AB0075 IDENTIFICATION OF NOVEL ACETYLATED ANTIGENS IN IMMUNE COMPLEXES OF SYNOVIAL FLUID FROM RA PATIENTS

Background

Rheumatoid arthritis (RA) is an autoimmune disease characterized by genetic predisposition and associated immunological features including the production of autoantibodies against various epitopes. Several pathways have been implicated in the induction of autoantibodies against novel epitopes through post-translational modifications such as citrullination, carbamylation and acetylation (1). However, the contributions of these anti-modified protein antibodies (AMPAs) in the pathogenesis and formation of immune complexes (IC) in the synovial fluid has not been fully uncovered.

Objectives

To analyze reactivity of monomeric and IC antibodies of RA patients to citrullinated, carbamylated and acetylated modified antigens in comparison to disease control group and healthy donors.

Methods

Synovial fluid (SF) was collected from 17 RA patients and 40 individuals from a disease control group (CG) including reactive arthritis and psoriasis arthritis. Paired serum and SF samples were used from 16 RA and 19 CG compared to serum from 70 healthy donors (HD). Immune complexes (IC) were purified from sera and SF by applying a technique using purified human C1q, which was immobilised on magnetic tosylactivated microparticles (Dynabeads M-280) according to the manufacturer’s recommendations for activation of amine groups. Additionally, sucrose gradient centrifugation was used to fractionate SF and sera into 21 fractions and according to protein markers, protein G was used to isolate monomeric IgG from fractions 3-9 and IC IgG from fractions 11-22. ELISA kits for anti CCP-IgG, anti-mutated citrullinated vimentin (MCV)-IgG, anti-acetylated Lysine Antibody (anti-HC55)-IgG and anti-carbamylated vimentin (carbVim)-IgG were used to test reactivity against modified proteins. Extracted antigens from the IC were investigated with Western blot for specific modifications or individual antigens with the corresponding antibodies. Citrullinated and acetylated vimentin was identified as part of IC via mass spectroscopy. Purified AMPAs from serum or SF (isolated from IC or as soluble antibodies) were investigated on a custom-made LineBlot array containing 24 different antigens either citrullinated, carbamylated, acetylated or unmodified/native counterparts.

Results

Titers of anti-CCP, anti-MCV and anti-acetylated (anti-HC55) reactivity were higher in SF of RA patients compared to CG. AMPAs were detected in SF in IC as well as free antibodies. Some isolated IgG (monomeric and IC) showed reactivities against citrullinated and acetylated peptides that could not be detected in native samples. Surprisingly, in addition to citrullinated vimentin, the acetelylated form was also detected in the IC eluted fractions. Haptoglobin and fibrinogen fragments were identified as carbamylated modified proteins in small concentrations. The spectrum of identified acetylated proteins included human proteins such as histones as well as fragments of bacterial filament proteins. SF of RA patients showed reactivity against MCV and citrullinated desmin in LineBlot array.

Conclusion

AMPAs recognize different modified antigens and form immune complexes in the SF of RA patients. The elevated titer of anti-acetylated protein antibodies and the inclusion of its epitope in immune complexes in the synovium points to its contribution in the pathogenesis of RA.

Figure 1.

The identification of acetylated antigens in the synovium of RA patients is especially intriguing, as infections (bacteria) are known to not only acetylate their own proteins, but also modify host proteins.

References

[1]Grönwall C, Liljefors L, Bang H, et al. A Comprehensive Evaluation of the Relationship Between Different IgG and IgA Anti-Modified Protein Autoantibodies in Rheumatoid Arthritis. Front Immunol. 2021;12:627986-.

Acknowledgements

This work was supported by a grant from DFG.

