Mediators of inflammation-induced bone damage in arthritis and their control by herbal products

Exploring the gut microbiome: probiotics, prebiotics, synbiotics, and postbiotics as key players in human health and disease improvement

The human gut microbiome accompanies us from birth, and it is developed and matured by diet, lifestyle, and environmental factors. During aging, the bacterial composition evolves in reciprocal communication with the host's physiological properties. Many diseases are closely related to the gut microbiome, which means the modulation of the gut microbiome can promote the disease targeting remote organs. This review explores the intricate interaction between the gut microbiome and other organs, and their improvement from disease by prebiotics, probiotics, synbiotics, and postbiotics. Each section of the review is supported by clinical trials that substantiate the benefits of modulation the gut microbiome through dietary intervention for improving primary health outcomes across various axes with the gut. In conclusion, the review underscores the significant potential of targeting the gut microbiome for therapeutic and preventative interventions in a wide range of diseases, calling for further research to fully unlock the microbiome's capabilities in enhancing human health.

MicroRNAs-mediated regulation pathways in rheumatic diseases

Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are two common rheumatic disorders marked by persistent inflammatory joint disease. Patients with RA have osteodestructive symptoms, but those with AS have osteoproliferative manifestations. Ligaments, joints, tendons, bones, and muscles are all affected by rheumatic disorders. In recent years, many epigenetic factors contributing to the pathogenesis of rheumatoid disorders have been studied. MicroRNAs (miRNAs) are small, non-coding RNA molecules implicated as potential therapeutic targets or biomarkers in rheumatic diseases. MiRNAs play a critical role in the modulation of bone homeostasis and joint remodeling by controlling fibroblast-like synoviocytes (FLSs), chondrocytes, and osteocytes. Several miRNAs have been shown to be dysregulated in rheumatic diseases, including miR-10a, 16, 17, 18a, 19, 20a, 21, 27a, 29a, 34a, 103a, 125b, 132, 137, 143, 145, 146a, 155, 192, 203, 221, 222, 301a, 346, and 548a.The major molecular pathways governed by miRNAs in these cells are Wnt, bone-morphogenic protein (BMP), nuclear factor (NF)-κB, receptor activator of NF-κB (RANK)-RANK ligand (RANKL), and macrophage colony-stimulating factor (M-CSF) receptor pathway. This review aimed to provide an overview of the most important signaling pathways controlled by miRNAs in rheumatic diseases.

The Use of Polymers to Enhance Post-Orthodontic Tooth Stability

Relapse after orthodontic treatment occurs at a rate of about 70 to 90%, and this phenomenon is an orthodontic issue that has not yet been resolved. Retention devices are one attempt at prevention, but they require a considerable amount of time. Most orthodontists continue to find it challenging to manage orthodontic relapse; therefore, additional research is required. In line with existing knowledge regarding the biological basis of relapse, biomedical engineering approaches to relapse regulation show promise. With so many possible uses in biomedical engineering, polymeric materials have long been at the forefront of the materials world. Orthodontics is an emerging field, and scientists are paying a great deal of attention to polymers because of their potential applications in this area. In recent years, the controlled release of bisphosphonate risedronate using a topically applied gelatin hydrogel has been demonstrated to be effective in reducing relapse. Simvastatin encapsulation in exosomes generated from periodontal ligament stem cells can promote simvastatin solubility and increase the inhibitory action of orthodontic relapse. Moreover, the local injection of epigallocatechin gallate-modified gelatin suppresses osteoclastogenesis and could be developed as a novel treatment method to modify tooth movement and inhibit orthodontic relapse. Furthermore, the intrasulcular administration of hydrogel carbonated hydroxyapatite-incorporated advanced platelet-rich fibrin has been shown to minimize orthodontic relapse. The objective of this review was to provide an overview of the use of polymer materials to reduce post-orthodontic relapse. We assume that bone remodeling is a crucial factor even though the exact process by which orthodontic correction is lost after retention is not fully known. Delivery of a polymer containing elements that altered osteoclast activity inhibited osteoclastogenesis and blocking orthodontic relapse. The most promising polymeric materials and their potential orthodontic uses for the prevention of orthodontic relapse are also discussed.

