Haemostatic abnormalities in hepatosplenic schistosomiasis mansoni

An overview of qualitative and quantitative platelet abnormalities in schistosomiasis

Schistosomiasis is a neglected tropical disease referring to the infection with blood parasitic trematodes of the genus Schistosoma. It impacts millions of people worldwide, primarily in low-to-middle-income countries. Patients infected with schistosomiasis often exhibit a distinct hematological profile, including anemia, eosinophilia, thrombocytopenia, and coagulopathy. Platelets, essential components of the hemostatic system, play a crucial role in the pathogenesis of schistosomiasis. Schistosomes secrete serine proteases and express ectoenzymes, such as calpain protease, alkaline phosphatase (SmAP), phosphodiesterase (SmNPP5), ATP diphosphohydrolase (SmATPDase1), serine protease Sk1, SmSP2, and Sm22.6, which can interfere with platelet normal functioning. This report provides comprehensive, up-to-date information on platelet abnormalities observed in patients with schistosomiasis, highlighting their importance in the disease progression and complications. It delves into the interactions between platelets and schistosomes, including the impact of platelet dysfunction on hemostasis and immune responses, immune-mediated platelet destruction, and the potential mechanisms by which schistosome tegumental ectoenzymes affect platelets. Furthermore, the report clarifies the relationship between platelet abnormalities and clinical manifestations such as thrombocytopenia, coagulation disorders, and the emergence of portal hypertension and gastrointestinal bleeding. Understanding the complex interplay between platelets and schistosomes is crucial for improving patient management and outcomes in schistosomiasis, particularly for those with platelet alterations. This knowledge contributes to improved diagnostic methods, innovative treatment strategies, and global efforts to control and eliminate schistosomiasis.

Status of selected biochemical and coagulation profiles and platelet count in malaria and malaria-Schistosoma mansoni co-infection among patients attending at Dembiya selected Health Institutions, Northwest Ethiopia

Malaria and schistosomiasis are infectious diseases that cause coagulation disorders, biochemical abnormalities, and thrombocytopenia. Malaria and Schistosoma mansoni co-infection cause exacerbations of health consequences and co-morbidities.This study aimed to compare the effect of malaria and Schistosoma mansoni co-infection and malaria infection on selected biochemical and coagulation profiles, and platelet count. An institutional-based comparative cross-sectional study was conducted from March 30 to August 10, 2022. A total of 70 individuals were enrolled in the study using a convenient sampling technique. Wet mount and Kato Katz techniques were conducted to detect Schistosoma mansoni in a stool sample. Blood films were prepared for the detection of plasmodium. The data was coded and entered into EpiData version 3.1 before being analyzed with SPSS version 25. An independent t test was used during data analysis. A P-value of less than 0.05 was considered statistically significant. The mean [SD] of alanine aminotransferase, aspartate aminotransferase, creatinine, total bilirubin, and direct bilirubin in the co-infected was higher than in malaria infected participants. However, the mean of total protein and glucose in co-infected was lower than in the malaria infected participants. The mean of prothrombin time, international normalization ratio, and activated partial thromboplastin time in co-infected was significantly higher, while the platelet count was lower compared to malaria infected participants. Biochemical and coagulation profiles, and platelet count status in co-infection were changed compared to malaria infected participants. Therefore, biochemical and coagulation profiles and platelet count tests should be used to monitor and manage co-infection related complications and to reduce co-infection associated morbidity and mortality.

Predicting the Occurrence of Advanced Schistosomiasis Based on FISHER Discriminant Analysis of Hematological Biomarkers

We established a model that predicts the possibility of chronic schistosomiasis (CS) patients developing into advanced schistosomiasis (AS) patients using special biomarkers that were detected in human peripheral blood. Blood biomarkers from two cohorts (132 CS cases and 139 AS cases) were examined and data were collected and analyzed by univariate and multivariate logistic regression analysis. Fisher discriminant analysis (FDA) for advanced schistosomiasis was established based on specific predictive diagnostic indicators and its accuracy was assessed using data of 109 CS. The results showed that seven indicators including HGB, MON, GLB, GGT, APTT, VIII, and Fbg match the model. The accuracy of the FDA was assessed by cross-validation, and 86.7% of the participants were correctly classified into AS and CS groups. Blood biomarker data from 109 CS patients were converted into the discriminant function to determine the possibility of occurrence of AS. The results demonstrated that the possibility of occurrence of AS and CS was 62.1% and 89.0%, respectively, and the accuracy of the established model was 81.4%. Evidence displayed that Fisher discriminant analysis is a reliable predictive model in the clinical field. It’s an important guide to effectively control the occurrence of AS and lay a solid foundation for achieving the goal of schistosomiasis elimination.

