American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Jul 2022
Rare and Common Variants in KIF15 Contribute to Genetic Risk of Idiopathic Pulmonary Fibrosis.
Rationale: Genetic studies of idiopathic pulmonary fibrosis (IPF) have improved our understanding of this disease, but not all causal loci have been identified. Objectives: To identify genes enriched with rare deleterious variants in IPF and familial pulmonary fibrosis. Methods: We performed gene burden analysis of whole-exome data, tested single variants for disease association, conducted KIF15 (kinesin family member 15) functional studies, and examined human lung single-cell RNA sequencing data. ⋯ Cell proliferation is dependent on KIF15 in the presence of an inhibitor of Eg5/KIF11, which has partially redundant function. KIF15 is expressed specifically in replicating human lung cells and shows diminished expression in replicating epithelial cells of patients with IPF. Conclusions: Both rare deleterious variants and common variants in KIF15 link a nontelomerase pathway of cell proliferation with IPF susceptibility.
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Am. J. Respir. Crit. Care Med. · Jul 2022
Renal Microcirculation and Function in a Pig Model of Hemorrhagic Shock Resuscitation with Norepinephrine.
Rationale: Norepinephrine (NE) is commonly used in combination with fluid during resuscitation of hemorrhagic shock, but its impact on kidney microcirculation, oxygenation, and function is still unknown in this setting. Objectives: During hemorrhagic shock resuscitation, does a combination of fluid and NE affect kidney oxygenation tension, kidney microcirculatory perfusion, and 48-hour kidney function, as compared with fluid alone? Methods: Hemorrhagic shock was induced in 24 pigs, and 8 pigs were included as a sham group. Resuscitation of hemorrhagic shock was performed, using a closed-loop device, either by fluid alone (0.9% NaCl; fluid group) or associated with the administration of NE at two doses (moderate dose: mean rate of 0.64 μg ⋅ kg-1 ⋅ min-1; high dose: mean rate of 1.57 μg ⋅ kg-1 ⋅ min-1) to obtain a target systolic arterial pressure of 80 to 90 mm Hg. ⋯ There were no histologic differences between animals resuscitated with fluid and those resuscitated with NE. Conclusions: In pigs with hemorrhagic shock, resuscitation with a combination of NE and fluid restored kidney microcirculation and oxygenation, as well as renal function, in a manner comparable to fluid resuscitation alone and without differences between the two NE doses. NE administration led to a fluid volume-sparing effect with subsequently less hemodilution.
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Am. J. Respir. Crit. Care Med. · Jul 2022
ReviewInternational Differences in the Frequency of COPD Exacerbations Reported in Three Clinical Trials.
Rationale: Exacerbations of chronic obstructive pulmonary disease (COPD) are an important endpoint in multinational clinical treatment trials, but the observed event rate is often lower than anticipated and appears to vary between countries. Objectives: We investigated whether systematic differences in national exacerbation rates might explain this observed variation. Methods: We reviewed data from three large multicenter international randomized trials conducted over an 18-year period with different designs and clinical severities of COPD, comparing bronchodilator and/or inhaled corticosteroids with bronchodilators alone and/or placebo. ⋯ Severe exacerbations showed a different rank order internationally. Conclusions: Countries contributing to COPD trials differ consistently in their reporting of healthcare-defined exacerbations. These differences help explain why large studies have been needed to show differences between treatments that decrease exacerbation risk.
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Am. J. Respir. Crit. Care Med. · Jul 2022
Randomized Controlled TrialArginine Therapy and Cardiopulmonary Hemodynamics in Hospitalized Children with Sickle Cell Anemia: A Prospective Double-Blinded Randomized Placebo-Controlled Trial.
Rationale: Acute changes in cardiopulmonary hemodynamics that include tricuspid regurgitant jet velocity (TRV) elevation measured by Doppler echocardiography are often encountered during sickle cell vasoocclusive pain and acute chest syndrome (ACS). Arginine and nitric oxide depletion develop in patients with these complications. Arginine administration may therefore improve nitric oxide bioavailability and potentiate pulmonary vasodilatation. ⋯ Significant differences in multiple indices of cardiopulmonary hemodynamics and mean N-terminal pro B-type brain natriuretic peptide were also noted after arginine therapy. Conclusions: Oral arginine supplementation improves cardiopulmonary hemodynamics during sickle cell disease vasoocclusive pain and ACS. Clinical trial registered with Pan African Clinical Trial Registry https://pactr.samrc.ac.za/Search.aspx (PACTR201611001864290).
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Am. J. Respir. Crit. Care Med. · Jul 2022
Response to Hypoxia and the Ensuing Dysregulation of Inflammation Impacts Mycobacterium tuberculosis Pathogenicity.
Rationale: Different Mycobacterium tuberculosis (Mtb) strains exhibit variable degrees of virulence in humans and animal models. Differing stress response strategies used by different strains of Mtb could influence virulence. Objectives: We compared the virulence of two strains of Mtb with use in animal model research: CDC1551 and Erdman. ⋯ Erdman induced higher concentrations of DosR regulon relative to CDC1551. The DosR regulon is the global regulator of response to hypoxia in Mtb and critical for its persistence in granulomas. Conclusions: Our results show that the response to hypoxia is a critical mediator of virulence determination in Mtb, with potential impacts on bacillary persistence, reactivation, and efficiency of therapeutics.