Determining if live bacteria or a viral mimetic can cause the release of EVs in the lung.

<p>Live bacterial model: Mice (n = 6 per group) were intranasally challenged with <i>Haemophilus influenzae</i> (1×10⁷ colony forming units serotype b) in sterile phosphate buffered saline (PBS). Mice were sacrificed and BALF samples were collected at 6, 24 and 72 hours. The samples were then centrifuged (900 g) to remove the white blood cells and then treated with vehicle (PBS) or ATP<i>γS</i> (10⁻³ M), incubated for 4 hours and analysed by ELISA. Data shown as mean +/− S.E.M. (A: IL-1β, B: TNFα). #  = P = 0.0206 (Mann-Whitney). Viral mimetic model: Mice (n = 6 per group) were challenged with vehicle (saline, approximately 25 µl per nostril) or the viral mimetic Poly I:C (0.6 mg/ml) under inhaled isoflurane. Mice were sacrificed and BALF samples were collected at 2, 6 and 24 hours. The samples were then centrifuged (900 g) to remove the white blood cells and then treated with vehicle (PBS) or ATP<i>γS</i> (10⁻³ M), incubated for 4 hours and analysed by ELISA. Data shown as mean +/− S.E.M. (C: IL-1β, D: TNFα).</p

Demonstration of the concept that a bacterial mimetic insult can cause EV release.

<p>THP-1 cells were treated with RPMI (vehicle) or LPS (0.1 µM) and incubated overnight and samples were collected and centrifuged to remove the cells. The _supernatants were collected and split into two equal fractions: non-ultracentrifuged (EV-rich – left side) and ultracentrifuged (EV-_{deficient – right side}). The samples were pre-treated with vehicle (DMSO, 0.1%, V/V) or P2X₇ antagonist (AZ 11645373; 10⁻⁷ M). Samples were incubated for one hour and then treated with vehicle (PBS) or exogenous ATP<i>γS</i> (10⁻³ M). The samples were then incubated for a further 4 hours prior to ELISA assessment for cytokines (A: IL-1β, B: IL-18, C: TNFα, D: MMP-9). The data is shown as mean +/− S.E.M.</p

Determining whether the ATP/P2X₇ axis is central to the exacerbation response <i>in vivo.</i>

<p>Mice (n = 8 per group) were challenged with the aerosolised vehicle of endotoxin-free saline or LPS (1 mg/ml) in Perspex chambers for 30 minutes. Four hours later the mice were intranasally dosed with saline (2 ml/kg) or ATPγs (0.001 mg/kg) whilst under light anaesthesia (4% isoflurane in oxygen). The mice received oral vehicle or P2X₇ inhibitor, A438079, 30 minutes prior to the ATP challenge, 4 hours after the challenge and 1 hour prior to cull. Twenty four hours after the LPS exposure the mice were culled and lavaged. IL-1β (A) and neutrophil (B) numbers were measured in the BALF. Data shown as mean +/− S.E.M. An unpaired T-test was used for the statistical analysis. *  = P = 0.0378 (Panel A); *  = P = 0.0162 (Panel B).</p

Determining if a bacterial mimetic (LPS) can cause the release of EVs in the lung – Signalling.

<p>Mice (n = 6 per group) were challenged with the aerosolised vehicle of endotoxin-free saline or LPS (1 mg/ml) in Perspex chambers for 30 minutes. Animals were sacrificed and BALF obtained 6 hours after challenge. The samples were then centrifuged (900 g) to remove the white blood cells and then pre-treated with inhibitors (P2X₇ antagonist A 438079 (10⁻⁶ M) or caspase-1 inhibitor VX 765 (10⁻⁷ M)) and incubated for 1 hour. Samples were then treated with vehicle (PBS) or ATP<i>γS</i> (10⁻³ M), and incubated for a further 4 hours and subsequent cytokine release was analysed by ELISA. Data shown as mean +/− S.E.M. (A: IL-1β, B: TNFα). *  = P = 0.0138 (One way ANOVA followed by a Bonferroni's Multiple Comparison test).</p

Determining if a bacterial mimetic (LPS) can cause the release of EVs in the lung – Cytokine release.

<p>Mice were challenged with the aerosolised vehicle of endotoxin-free saline or LPS (1 mg/ml) in Perspex chambers for 30 minutes. Animals were sacrificed and BALF obtained 6 hours after challenge. The samples were centrifuged (900 g) to remove the white blood cells and debris, and then treated with vehicle (PBS) or ATP<i>γS</i> (10⁻³ M), and incubated for a further 4 hours and subsequent cytokine release was analysed by ELISA. Data shown as mean +/− S.E.M. (A: IL-1β, B: IL-18, C: IL-1α).</p

Determining if a bacterial mimetic (LPS) can cause the release of EVs in the lung – Nanosight imaging.

