Schistosoma haematobium infection is associated with alterations in energy and purine-related metabolism in preschool-aged children.

Helminths are parasitic worms that infect over a billion people worldwide. The pathological consequences from infection are due in part, to parasite-induced changes in host metabolic pathways. Here, we analyse the changes in host metabolic profiles, in response to the first Schistosoma haematobium infection and treatment in Zimbabwean children. A cohort of 83 schistosome-negative children (2-5 years old) as determined by parasitological examination, guardian interviews and examination of medical records, was recruited at baseline. Children were followed up after three months for parasitological diagnosis of their first S. haematobium infection, by detection of parasite eggs excreted in urine. Children positive for infection were treated with the antihelminthic drug praziquantel, and treatment efficacy checked three months after treatment. Blood samples were taken at each time point, and capillary electrophoresis mass spectrometry in conjunction with multivariate analysis were used to compare the change in serum metabolite profiles in schistosome-infected versus uninfected children. Following baseline at the three-month follow up, 11 children had become infected with S. haematobium (incidence = 13.3%). Our results showed that infection with S. haematobium was associated with significant increases (>2-fold) in discriminatory metabolites, linked primarily with energy (G6P, 3-PG, AMP, ADP) and purine (AMP, ADP) metabolism. These observed changes were commensurate with schistosome infection intensity, and levels of the affected metabolites were reduced following treatment, albeit not significantly. This study demonstrates that early infection with S. haematobium is associated with alterations in host energy and purine metabolism. Taken together, these changes are consistent with parasite-related clinical manifestations of malnutrition, poor growth and poor physical and cognitive performance observed in schistosome-infected children.

Inhibition of the Formation In Vitro of Putatively Carcinogenic Metabolites Derived from S. haematobium and O. viverrini by Combination of Drugs with Antioxidants.

Infections caused by Schistosoma haematobium and Opisthorchis viverrini are classified as carcinogenic. Although carcinogenesis might be a multifactorial process, it has been postulated that these helminth produce/excrete oxysterols and estrogen-like metabolites that might act as initiators of their infection-associated carcinogenesis. Current treatment and control of these infections rely on a single drug, praziquantel, that mainly targets the parasites and not the pathologies related to the infection including cancer. Thus, there is a need to search for novel therapeutic alternatives that might include combinations of drugs and drug repurposing. Based on these concepts, we propose a novel therapeutic strategy that combines drugs with molecule antioxidants. We evaluate the efficacy of a novel therapeutic strategy to prevent the formation of putative carcinogenic metabolites precursors and DNA adducts. Firstly, we used a methodology previously established to synthesize metabolites precursors and DNA adducts in the presence of CYP450. Then, we evaluated the inhibition of their formation induced by drugs and antioxidants alone or in combination. Drugs and resveratrol alone did not show a significant inhibitory effect while N-acetylcysteine inhibited the formation of most metabolite precursors and DNA adducts. Moreover, the combinations of classical drugs with antioxidants were more effective rather than compounds alone. This strategy might be a valuable tool to prevent the initiation of helminth infection-associated carcinogenesis.

Metabolite profiling for biomarkers in Schistosoma haematobium infection and associated bladder pathologies.

BACKGROUND: Metabolic fingerprinting analysis can offer insights into underlying reactions in a biological system; hence it is crucial to the understanding of disease pathogenesis and could provide useful tools for discovering biomarkers. We sought to examine the urine and plasma metabolome in individuals affected by urogenital schistosomiasis and its associated-bladder pathologies. METHODOLOGY: Blood and midstream urine were obtained from volunteers who matched our inclusion criteria among residents from Eggua, southwestern Nigeria. Samples were screened by urinalysis, microscopy, PCR and ultrasonography, and categorised as advanced (urogenital schistosomiasis associated-bladder pathologies), infection-only (urogenital schistosomiasis alone) and controls (no infection and no pathology). Metabolites were extracted and data acquired with ultra high-performance liquid chromatography coupled with Thermo Q-Exactive orbitrap HRMS. Data was analysed with MetaboAnalyst, Workflow4Metabolomics, HMDB, LipidMaps and other bioinformatics tools, with univariate and multivariate statistics for metabolite selection. PRINCIPAL FINDINGS: There were low levels of host sex steroids, and high levels of several benzenoids, catechols and lipids (including ganglioside, phosphatidylcholine and phosphatidylethanolamine), in infection-only and advanced cases (FDR<0.05, VIP>2, delta>2.0). Metabolites involved in biochemical pathways related to chorismate production were abundant in controls, while those related to choline and sphingolipid metabolism were upregulated in advanced cases (FDR<0.05). Some of these human host and Schistosoma haematobium molecules, including catechol estrogens, were good markers to distinguish infection-only and advanced cases. CONCLUSIONS: Altered glycerophospholipid and sphingolipid metabolism could be key factors promoting the development of bladder pathologies and tumours during urogenital schistosomiasis.

