The neuroprotective potential of curcumin on T. Spiralis infected mice.

BACKGROUND: Trichinella spiralis can affect the brain by inducing inflammatory and vascular changes. Drug management with the antiparasitic drug albendazole can be enhanced by natural compounds such as curcumin. The potential benefit of curcumin as an adjuvant to albendazole in the management of cerebral affection during experimental T. spiralis infection was evaluated. Animals received either curcumin 150 mg/Kg, albendazole 50 mg/Kg or a combination of both drugs. Animal groups receiving treatment were compared with infected and non-infected control groups. Blood levels of reduced glutathione (GSH) and dopamine were measured, and brain tissue expression of cyclooxygenase-2 enzyme (COX-2) and CD34 was assessed by immunohistochemistry. RESULTS: T. spiralis infection resulted in a state of oxidative stress, which was improved by albendazole and curcumin. Also, both drugs restored the peripheral dopamine level, which was decreased in infected non-treated mice. Curcumin was also found to be efficient in improving brain pathology and reducing local COX-2 and CD 34 expression. CONCLUSIONS: Inflammatory and pathological changes during neurotrichinosis can be improved by the addition of curcumin to conventional anti-parasitic drugs.

A novel trypsin of Trichinella spiralis mediates larval invasion of gut epithelium via binding to PAR2 and activating ERK1/2 pathway.

BACKGROUND: Proteases secreted by Trichinella spiralis intestinal infective larvae (IIL) play an important role in larval invasion and pathogenesis. However, the mechanism through which proteases mediate larval invasion of intestinal epithelial cells (IECs) remains unclear. A novel T. spiralis trypsin (TsTryp) was identified in IIL excretory/secretory (ES) proteins. It was an early and highly expressed protease at IIL stage, and had the potential as an early diagnostic antigen. The aim of this study was to investigate the biological characteristics of this novel TsTryp, its role in larval invasion of gut epithelium, and the mechanisms involved. METHODOLOGY/PRINCIPAL FINDING: TsTryp with C-terminal domain was cloned and expressed in Escherichia coli BL21 (DE3), and the rTsTryp had the enzymatic activity of natural trypsin, but it could not directly degrade gut tight junctions (TJs) proteins. qPCR and western blotting showed that TsTryp was highly expressed at the invasive IIL stage. Immunofluorescence assay (IFA), ELISA and Far Western blotting revealed that rTsTryp specifically bound to IECs, and confocal microscopy showed that the binding of rTsTryp with IECs was mainly localized in the cytomembrane. Co-immunoprecipitation (Co-IP) confirmed that rTsTryp bound to protease activated receptors 2 (PAR2) in Caco-2 cells. rTsTryp binding to PAR2 resulted in decreased expression levels of ZO-1 and occludin and increased paracellular permeability in Caco-2 monolayers by activating the extracellular regulated protein kinases 1/2 (ERK1/2) pathway. rTsTryp decreased TJs expression and increased epithelial permeability, which could be abrogated by the PAR2 antagonist AZ3451 and ERK1/2 inhibitor PD98059. rTsTryp facilitated larval invasion of IECs, and anti-rTsTryp antibodies inhibited invasion. Both inhibitors impeded larval invasion and alleviated intestinal inflammation in vitro and in vivo. CONCLUSIONS: TsTryp binding to PAR2 activated the ERK1/2 pathway, decreased the expression of gut TJs proteins, disrupted epithelial integrity and barrier function, and consequently mediated larval invasion of the gut mucosa. Therefore, rTsTryp could be regarded as a potential vaccine target for blocking T. spiralis invasion and infection.

Trichinella spiralis cathepsin B bound and degraded host's intestinal type I collagen.

