Schistosoma hematobium soluble egg antigens induce proliferation of urothelial and endothelial cells

Extracellular vesicles of the liver fluke Opisthorchis felineus stimulate the angiogenesis of human umbilical vein endothelial cells

The liver fluke Opisthorchis felineus is a clinically important food-borne parasite of humans. Infection with O. felineus in mammals is associated with liver morbidities such as periductal fibrosis, bile duct neoplasia, and chronic inflammation. Previously we have shown that excretory-secretory products (ESP) can stimulate the healing of skin wounds in mice, which may be due to stimulated angiogenesis and extracellular matrix remodeling. However, there are no studies analyzing the angiogenic character of O. felineus, and its effects on angiogenesis, vascularity, and vascular endothelium. The aim of this study was to evaluate the capacity of ESP and extracellular vesicles (EVs) of O. felineus to stimulate angiogenesis and the formation of pseudo-capillaries in vitro. We also aimed at the assessment of the angiogenesis during the infection in vivo, and estimation of the endothelial cell type abundances from heterogeneous bulk liver transcriptome between uninfected and infected animals with single-cell information. The study revealed significant alterations in vascularity in the hamster liver and significant involvement of portal endothelial cells at the transcriptome level. We also demonstrated that the ESP and EVs of O. felineus have the capacity to stimulate the formation of pseudo-capillaries in vitro. Both ESP and EVs appeared to have similar effects on all four parameters, increasing node formation and total master segments length, and significantly decreasing total isolated branches length and number of isolated segments of pseudo-capillaries. The liver flukes manipulate the host's angiogenic response, a fact that has been related to the pathogenesis caused by these parasites. Understanding these pathogenic mechanisms may uncover new therapeutic targets to relieve or prevent the most severe complications of opisthorchiasis.

Bevacizumab as a potential anti-angiogenic therapy in schistosomiasis: A double-edged, but adjustable weapon

AIM

Investigating the anti-angiogenic effect of bevacizumab on chronic schistosomiasis mansoni in a trial to hinder the Schistosome-induced angiogenesis and porto-systemic shunting complications.

METHODS

The immunohistochemical expression of CD34, VEGF-R1, PCNA and α-SMA (angiogenesis markers) was analysed in the lung, liver and gastrointestinal junctions of chronic S mansoni infected mice after intraperitoneal injection of bevacizumab. The effect of prolonged administration of bevacizumab with praziquantel was also assessed through parasitic load, protective index, granuloma and fibrous tissue evaluation.

RESULTS

A regression in the vascular activity and microvascular density was observed in the infected mice after receiving bevacizumab. They had a significantly less VEGF-R1, PCNA, CD-34 and α-SMA expression in comparison to the infected untreated mice. The least tissue egg count was reported in mice received bevacizumab for 6 weeks (Mean = 27 120). However, they had persistent liver granulomas, and massively amalgamated fibrosis. Interestingly, the least faecal egg and tissue worms counts (Mean = 112, 13.4), and the highest protection index (39.26) were reported in mice received bevacizumab for 3 weeks, with marked granuloma, and fibrous tissue resolution.

CONCLUSIONS

Bevacizumab has a promising protective effect against the Schistosoma-induced angiogenesis. As an adjuvant to praziquantel, it is important to adjust the appropriate duration of administration that achieves the best schistosomicidal effect without impeding granuloma and fibrous tissue resolution.