Hematological and Biochemical changes in Schistosoma mansoni infected patients at Haik Primary Hospital, North-East Ethiopia: A comparative cross-sectional study

Background

Schistosomes are blood dwelling parasites that affect more than 260 million people globally, and over 800 million people are at risk of infection in 74 countries. It causes acute and chronic debilitating diseases. The parasite is reported to alter the hematological and biochemical parameters in humans. Therefore, this study was aimed to evaluate the hematological and biochemical changes in S. mansoni infected adult patients compared to apparently healthy controls.

Methods

A comparative cross-sectional study was conducted at Haik Primary Hospital from February to April 2021. One hundred and eighty study participants consisting of 90 S. mansoni infected patients and 90 apparently healthy controls were recruited using systematic random sampling method. Socio-demographic characteristics and other variables were collected using questionnaires. Stool sample was examined microscopically to detect S. mansoni infection using direct wet mount and Kato Katz technique. In apparently healthy controls, S. mansoni infection was rule out using direct wet mount and Kato Katz technique. Moreover, the intensity of S. mansoni infection was assessed using Kato Katz technique. Blood sample was collected from each study participant to determine the hematological and biochemical profiles. Data were entered in to Epi Data version 3.1 and analyzed using SPSS version 26.0 software. Kolmogorov-Smirnov and Shapiro Wilk normality tests were done to assess the distribution of continuous variables. The Mann-Whitney U test and Kruskal Wallis H test was done to compare the differences among nonnormally distributed variables between S. mansoni infected patients and healthy controls. P-values <0.05 at 95%CI were considered as statistically significant.

Result

The mean age (SD) of S. mansoni infected patients and apparently healthy controls was 30.33 (±12.26) and 31.2 (±12.85) years old, respectively. The prevalence of anemia, and thrombocytopenia among S. mansoni infected patients were 23.3% and 26.7%, respectively. Erythrocytic sedimentation rate (ESR) was significantly elevated among S. mansoni infected patients than apparently healthy controls. The median white blood cell count, red blood cell count, red blood cell indices, and platelet indices were significantly lower among S. mansoni infected patients compared to apparently healthy controls (P<0.05). On the other hand, the median eosinophil count was significantly elevated among S. mansoni infected patients compared to apparently healthy controls (P<0.05). This study also showed significantly elevated values of serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and direct bilirubin and lower albumin, total cholesterol and triglycerides among S. mansoni infected patients compared to apparently healthy controls. Kruskal Wallis H test showed a significant difference in the median of most hematological and biochemical parameters between moderate and heavy intensity of infection with light intensity of infection and apparently healthy controls.

Conclusion

The findings of this study showed significantly altered hematological values and liver function tests among S. mansoni infected patients compared to apparently healthy controls. Therefore, screening of S. mansoni infected patients for various hematological and biochemical parameters and providing treatment to the underlying abnormalities is very crucial to avoid schistosomiasis associated morbidity and mortality.

A Comparative Cross-Sectional Study of Coagulation Profiles and Platelet Parameters of Schistosoma mansoni-Infected Adults at Haik Primary Hospital, Northeast Ethiopia

Introduction. Schistosoma mansoni is an intravascular parasite that interacts with all components of the host blood. Nearly, 10% of S. mansoni-infected patients progress to severe hepatosplenic Schistosomiasis is characterized by periportal fibrosis, obstruction of intrahepatic veins, presinusoidal portal hypertension, and splenomegaly. Thus, this study aimed to compare the basic coagulation profiles and platelet parameters of S. mansoni-infected adults and noninfected individuals as controls at Haik Primary Hospital, Northeast Ethiopia. Methods. A comparative cross-sectional study was conducted at Haik Primary Hospital from April to June 2021. The diagnosis and intensity of S. mansoni infection was determined using the Kato–Katz technique. The coagulation profiles and platelet parameters were analyzed using coagulation and hematology analyzers. Data were analyzed using SPSS version 26.0. The Kolmogorov–Smirnov and Shapiro–Wilk tests were done to check the distribution of continuous variables. The Mann–Whitney U test was used to compare the coagulation profiles and platelet parameters. Spearman’s rank-order correlation was done to assess the correlation between the intensity of infection and coagulation profiles and platelet parameters. In all comparison, a $P$ value <0.05 was considered statistically significant. Result. In this study, a total of 180 study participants (90 S. mansoni-infected adults and 90 controls) were included. Of the total S. mansoni-infected adults, 55.6%, 28.9%, 33, and 15.6% had light, moderate, and heavy intensity of infections, respectively. All S. mansoni-infected study participants had prolonged prothrombin time (PT) and international normalized ratio (INR). Moreover, about 80% of S. mansoni-infected adults had prolonged activated partial thromboplastin time (APTT). Thrombocytopenia was found in 26.7% of the S. mansoni-infected adults. The Mann–Whitney U test showed a statistically significant difference in coagulation profiles between S. mansoni-infected adults and healthy controls ( $P$ -value ≤0.001). The Kruskal–Wallis H-test showed a significant difference in PT, APTT, and INR between the intensity of infection and healthy controls ( $P$ -value <0.05). Conclusion. This study showed a prolonged coagulation time in S. mansoni-infected individuals. Thus, screening of schistosomiasis patients for hemostatic abnormalities and treating the underlying disorder is crucial.