Defining the Pathways of Urogenital Schistosomiasis-Associated Urothelial Carcinogenesis through Transgenic and Bladder Wall Egg Injection Models.

Urogenital schistosomiasis (infection with Schistosoma haematobium) is a major cause of bladder carcinogenesis. However, the exact mechanisms of the sequelae leading up to the development of bladder cancer are poorly understood, mainly because of a dearth of tractable mouse models. We developed a mouse model of urogenital schistosomiasis through intramural injection of parasite eggs into the bladder wall to mimic the trapping of parasite eggs in the bladder. This approach recapitulates many of the sequelae observed in infected humans. Here, we describe procedures for utilizing this surgical technique in combination with well-established transgenic mouse strains to dissect the role of cancer-related genes in the initiation and establishment of bladder carcinogenesis. The described method utilizes CRE-mediated flox activity to render mice p53 haploinsufficient before challenging them with bladder wall egg injection. These techniques are potentially amenable to studying the role of other pro-carcinogenic and cancer suppressor gene(s) in urogenital schistosomiasis-associated urothelial carcinogenesis.

CD4+CD25hiFOXP3+ Regulatory T Cells and Cytokine Responses in Human Schistosomiasis before and after Treatment with Praziquantel.

BACKGROUND: Chronic schistosomiasis is associated with T cell hypo-responsiveness and immunoregulatory mechanisms, including induction of regulatory T cells (Tregs). However, little is known about Treg functional capacity during human Schistosoma haematobium infection. METHODOLOGY: CD4+CD25hiFOXP3+ cells were characterized by flow cytometry and their function assessed by analysing total and Treg-depleted PBMC responses to schistosomal adult worm antigen (AWA), soluable egg antigen (SEA) and Bacillus Calmette-Guérin (BCG) in S. haematobium-infected Gabonese children before and 6 weeks after anthelmintic treatment. Cytokines responses (IFN-γ, IL-5, IL-10, IL-13, IL-17 and TNF) were integrated using Principal Component Analysis (PCA). Proliferation was measured by CFSE. PRINCIPAL FINDINGS: S. haematobium infection was associated with increased Treg frequencies, which decreased post-treatment. Cytokine responses clustered into two principal components reflecting regulatory and Th2-polarized (PC1) and pro-inflammatory and Th1-polarized (PC2) cytokine responses; both components increased post-treatment. Treg depletion resulted in increased PC1 and PC2 at both time-points. Proliferation on the other hand, showed no significant difference from pre- to post-treatment. Treg depletion resulted mostly in increased proliferative responses at the pre-treatment time-point only. CONCLUSIONS: Schistosoma-associated CD4+CD25hiFOXP3+Tregs exert a suppressive effect on both proliferation and cytokine production. Although Treg frequency decreases after praziquantel treatment, their suppressive capacity remains unaltered when considering cytokine production whereas their influence on proliferation weakens with treatment.

Immunohistochemical pattern of T lymphocytes population within bilharzial-associated bladder neoplasm microenvironment.

