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Assessment of EN-RAGE, sRAGE and EN-RAGE/sRAGE as potential biomarkers in patients with autoimmune hepatitis

Abstract

Background

Autoimmune hepatitis (AIH) is a liver disease characterized by the autoimmune-induced injury of hepatocytes which can lead to cirrhosis and hepatic failure. The diagnosis and disease management of AIH patients remain challenging due to the diversity of clinical phenotypes and the presence of confounders such as alcohol and viruses. Recently, EN-RAGE and sRAGEs have been implicated in inflammatory-immune response. Nonetheless, their natural behaviour and relationship to disease activity as well as clinical predictive values in AIH development or therapy-induced remission have not been reported.

Methods

Sixty-seven AIH patients and thirty gender- and age-matched healthy controls (HC) were enrolled. The serum concentrations of EN-RAGE, sRAGE and their ratio (EN-RAGE/sRAGE) in these subjects were measured by ELISA. Besides, the correlations of three parameters with clinical features and therapeutic response were analyzed, respectively. Furthermore, their potential predictive values for monitoring the AIH progression and therapeutic response were also evaluated.

Results

Higher serum EN-RAGE, lower sRAGE and higher EN-RAGE/sRAGE value were observed in AIH patients. EN-RAGE and sRAGE as well as EN-RAGE/sRAGE were correlated with liver necroinflammation parameters, cirrhosis occurrence and therapeutic response. In addition, we identified that EN-RAGE/sRAGE, EN-RAGE and sRAGE had valuable predicting power for AIH patients, AIH patients with normal ALT and cirrhosis incidence, respectively. More importantly, EN-RAGE/sRAGE also exerted predicting power for the remission in AIH patients.

Conclusions

AIH patients rendered distinct patterns of serum EN-RAGE, sRAGE or EN-RAGE/sRAGE compared to healthy controls. Moreover, these three parameters exhibited potentials as novel biomarkers for AIH diagnosis and prognosis evaluation.

Background

Autoimmune hepatitis (AIH) is a liver-specific autoimmune disease characterized by hypergammaglobulinemia, increased circulating autoantibodies, transaminases, and histological evidence of interface hepatitis [1]. AIH occurs in all ethnicities and ages, with a female predominance. Intolerance to self-antigens followed by destruction of hepatic parenchyma by T lymphocyte-mediated response is identified as the key pathogenic mechanisms [2]. Untreated AIH can lead to liver cirrhosis and terminal failure [3]. So far, autoantibodies against nuclear antigens (ANA) or smooth muscle antibodies (ASMA), combination of liver kidney type 1 (LKM1) and other liver biochemical indexes such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma globulin and immunoglobulin G (IgG) are widely used as biomarkers for AIH diagnosis. However, the sensitivity and specificity of these markers for AIH diagnosis and evaluation of disease severity or therapeutic effect are still very limited, leading to misdiagnosis, inaccurate disease assessment and missing the treatable stage of AIH [4]. Therefore, unveiling new quantifiable biomarkers that are closely related to its pathogenesis as well as accurately reflects disease severity and therapeutic response is urgently needed.

The receptor for advanced glycation end products (RAGE), a receptor expressed on the cell surface, can be bound by multiple types of damage-associated molecular patterns (DAMPs), including S100/calgranulins, high-mobility group box 1 (HMGB1) and advanced glycation end products (AGEs), leading to the activation of the downstream cascades which is responsible for inflammatory-immune response [5]. Extracellular newly identified receptor for advanced glycation end products binding protein (EN-RAGE), also known as S100A12, is a calcium-binding proinflammatory protein predominantly secreted by activated granulocytes, macrophages and lymphocytes [6]. When secreted extracellularly, EN-RAGE, as one type of the DAMPs, induces persistent inflammatory-immune response by binding to RAGE followed by activation of intracellular signal cascades in lymphocytes and production of proinflammatory cytokines [7]. Increased serum EN-RAGE levels have been detected in multiple inflammatory-immune disorders [8, 9]. However, it is still unclear how EN-RAGE participates in the inflammatory-immune process and whether it can serve as a useful indicator for AIH progression.

Soluble RAGE (sRAGE), a splicing variant of the full-length receptor, is a soluble isoform containing only the RAGE extracellular domain formed by proteolytic cleavage. sRAGE counteracts DAMPs-RAGE interaction by sequestering and eliminating DAMPs [10]. Therefore, sRAGE can function as a “decoy” by binding to EN-RAGE and prevent the ligation between EN-RAGE and RAGE, which attenuate the inflammatory-immune response. Clinically, the serum levels of sRAGE are reduced in several types of auto-immune diseases, such as systemic lupus erythematosus [11], hashimoto's thyroiditis [12] and guillain-barré syndrome [13]. AIH is also an autoimmune disease with hepatocellular injury caused by liver-infiltrated T cells including T helper type 1 (Th1), Th2 and Th17 cells [1, 14]. T lymphocyte activation and differentiation was reported to be regulated by RAGE ligation by an in vivo mouse study [15]. Recent studies showed a protective role of sRAGE during the process of hepatocellular injury [16, 17]. However, the serum level of sRAGE in AIH and its underlying relationship with disease activity remain elusive.

