Serum levels of the N-terminal fragment of connective tissue growth factor is a novel biomarker for chronic pancreatitis

Chronic inflammation of the pancreas is considered to be one of the causes of pancreatic cancer. However, the diagnosis of chronic pancreatitis (CP) is very difficult in the pancreas, where biopsies are difficult to perform. The prevalence of CP is estimated to be many times more common than in patients with actual symptomatic CP. In recent years, abnormal cleavage of certain proteins has attracted attention as a biomarker for CP other than pancreatic enzymes. Connective tissue growth factor (CTGF) is one of the growth factors involved in tissue repair and other processes and is increased by stimulation of transforming growth factor-β, suggesting a relationship of CTGF with fibrosis. In this study, we measured the total length of CTGF in blood and N-terminal fragment CTGF in 48 cases of chronic pancreatitis, 64 cases of pancreatic cancer and 45 healthy volunteers (HV). Interestingly, we found that blood N-terminal fragment CTGF level was significantly increased in CP and pancreatic cancer patients. Multiple logistic regression analysis showed serum levels of N-terminal fragment CTGF, CRP and amylase were significant and independent variables for the differential diagnosis of CP from HV. Receiver operating characteristic analysis showed that area under the curve (AUC) value of serum N-terminal fragment CTGF level was 0.933, which can differentiate between CP and HV. Several factors would be involved in the increase in serum N-terminal fragment CTGF level. In conclusion, serum N-terminal fragment CTGF level is a promising new biomarker for CP.

Vitreous protein networks around ANG2 and VEGF in proliferative diabetic retinopathy and the differential effects of aflibercept versus bevacizumab pre-treatment

Extracellular signalling proteins interact in networks rather than in isolation. In this context we investigated vitreous protein levels, including placental growth factor (PlGF), angiopoietin-2 (ANG2) and vascular endothelial growth factor (VEGF), in patients with proliferative diabetic retinopathy (PDR) with variable disease severities, and after anti-VEGF pre-treatment. Vitreous samples of 112 consecutive patients undergoing vitrectomy for PDR and of 52 non-diabetic patients with macular holes as controls were studied. A subset of the PDR patients were treated with either aflibercept (AFB, n = 25) or bevacizumab (BVZ)/ranibizumab (RZB) (n = 13), before surgery. Antibody-based analysis of 35 proteins (growth factors and cytokines) showed a significant increase in expression levels of 27 proteins in PDR patients as compared to controls. In network analysis of co-regulated proteins, a strong correlation in expression levels between VEGF, PlGF, MCP1 and ANG2 was found, mostly clustered around ANG2. In the AFB treatment group, concentrations of several proteins were decreased, including VEGFR1, whereas interleukin 6 and 8 were increased as compared to untreated PDR patients. The observed differences in vitreous protein levels between the different treatments and untreated PDR patients may underlie differences in clinical outcomes in patients with PDR.

CCN2 (Cellular Communication Network factor 2) in the bone marrow microenvironment, normal and malignant hematopoiesis

CCN2, formerly termed Connective Tissue Growth Factor, is a protein belonging to the Cellular Communication Network (CCN)-family of secreted extracellular matrix-associated proteins. As a matricellular protein it is mainly considered to be active as a modifier of signaling activity of several different signaling pathways and as an orchestrator of their cross-talk. Furthermore, CCN2 and its fragments have been implicated in the regulation of a multitude of biological processes, including cell proliferation, differentiation, adhesion, migration, cell survival, apoptosis and the production of extracellular matrix products, as well as in more complex processes such as embryonic development, angiogenesis, chondrogenesis, osteogenesis, fibrosis, mechanotransduction and inflammation. Its function is complex and context dependent, depending on cell type, state of differentiation and microenvironmental context. CCN2 plays a role in many diseases, especially those associated with fibrosis, but has also been implicated in many different forms of cancer. In the bone marrow (BM), CCN2 is highly expressed in mesenchymal stem/stromal cells (MSCs). CCN2 is important for MSC function, supporting its proliferation, migration and differentiation. In addition, stromal CCN2 supports the maintenance and longtime survival of hematopoietic stem cells, and in the presence of interleukin 7, stimulates the differentiation of pro-B lymphocytes into pre-B lymphocytes. Overexpression of CCN2 is seen in the majority of B-acute lymphoblastic leukemias, especially in certain cytogenetic subgroups associated with poor outcome. In acute myeloid leukemia, CCN2 expression is increased in MSCs, which has been associated with leukemic engraftment in vivo. In this review, the complex function of CCN2 in the BM microenvironment and in normal as well as malignant hematopoiesis is discussed. In addition, an overview is given of data on the remaining CCN family members regarding normal and malignant hematopoiesis, having many similarities and some differences in their function.

