Daniela Pelclova1, Vladimir Zdimal2, Petr Kacer3, Stepanka Vlckova1, Zdenka Fenclova1, Tomas Navratil4, Martin Komarc5,6, Jaroslav Schwarz2, Nadezda Zikova2, Otakar Makes2, Sergey Zakharov1. 1. Charles University and General University Hospital in Prague, 1st Faculty of Medicine, Department of Occupational Medicine, Prague, Czech Republic. 2. Institute of Chemical Process Fundamentals of the CAS CR, v.v.i., Prague, Czech Republic. 3. Institute of Chemical Technology Prague, Czech Republic. 4. J. Heyrovský Institute of Physical Chemistry of the CAS CR, v.v.i., Prague, Czech Republic. 5. Charles University, Faculty of Physical Education and Sport, Department of Kinanthropology and Humanities, Prague, Czech Republic. 6. Charles University, 1st Faculty of Medicine, Institute of Biophysics and Informatics, Prague, Czech Republic.
Abstract
OBJECTIVES: Experimental studies using nanoscale TiO2 have documented lung injury, inflammation, oxidative stress, and genotoxicity. Human health data are extremely scarce. METHODS: In exhaled breath condensate (EBC) and urine of 22 office employees occupationally exposed to TiO2 during their visit in the production workshops for average 14±9 min/day a panel of biomarkers of nucleic acids and proteins oxidation was studied, specifically 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), 5-hydroxymethyl uracil (5-OHMeU), o-tyrosine (o-Tyr), 3-chlorotyrosine (3-ClTyr), and 3-nitrotyrosine (3-NOTyr). Examination was performed also in 14 comparable controls. RESULTS: The median respirable TiO2 mass concentration in the workshops was 0.40 mg/m3, median number concentration was 2.32×104 particles/cm3 with 80% of the particles being <100 nm in diameter. All 6 markers of oxidation were elevated in EBC in factory office employees relative to controls (p<0.01). Significant association was found between their job in TiO2 production plant and 5 markers of oxidation (except 3-NOTyr) in the EBC in multivariate analysis. No elevation of markers was detected in the urine. CONCLUSION: This pilot study suggests that even short nanoTiO2 exposure may lead to pulmonary oxidative stress; however this effect may be short-term and reversible. The clinical significance of these findings is unclear and more studies are needed.
OBJECTIVES: Experimental studies using nanoscale TiO2 have documented lung injury, inflammation, oxidative stress, and genotoxicity. Human health data are extremely scarce. METHODS: In exhaled breath condensate (EBC) and urine of 22 office employees occupationally exposed to TiO2 during their visit in the production workshops for average 14±9 min/day a panel of biomarkers of nucleic acids and proteins oxidation was studied, specifically 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), 5-hydroxymethyl uracil (5-OHMeU), o-tyrosine (o-Tyr), 3-chlorotyrosine (3-ClTyr), and 3-nitrotyrosine (3-NOTyr). Examination was performed also in 14 comparable controls. RESULTS: The median respirable TiO2 mass concentration in the workshops was 0.40 mg/m3, median number concentration was 2.32×104 particles/cm3 with 80% of the particles being <100 nm in diameter. All 6 markers of oxidation were elevated in EBC in factory office employees relative to controls (p<0.01). Significant association was found between their job in TiO2 production plant and 5 markers of oxidation (except 3-NOTyr) in the EBC in multivariate analysis. No elevation of markers was detected in the urine. CONCLUSION: This pilot study suggests that even short nanoTiO2 exposure may lead to pulmonary oxidative stress; however this effect may be short-term and reversible. The clinical significance of these findings is unclear and more studies are needed.