Aspirin as a COX inhibitor and anti-inflammatory drug in human skeletal muscle

Although aspirin is one of the most common anti-inflammatory drugs in the world, the effect of aspirin on human skeletal muscle inflammation is almost completely unknown. This study examined the potential effects and related time course of an orally consumed aspirin dose on the inflammatory prostaglandin E2 (PGE2)/cyclooxygenase (COX) pathway in human skeletal muscle. Skeletal muscle biopsies were taken from the vastus lateralis of 10 healthy adults (5 male and 5 female, 25 ± 2 yr old) before (Pre) and 2, 4, and 24 h after (Post) a standard dose (975mg) of aspirin and partitioned for analysis of 1) in vivo PGE2 levels in resting skeletal muscle and 2) ex vivo skeletal muscle PGE2 production when stimulated with the COX substrate arachidonic acid (5 μM). PGE2 levels in vivo and PGE2 production ex vivo were generally unchanged at each time point after aspirin consumption. However, most individuals clearly showed suppression of PGE2, but at varying time points after aspirin consumption. When the maximum suppression after aspirin consumption was examined for each individual, independent of time, PGE2 levels in vivo (184 ± 17 and 104 ± 23pg/g wet wt at Pre and Post, respectively) and PGE2 production ex vivo (2.74 ± 0.17 and 2.09 ± 0.11pg·mg wet wt−1·min−1 at Pre and Post, respectively) were reduced ( P < 0.05) by 44% and 24%, respectively. These results provide evidence that orally consumed aspirin can inhibit the COX pathway and reduce the inflammatory mediator PGE2 in human skeletal muscle. Findings from this study highlight the need to expand our knowledge regarding the potential role for aspirin regulation of the deleterious influence of inflammation on skeletal muscle health in aging and exercising individuals. NEW & NOTEWORTHY This study demonstrated that orally consumed aspirin can target the prostaglandin/cyclooxygenase pathway in human skeletal muscle. This pathway has been shown to regulate skeletal muscle metabolism and inflammation in aging and exercising individuals. Given the prevalence of aspirin consumption, these findings may have implications for skeletal muscle health in a large segment of the population.

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Mitochondrial H2Sn-Mediated Anti-Inflammatory Theranostics

Nano-Micro Letters ◽

10.1007/s40820-021-00689-1 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Won Young Kim ◽

Miae Won ◽

Seyoung Koo ◽

Xingcai Zhang ◽

Jong Seung Kim

Keyword(s):

Mouse Models ◽

Live Cells ◽

In Vivo Model ◽

Prostaglandin E ◽

Therapeutic Effects ◽

Microscopy Imaging ◽

Theranostic Agent ◽

Cox Inhibitor ◽

Anti Inflammatory

AbstractThe insistent demand for space-controllable delivery, which reduces the side effects of non-steroidal anti-inflammatory drugs (NSAIDs), has led to the development of a new theranostics-based approach for anti-inflammatory therapy. The current anti-inflammatory treatments can be improved by designing a drug delivery system responsive to the inflammatory site biomarker, hydrogen polysulfide (H2Sn). Here, we report a novel theranostic agent 1 (TA1), consisting of three parts: H2Sn-mediated triggering part, a two-photon fluorophore bearing mitochondria targeting unit (Rhodol-TPP), and anti-inflammatory COX inhibitor (indomethacin). In vitro experiments showed that TA1 selectively reacts with H2Sn to concomitantly release both Rhodol-TPP and indomethacin. Confocal-microscopy imaging of inflammation-induced live cells suggested that TA1 is localized in the mitochondria where the H2Sn is overexpressed. The TA1 reacted with H2Sn in the endogenous and exogenous H2Sn environments and in lipopolysaccharide treated inflammatory cells. Moreover, TA1 suppressed COX-2 level in the inflammatory-induced cells and prostaglandin E2 (PGE2) level in blood serum from inflammation-induced mouse models. In vivo experiments with inflammation-induced mouse models suggested that TA1 exhibits inflammation-site-elective drug release followed by significant therapeutic effects, showing its function as a theranostic agent, capable of both anti-inflammatory therapy and precise diagnosis. Theranostic behavior of TA1 is highly applicable in vivo model therapeutics for the inflammatory disease.

