Aberrant immune programming in neutrophils in cystic fibrosis

Cystic fibrosis is a life-shortening genetic disorder, caused by mutations in the gene that encodes cystic fibrosis transmembrane-conductance regulator, a cAMP-activated chloride and bicarbonate channel. Persistent neutrophilic inflammation is a major contributor to cystic fibrosis lung disease. However, how cystic fibrosis transmembrane-conductance regulator loss of function leads to excessive inflammation and its clinical sequela remains incompletely understood. In this study, neutrophils from F508del-CF and healthy control participants were compared for gene transcription. We found that cystic fibrosis circulating neutrophils have a prematurely primed basal state with significantly higher scores for activation, chemotaxis, immune signaling, and pattern recognition. Such an irregular basal state appeared not related to the blood environment and was also observed in neutrophils derived from the F508del-CF HL-60 cell line, indicating an innate characteristic of the phenotype. Lipopolysaccharides (LPS) stimulation drastically shifted the transcriptional landscape of healthy control neutrophils toward a robust immune response; however, cystic fibrosis neutrophils were immune-exhausted, reflected by abnormal cell aging and fate determination in gene programming. Moreover, cystic fibrosis sputum neutrophils differed significantly from cystic fibrosis circulating neutrophils in gene transcription with increased inflammatory response, aging, apoptosis, and necrosis, suggesting additional environmental influences on the neutrophils in cystic fibrosis lungs. Taken together, our data indicate that loss of cystic fibrosis transmembrane-conductance regulator function has intrinsic effects on neutrophil immune programming, leading to premature priming and dysregulated response to challenge.

Current Intensive Care Management of Thrombotic Thrombocytopenic Purpura: A Case Report and Updated Literature Review

Thrombotic thrombocytopenic purpura (TTP), caused by severely reduced activity of the von Willebrand factor-cleaving protease ADAMTS13, is a medical emergency with life-threatening complications and a 90% mortality rate if left untreated. It presents a diagnostic challenge given the multiorgan involvement of the cardiovascular, gastrointestinal, and central nervous systems. Furthermore, the well-known full pentad of fever, hemolytic anemia, bleeding associated with thrombocytopenia, neurological signs, and renal disease is often absent in patients with TTP. We present a 51-year-old male adult with TTP. We utilized the PLASMIC scoring system, which predicts the likelihood of ADAMST13 activity in adults with features of thrombotic microangiopathy and thrombocytopenia with high sensitivity and specificity. We further review the literature supporting the expert statement on ICU management of patients with TTP that plasma exchange (PEX) should be initiated within 6 hours of diagnosis with adjunctive glucocorticoids, rituximab, and caplacizumab. If PEX is unavailable, plasma infusion can be started while the patient awaits transfer to a center with PEX capabilities.

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

BACKGROUND

Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation.

METHODS

WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109.

FINDINGS

Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0-4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2-6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital.

INTERPRETATION

In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates.

FUNDING

European Society of Intensive Care Medicine, European Respiratory Society.

ABERRANT IMMUNE PROGRAMMING IN NEUTROPHILS IN CYSTIC FIBROSIS

Cystic fibrosis (CF) is a life-shortening genetic disorder, caused by mutations in the gene that encodes Cystic Fibrosis Transmembrane-conductance Regulator (CFTR), a cAMP-activated chloride and bicarbonate channel. Although multiple organ systems can be affected, CF lung disease claims the most morbidity and mortality due to chronic bacterial infection, persistent neutrophilic inflammation, and mucopurulent airway obstruction. Despite the clear predominance of neutrophils in these pathologies, how CFTR loss-of-function affects these cells per se remains incompletely understood. Here, we report the profiling and comparing of transcriptional signatures of peripheral blood neutrophils from CF participants and healthy human controls (HC) at the single-cell level. Circulating CF neutrophils had an aberrant basal state with significantly higher scores for activation, chemotaxis, immune signaling, and pattern recognition, suggesting that CF neutrophils in blood are prematurely primed. Such an abnormal basal state was also observed in neutrophils derived from an F508del-CF HL-60 cell line, indicating an innate characteristic of the phenotype. LPS stimulation drastically shifted the transcriptional landscape of HC circulating neutrophils towards a robust immune response, however, CF neutrophils were immune-exhausted. Moreover, CF blood neutrophils differed significantly from CF sputum neutrophils in gene programming with respect to neutrophil activation and aging, as well as inflammatory signaling, highlighting additional environmental influences on the neutrophils in CF lungs. Taken together, loss of CFTR function has intrinsic effects on neutrophil immune programming that leads to premature priming and dysregulated response to challenge.

Diagnosis of paediatric tuberculosis by optically detecting two virulence factors on extracellular vesicles in blood samples

Sensitive and specific blood-based assays for the detection of pulmonary and extrapulmonary tuberculosis would reduce mortality associated with missed diagnoses, particularly in children. Here we report a nanoparticle-enhanced immunoassay read by dark-field microscopy that detects two Mycobacterium tuberculosis virulence factors (the glycolipid lipoarabinomannan and its carrier protein) on the surface of circulating extracellular vesicles. In a cohort study of 147 hospitalized and severely immunosuppressed children living with HIV, the assay detected 58 of the 78 (74%) cases of paediatric tuberculosis, 48 of the 66 (73%) cases that were missed by microbiological assays, and 8 out of 10 (80%) cases undiagnosed during the study. It also distinguished tuberculosis from latent-tuberculosis infections in non-human primates. We adapted the assay to make it portable and operable by a smartphone. With further development, the assay may facilitate the detection of tuberculosis at the point of care, particularly in resource-limited settings.

