E-cigarette or vaping product use-associated lung injury: What is the role of cytologic assessment?

E-Cigarette or Vaping Product Use-Associated Lung Injury: A Comprehensive Review

E-cigarette or vaping product use-associated lung injury (EVALI) is a critical and potentially fatal form of lung injury that gained considerable public health concern in 2019. The use of e-cigarettes and vaping products is causally associated with EVALI, a condition characterized by a constellation of respiratory symptoms, such as coughing, shortness of breath, and chest pain. This comprehensive narrative literature review explores the complexities of EVALI, including its association with the structure and composition of e-cigarettes and its epidemiology, pathogenesis, clinical and radiological manifestations, management strategies, and public health implications. Moreover, it uncovers the long-term repercussions of EVALI and underscores the ongoing research endeavors designed to mitigate and comprehend the risks associated with using e-cigarettes.

Acute exposure to electronic cigarette components alters mRNA expression of pre-osteoblasts

The use of traditional nicotine delivery products such as tobacco has long been linked to detrimental health effects. However, little work to date has focused on the emerging market of aerosolized nicotine delivery known as electronic nicotine delivery systems (ENDS) or electronic cigarettes, and their potential for new effects on human health. Challenges studying these devices include heterogeneity in the formulation of the common components of most available ENDS, including nicotine and a carrier (commonly composed of propylene glycol and vegetable glycerin, or PG/VG). In the present study, we report on experiments interrogating the effects of major identified components in e-cigarettes. Specifically, the potential concomitant effects of nicotine and common carrier ingredients in commercial "vape" products are explored in vitro to inform the potential health effects on the craniofacial skeleton through novel vectors as compared to traditional tobacco products. MC3T3-E1 murine pre-osteoblast cells were cultured in vitro with clinically relevant liquid concentrations of nicotine, propylene glycol (PG), vegetable glycerin (VG), Nicotine+PG/VG, and the vape liquid of a commercial product (Juul). Cells were treated acutely for 24 h and RNA-Seq was utilized to determine segregating alteration in mRNA signaling. Influential gene targets identified with sparse partial least squares discriminant analysis (sPLS-DA) implemented in mixOmics were assessed using the PANTHER Classification system for molecular functions, biological processes, cellular components, and pathways of effect. Additional endpoint functional analyses were used to confirm cell cycle changes. The initial excitatory concentration (EC50) studied defined a target concentration of carrier PG/VG liquid that altered the cell cycle of the calvarial cells. Initial sPLS-DA analysis demonstrated the segregation of nicotine and non-nicotine exposures utilized in our in vitro modeling. Pathway analysis suggests a strong influence of nicotine exposures on cellular processes including metabolic processes and response to stimuli including autophagic flux. Further interrogation of the individual treatment conditions demonstrated segregation by treatment modality (Control, Nicotine, Carrier (PG+VG), Nicotine+PG/VG) along three dimensions best characterized by: latent variable 1 (PLSDA-1) showing strong segregation based on nicotine influence on cellular processes associated with cellular adhesion to collagen, osteoblast differentiation, and calcium binding and metabolism; latent variable 2 (PLSDA-2) showing strong segregation of influence based on PG+VG and Control influence on cell migration, survival, and cycle regulation; and latent variable 3 (PLSDA-3) showing strong segregation based on Nicotine and Control exposure influence on cell activity and growth and developmental processes. Further, gene co-expression network analysis implicates targets of the major pathway genes associated with bone growth and development, particularly craniofacial (FGF, Notch, TGFβ, WNT) and analysis of active subnetwork pathways found these additionally overrepresented in the Juul exposure relative to Nicotine+PG/VG. Finally, experimentation confirmed alterations in cell count, and increased evidence of cell stress (markers of autophagy), but no alteration in apoptosis. These data suggest concomitant treatment with Nicotine+PG/VG drives alterations in pre-osteoblast cell cycle signaling, specifically transcriptomic targets related to cell cycle and potentially cell stress. Although we suspected cell stress and well as cytotoxic effects of Nicotine+PG/VG, no great influence on apoptotic factors was observed. Further RNA-Seq analysis allowed for the direct interrogation of molecular targets of major pathways involved in bone and craniofacial development, each demonstrating segregation (altered signaling) due to e-cigarette-type exposure. These data have implications directed toward ENDS formulation as synergistic effects of Nicotine+PG/VG are evidenced here. Thus, future research will continue to interrogate how varied formulation of Nicotine+PG/VG affects overall cell functions in multiple vital systems.

In Utero Exposure to Maternal Electronic Nicotine Delivery System use Demonstrate Alterations to Craniofacial Development

OBJECTIVE

Develop a model for the study of Electronic Nicotine Device (ENDS) exposure on craniofacial development.

DESIGN

Experimental preclinical design followed as pregnant murine dams were randomized and exposed to filtered air exposure, carrier exposure consisting of 50% volume of propylene glycol and vegetable glycine (ENDS Carrier) respectively, or carrier exposure with 20 mg/ml of nicotine added to the liquid vaporizer (ENDS carrier with nicotine).

