Leaf anatomy affects optical properties and enhances photosynthetic performance under oblique light

Photosynthesis under oblique illumination has not been studied extensively despite being the prevailing light regime under natural conditions. We studied how photosynthetic rate (An) is affected by the geometrical arrangement between leaf lamina and light rays, in conjunction with key anatomical features; studied plant species selected based on the absence (homobaric) or the occurrence of bundle sheath extensions (BSEs; heterobaric) and the arrangement of these structures, that is, parallel (monocots) or reticulated (dicots). The direction of light ray affected leaf absorptance (Abs) and An; both were maximal when the angle of incidence of light on leaf surface (polar angle, θ) was 90°. For any lower θ, both Abs and An were higher when the angle between the leaf axis and the light rays (azimuthal angle, φ) was zero. The dependence of Abs and An from φ was only evident in monocots and, especially, in heterobaric compared to homobaric leaves. In some species, An was substantially higher than predicted from calculated photon flux density of oblique light. The occurrence of BSEs, especially in monocots, significantly alters leaf optical properties, resulting in more efficient photosynthesis under oblique illumination conditions.

POS0122 CENTRAL NERVOUS SYSTEM DEMYELINATING SYNDROMES IN SYSTEMIC LUPUS ERYTHEMATOSUS: RESULTS FROM “ATTIKON” LUPUS COHORT

Background

Central nervous system (CNS) demyelinating syndromes that occur in the context of SLE may represent a manifestation of neuropsychiatric lupus, or an overlap of SLE and multiple sclerosis (MS). The differential diagnosis between the two entities has important clinical implications, because the therapeutic management differs between the two conditions.

Objectives

To characterize CNS demyelinating syndromes in a large SLE cohort as neuropsychiatric SLE or SLE-MS overlap, using a multidisciplinary approach and existing diagnostic (MS) and classification criteria (SLE)

Methods

Patients from the “Attikon” lupus cohort (n=707) were evaluated for demyelinating syndromes. Clinical, laboratory and neuroimaging data were recorded for each patient. Following multidisciplinary evaluation and application of criteria, the demyelinating syndrome was attributed to either SLE or MS. Patients with transverse myelitis were not included in this study.

Results

We identified 26 patients with demyelinating syndromes (3.7%) with mean age at diagnosis 46.9 (SD 12.3) years and median disease duration at last follow-up 60 (IQR 52) months. Of them, 12 were diagnosed as primary SLE-demyelination (46.2%) and 14 as overlap SLE-MS (53.8%). The two groups did not differ with respect to rheumatologic and neurologic manifestations, or serologic findings (ANA, dsDNA, C3/C4, aPL, ENA). SLE patients with demyelination manifested mild extra-CNS disease mainly involving joints and skin, while severe non-CNS manifestations were rare. However, patients with SLE-demyelination were less likely to have elevated IgG index (OR 0.055 95% CI: 0.008-0.40) and positive oligoclonal bands (OR 0.09 95% CI: 0.014-0.56). SLE patients with primary demyelinating syndrome were less likely to exhibit brain lesions in the spinal cord, infratentorial, periventricular and juxtacortical regions. A single brain region was affected in 9 SLE-demyelination patients (75%), while all MS-SLE patients had multiple affected brain regions. MS-SLE overlap was associated with increased likelihood of neurologic relapses (OR 18.2, 95% CI: 1.76-188), while SLE-demyelination patients were less likely to exhibit neurological deficits (EDSS>0) at last follow-up visit (50% vs. 78.6%in SLE-MS, respectively).

Conclusion

Demyelination in the context of SLE follows a more benign course compared to a frank SLE-MS overlap. Prolongation of follow-up will ascertain whether SLE-demyelination patients evolve to MS, or this is a bona fide NPSLE syndrome.

Disclosure of Interests

None declared

POS0210 A PREDOMINANT NON-SPECIFIC INTERSTITIAL PNEUMONIA PATTERN AND ABERRANT TRANSCRIPTOMIC NEUTROPHIL-MEDIATED IMMUNITY CHARACTERIZE A CONTEMPORARY RA-ILD COHORT

Background

Lung involvement is the most common extra-articular manifestation. Rheumatoid arthritis related interstitial lung disease (RA-ILD) comprises a heterogeneous group of parenchymal lung disorders classified by distinct clinical, pathologic, and radiographic features. According to the current paradigm, circulating immune complexes and aberrant neutrophil extracellular trap formation (NETosis) contribute to disease pathogenesis.

Objectives

To characterize the pattern of lung disease in “Attikon” RA-ILD cohort and develop insights about the pathophysiologic mechanisms via whole blood RNA sequencing.

Methods

Retrospective and prospective study to identify clinical, laboratory and radiologic characteristics of patients with RA and pulmonary manifestations in the “Attikon” RA-ILD cohort. Changes in pulmonary function tests (PFTs), pattern of lung involvement (chest HRCT), disease activity (DAS28-ESR) and incidence of complications and comorbidities, were prospectively analyzed during the one-year follow-up period. Peripheral blood was collected in a subset of RA-ILD (n=11) and control RA patients (n=9) for RNA isolation and RNA sequencing. The gene expression profile of RA-ILD was inferred through differential gene expression analysis, followed by pathway and enrichment analyses.

Results

114 patients with RA-ILD were included [67% female, mean (SD) age at diagnosis 71.5 (9) years, 58% seropositive]. Non-specific interstitial pneumonia (NSIP) was the radiologic pattern most frequently observed (52%), followed by usual interstitial pneumonia (UIP) (24%). RA was diagnosed after ILD in 40% of patients. Mean (SD) FVC and DLCOsb at baseline was 80.5 (19.2) and 55.4 (19.5), respectively. Disease activity was lower in seropositive compared to seronegative both at baseline and at 1-year follow-up (p=0.025). PFTs at 12 months from baseline had been stabilized. Respiratory infections were observed in 17.6% of patients during the first year of follow-up, more common in the NSIP vs UIP group (p=0.01), possibly due to the higher doses of glucocorticoids in NSIP patients. RNA-sequencing analysis revealed a distinct gene expression profile in RA-ILD, characterized by the activation of type I interferon response, neutrophil activation and degranulation, and CCR1 chemokine interactions.

Conclusion

NSIP is the most frequent pattern of ILD in this RA-ILD cohort, carrying a higher risk for respiratory infections probably related to higher doses of glucocorticoid used. Myeloid cells’ migration via CCR1 and the formation of pro-inflammatory and pro-fibrotic NETs by activated neutrophils may contribute to RA-ILD pathogenesis.

References

[1]Y Dai et al, Rheumatoid arthritis–associated interstitial lung disease: an overview of epidemiology, pathogenesis and management Clin Rheumatol. 2021 Apr;40(4):1211-1220

[2]X Zulma Yunt et al, Lung Disease in Rheumatoid Arthritis Rheum Dis Clin North Am. 2015 May;41(2):225-36

Table 1.

Patients’ characteristics with RA-ILD in Attikon cohort

Patients CharacteristicsN=114Mean age71.5±9Female: Male76/38Smoking (current/ex)23/43Arterial hypertension71Diabetes mellitus32Dyslipidemia52COPD/BA17Thyroid disease30Latent TB17Seropositive66Diagnosis RA before ILD34Diagnosis RA after ILD45NSIP59UIP27Mixed NSIP-UIP5Organizing Pneumonia (OP)17Nodules21

Disclosure of Interests

None declared

POS0365 RELAPSES ARE COMMON ΙΝ SEVERE HEMATOLOGICAL SLE: REAL-LIFE EXPERIENCE FROM THE “ATTIKON” LUPUS COHORT

Background

Hematological manifestations are common in systemic lupus erythematosus (SLE), and are thought to result from immune-mediated peripheral cell destruction or bone marrow failure(1,2).

Objectives

To assess the clinical characteristics and outcomes of severe hematological disease in a large cohort of lupus patients.

Methods

Retrospective analysis of the “Attikon” lupus cohort (over 800 patients total) (3) for the identification of patients with a history of severe hematological manifestation. The latter were defined as: thrombocytopenia with a platelet count <30.000/mm3, hemolytic anemia with an hemoglobin <8 g/dL, neutropenia with less than 500 neutrophils/mm3, history of thrombotic microangiopathy (TMA) or macrophage activation syndrome (MAS). Treatments and long-term outcomes (relapses, mortality) were recorded.

Results

Among 300 patients with hematologic manifestations, 40 patients had severe disease. Most of them were women (75%). Mean age at SLE diagnosis was 41,1 years and mean disease duration at diagnosis of cytopenia was 3.8 years. Hematologic manifestation preceded SLE diagnosis in 13 patients (32,5%).

Autoimmune thrombocytopenia was the most common (57,5%), followed by hemolytic anemia (17.5%), TMA (12.5%) and Evans syndrome (7,5%). All patients received glucocorticoids (GC). Rituximab (15%) and cyclophosphamide (12,5%) were the most frequently used GC-sparing agents during the first episode. Nine patients (22,5%) received intravenous immunoglobulin (IVIg). Relapse occurred in 23 patients (57,5%), most of which (N=17, 73,9%) were treated with GC alone or in combination with IVIg or plasma exchange at initial presentation, without the use of GC-sparing agents. Most of the flares (60,8%) were severe. No deaths were observed.

Conclusion

Hematological disease in SLE is treatment-responsive. GC remain the mainstay of treatment, but the high relapse rates underscore the need for more efficient GC-sparing agents.

References

[1]Fayyaz A, Igoe A, Kurien BT, Danda D, James JA, Stafford HA, Scofield RH. Haematological manifestations of lupus. Lupus Sci Med. 2015 Mar 3;2(1):e000078.

[2]Hepburn AL, Narat S, Mason JC. The management of peripheral blood cytopenias in systemic lupus erythematosus. Rheumatology (Oxford). 2010 Dec;49(12):2243-54

[3]Nikolopoulos D, Kostopoulou M, Pieta A, Karageorgas T, Tseronis D, Chavatza K, Flouda S, Rapsomaniki P, Banos A, Kremasmenou E, Tzavara V, Katsimbri P, Fanouriakis A, Boumpas DT. Evolving phenotype of systemic lupus erythematosus in Caucasians: low incidence of lupus nephritis, high burden of neuropsychiatric disease and increased rates of late-onset lupus in the ‘Attikon’ cohort. Lupus. 2020 Apr;29(5):514-522.

Table 1.

Characteristics of patients with hematological manifestations

Age at diagnosis, mean (years)41,1Women N(%)30(75)Mean disease duration at cytopenia diagnosis (years)3,8Thrombocytopenia, N=23, (mean platelet count,/mm3)11682Hemolytic anemia,N=7 (mean Hb,g/dL)6,75Neutropenia N=1,(mean neutrophil count)450Evans syndrome, N=3 (mean Hb, g, mean platelet count)7 /46600TMA,N=5, (mean platelet count)8750MAS, N=1Immunosuppressive treatment at initial presentationAzathioprine (N,%) 4(10) Corticosteroids (N,%) 40 (100) Cyclophosphamide (N,%) 5(12,5) IgIV (N,%) 9 (22,5) Mycophenolate mofetil (N,%) 2(5) Rituximab (N,%) 6(15)Relapse N(%)23(57,5)Severe relapse (N,%)14(60,8)Non responder to corticosteroids/IgIV (N,%)1(2,5)

Disclosure of Interests

None declared

POS0368 EARLY (3 MONTHS) IMPROVEMENT IN PHYSICIAN GLOBAL ASSESSMENT OF DISEASE ACTIVITY PREDICTS LONG-TERM RETENTION OF BELIMUMAB TREATMENT IN SLE: A MULTICENTRE OBSERVATIONAL STUDY OF 184 PATIENTS

Background

Belimumab has been introduced in the management of SLE for more than 10 years, however long-term efficacy and safety data are still limited and mostly derive from the extended phase of randomized clinical trials.

Objectives

To evaluate the long-term survival of belimumab treatment, reasons for treatment cessation and associated predictors in routine care setting.

