Hepatic schistosomiasis

Hepatic schistosomiasis, upper gastrointestinal bleeding, and health related quality of life measurements from the Albert Nile Basin

BACKGROUND

Health related quality of life measurements are vital elements of public health surveillance that uncover unmet health needs and predict the success of health interventions. We described health related quality of life measurements using the EuroQoL 5-dimension (EQ-VAS/EQ-5D) instrument and associated factors among patients with upper gastrointestinal bleeding (UGIB) and hepatic schistosomiasis at a rural health facility in the Albert Nile Basin, Uganda.

METHODS AND MATERIALS

This was a cross-sectional study at Pakwach Health Centre IV. Participants included adult inpatients and outpatients with a history of UGIB and ultrasound evidence of hepatic schistosomiasis. We evaluated and recorded each participant's medical history, physical examination, laboratory tests results, ultrasound results, and endoscopy findings. We also recorded health related quality of life measurements using the EuroQoL 5-dimension instrument and derived disability weights from EQ-VAS and EQ-5D measurements. These were our dependent variables. Descriptive and inferential statistics were generated summarizing our findings.

RESULTS

We found 103 participants had a history of upper gastrointestinal bleeding and hepatosplenic schistosomiasis. Sixty percent were between the ages of 30-49 years, 59% were females, 74% were farmers, 92% had splenomegaly, 88% had varices at endoscopy, 22% were medical emergencies with acute variceal upper gastrointestinal bleeding, and 62% had anemia. Measures of the different dimensions of health from 101 participants with patient reported outcomes revealed 77 (76%) participants experienced problems in self-care, 89 (88%) participants reported anxiety or depression, and 89 (88%) participants experienced pain or discomfort. The median EQ-VAS derived disability weights and median EQ-5D index-derived disability weights were 0.3 and 0.34, respectively. Acute upper gastrointestinal bleeding, praziquantel drug treatment, and age by decade predicted higher EQ-VAS derived disability weights (p value < 0.05). Under weight (Body mass index ≤ 18.5), acute upper gastrointestinal bleeding, ascites, age by decade, female gender, and praziquantel drug treatment predicted higher EQ-5D index- derived disability weights (p value < 0.05).

CONCLUSION

Adult patients with upper gastrointestinal bleeding and hepatic schistosomiasis from this primary health facility experience poor health and considerable health loss. Several factors predicted increased health loss. These factors probably represent key areas of health intervention towards mitigating increased health loss in this population.

Schistosomiasis Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disease of the lung blood vessels that results in right heart failure. PAH is thought to occur in about 5% to 10% of patients with hepatosplenic schistosomiasis, particularly due to S. mansoni. The lung blood vessel injury may result from a combination of embolization of eggs through portocaval shunts into the lungs causing localized Type 2 inflammatory response and vessel remodeling, triggering of autonomous pathology that becomes independent of the antigen, and high cardiac output as seen in portopulmonary hypertension. The condition is likely underdiagnosed as there is little systematic screening, and risk factors for developing PAH are not known. Screening is done by echocardiography, and formal diagnosis requires invasive right heart catheterization. Patients with Schistosoma-associated PAH show reduced functional capacity and can be treated with pulmonary vasodilators, which improves symptoms and may improve survival. There are animal models of this disease that might help in understanding disease pathogenesis and identify novel targets to screen and treatment. Pathogenic mechanisms include Type 2 immunity and activation and signaling in the TGF-β pathway. There are still major uncertainties regarding Schistosoma-associated PAH development, course and treatment.

Real-time observation of pathophysiological processes during murine experimental Schistosoma japonicum infection using high-resolution ultrasound imaging

BACKGROUND

Hepatosplenic lesion formation is one of the typical clinical symptoms of schistosomiasis japonica. Although it is established that circum-oval granuloma formation mediated by T lymphocytes is the key event triggering the formation of hepatic lesions, the time-course kinetics of disease progression remains to be fully elucidated.

METHODS

The real-time process of the pathophysiology of schistosomiasis japonica from the early to late clinical phase was non-invasively observed in a murine experimental infection model using high-resolution ultrasonography. Together with clinical parameters, including body weight and the levels of serum markers of hepatic damage or fibrosis, ultrasonography was used to assess changes in the liver parenchyma and diameter of the portal vein and portal blood flow velocity. In parallel, parasitological parameters were observed, including egg number in the feces and maturation of parasites.

RESULTS

Abnormal high-echo spot patterns in the liver parenchyma, reflecting hepatic fibrosis in ultrasonography, appeared in the liver at 4 weeks post-infection and the pattern became more enlarged and severe over time. This finding was concordant with parasite maturation and initial egg excretion. The serum M2BPGi level markedly increased from 8 weeks post-infection, suggesting sharp deterioration of hepatic fibrosis. At the same time, the diameter of the portal vein, reflecting portal hypertension, became enlarged and reached the peak level at 8 weeks post-infection. Ascites were apparent around the spleen at 9 weeks post-infection, and dilatation of the splenic vein was noted at 10 weeks post-infection. Live adult worms seemed to be detected in the portal vein at 4 weeks post-infection by ultrasonography.

CONCLUSIONS

We obtained real-time imaging of the development of hepatosplenic lesions of schistosomiasis japonica in mice. The time-course kinetics of the onset, development, and modulation of each symptom was uncovered. These results are expected to provide new clues for understanding the pathophysiology of human schistosomiasis japonica.

Pathophysiology of Portal Hypertension

The bases of our current knowledge on the physiology of the hepatic portal system are largely owed to the work of three pioneering vascular researchers from the sixteenth and the seventeenth centuries: A. Vesalius, W. Harvey, and F. Glisson. Vesalius is referred to as the founder of modern human anatomy, and in his influential book, De humani corporis fabrica libri septem, he elaborated the first anatomical atlas of the hepatic portal venous system (Vesalius 2013). Sir William Harvey laid the foundations of modern cardiovascular research with his Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (Harvey 1931) in which he established the nature of blood circulation. Finally, F. Glisson characterized the gastrointestinal-hepatic vascular system (Child 1955). These physiological descriptions were later complemented with clinical observations. In the eighteenth and nineteenth centuries, Morgagni, Puckelt, Cruveilhier, and Osler were the first to make the connection between common hepatic complications – ascites, splenomegaly, and gastrointestinal bleeding – and obstruction of the portal system (Sandblom 1993). These were the foundations that allowed Gilbert, Villaret, and Thompson to establish an early definition of portal hypertension at the beginning of the twentieth century. In this period, Thompson performed the first direct measurement of portal pressure by laparotomy in some patients (Gilbert and Villaret 1906; Thompson et al. 1937). Considering all these milestones, and paraphrasing Sir Isaac Newton, if hepatologists have seen further, it is by standing on the shoulders of giants.

Nowadays, our understanding of the pathogenesis of portal hypertension has largely improved thanks to the progress in preclinical and clinical research. However, this field is ever-changing and hepatologists are continually identifying novel pathological mechanisms and developing new therapeutic strategies for this clinical condition. Hence, the aim of this chapter is to summarize the current knowledge about this clinical condition.

Brain MR imaging changes in patients with hepatic schistosomiasis japonicum without liver dysfunction

BACKGROUND

The hyperintense signal on T1-weighted magnetic resonance (MR) images in the globus pallidus and substantia nigra of the brain can be found in patients with liver cirrhosis. The abnormality has been considered resulting from the manganese (Mn) deposition caused by liver failure and portal-systemic shunting. However, similar finding may also be found in hepatic schistosomiasis patients, who lack the biochemical evidence of liver dysfunction.

