Targeted-Neuroinflammation Mitigation Using Inflammasome-Inhibiting Nanoligomers is Therapeutic in an Experimental Autoimmune Encephalomyelitis Mouse Model

Multiple sclerosis (MS) is a debilitating autoimmune disease that impacts millions of patients worldwide, disproportionately impacting women (4:1), and often presenting at highly productive stages of life. This disease affects the spinal cord and brain and is characterized by severe neuroinflammation, demyelination, and subsequent neuronal damage, resulting in symptoms like loss of mobility. While untargeted and pan-immunosuppressive therapies have proven to be disease-modifying and manage (or prolong the time between) symptoms in many patients, a significant fraction are unable to achieve remission. Recent work has suggested that targeted neuroinflammation mitigation through selective inflammasome inhibition can offer relief to patients while preserving key components of immune function. Here, we show a screening of potential therapeutic targets using inflammasome-inhibiting Nanoligomers (NF-κB1, TNFR1, TNF-α, IL-6) that meet or far-exceed commercially available small-molecule counterparts like ruxolitinib, MCC950, and deucravacitinib. Using the human brain organoid model, top Nanoligomer combinations (NF-κB1 + TNFR1: NI111, and NF-κB1 + NLRP3: NI112) were shown to significantly reduce neuroinflammation without any observable negative impact on organoid function. Further testing of these top Nanoligomer combinations in an aggressive experimental autoimmune encephalomyelitis (EAE) mouse model for MS using intraperitoneal (IP) injections showed that NF-κB1 and NLRP3 targeting Nanoligomer combination NI112 rescues mice without observable loss of mobility or disability, minimal inflammation in brain and spinal cord histology, and minimal to no immune cell infiltration of the spinal cord and no demyelination, similar to or at par with mice that received no EAE injections (negative control). Mice receiving NI111 (NF-κB1 + TNFR1) also showed reduced neuroinflammation compared to saline (sham)-treated EAE mice and at par/similar to other inflammasome-inhibiting small molecule treatments, although it was significantly higher than NI112 leading to subsequent worsening clinical outcomes. Furthermore, treatment with an oral formulation of NI112 at lower doses showed a significant reduction in EAE severity, albeit with higher variance owing to administration and formulation/fill-and-finish variability. Overall, these results point to the potential of further development and testing of these inflammasome-targeting Nanoliogmers as an effective neuroinflammation treatment for multiple neurodegenerative diseases and potentially benefit several patients suffering from such debilitating autoimmune diseases like MS.

The First Case of a Korean Patient with a Mutation-Confirmed Tumor Necrosis Factor Receptor-Associated Periodic Syndrome

Tumor necrosis factor receptor-associated periodic syndrome (TRAPS, OMIM: #142680) is a rare autoinflammatory disease (AID) with recurrent febrile episodes. To our knowledge, we report herein the first case of a patient with TRAPS in South Korea whose symptoms included fever, arthralgia, abdominal pain, rash, myalgia, cough, and lymphadenopathy. A pathogenic de novo mutation, c.175T>C (p.Cys59Arg), in the tumor necrosis factor receptor superfamily member 1A (TNFRSF1A) gene, was confirmed by gene sequencing. The patient has been with tocilizumab (an interleukin-6 inhibitor); tocilizumab administration every other week has completely alleviated the patient's symptoms. Our report further expands the clinical spectrum of patients with TRAPS and reaffirms the use of tocilizumab as a viable alternative treatment option for those patients who are unsatisfactorily responsive to other commonly used biologics, such as canakinumab, anakinra, infliximab, and etanercept. Furthermore, our report may aid in increasing awareness about the existence of mutation-confirmed TRAPS in South Korea in addition to emphasizing the importance of actively pursuing genetic testing to correctly diagnose rare AID.

