P832LDL-C levels on statins and cardiovascular event risk in stable coronary artery disease: An observation from the REAL-CAD study

Background

The relation between very low on-treatment low-density lipoprotein cholesterol (LDL-C) level and the cardiovascular event risk is still unclear in patients receiving the same doses of statins.

Methods

From the REAL-CAD study comparing high-dose with low-dose pitavastatin therapy in Japanese patients with stable coronary artery disease, 11105 patients without reported non-adherence for the study drug were divided into 3 groups according to the on-treatment LDL-C level at 6-month (<70 mg/dL, 70–100 mg/dL, and ≥100 mg/dL; N=1016, N=3078, and N=1665 in the pitavastatin 1 mg/day stratum; N=2431, N=2524, and N=391 in the pitavastatin 4 mg/day stratum). Primary outcome measure was a composite of cardiovascular death, non-fatal myocardial infarction, non-fatal ischemic stroke, or unstable angina requiring emergent admission.

Results

In the pitavastatin 1 mg/day stratum, cumulative 4-year incidence of the primary outcome measure was not significantly different across the 3 groups (5.0%, 5.7%, and 5.2%, P=0.51), while in the 4 mg/day stratum, it was significantly higher in the LDL-C ≥100 mg/dL group than in other groups (4.5%, 3.4%, and 9.1%, P<0.001). The adjusted risks of the LDL-C <70 mg/dL group relative to the LDL-C 70–100 mg/dL group (reference) remained insignificant for the primary outcome measure in both 1 mg/day and 4 mg/day strata (HR 0.84, 95% CI 0.58–1.18, P=0.32, and HR 1.25, 95% CI 0.88–1.79, P=0.22). The adjusted risk of LDL-C ≥100 mg/dL group relative to the reference group was not significant for the primary outcome measure in the 1 mg/day stratum (HR 0.82, 95% CI 0.60–1.11, P=0.21), while it was highly significant in the 4 mg/day stratum (HR 3.32, 95% CI 2.08–5.17, P<0.001). In the on-treatment LDL-C ≥100 mg/dL group in the 4 mg/day stratum, LDL-C increased by 6.3 mg/dL from baseline to 6-month despite dose escalation of pitavastatin from 1 mg/day to 4 mg/day, suggesting the presence of unreported poor adherence in this small subgroup.

Adjusted Effects of On-treatment LDL-C

Conclusions

Very low on-treatment LDL-C level (<70 mg/dL) was not associated with lower cardiovascular event risk compared with moderately low on-treatment LDL-C level (70–100 mg/dL) in patients receiving the same doses of statins. Too much emphasis on the target LDL-C strategy might mislead the clinical practice.

Acknowledgement/Funding

The Comprehensive Support Project for Clinical Research of Lifestyle-Related Disease of the Public Health Research Foundation.

P5600Surgical reconstruction of type A aortic dissection in octogenarians

Introduction

Because the population is aging, the indication for surgical reconstruction in older patients will increase. Japan is especially facing the most aging society worldwide. However, surgical reconstruction of type A aortic dissection (AADA) in patients who are octogenarians is not often performed because of the decision of the patient or surgeon. We examined the outcome of surgical reconstruction of AADA in octogenarians.

Method

Over 4 years, 132 cases of surgical reconstruction of AADA were analyzed. Twenty-five consecutive octogenarians with AADA were retrospectively reviewed. In our institution, we recommend an emergent operation to the patient or family in all generations unless they reject it for some reason.

Results

Operative factors in octogenarians with AADA were not significantly different compared with those in patients aged younger than 79 years (n=107) (operation: 238±11 vs. 246±5 min, p=0.54; cardiopulmonary bypass: 147±7.4 vs. 154±3.5 min, p=0.42; aortic-clamp: 114±6.0 vs. 120±2.8 min, p=0.36; hypothermic-arrest: 43±2.7 vs. 42±1.3 min, p=0.81). The overall mortality rate was 24.0% (n=6). The mortality rate was no difference between younger patients and octogenarians (OR: 2.7, 95% CI: 0.86–8.21, p=0.08). Furthermore, MACE (Major Adverse Cardiac Event) and the postoperative stroke rate were not significantly different between the two groups (OR: 1.5, 95% CI: 0.52–3.93, p=0.42; OR: 0.77, 95% CI: 0.16–2.59, p=0.69, respectively).