Differential responses of epithelial cells from urinary and biliary tract to eggs of Schistosoma haematobium and S. mansoni

Chronic urogenital schistosomiasis can lead to squamous cell carcinoma of the bladder. The International Agency for Research on Cancer classifies the infection with S. haematobium as a group 1 carcinogen, a definitive cause of cancer. By contrast, hepatointestinal schistosomiasis due to the chronic infection with S. mansoni or S. japonicum associated with liver periportal fibrosis, does not apparently lead to malignancy. The effects of culturing human epithelial cells, HCV29, established from normal urothelium, and H69, established from cholangiocytes, in the presence of S. haematobium or S. mansoni eggs were investigated. Cell growth of cells co-cultured with schistosome eggs was monitored in real time, and gene expression analysis of oncogenesis, epithelial to mesenchymal transition and apoptosis pathways was undertaken. Schistosome eggs promoted proliferation of the urothelial cells but inhibited growth of cholangiocytes. In addition, the tumor suppressor P53 pathway was significantly downregulated when exposed to schistosome eggs, and downregulation of estrogen receptor was predicted in urothelial cells exposed only to S. haematobium eggs. Overall, cell proliferative responses were influenced by both the tissue origin of the epithelial cells and the schistosome species.

[Urinary schistosomiasis and cancer]

The existence of a link between urinary schistosomiasis (US) and bladder carcinoma was first suspected by C. Goebel in 1905. In 1911, A.R Ferguson, who was a professor of Pathology and Microbiology at the Faculty of Medicine in Cairo, published a more detailed survey from 40 autopsies, and reported a likely association of bladder carcinoma with granulomas caused by US. Subsequently, published results from several studies reinforced Ferguson's hypothesis. Moreover, in most countries where US was endemic, association of high prevalence of bladder carcinoma with US had been pointed out. A further circumstantial evidence was a higher prevalence of bladder squamous cell carcinoma in areas endemic for SU, whereas urothelial carcinomas were more prevalent in areas which were free of SU. However, evidence of a positive correlation between SU and bladder carcinoma was delivered only many decades later, following the results from case-control studies which were adjusted on age, sex, type of dwelling and tobacco consumption. During SU, the mechanisms underlying the onset of bladder carcinoma are still poorly understood due to the lack of any convenient animal model. Classically, two processes are thought to be involved. Chronic inflammation inside bladder would be caused by granulomas centered by eggs, and would result in a neoplasmic evolution, after years. Moreover, alteration of the bladder dynamics would elicit urine stasis which in turn would cause repeated infection of bacterial or viral origin. Beside the high prevalence of squamous cell type, the natural history of bladder carcinomas caused by SU is similar to that of other malignant tumors of the bladder. Also the treatment and prognosis are identical. Albeit genital involvement is very frequent during SU, Schistosoma haematobium does not appear to be a cause of cancers of genital organs. Schistosoma mansoni and S. japonicum have been suspected to be associated with liver or colic carcinomas, but epidemiological studies have not yielded any firm evidence so far. The entire sequencing of S. haematobium genome, along with the recent availability of a more efficient mouse model, must provide a better understanding of the genesis of bladder carcinomas during SU. However, the key for a sharp decrease in both morbidity and mortality due to SU-linked carcinomas lies in a better control of haematobium schistosomiasis, such as observed in Egypt since 1970.

Impact of density of schistosomal antigen expression in urinary bladder tissue on the stratification, cell type, and staging, and prognosis of carcinoma of the bladder in Egyptian patients

BACKGROUND

Infection with urinary schistosomiasis and its severity are oncogenic factors for developing carcinoma of the bladder, whether it is urothelial carcinoma (UC) of a transitional cell type (TCC) or non-urothelial of squamous cell carcinoma (SCC). In UC it is not defined whether it is schistosomal or not. This led to controversial results in expression of tumour markers, tumour prognosis, and response to therapy.

OBJECTIVES

We assessed the application by immunohistochemistry method (IHC) for detection of schistosomal antigen in bladder cancer tissue samples to differentiate UC associated with or without schistosomiasis. Urothelial carcinoma stage, grade, and progression were correlated with the density, intensity, and index of schistosomal antigen expression. Follow up was done for 2-5 years.

DESIGN AND PARTICIPANTS

Archival tissue samples of 575 patients were studied: 515 urothelial carcinoma, 30 patients with SCC associated with schistosomiasis, and a control group of 30 patients without schistosomiasis.