Inflammatory pseudotumor mimicking chronic pulmonary embolism or pulmonary artery sarcoma: Report of five cases

Inflammatory pseudotumor (IPT), also known as plasma cell granuloma, is a rare lesion of unknown etiology that occurs in many organs, especially in the lung. Here we report five cases of IPT arising in pulmonary artery mimicking chronic thromboembolic disease, not previously documented in the literature. Those cases were identified at our institute among over 2500 pulmonary endarterectomy (PEA) specimens acquired from 2000 to 2017. The cohort included three men and two women with a median age of 41 years (range: 23–54). All patients presented with dyspnea and radiologic findings of pulmonary artery thromboembolism, some concerning for intimal sarcoma. The duration between disease onset and PEA ranged from 6 months to approximately 3 years. Histologically, all cases showed proliferation of spindle cells with marked inflammatory infiltrates composed predominantly of plasma cells, histiocytes, and small lymphocytes. Ancillary studies were performed in each case and ruled out other possibilities, such as sarcoma, lymphoma, plasmacytoma, IgG4‐related disease, and infection. IPT arising in pulmonary artery presenting clinically as acute or chronic thromboembolic disease is very unusual, in which clinical data, radiographic findings, and histopathologic features have to be integrated for reaching the proper diagnosis.

Mucosal Immunity in Cystic Fibrosis

The highly complex and variable genotype-phenotype relationships observed in cystic fibrosis (CF) have been an area of growing interest since the discovery of the CF transmembrane conductance regulator (CFTR) gene >30 y ago. The consistently observed excessive, yet ineffective, activation of both the innate and adaptive host immune systems and the establishment of chronic infections within the lung, leading to destruction and functional decline, remain the primary causes of morbidity and mortality in CF. The fact that both inflammation and pathogenic bacteria persist despite the introduction of modulator therapies targeting the defective protein, CFTR, highlights that we still have much to discover regarding mucosal immunity determinants in CF. Gene modifier studies have overwhelmingly implicated immune genes in the pulmonary phenotype of the disease. In this context, we aim to review recent advances in our understanding of the innate and adaptive immune systems in CF lung disease.

Inflammatory phenotype modulation in the respiratory tract and systemic circulation of e-cigarette users: a pilot study

Over 40 million people use e-cigarettes worldwide, but the impact of chronic e-cigarette use on health has not been adequately defined. In particular, effects of e-cigarette aerosol inhalation on inflammation and host defenses across the body are not fully understood. We conducted a longitudinal cohort pilot study to explore changes in the inflammatory state and monocyte function of e-cigarette users (n=20) versus healthy controls (n=13), and to evaluate effects of e-cigarette use reduction on the same. Saliva, sputum, and blood were obtained from e-cigarette users at baseline and after a 2-week intervention of decreased e-cigarette use. Overall, across 38 proteins quantified by multiplex, airway samples from e-cigarette users tended to have decreased levels of immunomodulatory proteins relative to healthy controls, while levels of cytokines, chemokines and growth factors in the circulation tended to be elevated. Specifically, e-cigarette users had lower levels of IL-1 receptor antagonist (IL-1Ra) in saliva (p<0.0001), with higher IL-1Ra and GRO levels in sputum (p<0.01 and p<0.05, respectively), and higher levels of both TNFβ (p<0.0001) and VEGF (p<0.0001) in plasma. Circulating monocytes from e-cigarette users had alterations in their inflammatory phenotype in response to reduced e-cigarette use, with blunted IL-8 and IL-6 release upon challenge with bacterial lipopolysaccharide (p<0.001 and p<0.05, respectively), suggesting a decreased ability to appropriately respond to bacterial infection. Based on these findings, chronic inhalation of e-cigarette aerosols alters the inflammatory state of the airways and systemic circulation, raising concern for the development of both inflammatory and infectious diseases in chronic users of e-cigarettes.

Liposome-mediated detection of SARS-CoV-2 RNA-positive extracellular vesicles in plasma

Plasma SARS-CoV-2 RNA may represent a viable diagnostic alternative to respiratory RNA levels, which rapidly decline after infection. Quantitative PCR with reverse transcription (RT-qPCR) reference assays exhibit poor performance with plasma, probably reflecting the dilution and degradation of viral RNA released into the circulation, but these issues could be addressed by analysing viral RNA packaged into extracellular vesicles. Here we describe an assay approach in which extracellular vesicles directly captured from plasma are fused with reagent-loaded liposomes to sensitively amplify and detect a SARS-CoV-2 gene target. This approach accurately identified patients with COVID-19, including challenging cases missed by RT-qPCR. SARS-CoV-2-positive extracellular vesicles were detected at day 1 post-infection, and plateaued from day 6 to the day 28 endpoint in a non-human primate model, while signal durations for 20-60 days were observed in young children. This nanotechnology approach uses a non-infectious sample and extends virus detection windows, offering a tool to support COVID-19 diagnosis in patients without SARS-CoV-2 RNA detectable in the respiratory tract.

An International Virtual COVID-19 Critical Care Training Forum for Healthcare Workers

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic resulted in redeployment of non-critical care-trained providers to intensive care units across the world. Concurrently, traditional venues for delivery of medical education faced major disruptions. The need for a virtual forum to fill knowledge gaps for healthcare workers caring for patients with coronavirus disease (COVID-19) was apparent in the early stages of the pandemic. Objective: The weekly, open-access COVID-19 Critical Care Training Forum (CCCTF) organized by the American Thoracic Society (ATS) provided a global audience access to timely content relevant to their learning needs. The goals of the forum were threefold: to aid healthcare providers in assessment and treatment of patients with COVID-19, to reduce provider anxiety, and to disseminate best practices. Methods: The first 13 ATS CCCTF sessions streamed live from April to July 2020. Structured debriefs followed each session and participant feedback was evaluated in planning of subsequent sessions. A second set of 14 sessions streamed from August to November 2020. Content experts were recruited from academic institutions across the United States. Results: As of July 2020, the ATS CCCTF had 2,494 live participants and 7,687 downloads for a total of 10,181 views. The majority of participants had both completed training (58.6%) and trained in critical care (53.8%). Physicians made up a majority (82.2%) of the audience that spanned the globe (61% were international attendees). Conclusion: We describe the rapid and successful implementation of an open-access medical education forum to address training and knowledge gaps among healthcare personnel caring for patients with COVID-19.

