Leucine-rich Α2-glycoprotein Research Articles

Leucine rich α2 glycoprotein 1 derived from malignant pleural mesothelioma cells facilitates macrophage M2 phenotypes

Background: Macrophages constitute the main part of infiltrating immune cells in Malignant pleural mesothelioma (MPM) and abnormally high ratios of M2 macrophages are present in both pleural effusion and tissue samples of MPM patients. Whether MPM cells affect formation of M2 macrophages is poorly understood. In this study, we focused on identification of MPM-cells-derived soluble factors with M2-promoting effects. Methods: Media of malignant pleural mesothelioma cells were collected and soluble factors affecting macrophages were analyzed by mass spectrometry. TGF-β receptor inhibitor SB431542 was used as the entry point to explore the downstream mechanism of action by qRT-PCR, WB and immunofluorescence. Results: The serum-free culture media collected from the human MPM cells Meso1 and Meso2 significantly enhanced expression of the M2 signature molecules including IL-10, TGF-β and CD206 in the human macrophages THP-1, while the culture medium of the human MPM cells H2452 did not show such M2-promoting effects. Analysis of proteins by mass spectrometry and ELISA suggested that Leucine rich α2 glycoprotein 1(LRG1) was a potential candidate. LRG1 time- and dose-dependently increased expression of the M2 signature molecules, confirming its M2-promoting effects. Furthermore, LRG1’s M2-promoting effects were reduced by the TGF-β receptor inhibitor SB431542, and LRG1 increased phosphorylation of Smad2, indicating that M2-promoting effects of LRG1 were via the TGF-β receptor/Smad2 signaling pathway. Conclusions: Our results provide a potential M2-promoting new member, LRG1, which contributes to the immune escape of MPM via the TGF-β receptor/Smad2 signaling pathway.

Early change in serum leucine-rich α-2-glycoprotein predicts clinical and endoscopic response in ulcerative colitis.

Leucine-rich α-2-glycoprotein (LRG) is a new serum biomarker reflecting the disease activity of ulcerative colitis (UC), but its change during the acute phase has not been enough investigated. Patients with UC who initiated the induction therapy with steroid or advanced therapy (biologics or Janus kinase inhibitors) were prospectively enrolled. Associations of LRG, C-reactive protein (CRP) and fecal calprotectin (FC) at baseline, week 1, and week 8 with clinical remission at week 8 and subsequent endoscopic improvement within 1 year (Mayo endoscopic subscore of 0 or 1) were assessed. A total of 143 patients with UC were included. LRG and CRP at week 1 were significantly lower in the clinical remission group than in the non-remission group (LRG, 20.6 μg/mL vs. 28.4 μg/mL, P< 0.001; CRP, 0.9 mg/dL vs. 2.3 mg/dL, P< 0.001) while FC demonstrated the difference between groups only at week 8. The area under the curves of week 1 LRG, CRP, and FC for week 8 clinical remission using the receiver operating characteristic curves analysis were 0.68, 0.71, and 0.57, respectively. Furthermore, LRG and CRP predicted subsequent endoscopic improvement as early as week 1, while FC was predictive only at week 8. LRG can be an early-phase biomarker predicting subsequent clinical and endoscopic response to induction therapy.

LRG1 loss effectively restrains glomerular TGF-β signaling to attenuate diabetic kidney disease

Transforming growth factor (TGF)-β signaling is a well-established pathogenic mediator of diabetic kidney disease (DKD). However, owing to its pleiotropic actions, its systemic blockade is not therapeutically optimal. The expression of TGF-β signaling regulators can substantially influence TGF-β's effects in a cell- or context-specific manner. Among these, leucine-rich α2-glycoprotein 1 (LRG1) is significantly increased in glomerular endothelial cells (GECs) in DKD. As LRG1 is a secreted molecule that can exert autocrine and paracrine effects, we examined the effects of LRG1 loss in kidney cells in diabetic OVE26 mice by single-cell transcriptomic analysis. Gene expression analysis confirmed a predominant expression of Lrg1 in GECs, which further increased in diabetic kidneys. Loss of Lrg1 led to the reversal of angiogenic and TGF-β-induced gene expression in GECs, which were associated with DKD attenuation. Notably, Lrg1 loss also mitigated the increased TGF-β-mediated gene expression in both podocytes and mesangial cells in diabetic mice, indicating that GEC-derived LRG1 potentiates TGF-β signaling in glomerular cells in an autocrine and paracrine manner. Indeed, a significant reduction in phospho-Smad proteins was observed in the glomerular cells of OVE26 mice with LRG1 loss. These results indicate that specific antagonisms of LRG1 may be an effective approach to curb the hyperactive glomerular TGF-β signaling to attenuate DKD.