Tetramethylpyrazine inhibits the inflammatory response by downregulating the TNFR1/IκB-α/NF-κB p65 pathway after spinal cord injury

Previous studies have demonstrated that tetramethylpyrazine (TMP) can enhance the recovery of motor function in spinal cord injury (SCI) rats. However, the underlying mechanism involved in this therapeutic effect remains to be elucidated. We conducted RNA sequencing with a network pharmacology strategy to predict the targets and mechanism of TMP for SCI. The modified Allen's weight-drop method was used to construct an SCI rat model. The results indicated that the nuclear transfer factor-κB (NF-κB) pathway was identified through the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and an inflammatory response was identified through the Gene Ontology (GO) enrichment analysis. Tumor necrosis factor (TNF) was identified as a crucial target. Western blotting revealed that TMP decreased the protein expression of TNF superfamily receptor 1 (TNFR1), inhibitor κB-α (IκB-α), and NF-κB p65 in spinal cord tissues. Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) demonstrated that TMP inhibited TNF-α, interleukin-1β (IL-1β), reactive oxygen species (ROS), and malondialdehyde (MDA) expression and enhanced superoxide dismutase (SOD) expression. Histopathological observation and behavior assessments showed that TMP improved morphology and motor function. In conclusion, TMP inhibits inflammatory response and oxidative stress, thereby exerting a neuroprotective effect that may be related to the regulation of the TNFR1/IκB-α/NF-κB p65 signaling pathway.

TNF-R1 Cellular Nanovesicles Loaded on the Thermosensitive F-127 Hydrogel Enhance the Repair of Scalded Skin

Excessive inflammatory response after severe scalding is an important cause of delayed wound healing and is even life-threatening. Tumor necrosis factor α (TNF-α) is a key pro-inflammatory factor of skin trauma. Interacting with tumor necrosis factor receptor 1 (TNF-R1), TNF-α causes excessive inflammation and poor prognosis by activating NF-κB pathway. Antagonizing high levels of TNF-α is one of the therapeutic approaches for diseases associated with the overactivation of inflammatory responses. However, the available monoclonal antibodies are limited in their application due to their complex preparation process, high price, and the lack of cell targeting ability leading to systemic toxicity and side effects. In this study, by using a genetic bioengineering technique, we modified TNF-R1 on the cell membrane surface-derived nanovesicles (NVs). We confirmed that TNF-R1 NVs stably expressed TNF-R1 on the membrane surface and interacted with its ligand TNF-α. Furthermore, TNF-R1 NVs competitively antagonized the effect of TNF-α in the wound healing assay in vitro. In the scalded mouse model, TNF-R1 NVs were released continuously from the thermosensitive hydrogel Pluronic F-127, resulting in less inflammation and better wound healing. Our results revealed TNF-R1 NVs as promising cell-free therapeutic agents in alleviating TNF-α-mediated pro-inflammatory signaling and promoting wound repair.

Inhibition of TNF-α improves the bladder dysfunction that is associated with type 2 diabetes

Diabetic bladder dysfunction (DBD) is common and affects 80% of diabetic patients. However, the molecular mechanisms underlying DBD remain elusive because of a lack of appropriate animal models. We demonstrate DBD in a mouse model that harbors hepatic-specific insulin receptor substrate 1 and 2 deletions (double knockout [DKO]), which develops type 2 diabetes. Bladders of DKO animals exhibited detrusor overactivity at an early stage: increased frequency of nonvoiding contractions during bladder filling, decreased voided volume, and dispersed urine spot patterns. In contrast, older animals with diabetes exhibited detrusor hypoactivity, findings consistent with clinical features of diabetes in humans. The tumor necrosis factor (TNF) superfamily genes were upregulated in DKO bladders. In particular, TNF-α was upregulated in serum and in bladder smooth muscle tissue. TNF-α augmented the contraction of primary cultured bladder smooth muscle cells through upregulating Rho kinase activity and phosphorylating myosin light chain. Systemic treatment of DKO animals with soluble TNF receptor 1 (TNFRI) prevented upregulation of Rho A signaling and reversed the bladder dysfunction, without affecting hyperglycemia. TNFRI combined with the antidiabetic agent, metformin, improved DBD beyond that achieved with metformin alone, suggesting that therapies targeting TNF-α may have utility in reversing the secondary urologic complications of type 2 diabetes.