Compositional Differences in the Oral Microbiome of E-cigarette Users

Electronic (e)-cigarettes have been advocated as a safer alternative to conventional tobacco cigarettes. However, there is a paucity of data regarding the impact of e-cigarette aerosol deposition on the human oral microbiome, a key component in human health and disease. We aimed to fill this knowledge gap through a comparative analysis of the microbial community profiles from e-cigarette users and healthy controls [non-smokers/non-vapers (NSNV)]. Moreover, we sought to determine whether e-cigarette aerosol exposure from vaping induces persistent changes in the oral microbiome. To accomplish this, salivary and buccal mucosa samples were collected from e-cigarette users and NSNV controls, with additional oral samples collected from e-cigarette users after 2 weeks of decreased use. Total DNA was extracted from all samples and subjected to PCR amplification and sequencing of the V3-V4 hypervariable regions of the 16S rRNA gene. Our analysis revealed several prominent differences associated with vaping, specific to the sample type (i.e., saliva and buccal). In the saliva, e-cigarette users had a significantly higher alpha diversity, observed operational taxonomic units (OTUs) and Faith's phylogenetic diversity (PD) compared to NSNV controls, which declined with decreased vaping. The buccal mucosa swab samples were marked by a significant shift in beta diversity between e-cigarette users and NSNV controls. There were also significant differences in the relative abundance of several bacterial taxa, with a significant increase in Veillonella and Haemophilus in e-cigarette users. In addition, nasal swabs demonstrated a trend toward higher colonization rates with Staphylococcus aureus in e-cigarette users relative to controls (19 vs. 7.1%; p = n.s.). Overall, these data reveal several notable differences in the oral bacterial community composition and diversity in e-cigarette users as compared to NSNV controls.

Chronic E-Cigarette Aerosol Inhalation Alters the Immune State of the Lungs and Increases ACE2 Expression, Raising Concern for Altered Response and Susceptibility to SARS-CoV-2

Conventional smoking is known to both increase susceptibility to infection and drive inflammation within the lungs. Recently, smokers have been found to be at higher risk of developing severe forms of coronavirus disease 2019 (COVID-19). E-cigarette aerosol inhalation (vaping) has been associated with several inflammatory lung disorders, including the recent e-cigarette or vaping product use-associated lung injury (EVALI) epidemic, and recent studies have suggested that vaping alters host susceptibility to pathogens such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To assess the impact of vaping on lung inflammatory pathways, including the angiotensin-converting enzyme 2 (ACE2) receptor known to be involved in SARS-CoV-2 infection, mice were exposed to e-cigarette aerosols for 60 min daily for 1-6 months and underwent gene expression analysis. Hierarchical clustering revealed extensive gene expression changes occurred in the lungs of both inbred C57BL/6 mice and outbred CD1 mice, with 2,933 gene expression changes in C57BL/6 mice, and 2,818 gene expression changes in CD1 mice (>abs 1.25-fold change). Particularly, large reductions in IgA and CD4 were identified, indicating impairment of host responses to pathogens via reductions in immunoglobulins and CD4 T cells. CD177, facmr, tlr9, fcgr1, and ccr2 were also reduced, consistent with diminished host defenses via decreased neutrophils and/or monocytes in the lungs. Gene set enrichment (GSE) plots demonstrated upregulation of gene expression related to cell activation specifically in neutrophils. As neutrophils are a potential driver of acute lung injury in COVID-19, increased neutrophil activation in the lungs suggests that vapers are at higher risk of developing more severe forms of COVID-19. The receptor through which SARS-CoV-2 infects host cells, ACE2, was found to have moderate upregulation in mice exposed to unflavored vape pens, and further upregulation (six-fold) with JUUL mint aerosol exposure. No changes were found in mice exposed to unflavored Mod device-generated aerosols. These findings suggest that specific vaping devices and components of e-liquids have an effect on ACE2 expression, thus potentially increasing susceptibility to SARS-CoV-2. In addition, exposure to e-cigarette aerosols both with and without nicotine led to alterations in eicosanoid lipid profiles within the BAL. These data demonstrate that chronic, daily inhalation of e-cigarette aerosols fundamentally alters the inflammatory and immune state of the lungs. Thus, e-cigarette vapers may be at higher risk of developing infections and inflammatory disorders of the lungs.

E-cigarettes and health risks: more to the flavor than just the name

The growing interest in regulating flavored E-liquids must incorporate understanding of the "flavoring profile" of each E-liquid-which flavorings (flavoring chemicals) are present and at what concentrations not just focusing on the flavor on the label. We investigated the flavoring profile of 10 different flavored E-liquids. We assessed bronchial epithelial cell viability and apoptosis, phagocytosis of bacteria and apoptotic cells by macrophages after exposure to E-cigarette vapor extract (EVE). We validated our data in normal human bronchial epithelial cells (NHBE) and alveolar macrophages (AM) from healthy donors. We also assessed cytokine release and validated in the saliva from E-cigarette users. Increased necrosis/apoptosis (16.1-64.5% apoptosis) in 16HBE cells was flavor dependent, and NHBEs showed an increased susceptibility to flavors. In THP-1 differentiated macrophages phagocytosis was also flavor dependent, with AM also showing increased susceptibility to flavors. Further, Banana and Chocolate were shown to reduce surface expression of phagocytic target recognition receptors on alveolar macrophages. Banana and Chocolate increased IL-8 secretion by NHBE, whereas all 4 flavors reduced AM IL-1β secretion, which was also reduced in the saliva of E-cigarette users compared with healthy controls. Flavorant profiles of E-liquids varied from simple 2 compound mixtures to complex mixtures containing over a dozen flavorants. E-liquids with high benzene content, complex flavoring profiles, high chemical concentration had the greatest impacts. The Flavorant profile of E-liquids is key to disruption of the airway status quo by increasing bronchial epithelial cell apoptosis, causing alveolar macrophage phagocytic dysfunction, and altering airway cytokines.

