Evaluation of microembolic signals on carotid ultrasound during pulmonary vein isolation with high-power short-duration and cryoballoon ablations: When and where do bubble and solid emboli arise?

INTRODUCTION: The underlying risks of asymptomatic embolization during high-power short-duration (HPSD) ablation for atrial fibrillation remain unclear. We aimed to evaluate microembolic signals (MESs) during HPSD ablation with power settings of 50 and 90 W in comparison with those during cryoballoon (CB) ablation using a novel carotid ultrasound-Doppler system that classifies solid and air bubble signals using real-time monitoring. METHODS AND RESULTS: Forty-seven patients underwent HPSD ablation using radiofrequency (RF), and 13 underwent CB ablation. MESs were evaluated using a novel pastable soft ultrasound probe equipped with a carotid ultrasound during pulmonary vein isolation. We compared the detailed MESs and their timing between RF and CB ablations. The number of MESs and solid signals were significantly higher in the RF group than in CB group (209 ± 229 vs. 79 ± 32, p = .047, and 83 ± 89 vs. 28 ± 17, p = .032, respectively). In RF ablation, the number of MESs, solid, and bubble signals per ablation point, or per second, was significantly higher at 90 W than at 50 W ablation. The MESs, solid, and bubble signals were detected more frequently in the bottom and anterior walls of the left pulmonary vein (LPV) ablation. In contrast, many MESs were observed before the first CB application and decreased chronologically as the procedure progressed. Signals were more prevalent during the CB interval rather than during the freezing time. Among the 28 patients, 4 exhibited a high-intensity area on postbrain magnetic resonance imaging (MRI). The MRI-positive group showed a trend of larger signal sizes than did the MRI-negative group. CONCLUSION: The number of MESs was higher in the HPSD RF group than in the CB group, with this risk being more pronounced in the 90 W ablation group. The primary detection site was the anterior wall of the LPV in RF and the first interval in CB ablation.

High Efficacy and Safety of Asciminib in a Chronic Myeloid Leukemia Patient with Chronic Kidney Disease Following Renal Transplantation.

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm driven by the BCR::ABL1 tyrosine kinase. Tyrosine kinase inhibitors (TKIs) have been established as standard therapies for CML. However, some CML patients experience TKI intolerance. Asciminib was approved for CML patients either intolerant or refractory to TKI therapy. We herein report a 63-year-old CML patient who underwent renal transplantation and exhibited TKI intolerance. He was switched to asciminib, which achieved a deep molecular response without exacerbation of the renal function. Our experience revealed that asciminib is effective and safe for CML patients complicated with chronic kidney disease.

Clinical Outcomes and Predictors of All-Cause Mortality After Complex High-Risk and Indicated Revascularization Using Percutaneous Coronary Intervention.

The concept of complex and high-risk indicated procedures using percutaneous coronary intervention (CHIP-PCI) has recently been defined. However, few studies have investigated the prognosis of patients after CHIP-PCI. We enrolled 322 consecutive patients who underwent CHIP-PCI. CHIP-PCI was defined as a procedure satisfying at least one criterion each for both patient and procedure characteristics, as follows: patient characteristics [age ≥ 75 years old, low left ventricular ejection fraction (LVEF), diabetes mellitus, acute coronary syndrome, previous coronary artery bypass surgery, peripheral arterial disease, severe chronic kidney disease (CKD), chronic obstructive pulmonary disease (COPD), and severe valvular disease] and procedure characteristics [unprotected left main disease, degenerated saphenous or radial artery grafts, severely calcified lesions, last patent conduit, chronic total occlusions, multivessel disease, and use of mechanical circulatory support]. On Kaplan-Meier analysis, 1-, 2-, and 3-year survival rates following CHIP-PCI was 93.8%, 89.2%, and 85.4%, respectively. Moreover, on Cox multivariate hazard analysis, age (≥ 75 years old) (hazard ratio: 4.01, 95% confidence interval: 1.92-8.38, P < 0.01), COPD (hazard ratio: 2.95, 95% confidence interval: 1.38-6.32, P < 0.01), low LVEF (hazard ratio: 3.35, 95% confidence interval: 1.55-7.22, P < 0.01), severe CKD (hazard ratio: 3.02, 95% confidence interval: 1.44-6.36, P < 0.01), and use of mechanical circulatory support (hazard ratio: 5.97, 95% confidence interval: 2.72-13.10, P < 0.01) remained significant predictors of mortality. In conclusion, we revealed the clinical outcomes after CHIP-PCI. The presence of advanced age, COPD, low LVEF, severe CKD, and mechanical circulatory support use might lead to worse clinical outcomes.

