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Biomedical subjects

Cem Gabay

Publications and source records attributed to Cem Gabay.

At least 19 recordsLinked to original sources
PubMed2026

A Multifaceted Interplay Among Hemophagocytosis, Interleukin-18, and Type I Interferon Distinguishes Still Disease From Other Autoinflammatory Diseases.

OBJECTIVE: The unknown pathophysiology and the lack of specific features for systemic juvenile idiopathic arthritis and adult-onset Still disease (collectively known as Still disease; SD) delay diagnosis and appropriate treatment. The goal of this study was to identify features and mechanisms that distinguish SD from other systemic autoinflammatory diseases (SAID). METHODS: Using the SomaScan assay and RNA sequencing (RNA-Seq), we determined the plasma proteomes and immune cell microRNA (miRNA) and RNA transcriptomes of 372 patients with SAID, respectively. Proteomic findings were validated by enzyme-linked immunosorbent assays. SD (n = 72) and non-SD SAIDs (n = 300) were compared to identify distinguishing features of SD. We performed integrated and unbiased analyses of all data sets using weighted gene correlation network analysis to identify feature modules that characterize SD and stratify patients. RESULTS: Elevated plasma heme oxygenase 1 (HO-1) and interleukin-18 (IL-18) strongly correlate and characterize SD but do not associate with general inflammation. SD was characterized by ferroptosis in plasma, type I interferon (IFN) signaling in monocyte transcriptomes, and elevated natural killer cell miRNA-146a-5p, which is an IL-18 induced miRNA. Finally, we identified feature modules that distinguish SD from other SAIDs and stratified patients with SD into two distinct subgroups not attributable to disease activity or inflammation but hemophagocytosis. CONCLUSION: This unprecedented large omics data set of SAIDs revealed that complex interactions among hemophagocytosis, IL-18, and type I IFN signaling characterize SD. Furthermore, two distinct subgroups in patients with SD were distinguished by the degree of hemophagocytic activity. Finally, the large proteomics and RNA-Seq data sets generated in this study can serve as an invaluable resource for the further investigation of SD and other SAIDs.

Humans↗
PubMed2006

Indirect effects of leptin receptor deficiency on lymphocyte populations and immune response in db/db mice.

Leptin-deficient ob/ob and leptin receptor (Ob-rb)-deficient db/db mice display a marked thymic atrophy and exhibit defective immune responses. Lymphocytes express leptin receptors and leptin exerts direct effects on T cells in vitro. In addition, ob/ob and db/db mice display multiple neuroendocrine and metabolic defects, through which leptin deficiency may indirectly affect the immune system in vivo. To study the relative contributions of direct and indirect effects of leptin on the immune system in a normal environment, we generated bone marrow chimeras (BMCs) by transplantation of leptin receptor-deficient db/db, or control db/+, bone marrow cells into wild-type (WT) recipients. The size and cellularity of the thymus, as well as cellular and humoral immune responses, were similar in db/db to WT and db/+ to WT BMCs. The immune phenotype of db/db mice is thus not explained by a cell autonomous defect of db/db lymphocytes. Conversely, thymus weight and cell number were decreased in the reverse graft setting in WT to db/db BMCs, indicating that expression of the leptin receptor in the environment is important for T cell development. Finally, normal thymocyte development occurred in fetal db/db thymi transplanted into WT hosts, indicating that direct effects of leptin are not required locally in the thymic microenvironment. In conclusion, direct effects of leptin on bone marrow-derived cells and on thymic stromal cells are not necessary for T lymphocyte maturation in normal mice. In contrast, leptin receptor deficiency affects the immune system indirectly via changes in the systemic environment.

Animals↗
PubMed2006

Interleukin-6 and chronic inflammation.

Interleukin (IL)-6 is produced at the site of inflammation and plays a key role in the acute phase response as defined by a variety of clinical and biological features such as the production of acute phase proteins. IL-6 in combination with its soluble receptor sIL-6Ralpha, dictates the transition from acute to chonic inflammation by changing the nature of leucocyte infiltrate (from polymorphonuclear neutrophils to monocyte/macrophages). In addition, IL-6 exerts stimulatory effects on T- and B-cells, thus favoring chronic inflammatory responses. Strategies targeting IL-6 and IL-6 signaling led to effective prevention and treatment of models of rheumatoid arthritis and other chronic inflammatory diseases.