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Effects of Lipid-Lowering Drugs on Irisin in Human Subjects In Vivo and in Human Skeletal Muscle Cells Ex Vivo

PLoS ONE ◽

10.1371/journal.pone.0072858 ◽

2013 ◽

Vol 8 (9) ◽

pp. e72858 ◽

Cited By ~ 71

Author(s):

Ioanna Gouni-Berthold ◽

Heiner K. Berthold ◽

Joo Young Huh ◽

Reena Berman ◽

Nadine Spenrath ◽

...

Keyword(s):

Skeletal Muscle ◽

Human Skeletal Muscle ◽

Ex Vivo ◽

Human Subjects ◽

Muscle Cells ◽

Skeletal Muscle Cells ◽

Lipid Lowering ◽

Lipid Lowering Drugs ◽

Human Skeletal Muscle Cells

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Exercise increases phosphorylation of the putative mTORC2 activity readout NDRG1 in human skeletal muscle

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00389.2021 ◽

2021 ◽

Author(s):

Jonas Roland Knudsen ◽

Kaspar W Persson ◽

Jaroslawna Meister ◽

Christian Strini Carl ◽

Steffen H Raun ◽

...

Keyword(s):

Skeletal Muscle ◽

Human Skeletal Muscle ◽

Ex Vivo ◽

Vastus Lateralis ◽

Published Data ◽

Vastus Lateralis Muscle ◽

Mouse Muscle ◽

Exercise Induced ◽

Stimulation Of

In mice, exercise is suggested to activate the mechanistic target of rapamycin complex 2 (mTORC2) in skeletal muscle, and mTORC2 is required for normal muscle glucose uptake during exercise. Whether this translates to human skeletal muscle and what signaling pathways facilitate the exercise-induced mTORC2 activation is unknown but important to determine given the important role of mTORC2 in metabolism. We herein tested the hypothesis that exercise increases mTORC2 activity in human skeletal muscle and investigated if β2-adrenergic receptor (AR) activation mediates exercise-induced mTORC2 activation. We examined several mTORC2 activity readouts (p-NDRG1 Thr346, p-Akt Ser473, p-mTOR S2481, and p-Akt Thr450) in human skeletal muscle biopsies after uphill walking or cycling exercise. In mouse muscles, we assessed mTORC2 activity readouts following acute activation of muscle β2-adrenergic or Gs signaling and during in vivo and ex vivo muscle contractions. Exercise increased phosphorylation of NDRG1 Thr346 in human soleus, gastrocnemius, and vastus lateralis muscle, without changing p-Akt Ser473, p-Akt Thr450, and p-mTOR Ser2481. In mouse muscle, stimulation of β2-adrenergic or Gs signaling and ex vivo contractions failed to increase p-NDRG1 Thr346, while in vivo contractions were sufficient to induce p-NDRG1 Thr346. In conclusion, the mTORC2 activity readout p-NDRG1 Thr346 is a novel exercise-responsive signaling protein in human skeletal muscle. Notably, contraction-induced p-NDRG1 Thr346 appears to require a systemic factor. Unlike exercise, and in contrast to published data obtained in cultured muscles cells, stimulation of β2-adrenergic signaling is not sufficient to trigger NDRG1 phosphorylation in mature mouse skeletal muscle.

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Cyclooxygenase inhibition does not impact the pressor response during static or dynamic mechanoreflex activation in healthy decerebrate rats

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00080.2019 ◽

2019 ◽

Vol 317 (3) ◽

pp. R369-R378 ◽

Cited By ~ 4

Author(s):

Korynne S. Rollins ◽

Tyler D. Hopkins ◽

Alec L. Butenas ◽

Kennedy P. Felice ◽

Carl J. Ade ◽

...