Trichinellosis is a zoonotic parasitic disease that poses threats to human health, the meat industry, food safety, and huge financial losses. The critical stage of Trichinella spiralis (T. spiralis) infection is the invasion of intestinal larvae into the host's intestinal epithelial cells (IECs). T. spiralis Cathepsin B (TsCB) specifically interacts with IECs to facilitate the invasion of larvae. This study aims to look at how TsCB affects mouse IECs. TsCB was successfully cloned, expressed, and characterized, demonstrating its natural cysteine protease hydrolysis activity. A total of 140 proteins that interact with rTsCB were identified by GST pull-down combined with LC-MS/MS, including type I collagen, an essential component of the host's intestinal epithelial barrier system and intimately related to intestinal epithelial damage. TsCB transcription and expression levels rise, whereas type I collagen in the host's intestinal mucosa declines when the T. spiralis larvae invaded. Besides, it was discovered that TsCB bound to and degraded type I collagen of the host's intestine. This research can serve as a foundation for clarifying how T. spiralis invades the host's intestinal barrier and might provide information on potential targets for the creation of novel treatments to treat parasite illnesses.

Effects of Trichinella spiralis and its serine protease inhibitors on autophagy of host small intestinal cells.

In eukaryotes, autophagy is induced as an innate defense mechanism against pathogenic microorganisms by self-degradation. Although trichinellosis is a foodborne zoonotic disease, there are few reports on the interplay between Trichinella spiralissurvival strategies and autophagy-mediated host defense. Therefore, this study focused on the association between T. spiralis and autophagy of host small intestinal cells. In this study, the autophagy-related indexes of host small intestinal cells after T. spiralis infection were detected using transmission electron microscopy, hematoxylin and eosin staining, immunohistochemistry, quantitative real-time polymerase chain reaction, and Western blotting. The results showed that autophagosomes and autolysosomes were formed in small intestinal cells, intestinal villi appeared edema, epithelial compactness was decreased, microtubule-associated protein 1A/1B-light chain 3B (LC3B) was expressed in lamina propria stromal cells of small intestine, and the expression of autophagy-related genes and proteins was changed significantly, indicating that T. spiralis induced autophagy of host small intestinal cells. Then, the effect of T. spiralis on autophagy-related pathways was explored by Western blotting. The results showed that the expression of autophagy-related pathway proteins was changed, indicating that T. spiralis regulated autophagy by affecting autophagy-related pathways. Finally, the roles of T. spiralis serine protease inhibitors (TsSPIs), such as T. spiralis Kazal-type SPI (TsKaSPI) and T. spiralis Serpin-type SPI (TsAdSPI), were further discussed in vitro and in vivo experiments. The results revealed that TsSPIs induced autophagy by influencing autophagy-related pathways, and TsAdSPI has more advantages. Overall, our results indicated that T. spiralis induced autophagy of host small intestinal cells, and its TsSPIs play an important role in enhancing autophagy flux by affecting autophagy-related pathways. These findings lay a foundation for further exploring the pathogenesis of intestinal dysfunction of host after T. spiralis infection, and also provide some experimental and theoretical basis for the prevention and treatment of trichinellosis.

In vitro knockdown of TsDNase II-7 suppresses Trichinella spiralis invasion into the host's intestinal epithelial cells.

Trichinella spiralis (T. spiralis) adult-specific deoxyribonuclease II-7 (TsDNase II-7), a member of the DNase II-like nuclease family with no DNase II activity, was identified in the excretory-secretory (ES) products of adult worms (AWs). However, its biological functions are still unclear. Our previous study revealed that TsDNase II-7 is located around the infection site in the intestinal tissue, speculating that it was involved in the T. spiralis invasion of host intestinal epithelial cells (IECs). This study aimed to use RNA interference to verify our speculation that TsDNase II-7 in 3-day old adult T. spiralis (Ad3) plays a role in intestinal invasion. TsDNase II-7-specific small interfering RNAs (siRNAs) were delivered into muscle larvae (MLs) to knockdown TsDNase II-7 expression by electroporation. Twenty-four hours later, the MLs transfected with 2 µM siRNA-841 exhibited decreased in TsDNase II-7 transcription and expression as compared to the control MLs. The knockdown of TsDNase II-7 expression did not affect ML viability, and the low expression of TsDNase II-7 still maintained in Ad3 recovered from TsDNase II-7-RNAi-ML infected mice, resulting in a weakened ability of Ad3 to invade intestinal epithelial cells (IECs). These results indicated that knockdown of TsDNase II-7 gene expression via RNA interference (RNAi) suppressed adult worm invasion and confirmed that TsDNase II-7 plays a crucial role during the intestinal phase of T. spiralis infections, which provided new candidate for vaccine development of T. spiralis.

