Long-term ethanol intake causes morphological changes in Schistosoma mansoni adult worms in mice.

Schistosoma mansoni adult worms are extensively challenged by reactive oxygen species from intrinsic sources. However, the effects of extrinsic sources such as ethanol have not been looked at in schistosomes. We examined adult worms recovered from ethanol-consuming mice by light (LM), confocal (CM) and scanning electron microscopy (SEM) to address this question. Schistosomiasis-infected mice were orally gavaged with 18% (v/v) ethanol from 35 to 63 days post-infection, when they were euthanized. CM examination revealed reduced germ cells density (-36%, p = 0.0001) and sperm density (-58%, p = 0.0001) in testicular lobes, and immature cells in seminal vesicle compared to unexposed control worms. Female worms showed reduced density of vitellin glands (-71%, p = 0.0001), maturation of oocytes (-7%, p = 0.0071) and reduced spermatozoa density (-23%, p = 0.0002) within the seminal receptacle. SEM revealed remarkable damages in male's tegument, including tubercles flattening, tegumental peeling and erosive lesions. Given that lipids are present in reproductive system and tegument, our results suggest that phenotypic changes are due to ethanol-induced lipid peroxidation. To the best of our knowledge, this is the first report revealing the biological action of ethanol intake on adult schistosomes in vivo.

Phenotypic plasticity of male Schistosoma mansoni from the peritoneal cavity and hepatic portal system of laboratory mice and hamsters.

Morphometric analysis of Schistosoma mansoni male worms obtained from AKR/J and Swiss mice was carried out. Rodents infected by the intraperitoneal route with 80 cercariae of the schistosome (LE strain) were killed by cervical dislocation at 45 and 60 days post-infection and both peritoneal lavage and perfusion of the portal system were performed for the recovery of adult worms. Characteristics including total body length, the distance between oral and ventral suckers, extension of testicular mass and the number of testes were considered in the morphological analysis. Changes that occurred in S. mansoni recovered from the peritoneal cavity or from the portal system of AKR/J and Swiss mice included total body length and reproductive characteristics. Significant morphometric alterations were also observed when worms recovered from the portal system of both strains of mice were compared with the schistosomes obtained from hamsters (Mesocricetus auratus), the vertebrate host in which the LE strain had been adapted and maintained by successive passages for more than four decades. The present results reinforce the idea that S. mansoni has high plastic potential and adaptive capacity.

Propolis enhances the effectiveness of praziquantel in experimental schistosomiasis: biochemical and histopathological study.

Despite the wide current use of praziquantel (PZQ) in treatment of schistosomiasis, low cure rates have been recorded in many studies. The aim of this study was directed to evaluate the curative effect of propolis (Pps) alone or in combination with PZQ on biochemical, immunological, parasitological, and histological changes associated with experimental schistosomiasis in mice. Schistosoma mansoni-infected mice were divided into two experimental sets, each with four subgroups: (i) untreated, (ii) treated with Pps/day p.o for 4 weeks, (iii) treated with PZQ p.o 2 × 500 mg/kg bd wt, and (iv) treated with Pps + PZQ as in group ii and iii; all treatments started on the 8th week postinfection, in addition to uninfected group as control for the previous groups. Treatment of infected mice with Pps, although failed to eradicate the worm, significantly reduced the hepatic granuloma number, their lymphocytic infiltration and aggregation, hepatic and splenic myeloperoxidase (MPO) activity and plasma, and liver and thymus nitric oxide (NOx) levels together with normalization of plasma proteins and alleviation of oxidative stress in the examined tissues as evidenced by reduction of malondialdehyde (MDA) and normalization of glutathione (GSH). Promising results were obtained when Pps was given in combination with PZQ, where the anti-schistosomal activity of PZQ was markedly potentiated with complete alleviation and amelioration of the histological and biochemical alteration associated with schistosomiasis. This study highlights the potential usefulness of Pps as an adjunct to PZQ in schistosomiasis.

Interobserver variability of ultrasound parameters in portal hypertension.