Conclusion

In AADA, the outcome of emergent surgical reconstruction in octogenarians is acceptable. Even with the risk of aging, surgeons should consider aggressive surgical reconstruction in octogenarians.

P4731Procedure-related acute thrombosis after surgical left atrial appendage occlusion for atrial fibrillation

Background/Introduction

Left atrial appendage (LAA) occlusion is an effective strategy for thromboembolism prevention in patients with atrial fibrillation (AF), and the novel methods of occlusion is various. The acute thrombosis after percutaneous LAA occlusion devices has been recently reported, but thrombus formation after surgical LAA occlusion is still unclear.

Purpose

This study aimed to analyse the incidence and prognosis of thrombus formation on closure stump line in patients with AF who underwent surgical LAA occlusion.

Methods

This study retrospectively analised the data from patients treated with two methods of surgical LAA closure, resection or clipping, from January 2014 to November 2018.

Results

A total of 187 consecutive patients with AF underwent surgical LAA closure (31 clipping and 156 stapler resection). 170 patients (91%) underwent cardiac CT for LAA imaging on postoperative day 2. The incidence of acute procedure-related thrombus formation in full cohort was 19% (35 cases). The incidence of acute thrombus in patients with clipping and resection was 19% and 16%, respectively (Fisher's exact test, p=0.8). All of 35 patients who had thrombus on LAA closure stump line underwent cardiac CT again 3 months after the primary CT. In all patients with secondary cardiac CT, thrombus on LAA closure stump line disappeared. No symptomatic thromboembolism occurred during the follow-up from operation to secondary CT scan.

Conclusion(s)

Thrombus formation on stump after surgical LAA closure may often occur on acute phase. The optimal LAA imaging and anti-coagulation therapy after surgical LAA occlusion will prevent patients with acute thrombus from thromboembolism.

P1831Prediction of cardiovascular events by atheromatous plaques detected by non-obstructive general angioscopy: two-year results of EAST-NOGA Registry

Background

Non-obstructive general angioscopy (NOGA) has revealed the intimal damages or atheromatous plaques as well as its spontaneous rupture of the aorta. Recent study revealed that plaque debris or different size of cholesterol crystals were detected in the blood above the spontaneous ruptured aortic plaque observed by NOGA and these plaque materials might cause the peripheral organ damages as the embolic source. These various morphological changes may cause the acute aortic events or atheroembolic events on the peripheral organs, such as brain, kidney, peripheral artery and so on.

Purpose

EAST-NOGA (Evaluation of AtheroSclerotic and rupture events by Non-Obstructive General Angioscopy) is a multi-center prospective observational study to assess the relationship between the findings of NOGA and future cardiovascular events.

Methods

Five hundred and seventy-seven patients with atherosclerotic cardiovascular disease who underwent NOGA study. The major cerebrocardiovascular events including cardiovascular death, non-fatal myocardial infarction, non-fatal cerebral infarction, and acute aortic syndrome were accumulated during the 2-year follow-up after NOGA study.

Results

The median number of aortic atheromatous plaques was 6 [IQR: 3–12]. A total of 514 patients were followed up (89.1%). The mean follow-up duration was 757±120 days. Major adverse cardiovascular events developed in 23 (4.5%) during 2 years follow-up. Patients with MACE and cerebral infarction, had significantly greater number of aortic atheromatous plaques (11 [5–19] vs. 6 [3–11], p<0.001, 12 [4–20] vs. 6 [3–12], p=0.014, respectively). In a univariate analysis, the number of aortic atheromatous plaques and ruptured plaque were significant predictors of MACE (HR: 1.09 95% confidence interval 1.05–1.14, p<0.001) and (HR: 1.12, 95% confidence interval 1.02–1.23, p=0.02). In a multivariate logistic analysis, the number of aortic atheromatous plaques is one of the independent predictors of MACE (HR 1.05, 95% confidence interval 1.00–1.10, p=0.032).

Conclusion

The number of atheromatous plaques identified by NOGA has a significant relation to the onset of cerebral infarction, which suggest the atheromatous plaque were vulnerable and ruptured spontaneously, then cause the aortogenic cerebral infarction. The NOGA study would be useful for predicting the futured atheroembolic events.