The present work aimed to investigate the cellular and immunochemical pattern of T cells population in biopsy material from chronic schistosomiasis haematobium Egyptian patients complicated with bladder cancer. Digital real-time quantitative photocytometry was applied to auto-analyze 29 stained tissue sections from cases and 17 controls using STAT4, GATA3, FOXP3, and CD8 markers specific for Th1, Th2, T regulatory, and T cytotoxic cells, respectively. Area percentage showed significant high level of GATA, followed by FOXP3 and low level of both STAT and CD8 was reported. Tissue samples from five healthy bladder tissues showed significant lower optical density (OD) values. Tissue samples from 12 non-bilharzial bladder cancers showed variable OD values, reflecting wide disparity in the control group.Our results hypothesized an exclusive pattern of T population in long standing complicated schistosomiasis haematobium. Our cases were poorly controlled by unbalanced Th1/Th2 in which Th2 was dominated. FOXP3 increased significantly, however, failed to downregulate Th2, instead, the relation between Th1 and T cytotoxic was forcibly limited by the high level of FOXP3, resulting in loss of their power in defending the host against both parasite and carcinogenic changes. These results provide more clarification for the immune evasion process played by the parasite and tumor cells under the supervision of T regulatory cells. Additionally a critical role of FOXP3 is suggested in manipulating STAT4 and CD8 in favor of malignant transformation in this life-threatening parasite.

In Ivorian school-age children, infection with hookworm does not reduce dietary iron absorption or systemic iron utilization, whereas afebrile Plasmodium falciparum infection reduces iron absorption by half.

BACKGROUND: In sub-Saharan Africa, parasitic diseases and low bioavailable iron intake are major causes of anemia. Anemia results from inflammation, preventing iron recycling and decreasing dietary iron absorption. Hookworm, Plasmodium, and Schistosoma infections contribute to anemia, but their influence on dietary iron absorption and recycling is unknown. OBJECTIVE: The objective was to measure inflammation biomarkers, hepcidin, iron absorption, and utilization pre- and posttreatment in children with afebrile malaria, hookworm, and Schistosoma haematobium infection. DESIGN: Ivorian children aged 11-17 y with afebrile Plasmodium falciparum (n = 17), hookworm (n = 16), or S. haematobium infection (n = 8) consumed a syrup containing 3 mg 57Fe as ferrous sulfate and received an intravenous infusion of 50 µg 58Fe as ferrous citrate. Children were treated for their respective infection, and the iron studies were repeated 4 wk later. Iron and inflammation biomarkers and hepcidin were measured. RESULTS: Geometric mean iron absorptions in the afebrile malaria and hookworm groups were 12.9% and 32.2% (P < 0.001) before treatment and 23.6% and 30.0% (P = 0.113) after treatment, respectively. Treatment of afebrile malaria reduced inflammation (P < 0.001) and serum hepcidin (P = 0.004) and improved iron absorption (P = 0.003). Treatment of hookworm infection neither affected inflammation biomarkers nor altered iron absorption. Similarly, there was a lack of treatment effects in the S. haematobium-infected group; however, the small sample size limits conclusions. Geometric mean iron utilization ranged between 79.1% and 88.0% in the afebrile malaria and hookworm groups with no significant differences pre- and posttreatment. CONCLUSIONS: In school-age children, hookworm infection does not produce inflammation or increase serum hepcidin, and it does not influence iron absorption or utilization. In contrast, afebrile malaria causes inflammation, increases hepcidin, and reduces iron absorption but not utilization. These findings provide insights into the iron metabolism and the etiology of anemia in parasitic infections.

P53 and cancer-associated sialylated glycans are surrogate markers of cancerization of the bladder associated with Schistosoma haematobium infection.

BACKGROUND: Bladder cancer is a significant health problem in rural areas of Africa and the Middle East where Schistosoma haematobium is prevalent, supporting an association between malignant transformation and infection by this blood fluke. Nevertheless, the molecular mechanisms linking these events are poorly understood. Bladder cancers in infected populations are generally diagnosed at a late stage since there is a lack of non-invasive diagnostic tools, hence enforcing the need for early carcinogenesis markers. METHODOLOGY/PRINCIPAL FINDINGS: Forty-three formalin-fixed paraffin-embedded bladder biopsies of S. haematobium-infected patients, consisting of bladder tumours, tumour adjacent mucosa and pre-malignant/malignant urothelial lesions, were screened for bladder cancer biomarkers. These included the oncoprotein p53, the tumour proliferation rate (Ki-67>17%), cell-surface cancer-associated glycan sialyl-Tn (sTn) and sialyl-Lewisa/x (sLea/sLex), involved in immune escape and metastasis. Bladder tumours of non-S. haematobium etiology and normal urothelium were used as controls. S. haematobium-associated benign/pre-malignant lesions present alterations in p53 and sLex that were also found in bladder tumors. Similar results were observed in non-S. haematobium associated tumours, irrespectively of their histological nature, denoting some common molecular pathways. In addition, most benign/pre-malignant lesions also expressed sLea. However, proliferative phenotypes were more prevalent in lesions adjacent to bladder tumors while sLea was characteristic of sole benign/pre-malignant lesions, suggesting it may be a biomarker of early carcionogenesis associated with the parasite. A correlation was observed between the frequency of the biomarkers in the tumor and adjacent mucosa, with the exception of Ki-67. Most S. haematobium eggs embedded in the urothelium were also positive for sLea and sLex. Reinforcing the pathologic nature of the studied biomarkers, none was observed in the healthy urothelium. CONCLUSION/SIGNIFICANCE: This preliminary study suggests that p53 and sialylated glycans are surrogate biomarkers of bladder cancerization associated with S. haematobium, highlighting a missing link between infection and cancer development. Eggs of S. haematobium express sLea and sLex antigens in mimicry of human leukocytes glycosylation, which may play a role in the colonization and disease dissemination. These observations may help the early identification of infected patients at a higher risk of developing bladder cancer and guide the future development of non-invasive diagnostic tests.