OBJECTIVES

To describe the brain MR imaging findings in patients with hepatic schistosomiasis japonicum (HSJ) without liver dysfunction.

METHODS

Brain MR and CT images of 18 patients with HSJ without liver dysfunction and 9 healthy volunteers were reviewed by two radiologists in consensus. The signal index (SI) in globus pallidus was obtained on T1-weighted images. Whole blood Mn, serum iron, serum calcium, and other laboratory tests of liver function were investigated.

RESULTS

Symmetric hyperintense signal in the globus pallidus and substantia nigra was observed in 15 of 18 HSJ patients (83.3%) and in none of controls on T1 weighted imaging. No abnormal CT findings were seen in both groups. Blood Mn level in patients was significantly higher than controls (p<0.05). Significant correlations were demonstrated between blood Mn and SI (p<0.05). No significantly abnormal results of serum iron, serum calcium and other laboratory tests were shown (p>0.05).

CONCLUSION

The portal-systemic shunting leading to Mn deposition may be the main cause of the basal ganglia hyperintense signal on T1-weighted MR imaging, which is a frequent finding in patients with HSJ without liver dysfunction.

Avaliação das citocinas IL-10 e IL-13 como mediadores na progressão da fibrose de Symmers em portadores de esquistossomose mansônica na forma hepatoesplênica

OBJETIVO: Investigar os níveis de IL-10 e IL-13 no soro de portadores da esquistossomose mansônica na forma hepatoesplênica (EHE), avaliando o papel destas citocinas no desenvolvimento da fibrose hepática. MÉTODOS: O estudo foi prospectivo e analítico, desenvolvido no Departamento de Cirurgia da Universidade Federal de Pernambuco, Laboratório de Imunologia Keizo Asami. Foram estudados três grupos: Grupo I - 25 portadores de esquistossomose mansônica na forma hepatoesplênica e não submetidos a tratamento cirúrgico; Grupo II - 30 submetidos à esplenectomia e ligadura da veia gástrica esquerda; Grupo III - 33 indivíduos sem esquistossomose mansônica na forma hepatoesplênica ou qualquer outra doença ou agravo que comprometesse a reserva funcional hepática. As concentrações séricas de IL-10 e IL-13 foram obtidas pelo método ELISA. Considerando-se a natureza não paramétrica, todas as concentrações foram analisadas pelo teste de Kruskal-Wallis. p<0,05 foi usado para rejeição da hipótese de nulidade. RESULTADOS: As médias das concentrações de IL-10, em ng/mL, no soro foram: GI 50,0 ± 59,0; GII 38,0 ± 270; GIII 38,0 ± 20,0. As concentrações de IL-13, em ng/mL, no soro dos pacientes foram respectivamente: GI 41,0 ± 93,0; GII 16,0 ± 17,0; GIII 18,0 ± 34,0. Não se observou diferença significante entre as médias das concentrações de IL-10 e IL-13 entre os grupos de estudo (p>0,05). CONCLUSÃO: As médias das concentrações séricas de IL-10 e IL-13 foram similares nos três grupos estudados, indicando que, possivelmente, estas citocinas no soro não estejam associadas aos diferentes graus de fibrose de Symmers nos pacientes.

Schistosomiasis japonica identified by laparoscopic and colonoscopic examination

A 45-year-old Philippine woman who came from Mindanao Island was admitted to our hospital with a complaint of epigastric discomfort. Abdominal ultrasonography and computed tomography demonstrated a network pattern and linear calcification in the liver. Laparoscopic examination showed numerous yellowish, small speckles over the liver surface. The liver surface was separated into many small blocks by groove-like depressions, demonstrating a so-called tortoise shell pattern. Conventional colonoscopy and narrow-band imaging showed irregular areas of yellowish mucosa, and diminished vascular network and increased irregular microvessels extending from the descending colon to the rectum. Liver biopsy showed many Schistosoma japonicum eggs in Glisson's capsule and colon biopsy showed many S. japonicum eggs in the submucosal layer. These findings established a diagnosis of schistosomiasis japonica. The present case is imported schistosomiasis japonica. Even though new cases have not occurred recently in Japan, we should remain aware of schistosomiasis japonica for patients who came from foreign epidemic areas.

The feasibility of MS and advanced data processing for monitoring Schistosoma mansoni infection

PURPOSE

Sensitive diagnosis, monitoring of disease progression and the evaluation of chemotherapeutic interventions are of prime importance for the improvement of control and prevention strategies for Schistosomiasis. The aim of the present study was to identify novel markers of Schistosoma mansoni infection and disease using urine samples from a large cohort from an area endemic for S. mansoni.

EXPERIMENTAL DESIGN

Urine samples were collected and processed on an automated sample clean-up and fractionation system combining strong cation exchange and reversed phase, and analyzed by MS (MALDI ToF MS). The ClinPro Tools(™) (CPT) software and the Discrete Wavelet Transformation-Support Vector Machine (DWT-SVM) procedure were used for classification and statistical analysis.

RESULTS

We observed a large difference in urinary peptide profiles between children and adults but classification based on infection was possible only for children. Here, in the external validation data set, 93% of the infected children were classified correctly with DWT-SVM (versus 76% for CPT). In addition 91% of low-infected children were classified correctly using DWT-SVM (versus 85% for CPT). The discriminating peptides were identified as fragments of collagen 1A1 and 1A3, and uromodulin.

CONCLUSIONS AND CLINICAL RELEVANCE

In conclusion, we provide the usefulness of a peptidomics profiling approach combined with DWT-SVM in the monitoring of S. mansoni infection.

Outcomes of Schistosoma mansoni infection in outbred albino mice exposed to Larvin contaminant

The present study tested the hypothesis that mice exposed to Schistosoma mansoni and treated with the insecticide Larvin have an increased risk of accelerated liver damage. To investigate this hypothesis, adverse effects resulting from treatment with Larvin were compared between S. mansoni-exposed and nonexposed outbred albino mice. The effects of concurrent treatment with Larvin on the progress and outcomes of S. mansoni infection were assessed via macroscopic and microscopic examination of liver and spleen, evaluation of several hematological, biochemical and hepatic enzymes parameters, and effect on worm burden. Oral administration of 1/5 and 1/10 LD(50) of Larvin to S. mansoni-exposed mice induced (1) hepatomegaly and splenomegaly; (2) prominent lymphocytic aggregation in liver replacing large areas of bridging necrosis; (3) increased serum level of bilirubin and alanine aminotransferase-aspartate aminotransferase enzymes; (4) decreased serum level of albumin and total proteins; and (5) decreased RBC, hemoglobin content, leukocyte, and lymphocyte counts. No significant effect on worm burden or oviposition was noted as a result of Larvin treatment compared to controls. All doses used in mice either for infection with S. mansoni cercariae or treatment with Larvin resulted in dose dependent alterations in hepatic functions of the tested mice. These alterations were most profound in mice exposed to S. mansoni and receiving Larvin treatment. The present findings support our hypothesis and show that concurrent S. mansoni infection with exposure to Larvin adversely affect liver functions and seriously alter hematological, biochemical, and hepatic enzymes parameters in outbred albino mice. These findings warrant further investigation and reinforce the need to minimize exposure to insecticide in both natural field settings and the broader environment.