Clinical development of onercept, a tumor necrosis factor binding protein, in psoriasis

BACKGROUND

Tumor necrosis factor (TNF)-α plays a critical role in psoriasis pathogenesis, and several anti-TNF agents have been developed as therapeutic drugs in this indication.

SCOPE

To present the preclinical rationale and clinical data for onercept, a novel anti-TNF agent developed for the treatment of moderate-to-severe psoriasis, and to critically evaluate the onercept clinical development program.

FINDINGS

Onercept was shown in preclinical studies to inhibit TNF-α and suppress clinical signs in several inflammatory conditions. In phase II studies onercept demonstrated a therapeutic benefit in psoriasis and psoriatic arthritis and no safety issues were identified. Based on these results, a phase III program comprising three multicenter, randomized, double-blind, placebo-controlled studies examining onercept in moderate-to-severe plaque psoriasis was initiated. Following the occurrence of two cases of systemic inflammatory response syndrome (SIRS) and lower than expected efficacy results, an independent Data Safety Monitoring Board (DSMB) determined that the risk-benefit ratio was not sufficiently favorable to justify continued development, and all clinical studies were promptly terminated. Although not initially diagnosed as such by the investigators, two further SIRS events were reported, one after study discontinuation. Although an increased incidence of infection and sepsis-like events has been associated with other anti-TNF therapies, an increased risk of infection was not observed with onercept treatment. Moreover, no infectious etiology was determined in the SIRS cases. The data suggest that the SIRS reactions were due to a systemic inflammatory response.

CONCLUSIONS

Despite promising early clinical results, onercept showed many of the expected risks associated with other anti-TNF agents and proved not to have an exceptional efficacy and safety profile. The clinical development of onercept highlights the critical importance of DSMBs and closely monitoring patient safety and evaluating risk-benefit profiles in large clinical programs.

[Role of a latent soluble TNF receptor type I (hsTNFRI) fusion protein in targeted treatment of endometriosis]

OBJECTIVE

To construct a latent human soluble tumor necrosis factor receptor I (hsTNFRI) using the latency associated protein (LAP) of transforming growth factor-beta1 (TGF-beta1) fused via a matrix metalloproteinase (MMP) cleavage site to hsTNFRI so as to detect the latent biological activity of LAP-MMP-hsTNFRI fusion protein.

METHODS

A double-stranded deoxyoligonucleotide coding for MMP cleavage site was cloned into plasmid pcDNA3.1. LAP and hsTNFRI cDNA were then inserted into both two sides of MMP cleavage site. After being transferred by LAP-MMP-hsTNFRI fusion gene with liposome, the expression of fusion protein in COS-7 cells was detected by RT-PCR and Western blot. The inhibitory effect of fusion protein upon cytotoxicity of TNF-alpha was detected by methyl thiazolyl tetrazolium (MTT) assay before and after the fusion protein incubated in MMP or peritoneal fluid from endometriosis patients.

RESULTS

The recombinant plasmid LAP-MMP-hsTNFRI-pcDNA3.1 was constructed successfully and was expressed effectively in COS-7 cells. The MTT assay showed that there was no difference in the mortality rate of L929 cells between LAP-MMP-hsTNFRI-pcDNA3.1 and empty vector transfection groups (P > 0.05). The mortality rates of L929 cells with 800 ng/L TNF-alpha in LAP-MMP-hsTNFRI-pcDNA3.1 transfection group after incubation with MMP or peritoneal fluid from endometriosis patients were (44.5 +/- 2.4)% and (33.8 +/- 1.9)% respectively. And it was lower than the pre-incubation period (58.1 +/- 2.4)% (P < 0.05).

