Methylhexahydrophthalic anhydride adducted albumin tryptic peptides in nasal lavage fluid

Abstract

Methylhexahydrophthalic anhydride (MHHPA) is a reactive, low molecular weight chemical used in products such as plastics, paints, and electronic components. Exposure to MHHPA may lead to work-related airway diseases such as rhinitis, conjunctivitis, and asthma. Twelve subjects employed at a plant manufacturing electrical capacitors using MHHPA were included in this study. Nasal lavages were collected from subjects before work Monday morning and after work Tuesday afternoon. The levels of MHHPA adducted to serum albumin were analyzed with a straightforward work-up method. The samples were trypsinated before being analyzed with a liquid chromatography–triple quadrupole mass spectrometer. The mass spectrometer was run using selected reaction monitoring for six adducted peptides. Also, some biomarkers of effect (albumin, total protein, eosinophil cationic protein, and tryptase) were analyzed in nasal lavages. Furthermore, the metabolite MHHP acid in urine after work on Tuesday was analyzed by gas chromatography–mass spectrometry. Symptoms from the airways and the eyes and sensitization were registered. The main result of this study is that protein adducts can be analyzed in vivo after low occupational exposures to MHHPA. The results also show a correlation between adducted peptides and albumin in nasal lavage. Furthermore, there may be a difference in the potential to induce hyperresponsiveness between adducts bound to different amino acids.

Keywords::

• Methylhexahydrophthalic anhydride
• tryptic peptides
• biomarkers
• adducts
• nasal lavage fluids
• mass spectrometry
• human serum albumin

Acknowledgements

We thank Helene Ottosson and Birgitta Björk for skillful technical assistance, and Inger Bensryd for the collection of samples. Funding for the study was obtained from the Swedish Council for Work Life Research, the Swedish Research Council, the EU Network of Excellence ECNIS (www.ECNIS.org), the AFA Foundation, and the Medical Faculty at Lund University, Sweden.