Machine learning algorithms to predict the 1 year unfavourable prognosis for advanced schistosomiasis

Short-term prognosis of advanced schistosomiasis has not been well studied. We aimed to construct prognostic models using machine learning algorithms and to identify the most important predictors by utilising routinely available data under the government medical assistance programme. An established database of advanced schistosomiasis in Hunan, China was utilised for analysis. A total of 9541 patients for the period from January 2008 to December 2018 were enrolled in this study. Candidate predictors were selected from demographics, clinical features, medical examinations and test results. We applied five machine learning algorithms to construct 1 year prognostic models: logistic regression (LR), decision tree (DT), random forest (RF), artificial neural network (ANN) and extreme gradient boosting (XGBoost). An area under the receiver operating characteristic curve (AUC) was used to evaluate the model performance. The important predictors of the optimal model for unfavourable prognosis within 1 year were identified and ranked. There were 1249 (13.1%) cases having unfavourable prognoses within 1 year of discharge. The mean age of all participants was 61.94 years, of whom 70.9% were male. In general, XGBoost showed the best predictive performance with the highest AUC (0.846; 95% confidence interval (CI): 0.821, 0.871), compared with LR (0.798; 95% CI: 0.770, 0.827), DT (0.766; 95% CI: 0.733, 0.800), RF (0.823; 95% CI: 0.796, 0.851), and ANN (0.806; 95% CI: 0.778, 0.835). Five most important predictors identified by XGBoost were ascitic fluid volume, haemoglobin (HB), total bilirubin (TB), albumin (ALB), and platelets (PT). We proposed XGBoost as the best algorithm for the evaluation of a 1 year prognosis of advanced schistosomiasis. It is considered to be a simple and useful tool for the short-term prediction of an unfavourable prognosis for advanced schistosomiasis in clinical settings.

Schistosoma mansoni infection affects the proteome and lipidome of circulating extracellular vesicles in the host

Eggs, schistosomula and adult Schistosoma worms are known to release extracellular vesicles (EV) during in vitro incubations and these EVs are postulated to affect the host responses. So far only those EVs released during in vitro incubations of schistosomes have been studied and it is unknown whether in blood of infected hosts the schistosomal EVs can be detected amidst all the circulating EVs of the host itself. In this study we analyzed the protein as well as the phospholipid composition of EVs circulating in blood plasma of S. mansoni infected hamsters and compared those with the EVs circulating in blood of non-infected hamsters. Although neither proteins nor lipids specific for schistosomes could be detected in the circulating EVs of the infected hamsters, the infection with schistosomes had a marked effect on the circulating EVs of the host, as the protein as well as the lipid composition of EVs circulating in infected hamsters were different from the EVs of uninfected hamsters. The observed changes in the EV lipid and protein content suggest that more EVs are released by the diseased liver, the affected erythrocytes and activated immune cells.

Basic Coagulation Profiles and Platelet Count Among Schistosoma mansoni-Infected Adults Attending Sanja Primary Hospital, Northwest Ethiopia

PURPOSE

To assess basic coagulation profiles and platelet count among Schistosoma mansoni-infected and non-infected adults.

PATIENTS AND METHODS

A comparative cross-sectional study was conducted from February to April 2019 at Sanja Primary Hospital, northwest Ethiopia. A total of 200 adults (100 cases and 100 controls) were enrolled using convenient sampling technique. Both wet mount and Kato-Katz techniques were performed using a stool sample. The venous blood sample was collected to perform platelet count, basic coagulation and serological tests. The data were coded and entered into EpiData Manager (v4.4.2.1) and analyzed using SPSS version 20. Nonparametric tests were used during data analysis. P-value less than 0.05 was considered as statistically significant.