The aim of this study was to assess interobserver agreement of ultrasound parameters for portal hypertension in hepatosplenic mansonic schistosomiasis. Spleen size, diameter of the portal, splenic and superior mesenteric veins and presence of thrombosis and cavernous transformation were determined by three radiologists in blinded and independent fashion in 30 patients. Interobserver agreement was measured by the kappa index and intraclass correlation coefficient. Interobserver agreement was considered substantial (kappa = 0.714-0.795) for portal vein thrombosis and perfect (kappa = 1) for cavernous transformation. Interobserver agreement measured by the intraclass correlation coefficient was excellent for longitudinal diameter of the spleen (r = 0.828-0.869) and splenic index (r = 0.816-0.905) and varied from fair to almost perfect for diameter of the portal (r = 0.622-0.675), splenic (r = 0.573-0.913) and superior mesenteric (r = 0.525-0.607) veins. According to the results, ultrasound is a highly reproducible method for the main morphological parameters of portal hypertension in schistosomiasis patients.

Effects of pentoxifylline during Schistosoma mansoni infection in Swiss mice: an analysis of worm burden, fecundity and liver histopathology.

The short-term effects of pentoxifylline (PTX) on granulomatous lesions during Schistosoma mansoni infection in Swiss mice were evaluated. Drug administration was initiated 42 and 140 days post-infection (DPI) for the acute and chronic infection groups, respectively. Treatment was carried out daily with 200 mg/kg (subcutaneous route) of the drug for five consecutive days. Recovery of parasites and tissues was performed at 49 DPI and 147 DPI, respectively. Liver histological analysis showed a decrease in the inflammatory reaction and fibrous content of the granulomas studied, and a significant reduction (P < 0.001) in their mean diameter was observed in the groups of rodents treated with PTX in acute and chronic infection, when compared to their respective control groups. However, no alteration in the number of S. mansoni recovered from the portal system was observed, and egg-laying kinetics was not notably modified by PTX treatment, and the immature stage distribution of S. mansoni eggs showed minor intrinsic variations with no statistical differences in the parameter second-stage/female/g among untreated mice and treated mice in acute and chronic infections, respectively, when evaluated by intestinal oograms. Data obtained indicate probable immunomodulatory effects of PTX in murine schistosomiasis both in acute and chronic infection.

Host susceptibility to schistosomes: effect of host sera on cell proliferation of Schistosoma mansoni schistosomula.

To determine effects of the sera on cell proliferation, schistosomula of Schistosoma mansoni (20-days-old) were incubated in medium containing fetal calf serum plus hamster (highly susceptible host) portal or peripheral venous serum, or rat (poorly susceptible host) portal or peripheral venous serum in the presence of bromodeoxyuridine (BrdU). Compared with schistosomula cultured in presence of control medium containing fetal calf serum alone, BrdU labeling indices (BLIs) were increased by 39% in the presence of portal, but not in peripheral, serum of hamsters. In contrast, no significant differences were observed in the BLIs in rat portal, or peripheral, sera or in control media. In vivo BrdU labeling results revealed that there was no detectable cell proliferation in S. mansoni schistosomula (6 days old) in the lungs. However, cell proliferation was detected in schistosomula beginning at 17 days. The results indicated that portal venous serum from a highly susceptible host, but not from a poorly susceptible host, stimulated schistosome cell proliferation in vitro. The timing of the increase in cell proliferation in terms of development corresponded to liver portal-mesenteric localization of schistosomula. Together, the data support the conclusion that in susceptible hosts, portal serum may play a role in schistosome cell proliferation, possibly resulting in termination of schistosome migration. This may explain the colocalization of adults, and the known organ selectivity of disease.

Protective effects of hydrogen sulfide on portal hypertensive vasculopathy in rabbits by activating AKT-NF-κB pathway.