CONCLUSION

The biological activity of LAP-MMP-hsTNFRI fusion protein can be made latent by LAP and activated by peritoneal fluid from endometriosis. Thus a new method has been provided for a targeted therapy of endometriosis.

Endometriosis: in search of optimal treatment

Endometriosis is an enigmatic, debilitating disease which affects as many as 15% of all women of reproductive age and is characterized by pelvic pain and infertility. Current treatment regimes used to manage the disease do so by inducing a hypoestrogenic state. While the absence of circulating estrogen levels lead to a regression of the disease, this hypoestrogenism also induces many unpleasant and unwanted side-effects. As such, these and other shortcomings of current drug therapies emphasize their limitations and the necessity for the development of novel endometriosis treatments. In this review, current therapies for medical management of endometriosis are discussed as are their shortcomings. Potential target areas which may be attractive alternatives to current therapies are also reviewed and include aromatase inhibitors, angiogenesis disruptors and anti-tumor necrosis factor-alpha inhibitors.

Biological therapy of inflammatory bowel disease

Ulcerative colitis (UC), Crohn's disease (CD) and indeterminate colitis are defined as inflammatory bowel diseases (IBD). Those diseases involve disorders of numerous immunological mechanisms associated with cellular and humoral immune response. In CD cellular response is considered to be of crucial importance, and dominant cytokines include: tumor necrosis factor alpha (TNF-alpha), interferon gamma (INF-gamma) and interleukins 1beta (IL-1beta), IL-2, IL-6, IL-8, IL-12. In UC, increased expression of Th2 (responsible for humoral response) is observed. It is connected with increased production of interleukins: 4 (IL-4), IL-5, IL-6, IL-10 and TNF-alpha. Lack of balance between pro-inflammatory and anti-inflammatory cytokines is of vital importance in pathogenesis of IBD. Conventional therapy of CD and UC quite commonly fails to bring satisfactory results, therefore an interest in new therapeutic options, that is, biological therapy, gene therapy, hematopoietic stem cell transplantation, and leucapheresis, has aroused recently. Biological therapy is focused on different stages of the inflammatory process. The fundamentals of biological strategy involve neutralization of pro-inflammatory cytokines, use of anti-inflammatory cytokines and inhibition of neutrophil adhesion. Biological therapy is a promising option because it enables to withdraw corticosteroids and immunosuppressive agents or to reduce their dose. Moreover, it shortens the hospital stay, allows to avoid surgical procedures, extends the remission period and improves patients' quality of life. Currently, 2 agents, infliximab and adalimumab, are registered for the biological therapy of CD in Poland.

Recombinant human TNF-binding protein-1 (rhTBP-1) treatment delays both symptoms progression and motor neuron loss in the wobbler mouse

TNF-alpha overexpression may contribute to motor neuron death in amyotrophic lateral sclerosis (ALS). We investigated the intracellular pathway associated with TNF-alpha in the wobbler mouse, a murine model of ALS, at the onset of symptoms. TNF-alpha and TNFR1 overexpression and JNK/p38MAPK phosphorylation occurred in neurons and microglia in early symptomatic mice, suggesting that this activation may contribute to motor neuron damage. The involvement of TNF-alpha was further confirmed by the protective effect of treatment with rhTNF-alpha binding protein (rhTBP-1) from 4 to 9 weeks of age. rhTBP-1 reduced the progression of symptoms, motor neuron loss, gliosis and JNK/p38MAPK phosphorylation in wobbler mice, but did not reduce TNF-alpha and TNFR1 levels. rhTBP-1 might possibly bind TNF-alpha and reduce the downstream phosphorylation of two main effectors of the neuroinflammatory response, p38MAPK and JNK.

Effects of tumor necrosis factor blockade on cardiovascular risk factors in psoriatic arthritis: A double-blind, placebo-controlled study

OBJECTIVE

To conduct a robust, double-blind, placebo-controlled study examining the effects of tumor necrosis factor (TNF) modulation on concentrations of traditional and novel cardiovascular disease risk factors in patients with an inflammatory condition.