Evaluation of the direction and extent of ice formation during cryoballoon ablation: an experimental study.

BACKGROUND: The distal hemisphere of a balloon is generally cooled during cryoapplication. However, a wide ablation area can be acquired after cryoballoon ablation. This study aimed to evaluate the extent of ice formation on two types of balloon surfaces through experimental and simulation studies. METHODS: A standard cryoballoon (SCB; Arctic Front Advance Pro, Medtronic) and novel cryoballoon (NCB; POLARx, Boston Scientific) were frozen for 240 s in 36 °C normal saline solution to observe ice formation on the balloon surface. Pieces of porcine tissue were placed between the upper and lower sides of the balloon, and the balloon was frozen in the horizontal direction for 240 s in 20 attempts (10 for SCB and NCB each). The measured areas of ice formation were evaluated and compared between the upper and lower sides of each balloon. RESULTS: Ice formation was greater on the lower side of the balloon than on the upper side. A larger area of ice formation in the tissue slab was observed on the lower side than on the upper side in both balloons, and the ice formation extended to the proximal hemisphere on the lower side of the balloon. The ice formation area in the NCB was significantly larger than that in SCB. CONCLUSIONS: Ice formation was significantly greater on the lower side of the cryoballoon than on the upper side and extended to the proximal hemisphere of the balloon, which might facilitate the acquisition of a wide ablation area on the left atrial posterior wall after cryoballoon ablation. Different ice formation after cryoballoon ablation Greater ice formation on the lower side of cryoballoon and an extensive ice formation in the proximal hemisphere, especially in novel cryoballoon.

Usefulness of the Snare Technique During Leadless Pacemaker Implantation for a Patient with a Severely Dilated Right Atrium.

We report here the case of a 92-year-old woman with atrial fibrillation bradycardia in which leadless pacemaker implantation was performed with a difficult delivery of the catheter sheath due to an extremely large right atrium. Using a snare technique with correction of the direction of the force on the catheter toward the right ventricle (RV) can result in successful delivery of the pacemaker catheter and stable placement of the pacemaker system in the RV septum. This specific snare technique has the potential to facilitate leadless pacemaker implantation safely in a severely dilated chamber of the heart, making this technique effective to use in clinical practice.

Cryoballoon ablation for atrial fibrillation without the use of a contrast medium: a combination of the intracardiac echocardiography and pressure wave monitoring guided approach.

In cryoballoon ablation (CBA), a contrast medium is commonly used to confirm balloon occlusion of the pulmonary veins (PVs). However, a contrast medium cannot always be used in patients with renal dysfunction and allergy. The present study aimed to assess the efficacy and safety of CBA without the use of a contrast medium. We retrospectively examined consecutive patients with paroxysmal atrial fibrillation (PAF) who underwent first-time CBA. We compared the procedural results and outcomes in patients for whom a contrast medium was used (contrast group) and those from whom a contrast medium was not used (non-contrast group). In the non-contrast group, we used saline injection on the intracardiac echocardiography and pressure wave monitoring for PV occlusion. Fifty patients (200 PVs) and 22 patients (88 PVs) underwent CBA with and without a contrast medium, respectively. The success rate of PV isolation with CBA alone was 93% and 90% in the non-contrast and contrast groups, respectively (p = 0.40). The fluoroscopy time and nadir temperature were significantly lower in the non-contrast group as compared to that in the contrast group. The recurrence rate 1 year after ablation did not differ between the two groups (18% vs. 18%, p > 0.99). Furthermore, the number of reconnected PVs in patients with recurrence was significantly lower in the non-contrast group than in the contrast group (6% vs. 36%, p = 0.017). In conclusion, CBA using the intracardiac echocardiography and pressure monitoring approach without the use of a contrast medium was safe and efficient.

