Showing papers by "Ulf Müller-Ladner published in 2003"

Albumin-Based Drug Delivery as Novel Therapeutic Approach for Rheumatoid Arthritis

Abstract: We reported recently that albumin is a suitable drug carrier for targeted delivery of methotrexate (MTX) to tumors. Due to pathophysiological conditions in neoplastic tissue, high amounts of albumin accumulate in tumors and are metabolized by malignant cells. MTX, covalently coupled to human serum albumin (MTX-HSA) for cancer treatment, is currently being evaluated in phase II clinical trials. Because synovium of patients with rheumatoid arthritis (RA) shares various features observed also in tumors, albumin-based drug targeting of inflamed joints might be an attractive therapeutic approach. Therefore, the pharmacokinetics of albumin and MTX in a mouse model of arthritis was examined. Additionally, uptake of albumin by synovial fibroblasts of RA patients and the efficacy of MTX and MTX-HSA in arthritic mice were studied. The results show that when compared with MTX, significantly higher amounts of albumin accumulate in inflamed paws, and significantly lower amounts of albumin are found in the liver and the kidneys. The protein is metabolized by human synovial fibroblasts in vitro and in vivo. MTX-HSA was significantly more effective in suppression of the onset of arthritis in mice than was MTX. In conclusion, albumin appears to be a suitable drug carrier in RA, most likely due to effects on synovial fibroblasts, which might increase therapeutic efficacy and reduce side effects of MTX.

Albumin-based drug delivery as novel therapeutic approach for rheumatoid arthritis

Abstract: We reported recently that albumin is a suitable drug carrier for targeted delivery of methotrexate (MTX) to tumors. Due to pathophysiological conditions in neoplastic tissue, high amounts of albumin accumulate in tumors and are metabolized by malignant cells. MTX, covalently coupled to human serum albumin (MTX-HSA) for cancer treatment, is currently being evaluated in phase II clinical trials. Because the synovium of patients with rheumatoid arthritis (RA) shares various features observed also in tumors, albumin-based drug targeting of inflamed joints might be an attractive therapeutic approach. Therefore, the pharmacokinetics of albumin and MTX in a mouse model of arthritis was examined. Additionally, uptake of albumin by synovial fibroblasts of RA patients and the efficacy of MTX and MTX-HSA in arthritic mice were studied. The results show that, when compared with MTX, significantly higher amounts of albumin accumulate in inflamed paws, and significantly lower amounts of albumin are found in the liver and the kidneys. The protein is metabolized by human synovial fibroblasts in vitro and in vivo. MTX-HSA was significantly more effective in suppression of the onset of arthritis in mice than was MTX. In conclusion, albumin appears to be a suitable drug carrier in RA, most probably due to effects on synovial fibroblasts, which might increase the therapeutic efficacy of and reduce side effects of MTX.

p53 in rheumatoid arthritis synovial fibroblasts at sites of invasion

Abstract: Objective: To analyse the functional response of p53 in rheumatoid arthritis synovial fibroblasts (RASF) in vitro and in vivo and to investigate whether activation of p53 modulates the destructive process of RASF. Methods: RASF and controls grown on chamber slides were either directly examined with DO7 anti-p53 antibodies by immunofluorescence or irradiated with 10 Gy x rays and analysed time dependently for the expression of p53. The percentage of positive cells was evaluated by a quantitative scoring system. RASF and normal (N) SF cultured in vitro were co-implanted with human cartilage in SCID mice for 60 days. Consecutively, the invasion score was evaluated, and the number of p53 positive cells was determined at the sites of invasion by immunohistochemistry. In addition, synovial tissues from RA, osteoarthritis, and normal synovia were stained with DO7 antibodies. Results: In vitro the rate of expression of p53 in RASF was low (<5%), but transiently inducible by ionising irradiation (50%). In vitro low p53 expressing RASF disclosed, when invading articular cartilage, a nuclear p53 signal in 20% of the cells, indicating the induction of p53 in a distinct population of RASF during the invasive process. Conclusions: These data suggest an inductive p53 response at sites of cartilage invasion during the destructive process driven by activated RASF.

Laser-mediated microdissection facilitates analysis of area-specific gene expression in rheumatoid synovium.

