Protoscolicidal effects of chenodeoxycholic acid on protoscoleces of Echinococcus granulosus

An in vivo appraisal of Punica granatum peel extract's ultrastructural effect on cystic echinococcosis in mice

In the past decade, interest has significantly increased regarding the medicinal and nutritional benefits of pomegranate (Punica granatum) peel. This study examined the effects of using pomegranate peel extract (PGE) alone and in combination with albendazole (ABZ) on ultrastructural and immunological changes in cystic echinococcosis in laboratory-infected mice. Results revealed that the smallest hydatid cyst size and weight (0.48 ± 0.47mm, 0.17 ± 0.18 gm) with the highest drug efficacy (56.2%) was detected in the PGE + ABZ group, which also exhibited marked histopathological improvement. Ultrastructural changes recorded by transmission electron microscopy including fragmentation of the nucleus, glycogen depletion, and multiple lysosomes in vacuolated cytoplasm were more often observed in PGE + ABZ group. IFN-γ levels were significantly increased in the group treated with ABZ, with a notable reduction following PGE treatment, whether administered alone or in combination with ABZ. Thus, PGE enhanced the therapeutic efficiency of ABZ, with improvement in histopathological and ultrastructural changes.

Evaluation of structural changes of Echinococcus granulosus protoscoleces following exposure to different protoscolicidal solutions evaluated by differential interference contrast microscopy

The present study was aimed to assess the structural changes in protoscoleces of Echinococcus granulosus sensu stricto following exposure to different natural and chemical protoscolicidal agents using differential interference contrast (DIC)/Nomarski microscopy. Protoscoleces of sheep's liver cysts were collected aseptically. Individually, about 1000 protoscoleces were exposed to 0.5% silver nitrate, 20% hypertonic saline solution, 0.5% cetrimide solution and two different concentrations of garlic chloroformic extraction as well as phosphate-buffered saline (PBS). The protoscoleces viability was assessed using 0.1% eosin solution, and structural modifications in the protoscoleces were examined by DIC/Nomarski microscopy. The results revealed the degeneration of the tegument, disorganization of the hooks, and reduction of the size of the protoscoleces exposed to cetrimide, hypertonic sodium chloride, and silver nitrate. Furthermore, calcareous corpuscles became blurred and opaque and their numbers decreased in all the exposed samples except, those in PBS. The exposed protoscoleces to cetrimide and hypertonic sodium chloride solution showed extensive degeneration of the tegument and disorganization of the hooks. In the group exposed to 200 mg/ml chloroformic garlic extract, the protoscoleces' width decreased. The length, width, and number of calcareous corpuscles also decreased significantly in the silver nitrate-exposed protoscoleces. The study concludes that protoscoleces exposed to different solutions; cetrimide 0.5% and hypertonic sodium chloride 20% caused more pronounced structural changes in the exposed protoscoleces. These changes were well demonstrated by DIC microscopy and can be used as a supplementary tool to evaluate the effects of protoscolicidal agents.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12639-023-01632-4.

Natural history of Echinococcus granulosus microcyst development in long term in vitro culture and molecular and morphological changes induced by insulin and BMP-4

Introduction

Cystic echinococcosis (CE) caused by the cestode Echinococcus granulosus is a disease of worldwide public health and economic importance. The determinants and underlying cellular mechanisms of CE development and fate in intermediate hosts are largely unknown. Hormones and cytokines such as insulin and BMP-4 are the key players in the development, differentiation, and apoptosis. In this study, we evaluated the long term natural history of E. granulosus microcysts in an vitro setting and the molecular and morphological changes induced by the growth factors, insulin and BMP4 during the development of metacestode stage of E. granulosus.

Methods

E. granulosus protoscoleces were cultivated and the parasite development was followed in the long term mono-phasic culture for 105 days and the morphometric, molecular and immunohistochemical changes were evaluated, including the microcysts number and size, microcysts development and deformation rates as well as the markers of calcification (Alizarin Red staining) and apoptosis (BAX, BCL2, Caspase-3, Caspase-8 and TNF-α expression) in the microcysts. Also the biological, histological and molecular consequences of insulin and BMP-4 treatment on the parasite development were evaluated.

Results

Insulin and BMP-4 treatment of microcysts resulted in significant increase in microcyst formation, increased size, reduced apoptosis and deformation of the microcysts. Alizarin red staining of the microcysts treated with the insulin and BMP-4 confirmed that calcium deposition is significantly lower than the untreated microcysts. Also Alizarin Red staining and Immunohistochemistry of the microcysts indicates that calcium accumulation in deformed microcysts is higher than the normal ones on day 105. The microcysts began to wrinkle and the germinal layer was partially detached from the laminated layer on day 84.

