Antiarthritic Effects of Relaxin, in Combination with Estrogen, in Rat Adjuvant-Induced Arthritis

Potential Molecular Mechanisms of Plantain in the Treatment of Gout and Hyperuricemia Based on Network Pharmacology

BACKGROUND

The incidence of gout and hyperuricemia is increasing year by year in the world. Plantain is a traditional natural medicine commonly used in the treatment of gout and hyperuricemia, but the molecular mechanism of its active compounds is still unclear. Based on network pharmacology, this article predicts the targets and pathways of effective components of plantain for gout and hyperuricemia and provides effective reference for clinical medication.

METHOD

Traditional Chinese medicine systems pharmacology database and analysis platform (TCMSP) and SymMap databases were used to screen out the active compounds and their targets in plantain. GeneCards, Therapeutic Target Database (TTD), and Online Mendelian Inheritance in Man (OMIM) databases were used to find the targets corresponding to gout and hyperuricemia. Venn diagram was used to obtain the intersection targets of plantain and diseases. The interaction network of the plantain active compounds-targets-pathways-diseases was constructed by using Cytoscape 3.7.2 software. Finally, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were carried out.

RESULT

Seven active compounds were identified by network pharmacological analysis, including dinatin, baicalein, baicalin, sitosterol, 6-OH-luteolin, stigmasterol, and luteolin. Plantain plays a role in gout and hyperuricemia diseases by regulating various biological processes, cellular components, and molecular functions. The core targets of plantain for treating gout are MAPK1, RELA, TNF, NFKBIA, and IFNG, and the key pathways are pathways in cancer, hypoxia-inducible factor-1 (HIF-1) signaling pathway, interleukin (IL)-17 signaling pathway, Chagas disease (American trypanosomiasis), and relaxin signaling pathway. The core targets of plantain for hyperuricemia are RELA, MAPK1, NFKBIA, CASP3, CASP8, and TNF, and the main pathways are pathways in cancer, apoptosis, hepatitis B, IL-17 signaling pathway, and toxoplasmosis.

CONCLUSION

This study explored the related targets and mechanisms of plantain for the treatment of gout and hyperuricemia from the perspective of network pharmacological analysis, reflecting the characteristics of multiple components, multiple targets, and multiple pathways, and it provides a good theoretical basis for the clinical application of plantain.

Synovial interlukin-6 affects apoptosis induction via nuclear factor kappa-B and fractalkine pathway during adjuvant arthritis

Background: Apoptosis disruptions play substantial roles in pathogenesis of arthritis and its symptoms. Cytokines and their intracellular signaling have pivotal roles in arthritis pathophysiology. This study aimed to investigate the relationship between synovial Interleukin-6 (IL-6), nuclear factor kappa-B (NF-ĸB), and fractalkine (FKN) in the changes of edema and apoptosis during adjuvantinduced knee arthritis. Methods: A total of 240 male Wistar rats were divided into different groups. Arthritis was evoked and the knee edema changes were evaluated by Vernier caliper. Synovial IL-6 was assayed by rat standard ELISA kit. Levels of NF-ĸB, fractalkine, and apoptotic indicators in the synovium were evaluated by Western blot method. Results were expressed as Mean± SEM. To analyze within-group variations, repeated measures ANOVA, followed by post hoc Tukey's test was used (SPSS, 16). Independent samples t test was used to designate significant differences in knee diameter, synovial level of IL-6, apoptotic markers, NF-ĸB, and FKN between groups. Significance level was set at P≤ 0.05. Results: The injection of Complete Freund's Adjuvant (CFA) caused intense knee edema (P< 0.001), which was reduced by implementing anti-IL-6 (P< 0.001), anti-FKN (P< 0.001), Inh-NF-ĸB (P< 0.001), and anti-FKN+ Inh NF-kB (P< 0.001). The results indicated elevated levels of apoptotic markers during the acute phase (P = 0.010), along with an increase in IL-6 (P< 0.001), NF-ĸB (P< 0.001), and FKN (P= 0.030). Although IL-6 (P< 0.001), NF-ĸB (P= 0.001), and FKN (P= 0.007) levels elevation continued during the chronic phase, the apoptosis markers decreased in this phase (P= 0.050). The findings revealed that Anti-IL-6 treatment during different phases of the study could change the synovial NF-ĸB and FKN. Conclusion: It seems that time-dependent variations in apoptotic markers level may be involved in pathogenesis of adjuvant-induced knee arthritis. In conclusion, synovial IL-6 through NF-ĸB- FKN pathway can play an important role in this process.

