Collagen turnover is associated with cardiovascular autonomic and peripheral neuropathy in type 1 diabetes: novel pathophysiological mechanism?

BACKGROUND: Diabetic cardiovascular autonomic neuropathy (CAN) and distal symmetrical polyneuropathy (DSPN) are severe diabetic complications. Collagen type VI (COL6) and III (COL3) have been associated with nerve function. We investigated if markers of COL6 formation (PRO-C6) and COL3 degradation (C3M) were associated with neuropathy in people with type 1 diabetes (T1D). METHODS: In a cross-sectional study including 300 people with T1D, serum and urine PRO-C6 and C3M were obtained. CAN was assessed by cardiovascular reflex tests: heart rate response to deep breathing (E/I ratio), to standing (30/15 ratio) and to the Valsalva maneuver (VM). Two or three pathological CARTs constituted CAN. DSPN was assessed by biothesiometry. Symmetrical vibration sensation threshold above 25 V constituted DSPN. RESULTS: Participants were (mean (SD)) 55.7 (9.3) years, 51% were males, diabetes duration was 40.0 (8.9) years, HbA1c was 63 (11 mmol/mol, (median (IQR)) serum PRO-C6 was 7.8 (6.2;11.0) ng/ml and C3M 8.3 (7.1;10.0) ng/ml. CAN and DSPN were diagnosed in 34% and 43% of participants, respectively. In models adjusted for relevant confounders a doubling of serum PRO-C6, was significantly associated with odds ratio > 2 for CAN and > 1 for DSPN, respectively. Significance was retained after additional adjustments for eGFR only for CAN. Higher serum C3M was associated with presence of CAN, but not after adjustment for eGFR. C3M was not associated with DSPN. Urine PRO-C6 analyses indicated similar associations. CONCLUSIONS: Results show previously undescribed associations between markers of collagen turnover and risk of CAN and to a lesser degree DSPN in T1D.

Are fatty acids associated with disease activity and biomarkers in patients with psoriatic arthritis? Data from a multicenter clinical trial.

The pathogenesis of psoriatic arthritis (PsA) involves inflammation and bone and soft tissue turnover. Dietary fatty acids have previously been associated with pro-inflammatory effects induced by saturated fatty acids (SFA) and anti-inflammatory effects achieved by at least some polyunsaturated fatty acids (PUFA). The aim of the study was to investigate the correlations between the content of fatty acids in granulocytes and clinical and biochemical markers of PsA. A total of 140 patients with PsA were included. Skin and joint disease activity were assessed. Fatty acid composition in granulocytes was determined by gas chromatography. Competitive enzyme-linked immunosorbent assays were used to assess bone and soft tissue turnover. The content of SFA, n-6 PUFA or n-3 PUFA in granulocytes was not associated with disease activity. Marine n-3 PUFA was significantly positively correlated with collagen degradation. In contrast, n-6 PUFA was significantly positively correlated with collagen formation and negatively correlated with collagen degradation. However, the correlations were all weak. No association was found between the content of fatty acids in granulocytes and disease activity in this population of patients with PsA. The correlation between fatty acids and biomarkers of bone and soft tissue turnover needs further investigation.

Bone phenotypes in rheumatology - there is more to bone than just bone.

Osteoarthritis, rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis, all have one clear common denominator; an altered turnover of bone. However, this may be more complex than a simple change in bone matrix and mineral turnover. While these diseases share a common tissue axis, their manifestations in the area of pathology are highly diverse, ranging from sclerosis to erosion of bone in different regions. The management of these diseases will benefit from a deeper understanding of the local versus systemic effects, the relation to the equilibrium of the bone balance (i.e., bone formation versus bone resorption), and the physiological and pathophysiological phenotypes of the cells involved (e.g., osteoblasts, osteoclasts, osteocytes and chondrocytes). For example, the process of endochondral bone formation in chondrocytes occurs exists during skeletal development and healthy conditions, but also in pathological conditions. This review focuses on the complex molecular and cellular taxonomy of bone in the context of rheumatological diseases that alter bone matrix composition and maintenance, giving rise to different bone turnover phenotypes, and how biomarkers (biochemical markers) can be applied to potentially describe specific bone phenotypic tissue profiles.

A non-invasive biomarker of type III collagen degradation reflects ischaemia reperfusion injury in rats.

