Investigation of effects of Giardia duodenalis on transcellular and paracellular transport in enterocytes using in vitro Ussing chamber experiments.
The mechanisms by which different genotypes of Giardia duodenalis result in different symptoms remain unresolved. In particular, we lack detailed knowledge on which transport mechanisms (transcellular or paracellular) are affected by different Giardia isolates. Using horse radish peroxidase (HRP) and creatinine as transcellular and paracellular probes, respectively, we developed a robust assay that can be used with an Ussing chamber to investigate epithelial transport, as well as short-circuit current as an indicator of net ion transport. We investigated 2 Giardia isolates, both Assemblage A, one a lab-adapted strain and the other a field isolate. Results indicate that products from sonicated Giardia trophozoites increase both transcellular and paracellular transport. A non-significant increase in transepithelial electrical resistance (TEER) and short-circuit current were also noted. The paracellular transport was increased significantly more in the field isolate than in the lab-adapted strain. Our results indicate that while both transcellular and paracellular transport mechanisms may be increased following exposure of cells to Giardia trophozoite sonicate, perhaps by inducing non-specific increases in cellular traffic, it is important that in vitro studies of Giardia pathophysiology are conducted with different Giardia isolates, not just lab-attenuated strains.
Department of Food Safety and Infection Biology,Norwegian University of Life Sciences,PO Box 8146,N-0033 Oslo,Norway.
Kristoffer R
KR
Tysnes
Department of Food Safety and Infection Biology,Norwegian University of Life Sciences,PO Box 8146,N-0033 Oslo,Norway.
Lucy J
LJ
Robertson
D018938:Caco-2 Cells; D003404:Creatinine / Q000378:metabolism; D004594:Electrophysiology; D020895:Enterocytes / Q000378:metabolism* / Q000469:parasitology*; D004797:Enzyme-Linked Immunosorbent Assay; D005838:Genotype; D016829:Giardia lamblia / Q000145:classification / Q000235:genetics / Q000502:physiology*; D006735:Horseradish Peroxidase / Q000378:metabolism; D006801:Humans; D017136:Ion Transport; D010539:Permeability; D057900:Transcytosis / Q000502:physiology*
D003404:Creatinine; D006735:Horseradish Peroxidase
ELISA