Abstract: Objective Current approaches to analyzing gene expression in rheumatoid arthritis (RA) synovium are based on RNA isolated either from cultured synovial cells or from synovial biopsy specimens. This strategy does not, in general, allow distinction of specific gene expression between cells originating from different synovial areas, due to potential mixture of expression profiles. Therefore, we established the combination of laser-mediated microdissection (LMM) and differential display to analyze profiles of gene expression in histologically defined areas of rheumatoid synovium. The present study was undertaken to establish parameters for this technique and assess its usefulness for gene expression analysis. Methods Cryosections derived from RA synovial tissues were used to obtain cell samples from synovial lining versus sublining, using a microbeam laser microscope. RNA was isolated and analyzed by nested RNA arbitrarily primed–polymerase chain reaction (RAP-PCR) for differential display fingerprinting. Differentially expressed bands were cut out, and PCR products were eluted, cloned, and sequenced. Differential expression of identified sequences was confirmed by in situ hybridization and immunohistochemistry analysis. Results Microdissected sections of RA synovial tissue containing ∼600 cells yielded enough RNA to produce a reproducible RNA fingerprint pattern. Several genes could be identified as being expressed differentially between the synovial lining and the sublining, and their expression could be confirmed at the messenger RNA and protein levels. Conclusion The combination of LMM and RAP-PCR presents a valuable tool to obtain novel insights into the area-dependent differential regulation of gene expression in RA synovium. Both known and previously unknown genes were revealed with this technique. This study is the first to demonstrate the potential of this analytic strategy in the investigation of a nonmalignant, multifactorial, inflammatory disease.

The SCID mouse model: novel therapeutic targets – lessons from gene transfer

Abstract: The hallmark of rheumatoid arthritis (RA) is progressive destruction of the joints, preceded and accompanied by synovial hyperplasia and chronic inflammation. Spontaneous and induced animal models of RA reflect predominantly the inflammatory aspects of the disease. To reproduce the destruction of cartilage and bone mediated by an activated synovium, it was desirable to develop models that allow the dissection of cellular and molecular components derived from human tissue. The SCID mouse co-implantation model of human RA focuses on RA synovial fibroblasts (RA-SF) and their role in cartilage destruction. The model has provided the best evidence that RA-SF contribute significantly to matrix degradation, even in the absence of human lymphocytes and macrophages, since highly purified RA-SF invade the co-implanted normal human cartilage. Moreover, it became clear that they maintained their aggressive phenotype over long periods of time, particularly at sites of invasion into the co-implanted human cartilage. Targeting different signaling molecules, cytokines and matrix-degrading enzymes by soluble receptors, antagonists or negative mutants in the SCID mouse model of RA has implicated many of them in the mechanisms leading to cartilage destruction. However, since inhibition of a single molecule or pathway is not sufficient to inhibit the aggressive behavior of RA-SF it appears necessary to co-express in the synoviocytes genes for two or even more antagonists of e.g. cytokines, matrix-degrading enzymes or molecules interfering specifically with signaling pathways involved in the apoptosis of RA-SF. Based on the recent observation that the L1 (line-1) endogenous retroviral element appears responsible for the cytokine- independent activation via the MAPK p38delta, the current understanding of disease pathogenesis suggests that both the cytokine-dependent as well as the cytokine-independent pathways of joint destruction must be inhibited. Modulation of both pathways by gene transfer approaches in the SCID mouse model is a feasible method aimed at identifying novel targets for the prevention of cartilage destruction in RA.

Gene transfer as a future therapy for rheumatoid arthritis

Abstract: Inhibiting key pathogenic processes within the rheumatoid synovium is a most attractive goal to achieve, and the number of potential intra- and extracellular pathways operative in rheumatoid arthritis (RA) that could be used for a gene therapy strategy is increasing continuously. Gene transfer or gene therapy might also be one of the approaches to solve the problem of long-term expression of therapeutic genes, in order to replace the frequent application of recombinant proteins, in the future. However, at present, gene therapy has not reached a realistic clinical stage, which is mainly due to severe side effects in humans, the complexity of RA pathophysiology and the current state of available gene transfer techniques. On the other hand, novel gene delivery systems are not restricted to vectors or certain types of cells, as mobile cells including macrophages, dendritic cells, lymphocytes and multipotent stem cells can also be used as smart gene transfer vehicles. Moreover, the observation in animal models that application of viral vectors into a joint can exert additional therapeutic effects in nearby joints might also facilitate the transfer from animal to human gene therapy. Future strategies will also examine the potential of novel long-term expression vectors such as lentiviruses and cytomegalovirus (CMV)-based viruses as a basis for future clinical trials in RA.

Fatal outcome of constrictive pericarditis in rheumatoid arthritis

Abstract: This is a report of a 39-year-old patient diagnosed with seropositive rheumatoid arthritis at the age of 17. The patient died 2 years after the onset of extra-articular cardiac symptoms. This case demonstrates the devastating course of progressive constrictive pericarditis under sole medical therapy and emphasizes the importance of early radical pericardectomy to avoid progression of disease and secondary complications with fatal outcome. Further, we discuss risk factors, diagnostic caveats, diagnostic tests and therapy of hemodynamically relevant contrictive pericarditis.

