Exercise is medicine in oncology: Engaging clinicians to help patients move through cancer.

Multiple organizations around the world have issued evidence-based exercise guidance for patients with cancer and cancer survivors. Recently, the American College of Sports Medicine has updated its exercise guidance for cancer prevention as well as for the prevention and treatment of a variety of cancer health-related outcomes (eg, fatigue, anxiety, depression, function, and quality of life). Despite these guidelines, the majority of people living with and beyond cancer are not regularly physically active. Among the reasons for this is a lack of clarity on the part of those who work in oncology clinical settings of their role in assessing, advising, and referring patients to exercise. The authors propose using the American College of Sports Medicine's Exercise Is Medicine initiative to address this practice gap. The simple proposal is for clinicians to assess, advise, and refer patients to either home-based or community-based exercise or for further evaluation and intervention in outpatient rehabilitation. To do this will require care coordination with appropriate professionals as well as change in the behaviors of clinicians, patients, and those who deliver the rehabilitation and exercise programming. Behavior change is one of many challenges to enacting the proposed practice changes. Other implementation challenges include capacity for triage and referral, the need for a program registry, costs and compensation, and workforce development. In conclusion, there is a call to action for key stakeholders to create the infrastructure and cultural adaptations needed so that all people living with and beyond cancer can be as active as is possible for them.

In vivo evolution of a Klebsiella pneumoniae capsule defect with wcaJ mutation promotes complement-mediated opsono-phagocytosis during recurrent infection.

BACKGROUND: Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp) bloodstream infections are associated with high mortality. We studied clinical bloodstream KPC-Kp isolates to investigate mechanisms of resistance to complement, a key host defense against bloodstream infection. METHODS: We tested growth of KPC-Kp isolates in human serum. In serial isolates from a single patient, we performed whole genome sequencing and tested for complement resistance and binding by mixing study, direct ELISA, flow cytometry, and electron microscopy. We utilized an isogenic deletion mutant in phagocytosis assays and an acute lung infection model. RESULTS: We found serum resistance in 16 of 59 (27%) KPC-Kp clinical bloodstream isolates. In five genetically-related bloodstream isolates from a single patient, we noted a loss-of-function mutation in the capsule biosynthesis gene, wcaJ. Disruption of wcaJ was associated with decreased polysaccharide capsule, resistance to complement-mediated killing, and surprisingly, increased binding of complement proteins. Furthermore, an isogenic wcaJ deletion mutant exhibited increased opsono-phagocytosis in vitro and impaired in vivo control in the lung after airspace macrophage depletion in mice. CONCLUSIONS: Loss of function in wcaJ led to increased complement resistance, complement binding, and opsono-phagocytosis, which may promote KPC-Kp persistence by enabling co-existence of increased bloodstream fitness and reduced tissue virulence.

Lung Epithelium Releases Growth Differentiation Factor 15 in Response to Pathogen-mediated Injury.

GDF15 (growth differentiation factor 15) is a stress cytokine with several proposed roles, including support of stress erythropoiesis. Higher circulating GDF15 levels are prognostic of mortality during acute respiratory distress syndrome, but the cellular sources and downstream effects of GDF15 during pathogen-mediated lung injury are unclear. We quantified GDF15 in lower respiratory tract biospecimens and plasma from patients with acute respiratory failure. Publicly available data from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were reanalyzed. We used mouse models of hemorrhagic acute lung injury mediated by Pseudomonas aeruginosa exoproducts in wild-type mice and mice genetically deficient for Gdf15 or its putative receptor, Gfral. In critically ill humans, plasma levels of GDF15 correlated with lower respiratory tract levels and were higher in nonsurvivors. SARS-CoV-2 infection induced GDF15 expression in human lung epithelium, and lower respiratory tract GDF15 levels were higher in coronavirus disease (COVID-19) nonsurvivors. In mice, intratracheal P. aeruginosa type II secretion system exoproducts were sufficient to induce airspace and plasma release of GDF15, which was attenuated with epithelial-specific deletion of Gdf15. Mice with global Gdf15 deficiency had decreased airspace hemorrhage, an attenuated cytokine profile, and an altered lung transcriptional profile during injury induced by P. aeruginosa type II secretion system exoproducts, which was not recapitulated in mice deficient for Gfral. Airspace GDF15 reconstitution did not significantly modulate key lung cytokine levels but increased circulating erythrocyte counts. Lung epithelium releases GDF15 during pathogen injury, which is associated with plasma levels in humans and mice and can increase erythrocyte counts in mice, suggesting a novel lung-blood communication pathway.