Keyword(s):

Skeletal Muscle ◽

Pressor Response ◽

Muscle Afferents ◽

Triceps Surae ◽

Prostaglandin E ◽

Muscle Stretch ◽

Triceps Surae Muscle ◽

Cox Inhibitor

Passive limb movement and limb muscle stretch in humans and animals are common experimental strategies used to investigate activation of the muscle mechanoreflex independent of contraction-induced metabolite production. Cyclooxygenase (COX) metabolites, however, are produced by skeletal muscle stretch in vitro and have been found to impact various models of mechanoreflex activation. Whether COX metabolites influence the decerebrate rat triceps surae muscle stretch mechanoreflex model remains unknown. We examined the effect of rat triceps surae muscle stretch on the interstitial concentration of the COX metabolite prostaglandin E2 (PGE2). Interstitial PGE2 concentration was increased above baseline values by 4 min of both static (38% increase, P = 0.01) and dynamic (56% increase, P < 0.01) triceps surae muscle stretch ( n = 10). The 4-min protocol was required to collect enough microdialysis fluid for PGE2 detection. The finding that skeletal muscle stretch in vivo was capable of producing COX metabolites prompted the hypothesis that intra-arterial administration of the COX inhibitor indomethacin (1 mg/kg) would reduce the pressor and cardioaccelerator responses evoked during 30 s (the duration most commonly used in the rat mechanoreflex model) of static and dynamic rat triceps surae muscle stretch. We found that indomethacin had no effect ( P > 0.05, n = 9) on the pressor or cardioaccelerator response during 30 s of either static or dynamic stretch. We conclude that, despite the possibility of increased COX metabolite concentration, COX metabolites do not activate or sensitize thin-fiber muscle afferents stimulated during 30 s of static or dynamic hindlimb skeletal muscle stretch in healthy rats.

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Intracellular energetics and critical Po2 in resting ischemic human skeletal muscle in vivo

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00225.2010 ◽

2010 ◽

Vol 299 (5) ◽

pp. R1415-R1422 ◽

Cited By ~ 11

Author(s):

Ian R. Lanza ◽

Michael A. Tevald ◽

Douglas E. Befroy ◽

Jane A. Kent-Braun

Keyword(s):

Skeletal Muscle ◽

Human Skeletal Muscle ◽

Ex Vivo ◽

High Energy ◽

Resonance Spectroscopy ◽

High Energy Phosphates ◽

Atp Production ◽

Resting Muscle

During ischemia and some types of muscular contractions, oxygen tension (Po2) declines to the point that mitochondrial ATP synthesis becomes limited by oxygen availability. Although this critical Po2 has been determined in animal tissue in vitro and in situ, there remains controversy concerning potential disparities between values measured in vivo and ex vivo. To address this issue, we used concurrent heteronuclear magnetic resonance spectroscopy (MRS) to determine the critical intracellular Po2 in resting human skeletal muscle in vivo. We interleaved measurements of deoxymyoglobin using 1H-MRS with measures of high-energy phosphates and pH using 31P-MRS, during 15 min of ischemia in the tibialis anterior muscles of 6 young men. ATP production and intramyocellular Po2 were quantified throughout ischemia. Critical Po2, determined as the Po2 corresponding to the point where PCr begins to decline (PCrip) in resting muscle during ischemia, was 0.35 ± 0.20 Torr, means ± SD. This in vivo value is consistent with reported values ex vivo and does not support the notion that critical Po2 in resting muscle is higher when measured in vivo. Furthermore, we observed a 4.5-fold range of critical Po2 values among the individuals studied. Regression analyses revealed that time to PCrip was associated with critical Po2 and the rate of myoglobin desaturation ( r = 0.83, P = 0.04) but not the rate of ATP consumption during ischemia. The apparent dissociation between ATP demand and myoglobin deoxygenation during ischemia suggests that some degree of uncoupling between intracellular energetics and oxygenation is a potentially important factor that influences critical Po2 in vivo.

