine diets and diamine oxidase enzyme supplementation as a potential therapeutic intervention in a subgroup of AD patients. Histamine's diverse physiological functions, its involvement in AD pathophysiology, and the potential implications of histamine intolerance and histamine overlay syndrome are examined. Studies suggest compromised metabolism and increased sensitivity to dietary histamine, highlighting the potential of low-histamine diets in managing symptoms. Despite limited research, preliminary findings underscore the need for further exploration of histamine-related reactions in AD and the therapeutic potential of low-histamine diets. Future research avenues include developing reliable screening tools and elucidating the relationships between gut microbiome dysbiosis and histamine metabolism in AD. [ABSTRACT FROM AUTHOR]

Objective To observe the changes in levels of serum high-mobility group protein B1 (HMGB1) level and intestinal mucosal permeability (IP)-related indicators [D-lactic acid (D-lac), diamine oxidase (DAO), and endotoxin (ET)] in patients with liver cirrhosis, and to analyze the correlations between the level of serum HMGB1 and IP-related indicators to clarify the relationship between the level of serum HMGB1 and the IP of patients. Methods Sixty-three patients with liver cirrhosis were enrolled. According to the Child-Pugh score, the patients were divided into the CP-A group (n=16), CP-B group (n=32) and CP-C group (n=15)；33 cases of healthy people who underwent physical examination in the same period were used as the control group. The serum levels of HMGB1, ET, DAO and D-lac were detected by ELISA. The correlation between serum HMGB1, IP-related indicators and Child-Pugh classification, and the correlation between serum HMGB1 and IP-related indicators in patients with liver cirrhosis were analyzed. Results The levels of HMGB1, ET, DAO and D-lac in the CP-A, CP-B and CP-C groups were higher than those in the control group, the levels of HMGB1, D-lac and ET in the CP-C group were higher than those in the CP-A group, and the levels of HMGB1 and ET in the CP-B group were higher than those in the CP-A group (all P<0. 05). Serum HMGB1 was positively correlated with IP-related indicators ET, DAO and D-lac (r = 0. 371, 0. 854, 0. 623, all P<0. 05). The serum levels of HMGB1, ET, DAO and D-lac in patients with liver cirrhosis were positively correlated with Child-Pugh classification (r = 0. 356, 0. 272, 0. 301 and 0. 382, respectively, all P<0. 05). Conclusion The serum HMGB1 level in patients with liver cirrhosis increases, and IP increases, and they change more significantly with the severity of the disease； there is a positive correlation between the serum HMGB1 level and the patients' IP. [ABSTRACT FROM AUTHOR]

Oral submucous fibrosis (OSMF), a potentially malignant disorder, is developed by progressive fibrous tissue deposition in connective tissue along with atrophy of oral mucosa. Histological sections also show the mast cell infiltration in submucosa which may indicate their possible role in this entity. Abundant availability of biochemicals in mast cells like histamine and serine proteases like chymase may be released and play specific pathways in the disease pathophysiology. Possibly, if the histamine release has some part to play, diamine oxidase may also be found to have a relationship as it metabolizes histamine. The present study is proposed to identify the presence of chymase, histamine, and diamine oxidase in both, serum as well as tissue by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) respectively. This study may provide probable insight into the mast cell-related chemicals and their association with OSMF.

Oral submucous fibrosis (OSMF), a potentially malignant disorder, is developed by progressive fibrous tissue deposition in connective tissue along with atrophy of oral mucosa. Histological sections also show the mast cell infiltration in submucosa which may indicate their possible role in this entity. Abundant availability of biochemicals in mast cells like histamine and serine proteases like chymase may be released and play specific pathways in the disease pathophysiology. Possibly, if the histamine release has some part to play, diamine oxidase may also be found to have a relationship as it metabolizes histamine. The present study is proposed to identify the presence of chymase, histamine, and diamine oxidase in both, serum as well as tissue by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) respectively. This study may provide probable insight into the mast cell-related chemicals and their association with OSMF.

In this work, the diamine oxidase (DAO) produced from pea seedlings was partially purified using ammonium sulphate precipitation, dialysis, and gel filtration chromatography. Partially purified DAO was immobilized covalently with the help of a cross-linker glutaraldehyde onto the chitosan- modified gold electrode. The properties of immobilized enzyme were evaluated by optimum pH, optimum temperature, activity recovery, and recyclability using putrescine dihydrochloride as substrate. After immobilization of DAO, optimum pH ranges from 6.0 to 7.0 did not change and optimum temperature of enzyme changed from 34 to 38°C in comparison to free DAO. The immobilized DAO preserved 81% activity of free DAO and permitted increased stability and reusability of the enzyme than its native form. After 15 cycles of usage, the immobilized DAO maintained around 51% of its original activity, and this activity prolonged for 30 days at 4°C. [ABSTRACT FROM AUTHOR]

Copyright of Medicina Pro Praxi is the property of SOLEN sro and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Knowledge of the effect of different copper (Cu) chemical forms and their application mode on meeting the plant's Cu requirement is much more limited than that of other micronutrients. In this work, hydroponically-grown tobacco (Nicotiana rustica L.) plants were pre-cultured for thirty days under Cu-sufficient and Cu-deficient conditions, then the Cu-deficient plants were resupplied with 0.5 µM CuSO4 (CuSu) or Cu tetraamine sulfate complex ([Cu(NH3)4]SO4) (CuAm) through roots or leaves. The biomass of plants was resumed almost equally by both chemical forms of Cu. Cu's leaf and root concentrations exhibited a more pronounced response to CuSu application. In contrast, the restoration of the activities of Cu-containing enzymes (superoxide dismutase, polyphenol oxidase, diamine oxidase) was either similar to or, in some cases, even higher when CuAm was applied. The leaf iron concentration was also diminished under Cu starvation and increased by Cu resupply more effectively by CuAm. The activity of phenylalanine ammonia-lyase and peroxidase, phenolics accumulation, and lignin deposition was significantly influenced by Cu deficiency and resupply. Foliar-applied CuAm and root-applied CuSu were the most effective treatments for the resumption of lignin concentration. Results showed efficient re-translocation of foliar-applied Cu. However, the activity of defense enzymes and lignin content suggests that foliar spraying likely induced mechanical stress in the leaves. Furthermore, the effect of the accompanying ion (NH4+) was likely the mechanism for the superior effect of CuAm in the induction of structural strength through lignin deposition and improvement of Fe uptake in plants compared with CuSu. [ABSTRACT FROM AUTHOR]

Carbohydrates and gamma-amino butyric acid (GABA) have not been studied under the stress of stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) in wheat. Wheat cultivars PBW725 (resistant) and HD2967 (susceptible) were compared at 1, 2 and 4 d of GABA, Pst, and GABA + Pst sprayed to 30-d of seedling growth. Starch was hydrolyzed, and levels of sugars and proteins improved over time of infection in PBW725 however HD2967 improved under GABA + Pst. Proline increased while GABA decreased over the time of infection in HD2967. Progressive increase of diamine oxidase and glutamate decarboxylase was seen in PBW725 during infection. Protease levels became low at 4 d of infection but improved under GABA + Pst in HD2967. Protein carbonyls increased in HD2967 only under Pst but decreased under GABA + Pst. Results concluded that GABA is an essential regulator of carbohydrates under stripe rust. Sustained response over time of infection may be important for resistance. [ABSTRACT FROM AUTHOR]

Copyright of Türkiye Klinikleri Journal of Veterinary Sciences is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Oral submucous fibrosis (OSMF), a potentially malignant disorder, is developed by progressive fibrous tissue deposition in connective tissue along with atrophy of oral mucosa. Histological sections also show the mast cell infiltration in submucosa which may indicate their possible role in this entity. Abundant availability of biochemicals in mast cells like histamine and serine proteases like chymase may be released and play specific pathways in the disease pathophysiology. Possibly, if the histamine release has some part to play, diamine oxidase may also be found to have a relationship as it metabolizes histamine. The present study is proposed to identify the presence of chymase, histamine, and diamine oxidase in both, serum as well as tissue by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) respectively. This study may provide probable insight into the mast cell-related chemicals and their association with OSMF.

