Pathogenesis of intestinal amebiasis: From molecules to disease

In spite of a wealth of knowledge on the biochemistry and cellular and mole cular biology of Entamoeba histolytica, little has been done to apply these advances to our understanding of the lesions observed in patients with int estinal amebiasis. In this review the pathological and histological finding s in acute amebic colitis are related to the molecular mechanisms of E. his tolytica pathogenicity described to date. Infection of the human colon by E . histolytica produces focal ulceration of the intestinal mucosa, resulting in dysentery (diarrhea with blood and mucus). Although a complete picture has not yet been achieved the basic mechanisms involved in the production o f focal lyric lesions include complex multifactorial processes in which lec tins facilitate adhesion, proteases degrade extracellular matrix components , porins help nourish the parasite and may also kill incoming polymorphonuc lear leukocytes and macrophages, and motility is used by the parasite to in vade deeper layers of the colon. In addition E. histolytica has developed m echanisms to modulate the immune response during acute infection. Neverthel ess, much still needs to be unraveled to understand how this microscopic pa rasite has earned its well-deserved histolytic name.