Methods

Multicentre observational study of adult SLE patients who were treated with belimumab according to physician discretion and in line with the EULAR recommendations. Disease activity (Physician Global Assessment [PGA]: scale 0-3; SLE disease activity index-2000 [S2K]), flares (SELENA-SLEDAI Flare Index), organ damage (SLICC damage index [SDI]), co-administered treatments and dosage, adverse events and causes of belimumab discontinuation were monitored prospectively at 3–6-month intervals. Cox-regression analysis was performed to identify factors associated with reduced drug survival.

Results

A total 184 patients treated with belimumab for at least 3 months were included (women 95.6%; mean ± SD age 48.8 ± 13.4 years; disease duration 9.2 ± 11.3 years). Baseline S2K and PGA were 7.5 ± 3.0 and 1.64 ± 0.42, respectively, both demonstrating significant improvement at 6 months (4.5 ± 3.5 and 1.02 ± 0.69, respectively; p<0.001) and 12 months (3.5 ± 3.1 and 0.68 ± 0.55, respectively; p<0.001). Of patients receiving glucocorticoids at onset, 49.0% tapered the dose and 17.6% completely withdrew them. After a median (interquartile range) follow-up of 15.1 (16.9) months, 44.0% of patients discontinued belimumab due to suboptimal efficacy as judged by the treating physician (28.3%), adverse events (including infections) (9.8%) or other causes (e.g., pregnancy, patient decision). Accordingly, efficacy-related drug survival rates at 1 and 2 years were 70% and 61%, respectively, with corresponding safety-related survival rates of 94% and 87%, respectively. Baseline factors associated with belimumab discontinuation due to suboptimal efficacy included PGA >1.50 (hazard ratio [HR] 3.66; 95% confidence interval [95% CI] 1.14–11.73; p=0.029) and severe (RA-like) arthritis (HR 2.56; 95% CI 1.16–5.68; p=0.020) but not disease duration, use of glucocorticoids, active serology or organ damage. Notably, patients with early (3 months) improvement (i.e., any decrease in PGA) showed significantly lower risk for treatment cessation (HR 0.38; 95% CI 0.22–0.67; p=0.001) (Figure 1) and this effect was independent of the initial PGA level. Baseline use of hydroxychloroquine was associated with prolonged safety-related belimumab survival (HR 0.32; 95% CI 0.12–0.88; p=0.028).

Figure 1.

Efficacy-related survival of belimumab according to improvement or not of PGA at 3 months since treatment initiation.

Conclusion

In real-life setting, about 28% of SLE patients discontinue belimumab due to suboptimal treatment response per physician judgement, especially those with moderate-to-high activity and severe arthritis. Improvement in PGA at 3 months predicts long-term drug maintenance, therefore suggesting its value for patient monitoring. Our data confirm the very good tolerability of belimumab and identify hydroxychloroquine co-administration as a predictor for prolonged safety-related drug survival.

Acknowledgements

The study was partly funded by the Greek Rheumatology Society and the Greek Association of Professional Rheumatologists (ERE-EPERE) and by Pfizer Global Medical Grants

Disclosure of Interests

Myrto Nikoloudaki: None declared, Dionysis Nikolopoulos: None declared, SOFIA KOUTSOVITI: None declared, Irini Flouri: None declared, Noemin Kapsala: None declared, ARGYRO REPA: None declared, PELAGIA KATSIMPRI: None declared, EVANGELOS THEOTIKOS: None declared, Sofia Pitsigavdaki: None declared, Katerina Pateromichelaki: None declared, Anastasios Eskitzis: None declared, ANTONIA ELEZOGLOU: None declared, Prodromos Sidiropoulos: None declared, Antonis Fanouriakis: None declared, Dimitrios Boumpas: None declared, George Bertsias Speakers bureau: GSK, AstraZeneca, Pfizer, SOBI, UCB, Novartis, AENORASIS, Abbvie, Grant/research support from: GSK, Pfizer

POS0461 DISRUPTED HIPPOCAMPAL NEUROGENESIS MEDIATED BY IL-6 AND IL-18 INDUCE NEUROPSYCHIATRIC CHANGES IN MURINE LUPUS

Background

Systemic lupus erythematosus (SLE) frequently affects the nervous system (NPSLE), however, its pathogenesis is only partly understood. We have previously characterized the behavioral phenotype of the NZΒ/W-F1 lupus-prone mouse which recapitulates the NPSLE phenotype exhibiting hippocampal-linked behavior including depressive-like disorder, anxiety and cognitive impairment both at early and late stages of the disease characterized by a profound hippocampal inflammatory response1,2. Defective hippocampal neural stem cell (hNSC) response is associated with cognitive dysfunction, depression and anxiety, all of which represent common neuropsychiatric features of both human and murine SLE.

Objectives

To further investigate the hippocampal neurogenesis in lupus mice and determine its involvement in disease pathogenesis.

Methods

All experiments were performed in female NZW/NZB F1 and C57BL/6 (WT) mice at the age of 3 months (pre-nephritic) and 6 months (nephritic stage) (n=5-8/condition/experiment). Neurogenesis was assessed in sagittal sections of hippocampus by immunohistochemical staining (DCX, Sox2, GFAP, Iba1) and morphological criteria. RNA-sequencing was performed in hippocampal tissue followed by pathway and enrichment analysis. Apoptosis (cleaved-caspase 3) and immune cell infiltration (CD11b, CD45, Ly6G, Ly6C, MHC-II, CD4, CD8, B220, Iba1, CD80, CD86, Argianse-1, iNOS) were assessed by flow-cytometry. Cytokines levels were measured by Legendplex. Ex vivo assays were performed in adult hippocampal neural stem cells extracted by 2-month-old female WT mice.

Results

We identified a profound disruption (~2-fold) of hippocampal neurogenesis (decreased DCX+ cells) both at 3 ad 6 month-old lupus mice together with decreased differentiated cells in both time-points, suggesting that lupus mice exhibit impaired neuronal differentiation. Although the number of the neuronal precursors radial glial-like cells (RGLs) was normal at pre-nephritic stage, lupus mice express increased number of both activated RGLs (Sox2+/GFAP+) and proliferating neuronal progenitors (Sox2+ cells) indicating enhanced self-renewal ability of neural precursors and augmented proliferation. Levels of cleaved-caspase 3 were elevated in lupus hippocampus supporting increased hippocampal apoptosis. Transcriptomic analysis of hippocampal tissue revealed a profound inflammatory response in lupus mice. Flow-cytometry analyses showed a pronounced immune cell trafficking in lupus hippocampus with a myeloid predominant response –involving predominantly the microglia- both at early and late stages of the disease. Multiplex assays revealed elevated levels of IL-6 and IL-18 in lupus hippocampus. Ex vivo exposure of adult hNSCs to IL-6 or IL-18 promoted cell proliferation and induced apoptosis.

Conclusion

The NZB/W-F1 mouse model of SLE exhibits defective neurogenesis due to increased apoptosis, and decreased differentiation of neuronal progenitors. Inflammation in lupus hippocampus results in elevated levels of IL-6 and IL-18 with both cytokines negatively affecting the hNSCs response. IL-6 and IL-18 may induce behavioral changes in NZB/W-F1 lupus mediated by altered neurogenesis and may represent therapeutic targets in NPSLE.

References

[1]Nikolopoulos, D., et al. “THU0223 THE NEUROPSYCHIATRIC PHENOTYPE OF NZB/W LUPUS-PRONE MOUSE MODEL AT PRE-NEPHRITIC AND NEPHRITIC STAGES OF THE DISEASE: MURINE MODEL RECAPITULATES HUMAN DISEASE.” (2020): 334-335. http://dx.doi.org/10.1136/annrheumdis-2020-eular.1807

[2]Nikolopoulos D. et al. “OP0040 HIPPOCAMPAL IMMUNE CELL TRAFFICKING AND A MYELOID PREDOMINANT INFLAMMATORY RESPONSE WITH ENHANCED ANTIGEN PRESENTATION AND DECREASED LEVELS OF NEUROTRANSMITTERS UNDERLY THE NEUROPSYCHIATRIC PHENOTYPE OF THE NZW/NZB MURINE LUPUS MODEL.” (2021): 2021. http://dx.doi.org/10.1136/annrheumdis-2021-eular.3972

Acknowledgements

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 742390)

Disclosure of Interests

None declared.

Dynamic changes in cell wall composition of mature sunflower leaves under distinct water regimes affect photosynthesis

In previous work, we identified that exposure to limited water availability induced changes in cell wall composition of mature Helianthus annuus L. leaves that affected mesophyll conductance to CO2 diffusion (gm). However, it is unclear on which timescale these changes in cell wall composition occurred. Here, we subjected H. annuus to control (i.e. water availability), different levels of short-term water deficit stress (ST), long-term water deficit stress (LT), and long-term water deficit stress followed by gradual recoveries addressed at different timescales (LT-Rec) to evaluate the dynamics of modifications in the main composition of cell wall (cellulose, hemicelluloses, pectins and lignins) affecting photosynthesis. During gradual ST treatments, pectins enhancement was associated with gm decline. However, during LT-Rec, pectins content decreased significantly after only 5 h, while hemicelluloses and lignins amounts changed after 24 h, all being uncoupled from gm. Surprisingly, lignins increased by around 200% compared with control and were related to stomatal conductance to gas diffusion (gs) during LT-Rec. Although we suspect that the accuracy of the protocols to determine cell wall composition should be re-evaluated, we demonstrate for the first time that a highly dynamic cell wall composition turnover differently affects photosynthesis in plants subjected to distinct water regimes.

The Optical Properties of Leaf Structural Elements and Their Contribution to Photosynthetic Performance and Photoprotection

Leaves have evolved to effectively harvest light, and, in parallel, to balance photosynthetic CO2 assimilation with water losses. At times, leaves must operate under light limiting conditions while at other instances (temporally distant or even within seconds), the same leaves must modulate light capture to avoid photoinhibition and achieve a uniform internal light gradient. The light-harvesting capacity and the photosynthetic performance of a given leaf are both determined by the organization and the properties of its structural elements, with some of these having evolved as adaptations to stressful environments. In this respect, the present review focuses on the optical roles of particular leaf structural elements (the light capture module) while integrating their involvement in other important functional modules. Superficial leaf tissues (epidermis including cuticle) and structures (epidermal appendages such as trichomes) play a crucial role against light interception. The epidermis, together with the cuticle, behaves as a reflector, as a selective UV filter and, in some cases, each epidermal cell acts as a lens focusing light to the interior. Non glandular trichomes reflect a considerable part of the solar radiation and absorb mainly in the UV spectral band. Mesophyll photosynthetic tissues and biominerals are involved in the efficient propagation of light within the mesophyll. Bundle sheath extensions and sclereids transfer light to internal layers of the mesophyll, particularly important in thick and compact leaves or in leaves with a flutter habit. All of the aforementioned structural elements have been typically optimized during evolution for multiple functions, thus offering adaptive advantages in challenging environments. Hence, each particular leaf design incorporates suitable optical traits advantageously and cost-effectively with the other fundamental functions of the leaf.

POS0764 EULAR RECOMMENDATION-BASED QUALITY INDICATORS (QIS) FOR SYSTEMIC LUPUS ERYTHEMATOSUS (SLE): ELABORATION, FINAL SET, PERFORMANCE AND INITIAL VALIDATION

Background:

Targets of therapy and quality of care are receiving increased attention in systemic lupus erythematosus (SLE).

Objectives:

To develop Quality Indicators (QIs) for the care of SLE patients based on the EULAR recommendations, and assess their performance.

Methods:

Using the published EULAR recommendations for SLE, we developed 44 candidate QIs. These were independently rated for validity and feasibility by 12 experts, analysed by a modified RAND/UCLA model and further scrutinized based on the scorings and expert opinion. (Fig.1) Adherence to the final set of QIs was tested in a cohort of 220 SLE patients combined with an assessment on its impact on disease outcomes such as flares, hospitalizations and organ damage.

