Volatile organic compounds of exhaled breath in lung

Volatile organic compounds of exhaled breath in lung cancer and inflammatory diseases Prof. Immanuels Taivans, Dr. biol. Gunta Strazda 1 2 3, Dr. biol. Normunds Jurka 2 Dr. med. Uldis Kopeika 4, , Dr. Ainis Pirtnieks 4 Līga Balode 1, Dr. med. Māris Bukovskis 1 23, Ms Agnese Kisļina, Dr. Jevgenija Aprinceva 1, Dr Liene Logina 1. 1 Faculty of Medicine, University of Latvia, 2 Institute of Experimental and Clinical Medicine, University of Latvia, 3 Department of Pulmonology and Allergology, Pauls Stradins Clinical University Hospital, 4 Department of Thoracic Surgery, Pauls Stradins Clinical University Hospital

• Previous studies of exhaled air using artificial nose have shown that this method allows to distiguish among different lung diseases. • Artificial nose senses the mixture of different chemical substances present in breath. • Which particular are these substances and what is their origin ? Are they produced by tumor cells, or they have another origin? Are there specific substances characteristic for lung inflammatory diseases?

• To find these answers we used highly sensitive detection method – gas chromatography combined with mass spectroscopy to study the presence of volatile organic compounds (VOCs) in exhaled air of 31 lung cancer patient, 19 persons with chronic obstructive lung disease (COPD), 11 pneumonia patients and 10 healthy persons.

• As indoor air contains volatile organic compounds in concentrations that may exceed the amounts present in exhaled air, special care was taken to clean the air that inhaled the investigated persons before taking the breath sample for analysis.

Before taking a breath sample patient for 3 minutes beathed pure, filtered air from a bag

Collected exhaled air was slowly sucked through the adsorbtion tube. It took approximately one hour.

Complex consisting of desorbtion unit, gas chromatograph and mass spectrometer

Chromatogram showing multiple peaks representing particular chemical substances

List of VOCs that underwent quantitative analysis We chose for quantitative analysis 19 VOCs mentioned in different previous studies as characteristic for lung cancer or lung inflammatory diseases: methanol, isopropanole, acetone, isoprene, benzene, p-xylene, o-xylene, phenole, styrene, toluene, pyridine, dichlormetane, pentane, hexane, heptane, decane, dodecane, tridecane

Results • In lung cancer patients majority of VOCs – candidates for cancer diagnosis had lower exhaled air concentrations compared to individuals with lung inflammatory diseases or even healthy persons. • It can be explained by more intensive metabolism of these compounds in cancerous state.

4 VOCs which content in exhaled air was significantly different in study groups

Conclusions • With rare exceptions VOCs in the exhaled air are not products of cancer cells; in majority of cases these are environmental pollutants metabolized by body in different ways which are changed by disease state. • Tumorous state or inflammation in different ways changes metabolism of VOCs of both endogenous and exogenous origin. • Differences in metabolism of VOCs allows to distinguish between cancer and lung inflammatory diseases when analysing the exhaled air.