Exogenous bone morphogenetic protein-7 reduces hepatic fibrosis in Schistosoma japonicum-infected mice via transforming growth factor-β/Smad signaling

AIM: To investigate the antifibrotic effects of bone morphogenetic protein-7 (BMP-7) on Schistosoma japonicum (S. japonicum)-induced hepatic fibrosis in BALB/C mice.

METHODS: Sixty BALB/C mice were randomly divided into three groups, including a control group (group A, n = 20), model group (group B, n = 20) and BMP-7 treated group (group C, n = 20). The mice in group B and group C were abdominally infected with S. japonicum cercariae to induce a schistosomal hepatic fibrosis model. The mice in group C were administered human recombinant BMP-7. Liver samples were extracted from mice sacrificed at 9 and 15 wk after modeling. Hepatic histopathological changes were assessed using Masson’s staining. Transforming growth factor-beta 1 (TGF-β1), alpha-smooth muscle actin (α-SMA), phosphorylated Smad2/3 (pSmad2/3) and Smad7 protein levels and localization were measured by Western blotting and immunohistochemistry, respectively, and their mRNA expressions were detected by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS: The schistosomal hepatic fibrosis mouse model was successfully established, as the livers of mice in group B and group C showed varying degrees of typical schistosomal hepatopathologic changes such as egg granuloma and collagen deposition. The degree of collagen deposition in group C was higher than that in group A (week 9: 22.95 ± 6.66 vs 2.02 ± 0.76; week 15: 12.84 ± 4.36 vs 1.74 ± 0.80; P < 0.05), but significantly lower than that in group B (week 9: 22.95 ± 6.66 vs 34.43 ± 6.96; week 15: 12.84 ± 4.36 vs 18.90 ± 5.07; P < 0.05) at both time points. According to immunohistochemistry data, the expressions of α-SMA, TGF-β1 and pSmad2/3 protein in group C were higher than those in group A (α-SMA: week 9: 21.24 ± 5.73 vs 0.33 ± 0.20; week 15: 12.42 ± 4.88 vs 0.34 ± 0.27; TGF-β1: week 9: 37.00 ± 13.74 vs 3.73 ± 2.14; week 15: 16.71 ± 9.80 vs 3.08 ± 2.35; pSmad2/3: week 9: 12.92 ± 4.81 vs 0.83 ± 0.48; week 15: 7.87 ± 4.09 vs 0.90 ± 0.45; P < 0.05), but significantly lower than those in group B (α-SMA: week 9: 21.24 ± 5.73 vs 34.39 ± 5.74; week 15: 12.42 ± 4.88 vs 25.90 ± 7.01; TGF-β1: week 9: 37.00 ± 13.74 vs 55.66 ± 14.88; week 15: 16.71 ± 9.80 vs 37.10 ± 12.51; pSmad2/3: week 9: 12.92 ± 4.81 vs 19.41 ± 6.87; week 15: 7.87 ± 4.09 vs 13.00 ± 4.98; P < 0.05) at both time points; the expression of Smad7 protein in group B was higher than that in group A and group C at week 9 (8.46 ± 3.95 vs 1.00 ± 0.40 and 8.46 ± 3.95 vs 0.77 ± 0.42; P < 0.05), while there were no differences in Smad7 expression between the three groups at week 15 (1.09 ± 0.38 vs 0.97 ± 0.42 vs 0.89 ± 0.39; P > 0.05). Although minor discrepancies were observed, the results of RT-PCR and Western blotting were mainly consistent with the immunohistochemical results.

CONCLUSION: Exogenous BMP-7 significantly decreased the degree of hepatic fibrosis in both the acute and chronic stages of hepato-schistosomiasis, and the regulatory mechanism may involve the TGF-β/Smad signaling pathway.

Schistosoma japonicum egg antigen up-regulates fibrogenesis and inhibits proliferation in primary hepatic stellate cells in a concentration-dependent manner

AIM: To investigate the effects of different concentrations of Schistosoma japonicum (S. japonicum) egg antigen on fibrogenesis and apoptosis in primary hepatic stellate cells (HSCs).

METHODS: A mouse model of schistosomiasis-associated liver fibrosis (SSLF) was established by infecting mice with schistosomal cercaria via the abdomen. HSCs were isolated from SSLF mice by discontinuous density gradient centrifugation, and their identity was confirmed by immunofluorescence double staining of α-smooth muscle actin (α-SMA) and desmin. The growth inhibitory effect and 50% inhibitory concentration (IC50) of S. japonicum egg antigen for primary HSCs (24 h) were determined using a cell counting kit-8 (CCK-8) assay. The expression levels of α-SMA, matrix metalloproteinase-9 (MMOL/LP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in HSCs in response to different concentrations of S. japonicum egg antigen were detected by Western blotting and real-time reverse transcription-polymerase chain reaction. The levels of phospho-P38 (P-P38), phospho-Jun N-terminal kinase (P-JNK) and phospho-Akt (P-AKT) in HSCs were detected by Western blotting.

