Ceramide is increased in the lower airway epithelium of people with advanced cystic fibrosis lung disease.
BACKGROUND
Ceramide accumulates in the airway epithelium of mice deficient in cystic fibrosis transmembrane conductance regulator, resulting in susceptibility to Pseudomonas aeruginosa infection and inflammation.


OBJECTIVE
To investigate quantitatively ceramide levels in the lower airway of people with cystic fibrosis compared with pulmonary hypertension, emphysema, and lung donors.


METHODS
Immunohistochemistry was performed on the lower airway epithelium of explanted lungs (eight cystic fibrosis, emphysema, and pulmonary hypertension, respectively) and eight donor lungs using ceramide, neutrophil elastase, and myeloperoxidase antibodies. High-performance liquid chromatography-mass spectrometry was performed on tissue from five lungs with cystic fibrosis and five with pulmonary hypertension.


RESULTS
Staining for ceramide was significantly increased in the lower airway epithelium of people with cystic fibrosis (median, 14.11%) compared with pulmonary hypertension (3.03%; P = 0.0009); unused lung donors (3.44%; P = 0.0009); and emphysema (5.06%; P = 0.01). Ceramide staining was increased in emphysematous lungs compared with pulmonary hypertension (P = 0.0135) and unused donors (P = 0.0009). The number of neutrophil elastase- and myeloperoxidase-positive cells in the airway was positively correlated with the percentage of epithelium staining for ceramide (P = 0.001). Ceramide staining was significantly increased in lungs colonized with Pseudomonas aeruginosa (10.1%) compared with those not colonized (3.14%; P = 0.0106). Significantly raised levels of ceramides C16:0, C18:0, and C20:0 were detected by mass spectrometry in lungs with cystic fibrosis compared with pulmonary hypertension. Differences in C22:0 were not significant.


CONCLUSIONS
Immunoreactive ceramide is increased in the lower airway epithelium of people with advanced cystic fibrosis. Detected by mass-spectrometry ceramide species C16:0, C18:0, and C20:0 but not C22:0 are increased.
Brodlie
Malcolm
M
Sir William Leech Centre For Lung Research, Freeman Hospital, Newcastle upon Tyne, UK. m.j.brodlie@ncl.ac.uk
McKean
Michael C
MC
Johnson
Gail E
GE
Gray
Joe
J
Fisher
Andrew J
AJ
Corris
Paul A
PA
Lordan
James L
JL
Ward
Christopher
C
D000293:Adolescent; D000328:Adult; D002518:Ceramides / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003550:Cystic Fibrosis / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000378:metabolism / Q000473:pathology; D007150:Immunohistochemistry; D019272:Leukocyte Elastase / Q000378:metabolism; D008168:Lung / Q000378:metabolism / Q000382:microbiology; D013058:Mass Spectrometry; D008875:Middle Aged; D009195:Peroxidase / Q000378:metabolism; D011550:Pseudomonas aeruginosa; D011656:Pulmonary Emphysema / Q000378:metabolism / Q000473:pathology; D020545:Respiratory Mucosa / Q000378:metabolism*; D012720:Severity of Illness Index
D002518:Ceramides; D009195:Peroxidase; D019272:Leukocyte Elastase