Conclusion

Results of the present study suggest that the degenerative changes in hydatid cysts can be slowed down by insulin and BMP-4, indicating that cellular factors and host hormones could contribute to the longevity of hydatid cysts. Significant evidences are provided suggesting that the microcysts cultivated in vitro can undergo calcification and apoptotic processes similar to what have been observed in the natural hydatid infection in the intermediate hosts.

Antioxidant, Protoscolicidal, Hemocompatibility, and Antibacterial Activity of Nickel Oxide Nanoparticles Synthesized by Ziziphus spina-christi

Over the past several years, the greener fabrication of metal oxide nanoparticles has attracted significant attention due to their simplicity, eco-friendliness, availability, and nontoxicity. This paper focused on the fabrication of nickel oxide nanoparticles (NiO-NPs) using the leaf extract of Ziziphus spina-christi L. and evaluating its potential biological activities. The characterization of synthesized NiO-NPs was confirmed using ultraviolet–visible spectroscopy, field emission-scanning electron microscope, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Furthermore, protoscolicidal, antibacterial, and antioxidant activities and hemocompatibility of NiO-NPs were investigated. The findings revealed that the NiO-NPs were crystalline on nanoscale between 50- and 90-nm particle sizes. The NiO-NPs showed high scolicidal activity against Echinococcus granulosus. The viability of the treated protoscoleces exponentially decreased with an increase in the concentration of NiO-NPs. The NiO-NPs exhibited effective antibacterial activity against Escherichia coli and Staphylococcus aureus. NiO-NPs also possess a H2O2 scavenging activity in a dose-dependent manner. This study revealed that the Z. spina-christi L. leaf extract is an effective reducing and capping agent for the production of NiO-NPs; it showed critical biological properties. Moreover, NiO-NPs have a potent antioxidant activity and low toxicity on the erythrocytes and appear hemocompatible.

In vitro protoscolicidal effects of lithocholic acid on protoscoleces of Echinococcus granulosus and its mechanism

Surgery has been found to be the best choice of treatment for hydatidosis. However, leakage of cyst contents during surgery is the foremost reason for recurrence of hydatidosis. In this study, we investigated the in vitro efficacy of lithocholic acid (LCA) against Echinococcus granulosus protoscoleces. The protoscoleces were divided into a control group, an albendazole (ABZ) positive control group and LCA intervention groups at concentrations of 0.5, 1, 2, and 3 mmol/L and stained with 0.1% eosin for observation using an inverted microscope; the protoscolecal ultrastructure was examined with SEM and TEM; the activities of ROS, SOD, and caspase-3 were investigated using an ROS kit, SOD kit, and caspase-3 kit, respectively; the contents of HO-1 and NQO-1 were analyzed by enzyme-linked immunosorbent assay; and the expression level of cytochrome c (Ctyc) was analyzed by western blotting. Results: As the concentration of LCA increased, the survival rate of protoscoleces gradually decreased. The microstructure shows that the external shape and internal structure were gradually deformed and collapse. SOD, GSH, HO-1 and NQO-1 decreased more significantly in the 3 mmol/L LCA group. However, ROS levels gradually increased. LCA treatment for 3 days at all concentrations significantly increased caspase-3 activity and expression in a dose-dependent manner. LCA decreased the level of Ctyc protein in vitro. LCA demonstrated a parasiticidal effect on the protoscoleces of Echinococcus granulosus in vitro. LCA may induce apoptosis of E. granulosus protoscoleces by oxidative stress and mitochondrial pathways.

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.

Assessment of the Therapeutic Efficacy of Silver Nanoparticles against Secondary Cystic Echinococcosis in BALB/c Mice

Background: Cystic echinococcosis (CE) is a highly prevalent parasitic disease resulting from the hydatid cyst of Echinococcus granulosus. It is also described as a zoonotic disease and considered a neglected tropical infection. Aim: This study assessed the antiparasitic activity of silver nanoparticles (AgNPs), against E. granulosus infection in BALB/c mice. Methods: The green synthesis of AgNPs was accomplished using Zizyphus spina-christi leaves. AgNPs were orally administered to BALB/c mice for acute short-term toxicity evaluation, in doses of 50 mg, 100 mg, 200 mg, and 300 mg/kg, and observations for toxic signs were carried out at 24, 48 h, and 14 days, continuously. Moreover, a total of 20 mice divided into two groups were intraperitoneally administered with 1500 viable protoscoleces for secondary hydatidosis infection. Results: The results showed that AgNPs did not induce any adverse effects or signs and no death, in either group of mice. The histopathological findings in the liver, kidneys, and intestine of the mice administered with AgNPs revealed mild histological effects compared with the control ones. The treated-infected mice showed a change in the appearance of the liver hydatid cysts from hyaline to milky cloudy compared with the untreated infected mice. Conclusion: Biosynthesized AgNPs showed anti-hydatic effects and are suggested as anti-echinococcal cyst treatment.

