Interleukin-35 (IL-35) inhibits proliferation and promotes apoptosis of fibroblast-like synoviocytes isolated from mice with collagen-induced arthritis

Rheumatoid arthritis (RA) is an inflammatory disorder of the joints that affects 0.5–1 % of adults. Excessive growth of the fibroblast-like synoviocytes (FLS) promotes hyperplasia of synovial tissues and causes its invasion into the bone and cartilage, which eventually causes deformity and dysfunction of affected joints. Interleukin 35 (IL-35) was shown to suppress the inflammatory responses to collagen-induced arthritis (CIA) via upregulation of T regulatory cells and suppression of T helper type 17 cells in a mouse model. To study the effects of IL-35 on the proliferation and apoptosis frequency of cultured FLS isolated from mice with CIA as well as to examine the effects of IL-35 on CIA in vivo. Thirty DBA/1 J mice, which are used as an animal model for RA, were divided randomly (ten mice per group) to a CIA group (collagen treatment), a CIA + IL-35 group (collagen and IL-35 treatments), and a control group (no treatment). Starting on the 24th day after collagen administration, IL-35 was injected intraperitoneally into mice of the CIA + IL-35 group once per day for 10 days. An arthritis index was calculated, and pathological analysis of synovial tissue was performed. FLS isolated from CIA mice were treated with various concentrations of IL-35 (12.5–100 ng/ml). The MTT assay was used to examine FLS proliferation, and apoptosis frequency of FLS was detected by flow cytometry. On day 24, the CIA mice began to exhibit arthritis symptoms, and the symptoms rapidly progressed with time. Treatment with IL-35 significantly alleviated arthritis symptoms and reduced the synovial tissue inflammation. In addition, IL-35 treatment inhibited proliferation and promoted apoptosis in cultured FLS from CIA mice in a dose-dependent manner. IL-35 could ameliorate the symptoms of arthritis in the CIA mouse model in vivo and inhibited FLS proliferation while promoting FLS apoptosis in vitro, thereby exhibited the potential in inhibiting the progression of RA.     

Betulinic acid inhibits cell proliferation,migration, and inflammatory response in rheumatoid arthritis fibroblast-like synoviocytes

Betulinic acid (BA), a pentacyclic triterpene derived from the bark of the white birch tree, has been reported to have a variety of pharmacological effects, including antioxidant, anti-inflammatory, antitumor, immunomodulatory, and antiarthritis properties. However, the role of BA in rheumatoid arthritis (RA) remains unclear. Thus, the objective of this study was to examine the effects of BA on RA fibroblast-like synoviocytes (RA-FLS) proliferation, migration, and inflammatory response, and further explore the potential underlying mechanisms. Our results showed that BA inhibited the proliferation, migration, and invasion of RA-FLSs. BA also attenuated tumor necrosis factor-α (TNF-α), enhanced matrix metalloproteinases (MMPs) expression, and inflammatory cytokines production in RA-FLS. Furthermore, BA prevented the activation of Akt/NF-κB pathway in RA-FLS exposed to TNF-α. In conclusion, these findings indicated that BA inhibits cell proliferation, migration, and inflammatory response in RA-FLS; and the Akt/NF-κB signaling pathway was involved in the protective effect of BA on RA-FLS. Thus, BA might be a potential therapeutic agent for the treatment of RA.     

Chemerin activates fibroblast-like synoviocytes in patients with rheumatoid arthritis

Introduction

Chemerin is a chemotactic agonist identified as a ligand for ChemR23 that is expressed on macrophages and dendritic cells (DCs). In this study, we analyzed the expression of chemerin and ChemR23 in the synovium of rheumatoid arthritis (RA) patients and the stimulatory effects of chemerin on fibroblast-like synoviocytes (FLSs) from RA patients.

Methods

Chemerin and ChemR23 expression in the RA synovium was ascertained by immunohistochemistry and Western blot analysis. Chemerin expression on cultured FLSs was analyzed by ELISA. ChemR23 expression on FLSs was determined by immunocytochemistry and Western blot analysis. Cytokine production from FLSs was measured by ELISA. FLS cell motility was evaluated by utilizing a scrape motility assay. We also examined the stimulating effect of chemerin on the phosphorylation of mitogen-activated protein kinase (MAPK), p44/42 mitogen-activated protein kinase (ERK1/2), p38MAPK, c-Jun N-terminal kinase (JNK)1/2 and Akt, as well as on the degradation of regulator of NF-κB (IκBα) in FLSs, by Western blot analysis.