Clinical Significance of the Left Atrial Appendage Orifice Area.

Objective The left atrial appendage (LAA) is one of the major sources of cardiac thrombus formation. Three-dimensional transesophageal echocardiography (TEE) made it possible to perform a detailed evaluation of the LAA morphologies. This study aimed to evaluate the clinical implications of the LAA orifice area. Methods A total of 149 patients who underwent TEE without significant valvular disease were studied. The LAA orifice area was measured using three-dimensional TEE. The patients were divided into two groups according to the LAA orifice area (large LAA orifice group, ≥median value, and small LAA orifice group). The clinical characteristics and echocardiographic findings were evaluated. Results The median LAA orifice area among all patients was 4.09 cm2 (interquartile range 2.92-5.40). The large LAA orifice group were older (67.2±10.4 vs. 62.4±15.3 years, p=0.02), more often had hypertension (66.7% vs. 44.6%, p=0.007), and atrial fibrillation (70.7% vs. 39.2%, p<0.001) than the small LAA orifice group. Regarding the TEE findings, the LAA flow velocity was significantly lower (33.7±20.0 vs. 50.2±24.3, p<0.001) and spontaneous echo contrast was more often observed (21.3% vs. 8.1%, p=0.02) in the large LAA orifice group. Multivariate models demonstrated that atrial fibrillation was an independent predictor of the LAA orifice area. In the analysis of atrial fibrillation duration, the LAA orifice area tended to be larger as patients had a longer duration of atrial fibrillation. Conclusion Our findings indicated that a larger LAA orifice area was associated with the presence of atrial fibrillation and high thromboembolic risk based on TEE findings. A continuation of the atrial fibrillation rhythm might lead to the gradual expansion of the LAA orifice.

Earliest pulmonary vein potential-guided cryoballoon ablation is associated with better clinical outcomes than conventional cryoballoon ablation: A result from two randomized clinical studies.

INTRODUCTION: With regard to short-term outcome in atrial fibrillation (AF), the benefit of cryoballoon ablation (CBA) by pressing a balloon against the earliest pulmonary vein (PV) potential site during PV isolation (earliest potential [EP]-guided CBA) has been previously demonstrated. The present study aimed to evaluate the long-term outcome of the EP-guided CBA. METHODS AND RESULTS: This study included 136 patients from two randomized studies, who underwent CBA for paroxysmal AF for the first time. Patients were randomly assigned to the EP-guided and conventional CBA groups in each study. In the EP-guided CBA group, we pressed a balloon against the EP site when the time-to-isolation (TTI) after cryoapplication exceeded 60 and 45 s in the first and second studies, respectively. We compared the clinical outcomes for 1 year after the procedure between the EP-guided CBA group (68 patients) and the conventional CBA group (68 patients). The primary endpoint was the recurrence of atrial arrhythmia after ablation. No significant differences in baseline characteristics were observed between the two groups. Compared with the conventional CBA group, the EP-guided CBA group had a significantly higher success rate at TTI ≤ 90 s (98.5% vs. 90.0%, p < .001); lower touch-up rate and total cryoapplication; and shorter procedure time, and fluoroscopy time. The recurrence at 1 year after ablation was significantly lower in the EP-guided CBA group than in the conventional CBA group (6.0% vs. 19.4%; p = .019). CONCLUSIONS: The EP-guided CBA approach can facilitate the ablation procedure and achieve low recurrence at 1 year after ablation.

Notch1 haploinsufficiency in mice accelerates adipogenesis.

