Evaluation of a possible role of tissue inhibitor of metalloproteinases 1 (TIMP-1) in the pathogenesis of hydatid disease.

Tissue inhibitor of metalloproteinases-1 (TIMP-1), in the serum levels of 27 patients was significantly higher and almost a double of that measured in healthy patients. Considerably higher TIMP-1 levels were recovered in patients with higher specific antibody titers and those with hepatic cysts in relation to low-titer patients and pulmonary cysts respectively, reflecting an immunologic dose-dependent and cell type-specific regulation of TIMP-1 production. Yet, these higher TIMP-1 levels stop short to be statistically significant in both groups. Patients with multi-sited hydatid cysts also show statistically insignificant higher TIMP-1 levels compared to single-sited cysts.

Modulation of the pathologic and apoptotic changes of experimental toxoplasmosis by concomitant infection with Trichinella spiralis.

This study shows that Toxoplasma gondii infection is capable of inducing a process of programmed cell death not only in the infected hepatocytes of experimental murine model, but also the neighbouring non-infected cells. However, some cells showed a possible mixed apoptotic and necrotic pattern. Surprisingly, lymphocytes and Kupffer cells in portal sinusoids nearby the parasite vacuoles showed no apparent changes. Toxoplasma in concomitant infection with a different parasite, Trichinella spiralis, clearly mitigate the pathologic and apoptotic changes caused by T. gondii. These findings might help in understanding the problematic biology and immunopathogenesis of T. gondii. The results also augments previous reports by the same authors about the possible protective role of heterologous antigens of one parasite against a biologically and immunologically different parasite.

Reciprocal heterologous protection between Trichinella spiralis and Toxoplasma gondii concurrently present in experimental murine models.

Mixed parasitic infections have been long seen as a double impact on the host. In this study a different view of polyparasitism is demonstrated. The influence of the immunological environments created by two biologically different parasites on the pathogenesis of each other was evaluated. Swiss albino mice were sequentially infected with the intracellular protozoan Toxoplasma gondii (acute and latent), which elicits a T-helper 1 (Th1)-polarized immune response and the helminth parasite Trichinella spiralis, whose infection is predominated by a Th2 response. The results show a significant heterologous protection from one parasite towards the other. There was a highly significant lower Trichinella muscle larvae burden in mixed infection group compared to single Trichinella infection, in spite of delayed intestinal adult worm expulsion in the mixed infection group. A highly significant lower burden of T. gondii brain cysts in mixed infection compared to single latent Toxoplasma infection was also demonstrated. Concerning the anti-Toxoplasma antibody response, there was a significant lower levels in the latent Toxo-Trich. group compared to the group of latent toxoplasmosis only. These significant lower antibody titers were reproducible by two different assays; dye test and direct agglutination test.