Palmul-Tang, a Korean Medicine, Promotes Bone Formation via BMP-2 Pathway in Osteoporosis

Osteoporosis is a common skeletal disease in post-menopausal women. Palmul-tang, an herbal medicine, has been treated for gynecological disease such as anemia, anorexia, anti-fatigue, unspecified menstruation and female infertility in East Asia. In this study, ameliorative effects of Palmul-tang soft extracts (PMT), a Korean Medicine, on osteoporosis were investigated. Ovariectomized (OVX) osteoporotic ICR mice were intragastrically administrated PMT for 4 weeks. The level of bone mineral density (BMD) was analyzed in bone tissues by dual X-ray absorptiometry. The bone medullary cavity and deposition of collagen were investigated by histological analysis. In addition, the BMP-2 signaling-related molecules, osteoblastic differentiation and formation markers, were determined in femoral tissues. The levels of BMD and bone mineral content were significantly increased in tibia, femurs and LV by treatment of PMT. PMT replenished bone marrow cavity and increased collagen deposition in bone marrow cells of femur. In addition, administration of PMT recovered serum ALP, bALP, osteocalcin and calcium levels in osteoporotic mice. Moreover, PMT treatment up-regulated the expressions of BMP-2, RUNX2 and OSX with its downstream factors, ALP, OPN and BSP-1, in the femoral tissues. Taken together, PMT restored the bone minerals and improvement of bone integrity by bone-forming BMP-2 signaling pathway. These results demonstrate that PMT could be an ameliorative agent for osteoporosis.

Effect of Carbonate Apatite Hydrogel-Advanced Platelet-Rich Fibrin Injection on Osteoblastogenesis during Orthodontic Relapse in Rabbits

Objective  This study aimed to determine the effect of carbonate apatite (CHA) hydrogel-aPRF on osteoblastogenesis during relapse in rabbits.

Materials and Methods  Forty-five rabbits were divided into three groups ( n = 15): the control, CHA, and CHA-autologous platelet-rich fibrin (aPRF) groups. An open-coil spring was compressed between brackets to distalize the lower incisors of the rabbits by delivering a force of 50 cN for 1 week. The new position of the teeth was retained for 14 days, and CHA hydrogel-aPRF was injected every 7 days. The appliances were then debonded to allow relapse. On days 0, 3, 7, 14, and 21 after debonding, transforming growth factor (TGF)-β1 and bone morphogenetic protein (BMP)-2 expression was examined using immunohistochemistry staining and Runx-2 levels were analyzed by enzyme-linked immunosorbent assay. The data collected were analyzed using analysis of variance and a post hoc Tukey’s test ( p < 0.05).

Results  Histomorphometric analysis revealed that TGF-β1 expression in the CHA-aPRF group is statistically higher than that in other groups on days 0, 3, and 7 after debonding ( p < 0.05). BMP-2 expression in the CHA-aPRF group was also statistically higher than that in the other groups on days 3, 14, and 21 after debonding ( p < 0.05). ELISA showed that Runx-2 levels are slightly higher in the CHA-aPRF group than in the other groups ( p > 0.05).

Conclusion  Although injection of CHA-aPRF aids in osteoblastogenesis associated with enhancing TGF-β1 and BMP-2 expressions, it does not significantly upregulate Runx-2 levels.

Yunnan Baiyao diminishes lipopolysaccharide-induced inflammation in osteoclasts

Yunnan Baiyao (YNBY) has been refined for hundreds of years and has become a treasure of proprietary Chinese medicine that has significant curative effects in the field of hemostasis, blood circulation, and callus. In past years, YNBY has been demonstrated to play an anti-inflammatory role in bone-related diseases, such as rheumatoid arthritis and osteoporosis. However, the osteoclasts are multinucleated giant cells that resorb bone and participate in the occurrence, development, and progression of these bone-related diseases. Previous studies have reported that the inflammatory function is closely associated with arachidonic acid (AA) metabolism, as well as some inflammatory-related pathways, including the nuclear factor кB (NF-кB), mitogen-activated protein kinase (MAPK), and Wnt5a pathways. Therefore, we speculated that the anti-inflammatory effect of YNBY might be associated with the NF-кB, MAPK, and Wnt5a pathways. In order to further excavate the anti-inflammatory roles of YNBY, lipopolysaccharide (LPS) with an optimal concentration of 1,000 pg/ml was used to induce inflammation in osteoclasts. Our results showed that YNBY with a time- and dose-dependent method decreased the concentration of pro-inflammatory cytokines and the expression levels of cyclooxygenase-1 (COX-1), COX-2, 5-lipoxygenase, and prostaglandin E2. Moreover, it was found that COX-2 was the target gene regulated by YNBY. Finally, using NF-кB and MAPK pathway inhibitors or miRNA101b (involved in the Wnt5a pathway) in tandem with YNBY and the results exhibited that these groups caused a reduction in COX-1 and COX-2 expression, indicating that the anti-inflammatory function of YNBY might directly affect the NF-кB, MAPK, and Wnt5a pathways. PRACTICAL APPLICATIONS: Yunnan Baiyao (YNBY) is mainly extracted from precious Chinese medicines such as Panax notoginseng, borneol, musk, and yam and has a wide range of clinical applications. It is not only used to treat various types of traumatic injuries, but also used for upper gastrointestinal bleeding and wound ulcers, neonatal umbilitis, recurrent oral ulcers, esophagitis, bacterial dysentery, and so on. Although the detailed mechanism of action is not clear at present, it is believed that this is related to its anti-inflammatory, hemostatic, and immune-enhancing effects. Many bone-related diseases, such as rheumatoid arthritis and osteoporosis, are regarded to be intimately related to the inflammatory reaction. Thus, this study aimed to explore the underlying mechanisms of YNBY at anti-inflammatory roles. And our results suggested that YNBY directly affected the inflammatory cytokines and AA metabolic products which referred to the NF-кB, MAPK, and Wnt5a pathways, as well as AA metabolism, respectively. Hence, the practical applications of YNBY are the anti-inflammatory effects used to treat for bone-related diseases.

