Pharmacological Screening Identifies SHK242 and SHK277 as Novel Arginase Inhibitors with Efficacy against Allergen-Induced Airway Narrowing In Vitro and In Vivo.

Arginase is a potential target for asthma treatment. However, there are currently no arginase inhibitors available for clinical use. Here, a novel class of arginase inhibitors was synthesized, and their efficacy was pharmacologically evaluated. The reference compound 2(S)-amino-6-boronohexanoic acid (ABH) and >200 novel arginase inhibitors were tested for their ability to inhibit recombinant human arginase 1 and 2 in vitro. The most promising compounds were separated as enantiomers. Enantiomer pairs SHK242 and SHK243, and SHK277 and SHK278 were tested for functional efficacy by measuring their effect on allergen-induced airway narrowing in lung slices of ovalbumin-sensitized guinea pigs ex vivo. A guinea pig model of acute allergic asthma was used to examine the effect of the most efficacious enantiopure arginase inhibitors on allergen-induced airway hyper-responsiveness (AHR), early and late asthmatic reactions (EAR and LAR), and airway inflammation in vivo. The novel compounds were efficacious in inhibiting arginase 1 and 2 in vitro. The enantiopure SHK242 and SHK277 fully inhibited arginase activity, with IC50 values of 3.4 and 10.5 µM for arginase 1 and 2.9 and 4.0 µM for arginase 2, respectively. Treatment of slices with ABH or novel compounds resulted in decreased ovalbumin-induced airway narrowing compared with control, explained by increased local nitric oxide production in the airway. In vivo, ABH, SHK242, and SHK277 protected against allergen-induced EAR and LAR but not against AHR or lung inflammation. We have identified promising novel arginase inhibitors for the potential treatment of allergic asthma that were able to protect against allergen-induced early and late asthmatic reactions. SIGNIFICANCE STATEMENT: Arginase is a potential drug target for asthma treatment, but currently there are no arginase inhibitors available for clinical use. We have identified promising novel arginase inhibitors for the potential treatment of allergic asthma that were able to protect against allergen-induced early and late asthmatic reactions. Our new inhibitors show protective effects in reducing airway narrowing in response to allergens and reductions in the early and late asthmatic response.

Switching from infliximab innovator to biosimilar in patients with inflammatory bowel disease: a 12-month multicentre observational prospective cohort study.

BACKGROUND: Infliximab biosimilars have become available for treatment of inflammatory bowel disease (IBD). However, data showing long-term safety and effectiveness of biosimilars in IBD patients are limited. AIM: To study prospectively the switch from infliximab innovator to biosimilar in an IBD cohort with 12 months follow-up to evaluate safety and effectiveness. METHODS: Adult IBD patients from two hospitals treated with infliximab innovator (Remicade; Janssen Biotech,  Horsham ,  Pennsylvania, USA) were switched to infliximab biosimilar (Inflectra; Hospira, Lake Forest, Illinois, USA) as part of routine care, but in a controlled setting. Blood samples were taken just before the first, second, fourth and seventh infusion of biosimilar. Infliximab trough levels, antibodies-to-infliximab (ATI), CRP and ESR were measured and disease activity scores were calculated. RESULTS: Our cohort consisted of 133 IBD patients (64% CD, 36% UC). Before switching we found widely varying infliximab levels (median 3.5 µg/mL). ATI were detected in eight patients (6%). Most patients were in remission or had mild disease (CD: 82% UC: 90%). After switching to biosimilar, 35 patients (26%) discontinued therapy within 12 months, mostly due to subjective higher disease activity (9%) and adverse events (AE, 9.8%). AE included general malaise/fatigue (n = 7), arthralgia (n = 2), skin problems (n = 2) and infusion reactions (n = 2). No differences in IFX levels, CRP, and disease activity scores were found between the four time points (P ≥ .0917). CONCLUSIONS: We found no differences in drug levels and disease activity between infliximab innovator and biosimilar in our IBD cohort, indicating that biosimilars are safe and effective. The high proportions of discontinuers were mostly due to elective withdrawal or subjective disease worsening.

Functional bowel symptoms in a general Dutch population and associations with common stimulants.

BACKGROUND: Functional gastrointestinal symptoms are often felt to be related to the use of alcohol, coffee and smoking. METHODS: A random sample of 500 adults was interviewed by telephone about their gastrointestinal symptoms and the use of alcohol, coffee and smoking. Dyspepsia and irritable bowel syndrome (IBS) were defined using common, internationally used criteria. RESULTS: Of those invited, 85.4% agreed to participate (43.5% male). Of the participants 21.4% had gastrointestinal symptoms >6 times/last year, 13.8% had dyspepsia, and 5.8% had IBS, the latter being more common among women. Of the men, 83.9% reported alcohol consumption, 92.0% drank coffee, and 52.2% smoked. Of the women 62.4% drank alcohol, 88.1% drank coffee and 29.8% smoked. Use of alcohol or coffee was not related to dyspepsia. Current smokers had a 2.3-fold increased risk (P=0.02) and former smokers a 2.7 increased risk (P=0.009) for dyspepsia compared to never smokers. No association between IBS and use of alcohol, coffee or smoking could be demonstrated. CONCLUSIONS: The prevalence of dyspepsia (13.8%) and of IBS (5.8%) in a general Dutch adult population appears to be lower than are reported in other countries. Use of alcohol and coffee was not associated with functional bowel symptoms. Former and current smoking were strongly related to dyspepsia.