A low baseline serum myostatin concentration is associated with poor clinical outcome in patients with primary biliary cholangitis.

Primary biliary cholangitis (PBC) is an autoimmune-mediated cholestatic liver disease that can progress to biliary cirrhosis and liver-related death. The associations between baseline myostatin levels and clinical outcomes in PBC patients are unknown. We aimed to clarify the influence of myostatin levels on the clinical outcomes of PBC patients. A total of 119 PBC patients were analyzed in this study. Myostatin levels were measured in stored sera before ursodeoxycholic acid treatment, and their associations with the clinical features and prognosis of PBC patients were analyzed. We analyzed the correlation between serum myostatin and chemokines/cytokines. Serum myostatin was significantly lower in PBC patients (2343pg/mL) than in healthy controls (4059pg/mL, P<0.001). The prevalence of patients with low myostatin levels increased according to the severity of histological fibrosis. The serum myostatin concentration was negatively correlated with the IL-6 and leucine-rich α2 glycoprotein levels, but the chemokine concentration was not correlated with the myostatin concentration. Low myostatin in PBC patients was associated with shorter survival without liver-related complications (hazard ratio [HR], 3.598; 95% confidence interval [CI], 1.27-10.1; P=0.015) and shorter transplant-free survival (HR, 3.129; 95% CI, 1.02-9.56; P=0.045) independent of pretreatment GLOBE score. Patients with both high pretreatment GLOBE scores and low myostatin levels had poor prognoses (log-rank test: P<0.001). A low serum myostatin concentration at diagnosis was associated with poor clinical outcomes. Assessment of circulating myostatin levels may improve the prediction of outcomes in patients with PBC.

Serum Leucine-Rich α2 Glycoprotein Could Be a Useful Biomarker to Differentiate Patients with Normal Colonic Mucosa from Those with Inflammatory Bowel Disease or Other Forms of Colitis.

(1) Background: Serum leucine-rich α2 glycoprotein (LRG) has been reported as a useful biomarker for monitoring disease activity in patients with inflammatory bowel disease (IBD). We investigated whether serum LRG can differentiate patients with normal colonic mucosa from those with IBD or other forms of colitis. (2) Methods: Patients with diarrhea, abdominal pain, or bloody stools were consecutively enrolled at their initial visit to our hospital. Serum LRG and C-reactive protein were measured, and a colonoscopy and histology were performed. (3) Results: We enrolled 317 patients (181 men, 136 women; median age: 51 years). Based on the endoscopic and histological criteria, 260 patients were diagnosed with ulcerative colitis (n = 134), Crohn's disease (n = 10), infectious colitis (n = 43), diverticular colitis (n = 17), or nonspecific colitis (n = 56). The remaining 57 patients were diagnosed with normal colonic mucosa including histology. The latter group's median LRG value (9.5 µg/mL, range: 5.8-13.5) was significantly lower than that of the other 260 patients (13.6 µg/mL, range: 6.8-62.7, p < 0.0001). The optimal LRG cut-off value of <10.4 µg/mL was derived from the receiver operating characteristic (ROC) curve, showing a 91% sensitivity and 77% specificity for identifying patients with normal colonic mucosa. (4) Conclusions: serum LRG values < 10.4 µg/mL could be a useful biomarker for predicting patients with normal colonic mucosa.

Retracted: The Prognostic Value of Leucine-Rich α2 Glycoprotein 1 in Pediatric Spinal Cord Injury.