Notch signaling has been recognized recently as a key regulator of metabolism. Here, we determined the role of Notch1 in adipogenesis in wild-type (WT) and Notch1 hetero-mutant (N1+/-) mice provided with 12-week normal or high-fat diet. Haploinsufficiency of Notch1 was associated with adipose tissue accumulation despite similar food intake. White adipose tissue (WAT) of N1+/- showed accumulation of adipogenic cells (CD34+CD68+ cells), crown-like structures, and upregulation of cell proliferation markers (cyclin D1 and Ki67). Notch1 expression in WAT reached peak levels in 8-week-old WT mice in parallel with fat accumulation, especially under HF/HS-feeding, whereas such increment was blunted in N1+/- mice. Downstream of Notch1 haploinsufficiency, over-expression of adipogenic factors PPARγ and C/EBPα was noted following down-regulation of downstream transcriptional factors of Notch signaling (Hes-1, Pref-1, and Sox9). Both pharmacological Notch signal inhibition and Notch1 knockdown enhanced adipogenesis of 3T3-L1 preadipocytes. N1+/- mice showed impaired glucose and insulin tolerance with downregulation of IRS-1 and GLUT4 in WAT after high-fat diet. Taken together, our results suggest that haploinsufficiency of Notch1 promotes fat accumulation and adipogenesis and provides a mechanistic link between Notch signaling and development of metabolic syndrome.

Disappearance pattern and the last remaining earliest pulmonary vein potential during cryoballoon ablation in predicting recurrence and conduction gap site of pulmonary veins.

Electrophysiological studies have rarely evaluated the sites prone to pulmonary vein (PV) conduction gap during cryoballoon ablation (CBA) for atrial fibrillation (AF). In addition, no studies have analyzed the sequence of PV potentials just before PV isolation during CBA for AF. Of the 238 patients who underwent first-time CBA for paroxysmal AF, 115 PVs of 29 patients who underwent repeat session due to recurrence after the procedure were retrospectively evaluated in the study. We evaluated the disappearance pattern of PV potential and PV reconnection on intracardiac electrograms and investigated whether the conduction gap site of the PV was related to the last remaining earliest PV potential (EP) and sequence pattern during the first-time CBA. Time to isolation was observed in 81 PVs during the first-time CBA. At the repeat session, PV reconnection was only observed in 22 of 81 PVs. PV potentials disappeared with sequence changes in 36 PVs and without sequence changes in 38 PVs. Multivariate analysis demonstrated that disappearance of PV potentials without change in the EP site but with delay or disappearance of other PV potentials was independently associated with PV reconnection (12/22 PVs [55%] vs. 4/59 PVs [6.8%]; odds ratio 14.4; 95% confidence interval 3.75-55.5; p < 0.001). In 19 of 22 (86%) reconnected PVs, PV conduction gap sites at repeat ablation corresponded with the last remaining EP sites during first-time CBA. In conclusion, disappearance pattern of the PV potential and the last remaining EP during the CBA can predict PV reconnection and gap site.

Impact of the clinical frailty scale on clinical outcomes and bleeding events in patients with ST-segment elevation myocardial infarction.

The Clinical Frailty Scale (CFS) is a simple tool to assess patients' frailty and may help to predict adverse outcomes in elderly patients. The aim of the present study was to examine the impact of CFS on clinical outcomes and bleeding events after successful percutaneous coronary intervention (PCI) in ST-segment elevation myocardial infarction (STEMI). We enrolled 266 consecutive patients with STEMI who underwent primary PCI in between January 2015 and June 2018. Patients were categorized into two groups based on the CFS stages: CFS 1-3 and CFS ≥ 4. We collected the data and evaluated the relationship between the CFS grade and the incidence of major adverse cardiovascular events (MACE) and Bleeding Academic Research Consortium 3 or 5 bleeding events. Of these patients, CFS ≥ 4 was present in 59 (22.2%). During the follow-up, 37.3% in the CFS ≥ 4 group and 8.2% in the CFS 1-3 group experienced MACE. In Kaplan-Meier analysis, the proportion of MACE-free survival for 4 years was significantly lower in the CFS ≥ 4 group (log-rank P < 0.001). Additionally, the proportion of bleeding event-free survival was significantly lower in the CFS ≥ 4 group (log-rank P < 0.001). The CFS (per 1-grade increase) remained an independent significant predictor of MACE on multivariate Cox proportional hazard analysis [hazard ratio 1.39 (95% confidence interval: 1.08 to 1.79, P = 0.01)]. In conclusion, CFS was an independent predictor of future adverse cardiac events in patients with STEMI. Therefore, the assessment of CFS is crucial in this population.