Acknowledgement/Funding

None

[Acute myeloid leukemia with sudden onset bilateral lower extremity paralysis caused by disseminated mucormycosis following unrelated bone marrow transplantation]

A 63-year-old woman was admitted to our hospital with relapsed acute myeloid leukemia. On day10 after reinduction therapy, she became febrile. Computed tomography on day15 revealed right upper lobe consolidation. Because the β-D glucan and Aspergillus galactomannan antigen tests were negative, we considered pulmonary mucormycosis as a breakthrough infection under voriconazole administration. Liposomal amphotericin B was initiated, and the patient underwent unrelated bone marrow transplantation although not in complete remission. She developed right shoulder pain on day1, and her pneumonia worsened on day3. She reported right lower extremity paralysis on day15, and developed bilateral lower extremity motor and sensory paralysis the next day. T2-enhanced magnetic resonance imaging revealed hyperdense lesions in the spinal cord at Th11. Transverse myelitis was diagnosed, and she underwent antiviral therapy. After engraftment, she died of pneumonia on day24. Postmortem examination revealed disseminated mucormycosis involving the lungs, liver, diaphragm, blood vessels, and dura matter of the spinal cord; it also revealed that the sudden bilateral lower extremity paralysis was caused by disseminated mucormycosis. This case stresses the possibility of mucormycosis, particularly in prolonged neutropenic patients with pain, fever, and focal neurological findings.

Recurrent Aphthous Stomatitis Caused by Cytomegalovirus, Herpes Simplex Virus, and Candida Species in a Kidney Transplant Recipient: A Case Report

Recipients of organ transplants are immunosuppressed and at high risk of oral infection. Oral diseases are often neglected compared with infections of other organs that typically confer higher morbidity. However, severe local symptoms hinder oral intake, decrease quality of life, and are sometimes lethal. Here we describe a case of a 57-year-old woman who developed recurrent aphthous stomatitis after kidney transplantation; the cause of the infection was complex and included cytomegalovirus, herpes simplex virus, and Candida species. Since misdiagnosis of oral diseases impairs patient quality of life and increases morbidity, clinicians should be aware of possible etiologies of oral infections in renal transplant recipients.

Effective multiple sideband generation using an electro-optic modulator for a multiple isotope magneto-optical trap

Herein, we report an effective method for the generation of radio-frequency (RF) sidebands in an electro-optic modulator for the simultaneous magneto-optical trapping of two isotopes. This is achieved by switching the RF signals alternately, which suppresses the generation of unwanted frequency signals and improves the laser power per sideband. The generated sidebands are successfully applied to a dual-rubidium-isotope magneto-optical trap (MOT), which results in an increased number of trapped atoms. This simple, flexible, and robust technique can be implemented in experiments that require a large number of atoms in multiple-isotope MOTs and for various applications.

Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2×10^{21} Protons on Target

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×10^{20} protons on target in the neutrino (antineutrino) mode, 89 ν_{e} candidates and seven anti-ν_{e} candidates are observed, while 67.5 and 9.0 are expected for δ_{CP}=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δ_{CP}, does not include the CP-conserving cases (δ_{CP}=0, π). The best-fit values of other parameters are sin^{2}θ_{23}=0.526_{-0.036}^{+0.032} and Δm_{32}^{2}=2.463_{-0.070}^{+0.071}×10^{-3}  eV^{2}/c^{4}.

Thermal behavior, structure, dynamic properties of aqueous glycine solutions confined in mesoporous silica MCM-41 investigated by x-ray diffraction and quasi-elastic neutron scattering

Differential scanning calorimetry, X-ray diffraction, and quasi-elastic neutron scattering (QENS) measurements of aqueous glycine solutions confined in mesoporous silica (MCM-41) were performed at different glycine concentrations, pH, and loading ratio (=mass of glycine solution/mass of dry MCM-41) in the temperature range from 305 to 180 K to discuss the confinement effect on the thermal behavior, the structure, and the dynamic properties of the solutions. The freezing points of the confined glycine solutions decreased, compared with those of the bulk solutions. The corresponding exothermic peak due to ice formation became broader with an increase in the glycine concentration. By subtracting X-ray diffraction patterns of dry MCM-41 from those of glycine solution-loaded MCM-41, information about the structure of the confined glycine solutions was obtained. The radial distribution functions of the confined glycine solutions showed that the peaks assigned to the interaction between glycine molecules and the surface silanol (Si-OH) groups of MCM-41 at pH = 5 were observed, in contrast to the case at pH = 2. The QENS data on H/D substituted aqueous glycine solutions gave the translational diffusion coefficients and the residence time of glycine and water molecules confined in MCM-41 individually. The activation energy of the diffusion coefficient of a glycine molecule at pH = 5 was larger than that at pH = 2. These results imply that glycine molecules locate near the pore surface of MCM-41 due to the formation of hydrogen bonding between glycine molecules and the silanol group of the MCM-41 wall at pH = 5.

