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Objectives: Ankylosing spondylitis (AS) is a chronic inflammation of the spine and the sacroiliac joints. Current markers of inflammation, such as C-reactive protein (CRP), are reflecting the production of an acute phase reactant rather than tissue specific inflammation, but the use of CRP as a diagnostic and prognostic marker for AS has not provided the sought accuracy and specificity. We hypothesized that local enzymatic activity in the disease-affected tissue, which is associated with extensive tissue turnover may, by cleavage, modify the CRP produced in the liver. These cleavage products may provide additional information on systemic inflammation as compared to that of full-length CRP. We investigated whether these CRP degradation products would provide additional diagnostic value in AS patients compared to full-length CRP., Methods: CRP fragments were identified by mass-spectrometry. Two fragments were selected for ELISA development. One assay exclusively identified a matrix metalloproteinase (MMP) generated fragment, CRP-MMP, whereas the other assay identified a cathepsin generated fragment, CRP-CAT. Full-length CRP, CRP-MMP and CRP-CAT were measured in serum samples from 40 AS patients and 40 sex- and age-matched controls., Results: Full-length CRP was not elevated in AS patients compared to controls, whereas CRP-MMP was elevated by 25% (p<0.001) and CRP-CAT by 50% (p<0.0001). The Area Under Curve of the Receiver-Operator Characteristic curve of CRP-CAT was the highest with 77%., Conclusions: MMP and cathepsin degraded CRP provided more discriminative diagnostic potential compared to that of full-length CRP in this current study. These data suggest that different pools of CRP may provide insight into the inflammation processes in AS.

Objectives: Type V collagen has been demonstrated to control fibril formation. The aim of this study was to develop an ELISA capable of detecting a fragment of type V collagen generated by MMP-2/9 and to evaluate the assay as biomarker for ankylosing spondylitis (AS)., Design and Methods: A fragment unique to type V collagen and generated by both MMP-2/9 cleaved at the amino acid position 1317 (C5M) was selected for ELISA development. 40 AS patients and 40 age-matched controls were evaluated., Results: An ELISA detecting C5M with inter- and intra-assay variations of 9.1% and 4.4% was developed. C5M levels were significantly higher in AS patients compared to controls, 229% (p<0.0001). The diagnostic AUC was 83%., Conclusions: This ELISA is the first for detecting type V collagen degradation. AS patients had highly elevated levels of MMP mediated type V collagen degradation. The prognostic and diagnostic values need to be further investigated in additional clinical settings., (Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)

Objectives: The present study describes two newly developed N-terminal pro-peptides of collagen type I (PINP) competitive enzyme-linked immunosorbent assays (ELISAs) for the assessment of corresponding PINP epitopes in the rat- and human species., Methods: Monoclonal antibodies were raised against corresponding rat and human PINP sequences and competitive assays were developed for each species. They were evaluated in relevant pre-clinical or clinical studies., Results: The antibody characterizations indicated that PINP indeed was recognized. Technical robust assays were obtained. Rat PINP and tALP showed similar patterns in the gold standard osteoporosis rat ovariectomized (OVX) model. No liver contribution was observed in the liver fibrosis rat bile duct ligation model (BDL). In an osteoporosis study, the human serum PINP levels were significantly decreased after ibandronate treatment compared to placebo., Conclusions: The two corresponding PINP assays were specific and these bone turnover markers may improve translational science for the evaluation for bone-related diseases., (Copyright © 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)

Background: Decorin is one of the most abundant proteoglycans of the extracellular matrix and is mainly secreted and deposited in the interstitial matrix by fibroblasts where it plays an important role in collagen turnover and tissue homeostasis. Degradation of decorin might disturb normal tissue homeostasis contributing to extracellular matrix remodeling diseases. Here, we present the development and validation of a competitive enzyme-linked immunosorbent assay (ELISA) quantifying a specific fragment of degraded decorin, which has potential as a novel non-invasive serum biomarker for fibrotic lung disorders.Methods: A fragment of decorin cleaved in vitro using human articular cartilage was identified by mass-spectrometry (MS/MS). Monoclonal antibodies were raised against the neo-epitope of the cleaved decorin fragment and a competitive ELISA assay (DCN-CS) was developed. The assay was evaluated by determining the inter- and intra-assay precision, dilution recovery, accuracy, analyte stability and interference. Serum levels were assessed in lung cancer patients, patients with idiopathic pulmonary fibrosis (IPF), patients with chronic obstructive pulmonary disease (COPD) and healthy controls.Results: The DCN-CS ELISA was technically robust and was specific for decorin cleaved by cathepsin-S. DCN-CS was elevated in lung cancer patients (p < 0.0001) and IPF patients (p < 0.001) when compared to healthy controls. The diagnostic power for differentiating lung cancer patients and IPF patients from healthy controls was 0.96 and 0.77, respectively.Conclusion: Cathepsin-S degraded decorin could be quantified in serum using the DCN-CS competitive ELISA. The clinical data indicated that degradation of decorin by cathepsin-S is an important part of the pathology of lung cancer and IPF. [ABSTRACT FROM AUTHOR]

Background and Aims: Progressive fibrosis increases hepatic resistance and causes portal hypertension with complications. During progressive fibrosis remodeling and deposition of collagens and elastin occur. Elastin remodeling is crucially involved in fibrosis progression in animal models and human data. This study investigated the association of circulating elastin with the clinical outcome in cirrhotic patients with severe portal hypertension receiving transjugular intrahepatic porto-systemic shunt (TIPS).Methods: We analyzed portal and hepatic venous samples of 110 cirrhotic patients obtained at TIPS insertion and 2 weeks later. The circulating levels of elastin fragments (ELM) were determined using specific monoclonal ELISA. The relationship of ELM with clinical short-time follow-up and long-term outcome was investigated.Results: Circulating levels of ELM showed a gradient across the liver before TIPS with higher levels in the hepatic vein. Interestingly, the circulating ELM levels remained unchanged after TIPS. The circulating levels of ELM in portal and hepatic veins correlated with platelet counts and inversely with serum sodium. Hepatic venous levels of ELM were higher in CHILD C compared to CHILD A and B and were associated with the presence of ascites. Patients with high levels of ELM in the hepatic veins before TIPS showed poorer survival. In multivariate analysis ELM levels in the hepatic veins and MELD were independent predictors of mortality in these patients.Conclusion: This study demonstrated that circulating levels of ELM are not associated with hemodynamic changes, but might reflect fibrosis remodeling and predict survival in patients with severe portal hypertension receiving TIPS independently of MELD. [ABSTRACT FROM AUTHOR]