SETTING

Preclinical murine model exposure using the SciReq exposure system.

PARTICIPANTS

C57BL6 adult 8 week old female pregnant mice and exposed in utero litters.

INTERVENTIONS

Exposure to control filtered air, ENDS carrier or ENDS carrier with nicotine added throughout gestation at 1 puff/minute, 4 h/day, five days a week.

MAIN OUTCOME MEASURES

Cephalometric measures of post-natal day 15 pups born as exposed litters.

RESULTS

Data suggests alterations to several facial morphology parameters in the developing offspring, suggesting electronic nicotine device systems may alter facial growth if used during pregnancy.

CONCLUSIONS

Future research should concentrate on varied formulations and exposure regimens of ENDS to determine timing windows of exposures and ENDS formulations that may be harmful to craniofacial development.

The E-cigarette or Vaping Product Use-Associated Lung Injury Epidemic: Pathogenesis, Management, and Future Directions: An Official American Thoracic Society Workshop Report

E-cigarette or vaping product use-associated lung injury (EVALI) is a severe pulmonary illness associated with the use of e-cigarettes or vaping products that was officially identified and named in 2019. This American Thoracic Society workshop was convened in 2021 to identify and prioritize research and regulatory needs to adequately respond to the EVALI outbreak and to prevent similar instances of disease associated with e-cigarette or vaping product use. An interdisciplinary group of 26 experts in adult and pediatric clinical care, public health, regulatory oversight, and toxicology were convened for the workshop. Four major topics were examined: 1) the public health and regulatory response to EVALI; 2) EVALI clinical care; 3) mechanisms contributing to EVALI; and 4) needed actions to address the health effects of EVALI. Oral presentations and group discussion were the primary modes used to identify top priorities for addressing EVALI. Initiatives including a national EVALI case registry and biorepository, integrated electronic medical record coding system, U.S. Food and Drug Administration regulation and enforcement of nicotine e-cigarette standards, regulatory authority over nontobacco-derived e-cigarettes, training in evaluating exogenous exposures, prospective clinical studies, standardized clinical follow-up assessments, ability to more readily study effects of cannabinoid e-cigarettes, and research to identify biomarkers of exposure and disease were identified as critical needs. These initiatives will require substantial federal investment as well as changes to regulatory policy. Overall, the workshop identified the need to address the root causes of EVALI to prevent future outbreaks. An integrated approach from multiple perspectives is required, including public health; clinical, basic, and translational research; regulators; and users of e-cigarettes. Improving the public health response to reduce the risk of another substantial disease-inducing event depends on coordinated actions to better understand the inhalational toxicity of these products, informing the public of the risks, and developing and enforcing regulatory standards for all e-cigarettes.

Oil Red O Staining of Pulmonary Macrophages in Bronchoalveolar Lavage Specimens Is Not Specific for Vaping-Associated Lung Injury

Objectives

Oil Red O (ORO) positivity in bronchoalveolar lavage (BAL) fluid macrophages in the setting of e-cigarette, or vaping, product use–associated acute lung injury (EVALI) has been frequently requested by clinicians based on rare reports and subsequent US Centers for Disease Control and Prevention guidelines. The aim of this study was to determine the specificity of ORO staining in BAL specimens with disease states other than EVALI.

Methods

Consecutive BAL specimens (October-December 2019) were stained with ORO. The lipid-laden macrophage index (LLMI) was calculated for each case.

Results

We studied BAL samples from 50 patients. Indications for BAL were surveillance bronchoscopy for lung transplantation (27/50), suspected infection (12/50), sarcoidosis/suspected sarcoidosis (3/50), nodules or ground-glass opacities (3/50), hemoptysis (2/50), asthma or eosinophilic pneumonia (2/50), and idiopathic pulmonary fibrosis (1/50). ORO staining was seen in BAL fluid macrophages in 45 of 50 cases (focal in 18, moderate in 23, diffuse in 4); LLMI ranged from 0 to 218. Using a threshold of LLMI of 85 or higher as positive, ORO was positive in 7 of 50 (14%) cases (range, 85-218).

Conclusions

ORO staining in BAL fluid macrophages is not specific for EVALI. Even when an LLMI of 85 or higher is used as a threshold for positivity, ORO positivity occurs in a significant subset of non–vaping-related cases.

Significance of Oil-Red-O positive macrophages in bronchoalveolar lavage in diagnosing E-cigarettes or vaping product use-associated lung injury: A case series

BACKGROUND

Lipid-laden macrophages detected by Oil-Red-O (ORO) stain in fresh bronchoalveolar lavage (BAL) specimens have been proposed as a potential diagnostic marker for E-cigarettes or vaping product use-associated lung injury (EVALI). However, studies are few, and the sensitivity and specificity of the test have not been thoroughly investigated.

METHODS

We performed ORO stain on fresh BAL specimens from six confirmed EVALI and 36 non-EVALI patients. After semi-quantitative analysis, the sensitivity and specificity of ORO-positive macrophages (OPM) for detection of EVALI were calculated.