Impact of skeletal muscle mass on clinical outcomes in patients with severe aortic stenosis undergoing transcatheter aortic valve replacement.

Low skeletal muscle mass is one of the components of sarcopenia. However, the prognostic impact of skeletal muscle mass on clinical outcomes in patients after transcatheter aortic valve replacement (TAVR) remains unclear. Therefore, we assessed the impact of skeletal muscle mass on future cardiovascular events in patients undergoing TAVR. We enrolled 71 consecutive patients who underwent TAVR for symptomatic severe aortic stenosis. We applied bilateral psoas muscles as an indicator of skeletal muscle mass. Psoas muscle volumes were measured from the origin of psoas at the level of the lumbar vertebrae to its insertion in the lesser trochanter on three-dimensional computed tomography datasets. Psoas muscle mass index (PMI) was calculated as psoas muscle volume/height2 (cm3/m2). According to the median value of PMIs (79.8 and 60.0 cm3/m2 for men and women), the enrolled patients were divided into two groups. During the follow-up, 11 (31.4%) patients in low PMI group and 4 (11.1%) in high PMI group experienced major adverse cardiovascular events (MACE) defined as a composite of death from any cause, myocardial infarction, heart failure hospitalization, and stroke. The proportion of MACE-free survival was significantly lower in low PMI group (log-rank P = 0.033), mainly due to the difference of hospital readmission for congestive heart failure. On multivariate Cox proportional hazard analysis, PMI remained an independent negative predictor of MACE [hazard ratio 0.95 (95% confidence interval 0.92-0.98, P = 0.002)]. In conclusion, low skeletal muscle mass independently predicted MACE in patients undergoing TAVR.

Earliest pulmonary vein potential-guided cryoballoon ablation for atrial fibrillation.

No studies have evaluated both the time-to-isolation (TTI) and the sequence of pulmonary vein (PV) potentials in cryoballoon ablation (CBA) for atrial fibrillation (AF). This study aimed to prospectively evaluate the acute results of pulmonary vein isolation (PVI) using a novel CBA technique-the earliest potential (EP) of PV-guided CBA-in paroxysmal AF. We pressed a balloon against the earliest PV potential site during PVI when TTI could not be achieved within 60 s (EP-guided CBA group). We compared 32 patients consecutively treated by EP-guided CBA to 32 patients treated without pressing the balloon against the EP site (conventional CBA group). The cryoapplication protocol was the same, except with regard to the pressing of the balloon. All 256 PVs (EP-guided CBA group, 128 PVs; conventional CBA group, 128 PVs) were isolated successfully. The TTI observation rate was similar in both groups. Compared with conventional CBA, EP-guided CBA was associated with a lower non-success rate of TTI ≤ 90 s (9% vs. 26%; P = 0.040) and shorter left atrial dwell time (38 ± 9 vs. 46 ± 19 min; P = 0.036), total procedure time (76 ± 15 vs. 87 ± 23 min; P = 0.043), and fluoroscopy time (23 ± 8 vs. 30 ± 11 min; P = 0.006). This novel EP-guided CBA approach may help facilitate the ablation procedure.

A Golgi-targeting fluorescent probe for labile Fe(ii) to reveal an abnormal cellular iron distribution induced by dysfunction of VPS35.