Immunomodulating action of the 3-phenylcoumarin derivative 6,7-dihydroxy-3-[3',4'-methylenedioxyphenyl]-coumarin in neutrophils from patients with rheumatoid arthritis and in rats with acute joint inflammation

OBJECTIVE

To examine whether free (3-PD-5_free) and/or liposomal (3-PD-5_lipo) 6,7-dihydroxy-3-[3',4'-methylenedioxyphenyl]-coumarin (3-PD-5) (1) modulate the effector functions of neutrophils from patients with rheumatoid arthritis under remission (i-RA) and with active disease (a-RA), in vitro; and (2) exert anti-inflammatory effect in a rat model of zymosan-induced acute joint inflammation.

METHODS AND RESULTS

Incorporation of 3-PD-5 into unilamellar liposomes of soya phosphatidylcholine and cholesterol was efficient (57.5 ± 7.9%) and yielded vesicles with low diameter (133.7 ± 18.4 nm), polydispersity index (0.39 ± 0.06), and zeta potential (- 1.22 ± 0.34 mV). 3-PD-5_free (1 µM) and 3-PD-5_lipo (3 µM) equally suppressed elastase release and reactive oxygen species generation in neutrophils from healthy subjects and i-RA and a-RA patients, stimulated with immune complexes. 3-PD-5_free (20 µM) suppressed the release of neutrophil extracellular traps and chemotaxis in vitro, without clear signs of cytotoxicity. 3-PD-5_lipo (1.5 mg/kg, i.p.) diminished joint edema and synovial infiltration of total leukocytes and neutrophils, without changing the synovial levels of TNF-α, IL-1β, and IL-6.

CONCLUSION

Altogether, the results reported herein indicate that 3-PD-5 is a promising modulator of the early stages of acute joint inflammation that can help to diminish not only excessive neutrophil infiltration in the synovia but also neutrophil activation and its outcomes in RA patients.

Anti-rheumatoid activity of ethanolic extract of Sesamum indicum seed extract in Freund's complete adjuvant induced arthritis in Wistar albino rats

Sesamum indicum, one of the first recorded plants used for its seeds, is reported to have analgesic, antioxidant, anticancer, anti-obesity as well as hepato and nephro protective activities. The current study evaluated the effects of two doses (400 and 800 mg/kg) of ethanolic extract of S. indicum seeds in Freund's complete adjuvant induced arthritis in rats in comparison with diclofenac and methotrexate by the changes produced in body weight, body temperature, paw volume and spontaneous activity, hemoglobin, erythrocyte sedimentation rate, total white blood cells, red blood cells, Interleukin-6 and Tumor necrosis factor-α as well as joint changes in X-ray and histological changes in joint tissue. Unlike the untreated group, the groups treated with S. indicum showed significant decrease in paw volume, body weight, white blood cell count, erythrocyte sedimentation rate, Interleukin-6 and Tumor necrosis factor-α and an increase in body weight, spontaneous activity, hemoglobin level, and red blood cell count. Histopathological examination showed gross reduction in synovial inflammation and cartilage damage. X-ray revealed significant improvement in joint space. The effect of ethanolic extract of S. indicum was found to be equivalent to methotrexate and greater than diclofenac.