BACKGROUND: Maintenance of kidney function in kidney allografts remains a challenge, as the allograft often progressively develops fibrosis after kidney transplantation. Fibrosis is caused by the accumulation of extracellular matrix proteins like type I and III collagen (COL I and III) that replace the functional tissue. We assessed the concentrations of a neo-epitope fragment of COL III generated by matrix metalloproteinase-9 cleavage (C3M) in two rat models resembling the ischaemic injury taking place following kidney transplantation. METHODS: We measured C3M in urine (U-C3M) and plasma (P-C3M) samples of rats subjected to unilateral nephrectomy followed by sham operation (NTx) or ischaemia reperfusion injury (NTxIRI) as well as in rats subjected to bilateral ischaemia reperfusion injury (BiIRI). Levels of U-C3M were normalized to urinary creatinine and were correlated to plasma creatinine, blood urea nitrogen, messenger ribonucleic acid (mRNA) of markers of kidney injury, and mRNA and protein levels of markers of tissue repair and fibrosis. RESULTS: Levels of U-C3M were significantly elevated 7 days after ischaemia reperfusion in the NTxIRI. BiIRI animals showed higher levels of U-C3M after 7 and 14 days of reperfusion but not at 21 days. P-C3M did not change in any of the models. There was a significant correlation between U-C3M and mRNA levels of fibronectin, COL I alpha 1 chain (COL Ia1) and neutrophil gelatinase-associated lipocalin (NGAL), and protein levels of alpha smooth muscle actin (αSMA), fibronectin and COL III in NTxIRI but not in NTx animals. Levels of U-C3M increased significantly in the BiIRI animals subsequent to reperfusion, and mirrored the histological alterations. Furthermore, U-C3M was associated with the extent of fibrosis, and remained elevated even after plasma creatinine levels decreased. CONCLUSIONS: These results demonstrate that degradation of COL III increases after ischaemia reperfusion injury, and that U-C3M may be a non-invasive marker of tissue repair and fibrosis in the ischaemic kidney.

Assessment of extracellular matrix-related biomarkers in patients with lower extremity artery disease.

BACKGROUND: The prevalence of lower extremity artery disease (LEAD) is high (20%-25%) in the population older than 65 years, but patients are seldom identified until the disease is advanced. Circulating markers of disease activity might provide patients with a key opportunity for timely treatment. We tested the hypothesis that measuring blood-specific fragments generated during degradation of the extracellular matrix (ECM) could provide further insight into the pathophysiologic mechanism of arterial remodeling. METHODS: The protein profile of diseased arteries from patients undergoing infrainguinal limb revascularization was assessed by a liquid chromatography and tandem mass spectrometry, nontargeted proteomic approach. The information retrieved was the basis for measurement of neoepitope fragments of ECM proteins in the blood of 195 consecutive patients with LEAD by specific enzyme-linked immunosorbent assays. RESULTS: Histologic and proteomic analyses confirmed the structural disorganization of affected arteries. Fourteen of 81 proteins were identified as differentially expressed in diseased arteries with respect to healthy tissues. Most of them were related to ECM components, and the difference in expression was used in multivariate analyses to establish that severe arterial lesions in LEAD patients have a specific proteome. Analysis of neoepitope fragments in blood revealed that fragments of versican and collagen type IV, alone or in combination, segregated patients with mild to moderate symptoms (intermittent claudication, Fontaine I-II) from those with severe LEAD (critical limb ischemia, Fontaine III-IV). CONCLUSIONS: We propose noninvasive candidate biomarkers with the ability to be clinically useful across the LEAD spectrum.

Investigating protease-mediated peptides of inflammation and tissue remodeling as biomarkers associated with flares in psoriatic arthritis.

