Measurement of nerve growth factor in induced sputum and exhaled breath condensate

• Main Author: Nwiloh, Victor Maduabuchi
• Format: Others
• Published: Scholar Commons 2006
• Subjects: Asthma; Inflammatory; Allergic; Bronchoalveolar lavage; Noninvasive; American Studies; Arts and Humanities
• Online Access: http://scholarcommons.usf.edu/etd/2650; http://scholarcommons.usf.edu/cgi/viewcontent.cgi?article=3649&context=etd

Several tests are available for evaluation of respiratory disorders but most of them are invasive and associated with some risk or patient discomfort. Examples include bronchoscopy (bronchoalveolar lavage, BAL) [1], venopuncture [2] and sputum induction [3]. Noninvasive sampling of nongaseous substances contained in expired air, collected as exhaled breath condensate (EBC) has been used to detect inflammatory markers and by-products including nitric oxide and arachidonic acid metabolites and proteins [4]. Nerve growth factor (NGF) is a protein that has been implicated in neurogenic airway inflammation and this pilot study aimed to develop a non-invasive approach for evaluation of allergic airway inflammatory disease by measuring and comparing levels of NGF in the induced sputum and EBC of ten (10) asthmatics and ten (10) non-asthmatics.Though twenty (20) subjects were sampled, an unexpected event due to a defective NGF kit inadvertently resulted in an unsuccessful analysis of fifteen (15) sets of specimen (6 non-asthmatics and 9 asthmatics), limiting the study.This study is significant because occupational lung diseases are the number one work-related illness in the United States and occupational asthma is the most common form [9]. Toluene diisocyanate (TDI) is the commonest cause of occupational asthma and workers exposed to TDI vapor may develop inflammatory conditions including asthma, rhinitis and nasal irritation [7].Results: NGF was detected and measured only in sputum, with a mean NGF level of 210 (210-210, range 0) in asthmatics and 164 (7-280, range 273) in non-asthmatics. Nonetheless, we failed to reject the null hypothesis (number 3).Conclusion: This limited study did not have adequate power (power 11%) due to the small sample size and thus lacks internal validity. Further studies are needed using a larger sample size.