RESULTS

Prothrombin time (PT), activated partial thromboplastin time (APTT) and international normalization ratio (INR) were significantly higher while the platelet count was significantly lower in S. mansoni-infected than healthy adults (P <0.001). There were statistically significant differences in the median [IQR] value of PT, APTT, INR and platelet count between light, moderate and heavy infected groups (P <0.05). Infection intensity had a positive correlation with basic coagulation profiles and a negative correlation with platelet count (P <0.05) of S. mansoni-infected adults.

CONCLUSION

The prevalence of coagulation abnormality was higher in S. mansoni-infected adults than healthy controls. Coagulation test and platelet count should be used to monitor and manage schistosomiasis-related complications.

Haemostatic changes in urogenital schistosomiasis haematobium: a case-control study in Gabonese schoolchildren

In many tropical areas schistosomiasis is a major health problem causing hepatosplenic, intestinal or urogenital complaints. Hepatosplenic schistosomiasis mansoni is also characterized by blood coagulation abnormalities. Liver pathology plays a role in the development of haemostatic changes and the parasitic infection may directly affect coagulation. However, these contributing factors cannot be studied separately in hepatosplenic schistosomiasis infections. This pilot study provides insight in haemostatic changes in urinary schistosomiasis by studying coagulation parameters in schistosomiasis haematobium-infected Gabonese schoolchildren. Selection on urinary schistosomiasis patients without hepatosplenic complaints allows for the investigation of the direct effects of the parasite on haemostasis. Levels of von Willebrand Factor (VWF) antigen, active VWF and osteoprotegerin were elevated, indicating inflammation-mediated endothelial activation. In contrast to hepatosplenic schistosomiasis, thrombin-antithrombin complex and D-dimer levels were not affected. Despite its small sample size, this study clearly indicates that Schistosoma haematobium directly alters the activation status of the endothelium, without initiation of coagulation.

Alterations in the lipid profiles and circulating liver enzymes in individuals infected by Schistosoma mansoni

INTRODUCTION

Portal hypertension and periportal fibrosis commonly occur in severe Schistosoma mansoni infection. Changes in lipid profile and elevated levels of circulating liver enzymes have also been described in infected individuals. The present study sought to assess the alterations in laboratory parameters associated with liver disorder in individuals infected by S. mansoni who visited a private routine laboratory service. Levels of circulating liver enzymes (gamma-glutamyl transferase [γ-GT], aspartate transaminase [AST], alanine transaminase [ALT], and alkaline phosphatase [ALP]) and a lipid panel (total cholesterol [COL], high-density lipoprotein [HDL], low-density lipoprotein [LDL], very low-density lipoprotein [VLDL], and triglycerides [TRI]) were evaluated in both infected and non-infected individuals and relative risk was used to measure associations.

METHODS

Data were collected for analysis from a total of 1,078 cases identified in 379,600 individuals who submitted samples to the Datalab Laboratory (Salvador, Bahia) between 2004 and 2008.

RESULTS

S. mansoni infection led to increased circulating levels of γ-GT in both women and men, AST (women), and ALP (men). S. mansoni infection was a protective factor against increased levels of TRI, CHO, and VLDL for individuals aged 19 years or older. The results of our analysis indicate that alterations in lipid metabolism and circulating liver enzymes in asymptomatic S. mansoni-infected individuals might be attributed to eggs lodged in the hepatic sinusoids.

CONCLUSIONS

Parasitological testing for S. mansoni should be indicated in endemic areas when this pattern of alterations is detected.

The blood fluke Schistosoma mansoni cleaves the coagulation protein high molecular weight kininogen (HK) but does not generate the vasodilator bradykinin

Background

Schistosomes are blood dwelling parasitic worms that cause the debilitating disease schistosomiasis. Here we examined the influence of the parasites on their external environment by monitoring the impact of adult Schistosoma mansoni worms on the murine plasma proteome in vitro and, in particular, on how the worms affect the blood coagulation protein high molecular weight kininogen (HK).

Methods

Following the incubation of adult schistosomes in murine plasma, two-dimensional differential in-gel electrophoresis (2D-DIGE) was conducted to look for changes in the plasma proteome compared with control plasma. A major change to the blood protein kininogen (HK) was observed, and the interaction of Schistosoma mansoni parasite with this protein alone was then investigated by western blot analysis and activity assays. Finally, the generation of bradykinin from HK was monitored using a bradykinin detection kit.