Results:

The panel rated 18 QIs as valid and feasible. These involve diagnosis; disease and damage assessment; monitoring for lupus nephritis and drug toxicity; therapy and targets of therapy; fertility and pregnancy; and adjunct therapy (preventive measures for osteoporosis, vaccination, cardiovascular disease). On average, SLE patients received 54% (95%CI 52–56%) of the indicated care with adherence ranging from 41% for QIs related to monitoring to 88% for treatment-related QIs. Regarding targets of therapy, sustained remission or low disease activity were achieved in 27%, while 94% of patients received low-dose glucocorticoids, and 92% the recommended hydroxychloroquine dose. Dependent upon individual QI tested, adherence for lupus nephritis-related QIs was 88% for receiving appropriate adjunct therapy (ACE inhibitors) to 100% for being treated with the indicated immunosuppressive treatment. In contrast, adherence to QIs related to preventive measures and other adjunct therapies was moderate to low. Notably, patients who were eligible for cardiovascular risk modification, vaccination, and osteoporosis management received lower quality of care (40.5%, 47.7% and 45.5% respectively) while 91.4% had sunscreen protection. In reference to laboratory work-up and monitoring, complete laboratory work-up at diagnosis was performed in 48%, while disease activity and damage, were fully assessed only in 14.1% (in three consecutive visits) and 28.6% (annually) respectively, Similarly, reproductive health and pregnancy counselling adherence rates were modest estimated at 50% and 62% respectively. Higher adherence to the indicated care during follow-up (monitoring QIs) was associated with reduced risk for adverse outcomes during the last year of observation (OR 0.97, 95%CI 0.96-0.99). Patients who achieved sustained remission or LLDAS, exhibited fewer flares (OR=0.15, p-value<0.001) and damage accrual (OR=0.35, p-value<0.001). Of interest, patients who received low-dose of GCs or were appropriately vaccinated, had a lower risk of experiencing a flare (OR=0.23 and 0.46 respectively).

Conclusion:

A set of 18 QIs based on the EULAR recommendations for SLE was developed to be used towards improving care in SLE. Initial real-life data suggest variable degree of adherence with higher adherence resulting in reduced adverse outcomes.

References:

[1]Fanouriakis, et al., 2019 Update of the EULAR recommendations for the management of systemic lupus erythematosus. In Annals of the Rheumatic Diseases (Vol. 78, Issue 6, pp. 736–745). BMJ Publishing Group. https://doi.org/10.1136/annrheumdis-2019-215089.

[2]Nikolopoulos, D., et al., Evolving phenotype of systemic lupus erythematosus in Caucasians: low incidence of lupus nephritis, high burden of neuropsychiatric disease and increased rates of late-onset lupus in the ‘Attikon’ cohort. Lupus, 29(5), 514–522. https://doi.org/10.1177/0961203320908932.

Acknowledgements:

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 742390)

Disclosure of Interests:

None declared

POS0421 COMBINED ANALYSIS OF METABOLIC AND TRANSCRIPTOMIC KIDNEY PROFILES OF NZW/B-F1 MURINE LUPUS UNCOVERS BIOLOGICAL MECHANISMS PRECEDING THE ONSET OF NEPHRITIS

Background:

Metabolic pathways are important regulators of immune differentiation and activation in kidneys. Kidneys directly impact systemic metabolism, circulating metabolite levels, and express intrinsic metabolic activity. The integration of renal metabolomic and transcriptomic profiles may unravel unique gene-metabolite pairs of biological significance in lupus nephritis (LN).

Objectives:

To decipher gene-metabolite signatures at both pre-nephritic and nephritic stages of lupus.

Methods:

Kidneys were isolated and snap-frozen after perfusion from female NZB/NZW-F1 lupus mice at the pre-nephritic (3-month-old) and nephritic (6-month-old exhibiting ≥100 ng/dL of urine protein) stage of lupus (n=6/group). Age-matched female C57BL/6 mice were used as healthy controls. Sample extracts were used for RNA sequencing and 1H-NMR spectroscopy metabolic profiling. DESeq2 was used to identify differentially expressed genes. Univariate analysis was used to reveal metabolic differences characteristic for nephritis.

Results:

Comparative transcriptomic analyses uncovered multiple transcripts related to metabolic pathways: In pre-nephritic kidneys, lipid metabolism, cellular respiration, TCA cycle, amino acid metabolism processes were overrepresented in the upregulated genes while in nephritic kidneys, amino acid metabolism processes were overrepresented among the downregulated genes (Figure 1). 1H-NMR analysis revealed a total of 49 metabolites. Comparison of the metabolic levels of nephritic and pre-nephritic animals revealed that ADP, ATP, NAD+, Taurine and Myo-inositol decreased, while Thr increased significantly. The comparison to corresponding control animals, demonstrated that only myo-inositol increased significantly. Integration of kidney metabolomics and transcriptomics indicated the involvement of processes related to glutathione metabolism, leukocyte trans-endothelial migration and antigen presentation during the established renal disease stage.

Conclusion:

The combined transcriptomics and metabolomics analysis revealed metabolic derangements in lupus-affected kidneys both during subclinical and overt LN. Deregulated tissue-levels of taurine and myo-inositol at the subclinical stage of the disease suggest aberrant renal biochemistry preceding the development of overt LN that may directly impact systemic metabolism and circulating metabolite levels.

Figure 1.

Pathways linked to cell metabolism were overrepresented among 3-month upregulated and 6-month lupus mice (F1) downregulated DEGS (differentially expressed genes) compared to controls (C57BL/6).

Acknowledgements:

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 742390).

Disclosure of Interests:

None declared

POS0759 THE JOURNEY OF PATIENTS FROM FIRST SYMPTOMS TO DIAGNOSIS OF SYSTEMIC LUPUS ERYTHEMATOSUS (SLE): AN OBSERVATIONAL STUDY

Background:

The lack of pathognomonic features poses a considerable challenge in SLE diagnosis. The time from symptom onset to diagnosis has been reported to range from two to six years1.

Objectives:

To document the initial symptoms of the disease and the time lapse until its diagnosis.

Methods:

We examined 438 patients from the “Attikon” SLE cohort2. For diagnosis, we used the classification criteria (ACR, SLICC, EULAR-ACR) or in few cases clinical diagnosis (n=32, 7.3%). Data were collected using patient interviews, in-person clinical visits and medical charts review. Initial symptoms were recorded and determined chronologically using prespecified forms with a list of typical manifestations (skin, joints, renal, nervous system, pleuropulmonary, cardiovascular, anti-phospholipid syndrome) as well as characteristic disease features (Raynaud’s phenomenon, fatigue, fever, sicca symptoms). Questions also included the time between symptom onset and initial physician visit, the time from first medical consultation until first rheumatologist assessment, the time from rheumatologist assessment to SLE definite diagnosis, the number of physicians seen before SLE diagnosis, the specialty of first physician and of diagnosing physician. Information on demographic and clinical characteristics, disease activity and disease damage, was collected both at enrolment and at last follow-up visit.

Results:

88.5% of patients were females, mean (±SD) age at diagnosis was 41.9 years ± 15.4 and disease duration was 6.7 ± 7 years. Most common systems involved were joints (94.5%), skin (73.7%), blood (39.2%) and renal (17.5%). At diagnosis, 9.8% of patients were ANA negative. The most common initial symptoms at disease onset were arthritis/arthralgia (74.4%), followed by fatigue (53.1%) and photosensitive rash (50.9%) (Table 1). Among non-criteria features, Raynaud’s phenomenon was reported by 146 patients (33.3%) prior the diagnosis. The median interval between symptoms onset and the SLE diagnosis was 16 months (IQR 5-60). SLE was diagnosed earlier in ANA-positive than -negative patients [median time 14 months (IQR 5-60) vs 36 months (IQR 10.5-84); P=0.1, t-test]. Approximately half of the patients (52.5%) were diagnosed after 12 months from disease onset with only 15.9% diagnosed within 3 months of symptoms presentation. The median lag time between onset of symptoms and the first medical consultation was 2 months (IQR 1-12). Internists were the most common first consultants (27.8%) followed by orthopedists (15.9%), dermatologists (13.6%) and rheumatologists (13.4%). The median interval between the first medical assessment and first rheumatologist evaluation was 3 months (IQR 0-11.5) while the median time from rheumatologist assessment to definite diagnosis was 0 months (IQR 0-4). SLE patients consulted an average of 3 different physicians before the definite diagnosis, which in 95.8% was established by rheumatologists.

Conclusion:

Approximately 50% of patients were diagnosed with SLE after 12 months from symptom onset with a mean time from symptoms to definite diagnosis almost 4 years. Increasing awareness of internists to SLE and avoidance of strict adherence to ANA as a requirement for diagnosis may improve early diagnosis.

Table 1.

Initial symptoms prior to diagnosis

SymptomsN=438 (%)Duration*(mean months ±SD)Arthralgias326 (74.4)37.5 ±69.4Photosensitive rash223 (50.9)30.6 ±70.2Malar rash168 (38.3)22.6 ±62Alopecia167 (38.1)19.6 ±54.6Ulcers106 (24.2)16.8 ±54.4Fever103 (23.5)9.3 ±43.8Raynaud’s phenomenon146 (33.3)22.3 ±68.5Fatigue233 (53.1)19.7 ±45.7

*Mean time from symptom onset to established diagnosis

References:

[1]Nightingale AL, Davidson JE, Molta CT et al. Lupus Science & Medicine 2017; doi:10.1136/lupus-2016-000172.

[2]D Nikolopoulos et al. Lupus 2020; doi: 10.1177/0961203320908932.

Acknowledgements:

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 742390)

Disclosure of Interests:

None declared

OP0040 HIPPOCAMPAL IMMUNE CELL TRAFFICKING AND A MYELOID PREDOMINANT INFLAMMATORY RESPONSE WITH ENHANCED ANTIGEN PRESENTATION AND DECREASED LEVELS OF NEUROTRANSMITTERS UNDERLY THE NEUROPSYCHIATRIC PHENOTYPE OF THE NZW/NZB MURINE LUPUS MODEL

Background:

Neuropsychiatric events are common in patients with systemic lupus erythematosus (SLE), yet the underlying pathogenesis remains ill-defined, as the access to brain tissue is limited. We have previously shown that NZW/NZB F1 murine lupus model recapitulates the neuropsychiatric lupus phenotype including depressive-like behavior, increased rates of anxiety, cognitive dysfunction and motor disturbances, both at pre-nephritic and nephritic stages of the disease.

Objectives:

To dissect specific regions in the brain, which account for this phenotype and elucidate inflammatory and non-inflammatory mechanisms involved.

Methods:

Four distinct brain regions (hippocampus, amygdala, striatum and pre-frontal cortex) were dissected from brains of female C57BL/6 (WT) and NZW/NZB F1 mice at the age of 3 months (pre-nephritic) and 6 months (nephritic stage) (n=5-8/condition/experiment). Since most of the behavioral phenotype corresponds to the hippocampus, we first examined in depth the hippocampal pathology by bulk RNA sequencing, measurements of neurotransmitters levels via high-performance liquid chromatography (HPLC) and by immunophenotyping via flow cytometry analyses. For comparisons, statistical significance was indicated as a two-sided P<0.05.