Response of epithelial cells infected by Treponema denticola

OBJECTIVE

In the gingival crevice, the interaction between epithelial cells and periodontopathic bacteria is important for the development of periodontitis. Treponema denticola is a major pathogen of chronic periodontitis and possesses several virulence factors, such as major surface protein (Msp) and prolyl-phenylalanine-specific protease (dentilisin). Here, we investigated the behaviours of epithelial cells infected with T. denticola by measuring the expression of interleukin (IL)-1β, IL-6, β defensin 2 (BD-2) and heat-shock protein 70 (HSP70).

METHODS

Epithelial cells were infected with T. denticola wild-type strain, Msp-deficient mutant or dentilisin-deficient mutant, and the expression levels of the above targets were analysed by polymerase chain reaction.

RESULTS

Infection with T. denticola wild-type strain and mutants induced the production of IL-6 and HSP70. The level of BD-2 induced by T. denticola wild-type strain at 24 hr was significantly higher than that of the dentilisin-deficient mutant. The level of IL-1β mRNA in the wild-type strain and dentilisin-deficient mutant was slightly lower than that in the uninfected control.

CONCLUSION

These results suggest that the levels of BD-2 were affected by Msp and dentilisin. This effect may contribute to the disruption of the response of epithelial cells to eradicate T. denticola.

Effect of combined bifidobacteria supplementation and resistance training on cognitive function, body composition and bowel habits of healthy elderly subjects

Physical exercise exerts favourable effects on brain health and quality of life of the elderly; some of these positive health effects are induced by the modulation of microbiota composition. We therefore conducted a randomised, double blind, placebo-controlled trial that assessed whether a combination of Bifidobacterium spp. supplementation and moderate resistance training improved the cognitive function and other health-related parameters in healthy elderly subjects. Over a 12-week period, 38 participants (66-78 years) underwent resistance training and were assigned to the probiotic Bifidobacterium supplementation (n=20; 1.25×10¹⁰ cfu each of Bifidobacterium longum subsp. longum BB536, B. longum subsp. infantis M-63, Bifidobacterium breve M-16V and B. breve B-3) or the placebo (n=18) group. At baseline and at 12 weeks, we assessed the cognitive function, using the Japanese version of the Montreal Cognitive Assessment instrument (MoCA-J); modified flanker task scores; depression-anxiety scores; body composition; and bowel habits. At 12 weeks, the MoCA-J scores showed a significant increase in both the groups, while the flanker task scores of the probiotic group increased more significantly than those of the placebo group (0.35±0.9 vs -0.29±1.1, P=0.056). Only the probiotic group showed a significant decrease in the depression-anxiety scores (5.2±6.3 to 3.4±5.5, P=0.012) and body mass index (24.0±2.8 to 23.5±2.8 kg/m², P<0.001), with a significant increase in the defecation frequency (5.3±2.3 to 6.4±2.3 times/5 days, P=0.023) at 12 weeks. Thus, in healthy elderly subjects, combined probiotic bifidobacteria supplementation and moderate resistance training may improve the mental condition, body weight and bowel movement frequency.

Selective release of miRNAs via extracellular vesicles is associated with house-dust mite allergen-induced airway inflammation

BACKGROUND

MicroRNAs (miRNAs) may facilitate cell-to-cell communication via extracellular vesicles (EVs). The biological roles of miRNAs in EVs on allergic airway inflammation are unclear.

METHODS

Airway-secreted EVs (AEVs) were isolated from bronchoalveolar lavage fluid (BALF) of control and house-dust mite (HDM) allergen-exposed HDM-sensitized mice. The expression of miRNAs in AEVs or miRNAs and mRNAs in lung tissue was analysed using miRNA microarray.