ABSTRACTDevelopment of two biosensors to detect biogenic amines was carried out using immobilized diamine oxidase from Pisum sativum on 3-APTMS-functionalized SiO2 substrates with either glutaraldehyde or terephthalaldehyde as crosslinkers. The assembly process was validated by FT-IR, SEM-EDX, and AFM. Biosensor responses to biogenic amines were c.a. 3-fold lower compared to the free enzyme kinetics as assessed by UV/VIS spectrophotometry. The calculated initial velocities (ΔAbs·min-1) for glutaraldehyde and terephthalaldehyde biosensors in the given order were (3.2 ± 0.68) × 10–2, (0.48 ± 0.09) × 10–2 for putrescine; (4.6 ± 1.2) × 10–2, (0.35 ± 0.47) × 10–2 for cadaverine; (5.8 ± 2.4) × 10–3, (19.0 ± 155) × 10–3 for spermidine, and (3.0 ± 2.0) × 10–4, (0.0 ± 7) × 10–4for histamine. The 2-way t-tests indicated that the crosslinker type affected the catalytic activity of immobilized diamine oxidase as the responses of glutaraldehyde biosensors to putrescine and cadaverine were significantly higher than those of the terephthalaldehyde. Molecular Docking simulations showed that glutaraldehyde has a stronger affinity for DAO’s lysine and arginine residues while terephthalaldehyde to phenylalanine.

Abstract Background The elevated circulating toxins secondary to the impairment of intestinal barrier integrity commonly elicit a chronic inflammatory response and finally contribute to multiple diseases. These toxins, including bacterial by-products and heavy metals, are the potent risk factors for the development of recurrent spontaneous abortion (RSA). Preclinical evidence suggests that several dietary fibers can restore intestinal barrier function and decrease the accumulation of heavy metals. However, it is uncertain whether treatment with a newly developed blend of dietary fibers product (Holofood) benefits patients with RSA. Methods In this trial, we enrolled 70 adult women with RSA, who were randomly assigned into the experiment group and the control group in a 2:1 ratio. Upon the basis of conventional therapy, subjects in the experiment group (n = 48) received 8 weeks oral administration with Holofood three times daily at a dose of 10 g each time. Subjects without Holofood consumption were set as the control (n = 22). Blood samples were collected for the determinations of metabolic parameters, heavy mental lead, and the indices related to intestinal barrier integrity (d-lactate, bacterial endotoxin, and diamine oxidase activity). Results The reduction amplitude in blood lead from baseline to week 8 was 40.50 ± 54.28 (μg/L) in the experiment group as compared with 13.35 ± 36.81 (μg/L) in the control group (P = 0.037). The decreased level of serum d-lactate from baseline to week 8 was 5.58 ± 6.09 (mg/L) in the experiment group as compared with − 2.38 ± 8.90 (mg/L, P

Lower urinary tract symptoms (LUTS) are highly prevalent, and their treatment is mainly focused on the control of symptoms. Histamine intolerance (HIT) has been related to a variety of systemic symptoms. DAO deficiency has been identified as a significant factor contributing to histamine intolerance (HIT). Preclinical evidence indicates the involvement of histamine in the lower urinary tract. This study aimed to assess the prevalence of diamine oxidase deficiency (DAO) in a prospective cohort of 100 patients with at least moderate LUTS. A genetic study of four single nucleotide polymorphisms (SNPs) (c.-691G>T, c.47C>T, c.995C>T, and c.1990C>G) was performed. HIT was found in 85.9% of patients. The prevalence of at least one minor allele in the SNPs analyzed was 88%, without gender differences. Storage symptoms were more intense in the presence of HIT as well as asthenia and neurological and musculoskeletal symptoms. The presence of minor alleles of the AOC1 gene was associated with a higher intensity of symptoms. Minor alleles from c.-691G>T and c.47C>T SNPs were also associated with a greater severity of obstructive symptoms. Thirty-one percent of patients presented the four SNPS with at least one associated minor allele. The relationship between HIT and LUTS in a mixed population of men and women found in this study supports further investigations to define the pathophysiology of histamine in LUTS. [ABSTRACT FROM AUTHOR]

Fibromyalgia (FM) is characterized by chronic musculoskeletal pain, muscle tension, joint mobility loss, and several psychological symptoms severely affecting patient well-being. Histamine is naturally degraded in the small intestine by diamine oxidase (DAO). Hereditary or acquired DAO deficiency causes extracellular histamine accumulation, leading to symptoms similar to those of individuals diagnosed with FM. Thus, this study aimed to assess the efficacy of adding DAO supplementation for 8 weeks to their standard therapy. We randomly assigned 100 women with FM (age: 33–61 years) to the supplementation and control groups. The Fibromyalgia Impact Questionnaire (FIQ), the Pain Catastrophizing Scale (PCS), and intensity scales were applied for a series of clinical symptoms together with the Bristol scale to assess the added value of DAO supplementation. Patients in both groups were receiving complete pharmacological support but some differences in the number of subjects receiving analgesics, antidepressants, and anxiolytics was noted. Patients in both study groups experienced favorable changes during the evaluation period as indicated by their final FIQ and PCS scores, particularly in the DAO group in the latter questionnaire. Qualitatively, the patients assigned to the DAO treatment group had lower scores for fatigue, anxiety, depression, burning and for rumination, magnification, and helplessness. [ABSTRACT FROM AUTHOR]