Susceptibility of neonate mice born to Schistosoma mansoni-infected and noninfected mothers to subsequent S. mansoni infection

The present study tested the hypothesis that prenatal exposure of neonate Outbred albino mice to Schistosoma mansoni antigens (Ags) or antibodies (Abs) modulates their immunity against postnatal responses to infection. Persistence of maternal S. mansoni Abs and/or Ags in mice born to S. mansoni-infected mothers (IF-IMs) and noninfected mothers (IF-NMs) for up to 8 weeks after delivery was investigated. A higher level of anti-S. mansoni IgG Ab was detected in sera of 1-week-old mice born to IF-IM compared to controls. Then, immunoglobulin (Ig)G gradually decreased to the eight week. No anti-S. mansoni IgM Ab was detected in sera of these offspring at any week after delivery. Schistosoma Ags were detected in liver and kidney tissues of mice born to infected mothers. However, Ags decreased markedly till the sixth week in the liver but increased significantly at the sixth week in the kidney. Eight-week-old mice born to infected and noninfected mothers were infected with 200 S. mansoni ceracriae. Their sera and livers were collected for testing IgG and granuloma formation 6 weeks postinfection. Worms were collected via portal perfusion and counted. Anti-S. mansoni IgG level, size and number of liver granuloma, and worm burden were significantly reduced in the offspring of infected mothers. These data suggest that in utero exposure of Outbred albino mice to S. mansoni may attenuate the pathogenesis of S. mansoni in subsequent challenge.

Modelo experimental de formação de varizes esofágicas por hipertensão portal esquistossomótica em hamsters

OBJETIVO: Desenvolver um modelo experimental de formação de varizes esofágicas por hipertensão portal esquistossomótica em hamsters. MÉTODO: Utilizamos 55 hamsters divididos em dois grupos: grupo I composto de 50 animais infectados com injeção percutânea de 100 cercarias de Schistosoma mansoni da cepa BH; e grupo II composto de cinco animais sadios (grupo de controle). Foram mantidos por um período de incubação de oito semanas. Após este período os animais eram pesados e posteriormente avaliados cirurgicamente quanto à pressão portal, e aspectos macroscópicos e microscópicos do baço, fígado e esôfago tóraco-abdominal. RESULTADOS: Todos os animais do grupo I perderam peso, enquanto os animais do grupo II apresentavam um aumento do peso corporal durante o período de incubação. Vinte e seis (52%) animais do grupo I morreram. Dos 24 hamsters que permaneceram compondo o grupo I observamos uma pressão portal significativamente elevada quando comparada aos animais do grupo II (8,33 x 4,60 cm H2O respectivamente). Verificamos a presença de varizes esofágicas em 16 hamsters do grupo I (66,70%) sendo nestes animais a pressão portal significativamente mais elevada quando comparada aos animais do grupo I que não desenvolveram varizes (9,50 x 6,00 cm H2O respectivamente). CONCLUSÃO: É possível desenvolver em hamsters um modelo experimental de hipertensão portal esquistossomótica aguda com formação de varizes esofágicas.

Immunopathology of granuloma formation and fibrosis in schistosomiasis

In schistosomiasis the deposition of parasite ova within host tissues is the initial event in a complex pathophysiological cascade which is characterized by granuloma formation, and may terminate in fibrosis and related sequelae (Fig. 1). In spite of intensive study, the complex relationship between infection and morbidity remains poorly understood. In this article, Michael Phillips and Patrick Lammie review current concepts of the mechanisms of granuloma formation and its regulation in schistosome infections.

Noncirrhotic portal hypertension

Noncirrhotic portal hypertension represents a heterogeneous group of conditions that have distinct clinical and hemodynamic features that often help distinguish them from cirrhosis. [figure: see text] The sites of portal flow resistance may not be precisely localized to one area of the hepatic lobule and may extend beyond the site where the pathogenetic process began. Even in patients with portal hypertension caused by an increased flow, there may be subsequent development of increased resistance. The prognosis is variable; outcomes are better in patients with presinusoidal portal hypertension. A good understanding of the presentation of the various noncirrhotic conditions that cause portal hypertension will help determine the cause, the site of resistance, and the therapeutic plan. Ascites is not a feature of presinusoidal portal hypertension, whereas it may be the predominant feature in postsinusoidal portal hypertension.

Sonographic findings in noncirrhotic portal fibrosis

PURPOSE

The aim of this study was to evaluate the sonographic appearances of noncirrhotic portal fibrosis (NCPF).

METHODS

Between 1983 and 1996, 12 patients between the ages of 16 and 60 years were diagnosed with NCPF on the basis of medical history and clinical, imaging, and biopsy findings.

RESULTS

Sonograms for all patients showed hyperechoic bands surrounding the portal vein branches, which were separated from adjacent liver parenchyma by a hypoechoic stripe. All liver biopsy specimens showed nonspecific changes and no cirrhosis. Histologic findings included fibrosis and some obliteration of the intrahepatic portal veins.

CONCLUSIONS

If sonography of the liver shows increased echogenicity of the walls of the portal vessels with a hypoechoic stripe between the wall and the adjacent liver parenchyma in a patient who has portal hypertension and normal liver function tests, NCPF should be considered.

Cytokine regulation of schistosome-induced granuloma and fibrosis

Schistosomiasis mansoni, a major cause of hepatic fibrosis in many developing countries, triggers a granulomatous inflammatory reaction in response to its eggs that lodge in the liver. The egg antigens are eliminated slowly, and the persistent granulomatous response leads to prolonged matrix synthesis and hepatic fibrosis. In mice, soluble egg antigens (SEA) induce interleukin 4 synthesis, promoting a dominant T helper type 2 lymphocyte accumulation with the release of additional cytokines (IL-5, IL-10), which not only suppress Th1 lymphocyte subset cytokines, but mediate the characteristic pathophysiology. Manipulation of the cytokine profile with antagonists or exogenous cytokine delivery alters the course of the hepatic inflammation and fibrosis. In the evolution of the granulomatous response to the S. mansoni eggs, transforming growth factor beta (TGF-beta) is also produced that may modulate inflammation and regulate fibrogenesis. In TGF-beta 1-gene targeted mutant mice that over-express TGF-beta 1 (TGF-beta 1 transgenics) or in which TGF-beta 1 has been inactivated (TGF-beta 1-/-; null mutation) or partially inactivated (TGF-beta 1+/-; null mutation heterozygotes), the altered production of TGF-beta 1 impacts on S. mansoni granuloma and hepatic fibrosis. In addition to the Th1/Th2 cytokine balance, modulation of TGF-beta 1 may change the outcome of chronic inflammatory fibrotic disease.

Chronic liver disease in the Alexandria governorate, Egypt: contribution of schistosomiasis and hepatitis virus infections

BACKGROUND/AIMS

In Egypt chronic liver disease is customarily attributed to Schistosoma mansoni infection. Anti-HCV antibodies are highly prevalent among Egyptian blood donors, yet little is known about the risk factors, pathogenicity and virological features of HCV and its association with schistosomiasis. We studied 135 adult patients with chronic liver disease living in the Alexandria governorate, mostly in rural areas of the Nile Delta.

METHODS

Evaluation included abdominal ultrasonography; detection of anti-HCV antibodies and markers of HBV and HDV infection; HCV-RNA assay by 5' untranslated region nested polymerase-chain-reaction and HCV genotyping by a line probe assay; serologic (anti-soluble egg antigen, anti-SEA) and parasitological examinations for Schistosoma mansoni infection; and liver biopsy, if not contraindicated.

