Effect of anacardic acid against echinococcosis through inhibition of VEGF-induced angiogenesis

Current status of drug therapy for alveolar echinococcosis

Alveolar echinococcosis (AE) is a chronic zoonotic parasitic disease caused by infection with Echinococcus multilocularis. AE is associated with a high mortality rate and poses a significant threat to human health. The primary treatment for AE is surgical resection of the lesions; however, owing to its long incubation period and insidious disease progression, many patients are diagnosed only after the onset of complications such as liver cirrhosis, jaundice, and portal hypertension, which preclude curative surgical intervention. For patients who are unwilling or unable to undergo surgery, lifelong administration of anti-AE medications is necessary. Benzimidazole compounds, such as albendazole and mebendazole, are the current mainstays of treatment, offering good efficacy. Nevertheless, these medications primarily inhibit parasite proliferation rather than eradicate the infection, and their long-term use can lead to significant drug-related toxic effects. Consequently, there is an urgent need to develop new therapeutic strategies that convey better efficacy and reduce the adverse effects associated with current treatments. Recent advancements in AE therapy include novel synthetic compounds such as antiviral agents, antibiotics, antineoplastic agents, immunosuppressants, and antiangiogenic agents, as well as natural compounds derived from traditional Chinese and Tibetan medicine. These new drugs show promising clinical potential because they interfere with parasitic metabolic pathways and cellular structures. This review aims to discuss recent research on AE drug therapy, including mechanisms of action, dosing regimens, signalling pathways, and therapeutic outcomes, with a goal of providing new insights and directions for the development of anti-AE drugs and summarizing current advancements in AE pharmacotherapy.

Receptor Tyrosine Kinase Signaling Involves Echinococcus-Host Intercommunication: A Potential Therapeutic Target in Hepatic Echinococcosis

Echinococcosis, one of the most serious and life-threatening parasitic forms of zoonosis worldwide, is caused by the larvae of Echinococcus granulosus (E. granulosus) and Echinococcus multilocularis (E. multilocularis). Various drugs are being applied clinically to treat zoonosis; however, their therapeutic efficacy remains a great challenge, especially with albendazole as the preferred drug of choice. Receptor tyrosine kinase (RTK) signaling controls normal cellular proliferation, differentiation, and metabolism in humans and mammals, which are intermediate hosts of E. granulosus and E. multilocularis. Disruption of RTK signaling can cause various forms of carcinogenesis and exacerbate the progression of certain forms of parasitic disease. As a result, a significant number of studies on tyrosine kinase inhibitors (TKIs) have been conducted for the treatment of cancer and parasitic infection, with some TKIs already approved for clinical use for cancer. Notably, RTK signaling has been identified in the parasites E. granulosus and E. multilocularis; however, the mechanisms of RTK signaling response in Echinococcus-host intercommunication are not fully understood. Thus, understanding the RTK signaling response in Echinococcus-host intercommunication and the potential effect of RTK signaling is crucial for identifying new drug targets for echinococcosis. The present review illustrates that RTK signaling in the host is over-activated following infection by E. granulosus or E. multilocularis and can further facilitate the development of metacestodes in vitro. In addition, some TKIs exert strong parasitostatic effects on E. granulosus or E. multilocularis, both in vitro and/or in vivo, through downregulation of RTK signaling molecules. The summarized findings suggest that RTK signaling may be a promising drug target and that TKIs could be potential anti-Echinococcus drugs warranting further research.

Ninety-day toxicity and genotoxic effects of synthetically derived fully saturated forms of anacardic acid in mice

