Role of substance P in inflammatory arthritis

Sexual Dimorphism in the Expression of Pain Phenotype in Preclinical Models of Rheumatoid Arthritis

Rheumatoid arthritis is one of most frequent rheumatic diseases, affecting around 1% of the population worldwide. Pain impacting the quality of life for the patient with rheumatoid arthritis, is often the primary factor leading them to seek medical care. Although sex-related differences in humans and animal models of rheumatoid arthritis are described, the correlation between pain and sex in rheumatoid arthritis has only recently been directly examined. Here we review the literature and explore the mechanisms underlying the expression of the pain phenotype in females and males in preclinical models of rheumatoid arthritis.

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.

The effect of intra-articular botulinum toxin A on substance P, prostaglandin E2, and tumor necrosis factor alpha in the canine osteoarthritic joint

Background

Recently, intra-articular botulinum toxin A (IA BoNT A) has been shown to reduce joint pain in osteoarthritic dogs. Similar results have been reported in human patients with arthritis. However, the mechanism of the antinociceptive action of IA BoNT A is currently not known. The aim of this study was to explore this mechanism of action by investigating the effect of IA BoNT A on synovial fluid (SF) and serum substance P (SP), prostaglandin E₂ (PGE₂), and tumor necrosis factor alpha (TNF-α) in osteoarthritic dogs. Additionally, the aim was to compare SF SP and PGE₂ between osteoarthritic and non-osteoarthritic joints, and investigate associations between SP, PGE₂, osteoarthritic pain, and the signalment of dogs. Thirty-five dogs with chronic naturally occurring osteoarthritis and 13 non-osteoarthritic control dogs were included in the study. Osteoarthritic dogs received either IA BoNT A (n = 19) or IA placebo (n = 16). Serum and SF samples were collected and osteoarthritic pain was evaluated before (baseline) and 2 and 8 weeks after treatment. Osteoarthritic pain was assessed with force platform, Helsinki Chronic Pain Index, and joint palpation. Synovial fluid samples were obtained from control dogs after euthanasia. The change from baseline in SP and PGE₂ concentration was compared between the IA BoNT A and placebo groups. The synovial fluid SP and PGE₂ concentration was compared between osteoarthritic and control joints. Associations between SP, PGE₂, osteoarthritic pain, and the signalment of dogs were evaluated.

Results

There was no significant change from baseline in SP or PGE₂ after IA BoNT A. Synovial fluid PGE₂ was significantly higher in osteoarthritic compared to control joints. Synovial fluid PGE₂ correlated with osteoarthritic pain. No associations were found between SP or PGE₂ and the signalment of dogs. The concentration of TNF-α remained under the detection limit of the assay in all samples.

Conclusions

The results suggest that the antinociceptive effect of IA BoNT A in the joint might not be related to the inhibition of SP nor PGE₂. Synovial fluid PGE₂, but not SP, could be a marker for chronic osteoarthritis and pain in dogs.

Posterior tibial tendinopathy: what are the risk factors?

BACKGROUND

Posterior tibial tendinopathy (PTT) is the most common cause of acquired (progressive) flatfoot deformity in adults. To date, PTT research has mainly focused on management rather than on causal mechanisms. The etiology of PTT is likely to be multifactorial because both intrinsic and extrinsic risk factors have been reported. We sought to critically evaluate reported etiologic factors for PTT and consider the concept of genetic risk factors.

METHODS

A detailed review of the literature published after 1936 was undertaken using English-language medical databases.

RESULTS

No clear consensus exists as to the relative importance of the risk factors reported, and neither has any consideration been given to a possible genetic basis for PTT.

CONCLUSIONS

To date, studies have examined various intrinsic and extrinsic risk factors implicated in the etiology of PTT. The interaction of these factors with an individual's genetic background may provide valuable data and help offer a more complete risk profile for PTT. A properly constructed genetic association study to determine the genetic basis of PTT would provide a novel and alternative approach to understanding this condition.

The effects of substance p on tendinopathy are dose-dependent: an in vitro and in vivo model study

OBJECTIVES

Substance P (SP) is known to be involved in neuropathic pain, chronic inflammation, and tendinopathy. The present study evaluated the effects of different doses of SP on tendon-derived stem cells (TDSCs) in vitro and tendons in vivo.