BMI is Associated with Coronavirus Disease 2019 Intensive Care Unit Admission in African Americans

OBJECTIVE

Coronavirus disease 2019 (COVID-19) has disproportionately impacted the African American community. This study aims to identify the risk factors for severe COVID-19 disease in African American patients.

METHODS

This was a retrospective cross-sectional analysis of African American patients with COVID-19 treated between March 12 and April 9, 2020, at a single tertiary center. The primary outcome of interest was severe disease defined as those requiring intensive care unit (ICU) admission.

RESULTS

The study included 158 consecutive patients. The mean age was 57 years, and 61% were women. The mean (SD) of BMI was 33.2 (8.6) kg/m² . Overall, patients admitted to the ICU were older (62 vs. 55 years, P = 0.003) and had higher BMI (36.5 kg/m² vs. 31.9 kg/m² , P = 0.002). In unadjusted and adjusted analysis, the factors most associated with ICU admission in this sample were age (adjusted odds ratio [aOR]: 1.073; 95% CI: 1.033-1.114), BMI (aOR: 1.115; 95% CI: 1.052-1.182), and lung disease (aOR: 3.097; 95% CI: 1.137-8.437).

CONCLUSIONS

This study identified risk factors for severe disease in COVID-19, specifically in an African American population. Further inclusive research aimed at optimizing clinical care relevant to the African American population is critical to ensure an equitable response to COVID-19.

Metabolic Syndrome and COVID-19 Mortality Among Adult Black Patients in New Orleans

OBJECTIVE

Coronavirus disease 2019 (COVID-19) mortality is high in patients with hypertension, obesity, and diabetes. We examined the association between hypertension, obesity, and diabetes, individually and clustered as metabolic syndrome (MetS), and COVID-19 outcomes in patients hospitalized in New Orleans during the peak of the outbreak.

RESEARCH DESIGN AND METHODS

Data were collected from 287 consecutive patients with COVID-19 hospitalized at two hospitals in New Orleans, LA from 30 March to 5 April 2020. MetS was identified per World Health Organization criteria.

RESULTS

Among 287 patients (mean age 61.5 years; female, 56.8%; non-Hispanic black, 85.4%), MetS was present in 188 (66%). MetS was significantly associated with mortality (adjusted odds ratio [aOR] 3.42 [95% CI 1.52-7.69]), intensive care unit (ICU) (aOR 4.59 [CI 2.53-8.32]), invasive mechanical ventilation (IMV) (aOR 4.71 [CI 2.50-8.87]), and acute respiratory distress syndrome (ARDS) (aOR 4.70 [CI 2.25-9.82]) compared with non-MetS. Multivariable analyses of hypertension, obesity, and diabetes individually showed no association with mortality. Obesity was associated with ICU (aOR 2.18 [CI, 1.25-3.81]), ARDS (aOR 2.44 [CI 1.28-4.65]), and IMV (aOR 2.36 [CI 1.33-4.21]). Diabetes was associated with ICU (aOR 2.22 [CI 1.24-3.98]) and IMV (aOR 2.12 [CI 1.16-3.89]). Hypertension was not significantly associated with any outcome. Inflammatory biomarkers associated with MetS, CRP, and lactate dehydrogenase (LDH) were associated with mortality (CRP [aOR 3.66] [CI 1.22-10.97] and LDH [aOR 3.49] [CI 1.78-6.83]).

CONCLUSIONS

In predominantly black patients hospitalized for COVID-19, the clustering of hypertension, obesity, and diabetes as MetS increased the odds of mortality compared with these comorbidities individually.

E-cigarette use increases susceptibility to bacterial infection by impairment of human neutrophil chemotaxis, phagocytosis, and NET formation

E-cigarettes are portrayed as safer relative to conventional tobacco. However, burgeoning evidence suggests that E-cigarettes may adversely affect host defenses. However, the precise mechanisms by which E-cigarette vapor alters innate immune cell function have not been fully elucidated. We determined the effects of E-cigarette exposure on the function and responses to infectious challenge of the most abundant innate immune cell, the neutrophil, using isolated human neutrophils and a mouse model of gram-negative infection. Our results revealed that human neutrophils exposed to E-cigarette vapor had 4.2-fold reductions in chemotaxis toward the bacterial cell-well component f-Met-Leu-Phe (P < 0.001). F-actin polarization and membrane fluidity were also adversely affected by E-cigarette vapor exposure. E-cigarette-exposed human neutrophils exhibited a 48% reduction in production of reactive oxygen species (ROS; P < 0.001). Given the central role of ROS in neutrophil extracellular trap (NET) production, NET production was quantified, and E-cigarette vapor exposure was found to reduce NETosis by 3.5-fold (P < 0.01); formulations with and without nicotine containing propylene glycol exhibiting significant suppressive effects. However, noncanonical NETosis was unaffected. In addition, exposure to E-cigarette vapor lowered the rate of phagocytosis of bacterial bioparticles by 47% (P < 0.05). In our physiological mouse model of chronic E-cigarette exposure and sepsis, E-cigarette vapor inhalation led to reduced neutrophil migration in infected spaces and a higher burden of Pseudomonas. These findings provide evidence that E-cigarette use adversely impacts the innate immune system and may place E-cigarette users at higher risk for dysregulated inflammatory responses and invasive bacterial infections.