Effect of coffee on motor and sensory function of proximal stomach.

Some people attribute dyspeptic symptoms to drinking coffee, suggesting that coffee affects one or more functions of the proximal gastrointestinal tract. In a randomized controlled, cross-over, single-blinded study, the effects of coffee on gastric relaxation, gastric wall compliance and sensations, elicited by distension, were investigated in 10 healthy volunteers. Using the barostat technique, volume changes of an intragastric bag were recorded for 20 min after intragastric administration of 280 ml of coffee or water. Then, after deflation, the volume of the bag was increased stepwise every 3 min to assess gastric wall compliance and wall tension. At the end of every volume step, sensations (nausea, pain, and bloating) were scored. During the first 20 min after coffee administration, the volume change of the intragastric bag was larger than after water (P < 0.05). There were no differences in gastric wall compliance, wall tension, or symptom scores. In conclusions, coffee, in comparison with water, enhances the adaptive relaxation of the proximal stomach, but has no effect on its wall compliance, wall tension, or sensory function.

The effect of coffee on gastric emptying and oro-caecal transit time.

BACKGROUND: The consumption of coffee allegedly induces or aggravates gastrointestinal symptoms. In order to investigate the effect of coffee on gastrointestinal motility we studied the effect of coffee on gastric emptying and oro-caecal transit time. METHODS: In a randomised, controlled, cross-over study gastric emptying and oro-caecal transit time were studied in 12 healthy volunteers, using applied potential tomography and lactulose hydrogen breath test, respectively. After 1 day of coffee abstinence and an overnight fast, coffee or the control drink (water) was drunk and 10 min thereafter a liquid nutrient meal was ingested together with lactulose. During 150 min, recordings were made with applied potential tomography and breath samples were taken every 5 min. Lag-phase duration and gastric half-emptying time were determined by two blinded observers. RESULTS: The lag-phase duration after coffee (median 19.8 min, range 6-47 min) was not significantly different from that after water (median 19.3 min, range 11-37.5), nor was the gastric half-emptying time (median 75.7 min, range 56-157.6 vs. median 83.4 min, range 64. 6-148.4). Likewise, coffee had no significant effect on oro-caecal transit time (median 135 min, range 60-270 vs. median 140 min, range 55-270). No significant correlation between any of these parameters and mean daily coffee intake was found. CONCLUSIONS: Coffee does not affect gastric emptying of a liquid meal or small bowel transit.

Effect of coffee on gastro-oesophageal reflux in patients with reflux disease and healthy controls.

BACKGROUND: Many patients with gastro-oesophageal reflux disease (GORD) report that coffee aggravates their symptoms and doctors tend to discourage its use in GORD. OBJECTIVE: To assess the effect of coffee ingestion on gastro-oesophageal acid reflux. DESIGN: A randomized, controlled, crossover study. PARTICIPANTS: Seven GORD patients and eight healthy subjects. METHODS: After 1 day of coffee abstinence, participants underwent 24-h oesophageal pH and manometric monitoring. At well-defined times, they ingested either 280 ml of regular paper-filtered coffee or 280 ml of warm water. Coffee or water was drunk 1 h after breakfast, during lunch, 1 h after dinner and after an overnight fast Reflux and oesophageal motility parameters were assessed for the first hour after each coffee or water intake. RESULTS: Coffee had no effect on postprandial acid reflux time or number of reflux episodes, either in GORD patients or in healthy subjects. Coffee increased the percentage acid reflux time only when ingested in the fasting period in the GORD patients (median 2.6, range 0-19.3 versus median 0, range 0-8.3; P = 0.028), but not in the healthy subjects. No effect of coffee on postprandial lower oesophageal sphincter pressure (LOSP), patterns of LOSP associated with reflux episodes or oesophageal contractions was found. CONCLUSION: Coffee has no important effect on gastro-oesophageal acid reflux in GORD patients, and no effect at all in healthy subjects.

Coffee and gastrointestinal function: facts and fiction. A review.