Dihydroartemisinin induces ER stress-dependent apoptosis of Echinococcus protoscoleces in vitro

In this study, we investigated the effect of dihydroartemisinin on Echinococcus protoscoleces and explored the role of endoplasmic reticulum stress in this process. Echinococcus protoscoleces were collected and cultured in RPMI 1640 medium. Changes in the expressions of glucose-regulated protein 78 (GRP-78), caspase-12, and C/EBP homologous protein (CHOP) were assessed through confocal immunofluorescence and western blot analysis. Cell viability and morphological changes were observed under a light microscope. The ultrastructure of protoscoleces was observed by scanning electron microscopy and transmission electron microscopy. Caspase-3 activity was detected using an enzyme assay kit. After dihydroartemisinin treatment, the protoscoleces showed loss of viability, and morphological changes including soma contraction, blebs formation, hooks loss, microtrichia destruction, and development of lipid droplets was observed. The levels of caspase-12 and CHOP were increased within 2 days of dihydroartemisinin treatment. However, the levels of GRP-78, caspase-12, and CHOP were decreased in 4 days. Furthermore, caspase-3 activity was increased after treatment with different concentrations of dihydroartemisinin. Dihydroartemisinin can induce apoptosis in protoscoleces via the ER stress-caspase-3 apoptotic pathway in vitro. These results indicate that dihydroartemisinin is a potentially valuable therapeutic agent against echinococcosis.

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.

Interactions between hydatid cyst and regulated cell death may provide new therapeutic opportunities

Cystic echinococcosis and alveolar echinococcosis are chronic zoonotic infections, transmitted throughout the world. Development of the cestode larval stages in the liver and lungs causes damage to intermediate hosts, including humans. Several pathways leading to the suppression of host immune response and the survival of the cysts in various hosts are known. Immune response modulation and regulated cell death (RCD) play a fundamental role in cyst formation, development and pathogenesis. RCD, referring to apoptosis, necrosis and autophagy, can be triggered either via intrinsic or extrinsic cell stimuli. In this review, we provide a general overview of current knowledge on the process of RCD during echinococcosis. The study of interactions between RCD and Echinococcus spp. metacestodes may provide in-depth understanding of echinococcosis pathogenesis and open new horizons for human intervention and treatment of the disease.

Echinococcosis: Advances in the 21st Century

Echinococcosis is a zoonosis caused by cestodes of the genus Echinococcus (family Taeniidae). This serious and near-cosmopolitan disease continues to be a significant public health issue, with western China being the area of highest endemicity for both the cystic (CE) and alveolar (AE) forms of echinococcosis. Considerable advances have been made in the 21st century on the genetics, genomics, and molecular epidemiology of the causative parasites, on diagnostic tools, and on treatment techniques and control strategies, including the development and deployment of vaccines. In terms of surgery, new procedures have superseded traditional techniques, and total cystectomy in CE, ex vivo resection with autotransplantation in AE, and percutaneous and perendoscopic procedures in both diseases have improved treatment efficacy and the quality of life of patients. In this review, we summarize recent progress on the biology, epidemiology, diagnosis, management, control, and prevention of CE and AE. Currently there is no alternative drug to albendazole to treat echinococcosis, and new compounds are required urgently. Recently acquired genomic and proteomic information can provide a platform for improving diagnosis and for finding new drug and vaccine targets, with direct impact in the future on the control of echinococcosis, which continues to be a global challenge.

Toxic effects of arsenic trioxide on Echinococcus granulosus protoscoleces through ROS production, and Ca2+-ER stress-dependent apoptosis

Cystic echinococcosis is a severe parasitic disease that commonly affects the liver and causes abscesses or rupture into the surrounding tissues, leading to multiple complications, such as shock, severe abdominal pain, and post-treatment abscess recurrence. Currently, there are no efficient measures to prevent these complications. We previously confirmed that arsenic trioxide (As2O3) exhibited in vitro cytotoxicity against Echinococcus granulosus protoscoleces. In the present study, we aimed to explore the mechanism of As2O3-induced E. granulosus protoscoleces apoptosis. After exposing E. granulosus protoscoleces to 0, 4, 6, and 8 μM As2O3, reactive oxygen species (ROS) level was detected by fluorescence microscopy; superoxide dismutase (SOD), and caspase-3 activities were measured; intracellular Ca2+ was detected by flow cytometry; GRP-78 and caspase-12 protein levels were measured by western blot analysis. Our results showed that the expression of caspase-3 was gradually increased and the expression of SOD was gradually decreased in As2O3-treated groups of protoscoleces. Simultaneously, fluorescence microscopy and flow cytometry showed that the ROS level and the intracellular Ca2+ level were increased in a time- and dose-dependent manner. Western blot analysis showed that the expressions of GRP-78 and caspase-12 were higher in As2O3-treated groups than in the control group. These results suggest that As2O3-induced apoptosis in E. granulosus protoscoleces is related to elevation of ROS level, disruption of intracellular Ca2+ homeostasis, and endoplasmic reticulum stress. These mechanisms can be targeted in the future by safer and more effective drugs to prevent recurrence of cystic echinococcosis.