RESULTS

No significant difference in cytomorphology or raw macrophage count was observed between EVALI and non-EVALI groups (49% vs 55% of all nucleated cells). However, with ORO stain, all EVALI specimens (6/6) showed a high percentage (≥50% of all macrophages) of OPM (mean 87%), and large (≥25% of host macrophage nuclear size) lipid droplets (mean 42%), while the majority of non-EVALI specimens showed a low percentage of OPM (32/36, mean 10%), and small lipid droplets (34/36, mean 6%). The differences between the two groups in both high OPM and large lipid droplet rates are statistically significant (P < .0001 for both comparisons). The combined sensitivity and specificity of high OPM and large lipid droplets for diagnosing EVALI were 100% and 94%, respectively.

CONCLUSION

In BAL specimens obtained from patients with clinically suspected EVALI, a high percentage of OPM with large lipid droplets showed high sensitivity and specificity for the diagnosis of EVALI and may serve as a potentially useful tool in the evaluation of vaping-related lung injury, improving diagnostic accuracy.

E-Cigarette or Vaping Product Use-Associated Lung Injury: A Review for Pathologists

CONTEXT.—

Vaping is the inhalation of heated aerosol from a small battery-powered device as a method to deliver nicotine or other substances. A recent outbreak of severe respiratory illness primarily in the United States has put a spotlight on vaping and its potential risks.

OBJECTIVE.—

To familiarize pathologists with vaping, the cytologic and histopathologic features of vaping-associated acute lung injury, and the role of pathology in this diagnosis.

DATA SOURCES.—

A targeted literature review was performed.

CONCLUSIONS.—

Most cases of vaping-associated lung injury have been linked to vaping products containing tetrahydrocannabinol or other cannabinoids. Lung biopsies show a spectrum of nonspecific acute lung injury patterns (organizing pneumonia, diffuse alveolar damage, acute fibrinous, and organizing pneumonia, or combinations of the above), accompanied by prominent, foamy macrophage accumulation. Injury is usually accentuated around small airways. Lipid-laden macrophages can be identified in bronchioloalveolar lavage fluid in most patients and these can be highlighted using lipid stains, such as oil red O, but the clinical utility of this finding remains unclear, as lipid-laden macrophages can be seen in a wide variety of processes and should not be relied upon to make the diagnosis. Classic histologic features of exogenous lipoid pneumonia have not been identified in tissue samples. Lightly pigmented macrophages, similar to those seen with traditional cigarette smoking, are present in some cases but are usually a minor feature. To date, no specific pathologic features for vaping-related injury have been identified, and it remains a diagnosis of exclusion that requires clinicopathologic correlation.

Vaping-related lung injury

The use of electronic nicotine delivery systems has increased in popularity dramatically over the past decade. Although lung diseases caused by vaping have been reported since the modern invention of the electronic cigarette, in the summer of 2019, patients began to present to health care centers at epidemic levels with an acute respiratory illness relating to vaping, which the Center for Disease Control termed E-cigarette or vaping product use-associated lung injury (EVALI). This review discusses electronic nicotine delivery systems as well as the etiology, clinical presentation, imaging findings, pathologic features, treatment, and long-term consequences of EVALI. We conclude with the practical impact EVALI has had on the practice of pathology.

Guidance on the Clinical Management of Electronic Cigarette or Vaping-Associated Lung Injury

In the summer of 2019, there was a rise in clusters of adolescents and young adults in the United States reporting to emergency departments with acute respiratory distress related to use of e-cigarette (electronic cigarette) or vaping. The number of patients with e-cigarette or vaping-associated lung injury continued to rise through the summer before peaking in September 2019. Through the efforts of state and federal public health agencies, officials were able to define the condition, identify the relationship of the respiratory injury to tetrahydrocannabinol-containing products, and stem the rise in new cases. In this report, we present a comprehensive review of the clinical characteristics and features of patients with e-cigarette or vaping-associated lung injury and guidelines for patient care and management to inform and navigate clinicians who may encounter these patients in their clinical practice.

The Texas Society of Pathologists: molded by the legacy of pathology and focused on excellence in medicine for 100 years and beyond

In 1921, 16 Texas pathologists gathered in Dallas, Texas, to found the Texas Society of Pathologists (TSP). The TSP is now the oldest state pathology society in the USA with continuity traced back to its founding 100 years ago. This article aims to both commemorate the TSP centennial and to provide context for the remarkable success of the society. The article takes a look back and a look forward from 1921. The look back focuses on the development of the field of pathology and the maturation of medicine and pathology in the USA and Texas. The look forward encompasses developments in science, technology, American health care policy, and medicine that have impacted Texas pathologists and influenced proactive initiatives of the TSP. The review of the life and times of the TSP highlights the importance of leaders and leadership in shaping outcomes. Complexities and uncertainties of the contemporary health care scene point to the need for continued strong leadership. The successful past century and hopeful future of the TSP are inextricably linked to the guiding principle of the TSP, which is a focus on continual striving for excellence in medicine.