The urinary 5-hydroxyindole acetic acid and plasma nitric oxide levels in irritable bowel syndrome: a preliminary study

Nitric oxide in the mechanisms of inhibitory effects of sodium butyrate on colon contractions in a mouse model of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a multifactorial disorder, with altered intestinal motility, visceral hypersensitivity, and dysfunction of the gut-brain axis. The aim of our study was to analyze the role of nitric oxide (NO) in the inhibitory effects of sodium butyrate on spontaneous contractility of proximal colon in a mouse model of IBS. IBS was induced by intracolonic infusion of acetic acid in the early postnatal period. Spontaneous contractions of proximal colon segments were studied in isometric conditions. The amplitude and frequency of colon contractions were higher in the IBS group. Sodium butyrate exerted inhibitory effects on colon contractions, which were less pronounced in IBS group. NO donors decreased spontaneous colon contractility and prevented the inhibitory effects of sodium butyrate in control and IBS groups. Nitric oxide synthase (NOS) inhibition by L-NAME increased contractile activity more effective in the control group and decreased the inhibitory action of sodium butyrate. In IBS group, preliminary application of L-NAME did not prevent sodium butyrate action. Our data indicate that butyrate exerts its inhibitory effects on colon motility at least partially through activation of NO synthesis. In the IBS model group, the NO-dependent mechanisms were less effective probably due to downregulation of NOS.

Mathematical modeling of Ethiopia's energy demand by sectors and energy types, with forecasts for the next 30 years

Due to the scarcity of economic resources, it is vital to optimize everything so that the supply and demand lines intersect in an optimized quantity, with no shortage or surplus of a provided item or service. Energy supply contains both surplus and shortage, thus estimating the amount of projected energy demand is a key work that must be completed. The objective of this paper is generating a mathematical model based on the actual data for thirty years forecasting. To create a mathematical model using actual data from the last fifteen years, a model that can represent the past trend and be used for future forecasting. This study provides a general overview of Ethiopia's current energy requirement with different energy type as well as sector-specific energy demand and estimates for different economic growth scenarios up to 2052. This model was created using a linear regression polynomial fit through Origin graphic and analysis software, and an econometric model was also applied. GDP was utilized as an independent variable in the economic model to determine the trend of energy consumption. Another input-output model is also used for multilinear regression to evaluate the change of four variables, GDP, population growth, urbanization growth rate, and general inflation rate, which was quantitatively linked with total energy requirement using Weka software. The mathematical model developed through linear and multilinear regression has been validated by using a different assumption on GDP growth based on past growth rate as low, medium and high growth rate and using the mathematical formula to generate an energy demand trend that can be compared with the actual trend; as a result, all the mathematical model that are generated has been found to be valid for the purpose of the intended work. Based on the generated mathematical model and different GDP growth rate scenario as low, medium, business as usual (BAU) and high a future energy demand was forecasted up to 2052 for thirty years. The model's results can help energy planners ensure that the country's supply capacity keeps up with predicted energy demand growth.

Positive Correlation between nNOS and Stress-Activated Bowel Motility Is Confirmed by In Vivo HiBiT System

Neuronal nitric oxide synthase (nNOS) has various roles as a neurotransmitter. However, studies to date have produced insufficient data to fully support the correlation between nNOS and bowel motility. This study aimed to investigate the correlation between nNOS expression and gastrointestinal (GI) tract motility using a stress-induced neonatal maternal separation (NMS) mouse model. In this study, we generated a genetically modified mouse with the HiBiT sequence knock-in into the nNOS gene using CRISPR/Cas9 for analyzing accurate nNOS expression. nNOS expression was measured in the stomach, small intestine, large intestine, adrenal gland, and hypothalamus tissues after establishing the NMS model. The NMS model exhibited a significant increase in nNOS expression in large intestine, adrenal gland, and hypothalamus. Moreover, a significant positive correlation was observed between whole gastrointestinal transit time and the expression level of nNOS. We reasoned that NMS induced chronic stress and consequent nNOS activation in the hypothalamic-pituitary-adrenal (HPA) axis, and led to an excessive increase in intestinal motility in the lower GI tract. These results demonstrated that HiBiT is a sensitive and valuable tool for analyzing in vivo gene activation, and nNOS could be a biomarker of the HPA axis-linked lower intestinal tract dysfunction.