The role of hydrogen sulfide (H2S) in portal hypertension (PH)-induced esophagus-gastric junction vascular lesions in rabbits was observed. The rabbit PH models were established. The animals were randomly divided into the following groups: normal, PH, PH+sodium hydrosulfide (PH+S), PH+propargylglycine (PH+PPG). The plasma H2S levels, apoptosis of esophageal-gastric junction vascular smooth muscle cells, and the expression of nuclear transcription factor-κB (NF-κB), p-AKT, IκBa and Bcl-2 were detected. The cystathionine γ lyase (cystathionine-gamma-splitting enzyme, CSE) in the junction vascular tissue was measured. The results showed that the plasma H2S levels and the CSE expression levels had statistically significant difference among different groups (P<0.05). As compared with PH group, plasma H2S levels were declined obviously (11.9±4.2 vs. 20.6±4.5, P<0.05), and CSE expression levels in the junction vascular tissue were notably reduced (1.7±0.6 vs. 2.8±0.8, P<0.05), apoptosis rate of vascular smooth muscle cells per unit area was significantly decreased (0.10±0.15 vs. 0.24±0.07, P<0.05), and the expression levels of p-AKT and NF-κB were significantly decreased (2.31±0.33 vs. 3.04±0.38, P<0.05; 0.33±0.17 vs. 0.51±0.23, P<0.05), however, IκBa and Bcl-2 expression increased obviously (5.57±0.17 vs. 3.67±0.13, P<0.05; 0.79±0.29 vs. 0.44±0.36, P<0.05) in PH+PPG group. As compared with PH group, H2S levels were notably increased (32.7±7.3 vs. 20.6±4.5, P<0.05), the CSE levels in the junction vascular tissue were significantly increased (6.3±0.7 vs. 2.8±0.8, P<0.05), apoptosis rate of vascular smooth muscle cells per unit area was significantly increased (0.35±0.14 vs. 0.24±0.07, P<0.05), and the expression levels of p-AKT and NF-κB were significantly increased (4.29±0.49 vs. 3.04±0.38, P<0.05; 0.77±0.27 vs. 0.51±0.23, P<0.05), yet IκBa and Bcl-2 expression decreased significantly (3.23±0.24 vs. 3.67±0.13, P<0.05; 0.31±0.23 vs. 0.48±0.34, P<0.05) in PH+S group. It is concluded that esophagus-gastric junction vascular lesions happen under PH, and apoptosis of smooth muscle cells is declined. H2S can activate NF-κB by the p-AKT pathway, leading to the down-regulation of Bcl-2, eventually stimulating apoptosis of vascular smooth muscle cells, easing PH. H2S/CSE system may play an important role in remission of PH via the AKT-NF-κB pathway.

Evaluation of the cytokine mannose-binding lectin as a mediator of periportal fibrosis progression in patients with schistosomiasis.

INTRODUCTION: We hypothesized higher mannose-binding lectin level and classic factors (i.e., age, sex, alcohol consumption, exposure, and specific treatment) are associated with the severity of periportal fibrosis in schistosomiasis. METHODS: This cross-sectional study involved 79 patients infected with Schistosoma mansoni with severe or mild/moderate periportal fibrosis. Serum concentrations of mannose-binding lectin were obtained by enzyme-linked immunosorbent assay (ELISA). RESULTS: Higher serum level of mannose-binding lectin was significantly associated with advanced periportal fibrosis. CONCLUSIONS: Mannose-binding lectin may contribute to liver pathology in schistosomiasis and may represent a risk factor for advanced periportal fibrosis in the Brazilian population studied.

Effects of protective immune serum on the yields of parasites and pulmonary cell reactions in schistosome-infected rats.

Yields of parasites during the period of worm migration from the lungs to the portal circulation were measured in S. mansoni-infected Fischer rats passively immunized with protective serum from twice-infected donor rats. Two effects of protective serum were observed in recipient rats relative to normal serum recipients: yields of schistosomula from lungs were higher and yields of (immature) worms from the portal circulation were lower throughout the period analyzed. Histopathological analysis of lung tissue confirmed the presence of greater numbers of schistosomula in lungs of passively immunized rats. In addition, the percent of lung schistosomula involved in all categories of inflammatory reactions was greater in recipients of protective rat serum. The kinetics of accumulation of worms perfused from the portal circulation of normal and passively immunized rats indicate that in the latter group a smaller fraction of worms successfully migrates to the portal circulation. These findings support the hypothesis that protective activity of the serum prevents a portion of worms from successfully completing migration from the lung to the portal circulation.