Paeoniflorin regulates osteoclastogenesis and osteoblastogenesis via manipulating NF-κB signaling pathway both in vitro and in vivo

The metabolic balance between synthesis and resorption of the bone is maintained by osteoblasts and osteoclasts, respectively. Identification of agents that stimulate bone formation and suppress excessive osteoclast formation, may aid in preventing and treating conditions like osteoporosis and periprosthetic loosening. Paeoniflorin is a natural product derived from Paeonia lactiflora Pall with anti-inflammatory, analgesic, and diuretic properties. However, the effect of paeoniflorin on osteoclastogenesis and osteoblastogenesis is unknown. Herein, we demonstrated that paeoniflorin has a dose-dependent suppressive action on RANKL-evoked osteoclast differentiation and bone resorption, achieved by inhibiting the NF-κB pathway and subunit p65 nuclear translocation. Simultaneously, paeoniflorin was also found to stimulate osteoblast differentiation and bone mineralization, in addition to rescuing TNFα-impaired osteoblastogenesis. At the molecular level, paeoniflorin was found to inhibit NF-κB transcriptional activity and stimulate osteoblastogenesis-related marker gene expression (ALP, osteocalcin, OPN and Runx2), a trend that was inhibited by p65 overexpression. In ovariectomized mice, paeoniflorin was found to improve osteoblast activity, inhibit osteoclast activity, and thus, reduce ovariectomy-induced osteoporosis. Our study demonstrated that paeoniflorin simultaneously suppressed osteoclastogenesis and facilitated osteoblastogenesis by manipulating the actions of NF-κB. Therefore, paeoniflorin may serve as an ideal therapeutic antidote for osteoporosis.

Pilose antler peptide potentiates osteoblast differentiation and inhibits osteoclastogenesis via manipulating the NF-κB pathway

Bones are inflexible yet ever-changing metabolic organs, and bone homeostasis is maintained through two delicately regulated processes: bone construction and bone reabsorption. An imbalance in bone metabolism is linked to most orthopedic diseases, including osteoporosis and rheumatoid arthritis. Importantly, tumor necrosis factor-α (TNF-α) blocks osteoblast differentiation and stimulates osteoclast formation, resulting in delayed deposition of new bone and accelerated bone resorption, especially in rheumatoid arthritis patients with inflammatory conditions. Pilose antler peptide (PAP) isolated and purified from deer antlers has been shown to have beneficial effects on chronic inflammation. In the present study, we studied the impact of PAP on osteoblast differentiation and evaluated the regulatory mechanism, with particular emphasis on the effect of PAP on TNF-α-mediated NF-κB signaling. Mouse primary osteoblast cells were activated with bone morphogenetic protein-2 (BMP-2) for osteoblast differentiation. A significant stimulatory effect of PAP in osteoblastogenesis was observed using ALP activity and Alizarin Red S staining assays. Meanwhile, PAP significantly rescued TNF-α-induced impairment of osteoblast formation as well as mineralization. Furthermore, we found a similar trend upon analyzing osteoblast-specific gene expression. PAP significantly rescued TNF-α-mediated decrease in expression of osteoblast-specific genes. A molecular mechanism assay indicated that PAP significantly inhibited TNF-α-mediated stimulation of NF-κB signaling activity, as well as nuclear translocation of its subunit p65. Moreover, over-expression of p65 reversed the stimulatory effects of PAP on osteoblast differentiation. Furthermore, we also identified that PAP dose dependently inhibit osteoclastogenesis, and this effect might be achieved via suppressing NF-κB activity. In summary, this study shows that PAP promotes osteoblast differentiation and blocks TNF-α-mediated suppression of osteoblastogenesis in vitro via the NF-κB/p65 pathway, as well as inhibits osteoclastsogenesis in vitro. Therefore, PAP, a novel drug with both antiresorptive and osteoanabolic activity, shows therapeutic potential as an alternative treatment for osteolytic diseases, including rheumatoid arthritis and osteoporosis.

Modulation of Inflammatory Response to Implanted Biomaterials Using Natural Compounds

Tissue engineering offers a promising strategy to restore injuries resulting from trauma, infection, tumor resection, or other diseases. In spite of significant progress, the field faces a significant bottleneck; the critical need to understand and exploit the interdependencies of tissue healing, angiogenesis, and inflammation. Inherently, the balance of these interacting processes is affected by a number of injury site conditions that represent a departure from physiological environment, including reduced pH, increased concentration of free radicals, hypoglycemia, and hypoxia. Efforts to harness the potential of immune response as a therapeutic strategy to promote tissue repair have led to identification of natural compounds with significant anti-inflammatory properties. This article provides a concise review of the body's inflammatory response to biomaterials and describes the role of oxygen as a physiological cue in this process. We proceed to highlight the potential of natural compounds to mediate inflammatory response and improve host-graft integration. Herein, we discuss the use of natural compounds to map signaling molecules and checkpoints that regulate the cross-linkage of immune response and skeletal repair.