Nitrative DNA damage and Oct3/4 expression in urinary bladder cancer with Schistosoma haematobium infection.

To investigate whether mutant stem cells participate in inflammation-related carcinogenesis, we performed immunohistochemical analysis to examine nitrative and oxidative DNA lesions (8-nitroguanine and 8-oxodG) and a stem cell marker Oct3/4 in bladder tissues obtained from cystitis and bladder cancer patients infected with Schistosomahaematobium (S. haematobium). We also detected the expression of nuclear factor-κB (NF-κB) and inducible nitric oxide synthase (iNOS), which lead to 8-nitroguanine formation. The staining intensity of 8-nitroguanine and 8-oxodG was significantly higher in bladder cancer and cystitis tissues than in normal tissues. iNOS expression was colocalized with NF-κB in 8-nitroguanine-positive tumor cells from bladder cancer patients. Oct3/4 expression was significantly increased in cells from S. haematobium-associated bladder cancer tissues in comparison to normal bladder and cancer tissues without infection. Oct3/4 was also expressed in epithelial cells of cystitis patients. Moreover, 8-nitroguanine was formed in Oct3/4-positive stem cells in S. haematobium-associated cystitis and cancer tissues. In conclusion, inflammation by S.haematobium infection may increase the number of mutant stem cells, in which iNOS-dependent DNA damage occurs via NF-κB activation, leading to tumor development.

Targeting molecular signaling pathways of Schistosoma haemotobium infection in bladder cancer.

Since 1911 epidemiological evidence indicates that S. haematobium is associated with squamous cell carcinoma of the bladder. However, the mechanisms of this interaction are not clearly defined. Using normal epithelial cells, S. haematobium parasite extracts were able to induce cancer-like phenotypes such as proliferation, apoptosis, migration, invasion and tumorigenesis. The parasite extracts on normal urothelium also presented carcinogenic and mutagenic ability. To further elucidate the biological effects of this parasite, new estrogenic molecules were identified in its extracts. These estrogens are also present in the sera of Schistosoma-infected patients, and they have the ability to repress ER transcriptional activity both in estrogen-responsive MCF7 cells and normal urothelial HCV29 cells. This review will present some of the recent studies of mass spectrometry of S. haematobium extracts and sequence analysis of bladder tissue treated with the same extracts. Finally the molecular and cellular events that might be responsible for schistosomiasis-related bladder cancer will be discussed.

Schistosoma haematobium and bladder cancer: what lies beneath?

Schistosoma haematobium is a parasitic flatworm that infects millions of people, mostly in the developing world, and is associated with high incidence of bladder cancer although why is not clear. But our group was able to define the mechanistic relationship for the first time between infection of S. haematobium and cancer. We used in vitro models to demonstrate the presence of informative carcinogenesis-associated phenotypes in CHO cells exposed to Sh total antigen, in which we showed increased cell proliferation, decreased apoptosis, up regulation of the anti-apoptotic molecule Bcl-2, down regulation of the tumor suppressor protein p27, and increased cell migration and invasion. We further discuss the molecular and cellular events that might be responsible for schistosomiasis-related bladder cancer.

