Relevance of Biomarkers in Serum vs. Synovial Fluid in Patients with Knee Osteoarthritis

The association between structural changes and pain sensation in osteoarthritis (OA) remains unclear. Joint deterioration in OA leads to the release of protein fragments that can either systemically (serum) or locally (synovial fluid; SF) be targeted as biomarkers and describe structural changes and potentially pain. Biomarkers of collagen type I (C1M), type II (C2M), type III (C3M), type X (C10C), and aggrecan (ARGS) degradation were measured in the serum and SF of knee OA patients. Spearman’s rank correlation was used to assess the correlation of the biomarkers’ levels between serum and SF. Linear regression adjusted for confounders was used to evaluate the associations between the biomarkers’ levels and clinical outcomes. The serum C1M levels were negatively associated with subchondral bone density. The serum C2M levels were negatively associated with KL grade and positively associated with minimum joint space width (minJSW). The C10C levels in SF were negatively associated with minJSW and positively associated with KL grade and osteophyte area. Lastly, the serum C2M and C3M levels were negatively associated with pain outcomes. Most of the biomarkers seemed to mainly be associated with structural outcomes. The overall biomarkers of extracellular matrix (ECM) remodeling in serum and SF may provide different information and reflect different pathogenic processes

Predicted and actual 2-year structural and pain progression in the IMI-APPROACH knee osteoarthritis cohort

ClinicalTrials.gov, https://clinicaltrials.gov, NCT03883568[Abstract] Objectives: The IMI-APPROACH knee osteoarthritis study used machine learning (ML) to predict structural and/or pain progression, expressed by a structural (S) and pain (P) predicted-progression score, to select patients from existing cohorts. This study evaluates the actual 2-year progression within the IMI-APPROACH, in relation to the predicted-progression scores. Methods: Actual structural progression was measured using minimum joint space width (minJSW). Actual pain (progression) was evaluated using the Knee injury and Osteoarthritis Outcomes Score (KOOS) pain questionnaire. Progression was presented as actual change (Δ) after 2 years, and as progression over 2 years based on a per patient fitted regression line using 0, 0.5, 1 and 2-year values. Differences in predicted-progression scores between actual progressors and non-progressors were evaluated. Receiver operating characteristic (ROC) curves were constructed and corresponding area under the curve (AUC) reported. Using Youden's index, optimal cut-offs were chosen to enable evaluation of both predicted-progression scores to identify actual progressors. Results: Actual structural progressors were initially assigned higher S predicted-progression scores compared with structural non-progressors. Likewise, actual pain progressors were assigned higher P predicted-progression scores compared with pain non-progressors. The AUC-ROC for the S predicted-progression score to identify actual structural progressors was poor (0.612 and 0.599 for Δ and regression minJSW, respectively). The AUC-ROC for the P predicted-progression score to identify actual pain progressors were good (0.817 and 0.830 for Δ and regression KOOS pain, respectively). Conclusion: The S and P predicted-progression scores as provided by the ML models developed and used for the selection of IMI-APPROACH patients were to some degree able to distinguish between actual progressors and non-progressors

Biomarkers of neutrophil activity and extracellular matrix turnover predict long-term response to vedolizumab in patients with Crohn's disease

Background Crohn‘s disease (CD) is a form of inflammatory bowel disease characterized by high infiltration of immune cells into the intestinal tissue, resulting in increased proteolytic mediated extracellular matrix (ECM) remodeling. Disease management has improved with the use of biologics such as vedolizumab (VEDO). However, considering the high rate of primary non-response to VEDO, there is an unmet need for predictive serum biomarkers capable of determining response to treatment prior to its initiation. This study investigated whether biomarkers of neutrophil activity, mucosal damage, and ECM remodeling could serve as non-invasive tools for predicting long-term response to VEDO in patients with CD. Methods Serum biomarkers of human neutrophil elastase (HNE)-derived fragment of calprotectin (CPa9-HNE [serum calprotectin]) and matrix metalloproteinase (MMP)-derived fragments of type I (C1M), III (C3M), IV (C4M), type III collagen formation (PRO-C3), basement membrane turnover (PRO-C4) and T-cell activity (C4G), were measured using protein fingerprint assays in patients with CD (n=32) before VEDO therapy initiation. The ratio C4M/C4G (myeloid/lymphoid mediated degradation) was computed. Long-term response was defined as the continuation of treatment beyond one year after the start of therapy. Baseline biomarker levels were compared between responders and non-responders using Mann-Whitney U-tests, and area under the curve (AUC) values were generated using receiver operating characteristics (ROC) statistics. Biomarker levels were divided into tertiles and chi-square tests were used to investigate the relationship between tertiles and response proportions. Results Biomarkers CPa9-HNE, C1M, C3M, C4M, PRO-C3, C3M/PRO-C3, and C4M/C4G were significantly increased at baseline in non-responders compared with responders (all P<0.05). All markers were able to predict response to VEDO at baseline (AUC [95% CI]: CPa9-HNE 0.81 [0.66–0.96]; C1M 0.85 [0.75–0.98]; C3M 0.79 [0.62–0.95]; C4M 0.77 [0.6–0.93]; C3M/PRO-C3 0.78 [0.6–0.95]; C4M/C4G 0.74 [0.56–0.92] all P<0.05). Proportions of long-term VEDO users were highest in the first tertiles for all the markers (73–91%) and decreased in a concentration-dependent manner across the second and third tertiles, indicating that patients with the lowest concentrations of these markers less frequently discontinued treatment at one year after initiation (Figure 1). Conclusion Baseline levels of serum biomarkers for neutrophil activity (CPa9-HNE [serum calprotectin]) and mucosal damage (C1M, C3M, C4M, C4G, PRO-C4, and PRO-C3) could predict long-term response to VEDO in patients with CD. Therefore, these biomarkers could aid in early decision making concerning treatment with vedolizumab in patients with CD