Molekulare Bildgebung bei rheumatoider Arthritis

Abstract: Mit den Fortschritten der Molekularbiologie und den technischen Entwicklungen auf dem Gebiet der Bildgebung wird es zunehmend moglich, biologische Prozesse nichtinvasiv auf molekularer Ebene sichtbar zu machen und quantitativ zu erfassen. Diese Technologie, die mit dem Begriff molekulare Bildgebung beschrieben wird, basiert auf sogenannten “molekularen Markern“ und soll eine fruhe Diagnose, eine verbesserte Klassizifierung von Stadium und Schwere von Erkrankung, eine objektive Beurteilung des Behandlungserfolges und eine zuverlassige Prognose des Patienten ermoglichen. Daruber hinaus ist die molekulare Bildgebung ein wertvolles Werkzeug fur die Evaluierung physiologischer und pathophysiologischer Prozesse sowie fur die Entwicklung von Medikamenten. Mit der konventionellen Radiographie (CR), der Computertomographie (CT), nuklearmedizinischen Methoden, der Magnetresonanztomographie (MRT), der Sonographie (US) und anderen Verfahren wie der fluoreszenzoptischen Bildgebung, stehen eine Reihe von bildgebenden Systemen zur Verfugung, die sich hinsichtlich der Auflosung und der Moglichkeiten, Informationen auf anatomischer, physiologischer, zelluarer und molekularer Ebene zu erhalten, unterscheiden. Damit hangt die Auswahl des bildgebenden Verfahrens fur die molekulare Bildgebung im Einzelfall von der Fragestellung ab. Die vorliegende Ubersicht diskutiert das Potential bildgebender Verfahren fur die molekulare Bildgebung bei der rheumatoiden Arthritis (RA).

Molecular imaging in rheumatoid arthritis

Abstract: Advances in molecular biology and technical developments in the field of imaging are increasingly allowing for non-invasive visualization and quantitation of biological processes at the molecular level. Such technologies, defined as molecular imaging, promise early diagnosis and improved classification of the stage and severity of disease, objective assessment of treatment efficacy, and reliable prognosis based on so-called molecular markers. Furthermore, molecular imaging is an important tool for the evaluation of physiological and pathophysiological processes and for drug development. Various different imaging modalities are available, such as conventional radiography (CR), computed tomography (CT), nuclear imaging, magnetic resonance imaging (MRI), ultrasound (US), as well as other methods including fluorescence-based optical imaging. These methods differ with respect to resolution and their potential to gather information at the anatomical, physiological, cellular and molecular level. Therefore, the choice of the imaging modality for molecular imaging depends on the questions that need to be answered. This review discusses the potential of imaging modalities for molecular imaging in rheumatoid arthritis (RA).

Getting scientists together: the ACR/EULAR exchange programme

Abstract: Many of the landmark discoveries in biomedical science were based on individual brilliance and talent. However, over the years it became apparent that the pathogenesis of various diseases, and of autoimmune disorders in particular, is complex and requires a multidisciplinary approach. For example, the search for disease susceptibility genes in human diseases demands intensive collaboration between clinicians, geneticists, molecular biologists, and biostatisticians. Furthermore, the technological revolution in the field of biomedical research requires international collaboration to exchange the necessary expertise. International meetings, although very useful for the scientific community, have their limitations. By their nature, such meetings can increase subspecialisation and in overview sessions the large numbers of participants may be counterproductive for personal contact. This can be a particular barrier to younger members of the scientific community who wish to get involved with other groups. However, it will fall to these young scientists to strengthen the network to target diseases. Despite many similarities among scientific groups on either side, the Atlantic Ocean has proved to be a major barrier to such effort. Meeting the demand for a forum for young rheumatologists, the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) established an exchange programme in 1997 between European and American scientists in the field of rheumatology. The first exchange took place in 1998. Since then each year, three junior academic scientists accompanied by one senior rheumatologist of ACR and EULAR, respectively, travel across the ocean to visit academic centres for a …

Immunologisch bedingte Krankheiten

Abstract: Bei den primaren Immundefekten handelt es sich vorwiegend um sehr seltene Erkrankungen, deren Inzidenz vielfach in der Grosenordnung von 1:1.000.000 oder darunter liegt. Das Management dieser Patienten erfordert daher die enge Zusammenarbeit zwischen dem betreuenden Haus- oder Kinderarzt, Arzten aus immunologischen Schwerpunktzentren sowie weiteren Facharzten wie z. B. Dermatologen, Pulmonologen und Gastroenterologen. Die Therapieeinleitung wird in immunologischen Schwerpunktzentren begonnen, in denen die Patienten auch in regelmasigen Abstanden vorstellig werden sollten.