EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice: 2023 update

OBJECTIVES

To update the EULAR recommendations for the use of imaging modalities in primary large vessel vasculitis (LVV).

METHODS

A systematic literature review update was performed to retrieve new evidence on ultrasound, MRI, CT and [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) for diagnosis, monitoring and outcome prediction in LVV. The task force consisted of 24 physicians, health professionals and patients from 14 countries. The recommendations were updated based on evidence and expert opinion, iterating until voting indicated consensus. The level of agreement was determined by anonymous votes.

RESULTS

Three overarching principles and eight recommendations were agreed. Compared to the 2018 version, ultrasound is now recommended as first-line imaging test in all patients with suspected giant cell arteritis, and axillary arteries should be included in the standard examination. As an alternative to ultrasound, cranial and extracranial arteries can be examined by FDG-PET or MRI. For Takayasu arteritis, MRI is the preferred imaging modality; FDG-PET, CT or ultrasound are alternatives. Although imaging is not routinely recommended for follow-up, ultrasound, FDG-PET or MRI may be used for assessing vessel abnormalities in LVV patients with suspected relapse, particularly when laboratory markers of inflammation are unreliable. MR-angiography, CT-angiography or ultrasound may be used for long-term monitoring of structural damage, particularly at sites of preceding vascular inflammation.

CONCLUSIONS

The 2023 EULAR recommendations provide up-to-date guidance for the role of imaging in the diagnosis and assessment of patients with LVV.

JAK/STAT signaling in rheumatoid arthritis leukocytes is uncoupled from serum cytokines in a subset of patients

OBJECTIVE

Rheumatoid Arthritis (RA) is a systemic autoimmune disease involving pro-inflammatory cytokines that can be therapeutically targeted by antibodies or kinase inhibitors. Nevertheless, these drugs fail in a subset of patients independent of the abundance of the targeted cytokines. We aim to explore the cellular basis of this phenomenon by analyzing the relation of cytokine abundance and activation of downstream signaling pathways in RA.

METHODS

The study included 62 RA patients and 9 healthy controls (HC). Phosphorylation of STAT 1-6 in various immune cell subsets was determined ex vivo using a novel robust flow cytometry-based protocol. Serum concentrations of IL-6, IL-10, IL-12p70, IL-17 A, interferon gamma, and TNF-alpha in the same samples were measured using highly sensitive single molecule array (SIMOA).

RESULTS

We found an increase in circulating cytokines in RA patients, while STAT activity was lower in RA patients compared to HC. Based on STAT activity we determined three endotypes in active RA patients (cDAI>10, n = 28): 1) those with active STAT5a/b signaling in T cells (n = 7/28), 2) those with a low STAT activity in all assessed cell types (n = 14/28), and 3) those with active STAT1 and STAT3 signaling mainly in myeloid cells (n = 7/28). Integrating intracellular STAT activation and cytokine analysis revealed diminished JAK/STAT signaling in a subset of patients (n = 8/20) despite elevated serum cytokine concentrations.

CONCLUSION

Diminished JAK/STAT signaling in active RA may partly explain unresponsiveness to therapy targeting cytokine signaling. Analysis of JAK/STAT phosphorylation may identify patients at risk for non-response to these therapies.

Cranial involvement in giant cell arteritis

Since its first clinical description in 1890, extensive research has advanced our understanding of giant cell arteritis, leading to improvements in both diagnosis and management for affected patients. Imaging studies have shown that the disease frequently extends beyond the typical cranial arteries, also affecting large vessels such as the aorta and its proximal branches. Meanwhile, advances in comprehending the underlying pathophysiology of giant cell arteritis have given rise to numerous potential therapeutic agents, which aim to minimise the need for glucocorticoid treatment and prevent flares. Classification criteria for giant cell arteritis, as well as recommendations for management, imaging, and treat-to-target have been developed or updated in the last 5 years, and current research encompasses a broad spectrum covering basic, translational, and clinical research. In this Series paper, we aim to discuss the current understanding of giant cell arteritis with cranial manifestations, describe the clinical approach to this condition, and explore future directions in research and patient care.

The association between comorbidities and disease activity in spondyloarthritis - A narrative review

Comorbidities, including cardiovascular disease, osteoporosis, and depression, are more prevalent in patients with spondyloarthritis (SpA) than in the general population. Clinical and laboratory markers of disease activity are associated with numerous of these comorbidities, and studies suggest that the treatment of SpA can have a positive impact on comorbidities; conversely, managing comorbidities can improve disease activity. Therefore, the screening of comorbidities is considered a core component of a rheumatology consultation, and treatment should be performed in liaison with other health professionals (e.g. general physicians). Validated tools and questionnaires can be used for not only the detection but also the monitoring of potential comorbidities. Understanding whether a comorbidity is a separate disease entity, linked to SpA or its treatment, or an extra-musculoskeletal manifestation of the disease is important to identify the most appropriate treatment options.

Imaging in diagnosis, monitoring and outcome prediction of large vessel vasculitis: a systematic literature review and meta-analysis informing the 2023 update of the EULAR recommendations

OBJECTIVES

To update the evidence on imaging for diagnosis, monitoring and outcome prediction in large vessel vasculitis (LVV) to inform the 2023 update of the European Alliance of Associations for Rheumatology recommendations on imaging in LVV.

METHODS

Systematic literature review (SLR) (2017-2022) including prospective cohort and cross-sectional studies (>20 participants) on diagnostic, monitoring, outcome prediction and technical aspects of LVV imaging. Diagnostic accuracy data were meta-analysed in combination with data from an earlier (2017) SLR.

RESULTS

The update retrieved 38 studies, giving a total of 81 studies when combined with the 2017 SLR. For giant cell arteritis (GCA), and taking clinical diagnosis as a reference standard, low risk of bias (RoB) studies yielded pooled sensitivities and specificities (95% CI) of 88% (82% to 92%) and 96% (95% CI 86% to 99%) for ultrasound (n=8 studies), 81% (95% CI 71% to 89%) and 98% (95% CI 89% to 100%) for MRI (n=3) and 76% (95% CI 67% to 83%) and 95% (95% CI 71% to 99%) for fluorodeoxyglucose positron emission tomography (FDG-PET, n=4), respectively. Compared with studies assessing cranial arteries only, low RoB studies with ultrasound assessing both cranial and extracranial arteries revealed a higher sensitivity (93% (95% CI 88% to 96%) vs 80% (95% CI 71% to 87%)) with comparable specificity (94% (95% CI 83% to 98%) vs 97% (95% CI 71% to 100%)). No new studies on diagnostic imaging for Takayasu arteritis (TAK) were found. Some monitoring studies in GCA or TAK reported associations of imaging with clinical signs of inflammation. No evidence was found to determine whether imaging severity might predict worse clinical outcomes.

CONCLUSION

Ultrasound, MRI and FDG-PET revealed a good performance for the diagnosis of GCA. Cranial and extracranial vascular ultrasound had a higher pooled sensitivity with similar specificity compared with limited cranial ultrasound.

The provisional OMERACT ultrasonography score for giant cell arteritis

OBJECTIVES

To develop an Outcome Measures in Rheumatology (OMERACT) ultrasonography score for monitoring disease activity in giant cell arteritis (GCA) and evaluate its metric properties.

METHODS

The OMERACT Instrument Selection Algorithm was followed. Forty-nine members of the OMERACT ultrasonography large vessel vasculitis working group were invited to seven Delphi rounds. An online reliability exercise was conducted using images of bilateral common temporal arteries, parietal and frontal branches as well as axillary arteries from 16 patients with GCA and 7 controls. Sensitivity to change and convergent construct validity were tested using data from a prospective cohort of patients with new GCA in which ultrasound-based intima-media thickness (IMT) measurements were conducted at weeks 1, 3, 6, 12 and 24.

RESULTS

Agreement was obtained (92.7%) for the OMERACT GCA Ultrasonography Score (OGUS), calculated as follows: sum of IMT measured in every segment divided by the rounded cut-off values of IMTs in each segment. The resulting value is then divided by the number of segments available. Thirty-five members conducted the reliability exercise, the interrater intraclass correlation coefficient (ICC) for the OGUS was 0.72-0.84 and the median intrareader ICC was 0.91. The prospective cohort consisted of 52 patients. Sensitivity to change between baseline and each follow-up visit up to week 24 yielded standardised mean differences from -1.19 to -2.16, corresponding to large and very large magnitudes of change, respectively. OGUS correlated moderately with erythrocyte sedimentation rate, C reactive protein and Birmingham Vasculitis Activity Score (corrcoeff 0.37-0.48).

CONCLUSION

We developed a provisional OGUS for potential use in clinical trials.

EULAR points to consider for the use of imaging to guide interventional procedures in patients with rheumatic and musculoskeletal diseases (RMDs)

OBJECTIVES

To develop evidence-based Points to Consider (PtC) for the use of imaging modalities to guide interventional procedures in patients with rheumatic and musculoskeletal diseases (RMDs).

METHODS

European Alliance of Associations for Rheumatology (EULAR) standardised operating procedures were followed. A systematic literature review was conducted to retrieve data on the role of imaging modalities including ultrasound (US), fluoroscopy, MRI, CT and fusion imaging to guide interventional procedures. Based on evidence and expert opinion, the task force (25 participants consisting of physicians, healthcare professionals and patients from 11 countries) developed PtC, with consensus obtained through voting. The final level of agreement was provided anonymously.

RESULTS

A total of three overarching principles and six specific PtC were formulated. The task force recommends preference of imaging over palpation to guide targeted interventional procedures at peripheral joints, periarticular musculoskeletal structures, nerves and the spine. While US is the favoured imaging technique for peripheral joints and nerves, the choice of the imaging method for the spine and sacroiliac joints has to be individualised according to the target, procedure, expertise, availability and radiation exposure. All imaging guided interventions should be performed by a trained specialist using appropriate operational procedures, settings and assistance by technical personnel.

CONCLUSION

These are the first EULAR PtC to provide guidance on the role of imaging to guide interventional procedures in patients with RMDs.