METHODS

For the in vitro study, TDSCs cultured in growth medium with different concentrations of SP (negative control, 0.1 nM, and 1.0 nM). The effects of SP on TDSCs were examined with respect to their ability to proliferate and differentiate. For the in vivo study, we injected different doses of SP (saline control, 0.5 nmol, and 5.0 nmol) into rat patella tendons to investigate the effects of SP on tendons.

RESULTS

Low and high doses SP significantly enhanced the proliferation ability of TDSCs. Low-dose of SP induced the expression of tenocyte-related genes; however, high-dose of SP induced the expression of non-tenocyte genes, which was evident by the high expression of PPARγ and collagen type II. In the in vivo study, only high-doses of SP (5.0 nmol) induced the tendinosis-like changes in the patella tendon injection model. Low doses of SP (0.5 nmol) enhanced the tenogenesis compared with saline injection and the high-dose SP group.

CONCLUSIONS

SP enhances the proliferation of TDSCs in vitro and the effects of SP on tendinopathy are dose-dependent in vivo.

Efficacy of intraarticular botulinum toxin A and intraarticular hyaluronate plus rehabilitation exercise in patients with unilateral ankle osteoarthritis: a randomized controlled trial

Background

There was an increasing requirement for novel treatments of osteoarthritis (OA). The aim was to compare the efficacy of intraarticular Botulinum toxin type A (BoNT-A) and intraarticular hyaluronate plus rehabilitation exercise in patients with ankle OA.

Methods

This was a prospective, randomized, assessor-blinded study with a 6-month follow-up period, conducted in the outpatient rehabilitation department at a university-affiliated tertiary care medical center. Seventy-five patients with symptomatic ankle OA (Kellgren-Lawrence grade 2) were randomized to receive either a single 100-unit BoNT-A injection into the target ankle (n = 38) or a single hyaluronate injection plus 12 sessions of rehabilitation exercise (30 minutes/day, 3 times/week for 4 weeks) (n = 37). The primary outcome measure was the Ankle Osteoarthritis Scale (AOS). Secondary outcome measures included American Orthopedic Foot and Ankle Society (AOFAS) Ankle/Hindfoot Score, visual analog scale (VAS) for ankle pain, single leg stance test (SLS), Timed “Up-and-Go” test (TUG), consumption of rescue analgesics and global patient satisfaction.

Results

There were no significant between-group differences in total AOS scores, pain subscale and disability subscale scores (adjusted mean difference AMD = -0.2, 95% CI = (-0.5, 0.2), p = 0.39; AMD = -0.1, 95% CI = (-0.5, 0.3), p = 0.57; AMD = -0.2, 95% CI = (-0.6, 0.2), p = 0.36). The 2 groups showed no significant differences in AOFAS, VAS, SLS, TUG scores and consumption of rescue analgesics at each follow-up visit, except that the hyaluronate group improved more in SLS than the BoNT-A group at 1-month follow-up. Patients’ satisfaction rate was high, with no serious adverse events. There was no difference in adverse events between the two groups (p = 1.00).

Conclusions

Treatment with intraarticular BoNT-A or hyaluronate injection plus rehabilitation exercise was associated with improvements in pain, physical function and balance in patients with ankle OA. These effects were rapid at 2 weeks and might last for at least 6 months. There was no difference in effectiveness between the two interventions.

Trial registration

The trial was registered at clinical trials.gov (Registry number NCT01760577).

Pore-forming compounds as signal transduction elements for highly sensitive biosensing

Pore-forming compounds are attracting much attention due to the signal transduction ability for the development of highly sensitive biosensing. In this review, we describe an overview of the recent advances made by our group in the design of molecular sensing interfaces of spherical and planar lipid bilayers and natural bilayers. The potential uses of pore-forming compounds, such as gramicidin and MCM-41, in lipid bilayers and natural glutamate receptor channels in biomembrane are presented.

Design and Construction of Thermally Combined Microcurrent Electrical Therapy Device as Preliminary Study for Rheumatoid Arthritis Treatment

Rheumatoid Arthritis (RA) is a chronic inflammatory disease that destructs the cartilage within joints. Even though RA cannot be cured, its progress can be slowed and its symptoms can be managed by applying microcurrent and thermal therapy to enhance the healing process of the joints. This research aims to combine two different therapeutic modalities: Microcurrent Electrical Therapy (MET) and thermal therapy, which will be called as Thermally combined Microcurrent Electrical Therapy (T-MET) device. For MET, the resulted output was square wave with fix 50% duty cycle, adjustable frequency (0.31 – 100Hz), and adjustable current amplitude (36 - 466µA). For thermal therapy, two different modes were provided: heating mode (up to 40°C) and cooling mode (up to 15°C). The test was done three times. It took 30 minutes and 105.8 minutes to reach the upper and lower limit temperature respectively. T-MET device had been designed and constructed. However, clinical trials to RA patient needs to be further investigated.

