The Dynamics of Hepatic Fibrosis Related to Schistosomiasis and Its Risk Factors in a Cohort of China

Feasibility of ultrasound radiomics based models for classification of liver fibrosis due to Schistosoma japonicum infection

BACKGROUND

Schistosomiasis japonica represents a significant public health concern in South Asia. There is an urgent need to optimize existing schistosomiasis diagnostic techniques. This study aims to develop models for the different stages of liver fibrosis caused by Schistosoma infection utilizing ultrasound radiomics and machine learning techniques.

METHODS

From 2018 to 2022, we retrospectively collected data on 1,531 patients and 5,671 B-mode ultrasound images from the Second People's Hospital of Duchang City, Jiangxi Province, China. The datasets were screened based on inclusion and exclusion criteria suitable for radiomics models. Liver fibrosis due to Schistosoma infection (LFSI) was categorized into four stages: grade 0, grade 1, grade 2, and grade 3. The data were divided into six binary classification problems, such as group 1 (grade 0 vs. grade 1) and group 2 (grade 0 vs. grade 2). Key radiomic features were extracted using Pyradiomics, the Mann-Whitney U test, and the Least Absolute Shrinkage and Selection Operator (LASSO). Machine learning models were constructed using Support Vector Machine (SVM), and the contribution of different features in the model was described by applying Shapley Additive Explanations (SHAP).

RESULTS

This study ultimately included 1,388 patients and their corresponding images. A total of 851 radiomics features were extracted for each binary classification problems. Following feature selection, 18 to 76 features were retained from each groups. The area under the receiver operating characteristic curve (AUC) for the validation cohorts was 0.834 (95% CI: 0.779-0.885) for the LFSI grade 0 vs. LFSI grade 1, 0.771 (95% CI: 0.713-0.835) for LFSI grade 1 vs. LFSI grade 2, and 0.830 (95% CI: 0.762-0.885) for LFSI grade 2 vs. LFSI grade 3.

CONCLUSION

Machine learning models based on ultrasound radiomics are feasible for classifying different stages of liver fibrosis caused by Schistosoma infection.

Characteristics of peripheral lymphocyte subsets in patients with different stages of schistosomiasis japonica

Immune cells are important for the development of schistosomiasis japonica and are also critical for the treatment of schistosomiasis. The immune cells in the peripheral blood help assess the immune state. The peripheral lymphocytes in schistosomiasis mansoni were well studied; however, immune cells in patients with different stages of schistosomiasis japonica are not well analysed. Here, we performed a preliminary study to explore characteristics of peripheral lymphocyte subsets in patients with different stages of schistosomiasis japonica. 135 patients with Schistosoma japonicum infection and 25 healthy volunteers were included in this study, including 84 patients with chronic S. japonicum infection and 51 patients with advanced S. japonicum infection. Flow cytometry analysis was performed to evaluate peripheral lymphocytes including T cells, B cells, and natural killer (NK) cells. Blood routine and liver function test data were analysed. Ultrasound examination was used to access liver fibrosis according to the World Health Organization standard about ultrasound in schistosomiasis. Demographic data analysis suggested there was no difference in age and gender in patients with S. japonicum infection and health control group. Liver function tests showed that patients with advanced schistosomiasis had a higher incidence of liver function abnormality and blood lipid than those with chronic schistosomiasis. Blood routine results reflected that haemoglobin, red blood cells, platelets, as well as lymphocytes in the advanced group were significantly less than that in the chronic group. Furthermore, flow cytometry analysis indicated that the percentage of CD4+ T cells was lower in the advanced group, but the percentage of CD19+ B cells was higher in the advanced group. In addition, the number of CD3+ T cells, CD3+ CD4+ T cells, CD3+ CD8+ T cells, and NK cells was less in the advanced group when compared with those in the chronic group. In addition, there was a correlation between the decrease in CD4+ T cells and more severe fibrosis on ultrasound images. Our results indicated that the immune state in the peripheral is different in different stages of S. japonicum infection. Lymphocyte subset analysis has potential to facilitate differential diagnosis of different stages of schistosomiasis japonica and even to be a prognostic factor.