Results

Chemerin was expressed on endothelial cells and synovial lining and sublining cells. ChemR23 was expressed on macrophages, immature DCs and FLSs and a few mature DCs in the RA synovium. Chemerin and ChemR23 were highly expressed in the RA synovium compared with osteoarthritis. Chemerin and ChemR23 were expressed on unstimulated FLSs. TNF-α and IFN-γ upregulated chemerin production. Chemerin enhanced the production of IL-6, chemokine (C-C motif) ligand 2 and matrix metalloproteinase 3 by FLSs, as well as increasing FLS motility. The stimulatory effects of chemerin on FLSs were mediated by activation of ERK1/2, p38MAPK and Akt, but not by JNK1/2. Degradation of IκB in FLSs was not promoted by chemerin stimulation. Inhibition of the ERK1/2, p38MAPK and Akt signaling pathways significantly suppressed chemerin-induced IL-6 production. Moreover, blockade of the p38MAPK and Akt pathways, but not the ERK1/2 pathway, inhibited chemerin-enhanced cell motility.

Conclusions

The interaction of chemerin and ChemR23 may play an important role in the pathogenesis of RA through the activation of FLSs.     

Madecassoside attenuates inflammatory response on collagen-induced arthritis in DBA/1 mice

Madecassoside (MA), a triterpenoid product isolated from Centella asiatica, has been described to exhibit antioxidant and anti-inflammatory activities. The present study was undertaken to determine whether madecassoside (MA) is efficacious against collagen-induced arthritis (CIA) in mice and its possible mechanisms. DBA/1J mice were immunized with bovine type II collagen and treated with MA (3, 10 and 30 mg/kg d, i.g.) from days 21 to 42 after immunization. Arthritis was evaluated by hind paw swelling, polyarthritis index, and histological examination. In vitro proliferation of spleen cells was examined using 3-[4,5-dimethylthylthiazol-2-yl]-2, 5-diphenyltetrazoliumbromide (MTT) assay. Plasma levels of cytokines tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10) and the expression of prostaglandin E₂ (PGE₂), cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in synovial tissues were also determined. The results showed that comparing with untreated CIA mice, treated with MA dose-dependently suppressed the clinical arthritis score and joints tissues pathological damage, reduced the proliferation of spleen cells, plasma levels of TNF-α and IL-6, synovial tissues PGE₂ production and COX-2 protein expression, however, the expression of COX-1 in symovial tissues did not change and the plasma levels of IL-10 were increased. These results suggest that MA can effectively alleviate inflammatory response on CIA, and anti-inflammatory effects of MA can be attributed, at least partially, to the inhibition of pro-inflammatory mediators, including COX-2 expression, PGE₂ production, TNF-α and IL-6 levels and the up-regulation anti-inflammatory molecule IL-10.     

Syndecan-4 involves in the pathogenesis of rheumatoid arthritis by regulating the inflammatory response and apoptosis of fibroblast-like synoviocytes

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease, and the pathogenesis of RA is still unknown. Rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs) are of significance in the pathogenesis of RA. In this study, three microarray profiles (GSE55457, GSE55584, and GSE55235) of human joint FLSs from 33 RA patients and 20 normal controls were extracted from the Gene Expression Omnibus Dataset and analyzed to investigate the underlying pathogenesis of RA. As analyzed by the differently expressed genes, gene ontology, Kyoto Encyclopedia of Genes and Genomes pathway enrichment, and protein-protein interaction network analysis, syndecan-4 (SDC4), a receptor of multiple cytokines and chemokines, which played a key role in the regulation of inflammatory response, was found to be an essential regulator in RA. To further validate these results, the levels of SDC4, reactive oxygen species (ROS), nitric oxide (NO), inflammation, and apoptosis in RA-FLSs were examined. SDC4-silenced RA-FLSs were also used. The results demonstrated that SDC4 and the level of ROS, NO, and inflammation were highly expressed while the apoptosis was decreased in RA-FLSs compared with normal FLSs. SDC4 silencing significantly suppressed the levels of ROS, NO, and inflammation; elevated the expression of nuclear factor erythroid 2-related factor 2; and promoted the apoptosis of RA-FLSs. Collectively, our results demonstrated a new mechanism of SDC4 in initiating the inflammation and inhibiting the apoptosis of RA-FLSs and that a potential target for the diagnosis and treatment of RA in the clinic might be developed.     

