Long-term results of ablation index guided atrial fibrillation ablation: insights after 5+ years of follow-up from the MPH AF Ablation Registry

Background

Catheter ablation (CA) for symptomatic atrial fibrillation (AF) offers the best outcomes for patients. Despite the benefits of CA, a significant proportion of patients suffer a recurrence; hence, there is scope to potentially improve outcomes through technical innovations such as ablation index (AI) guidance during AF ablation. We present real-world 5-year follow-up data of AI-guided pulmonary vein isolation.

Methods

We retrospectively followed 123 consecutive patients who underwent AI-guided CA shortly after its introduction to routine practice. Data were collected from the MPH AF Ablation Registry with the approval of the institutional research board.

Results

Our patient cohort was older, with higher BMI, greater CHA2DS2-VASc scores, and larger left atrial sizes compared to similar previously published cohorts, while gender balance and other characteristics were similar. The probability of freedom from atrial arrhythmia with repeat procedures is as follows: year 1: 0.95, year 2: 0.92, year 3: 0.85, year 4: 0.79, and year 5: 0.72. Age >75 years (p = 0.02, HR: 2.7, CI: 1.14-6.7), BMI >35 kg/m2 (p = 0.0009, HR: 4.6, CI: 1.8-11.4), and left atrial width as measured on CT in the upper quartile (p = 0.04, HR: 2.5, CI: 1-5.7) were statistically significant independent predictors of recurrent AF.

Conclusion

AI-guided CA is an effective treatment for AF, with 95.8% of patients remaining free from atrial arrhythmia at 1 year and 72.3% at 5 years, allowing for repeat procedures. It is safe with a low major complication rate of 1.25%. Age >75 years, BMI >35 kg/m2, and markedly enlarged atria were associated with higher recurrence rates.

[Ⅱ ]

Objective: To investigate the role and related mechanism of ubiquitin-like protein FAT10 in the angiotensin Ⅱ (AngⅡ)-induced endothelial cell inflammatory responses. Methods: The Western blot was used to detect the protein expression of FAT10 in 16-weeks old WKY rat carotid artery, thoracic aorta artery, renal artery and vascular smooth muscle cells (VSMC), human umbilical vein endothelial cells (HUVEC) and human breast cancer cells (MDA-MB-231). The optimal concentration and stimulation time of AngⅡ on inducing the highest FAT10 in HUVEC were determined. The following plasmids were constructed: control plasmid, overexpression FAT10 plasmid (Flag-FAT10), invalid interference plasmid, and interference FAT10 plasmid (sh-FAT10). These plasmids were then transfected into HUVEC cells and divided into following groups: control group, Flag-FAT10 group, invalid interference group, and sh-FAT10 group. After culturing with 100 nmol/L AngⅡ for 36 h, the control group and the Flag-FAT10 group were treated with reactive oxygen species scavenger N-acetyl-L-cysteine ​​(NAC), the protein expression levels of the inflammatory factor monocyte chemotactic protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α) were measured. Laser confocal microscopy was used to detect the generation levels of reactive oxygen species in the cells of vrious groups. Results: FAT10 was expressed in carotid artery, thoracic aorta, and renal artery of normal blood pressure rats and expressed in HUVEC, VSMC, MDA-MB-231. The expression level of FAT10 gradually increased in proportion to the increase of the time and concentration of AngⅡ stimulation in HUVEC, and the expression level of FAT10 was the highest when the HUVEC was treated with 100 nmol/L AngⅡ for 36 h (P<0.01). The protein expression level of MCP-1 (P<0.001) and TNF-α (P<0.01) was higher in AngⅡ treated HUVEC with FAT10 overexpression, while the expression level of MCP-1 and TNF-α protein was lower in AngⅡ treated HUVEC with FAT10 knockdown (all P<0.01). The level of intracellular reactive oxygen species (ROS) production was significantly increased with FAT10 overexpression (P<0.001), and the level of ROS was decreased when the expression of FAT10 was interfered (P<0.05). The increased level of MCP-1 and TNF-α proteins in FAT10 overexpressed HUVEC was reversed by NAC (all P<0.05). Conclusion: FAT10 promotes the release of inflammatory factors induced by AngⅡ in endothelial cells by increasing the level of intracellular ROS production.

