Advances in the treatment of rheumatoid arthritis: old versus new therapies

α-Mangostin Inhibited M1 Polarization of Macrophages/Monocytes in Antigen-Induced Arthritis Mice by Up-Regulating Silent Information Regulator 1 and Peroxisome Proliferators-Activated Receptor γ Simultaneously

Background

α-Mangostin (MG) showed the potentials in alleviating experimental arthritis, inhibiting inflammatory polarization of macrophages/monocytes, and regulating peroxisome proliferators-activated receptor γ (PPAR-γ) and silent information regulator 1 (SIRT1) signals. The aim of this study was to analyze the correlations among the above-mentioned properties.

Methods

Antigen-induced arthritis (AIA) was established in mouse, which was treated with MG in combination with SIRT1/PPAR-γ inhibitors to clarify the role of the two signals in the anti-arthritic actions. Pathological changes were systematically investigated. Phenotypes of cells were investigated by flow cytometry. Expression and co-localization of SIRT1 and PPAR-γ proteins in joint tissues were observed by the immunofluorescence method. Finally, clinical implications from the synchronous up-regulation of SIRT1 and PPAR-γ were validated by experiments in vitro.

Results

SIRT1 and PPAR-γ inhibitors (nicotinamide and T0070097) reduced the therapeutic effects of MG on AIA mice, and abrogated MG-induced up-regulation of SIRT1/PPAR-γ and inhibition of M1 polarization in macrophages/monocytes. MG has a good binding affinity to PPAR-γ, and MG promoted the co-expression of SIRT1 and PPAR-γ in joints. Synchronously activating SIRT1 and PPAR-γ was revealed to be necessary by MG to repress inflammatory responses in THP-1 monocytes.

Conclusion

MG binds PPAR-γ and excites this signaling to initiate ligand-dependent anti-inflammatory activity. Due to certain unspecified signal transduction crosstalk mechanism, it then promoted SIRT1 expression and further limited inflammatory polarization of macrophages/monocytes in AIA mice.

Xanthones from securidaca inappendiculata antagonizes the anti-rheumatic effect of methotrexate by inhibiting reduced folate carrier 1

BACKGROUND

The first-line anti-rheumatic drug methotrexate (MTX) is used in the combination. Because of the unpredictable adverse reactions, optimization of relevant regimens is necessary and meaningful. This study aimed to study the possible interaction between Securidaca inappendiculate Hassk. Derived xanthones and MTX.

METHODS

We established adjuvant-induced arthritis (AIA) model, which was treated with MTX and MTX + xanthone-rich fraction (XRF). The clinical efficacy was evaluated by histopathological examination, and LC-MS was used to monitor the blood concentration of MTX. Western blotting and immunohistochemistry were used to detect protein expression. In vitro, we assessed the activity of related transporters by cellular uptake assay based on HEK-293T cells.

RESULTS

Compared with MTX-treated rats, inflammation in the immunized rats in the MTX + XRF group was obvious, indicating that XRF antagonized the anti-rheumatic effect of MTX. Meanwhile, XRF reduced liver and kidney injuries caused by MTX in addition to MTX. Results from immunohistochemical and nappendiculat assays suggested that XRF may reduce uptake of MTX by down-regulating reduced folate carrier 1 (RFC1).

CONCLUSION

This study indicated that XRF could reduce the plasma concentration of MTX by inhibiting the expression of RFC1, antagonize the therapeutic effect of MTX on AIA rats, and reduce its oral bioavailability. The combination of S. inappendiculate and MTX should be further optimized to achieve the goal of increasing efficiency and reducing toxicity.

An open-label, prospective, single-arm study of switching from infliximab to cyclosporine for refractory uveitis in patients with Behçet's disease in long-term remission

PURPOSE

Although infliximab (IFX) decreases the risk of blindness due to refractory uveitis in patients with Behçet's disease (BD), there are no standard criteria for IFX switching or withdrawal. To evaluate the effect of IFX switching in patients with BD in long-term remission, a prospective, single-arm intervention trial was conducted, switching from IFX to cyclosporine A (CYA).

STUDY DESIGN

A prospective open-label study.

