POS0471 INDUCED ANTIBODIES DIRECTED TO THE ANGIOTENSIN RECEPTOR TYPE 1 PROVOKE SKIN AND LUNG INFLAMMATION AND DERMAL FIBROSIS AND ACT SPECIES OVERARCHING

Background

Antibodies directed to the angiotensin receptor type 1 (AT1R) were found to be increased in patients with SSc ad they predict mortality and SSc complications (1, 2). In vitro studies suggested an involvement in the pathogenesis of systemic sclerosis (SSc).

Objectives

Here, we aim to determine the contribution and functions of AT1R autoantibodies (Abs) in vivo and in vitro as well as their capacity to recognize AT1R from different species.

Methods

C57BL/6J mice were immunized with membrane-embedded human AT1R or empty membrane as control. Phenotypic properties of various organs were examined by immunohistochemistry, immunofluorescence, and TUNEL apoptosis assay. A monoclonal (m)AT1R Ab was generated based upon this mouse model by hybridoma technology and transferred into C57BL/6J mice. Mice deficient for CD4+ and CD8+ T cells, B cells and AT1Ra/b served as controls. In vitro, Abs responses towards AT1R were measured using rat cardiomyocytes, human epithelial cells, AT1R-transfected HEK293 cells and primary human monocytes.

Results

AT1R-immunized mice developed perivascular skin and lung inflammation, lymphocytic alveolitis, weak endothelial apoptosis and skin fibrosis, not present in controls or mice deficient for CD4+ T and B cells. The contribution of AT1R Abs to skin manifestations and interstitial lung disease was demonstrated by application of a mAT1R Ab, which induced skin and lung inflammation, not observed in the AT1Ra/b knockout mice. IgG from immunized mice containing AT1R Abs and/or the mAT1R Ab activated rat cardiomyocytes and human monocytes. Treatment of AT1R-transfected HEK293 cells with the mAT1R Ab enhanced AT1R signaling in the presence of the endogenous agonist Angiotensin II.

Conclusion

Our immunization strategy successfully induced AT1R Abs, contributing to inflammation and most likely to fibrosis via activation of AT1R. Therefore, AT1R Abs are valuable targets for future therapies in SSc and possibly other AT1R Ab-related diseases.

References

[1]Riemekasten, G. et al. Involvement of functional autoantibodies against vascular receptors in systemic sclerosis. Ann. Rheum. Dis. 70, 530–536 (2011).

[2]Becker, M. O. et al. Vascular receptor autoantibodies in pulmonary arterial hypertension associated with systemic sclerosis. Am. J. Respir. Crit. Care Med. 190, 808–817 (2014).

Figure 1.

AT1R immunization and induction of AT1R Abs in C57BL/6J mice induced lymphocytic alveolitis in bronchoalveolar fluid (A), interstitial lung disease (B) with increased inflammatory score (C)

Figure 2.

AT1R immunization and induction of AT1R Abs in C57BL/6J mice induced skin fibroses (A) as determined by collagen content (B) and skin thickness (C).

Acknowledgements

This manuscript was founded by the German Research Council RI1056/11-1-3 and the Excellence Cluster Precision Medicine in Inflammation and by the BMBF-founded Mesinflame project.

Disclosure of Interests

None declared.

POS0872 SERUM LEVEL OF SOLUBLE INTERLEUKIN-2 RECEPTOR IS LINKED TO BETA2-MICROGLOBULINE, NT-PRO BNP AND HIGH-SENSITIVITY TROPONIN T AND MAY HELP TO IDENTIFY PATIENTS WITH EARLY CLINICAL PROGRESS IN SSc

Background

Systemic sclerosis (SSc) is characterized by chronic inflammation that leads to damage of the vascular endothelium and excessive collagen deposition in several target organs (1). The interaction of interleukin 2 (IL-2) with the corresponding receptor (IL-2R) is involved in the regulation of autoimmune processes (2). The shedding product of the IL-2R alpha chain, soluble IL-2 receptor (sIL-2R, CD25), is able to either reduce or enhance immune responses (2). Previously, elevated serum levels of sIL-2R were found in the bronchoalveolar lavage of SSc patients with interstitial lung disease (SSc-ILD) as well as serologically in patients with early SSc, and thus suggested to be a biomarker for clinical development of SSc (3,4).

Objectives

To examine concentrations of sIL-2 in patients with SSc and analyse their association with clinical and serological parameters.

Methods

To determine if serological levels of sIL-2R serve as predictor of clinical complications in SSc, sera were analysed [limited cutaneous SSc (lcSSc) n=160; diffuse cutaneous SSc (dSSc), n=137] using a sandwich ELISA. Clinical data (pulmonary fibrosis, PAH, mRSS, therapy) and serological markers (hs-CRP, NT-pro BNP, neutrophil counts, creatinine, hs-troponin T, creatinine kinase, beta2-microglobuline) were assessed at the time of serum sampling and up to 48 months after baseline. Clinical progress was defined by the need to change therapies.