Anti-inflammatory roles of type I interferon signaling in the lung.

Excessive or persistent inflammation may have detrimental effects on lung structure and function. Currently, our understanding of conserved host mechanisms that control the inflammatory response remains incompletely understood. In this study, we investigated the role of type I interferon signaling in the inflammatory response against diverse clinically relevant stimuli. Using mice deficient in type I interferon signaling (IFNAR1-/-), we demonstrate that the absence of interferon signaling resulted in a robust and persistent inflammatory response against Pseudomonas aeruginosa, lipopolysaccharide, and chemotherapeutic agent bleomycin. The elevated inflammatory response in IFNAR1-/- mice was manifested as elevated myeloid cells, such as macrophages and neutrophils, in the bronchoalveolar lavage. The inflammatory cell response in the IFNAR1-/- mice persisted to 14 days and there is impaired recovery and fibrotic remodeling of the lung in IFNAR1-/- mice after bleomycin injury. In the Pseudomonas infection model, the elevated inflammatory cell response led to improved bacterial clearance in IFNAR1-/- mice, although there was similar lung injury and survival. We performed RNA sequencing of lung tissue in wild-type and IFNAR1-/- mice after LPS and bleomycin injury. Our unbiased analysis identified differentially expressed genes between IFNAR1-/- and wild-type mice, including previously unknown regulation of nucleotide-binding oligomerization domain (NOD)-like receptor signaling, retinoic acid-inducible gene-I (RIG-I) signaling, and necroptosis pathway by type I interferon signaling in both models. These data provide novel insights into the conserved anti-inflammatory mechanisms of the type I interferon signaling.NEW & NOTEWORTHY Type I interferons are known for their antiviral activities. In this study, we demonstrate a conserved anti-inflammatory role of type I interferon signaling against diverse stimuli in the lung. We show that exacerbated inflammatory response in the absence of type I interferon signaling has both acute and chronic consequences in the lung including structural changes.

BATF2 enhances proinflammatory cytokine responses in macrophages and improves early host defense against pulmonary Klebsiella pneumoniae infection.

Basic leucine zipper transcription factor ATF-like 2 (BATF2) is a transcription factor that is emerging as an important regulator of the innate immune system. BATF2 is among the top upregulated genes in human alveolar macrophages treated with LPS, but the signaling pathways that induce BATF2 expression in response to Gram-negative stimuli are incompletely understood. In addition, the role of BATF2 in the host response to pulmonary infection with a Gram-negative pathogen like Klebsiella pneumoniae (Kp) is not known. We show that induction of Batf2 gene expression in macrophages in response to Kp in vitro requires TRIF and type I interferon (IFN) signaling, but not MyD88 signaling. Analysis of the impact of BATF2 deficiency on macrophage effector functions in vitro showed that BATF2 does not directly impact macrophage phagocytic uptake and intracellular killing of Kp. However, BATF2 markedly enhanced macrophage proinflammatory gene expression and Kp-induced cytokine responses. In vivo, Batf2 gene expression was elevated in lung tissue of wild-type (WT) mice 24 h after pulmonary Kp infection, and Kp-infected BATF2-deficient (Batf2-/-) mice displayed an increase in bacterial burden in the lung, spleen, and liver compared with WT mice. WT and Batf2-/- mice showed similar recruitment of leukocytes following infection, but in line with in vitro observations, proinflammatory cytokine levels in the alveolar space were reduced in Batf2-/- mice. Altogether, these results suggest that BATF2 enhances proinflammatory cytokine responses in macrophages in response to Kp and contributes to the early host defense against pulmonary Kp infection.NEW & NOTEWORTHY This study investigates the signaling pathways that mediate induction of BATF2 expression downstream of TLR4 and also the impact of BATF2 on the host defense against pulmonary Kp infection. We demonstrate that Kp-induced upregulation of BATF2 in macrophages requires TRIF and type I IFN signaling. We also show that BATF2 enhances Kp-induced macrophage cytokine responses and that BATF2 contributes to the early host defense against pulmonary Kp infection.