Disclosure of Interests

Khetam Ghannam: None declared, Holger Bang Employee of: Employee of ORGENTEC Diagnostika GmbH, Thomas Häupl: None declared, Sarah Ohrndorf: None declared, Jan Zernicke: None declared, Ulrike Kuckelkorn: None declared, Eugen Feist: None declared, Gerd Rüdiger Burmester: None declared

POS0583 RHEUMATOID ARTHRITIS BENEFITS FROM FASTING AND PLANT-BASED DIET: AN EXPLORATORY RANDOMIZED CONTROLLED TRIAL (NUTRIFAST)

Background

Fasting has been shown to be beneficial in many diseases, including rheumatoid arthritis (RA). Among other effects, fasting stimulates ketogenic metabolism, induces autophagy, and harbors immunomodulatory functions. Recent studies have highlighted the role of the intestinal microbiota in the still unclear etiology of RA1. This could be a potential target for additional dietary therapy in RA.

Objectives

To investigate the effect of therapeutic fasting followed by a plant-based diet compared to standard dietary recommendations in patients with RA.

Methods

In this pilot study2 patients with RA were randomized to either a 7-day fast (≤250kcal/d) followed by 11 weeks of plant-based diet or to conventional nutritional counselling according to the recommendations of the German Society for Nutrition (Deutsche Gesellschaft für Ernährung, DGE) for 12 weeks. Disease activity and treatment response in RA (including Health Assessment Questionnaire, HAQ; EULAR Response Criteria, ACR Response Criteria) were measured at baseline (T0), day 7 (T1), 6 weeks (T2) and 12 weeks (T3).

Results

A total of 50 from 53 enrolled participants were included into the per-protocol analysis. The mean age was 51.98 ± 9.4 years with symptoms duration of 6.8 ± 8.1 years; 92% were females and 78% were ACPA and/or RF IgM positive. At baseline, participants presented HAQ 0.8 ± 0.5, DAS28CRP 4.0 ± 1.3, CRP 3.1 ± 3.8 mg/L, and a BMI of 25.0 ± 3.7 kg/m2.

The primary endpoint did not become significant. However, post-hoc analyses revealed clinically relevant improvements in the HAQ after 12 weeks in both the fasting and the DGE group (Δ-0.29; 95% CI, -0.45 to -0.13; p = 0.001; and Δ-0.23; 95% CI, -0.45 to -0.22; p = 0.032; respectively). Furthermore, the effect already set on by day 7 in the fasting group compared to week 6 in the DGE group (Figure 1). This effect was independent of antibody status, delivery mode of the intervention or previous dietary forms. CV risk factors including weight and total cholesterol levels improved stronger in the fasting group compared to the DGE group (Δ-3.9 kg vs. -0.7kg; 95% CI, 1.4 to 5.0; p = 0.001 and Δ-18.60 mg/dl vs Δ6.44 mg/dl; 95% CI, 7.3 to 42.8, p=0.007).

Figure 1.

EULAR and ACR Response until week 12 and HAQ up to 6 months. ACR, American College of Rheumatology; CI, confidence interval; HAQ, health assessment questionnaire.

Conclusion

Fasting followed by a plant-based diet positively impacts disease activity and CV risk factors in RA, comparable to and no lesser than those of an anti-inflammatory diet according to the DGE. These results may open new perspectives by dietary interventions in an integrative therapeutic approach. Further confirmatory clinical studies with larger patient numbers are needed to confirm these exploratory findings.

References

[1]Ruff WE, Greiling TM, Kriegel MA. Host–microbiota interactions in immune-mediated diseases. Nature Reviews Microbiology 2020;18(9):521-38. doi: 10.1038/s41579-020-0367-2

[2]Hartmann AM, Dell’Oro M, Kessler CS, et al. Efficacy of therapeutic fasting and plant-based diet in patients with rheumatoid arthritis (NutriFast): study protocol for a randomised controlled clinical trial. BMJ Open 2021;11(8):e047758. doi: 10.1136/bmjopen-2020-047758 [published Online First: 2021/08/13]

Disclosure of Interests

Anika M. Hartmann: None declared, Farid I. Kandil: None declared, Nico Steckhan: None declared, Thomas Häupl: None declared, Christan S. Kessler: None declared, Andreas Michalsen Paid instructor for: co-founder and instructor in the Academy of Integrative Fasting, Daniela A. Koppold-Liebscher Paid instructor for: co-founder and instructor in the Academy of Integrative Fasting.