Results

Patients with dSSc presented elevated levels of sIL-2R compared to SSc (dSSc: 673±428 U/ml vs. 646±473 U/ml, p=0.0001). In SSc general, sIL-2R levels correlated with beta2-microglobuline (r=0.6161, p<0.0001, ROC-AUC:0.8428), hs-CRP (r=0.4091, p<0.0001, ROC-AUC:0.7110), NT-proBNP (r=0.2610, p<0.0001, ROC-AUC:0.6793), neutrophil count (r=0.2749, p<0.0001) and hs-troponin T (r=0.4548, p<0.0001, ROC-AUC:0.8729). Further, sIL-2R levels discriminated normal from pathological levels of hs-troponin T (sensitivity 80.0%, specificity 80.1%). Using Log-rank test and Mantel-Cox proportional hazard models, we found that sIL-2R levels above 745.5 U/ml predicted early clinical progress in SSc (HR: 3.45, p=0.0070, Figure 1) within 12 months.

Figure 1.

Kaplan-Meier survival analysis for the complete group of patients with SSc. Soluble Il-2R levels above 745U/ml were associated with early progress in SSc.

Conclusion

In SSc, serum levels of sIL-2R could be of diagnostic value by identifying clinical progress. Its role in pathophysiology, especially with regard to disease manifestations such as cardiac involvement needs to be investigated in more detail.

References

[1]Blagojevic J et al. Use of vasoactive/vasodilating drugs for systemic sclerosis (SSc)-related digital ulcers (DUs) in expert tertiary centres: results from the analysis of the observational real.life DeSScipher study. Clin Rheumatol. 2020Jan;39(1):27-36.

[2]Damoiseaux J The Il-2-Il-2 receptor pathway in health and disease: The role of the soluble IL-2 receptor. Clin Immunol 2020;Sep;218:108515

[3]Martinez JA et al. Elevation of soluble interleukin-2 receptor levels in thebronchoalveolar lavage from patients with systemic sclerosis. Rheumatol Int. 2001 Nov;21(3):122-6

[4]Valentini G et al. Early systemic sclerosis: short-term disease evolution and factors predicting the development of new manifestations of organ involvement. Arthritis Res Ther 2012 Aug17;14(4):R188

Disclosure of Interests

None declared

Autoantibodies targeting GPCRs and RAS-related molecules associate with COVID-19 severity

COVID-19 shares the feature of autoantibody production with systemic autoimmune diseases. In order to understand the role of these immune globulins in the pathogenesis of the disease, it is important to explore the autoantibody spectra. Here we show, by a cross-sectional study of 246 individuals, that autoantibodies targeting G protein-coupled receptors (GPCR) and RAS-related molecules associate with the clinical severity of COVID-19. Patients with moderate and severe disease are characterized by higher autoantibody levels than healthy controls and those with mild COVID-19 disease. Among the anti-GPCR autoantibodies, machine learning classification identifies the chemokine receptor CXCR3 and the RAS-related molecule AGTR1 as targets for antibodies with the strongest association to disease severity. Besides antibody levels, autoantibody network signatures are also changing in patients with intermediate or high disease severity. Although our current and previous studies identify anti-GPCR antibodies as natural components of human biology, their production is deregulated in COVID-19 and their level and pattern alterations might predict COVID-19 disease severity.

Clinical effects of glabellar botulinum toxin injections on borderline personality disorder: A randomized controlled trial

BACKGROUND

Inhibition of frowning via injections of botulinum toxin A (BTX) into the glabellar region has shown beneficial effects in the treatment of major depression. Preliminary research suggests that improvements in the affective domain are not depression-specific, but may also translate to other psychiatric disorders.

AIM

This 16-week, single-blind, two-center randomized controlled trial investigated the influence of BTX on clinical symptoms of borderline personality disorder (BPD).

METHODS

Fifty-four patients with BPD were randomly assigned to treatment with BTX (n = 27) or a minimal acupuncture (ACU) control condition (n = 27). Clinical outcomes were followed at 2, 4, 6, 8, 12, and 16 weeks. Primary endpoint was the relative score change on the Zanarini Rating Scale for Borderline Personality Disorder (ZAN-BPD) 8 weeks after baseline relative to the control group and adjusted for treatment center. Secondary and additional outcome variables were self-rated borderline symptoms, comorbid symptoms of depression, psychological distress, and clinical global impression.

RESULTS

Participants showed significant improvements at the primary efficacy endpoint in both treatment groups (BTX: M = -0.39, SD = 0.39; ACU: M = -0.35, SD = 0.42), but no superior effect of the BTX condition in comparison with the control intervention was found-F(1,5323) = 0.017, p = 0.68). None of the secondary or additional outcomes yielded significant group differences. Side effects were mild and included headache, transient skin or muscle irritations, and dizziness.

CONCLUSION

Evidence regarding the efficacy of BTX for BDP remains limited, and the design of adequate control conditions presents an opportunity for further research.ClinicalTrials.gov registry: Botulinum Toxin A for Emotional Stabilization in Borderline Personality Disorder (BPD), NCT02728778, https://clinicaltrials.gov/ct2/show/NCT02728778.

[Update on etiopathogenesis of small vessel vasculitis]

Small vessel vasculitis is characterized by a necrotizing inflammation of the vessel wall predominantly with involvement of small intraparenchymal arteries, arterioles, capillaries and venules. Medium-sized and occasionally large vessels can also be involved. Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (granulomatosis with polyangiitis, microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis) are differentiated from immune complex vasculitides based on immunopathological and serological aspects. Immune complex vasculitides include IgA vasculitis, cryoglobulinemic vasculitis, hypocomplementemic urticarial vasculitis (anti-C1q vasculitis) and anti-glomerular basement membrane disease. Epidemiological and next-generation sequencing-based studies have significantly contributed to the identification of predisposing environmental factors and genetic risk factors in recent years. Under specific conditions ANCA and immune complexes can induce premature intravascular activation of neutrophilic granulocytes with degranulation and release of enzymes and reactive oxygen species, which leads to vascular damage. In granulomatosis with polyangiitis and eosinophilic granulomatosis with polyangiitis various factors, such as barrier dysfunction and dysbiosis of the microbiome contribute to extravascular granuloma formation predominantly affecting the respiratory tract.

