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Bernardová N, Novák J, Horák P, Fan CK, Kolářová L. Neurobehavioral Disorders and Pathological Changes in the Brain of Mice Are Caused by Chronic Toxocara canis Larval Invasion with Low to Moderate Inoculum. Acta Parasitol 2024:10.1007/s11686-024-00869-0. [PMID: 39240446 DOI: 10.1007/s11686-024-00869-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Accepted: 07/23/2024] [Indexed: 09/07/2024]
Abstract
Toxocara canis larvae are one of the most overlooked agents of nervous system infection in paratenic hosts. Previous studies in mouse models have shown that infection with various (mainly high) numbers of larvae leads to neurobehavioral disturbances and pathological changes. Our study investigated whether the infection with low and moderate numbers of larvae could affect the physical condition, motor skills, and pathogenesis in the brains of experimentally infected mice.Two groups of BALB/c mice were orally infected with 10 and 100 T. canis larvae per animal and examined regularly until the 97th week after infection. General appearance, specific antibody responses, and motor/balance skills were assessed. The number and viability of larvae in the liver, spleen, lungs, and brain were assessed by quantitative compressed biopsy technique, while the pathological changes of the brain infection were studied histologically.As a result, changes were observed in overall appearance, activity, as well as motor and balance ability. The infections were associated with an increased IgG antibody response to the specific anti-T. canis excretory/secretory antigen and tissue damage in the brain characterized by necrosis, cell infiltrations, including foamy cells, and hemorrhages.The study demonstrated the effects of low and moderate T. canis infection in a paratenic host during the chronic phase of infection, which lasted up to 97 weeks for the first time.
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Affiliation(s)
- Nicol Bernardová
- Institute of Immunology and Microbiology, 1st Faculty of Medicine, Charles University and General University Hospital, Prague, Czechia.
| | - Jan Novák
- Institute of Immunology and Microbiology, 1st Faculty of Medicine, Charles University and General University Hospital, Prague, Czechia
| | - Petr Horák
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czechia
| | - Chia-Kwung Fan
- Department of Molecular Parasitology and Tropical Diseases, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Libuše Kolářová
- Institute of Immunology and Microbiology, 1st Faculty of Medicine, Charles University and General University Hospital, Prague, Czechia
- National Reference Laboratory for Tissue Helminthosis, General University Hospital, Prague, Czechia
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Khatir AA, Mousavi F, Sepidarkish M, Arshadi M, Arjmandi D, Aldaghi M, Rostami A. Association between Alzheimer's disease and Toxocara infection/exposure: a case-control study. Trans R Soc Trop Med Hyg 2024:trae039. [PMID: 38899453 DOI: 10.1093/trstmh/trae039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 05/08/2024] [Accepted: 06/03/2024] [Indexed: 06/21/2024] Open
Abstract
BACKGROUND Infections may contribute to Alzheimer's disease (AD) risk. Limited evidence suggests Toxocara spp. infection/exposure could influence AD development. METHODS We investigated Toxocara seropositivity and AD in Iranian adults using a matched case-control study. Our sample included 90 AD cases and 91 healthy older adults. Anti-Toxocara immunoglobulin G (IgG) antibodies were assessed via enzyme-linked immunosorbent assay. We computed the odds ratios (ORs) and 95% confidence intervals (CIs) through univariable and multivariable analyses, adjusting for potential confounders. RESULTS There were 33/90 (36.67% [95% CI 26.75 to 47.48]) anti-Toxocara IgG seropositive individuals identified among the AD cases and 21/91 (23.07% [95% CI 14.89 to 33.09]) among the healthy controls. In univariable analysis, a significant association was identified between anti-Toxocara IgG seropositivity and AD (OR 1.93 [95% CI 1.01 to 3.69], p<0.001). Moreover, the association remained significant (OR 2.18 [95% CI 1.05 to 4.49], p<0.001) in multivariable analysis after adjustment for covariates. There was no association between anti-Toxocara IgG seropositivity and the severity of AD (OR 0.75 [95% CI 0.21 to 2.61], p=0.47). CONCLUSIONS Our findings indicated that Toxocara exposure/infection could be a potential risk factor for development of AD. To better understand a real causality between Toxocara exposure/infection and AD and related dementias, follow-up designed and adequately powered studies are needed.