Tendons--time to revisit inflammation

It is currently widely accepted among clinicians that chronic tendinopathy is caused by a degenerative process devoid of inflammation. Current treatment strategies are focused on physical treatments, peritendinous or intratendinous injections of blood or blood products and interruption of painful stimuli. Results have been at best, moderately good and at worst a failure. The evidence for non-infammatory degenerative processes alone as the cause of tendinopathy is surprisingly weak. There is convincing evidence that the inflammatory response is a key component of chronic tendinopathy. Newer anti-inflammatory modalities may provide alternative potential opportunities in treating chronic tendinopathies and should be explored further.

Current concepts in the management of tendon disorders

Primary disorders of tendons are common and constitute a high proportion of referrals to rheumatologists. Certain tendons are particularly vulnerable to degenerative pathology; these include the Achilles, patella, elements of the rotator cuff, forearm extensors, biceps brachi and tibialis posterior tendons. Disorders of these tendons are often chronic and can be difficult to manage successfully in the long term. Significant advances have been made in understanding the pathophysiology of these conditions. Histopathological evidence, together with advances in imaging techniques, has made us more appreciative of the degenerative (rather that inflammatory) nature of these conditions. Additionally the presence of neovascularization is now well-recognized in long-standing tendinopathy. We review the mechanical, vascular and developing neural theories that attempt to explain the aetiology of degenerative tendinopathy. We also explore theories of why specific tendons (such as the Achilles and supraspinatus tendons) are particularly prone to degenerative pathology. Traditionally, treatments have placed a heavy emphasis on anti-inflammatory strategies, which are often inappropriate. Recently, however, significant advances in the practical management of tendon disorders have been made. In particular the advent of 'eccentric loading' training programmes has revolutionized the treatment of Achilles tendinopathy in some patients. This concept is currently being extended to include other commonly injured tendons. Other current treatments are reviewed, as are potential future treatments.

Combined effect of bradykinin B2 and neurokinin-1 receptor activation on endothelial cell proliferation in acute synovitis

During acute synovitis, early angiogenesis may enhance inflammation by facilitating edema formation and cellular infiltration. We have investigated the in vivo modulation by bradykinin of neurally enhanced early angiogenesis in rat models of knee synovitis. The increased endothelial cell proliferation that was observed 24 h after intra-articular injection of substance P (10 nmols) was completely blocked by either NK1 or B2 receptor antagonists (SR140333 or FR172357, respectively). In mild synovitis induced by 0.03% Carrageenan, but not in naïve animals, injection of bradykinin (100 nmols) increased endothelial cell proliferation. In moderate synovitis induced by 3% kaolin and 3% carrageenan, the combined blockade of both NK1 and B2 receptors inhibited 64% of the synovitis-enhanced endothelial cell proliferation. Synovitis-enhanced endothelial cell proliferation was also inhibited by the B2 receptor antagonist alone (27%) but not by the NK1 receptor antagonist alone. B1 receptor agonist (des-Arg9-bradykinin) and antagonist (SR240612A) did not significantly modulate endothelial cell proliferation. B2 receptor mRNA was constitutively expressed in both mild and moderate inflammation, whereas B1 mRNA production was induced in the moderate inflammation model. These findings demonstrate that substance P and bradykinin can act on NK1 and B2 receptors, respectively, to promote endothelial cell proliferation in acute synovitis.

Enhancement of angiogenesis by endogenous substance P release and neurokinin-1 receptors during neurogenic inflammation