Natural history of Schistosoma mansoni infection in mice: egg production, egg passage in the feces, and contribution of host and parasite death to changes in worm numbers.

Mice, C57Bl/6N (B6) and BALB/cAnN (BALB), infected with Schistosoma mansoni were examined 8-26 weeks postinfection (PI) to estimate the fecundity of the worms and the contribution of death of worms and the death of heavily infected mice to the decrease in worm numbers in chronic infections. Portal worms were recovered by perfusion and the lungs were examined for parasites shunted from the portal circulation. Animals that died were more heavily infected than those that survived. Between eight and 12 weeks PI, this loss of worms resulted in a net decrease of approximately 19% of worm pairs in surviving BALB mice, but of only 4% in B6 mice. Loss of portal worms to the lungs after the eighth week of infection was 9-13% of portal worms in BALB mice and 3-4% in B6 mice. The estimated rates of egg production by S. mansoni decreased slightly with time in both strains of mice. At 12 and 20 weeks PI, tissue eggs per worm pair and eggs passed in the feces per worm pair often decreased as the intensity of infection increased. We do not consider the loss of worms in the murine host relevant to most infections in humans because of the high intensity of infection relative to body size in mice and the high frequency of severe portal obstruction in murine infections.

A fatty acid binding protein from Fasciola hepatica induced protection in C57/BL mice from challenge infection with Schistosoma bovis.

Three strains of mice (NMRI, C57/BL, BALB/c) were each immunized with a 12 kDa purified, native Fasciola hepatica fatty acid binding protein (Fh12) and challenged percutaneously with Schistosoma bovis cercariae. C57/BL mice immunized with Fh12 had significant reductions in S. bovis worm burden recoveries (96 and 87% reductions over controls in two separate experiments). When using NMRI or BALB/c mice, Fh12 alone or in Freund's adjuvant failed to induce significant protection against S. bovis. In C57/BL mice vaccinated against Fh 12, antibodies to the IgG2a isotype, but not to the IgG1 isotype, increased by 2 weeks after the second immunization and remained high through 8 weeks of S. bovis infection. Antibodies to S. bovis increased after 4 weeks of infection. Regarding cytokine production by spleen mononuclear cells, C57/BL mice vaccinated with Fh12 in adjuvant, and having the highest protective response against challenge infection with S. bovis, had an increase of IFN-gamma production with Concanavalin A but no increase of IL-4 in similarly stimulated cells. These results suggest that the protection obtained in this group of mice is mediated by a Th1 immune response.

Schistosoma mansoni: the immune response against cercarial glycocalyx.

Schistosoma mansoni cercarial glycocalyx was separated and purified by Sephacryl-300 SR. It was found to stimulate the humoral immune response in mice injected with it. Antiglycoalyx antibodies raised in CD/1 mice were found to be cytotoxic to schistosomula in vitro. But conversely, no protective effect was demonstrated in vivo. Eosinophil-mediated cytotoxicity was found to have no effector function in the murine immune response against schistosomes. A monoclonal antiglycocalyx IgM was prepared during our study. It was found to have no cytotoxic effect on schistosomules in vitro. However, it was found to have an inhibitory activity blocking the cytotoxic effect of other antiglycocalyx isotypes in the immune mouse. The contradiction between the result of antiglycocalyx antibody-mediated cytotoxicity obtained in vivo and that obtained in vitro is in itself revealing and suggests that the effect is crucially dependent upon factors as yet poorly understood.

Rejection of mouse-derived Schistosoma japonicum and serum lethality of host immunized with mouse globulin or mouse erythrocytes.