Results:

Transcriptomic analysis revealed aberrant immune mediated response in the hippocampus of 6 month-old lupus mice compared to WT. Specifically, inflammatory pathways including both innate and adaptive immune responses, increased cytokine production, increased antigen presentation and immune cell trafficking, along with increased apoptosis and decreased cell proliferation suggest that immune aberrancies may lead to neuronal damage. These aberrancies were present in mice at 3 month-old, yet were progressed with time being more prominent at 6 month of age in lupus hippocampus. The RNA sequencing date were validated by immunophenotyping on lupus hippocampus demonstrating increased reactive GFAP+ astrocytes both at 3 and 6-month old mice. Activated IBA1+ microglia and CD11b+CD45hi CNS myeloid cells were increased only at 6 months of age. Furthermore, increased immune cell infiltration from the periphery including lymphocytes (CD45+CD11b-) mainly T cells (CD4+/CD8+) and monocytes (CD45+CD11b+Ly6G-Ly6C+), was evident only in 6 month-old lupus hippocampus compared to WT. Importantly, microglia cells in lupus hippocampus at 6 but not at 3 month of age, exhibited increased expression of antigen presenting markers including CD80, CD86 and MHC-II indicating that microglia cells may carry out the antigen presentation process seen in transcriptomic data. Low levels of serotonin and noradrenaline were observed at both 3 and 6 months of age in lupus mice; these aberrancies were mainly attributed to decreased serotonin synthesis as evidenced by intact serotonin metabolism (no differences were observed at its metabolite: 5-hydroxyindoleacetic acid). Analysis of the remaining regions of the brain combined with studies of metabolic activities of various brain regions by PET-CT scanning is in progress.

Conclusion:

Immune cell trafficking from the periphery combined with marked inflammatory response in the hippocampus underlie the neuropsychiatric phenotype in NZW/B murine lupus. Our data indicate increased expression of activated myeloid cells -including microglia- in the hippocampus of lupus mice culminating in increased antigen presentation and decreased neurotransmitter levels.

References:

[1]Nikolopoulos, D., et al. “THU0223 THE NEUROPSYCHIATRIC PHENOTYPE OF NZB/W LUPUS-PRONE MOUSE MODEL AT PRE-NEPHRITIC AND NEPHRITIC STAGES OF THE DISEASE: MURINE MODEL RECAPITULATES HUMAN DISEASE.” (2020): 334-335.

Acknowledgements:

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 742390)

Disclosure of Interests:

None declared

POS0757 SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) DIAGNOSED DURING HOSPITALIZATION: CLINICAL PHENOTYPE AND PERFORMANCE OF THE SLE RISK PROBABILITY INDEX (SLERPI)

Background:

Systemic Lupus Erythematosus (SLE) can first present with severe or critical disease leading to hospitalization. Prompt recognition of the disease in hospitalized patients may lead to early institution of treatment and improve outcomes. We have recently developed a clinician-friendly algorithm for SLE diagnosis based on classical clinical and serological SLE features [SLE Risk Probability Index (SLERPI)]1.

Objectives:

To determine the clinical phenotype of SLE patients first diagnosed during hospitalization, the interval between hospitalization and SLE diagnosis and the potential impact of SLERPI on early diagnosis.

Methods:

Mixed prospective (from June 2020 to January 2021) and retrospective study of SLE patients from “Attikon” cohort (n=820)2. Clinical phenotype was divided into 10 core domains (neuropsychiatric, thrombosis, nephritis, serosal, haematologic, pulmonary, cardiovascular, gastrointestinal, skin-joints, other). Chart review and patient interview was performed to assess the lag time between 1) the onset of symptoms and 2) the hospitalization and the final diagnosis. Demographic and clinical characteristics, SLERPI and SLICC damage index were recorded for each patient at the time of diagnosis. SLE diagnosis was based on at least one of the three existing classification criteria.

Results:

Out of 820 SLE patients, 202 (24.6%) diagnosed during hospitalization were included. Among them, 185 patients (91.5%) were hospitalized because of a lupus related feature, while in the remaining 17 SLE patients, hospitalization was due to non-lupus related manifestations. The most common lupus-related clinical phenotype leading to hospital admission was neuropsychiatric lupus (n=51, 25.2%) with cerebrovascular events constituting the dominant clinical syndrome (n=8/51). Thrombotic events (n=32, 15.8%), mainly pulmonary embolism (n=20/32), cytopenias (n=32, 15.8%), lupus nephritis (n=30, 14.8%), skin-joint disease (n=26, 12.8%) and serositis (n=24, 11.8%) were also common as dominant manifestations. Pulmonary disease (n=16, 7.9%), heart disease (n= 4, 1.9%) and gastrointestinal disease (n=2, 0.9%) were less common. On admission, 11.3% of patients (n=23) had symptoms from at least 2 clinical domains as defined. Most patients (93.5%) had multisystem disease while only 6.5% had organ-dominant disease. Early diagnosis (within 3 months from hospitalization) was established in 86.6% while 27 patients had their SLE diagnosis more than 3 months from hospitalization. The mean lag time between the hospitalization and the diagnosis was approximately 14 months (SD 19.9). Overall, the mean interval between the onset of symptoms and the diagnosis was 48.2 months (SD 73.2). Importantly, a SLERPI >7 (suggesting probable SLE) at hospitalization was present in 92.5% of SLE patients with delayed diagnosis.

Conclusion:

One out of four SLE patients first present with moderate to severe disease necessitating hospitalization, while in approximately 15% of such patients, diagnosis is initially missed. Application of the SLERPI may facilitate early SLE diagnosis.

References:

[1]Adamichou C et al. Ann Rheum Dis. 2021; DOI: 10.1136/annrheumdis-2020-219069.

[2]D Nikolopoulos et al. Lupus 2020; doi: 10.1177/0961203320908932.

Acknowledgements:

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 742390)

Disclosure of Interests:

None declared

Cell wall composition and thickness affect mesophyll conductance to CO2 diffusion in Helianthus annuus under water deprivation

Water deprivation affects photosynthesis, leaf anatomy, and cell wall composition. Although the former effects have been widely studied, little is known regarding those changes in cell wall major (cellulose, hemicelluloses, pectin, and lignin) and minor (cell wall-bound phenolics) compounds in plants acclimated to short- and long-term water deprivation and during recovery. In particular, how these cell wall changes impact anatomy and/or photosynthesis, specifically mesophyll conductance to CO2 diffusion (gm), has been scarcely studied. To induce changes in photosynthesis, cell wall composition and anatomy, Helianthus annuus plants were studied under five conditions: (i) control (i.e. without stress) (CL); (ii) long-term water deficit stress (LT); (iii) long-term water deficit stress with recovery (LT-Rec); (iv) short-term water deficit stress (ST); and (v) short-term water deficit stress with recovery (ST-Rec), resulting in a wide photosynthetic range (from 3.80 ± 1.05 μmol CO2 m-2 s-1 to 24.53 ± 0.42 μmol CO2 m-2 s-1). Short- and long-term water deprivation and recovery induced distinctive responses of the examined traits, evidencing a cell wall dynamic turnover during plants acclimation to each condition. In particular, we demonstrated for the first time how gm correlated negatively with lignin and cell wall-bound phenolics and how the (cellulose+hemicelloses)/pectin ratio was linked to cell wall thickness (Tcw) variations.

New insights into the functions of carbon-calcium inclusions in plants

Carbon-calcium inclusions (CCaI) either as calcium oxalate crystals (CaOx) or amorphous calcium carbonate cystoliths are spread among most photosynthetic organisms. They represent dynamic structures with a significant construction cost and their appearance during evolution indicates an ancient origin. Both types of inclusions share some similar functional characteristics providing adaptive advantages such as the regulation of Ca levels, and the release of CO₂ and water molecules upon decomposition. The latter seems to be essential under drought conditions and explains the intense occurrence of these structures in plants thriving in dry climates. It seems, however, that for plants CaOx may represent a more prevalent storage system compared with CaCO₃ due to the multifunctionality of oxalate. This compound participates in a number of important soil biogeochemical processes, creates endosymbiosis with beneficial bacteria and provides tolerance against a combination of abiotic (nutrient deprivation, metal toxicity) and biotic (pathogens, herbivores) stress factors. We suggest a re-evaluation of the roles of these fascinating plant structures under a new and holistic approach that could enhance our understanding of carbon sequestration at the whole plant level and provide future perspectives.

THU0223 THE NEUROPSYCHIATRIC PHENOTYPE OF NZB/W LUPUS-PRONE MOUSE MODEL AT PRE-NEPHRITIC AND NEPHRITIC STAGES OF THE DISEASE: MURINE MODEL RECAPITULATES HUMAN DISEASE

Background:

The pathogenesis of neuropsychiatric lupus (NPSLE) remains ill-defined due to limited access to tissue and the diversity and complexity of clinical manifestations with most evidence deriving from animal studies in MLR/lpr lupus-prone mouse.

Objectives:

To phenotype and characterize the neuropsychiatric disease in New Zealand Black/White (NZΒ/W) F1 strain; a spontaneous lupus prone mouse which is characterized by systemic autoimmunity.

Methods:

Mice were tested in a comprehensive behavioral test battery to assess possible effects on general depressive-like disorders, anxiety, cognitive function and motor performance/coordination. The following tests were conducted in the same order for all subjects (All females, NZB/W strain n=13 and C57BL/6 n=14) at 3 and 6 months of age: Open field, Novel object recognition (NOR), Novel object location (NOL), Elevated plus maze (EPM), Rotarod, Tail suspension test (TST), Prepulse inhibition (PPI), and Sucrose preference test (SPT). For comparisons, statistical significance was indicated as a two-sided P<0.05.

Results:

NZB/W mice at 3 months and 6 months of age exhibit depressive-like disorder as assessed by SPT and TST (P <0.05 and <0.0001, respectively). Anxiety-like phenotype was evident in lupus-prone mice at both time points based on EPM test (Graph 1). Open-field test revealed decreased locomotor activity and rotarod (Graph 2) showed impaired motor coordination in 3 month-old and 6 month-old NZB/W mice (P<0.001 and <0.01, respectively). NZB/W mice exhibit cognitive dysfunction at 3 and 6 months of age based on NOR test (P<0.05). No differences in cognitive function was observed between the two groups (P=0.11). Prepulse inhibition test revealed decreased sensorimotor gating in 3 month-old NZB/W mice, a difference not reaching statistical significance (P=.078). It was not possible to interpret correctly the PPI at second time point (6 months of age) due to age-related hearing loss in B6 at 6 month-old. NZB/W become more anxious over the course of the disease as assessed by EPM (3 mo. versus 6 mo. P<0.001, paired t-test, Graph 1).

Conclusion:

The NZB/W lupus-prone strain exhibit depressive-like behavior, anxiety, cognitive impairment and motor disturbances both at early and late stages of the disease. This polygenic murine model may be more suitable for investigating the autoimmunity-mediated neuroinflammation in human SLE.

Disclosure of Interests: :

None declared

FRI0543 BIRTH REGISTRY OF WOMEN WITH SYSTEMATIC LUPUS ERYTHEMATOSUSAND COURSE OF THE DISEASE DURING FIRST YEARS POST-PARTUM-THE GREEK EXPERIENCE

Background:

Pregnancy in women with SLE Systematic Lupus Erythematosus (SLE) has been related with adverse events both in the mother and the foetus.1Many studies have reported relapse of the disease during the pregnancy and post-labour, while others have not confirmed this finding.2To this end, most of these results originate from retrospective studies with patients of diverge ethnicities.

Objectives:

To record the Greek experience with pregnancies in mothers with SLE and their outcomes, as well as the course of the disease during first year post labor.

Methods:

This is a prospective, multicentre, observation study lasting three years. Women diagnosed with SLE who became pregnant consented to be monitored by their treating Rheumatologist. A structured questionnaire is used for monitoring at the beginning of pregnancy (positive pregnancy test) and at least every 3 months thereafter, depending on the course of the disease and pregnancy, until one year after childbirth.

Results:

A total 64 women and 81 pregnancies were recorded (1.27 pregnancies per patient). Patient’s age at conception was 32.8 ± 5.9 years (mean ± standard deviation). Thirteen patients (20.3%) had past history of nephritis. Regarding pregnancy outcomes, 62 (76.5%) pregnancies ended in live births, miscarriages during 1st, 2ndand 3rdtrimester occurred in 13 (16%). Six pregnancies were lost to followup. Prematurity occurred in 28 live births (45.1% in total), 26-32w (3.2%), 32-36w (22.5%), <37w (19.3%). No cases of preeclampsia occurred. Mean age of birth36.9 weeksand mean birth weight2750gr.The majority (72.5%) of deliveries were performed by caesarean section. In terms of disease activity, most of the women had mild disease at conception, (SLEDAI-2K: 2.67±2.69) that declined during 1st/2ndpregnancy trimester (SLEDAI-2K:1.91±2.09, 1.70±2.22)) but increased during the 1stand 2ndtrimester post labor (SLEDAI-2K: 2.47±4.29 and 2.52±3.2).