Early angiogenesis is a key step in the transition from acute to persistent inflammation. The nervous system has long been known to play a role in inflammation, in part through the release of substance P from peripheral nerve terminals (neurogenic inflammation). Application of substance P can stimulate vessel growth in a variety of angiogenesis assays, although it was previously not known whether endogenous substance P released from sensory nerves could modulate angiogenesis. We hypothesized that endogenous substance P can initiate angiogenesis during acute neurogenic inflammation. Here we show that 10 nmol of substance P can stimulate angiogenesis within the rat knee synovium, as shown by increased endothelial cell proliferation index [PCNA index, 19% (95% confidence interval (CI), 17 to 20%)] compared with saline injected knees [6% (95% CI, 4% to 8%), p < 0.05]. Moreover, this was prevented by coadministration of an antagonist of the neurokinin-1 (NK1) subtype of neurokinin receptor SR140333 (nolpitantium), 1 micro mol [8% (95% CI, 5% to 11%)]. Capsaicin 0.5%, which stimulates release of endogenous substance P from sensory nerves, was also found to enhance synovial angiogenesis, [PCNA index 17% (95% CI, 14% to 19%)] compared with saline injected control knees [2% (95% CI, 1% to 3%), p < 0.05], and this also was inhibited by 1 micro mol of SR140333 [11% (95% CI, 8 to 16%)]. Inhibition of capsaicin-enhanced angiogenesis was incomplete, and this may indicate a contribution of other neuropeptides, in addition to substance P-NK1 receptor interactions, in capsaicin-enhanced angiogenesis. NK1 receptor antagonists could have therapeutic potential in conditions where neurogenic angiogenesis contributes to disease.

Substance P receptor (NK1) gene expression in synovial tissue in rheumatoid arthritis and osteoarthritis

The distribution of messenger RNA coding for substance P receptor (NK1) in rheumatoid synovia and the relationship between signal intensity of NK1 mRNA and clinical parameters of disease activity were investigated. The synovia from 10 patients with rheumatoid arthritis (RA) and 7 patients with osteoarthritis was investigated by in situ hybridization histochemistry. In rheumatoid synovia, strong hybridization signal of NK1 mRNA was detected in 80% of the cells in both the lining layer and the interstitial layer. Moreover, the signal intensities of NK1 mRNA positively correlated with serum C-reactive protein levels and radiographic grade of joint destruction. These results provide histochemical evidence that rheumatoid synoviocytes strongly express NK1 gene, and the positive relation of the signal intensity of NK1 mRNA with CRP and radiographic severity suggests that the facilitation of NK1 gene expression in rheumatoid synovium relate the disease progression of RA.

Direct adenovirus-mediated gene transfer of interleukin 1 and tumor necrosis factor alpha soluble receptors to rabbit knees with experimental arthritis has local and distal anti-arthritic effects

Adenoviral vectors were used to deliver genes encoding a soluble interleukin 1 (IL-1)-type I receptor-IgG fusion protein and/or a soluble type I tumor necrosis factor alpha (TNFalpha) receptor-IgG fusion protein directly to the knees of rabbits with antigen-induced arthritis. When tested individually, knees receiving the soluble IL-1 receptor had significantly reduced cartilage matrix degradation and white blood cell infiltration into the joint space. Delivery of the soluble TNFalpha receptor was less effective, having only a moderate effect on white blood cell infiltration and no effect on cartilage breakdown. When both soluble receptors were used together, there was a greater inhibition of white blood cell infiltration and cartilage breakdown with a considerable reduction of synovitis. Interestingly, anti-arthritic effects were also seen in contralateral control knees receiving only a marker gene, suggesting that sustained local inhibition of disease activity in one joint may confer an anti-arthritic effect on other joints. These results suggest that local intra-articular gene transfer could be used to treat systemic polyarticular arthritides.

Neurogenic inflammation in cholecystitis

Neurogenic inflammation implies stimulation of nerves with resultant inflammation in tissue surrounding the nerve terminals. We hypothesized that neurogenic inflammation has a role in cholecystitis. Capsaicin (stimulant of afferent, nociceptive neurons), 6-hydroxydopamine (stimulates release of peptides from sympathetic nerve terminals), bradykinin, lipopolysaccharide, and saline were instilled into guinea pig gallbladders for 24 hr (N = 5 in each group). In parallel, test agents were instilled with 1% Iidocaine. Water transport across gallbladder mucosa, myeloperoxidase and interluekin-1 release from gallbladder tissue, and prostaglandin E2 in luminal fluid were measured. Capsaicin caused water secretion and significant release of myeloperoxidase, interleukin-1, and prostaglandin-E2, effects that were blocked by Iidocaine. 6-Hydroxydopamine did not affect water transport or prostaglandin E2, but did cause myeloperoxidase and interleukin-1 release. Bradykinin- and lipopolysaccharide-induced inflammation were partially inhibited by lidocaine. Taken together, these results suggest that neurogenic inflammation has a role in the pathophysiology of cholecystitis.