Histamine intolerance (HIT) is a clinical condition caused by decreased intestinal degradation of ingested histamine, primarily due to reduced enzyme diamine oxidase (DAO) activity, leading to histamine accumulation and causing various clinical manifestations. The measurement of serum DAO is commonly used as the main diagnostic test for HIT, although its diagnostic use is still uncertain. In this retrospective study, we aimed to assess the validity of DAO determination in patients with clinically suspected HIT. We measured DAO levels in 249 patients with suspected HIT and 50 healthy adult controls without HIT-related problems. Based on five clinical criteria, we divided patients into two groups: high (all five inclusion criteria; 41 patients) and low probability of HIT (≤4 inclusion criteria; 208 patients). Patients with a "high probability of HIT" had the lowest DAO (median: 8 U/mL, IQR: 6–10) in comparison to patients with a "low probability of HIT (median: 10 U/mL, IQR: 7–16, p = 0.0006) and healthy controls (median: 18 U/mL, IQR: 14–22, p < 0.0001). The specificity and sensitivity for DAO levels < 3/< 10 U/mL (manufacturer's set cut-off) to discriminate between patients with "high probability of HIT" and healthy controls were 100%/92% and 2%/71%. On the other hand, the specificity and sensitivity to discriminate between patients with "high probability of HIT" and "low probability of HIT" were 97%/61% and 2%/71%, respectively. Serum DAO determination represents an additional asset to the diagnosis of HIT based on clinical evaluation and assessment, but the diagnosis should not solely rely on DAO measurements. [ABSTRACT FROM AUTHOR]

Oral submucous fibrosis (OSMF), a potentially malignant disorder, is developed by progressive fibrous tissue deposition in connective tissue along with atrophy of oral mucosa. Histological sections also show the mast cell infiltration in submucosa which may indicate their possible role in this entity. Abundant availability of biochemicals in mast cells like histamine and serine proteases like chymase may be released and play specific pathways in the disease pathophysiology. Possibly, if the histamine release has some part to play, diamine oxidase may also be found to have a relationship as it metabolizes histamine. The present study is proposed to identify the presence of chymase, histamine, and diamine oxidase in both, serum as well as tissue by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) respectively. This study may provide probable insight into the mast cell-related chemicals and their association with OSMF.

Simple Summary: Biogenic amines (BAs) originate from amino acid decarboxylation and are commonly used as markers of spoilage and putrefaction in food and feed, especially in improperly handled animal products. Detoxification of BAs occurs mainly in the intestinal tract by amine oxidases, but some factors may facilitate intestinal absorption. When consumed in high concentrations, BAs can impair colonic epithelium, intestinal functionality, and may cause other toxicological effects. This study aimed to evaluate the effects of diets based on hydrolyzed protein (hydrolyzed chicken liver powder—HCLP) or conventional intact protein (poultry by-product meal—PBPM) with increasing protein concentrations (24, 32, and 40%) on the consumption and metabolism of biogenic amines in adult dogs. The results showed that PBPM had higher concentrations of putrefactive BAs, as well as the diets with its inclusion. As a result, dogs consumed higher concentrations of putrefactive BAs with diets containing PBPM and higher protein concentrations. Despite the difference in BAs concentrations in the protein sources, there was only an increase in the fecal excretion of phenylethylamine in the HCLP32 and HCLP40 diets and the enzymatic activity of monoamine oxidase in the HCLP24 and PBPM32 diets. Our findings indicate that the inclusion of HCLP reduces the consumption of putrefactive BAs and that the BAs detoxification system is highly efficient in the intestinal tract of dogs. Biogenic amines are synthesized through the bacterial decarboxylation of amino acids, commonly found in high levels in animal by-product meals due to spoilage. Furthermore, biogenic amines and other metabolites can be produced by the fermentation of proteins in the hindgut according to the protein source and concentration of crude protein (CP) in the diet. Thus, this study aimed to evaluate two protein sources (poultry by-product meal (PBPM) and hydrolyzed chicken liver powder (HCLP)) and three CP concentrations (24, 32, and 40%) and their effects on the consumption and fecal excretion of biogenic amines, plasma monoamine oxidase (MAO) and diamine oxidase (DAO) activities, and total antioxidant capacity (TAC) of healthy adult dogs after 30 days of feeding the experimental diets. Twelve dogs were randomly distributed into six treatments (n = 6/treatment): PBPM24 (PBPM with 24% CP); PBPM32 (PBPM with 32% CP); PBPM40 (PBPM with 40% CP); HCLP24 (HCLP with 24% CP); HCLP32 (HCLP with 32% CP); HCLP40 (HCLP with 40% CP). The PBPM and PBPM-based diets had higher concentrations of putrescine, cadaverine, tyramine, histamine, agmatine, and total biogenic amines. In contrast, HCLP and HCLP-based diets contained higher concentrations of spermidine, phenylethylamine, and spermine. The PBPM and PBPM-diets had higher biogenic amine index (BAI) indicating lower quality due to the high content of putrescine, cadaverine and tyramine. Dogs fed diets with PBPM and higher protein concentrations consumed more putrescine, cadaverine, tyramine, agmatine, and total amines (p < 0.0001), while dogs fed with HCLP consumed more spermidine, phenylethylamine, and spermine (p < 0.0001). Fecal excretion of phenylethylamine was greater in dogs fed HCLP32 and HCLP40 diets (p = 0.045). Dogs fed with HCLP tended to excrete more spermidine and tryptamine via feces, while higher protein concentrations tended to increase fecal excretion of cadaverine (p < 0.10). Plasma MAO activity was higher in dogs fed HCLP24 and PBPM32 diets (p = 0.024). The plasma activities of DAO and TAC were not different between diets (p > 0.05). Although we did not evaluate the intestinal activities of MAO and DAO, our results suggest that healthy adult dogs have an efficient deamination process on the gut epithelium. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of Yinlai Decoction (YD) on the microstructure of colon, and activity of D-lactic acid (DLA) and diamine oxidase (DAO) in serum of pneumonia mice model fed with high-calorie and high-protein diet (HCD). Methods: Sixty male Kunming mice were randomly divided into 6 groups by the random number table method: normal control, pneumonia, HCD, HCD with pneumonia (HCD-P), YD (229.2 mg/mL), and dexamethasone (15.63 mg/mL) groups, with 10 in each group. HCD mice were fed with 52% milk solution by gavage. Pneumonia mice was modeled with lipopolysaccharide inhalation and was fed by gavage with either the corresponding therapeutic drugs or saline water, twice daily, for 3 days. After hematoxylin-eosin staining, the changes in the colon structure were observed under light microscopy and transmission electron microscope, respectively. Enzyme-linked immunosorbent assay was used to detect the protein levels of DLA and DAO in the serum of mice. Results: The colonic mucosal structure and ultrastructure of mice in the normal control group were clear and intact. The colonic mucosal goblet cells in the pneumonia group tended to increase, and the size of the microvilli varied. In the HCD-P group, the mucosal goblet cells showed a marked increase in size with increased secretory activity. Loose mucosal epithelial connections were also observed, as shown by widened intercellular gaps with short sparse microvilli. These pathological changes of intestinal mucosa were significantly reduced in mouse models with YD treatment, while there was no significant improvement after dexamethasone treatment. The serum DLA level was significantly higher in the pneumonia, HCD, and HCD-P groups as compared with the normal control group (P<0.05). Serum DLA was significantly lower in the YD group than HCD-P group (P<0.05). Moreover, serum DLA level significantly increased in the dexamethasone group as compared with the YD group (P<0.01). There was no statistical significance in the serum level of DAO among groups (P>0.05). Conclusions: YD can protect function of intestinal mucosa by improving the tissue morphology of intestinal mucosa and maintaining integrity of cell connections and microvilli structure, thereby reducing permeability of intestinal mucosa to regulate the serum levels of DLA in mice. [ABSTRACT FROM AUTHOR]