Andrographolide induces cell cycle arrest and apoptosis in human rheumatoid arthritis fibroblast-like synoviocytes

The pseudo-tumoral expansion of fibroblast-like synoviocytes is a hallmark of rheumatoid arthritis (RA), and targeting rheumatoid arthritis fibroblast-like synoviocytes (RAFLSs) may have therapeutic potentials in this disease. Andrographolide, a diterpenoid compound isolated from the herb Andrographis paniculata, has been reported to have potent anti-inflammatory activity. In the present study, we aimed to investigate the effects of andrographolide on human RAFLSs and the underlying molecular mechanism(s). RAFLSs were isolated from patients with RA and treated with or without various concentrations (i.e., 10, 20, and 30 μM) of andrographolide for 48 h. 3-[4,5-Dimethyl-2-yl]-2,5-diphenyl tetrazolium bromide assay revealed that andrographolide treatment decreased the proliferation of RAFLSs in a dose-dependent manner. Cell cycle analysis using propidium iodide (PI) staining showed a G0/G1 cell cycle arrest in andrographolide-treated RAFLSs. Immunoblotting analysis of key cell cycle regulators demonstrated that andrographolide treatment caused a dose-dependent increase in the expression of cell-cycle inhibitors p21 and p27 and a concomitant reduction of cyclin-dependent kinase 4. Exposure to andrographolide-induced apoptosis of RAFLSs measured by annexin V/PI double staining, which was coupled with promotion of cytochrome C release from mitochondria and activation of caspase-3. Moreover, andrographolide-treated RAFLSs displayed a significant decrease in the Bcl-2/Bax ratio compared to untreated cells. In conclusion, our data demonstrate that andrographolide exerts anti-growth and pro-apoptotic effects on RAFLSs, thus may have therapeutic potential for the treatment of RA.     

Effects of inflammatory cytokine IL-27 on the activation of fibroblast-like synoviocytes in rheumatoid arthritis

Introduction  

Interleukin (IL)-27 is a novel member of the IL-6/IL-12 family cytokines that are produced early by antigen-presenting cells in T helper (Th)1-mediated inflammation. Elevated expression of IL-27 has been detected in the synovial membranes and fluid of rheumatoid arthritis (RA).     

Dexamethasone inhibits BAFF expression in fibroblast-like synoviocytes from patients with rheumatoid arthritis

Fibroblast-like synoviocytes (FLS) play a major role in the pathogenesis of rheumatoid arthritis (RA). FLS isolated from patients with RA (FLS-RA) express B cell-activating factor belonging to the TNF family (BAFF), a cytokine that has been associated with the onset and progression of RA. Glucocorticoids are powerful anti-inflammatory drugs used in the treatment of RA. In the present study, we examined the effect of dexamethasone (Dex) on constitutive and TNF-alpha- and IFN-gamma-induced BAFF expression in FLS-RA. BAFF mRNA expression and soluble BAFF were determined by RT-PCR and ELISA, respectively. The results showed that constitutive BAFF mRNA expression was inhibited by Dex in a dose- and time-dependent manner. Also, Dex inhibited the secretion of BAFF in a time-dependent manner reaching 76% of inhibition 72 h after treatment. Moreover, Dex suppressed both mRNA and protein BAFF expression induced by TNF-alpha but had no effect on IFN-gamma-induced BAFF expression. In comparison with B cells cultured alone, B cells co-cultured with FLS-RA exhibited a higher survival, which was inhibited when FLS-RA were pretreated with Dex. However, the enhanced B cell survival was reestablished by the addition of rhBAFF. Therefore, Dex is a potent inhibitor of constitutive and TNF-alpha-induced BAFF expression in FLS-RA.     

