RESUMO
BACKGROUND: Human toxocariasis is a neglected parasitic disease characterised by the syndromes visceral, cerebral, and ocular larva migrans. This disease is caused by the migrating larvae of Toxocara roundworms from dogs and cats, affecting 1.4 billion people globally. Via extracellular vesicles (EVs), microRNAs have been demonstrated to play roles in host-parasite interactions and proposed as circulating biomarkers for the diagnosis and follow-up of parasitic diseases. METHODS: Small RNA-seq was conducted to identify miRNAs in the infective larvae of T. canis and plasma EV-containing preparations of infected BALB/c mice. Differential expression analysis and target prediction were performed to indicate miRNAs involved in host-parasite interactions and miRNAs associated with visceral and/or cerebral larva migrans in the infected mice. Quantitative real-time polymerase chain reaction (PCR) was used to amplify circulating miRNAs from the infected mice. RESULTS: This study reports host and parasite miRNAs in the plasma of BALB/c mice with visceral and cerebral larva migrans and demonstrates the alterations of these miRNAs during the migration of larvae from the livers through the lungs and to the brains of infected mice. After filtering unspecific changes in an irrelevant control, T. canis-derived miRNAs and T. canis infection-induced differential miRNAs are predicted to modulate genes consistently involved in mitogen-activated protein kinase (MAPK) signalling and pathways regulating axon guidance and pluripotency of stem in the infected mice with visceral and cerebral larva migrans. For these plasma circulating miRNAs predicted to be involved in host-parasite crosstalk, two murine miRNAs (miR-26b-5p and miR-122-5p) are experimentally verified to be responsive to larva migrans and represent circulating biomarker candidates for visceral and cerebral toxocariasis in BALB/c mice. CONCLUSIONS: Our findings provide novel insights into the crosstalk of T. canis and the mammalian host via plasma circulating miRNAs, and prime agents and indicators for visceral and cerebral larva migrans. A deep understanding of these aspects will underpin the diagnosis and control of toxocariasis in humans and animals.
Assuntos
MicroRNA Circulante , Camundongos Endogâmicos BALB C , Toxocara canis , Toxocaríase , Animais , Toxocara canis/genética , Toxocara canis/fisiologia , Camundongos , Toxocaríase/parasitologia , Toxocaríase/sangue , MicroRNA Circulante/sangue , MicroRNA Circulante/genética , Interações Hospedeiro-Parasita , Larva Migrans Visceral/parasitologia , Larva Migrans Visceral/sangue , Feminino , Larva Migrans/parasitologia , Larva Migrans/sangue , Larva/genética , Cães , MicroRNAs/sangue , MicroRNAs/genética , Biomarcadores/sangue , Encéfalo/parasitologiaRESUMO
Toxocara cati and T. canis are parasitic nematodes found in the intestines of cats and dogs respectively, with a cosmopolitan distribution, and the potential for anthropozoonotic transmission, resulting in human toxocariasis. Spread of Toxocara spp. is primarily through the ingestion of embryonated eggs contaminating surfaces or uncooked food, or through the ingestion of a paratenic host containing a third-stage larva. The Toxocara spp. eggshell is composed of a lipid layer providing a permeability barrier, a chitinous layer providing structural strength, and thin vitelline and uterine layers, which combined create a biologically resistant structure, making the Toxocara spp. egg very hardy, and capable of surviving for years in the natural environment. The use of sodium hypochlorite, household bleach, as a disinfectant for Toxocara spp. eggs has been reported, with results varying from ineffective to limited effectiveness depending on parameters including contact time, concentration, and temperature. Desiccation or humidity levels have also been reported to have an impact on larval development and/or survival of Toxocara spp. eggs. However, to date, after a thorough search of the literature, no relevant publications have been found that evaluated the use of sodium hypochlorite and desiccation in combination. These experiments aim to assess the effects of using a combination of desiccation and 10% bleach solution (0.6% sodium hypochlorite) on fertilized or embryonated eggs of T. cati, T. canis, and T. vitulorum. Results of these experiments highlight the synergistic effects of desiccation and bleach, and demonstrate a relatively simple method for surface inactivation, resulting in a decrease in viability or destruction of T. cati, T. canis and T. vitulorum eggs. Implications for these findings may apply to larger scale elimination of ascarid eggs from both research, veterinary, and farming facilities to mitigate transmission.
