A treadmill exercise reduced cardiac fibrosis, inflammation and vulnerability to ischemia-reperfusion in rat pristane-induced arthritis

AIMS

To explore cardiac structural and functional parameters and myocardial sensitivity to ischemia in a rat model of chronic arthritis, pristane-induced arthritis (PIA), and to investigate the effects of a running exercise protocol on cardiac disorders related to rheumatoid arthritis (RA).

MAIN METHODS

3 groups of male Dark Agouti rats were formed: Controls, PIA and PIA-Exercise. The PIA-Exercise group was subjected to an individualized treadmill running protocol during the remission phase. At acute and chronic phases of PIA, cardiac structure was analyzed by histology. Cardiac function was explored in isolated hearts to measure left ventricular developed pressure (LVDP), cardiac compliance and infarct size before and after ischemia/reperfusion. Cardiac inflammation was evaluated through VCAM-1 mRNA expression by RT-qPCR. Plasma irisin levels were measured by ELISA.

KEY FINDINGS

PIA rats exhibited myocardial hypertrophy fibrosis and inflammation at the 2 inflammatory phases of the model. At chronic phase only, LVDP and cardiac compliance were lower in PIA compared to controls. As compared to sedentary PIA, exercise did not change cardiac function but reduced fibrosis, inflammation, infarct size, and arthritis severity and increased irisin levels. Cardiac inflammation positively correlated with fibrosis, while irisin levels negatively correlated with cardiac inflammation and fibrosis.

SIGNIFICANCE

In the PIA model that recapitulated most cardiac disorders of RA, a daily program of treadmill running alleviated cardiac fibrosis and inflammation and improved resistance to ischemia. These data provide arguments to promote the practice of exercise in RA patients for cardiac diseases prevention.

Identification of PCPE-2 as the endogenous specific inhibitor of human BMP-1/tolloid-like proteinases

BMP-1/tolloid-like proteinases (BTPs) are major players in tissue morphogenesis, growth and repair. They act by promoting the deposition of structural extracellular matrix proteins and by controlling the activity of matricellular proteins and TGF-β superfamily growth factors. They have also been implicated in several pathological conditions such as fibrosis, cancer, metabolic disorders and bone diseases. Despite this broad range of pathophysiological functions, the putative existence of a specific endogenous inhibitor capable of controlling their activities could never be confirmed. Here, we show that procollagen C-proteinase enhancer-2 (PCPE-2), a protein previously reported to bind fibrillar collagens and to promote their BTP-dependent maturation, is primarily a potent and specific inhibitor of BTPs which can counteract their proteolytic activities through direct binding. PCPE-2 therefore differs from the cognate PCPE-1 protein and extends the possibilities to fine-tune BTP activities, both in physiological conditions and in therapeutic settings.

Relevance of circulating markers of endothelial activation for cardiovascular risk assessment in rheumatoid arthritis: a narrative review

Rheumatoid arthritis (RA) is associated with excessive cardiovascular mortality secondary to premature atherosclerosis, in which endothelial activation (EA) plays a central role. EA is characterized by loss of vascular integrity, expression of leucocyte adhesion molecules, transition from antithrombotic to prothrombotic phenotype, cytokines production, shedding of membrane microparticles and recruitment of endothelial progenitor cells. As EA is an early event in atherogenesis, circulating markers of EA are putative markers of vascular pathology and cardiovascular (CV) risk. After a presentation of biology of EA, the present review analyzed the available data regarding changes in EA markers in RA in link with the vascular pathology and CV events, discussed their relevance as biomarkers of CV risk and proposed future directions.

POS0418 ICE CRYOTHERAPY: A NEW STRATEGY TO REDUCE ARTERIAL INFLAMMATION IN RHEUMATOID ARTHRITIS? A STUDY IN ADJUVANT-INDUCED ARTHRITIS MODEL

Background

Rheumatoid arthritis (RA) is characterized by endothelial activation (EA), endothelial dysfunction and vascular inflammation, leading to accelerated atherosclerosis. In the last decade, a renewed interest in cryotherapy - local or whole body - has emerged. Although growing evidence demonstrated that ice cryotherapy reduces not only pain but also disease progression, whether such therapy might blunt disorders of the systemic vasculature is unknown.

