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Introduction and objectives Acute Respiratory Distress Syndrome (ARDS) is associated with increased pulmonary vascular permeability. In the lung, transient receptor potential vanilloid 4 (TRPV4), a Ca2+-permeable cation channel, is a known regulator of endothelial permeability and pulmonary oedema. Segmentally-instilled lipopolysaccharide (LPS) challenge was used as a surrogate injury model to investigate the effects of TRPV4 channel blockade on alveolar-septal barrier permeability. Methods Healthy participants were randomised 1:1 to receive 2 doses of GSK2798745, a potent and selective TRPV4 channel blocker, or placebo, 12 h apart. The first and second doses were administered orally, respectively, 2 h before and 10 h after LPS instillation; LPS was administered by bronchoscopy. Total protein (TP) and neutrophils, as markers of barrier permeability and inflammation, were measured in bronchoalveolar lavage (BAL) samples collected before and after LPS challenge. The primary endpoint was baseline adjusted TP concentration in BAL at 24 h after LPS challenge. A Bayesian framework was used to estimate the posterior probability of any percentage reduction (GSK2798745 relative to placebo). Results Forty-seven participants were dosed and 45 completed (22 on GSK2798745 and 23 on placebo). There was no significant effect of GSK2798745 on BAL TP or neutrophils (Table). Overall, GSK2798745 was safe and well tolerated. The study was terminated early after an interim analysis, based on 20 participants in each group; if the study had continued to completion, there was 95% probability of any percentage reduction in BAL TP after GSK2798745). Conclusion As expected, the dose regimen of GSK2798745 gave plasma levels predicted to provide ∼70–85% TRPV4 inhibition during the 24 h after LPS challenge. At that exposure, GSK2798745 did not affect segmental LPS-mediated elevation of BAL TP or neutrophils. This study does not support GSK2798745, at the exposures observed in this study, as a treatment for alveolar-septal barrier permeability in ARDS patients. ClinicalTrials.gov Identifier:NCT03511105

Background Acute Respiratory Distress Syndrome (ARDS) is associated with increased pulmonaryvascular permeability. In the lung, transient receptor potential vanilloid 4 (TRPV4), a Ca2+-permeable cation channel, is a regulator of endothelial permeability and pulmonary edema. We performed a Phase I, placebocontrolled, doubleblind, randomized, parallel group, proofofmechanism study to investigate the effects of TRPV4 channel blocker, GSK2798745, on pulmonaryvascular barrier permeability using a model of lipopolysaccharide (LPS)induced lung inflammation. Methods Healthy participants were randomized 1:1 to receive 2 single doses of GSK2798745 or placebo, 12 hours apart. Two hours after the first dose, participants underwent bronchoscopy and segmental LPS instillation. Total protein concentration and neutrophil counts were measured in bronchoalveolar lavage (BAL) samples collected before and 24 hours after LPS challenge, as markers of barrier permeability and inflammation, respectively. The primary endpoint was baseline adjusted total protein concentration in BAL at 24 hours after LPS challenge. A Bayesian framework was used to estimate the posterior probability of any percentage reduction (GSK2798745 relative to placebo). Safety endpoints included the incidence of adverse events (AEs), vital signs, 12-lead electrocardiogram, clinical laboratory and haematological evaluations, and spirometry. Results Forty-seven participants were dosed and 45 completed the study (22 on GSK2798745 and 23 on placebo). Overall, GSK2798745 was well tolerated. Small reductions in mean baseline adjusted BAL total protein (~ 9%) and neutrophils (~ 7%) in the LPS-challenged segment were observed in the GSK2798745 group compared with the placebo group; however, the reductions did not meet pre-specified success criteria of at least a 95% posterior probability that the percentage reduction in the mean 24hours post LPS BAL total protein level (GSK2798745 relative to placebo) exceeded zero. Median plasma concentrations of GSK2798745 were predicted to inhibit TRPV4 on lung vascular endothelial cells by ~ 7085% during the 24 hours after LPS challenge; median ureacorrected BAL concentrations of GSK2798745 were 3.0 to 8.7fold higher than those in plasma. Conclusions GSK2798745 did not affect segmental LPS-induced elevation of BAL total protein or neutrophils, despite blood and lung exposures that were predicted to be efficacious.