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Development, Pre-clinical Investigation and Histopathological Evaluation of Metronidazole Loaded Topical Formulation for Treatment of Skin Inflammatory disorders

Drug Delivery Letters ◽

10.2174/2210303110999200821123047 ◽

2020 ◽

Vol 10 ◽

Author(s):

Divya Thakur ◽

Gurpreet Kaur ◽

Sheetu Wadhwa ◽

Ashana Puri

Keyword(s):

Ex Vivo ◽

Clinical Investigation ◽

In Vivo Studies ◽

Tween 20 ◽

Inflammatory Disorders ◽

Rat Paw Edema ◽

Ex Vivo Permeation ◽

Permeation Studies ◽

Anti Inflammatory

Background: Metronidazole (MTZ) is an anti-oxidant and anti-inflammatory agent with beneficial therapeutic properties. The hydrophilic nature of molecule limits its penetration across the skin. Existing commercial formulations have limitations of inadequate drug concentration present at target site, which requires frequent administration and poor patient compliance. Objective: The aim of current study was to develop and evaluate water in oil microemulsion of Metronidazole with higher skin retention for treatment of inflammatory skin disorders. Methods: Pseudo ternary phase diagrams were used in order to select the appropriate ratio of surfactant and co-surfactant and identify the microemulsion area. The selected formulation consisted of Capmul MCM as oil, Tween 20 and Span 20 as surfactant and co-surfactant, respectively, and water. The formulation was characterized and evaluated for stability, Ex vivo permeation studies and in vivo anti-inflammatory effect (carrageenan induced rat paw edema, air pouch model), anti-psoriatic activity (mouse-tail test). Results: The particle size analyses revealed average diameter and polydispersity index of selected formulation to be 16 nm and 0.373, respectively. The results of ex vivo permeation studies showed statistically higher mean cumulative amount of MTZ retained in rat skin from microemulsion i.e. 21.90 ± 1.92 μg/cm2 which was 6.65 times higher as compared to Marketed gel (Metrogyl gel®) with 3.29 ± 0.11 μg/cm2 (p<0.05). The results of in vivo studies suggested the microemulsion based formulation of MTZ to be similar in efficacy to Metrogyl gel®. Conclusion: Research suggests efficacy of the developed MTZ loaded microemulsion in treatment of chronic skin inflammatory disorders.

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Global Deletion of 11β-HSD1 Prevents Muscle Wasting Associated with Glucocorticoid Therapy in Polyarthritis

International Journal of Molecular Sciences ◽

10.3390/ijms22157828 ◽

2021 ◽

Vol 22 (15) ◽

pp. 7828

Author(s):

Justine M. Webster ◽

Michael S. Sagmeister ◽

Chloe G. Fenton ◽

Alex P. Seabright ◽

Yu-Chiang Lai ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Skeletal Muscle ◽

Chronic Inflammation ◽

Muscle Atrophy ◽

Muscle Wasting ◽

Ex Vivo ◽

Glucocorticoid Therapy ◽

Knock Out ◽

Fiber Size ◽

Anti Inflammatory

Glucocorticoids provide indispensable anti-inflammatory therapies. However, metabolic adverse effects including muscle wasting restrict their use. The enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11β-HSD1) modulates peripheral glucocorticoid responses through pre-receptor metabolism. This study investigates how 11β-HSD1 influences skeletal muscle responses to glucocorticoid therapy for chronic inflammation. We assessed human skeletal muscle biopsies from patients with rheumatoid arthritis and osteoarthritis for 11β-HSD1 activity ex vivo. Using the TNF-α-transgenic mouse model (TNF-tg) of chronic inflammation, we examined the effects of corticosterone treatment and 11β-HSD1 global knock-out (11βKO) on skeletal muscle, measuring anti-inflammatory gene expression, muscle weights, fiber size distribution, and catabolic pathways. Muscle 11β-HSD1 activity was elevated in patients with rheumatoid arthritis and correlated with inflammation markers. In murine skeletal muscle, glucocorticoid administration suppressed IL6 expression in TNF-tg mice but not in TNF-tg11βKO mice. TNF-tg mice exhibited reductions in muscle weight and fiber size with glucocorticoid therapy. In contrast, TNF-tg11βKO mice were protected against glucocorticoid-induced muscle atrophy. Glucocorticoid-mediated activation of catabolic mediators (FoxO1, Trim63) was also diminished in TNF-tg11βKO compared to TNF-tg mice. In summary, 11β-HSD1 knock-out prevents muscle atrophy associated with glucocorticoid therapy in a model of chronic inflammation. Targeting 11β-HSD1 may offer a strategy to refine the safety of glucocorticoids.