Progress in the pharmacological treatment of human cystic and alveolar echinococcosis: Compounds and therapeutic targets

Human cystic and alveolar echinococcosis are helmintic zoonotic diseases caused by infections with the larval stages of the cestode parasites Echinococcus granulosus and E. multilocularis, respectively. Both diseases are progressive and chronic, and often fatal if left unattended for E. multilocularis. As a treatment approach, chemotherapy against these orphan and neglected diseases has been available for more than 40 years. However, drug options were limited to the benzimidazoles albendazole and mebendazole, the only chemical compounds currently licensed for treatment in humans. To compensate this therapeutic shortfall, new treatment alternatives are urgently needed, including the identification, development, and assessment of novel compound classes and drug targets. Here is presented a thorough overview of the range of compounds that have been tested against E. granulosus and E. multilocularis in recent years, including in vitro and in vivo data on their mode of action, dosage, administration regimen, therapeutic outcomes, and associated clinical symptoms. Drugs covered included albendazole, mebendazole, and other members of the benzimidazole family and their derivatives, including improved formulations and combined therapies with other biocidal agents. Chemically synthetized molecules previously known to be effective against other infectious and non-infectious conditions such as anti-virals, antibiotics, anti-parasites, anti-mycotics, and anti-neoplastics are addressed. In view of their increasing relevance, natural occurring compounds derived from plant and fungal extracts are also discussed. Special attention has been paid to the recent application of genomic science on drug discovery and clinical medicine, particularly through the identification of small inhibitor molecules tackling key metabolic enzymes or signalling pathways.

Human cystic and alveolar echinococcosis (CE and AE), caused by the larval stages of the helminths Echinococcus granulosus and E. multilocularis, respectively, are progressive and chronic diseases affecting more than 1 million people worldwide. Both are considered orphan and neglected diseases by the World Health Organization. As a treatment approach, chemotherapy is limited to the use of benzimidazoles, drugs that stop parasite growth but do not kill the parasite. To compensate this therapeutic shortfall, new treatment alternatives are urgently needed. Here, we present the state-of-the-art regarding the alternative compounds and new formulations of benzimidazoles assayed against these diseases until now. Some of these new and modified compounds, either alone or in combination, could represent a step forward in the treatment of CE and AE. Unfortunately, few compounds have reached clinical trials stage in humans and, when assayed, the design of these studies has not allowed evidence-based conclusions. Thus, there is still an urgent need for defining new compounds or improved formulations of those already assayed, and also for a careful design of clinical protocols that could lead to the draw of a broad international consensus on the use of a defined drug, or a combination of drugs, for the effective treatment of CE and AE.

Protoscolicidal and immunomodulatory activity of Ziziphora tenuior extract and its fractions

OBJECTIVE

To evaluate the scolicidal and immunomodulatory effect of the Ziziphora tenuior (Z. tenuior) extract and its fractions.

METHODS

Protoscolices were treated with six concentrations (3, 5, 10, 25, 50, and 100 mg/mL) of Z. tenuior extract and its fractions (ethanol, petroleum ether, ethyl acetate and chloroform) in periods of 10, 20, 30, 40, 50 and 60 min, and viability of protoscolices was evaluated using the 1.0% eosin. To examine the immunomodulatory effects of Ziziphora and its fractions on macrophage cells, the non-toxic concentration of extract and different fractions determined by MTT assay, and the Griess reaction was used to measure the level of nitrite as an indicator of nitric oxide by the macrophage cells in 10, 100 and 200 μg/mL in 24 h at 37 °C.

RESULTS

In this study, the Z. tenuior extract at 10 mg/mL concentration was able to kill all protoscolices during 20 min. By increasing the concentration to 25 mg/mL, the scolicidal time reduced to 10 min. Regarding the effect of different fractions of Z. tenuior, the ethanolic fraction showed the highest scolicidal activity. The extract demonstrated an inhibitory effect on the activity of macrophages and reduced nitric oxide production. Although the petroleum ether and ethanolic fractions of the extract reduced nitric oxide production, nevertheless, this effect was only significant at 10 and 100 μg/mL concentrations (P < 0.05).

CONCLUSION

The Z. tenuior extract and its fractions were effective against protoscolices yet the effect of total extract was considerable. Our findings indicates that the extract and its ethanolic and petroleum ether fractions could have anti-inflammatory properties.