Eriodictyol inhibits survival and inflammatory responses and promotes apoptosis in rheumatoid arthritis fibroblast-like synoviocytes through AKT/FOXO1 signaling

2-(3,4-Dihydroxyphenyl)-5,7-dihydroxy-2,3-dihydrochromen-4-one (eriodictyol), a flavonoid compound, was proved to possess anti-inflammatory, antioxidative, and antiarthritis activities. However, the effects of eriodictyol on the rheumatoid proliferation, apoptosis, and inflammatory response of arthritis fibroblast-like synoviocytes (RA-FLS) remain unclear. Thus, the objective of this study was to examine the effects of eriodictyol on RA-FLS survival, apoptosis, and inflammatory response, and further explore the potential underlying mechanisms. Our results showed that eriodictyol inhibited the survival of RA-FLSs and promoted its apoptosis. Eriodictyol significantly reduced RA-FLS secretion of tumor necrosis factor α, interleukin 6 (IL-6), IL-8, and IL-1β. Furthermore, eriodictyol prevented the activation of the protein kinase B (AKT) pathway and increased the expression of forkhead box O1 (FOXO1) in RA-FLS. FOXO1 silence reversed the effects of eriodictyol on RA-FLS survival, apoptosis, and inflammation. In conclusion, these findings indicated that eriodictyol inhibits the cell survival and inflammatory response in RA-FLS, and the AKT/FOXO1 signaling pathway is involved in the effect of eriodictyol on the RA-FLS. Thus, eriodictyol might be a potential therapeutic agent for the treatment of rheumatoid arthritis.     

Innate immunity triggers IL-32 expression by fibroblast-like synoviocytes in rheumatoid arthritis

Introduction  

Interleukin-32 (IL-32) is a recently described cytokine that is a strong inducer of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α, IL-1β, IL-6, and IL-8. The expression of this cytokine is highly increased in the rheumatoid synovium and correlated with the severity of joint inflammation. Little is known regarding the innate immune-related regulation of IL-32 by fibroblast-like synoviocytes (FLSs). We therefore investigated the effect of innate immune stimulation by ligands of Toll-like receptor (TLR)2, TLR3, and TLR4, and cytokines such as TNF-α and interferon (IFN)-γ, on IL-32 expression by FLSs.     

MicroRNA-192 suppresses cell proliferation and induces apoptosis in human rheumatoid arthritis fibroblast-like synoviocytes by downregulating caveolin 1

Heart disease causing cardiac cell death due to ischemia–reperfusion injury is a major cause of morbidity and mortality in the United States. Coronary heart disease and cardiomyopathies are the major cause for congestive heart failure, and thrombosis of the coronary arteries is the most common cause of myocardial infarction. Cardiac injury is followed by post-injury cardiac remodeling or fibrosis. Cardiac fibrosis is characterized by net accumulation of extracellular matrix proteins in the cardiac interstitium and results in both systolic and diastolic dysfunctions. It has been suggested by both experimental and clinical evidence that fibrotic changes in the heart are reversible. Hence, it is vital to understand the mechanism involved in the initiation, progression, and resolution of cardiac fibrosis to design anti-fibrotic treatment modalities. Animal models are of great importance for cardiovascular research studies. With the developing research field, the choice of selecting an animal model for the proposed research study is crucial for its outcome and translational purpose. Compared to large animal models for cardiac research, the mouse model is preferred by many investigators because of genetic manipulations and easier handling. This critical review is focused to provide insight to young researchers about the various mouse models, advantages and disadvantages, and their use in research pertaining to cardiac fibrosis and hypertrophy.     

Apigenin enhances the cytotoxic effects of tumor necrosis factor-related apoptosis-inducing ligand in human rheumatoid arthritis fibroblast-like synoviocytes

