Measurement of Lung Phosphatidylcholines in Exhaled Breath Particles by a Convenient Collection Procedure

Probing for factors influencing exhaled breath drug testing in sports- Pilot studies focusing on the tested individual's tobacco smoking habit and sex

RATIONALE

Exhaled breath (EB) was found to be a promising matrix in the field of sports drug testing due to the non-invasive and non-intrusive sampling procedure, but significant inter-individual variations regarding detected drug concentrations have been observed in previous studies. To investigate whether the detectability of doping agents in EB is affected by sex or tobacco smoking, two administration studies were conducted with male and female smokers and nonsmokers concerning the elimination of the beta blocker propranolol and the stimulant pseudoephedrine into EB.

METHODS

Following the administration of 40 mg propranolol or 30 mg pseudoephedrine, a total of 19 participants, including female and male nonsmokers as well as female and male smokers, collected EB and dried blood spot (DBS) samples over a period of 24 h. Respective analyte concentrations were determined using liquid chromatography and high-resolution tandem mass spectrometry, and semi-quantitative assays were characterized with regard to selectivity, limit of detection and identification, precision, linearity, and carryover.

RESULTS

Both propranolol and pseudoephedrine were identified in post-administration EB samples from female and male nonsmokers as well as female and male smokers, and the maximum detected drug levels ranged from 9 to 2847 pg/cartridge for propranolol and from 26 to 4805 pg/cartridge for pseudoephedrine. The corresponding DBS levels were in a range of 4-30 ng/mL for propranolol and 55-186 ng/mL for pseudoephedrine.

CONCLUSIONS

Neither the consumption of cigarettes nor the sex appears to represent a decisive criterion as to the detectability of propranolol or pseudoephedrine in EB, but inter-individual variations regarding the detected drug levels were observed among all studied population groups.

Sea Spray Aerosols Contain the Major Component of Human Lung Surfactant

Marine phytoplankton influence the composition of sea spray aerosols (SSAs) by releasing various compounds. The biogenic surfactant dipalmitoylphosphatidylcholine (DPPC) is known to accumulate in the sea surface microlayer, but its aerosolization has never been confirmed. We conducted a 1 year SSA sampling campaign at the Belgian coast and analyzed the SSA composition. We quantified DPPC at a median and maximum air concentration of 7.1 and 33 pg m^-3, respectively. This discovery may be of great importance for the field linking ocean processes to human health as DPPC is the major component of human lung surfactant and is used as excipient in medical aerosol therapy. The natural airborne exposure to DPPC seems too low to induce direct human health effects but may facilitate the effects of other marine bioactive compounds. By analyzing various environmental variables in relation to the DPPC air concentration, using a generalized linear model, we established that wave height is a key environmental predictor and that it has an inverse relationship. We also demonstrated that DPPC content in SSAs is positively correlated with enriched aerosolization of Mg²⁺ and Ca²⁺. In conclusion, our findings are not only important from a human health perspective but they also advance our understanding of the production and composition of SSAs.

The Role of Mass Spectrometry in the Cannabis Industry

The focus of this critical insight article is a brief overview of analytical challenges the cannabis industry faces and how analytical chemists have new opportunities to demonstrate the merits of employing mass spectrometry for the chemical analysis of cannabis and its products. The current range of cannabis products extends from recreational use to medicines, edibles, beverages, and beyond. The standards employed to assure product quality, integrity, and safety are lacking compared to those currently used by the pharmaceutical, food, and beverage industries. This manuscript overviews some of the important analytical issues that exist for the growth and harvest of the cannabis plant to the production of a wide variety of its products. Currently, the topics of interest for safety in cannabis testing where mass spectrometry can play an important role include what are currently referred to as potency, pesticides, terpenes, heavy metals, and mycotoxins from bacteria. Since each state in the USA as well as several countries has their own regulations, the analytical opportunities and challenges vary depending upon which jurisdiction a laboratory is supporting. This Critical Insight report will suggest where mass spectrometry can play an important role and provide valuable input on these topics. Graphical Abstract.