Assuntos
Dessecação , Hipoclorito de Sódio , Toxocara , Animais , Hipoclorito de Sódio/farmacologia , Toxocara/efeitos dos fármacos , Toxocara/fisiologia , Óvulo/efeitos dos fármacos , Desinfetantes/farmacologia , Cães , Toxocaríase/parasitologia , Toxocaríase/prevenção & controle , Feminino , Gatos , Toxocara canis/efeitos dos fármacos , Toxocara canis/fisiologia , Larva/efeitos dos fármacosRESUMO
Neutrophils, a crucial element of the host defense system, develop extracellular traps against helminth parasites. Neutrophils accumulate around the larvae of Toxocara canis (T. canis) in the tissues of the organism. This study aimed to determine the reaction in canine neutrophils after incubation with infective stage T. canis larvae (L3) in vitro. Most L3 were still active and moved between the extracellular traps (NETs) after 60-min incubation. NETs were not disintegrated by L3 movement. The L3 was only immobilized by NETs, entrapped larvae were still motile between the traps at the 24â¯h incubation. NETs were observed not only to accumulate around the mouth, excretory pole or anus but also the entire body of live L3. The extracellular DNA amount released from the canine neutrophils after being induced with phorbol 12-myristate 13-acetate was not affected by T. canis excretory/secretory products obtained from 250 L3. To the Authors'knowledge, the extracellular trap structures was firstly observed in canine neutrophils against T. canis L3 in vitro. NETs decorated with myeloperoxidase, neutrophil elastase and histone (H3) were observed under fluorescence microscope. There were not significant differences in the amount of extracellular DNA (P > 0.05), but the morphological structure of NETs was different in the live and head-inactivated T. canis larvae.
Assuntos
Armadilhas Extracelulares , Larva , Neutrófilos , Toxocara canis , Animais , Cães , Toxocara canis/fisiologia , Neutrófilos/imunologia , Larva/fisiologia , Larva/imunologia , Doenças do Cão/parasitologia , Doenças do Cão/imunologia , Toxocaríase/parasitologia , Toxocaríase/imunologiaRESUMO
BACKGROUND: Toxocara canis (T. canis) is a helminth parasite of zoonotic and veterinary health significance that causes the disease known as Toxocariasis. This disease has been associated with conditions of poverty, especially in tropical climate zones throughout the world. Although it rarely causes important clinical manifestations, T. canis can lead to blindness, meningoencephalitis, or other nervous manifestations in humans. Moreover, some studies show its importance in the development of tumor growth, which have been associated with the parasite's ability to modulate the host's immune response. While different studies have evaluated the immune response during this disease, currently, there are no studies where the infection is analyzed from the perspective of sexual dimorphism. METHODS: To evaluate sex differences in susceptibility, we analyzed lesions and parasite loads in lung and liver at 7 days post-infection. In addition, immune cell subpopulations were analyzed in spleen, mesenteric and peripheral lymph nodes. Finally, the production of cytokines and specific antibodies were determined in the serum. Statical analyses were performed using a Two-way ANOVA and a post-hoc Bonferroni multiple comparison test. RESULTS: Female rats had a higher number of larvae in the liver, while male rats had them in the lungs. The percentages of immune cells were evaluated, and in most cases, no significant differences were observed. Regarding the cytokines production, infection can generate a decrease in Th1 such as IL-1ß in both sexes and IL-6 only in females. In the case of Th2, IL-4 increases only in infected males and IL-5 increases in males while decreasing in females due to the effect of infection. IL-10 also decreases in both sexes as a consequence of the infection, and TGF-ß only in females. Finally, the infection generates the production of antibodies against the parasite, however, their quantity is lower in females. CONCLUSIONS: This study demonstrates that T. canis infection is dimorphic and affects females more than males. This is due to a polarization of the inadequate immune response, which is reflected as a higher parasite load in this sex.