BACKGROUND: Effects of coffee on the gastrointestinal system have been suggested by patients and the lay press, while doctors tend to discourage its consumption in some diseases. METHODS: The literature on the effects of coffee and caffeine on the gastrointestinal system is reviewed with emphasis on gastrointestinal function. RESULTS: Although often mentioned as a cause of dyspeptic symptoms, no association between coffee and dyspepsia is found. Heartburn is the most frequently reported symptom after coffee drinking. It is demonstrated that coffee promotes gastro-oesophageal reflux. Coffee stimulates gastrin release and gastric acid secretion, but studies on the effect on lower oesophageal sphincter pressure yield conflicting results. Coffee also prolongs the adaptive relaxation of the proximal stomach, suggesting that it might slow gastric emptying. However, other studies indicate that coffee does not affect gastric emptying or small bowel transit. Coffee induces cholecystokinin release and gallbladder contraction, which may explain why patients with symptomatic gallstones often avoid drinking coffee. Coffee increases rectosigmoid motor activity within 4 min after ingestion in some people. Its effects on the colon are found to be comparable to those of a 1000 kCal meal. Since coffee contains no calories, and its effects on the gastrointestinal tract cannot be ascribed to its volume load, acidity or osmolality, it must have pharmacological effects. Caffeine cannot solely account for these gastrointestinal effects. CONCLUSIONS: Coffee promotes gastro-oesophageal reflux, but is not associated with dyspepsia. Coffee stimulates gallbladder contraction and colonic motor activity.

After a decade of Helicobacter pylori in The Netherlands. A survey of the practice of the members of the Dutch Society of Gastroenterology.

BACKGROUND: Knowledge of Helicobacter pylori infection has grown rapidly during the last decade and management of its associated pathology has changed concordantly. METHODS: We surveyed the management of H. pylori infection among members of the Dutch Society of Gastroenterology in 1995 via a postal questionnaire. RESULTS: Almost all 226 respondents (response rate 54%) treated patients for H. pylori infection and the responses suggested that at least 0.1% of Dutch citizens were treated for H. pylori infection in 1995 by this group of specialists. 98% of the respondents treated the H. pylori infection in patients with duodenal ulcer, 91% in cases of gastric ulcer, 56% in cases of gastric lymphoma, 33% in cases of premalignant changes in gastric mucosal histology, 32% in cases of non-ulcer dyspepsia, and 30% in cases of chronic use of proton pump inhibitors. The main diagnostic methods used were histology (93%), urease test (60%), and culture (46%). Triple therapy was most commonly used (54%), followed by quadruple therapy (26%) and double therapy (13%). Follow-up detection of H. pylori was routinely done by 42% of the respondents, while 48% did so only when confirmation of eradication was considered clinically relevant. Most specialists did follow-up detection after 8-12 weeks. CONCLUSIONS: In 1995 most Dutch specialists treated H. pylori in patients with associated ulcer disease. There was no consensus on its role in other diseases. Diagnostic methods and treatment regimens for eradication differed widely.

DNA strand breaks in human leukocytes induced by chemotherapy and total body irradiation.

The occurrence of DNA strand breaks and/or DNA alkali-labile sites in peripheral blood leucocytes was demonstrated ex vivo in three patients during and after bone marrow ablative chemotherapy and total body irradiation (TBI) with use of fluorometric analysis of the DNA unwinding rate in alkaline solution (FADU assay). DNA damage was apparent after cyclophosphamide administration and after TBI, related to the amount of the applied dose. In vivo repair occurred within 24 hours, although not to pretreatment values. Demethoxydaunorubicin and busulfan at the dosages used did not induce measurable DNA strand breaks. The experiences described may be developed further to study ex vivo the occurrence of DNA lesions in patients during and after anticancer treatment. Such studies may be of value in comparing the DNA damaging potential of different chemotherapeutic or radiotherapeutic regimens and as a biological assessment of DNA damage after nuclear casualties in cases where the dose is greater than 1-2 Gy and measurement can be made within due time after the ionizing exposure.

Evidence for an antagonism between caffeine and adenosine in the human cardiovascular system.

A randomized, double-blind and placebo-controlled study was performed in 10 normotensive male subjects to analyze a possible antagonism between caffeine and adenosine with respect to their effects on the cardiovascular system in humans. Caffeine alone, 250 mg intravenously (i.v.), increased blood pressure by 9/12 mm Hg, and resulted in a fall of heart rate (HR) of 3 beats/min. Plasma epinephrine (E) rose by 114% after caffeine. Adenosine alone, in an increasing dose of 0.04-0.16 mg/kg/min, induced an increase in systolic blood pressure (SBP) (17 mm Hg), and HR (33 beats/min), a moderate fall in diastolic blood pressure (DBP) (-4 mm Hg), and no change of mean arterial pressure (MAP). At the highest adenosine infusion rate, forearm blood flow, skin temperature (ST), and transcutaneous oxygen tension were lowered, whereas plasma (nor)epinephrine was increased 227.2 and 215.9%, respectively. Adenosine infusion after caffeine induced comparable effects, but the fractional adenosine-induced changes of SBP, HR, plasma catecholamines, plasma renin activity (PRA), and aldosterone all were significantly reduced by previous administration of caffeine. Our results indicate an antagonism between caffeine and adenosine in humans, which may support the suggestion that some circulatory effects of caffeine are caused by an interaction with endogenous adenosine.