American Journal of Respiratory Cell and Molecular Biology, Dec 1, 2018
Influenza viruses can result in significant lung injury with significant morbidity and mortality.... more Influenza viruses can result in significant lung injury with significant morbidity and mortality. In this study, we evaluated the impact of cigarette smoke (CS) exposure on the pulmonary fibroblastic response after influenza infection. We used a murine model in which animals were exposed to CS or room air and subsequently infected with H1N1 influenza virus. Inflammatory and fibrotic responses were measured at different time points after influenza infection. Primary fibroblasts were isolated from the lungs of mice and their characteristics were evaluated. Exposure to CS significantly increased the amount of collagen in the lungs of mice infected with influenza virus compared with the nonsmoking group at 30 days after infection. Furthermore, the presence of fibroblast-specific protein-positive cells increased in the lungs of influenza-infected mice that were exposed to CS compared with the infection-alone group. The smoking group also showed delays in weight recovery and higher cell counts in BAL fluid after infection. Active transforming growth factor b1 levels in BAL fluid increased in both groups; however, CS-exposed mice had a later surge in active transforming growth factor b1 (Day 24). Ex vivo cultures of lung-derived fibroblasts from CS-exposed mice with influenza infection showed rapid proliferation, increased expression of a-smooth muscle actin-stained stress fibers, and higher expression of growth factors compared with fibroblasts from room air-exposed lungs after infection. These results suggest that CS exposure changes the fibroblastic potential, leading to increased fibrosis after influenza infection.
medRxiv (Cold Spring Harbor Laboratory), Aug 4, 2020
Most currently approved strategies for the collection of saliva for COVID-19 diagnostics require ... more Most currently approved strategies for the collection of saliva for COVID-19 diagnostics require specialized tubes containing buffers promoted for the stabilization of SARS-CoV-2 RNA and virus inactivation. Yet many of these are expensive, in limited supply, and not necessarily validated specifically for viral RNA. While saliva is a promising sample type as it can be reliably self-collected for the sensitive detection of SARS-CoV-2, the expense and availability of these collection tubes are prohibitive to mass testing efforts. Therefore, we investigated the stability of SARS-CoV-2 RNA and infectious virus detection from saliva without supplementation. We tested RNA stability over extended periods of time (2-25 days) and at temperatures representing at-home storage and elevated temperatures which might be experienced when cold chain transport may be unavailable. We found SARS-CoV-2 RNA in saliva from infected individuals is stable at 4°C, room temperature (~19°C), and 30°C for prolonged periods and found limited evidence for viral replication in stored saliva samples. This work demonstrates that expensive saliva collection options involving RNA stabilization and virus inactivation buffers are not always needed, permitting the use of cheaper collection options. Affordable testing methods are urgently needed to meet current testing demands and for continued surveillance in reopening strategies. .
Severe respiratory viral infection induces procalcitonin in the absence of bacterial pneumonia
Thorax, Aug 21, 2020
IntroductionProcalcitonin expression is thought to be stimulated by bacteria and suppressed by vi... more IntroductionProcalcitonin expression is thought to be stimulated by bacteria and suppressed by viruses via interferon signalling. Consequently, during respiratory viral illness, clinicians often interpret elevated procalcitonin as evidence of bacterial coinfection, prompting antibiotic administration. We sought to evaluate the validity of this practice and the underlying assumption that viral infection inhibits procalcitonin synthesis.MethodsWe conducted a retrospective cohort study of patients hospitalised with pure viral infection (n=2075) versus bacterial coinfection (n=179). The ability of procalcitonin to distinguish these groups was assessed. In addition, procalcitonin and interferon gene expression were evaluated in murine and cellular models of influenza infection.ResultsPatients with bacterial coinfection had higher procalcitonin than those with pure viral infection, but also more severe disease and higher mortality (p<0.001). After matching for severity, the specificity of procalcitonin for bacterial coinfection dropped substantially, from 72% to 61%. In fact, receiver operating characteristic curve analysis showed that procalcitonin was a better indicator of multiple indices of severity (eg, organ failures and mortality) than of coinfection. Accordingly, patients with severe viral infection had elevated procalcitonin. In murine and cellular models of influenza infection, procalcitonin was also elevated despite bacteriologic sterility and correlated with markers of severity. Interferon signalling did not abrogate procalcitonin synthesis.DiscussionThese studies reveal that procalcitonin rises during pure viral infection in proportion to disease severity and is not suppressed by interferon signalling, in contrast to prior models of procalcitonin regulation. Applied clinically, our data suggest that procalcitonin represents a better indicator of disease severity than bacterial coinfection during viral respiratory infection.