Background: The elevated circulating toxins secondary to the impairment of intestinal barrier integrity commonly elicit a chronic inflammatory response and finally contribute to multiple diseases. These toxins, including bacterial by-products and heavy metals, are the potent risk factors for the development of recurrent spontaneous abortion (RSA). Preclinical evidence suggests that several dietary fibers can restore intestinal barrier function and decrease the accumulation of heavy metals. However, it is uncertain whether treatment with a newly developed blend of dietary fibers product (Holofood) benefits patients with RSA. Methods: In this trial, we enrolled 70 adult women with RSA, who were randomly assigned into the experiment group and the control group in a 2:1 ratio. Upon the basis of conventional therapy, subjects in the experiment group (n = 48) received 8 weeks oral administration with Holofood three times daily at a dose of 10 g each time. Subjects without Holofood consumption were set as the control (n = 22). Blood samples were collected for the determinations of metabolic parameters, heavy mental lead, and the indices related to intestinal barrier integrity (d-lactate, bacterial endotoxin, and diamine oxidase activity). Results: The reduction amplitude in blood lead from baseline to week 8 was 40.50 ± 54.28 (μg/L) in the experiment group as compared with 13.35 ± 36.81 (μg/L) in the control group (P = 0.037). The decreased level of serum d-lactate from baseline to week 8 was 5.58 ± 6.09 (mg/L) in the experiment group as compared with − 2.38 ± 8.90 (mg/L, P < 0.0001) in the control group. The change in serum DAO activity from baseline to week 8 was 3.26 ± 2.23 (U/L) in the experiment group as compared with − 1.24 ± 2.22 (U/L, P < 0.0001) in the control group. Participants who received Holofood had a greater decline in blood endotoxin from baseline to week 8 than those in the control group. Moreover, by comparing with the self-baseline, Holofood consumption significantly decreased the blood levels of lead, d-lactate, bacterial endotoxin, and DAO activity. Conclusion: Our results suggest that Holofood affords a clinically relevant improvements in blood lead level and intestinal barrier dysfunction in patients with RSA. [ABSTRACT FROM AUTHOR]

Histamine intolerance (HIT) is a common adverse reaction to food where elimination and reintroduction of histamine-rich food is part of the investigation. Analysis of the enzyme diamine oxidase (DAO) is sometimes used as an additional tool for diagnosis. This study aimed to describe the distribution of DAO in a large representative cohort of adults and to determine the association between DAO activity and possible associated factors. The study is based on the population-based West Sweden Asthma Study and includes 1051 subjects. Subjects underwent structured interviews including questions on demography, asthma, allergy symptoms, and lifestyle factors. Subjects were assessed for specific-IgE-antibodies and measurement of DAO activity in serum. Previously suggested cut-off levels for low values (<3 U/mL), normal values (>10 U/mL), and median levels of DAO were used. In the group of 1051 subjects, only a few presented reactions upon histamine intake, whereas 44% presented DAO levels below the suggested normal cut-off levels. BMI and age were shown to have an impact on DAO activity among women with increasing activity of DAO with increasing BMI and age. Among men, only increasing age was seen to have an impact on DAO levels. There was no difference in DAO levels with different sensitization status to common foods or airborne allergens. No association between DAO levels and reported symptoms to histamine-rich foods could be found. In conclusion, the determination of the DAO enzyme needs to be re-evaluated and may not be used as a valuable tool for histamine intolerance using current cut-off values. Further studies are needed to improve the use of DAO as a biomarker for histamine intolerance. [ABSTRACT FROM AUTHOR]

Background: Allergic rhinitis (AR) is characterized by the increased sensitivity of the nasal mucosa to allergens and has a significant impact on life quality. There is promising evidence that biomarkers can help in the diagnosis, treatment, and follow-up of patients with AR. Diamine oxidase (DAO) is one of the enzymes responsible for the breakdown of histamine, the primary mediator of allergies. Objective: To investigate the significance of DAO as a useful biomarker for diagnosis and the severity of AR. Methods: In this case-control study, 24 patients and 24 healthy controls were recruited and their serum DAO levels, total IgE levels (using ELISA), blood eosinophil count, and percentage (using complete blood cell count) were measured. The sino-nasal outcomes test-22 (SNOT-22) questionnaire was used to assess the severity of symptoms in patients. The Receiver Operating Characteristic (ROC) analysis was used to assess the predictive power of DAO level for the diagnosis of AR. The relationship between DAO and disease severity, as well as other AR-related clinical factors, were also investigated. Results: DAO levels were lower in AR patients compared with the controls. The DAO level did not significantly correlate with the severity of AR according to the Allergic Rhinitis and its Impact on Asthma (ARIA) score, though it was lower in patients with persistent or moderate to severe symptoms. The total IgE, eosinophil percentage, and SNOT-22 score all had an inverse relationship with DAO. Moreover, DAO was significantly associated with the diagnosis of AR, with an Area under the ROC Curve (AUC) of 0.771, a sensitivity of 75%, and a specificity of 62.5%. Conclusion: DAO might be a valuable biomarker in the diagnosis of allergic rhinitis.

Introduction: The amine oxidase copper-containing 1 (AOC1) gene encodes for the diamine oxidase (DAO) enzyme. DAO is an enzyme that catabolizes some molecules, including histamine, and is the degradative enzyme in the polyamine catabolic pathway that is active in intestinal mucosal cells. Variants of AOC1 are associated with reduced DAO activity, resulting in accumulation of high levels of histamine and causing a wide range of neurological, gastrointestinal, and epidermal disorders, which are present in people with fibromyalgia. This study aimed to evaluate the impact of four AOC1 gene variants, namely, rs10156191, rs1049742, rs1049793, and rs2052129, on fibromyalgia symptoms measured by the Fibromyalgia Impact Questionnaire (FIQ), such as sleep disorders, atopic dermatitis, migraine, gastrointestinal (GI) disorders, allergies, and intolerances, in adult women with fibromyalgia. Methods: The sample consisted of 100 unrelated women with fibromyalgia between 33 and 60 years of age (48.48 years ±7.35), whose were diagnosed by a rheumatologist based on symptoms such as pain, stiffness, and fatigue. Singlenucleotide polymorphisms (SNPs) of AOC1 were identified using oral mucosa samples collected following a standard hygiene protocol. DNA was extracted, and gene variants of interest were analyzed using multiplex single-nucleotide primer extension (SNPE). Clinical data were collected using the FIQ and a series of variables that quantified the intensity and frequency of the symptoms. Results: The minor allele frequencies of rs10156191, rs1049742, rs1049793, and rs2052129 were 31.5, 10, 32.5, and 27%, respectively. Each variant was found to be in Hardy–Weinberg equilibrium, but partial linkage disequilibrium between AOC1 SNPs is suspected. The results show that fibromyalgia symptoms measured using the FIQ tend to increase with the number of risk alleles and that the intensity of dry skin and low stool consistency may be associated with an increase in the number of these alleles. Conclusion: This study constitutes the first step in investigating associations between fibromyalgia symptoms and candidate variants of the AOC1 gene in DAO enzyme activity. Identification of reduced DAO activity may improve the quality of life and treatment of symptoms in fibromyalgia patients. [ABSTRACT FROM AUTHOR]