Acute-Phase Proteins↗
PubMed2006

The new IL-1 family member IL-1F8 stimulates production of inflammatory mediators by synovial fibroblasts and articular chondrocytes.

Six novel members of the IL-1 family of cytokines were recently identified, primarily through the use of DNA database searches for IL-1 homologues, and were named IL-1F5 to IL-1F10. In the present study, we investigated the effect of IL-1F8 on primary human joint cells, and examined the expression of the new IL-1 family members in human and mouse joints. Human synovial fibroblasts (hSFs) and human articular chondrocytes (hACs) expressed the IL-1F8 receptor (IL-1Rrp2) and produced pro-inflammatory mediators in response to recombinant IL-1F8. IL-1F8 mRNA expression was increased in hSFs upon stimulation with proinflammatory cytokines, whereas in hACs IL-1F8 mRNA expression was constitutive. However, IL-1F8 protein was undetectable in hSF and hAC culture supernatants. Furthermore, although IL-1beta protein levels were increased in inflamed human and mouse joint tissue, IL-1F8 protein levels were not. IL-1F8 levels in synovial fluids were similar to or lower than those in matched serum samples, suggesting that the joint itself is not a major source of IL-1F8. Serum levels of IL-1F8 were similar in healthy donors, and patients with rheumatoid arthritis, osteoarthritis and septic shock, and did not correlate with inflammatory status. Interestingly however, we observed high IL-1F8 levels in several serum samples in all groups. In conclusion, IL-1F8 exerts proinflammatory effects in primary human joint cells. Joint and serum IL-1F8 protein levels did not correlate with inflammation, but they were high in some human serum samples tested, including samples from patients with rheumatoid arthritis. It remains to be determined whether circulating IL-1F8 can contribute to joint inflammation in rheumatoid arthritis.

Animals↗
PubMed2006

[Septic arthritis].

Septic arthritis is a medical emergency that may be associated with significant mortality (10-15%) and morbidity (25-50%), in case of delayed management. When septic arthritis is suspected, arthrocentesis and culture of the synovial fluid are the gold standard. The absence of fever, rigors, leukocytosis or elevated erythrocyte sedimentation rate does not exclude the diagnosis of septic arthritis. Age, chronic arthropathy, or arthroplasty are particularly associated with increased morbidity. Therapy consists in antibiotics, joint immobilisation (maximum 3 days) and medical drainage, in case of persisting joint effusion.

Anti-Bacterial Agents↗
PubMed2006

The effectiveness of anti-tumor necrosis factor therapy in preventing progressive radiographic joint damage in rheumatoid arthritis: a population-based study.

OBJECTIVE: To compare the effectiveness of 3 therapeutic strategies in preventing progressive joint damage, in a population-based cohort. The 3 strategies were infliximab with concomitant disease-modifying antirheumatic drugs (DMARDs), etanercept with concomitant DMARDs, and etanercept alone. METHODS: We used sequential radiographs to assess all patients who were treated with infliximab or etanercept for >10 months. The rates of erosion progression and joint space narrowing (JSN) were analyzed using multivariate regression models for longitudinal data, with adjustment for potential confounders. RESULTS: A total of 372 patients treated with anti-tumor necrosis factor (TNF) therapies met the inclusion criteria. The baseline characteristics of the patients assigned to the 3 strategies were not significantly different, except that, as expected, more patients were receiving combination therapy with infliximab. The combination of infliximab plus DMARDs was significantly more effective than etanercept alone for controlling erosion progression (P < 0.001), but the effectiveness of the 2 combination-treatment strategies was similar (P = 0.07). The combination of infliximab plus DMARDs was also more effective at controlling progressive JSN compared with etanercept alone (P = 0.04) or etanercept plus DMARDs (P = 0.02). Treatment with anti-TNF agents (infliximab or etanercept) plus concomitant DMARDs was more effective than treatment with etanercept alone for controlling erosion progression (P = 0.045). CONCLUSION: When combined with traditional DMARDs, both etanercept and infliximab appear to offer similar protection against progressive structural joint damage, and combination therapy with either of these agents appears to be more effective than treatment with etanercept alone.

Adult↗
PubMed2006

Is IL-1 a good therapeutic target in the treatment of arthritis?

