Destructive effect of gamma irradiation on Echinococcus granulosus metacestodes

Apoptosis as a Potential Target to Arrest and Survival of Hydatid Cyst

Background

Hydatidosis is a serious and life-threatening disease that may lead to the death of the host if diagnosed and treated improperly. Apoptosis has been investigated as a mechanism of host innate immunity in suppressing parasites and also the survival of cysts in the human body. The present study investigates the process and role of apoptosis caused by a host cell or parasite in hydatid cysts.

Materials and Methods

Survey cytotoxic effect and apoptotic mortality of hydatid-treated lymphocytes were investigated. Also, to determine the mechanism of apoptosis in host and parasite, the mean gene expressions of Bcl-2, Bax, Caspase 3 in hydatid-treated lymphocytes, and Fas-L gene in the laminated-germinal layer of fertile and infertile hydatid cysts were evaluated.

Results

The viability of fertile and infertile hydatid fluid-treated lymphocytes was significantly different compared with the control group. Flow cytometry also showed apoptotic cells. Bax mean gene expression was significantly different between fertile and infertile treated lymphocytes. However, there was no significant difference in the mean expression of Caspase 3, and Bcl-2 genes in these two groups. Although the expression of the Fas-L gene in infertile cysts was higher than in fertile cysts, the result was not significant.

Conclusion

It seems that hydatid cyst fluid may induce apoptosis in lymphocytes so that, hydatid cysts can escape from the immune system and stay alive. On the other hand, the results represent the possible immune path of host apoptosis against the parasite as one of the important routes in infertility of hydatid cysts.

Anti-hydatidosis Potential of Sodium Valproate: Evaluating New Therapeutic Potential for Sodium Valproate

Background: Larval stage of Echinococcus granulosus is the main cause of the hydatid cyst. Surgery, which is both aggressive and high-risk, is the most common treatment for this type of cyst. Some medicines, such as mebendazole, are also used as a complementary approach to preventing the recurrence of hydatid cysts. Objectives: Considering the approved antiparasitic effects of sodium valproate (VPA) on some parasites, this research intended to examine the potential of VPA against protoscolices and hydatid walls. Methods: Liver hydatid cysts caused by E. granulosus were collected from a slaughterhouse. Protoscolices and hydatid cysts were exposed to RPMI and dimethyl sulfoxide (DMSO) media (control groups) or different concentrations of VPA and mebendazole in vitro. The viability of protoscolices was evaluated via light microscopy. Also, tissue changes and expression of apoptotic caspase-3 were examined in hydatid cyst walls (HCWs) using histological and immunohistochemical methods, respectively. Results: The mortality rates of VPA-treated and mebendazole-treated protoscolices were dose- and time-dependent. There was a significant difference between the intervention and control groups (P < 0.05). Tissue changes and apoptosis were observed in VPA-treated and mebendazole-treated HCWs. Conclusions: Valproate and mebendazole had significant effects on protoscolices and HCWs, although VPA exerted its effects more rapidly. It seems that VPA can be a new promising protoscolicidal agent and anti-hydatid medicine.

Anti-parasitic effects of resveratrol on protoscolices and hydatid cyst layers

The main goal of the current study was to evaluate the effectiveness of resveratrol (RESV) on protoscolices and hydatid cysts of Echinococcus granolosus. Echinococcus granolosus protoscolices and hydatid cyst were exposed to RPMI, DMSO, formalin, mebendazole, and different concentrations of RESV in vitro. Then, viability, GGT, and caspase-3 activity of protoscolices were evaluated using light microscopy, colorimetric, and enzymatic assay, respectively. Tissue changes and expression of caspase-3 apoptosis were analyzed on the hydatid cyst wall by histologic and immunohistochemistry methods. The cell toxicity effect of RESV was evaluated on mouse PBMCs by Annexin V-FITC assay. The RESV-treated protoscolices showed loss of viability, increased gamma-glutamyl transpeptidase, and caspase-3 activity with significant differences compared to all control groups (P < 0.05). Dose and time dependence of mortality, GGT, and caspase-3 enzymatic activity was confirmed in the protoscolices of Echinococcus granulosus treated by RESV. Also, the tissue changes and apoptosis were prominent in RESV-treated hydatid cyst layers; however, tissue changes were only time-dependent, and RESV concentration had no apparent effect on tissue. In cell toxicity evaluation, RESV is safe without any significant apoptosis induction from 31.5 to 250 μg/ml; however, it was significant at 350 and 500 μg/ml in PBMCs.