Objectives

The aim of our study was to determine the effects of a subchronic treatment with ice cryotherapy on aortic leucocyte infiltration and markers of endothelial activation in the rat adjuvant-induced arthritis (AIA) model.

Methods

AIA was induced by injection of Mycobacterium butyricum in Freund’s incomplete adjuvant at the base of the tail in 6-week-old male Lewis rats. AIA rats were treated or not with ice applied on paws, from the onset of arthritis to the acute inflammatory stage of the disease, twice a day for 14 days. Arthritis score and paw skin temperature were daily monitored. At the end of the treatment, leucocyte infiltration and the different cell subsets (monocytes/macrophages, neutrophils, CD4+ and CD8+ T cells producing or not IL-17A) were measured in thoracic aorta using flow cytometry. Relative mRNA expression of cytokines/chemokines (IL-6, TNF-α, CXCL-1, MIP-1α (CCL-3), MCP-1 (CCL-2)) and adhesion molecules (ICAM-1, VCAM-1) was analyzed in thoracic aorta by RT-qPCR. X-Ray analysis of hind paws was performed to assign a radiographic score.

Results

Treatment with ice cryotherapy, that decreased skin surface temperature from 28.6 ± 0.3°C to 18.5 ± 0.2°C, reduced arthritis score (-36%, p<0.001) and radiographic score (-34%, p<0.05) with a positive effect on osteoporosis, cartilage and bone destruction. These effects were associated with a dramatic decrease in CD4+, CD8+ and Tc17 cell aortic infiltration as compared to untreated AIA. By contrast, ice had no effect on endothelial activation markers except VCAM-1 mRNA expression that was significantly increased (p<0.05). A positive correlation was found between the number of total leucocytes, monocytes/macrophages, CD4+ and CD8+ T cells in aorta and arthritis score.

Conclusion

In the model of AIA that reproduces arterial wall inflammation recently characterized in rheumatoid arthritis by PET/CT [1], local ice cryotherapy exerts not only local beneficial effects on the joints but also systemic benefits on vascular inflammation in large vessels. These results suggest that reduction of vascular comorbidities might be a new output of ice cryotherapy used as an adjunctive therapy in RA.

References

[1]Agca et al. Rheumatology (Oxford) (2021)

Disclosure of Interests

None declared.

Effects of local cryotherapy on systemic endothelial activation, dysfunction, and vascular inflammation in adjuvant-induced arthritis (AIA) rats

Aim

This study explored the systemic vascular effects of local cryotherapy with a focus on endothelial changes and arterial inflammation in the model of rat adjuvant-induced arthritis (AIA).

Methods

Cryotherapy was applied twice a day on hind paws of AIA rats from the onset of arthritis to the acute inflammatory phase. Endothelial activation was studied in the aorta by measuring the mRNA levels of chemokines (CXCL-1, MCP-1 (CCL-2), MIP-1α (CCL-3)) and adhesion molecules (ICAM-1, VCAM-1) by qRT-PCR. Endothelial dysfunction was measured in isolated aortic and mesenteric rings. Aortic inflammation was evaluated via the mRNA expression of pro-inflammatory cytokines (TNF-α, IL-6) by qRT-PCR and leucocyte infiltration analysis (flow cytometry). Plasma levels of TNF-α, IL-6, IL-1β, IL-17A, and osteoprotegerin (OPG) were measured using Multiplex/ELISA.

Results

AIA was associated with an increased aortic expression of CXCL-1 and ICAM-1 as well as an infiltration of leucocytes and increased mRNA expression of IL-6, IL-1β, and TNF-α. Local cryotherapy, which decreased arthritis score and structural damages, reduced aortic mRNA expression of CXCL-1, IL-6, IL-1β, and TNF-α, as well as aortic infiltration of leucocytes (T lymphocytes, monocytes/macrophages, neutrophils) and improved acetylcholine-induced vasorelaxation in the aorta and mesenteric arteries. Plasma levels of IL-17A and OPG were significantly reduced by cryotherapy, while the number of circulating leucocytes was not. IL-17A levels positively correlated with endothelial activation and dysfunction.