Type I collagen degradation fragments (C1M) and human neutrophil elastase-derived fragments of calprotectin (CPa9-HNE) reflect biochemical and endoscopic disease activity in patients with Inflammatory Bowel Disease

Background Crohn’s disease (CD) and ulcerative colitis (UC) are characterized by intestinal inflammation and increased extracellular matrix (ECM) remodeling, which are key pathophysiological mechanisms in patients with IBD and highly related to mucosal damage. Alterations in intestinal ECM turnover as well as macrophage and neutrophil activity may be reflected by secreted products that are released into the systemic circulation. In this study, we aimed to investigate associations between serum biomarkers of neutrophil activity (serum calprotectin) and collagen degradation (mucosal damage), and disease activity in patients with IBD. Methods Serological biomarkers of collagen formation (PRO-C3, PRO-C4, PRO-C6), matrix metalloproteinase (MMP)-mediated collagen degradation (C1M, C3M, C4M, C4G, C6Ma3) and intestinal inflammation (VICM [macrophage activity], human neutrophil elastase-derived fragment of calprotectin (CPa9-HNE [serum calprotectin, neutrophil activity]) were measured using Protein FingerPrint assay (PFA) technology in 100 patients with IBD (CD: n=44; UC: n=56). Biochemical disease activity was assessed using C-reactive protein (CRP) levels and available faecal calprotectin (FCal) levels. Endoscopic disease activity was determined using the Simple Endoscopic Score for CD (SES-CD) and Mayo endoscopic subscore for UC. Results C1M strongly associated with elevated CRP levels (defined as >5mg/L, P<0.001) in patients with IBD and significantly associated with faecal calprotectin levels in patients with UC (Spearman’s ρ=0.75, P<0.001). In patients with CD, C1M reasonably discriminated between patients with mild and moderate-to-severe endoscopic disease activity (AUC=0.73, P=0.01), whereas this discrimination was more subtle in patients with UC (AUC=0.68, P=0.08). CPa9-HNE levels were significantly increased in patients with elevated CRP levels (P=0.002 for both CD and UC) and associated best with faecal calprotectin levels in patients with CD compared with UC (CD: ρ=0.43, P=0.06; UC: ρ=0.20, P=0.45). Finally, CPa9-HNE levels were able to discriminate between mild and moderate-to-severe endoscopic disease activity in patients with CD (AUC=0.75, P<0.01). Conclusion C1M and CPa9-HNE levels associate with biochemical (CRP, FCal) and endoscopic disease activity in patients IBD, where C1M demonstrated higher accuracy in UC and CPa9-HNE appeared to be more useful in CD in this cohort. Therefore, C1M and CPa9-HNE could serve as surrogate biomarkers for the assessment of disease activity in patients with UC and CD, respectively. Our results should be validated in additional prospective, larger patient cohorts to corroborate these findings

Serological biomarkers of type VI and XXII collagen formation predict and monitor infliximab treatment response in patients with Crohn's disease

Background Crohn’s disease (CD) is a chronic inflammatory disease of the gastrointestinal (GI) tract characterized by excessive protease activity and extracellular matrix (ECM) remodeling. Although biologics such as TNF-α antibodies have improved the management of disease, up to 30–50% of patients still experience non-response to treatment. Biomarkers may be useful to improve therapeutic decision-making and monitor treatment response, thereby optimizing biological therapy and decreasing the risk of surgical intervention. This study assessed whether serological biomarkers of ECM turnover could monitor or predict response to TNF-α-antagonists in patients with and without surgical history. Methods Using protein fingerprint technology, serum biomarkers of type VI (PRO-C6) and XXII (PRO-C22) collagen formation were measured in 63 patients with CD undergoing infliximab (IFX) induction therapy. Disease activity was defined by a composite of the Harvey-Bradshaw Index (HBI) and physician’s global assessments (PGA). Response to treatment was defined as steroid-free remission (HBI<5) at week 14. Patients were stratified according to history of prior surgery. Patients with history of prior surgery (n=18) were 10 responders and 8 non-responders. Patients without history of prior surgery (n=45) were 40 responders and 5 non-responders. Differences in marker levels between groups were determined using Mann-Whitney U-tests. Area under the curve (AUC) values were generated using receiver operating characteristics (ROC) statistics. Results In patients with history of prior surgery, PRO-C22 was higher at baseline in responders than non-responders (P=0.004). At week 14, responders had higher levels of PRO-C6 than non-responders (P<0.05). Biomarkers PRO-C6 and PRO-C22 demonstrated predictive value at baseline (AUC [95% CI]: PRO-C6 0.78 [0.55–1.0], P=0.012; PRO-C22 0.90 [0.73–1.0], P<0.001). At week 14, PRO-C6 was also able to discriminate between responders and non-responders (AUC [95% CI]: 0.82 [0.54–1.0], P<0.01). No significant differences were observed in patients without history of prior surgery (Figure 1). Conclusion In patients with a history of prior surgery, higher baseline levels of PRO-C22 predict treatment response to IFX, whereas PRO-C6 levels were higher at week 14 after treatment initiation. These biomarkers demonstrated promising results in predicting response to anti-TNFα treatment, as well as separating responders from non-responders at week 14. Together, these markers could be used to predict and monitor treatment response to IFX in patients with CD with surgical history and may shed light on different profiles of ECM turnover. Future studies are warranted to further validate the potential utility of these biomarkers in larger patient cohorts