Potential role of fecal microbiota in patients with constipation

BACKGROUND

We evaluated the safety and efficacy of fecal microbiota transplantation (FMT) for chronic functional constipation (CFC) ineffectively treated by conventional constipation medication.

METHODS

Thirty-four patients with CFC underwent FMT treatment (three rounds, via gastroscopy). Clinical scales, including the Wexner constipation score as the main index of efficiency, were completed at baseline; after each treatment, and at 2 and 3 months of follow up. Secondary evaluation indices included the self-assessment of constipation symptoms, patient assessment constipation quality-of-life questionnaire, Bristol stool form scale, and Zung's self-rating depression and anxiety scales. Gastrointestinal motility, motilin, gastrin, nitric oxide (NO), and 5-hydroxytryptamine (5-HT) were assessed before and after treatment. Intestinal flora changes were assessed by 16S ribosomal ribonucleic acid (rRNA) sequencing.

RESULTS

There were no serious adverse reactions. The clinical cure rate was 73.5% (25/34), clinical remission rate was 14.7% (5/34), and the inefficiency rate was 11.8% (4/34). Clinical scale data indicated that the FMT treatment was effective. Furthermore, FMT treatment promoted intestinal peristalsis, increased gastrointestinal motility, and increased serum NO and 5-HT levels. The 16S rRNA sequencing data indicated that high abundances of Bacteroides, Klebsiella, Megamonas, Erysipelotrichaceae and Epulopiscium may be the cause of constipation, and high abundances of Prevotella, Acidaminococcus and Butyricimonas may be the main factors in curing constipation.

CONCLUSION

Treatment with FMT regulates the intestinal microflora and changes the abundance of CFC-associated bacterial flora to improve constipation.

Effects of vitamin D3 supplementation on clinical symptoms, quality of life, serum serotonin (5-hydroxytryptamine), 5-hydroxy-indole acetic acid, and ratio of 5-HIAA/5-HT in patients with diarrhea-predominant irritable bowel syndrome: A randomized clinical trial

Vitamin D deficiency, common in the population with irritable bowel syndrome (IBS), can induce the main factors that lead to IBS clinical symptoms, such as depression, anxiety, and inflammation. Serotonin (5-HT) plays an important role in the pathophysiology of IBS, and its production and secretion are increased from the lumen due to stress and inflammation. The aim of this study was to evaluate the effect of vitamin D3 supplementation on the pathogenesis of diarrhea-predominant IBS (IBS-D). Seventy-four IBS-D patients (age: 18-65 y) participated in a randomized, double-blind, placebo-controlled trial study from February 2017 to May 2018, at Rasoul-e-Akram Hospital, Tehran, Iran. Subjects were allocated into two groups receiving 50,000 IU/week of vitamin D3 or placebo for 9 weeks. IBS severity score system (IBS-SSS), IBS-quality of life questionnaire (QoL), hospital anxiety and depression Scale (HADs), visceral sensitivity index (VSI) and serum 25(OH) vitamin D3, serotonin, 5-hydroxy-indole acetic acid and ratio of 5-HIAA/5-HT were evaluated before and after the interventions. Symptoms severity, QoL, HADs-depression, and VSI score improved significantly in the vitamin D group as compared to the placebo group (P-values: <0.001, 0.049, 0.023, and 0.008; respectively). There were no significant differences in abdominal bloating, HADs-anxiety, serum 5-HT, 5-HIAA, and 5-HIAA/5-HT between the two groups at the end of the study. Based on our results, we recommend serum vitamin D be evaluated in the process of treatment of these patients to ameliorate symptoms and quality life of IBS-D patients with vitamin D deficiency and/or insufficiency.