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Affiliation(s)
- Ali Alizadeh Khatir
- Mobility Impairment Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Fariborz Mousavi
- Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Mahdi Sepidarkish
- Department of Biostatistics and Epidemiology, School of Public Health, Babol University of Medical Sciences, Babol, Iran
| | - Mahdi Arshadi
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Delaram Arjmandi
- Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Maryam Aldaghi
- Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Ali Rostami
- Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
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Elgendy DI, Elmahy RA, Amer AIM, Ibrahim HA, Eltantawy AF, Mansour FR, Salama AM. Efficacy of artemether against toxocariasis in mice: parasitological and immunopathological changes in brain, liver, and lung. Pathog Glob Health 2024; 118:47-64. [PMID: 37978995 PMCID: PMC10769145 DOI: 10.1080/20477724.2023.2285182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023] Open
Abstract
Toxocariasis is a zoonosis that represents a serious threat to public health particularly in tropical and subtropical areas. Currently, albendazole, the most effective drug for treating visceral toxocariasis, shows moderate efficacy against the larvae in tissues and has some adverse effects. Artemether is an antiparasitic drug mainly used in the treatment of malaria and showed effectiveness against numerous helminthic infections. Besides, it possesses potent anti-inflammatory, antiapoptotic, antifibrotic, and neuroprotective properties. Thus, the study's aim was to investigate artemether's effects in comparison with albendazole on the therapeutic outcome of experimental toxocariasis. For this aim, 140 laboratory-bred mice were divided into four main groups: uninfected control, treatment control, albendazole-treated, and artemether-treated groups. The treatment regimens were started at the 15th dpi (early treatment), and at the 35th dpi (late treatment). The effectiveness of treatment was determined by brain larval count, histopathological, immunohistochemical, and biochemical examination. Artemether showed more effectiveness than albendazole in reducing brain larval counts, markers of brain injury including NF-κB, GFAP, and caspase-3, the diameter and number of hepatic granulomas, hepatic oxidative stress, hepatic IL-6, and TG2 mRNA, and pulmonary inflammation and fibrosis. The efficacy of artemether was the same when administered early or late in the infection. Finally, our findings illustrated that artemether might be a promising therapy for T. canis infection and it could be a good substitution for albendazole in toxocariasis treatment.
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Affiliation(s)
- Dina I. Elgendy
- Medical Parasitology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Rasha A. Elmahy
- Zoology Department, Faculty of Science, Tanta University, Tanta, Egypt
| | | | - Hoda A. Ibrahim
- Medical Biochemistry Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Asmaa Fawzy Eltantawy
- Medical Pharmacology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Fotouh Rashed Mansour
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Tanta University, Tanta, Egypt
| | - Amina M. Salama
- Medical Parasitology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
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Salama AM, Elmahy RA, Ibrahim HA, Amer AIM, Eltantawy AF, Elgendy DI. Effects of metformin on parasitological, pathological changes in the brain and liver and immunological aspects during visceral toxocariasis in mice. Parasitol Res 2023; 122:3213-3231. [PMID: 37874393 PMCID: PMC10667394 DOI: 10.1007/s00436-023-08011-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 10/12/2023] [Indexed: 10/25/2023]
Abstract
There are currently insufficient anthelmintic medications available for the treatment of toxocariasis. For instance, Albendazole (ABZ) is the preferred medication, but its effectiveness against tissue-dwelling parasites is limited. In addition, Metformin (MTF) is a widely used oral antidiabetic medication that is considered to be safe for treatment. This study aimed to investigate any potential effects of MTF, alone or in combination with ABZ, on mice infections caused by Toxocara canis (T. canis). The efficacy of the treatment was assessed in the acute and chronic phases of the infection by larval recovery and histopathological, immunohistochemical, and biochemical studies. The results showed that combined therapy significantly reduced larval counts in the liver, brain, and muscles and ameliorated hepatic and brain pathology. It reduced oxidative stress and TGF-β mRNA expression and increased FGF21 levels in the liver. It decreased TNF-α levels and MMP-9 expression in the brain. In addition, it increased serum levels of IL-12 and IFN-γ and decreased serum levels of IL-4 and IL-10. In the acute and chronic phases of the infection, the combined treatment was more effective than ABZ alone. In conclusion, this study highlights the potential role of MTF as an adjuvant in the treatment of experimental T. canis infection when administered with ABZ.
