Therapeutic Potential of Bone Marrow-Derived Mesenchymal Stem Cells on Experimental Liver Injury Induced by Schistosoma mansoni: A Histological Study

BACKGROUND AND OBJECTIVES: Bone marrow derived mesenchymal stem cells (BM-MSCs) have been proposed as effective treatment of many diseases owing to their unique ability to differentiate into other cell types in vivo. Schistosoma mansoni (S. mansoni) infection is characterized by hepatic granuloma formation around schistosome eggs at acute stage of infection, followed by hepatic fibrosis at chronic and advanced stages. Whether BM-MSCs have an ameliorative effect on hepatic tissue injury caused by S. mansoni infection or not, was inspected in the current study. MATERIALS AND RESULTS: Female Swiss Albino mice were divided into a control group and an experimental group. Half of control animals served as donors for bone marrow stem cells, and the other half was used to collect liver samples. Experimental group was injected with circariae of S. mansoni, and then subdivided into three subgroups; Subgroup B1, sacrificed after eight weeks of infection without treatment, subgroup B2, received BM-MSCs at the eighth week and sacrificed four weeks later, and subgroup B3, was untreated till the twelfth week of infection. Histological examination of liver samples showed the formation of granulomas and liver fibrosis which were extensive in subgroup B3. However, treated subgroup illustrated improvement of liver histology, signs of hepatocytes regeneration, and possible contribution of oval cell in the process of hepatic and biliary regeneration. CONCLUSION: BM-MSCs decreased liver fibrosis and contributed to an increase in oval cells, generation of new hepatocytes and/or to the improvement of resident hepatocytes in S. mansoni infected mice.

El factor de crecimiento del endotelio vascular hepático en la infección murina por Schistosoma mansoni / The endothelial growth factor vascular infection in murine liver by Schistosoma mansoni

Los antígenos secretados por los huevos de S. mansoni inducen la proliferación de células endoteliales in vivo, así como la producción del Factor de Crecimiento del Endotelio Vascular (VEGF), sugiriendo que la patogénesis en la esquistosomiasis se relaciona con eventos angiogénicos. Se evaluó la expresión del VEGF, como una medida de angiogénesis estimulada por los huevos y los gusanos de S. mansoni, en la infección Bisexual (BIS) y los gusanos adulto (infección UNI) en el hígado de ratones Balb/c, antes y después del tratamiento con PZQ. Los resultados indican que tanto la infección UNI como BIS son capaces de estimular la producción de VEGF en tejido hepático, lo que explica la vascularizacón anómala durante este cuadro infeccioso. Este proceso se acompaña con la presencia de un elevado número de infiltrados leucocitarios en los sitios donde se observa lesión tisular; la producción de VEFG remite tras 48 de tratamiento con PZQ. Estos resultados indican que la producción anómala de VEGF junto con la intensa respuesta pro-inflamatoria asociada no solo a la actividad de VEGF sino también a los infiltrados leucocitarios observados en el tejido hepático, causada tanto por los huevos secretados como por las formas adultas de S. mansoni son los mecanismos que subyacen a las lesiones granulomatosas observadas durante el curso de la esquistosomiasis, pudiendo al menos revertirse el incremento en la vascularización mediante el uso de PZQ.

The antigens secreted by eggs of S. mansoni induce the proliferation of endothelial cells in vivo, as well as the production of Factor Vascular Endothelial Growth factor (VEGF), suggesting that the pathogenesis of schistosomiasis relations with angiogenic events. We evaluated the expression of VEGF, as a measure of angiogenesis stimulated by the eggs and worms S. mansoni in infection bisexual (BIS) and adult worms ( UNI infection ) in the liver of BALB / c mice before and after treatment with PZQ. These results indicate that abnormal production of VEGF with intense pro-inflammatory response not only associated with the activity of VEGF but also leukocyte infiltrates observed in the liver tissue caused by both secreted and eggs by adult forms S. mansoni are the mechanisms underlying granulomatous lesions observed during the course of schistosomiasis, and can be reversed at least the increased vascularization by using PZQ .

Two sequential PCR amplifications for detection of Schistosoma mansoni in stool samples with low parasite load / Duas amplificações sequenciais por PCR para detecção de Schistosoma mansoni em amostras de fezes com baixa carga parasitária

Schistosomiasis constitutes a major public health problem, with an estimated 200 million individuals infected worldwide and 700 million people living in risk areas. In Brazil there are areas of high, medium and low endemicity. Studies have shown that in endemic areas with a low prevalence of Schistosoma infection the sensitivity of parasitological methods is clearly reduced. Consequently diagnosis is often impeded due to the presence of false-negative results. The aim of this study is to present the PCR reamplification (Re-PCR) protocol for the detection of Schistosoma mansoni in samples with low parasite load (with less than 100 eggs per gram (epg) of feces). Three methods were used for the lysis of the envelopes of the S. mansoni eggs and two techniques of DNA extraction were carried out. Extracted DNA was quantified, and the results suggested that the extraction technique, which mixed glass beads with a guanidine isothiocyanate/phenol/chloroform (GT) solution, produced good results. PCR reamplification was conducted and detection sensitivity was found to be five eggs per 500 mg of artificially marked feces. The results achieved using these methods suggest that they are potentially viable for the detection of Schistosoma infection with low parasite load.