METHODS

In this double-blind study, 127 patients with psoriatic arthritis (PsA) and active psoriasis were randomized to 1 of 3 treatment arms (placebo, onercept 50 mg, or onercept 100 mg for 12 weeks). Traditional and novel biochemical risk factors were evaluated at baseline and at the end of the treatment period.

RESULTS

At baseline, an elevated C-reactive protein (CRP) level correlated positively with lipoprotein(a) (Lp[a]), intercellular adhesion molecule 1, interleukin-6, and homocysteine levels but was inversely correlated with concentrations of all other lipid moieties and sex hormone binding globulin (SHBG). Onercept at a dose of 100 mg induced significant (P < or = 0.002) reductions in the levels of CRP (-14.0 versus 6.5 mg/liter with placebo), Lp(a) (-3.11 versus 1.52 mg/dl with placebo), and homocysteine (-1.72 versus 0.34 mumoles/liter with placebo) and an increase in the SHBG concentration (4.3 versus -1.3 mmoles/liter with placebo). The 100-mg dose of onercept was also associated with significant (P < 0.05) increases in the level of circulating apolipoprotein AI (Apo A-I) (4.0 versus -5.6 mg/dl with placebo); however, levels of Apo B (6.3 versus -0.4 mg/dl with placebo) and triglycerides (0.09 versus 0.04 mmoles/liter) were also increased.

CONCLUSION

This study is the first to demonstrate that targeting the TNF pathway can significantly decrease Lp(a) and homocysteine levels and elevate Apo A-I and SHBG concentrations. These data support an important precursor role for high-grade inflammation in modulating these putative risk parameters. However, TNF blockade-induced increases in triglyceride and Apo B levels were unexpected and suggest that it is not possible, on the basis of biochemical changes in isolation, to suggest that cardioprotection would necessarily follow; rather, direct measures of atherosclerotic progression with TNF blockade (e.g., using carotid ultrasound) would be better.

TNF-alpha neutralization ameliorates obstruction-induced renal fibrosis and dysfunction

Upper urinary tract obstruction results in tubulointerstitial fibrosis and a progressive decline in renal function. Although several inflammatory mediators have been implicated in the pathophysiology of renal obstruction, the contribution of TNF-alpha to obstruction-induced fibrosis and renal dysfunction has not been thoroughly evaluated. To study this, male Sprague-Dawley rats were subjected to left unilateral ureteral obstruction vs. sham operation. Rats received either vehicle or a pegylated form of soluble TNF receptor type 1 (PEG-sTNFR1) every 84 h. The kidneys were harvested 1, 3, or 7 days postoperatively, and tissue samples were analyzed for TNF-alpha expression (ELISA), macrophage infiltration (ED-1 staining), transforming growth factor-beta(1) expression (ELISA, RT-PCR), collagen I and IV activity (Western Blot, immunohistochemistry), alpha-smooth muscle actin accumulation (immunohistochemistry, Western blot analysis), and angiotensinogen expression (Western blot). In a separate arm, the glomerular filtration rate (inulin clearance) of rats subjected to unilateral ureteral obstruction in the presence of either vehicle or PEG-sTNFR1 was determined. Renal obstruction induced increased tissue TNF-alpha and transforming growth factor-beta(1) levels, collagen I and IV activity, interstitial volume, alpha-smooth muscle actin accumulation, angiotensinogen expression, and renal dysfunction, whereas treatment with PEG-sTNFR1 significantly reduced each of these markers of renal fibrosis. These results demonstrate that TNF-alpha mediates obstruction-induced renal fibrosis and identify TNF-alpha neutralization as a potential therapeutic option for the amelioration of obstruction-induced renal injury.