Effect of nitrergic system on colonic motility in a rat model of irritable bowel syndrome

AIM

The aim of this study is to investigate whether nitric oxide (NO)-mediated colonic motility was altered in rat irritable bowel syndrome (IBS) model, using different isoforms of NO-synthase (NOS) inhibitors.

MATERIALS AND METHODS

The animal model of IBS-like visceral hypersensitivity was induced by intra-colonic infusion of 0.5% acetic acid (AA) in saline once daily from postnatal days 8 to 21. Control animals received saline instead of AA. Experiments were performed at the end of 8 weeks. Distal colon tissues were resected and direct effects of different NOS inhibitors; N-omega-nitro-L-arginine methyl ester hydrochloride, (L-NAME), ARL-17477 dihydrochloride hydrate (ARL 17477), N-[3-(Aminomethyl) phenyl] methyl]-ethanimidamidedihydrochloride (1400 W), and N5-(1-Iminoethyl)-L-ornithine dihydrochloride (L-NIO) were evaluated concentration-dependently in vitro tissue bath. Besides, morphology of both groups was assessed with hematoxylin and eosin (H and E) staining and the impact of NO antibodies was determined using the immunohistochemical method.

RESULTS

The mean pressure values of spontaneous contractions and KCL (80 mmol/L) responses of distal colonic segments were similar in normal and IBS rats. L-NAME and ARL-17477 significantly increased the mean pressure of spontaneous colonic contractions in normal rats versus own base values (P < 0.05), but this increase did not significantly different when compared to IBS rats. In H and E staining, there was no difference with regard to morphology between two groups. Neuronal NOS (nNOS) immunoreactivity was found to be significantly decreased in IBS when compared to control groups (P < 0.05).

CONCLUSION

L-NAME and ARL-17477 mediated mean pressure values were found to be slightly decreased in IBS rats. These findings may be related to a decrease in nNOS level in IBS.

Expression of inducible nitric oxide synthase in mast cells contributes to the regulation of inflammatory cytokines in irritable bowel syndrome with diarrhea

BACKGROUND

Nitric oxide (NO) and mast cells (MCs) are possibly involved in the development of irritable bowel syndrome (IBS), but details on their role and interactions still remain undetermined. We aimed to investigate the expression of inducible NO synthase (iNOS) in MCs of the colon of IBS with diarrhea (IBS-D), and elucidated a potential role of NO in the differential regulation of cytokines in MCs.

METHODS

Colonic mucosal biopsies of 19 IBS-D patients and 16 healthy controls were collected. The expression of tryptase and iNOS was investigated by immunohistochemistry, Western blotting, and real-time PCR. Effects of NO on the expression of cytokines in rat bone marrow MCs (BMMCs) were examined using a cytokine array by NG-nitro-l-arginine methyl ester (L-NAME) treatment.

KEY RESULTS

Immunohistochemistry for tryptase revealed an increase in number of MCs with extensive iNOS expression in the colonic mucosa of IBS-D. Tryptase, iNOS and interleukin (IL)-1β mRNA and protein levels were upregulated in IBS-D compared with healthy controls. Specifically, a positive correlation between tryptase and iNOS protein expression was observed in the colon of IBS-D (r = 0.667, p < 0.05). Supernatant from IBS-D increased iNOS expression in BMMCs. Antibody array showed that agrin, beta-nerve growth factor, fractalkine, granulocyte-macrophage colony-stimulating factor, IL-1β, IL-1R6, IL-13, leptin, tumor necrosis factor alpha were suppressed, and cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2α, CINC-3, monocyte chemotactic protein-1, matrix metalloproteinase-8 were strongly produced in L-NAME treated BMMCs, comparable to levels in the control group.