Fourteen-day-old, mouse-derived Schistosoma japonicum schistosomula survived, matured, and deposited viable eggs following surgical transfer to the hepatic portal system of rabbits. The survival of such schistosomula is essentially eliminated in rabbits immunized with either mouse erythrocytes or mouse gamma globulin. Sera from rabbits immunized with either mouse erthrocytes or mouse gamma globulin in the presence of normal leukocytes is lethal for mouse-derived schistosomula 14 days of age or older. These sera have no significant effect on newly transformed schistosomula or those derived from rabbits. It is suggested that these results give additional evidence that immunological enhancement is one of the mechanisms involved in parasite survival.

Schistosoma mansoni: mechanism of attrition and routes of migration from lungs to hepatic portal system in the laboratory mouse.

The number of schistosomula in the axillary lymph nodes of mice was determined by compressed tissue autoradiography at 13 intervals from 0.5 to 28 days after exposure of abdominal skin to 75Se-labeled cercariae of S. mansoni. Significant accumulations were observed between days 3 and 6 and peaked on day 4 at which time 9.4 +/- 1.1% of the schistosomula present in the whole body were found in the axillary lymph nodes. The total number and distribution of schistosomula in all tissues of mice were likewise determined at 12 intervals from 3 to 24 days following exposure. The frequent appearance of small numbers of schistosomula in trachea and esophagus suggested that normal attrition resulted at least in part from physical expulsion of schistosomula from the body by way of the tracheobronchial tree and gastrointestinal tract. The distribution of schistosomula observed in heart chambers, caudal vena cava, hepatic portal vein, aorta, intestinal wall, thoracic cavity rinses, and diaphragm supported all 3 standing hypotheses regarding route of migration from lungs to hepatic portal system, i.e., that schistosomula migrate via (1) the pulmonary artery, right heart, caudal vena cava, and hepatic veins, (2) the pulmonary vein, left heart, aorta, and cranial mesenteric artery, and (3) the thoracic cavity and diaphragm.

[Schistosoma mansoni: quantitative aspects of the development of irradiated cercariae in the skin, lungs and portal system, in mice]. / Schistosoma mansoni: aspectos quantitativos da evolução de cercárias irradiadas a nível da pele, pulmões e sistema porta, em camundongos.

The migration of Schistosoma mansoni (LE and SJ strains) has been studied in eight groups of outbred Swiss albino mice (Mus musculus), which were previously infected with ca 450 cercariae, transcutaneously. The infection of mice was performed with non irradiated cercariae (control groups), or with gamma-irradiated cercariae, at the schedule of 3, 20 and 40 Krad. Regarding the skin, a progressive decrease was detected for the recovery rates, related to the time of infection. As far as the lungs and portal system are concerned, a significant inverse correlation was observed between the total recovery rate and the irradiation dosages. The dose of 20 Krad practically hinders the migration of the parasites (in both strains) from the lungs to the portal system, whereas the dose of 40 Krad prevents the migration of most of the parasites from the skin to the lungs.

Asexually proliferous tetrathyridia of Mesocestoides sp. in the hepatic portal system of the prairie rattlesnake (Crotalus viridis viridis).

A female prairie rattlesnake (Crotalus viridis viridis) was gastric intubated with 250 tetrathyridia of Mesocestoides sp. The snake was killed 12 wk postinfection; a portion of the liver was examined histologically for evidence of tetrathyridia. Five tetrathyridia were seen in two hepatic portal triad vessels. We propose that a blood-borne metastasis of tetrathyridia in reptiles and rodents may occur.

Schistosoma mansoni: relocation of parasites to lungs from hepatic portal system in rodents.

The prevalence and development of adult worms in the lungs of mice and gerbils infected with Schistosoma mansoni was investigated. All infected BALB/c mice harbored the schistosomes in their lungs at 10-12 weeks post-infection, showing the distinct relocation of adult worms to the lungs, from the hepatic portal system. The male and female flukes from lungs of BALB/c mice were significantly smaller than those from livers. The percentage of gravid females in lungs was considerably lower than that in the livers. The number of eggs recovered from lungs of BALB/c mice and gerbils having lung female worms, however, was higher than that from animals without lung females, indicating egg deposition of lung females. The number of eggs detected in the brains correlated well with the number of eggs from the lungs in BALB/c and ICR mice. Out of 119 infected gerbils at 8 weeks post-infection, only two animals had egg-emboli in the brain vessels, although many eggs embolized in the lungs of those animals. These data suggest that transfer of worms to the lungs from livers involves reduction of worm recovery from the portal circulation, and also pulmonary pathology of the disease.