RESULTS: An SSLF mouse model was established, and primary HSCs were successfully isolated and cultured. S. japonicum egg antigen inhibited HSC proliferation in a concentration-dependent manner. The IC50 of the S. japonicum egg antigen was 244.53 ± 35.26 μg/mL. S. japonicum egg antigen enhanced α-SMA expression at both the mRNA and protein levels and enhanced TIMP-1 expression at the mRNA level in HSCs (P < 0.05), whereas the expression of MMOL/LP-9 was attenuated at both the mRNA and protein levels in a concentration-dependent manner (P < 0.05). A high concentration of S. japonicum egg antigen enhanced P-P38, P-JNK and P-AKT activation (P < 0.05). The changes in α-SMA and MMOL/LP-9 expression induced by S. japonicum egg antigen were closely correlated with P-P38 and P-JNK activation (P < 0.05). The attenuation of MMOL/LP-9 was also correlated with P-AKT activation (P < 0.05), but the increase in α-SMA expression was not. TIMP-1 expression was not correlated with P-P38, P-JNK or P-AKT activation.

CONCLUSION: S. japonicum egg antigen promotes fibrogenesis, activates the P38/JNK mitogen-activated protein kinase and AKT/PI3K signaling pathways and inhibits proliferation in primary HSCs isolated from SSLF mice in a concentration-dependent manner.

A boswellic acid-containing extract attenuates hepatic granuloma in C57BL/6 mice infected with Schistosoma japonicum

Granuloma formation has been shown to be induced and elicited by schistosome egg antigens, and it finally develops into fibrosis in intestine and the liver. Hepatic fibrosis is the main cause of increased morbidity and mortality in humans infected with schistosomes. Boswellic acid (BA)-containing extracts such as extracts of the oleogum resin from Boswellia serrata (BSE) have anti-inflammatory and immunomodulatory activity. However, little is known about the role of such extracts in schistosome egg-induced granulomatous inflammation. In order to investigate the effect of a watersoluble cyclodextrin complex preparation of BSE (BSE-CD) on Schistosoma japonicum (S. japonicum) egg-induced liver granuloma, mice infected with S. japonicum cercariae were injected with BSE-CD during egg granuloma formation. The data showed that BSE-CD significantly reduced the size of liver granuloma and levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST); however, BSE-CD treatment had no effect on worm load and egg burden. The data also showed that BSE-CD significantly decreased the expression of leukotriene B(4) (LTB(4)) and prostaglandin E(2) (PGE(2)), as well as the expression of matrix metallopeptidase 9 (MMP-9) in liver both on the mRNA and protein level. Thus, BSE-CD can significantly attenuate S. japonicum egg-induced hepatic granuloma, which may be partly dependent on the downregulation of some biochemical mediators.

Association of MICA gene polymorphisms with liver fibrosis in schistosomiasis patients in the Dongting Lake region

Major histocompatibility complex class I chain-related A (MICA) is a highly polymorphic gene located within the MHC class I region of the human genome. Expressed as a cell surface glycoprotein, MICA modulates immune surveillance by binding to its cognate receptor on natural killer cells, NKG2D, and its genetic polymorphisms have been recently associated with susceptibility to some infectious diseases. We determined whether MICA polymorphisms were associated with the high rate of Schistosoma parasitic worm infection or severity of disease outcome in the Dongting Lake region of Hunan Province, China. Polymerase chain reaction-sequence specific priming (PCR-SSP) and sequencing-based typing (SBT) were applied for high-resolution allele typing of schistosomiasis cases (N = 103, age range = 36.2-80.5 years, 64 males and 39 females) and healthy controls (N = 141, age range = 28.6-73.3 years, 73 males and 68 females). Fourteen MICA alleles and five short-tandem repeat (STR) alleles were identified among the two populations. Three (MICA*012:01/02, MICA*017 and MICA*027) showed a higher frequency in healthy controls than in schistosomiasis patients, but the difference was not significantly correlated with susceptibility to S. japonicum infection (Pc > 0.05). In contrast, higher MICA*A5 allele frequency was significantly correlated with advanced liver fibrosis (Pc < 0.05). Furthermore, the distribution profile of MICA alleles in this Hunan Han population was significantly different from those published for Korean, Thai, American-Caucasian, and Afro-American populations (P < 0.01), but similar to other Han populations within China (P > 0.05). This study provides the initial evidence that MICA genetic polymorphisms may underlie the severity of liver fibrosis occurring in schistosomiasis patients from the Dongting Lake region.