RESULTS

Ninety-one (67%) patients had anti-HCV and 107 (85%) anti-SEA, 32 (30%) of whom excreted schistosomal eggs in stools. In addition, 21 (16%) patients had HBsAg, 86 (64%) anti-HBc and four (3%) anti-delta. Thus, many patients had evidence of multiple infections, double in 66% (anti-HCV and anti-SEA), triple in 33% (anti-HCV HBsAg and anti-SEA). Based on our diagnostic criteria, 25 (19%) patients had schistosomal portal fibrosis (anti-HCV positive in eight), 24 (18%) chronic hepatitis (anti-HCV positive in 19), 76 (56%) cirrhosis (anti-HCV positive in 58) and 10 hepatic tumors (anti-HCV positive in six). At multivariate analysis, the presence of anti-HCV was independently associated with previous parenteral anti-schistosomal therapy, a history of hematemesis and seropositivity for anti-HBc. Fifty (55%) of 91 anti-HCV positive sera had HCV-RNA, in 41 cases classified as genotype 4a. Detection of HCV-RNA was associated with a more severe liver disease and occurred less frequently in patients with a history of schistosomiasis.

CONCLUSIONS

HCV infection with genotype 4a is the main cause of severe chronic liver disease in Egypt, where it is highly associated with schistosomiasis.

Systemic and splanchnic hemodynamic changes in patients with hepatic schistosomiasis

Although hepatic schistosomiasis is a common cause of portal hypertension, only a few hemodynamic studies, in humans, have been published on this subject. The aim of this study was to determine the systemic and splanchnic hemodynamic changes in hepatic schistosomiasis and to evaluate the influence of liver fibrosis on these changes. A retrospective analysis of a series of 13 patients with hepatic schistosomiasis who had undergone hemodynamic studies was performed. Portal or perisinusoidal fibrosis was present at liver biopsy in 8 patients. The control group included 22 patients with chronic hepatitis and normal hepatic venous pressure gradients. Patients with schistosomiasis exhibited high cardiac index (4.11 +/- 1.15 l.min-1.m-2 vs 2.99 +/- 0.85 l.min-1.m-2; p < 0.05) and low systemic vascular resistance (1039 +/- 316 dyn.s.cm-5 vs 1334 +/- 336 dyn.s.cm-5; p < 0.05). The hepatic venous pressure gradient and hepatic blood flow were normal. Azygos blood flow was markedly increased (0.90 +/- 0.66 l.min-1 vs 0.13 +/- 0.04 l.min-1; p < 0.05). Hemodynamic values were not significantly different between patients with liver fibrosis and those without fibrosis at liver biopsy. In conclusion, patients with hepatic schistosomiasis had a hyperkinetic systemic and splanchnic circulation. In patients with esophageal varices, a normal hepatic venous pressure gradient confirmed presinusoidal portal hypertension. The presence of portal or perisinuoidal fibrosis did not influence hyperdynamic splanchnic state.

The imaging diagnosis of hepatic schistosomiasis japonicum sequelae

We reviewed the ultrasound (US) and computed tomography (CT) examinations of the liver in 21 patients with hepatic schistosomiasis japonicum (HSJ), to assess the role of imaging in its diagnosis. Thirteen patients had histopathological evidence of hepatic ova deposition. A 'network' pattern was present in 14 of 17 (82%) patients on US, and 'turtle-back' calcification in 11 of 13 (85%) patients on non-contrast CT (NCCT). The combination of US and NCCT was positive for HSJ in all nine patients subjected to both investigations. These findings are specific for HSJ and we discuss how they differ from the imaging findings reported in hepatic Schistosoma mansoni (HSM). We conclude that the sequelae of HSJ infection create an imaging diagnosis. Although an uncommon incidental finding at liver imaging, the combined US and CT appearances are so characteristic that in the majority of patients biopsy can potentially be avoided.

Gene expression of transforming growth factor beta 1 and extracellular matrix proteins in murine Schistosoma mansoni infection

BACKGROUND/AIMS

The study of Schistosoma-induced hepatic fibrosis in murine Schistosoma mansoni infection has elucidated the nature of hepatic fibrosis in humans. In the present study, fibrogenic gene expression was determined in murine S. mansoni infection during primary infection, after chemotherapy with praziquantel, and during secondary infection.

METHODS

Both histomorphometric analysis and Northern blot profiles were performed.

RESULTS

Histomorphometric analysis of granulomatous inflammation showed smaller hepatic fibrotic granulomata after chemotherapy and during secondary infection. Albumin gene expression remained relatively constant throughout primary infection, chemotherapy, and secondary infection. Fibronectin gene expression in primary infection was comparable with the level observed in noninfected mice and was reduced by chemotherapy. Reinfection resulted in augmented expression levels equal to primary infection levels. Osteonectin gene expression was active in primary infection, was reduced by chemotherapy, and was actively reexpressed in secondary infection. Interstitial matrix macromolecules, types I and III collagen, and basement membrane collagen showed high levels of gene expression in primary infection, were virtually terminated by chemotherapy, and were reexpressed on reinfection. The gene expression of transforming growth factor beta 1, a major, fibrogenic cytokine, paralleled collagen expression.

CONCLUSIONS

Chemotherapy of schistosomiasis initiated a dramatic decrease in steady-state messenger RNA levels of major proteins associated with fibrosis; reinfection resulted in a reexpression of these genes.

Hepatic fibrosis and gene expression changes induced by praziquantel treatment during immune modulation of Schistosoma japonicum infection

In the present study fibrogenic gene expression was determined in murine Schistosoma japonicum infection during the progression of immune modulation of infection and following chemotherapy during the course of immune modulation. Histomorphometric analysis of granuloma size and collagen deposition revealed peak granuloma size in acute infection (5 weeks) and peak hepatic collagen content at 16 weeks of infection. Peak Type I collagen gene expression was concomitant with TGF-beta 1 gene expression at 8-11 weeks. Chemotherapy during either acute (9 weeks) or chronic (24, 28 weeks) infection resulted in increased collagen deposition and increased gene expression of Type I collagen and TGF-beta 1. However, chemotherapy at 14-16 weeks resulted in decreased levels of TGF-beta 1 gene expression and essentially minimal change in Type I collagen deposition and gene expression. These data indicate that chemotherapy of schistosomiasis japonica does not reverse hepatic fibrogenesis when administered in acute infection-when granuloma size is maximal-or in chronic infection. However, a beneficial effect on hepatic fibrogenesis is seen when chemotherapy is administered at 14-16 weeks post-infection, a time of decreasing granuloma size and maximal hepatic collagen content. Thus the ability to reverse schistosomal-induced hepatic fibrogenesis by chemotherapy may depend on disease stage.

Aminoterminal propeptide of type III procollagen: a marker of disease activity in schistosomal patients

The serum concentration of aminoterminal propeptide of type III procollagen was measured in 44 Egyptian healthy controls and 29 patients with hepatosplenomegaly originating from endemic areas for schistosomiasis in Egypt. Patients were classified into two main groups according to the histopathological pattern of the liver biopsy: patients with active schistosomal liver fibrosis and patients with inactive schistosomal liver fibrosis. Serum aminoterminal propeptide of type III procollagen levels were elevated in most of patients with active fibrosis but not in those with inactive schistosomiasis. From the present work, it is suggested that aminoterminal propeptide of type III procollagen can be used as a marker for active fibrogenesis in patients with schistosomal liver fibrosis.

Oesophageal varices in a region of the Sudan endemic for Schistosoma mansoni

In a field study of two villages in the Gezira, an area of the Sudan endemic for Schistosoma mansoni, liver ultrasonography was used to detect subjects with Symmers' hepatic periportal fibrosis, some of whom underwent oesophagoscopy to detect oesophageal varices. The prevalence of oesophageal varices in subjects undergoing oesophagoscopy was 54 per cent and 67 per cent respectively, occurring mainly in males aged about 30 years. The varices were usually asymptomatic. Symptomatic varices (with a positive history of haematemesis) occurred in 4 per cent and 3 per cent respectively of subjects with sonographic evidence of liver periportal fibrosis. By detecting oesophageal varices in an asymptomatic phase, hepatic ultrasonography and fibreoptic oesophagoscopy may elucidate the natural history of the varices and their response to periodic anti-schistosomal chemotherapy.