[This retracts the article DOI: 10.1155/2021/7365204.].

One-Step Affinity Purification of Leucine-Rich α2-Glycoproteins from Snake Sera and Characterization of Their Phospholipase A2-Inhibitory Activities as β-Type Phospholipase A2 Inhibitors.

Snakes contain three types of phospholipase A2 (PLA2)-inhibitory proteins in their blood, PLIα, β, and γ, which protect them from their own venom, PLA2. PLIβ is the snake ortholog of leucine-rich α2 glycoprotein (LRG). Since autologous cytochrome c (Cyt c) serves as an endogenous ligand for LRG, in this study, we purified snake LRGs from various snake serum samples using Cyt c affinity chromatography. All purified snake LRGs were found to be dimers linked by disulfide bonds. Laticauda semifasciata and Naja kaouthia LRGs showed no inhibitory activity against L. semifasciata PLA2 and weak inhibitory activity against Gloydius brevicauda basic PLA2. Elaphe climacophora PLIβ had weaker inhibitory activity against G. brevicauda basic PLA2 than G. brevicauda and Elaphe quadrivirgata PLIs, which are abundant in blood and known to neutralize G. brevicauda basic PLA2. Protobothrops flavoviridis LRG showed no inhibitory activity against basic venom PLA2, PL-X, or G. brevicauda basic PLA2. Binding analysis of P. flavoviridis LRG using surface plasmon resonance showed very strong binding to snake Cyt c, followed by that to horse Cyt c, weak binding to yeast Cyt c, and no binding to P. flavoviridis PL-X or BPI/II. We also deduced the amino acid sequences of L. semifasciata and P. flavoviridis LRG by means of cDNA sequencing and compared them with those of other known sequences of PLIs and LRGs. This study concluded that snake LRG can potentially inhibit basic PLA2, but, whether it actually functions as a PLA2-inhibitory protein, PLIβ, depends on the snake.

Leucine-rich α2-glycoprotein as a useful biomarker for evaluating disease activity in rheumatoid arthritis.

Leucine-rich α2-glycoprotein as a useful biomarker for evaluating disease activity in rheumatoid arthritis.

Serum leucine-rich α2-glycoprotein is a useful biomarker for generalized pustular psoriasis.

Serum leucine-rich α2-glycoprotein is a useful biomarker for generalized pustular psoriasis.

The Leucine-Rich α2-Glycoprotein-1 Levels in Patients with Multiple Myeloma

Introduction: Angiogenesis is considered important in the pathogenesis of multiple myeloma (MM), as well as in the targeted treatment of the disease. Leucine-rich α2-glycoprotein 1 (LRG1) is a protein that participates in angiogenesis and its effect on solid organ tumors has been investigated recently. This study aimed to investigate the relationship between MM and LRG1. Methods: The MM patients who admitted to Hatay Mustafa Kemal University Hematology Clinic between September 2021 and October 2022 were included in the study. The study consists of a total of 4 groups: newly diagnosed MM (NDMM), relapsed refractory MM (RRMM), MM in remission (Rem-MM), and control group. Demographic data were retrieved from hospital records. Blood samples of our study groups were centrifuged at 1,500 × g for 10 min and serum was collected. LRG1, IL-6, IL-8, TGF-β1, HIF-1α, FGF-2, and VEGF levels were analyzed in all groups by ELISA method, and statistical analysis was performed. Results: A total of 112 individuals, including NDMM (n: 27), RRMM (n: 18), Rem-MM (n: 42), and control group (n: 25), were enrolled in the study. Based on the analyses, the NDMM group exhibited significantly elevated levels of LRG1 (p < 0.001), TGF-1 (p < 0.001), and HIF-1α (p = 0.046, p < 0.001, and p = 0.003 compared to the RRMM, Rem-MM, and control groups, respectively) compared to the other groups. LRG1 levels were positively correlated with creatinine (r: 0.363, p = 0.001), calcium (r: 0.344, p = 0.001), total protein (r: 0.473, p < 0.001), erythrocyte sedimentation rate (r: 0.547, p < 0.001), lactate dehydrogenase (r: 0.321, p = 0.003), beta-2-microglobulin (r: 0.312, p = 0.017), IL-6 (r: 0.478, p < 0.001), IL-8 (r: 0.240, p = 0.03), TGF-β1 (r: 0.521, p < 0.001), and HIF-1α (r: 0.321, p = 0.003) levels and were negatively correlated with hemoglobin (r: −0.512, p < 0.001) and albumin (r: −0.549, p < 0.001) levels. Receiver operating characteristics (ROC) analysis revealed the association of LRG1 with the highest AUC value of 0.959 (95% CI: 0.904–1, p < 0.001) and the optimal cut-off value of 534.95 ng/mL (sensitivity: 93% and specificity: 99%) in the NDMM group compared to the control group. Conclusion: In this study, providing data for the first time on LRG1 levels in the setting of MM. LRG1 levels were found to be significantly higher in NDMM patients and in our study discriminate this patient population from RRMM, Rem-MM, and normal controls. Therefore, LRG1 seems to a potential biomarker that should be evaluated in future studies addressing the diagnosis, staging, follow-up, prognosis, and treatment target of MM.