Status and prospect of novel treatment options toward alveolar and cystic echinococcosis

Cystic echinococcosis (CE) and alveolar echinococcosis (AE) are the two most important global parasitic infectious diseases caused by species of Echinococcus granulosus and E. multilocularis, respectively. Although numerous trials have been performed in search of novel therapeutic options to curb the neglected zoonosis, no other nonsurgical options are currently available to replace the licensed anti echinococcal drugs albendazole (ABZ) and mebendazole (MBZ). A safer and more effective treatment plan for echinococcosis is therefore urgently needed to compensate for this therapeutic shortfall. Here, we present a review of the literature for state-of-the-art valuable anti-parasitic compounds and novel strategies that have proved effective against CE and AE, which includes details about the pharmaceutical type, practical approach, experimental plan, model application and protoscolecidal effects in vivo and in vitro. The content includes the current application of traditional clinical chemicals, the preparation of new compounds with various drug loadings, repurposing findings, combined programs, the prospects for Chinese herbal medicines, non-drug administrations and the exploration of target inhibitors based on open-source information for parasitic genes. Next the conventional experimental projects and pharmacodynamic evaluation methods are systematically summarized and evaluated. The demands to optimize the construction of the echinococcosis model and improve the dynamic monitoring method in vivo are also discussed given the shortcomings of in vivo models and monitoring methods.

Evaluation of the Apoptotic and Scolicidal Effects of Crude and Flavonoid Extracts of Allium noeanum on Protoscolices and Hydatid Cyst Wall

Background: Hydatidosis is a disease, caused by the larval phase of Echinococcus granulosus. It is considered a serious condition, as cyst rupture can release protoscolices into the host body, leading to the formation of secondary cysts. Surgery is the main approach for the treatment of this disease. Some natural compounds, which are safe options with few side effects, have been assessed for their scolicidal activities. Objectives: Allium noeanum is a native herb of Markazi Province, Iran, which has been used for the traditional treatment of certain diseases. However, its anti-parasitic property has not been investigated so far. The present study aimed to evaluate the anti-parasitic property of this plant by evaluating the scolicidal and apoptotic effects of two types of this herbal extract (crude and flavonoid) on hydatid cysts. Methods: The hydatid cysts were obtained from abattoirs, and protoscolices were drained under sterile conditions. The protoscolices suspension and cyst walls were used for scolicidal and immunohistochemical evaluations. In addition, A. noeanum was collected from Shazand Mountains. The crude and flavonoid extracts of this plant were prepared by maceration and chromatography methods, respectively. Immunohistochemistry was conducted for the detection of caspase-3 activity using a commercial kit. Data were analyzed in Excel and SPSS, and statistical significance was defined as P < 0.05. Results: The 100% concentration (0.49 gr/mL) of the crude A. noeanum extract caused the death of 100% of protoscolices. On the other hand, all concentrations of the flavonoid extract led to the death of 100% of parasites. According to the statistical analyses, each type of the extract showed different dose- and time-dependent rates of scolicidal activity (P < 0.001). Immunohistochemistry showed lower caspase-3 activity in cyst walls exposed to flavonoids, compared to those exposed to the crude extract. Conclusions: In the present study, the scolicidal activity of the flavonoid extract of A. noeanum against protoscolices was confirmed. It was also found that the apoptotic effect of the crude extract of this herb was more than its flavonoid extract.

MicroRNA-365 promotes apoptosis in human melanoma cell A375 treated with hydatid cyst fluid of Echinococcus granulosus sensu stricto

Hydatid cyst fluid (HCF)-based therapeutics has experimentally targeted approaches for treating human cancer cell lines. MicroRNA-365 (miR-365) has been reported to be an important tumor suppressor miRNA in cancers. However, it remains unknown, how miR-365 plays a pivotal role in inducing apoptosis in HCF-treated cancer cells in vitro. The fertile/infertile HCF was aspirated from liver of infected sheep and in terms of molecular taxonomy was identified as G1 genotype of Echinococcus granulosus sensu stricto. A375 human melanoma cancer cells were cultured into two groups: fertile and infertile HCF-treated A375 cells. To assess the cytotoxicity of various concentrations of HCF on melanoma cells, cell viability was determined by using MTT assay. The IC50 value of HCF on A375 cells was determined 85 μg/mL. Caspase-3 enzymatic activity was evaluated by fluorometric assay in the HCF-treated melanoma cells. In addition, the mRNA expression of Bax, Bcl-2, Caspase-9 and miR-365 were determined by qRT-PCR. Findings of MTT assay showed that concentrations 85 μg/mL to 100 μg/mL of fertile HCF have the highest mortality (50%-52%) on A375 cells during 24 h. The fold change of Bax/Bcl-2 ratio, Caspase-9, miR-365 and Caspase-3 activity was higher in the fertile HCF-treated melanoma cells compared to infertile fluid treated A375 cells and human normal epithelial cell (as control cell). In conclusion, we over-expressed the miR-365 in melanoma A375 cells, via treatment of fertile HCF. Our findings suggested that inducing high expression of miR-365 might be a negative regulator of melanoma growth through activation of pro-apoptotic Bax, Caspase-9 and Caspase-3 that are essential to intrinsic apoptotic pathway. These findings provide new insights into the use of Echinococcus HCF-derived metabolites in the design of drug therapies and in vivo tumor cell vaccine to combat melanoma progression.