METHODS

Eligible patients met the following criteria: administration of IFX without concomitant immunosuppressants for more than 5 years with no episodes of ocular attacks, no retinal vasculitis on fluorescein fundus angiography, negative C-reactive protein in serum, and no extraocular lesions at the time of IFX withdrawal. CYA 5 mg/kg/day was administered from 6 weeks after IFX withdrawal. The primary outcome was the rate of readministration of tumor necrosis factor inhibitors at 1 year after IFX withdrawal.

RESULTS

Three of 45 BD patients treated with IFX for refractory uveitis were included in the study. At 1 year after withdrawal of IFX, no patient had experienced any ocular attacks or needed readministation of IFX. However, extraocular lesions, such as recurrent oral ulcers, folliculitis, and recurrent fevers, occurred in all patients. Liver or renal dysfunction, which may have been caused by CYA, was also observed in all patients.

CONCLUSIONS

Although no ocular attacks were observed for at least 1 year after IFX withdrawal, this prospective study indicates that IFX withdrawal should be considered carefully, even for patients in long term remission of ocular and extraocular lesions.

Anti-nociceptive effect of Portulaca oleracea L. ethanol extracts attenuated zymosan-induced mouse joint inflammation via inhibition of Nrf2 expression

The aim of this study was to explore the effects of ethanol extracts from Portulaca oleracea L. (ePO) on joint inflammation and to explain the underlying mechanisms. A joint inflammation mouse model was constructed by injecting zymosan, and the Von Frey method was employed and the joint thickness measured. The numbers of leukocytes, neutrophils, and monocytes were counted in the joint cavity and the infiltration of inflammatory cells was assessed by joint histopathological analysis. The mRNA levels of inflammatory cytokines were determined by quantitative RT-PCR and their secretion levels were determined by specific ELISAs. Pre-treatment with ePO inhibited articular mechanical hyperalgesia and edema and ameliorated the recruitment of mononuclear neutrophils and leukocytes. In addition, pre-treatment with ePO improved pathological alternations in the joint tissues by reducing the number of inflammatory cells. Pre-treatment with ePO regulated the nuclear factor erythroid 2-related factor 2 (Nrf2)-related proteins and thereby inhibited oxidative stress. In addition, ePO inhibited NLR family pyrin domain containing 3 (NLRP3) inflammasome-related genes (NLRP3, ASC, pro-caspase-1 and pro-IL-1ß), modulated inflammatory cytokines and the activation of NF-κB. ePO attenuated zymosan-induced joint inflammation by regulating oxidative stress, NLRP3 inflammasome, and NF-κB.

Potential repurposed SARS-CoV-2 (COVID-19) infection drugs

The global outbreak of COVID-19 viral infection is associated with the absence of specific drug(s) for fighting this viral infection. About 10 million people are already infected, about 500 000 deaths all over the world to date. Great efforts have been made to find solutions for this viral infection, either vaccines, monoclonal antibodies, or small molecule drugs; this can stop the spread of infection to avoid the expected human, economic and social catastrophe associated with this infection. In the literature and during clinical trials in hospitals, several FDA approved drugs for different diseases have the potential to treat or reduce the severity of COVID-19. Repurposing of these drugs as potential agents to treat COVID-19 reduces the time and cost to find effective COVID-19 agents. This review article summarizes the present situation of transmission, pathogenesis and statistics of COVID-19 in the world. Moreover, it includes chemistry, mechanism of action at the molecular level of the possible drug molecules which are liable for redirection as potential COVID-19 therapeutic agents. This includes polymerase inhibitors, protease inhibitors, malaria drugs, lipid lowering statins, rheumatoid arthritis drugs and some miscellaneous agents. We offer research data and knowledge about the chemistry and biology of potential COVID-19 drugs for the research community in this field.