OS06.5A Fluorescence image-guided resection of intracranial meningioma: an experimental in vivo study on nude mice

BACKGROUND

The use of photodynamic agents in malignant cranial tumor surgery is quite common. For example five-aminolevulinic acid (5-ALA)-induced porphyrins in malignant gliomas are potent photosensitizers. Until today there is no comparable selective fluorescent substance available for meningiomas. Nevertheless, there is a demand for intraoperative fluorescent identification of e.g. invasive skull base meningiomas to increase radicality. This study was established to investigate fluorescent image-guided resection with somatostatin receptor labelled fluorescence dye for intracranial meningioma in the nude mice.

MATERIAL AND METHODS

Primary meningioma cell culture samples were stereotactically implanted subdural into 20 nude mice. 90 days after inoculation of the cells, a cranial MRI with contrast agent revealed tumor growth. After detection of tumor mass in MRI, FAM-TOC5,6-Carboxyfluoresceine-Tyr3-Octreotide was injected intravenously and tumor mass was hereafter resected under visualization via fluorescence microscope and endoscope. After attempted total resection, animal were sacrificed brain slices were obtained and histologically analysed to verify the resection extent.

RESULTS

In 18 mice tumor growth was detected in MRI after 90 days of inoculation. The tumor mass could be clearly identified with fluorescence microscope and endoscope after injecting FAM-TOC5,6-Carboxyfluoresceine-Tyr3-Octreotide. The tumor margins could be better visualized. After fluorescence-guided resection no remaining tumor could be identified in histological analysis.

CONCLUSION

This study describes for the first time the use of FAM-TOC5,6-Carboxyfluoresceine-Tyr3-Octreotide and demonstrates its value of fluorescent identification of meningioma cells in vivo. Furthermore, the authors established a new experimental animal model for fluorescence meningioma surgery.

MiR-205-driven downregulation of cholesterol biosynthesis through SQLE-inhibition identifies therapeutic vulnerability in aggressive prostate cancer

Prostate cancer (PCa) shows strong dependence on the androgen receptor (AR) pathway. Here, we show that squalene epoxidase (SQLE), an enzyme of the cholesterol biosynthesis pathway, is overexpressed in advanced PCa and its expression correlates with poor survival. SQLE expression is controlled by micro-RNA 205 (miR-205), which is significantly downregulated in advanced PCa. Restoration of miR-205 expression or competitive inhibition of SQLE led to inhibition of de novo cholesterol biosynthesis. Furthermore, SQLE was essential for proliferation of AR-positive PCa cell lines, including abiraterone or enzalutamide resistant derivatives, and blocked transactivation of the AR pathway. Inhibition of SQLE with the FDA approved antifungal drug terbinafine also efficiently blocked orthotopic tumour growth in mice. Finally, terbinafine reduced levels of prostate specific antigen (PSA) in three out of four late-stage PCa patients. These results highlight SQLE as a therapeutic target for the treatment of advanced PCa.

Investigation of the impact of magnesium versus titanium implants on protein composition in osteoblast by label free quantification

Metallic implant biomaterials predominate in orthopaedic surgery. Compared to titanium-based permanent implants, magnesium-based ones offer new possibilities as they possess mechanical properties closer to the ones of bones and they are biodegradable. Furthermore, magnesium is more and more considered to be "bioactive" i.e., able to elicit a specific tissue response or to strengthen the intimate contact between the implant and the osseous tissue. Indeed, several studies demonstrated the overall beneficial effect of magnesium-based materials on bone tissue (in vivo and in vitro). Here, the direct effects of titanium and magnesium on osteoblasts were measured on proteomes levels in order to highlight metal-specific and relevant proteins. Out of 2100 identified proteins, only 10 and 81 differentially regulated proteins, compare to the control, were isolated for titanium and magnesium samples, respectively. Selected ones according to their relationship to bone tissue were further discussed. Most of them were involved in extracellular matrix maturation and remodelling (two having a negative effect on mineralisation). A fine-tuned balanced between osteoblast maturation, differentiation and viability was observed.

P–451 Improving neovascularization and follicle viability in cryopreserved bovine ovarian tissue transplants

Study question

Does cryopreservation and transplantation of bovine ovarian medulla-containing cortex tissue improve the viability and vascularization of the graft? Summary answer: Transplantation of bovine ovarian cortex containing medulla has a positive effect on follicular viability and neovascularization of the graft compared to cortex transplantation alone.

What is known already

For female fertility protection, cryopreservation and retransplantation of ovarian tissue is a widely used method. During cryopreservation, ovarian tissue is exposed to mechanical and hypoxic stress resulting in follicular loss. Moreover, after retransplantation tissue vitality and follicle survival is limited due to ischemia. As follicular viability is of major importance for fertility and hormonal activity, the main focus is on improving vitality and viability of the grafts. In current protocols, ovarian medulla is discarded and merely cortex tissue is preserved. However, medulla tissue predominantly contains blood vessels, thereby obtaining high potential for revascularization processes and thereby supporting tissue vitality.