Immune events associated with protection in C57BL/6 mice immunized with anti-idiotypic antibodies mimicking protective antigens shared between gamma-irradiated cercariae vaccine and human resistance model of Schistosoma haematobium.

Immunoregulation is central for successful manipulation of schistosomiasis. Unlike schistosome vaccine development strategies that relied on direct selection of antigens from crude responses leading to selection of mildly protective antigens, the present study tested the utility of selection of potentially protective antigens encompassed rounds of immunoregulation via idiotypic network. Anti-idiotypic antibodies (Ab2) were purified from sera of New Zealand white rabbits multiply immunized with gamma-irradiated cercariae of S. haematobium, using adult worm specific idiotypes (Ab1) purified from sera of subjects resistant to reinfection. Ab2 was used for immunization of C57BL/6 mice and consequences of immunization were monitored before and after challenge infection with S. haematobium. Results showed an increase of splenic T cell expression of intercellular adhesion molecule-1 (ICAM-1) and very late antigen-4 (VLA-4) upon immunization (average % stimulated cells 54.9 vs. 20.4, P < 0.05 for ICAM-1 and 31.1 vs. 6.6, P < 0.01 for VLA-4) and challenge, especially at day 6 (83.5 vs. 45.6, P < 0.01) for ICAM-1 and day 10 (50.4 vs. 20.8, P < 0.05) for VLA-4. Thereafter, both adhesion molecules declined at day 28 through 90. Similarly, lymphoproliferation was manifested upon immunization (OD570-630 0.27 vs. 0.09, P < 0.01) and challenge at day 6 (0.5 vs. 0.17, P < 0.01) through day 10 (0.49 vs.0.18, P < 0.05), then declined at day 28 through 90. Moreover, sera of Ab2-immunized mice exhibited an anti-anti-ids (Ab3) reactivity against antigens of approximate molecular weight 40, 80 and 160 kDa of adult worms, which were also recognized by Ab1. However, in contrast to Ab1, Ab3 showed no surface binding to 3 hr schistosomula. Strikingly, mice immunized with Ab2 showed strong resistance to challenge infection (approximately 82% reduction in worm burden, P < 0.001). Taking all, this alternative vaccine development strategy appears to filter out non-protective antigens. Indeed Ab3 recognizes much fewer numbers of antigens, which passed through two rounds of immune regulation. These antigens appear to represent a significant proportion of the protective response in the gamma-irradiated cercariae vaccine and human resistance model as well, providing the basis for an alternative vaccine for schistosomiasis.

Schistosoma haematobium and Schistosomiasis mansoni: production of an estradiol-related compound detected by ELISA.

Estradiol is a steroid hormone secreted principally by the ovarian follicles in vertebrate animals. We have identified the production of an estradiol-related molecule in the trematodes Schistosoma haematobium and Schistosomiasis mansoni. We show in this work that this molecule related to estradiol is present in schistosome worm extracts. The detection method ELISA specific for estradiol, revealed the expression of this estradiol-related molecule in schistosome worm extracts, but not in Fasciola hepatica worm extracts. Our results demonstrate for the first time the production of an estradiol-related compound by a human parasite of the genus Schistosoma.

Tumor markers of bladder cancer: the schistosomal bladder tumors versus non-schistosomal bladder tumors.