Assuntos
Toxocara canis , Toxocaríase , Humanos , Feminino , Ratos , Masculino , Animais , Toxocaríase/parasitologia , Toxocaríase/patologia , Toxocara canis/fisiologia , Caracteres Sexuais , Citocinas , ImunidadeRESUMO
Toxocara tanuki is a common large roundworm in raccoon dogs. Experimental infection studies of T. tanuki in mice were conducted to clarify the distribution and infectivity of larvae in tissue. Groups of BALB/c and C57BL/6 mice (n = 5 mice/group) were each inoculated with 1000 embryonated T. tanuki eggs and necropsied at 7, 31, 91, and 182 days post inoculation (dpi). The number of larvae in the central nervous system, heart, lungs, kidneys, spleen, gastrointestinal tract, liver, and carcass was examined. Larvae obtained from the aforementioned mice on different days of the necropsy were orally inoculated into four groups of ICR mice (n = 6 mice/group) that were then necropsied at 21 dpi. Larvae were recovered from all mice. In the BALB/c and C57BL/6 mice, most of the larvae (> 88.7%) were recovered from the liver and the remainder from other tissues. The total number of larvae recovered from C57BL/6 mice was significantly higher than that from BALB/c mice, but no difference in the relative larval distribution within the viscera between the two mouse strains was observed. The mean recovery percentage of larvae from ICR mice infected with 182-day-old tissue larvae was 3.3%. Our findings showed that T. tanuki larvae migrated predominantly to the liver of mice and that the larvae maintained their infectivity for at least half a year.
Assuntos
Toxocara canis , Toxocaríase , Animais , Camundongos , Toxocara , Larva/fisiologia , Camundongos Endogâmicos ICR , Camundongos Endogâmicos C57BL , Pulmão , Fígado , Toxocara canis/fisiologiaRESUMO
A global lipidomic analysis using liquid chromatography-tandem mass spectrometry was performed on the liver of beagle dogs infected with Toxocara canis to profile hepatic lipid species at 12 h post-infection (hpi), 24 hpi, and 36 days post-infection (dpi). This analysis identified six categories and 42 subclasses of lipids, including 173, 64, and 116 differentially abundant lipid species at 12 hpi, 24 hpi, and 36 dpi, respectively. Many of the identified lysophospholipids, such as lysophosphatidylglycerol, lysophosphatidylserine, and lysophosphatidylcholine, may contribute to the migration and development of T. canis during the early infection stage. Pathway analysis revealed significant alterations of several immune-inflammatory pathways, such as the B-cell receptor signaling pathway, the NF-kappa B signaling pathway, and the C-type lectin receptor signaling pathway at 12 and 24 hpi. These findings demonstrate the value of lipidomic profiling in revealing the extent of changes in the composition and abundance of hepatic lipidome caused by T. canis infection and their relevance to the pathophysiology of toxocariasis in beagle dogs.
Assuntos
Doenças do Cão , Toxocara canis , Toxocaríase , Animais , Cães , Lectinas Tipo C , Lipidômica , Fígado , Lisofosfatidilcolinas , NF-kappa B , Receptores de Antígenos de Linfócitos B , Toxocara canis/fisiologiaRESUMO
Human toxocariasis consists of chronic tissue parasitosis that is difficult to treat and control. This study aimed to evaluate the action of the probiotic Lactobacillus acidophilus ATCC 4356 on larvae of Toxocara canis and the effect of IFN-γ cytokine on parasite-host in vivo (1.109 CFU) and in vitro (1.106, 1.107, 1.108, 1.109 CFU) interactions. Four groups of six BALB/c mice were formed: G1 - L. acidophilus supplementation and T. canis infection; G2 - T. canis infection; G3 - L. acidophilus supplementation; and G4 - PBS administration. Mice were intragastrically suplemented with probiotics for 15 days before inoculation and 48 h after inoculation with 100 T. canis eggs. The inoculation of T. canis was also perfomed intragastrically. The recovery of larvae took place through digestion of liver and lung tissues; the evaluation of IFN-γ gene transcription in leukocytes was performed by qPCR. The in vitro test consisted of incubating the probiotic with T. canis larvae. The supplementation of probiotics produced a reduction of 57.7% (p = 0.025) in the intensity of infection of T. canis larvae in mice, whereas in the in vitro test, there was no larvicidal effect. In addition, a decrease in the IFN-γ gene transcription was observed in both, T. canis-infected and uninfected mice, regardless of whether or not they received supplementation. The probiotic L. acidophilus ATCC 4356 reduced T. canis infection intensity in mice, however, the probiotic did not have a direct effect on larvae, demonstrating the need of interaction with the host for the beneficial effect of the probiotic to occur. Yet, the proinflammatory cytokine IFN-γ did not apparently contributed to the observed beneficial effect of probiotics.