Association of Respiratory Tuberculosis with Incident Bone Fracture: Bridging the Tuberculosis Airway Infection and the Osteoporotic Bone

Objective

The relationship between respiratory tuberculosis (RT) and incident fragility fracture and osteoporosis/fragility fracture in the general population is not well determined; therefore, we conducted a nationwide cohort study to investigate this relationship.

Methods

We used the National Health Insurance Research Database of Taiwan to identify 6612 newly diagnosed patients with RT (RT cohort) and 13220 patients without RT (non-RT cohort) from 1999 to 2005. The mean durations of follow-up were (6.73 ± 4.00 years, 8.11 ± 3.24 years) in the (RT cohort, non- RT cohort); respectively. The occurrence of incident fragility fracture and osteoporosis/fragility fracture were followed up until the end of 2011. The adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) and 98% CIs of incident fragility fracture and osteoporosis/fragility fracture were estimated using the multivariable Cox proportional hazard model after adjusting for age, sex, occupation, drug use, and comorbidities.

Results

A Cox proportional hazards regression analysis was performed and showed the aHRs of [incident fragility fracture; osteoporosis/fragility fracture] were [1.69 (95% CI = 1.26–2.28, 98% CI = 1.18–2.44); 1.42 (95% CI = 1.25–1.61, 98% CI = 1.21–1.65)] between the RT and non-RT cohorts. Regarding the sex, the aHRs of the [incident fragility fracture; osteoporosis / fragility fracture] were [1.57 (98% CI = 1.10–2.23, 98% CI = 1.02–2.41); 1.15 (95% CI = 0.97–1.36, 98% CI = 0.94–1.41)] in the men. The aHRs of the RT cohort without oral steroid use in the [incident fragility fracture; osteoporosis / fragility fracture] were [1.87 (95% CI = 1.20–2.90, 98% CI = 1.09–3.19); 1.41 (95% CI = 1.19–1.67, 98% CI = 1.14–1.74)].

Conclusion

The RT associated with the incident fragility fracture, either in men or absence of oral steroid use.

Periploca forrestii Saponin Ameliorates Murine CFA-Induced Arthritis by Suppressing Cytokine Production

Periploca forrestii Schltr. has been used as a Chinese folk medicine due to its versatile pharmacological effects such as promoting wounds and rheumatoid arthritis. However, the antiarthritic activity of Periploca forrestii saponin (PFS) and its active compound Periplocin has still not been demonstrated. Here, we evaluated the antiarthritic effects of PFS in adjuvant-induced arthritis (AIA) rats by intragastric administration at a dose of 50 mg/kg. The anti-inflammatory activities of Periplocin were also examined in LPS-induced AIA splenocytes and synoviocytes. PFS significantly ameliorated joint swelling; inhibited bone erosion in joints; lowered levels of IL-6 and TGF-β1 in AIA rat splenocyte; and reduced joint protein expression levels of phospho-STAT3 and IKKα. Using LPS-induced AIA splenocytes, we demonstrate that Periplocin suppressed the key proinflammatory cytokines levels of IL-6, IFN-γ, TGF-β1, and IL-13 and IL-22 and transcription factor levels of T-bet, GATA3, and C-Jun genes. Periplocin also suppressed LPS-induced cytokine secretion from synoviocytes. Our study highlights the antiarthritic activity of PFS and its derived Periplocin and the underlying mechanisms. These results provide a strong rationale for further testing and validation of the use of Periploca forrestii Schltr. as an alternative modality for the treatment of RA.

Cat's whiskers (Orthosiphon stamineus) tea modulates arthritis pathogenesis via the angiogenesis and inflammatory cascade

Background

Orthosiphon stamineus is used traditionally to treat gout, arthritis, and inflammatory related conditions. The in vitro anti-inflammatory effects of the plant have been scientifically investigated. The goal of the present study was to evaluate the potential of the 50% ethanol extract of O. stamineus (EOS) to treat rheumatoid arthritis.