Trichinella spiralis: Knockdown of gamma interferon inducible lysosomal thiol reductase (GILT) results in the reduction of worm burden.

Trichinella spiralis is mammalian skeletal muscles parasite which may cause trichinellosis in animals and humans. Gamma interferon inducible lysosomal thiol reductase (GILT) is a widespread superfamily which plays key role in processing and presentation of MHC class II restricted antigen by catalyzing disulfide bond reduction. There are no reports about GILT in T. spiralis. In present study, GILT from T. spiralis (Tsp-GILT) was cloned, analyzed by multiple-sequence alignment, and predicted by 3D structure model. Recombinant Tsp-GILT (about 46 kDa) was efficiently expressed in Escherichia coli and thiol reductase activity suggested that in acidic environment the addition of a reducing agent is needed. Soaking method was used to knockdown expression of Tsp-GILT using small interference RNA (siRNA). Immunofluorescence assay confirmed the transformation of siRNA into muscle larva (ML) and new born larva (NBL). Quantitative real time-PCR (QRT-PCR) analysis revealed that transcription level of Tsp-GILT mRNA can be up-regulated by stimulation of mouse IFN-γ and down-regulated by siRNA2 in vitro. NBLs soaked with siRNA2 showed 32.3% reduction in the generation of MLs. MLs soaked with siRNA2 showed 26.2% reduction in the next generation of MLs, but no significant effect was observed on adult worms or NBLs. These findings concluded that GILT may play important roles in the development of T. spiralis parasite.

Harnessing immunomodulatory mechanisms of Trichinella spiralis to design novel nanomedical approaches for restoring self-tolerance in autoimmunity.

The rapid increase in the prevalence of autoimmune diseases in recent decades, especially in developed countries, coincided with improved living conditions and healthcare. Part of this increase could be ascribed to the lack of exposure to infectious agents like helminths that co-evolved with us and display potent immune regulatory actions. In this review we discussed many investigations, including our own, showing that Trichinella spiralis via its excretory-secretory products attenuate Th1/Th17 immunopathological response in autoimmunity and potentiate the protective Th2 and or regulatory T cell response, acting as an effective induction of tolerogenic dendritic cells (DCs), and probably mimicking the autoantigen in some diseases. A recent discovery of T. spiralis extracellular vesicles (TsEVs) suggested that inducing a complex regulation of the immune response requires simultaneous delivery of different signals in nano-sized packages. Indeed, different artificial nanomedical approaches discussed here suggested that co-delivery of multiple signals via nanoparticles is the most promising strategy for the treatment of autoimmune diseases. Although a long way is ahead of us before we could completely replicate natural nano-delivery systems which are both safe and potent in restoring self-tolerance, a clear path is being opened from a careful examination of parasite-host interactions.

Galectin-Receptor Interactions Regulates Cardiac Pathology Caused by Trichinella spiralis Infection.