Study design, size, duration

This experimental laboratory work was performed during a period of ten months. The rapidly vascularized chorioallantoic-membrane (CAM) of fertilized chicken eggs was used as model system to investigate neovascularization, follicle survival and tissue vitality of different bovine ovarian grafts. In four independent experimental rows four different tissue types (isolated cortex, thick medulla-containing cortex (8 x 10 x 3 mm), thin medulla-containing cortex (5 x 10 x 3 mm) and sole medulla tissue were compared.

Participants/materials, setting, methods

Out of four bovine ovaries preserved from the slaughterhouse, in total 117 samples of the four different tissue types were primed and cryopreserved by the common slow-freezing protocol. After thawing, grafts were transplanted on separate CAMs at day four of fertilized eggs. After four days of incubation, blood vessels growing towards the grafts were counted. Subsequently, grafts were harvested, digested with collagenase and stained with Neutral Red® to determine the total amount of vital follicles.

Main results and the role of chance

To investigate the neovascularization, all graft-supplying blood vessels were determined and distinguished between small and thick vessels. Compared to sole cortex, there were more small vessels in the medulla-containing grafts (9,72 vs. 8,65). Especially thin medulla- containing cortex pieces exhibited the highest number of small vessels (9,90). Also in isolated medulla tissue an increased amount of small vessels was observed (9,79). However, the average number of big vessels was not significantly different in all four test groups (Cortex: 2,12; thin medulla-containing cortex: 1,69; thick medulla-containing cortex: 1,5; medulla: 2). The total number of all vessels differed from 10,76 (sole cortex) to 11,75 (medulla-containing grafts), indicating a support of neoangiogenesis by medulla tissue. To further examine whether medulla tissue also alters the amount of vital follicles, Neutral Red® stained vital follicles were determined in all different sample groups. Indeed, in medulla-containing cortex samples was an augmented average number of vital follicles (342,4) compared to sole cortex tissue (256,11). Most vital follicles were detectable in the thick medulla-containing cortex tissue (346,61), closely followed by the thin medulla-containing cortex grafts (338,19). As expected, there was just a rare amount of vital follicles in sole medulla grafts (8,13).

Limitations, reasons for caution

As the ovarian reserve in cattle is very individual, the prepared ovaries are different in their follicle amount. These individual differences may influence the number of counted follicles. Furthermore, the CAM model is only a short term experimental approach to investigate neovascularization and follicle survival.

Wider implications of the findings: According to our results, transplantation of human medulla-containing cortex appears promising. Keeping medulla tissue on the graft seems to improve both follicle viability and revascularization. Our findings need to be proven with human tissue, but might change the preparation of human ovarian tissue for fertility preservation in future.

Trial registration number

Not applicable

Transfer of PBMC From SSc Patients Induces Autoantibodies and Systemic Inflammation in Rag2-/-/IL2rg-/- Mice

Objective

The contribution of sustained autologous autoantibody production by B cells to the pathogenesis of systemic sclerosis (SSc) and granulomatosis with polyangiitis (GPA) is not fully understood. To investigate this, a humanized mouse model was generated by transferring patient-derived peripheral blood mononuclear cells (PBMC) into immunocompromised mice.

Methods

PBMC derived from patients with SSc and GPA as well as healthy controls (HD) were isolated, characterized by flow cytometry, and infused into Rag2^-/-/IL2rg^-/- mice. In addition, PBMC from SSc patients treated with rituximab were transferred into mice. Twelve weeks later, human autoantibodies were determined in blood of the recipient mice and affected tissues were analyzed for pathological changes by histology and immunohistochemistry.

Results

Mice engrafted with PBMC derived from SSc patients developed autoantibodies such as antinuclear antibodies (ANA) mimicking the pattern of the respective donors. Moreover, cellular infiltrates dominated by B cells were observed in lung, kidney and muscles of the recipient mice. By contrast, PBMC derived from HD or GPA patients survived in recipient mice after transfer, but neither human autoantibodies nor inflammatory infiltrates in tissues were detected. Furthermore, these pathological changes were absent in mice transferred with PBMC from rituximab-treated SSc patients.

Conclusion

This humanized mouse model is indicative for cross-reactivity of human lymphocytes to murine autoantigens and argues for a pivotal role of B cells as well as of sustained autoimmunity in the pathogenesis of SSc. It provides a powerful tool to study interstitial lung disease and so far, under-recognized disease manifestations such as myositis and interstitial nephritis.

Immunoglobulin G of systemic sclerosis patients programs a pro-inflammatory and profibrotic phenotype in monocyte-like THP-1 cells

OBJECTIVES

Functional IgG autoantibodies against diverse G protein-coupled receptors, i.e. antibodies with agonistic or antagonistic activity at these receptors, are abundant in human serum. Their levels are altered in patients with SSc, and autoantibodies against angiotensin II receptor 1 (ATR1) and endothelin receptor A (ETA) have been suggested to drive SSc by inducing the chemokines CXCL8 and CCL18 in the blood. The objective of our study is to profile the effect of IgG in SSc (SSc-IgG) on the production of soluble mediators in monocytic cells.