Assuntos
Lactobacillus acidophilus/efeitos dos fármacos , Probióticos/administração & dosagem , Toxocara canis/efeitos dos fármacos , Toxocaríase/tratamento farmacológico , Toxocaríase/prevenção & controle , Animais , Lactobacillus , Larva/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Probióticos/farmacologia , Toxocara canis/microbiologia , Toxocara canis/fisiologia , Toxocaríase/parasitologiaRESUMO
Hepatic toxocarosis is caused by the dog´s roundworm, Toxocara canis. Responsible for an eosinophilic inflammatory syndrome causing liver damage that can be detected on ultrasound, computed tomography and sometimes magnetic resonance imaging. We report the case of a nine-year-old child, living in countryside, with a notion of cohabitation with canids. He presented a digestive symptomatology revealed by abdominal pain, with a hemeosinophilia in the hemogram. The etiological assessment of hyper eosinophilia objectified a positive Toxocara canisserology. The imaging assessment in search of digestive visceral lesions, found multiple heterogeneous hypoechogenic areas, poorly defined, scattered in the liver. On the abdominal CT scan, its areas appear of unenhanced density and low density and better visible after injection of contrast product. This observation reveals that imagery, although not very specific, helps in the assessment of liver damage from digestive toxocarosis.
Assuntos
Larva Migrans Visceral/diagnóstico , Toxocara canis/fisiologia , Albendazol/uso terapêutico , Animais , Criança , Humanos , Larva Migrans Visceral/tratamento farmacológico , Hepatopatias Parasitárias/diagnóstico , Hepatopatias Parasitárias/tratamento farmacológico , Imageamento por Ressonância Magnética , Masculino , Tomografia Computadorizada por Raios X , UltrassonografiaRESUMO
This review covers the systematics and nomenclature of the Ascaridoid genus toxocara, and more specifically the species Toxocara canis and Toxocara cati. Also discussed is the discovery of the persistence of these larvae in the tissues of paratenic hosts, and the role that other species of this genus might or could play in other such hosts; including those where the life cycle has been described, i.e., Toxocara vitulorum, Toxocara pteropodis, Toxocara mackerrasae, and Toxocara tanuki. Also examined is the work that led to the realization that the larval stage leaving the egg actually being a third rather than a second stage larva. Also discussed on the work showing that the larvae can persist in paratenic host with remarkable longevity without undergoing any morphological change for years and that these larvae can be transmitted from one paratenic host to another by ingestion. People are usually infected by the ingestion of eggs containing third-stage larvae, but infections also occur on occasions from the ingestion of uncooked paratenic hosts.
Assuntos
Larva Migrans/parasitologia , Toxocara/fisiologia , Toxocaríase/parasitologia , Animais , História do Século XX , Humanos , Larva , Larva Migrans/história , Toxocara/classificação , Toxocara canis/fisiologia , Toxocaríase/históriaRESUMO
This review describes the morphology and ultrastructure of the third-stage larva of Toxocara canis, the larval stage that hatches from the egg and persists in the tissues of various paratenic hosts including infected humans. This larva remains unchanged as it passes from host to host and lives for extended periods in this same body form until it makes its way to the gastro-intestinal tract of its final host. There has been less work on the anatomy and ultrastructure of the larva of Toxocara cati, but overall, it appears very similar to that of T. canis with the only apparent difference being that the larva is a few microns thinner in diameter. The paper describes the anatomy and ultrastructure of the larva and the various major structures of the various body systems including the cuticle, hypodermis, the nervous tissue, oesophagus and the lumen-free intestine, and the large excretory gland cell that fills much of the pseudocoel and which appears to be the source of the components that are recognized immunologically by the infected host. It is suggested that further detailed studies on the larva could provide significant information that would allow a greater understanding of how the larva persists within these hosts and may provide information that would make the larva an excellent link to work on nematode anatomy that would link the work being done with this model system to that of Caenorhabditis elegans and the large amount of historical work already performed on adult ascaridoid nematodes.