Impact of enzymatic digestion on single cell suspension yield from peripheral human lung tissue.

An increasing number of translational investigations of lung biology rely on analyzing single cell suspensions obtained from human lungs. To obtain these single cell suspensions, human lungs from biopsies or research-consented organ donors must be subjected to mechanical and enzymatic digestion prior to analysis with either flow cytometry or single cell RNA sequencing. A variety of enzymes have been used to perform tissue digestion, each with potential limitations. To better understand the limitations of each enzymatic digestion protocol and to establish a framework for comparing studies across protocols, we performed five commonly published protocols in parallel from identical samples obtained from 6 human lungs. Following mechanical (gentleMACS™) and enzymatic digestion, we quantified cell count and viability using a Nexcelom Cellometer and determined cell phenotype using multiparameter spectral flow cytometry (Cytek™ Aurora). We found that all protocols were superior in cellular yield and viability when compared to mechanical digestion alone. Protocols high in dispase cleaved immune markers CD4, CD8, CD69, and CD103 and contributed to an increased monocyte to macrophage yield. Similarly, dispase led to a differential epithelial cell yield, with increased TSPN8+ and ITGA6+ epithelial cells and reduced CD66e+ cells. When compared to collagenase D, collagenase P protocols yielded increased AT1 and AT2 cells and decreased endothelial cells. These results provide a framework for selecting an enzymatic digestion protocol best suited to the scientific question and allow for comparison of studies using different protocols.

Serum metabolomic signatures of fatty acid oxidation defects differentiate host-response subphenotypes of acute respiratory distress syndrome.

BACKGROUND: Fatty acid oxidation (FAO) defects have been implicated in experimental models of acute lung injury and associated with poor outcomes in critical illness. In this study, we examined acylcarnitine profiles and 3-methylhistidine as markers of FAO defects and skeletal muscle catabolism, respectively, in patients with acute respiratory failure. We determined whether these metabolites were associated with host-response ARDS subphenotypes, inflammatory biomarkers, and clinical outcomes in acute respiratory failure. METHODS: In a nested case-control cohort study, we performed targeted analysis of serum metabolites of patients intubated for airway protection (airway controls), Class 1 (hypoinflammatory), and Class 2 (hyperinflammatory) ARDS patients (N = 50 per group) during early initiation of mechanical ventilation. Relative amounts were quantified by liquid chromatography high resolution mass spectrometry using isotope-labeled standards and analyzed with plasma biomarkers and clinical data. RESULTS: Of the acylcarnitines analyzed, octanoylcarnitine levels were twofold increased in Class 2 ARDS relative to Class 1 ARDS or airway controls (P = 0.0004 and < 0.0001, respectively) and was positively associated with Class 2 by quantile g-computation analysis (P = 0.004). In addition, acetylcarnitine and 3-methylhistidine were increased in Class 2 relative to Class 1 and positively correlated with inflammatory biomarkers. In all patients within the study with acute respiratory failure, increased 3-methylhistidine was observed in non-survivors at 30 days (P = 0.0018), while octanoylcarnitine was increased in patients requiring vasopressor support but not in non-survivors (P = 0.0001 and P = 0.28, respectively). CONCLUSIONS: This study demonstrates that increased levels of acetylcarnitine, octanoylcarnitine, and 3-methylhistidine distinguish Class 2 from Class 1 ARDS patients and airway controls. Octanoylcarnitine and 3-methylhistidine were associated with poor outcomes in patients with acute respiratory failure across the cohort independent of etiology or host-response subphenotype. These findings suggest a role for serum metabolites as biomarkers in ARDS and poor outcomes in critically ill patients early in the clinical course.