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Affiliation(s)
- Amina M Salama
- Medical Parasitology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Rasha A Elmahy
- Zoology Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Hoda A Ibrahim
- Medical Biochemistry Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | | | - Asmaa Fawzy Eltantawy
- Medical Pharmacology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Dina I Elgendy
- Medical Parasitology Department, Faculty of Medicine, Tanta University, Tanta, Egypt.
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Song G, Yang C, Qu Z, Lin X, Liu M, Wang Y. Association between seropositivity for toxocariasis and cognitive functioning in older adults: an analysis of cross-sectional data from the US National Health and Nutrition Examination Survey (NHANES), 2011-2014. BMJ Open 2023; 13:e068974. [PMID: 36858467 PMCID: PMC9980365 DOI: 10.1136/bmjopen-2022-068974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
OBJECTIVES This study sought to examine the relationship between seropositivity for toxocariasis and cognitive functioning in a nationally representative sample of US older adults. DESIGN A cross-sectional study. SETTING National Health and Nutrition Examination Survey (NHANES) data collection took place in the US at participants' homes and mobile examination centres with specialised equipment. PARTICIPANTS The study population consisted of 3188 community-dwelling US older adults aged 60 and above from the NHANES 2011 to 2014. OUTCOME MEASURES IgG antibody against Toxocara spp was tested by a Luminex assay using recombinant rTc-CTL-1 antigen. A value >23.1 mean fluorescence intensity (MFI) indicated positive for toxocariasis and a value ≤23.1 MFI as negative for toxocariasis. The Consortium to Establish a Registry for Alzheimer's Disease Word Learning subtest immediate and delayed memory, the Animal Fluency test and the Digit Symbol Substitution Test (DSST) were used to assess cognitive functioning. Cognitive test-specific and global cognitive z scores were computed using sample means and SD. RESULTS The study population consisted of 3188 participants who represented a total of 111 896 309 civilian citizens in the USA. The mean age of the participants was 69.6 years (standard deviation 6.8). The prevalence of toxocariasis in this population was 7.3% (95% confidence interval [CI] 6.1% to 8.5%). The survey-weighted linear regression model showed that compared with participants who were toxocariasis seronegative, those who were seropositive had lower DSST z score (beta [β] = -0.12, 95% CI -0.22 to -0.01) and global cognition z score (β=-0.11, 95% CI -0.22 to -0.01), after controlling for age, sex, race/ethnicity, education, depressive symptoms, smoking status, body mass index, prevalent coronary heart disease, prevalent stroke, and systolic blood pressure, physical activity, and total cholesterol. CONCLUSIONS In our study, seropositive toxocariasis was independently and significantly associated with worse working memory, sustained attention, processing speed and global cognition in older adults. If this association is causal, public health measures to prevent human toxocariasis might help protect older adults' cognitive function.
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Affiliation(s)
- Ge Song
- Department of Natural Sciences, University of Houston-Downtown, Houston, Texas, USA
| | - Chao Yang
- The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Zhe Qu
- School of Nursing, Xu Zhou Medical College, Xuzhou, Jiangsu, China
| | - Xuechun Lin
- Department of Nutrition and Food hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Minhui Liu
- Central South University Xiangya School of Nursing, Changsha, Hunan Sheng, China
| | - Yanhong Wang
- School of Nursing, Lanzhou University, Lanzhou, Gansu, China
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Vojtechova I, Machacek T, Kristofikova Z, Stuchlik A, Petrasek T. Infectious origin of Alzheimer’s disease: Amyloid beta as a component of brain antimicrobial immunity. PLoS Pathog 2022; 18:e1010929. [PMCID: PMC9671327 DOI: 10.1371/journal.ppat.1010929] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The amyloid cascade hypothesis, focusing on pathological proteins aggregation, has so far failed to uncover the root cause of Alzheimer’s disease (AD), or to provide an effective therapy. This traditional paradigm essentially explains a mechanism involved in the development of sporadic AD rather than its cause. The failure of an overwhelming majority of clinical studies (99.6%) demonstrates that a breakthrough in therapy would be difficult if not impossible without understanding the etiology of AD. It becomes more and more apparent that the AD pathology might originate from brain infection. In this review, we discuss a potential role of bacteria, viruses, fungi, and eukaryotic parasites as triggers