Activated rheumatoid arthritis (RA) fibroblast-like synoviocytes (RAFLSs) play a central role in both initiating and driving RA. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been documented to induce apoptosis only in a small proportion of RAFLSs, which is followed by an induction of proliferation in surviving cells. Apigenin, a chemopreventive bioflavonoid, exhibits proapoptotic activity in many types of cells. In the present study, we sought to determine whether apigenin could enhance the cytotoxic effect of TRAIL on activated RAFLSs. Human RAFLSs isolated from patients with RA were treated with TRAIL (1 nM), apigenin (20 μM), or their combination, and subjected to apoptosis analysis after a 24-h incubation and proliferation analysis after a 72-h incubation. Apoptosis assay revealed that TRAIL or apigenin alone induced a marked apoptosis in RAFLS and their combination yielded a synergistic increase in RAFLS apoptosis. Immunoblotting analysis of apoptosis regulators demonstrated that combined treatment with apigenin increased caspase-3 expression and activity and decreased the Bcl-2/Bax ratio relative to treatment with TRAIL alone. The presence of apigenin significantly restrained TRAIL-induced RAFLS proliferation, coupled with restoration of the expression of two cell-cycle inhibitors p21 and p27. Moreover, the combination with apigenin blunted TRAIL-induced activation of the phosphatidylinositol 3-kinase (PI3-K)/Akt pathway. Our data collectively demonstrate that apigenin sensitizes RAFLS to TRAIL-induced apoptosis and counteracts TRAIL-dependent RAFLS proliferation, which is likely mediated through inactivation of PI3-K/Akt signaling pathway.     

Astrocyte elevated gene-1 promotes inflammation and invasion of fibroblast-like synoviocytes in rheumatoid arthritis

Astrocyte elevated gene-1 (AEG-1) was initially induced by HIV-1 infection and involved in tumor progression, migration and invasion as a nuclear factor-κB (NF-κB)-dependent gene. The present study we intended to investigate the protein expression of AEG-1 significantly associated with rheumatoid arthritis. Western blot analysis and immunohistochemistry demonstrated that AEG-1 was upregulated in synovial tissue of RA patients compared with the controls. Double immunofluorescent staining suggested that AEG-1 was expressed in fibroblast-like synoviocytes (FLS) of RA patients. Furthermore, the expression of AEG-1 in FLS was increased in time-dependent manner by TNF-α stimulation. Upon TNF-α-treated FLS, AEG-1 transferred from the cytoplasm to nucleus where it interacted with the p65 subunit of NF-κB, as examined by immunoprecipitation and immunofluorescent staining assay. Moreover, the inhibition of AEG-1 by RNA interference significantly suppressed TNF-α-induced IL-6 and MMP-3 expression, leading to attenuation of FLS migration and invasion and markedly decreased the phosphorylation of P65 and IκBα, as well as AKT in FLS. Collectively, Our findings provided evidence that AEG-1 contributed to the production of inflammatory cytokines, migration and invasion of RA FLS, and underscored the importance of AEG-1 in the inflammation process of RA.     

Geldanamycin induces apoptosis and inhibits inflammation in fibroblast-like synoviocytes isolated from rheumatoid arthritis patients

Rheumatoid arthritis (RA) is an autoimmune disease of the joints characterized by synovial hyperplasia and chronic inflammation. Fibroblasts-like synoviocytes (FLS), major cells in the synovium, together with infiltrated leukocytes, contribute greatly to RA progression. In our study, we hypothesized that geldanamycin (GA), a cancer drug might be able to inhibit RA FLS growth. To test the idea, RA FLS were isolated and cultured for cancer drug test. The results showed that GA can specifically inhibit the growth of RA FLS compared with normal FLS. Essentially, GA was found to promote reactive oxygen species production in RA FLS and induce programmed cell death. The annexinV/propidium iodide and terminal deoxynucleotidyl transferase dUTP nick-end labeling staining confirmed that GA can directly induce apoptosis and subsequently inhibit the growth of RA FLS, which was also confirmed by Western blot assay. In addition, our data demonstrated that inflammation was inhibited by suppressed nuclear factor κB signaling pathway. The therapeutic effect of GA was explored in collagen-induced arthritis mice. In short, GA was a promising drug for the treatment of RA by specifically inhibiting the proliferation and inflammation of RA FLS.     