Effects of Chronic Inhalation of Electronic Cigarette Vapor Containing Nicotine on Neurotransmitters in the Frontal Cortex and Striatum of C57BL/6 Mice

Electronic (E)-cigarettes are the latest form of nicotine delivery device and are highly popular in the general population. It is currently unknown whether vaping E-cigarettes (E-CIGs) leads to nicotine addiction. Alterations in the levels of the neurotransmitters in the mesocorticolimbic areas have been reported to mediate the initiation and development of nicotine addiction. Therefore, to determine whether E-CIGs activate the same addiction pathways as conventional cigarettes, we investigated for the effects of daily inhalation of nicotine (24 mg/ml)-containing E-CIG vapor for 6 months on the concentrations of these neurotransmitters in the frontal cortex (FC) and striatum (STR) of male C57BL/6 mice as compared to control group that was exposed to air only. We reported here that 6-month E-CIG vapor containing nicotine inhalation decreased dopamine concentration only in the STR. There were no changes in serotonin concentrations in the FC or STR. Chronic E-CIG exposure also increased glutamate concentration in the STR alone, while glutamine concentrations were increased in both the FC and STR. We found that E-CIG exposure also decreased GABA concentration only in the FC. These data suggest that chronic E-CIG use alters homeostasis of several neurotransmitters in the mesocorticolimbic areas, which may result in the development of nicotine dependence in E-CIG users.

The HtrA1 promoter polymorphism, smoking, and age-related macular degeneration in multiple case-control samples

OBJECTIVE

To assess the association and combined effect on the risk of age-related macular degeneration (AMD) by the HtrA1 and complement factor H (CFH) polymorphisms, smoking, and serum cholesterol.

DESIGN

Clinic-based and population-based case control study.

PARTICIPANTS

A total of 805 AMD cases and 921 controls from The Eye Clinic of National Eye Institute, Age-Related Eye Diseases Study, Blue Mountain Eye Study Cohort, and Minnesota Lions Eye Bank.

METHODS

DNA samples were genotyped for polymorphisms of rs11200638 in HtrA1 promoter and rs380390 in CFH. HtrA1 protein in ocular tissue was measured. Interactions of the HtrA1 risk allele with the CFH risk variant, smoking status, and cholesterol were assessed.

MAIN OUTCOME MEASURES

AMD was evaluated by retinal specialists, and AMD subtypes (geographic atrophy and neovascularization) were determined.

RESULTS

Strong associations of the HtrA1 risk allele (A) with AMD were present in all sample sets. A similar magnitude of association was observed for central geographic atrophy and neovascular AMD. The combination of the HtrA1 and CFH risk alleles increased AMD susceptibility, as did the combination of the HtrA1 risk allele with smoking. No combined effect of HtrA1 risk allele and cholesterol level was found. Enhanced expression of HtrA1 protein was detected in retina with AMD.

CONCLUSIONS

Findings from multiple samples support an AMD genetic variant harbored within HtrA1. The risk of advanced AMD increased when the presence of risk alleles from HtrA1 was combined with either CFH risk alleles or history of smoking.

Ccl2/Cx3cr1-deficient mice: an animal model for age-related macular degeneration

BACKGROUND/AIMS

Senescent Ccl2-/- mice develop cardinal features of human age-related macular degeneration (AMD). Loss-of-function single-nucleotide polymorphisms within CX3CR1 are associated with AMD.

METHODS

We generated Ccl2-/-/Cx3cr1-/- [double-knockout (DKO)] mice and evaluated the eyes using fundoscopy routine histology, immunochemistry, biochemistry and proteomics.

RESULTS

At 6 weeks old, all DKO mice developed AMD-like retinal lesions such as abnormal retinal pigment epithelium cells, drusen, photoreceptor atrophy and choroidal neovascularization, which progressed with age and reversed with high omega-3 long-chain polyunsaturated fatty acid diet. N-retinylidene-N-retinylethanolamine (A2E), a major lipofuscin fluorophore, illustrated by an emission peak at approximately 600 nm, was significantly higher in DKO retinal pigment epithelium. Decreased ERp29 was found in the retina of DKO mice.

CONCLUSION

A broad spectrum of AMD pathologies with early onset and high penetrance in these mice implicate certain chemokines, A2E and endoplasmic reticulum proteins in AMD pathogenesis.

Immunological protein expression profile in Ccl2/Cx3cr1 deficient mice with lesions similar to age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness in the United States. Ccl2 knock-out (KO) mice sporadically develop the cardinal features of AMD in their senescent stage. Humans bearing a loss of function variant or single nucleotide polymorphism (SNP) in CX3CR1 are at increased risk of developing AMD. We recently developed Ccl2(-/-)/Cx3cr1(-/-) mice, which consistently develop retinal degeneration with many AMD features. Since there is strong evidence for an immunological role in AMD pathogenesis, we examined ocular immune protein expression levels in Ccl2(-/-)/Cx3cr1(-/-), Ccl2(-/-), Cx3cr1(-/-), and age-matched wild-type (WT) mice. Immunohistochemistry revealed increased complement C3d in Bruch's membrane, retinal pigment epithelium (RPE), choroidal capillaries, and particularly drusen of the Ccl2(-/-)/Cx3cr1(-/-) mice relative to the WT controls. No change was detected in single KO mice. Real-time RT-PCR revealed a 2.5-fold increase in C3 expression in the Ccl2(-/-)/Cx3cr1(-/-). While the retinas of four month old WT and Ccl2(-/-) showed minimal immunoreactivity for markers of macrophages and microglia, infiltrates of these mononuclear phagocytic cells were detected in the Ccl2(-/-)/Cx3cr1(-/-)retinal lesions and a few foci in the Cx3cr1(-/-) retina. The Ccl2(-/-)/Cx3cr1(-/-) had reduced toll-like receptor 4 (TLR4) expression in the RPE. Following LPS injection, the Ccl2(-/-)/Cx3cr1(-/-) had significantly reduced endotoxin-induced uveitis scores and showed a diminished increase in Tlr4 mRNA expression. No changes in TLR4 expression were detected in either single KO. Autoantibodies against the retina and photoreceptors were also detected in the Ccl2(-/-)/Cx3cr1(-/-) serum. Real-time RT-PCR revealed significant increases in Ccl5 transcript in the Ccl2(-/-)/Cx3cr1(-/-) relative to the WT. These results suggest that innate immunity and possibly adaptive immunity play an important role in Ccl2(-/-)/Cx3cr1(-/-) retinal degeneration. Moreover, since human AMD patients show similar immunopathological profiles, these results support the Ccl2(-/-)/Cx3cr1(-/-) as a suitable model for human AMD.