METHODS

Monocyte-like THP-1 cells were stimulated with SSc-IgG and their secretome was analysed. Furthermore, the significance of major pro-inflammatory pathways for the induction of CXCL8 and CCL18 in response to SSc-IgG was assessed by a pharmacological approach.

RESULTS

Stimulation with SSc-IgG significantly alters the secretome of THP-1 cells towards a general pro-inflammatory and profibrotic phenotype, which includes an increase of CCL18 and CXCL8. The consequent expression profiles vary depending on the individual donor of the SSc-IgG. CCL18 and CXCL8 expression is thus regulated differentially, with AP-1 driving the induction of both CCL18 and CXCL8 and the TAK/IKK-β/NF-κB pathway and ERK1/2 driving that of CXCL8.

CONCLUSIONS

Our results suggest that SSc-IgG contributes to the generation of the pro-inflammatory/profibrotic tissue milieu characteristic of SSc by its induction of a respective phenotype in monocytes. Furthermore, our results highlight AP-1 as a critical regulator of gene transcription of CCL18 in monocytic cells and as a promising pharmacological therapeutic target for the treatment of SSc.

Granulomatous Inflammation in ANCA-Associated Vasculitis

ANCA-associated vasculitis (AAV) comprises granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). While systemic vasculitis is a hallmark of all AAV, GPA is characterized by extravascular granulomatous inflammation, preferentially affecting the respiratory tract. The mechanisms underlying the emergence of neutrophilic microabscesses; the appearance of multinucleated giant cells; and subsequent granuloma formation, finally leading to scarred or destroyed tissue in GPA, are still incompletely understood. This review summarizes findings describing the presence and function of molecules and cells contributing to granulomatous inflammation in the respiratory tract and to renal inflammation observed in GPA. In addition, factors affecting or promoting the development of granulomatous inflammation such as microbial infections, the nasal microbiome, and the release of damage-associated molecular patterns (DAMP) are discussed. Further, on the basis of numerous results, we argue that, in situ, various ways of exposure linked with a high number of infiltrating proteinase 3 (PR3)- and myeloperoxidase (MPO)-expressing leukocytes lower the threshold for the presentation of an altered PR3 and possibly also of MPO, provoking the local development of ANCA autoimmune responses, aided by the formation of ectopic lymphoid structures. Although extravascular granulomatous inflammation is unique to GPA, similar molecular and cellular patterns can be found in both the respiratory tract and kidney tissue of GPA and MPA patients; for example, the antimicrobial peptide LL37, CD163⁺ macrophages, or regulatory T cells. Therefore, we postulate that granulomatous inflammation in GPA or PR3-AAV is intertwined with autoimmune and destructive mechanisms also seen at other sites.

OP0244 28 NEW AUTOANTIBODIES AGAINST GPCR, GROWTH FACTORS AND GROWTH FACTOR RECEPTORS ARE ASSOCIATED WITH DISEASE MANIFESTATIONS IN SYSTEMIC SCLEROSIS

Background:

The morbidity and mortality of systemic sclerosis (SSc) are largely determined by vascular and fibrotic pathologies. Levels of autoantibodies (ab) against G protein-coupled receptors (GPCR), growth factors (GF) and growth factor receptors (GFR) are altered in SSc compared to healthy controls (HC) 1. Thus, higher angiotensin II receptor type 1 - (AT1R) and endothelin receptor type A - (ETAR) ab levels are associated with severe disease and SSc-related mortality 2. CXC motiv chemokine receptor 3 - (CXCR3) and 4 - (CXCR4) ab have predictive value for deterioration of pulmonary fibrosis (PF) 3.

Objectives:

We used statistical methods to identify associations between disease manifestations and 28 new ab directed against GPCR, GF and GFR in SSc.

Methods:

Ab against the following targets were measured in sera from SSc patients (n = 177) and HC (n = 88): Adrenoceptors alpha-1 (ADRA1), alpha-2 (ADRA2), beta-1 (ADRB1), beta-2 (ADRB2); muscarinoceptors 1-5 (M1R - M5R); AT1R, ETAR, endothelin B receptor (ETBR); CXCR3, CXCR4; complement receptors 3a (C3aR) and 5a (C5aR); protease-activated receptors 1 (PAR1) and 2 (PAR2); vascular endothelial growth factor A (VEGFA) and its receptors 1 (VEGFR1) and 2 (VEGFR2), epithelial growth factor (EGF)/ - receptor (EGFR); hepatocyte growth factor (HGF)/ - receptor (HGFR), platelet-derived growth factor-AA (PDGFAA), placental growth factor (PlGF).

The organ involvement (PF, cardiac involvement, PAH, gastrointestinal tract) and quantitative markers (modified Rodnan skin score, SSc activity score, pulmonary function, cardiac enzymes and echocardiography, routine laboratory, autoimmune diagnostics) as well as demographic data were recorded retrospectively at the time of sample collection. Statistical analysis was performed using the Mann-Whitney U test (MWU), Pearson correlations, ROC analysis, and age-adjusted logistic regression models.

Results:

In SSc 20 of 28 measured ab levels are significantly altered compared to HC. According to the Pearson correlation matrix, the ab-levels are highly correlated and build a network that differs between HC and SSc. Furthermore, altered network signatures are formed in the differentiated analysis of several disease manifestations of SSc such as SSc-subtype or PF. Based on ROC analysis, FGF-ab, ADRB1-ab and PlGF-ab are well suited to predict SSc (Figure 1).