MEASUREMENTS

Expression of schistosomal antigen in tissue was done by IHC using monoclonal antibodies (MAbs) against schistosomal antigens (SA). Correlation of intensity of antigen expression to clinical and pathological data was analysed.

RESULTS AND LIMITATIONS

We identified 3 parameters of antigen expression: density, intensity and index with 4 grades for each. SCC-group was 100% positive. UC was positive in 61.4% distributed as follows: Ta: 37.5%, T1: 62%, and muscle invasive T2-4 were 64%. Upstaging, metastases and recurrence were correlated with high index in T1 and T2-4 tumours.

CONCLUSION

Urothelial carcinoma associated with schistosomiasis was defined by the positive expression of schistosomal antigens in tissues detected by lHC using MAbs against schistosomal haematobium. Upstaging and progression of T1 and T2-4 were correlated with high density, intensity, and index of antigen expression. Non-schistosomal UC had negative expression for schistosomal antigen, which was detected in 36.5% of cases. These results would be of significance in differentiating schistosomal from non-schistosomal bladder cancer of UC and would predict the prognosis in T1, T2-3 tumours. Implementation of IHC using MAbs against SA in UC would help in planning the proper therapy. Schistosomiasis should be considered as an oncogene for UC in endemic areas.

Angiogenesis and parasitic helminth-associated neovascularization

Successful metazoan parasitism, among many other factors, requires a supply of nutrients and the removal of waste products. There is a prerequisite for a parasite-defined vasculature. The angiogenic mechanism(s) involved presumably depend on the characteristics of the tissue- and vascular system-dwelling, parasitic helminths. Simplistically, 2 possibilities or a combination of both have been considered in this review. The multifactorial induction of parasitic helminth-associated neovascularization could arise through, either a host-, a parasite- or a host-/parasite-dependent, angiogenic switch. Most studies appear to support the first and third hypotheses, but evidence exists for the intrahepatic cestodeEchinococcus multilocularis, the free-living nematodeCaenorhabditis elegansand the intravascular trematodeSchistosoma mansonifor the second inference. In contrast, the nematode anti-coagulant protein NAPc2 from adultAncylostoma caninumis also an anti-angiogenic factor.

The schistosome in the mammalian host: understanding the mechanisms of adaptation

In this review, we envisage the host environment, not as a hostile one, since the schistosome thrives there, but as one in which the relationship between the two organisms consists of constant communication, through signalling mechanisms involving sense organs, surface glycocalyx, surface membrane and internal organs of the parasite, with host fluids and cells. The surface and secretions of the schistosome egg have very different properties from those of other parasite stages, but adapted for the dispersal of the eggs and for the preservation of host liver function. We draw from studies of mammalian cells and other organisms to indicate how further work might be carried out on the signalling function of the surface glycocalyx, the raft structure of the surface and existence of pores in the surface membrane, the repair of the surface membrane, the role of the membrane structure in ion channel function (including recent work on the actin cytoskeleton and calcium channels) and the possible role of P-glycoproteins in the adaptation of the parasite to its environment. We are speculative in some areas, such as the suggestions that variability in surface properties of schistosomes may relate to the existence of membrane rafts and that parasite communities may exhibit quorum sensing. This speculative approach is adopted with the hope that future work on the whole organisms and their interactions will be encouraged.

The host's genetic background determines the extent of angiogenesis induced by schistosome egg antigens

