Role of the eNOS Uncoupling and the Nitric Oxide Metabolic Pathway in the Pathogenesis of Autoimmune Rheumatic Diseases.

Atherosclerosis and its clinical complications constitute the major healthcare problems of the world population. Due to the central role of endothelium throughout the atherosclerotic disease process, endothelial dysfunction is regarded as a common mechanism for various cardiovascular (CV) disorders. It is well established that patients with rheumatic autoimmune diseases are characterized by significantly increased prevalence of cardiovascular morbidity and mortality compared with the general population. The current European guidelines on cardiovascular disease (CVD) prevention in clinical practice recommend to use a 1,5-factor multiplier for CV risk in rheumatoid arthritis as well as in other autoimmune inflammatory diseases. However, mechanisms of accelerated atherosclerosis in these diseases, especially in the absence of traditional risk factors, still remain unclear. Oxidative stress plays the major role in the endothelial dysfunction and recently is strongly attributed to endothelial NO synthase dysfunction (eNOS uncoupling). Converted to a superoxide-producing enzyme, uncoupled eNOS not only leads to reduction of the nitric oxide (NO) generation but also potentiates the preexisting oxidative stress, which contributes significantly to atherogenesis. However, to date, there are no systemic analyses on the role of eNOS uncoupling in the excess CV mortality linked with autoimmune rheumatic diseases. The current review paper addresses this issue.

Liver enzyme abnormalities of inpatients with rheumatic diseases: A 10-year retrospective study in a Korean medicine hospital.

Herbal medicines have been used as a treatment option for rheumatic disease (RD), but they often produce liver enzyme abnormality. This study examines the incidence of herb-induced liver injury (HILI) and the relationship between risk factors and liver enzyme abnormality (LEA) in inpatients with RD. HILI was analyzed using the Roussel Uclaf causality assessment method liver injury criteria and causality assessment. Multivariable analysis was performed to assess the relationship between patient characteristics and LEA in RD. The features of LEA were also examined in each RD. Among 352 patients included in this study, 105 patients showed LEA on admission, of which 6 had fulfilled the Roussel Uclaf causality assessment method criteria. The incidence risks of LEA and HILI were 12.55% and 0.58%, respectively. Multivariable analysis showed that LEA on admission and occasional use of alcohol could be risk factors for LEA on follow-up. In an additional analysis with each RD, all rheumatoid arthritis patients with LEA were taking nonsteroidal anti-inflammatory drugs, steroids, and disease-modifying antirheumatic drugs, and 4 out of 5 gout patients with LEA were taking steroids. The use of herbal medicine in RD is relatively safe. However, regular monitoring of liver enzyme tests and examination of alcohol consumption are required.

Association between TYK2 polymorphisms and susceptibility to autoimmune rheumatic diseases: a meta-analysis.

OBJECTIVE: This study aimed to explore whether TYK2 polymorphisms are associated with susceptibility to autoimmune rheumatic diseases. METHODS: We conducted a meta-analysis on the association between TYK2 polymorphisms and autoimmune rheumatic diseases. RESULTS: Twelve studies with a total of 16,335 patients and 30,065 controls were included in the meta-analysis. Meta-analysis revealed an association between rheumatic diseases and the 2 allele of the TYK2 rs2304256 (OR = 0.885, 95% CI = 0.802-0.978, p = 0.016). Furthermore, stratification by ethnicity identified a significant association between this polymorphism and rheumatic diseases in Caucasians (OR = 0.822, 95% CI = 0.706-0.889, p = 9.5 × 10(-7)), but not in Asians (OR = 1.127, 95% CI = 0.835-1.522, p = 0.434). Meta-analysis by rheumatic disease type revealed a significant association between the 2 allele of the TYK2 rs2304256 and SLE in Caucasians (OR = 0.737, 95% CI = 0.673-0.808, p < 1.0 × 10(-8)) but not in Asians (OR = 1.211, 95% CI = 0.813-1.804, p = 0.347). Meta-analysis revealed that the rs12720356 polymorphism was associated with susceptibility to rheumatic diseases in Caucasians (OR = 0.812, 95% CI = 0.661-0.997, p = 0.046) but not in Asians. Interestingly, the rs280519 polymorphism was significantly associated with susceptibility to SLE both in Caucasians and Asians. However, no associations were found between the rs12720270, rs280500, rs280523 and rs8108236 polymorphisms and susceptibility to rheumatic diseases. CONCLUSIONS: This meta-analysis demonstrates that the TYK2 rs2304256 and rs12720356 polymorphisms are associated with susceptibility to rheumatic diseases, rs2304256 polymorphism is associated with SLE in Caucasians, and rs280519 polymorphism is associated with SLE in Caucasians and Asians.