POS1063 STAT PHOSPHORYLATION AS A MARKER FOR DISEASE ACTIVITY IN PATIENTS WITH PSORIATIC ARTHRITIS: AN EXPLORATIVE ANALYSIS

Background

Numerous cytokines that influence disease activity in psoriatic arthritis (PsA) are modulators of the Janus Kinases/Signal Transducers and Activators of Transcription (JAK/STAT) pathway. The JAK1/STAT1/STAT3/STAT5 network can drive the expansion of Th17 and regulatory T cells via proinflammatory cytokines in PsA joints,[1], [2] while hyperphosphorylation of STAT3 in immune cells has previously been shown to promote PsA pathogenesis through the Interleukin (IL)-23/IL-17/IL-22 axis.[3] Therefore, the phosphorylation status of STAT molecules in leucocytes of PsA patients may indicate active disease and could potentially guide treatment with JAK inhibitors.

Objectives

To analyse phosphorylated STAT (pSTAT) levels of circulating leucocyte subsets in PsA patients with active and inactive disease

Methods

Whole blood was drawn on consecutive PsA patients fulfilling the CASPAR criteria[4] to perform flow cytometry analysis using the BD FACSLyric platform. Disease activity was assessed using the Disease activity for psoriasis arthritis (DAPSA) score.[5] All steps from storage of drawn blood to cell fixation were performed at 4°C to prevent auto-activation of leucocytes. The geometric mean fluorescence intensities (gMFI) of pSTATs in granulocytes, monocytes, B cells and CD4+/- naïve/memory T cells were compared between patients with moderate to high (MoDA/HDA) and remission to low disease activity (REM/LDA). Correlation analysis between gMFIs and DAPSA scores were performed.

Results

Forty-two patients (female ratio: 0.48) with established PsA (median ± standard deviation, age: 56 ± 12.54 years, disease duration: 8.50 ± 7.10 years) were included in this study. Twenty-one percent of patients were in MoDA/HDA, while the remaining 79% were in REM/LDA. Patients in MoDA/HDA showed significantly higher pSTAT3 levels in CD4+ naïve (gMFI median ± standard deviation: 284.5 ± 79.9 vs 238 ± 92.9, p = 0.011), CD4- naïve (297 ± 107.5 vs 238 ± 98.4, p = 0.04), CD4+ memory (227 ± 62.9 vs 190.5 ± 72.2, p = 0.009) and CD4- memory T cells (209 ± 66.8 vs 167.0 ± 64.9, p = 0.036). On the other hand, PsA patients in remission or low disease activity displayed higher pSTAT1 levels in granulocytes (2509 ± 1887 vs 1330.5 ± 784.1, p = 0.040) and monocytes (255 ± 230 vs 144 ± 62.5, p = 0.049). Positive correlations were found between DAPSA scores and pSTAT3 in CD4+ naïve and memory T cells (Spearman’s correlation coefficient rho (ρ) = 0.5, p = 0.0012 and ρ = 0.47, p = 0.0025 resp.) whereas pSTAT1 in granulocytes and monocytes were negatively correlated with the DAPSA scores (ρ = -0.45, p = 0.0074 and ρ = -0.34, p = 0.05).

Conclusion

Differential phosphorylation of STAT3 and STAT1 molecules in circulating leucocyte subsets indicates PsA disease activity. Further studies to examine the value of STAT phosphorylation patterns guiding JAK inhibitor therapy are underway.

References

[1]U. Fiocco et al., “Ex vivo signaling protein mapping in T lymphocytes in the psoriatic arthritis joints,” J. Rheumatol., vol. 93, pp. 48–52, 2015, doi: 10.3899/jrheum.150636.

[2]S. K. Raychaudhuri, C. Abria, and S. P. Raychaudhuri, “Regulatory role of the JAK STAT kinase signalling system on the IL-23/IL-17 cytokine axis in psoriatic arthritis,” Ann. Rheum. Dis., vol. 76, no. 10, pp. e36–e36, 2017.

[3]E. Calautti, L. Avalle, and V. Poli, “Psoriasis: A STAT3-centric view,” International Journal of Molecular Sciences, vol. 19, no. 1. MDPI AG, Jan. 06, 2018, doi: 10.3390/ijms19010171.

[4]W. Taylor, D. Gladman, P. Helliwell, A. Marchesoni, P. Mease, and H. Mielants, “Classification criteria for psoriatic arthritis: Development of new criteria from a large international study,” Arthritis Rheum., vol. 54, no. 8, pp. 2665–2673, 2006, doi: 10.1002/art.21972.

[5]M. M. Schoels, D. Aletaha, F. Alasti, and J. S. Smolen, “Disease activity in psoriatic arthritis (PsA): Defining remission and treatment success using the DAPSA score,” Ann. Rheum. Dis., vol. 75, no. 5, pp. 811–818, 2016, doi: 10.1136/annrheumdis-2015-207507.

Disclosure of Interests

Barbara Dreo: None declared, Daniel Ruben Pietsch: None declared, Rusmir Husic Speakers bureau: MSD, Lilly und Abbvie, Angelika Lackner: None declared, Johannes Fessler: None declared, Janine Rupp: None declared, Anirudh Subramanian Muralikrishnan: None declared, Jens Thiel Speakers bureau: GSK, BMS, AbbVie, Novartis, Consultant of: GSK, Novartis, Grant/research support from: BMS, Martin Stradner Speakers bureau: Eli Lilly, Pfizer, MSD, BMS, AbbVie, Janssen, Consultant of: Eli Lilly, AbbVie, Janssen, Philipp Bosch Grant/research support from: Pfizer

POS0380 EFFECTIVENESS OF REMOTE CARE INTERVENTIONS: A SYSTEMATIC REVIEW INFORMING THE 2022 EULAR POINTS TO CONSIDER FOR REMOTE CARE IN RHEUMATIC AND MUSCULOSKELETAL DISEASES

Background

While the number of patients with rheumatic musculoskeletal diseases (RMDs) is increasing worldwide, there is no adequate increment in the number of health care professionals, leading to the urgent need for new forms of care to take pressure from health care systems.1 2 Telehealth comprises a number of different types of interventions with the scope of performing certain steps of care, ranging from diagnostics to follow-up visits, in a remote manner. The use of remote care is heterogenous and guidance is needed to optimize the combination with conventional face-to-face (F2F) visits.

Objectives

To perform a systematic literature review (SLR) on different outcomes of remote care compared to F2F care, its implementation into clinical practice and to identify drivers and barriers in order to inform a task force formulating the European Alliance of Associations for Rheumatology (EULAR) Points to Consider for remote care in RMDs.

Methods

Prospective, retrospective, and qualitative studies testing different types of remote care in patients with RMDs were included. Medline, Embase and the Cochrane Library were searched through February 28th, 2021. Two reviewers independently performed standardized data extraction, synthesis, and risk of bias assessment.

Results

A total of 2,240 references were identified. Forty-seven studies, consisting of 26 randomized controlled trials, 8 prospective cohort studies, 8 cross sectional studies, and 5 qualitative studies were included.

Fifty-one percent of the studies involved patients with inflammatory RMDs, including rheumatoid arthritis, and spondyloarthritis, while 49% were on patients with non-inflammatory conditions, such as osteoarthritis and fibromyalgia. Remote monitoring (n=35) was most frequently studied, with telephone/video calls being the most common mode of delivery (n=30). Thirty-four studies investigated outcomes of remote care in comparison to F2F care. The most frequently assessed outcomes concerned efficacy and user perception of remote care, with 34% and 21% of studies, respectively, reporting superior results for the remote care intervention.

Time savings and flexibility were reported as major drivers, while inadequate technical knowledge and concerns in data security were the main barriers to implementing remote care. Implementation of remote care methods into clinical practice was not reported by the included studies. The main limitations were the heterogeneity of outcomes and interventions, and the substantial risk of bias (50% of studies with high risk of bias).

Conclusion

Studies on remote care reported similar to partially better results compared to F2F care concerning efficacy, and user perception outcomes, with the limitation of heterogeneity and considerable risk of bias.

References

[1]World Health Organization. WHO Guideline: recommendations on digital interventions for helath system strengthening. 2019 [Available from: https://apps.who.int/iris/bitstream/handle/10665/311941/9789241550505-eng.pdf?ua=1 accessed 10.01.2022.

[2]James SL, Abate D, Abate KH, et al. Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017. Lancet 2018;392(10159):1789-858. doi: https://doi.org/10.1016/S0140-6736(18)32279-7

Disclosure of Interests

Andrea Marques: None declared, Philipp Bosch: None declared, Annette de Thurah Speakers bureau: Pfizer, Eli Lily, Grant/research support from: Novartis, Yvette Meissner Speakers bureau: Pfizer, Louise Falzon: None declared, Chetan Mukhtyar: None declared, Hans Bijlsma Speakers bureau: Abbvie, Arthrogen, BMS, Lilly, MSD, Pfizer, Roche, Sun, UCB, Consultant of: Abbvie, Arthrogen, BMS, Lilly, MSD, Pfizer, Roche, Sun, UCB, Grant/research support from: Roche, Sun, Christian Dejaco Speakers bureau: Abbvie, Eli Lilly, Janssen, Novartis, Pfizer, Roche, Galapagos, Sanofi, Consultant of: Abbvie, Eli Lilly, Janssen, Novartis, Pfizer, Roche, Galapagos, Sanofi, Grant/research support from: Celgene, Pfizer, Tanja Stamm Speakers bureau: AbbVie, Roche, Sanofi, Takeda, Consultant of: Abbvie, Sanofi, Grant/research support from: Abbvie, Roche

Ultrasound-detected inflammation is more common in clinically manifest hand osteoarthritis than in painless bony enlarged finger joints: subanalysis of the population-based Bruneck study

Purpose:

The aim of this article is to examine the extent of structural and inflammatory lesions by ultrasound in elderly subjects with hand osteoarthritis (HOA) fulfilling the ACR classification criteria (Group A), in subjects with painless enlarged finger joints (Group B), and in individuals without clinical abnormalities at hands (Group C).

Methods:

This study was nested within the population-based, prospective Bruneck study; 293 subjects of ⩾65 years of age were assessed. Clinical and ultrasound assessment was conducted at wrists and finger joints. Gray scale synovitis (GSS), Power Doppler (PD), osteophytes, and erosions were scored semiquantitatively (0–3). The Short Form Score for the Assessment and Quantification of Chronic Rheumatic Affections of the Hands (SF-SACRAH), the Health Assessment Questionnaire (HAQ), and the Functional Index for Hand Osteoarthritis (FIHOA) were retrieved.

