Histopathological and immunohistochemical study of the hepatic lesions experimentally induced by Entamoeba dispar

Abstract

The sequence of hepatic necrotic-inflammatory events produced by Entamoeba dispar are originally described in this work. For the first time the experimental lesions produced by E. dispar were described in details, as well as the distribution of the trophozoites detected by the immunohistochemistry. Animals experimentally infected with E. dispar presented necrosis, thrombosis and chronic granulomatous inflammation. Immunoreactive products derived from trofozoites were observed close or associated with trophozoites, epithelioid cells, leucocytes and hepatocytes. Few are the articles on the literature about virulence of E. dispar, which is approximately 9 times more frequent than to Entamoeba histolytica (E. histolytica). Variation in the virulence is therefore expected and signalizing the need of the continuity of studies with E. dispar strains from different places in the world. Taking into account that E. dispar is a closely related species to E. histolytica, these studies could determine new elements involved with E. histolytica pathogenesis, helping us to better understand the disease.

Development of different diagnostic techniques for Endolimax piscium (archamoebae) and their applicability in Solea senegalensis clinical samples

“…Costa et al . pointed out the induction of apoptosis by E. histolytica , through direct activation of the host cells distal apoptotic machinery. However, the liver parenchyma destruction seems related to the extensive lysis of inflammatory cells through release of their cytotoxic granules rather than to the direct effect of the amebae on the hepatocytes (Tsutsumi et al .…”

“…The route of E. piscium to breach through the intestinal barrier reaching other organs is still not completely understood. In the case of E. histolytica, the intestinal infection varies from asymptomatic colonization to severe invasive infections (Costa et al 2010) and may even produce liver necrosis with slow expansion (amoebic liver abscess), with eventual progression to contiguous viscera. An haematogenous dissemination through the portal vein is the most commonly accepted route of liver invasion from the large intestine used by E. histolytica trophozoites, which can also reach other organs (left lung, brain and pericardium) (P erez-Tamayo 1986; Costa et al 2010).…”

“…In the case of E. histolytica, the intestinal infection varies from asymptomatic colonization to severe invasive infections (Costa et al 2010) and may even produce liver necrosis with slow expansion (amoebic liver abscess), with eventual progression to contiguous viscera. An haematogenous dissemination through the portal vein is the most commonly accepted route of liver invasion from the large intestine used by E. histolytica trophozoites, which can also reach other organs (left lung, brain and pericardium) (P erez-Tamayo 1986; Costa et al 2010). E. piscium stages were found not only within the intestinal epithelium and inner layers of the submucosa, but also in the pericardial membrane and the connective tissue between muscle fibres and other organs.…”

“…The mechanisms related to the progression of the lesion are unknown, but some authors suggested that the destruction of E. histolytica trophozoites could promote the consequent release of toxic products and/or enzymes that would contribute to the increase of necrosis and stimulate the development of the granuloma (Rivero-Nava et al 2002;Costa et al 2007). Costa et al 2010 pointed out the induction of apoptosis by E. histolytica, through direct activation of the host cells distal apoptotic machinery. However, the liver parenchyma destruction seems related to the extensive lysis of inflammatory cells through release of their cytotoxic granules rather than to the direct effect of the amebae on the hepatocytes (Tsutsumi et al 1984;Tsutsumi & Mart ınez-Palomo 1988;Mart ınez-Palomo et al 1989, Shibayama et al, 1998.…”

Immunocytochemistry Improving the Diagnosis ofTrichomonas vaginalisInfections

“…The production of the polyclonal anti- T. vaginalis antibody followed a protocol previously described [20] with some modifications. Briefly, 1 × 10 7 trophozoites of T. vaginalis (VPFS strain) were concentrated by centrifugation.…”