Leucine-rich alpha-2 glycoprotein as a potential biomarker for large vessel vasculitides.

Serum levels of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) have been used as useful biomarkers for reflecting the activity of large vessel vasculitides (LVV). However, a novel biomarker that could have a complementary role to these markers is still required. In this retrospective observational study, we investigated whether leucine-rich α-2 glycoprotein (LRG), a known biomarker in several inflammatory diseases, could be a novel biomarker for LVVs. 49 eligible patients with Takayasu arteritis (TAK) or giant cell arteritis (GCA) whose serum was preserved in our laboratory were enrolled. The concentrations of LRG were measured with an enzyme-linked immunosorbent assay. The clinical course was reviewed retrospectively from their medical records. The disease activity was determined according to the current consensus definition. The serum LRG levels were higher in patients with active disease than those in remission, and decreased after the treatments. While LRG levels were positively correlated with both CRP and erythrocyte sedimentation rate, LRG exhibited inferior performance as an indicator of disease activity compared to CRP and ESR. Of 35 CRP-negative patients, 11 had positive LRG. Among the 11 patients, two had active disease. This preliminary study indicated that LRG could be a novel biomarker for LVV. Further large studies should be required to promise the significance of LRG in LVV.

Leucine-Rich Alpha-2-Glycoprotein: A Novel Predictor of Diastolic Dysfunction

Leucine-rich α2-glycoprotein (LRG1) mediates cardiac fibrocyte activation. It is upregulated in inflammatory conditions, atherosclerosis, and fibrosis. Diastolic dysfunction (DD) is due to myocardial fibrosis. This cross-sectional study examined the relationship between LRG1 and DD. Patients with symptoms of chronic coronary ischemia were recruited. Patients with symptoms of overt heart failure, ejection fraction (EF) < 55%, impaired renal function, infection, and recent trauma were excluded from the study. Clinical parameters examined were SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery (SYNTAX) score, echocardiographic assessment, and LRG1 levels. Binary stepwise logistic regression was used to evaluate the association between LRG1 and DD. Receiver Operating Characteristic (ROC) analysis was used to determine optimal cut-off values and predictive performance of LRG1. A total of 94 patients were enrolled in the study, with 47 having a clinical diagnosis of DD. Plasma LRG1 was significantly (U = 417.00, p < 0.001) higher in the DD group (M = 14) compared to the No-DD group (M = 8) by Mann-Whitney U test. There were higher SYNTAX scores in the DD group (M = 24.5) compared with No-DD (M = 7). LRG1 had significant predictability of DD (OR = 1.32 (95% CI: 1.14-1.53)). The ROC showed an AUC = 0.89 (95% CI: 0.82-0.95). LRG1 had a 78% sensitivity (95% CI: 65.3-87.7) and 72.3% specificity (95% CI: 57.4-84.4) for predicting DD at a cut-off value of "9". In conclusion, we identified LRG1 as a novel independent predictor of DD. Further studies are warranted to validate the utility of LRG1 in predicting DD.