Monitoring of patients with rheumatoid arthritis by indocyanine green (ICG)-enhanced fluorescence optical imaging treated with anti-TNFα therapy

BACKGROUND

Fluorescence optical imaging (FOI) enables visualisation of inflammation in both hands in rheumatoid arthritis (RA).

OBJECTIVE

To investigate the usefulness of FOI in treatment monitoring under anti-TNFα therapy with certolizumab pegol (CZP) in patients with RA in comparison to clinical and laboratory outcome parameters.

METHODS

CZP-naïve patients with RA were eligible for this open-label study with an observational period of 52 weeks. Disease activity was monitored by the clinical score DAS28, tender/swollen joint count (TJC-28/SJC-28) and laboratory outcomes for systemic inflammation (CRP and ESR). FOI results were analysed in three different phases (P1-3) and PrimaVistaMode (PVM) by the FOI activity score (FOIAS).

RESULTS

Twenty-eight RA patients (median age 52.5 years, 26 females, thirteen with a history of other biologic therapy) were included. DAS28 (CRP) decreased from moderate disease activity at baseline (median 4.6, IQR 1.8) to low disease activity at week (w)52 (median 2.7, IQR 2.1; p < 0.001). Statistically significant decreases could also be demonstrated for SJC-28 and TJC-28. CRP/ESR were reduced numerically from baseline to w52. FOIAS in P1 (early phase) showed a continuous decrease of enhancement during the course of treatment period: from baseline (median 1.5, IQR 9.3) over w6 (median 1.0, IQR 3.0; p = 0.069), w12 (median 0.5, IQR 3.0; p = 0.171), w24 (n = 27, median 0.0, IQR 3.0; p = 0.004), until w52 (n = 18, median 0.0, IQR 2.8; p = 0.091), which could not be presented for FOIAS in P2, P3 and PVM.

CONCLUSION

FOI in P1 appears to be a valuable tool for fast and easy monitoring of treatment response to certolizumab in a clinical setting.

[Biomarkers and imaging for diagnosis and stratification of rheumatoid arthritis and spondylarthritis in the BMBF consortium ArthroMark]

Rheumatic diseases are among the most common chronic inflammatory disorders. Besides severe pain and progressive destruction of the joints, rheumatoid arthritis (RA), spondyloarthritides (SpA) and psoriatic arthritis (PsA) impair working ability, reduce quality of life and if treated insufficiently may enhance mortality. With the introduction of biologics to treat these diseases, the demand for biomarkers of early diagnosis and therapeutic stratification has been growing continuously. The main goal of the consortium ArthroMark is to identify new biomarkers and to apply modern imaging technologies for diagnosis, follow-up assessment and stratification of patients with RA, SpA and PsA. With the development of new biomarkers for these diseases, the ArthroMark project contributes to research in chronic diseases of the musculoskeletal system. The cooperation between different national centers will utilize site-specific resources, such as biobanks and clinical studies for sharing and gainful networking of individual core areas in biomarker analysis. Joint data management and harmonization of data assessment as well as best practice characterization of patients with new imaging technologies will optimize quality of marker validation.

[Relevance of big data for molecular diagnostics]

Big data analysis raises the expectation that computerized algorithms may extract new knowledge from otherwise unmanageable vast data sets. What are the algorithms behind the big data discussion? In principle, high throughput technologies in molecular research already introduced big data and the development and application of analysis tools into the field of rheumatology some 15 years ago. This includes especially omics technologies, such as genomics, transcriptomics and cytomics. Some basic methods of data analysis are provided along with the technology, however, functional analysis and interpretation requires adaptation of existing or development of new software tools. For these steps, structuring and evaluating according to the biological context is extremely important and not only a mathematical problem. This aspect has to be considered much more for molecular big data than for those analyzed in health economy or epidemiology. Molecular data are structured in a first order determined by the applied technology and present quantitative characteristics that follow the principles of their biological nature. These biological dependencies have to be integrated into software solutions, which may require networks of molecular big data of the same or even different technologies in order to achieve cross-technology confirmation. More and more extensive recording of molecular processes also in individual patients are generating personal big data and require new strategies for management in order to develop data-driven individualized interpretation concepts. With this perspective in mind, translation of information derived from molecular big data will also require new specifications for education and professional competence.