The activation of RAGE by EN-RAGE and the antagonism by sRAGE results in inflammatory-immune responses augmentation and mitigation, respectively. Nonetheless, to date, the relationship of serum EN-RAGE or sRAGE levels with disease activity has not been well defined in AIH. In this study, we determined the serum levels of EN-RAGE and sRAGE as well as their ratio (EN-RAGE/sRAGE) and explored their correlation with clinical parameters in a well-defined cohort of AIH patients, aiming to explore whether EN-RAGE, sRAGE or EN-RAGE/sRAGE can be used as potential disease biomarkers during AIH progression.

Methods

Patients

Sixty-seven newly diagnosed AIH patients were prospectively recruited from the First and Second Affiliated Hospital of Chongqing Medical University from May 2016 to May 2018. Patients were not included if they were detected with other concomitant disease entities, including virus hepatitis, drug-induced hepatic injury, genetic and metabolic liver disease, hepatic malignancies, primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) and other autoimmune diseases. AIH was diagnosed according to the simplified criteria suggested by the IAIHG [18]. Clinical characteristics of patients were recorded at the time of AIH diagnosis. The patients were treated with decreasing doses of azathioprine and prednisone. Remission was defined according to the international guidelines. Biochemical remission was defined as the normalization of alanine aminotransferase (ALT), aspartate aminstransferase (AST) and IgG levels after treatment. Additionally, thirty age and gender-matched healthy controls [Age median and interquartile range (IQR): 48 (18); female, n (%): 49 (73.2%)] who did not have evidence of liver diseases or other chronic disorders were enrolled as healthy controls (HCs). All serum samples from thepatients and HCs were stored at − 80° until use. The study was approved by the Institutional Ethics Committee for human studies at Chongqing Medical University, Chongqing, China. All the procedures were following the Declaration of Helsinki. Patient characteristics were summarized in Table 1.

Table 1 The characteristics of enrolled individuals

Autoimmune serology and hepatic biochemical indexs and assessment

Antinuclear antibodies such as ANA and ASMA were measured by an automatic indirect immunofluorescence device Sprinter XL (EUROIMMUN, Cermany) and analyzed by automatic EUROP attern Microscope (EUROIMMUN, Cermany). Hepatic biochemical indexs such as alanine aminotransferase (ALT), aspartate aminstransferase (AST), albumin (ALB) and total bilirubin (TB) were measured by HITACHI 7600 (HITACHI, Japan). Immunoglobulin G (IgG) levels were detected by cobas c311 analyzer (Roche, Switzerland).

Enzyme-linked immunosorbent assay

Serum samples were analyzed by commercial human EN-RAGE (Cusabio, China) and sRAGE enzyme-linked immunosorbent assay kits (JYM, China) used according to the manufacturer’s instructions. Samples were run in duplicate.

Statistical analysis

Data were analyzed using SPSS 17.0. Mann–Whitney or Kruskal–Wallis test was performed to determine significance of EN-RAGE and sRAGE as well as their ratio (EN-RAGE/sRAGE) in AIH patients with various clinical and biochemical features. Correlation coefficients (r) were calculated using spearman correlation. Paired t test was used for EN-RAGE and sRAGE as well as EN-RAGE/sRAGE in AIH with remission analysis. Receiver operating characteristic (ROC) curves were generated to classify patients in different groups, as well as for the evaluation of predicting power for serum EN-RAGE and sRAGE as well as EN-RAGE/sRAGEvia calculation of the area under the ROC curve (AUC), sensitivity and specificity according to standard formulas. All the data represents the median and interquartile range (IQR); A p value < 0.05 was considered statistically significant.

Results

Serum levels of EN-RAGE, sRAGE and their ratio (EN-RAGE/sRAGE) in AIH patients

To assess whether serum levels of EN-RAGE and sRAGE are abnormally altered in AIH, we analyzed their levels in AIH and compare them to healthy controls (HC). The serum level of EN-RAGE was significantly higher in AIH patients [26.8 (14.31) ng/ml] than that of HC group [12.64 (10.06) ng/ml] (Fig. 1a). Contrarily, serum level of sRAGE was remarkably lower in AIH group [476.5 (395.8) pg/ml] than that of HC group [781.3 (482.2) pg/ml] (Fig. 1b). Additionally, serum level of EN-RAGE was negatively correlated with sRAGE (Fig. 1c). We then analyzed their ratio (EN-RAGE/sRAGE) in AIH, which showed that EN-RAGE/sRAGE was prominently higher in AIH group [61.54 (88.38)] compared to HC group [15.07 (18.78)] (Fig. 1d). AIH has a female predilection, we analyzed EN-RAGE, sRAGE and their ratio (EN-RAGE/sRAGE) in AIH patients with different genders. However, all the three parameters showed no significant differences between the male group [26.14 (9.84) ng/ml; 411.7 (380.4) pg/ml; 68.44 (98.36)] and female group [27.8 (21.76) ng/ml; 478.3 (402.8) pg/ml; 61.54 (84.71)] (Additional file 1: Fig.S1).