Postnatal development of extracellular matrix and vascular function in small arteries of the rat

Introduction: Vascular extracellular matrix (ECM) is dominated by elastic fibers (elastin with fibrillin-rich microfibrils) and collagens. Current understanding of ECM protein development largely comes from studies of conduit vessels (e.g., aorta) while resistance vessel data are sparse. With an emphasis on elastin, we examined whether changes in postnatal expression of arteriolar wall ECM would correlate with development of local vasoregulatory mechanisms such as the myogenic response and endothelium-dependent dilation. Methods: Rat cerebral and mesenteric arteries were isolated at ages 3, 7, 11, 14, 19 days, 2 months, and 2 years. Using qPCR mRNA expression patterns were examined for elastin, collagen types I, II, III, IV, fibrillin-1, and -2, lysyl oxidase (LOX), and transglutaminase 2. Results: Elastin, LOX and fibrillar collagens I and III mRNA peaked at day 11-14 in both vasculatures before declining at later time-points. 3D confocal imaging for elastin showed continuous remodeling in the adventitia and the internal elastic lamina for both cerebral and mesenteric vessels. Myogenic responsiveness in cannulated cerebral arteries was detectable at day 3 with constriction shifted to higher intraluminal pressures by day 19. Myogenic responsiveness of mesenteric vessels appeared fully developed by day 3. Functional studies were performed to investigate developmental changes in endothelial-dependent dilation. Endothelial-dependent dilation to acetylcholine was less at day 3 compared to day 19 and at day 3 lacked an endothelial-derived hyperpolarizing factor component that was evident at day 19. Conclusion: Collectively, in the rat small artery structural remodeling and aspects of functional control continue to develop in the immediate postnatal period.

Protein-Added Healthy Lunch-Boxes Combined with Exercise for Improving Physical Fitness and Vascular Function in Pre-Frail Older Women: A Community-Based Randomized Controlled Trial

Purpose

Preventive or therapeutic interventions are key to maintaining independence in pre-frail and/or frail elderly. Therefore, we investigated whether multi-component interventions were effective in physical fitness levels and vascular functions in pre-frail older women.

Patients and Methods

Sixty participants aged ≥ 65 years (81.5 ± 4.3 yrs) were divided equally into control group, diet group, aerobic exercise and diet group, and aerobic exercise with electromyostimulation and diet group. For 8 weeks, the participants received a set of protein-added meals twice daily on weekdays. The aerobic exercise groups performed 45 mins of stepping exercise at 50-70% of the maximal heart rate for 3 days/week, and the aerobic exercise with electromyostimulation was applied on each limb in 8 weeks. Blood pressure, physical fitness, cardiovascular biomarkers, pulse wave velocity, and flow-mediated dilation were measured before and after the 8-week.

Results

There were no group differences in age, height, weight, body mass index, free fat mass, and %body fat at baseline. The right grip strength significantly increased in the diet group, aerobic exercise and diet group, and aerobic exercise with electromyostimulation and diet group (p < 0.05). Short physical performance battery, 6-min walking distance, and flow-mediated dilation significantly increased in the aerobic exercise and diet group and aerobic exercise with electromyostimulation and diet group (p < 0.05). Blood pressure and pulse wave velocity did not differ between interventions. High-density lipoprotein-cholesterol levels significantly increased after 8 weeks in all intervention groups (p < 0.05). There were no significant differences in glucose, HbA1c, total cholesterol, low-density lipoprotein-cholesterol, triglyceride, insulin, Homeostatic Model Assessment for Insulin Resistance, nitric oxide, and C-reactive protein levels.

Conclusion

These results show that multi-component interventions appear to improve physical fitness and vascular function in pre-frail older women. Thus, possible strategies to prevent early frailty including proper nutrition and exercise may be needed.