A Detailed Analysis of the Morphology of Fibrils of Selectively Mutated Amyloid β (1-40)

A small library of rationally designed amyloid β [Aβ(1-40)] peptide variants is generated, and the morphology of their fibrils is studied. In these molecules, the structurally important hydrophobic contact between phenylalanine 19 (F19) and leucine 34 (L34) is systematically mutated to introduce defined physical forces to act as specific internal constraints on amyloid formation. This Aβ(1-40) peptide library is used to study the fibril morphology of these variants by employing a comprehensive set of biophysical techniques including solution and solid-state NMR spectroscopy, AFM, fluorescence correlation spectroscopy, and XRD. Overall, the findings demonstrate that the introduction of significant local physical perturbations of a crucial early folding contact of Aβ(1-40) only results in minor alterations of the fibrillar morphology. The thermodynamically stable structure of mature Aβ fibrils proves to be relatively robust against the introduction of significantly altered molecular interaction patterns due to point mutations. This underlines that amyloid fibril formation is a highly generic process in protein misfolding that results in the formation of the thermodynamically most stable cross-β structure.

High quality reduced graphene oxide flakes by fast kinetically controlled and clean indirect UV-induced radical reduction

This work highlights a surprisingly simple and kinetically controlled highly efficient indirect method for the production of high quality reduced graphene oxide (rGO) flakes via UV irradiation of aqueous dispersions of graphene oxide (GO), in which the GO is not excited directly. While the direct photoexcitation of aqueous GO (when GO is the only light-absorbing component) takes several hours of reaction time at ambient temperature (4 h) leading only to a partial GO reduction, the addition of small amounts of isopropanol and acetone (2% and 1%) leads to a dramatically shortened reaction time by more than two orders of magnitude (2 min) and a very efficient and soft reduction of graphene oxide. This method avoids the formation of non-volatile species and in turn contamination of the produced rGO and it is based on the highly efficient generation of reducing carbon centered isopropanol radicals via the reaction of triplet acetone with isopropanol. While the direct photolysis of GO dispersions easily leads to degradation of the carbon lattice of GO and thus to a relatively low electric conductivity of the films of flakes, our indirect photoreduction of GO instead largely avoids the formation of defects, keeping the carbon lattice intact. Mechanisms of the direct and indirect photoreduction of GO have been elucidated and compared. Raman spectroscopy, XPS and conductivity measurements prove the efficiency of the indirect photoreduction in comparison with the state-of-the-art reduction method for GO (hydriodic acid/trifluoroacetic acid). The rapid reduction times and water solvent containing only small amounts of isopropanol and acetone may allow easy process up-scaling for technical applications and low-energy consumption.

Intermediates caught in the act: tracing insulin amyloid fibril formation in time by combined optical spectroscopy, light scattering, mass spectrometry and microscopy

Insulin under acidic conditions. PDB-Databank structure visualized with VMD.

Biocompatible silicon surfaces through orthogonal click chemistries and a high affinity silicon oxide binding peptide

Multifunctionality is gaining more and more importance in the field of improved biomaterials. Especially peptides feature a broad chemical variability and are versatile mediators between inorganic surfaces and living cells. Here, we synthesized a unique peptide that binds to SiO(2) with nM affinity. We equipped the peptide with the bioactive integrin binding c[RGDfK]-ligand and a fluorescent probe by stepwise Diels-Alder reaction with inverse electron demand and copper(I) catalyzed azide-alkyne cycloaddition. For the first time, we report the generation of a multifunctional peptide by combining these innovative coupling reactions. The resulting peptide displayed an outstanding binding to silicon oxide and induced a significant increase in cell spreading and cell viability of osteoblasts on the oxidized silicon surface.