of AD pathology. We show evidence from the current literature that amyloid beta, traditionally viewed as pathological, actually acts as an antimicrobial peptide, protecting the brain against pathogens. However, in case of a prolonged or excessive activation of a senescent immune system, amyloid beta accumulation and aggregation becomes damaging and supports runaway neurodegenerative processes in AD. This is paralleled by the recent study by Alam and colleagues (2022) who showed that alpha-synuclein, the protein accumulating in synucleinopathies, also plays a critical physiological role in immune reactions and inflammation, showing an unforeseen link between the 2 unrelated classes of neurodegenerative disorders. The multiplication of the amyloid precursor protein gene, recently described by Lee and collegues (2018), and possible reactivation of human endogenous retroviruses by pathogens fits well into the same picture. We discuss these new findings from the viewpoint of the infection hypothesis of AD and offer suggestions for future research. More than a century after its discovery, Alzheimer’s disease (AD) remains incurable and mysterious. The dominant hypothesis of amyloid cascade has succeeded in explaining the key pathological mechanism, but not its trigger. Amyloid beta has been traditionally considered a pathological peptide, and its physiological functions remain poorly known. These knowledge gaps have contributed to repeated failures of clinical studies. The emerging infectious hypothesis of AD considers central nervous system (CNS) infection the primary trigger of sporadic AD. A closely connected hypothesis claims that amyloid beta is an antimicrobial peptide. In this review, we discuss the available evidence for the involvement of infections in AD, coming from epidemiological studies, post mortem analyses of brain tissue, and experiments in vitro and in vivo. We argue there is no unique “Alzheimer’s germ,” instead, AD is a general reaction of the CNS to chronic infections, in the milieu of an aged immune system. The pathology may become self-sustained even without continuous presence of microbes in the brain. Importantly, the infectious hypothesis leads to testable predictions. Targeting amyloid beta should be ineffective, unless the triggering pathogen and inflammatory response are addressed as well. Meticulous control of selected infections might be the best near-term strategy for AD prevention.
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Affiliation(s)
- Iveta Vojtechova
- National Institute of Mental Health, Klecany, Czech Republic
- Laboratory of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
- * E-mail: , (IV); , (TP)
| | - Tomas Machacek
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | | | - Ales Stuchlik
- National Institute of Mental Health, Klecany, Czech Republic
- Laboratory of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Tomas Petrasek
- National Institute of Mental Health, Klecany, Czech Republic
- Laboratory of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
- * E-mail: , (IV); , (TP)
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Wu Y, Duffey M, Alex SE, Suarez-Reyes C, Clark EH, Weatherhead JE. The role of helminths in the development of non-communicable diseases. Front Immunol 2022; 13:941977. [PMID: 36119098 PMCID: PMC9473640 DOI: 10.3389/fimmu.2022.941977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 08/01/2022] [Indexed: 12/15/2022] Open
Abstract
Non-communicable diseases (NCDs) like cardiovascular disease, chronic respiratory diseases, cancers, diabetes, and neuropsychiatric diseases cause significant global morbidity and mortality which disproportionately affect those living in low resource regions including low- and middle-income countries (LMICs). In order to reduce NCD morbidity and mortality in LMIC it is imperative to understand risk factors associated with the development of NCDs. Certain infections are known risk factors for many NCDs. Several parasitic helminth infections, which occur most commonly in LMICs, have been identified as potential drivers of NCDs in parasite-endemic regions. Though understudied, the impact of helminth infections on the development of NCDs is likely related to helminth-specific factors, including species, developmental stage and disease burden. Mechanical and chemical damage induced by the helminth in combination with pathologic host immune responses contribute to the long-term inflammation that increases risk for NCD development. Robust studies from animal models and human clinical trials are needed to understand the immunologic mechanisms of helminth-induced NCDs. Understanding the complex connection between helminths and NCDs will aid in targeted public health programs to reduce helminth-induced NCDs and reduce the high rates of morbidity that affects millions of people living in parasite-endemic, LMICs globally.