A esquistossomose constitui grande problema de saúde pública, sendo que estimativas apontam para 200 milhões de pessoas infectadas no mundo e 700 milhões de pessoas em áreas de risco. No Brasil, existem áreas de alta, média e baixa endemicidade. Estudos demonstram que nas áreas endêmicas de baixa prevalência da infecção, a reduzida sensibilidade dos métodos parasitológicos torna-se evidente. Isto dificulta o diagnóstico, pela presença de resultados falso-negativos. O objetivo deste estudo foi a padronização de um protocolo de reamplificação da PCR (Re-PCR) para a detecção de Schistosoma mansoni em amostras com menos de 100 ovos por grama (opg) de fezes. Foram utilizados três métodos para ruptura dos envoltórios dos ovos de S. mansoni e duas técnicas de extração de DNA foram aplicadas. O DNA extraído foi quantificado e os resultados sugerem que a técnica de extração de melhor produtividade foi a que associa esferas de vidro a uma solução de isotiocianato de guanidina/fenol/clorofórmio (GT). Aplicou-se a Re-PCR, que demonstrou sensibilidade para a detecção de cinco ovos/500 mg de fezes artificialmente marcadas. Assim, essas novas ferramentas são potencialmente aplicáveis nas infecções por S. mansoni com baixa carga parasitária.

Schistosoma mansoni antigens alter the cytokine response in vitro during cutaneous leishmaniasis

Schistosoma mansoni infection or associated products are able to down-modulate the type 1 CD4+ T cell inflammatory response characteristic of autoimmune diseases. In this study, we evaluated how S. mansoni antigens altered the immune response that was induced by the soluble Leishmania antigen (SLA) from cutaneous leishmaniasis (CL) patients. Cytokines were measured from the supernatants of peripheral blood mononuclear cell cultures stimulated with SLA. This was performed using the sandwich enzyme linked immunosorbent assay technique in the presence or absence of S. mansoni recombinant antigens Sm29, SmTSP-2 and PIII. The addition of S. mansoni antigens to the cultures resulted in the reduction of interferon gamma (IFN-γ) levels in 37-50 percent of patients. Although to a lesser extent, the antigens were also able to decrease the production of tumour necrosis factor-alpha (TNF-α). We compared patients that either had or did not have reduction in IFN-γ and TNF-α production in cultures stimulated with SLA in the presence of S. mansoni antigens. We found that there was no significant difference in the levels of interleukin (IL)-10 and IL-5 in response to S. mansoni antigens between the groups. The antigens used in this study down-modulated the in vitro proinflammatory response induced by SLA in a group of CL patients through a currently undefined mechanism.

Genital schistosomiasis mansoni concomitant to genital tumor in areas of low endemicity: challenging diagnosis

Genital infection by Schistosoma mansoni is usually misdiagnosed in individuals who reside in, or travel to endemic areas. We describe two cases of genital tumor associated with S. mansoni infection manifested by methrorragy. Surgical specimens revealed leiomyomas in both cases associated with S. mansoni. In one of them, granulomas were found in the ovary and in the other they were found in the uterine tube. Although none presented intestinal/hepatic disease, fecal egg excretion was detected in one. Both had elevated pretreatment antibody reactivity to S. mansoni antigen, but follow-up showed different outcomes. Schistosomiasis should be considered as a diagnosis in individuals with methrorragy residing in or having traveled to endemic areas. Since diagnosis follows genital amputation, and cure control is troublesome, improvement of diagnostic tools and follow-up markers are important priorities to decrease schistosomiasis morbidity.

Schistosoma mansoni: a rare cause of tubal infection

S. haematobium is an important cause of urinary schistosomiasis, and symptomatic female genital infection is a common gynecological finding in areas where S. haematobium is prevalent. On the other hand, genital manifestations of intestinal schistosomas as S. mansoni are not frequent or are misdiagnosed. A case of a 40-year-old woman with abnormal uterine bleeding and asymptomatic tubal infection by S. mansoni identified in histological examination is presented.

Efetividade do Programa de Comunicação e Educação em Saúde no controle da infecção por S. mansoni em algumas areas do Estado da Bahia / The effectiveness of the Program of Communication and Education in Health on the control of S. mansoni infection in some areas of the state of Bahia

O Programa de Controle da Esquistossomose (PCE) vem sendo desenvolvido em áreas da Bahia pela Fundação Nacional de Saúde (FNS). Em 1989, ações de Informação, Educação, Comunicação e Mobilização Comunitária (IEC/MC) foram iniciadas. Neste estudo avalia-se o impacto epidemiológico do IEC/MC, adotando-se um desenho quasi-experimental, comparando-se prevalências de infecção por S. mansoni em áreas IEC/MC com estimativas de áreas referentes. Os dados são secundários, coletados rotineiramente pela FNS. Verificou-se uma redução da prevalência da esquistossomose em todas as áreas, que alcança maior intensidade nas áreas com IEC/MC. Aparentemente, ações de controle rotineiras realizadas isoladamente são mais efetivas entre escolares e pessoas do sexo masculino, enquanto que nas áreas com IEC/MC, observou-se maior impacto entre as mulheres, refletindo, provavelmente, as distintas estratégias adotadas. Aponta-se para a necessidade de estudos de avaliação qualitativos, além de estimativas do custo-benefício e custo-efetividade de modo a aprimorar o processo de tomada de decisões.