Connective Tissue Growth Factor Neutralization Aggravates the Psoriasis Skin Lesion: The Analysis of Psoriasis Model Mice and Patients

Background

Connective tissue growth factor (CTGF) is a multifunctional cellular protein and playing a role as a central mediator in tissue remodeling and fibrosis. The physiological function of CTGF in psoriasis is unknown.

Objective

The purpose of this study was to investigate the function of CTGF in psoriasis using the established imiquimod (IMQ)-induced psoriasis murine model and psoriasis patients.

Methods

Anti-CTGF monoclonal antibody was applied to IMQ induced psoriasis mice and those skin were clinically, pathologically and immunologically analyzed. Additionally, CTGF expression was analyzes using skin samples and plasma from psoriasis patients.

Results

CTGF expression was observed in the dermis from both IMQ-induced psoriatic mice and psoriasis patients. CTGF inhibition using an anti-CTGF antibody slightly worsened IMQ-induced dermatitis. In addition, the increase of CTGF showed tendency to suppress the psoriatic dermatitis through inhibition of suprabasal cells proliferation and macrophage infiltration in the skin. CTGF was also detected significantly higher in plasma from psoriasis patients comparing with healthy control.

Conclusion

Our findings suggest that CTGF could contribute to the healing rather than the worsening of psoriasis skin lesions.

The diagnostic value of plasma N-terminal connective tissue growth factor levels in children with heart failure

OBJECTIVE

The aim of this study was to assess the diagnostic value of plasma N-terminal connective tissue growth factor in children with heart failure. Methods and results Plasma N-terminal connective tissue growth factor was determined in 61 children, including 41 children with heart failure, 20 children without heart failure, and 30 healthy volunteers. The correlations between plasma N-terminal connective tissue growth factor levels and clinical parameters were investigated. Moreover, the diagnostic value of N-terminal connective tissue growth factor levels was evaluated. Compared with healthy volunteers and children without heart failure, plasma N-terminal connective tissue growth factor levels were significantly elevated in those with heart failure (p0.05), but it obviously improved the ability of diagnosing heart failure in children, as demonstrated by the integrated discrimination improvement (6.2%, p=0.013) and net re-classification improvement (13.2%, p=0.017) indices.

CONCLUSIONS

Plasma N-terminal connective tissue growth factor is a promising diagnostic biomarker for heart failure in children.

Rapid hepatic clearance of full length CCN-2/CTGF: a putative role for LRP1-mediated endocytosis

CCN-2 (connective tissue growth factor; CTGF) is a key factor in fibrosis. Plasma CCN-2 has biomarker potential in numerous fibrotic disorders, but it is unknown which pathophysiological factors determine plasma CCN-2 levels. The proteolytic amino-terminal fragment of CCN-2 is primarily eliminated by the kidney. Here, we investigated elimination and distribution profiles of full length CCN-2 by intravenous administration of recombinant CCN-2 to rodents. After bolus injection in mice, we observed a large initial distribution volume (454 mL/kg) and a fast initial clearance (120 mL/kg/min). Immunosorbent assay and immunostaining showed that CCN-2 distributed mainly to the liver and was taken up by hepatocytes. Steady state clearance in rats, determined by continuous infusion of CCN-2, was fast (45 mL/kg/min). Renal CCN-2 clearance, determined by arterial and renal vein sampling, accounted for only 12 % of total clearance. Co-infusion of CCN-2 with receptor-associated protein (RAP), an antagonist of LDL-receptor family proteins, showed that RAP prolonged CCN-2 half-life and completely prevented CCN-2 internalization by hepatocytes. This suggests that hepatic uptake of CCN-2 is mediated by a RAP-sensitive mechanism most likely involving LRP1, a member of the LDL-receptor family involved in hepatic clearance of various plasma proteins. Surface plasmon resonance binding studies confirmed that CCN-2 is an LRP1 ligand. Co-infusion of CCN-2 with an excess of the heparan sulphate-binding protamine lowered the large initial distribution volume of CCN-2 by 88 % and reduced interstitial staining of CCN-2, suggesting binding of CCN-2 to heparan sulphate proteoglycans (HSPGs). Protamine did not affect clearance rate, indicating that RAP-sensitive clearance of CCN-2 is HSPG independent. In conclusion, unlike its amino-terminal fragment which is cleared by the kidney, full length CCN-2 is primarily eliminated by the liver via a fast RAP-sensitive, probably LRP1-dependent pathway.