佐剂诱导关节炎大鼠模型的建立及成纤维样滑膜细胞的分离

目的建立类风湿性关节炎（RA）动物模型;从炎性关节滑膜中分离成纤维样滑膜细胞（FLS）。方法应用热灭活结核杆菌H37Ra菌株与矿物油混合制备改良的佐剂,尾根部皮内注射Lewis大鼠诱导关节炎;剪取成功诱导关节炎大鼠的病变踝关节,从中剥离滑膜组织,充分剪碎后采用胶原酶消化法分离成纤维样滑膜细胞。结果成功诱导了大鼠关节炎,发病率为100%,发病时间有规律,组织学表现与RA相似;成功在体外培养了FLS并对其进行了鉴定,掌握了其生长形态和特征。结论成功制备RA动物模型并获得FLS,为今后RA发病机制探索和药物评价提供了良好的体内动物模型和体外细胞模型。     

Sirt2 suppresses inflammatory responses in collagen-induced arthritis

Arthritis is a common autoimmune disease that is associated with progressive disability, systemic complications and early death. However, the underling mechanisms of arthritis are still unclear. Sirtuins are a NAD⁺-dependent class III deacetylase family, and regulate cellular stress, inflammation, genomic stability, carcinogenesis, and energy metabolism. Among the sirtuin family members, Sirt1 and Sirt6 are critically involved in the development of arthritis. It remains unknown whether other sirtuin family members participate in arthritis. Here in this study, we demonstrate that Sirt2 inhibits collagen-induced arthritis (CIA) using in vivo and in vitro evidence. The protein and mRNA levels of Sirt2 significantly decreased in joint tissues of mice with CIA. When immunized with collagen, Sirt2-KO mice showed aggravated severity of arthritis based on clinical scores, hind paw thickness, and radiological and molecular findings. Mechanically, Sirt2 deacetylated p65 subunit of nuclear factor-kappa B (NF-κB) at lysine 310, resulting in reduced expression of NF-κB-dependent genes, including interleukin 1β (IL-1β), IL-6, monocyte chemoattractant protein 1(MCP-1), RANTES, matrix metalloproteinase 9 (MMP-9) and MMP-13. Importantly, our rescue experiment showed that Sirt2 re-expression abated the severity of arthritis in Sirt2-KO mice. Those findings strongly indicate Sirt2 as a considerably inhibitor of the development of arthritis.     

Complement deficiency ameliorates collagen-induced arthritis in mice

Collagen-induced arthritis (CIA) is an experimental animal model of human rheumatoid arthritis being characterized by synovitis and progressive destruction of cartilage and bone. CIA is induced by injection of heterologous or homologous collagen type II in a susceptible murine strain. DBA/1J mice deficient of complement factors C3 (C3(-/-)) and factor B (FB(-/-)) were generated to elucidate the role of the complement system in CIA. When immunized with bovine collagen type II emulsified in CFA, control mice developed severe arthritis and high CII-specific IgG Ab titers. In contrast, the C3(-/-) and FB(-/-) were highly resistant to CIA and displayed decreased CII-specific IgG Ab response. A repeated bovine collagen type II exposure 3 wk after the initial immunization led to an increase in the Ab response in all mice and triggered arthritis also in the complement-deficient mice. Although the arthritic score of the C3(-/-) mice was low, the arthritis in FB(-/-) mice ranked intermediate with regard to C3(-/-) and control mice. We conclude that complement activation by both the classical and the alternative pathway plays a deleterious role in CIA.     

Guggulsterone blocks IL-1beta-mediated inflammatory responses by suppressing NF-kappaB activation in fibroblast-like synoviocytes

Guggulsterone is a plant sterol that is used to treat hyperlipidemia, arthritis, and obesity. Although its anti-inflammatory and anti-hyperlipidemic effects have been well documented, the effect of guggulsterone on fibroblast-like synoviocytes (FLS) has not yet been reported. Therefore, in this study, the effect of guggulsterone on interleukin (IL)-1beta-induced inflammatory responses in the FLS of rheumatic patients was investigated. Treatment of FLS with IL-1beta induced production of chemokines such as RANTES and ENA-78. In addition, Western blot analysis and gelatin zymography revealed that IL-1beta activated matrix metalloproteinase (MMP)-1 and -3 in FLS. However, pre-incubation with guggulsterone completely inhibited the ability of IL-1beta to induce the production of chemokines and to activate MMPs. Although the NF-kappaB binding activity and nuclear p50 and p65 subunit levels, as well as IkappaBalpha degradation in the cytoplasm was greater in cells stimulated with IL-1beta than in unstimulated cells, treatment with guggulsterone abolished all of these increases. Collectively, these results suggest that guggulsterone would be useful as an inhibitor of joint destruction in patients with rheumatoid arthritis.