Results

The most striking change to the plasma proteome concerned HK; while the full-length protein was more abundant in control plasma, carboxyl-terminal truncated forms were more abundant in plasma that contained schistosomes. Incubating parasites in buffer with pure HK followed by Western blot analysis confirmed that human HK is degraded by the worms. The resulting digestion pattern differed from that brought about by kallikrein, a host serine protease that normally acts on HK to release the vasodilator bradykinin. We found that live schistosomes, while digesting HK, do not generate bradykinin nor do they cleave a chromogenic kallikrein substrate. Since the cleavage of HK by the worms is not impeded by the serine protease inhibitor PMSF but is blocked by the cysteine protease inhibitor E64c, we hypothesize that schistosome tegumental cysteine proteases are responsible for HK cleavage.

Conclusions

Since proteomic and biochemical studies have revealed that the schistosome tegument contains two cysteine proteases belonging to the calpain family (SmCalp1 and SmCalp2) we conclude that these are likely responsible for the HK cleavage reported here. Schistosome cleavage of HK should help impede blood clotting and inflammation around the worms in vivo and so promote their ease of movement within the vasculature of their hosts.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-2704-0) contains supplementary material, which is available to authorized users.

Therapeutic potential of helminths in autoimmune diseases: helminth-derived immune-regulators and immune balance

Helminths have accompanied human throughout history by releasing immune-evasion molecules that could counteract an aberrant immune response within the host. In the past decades, helminth infections are becoming less prevalent possibly due to the developed sanitation. Meanwhile, the incidence of autoimmune diseases is increasing, which cannot be exclusively explained by the changes of susceptibility genes. While the hygiene hypothesis casts light on the problem. The infections of helminths are believed to interact with and regulate human immunity with the byproduct of suppressing the autoimmune diseases. Thus, helminths are potential to treat or cure the autoimmune diseases. The therapeutic progresses and possible immune suppression mechanisms are illustrated in the review. The helminths that are studied most intensively include Heligmosomoides polygyrus, Hymenolepis diminuta, Schistosoma mansoni, Trichinella spiralis, and Trichuris suis. Special attentions are paid on the booming animal models and clinical trials that are to detect the efficiency of immune-modulating helminth-derived molecules on autoimmune diseases. These trials provide us with a prosperous clinical perspective, but the precise mechanism of the down-regulatory immune response remains to be clarified. More efforts are needed to be dedicated until these parasite-derived immune modulators could be used in clinic to treat or cure the autoimmune diseases under a standard management.

A case control study on the structural equation model of the mechanism of coagulation and fibrinolysis imbalance in chronic schistosomiasis

A structural equation model was used for verification with chronic schistosomiasis to investigate the coagulation-anticoagulation system imbalance and to deduce the mechanism of D-dimer (D-D) level elevation in patients with advanced schistosome hepatic disease. We detected the plasma levels of tissue-type fiber plasminogen activator (tPA), urokinase type plasminogen activator (uPA), plasmin-antiplasmin complex (PAP), plasminogen (PLG), antithrombin (AT), plasminogen activator inhibitor 1 (PAI1), D-D, factor VIII: C (FVIII:C), antithrombin-III (AT-III), PLG, protein S (PS), and protein C (PC) in the healthy people as control (69), patients with chronic schistosomiasis (150) or advanced chronic schistosomiasis (90). FVIII, PAP, D-D, tPA, and uPA plasma levels were significantly higher in the chronic group than in the control group and were also significantly higher in the advanced group. However, AT-III, PC, PS, AT, PLG, and PAI1 plasma levels in the advanced and chronic groups were significantly lower than those in the control group. With progression of disease in patients with schistosomiasis japonica, a hypercoagulable state is induced by the coagulation-anticoagulation imbalance, eventually leading to patients with high levels of D-D. Furthermore, we established a structural equation model path of a "chronic schistosomiasis disease stage-(coagulation-anticoagulation-fibrinolysis)-D-D." By using analysis of moment structures (AMOS), it was shown that the chronic schistosomiasis stage was positively related to factor VIII and had negative correlation with AT-III; a good positive correlation with PAP, tPA, and uPA; and a good negative correlation with PLG and PAI1. In addition, our results show that the path coefficient of anticoagulation-fibrinolysis system to the chronic stage of schistosomiasis or D-D levels was significantly higher than that of the coagulation system. In conclusion, the coagulation and fibrinolysis imbalance in patients with chronic schistosomiasis, especially with advanced schistosomiasis, is due to the progression of disease stages.