BACKGROUND: The aim of this study is to comparatively elucidate the underlying molecular pathways and clinicopathological criteria in schistosomal bladder tumor (SBT) versus non-schistosomal bladder tumor (NSBT). METHODS: This study explored the role of p53, p16, bcl-2, ki-67, c-myc, Rb and EGFR, by using Immunohistochemistry assay, in 45 SBT and 39 NSBT patients in comparison with 16 schistosomal chronic cystitis (SC), 28 non-schistosomal chronic cystitis (NSC), and 20 normal control (CTL) subjects. The studied markers in SBT and NSBT were correlated with different clinicopathological criteria namely, tumor histopathology, grading, invasiveness, stage, and presentation of the disease. RESULTS: SBT was associated with high grade invasive squamous cell carcinoma (SCC) while NSBT was associated with lower grade less invasive transitional cell carcinoma (TCC). The expression of p53, bcl-2, c-myc, and EGFR was higher in SBT than in NSBT while Rb was higher in NSBT than in SBT. However, p16 and ki-67 were not different between SBT and NSBT. The profile of molecular markers in SC was similar to NSC except for EGFR which was higher in SC than in NSC. Both SC and NSC showed higher level of p53, bcl-2, ki-67, and EGFR than in CTL group while p16, Rb, and c-myc were not different. p53 was associated with high grade SCC in both SBT and NSBT. Bcl-2 was associated with high grade invasive tumors in SBT and NSBT. P16 was associated with low grade, late stage, and recurrent SBT and high grade, invasive, late stage, and recurrent NSBT. Rb was associated with SCC in SBT, invasive tumors in NSBT, and late stage and recurrent presentation in both SBT and NSBT. C-myc was associated with high grade, invasive, and late stage SBT and SCC, high grade, invasive, and late stage NSBT. EGFR was associated with invasive SCC in SBT and invasive, high grade, and late stage TCC in NSBT. ki-67 was associated with invasive SBT and high grade late stage NSBT. CONCLUSION: SBT and NSBT showed distinct molecular profile of tumor development and progression which can be taken into consideration in fine adjusting the anti-cancer therapy for SBT and NSBT.

Elevated oxidative stress and DNA damage and repair levels in urinary bladder carcinomas associated with schistosomiasis.

To cast light on mechanisms underlying development of urothelial carcinomas (UCs) of the urinary bladder associated with Schistosomiasis, we immunohistochemically analyzed the relationship between oxidative stress markers, DNA single strand breaks (ssDNA) which could also measure the levels of base damage and apoptosis in DNA, and expression of DNA repair genes with levels of nitric oxide synthases in bladder carcinomas of Egyptian patients with or without Schistosoma hematobium infection. Marked elevation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels was found in squamous cell carcinomas and UCs associated with Schistosomiasis when compared with non-Schistosomal carcinomas. This was accompanied by strong over expression of the DNA-repair genes, 8-oxoguanine-DNA-glycosylase and apurinic/apyrimidinic endonuclease, as well as increased formation levels of ssDNA. Expression levels of inducible nitric oxide synthase (iNOS) which is known to be indirectly related to oxidative stress was higher in Schistosomal than in the non-Schistosomal carcinomas. However, expression of endothelial nitric oxide synthase was slightly stronger in non-Schistosomal than in the Schistosomal carcinomas. In conclusion, these findings suggest a strong correlation between Schistosoma haematobium infection and increased levels of oxidative stress accompanied by a continuous DNA damage and repair in UCs, all directly correlating with elevated iNOS.

Analysis of fibronectin expression in the bilharzial granulomas and of laminin in the transformed urothelium in schistosoma haematobium infested patients.

UNLABELLED: The bilharzial granulomas and urothelial transformation are common findings in Schistosoma haematobium infested patients. We hypothesize that the distribution of extrinsic (fibronectin, FN) and intrinsic basement membrane (BM) proteins (laminin, LN) is altered during the evolution of these lesions. METHODS: To test this hypothesis, 70 cystectomy specimens, entailing variable associations of normal and dysplastic urothelium (all cases), and bilharzial granulomas were examined for FN and LN protein expression. RESULTS: The biharzial granulomas were formed of admixture of CD3+T cells, CD68+histiocytes and CD220B cells. The CD3+T cells and and CD68+histiocytes were the predominant cell populations. Increased deposition of FN occurred with the evolution from cellular (loose fibrillary network, 20 cases) to fibrocellualr (dense fibrillary network, 30 cases) to fibrotic (tight conglomerates, 20 cases) granulomas. Alternatively, BM staining for LN was linear and continuous underlying normal and metaplastic urothelium. In dysplastic urothelium (20 cases), it showed breaks in continuity. CONCLUSIONS: Alterations of FN and LN occur during the development of the bilharzial granuloma and urothelial transformation.

The effect of chronic lead exposure on the course of schistosomiasis in hamsters and the protective effect of the antioxidant preparation 'Antox'.