Clinical pharmacokinetics in patients with liver disease

From considerations of hepatic physiology and pathology coupled with pharmacokinetic principles, it appears that altered drug elimination in liver disease may result from the following mechanisms: reduction in absolute cell mass, in cellular enzyme content and/or activity, in portal vein perfusion due to extrahepatic/intrahepatic shunting, or of portal perfusion of hepatocyte mass due to decreased portal flow or sinusoidal perfusion; increase in arterial perfusion relative to portal perfusion; preferential perfusion of the sinusoidal midzone and terminal zones by arterioles; potential for direct mixing of arterial blood within the space of Disse; reduced exchange across the endothelial lining; and impaired diffusion within the space of Disse. In general, oxidative drug metabolism is impaired in liver disease and the degree of impairment of oxidisation differs between drugs but correlates best with the degree of sinusoidal capillarisation, i.e. the degree of access of the drug from the sinusoid to the hepatocyte. Drug conjugation appears to be relatively unaffected by liver disease, whereas elimination by biliary excretion correlates best with the degree of intrahepatic shunting and not with sinusoidal capillarisation. As the latter should impair hepatocyte access of all compounds similarly, a potentially important mechanism could be impaired access of oxygen to hepatocytes as oxidative metabolism is much more sensitive to oxygen supply than are conjugation or biliary excretion. This suggests a potentially important therapeutic role for agents which increase the hepatic oxygen supply. Useful adjunctive strategies may also derive from the oxygen limitation hypothesis. Anaemia should be targeted as a critically important variable, as should oxygen-carrying capacity, i.e. modification of the smoking habit. Additionally, enzyme inducers such as barbiturates may be used if overriding hypoxic constraints are removed by oxygen supplementation. Agents likely to seriously compromise arterial perfusion of the hepatic vascular bed should be avoided, e.g. those causing postural hypotension or vasospasm. Vasodilators can be used to actively promote arterial perfusion. While the effect of liver disease on drug handling is highly variable and difficult to predict, there are well recognised principles for modifying dosage. These include halving the dose of drugs given systemically (or of low clearance drugs given orally) and a 50 to 90% reduction in the dose of drugs with a high hepatic clearance given orally. Changes in the pharmacodynamic effects of drugs (either alone or in addition to pharmacokinetic changes) can also be profound, and awareness of this possibility should be increased.

Should both schistosomal and nonschistosomal variceal bleeders be disconnected?

Splenopancreatic disconnection (SPD) was conceived and implemented as a technical addition to distal splenorenal shunt (DSRS) to maintain its selectivity and preserve portal perfusion. The proposed hemodynamic and metabolic stability of hepatocytes after DSRS-SPD should improve survival. In this nonrandomized study, 145 consecutive (Child A/B) variceal bleeders were electively subjected to selective shunt with DSRS in 93 and DSRS-SPD in 52 patients. The 2 groups were similar before surgery with a mean follow up of 24 +/- 12 (DSRS) and 27 +/- 14 (DSRS-SPD) months. DSRS-SPD had an operative mortality of 3.8%. Postoperative pancreatitis occurred in 7.7% after DSRS-SPD and 3.2% after DSRS alone, with schistosomal hepatic fibrosis representing 86% of morbid cases. Shunt patency was high and recurrent variceal hemorrhage was low in both groups. Clinical encephalopathy was significantly reduced after DSRS-SPD (p less than 0.05). The addition of SPD significantly reduced both the incidence of chronic hyperbilirubinemia in the schistosomal patients (p less than 0.05) and the difference between the changes in total serum bilirubin in all patients (p = 0.001). Portal perfusion was preserved after DSRS-SPD in all of the angiographically-studied patients. The overall survival was 84% after DSRS and 88% after DSRS-SPD. The schistosomal patients showed an incidence of 95% and 96% survival after DSRS and DSRS-SPD, respectively. DSRS-SPD was able to improve survival (92%) better than DSRS (77%) among well-matched nonschistosomal patients. These data show: (1) DSRS-SPD still has low operative mortality and a high patency rate with a low incidence of recurrent variceal hemorrhage, (2) DSRS-SPD maintains portal perfusion, achieves better survival, and reduces the incidence of encephalopathy, especially in patients with nonalcoholic cirrhosis and mixed liver disease, (3) in the schistosomal population, DSRS-SPD reduces the incidence of chronic hyperbilirubinemia but increases the risk of postoperative pancreatitis.

Propranolol ameliorates the development of portal-systemic shunting in a chronic murine schistosomiasis model of portal hypertension

We investigated the role of early portal hypotensive pharmacotherapy in preventing the development of portal-systemic shunting in a portal hypertensive model of chronic murine schistosomiasis induced by infecting C3H mice with 60 cercariae of Schistosoma mansoni. Propranolol was administered in drinking water to 20 animals for a period of 6 wk at a dose of 10 mg.kg-1d-1, starting at 5 wk of schistosomal infection. 32 age-matched mice with chronic schistosomal infection served as controls. All animals were studied 11 wk after the infection. Compared with controls the portal pressure (10.8 +/- 0.40 mmHg) was significantly lower (P less than 0.001) in the propranolol-treated animals (7.9 +/- 0.80 mmHg). Portal-systemic shunting was decreased by 79%, from 12.2 +/- 3.34% in controls to 2.5 +/- 0.99% in the propranolol group (P less than 0.05). Portal venous inflow was reduced by 38% in the propranolol treated animals (2.50 +/- 0.73 ml/min; n = 6) compared with controls (4.00 +/- 0.34 ml/min; n = 8; P less than 0.05). The worm burden, the granulomatous reaction, the collagen content of the liver, and the serum bile acid levels were not significantly different between the two groups of animals. These results demonstrate that in chronic liver disease induced by schistosomiasis, the development of portal-systemic shunting can be decreased or prevented by the reduction of flow and pressure in the portal system.

Abnormal growth hormone dynamics in chronic liver disease do not depend on severe parenchymal disease

Abnormal basal serum levels of growth hormone (GH) and abnormal GH dynamics have been observed in patients with alcoholic cirrhosis (AC). To further characterize these abnormalities, patients with AC or schistosomal hepatic fibrosis (SHF) were evaluated. The former patients have parenchymal liver disease, portal hypertension, and portosystemic shunting. SHF, in contrast, is characterized by periportal fibrosis with minimal or no parenchymal cell disease, portal hypertension, and portosystemic shunting. We studied 20 patients with SHF and normal stature and 15 patients with AC. In these two groups of patients, basal serum GH was higher than normal (P less than .01). A paradoxical increase in GH was observed during the oral glucose tolerance test (OGTT) in 55% of SHF and in 40% of AC patients. Significant GH elevation followed thyrotropin-releasing hormone (TRH) administration in 80% of SHF and 66% of AC patients, but not in normals. Serum nonsuppressible insulin-like activity (NSILA) and serum somatomedin C (Sm-C) levels were reduced significantly in both groups. In SHF patients, the paradoxical increase in GH during OGTT correlated inversely with Sm-C (r = -.6, P less than .05). We conclude that (1) abnormal GH secretion occurs in both SHF and AC, (2) serum Sm-C and NSILA are diminished in both forms of liver disease, and (3) portosystemic shunting of blood appears to be the important pathology shared by both forms of liver disease.