The Impact of Synovial NF-κB Activation on Apoptosis Pattern Change During Adjuvant-induced Inflammation

Introduction:

Apoptosis dysregulation plays a substantial role in the pathophysiology of chronic inflammation and its related symptoms such as edema. Regulation of NF-κB activation is involved in apoptosis pattern change. The current study aimed at verifying the effects of local inflammation on edema and changes in apoptotic markers, and investigating the possible role of NF-κB in apoptosis pattern change during different stages of complete Freund’s adjuvant (CFA)-induced knee arthritis in rats.

Methods:

A total of 96 male Wistar rats were divided into different experimental groups. Arthritis was evoked into the right knee articular joint. Changes made in knee edema were assessed by caliper on the days 0, 7, 14, and 21 of the study. Synovial NF-κB and levels of apoptotic markers were evaluated during different stages of the study using Western blot technique.

Results:

CFA injection caused intense edema during the whole study period. Synovial NF-κB level increased during the whole study period. The level of apoptotic markers increased during the acute phase of study. But during chronic phase, the apoptosis level decreased. Inh-NF-κB administration increased synovial apoptosis during the whole study period.

Conclusion:

It seems that apoptosis pattern change plays an important role in the progression and modulation of CFA-induced inflammation and its related symptoms. Also, it can be concluded that synovial NF-κB had a crucial role in synovial apoptosis change during the study period.

Relaxin Level in Patients With Atrial Fibrillation and Association with Heart Failure Occurrence: A STROBE Compliant Article

Atrial fibrillation (AF) is the most common arrhythmia requiring medical treatment and has been associated with enhanced atrial fibrosis and heart failure (HF). Relaxin (RLX), an antifibrosis and antiinflammatory peptide hormone, may be used to evaluate atrial fibrosis and is associated with HF occurrence in AF. We aimed to clarify the clinical significance of RLX level in patients with AF.We measured circulating levels of RLX and other fibrosis-related factors in 311 patients with sinus rhythm (SR; n = 116) or AF (n = 195). All discharged AF patients were followed up for the occurrence of HF for a mean of 6 months.Circulating levels of RLX were significantly different in patients with AF as compared with SR (P < 0.001), and in the subgroup analysis of AF. RLX level was correlated with left atrial diameter (LAD; R = 0.358, P < 0.001). Among followed up AF patients, on Kaplan-Meier curve analysis, patients with the third RLX tertile (T3) had a significantly higher HF rate than those with the 1st tertile (T1) (P = 0.002) and the cut-off value was 294.8 ng/L (area under the ROC curve [AUC] = 0.723). On multivariable analysis, HF occurrence with AF was associated with increased tertile of serum RLX level (odds ratio [OR] 2.659; confidence interval [95% CI] 1.434-4.930; P = 0.002).RLX is associated with fibrosis-related biomarkers and significantly elevated in AF. RLX was related to the HF occurrence in patients with AF.

Long-Term Treatment by Vitamin B1 and Reduction of Serum Proinflammatory Cytokines, Hyperalgesia, and Paw Edema in Adjuvant-Induced Arthritis

INTRODUCTION

Immune system is involved in the etiology and pathophysiology of inflammation and vitamins are important sources of substances inducing nonspecific immunomodulatory effects. Given the proinflammatory role of cytokines in the inflammation and pain induction, this study aimed to assess the effects of long-term administration of vitamin B₁ on the proinflammatory cytokines, edema, and hyperalgesia during the acute and chronic phases of adjuvant-induced arthritis.