Murine ccl2/cx3cr1 deficiency results in retinal lesions mimicking human age-related macular degeneration

PURPOSE

Senescent Ccl2(-/-) mice are reported to develop cardinal features of human age-related macular degeneration (AMD). Loss-of-function single-nucleotide polymorphisms within CX3CR1 are also found to be associated with AMD. The authors generated Ccl2(-/-)/Cx3cr1(-/-) mice to establish a more characteristic and reproducible AMD model.

METHODS

Single Ccl2- and Cx3cr1-deficient mice were crossbred to obtain Ccl2(-/-)/Cx3cr1(-/-) mice. Funduscopy, histopathology, retinal A2E quantification, proteomics, RT-PCR gene expression assay, immunochemistry, and Western blotting were used to examine the retina and to evaluate gene expression within the retinal tissue.

RESULTS

By 6 weeks of age, all Ccl2(-/-)/Cx3cr1(-/-) mice developed AMD-like retinal lesions, including drusen, retinal pigment epithelium alteration, and photoreceptor degeneration. Furthermore, choroidal neovascularization occurred in 15% of the mice. These degenerative lesions progressed with age. A2E, a major lipofuscin fluorophore that accumulated during AMD progression, was significantly higher in the Ccl2(-/-)/Cx3cr1(-/-) retina than in the wild-type retina. Complement cofactor was higher in the Ccl2(-/-)/Cx3cr1(-/-) RPE. Proteomics data indicated that four proteins were differentially expressed in Ccl2(-/-)/Cx3cr1(-/-) retina compared with control. One of these proteins, ERp29, an endoplasmic reticulum protein, functions as an escort chaperone and in protein folding.

CONCLUSIONS

The authors concluded that Ccl2(-/-)/Cx3cr1(-/-) mice develop a broad spectrum of AMD abnormalities with early onset and high penetrance. These observations implicate certain chemokines and endoplasmic reticulum proteins in AMD pathogenesis. Similar to the mechanism of neurodegeneration caused by dysfunction of endoplasmic reticulum proteins, decreased chaperoning may cause misfolded protein accumulation, leading to drusen formation and retinal degeneration.

The LOC387715 polymorphism and age-related macular degeneration: replication in three case-control samples

PURPOSE

Age-related macular degeneration (AMD) is a multifactorial blinding disease in the elderly. LOC387715 harbors a single-nucleotide polymorphism that has an association with AMD. This study was conducted to confirm the association between LOC387715 and AMD and to refine estimates of the impact of this gene variation in using samples from three studies: an Australian population-based study and two U.S. clinic-based case-control studies.

METHODS

Cases and controls were collected from a National Eye Institute (NEI) clinical protocol (n = 240), the Age-Related Eye Disease Study (AREDS; n = 488), and the Blue Mountains Eye Study (BMES; n = 851). After DNA extraction, subjects were genotyped for the LOC387715 Ala69Ser polymorphism (rs10490924).

RESULTS

The combined NEI and AREDS samples yielded odds ratios (ORs) of 2.61 (95% CI 1.89-3.61, P = 1.42 x 10(-9)) and 8.59 (95% CI 4.49-16.5, P = 3.56 x 10(-13)) for the heterozygous and homozygous risk alleles, respectively. The corresponding odds ratios in the BMES sample were 1.69 (95% CI: 1.25-2.28, P = 0.0007) and 2.20 (95% CI: 1.05-4.62, P = 0.038) for the heterozygous and homozygous groups. Neither set of samples showed statistically significant interaction with smoking, although there appeared to be a trend of interaction between smoking and LOC387715 for risk of advanced AMD.

CONCLUSIONS

Although these data from three case-control samples support an AMD genetic risk marker harbored within LOC387715, the nested case-control data from the population-based BMES samples showed lower estimates than from the clinic-based samples. This may be because the BMES samples consisted of largely early AMD cases while the clinic-based AMD samples consisted exclusively of advanced cases.

Molecular pathology and CXCR4 expression in surgically excised retinal hemangioblastomas associated with von Hippel-Lindau disease

PURPOSE

The surgical excision of retinal vascular lesions including hemangioblastomas is rarely practiced. This study investigates the pathological characteristics of 4 patients (3 with von Hippel-Lindau [VHL] disease and 1 with a vasoproliferative retinal tumor) who underwent ocular tumor resection. von Hippel-Lindau is an autosomal dominant disease caused by a defect of the VHL tumor suppressor gene. The VHL protein is required for oxygen-dependent degradation of hypoxia-inducible factor 1alpha. This factor regulates vascular endothelial growth factor (VEGF) and the chemokine receptor CXCR4. Retinal hemangioblastoma is the most common tumor observed in VHL disease. We investigated the expression of CXCR4; its ligand, CXCL12/SDF-1alpha; VEGF; and the VHL gene in VHL disease-associated retinal hemangioblastomas.

DESIGN

Interventional case series with immunohistological and molecular pathological analyses.

PARTICIPANTS

Immunohistochemistry and molecular pathology of the surgically excised retinal lesions were performed.