Schistosoma bovis-host interplay: Proteomics for knowing and acting

Schistosoma bovis is a parasite of ruminants that causes significant economic losses to farmers throughout Africa, Southwestern Asia and the Mediterranean. Additionally, recent studies have reported its zoonotic potential through the formation of S. bovis×Schistosoma haematobium hybrids. As observed in the Schistosoma species infecting humans, it is assumed that S. bovis has also evolved host regulatory molecules that ensure its long-term survival in the bloodstream of its host. Since these molecules could be potential targets for the development of new drugs and anti-schistosome vaccines, their identification and functional characterization were undertaken. With this aim in mind, the molecular interface between S. bovis and its vertebrate host was subjected to a series of proteomic studies, which started with the analysis of the proteomes of the S. bovis moieties exposed to the host, namely, the excretory/secretory products and the tegument surface. Thus, a wealth of novel molecular information of S. bovis was obtained, which in turn allowed the identification of several parasite proteins with fibrinolytic and anticoagulant activities that could be used by S. bovis to regulate the host defensive systems. Following on, the host interface was investigated by studying the proteome of the host vascular endothelium surface at two points along the infection: in the lung vessels during the schistosomula migration and in the portal vein after the parasites have reached adulthood and sexual maturity. These studies have provided original data regarding the proteomes of the endothelial cell surface of pulmonary vasculature and portal vein in S. bovis-infected animals, and have shown significant changes in these proteomes associated with infection. This review compiles current information and the analyses of all the proteomic data from S. bovis and the S. bovis-host interface, including the molecular and functional characterization of S. bovis proteins that were found to participate in the regulation of the host coagulation and fibrinolysis systems.

Relationship between splenomegaly and hematologic findings in patients with hepatosplenic schistosomiasis

Background

Schistosomiasis is a tropical disease. Patients who develop hepatosplenic schistosomiasis have clinical findings including periportal fibrosis, portal hypertension, cytopenia, splenomegaly and gastrointestinal hemorrhage.

Objective

The aim of this study was to analyze the hemostatic and hematologic findings of patients with schistosomiasis and correlate these to the size of the spleen.

Methods

Fifty-five adults with hepatosplenic schistosomiasis and 30 healthy subjects were selected through a history of contact with contaminated water, physical examination and ultrasound characteristics such as periportal fibrosis and splenomegaly in the Gastroenterology Service of the Universidade Federal de Pernambuco. Blood samples were collected to determine liver function, blood counts, prothrombin (international normalized ratio), partial thromboplastin time and fibrinogen and D-Dimer levels using the Pentra 120 hematological analyzer (HORIBA/ABX), Density Plus (test photo-optical Trinity Biotech, Ireland) and COBAS analyzer 6000 (Roche). Furthermore, the longitudinal size of the spleen was measured by ultrasound (Acuson X analyzer 150, Siemens). The Student t-test, the Fisher test and Pearson's correlation were used to analyze the results with statistical significance being set for a p-value < 0.05.

Results

The mean age was higher for the Study Group than for the Control Group (54 ± 13.9 vs. 38 ± 12.7 years). The average longitudinal diameter of the spleen was 16.9 cm (Range: 12.3-26.3 cm). Anemia is a common finding in patients with schistosomiasis (36.3%). The mean platelet and leukocyte counts of patients were lower than for the Control Group (p-value < 0.001). Moreover, the international normalized ratio (1.42 vs. 1.04), partial thromboplastin time (37.9 vs. 30.5 seconds) and D-Dimer concentration (393 vs. 86.5 ng/mL) were higher for the Study Group compared to the Control Group.

Conclusion

This study suggests that hematological and hemostatic abnormalities are associated with splenomegaly, hypersplenism and portal hypertension.

A novel coagulation inhibitor from Schistosoma japonicum

Little is known about the molecular mechanisms whereby the human blood fluke Schistosoma japonicum is able to survive in the host venous blood system. Protease inhibitors are likely released by the parasite enabling it to avoid attack by host proteolytic enzymes and coagulation factors. Interrogation of the S. japonicum genomic sequence identified a gene, SjKI-1, homologous to that encoding a single domain Kunitz protein (Sjp_0020270) which we expressed in recombinant form in Escherichia coli and purified. SjKI-1 is highly transcribed in adult worms and eggs but its expression was very low in cercariae and schistosomula. In situ immunolocalization with anti-SjKI-1 rabbit antibodies showed the protein was present in eggs trapped in the infected mouse intestinal wall. In functional assays, SjKI-1 inhibited trypsin in the picomolar range and chymotrypsin, neutrophil elastase, FXa and plasma kallikrein in the nanomolar range. Furthermore, SjKI-1, at a concentration of 7·5 µ m, prolonged 2-fold activated partial thromboplastin time of human blood coagulation. We also demonstrate that SjKI-1 has the ability to bind Ca(++). We present, therefore, characterization of the first Kunitz protein from S. japonicum which we show has an anti-coagulant properties. In addition, its inhibition of neutrophil elastase indicates SjKI-1 have an anti-inflammatory role. Having anti-thrombotic properties, SjKI-1 may point the way towards novel treatment for hemostatic disorders.

