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.

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.

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.

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.

Remodeling of hepatic vascular changes after specific chemotherapy of schistosomal periportal fibrosis

Hepatosplenic schistosomiasis was the first human disease in which the possibility of extensive long standing hepatic fibrosis being degraded and removed has been demonstrated. When such changes occurred, the main signs of portal hypertension (splenomegaly, esophageal varices) progressively disappeared, implying that a profound vascular remodeling was concomitantly occurring. Hepatic vascular alterations associated with advanced schistosomiasis have already been investigated. Obstruction of the intrahepatic portal vein branches, plus marked angiogenesis and compensatory hyperplasia and hypertrophy of the arterial tree are the main changes present. However, there are no data revealing how these vascular changes behave during the process of fibrosis regression. Here the mouse model of pipestem fibrosis was used in an investigation about these vascular alterations during the course of the infection, and also after treatment and cure of the disease. Animals representing the two polar hepatic forms of the infection were included: (1) "isolated granulomas" characterized by isolated periovular granulomas sparsely distributed throughout the hepatica parenchyma; and (2) 'pipestem fibrosis' with periovular granulomas and fibrosis being concentrated within portal spaces, before and after treatment, were studied by means of histological and vascular injection-corrosion techniques. Instances of widespread portal vein obstruction of several types were commonly found in the livers of the untreated animals. These obstructive lesions were soon repaired, and completely disappeared four months following specific treatment of schistosomiasis. Treatment was accomplished by the simultaneous administration of praziquantel and oxamniquine. The most impressive results were revealed by the technique of injection of colored masses into the portal system, followed by corrosion in strong acid. The vascular lesions of non-treated pipestem fibrosis were represented...

Cytokine production associated with periportal fibrosis during chronic schistosomiasis mansoni in humans.

Volunteers living in an area where schistosomiasis mansoni is endemic were subjected to ultrasound examination and classified into groups according to the levels of fibrosis diagnosed, namely, absence of indications of fibrosis (group 0), incipient fibrosis (group 1), and moderate/severe fibrosis (group 2). Peripheral blood mononuclear cells (PBMC) collected from the volunteers were stimulated with soluble antigens from adult schistosomes or from schistosome eggs, and the production of the cytokines gamma interferon, tumor necrosis factor alpha, transforming growth factor beta (TGF-beta), interleukin-4 (IL-4), IL-10, and IL-13 was determined. Potential associations of the level of fibrosis with age, sex, intensity of infection, and cytokine production were investigated between the three groups. Univariate analysis identified associations of age (>50), gender (male), and absence of eggs/g of feces with moderate/severe fibrosis and an association of intensity of infection (>100 eggs) with incipient fibrosis. When cytokine production in PBMC cultures stimulated by soluble egg antigens was categorized as low or high, significant differences in the distribution of IL-13 levels were established between groups 0 and 2. No significant differences were detected between the groups in the cytokines produced by PBMC cultures stimulated with soluble antigens from adult schistosomes. When all variables were tested in multivariate analyses, only IL-13 was strongly associated with fibrosis (odds ratio = 5.8; 95% confidence interval [CI] = 1.1 to 30.5). While high levels of TGF-beta appeared to be associated with protection against fibrosis, the strength of the association was low.

Remodeling of hepatic vascular changes after specific chemotherapy of schistosomal periportal fibrosis.