The expense of saliva collection devices designed to stabilize severe acute respiratory syndrome ... more The expense of saliva collection devices designed to stabilize severe acute respiratory syndrome coronavirus 2 RNA is prohibitive to mass testing. However, virus RNA in nonsupplemented saliva is stable for extended periods and at elevated temperatures. Simple plastic tubes for saliva collection will make large-scale testing and continued surveillance easier.
medRxiv (Cold Spring Harbor Laboratory), Sep 3, 2020
Expanding testing capabilities is integral to managing the further spread of SARS-CoV-2 and devel... more Expanding testing capabilities is integral to managing the further spread of SARS-CoV-2 and developing reopening strategies, particularly in regards to identifying and isolating asymptomatic and pre-symptomatic individuals. Central to meeting testing demands are specimens that can be easily and reliably collected and laboratory capacity to rapidly ramp up to scale. We and others have demonstrated that high and consistent levels of SARS-CoV-2 RNA can be detected in saliva from COVID-19 inpatients, outpatients, and asymptomatic individuals. As saliva collection is non-invasive, extending this strategy to test pooled saliva samples from multiple individuals could thus provide a simple method to expand testing capacity.
Maternal respiratory SARS-CoV-2 infection in pregnancy is associated with a robust inflammatory response at the maternal-fetal interface
Med, May 1, 2021
Background Pregnant women are at increased risk for severe outcomes from coronavirus disease 2019... more Background Pregnant women are at increased risk for severe outcomes from coronavirus disease 2019 (COVID-19), but the pathophysiology underlying this increased morbidity and its potential effect on the developing fetus is not well understood. Methods We assessed placental histology, ACE2 expression, and viral and immune dynamics at the term placenta in pregnant women with and without respiratory severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Findings The majority (13 of 15) of placentas analyzed had no detectable viral RNA. ACE2 was detected by immunohistochemistry in syncytiotrophoblast cells of the normal placenta during early pregnancy but was rarely seen in healthy placentas at full term, suggesting that low ACE2 expression may protect the term placenta from viral infection. Using immortalized cell lines and primary isolated placental cells, we found that cytotrophoblasts, the trophoblast stem cells and precursors to syncytiotrophoblasts, rather than syncytiotrophoblasts or Hofbauer cells, are most vulnerable to SARS-CoV-2 infection in vitro. To better understand potential immune mechanisms shielding placental cells from infection in vivo, we performed bulk and single-cell transcriptomics analyses and found that the maternal-fetal interface of SARS-CoV-2-infected women exhibited robust immune responses, including increased activation of natural killer (NK) and T cells, increased expression of interferon-related genes, as well as markers associated with pregnancy complications such as preeclampsia. Conclusions SARS-CoV-2 infection in late pregnancy is associated with immune activation at the maternal-fetal interface even in the absence of detectable local viral invasion. Funding NIH (T32GM007205, F30HD093350, K23MH118999, R01AI157488, U01DA040588) and Fast Grant funding support from Emergent Ventures at the Mercatus Center.
