Analyses of human colonic mucus obtained by an in vivo sampling technique.
BACKGROUND
The mucus layer is an important dynamic component of the epithelial barrier. It contains mucin glycoproteins and other compounds secreted by the intestinal epithelium, such as secretory IgA. However, a standardized in vivo sampling technique of mucus in humans is not yet available.


OBJECTIVE
To assess the validity and feasibility of mucin and protein determinations in human colonic mucus collected under physiological conditions.


METHODS
Triplicate colonic mucus samples were collected in 11 healthy volunteers using cytology brushes during sigmoidoscopy. As an indication of the quantity of collected mucus, total protein and mucin concentrations were determined by measuring oligosaccharide equivalents and monosaccharides. Also secretory IgA and sialic acid concentrations were determined and proteomic analysis was performed using surface enhanced laser desorption/ionization-time of flight-mass spectrometry.


RESULTS
Mean values of secretory IgA and sialic acid corrected for the amount of mucus ranged from 0.16 to 1.81 g secretory IgA/mmol oligosaccharide equivalents and from 12.6 to 48.6g sialic acid/mmol oligosaccharide equivalents. Proteomic analysis of mucus is feasible and cluster analysis showed subject specific profiles.


CONCLUSIONS
Using cytology brushes, human colonic mucus can be sampled and under physiological conditions. These samples could give information on the composition and quality of the mucus layer.
Hamer
H M
HM
TI Food and Nutrition, Wageningen, The Netherlands. H.Hamer@intmed.unimaas.nl
Jonkers
D M A E
DM
Loof
A
A
Vanhoutvin
S A L W
SA
Troost
F J
FJ
Venema
K
K
Kodde
A
A
Koek
G H
GH
Schipper
R G
RG
van Heerde
W L
WL
Brummer
R J
RJ
D000293:Adolescent; D000328:Adult; D003106:Colon / Q000378:metabolism*; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009005:Monosaccharides / Q000032:analysis; D009077:Mucins / Q000032:analysis; D009093:Mucus / Q000737:chemistry*; D019158:N-Acetylneuraminic Acid / Q000032:analysis; D009844:Oligosaccharides / Q000032:analysis; D011506:Proteins / Q000032:analysis; D012812:Sigmoidoscopy; D013048:Specimen Handling / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D055815:Young Adult
D007071:Immunoglobulin A, Secretory; D009005:Monosaccharides; D009077:Mucins; D009844:Oligosaccharides; D011506:Proteins; D019158:N-Acetylneuraminic Acid