Activation of mTOR (mechanistic target of rapamycin) in rheumatic diseases.

Mechanistic target of rapamycin (mTOR, also known as mammalian target of rapamycin) is a ubiquitous serine/threonine kinase that regulates cell growth, proliferation and survival. These effects are cell-type-specific, and are elicited in response to stimulation by growth factors, hormones and cytokines, as well as to internal and external metabolic cues. Rapamycin was initially developed as an inhibitor of T-cell proliferation and allograft rejection in the organ transplant setting. Subsequently, its molecular target (mTOR) was identified as a component of two interacting complexes, mTORC1 and mTORC2, that regulate T-cell lineage specification and macrophage differentiation. mTORC1 drives the proinflammatory expansion of T helper (TH) type 1, TH17, and CD4(-)CD8(-) (double-negative, DN) T cells. Both mTORC1 and mTORC2 inhibit the development of CD4(+)CD25(+)FoxP3(+) T regulatory (TREG) cells and, indirectly, mTORC2 favours the expansion of T follicular helper (TFH) cells which, similarly to DN T cells, promote B-cell activation and autoantibody production. In contrast to this proinflammatory effect of mTORC2, mTORC1 favours, to some extent, an anti-inflammatory macrophage polarization that is protective against infections and tissue inflammation. Outside the immune system, mTORC1 controls fibroblast proliferation and chondrocyte survival, with implications for tissue fibrosis and osteoarthritis, respectively. Rapamycin (which primarily inhibits mTORC1), ATP-competitive, dual mTORC1/mTORC2 inhibitors and upstream regulators of the mTOR pathway are being developed to treat autoimmune, hyperproliferative and degenerative diseases. In this regard, mTOR blockade promises to increase life expectancy through treatment and prevention of rheumatic diseases.

[Mycophenolate mofetil--20 years of experience in treatment of rheumatic diseases]. / Mykofenolan mofetylu - 20 lat doswiadczen w leczeniu chorób reumatycznych

Mycophenolate mofetil (MMF) has been used in rheumatology for over 20 years. When transformed to the active metabolite of mycophenolic acid, it is a potent, selective, reversible inhibitor of inosine monophosphate dehydrogenase, a key enzyme of de novo purine synthesis, exerting a cytostatic effect on T and B cells. It also induces apoptosis of antigen-activated T cell clones, reduces the production of antibodies to inhibit the expression of adhesion molecules, reducing the influx of leukocytes and monocytes to inflammatory sites, and has anti-fibrotic properties. Although the main branch of medicine that uses MMF is transplantation, rheumatologists experienced in application of this drug confirmed its usefulness in the treatment of connective tissue diseases. In comparison with immunosuppressives available in rheumatology, MMF has a very good safety profile and is well tolerated by patients. Through multi-center, randomized, controlled clinical trials, MMF has become well established in the treatment of lupus nephritis. Conclusions about its effectiveness in other rheumatologic indications are not entirely clear, being derived from small clinical trials, observational studies and case reports. They suggest that MMF may also be used to treat extrarenal symptoms of SLE, interstitial lung disease in the course of SSc (systemic sclerosis), PM/DM (polymyositis/dermatomyositis), and skin lesions in these diseases, myositis and systemic vasculitis. It should be emphasized that MMF has proved effective in many cases complicated by multidrug resistance to immunosuppressive therapy and has allowed a significant reduction of long-term corticotherapy or its withdrawal.