[Schistosoma mansoni: development of worms from cercaria irradiated at the porta system level, in mice]. / Schistosoma mansoni: evolução de vermes oriundos de cercárias irradiadas a nível de sistema porta, no camundongo.

Eight groups of outbred albino mice were infected transcutaneously with cercariae of S. mansoni (strains LE and SJ) irradiated with either 3, 20 or 40 Krad, of gamma radiation from a cobalt-60 bomb and a control non irradiated group. Cercariae irradiated with 20 or 40 Krad failed to develop in the portal system and 3 Krad retarded development. Worms of the SJ strain developed more slowly than the LE strain.

[Periportal fibrosis in Schistosoma mansoni schistosomiasis. An ultrasonographic study in the area of Nkolbisson (Cameroon)]. / Fibrose périportale dans la schistosomiase à Schistosoma mansoni. Une étude ultrasonographique dans le foyer de Nkolbisson (Cameroun).

PURPOSE: The appearance of Symmers' periportal fibrosis (SPF) is considered a major event in the natural history of Schistosoma mansoni infection, because of the risk of portal hypertension and subsequent intestinal hemorrhage. Ultrasonography has been found useful in the assessment of this lesion. We undertook the present study to determine the prevalence of SPF in Nkolbisson (near Yaoundé), where previous studies had shown Schistosoma mansoni infection to be endemic. METHODS AND MATERIALS: 147 patients more than 15 years old (mean age: 32 years) were prospectively studied during a 3 month period. 107 subjects (51 male, and 56 female) were excreting Schistosoma mansoni eggs in the stools (mean egg output = 336 egg/g), and 40 controls had a negative stool exam. A medical history, a physical examination, and an abdominal ultrasound examination were performed on each subject. The degree of SPF was graded according to Homeida's scale. RESULTS: 39 Subjects (24 male, 15 female) with positive stool examination had SPF giving a prevalence rate of 37%, while it was found to be 5% for controls. 28 patients had mild fibrosis (grade I), 7 patients had moderate fibrosis (grade II), and 4 patients had severe fibrosis (grade III). Higher prevalence rates of SPF were associated with longer duration of infection and very high egg outputs (> 1,000 egg/g). The positive predictive value of hepatomegaly or splenomegaly for the presence of SPF was 0.52, and the negative predictive value 0.69. CONCLUSION: We conclude that SPF affects a significant proportion of infected patients and ultrasonography is a valuable tool in the study of this lesion in our patients.

[Studies on fractionation and protective immunity of the membrane antigen from hepato-portal juveniles of Schistosoma japonicum].

OBJECTIVE: To explore the immunological characteristics of the membrane antigen from hepato-portal juveniles of Schistosoma japonicum and its protective immunity against S. japonicum (Sj) in mice. METHODS: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) and enzyme-linked immune electro-transfer blot(EITB) methods were used to recognize the membrane antigens from hepato-portal schistosomula (SjHmAg) by infected rabbit sera (IRS) and normal rabbit sera (NRS). Kunming mice were immunized subcutaneously three times(0, 2, 4 weeks) with SjHmAg. Each mouse was challenged with 40 +/- 1 cercariae. Six weeks later the mice were killed, worms and liver eggs were counted. RESULTS: 7 major protein bands appeared on SDS-PAGE. IRS mainly reacted specifically with SjHmAg of 23, 33 and 63 kDa. Compared with the control groups, the reduction rate of worms and eggs per gram liver in the experimental group were 16.2% and 54.4%, respectively. CONCLUSION: Different protein components from SjHmAg are obtained using SDS-PAGE, and the antigen can induce a protective immunity against Sj in mice.