METHODS

On the first day of study, inflammation was induced by intraplantar injection of complete Freund's adjuvant (CFA) in the hindpaws of rats. Vitamin B₁ at doses of 100, 150, and 200 mg/kg was administrated intraperitoneally during 21 days of the study. Antinociceptive and anti-inflammatory effects of vitamin B₁ were also compared to indomethacin (5 mg/kg). Inflammatory symptoms such as thermal hyperalgesia and paw edema were measured by radiant heat and plethysmometer, respectively. Serum TNF-α and IL-1β levels were checked by rat standard enzyme-linked immune sorbent assay (ELISA) specific kits.

RESULTS

The results indicated that vitamin B₁(150 and 200 mg/kg) attenuated the paw edema, thermal hyperalgesia, and serum levels of TNF-α and IL-1β during both phases of CFA-induced inflammation in a dose-dependent manner. Effective dose of vitamin B₁(150 mg/kg) reduced inflammatory symptoms and serum levels of TNF-α and IL-1β compare to indomethacin during the chronic phase of inflammation.

CONCLUSION

Anti-inflammatory and antihyperalgesic effects of vitamin B1 during CFA-induced arthritis, more specifically after chronic vitamin B₁ administration, suggest its therapeutic property for inflammation.

Estradiol ameliorates arthritis and protects against systemic bone loss in Staphylococcus aureus infection in mice

INTRODUCTION

Staphylococcus aureus is a common cause of bacterial arthritis, which is associated with progressive bone loss in affected joints. We recently showed that S. aureus infection also induces a significant systemic bone loss in mice. This study was performed to assess the effect of estradiol treatment on the clinical course and outcome of S. aureus arthritis and on infection-induced bone loss in experimental S. aureus infection.

METHODS

Mice were ovariectomized, treated with estradiol or placebo, and S. aureus infection was established by intravenous inoculation of bacteria.

RESULTS

Estradiol treatment was found to decrease significantly the frequency and clinical severity of S. aureus arthritis, a finding that was accompanied with significantly higher serum levels of interleukin-10 in estradiol-treated mice. Estradiol was also highly protective against S. aureus-induced systemic trabecular, and cortical bone loss. Lack of endogenous estrogens and S. aureus infection had additive effects on trabecular bone loss. The S. aureus-infected, ovariectomized mice lost as much as 76% of their trabecular bone mass.

CONCLUSIONS

Treatment with estradiol ameliorates S. aureus arthritis and is protective against infection-induced systemic bone loss in experimental S. aureus infection.

Differential effects of chlorogenic acid on various immunological parameters relevant to rheumatoid arthritis

Despite chlorogenic acid (CGA) being widely present in nature, particularly in the human diet, there is very little information regarding its pharmacological activities. The present investigation was carried out to investigate the antiarthritic activities of this compound in adjuvant induced-arthritis in male Wistar rats, and to explore the underlying mechanisms of actions in view of immunological responses. We observed that CGA effectively controlled the total (CD3) and differentiated (CD4 and CD8) T cells count at the dose of 40 mg/kg. We also assessed the effect on co-stimulatory molecules (CD28, CD80/86) and found that CGA efficiently suppressed CD80/86 but failed to bring any changes in the CD28 count, whereas ibuprofen (standard drug) resulted in highly significant inhibition of both. We next examined the effect on CD4⁺ T cells specific Th1/Th2 cytokines by flow cytometry and observed that CGA suppressed the Th1 cytokines in a highly significant manner but elevated Th2 cytokines with dose dependence. Results of the present investigation suggest that CGA is a potent antiarthritic agent.

Effects of relaxin and estrogens on bone remodeling markers, receptor activator of NF-kB ligand (RANKL) and osteoprotegerin (OPG), in rat adjuvant-induced arthritis