Plasma SARS-CoV-2 RNA Levels as a Biomarker of Lower Respiratory Tract SARS-CoV-2 Infection in Critically Ill Patients With COVID-19.

Plasma SARS-CoV-2 viral RNA (vRNA) levels are predictive of COVID-19 outcomes in hospitalized patients, but whether plasma vRNA reflects lower respiratory tract (LRT) vRNA levels is unclear. We compared plasma and LRT vRNA levels in serially collected samples from mechanically ventilated patients with COVID-19. LRT and plasma vRNA levels were strongly correlated at first sampling (n = 33, r = 0.83, P < 10-9) and then declined in parallel in available serial samples except in nonsurvivors who exhibited delayed vRNA clearance in LRT samples. Plasma vRNA measurement may offer a practical surrogate of LRT vRNA burden in critically ill patients, especially early after ICU admission.

Severe Acute Respiratory Syndrome Coronavirus 2 Viremia Is Associated With Coronavirus Disease 2019 Severity and Predicts Clinical Outcomes.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral RNA (vRNA) is detected in the bloodstream of some patients with coronavirus disease 2019 (COVID-19), but it is not clear whether this RNAemia reflects viremia (ie, virus particles) and how it relates to host immune responses and outcomes. METHODS: SARS-CoV-2 vRNA was quantified in plasma samples from observational cohorts of 51 COVID-19 patients including 9 outpatients, 19 hospitalized (non-intensive care unit [ICU]), and 23 ICU patients. vRNA levels were compared with cross-sectional indices of COVID-19 severity and prospective clinical outcomes. We used multiple imaging methods to visualize virions in plasma. RESULTS: SARS-CoV-2 vRNA was detected in plasma of 100%, 52.6%, and 11.1% of ICU, non-ICU, and outpatients, respectively. Virions were detected in plasma pellets using electron tomography and immunostaining. Plasma vRNA levels were significantly higher in ICU > non-ICU > outpatients (P < .0001); for inpatients, plasma vRNA levels were strongly associated with higher World Health Organization (WHO) score at admission (P = .01), maximum WHO score (P = .002), and discharge disposition (P = .004). A plasma vRNA level >6000 copies/mL was strongly associated with mortality (hazard ratio, 10.7). Levels of vRNA were significantly associated with several inflammatory biomarkers (P < .01) but not with plasma neutralizing antibody titers (P = .8). CONCLUSIONS: Visualization of virus particles in plasma indicates that SARS-CoV-2 RNAemia is due, at least in part, to viremia. The levels of SARS-CoV-2 RNAemia correlate strongly with disease severity, patient outcome, and specific inflammatory biomarkers but not with neutralizing antibody titers.

Finding Order in the Chaos: Outstanding Questions in Klebsiella pneumoniae Pathogenesis.

Klebsiella pneumoniae are Gram-negative facultative anaerobes that are found within host-associated commensal microbiomes, but they can also cause a wide range of infections that are often difficult to treat. These infections are caused by different pathotypes of K. pneumoniae, called either classical or hypervirulent strains. These two groups are genetically distinct, inhabit nonoverlapping geographies, and cause different types of harmful infections in humans. These distinct bacterial groups have also been found to interact differently with the host immune system. Initial innate immune defenses against K. pneumoniae infection include complement, macrophages, neutrophils, and monocytes; these defenses are primary strategies employed by the host to clear infections. K. pneumoniae pathogenesis depends upon the interactions between the microbe and each of these host defenses, and it is becoming increasingly apparent that bacterial genetic diversity impacts the outcomes of these interactions. Here, we highlight recent advances in our understanding of K. pneumoniae pathogenesis, with a focus on how bacterial evolution and diversity impact K. pneumoniae interactions with mammalian innate immune host defenses. We also discuss outstanding questions regarding how K. pneumoniae can frustrate normal immune responses, capitalize upon states of immunocompromise, and cause infections with high mortality.