Splenectomy Improves Hemostatic and Liver Functions in Hepatosplenic Schistosomiasis Mansoni

BACKGROUND

Schistosomiasis mansoni is a chronic liver disease, in which some patients (5-10%) progress to the most severe form, hepatosplenic schistosomiasis. This form is associated with portal hypertension and splenomegaly, and often episodes of gastrointestinal bleeding, even with liver function preserved. Splenectomy is a validated procedure to reduce portal hypertension following digestive bleeding. Here, we evaluate beneficial effects of splenectomy on blood coagulation factors and liver function tests in hepatosplenic schistosomiasis mansoni compared to non-operated patients.

METHODOLOGY/PRINCIPAL FINDINGS

Forty-five patients who had undergone splenectomy surgery were assessed by laboratory analyses and ultrasound examination and compared to a non-operated group (n = 55). Blood samples were obtained for liver function tests, platelet count and prothrombin time. Coagulation factors (II, VII, VIII, IX and X), protein C and antithrombin IIa, plasminogen activator inhibitor-1 were measured by routine photometric, chromogenic or enzyme-linked immunosorbent assays, while hyperfibrinolysis was defined by plasminogen activator inhibitor-1 levels. Both groups had similar age, gender and pattern of periportal fibrosis. Splenectomized patients showed significant reductions in portal vein diameter, alkaline phosphatase and bilirubin levels compared to non-operated patients, while for coagulation factors there were significant improvement in prothrombin, partial thromboplastin times and higher levels of factor VII, VIII, IX, X, protein C and plasminogen activator inhibitor-1.

CONCLUSION/SIGNIFICANCE

This study shows that the decrease of flow pressure in portal circulation after splenectomy restores the capacity of hepatocyte synthesis, especially on the factor VII and protein C levels, and these findings suggest that portal hypertension in patients with hepatosplenic schistosomiasis influences liver functioning and the blood coagulation status.

Interference with the host haemostatic system by schistosomes

Schistosomes, parasitic flatworms that cause the tropical disease schistosomiasis, are still a threat. They are responsible for 200 million infections worldwide and an estimated 280,000 deaths annually in sub-Saharan Africa alone. The adult parasites reside as pairs in the mesenteric or perivesicular veins of their human host, where they can survive for up to 30 years. The parasite is a potential activator of blood coagulation according to Virchow's triad, because it is expected to alter blood flow and endothelial function, leading to hypercoagulability. In contrast, hepatosplenic schistosomiasis patients are in a hypocoagulable and hyperfibrinolytic state, indicating that schistosomes interfere with the haemostatic system of their host. In this review, the interactions of schistosomes with primary haemostasis, secondary haemostasis, fibrinolysis, and the vascular tone will be discussed to provide insight into the reduction in coagulation observed in schistosomiasis patients.

Interference with the haemostatic system by pathogens is a common mechanism and has been described for other parasitic worms, bacteria, and fungi as a mechanism to support survival and spread or enhance virulence. Insight into the mechanisms used by schistosomes to interfere with the haemostatic system will provide important insight into the maintenance of the parasitic life cycle within the host. This knowledge may reveal new potential anti-schistosome drug and vaccine targets. In addition, some of the survival mechanisms employed by schistosomes might be used by other pathogens, and therefore, these mechanisms that interfere with host haemostasis might be a broad target for drug development against blood-dwelling pathogens. Also, schistosome antithrombotic or thrombolytic molecules could form potential new drugs in the treatment of haemostatic disorders.

Hemostatic dysfunction is increased in patients with hepatosplenic schistosomiasis mansoni and advanced periportal fibrosis

BACKGROUND

Schistosomiasis mansoni is an endemic parasitic disease and a public health problem in Northeast Brazil. In some patients, hepatic abnormalities lead to periportal fibrosis and result in the most severe clinical form, hepatosplenic schistosomiasis. This study aimed to evaluate whether abnormal blood coagulation and liver function tests in patients with hepatosplenic schistosomiasis (n = 55) correlate with the severity of their periportal fibrosis.