Non-volatile compounds in exhaled breath condensate: review of methodological aspects

In contrast to bronchial and nasal lavages, the analysis of exhaled breath condensate (EBC) is a promising, simple, non-invasive, repeatable, and diagnostic method for studying the composition of airway lining fluid with the potential to assess lung inflammation, exacerbations, and disease severity, and to monitor the effectiveness of treatment regimens. Recent investigations have revealed the potential applications of EBC analysis in systemic diseases. In this review, we highlight the analytical studies conducted on non-volatile compounds/biomarkers in EBC. In contrast to other related articles, this review is classified on the basis of analytical techniques and includes almost all the applied methods and their methodological limitations for quantification of non-volatile compounds in EBC samples, providing a guideline for further researches. The studies were identified by searching the SCOPUS database with the keywords "biomarkers," "non-volatile compounds," "determination method," and "EBC."

Evaluation of a new method for the collection and measurement of 8-isoprostane in exhaled breath for future application in nanoparticle exposure biomonitoring

BACKGROUND

In the field of nanoparticle exposure biomonitoring, oxidative stress biomarkers measured in exhaled breath condensate appear promising to detect early respiratory effects in workers handling nanomaterials. However, condensation is known for its poor efficiency in collecting non-volatiles in exhaled breath, leading to the low sensitivity of such measurements. Moreover, to be easily used in field studies on large groups of workers, the collection device must be disposable and convenient.

OBJECTIVES

In this study, we have tested a totally disposable commercial device that allows for the easy dry collection of exhaled air after filtration on a patented filter. The suitability and efficiency of the SensAbues (SB) device for collecting 8-isoprostane were evaluated and compared to the RTube (RT).

METHODS

Seven healthy volunteers performed two 15 min collections of exhaled breath, one with the SB and one with the RT. Blank devices were used to determine the background levels induced by each device. 8-isoprostane was measured in all samples using an EIA technique.

RESULTS

The levels of 8-isoprostane in the exhaled breath of volunteers after collection with the SB were significantly higher than those after collection with the RT. Moreover, the levels obtained in volunteers with the SB were significantly higher than background levels obtained in blank devices, which was not the case for the RT.

CONCLUSIONS

This is the first study to report the ability of the SB device to collect and measure 8-isoprostane in exhaled breath. The proposed method offers better sensitivity than a classical collection with the RT device and should be further explored before future application in biomonitoring studies.

Evaluation of a new simple collection device for sampling of microparticles in exhaled breath

The microparticle fraction of exhaled breath is of interest for developing clinical biomarkers. Exhaled particles may contain non-volatile components from all parts of the airway system, formed during normal breathing. This study aimed to evaluate a new, simple sampling device, based on impaction, for collecting microparticles from exhaled breath. Performance of the new device was compared with that of the existing SensAbues membrane filter device. The analytical work used liquid chromatography-tandem mass spectrometry methods. The new device collected three subsamples and these were separately analysed from eight individuals. No difference was observed between the centre position (0.91 ng/sample) and the side positions (1.01 ng/sample) using major phosphatidylcholine (PC) 16:0/16:0 as the analyte. Exhaled breath was collected from eight patients on methadone maintenance treatment. The intra-individual variability in measured methadone concentration between the three collectors was 8.7%. In another experiment using patients on methadone maintenance treatment, the sampling efficiency was compared with an established filter device. Compared to the existing device, the efficiency of the new device was 121% greater for methadone and 1450% greater for DPPC. The data from lipid analysis also indicated that a larger fraction of the collected material was from the distal parts. Finally, a study using an optical particle counter indicated that the device preferentially collects the larger particle fraction. In conclusion, this study demonstrates the usefulness of the new device for collecting non-volatile components from exhaled breath. The performance of the device was superior to the filter device in several aspects.