[Differential diagnosis of elevated liver transaminases in rheumatic diseases]. / Differenzialdiagnose der Transaminasenerhöhung bei rheumatischen Erkrankungen.

During laboratory monitoring of patients with rheumatic diseases it is not uncommon to notice elevated liver transaminase levels. From a rheumatological perspective there are multiple causes for this. Liver dysfunction can be the result of certain rheumatological diseases, such as systemic lupus erythematosus. Primary biliary cirrhosis and primary sclerosing cholangitis are associated with rheumatic diseases. On the other hand, hepatological diseases, such as hepatitis C and autoimmune hepatitis show rheumatological symptoms. The most common cause of elevation of liver transaminase levels in rheumatic patients is without doubt the anti-rheumatic therapy.

Cytochrome P450 interactions and clinical implication in rheumatology.

There are many potential drug interactions that involve the complex cytochromes P450 (CYP) enzyme system when treatments for chronic inflammatory rheumatic diseases are used. This iatrogenic risk is increased in patients taking multiple drugs such as those with rheumatoid arthritis or gout, whatever the type of CYP interaction (substrate, inducer, or inhibitor of one of the CYP isoenzymes). Some of these CYP interactions may have clinical consequences, sometimes serious (overdose or therapeutic failure) and are often unrecognized by clinicians. The aim of this article is first of all to act as a reminder of the metabolic role of membrane-bound CYP enzymes in the liver in the oxidation of drugs and the potential types of interaction (drug substrate, inducer, or inhibitor or indirectly by the modulation of CYP activity through its powerful antiinflammatory activity). Secondly, the different factors that modulate the enzymatic activity of CYP will be described that may contribute to variations in drug metabolism and therefore modify the benefit-risk ratio of the drug. Thirdly, an analysis based on a review of the literature will present the different known interactions via CYP for drugs used in clinical practice in rheumatic diseases: analgesics, antiinflammatory drugs, conventional disease-modifying antirheumatic drugs and biologic agents. To limit the clinical consequences of these CYP interactions, it is recommended to focus on drugs that are really essential, to systematically identify the rheumatic patients most at risk before prescribing, and thus to adopt therapeutic strategies that reduce iatrogenic risk.

[A new therapeutical option for chronic inflammation in rheumatology: janus kinases inhibitors (JAK)]. / Rhumatologie. Une nouvelle option thérapeutique dans la prise en charge de l'inflammation chronique en rhumatologie: les inhibiteurs des janus kinases.

In the last 15 years, the therapeutical options for the treatment of chronic inflammatory diseases in rheumatology have increased a lot. Nevertheless, some patients do not respond or respond partially to the current therapies--including to the biologics therapy. Tofacitinib (Xeljanz) is now on the Swiss market. It inhibits the JAK pathway. Tofacitinib--as monotherapy or with methotrexate--improves the control of rheumatoid arthritis (RA). In a comparative study, tofacitinib was as effective as adalimumab. Further, tofacitinib reduced structural damages in RA and is considered as an alternative, in case of non-response, to anti-TNF and probably to other biologics therapy. The side effects are upper respiratory tract and opportunist infections and tuberculosis. Blood count, lipids, kidney function, liver tests, CK and blood pressure have to be monitored.

Persisting eicosanoid pathways in rheumatic diseases.

An unmet clinical need exists for early treatment of rheumatic diseases and improved treatment strategies that can better maintain remission with reduced ongoing subclinical inflammation and bone destruction. Eicosanoids form one of the most complex networks in the body controlling many physiological and pathophysiological processes, including inflammation, autoimmunity and cancer. Persisting eicosanoid pathways are thought to be involved in the development of rheumatic diseases, and targeting this pathway might enable improved treatment strategies. Several enzymes of the arachidonic acid cascade as well as eicosanoid receptors (all part of the eicosanoid pathway) are today well-recognized targets for anti-inflammatory drugs that can reduce symptoms of inflammation in rheumatic diseases. In this Review, we outline the evidence supporting pivotal roles of eicosanoid signalling in the pathogenesis of rheumatic diseases and discuss findings from studies in animals and humans. We focus first on rheumatoid arthritis and discuss the upregulation of the cyclooxygenase and lipoxygenase pathways as most data are available in this condition. Research into the roles of eicosanoids in other rheumatic diseases (osteoarthritis, idiopathic inflammatory myopathies, systemic lupus erythematosus and gout) is also progressing rapidly and is discussed. Finally, we summarize the prospects of targeting eicosanoid pathways as anti-inflammatory treatment strategies for patients with rheumatic diseases.

