The Neutrophilic Response to Pseudomonas Damages the Airway Barrier, Promoting Infection by Klebsiella pneumoniae.

Pseudomonas aeruginosa and Klebsiella pneumoniae are two common gram-negative pathogens that are associated with bacterial pneumonia and can often be isolated from the same patient. We used a mixed-pathogen pneumonia infection model in which mice were infected with sublethal concentrations of P. aeruginosa and K. pneumoniae, resulting in significant lethality, outgrowth of both bacteria in the lung, and systemic dissemination of K. pneumoniae. Inflammation, induced by P. aeruginosa activation of Toll-like receptor 5, results in prolonged neutrophil recruitment to the lung and increased levels of neutrophil elastase in the airway, resulting in lung damage and epithelial barrier dysfunction. Live P. aeruginosa was not required to potentiate K. pneumoniae infection, and flagellin alone was sufficient to induce lethality when delivered along with Klebsiella. Prophylaxis with an anti-Toll-like receptor 5 antibody or Sivelestat, a neutrophil elastase inhibitor, reduced neutrophil influx, inflammation, and mortality. Furthermore, pathogen-specific monoclonal antibodies targeting P. aeruginosa or K. pneumoniae prevented the outgrowth of both bacteria and reduced host inflammation and lethality. These findings suggest that coinfection with P. aeruginosa may enable the outgrowth and dissemination of K. pneumoniae, and that a pathogen- or host-specific prophylactic approach targeting P. aeruginosa may prevent or limit the severity of such infections by reducing neutrophil-induced lung damage.

Engineering Caveolae-Targeted Lipid Nanoparticles To Deliver mRNA to the Lungs.

Efficacious use of therapeutic gene delivery via nanoparticles is hampered by the challenges associated with targeted delivery to tissues of interest. Systemic administration of lipid nanoparticle (LNP)-encapsulated mRNA leads to a protein expressed predominantly in the liver and spleen. Here, LNP encapsulating mRNA was covalently conjugated to an antibody, specifically binding plasmalemma vesicle-associated protein (PV1) as a means to target lung tissue. Systemic administration of PV1-targeted LNPs demonstrated significantly increased delivery of mRNA to the lungs and a 40-fold improvement in protein expression in the lungs, compared with control LNPs. We also investigated the effect of LNP size to determine optimal tissue distribution and transfection. Larger-size PV1-targeted LNPs not only have the elasticity to target the PV1 expressed in the caveolae but also enable robust mRNA expression in the lungs. Targeted delivery of mRNA to the lungs is a promising approach in the treatment of lung diseases.

Intravitreal Ziv-Aflibercept : Safety Analysis in Eyes Receiving More Than Ten Intravitreal Injections.

Purpose: To report the ocular and systemic adverse events in eyes receiving ≥10 intravitreal ziv-aflibercept (IVZ) injections.Methods: Medical records of patients who received ≥10 IVZ for various chorioretinal conditions with minimum follow up period of 12 months were retrospectively analysed. These eyes received standard dose of IVZ (1.25 mg/0.05 ml) on pro-re-nata (PRN) or treat and extend (T&E) protocol. The primary study outcome was ocular and systemic adverse events related to IVZ injections whereas secondary outcomes were change in best corrected visual acuity (BCVA) and central macular thickness (CMT) on optical coherence tomography (OCT) at last visit compared to baseline. Comparison of BCVA and CMT at baseline and final visit was done using paired t-test.Results: A total of 94 eyes which received a mean ± standard deviation (mean±SD = 14.4 ± 4.6) IVZ injections were studied. A total of 41 eyes were treatment naïve whereas 53 eyes received intravitreal injections in the past with last injection at least 3 months prior. Mean (±SD) follow up period was 26.7 ± 8.7 months. Ocular adverse events were limited with a case each of acute iridocyclitis, endophthalmitis, cataract progression and early epiretinal membrane formation. No systemic events were recorded within a month of IVZ injection. There was a significant improvement in BCVA (p = 0.001) and change in CMT (p = 0.001) at last visit.Conclusion: Ocular use of ziv-aflibercept is safe with limited ocular and systemic side effects. Multiple injections of IVZ can be used in various chorioretinal diseases over the long term.