A Double-Blind Randomized Placebo-Controlled Phase 3 Trial of Tobramycin Inhalation Solution in Adults With Bronchiectasis With Pseudomonas aeruginosa Infection.

BACKGROUND: Few large-scale studies have demonstrated the efficacy of tobramycin nebulization in bronchiectasis. We evaluated the efficacy and safety of nebulized tobramycin inhalation solution (TIS) in adults with bronchiectasis with Pseudomonas aeruginosa infection. RESEARCH QUESTION: Can TIS effectively reduce sputum P aeruginosa density and improve the bronchiectasis-specific quality of life in patients with bronchiectasis with P aeruginosa infection? STUDY DESIGN AND METHODS: This was a phase 3, 16-week, multicenter, randomized, double-blind, placebo-controlled trial. Eligible adults with bronchiectasis were recruited from October 2018 to July 2021. On the basis of usual care, patients nebulized TIS (300 mg/5 mL twice daily) or normal saline (5 mL twice daily) via vibrating-mesh nebulizer. Treatment consisted of two cycles, each consisting of 28 days on-treatment and 28 days off-treatment. The coprimary end points included changes from baseline in P aeruginosa density and Quality-of-Life Bronchiectasis Respiratory Symptoms score on day 29. RESULTS: The modified intention-to-treat population consisted of 167 patients in the tobramycin group and 172 patients in the placebo group. Compared with placebo, TIS resulted in a significantly greater reduction in P aeruginosa density (adjusted mean difference, 1.74 log10 colony-forming units/g; 95% CI, 1.12-2.35; P < .001) and greater improvement in Quality-of-Life Bronchiectasis Respiratory Symptoms score (adjusted mean difference, 7.91; 95% CI, 5.72-10.11; P < .001) on day 29. Similar findings were observed on day 85. TIS resulted in a significant reduction in 24-h sputum volume and sputum purulence score on days 29, 57, and 85. More patients became culture negative for P aeruginosa in the tobramycin group than in the placebo group on day 29 (29.3% vs 10.6%). The incidence of adverse events and serious adverse events were comparable between the two groups. INTERPRETATION: TIS is an effective treatment option and has an acceptable safety profile in patients with bronchiectasis with P aeruginosa infection. TRIAL REGISTRATION: ClinicalTrials.gov; No. NCT03715322; URL: www. CLINICALTRIALS: gov.

A Low-Producing Haplotype of Interleukin-6 Disrupting CTCF Binding Is Protective against Severe COVID-19.

Interleukin6 (IL-6) is a key driver of hyperinflammation in COVID-19, and its level strongly correlates with disease progression. To investigate whether variability in COVID-19 severity partially results from differential IL-6 expression, functional single-nucleotide polymorphisms (SNPs) of IL-6 were determined in Chinese COVID-19 patients with mild or severe illness. An Asian-common IL-6 haplotype defined by promoter SNP rs1800796 and intronic SNPs rs1524107 and rs2066992 correlated with COVID-19 severity. Homozygote carriers of C-T-T variant haplotype were at lower risk of developing severe symptoms (odds ratio, 0.256; 95% confidence interval, 0.088 to 0.739; P = 0.007). This protective haplotype was associated with lower levels of IL-6 and its antisense long noncoding RNA IL-6-AS1 by cis-expression quantitative trait loci analysis. The differences in expression resulted from the disturbance of stimulus-dependent bidirectional transcription of the IL-6/IL-6-AS1 locus by the polymorphisms. The protective rs2066992-T allele disrupted a conserved CTCF-binding locus at the enhancer elements of IL-6-AS1, which transcribed antisense to IL-6 and induces IL-6 expression in inflammatory responses. As a result, carriers of the protective allele had significantly reduced IL-6-AS1 expression and attenuated IL-6 induction in response to acute inflammatory stimuli and viral infection. Intriguingly, this low-producing variant that is endemic to present-day Asia was found in early humans who had inhabited mainland Asia since ∼40,000 years ago but not in other ancient humans, such as Neanderthals and Denisovans. The present study suggests that an individual's IL-6 genotype underlies COVID-19 outcome and may be used to guide IL-6 blockade therapy in Asian patients. IMPORTANCE Overproduction of cytokine interleukin-6 (IL-6) is a hallmark of severe COVID-19 and is believed to play a critical role in exacerbating the excessive inflammatory response. Polymorphisms in IL-6 account for the variability of IL-6 expression and disparities in infectious diseases, but its contribution to the clinical presentation of COVID-19 has not been reported. Here, we investigated IL-6 polymorphisms in severe and mild cases of COVID-19 in a Chinese population. The variant haplotype C-T-T, represented by rs1800796, rs1524107, and rs2066992 at the IL-6 locus, was reduced in patients with severe illness; in contrast, carriers of the wild-type haplotype G-C-G had higher risk of severe illness. Mechanistically, the protective variant haplotype lost CTCF binding at the IL-6 intron and responded poorly to inflammatory stimuli, which may protect the carriers from hyperinflammation in response to acute SARS-CoV-2 infection. These results point out the possibility that IL-6 genotypes underlie the differential viral virulence during the outbreak of COVID-19. The risk loci we identified may serve as a genetic marker to screen high-risk COVID-19 patients.

Regulation of smooth muscle contractility by the epithelium in rat tracheas: role of prostaglandin E2 induced by the neurotransmitter acetylcholine.

BACKGROUND: Previous studies have suggested the involvement of epithelium in modulating the contractility of neighboring smooth muscle cells. However, the mechanism underlying epithelium-derived relaxation in airways remains largely unclear. This study aimed to investigate the mechanism underlying epithelium-dependent smooth muscle relaxation mediated by neurotransmitters. METHODS: The contractile tension of Sprague-Dawley (SD) rat tracheal rings were measured using a mechanical recording system. Intracellular Ca2+ level was measured using a Ca2+ fluorescent probe Fluo-3 AM, and the fluorescence signal was recorded by a laser scanning confocal imaging system. The prostaglandin E2 (PGE2) content was measured using an enzyme-linked immunosorbent assay kit. RESULTS: We observed that the neurotransmitter acetylcholine (ACh) restrained the electric field stimulation (EFS)-induced contraction in the intact but not epithelium-denuded rat tracheal rings. After inhibiting the muscarinic ACh receptor (mAChR) or cyclooxygenase (COX), a critical enzyme in prostaglandin synthesis, the relaxant effect of ACh was attenuated. Exogenous PGE2 showed a similar inhibitory effect on the EFS-evoked contraction of tracheal rings. Moreover, ACh triggered phospholipase C (PLC)-coupled Ca2+ release from intracellular Ca2+ stores and stimulated COX-dependent PGE2 production in primary cultured rat tracheal epithelial cells. CONCLUSIONS: Collectively, this study demonstrated that ACh induced rat tracheal smooth muscle relaxation by promoting PGE2 release from tracheal epithelium, which might provide valuable insights into the cross-talk among neurons, epithelial cells and neighboring smooth muscle cells in airways.