Inflammation is an important homeostatic mechanism that limits the effects of infectious agents. However, inflammation might be self-damaging and therefore has to be tightly controlled or even abolished by the organism. Interleukin 1 (IL-1) is a crucial mediator of the inflammatory response, playing an important part in the body's natural responses and the development of pathological conditions leading to chronic inflammation. While IL-1 production may be decreased or its effects limited by so-called anti-inflammatory cytokines, in vitro IL-1 inflammatory effects are inhibited and can be abolished by one particularly powerful inhibitor, IL-1 receptor antagonist (IL-1Ra). Recent research has shown that in the processes of rheumatoid arthritis (RA) IL-1 is one of the pivotal cytokines in initiating disease, and IL-1Ra has been shown conclusively to block its effects. In laboratory and animal studies the inhibition of IL-1 by either antibodies to IL-1 or IL-1Ra proved beneficial to the outcome. Because of its beneficial effects in many animal disease models, IL-1Ra has been used as a therapeutic agent in human patients. The recombinant form of IL-1Ra, anakinra (Kineret, Amgen) failed to show beneficial effects in septic shock and displays weak effects in RA patients. However, IL-1 blockade by anakinra is dramatically effective in systemic-onset juvenile idiopathic arthritis, in adult Still's disease and in several autoinflammatory disorders, most of the latter being caused by mutations of proteins controlling IL-1beta secretion. Importantly, to be efficacious, anakinra required daily injections, suggesting that administered IL-1Ra displays very short-term effects. Better IL-1 antagonists are in the process of being developed.

Animals↗
PubMed2006

Systemic rheumatoid vasculitis: a review.

OBJECTIVES: To review the most recent information on the incidence, clinical course, pathology, pathogenesis, diagnosis, and treatment of rheumatoid vasculitis (RV), including the still scanty data on the use of biologics. METHODS: PubMed and MEDLINE databases (1950-2006) were searched for the key words "vasculitis" and "rheumatoid arthritis"; and "rheumatoid arthritis" and "extra-articular manifestations." All relevant articles in English and French were reviewed. Additional words used in follow-up research include "anti-TNF," "rituximab," "IL-1 receptor antagonists," and "CTLA-4 Ig," all in conjunction with "vasculitis." Pertinent secondary references were also retrieved. RESULTS: RV is an inflammatory condition of the small- and medium-sized vessels that affects a subset of patients with established rheumatoid arthritis (RA) (approximately 1 to approximately 5%). It has a vast array of clinical manifestations with a predilection for the skin (peripheral gangrene, deep cutaneous ulcers) and the peripheral nervous system (mononeuritis multiplex). Because of the lack of specific signs and symptoms, the diagnosis relies on the exclusion of other causes of similar lesions (diabetes, atherosclerosis, drug reactions, infection, neoplasias) and, ideally, on the histopathological demonstration of necrotizing vasculitis. Despite the availability of a host of promising new drugs for the treatment of RA, no clinical trials have tested their efficacy in RV; therefore, its management remains largely empirical. CONCLUSIONS: Although RV has apparently been decreasing over the last 2 decades, possibly as a consequence of the more energetic approach to the management of RA currently used, it remains an important complication of RA that needs to be promptly recognized and treated.

Arthritis, Rheumatoid↗
PubMed2006

The role of IL-1 and IL-1Ra in joint inflammation and cartilage degradation.

Interleukin (IL)-1 is a cytokine that plays a major role in inflammatory responses in the context of infections and immune-mediated diseases. IL-1 refers to two different cytokines, termed IL-1alpha and IL-1beta, produced from two genes. IL-1alpha and IL-1beta are produced by different cell types following stimulation by bacterial products, cytokines, and immune complexes. Monocytes/macrophages are the primary source of IL-1beta. Both cytokines do not possess leader peptide sequences and do not follow a classical secretory pathway. IL-1alpha is mainly cell associated, whereas IL-1beta can be released from activated cells after cleavage of its amino-terminal region by caspase-1. IL-1 is present in the synovial tissue and fluids of patients with rheumatoid arthritis. Several in vitro studies have shown that IL-1 stimulates the production of mediators such as prostaglandin E(2), nitric oxide, cytokines, chemokines, and adhesion molecules that are involved in articular inflammation. Furthermore, IL-1 stimulates the synthesis and activity of matrix metalloproteinases and other enzymes involved in cartilage destruction in rheumatoid arthritis and osteoarthritis. The effects of IL-1 are inhibited in vitro and in vivo by natural inhibitors such as IL-1 receptor antagonist and soluble receptors. IL-1 receptor antagonist belongs to the IL-1 family of cytokines and binds to IL-1 receptors but does not induce any intracellular response. IL-1 receptor antagonist inhibits the effect of IL-1 by blocking its interaction with cell surface receptors. The use of IL-1 inhibitors in experimental models of inflammatory arthritis and osteoarthritis has provided a strong support for the role of IL-1 in the pathogeny of these diseases. Most importantly, these findings have been confirmed in clinical trials in patients with rheumatic diseases. Additional strategies aimed to block the effect of IL-1 are tested in clinical trials.