The parasitic nematode Trichinella spiralis causes trichinellosis, a serious food-borne parasitic zoonosis worldwide. Infection with T. spiralis may also cause myocarditis. In the present study, we used mouse models to assess the impact of blockage of galectin-receptor interactions by α-lactose on cardiac immunopathology during acute T. spiralis experimental infection. Our data demonstrated that, after T. spiralis infection, blockage of galectin-receptor interactions resulted in cardiac dysfunction detected by transthoracic conventional echocardiography, and increased serum Gal-3 level, a biomarker of myocardial damage. In addition, there were increased eosinophil number in peripheral blood, and increased eosinophil infiltration in the heart and spleen tissues accompanied with increased mRNA levels of eosinophil granule proteins (including eosinophil cationic protein (ECP) and eosinophil peroxidase (EPO)) and IL-5 in these organs; increased cardiac fibrosis accompanied with increased Gal-3 and collagen 1 expressions in the hearts of mice with blockage of galectin-receptor interactions after T. spiralis infection. Correlation analysis showed that significant positive correlations existed between the mRNA levels of Gal-3 and ECP/EPO/eosinophil major basic protein/IL-5/CCL11/CCR3/α-SMA/collagen 1 in the hearts of both T. spiralis-infected mice and T. spiralis-infected mice with blockage of galectin-receptor interactions. Our data suggest that galectin-receptor interactions play a pivotal role during acute T. spiralis infection, and lack of galectin-receptor interactions upregulates Gal-3 which, in turn, leads to elevated heart eosinophil recruitment, exacerbated heart pathology and fibrosis, and heart functional damage.

Purinergic P2X7 Receptor Mediates the Elimination of Trichinella spiralis by Activating NF-κB/NLRP3/IL-1ß Pathway in Macrophages.

Trichinellosis is one of most neglected foodborne zoonoses worldwide. During Trichinella spiralis infection, the intestinal immune response is the first line of defense and plays a vital role in the host's resistance. Previous studies indicate that purinergic P2X7 receptor (P2X7R) and pyrin domain-containing protein 3 (NLRP3) inflammasome are involved in the intestinal immune response in T. spiralis infection. However, the precise role of P2X7R and its effect on NLRP3 remains largely underdetermined. In this study, we aimed to investigate the role of P2X7R in the activation of NLRP3 in macrophages during the intestinal immune response against T. spiralis We found that T. spiralis infection upregulated expression of P2X7R and activation of NLRP3 in macrophages in mice. In vivo, P2X7R deficiency resulted in increased intestinal adult and muscle larval burdens, along with decreased expression of NLRP3/interleukin-1ß (IL-1ß) in macrophages from the infected mice with T. spiralis In In vitro experiments, P2X7R blockade inhibited activation of NLRP3/IL-1ß via NF-κB and thus reduced the capacity of macrophages to kill newborn larvae of T. spiralis These results indicate that P2X7R mediates the elimination of T. spiralis by activating the NF-κB/NLRP3/IL-1ß pathway in macrophages. Our findings contribute to the understanding of the intestinal immune mechanism of T. spiralis infection.

Oxidative stress mediated apoptotic potential of mefloquine on experimental trichinellosis.

Conventional anthelmintics such as albendazole could not achieve complete cure of trichinellosis till now. The antimalarial mefloquine mediates oxidative stress and disrupts lysosomal functions leading to cell death. Therefore, the aim of this work was to investigate the effect of mefloquine on experimental acute and chronic trichinellosis and to clarify the possible mechanisms of such effects. Mice were divided into four groups; Group I: Uninfected untreated control (20 mice); Group II: Infected untreated control (40 mice); Group III: infected and treated with albendazole (400 mg/kg) (40 mice); Group IV: infected and treated with mefloquine (300 mg/kg) (40 mice). All infected treated groups were equally subdivided into 2 subgroups; (a) treated on the 2nd day post infection (dpi) for 3 days, (b) treated on the 35th dpi for 5 days. Parasitological adults and larvae counting besides immunohistopathological examination of intestines and muscles were done. Biochemical assay of oxidant/antioxidant status, apoptotic, cytoprotective and inflammatory biomarkers in intestinal and muscle homogenates were achieved. Results showed that both albendazole and mefloquine significantly reduced adults and larvae counts with higher efficacy of albendazole in the intestinal phase and superiority of mefloquine in the muscle phase. The superiority of mefloquine was indicated by increased inflammatory immune infiltration and decreased anti-apoptotic immunohistochemical markers expression in both jejunal and muscle tissues. Biochemically, mefloquine treatment showed highly significant oxidative, apoptotic and inflammatory effects. So, our results suggest that mefloquine might be a superior treatment for chronic trichinellosis.

