Composition of clogging material in pancreatic endoprostheses

Area of Science:

• Gastroenterology
• Biomaterials Science
• Medical Device Engineering

Background:

• Endoscopic management of chronic pancreatitis (CP) has advanced, but rapid pancreatic stent occlusion limits clinical success.
• Understanding the mechanisms and materials causing stent occlusion is crucial for improving treatment outcomes.

Purpose of the Study:

• To investigate the composition and mechanisms of pancreatic stent occlusion in patients with CP.
• To identify the proteinaceous and inorganic components contributing to stent blockage.

Main Methods:

• Analysis of clogging material from 50 explanted pancreatic stents using protein solubilization, SDS-PAGE, Western blot, and mass spectrometry.
• Examination of insoluble components via polarized light microscopy and Periodic Acid-Schiff (PAS) staining.
• Gravimetric analysis of clogging material and correlation with stent and patient parameters.

Main Results:

• Clogging material was present in 49 of 50 stents, primarily at the duodenal flap (80%).
• Identified components included plant debris (80%), crystals (73.5%), mucopolysaccharides (100%), and calcium carbonate calculi (over a third).
• Dry weight of clogging material correlated with stent diameter (p=0.029); identified proteins included albumin, its degradation products, and lithostathine.

Conclusions:

• Pancreatic stents frequently accumulate occluding material, mainly at the duodenal flap.
• The occluding material consists of plant matter, mucopolysaccharides, crystals, and calcium carbonate.
• Albumin and lithostathine are implicated as significant contributors to pancreatic stent occlusion in CP.