Screen media and non-screen media habits among preschool children in Singapore, South Korea, Japan, and Finland: Insights from an unsupervised clustering approach

The main purpose of the research was to describe the daily screen media habits and non-screen media habits like indoor and outdoor play, and sleep of preschool children aged 2 to 6 years from Singapore, South Korea, Japan, and Finland using a content-validated online questionnaire (SMALLQ®) and unsupervised cluster analysis. Unsupervised cluster analysis on 5809 parent-reported weekday and weekend screen and non-screen media habits of preschool children from the four countries resulted in seven emergent clusters. Cluster 2 (n = 1288) or the Early-screen media, screen media-lite and moderate-to-vigorous physical activity-lite family made up 22.2% and Cluster 1 (n = 261) or the High-all-round activity and screen media-late family made up 4.5%, respectively represented the largest and smallest clusters among the seven clusters that were emergent from the pooled dataset. Finland was best represented by Cluster 2 and Japan was best represented by Cluster 3 (High-screen media-for-entertainment and low-engagement family). Parents from Finland and Japan displayed greater homogeneity in terms of the screen media and non-screen media habits of preschool children than the parents from South Korea and Singapore. South Korea was best represented by Clusters 6 (Screen media-physical activity-engagement hands-off family) and 7 (Screen media-lite, screen media-late and high-physical activity family). Singapore was best represented by Clusters 4, 5, 6 and 7, and these clusters ranged from Low all-round activity-high nap time family to Screen media-lite, screen media-late and high-physical activity family. Future research should explore in-depth reasons for the across-country and within-country cluster characteristics of screen media and non-screen media habits among preschool children to allow for more targeted interventions.

Robust Pulse Rate Measurements from Facial Videos in Diverse Environments

Pulse wave and pulse rate are important indicators of cardiovascular health. Technologies that can check the pulse by contacting the skin with optical sensors built into smart devices have been developed. However, this may cause inconvenience, such as foreign body sensation. Accordingly, studies have been conducted on non-contact pulse rate measurements using facial videos focused on the indoors. Moreover, since the majority of studies are conducted indoors, the error in the pulse rate measurement in outdoor environments, such as an outdoor bench, car and drone, is high. In this paper, to deal with this issue, we focus on developing a robust pulse measurement method based on facial videos taken in diverse environments. The proposed method stably detects faces by removing high-frequency components of face coordinate signals derived from fine body tremors and illumination conditions. It optimizes for extracting skin color changes by reducing illumination-caused noise using the Cg color difference component. The robust pulse wave is extracted from the Cg signal using FFT-iFFT with zero-padding. It can eliminate signal-filtering distortion effectively. We demonstrate that the proposed method relieves pulse rate measurement problems, producing 3.36, 5.81, and 6.09 bpm RMSE for an outdoor bench, driving car, and flying drone, respectively.

Endothelial alpha globin is a nitrite reductase

Resistance artery vasodilation in response to hypoxia is essential for matching tissue oxygen and demand. In hypoxia, erythrocytic hemoglobin tetramers produce nitric oxide through nitrite reduction. We hypothesized that the alpha subunit of hemoglobin expressed in endothelium also facilitates nitrite reduction proximal to smooth muscle. Here, we create two mouse strains to test this: an endothelial-specific alpha globin knockout (EC Hba1Δ/Δ) and another with an alpha globin allele mutated to prevent alpha globin's inhibitory interaction with endothelial nitric oxide synthase (Hba1WT/Δ36-39). The EC Hba1Δ/Δ mice had significantly decreased exercise capacity and intracellular nitrite consumption in hypoxic conditions, an effect absent in Hba1WT/Δ36-39 mice. Hypoxia-induced vasodilation is significantly decreased in arteries from EC Hba1Δ/Δ, but not Hba1WT/Δ36-39 mice. Hypoxia also does not lower blood pressure in EC Hba1Δ/Δ mice. We conclude the presence of alpha globin in resistance artery endothelium acts as a nitrite reductase providing local nitric oxide in response to hypoxia.