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SAT0315 INHIBITION OF MICROSOMAL PROSTAGLANDIN E SYNTHASE-1 (MPGES-1) BY GS-248 REDUCES PROSTAGLANDIN E2 BIOSYNTHESIS WHILE INCREASING PROSTACYCLIN IN HUMAN SUBJECTS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.5503 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 1103.2-1103

Author(s):

C. Edenius ◽

G. Ekström ◽

J. Kolmert ◽

R. Morgenstern ◽

P. Stenberg ◽

...

Keyword(s):

Whole Blood ◽

Vascular Tone ◽

Ex Vivo ◽

Prostaglandin E ◽

Maximum Plasma ◽

Prostaglandin E Synthase ◽

Cox 2 ◽

Anti Inflammatory ◽

Oral Doses ◽

Microsomal Prostaglandin E Synthase

Background:Microsomal prostaglandin E synthase-1 (mPGES-1) catalyzes the formation prostaglandin (PG) E2from cyclooxygenase derived PGH2(1, 2). Inhibition of mPGES-1 leads to reduction of pro-inflammatory PGE2, while in vessels there is a concomitant increase of vasoprotective prostacyclin (PGI2) via shunting of PGH2(3,4). Apart from relieving symptoms in experimental animal models of inflammation, inhibitors of mPGES-1 cause relaxation of human medium sized arteries(4)and resistance arteries(5). The prostaglandin profile following mPGES-1 inhibition, explains the anti-inflammatory effects and also opens for the possibility of treating inflammatory diseases with concomitant vasculopathies. GS-248 is a potent and selective inhibitor of mPGES-1 exhibiting sub-nanomolar IC50in human whole bloodex vivo.Objectives:To evaluate safety, tolerability, pharmacokinetics and pharmacodynamics of GS-248.Methods:Healthy males and females (age 18–73 years) were included in the study. Six cohorts were administrated single oral doses of 1-300mg GS-248 (n=36) or placebo (n=12), three cohorts were administered once daily doses of 20-180mg GS-248 (n=18) or placebo (n=12) over ten days. In addition, 8 subjects were treated in a separate cohort with 200mg celecoxib bid for ten days. Blood samples were drawn for measurement of GS-248 exposure and production of PGE2after LPS incubationex vivo. The content of PGE2and PGI2metabolites was measured in urine. All analyses were performed by LC-MS/MS.Results:GS-248 was safe and well tolerated at all tested dose levels. Maximum plasma concentration was achieved 1 - 2.5 hours after dosing, and half-life was about 10 hours. Induced PGE2formationex vivo,catalyzed by mPGES-1, was completely inhibited for 24 hours after a single low dose (40mg) of GS-248. In urine, GS-248 dose-dependently reduced the excretion of PGE2metabolite by more than 50% whereas the excretion of PGI2metabolite increased more than twice the baseline levels. In the celecoxib cohort urinary metabolites of both PGE2and PGI2were reduced with approx 50%.Conclusion:GS-248 at investigated oral doses was safe and well tolerated. There was a sustained inhibition of LPS induced PGE2formation in whole blood. In urine, there was a metabolite shift showing reduced PGE2and increased PGI2, while celecoxib reduced both PGE2and PGI2metabolites. This suggests that selective inhibition of mPGES-1 results in systemic shunting of PGH2to PGI2formation, leading to anti-inflammatory and vasodilatory effects, while preventing platelet activation. The results warrant further evaluation of GS-248 in inflammatory conditions with vasculopathies such as Digital Ulcers and Raynaud’s Phenomenon in Systemic Sclerosis.References:[1]Korotkova M, Jakobsson PJ. Persisting eicosanoid pathways in rheumatic diseases. Nat Rev Rheumatol. 2014;10:229-41[2]Bergqvist F, Morgenstern R, Jakobsson PJ. A review on mPGES-1 inhibitors: From preclinical studies to clinical applications. Prostaglandins Other Lipid Mediat. 2019;147:106383[3]Kirkby NS, et al. Mechanistic definition of the cardiovascular mPGES-1/COX-2/ADMA axis. Cardiovasc Res. 2020[4]Ozen G, et al. Inhibition of microsomal PGE synthase-1 reduces human vascular tone by increasing PGI2: a safer alternative to COX-2 inhibition. Br J Pharmacol. 2017;174:4087-98[5]Larsson K, et al. Biological characterization of new inhibitors of microsomal PGE synthase-1 in preclinical models of inflammation and vascular tone. Br J Pharmacol. 2019;176:4625-38Disclosure of Interests:Charlotte Edenius Shareholder of: Gesynta Pharma, Consultant of: Gesynta Pharma,, Gunilla Ekström Shareholder of: Gesynta Pharma, Consultant of: Gesynta Pharma,, Johan Kolmert Consultant of: Gesynta Pharma,, Ralf Morgenstern Shareholder of: Gesynta Pharma, Employee of: Gesynta Pharma, Patric Stenberg Shareholder of: Gesynta Pharma, Employee of: Gesynta Pharma, Per-Johan Jakobsson Shareholder of: Gesynta Pharma, Grant/research support from: Gesynta Pharma, AstraZeneca,, Göran Tornling Shareholder of: Gesynta Pharma, Vicore Pharma,, Consultant of: Gesynta Pharma, Vicore Pharma, AnaMar