In addition, limited cutaneous SSc (lSSc) patients displayed lower levels of most ab than diffuse cutaneous SSc patients, whereas cardiac and pulmonary involvement are associated with higher ab levels. In the logistic regression lSSc is associated with lower levels of ab against M1R, M2R, C5aR, ETAR, AT1R, PAR1, EGFR. Higher levels for ab against M1R, M2R, ETBR, C5aR are associated with PF, higher levels of ab against complement receptors, adrenoreceptors and EGF with NT-proBNP elevation.

Conclusion:

The newly described antibodies against GPCR, GF and GFR are highly correlated. Associations with morbidity- and mortality-determining organ involvement indicate their possible functional relevance and novel pathophysiological mechanisms. As new biomarkers, some of the ab have prognostic value for SSc; for other manifestations, their value should be evaluated in further studies.

References:

[1]Cabral-Marques, O., Marques, A., Giil, L.M. et al. GPCR-specific autoantibody signatures are associated with physiological and pathological immune homeostasis. Nat Commun9, 5224 (2018). https://doi.org/10.1038/s41467-018-07598-9

[2]Riemekasten G, Philippe A, Näther M, et al. Involvement of functional autoantibodies against vascular receptors in systemic sclerosis Annals of the Rheumatic Diseases 2011;70:530-536.

[3]Weigold, F., Günther, J., Pfeiffenberger, M. et al. Antibodies against chemokine receptors CXCR3 and CXCR4 predict progressive deterioration of lung function in patients with systemic sclerosis. Arthritis Res Ther 20, 52 (2018). https://doi.org/10.1186/s13075-018-1545-8

Disclosure of Interests:

Kristina Sterner: None declared, Césaire J. K. Fouodo: None declared, Inke König: None declared, Axel Künstner: None declared, Hauke Busch: None declared, Harald Heidecke Shareholder of: Owner of CellTrend, Anja Schumann: None declared, Antje Müller: None declared, Gabriela Riemekasten: None declared, Susanne Schinke Grant/research support from: UCB sponsors EULAR registration fees

OP0054 NEW ROLE FOR PROTEINASE 3 IN IL-16 BIOACTIVITY CONTROL IN GRANULOMATOSIS WITH POLYANGIITIS

Background:

The immunomodulatory cytokine IL-16 is increased in several inflammatory and autoimmune diseases1. IL-16 recruits and activates CD4+ immune cells such as T cells, dendritic cells, or monocytes. IL-16 is produced by various immune and non-immune cells, but synthesis and storage of IL-16 is regulated differentially depending on the cell type and stimulation. For its biological activity, IL-16 cleavage by caspase-3 is required1. Necrotizing granulomatous inflammation is a hallmark of granulomatosis with polyangiitis (GPA) with neutrophil dysregulation as a central driver of chronic inflammation and autoimmunity2. Earlier studies showed a correlation between increased serum IL-16 and disease parameters in AAV, including GPA3, but functional evidence for a direct link between IL-16 and neutrophils in granulomatous inflammation is missing so far.

Objectives:

In this study we aim to identify a functional link between increased IL-16, neutrophils, and the autoantigen proteinase 3 (PR3) with regard to chronic inflammation and autoimmunity in GPA.

Methods:

IL-16 was measured in sera of GPA patients (n = 40) and healthy controls (HC, n = 50) by ELISA and correlated with clinical features, such as disease activity (BVAS), creatinine, GFR, VDI and PR3-ANCA status. IL-16 protein expression was analyzed in peripheral blood mononuclear cells (PBMC) and polymorphonuclear cells (PMN) from GPA patients and HC (n = 5, each) by SDS-PAGE and western blot. Binding affinity of recombinant pro-IL-16 to native human PR3 was assessed by microscale thermophoresis. Cleavage of pro-IL-16 by active human PR3 was performed at various time points at 37°C. Cleavage products were analyzed by SDS-PAGE and western blot.

Results:

Circulating IL-16 was significantly increased in GPA patients compared to HC. Elevated IL-16 positively correlated with BVAS, creatinine, VDI and PR3-ANCA status and negatively correlated with GFR. In PMBC and PMN from GPA and HC we identified different expression patters of precursor and active forms of IL-16. In healthy PBMC we found high amounts of precursor (80kD), pro-IL-16 (55kD) and active IL-16 (17kD). In contrast, PBMC from GPA patients had lower amounts of pro-IL-16 and no active IL-16, indicating activation and secretion of IL-16 due to inflammatory stimulation, as shown earlier5. In GPA PMN we detected no precursor IL-16, but pro-IL-16 and its active form, in contrast to very low amounts of all IL-16 forms in healthy PMN. Processing and release of IL-16 in neutrophils has been linked to apoptosis and secondary necrosis5. By interaction studies we demonstrated direct binding of pro-IL-16 to PR3 with a Kd of 10 nM. In a subsequent cleavage assay we confirmed IL-16 processing by PR3 in a time-dependent manner.

Conclusion:

Correlation of serum IL-16 with clinical features of GPA suggests that IL-16 is associated with markers of disease activity, tissue damage and autoreactivity. We showed that PBMC and PMN represent a source of IL-16 in GPA. By the identification of PR3 as an additional IL-16-activating enzyme we could demonstrate a potential link between excessive PR3 expression, cell death and IL-16-dependent mechanisms, contributing to chronic granulomatous inflammation and autoimmunity in GPA.