Endogenous substance P mediates cold water stress-induced increase in interleukin-6 secretion from peritoneal macrophages

Previous studies from this laboratory had shown that exposure of mice to cold water stress leads to an increase in the secretion of interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF alpha) from their peritoneal macrophages. We now report that the secretion of IL-6 from peritoneal macrophages is also increased after cold water stress and that the peptide substance P (SP) participates in this stress-induced response. The stress paradigm involved subjecting male C57BL/6J mice to 5 min swim tests in 10 +/- 2 degrees C water twice daily for 4 d. Cold water stress augments the lipopolysaccharide-induced IL-6 secretion from peritoneal macrophages, elevates immunoreactive SP (iSP) in the peritoneal wash fluid, and reduces iSP in certain peritoneum-containing tissues or organs (i.e., diaphragm, abdominal wall, ileum, and rectum). The 10 d stress time studies indicate that increased IL-6 secretion is positively related to elevated iSP in the peritoneal wash fluid and inversely related to reduced iSP in certain peritoneum-containing tissues. Pretreatment with capsaicin, which depletes SP in the sensory nerve endings, eliminates stress-control differences in the peritoneal wash fluid and in certain peritoneal tissues. Moreover, RP67,580, a specific SP antagonist, eliminates the cold water stress-induced augmentation of IL-6 secretion from peritoneal macrophages. These results suggest that cold water stress promotes the release of SP from peritoneal tissues into the peritoneal cavity, where it participates in the cold water stress-induced macrophage functional alterations.

Endogenous substance P mediates cold water stress-induced increase in interleukin-6 secretion from peritoneal macrophages

Previous studies from this laboratory had shown that exposure of mice to cold water stress leads to an increase in the secretion of interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF alpha) from their peritoneal macrophages. We now report that the secretion of IL-6 from peritoneal macrophages is also increased after cold water stress and that the peptide substance P (SP) participates in this stress-induced response. The stress paradigm involved subjecting male C57BL/6J mice to 5 min swim tests in 10 +/- 2 degrees C water twice daily for 4 d. Cold water stress augments the lipopolysaccharide-induced IL-6 secretion from peritoneal macrophages, elevates immunoreactive SP (iSP) in the peritoneal wash fluid, and reduces iSP in certain peritoneum-containing tissues or organs (i.e., diaphragm, abdominal wall, ileum, and rectum). The 10 d stress time studies indicate that increased IL-6 secretion is positively related to elevated iSP in the peritoneal wash fluid and inversely related to reduced iSP in certain peritoneum-containing tissues. Pretreatment with capsaicin, which depletes SP in the sensory nerve endings, eliminates stress-control differences in the peritoneal wash fluid and in certain peritoneal tissues. Moreover, RP67,580, a specific SP antagonist, eliminates the cold water stress-induced augmentation of IL-6 secretion from peritoneal macrophages. These results suggest that cold water stress promotes the release of SP from peritoneal tissues into the peritoneal cavity, where it participates in the cold water stress-induced macrophage functional alterations.

Might patients with HLA-B27 related diseases benefit from antiandrogenic treatment?

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Asymmetric rheumatoid vasculitis in a hemiplegic patient

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NK1 receptors mediate tachykinin-induced plasma extravasation in the rat knee joint

The tachykinin receptor type that mediates tachykinin-induced plasma extravasation in the rat knee joint was identified by using selective antagonists as well as natural or synthetic agonists. Substance P (SP) and neurokinin (NK) A induced plasma extravasation with almost the same potency and the maximum response was obtained at 5 nmol/knee. NKB was about ten times less potent than SP or NKA. The NK1 selective agonist, [Sar9, Met(O2)11]-SP, was about ten times more potent than SP, and the NK2 selective agonist, [Nle10]-NKA4-10, was about fifty times less potent than NK1 agonist. The NK3 agonist, Senktide, was totally ineffective at 0.5-50 nmol/knee. All responses induced by SP (5 nmol/knee), NKA (5 nmol/knee), NKB (50 nmol/knee), NK1 agonist (0.5 nmol/knee) or NK2 agonist (25 nmol/knee) were significantly and profoundly inhibited by the NK1 selective antagonist, RP67580, but not by the NK2 selective antagonist, SR48968. Taken together, we conclude that tachykinin-induced plasma extravasation in the rat knee joint is mediated via NK1 receptors.