[DNA microarrays]

Since their development in the 1990s DNA microarrays have advanced to one of the most important technologies for biomedical research. Miniaturization enables up to 1 million different sequence-specific DNA hybridization tests to be performed on an area of less than 2 cm². Depending on the selection of oligonucleotide sequences, which are assembled on a microarray and on the treatment of samples prior to hybridization, up to genome-wide analyses for genotypes, gene expression, epigenetic changes or promoter activation can be performed. Increasing knowledge about the human genome advances commercial pre-assembly of DNA microarrays with selected oligonucleotide sequences for specialized applications. In clinical rheumatology gene expression analyses in treatment studies are of increasing importance. Similarly, this technique also identified new biomarkers that allow even better assessment of the current disease activity. The varieties of application enable the possibility of systematic research on the immunological response to specific patterns after stimulation. This opens up opportunities to detect and differentiate immunological reaction patterns better.

Does gene expression analysis inform us in rheumatoid arthritis?

Transcription profiling has become a standard technology in research. It is mainly applied in the search for biomarkers to improve diagnostic and prognostic classification, to quantify disease activity and to predict or indicate response to therapy. This review will focus on rheumatoid arthritis and discuss considerations for sample selection, prerequisites for functional interpretation of data and the current status of information deduced in the field of biomarkers for the various clinical questions. In the next few years, prediction of response to treatment is the most important aim of biomarker research. With the growing number of new biological agents, there is increasing pressure to identify molecular parameters that will not only guide the therapeutic decision but also help to define the most important targets for which new biological agents should be tested in clinical studies.

Interaction between rheumatoid arthritis and pregnancy: correlation of molecular data with clinical disease activity measures

OBJECTIVE

The factors that induce remission of RA during pregnancy and the relapse occurring after delivery remain an enigma. In a previous study, we investigated gene-expression profiles of peripheral blood mononuclear cells (PBMC) in patients with RA and healthy women in late pregnancy and postpartum. Profiles of samples from both groups were similar in late pregnancy with elevated monocyte and decreased lymphocyte signatures. Postpartum, in RA PBMC the high level of monocyte transcripts persisted. Further increase was observed in adhesion, migration and signalling processes related to monocytes but also in lymphocytes despite similar clinical activity due to intensified drug treatment. This prompted us to investigate correlations between clinical parameters of disease activity and gene profiles.

METHODS

Transcriptome data were correlated with RADAI, CRP, monocyte and lymphocyte counts. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotations, monocytes and lymphocytes signatures were used as reference information.

RESULTS

Comparative analysis of PBMC expression profiles from RA patients during and after pregnancy with RADAI and CRP revealed a correlation of these disease activity parameters predominantly with monocyte transcripts. Genes related to cellular programs of adhesion, migration and response to infections were upregulated. Comparing clinically active and not-active RA patients postpartum revealed a cluster of 19 genes that could also identify active disease during pregnancy.

CONCLUSION

The data suggest that an increase of the RADAI and an elevation of CRP is a consequence of molecular activation of monocytes. Furthermore, they indicate that molecular activation of T lymphocytes may remain clinically unrecognized postpartum. It is conceivable that a set of 19 genes may qualify as molecular disease activity marker.

Human mastoid periosteum-derived stem cells: promising candidates for skeletal tissue engineering

Currently, mesenchymal stem cells (MSCs) are considered as the most eligible cells for skeletal tissue engineering. However, factors such as difficult stimulation and control of differentiation in vivo hamper their clinical use. In contrast, periosteum or periosteum-derived cells (PCs) are routinely clinically applied for bone and cartilage repair. PCs have often been named MSCs but, although cells of osteochondrogenic lineages arise from MSCs, it is unclear whether periosteum really contains MSCs. Our aim was to investigate the MSC-like character of PCs derived from the periosteum of mastoid bone. Harvesting of periosteum from mastoid bone is easy, so mastoid represents a good source for the isolation of PCs. Therefore, we analysed the MSC-like growth behaviour and the expression of embryonic, ectodermal, endodermal and mesodermal markers by microarray and FACS technology, and the multilineage developmental capacity of human PCs. Regarding clinical relevance, experiments were performed in human serum-supplemented medium. We show that PCs do not express early embryonic stem cell markers such as Oct4 and Nanog, or the marker of haematopoietic stem cells CD34, but express some other MSC markers. Osteogenesis resulted in the formation of calcified matrix, increased alkaline phosphatase activity, and induction of the osteogenic marker gene osteocalcin. Staining of proteoglycans and deposition of type II collagen documented chondrogenic development. As shown for the first time, adipogenic stimulation of mastoid-derived PCs resulted in the formation of lipid droplets and expression of the adipogenic marker genes aP2 and APM1. These results suggest MSC-like PCs from mastoid as candidates for therapy of complex skeletal defects.