[Expression of transforming growth factor-beta1 and connective tissue growing factor in schistosomal hepatic fibrosis of mice]

OBJECTIVE

To establish the model of hepatic fibrosis in mice infected with Schistosoma japonicum and observe the expression of transforming growth factor-beta1 (TGF-beta1) and connective tissue growing factor (CTGF) in mice model.

METHODS

Thirty BALB/c mice were randomly assigned to control group and model group. Each mouse of model group was infected with (30 +/- 1) S. japonicum cercariae through the abdominal skin. Serum samples were collected at 4, 6, 8, 10, and 12 weeks after infection, and were analyzed for the levels of ALT and AST. Pathological changes and proliferation of hepatic collagen fibers in liver tissue were observed after HE staining and Masson staining. Immunohistochemistry and real-time PCR were used to detect the protein and mRNA expression of CTGF and TGF-pl.

RESULTS

6-12 weeks after infection, there was significant difference in ALT and AST between model group and control group (P43.05). At 12th week, ALT [(173.53 +/- 31.12) U/I] and AST [(301.00 +/- 34.87) U/LI in model group were higher than those in control group [(42.00 +/- 3.53) and 96.58 +/- 11.26) U/L] . In model group, egg granulomas formed in the liver, and the formation of hepatic fibrosis was significant in portal areas, and there was tree-like hepatic fibrosis around the portal vein branch. 8 weeks after infection, hepatic fibrosis area in mice of model group increased considerably, and there was significant difference in percentage of positive area of collagen between 12th week [(23.83 +/- 1.68) %] and control group [(1.23 +/- 0.14) %] (P < 0.05). 10 and 12 weeks after infection, the percentage of positive area of TGF-beta1 [(22.34 +/- 2.58)% and (25.82 +/- 3.01) %] and CTGF [(1 l.32 +/- 2.44)% and (14.51 +/- 2.05) %] was higher respectively than that of the control [(2.56 +/- 0.87)%, and (1.09 +/- 0.73)% (P < 0.05). 6, 8, 10, and 12 weeks after infection, both TGF-beta1 and CTGF mRNA increased gradually, higher than that in control group (P < 0.05). 10 weeks after infection, TGF-beta1 mRNA relative transcription level was the highest (0.0721 +/- 0.0187) and it was 0.0089 +/- 0.0037 in control group. CTGF mRNA relative transcription level reached the highest value (0.1136 +/- 0.0365) in 12 weeks after infection, while it was 0.0293 +/- 0.0184 in control group. CTGF mRNA expression was positively correlated with the duration of infection (r = 0.927, NO.05).

CONCLUSION

The area and cell types of TGFb1 positive expression is the same as that of CTGF in liver tissue of schistosome infected mice (BALB/c). CTGF mRNA expression is significantly related to the duration of infection, but it is not the case for TGFbl.

IL-10R blockade during chronic schistosomiasis mansoni results in the loss of B cells from the liver and the development of severe pulmonary disease

In schistosomiasis patients, parasite eggs trapped in hepatic sinusoids become foci for CD4+ T cell-orchestrated granulomatous cellular infiltrates. Since the immune response is unable to clear the infection, the liver is subjected to ongoing cycles of focal inflammation and healing that lead to vascular obstruction and tissue fibrosis. This is mitigated by regulatory mechanisms that develop over time and which minimize the inflammatory response to newly deposited eggs. Exploring changes in the hepatic inflammatory infiltrate over time in infected mice, we found an accumulation of schistosome egg antigen-specific IgG1-secreting plasma cells during chronic infection. This population was significantly diminished by blockade of the receptor for IL-10, a cytokine implicated in plasma cell development. Strikingly, IL-10R blockade precipitated the development of portal hypertension and the accumulation of parasite eggs in the lungs and heart. This did not reflect more aggressive Th2 cell responsiveness, increased hepatic fibrosis, or the emergence of Th1 or Th17 responses. Rather, a role for antibody in the prevention of severe disease was suggested by the finding that pulmonary involvement was also apparent in mice unable to secrete class switched antibody. A major effect of anti-IL-10R treatment was the loss of a myeloid population that stained positively for surface IgG1, and which exhibited characteristics of regulatory/anti-inflammatory macrophages. This finding suggests that antibody may promote protective effects within the liver through local interactions with macrophages. In summary, our data describe a role for IL-10-dependent B cell responses in the regulation of tissue damage during a chronic helminth infection.