Praziquantel in the treatment of hepatosplenic schistosomiasis: biochemical disease markers indicate deceleration of fibrogenesis and diminution of portal flow obstruction

Serological indicators for disease activity and portal vein obstruction and/or deviation were assessed in 23 patients with hepatosplenic schistosomiasis before, and up to 18 months after, praziquantel treatment, as well as in 25 matched local controls. Cessation of egg-induced immunopathology was reflected by the return to normal of serum procollagen-III-propeptide and neopterin concentrations. Reversibility of portal vein pathology was indicated by normal clearance of cholylglycine in cases without signs of decompensating portal hypertension. In most patients with a history of ascites and/or haemorrhage, serum cholylglycine concentration remained pathological. The results provide evidence that the fibrogenic process ceases after specific chemotherapy, and that portal vein pathology regresses in a substantial proportion of hepatosplenic schistosomiasis cases.

Hemodynamic mechanisms of emerging portal hypertension caused by schistosomiasis in the hamster

A hamster model of schistosomiasis has provided the first opportunity to sequentially examine the early phases of the development of portal hypertension in a natural model of chronic liver disease. Groups of hamsters were infected with 50 cercariae of Schistosoma mansoni and underwent hemodynamic evaluation at intervals of 5, 8, 12 and 20 wk after infection. A progressive rise in intrahepatic resistance (from 4.0 +/- 0.4 to 8.4 +/- 1.0 mm Hg min.ml-1.gm liver weight [p less than 0.01]) appeared to play a major role in the initial stages of evolving portal hypertension. A gradual decline in portal blood flow (from 2.1 +/- 0.3 to 1.3 +/- 0.1 ml.min-1.gm-1 liver weight [p less than 0.01]) was only partially compensated for by an increase in hepatic arterial flow. Accordingly, by week 20, total hepatic blood flow decreased 23%. Liver weight that increased markedly between 5 and 12 wk after infection, as a result of the acute accumulation of obstructing granulomas, stabilized between wk 12 and 20, while a gradual but progressive rise in hepatic collagen content was seen. Portal pressure increased 75% during the study period. Chronic examination of this natural model should help define the pathogenesis of the complications of portal hypertension and contribute to the basis for effective intervention in this disease process.

Immunopathology of Schistosoma mansoni infection

Schistosomiasis mansoni is a chronic helminthic disease that affects about 100 million people in the tropics. The worms have a life span of 5 to 10 years, and they live in the mesenteric veins of the host. Lightly infected individuals are asymptomatic or manifest mild intestinal symptoms. Heavily infected individuals often develop severe morbidity with hepatosplenomegaly, sometimes with a fatal outcome. Morbidity is attributed to the strong humoral and T-cell-mediated host immune responses developed to a variety of parasite antigens and expressed as tissue inflammations. The immunopathology includes dermatitis, immune complex-mediated kidney disease, and, chiefly, T-cell-mediated granuloma formation and fibrosis around disseminated parasite eggs. This review describes the mechanisms of induction and expression of immunopathology in infected persons and experimental animals. Immunoregulatory mechanisms that modulate the enhanced immune responses and may ameliorate excessive morbidity are discussed.

Schistosomal versus nonschistosomal variceal bleeders. Do they respond differently to selective shunt (DSRS)?

The distal splenorenal shunt (DSRS) was performed in 125 consecutive variceal bleeders. To date, no patients have been lost to follow-up (mean of 79 +/- 20 months). Liver pathology was documented in 85 patients: 45 patients had schistosomal hepatic fibrosis, 17 had nonalcoholic cirrhosis, and 23 had mixed pattern (hepatic fibrosis and cirrhosis). The preoperative data base for these three groups was matched (p greater than 0.05), with a mean follow-up of 79 +/- 20, 70 +/- 14, and 77 +/- 22 months for each population, respectively. The results showed low operative mortality (4.8%), high cumulative patency rate (94.8%) and low recurrent variceal hemorrhage (5.6%). The biochemical data showed significant increase in serum bilirubin (p less than 0.001) and aspartate transaminase (AST) (p less than 0.05) in the nonschistosomal patients. Chronic hyperbilirubinemia was found in 33% of the schistosomal group. Prograde portal perfusion was detected in 94% of the patients, with development of collaterals in 91%. The angiographic pattern of these collaterals was 50% pancreatic, 45% gastric, and 26% colosplenic. Patients with mixed liver disease had a high incidence of Grade III portal perfusion (57%) and more common pancreatic and gastric collaterals (71%). The cumulative survival for all patients was 74.1%, with hepatic cell failure being the leading cause of death (13 patients, 50% of all deaths). The schistosomal patients had a 91.6% incidence, whereas the cirrhotic and mixed groups had survival rates of 75.6% and 65.2%, respectively. Also, of a 15% total incidence of encephalopathy, 4.4% was related to the schistosomal patients, 23.5% to the cirrhotics, and 21.7% to the mixed population. Statistically, the survival rate was significantly better (p less than 0.05) and encephalopathy was significantly lower (p less than 0.05) in the schistosomal population. In conclusion, this data shows that: 1) DSRS has a high patency rate and a low variceal hemorrhage recurrence rate; 2) it maintains some degree of portal perfusion in patients with different nonalcoholic liver diseases, despite development of collaterals; and 3) the schistosomal patients have a better survival rate, with a low incidence of encephalopathy after DSRS, compared with the cirrhotic and mixed populations.

Dynamics of hepatic connective tissue matrix constituents during murine Schistosoma mansoni infection

Hepatic fibrosis is the major clinical sequela of infection with the helminth Schistosoma mansoni. However, little is known regarding its dynamics and regulation in schistosomiasis. The present study presents the dynamics of deposition and resorption of two major extracellular matrix components of fibrosis, glycosaminoglycans and collagens, during the course of experimental S. mansoni infection. Early in infection (6 weeks), glycosaminoglycan biosynthesis was markedly elevated, as was collagen biosynthesis. This led to significant accumulations of these two molecules at a glycosaminoglycan/collagen ratio similar to that observed in livers of uninfected mice (uronic acid/hydroxyproline ratio of 1.10 at 6 weeks compared to normal value of 1.25). During maximal hepatic fibrosis (12 to 18 weeks), both collagen and glycosaminoglycan biosynthesis continued to increase but the extracellular matrix shifted to a lower glycosaminoglycan/collagen ratio of 0.42, suggesting enhanced glycosaminoglycan breakdown. In addition, during this acute stage of infection, Type I collagen was the predominant isotype synthesized, whereas total collagenolytic activity degrading Type I collagen was maximal. During chronic infection, a decrease in the content of both hepatic glycosaminoglycans and collagens were noted, with a glycosaminoglycan/collagen ratio of 0.63. Decreased glycosaminoglycan content paralleled diminished biosynthetic rates. On the other hand, an over 50% reduction in collagen content (from 18 to 24 weeks) appeared not to result from diminished biosynthesis but from a switch in the predominant collagen isotype synthesized (from Type I to Type III), matched by an enhanced constitutive collagenolytic activity directed toward this type of collagen.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of chemotherapy on hepatic collagen and glycosaminoglycan metabolism in Schistosoma mansoni-infected mice

The dynamics of biosynthesis and accumulation of collagenous proteins and glycosaminoglycans (GAGs) in liver granulomas induced by eggs of Schistosoma mansoni were studied in mice following eradication of adult worms by chemotherapy. The relatively synchronous granulomas around parasite eggs were isolated from the livers at ensuing 2-week intervals; the number of recoverable granulomas per liver gradually decreased and was 7% of initial values at 20 weeks. Hepatic or granuloma-associated extracellular matrix components increased for 4 weeks after treatment despite cessation of ova deposition. At 12 weeks after chemotherapy the rate of GAG biosynthesis per total liver granuloma fraction, measured by 3H-glucosamine incorporation, decreased dramatically; this was followed by a decrease in the amount of GAGs present. The rate of collagen biosynthesis per total liver granuloma fraction, measured by 3H-proline incorporation, began to decline at 14 weeks and a decrease in the amount of collagen present was noted at 16 weeks. Our results demonstrated that liver granulomas induced by S. mansoni eggs synthesize collagens and GAGs for about 4-6 weeks following parasitological cure. The subsequent resolution of granulomas proceeds first by a reduction in GAG biosynthesis followed 4-8 weeks later by decreased collagen biosynthesis, followed by accelerated resolution of both collagen and GAGs.