Schistosomiasis is characterised by periovular granuloma formation within the portal tract and presinusoidal venules. As inflammation wanes, continued attempts to wall off and repair hepatic injury, lead to the development of extensive fibrosis. The codependence of chronic inflammation and angiogenesis is a well-known phenomenon. Neovascularisation is a complex process of endothelial cell proliferation and remodelling of the extracellular matrix. Previous studies demonstrated the ability of schistosome soluble egg antigens (SEAs) to stimulate endothelial cell activation in vitro. In the present study, we investigated the angiogenic potential of SEA in Swiss and BALb/c mice, after infection with Schistosoma mansoni or S. haematobium and by implanting SEA-coated beads into the murine liver. Anti-CD34 and anti-Ki-67 immunohistochemical stainings demonstrated newly formed blood vessels within and at the periphery of the granulomas. However, in one third of the granulomas the pre-existing portal stroma was not destroyed by the granulomatous inflammation, angiogenesis was minimal or absent and further growth of the granuloma was prevented. In C57BL/6J and C3H/HeN inbred mice, this polarisation was even more pronounced. In 91% of the granulomas in C57BL6/J mice the portal stroma was preserved. These mice had significantly smaller granulomas, less fibrosis and less mortality as compared to the high pathology C3H/HeN mice, where 87% of the granulomas were of the angiogenic type with destruction of the pre-existing stroma, leading to more severe chronic pathology. Thus, host's genetic mechanisms regulating the degree of angiogenesis and fibrosis, determine the severity of schistosome-induced pathology.

Soluble egg antigen of Schistosoma Haematobium induces HCV replication in PBMC from patients with chronic HCV infection

BACKGROUND

This study was conducted to examine, in vitro , the effect of soluble egg antigen (SEA) of S. haematobium on intracellular HCV RNA load in peripheral mononuclear cells (PBMC) as well as on cell proliferation in patients with chronic HCV infection.

METHODS

PBMC from 26 patients with chronic HCV infection were cultured for 72 hours in presence and absence of 50 mug SEA/ml medium. Intracellular HCV RNA quantification of plus and minus strands was assessed before and after stimulation. PBMC from five healthy subjects were cultured for 7 days, flow cytometric analysis of DNA content was used to assess the mitogenic effect of SEA on PBMC proliferation compared to phytoheamaglutinine (PHA).

RESULTS

Quantification of the intracellular viral load showed increased copy number/cell of both or either viral strands after induction with SEA in 18 of 26 patients (69.2%) thus indicating stimulation of viral replication. Flow cytometric analysis showed that mean +/- S.D. of percent values of cell proliferation was induced from 3.2 +/- 1.5% in un-stimulated cells to 16.7 +/- 2.5 % and 16.84 +/- 1.7 % in cells stimulated with PHA and SEA respectively.

CONCLUSION

the present study supports earlier reports on SEA proliferative activity on PBMC and provides a strong evidence that the higher morbidity observed in patients co-infected with schistosomiasis and HCV is related, at least in part, to direct stimulation of viral replication by SEA.

Soluble egg antigen of Schistosoma Haematobium induces HCV replication in PBMC from patients with chronic HCV infection

BACKGROUND

This study was conducted to examine, in vitro , the effect of soluble egg antigen (SEA) of S. haematobium on intracellular HCV RNA load in peripheral mononuclear cells (PBMC) as well as on cell proliferation in patients with chronic HCV infection.

METHODS

PBMC from 26 patients with chronic HCV infection were cultured for 72 hours in presence and absence of 50 mug SEA/ml medium. Intracellular HCV RNA quantification of plus and minus strands was assessed before and after stimulation. PBMC from five healthy subjects were cultured for 7 days, flow cytometric analysis of DNA content was used to assess the mitogenic effect of SEA on PBMC proliferation compared to phytoheamaglutinine (PHA).

RESULTS

Quantification of the intracellular viral load showed increased copy number/cell of both or either viral strands after induction with SEA in 18 of 26 patients (69.2%) thus indicating stimulation of viral replication. Flow cytometric analysis showed that mean +/- S.D. of percent values of cell proliferation was induced from 3.2 +/- 1.5% in un-stimulated cells to 16.7 +/- 2.5 % and 16.84 +/- 1.7 % in cells stimulated with PHA and SEA respectively.

CONCLUSION

the present study supports earlier reports on SEA proliferative activity on PBMC and provides a strong evidence that the higher morbidity observed in patients co-infected with schistosomiasis and HCV is related, at least in part, to direct stimulation of viral replication by SEA.