Anti-inflammatory/anti-fibrotic effects of the hepatoprotective silymarin and the schistosomicide praziquantel against Schistosoma mansoni-induced liver fibrosis

BACKGROUND

Praziquantel (PZQ) is an isoquinoline derivative (2-cyclohexylcarbonyl-1, 2, 3, 6, 7, 11b-hexahydro-4H-pyrazino{2,1-a}-isoquinoline-4-one), and is currently the drug of choice for all forms of schistosomiasis. Silymarin, a standardized milk thistle extract, of which silibinin is the main component, is known for its hepatoprotective, anti-inflammatory, antioxidant activities, and hepatocyte regeneration. This study investigates the anti-inflammatory/anti-fibrotic effects of silymarin and/or PZQ on schistosomal hepatic fibrosis.

METHODS

Schistosoma mansoni-infected mice were divided into two large groups (I & II), each with four subgroups and were run in parallel. (i) Infected untreated; (ii) treated with silymarin, starting from the 4th (3 weeks before PZQ therapy) or 12th (5 weeks after PZQ therapy) weeks post infection (PI); (iii) treated with PZQ in the 7th week PI; and (iv) treated with silymarin, as group (ii) plus PZQ as group (iii). Comparable groups of uninfected mice run in parallel with the infected groups. Mice of groups I and II were killed 10 and 18 weeks PI, respectively. Hepatic content of hydroxyproline (HYP), serum levels and tissue expression of matrix metalloproteinase-2 (MMP-2), transforming growth factor-β1 (TGF-β1) and number of mast cells were determined. In addition, parasitological, biochemical and histological parameters that reflect disease severity and morbidity were examined.

RESULTS

Silymarin caused a partial decrease in worm burden; hepatic tissue egg load, with an increase in percentage of dead eggs; modulation of granuloma size, with significant reduction of hepatic HYP content; tissue expression of MMP-2, TGF-β1; number of mast cells, with conservation of hepatic reduced glutathione (GSH). PZQ produced complete eradication of worms, eggs and alleviated liver inflammation and fibrosis. The best results were obtained, in most parameters studied, in groups of mice treated with silymarin in addition to PZQ.

CONCLUSIONS

Our results point to silymarin as a promising anti-inflammatory and anti-fibrotic agent; it could be introduced as a therapeutic tool with PZQ in the treatment of schistosomal liver fibrosis, but further studies on mechanisms of silymarin and PZQ in chronic liver diseases may shed light on developing therapeutic methods in clinical practice.

Accelerated and progressive and lethal liver fibrosis in mice that lack interleukin (IL)-10, IL-12p40, and IL-13Rα2

BACKGROUND & AIMS

Progressive fibrosis contributes to the morbidity of several chronic diseases; it typically develops slowly, so the mechanisms that control its progression and resolution have been difficult to model. The proteins interleukin (IL)-10, IL-12p40, and IL-13Rα2 regulate hepatic fibrosis following infection with the helminth parasite Schistosoma mansoni. We examined whether these mediators interact to slow the progression of hepatic fibrosis in mice with schistosomiasis.

METHODS

IL-10(-/-), IL-12/23(p40)(-/-), and IL-13Rα2(-/-) mice were crossed to generate triple knockout (TKO) mice. We studied these mice to determine whether the simultaneous deletion of these 3 negative regulators of the immune response accelerated mortality from liver fibrosis following infection with S mansoni.

RESULTS

Induction of inflammation by S mansoni, liver fibrosis, and mortality increased greatly in TKO mice compared with wild-type mice; 100% of the TKO mice died by 10 weeks after infection. Morbidity and mortality were associated with the development of portal hypertension, hepatosplenomegaly, gastrointestinal bleeding, ascites, thrombocytopenia, esophageal and gastric varices, anemia, and increased levels of liver enzymes, all features of advanced liver disease. IL-10, IL-12p40, and IL-13Rα2 reduced the production and activity of the profibrotic cytokine IL-13. A neutralizing antibody against IL-13 reduced the morbidity and mortality of the TKO mice following S mansoni infection.

CONCLUSIONS

IL-10, IL-12p40, and IL-13Rα2 act cooperatively to suppress liver fibrosis in mice following infection with S mansoni. This model rapidly reproduces many of the complications observed in patients with advanced cirrhosis, so it might be used to evaluate the efficacy of antifibrotic reagents being developed for schistosomiasis or other fibrotic diseases associated with a T-helper 2 cell-mediated immune response.

[Effect of ginsenoside Rg3 on hepatic fibrosis in murine schistosomiasis japonica]

OBJECTIVE

To investigate the therapeutic efficacy of ginsenoside Rg3 on hepatic fibrosis in murine schistosomiasis japonica.