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Affiliation(s)
- Yifan Wu
- Department of Pediatrics, Division of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Megan Duffey
- Department of Pediatrics, Division of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States,Department of Medicine, Section of Infectious Diseases, Baylor College of Medicine, Houston, TX, United States
| | - Saira Elizabeth Alex
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Charlie Suarez-Reyes
- Department of Pediatrics, Division of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Eva H. Clark
- Department of Pediatrics, Division of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States,Department of Medicine, Section of Infectious Diseases, Baylor College of Medicine, Houston, TX, United States,National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Jill E. Weatherhead
- Department of Pediatrics, Division of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States,Department of Medicine, Section of Infectious Diseases, Baylor College of Medicine, Houston, TX, United States,National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States,*Correspondence: Jill E. Weatherhead,
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Identification of Toxocara canis Antigen-Interacting Partners by Yeast Two-Hybrid Assay and a Putative Mechanism of These Host-Parasite Interactions. Pathogens 2021; 10:pathogens10080949. [PMID: 34451413 PMCID: PMC8398310 DOI: 10.3390/pathogens10080949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/23/2021] [Accepted: 07/25/2021] [Indexed: 01/11/2023] Open
Abstract
Toxocara canis is a zoonotic roundworm that infects humans and dogs all over the world. Upon infection, larvae migrate to various tissues leading to different clinical syndromes. The host–parasite interactions underlying the process of infection remain poorly understood. Here, we describe the application of a yeast two-hybrid assay to screen a human cDNA library and analyse the interactome of T. canis larval molecules. Our data identifies 16 human proteins that putatively interact with the parasite. These molecules were associated with major biological processes, such as protein processing, transport, cellular component organisation, immune response and cell signalling. Some of these identified interactions are associated with the development of a Th2 response, neutrophil activity and signalling in immune cells. Other interactions may be linked to neurodegenerative processes observed during neurotoxocariasis, and some are associated with lung pathology found in infected hosts. Our results should open new areas of research and provide further data to enable a better understanding of this complex and underestimated disease.
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Gale SD, Hedges DW. Neurocognitive and neuropsychiatric effects of toxocariasis. ADVANCES IN PARASITOLOGY 2020; 109:261-272. [PMID: 32381201 DOI: 10.1016/bs.apar.2020.01.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Caused by the neuroinvasive nematodes Toxocara canis and Toxocara cati, human toxocariasis has a worldwide distribution with seroprevalence in humans associated with low socioeconomic status and low educational attainment. Third-stage Toxocara larvae can invade human tissues, including the brain and spine, where they can result in encephalitis, meningitis, and inflammation. Toxocara infection in animal models has been associated with cognitive and behavioural changes. In humans, preliminary cross-sectional research suggests that Toxocara seropositivity is associated with worse cognitive function in children and adults. Additional preliminary cross-sectional findings suggest associations between Toxocara seropositivity and neuropsychiatric function, including schizophrenia and neurologic conditions such as epilepsy. Given the widespread distribution of human toxocariasis and early evidence suggesting that it can be associated with cognitive and neuropsychiatric function in humans, additional research regarding the effects of toxocariasis on the human brain is required.
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Affiliation(s)
- Shawn D Gale
- Department of Psychology, Brigham Young University, Provo, UT, United States; The Neuroscience Centre, Brigham Young University, Provo, UT, United States.
| | - Dawson W Hedges
- Department of Psychology, Brigham Young University, Provo, UT, United States; The Neuroscience Centre, Brigham Young University, Provo, UT, United States
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Fan CK. Pathogenesis of cerebral toxocariasis and neurodegenerative diseases. ADVANCES IN PARASITOLOGY 2020; 109:233-259. [PMID: 32381200 DOI: 10.1016/bs.apar.2020.01.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Toxocara canis belongs to one of zoonotic parasites that commonly infects canines worldwide, and its eggs in host faeces may contaminate the food, water, soil and their fur as well as the larvae entrapped in the granuloma can infect paratenic hosts including mice and humans. Survivability of T. canis embryonated eggs under moist, cool conditions may be as long as 2-4 years or more. In paratenic hosts such as mice and humans, T. canis L3 larvae neither moult, grow, nor replicate and will wander through a number of internal organs in humans so as to cause Th2-dominant pathology in various internal organs as leading to neurotoxocariasis (NT), ocular toxocariasis (OT), or visceral larva migrans (VLM). Although the systemic immune response to T. canis has been widely reported, the immune response in the brain has received little attention. Differential cytokine expression and other brain injury-associated biomarkers or neurodegeneration-associated factors have been observed in infected versus uninfected outbred and inbred mice. Preliminary data have also suggested a possible link between significant memory impairment and cytokine production associated with T. canis infection in the hippocampus which has been long recognised as being responsible for learning and memory functions. Notably, it remains an enigma concerning cerebral invasion by T. canis larvae rarely induces a recognisable neurological syndrome or its involvement in neuropathological disorders in humans. Exploration of the relationship between host and parasite in the brain may elucidate the cryptic symptoms of human cerebral toxocariasis, with patients presenting with mental retardation, epilepsy, neurodegeneration and other central nervous system (CNS) disorders.