References:

[1]Glass, W. G. et al. Not-so-sweet sixteen: The role of IL-16 in infectious and immune-mediated inflammatory diseases. J. Interf. Cytokine Res. 26, 511–520 (2006).

[2]Millet, A. et al. Proteinase 3 on apoptotic cells disrupts immune silencing in autoimmune vasculitis. J. Clin. Invest. 125, 4107–4121 (2015).

[3]Yoon, T. et al. Serum interleukin-16 significantly correlates with the Vasculitis Damage Index in antineutrophil cytoplasmic antibody-associated vasculitis. Arthritis Res. Ther. 22, 1–6 (2020).

[4]Elssner, A. et al. IL-16 Is Constitutively Present in Peripheral Blood Monocytes and Spontaneously Released During Apoptosis. J. Immunol. 172, 7721–7725 (2004).

[5]Roth, S. et al. Secondary necrotic neutrophils release interleukin-16C and macrophage migration inhibitory factor from stores in the cytosol. Cell Death Discov. 1, 15056 (2015).

Disclosure of Interests:

None declared

Outcome measurement in trauma surgery with a fracture database and clinical and patient-reported outcome measures (PROMs)

Objective

Patient-Reported Outcome Measures (PROMs) gain growing attention. The Food and Drug Administration suggested in 2009 to have PROMs for every new treatment and technology. The use of PROMs was further promoted by the Patient Protection and Affordable Care Act of 2010 in the USA. Recommendations from other national and international organizations include the OECD's Project of Patient-Reported Indicator Surveys (PaRIS) and the International Consortium for Health Outcomes Measurement (ICHOM). Our development and initiation of a Fracture Database started early in 2018. We orientated our database on the role model of the Swedish Fracture Registry.

Methods

REDCap (Research Electronic Data Capture) is a web interface for a SQL (Structured Query Language)-Database. We used it to program the Fracture Registry. We collect data about demographics, diagnosis, treatment, adverse events, clinical outcomes, and PROMs. The PROMS are recorded with the Software 'Heartbeat ONE' vs. 6.15.4. Inclusion criteria are all patients with fractures of the upper and lower extremity, including the pelvis and multiple injuries, treated surgically. Excluded are all patients with fractures of the hand as monotrauma and non-surgical treatment. We established questionnaire sets for each anatomical region. Every hospitalized patient is screened for inclusion criteria to get the baseline PROMs. Follow-up PROMs are collected at 3-months and 12-months in our outpatient clinic.

Results

In five months of collecting PROMs, we have evaluated 599 patients, 521 fulfilling the inclusion criteria. 329 (63%) questionnaire sets were completed. The mean time for answering the questions was 11-20 minutes. The input rate of 63% for PROMs accounts for the start of the process, with 22 (4%) patients being dismissed before answering the questionnaires. 93 (18%) patients denied participation. 52 (10%) patients were not able to participate (dementia, delirium). Other causes for missing data were language barriers (n = 28; 5%), medical reasons like polytraumatized patients (n = 4; 0.8%), and deceased patients (n = 15; 2.9%).

Conclusion

Most Orthopaedic Trauma centers publish data about PROMs from surgically treated patients. Starting in the first quarter of 2021, we will include non-surgically treated patients. We have optimized the process of including patients. Our aim is a response rate of more than 80% within this year to get representing data.

Low-Dose IL-2 Therapy in Autoimmune and Rheumatic Diseases

Regulatory T cells (Treg) are crucial for the maintenance of peripheral tolerance and for the control of ongoing inflammation and autoimmunity. The cytokine interleukin-2 (IL-2) is essentially required for the growth and survival of Treg in the peripheral lymphatic tissues and thus plays a vital role in the biology of Treg. Most autoimmune and rheumatic diseases exhibit disturbances in Treg biology either at a numerical or functional level resulting in an imbalance between protective and pathogenic immune cells. In addition, in some autoimmune diseases, a relative deficiency of IL-2 develops during disease pathogenesis leading to a disturbance of Treg homeostasis, which further amplifies the vicious cycle of tolerance breach and chronic inflammation. Low-dose IL-2 therapy aims either to compensate for this IL-2 deficiency to restore a physiological state or to strengthen the Treg population in order to be more effective in counter-regulating inflammation while avoiding global immunosuppression. Here we highlight key findings and summarize recent advances in the clinical translation of low-dose IL-2 therapy for the treatment of autoimmune and rheumatic diseases.

Aspect ratio of nano/microstructures determines Staphylococcus aureus adhesion on PET and titanium surfaces

AIMS

Joint infections cause premature implant failure. The avoidance of bacterial colonization of implant materials by modification of the material surface is therefore the focus of current research. In this in vitro study the complex interaction of periodic structures on PET and titanium surfaces on the adhesion of Staphylococcus aureus is analysed.

METHODS AND RESULTS

Using direct laser interference patterning as well as roll-to-roll hot embossing methods, structured periodic textures of different spatial distance were produced on surfaces and S. aureus were cultured for 24 h on these. The amount of adhering bacteria was quantified using fluorescence microscopy and the local adhesion behaviour was investigated using scanning electron microscopy. For PET structures, minimal bacterial adhesion was identified for an aspect ratio of about 0·02. On titanium structures, S. aureus adhesion was significantly decreased for profile heights of < 200 nm. Our results show a significantly decreased bacterial adhesion for structures with an aspect ratio range of 0·02 to 0·05.