METHODOLOGY/PRINCIPAL FINDINGS

Blood samples were used for liver function tests, hemogram and prothrombin time (International Normalized Ratio, INR). The blood coagulation factors (II, VII, VIII, IX and X), protein C and antithrombin IIa (ATIIa), plasminogen activator inhibitor 1 (PAI-1) and D-dimer were measured by photometry or enzyme linked immunosorbent assay. Hyperfibrinolysis was defined on the basis of PAI-1 levels and a D-dimer concentration greater than a standard cut-off of 483 ng/mL. Standard liver function tests were all abnormal in the patient group compared to healthy controls (n = 29), including raised serum transaminases (p<0.001) and lower levels of albumin (p = 0.0156). Platelet counts were 50% lower in patients, while for coagulation factors there was a 40% increase in the INR (p<0.001) and reduced levels of Factor VII and protein C in patients compared to the controls (both p<0.001). Additionally, patients with more advanced fibrosis (n = 38) had lower levels of protein C compared to those with only central fibrosis (p = 0.0124). The concentration of plasma PAI-1 in patients was one-third that of the control group (p<0.001), and D-dimer levels 2.2 times higher (p<0.001) with 13 of the 55 patients having levels above the cut-off.

CONCLUSION/SIGNIFICANCE

This study confirms that hemostatic abnormalities are associated with reduced liver function and increased liver fibrosis. Of note was the finding that a quarter of patients with hepatosplenic schistosomiasis and advanced periportal fibrosis have hyperfibrinolysis, as judged by excessive levels of D-dimer, which may predispose them to gastrointestinal bleeding.

Use of the platelet count/spleen diameter ratio for the noninvasive diagnosis of esophageal varices in patients with schistosomiasis

BACKGROUND/AIM

In patients with liver cirrhosis, the platelet count/spleen diameter ratio has been validated as a parameter for the noninvasive diagnosis of esophageal varices. Schistosoma infection is a frequent cause of portal hypertension in Middle Eastern countries, and is associated with the development of esophageal varices. In this study we aimed to evaluate the platelet count/spleen diameter ratio as a noninvasive tool for the prediction of the presence of esophageal varices in patients with schistosoma-related chronic liver disease.

PATIENTS AND METHODS

Forty-three patients with hepatosplenic schistosomiasis underwent upper digestive endoscopy to check for the presence of esophageal varices. Furthermore, all patients underwent abdominal ultrasonography, and maximum spleen diameter (in mm) was measured. The platelet count/spleen diameter ratio was calculated in all patients.

RESULTS

Esophageal varices were found in 31 patients (72%). Age and gender were not significantly different between patients with and without varices. In patients with varices, median platelet count (82,000/μL versus 172,000/μL, P < 0.0001) and platelet count/spleen diameter ratio (571 versus 1651, P < 0.0001) were significantly lower, while spleen diameter (147 mm versus 109 mm, P = 0.0006) was significantly larger. In multivariate analysis, the platelet count/spleen diameter ratio was the only parameter independently associated with the presence of varices (P < 0.0001).

CONCLUSIONS

In this study we have validated the use of the platelet count/spleen diameter ratio for the noninvasive diagnosis of esophageal varices in patients with portal hypertension caused by schistosoma infection. In these patients, the platelet count/spleen diameter ratio might be used to allow better rationalization of medical resources and use of endoscopy.

Eosinophilia and thrombosis in parasitic diseases: an overview

It is known that peripheral blood eosinophilia (PBE) is a normal hematopoietic response to several parasitic diseases, but it is less known that PBE promotes a hypercoagulable state that may favor thrombosis. Scope of this article is to explore which parasitic infestations are most likely to be complicated by thrombosis and to highlight the pathogenetic contribution of PBE to vascular occlusions in this setting. A review of the world literature revealed 18 cases in which PBE was associated with vascular occlusion though no specific surveys were dedicated to this topic. The eosinophil exerts its thrombogenic potential by inhibition of the natural anticoagulant pathways and release of tissue factor with enhanced coagulation activation leading to vascular occlusion. It is hoped that this review contributes to the awareness of the link between PBE and thrombosis in parasitic disorders to foster research in this area.

Immunology of human schistosomiasis: off the beaten path

Reviews of the immunology of human schistosomiasis generally address the host's protective responses against infection or the factors associated with development of severe pathology. However, there is a growing recognition that the high number of patients expressing moderate morbidity, rather than the few patients with severe morbidity, accounts for the greatest public health impact of schistosomiasis. Therefore, other aspects of the host immune response that have received relatively little attention may actually provide pivotal answers in our understanding and management of the morbidity associated with human schistosomiasis. This review highlights lines of investigation that focus on how immune responses to schistosomiasis may affect schistosomiasis-associated anaemia, alter susceptibility or disease progression during co-infections, and influence effective execution of mass treatment programmes.