Fig. 1
figure1

Serum levels of EN-RAGE and sRAGE and their ratio (EN-RAGE/sRAGE) in AIH. a ELISA analysis of serum EN-RAGE levels from HC and AIH patients. b ELISA analysis of serum sRAGE levels from HC and AIH patients. c Correlation between serum EN-RAGE and sRAGE in AIH patients. d Analysis of EN-RAGE/sRAGE value in HC and AIH patients. Data represents the median (IQR). n number. ***p < 0.001

Circulating EN-RAGE and sRAGE as well as their ratio (EN-RAGE/sRAGE) in AIH patients with seropositive and seronegative pathogenic autoantibodies

AIH is defined by increased serum level of IgG and the presence of autoantibodies, nonetheless, none of the EN-RAGE, sRAGE nor EN-RAGE/sRAGE was correlated with IgG level (Fig. 2a-c). Since the circulating autoantibodies are the hallmarks of AIH diagnosis, the relationships between EN-RAGE, sRAGE or EN-RAGE/sRAGE and the presence of autoantibodies were determined. Whereas, the three parameters showed no statistic significant changes in autoantibodies-seropositive [34 (25.6) ng/ml; 544 (424.2) pg/ml; 69 (254.72)] AIH patients compared to seronegative [23.63 (11.04) ng/ml; 401.4 (342.6) pg/ml; 61.16 (90.71)] AIH patients (Fig. 2d-f). As ANA and ASMA are used as key serum diagnostic antibodies for AIH, we further determined the abundance of EN-RAGE, sRAGE or EN-RAGE/sRAGE in patients with different subtypes of autoantibodies. However, no significant differences were observed among ANA group, ASMA group and ANA + ASMA group (Fig. 2g-i).

Fig. 2
figure2

Relationship of EN-RAGE, sRAGE or EN-RAGE/sRAGE with pathogenic autoantibodies in AIH patients. ac Correlation between serum EN-RAGE (a), sRAGE (b) or EN-RAGE/sRAGE (c) and IgG levels in AIH patients. df Distribution of serum levels of EN-RAGE (d), sRAGE (e) and EN-RAGE/sRAGE value (f) in AIH patients with seropositive and seronegative pathogenic autoantibodies. gi Distribution of serum levels of EN-RAGE (g), sRAGE (h) and EN-RAGE/sRAGE (i) in AIH patients with ANA, ASMA or ANA + ASMA. Data represents the median (IQR). n number. Ns no statistical significance

Correlations of EN-RAGE, sRAGE and EN-RAGE/sRAGE with hepatic biochemical indexes

Hepatic biochemical necroinflammation indexes such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin (ALB), total bilirubin (TB) are crucial factors for reflecting liver functional state. We further analyzed the relationship between hepatic biochemical parameters and EN-RAGE, sRAGE or their ratio (EN-RAGE/sRAGE), respectively in AIH patients. Both serum EN-RAGE and the EN-RAGE/sRAGE ratio showed a positive correlation with ALT and AST but not ALB or TB in AIH patients (Table 2). In contrast, serum sRAGE was negatively correlated with ALT and AST but not with ALB and TB in AIH patients (Table 2).

Table 2 Correlations of EN-RAGE, sRAGE and their ratio (EN-RAGE/sRAGE) with hepatic biochemical indexs

Serum levels of EN-RAGE, sRAGE and EN-RAGE/sRAGE in AIH patients with cirrhosis

Autoimmune hepatitis without proper treatment can develop into liver cirrhosis. Therefore, we detected and analyzed the serum levels of EN-RAGE and sRAGE as well as their EN-RAGE/sRAGE value in AIH patients with and without liver cirrhosis. AIH patients with liver cirrhosis exhibited higher EN-RAGE levels [28.83 (26.73) ng/ml] than AIH patients without cirrhosis [23.46 (14.4) ng/ml] (Fig. 3a). Contrarily, AIH patients with liver cirrhosis showed lower sRAGE levels [221.7 (300.3) pg/ml] than the patients without cirrhosis [543 (336.3) pg/ml] (Fig. 3b). As a result, AIH patients with liver cirrhosis possessed higher EN-RAGE/sRAGE ratio [124.6 (296.15)] than the patients without cirrhosis [47.7 (48.01)] (Fig. 3c).