Eighty adult male hamsters were used in this study, 20 of them were divided equally into a noninfected, nontreated control group and chronic lead exposed groups, which were given lead acetate intraperitoneally, dissolved in distilled water, 2 mg/kg/day for seven weeks. Then, two experiments were carried out on the remaining animals. Each experiment included 30 animals and was divided equally into three groups. Experiment A was carried out on the following groups: Schistosoma mansoni infected group, S. mansoni infected and chronic lead exposed group and S. mansoni infected, chronic lead exposed and 'Antox' treated group. Experiment B was done following the same design except that infection was carried out using Schistosoma haematobium cercaria. Chronic lead exposure of Schistosoma infected groups showed significant reductions in worm burden, tissue egg load and ova excretion in stool, liver and intestine. Compared with the control group, there were insignificant increases in serum and hepatic glutathione and malondialdehyde levels and a significant increase in hepatic 8-oxodeoxyguanosine phosphate (8-Ox-Dg) levels in Schistosoma infected groups. However, there was a significant increase in hepatic and blood lead levels, oxidative stress parameters and in the hepatic 8-Ox-Dg level in Schistosoma infected and chronic lead exposed groups as compared with their corresponding Schistosoma only infected groups. This study revealed a significant reduction in oxidative stress parameters as well as in blood and hepatic lead levels and in hepatic 8-Ox-Dg levels after giving Antox to the Schistosoma infected and chronic lead exposed groups. However, Antox increased insignificantly all the parasitological parameters studied in the Schistosoma infected and chronic lead exposed groups.

Functional specific binding of testosterone to Schistosoma haematobium 28-kilodalton glutathione S-transferase.

During parasitic disease such as schistosomiasis, sex hormones have an important influence on the age- and gender-dependent level of infection. Since mammal glutathione S-transferase (GST) has the ability to bind hormones and particularly sexual steroids to influence their transport, metabolism, and physiological action, we have evaluated the capacity of testosterone to bind the 28-kDa GST of the Schistosoma haematobium parasite (Sh28GST). For the first time, we have demonstrated a specific binding of testosterone to parasite GST protein with high affinity (K(d) = 2.57 x 10(-7) M). In addition, we have assessed the effect of this binding on Sh28GST enzymatic activity, a mechanism closely associated with the reduction of Schistosoma fecundity. We showed that testosterone has the functional ability to inhibit the Sh28GST enzymatic activity in a dose-dependent manner, suggesting that this hormone could be directly involved in an antifecundity mechanism. This effect seemed to be related to the binding of testosterone to one peptide involved in the enzymatic site (i.e., amino acids 24 to 43). During human infection, binding of sexual hormones to Schistosoma Sh28GST could play a key role in parasite metabolism, especially the decrease of fecundity, and could be involved in the sex-dependent immune response to Sh28GST that we have previously observed in infected adults.

Patterns of expressions of transforming growth factor and epidermal growth factor receptor in squamous cell lesions of the urinary bladder.

AIM: To investigate the patterns of expression of transforming growth factor alpha (TGF-alpha) and epidermal growth factor receptor (EGFR) in squamous metaplasia and squamous cell carcinomas of the urinary bladder with and without schistosomiasis. METHODS: Immunohistochemical study of the expression of TGF-alpha and EGFR in squamous metaplasias (n = 12) and various grades of squamous cell carcinomas (n = 21) of the bladder with and without schistosomiasis. RESULTS: Focal cytoplasmic and membranous positivity for EGFR and TGF-alpha was seen in all cases of squamous metaplasia. The markers were diffusely coexpressed in a concordant pattern in areas of hyperplastic keratinising squamous metaplasia. A similar pattern of positivity was seen in verrucous carcinomas (n = 2) and well differentiated squamous carcinomas (n = 6). Progressive loss of differentiation was associated with increasing loss of EGFR staining while TGF-alpha staining was retained. Squamous cell carcinoma in situ (n = 2) showed focal positivity for TGF-alpha and EGFR. There were no differences in staining patterns between cases with and without schistosomiasis. CONCLUSIONS: The coexpression of TGF-alpha and EGFR by well differentiated squamous cell carcinomas and hyperplastic keratinising squamous metaplasia is consistent with the active regulatory role exerted by this autocrine loop. There is regional absence of expression of EGFR but not of TGF-alpha in squamous cell carcinomas of lesser differentiation, suggesting heterogeneity of such control in these tumours. The focal expression of the two markers in squamous cell carcinomas in situ indicates a possible second pathway of oncogenesis for less differentiated tumours. These observations may have important implications for the effectiveness of putative growth factor based treatments.