Anti-tumor necrosis factor agent PEG-sTNFRI improves the growth hormone/insulin-like growth factor-I system in adjuvant-induced arthritic rats

Adjuvant-induced arthritis is associated with body weight loss and decreased pituitary growth hormone (GH) and hepatic insulin-like growth factor-I (IGF-I) synthesis. Cytokines as tumor necrosis factor (TNF) mediate wasting associated with chronic inflammation. The aim of this study was to analyse whether the inhibition of TNF is able to revert the decrease in the body weight and the GH/IGF-I axis in arthritic rats. Male Wistar rats were injected with Freund's adjuvant, and 15 days later arthritic and control rats were daily injected with polyethylene glycol linked to soluble TNF receptor p55 (PEG-sTNFRI) (1 mg/kg, s.c.) or saline for 8 days. There was a significant decrease in pituitary GH mRNA (P<0.05), hepatic IGF-I mRNA (P<0.01) and serum concentrations of IGF-I (P<0.01) in arthritic rats. The 8-day administration of PEG-sTNFRI resulted in an increase in food intake (P<0.05) and body weight gain (P<0.01) in arthritic but not in control rats. There was an increase in pituitary GH mRNA after PEG-sTNFRI treatment both in control and in arthritic rats. There was a significant increase in IGF-I serum concentrations (P<0.05) and hepatic IGF-I mRNA expression (P<0.05) in control rats treated with PEG-sTNFRI, whereas the effect of this anti-TNF agent in arthritic rats was only statistically significant in hepatic IGF-I mRNA expression (P<0.05). These data suggest that TNF seems to be involved in the decrease in GH and IGF-I synthesis in arthritic rats.

Recombinant Human TNFRSF1A (r-hTBP1) Inhibits the Development of Endometriosis in Baboons: A Prospective, Randomized, Placebo- and Drug-Controlled Study1

Endometriosis is associated with chronic inflammation, including an increased macrophage activity with increased secretion of cytokines, such as tumor necrosis factor (TNF) or TNF superfamily member 2, previously known as TNFalpha. In the present study, we tested the hypothesis that recombinant human TNFRSF1A (r-hTBP1) can inhibit the development of endometriotic lesions in the baboon, an established model for the study of endometriosis. Endometriosis was induced using intrapelvic injection of menstrual endometrium in 20 baboons with a normal pelvis. In the first part of the study, 14 baboons were randomly assigned to subcutaneous treatment with r-hTBP1, placebo, or GnRH antagonist (positive control). In the second part of the study, menstrual endometrium from 6 baboons was randomly incubated with either PBS or r-hTBP1 before intrapelvic seeding. Video laparoscopy was performed 25 days later to document the number, surface area, and estimated volume of endometriotic lesions and adhesions; to calculate the revised American Fertility Society (rAFS) score and stage; and to confirm the histological presence of endometriosis. In the first part, baboons treated with r-hTBP1 or with Antide (Bachem) had a lower endometriosis rAFS score, a lower surface area and estimated volume of peritoneal endometriotic lesions, and a lower histological confirmation rate compared with controls. Because of less adnexal and cul-de-sac adhesions, the number of baboons with endometriosis of stage II, III, or IV was lower among baboons treated with r-hTBP1 or Antide than among controls. In the second part, the surface area of endometriotic lesions was lower, and less severe endometriosis was observed in r-hTBP1-treated baboons. No hypoestrogenic effects were observed in baboons treated with r-hTBP1. In conclusion, r-hTBP1 can effectively inhibit the development of endometriosis without hypoestrogenic effects in baboons.

A phase 2 dose-finding study of PEGylated recombinant methionyl human soluble tumor necrosis factor type I in patients with rheumatoid arthritis

OBJECTIVE

In a phase 2 study, to assess the efficacy and safety of pegsunercept, a soluble tumor necrosis factor receptor type I, for the treatment of rheumatoid arthritis (RA).

METHODS

Patients were randomized to receive weekly subcutaneous injections of placebo (n = 61) or active drug [400 microg/kg (n = 67) or 800 microg/kg (n = 66)] for 12 weeks. The primary efficacy endpoint was American College of Rheumatology 20% response (ACR20) at Week 12. Secondary efficacy measures included ACR50 and ACR70 responses, and changes in individual ACR components at Week 12. Safety assessments included summaries of adverse events including infectious episodes.

