A conceptual framework: the early and late phases of skeletal muscle dysfunction in the acute respiratory distress syndrome

Patients with acute respiratory distress syndrome (ARDS) often develop severe diaphragmatic and limb skeletal muscle dysfunction. Impaired muscle function in ARDS is associated with increased mortality, increased duration of mechanical ventilation, and functional disability in survivors. In this review, we propose that muscle dysfunction in ARDS can be categorized into an early and a late phase. These early and late phases are based on the timing in relationship to lung injury and the underlying mechanisms. The early phase occurs temporally with the onset of lung injury, is driven by inflammation and disuse, and is marked predominantly by muscle atrophy from increased protein degradation. The ubiquitin-proteasome, autophagy, and calpain-caspase pathways have all been implicated in early-phase muscle dysfunction. Late-phase muscle weakness persists in many patients despite resolution of lung injury and cessation of ongoing acute inflammation-driven muscle atrophy. The clinical characteristics and mechanisms underlying late-phase muscle dysfunction do not involve the massive protein degradation and atrophy of the early phase and may reflect a failure of the musculoskeletal system to regain homeostatic balance. Owing to these underlying mechanistic differences, therapeutic interventions for treating muscle dysfunction in ARDS may differ during the early and late phases. Here, we review clinical and translational investigations of muscle dysfunction in ARDS, placing them in the conceptual framework of the early and late phases. We hypothesize that this conceptual model will aid in the design of future mechanistic and clinical investigations of the skeletal muscle system in ARDS and other critical illnesses

Lung injury-induced skeletal muscle wasting in aged mice is linked to alterations in long chain fatty acid metabolism

Older patients are more likely to acquire and die from acute respiratory distress syndrome (ARDS) and muscle weakness may be more clinically significant in older persons. Recent data implicate muscle ring finger protein 1 (MuRF1) in lung injury-induced skeletal muscle atrophy in young mice and identify an alternative role for MuRF1 in cardiac metabolism regulation through inhibition of fatty acid oxidation

A Metabolomic Endotype of Bioenergetic Dysfunction Predicts Mortality in Critically Ill Patients with Acute Respiratory Failure

Acute respiratory failure (ARF) requiring mechanical ventilation, a complicating factor in sepsis and other disorders, is associated with high morbidity and mortality. Despite its severity and prevalence, treatment options are limited. In light of accumulating evidence that mitochondrial abnormalities are common in ARF, here we applied broad spectrum quantitative and semiquantitative metabolomic analyses of serum from ARF patients to detect bioenergetic dysfunction and determine its association with survival. Plasma samples from surviving and non-surviving patients (N = 15/group) were taken at day 1 and day 3 after admission to the medical intensive care unit and, in survivors, at hospital discharge. Significant differences between survivors and non-survivors (ANOVA, 5% FDR) include bioenergetically relevant intermediates of redox cofactors nicotinamide adenine dinucleotide (NAD) and NAD phosphate (NADP), increased acyl-carnitines, bile acids, and decreased acyl-glycerophosphocholines. Many metabolites associated with poor outcomes are substrates of NAD(P)-dependent enzymatic processes, while alterations in NAD cofactors rely on bioavailability of dietary B-vitamins thiamine, riboflavin and pyridoxine. Changes in the efficiency of the nicotinamide-derived cofactors\u27 biosynthetic pathways also associate with alterations in glutathione-dependent drug metabolism characterized by substantial differences observed in the acetaminophen metabolome. Based on these findings, a four-feature model developed with semi-quantitative and quantitative metabolomic results predicted patient outcomes with high accuracy (AUROC = 0.91). Collectively, this metabolomic endotype points to a close association between mitochondrial and bioenergetic dysfunction and mortality in human ARF, thus pointing to new pharmacologic targets to reduce mortality in this condition

The sympathetic nervous system regulates skeletal muscle motor innervation and acetylcholine receptor stability