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Affiliation(s)
- Chia-Kwung Fan
- Department of Molecular Parasitology and Tropical Diseases, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Research Center of International Tropical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Tropical Medicine Division, International PhD Program in Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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11
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Li B, Zhao Y, Song M, Cui H, Feng X, Yang T, Fan HG. Role of c-Myc/chloride intracellular channel 4 pathway in lipopolysaccharide-induced neurodegenerative diseases. Toxicology 2019; 429:152312. [PMID: 31693917 DOI: 10.1016/j.tox.2019.152312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 09/21/2019] [Accepted: 10/16/2019] [Indexed: 12/21/2022]
Abstract
LPS-induced neuronal apoptosis leads to neurodegenerative diseases (NDs). However, the mechanisms underlying NDs pathogenesis remains unclear. The apoptotic response to activation of the c-Myc/chloride intracellular channel (CLIC4) pathway is directed through a mitochondrial pathway. In this study, we aimed to explore the c-Myc/CLIC4 pathway in the progression of NDs induced by lipopolysaccharide (LPS). In an in vivo experiment, the results of HE staining, transmission electron microscopic, immunofluorescence microscopy of cleaved caspase-3 and Bax and the increasing expression of apoptotic pathway related proteins in mitochondria showed that LPS (10 mg/kg) administration damaged mitochondrial and induced hippocampal neuron apoptosis. The Western blot and RT-PCR indicated that LPS induced the activation of c-Myc/CLIC4 pathway. Furthermore, in an in vitro experiment, PC12 cells were exposed to LPS to induce cell injuries to mimic the model of NDs. To further confirm the role of the c-Myc/CLIC4 pathway in LPS-induced neuronal apoptosis, the gene knockout of c-Myc and CLIC4 were performed by CRISPR/Cas9. The results of the flow cytometry assay and Annexin V-FITC/PI showed that knocking out c-Myc and CLIC4 significantly reduced cell apoptosis. The results of Western blot and dual immunofluorescence with Cyt c and TOM20 showed that knocking out c-Myc and CLIC4 significantly reduced the expression of mitochondrial apoptosis-related proteins. Our data confirmed that LPS-induced apoptosis is regulated by the activation of c-Myc/CLIC4 pathway. These results support further research mechanisms underlying neurodegenerative diseases and can provide effective pharmacodynamic targets for the clinical development of therapeutic drugs for neurodegenerative diseases.
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Affiliation(s)
- Bei Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, PR China
| | - Yuan Zhao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, PR China
| | - ManYu Song
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, PR China
| | - HaiLin Cui
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, PR China
| | - XiuJing Feng
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, PR China
| | - TianYuan Yang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, PR China
| | - Hong-Gang Fan
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, PR China.
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Santos LMD, de Moura MQ, Azevedo ML, Marques GA, Avila LFDC, Scaini CJ, Berne ME, Moreira ÂN, Conceição FR. Reactivity of recombinant Toxocara canis TES-30/120 in experimentally infected mice. Parasite Immunol 2019; 40:e12568. [PMID: 29938803 DOI: 10.1111/pim.12568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/20/2018] [Indexed: 01/29/2023]
Abstract
AIM While the use of recombinant antigens is being widely investigated in the diagnosis of human toxocariasis, relatively little attention has been given to animal diagnostic models. For this reason, this study aimed to investigate the diagnosis potential of Toxocara canis TES-30 and TES-120 recombinant antigens in mice, the animal model for toxocariasis studies. METHODS AND RESULTS Serum samples obtained from mice infected with T. canis or Toxocara cati were tested by indirect ELISA using T. canis TES-30 and TES-120 recombinant antigens produced in Escherichia coli. 90% of the samples reacted with rTES-30, whereas there was almost no reactivity with rTES-120. CONCLUSION Despite rTES-120 being a good antigen for diagnosis in humans, it could not reproduce its reactivity in this animal model. As rTES-30 has good reactivity in mice, it is a valuable tool for diagnosis.