BACKGROUND: Psoriatic arthritis (PsA) is an inflammatory arthritis associated with psoriasis. PsA disease involves flares, which are associated with increased joint inflammation and tissue remodeling. There is a need for identifying biomarkers related to PsA disease activity and flares to improve the management of PsA patients and decrease flares. The tissue turnover imbalance that occurs during the inflammatory and fibro-proliferative processes during flares leads to an increased degradation and/or reorganization of the extracellular matrix (ECM), where increased proteolysis plays a key role. Hence, protease-mediated fragments of inflammatory and tissue-remodeling components could be used as markers reflecting flares in PsA patients. METHODS: A broad panel of protease-mediated biomarkers reflecting inflammation and tissue remodeling was measured in serum and synovial fluid (SF) obtained from PsA patients experiencing flares (acutely swollen joint[s], PsA-flare). In serum, biomarker levels assessed in PsA-flare patients were compared to controls and in early-diagnosed PsA patients not experiencing flares (referred to as PsA without flare). Furthermore, the biomarker levels assessed in SF from PsA-flare patients were compared to the levels in SF of osteoarthritis (OA) patients. RESULTS: In serum, levels of the PRO-C3 and C3M, reflecting formation and degradation of the interstitial matrix, were found significantly elevated in PsA-flare compared to controls and PsA without flare. The remodeling marker of the basement membrane, PRO-C4, was significantly elevated in PsA-flare compared to PsA without flare. The inflammation and immune cell activity related markers, CRPM, VICM, and CPa9-HNE were significantly elevated in PsA-flare patients compared to controls and PsA without flare. In addition, VICM (AUC = 0.71), CPa9-HNE (AUC = 0.89), CRPM (AUC = 0.76), and PRO-C3 (AUC = 0.86) showed good discriminatory performance for separating PsA-flare from PsA without flare. In SF, the macrophage activity marker, VICM, was significantly elevated whereas the type II collagen formation marker, PRO-C2, was significantly reduced in the PsA-flare compared to OA. The combination of five serum markers reflecting type III and IV collagen degradation (C3M and C4M, respectively), type III and VI collagen formation (PRO-C3 and PRO-C6, respectively), and neutrophil activity (CPa9-HNE) showed an excellent discriminatory performance (AUC = 0.98) for separating PsA-flare from PsA without flares. CONCLUSIONS: The serum biomarker panel of C3M, C4M, PRO-C3, PRO-C6, and CPa9-HNE reflecting synovitis, enthesitis, and neutrophil activity may serve as novel tool for quantitatively monitoring flares in PsA patients.

Biomarkers of systemic inflammation are associated with disease severity and metabolic syndrome in patients with hidradenitis suppurativa.

Background: Biomarkers associated with disease severity and comorbid metabolic syndrome (MetS) in patients with hidradenitis suppurativa (HS) are lacking. Objective: To identify biomarkers associated with disease severity and comorbid MetS in patients with HS. Methods: Data on hospital outpatients with HS were obtained through clinical examination and interviews. Indicators of systemic inflammation; C-reactive protein (CRP), erythrocyte sedimentation-rate (ESR), neutrophil/lymphocyte-ratio (NLR), platelet/lymphocyte-ratio (PLR), monocyte/lymphocyte-ratio (MLR), platelet/neutrophil-ratio (PNR), pan-immune-inflammation-value (PIV), and systemic-immune-inflammatory-index (SII), were calculated from blood samples. Results: Seven hundred patients were included; of those 444 (63.4%) and 256 (36.6%) were female and male, respectively, with a median age of 38.3 years (IQR = 27.9-51.0). Increasing CRP, ESR, NLR, PIV, and SII (P < .001) were significantly associated with increasing Hurley-stage and international hidradenitis suppurativa severity score system 4 (IHS4)-score in adjusted analysis. A doubling in CRP (OR 1.59 (1.36-1.85), P < .001), ESR (OR 1.39 (1.17-1.66), P < .001) and PIV (OR 1.41 (1.12-1.77) P = .002) was associated with MetS in adjusted analysis. ESR was the best estimator for severe IHS4-score (AUC = 0.72 (0.66-0.77), P < .001) and Hurley III (AUC = 0.79 (0.73-0.85), P < .001) whereas CRP was best for MetS (AUC = 0.67 (0.62-0.72), P < .001). Limitations: Patients in a hospital setting tend to have more severe disease. Conclusion: Biomarkers like CRP, ESR, and PIV measuring systemic inflammation were associated with disease severity and comorbid MetS in patients with HS.

Evaluating the inhibition of IL-17A and TNFα in a cartilage explant model cultured with Th17-derived cytokines.