Conclusion:

This is the first Greek inception cohort with prospective monitoring of pregnant SLE patients. Adverse outcomes occur with prematurity being the most frequent. In our cohort disease activity tends to increase during 1stand 2ndtrimester post-labor without serious relapses. Vigilant monitoring during pregnancy and post-labour is advised.

References:

[1] Bundhun PK, Soogund MZ, Huang F. Impact of systemic lupus erythematosus on maternal and fetal outcomes following pregnancy: A meta-analysis of studies published between years 2001-2016. J Autoimmun 2017;79:17-27. [https://doi. org/10.1016/j.jaut.2017.02.009] [PMID: 28256367]

[2] Wei S, Lai K, Yang Z, Zeng K. Systemic lupus erythematosus and risk of preterm birth: a systematic review and meta-analysis of observational studies. Lupus 2017;26:563-71. [https://doi. org/10.1177/0961203316686704] [PMID: 28121241]

Acknowledgments:

Hellenic Rheumatology Association

Disclosure of Interests:

Stella Ntali: None declared, Lina Pantazi: None declared, Kyriaki Boki: None declared, Dionysis Nikolopoulos: None declared, Antonis Fanouriakis: None declared, Despoina Dimopoulou: None declared, Ioannis Kallitsakis Grant/research support from: MSD, Speakers bureau: Genesis pharma, Bristol-Myers Squibb, CHARALAMPOS PAPAGORAS: None declared, Vasiliki Dania: None declared, Evgenia Emmanouilidou: None declared, George Bertsias Grant/research support from: GSK, Consultant of: Novartis

FRI0170 THERAPEUTIC ΤARGETS AND QUALITY INDICATORS IN SYSTEMIC LUPUS ERYTHEMATOSUS (SLE), DEFINED ACCORDING TO THE 2019 UPDATE OF THE EULAR RECOMMENDATIONS: DATA FROM THE “ATTIKON“ LUPUS COHORT

Background:

Targets of therapy and quality of care are receiving increased attention in the management of SLE, as outlined in the 2019 update of the EULAR recommendations for SLE treatment.

Objectives:

To assess compliance with quality indicators and attainment of treatment targets, according to recent EULAR recommendations, in the SLE cohort of “Attikon” Rheumatology Unit.

Methods:

100 consecutive SLE patients followed for at least one year were. A 30 item Quality Indicator Set (QIS) was developed, according to the 2019 EULAR recommendations for SLE, to include laboratory tests for diagnosis and monitoring, evaluation of disease activity and damage using validated indices, use of patient-reported outcomes, counselling for women’s health and reproduction issues, attainment of targets of therapy [remission or low disease activity state (LLDAS) with low-dose glucocorticoids (GC, ≤7.5mg/day prednizone) and hydroxychloroquine (HCQ dose≤5mg/kg/day)], prevention of disease flares and prevention and management of co-morbidities. Chart review and patient interview was performed to assess the degree of compliance with each item of the QIS and achievement of treatment targets.

Results:

Disease activity was monitored by means of validated indices in 31% and antiphospholipid antibody testing during the first 6 months from diagnosis was performed in 58.8% of patients. Sustained remission (defined as remission of a sustained period of 12 months) or LLDAS was achieved by only 3% and 22% respectively; in contrast, other targets of therapy, such as ≤1 minor flares during last year, were achieved by 85% (43% had complete absence of flares), with 90.2% of patients receiving low-dose GC and 81.8% corrected HCQ dose. Fertility and pregnancy counselling were offered in 40% (12/30 eligible women) and 63.3% (19/30) of patients, respectively, while 65.4% had a Pap Test and only 3 of 32 eligible patients had received the HPV vaccine. Annual lipid status was assessed in 43% and counselling for smoking cessation in 44.6%. Flu vaccination was performed in 77%, while pneumococcal (including both of the pneumococcal vaccines) and herpes-zoster vaccination, were given in 32.7% and 2% (1/44 eligible patients) respectively.

Conclusion:

Our real-life data suggest low vaccination rates (excluding flu) and suboptimal management of cardiovascular risk factors in lupus patients. While the majority of patients received the suggested doses of GC and HCQ, only one quarter of patients achieved remission or LLDAS. There is an unmet need for new therapies in SLE to improve therapy targets.

References:

[1]Arora S, Sequeira W, Yazdany J, Jolly M, “Does Systemic Lupus Erythematosus Care Provided in a Lupus Clinic Result in Higher Quality of Care Than That Provided in a General Rheumatology Clinic?”, Arthritis Care Res. 2018 Dec;70(12):1771-1777. doi: 10.1002/acr.23569. Epub 2018 Nov 10.

Disclosure of Interests:

KATERINA HAVATZA: None declared, KONSTANTINA TOGIA: None declared, Sofia Flouda: None declared, Antigoni Pieta: None declared, Ourania Gioti: None declared, Dionysis Nikolopoulos: None declared, Noemin Kapsala: None declared, Aliki Ntourou: None declared, Panagiota Rapsomaniki: None declared, Thaleia Gerogianni: None declared, Dimitrios Tseronis: None declared, Michail Aggelakos: None declared, Theofanis Karageorgas: None declared, PELAGIA KATSIMPRI: None declared, George Bertsias Grant/research support from: GSK, Consultant of: Novartis, Konstantinos Thomas: None declared, DIMITRIOS BOUMPAS Grant/research support from: Unrestricted grant support from various pharmaceutical companies, Antonis Fanouriakis Paid instructor for: Paid instructor for Enorasis, Amgen, Speakers bureau: Paid speaker for Roche, Genesis Pharma, Mylan

THU0245 PENALIZED REGRESSION ANALYSIS IDENTIFIES CRITERIA AND NON-CRITERIA FEATURES THAT MAY INCREASE THE ACCURACY OF EXISTING SETS OF CRITERIA FOR CLASSIFYING SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)

Background:

The ACR-1997, SLICC-2012 and EULAR/ACR-2019 classification criteria have high sensitivity and specificity for SLE, yet they classify non-overlapping groups of patients suggesting that they can be supplemented with additional features to improve their diagnostic performance.

Objectives:

To identify criteria and non-criteria manifestations that are significantly associated with SLE in clinical practice and can be used to complement the existing sets of classification criteria.

Methods:

Individual items from all three classification criteria (ACR-1997, SLICC-2012, EULAR/ACR-2019) and non-criteria features were analyzed in a randomly selected sample of 800 adults diagnosed with SLE or control rheumatologic diseases (1:1 ratio). The classification performance of each set of criteria was analyzed in combination with complementary features; multivariable least absolute shrinkage and selection operator (LASSO) logistic regression was performed for feature selection. We calculated the diagnostic odds ratio (DOR) of the criteria and the additional features retained in each model.

Results:

Τhe EULAR/ACR-2019 and SLICC-2012 criteria have increased accuracy for SLE classification as compared to the ACR-1997 criteria (univariate DOR: 243.2 and 157.3versus78.8, respectively). In multivariable regression based on the ACR-1997 criteria, inclusion of additional features such as maculopapular rash, alopecia and hypocomplementemia significantly enhanced the model predictive capacity (area under the curve [AUC]: 0.95versus0.87 of the ACR-1997 criteria alone). Similar analysis based on the SLICC-2012 and EULAR/ACR-2019 criteria identified photosensitivity as an additional criterion significantly associated with SLE (multivariable DOR: 5.4 and 9.4, respectively). Accordingly, models including photosensitivity had superior predictive capacity over the criteria-only models (AUC: 0.94versus0.91 for SLICC-2012, 0.96versus0.91 for EULAR/ACR-2019). Furthermore, non-criteria features including Raynaud’s/livedo reticularis, anti-RNP antibodies, splenomegaly and myocarditis were independently associated with SLE thus enhancing further the predictive capacity of criteria-based models.

Conclusion:

We identified a number of criteria and non-criteria features which can be used in combination with the existing sets of criteria to increase classification of SLE patients in clinical practice. Photosensitivity could be considered as an additional feature to improve sensitivity of the recent classification criteria.

Disclosure of Interests:

Christina Adamichou: None declared, Irini Genitsaridi: None declared, Dionysis Nikolopoulos: None declared, Alessandra Bortoluzzi: None declared, Antonis Fanouriakis Paid instructor for: Paid instructor for Enorasis, Amgen, Speakers bureau: Paid speaker for Roche, Genesis Pharma, Mylan, Eleni Kalogiannaki: None declared, Emmanouil Papastefanakis: None declared, Irini Gergianaki: None declared, Prodromos Sidiropoulos: None declared, Dimitrios Boumpas: None declared, George Bertsias Grant/research support from: GSK, Consultant of: Novartis

AB0788 GENDER DIFFERENCES IN PSORIATIC ARTHRITIS DISEASE CHARACTERISTICS: EVIDENCE FOR WORSE DISEASE IN WOMEN

Background:

Psoriatic arthritis (PsA) affects both sexes equally, however there seem to be significant differences in disease expression between the genders.

Objectives:

To investigate gender differences in disease manifestations, patient-reported outcomes and comorbidities among patients with PsA.

Methods:

This cross-sectional study of patients with PsA followed at an academic rheumatology outpatient clinic between 1/6/2017 and 1/12/2019. We compared clinical characteristics, patient-reported outcomes, disease activity and comorbidities in male and female patients with PsA. All patients were over 18 years of age and fulfilled the CASPAR criteria for PsA. Differences between gender in values of continuous variables were assessed by T-tests or Mann-Whitney tests. The association between categorical variables and gender was assessed by Pearson chi-square test or Fisher’s exact test.

Results:

135 patients, 83 (62%) women and 52 (38%) men were included. Factors studied for gender differences are shown in Table 1. Women had significantly more tender (11 vs 3 p 0.001) and swollen (10 vs 3, p 0.013) joints, worse VAS (Visual Analogue Scale 0-10) pain (6 vs 5, p <0.001), higher ESR (20 vs 11, p 0.001) and worse DAPSA(Disease Activity in Psoriatic Arthritis) (33 vs 18 p 0.006) and presented with more enthesitis (32.5% vs 13.5%, p 0.013). In contrast, men achieved Minimal Disease Activity (MDA) more frequently (26.9% vs 3.6% p<0.001)and had significantly more comorbidities than women. Polyarthritic disease was more frequent in women (62% vs 31%), although at non-significant levels.

Conclusion:

Male patients with PsA have more comorbidities, while female patients have greater disease activity, worse patient reported outcomes and achieve MDA less frequently.

References:

[1]Determinants of Patient-Reported Psoriatic Arthritis Impact of Disease: An Analysis of the Association with Gender in 458 Patients from 14 Countries.

[2]Orbai AM, Perin J, et al Arthritis Care Res (Hoboken). 2019 Oct 14. doi: 10.1002/acr.24090.