The Program for S. mansoni Control (PCE) has been developed in some areas of the State of Bahia by the Fundação Nacional de Saúde (FNS). In 1989, activities on Information, Education, Communication and Community Mobilization (IEC/MC) were initiated. This study evaluates the epidemiological impact of the IEC/MC, using a quasi-experimental study design strategy, comparing the prevalences of infection for S. mansoni in areas of IEC/MC and estimates of other areas. The data used were routinely collected by the local staff of the FNS. A decrease on the prevalence of S. mansoni infection was found in all study areas, specially in those of IEC/MC activities. Findings indicate that PCE activities are more effective among school-age individuals and male adults, although IEC/MC allows for higher epidemiological impact among women, reflecting the differences among the strategies. These findings point out the need for qualitative evaluation research, as well as cost benefit and cost effectiveness analyses, that are more appropriate for decision making processes.

Studies on resistance of Schistosoma to praziquantel Ⅺ Experimental investigation on susceptibility of field isolates of Schistosoma japonicum in stages of eggs,miracidia and cercariae to praziquantel / 中国血吸虫病防治杂志

Objective To establish a test in vitro to monitor the susceptibility of field isolates of Schistosoma japonicum in stages of eggs,miracidia and cercariae to praziquantel.Methods Six iso-lates of S.japonicum were collected from the endemic regions in Hunan,Hubei,Jiangxi,Anhui,Jiangsu and Yunan provinces,China and 3 isolates of S.mansoni established in the lab were as the control.The eggs were incubated in 5?10-6,10-6,5?10-7,10-7mol/L praziquantel for 24 hours,then the eggs were transferred to fresh water to hatch miracidia and the hatch rates were investigated and compared.The miracidia were exposed to 5?10-6,10-6,5?10-7,10-7mol/L praziquantel for 0,1 and 5 min and then the swimming behavior and morphological changes were observed.The cercariae were exposed in 10-5,6?10-7,4?10-7,10-7 mol/L praziquantel for 0,20,40,60,80,100 min and then the changes in the patterns of behavior,including swimming,contraction and tail shedding were observed under a dissecting microscope.The number of cercariae which had shed tails were counted.The differences between S.japonicum and S.mansoni were compared.Results Following the incubation in 10-6,5?10-7,10-7 mol/L praziquantel solutions for 24 h,the hatching rates of the eggs of S.japonicum were 0.52%,11.90% and 49.15%,respectively,while the hatching rates of the eggs of S.mansoni which were 4.17%,31.37% and 92.53%.When the miracidia were exposed to 10-6 mol/L praziquante for 1 min,100% of miracidia from S.japonicum changed their shape,while only 55.73% of miracidia from S.mansoni isolates changed their shape.When the miracidia were exposed to 5?10-7,10-7mol/L praziquantel,respectively,for 5 min,96.75% and 37.57% of miracidia from S.japonicum changed their shapes while only 21.80% and 0 of miracidia from S.mansoni isolates changed their shapes.When the cercariae were exposed to 10-5 mol/L praziquantel over 40 min,96.75% of the cercariae from S.japonicum isolates shed their tails,while only 28.30% of the cercariae from S.mansoni isolates shed their tails.When the cercariae were exposed to 4?10-7 mol/L praziquantel over 100 min,95.82% of the cercariae from S.japonicum isolates shed their tails,while only 11.40% of the cercariae from S.mansoni isolates shed their tails.When the cercariae were exposed to 10-7 mol/L praziquantel over 80 min,29.65% of the cercariae from S.japonicum isolates shed their tails,while no cercariae from S.mansoni isolates shed the tails.Conclusions There were no difference in responses to praziquantel at the egg,miracidial and cercarial stages among S.japonicum isolates,but the in vitro responses to praziquantel of eggs,miracidia and cercariae of S.japonicum compared with S.mansoni demonstrate that eggs,miracidia and cercariae of S.japonicum are more sensitive to praziquantel than those of S.mansoni.The percentage of the changes in the shape of miracidia from S.japonicum isolates following the exposure to 5?10-7mol/L praziquantel for 1 minute may be used to determine whether the failed therapy in patients infected with S.japonicum is due to the presence of praziquantel unsusceptible worms.The tail shedding rates of cercariae of following the exposure to 4?10-7 mol/L praziquantel for 80-100 minutes could be used to monitor for the presence of praziquantel-resistant worms in infected snails collected from the field.