Intractable Coronavirus Disease 2019 (COVID-19) and Prolonged Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Replication in a Chimeric Antigen Receptor-Modified T-Cell Therapy Recipient: A Case Study.

A chimeric antigen receptor-modified T-cell therapy recipient developed severe coronavirus disease 2019, intractable RNAemia, and viral replication lasting >2 months. Premortem endotracheal aspirate contained >2 × 1010 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA copies/mL and infectious virus. Deep sequencing revealed multiple sequence variants consistent with intrahost virus evolution. SARS-CoV-2 humoral and cell-mediated immunity were minimal. Prolonged transmission from immunosuppressed patients is possible.

Respiratory Tract Dysbiosis Is Associated with Worse Outcomes in Mechanically Ventilated Patients.

Rationale: Host inflammatory responses have been strongly associated with adverse outcomes in critically ill patients, but the biologic underpinnings of such heterogeneous responses have not been defined.Objectives: We examined whether respiratory tract microbiome profiles are associated with host inflammation and clinical outcomes of acute respiratory failure.Methods: We collected oral swabs, endotracheal aspirates (ETAs), and plasma samples from mechanically ventilated patients. We performed 16S ribosomal RNA gene sequencing to characterize upper and lower respiratory tract microbiota and classified patients into host-response subphenotypes on the basis of clinical variables and plasma biomarkers of innate immunity and inflammation. We derived diversity metrics and composition clusters with Dirichlet multinomial models and examined our data for associations with subphenotypes and clinical outcomes.Measurements and Main Results: Oral and ETA microbial communities from 301 mechanically ventilated subjects had substantial heterogeneity in α and ß diversity. Dirichlet multinomial models revealed a cluster with low α diversity and enrichment for pathogens (e.g., high Staphylococcus or Pseudomonadaceae relative abundance) in 35% of ETA samples, associated with a hyperinflammatory subphenotype, worse 30-day survival, and longer time to liberation from mechanical ventilation (adjusted P < 0.05), compared with patients with higher α diversity and relative abundance of typical oral microbiota. Patients with evidence of dysbiosis (low α diversity and low relative abundance of "protective" oral-origin commensal bacteria) in both oral and ETA samples (17%, combined dysbiosis) had significantly worse 30-day survival and longer time to liberation from mechanical ventilation than patients without dysbiosis (55%; adjusted P < 0.05).Conclusions: Respiratory tract dysbiosis may represent an important, modifiable contributor to patient-level heterogeneity in systemic inflammatory responses and clinical outcomes.

Increased Alternative Complement Pathway Function and Improved Survival during Critical Illness.