IgG persistence showed weak clinical aspects in chronic schistosomiasis patients

Schistosomiasis is a chronic parasitic disease, which affects the quality of daily life of patients and imposes a huge burden on society. Hepatic fibrosis in response to continuous insult of eggs to the liver is a significant cause of morbidity and mortality. However, the mechanisms of hepatic fibrosis in schistosomiasis are largely undefined. The purpose of our study is to detect the indicator to hepatic fibrosis in schistosomiasis. A total of 488 patients with chronic schistosomiasis japonica were enrolled in our study. The patients were divided into two groups according to liver ultrasound examination, which could indicate liver fibrosis of schistosomiasis with unique reticular changes. Logistic regression analysis showed that globulin, albumin/globulin, GGT levels and anti-Schistosoma IgG were independently associated with liver fibrosis in patients with schistosomiasis and IgG was the largest association of liver fibrosis (OR  2.039, 95% CI 1.293-3.213). We further compared IgG+ patients with IgG- patients. IgG+ patients (ALT 25 U/L, GGT 31 U/L) slightly higher than IgG- patients (ALT 22 U/L, GGT 26 U/L) in ALT and GGT. However, the fibrosis of liver in IgG+ patients (Grade II(19.7%), Grade III(7.3%)) were more severe than that in IgG- patients(Grade II(12.5%), Grade III(2.9%)) according to the grade of liver ultrasonography. Our results showed anti-Schistosoma IgG was independently associated with liver fibrosis in patients with chronic schistosomiasis japonica and patients with persistent anti-Schistosoma IgG might have more liver fibrosis than negative patients despite no obvious clinical signs or symptoms.

Inhibition of hepatic natural killer cell function via the TIGIT receptor in schistosomiasis-induced liver fibrosis

Schistosomiasis is a zoonotic parasitic disease. Schistosoma japonicum eggs deposited in the liver tissue induce egg granuloma formation and liver fibrosis, seriously threatening human health. Natural killer (NK) cells kill activated hepatic stellate cells (HSCs) or induce HSC apoptosis and inhibit the progression of liver fibrosis. However, the function of NK cells in liver fibrosis caused by S. japonicum infection is significantly inhibited. The mechanism of this inhibition remains unclear. Twenty mice were percutaneously infected with S. japonicum cercariae. Before infection and 2, 4, 6, and 8 weeks after infection, five mice were euthanized and dissected at each time point. Hepatic NK cells were isolated and transcriptome sequenced. The sequencing results showed that Tigit expression was high at 4-6 weeks post infection. This phenomenon was verified by reverse transcription quantitative PCR (RT-qPCR) and flow cytometry. NK cells derived from Tigit-/- and wild-type (WT) mice were co-cultured with HSCs. It was found that Tigit-/- NK cells induced apoptosis in a higher proportion of HSCs than WT NK cells. Schistosomiasis infection models of Tigit-/- and WT mice were established. The proportion and killing activity of hepatic NK cells were significantly higher in Tigit-/- mice than in WT mice. The degree of liver fibrosis in Tigit-/- mice was significantly lower than that in WT mice. NK cells were isolated from Tigit-/- and WT mice and injected via the tail vein into WT mice infected with S. japonicum. The degree of liver fibrosis in mice that received NK cell infusion reduced significantly, but there was no significant difference between mice that received NK cells from Tigit-/- and WT mice, respectively. Our findings indicate that Tigit knockout enhanced the function of NK cells and reduced the degree of liver fibrosis in schistosomiasis, thus providing a novel strategy for treating hepatic fibrosis induced by schistosomiasis.