Results:

Most subjects had ⩾1 ultrasound abnormality, of which osteophytes were the most prevalent finding in all groups (Group A: 100%, Group B: 99.4%, and Group C: 93.9%). GSS and PD-signals were more common in Group A than in Group B (94% versus 67% and 33% versus 13%, respectively). In Group C, GSS was observed in 39.4% of subjects. In subjects with HOA, the SF-SACRAH correlated with osteophyte scores (corr_coeff = 0.48), and the FIHOA correlated with the osteophyte (corr_coeff = 0.42) and PD scores (corr_coeff = 0.33).

Conclusion:

GSS and PD were more frequent in patients with symptomatic HOA than in cases with painless bony enlargements and subjects without clinical joint abnormalities. Functional restriction in HOA is associated with structural and inflammatory ultrasound changes.

Effectiveness of remote care interventions: a systematic review informing the 2022 EULAR Points to Consider for remote care in rheumatic and musculoskeletal diseases

Objective

To perform a systematic literature review (SLR) on different outcomes of remote care compared with face-to-face (F2F) care, its implementation into clinical practice and to identify drivers and barriers in order to inform a task force formulating the EULAR Points to Consider for remote care in rheumatic and musculoskeletal diseases (RMDs).

Methods

A search strategy was developed and run in Medline (PubMed), Embase and Cochrane Library. Two reviewers independently performed standardised data extraction, synthesis and risk of bias (RoB) assessment.

Results

A total of 2240 references were identified. Forty-seven of them fulfilled the inclusion criteria. Remote monitoring (n=35) was most frequently studied, with telephone/video calls being the most common mode of delivery (n=30). Of the 34 studies investigating outcomes of remote care, the majority addressed efficacy and user perception; 34% and 21% of them, respectively, reported a superiority of remote care as compared with F2F care. Time and cost savings were reported as major benefits, technical aspects as major drawback in the 13 studies that investigated drivers and barriers of remote care. No study addressed remote care implementation. The main limitation of the studies identified was the heterogeneity of outcomes and methods, as well as a substantial RoB (50% of studies with high RoB).

Conclusions

Remote care leads to similar or better results compared with F2F treatment concerning efficacy, safety, adherence and user perception outcomes, with the limitation of heterogeneity and considerable RoB of the available studies.

2022 EULAR points to consider for remote care in rheumatic and musculoskeletal diseases

BACKGROUND

Remote care and telehealth have the potential to expand healthcare access, and the COVID-19 pandemic has called for alternative solutions to conventional face-to-face follow-up and monitoring. However, guidance is needed on the integration of telehealth into clinical care of people with rheumatic and musculoskeletal diseases (RMD).

OBJECTIVE

To develop EULAR points to consider (PtC) for the development, prioritisation and implementation of telehealth for people with RMD.

METHODS

A multidisciplinary EULAR task force (TF) of 30 members from 14 European countries was established, and the EULAR standardised operating procedures for development of PtC were followed. A systematic literature review was conducted to support the TF in formulating the PtC. The level of agreement among the TF was established by anonymous online voting.

RESULTS

Four overarching principles and nine PtC were formulated. The use of telehealth should be tailored to patient's needs and preferences. The healthcare team should have adequate equipment and training and have telecommunication skills. Telehealth can be used in screening for RMD as preassessment in the referral process, for disease monitoring and regulation of medication dosages and in some non-pharmacological interventions. People with RMD should be offered training in using telehealth, and barriers should be resolved whenever possible.The level of agreement to each statement ranged from 8.5 to 9.8/10.

CONCLUSION

The PtC have identified areas where telehealth could improve quality of care and increase healthcare access. Knowing about drivers and barriers of telehealth is a prerequisite to successfully establish remote care approaches in rheumatologic clinical practice.

The Digital Way to Intercept Psoriatic Arthritis

Psoriasis (PsO) and Psoriatic Arthritis (PsA) are chronic, immune-mediated diseases that share common etiopathogenetic pathways. Up to 30% of PsO patient may later develop PsA. In nearly 75% of cases, skin psoriatic lesions precede arthritic symptoms, typically 10 years prior to the onset of joint symptoms, while PsO diagnosis occurring after the onset of arthritis is described only in 15% of cases. Therefore, skin involvement offers to the rheumatologist a unique opportunity to study PsA in a very early phase, having a cohort of psoriatic “risk patients” that may develop the disease and may benefit from preventive treatment. Progression from PsO to PsA is often characterized by non-specific musculoskeletal symptoms, subclinical synovio-entheseal inflammation, and occasionally asymptomatic digital swelling such as painless toe dactylitis, that frequently go unnoticed, leading to diagnostic delay. The early diagnosis of PsA is crucial for initiating a treatment prior the development of significant and permanent joint damage. With the ongoing development of pharmacological treatments, early interception of PsA has become a priority, but many obstacles have been reported in daily routine. The introduction of digital technology in rheumatology may fill the gap in the physician-patient relationship, allowing more targeted monitoring of PsO patients. Digital technology includes telemedicine, virtual visits, electronic health record, wearable technology, mobile health, artificial intelligence, and machine learning. Overall, this digital revolution could lead to earlier PsA diagnosis, improved follow-up and disease control as well as maximizing the referral capacity of rheumatic centers.

[Telemedical care and IT-based systems in rheumatology]

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic and also the ever-increasing demands on the healthcare system, have led to a focus on the further development of telemedical services in rheumatology.

OBJECTIVE

What is the evidence for telemedical services in rheumatology?

MATERIAL AND METHODS

Narrative review of existing literature on telemedicine in rheumatology.

RESULTS

Electronic patient reported outcomes (ePROs) can be determined by patients from their home and sent electronically to the rheumatologist. In future, ePROs may help with the decision whether a patient needs to attend the clinic for a visit or the visit can be rescheduled due to remission and well-being. Telemedicine has already been used for well-controlled patients with rheumatic diseases with good results in terms of safety and disease activity compared to conventional face-to-face visits. Telemedicine represents an interesting tool for appointment prioritization and triaging, while automated algorithm-based applications are currently too imprecise for routine clinical use. The role of smartphone applications in the care of patients with rheumatic diseases is still unclear.

DISCUSSION

Telemedicine represents an interesting option for certain patient populations with rheumatic diseases. Apart from research on the effectiveness and safety of telemedical interventions, decision makers need to set clear rules on how telemedicine should be used to provide the best possible care for the individual patient.

Value of imaging to guide interventional procedures in rheumatic and musculoskeletal diseases: a systematic literature review informing EULAR points to consider

OBJECTIVES

To summarise current data on the value of imaging to guide interventional procedures in patients with rheumatic and musculoskeletal disease (RMDs) informing an European Alliance of Associations for Rheumatology taskforce.

METHODS

A systematic literature review was conducted to retrieve prospective and retrospective studies published in English and comparing different (imaging) techniques, different settings and procedural protocols to guide interventions in patients with RMDs. MEDLINE, EMBASE, the Cochrane Library and Epistemonikos databases were searched through October 2021. Risk of bias (RoB) was assessed using the Cochrane RoB tool for randomised trials V.2 (ROB2), the RoB tool for Non-Randomised Studies of Interventions and the appraisal tool for cross-sectional studies.

RESULTS

Sixty-six studies were included (most with moderate/high RoB); 49 were randomised controlled trials, three prospective cohort studies and 14 retrospective studies. Fifty-one studies compared either one imaging technique with another imaging technique, or with palpation-guided interventions. Ultrasound (US) was most frequently studied (49/51), followed by fluoroscopy (10/51). Higher accuracy was found for US or fluoroscopy compared with palpation-guided interventions. Studies comparing different imaging techniques (12/51) did not endorse one specific method. Different settings/equipment for imaging-guided procedures (eg, automatic vs manual syringes) were investigated in three studies, reporting heterogeneous results. Fifteen studies compared different imaging-guided procedures (eg, intra-articular vs periarticular injections).

CONCLUSION

Higher accuracy of needle positioning at joints and periarticular structures was seen in most studies when using imaging (especially US) guidance as compared with palpation-guided interventions with the limitation of heterogeneity of data and considerable RoB.

Current Practice of Imaging-Guided Interventional Procedures in Rheumatic and Musculoskeletal Diseases: Results of a Multinational Multidisciplinary Survey

Objectives: To investigate opinion and routine practice of specialists from different disciplines on imaging techniques for interventional procedures related to rheumatic and musculoskeletal diseases (RMDs). Methods: An English-language questionnaire was developed by an international working group and distributed to health care providers of various disciplines involved in the care of people with RMDs via an online survey tool (SoSci Survey®) from December 2019 to May 2020. Results: A total of 1,105 respondents from 56 countries completed the survey, over 60% of participants were rheumatologists. The majority of respondents (88%) performed interventional procedures in RMDs patients and 90% of them used imaging guidance. Ultrasonography was the most frequently used technique, particularly among rheumatologists. X-ray and computed tomography were mainly used by radiologists. A discrepancy emerged between the importance assigned to certain items such as the availability of a second operator and their actual implementation in clinical practice. Local barriers, lack of resources and facilities were mentioned as the most relevant obstacles in this regard. Lack of training on imaging and/or imaging guided procedures did not emerge as a barrier to perform such interventions; in fact, 19% of respondents performing the procedures indicated not to have received adequate training in this field. Conclusions: This is the first multinational multidisciplinary survey exploring in detail the opinions and practice on imaging guidance for interventional procedures in RMDs. A harmonization of protocols based on international guidelines, along with adequate training programmes and interventions on barriers at national/local levels are the main unmet needs requiring attention.

The role of tender and swollen joints for the assessment of inflammation in PsA using ultrasound

OBJECTIVE

To evaluate tender joints (TJ) and swollen joints (SJ) for the assessment of ultrasound (US) defined inflammation in PsA.

METHODS

Eighty-three PsA patients underwent clinical and US examinations at two scheduled study visits 12 months apart. Tenderness and swelling were assessed at 68 and 66 joints respectively and US examinations were conducted at all 68 joints. At patient level, associations with clinical composites and US scores were performed using correlations and by analysing patients with predominantly tender (pTender) or swollen joints (pSwollen). At joint level, a PD value ≥ 1 was defined as active synovitis. A generalized linear mixed model was created to assess the predictive value of TJ and SJ for active synovitis after 12 months.