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Consequences of SUR2[A478V] Mutation in Skeletal Muscle of Murine Model of Cantu Syndrome

Cells ◽

10.3390/cells10071791 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1791

Author(s):

Rosa Scala ◽

Fatima Maqoud ◽

Nicola Zizzo ◽

Giuseppe Passantino ◽

Antonietta Mele ◽

...

Keyword(s):

Skeletal Muscle ◽

Katp Channel ◽

Ex Vivo ◽

Channel Modulation ◽

Flexor Digitorum Brevis ◽

Inflammatory Edema ◽

Flexor Digitorum ◽

Channel Currents

(1) Background: Cantu syndrome (CS) arises from gain-of-function (GOF) mutations in the ABCC9 and KCNJ8 genes, which encode ATP-sensitive K+ (KATP) channel subunits SUR2 and Kir6.1, respectively. Most CS patients have mutations in SUR2, the major component of skeletal muscle KATP, but the consequences of SUR2 GOF in skeletal muscle are unknown. (2) Methods: We performed in vivo and ex vivo characterization of skeletal muscle in heterozygous SUR2[A478V] (SUR2wt/AV) and homozygous SUR2[A478V] (SUR2AV/AV) CS mice. (3) Results: In SUR2wt/AV and SUR2AV/AV mice, forelimb strength and diaphragm amplitude movement were reduced; muscle echodensity was enhanced. KATP channel currents recorded in Flexor digitorum brevis fibers showed reduced MgATP-sensitivity in SUR2wt/AV, dramatically so in SUR2AV/AV mice; IC50 for MgATP inhibition of KATP currents were 1.9 ± 0.5 × 10−5 M in SUR2wt/AV and 8.6 ± 0.4 × 10−6 M in WT mice and was not measurable in SUR2AV/AV. A slight rightward shift of sensitivity to inhibition by glibenclamide was detected in SUR2AV/AV mice. Histopathological and qPCR analysis revealed atrophy of soleus and tibialis anterior muscles and up-regulation of atrogin-1 and MuRF1 mRNA in CS mice. (4) Conclusions: SUR2[A478V] “knock-in” mutation in mice impairs KATP channel modulation by MgATP, markedly so in SUR2AV/AV, with atrophy and non-inflammatory edema in different skeletal muscle phenotypes.