Animals↗
PubMed2006

The role of leptin in innate and adaptive immune responses.

Leptin is produced primarily by adipocytes and functions in a feedback loop regulating body weight. Leptin deficiency results in severe obesity and a variety of endocrine abnormalities in animals and humans. Several studies indicated that leptin plays an important role in immune responses. It exerts protective anti-inflammatory effects in models of acute inflammation and during activation of innate immune responses. In contrast, leptin stimulates T lymphocyte responses, thus having rather a proinflammatory role in experimental models of autoimmune diseases. Clinical studies have so far yielded inconsistent results, suggesting a rather complex role for leptin in immune-mediated inflammatory conditions in humans.

Animals↗
PubMed2005

Clinical evaluation of a cohort of patients with rheumatoid arthritis treated with anti-TNF-alpha in the community.

OBJECTIVES: TNF-alpha inhibitors have been effective in randomized controlled studies for the treatment of RA. The purpose of this study was to evaluate the clinical, laboratory, and radiological responses in a cohort of unselected patients with RA treated with TNF-alpha inhibitors in the community. METHODS: Using the Swiss Clinical Quality Management in Rheumatoid Arthritis, a centralized system of data gathering for RA patients, we obtained the following information regarding patients treated with a TNF-alpha inhibitor in the Geneva Canton before 02/2003: demographics; clinical data (disease activity, functional status, treatments received and type of TNF-alpha inhibitor used); laboratory and radiographic data. RESULTS: A total of 66 patients (mean age = 60.5 years) with long-standing disease (mean duration = 12.5 years) were analyzed. Sixteen patients (24%) discontinued anti-TNF-alpha, half within the first 6 months of the study. Mean DAS score decreased from 4.8+ /- 0.4 to 3.8 +/- 0.4 (P < 0.01); HAQ scores (mean = 1.35) remained unchanged; pain, evaluated on a 10-point scale, decreased from 5.0 at baseline to 3.3 (P < 0.001). CRP values decreased steadily from 17.9 at baseline to 5.6 at 20 months or later. The progression of radiographic damage decelerated in 30 patients, accelerated in 12, and remained unchanged in one. CONCLUSIONS: The responses of this community-based group of patients with severe, long-standing RA to TNF-alpha inhibitors revealed a reassuring similarity to those of patients enrolled in controlled clinical trials.

Adult↗
PubMed2005

Intracellular interleukin-1 receptor antagonist type 1 antagonizes the stimulatory effect of interleukin-1 alpha precursor on cell motility.

Interleukin (IL)-1alpha, a proinflammatory cytokine, is produced as a 33 kDa protein precursor (preIL-1alpha) which is cleaved to generate the 17 kDa C-terminal mature IL-1alpha (mIL-1alpha) and the 16kDa N-terminal IL-1alpha propiece (NIL-1alpha). The biological effect of IL-1alpha is regulated by the IL-1 receptor antagonist (IL-1Ra), its naturally occurring inhibitor. Four different isoforms of the IL-1Ra have been described, one secreted (sIL-1Ra) and three intracellular (icIL-1Ra1, 2, 3). Whether the icIL-1Ra1 isoform can antagonize some of the biological effects of intracellular IL-1alpha is still unknown. The aim of this study is to investigate effects of preIL-1alpha and icIL-1Ra1 on cell motility in stably transfected ECV304 cells. We show that expression of preIL-1alpha in ECV304 cells significantly increases cell motility. Furthermore, transfection with NIL-1alpha propiece also increases cell motility whereas this stimulatory effect was not observed by addition of exogenous mIL-1alpha, suggesting an intracellular effect of preIL-1alpha mediated by NIL-1alpha propiece. Co-transfection of ECV304 cells with icIL-1Ra1 completely antagonizes the stimulatory effect of preIL-1alpha and NIL-1alpha propiece on cell motility. In conclusion, NIL-1alpha propiece increases ECV304 cell motility and icIL-1Ra1 exerts intracellular functions regulating this stimulatory effect.