RESULTS

SJC showed better correlations with GS/PD scores (r = 0.37/0.47) than with TJC (PD: r = 0.33), while TJC correlated better with patient reported outcomes (PROMs) like patient global assessment (TJC: r = 0.57; SJC r = 0.39). Patients with pTender showed poorer results for PROMs and disease activity scores than patients with pSwollen, but not for laboratory or US markers of inflammation. Swollen joints showed active synovitis in 35% of cases, while only 16% of tender joints were active according to US. Swelling at baseline better predicted active synovitis at the same joint after 12 months (OR 6.33, p< 0.001) as compared with tenderness (OR 3.58, p< 0.001).

CONCLUSIONS

SJ are more closely linked with US signs of inflammation as compared with TJ in PsA. Joint swelling is a better predictor for signs of US inflammation than tenderness after one year of follow-up.

POS0102 GO ASK YOUR PATIENTS! PSS-QoL REPORTED PERCEPTION OF DRYNESS CORRELATES WITH LACRIMAL AND SALIVARY FLOW IN PRIMARY SJÖGREN’S SYNDROME

Background:

The patient perspective is an essential outcome parameter in the quest for effective therapy in primary Sjögren’s Syndrome (PSS). The EULAR Sjögren’s Syndrome Patient Reported Index (ESSPRI) is recommended by EULAR to quantify patient’s symptom burden and has been used in several clinical trials. Surprisingly, the patient’s perception of dryness quantified with ESSPRI does not correlate with objective measures of salivary or lacrimal flow.

Objectives:

Thus, we evaluated a newly developed assessment tool-the Primary Sjögren’s Syndrome Quality of Life Questionnaire (PSS-QoL) - for quantifying symptoms of dryness in comparison with the ESSPRI and objective measurements of salivary and lacrimal flow.

Methods:

Data of patients from the PSS registry of the Medical University of Graz fulfilling the 2016 ACR/EULAR classification criteria for PSS were analysed. The patient perspective was analyzed by PSS-QoL, ESSPRI, Xerostomia Inventory (XI) and Ocular Surface Disease Index (OSDI). Sicca signs were measured with Schirmer’s test, unstimulated salivary flow test (USF) and stimulated salivary flow test (SSF). Patients were categorized into groups based on the presence of subjective and/or objective dryness: 1) objective dryness only, 2) subjective dryness only, and 3) both, subjective and objective dryness. ESSDAI (EULAR Sjögren’s Syndrome Disease Activity Index) and EGA (Evaluator Global Assessment, numeric rating scale from 0 to 10) were obtained. In addition, free light chains (FLC) ĸ and λ, rheumatoid factor (RF) IgM and IgA were determined.

Results:

Data from 123 PSS patients were analyzed; 91.9% (n=113) were female, with a mean disease duration of 6.2 (±5.3) years and mean age of 60.1 (±12.4) years. PSS-QoL-dryness revealed significant negative correlations with Schirmer’s test (r=-0.31, p<0.05) and SSF-test (r=-0.39, p<0.01). In contrast, we found no significant correlation between ESSPRI-dryness and any objective dryness test. Lower perceived dryness was associated with higher immunological activity determined by increased levels of IgG, FLC and RF-IgA. Patients with objective signs and subjective symptoms of dryness had higher clinical and immunological disease activity compared to patients with subjective symptoms only (table 1).

Table 1.

Comparison of perceived dryness-groups with clinical parameters

PSS-QoL MouthpPSS-QoL Eyespsubjobj/subjsubjobj/subjEGA1.0 [0-5]2.0 [0-7]<0.051.0 [0-3]2.0 [0-7]<0.05ESSDAI1.0 [0-144.0 [0-15<0.053.0 [0-74.0 [0-15nsESSPRI-pain3.0 [0-9]3.0 [0-10]ns4.0 [1-8]3.0 [0-10]<0.05RF-IgM19.0 [5-524]31.0 [7-417]ns10.0[5-33]26.0[7-524]<0.01FLC-λ15.1 [7.0-68.3]20.1 [2.6-124.0]<0.0113.4 [7.0-54.5]18.7[2.6-124.0]<0.01IgG11.9 [6.5-37.2]16.1 [7.4-33.8]ns12.8 [6.5-20.6]14.8[7.4-37.2]nsC40.2 [0.01-0.41]0.17 [0.00-0.43]<0.010.2 [0.09-0.41]0.18 [0.00-0.43]nsRF-IgA11.0 [1-500]103 [0-500]<0.014.5 [1-465]63 [0-500]<0.01

C4=Complementfactor 4; EGA=Evaluators Global Assessment; ESSDAI=EULAR Sjögren Syndrome Disease Activity Index; ESSPRI=EULAR Sjögren Syndrome Patient Reported Index; FLC-λ=Free light chain Lambda; IgG=Immunoglobulin G; obj/subj=objective and subjective dryness-group; PSS-QoL=Primary Sjögren Syndrome Quality of Life Questionnaire; RF-IgA=rheumatoid factor Immunoglobulin A; RF-IgM=rheumatoid factor Immunoglobulin M; subj=subjective dryness-group.

Conclusion:

Patients’ perception of dryness assessed by PSS-QoL correlates with objective measurements of salivary gland function while ESSPRI-dryness did not. Based on the PSS-QoL and objective measures of dryness two distinct groups of PSS patients could be distinguished, which may have implications in daily practice and future clinical studies.

Disclosure of Interests:

None declared

OP0309 THE ROLE OF IMAGING TO GUIDE INTERVENTIONAL PROCEDURES IN RHEUMATIC AND MUSCULOSKELETAL DISEASES: A SYSTEMATIC LITERATURE REVIEW TO INFORM EULAR RECOMMENDATIONS

Background:

Imaging guidance gives the opportunity to visualize a needle or other instrument when performing interventions on musculoskeletal sites in patients with rheumatic and musculoskeletal diseases (RMDs). Studies assessing the role of imaging guided procedures have been performed, however, no consensus has been made yet about when and which imaging techniques to use for these interventions.

Objectives:

To inform a EULAR taskforce on the current literature on different imaging techniques, procedures and materials to guide interventions on musculoskeletal sites in RMD patients.

Methods:

Prospective and retrospective studies published in English and comparing either palpation or imaging guided interventions in patients with RMDs were included. MEDLINE, EMBASE, the Cochrane Library and Epistemonikos were searched through October 2021. Risk of bias (RoB) was assessed using the Cochrane RoB tool for randomized trials version 2 (ROB2), the RoB tool for Non-Randomized Studies of Interventions (ROBINS-I) and the appraisal tool for cross-sectional studies (AXIS).

Results:

Sixty-six studies, with moderate to high RoB, consisting of 49 randomized controlled trials, three prospective cohort studies and 14 retrospective studies were included.

Fifty-one studies compared one imaging technique against either another imaging technique, or palpation-guided interventions. Most of the studies were on peripheral joints (47/51), while data on joints of the axial skeleton were scare and heterogeneous (4/51). For peripheral joints, ultrasound (US) was the most studied imaging technique (49/51), followed by fluoroscopy (10/51). Results revealed a higher accuracy and safety (including procedural pain) of US or fluoroscopy compared to palpation- guided interventions. Data on other imaging techniques was scarce (computed tomography: n=3, arthroscopy: n=1) and the results heterogeneous. Results of studies comparing different imaging techniques (12/51) did not favor one imaging method over another.

Three studies comparing different materials used for imaging guided interventions were found (e.g. automatic vs manual syringes), showing little evidence for one material being superior to another one.

Fifteen studies were found comparing different imaging guided procedures (e.g. intraarticular vs periarticular injections). Overall, studies indicated an advantage of targeted vs. not targeted interventions (intraarticular vs periarticular or intraepineurial vs extraepineurial injections) concerning pain levels, while the comparison of different puncture sites to inject (e.g. ulnar vs midline carpal tunnel injection) was inconclusive.

Conclusion:

Imaging guidance, especially US, performs favorably for interventions at the peripheral joints compared to palpation-guided interventions, concerning accuracy and safety. Data for the axial skeleton are scarce. Imaging guided targeted interventions may lead to better outcomes than non-targeted interventions.

Disclosure of Interests:

None declared.

Go Ask Your Patients! PSS-QoL Reported Perception of Dryness Correlates With Lacrimal and Salivary Flow in Primary Sjögren's Syndrome

Introduction/Objectives: The patient perspective is an essential outcome parameter in the quest for effective therapy in primary Sjögren's Syndrome (PSS). The EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI) is recommended by EULAR to quantify patient's symptom burden and has been used in several clinical trials. Surprisingly, the patient's perception of dryness quantified with ESSPRI does not correlate with objective measures of salivary or lacrimal flow. Thus, we evaluated a newly developed assessment tool-the Primary Sjögren's Syndrome Quality of Life Questionnaire (PSS-QoL)-for quantifying symptoms of dryness in comparison with the ESSPRI and objective measurements of salivary and lacrimal flow. Methods: Data of patients from the PSS registry of the Medical University of Graz fulfilling the 2016 ACR/EULAR classification criteria for PSS were analyzed. The patient perspective was analyzed by PSS-QoL, ESSPRI, Xerostomia Inventory (XI) and Ocular Surface Disease Index (OSDI). Sicca signs were measured with Schirmer's test, unstimulated salivary flow test (USF) and stimulated salivary flow test (SSF). ESSDAI (EULAR Sjögren's Syndrome Disease Activity Index) and EGA (Evaluator Global Assessment, numeric rating scale from 0 to 10) were obtained. In addition, free light chains (FLC) κ and λ, rheumatoid factor (RF) IgM and IgA were determined. Results: Data from 123 PSS patients were analyzed; 91.9% (n = 113) were female, with a mean disease duration of 6.2 (±5.3) years and mean age of 60.1 (±12.4) years. PSS-QoL-dryness revealed significant negative correlations with Schirmer's test (r = -0.31, p < 0.05) and SSF-test (r = -0.390, p < 0.01). In contrast, we found no significant correlation between ESSPRI-dryness and any objective dryness test. Lower perceived dryness was associated with higher immunological activity determined by increased levels of IgG, FLC and RF-IgA. Whereas patients with only subjective signs of dryness had lower immunological activity. Discussion: Patients' perception of dryness assessed by PSS-QoL correlates with objective measurements of salivary gland function while ESSPRI-dryness did not. Based on the PSS-QoL and objective measures of dryness two distinct groups of PSS patients could be distinguished, which may have implications in daily practice and future clinical studies.

