Detection of annexin A8 antibodies in serum of patients with antiphospholipid syndrome

Introduction: Antibodies specific for annexin A8 (AnxA8) have not been investigated in patients suffering from antiphospholipid syndrome (APS) yet. The aim of this study was to compare the presence of AnxA8 antibodies in serum of APS patients with that of age-matched healthy controls and to investigate whether AnxA8 antibodies are potential biomarkers for APS. Materials and methods: We enrolled 22 APS patients and 22 healthy controls in this case-control study. We used sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblot to investigate the presence of AnxA8 antibodies, and we applied enzyme-linked immunosorbent assay to investigate the presence of cardiolipin (CL) and beta-2-glycoprotein I (ß2GPI) antibodies. Results: The serum of 9/22 APS patients showed AnxA8 IgG isotype antibody reactivity compared to serum of 2/22 healthy controls (P = 0.034). When we also included weak immunoblot signals, 12/22 APS patients exhibited AnxA8 IgG isotype antibody reactivity compared to 3/22 healthy controls (P = 0.005). We also investigated the presence of AnxA8 IgM isotype antibodies in the serum of APS patients but found no statistically significant difference between the APS patient group and healthy control group (P = 0.500). We further investigated the presence of ß2GPI and CL IgG and IgM isotype antibodies. AnxA8 IgG isotype antibodies were present in APS patients in a similar frequency as the APS “criteria” antibody against CL (P = 0.764). Conclusion: We demonstrated that AnxA8 IgG isotype antibodies are potential biomarkers for the diagnosis of APS

Chondrozyten-COMP-Interaktionen im Rahmen der Knorpeldegradation – Bedeutung für die Knorpelhomöostase & Identifizierung Arthrose-assoziierter Antikörper: Definition einer autoimmun-Arthrose anhand neuer serologischer Biomarker?

Der erste Teil meiner Dissertation beschäftigt sich mit dem Einfluss von Cartilage-Oligomeric- Matrix-Protein (COMP) auf die differentielle Genexpression von humanen Chondrozyten. Hierfür wurden humane Chondrozyten und Knorpelexplantate mit COMP und/oder TGF-β stimuliert und die Expression proinflammatorischer Zytokine und MMPs (IL-6, MMP1, MMP13) sowie die Induktion von Wachstumsfaktoren (TGF-β und BMP-2) und extrazellulären Matrixmolekülen (Kollagen I, Kollagen II, Kollagen X) untersucht. Die untersuchten Proteine spielen eine Rolle in der Pathophysiologie der Arthrose und in der Chondrozytendifferenzierung. COMP allein nahm keinen unmittelbaren Einfluss auf die differenzielle Genexpression von Chondrozyten. Die Kostimulation von Chondrozyten mit COMP und TGF-β führte jedoch zu einer stärkeren IL-6 Freisetzung als die Stimulation mit TGF-β allein. Somit konnte eine kooperative Wirkung von COMP und TGF-β an humanen Chondrozyten nachgewiesen werden. Wird die veränderte TGF-β-Signaltransduktion bei einer Arthrose berücksichtigt, könnte COMP somit zu einer Verstärkung der TGF-β-abhängigen Prozesse im Rahmen einer Arthrose führen. Der zweite Teil meiner Dissertation beschäftigt sich mit der Frage nach der Existenz von Arthrose-assoziierten Antikörpern. Insbesondere wurde untersucht, ob Antikörper gegen die extrazellulären Matrixproteine Matrilin-3, Kollagen II, Kollagen VI, Fibrillin-2, CLEC3A, Tetranectin, Thrombospondin-4 und COMP im Rahmen einer Arthrose nachgewiesen werden können. Für den Antikörpernachweis wurden die oben genannten Proteine mittels Immunoblot unter der Verwendung von PatientInnenseren als Erstantikörper und Antihumanglobulin als Zweitantikörper untersucht. Insgesamt fand sich eine erhöhte Prävalenz von Autoantikörpern gegen TSP-4, COMP und CLEC3A im Serum von PatientInnen mit einer Arthrose im Vergleich zu gesunden ProbandInnen. Somit könnte der Nachweis von Autoantikörpern gegen TSP-4, COMP und CLEC3A die Diagnose einer Arthrose unterstützen und einen autoimmunen bzw. Autoantikörper-assoziierten Arthrosesubtyp identifizieren. Bei PatientInnen mit einer autoimmunen Arthrose könnten immunmodulatorische/immunsuppressive Therapien erfolgreich sein