Iron is involved in numerous physiologically essential processes in our body. However, excessive iron is a pathogenic factor in neurodegenerative diseases, causing aberrant oxidative stress. Divalent metal transporter 1 (DMT1) acts as a primary transporter of Fe(ii) ions. The intracellular delivery of DMT1 toward the cellular membrane via the trans-Golgi network during the endocytotic process is partially regulated by a retromer-mediated protein-sorting system comprising vacuolar protein-sorting proteins (VPSs). Thus, together with DMT1, the Golgi-apparatus acts as a hub organelle in the delivery system for intracellular Fe(ii) ions. Dysfunction of the VPS-relevant protein sorting system can induce the abnormal delivery of DMT1 toward lysosomes concomitantly with Fe(ii) ions. To explore this issue, we developed a fluorescent probe, Gol-SiRhoNox, for the Golgi-specific detection of Fe(ii) ions by integrating our original N-oxide-based Fe(ii)-specific chemical switch, a new Golgi-localizable chemical motif, and polarity-sensitive fluorogenic scaffold. Our synchronous imaging study using Gol-SiRhoNox and LysoRhoNox, a previously developed fluorescent probe for lysosomal Fe(ii), revealed that the intracellular distribution balance of Fe(ii) ions between the Golgi apparatus and lysosomes is normally Golgi-dominant, whereas the lysosome-specific elevation of Fe(ii) ions was observed in cells with induced dysfunction of VPS35, a member of the retromer complex. Treatment of cells with dysfunctional VPS35 with R55, a molecular chaperone, resulted in the restoration of the subcellular distribution of Fe(ii) ions to the Golgi-dominant state. These results indicate that the impairment of the DMT1 traffic machinery affects subcellular iron homeostasis, promoting Fe(ii) leakage at the Golgi and lysosomal accumulation of Fe(ii) through missorting of DMT1.

Angiotensin receptor blocker irbesartan reduces stress-induced intestinal inflammation via AT1a signaling and ACE2-dependent mechanism in mice.

Stress is associated with pathophysiology of both irritable bowel syndrome (IBS) and hypertension. Angiotensin receptor blockers (ARB) have anti-inflammatory properties via inhibition of angiotensin II (Ang II)/Ang II type I receptor axis (AT1). Inhibition of the classical RAS pathway is also involved in upregulation of angiotensin converting enzyme-2 (ACE2), which activates the Ang-(1-7)/Mas pathway to counteract inflammatory signaling and acts as a partner of the amino acid transporter, B0AT-1, to absorb tryptophan for regulation of microbiota-gut-brain axis. In this study, we determined the effects of ARB irbesartan on stress-induced intestinal inflammation. C57BL/6J mice were subjected to 2-week intermittent restraint stress. They were orally treated during the stress with either vehicle, 3 or 10 mg/kg/day irbesartan. Restraint stress resulted in colon inflammation with higher histological damage scores, increased expression of Nox4, TLR-4 and IL1-ß, accumulation of reactive oxygen species (ROS), and activation of the ACE-angiotensin II-AT1 receptor axis. Stress also downregulated intestinal amino acid transporter, ACE2/B0AT-1, and activity of intestinal mammalian target of rapamycin (mTOR) and p70 S6 kinase (p70S6K), resulting in decrease in α-defensins, changes in intestinal microbial contents, and perturbation of tryptophan metabolism with activation of the kynurenine pathway. Administration of irbesartan inhibited activation of stress-induced AT1 pathway to reduce intestinal ROS accumulation and inflammation, restored expression of ACE2/B0AT-1, activity of mTOR and p70S6K, dysbiosis and tryptophan metabolism. Our results suggest that AT1 is a potentially suitable therapeutic target in stress-induced intestinal inflammation, and that irbesartan could be beneficially suitable for the treatment of stressed patients with IBS.

Impact of Coronary Stent Fracture on Restenotic Neointimal Tissue Characterization After Drug-Eluting Stent Implantation.

Although drug-eluting stents (DESs) reduce the rates of in-stent restenosis (ISR) and subsequent target lesion revascularization, stent fracture (SF) after DES implantation has become an important concern because of its potential association with restenosis and stent thrombosis. We aimed to assess the pathogenic impact of SF on in-stent restenotic neointimal tissue components after DES implantation. We analyzed 43 consecutive patients (14 with SF and 29 without SF) with ISR requiring revascularization after DES implantation between January 2008 and March 2014. For evaluation of in-stent tissue components, integrated backscatter intravascular ultrasound (IB-IVUS) was performed. SF was defined as complete or partial separation of stent segments observed using plain fluoroscopy or intravascular ultrasound. On volumetric IB-IVUS analyses, patients with SF had a significantly higher percentage of lipid tissue volume within the neointima and a significantly lower percentage of fibrous tissue volume than those without (37.3 ± 18.9% versus 24.9 ± 12.4%, P = 0.02, and 61.2 ± 18.3 versus 72.6 ± 12.1%, P = 0.04, respectively). Moreover, SF was positively correlated with the percentage of lipid volume on multiple linear regression analysis after adjustment for confounding factors (ß = 0.36, P = 0.03). The interval from stent implantation was similar in both groups (47.0 ± 28.7 versus 37.7 ± 33.3 months; P = 0.39). In conclusion, SF is associated with larger lipid tissue volume within the neointima after DES placement, suggesting a contribution to the development of neoatherosclerosis and vulnerable neointima. Thus SF might lead to future adverse coronary events.