RESULTS

Treatment with pegsunercept resulted in a significantly higher ACR20 response at Week 12 in the 800 microg/kg group (45%) compared with the placebo group (26%; p = 0.020). The treatment effect of pegsunercept (both doses) over the study period showed statistically significant improvement for most ACR components and health related quality of life, with the 800 microg/kg group showing greater clinical improvements in efficacy measures. The overall incidence of adverse events and infectious episodes was similar among the treatment and placebo groups.

CONCLUSION

In this 12 week dose-finding study of 194 patients, weekly subcutaneous dosing with pegsunercept showed beneficial effects in improving the signs and symptoms of RA. It appeared to be safe and well tolerated in this small number of patients. Significant clinical improvements were seen in patients in the 800 microg/kg group; however, this dose may be suboptimal, and further evaluation of this product with higher doses or a more frequent dosing regimen is warranted.

Amelioration of inflammatory arthritis by targeting the pre-ligand assembly domain of tumor necrosis factor receptors

Tumor necrosis factor (TNF)-alpha has an important role in the pathogenesis of autoimmune and inflammatory diseases such as rheumatoid and septic arthritis. The biological effects of TNF-alpha are mediated by binding to TNF receptors TNFR1 (also known as P60) or TNFR2 (also known as P80). The pre-ligand assembly domain (PLAD) is a portion of the extracellular region of TNFRs that mediates receptor-chain association essential for signaling. We found that soluble versions of PLAD, especially those derived from P60, block the biochemical effects of TNF-alpha in vitro and potently inhibit arthritis in animal models. Thus, targeting the PLAD may have clinical value in the treatment of human arthritis and other disorders involving receptors of the TNFR superfamily.

Additive bone-protective effects of anabolic treatment when used in conjunction with RANKL and tumor necrosis factor inhibition in two rat arthritis models

OBJECTIVE

To investigate whether the bone-preserving effects of a RANKL antagonist or a tumor necrosis factor (TNF) antagonist could be further improved by the addition of a bone anabolic agent in inflammatory arthritis.

METHODS

Lewis rats with either adjuvant-induced arthritis (AIA) or collagen-induced arthritis (CIA) were treated for 10 days with PEGylated soluble tumor necrosis factor receptor type I (PEG sTNFRI), interleukin-1 receptor antagonist (IL-1Ra), osteoprotegerin (OPG), parathyroid hormone (PTH), or combinations of these agents starting on day 4 after disease onset. Treatment effects were assessed clinically, radiologically, and histologically, and by morphometry for the extent of paw swelling, bone erosive changes, and synovial inflammation.

RESULTS

Paw swelling and synovial inflammation were significantly inhibited by PEG sTNFRI in AIA and CIA, and by IL-1Ra in CIA. OPG and PTH had no significant effect on these parameters. Analysis of bone erosion revealed a significant bone-sparing effect of monotherapy with PEG sTNFRI or OPG in both models, whereas IL-1Ra was only effective in CIA. PTH treatment alone did not show a bone-protective effect in either model. With the combination of PEG sTNFRI and PTH, erosion scores (-74% in AIA and -61% in CIA versus controls) were significantly lower than those elicited by PEG sTNFRI alone (-41% and -29%, respectively, versus controls). Similar results were also obtained with the combination of OPG and PTH (-88% in AIA and -73% in CIA, compared with -70% and -55%, respectively, with OPG monotherapy). Coadministration of IL-1Ra and PTH had no synergistic bone-sparing effect. Morphometric analysis revealed that the addition of PTH to PEG sTNFRI or OPG resulted in higher bone volume and higher osteoblast numbers in both AIA and CIA.

CONCLUSION

The bone-protective effects resulting from RANKL or TNF antagonism can be further improved by the addition of a bone anabolic agent.