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Affiliation(s)
- Lucas Moreira Dos Santos
- Programa de Pós-Graduação em Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brasil
| | - Micaele Quintana de Moura
- Programa de Pós-Graduação em Parasitologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brasil
| | - Morgana Lüdtke Azevedo
- Programa de Pós-Graduação em Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brasil
| | - Giuli Argou Marques
- Programa de Pós-Graduação em Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brasil
| | - Luciana Farias da Costa Avila
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Rio Grande, Rio Grande, Rio Grande do Sul, Brasil
| | - Carlos James Scaini
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Rio Grande, Rio Grande, Rio Grande do Sul, Brasil
| | - Maria Elisabeth Berne
- Programa de Pós-Graduação em Parasitologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brasil
| | - Ângela Nunes Moreira
- Programa de Pós-Graduação em Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brasil
| | - Fabricio Rochedo Conceição
- Programa de Pós-Graduação em Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brasil
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Chou CM, Fan CK. Significant apoptosis rather autophagy predominates in astrocytes caused by Toxocara canis larval excretory-secretory antigens. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2018; 53:250-258. [PMID: 30033092 DOI: 10.1016/j.jmii.2018.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 06/20/2018] [Accepted: 06/22/2018] [Indexed: 01/25/2023]
Abstract
BACKGROUND/PURPOSE Toxocariasis is a worldwide parasitic zoonosis and mainly caused by Toxocara canis. Humans can be infected by accidental ingestion of T. canis embryonated ova through contacting with contaminated food, water, or encapsulated larvae in paratenic hosts' viscera or meat. Since humans are the paratenic host of T. canis, the wandering and neuroinvasive larvae can cause mechanical tissue damage and the excretory-secretory antigens (TcES Ag) might induce neuroinflammatory responses in the brain. Human cerebral toxocariasis (CT) has been reported to cause several neurological symptoms and may develop into neurodegenerative diseases. However, the roles of astrocytes involved in the pathogenesis of CT remained largely unclear. METHODS This study intended to investigate the cytotoxic effects of TcES Ag on astrocytes as assessed by apoptosis and autophagy expression. RESULTS Our results showed TcES Ag treatment reduced cell viability and caused morphological changes. Expressions of autophagy associated proteins including Beclin 1, phosphor-mTOR and LC3-Ⅱ were not significantly changed; however, p62 as well as the cell survival protein, mTOR, was concomitantly decreased in TcES Ag treatment. Significantly accelerated cleaved caspase-3 and cytochrome c expression as well as enhanced caspase-9 and caspase-8 activation were found in astrocytes with TcES Ag treatment. Caspase-3 activity and apoptotic cells numbers were also increased as detected by fluorescence microscopy. CONCLUSION We concluded that TcES Ag may trigger astrocytes apoptosis predominantly through intrinsic and extrinsic pathways rather autophagy, revealing a novel role of astrocytes in the pathogenesis of CT.
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Affiliation(s)
- Chia-Mei Chou
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, 250 Wuxing St., Taipei 11031, Taiwan; Department of Molecular Parasitology and Tropical Diseases, School of Medicine, College of Medicine, Taipei Medical University, 250 Wuxing St., Taipei 11031, Taiwan
| | - Chia-Kwung Fan
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, 250 Wuxing St., Taipei 11031, Taiwan; Department of Molecular Parasitology and Tropical Diseases, School of Medicine, College of Medicine, Taipei Medical University, 250 Wuxing St., Taipei 11031, Taiwan; Research Center of International Tropical Medicine, College of Medicine, Taipei Medical University, 250 Wuxing St., Taipei 11031, Taiwan; Tropical Medicine Division, International PhD Program in Medicine, College of Medicine, Taipei Medical University, 250 Wuxing St., Taipei 11031, Taiwan.
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