Aim: Symptoms of autonomic failure are frequently the presentation of advanced age and neurodegenerative diseases that impair adaptation to common physiologic stressors. The aim of this work was to examine the interaction between the sympathetic and motor nervous system, the involvement of the sympathetic nervous system (SNS) in neuromuscular junction (NMJ) presynaptic motor function, the stability of postsynaptic molecular organization, and the skeletal muscle composition and function. Methods: Since muscle weakness is a symptom of diseases characterized by autonomic dysfunction, we studied the impact of regional sympathetic ablation on muscle motor innervation by using transcriptome analysis, retrograde tracing of the sympathetic outflow to the skeletal muscle, confocal and electron microscopy, NMJ transmission by electrophysiological methods, protein analysis, and state of the art microsurgical techniques, in C57BL6, MuRF1KO and Thy-1 mice. Results: We found that the SNS regulates motor nerve synaptic vesicle release, skeletal muscle transcriptome, muscle force generated by motor nerve activity, axonal neurofilament phosphorylation, myelin thickness, and myofibre subtype composition and CSA. The SNS also modulates the levels of postsynaptic membrane acetylcholine receptor by regulating the Gα i2 -Hdac4-Myogenin-MuRF1pathway, which is prevented by the overexpression of the guanine nucleotide-binding protein Gα i2 (Q205L), a constitutively active mutant G protein subunit. Conclusion: The SNS regulates NMJ transmission, maintains optimal Gα i2 expression, and prevents any increase in Hdac4, myogenin, MuRF1, and miR-206. SNS ablation leads to upregulation of MuRF1, muscle atrophy, and downregulation of postsynaptic AChR. Our findings are relevant to clinical conditions characterized by progressive decline of sympathetic innervation, such as neurodegenerative diseases and aging.Fil: Rodrigues, Anna C. Zaia. Wake Forest School of Medicine; Estados UnidosFil: Messi, Maria Laura. Wake Forest School of Medicine; Estados UnidosFil: Wang, Zhong Min. Wake Forest School of Medicine; Estados UnidosFil: Abba, Martín Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Inmunológicas Básicas y Aplicadas; ArgentinaFil: Pereyra, Andrea Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Wake Forest School of Medicine; Estados UnidosFil: Birbrair, Alexander. Wake Forest School of Medicine; Estados UnidosFil: Zhang, Tan. Wake Forest School of Medicine; Estados UnidosFil: O´Meara, Meaghan. Wake Forest School of Medicine; Estados UnidosFil: Kwan, Ping. Wake Forest School of Medicine; Estados UnidosFil: Lopez, Elsa I. S.. Wake Forest School of Medicine; Estados UnidosFil: Willis, Monte S.. University of North Carolina; Estados UnidosFil: Mintz, Akiva. Wake Forest School of Medicine; Estados UnidosFil: Files, D. Clark. University of North Carolina; Estados UnidosFil: Furdui, Cristina. Wake Forest School of Medicine; Estados UnidosFil: Oppenheim, Ronald W.. Wake Forest School of Medicine; Estados UnidosFil: Delbono, Osvaldo. Wake Forest School of Medicine; Estados Unido

Therapeutic exercise attenuates neutrophilic lung injury and skeletal muscle wasting