Assuntos
Toxocara canis/anatomia & histologia , Toxocara/anatomia & histologia , Animais , Humanos , Larva , Toxocara/fisiologia , Toxocara canis/fisiologiaRESUMO
Toxocara spp. (T. canis and T. cati) are the dominant ascarids of domestic dogs and cats, respectively, in populated regions of southern Canada, where they pose animal and public health concerns. A review of the published literature indicated that prevalence of both parasites is declining in more recent studies (post 2000), likely due to changes in animal husbandry as well as use of anthelmintics. Geographically, prevalence was higher in the east (Atlantic), and in more southerly locations, possibly due to more favourable climate conditions for egg survival and development. At northern latitudes and in wild felids and canids in general, the non-zoonotic ascarid Toxascaris leonina appears to outcompete Toxocara spp.; however, T. leonina is rare in domestic cats in Canada. Prevalence of Toxocara spp. was higher in cats than dogs, shelter/rural/remote/feral/stray vs owned animals, and young vs adult animals, as has been observed in many other studies and regions of the world. While the regional prevalences in this review should be interpreted carefully in light of variation in diagnostic methods and study populations, they generally follow the same trends observed in a recent national study of shelter animals. This review is a timely summary of the state of the published knowledge on prevalence of Toxocara spp. in Canada, and highlights knowledge gaps to be addressed, including the northern distributional limits of these species in Canada, the potential for transmission to and from wildlife hosts, and the public health significance of the parasite in the mainstream Canadian population.
Assuntos
Doenças do Gato/epidemiologia , Doenças do Cão/epidemiologia , Toxocara , Toxocaríase/epidemiologia , Animais , Canadá/epidemiologia , Doenças do Gato/parasitologia , Gatos , Doenças do Cão/parasitologia , Cães , Prevalência , Toxocara/fisiologia , Toxocara canis/fisiologia , Toxocaríase/parasitologiaRESUMO
Helminthic infection and the parallel host immune reactions are the results of a protracted dynamic co-interaction between the host and worms. An assessment of the effect of Toxocara canis infection on arthritis in rats stimulated by Freund's complete adjuvant (FCA) was the main purpose of the investigation. An arthritis model was established by the administration of 0.1 mL FCA in the palmar surface. Cytokine assessment, evaluating oedema and the use of a rheumatoid arthritis (RA) score provided evidence of the protective effects of T canis against adjuvant-induced arthritis (AIA). The cytokines TGF-ß, IFN-É£, IL-10 and IL-17 were measured to assess the anti-inflammatory effect of T canis infection. Besides, arthritis swelling findings were evaluated in rat paws. The data showed that T canis infection significantly modulated the immune response by alleviating inflammatory cytokines and increasing TGF-ß as an anti-inflammatory cytokine. Evaluations of arthritis swelling showed low severity and faster recuperation. These findings suggest that the products derived from T canis eggs might be a potential therapeutic candidate to treat autoimmune diseases like the arthritis.
Assuntos
Anti-Inflamatórios/farmacologia , Artrite Experimental/prevenção & controle , Adjuvante de Freund/efeitos adversos , Inflamação/prevenção & controle , Toxocara canis/fisiologia , Fator de Crescimento Transformador beta/sangue , Animais , Artrite Experimental/induzido quimicamente , Citocinas/sangue , Feminino , Injeções Intradérmicas , Articulações/patologia , Larva , Masculino , Distribuição Aleatória , Ratos , Ratos WistarRESUMO
BACKGROUND: Ascarid infections are among the most prevalent intestinal parasitic infections occurring in dogs around the world, with Toxocara canis and Toxascaris leonina commonly observed. Toxocara canis can cause considerable disease in dogs and humans, and year-round prophylactic treatment and control in dogs is recommended. Elimination of immature stages of these parasites before egg-laying will reduce environmental contamination and the risk of infection for both dogs and humans. Studies were conducted to evaluate the efficacy of a novel, oral chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against induced immature adult (L5) and adult T. canis, and adult T. leonina infections in dogs. METHODS: Six negative-controlled, masked, randomized laboratory studies were conducted. Two studies each evaluated efficacy against immature adult (L5) T. canis, adult T. canis, and adult T. leonina. Sixteen to 40 dogs were included in each study. Dogs experimentally infected with the target parasite were dosed once on Day 0 with either placebo tablets or Simparica Trio™ tablets to provide minimum dosages of 1.2 mg/kg sarolaner, 24 µg/kg moxidectin and 5.0 mg/kg pyrantel (as pamoate salt). Efficacy was based on the number of worms recovered at necropsy 7-10 days after treatment compared to placebo control. RESULTS: Based on geometric mean worm counts, efficacy of the sarolaner + moxidectin + pyrantel combination was ≥ 95.2% against immature adult T. canis, ≥ 97.3% against adult T. canis, and ≥ 89.7% against adult T. leonina. There were no treatment-related adverse events in any study. CONCLUSIONS: These studies confirm the efficacy of a single dose of a new oral chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against immature adult and adult T. canis, and adult T. leonina infections in dogs.