FactorWomen (n=83)Men (n=52)P valueMedian (25th-75thpercentile)Age55.1 (46.8-63)56.6 (50-65.7)0.419*BMI27.9 (24.9-35)30.1 (26.8-33.3)0.181#Pso duration/ PsA duration (years)8.3 (3.9-24.5)/ 2.4 (0-5.7)14.3 (4.7-22.7)/ 2.8 (0-6.4)0.451#/0.605#Smoking (Packyears)15 (5-30)27.5 (0-46)0.002#TJC/SJC11 (4-16)/ 10 (5-17)3 (0-13)/ 3 (0-14)0.001#/0.013#VASPain/ VASGA6 (5-8)/ 5 (3-6)5 (1-6)/ 4 (2-5)<0.001*/0.121*CRP/ ESR1.4 (0.4-3.2)/20(11-33)1.1 (0.2-2.7)/ 11 (7-18)0.398#/0.001#BSA/PASI0 (0-2)/0(0-2)2 (0-6)/1(0-4.8)0.139#/0.258#DAPSA33 (24.1-45)18 (9.3-45)0.006#n (%)Enthesitis/ Dactylitis27 (32.5)/ 20 (24.1)7 (13.5)/ 10 (19.2)0.013***/ 0.508***Dyslipidemia33 (40.2)31 (59.6)0.029***Liver3 (3.6)7 (13.5)0.046**Eyes0 (0)3 (5.8)0.055**Uricemia3 (3.6)8 (15.4)0.023**Depression or anxiety16 (19.3)11 (21.1)0.817***CAD2 (2.4)12 (23.1)<0.001**DM14 (16.9)12 (23.1)0.392MDA3 (3.6)14 (26.9)<0.001

*: T-test with unequal variances;#: Mann-Whitney test; **: Fisher’s exact test; ***: Pearson chi2 test;

Pso: Psoriasis; PsA: Psoriatic arthritis; BMI: Body mass index; TJC: Tender joint count; SJC: Swollen joint count; VASPain: Visual analogue scale 0-10 for pain; VASGA: Visual analogue scale 0-10 for general assessement; CRP: C-reactive protein; ESR: Erythrocyte sedimentation rate; BSA: Body surface area; PASI: Psoriasis area severity index; DAPSA: Disease activity in psoriatic arthritis; CAD: Coronary artery disease; DM: Diabetes mellitus; MDA: Minimal disease activity;

Disclosure of Interests:

ALEXANDROS GRIVAS: None declared, IRENE KAPNIARI: None declared, KIMON TZANNIS: None declared, Dimitrios Tseronis: None declared, Michail Aggelakos: None declared, Dimitra Kassara: None declared, KATERINA HAVATZA: None declared, Sofia Flouda: None declared, Dionysis Nikolopoulos: None declared, Theofanis Karageorgas: None declared, EVAGELIA PAPADAVID: None declared, DIMITRIOS BOUMPAS Grant/research support from: Unrestricted grant support from various pharmaceutical companies, PELAGIA KATSIMPRI: None declared

FRI0155 Α MULTICENTER “AT-RISK” COHORT FOR THE DISCOVERY OF ENVIRONMENTAL, CLINICAL AND MOLECULAR PREDICTORS FOR THE TRANSITION INTO SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)

Background:

SLE onset is preceded by a preclinical phase evidenced by the presence of anti-nuclear and other autoantibodies (autoAbs), which however, have low predictive value for development of clinical SLE.

Objectives:

To define the subgroup of autoAbs-positive individuals who are at high risk for progression into SLE by integrating environmental, clinical/serological, genetic and transcriptome data.

Methods:

A multicenter, across five European countries, inception cohort of autoAbs-positive individuals or first-degree relatives (FDRs) of SLE patients who are monitored prospectively over five years for possible transition to SLE according to the classification criteria. Structured data collection on demographics, family and medical history, clinical (criteria and selected non-criteria manifestations) and serological parameters, use of medications, hydroxyvitamin D levels and lifestyle (tobacco, alcohol use, physical activity, adherence to Mediterranean diet). Blood samples are stored for RNA-sequencing and genotyping.

Results:

A total 254 at-risk individuals (93% women, 99% Caucasians, aged [mean ± standard deviation] 36 ± 12 years) have been included and enrolment/monitoring is still ongoing. Forty individuals (16%) have FDR with SLE and 88 individuals (35%) have FDR with another autoimmune disorder. The frequency of active and past use of tobacco was 28% and 20%, respectively. Sedentary lifestyle (moving only for necessary chores or outdoor activity 1-2 times/week) was reported by 54% and adherence to the Mediterranean diet was low (3.4 ± 2.3, maximum score: 9). At enrolment, individuals had 1.9 ± 1.1 ACR-1997 classification criteria, with anti-nuclear antibodies (ANA) being the most frequent (88%), followed by synovitis (39%), photosensitivity (33%) and immunologic disorder (30%) (Table 1). During follow-up of 15.2 ± 7.2 months, a total 15 individuals (5.9%) have progressed into classified SLE, including cases with severe hematological and neurological disease.

Table 1.

Baseline characteristics of the at-risk for SLE cohort

N (%) or mean ± SDACR 1997 classification criteria1.9 ± 1.1 Malar rash68 (27%) Discoid rash29 (11%) Photosensitivity83 (33%) Mucosal ulcers49 (19%) Synovitis100 (39%) Serositis30 (12%) Renal disorder28 (11%) Neurologic disorder31 (12%) Hematologic disorder58 (23%) Immunologic disorder77 (30%) ANA222 (88%)SLICC 2012 classification criteria Clinical criteria1.0 ± 0.9 Immunological criteria1.3 ± 0.9

Conclusion:

Among individuals with positive autoAbs or FDRs with SLE, the short-term risk for transition into clinical SLE is low. Following the study completion, clinical and lifestyle data will be combined with blood transcriptome to define a high-risk subgroup of individuals for progression into SLE.

Acknowledgments:

The study is supported by the Foundation for Research in Rheumatology (FOREUM; preclin016)

Disclosure of Interests:

Christina Adamichou: None declared, Dionysis Nikolopoulos: None declared, Myrto Nikoloudaki: None declared, Zahra Rahme: None declared, Micaela Fredi: None declared, Antigoni Pieta: None declared, ARGYRO REPA: None declared, Alice Parma: None declared, Eleni Kalogiannaki: None declared, Nestor Avgustidis: None declared, Nikolaos Kougkas: None declared, Aggelos Banos: None declared, Anastasios Eskitzis: None declared, Alessandra Bortoluzzi: None declared, Søren Jacobsen: None declared, Prodromos Sidiropoulos: None declared, Emmanouil Dermitzakis: None declared, Marta Mosca: None declared, Luís Inês: None declared, Laura Andreoli: None declared, Angela Tincani: None declared, Antonis Fanouriakis Paid instructor for: Paid instructor for Enorasis, Amgen, Speakers bureau: Paid speaker for Roche, Genesis Pharma, Mylan, George Bertsias Grant/research support from: GSK, Consultant of: Novartis

AB1216 INTERSTITIAL PNEUMONIA WITH AUTOIMMUNE FEATURES (IPAF): A SINGLE CENTER, PROSPECTIVE STUDY

Background:

Interstitial pneumonia with autoimmune features (IPAF)1describes a group of patients with interstitial lung disease and autoimmune features who do not meet the classification criteria for a specific connective tissue disease. Limited data regarding IPAF are available so far.

Objectives:

To identify the epidemiological and clinical characteristics of patients with IPAF and to observe disease progression, response to treatment and frequency of infections in 1-year follow-up period.

Methods:

Thirty-nine patients from ‘Attikon’ University Hospital of Athens fulfilling the IPAF criteria were enrolled. Clinical and laboratory findings, comorbidities, medications, pulmonary outcomes assessed with repeated pulmonary function tests (PFTs) and chest HRCT and complications in a 1-year follow-up period were documented for each patient. Univariate models were performed in order to identify determinants of infection and clinically significant difference in PFTs (defined as change of ≥ 10% in FVC and/or ≥ 15% in DLCO).

Results:

The mean age at the time of IPAF diagnosis was 63.2 (±11) years and 62% of the patients were female. The most common clinical features included in the IPAF criteria were arthritis (82%) and Raynaud’s phenomenon (26%). A morbilliform and/or polymorphic rash of the face, neck and extremities (not included in the IPAF criteria) was noted in 54% of patients. ANA (59%) and anti–Ro (21%) were the most common auto-antibodies. Non-specific Interstitial Pneumonia (NSIP) was the most prevalent radiological pattern (61.5%) as shown in table 1. Treatment comprised corticosteroids and immunosuppressants including hydroxychloroquine, methotrexate, azathioprine, mycophenolate and cyclophosphamide. PFTs following treatment at 6 and 12 months from baseline showed a trend of improvement (Table 2, p> 0.05). At 1 year from baseline, 20.5% of patients showed a clinically significant deterioration while 25% had a clinically significant improvement. Infections were observed in 23.1% of patients during the first semester and in 12.8% during the second semester of the follow-up period. All were respiratory tract infections and two patients (5.1%) required hospitalization. All infections occurred in patients with non-UIP pattern (p=0.02) which might be attributed to higher doses of corticosteroids used in these patients (mean initial prednisolone dose = 27 (±18) mg/d in patients with non-UIP pattern versus 17 (±16) mg/d in patients with UIP pattern, p=0.4).

Table 1.

Prevalence of HRCT patterns in 39 patients.

Radiological patternNo (%)NSIP24 (61,5%)OP2 (5,1%)NSIP with OP overlap2 (5,1%)LIP1 (2,6%)UIP7 (18%)NSIP and UIP3 (7,7%)

NSIP: Non-specific Interstitial Pneumonia, OP: Organizing Pneumonia, LIP: Lymphocytic Interstitial Pneumonia, UIP: Usual Interstitial Pneumonia.

Table 2.

PFTs at baseline, 6 and 12 months.

PFTs (% of predicted value ± SD)Baseline6 months12 monthsP valueFVC79% (±19%)82% (±18%)84% (±17%)nsDLCO49% (±16%)52% (±17%)53% (±17%)ns

Conclusion:

Rash is a common feature in IPAF and may be considered for inclusion into IPAF criteria. A trend of improvement in PFTs and a significant risk of respiratory tract infections mainly in the first semester of treatment and in patients with non-UIP radiological pattern were observed. Larger prospective studies are warranted in order to elucidate IPAF’s prognosis and to identify effective management approaches.

References:

[1]Fischer A, et al. An official European Respiratory Society/American Thoracic Society research statement: interstitial pneumonia with autoimmune features. Eur Respir J 2015; 46: 976-987.

Disclosure of Interests:

Maria Karampeli: None declared, Konstantinos Thomas: None declared, Dimitrios Tseronis: None declared, Michail Aggelakos: None declared, Dimitra Kassara: None declared, Katerina Havatza: None declared, Sofia Flouda: None declared, Dionysis Nikolopoulos: None declared, Antigoni Pieta: None declared, Vasiliki Tzavara: None declared, Pelagia Katsimbri: None declared, Dimitrios Boumpas Grant/research support from: Unrestricted grant support from various pharmaceutical companies, Theofanis Karageorgas: None declared

Evolving phenotype of systemic lupus erythematosus in Caucasians: low incidence of lupus nephritis, high burden of neuropsychiatric disease and increased rates of late-onset lupus in the 'Attikon' cohort

OBJECTIVE

This study aimed to analyse the phenotype of systemic lupus erythematosus (SLE) at first presentation and during follow-up in a newly established SLE cohort based at 'Attikon' University Hospital. The hospital combines primary, secondary and tertiary care for the region of Western Attica, Greece.

METHODS

This study comprised a mixed prevalent and incident cohort of 555 Caucasian patients diagnosed with SLE according to American College of Rheumatology 1997 criteria and/or the Systemic Lupus Erythematosus International Collaborating Clinics (SLICC) 2012 criteria. Demographic and clinical characteristics, patterns of severity, treatments and SLICC damage index were recorded for each patient at the time of diagnosis and at last evaluation.

RESULTS

The mean age at lupus diagnosis was 38.3 years (standard deviation = 15.6 years), with a median disease duration at last follow-up of two years (interquartile range 1-11). At initial presentation, the most common 'classification' manifestations were arthritis (73.3%), acute cutaneous lupus (65%) and unexplained fever (25%), while among symptoms not included in any criteria set, Raynaud's phenomenon (33%) was the most common. Kidney and neuropsychiatric involvement as presenting manifestations were present in 10.3% and 11.5% cases, respectively. Irreversible damage accrual was present in 17.8% within six months of disease diagnosis, attributed mainly to thrombotic and neuropsychiatric disease. At last evaluation, 202 (36.4%) patients had developed severe disease, of whom more than half were treated with pulse cyclophosphamide.

CONCLUSION

In this cohort of Caucasian patients, lupus nephritis is not as common as in older cohorts, while neuropsychiatric disease is emerging as a major frontier in lupus prevention and care. These data may help to document changes in the natural history and treatment of SLE over time and may have implications for its early recognition and management.