CONCLUSIONS & INFERENCES

Our findings provide new evidence that NO is able to regulate many cytokines in MCs that may be involved in the development of IBS.

Analytical approach to determining human biogenic amines and their metabolites using eVol microextraction in packed syringe coupled to liquid chromatography mass spectrometry method with hydrophilic interaction chromatography column

Analysis of biogenic amines (BAs) in different human samples provides insight into the mechanisms of various biological processes, including pathological conditions, and thus may be very important in diagnosing and monitoring several neurological disorders and cancerous tumors. In this work, we developed a simple and fast procedure using a digitally controlled microextraction in packed syringe (MEPS) coupled to liquid chromatography mass spectrometry (LC-MS) method for simultaneous determination of biogenic amines, their precursors and metabolites in human plasma and urine samples. The separation of 12 low molecular weight and hydrophilic molecules with a wide range of polarities was achieved with hydrophilic interaction chromatography (HILIC) column without derivatization step in 12 min. MEPS was implemented using the APS sorbent in semi-automated analytical syringe (eVol(®)) and small volume of urine and plasma samples, 5 0µL and 100 μL, respectively. We evaluated important parameters influencing MEPS efficiency, including stationary phase selection, sample pH and volume, number of extraction cycles, and washing and elution volumes. In optimized MEPS conditions, the analytes were eluted by 3 × 50 μL of methanol with 0.1% formic acid. The chromatographic separation of analytes was performed on XBridge Amide™ BEH analytical column (3.0mm × 100 mm, 3.5 µm) using gradient elution with mobile phase consisting of phase A: 10mM ammonium formate buffer in water pH 3.0 and phase B: 10mM ammonium formate buffer in acetonitrile pH 3.0. The LC-HILIC-MS method was validated and, in optimum conditions, presented good linearity in concentration range within 10-2000 ng/mL for all the analytes with a determination coefficient (r(2)) higher than 0.999 for plasma and urine samples. Method recovery ranged within 87.6-104.3% for plasma samples and 84.2-98.6% for urine samples. The developed method utilizing polar APS sorbent along with polar HILIC column was applied for simultaneous bioanalysis of trace amounts of polar endogenous biogenic amines in real human urine and plasma samples.

The role of oxidants and reactive nitrogen species in irritable bowel syndrome: a potential etiological explanation

Background

The aim of this study was to evaluate the plasma concentrations of malondialdehyde (MDA) and nitric oxide (NO) and the plasma activities of oxidant and antioxidant enzymes in patients with IBS.

Material/Methods

A total of 36 patients with IBS were included in the study. Thirty-five healthy subjects were selected to form the control group. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), xanthine oxidase (XO), adenosine deaminase (AD) activities, and malondialdehyde (MDA) and nitric oxide (NO) concentrations were studied in the serum samples of all patients and controls.

Results

Plasma XO and AD activities, and MDA and NO concentrations were significantly higher in IBS patients than in controls. The SOD, CAT, and GSH-Px activities in the serum of patients with IBS were significantly lower than that of controls.

Conclusions

These results suggest that lipid peroxidation and alterations in the oxidant-antioxidant enzymatic system may play a role in the pathogenesis of IBS. Increased lipid peroxidation in IBS may be related to an increase in NO level and XO activity and a decrease in antioxidant enzymes activities. In addition, increased AD activity may have a role in immunological changes of IBS patients.

Role of neuronal nitric oxide synthase in colonic distension-induced hyperalgesia in distal colon of neonatal maternal separated male rats

BACKGROUND

Nitric oxide (NO) is implicated in the pathogenesis of irritable bowel syndrome (IBS) but the underlying mechanism is unclear. Thus, the aim of the present study is to examine the role of NO synthase (NOS) expression in the distal colon of neonatal maternal separation (NMS) model rats employed in IBS studies.