Methods

Anti-arthritic activity was assessed using the in vitro heat denaturation test and the (FCA)-induced arthritis model. Efficacy was assessed by measurements of paw edema and granulation, X-ray radiography, fluorescence molecular tomography (FMT), and histological evaluation. Levels of (TNF-α), interleukin-1 (IL-1), and (COX-1 and COX-2) were analyzed in vitro in lipopolysaccharide (LPS)-stimulated human macrophage (U937). TNF-α and IL-1 levels in the serum samples of arthritic rats were also measured using an ELISA kit.

Results

Treatment with EOS resulted in dose-dependent inhibition of paw edema in acute and chronic models of inflammation. It also inhibited significantly the production of TNF-α, IL-1 COX-1, and COX-2 in the LPS-stimulated U937 macrophages. EOS significantly suppressed FCA-induced paw edema as well as the serum levels of TNF-α and IL-1. X-rays of the synovial joint of the hind leg showed considerable improvement in joint integrity and recovery of tibia-talus bones from degeneration and osteoporotic lesions. Histology of proximal interphalangeal joints of EOS-treated animals showed obvious protection of cartilage and soft tissue. Finally, FMT analysis strongly supported the anti-arthritic effect of EOS. EOS had high phenolic and total flavonoid content as well as strong antioxidant activity.

Conclusions

Results illustrated that the anti-arthritic properties of O. stamineus could be beneficial for prevention and management of rheumatoid arthritis and other chronic inflammatory disorders.

Graphical abstract

Illustration of the Anti- arthritis efficacy of Orthosiphon Stamineus standardized extract.

Celastrol modulates inflammation through inhibition of the catalytic activity of mediators of arachidonic acid pathway: Secretory phospholipase A2 group IIA, 5-lipoxygenase and cyclooxygenase-2

Elevated production of arachidonic acid (AA)-derived pro-inflammatory eicosanoids due to the concerted action of secretory phospholipase A₂ group IIA (sPLA₂IIA), 5-lipoxygenase (5-LOX) and cyclooxygenase-2 (COX-2) is a common feature of many inflammatory disorders. Hence, modulation of the bioactivity of these 3 enzymes is an important strategy to control inflammation. However, the failure of drugs specific for an individual enzyme (sPLA₂IIA-, 5-LOX- or COX-2) and the success of 5-LOX/COX-2 dual inhibitors in effectively controlling inflammation in clinical trials prompted us to evaluate a common inhibitor for sPLA₂IIA, 5-LOX and COX-2 enzymes. Celastrol, a quinone methide triterpene, was selected in this regard through molecular docking studies. We provide the first evidence for celastrol's ability to inhibit the catalytic activity of sPLA₂IIA, 5-LOX and COX-2 enzymes. Celastrol significantly inhibited the catalytic activity of sPLA₂IIA (IC₅₀=6μM) in vitro, which is independent of substrate and calcium concentration. In addition, celastrol inhibited the catalytic activities of 5-LOX (IC₅₀=5μM) and COX-2 (IC₅₀=20μM) in vitro; sPLA₂IIA-induced edema and carrageenan-induced edema in mice; and lipopolysaccharide-stimulated production of PGE₂ in human neutrophils. Thus, celastrol modulates inflammatory responses by targeting multiple enzymes of AA pathway.

Rocaglamide-A Potentiates Osteoblast Differentiation by Inhibiting NF-κB Signaling

Rheumatoid arthritis is a chronic inflammatory disease that leads to bone and cartilage erosion. The inhibition of osteoblast differentiation by the inflammatory factor TNF-α is critical for the pathogenesis of rheumatoid arthritis. To modulate TNF-α mediated inhibition of osteoblast differentiation is required to improve therapeutic efficacy of rheumatoid arthritis. Here, we explored the potential role of rocaglamide-A, a component of Aglaia plant, in osteoblast differentiation. Rocaglamide-A prevented TNF-α mediated inhibition of osteoblast differentiation, and promoted osteoblast differentiation directly, in both C2C12 and primary mesenchymal stromal cells. Mechanistically, Rocaglamide-A inhibited the phosphorylation of NF-κB component p65 protein and the accumulation of p65 in nucleus, which resulted in the diminished NF-κB responsible transcriptional activity. Oppositely, overexpression of p65 reversed rocaglamide-A's protective effects on osteoblast differentiation. Collectively, rocaglamide-A protected and stimulated osteoblast differentiation via blocking NF-κB pathway. It suggests that rocaglamide-A may be a good candidate to develop as therapeutic drug for rheumatoid arthritis associated bone loss diseases.