Background and Purpose Nasal sensory nerves play an important role in symptoms associated with rhinitis triggered by environmental stimuli. Here, we propose that TRPV1 is pivotal in nasal sensory nerve activation and assess the potential of SB-705498 as an intranasal therapy for rhinitis. Experimental Approach The inhibitory effect of SB-705498 on capsaicin-induced currents in guinea pig trigeminal ganglion cells innervating nasal mucosa was investigated using patch clamp electrophysiology. A guinea pig model of rhinitis was developed using intranasal challenge of capsaicin and hypertonic saline to elicit nasal secretory parasympathetic reflex responses, quantified using MRI. The inhibitory effect of SB-705498, duration of action and potency comparing oral versus intranasal route of administration were examined. Key Results SB-705498 concentration-dependently inhibited capsaicin-induced currents in isolated trigeminal ganglion cells (pIC50 7.2). In vivo, capsaicin ipsilateral nasal challenge (0.03–1 mM) elicited concentration-dependent increases in contralateral intranasal fluid secretion. Ten per cent hypertonic saline initiated a similar response. Atropine inhibited responses to either challenge. SB-705498 inhibited capsaicin-induced responses by ∼50% at 10 mg·kg−1 (oral), non-micronized 10 mg·mL−1 or 1 mg·mL−1 micronized SB-705498 (intranasal) suspension. Ten milligram per millilitre intranasal SB-705498, dosed 24 h prior to capsaicin challenge produced a 52% reduction in secretory response. SB-705498 (10 mg·mL−1, intranasal) inhibited 10% hypertonic saline responses by 70%. Conclusions and Implications The paper reports the development of a guinea pig model of rhinitis. SB-705498 inhibits capsaicin-induced trigeminal currents and capsaicin-induced contralateral nasal secretions via oral and intranasal routes; efficacy was optimized using particle-reduced SB-705498. We propose that TRPV1 is pivotal in initiating symptoms of rhinitis.

Purpose: Asthma is associated with reversible airway obstruction, leucocyte infiltration, airways hyperresponsiveness (AHR) and airways remodelling. Fluid accumulation causes pulmonary oedema contributing to airways obstruction. We examined the temporal relationship between the late asthmatic response (LAR) following allergen challenge of sensitised guinea-pigs and pulmonary oedema measured by magnetic resonance imaging (MRI). Materials and Methods: Ovalbumin (OVA) sensitised guinea-pigs received either a single OVA inhalation (acute) or nine OVA inhalations at 48 h intervals (chronic). Airways obstruction was measured as specific airways conductance (sGaw) by whole body plethysmography. AHR to inhaled histamine and bronchoalveolar lavage for leucocyte counts were measured 24 h after a single or the final chronic ovalbumin challenges. MRI was performed at intervals after OVA challenge and high intensity oedemic signals quantified. Results: Ovalbumin caused early bronchoconstriction, followed at 7 h by a LAR and at 24 h AHR and leucocyte influx. The bright intensity MRI oedema signal, peaking at 7 h, was significantly (P

We propose a generic method to report on gene expression based on the use of an antigen–antibody reporting system and visualization by MRI. This methodology was demonstrated using a truncated form of the H2Kk antigen, tH2Kk, as the nonendogenous antigen to be imaged. HeLa cells, transfected to express tH2Kk, exposed to tH2Kk antibodies conjugated to a superparamagnetic iron oxide particle, generated strong negative contrast compared to non-H2Kk expressing cells by MRI. T2 of the tH2Kk expressing cells was 57.6 ± 17.0 ms, compared to 424.0 ± 38.7 and 445.4 ± 47.2 ms for the mock transfected and nontransfected cells, respectively (P < 0.001). tH2Kk expression in the former cells was confirmed by flow cytometry, fluorescence, and electron microscopy. The methodology can be adapted to image in vivo other nonendogenous antigens in cells/tissues.

We propose a generic method to report on gene expression based on the use of an antigen-antibody reporting system and visualization by MRI. This methodology was demonstrated using a truncated form of the H2K(k) antigen, tH2K(k), as the nonendogenous antigen to be imaged. HeLa cells, transfected to express tH2K(k), exposed to tH2K(k) antibodies conjugated to a superparamagnetic iron oxide particle, generated strong negative contrast compared to non-H2K(k) expressing cells by MRI. T(2) of the tH2K(k) expressing cells was 57.6 +/- 17.0 ms, compared to 424.0 +/- 38.7 and 445.4 +/- 47.2 ms for the mock transfected and nontransfected cells, respectively (P0.001). tH2K(k) expression in the former cells was confirmed by flow cytometry, fluorescence, and electron microscopy. The methodology can be adapted to image in vivo other nonendogenous antigens in cells/tissues.