INTERVENTION

Large retinal hemangioblastomas (1-3 disc diameters) and vasoproliferative tumors were resected surgically after laser photocoagulation in 4 patients. The excised tissues were snap frozen and evaluated by histology. Molecular pathology was performed for the VHL gene, and immunohistochemistry and molecular detection (reverse transcription polymerase chain reaction) were carried out for VEGF, CXCR4, and CXCL12.

MAIN OUTCOME MEASURES

Evaluation of clinical presentations and molecular pathology of the excised retinal lesions.

RESULTS

Large retinal hemangioblastomas were resected successfully from the 3 VHL cases. Postoperatively, all patients were stable. Molecular analyses disclosed the loss of heterozygosity at the VHL allele locus in the VHL retinal hemangioblastomas but not in the vasoproliferative tumor. High levels of transcript and protein were found for VEGF and CXCR4, whereas low levels of CXCL12 mRNA were expressed in the retinal hemangioblastomas associated with VHL disease. In contrast, very low levels of VEGF and CXCR4 mRNA were detected in the vasoproliferative tumor. Furthermore, increased expression of VEGF and CXCR4 was detected in more active hemangioblastomas.

CONCLUSIONS

Surgical resection of large retinal hemangioblastomas may be useful for therapy in selected VHL patients. Activated VHL lesions produce more VEGF. This is the first demonstration of CXCR4 expression in VHL disease-associated retinal hemangioblastomas. We suggest targeting CXCR4 as an additional therapeutic strategy for VHL disease-associated retinal hemangioblastomas.

An apolipoprotein E variant may protect against age-related macular degeneration through cytokine regulation

Age-related macular degeneration (AMD) is the leading cause of visual impairment and blindness among the elderly in Western countries. Genetic factors, age, cigarette smoking, nutrition, and exposure to light have been identified as AMD risk factors. In this study, we investigated the association between ApoE C112R/R158C single nucleotide polymorphisms (which determine the E2, E3, and E4 isoforms) and age-related macular degeneration (AMD), and the mechanism underlying the association. Genomic DNA was extracted from 133 clinically screened controls, 94 volunteers with a younger mean age, 120 patients with advanced AMD, and 40 archived ocular AMD slides for single nucleotide polymorphism typing. The effects of recombinant ApoE isoforms on CCL2 (a chemokine), CX3CR1 (a chemokine receptor), and VEGF (a cytokine) expression in cultured human retinal pigment epithelium (RPE) cells were tested and serum cholesterol profiles of the clinically screened subjects were analyzed. ApoE112R (E4) distribution differed significantly between AMD patients and controls. ApoE112R allele frequency was 10.9% in the AMD group when compared with 16.5% in the younger controls and 18.8% in the clinically screened controls. The pathologically diagnosed archived AMD cases had the lowest allele frequency of 5%. No significant differences in ApoE158C (E2) distribution were observed among the groups. A meta-analysis of 8 cohorts including 4,289 subjects showed a strong association between AMD and 112R, but not 158C. In vitro studies found that recombinant ApoE suppresses CCL2 and VEGF expression in RPE cells. However, the E4 isoform showed more suppression than E3 in both cases. These results further confirm the association between ApoE112R and a decreased risk of AMD development. The underlying mechanisms may involve differential regulation of both CCL2 and VEGF by the ApoE isoforms.

Synergic effect of polymorphisms in ERCC6 5' flanking region and complement factor H on age-related macular degeneration predisposition

This study investigates age-related macular degeneration (AMD) genetic risk factors through identification of a functional single-nucleotide polymorphism (SNP) and its disease association. We chose ERCC6 because of its roles in the aging process, DNA repair, and ocular degeneration from the gene disruption. Bioinformatics indicated a putative binding-element alteration on the sequence containing C-6530>G SNP in the 5' flanking region of ERCC6 from Sp1 on the C allele to SP1, GATA-1, and OCT-1 on the G allele. Electrophoretic mobility shift assays displayed distinctive C and G allele-binding patterns to nuclear proteins. Luciferase expression was higher in the vector construct containing the G allele than that containing the C allele. A cohort of 460 advanced AMD cases and 269 age-matched controls was examined along with pathologically diagnosed 57 AMD and 18 age-matched non-AMD archived cases. ERCC6 C-6530>G was associated with AMD susceptibility, both independently and through interaction with an SNP (rs380390) in the complement factor H (CFH) intron reported to be highly associated with AMD. A disease odds ratio of 23 was conferred by homozygozity for risk alleles at both ERCC6 and CFH compared with homozygozity for nonrisk alleles. Enhanced ERCC6 expression was observed in lymphocytes from healthy donors bearing ERCC6 C-6530>G alleles. Intense immunostaining of ERCC6 was also found in AMD eyes from ERCC6 C-6530>G carriers. The strong AMD predisposition conferred by the ERCC6 and CFH SNPs may result from biological epistasis, because ERCC6 functions in universal transcription as a component of RNA pol I transcription complex.

Differential diagnosis of anterior chamber cysts with ultrasound biomicroscopy: ciliary body medulloepithelioma

PURPOSE

To describe a case with motile cyst in the anterior chamber in the right eye of a 7-year-old boy.

METHODS

The right eye's visual acuity was 20/50. Intraocular pressure was 59 mmHg. Slit-lamp examination showed prominent rubeosis iridis and a grey-white mass floating freely in the anterior chamber. Ultrasound biomicroscopy revealed a cystic mass in the anterior chamber. A diagnostic cyclectomy with removal of the anterior chamber cyst was performed. Histopathology of the anterior chamber lesion showed an intact cyst composed of medullary epithelial cells. Medulloepithelioma with malignant criteria was diagnosed and the eye was enucleated.

RESULTS

Pathology demonstrated an medulloepithelioma with a few mitotic figures and nuclear pleomorphisms within the ciliary body. The patient was followed for 8 months without any metastasis in the orbit or elsewhere.