Influence of peptidylarginine deiminase type 4 genotype and shared epitope on clinical characteristics and autoantibody profile of rheumatoid arthritis

BACKGROUND

Recent evidence suggests that distinction of subsets of rheumatoid arthritis (RA) depending on anti-cyclic citrullinated peptide antibody (anti-CCP) status may be helpful in distinguishing distinct aetiopathologies and in predicting the course of disease. HLA-DRB1 shared epitope (SE) and peptidylarginine deiminase type 4 (PADI4) genotype, both of which have been implicated in anti-CCP generation, are assumed to be associated with RA.

OBJECTIVES

To elucidate whether PADI4 affects the clinical characteristics of RA, and whether it would modulate the effect of anti-CCPs on clinical course. The combined effect of SE and PADI4 on autoantibody profile was also analysed.

METHODS

373 patients with RA were studied. SE, padi4_94C>T, rheumatoid factor, anti-CCPs and antinuclear antibodies (ANAs) were determined. Disease severity was characterised by cumulative therapy intensity classified into ordinal categories (CTI-1 to CTI-3) and by Steinbrocker score.

RESULTS

CTI was significantly associated with disease duration, erosive disease, disease activity score (DAS) 28 and anti-CCPs. The association of anti-CCPs with CTI was considerably influenced by padi4_94C>T genotype (C/C: OR(adj) = 0.93, p(adj) = 0.92; C/T: OR(adj) = 2.92, p(adj) = 0.093; T/T: OR(adj) = 15.3, p(adj) = 0.002). Carriage of padi4_94T exhibited a significant trend towards higher Steinbrocker scores in univariate and multivariate analyses. An association of padi4_94C>T with ANAs was observed, with noteworthy differences depending on SE status (SE-: OR(adj) = 6.20, p(adj)<0.04; SE+: OR(adj) = 0.36, p(adj) = 0.02) and significant heterogeneity between the two SE strata (p = 0.006).

CONCLUSIONS

PADI4 genotype in combination with anti-CCPs and SE modulates clinical and serological characteristics of RA.

[Expression analyses for rheumatoid arthritis]

Inflammatory rheumatic diseases with their unclear aetiology are a challenge for the routine clinical practice. The dominating inflammatory processes with many facets of autoimmune phenomena have been extensively studied during the last decades. Modern high throughput technologies provide for the first time the opportunity to obtain an insight into the many different molecular aspects in one patient in parallel. Step by step, concepts can be developed to understand the relationships and interdependencies of the molecular processes and to place them in order of importance for each individual separately. Thus, studies have demonstrated that the risk of disease severity can be estimated and the response to therapy can be objectified based on molecular investigations. Exemplarily, the potential has been demonstrated that the therapeutic outcome towards a defined treatment may be predicted. Despite the high cost, it is becoming more and more obvious that an extensive increase of knowledge depends on the detection of a multitude of parameters, a task which will need to be accomplished in the near future.

Functional, molecular and proteomic characterisation of bone marrow mesenchymal stem cells in rheumatoid arthritis

OBJECTIVE

Bone marrow (BM) mesenchymal stem cells (MSCs) are being considered as potential therapeutic agents in various inflammatory autoimmune diseases for their tissue-repair and anti-inflammatory tissue-protective properties. This study investigates the reserves and function, the molecular and proteomic profile and the differentiation potential of BM MSCs in patients with active rheumatoid arthritis (RA).

