Epidemiologic study of microplastic pollution in bronchoalveolar lavage fluid and its association with lung cancer - ABSTRACT
An estimated 400 metric tons of plastic are produced each year worldwide and less than 10% is recycled.
Microplastics (MPs) defined as particles <5mm generated from weathering and wear of discarded plastic trash,
tires and textiles are now ubiquitous in the environment. MPs enter the body by ingestion, inhalation and contact
with skin and MPs have been identified in all human tissue types studied including blood, placenta and lung. The
impacts of internalized MPs on health are unknown. Given that MPs may be coated with toxic chemicals and
‘biofilms’ containing pathogens, and the physical presence of MPs may induce local inflammatory and immune
responses, there is urgent need to establish carcinogenic potential of MP exposures in body sites such as the
lung. In this R21 we propose to interrogate bronchoalveolar lavage (BAL) fluid for MPs in thoracic oncology
patients to gain insights on the potential relationship of MPs with lung cancer (LCa), the leading cancer diagnosis
and cause of cancer death in the US and most western countries. Prior studies have documented BAL as a
minimally invasive approach to isolate and characterize MPs in the airway of living persons. In the proposed
R21, a total of ~275 patients undergoing BAL at Moffitt Cancer Center, Tampa, FL for suspected new primary
LCa, staging of another primary neoplasm, or diagnosis of lung infection will be enrolled and a 10-mL sample of
recovered BAL fluid reserved for study of MPs. Patients with a history of surgeries or BAL of the affected lung
will be ineligible. Participants will complete a survey on demographics, smoking and occupational history, and
medical records will be reviewed to capture history of pulmonary diseases and procedures. MPs in BAL fluid will
be studied in a physics laboratory at the University of South Florida, Tampa, FL and characterized for abundance
and morphology using standard optical and Atomic Force Microscopy, and for chemical composition using
Raman spectroscopy, methods widely used in emerging studies of MPs in biologic and environmental samples.
Stringent processes will be in place to limit contamination from ambient MPs in the clinic and lab. In a series of
300 study participants, including ~25 from our recently initiated pilot study, patients with confirmed incident LCa
(~50% of the participants) will be compared to patients with other pathologies on total number of MPs in BAL
samples with adjustment for patient age, gender, race, smoking history and occupation in regression models.
Associations will be examined with LCa overall and, in exploratory analyses, with LCa subtype (i.e.,
adenocarcinoma versus other LCas). Other features of MPs including morphology, polymer subtype (e.g.,
polyethylele terephthalate (i.e., polyester); polypropylene; and semisynthetic polymer fibers (i.e., rayon)), and
surface coatings and contaminants will also be explored for associations with LCa risk. The proposed
investigation offers one of the first studies to examine MP impacts on human health with a focus on LCa. Data
generated will help fill an important knowledge gap and provide a foundation for future research on this now
ubiquitous pollutant worldwide.