CONCLUSION

Intraocular medulloepithelioma is a rare embryonic benign or malignant neoplasm typically diagnosed in the first decade of life as a ciliary body mass. A dislodged, free-floating anterior chamber cyst associated with neovascular glaucoma is typical of medulloepithelioma in children. This unique presentation should be differentiated from congenital iris epithelial, post-traumatic, epithelial, parasitic and neoplastic cysts. Ultrasound biomicroscopy is useful for analysing the structure of the anterior segment mass. Ciliary body medulloepithelioma is characterized by echogenic mass heterogeneity and an irregular surface containing multiple cystic cavities. Lack of glial differentiation may predict a better clinical outcome in primary neuroectodermal brain tumours.

Exacerbation of retinal degeneration and choroidal neovascularization induced by subretinal injection of Matrigel in CCL2/MCP-1-deficient mice

This study presents a mouse model for human age-related macular degeneration (AMD) as characterized by subretinal deposit and choroidal neovascularization. Matrigel, a basement membrane extract, solidifies after implantation in tissue and can stimulate local angiogenesis. This study demonstrates the induction of neovascularization and focal retinal degeneration following subretinal Matrigel injection in mice. In senescent mice, the normal functioning of CC chemokine CCL2/MCP-1 and its receptor CCR2 confers protection against age-related retinal degeneration, a disease that shares many similar features with human AMD. Our data shows that CCL2-deficient mice develop more severe disease as compared to the wild-type controls. These findings suggest that Matrigel subretinal injection could be used to generate AMD-like pathological changes. The data support the previously proposed role of CCL2 in AMD pathogenesis.

Detection of CX3CR1 single nucleotide polymorphism and expression on archived eyes with age-related macular degeneration

There is a significant genetic component in age-related macular degeneration (AMD). CX3CR1, which encodes the fractalkine (chemokine, CX3CL1) receptor, has two single nucleotide polymorphisms (SNPs): V249I and T280M. These SNPs are correlated with other aged-related diseases such as atherosclerosis. We have reported an association of CX3CR1 SNP and AMD. In this study we examined CX3CR1 SNP frequencies and protein expression on archived sections of AMD and normal eyes. We microdissected non-retinal, peripheral retinal and macular cells from archived slides of eyes of AMD patients and normal subjects. CX3CR1 SNP typing was conducted by PCR and restriction fragment length polymorphism analysis. CX3CR1 transcripts from retinal cells were also measured using RT-PCR. CX3CR1 protein expression was evaluated using avidin-biotin complex immunohistochemistry. We successfully extracted DNA from 32/40 AMD cases and 2/2 normal eyes. Among the 32 AMD cases, 18 had neovascular AMD and 14 had non-neovascular AMD. The M280 allele was detected in 19/64 (32 cases x2) with a frequency of 29.7%, which was significantly higher as compared to the frequency in the normal population (11.2%). We detected CX3CR1 expression in the various retinal cells. CX3CR1 transcript and protein levels were diminished in the macular lesions. This study successfully analyzed CX3CR1 SNP and transcript expression in microdissected cells from archived paraffin fixed slides. Our data suggest that the M280 allele, a SNP resulting in aberrant CX3CR1 and CX3CL1 interaction, as well as lowered expression of macular CX3CR1, may contribute to the development of AMD.

Analysis of Hemicentin-1, hOgg1, and E-selectin single nucleotide polymorphisms in age-related macular degeneration

PURPOSE

Age-related macular degeneration (AMD) is a common disease in which both environmental and genetic factors have been implicated. Various single nucleotide polymorphisms (SNPs) have been correlated, through candidate gene association studies, with age-related diseases, including AMD. Recently we identified an association between AMD and two SNPs in CX3CR1, which encodes a chemokine receptor. This study investigates the Hemicentin-1 (an extracellular matrix protein) Q5345R, hOgg1 (DNA repair gene) S326C, and E-selectin (an adhesion molecule) S149R SNPs in association with AMD.

METHODS

Genomic DNA was extracted from peripheral blood of 89 patients with advanced AMD, 97 age-matched controls without clinical AMD, and 170 random unscreened healthy volunteers. DNA was subjected to polymerase chain reaction amplification coupled with the restriction fragment length polymorphism assay.

RESULTS

The distribution of the Hemicentin-1 Q5345R, hOgg1 S326C, and E-selectin S149R SNPs did not differ significantly (all P values > .05) between the AMD patients and controls. Hemincentin-1 5345R was not found in any subject. hOgg1 326C allele frequency was 21.35% (38 of 178) in the AMD group compared with 19.12% (65 of 340) in the random controls and 19.59% (38 of 194) in the age-matched controls. E-selectin 149R allele frequencies were 8.99% (16 of 178) in AMD cases, 9.41% (32 of 340) in random controls, and 10.82% (21 of 194) in age-matched controls.

CONCLUSIONS

We were not able to demonstrate an association between the Hemicentin-1, hOgg1, and E-selectin SNPs and AMD development in the currently available cases and controls. Further candidate genes, particularly those involved in extracellular matrix, oxidative stress, and immune system functions, are currently being screened in our laboratory.

Genetic factors of age-related macular degeneration

Age-related macular degeneration (AMD) is a leading cause of blindness in the United States and developed countries. Although the etiology and pathogenesis of AMD remain unknown, a complex interaction of genetic and environmental factors is thought to exist. The incidence and progression of all of the features of AMD are known to increase significantly with age. The tendency for familial aggregation and the findings of gene variation association studies implicate a significant genetic component in the development of AMD. This review summarizes in detail the AMD-related genes identified by studies on genetically engineered and spontaneously gene-mutated (naturally mutated) animals, AMD chromosomal loci identified by linkage studies, AMD-related genes identified through studies of monogenic degenerative retinal diseases, and AMD-related gene variation identified by association studies.