Organically synthesized fully saturated form of Anacardic acid (AA) has previously shown to be effective in the treatment of inflammatory autoimmune disease. In this study, organically synthesized fully saturated form of AA was orally administered to male and female Swiss albino mice for 90 consecutive days at doses of 25, 50 and 100 mg/kg BW (n = 20 per sex/group). Administration of AA was well tolerated at all dose levels. The treated animals did not show a dose-response toxicity in their hematology, liver, or metabolic profile. Minimally significant changes in serum biochemistry and hematology parameters were noted, but these were not considered to be of biological or toxicological importance and were not outside the known accepted ranges. Sporadic differences in organ weights were observed between groups, but all were minimal (<10%) and unlikely to indicate toxicity. The incidence of histopathological lesions was comparable between treated and control groups across all tested organs. Based upon these findings, the no-observed-adverse-effect level was determined to be ≥ 100 mg/kg BW, which was the highest dose tested. There were no genotoxic (mutagenic and clastogenic) effects seen in In-vivo micronucleus test, In-vitro chromosomal aberration test and Bacterial reverse mutation test. These results support, no genotoxicity and no toxicity associated with oral consumption of AA in mice as a dietary supplement for beverages and food.

Effect of sunitinib against Echinococcus multilocularis through inhibition of VEGFA-induced angiogenesis

BACKGROUND

Alveolar echinococcosis (AE) is a lethal zoonosis caused by the fox tapeworm Echinococcus multilocularis. The disease is difficult to treat, and an effective therapeutic drug is urgently needed. Echinococcus multilocularis-associated angiogenesis is required by the parasite for growth and metastasis; however, whether antiangiogenic therapy is effective for treating AE is unclear.

METHODS

The in vivo efficacy of sunitinib malate (SU11248) was evaluated in mice by secondary infection with E. multilocularis. Enzyme-linked immunosorbent assays (ELISAs) were used to evaluate treatment effects on serum IL-4 and vascular endothelial growth factor A (VEGFA) levels after SU11248 treatment. Gross morphological observations and immunohistochemical staining were used to evaluate the impact of SU11248 on angiogenesis and the expression of pro-angiogenic factors VEGFA and VEGF receptor 2 (VEGFR2) in the metacestode tissues. Furthermore, the anthelmintic effects of SU11248 were tested on E. multilocularis metacestodes in vitro. The effect of SU11248 on the expression of VEGFA, VEGFR2, and phosphorylated VEGFR2 (p-VEGFR2) in liver cells infected with protoscoleces in vitro was detected by western blotting, reverse transcription quantitative polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA). The influence of SU11248 on endothelial progenitor cell (EPC) proliferation and migration was determined using CCK8 and transwell assays.

RESULTS

In vivo, SU11248 treatment markedly reduced neovascular lesion formation and substantially inhibited E. multilocularis metacestode growth in mice. Further, it exhibited high anti-hydatid activity as efficiently as albendazole (ABZ), and the treatment resulted in reduced protoscolex development. In addition, VEGFA, VEGFR2, and p-VEGFR2 expression was significantly decreased in the metacestode tissues after SU11248 treatment. However, no effect of SU11248 on serum IL-4 levels was observed. In vitro, SU11248 exhibited some anthelmintic effects and damaged the cellular structure in the germinal layer of metacestodes at concentrations below those generally considered acceptable for treatment (0.12-0.5 μM). Western blotting, RT-qPCR, and ELISA showed that in co-cultured systems, only p-VEGFR2 levels tended to decrease with increasing SU11248 concentrations. Furthermore, SU11248 was less toxic to Reuber rat hepatoma (RH) cells and metacestodes than to EPCs, and 0.1 μM SU11248 completely inhibited EPC migration to the supernatants of liver cell and protoscolex co-cultures.

CONCLUSIONS

SU11248 is a potential candidate drug for the treatment of AE, which predominantly inhibits parasite-induced angiogenesis. Host-targeted anti-angiogenesis treatment strategies constitute a new avenue for the treatment of AE.

Female naturalists and the patterns of suppression of women scientists in history: the example of Maria Sibylla Merian and her contributions about useful plants

BACKGROUND

This work reunites many women naturalists who registered knowledge about native flora in scientific expeditions around the globe between the seventeenth and nineteenth centuries. Since male naturalists are more recognized in this period of time, we aimed to list female naturalists that published plant descriptions and observations, focusing on the work of Maria Sibylla Merian and to analyze her trajectory as an example to discuss the patterns of the suppression of women scientists. A second aim was to inventory the useful plants described in Maria Sibylla's Metamorphosis Insectorum Surinamensium and find pharmacological evidence about the traditional uses described for those plants cited as medicinal and toxic.