Added Diagnostic Utility of Clinical Metagenomics for the Diagnosis of Pneumonia in Immunocompromised Adults
Chest, Apr 1, 2021
BACKGROUND In the evaluation of community-acquired pneumonia, 30-60% of cases remain undiagnosed,... more BACKGROUND In the evaluation of community-acquired pneumonia, 30-60% of cases remain undiagnosed, despite extensive conventional microbiologic testing (CMT). Clinical metagenomics (CM) is an unbiased pathogen detection method that can increase diagnostic yield. RESEARCH QUESTION Does adding clinical metagenomics to conventional microbiologic testing improve the diagnostic yield for pneumonia in immunocompromised adults? STUDY DESIGN AND METHODS We performed a non-interventional prospective study of immunocompromised adults with pneumonia who underwent bronchoscopy and bronchoalveolar lavage (BAL) over 2-years. CMT was performed per standard of care. A commercial CM test (Explify™ Respiratory) was performed on residual BAL fluid. Final microbiologic diagnoses were based on CMT vs. CMT + CM. Final clinical diagnoses were made based on laboratory results in conjunction with clinical and radiological findings and interpreted using CMT vs. CMT+CM. Hypothetical impact of CMT+CM on management and antimicrobial stewardship was also assessed. RESULTS A total of 30 immunocompromised adult patients (31 episodes of pneumonia) were included. Final microbiologic diagnoses were made in 11 cases (35%) using CMT and in 18 cases (58%) using CMT+CM. Bacterial pneumonia was diagnosed in 5 cases (16%) by CMT and in 13 cases (42%) by CMT+CM, fungal pneumonia in 6 cases (19%) by CMT and in 7 cases (23%) by CMT+CM and viral pneumonia in 2 cases (6%) by CMT and in 5 cases (16%) by CMT+CM. The hypothetical impact of CMT+CM on management was deemed probable in 1 case, possible in 8 and unlikely in 2 whereas the impact on antimicrobial stewardship was possible in 13 cases and unlikely in 7. Final clinical diagnoses were made in 20/31 cases (65%) based on CMT and in 23/31 cases (74%) based on CMT+CM. INTERPRETATION CMT+CM increased diagnostic yield in immunocompromised adults with pneumonia from 35% to 58%, mostly by detecting additional bacterial etiologies but was less useful for fungal pneumonia.
American Journal of Respiratory Cell and Molecular Biology, May 1, 2021
Community-acquired pneumonia is the most common type of pneumonia and remains a leading cause of ... more Community-acquired pneumonia is the most common type of pneumonia and remains a leading cause of morbidity and mortality worldwide. Although many different pathogens can contribute to pneumonia, Streptococcus pneumoniae is one of the common bacterial pathogens that underlie community-acquired pneumonia. RIPK3 (receptor-interacting protein kinase 3) is widely recognized as a key modulator of inflammation and cell death. To elucidate a potential role of RIPK3 in pneumonia, we examined plasma from healthy control subjects and patients positive for streptococcal pneumonia. In human studies, RIPK3 protein concentrations were significantly elevated and were identified as a potential plasma marker of pneumococcal pneumonia. To expand these findings, we used an in vivo murine model of pneumococcal pneumonia to demonstrate that RIPK3 deficiency leads to reduced bacterial clearance, severe pathological damage, and high mortality. Our results illustrated that RIPK3 forms a complex with RIPK1, MLKL (mixed-lineage kinase domain-like protein), and MCU (mitochondrial calcium uniporter) to induce mitochondrial calcium uptake and mitochondrial reactive oxygen species(mROS) production during S. pneumoniae infection. In macrophages, RIPK3 initiated necroptosis via the mROS-mediated mitochondrial permeability transition pore opening and NLRP3 inflammasome activation via the mROS–AKT pathway to protect against S. pneumoniae. In conclusion, our study demonstrated a mechanism by which RIPK3-initiated necroptosis is essential for host defense against S. pneumoniae.
Age-related dysregulation in the lipidome compromises the immune response to the severe acute res... more Age-related dysregulation in the lipidome compromises the immune response to the severe acute respiratory coronavirus (VIR5P.1140)
Seasonal influenza is a leading cause of disease worldwide, resulting in as many as 650 000 death... more Seasonal influenza is a leading cause of disease worldwide, resulting in as many as 650 000 deaths on a yearly basis [1]. Vaccination is the cornerstone of influenza prevention, but its efficacy is limited by the accuracy in predicting circulating strains. Epidemiological methods such as social distancing, the use of protective face masks and frequent hand washing are not routinely practiced in influenza prevention. In contrast, these methods have been widely applied during the COVID-19 outbreak. In this study, we investigated how this year's influenza season has been impacted during the COVID-19 pandemic.