Ultrasound for diagnosis and follow-up of chronic axillary vasculitis in patients with long-standing giant cell arteritis

Aims:

To assess intima-media thickness (IMT) changes measured by ultrasound in axillary arteries of giant cell arteritis (GCA) patients over time and to calculate an ultrasound cut-off value for the diagnosis of chronic axillary artery involvement in patients with longstanding GCA.

Methods:

Ultrasound of both axillary arteries was performed in 109 GCA patients at time of diagnosis and at several follow-up visits and in 40 healthy controls (HCs). IMT determined at the prospective follow-up visit was compared between GCA patients with (axGCA) and without (non-axGCA) vasculitis of axillary arteries at baseline, as well as with HCs. Changes in IMT were depicted. Receiver operating characteristics were performed for cut-off calculations. Inter-/intra-rater agreement was evaluated using stored images and intraclass correlation coefficient (ICC).

Results:

Seventy-three patients were in the axGCA and 36 in the non-axGCA group. Pathological IMT of axillary arteries (axGCA) declined in the first 18 months of treatment by −0.5 mm, (range −2.77 to 0.50), independent of age and gender. Median IMT, after median disease duration of 48 months (16–137), was 0.90 mm (0.46–2.20) in axGCA and 0.60 mm (0.42–1.0) in the non-axGCA group pooled with HCs. An IMT of 0.87 mm was highly specific (specificity 96%, sensitivity 61%) for diagnosis of chronic axGCA. Intra-rater and inter-reader agreement of ultrasound images were good [ICC 0.96–1.0 (three readers) and 0.87, respectively].

Conclusion:

Pathological IMT of the axillary artery declined under treatment. An IMT of 0.87 mm is highly specific for diagnosis of chronic vasculitis of axillary arteries in long-standing GCA patients.

Ultrasound verified enthesophytes are associated with radiographic progression at entheses in psoriatic arthritis

OBJECTIVES

The aim of this prospective study was to examine whether ultrasound or clinical abnormalities at enthesal sites predict radiographic progression at entheses in psoriatic arthritis (PsA).

METHODS

Consecutive PsA patients were included and subjected to clinical and ultrasound assessments at 14 entheses at baseline, 6 and 12 months. Radiographs were performed at 0 and 12 months. By US, we investigated structural (erosions, osteophytes) and inflammatory changes [grey scale (0-32) and power Doppler (0-14, range global ultrasound score 0-140)], and radiographs were evaluated for enthesophytes and erosions (score range 0-56). Multivariate regression models were conducted to identify the possible association of clinical and ultrasound findings with radiographic progression.

RESULTS

We examined 83 patients at baseline, of whom 43 (51.8%) had complete clinical, ultrasound and X-ray data. Twenty-four of 43 patients (55.8%) developed radiographic progression of entheses. These patients were younger (49.6 vs 59.3, P =0.005), had shorter disease duration (9.7 vs 17.9 years, P=0.015) and lower clinical disease activity at 6-months [disease activity in psoriatic arthritis (DAPSA) 6.7 vs 17.0, P=0.018] as compared with patients without progression. Non-progressors had higher ultrasound enthesophyte scores at baseline than progressors (20 vs 15, P<0.05). The multivariate regression analysis revealed that 48.6% of the variance of the X-ray score at 12-months follow-up (RegcoeffB = 0.827, P=0.000) could be explained by the baseline US enthesophyte score.

CONCLUSION

Our data indicate that radiographic progression at entheses is linked with age, disease duration and ultrasound verified enthesophytes at baseline. No other ultrasound parameter predicted radiographic progression at entheses.

Case Report: Extensive Phosphorylation of Interleukin-1 Receptor-Associated Kinase 4 in a Patient With Schnitzler Syndrome

Schnitzler syndrome (SchS) is a rare autoinflammatory disease, characterized by urticarial rash, recurrent fever, osteo-articular pain/arthritis with bone condensation, and monoclonal gammopathy. Diagnosis may be difficult due to overlapping signs with other diseases. Here, we describe the case of a 62-year-old man with SchS, who was initially misdiagnosed with multicentric Castleman disease (MCD). As excessive release of IL-6 is characteristic of MCD, in contrast to IL-1 in SchS, we measured the phosphorylation of intracellular signaling proteins of the respective pathways by flow cytometry. We found a distinct increase of phosphorylated IRAK-4 in our patient's B cells and monocytes while phosphorylation of STAT-3 was low, suggesting predominant IL-1 signaling. In accordance with these results and the classification criteria, we established the diagnosis of SchS instead of MCD and commenced therapy with the IL-1 receptor antagonist anakinra. We observed a rapid remission of signs accompanied by a reduction of phosphorylated IRAK-4 to normal levels. In conclusion, we propose phosphorylated IRAK-4 in B cells and monocytes as a potential marker for diagnosis of SchS and for treatment response to IL-1 blockade.

AB1083 CURRENT PRACTICE AND OPINIONS ON IMAGING-GUIDED INTERVENTIONAL PROCEDURES IN RHEUMATIC AND MUSCULOSKELETAL DISEASES: INTERIM RESULTS OF A MULTINATIONAL MULTIDISCIPLINARY SURVEY TO INFORM EULAR POINTS TO CONSIDER

Background:

maging is widely used for diagnostic purposes in patients with rheumatic and musculoskeletal diseases (RMDs). In recent years, it is increasingly used also to guide interventional procedures. However, the extent of imaging application for this purpose as well as the different technical standards employed across Europe are not known.

Objectives:

To learn how much imaging is used for interventional procedures in RMDs. To explore the technical standards employed in different settings and how important they are rated by users.

Methods:

As part of the work of a multidisciplinary EULAR Task Force to develop recommendations for the use of imaging to guide interventional procedures in patients with RMDs, a survey was developed. The survey explored aspects of different interventional procedures (e.g. joint aspiration/injection) such as the use of imaging guide and the technical standards. Respondents provided also a 0-10 rating of how important they considered the same conditions/items with regard to each procedure. The survey was distributed to: rheumatologists across Europe, USA, Central America, South America, Asia and Pacific Area, HPs across Europe, European and American associations of other specialities (e.g. radiology, anaesthesiology). The survey was launched in December 2019. Interim results after 4 weeks are presented.

Results:

200 responses from 36 countries were collected. The respondents were mainly rheumatologists (90%) (Figure 1). 90% of respondents performed interventional procedures related to RMDs and of these, 76% use imaging guide. Ultrasonography (US) is the most commonly used technique (96%) followed by X-ray/fluoroscopy (13%). Among respondents using imaging guide, 60% received training on both imaging and imaging-guided procedures, 20% only on imaging and 16% no training. 49% of respondents perform the whole procedure using direct image guidance, 21% use imaging to find the appropriate anatomical landmark and then perform the procedure blindly. Air and contrast agent to control needle placement are rarely used (≤20%). Respondents provided also a rating (0-10) of how important they considered different technical conditions/items for each procedure and an estimate on a Likert scale of how often they used them for each of the procedures (Figure 1 shows an example). In most cases respondents use always/most of the times the conditions/items that they considered important. Discrepancies were mainly due to barriers at their own center.

Conclusion:

Imaging, mainly US, is widely used to guide interventional procedures. However, training is not homogeneous and the use of imaging guide as well as technical conditions are based on the operator’s opinion/experience. This survey will inform the EULAR points to consider for the use of imaging to guide interventional procedures in patients with RMDs.

Table 1.

Characteristics of respondents (n=200) N

N%Age≤ 30381931 –35562836 – 39502540 - 493316.5≥ 502311.5GenderFemale8944.5Male11155.5Specialty/PositionRheumatology18090Radiology115Physical medicine and rehabilitation31.5Pediatrics42Non-clinical researcher31.5Health professionals31.5Other31.5

Disclosure of Interests:

Francesco Carubbi Speakers bureau: Francesco Carubbi received speaker honoraria from Abbvie and Celgene outside this work., Philipp Bosch: None declared, Pedro M Machado Consultant of: PMM: Abbvie, Celgene, Janssen, Lilly, MSD, Novartis, Pfizer, Roche and UCB, Speakers bureau: PMM: Abbvie, BMS, Lilly, MSD, Novartis, Pfizer, Roche and UCB, Carlo Alberto Scirè: None declared, Alessia Alunno: None declared, Xenofon Baraliakos Grant/research support from: Grant/research support from: AbbVie, BMS, Celgene, Chugai, Merck, Novartis, Pfizer, UCB and Werfen, Consultant of: AbbVie, BMS, Celgene, Chugai, Merck, Novartis, Pfizer, UCB and Werfen, Speakers bureau: AbbVie, BMS, Celgene, Chugai, Merck, Novartis, Pfizer, UCB and Werfen, Christian Dejaco: None declared

AB0746 EVALUATING TENDER AND SWOLLEN JOINTS FOR THE ASSESSMENT OF INFLAMMATORY PAIN IN PSORIATIC ARTHRITIS USING ULTRASOUND

Background:

Tender and Swollen Joint Counts (TJC, SJC) are items of disease activity scores in rheumatoid arthritis (RA) and psoriatic arthritis (PsA). Recent studies suggest that TJC do not adequately reflect ongoing inflammation in RA when using Ultrasound (US) as a reference standard, and that pain might be due to other, non-inflammatory causes.1, 2In PsA, the role of tenderness and swelling of joints for reflecting active inflammation has not been well studied so far.

Objectives:

To evaluate tender (TJ) and swollen joints (SJ) for the assessment of inflammation in PsA.

Methods:

We performed a prospective study on 83 PsA patients undergoing clinical and ultrasound examinations at two study visits scheduled 12 months apart. Tenderness and swelling were assessed for 68 and 66 joints respectively and US examinations, including grey scale (GS) and power doppler (PD) were conducted at all 68 joints. GS- (range 0-204) und PD sum scores (0-204) were calculated. At patient level, correlations were performed between TJC, SJC and clinical or US values. At joint level a GS value≥1 and/or PD value≥1 was defined as active synovitis, which was compared to whether a joint was tender, swollen or both. A generalized linear mixed model was created to assess the predictive value of TJ and SJ for active synovitis after 12 months, taking into consideration the joint site.