Low Dietary c9t11-Conjugated Linoleic Acid Intake from Dairy Fat or Supplements Reduces Inflammation in Collagen-Induced Arthritis

Dietary cis-9,trans-11 (c9t11) conjugated linoleic acid (CLA) fed at 0.5 % w/w was previously shown to attenuate inflammation in the murine collagen-induced (CA) arthritis model, and growing evidence implicates c9t11-CLA as a major anti-inflammatory component of dairy fat. To understand c9t11-CLA's contribution to dairy fat's anti-inflammatory action, the minimum amount of dietary c9t11-CLA needed to reduce inflammation must be determined. This study had two objectives: (1) determine the minimum dietary anti-inflammatory c9t11-CLA intake level in the CA model, and (2) compare this to anti-inflammatory effects of dairy fat (non-enriched, naturally c9t11-CLA-enriched, or c9t11-CLA-supplemented). Mice received the following dietary fat treatments (w/w) post arthritis onset: corn oil (6 % CO), 0.125, 0.25, 0.375, and 0.5 % c9t11-CLA, control butter (6 % CB), c9t11-enriched butter (6 % EB), or c9t11-CLA-supplemented butter (6 % SB, containing 0.2 % c9t11-CLA). Paw arthritic severity and pad swelling were scored and measured, respectively, over an 84-day study period. All c9t11-CLA and butter diets decreased the arthritic score (25-51 %, P < 0.01) and paw swelling (8-11 %, P < 0.01). Throughout the study, plasma tumor necrosis factor (TNFα) was elevated in CO-fed arthritic mice compared to non-arthritic (NA) mice but was reduced in 0.5 % c9t11-CLA- and EB-fed mice. Interleukin-1β and IL-6 were increased in arthritic CO-fed mice compared to NA mice but were reduced in 0.5 % c9t11-CLA- and EB-fed mice through day 42. In conclusion, 0.125 % c9t11-CLA reduced clinical arthritis as effectively as higher doses, and decreased arthritis in CB-fed mice suggested that the minimal anti-inflammatory levels of c9t11-CLA might be below 0.125 %.

Ocular Behçet disease: current therapeutic approaches

PURPOSE OF REVIEW

To alert physician to timely recognition and current treatment of recurrent hypopyon iridocyclitis or panuveitis in ocular Behçet disease (OBD).

RECENT FINDINGS

Interferon-α, rituximab, intravitreal triamcinolone, and biological response modifiers by tumor necrosis factor inhibitors such as infliximab and adalimumab are being used increasingly for the treatment of severe sight-threatening ocular inflammation including retinal vasculitis and cystoid macular edema (CME).

SUMMARY

Biological agents offer tremendous potential in the treatment of OBD. Given that OBD predominantly afflicts the younger adults in their most productive years, dermatologist, rheumatologist, internist, or general practitioners supervising patients with oculo-articulo-oromucocutaneous syndromes should be aware of systemic Behçet disease. Early recognition of ocular involvement is important and such patients should strongly be instructed to visit immediately an ophthalmologist, as uveitis management differs from extraocular involvements with high ocular morbidity from sight-threatening complications due to relapsing inflammatory attacks in the posterior segment of the eye. A single infliximab infusion should be considered for the control of acute panuveitis, whereas repeated long-term infliximab infusions were proved to be more effective in reducing the number of episodes in refractory uveoretinitis with faster regression and complete remission of CME.

T-cell and natural killer-cell large granular lymphocyte leukemia neoplasias

Large granular lymphocyte (LGL) leukemia is a rare disorder of cytotoxic lymphocytes. LGL cells play an integral role in the immune system and are divided into two major lineages of CD3(-)natural killer (NK) cells and CD3(+) T cells that circulate throughout the blood in search of infected cells, in which they will make contact through a receptor ligand and induce cell death. LGL cells are also programmed to undergo apoptosis after contact with an infected target cell; however, they continue to survive in individuals with LGL leukemia. This unchecked proliferation and cytotoxicity of LGLs in patients results in autoimmunity or malignancy. Rheumatoid arthritis is the most common autoimmune condition seen in individuals with LGL leukemia; however, LGL leukemia is associated with a wide spectrum of other autoimmune diseases. Patients may also suffer from other hematological conditions including hemolytic anemia, pure red cell aplasia, and neutropenia, which lead to recurrent bacterial infections. Currently, the only established treatment involves a low dose of an immunosuppressive regimen with methotrexate, in which 40-50% of patients are either resistant or do not respond. In order to establish new therapeutics it is important to understand the current state of LGL leukemia both in the clinic and in basic research.