Infection by the parasitic helminth Trichinella spiralis activates a Tas2r-mediated signaling pathway in intestinal tuft cells.

The parasitic helminth Trichinella spiralis, which poses a serious health risk to animals and humans, can be found worldwide. Recent findings indicate that a rare type of gut epithelial cell, tuft cells, can detect the helminth, triggering type 2 immune responses. However, the underlying molecular mechanisms remain to be fully understood. Here we show that both excretory-secretory products (E-S) and extract of T. spiralis can stimulate the release of the cytokine interleukin 25 (IL-25) from the mouse small intestinal villi and evoke calcium responses from tuft cells in the intestinal organoids, which can be blocked by a bitter-taste receptor inhibitor, allyl isothiocyanate. Heterologously expressed mouse Tas2r bitter-taste receptors, the expression of which is augmented during tuft-cell hyperplasia, can respond to the E-S and extract as well as to the bitter compound salicin whereas salicin in turn can induce IL-25 release from tuft cells. Furthermore, abolishment of the G-protein γ13 subunit, application of the inhibitors for G-protein αo/i, Gßγ subunits, and phospholipase Cß2 dramatically reduces the IL-25 release. Finally, tuft cells are found to utilize the inositol triphosphate receptor type 2 (Ip3r2) to regulate cytosolic calcium and thus Trpm5 activity, while potentiation of Trpm5 by a sweet-tasting compound, stevioside, enhances tuft cell IL-25 release and hyperplasia in vivo. Taken together, T. spiralis infection activates a signaling pathway in intestinal tuft cells similar to that of taste-bud cells, but with some key differences, to initiate type 2 immunity.

Molecular characterization of a 31 kDa protein from Trichinella spiralis and its induced immune protection in BALB/c mice.

BACKGROUND: Trichinella spiralis is an important foodborne zoonotic parasite and it is necessary to develop a vaccine in order to interrupt transmission from animals to humans. A 31 kDa protein from T. spiralis (Ts31) is an antigen targeted by protective antibodies, and Ts31 contains a domain of trypsin-like serine protease that might have the function of serine protease. The purpose of this study was to investigate the molecular characteristics of Ts31 and its induced immune protection. METHODS: Expression and localization of Ts31 in various T. spiralis phases were investigated using qPCR and immunofluorescent test (IFT). The specific binding between Ts31 and intestinal epithelium cells (IECs) was analyzed by Far-Western blotting, ELISA and IFT, and the cellular localization of binding sites was examined on confocal microscopy. The mice were subcutaneously vaccinated with recombinant Ts31 protein (rTs31), serum specific IgG was determined by ELISA, and immune protection induced by immunization with rTs31 was evaluated. Inhibition of anti-rTs31 IgG on IL1 invasion of IECs and ADCC-mediated killing of newborn larvae (NBL) was also determined. RESULTS: Ts31 was expressed at different life-cycle stages and located principally at the stichosome and cuticle of this parasite. rTs31 was capable to specially bond to IECs, and binding site was located in the cytoplasm of IECs. Immunization of mice with rTs31 elicited a significant humoral response and protection, as demonstrated by a 56.93% reduction of adult worms at 6 days post-infection (dpi) and a 53.50% reduction of muscle larvae at 42 dpi after larval challenge. Anti-rTs31 antibodies impeded T. spiralis penetration of enterocytes in a dose-dependent pattern, and participated in the destruction of NBL by an ADCC-mediated manner. CONCLUSIONS: Ts31 facilitated the T. spiralis penetration of intestinal epithelium, which could make it a vaccine candidate target molecule against Trichinella infection.

