The prevalence of pinworm infection in the pre-school children of Taipei is extremely low and decreasing. Good hand washing habit should be an important preventive measure. Transmission of this infection in pre-school children may occur in the family through their school-age siblings.
Angiostrongylus cantonensis, the rat lungworm, is an important aetiologic agent of eosinophilic meningitis and meningoencephalitis in humans. Co-culturing astrocytes with soluble antigens of A. cantonensis activated the Sonic hedgehog (Shh) signalling pathway and inhibited the apoptosis of astrocytes via the activation of Bcl-2. This study was conducted to determine the roles of the Shh signalling pathway, apoptosis, and oxidative stress in astrocytes after treatment with excretory-secretory products (ESP) from A. cantonensis fifth-stage larvae. Although astrocyte viability was significantly decreased after ESP treatment, the expression of Shh signalling pathway related proteins (Shh, Ptch-1 and Gli-1) was significantly increased. However, apoptosis in astrocytes was significantly decreased after activation of the Shh signalling pathway. Moreover, superoxide and hydrogen superoxide levels in astrocytes were significantly reduced after the activation of Shh pathway signalling due to increasing levels of the antioxidants catalase and superoxide dismutase. These findings indicate that the anti-apoptotic effects of the Shh signalling pathway in the astrocytes of mice infected with A. cantonensis are due to reduced levels of oxidative stress caused by the activation of antioxidants.
Pathological changes in the brains of the treated rabbits are more severe than those without albendazole treatment, suggesting that the drug may not be very suitable for the treatment of cerebral angiostrongyliasis.
Background: Angiostrongylus cantonensis is an important causative agent of eosinophilic meningitis and eosinophilic meningoencephalitis in humans. Previous studies have shown that the Sonic hedgehog (Shh) signaling pathway may reduce cell apoptosis by inhibiting oxidative stress in A. cantonensis infection. In this study, we investigated the relationship between cytokine secretion and Shh pathway activation after treatment with excretory/secretory products (ESP) of fifth-stage larval A. cantonensis (L5).
The present study demonstrated that gastrointestinal parasitic infections occur frequently in dairy cattle around Taiwan, especially protozoan infections. The results indicated that a superior management system and regular anthelmintic treatment should be used for the control of parasitic infections in dairy cattle farms.
Stomach intubation is the most common method used in the experimental infection of animals with Angiostrongylus cantonensis. In order to compare the effectiveness of other possible transmission methods, groups of BALB/c mice were given infective third-stage larvae of A. cantonensis by different routes including intraperitoneal or subcutaneous injections, and penetration of anal mucosa, vaginal mucosa, conjunctival mucosa, lacerated skin, unabraded skin, foot pad and tail skin, while stomach intubation was used as control. Recovery of fifth-stage larvae was higher in mice inoculated with third-stage larvae subcutaneously. Successful infections were established through all experimental transmission routes except tail skin penetration. This study suggests that oral infection may not be the only route for the transmission of human angiostrongyliasis, and subcutaneous infection may be a better method for experimental infection.
BACKGROUND
Angiostrongyliasis is caused by the nematode
Angiostrongylus
cantonensis
and can lead to eosinophilic meningitis and
meningoencephalitis in humans. The young adult worms play central pathogenic
roles in the central nervous system (CNS); however, the underlying mechanism
is unclear. Excretory-secretory products (ESPs) are good investigation
targets for studying the relationship between a host and its parasite.
OBJECTIVES
We aimed to profile, identify, and characterise the proteins in the ESPs of
A. cantonensis
young adults.
METHODS
The ESPs of young adult worms were collected from culture medium after
incubation ranging from 24 to 96 h. Proteomic and bioinformatics analyses
were performed to characterise the ESPs.
FINDINGS
A total of 51 spots were identified, and the highly expressed proteins
included two protein disulphide isomerases, one calreticulin, and three
uncharacterised proteins. Subsequently, approximately 254 proteins were
identified in the ESPs of
A. cantonensis
young adults via
liquid chromatography-mass spectrometry (LC-MS/MS) analysis, and these were
further classified according to their characteristics and biological
functions. Finally, we identified the immunoreactive proteins from a
reference map of ESPs from
A. cantonensis
young adults.
Approximately eight proteins were identified, including a protein disulphide
isomerase, a putative aspartic protease, annexin, and five uncharacterised
proteins. The study established and identified protein reference maps for
the ESPs of
A. cantonensis
young adults.
MAIN CONCLUSIONS
The identified proteins may be potential targets for the development of
diagnostic or therapeutic agents for human angiostrongyliasis.
Angiostrongylus cantonensis infection may cause elevation of ROS and antioxidants in the CSF of infected mice. Astrocytes may protect the surrounding neurons from oxidative stress-induced cell death by secreting Sonic hedgehog (Shh) via the PI3-K/AKT/Bcl-2 pathway. This study was conducted to determine the role of the Shh signaling pathway in A. cantonensis-infected BABL/c mice by coculturing astrocytes with living fifth-stage larvae or soluble antigens. The Shh pathway was activated with corresponding increases in the level of the Shh. Glial fibrillary acidic protein (GFAP) and Shh were increased in astrocyte cocultured with living fifth-stage larvae or soluble antigens. The survival of astrocytes pretreated with Shh was significantly elevated in cocultures with the antigens but reduced by its inhibitor cyclopamine. The expression of GRP78 and Bcl-2 was significantly higher in astrocytes pretreated with recombinant Shh. These findings suggest that the expression of Shh may inhibit cell death by activating Bcl-2 through a GRP78-dependent pathway.
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