Genetic evidence for involvement of neuronally expressed S1P₁ receptor in nociceptor sensitization and inflammatory pain

Sphingosine-1-phosphate (S1P) is a key regulator of immune response. Immune cells, epithelia and blood cells generate high levels of S1P in inflamed tissue. However, it is not known if S1P acts on the endings of nociceptive neurons, thereby contributing to the generation of inflammatory pain. We found that the S1P₁ receptor for S1P is expressed in subpopulations of sensory neurons including nociceptors. Both S1P and agonists at the S1P₁ receptor induced hypersensitivity to noxious thermal stimulation in vitro and in vivo. S1P-induced hypersensitivity was strongly attenuated in mice lacking TRPV1 channels. S1P and inflammation-induced hypersensitivity was significantly reduced in mice with a conditional nociceptor-specific deletion of the S1P₁ receptor. Our data show that neuronally expressed S1P₁ receptors play a significant role in regulating nociceptor function and that S1P/S1P₁ signaling may be a key player in the onset of thermal hypersensitivity and hyperalgesia associated with inflammation.

Monocyte scintigraphy in rheumatoid arthritis: the dynamics of monocyte migration in immune-mediated inflammatory disease

BACKGROUND

Macrophages are principal drivers of synovial inflammation in rheumatoid arthritis (RA), a prototype immune-mediated inflammatory disease. Conceivably, synovial macrophages are continuously replaced by circulating monocytes in RA. Animal studies from the 1960s suggested that macrophage replacement by monocytes is a slow process in chronic inflammatory lesions. Translation of these data into the human condition has been hampered by the lack of available techniques to analyze monocyte migration in man.

METHODS/PRINCIPAL FINDINGS

We developed a technique that enabled us to analyze the migration of labelled autologous monocytes in RA patients using single photon emission computer tomography (SPECT). We isolated CD14+ monocytes by CliniMACS in 8 patients and labeled these with technetium-99m (99mTc-HMPAO). Monocytes were re-infused into the same patient. Using SPECT we calculated that a very small but specific fraction of 3.4 x 10(-3) (0.95-5.1 x 10(-3)) % of re-infused monocytes migrated to the inflamed joints, being detectable within one hour after re-infusion.

CONCLUSIONS/SIGNIFICANCE

The results indicate monocytes migrate continuously into the inflamed synovial tissue of RA patients, but at a slow macrophage-replacement rate. This suggests that the rapid decrease in synovial macrophages that occurs after antirheumatic treatment might rather be explained by an alteration in macrophage retention than in monocyte influx and that RA might be particularly sensitive to treatments targeting inflammatory cell retention.

Approaches to the treatment of early rheumatoid arthritis with disease-modifying antirheumatic drugs

This paper reviews recent approaches to treatment of early rheumatoid arthritis (RA) with disease-modifying antirheumatic drugs (DMARDs). The literature on treatment the early RA published between 1995 and 2007 was accessed through the PubMed database from the National Library of Medicine. Keywords were 'early rheumatoid arthritis', 'disease-modifying antirheumatic drugs', 'biologic agents' and 'combination therapy'. Only results of trials on human subjects that directly measured the effects of DMARDs or biological agents on clinical, laboratory parameters and radiological progression of early RA were selected. Combination therapy suppresses RA activity and radiological progression more effectively than monotherapy. If better control of RA is evident after 3-6 months of treatment with the combination of DMARDs, one must still decide whether to stop the first DMARD, stop the second, or continue with the combination. Combination therapy biological agents (infliximab, adalimumab) with methotrexate and etanercept therapy alone may induce remission in many patients with early RA. It is a method of choice in patients with an adverse prognosis. The main indications for combination therapy 'standard' DMARDs or combination 1 DMARDs with a biological agent are such variables as detection of a shared epitope, increase of concentration of anticyclic citrullinated peptide antibodies, rheumatoid factor, C-reactive protein, 28-joint disease activity score, Sharp score and presence of erosion in joints. The majority of rheumatologists believe that patients with RA should be treated with DMARDs earlier rather than later in the disease process. Further trials should establish the optimal approaches to early RA therapy.

