TEMPORAL CHANGES IN PERMEABILITY AND STRUCTURE OF PIGLET ILEUM AFTER SITE-SPECIFIC INFECTION CRYPTOSPORIDIUM-PARVUM

Background/Aims: Cryptosporidiosis is an important enteric infection a ssociated with diarrhea in humans. The structural and-functional basis for diarrhea is poorly understood. The aim of the study was to determ ine the structural and functional basis of diarrhea in cryptosporidios is during evolving host cell-parasite interactions in the intestine, M ethods: We used the piglet model for temporal studies of alterations i n intestinal epithelial structure and function that occurred 12-48 hou rs postinoculation, Segments of intestine were directly inoculated in vivo, harvested, and studied in vitro using Ussing chamber techniques, Results: Villus architectural alterations corresponded to the extent of infection. Increased numbers of lamina propria inflammatory cells w ere evident at 36 hours postinoculation. Solute and macromolecular per meability was not increased, Glucose-responsive short-circuit current was diminished at 48 hours postinoculation. The short-circuit current response to phlorizin was attenuated, The short-circuit current respon se to theophylline was the;same in control and infected tissues, Concl usions: We conclude that passive solute and macromolecular permeabilit y in infected tissues is not significantly increased during parasite-h ost cell interactions 12-48 hours postinoculation. Electrogenic glucos e stimulated Na+ absorption, a function principally of villus absorpti ve cells, is impaired, and electrogenic Cl- secretion, a function of c rypt epithelial cells, remains the same, These findings parallel struc tural observations that include loss of the Na+/glucose-transporting v illus epithelium without loss of crypt epithelium.