<p>Mice were challenged with the aerosolised vehicle of endotoxin-free saline or LPS (1 mg/ml) in Perspex chambers for 30 minutes. Animals were sacrificed and BALF obtained 6 hours after challenge. The samples were then centrifuged (900 g) to remove the white blood cells and debris. The presence of EVs was imaged using Nanosight technology.</p

Demonstration that LPS-induced release of EVs can enhance IL-1β and neutrophil levels and change disease phenotype in model known to have increased levels of ATP.

<p>Mice (n = 8 per treatment group) were exposed to either room air (control) or CS (3R4F cigarettes) using a negative pressure system. Mice were subjected to 2 periods of CS exposure (500 ml/minute) per day (4 hours apart) for 3 consecutive days. On the morning of the third challenge day, the mice were exposed to aerosolised vehicle of endotoxin free saline or LPS (1 mg/ml) in Perspex chambers for 30 minutes. Animals were culled and BALF and lung tissue samples were collected 24 hours after LPS treatment. IL-1β levels were measured in the BALF and neutrophil numbers were determined in the BALF and lung tissue. In separate BALF samples collected from parallel smoke or LPS driven challenges ATP levels were measured (Panel A). Data shown as mean +/− S.E.M. (A: ATP #  = P = 0.0023, Mann-Whitney; B: IL-1β #  = P = 0.0009, Mann-Whitney; C: BALF neutrophil number, #  = P = 0.0431, Students T test; D: lung tissue neutrophil number; #  = P = 0.0006, Mann-Whitney).</p

Human translation data: exogenous ATP increases IL-1β/IL-18 level in samples collected from LPS challenged healthy subjects.

<p>Healthy subjects were challenged with inhaled LPS and BALF was collected 6(10⁻³ M) and incubated for 4 hours; cytokine release was analysed by ELISA. Panel A shows the paired IL-1β data. Panel B, C and D represents the levels of IL-1β, IL-18 and TNFα, respectively. Data shown as mean +/− S.E.M. Statistical analysis using a paired T-test.</p

Determining if a bacterial mimetic (LPS) can cause the release of EVs in the lung – Electron Microscopy.

<p>Mice were challenged with the aerosolised vehicle of endotoxin-free saline or LPS (1 mg/ml) in Perspex chambers for 30 minutes. Animals were sacrificed and BALF obtained 6 hours after challenge. The samples were then centrifuged (900 g) to remove the white blood cells and debris. The presence of EVs was imaged using EM (top panel – vehicle, middle panels – vehicle challenge, bottom panels – LPS challenge).</p

Repair of acute respiratory distress syndrome by stromal cell administration (REALIST): a structured study protocol for an open-label dose-escalation phase 1 trial followed by a randomised, triple-blind, allocation concealed, placebo-controlled phase 2 trial

Background: Mesenchymal stromal cells (MSCs) may be of benefit in ARDS due to immunomodulatory and reparative properties. This trial investigates a novel CD362 enriched umbilical cord derived MSC product (REALIST ORBCEL-C), produced to Good Manufacturing Practice standards, in patients with moderate to severe ARDS due to COVID-19 and ARDS due to other causes.Methods: Phase 1 is a multicentre open-label dose-escalation pilot trial. Patients will receive a single infusion of REALIST ORBCEL-C (100 × 106 cells, 200 × 106 cells or 400 × 106 cells) in a 3 + 3 design. Phase 2 is a multicentre randomised, triple blind, allocation concealed placebo-controlled trial. Two cohorts of patients, with ARDS due to COVID-19 or ARDS due to other causes, will be recruited and randomised 1:1 to receive either a single infusion of REALIST ORBCEL-C (400 × 106 cells or maximal tolerated dose in phase 1) or placebo. Planned recruitment to each cohort is 60 patients. The primary safety outcome is the incidence of serious adverse events. The primary efficacy outcome is oxygenation index at day 7. The trial will be reported according to the Consolidated Standards for Reporting Trials (CONSORT 2010) statement.Discussion: The development and manufacture of an advanced therapy medicinal product to Good Manufacturing Practice standards within NHS infrastructure are discussed, including challenges encountered during the early stages of trial set up. The rationale to include a separate cohort of patients with ARDS due to COVID-19 in phase 2 of the trial is outlined.Trial registration: ClinicalTrials.gov NCT03042143. Registered on 3 February 2017. EudraCT Number 2017-000584-33.</div