Identification of a host collagen inducing factor from the excretory secretory proteins of Trichinella spiralis.

BACKGROUND: In a previous study, we found that Trichinella spiralis muscle larva excretory and secretory proteins (ES-P) most likely activate collagen synthesis via TGF-ß/Smad signaling, and this event could influence collagen capsule formation. METHODOLOGY/PRINCIPAL FINDINGS: In order to identify the specific collagen inducing factor, ES-P was fractionated by a Superdex 200 10/300 GL column. We obtained three large fractions, F1, F2, and F3, but only F3 had collagen gene inducing ability. After immunoscreening, 10 collagen inducing factor candidates were identified. Among them, TS 15-1 and TS 15-2 were identical to the putative trypsin of T. spiralis. The deduced TS 15-1 (M.W. = 72 kDa) had two conserved catalytic motifs, an N-terminal Tryp_SPc domain (TS 15-1n) and a C-terminal Tryp_SPc domain (TS 15-1c). To determine their collagen inducing ability, recombinant proteins (rTS 15-1n and rTS 15-1c) were produced using the pET-28a expression system. TS 15-1 is highly expressed during the muscle larval stage and has strong antigenicity. We determined that rTS 15-1c could elevate collagen I via activation of the TGF-ß1 signaling pathway in vitro and in vivo. CONCLUSION/SIGNIFICANCE: In conclusion, we identified a host collagen inducing factor from T. spiralis ES-P using immunoscreening and demonstrated its molecular characteristics and functions.

Killing the muscular larvae of Trichinella spiralis and the anti-fibrotic effect of the combination of Wortmannilatone F and recombinant G31P in a murine model of trichinellosis.

Although trichinosis is one of the global food-borne parasitic diseases and is considered an emerging/re-emerging disease that has been reported in 66 countries, the drugs for its prevention and treatment have not been thoroughly investigated. Wortmannilactone F (WF) has been reported as a blocker of the helminth mitochondria respiratory chain by inhibiting NADH-fumarate reductase in the mitochondrial inner membrane. CXCL8 (3-73) K11R/G31 P(G31 P) has been reported as a CXCL8 analogue that has the affinity to CXCR1 and CXCR2. Male BALB/c mice were orally fed with 150 infective Trichinella spiralis (T. spiralis) larvae. Then, T. spiralis-infected mice were treated with WF and G31 P. The number and morphological analysis of encapsulated T. spiralis, collagen fiber accumulation, and the expression of angiogenic factors were investigated. WF and G31 P dramatically decreased the numbers of encapsulation, decreased collagen fibers, and suppressed angiogenesis. These findings indicate that the combination of WF and G31 P is a potential therapeutic strategy of Trichinellosis.

T-Bet independent development of IFNγ secreting natural T helper 1 cell population in the absence of Itk.

Th1, Th2, Th9 and Th17 cells are conventional CD4+ effector T cells identified as secretors of prototypical cytokines IFNγ, IL4, IL9, and IL-17A respectively. Recently, populations of natural Th17 and Th1 cells (nTh17 and nTh1) with innate-like phenotype have been identified in the thymus that are distinct from conventional Th17 and Th1 cells. The absence of the Tec family kinase Interleukin-2 inducible T cell kinase (Itk) results in T cell immunodeficiency in mice and humans. Here we show that Itk negatively regulates the development of nTh1 cells that express IFNγ in a Tbet independent manner, and whose expansion can be enhanced by IL4. Furthermore, we show that robust induction of IL4 responses during Trichinella spiralis infection enhance the presence of nTh1 cells. We conclude T cell receptor signaling via Itk controls the development of natural Th1 cells, which are expanded by the presence of IL4.

Paraoxonase-1 activity is related to Trichinella spiralis-induced hepatitis in rats.