Serum leucine-rich α2 glycoprotein as a potential biomarker for systemic inflammation in Parkinson's disease.

There is ample epidemiological and animal-model evidence suggesting that intestinal inflammation is associated with the development of Parkinson's disease (PD). Leucine-rich α2 glycoprotein (LRG) is a serum inflammatory biomarker used to monitor the activity of autoimmune diseases, including inflammatory bowel diseases. In this study, we aimed to investigate whether serum LRG could be used a biomarker of systemic inflammation in PD and to help distinguish disease states. Serum LRG and C-reactive protein (CRP) levels were measured in 66 patients with PD and 31 age-matched controls. We found that serum LRG levels were statistically significantly higher in the PD group than in the control group (PD: 13.9 ± 4.2 ng/mL, control: 12.1 ± 2.7 ng/mL, p = 0.036). LRG levels were also correlated with Charlson comorbidity index (CCI) and CRP levels. LRG levels in the PD group were correlated with Hoehn and Yahr stages (Spearman's r = 0.40, p = 0.008). LRG levels were statistically significantly elevated in PD patients with dementia as compared to those without dementia (p = 0.0078). Multivariate analysis revealed a statistically significant correlation between PD and serum LRG levels after adjusting for serum CRP levels, and CCI (p = 0.019). We conclude that serum LRG levels could be considered a potential biomarker for systemic inflammation in PD.

Evaluation of Crohn's Disease Small-Bowel Mucosal Healing Using Capsule Endoscopy and Usefulness of Leucine-Rich α2-Glycoprotein.

Recently, the importance of achieving clinical and deep remissions with mucosal healing (MH) has been demonstrated as a therapeutic goal to avoid Crohn's disease (CD) surgical operations. Although ileocolonoscopy (CS) is considered the gold standard, there are increasing reports on the benefits of capsule endoscopy (CE) and serum leucine-rich α2-glycoprotein (LRG) for evaluating small-bowel lesions in CD. We evaluated the data of 20 patients with CD who underwent CE in our department between July 2020 and June 2021 and whose serum LRG level was measured within 2 months. Concerning the mean LRG value, there was no significant difference between the CS-MH and CS-non-MH groups. Conversely, the mean LRG level was 10.0 μg/mL in seven patients in the CE-MH group and 15.2 μg/mL in 11 patients in the CE-non-MH group with a significant difference between the two groups (p = 0.0025). This study's findings show that CE can sufficiently determine total MH in most cases, and LRG is useful for evaluating CD small-bowel MH because of its correlation with CE-MH. Furthermore, satisfying CS-MH criteria and a cut-off value of 13.4 μg/mL for LRG suggests its usefulness as a CD small-bowel MH marker, which could be incorporated into the treat-to-target strategy.

Serum leucine-rich α2-glycoprotein as a possible marker for inflammatory status in endometriosis.

This study aimed to investigate whether serum leucine-rich α2-glycoprotein (LRG) is a useful diagnostic biomarker for endometriosis, including the evaluation of treatment efficacy and exploration of LRG production in endometriotic lesions. Forty-three women with endometriomas were compared to 22 women with benign ovarian cysts and 30 women who underwent assisted reproduction as controls. Changes in serum LRG levels were assessed before and after surgery, and during dienogest treatment. LRG expression in endometriotic tissue samples was evaluated using immunoblotting. Serum LRG levels in the endometrioma group (80.0 ± 36.3 μg/mL) were significantly higher than those in the benign ovarian cyst (65.1 ± 27.0 μg/mL, p = 0.0265) and control (57.8 ± 22.3 μg/mL, p = 0.0028) groups. Serum LRG levels after endometrioma surgery were significantly lower than preoperative levels (p = 0.0484). Serum LRG levels consistently decreased during dienogest treatment. LRG expression levels were significantly higher in endometriotic tissues than in the normal endometrium. Serum LRG, possibly derived from local and systemic origins, could be used as a potential biomarker for the diagnosis and treatment of endometriosis.

Serum Leucine-Rich α2 Glycoprotein: A Novel Biomarker for Transmural Inflammation in Crohn's Disease.