Introduction: T-helper 17 (Th17) cells produce IL-17A playing a critical role in activating the pathogenic chain leading to joint tissue inflammation and destruction. Elevated levels of Th17 cells and IL-17A have been detected in skin lesions, blood, and synovial fluid from patients with psoriatic arthritis (PsA) and ankylosing spondylitis (AS). Moreover, IL-17A inhibitors suppress disease activity in psoriasis, PsA and AS, supporting the evidence of IL-17A contributing to the disease pathogenesis. Although, IL-17A inhibitors are widely approved, it remains unclear how the inhibitory effect of IL-17A alters the extracellular matrix (ECM) of the joint in a Th17-conditioned inflammatory milieu. Therefore, the aim of this study was to establish a cartilage model cultured with conditioned medium from Th17 cells and inhibitors to explore the effect of IL-17A inhibition on joint tissue remodeling. Methods: Naïve CD4+ T cells from healthy human buffy coat were differentiated into Th17 cells, followed by Th17 cell activation to secrete Th17-related cytokines and molecules into media. The activated Th17 cells were isolated from the conditioned media (CM) and analyzed using flow cytometry to verify Th17 cell differentiation. The CM were assessed with ELISA to quantify the concentrations of cytokines secreted into the media by the Th17 cells. Healthy bovine cartilage explants were cultured with the Th17-CM and treated with IL-17A and TNFα inhibitors for 21 days. In harvested supernatant from the cartilage cultures, MMP- and ADAMTS-mediated biomarker fragments of type II collagen, aggrecan, and fibronectin were measured by ELISA to investigate the ECM remodeling within the cartilage tissue. Results: Th17-CM stimulated a catabolic response in the cartilage. Markers of type II collagen and aggrecan degradation were upregulated, while anabolic marker of type II collagen formation remained on similar levels as the untreated explants. The addition of IL-17A inhibitor to Th17-CM decreased the elevated type II collagen and aggrecan degradation, however, degenerative levels were still elevated compared to untreated group. The addition of TNFα inhibitor completely reduced both type II collagen and aggrecan degradation compared to untreated explants. Moreover, the TNFα inhibitor treatment did not alter the type II collagen formation compared to untreated group. Conclusion: This study suggests that inhibition of IL-17A in Th17-conditioned cartilage tissue only partially reduced the MMP-mediated type II collagen degradation and ADAMTS-mediated aggrecan degradation, while the TNFα inhibitor treatment fully reduced both MMP- and ADAMTS-mediated ECM degradation. This exploratory study where ECM biomarkers are combined with Th17-conditioned ex vivo model may hold great potential as output for describing joint disease mechanisms and predicting structural effects of treatment on joint tissue.

Identification of patient endotypes and adalimumab treatment responders in axial spondyloarthritis using blood-derived extracellular matrix biomarkers.

OBJECTIVE: To explore the potential of a panel of ECM remodelling markers as endotyping tools for axial spondyloarthritis (axSpA) by separating patients into subtypes and investigate how they differ among each other in disease activity scores and response to treatment with adalimumab. METHODS: In three axSpA studies, a panel of 14 blood-based ECM biomarkers related to formation of collagen (PRO-C2, PRO-C3, PRO-C6), degradation of collagen by metalloproteinases (C1M, C2M, T2CM, C3M, C4M, C6M, C10C), matrix metalloproteinase (MMP)-degraded prolargin (PROM), MMP-degraded and citrullinated vimentin (VICM), basement membrane turnover (PRO-C4) and neutrophil activity (CPa9-HNE) were assessed to enable patient clustering (endotyping). MASH (n=41) was a cross-sectional study, while Adalimumab in Axial Spondyloarthritis study (ASIM,n=45) and Danish Multicenter Study of Adalimumab in Spondyloarthritis (DANISH, n=49) were randomised, double-blind placebo-controlled trials of adalimumab versus placebo every other week for 6 or 12 weeks, respectively, followed by active treatment. Biomarker data were log-transformed, standardised by mean centering and scaled by the SD prior to principal component analysis and K-means clustering. RESULTS: Based on all three studies, we identified two orthogonal dimensions reflecting: (1) inflammation and neutrophil activity (driven by C1M and CPa9-HNE) and (2) collagen turnover (driven by PRO-C2). Three endotypes were identified: high inflammation endotype (Endotype1), low inflammation endotype (Endotype 2) and high collagen turnover endotype (Endotype3). Endotype1 showed higher disease activity (Ankylosing Spondylitis Disease Activity Score (ASDAS)) at baseline compared with Endotype2 and Endotype3 and higher percentage of patients responding to adalimumab based on ASDAS clinical improvement at week 24. Endotype3 showed higher percentage of patients with 50% improvement in Bath Ankylosing Spondylitis Disease Activity Index response at week 24 compared with Endotype2. CONCLUSION: These endotypes differ in their tissue remodelling profile and may in the future have utility for patient stratification and treatment tailoring.

Marker for kidney fibrosis is associated with inflammation and deterioration of kidney function in people with type 2 diabetes and microalbuminuria.

