Cellular membrane associated mucins in artificial urine as mediators of crystal adhesion: an in vitro enterocystoplasty model.
OBJECTIVE
Cells are a major component of mucus in enterocystoplasties. We evaluate the role of secreted mucins on cells and cellular membranes as crystal adhesion and agglomeration mediators in artificial urine infected with Proteus mirabilis.


METHODS
Five human intestinal cell lines, HT29, HT29-18N2, HT29-FU, HT29-MTX, Caco-2 and 1 ureter cell line, SV-HUC-1, were incubated for 3 hours in artificial urine with P. mirabilis (ATCC49565) in monolayer and scraped conditions. We isolated Triton X-100 soluble membrane proteins from cells to evaluate the effect of MUC2 and MUC 5AC as membrane associated proteins on crystal formation and crystal adherence. Scanning electron microscopy, light microscopy, Coulter Counter measurements and x-ray microanalysis were used to evaluate crystal formation.


RESULTS
Brushite crystals were adhered to cellular surface sites rich in sulfur as crystal agglomerates. Smaller and more numerous crystals were observed in the presence of scraped cells. Crystal growth and agglomeration was inhibited by the presence of MUC 5AC, whereas MUC2 had the opposite effect. Both are present on cellular membranes and are rich in sulfur. Cellular invasion by bacteria occurred in all cell lines.


CONCLUSIONS
Membrane associated cellular secretions such as MUC2 and 5AC are important crystal adhesion molecules on cells and have a clear effect on urease induced crystallization in vitro. MUC2 and MUC 5AC induce crystal adhesion and mucin type dependent effects on crystal agglomeration. The effects of MUC2 and MUC 5AC may explain the high incidence of bladder calculi in enterocystoplasties and emphasize the role of cellular surfaces in urine.
Mathoera
R B
RB
Department of Pediatric Urology, Erasmus University Rotterdam, The Netherlands.
Kok
D J
DJ
Visser
W J
WJ
Verduin
C M
CM
Nijman
R J
RJ
D002448:Cell Adhesion / Q000502:physiology*; D002462:Cell Membrane; D002478:Cells, Cultured; D006801:Humans; D007422:Intestines / Q000166:cytology*; D009077:Mucins / Q000502:physiology*; D014513:Ureter / Q000166:cytology*; D014556:Urine
D009077:Mucins