BACKGROUND: Little is known about the potential adverse effects of a chronic zoonotic nematode Trichinella spiralis infection on hepatic inflammation and its relationship to paraoxonase (PON)-1 and butyrylcholinesterase (BuChE) activities. Therefore, we aimed to examine the effects of T. spiralis infection on hepatic synthesis of PON1. METHODS: Wistar rats were infected with 2500 first-stage larvae (L1) of T. spiralis, and serum PON1 and BuChE activities were evaluated. Hepatic expression levels of PON1, BuChE and various cytokines and chemokines [interleukin (IL)-1, IL-4, IL-6, IL-10, tumour necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1α, and transforming growth factor (TGF)-ß1] were evaluated for up to 9 weeks post-infection (p.i.). The effect of these changes on the degree of hepatic apoptosis was also investigated. RESULTS: Trichinella spiralis infection in rats induced significant decreases in serum PON1 activities from day 2 until week 7 p.i. and BuChE activity starting from day 4 until 2 weeks p.i. Moreover, T. spiralis infection increased serum pro-inflammatory cytokines IL-1, IL-6 and TNF-α as well as chemokines MCP-1, MIP-1α and TGF-ß1 during the enteral phase of the parasite life cycle. The anti-inflammatory cytokines IL-4 and IL-10 showed significant increases during the enteral phase for the former and the muscle phase for the latter. These were associated with hepatic inflammation and apoptosis. These events typically decreased hepatic PON1 and BuChE mRNA expression. CONCLUSIONS: Immune responses mounted against T. spiralis infection in rats were associated with hepatic inflammation and a subsequent decrease in serum PON1 and BuChE activities.

Persistent alterations in colonic afferent innervation in a rat model of postinfectious gut dysfunction: Role for changes in peripheral neurotrophic factors.

BACKGROUND: Visceral hypersensitivity in the inflamed gut is related partly to the effects of peripheral neurotrophic factors (NTFs) on local afferent neurons. However, alterations in sensory afferents of distant areas remain unexplored. Using the Trichinella spiralis infection model, which causes a jejunitis, we investigated the remodeling of colonic afferents and the potential role of NTFs. METHODS: Rats were infected with T. spiralis. Inflammatory-like changes, mucosal mast cells (MMCs) dynamics, and expression of nerve growth factor and glial cell line-derived NTFs (glial cell-derived neurotrophic factor, artemin, and neurturin) were determined in the colon up to day 30 postinfection. Functional responses of colonic afferents were determined assessing changes in the expression of sensory-related markers in thoracolumbar (TL)/lumbosacral (LS) dorsal root ganglias (DRGs) following intracolonic capsaicin. KEY RESULTS: Trichinella spiralis induced an inflammatory-like response within the colon, partly resolved at day 30 postinfection, except for a persistent MMC infiltrate. While the jejunum of infected animals showed an up-regulation in the expression of NTFs, a transitory down-regulation was observed in the colon. Overall, T. spiralis effects on DRGs gene expression were restricted to a transient down-regulation of TPRV1. Stimulation with intracolonic capsaicin induced a down-regulation of TRPV1 levels in TL and LS DRGs, an effect enhanced in LS DRGs of infected animals, regardless the postinfection time considered. CONCLUSIONS & INFERENCES: During intestinal inflammation, spread morphological and functional alterations, including remodeling of visceral afferents, are observed outside the primary region affected by the insult. Similar mechanisms might be operating in states of widespread alterations of visceral sensitivity.

[Effect of exogenous nitric oxide on antioxidants from mice infected with Trichinella spiralis].