Leucine-rich alpha-2 glycoprotein (LRG) is a newly studied biomarker for inflammatory diseases. This study aimed to investigate whether LRG can be used for evaluating transmural activity in patients with Crohn's disease (CD). We performed magnetic resonance enterography (MRE) in 227 consecutive patients with CD from June 2020 to August 2021. We prospectively compared MRE findings with clinical and laboratory data including LRG. MRE was evaluated using 2 validated scoring systems, and transmural inflammation was defined as having a maximum simplified magnetic resonance index of activity (sMaRIA) score of ≥4 and a 5-point classification score of ≥9, respectively. The correlation between LRG and the total MRE score showed a positive correlation ( r = 0.576 for the sMaRIA score, P < 0.01, and r = 0.633 for the 5-point score, P < 0.01). Serum concentrations of LRG significantly increased as MRE scores increased ( P < 0.01). The area under the curve of LRG for a sMaRIA score of ≥4 and a 5-point score of ≥9 was 0.845 and 0.869, respectively, which was significantly higher than that of CDAI ( P < 0.01) or C-reactive protein ( P < 0.01). LRG levels of ≥14 μg/mL had a 67% sensitivity and 90% specificity for a sMaRIA score of ≥4 and a 73% sensitivity and 89% specificity for a 5-point score of ≥9. Patients with high LRG levels were also strongly associated with CD-related hospitalization, surgery, and clinical relapse compared with those with low LRG levels ( P < 0.01 for all). LRG is a highly accurate serum biomarker for detecting transmural activity in patients with CD. Results need to be validated in further multicenter studies.

Serum Leucine-Rich α2 Glycoprotein: A Biomarker for Predicting the Presence of Ulcerative Colitis but Not Ulcerative Proctitis.

The serum level of leucine-rich α2 glycoprotein (LRG) is a biomarker for active ulcerative colitis (UC). We examined the serum level of LRG as a biomarker for predicting the presence of UC. Patients with persistent diarrhea and/or bloody stool with no history of UC were consecutively enrolled at their initial visit. Serum LRG measurement and colonoscopy with histology were performed on the same day. We enrolled 103 patients (69 men; median age, 45 years) with suspected UC; 66 patients were diagnosed with active UC (proctitis, n = 10; left-sided colitis, n = 26; and pancolitis, n = 30) based on endoscopic and histological criteria. Although the median LRG value in patients with proctitis was similar to that of patients with normal colonoscopic findings (8.5 vs. 8.6 mg/mL, p = 0.24), the median LRG values were significantly elevated in patients with left-sided colitis and pancolitis compared with those of patients with normal colonoscopy (13.6 or 18.0 vs. 8.6 mg/mL, p &lt; 0.0001). The LRG cut-off value of 10.8 μg/mL was derived from the ROC curve, showing 96% sensitivity and 97% specificity for active UC but not active proctitis. Using a cut-off value of 10.8 mg/mL serum, LRG could be a novel biomarker for predicting patients with active UC except for proctitis.

Leucine-rich a-2 glycoprotein as a potential biomarker of idiopathic multicentric Castleman disease with pulmonary involvement: a single-center case-control study from Japan.