Objective:While palliative care needs are assumed to improve during intensive care unit (ICU) car... more Objective:While palliative care needs are assumed to improve during intensive care unit (ICU) care, few empiric data exist on need trajectories or their impact on long-term outcomes. We aimed to describe trajectories of palliative care needs during ICU care and to determine if changes in needs over 1 week was associated with similar changes in psychological distress symptoms at 3 months.Design:Prospective cohort study.Setting:6 adult medical and surgical ICUs.Participants:Patients receiving mechanical ventilation for ≥2 days and their family members.Measurements and Main Results:The primary outcome was the 13-item Needs at the End-of-Life Screening Tool (NEST; total score range 0-130) completed by family members at baseline, 3, and 7 days. The Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), and Post-Traumatic Stress Scale (PTSS) were completed at baseline and 3 months. General linear models were used to estimate differences in distress symptoms by change in need (NEST improvement ≥10 points or not). 159 family members participated (median age 54.0 years, [IQR 44.0, 63.0], 125 [78.6%] female, 54 [34.0%] African American). At 7 days 53 (33%) a serious level of overall need and 35 (22%) ranked ≥1 individual need at the highest severity level. NEST scores improved ≥10 points in only 47 (30%). Median NEST scores were 22 (IQR 12, 40) at baseline and 19 (IQR 9, 37) at 7 days (change −2.0 [IQR −11.0, 5.0; p=0.12). There were no differences in PHQ-9, GAD-7, or PTSS change scores by change in NEST score (all p>0.15).Conclusions:Serious palliative care needs were common and persistent among families during ICU care. Improvement in needs was not associated with less psychological distress at 3 months. Serious needs may be commonly underrecognized in current practice.
Palliative care phenotypes among critically ill patients and family members: intensive care unit prospective cohort study
BMJ supportive & palliative care, Sep 27, 2022
ObjectiveBecause the heterogeneity of patients in intensive care units (ICUs) and family members ... more ObjectiveBecause the heterogeneity of patients in intensive care units (ICUs) and family members represents a challenge to palliative care delivery, we aimed to determine if distinct phenotypes of palliative care needs exist.MethodsProspective cohort study conducted among family members of adult patients undergoing mechanical ventilation in six medical and surgical ICUs. The primary outcome was palliative care need measured by the Needs at the End-of-Life Screening Tool (NEST, range from 0 (no need) to 130 (highest need)) completed 3 days after ICU admission. We also assessed quality of communication, clinician–family relationship and patient centredness of care. Latent class analysis of the NEST’s 13 items was used to identify groups with similar patterns of serious palliative care needs.ResultsAmong 257 family members, latent class analysis yielded a four-class model including complex communication needs (n=26, 10%; median NEST score 68.0), family spiritual and cultural needs (n=21, 8%; 40.0) and patient and family stress needs (n=43, 31%; 31.0), as well as a fourth group with fewer serious needs (n=167, 65%; 14.0). Interclass differences existed in quality of communication (median range 4.0–10.0, p<0.001), favourable clinician–family relationship (range 34.6%–98.2%, p<0.001) and both the patient centredness of care Eliciting Concerns (median range 4.0–5.0, p<0.001) and Decision-Making (median range 2.3–4.5, p<0.001) scales.ConclusionsFour novel phenotypes of palliative care need were identified among ICU family members with distinct differences in the severity of needs and perceived quality of the clinician–family interaction. Knowledge of need class may help to inform the development of more person-centred models of ICU-based palliative care.
Background: COVID-19 is caused by the severe acute respiratory syndrome virus SARS-CoV-2. It is w... more Background: COVID-19 is caused by the severe acute respiratory syndrome virus SARS-CoV-2. It is widely recognized as a respiratory pathogen, but neurologic complications can be the presenting manifestation in a subset of infected patients. Case presentation: We describe a 78-year old immunocompromised woman who presented with altered mental status after witnessed seizure-like activity at home. She was found to have SARS-CoV-2 infection and associated neuroinflammation. In this case, we undertake the first detailed analysis of cerebrospinal fluid (CSF) cytokines during COVID-19 infection and find a unique pattern of inflammation in CSF, but no evidence of viral neuroinvasion. Conclusion: Our findings suggest that neurologic symptoms such as encephalopathy and seizures may be the initial presentation of COVID-19. Central nervous system inflammation may associate with neurologic manifestations of disease.
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