The emerging roles of HTRA1 in musculoskeletal disease.

High-temperature requirement serine protease A1 (HTRA1) is one of four known proteases belonging to the broadly conserved family of HTRA proteins. Although it was originally considered as representing an important modulator of tumorigenesis, an increasing number of reports have suggested that its influence on human disease may extend beyond cancer. HTRA1 has the capacity to degrade numerous extracellular matrix proteins, and as such, its potential involvement in diseases of the musculoskeletal system has been gaining increased attention. Musculoskeletal disease constitutes a wide variety of degenerative conditions that can manifest themselves in different ways such as joint and back pain, as well as deficiencies in skeletal bone quality, and ultimately result in significant suffering and reduced quality of life. Convincing data now exist to support a detrimental role for HTRA1 in the pathogenesis of joint and intervertebral disk degeneration. However, the function of HTRA1 in other closely related musculoskeletal diseases affecting bone and muscle remains unclear and largely unexplored. To help set the stage for future research, we discuss here some of the recent advances in our understanding of the role played by HTRA1 in musculoskeletal pathology.

Emerging concepts on inhibitors of indoleamine 2,3-dioxygenase in rheumatic diseases.

The enzyme indoleamine 2,3-dioxygenase 1 (IDO1) finely regulates both innate and adaptive immune responses through the degradation of the essential amino acid tryptophan into kynurenine and other downstream metabolites, which suppress effector T-cell function and promote the differentiation of regulatory T cells. A novel role for IDO1 as a signaling molecule and a modifier of innate inflammatory responses is now emerging. In particular, IDO1 can either support or antagonize inflammation in a context- and tissuedependent manner. Studies in experimental arthritis have unravelled a previously unappreciated role for IDO in controlling B-cell activation and autoantibody production. IDO dysregulation has been documented in patients with systemic lupus erythematosus, systemic sclerosis and Sjogren's syndrome, as well as in severe sepsis and chronic kidney disease. This article summarizes the contribution of IDO to the pathophysiology of inflammatory/autoimmune disorders, and discusses whether strategies to restore metabolic equilibrium in the kynurenine pathway might be pursued in diseases states such as rheumatoid arthritis and systemic sclerosis.

The pleiotropic effects of the hydroxy-methyl-glutaryl-CoA reductase inhibitors in rheumatologic disorders: a comprehensive review.

The hydroxy-methyl-glutaryl-CoA reductase inhibitors (statins) are used extensively in the treatment for hyperlipidemia. They have also demonstrated a benefit in a variety of other disease processes, including a wide range of rheumatologic disorders. These secondary actions are known as pleiotropic effects. Our paper serves as a focused and updated discussion on the pleiotropic effects of statins in rheumatologic disorders and emphasizes the importance of randomized, placebo-controlled trials to further elucidate this interesting phenomenon.

Human anti-alpha-enolase antibody in sera from patients with Behçet's disease and rheumatologic disorders.