OBJECTIVE: To study the effect of exogenous nitric oxide donor sodium nitroprusside (SNP) on antioxidant enzymes activities and lipid peroxidation of mice infected with Trichinella spiralis. METHODS: BALB/c mice were infected with T. spiralis separated by the digestion method. Forty-two days post-infection, the peripheral blood and hepatic tissue from the infected or normal mice were collected. Then 4 groups were set：liver homogenate from infected mice + SNP (Group A), liver homogenate from normal mice + SNP (Group B), peripheral blood from infected mice + SNP (Group C), and peripheral blood from normal mice + SNP (Group D). The final concentrations of SNP in each group were set as 0 (blank control), 2, 5, 10 µmol/L and 30 µmol/L, respectively. After reacting with SNP at 37 ℃ for 30 min, the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) activities, and malondialdehyde (MDA) concentration were examined and compared. RESULTS: The levels of SOD, CAT, GSH-Px and MDA concentration in the liver and the blood from the mice infected with T. spiralis were significantly higher than those of the normal ones (all P < 0.05). When reacted with 10 µmol/L and 30 µmol/L SNP, the SOD, GSH-Px, and CAT activities in Group A and B decreased significantly (all P < 0.05), while the liver MDA concentration reacted with 2-30 µmol/L SNP increased obviously (all P < 0.05). As reacted with 30 µmol/L SNP, the activities of blood SOD, GSH-Px, and CAT in Group C and D decreased, while the MDA concentration in blood still increased (all P < 0.01). When the SNP concentration was in the range of 2-30 µmol/L, there were a negative correlation between the SNP concentrations and SOD, GSH-Px, and CAT activities, as well as a positive correlation with the MDA concentration in the liver and blood from the mice infected with T. spiralis (all P < 0.05). CONCLUSIONS: T. spiralis infection could cause oxidative damage to mice, and increase SOD, GSH-Px, and CAT activities. Nitric oxide released from SNP can decrease antioxidase activities, and inhibit the antioxidant capacity of mice infected with T. spiralis.

Diffuse 18F-FDG Muscle Uptake in Trichinella spiralis Infection.

Two patients were referred to our emergency department with myalgia, fever, general malaise, eosinophilia, and elevated serum levels of creatine kinase and troponin T. 18F-FDG PET/CT scan was performed showing a diffuse and homogenous moderately elevated glucose uptake in all muscle groups. Trichinella spiralis infection was confirmed by a muscle biopsy and detection of trichinella antibodies. The muscle biopsy was taken in the left quadriceps because of equal involvement of the skeletal muscles. The differential diagnosis of diffuse 18F-FDG muscle uptake should include trichinella infection, in particular, in the presence of infectious symptoms, eosinophilia, and biochemical signs of muscle damage.

Atorvastatin and metformin administration modulates experimental Trichinella spiralis infection.

The host-parasite interaction can be altered by the changes in the host environment that may be or may not be in favor of successful invasion by the nematode parasite Trichinella spiralis. Metformin and atorvastatin are applied on a wide scale, to the degree that they could be considered as part of the host biochemical environment that can affect the parasite. Therefore, this study aimed to investigate the impact of alteration of the host's biochemical environment by these commonly used drugs upon the course of T. spiralis infection. Mice were divided into three groups: (1) received atorvastatin, (2) received metformin, and (3) untreated, then after one week, animals were infected with T. spiralis. The treatment continued until the end of the experiment. From each group, small intestines and muscles were removed for histopathological, immunohistochemical, and biochemical analyses as well as total muscle larval counts. We found that the oxidative stress and the expression of vascular endothelial growth factor (VEGF) in the muscles were significantly reduced in both drug-receiving groups, while the total larval counts in muscles were only significantly reduced in atorvastatin-receiving group as compared to the infected control group. Moreover, marked reduction in the inflammatory cellular infiltration, cyclooxygenase-2 (COX-2) expression, and oxidative stress was noted in the small intestines of the treated groups as compared to the infected control group. In conclusion, this study provides many insights into the different biochemical changes in the host that the parasite has to face. Moreover, the anti-inflammatory and anti-angiogenic effects should be taken into consideration when treating infections in patients on therapy with atorvastatin or metformin.