METHODS

54 ICR-strain male mice were divided into 4 groups named as normal control group (A), infected control group (B), praziquantel+Rg3 treated group (C) and praziquantel treated group (D). There were 12 mice in each group, but 18 in group A. Mice in groups B, C, and D were infected with 20 +/- 2 cercariae of Schistosoma japonicum. At ten weeks post-infection, 10 mice of group A and 12 mice of group B were weighed and sacrificed. Specimens from left hepatic lobes were taken and fixed in 10% formaldehyde solution. Mice in groups C and D were treated intragastrically with praziquantel at a single dose of 300 mg/kg. At the second day after praziquantel treatment, each mouse in group C was given 3 mg/(kg x d) ginsenoside Rg3 for 8 weeks. The rest mice were sacrificed on 8 weeks after treatment, and liver tissue samples from left hepatic lobes were prepared. The histological changes and collagen fiber deposition in the liver tissue sections were observed with hematoxylin-eosin staining and van gieson staining. Liver fibrosis was graded according to semi-quantitative scoring system (SSS) method.

RESULTS

In group B, many eggs deposited in the hepatic lobules and portal areas, and eosinophilic abscesses and pseudo-tubercles developed in the liver, especially common in portal areas. There were many fibre hyperplasia and deposit inside abbacy and liver flocculus. Pipestem fibrosis formed around the portal areas, and some cord-like fibres extended into hepatic lobules, and formed in the fibrous septa. After 8-week treatment with ginsenoside Rg3, in group C, the livers were initially enlarged, firm and dust-color; and the degree of hepatomegaly varied from mild to marked; but the degree of fibre hyperplasia and inflammatory infiltration were mitigated compared with that of group B. Mean percentage of collagen area in group C [(2.32 +/- 0.99)%] was lower than that of groups B [(11.08 +/- 4.43)%] and D [(11.19 +/- 4.91)%] (P < 0.05). The SSS scores of hepatic fibrosis in group C (2.83 +/- 1.09) was lower than that of groups B (7.42 +/- 1.16) and D (8.08 +/- 1.76) (P < 0.05).

CONCLUSION

Ginsenoside Rg3 shows anti-hepatofibrosis effects in murine schistosomiasis japonica after praziquantel treatment.

[Application of chemiluminescence immunoassay method in detection of serum index for liver fibrosis in patients with advanced schistosomiasis]

The method of chemiluminescence immunoassay (CLIA) was adopted to detect the levels of hyaluronic acid (HA), laminin (LN), III procollagen (CP III), IV collagen (IV-C) in the sera of 102 cases of advanced schistosomiasis. The results showed that the levels of the 4 indexes of advanced schistosomiasis patients were significantly higher than those of healthy people. It is suggested that the application of CLIA to detect the related serum indexes in patients with advanced schistosomiasis is useful in the diagnosis of liver fibrosis.

[Effects of signal transducers and activators of transcription 4 and 6 on development of worms and granuloma formation in mice infected with Schistosoma japonicum]

OBJECTIVE

To explore the effects of STAT4 and STAT6 on the development of worms and granuloma formation in mice infected with Schistosoma japonicum.

METHODS

All the intact BALB/cJ mice and STAT4(-/-), STAT6(-/-) mice with the same genetic background were infected with 25 S. japonicum cercariae. All the mice were sacrificed on the 42nd day after infection and the worms were collected. The total number of worms and the mean number of worm pairs were counted. The liver of each mouse was removed for the count of eggs, the histological examination and the determination of the size of single-egg granulomas in the liver.

RESULTS

No significant differences were found in the total number of worms, the number of worm pairs and the number of eggs per pair of worms in the liver among STAT4(-/-), STAT6(-/-) and BALB/cJ mice. The size of single-egg granulomas in the liver of STAT6(-/-) mice (213.3 +/- 68.6) microm was significantly smaller than that in the liver of normal BALB/cJ mice (319.5 +/- 71.9) microm (P < 0.05). The liver granulomas were not well formed and the liver fibrosis decreased in STAT6(-/-) mice.

CONCLUSIONS

STAT4 or STAT6 deficiency has no conspicuous effect on the development and fecundity of S. japonicum. STAT6 plays an important role for the granuloma formation and liver fibrosis.