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AB0069 LORECIVIVINT (SM04690), AN INTRA-ARTICULAR, SMALL-MOLECULE CLK/DYRK1A INHIBITOR THAT MODULATES THE WNT PATHWAY, AS A POTENTIAL TREATMENT FOR MENISCAL INJURIES

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.6454 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 1335.2-1335

Author(s):

T. Seo ◽

V. Deshmukh ◽

Y. Yazici

Keyword(s):

Small Molecule ◽

Rat Model ◽

Wnt Pathway ◽

Ex Vivo ◽

Meniscal Tear ◽

Knee Oa ◽

Meniscus Degeneration ◽

Anti Inflammatory ◽

Meniscal Damage

Background:Meniscal injuries, associated with pain, stiffness, and localized swelling, are the most common pathology of the knee with a prevalence of 61 per 100,000.1Meniscal damage is a frequent finding on MRI images of knee osteoarthritis (OA)2; while a meniscal tear can lead to knee OA, knee OA can also lead to a spontaneous meniscal tear.3Efforts to repair meniscal damage have been largely unsuccessful and do not prevent the progression of degenerative changes that lead to knee OA.4The Wnt signaling pathway has been shown to be regulated during meniscal development,5,6suggesting that manipulation of this pathway may influence the regenerative capacity of the meniscus. Lorecivivint (LOR; SM04690) is an intra-articular (IA), small-molecule CLK/DYRK1A inhibitor that modulates the Wnt pathway.Objectives:LOR was evaluated in preclinical studies to determine its protective and anabolic effects in ex vivo explants and in a rat model of chemically induced inflammatory meniscus degeneration.Methods:Effects of LOR (30 nM) on expression of matrix metalloproteinases (MMPs) in cultured rat menisci treated with IL-1B were measured by qPCR. In vivo, LOR activity was evaluated in a rat model of monosodium iodoacetate (MIA) injection-induced inflammatory meniscus degeneration. A single IA injection of MIA was immediately followed by a single IA injection of LOR (0.3 ug) or vehicle. Knees were harvested on Days 1, 4, and 11 and menisci were isolated. Anti-inflammatory effects were evaluated by measuringTNFAandIL6expression by qPCR. Meniscus protection was evaluated by qPCR for MMPs and aggrecanase and anabolic effects by qPCR for collagens.Results:In ex vivo meniscal explants, LOR inhibited expression ofMMP1,MMP3, andMMP13compared to DMSO (P<0.01). In vivo, LOR significantly decreased expression of these MMPs and aggrecanase (P<0.05) compared to vehicle in the rat model of inflammatory meniscus degeneration at Day 4 after MIA injection. In addition, LOR reduced expression of inflammatory cytokinesTNFAandIL6at Day 4 compared to vehicle. Finally, LOR increased expression of collagen types I, II, and III at Day 11 after MIA injection.Conclusion:LOR exhibited protective effects in the meniscus ex vivo and in vivo by reducing the expression of catabolic enzymes compared to control. Anti-inflammatory effects of LOR were demonstrated by inhibition of inflammatory cytokine expression. Compared to vehicle, LOR increased expression of collagens in vivo, indicating potential meniscal anabolic effects. These data support further investigation of LOR as a potential disease-modifying therapy for meniscal injuries.References:[1]Logerstedt D and Snyder-Mackler L.J Orthop Sports Phys Ther. 2010[2]Englund M, et al.Rheum Dis Clin North Am. 2009[3]Englund M, et al.Radiol Clin North Am. 2009[4]von Lewinski, et al.Knee Surg Sports Traumatol Arthrosc. 2007[5]Pazin DE, et al.ORS 2012 Annual Meeting. Paper No. 0221[6]Pazin DE, et al.Dev Dyn. 2012Disclosure of Interests:Tim Seo Shareholder of: Samumed, LLC, Employee of: Samumed, LLC, Vishal Deshmukh Shareholder of: Samumed, LLC, Employee of: Samumed, LLC, Yusuf Yazici Shareholder of: Samumed, LLC, Grant/research support from: Bristol-Myers Squibb, Celgene, and Genentech, Consultant of: Celgene and Sanofi, Employee of: Samumed, LLC

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