Reliability of a radiation-free, noninvasive and computer-assisted assessment of the spine in children with cerebral palsy

Purpose The radiation-free, noninvasive and computer-assisted Spinal Mouse(R) (SM) is a reliable and valid measuring instrument for functional analysis of the pediatric spine. The aim of this study was to examine the intra-rater reliability of the SM measurements in children with cerebral palsy (CP) and to investigate differences after a 1 week of the rehabilitation program. Methods A total of 168 SM investigations in the sagittal plane and frontal plane at three measurement times from a sample of 28 children (n = 10 girls, age 9.7 +/- 3.1 years) with CP were eligible for evaluation. For the verification of reliability, the measurement results from the first and second measurement times (t1, t2) were used at intervals of 1 day. In addition, differences after the rehabilitation program the patients underwent (t3) were evaluated using the measurement results of the first and third measurements (5-day interval). Results The results show good to excellent intra-rater reliability for the SM measurements, both in the sagittal and in the frontal plane (ICC values = 0.69-0.99). Furthermore, significant changes may occur after only 1 week of therapeutic intervention for total spinal inclination (t1: 12.82 +/- 5.40, t3: 11.11 +/- 5.60, p = 0.014, Cohen's d = 0.43) and spine length (t1: 401.75 +/- 69.05, t3: 409.25 +/- 63.58, p = 0.030, Cohen's d = 0.43). Conclusions SM can be used to generate reliable values for functional analysis of the spine in children with CP. Furthermore, significant posture differences can be demonstrated by therapeutic interventions, especially in the spine inclination (Inc) and spine length (SL). Graphic abstract These slides can be retrieved under Electronic Supplementary Material

COMP does not directly modify the expression of genes involved in cartilage homeostasis in contrast to several other cartilage matrix proteins

Objective: We investigated whether COMP may modify cartilage metabolism and play a role as an endogenous disease aggravating factor in OA. Materials and methods: Full-length and momomeric COMP was recombinantly expressed in human embryonic kidney cells and purified it via affinity chromatography. Purified COMP was used to stimulate either primary human chondrocytes or cartilage explants. Changes in the expression profiles of inflammatory genes, differentiation markers and growth factors were examined by immunoassay and by quantitative real-time reverse-transcription polymerase chain reaction. Results: Incubation of primary human chondrocytes or cartilage explants in the presence of COMP did not induce statistically significant changes in the expression of IL-6, MMP1, MMP13, collagen I, collagen II, collagen X, TGF-beta 1 and BMP-2. Conclusions: In contrast to collagen II and matrilin-3, COMP lacks the ability to trigger a proinflammatory response in chondrocytes, although it carries an RGD motif and can bind to integrins. COMP is a well-accepted biomarker for osteoarthritis but increased COMP levels do not necessarily correlate with inflammation

Identification of antibodies against extracellular matrix proteins in human osteoarthritis

We investigated the presence of autoantibodies against the extracellular matrix proteins thrombospondin-4 (TSP-4), cartilage oligomeric matrix protein (COMP), C-type lectin domain family 3 member A (CLEC3A), collagen II, collagen VI, matrilin-3, and fibrillin-2 in the serum of osteoarthritis (OA) patients. We compared those results with the presence of such antibodies in rheumatoid arthritis (RA) patients and in healthy donors (HD). Our study examines whether antibodies against extracellular proteins can be used as potential biomarkers to support the clinical diagnosis of OA. 10 OA, 10 RA patients and 10 HD were enrolled in this explorative cross-sectional study. SDS-PAGE and immunoblot were used to investigate the presence of antibodies against extracellular matrix proteins. The serum of 5/10 OA patients but 0/10 HD exhibited TSP-4 IgG isotype antibodies (P = 0.033). The serum of 8/10 OA patients but only 1/10 HD exhibited IgG isotype antibodies against TSP-4 or COMP (P = 0.005). The serum of 9/10 OA patients but only 1/10 HD exhibited IgG isotype antibodies against TSP-4, COMP or CLEC3A (P = 0.005). We found strong evidence for the presence of IgG isotype autoantibodies against the cartilage extracellular matrix proteins TSP-4, COMP and CLEC3A in OA. The detection of IgG isotype autoantibodies against TSP-4, COMP and CLEC3A may support the clinical diagnosis of OA. OA with autoantibodies against cartilage extracellular matrix proteins defines a new OA subgroup suggesting that patients with high concentrations of autoantibodies may benefit from an immune suppressive therapy. (C) 2018 Elsevier Inc. All rights reserved