Early mobilization of critically ill patients with the acute respiratory distress syndrome (ARDS) has emerged as a therapeutic strategy that improves patient outcomes, such as the duration of mechanical ventilation and muscle strength. Despite the apparent efficacy of early mobility programs, their use in clinical practice is limited outside of specialized centers and clinical trials. To evaluate the mechanisms underlying mobility therapy, we exercised acute lung injury (ALI) mice for 2 days after the instillation of lipopolysaccharides into their lungs. We found that a short duration of moderate intensity exercise in ALI mice attenuated muscle ring finger 1 (MuRF1)?mediated atrophy of the limb and respiratory muscles and improved limb muscle force generation. Exercise also limited the influx of neutrophils into the alveolar space through modulation of a coordinated systemic neutrophil chemokine response. Granulocyte colony-stimulating factor (G-CSF) concentrations were systemically reduced by exercise in ALI mice, and in vivo blockade of the G-CSF receptor recapitulated the lung exercise phenotype in ALI mice. Additionally, plasma G-CSF concentrations in humans with acute respiratory failure (ARF) undergoing early mobility therapy showed greater decrements over time compared to control ARF patients. Together, these data provide a mechanism whereby early mobility therapy attenuates muscle wasting and limits ongoing alveolar neutrophilia through modulation of systemic neutrophil chemokines in lung-injured mice and humans.Fil: Files, D. Clark. School Of Medicine; Estados UnidosFil: Liu, Chun. School Of Medicine; Estados UnidosFil: Pereyra, Andrea Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Wang, Zhong Min. University Wake Forest; Estados Unidos. School Of Medicine; Estados UnidosFil: Aggarwal, Neil. Johns Hopkins Asthma And Allergy Center; Estados UnidosFil: D´Alessio, Franco. Johns Hopkins Asthma And Allergy Center; Estados UnidosFil: Garibaldi, Brian T.. Johns Hopkins Asthma and Allergy Center; Estados UnidosFil: Mock, Jason R.. Johns Hopkins Asthma and Allergy Center; Estados UnidosFil: Singer, Benjamin D.. Johns Hopkins Asthma and Allergy Center; Estados UnidosFil: Feng, Xin. Wake Forest School of Medicine; Estados UnidosFil: Yammani, Raghunatha R.. Wake Forest School of Medicine; Estados UnidosFil: Zhang, Tan. Wake Forest School of Medicine; Estados UnidosFil: Lee, Amy L.. Wake Forest School of Medicine; Estados UnidosFil: Philpott, Sydney. Wake Forest School of Medicine; Estados UnidosFil: Lussier, Stephanie. Wake Forest School of Medicine; Estados UnidosFil: Purcell, Lina. Wake Forest School of Medicine; Estados UnidosFil: Chou, Jeff. Wake Forest School of Medicine; Estados UnidosFil: Seeds, Michael. Wake Forest School of Medicine; Estados UnidosFil: King, Landon S.. Johns Hopkins Asthma and Allergy Center; Estados UnidosFil: Morris, Peter E.. Wake Forest School of Medicine; Estados UnidosFil: Delbono, Osvaldo. School Of Medicine; Estados Unido

Validation of a Novel, Rapid Sepsis Diagnostic for Emergency Department Use

OBJECTIVES: To assess the in vitro IntelliSep test, a microfluidic assay that quantifies the state of immune activation by evaluating the biophysical properties of leukocytes, as a rapid diagnostic for sepsis. DESIGN: Prospective cohort study. SETTING: Five emergency departments (EDs) in Louisiana, Missouri, North Carolina, and Washington. PATIENTS: Adult patients presenting to the ED with signs (two of four Systemic Inflammatory Response Syndrome criteria, where one must be temperature or WBC count) or suspicion (provider-ordered culture) of infection. INTERVENTIONS: All patients underwent testing with the IntelliSep using ethylene diamine tetraacetic acid-anticoagulated whole blood followed by retrospective adjudication for sepsis by sepsis-3 criteria by a blinded panel of physicians. MEASUREMENTS AND MAIN RESULTS: Of 599 patients enrolled, 572 patients were included in the final analysis. The result of the IntelliSep test is reported as the IntelliSep Index (ISI), ranging from 0.1 to 10.0, divided into three interpretation bands for the risk of sepsis: band 1 (low) to band 3 (high). The median turnaround time for ISI results was 7.2 minutes. The ISI resulted band 1 in 252 (44.1%), band 2 in 160 (28.0%), and band 3 in 160 (28.0%). Sepsis occurred in 26.6% (152 of 572 patients). Sepsis prevalence was 11.1% (95% CI, 7.5-15.7%) in band 1, 28.1% (95% CI, 21.3-35.8%) in band 2, and 49.4% (95% CI, 41.4-57.4%) in band 3. The Positive Percent Agreement of band 1 was 81.6% and the Negative Percent Agreement of band 3 was 80.7%, with an area under the receiver operating characteristic curve of 0.74. Compared with band 1, band 3 correlated with adverse clinical outcomes, including mortality, and resource utilization. CONCLUSIONS: Increasing ISI interpretation band is associated with increasing probability of sepsis in patients presenting to the ED with suspected infection

The sympathetic nervous system regulates skeletal muscle motor innervation and acetylcholine receptor stability