Fig. 3
figure3

Serum levels of EN-RAGE and sRAGE as well as EN-RAGE/sRAGE in AIH patients with and without cirrhosis. a Distribution of serum levels of EN-RAGE in AIH patients with and without cirhosis. b Distribution of serum levels of sRAGE in AIH patients with and without cirhosis. c Distribution EN-RAGE/sRAGE in AIH patients with and without cirhosis. n number. Data represents the median (IQR). ***p < 0.001

Recovery phase of AIH patients possess lower EN-RAGE and EN-RAGE/sRAGE but higher sRAGE

To further investigate the relationship of between therapeutic effect and EN-RAGE, sRAGE or EN-RAGE/sRAGE, twenty-one AIH patients who achieved disease remission were enrolled in this study. By monitoring serum EN-RAGE, sRAGE, EN-RAGE/sRAGE value and clinical parameters for these patients, we found that posttreatment group showed a striking reduction of ALT and AST but improved level of ALB, implying that there is a mitigation of liver damage and recovery of liver functions. Moreover, IgG level was decreased in the posttreatment group, suggesting that there is a disease remission upon the AIH therapy (Table 3). Interestingly, after the therapeutic treatment for AIH, serum levels of EN-RAGE were dramatically diminished while sRAGE were elevated (Fig. 4a, b). As expected, EN-RAGE/sRAGE value was also decreased in the remission phase of AIH patients (Fig. 4c). More importantly, EN-RAGE, sRAGE, EN-RAGE/sRAGE were significantly correlated with ALT and AST during the whole process of therapy, respectively (Fig. 4d-i).

Table 3 Effect of treatment on the values of clinical measures in AIH patients
Fig. 4
figure4

Serum levels of EN-RAGE and sRAGE as well as EN-RAGE/sRAGE before and after therapy of AIH patients. a Serum levels of EN-RAGE in AIH patients before and after therapy. b Serum levels of sRAGE in AIH patients before and after therapy. c EN-RAGE/sRAGE in AIH patients before and after therapy. df Correlation of serum EN-RAGE (d), sRAGE (e) or EN-RAGE/sRAGE value (f) with ALT in AIH patients before and after therapy. gi Correlation of serum EN-RAGE (g), sRAGE (h) or EN-RAGE/sRAGE (i) with AST in AIH patients before and after therapy. n number. ***p < 0.001

Diagnostic power of serum EN-RAGE, sRAGE and EN-RAGE/sRAGE for AIH progression

We next evaluated differentiating power of EN-RAGE, sRAGE and EN-RAGE/sRAGE for AIH. ROC analysis revealed that EN-RAGE, sRAGE, EN-RAGE/sRAGE yielded area under the ROC curve (AUC) of 0.88 (95% CI, 0.82–0.94), 0.80 (95% CI, 0.71–0.90) and 0.90 (95% CI, 0.85–0.96), respectively (Fig. 5a), in which EN-RAGE/sRAGE with highest AUC generated 70.14% sensitivity and 96.55% specificity with cutoff value 13.08, revealing that identified EN-RAGE/sRAGE has the highest diagnostic efficacy for AIH. Hepatic biochemical necroinflammation parameter ALT does not often correlate with the liver histological findings and disease severity in AIH patients, leading to misdiagnosis and inaccurate evaluation for therapeutic effect [19]. As mentioned above that there is a correlation between EN-RAGE, sRAGE or EN-RAGE/sRAGE and ALT, we next assessed whether they have predicting power for AIH patients with normal ALT. EN-RAGE, sRAGE or EN-RAGE/sRAGE yielded AUC of 0.85 (95% CI, 0.72–0.97), 0.75 (95% CI, 0.59–0.91) and 0.83 (95% CI, 0.70–0.98), respectively (Fig. 5b), in which serum EN-RAGE with highest AUC generated 68.75% sensitivity and 93.10% specificity with cutoff value 18.73 ng/ml, indicating that identified EN-RAGE has potential predicting power for AIH patients with normal ALT. To further evaluate whether EN-RAGE, sRAGE or EN-RAGE/sRAGE can predict AIH patients with cirrhosis, we analyzed the predictive power of the three indexs in AIH patients with cirrhosis versus patients without cirrhosis. EN-RAGE, sRAGE and EN-RAGE/sRAGE yielded AUC of 0.65 (95% CI, 0.51–0.78), 0.82 (95% CI, 0.72–0.92) and 0.78 (95% CI, 0.67–0.90) (Fig. 5c), in which serum sRAGE with highest AUC generated 89.74% sensitivity and 60.71% specificity with cutoff value 254.61 pg/ml, suggesting that sRAGE could efficiently discriminate AIH patients with cirrhosis. Furthermore, EN-RAGE, sRAGE and EN-RAGE/sRAGE yielded AUC of 0.82 (95% CI, 0.75–0.92), 0.69 (95% CI, 0.56–0.82) and 0.83 (95% CI, 0.73–0.93) for identifying AIH patients with therapeutic response versus treatment-naïve AIH patients (Fig. 5d), and EN-RAGE/sRAGE with highest AUC generated 76.1% sensitivity, 81% specificity with cutoff value 36.65, suggesting that identified EN-RAGE/sRAGE also has potential predicting power for the remission of AIH patients.