Cystoliths of Parietaria judaica can serve as an internal source of CO2 for photosynthetic assimilation when stomata are closed

The recently reported 'alarm photosynthesis' acts as a biochemical process that assimilates CO2 derived from the decomposition of calcium oxalate crystals. This study examined whether CaCO3 cystoliths could also serve as CO2 pools, fulfilling a similar role. Shoots of Parietaria judaica were subjected to carbon starvation, abscisic acid (ABA), or bicarbonate treatments, and the volume of cystoliths and the photochemical parameters of photosystem II (PSII) were determined. The size of cystoliths was reduced under carbon starvation or ABA treatments, whereas it was restored by xylem-provided bicarbonate. Under carbon starvation, ABA, or bicarbonate treatments, the photochemical efficiency of PSII was higher, while non-photochemical quenching, representing the safe dissipation of excess PSII energy due to lack of electron sinks, was lower in treated samples compared with controls. This observation suggests the involvement of ABA or other carbon starvation cues in the release of subsidiary CO2 for photosynthesis, inevitably from an internal source, which could be the cystoliths. Carbon remobilized from cystoliths can be photosynthetically assimilated, thus acting as a safety valve under stress. Together with alarm photosynthesis, these results show a tight link between leaf carbon deposits and photosynthesis.

Changes in size and composition of pigweed (Amaranthus hybridus L.) calcium oxalate crystals under CO2 starvation conditions

The functional role(s) of plant calcium oxalate (CaOx) crystals are still poorly understood. Recently, it was shown that crystals function as dynamic carbon pools whose decomposition could provide CO₂ to photosynthesis when stomata are closed (e.g. under drought conditions) and CO₂ starvation conditions may be created within the mesophyll. This biochemical process, named as 'alarm photosynthesis', can become crucial for plant survival under adverse conditions. Here, we study crystal decomposition under controlled CO₂ starvation conditions (either in the shoot or in the root) to obtain a better insight into the process of crystal formation and function. Hydroponically grown pigweed plants were kept in CO₂ -free air and/or CO₂ -free nutrient medium for 9 days. Crystal volume was monitored daily, and carbon stable isotope composition (δ¹³ C) and Fourier transformation Raman spectra were obtained at the end of the experiment. A considerable reduction in the leaf crystal volume was observed in shoot-CO₂ -starved plants at the end of the experiment. The smallest crystals were isolated from the plants in which carbon was excluded from both the shoot and the root and contained potassium nitrate. Crystal δ¹³ C of CO₂ -starved plants was altered in a predicted way. Specifically, it depended on the average calculated isotope fractionation of all carbon fixation processes considered to be contributing in each experimental treatment. The results of the present study confirmed the correlation between CO₂ starvation conditions and the CaOx crystal decomposition. Inorganic carbon fixed in the root may represent a major carbon source for CaOx formation.

Sex-specific structural and functional leaf traits and sun-shade acclimation in the dioecious tree Pistacia vera (Anacardiaceae)

In dioecious species, sex-related adaptive strategies, influenced by natural and sexual selection, allow each sex to meet the specific demands of reproduction. Differences in ecophysiological traits between males and females may rely on innate differences in secondary sex traits such as structural and functional leaf traits. We tested structural sexual leaf dimorphism in Pistacia vera L. and the intersexual differences in sun-shade acclimation processes expected from the different adaptive strategies of males and females. Fifteen structural and functional leaf traits were compared in 50-year-old trees between females with low fruit load and males under sun and shade conditions. Despite the low additional energy investment in reproduction in females, remarkable sex effects in leaf structure and function were observed. Male trees had smaller leaves with significantly lower total conducting petiole area (TCA) and higher stomatal density, water use efficiency and concentration of phenolic compounds; females had larger leaves with greater thickness, leaf mass per area, TCA and maximum photosynthetic capacity per area (Amax,a). The higher Amax,a and stomatal conductance of female leaves were associated with their ~20-fold higher TCA compared with male trees. Females seem to invest more in high xylem efficiency and rates of C gain; males invest more in defence-protection. Sun-shade plastic responses were sex- and trait-specific, but the plasticity assessment indicated that both sexes have evolved an almost equal degree of phenotypic plasticity that allows them to perform optimally under varying environmental conditions. However, the trait-specific differences indicate that each sex displays a different strategy of optimisation.

Changes in the properties of calcium-carbon inclusions during leaf development and their possible relationship with leaf functional maturation in three inclusion-bearing species

In many plant species, carbon-calcium inclusion (calcium oxalate crystals or cystoliths containing calcium carbonate) formation is a fundamental part of their physiology even necessary for normal growth and development. Despite the long-standing studies on carbon-calcium inclusions, the alterations in their properties during leaf development and their possible association with the maturation of the photosynthetic machinery have not been previously examined. In order to acquire more insights into this subject, we examined three of the most common species bearing abundant inclusions of different types, i.e., Amaranthus hybridus, Vitis vinifera, and Parietaria judaica. Results of our study showed that, irrespective of species and type of inclusion, similar patterns in the alterations of their properties are observed during leaf maturation, except for some differences in cell differentiation and distribution between raphides and druses in Vitis vinifera. As expected, inclusion formation has taken place at very early developmental stages and maximum density was observed in very young leaves. Inclusion properties are changing in a coordinated way with leaf area and these modifications are compatible with the concept that each idioblast or lithocyst "services" a finite number/area of adjacent cells. This tight coordination is also evident at the whole leaf level. Moreover, we observed an association of the properties of carbon-calcium inclusions and gas exchange, suggesting a possible implication of these structures in photosynthesis.

How does long-term drought acclimation modify structure-function relationships? A quantitative approach to leaf phenotypic plasticity of barley

Under drought conditions the growth and survival of a plant depend on its adaptive characteristics and acclimation ability. Adaptation refers to inherent morpho-physiological characters providing protection against water losses. Acclimation, however, is a special case of phenotypic plasticity: environment-dependent phenotypic expression resulting to a 'new' phenotype through drought-induced modulations in leaf morphology, anatomy and physiology. Given that phenotypic plasticity influences environmental tolerance, a multi-trait plasticity index could be of great importance. Therefore, we examined the acclimation processes of three different barley genotypes using a multi-trait plasticity assessment with emphasis on the leaf water economy-related traits. Our results showed that (i) the structure-function co-ordination during long-term drought acclimation follows the trade-off between carbon gain and water saving as well as the competition between investments in photosynthesis vs synthesis of protective compounds; (ii) the genotypes with smaller leaf area, narrower and denser veins, as well as smaller and denser stomata i.e. traits providing tolerance, exhibited less drastic adjustments under stress conditions, suggesting a trade-off between acclimation and tolerance-adaptation; and (iii) the slope values of a multi-trait 'reaction norm' based on regression analysis of PCA scores were indicative of the degree of plasticity for each genotype, providing an accurate representation of a complex set of data with single numeric results easily comparable.

Reevaluation of the plant "gemstones": Calcium oxalate crystals sustain photosynthesis under drought conditions

Land plants face the perpetual dilemma of using atmospheric carbon dioxide for photosynthesis and losing water vapors, or saving water and reducing photosynthesis and thus growth. The reason behind this dilemma is that this simultaneous exchange of gases is accomplished through the same minute pores on leaf surfaces, called stomata. In a recent study we provided evidence that pigweed, an aggressive weed, attenuates this problem exploiting large crystals of calcium oxalate as dynamic carbon pools. This plant is able to photosynthesize even under drought conditions, when stomata are closed and water losses are limited, using carbon dioxide from crystal decomposition instead from the atmosphere. Abscisic acid, an alarm signal that causes stomatal closure seems to be implicated in this function and for this reason we named this path "alarm photosynthesis." The so-far "enigmatic," but highly conserved and widespread among plant species calcium oxalate crystals seem to play a crucial role in the survival of plants.

Alarm Photosynthesis: Calcium Oxalate Crystals as an Internal CO2 Source in Plants

Calcium oxalate crystals are widespread among animals and plants. In land plants, crystals often reach high amounts, up to 80% of dry biomass. They are formed within specific cells, and their accumulation constitutes a normal activity rather than a pathological symptom, as occurs in animals. Despite their ubiquity, our knowledge on the formation and the possible role(s) of these crystals remains limited. We show that the mesophyll crystals of pigweed (Amaranthus hybridus) exhibit diurnal volume changes with a gradual decrease during daytime and a total recovery during the night. Moreover, stable carbon isotope composition indicated that crystals are of nonatmospheric origin. Stomatal closure (under drought conditions or exogenous application of abscisic acid) was accompanied by crystal decomposition and by increased activity of oxalate oxidase that converts oxalate into CO2 Similar results were also observed under drought stress in Dianthus chinensis, Pelargonium peltatum, and Portulacaria afra Moreover, in A. hybridus, despite closed stomata, the leaf metabolic profiles combined with chlorophyll fluorescence measurements indicated active photosynthetic metabolism. In combination, calcium oxalate crystals in leaves can act as a biochemical reservoir that collects nonatmospheric carbon, mainly during the night. During the day, crystal degradation provides subsidiary carbon for photosynthetic assimilation, especially under drought conditions. This new photosynthetic path, with the suggested name "alarm photosynthesis," seems to provide a number of adaptive advantages, such as water economy, limitation of carbon losses to the atmosphere, and a lower risk of photoinhibition, roles that justify its vast presence in plants.

"Carbon gain vs. water saving, growth vs. defence": two dilemmas with soluble phenolics as a joker

Despite that phenolics are considered as a major weapon against herbivores and pathogens, the primal reason for their evolution may have been the imperative necessity for their UV-absorbing and antioxidant properties in order for plants to compensate for the adverse terrestrial conditions. In dry climates the choice concerning the first dilemma (carbon gain vs. water saving) needs the appropriate structural and metabolic modulations, which protect against stresses such as high UV and visible radiation or drought, but reduce photosynthesis and increase oxidative pressure. Thus, when water saving is chosen, priority is given to protection (including phenolic synthesis), instead of carbon gain and hence growth. At the global level, the different choices by the individual species are expressed by an interspecific negative relationship between total phenolics and photosynthesis. On the other hand, the accumulation of phenolics in water saving plants offers additional defensive functions because these multifunctional compounds can also act as pro-oxidant, antifeeding or toxic factors. Therefore phenolics, as biochemical jokers, can give the answer to both dilemmas: water saving involves high concentrations of phenolics which also offer high level of defence.

Cessation of photosynthesis in Lotus japonicus leaves leads to reprogramming of nodule metabolism

Symbiotic nitrogen fixation (SNF) involves global changes in gene expression and metabolite accumulation in both rhizobia and the host plant. In order to study the metabolic changes mediated by leaf-root interaction, photosynthesis was limited in leaves by exposure of plants to darkness, and subsequently gene expression was profiled by real-time reverse transcription-PCR (RT-PCR) and metabolite levels by gas chromatography-mass spectrometry in the nodules of the model legume Lotus japonicus. Photosynthetic carbon deficiency caused by prolonged darkness affected many metabolic processes in L. japonicus nodules. Most of the metabolic genes analysed were down-regulated during the extended dark period. In addition to that, the levels of most metabolites decreased or remained unaltered, although accumulation of amino acids was observed. Reduced glycolysis and carbon fixation resulted in lower organic acid levels, especially of malate, the primary source of carbon for bacteroid metabolism and SNF. The high amino acid concentrations together with a reduction in total protein concentration indicate possible protein degradation in nodules under these conditions. Interestingly, comparisons between amino acid and protein content in various organs indicated systemic changes in response to prolonged darkness between nodulated and non-nodulated plants, rendering the nodule a source organ for both C and N under these conditions.

Photosynthetic capacity is negatively correlated with the concentration of leaf phenolic compounds across a range of different species

BACKGROUND AND AIMS

Phenolic compounds are the most commonly studied of all secondary metabolites because of their significant protective-defensive roles and their significant concentration in plant tissues. However, there has been little study on relationships between gas exchange parameters and the concentration of leaf phenolic compounds (total phenolics (TP) and condensed tannins (CT)) across a range of species. Therefore, we addressed the question: is there any correlation between photosynthetic capacity (A(max)) and TP and CT across species from different ecosystems in different continents?

