Table 4.
Means for the assessment of intestinal permeability (functional tests, bacteria-related tests)
| Means | Hu | An | Test molecules | Test site | Material needed | Disadvantages |
|---|---|---|---|---|---|---|
| Ex vivo | ||||||
| Ussing chamber | x | x | H2O, ions, sugars etc., | site specific | biopsies | invasive |
| In vivo – permeability assays | ||||||
| Lactulose/mannitol | x | x | oligosaccharides of different MW | small intestine | urine | time consuming |
| Sucralose | x | (x) | sucralose(comb.)* | colon | urine | time consuming |
| Sucrose | x | (x) | sucrose(comb.)* | stomach | urine | time consuming |
| PEG4000/400 | x | (x) | polyethylene glycols | whole intestine | urine | time consuming |
| 51Cr-EDTA | x | x | 51Cr-EDTA | whole intestine | urine | radio-activity |
| In vivo – bacteria-related | ||||||
| LAL assay | x | x | endotoxin (LPS) | whole intestine | plasma | assay limitation |
| EndoCAb | x | x | anti-LPS antibodies | whole intestine | serum | only in acute phase |
| D-lactate | x | x | bacterial lactate | whole intestine | plasma | low specificity |
| Butyrate production | x | x | BPB (PCR) | colon | feces | special labs, limited data |
| Hemolysin test | x | x | pathogens (cell culture) | colon | feces | special labs, limited data |
| Inner colon mucus | x | x | quantification of bacteria | colon | biopsies | invasive,limited standardization |
| Liver steatosis | x | x | fat content in the liver | whole intestine | MRT, US | expensive unspecific |
| Breath tests | x | x | fat content in the liver | whole intestine | GC/MS | unclear specificity |
Abbreviations: Hu suitable for the human system, An suitable for animal models, 51Cr-EDTA chromium labeled EDTA, BPB butyrate-producing bacteria, EndoCAb circulating endotoxin core antibodies, GC gas chromatography, LAL limulus amebocyte lysate assay, LPS lipopolysaccharide, MRT magnetic resonance tomography, MS mass spectroscopy, PEG polyethylene glycols, US ultrasound. *in combination with Lactulose/mannitol test.