OBJECTIVE: alpha-Enolase is a target antigen of IgM-type anti-endothelial cell antibody in patients with Behçet's disease (BD). The objective of this study was to assess the reactivity of serum anti-alpha-enolase antibodies in BD and in other rheumatologic diseases, and to evaluate the clinical significance of serum anti-alpha-enolase antibodies in BD. METHODS: Enzyme-linked immunosorbent assay (ELISA) and immunoblotting were used to examine serum samples from patients with BD (n=100), systemic lupus erythematosus (SLE) (n=50), systemic sclerosis (n=21), rheumatoid arthritis (RA) (n=20), Takayasu's arteritis (n=20), dermatomyositis (n=17), mixed connective tissue disease (MCTD) (n=11), and samples from healthy volunteer donors (n=23). The medical records of patients with BD were reviewed to investigate their clinical characteristics. RESULTS: Specific positive signals against recombinant human alpha-enolase were detected by IgM ELISA of serum samples from 56 of the 100 BD patients (56.0%), 24 of the 50 SLE patients (48.0%), 15 of the 21 systemic sclerosis patients (71.4%), 13 of the 20 RA patients (65.0%), 10 of the 20 Takayasu's arteritis patients (50.0%), 9 of the 17 dermatomyositis patients (52.9%), and 5 of the 11 MCTD patients (45.5%). The number of BD patients with vascular lesions was significantly higher in the anti-alpha-enolase antibody positive group than in the negative group (p=0.027). CONCLUSION: We demonstrated the reactivities of serum anti-alpha-enolase antibodies in BD and other rheumatologic diseases with moderate specificity and also found that serum anti-alpha-enolase antibodies in BD can be associated with vascular system involvement.

Basic science for the clinician 48: tyrosine kinases in disease: the potential for inhibitors in the treatment of immunologic diseases.

The magic bullet--a compound that will stop a disease dead in its tracks by specifically targeting the underlying pathogenic principle of that disease--is what every designer/developer of drugs wants. As cellular and molecular biology research delves deeper into how cells are activated by their ligands, the intracellular pathways of activation of individual cellular processes become better known and more attractive therapeutic targets. The receptors for transforming growth factor beta (TGFbeta) and platelet-derived growth factor (PDGF) activate a variety of cells via a series of tyrosine kinases; inhibition of specific tyrosine kinases has until recently been within the domain of oncologists, treating leukemia, and certain gastrointestinal tumors, but now there is mounting evidence that these agents might be of value in rheumatologic and autoimmune diseases. This is another example of "Better living (and curing!) through chemistry" that we as clinicians need to master to render optimal care.

Protein isoprenylation regulates secretion of matrix metalloproteinase 1 from rheumatoid synovial fibroblasts: effects of statins and farnesyl and geranylgeranyl transferase inhibitors.

OBJECTIVE: To determine whether protein prenylation (farnesyl/geranylgeranylation) regulates matrix metalloproteinase (MMP) secretion from rheumatoid arthritis (RA) synovial fibroblasts (RASFs), and whether MMP-1 secretion can be regulated by statins or prenyltransferase inhibitors via effects mediated by ERK, JNK, and NF-kappaB. METHODS: RASFs obtained from patients during elective knee replacement surgery were assessed by immunoblotting and/or enzyme-linked immunosorbent assay for secretion of MMP-1 and MMP-13 in the presence of tumor necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), statins, the farnesyl transferase (FT) inhibitor FTI-276 and geranylgeranyl transferase inhibitor GGTI-298, and prenyl substrates (farnesyl pyrophosphate [FPP] and geranylgeranyl pyrophosphate [GGPP]). Activities of JNK and ERK were determined by phosphoimmunoblotting, and NF-kappaB activation was determined by nuclear translocation of the p65 component. RESULTS: FTI-276, but not statins, inhibited RASF secretion of MMP-1, but not MMP-13, following induction with TNFalpha (P = 0.0007) or IL-1beta (P = 0.006). Loading RASFs with FPP to promote farnesylation enhanced MMP-1 secretion. FTI-276 inhibited activation of JNK (P < 0.05) and NF-kappaB (P = 0.02), but not ERK. In contrast, GGTI-298 enhanced, while GGPP inhibited, MMP-1 secretion. FTI-276 and GGTI-298 together had no effect on MMP-1 secretion. Stimulation of RASFs with TNFalpha or IL-1beta led to increased expression and activity of FT. CONCLUSION: Protein farnesylation is required for expression and secretion of MMP-1 from RASFs, via effects on JNK and NF-kappaB. The ability of cytokines to stimulate the expression and activity of FT suggests that FT may be increased in the rheumatoid joint. In contrast, geranylgeranylation down-regulates MMP-1 expression. Statins simultaneously inhibit farnesylation and geranylgeranylation, and in consequence do not inhibit MMP-1 secretion. The ability of FTI-276 to inhibit MMP-1 secretion suggests a potential therapeutic strategy in RA.