Assuntos
Antinematódeos/administração & dosagem , Infecções por Ascaridida/veterinária , Doenças do Cão/tratamento farmacológico , Enteropatias Parasitárias/veterinária , Administração Oral , Animais , Infecções por Ascaridida/tratamento farmacológico , Azetidinas/administração & dosagem , Cães , Combinação de Medicamentos , Feminino , Enteropatias Parasitárias/tratamento farmacológico , Macrolídeos/administração & dosagem , Masculino , Contagem de Ovos de Parasitas , Pirantel/administração & dosagem , Compostos de Espiro/administração & dosagem , Comprimidos , Toxascaris/efeitos dos fármacos , Toxascaris/fisiologia , Toxocara canis/efeitos dos fármacos , Toxocara canis/fisiologia , Resultado do TratamentoRESUMO
Probiotics have shown promising results as a potential method to control toxocariasis in mice inoculated with embryonated eggs of Toxocara canis. This study aimed to evaluate the protective effect of Saccharomyces boulardii in mice fed in natura chicken livers infected with T. canis. Twenty 15-day-old male Sussex chickens were inoculated with 300 T. canis embryonated eggs via intragastric catheter (GI). After 72 h of infection, each liver was collected and individually offered to a group of 20 mice. Mice that received supplemented ration with S. boulardii (1.107 colony forming units) and consumed in natura chicken liver showed reduction in infection intensity of 67.1%. This study demonstrated that administration of S. boulardii has potential as a probiotic to assist in controlling visceral toxocariasis caused by the consumption of viscera from paratenic hosts containing infective parasite larvae.
Assuntos
Probióticos , Saccharomyces boulardii/fisiologia , Toxocaríase/microbiologia , Toxocaríase/parasitologia , Animais , Galinhas/microbiologia , Galinhas/parasitologia , Larva/efeitos dos fármacos , Fígado/parasitologia , Masculino , Camundongos , Toxocara canis/fisiologiaRESUMO
BACKGROUND: Somatic migration of Toxocara canis- and T. cati-larvae in humans may cause neurotoxocarosis (NT) when larvae accumulate and persist in the central nervous system (CNS). Host- or parasite-induced immunoregulatory processes contribute to the pathogenesis; however, detailed data on involvement of bioactive lipid mediators, e.g. oxylipins or eico-/docosanoids, which are involved in the complex molecular signalling network during infection and inflammation, are lacking. METHODOLOGY/PRINCIPAL FINDINGS: To elucidate if T. canis- and T. cati-induced NT affects the homeostasis of oxylipins during the course of infection, a comprehensive lipidomic profiling in brains (cerebra and cerebella) of experimentally infected C57BL/6J mice was conducted at six different time points post infection (pi) by liquid-chromatography coupled to electrospray tandem mass spectrometry (LC-ESI-MS/MS). Only minor changes were detected regarding pro-inflammatory prostaglandins (cyclooxygenase pathway). In contrast, a significant increase of metabolites resulting from lipoxygenase pathways was observed for both infection groups and brain regions, implicating a predominantly anti-inflammatory driven immune response. This observation was supported by a significantly increased 13-hydroxyoctadecadienoic acid (HODE)/9-HODE ratio during the subacute phase of infection, indicating an anti-inflammatory response to neuroinfection. Except for the specialised pro-resolving mediator (SPM) neuroprotectin D1 (NPD1), which was detected in mice infected with both pathogens during the subacute phase of infection, no other SPMs were detected. CONCLUSIONS/SIGNIFICANCE: The obtained results demonstrate the influence of Toxocara spp. on oxylipins as part of the immune response of the paratenic hosts. Furthermore, this study shows differences in the alteration of the oxylipin composition between T. canis- and T. cati-brain infection. Results contribute to a further understanding of the largely unknown pathogenesis and mechanisms of host-parasite interactions during NT.
