POS0383 EFFECTS OF TOFACITINIB THERAPY ON ARGININE AND METHIONINE METABOLITES IN ASSOCIATION WITH VASCULAR PATHOPHYSIOLOGY IN RHEUMATOID ARTHRITIS: A METABOLOMIC APPROACH

Background:

Rheumatoid arthritis (RA) has been associated with increased cardiovascular (CV) risk and metabolic changes.

Objectives:

We wished to determine how the Janus kinase (JAK) inhibitor tofacitinib influences vascular pathophysiology and metabolites of the arginine and methionine-homocysteine pathways.

Methods:

Thirty RA patients with active disease were treated with either 5 mg bid or 10 mg bid tofacitinib and evaluated at baseline and after 6 and 12 months. We determined DAS28, CRP, IgM rheumatoid factor (RF) and anti-cyclic citrullinated peptide (aCCP) levels. We assessed brachial artery flow-mediated vasodilation (FMD), carotid intima-media thickness (IMT) and pulse-wave velocity (PWV) by ultrasound. We also determined plasma L-arginine, L-citrulline, L-ornithine, inducible nitric oxide synthase (iNOS), asymmetric (ADMA) and symmetric dimethylarginine (SDMA), L-N-monomethyl-arginine (L-NMMA), cysteine, homocysteine, and methionine levels.

Results:

Twenty-six patients completed the study. Tofacitinib treatment maintained FMD and PWV. Ten mg bid tofacitinib significantly increased L-arginine, L-ornithine, iNOS and methionine levels after 12 months. Tofacitinib transiently increased L-citrulline and L-NMMA and decreased homocysteine levels after 12 months. Based on L-citrulline, L-ornithine, ADMA and SDMA levels, L-arginine remained highly available for endothelial NO production. Multivariate analysis indicated variable correlations of L-arginine, L-citrulline, ADMA, L-NMMA, homocysteine and methionine with DAS28, CRP, ESR and RF but not with aCCP. Regarding vascular pathophysiology, only PWV and methionine correlated with each other after 12 months.

Conclusion:

Tofacitinib suppressed systemic inflammation in RA yielding stabilization of vascular function. It may exert CV protective effects in RA, at least in part, by shifting L-arginine metabolism to high arginine availability and decreasing homocysteine levels.

Acknowledgements:

This research was supported by the European Union and the State of Hungary and co-financed by the European Social Fund in the framework of TAMOP-4.2.4.A/2-11/1-2012-0001 ‘National Excellence Program ’(Z.S.); by the European Union grant GINOP-2.3.2-15-2016-00015 (Z.S.) and by the WI188341 investigator-initiated research (IIR) grant obtained from Pfizer US (Z.S.).

Disclosure of Interests:

Boglárka Soós: None declared, Attila Hamar: None declared, Anita Pusztai: None declared, Monika Czókolyová: None declared, Edit Végh: None declared, Szilvia Szamosi Speakers bureau: Roche, Zsófia Pethö: None declared, Katalin Gulyás: None declared, György Kerekes: None declared, Éva Szekanecz: None declared, Sándor Szántó Speakers bureau: Abbvie, MSD, Novartis, Consultant of: Abbvie, Novartis, Gabriella Szücs Speakers bureau: Actelion, Roche, Sager, Boehringer, Consultant of: Boehringer, Actelion, Sager, Uwe Christians: None declared, Jelena Klawitter: None declared, Tamas Seres: None declared, Zoltán Szekanecz Speakers bureau: Pfizer, Abbvie, Roche, Lilly, Novartis, Boehringer, Consultant of: Pfizer, Abbvie, Novartis, Grant/research support from: Pfizer

Single dose of 17β-estradiol provides transient neuroprotection in female juvenile mice after cardiac-arrest and cardiopulmonary resuscitation

Each year there are approximately 7000 out of hospital cardiac arrests in the pediatric population, with 30% resuscitation rate and a 6-10% rate of survival to hospital discharge. Survivors of cardiac arrest exhibit learning and memory deficits that are devastating during the school years. Delayed neuronal cell death occurs in the hippocampus following cardiac arrest and likely contributes to memory impairments. Circulating endogenous estrogen in young adult females has been shown to provide protection against ischemic cell death, as does chronic exogenous administration of 17β-estradiol (E2). Chronic estrogen benefit can have undesirable feminizing effects, particularly in pre-adolescents. Here, we tested if a single-dose of E2 is neuroprotective in our pediatric cardiac arrest mouse model performed in juvenile mice. We subjected P21P25 C57Blk6 male and female mice to 8 min of cardiac arrest followed by cardiopulmonary resuscitation (CA/CPR). This developmental stage preceded the hormonal onset and serum estradiol and testosterone levels were not different in males and females. A single dose of E2 (100μg/kg) or vehicle was administered 30 min after resuscitation. Neuronal cell death measured 3 days after CA/CPR showed reduced hippocampal cell death in E2-treated females, but not males. Benefit of E2 in females was blocked by the P38 MAPK inhibitor, SB203580. Hippocampal-dependent memory function was equally impaired in E2-and vehicle-treated females measured in the contextual fear conditioning task at 7 days. Our findings demonstrate female-specific transient neuroprotection with E2 that does not provide sustained functional benefit.

Time-dependent effects of imatinib in human leukaemia cells: a kinetic NMR-profiling study

The goal of this study was to evaluate the time course of metabolic changes in leukaemia cells treated with the Bcr-Abl tyrosine kinase inhibitor imatinib. Human Bcr-Abl⁺ K562 cells were incubated with imatinib in a dose-escalating manner (starting at 0.1 μM with a weekly increase of 0.1 μM imatinib) for up to 5 weeks. Nuclear magnetic resonance spectroscopy and liquid-chromatography mass spectrometry were performed to assess a global metabolic profile, including glucose metabolism, energy state, lipid metabolism and drug uptake, after incubation with imatinib. Initially, imatinib treatment completely inhibited the activity of Bcr-Abl tyrosine kinase, followed by the inhibition of cell glycolytic activity and glucose uptake. This was accompanied by the increased mitochondrial activity and energy production. With escalating imatinib doses, the process of cell death rapidly progressed. Phosphocreatine and NAD⁺ concentrations began to decrease, and mitochondrial activity, as well as the glycolysis rate, was further reduced. Subsequently, the synthesis of lipids as necessary membrane precursors for apoptotic bodies was accelerated. The concentrations of the Kennedy pathway intermediates, phosphocholine and phosphatidylcholine, were reduced. After 4 weeks of exposure to imatinib, the secondary necrosis associated with decrease in the mitochondrial and glycolytic activity occurred and was followed by a shutdown of energy production and cell death. In conclusion, monitoring of metabolic changes in cells exposed to novel signal transduction modulators supplements molecular findings and provides further mechanistic insights into longitudinal changes of the mitochondrial and glycolytic pathways of oncogenesis.

FEA analysis of silicone MCP implant

This paper discusses finite element study of silicone rubber prosthesis for the metacarpophalangeal joint of the hand. Based on the experimental data, a material model which incorporates test data available for different stress states was chosen and calibrated. Finite element models for three commercially available silicone joint prosthesis were developed. All models incorporated the same material model and allowed for large deformations. These models were validated against the experimental data and analyzed under demanding loading conditions. Results such as highly non-linear material behavior, dependence on the loading history and large deformations near wrinkle formation in the hinge area of the joint clearly show the necessity and importance of using multi-stress- state non-linear material models and accounting for large deformations.