Efficacy of the newest COX-2 selective inhibitors in rheumatic disease.

Non-steroidal antiinflammatory drugs (NSAIDs) are standard treatment for the pain and inflammation associated with arthritis. Traditional NSAIDs and cyclooxygenase-2 (COX-2) selective inhibitors exhibit comparable efficacy, with different safety profiles. Traditional NSAIDs are associated with an increased risk of serious gastrointestinal (GI) adverse events versus COX-2 selective inhibitors, and chronic use frequently necessitates adjunctive therapy with gastroprotective agents. COX-2 selective inhibitors are often used in preference to avoid these GI adverse events. Recent studies have raised the concern that COX-2 selective inhibitors and traditional NSAIDs appear to be associated with a higher incidence of thrombotic cardiovascular events versus placebo. The key in prescribing these agents is for the physician to take a proactive approach to patient management and evaluation of GI and cardiovascular risk factors. This review examines the role of the newest COX-2 selective inhibitors, etoricoxib and lumiracoxib, in treating rheumatic disease.

Reactive oxygen species and superoxide dismutases: role in joint diseases.

Reactive oxygen species (ROS) are produced in many normal and abnormal processes in humans, including atheroma, asthma, joint diseases, aging, and cancer. The superoxide anion O(2)(-) is the main ROS. Increased ROS production leads to tissue damage associated with inflammation. Superoxide dismutases (SODs) convert superoxide to hydrogen peroxide, which is then removed by glutathione peroxidase or catalase. Thus, SODs prevent the formation of highly aggressive ROS, such as peroxynitrite or the hydroxyl radical. Experimental models involving SOD knockout or overexpression are beginning to shed light on the pathophysiological role of SOD in humans. Although the antiinflammatory effects of exogenous native SOD (orgotein) are modest, synthetic SOD mimetics hold considerable promise for modulating the inflammatory response. In this review, we discuss new knowledge about the role of the superoxide anion and its derivates as mediators of inflammation and the role of SODs and SOD mimetics as antioxidant treatments in joint diseases such as rheumatoid arthritis, osteoarthritis, and crystal-induced arthropathies.

[The profile and clinical significance of azathioprine metabolic enzymes activity in rheumatological patients].

OBJECTIVE: To detect the activity of thiopurine methyltransferase (TPMT) and its relationship with azathioprine (AZA) tolerance. METHODS: 200 patients of rheumatism need AZA were included in the study. RBC TPMT activity was detected with high performance liquid chromatography. Then the patients took AZA doses of 50 mg/d for the first month, 100 mg/d for the second month and 150 mg/d for the third month. RESULTS: TPMT activity of 200 patients ranged from 0.75 - 32.35 U/ml RBC, averaged (12.04 +/- 6.90) U/ml RBC. The activity of TPMT showed a normal skewness distribution and no activity deficiency was founded. 194 patients (97%) completed the 3 month follow-up. 18 showed bone marrow depression including 2 severe hematological crisis and 6 showed hepatic damage during the 3 months. Bone marrow depression was recorded of 7 cases with the TPMT activity of 2.24 - 5.97 U/ml RBC, averaged (3.47 +/- 1.21) U/ml RBC, among the dose of 50 mg/d and 11 cases with the TPMT activity of 4.01 - 11.17 U/ml RBC, averaged (7.08 +/- 2.58) U/ml RBC, among the dose of 100 - 150 mg/d. The other 176 cases did not show bone marrow depression at all, with TPMT activity of 4.47 - 32.35 U/ml RBC, averaged (13.02 +/- 6.07) U/ml RBC. TPMT activities in the 3 groups of patients were significantly different according to statistical analysis (P < 0.01). CONCLUSIONS: Hematological side effects were highly associated with TPMT activity in AZA usage. Patients with low TPMT activity should use low dose of AZA routinely, even though, toxicity may occur. Test of TPMT activity before AZA description was of significance.