Non-invasive lung disease diagnostics from exhaled microdroplets of lung fluid: perspectives and technical challenges

The combination of ultra-sensitive assay techniques and recent improvements in the instrumentation used to collect microdroplets of lung fluid (MLF) from exhaled breath has enabled the development of non-invasive lung disease diagnostics that are based on MLF analysis. In one example of this approach, electrospun nylon filters were used to collect MLFs from patients with pulmonary tuberculosis. The filters were washed to obtain liquid probes, which were then tested for human immunoglobulin A (h-IgA) and fractions of h-IgA specific to ESAT-6 and Psts-1, two antigens secreted by Mycobacterium tuberculosis. Probes collected for 10 min contained 100-1500 fg of h-IgA and, in patients with pulmonary tuberculosis, a portion of these h-IgA molecules showed specificity to the secreted antigens. Separate MLFs and their dry residues were successfully collected using an electrostatic collector and impactor developed especially for this purpose. Visualization of MLF dry residues by atomic force microscopy made it possible to estimate the lipid content in each MLF and revealed mucin molecules in some MLFs. This exciting new approach will likely make it possible to detect biomarkers in individual MLFs. MLFs emerging from an infection site ('hot' microdroplets) are expected to be enriched with infection biomarkers. This paper discusses possible experimental approaches to detecting biomarkers in single MLFs, as well as certain technological problems that need to be resolved in order to develop new non-invasive diagnostics based on analysing biomarkers in separate MLFs.

Identification and quantitation of phosphatidylethanols in oral fluid by liquid chromatography-tandem mass spectrometry

BACKGROUND

Phosphatidylethanols (PEth) are formed from phosphatidylcholines and ethanol and are used as a specific and sensitive alcohol biomarker. An analytical method for analysis of PEth in oral fluid based on high-performance liquid chromatography coupled to a quadrupole tandem mass spectrometer (LC-MS/MS) was developed and validated and applied on samples collected from patients undergoing alcohol detoxification.

METHODS

A 200-μL aliquot of oral fluid, collected using the QuantisalTM device, was extracted with chloroform/methanol containing internal standard and subjected to LC-MS/MS analysis of three selected PEth forms (16:0/16:0, 16:0/18:1, and 16:0/18:2). Chromatographic separation was achieved on a UPLC BEH phenyl column, using a mobile phase consisting of acetonitrile and water containing 10 mmol/L ammonium hydrogen carbonate with 0.1% ammonia. The MS instrument was operated in negative electrospray ionization and selected reaction monitoring mode.

RESULTS

The detection limit for PEth 16:0/16:0, 16:0/18:1, and 16:0/18:2 was ~0.1 ng/mL, and the extraction recoveries at 2.0 ng/mL were in the range of 99%-114%. Method linearity over a concentration range up to 200 ng/mL was ≥0.99. No significant deviation in results was observed in an analyte stability study of two different concentrations at two different temperatures over 3 months. In 35 oral fluid samples collected from patients undergoing alcohol detoxification, the highest concentration was observed for PEth 16:0/18:1 (Detected range, 0.51-55.3 ng/mL; mean, 8.5; median, 3.1). In addition, all three PEth forms were variably identified in a majority (63%) of the oral fluid samples. The PEth 16:0/18:1 values in oral fluid showed a weak positive correlation with the corresponding values in whole blood samples (r=0.50, p=0.026, n=20).

CONCLUSIONS

The LC-MS/MS method could reliably detect and quantify PEth in oral fluid samples collected after alcohol exposure. The method was characterized by validation data with satisfactory recovery, sensitivity, accuracy, and imprecision, and applied for analysis of clinical samples. The results suggest that measurement of PEth in oral fluid can be used as a biomarker for alcohol consumption, and as such a non-invasive complement to analysis in blood. However, further studies are required to evaluate the test characteristics (e.g. sensitivity and half-life) in comparison with PEth in blood.