Introduction: The amine oxidase copper-containing 1 (AOC1) gene encodes for the diamine oxidase (DAO) enzyme. DAO is an enzyme that catabolizes some molecules, including histamine, and is the degradative enzyme in the polyamine catabolic pathway that is active in intestinal mucosal cells. Variants of AOC1 are associated with reduced DAO activity, resulting in accumulation of high levels of histamine and causing a wide range of neurological, gastrointestinal, and epidermal disorders, which are present in people with fibromyalgia. This study aimed to evaluate the impact of four AOC1 gene variants, namely, rs10156191, rs1049742, rs1049793, and rs2052129, on fibromyalgia symptoms measured by the Fibromyalgia Impact Questionnaire (FIQ), such as sleep disorders, atopic dermatitis, migraine, gastrointestinal (GI) disorders, allergies, and intolerances, in adult women with fibromyalgia.Methods: The sample consisted of 100 unrelated women with fibromyalgia between 33 and 60 years of age (48.48 years ±7.35), whose were diagnosed by a rheumatologist based on symptoms such as pain, stiffness, and fatigue. Single-nucleotide polymorphisms (SNPs) of AOC1 were identified using oral mucosa samples collected following a standard hygiene protocol. DNA was extracted, and gene variants of interest were analyzed using multiplex single-nucleotide primer extension (SNPE). Clinical data were collected using the FIQ and a series of variables that quantified the intensity and frequency of the symptoms.Results: The minor allele frequencies of rs10156191, rs1049742, rs1049793, and rs2052129 were 31.5, 10, 32.5, and 27%, respectively. Each variant was found to be in Hardy–Weinberg equilibrium, but partial linkage disequilibrium between AOC1 SNPs is suspected. The results show that fibromyalgia symptoms measured using the FIQ tend to increase with the number of risk alleles and that the intensity of dry skin and low stool consistency may be associated with an increase in the number of these alleles.Conclusion: This study constitutes the first step in investigating associations between fibromyalgia symptoms and candidate variants of the AOC1 gene in DAO enzyme activity. Identification of reduced DAO activity may improve the quality of life and treatment of symptoms in fibromyalgia patients.

This case study examines the kinetics of the diamine oxidase levels after challenge with a histamine-rich meal in patients with histamine intolerance as an alternative diagnostic tool to conventional tests combined with the dietary intervention.

The neurotoxin β-N-methylamino-L-alanine (BMAA) is a non-proteinogenic amino acid produced by cyanobacteria. Non-neuronal toxicity of BMAA is poorly studied with a reported increase in reactive oxygen species and a decrease in the antioxidant capacity of liver, kidney, and colorectal adenocarcinoma cells. The aim of this research is to study the toxicity of BMAA (0.1–1 mM) on mitochondria and submitochondrial particles with ATPase activity, on the semicarbazide-sensitive amino oxidases (SSAOs) activity of rat liver, and on an in vitro model containing functionally active excitable tissues—regularly contracting heart muscle preparation with a preserved autonomic innervation. For the first time the BMAA-dependent inhibition of SSAO activity, the elimination of the positive inotropic effect of adrenergic innervation, and the direct and reversible inhibition of adrenaline signaling in ventricular myocytes with 1 mM BMAA were observed. Additionally, it is confirmed that 1 mM BMAA can activate mitochondrial ATPase indirectly. It is concluded that a higher dose of BMAA may influence multiple physiological and pathological processes as it slows down the degradation of biogenic amines, downregulates the sympathetic neuromediation, and embarrasses the cell signaling of adrenergic receptors. [ABSTRACT FROM AUTHOR]

Development of two biosensors to detect biogenic amines was carried out using immobilized diamine oxidase from Pisum sativum on 3-APTMS-functionalized SiO2 substrates with either glutaraldehyde or terephthalaldehyde as crosslinkers. The assembly process was validated by FT-IR, SEM-EDX, and AFM. Biosensor responses to biogenic amines were c.a. 3-fold lower compared to the free enzyme kinetics as assessed by UV/VIS spectrophotometry. The calculated initial velocities (ΔAbs·min-1) for glutaraldehyde and terephthalaldehyde biosensors in the given order were (3.2 ± 0.68) × 10–2, (0.48 ± 0.09) × 10–2 for putrescine; (4.6 ± 1.2) × 10–2, (0.35 ± 0.47) × 10–2 for cadaverine; (5.8 ± 2.4) × 10–3, (19.0 ± 155) × 10–3 for spermidine, and (3.0 ± 2.0) × 10–4, (0.0 ± 7) × 10–4for histamine. The 2-way t-tests indicated that the crosslinker type affected the catalytic activity of immobilized diamine oxidase as the responses of glutaraldehyde biosensors to putrescine and cadaverine were significantly higher than those of the terephthalaldehyde. Molecular Docking simulations showed that glutaraldehyde has a stronger affinity for DAO's lysine and arginine residues while terephthalaldehyde to phenylalanine. [ABSTRACT FROM AUTHOR]

Idiopathic rhinitis represents more than 50% of non-allergic rhinitis, a heterogeneous group that involves the symptomatic inflammation of the nasal mucosa. The TRPV1 receptor of unmyelinated C-type neurons appears to be involved in its pathophysiology. Histamine, whose main catabolic enzyme is DAO, is one of the mediators that can activate this receptor. The failure of DAO causes an increase in the level of histamine in the body and, consequently, the activation of TRPV1. The objective was to investigate the existence of a DAO enzyme activity deficit in idiopathic rhinitis and its correlation with symptoms. A cross-sectional study was conducted in 116 idiopathic rhinitis patients, and DAO activity, nasal peak inspiratory flow, and rhinitis severity were recorded. The prevalence of a DAO activity deficit was 41.38% (95%CI 0.33–0.50; p = 0.05). The DAO activity in patients with mild rhinitis was 52.93 ± 8.72 HDU/mL, in those with moderate rhinitis it was 120.33 ± 71.63 HDU/mL, and in those with severe rhinitis it was 92.58 ± 27.75 HDU/mL (p = 0.006). The NPIF in patients with a DAO activity deficit was 107.92 ± 34.05 L/min, compared to 72.35 ± 27.16 L/min in patients with normal enzymatic activity (p < 0.001), demonstrating a linear correlation between activity levels and nasal obstruction (−0.45; p < 0.001). Therefore, patients with a DAO deficiency and idiopathic rhinitis could present a milder disease course, because the repeated and continuous activation of TRPV1 led to a partial or total decrease in their response (desensitization). This new theory represents a different perspective for the study of idiopathic rhinitis and its relationship with TRPV1, with the regulation or modulation of the desensitization of TRPV1 being an important therapeutic target for patients with idiopathic rhinitis in the future. [ABSTRACT FROM AUTHOR]