Fig. 5
figure5

Differentiating power of serum EN-RAGE and sRAGE as well as EN-RAGE/sRAGE for AIH with different parameter. a, b ROC curves of serum EN-RAGE and sRAGE as well as EN-RAGE/sRAGE for predicting AIH a and AIH with nomal ALT b from HC. c ROC curves of serum EN-RAGE and sRAGE as well as EN-RAGE/sRAGE for predicting AIH with cirhosis. d ROC curves of serum EN-RAGE and sRAGE as well as EN-RAGE/sRAGE for predicting AIH with remission

Discussion

AIH is an inflammatory liver disease characterized by liver immunotolerance failure leading to the destruction of hepatic parenchyma attacked by autoreactive T lymphocyte [14]. Elucidation of host inflammatory-immune response involved in AIH pathogenesis provides new perspectives for identification of biomarkers and therapeutic targets. EN-RAGE and sRAGE have recently gained interest because they function as important modulators in inflammatory immune response by acting on RAGE-mediated downstream cascades [5, 20]. Here, we assessed serum levels of EN-RAGE and sRAGE as well as their ratio EN-RAGE/sRAGE in AIH patients and analyzed their potential predicting power for disease progression and therapeutic response.

Growing evidence revealed that EN-RAGE/RAGE signaling pathway-mediated inflammatory-immune response play an important role in infection, autoimmunity and cancer [10, 21, 22]. However, the role of EN-RAGE/RAGE signaling in AIH-associated inflammatory-immune response has not been well-understood. Our present study demonstrated AIH patients exhibited elevated EN-RAGE and reduced sRAGE levels along with increased RAGE/sRAGE value in a well-defined cohort, indicating that EN-RAGE and sRAGE may exert opposite functions on regulating the AIH pathogenesis. This finding supports previous studies showing high EN-RAGE or low sRAGE levels in other inflammatory-immune disorders [23,24,25]. Based on data from assessment of differentiating power of EN-RAGE, sRAGE and EN-RAGE/sRAGE for AIH by ROC analysis, we identified EN-RAGE/sRAGE had the highest diagnostic efficacy.

The necroinflammation markers such as AST and ALT have been widely used for AIH diagnosis, prediction and monitoring disease activity [4]. Here, we observed significant correlations of EN-RAGE, sRAGE or EN-RAGE/sRAGE with these necroinflammatory indexs, implying that EN-RAGE/RAGE system activation may be involved in AIH-associated liver necroinflammatory. However, AIH patients may display normal ALT level leading to the inaccurate assessment of disease severity or even misdiagnosis [19]. In this study, we found that EN-RAGE has a predicting power for AIH patients with normal ALT. Mechanistically, AIH-associated liver injury is caused by autoimmune response to liver autoantigens, which involves a variety of immune cells, cytokines, autoantibodies and complement-mediated cytotoxicity. Various cytokines have been reported to participate in the pathogenesis of AIH. Th1 cytokine induce macrophage and T-cell activation, Th2 cytokine induce the production of autoantibodies and Th17 cytokines produce pro-inflammatory cytokines, all of which ultimately contribute to hepatocyte necroinflammation [1]. One previous in vivo study demonstrated that RAGE activation was responsible for the Th1 cell activation and cytokine production in pathogenesis of autoimmune response [15]. Secreted EN-RAGE was also reported to induce inflammatory-immune response-mediated proliferation and activation of mononuclear macrophage and lymphocyte by binding to RAGE [26]. Combining our present findings and previous studies, inflammatory-immune response triggered by EN-RAGE/RAGE ligation may participate in AIH-associated necroinflammatory activity.

Asymptomatic autoimmune hepatitis can lead to cirrhosis without treatment. Clinically, around 30% of AIH patients showed histological evidence of cirrhosis [27], suggesting early diagnosis of AIH accompanied by cirrhosis is pivotal. We found high EN-RAGE but low sRAGE levels alone with high EN/RAGE/sRAGE value in AIH with cirrhosis. Simultaneously, our present data identified that sRAGE could efficiently discriminate AIH patients with cirrhosis from without cirrhosis, generating 89.74% sensitivity and 60.71% specificity. Mechanistically, persistent AIH-mediated necroinflammation induces activation and differentiation of quiescent hepatic stellate cell and portal fibroblast into myofibroblast, a major contributor for collagen synthesis and extracellular matrix proteins (ECM) deposition, leading to the fibrous scar and terminal cirrhosis [28, 29]. Recently, elevated EN-RAGE and sRAGE were reported to involve diabetes-related cystic fibrosis and lead to worsening lung function [30]. EN-RAGE was also proven to activate fibroblast and cause dermal fibrosis by binding RAGE [31]. Therefore, we speculate that EN-RAGE/RAGE system activation might also involve in AIH-associated cirrhosis by acting on hepatic stellate cells or portal fibroblasts.