Aim: Symptoms of autonomic failure are frequently the presentation of advanced age and neurodegenerative diseases that impair adaptation to common physiologic stressors. The aim of this work was to examine the interaction between the sympathetic and motor nervous system, the involvement of the sympathetic nervous system (SNS) in neuromuscular junction (NMJ) presynaptic motor function, the stability of postsynaptic molecular organization, and the skeletal muscle composition and function. Methods: Since muscle weakness is a symptom of diseases characterized by autonomic dysfunction, we studied the impact of regional sympathetic ablation on muscle motor innervation by using transcriptome analysis, retrograde tracing of the sympathetic outflow to the skeletal muscle, confocal and electron microscopy, NMJ transmission by electrophysiological methods, protein analysis, and state of the art microsurgical techniques, in C57BL6, MuRF1KO and Thy-1 mice. Results: We found that the SNS regulates motor nerve synaptic vesicle release, skeletal muscle transcriptome, muscle force generated by motor nerve activity, axonal neurofilament phosphorylation, myelin thickness, and myofibre subtype composition and CSA. The SNS also modulates the levels of postsynaptic membrane acetylcholine receptor by regulating the Gαi2 -Hdac4-Myogenin-MuRF1pathway, which is prevented by the overexpression of the guanine nucleotide-binding protein Gαi2 (Q205L), a constitutively active mutant G protein subunit. Conclusion: The SNS regulates NMJ transmission, maintains optimal Gαi2 expression, and prevents any increase in Hdac4, myogenin, MuRF1, and miR-206. SNS ablation leads to upregulation of MuRF1, muscle atrophy, and downregulation of postsynaptic AChR. Our findings are relevant to clinical conditions characterized by progressive decline of sympathetic innervation, such as neurodegenerative diseases and aging.Centro de Investigaciones Inmunológicas Básicas y Aplicada

Therapeutic exercise attenuates neutrophilic lung injury and skeletal muscle wasting

Early mobilization of critically ill patients with the acute respiratory distress syndrome (ARDS) has emerged as a therapeutic strategy that improves patient outcomes, such as the duration of mechanical ventilation and muscle strength. Despite the apparent efficacy of early mobility programs, their use in clinical practice is limited outside of specialized centers and clinical trials. To evaluate the mechanisms underlying mobility therapy, we exercised acute lung injury (ALI) mice for 2 days after the instillation of lipopolysaccharides into their lungs. We found that a short duration of moderate intensity exercise in ALI mice attenuated muscle ring finger 1 (MuRF1)–mediated atrophy of the limb and respiratory muscles and improved limb muscle force generation. Exercise also limited the influx of neutrophils into the alveolar space through modulation of a coordinated systemic neutrophil chemokine response. Granulocyte colony-stimulating factor (G-CSF) concentrations were systemically reduced by exercise in ALI mice, and in vivo blockade of the G-CSF receptor recapitulated the lung exercise phenotype in ALI mice. Additionally, plasma G-CSF concentrations in humans with acute respiratory failure (ARF) undergoing early mobility therapy showed greater decrements over time compared to control ARF patients. Together, these data provide a mechanism whereby early mobility therapy attenuates muscle wasting and limits ongoing alveolar neutrophilia through modulation of systemic neutrophil chemokines in lung-injured mice and humans.Facultad de Ciencias Médica

Comparison of test-negative and syndrome-negative controls in SARS-CoV-2 vaccine effectiveness evaluations for preventing COVID-19 hospitalizations in the United States

BackgroundTest-negative design (TND) studies have produced validated estimates of vaccine effectiveness (VE) for influenza vaccine studies. However, syndrome-negative controls have been proposed for differentiating bias and true estimates in VE evaluations for COVID-19. To understand the use of alternative control groups, we compared characteristics and VE estimates of syndrome-negative and test-negative VE controls.MethodsAdults hospitalized at 21 medical centers in 18 states March 11-August 31, 2021 were eligible for analysis. Case patients had symptomatic acute respiratory infection (ARI) and tested positive for SARS-CoV-2. Control groups were test-negative patients with ARI but negative SARS-CoV-2 testing, and syndrome-negative controls were without ARI and negative SARS-CoV-2 testing. Chi square and Wilcoxon rank sum tests were used to detect differences in baseline characteristics. VE against COVID-19 hospitalization was calculated using logistic regression comparing adjusted odds of prior mRNA vaccination between cases hospitalized with COVID-19 and each control group.Results5811 adults (2726 cases, 1696 test-negative controls, and 1389 syndrome-negative controls) were included. Control groups differed across characteristics including age, race/ethnicity, employment, previous hospitalizations, medical conditions, and immunosuppression. However, control-group-specific VE estimates were very similar. Among immunocompetent patients aged 18-64 years, VE was 93 % (95 % CI: 90-94) using syndrome-negative controls and 91 % (95 % CI: 88-93) using test-negative controls.ConclusionsDespite demographic and clinical differences between control groups, the use of either control group produced similar VE estimates across age groups and immunosuppression status. These findings support the use of test-negative controls and increase confidence in COVID-19 VE estimates produced by test-negative design studies