Xanthine oxidase inhibition by febuxostat attenuates stress-induced hyperuricemia, glucose dysmetabolism, and prothrombotic state in mice.

Chronic stress is closely linked to the metabolic syndrome, diabetes, hyperuricemia and thromboembolism, but the mechanisms remain elusive. We reported recently that stress targets visceral adipose tissue (VAT), inducing lipolysis, low-grade inflammation with production of inflammatory adipokines, metabolic derangements such as insulin resistance, and prothrombotic state. In the present study, we hypothesized the involvement of VAT xanthine oxidoreductase (XOR), a source of reactive oxygen species (ROS) and uric acid (UA) in the above processes. Restraint stress in mice resulted in upregulation of XOR and xanthine oxidase activity, accumulation of ROS in VAT as well as liver and intestine, increase in serum UA levels, upregulation of NADPH oxidase subunits and downregulation of antioxidant enzymes. Immunohistochemistry and RT-PCR analysis also showed that restraint stress induced VAT monocyte accumulation and proinflammatory adipokine production, resulting in reduced insulin sensitivity and induction of plasminogen activator inhibitor-1 and tissue factor in VAT. Treatment with febuxostat, a potent XO inhibitor, suppressed stress-induced ROS production and VAT inflammation, resulting in improvement of serum UA levels, insulin sensitivity, and prothrombotic tendency. Our results suggest that stress perturbs glucose and UA metabolism, and promotes prothrombotic status, and that XO inhibition by febuxostat might be a potential therapy for stress-related disorders.

Dipeptidyl peptidase- IV inhibitor alogliptin improves stress-induced insulin resistance and prothrombotic state in a murine model.

BACKGROUND: Stress evokes lipolytic release of free fatty acid (FFA) and low-grade inflammation in visceral adipose tissue, mediated by increased adipokine secretion, and contributes to glucose metabolism disorder and prothrombotic state. We tested the hypothesis that alogliptin, a dipeptidyl peptidase-4 inhibitor, can ameliorate the biological effects of chronic stress in mice. METHOD AND RESULTS: C57BL/6J mice were subjected to 2-week intermittent restraint stress and orally treated with vehicle or alogliptin (dose: 15 or 45mg/kg/day). Plasma levels of lipids, proinflammatory cytokines (monocyte chemoattractant protein-1, tumor necrosis factor-α, and interleukin-6), and 8-hydroxydeoxyguanosine were measured with enzyme-linked immunosorbent assay. Monocyte/macrophage accumulation in inguinal white adipose tissue (WAT) was examined by CD11b-positive cell count and mRNA expression of CD68 and F4/80 was examined by immunohistochemistry and RT-PCR, respectively. The mRNA levels of the above-mentioned proinflammatory cytokines, NADPH oxidase 4, adiponectin, and coagulation factors (plasminogen activation inhibitor-1 and tissue factor) in WAT were also assessed with RT-PCR. Glucose metabolism was assessed by glucose and insulin tolerance tests, plasma levels of DPP-4 activity, glucagon-like peptide-1, expression of DPP-4, insulin receptor substrate-1 and glucose transporter 4 in WAT and skeletal muscle. Alogliptin administration suppressed stress-induced FFA release, oxidative stress, adipose tissue inflammation, DPP-4 activation, and prothrombotic state in a dose-dependent manner, and improved insulin sensitivity in stressed mice. CONCLUSIONS: The results indicate that alogliptin improves stress-induced prothrombotic state and insulin resistance; suggesting that alogliptin could have beneficial therapeutic effects against cardiovascular complications in diabetic patients under stress.