Rationale: Complement is crucial for host defense but may also drive dysregulated inflammation. There is limited understanding of alternative complement function, which can amplify all complement activity, during critical illness.Objectives: We examined the function and key components of the alternative complement pathway in a series of critically ill patients and in a mouse pneumonia model.Methods: Total classical (CH50) and alternative complement (AH50) function were quantified in serum from 321 prospectively enrolled critically ill patients and compared with clinical outcomes. Alternative pathway (AP) regulatory factors were quantified by ELISA (n = 181) and examined via transcriptomics data from external cohorts. Wild-type, Cfb-/-, and C3-/- mice were infected intratracheally with Klebsiella pneumoniae (KP) and assessed for extrapulmonary dissemination.Measurements and Main Results: AH50 greater than or equal to median, but not CH50 greater than or equal to median, was associated with decreased 30-day mortality (adjusted odds ratio [OR], 0.53 [95% confidence interval (CI), 0.31-0.91]), independent of chronic liver disease. One-year survival was improved in patients with AH50 greater than or equal to median (adjusted hazard ratio = 0.59 [95% CI, 0.41-0.87]). Patients with elevated AH50 had increased levels of AP factors B, H, and properdin, and fewer showed a "hyperinflammatory" subphenotype (OR, 0.30 [95% CI, 0.18-0.49]). Increased expression of proximal AP genes was associated with improved survival in two external cohorts. AH50 greater than or equal to median was associated with fewer bloodstream infections (OR, 0.67 [95% CI, 0.45-0.98). Conversely, depletion of AP factors, or AH50 less than median, impaired in vitro serum control of KP that was restored by adding healthy serum. Cfb-/- mice demonstrated increased extrapulmonary dissemination and serum inflammatory markers after intratracheal KP infection compared with wild type.Conclusions: Elevated AP function is associated with improved survival during critical illness, possibly because of enhanced immune capacity.

No evidence of hemoglobin damage by SARS-CoV-2 infection.

SARS-CoV-2 disease (COVID-19) has affected over 22 million patients worldwide as of August 2020. As the medical community seeks better understanding of the underlying pathophysiology of COVID-19, several theories have been proposed. One widely shared theory suggests that SARS-CoV-2 proteins directly interact with human hemoglobin (Hb) and facilitate removal of iron from the heme prosthetic group, leading to the loss of functional hemoglobin and accumulation of iron. Herein, we refute this theory. We compared clinical data from 21 critically ill COVID-19 patients to 21 non-COVID-19 ARDS patient controls, generating hemoglobin-oxygen dissociation curves from venous blood gases. This curve generated from the COVID-19 cohort matched the idealized oxygen-hemoglobin dissociation curve well (Pearson correlation, R2 = 0.97, P.

Host-Response Subphenotypes Offer Prognostic Enrichment in Patients With or at Risk for Acute Respiratory Distress Syndrome.

OBJECTIVES: Classification of patients with acute respiratory distress syndrome into hyper- and hypoinflammatory subphenotypes using plasma biomarkers may facilitate more effective targeted therapy. We examined whether established subphenotypes are present not only in patients with acute respiratory distress syndrome but also in patients at risk for acute respiratory distress syndrome (ARFA) and then assessed the prognostic information of baseline subphenotyping on the evolution of host-response biomarkers and clinical outcomes. DESIGN: Prospective, observational cohort study. SETTING: Medical ICU at a tertiary academic medical center. PATIENTS: Mechanically ventilated patients with acute respiratory distress syndrome or ARFA. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We performed longitudinal measurements of 10 plasma biomarkers of host injury and inflammation. We applied unsupervised latent class analysis methods utilizing baseline clinical and biomarker variables and demonstrated that two-class models (hyper- vs hypoinflammatory subphenotypes) offered improved fit compared with one-class models in both patients with acute respiratory distress syndrome and ARFA. Baseline assignment to the hyperinflammatory subphenotype (39/104 [38%] acute respiratory distress syndrome and 30/108 [28%] ARFA patients) was associated with higher severity of illness by Sequential Organ Failure Assessment scores and incidence of acute kidney injury in patients with acute respiratory distress syndrome, as well as higher 30-day mortality and longer duration of mechanical ventilation in ARFA patients (p < 0.0001). Hyperinflammatory patients exhibited persistent elevation of biomarkers of innate immunity for up to 2 weeks postintubation. CONCLUSIONS: Our results suggest that two distinct subphenotypes are present not only in patients with established acute respiratory distress syndrome but also in patients at risk for its development. Hyperinflammatory classification at baseline is associated with higher severity of illness, worse clinical outcomes, and trajectories of persistently elevated biomarkers of host injury and inflammation during acute critical illness compared with hypoinflammatory patients. Our findings provide strong rationale for examining treatment effect modifications by subphenotypes in randomized clinical trials to inform precision therapeutic approaches in critical care.