METHODS

We evaluated the frequency of MSCs in the BM mononuclear cell fraction using a limiting dilution assay, the proliferative/clonogenic potential and the capacity of cells to differentiate towards the osteogenic/chondrogenic/adipogenic lineages using appropriate culture conditions. We also assessed the molecular and proteomic characteristics in terms of inflammatory cytokine gene and protein expression, the relative telomere length and the survival characteristics of BM MSCs.

RESULTS

MSCs from patients with RA (n = 26) and age- and sex-matched healthy individuals (n = 21) were similar in frequency, differentiation potential, survival, immunophenotypic characteristics, and protein profile. Patient MSCs, however, had impaired clonogenic and proliferative potential in association with premature telomere length loss. Transcriptome analysis revealed differential expression of genes related to cell adhesion processes and cell cycle progression beyond the G1 phase. Previous treatment with methotrexate, corticosteroids, anti-cytokine and biological agents or other disease-modifying anti-inflammatory drugs did not correlate with the clonogenic and proliferative impairment of BM MSCs.

CONCLUSION

In spite of some restrictions related to the impaired clonogenic and proliferative potential, our findings support the use of autologous BM MSCs in RA and may have important implications for the ongoing efforts to repair tissue injury commonly seen in the course of the disease.

An oxygen imaging system for medical applications: preliminary results

The examination of functional processes in tissue is gaining importance in medical research. As a result the imaging and monitoring of biochemical parameters in vivo is the goal of many imaging methods. One key parameter in photodynamic therapy (PDT) is the molecular oxygen concentration. Two-dimensional monitoring of oxygen is demanded for PDT but has not yet been achieved. The use of optical methods provides a possible means of measuring molecular oxygen. The basis of this method is the measurement of the luminescence lifetime of a dye that is quenched by molecular oxygen. The molecular oxygen concentration can be monitored two-dimensionally by pixel-wise determination of the luminescence lifetime with a CCD-camera. A new O(2)-imaging system based on this principle is presented in this article. The dye Ru(bpy)(3)(2+) is quenched by molecular oxygen and was used in the first experiments with the system.

[Low-grade-/high-grade-synovitis: synovitis-score as a gold standard?]

BACKGROUND

Synovectomy specimens represent important material submitted from the orthopedist to the pathologist. However, no consistent histopathological grading system for chronic synovitis has been established so far.

PATIENTS AND METHODS

The three compartments of chronic synovitis (enlargement of lining cell layer, density of synovial stroma cells, leukocytic infiltrate) are graded semiquantitatively (from 0=absent to 3=strong), and the points for each compartment add up to the synovitis score: 0-1 = no synovitis, 2-4 = low-grade synovitis, 5-9 = high-grade synovitis. A total of 618 synovial specimens (resections n=559, biopsies n=59) from degenerative and inflammatory joint diseases were graded by two independent observers.

RESULTS

Median synovitis scores when correlated to clinical diagnoses were: 1, control; 2, osteoarthritis and post-traumatic arthritis; 3, psoriatic arthritis; 5, reactive and rheumatoid arthritis. The differences between rheumatic and non-rheumatic diseases were significant (p<0.001). The correlation between the two observers was high (p<0.001).

CONCLUSIONS

The proposed synovitis score enables stratification of chronic synovitis into low-grade (score 2-4) and high-grade (score >4), which is correlated to the nature of the disease (low-grade to non-rheumatic, high-grade to rheumatic), and it therefore contributes to the diagnosis of rheumatic and non-rheumatic joint diseases.

[Synovialitis score: histopathological grading system for chronic rheumatic and non-rheumatic synovialitis]