Assuntos
Encefalopatias/parasitologia , Oxilipinas/química , Toxocara canis/fisiologia , Toxocaríase/imunologia , Toxocaríase/parasitologia , Animais , Encéfalo/imunologia , Química Encefálica , Encefalopatias/imunologia , Ácidos Docosa-Hexaenoicos/imunologia , Feminino , Humanos , Mediadores da Inflamação/química , Mediadores da Inflamação/imunologia , Larva/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Oxilipinas/imunologiaRESUMO
Infective larvae of Toxocara canis and T. cati, the common roundworms of dogs and cats, may invade the central nervous system of paratenic hosts, including humans, causing neurotoxocarosis (NT). Previous studies on NT in the model organism "mouse" have indicated distinct differences between T. canis and T. cati regarding larval migration patterns as well as the severity of clinical symptoms and behavioural alterations. The objective of the present study was to provide an extensive characterization of the underlying histopathological alterations, comparing T. canis- and T. cati-induced changes in different brain areas over the course of murine infection. Four histological sections of five brains each of T. canis- and T. cati-infected as well as uninfected C57Bl/6 mice were investigated 7, 14, 28, 42, 70 and 98 days post infection (dpi), while brains of T. cati-infected and control mice were also available 120 and 150 dpi. In addition to haematoxylin-eosin and luxol fast blue-cresyl violet staining, immunohistochemistry was employed to study microglia/macrophage cell morphology and to detect accumulation of ß-amyloid precursor protein (ß-APP) as an indicator of axonal damage. Haemorrhages, eosinophilic vasculitis and activated microglia/macrophages were detected in both infection groups starting 7 dpi, followed by eosinophilic meningitis in cerebra as from 14 dpi. Overall, little differences in the proportion of animals affected by these alterations were found between the two infection groups. In contrast, the proportion of animals displaying ß-APP accumulation was significantly higher in the T. canis than T. cati group as from 28 dpi regarding the cerebrum as well as at 98 dpi regarding the cerebellum. In T. canis-infected mice, myelinophagic microglia/macrophages ("gitter cells") appeared as from 14 dpi, whereas these were first observed at 70 dpi in T. cati-infected animals. The proportion of animals displaying demyelination and/or gitter cells in the cerebrum was significantly higher in the T. canis than T. cati group as from 28 dpi, and at 28 and 42 dpi regarding the cerebellum. Earlier and more severe neurodegeneration during T. canis- than T. cati-induced NT, especially in the cerebrum, may explain the differences in behavioural alterations observed in previous studies. In addition to differences in larval migration preferences, immunological processes may contribute to these patterns, which warrant further investigation.
Assuntos
Toxocara canis/fisiologia , Toxocaríase/parasitologia , Toxoplasmose Cerebral/parasitologia , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/parasitologia , Encéfalo/patologia , Modelos Animais de Doenças , Feminino , Humanos , Larva/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Toxocara canis/imunologia , Toxocaríase/metabolismo , Toxocaríase/patologia , Toxoplasmose Cerebral/metabolismo , Toxoplasmose Cerebral/patologiaRESUMO
The in vitro effect of progesterone in T. canis larvae on their enlargement and motility were evaluated, together to the possible presence of progesterone receptors (PRs). T. canis larvae were cultured in RPMI-1640 with different concentrations of progesterone (0, 20, 40, 80, 400 and 800 ng/mL). Enlargement and increases in motility were dependent on the concentration only from 0 to 80 ng/mL (p < 0.05). The mean percentage of PR + cells in newly obtained larvae as measured by flow cytometry was 8.16 ± 0.4. The number of PR + cells increased depending on concentration from 0 to 80 ng/mL (p < 0.001). Cells obtained from larvae stimulated at any of the studied hormone concentrations showed greater mean fluorescence intensity when compared to non-stimulated cells. Additionally, the expression and location of PR + cells were determined in the larvae. The sequence of an amplicon (420-bp) obtained by PCR from T. canis larvae showed 100% homology with a gene fragment that codes for the PR of the dog. PR + cells were immunolocated using confocal microscopy in the intestinal region of the larvae that had been recently obtained. The results of this study show that T. canis larvae can recognize and respond to the presence of progesterone through a molecule possibly able to bind it. Since we previously observed a similar response to prolactin, we suggest that both hormones could participate sequentially in the reactivation of T. canis larvae in pregnant bitches.