Prednisolone alone or in combination with azathioprine is the standard treatment for autoimmune hepatitis, and this treatment improves clinical, biochemical and histological features and prolongs survival in AIH patients [32]. In our present study, AIH posttreatment showed substantial normalization of clinical parameters ALT, AST and IgG. Previous study demonstrated that EN-RAGE was associated with response to therapy in juvenile idiopathic arthritis [33]. Here, we also observed an association of EN-RAGE, sRAGE or EN-RAGE/sRAGE with therapeutic effects. And a better predicting power from EN-RAGE/sRAGE was generated with AUC of 0.83, 76.1% sensitivity, 81% specificity for AIH patients with remission after prednisolone plus azathioprine treatment, suggesting that EN-RAGE/sRAGE may be potential candidate for the evaluation of therapeutic response in AIH patients.

Nonetheless, several limitations are existed in this study. Firstly, we did not assess the specificity of serum EN-RAGE and sRAGE for AIH compared to other liver autoimmune disease entities such as primary biliary cirrhosis, primary sclerosing cholangitis or their overlap syndrome. Secondly, our study was conducted in Chinese patients who were type I AIH. Further studies are required to confirm these results in type II AIH patients which mainly distributed in Europe and the United States. Finally, the detailed molecular mechanism regarding EN-RAGE/sRAGE signaling activation in AIH pathogenesis and whether sRAGE can serve as a therapeutic target still need further clarification.

Conclusions

In conclusion, this study demonstrated that AIH patients rendered distinct patterns of serum EN-RAGE, sRAGE or EN-RAGE/sRAGE compared to healthy controls. In addition, three parameters were correlated with necroinflammation, cirrhosis incidence and therapeutic response. Furthermore, we identified EN-RAGE/sRAGE, EN-RAGE and sRAGE, had predicting power for AIH patients, AIH patients with normal ALT and cirrhosis incidence, respectively. More importantly, EN-RAGE/sRAGE also exerted predicting power for therapeutic response in AIH patients. Taken together, our findings indicate that serum EN-RAGE, sRAGE or EN-RAGE/sRAGE exhibited potentials as novel biomarkers for the diagnosis and prognosis evaluation in AIH patients, opening a very attractive field of research on these molecules in the pathology of AIH and identification of therapeutic targets.

Availability of data and materials

Not applicable.

Abbreviations

AIH:

Autoimmune hepatitis

HC:

Healthy control

ANA:

Against nuclear antigens

ASMA:

Smooth muscle antibodies

LKM1:

Combination of liver kidney type 1

ALT:

Alanine aminotransferase

AST:

Aspartate aminotransferase

IgG:

Immunoglobulin G

RAGE:

Receptor for advanced glycation end products

DAMP:

Damage-associated molecular patterns

AGEs:

Advanced glycation end products

EN-RAGE:

Extracellular newly identified receptor for advanced glycation end products binding protein

sRAGE:

Soluble RAGE

Th1:

T helper type 1

PBC:

Primary biliary cholangitis

PSC:

Primary sclerosing cholangitis

ALT:

Alanine aminotransferase

AST:

Aspartate aminstransferase

ALB:

Albumin

TB:

Total bilirubin

References

  1. 1.

    Assis DN. Immunopathogenesis of autoimmune hepatitis. Clin Liver Dis (Hoboken). 2020;15:129–32.

    Article  Google Scholar 

  2. 2.

    Tanaka A. Autoimmune Hepatitis: 2019 Update. Gut Liver. 2020;14(4):430–8.

    Article  Google Scholar 

  3. 3.

    Tiniakos DG, Brain JG, Bury YA. Role of histopathology in autoimmune hepatitis. Dig Dis. 2015;33(Suppl 2):53–64.

    Article  Google Scholar 

  4. 4.

    Czaja AJ. Emerging therapeutic biomarkers of autoimmune hepatitis and their impact on current and future management. Expert Rev Gastroenterol Hepatol. 2018;12:547–64.

    CAS  Article  Google Scholar 

  5. 5.

    Hudson BI, Lippman ME. Targeting RAGE signaling in inflammatory disease. Annu Rev Med. 2018;69:349–64.

    CAS  Article  Google Scholar 

  6. 6.

    Meijer B, Gearry RB, Day AS. The Role of S100A12 as a SystemicMarker of Inflammation. Int J Inflamm. 2012;2012:1–6.

    Article  Google Scholar 

  7. 7.

    Foell D, Wittkowski H, Vogl T, Roth J. S100 proteins expressed in phagocytes: a novel group of damage-associated molecular pattern molecules. J Leukoc Biol. 2007;81:28–37.