Conclusion

In the AIA model, local cryotherapy reduced systemic endothelial activation, immune cell infiltration, and endothelial dysfunction. Mechanistically, the reduction of circulating levels of IL-17A appears as the possible link between joint cooling and the remote vascular effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02774-1.

Tofacitinib improved peripheral endothelial dysfunction and brain-derived neurotrophic factor levels in the rat adjuvant-induced arthritis model

This study aimed to explore the effect of Tofacitinib on endothelial dysfunction and cerebral levels of brain-derived neurotrophic factor (BDNF) in the adjuvant-induced arthritis (AIA) rat model. Tofacitinib (10 mg/kg twice a day) or vehicle was administered from the first signs of inflammation. Arthritis scores were daily monitored while other parameters including endothelial function assessed from aortic rings, radiographic scores, blood pressure, heart rate, circulating levels of triglycerides, cholesterol, and interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), IL-17A, and cerebral BDNF levels were determined after 3 weeks of treatment. A group of non-AIA rats served as controls. In AIA rats, as compared with vehicle, Tofacitinib significantly reduced arthritis and radiographic scores, decreased total cholesterol and low-density lipoprotein cholesterol (LDL-C), but changed neither blood pressure nor heart rate and proinflammatory cytokines levels. It also fully restored acetylcholine (Ach)-induced relaxation (p < 0.05) through increased nitric oxide (NO) synthase activity, reduced BH₄ deficiency and O₂ ^-° production, decreased cyclo-oxygenase-2 (COX-2)/arginase activities, and enhanced endothelium-derived hyperpolarizing factor (EDHF) production. These effects translated into a decrease in atherogenic index and an elevation of BDNF levels in the prefrontal cortex (p < 0.05) and hippocampus (p < 0.001). The present study identified Tofacitinib as an efficient therapeutic option to reduce cardiovascular risk and improve BDNF-dependent cognition in arthritis.

AB0062 TIME COURSE OF INTESTINAL PERMEABILITY AND BACTERIAL TRANSLOCATION IN THE MODEL OF ADJUVANT-INDUCED ARTHRITIS

Background:

Intestinal inflammation, dysbiosis, intestinal permeability (IP) and bacterial translocation (BT) have been identified in patients with spondyloarthritis but the time at which they appear and their contribution to the pathogenesis of the disease is still a matter of debate.

Objectives:

To investigate the time-course of intestinal inflammation, IP and BT in a rat model of reactive arthritis, a subgroup of SpA, the adjuvant-induced arthritis model.

Methods:

Adjuvant-induced arthritis (AIA) was induced in 6-week-old male Lewis rats by an injection at the base of the tail of Mycobacterium butyricum with incomplete Freund’s adjuvant (Day (D) 0). Control rats received saline using the same procedure. Body weights and a clinical arthritis score were daily assessed. A group of AIA and control rats (n=15 per group) were euthanized at three different times of arthritis: D4 for the pre-arthritic phase (AIA-preclinical), D11 for the onset of arthritis (AIA-onset) and D28 for the acute phase (AIA-acute). In each group (AIA and control, n=15 per group)), IP was assessed by measuring plasma levels of zonulin (ELISA) and ileal mRNA expression of zonulin and occludin (RT-qPCR), BT was studied by measuring bacterial endotoxins (or LPS, by LCMS2 method), soluble CD-14 (sCD14, ELISA) and ileal mRNA expression of TLR-4, and intestinal inflammation was assessed by measuring ileal mRNA expression of IL-8, IL-33, IL-17, IL-23p19 and TNF-α (RT-qPCR). Joint damage was assessed by the determination of a clinical and radiographic score of hind paws.

Results:

Body weights of AIA rats decreased from D4 to D28 as compared to controls, in parallel to the development of a severe clinical and radiographic arthritic disease from D11 and D28. Compared to control rats, AIA induced an increase in plasma zonulin levels at D4, D11 but not at D28. Ileal mRNA zonulin overexpression occurred at D11 while occludin was unchanged. As early as Day 4 (preclinical phase), mRNA of IL-8, IL-33 and IL-17 were overexpressed in ileum from AIA. At Day 11 (onset), overexpression of IL-8 persisted and mRNA of TNF-α and IL-23p19 increased in AIA. Neither LPS levels nor ileal mRNA expression of TLR-4 were changed by arthritis whatever the phase of arthritis. By contrast, blood levels of sCD-14 was significantly increased in the AIA group at all stages of arthritis. No correlation was found between clinical and radiographic arthritis scores and zonulin or LPS levels. Conversely, a negative correlation was observed between intestinal IL-8 mRNA expression and arthritis score (r=-0.3, p=0.02).