Assuntos
Progesterona/farmacologia , Progestinas/farmacologia , Receptores de Progesterona/efeitos dos fármacos , Toxocara canis/efeitos dos fármacos , Animais , Sequência de Bases , DNA de Helmintos/química , DNA de Helmintos/isolamento & purificação , Cães , Feminino , Citometria de Fluxo , Intestinos/parasitologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/fisiologia , Camundongos , Microscopia Confocal , Movimento/efeitos dos fármacos , Reação em Cadeia da Polimerase , Receptores de Progesterona/análise , Receptores de Progesterona/genética , Receptores de Progesterona/metabolismo , Toxocara canis/crescimento & desenvolvimento , Toxocara canis/fisiologiaRESUMO
BACKGROUND: Toxocara canis is quite closely related to Ascaris suum but its biology is more complex, involving a phase of arrested development (diapause or hypobiosis) in tissues as well as transplacental and transmammary transmission routes. In the present study, we explored and compared dauer-like signalling pathways of T. canis and A. suum to infer which components in these pathways might associate with, or regulate, this added complexity in T. canis. METHODS: Guided by information for Caenorhabditis elegans, we bioinformatically inferred and compared components of dauer-like signalling pathways in T. canis and A. suum using genomic and transcriptomic data sets. In these two ascaridoids, we also explored endogenous dafachronic acids (DAs), which are known to be critical in regulating larval developmental processes in C. elegans and other nematodes, by liquid chromatography-mass spectrometry (LC-MS). RESULTS: Orthologues of C. elegans dauer signalling genes were identified in T. canis (n = 55) and A. suum (n = 51), inferring the presence of a dauer-like signalling pathway in both species. Comparisons showed clear differences between C. elegans and these ascaridoids as well as between T. canis and A. suum, particularly in the transforming growth factor-ß (TGF-ß) and insulin-like signalling pathways. Specifically, in both A. suum and T. canis, there was a paucity of genes encoding SMAD transcription factor-related protein (daf-3, daf-5, daf-8 and daf-14) and insulin/insulin-like peptide (daf-28, ins-4, ins-6 and ins-7) homologues, suggesting an evolution and adaptation of the signalling pathway in these parasites. In T. canis, there were more orthologues coding for homologues of antagonist insulin-like peptides (Tc-ins-1 and Tc-ins-18), an insulin receptor substrate (Tc-ist-1) and a serine/threonine kinase (Tc-akt-1) than in A. suum, suggesting potentiated functional roles for these molecules in regulating larval diapause and reactivation. A relatively conserved machinery was proposed for DA synthesis in the two ascaridoids, and endogenous Δ4- and Δ7-DAs were detected in them by LC-MS analysis. Differential transcription analysis between T. canis and A. suum suggests that ins-17 and ins-18 homologues are specifically involved in regulating development and migration in T. canis larvae in host tissues. CONCLUSION: The findings of this study provide a basis for functional explorations of insulin-like peptides, signalling hormones (i.e. DAs) and related nuclear receptors, proposed to link to development and/or parasite-host interactions in T. canis. Elucidating the functional roles of these molecules might contribute to the discovery of novel anthelmintic targets in ascaridoids.
Assuntos
Biologia Computacional , Mamíferos/parasitologia , Transdução de Sinais/fisiologia , Toxocara canis/fisiologia , Sequência de Aminoácidos , Animais , Ascaris suum/fisiologia , Caenorhabditis elegans , Sequência Conservada , Regulação da Expressão Gênica , Proteínas de Helminto/genética , Proteínas de Helminto/metabolismo , Interações Hospedeiro-Parasita , Modelos Biológicos , Toxocara canis/genéticaAssuntos
Larva Migrans Visceral/complicações , Mielite/diagnóstico , Mielite/etiologia , Doenças da Coluna Vertebral/complicações , Adulto , Animais , Humanos , Masculino , Mielite/parasitologia , Doenças da Coluna Vertebral/parasitologia , Toxocara canis/isolamento & purificação , Toxocara canis/fisiologiaRESUMO
Toxocariasis is a zoonotic disease produced by ingestion of larval Toxocara spp. eggs. Prolactin (PRL) has been considered to have an important role in Toxocara canis infection. Recent evidence has found that PRL directly can increase parasite growth and differentiation of T. canis The present study, evaluated the effect of high PRL levels on the immune system's response and parasites clearance in chronic infection. Our results showed that hyperprolactinemia did not affect the number of larvae recovered from several tissues in rats. Parasite-specific antibody production, showed no difference between the groups. Lung tissue presented eosinophilic granulomas typical of a chronic infection in all the experimental groups. Flow cytometry analysis was made in order to determine changes in the percentage of innate and adaptive immune cell subpopulations in the spleen, peripheric (PLN) and mesenteric (MLN) lymphatic nodes. The results showed a differential effect of PRL and infection on different immune compartments in the percent of total T cells, T helper cells, T cytotoxic cells, B cells, NK cells, and Tγδ cells. To our knowledge, for the first time it is demonstrated that PRL can have an immunomodulatory role during T. canis chronic infection in the murine host.