Hepatosplenic schistosomiasis was the first human disease in which the possibility of extensive long standing hepatic fibrosis being degraded and removed has been demonstrated. When such changes occurred, the main signs of portal hypertension (splenomegaly, esophageal varices) progressively disappeared, implying that a profound vascular remodeling was concomitantly occurring. Hepatic vascular alterations associated with advanced schistosomiasis have already been investigated. Obstruction of the intrahepatic portal vein branches, plus marked angiogenesis and compensatory hyperplasia and hypertrophy of the arterial tree are the main changes present. However, there are no data revealing how these vascular changes behave during the process of fibrosis regression. Here the mouse model of pipestem fibrosis was used in an investigation about these vascular alterations during the course of the infection, and also after treatment and cure of the disease. Animals representing the two polar hepatic forms of the infection were included: (1) "isolated granulomas" characterized by isolated periovular granulomas sparsely distributed throughout the hepatica parenchyma; and (2) 'pipestem fibrosis' with periovular granulomas and fibrosis being concentrated within portal spaces, before and after treatment, were studied by means of histological and vascular injection-corrosion techniques. Instances of widespread portal vein obstruction of several types were commonly found in the livers of the untreated animals. These obstructive lesions were soon repaired, and completely disappeared four months following specific treatment of schistosomiasis. Treatment was accomplished by the simultaneous administration of praziquantel and oxamniquine. The most impressive results were revealed by the technique of injection of colored masses into the portal system, followed by corrosion in strong acid. The vascular lesions of non-treated pipestem fibrosis were represented in the plastic casts by considerable diminution of the fine peripheral portal vein radicles, plus dilatation of periportal collaterals. Four months after treatment, this last picture appeared replaced by tufts of newly interwoven vessels formed along the main portal vein branches, disclosing a strong angiomatoid reparative change. Understanding about the cellular elements at play during fibro-vascular repairing changes of hepatic schistosomiasis represents a matter of considerable scientific and conceptual importance. At present time one may only speculate about the participation of some type of natural stem-cell capable of restoring the diseased liver back to normal once the cause of the disorder has been eliminated.

Characterization of the murine model of schistosomal hepatic periportal fibrosis ('pipestem' fibrosis).

During mild (one to two pairs of worms) and prolonged (23 weeks or more) mouse infections with Schistosoma mansoni, but not with S. japonicum, periovular granulomas and fibrosis were seen to be preferentially located along periportal tissues. This caused fibrotic expansion of the portal spaces on a background of normal-looking hepatic parenchyma, a picture mimicking 'clay pipestem fibrosis' seen in human patients with advanced schistosomiasis. The model was reproduced in outbred and in several strains of inbred mice, and their main characteristics were studied and compared to the human counterpart. A balanced consideration of the similarities and differences between the murine model and human pipestem fibrosis is needed for the adequate utilization of this simple, reproducible and inexpensive experimental model.

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

Oito grupos de camundongos albinos (Mus musculus), näo isogênicos, foram infectados transcutaneamente com cerca de 450 cercárias (das cepas LE e SJ do S. mansoni), irradiadas com 3 Krad, 20 Krad e 40 Krad de radiaçäo gama proveniente de cobalto-60, e näo irradiados (grupos-controle). Os vermes provenientes de carcárias irradiadas com 20 e 40 Krad só foram encontrados em quantidades insignificantes no sistema porta. Verificou-se que os vermes irradiados com 3 Krad, que alcançam o sistema porta, mostram nítido retardo no desenvolvimento evolutivo quando comparados com os grupos-controles näo irradiados. Os vermes da cepa SJ (irradiados ou näo) têm evoluçäo mais lenta do que os da cepa LE

[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.

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

Foi estudada a migraçäo do Schistosoma mansoni (cepas LE e SJ) em oito grupos de camundongos albinos (Mus musculus) näo isogênicos, infectados transcutaneamente com cerca de 450 cercárias näo irradiadas (grupos controles e irradiadas com 3 Krad, e 40 Krad de radiaçäo gama proveniente de cobalto-60. Na pele, observou-se uma diminuiçäo progressiva das taxas de recuperaçäo em funçäo do tempo e, nos pulmöes e sistema porta, verificou-se uma relaçäo inversa significativa entre as taxas de recuperaçäo total e as doses de irradiaçäo. A dose de 20 Krad praticamente impede a migraçäo dos parasitos, de ambas as cepas, dos pulmöes até o sistema porta, enquanto a de 40 Krd praticamente impede a migraçäo dos mesmos da pele para os pulmöes

[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.