Schistosoma mansoni: egg-induced downregulation of hepatic stellate cell activation and fibrogenesis

Eggs of Schistosoma mansoni trapped in human liver can lead to fibrosis. Since liver fibrosis requires activation of hepatic stellate cells (HSC) from a quiescent to a myofibroblastic phenotype, we investigated the effects of S. mansoni eggs on this process using in vitro co-cultures with human HSC and evaluated established biomarkers for activation and fibrosis. HSC demonstrate significantly reduced expression of alpha-smooth muscle actin (p<0.001), connective tissue growth factor (p<0.01) and type I collagen (p<0.001) but significantly increased expression of peroxisome proliferator-activated receptor-gamma (p<0.01). Morphologically, HSC exhibited elongated fine cellular processes and reduced size, increased accumulation of lipid droplets and reduced expression and organization of alpha-smooth muscle actin and F-actin stress fibres. Additionally, schistosome eggs prevented the HSC fibrogenic response to exogenous transforming growth factor-beta. In summary, schistosome eggs blocked fibrogenesis in HSC, a finding which may have implications for our understanding of the fibrotic pathology in S. mansoni infections.

Clinical diagnosis of Schistosoma japonicum infection complicating infective endocarditis and liver cirrhosis

Human infection with the parasite Schistosoma japonicum is rarely seen in Japan. Infection with the parasite is currently known to be endemic in China and South-east Asia, and chronic infection leads to the development of liver fibrosis, calcification and portal hypertension. We report a case of Schistosoma japonicum infection complicating infective endocarditis and liver cirrhosis. The non-invasive imaging findings and serological test were helpful to diagnose the infection with the parasite. Since Schistosoma japonicum infection is extremely rare in Japan, the diagnosis and evaluation of the patient's condition was delayed.

Slight activation of nuclear factor kappa-B is associated with increased hepatic stellate cell apoptosis in human schistosomal fibrosis

To investigate the relationship between NF-kappaB activation and hepatic stellate cell (HSC) apoptosis in hepatosplenic schistosomiasis, hepatic biopsies from patients with Schistosoma mansoni-induced periportal fibrosis, hepatitis C virus-induced cirrhosis, and normal liver were submitted to alpha-smooth muscle actin (alpha-SMA) and NF-kappaB p65 immunohistochemistry, as well as to NF-kappaB Southwestern histochemistry and TUNEL assay. The numbers of alpha-SMA-positive cells and NF-kappaB- and NF-kappaB p65-positive HSC nuclei were reduced in schistosomal fibrosis relative to liver cirrhosis. In addition, increased HSC NF-kappaB p65 and TUNEL labeling was observed in schistosomiasis when compared to cirrhosis.These results suggest a possible relationship between the slight activation of the NF-kappaB complex and the increase of apoptotic HSC number in schistosome-induced fibrosis, taking place to a reduced HSC number in schistosomiasis in relation to liver cirrhosis. Therefore, the NF-kappaB pathway may constitute an important down-regulatory mechanism in the pathogenesis of human schistosomiasis mansoni, although further studies are needed to refine the understanding of this process.

[Dynamic changes in the expression of type VI collagen in mice with schistosomal liver fibrosis]

AIM

To clarify the dynamic changes in type VI procollagen mRNA expression and collagen content in mice with schistosomal liver fibrosis.

METHODS

Northern blot hybridization and immunohistochemical technique.

RESULTS

The expression of alpha 1(VI) procollagen mRNA measured by Northern blot hybridization in the liver of schistosome infected mice was elevated significantly at 8 wk post infection, peaked at 10 wk pi, slightly decreased at 12-16 wk pi, and sustained at high levels until 20 wk pi. Immunohistochemical assay revealed that the staining pattern of type VI collagen first appeared in the walls of central veins and liver sinusoids at 8 wk pi, then extended gradually to the egg granuloma and the portal tract, within and surrounding the egg granuloma to form dense reticular septum at the 12, 16 and 20 wk pi, respectively. The VI collagen content as indicated by the intensity of stain peaked at 16 wk pi.

CONCLUSION

Both the expression of alpha 1(VI) procollagen and the content of collagen VI were significantly increased in the liver of mice with early schistosomal fibrosis, suggesting that the type VI collagen detection might be of importance for evaluating the intensity of schistosomal liver fibrosis.

[Excretory/secretory antigens from Clonorchis sinensis induces hepatic fibrosis in rats]

OBJECTIVE

To investigate the role of excretory/secretory antigens from Clonorchis sinensis (CsESAs) in hepatic fibrosis induced by C. sinensis infection in rats and explore the possible mechanism.

METHODS

CsESAs was collected from adult C. sinensis cultured in sterile condition for 12 h and injected intraperitoneally in Wistar rats. Masson staining was used to observe the changes in the hepatic collagen fiber after the injection. HE staining and immunofluorescence staining were performed to detect the expression of alpha-smooth muscle actin (alpha-SMA) to examine the proliferation and the activity of hepatic stellate cells. The specific antibody titer of CsESAs was determined using enzyme-linked immunosorbent assay to investigate the role of the antigen-antibody complex in the development of hepatic fibrosis.