BackgroundThere are no known biomarkers for monitoring disease activity in idiopathic multicentric Castleman disease (MCD) with pulmonary involvement. We investigated the utility of serum leucine-rich α2-glycoprotein levels, which reflects interleukin 6 independent inflammatory change, for monitoring disease activity in patients with idiopathic MCD with pulmonary involvement.MethodsWe retrospectively examined cases of idiopathic MCD diagnosed at Osaka University Hospital. The serum levels of leucine-rich α2-glycoprotein were compared between patients with idiopathic MCD and healthy controls. The difference in leucine-rich α2-glycoprotein levels before and after treatment (∆leucine-rich α2-glycoprotein) was evaluated with respect to the relationship with pulmonary function. In addition, the relationship between cytokine and chemokine profiles and the leucine-rich α2-glycoprotein concentration was investigated. The results were analyzed using pathway analysis.ResultsThe leucine-rich α2-glycoprotein concentrations were significantly higher in treatment-naïve patients (n=5) than in healthy controls (n=3) (P=0.035). Further, the ∆leucine-rich α2-glycoprotein concentration was significantly correlated with ∆ percent diffusing capacity of the lung for carbon monoxide (r=−0.88, P=0.049) and tended to correlate with ∆ percent vital capacity (r=−0.68, P=0.21) although the difference was not significant for the latter association. The concentrations of chemokines and cytokines, such as CXCL9, CXCL11, CXCL1, and a proliferation-inducing ligand, were higher in the patient group than in the healthy control group. Enrichment analysis indicated that leucine-rich α2-glycoprotein could be elevated via the upregulation of chemokines in patients with idiopathic MCD using these parameters.ConclusionsLeucine-rich a2-glycoprotein may be useful for monitoring disease activity in patients with idiopathic MCD with pulmonary involvement.

Serum Leucine-Rich Alpha-2 Glycoprotein in Quiescent Crohn's Disease as a Potential Surrogate Marker for Small-Bowel Ulceration detected by Capsule Endoscopy.

Background: Small bowel (SB) lesions in quiescent Crohn’s disease (CD) are sometimes not identified by clinical activity or existing markers. We investigated the usefulness of a novel biomarker, leucine-rich α2-glycoprotein (LRG), for screening for the presence of SB ulcerative lesions detected by small-bowel capsule endoscopy (SBCE). Methods: We examined patients with a Crohn’s Disease Activity Index (CDAI) value < 150 and a C-reactive protein (CRP) value < 0.5 mg/dL with SB or SB colonic CD. The presence of small-bowel ulcerative lesions (≥0.5 cm) was grouped by SBCE results, and we then compared the groups’ LRG value to establish a cutoff value for screening for the presence of lesions. Results: In 40 patients with CD, the LRG values differed significantly between the patients with and without SB ulcerative lesions (Ul + 14.1 (2.1–16.5) μg/mL vs. Ul − 12.3 (9.3–13.5) μg/mL; p = 0.0105). The respective cutoff LRG values for the presence of SB ulcerative lesions was 14 μg/mL (areas under the ROC curve 0.77), with sensitivity 63.6%, specificity 82.8%, positive predictive values 58.3%, negative predictive values 85.7%, and accuracy 78%. Conclusion: These results indicate that LRG may be useful in predicting the presence of SB inflammation associated in patients with CD with CRP < 0.5 mg/dL and CDAI < 150, and in selecting patients for SBCE.

The involvement of leucine-rich α-2 glycoprotein in the progression of skin and lung fibrosis in bleomycin-induced systemic sclerosis model

Objective Systemc sclerosis (SSc) is an autoimmune disorder characterized by fibrosis of the skin and internal organs. Recently, it has been shown that leucine-rich α-2 glycoprotein (LRG) functions as a modulator of transforming growth factor-β (TGF-β) signaling in fibrosis. We aimed to characterize the effect of LRG in SSc model and SSc patients. Methods Histological analysis was performed on LRG knockout (KO) and wild type (WT) mouse in the skin and the lung after bleomycin administration. Serum LRG levels were measured during the injection period. Gene expression analysis of the skin and lung tissue from LRG KO and WT mice was performed. In addition, serum LRG levels were determined in SSc patients and healthy controls. Results LRG KO mice display an inhibition of fibrosis in the skin in association with a decrease of dermal thickness, collagen deposition, and phospho-Smad3 expression after bleomycin. Serum LRG concentration significantly increased in WT mice after bleomycin. There was also a suppression of inflammation and fibrosis in the LRG KO mouse lung indicated by a reduction of lung weight, collagen content, and phospho-Smad3 expression after bleomycin. Gene expressions of TGF-β and Smad2/3 were significantly reduced in LRG KO mice. Serum LRG levels in SSc patients were significantly higher than those in controls. Conclusion LRG promotes fibrotic processes in SSc model through TGF-β-Smad3 signaling, and LRG can be a biomarker for SSc in humans and also a potential therapeutic target for SSc.