Azospirillum baldaniorum Sp 245 is a model plant growth-promoting rhizobacterium. The first cross-talk with plants takes place within the roots. Roots cells growth is constrained by the primary cell wall (CW). Also, neighboring CW form the apoplast that should affect cells signaling and biochemical messages. Studies on CW phenolic composition ferulate (FA), diferulates (DFA) and p-coumarate and polyamines (PA) metabolisms of A. baldaniorum Sp 245- inoculated roots and on bacterial PA production in culture media should help to understand more about the mechanisms involved in Azospirillum -root association. For this purpose, CW-bound FA, DFA and p-coumarate contents, putrescine (put) and spermidine contents, diamine and polyamine oxidases activities, and H2O2 content of Cucumis sativus roots from dark grown seedlings inoculated with A. baldaniorum Sp 245 were determined. Also, bacterial PA production under constant agitation or static conditions was evaluated. Results showed lesser contents of all phenolics, and higher FA/DFA ratio in CW of inoculated roots that should be responsible for roots growth promotion. Also, the increased put content, DAO activity, and H2O2 production in the roots should be associated to A. baldaniorum Sp 245 growth promotion in early stages. Finally, the participation of both PA in A. baldaniorum Sp 245 biofilm formation was demonstrated. [ABSTRACT FROM AUTHOR]

The serum level of diamine oxidase (DAO) reflects the integrity and maturation of the small intestinal mucosa. This measure is important in diagnosing various diseases, including chronic urticaria tachyphylaxis, multiple organ dysfunction syndrome, preterm abortion, and migraine. This review aimed to summarize the findings of previous studies on the changes in DAO levels in diverse diseases and the application of this enzyme in the clinical setting, as well as the roles of this enzyme under physiological and pathological conditions. The advances in the mechanism and clinical application of DAO presented in this review will contribute to a better understanding of this enzyme and open up new and broader perspectives for future basic research and clinical applications. [ABSTRACT FROM AUTHOR]

Passiflora edulis, commonly known as passion fruit, is a popular all‐weather fruit eaten fresh or processed. Its shells, which currently are mostly discarded as waste and hurt the environment, account for more than half of the passion fruit. The shells contain gamma‐aminobutyric acid (GABA) which is the main inhibitory neurotransmitter and has many proven medical values such as antidepressant, anti‐anxiety, etc. Many studies have shown that GABA production in plants can be significantly increased by reverse stress. Taking Tainong 1 as a typical passion fruit cultivar, this study explored the optimal anoxic vacuum treatment for increasing the GABA content of passion fruit shells. The content increased to 2139.25 ± 26.69 mg/100 g on day 4 of chill storage after vacuum packing (63.68% higher than the control). The activities of glutamate decarboxylase (GAD) and diamine oxidase (DAO) were significantly higher in the vacuum‐treated group than in the control group after 4 days of vacuum‐chill storage. On day 5 of vacuum‐chill storage, the activities of all measured enzymes decreased except for the increase of GABA transaminase (GABA‐T), which was accompanied by a decrease in GABA content. Vacuum treatment and subsequent chill storage increased the content of GABA, thereby increasing functional value of passion fruit shells. [ABSTRACT FROM AUTHOR]

Dual-enzyme co-embedded materials have shown high potential for achieving efficient detection due to the convenience of two-enzyme cascade reactions. Herein, we developed a dual-enzyme hybrid microsphere (HM) based biosensor to detect diamines (histamine was included for ease of description) in aquatic products. The HM was made from diamine oxidase, horseradish peroxidase, and copper phosphate through the biomineralization method. Under optimal conditions, the system displayed linear color response to histamine of different concentrations ranging from 0 to 200 μg/mL. The detection limit of histamine was 0.15 μg/mL, showing higher sensitivity than the two-step free enzyme assay. Moreover, the detection system exhibited good specificity to diamines. The method was used to detect diamines in commercial samples, and the results were compared with those measured by the high-performance liquid chromatography method. Overall, the proposed assay exhibited high potential in diamine quantification and was readily extended to other cascade enzymatic reaction-based detection strategies. • Dual enzyme-inorganic hybrid microsphere was synthesized through bio-mineralization. • A sensor-based on hybrid microspheres and TMB were constructed for detecting diamine. • Good sensitivity, specificity, and visual sensing have been obtained. • This sensor has promising detection performance in aquatic products. [ABSTRACT FROM AUTHOR]

Chronic urticaria is a polyetiological disease proceeding by various immunological and non-immunological (pseudo-allergic) mechanisms. Food intolerance is a distinct type of pseudo-allergies, manifesting, e.g., with histamine intolerance syndrome, caused by imbalance between the histamine accumulation and the ability to degrade it. The purpose of this article was to summarize results of recent studies, to discuss the difficulties of diagnosing this pathology, which primarily depends on the degree of impaired histamine degradation under the influence of diamine oxidase. Diamine oxidase is the main enzyme required for histamine destruction in the intestines, being synthesized by apical enterocytes. The review draws attention to the reasons leading to increased level of histamine not only with consumed food, given its different concentration in the same food products, depending, for example, on their processing and storage, but also with suppressing activity of the enzymes required for metabolism of histamine by various food additives, by the influence of microbiota. The results of studies in which the levels of histamine and/or diamine oxidase activity were determined, which depend on adherence to the diet confirming the association of diamine oxidase with the symptoms of histamine intolerance. According to most studies, the compliance with diet led to increased level of diamine oxidase. However, in some studies, no changes in the activity of this enzyme were found. There are several studies that have evaluated the levels of diamine oxidase in patients with true allergies. Moreover, some authors, in addition to adherence to the diet, evaluated the effectiveness of drugs containing diamine oxidase in patients with low levels of this enzyme in blood serum. The workers also confirm high proportion of histamine intolerance syndrome among various food reactions, suggesting a need for differential diagnosis with other non-immune reactions, including disorders of gastrointestinal tract and psychosomatic reactions. Thus, all the authors confirm the need for laboratory diagnosis of histamine intolerance syndrome, since this will not only increase the efficiency of dietary adherence, but also substantiate the usage of drugs containing diamine oxidase, which will improve quality of life in these cohorts. However, these patients are still treated with low-histamine diets. The literature data confirm the opportunity of using this histamine degradation enzyme as a biological marker of histamine intolerance syndrome, and recommend its assays for inclusion into the diagnostic algorithm for chronic urticaria.