Elevated Plasma Connective Tissue Growth Factor Levels in Children with Pulmonary Arterial Hypertension Associated with Congenital Heart Disease

We aimed to investigate plasma connective tissue growth factor (CTGF) levels in pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD) (PAH-CHD) in children and the relationships of CTGF with hemodynamic parameters. Plasma CTGF levels were calculated in 30 children with CHD, 30 children with PAH-CHD and 25 health volunteers, using the subtraction method. Cardiac catheterization was performed to measure clinical hemodynamic parameters. Plasma CTGF levels were significantly higher in PAH-CHD than in those with CHD and health volunteers (p < 0.01). In cyanotic PAH-CHD, plasma CTGF levels were significantly elevated compared with acyanotic PAH-CHD in the same group (p < 0.05). Plasma CTGF levels showed positive correlation with B-type natriuretic peptide (BNP) in PAH-CHD (r = 0.475, p < 0.01), while oxygen saturation was inversely related to plasma CTGF levels (r = -0.436, p < 0.05). There was no correlation between CTGF and hemodynamic parameters. Even though the addition of CTGF to BNP did not significantly increase area under curve for diagnosis of PAH-CHD compared with BNP alone (p > 0.05), it revealed a moderately better specificity, positive predictive value and positive likelihood ratio than BNP alone. Plasma CTGF levels could be a promising diagnostic biomarker for PAH-CHD in children.

Elevated Urinary Connective Tissue Growth Factor in Diabetic Nephropathy Is Caused by Local Production and Tubular Dysfunction

Connective tissue growth factor (CTGF; CCN2) plays a role in the development of diabetic nephropathy (DN). Urinary CTGF (uCTGF) is elevated in DN patients and has been proposed as a biomarker for disease progression, but it is unknown which pathophysiological factors contribute to elevated uCTGF. We studied renal handling of CTGF by infusion of recombinant CTGF in diabetic mice. In addition, uCTGF was measured in type 1 DN patients and compared with glomerular and tubular dysfunction and damage markers. In diabetic mice, uCTGF was increased and fractional excretion (FE) of recombinant CTGF was substantially elevated indicating reduced tubular reabsorption. FE of recombinant CTGF correlated with excretion of endogenous CTGF. CTGF mRNA was mainly localized in glomeruli and medullary tubules. Comparison of FE of endogenous and recombinant CTGF indicated that 60% of uCTGF had a direct renal source, while 40% originated from plasma CTGF. In DN patients, uCTGF was independently associated with markers of proximal and distal tubular dysfunction and damage. In conclusion, uCTGF in DN is elevated as a result of both increased local production and reduced reabsorption due to tubular dysfunction. We submit that uCTGF is a biomarker reflecting both glomerular and tubulointerstitial hallmarks of diabetic kidney disease.

Plasma connective tissue growth factor levels as potential biomarkers of airway obstruction in patients with asthma

BACKGROUND

Bronchial asthma is a chronic inflammatory disorder characterized by airway hyperresponsiveness and airflow limitation. Connective tissue growth factor (CTGF), one of the key profibrotic factors associated with transforming growth factor β, may be related to airway remodeling in asthma. However, no data are available on the association between plasma CTGF levels and clinical and physiologic parameters in patients with asthma. Recently, we developed a novel subtraction method for determination of plasma CTGF levels.

OBJECTIVE

To investigate the utility of plasma CTGF level as a surrogate biomarker in asthma.

METHODS

Plasma CTGF levels were measured in 67 patients with stable asthma and 81 healthy volunteers, using the subtraction method. We evaluated correlations between plasma CTGF levels and clinical and physiologic parameters in patients with asthma.

RESULTS

Plasma CTGF levels were higher in patients with asthma than in healthy volunteers. Asthmatic patients with a percentage of predicted forced expiratory volume in 1 second (FEV1) less than 80% had significantly higher levels of plasma CTGF than those with a percentage of predicted FEV1 of 80% or more. In patients with asthma, plasma CTGF levels had significantly negative correlations with forced vital capacity (FVC), FEV1, percentage of predicted FEV1, FEV1/FVC ratio, forced expiratory flow at 50% of the FVC (FEF50%), percentage of predicted FEF50%, forced expiratory flow at 75% of the FVC (FEF75%), and percentage of predicted FEF75%, parameters that reflect the degree of airway obstruction. Plasma CTGF levels were negatively correlated with Asthma Control Test scores, a patient-based index of clinical control of asthma.

CONCLUSION

Plasma CTGF may be a potential biomarker for stable asthma when evaluating the degree of persistent airway obstruction.