CONCLUSIONS

We show that structuring on surfaces can decrease the amount of S. aureus on titanium and PET as common implant materials.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study highlights the immense potential of applying specific structures to implant materials to prevent implant colonization with pathogen bacteria.

Associations between minerals and metabolic indicators in maternal blood pre- and postpartum with ewe body condition, methane emissions, and lamb body weight development

In sheep production, economic efficiency strongly depends on the maternal health and feed efficiency status and on weaning performances of their offspring. Accordingly, an optimal level for the supply with macro- and microelements and the ewe energy status has impact on the fetal development during gestation and on maternal milk production during lactation. Furthermore, this study addressed intergenerational aspects, i.e., on associations between maternal energy metabolism profiles considering the macro- and microelement status, metabolic indicators (e.g. β-hydroxybutyrate (BHB)), body condition and methane (CH4) emissions with lamb BW (LBW) in two sheep breeds. Traits were recorded at the beginning of gestation (ewe traits), at lambing, three weeks postpartum, and at weaning (ewe and lamb traits). Trait recording included CH4 emissions (recorded via laser methane detector (LMD)), ewe BW (EBW), backfat thickness (BFT), and body condition score (BCS) from 46 ewes (24 Merinoland- (ML), 22 Rhönsheep (RH)), and LBW of their 87 (35 ML, 52 RH) purebred lambs. Serum levels of the following ewe blood parameters were determined: calcium (Ca), sodium (Na), potassium (K), phosphate (P), nonesterified fatty acids (NEFA), BHB, glutamate dehydrogenase (GLDH), selenium (Se), copper (Cu), iron (Fe), zinc (Zn), and magnesium (Mg). Mixed models were applied to infer associations between ewe blood parameters with EBW, BFT, BCS, and CH4 and with LBW recorded in offspring. At weaning, a maternal serum Mg level > 1.0 mmol/L was significantly associated with an increase of 13% in LBW in ML, compared to offspring from ML ewes with a serum Mg concentration within the lower reference range (0.8 mmol/L). Furthermore, higher Cu levels were favorably associated with ewe BCS and BFT at weaning in both breeds. In RH ewes, a Se level > 2.4 μmol/l was significantly associated with increased BCS. In the ML breed, high Zn levels during lactation were associated with reduced CH4 emissions. Ewe EBW was significantly larger for ML ewes representing low Ca levels. A low BHB level was associated with decreasing CH4 emissions in RH and ML. Serum levels for Na, K, P, GLDH, and Fe did not significantly affect the traits of interest. Trait associations from the present study indicate the importance of the mineral supply and metabolic status of the ewe with regard to body condition, CH4 emissions, and LBW development, but depending on the breed. Identified associations might contribute to energy efficiency in sheep production systems.

Disentangling the Photodissociation Dynamics of the HF+ Molecular Radical via Kinetic-Energy-Release-Resolved F 1s Core Excitation and Ionization

The F 1s core level photoionization of the ionic molecular radical HF⁺ has been studied using the photon-ion merged-beams technique at a synchrotron radiation source. Upon analyzing kinetic energy release (KER) dependent photoion yield spectra, complex ultrafast dissociation dynamics of the F 1s core hole excited σ* state can be revealed. By means of configuration-interaction electronic structure calculations of the excited molecular potential energy curves, this complex process can be attributed to a spin-dependent dissociation of the excited σ* biradical state.

Brain/blood ratios of methadone and ABCB1 polymorphisms in methadone-related deaths

Methadone is an opioid that often leads to fatalities. Interpretation of toxicological findings can be challenging if no further information about the case history is available. The aims of this study were (1) to determine whether brain/blood ratios can assist in the interpretation of methadone findings in fatalities; (2) to examine whether polymorphisms in the gene encoding the P-glycoprotein (also known as multidrug resistance protein 1 (MDR1) or ATP-binding cassette sub-family B member 1 (ABCB1)), which functions as a multispecific efflux pump in the blood–brain barrier, affect brain/blood ratios of methadone. Femoral venous blood and brain tissue (medulla oblongata and cerebellum) from 107 methadone-related deaths were analysed for methadone by gas chromatography-mass spectrometry. In addition, all the samples were genotyped for three common ABCB1 single nucleotide polymorphisms (SNPs rs1045642, rs1128503, and rs2032582) using ion-pair reversed-phase high-performance liquid chromatography-electrospray ionization mass spectrometry (ICEMS). In nearly all cases, methadone concentrations were higher in the brain than in the blood. Inter-individual brain/blood ratios varied (0.6–11.6); the mean ratio was 2.85 (standard deviation 1.83, median 2.35). Moreover, significant differences in mean brain/blood ratios were detected among the synonymous genotypes of rs1045642 in ABCB1 (p = 0.001). Cases with the T/T genotype had significantly higher brain/blood ratios than cases with the other genotypes (T/T vs. T/C difference (d) = 1.54, 95% CI [1.14, 2.05], p = 0.002; T/T vs. C/C d = 1.60, 95% CI [1.13, 2.29], p = 0.004). Our results suggest that the rs1045642 polymorphisms in ABCB1 may affect methadone concentrations in the brain and its site of action and may be an additional factor influencing methadone toxicity.