Efficacy and safety of two neutralising monoclonal antibody therapies, sotrovimab and BRII-196 plus BRII-198, for adults hospitalised with COVID-19 (TICO): a randomised controlled trial

BACKGROUND: We aimed to assess the efficacy and safety of two neutralising monoclonal antibody therapies (sotrovimab [Vir Biotechnology and GlaxoSmithKline] and BRII-196 plus BRII-198 [Brii Biosciences]) for adults admitted to hospital for COVID-19 (hereafter referred to as hospitalised) with COVID-19. METHODS: In this multinational, double-blind, randomised, placebo-controlled, clinical trial (Therapeutics for Inpatients with COVID-19 [TICO]), adults (aged ≥18 years) hospitalised with COVID-19 at 43 hospitals in the USA, Denmark, Switzerland, and Poland were recruited. Patients were eligible if they had laboratory-confirmed SARS-CoV-2 infection and COVID-19 symptoms for up to 12 days. Using a web-based application, participants were randomly assigned (2:1:2:1), stratified by trial site pharmacy, to sotrovimab 500 mg, matching placebo for sotrovimab, BRII-196 1000 mg plus BRII-198 1000 mg, or matching placebo for BRII-196 plus BRII-198, in addition to standard of care. Each study product was administered as a single dose given intravenously over 60 min. The concurrent placebo groups were pooled for analyses. The primary outcome was time to sustained clinical recovery, defined as discharge from the hospital to home and remaining at home for 14 consecutive days, up to day 90 after randomisation. Interim futility analyses were based on two seven-category ordinal outcome scales on day 5 that measured pulmonary status and extrapulmonary complications of COVID-19. The safety outcome was a composite of death, serious adverse events, incident organ failure, and serious coinfection up to day 90 after randomisation. Efficacy and safety outcomes were assessed in the modified intention-to-treat population, defined as all patients randomly assigned to treatment who started the study infusion. This study is registered with ClinicalTrials.gov, NCT04501978. FINDINGS: Between Dec 16, 2020, and March 1, 2021, 546 patients were enrolled and randomly assigned to sotrovimab (n=184), BRII-196 plus BRII-198 (n=183), or placebo (n=179), of whom 536 received part or all of their assigned study drug (sotrovimab n=182, BRII-196 plus BRII-198 n=176, or placebo n=178; median age of 60 years [IQR 50-72], 228 [43%] patients were female and 308 [57%] were male). At this point, enrolment was halted on the basis of the interim futility analysis. At day 5, neither the sotrovimab group nor the BRII-196 plus BRII-198 group had significantly higher odds of more favourable outcomes than the placebo group on either the pulmonary scale (adjusted odds ratio sotrovimab 1·07 [95% CI 0·74-1·56]; BRII-196 plus BRII-198 0·98 [95% CI 0·67-1·43]) or the pulmonary-plus complications scale (sotrovimab 1·08 [0·74-1·58]; BRII-196 plus BRII-198 1·00 [0·68-1·46]). By day 90, sustained clinical recovery was seen in 151 (85%) patients in the placebo group compared with 160 (88%) in the sotrovimab group (adjusted rate ratio 1·12 [95% CI 0·91-1·37]) and 155 (88%) in the BRII-196 plus BRII-198 group (1·08 [0·88-1·32]). The composite safety outcome up to day 90 was met by 48 (27%) patients in the placebo group, 42 (23%) in the sotrovimab group, and 45 (26%) in the BRII-196 plus BRII-198 group. 13 (7%) patients in the placebo group, 14 (8%) in the sotrovimab group, and 15 (9%) in the BRII-196 plus BRII-198 group died up to day 90. INTERPRETATION: Neither sotrovimab nor BRII-196 plus BRII-198 showed efficacy for improving clinical outcomes among adults hospitalised with COVID-19. FUNDING: US National Institutes of Health and Operation Warp Speed