Results:

At baseline the median TJC and SJC for 83 patients was 4 (range 0-59) and 1 (0-20), respectively and the median GSS- and PD sum score was 16 (3-56) and 3 (0-31) respectively. SJC correlated with the GSS sum score (r= 0.37, p=0.004) and PD sum score (r =0.47, p<0.001), while TJC only correlated with PD sum score (r=0.33, p=0.01). TJC correlated better than SJC with patient reported outcomes like patient global assessment (TJC: r=0.57, p<0.001; SJC r=0.39, p=0.002) and health assessment questionnaire (TJC: r=0.50, p<0.001, SJC no significant correlation). Swollen joints (with or without tenderness) showed active synovitis (GSS≥1 and/or PD≥1) in 67.6% of cases, while tender joints (with or without swelling) showed signs of US activation in only 34.5%. A joint that was considered swollen at baseline was more likely to express active synovitis after 12 months (OR: 4.3, 97.5 CI: 2.9-6.2), compared to a joint that was either tender or swollen at baseline (OR: 2.8, 97.5 CI: 2.1-3.5).

Conclusion:

SJC are more closely linked with US signs of inflammation as compared to TJC in PsA. While swelling of a joint predicts US inflammation after a year, the information whether the joint is additionally tender or not, gives no additional predictive information.

References:

[1]Hammer HB, Michelsen B, Sexton J, et al. Swollen, but not tender joints, are independently associated with ultrasound synovitis: results from a longitudinal observational study of patients with established rheumatoid arthritis.Ann Rheum Dis2019;78:1179-85.

[2]Hammer HB, Michelsen B, Provan SA, et al. Tender joint count may not reflect inflammatory activity in established rheumatoid arthritis patients - results from a longitudinal study.Arthritis Care Res (Hoboken) 2018

Disclosure of Interests:

None declared

Evaluating current definitions of low disease activity in psoriatic arthritis using ultrasound

OBJECTIVE

To evaluate low disease activity (LDA) cut-offs in psoriatic arthritis (PsA) using ultrasound.

METHODS

Eighty-three PsA patients underwent clinical and ultrasound examinations at two visits. LDA was assessed using the Disease Activity index for Psoriatic Arthritis (DAPSA ⩽ 14), the Psoriatic ArthritiS Disease Activity Score (PASDAS ⩽ 3.2), the Composite Psoriatic Disease Activity Index ⩽ 4, the DAS28-CRP ⩽ 2.8 and the minimal disease activity criteria. Ultrasound was performed at 68 joints and 14 entheses. Minimal ultrasound disease activity (MUDA-j/e) was defined as a Power Doppler score ⩽ 1, respectively at joints, paratendinous tissue, tendons and entheses. A global ultrasound score was calculated by summing Grey Scale and Power Doppler information (GUIS-j/e).

RESULTS

LDA was present in 33.7-65.0% at baseline and in 44.3-80.6% at follow-up, depending on the criteria used. MUDA-j/e was observed in 16.9% at baseline and in 30% at follow-up. GUIS-j/e was significantly higher in patients with moderate/high disease activity vs LDA according to DAPSA and PASDAS at baseline and DAPSA, PASDAS, Composite Psoriatic Disease Activity Index and minimal disease activity at follow-up. Patients in moderate/high disease activity had MUDA-j/e in 8.1-21.4% at baseline and in 8.3-20.0% at follow-up, depending on the applied clinical composite. MUDA-j/e patients with moderate/high disease activity had higher levels of pain and pain-related items than those with LDA.

CONCLUSION

The LDA cut-offs of DAPSA, PASDAS, Composite Psoriatic Disease Activity Index, minimal disease activity, but not DAS28-CRP are capable of distinguishing between high and low ultrasound activity. Pain and pain-related items are the main reason why PsA patients without signs of ultrasound inflammation are classified with higher disease activity.

The accuracy of diagnostic Imaging techniques in patients with a suspected Fracture-related Infection (IFI) trial: study protocol for a prospective multicenter cohort study

INTRODUCTION

The optimal diagnostic imaging strategy for fracture-related infection (FRI) remains to be established. In this prospective study, the three commonly used advanced imaging techniques for diagnosing FRI will be compared. Primary endpoints are (1) determining the overall diagnostic performances of white blood cell (WBC) scintigraphy, fluorodeoxyglucose positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) in patients with suspected FRI and (2) establishing the most accurate imaging strategy for diagnosing FRI.

METHODS AND ANALYSIS

This study is a non-randomised, partially blinded, prospective cohort study involving two level 1 trauma centres in The Netherlands. All adult patients who require advanced medical imaging for suspected FRI are eligible for inclusion. Patients will undergo all three investigational imaging procedures (WBC scintigraphy, FDG-PET and MRI) within a time frame of 14 days after inclusion. The reference standard will be the result of at least five intraoperative sampled microbiology cultures, or, in case of no surgery, the clinical presence or absence of infection at 1 year follow-up. Initially, the results of all three imaging modalities will be available to the treating team as per local protocol. At a later time point, all scans will be centrally reassessed by nuclear medicine physicians and radiologists who are blinded for the identity of the patients and their clinical outcome. The discriminative ability of the imaging modalities will be quantified by several measures of diagnostic accuracy.

ETHICS AND DISSEMINATION

Approval of the study by the Institutional Review Board has been obtained prior to the start of this study. The results of this trial will be disseminated by publication of peer-reviewed manuscripts, presentation in abstract form at scientific meetings and data sharing with other investigators through academically established means.

TRIAL REGISTRATION NUMBER

The IFI trial is registered in the Netherlands Trial Register (NTR7490).

German Mobile Apps in Rheumatology: Review and Analysis Using the Mobile Application Rating Scale (MARS)

Background

Chronic rheumatic diseases need long-term treatment and professional supervision. Mobile apps promise to improve the lives of patients and physicians. In routine practice, however, rheumatology apps are largely unknown and little is known about their quality and safety.

Objective

The aim of this study was to provide an overview of mobile rheumatology apps currently available in German app stores, evaluate app quality using the Mobile Application Rating Scale (MARS), and compile brief, ready-to-use descriptions for patients and rheumatologists.

Methods

The German App Store and Google Play store were systematically searched to identify German rheumatology mobile apps for patient and physician use. MARS was used to independently assess app quality by 8 physicians, 4 using Android and 4 using iOS smartphones. Apps were randomly assigned so that 4 apps were rated by all raters and the remaining apps were rated by two Android and two iOS users. Furthermore, brief app descriptions including app developers, app categories, and features were compiled to inform potential users and developers.

Results

In total, 128 and 63 apps were identified in the German Google Play and App Store, respectively. After removing duplicates and only including apps that were available in both stores, 28 apps remained. Sixteen apps met the inclusion criteria, which were (1) German language, (2) availability in both app stores, (3) targeting patients or physicians as users, and (4) clearly including rheumatology or rheumatic diseases as subject matter. Exclusion criteria were (1) congress apps and (2) company apps with advertisements. Nine apps addressed patients and 7 apps addressed physicians. No clinical studies to support the effectiveness and safety of apps could be found. Pharmaceutical companies were the main developers of two apps. Rheuma Auszeit was the only app mainly developed by a patient organization. This app had the highest overall MARS score (4.19/5). Three out of 9 patient apps featured validated questionnaires. The median overall MARS score was 3.85/5, ranging from 2.81/5 to 4.19/5. One patient-targeted and one physician-targeted app had MARS scores >4/5. No significant rater gender or platform (iOS/Android) differences could be observed. The overall correlation between app store ratings and MARS scores was low and inconsistent between platforms.

Conclusions

To our knowledge, this is the first study that systematically identified and evaluated mobile apps in rheumatology for patients and physicians available in German app stores. We found a lack of supporting clinical studies, use of validated questionnaires, and involvement of academic developers. Overall app quality was heterogeneous. To create high-quality apps, closer cooperation led by patients and physicians is vital.

Diagnostic accuracy of serum inflammatory markers in late fracture-related infection: a systematic review and meta-analysis

AIMS

To assess the diagnostic value of C-reactive protein (CRP), leucocyte count (LC), and erythrocyte sedimentation rate (ESR) in late fracture-related infection (FRI).

MATERIALS AND METHODS

PubMed, Embase, and Cochrane databases were searched focusing on the diagnostic value of CRP, LC, and ESR in late FRI. Sensitivity and specificity combinations were extracted for each marker. Average estimates were obtained using bivariate mixed effects models.

RESULTS

A total of 8284 articles were identified but only six were suitable for inclusion. Sensitivity of CRP ranged from 60.0% to 100.0% and specificity from 34.3% to 85.7% in all publications considered. Five articles were pooled for meta-analysis, showing a sensitivity and specificity of 77.0% and 67.9%, respectively. For LC, this was 22.9% to 72.6%, and 73.5% to 85.7%, respectively, in five articles. Four articles were pooled for meta-analysis, resulting in a 51.7% sensitivity and 67.1% specificity. For ESR, sensitivity and specificity ranged from 37.1% to 100.0% and 59.0% to 85.0%, respectively, in five articles. Three articles were pooled in meta-analysis, showing a 45.1% sensitivity and 79.3% specificity. Four articles analyzed the value of combined inflammatory markers, reporting an increased diagnostic accuracy. These results could not be pooled due to heterogeneity.

CONCLUSION

The serum inflammatory markers CRP, LC, and ESR are insufficiently accurate to diagnose late FRI, but they may be used as a suggestive sign in its diagnosis.