Infection with Helicobacter pylori (H.pylori) may cause dyspepsia and/or unexplained functional nonspecific, gastrointestinal complaints of the irritable bowel syndrome (IBS) spectrum. Hitherto, in H. pylori infected patients with symptoms of the IBS spectrum the occurrence of additional food intolerance/malabsorption is not evaluated. We used a retrospective analysis of charts from 548 patients who presented with gastrointestinal complaints of the irritable bowel syndrome spectrum. An enzyme-linked IgA immunosorbent assay or histologic evaluation of gastric mucosa were used to detect H. pylori infection. A hydrogen breath (H2) test was performed to evaluate fructose malabsorption (FM) and lactose intolerance (LIT). Serum diamine oxidase value of

OBJECTIVE: Oxygen is essential for living organisms that perform aerobic respiration since cells begin to die when humans and animals are deprived of oxygen. Oxygen saturation decreases and shortness of breath occurs in coronavirus (COVID-19) disease. Therefore, in this study, we aimed to determine the changes in hypoxia-inducible factor-1α (HIF-1α), subfatin, asprosin, irisin, C-reactive protein (C-RP), Maresin-1 (MaR-1), and diamine oxidase (DAO) molecules in diabetic patients with coronavirus according to their oxygen saturations. PATIENTS AND METHODS: Participants were classified into 4 Groups of 22, including patients with oxygen saturation between 95% and 100% (Group I, control), between 80% and 85% (Group II), between 75% and 79% (Group III), and between 70% and 74% (Group IV). COVID-19 was diagnosed with PCR testing and 5 mL of blood was taken following the diagnosis. HIF-1α, subfatin, asprosin, irisin, MaR-1, and DAO values of the participants were measured with ELISA. Other parameters used in the study were obtained from the records of the patients. RESULTS: When Group I was compared to Groups II, there was no significant change in Group II while HIF-1α, subfatin, asprosin, irisin, C-RP, and DAO counts had increased significantly in Groups III and IV. When the MaR-1 values were examined, they were reported to have decreased significantly in Groups III and IV (p < 0.05). Similarly, when Group II and Group IV were compared, HIF-1α, subfatin, asprosin, irisin, C-RP, and DAO values of the participants in Group IV had significantly increased while MaR1 values had significantly decreased (p < 0.05). In the case of oxygen saturation decreasing below the critical value (70-74%) in patients with coronavirus, the release of HIF-1HIF-1α, subfatin, asprosin, irisin, C-RP, and DAO increased while the MaR-1 values decreased (p < 0.05). CONCLUSIONS: Changes in these molecules in patients with coronavirus and diabetes according to their oxygen saturation suggested that they functioned as the “metabolic oxygen sensors” of the metabolism. Therefore, according to these data, it was predicted that these molecules had the potential to be used in the diagnosis and follow-up of diseases related to oxygen (such as asthma, and critical intensive care patients) in clinics in the future. [ABSTRACT FROM AUTHOR]

The consumption of foods fraught with histamine can lead to various allergy-like symptoms if the histamine is not sufficiently degraded in the human body. The degradation occurs primarily in the small intestine, naturally catalyzed by the human diamine oxidase (DAO). An inherent or acquired deficiency in human DAO function causes the accumulation of histamine and subsequent intrusion of histamine into the bloodstream. The histamine exerts its effects acting on different histamine receptors all over the body but also directly in the intestinal lumen. The inability to degrade sufficient amounts of dietary histamine is known as the 'histamine intolerance'. It would be preferable to solve this problem initially by the production of histamine-free or -reduced foods and by the oral supplementation of exogenous DAO supporting the human DAO in the small intestine. For the latter, DAOs from mammalian, herbal and microbial sources may be applicable. Microbial DAOs seem to be the most promising choice due to their possibility of an efficient biotechnological production in suitable microbial hosts. However, their biochemical properties, such as activity and stability under process conditions and substrate selectivity, play important roles for their successful application. This review deals with the advances and challenges of DAOs and other histamine-oxidizing enzymes for their potential application as processing aids for the production of histamine-reduced foods or as orally administered adjuvants to humans who have been eating food fraught with histamine. [ABSTRACT FROM AUTHOR]

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Competing Interests: Declaration of competing interest none

Biogenic amines are synthesized through the bacterial decarboxylation of amino acids, commonly found in high levels in animal by-product meals due to spoilage. Furthermore, biogenic amines and other metabolites can be produced by the fermentation of proteins in the hindgut according to the protein source and concentration of crude protein (CP) in the diet. Thus, this study aimed to evaluate two protein sources (poultry by-product meal (PBPM) and hydrolyzed chicken liver powder (HCLP)) and three CP concentrations (24, 32, and 40%) and their effects on the consumption and fecal excretion of biogenic amines, plasma monoamine oxidase (MAO) and diamine oxidase (DAO) activities, and total antioxidant capacity (TAC) of healthy adult dogs after 30 days of feeding the experimental diets. Twelve dogs were randomly distributed into six treatments (n = 6/treatment): PBPM24 (PBPM with 24% CP); PBPM32 (PBPM with 32% CP); PBPM40 (PBPM with 40% CP); HCLP24 (HCLP with 24% CP); HCLP32 (HCLP with 32% CP); HCLP40 (HCLP with 40% CP). The PBPM and PBPM-based diets had higher concentrations of putrescine, cadaverine, tyramine, histamine, agmatine, and total biogenic amines. In contrast, HCLP and HCLP-based diets contained higher concentrations of spermidine, phenylethylamine, and spermine. The PBPM and PBPM-diets had higher biogenic amine index (BAI) indicating lower quality due to the high content of putrescine, cadaverine and tyramine. Dogs fed diets with PBPM and higher protein concentrations consumed more putrescine, cadaverine, tyramine, agmatine, and total amines (p < 0.0001), while dogs fed with HCLP consumed more spermidine, phenylethylamine, and spermine (p < 0.0001). Fecal excretion of phenylethylamine was greater in dogs fed HCLP32 and HCLP40 diets (p = 0.045). Dogs fed with HCLP tended to excrete more spermidine and tryptamine via feces, while higher protein concentrations tended to increase fecal excretion of cadaverine (p < 0.10). Plasma MAO activity was higher in dogs fed HCLP24 and PBPM32 diets (p = 0.024). The plasma activities of DAO and TAC were not different between diets (p > 0.05). Although we did not evaluate the intestinal activities of MAO and DAO, our results suggest that healthy adult dogs have an efficient deamination process on the gut epithelium.

As an important inflammatory mediator, histamine can be produced by many immune cells (mast cells, neutrophils, dendritic cells, platelets, etc.) and modulates a variety of immune events. Developing enzymatic micro/nanomotors from the perspective of immunometabolism is required but still lacking. In this work, we functionalized the histamine‐metabolizing enzyme onto the Janus Au/mSiO2 nanoparticles. Powered by the tandem catalytic decomposition of histamine initiated by a surface‐modified diamine oxidase, this nanomotor system exhibits an enhanced diffusive motion with increasing histamine concentration. At a concentration of histamine (500 mM), the motor speed reaches 9.25±1.71 μm.s−1, which is 2.3 times that of Brownian motion, and the corresponding diffusion coefficient is enhanced by 137%. This novel enzymatic nanomotor system not only expands the physiologic enzyme library for biomedical micro/nanomotors but also provides new ideas for the immune therapy of diseases targeting histamine. [ABSTRACT FROM AUTHOR]

A new diamine oxidase (DAO-1) was discovered recently in the yeast Yarrowia lipolytica PO1f and investigated for its histamine degradation capability under simulated intestinal conditions. DAO-1 was formulated together with catalase as a sucrose-based tablet. The latter (9 × 7 mm; 400 mg) contained 690 nkat of DAO-1 activity, which was obtained from a bioreactor cultivation of a genetically modified Y. lipolytica with optimized downstream processing. The DAO-1 tablet was tested in a histamine bioconversion experiment under simulated intestinal conditions in the presence of food constituents, whereby about 30% of the histamine was degraded in 90 min. This amount might already be sufficient to help people with histamine intolerance. Furthermore, it was found that the stability of DAO-1 in a simulated intestinal fluid is influenced distinctively by the presence of a food matrix, indicating that the amount and type of food consumed affect the oral supplementation with DAO. This study showed for the first time that a microbial DAO could have the potential for the treatment of histamine intolerance by oral supplementation. [ABSTRACT FROM AUTHOR]