Cell Line, Tumor↗
PubMed2005

Pre-interleukin-1alpha expression reduces cell growth and increases interleukin-6 production in SaOS-2 osteosarcoma cells: Differential inhibitory effect of interleukin-1 receptor antagonist (icIL-1Ra1).

Interleukin-1 receptor antagonist (IL-1Ra) inhibits the classical biological effects of interleukin (IL)-1 by preventing its binding to IL-1 receptors. There are, however, four different isoforms of IL-1Ra, of which three are intracellular (icIL-1Ra1, 2, 3). Due to their localization, icIL-1Ras cannot interact with cell surface IL-1 receptors and have been suggested to carry out specific functions inside cells. The recent description of nuclear effects of the IL-1alpha precursor (preIL-1alpha) led to the hypothesis that icIL-1Ra variants might antagonize the intracellular actions of preIL-1alpha. The aim of this study was to investigate effects of preIL-1alpha and icIL-1Ra1 in stably transfected SaOS-2 cells. Expression of preIL-1alpha significantly decreased cell growth and this effect was not reversed by addition of exogenous IL-1Ra, suggesting an intracellular mode of action. Transfection of SaOS-2 cells with icIL-1Ra1 did not affect their growth. Furthermore, co-expression of icIL-1Ra1 did not reverse the growth inhibitory effect of preIL-1alpha. In contrast, the production of IL-6 induced by preIL-1alpha was decreased in icIL-1Ra1 co-transfected cells. In conclusion, expression of preIL-1alpha decreased the growth of SaOS-2 cells, likely by an intracellular mechanism. Co-expression of icIL-1Ra1 did not antagonize this effect, indicating that intracellular effects of preIL-1alpha are not necessarily susceptible to inhibition by icIL-1Ra1.

Cell Division↗
PubMed2005

Interleukin-1 plays a major role in vascular inflammation and atherosclerosis in male apolipoprotein E-knockout mice.

OBJECTIVE: To examine the role of the balance between interleukin (IL)-1 and IL-1 receptor antagonist (IL-1Ra) in atherosclerosis and vascular inflammation. METHODS: Transgenic (Tg) mice overexpressing either secreted IL-1Ra or intracellular IL-1Ra1 as well as IL-1Ra-deficient mice (IL-1Ra -/-) were crossed with apolipoprotein E-deficient mice (ApoE -/-). RESULTS: In males fed a cholesterol-rich diet for 10 weeks, average atherosclerotic lesion area within aortic roots was significantly decreased in ApoE -/- secreted IL-1Ra Tg (-47%) and ApoE -/- intracellular IL-1Ra1 Tg (-40%) mice as compared to ApoE -/- non-Tg controls. The extent of sudanophilic lesions was reduced within the thoraco-abdominal aorta in ApoE -/- secreted IL-1Ra (-53%) and ApoE -/- intracellular IL-1Ra1 (-67%) Tg mice. In parallel experiments, we observed early mortality and illness among double deficient mice, whereas ApoE -/- IL-1Ra +/+ and ApoE +/+ IL-1Ra -/- mice were apparently healthy. After 7 weeks of diet, ApoE -/- IL-1Ra -/- mice exhibited massive aortic inflammation with destruction of the vascular architecture, but no signs of atherosclerosis. ApoE -/- IL-1Ra +/+ had atherosclerosis and a moderate inflammatory reaction, whereas ApoE +/+ IL-1Ra -/- mice were free of vascular lesions. Macrophages were present in large amounts within inflammatory lesions in the adventitia of ApoE -/- IL-1Ra -/- mice. CONCLUSION: Our results demonstrate that the IL-1/IL-1Ra ratio plays a critical role in the pathogenic mechanisms leading to vascular inflammation and atherosclerosis in ApoE -/- mice.

Animals↗