Rheumatoid arthritis (RA) is characterized by joint inflammation and bone destruction. The receptor activator of nuclear factor-kappa B ligand (RANKL)-osteoprotegerin (OPG) system is important for maintaining the balance between bone resorption and formation. Both serum RANKL/OPG protein and synovial tissue RANKL/OPG mRNA ratios are elevated in patients with RA. Studies indicate that hormones of pregnancy, estrogens and relaxin, administered in combination, reduce circulating (TNF)-α and joint inflammation in a rat adjuvant-induced arthritis (AIA) model of RA. The purpose of this study was to investigate whether relaxin (RLX), alone or in combination with estrogens, regulates the bone remodeling markers RANKL and OPG in vivo and in vitro. Results show that in AIA rats, treatment with relaxin, estradiol valerate (EV) or EV in combination with relaxin had no effect on circulating RANKL. However, EV increased systemic OPG and combined treatment with EV and relaxin further increased circulating OPG in comparison to EV alone. Importantly, the RANKL/OPG protein ratio was lower in rats treated with EV or EV+RLX when compared to arthritic controls. Relaxin in combination with EV decreased local RANKL transcripts, increased OPG mRNA and decreased the RANKL/OPG mRNA ratio in joints of arthritic rats when compared to controls. RLX family peptide receptor 1 (RXFP1) gene expression in joints of AIA rats increased in response to EV and EV+RLX. In parathyroid hormone-pretreated murine UMR 106-01 osteoblast cells, 17-β-estradiol (E) and E+RLX increased RXFP1 transcripts, while RLX reduced RANKL mRNA and protein expression. However, in vitamin D-treated primary rat osteoblast cells E+RLX increased OPG protein and reduced the RANKL/OPG protein ratio. These results suggest that modulation of the RANKL-OPG system by estrogens and RLX may contribute to their antiarthritic effects on bone during pregnancy.

Relaxin: review of biology and potential role in treating heart failure

Relaxin is a naturally occurring human peptide initially identified as a reproductive hormone. More recently, relaxin has been shown to play a key role in the maternal hemodynamic and renal adjustments that accommodate pregnancy. An understanding of these physiologic effects has led to the evaluation of relaxin as a pharmacologic agent for the treatment of patients with acute heart failure. Preliminary results have been encouraging. In addition, the other known biologic properties of relaxin, including anti-inflammatory effects, extracellular matrix remodeling effects, and angiogenic and anti-ischemic effects, all may play a role in potential benefits of relaxin therapy. Ongoing, large-scale clinical testing will provide additional insights into the potential role of relaxin in the treatment of heart failure.

Gender and sex hormones in multiple sclerosis pathology and therapy

Several lines of evidence indicate that gender affects the susceptibility and course of multiple sclerosis (MS) with a higher disease prevalence and overall better prognosis in women than men. This sex dimorphism may be explained by sex chromosome effects and effects of sex steroid hormones on the immune system, blood brain barrier or parenchymal central nervous system (CNS) cells. The well known improvement in disease during late pregnancy has also been linked to hormonal changes and has stimulated recent clinical studies to determine the efficacy of and tolerance to sex steroid therapeutic approaches. Both clinical and experimental studies indicate that sex steroid supplementation may be beneficial for MS. This could be related to anti-inflammatory actions on the immune system or CNS and to direct neuroprotective properties. Here, clinical and experimental data are reviewed with respect to the effects of sex hormones or gender in the pathology or therapy of MS or its rodent disease models. The different cellular targets as well as some molecular mechanisms likely involved are discussed.

Modulation of pain by estrogens

It has become increasingly apparent that women suffer a disproportionate amount of pain during their lifetime compared to men. Over the past 15 years, a growing number of studies have suggested a variety of causes for this sex difference, from cellular to psychosocial levels of analysis. From a biological perspective, sexual differentiation of pain appears to occur similarly to sexual differentiation of other phenomena: it results in large part from organizational and activational effects of gonadal steroid hormones. The focus of this review is the activational effects of a single group of ovarian hormones, the estrogens, on pain in humans and animals. The effects of estrogens (estradiol being the most commonly examined) on experimentally induced acute pain vs. clinical pain are summarized. For clinical pain, the review is limited to a few syndromes for which there is considerable evidence for estrogenic involvement: migraine, temporomandibular disorder (TMD) and arthritis. Because estrogens can modulate the function of the nervous, immune, skeletal, and cardiovascular systems, estrogenic modulation of pain is an exceedingly complex, multi-faceted phenomenon, with estrogens producing both pro- and antinociceptive effects that depend on the extent to which each of these systems of the body is involved in a particular type of pain. Forging a more complete understanding of the myriad ways that estrogens can ameliorate vs. facilitate pain will enable us to better prevent and treat pain in both women and men.