203 Genome Modifications by Sleeping Beauty Transposition and CRISPR/Cas9 to Improve Cow Milk Composition for Human Consumption

Genome manipulation of cattle represents a powerful tool to increase the nutritional value and reduce allergenicity of cow milk for human consumption. This could be accomplished by improving the amount of polyunsaturated fatty acids (ω-3 and ω-6) and simultaneously abolishing β-lactoglobulin (BLG), a potent allergen for predisposed humans. The aim of this study was to introduce the sequence for a desaturase construct (mFAT-2, from C. elegans), which is able to catalyse the synthesis of ω-3 and ω-6 fatty acids, into the bovine genome by Sleeping Beauty (SB) transposition, and simultaneously knocking out the bovine β-lactoglubulin gene using CRISPR/Cas9 system. The sgRNA (AAGTGCCTCCTGCTTGCCC) targeted to BLG exon 1 was synthesised as an oligo linker and cloned into the px459-Cas9. The mutation activity of the designed sgRNA at the target locus was determined by T7 endonuclease assay I (T7EI) mismatch detection assay. Briefly, bovine fetal fibroblasts (BFF) were seeded at 0.5 × 105 cells per well of a 24-well plate in triplicate, when the cells reached 80% confluence (12–24 h), cultures were transfected with 1 μg of px459-Cas9::BLG plasmid co-expressing Cas9 and sgRNA using polyethylenimine reagent (PEI; 3 ng μL−1). After 3 days of puromycin selection, genomic DNA from transfected cells were extracted and the sequence of interest was PCR-amplified and digested by T7EI restriction enzyme. Digestion products showed a mutation efficiency at the target locus of 29%. Subsequently, we chemically cotransfected 0.5 × 105 BFF with 0.5 μg of knockout vector (px459-Cas9::BLG) and 0.5 μg of SB plasmids (carrying mFAT-2 cDNA for mammary gland-specific expression) using 3 ng μL−1 PEI in triplicate. At 48 h post-transfection, cell cultures were subjected to 3 days of puromycin and 21 days of neomycin selection. PCR analysis of antibiotic resistant colonies revealed the presence of mFAT-2 transgene in almost 70% of the analysed cells lines. Genotyping of BLG exon 1 was performed by direct sequencing of PCR amplicons using primers flanking the target site. Despite the appreciable gene mutation activity of the sgRNA sequence previously determined by T7EI assay (29%), none of the cell lines analysed showed modification in the BLG target locus. We speculate that the SB vector might have disrupted the activity of targeting vector. We are currently performing additional experiments to accomplish gene addition (mFAT) and gene knockout (BGL) in one step using these highly efficient and precise transgenic tools. Genetically modified cells will be used as nuclear donor to produce transgenic cows by somatic cells nuclear transfer. The financial support of CONICET, UNRC and FONCYT is gratefully acknowledged.

Transfection of bovine fetal fibroblast with polyethylenimine (PEI) nanoparticles: effect of particle size and presence of fetal bovine serum on transgene delivery and cytotoxicity

The development of efficient transfection protocols for livestock cells is crucial for implementation of cell-based transgenic methods to produce genetically modified animals. We synthetized fully deacylated linear 22, 87 and 217 kDa polyethylenimine (PEI) nanoparticles and compared their transfection efficiency and cytotoxicity to commercial branched 25 kDa PEI and linear 58 kDa poly(allylamine) hydrochloride. We studied the effect of PEI size and presence of serum on transfection efficiency on primary cultures of bovine fetal fibroblasts and established cells lines (HEK 293 and Hep G2). We found that transfection efficiency was affected mainly by polymer/pDNA ratio and DNA concentration and in less extent by PEI MW. In bovine fibroblast, preincubation of PEI nanoparticles with fetal bovine serum (FBS) greatly increased percentage of cells expressing the transgene (up to 82%) while significantly decreased the polymer cytotoxic effect. 87 and 217 kDa PEI rendered the highest transfection rates in HEK 293 and Hep G2 cell lines (>50% transfected cells) with minimal cell toxicity. In conclusion, our results indicate that fully deacylated PEI of 87 and 217 kDa are useful DNA vehicles for non-viral transfection of primary cultures of bovine fetal fibroblast and HEK 293 and Hep G2 cell lines.

Simultaneous Measurement of Fluorescence, Conversion and Physical/mechanical Properties for Monitoring Bulk and Localized Photopolymerization Reactions in Heterogeneous Systems

An FT-NIR spectrometer, rheometer and fluorescence spectrophotometer were coupled for the real-time monitoring of polymerization reactions, allowing the simultaneous tracking of polymerization kinetics, storage modulus as well as fluorescence. In this study, a methacrylate functionalized dansyl chromophore (DANSMA) was synthesized and two different nanogels were made from urethane dimethacrylate and isobornyl methacrylate. Two series of resin formulations were prepared using the DANSMA probe, ethoxylated bisphenol A dimethacrylate as the matrix monomer, Irgacure® 651 as the initiator and the dispersed, monomer-swollen nanogels to give clear UV-curable resins. Placement of the fluorescent probe either throughout the resin or linked into the nanogel before its dispersion in the matrix provides a tool to study how the nanogel structure affects local network development by means of fluorescence from the DANSMA probe. We demonstrate the potential of this new technique using a composite as the two phase system (resin and polymerizable nanogel) including a dansyl derivative as a polymerizable probe to follow the reactions that are taking places in both phases.

242 HIGHLY EFFICIENT SLEEPING BEAUTY TRANSPOSON-MEDIATED TRANSGENESIS IN BOVINE FETAL FIBROBLASTS

Active transposon-mediated transgenesis is an emerging tool for basic and applied research in livestock. We have demonstrated the effectiveness of a helper-independent piggyBac transposon (pGENIE-3) for gene transfer into the genome of bovine cells (Alessio et al. 2014 Reprod. Domest. Anim. 49, 8). Here, we extend our previous research by examining the suitability of a Sleeping Beauty (SB) transposon-based methodology to deliver transgenes into the genome of bovine fetal fibroblasts (BFF), and the ability of these cells to support in vitro embryo development upon somatic cell nuclear transfer (SCNT). In a first experiment, BFF were chemically cotransfected (JetPRIME®, Polyplus-transfection, Illkirch, France) with a helper plasmid (pCMV-SB100X), which carries an expression cassette for the SB transposase, and the donor vector (pT2/Venus/RMCE) harboring an expression cassette for a fluorescent protein (Venus) flanked by the SB inverted terminal repeats (ITR). Three different ratios of helper and donor plasmids were studied: 1 : 2, 1 : 1 and 2 : 1. After 15 days of culture, the number of fluorescent colonies was counted on an inverted microscope. When vectors were used at ratios of 1 : 1 and 2 : 1, a 78-fold and 88-fold increase (P ≤ 0.05) in the number of fluorescent colonies compared with that in the no-transposase control were calculated. In a second experiment, BFF were chemically cotransfected with the helper vector pCMV-SB100X, and 2 donor transposons: pT2/Venus/RMCE and pT2/SV40-Neo. The former harbors a neo resistance cassette framed by SB ITRs. Different ratios of helper:donors (1 : 1 : 1, 2 : 1 : 1 and 2 : 0.5 : 0.5) were studied, and each ratio compared with a no-transposase control. After 15 days of antibiotic selection, the number of G418-resistant colonies was determined. Every time a functional SB transposase vector was included, the number of fluorescent and G418-resistant colonies was markedly higher compared with that in the respective control without transposase (P ≤ 0.001). Interestingly, all G418-resistant colonies expressed Venus. Molecular characterisation of genomic insertions in 6 monoclonal cell lines was performed by PCR and splinkerette PCR. PCR analysis confirmed presence of the Venus transgene in all cell lines. Splinkerette PCR results revealed at least 15 transposase-catalyzed genomic insertions of the transgene. Individual cells from a polyclonal SB transgenic fibroblast culture were used as nuclear donors to produce zona-free SCNT embryos. Of the reconstructed embryos, 33% reached blastocyst stage and about half of them expressed Venus. In conclusion, SB transposase is able to actively transpose monomeric copies of transgenes into the genome of bovine cells, which can be reprogrammed upon nuclear transfer to generate morphologically normal embryos expressing the transgene of interest.

Lipid peroxidation affects red blood cells membrane properties in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune, chronic inflammatory, non-organ specific disease with an important morbimortality affecting several organs and systems. Oxidative stress is a well documented mechanism of red blood cells (RBC) mechanical impairment. Free radicals could produced, through lipid peroxidation, physical and chemical alterations in the cellular membrane properties modifying its composition, packing and lipid distribution on the membrane erythrocyte. The aim of the present work is to study the lipid peroxidation in the RBC membrane in SLE patients (n = 42) affecting so far the lipid membrane fluidity and erythrocyte deformability in comparison with healthy controls (n = 52). Malonildialdehyde (MDA) is a subrogate assessing lipidic peroxidation, rigidity index estimating erythrocyte deformability and the anisotropy coefficient estimating lipid membrane fluidity were used. Our results show that MDA values are increased, while erythrocyte deformability and membrane fluidity are significantly decreased in erythrocyte membrane from SLE patients in comparison with normal controls. The association of thiobarbituric acid reactive substances (TBARS) with membrane lipid fluidity and erythrocyte deformability confirms that the damage of membrane properties is produced by lipid peroxidation.

356 SLEEPING BEAUTY TRANSGENESIS IN CATTLE

Transposon-mediated transgenesis is a well-established tool for genome modification in small animal models. However, translation of this active transgenic method to large animals warrants further investigations. Here, the Sleeping Beauty (SB) transposon system was assessed for stable gene transfer into the cattle genome. The transposon plasmids encoded a ubiquitously active CAGGS promoter-driven Venus reporter and a lens-specific α A-crystallin promoter driven tdTomato fluorophore, respectively. The helper plasmid carried the hyperactive SB100x transposase variant. In total, 50 in vitro-derived zygotes were co-injected (Garrels et al. 2011 PLoS ONE 6; Ivics et al. 2014 Nat. Protoc. 9) and cultured up to blastocyst stage (Day 8). Two blastocysts were Venus-positive and were transferred to synchronized heifers, resulting in one pregnancy. The resulting calf was normally developed and vital; however, it died shortly after cesarean section due to spontaneous bleeding from an undetected aneurism. Phenotypic analysis suggested that the calf was indeed double-transgenic, showing widespread expression of Venus and lens-specific expression of tdTomato. Genotyping and molecular analyses confirmed the integration of both reporter transposons and the faithful promoter-dependent expression patterns. Subdermal tissue of an ear biopsy was used to culture fibroblasts, which were employed in somatic cell nuclear transfer experiments. In total, 39 embryos were reconstructed, of which 34 underwent cleavage, and at the end of culture 12 morulas and 12 blastocysts were obtained. Ten of the blastocysts were Venus positive, and embryo transfer of Venus-positive blastocysts is planned. In summary, we showed that the cytoplasmic injection of SB components is a highly efficient method for transgenesis in cattle. Due to the modular composition of SB plasmids, even double transgenic cattle can be generated in a one-step procedure. Importantly, the SB-catalyzed integration seems to favour transcriptionally permissive loci in the genome, resulting in faithful and robust promoter-dependent expression of the transgenes. The transposon constructs carry heterospecific loxP sites, which will be instrumental for targeted insertion of functional transgenes by Cre recombinase-mediated cassette exchange.Financial support of DFG (Ku 1586/3-1), UNRC, CONICET and Agencia Nacional de Promoción Científica y Tecnológica de la Argentina (ANPCyT) is gratefully acknowledged.