RESULTS

After intraperitoneal injection of CsESAs, obvious hepatic fibrosis and hepatic stellate cell proliferation and activation were observed in the rat livers. The severity of the hepatic fibrosis was associated with the dose of CsESAs injected, whereas the titer of the specific antibody against CsESAs showed no direct relation to the hepatic fibrosis.

CONCLUSION

Intraperitoneal injection of CsESAs can cause hepatic stellate cell activation and hepatic fibrosis in rats, but the antigen-antibody complex does not seem to play the key role in the activation of the hepatic stellate cells.

[Infections in hospitalized patients with cirrhosis]

We evaluated the prevalence and the clinical relevance of bacterial and nonbacterial infections in predominantly alcoholic cirrhotic patients, admitted to an intermediate complexity hospital, and we also compared the clinical characteristics, laboratory and evolution of these patients with and without bacterial infection in a prospective study of cohort. A total of 211 consecutive admissions in 132 cirrhotic patients, between April 2004 and July 2007, were included. The mean age was 51.8 (+/-8) years, being 84.8% male. The alcoholic etiology of cirrhosis was present in 95.4%. One hundred and twenty nine episodes of bacterial infections were diagnosed in 99/211 (46.9%) admissions, community-acquired in 79 (61.2%) and hospital-acquired in 50 (38.8%): spontaneous bacterial peritonitis (23.3%); urinary tract infection (21.7%); pneumonia (17.8%); infection of the skin and soft parts (17.1%), sepsis by spontaneous bacteremia (7.7%); other bacterial infections (12.4%). Gram-positive organisms were responsible for 52.2% of total bacterial infections documented cases. There were eight serious cases of tuberculosis, fungal and parasitic infections; the prevalence of tuberculosis was 6% with an annual mortality of 62.5%; 28.1% (9/32) of the coproparasitological examination had Strongyloides stercolaris. The in-hospital mortality was significantly higher in patients with bacterial infection than in non-infected patients (32.4% vs. 13.2%; p=0.02). The independent factors associated with mortality were bacterial infections, the score of Child-Pügh and creatininemia > 1.5 mg/dl. By the multivariate analysis, leukocytosis and hepatic encephalopathy degree III/IV were independent factors associated to bacterial infection. This study confirms that bacterial and nonbacterial infections are a frequent and severe complication in hospitalized cirrhotic patients, with an increase of in-hospital mortality.

Schistosomiasis and hepatic fibrosis regression

Manson schistosomiasis is an important cause of hepatic fibrosis, a consequence of the highly fibrogenic nature of the mature schistosome eggs, the main pathogenetic factor of that disease. Thus, students interested on schistosomiasis are to be also interested on the subject of fibrosis formation and degradation since the very beginning of their studies. A brief review of the studies directly related to such interest is presented here to stress the progress obtained, and to point out to the need of further research.

Diffuse intralobular liver fibrosis in dogs naturally infected with Leishmania (Leishmania) chagasi

The aim of this study was to evaluate the diffuse intralobular fibrosis in dogs naturally infected with Leishmania (Leishmania) chagasi. One hundred five infected animals with positive serologic tests for Leishmania were divided into two clinical groups: 69 symptomatic animals and 36 asymptomatic. Special staining with Gomori, Heidenhain, Silver, and Picrosirius Red was applied to characterize fibrilopoesis. The tissue parasite load was measured by immunohistochemistry and associated histomorphometric analyses. Intralobular fibrosis was observed in all dogs, and more collagen deposition was confirmed in the infected animals than in the controls by these histomorphometric studies. There were significant differences among the distinct clinical groups. In fact, symptomatic dogs showed an increased collagen deposition in the liver compared with asymptomatic ones. A peculiar diffuse intralobular fibrosis, where the collagen fibers encircled small groups of hepatocyte(s), was observed in two cases (1.9%).

[The effects of sympathetic neurotransmitters and adrenergic receptors on liver fibrosis in murine schistosomiasis]

OBJECTIVE

To investigate the effects of sympathetic neurotransmitters and adrenergic receptors on liver fibrosis in murine schistosomiasis.

METHODS

Mice were infestated with schistosoma by means of pasting cercariae on their abdomens. Thirty mice were randomly divided into a control group and a model group. Hematoxylin eosin and Van Gieson staining were used to view the histopathology of their livers. Immunofluorescence histochemistry and laser scanning confocal fluorescence microscopy were used to measure the a1A and beta2 adrenergic receptors in livers of the two groups of mice. High performance liquid chromatography-electrochemical detector (HPLC-ECD) was used to determine the concentration of norepinephrine (NE) and dopamine (DA) in the plasma of the mice.