Standardization of the histopathological assessment of synovial membrane specimens might facilitate the diagnosis of chronic rheumatic and non-rheumatic joint diseases. We would like to propose a histological graduation scheme ("synovialitis score"), which is applicable to all forms of synovitis, irrespective of its etiology. This score evaluates the three compartments of chronic synovialitis [enlargement of lining cell layer, activation of synovial stroma (i. e. resident cells), leukocytic infiltrate] semiquantitatively (from 0=absent to 3=strong). Each compartment is graded separately, and the sum resembles the synovialitis score, which is interpreted as follows: 0-1: no synovialitis, 2- 3: slight synovialitis, 4-6: moderate synovialitis, 7-9: strong synovialitis (for sample photos see also www.charite.de/ch/patho/Webpage/pages/forschung/arbeitsgruppen/ag-krenn/index.htm). A total of 483 synovial specimens (resections n=462, biopsies n=21) were graded by two independent observers. Clinical diagnoses were osteoarthrosis (OA; n=153), posttraumatic arthritis (PtA; n=31), rheumatoid arthritis (RA; n=239), psoriatic arthritis (PsA; n=32), reactive arthritis (ReA; n=7), and controls (Co, n=21) from necropsies of patients without joint damage. The correlation between two observers was high (p<0.001). The correlation coefficient between the different samples from the same joint in n=112 cases was between 0.86 and 0.95. Median synovialitis scores when correlated with clinical diagnoses were: Co 0.5, OA 2, PtA 3, PsA 3, ReA 4, RA 5. The differences in scores between Co and all other groups were highly significant (p<0.001). A synovialitis score of 4 points and more was strongly associated with rheumatic joint diseases (sensitivity 73%, specificity 86%). Validation of the synovialitis score by gene expression data showed good correlations for the lining cell enlargement with MMP1 (0.685), for the leukocytic infiltrate with CD3 (0.754) and CD138 (0.744) and for the stroma activation with CD14 (0.744). The proposed synovialitis score is based on well definable histopathologic criteria and contributes to the diagnosis of rheumatic and non-rheumatic joint diseases.

Bone Morphogenetic Proteins im Skelettsystem—

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor-beta superfamily. Their potential for organ and tissue regeneration and repair has been intensively investigated in recent years. Studies on fetal development have demonstrated the important role of these proteins for the development and differentiation of different organs. Miss-expression or mutation of BMPs may lead to severe abnormalities or even abortion. However, a regenerative potential has also been recognized for the adult organism. BMPs support fracture healing and may contribute to treatment of joint diseases. Thus, BMP-7 is one of the first BMPs approved for clinical application in non-unions of bone fractures resistant to conventional therapy. In degenerative and inflammatory joint diseases, experimental data suggest a decrease of BMP expression in cartilage tissue. Therefore, BMPs could be promising therapeutic candidates in these diseases, although more detailed analyses are necessary. In this review we will focus on bone morphogenetic proteins and discuss present and putative future clinical applications.

[Tissue engineering: chances and challenges for application in rheumatic diseases]

Current technologies of tissue engineering offer new strategies for the treatment of cartilage and bone defects. Beyond implantation of cell suspensions, second generation products of biomaterial enforced with in vitro preformed tissues are clinically applied. Ongoing research and development focus on differentiation factors and tissue protection. In search for sources of autologous cells which are easier to collect and which may serve for more complex tissues like osteochondral implants, mesenchymal stem cells are investigated. The design of in vitro experiments, which are required for these investigations, has produced tissue engineering technologies, which may serve for pathophysiology research in inflammatory joint diseases and for exploration of treatment strategies. These together with the advances in biological therapies of rheumatic diseases are the basis of new concepts, which promise application of tissue engineering also in inflammatory joint diseases.

Shwartzman phenomenon in a patient with active systemic lupus erythematosus preceding fatal disseminated intravascular coagulation

The recurrence of widespread and diverse vascular lesions is a hallmark of systemic lupus erythematosus (SLE). Inflammatory and thrombotic mechanisms almost invariably associated with circulating antiphospholipid antibodies play a role in the pathogenesis of SLE-related vascular disease. Both mechanisms can coexist in the same patient. Vasculitis is most commonly induced by the local deposition of immune complexes. However, some SLE patients have an inflammatory complement-mediated vascular injury in the absence of immune complex deposition. We report on a fatal case of disseminated intravascular coagulation (DIC) in a young woman with active SLE. Hemorrhagic lesions due to localized intravascular coagulation (Shwartzman phenomenon) preceded disseminated intravascular coagulation accompanied by disseminated cardiac necrosis. Immune complex 'independent' and other mechanisms of vascular injury and states of hypercoagulability will be discussed.