Tinospora cordifolia inhibits autoimmune arthritis by regulating key immune mediators of inflammation and bone damage

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation of the joints leading to tissue damage. Despite the availability of potent drugs including the biologics, many patients fail to respond to them, whereas others suffer adverse effects following long-term use of these drugs. Accordingly, the use of natural herbal products by RA patients has been increasing over the years. However, limited information about the mechanism of action of these natural products is a major shortcoming that prevents the widespread acceptance of herbal therapy by professionals and patients alike. In this study, we demonstrated the anti-arthritic activity of Tinospora cordifolia extract (TCE) using the rat adjuvant-induced arthritis model of human RA and elaborated the immune mechanisms underlying this effect. TCE treatment suppressed arthritic inflammation and bone and cartilage damage. The anti-inflammatory effect of TCE was mediated via reduction of the pro-inflammatory cytokines such as: IL-1β, TNF-α, IL-6, and IL-17; the frequency of IL-17-producing T cells; and the production of chemokines such as RANTES. Furthermore, TCE treatment limited bone damage by shifting the balance of mediators of bone remodeling (e.g., receptor activator of nuclear factor-kB ligand [RANKL] and MMP-9) in favor of anti-osteoclastic activity. Our results suggest that TCE and its bioactive components should be evaluated for their utility as therapeutic adjuncts to conventional drugs against RA.

Effects of agkistrodon in different dosage forms on collagen-induced arthritis in rats

OBJECTIVE

To determine the effective dosage and formulation of agkistrodon in collagen-induced arthritis (CIA) rats.

METHODS

CIA was induced by injection of collagen in complete/incomplete Freund's adjuvant. Agkistrodon decoction, agkistrodon powder, and agkistrodon wine were administered daily starting from the onset of arthritis. Paw swelling degree was measured by using a volume-measuring instrument every 7 days after primary immunization. Arthritis index was measured and calculated using the "five scoring method" every 7 days. The levels of serum interleukin-1ß (IL-1ß) and type II collagen IgG antibodies were detected by enzyme-linked immunosorbent assay. Finally, all ankles were removed, and X-ray radiography was performed with In-vivo Imaging System FX. Samples were counterstained with hematoxylin and eosin for analysis.

RESULTS

Among the various dosage formulations of agkistrodon, high-dose powder, which was equivalent to an amount of 6 g/day in adults, showed better effects on the inhibition of joint swelling and reduction of arthritis index score. The relatively low levels of serum IL-1 and anti-type II collagen IgG antibodies, as well as the X-ray radiography and pathology results, further proved the superiority of the high-dose powder over the other formulations. The effect of decoction on inhibiting joint swelling was inversely proportional to the dosage. Other effects, such as reduction of arthritis index score and the levels of serum IL-1 and anti-type II collagen IgG antibodies, were directly proportional to the dosage. While the use of large dose agkistrodon wine led to negative effects.

CONCLUSION

These data highlight the potential function of high-dose agkistrodon powder, which was equivalent to an amount of 6 g/day in adults. The powder can quickly relieve the symptoms of rheumatoid arthritis and prevent aggravation of disease, especially during the early period.

Fcγ and Complement Receptors and Complement Proteins in Neutrophil Activation in Rheumatoid Arthritis: Contribution to Pathogenesis and Progression and Modulation by Natural Products

Rheumatoid arthritis (RA) is a highly disabling disease that affects all structures of the joint and significantly impacts on morbidity and mortality in RA patients. RA is characterized by persistent inflammation of the synovial membrane lining the joint associated with infiltration of immune cells. Eighty to 90% of the leukocytes infiltrating the synovia are neutrophils. The specific role that neutrophils play in the onset of RA is not clear, but recent studies have evidenced that they have an important participation in joint damage and disease progression through the release of proteolytic enzymes, reactive oxygen species (ROS), cytokines, and neutrophil extracellular traps, in particular during frustrated phagocytosis of immune complexes (ICs). In addition, the local and systemic activation of the complement system contributes to the pathogenesis of RA and other IC-mediated diseases. This review discusses (i) the participation of Fcγ and complement receptors in mediating the effector functions of neutrophils in RA; (ii) the contribution of the complement system and ROS-dependent and ROS-independent mechanisms to joint damage in RA; and (iii) the use of plant extracts, dietary compounds, and isolated natural compounds in the treatment of RA, focusing on modulation of the effector functions of neutrophils and the complement system activity and/or activation.