Effect of praziquantel on hepatic fibrosis in experimental Schistosomiasis mansoni

The effect of specific chemotherapy on hepatic fibrosis was studied in Swiss albino mice infected with Schistosoma mansoni. The effect of treatment with praziquantel at 8, 12, and 20 weeks postinfection on fibrosis was assessed by determination of total hepatic collagen content, ratio of type III/I + III collagen, granuloma volume, and histopathological examination of liver section. Total collagen content was reduced in mice treated at the 8th week of infection compared to respective infected controls. The ratio of type III/I collagen was within normal limits. The decrease in collagen deposition was not observed when treatment was given 12 or 20 weeks postinfection. Early specific treatment of schistosomiasis may be important in the therapeutic approach to the control of morbidity in schistosomiasis.

Liver involvement in human schistosomiasis mansoni. Assessment by immunological and biochemical markers

In 20 patients with hepatic or hepatosplenic schistosomiasis and 82 individuals infected with S. mansoni, but without liver enlargement, serum parameters reflecting the fibrotic process and hemodynamic alterations as well as immunomodulation were examined. Included as controls were 35 age- and sex-matched healthy individuals from the study region in Northeast Brazil. Peripheral blood cholylglycine levels in patients with hepatomegaly, reflecting the spillover of portal blood into the systemic circulation, were elevated 12-fold over values of patients without liver involvement. Procollagen-III-peptide, a cleavage product of collagen synthesis, was elevated in patients with hepatomegaly (P less than 0.001) but normal in uncomplicated cases. Immunomodulation was assessed by in vivo delayed hypersensitivity to recall antigens and by serum beta 2-microglobulin and neopterin, substances released in the context of lymphocyte activation. Neopterin, predominantly a macrophage product, was elevated most strikingly in hepatomegalic cases (P less than 0.001). The possible interrelation between altered immune responses and excess fibrogenesis is discussed.

Propranolol disposition in patients with hepatosplenic schistosomiasis

Eight Sudanese patients with hepatosplenic schistosomiasis and seven Sudanese controls were administered a single oral dose of long acting (LA), propranolol 160 mg; blood propranolol levels were measured at regular intervals for 12 h using g.l.c. In patients with hepatosplenic schistosomiasis, propranolol blood concentrations were greater (P less than 0.05) at all time intervals, Cmax 63.5 (29-143) ng ml-1 (median and range) than controls Cmax 23 (12-37) ng ml-1. Median AUC0-12 was also greater (P less than 0.05) (533 and 218 ng ml-1 h respectively), tmax were not significantly different. In patients and controls prior to treatment, standing heart rate (77.5 (60-110), 72 (68-74) beats min-1) systolic (120 (105-150), 110 (100-120) mm Hg) and diastolic blood pressure (75 (60-90), 70 (60-80) mm Hg) were not significantly different. However following propranolol administration a reduction (P less than 0.05) occurred in both systolic (median 20 mm Hg) and diastolic (median 12.5 mm Hg) blood pressure in the patients compared with controls. Heart rate was reduced by a median of 10 beats min-1 in both groups. These observations indicate that propranolol bioavailability in patients with hepatosplenic schistosomiasis is increased possibly due to reduced presystemic extraction.

Collagen isotypes, laminin, and fibronectin in granulomas of the liver and intestines of Schistosoma mansoni-infected mice

Patterns of fibrosis within hepatic and intestinal granulomas of Schistosoma mansoni-infected mice were analyzed by indirect immunofluorescence. Deposition of collagen isotypes, laminin, and fibronectin was evaluated semiquantitatively between 8 and 20 weeks of the infection. Liver granulomas were the largest at 8 weeks and contained low amounts of type I and higher amounts of type III collagen and fibronectin. Collagen deposition became pronounced as infection progressed. The relative amounts of type I collagen deposits rose and equalled that of type III. In the smaller immunomodulated granulomas at 20 weeks both types I and III were high, and type IV collagen deposition was observed. Fibronectin and laminin deposits were also detected. The small ileal granulomas did not change their size during the course of the infection. At 8 weeks, connective tissue matrix deposition was barely detectable within these lesions. Gradually, small deposits of types I and III appeared in equal amounts and attained highest levels by 20 weeks of the infection. Fibronectin deposits at that time were very prominent but laminin and type IV collagen were absent. Colon granulomas at 8 weeks of the infection were only somewhat smaller than those of the liver, yet contained very sparse deposits of types I and III collagen. During the ensuing weeks collagen deposits rose only slightly. By 20 weeks the granulomas diminished in size and within those lesions type III collagen was predominant. Whereas the presence of fibronectin was pronounced, type IV collagen and laminin were detectable only in trace amounts. These observations indicate the existence of important organ-related differences in the intragranulomatous deposition of connective tissue matrix.

Transcriptional and posttranscriptional effects of dexamethasone on albumin and procollagen messenger RNAs in murine schistosomiasis

We have previously shown that dexamethasone increases albumin mRNA and decreases procollagen steady-state mRNA levels in rat hepatocyte cultures. These studies were extended by evaluating an in vivo model of fibrogenesis (murine schistosomiasis) and by determining a more precise level of gene expression responsible for these changes. Control mice and litter mates infected with Schistosomiasis mansoni were evaluated at 8 weeks postinfection when the livers of the infected mice had become fibrotic and their serum albumin levels significantly decreased. The addition of 4 micrograms/mL dexamethasone to the drinking water of half of the infected mice led to a 75% decrease in the liver collagen content as determined by high-performance liquid chromatography. RNA was extracted from the livers of mice under three conditions: control and infected +/- dexamethasone. This RNA was then hybridized with cDNA probes to determine steady-state levels of specific mRNAs. In the infected mice, albumin mRNA levels were decreased compared to control; however, infected mice treated with dexamethasone increased their albumin mRNA content by 3-fold at 8 weeks. Types I and IV procollagen steady-state mRNA levels in infected mice were increased compared to control while dexamethasone suppressed the mRNA level of collagen in infected mice by 50%. The level of gene expression responsible for these steady-state changes was evaluated by nuclear run-on analysis. While the effect of schistosomiasis on these genes was primarily at a transcriptional level, dexamethasone exerted its effect on different genes in the injured liver by diverse mechanisms, i.e., decreasing collagen synthesis at a transcriptional level and increasing albumin by posttranscriptional mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Dynamics of hepatic glycosaminoglycan accumulation in murine Schistosoma japonicum infection

Hepatic fibrosis is the major pathologic sequela of schistosomiasis and is comprised of extracellular collagen and proteoglycan macromolecules. Glycosaminoglycans (GAGs), the major constituents of proteoglycan molecules, were studied in mice infected with Schistosoma japonicum. Total GAG content was measured by extraction of uronic acid from murine liver sections and isolated hepatic granulomas during the progression from acute (0-15 wk) to chronic (20-30 wk) infection. Infected livers contained elevated levels of uronic acid throughout infection when compared to noninfected livers. Glycosaminoglycan content was found to peak at a value of 2.5 +/- 0.1 pmol/mg tissue (five times normal value) in acute infection (6-15 wk), a time of increasing hepatic fibrosis. Peak uronic acid content in isolated granulomas was also observed during acute infection with a maximal value of 7.1 +/- 0.9 pmol/mg tissue (9-11 wk). During chronic infection (30 wk), hepatic uronic acid content was reduced by 68% in unfractionated liver tissue and by 49% in isolated granulomas (both p less than 0.05). This modulation in GAG accumulation appeared to result from decreased biosynthesis, inasmuch as during chronic infection GAG biosynthetic rates fell by 42% in liver tissue and 53% in isolated granulomas (both p less than 0.05). In addition to these quantitative changes in GAG metabolism, GAG disaccharides were examined qualitatively by high-pressure liquid chromatography, which resolved nonsulfated, 6-sulfated, and 4-sulfated disaccharides. Few qualitative changes were seen in the GAG profile between normal liver and acutely or chronically infected liver. Both the rapid modulation of GAG accumulation despite ongoing infection and its qualitative makeup differentiate hepatic fibrosis seen in schistosomiasis japonica from that observed in many other forms of fibrotic liver disease.

