Inhibition of protease-ENaC signaling improves mucociliary function in cystic fibrosis airways

Rationale: In cystic fibrosis (CF) a reduction in airway surface liquid (ASL) height
compromises mucociliary clearance, favoring mucus plugging and chronic bacterial infection. Inhibitors of ENaC have therapeutic potential in CF airways to reduce the hyperstimulated sodium and fluid absorption to levels which can restore airways hydration.

Objectives: To determine whether a novel compound (QUB-TL1) designed to inhibit protease/ENaC signaling in CF airways restores ASL volume and mucociliary function.

Methods: Protease activity was measured using fluorogenic activity assays. Differentiated primary airway epithelial cell cultures (F508del homozygotes) were used to determined ENaC activity (Ussing chamber recordings), ASL height (confocal microscopy) and mucociliary function (by tracking the surface flow of apically applied microbeads). Cell toxicity was measured by LDH assay.

Measurements and Results: QUB-TL1 inhibits extracellularly-located CAPs, including prostasin, matriptase and furin, the activities of which are observed at excessive levels at the apical surface of CF airway epithelial cells (AECs). QUB-TL1-mediated CAPs inhibition results in diminished ENaC-mediated Na+ absorption in CF AECs due to internalization of a prominent pool of cleaved (active) ENaCγ from the cell surface. Importantly, diminished ENaC activity correlates with improved airway hydration status and mucociliary clearance. We further demonstrate QUB-TL1-mediated furin inhibition, which is in contrast to other serine protease inhibitors (camostat mesylate and aprotinin), affords protection against neutrophil elastase-mediated ENaC activation and Pseudomonas aeruginosa exotoxin A induced cell death.

Conclusions: QUB-TL1 corrects aberrant CAP activities providing a mechanism to delay or prevent the development of CF lung disease in a manner independent of CFTR mutation.

Healthcare Staff Experience of Providing End-of-Life Care to Children: A Mixed Method Review

Background: Staff who provide end-of-life care to children not only have to deal with their own sense of loss, but also that of bereaved families. There is a dearth of knowledge on how they cope with these challenges.
Aim: The aim of this review is to explore the experiences of health care professionals who provide end-of-life care to children in order to inform the development of interventions to support them, thereby improving the quality of paediatric care for both children and their families.
Data sources: Searches included CINAHL, MEDLINE, Web of Science, EMBASE, PsychINFO, and The Cochrane Library in June 2015, with no date restrictions. Additional literature was uncovered from searching reference lists of relevant studies, along with contacting experts in the field of paediatric palliative care.
Design: This was a systematic mixed studies review. Study selection, appraisal and data extraction were conducted by two independent researchers. Integrative thematic analysis was used to synthesise the data.
Results: The 16 qualitative, six quantitative, and eight mixed-method studies identified included healthcare professionals in a range of settings. Key themes identified rewards and challenges of providing end-of-life care to children, the impact on staff’s personal and professional lives, coping strategies, and key approaches to help support staff in their role.
Conclusions: Education focusing on the unique challenges of providing end-of-life care to children and the importance of self-care, along with timely multidisciplinary debriefing are key strategies for improving healthcare staffs’ experiences, and as such the quality of care they provide.