BACKGROUND: Diabetic kidney disease is a major cause of morbidity and mortality. Dysregulated turnover of collagen type III is associated with development of kidney fibrosis. We investigated whether a degradation product of collagen type III (C3M) was a risk marker for progression of chronic kidney disease (CKD), occurrence of cardiovascular disease (CVD), and mortality during follow up in people with type 2 diabetes (T2D) and microalbuminuria. Moreover, we investigated whether C3M was correlated with markers of inflammation and endothelial dysfunction at baseline. METHODS: C3M was measured in serum (sC3M) and urine (uC3M) in 200 participants with T2D and microalbuminuria included in an observational, prospective study at Steno Diabetes Center Copenhagen in Denmark from 2007-2008. Baseline measurements included 12 markers of inflammation and endothelial dysfunction. The endpoints were CVD, mortality, and CKD progression (>30% decline in eGFR). RESULTS: Mean (SD) age was 59 (9) years, eGFR 90 (17) ml/min/1.73m2 and median (IQR) urine albumin excretion rate 102 (39-229) mg/24-h. At baseline all markers for inflammation were positively correlated with sC3M (p≤0.034). Some, but not all, markers for endothelial dysfunction were correlated with C3M. Median follow-up ranged from 4.9 to 6.3 years. Higher sC3M was associated with CKD progression (with mortality as competing risk) with a hazard ratio (per doubling) of 2.98 (95% CI: 1.41-6.26; p = 0.004) adjusted for traditional risk factors. uC3M was not associated with CKD progression. Neither sC3M or uC3M were associated with risk of CVD or mortality. CONCLUSIONS: Higher sC3M was a risk factor for chronic kidney disease progression and was correlated with markers of inflammation.

Novel Biomarker of Collagen Degradation Can Identify Patients Affected With Both Axial Spondyloarthritis and Crohn Disease.

OBJECTIVE: Chronic inflammatory arthritis is a hallmark of axial spondyloarthritis (axSpA), where coexistence of Crohn disease (CD) is prominent. We investigated the association between biomarkers of collagen degradation in healthy controls (HCs) and in patients with axSpA, CD, and CD and axSpA overlap (CD-axSpA), with the aim to investigate the ability of the biomarkers to identify patients with CD-axSpA. METHODS: Patients with axSpA who fulfilled Assessment of Spondyloarthritis international Society criteria (n = 13), had biopsy-proven CD (n = 14), had CD-axSpA (n = 10), and HCs (n = 11) undergoing standard-of-care colonoscopies were included in the study. The collagen biomarkers measuring type III, IV, VI and X collagen (C3M, C4M, C6M, and C10C, respectively) were measured in plasma samples from all subject groups. Statistical analysis was performed using an ANCOVA adjusted for age, an area under the receiver-operating characteristic (AUROC) curve analysis, and Spearman correlation. RESULTS: C4M was significantly higher in patients with CD-axSpA overlap compared to axSpA, CD, and HCs (all P < 0.001). In an AUROC analysis, C4M showed a complete separation between the patients with CD-axSpA overlap compared to HC, axSpA and CD with an area under the curve (AUC) = 1.00 (P < 0.001). No differences were found between the patient groups for C3M, C6M, and C10C. No correlations were found between the collagen biomarkers and C-reactive protein, Bath Ankylosing Spondylitis Disease Activity Index, Simple Clinical Colitis Activity Index, or Harvey-Bradshaw Index scores. CONCLUSION: Degradation of type IV collagen quantified by C4M showed a complete separation of patients with CD-axSpA overlap, compared to axSpA, CD, and HCs, and indicates excessive collagen degradation and epithelial turnover. This biomarker could potentially be used to identify patients affected by both manifestations and to guide treatment decisions.

Increased proteolytic cleavage of osteoglycin is associated with a stable plaque phenotype and lower risk of cardiovascular events.

BACKGROUND AND AIMS: Extracellular matrix (ECM) remodeling is one of the key components in the formation of vulnerable atherosclerotic plaques and cardiovascular events. We recently showed that the full-length ECM-proteoglycan osteoglycin was associated with plaque vulnerability and future cardiovascular events. In the present study, we aimed to investigate the association of cleaved osteoglycin with plaque phenotype. METHODS: Two-hundred human carotid plaques were analyzed by immunohistochemistry. Cleaved osteoglycin and active caspase-3 were assessed by ELISA. ECM components (collagen, elastin and glycosaminoglycans) were assessed by colorimetric assays in plaque tissue homogenates. Matrix metalloproteinases (MMPs) were assessed using Milliplex. MMP-cleavage of osteoglycin and its effect on apoptosis were studied in vitro. Cardiovascular events were recorded during follow-up using national registries. RESULTS: Plaque levels of cleaved osteoglycin were significantly higher in asymptomatic plaques and correlated to α-actin plaque area, collagen, elastin and inversely to lipids, active. caspase-3 and a histological vulnerability index. Cleaved osteoglycin correlated to several MMPs, especially MMP-12, which was also shown to cleave osteoglycin in vitro. In vitro cleavage of osteoglycin was also associated with less smooth muscle cell apoptosis. Patients with high plaque levels of cleaved osteoglycin had a significantly lower risk to suffer from future cardiovascular events. CONCLUSIONS: The current study shows that cleaved osteoglycin is associated with a stable plaque phenotype and lower risk for future cardiovascular events. Potentially due to reduced cell apoptosis and ability to retain LDL. These results indicate that targeting the cleavage of osteoglycin may be a potential therapeutic strategy to stabilize plaques.

Baseline serum levels of cross-linked carboxy-terminal telopeptide of type I collagen predict abatacept treatment response in methotrexate-naive, anticitrullinated protein antibody-positive patients with early rheumatoid arthritis.

OBJECTIVE: To investigate correlations between biomarkers of bone remodelling and extracellular matrix turnover with baseline disease activity and treatment response in patients with early rheumatoid arthritis (RA). METHODS: Assessing Very Early Rheumatoid arthritis Treatment-2 (AVERT-2; NCT02504268) included disease-modifying antirheumatic drug-naive, anti-citrullinated protein antibody (ACPA)-positive patients randomised to weekly subcutaneous abatacept+methotrexate (MTX) or abatacept placebo+MTX for 56 weeks. This post hoc exploratory subanalysis assessed the association between baseline disease activity and eight biomarkers (Spearman's correlation coefficient), and whether baseline biomarkers (continuous or categorical variables) could predict treatment response at weeks 24 and 52 (logistic regression). RESULTS: Patient characteristics were similar between overall (n=752) and biomarker subgroup (n=535) populations and across treatments. At baseline, neoepitopes of matrix metalloproteinase-mediated degradation products of types III and IV collagen and of C reactive protein (CRP) showed the greatest correlations with disease activity; cross-linked carboxy-terminal telopeptide of type I collagen (CTX-I) showed weak correlation. Only CTX-I predicted treatment response; baseline CTX-I levels were significantly associated with achieving Simplified Disease Activity Index remission and Disease Activity Score in 28 joints (DAS28 (CRP)) <2.6 (weeks 24 and 52), and American College of Rheumatology 70 response (week 52), in patients treated with abatacept+MTX but not abatacept placebo+MTX. CTX-I predicted significant differential response between arms for DAS28 (CRP) <2.6 (week 24). Treatment differences were greater for abatacept+MTX in patients with medium/high versus low baseline CTX-I. CONCLUSION: In MTX-naive, ACPA-positive patients with early RA, baseline CTX-I predicted treatment response to abatacept+MTX but not abatacept placebo+MTX.

Extracellular matrix protein turnover markers are associated with axial spondyloarthritis-a comparison with postpartum women and other non-axial spondyloarthritis controls with or without back pain.

BACKGROUND: Axial spondyloarthritis (axSpA) is a common chronic inflammatory disease, associated with extracellular matrix (ECM) remodeling of the cartilage, bone, and connective tissues. The primary symptom of axSpA is back pain, caused by inflammation. However, there is a medical need to truly identify patients with axSpA from other subjects with buttock or low back pain attributable to other reasons. We aimed to investigate circulating biomarkers of ECM/inflammation (MMP-degraded type I (C1M), II (C2M, T2CM), III (C3M), IV (C4M), VI (C6M), and X (C10C, COL10NC) collagens, CRPM, PROM and VICM) and ECM formation of type II (PRO-C2), III (PRO-C3), IV (PRO-C4), and VI (PRO-C6) collagens as potential biomarkers to identify patients with axSpA. METHODS: We measured biomarkers from a cross-sectional study with 204 participants by enzyme-linked immunosorbent assay (ELISA). The study included axSpA patients (N = 41), women with postpartum buttock/pelvic pain (N = 46), disc herniation (N = 25), and a group of healthy subjects (including women without postpartum pelvic pain (N = 14), subjects with various types of physical strain (cleaning staff (N = 26) long-distance runners (N = 23)), and healthy men (N = 29)). Differences between the groups were calculated by ANCOVA and AUC, while Spearman's correlations were performed with ECM biomarkers and clinical scores. RESULTS: Patients with axSpA expressed significantly higher levels of C1M, C4M, and VICM (p < 0.05-p < 0.0001) compared to all the non-axSpA control groups. Further, C6M and PRO-C4 were significantly higher in patients with axSpA (both p < 0.0001) compared to women with postpartum pelvic pain and healthy subjects, whereas PRO-C3 was significantly lower compared to healthy subjects (p = 0.01). The best ECM common biomarker to differentiate between axSpA and the non-axSpA control groups was PRO-C4 (AUC ≥ 0.75; specificity ≥ 0.79, sensitivity = 0.65). Mild correlations were observed between collagen turnover and inflammation biomarkers and CRP and MRI (ρ ≥ 0.3; p < 0.05-p < 0.001). CONCLUSIONS: Biomarkers of type I, IV, and VI collagen and biomarkers of inflammation showed an altered turnover in patients with axSpA compared with the non-axSpA control groups. Such biomarkers may be useful in combination with MRI or independently to separate patients with axSpA from other back pain conditions.

Collagen Turnover Biomarkers Associate with Active Psoriatic Arthritis and Decrease with Guselkumab Treatment in a Phase 3 Clinical Trial (DISCOVER-2).

INTRODUCTION: Guselkumab, a novel interleukin-23p19 subunit monoclonal antibody, has been shown to effectively improve the diverse manifestations of active psoriatic arthritis (PsA) in two phase 3 trials (DISCOVER-1, DISCOVER-2). Serum concentrations of extracellular matrix (ECM) biomarkers at baseline and following treatment with guselkumab were evaluated in patients with active PsA, and the relationship of these biomarkers with baseline PsA characteristics and clinical response to guselkumab treatment was explored. METHODS: Serum samples were collected at weeks 0, 4, 24, and 52 from a selected subset (N = 260) of the 739 biologic-naïve patients with PsA treated with guselkumab 100 mg every 4 or 8 weeks or placebo in DISCOVER-2. Demographically matched healthy controls (N = 76) were used for comparison. The samples were analyzed for ECM biomarkers associated with collagen degradation (C1M, C2M, C3M, C4M, C6M, C10C) and collagen formation (PRO-C1, PRO-C2, PRO-C3, PRO-C4, PRO-C6). RESULTS: Baseline concentrations of collagen degradation biomarkers C1M, C3M, C4M, and C6M and collagen formation biomarkers PRO-C3 and PRO-C6 were significantly higher (i.e., ≥ 1.25-fold and false discovery rate adjusted p < 0.05) in PsA patients than in healthy controls. Serum C1M, C3M, C4M, and C6M levels declined from baseline in guselkumab-treated patients in both dosing regimens. In addition, guselkumab-treated ACR20 responders (≥ 20% improvement in American College of Rhematology response criteria) had significantly lower C1M levels than ACR20 nonresponders. CONCLUSION: These data demonstrate that serum collagen biomarkers are elevated in patients with PsA compared with healthy controls and that treatment with guselkumab decreases levels of C1M, C3M, C4M, and C6M. Importantly, C1M serves as a biomarker that associates with improvement of joint signs and symptoms. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03158285.

Proteoglycan Remodeling Is Accelerated in Females with Angina Pectoris and Diffuse Myocardial Fibrosis: the iPOWER Study.

Angina and no obstructive coronary artery disease (CAD) have an unfavorable prognosis, possibly due to diffuse myocardial fibrosis (DMF). In DMF the proteoglycans biglycan and versican are actively remodeled by matrix metalloproteinase. We investigated biglycan and versican in females with angina and possible DMF assessed by cardiac magnetic resonance (CMR). Seventy-one females with angina and no obstructive CAD were included. Asymptomatic females served as controls. Versican and biglycan were measured and CMR was performed measuring extracellular volume. Biglycan and versican levels were higher in symptomatic females compared with controls; 31.4 ng/mL vs. 16.4 ng/mL (p < 0.001) and 2.1 ng/mL vs. 1.8 ng/mL (p < 0.001) and moderately correlated to extracellular volume (r2 = 0.38, p<0.001 and r2 = 0.26, p = 0.015). Turnover of biglycan and versican was increased in angina females compared with controls and associated with extracellular volume, supporting a link between angina with no obstructive CAD and fibrotic remodeling.

Exploring IL-17 in spondyloarthritis for development of novel treatments and biomarkers.

Spondyloarthritis (SpA) is an umbrella term describing a family of chronic inflammatory rheumatic diseases. These diseases are characterised by inflammation of the axial skeleton, peripheral joints, and entheseal insertion sites throughout the body which can lead to structural joint damage including formation of axial syndesmophytes and peripheral osteophytes. Genetic evidence, preclinical and clinical studies indicate a clear role of interleukin (IL)- 23 and IL-17 as mediators in SpA pathogenesis. Targeting the IL-23/-17 pathways seems an efficient strategy for treatment of SpA patients, and despite the remaining challenges the pathway holds great promise for further advances and improved therapeutic opportunities. Much research is focusing on serological markers and imaging strategies to correctly diagnose patients in the early stages of SpA. Biomarkers may facilitate personalised medicine tailored to each patient's specific disease to optimise treatment efficacy and to monitor therapeutic response. This narrative review focuses on the IL-17 pathway in SpA-related diseases with emphasis on its role in pathogenesis, current approved IL-17 inhibitors, and the need for biomarkers reflecting core disease pathways for early diagnosis and measurement of disease activity, prognosis, and response to therapy.