RESULTS

The amount of AEV increased 8.9-fold in BALF from HDM-exposed mice compared with that from sham-control mice. HDM exposure resulted in significant changes in the expression of 139 miRNAs in EVs and 175 miRNAs in lung tissues, with 54 miRNAs being common in both samples. Expression changes of these 54 miRNAs between miRNAs in AEVs and lung tissues after HDM exposure were inversely correlated. Computational analysis revealed that 31 genes, including IL-13 and IL-5Ra, are putative targets of the miRNAs up-regulated in AEVs but down-regulated in lung tissues after HDM exposure. The amount of AEV in BALF after HDM exposure was diminished by treatment with the sphingomyelinase inhibitor GW4869. The treatment with GW4869 also decreased Th2 cytokines and eosinophil counts in BALFs and reduced eosinophil accumulation in airway walls and mucosa.

CONCLUSION

These results indicate that selective sorting of miRNA including Th2 inhibitory miRNAs into AEVs and increase release to the airway after HDM exposure would be involved in the pathogenesis of allergic airway inflammation.

Antithrombotic Mechanisms of Urokinase lmmobilized Polyurethane

Urokinase immobilized polymer is highly antithrombotic, which cannot be explained only by fibrinolysis. We immobllized 10 IU/cm2 of urokinase to polyurethane by using maleic anhydride methylvinyl ether copolymer as a carrier. Then we incubated blood in circular tubes made of this material, measured the clotting factors and observed the surface of the tubes after incubation by scanning electronmicroscopy and immunofluorescence microscopy. After 5 min incubation, the relative activities of factors V, VIII, IX, X and XII, fibrinogeil, plasminogen and α2 plasmin inhibitor decreased, but the activity of factor VII increased. No platelet adhesion to the surface of the urokinase immobilized polyurethane was observed and there was no significant adsorption of serum proteins, including fibrinogen, fibronectin and vWF antigen, or the surface. Urokinase-immobilized polyurethane catalyzed the digestion of clotting factors as well as fibrinolysis and also inhibited platelet adhesion on its surface probably by inhibiting protein adsorption and its clinical application including vessel prosthesis should be developed further.

Sagittal Magnetic Resonance Imaging of Dysthyroid Ophthalmopathy

Sagittal magnetic resonance imaging (MRI) scans of the eye and orbit were made of 30 eyes in 15 cases of dysthyroid ophthalmopathy (DO). On the basis of these scans, we sought to elucidate relationships between the morphological condition of the levator palpebrae muscle, fatty tissue in the upper eyelid and the superior, inferior recti muscles and the occurrence of such symptoms as lid retraction, lid swelling and vertical disturbance of eye movement. The levator palpebrae muscle was enlarged in all 15 DO eyes (100%) with upper eyelid retraction. In 16 (88.9%) of 18 eyes with apparent lid swelling, enlargement of the preaponeurotic fat or submuscular fat pad was clearly evident. In the control eyes, no such enlargement was seen in either the levator palpebrae muscle or orbital fatty tissue. The clear space between the superior recti and the levator palpebrae muscles that was seen in control eyes was absent in all five eyes that presented a disturbance in infraduction. In 8 (80%) of 10 eyes with a disturbance in supraduction, the inferior rectus muscle was enlarged and muscle extension was impaired. Sagittal MRI seemed to be a useful means of obtaining a better clinical understanding of a variety of eye symptoms associated with DO.

Preliminary Experimental Study about the Feasibility of Combining Pulsatile Cardiopulmonary Support System and a Membrane Oxygenator

A cardiopulmonary support (CPS) device that incorporated a pneumatic ventricular assist device (VAD) and a membrane oxygenator was developed for the support of patients with profound heart and/or respiratory failure. This device has an advantage of being both a pulsatile assist device and membrane oxygenator. A “triple flow” regulator was included in this system to control the blood flow through the oxygenator. The purpose of this study was to clarify the efficacy of this system in supporting an animal model with combined cardiac and respiratory failure. In vitro tests showed 3.7 L/min of pump flow under 1.6 L/min of oxygen supply to the oxygenator even though there was a 50% clamp of a “triple flow” regulator with sufficient pulsatility. In 14 acute canine experiments, cardiogenic shock and acute respiratory failure were introduced by coronary ligation and mechanical hypoventilation simultaneously. The pump flow was maintaned at 1.95 - 0.6 L/min (average 1.2 L/min) and the driving pressure of the pump was controlled between 200 and 300 mmHg positive pressure and -20 to -50 mmHg negative pressure. The driving rate was fixed at 100 bpm and systolic/diastolic ratio was controlled between 35-50%. The canines were divided into control group (n=4) and pumped group (drained from the right atrium n=7, drained from the left atrium n=3). By using CPS system, flow and aortic pressure recovered to the initial baseline level. Without this support, the canine model could not maintain systemic circulation. In the group drained from right atrium, central venous pressure decreased with the device from 13.9 ± 2.4 to 5.6 ± 1.4 cm H2O (p<0.01), returned to the initial level without this device (p<0.01). In the group drained from left atrium, pulmonary capillary wedge pressure decreased from 37.9 ± 4.6 to 20.8 ± 5.7 mmHg (p<0.01), and returned to the initial level without the device, arterial oxygen tension levels increased (p<0.01), and also arterial oxygen saturation levels recovered (p<0.01). The results suggest that the current model of the pulsatile CPS has a potential to support the animal model with combined cardiac and respiratory failure.