METHODS

A survey of female naturalists was carried out by searching information in Pubmed, Scielo, Google Scholar and Virtual Health Library. Once Maria Sibylla published her book Metamorphosis Insectorum Surinamensium by her own, without male co-authors, and also this book is one of the only to have text and illustrations altogether and there are reports indicating information on useful plants in this work, she and her book were chosen as subject of this research. All the information was tabulated by dividing the plants into food, medicinal, toxic, aromatic or other uses. Finally, with the combinations of the scientific name of medicinal and toxic plants with information about their popular uses, a search was carried out in databases in order to indicate current pharmacological studies that reported evidences about the traditional uses described.

RESULTS

We found 28 women naturalists who participated in scientific expeditions or trips, or in a curiosity cabinet, or who were collectors of Natural History between the seventeenth and nineteenth centuries. All these women illustrated botanical species and/or recorded their everyday or medicinal use or reported their observations in the form of a published work, letters or diaries. Also, the trajectory of Maria Sibylla Merian revealed that her scientific relevance has been neglected from the eighteenth century by mechanisms of suppression, most of the time by male depreciation, which can be seen as a pattern for suppression of women in science. However, Maria Sibyllas' contributions have been valued again in the twenty-first century. In Maria Sibylla's work, 54 plants were identified, 26 of them used for food, 4 of them aromatic, 8 medicinal, 4 toxic and 9 other uses.

CONCLUSION

This study evidences that there are female naturalists whose work could be an important source for ethnopharmacological studies. Researching about women scientists, talking about them and highlighting the gender bias present in the scientific academy about the way the history of science is told is essential for the construction of a more diverse and richer scientific academy. The traditional use of 7 of 8 medicinal plants and 3 of 4 toxic plants reported was correlated with pharmacological studies, highlighting the importance of this historical record and its potential to direct strategic research in traditional medicine.

Alveolar echinococcosis in immunocompromised hosts

BACKGROUND

Alveolar echinococcosis (AE) results of an infection with the larval stage of Echinococcus multilocularis. It has been increasingly described in individuals with impaired immune responsiveness.

OBJECTIVES

This narrative review aims at describing the presentation of AE according to the type of immune impairment, based on retrospective cohorts and case reports. Implications for patient management and future research are proposed accordingly.

SOURCES

Targeted search was conducted in PubMed using ((alveolar echinococcosis) OR (multilocularis)) AND ((immunosuppressive) OR (immunodeficiency) OR (AIDS) OR (solid organ transplant) OR (autoimmunity) OR (immune deficiency)). Only publications in English were considered.

CONTENT

Seventeen publications were found, including 13 reports of 55 AE in immunocompromised patients (AE/IS) and 4 retrospective studies of 755 AE immunocompetent patients and 115 AE/IS (13%). The cohorts included 9 (1%) solid organ transplantation (SOT) recipients, 2 (0.2%) HIV patients, 41 (4.7%) with chronic inflammatory/autoimmune diseases (I/AID) and 72 (8.3%) with malignancies. SOT, I/AID and malignancies, but not HIV infection, were significantly associated with AE (odds ratios of 10.8, 1.6, 5.9, and 1.3, respectively). Compared to AE immunocompetent patients, AE/IS was associated with earlier diagnosis (PNM stages I-II: 49/85 (58%) vs. 137/348 (39%), p < 0.001), high rate of atypical imaging (24/50 (48%) vs. 106/375 (28%), p < 0.01), and low sensitivity of serology (19/77 (25%) vs. 265/329 (81%), p < 0.001). Unusually extensive or disseminated infections were described in SOT and I/AID patients.

IMPLICATIONS

Patients who live in endemic areas should benefit from serology before onset of a long-term immunosuppressive therapy, even if the cost-benefit ratio has to be evaluated. Physicians should explain AE to immunocompromised patients and think about AE when finding a liver lesion. Further research should address gaps in knowledge of AE/IS. Especially, extensive and accurate records of AE cases have to be collected by multinational registries.

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.