A Nomogram for Predicting Prognosis of Advanced Schistosomiasis japonica in Dongzhi County-A Case Study

BACKGROUNDS

Advanced schistosomiasis is the late stage of schistosomiasis, seriously jeopardizing the quality of life or lifetime of infected people. This study aimed to develop a nomogram for predicting mortality of patients with advanced schistosomiasis japonica, taking Dongzhi County of China as a case study.

METHOD

Data of patients with advanced schistosomiasis japonica were collected from Dongzhi Schistosomiasis Hospital from January 2019 to July 2022. Data of patients were randomly divided into a training set and validation set with a ratio of 7:3. Candidate variables, including survival outcomes, demographics, clinical features, laboratory examinations, and ultrasound examinations, were analyzed and selected by LASSO logistic regression for the nomogram. The performance of the nomogram was assessed by concordance index (C-index), sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). The calibration of the nomogram was evaluated by the calibration plots, while clinical benefit was evaluated by decision curve and clinical impact curve analysis.

RESULTS

A total of 628 patients were included in the final analysis. Atrophy of the right liver, creatinine, ascites level III, N-terminal procollagen III peptide, and high-density lipoprotein were selected as parameters for the nomogram model. The C-index, sensitivity, specificity, PPV, and NPV of the nomogram were 0.97 (95% [CI]: [0.95-0.99]), 0.78 (95% [CI]: [0.64-0.87]), 0.97 (95% [CI]: [0.94-0.98]), 0.78 (95% [CI]: [0.64-0.87]), 0.97 (95% [CI]: [0.94-0.98]) in the training set; and 0.98 (95% [CI]: [0.94-0.99]), 0.86 (95% [CI]: [0.64-0.96]), 0.97 (95% [CI]: [0.93-0.99]), 0.79 (95% [CI]: [0.57-0.92]), 0.98 (95% [CI]: [0.94-0.99]) in the validation set, respectively. The calibration curves showed that the model fitted well between the prediction and actual observation in both the training set and validation set. The decision and the clinical impact curves showed that the nomogram had good clinical use for discriminating patients with high risk of death.

CONCLUSIONS

A nomogram was developed to predict prognosis of advanced schistosomiasis. It could guide clinical staff or policy makers to formulate intervention strategies or efficiently allocate resources against advanced schistosomiasis.

Comparison of intestinal flora between patients with chronic and advanced Schistosoma japonicum infection

Background

Schistosoma japonicum infection is an important public health problem, imposing heavy social and economic burdens in 78 countries worldwide. However, the mechanism of transition from chronic to advanced S. japonicum infection remains largely unknown. Evidences suggested that gut microbiota plays a role in the pathogenesis of S. japonicum infection. However, the composition of the gut microbiota in patients with chronic and advanced S. japonicum infection is not well defined. In this study, we compared the composition of the intestinal flora in patients with chronic and advanced S. japonicum infection.

Methods

The feces of 24 patients with chronic S. japonicum infection and five patients with advanced S. japonicum infection from the same area were collected according to standard procedures, and 16S rRNA sequencing technology was used to analyze the intestinal microbial composition of the two groups of patients.

Results

We found that alteration occurs in the gut microbiota between the groups of patients with chronic and advanced S. japonicum infections. Analysis of alpha and beta diversity indicated that the diversity and abundance of intestinal flora in patients with advanced S. japonicum infection were lower than those in patients with chronic S. japonicum infection. Furthermore, Prevotella 9, Subdoligranulum, Ruminococcus torques, Megamonas and Fusicatenibacter seemed to have potential to discriminate different stages of S. japonicum infection and to act as biomarkers for diagnosis. Function prediction analysis revealed that microbiota function in the chronic group was focused on translation and cell growth and death, while that in the advanced group was concentrated on elevating metabolism-related functions.

Conclusions

Our study demonstrated that alteration in gut microbiota in different stages of S. japonicum infection plays a potential role in the pathogenesis of transition from chronic to advanced S. japonicum infection. However, further validation in the clinic is needed, and the underlying mechanism requires further study.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05539-6.