Immunosuppressants in advanced clinical development for organ transplantation and selected autoimmune diseases

Immunosuppressants dampen the immune response or restore balance among immune system components. They are primarily used to prevent allograft rejection after organ transplantation and to prevent or treat disease flares in autoimmune diseases. Immunosuppressants available at present include the calcineurin inhibitors (cyclosporin, tacrolimus), antimetabolites (azathioprine, leflunomide, methotrexate, mycophenolate mofetil), antiproliferatives (sirolimus), monoclonal antibodies to T lymphocyte (basiliximab, daclizumab, muromonab-CD3) and anticytokines (anakinra, etanercept, infliximab). The immunosuppressive market grows at a rate of > 10% yearly, with total sales in 2001 of US$2.7 billion. Immunotherapy in transplantation and autoimmune diseases is tending towards the use of multi-drug regimens tailored for the individual patient. At least 23 new immunosuppressants are currently in advanced clinical testing or preregistration, and can be divided into three groups. First, emerging drugs targeting intracellular ligands in immune cells are primarily analogues of currently-marketed agents, which attempt to provide improved pharmaceutical or safety profiles compared with the prototype compound. They are largely being developed in organ transplantation. Second, emerging drugs targeting cell surface ligands on immune cells attempt to antagonise novel molecular sites to interfere with immune cell activation via costimulatory signals, immune cell adhesion to tissues or the vasculature and immune cell trafficking. These agents are being primarily developed in rheumatoid arthritis, psoriasis and/or multiple sclerosis. Finally, emerging drugs acting as anticytokines, which largely follow on from the success of those on the market, by antagonising the function of tumour necrosis factor or a narrow selection of interleukins. All are being assessed in rheumatoid arthritis. Drug development of immunosuppressants is increasingly attempting to intervene in disease progression over the long term. These efforts bring with them trial design and regulatory issues, such as what markers can be used as trial outcome measures, over what duration do trials need to be conducted and what labelling claims are allowed. With the intensive activity in this field, it is likely that several new drugs will reach the market in the coming decade. One caveat, however, is that emerging immunosuppressants that are likely to capture a reasonable share of this increasingly-fragmented market must demonstrate the ability to achieve disease remission or long-term slowing of disease progression.

Attenuation of murine collagen-induced arthritis by a novel, potent, selective small molecule inhibitor of IkappaB Kinase 2, TPCA-1 (2-[(aminocarbonyl)amino]-5-(4-fluorophenyl)-3-thiophenecarboxamide), occurs via reduction of proinflammatory cytokines and antigen-induced T cell Proliferation

Demonstration that IkappaB kinase 2 (IKK-2) plays a pivotal role in the nuclear factor-kappaB-regulated production of proinflammatory molecules by stimuli such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 suggests that inhibition of IKK-2 may be beneficial in the treatment of rheumatoid arthritis. In the present study, we demonstrate that a novel, potent (IC(50) = 17.9 nM), and selective inhibitor of human IKK-2, 2-[(aminocarbonyl)amino]-5-(4-fluorophenyl)-3-thiophenecarboxamide (TPCA-1), inhibits lipopolysaccharide-induced human monocyte production of TNF-alpha, IL-6, and IL-8 with an IC(50) = 170 to 320 nM. Prophylactic administration of TPCA-1 at 3, 10, or 20 mg/kg, i.p., b.i.d., resulted in a dose-dependent reduction in the severity of murine collagen-induced arthritis (CIA). The significantly reduced disease severity and delay of disease onset resulting from administration of TPCA-1 at 10 mg/kg, i.p., b.i.d. were comparable to the effects of the antirheumatic drug, etanercept, when administered prophylactically at 4 mg/kg, i.p., every other day. Nuclear localization of p65, as well as levels of IL-1beta, IL-6, TNF-alpha, and interferon-gamma, were significantly reduced in the paw tissue of TPCA-1- and etanercept-treated mice. In addition, administration of TPCA-1 in vivo resulted in significantly decreased collagen-induced T cell proliferation ex vivo. Therapeutic administration of TPCA-1 at 20 mg/kg, but not at 3 or 10 mg/kg, i.p., b.i.d., significantly reduced the severity of CIA, as did etanercept administration at 12.5 mg/kg, i.p., every other day. These results suggest that reduction of proinflammatory mediators and inhibition of antigen-induced T cell proliferation are mechanisms underlying the attenuation of CIA by the IKK-2 inhibitor, TPCA-1.