357 EARLY FETAL DEVELOPMENT OF NUCLEAR TRANSFER BOVINE EMBRYOS GENERATED FROM FIBROBLASTS GENETICALLY MODIFIED BY piggyBac TRANSPOSITION

Transposon-mediated transgenesis is a well-established tool for genome manipulation in small animal models. However, translation of this active transgenesis method to the large animal setting requires further investigation. We have previously demonstrated that a helper-independent piggyBac (PB) transposon system can efficiently transpose transgenes into the bovine genome [Alessio et al. 2014 Reprod. Domest. Anim. 49 (Suppl. 1), 8]. The aims of the current study were a) to investigate the effectiveness of a hyperactive version of the PB transposase, and b) to determine the ability of the genetically modified cells to support early embryo and fetal development upon somatic cell nuclear transfer (SCNT). Bovine fetal fibroblasts (BFF) were chemically transfected with either pmGENIE-3 (a helper-independent PB transposon conferring genes for hygromycin resistance and enhanced green fluorescent protein (EGFP); Urschitz et al. 2010 PNAS USA 107, 8117–8122), pmhyGENIE-3 (carrying an hyperactive version of the PB transposase; Marh et al. 2012 PNAS USA 109, 19 184–19 189), or pmGENIE-3/Δ PB (a control plasmid lacking a functional PB transposase). Upon transfection, cell cultures were subjected to 14 days of hygromycin selection. Antibiotic-resistant and EGFP+ colonies were counted and data analysed by ANOVA and Tukey's test. For SCNT, pmhyGENIE-3 and pmGENIE-3 polyclonal cell lines were selected by FACS and individual cells used as nuclear donors. Day 7 blastocysts were nonsurgically transferred to synchronized recipients. Conceptuses were recovered by Day 35 of gestation, observed under fluorescence excitation, and genotyped. The mean number of colonies in pmhyGENIE-3 group was significantly higher than those in pmGENIE-3 and the control group (324.0 ± 17.8 v. 100.0 ± 16.1 and 2.8 ± 0.8 respectively, n = 4–7; P < 0.05). The hyperactive transposase increased transgene integration efficiency 3.24 times compared with the conventional PB transposase. The SCNT and early fetal development data are summarised in Table 1. Phenotypic analysis revealed that both transgenic fetuses and the extraembryonic membranes expressed EGFP with no macroscopic evidence of variegated transgene expression. Molecular analysis by PCR confirmed that both fetuses carried the transposon DNA. Here, we demonstrate that a hyperactive version of the PB transposase is more active in bovine cells than the conventional PB transposase. In addition, SCNT embryos generated from genetically modified cells by the pGENIE transposon system can progress to early stages of fetal development. Table 1.SCNT and early fetal development of bovine fibroblasts transposed with piggyBac1 The financial support of UNRC, CONICET and ANPCyT from Argentina is gratefully acknowledged.

331 OPTIMIZATION OF BRANCHED 25kDa POLYETHYLENIMINE FOR EFFICIENT GENE DELIVERY IN BOVINE FETAL FIBROBLASTS

Cost-effective, highly efficient, and noncytotoxic transfection of bovine fetal fibroblasts (BFF) has proven difficult to achieve by regular chemical and physical methods. The aims of this study were to evaluate transient transfection efficiency and toxicity of commercially available branched 25 kDa polyethylenimine (25 kDa PEI, Sigma-Aldrich, St. Louis, MO, USA) and to optimize the transfection conditions leading to high percentages of PEI-transfected fibroblasts with minimum cytotoxic effects. Bovine fetal fibroblast (BFF) cells were seeded a day before transfection in 24-well plates at a density of 3 × 104 cells per well in DMEM with antibiotics and 10% SFB. When 70 to 90% confluence was reached, cells were washed with PBS and incubated in DMEM without antibiotics or SFB. For the transfection-mix preparation, increasing amounts of plasmidic DNA (pZsGreen1; 2 to 6 µg) were added to 50 µL of DMEM without antibiotics or SFB, incubated for 5 min at room temperature, and complexed with 0.5 to 4 µg of PEI (from 1 mg mL–1 solution) in 50 µL of PBS for 10 min. This transfection mix was added to the cell cultures and, 2 h later, 500 µL of DMEM with antibiotics and 10% SFB was added to each well. Detection of green fluorescent protein (GFP) expression by flow cytometry (reported as percentage of green fluorescent cells) was performed 48 h after transfection. Results were analysed by ANOVA and Tukey test and expressed as mean ± SEM (P < 0.05). We found no significant difference between the percentage of GFP-positive cells transfected with 1 or 2 µg of 25 kDa PEI at 2 µg of DNA/well (15.2 ± 1.3 v. 16.9 ± 0.9%, respectively; P > 0.05), whereas cells transfected with 1 or 2 µg of low-molecular-weight PEI (2 kDa) showed extremely low transfection efficiencies. Increasing the DNA load up to 6 µg significantly enhanced cell transfection (3.5- and 6-fold comparing 2 µg v. 4 µg and 6 µg of DNA, respectively; P < 0.05) at 1 and 2 µg of 25 kDa PEI/well. In order to evaluate the cytotoxic effect of PEI, cell viability was determined using the MTT assay in 96-well plates (cells/well), with each condition scaled down to replicate the effect of 2 kDa or 25 kDa PEI in a 24-well plate. The MTT results (expressed as % of the control) indicated that PEI became cytotoxic at concentrations equivalent to 2 and 4 µg/well (54.7 ± 3.4 and 18.5 ± 5.7, respectively), whereas 1 µg/well produced a slight detrimental effect on cell viability (90.0 ± 2.6). No evidence of cytotoxicity was observed when the BFF were incubated with 0.5 µg/well of 25 kDa PEI and 1 or 2 µg/well of 2 kDa PEI. To study if a combination of low- and high-molecular-weight PEI could improve transfection efficiency and reduce toxicity, we tested a mixture (1 : 1) of 2 kDa and 25 kDa PEI. Even though the 1 : 1 mixture was less cytotoxic, the efficiency of gene delivery was not improved. We conclude that, under our experimental conditions, the highest percentage of GFP-expressing cells with good viability was obtained when 1 µg of 25 kDa PEI was added per well. Therefore, branched 25 kDa PEI transfection represents an efficient, simple, and cost-effective alternative for gene delivery in bovine fibroblast cells in culture.

46 MEGANUCLEASE I-SceI ENHANCES STABLE TRANSGENE INTEGRATION IN CULTURED BOVINE FETAL FIBROBLASTS

Production of genetically modified large animals through somatic cell nuclear transfer (SCNT) requires genetic manipulation of cultured cells, which are subsequently used as nuclear donors to generate a transgenic animal. Stable transgene integration into the donor cell genome is an inefficient process that involves integration of transgenes in randomly occurring DNA double-strand breaks. Therefore, our objective was to evaluate transient and stable transfection in cultured bovine fetal fibroblasts (BFF) using a transgenic strategy based on the simultaneous presence of a meganuclease (I-SceI) and a transgene flanked by restriction sites for I-SceI. Bovine fetal fibroblasts (2.63 × 104 cells cm–2 in 24-well plates) were co-transfected with a plasmid vector (pBSII-I-SceI-ZsGreen1-Neo) carrying expression cassettes for ZsGreen1 (fluorescent protein) and neomycin resistance flanked by restriction sites for I-SceI along with an expression plasmid for I-SceI (pCBASce). As controls, BFF were co-transfected with pBSII-I-SceI-ZsGreen1-Neo plus a plasmid that lacks the I-SceI expression cassette (pCBA). Lipofectamine 2000 (Invitrogen) was used as the transfection reagent as per manufacturer’s instructions. Two different relationships of vector pBSII-I-SceI-ZsGreen1-Neo to pCBASce or pCBA (control) were tested: 1 : 1 and 1 : 3 (total amount of plasmid DNA per well was 500 ng). Transient transfection was evaluated by flow cytometry and reported as percentage of green fluorescent cells 72 h post-co-transfection. Stable integration of transgene sequences was assessed 21 days after co-transfection by determining the number of fluorescent cell colonies (FCC) that developed in selective media (DMEM + 250 µg mL–1 of G418). Data were analyzed by ANOVA and Tukey test and expressed as mean ± standard error of the mean. Flow cytometric analysis at 72 h post-transfection showed no statistical differences between the proportions of fluorescent cells in cultures co-transfected with pCBASce compared with those transfected with the control plasmid. The number of FCC developed from cultures co-transfected with pBSII-I-SceI-ZsGreen1-Neo plus pCBASce at a 1 : 1 ratio was 6.4-fold higher compared with those observed in the control group at the same ratio (8.00 ± 2.16 v. 1.25 ± 0.62 colonies; P < 0.05). However, there was no difference in the number of FCC formed at a plasmid ratio of 1 : 3 between the treatment (3.75 ± 1.03 colonies) and the control (2.70 ± 1.35 colonies; P > 0.05). Several transgenic BFF cell lines were generated by subculturing individual colonies. Polymerase chain reaction and Southern blotting confirmed that antibiotic-resistant and phenotypically positive colonies had integrated the ZsGreen1 transgene. Western blot analysis using an anti-HA antibody revealed a band of the expected size (30 kDa) in cells transfected with pCBASce. We conclude that I-SceI transgenesis significantly increases the functional integration of plasmid DNA into the bovine fibroblast genome as has been reported in embryos of other vertebrates, up to now by unknown mechanisms. This transgenic strategy should facilitate stable transfection of bovine fibroblasts to generate genetically modified animals though SCNT.