The serum concentration and activity of diamine oxidase (DAO) in calves with or without diarrhea during the first month of life were examined. The serum DAO concentration was highest on day 0 after birth, and gradually decreased. No differences in serum DAO concentrations were observed between calves with diarrhea and control calves. In contrast, serum DAO activity was lowest on day 0 after birth, and gradually increased. Serum DAO activity in calves with diarrhea was lower than that in the control calves from day 20 after birth. These findings suggest that serum DAO activity and concentration are not correlated, and serum DAO activity is useful for assessing damage to the small intestinal mucosa in calves. [ABSTRACT FROM AUTHOR]

Background/objectives: Histamine has shown a possible role in the etiopathogenesis of migraine. It has been reported an association between some polymorphisms in the diamine oxidase (DAO) gene and migraine, especially in women. Two studies addressing DAO activity in migraine patients showed conflicting results. We investigated the possible relationship of serum DAO activity and histamine levels and 3 polymorphisms in the DAO gene with the risk for migraine. Methods: We studied the frequencies of DAO rs10156191, rs1049742 and rs1049793 genotypes and allelic variants in 298 migraine patients and 360 healthy controls (using a TaqMan‐based qPCR assay), and serum DAO activity and histamine levels in a subset of 99 migraine patients and 115 controls with strict exclusion criteria, and analysed the relationship of these variables with several clinical features of migraine. Results: The frequencies of the DAO genotypes and allelic variants analysed were similar in migraine patients and controls. Serum DAO activity was significantly higher in migraine patients (Vmax/Km 4.24 ± 2.93 vs. 3.60 ± 7.64, p < 0.001), especially in females (Vmax/Km 4.63 ± 2.96 vs. 3.18 ± 2.32, p < 0.0001), while serum histamine was similar in both study groups. Conclusion: Serum DAO activity was increased in patients with migraine, especially in females, while serum histamine levels were normal. None of the studied polymorphisms was associated with the risk for migraine. [ABSTRACT FROM AUTHOR]

The association between intestinal permeability and sarcopenia remains unclear, and few studies have mentioned the relationship between intestinal permeability and skeletal muscle strength. The present cross-sectional community study was conducted in a rural area of Beijing to explore the association between intestinal permeability and handgrip strength (HGS) in middle-aged and older adults. Serum lipopolysaccharide (LPS), diamine oxidase (DAO) and D-lactate were detected to evaluate intestinal permeability. Gut microbiota (GM) and its potential interaction were also analyzed in the decision tree model. HGS was negatively correlated with DAO (r = −0.396, p < 0.01) in males. The negative association between HGS and DAO remained significant with the adjustment of covariates (β = −1.401, p < 0.05). Serum DAO and LPS were both negatively associated with HGS in middle-aged and older males, with the significant interactions of GM in the decision tree model, and D-lactate showed a negative association with HGS in females. Therefore, intestinal permeability was associated with the loss of skeletal muscle strength in middle-aged and older adults, and serum DAO may be a novel predictor for the loss of skeletal muscle strength in middle-aged and older males. [ABSTRACT FROM AUTHOR]

Lactose intolerance (LIT) is one of the major causes of irritable bowel syndrome (IBS) spectrum complaints. Differences in inadequate lactose digestion are described as various LIT phenotypes with basically unknown pathophysiology. In LIT patients, we retrospectively assessed the effect of histamine intolerance (HIT) on expiratory hydrogen (H2) during H2 lactose breath tests. In a retrospective evaluation of charts from 402 LIT patients, 200 patients were identified as having only LIT. The other 202 LIT patients were found to additionally have diamine oxidase (DAO) values of <10 U/mL, which indicates histamine intolerance (HIT). To identify HIT, standardized questionnaires, low serum DAO values and responses to a histamine-reduced diet were used. Patients were separated into three diagnostic groups according to the result of H2 breath tests: (1) LIT, with an H2 increase of >20 parts per million (ppm), but a blood glucose (BG) increase of >20 mg/dL, (2) LIT with an H2 increase of 20 ppm in combination with a BG increase of <20 mg/dL, and (3) LIT with an exhaled H2 increase of <20 ppm and BG increase of <20 mg/dL. Pairwise comparison with the Kruskal Wallis test was used to compare the areas under the curve (AUC) of LIT and LIT with HIT patients. Exhaled H2 values were significantly higher in H2 > 20 ppm and BG < 20 mg/dL patients with LIT and HIT (p = 0.007). This diagnostic group also showed a significant higher number of patients (p = 0.012) and a significant higher number of patients with gastrointestinal (GI) symptoms during H2 breath tests (p < 0.001). Therefore, low serum DAO values, indicating HIT, influence results of lactose tolerance breath tests. [ABSTRACT FROM AUTHOR]

Background: Histamine Intolerance (HIT) is a multifaceted pseudoallergic disorder possibly due to defective histamine metabolism. Diamine oxidase (DAO) contributes to histamine degradation and can be measured in the serum. The role of DAO measurement in the diagnostic work-up of HIT still remains unclear, and conflicting results have been reported in the literature. Therefore, we aimed to evaluate the possible clinical usefulness and consistency of DAO value ranges as provided by the assay manufacturer and verify whether they could predict the response to treatment. Methods: We retrospectively analyzed 192 outpatients with HIT symptoms and measured serum DAO values at baseline. Patients were prescribed either with low-histamine diet and/or enzymatic supplementation according to symptom severity and re-evaluated six to eight months later. Patients were stratified into three groups according to DAO levels: <3 U/mL, 3–10 U/mL, and >10 U/mL. HIT severity was assessed on a scale of 1 to 5 before and after treatment. Results: A total of 146 patients completed the study. Gastrointestinal and cutaneous symptoms, often associated with headache, were more frequent in subjects with DAO < 10 U/mL. Symptom severity and DAO ranges were correlated. Patients with intermediate DAO levels (3–10 U/mL) showed a more complex clinical phenotype but also a more significant improvement in symptom severity (score reduction 50%, interquartile range (IQR) = 33–60%) when compared to patients with low DAO (40%, IQR = 20–60%; p = 0.045) or high DAO (33%, IQR = 0–50%; p < 0.001). Complex clinical phenotypes were also more frequent in patients with intermediate DAO levels. Conclusions: HIT is characterized by typical symptoms and low levels of DAO activity. Symptom severity was associated with the degree of DAO deficiency. Patients with DAO values between 3 and 10 U/mL show the best response to treatment (low-histamine diet and/or DAO supplementation). DAO value could arguably be considered as a predictor of clinical response to treatment. Prospective studies are needed to confirm these data. [ABSTRACT FROM AUTHOR]