Mutagenicity evaluation of Schistosoma spp. extracts by the umu-test and V79/HGPRT gene mutation assay

Schistosomiasis has been suspected of being a risk factor for various types of cancers for sometime, e.g., bladder cancer, colorectal cancer and hepatic cancer. Among them, the etiological relationship between urinary schistosomiasis and bladder cancer is now widely accepted. However, mechanisms of the carcinogenesis are still unclear. Here, we tested the mutagenicity of the parasite extracts by the umu-test and hypoxanthine guanine phosphoribosyltransferase (HGPRT) gene mutation assay, which both overcome disadvantages of the Ames plate assay. Adult worm extracts and egg extracts of Schistosoma haematobium and Schistosoma mansoni were tested. Under our experimental conditions, neither worm nor egg extracts were shown to have any mutagenicity in both tests even in the presence of S9 mix. Our results suggest that there is very little possibility of immediate gene mutation due to the parasite-derived substances in schistosomiasis-related carcinogenesis.

Urothelial bladder carcinoma and viral infections: different association with human polyomaviruses and papillomaviruses

Bladder cancer is the second most commonly occurring genitourinary cancer in adults. The interaction of different carcinogenic and cocarcinogenic agents are responsible for bladder urothelial carcinoma: alcohol and smoking habits, Schistosoma haematobium infection, exposition to chemicals, analgesic and antineoplastic drugs prolonged use. Recently also viral infections have been associated to this pathology. In this study the correlation between viral infections and bladder carcinoma has been evaluated. A group of 32 patients affected by primary bladder neoplasia has been analysed. A control group of 20 autoptic samples of healthy bladder was analysed. The DNA of the following viruses has been searched by polymerase chain reaction (PCR): Adenovirus, Herpes simplex virus type 1 (HSV-1), Herpes simplex virus type 2 (HSV-2), Human Papillomaviruses (HPV), Polyomaviruses (BKV and JCV). In the examined population the association bladder carcinoma-HPV, found by others, has not been confirmed. The high percentage of human polyomaviruses present in the samples is a statistically significant data (p=0.0087) and allows to presume that BKV and JCV may play a role in the aetiology of bladder tumor. In particular the polyomavirus BK, which is found in significative percentage both in single infection (p=0.0036) and in co-infections with other viral species (p=0.035), may be an important co-factor in the pathogenesis of bladder carcinoma.

Intestinal fibrovascular nodules caused by Schistosoma mansoni infection in Calomys callosus Rengger, 1830 (Rodentia: Cricetidae): a model of concomitant fibrosis and angiogenesis

Human schistosomiasis develops extensive and dense fibrosis in portal space, together with congested new blood vessels. This study demonstrates that Calomys callosus infected with Schistosoma mansoni also develops fibrovascular lesions, which are found in intestinal subserosa. Animals were percutaneously infected with 70 cercariae and necropsied at 42, 45, 55, 80, 90 and 160 days after infection. Intestinal sections were stained for brightfield, polarization microscopy, confocal laser scanning, transmission and scanning electron microscopies. Immunohistological analysis was also performed and some nodules were aseptically collected for cell culture. Numerous intestinal nodules, appearing from 55 up to 160 days after infection, were localized at the interface between external muscular layer and intestinal serosa, consisting of fibrovascular tissue forming a shell about central granuloma(s). Intranodular new vessels were derived from the vasculature of the external vascular layer and were positive for laminin, chondroitin-sulfate, smooth muscle alpha-actin and FVIII-RA. Fibroblastic cells and extracellular matrix components (collagens I, III and VI, fibronectin and tenascin) comprised the stroma. Intermixed with the fibroblasts and vessels there were variable number of eosinophils, macrophages and haemorrhagic foci. In conclusion, the nodules constitute an excellent and accessible model to study fibrogenesis and angiogenesis, dependent on S. mansoni eggs. The fibrogenic activity is fibroblastic and not myofibroblastic-dependent. The angiogenesis is so prominent that causes haemorrhagic ascites.