IN-VIVO EVALUATION OF TIMING, DEGREE, AND DISTRIBUTION OF BACTERIAL TRANSLOCATION FOLLOWING EXPERIMENTAL SMALL-BOWEL TRANSPLANTATION

These studies were designed to evaluate the correlation between morpho logic and functional changes after heterotopic auxiliary small bowel i sograft with systemic venous drainage and two ostomies in 20 Lewis rat s. Morphologic damage of the graft was scored by full-thickness biopsi es before surgery and 1, 3, 5, and 7 days after transplant, Functional evaluation of the graft was done, at the same time points, by urinary excretion of lactulose and mannitol injected in the proximal ostomy, The intestinal permeability was also studied by injecting Escherichia coli labeled with indium-111 oxine in the proximal ostomy, Translocati on of radiolabeled bacteria was quantitated in extraintestinal tissues by radionuclide counts and number of viable organisms and in vivo by scintigraphic imaging. One day after transplant, significant graft dam age (score 17.2+/-4.2) was observed when compared with the pretranspla nt value (7.3+/-2.6). The degree of tissue injury was similar on days 3 (15.8+/-3.5) and 5 (16.1+/-3.9) after transplant and remained high o n day 7 (11.8+/-2.8). The lactulose to mannitol ratio showed a signifi cantly increased permeability on day 1 (17.5) versus pretransplant val ues (2.6), remained high on day 3 (8.6), and returned to normal values on day 5 (2.8), Translocation of bacteria to distant organs, as measu red by both radionuclide counts and number of viable organisms, was st rikingly enhanced on day 1 after transplantation, compared with contro l animals, but returned to the pretransplant value on day 3. A good qu alitative and quantitative correlation was observed between radionucli de counts in the extraintestinal organs and in vivo images obtained by scintigraphic scanning, In conclusion in this model, timing and degre e of bacterial translocation do not seem to correlate well, with the e xception of the acute posttransplantation phase, with morphologic and perme-ability changes of the graft, Evaluation of translocation by sci ntigraphic imaging appears a suitable approach to study in vivo the ki netics and distribution of this process.