A genome-wide association study identifies two novel susceptibility loci and trans population polygenicity associated with bipolar disorder

Genome-wide association studies (GWASs) have identified several susceptibility loci for bipolar disorder (BD) and shown that the genetic architecture of BD can be explained by polygenicity, with numerous variants contributing to BD. In the present GWAS (Phase I/II), which included 2964 BD and 61 887 control subjects from the Japanese population, we detected a novel susceptibility locus at 11q12.2 (rs28456, P=6.4 × 10-9), a region known to contain regulatory genes for plasma lipid levels (FADS1/2/3). A subsequent meta-analysis of Phase I/II and the Psychiatric GWAS Consortium for BD (PGC-BD) identified another novel BD gene, NFIX (Pbest=5.8 × 10-10), and supported three regions previously implicated in BD susceptibility: MAD1L1 (Pbest=1.9 × 10-9), TRANK1 (Pbest=2.1 × 10-9) and ODZ4 (Pbest=3.3 × 10-9). Polygenicity of BD within Japanese and trans-European-Japanese populations was assessed with risk profile score analysis. We detected higher scores in BD cases both within (Phase I/II) and across populations (Phase I/II and PGC-BD). These were defined by (1) Phase II as discovery and Phase I as target, or vice versa (for 'within Japanese comparisons', Pbest~10-29, R2~2%), and (2) European PGC-BD as discovery and Japanese BD (Phase I/II) as target (for 'trans-European-Japanese comparison,' Pbest~10-13, R2~0.27%). This 'trans population' effect was supported by estimation of the genetic correlation using the effect size based on each population (liability estimates~0.7). These results indicate that (1) two novel and three previously implicated loci are significantly associated with BD and that (2) BD 'risk' effect are shared between Japanese and European populations.

Chemokine (C-X-C motif) ligand 1 is a myokine induced by palmitate and is required for myogenesis in mouse satellite cells

AIM

The functional significance of the myokines, cytokines and peptides produced and released by muscle cells has not been fully elucidated. The purpose of this study was to identify a myokine with increased secretion levels in muscle cells due to saturated fatty acids and to examine the role of the identified myokine in the regulation of myogenesis.

METHODS

Human primary myotubes and mouse C2C12 myotubes were used to identify the myokine; its secretion was stimulated by palmitate loading. The role of the identified myokine in the regulation of the activation, proliferation, differentiation and self-renewal was examined in mouse satellite cells (skeletal muscle stem cells).

RESULTS

Palmitate loading promoted the secretion of chemokine (C-X-C motif) ligand 1 (CXCL1) in human primary myotubes, and it also increased CXCL1 gene expression level in C2C12 myotubes in a dose- and time-dependent manner. Palmitate loading increased the production of reactive oxygen species along with the activation of nuclear factor-kappa B (NF-κB) signalling. Pharmacological inhibition of NF-κB signalling attenuated the increase in CXCL1 gene expression induced by palmitate and hydrogen peroxide. Palmitate loading significantly increased CXC receptor 2 gene expression in undifferentiated cells. CXCL1 knockdown attenuated proliferation and myotube formation by satellite cells, with reduced self-renewal. CXCL1 knockdown also significantly decreased the Notch intracellular domain protein level.

CONCLUSION

These results suggest that secretion of the myokine CXCL1 is stimulated by saturated fatty acids and that CXCL1 promotes myogenesis from satellite cells to maintain skeletal muscle homeostasis.