    CAS  Article  Google Scholar 

  8. 8.

    van de Logt F, Day AS. S100A12: a noninvasive marker of inflammation in inflammatory bowel disease. J Dig Dis. 2013;14:62–7.

    Article  Google Scholar 

  9. 9.

    Carvalho A, Lu J, Francis JD, Moore RE, Haley KP, Doster RS, Townsend SD, Johnson JG, Damo SM, Gaddy JA. S100A12 in digestive diseases and health: a scoping review. Gastroenterol Res Pract. 2020;2020:2868373.

    Article  Google Scholar 

  10. 10.

    Ahmad S, Khan H, Siddiqui Z, Khan MY, Rehman S, Shahab U, Godovikova T, Silnikov V. Moinuddin: AGEs, RAGEs and s-RAGE; friend or foe for cancer. Semin Cancer Biol. 2018;49:44–55.

    CAS  Article  Google Scholar 

  11. 11.

    Ma CY, Ma JL, Jiao YL, Li JF, Wang LC, Yang QR, You L, Cui B, Chen ZJ, Zhao YR. The plasma level of soluble receptor for advanced glycation end products is decreased in patients with systemic lupus erythematosus. Scand J Immunol. 2012;75:614–22.

    CAS  Article  Google Scholar 

  12. 12.

    Aversa T, Ruggeri RM, Corica D, Cristani MT, Mirabelli S, Vicchio TM, Trimarchi F, De Luca F, Wasniewska M. Serum levels of the soluble receptor for advanced glycation end products are reduced in children with hashimoto's thyroiditis. Horm Res Paediatr. 2018;90:89–90.

    Google Scholar 

  13. 13.

    Zhang DQ, Wang R, Li T, Zhou JP, Chang GQ, Zhao N, Yang LN, Zhai H, Yang L. Reduced soluble RAGE is associated with disease severity of axonal Guillain-Barre syndrome. Sci Rep. 2016. https://doi.org/10.1038/srep21890.

    Article  PubMed  PubMed Central  Google Scholar 

  14. 14.

    Doycheva I, Watt KD, Gulamhusein AF. Autoimmune hepatitis: current and future therapeutic options. Liver Int. 2019;39:1002–133.

    Article  Google Scholar 

  15. 15.

    Chen Y, Akirav EM, Chen W, Henegariu O, Moser B, Desai D, Shen JM, Webster JC, Andrews RC, Mjalli AM, et al. RAGE ligation affects T cell activation and controls T cell differentiation. J Immunol. 2008;181:4272–8.

    CAS  Article  Google Scholar 

  16. 16.

    Ivancovsky-Wajcman D, Zelber-Sagi S, Fliss Isakov N, Webb M, Zemel M, Shibolet O, Kariv R. Serum soluble receptor for age (sRAGE) levels are associated with unhealthy lifestyle and nonalcoholic fatty liver disease. Clin Transl Gastroenterol. 2019;10:1–10.

    Article  Google Scholar 

  17. 17.

    Palma-Duran SA, Kontogianni MD, Vlassopoulos A, Zhao S, Margariti A, Georgoulis M, Papatheodoridis G, Combet E. Serum levels of advanced glycation end-products (AGEs) and the decoy soluble receptor for AGEs (sRAGE) can identify non-alcoholic fatty liver disease in age-, sex- and BMI-matched normo-glycemic adults. Metabolism. 2018;83:120–7.

    CAS  Article  Google Scholar 

  18. 18.

    Hennes EM, Zeniya M, Czaja AJ, Pares A, Dalekos GN, Krawitt EL, Bittencourt PL, Porta G, Boberg KM, Hofer H, et al. Simplified criteria for the diagnosis of autoimmune hepatitis. Hepatology. 2008;48:169–76.

    Article  Google Scholar 

  19. 19.

    Alvarez F, Berg PA, Bianchi FB, Bianchi L, Burroughs AK, Cancado EL, Chapman RW, Cooksley WG, Czaja AJ, Desmet VJ, et al. International Autoimmune Hepatitis Group Report: review of criteria for diagnosis of autoimmune hepatitis. J Hepatol. 1999;31:929–38.

    CAS  Article  Google Scholar 

  20. 20.

    Bongarzone S, Savickas V, Luzi F, Gee AD. Targeting the receptor for advanced glycation endproducts (RAGE): a medicinal chemistry perspective. J Med Chem. 2017;60:7213–32.

    CAS  Article  Google Scholar 

  21. 21.

    van Zoelen MA, Achouiti A, van der Poll T. RAGE during infectious diseases. Front Biosci (Schol Ed). 2011;3:1119–32.

    Article  Google Scholar 

  22. 22.

    Yamagishi S, Matsui T. Soluble form of a receptor for advanced glycation end products (sRAGE) as a biomarker. Front Biosci (Elite Ed). 2010;2:1184–95.

    Article  Google Scholar 

  23. 23.

