Comparative assessment of small intestinal and colonic permeability in HIV-infected homosexual men.

Objectives: To investigate both small and large intestinal permeability in HIV-positive subjects, and correlate variation in intestinal mucosal abnormality with immunological and nutritional markers of HIV disease.
Methods: Small and large intestinal permeability studies were performed in 14 HIV-seropositive patients and eight healthy men. Eight out of the 14 patients had diarrhoea and all subjects were negative for enteropathogens. Small intestinal permeability was determined using the lactulose-mannitol test and large intestinal permeability using the colonic absorption of 51Cr-EDTA. In addition, CD4 cell count, beta 2-microglobulin, C-reactive protein estimation and anthropometry were carried out in all subjects.
Results: HIV-seropositive subjects had higher lactulose-mannitol ratios (LMR; 0.084 +/- 0.007 versus 0.013 +/- 0.0008) and lower 51Cr activity (1.986 +/- 0.066 versus 3.115 +/- 0.560) than controls (P < 0.0004 and P < 0.05, respectively). Colonic uptake of 51Cr-EDTA was no different between subjects with and those without diarrhoea (2.04 +/- 0.124 versus 1.92 +/- 0.143, P > 0.05). A negative correlation was found between LMR and 51Cr-EDTA, but only for patients with diarrhoea (r = -0.81; P = 0.015).
Conclusion: Regional variation affecting intestinal absorptive function occurs in patients with HIV-related diarrhoea and is characterized by increased LMR and reduced colonic uptake of 51Cr-EDTA. The pathogenesis and clinical significance of such changes are unknown.