Evaluation of the Local Immune Response to Hydatid Cysts in Sheep Liver

Comparative analysis of host immune responses to Hydatid cyst in human and ovine hepatic cystic Echinococcosis

BACKGROUND

Hydatid disease is caused by the larval stages of the canine tapeworm Echinococcus granulosus. It is one of the most critical helminthic diseases, representing worldwide public health and socio-economic concern.

AIM

This study aimed to investigate the expression of apoptosis and immune response within hepatic tissues of humans and sheep infected with the Hydatid cyst.

METHODS

Paraffin-embedded tissue was prepared from each tissue sample and used for histopathological examination by Haematoxylin- Eosin. Also, toluidine blue staining was used for mast cell detection, while an immunohistochemical study was performed to assess CD3 T lymphocytes, CD4 helper T lymphocytes, CD8 cytotoxic T lymphocytes, CD20 memory B lymphocytes, CD68 macrophage, and caspase-3 antibodies.

RESULTS

The histological examination revealed significant changes, including the infiltration of inflammatory cells, predominantly lymphocytes with scattered giant cells, necrotic hepatic tissue, and fibrosis. Toluidine blue stain revealed a higher number of mast cells (5 cells/field) in humans compared to sheep (3.6 cells/field). The immunohistochemical analysis confirmed that the CD3 were the most predominant inflammatory cell in the hepatic tissue of humans (intensive 70%), and sheep (moderate 38.47%). Caspase-3 was observed in all samples in different grades and mostly in human liver tissue.

CONCLUSION

This data could aid in recognizing immunological markers for differentiating disease progression, as well as enhance the understanding of local immune responses to cystic Echinococcosis (CE). The findings could provide preliminary data for future studies on immune responses associated with Hydatid cysts.

Potential use of silver nanoparticles green synthesized using Astragalus spinosus extract for treating cystic echinococcosis

The present investigation aims to develop and evaluate silver nanoparticles (AgNP) synthesized through environmentally friendly methods and to assess their effectiveness against hydatid cysts through in vitro, ex vivo, and in vivo experiments. The green synthesis of ANP was accomplished using the precipitation technique with Astragalus spinosus extract. The in vitro protoscolicidal effects of ANP were evaluated on hydatid cyst protoscoleces (PTS) through eosin exclusion test. The study also investigated the effect of ANP on the gene expression levels of caspase-3 and 9, as well as the external morphology of PTS. The in vivo efficacy was assessed by analyzing the quantity, dimensions, and weight of hydatid cysts in infected mice. Real-time PCR was used to analyze the gene expression levels of antioxidant and inflammatory cytokines. ANP exhibited significant (p < 0.001) in vitro protoscolicidal activity in a dose- and time-dependent manner. Treatment with ANP resulted in creases and protrusions on the plasma membrane, indicating bleb formation and an increase in the expression of caspase-3 and caspase-9 genes. Notably, there was a significant (p < 0.001) reduction in the number, size, and weight of hydatid cysts following ANP treatment. Administration of ANP resulted in a significant increase in the expression of antioxidant genes (glutathione peroxidase and superoxide dismutase) and a notable decrease in oxidative stress markers, as well as in the expression levels of Interleukin-4 (IL-4) and IL-10. Due to its antioxidant and anti-inflammatory properties, ANP shows potential as a scolicidal agent and holds promise in managing hydatid cysts in a mouse model. Nevertheless, further clinical trials are imperative to validate the efficacy of ANP in treating hydatidosis.

Evaluation of the Local and Peripheral Immune Responses in Patients with Cystic Echinococcosis

BACKGROUND

Cystic echinococcosis (CE) cysts may persist for decades because of immune modulation mechanisms. Here, we characterize the cysts and the blood immune responses in patients with CE.

METHODS

We enrolled 61 patients with CE and 19 control subjects. We received tissue samples from seven patients with CE and a control subject requiring liver cystectomy. The immunohistochemistry evaluation of the immune cell subtypes and cytokines in the pericysts and surrounding liver and the antigen B (AgB)-specific response analysis of whole blood were performed.

RESULTS

In CE, the pericyst and the surrounding liver parenchyma showed aggregates of CD3+ T lymphocytes, mainly CD4+. B lymphocyte aggregates were present in the liver tissue. Monocytes/granulocytes were rarely observed. Th2 cytokine expression was scarce, whereas IFN-γ expression was present in the CE tissues. The control subject did not show an inflammatory infiltrate. The IL-4-specific response to AgB was increased in the patients with CE compared to the control, and this result was confirmed in a larger cohort (p = 0.003), whereas the IFN-γ-response was similar between the two groups (p = 0.5570).

CONCLUSION

In patients with CE, CD4+ lymphocytes infiltrate the pericyst and the surrounding liver tissue with a low IL-4/IL-13 expression level and a moderate IFN-γ expression level; moreover, an IL-4 parasite-specific response is detected in the periphery. These results support adventitia involvement in CE immunopathogenesis.

Characterization of the immunosuppressive environment induced by larval Echinococcus granulosus during chronic experimental infection

The larval stage of Echinococcus granulosus causes the chronic infection known as cystic echinococcosis, deploying strong inhibitory mechanisms on host immune responses. Using experimental intraperitoneal infection in C57BL/6 mice, we carried out an in-depth analysis of the local changes in macrophage populations associated with chronic infection. In addition, we analyzed T cells and relevant soluble mediators. Infected animals showed an increase in local cell numbers, mostly accounted for by eosinophils, T cells, and macrophages. Within macrophage populations, the largest increases in cell numbers corresponded to resident large peritoneal macrophages (LPM). Monocyte recruitment appeared to be active, as judged by the increased number of monocytes and cells in the process of differentiation towards LPM, including small (SPM) and converting peritoneal macrophages (CPM). In contrast, we found no evidence of macrophage proliferation. Infection induced the expression of M2 markers in SPM, CPM, and LPM. It also enhanced the expression of the co-inhibitor PD-L1 in LPM, SPM, and CPM and induced the co-inhibitor PD-L2 in SPM and CPM. Therefore, local macrophages acquire M2-like phenotypes with probable suppressive capacities. Regarding T cells, infection induced an increase in the percentage of CD4+ cells that are PD-1+, which represent a potential target of suppression by PD-L1+/PD-L2+ macrophages. In possible agreement, CD4+ T cells from infected animals showed blunted proliferative responses to in vitro stimulation with anti-CD3. Further evidence of immune suppression in the parasite vicinity arose from the observation of an expansion in FoxP3+ CD4+ regulatory T cells and increases in the local concentrations of the anti-inflammatory cytokines TGF-β and IL-1Ra.