    Borsky P, Fiala Z, Andrys C, Beranek M, Hamakova K, Malkova A, Svadlakova T, Krejsek J, Palicka V, Borska L, Rehacek V. Alarmins HMGB1, IL-33, S100A7, and S100A12 in Psoriasis Vulgaris. Mediators Inflamm. 2020;2020:8465083.

    Article  Google Scholar 

  24. 24.

    Angelopoulou E, Paudel YN, Piperi C. Unraveling the role of receptor for advanced glycation end products (RAGE) and its ligands in myasthenia gravis. ACS Chem Neurosci. 2020;11:663–73.

    CAS  Article  Google Scholar 

  25. 25.

    Ruggeri RM, Barbalace MC, Cristani MT, Alibrandi A, Giovinazzo S, Giuffrida G, Trimarchi F, Cannavo S, Campenni A. Serum levels of advanced glycation end products (AGEs) are increased and their soluble receptor (sRAGE) reduced in Hashimoto's thyroiditis. J Endocrinol Invest. 2020;43(9):1337–422.

    CAS  Article  Google Scholar 

  26. 26.

    Schmidt AM, Yan SD, Yan SF, Stern DM. The multiligand receptor RAGE as a progression factor amplifying immune and inflammatory responses. J Clin Invest. 2001;108:949–55.

    CAS  Article  Google Scholar 

  27. 27.

    Feld JJ, Dinh H, Arenovich T, Marcus VA, Wanless IR, Heathcote EJ. Autoimmune hepatitis: effect of symptoms and cirrhosis on natural history and outcome. Hepatology. 2005;42:53–62.

    Article  Google Scholar 

  28. 28.

    Wick G, Grundtman C, Mayerl C, Wimpissinger TF, Feichtinger J, Zelger B, Sgonc R, Wolfram D. The immunology of fibrosis. Annu Rev Immunol. 2013;31:107–35.

    CAS  Article  Google Scholar 

  29. 29.

    Montano-Loza AJ, Thandassery RB, Czaja AJ. Targeting hepatic fibrosis in autoimmune hepatitis. Dig Dis Sci. 2016;61:3118–399.

    CAS  Article  Google Scholar 

  30. 30.

    Mulrennan S, Baltic S, Aggarwal S, Wood J, Miranda A, Frost F, Kaye J, Thompson PJ. The role of receptor for advanced glycation end products in airway inflammation in CF and CF related diabetes. Sci Rep. 2015;5:8931.

    Article  Google Scholar 

  31. 31.

    Zhao J, Zhong A, Friedrich EE, Jia S, Xie P, Galiano RD, Mustoe TA, Hong SJ. S100A12 induced in the epidermis by reduced hydration activates dermal fibroblasts and causes dermal fibrosis. J Invest Dermatol. 2017;137:650–9.

    CAS  Article  Google Scholar 

  32. 32.

    Pape S, Schramm C, Gevers TJ. Clinical management of autoimmune hepatitis. United Eur Gastroenterol J. 2019;7:1156–63.

    CAS  Article  Google Scholar 

  33. 33.

    Gohar F, Anink J, Moncrieffe H, Van Suijlekom-Smit LWA, Prince FHM, van Rossum MAJ, Dolman KM, Hoppenreijs E, Ten Cate R, Ursu S, et al. S100A12 is associated with response to therapy in juvenile idiopathic arthritis. J Rheumatol. 2018;45:547–54.

    CAS  Article  Google Scholar 

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Acknowledgements

Not applicable.

Funding

This work was supported by Natural Science Foundation of Chongqing (cstc2019jcyj-msxmX0859 to RW), National Natural Science Foundation of China (81601837 to LD) and the Chongqing Health Commission (2019QNXM028 to LD).

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Authors

Contributions

LD, XL and RY contributed to the conception and design of the study. RW, RY and LD coordinated the investigation of subjects’ sample analysis. RW and YL Performed the experiments. XL and LD performed data analysis and interpretation. XL and LD drafted the manuscript. All authors read and approved the final manuscript.

Corresponding authors

Correspondence to Rui Wu or Xiaoyu Liu or Liang Duan.

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Patients were consented for serum acquisition per institutional review board (IRB)-approved protocol.

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The authors declare that there is no competing interests regarding the publication of this paper.

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Supplementary information

Additional file 1:

Figure S1. Serum levels of EN-RAGE and sRAGE as well as EN-RAGE/sRAGE in AIH patients with different genders.

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Wu, R., Liu, Y., Yan, R. et al. Assessment of EN-RAGE, sRAGE and EN-RAGE/sRAGE as potential biomarkers in patients with autoimmune hepatitis. J Transl Med 18, 384 (2020). https://doi.org/10.1186/s12967-020-02556-w

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Keywords

  • EN-RAGE
  • sRAGE
  • Autoimmune hepatitis
  • Inflammatory-immune response