Limited efficiency of prolyl-endopeptidase in the detoxification of gliadin peptides in celiac disease.
OBJECTIVE
The resistance of prolamines to digestive enzymes is thought to be a key contributor to the pathogenesis of celiac disease by promoting the intestinal entrance of peptides able to trigger inflammation in at-risk individuals. Oral administration of a bacterial prolyl-endopeptidase (PEP) therefore was proposed as a treatment for celiac disease. To delineate the feasibility of this treatment, the effect of PEP on gliadin peptides was assessed in vitro, and ex vivo during their transport across intestinal biopsy specimens of active celiac disease patients.


METHODS
In vitro degradation by PEP of 3H-labeled gliadin peptides 56-88 (33-mer) and 31-49, was analyzed by radio-reverse-phase high-performance liquid chromatography and mass spectrometry. For ex vivo studies, PEP and 3H-peptides were added together onto the mucosal side of duodenal biopsy specimens mounted in Ussing chambers, and peptide transport and digestion were assessed by radio-reverse-phase high-performance liquid chromatography.


RESULTS
Gliadin peptides were degraded partly by 20 mU/mL PEP both in vitro and ex vivo. This concentration of PEP decreased the amount of intact peptides 31-49 and 56-88 crossing the intestinal biopsy specimens of celiac disease patients, but could not prevent the intestinal passage of toxic or immunostimulatory metabolites. PEP concentrations of at least 500 mU/mL for 3 hours were required to achieve full detoxification of peptides and to prevent intestinal transport of active fragments.


CONCLUSIONS
After prolonged exposure to high concentrations of PEP, the amount of immunostimulatory gliadin peptides reaching the local immune system in celiac patients is decreased. These results provide a basis to establish whether such conditions are achievable in vivo.
Matysiak-Budnik
Tamara
T
INSERM EMI-0212, Faculté Necker-Enfants Malades, Paris, France. matysiak@necker.fr
Candalh
Celine
C
Cellier
Christophe
C
Dugave
Christophe
C
Namane
Abdelkader
A
Vidal-Martinez
Teresita
T
Cerf-Bensussan
Nadine
N
Heyman
Martine
M
D001706:Biopsy; D002446:Celiac Disease / Q000188:drug therapy* / Q000473:pathology; D002851:Chromatography, High Pressure Liquid; D005903:Gliadin / Q000493:pharmacokinetics / Q000633:toxicity*; D008658:Inactivation, Metabolic; D007553:Isotope Labeling; D013058:Mass Spectrometry; D009842:Oligopeptides / Q000493:pharmacokinetics; D000085822:Prolyl Oligopeptidases; D012697:Serine Endopeptidases / Q000627:therapeutic use*; D014316:Tritium
D009842:Oligopeptides; D014316:Tritium; D005903:Gliadin; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases