Reflections from the OARSI 2022 clinical trials symposium: The pain of OA-Deconstruction of pain and patient-reported outcome measures for the benefit of patients and clinical trial design

OBJECTIVE

Osteoarthritis (OA) drug development is hampered by a number of challenges. One of the main challenges is the apparent discordance between pain and structure, which has had a significant impact on drug development programs and has led to hesitance among stakeholders. Since 2017, the Clinical Trials Symposium (CTS) has been hosted under the Osteoarthritis Research Society International (OARSI) leadership. OARSI and the CTS steering committee yearly invite and encourage discussions on selected special subject matter between regulators, drug developers, clinicians, clinical researchers, biomarker specialists, and basic scientists to progress drug development in the OA field.

METHOD

The main topic for the 2022 OARSI CTS was to elucidate the many facets of pain in OA and to enable a discussion between regulators (Food and Drug Administration (FDA) and the European Medicines Agency (EMA)) and drug developers to clarify outcomes and study designs for OA drug development.

RESULTS

Signs or symptoms indicative of nociceptive pain occur in 50-70% of OA patients, neuropathic-like pain in 15-30% of patients, and nociplastic pain in 15-50% of patients. Weight-bearing knee pain is associated with bone marrow lesions and effusions. There are currently no simple objective functional tests whose improvements correlate with patient perceptions.

CONCLUSIONS

The CTS participants, in collaboration with the FDA and EMA, raised several suggestions that they consider key to future clinical trials in OA including the need for more precise differentiation of pain symptoms and mechanisms, and methods to reduce placebo responses in OA trials.

OP0031 SEROLOGICAL COLLAGEN BIOMARKERS CAN DIFFERENTIATE PATIENTS WITH PSORIASIS FROM PSORIATIC ARTHRITIS

Background

Psoriasis is a common chronic immune-mediated skin disease. About 25% of psoriasis patients have psoriatic arthritis (PsA) which is a chronic inflammatory disease affecting the joints, enthesis, and axial skeleton. Delayed diagnosis of PsA is associated with joint damage and disability. Therefore, optimized screening methods including identifying predictors of arthritis in patients with psoriasis have become a medical priority. Collagens are major proteins in all tissues, including skin, bone, cartilage, and connective tissues, which are affected by inflammatory processes present in both psoriasis and PsA. Throughout degradation and remodelling of the extracellular matrix (ECM), proteases cleave collagens leading to protein breakdown products which are released into the circulation. These collagen fragments can be quantified in serum as biomarkers of tissue remodelling and may be helpful in screening patients with psoriasis that have or will develop PsA.

Objectives

Our aim is to identify serum biomarkers that can differentiate patients with psoriasis without PsA (PsC) from PsA

Methods

Patients with PsC (n=87, mean ±SD age 42.01 ±12.20, 44% female; underwent a full rheumatologic assessment to exclude PsA) and patients with PsA (n=99, mean ±SD age 45.94 ±12.47, 49% female) were recruited at the Toronto Western Hospital, Canada, after appropriate ethics approval. ECM remodelling was estimated using as indices serological anabolic biomarkers quantifying formation of type III, IV, and VI collagen (PRO-C3, PRO-C4, and PRO-C6 respectively), and catabolic biomarkers measuring degradation of type I, III, IV and VI collagen (C1M, C3M, C4M, C6M respectively). Data are presented as mean ± standard deviation (SD). Statistically significant difference between the two groups was calculated by Mann-Whitney U test and a p-value below 0.05 was considered significant. Area under the receiver operating characteristic (ROC) curve (AUC) analysis was performed to describe the discrimination accuracy of each biomarker between the two patient groups.

Results

Patients with PsA presented higher levels of C1M, C3M, C6M, and PRO-C6 compared to PsC (p<0.0460-p<0.0009, Figure 1 A, B, D, G), while biomarkers levels of C4M, PRO-C3, and PRO-C4 were not significantly different between PsC and PsA patients (Figure 1 C, E, F). Moreover, C1M and C6M were able to separate between PsC and PsA patients with an AUROC=0.6277 (p=0.0027) and AUROC=0.6446 (p=0.0010), respectively, indicating that these biomarkers may be markers of joint involvement (Figure 1 H, I).

Conclusion

This work provides evidence that serum degradation biomarkers of type I and VI collagen were able to differentiate patients with PsA from PsC and may be potential biomarkers of inflammatory systemic musculoskeletal involvement. These findings suggest that serological biomarkers may be used to identify the 25% of psoriasis patients that have PsA.

Disclosure of Interests

Solveig Skovlund Groen: None declared, Signe Holm Nielsen Employee of: Signe Holm Nielsen is employed by Nordic Bioscience, Anne-Christine Bay-Jensen Shareholder of: Anne C. Bay-Jensen holds stock in Nordic Bioscience, Employee of: Anne C. Bay-Jensen is employed by Nordic Bioscience, Mozhgan Rasti: None declared, Darshini Ganatra: None declared, Katerina Oikonomopoulou: None declared, Vinod Chandran: None declared.

POS0006 IDENTIFICATION OF FIBROTIC AND FIBROLYTIC ENDOTYPES IN RHEUMATIC DISEASE COHORTS

Background

Ankylosing spondylitis (AS), psoriatic arthritis (PsA) and systemic lupus erythematosus (SLE) are distinct diseases with common molecular features, such as an imbalance in fibrolysis and fibrosis of connective and calcified tissues. Type III, IV and VI collagens are abundant in connective tissue, and type I, II and X of the skeletal tissue. Blood biomarkers are available to measure fibrolysis (C1M, C2M, C3M, C4M, C6M, C10C) and fibrosis (PRO-C1, PRO-C2, PRO-C3, PRO-C4, PRO-C6) of these collagens.

Objectives

To profile AS, PsA and SLE patients (pts) using blood biomarkers of collagen formation and degradation.

Methods

Baseline serum samples from consenting pts of the AS (NCT02437162/NCT02438787), PsA (NCT0315828), and SLE (NCT02349061) studies were included in the analyses. Healthy donor samples were acquired from Discovery LS. Biomarkers were measured by immunoassays. Biomarker levels were compared by Kruskal-Wallis test. Before hierarchical clustering (Ward.D2), biomarker levels were log-transformed and standardized by median centering and scaling by median absolute deviation (MAD).

Results

When compared with healthy individuals, VICM was elevated in all indications (although markedly less so in SLE pts). The fibrosis marker PRO-C3 was elevated in all indications vs. healthy, while PRO-C4 and PRO-C6 were elevated only in AS and PsA. The fibrolysis markers C3M, C4M and C6M were elevated in all indications. The cartilage fibrosis marker PRO-C2, but not C2M, was elevated in AS and PsA, but not in SLE, ps. The bone fibrosis marker PRO-C1 was at the level of healthy for all. The fibrolysis marker C1M was elevated in all, while elevated C10C was seen only in PsA and SLE, pts (Table 1). Four clusters (C) of blood markers were extracted (Figure 1). C1 was characterized by low biomarker levels (68% of healthy, 1% of PsA, 3% of SLE pts). C2 was described by high levels of C10C and median levels of VICM (20% of healthy, 12% of AS, 19% of PsA, 42% of SLE pts). C3 was described by median biomarker levels (8% of healthy, 67% of AS, 48% of PsA, 46% of SLE pts). C4 had high biomarker levels (4% of healthy, 21% of AS, 31% of PsA, 9% of SLE pts).

Conclusion

Fibrosis and fibrolysis blood biomarkers were significantly elevated in AS, PsA and SLE pts. Subsets of pts from each indication were found in clusters with either low (C1/2), median (C3) or high (C4) levels of fibrosis/fibrolysis biomarkers. These findings may provide a first step towards precision medicine for guiding the use of anti-inflammatory vs. anti-fibrotic treatments in pts with rheumatological disorders.

Disclosure of Interests

Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Nordic Bioscience A/S, Signe Holm Nielsen Shareholder of: Nordic Bioscience A/S, Employee of: Nordic Bioscience A/S, Peder Frederiksen Employee of: Nordic Bioscience A/S, Morten Karsdal Shareholder of: Nordic Bioscience A/S, Employee of: Nordic Bioscience A/S, Warner Chen Employee of: Janssen Research & Development, Sheng Gao Employee of: Janssen Research & Development

OP0224 DISCOVERY PROTEOMICS ANALYSIS IN THE IMI-APPROACH COHORT SHOWS THE DIFFERENTIAL MODULATION AT 24 MONTHS OF PROTEIN PROFILES ASSOCIATED WITH STRUCTURAL OR PAIN PROGRESSION IN OSTEOARTHRITIS

Background

The characterization of differential molecular endotypes in osteoarthritis (OA) is essential for enabling patient stratification to enhance clinical trials, facilitate the development of targeted and individualized treatments.

Objectives

This study aimed to characterize the profile and dynamics over 24 months (24M) of proteins present in the sera from patients in the IMI-Applied Public-Private Research enabling OsteoArthritis Clinical Headway (APPROACH) cohort who exhibited structural (radiographic) and pain progression compared to participants who did not progressed during this period.

Methods

Forty-five patients enrolled in the IMI-APPROACH cohort were selected for the proteomic analysis. Among these, 15 showed the highest structural progression (group S) and 15 the highest pain progression (group P) at 24M, according to the APPROACH criteria [1], while 15 did not progressed neither in S nor in P. Baseline (BL) and 24M serum samples were depleted of the top 14 most abundant proteins and then analysed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) on a nanoElute-LC coupled to a high-resolution TIMS-QTOF (timsTOF Pro, Bruker Daltonics). Proteins were identified and quantified using the LFQ algorithm of MaxQuant software. Further statistical and bioinformatic analyses were performed using Perseus and OmicsAnalyst software.

Results

The proteomic analysis resulted in the identification of 558 proteins (10,466 peptides) in the serum samples. A label-free quantification algorithm was employed to quantify 468 proteins in the samples. Hierarchical clustering of the data showed the differences in protein abundance were more relevant longitudinally (BL to 24M) than in cross-sectional comparisons between the three groups under study (N, P or S). Sixty-three proteins were significantly altered (fold change >=1.5, p<0.05) when comparing BL to 24M in the N group (15 increased and 48 decreased), 53 in the P group (20 increased and 33 decreased) and 93 in the S group (19 increased and 74 decreased). Interestingly, two different endotypes were detected at baseline in the N and S groups, based on these protein modulations.

The overlapping of these proteomic profiles was analyzed between groups and is shown in the Figure 1. Proteins modulated specifically in the N group may be associated with mechanisms related with joint repair. On the other hand, six proteins (including two apolipoproteins) were increased at 24M only in the P group. Finally, 30 proteins were modulated only in the S group: five of them increased and 25 decreased. Remarkably, this latter group includes lubricin, chaperones and proteins related with proteoglycan binding, such as COMP, fibronectin or histidine-rich glycoprotein.

Figure 1.

Circulating proteins identified as modulated after 24M follow-up in 45 patients from the APPROACH cohort that progressed in structure (S group; n=15), pain (P group; n=15) or did not progressed (N group; n=15). The numbers with arrows indicate those proteins that decrease (arrow pointing down) or increase (arrow pointing up) compared to baseline.

Conclusion

The modulation of specific protein profiles in serum were identified as associated with the progression in structure, pain or non-progression in patients from the APPROACH cohort. Proteomic changes found specifically in the S group may be interesting circulating markers of the structural affectation occurring in the joint.

References

[1]van Helvoort EM, et al., BMJ Open. 2020 Jul 28;10(7):e035101. doi: 10.1136/bmjopen-2019-035101.

Disclosure of Interests

Cristina Ruiz-Romero: None declared, Patrik Önnerfjord: None declared, Valentina Calamia: None declared, Patricia Fernández Puente: None declared, Lucía Lourido: None declared, Rocío Paz González: None declared, Pawel Widera: None declared, Jaume Bacardit: None declared, Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience, Employee of: Nordic Bioscience, Francis Berenbaum Consultant of: AstraZeneca, Boehringer, Bone Therapeutics, CellProthera, Expanscience, Galapagos, Gilead, Grunenthal, GSK, Eli Lilly, Merck Sereno, MSD, Nordic, Nordic Bioscience, Novartis, Pfizer, Roche, Sandoz, Sanofi, Servier, UCB, Peptinov, 4P Pharma, 4Moving Biotech, Grant/research support from: TRB Chemedica, Ida K. Haugen Consultant of: Abbvie and Novartis, Grant/research support from: Pfizer, Margreet Kloppenburg Consultant of: Abbvie, Pfizer, Levicept, GlaxoSmithKline, Merck-Serono, Kiniksa, Flexion, Galapagos, Jansen, CHDR, Novartis, UCB, Simon Mastbergen: None declared, Jonathan Larkin Shareholder of: GlaxoSmithKline, Employee of: GlaxoSmithKline, Ali Mobasheri Consultant of: Merck KGaA, Kolon TissueGene, Pfizer Inc., Galapagos-Servier, Image Analysis Group (IAG), Artialis SA, Aché Laboratórios Farmacêuticos, AbbVie, Guidepoint Global, Alphasights, Science Branding Communications, GSK, Flexion Therapeutics, Pacira Biosciences, Sterifarma, Bioiberica, SANOFI, Genacol, Kolon Life Science, BRASIT/BRASOS, GEOS, MCI Group, Alcimed, Abbot, Laboratoires Expansciences, SPRIM Communications, Frontiers Media and University Health Network (UHN) Toronto, Grant/research support from: Merck KGaA, Kolon TissueGene, Pfizer Inc., Galapagos-Servier, Image Analysis Group (IAG), Artialis SA, Aché Laboratórios Farmacêuticos, AbbVie, Guidepoint Global, Alphasights, Science Branding Communications, GSK, Flexion Therapeutics, Pacira Biosciences, Sterifarma, Bioiberica, SANOFI, Genacol, Kolon Life Science, BRASIT/BRASOS, GEOS, MCI Group, Alcimed, Abbot, Laboratoires Expansciences, SPRIM Communications, Frontiers Media and University Health Network (UHN) Toronto, Francisco J. Blanco Consultant of: Gedeon Richter Plc., Bristol-Myers Squibb International Corporation (BMSIC), Sun Pharma Global FZE, Celgene Corporation, Janssen Cilag International N.V, Janssen Research & Development, Viela Bio, Inc., Astrazeneca AB, UCB BIOSCIENCES GMBH, UCB BIOPHARMA SPRL, AbbVie Deutschland GmbH & Co.KG, Merck KGaA, Amgen, Inc., Novartis Farmacéutica, S.A., Boehringer Ingelheim España, S.A, CSL Behring, LLC, Glaxosmithkline Research & Development Limited, Pfizer Inc, Lilly S.A., Corbus Pharmaceuticals Inc., Biohope Scientific Solutions for Human Health S.L., Centrexion Therapeutics Corp., Sanofi, TEDEC-MEIJI FARMA S.A., Kiniksa Pharmaceuticals, Ltd., Fundación para la Investigación Biomédica Del Hospital Clínico San Carlos, Grünenthal and Galapagos, Grant/research support from: Pfizer

POS0024 PREDICTION OF SPONTANEOUS IMPROVEMENT IN PATIENT REPORTED OUTCOME SCORES IN OSTEOARTHRITIS USING MARKERS OF JOINT TISSUE TURNOVER

Background

Osteoarthritis (OA) is a chronic disease characterized by pain and disability. There is no modifying treatment approved for OA today. This may be attributed to the difficulty generating a robust response based on patient-reported outcomes (PROs) linked to the drug mode of action. There is a need in drug development to test and validate biomarkers that objectively relate to PROs or even predict changes in PROs. Biomarkers of cartilage and bone turnover are associated with structural and symptomatic progression.1 In addition, recent findings suggest that a subset of OA patients have elevated serum levels of C-reactive protein metabolites (CRPM), which is predictive of radiographic progression.2,3

Objectives

This explorative study aimed to investigate the association between PROs and markers of joint tissue formation and degradation in patients with either high or low levels of CRPM. In particular, whether levels could predict spontaneous improvement in PROs.

Methods

146 knee OA patients, 62% women, from the NYU cohort were included.4 Mean (SD) age, 62.5 (10.1); BMI, 26.6 (3.6); 32% NSAID users; and 67.6% w. radiographic OA (KL≥2). PROs were recorded at baseline (BL) and 2 years (FU), and the current investigation was: WOMAC pain, stiffness, and function. The mean (SD) for WOMAC pain, stiffness, and function were 35.4 (22.9), 40.8 (25.7), and 41.7 (28.3) mm on a 100 mm scale. Twenty-one healthy individuals were included as a reference. Eight serum biomarkers of type I, II, III, and IV collagen degradation (C1M, C2M, C3M, C4M) and formation (PRO-C1, PRO-C2, PRO-C3, and PRO-C4) as well as the inflammatory biomarker CRPM, were assessed at baseline. LN-transformed data was adjusted for race, Sec, age, BMI, and NSAID use when comparing OA to controls and in the predictive model. Marked symptomatic (S) OA was defined as ≥40 mm in either of the WOMAC scores at BL and improvement as 20 mm decreased in any of the scores from BL to FU.

Results

There was no difference in mean marker levels between controls and OA patients. Only C2M correlated with the WOMAC scores at baseline in the ALL population (p <0.001). This correlation was maintained in both the high and low CRPM groups. A high correlation was observed between the PROs and PRO-C4, C1M and C3M, but only in the high CRPM group. Next, we investigated whether the markers could predict symptomatic improvement in patients with marked SOA. A combination of C4M, Age and BMI was predictive of pain improvement in the ALL population (Table 1). Interestingly the predictors were different in the low vs. high CRPM group; PRO-C2, PRO-C3, PRO-C4 and Sex predicted a 20 mm decrease in WOMAC pain in the low group, while C2M alone predicted an improvement in the high CRPM group. Moreover, C2M predicted an improvement in stiffness in the CRPM high, but not in the low CRPM group. C1M and C3M predicted a 20 mm decrease in function only in the high CRPM group.

Conclusion

Levels of the joint tissue markers weew subtle compared to controls. However, the markers, together with sex and BMI, could predict symptomatic improvement. This may provide novel insight into the link between tissue turnover and PROs.

References

[1]Kraus, V. B. et al. Predictive validity of biochemical biomarkers in knee osteoarthritis: Data from the FNIH OA Biomarkers Consortium. Ann. Rheum. Dis.76, 186–195 (2017).

[2]Alexander, L. C. et al. A matrix metalloproteinase-generated neoepitope of CRP can identify knee and multi-joint inflammation in osteoarthritis. Arthritis Res. Ther.23, 226 (2021).

[3]Bay-Jensen, A. C. et al. Serum C-reactive protein metabolite (CRPM) is associated with incidence of contralateral knee osteoarthritis. Sci. Rep.11, (2021).

[4]Attur, M. et al. Plasma levels of interleukin-1 receptor antagonist (IL1Ra) predict radiographic progression of symptomatic knee osteoarthritis. Osteoarthr. Cartil.23, 1915–1924 (2015).

Disclosure of Interests

Mukundan Mukundan: None declared, Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Nordic Bioscience A/S, Jonathan Samuels: None declared, Morten Karsdal Shareholder of: Nordic Bioscience A/S, Employee of: Nordic Bioscience A/S, Steven Abramson: None declared

AB0105 A HIGHLY SENSITIVE NEO-EPITOPE BIOMARKER OF TYPE II COLLAGEN C- TERMINAL IS ASSOCIATED WITH CARTILAGE FORMATION

Background

Altered extracellular matrix (ECM) remodeling is a common event in rheumatic diseases. Type II collagen is the most abundant ECM protein in the cartilage and provides tensile elasticity and strength to enable support to the joints. Chondrocalcin, also known as the C-terminal propeptide of type II collagen, is among the most highly synthesized polypeptides in cartilage. It is cleaved off by BMP-1/C-endopeptidase during maturation and plays a role in assembly of type II collagen and in calcification of cartilage matrix. When cleaved off, the chondrocalcin fragments are released into circulation, where they can be quantified in a blood sample.

Objectives

This study aimed at developing an immunoassay targeting a neo-epitope of chondrocalcin, named CALC2. Moreover, we explored its biomarker potential to evaluate type II collagen formation in an ex vivo human osteoarthritis (OA) cartilage explant model (HEX) with anabolic treatment, and in serum from healthy controls, patients with rheumatoid arthritis (RA) and patients with ankylosing spondylitis (AS).

Methods

A novel direct immunoassay targeting the neo-epitope of type II collagen C-terminal (PIICP) was developed and technically validated. The technical validation included inter- and intra-variation, linearity, spiking recovery, stability, and specificity. Specificity of the monoclonal antibody was tested using an elongated peptide, a truncated peptide, and a non-sense peptide to exclude possible cross-reactivity. CALC2 levels were measured in supernatant from HEX cultured for 35 days in serum free DMEM/F12 medium with IGF-1 (Insulin-like Growth Factor-1) (100 ng/mL), including a control group without (w/o) treatment. The supernatant was harvested 3 times weekly and replaced with new culture medium with IGF-1. Biomarker results were confirmed by western blot. Serum samples from 18 healthy donors (mean age 35.8 ± SD 3.8, 100% Caucasian), 19 patients with AS (mean age 35.8 ± SD 3.2, 100 % Caucasian) and 18 patients with RA (mean age 35.8 ± SD 3.4), 100% Caucasian) were also measured by CALC2. Linear regression models with pairwise comparisons were performed.

Results

A technically robust and specific assay was developed. The inter- and intra-assay variation of CALC2 was determined as 12% and 7% respectively. CALC2 showed a good dilution recovery, spiking recovery, and storage /freeze-thaw stability (All, 100%±20%). CALC2 showed specificity towards the targeted sequence and did not show any reactivity towards the truncated peptide, elongated peptide, or non-sense peptide. CAL2 neoepitope levels were significantly elevated after 14, 21 and 28 days of IGF-1 treatment compared to untreated (p<0.01, p<0.0001 p<0.001, respectively). The western blot confirmed the CALC2 results by the presence of a band of ~35 kDa in all explants, corresponding to the weight of chondrocalcin previously stablished (1). Furthermore, the bands were more pronounced at day 21 in the IGF-1 treated explant compared to the untreated explant. CALC2 also showed significantly lower levels in patients with RA compared to controls (p=0.003; mean 0.32 ng/mL ± SD 0.16 vs 0.64 ng/mL ± SD 0.31).

Conclusion

Higher levels of CALC2 were detected in supernatants from explants after 14, 21 and 28 days of IGF-1 treatment compared to untreated. Lower levels of CALC2 were present in patients with RA compared to healthy controls. Overall, this suggests that CALC2 may have potential as biomarker for type II collagen formation. However, further preclinical and clinical studies are required to validate these findings.

References

[1]Poole R, Choi H. Association of an extracellular protein (chondrocalcin) with the calcification of cartilage in endochondral bone formation. J Cell Biol. 1984;98(1):54–65.

Figure 1.

CALC2 measurements in HEX model.

Disclosure of Interests

Helena Port: None declared, Christian Thudium Shareholder of: Shareholder at Nordic Bioscience A/S, Thorbjørn Gantzel: None declared, Anne-Christine Bay-Jensen Shareholder of: Shareholder of Nordic Bioscience A/S, Morten Karsdal Shareholder of: Shareholder at Nordic Bioscience A/S, Signe Holm Nielsen Shareholder of: Shareholder at Nordic Bioscience A/S

POS1097 BIOMARKERS OF INFLAMMATION AND JOINT TISSUE TURNOVER CAN HELP IMPROVING THE DIFFERENTIATION BETWEEN OSTEOARTHRITIS AND PSORIATIC ARTHRITIS PATIENTS

Background

Osteoarthritis (OA) is a slow progressive disease characterized by degeneration within the joint cartilage, leading to destruction and dysfunction of the involved joints. Psoriatic arthritis (PsA) is a chronic inflammatory disease manifesting itself in skin lesions and progressive inflammatory changes within the musculoskeletal system, leading to joint damage and functional limitation. Although OA and PsA are considered to be distinct diseases, they share overlapping clinical and inflammatory features that can cause diagnostic challenges. Throughout these inflammatory and degenerative processes in the joint tissues, proteases hold a major role in remodelling of the extracellular matrix (ECM) which results in protein breakdown products released into the synovial fluid (SF). These protein fragments can be quantified in SF as biomarkers of tissue remodelling and may be helpful in characterizing disease-specific or overlapping pathologies between OA and PsA.

Objectives

Our aim of this study is to measure biomarkers of inflammation and joint tissue turnover in SF to explore the distinct and overlapping pathologies between OA and PsA.

Methods

SF samples were collected from patients with OA (n=54, mean ±SD age 62.1 ±11.9, 48% female) and patients with PsA (n=59, mean ±SD age 47.8±13.3, 37% female) recruited through Toronto Western Hospital, Canada. Study was approved by the local ethics committee. Biomarkers of inflammation reflecting macrophage activity (VICM) and neutrophil activity (CPa9-HNE) were measured in the SF samples. Moreover, ECM remodelling was assessed in the SF samples by biomarkers quantifying type II collagen formation (PRO-C2), fibronectin turnover (FBN-C), and aggrecan degradation (ARGS). Data were log-transformed and presented as mean ± standard deviation (SD). An ANCOVA corrected for age was applied to test the difference between biomarker levels across the two patient groups and a p-value below 0.05 was considered significant. Area under the receiver operating characteristic (ROC) curve (AUC) analysis was performed to describe the discrimination accuracy of each biomarker between the two patient groups.

Results

PsA patients presented significantly higher levels of macrophage; VICM, activity compared to OA (p<0.001, Figure 1A). On the other hand, OA patients demonstrated increased type II collagen formation and aggrecan degradation compared to PsA (p<0.001, Figure 1C, E). Interestingly, no significant difference in biomarkers levels of neutrophil activity and fibronectin remodelling was observed between the two disease groups. Moreover, VICM, PRO-C2, and ARGS showed high distributional difference between OA and PsA patients with an AUROC=0.915 (p<0.001, Figure 1F), AUROC=0.737 (p<0.001, Figure 1G), and AUROC=0.725 (p<0.001, Figure 1H), respectively.

Conclusion

PsA patients demonstrated higher macrophage activity in the SF compared to the OA patients, while higher levels of cartilage formation and degradation were observed in OA patients compared to PsA. No differences between OA and PsA were observed in neutrophil activity and fibronectin turnover, which may mirror the clinical difficulty in telling the two arthritides apart. Identifying the unique characteristics of the pathological processes underlying the two diseases may improve diagnosis and allow for the precise management of both OA and PsA patients.

Disclosure of Interests

Solveig Skovlund Groen: None declared, Signe Holm Nielsen Employee of: Signe is employed by Nordic Bioscience, Anne-Christine Bay-Jensen Shareholder of: Anne C. Bay-Jensen holds stock in Nordic Bioscience, Employee of: Anne C. Bay-Jensen is employed by Nordic Bioscience, Mozhgan Rasti: None declared, Darshini Ganatra: None declared, Katerina Oikonomopoulou: None declared, Vinod Chandran: None declared

OP0095 SINGLE-CELL RNA SEQUENCING REVEALS POTENT ANTI-INFLAMMATORY AND ANTIFIBROTIC ACTIVITIES OF DIMETHYL-ALPHA-KETOGLUTARATE ON EXPLANTED SKIN FROM PATIENTS WITH SYSTEMIC SCLEROSIS

Background

Activated fibroblasts are the main drivers of skin fibrosis in SSc. We have recently identified dimethyl alpha-ketoglutarate (dm-aKG) as a potential repressor of myofibroblast differentiation and profibrotic activity in cultured skin fibroblasts.

Objectives

To further analyse the clinical translation of our findings by investigating the antifibrotic capacity of dm-aKG on explanted skin biopsies from SSc patients.

Methods

We cultured forearm punch skin biopsies from SSc patients (n=10) for 24h ex vivo in the presence/absence of 6 mM dm-aKG. Thereafter, skin biopsies (n=4) were dissociated into single cells using a combined mechanical-enzymatic dissociation protocol, followed by single cell (sc)RNA-seq library preparation (10x Genomics) and sequencing (Illumina, NovaSeq6000, 50,000 reads/cell). We mapped the scRNA-seq reads to the reference genome GRCh38.p13 and analysed the data with R/Bioconductor tools. We deconvoluted cell types in bulk skin transcriptomes from SSc cohorts (GSE: 45485, 59785, 9285, 32413) using human skin scRNA-seq data1. The secretion of IL-6, procollagen-1, PRO-C1 (N-terminal type I collagen pro-peptide), C1M (MMP-degradation fragment of type I collagen), and fibronectin (FBN-C) from cultured skin (n=10) was measured in supernatants by ELISA. We analysed gene and protein expression in TGFβ-activated healthy and SSc dermal fibroblasts (DF, n=10) treated or not with dm-aKG using qPCR, Western blot and ELISA. Contractile properties of DF were assessed by gel contraction assay. Traction forces generated by DF were determined by reference-free traction force microscopy.

Results

Dissociated cultured SSc skin exhibited comparable cell yield and viability in the presence (20,203; 89%) and absence (25,280; 93%) of dm-aKG, respectively. scRNA-seq skin analysis included 20,869 high quality single cell profiles segregating into 10 distinct skin cell populations (Figure 1A). This analysis demonstrated decreased proportion of fibroblasts and increased proportion of keratinocytes in dm-aKG treated skin (p<0.05; Figure 1B). Among skin cell types, skin fibroblasts exhibited the largest amount of differentially expressed genes upon dm-aKG treatment (44%, n=779, x-fold>0.5, FDR<0.05), suggesting that these cells are key targets of dm-aKG therapy in SSc skin. We identified inflammatory/cytokine signalling (hub genes IL6, STAT1) and extracellular matrix (ECM) organization (hub genes MMP1, ITGB3) as top downregulated biological processes in fibroblasts in dm-aKG treated SSc skin (Figure 1C), coinciding with a decreased abundance of proinflammatory skin fibroblast subpopulation. Specifically, these cells were identified as the main source of IL6 (Figure 1D) and were enriched in SSc skin as revealed by deconvolution analysis of skin transcriptomes. Furthermore, dm-aKG reduced the secretion of IL-6, procollagen-1 and C1M, but not pro-C1 and FBN-C, from cultured skin explants. In cultured DF, dm-aKG blocked the inflammatory (IL-6, pSTAT3), profibrotic (aSMA, Fibronectin, Procollagen-1, Pro-C1) and contractile activities, and significantly diminished traction forces exerted by DF on the matrix substrate.

Figure 1.

scRNA-seq – comparison of untreated and dm-aKG treated paired skin biopsies. (A) UMAP plot with annotated skin cells, (B) differential abundance of main skin cell types, (C) volcano plot of DE genes with top downregulated gene ontology (GO) pathways in dm-aKG treated skin fibroblasts, (D) IL6 expression in untreated (blue) and treated (pink) skin fibroblasts.

Conclusion

Dm-aKG broadly interferes with inflammatory and ECM organizational activities of skin fibroblasts in culture and in explanted skin from SSc patients. These results confirm that dm-aKG might represent a potential new therapeutic approach for efficient targeting of skin inflammation and fibrosis in SSc.

References

[1]He H et al. J Allergy Clin Immunol 2020

Acknowledgements

This work was supported by a research grant from FOREUM Foundation for Research in Rheumatology and University Medical Centre Ljubljana.

Disclosure of Interests

Blaž Burja: None declared, Dominique Paul: None declared, Reto Gerber: None declared, Sam G. Edalat: None declared, Muriel Elhai Speakers bureau: BMS, Elena Pachera: None declared, Rahel S. Zingg: None declared, Francesca Michela Pramotton: None declared, Sofie Falkenløve Madsen: None declared, Kristina Buerki: None declared, Giampietro Costanza: None declared, Michael Whitfield: None declared, Anne-Christine Bay-Jensen: None declared, Snežna Sodin-Šemrl: None declared, Matija Tomsic: None declared, Gabriela Kania: None declared, Hubert Rehrauer: None declared, Oliver Distler Speakers bureau: Bayer, Boehringer Ingelheim, Janssen, Medscape, Consultant of: Abbvie, Acceleron, Alcimed, Amgen, AnaMar, Arxx, AstraZeneca, Baecon, Blade, Bayer, Boehringer Ingelheim, Corbus, CSL Behring, 4P Science, Galapagos, Glenmark, Horizon, Inventiva, Kymera, Lupin, Miltenyi Biotec, Mitsubishi Tanabe, MSD, Novartis, Prometheus, Roivant, Sanofi and Topadur, Grant/research support from: Kymera, Mitsubishi Tanabe, Boehringer Ingelheim, Ziga Rotar: None declared, Mark Robinson: None declared, Katja Lakota: None declared, Mojca Frank Bertoncelj: None declared.

AB0131 INDUCTION OF COLLAGEN CHAIN FORMATION IN RESPONSE TO FIBROTIC FACTORS IN DERMAL AND PULMONARY FIBROBLASTS

Background

Systemic sclerosis (SSc) patients who develop pulmonary fibrosis, have an increased mortality rate1. Excessively activated fibroblasts deposit extracellular matrix (ECM), which leads to fibrosis resulting in stiffening of the tissue in both skin and lung. Currently there is no cure for fibrosis in SSc, only drugs which can slow the fibrotic process, and there is therefore, a medical need for further understanding of the pathogenesis. Fibrosis is associated with growth factors, including tumor growth factor beta 1 (TGF-β1) and platelet derived growth factor-ab (PDGF-ab).

Objectives

We investigated how TGF-β1 and PDGF-ab stimulation affected the gene and protein expression of specific collagen chains of type I, III and VI collagens in primary healthy human dermal (DF) and pulmonary fibroblasts (PF).

Methods

The fibroblasts were grown in 0.4% fetal calf serum DMEM, ficoll (to produce a crowded environment) and ascorbic acid for up to 12 days. They were stimulated with TGF-β [0.01 nM], PDGF-ab [3 nM] or a combination of TGF-β [0.01 nM] and PDGF-ab [3 nM], while non-stimulated fibroblasts served as control. ECM protein formation was assessed in supernatant from day 0, 4, 8 and 12, by ELISAs which detects the N-terminal of the pro-collagen of type I and III collagen, and the C5 domain of the α3 chain of type VI collagen. Gene expression was analyzed after 4 days and the relative gene expression was calculated based on multiple reference genes2. Statistical analysis includes one-way and two-way ANOVA.

Results

TGF-β increased the gene expression of Col1α1 in DF (p<0.0001) and Col1α2, Col3α1 and Col6α3 in both DF (p<0.01, p<0.001, p<0.05, respectively) and PF (p<0.0001) compared to control. PDGF-ab showed no difference in gene expression of the DF but decreased multiple genes in PF (p<0.01). The combination of TGF-β and PDGF-ab increased the gene expression of Col1α1 in DF (p<0.01), Col3α1 in PF (p<0.0001) Col1α2 and Col6α3 in both DF (p<0.05 and p<0.01) and PF (p<0.0001) compared to control. None of the stimulations lead to an increase in the Col6α1 and Col6α2. The TGF-β induced gene expression corresponded with increased ECM formation of type I and VI collagen from day 4 (p<0.01), and type III collagen from day 8 (p<0.05) in both DF and PF. PDGF-ab stimulation led to an increased ECM formation of type I and VI collagen in both DF and PF (p<0.01), and type III collagen in DF (p<0.01). The combination stimulation with TGF-β and PDGF-ab induced a corresponding increase in both gene expression and ECM formation of type I and VI collagen in both DF and PF (p<0.01). While the combination increased the ECM formation of type III collagen in both fibroblast types, the gene expression of Col3α1 were only increased in PF (p<0.0001).

Conclusion

This study demonstrates that TGF-β stimulation alone and in combination with PDGF-ab results in increased gene and protein expression of type I and VI collagen in both DF and PF, and additionally type III collagen in PF. However, there was a disconnect between the gene and protein expression profiles after PDGF-ab stimulation, which have to be investigated further. This study may provide new insights to the differences between fibroblast of different origin and their response to fibrotic factors.

References

[1]McNearney, T. A. et al. Pulmonary involvement in systemic sclerosis: Associations with genetic, serologic, sociodemographic, and behavioral factors. Arthritis Care Res.57, 318–326 (2007).

[2]Vandesompele, J. et al. Accurate normalization of real-time quantitative RT-PCR data by geometric averaging of multiple internal control genes. Genome Biol.3, research0034.1 (2002).

Disclosure of Interests

Sofie Falkenløve Madsen: None declared, Pernille Juhl Employee of: Nordic Bioscience, Jannie Marie Bülow Sand Shareholder of: Nordic Bioscience, Employee of: Nordic Bioscience, Morten Karsdal Shareholder of: Nordic Bioscience, Employee of: Nordic Bioscience, Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience, Employee of: Nordic Bioscience, Christian Thudium Shareholder of: Nordic Bioscience, Employee of: Nordic Bioscience

Considerations for understanding protein measurements: Identification of formation, degradation and more pathological relevant epitopes

OBJECTIVES

There is a need for precision medicine and an unspoken promise of an optimal approach for identification of the right patients for value-based medicine based on big data. However, there may be a misconception that measurement of proteins is more valuable than measurement of fewer selected biomarkers. In population-based research, variation may be somewhat eliminated by quantity. However, this fascination of numbers may limit the attention to and understanding of the single. This review highlights that protein measurements (with collagens as examples) may mean different things depending on the targeted epitope - formation or degradation of tissues, and even signaling potential of proteins.

DESIGN AND METHODS

PubMed was searched for collagen, neo-epitope, biomarkers.

RESULTS

Ample examples of assays with specific epitopes, either pathological such as HbA1c, or domain specific such as pro-peptides, which total protein arrays would not have identified were evident.

CONCLUSIONS

We suggest that big data may be considered as the funnel of data points, in which most important parameters will be selected. If the technical precision is low or the biological accuracy is limited, and we include suboptimal quality of biomarkers, disguised as big data, we may not be able to fulfill the promise of helping patients searching for the optimal treatment. Alternatively, if the technical precision of the total protein quantification is high, but we miss the functional domains with the most considerable biological meaning, we miss the most important and valuable information of a given protein. This review highlights that measurements of the same protein in different ways may provide completely different meanings. We need to understand the pathological importance of each epitope quantified to maximize protein measurements.

POS0473 AUTOIMMUNITY AGAINST COLLAGEN IN RHEUMATOID ARTHRITIS (RA): SERUM LEVELS OF IgG AGAINST DENATURED TYPE II COLLAGEN SIGNIFICANTLY ELEVATED IN RA

Background:

The presence of autoantibodies in Rheumatoid Arthritis (RA) is a hallmark of the disease and one of main criteria for diagnosis and clinical classification. Identification of anti-citrullinated protein antibodies (ACPA) and RF-Factors in circulation of RA patients remains the most characteristic and established criteria for diagnosis. However, due to diagnostic limitation of these biomarkers, only approximately 70% of patients with RA can be identified. As a consequence, there is a lack of diagnostic biomarkers for large number of patients. Diagnosis of these patients relies mainly on assessment of their clinical symptoms such as swollen and tender joints. This problem leaves a need for diagnostic improvement and development of more sensitive biomarkers.

Objectives:

In this study, we aimed to develop a sensitive biomarker assay capable to identify and quantify presence of autoantibodies against denatured type II collagen in circulation of patients with RA.

Methods:

The presence and levels of autoantibodies was measured in serum samples from 50 patients with moderate to severe RA who had inadequate response to Methotrexate (average age 51.2, 86% of female, 78% of white race patients). Control cohort involved serum from 42 healthy age matched patients (average age 48.6, 50% of female, 60% of white race patients). Denaturation of the type II collagen was performed by heat treatment for 15 min at 72 °C. Improvement of assay sensitivity was investigated by measurements of autoimmunity levels against denatured and native type II collagen. Assay specificity was assessed by comparison of presence of autoantibodies against type II collagen versus albumin (non-sense control). The normality of data distribution was checked with Shapiro-Wilk test, significance between cohorts with Mann-Whitney nonparametric test and correlations with Spearman’s correlation coefficient (rho).

Results:

Serum levels of autoantibodies against denatured type II collagen were significantly higher in RA patients than in healthy controls (P < 0.0001) (Figure 1). We observed nearly 4-fold difference between both cohorts. Denaturation of type II collagen showed high improvement of assay sensitivity and increased accessibility of collagen for binding of autoantibodies. Developed assay showed specificity for detection of type II collagen autoantibodies by displaying no levels of autoimmunity against other control proteins (albumin). The levels of serum autoantibodies correlated significantly (P < 0.03) with patient disease activity (DAS28) at baseline, displaying rho = 0.3. Our assay showed good technical performance with acceptable inter- and intra- assay variations (18% and 5% respectively).

Figure 1.

Differences in serum levels of autoantibodies against denatured type II collagen between healthy controls and patients with Rheumatoid Arthritis.

Conclusion:

Present findings show that patients with RA carry upregulated levels of circulating autoantibodies directed against type II collagen. Heat-treatment of type II collagen increased exposure of immunogenic epitopes of collagen and enabled for more sensitive detection of autoantibodies directly in patient serum. Developed assay demonstrated potential for specific detection of autoantibodies and may provide additional diagnostic value in RA patients.

Disclosure of Interests:

Patryk Drobinski: None declared, Elijah Aighobahi: None declared, Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Nordic Bioscience A/S, Morten Karsdal Shareholder of: Nordic Bioscience A/S, Employee of: Nordic Bioscience A/S

POS0431 FIBROBLASTS ARE NOT JUST FIBROBLASTS - CLEAR DIFFERENCES IN ECM PRODUCTION BETWEEN DERMAL AND LUNG FIBROBLASTS IN RESPONSE TO GROWTH FACTORS

Background:

Many systemic sclerosis (SSc) patients develop lung fibrosis, which contribute significantly to increased mortality1. Activated and proliferating fibroblasts are responsible for the excessive extracellular matrix (ECM) formation and stiffening of the connective tissue leading to skin and lung fibrosis. There is currently no effective treatment for the fibrosis in SSc and there is therefore a medical need for further understanding the pathogenesis of fibrosis. Fibrosis is associated with different growth factors, including tumor growth factor beta 1 (TGF-β1) and platelet derived growth factor-ab (PDGF-ab)2.

Objectives:

We investigated how stimulation with TGF-β1 and PDGF-ab affected the migration capacity and the ECM production using translational biomarkers of type I, III and VI collagens in healthy human dermal and lung fibroblasts.

Methods:

The fibroblasts were grown in DMEM media containing 0.4% fetal calf serum, ficoll (to produce a crowded environment) and ascorbic acid for up to 12 days. The cells were stimulated with TGF-β1 [0.04-1 nM] or PDGF-ab [3 nM] at treatment initiation and changed twice a week. Non-stimulated fibroblasts (w/o) were used as control. A wound was induced by scratching the cells at day 1 after treatment initiation and the migration was followed for 2 days. Type I, III and VI collagen formation (PRO-C1, PRO-C3 and PRO-C6, respectively) were evaluated by validated ELISAs (Nordic Bioscience) in supernatant from day 0, 4, 8 and 12. Statistical analysis included 2-way ANOVA and Dunnett’s test.

Results:

The PDGF-ab stimulated dermal fibroblasts migrated significantly more than the non-stimulated (p<0.0001) and TGF-β1 stimulated (p<0.001) dermal fibroblasts 48 hours after the scratch (migration app. 70%, 30% and 30% respectively). There was no difference between the migration of the non-stimulated, TGF-β1 and PDGF-ab stimulated lung fibroblasts after 48 hours, as all migrated to approximately 70%.

TGF-β1 stimulation led to a significant increase in type I collagen formation (PRO-C1) in both dermal and lung fibroblasts from day 4 and onwards compared to w/o (p<0.0001). TGF-β1 also lead to a significant increase in type III collagen formation (PRO-C3) from day 8 in lung fibroblasts compared to w/o (p<0.0001). PDGF-ab stimulation led to a significant increase in type III collagen formation in dermal fibroblasts from day 8 compared to w/o (p<0.0001). PDGF-ab stimulation led to a significant increase in type VI collagen formation (PRO-C6) in both dermal and lung fibroblasts from day 4 and onwards compared to w/o (p<0.0001).

Conclusion:

PDGF-ab increased the migration activity of the dermal fibroblasts, where the lung fibroblasts had a general high migration activity. The dermal and lung fibroblasts showcase the same ECM production within both type I and type VI collagen formation. The two fibroblasts types did however react opposite each other regarding the type III collagen formation: the dermal fibroblasts responded to PDGF-ab stimulation, where the lung fibroblasts responded to the TGF-β1 stimulation. The clear differences in the ECM production between the dermal and lung fibroblasts can be important in the search for an effective treatment for fibrosis in SSc and related lung fibrosis.

References:

[1]McNearney, T. A. et al. Pulmonary involvement in systemic sclerosis: Associations with genetic, serologic, sociodemographic, and behavioral factors. Arthritis Care Res.57, 318–326 (2007).

[2]Wynn, T. A. Common and unique mechanisms regulate fibrosis in various fibroproliferative diseases. J. Clin. Invest.117, 524–529 (2007).

Disclosure of Interests:

Sofie Falkenløve Madsen Employee of: Nordic Bioscience and University of Copenhagen, Anne Sofie Siebuhr Employee of: Nordic Bioscience A/S, Henrik Jessen: None declared, Jannie Marie Bülow Sand Employee of: Nordic Bioscience A/S, Morten Karsdal Shareholder of: Nordic Bioscience A/S, Employee of: Nordic Bioscience A/S, Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Nordic Bioscience A/S

POS0955 EXTRACELLULAR MATRIX PROTEIN TURNOVER MARKERS ARE ASSOCIATED WITH axSpA – A COMPARISON WITH CONTROL SUBJECTS WITH OR WITHOUT PELVIC, BUTTOCK OR 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. Tissue-derived extracellular (ECM) markers quantified in serum may serve to differentiate axSpA patients from other diagnostic entities.

Objectives:

To investigate circulating ECM turnover markers as potential biomarkers to differentiate patients with axSpA from a control group of subjects with buttock or pelvic pain attributed to other reasons, including postpartum women and healthy subjects.

Methods:

Biomarkers of ECM degradation/chronic inflammation (C1M, C3M, C4M, C6M, CRPM, C10C and COL10NC) and ECM formation (PRO-C3 and PRO-C6) were measured in 204 participants from the MASH study [1] (Table 1). Biomarker levels were compared among patients with axSpA and control group, and two new variables (Type 3 and Type 6) were included, corresponding to the index of formation/degradation of type III and type VI collagen respectively. The biomarker data was log10 transformed for normalization when necessary and linear regression models with pairwise comparisons were performed. Clinical scores and the SPARCC MRI scores for sacroiliac joint (SIJ) inflammation were correlated with the biomarkers data (data not shown).

Table 1.

Comparison of blood-tested biomarkers levels in MASH study. Data was adjusted for confounders age, gender, and body mass index (BMI).

Biomarkers(Mean (SD))Patientswith axSpA(n = 41)Control groups (n=163)pC1M84.3 (85.8)36.2 (22.1)<0.0001C3M15.6 (4.0)13.9 (3.0)0.011C4M34.9 (10.2)27.9 (7.7)<0.0001C6M20.5 (5.8)17.4 (4.2)<0.0001CRPM11.9 (2.9)11.0 (5.9)0.027C10C2567 (462)2568 (560)0.31COL10NC9.15 (5.81)9.43 (8.27)0.43PRO_C310.2 (2.5)11.3 (3.0)0.0052PRO_C66.94 (2.45)6.86 (2.53)0.93Type 3 (PRO-C3/C3M)0.70 (0.28)0.86 (0.31)0.0004Type 6 (PRO-C6/C6M)0.36 (0.16)0.41 (0.14)0.0024

Results:

We found that patients with axSpA had significantly increased MMP-mediated degradation of type I (C1M), type III (C3M), type IV (C4M) and type VI (C6M) collagens (p<0.0001, p=0.01,p<0.001,p<0.001, respectively), and CRP-metabolite (CRPM, p=0.027), and significantly decreased formation of type III collagen (p= 0.052) compared with control groups when adjusting for age, gender and body mass index (BMI). Significantly decreased rates of Type 3 and Type 6 variables were also observed in patients with axSpA (p=0.004, p=0.002, respectively). We further adjusted the analyses by the SPARCC SIJ inflammation scores since differences in these were found among the two groups [1], and similar differences in biomarker levels were found, indicating that the relationship between the level of biomarkers and the SPARCC SIJ inflammation scores was independent between the two groups.

Conclusion:

Biomarkers of type I, III, IV and V collagen and a CRP-metabolite showed an altered turnover in patients with axSpA compared with the control group including subjects with or without buttock or pelvic pain attributable to other reasons. Such biomarkers may be used in combination with MRI or independently to separate patients with axSpA from other back pain conditions.

References:

[1]Seven, S., Østergaard, M., Morsel-Carlsen, L., Sørensen, I. J., Bonde, B., Thamsborg, G., ... & Pedersen, S. J. (2019). Magnetic Resonance Imaging of Lesions in the Sacroiliac Joints for Differentiation of Patients With Axial Spondyloarthritis From Control Subjects With or Without Pelvic or Buttock Pain: A Prospective, Cross-Sectional Study of 204 Participants. Arthritis & Rheumatology, 71(12), 2034-2046.

Acknowledgements:

The study was supported by Innovation Fund Denmark, Rigshospitalet and the Danish Rheumatism Association (grant no. R102-A2132-B98, R159-A5061 and R150-A4467-B98).

Disclosure of Interests:

Helena Port Employee of: Industrial PhD student at Nordic Bioscience and University of Copenhagen, Signe Holm Nielsen Employee of: Full time employee at Nordic Bioscience, Joseph Blair Employee of: Full time employee at Nordic Bioscience, Sofie Falkenløve Madsen Employee of: Full time employee at Nordic Bioscience A/S, Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Full time employee at Nordic Bioscience A/S, Morten Karsdal Shareholder of: Nordic Bioscience A/S, Employee of: Full time employee at Nordic Bioscience A/S, Sengül Seven: None declared, Inge Juul Sørensen: None declared, Lone Morsel-Carlsen: None declared, Mikkel Østergaard: None declared, Susanne Juhl Pedersen: None declared

POS0966 IDENTIFICATION OF PATIENTS AFFECTED WITH ANKYLOSING SPONDYLITIS AND INFLAMMATORY BOWEL DISEASE OVERLAP USING COLLAGEN BIOMARKERS

Background:

Chronic inflammatory arthritis is a hallmark of Ankylosing Spondylitis (AS), where co-existence of inflammatory bowel disease, such as Crohn’s Disease (CD) is prominent. The clinical overlap of AS and CD has raised the hypothesis that these conditions may have similar pathophysiological mechanisms. Both indications are characterized by an altered extracellular matrix turnover, where particularly collagens are remodeled.

Objectives:

We investigated the association between biomarkers of collagen degradation in healthy controls and patients with AS, CD and AS/CD overlap, with the aim to investigate the biomarkers’ ability to identify patients with AS/CD overlap.

Methods:

Patients with AS fulfilling ASAS criteria (n=13), biopsy-proven CD (n=14), subjects with AS and CD overlap (n=10) and healthy controls (n=11) undergoing standard of care colonoscopies were included in the study. The collagen degradation biomarkers measuring type III, IV, VI and X collagen (C3M, C4M, C6M and C10C, respectively) were measured in EDTA plasma samples from all subject groups. Biomarkers were measured by competitive ELISAs. Statistical analysis was performed using an ANCOVA adjusted for age, an AUROC analysis and spearman correlations.

Results:

The collagen biomarker C4M was significantly higher in patients with AS/CD overlap compared to AS, CD and HCs (all p<0.0001, Figure 1A). The blood levels of C4M in AS patients were significantly lower than HC (p=0.0003), while CD also showed a lower level compared to HC though not significant (p=0.0798). No difference was found between AS and CD alone. In an AUROC analysis, C4M showed a complete separation between the patients with AS/CD overlap compared to HC, AS and CD with an AUC=1.00; p=0.0001. No differences were found between the patient groups for C3M, C6M and C10C (Figure 1, B-D). 91.3 % of patients with AS, 92.8% of patients with CD and 60 % of patients with AS and IBD overlap were actively treated with TNF-α inhibitors, which may explain the suppression of the collagen degradation biomarker levels in AS, CD and AS/IBD overlap compared to healthy controls[1,2]. No correlations were found between the collagen biomarkers and CRP, BASDAI, SCCAI or HBI scores.

Conclusion:

Degradation of type IV collagen quantified by C4M showed a complete separation of patients with AS/IBD overlap, compared to AS, CD and HC patients, which indicates an excessive collagen degradation and epithelial turnover. This biomarker could potentially be used to identify patients affected by both manifestations, and guide treatment decisions.

References:

[1]van Haaften WT, Mortensen JH, Dige AK, Grønbæk H, Hvas CL, Bay-Jensen AC, et al. Serological Biomarkers of Tissue Turnover Identify Responders to Anti-TNF Therapy in Crohn’s Disease: A Pilot Study. Clin Transl Gastroenterol. 2020;11:e00217.

[2]Siebuhr AS, Bay-Jensen AC, Karsdal MA, Lories RJ, de Vlam K. CRP and a biomarker of type I collagen degradation, C1M, can differentiate anti-inflammatory treatment response in ankylosing spondylitis. Biomark Med. 2016;10:197–208.

Figure 1.

Levels of C4M (A), C3M (B), C6M (C) and C10C (D) in EDTA plasma from patients diagnosed with AS (n=13), CD (n=14), AS and CD overlap (n=10) and HC (n=11). Graphs are presented as Tukey box plots. Statistical significance: ****p<0.0001.

Disclosure of Interests:

Signe Holm Nielsen Employee of: Full time PostDoc at Nordic Bioscience and Technical University of Denmark, Andrew Stahly: None declared, Emilie H. Regner: None declared, Anne-Christine Bay-Jensen Shareholder of: Stocks at Nordic Bioscience, Employee of: Full-time employee at Nordic Bioscience, Morten Karsdal Shareholder of: Stocks at Nordic Bioscience, Employee of: Full-time employee at Nordic Bioscience, Kristine A. Kuhn: None declared.

AB0067 RHEUMATOID ARTHRITIS IS DRIVEN NOT ONLY BY INFLAMMATION BUT ALSO BY FIBROGENESIS

Background:

Rheumatoid arthritis (RA) is a chronic, autoimmune disease characterized by inflammation of the synovium, cartilage and bone leading to joint swelling, tenderness, and dysfunction. The destruction of the joint tissue involves degradation of the extracellular matrix (ECM). The ECM consist of collagens and other connective proteins1. Studies have shown that elevated levels of collagen metabolites, such as those of type I, II, III and VI, are highly elevated in RA, correlated to disease activity and modulated in response to, for example tocilizumab2, baricitinib3 and methotrexate4. However, little is known about the formation of collagen, fibroblast activity, the fibrotic component of RA and how this influence likelihood of response to treatment.

Objectives:

We investigated the level of active fibrogenesis in a population of moderate to severe RA patients (in contrast healthy controls) by assessing blood-levels of PRO-C3 and PRO-C6 (type III and VI collagen formation markers), which have been reported to be associated with the degree and extent of fibrosis5.

Methods:

PRO-C3 and PRO-C6 was measured in serum of 166 RA patients (age; 54 (20-82), 83 % females, 91% white) at baseline and week 16 after treatment with an anti-IL6 receptor antibody in combination with MTX, as well as in serum of 77 donors (age; 42 (20-69), 51 % females, 66% white). Marker data was LN transformed. A general linear model was used when comparing groups.

Results:

The serum fibrogenesis marker PRO-C3, but not PRO-C6, was significantly elevated in RA compared to donors (2.1 vs. 2.4 ≈ 30% difference, p<0.0001, fig. 1A). None of the markers were correlated with disease measures such as DAS28, CRP, VASpain. None of the markers were modulated significantly in response to treatment. Interestingly, PRO-C3 levels were significantly higher at in non-responders (resp.) at week 16 compared to resp. (2.8 vs. 2.4 ≈ 40% difference, p=0.0018, fig. 1C). Similar trend was observed for PRO-C6 (2.2 vs. 2.0 ≈ 20% difference, p=0.061 fig. 1D).

Conclusion:

Active fibrosis, with activated fibroblasts, may play an unseen role in RA. Patients will elevated levels of the fibrosis markers PRO-C3 and PRO-C6 were less likely to respond to an anti-IL6R. This may also give clue why such treatment are less efficacious in diseases with a clear fibrotic component.

References:

[1]Karsdal et al. Rheumatoid arthritis: A case for personalized health care? ACR 2014; 66: 1273–80.

[2]Bay-Jensen et al. Effect of tocilizumab combined with methotrexate on circulating biomarkers of synovium, cartilage, and bone in the LITHE study. SAR 2014; 43: 470–8.

[3]Thudium et al. The Janus kinase 1/2 inhibitor baricitinib reduces biomarkers of joint destruction in moderate to severe rheumatoid arthritis. ART 2020; 22.

[4]Drobinski et al. Connective tissue remodeling is differently modulated by tocilizumab versus methotrexate monotherapy in patients with early rheumatoid arthritis: the AMBITION study. ART 2021; 23.

[5]Karsdal et al. Profiling and targeting connective tissue remodeling in autoimmunity - A novel paradigm for diagnosing and treating chronic diseases. AutoRev 2021; 20.

Disclosure of Interests:

None declared

A case report of pregnancy in untreated alkaptonuria - Focus on urinary tissue remodelling markers

A 34-year old woman with alkaptonuria had an elective pregnancy, during which she collected urine samples over the duration of her pregnancy until parturition. She had been attending the National Alkaptonuria Centre from the age of 31 years and continued to attend after delivery for a further three annual visits. Data from her NAC visits as well as urine samples collected during pregnancy were analysed. Urine CTX-1/urine creatinine, urine αCTX-I/ urine creatinine, urine CTX-II/ urine creatinine, and urine C3M/urine creatinine all showed a rapid increase early in pregnancy, returning to baseline before increasing in late pregnancy, indicating significant remodelling of bone, subchondral bone, cartilage and other organs and connective tissue rich in collagens I, II and III. The pattern of tissue remodelling in AKU pregnancy has been described for the very first time. Further research is needed to understand pregnancy in AKU.

SAT0298 IS INTERLEUKIN 6 A FACTOR OF FIBROGENESIS IN DERMAL FIBROBLASTS?

Background:

Interleukin 6 (IL-6) is known to have both pro- and anti-inflammatory properties, depending on the receptor activation. The classical IL-6 signaling via the membrane bound receptor is mainly anti-inflammatory, whereas signaling through the soluble receptor (sIL-6R) is pro-inflammatory/pro-fibrotic. However, the direct fibrotic effect of IL-6 stimulation on dermal fibroblasts is unknown.

Objectives:

We investigated the fibrotic effect of IL-6 + sIL-6R in a dermal fibroblast model and assessed fibrosis by neo-epitope biomarkers of extracellular matrix proteins.

Methods:

Primary healthy human dermal fibroblasts were grown for up to 17 days in DMEM medium with 0.4% fetal calf serum, ficoll (to produce a crowded environment) and ascorbic acid. IL-6 [1-90 nM]+sIL-6R [0.1-9 nM] alone or in combination with TGFβ [1 nM] were tested in three different donors. TGFβ [1 nM], PDGF-AB [3 nM] and non-stimulated cells (w/o) were used as controls. Tocilizumab (TCZ) with TGFβ + IL-6 + sIL-6R stimulation was tested in one donor. Collagen type I, III and VI formation (PRO-C1, PRO-C3 and PRO-C6) and fibronectin (FBN-C) were evaluated by validated ELISAs (Nordic Bioscience). Western blot analysis investigated signal cascades. Gene expression of selected ECM proteins was analyzed. Statistical analyses included One-way and 2-way ANOVA and area under the curve analysis.

Results:

formation by the end of the culture period. The fibronectin and collagen type VI signal were consistent between the three tested donors, whereas the formation of type III collagen was only increased in one donor, but in several trials. Type I collagen formation was unchanged by IL-6 + sIL-6R stimulation. The gene expression of type I collagen was induced by IL-6 + sIL-6R. Western blot analysis validated trans-signaling by the IL-6+sIL-6R stimulation as expected.

IL-6 + sIL-6R stimulation in combination with TGFβ decreased fibronectin levels compared to TGFβ alone but did not reach the level of unstimulated fibroblasts. The formation of collagen type IV was generally unchanged with IL-6 + sIL-6R + TGFβ compared to TGFβ alone. Collagen type I and III formation was more scattered in the signals when IL-6 + sIL-6R was in combination with TGFβ, as the biomarker level could be either decreased or increased compared to TGFβ alone. In two studies the type I collagen level was synergistic increased by IL-6 + sIL-6R + TGFβ, whereas another study found the level to be decreased compared to TGFβ alone. The gene expression of fibronectin and type I collagen was increased with TGFβ +IL-6+sIL-6R compared to TGFβ alone.

Inhibition of IL-6R by TCZ in combination with IL-6 + sIL-6R did only decrease the fibronectin level with the lowest TCZ concentration (p=0.03). TCZ alone decreased the fibronectin level in a dose-dependent manner (One-way ANOVA p=0.0002).

Conclusion:

We investigated the fibrotic response of dermal fibroblasts to IL-6 + sIL-6R stimulation. IL-6 modulated the fibronectin level and modulated the collagen type III formation level in a somewhat dose-dependent manner. In combination with TGFβ, IL-6 decreased collagen type I and IV formation and fibronectin. However, in this study inhibition of IL-6R by TCZ did not change the fibrotic response of the dermal fibroblasts. This study indicated that IL-6 did not induce collagen formation in dermal fibroblasts, except type III collagen formation with high IL-6 concentration.

Figure:

Disclosure of Interests:

Anne Sofie Siebuhr Employee of: Nordic Bioscience, Pernille Juhl Employee of: Nordic Bioscience, Morten Karsdal Shareholder of: Nordic Bioscience A/S., Employee of: Full time employee at Nordic Bioscience A/S., Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Full time employee at Nordic Bioscience A/S.

FRI0404 SEPERATION OF HIGH AND LOW RESPONSE GROUPS IN OSTEOARTHRITIS USING SERUM CARTILAGE DEGRADATION AND FORMATION MARKERS – A 3 YEAR FOLLOW-UP ON THE FORWARD STUDY TESTING THE EFFICACY OF SPRIFERMIN

Background:

In osteoarthritis (OA), response to different interventions could be more pronounced in different endotypes of cartilage turnover. Data from UK biobank suggest that an endotype of low cartilage repair is associated with structural progression in osteoarthritis (OA)[1]. Sprifermin a truncated and recombinant FGF18 have been shown to induce chondrocyte proliferation and cartilage formation in in vitro settings[2–4]. Efficacy on cartilage thickness in OA was recently demonstrated in the FORWARD study[5].

Objectives:

We investigated markers of cartilage formation (serum PRO-C2) and degradation (urine CTX-II), to assess profiles indicative of chondrocyte metabolic activity would be associated with both structural and symptomatic responses to sprifermin.

Methods:

Serum and urine from participants of the FORWARD study, a phase II clinical trial testing the efficacy of intra-articular (IA) sprifermin, were collected throughout the study. Clinical data recorded at baseline, year 2 and year 3 follow-up were used, including cartilage thickness and WOMAC. All available baseline samples of the placebo and treatment arms were assessed for serum PRO-C2 and urinary CTX-II. Patients were separated into dichotomized groups based on 33, 50 or 66 percentiles cut-points and two-year treatment responses were compared in a prospective-retrospective statistical design manner.

Results:

Patients with low baseline PRO-C2 (<66%), in the 100ug/4x treatment arm, had greater difference to placebo in cartilage thickness as compared to the high PRO-C2 and all-comers groups (0.06 vs 0.03 and 0.05 mm, respectively) at two and three years (Fig.). Similar effect was seen for low CTX-II (<50%) (0.07 vs -0.03 and 0.05 mm, respectively). In addition, the WOMAC placebo effect was reduced in the low PRO-C2 and the low CTX-II groups, resulting in a difference compared to placebo of -0.81vs. 1.35 (low vs high proC2 and -2.35 vs 1.47 (low vs high CTX-II).

Conclusion:

We noticed that low baseline PRO-C2 and CTX-II indicative for low metabolic activity of chondrocytes were associated with improved symptomatic outcome and slightly increased cartilage thickness compared to high metabolic activity. The parallelism between PRO-C2 and CTX-II point towards the existence of a low cartilage repair endotype and might reflect a subgroup of patients with higher sensitivity towards interventions - an effect that was maintained over three years.

References:

[1]Tachmazidou I, et al. ”Identification of new therapeutic targets for osteoarthritis through genome-wide analyses of UK Biobank data.” Nat Genet 2019;51:230–6.

[2]Gigout A, et al. ”Sprifermin (rhFGF18) enables proliferation of chondrocytes producing a hyaline cartilage matrix”. Osteoarthr Cartil. 2017;25.

[3]Reker D et al. “Sprifermin (rhFGF18) modulates extracellular matrix turnover in cartilage explants ex vivo”. J Transl Med. 2017;15.

[4]Luo Y et al. ”A Novel High Sensitivity Type II Collagen Blood-Based Biomarker, PRO-C2, for Assessment of Cartilage Formation”. Int J Mol Sci 2018;19:3485.

[5]Hochberg MC et al. “Effect of Intra-Articular Sprifermin vs Placebo on Femorotibial Joint Cartilage Thickness in Patients With Osteoarthritis”. JAMA. 2019; Oct 8;322(14).

Disclosure of Interests:

Hans Gühring Employee of: Merck KGaA, Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Full time employee at Nordic Bioscience A/S., Flavie Moreau Employee of: Merck KGaA, Jeppe Ragnar Andersen Shareholder of: Nordic Bioscience A/S., Employee of: Full time employee of Nordic Bioscience., Asger Reinstrup Bihlet Shareholder of: Nordic Bioscience A/S., Morten Karsdal Shareholder of: Nordic Bioscience A/S., Employee of: Full time employee at Nordic Bioscience A/S.

AB0167 TOFACITINIB AND NINTEDANIB MODULATE COLLAGEN FORMATION IN DERMAL FIBROBLASTS

Background:

Dermal fibroblasts are responsible for the excessive extracellular matrix (ECM) formation observed in the skin of systemic sclerosis (SSc) patients and fibroblasts are therefore an obvious target for anti-fibrotic treatments. TGFβ, PDGF and IL-6 are known to be central cytokines in systemic sclerosis. Nintedanib, a tyrosine-kinase inhibitor approved for treatment of idiopathic pulmonary fibrosis, did not show effect on dermal fibrosis only on pulmonary fibrosis in SSc patients with interstitial lung disease (ILD). Tofacitinib, as Pan JAK inhibitor, has shown to inhibit dermal fibrosis in mouse models and shown positive indications in patients.

Objectives:

We investigated the direct effect of Nintedanib and Tofacitinib on ECM production from human dermal fibroblast using translational biomarkers of type I, III and VI collagens and fibronectin.

Methods:

Primary healthy human dermal fibroblasts were grown in DMEM media containing 0.4% fetal calf serum, Ficoll (to produce a crowded environment) and ascorbic acid for up to 17 days. The cells were stimulated with PDGF [3 nM] and/or TGFβ [1 nM] in combination with Nintedanib [1 nM-10 μM] treatment initiated at day 0 or 7 or Tofacitinib [3-100 nM] treatment initiated at culture start together. Media and treatments were changed twice a week. Non-activated cells (w/o) were used as control. Type I, III and VI collagen formation (PRO-C1, PRO-C3 and PRO-C6, respectively) and fibronectin (FBN-C) were evaluated by validated ELISAs (Nordic Bioscience). Statistical analysis included 1-way and 2-way ANOVA, AUC and Mann-Whitney U-test.

Results:

PDGF significantly increased collagen type III and VI formation and collagen type I formation minimally. PDGF did not induce changes in fibronectin levels. TGFβ increased collagen type I and VI formation but did not induce formation of collagen type III. TGFβ increased fibronectin levels, where PDGF did not.

Nintedanib (≥100 nM) added either from day 0 or 7 reduced PDGF induced collagen type III and VI formation to the levels of w/o throughout the remainder of the study. In TGFβ treated fibroblasts, Nintedanib added either from day 0 or 7 reduced collagen type I and VI formation. The fibronectin levels were dose-dependently reduced by Nintedanib. The biomarker levels were at study end at the level of w/o. Nintedanib at a concentration of 1 uM and higher significantly decreased the biomarker levels. Nintedanib (≥100 nM) in fibroblasts stimulated with both TGFβ and PDGF significantly reduced collagen type I, III and VI collagen and fibronectin.

A Tofacitinib concentration of 100 nM was toxic to the dermal fibroblasts as the cell viability was minimal at culture end. However, the viability of Tofacitinib (100 nM) in combination with TGFβ was decreased at study end, but only to half the viability of untreated cells. Tofacitinib dose-dependently decreased the TGFβ induced type I and III collagen formation and fibronectin in the dermal fibroblasts. Tofacitinib (100 nM) decreased the level of collagen type I and III formation to the level of w/o, where as the level of fibronectin was lowered by 80 % of TGFβ. Tofacitinib as low as 12.5 nM significantly lowered the collagen type I formation and fibronectin (both p<0.05) and Tofacitinib of 25 nM decreased collagen type III formation significantly (p<0.0001).

Conclusion:

Tofacitinib decreased the formation of the collagens and fibronectin. Nintedanib inhibited ECM production differently in PDGF and TGFβ induced dermal fibroblast, but in the combination of TGFβ and PDGF Nintedanib significantly decreased the ongoing fibrosis. In PDGF induced fibrosis, Nintedanib acted as an on-off switch, whereas the inhibition was dose-dependent in TGFβ induced fibrosis. This cell study indicates that Nintedanib and Tofacitinib inhibits collagen production in dermal fibroblasts.

Figure:

Disclosure of Interests:

Anne Sofie Siebuhr Employee of: Nordic Bioscience, Morten Karsdal Shareholder of: Nordic Bioscience A/S., Employee of: Full time employee at Nordic Bioscience A/S., Pernille Juhl Employee of: Nordic Bioscience, Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Full time employee at Nordic Bioscience A/S.

THU0057 A NEO-EPITOPE FRAGMENT OF CARTILAGE DEGRADATION GENERATED FROM TYPE II COLLAGEN PROCESSING: A NOVEL SERUM BIOMARKER TO ACCESS TYPE II COLLAGEN DEGRADATION IN JOINT DEGENERATIVE DISEASES

Background:

Altered extracellular matrix (ECM) remodelling is an important part of the pathology seen in joint degenerative diseases. Type II collagen is the most abundant ECM protein in the cartilage and provides the tissue with essential tensile strength in order to withstand high compressive loading. During cartilage erosion, type II collagen is cleaved by matrix metallopeptidases (MMPs) which generates new protein fragments called neo-epitopes. These fragments are released into circulation and may potentially serve as biomarkers by indicating the degree of cartilage destruction.

Objectives:

The aim of this study is to develop a highly specific immunoassay targeting a neo-epitope fragment of type II collagen cleaved, named T2CM. Moreover, we investigated the assays potential to evaluate type II collagen degradation in anex vivobovine full-depth cartilage explants model (BEX) with catabolic treatment and in healthy controls and osteoarthritis (OA) patients.

Methods:

A monoclonal antibody was raised in mouse against the C-terminus from protease cleavage site of type II collagen and a direct competitive ELISA was developed and technically validated. The assay specificity was evaluated for the standard peptide excluding cross-reactivity with elongated and truncated peptides, and a non-sense coating peptide. Human OA cartilage was cleaved with MMP-1, -2, -9 and -13 and measured with the T2CM-assay to investigate which MMPs generated the neo-epitope. T2CM levels were measured in supernatant from BEX explants cultured for 21 days in serum free DMEM/F12 medium with six different doses of OSM+TNF-α (O+T) treatment (20/10, 20/20, 20/40, 10/10, 10/20, 10/40 ng/mL) including a control group without (w/o) treatment. The supernatant was harvested 3 times weekly and replaced with new culture medium with O+T treatment. Biomarker results were confirmed by western blot, where T2CM was measured in supernatant from explants with O+T treatment 20/20 ng/mL and 20/40 ng/mL harvested on day 14 and day 21. To confirm the preclinical data, serum samples from 23 healthy controls (age range from 44-59 years with mean 51.4 ± SD 5.1, gender distribution was 56% female and 44% male, and 100% Caucasian) and 23 OA patients (age range from 41-77 years with mean 57.7 ± SD 13.7, gender distribution was 61% female and 39% male, and 100% Caucasian) were measured by T2CM.

Results:

A technically robust and T2CM-specific assay was developed. The assay linearity and spike-recovery were accepted with percentage of 99.69% and 93.15%. The assay showed no cross-reaction with the elongated, truncated or non-sense coating peptide. In addition, it was demonstrated that the T2CM neo-epitope was derived from MMP-1 and MMP-13 cleavage of type II collagen. O+T treatment induced the T2CM release in BEX compared to the untreated (Figure 1-2). Moreover, the western blot confirmed the T2CM results by the presence of two T2CM bands on day 21 from O+T treated explant compared to day 14 where no bands appeared. T2CM showed to be significantly elevated in patients with OA compared to controls (p=0.036; mean 3.262 ng/mL ± SD 1.065 vs 2.698 ng/mL ± SD 1.118).

Conclusion:

The newly developed assay was specific for the T2CM neo-epitope and was determined to be generated by MMP-1 and MMP-13. Additionally, the assay detected elevated levels of T2CM in supernatant from explants treated with O+T after 19 days of treatment compared to untreated. This was further confirmed in human OA patients, where the level of T2CM was elevated compared to healthy controls. This suggests that T2CM may have potential as biomarker for type II collagen degradation. Future preclinical and clinical studies are needed to validate these findings.

Figure 1-2.

T2CM measurements in BEX model. OSM + TNF-a (O+T) ng/mL.

Disclosure of Interests:

Solveig Skovlund Groen Employee of: Nordic Bioscience, Dovile Sinkeviciute Grant/research support from: Industrial PhD Student, Employee of: Industrial PhD Student, Christian Thudium Employee of: Employee at Nordic Bioscience A/S., Patrik Önnerfjord: None declared, Morten Karsdal Shareholder of: Nordic Bioscience A/S., Employee of: Full time employee at Nordic Bioscience A/S., Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Full time employee at Nordic Bioscience A/S., Signe Holm Nielsen Employee of: Full time employee at Nordic Bioscience

OP0252 CIRCULATING COLLAGEN TURNOVER MARKERS ARE SPECIFICALLY CHANGED IN VERY EARLY SYSTEMIC SCLEROSIS

Background:

Timely diagnosis of patients with very early systemic sclerosis (veSSc) is essential for their personalized and optimal management. We hypothesise that changes in serum-based extracellular matrix (ECM) turnover biomarkers are already detectable in patients with veSSc, even before occurrence of specific clinical signs.

Objectives:

To investigate circulating ECM turnover markers as potential biomarkers for veSSc.

Methods:

Patients with veSSc, n=42, defined as presence of Raynaud’s syndrome and at least one of puffy fingers, positive antinuclear antibodies or pathological nailfold capillaroscopy, who did not meet any classification criteria for SSc, were compared to healthy controls (HC, n=29). Longitudinal assessment, data and sera collection were conducted by EUSTAR standards. ECM-degradation (BGM, C3M, C4M, C6M) and ECM-formation biomarkers (PRO-C3, PRO-C4, PRO-C5) were measured in serum using ELISA assays. The statistical analyses included Mann-Whitney U, Spearman correlation and ROC analysis. Using Kaplan-Meier plots and univariable Cox regression, we explored if biomarkers can predict progression towards definite SSc (fulfillment of ACR/EULAR criteria or minimum two points increase in the criteria score) during the longitudinal follow-up.

Results:

Compared to HC, veSSc patients showed a deregulated turnover of type III and IV collagen, with higher degradation (higher C3M, C4M, both p<0.0001 and PRO-C3, p=0.004, Figure 1a, resulting in lower turnover ratios PRO-C3/C3M and PRO-C4/C4M, both p<0.0001). The biglycan degradation biomarker BGM was also higher in veSSc (p=0.006), whereas the degradation biomarker for type VI collagen, C6M, was lower than in HC (p=0.002). In the ROC analysis, biomarkers of type III and IV collagen distinguished between veSSc and HC: C3M, AUC=0.95, p<0.0001; C4M, AUC=0.97, p<0.0001; turnover ratios PRO-C3/C3M, AUC=0.80, p<0.0001; PRO-C4/C4M, AUC=0.97; p<0.0001 (Figure 1b).

Median follow up was 4.5 years (range 0.5-7.9 years), mean age was 50±2.2 years, 88% female gender, 24% with puffy fingers, 92% were ANA positive, 64% had an abnormal capillaroscopy, none had organ involvement or skin fibrosis. 14/42 veSSc patients fulfilled the ACR/EULAR classification criteria at follow-up (time to fulfilment of criteria ranged between 0.5 and 6.8 years from inclusion) and in addition, 18/42 veSSc patients gained at least two classification criteria-points. This resulted in 14, respectively 18 progressors for the longitudinal analysis. However, in univariable Cox regression, the baseline levels of the markers did not predict progression over time.

Conclusion:

ECM turnover is already altered in veSSc patients compared to HC. Biomarkes of type III and IV collagen distinguished between veSSc patients and HC, which may indicate them as potential biomarkers for the detection of veSSc in addition to the established immunological and capillaroscopic criteria.

Disclosure of Interests:

Rucsandra Dobrota: None declared, Suzana Jordan: None declared, Pernille Juhl Employee of: Nordic Bioscience, Britta Maurer Grant/research support from: AbbVie, Protagen, Novartis, congress support from Pfizer, Roche, Actelion, and MSD, Speakers bureau: Novartis, Mike O. Becker: None declared, Carina Mihai: None declared, Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Full time employee at Nordic Bioscience A/S., Morten Karsdal Shareholder of: Nordic Bioscience A/S., Employee of: Full time employee at Nordic Bioscience A/S., Anne Sofie Siebuhr Employee of: Nordic Bioscience, Oliver Distler Grant/research support from: Grants/Research support from Actelion, Bayer, Boehringer Ingelheim, Competitive Drug Development International Ltd. and Mitsubishi Tanabe; he also holds the issued Patent on mir-29 for the treatment of systemic sclerosis (US8247389, EP2331143)., Consultant of: Consultancy fees from Actelion, Acceleron Pharma, AnaMar, Bayer, Baecon Discovery, Blade Therapeutics, Boehringer, CSL Behring, Catenion, ChemomAb, Curzion Pharmaceuticals, Ergonex, Galapagos NV, GSK, Glenmark Pharmaceuticals, Inventiva, Italfarmaco, iQvia, medac, Medscape, Mitsubishi Tanabe Pharma, MSD, Roche, Sanofi and UCB, Speakers bureau: Speaker fees from Actelion, Bayer, Boehringer Ingelheim, Medscape, Pfizer and Roche

SAT0299 PROLIFERATION, MIGRATION AND CONTRACTION ARE DIFFERENT BETWEEN TGFΒ AND PDGF STIMULATED DERMAL FIBROBLASTS

Background:

Systemic sclerosis has vascular, inflammatory and fibrotic components, which may be associated with different growth factors and cytokines. Platelet derived growth factor (PDGF) is associated with the vasculature, whereas tumor necrosis factor beta (TGFβ) is associated with inflammation and fibrosis. We have developed a fibroblast model system of dermal fibrosis for anti-fibrotic drugs testing, but the effect of the fibroblasts mechanistic properties are unknown.

Objectives:

We investigated different mechanical capacities of PDGF and TGFβ treated human healthy dermal fibroblasts in the SiaJ setting.

Methods:

Primary human healthy dermal fibroblasts were grown in DMEM medium containing 0.4% fetal calf serum, ficoll (to produce a crowded environment) and ascorbic acid for up to 17 days. A wound was induced by scratching the cells at 0, 1, 3 or 7 days after treatment initiation. Wound closure was followed for 3 days. Contraction capacity was tested by creating gels of human fibroblasts produced collagens containing dermal fibroblasts and contraction was assessed at day 2 by calculating the percentage of gel size to total well size. Collagen type I, III and VI formation (PRO-C1, PRO-C3 and PRO-C6) and fibronectin (FBN-C) were evaluated by validated ELISAs (Nordic Bioscience). Gene expression was analyzed after 2 days in culture. Statistical analyses included One-way ANOVA and student’s t-test.

Results:

Generally, PDGF closed the wound in half the time of w/o and TGFβ, when treatment and cells are added concurrently or scratched one day after treatment initiation. When treatments were added 3 or 7 days prior to scratch, the cells treated with PDGF had proliferated to a higher degree than w/o and TGFβ. A consequence of this, was that when cells were scratch the sheet of cells produced was lifted from the bottom and fold over itself, leaving a much greater scratch than in the other treatments. However, despite this increased gap the PDGF treated cells closed the wound at the same time as w/o and TGFβ, confirming the results of the cells scratched at day 0 and 1.

Inhibition of contraction by ML-7 of otherwise untreated cells inhibited contraction significantly compared to untreated cells alone (p=0.0009). Contraction was increased in both TGFβ and PDGF treated cells compared to untreated cells (both p<0.0001). TGFβ+ ML-7 inhibited the contraction to the level of w/o (p=0.0024), which was only 35% of ML-7 alone. In the contraction study the cells were terminated after 2 days of culture, thus prior to when biomarker of ECM remodeling is usually assessed. However, FBN-C was detectable and a significant release of fibronectin by TGFβ and PDGF compared to w/o was found in the supernatant (both p<0.0001). The gene expression of FBN was only increased with TGFβ (p<0.05) and not PDGF. ML-7 alone tended to decrease FBN-C and in combination with TGFβ the FBN level was significantly decreased compared to TGFβ alone (p<0.0001). However, the level of TGFβ+ML-7 was significantly higher than ML-7 alone (p=0.038).

TGFβ increased the gene expression of most genes assessed, except Col6a1. PDGF increased the gene expression of Col3a1, Col5a1 and Col6a1 above the critical fold change of 2, but only significantly in Col5a1 and Col6a1 (both p<0.05).

Conclusion:

This study demonstrates that TGFβ and PDGF have different mechanical capacities in human healthy dermal fibroblasts; TGFβ increased gene expression of ECM related genes, such as collagens and have increased FBN release in the supernatant already 2 days after initial treatment. PDGF has increased contraction, proliferation and migratory capacities and less expression of ECM related genes and proteins.

Disclosure of Interests:

Anne Sofie Siebuhr Employee of: Nordic Bioscience, Sofie Falkenløve Madsen: None declared, Morten Karsdal Shareholder of: Nordic Bioscience A/S., Employee of: Full time employee at Nordic Bioscience A/S., Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Full time employee at Nordic Bioscience A/S., Pernille Juhl Employee of: Nordic Bioscience

OP0189 ASSESSMENT OF CARTILAGE DEGRADATION AND PROTECTIVE MARKERS IN SYNOVIAL FLUID FROM OSTEOARTHRITIS PATIENTS BEFORE AND AFTER CYCLES OF INTRA-ARTICULAR INJECTIONS WITH SPRIFERMIN

Background:

It is challenging to monitor treatment effects after intra-articular (IA) injection with tissue modifying drugs. Assessment of biomarker levels in synovial fluid may be one solution to the challenge. Sprifermin is a truncated form of fibroblast growth factor (FGF) 18 known to induce chondrocyte proliferation and type II collagen formation [1,2]. Data from preclinical investigations show that cartilage formation happens in different phases after therapy with sprifermin, starting with a phase of cartilage degradation during the induction of proliferation of chondrocytes followed by a phase of cartilage formation/production of extracellular matrix.

Objectives:

The aim was to investigate the effect of IA administrated sprifermin on cartilage turnover activity as compared to placebo in the injected joint by measurement of markers using longitudinal synovial fluid samples of patients participating in the FORWARD study.

Methods:

Each included patient had baseline and at least one FU sample available. Synovial fluid (SF) from participants receiving injections at three consecutive weeks in six month intervals through to week (wk) 80 (fig.A) available from the phase II clinical trial evaluating the efficacy and safety of intraarticularly delivered sprifermin [3] were selected for the investigations. Biochemical markers were measured in available SF samples of the placebo (containing saline IA, n=38) and the highest sprifermin dose group (100 mcg/IAx4, n=59). Samples were pretreated with ultrasound and centrifugation to decrease viscosity. Markers measured were PRO-C2 (type II collagen formation), huARGS (aggrecan degradation), and FBN-C (fibronectin). Markers are technically validated for synovial fluid measurement. Data were individually normalized to baseline to investigate the median proportional change over time.

Results:

Baseline mean (SD) levels of the markers in SF at BL were: PRO-C2, 21.4 (13.6) ng/mL, huARGS, 1117 (516) pM and FBN-C, 2556 (1959) ng/mL. PRO-C2 was initially decreased (from BL to wk 2) after injection with sprifermin; however, the level was increased at the beginning of each new injection cycle followed by a decrease after injection of sprifermin (Fig.B). Overall synovial PRO-C2 levels increased over time in therapy with sprifermin, while no change was observed for the placebo arm. huARGS showed a similar pattern as PRO-C2 – there was an overall increase in ARGS over time in the sprifermin group (fig.C). Interestingly ARGS continuously decreased over time in the placebo group. FBN-C is continuously increased after injection’s cycles, whereas no effect was seen in the placebo group (fig.D).

Conclusion:

Confirmatory of the preclinical investigations a biphasic response on cartilage turnover after injection with sprifermin was observed. Biochemical indications of cartilage formation and chondrocyte proliferation was only modulated in the sprifermin group, and cartilage degradation (ARGS) was temporal induced and reduced by sprifermin and placebo injections, respectively.

References:

[1]Gigout A, et al. “Sprifermin (rhFGF18) enables proliferation of chondrocytes producing a hyaline cartilage matrix”. Osteoarthr Cartil. 2017;25.

[2]Reker D, et al. “Sprifermin (rhFGF18) modulates extracellular matrix turnover in cartilage explants ex vivo”. J Transl Med. 2017;15.

[3]Hochberg MC, et al. “Effect of Intra-Articular Sprifermin vs Placebo on Femorotibial Joint Cartilage Thickness in Patients With Osteoarthritis”. JAMA. 2019; Oct 8;322(14).

Disclosure of Interests:

Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Full time employee at Nordic Bioscience A/S., Angela Manginelli Employee of: Merck KGaA, Flavie Moreau Employee of: Merck KGaA, Yi He Employee of: YH is a full time employee of Nordic Bioscience A/S, Yunyun Luo Employee of: Nordic Bioscience A/S, Jeppe Ragnar Andersen Shareholder of: Nordic Bioscience A/S., Employee of: Full time employee of Nordic Bioscience., Asger Reinstrup Bihlet Shareholder of: Nordic Bioscience A/S., Morten Karsdal Shareholder of: Nordic Bioscience A/S., Employee of: Full time employee at Nordic Bioscience A/S., Hans Gühring Employee of: Merck KGaA, Christoph Ladel Employee of: Merck KGaA

AB1242 A NOVEL BIOMARKER OF MMP-CLEAVED PROLARGIN IS ELEVATED IN PATIENTS WITH PSORIATIC ARTHRITIS COMPARED TO OTHER FIBRO-INFLAMMATORY DISEASES

Background:

Psoriatic Arthritis (PsA) is a chronic inflammatory disease, characterized by involvement of skin, axial and peripheral skeleton. Prolargin is a class II small leucine-rich proteoglycan found to be expressed in connective tissues of patients with PsA, and previously suggested to be remodelled upon treatment. Fragments of prolargin could quantify tissue turnover in individuals with PsA and reflect pathological tissue changes in these patients.

Objectives:

This study aimed at developing an immunoassay targeting a neo-epitope of prolargin cleaved by matrix metalloproteinases (MMPs), named PROM; and measure PROM levels in serum from two cohorts of patients affected by PsA and healthy controls.

Methods:

Development of a novel immunoassay targeting a specific MMP-generated neo-epitope fragment of prolargin (PROM) together with technical validation was performed, and then evaluated in serum from two independent cohorts. The technical validation included inter- and intra-variation, linearity, spiking recovery, stability and specificity. Specificity was tested using an elongated peptide, a truncated peptide and a non-sense peptide. The Discovery Cohort consists of 13 healthy individuals and 11 PsA patients, mean age 58, 60.3% female and 100% caucasian. The Validation Cohort included 35 healthy individuals and 112 PsA patients with low disease activity included in a 24-week randomized, double-blind, placebo-controlled trial of 3g n-3 polyunsaturated fatty acids (PUFA), a cohort of patients diagnosed with PsA by the CASPAR criteria. These patients had a mean age of 50.8, 57.8 % female and 100 % caucasian. Clinical variables and serum samples were collected at baseline and after 24 weeks of follow-up. An unpaired t-test was used for evaluation of healthy individuals and patients affected by PsA, while a paired t-test was used for evaluation of treatment at baseline and after 24 weeks.

Results:

A technically robust and specific assay was developed. The inter- and intra-assay variation of PROM was determined as 14% and 4 % respectively. PROM showed a good dilution recovery, spiking recovery, and storage /freeze-thaw stability (All, 100%±20%). PROM showed to be specific towards the targeted sequence, and did not show any reactivity towards the truncated peptide, elongated peptide or non-sense peptide. In the Discovery Cohort, serum levels of PROM were increased in patients with PsA compared to healthy individuals (p=0.032, Figure 1A). This increase was confirmed by the Validation Cohort, where PsA patients were significantly increased compared to healthy individuals at baseline (p=0.002, Figure 1B). After 24 weeks, the levels of PROM were unchanged in the n-3 PUFA treated group.

Figure 1.

Conclusion:

The novel biomarker PROM, reflecting connective tissue remodeling, is elevated in PsA patients compared to healthy controls in two independent cohorts. No significant association was found for PROM in a low disease activity group of PsA patients treated with n-3 PUFA.

References:

None

Acknowledgments:

We thank the Innovation Foundation and Danish Research Foundation for providing funding for this study.

Disclosure of Interests:

Dovile Sinkeviciute Grant/research support from: Industrial PhD Student, Employee of: Industrial PhD Student, Annette Schlemmer: None declared, Erik Berg Schmidt: None declared, Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Full time employee at Nordic Bioscience A/S., Morten Karsdal Shareholder of: Nordic Bioscience A/S., Employee of: Full time employee at Nordic Bioscience A/S., Jeppe Hagstrup Christensen: None declared, Salome Kristensen: None declared, Signe Holm Nielsen Employee of: Full time employee at Nordic Bioscience

Inflammation and joint destruction may be linked to the generation of cartilage metabolites of ADAMTS-5 through activation of toll-like receptors

OBJECTIVE

Links between pain and joint degradation are poorly understood. We investigated the role of activation of Toll-like receptors (TLR) by cartilage metabolites in initiating and maintaining the inflammatory loop in OA causing joint destruction.

METHODS

Synovial membrane explants (SMEs) were prepared from OA patients' synovial biopsies. SMEs were cultured for 10 days under following conditions: culture medium alone, OSM + TNFα, TLR2 agonist - Pam2CSK4, Pam3CSK4 or synthetic aggrecan 32-mer, TLR4 agonist - Lipid A. Release of pro-inflammatory and degradation biomarkers (acMMP3 and C3M) were measured by ELISA in conditioned media along with IL-6. Additionally, human cartilage was digested with ADAMTS-5, with or without the ADAMTS-5 inhibiting nanobody - M6495. Digested cartilage solution (DCS) and synthetic 32-mer were tested for TLR activation in SEAP based TLR reporter assay.

RESULTS

Western blotting confirmed TLR2 and TLR4 in untreated OA synovial biopsies. TLR agonists showed an increase in release of biomarkers - acMMP3 and C3M in SME. Synthetic 32-mer showed no activation in the TLR reporter assay. ADAMTS-5 degraded cartilage fragments activated TLR2 in vitro. Adding M6495 - an anti-ADAMTS-5 inhibiting nanobody®, blocked ADAMTS-5-mediated DCS TLR2 activation.

CONCLUSION

TLR2 is expressed in synovium of OA patients and their activation by synthetic ligands causes increased tissue turnover. ADAMTS-5-mediated cartilage degradation leads to release of aggrecan fragments which activates the TLR2 receptor in vitro. M6495 suppressed cartilage degradation by ADAMTS-5, limiting the activation of TLR2. In conclusion, pain and joint destruction may be linked to generation of ADAMTS-5 cartilage metabolites.

The intestinal tissue homeostasis - the role of extracellular matrix remodeling in inflammatory bowel disease

Introduction: Extracellular matrix (ECM) remodeling of the intestinal tissue is important in inflammatory bowel disease (IBD) due to the extensive mucosal remodeling. There are still gaps in our knowledge as to how ECM remodeling is related to intestinal epithelium homeostasis and healing of the intestinal mucosa.Areas covered: The aim of this review is to highlight the importance of the ECM in relation to the pathogenesis of IBD, while addressing basement membrane and interstitial matrix remodeling, and the processes of wound healing of the intestinal tissue in IBD.Expert opinion: In IBD, basement membrane remodeling may reflect the integrity of the intestinal epithelial-cell homeostasis. The interstitial matrix remodeling is associated with deep inflammation such as the transmural inflammation as seen in fistulas and intestinal fibrosis leading to fibrostenotic strictures, in patients with CD. The interplay between wound healing processes and ECM remodeling also affects the tissue homeostasis in IBD. The interstitial matrix, produced by fibroblasts, holds a very different biology as compared to the epithelial basement membrane in IBD. In combination with integration of wound healing, quantifying the interplay between damage and repair to these sub compartments may provide essential information in IBD patient profiling, mucosal healing and disease management.

Potential diagnostic value of a type X collagen neo-epitope biomarker for knee osteoarthritis

OBJECTIVE

Phenotypic changes of chondrocytes toward hypertrophy might be fundamental in the pathogenesis of osteoarthritis (OA), of which type X collagen (Col10) is a well-known marker. The purpose was to develop a specific immunoassay for blood quantification of a newly identified neo-epitope of type Col10 to assess its diagnostic value for radiographic knee OA.

METHODS

A neo-epitope of Col10 was identified in urine samples from OA patients. A monoclonal antibody against the neo-epitope was produced in Balb/C mice. The enzyme responsible for the cleavage was identified. Immunohistochemical detection of this neo-epitope was performed on human OA cartilage. An immunoassay (Col10neo) was developed and quantified in two clinical studies: the C4Pain-003 and the NYU OA progression study. Receiver operating characteristic curve (ROC) curve analysis was carried out to evaluate the discriminative power of Col10neo between OA and rheumatoid arthritis (RA).

RESULTS

A neo-epitope specific mAb was produced. The Cathepsin K-generated neo-epitope was localized to the pericellular matrix of chondrocytes, while its presence was extended and more prominent in superficial fibrillation in the cartilage with advanced degradation. In the C4Pain study, a higher level of Col10neo was seen in subjects with greater KL grade. The group of the highest tertile of Col10neo included more subjects with KL3-4. In the NYU study, Col10neo was statistically higher in OA than control or RA. ROC curve analysis revealed area under the curve was 0.88 (95% CI 0.81-0.94).

CONCLUSION

Our findings indicate that Col10neo linked to hypertrophic chondrocytes could be used as a diagnostic biochemical marker for knee OA.

Osteoarthritis year in review 2018: biomarkers (biochemical markers)

OBJECTIVE

The aim of this narrative review is to summarize important findings from biochemical marker studies relevant to osteoarthritis (OA) in the context of new discoveries and clinical and scientific need.

DESIGN

We conducted a systematic search of electronic medical databases (Embase, Medline, Web of Science, Cochrane central) between 01-03-2017 and 31-03-2018. The search was restricted to human studies, English language and full text available publications while reviews were excluded. Only papers describing protein based biomarkers measured in human body fluids (blood, urine and synovial fluid (SF)) were included. Of the 992 papers, 86 were reviewed here, with inclusion primarily based on relevance to OA biochemical markers.

RESULTS

This review highlights a selection of studies based on their quality and perceived importance to the field mainly including those that¹ evaluate prognostic value of biomarkers for OA progression (i.e., biomarkers reflecting change in composition of joint tissues and biomarkers of inflammation)², help in assessment of intervention efficacy, and³ are innovative and uncover new candidate biomarkers, or use new approaches in biomarker discovery.

CONCLUSIONS

Key findings and implications for possible clinical utility of biochemical markers are summarized and discussed. Given the paucity of robust biomarkers within the field, and the heterogeneity of the condition, enormous works are needed for development and validation of novel and clinically applicable biomarkers to reduce the impact of this highly prevalent and debilitating condition.

Serological biomarker profiles of rapidly progressive osteoarthritis in tanezumab-treated patients

There is a need for efficacious and safe pain treatments for OA (osteoarthritis). The nerve growth factor (NGF) antibody tanezumab is associated with high efficacy, but when combined with chronic NSAID treatment shows an increased risk of rapidly progressive osteoarthritis (RPOA) in a small group of patients.

AIM

The aim of this study was to phenotype with biochemical biomarkers of bone, cartilage, soft tissue, synovial metabolism OA patients who are at risk of developing RPOA type-2, for both limited and chronic NSAIDs users.

MATERIAL AND METHODS

The dataset consisted of OA patients participating in tanezumab trials who used NSAIDs <90 days (limited NSAID users) or chronic users (NSAIDs ≥90 days) over an average 10 month period. Biomarker data were available for 47 cases (RPOA type-2) and 92 controls. Non-linear and linear multivariable predictive models were developed.

RESULTS

By use of two biomarkers at baseline the receiver operating characteristic (ROC) curve area for RPOA type-2 in limited NSAID users was 71%, [CI] (60-83%). OA subjects with this biomarker phenotype had 8-fold higher confidence interval [CI][(2-33)] relative risk of developing RPOA type-2 as compared to OA patients without this phenotype. The AUC of the model in chronic NSAIDs users based on 5 biomarkers was 78%, [CI](69-88%), with 4-fold [CI (2-6)] relative risk of developing RPOA type-2.

CONCLUSION

In this hypothesis generating and exploratory study, we identified combinations of biomarkers associated with OA patients who develop RPOA type-2, which may be related to the pathology of the RPOA type-2 joint.

IL-37 diminishes proteoglycan loss in human OA cartilage: donor-specific link between IL-37 and MMP-3

OBJECTIVE

A hallmark of osteoarthritis (OA) is degradation of articular cartilage proteoglycans. In isolated human OA chondrocytes, the anti-inflammatory cytokine Interleukin-37 (IL-37) lowers the expression of the proteolytic MMP and ADAMTS enzymes, which mediate this degradation. Therefore, we investigated if IL-37 protects against proteoglycan loss in freshly obtained human OA explants.

MATERIAL AND METHODS

Human OA cartilage explants were incubated with IL-37. Release of sulphated proteoglycans (sGAGs) was measured with the dimethylmethylene-blue assay. Production and degradation of newly synthesized proteoglycans was measured using ³⁵S-sulphate. Proteoglycan and proteolytic enzyme expression were analyzed by qPCR and Western Blot. Proteolytic activity was determined by measuring MMP- and ADAMTS-generated aggrecan neo-epitopes with ELISA and by using MMP-3-, MMP-13- or ADAMTS-5-inhibitors.

RESULTS

Over time, a linear release of sGAGs from OA cartilage was measured. IL-37 reduced this release by 87 μg/ml (24%) 95%CI [21.04-141.4]. IL-37 did not affect ³⁵S-sulphate incorporation or proteoglycan gene expression. In contrast, IL-37 reduced loss of ³⁵S-sulphate labeled GAGs and reduced MMP-3 protein expression, indicating that IL-37 inhibits proteoglycan degradation. Remarkably, we observed two groups of patients; one group in which MMP-3-inhibition lowered sGAG release, and one group in which ADAMTS5-inhibition had this effect. Remarkably, IL-37 was only functional in the group of patients that responded to MMP-3-inhibition.

CONCLUSION

We identified a relationship between IL-37 and reduced sGAG loss in OA cartilage. Most likely, this effect is mediated by inhibition of MMP-3 expression. These results suggest that IL-37 could be applied as therapy in a subgroup of OA patients, in which cartilage degradation is mediated by MMP-3.

A machine learning approach for the identification of new biomarkers for knee osteoarthritis development in overweight and obese women

OBJECTIVE

Knee osteoarthritis (OA) is among the higher contributors to global disability. Despite its high prevalence, currently, there is no cure for this disease. Furthermore, the available diagnostic approaches have large precision errors and low sensitivity. Therefore, there is a need for new biomarkers to correctly identify early knee OA.

METHOD

We have created an analytics pipeline based on machine learning to identify small models (having few variables) that predict the 30-months incidence of knee OA (using multiple clinical and structural OA outcome measures) in overweight middle-aged women without knee OA at baseline. The data included clinical variables, food and pain questionnaires, biochemical markers (BM) and imaging-based information.

RESULTS

All the models showed high performance (AUC > 0.7) while using only a few variables. We identified both the importance of each variable within the models as well its direction. Finally, we compared the performance of two models with the state-of-the-art approaches available in the literature.

CONCLUSIONS

We showed the potential of applying machine learning to generate predictive models for the knee OA incidence. Imaging-based information were found particularly important in the proposed models. Furthermore, our analysis confirmed the relevance of known BM for knee OA. Overall, we propose five highly predictive small models that can be possibly adopted for an early prediction of knee OA.

Sprifermin (rhFGF18) enables proliferation of chondrocytes producing a hyaline cartilage matrix

OBJECTIVE

Fibroblast growth factor (FGF) 18 has been shown to increase cartilage volume when injected intra-articularly in animal models of osteoarthritis (OA) and in patients with knee OA (during clinical development of the recombinant human FGF18, sprifermin). However, the exact nature of this effect is still unknown. In this study, we aimed to investigate the effects of sprifermin at the cellular level.

DESIGN

A combination of different chondrocyte culture systems was used and the effects of sprifermin on proliferation, the phenotype and matrix production were evaluated. The involvement of MAPKs in sprifermin signalling was also studied.

RESULTS

In monolayer, we observed that sprifermin promoted a round cell morphology and stimulated both cellular proliferation and Sox9 expression while strongly decreasing type I collagen expression. In 3D culture, sprifermin increased the number of matrix-producing chondrocytes, improved the type II:I collagen ratio and enabled human OA chondrocytes to produce a hyaline extracellular matrix (ECM). Furthermore, we found that sprifermin displayed a 'hit and run' mode of action, with intermittent exposure required for the compound to fully exert its anabolic effect. Finally, sprifermin appeared to signal through activation of ERK.

CONCLUSIONS

Our results indicate that intermittent exposure to sprifermin leads to expansion of hyaline cartilage-producing chondrocytes. These in vitro findings are consistent with the increased cartilage volume observed in the knees of OA patients after intra-articular injection with sprifermin in clinical studies.

Identification of serological biomarker profiles associated with total joint replacement in osteoarthritis patients

OBJECTIVE

Establish a biomarker panel associated with all-cause total joint replacement (TJR) through identification of patients with osteoarthritis (OA) who do or do not progress to TJR and investigate effects of nonsteroidal anti-inflammatory drugs (NSAIDs).

DESIGN

Serum samples from patients enrolled in phase III trials of tanezumab who experienced TJR (n = 174) or matched patients who did not (n = 321) were analyzed for bone, cartilage, soft tissue, and inflammation markers. Classification and Regression Tree (CART) analysis was used to identify biomarker phenotypes associated with TJR.

RESULTS

At baseline, biomarker combinations for patients who did not use NSAIDs before starting tanezumab and used NSAIDs during tanezumab treatment <90 days ("nonNSAID"), identified 77% (95% confidence interval [CI]: 71-84%) of patients who experienced TJR and 77% (95% CI: 65-86%) who did not over a 6-month study period (on average). These biomarker combinations increased odds of identifying patients to remain free of a TJR by 3.3-fold. In patients who used NSAIDs continuously (during screening and ≥90 days during tanezumab treatment), 64% (95% CI: 54-73%) who had TJR and 75% (95% CI: 68-83%) who did not were identified by biomarker combinations different from nonNSAID patients, with an increase in odds of identifying patients to remain free of a TJR by two-fold.

CONCLUSIONS

Although validation on other cohorts is necessary, biomarkers may assist in identifying patients who will need TJR. The profiles suggest NSAID use increases importance of bone metabolism in TJR pathology.

Disease-modifying treatments for osteoarthritis (DMOADs) of the knee and hip: lessons learned from failures and opportunities for the future

Osteoarthritis (OA) is the biggest unmet medical need among the many musculoskeletal conditions and the most common form of arthritis. It is a major cause of disability and impaired quality of life in the elderly. We review several ambitious but failed attempts to develop joint structure-modifying treatments for OA. Insights gleaned from these attempts suggest that these failures arose from unrealistic hypotheses, sub-optimal selection of patient populations or drug dose, and/or inadequate sensitivity of the trial endpoints. The long list of failures has prompted a paradigm shift in OA drug development with redirection of attention to: (1) consideration of the benefits of localized vs systemic pharmacological agents, as indicated by the increasing number of intra-articularly administered compounds entering clinical development; (2) recognition of OA as a complex disease with multiple phenotypes, that may each require somewhat different approaches for optimizing treatment; and (3) trial enhancements based on guidance regarding biomarkers provided by regulatory agencies, such as the Food and Drug Administration (FDA), that could be harnessed to help turn failures into successes.

Collagen degradation products measured in serum can separate ovarian and breast cancer patients from healthy controls: A preliminary study

BACKGROUND

During cancer the otherwise tightly controlled homeostasis of the extracellular matrix (ECM) is disturbed. The protein composition changes, the ECM stiffens and increased levels of proteases are secreted. The combination of these processes result in release of specific protein fragments (e.g. collagens) to the circulation, which when measured may reflect disease pathogenesis.

OBJECTIVE

To investigate if biomarkers of protease-degraded collagen could differentiate ovarian and breast cancer patients from healthy controls when measured in serum.

METHODS

The levels of markers reflecting MMP-degradation of type I (C1M), type III (C3M) and type IV (C4M, C4M12) collagen were assessed in serum from ovarian cancer patients (n= 10), breast cancer patients (n= 14) and healthy controls (n= 49) using validated ELISAs. The markers were compared using one way ANOVA and AUC was calculated.

RESULTS

All markers were significantly elevated in serum from ovarian cancer patients (p< 0.0001) and breast cancer patients (p< 0.04-0.0001) compared to healthy controls. Furthermore, diagnostically the markers were able to differentiate ovarian (AUROC 90%-93%) and breast cancer patients (AUROC 76%-93%) from healthy controls, with C1M being the strongest differentiator of disease vs.

CONCLUSION

Four serum biomarkers reflecting altered MMP-mediated collagen turnover were able to differentiate ovarian and breast cancer patients from healthy controls.

Quantification of fibronectin as a method to assess ex vivo extracellular matrix remodeling

Altered architecture, composition and quality of the extracellular matrix (ECM) are pathological hallmarks of several inflammatory and fibro-proliferative pathological processes such as osteoarthritis (OA), rheumatoid arthritis (RA), fibrosis and cancer. One of the most important components of the ECM is fibronectin. Fibronectin serves as an adhesion molecule anchoring cells to the underlying basement membrane through direct interaction with integrin receptors. Fibronectin hereby modulates the properties of the ECM and affects cellular processes. Quantification of fibronectin remodeling could therefore be used to assess the changes in the ECM that occur during progression of fibro-proliferative pathologies. Ex vivo models are becoming state-of-the-art tools to study ECM remodeling as the cellular composition and the organization of the ECM are preserved. Ex vivo models may therefore be a valuable tool to study the ECM remodeling that occurs during progression of fibro-proliferative pathologies. The aim of this study was to quantify fibronectin remodeling in ex vivo models of cartilage and cancer. A competitive The enzyme-linked immunosorbent assay (ELISA) against the C-terminus of fibronectin was developed (FBN-C). The assay was evaluated in relation to specificity, technical performance and as a marker for quantification of fibronectin in cartilage and cancer ex vivo models. The ELISA was specific and technically stable. Cleavage of tumor tissue with MMP-2 released significantly higher levels of FBN-C compared to tissue with buffer only and western blot analysis revealed that FBN-C recognizes both full length and degraded fibronectin. When ex vivo cartilage cultures were stimulated with the anabolic factor TGFβ and catabolic factors TNF-α and OSM, significantly higher levels of FBN-C were found in the conditioned media. Lastly, FBN-C was released from a cancer ex vivo model. In conclusion, we were able to quantify fibronectin remodeling in ex vivo models of cartilage and cancer. Quantification of fibronectin remodeling could be a valuable tool to understand ECM remodeling in ex vivo models of fibro-proliferative pathologies.

Osteoarthritis biomarkers derived from cartilage extracellular matrix: Current status and future perspectives

Specific soluble biomarkers can be powerful tools for the diagnosis, prognosis and personalized management of osteoarthritis (OA). Biomarkers are potential indicators of the effect of a drug on cartilage metabolism and provide crucial information about the mechanisms of drug action. In this review, we address key questions concerning the use of biomarkers in OA management: Why do we need soluble biomarkers? What are the most widely investigated biomarkers derived from cartilage extracellular matrix? What are the most common pitfalls in interpreting soluble biomarker measurements? What are the perspectives and future research directions in this field? We review current evidence to propose that cartilage-derived soluble biomarkers are complementary "drug development tools" that can be applied during drug development from preclinical research to clinical evaluation. In the future, such biomarkers could be surrogate markers of clinical and/or imaging outcomes. Successful standardization and implementation of automated biomarker assays will facilitate their use in companion diagnostics in the context of personalized medicine for enhanced management of OA.

Osteoarthritis year in review 2015: soluble biomarkers and the BIPED criteria

OBJECTIVE

To review and summarize biomarker data published from April 2014 to May 2015 to provide insight to the ongoing work in the field of osteoarthritis (OA). Furthermore, to summarize the BIPED criteria and set it in context of the medical needs of 2015.

METHODS

PubMed was used as searching machine: Time period 2014/04/01-2015/05/01, MeSH term [Biomarker] AND [Osteoarthritis], Language; English, Full text available. Reviews were excluded. Only papers describing protein based biomarkers measured in human body fluids from OA patients were included.

RESULTS

Biomarkers of joint tissue turnover, cytokines, chemokines and peptide arrays were measured in different cohorts and studies. Amongst those were previously tested biomarkers such as osteocalcin, Carboxy-terminal cross-linked fragment of type II collagen (CTX-II) and cartilage oligomeric matrix protein (COMP). A majority of the biomarker were classified as I, B or B biomarkers according to the BIPED criteria. Work is continuing on testing biomarkers in OA. There is still a huge, unmet medical need to identify, test, validate and qualify novel and well-known biomarkers. A pre-requisite for this is better characterization and classification of biomarkers to their needs, which may not be reached before higher understanding of OA phenotypes has been gained. In addition, we provide some references to some recent guidelines from Food and Drug Administration (FDA) and European Medicines Agency (EMA) on qualification and usage of biomarkers for drug development and personalized medicine, which may provide value to the field.

Inflammation (or synovitis)-driven osteoarthritis: an opportunity for personalizing prognosis and treatment?

The disabling and painful disease osteoarthritis (OA) is the most common form of arthritis. Strong evidence suggests that a subpopulation of OA patients has a form of OA driven by inflammation. Consequently, understanding when inflammation is the driver of disease progression and which OA patients might benefit from anti-inflammatory treatment is a topic of intense research in the OA field. We have reviewed the current literature on OA, with an emphasis on inflammation in OA, biochemical markers of structural damage, and anti-inflammatory treatments for OA. The literature suggests that the OA patient population is diverse, consisting of several subpopulations, including one associated with inflammation. This inflammatory subpopulation may be identified by a combination of novel serological inflammatory biomarkers. Preliminary evidence from small clinical studies suggests that this subpopulation may benefit from anti-inflammatory treatment currently reserved for other inflammatory arthritides.

OA phenotypes, rather than disease stage, drive structural progression--identification of structural progressors from 2 phase III randomized clinical studies with symptomatic knee OA

BACKGROUND/PURPOSE

The aim of this study was to identify key characteristics of disease progression through investigation of the association of radiographic progression over two years with baseline Joint Space Width (JSW), Kellgren-Lawrence (KL) grade, Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain, Joint Space Narrowing (JSN), and BMI.

METHODS

Data from 2206 subjects (4390 knees) were combined for this post-hoc analysis of two randomized, double-blind, multi-center, placebo-controlled phase III trials (NCT00486434 and NCT00704847) that evaluated the efficacy and safety of 2-years treatment with oral salmon calcitonin of subjects with painful knee osteoarthritis (OA).

RESULTS

There was a clear positive and significant correlation between KL grade and WOMAC pain and total WOMAC, albeit the variance in pain measures was from min-to-max for all KL categories, emphasizing the heterogeneity of this patient population and pain perception. 32% of target knees did not progress, and only 51% had changes over minimum significant change (MSC). BMI, KL-Score and WOMAC pain was diagnostic, but only KL-score and pain had prognostic value, albeit pain in a non-linear manner.

CONCLUSION

These data clearly describe significant associations between KL grade, JSW, pain and BMI in patients with symptomatic knee OA. KL grade, BMI and WOMAC pain were diagnostically associated with OA based on JSW but only KL-score and pain in a non-linier fashion was prognostic. 50% of patients did not progress more than MSC, highlighting the importance for identification of structural progressors and the phenotypes associated with these. These results suggest that disease phenotypes, rather than disease status, are responsible for disease progression.

Association between biochemical cartilage markers and clinical symptoms in patients with hip osteoarthritis: cohort study with 2-year follow-up

OBJECTIVES

To assess associations between uCTX-II or uCIIM and severity of hip pain in patients with mild-moderate hip osteoarthritis (OA) over a 2-year period, and establish whether the level of these biomarkers at baseline could estimate a specific trajectory of hip pain.

DESIGN

A cohort study with a 2-year follow-up and 6-monthly measurements of urinary biomarkers (uCTX-II and uCIIM) and symptom severity. Patients were recruited from general practices. The primary outcome was hip pain, measured with the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) subscale and the Visual Analog Scale (VAS). Associations between hip pain and biomarkers were assessed using linear mixed-model analysis for repeated measurements. Five previously identified pain trajectories were used as outcome to investigate whether the level of biomarkers at baseline could estimate membership in one of the trajectories using multinomial regression analysis.

RESULTS

LoguCTX-II and loguCIIM were not associated with WOMAC pain or VAS pain during the 2-year follow-up. Patients in the highly progressive pain trajectory and the moderate pain trajectory were more likely to have a higher loguCTX-II at baseline (OR 6.7; 95% CI 1.6-28.2 and OR 4.8; 95% CI 1.0-22.8, respectively) than patients in the mild pain trajectory.

CONCLUSION

This study shows that in patients with mild-moderate hip OA the urinary biochemical markers uCTX-II and uCIIM are not cross-sectionally associated with hip pain during the 2-year follow-up. Because the uCTX-II level estimated a progressive or moderate hip pain trajectory, this correlation needs to be confirmed in additional patients with hip OA.

Large scale meta-analysis of urinary C-terminal telopeptide, serum cartilage oligomeric protein and matrix metalloprotease degraded type II collagen and their role in prevalence, incidence and progression of osteoarthritis

OBJECTIVE

To evaluate the role of three cartilage-derived biomarkers on osteoarthritis (OA): urinary C-terminal telopeptide (uCTX-II), serum cartilage oligomeric protein (sCOMP), and serum MMP degraded type II collagen (sC2M).

SUBJECTS AND METHODS

Samples from 3582 individuals from the Rotterdam Study, the Genetics osteoArthritis and Progression (GARP), the Chingford Study and the TwinsUK cohort were assayed using enzyme-linked immune sorbent assays. Log10 of concentration levels were correlated with risk of hip, hand and knee OA, hip and knee OA severity and incidence, and progression of knee OA, adjusting for age, gender and body mass index (BMI). Results were meta-analysed to assess overall significance.

RESULTS

After adjusting for covariates, sCOMP was associated with knee OA and hip and knee OA incidence. Furthermore, sC2M was associated with knee OA incidence and progression. After adjustment for multiple tests (Bonferroni P < 0.002) only the association between sCOMP and knee OA remained significant (odds ratio (OR) = 3.26 (95%CI 1.63-10.1) P = 0.0008 for each standard deviation (SD) increase in biomarker levels). Levels of uCTX-II were significantly associated with risk of hand, hip and knee OA, progression and incidence of knee OA. A receiver operating characteristics (ROC) analysis showed a consistent improvement in prediction of knee OA progression from an average area under the curve (AUC) is 0.646 for age, sex and BMI alone to an AUC = 0.668 including uCTX-II for prediction.

CONCLUSIONS

uCTX-II is the most informative biochemical marker for prediction of OA. Both sCOMP and C2M showed some association with OA, thus indicating that they are descriptive of disease activity.

Osteoarthritis--a case for personalized health care?

For both economic and ethical reasons, identification of the optimal treatment for each individual patient is a pressing concern, not only for the patients and their physician, but also health care payers and the pharmaceutical industry. In the field of osteoarthritis (OA) this is of particular relevance, due to the heterogeneity of the disease and the very large number of affected individuals. There is a need to pair the right patients with the right therapeutic modes of action. At present, the clinical trial failures in OA may be a consequence of both bona fide treatment failures and trial failures due to clinical design deficiencies. Tools are needed for characterization and segregation of patients with OA. Key lessons may be learned from advances with another form of arthritis, namely rheumatoid arthritis (RA). Personalized health care (PHC) may be more advantageous for a number of specific indications which are characterized by costly therapy, low response rates and significant problems associated with trial and error prescription, including the risk of serious side effects. We discuss the use of diagnostic practices guiding RA treatment, which may serve as a source of key insights for diagnostic practices in OA. We discuss the emerging concept of PHC, and outline the opportunities and current successes and failures across the RA field, as the OA field collects further data to support the hypothesis. We attempt to outline a possible path forward to assist patients, physicians, payers and the pharmaceutical industry in assuring the 'right' patients are treated with the 'right drug' in OA. Finally we highlight methods for possible segregation of OA patients that would allow identification of patient subtypes, such as OA driven by inflammation that may be ideally suited for PHC and for targeted therapies.

Identification and characterisation of osteoarthritis patients with inflammation derived tissue turnover

OBJECTIVES

Osteoarthritis (OA) is a degenerative disease with a subset of patients experiencing joint inflammation, but C-reactive protein (CRP) has shown limited use in OA as a diagnostic marker. The aim was to identify subpopulations of patients with high or low levels of acute (high sensitive CRP (hsCRP)) and/or matrix metalloproteinase (MMP) derived inflammation (CRPM) and investigate the subpopulations' association with biomarkers of collagen degradation and Kellgren-Lawrence (KL) score.

METHODS

hsCRP, CRPM and MMP-degraded type I, II and III collagen (type I collagen degraded by MMP (C1M), type II collagen degraded by MMP (C2M) and type III collagen degraded by MMP (C3M)) were quantified by enzyme linked immunosorbent assays (ELISA) in serum of 342 patients with symptomatic knee OA of which 60 underwent total knee replacement (TKR). KL was obtained. Patients were divided into quartiles by hsCRP and CRPM levels, where Q1 and Q4 were low or high in both. The biomarker levels of healthy adults provided in the ELISA kits were used as reference level.

RESULTS

hsCRP was elevated in TKR (5.9(3.6-8.2 95% confidence interval (CI)) μg/mL) compared to reference level (3 μg/mL), while CRPM was highly elevated with OA independent of KL (10-14 ng/mL) compared to reference level (5 ng/mL). Q4 had higher KL than Q1 (P < 0.001), Q2 (P = 0.017) and Q3 (P < 0.001). C1M, C2M and C3M were lowest in Q1. C1M was elevated in Q3 compared to Q2 (P < 0.001), whereas C3M was lower (P = 0.019).

CONCLUSION

A bigger proportion of patients were elevated in CRPM compared to hsCRP, indicating MMP-derived inflammation as a component of OA. Moreover, the levels of MMP-degraded collagens differed between the subgroups segregated by inflammation, indicating distinctively different subpopulation selected by inflammation.

The coupling of bone and cartilage turnover in osteoarthritis: opportunities for bone antiresorptives and anabolics as potential treatments?

Osteoarthritis (OA) is the most common form of arthritic disease, and a major cause of disability and impaired quality of life in the elderly. OA is a complex disease of the entire joint, affecting bone, cartilage and synovium that thereby presents multiple targets for treatment. This manuscript will summarise emerging observations from cell biology, preclinical and preliminary clinical trials that elucidate interactions between the bone and cartilage components in particular. Bone and cartilage health are tightly associated. Ample evidence has been found for bone changes during progression of OA including, but not limited to, increased turnover in the subchondral bone, undermineralisation of the trabecular structure, osteophyte formation, bone marrow lesions and sclerosis of the subchondral plate. Meanwhile, a range of investigations has shown positive effects on cartilage health when bone resorption is suppressed, or deterioration of the cartilage when resorption is increased. Known bone therapies, namely oestrogens, selective oestrogen receptor modifiers (SERMs), bisphosphonates, strontium ranelate, calcitonin and parathyroid hormone, might prove useful for treating two critical tissue components of the OA joint, the bone and the cartilage. An optimal treatment for OA likely targets at least these two tissue components. The patient subgroups for whom these therapies are most appropriate have yet to be fully defined but would likely include, at a minimum, those with high bone turnover.