Involvement of the IL-23/IL-17 axis and the Th17/Treg balance in the pathogenesis and control of autoimmune arthritis

The T helper (Th) cell subsets are characterized by the type of cytokines produced and the master transcription factor expressed. Th1 cells participate in cell-mediated immunity, whereas Th2 cells promote humoral immunity. Furthermore, the two subsets can control each other. Thereby, Th1-Th2 balance offered a key paradigm in understanding the induction and regulation of immune pathology in autoimmune and other diseases. However, over the past decade, Th17 cells producing interleukin-17 (IL-17) have emerged as the major pathogenic T cell subset in many pathological conditions that were previously attributed to Th1 cells. In addition, the role of CD4+CD25+T regulatory cells (Treg) in controlling the activity of Th17 and other T cell subsets has increasingly been realized. Thereby, examination of the Th17/Treg balance in the course of autoimmune diseases has significantly advanced our understanding of the pathogenesis of these disorders. The differentiation of Th17 and Treg cells from naïve T cells is inter-related and controlled in part by the cytokine milieu. For example, transforming growth factor β (TGFβ) is required for Treg induction, whereas the same cytokine in the presence of IL-6 (or IL-1) promotes the differentiation of Th17. Furthermore, IL-23 plays a role in the maintenance of Th17. Accordingly, novel therapeutic approaches are being developed to target IL-23/IL-17 as well as to modulate the Th17/Treg balance in favor of immune regulation to control autoimmunity.

Effect of methotrexate upon antigen-induced arthritis of the rabbit temporomandibular joint

BACKGROUND

Juvenile idiopathic arthritis (JIA) of the temporomandibular joint (TMJ) can cause severe growth disturbances of the craniomandibular system. Antigen-induced arthritis (AIA) of the rabbit TMJ is simulating the inflammatory process of the TMJ in JIA. The aim of this study was to investigate the effect of a systemic administration of methotrexate (MTX) on AIA in rabbits by means of three different histological staining methods.

METHODS

After sensitization, a bilateral arthritis of the TMJ was induced by an intra-articular administration of ovalbumin in 12 New Zealand white rabbits aged 10 weeks. From the 13th week of age, six of the 12 rabbits received weekly intramuscular injections of MTX, and the other six animals remained without therapy. Another six animals served as controls, receiving no treatment or intra-articular injections at all. After euthanasia at the age of 22 weeks, all TMJs were retrieved en bloc. Sagittal sections were cut and stained with haematoxylin-eosin (H-E), Safranin-O for the evaluation of the Mankin score and tartrate-resistant acid phosphatase (TRAP).

RESULTS

In the arthritis group, a chronic inflammation with degeneration of the articular cartilage was visible. In the MTX group, the signs of cartilage degeneration were significantly reduced compared with the arthritis group. In contrast, the joints in the control group were inconspicuous. A correlation between the Mankin score and TRAP-positive cells could be found.

CONCLUSIONS

Systemic administration of MTX seems to have a positive effect upon the inflammatory process in the rabbit TMJ but fails to eliminate the sign of arthritis completely.

Histomorphometry in antigen-induced arthritis of the rabbit temporomandibular joint

BACKGROUND

Juvenile idiopathic arthritis (JIA) of the temporomandibular joint (TMJ) can cause severe growth disturbances of the craniomandibular system. Antigen-induced arthritis (AIA) of the rabbit TMJ is simulating the inflammatory process of the TMJ in JIA. The aim of this study was to investigate the effect of a systemic administration of the tumor necrosis factor-alpha (TNF-α) antagonist etanercept on AIA in rabbits by means of three different histological staining methods.

METHODS

After sensitization, a bilateral arthritis of the TMJ was induced and maintained by repeated intra-articular administrations of ovalbumin in 12 New Zealand white rabbits aged 10 weeks. From the 13th week of age, 6 of the 12 rabbits received weekly subcutaneous injections of etanercept, and the other 6 animals remained without therapy. Another 6 animals served as controls, receiving no treatment or intra-articular injections at all. After euthanasia at the age of 22 weeks, all TMJs were retrieved en bloc. Sagittal sections were cut and stained with hematoxylin-eosin (H-E), Safranin-O for the evaluation of the Mankin score, and tartrate-resistant acid phosphatase (TRAP).

RESULTS

In the arthritis group, a chronic inflammation with degeneration of the articular cartilage was visible. In the etanercept group, the signs of cartilage degeneration were significantly reduced but present. In contrast, the joints in the control group were inconspicuous. A strong correlation between the Mankin score and TRAP-positive cells could be found.

CONCLUSIONS

Antigen-induced arthritis causes severe damage in the TMJ of young rabbits. An improvement seems to be achievable by a systemic administration of etanercept.