A serological type II collagen neoepitope biomarker reflects cartilage breakdown in patients with osteoarthritis.

Objectives: There is an unmet medical need for biomarkers in OA which can be applied in clinical drug development trials. The present study describes the development of a specific and robust assay measuring type II collagen degradation (T2CM) and discusses its potential as a noninvasive translational biomarker. Methods: A type II collagen specific neoepitope (T2CM) was identified by mass spectrometry and monoclonal antibodies were raised towards the epitope, employed in a chemiluminescence immunoassay. T2CM was assessed in bovine cartilage explants with or without MMP-13 inhibitor, and explant supernatants were analyzed by Western blot. T2CM was measured in plasma samples from one study (n â€‹= â€‹48 patients) where OA patients were referred to total knee replacement (TKR). Additionally, T2CM was quantified in serum from OA patients receiving salmon calcitonin treatment (sCT) (n â€‹= â€‹50) compared to placebo (n â€‹= â€‹57). Results: The T2CM assay was technically robust (13/4 â€‹% inter/intra-variation) and specific for the type II collagen fragment cleaved by MMP-1 and -13. The MMP-13 inhibitor reduced the T2CM release from bovine cartilage explants receiving catabolic treatment. These results were confirmed by Western blot. In human end-stage OA patients (scheduled for TKR), the T2CM levels were elevated compared to moderate OA (p<0.004). The OA patients receiving sCT had lower levels of T2CM compared to placebo group after 1, 6, and 24 months of treatment (p â€‹= â€‹0.0285, p â€‹= â€‹0.0484, p â€‹= â€‹0.0035). Conclusions: To our knowledge, T2CM is the first technically robust serological biomarker assay which has shown biological relevance in ex vivo models and OA cohorts. This suggests that T2CM may have potential as a translational biomarker for cartilage degradation.

Biomarkers of extracellular matrix formation are associated with acute-on-chronic liver failure.

BACKGROUND & AIMS: Acute-on-chronic liver failure (ACLF) is characterised by organ failure(s), high short-term mortality, and, pathophysiologically, deranged inflammatory responses. The extracellular matrix (ECM) is critically involved in regulating the inflammatory response. This study aimed to determine alterations in biomarkers of ECM turnover in ACLF and their association with inflammation, organ failures, and mortality. METHODS: We studied 283 patients with cirrhosis admitted for acute decompensation (AD) with or without ACLF, 64 patients with stable cirrhosis, and 30 healthy controls. A validation cohort (25 ACLF, 9 healthy controls) was included. Plasma PRO-C3, PRO-C4, PRO-C5, PRO-C6, and PRO-C8 (i.e. collagen type III-VI and VIII formation) and C4M and C6M (i.e. collagen type IV and VI degradation) were measured. Immunohistochemistry of PRO-C6 was performed on liver biopsies (AD [n = 7], ACLF [n = 5]). A competing-risk regression analysis was performed to explore the prognostic value of biomarkers of ECM turnover with 28- and 90-day mortality. RESULTS: PRO-C3 and PRO-C6 were increased in ACLF compared to AD (p = 0.089 and p <0.001, respectively), whereas collagen degradation markers C4M and C6M were similar. Both PRO-C3 and PRO-C6 were strongly associated with liver function and inflammatory markers. Only PRO-C6 was associated with extrahepatic organ failures and 28- and 90-day mortality (hazard ratio [HR; on log-scale] 6.168, 95% CI 2.366-16.080, p <0.001, and 3.495, 95% CI 1.509-8.093, p = 0.003, respectively). These findings were consistent in the validation cohort. High PRO-C6 expression was observed in liver biopsies of patients with ACLF. CONCLUSIONS: This study shows, for the first time, evidence of severe net interstitial collagen deposition in ACLF and makes the novel observation of the association between PRO-C6 and (extrahepatic) organ failures and mortality. Further studies are needed to define the pathogenic significance of these observations. LAY SUMMARY: This study describes a disrupted turnover of collagen type III and VI in Acute-on-chronic liver failure (ACLF). Plasma biomarkers of these collagens (PRO-C3 and PRO-C6) are associated with the severity of liver dysfunction and inflammation. PRO-C6, also known as the hormone endotrophin, has also been found to be associated with multi-organ failure and prognosis in acute decompensation and ACLF.