METHODS

Male neonates of Sprague-Dawley rats were randomly assigned into NMS and normal control (N) groups. Rats of NMS group were subjected to 3 h daily maternal separation on postnatal day 2-21. Rats were administrated non-selective NOS inhibitor l-NAME (100 mg kg(-1) ), selective neuronal NOS (nNOS) inhibitor 7-NINA (10mgkg(-1) ), selective inducible NOS (iNOS) inhibitor, endothelial NOS (eNOS) inhibitor (10mgkg(-1) ) or Vehicle (Veh; distilled water) intraperitoneally 1h prior to the experiment for the test and control groups, respectively.

KEY RESULTS

The amount of NO was significantly higher in the NMS Veh rats compared with unseparated N rats. Western-blotting and real-time quantitative PCR studies showed that protein and mRNA expression of nNOS were higher in the NMS group than that in the N rats; whereas no significant change in iNOS and eNOS was found in either groups. Neonatal maternal separation Veh rats showed low pain threshold and increased electromyogram (EMG) activity in response to colonic distension stimuli. l-NAME and 7-Nitroindazole monosodium salt (7-NINA) increased pain threshold pressure and attenuated EMG activity in the NMS rats. In addition, l-NAME and 7-NINA substantially reduced oxidative marker malondialdehyde level in NMS rats.

CONCLUSIONS & INFERENCES

Neonatal maternal separation increased the NO generation by nNOS upregulation that interact with reactive oxygen species contributing to the visceral hypersensitivity in IBS.

Urinary excretion of 5-hydroxy-3-indoleacetic acid in dystimic/depressed, adult obese women: what correlations to hepatic steatosis?

The synthesis of serotonin at CNS level is influenced by diet. Moreover, insulin resistance is associated with lower serotonin levels. Visceral obesity, strictly linked to hepatic steatosis is specifically associated with mild to severe somatic affective-depressive symptom clusters. Previous data support the view that depression involves serotonergic systems, reflecting low levels of urinary 5- hydroxy-3-indoleacetic acid (5-HIAA). The 24-h urinary excretion of 5-HIAA was evaluated in 76 dystimic/depressed, obese/overweight females, divided into two groups, i.e., on a hyper-caloric diet, associated with a life style characterized by leisure time sedentary behavior (LTSB, 35 women), or on a normo-caloric diet, assisted by program-based strategies aimed at promoting physical activity participation (PAP, 41 women). Beck Depression Inventory (BDI) was carried out to score the severity of dystimia/depression. Anthropometric measures, metabolic indices, severity of hepatic steatosis at sonography and HOMA were studied. Urinary levels of 5-HIAA in controls and PAP groups were comparable with a great overlap, while in the LTSB group the urinary excretion of 5-HIAA was significantly reduced in respect to that of the PAP group and obviously compared to that of the control group, 3.4±1.4 mg/L versus 6.2±2.7 mg/L and 6.4±2.6 mg/L, respectively, ANOVA test, P= 0.001. Among metabolic indices, cholesterol, HDL-cholesterol, triglycerides and uric acid were not able to predict urinary concentrations of 5-HIAA, which were not associated with hepatic steatosis; vice versa, ferritin levels, and mainly HOMA values, were independent predictors of the urinary excretion of 5-HIAA (β=0.235 and 0.45, respectively). Dystimia/depression severity was negatively predicted by urinary 5-HIAA levels in the sense that the highest BDI values were forecast by the lowest values of urinary 5-HIAA (β= -0.72).The importance of measuring the 24-h urinary excretion of 5-HIAA in follow-ups could rely on a method simultaneously mirroring the well-being status, the adherence to physical activity, which leads to improved insulin sensitivity, and the eating habits acquired by dystimic/depressed overweight/obese patients. In contrast, the significance of the urinary 5-HIAA is reduced in evaluating the severity of hepatic steatosis, likely because it is a structured process.