Conclusion:

In an animal model of SpA, intestinal inflammation and increased intestinal permeability occur prior to joint inflammation, suggesting a role of these disorders in the pathogenesis of this disease.

Acknowledgements:

I would like to thank the Société Française de Rhumatologie for its support in this work.

Disclosure of Interests:

None declared

SAT0021 STRUCTURAL EFFECTS OF LOCAL CRYOTHERAPY IN RHEUMATOID ARTHRITIS: A STUDY IN ADJUVANT-INDUCED ARTHRITIS

Background:

The control of joint destruction caused by rheumatoid arthritis (RA) is a key issue in the treatment of this disease. Recent evidence showed that radiographic progression of joint damage occur despite a sharp decrease in disease activity and the use of aggressive Disease Modifying Anti-Rheumatic Drug (DMARD) therapies [1]. Whether alternative treatments such as cryotherapy may have beneficial effects on joint destruction at the early stages of the disease remains to be demonstrated, but such strategy would be of interest as it would not interfere with DMARDs treatment.

Objectives:

The aim of this study was to evaluate the effect of a 14-days-treatment of local cryotherapy on radiological outcomes in rat adjuvant induced arthritis.

Methods:

Adjuvant-induced arthritis (AIA) was induced in 6-weeks old male Lewis rats by injection ofMycobacterium butyricumin Freund’s incomplete adjuvant at the basis of the tail. A control group received saline. At the onset of arthritis, AIA rats were treated or not by application of cryotherapy on paws using either a cold spray or ice, twice a day for 14 days. Arthritis score and paws skin temperature was daily monitored. At the end of treatment, radiological exam of hind paws was performed and a score taking into account (swelling, osteoporosis, cartilage destruction, bone erosion, bone destruction and new bone formation) was assigned, according to Ackermanet al[2]. Circulating levels of cytokines (IL-6, IL-1β, TNF-α) was measured by Magpix Luminex kit.

Results:

Compared to untreated AIA, local cryotherapy significantly reduced the progression of arthritis score, whatever the modality (p<0.05), and to the same extent (reduction of arthritis score at day 24 post-immunization: -38% with cold spray, p<0.01, -37% with ice, p<0.01). Radiological score was significantly reduced by both treatments with no difference between the two treatments (-33% with cold spray, p<0.01, -44% with ice, p<0.01). All the items of the radiological score were equally reduced by ice and cold spray except swelling that was significantly reduced only by ice. Interestingly, the use of the cold spray induced a greater decrease in the skin temperature than the ice treatment (18.32 ± 0.07 °C vs 20.46 ± 0.08 °C, p<0.001). Conversely, cryotherapy did not significantly change the level of cytokines. No correlation was found between radiological score and arthritis score or cytokine levels.

Conclusion:

These data demonstrated that local cryotherapy had positive effects on structural damage in adjuvant-induced arthritis. The mechanisms involved remain now to be determined. These results suggest that local cryotherapy would be an interesting complement to conventional DMARDs in early RA.

References:

[1] Ten Klooster, P. M.et al.Radiographic progression can still occur in individual patients with low or moderate disease activity in the current treat-to-target paradigm: real-world data from the Dutch Rheumatoid Arthritis Monitoring (DREAM) registry.Arthritis Res. Ther.21, 237 (2019).

[2] Ackerman, N. R.et al.Effects of naproxen on connective tissue changes in the adjuvant arthritic rat.Arthritis Rheum.22, 1365–1374 (1979).

Disclosure of Interests:

Célian Peyronnel: None declared, Valentin Petitcolin: None declared, Perle Totoson: None declared, Hélène Martin: None declared, Frank Verhoeven: None declared, Céline Demougeot Grant/research support from: With an institutional support from Pfizer.