Maca against Echinococcosis?-A Reverse Approach from Patient to In Vitro Testing

Drug-based treatment of alveolar echinococcosis (AE) with benzimidazoles is in most cases non-curative, thus has to be taken lifelong. Here, we report on a 56-year-old male AE patient who received standard benzimidazole treatment and biliary plastic stents, and additionally self-medicated himself with the Peruvian plant extract Maca (Lepidium meyenii). After 42 months, viable parasite tissue had disappeared. Based on this striking observation, the anti-echinococcal activity of Maca was investigated in vitro and in mice experimentally infected with Echinococcus multilocularis metacestodes. Albendazole (ABZ)-treated mice and mice treated with an ABZ+Maca combination exhibited a significantly reduced parasite burden compared to untreated or Maca-treated mice. As shown by a newly established UHPLC-MS/MS-based measurement of ABZ-metabolites, the presence of Maca during the treatment did not alter ABZ plasma levels. In vitro assays corroborated these findings, as exposure to Maca had no notable effect on E. multilocularis metacestodes, and in cultures of germinal layer cells, possibly unspecific, cytotoxic effects of Maca were observed. However, in the combined treatments, Maca inhibited the activity of ABZ in vitro. While Maca had no direct anti-parasitic activity, it induced in vitro proliferation of murine spleen cells, suggesting that immunomodulatory properties could have contributed to the curative effect seen in the patient.

Acyl-Acyl Carrier Protein Desaturases and Plant Biotic Interactions

Interactions between land plants and other organisms such as pathogens, pollinators, or symbionts usually involve a variety of specialized effectors participating in complex cross-talks between organisms. Fatty acids and their lipid derivatives play important roles in these biological interactions. While the transcriptional regulation of genes encoding acyl–acyl carrier protein (ACP) desaturases appears to be largely responsive to biotic stress, the different monounsaturated fatty acids produced by these enzymes were shown to take active part in plant biotic interactions and were assigned with specific functions intrinsically linked to the position of the carbon–carbon double bond within their acyl chain. For example, oleic acid, an omega-9 monounsaturated fatty acid produced by Δ⁹-stearoyl–ACP desaturases, participates in signal transduction pathways affecting plant immunity against pathogen infection. Myristoleic acid, an omega-5 monounsaturated fatty acid produced by Δ⁹-myristoyl–ACP desaturases, serves as a precursor for the biosynthesis of omega-5 anacardic acids that are active biocides against pests. Finally, different types of monounsaturated fatty acids synthesized in the labellum of orchids are used for the production of a variety of alkenes participating in the chemistry of sexual deception, hence favoring plant pollination by hymenopterans.

In vitro effects of lonidamine and 6-aminonicotinamide against Echinococcus granulosussensu stricto and Echinococcus multilocularis

Echinococcosis is a zoonotic disease caused by cestode species of the genus Echinococcus, which demonstrates considerable medical and veterinary concerns. The development of novel drugs for echinococcosis treatment is urgently needed. In this study, we demonstrated that lonidamine (LND) and 6-aminonicotinamide (6-AN) exhibited considerable in vitro effects against both larval- and adult-stage of E. granulosussensu stricto (s. s.) and E. multilocularis. The combination of LND and 6-AN exhibited a significantly higher activity than the single drug treatment. These results highlight the therapeutic potential of LND, 6-AN and the combination of LND and 6-AN for the treatment of echinococcosis.

In vitro efficacy of ampelopsin against Echinococcus granulosus and Echinococcus multilocularis

The metacestode stage of Echinococcus granulosus and Echinococcus multilocularis cause cystic echinococcosis and alveolar echinococcosis, respectively, which result in severe medical and veterinary problems. In this study, as an exploration of novel treatment agents against echinococcosis, we demonstrated that ampelopsin (AMP), which is extracted from Ampelopsis grossedentata and has been clinically used for treatments of various types of diseases including cancers for a long time, exhibited profound in vitro effect against E. granulosus protoscoleces and E. multilocularis metacestodes. Furthermore, in vitro cytotoxicity assay also demonstrated that AMP at the effective dose against E. granulosus protoscoleces and E. multilocularis metacestodes did not show significant toxicity to human hepatocytes. These results suggest that AMP has the potential as an alternative agent against echinococcosis.