METHODOLOGY

A plethora of functional and structural parameters were measured in 49 plant species following different growth strategies from five sampling sites located in Greece and Australia. The relationships between several leaf traits were analysed by means of regression and principal component analysis.

PRINCIPAL RESULTS

The results revealed a negative relationship between TP and CT and A(max) among the different plant species, growth strategies and sampling sites, irrespective of expression (with respect to mass, area or nitrogen content). Principal component analysis showed that high concentrations of TP and CT are associated with thick, dense leaves with low nitrogen. This leaf type is characterized by low growth, A(max) and transpiration rates, and is common in environments with low water and nutrient availability, high temperatures and high light intensities. Therefore, the high TP and CT in such leaves are compatible with the protective and defensive functions ascribed to them.

CONCLUSIONS

Our results indicate a functional integration between carbon gain and the concentration of leaf phenolic compounds that reflects the trade-off between growth and defence/protection demands, depending on the growth strategy adopted by each species.

The winter-red-leaf syndrome in Pistacia lentiscus: evidence that the anthocyanic phenotype suffers from nitrogen deficiency, low carboxylation efficiency and high risk of photoinhibition

Recent evidence indicates that winter-red leaf phenotypes in the mastic tree (Pistacia lentiscus) are more vulnerable to chronic photoinhibition during the cold season relative to winter-green phenotypes occurring in the same high light environment. This was judged by limitations in the maximum quantum yield of photosystem II (PSII), found in previous studies. In this investigation, we asked whether corresponding limitations in leaf gas exchange and carboxylation reactions could also be manifested. During the cold ("red") season, net CO₂ assimilation rates (A) and stomatal conductances (g(s)) in the red phenotype were considerably lower than in the green phenotype, while leaf internal CO₂ concentration (Ci) was higher. The differences were abolished in the "green" period of the year, the dry summer included. Analysis of A versus Ci curves indicated that CO₂ assimilation during winter in the red phenotype was limited by Rubisco content and/or activity rather than stomatal conductance. Leaf nitrogen levels in the red phenotype were considerably lower during the red-leaf period. Consequently, we suggest that the inherently low leaf nitrogen levels are linked to the low net photosynthetic rates of the red plants through a decrease in Rubisco content. Accordingly, the reduced capacity of the carboxylation reactions to act as photosynthetic electron sinks may explain the corresponding loss of PSII photon trapping efficiency, which cannot be fully alleviated by the screening effect of the accumulated anthocyanins.

Early postexercise thallium-201 reinjection after sublingual nitroglycerin augmentation: effects on detection of myocardial ischemia and/or viability

BACKGROUND

Thallium-201 (201Tl) reinjection after conventional redistribution imaging is a standard procedure, resulting in enhanced 201Tl redistribution which is compatible with viable myocardium. Although this method significantly improves identification of viable myocardium, it increases the investigation time by approximately 1 h. Thus, this technique is suboptimal from the standpoint of patient convenience, since its routine performance may be impractical in a high-volume nuclear medicine laboratory.

HYPOTHESIS

This study was undertaken to evaluate the efficacy of an early 201Tl reinjection and imaging protocol in combination with sublingual nitroglycerin, to detect myocardial ischemia and/or viability, and to reduce the need for conventional (4 h) redistribution imaging.

MATERIALS AND METHODS

In this study, 62 consecutive coronary patients, referred for the detection of possible myocardial ischemia and/or viability, were involved (mean age 55 years, range 41-70). Of those, 50 had previous angina attacks, with 42 having a history of previous myocardial infarction; 10 patients had coronary artery bypass grafting; and the remaining 2 had atypical chest pain. Immediately after the completion of the initial postexer-cise imaging, 0.3 mg sublingual nitroglycerin followed by the reinjection of 1 m Ci of 201Tl were administered, and two further sets of images were acquired 1 h and 4 h later.

RESULTS

In each set of images, a total of 496 segments were analyzed. On postexercise imaging, 305 (61%) segments demonstrated defects of which 198 (65%) showed enhanced thallium uptake, 97 (32%) did not change, and 10 (3%) showed reverse redistribution on 1 h reinjection imaging (IRI). Of the 97 persistent defects, only 17 (6%) showed fill-in of 201Tl on 4 h redistribution imaging (CRI), while 12 (4%) segments showed reverse redistribution. On the other hand, after analyzing the 62 patients of the 1 h IRI, 17 (27%) remained unchanged while in only 1 patient (6%) of 17 the diagnosis changed from myocardial necrosis to ischemia after analysis of the 4 h CRI.

CONCLUSION

These results indicate that early postexercise reinjection of 201Tl in combination with sublingual nitroglycerin followed by 1 h image acquisition may prove useful for a comprehensive and convenient assessment of myocardial ischemia and/or viability.

The photoprotective role of epidermal anthocyanins and surface pubescence in young leaves of grapevine (Vitis vinifera)

BACKGROUND AND AIMS

Depending on cultivar, surfaces of young leaves of Vitis vinifera may be glabrous-green ('Soultanina') or transiently have anthocyanins ('Siriki') or pubescence ('Athiri'). A test is made of the hypothesis that anthocyanins and pubescence act as light screens affording a photoprotective advantage to the corresponding leaves, and an assessment is made of the magnitude of their effect.

METHODS

Measurements were made on young leaves of the three cultivars in spring under field conditions. Photosynthetic gas-exchange and in vivo chlorophyll fluorescence were measured. Photosynthetic and photoprotective pigments were analysed by HPLC.

KEY RESULTS

Compared with glabrous-green leaves, both anthocyanic and pubescent leaves had greater dark-adapted PSII photochemical efficiency and net photosynthesis. In leaves possessing either anthocyanins or pubescence, the ratio of xanthophyll cycle components to total chlorophyll, and mid-day de-epoxidation state of the xanthophyll cycle were considerably smaller, than in glabrous-green leaves. These differences were more evident in pubescent leaves, probably indicating that trichomes were more effective in decreasing light stress than anthocyanins in the epidermis.

CONCLUSIONS

Light screens, especially in the form of pubescence, decrease the risk of photoinhibition whilst allowing leaves to maintain a smaller content of xanthophyll cycle components and depend less on xanthophyll cycle energy dissipation. This combination of photoprotective features, i.e. decreased photon flux to the photosynthetic apparatus and lower xanthophyll cycle utilization rates may be particularly advantageous under stressful conditions.

A theoretical model evaluating the angular distribution of luminescence emission in X-ray scintillating screens

The aim of this study was to examine the angular distribution of the light emitted from radiation-excited scintillators in medical imaging detectors. This distribution diverges from Lambert's cosine law and affects the light emission efficiency of scintillators, hence it also affects the dose burden to the patient. In the present study, the angular distribution was theoretically modeled and was used to fit experimental data on various scintillator materials. Results of calculations revealed that the angular distribution is more directional than that predicted by Lambert's law. Divergence from this law is more pronounced for high values of light attenuation coefficient and thick scintillator layers (screens). This type of divergence reduces light emission efficiency and hence it increases the incident X-ray flux required for a given level of image brightness.

Radon exposure in the thermal spas of Lesvos Island--Greece

The aim of this work is to study the exposure due to radon to bathers and personnel in the spas of Lesvos Island under a specific use pattern. 222Rn concentrations in the supplying water were measured during a long time period. Variations in indoor 222Rn, attached and unattached progenies, and influence of the ambient atmosphere were thoroughly analysed during bath treatment for the purpose of investigating a consequent probable short-term health impact. Concentration peaks both for 222Rn and PAEC were found to appear during bathtubs filling. These peaks considered imposing an additional short-term radiation burden for spa users. The additional doses delivered to bathers during bath treatment were found to be very low and for personnel did not exceed the value of 5 mSv per year.

Study of a Greek area with enhanced indoor radon concentrations

In this paper the focus is on Arnea Chalkidikis, an area in Greece with granitic geological background and indications of possible elevated radon concentration indoors. Data are reported of indoor radon measurements with etched track detectors and those are used for dosimetric estimations. Moreover, data are reported on soil gas and soil radon concentrations in Arnea, as well as radon and uranium concentrations in water samples. From the measured radon concentrations in water samples the contribution to the overall dose has been calculated. For a period of 1 month, indoor radon and progeny activity has also been monitored in the dwelling that has the maximum indoor radon concentration in Greece. This dwelling is in Arnea and the dose delivered to the inhabitants has been calculated. The mean annual effective dose due to indoor radon was 4.5 mSv and about 11% of this was due to the use of water. Mean soil gas concentration and soil radon concentration were (90 +/- 30) kBq m(-3) (p<0.05) and (30 +/- 5) kBq m(-3) (p<0.05) respectively. Mean uranium concentration of the water samples was (98 +/- 13) mBq l(-1) (p<0.05).

The relationship between anatomy and photosynthetic performance of heterobaric leaves

Heterobaric leaves show heterogeneous pigmentation due to the occurrence of a network of transparent areas that are created from the bundle sheaths extensions (BSEs). Image analysis showed that the percentage of photosynthetically active leaf area (Ap) of the heterobaric leaves of 31 plant species was species dependent, ranging from 91% in Malva sylvestris to only 48% in Gynerium sp. Although a significant portion of the leaf surface does not correspond to photosynthetic tissue, the photosynthetic capacity of these leaves, expressed per unit of projected area (Pmax), was not considerably affected by the size of their transparent leaf area (At). This means that the photosynthetic capacity expressed per Ap (P*max) should increase with At. Moreover, the expression of P*max could be allowing the interpretation of the photosynthetic performance in relation to some critical anatomical traits. The P*max, irrespective of plant species, correlated with the specific leaf transparent volume (lambda(t)), as well as with the transparent leaf area complexity factor ((CF)A(t)), parameters indicating the volume per unit leaf area and length/density of the transparent tissues, respectively. Moreover, both parameters increased exponentially with leaf thickness, suggesting an essential functional role of BSEs mainly in thick leaves. The results of the present study suggest that although the Ap of an heterobaric leaf is reduced, the photosynthetic performance of each areole is increased, possibly due to the light transferring capacity of BSEs. This mechanism may allow a significant increase in leaf thickness and a consequent increase of the photosynthetic capacity per unit (projected) area, offering adaptive advantages in xerothermic environments.

Thallium-201 for detection of myocardial viability: comparison of early postexercise reinjection and imaging with 4 and 18-24 hours redistribution imaging

To evaluate the efficacy of an early 201Tl reinjection and imaging protocol for reducing the need for conventional 4-hour or optimal 24-hour redistribution imaging (RI) and detecting of myocardial viability, we compared the results of early postexercise Tl reinjection and imaging with those of 4- and 24-hour RI in 74 consecutive patients aged 55 +/- 9 years (mean +/- SD) who were assessed for myocardial ischemia. One millicurie of Tl was injected promptly after completion of the initial postexercise imaging (PEX) and three additional sets of images were acquired 1, 4 and 18-24 h later. A total of 2,368 segments were evaluated. On PEX, 390 (17%) segments showed defects, of which 287 (74%) showed enhanced Tl uptake at 1-hour RI; 89 (23%) did not change and 14 (4%) showed reverse redistribution. Of the 103 persistent defects, only 27 (7%) showed further fill-in of Tl; 62 (16%) segments showed reverse redistribution at 4-hour RI while at 18- to 24-hour RI 17 (4%) and 47 (12%) segments showed further fill-in of Tl and reverse redistribution, respectively. Finally, after analysis of 4- and 18- to 24-hour RI, the diagnosis changed from myocardial necrosis to ischemia in only 2 (3%) patients. In conclusion, these results suggest that by eliminating the need for an additional delayed set of images for detection of myocardial viability, this protocol reduces the total investigation procedure, is more convenient for the patient, increases patient turnover and expedites the decision-making process.