RESULTS

Immunofluorescence histochemistry showed that a1A and beta2 receptors were present in hepatocytes and hepatic sinusoids of the livers of the mice of the two groups, but there were many more in the livers of the schistosoma infected mice (t=-2.888; t=-6.648) (P<0.05). The results of HPLC-ECD showed that the levels of NE and DA in the model group were higher than those of the control group (t=-3.372; t=-4.428) (P<0.05).

CONCLUSION

Sympathetic neurotransmitters and adrenergic receptors may participate in liver fibrogenesis in mice infected with schistosoma.

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.

Preliminar evaluation of cytokines in the hepatitis C-schistosomiasis co-infection

Evaluation of hepatic fibrosis is usually performed by histopathological examination of biopsies. However, this is an invasive and potentially dangerous procedure. Several studies have proposed serum biological markers of hepatic fibrosis. This communication evaluates the use of serum cytokines as markers of hepatic fibrosis in hepatitis C, schistosomiasis, and co-infection.

Reversibility of schistosomal periportal thickening/fibrosis after praziquantel therapy: a twenty-six month follow-up study in Ethiopia

To study outcome determinants of schistosomal periportal thickening/fibrosis (PPT/F), 199 subjects (mean age = 24.0 years, range = 7-68 years), 109 with mild (image pattern C) PPT/F, 69 with moderate (image pattern D) PPT/F, and 21 with severe (image patterns E and F) PPT/F were treated with praziquantel and evaluated every six months for a mean duration of 26 months. Subjects excreting Schistosoma mansoni eggs during any of the six-month evaluations were offered repeat treatment. Thirty-five had some improvement, and 69 had total resolution of PPT/F, of which 63.8% resolved within one year. Compared with subjects with moderate lesions, a significantly higher proportion of subjects with mild lesions had resolution/improvement of PPT/F (40.6% versus 69.7%, P < 0.001). Subjects with severe PPT/F showed no improvement. Resolution of PPT/F was significantly more frequent at a younger age, among seronegative for hepatitis B virus and among those with a lower frequency of post-treatment recurrence of S. mansoni infections.

Prolonged somatostatin therapy may cause down-regulation of SSTR-like GPCRs on Schistosoma mansoni

BACKGROUND & OBJECTIVES

Chemotherapy with praziquantel remains the only control measure to Schistosoma mansoni infections to date. The neuropeptide hormone somatostatin gives relief from gastrointestinal disturbances, liverpathology, and reduces egg production in S. mansoni infected mice, suggesting an interaction of somatostatin with the parasite rather than with the host alone. Using antibodies directed to epitopes of the seven somatostatin transmembrane receptors (SSTRs), the presence of SSTRs (or proteins that contain these epitopes) was shown on both worm- and egg-stages of S. mansoni. The present study was undertaken to investigate whether SSTRs on S. mansoni displayed homo/heterodimerisation properties as well as agonist induced down-regulation.

RESULTS

Somatostatin therapy was effective after two days of treatment with no further reduction in pathology after five days of therapy. Immunohistochemistry performed on parasite sections showed reactivity of the anti-SSTR antibodies to the tegument and internal parts of adult S. mansoni worms. SDS-PAGE-Western blotting identified protein bands of 70-100 and 200-250 kDa molecular weight. Upon carboxymethylation of the sulfhydryl groups of proteins in the worm lysate, a reduction in density of the protein band at 200-250 kDa and an increase in density of the protein band at 70-100 kDa were noted. This suggested that a substantial amount of the proteins detected on the blot are present as a homo/heterodimer. A protein microarray was used to investigate whether somatostatin therapy induced receptor down- or up-regulation on the adult worm of S. mansoni. Slides spotted with primary anti-SSTR antibody were exposed to lysates of worms collected from infected C3H mice that received none, two days or five days somatostatin treatment, followed by a secondary anti-SSTR antibody coupled to a fluorophore. Comparison of the different samples in terms of parasite dilution till when the fluorescence was detectable, and the fluorescence intensity, proved that the proteins detected in the parasite worm have been down-regulated after five days of somatostatin treatment.

CONCLUSION

SSTR-like GPCRs are being expressed by adult S. mansoni worms and extended somatostatin treatment may cause down-regulation of these receptors, thus reducing the therapeutic capacities of this neuropeptide. However, the presence of SSTRs on S. mansoni has not yet been proven on a genetic basis. Cross-reactivity of anti-SSTR antibodies with other G-protein coupled receptors (GPCR) thus cannot yet be excluded.