TRIAL REGISTRATION

umin.ac.jp/ctr Identifier: UMIN000013081.

Effect of GFR on plasma N-terminal connective tissue growth factor (CTGF) concentrations

BACKGROUND

Connective tissue growth factor (CTGF) has a key role in the pathogenesis of renal and cardiac fibrosis. Its amino-terminal fragment (N-CTGF), the predominant form of CTGF detected in plasma, has a molecular weight in the middle molecular range (18 kDa). However, it is unknown whether N-CTGF is a uremic retention solute that accumulates in chronic kidney disease (CKD) due to decreased renal clearance and whether it can be removed by hemodiafiltration.

STUDY DESIGN

4 observational studies in patients and 2 pharmacokinetic studies in rodents.

SETTING & PARTICIPANTS

4 single-center studies. First study (cross-sectional): 88 patients with CKD not receiving kidney replacement therapy. Second study (cross-sectional): 23 patients with end-stage kidney disease undergoing low-flux hemodialysis. Third study: 9 kidney transplant recipients before and 6 months after transplant. Fourth study: 11 low-flux hemodialysis patients and 12 hemodiafiltration patients before and after one dialysis session.

PREDICTOR

First, second, and third study: (residual) glomerular filtration rate (GFR). Fourth study: dialysis modality.

OUTCOMES & MEASUREMENTS

Plasma (N-)CTGF concentrations, measured by enzyme-linked immunosorbent assay.

RESULTS

In patients with CKD, we observed an independent association between plasma CTGF level and estimated GFR (β = -0.72; P < 0.001). In patients with end-stage kidney disease, plasma CTGF level correlated independently with residual kidney function (β = -0.55; P = 0.046). Successful kidney transplant resulted in a decrease in plasma CTGF level (P = 0.008) proportional to the increase in estimated GFR. Plasma CTGF was not removed by low-flux hemodialysis, whereas it was decreased by 68% by a single hemodiafiltration session (P < 0.001). Pharmacokinetic studies in nonuremic rodents confirmed that renal clearance is the major elimination route of N-CTGF.

LIMITATIONS

Observational studies with limited number of patients. Fourth study: nonrandomized, evaluation of the effect of one session; randomized longitudinal study is warranted.

CONCLUSION

Plasma (N-)CTGF is eliminated predominantly by the kidney, accumulates in CKD, and is decreased substantially by a single hemodiafiltration session.

Connective tissue growth factor (CTGF/CCN2) ELISA: a novel tool for monitoring fibrosis

BACKGROUND

Connective tissue growth factor (CTGF) has been identified as a key factor in the pathogenesis of diseases with significant fibrosis-related complications such as hepatitis, diabetes and renal transplantation. Increasing evidence shows that CTGF levels in plasma, serum and urine have promising biomarker applicability in these disorders.

OBJECTIVE

To present an overview of current knowledge on CTGF in various patient populations and the technical aspects of CTGF measurement by enzyme-linked immunosorbent assay (ELISA).

METHOD

We performed a comprehensive literature search by using electronic bibliographic databases.

CONCLUSION

CTGF is associated with disease severity parameters and outcome in fibrotic disease and may have diagnostic and prognostic values. However, CTGF ELISA needs standardization.

Plasma CCN2 (connective tissue growth factor; CTGF) is a potential biomarker in idiopathic pulmonary fibrosis (IPF)

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive and fatal pulmonary fibrotic disease and useful biomarkers are required to diagnose and predict disease activity. CCN2 (connective tissue growth factor; CTGF) has been reported as one of the key profibrotic factors associated with transforming growth factor-β (TGF-β), and its assay has potential as a non-invasive measure in various fibrotic diseases. Recently, we developed a new subtraction method for determination of plasma CCN2 levels. We examined the utility of plasma CCN2 levels as a surrogate marker in IPF.

METHODS

Plasma CCN2 levels were calculated in 33 patients with IPF, 14 patients with non-IPF idiopathic interstitial pneumonias (IIPs) and 101 healthy volunteers by sandwich enzyme-linked immunosorbent assay (ELISA) using specific monoclonal antibodies for two distinct epitopes of human CCN2. We evaluated the utility of plasma CCN2 levels by comparison with clinical parameters.

RESULTS

Plasma CCN2 levels were significantly higher in patients with IPF than in those with non-IPF IIPs and healthy volunteers. Importantly, plasma CCN2 levels showed significantly negative correlation with 6-month change of forced vital capacity (FVC) in patients with IPF.

CONCLUSIONS

Plasma CCN2 is a potential biomarker for IPF.