Distal splenorenal shunt for management of variceal bleeding in patients with schistosomal hepatic fibrosis

The distal splenorenal shunt was performed in 60 patients with schistosomal hepatic fibrosis in whom no evidence of cirrhosis was documented by preoperative needle and operative wedge biopsy. No patients have been lost to follow-up with a median of 37 months (range: 17-86). The results showed low operative mortality (1.7%), high patency rate (92.5%), and low recurrent variceal hemorrhage (6.7%). Thrombosed shunts were treated either by refashioning the shunt (1 patient) or splenectomy and gastric devascularization (2 patients). Initial hyperbilirubinemia and reduction in serum albumin were found in the early postoperative period, with persistent hyperbilirubinemia in 32% of the patients. The 5-year survival was 88%, with liver disease related mortality in only three patients. Clinical encephalopathy was detected in three patients (5.1%); only one of them was incapacitated. These data showed that: selective shunt (distal splenorenal shunt, DSRS) is an effective surgical procedure in the treatment of schistosomal variceal bleeding, shunt thrombosis is rare and can possible be corrected if detected early, schistosomal patients have a better survival and a lower incidence of encephalopathy after DSRS than that reported in cirrhotics, and liver biopsy should be performed for proper assessment of the schistosomal population especially in the geographic areas where the schistosoma parasite and viral hepatitis are endemic.

The pathology of experimental Schistosoma curassoni infections in mice and hamsters

The histopathology of experimental Schistosoma curassoni infections in white mice and hamsters was studied. In mice, hepatic lesions were severe with characteristic extensive perilobular fibrosis and large perilobular granulomas throughout the parenchyma. Only a few granulomas were detected in the lung, small intestine, and rectum of mice. In hamsters, lesions in the liver were limited. Few granulomas were found but the giant cell reaction was pronounced. Lesions in the lung and small intestine were minimal. Many subserosal and submucosal epithelioid cell granulomas were in the colon and rectum of hamsters. Parasites were not detected in the bladder of either mice or hamsters.

A randomized trial for the study of the elective surgical treatment of portal hypertension in mansonic schistosomiasis

From 1977 to 1983, 94 patients with esophageal varices and gastrointestinal bleeding secondary to mansonic schistosomiasis were entered into a prospective randomized trial comparing the three operations mainly used in Brazil: esophagogastric devascularization associated with splenectomy (EGDS, 32 patients), classical splenorenal shunt (SRS, 32 patients), and distal splenorenal shunt (DSRS, 30 patients). The randomization was interrupted because of a significant incidence of portosystemic encephalopathy (PSE) in the SRS group (26%), as compared to the DSRS (7%) and EGDS (0%) groups. The rate of rebleeding was the same in the three groups, but the rate of failure, as defined by the presence of technical problems, postoperative complications, or death, was significantly higher in the SRS group. This 2-year follow-up shows that SRS should be abandoned in hepatosplenic schistosomiasis and that a comparison between DSRS and EGDS with a longer follow-up is urgently needed.

The pharmacokinetics of antipyrine in patients with graded severity of schistosomiasis

The pharmacokinetics of antipyrine have been studied in patients with schistosomiasis. In comparison to a control group of subjects (n = 6), patients with early (active) schistosomiasis (passing live ova in urine or stools without clinical and laboratory evidence of liver involvement; n = 6) exhibited similar pharmacokinetic parameters. Of seven patients with hepatosplenic schistosomiasis (exhibiting hepatic fibrosis, splenomegaly, at least one episode of haematemesis, ascites), five showed markedly enhanced antipyrine half-life and reduced clearance. Compared to controls, the mean half-life of this group was increased from 10.9 +/- 2.4 to 19.9 +/- 9.5 h (mean +/- s.d.; P less than or equal to 0.05) and clearance reduced from 3.81 +/- 0.74 to 2.18 +/- 0.80 l h-1 (P less than or equal to 0.01). There was no change in the apparent volume of distribution. Liver biopsy was performed on all patients diagnosed as having hepatosplenic schistosomiasis in the 2 weeks prior to the antipyrine study. The results of this study indicate that hepatic microsomal metabolism is impaired in patients with advanced hepatosplenic schistosomiasis.

Dynamics of collagen accumulation and polymorphism in murine Schistosoma japonicum

The dynamics of hepatic collagen biosynthesis and degradation were studied in mice infected with Schistosoma japonicum. Hepatic fibrosis, the major clinical manifestation of disease, increased during acute infection (0-15 wk). The majority of proline incorporation into hydroxyproline, which was reflective of collagen synthesis, was found within hepatic egg granulomas. As the disease became chronic (20-30 wk) there was a decrease in collagen synthesis and a maintenance of total collagenolytic activity, which resulted in decreased accumulations of both total hepatic and granuloma-associated collagen. In addition to these quantitative decreases in extracellular collagen there was a qualitative change in the type of hepatic collagen synthesized. Early in infection, type I collagen was the predominant biosynthetic product, whereas late in infection type III collagen became the dominant isotype. A similar switch was seen in the substrate specificity of the constitutive collagenolytic activity, with decreasing type I activity and increasing type III activity as the disease progressed from acute (10 wk) to chronic (30 wk). These changes in the quantity and makeup of extracellular collagen may lead to amelioration of disease and potential reversibility of fibrosis.

Basement membrane proteins and type III procollagen in murine schistosomiasis

The livers of female CBA mice were examined 9 to 10 weeks after subcutaneous infection with Schistosoma mansoni. Cryostat liver sections and isolated liver cells were examined by indirect immunofluorescence using specific antibodies against basement membrane proteins (laminin, fibronectin and type IV collagen and type III collagen precursor. Liver cells were isolated by collagenase digestion, purification on Percoll density gradients and centrifugal elutriation to yield enriched fractions of hepatocytes, endothelial and Kupffer cells (Fractions I, II, III respectively). Infected animals yielded more than three times the control number of non-parenchymal cells; electron microscopy revealed that the increase in Fraction II was due mainly to eosinophilic leucocytes and in Fraction III due to Kupffer cells and macrophages from the schistosomal granulomata. Studies of cryostat liver sections showed that the schistosomal granulomata contained dense deposits of type III collagen precursor and fibronectin in the distribution of the reticulin fibres but laminin and type IV collagen were conspicuous only in new vessels in the periphery of the granuloma. Isolated liver cells showed fibronectin on their surface. Immunofluorescence studies could not be performed on Kupffer and endothelial cell fractions because of marked non-specific fluorescence. These experiments indicate that centrifugal elutriation is a useful method for isolating the constituent cells of murine schistosomal granulomata.