Study on the effect of an ion channel inhibitor "Fluralaner" on Echinococcus granulosus protoscolices and metacestode layers in vitro

Hydatid disease has a great impact on public health, causing high morbidity and mortality. Main lines of treatment include surgery, which mostly requires the installation of a scolicidal agent into hydatid cysts to prevent dissemination. Alternatively, medical treatment involves the use of benzimidazole drugs; however, the results are not satisfactory, and new drug compounds are urgently needed. Fluralaner is a potent inhibitor of GABA-gated chloride channels and L-glutamate-gated chloride channels (GluCls) providing immediate and persistent flea, tick and mite control in dogs after a single oral dose. Researches previously identified different genes encoding ion channels in Echinococcus granulosus, making ion channel inhibitors a promising target for treating hydatid disease. Thus, the present study aimed to evaluate the effect of fluralaner on protoscolices and metacestode layers. Parasite materials (Protoscolices, Metacestodes layers) were exposed to different concentrations of the drug ranging from "12.5-100 ug/ml" and examined for viability after 1, 6 and 24 h. Morphological and ultrastructural alterations were recorded by both light and electron microscopies. Immunohistochemical staining confirmed caspase-3 activation as an indicator of apoptosis- induced therapy. The treated protoscolices and metacestode layers showed loss of the viability, the formation of vacuoles and lipid droplets, separation of the germinal layer, and damage in the laminated layer; apoptosis was prominent after treatment. These findings revealed that fluralaner has a potent scolicidal activity and suggested its therapeutic potential against hydatid disease. Further evaluations for animals and human use in the treatment and prevention of hydatid disease are needed.

Recent advances on innate immune pathways related to host-parasite cross-talk in cystic and alveolar echinococcosis

Cystic echinococcosis (CE) and alveolar echinococcosis (AE) are life-threatening parasitic infections worldwide caused by Echinococcus granulosus (sensu lato) and E. multilocularis, respectively. Very little is known about the factors affecting innate susceptibility and resistance to infection with Echinococcus spp. Although benzimidazolic drugs against CE and AE have definitively improved the treatment of these cestodes; however, the lack of successful control campaigns, including the EG95 vaccine, at a continental level indicates the importance of generating novel therapies. This review represents an update on the latest developments in the regulatory functions of innate immune pathways such as apoptosis, toll-like receptors (TLRs), and inflammasomes against CE and AE. We suggest that apoptosis can reciprocally play a bi-functional role among the host-Echinococcus metabolite relationships in suppressive and survival mechanisms of CE. Based on the available information, further studies are needed to determine whether the orchestrated in silico strategy for designing inhibitors and interfering RNA against anti-apoptotic proteins and TLRs would be effective to improve new treatments as well as therapeutic vaccines against the E. granulosus and E. multilocularis.

Post-immunization immunohistochemical expression of Caspase 3 and p53 apoptotic markers in experimental hydatidosis

Abstract The aim of this study was to investigate post-immunization apoptotic changes in experimental hydatidosis, using Caspase 3 and p53 immunohistochemical markers. Two groups of rabbits were immunized with a crude antigen (group 1) or a partially purified antigen (group 2) and were compared to an infected non-immunized control group. More effective immune responses were obtained in group 2 than group 1, signified by fewer and smaller cystic lesions and more severe destructive changes. Normal growth of cysts was attained in the control group, with no expression of apoptotic markers. Significantly higher expression of Caspase 3 and p53 were observed in group 1 compared to group 2, as indicated by OD and area percentage, respectively (Group 1 Caspase 3: 0.89±0.21, 93.5%±6.2; Group 1 p53: 0.46±0.18, 53.26%±11.6; Group 2 Caspase 3: 0.52±0.15, 49.23%±11.7; Group 2 p53: 0.19±0.4, 18.17%±7.3). Vaccine-induced immune responses and cellular damage may underlie the expression of apoptotic markers that appeared to result in a degenerative and atrophic course of action upon immunization. The results of the current study emphasize the importance of immunization for the stimulation of protective immune responses and in preventing mechanisms of evasion to ensure normal cell growth. A cost/benefit control program that implements proper vaccine preparations should be further assessed for complete elimination of severe infections in endemic areas.