Brain-mimicking phantom for biomechanical validation of motion sensitive MR imaging techniques

Motion sensitive MR imaging techniques allow for the non-invasive evaluation of biological tissues by using different excitation schemes, including physiological/intrinsic motions caused by cardiac pulsation or respiration, and vibrations caused by an external actuator. The mechanical biomarkers extracted through these imaging techniques have been shown to hold diagnostic value for various neurological disorders and conditions. Amplified MRI (aMRI), a cardiac gated imaging technique, can help track and quantify low frequency intrinsic motion of the brain. As for high frequency actuation, the mechanical response of brain tissue can be measured by applying external high frequency actuation in combination with a motion sensitive MR imaging sequence called Magnetic Resonance Elastography (MRE). Due to the frequency-dependent behavior of brain mechanics, there is a need to develop brain phantom models that can mimic the broadband mechanical response of the brain in order to validate motion-sensitive MR imaging techniques. Here, we have designed a novel phantom test setup that enables both the low and high frequency responses of a brain-mimicking phantom to be captured, allowing for both aMRI and MRE imaging techniques to be applied on the same phantom model. This setup combines two different vibration sources: a pneumatic actuator, for low frequency/intrinsic motion (1 Hz) for use in aMRI, and a piezoelectric actuator for high frequency actuation (30-60 Hz) for use in MRE. Our results show that in MRE experiments performed from 30 Hz through 60 Hz, propagating shear waves attenuate faster at higher driving frequencies, consistent with results in the literature. Furthermore, actuator coupling has a substantial effect on wave amplitude, with weaker coupling causing lower amplitude wave field images, specifically shown in the top-surface shear loading configuration. For intrinsic actuation, our results indicate that aMRI linearly amplifies motion up to at least an amplification factor of 9 for instances of both visible and sub-voxel motion, validated by varying power levels of pneumatic actuation (40%-80% power) under MR, and through video analysis outside the MRI scanner room. While this investigation used a homogeneous brain-mimicking phantom, our setup can be used to study the mechanics of non-homogeneous phantom configurations with bio-interfaces in the future.

Potential of cannabinoids as treatments for autism spectrum disorders

Current treatments for autism spectrum disorders (ASD) are limited in efficacy and are often associated with substantial side effects. These medications typically ameliorate problem behaviors associated with ASD, but do not target core symptom domains. As a result, there is a significant amount of research underway for development of novel experimental therapeutics. Endocannabinoids are arachidonic acid-derived lipid neuromodulators, which, in combination with their receptors and associated metabolic enzymes, constitute the endocannabinoid (EC) system. Cannabinoid signaling may be involved in the social impairment and repetitive behaviors observed in those with ASD. In this review, we discuss a possible role of the EC system in excitatory-inhibitory (E-I) imbalance and immune dysregulation in ASD. Novel treatments for the core symptom domains of ASD are needed and phytocannabinoids could be useful experimental therapeutics for core symptoms and associated domains.

A venous-specific purinergic signaling cascade initiated by Pannexin 1 regulates TNFα-induced increases in endothelial permeability

The endothelial cell barrier regulates the passage of fluid between the bloodstream and underlying tissues, and barrier function impairment exacerbates the severity of inflammatory insults. To understand how inflammation alters vessel permeability, we studied the effects of the proinflammatory cytokine TNFα on transendothelial permeability and electrophysiology in ex vivo murine veins and arteries. We found that TNFα specifically decreased the barrier function of venous endothelium without affecting that of arterial endothelium. On the basis of RNA expression profiling and protein analysis, we found that claudin-11 (CLDN11) was the predominant claudin in venous endothelial cells and that there was little, if any, CLDN11 in arterial endothelial cells. Consistent with a difference in claudin composition, TNFα increased the permselectivity of Cl^- over Na⁺ in venous but not arterial endothelium. The vein-specific effects of TNFα also required the activation of Pannexin 1 (Panx1) channels and the CD39-mediated hydrolysis of ATP to adenosine, which subsequently stimulated A_2A adenosine receptors. Moreover, the increase in vein permeability required the activation of the Ca²⁺ channel TRPV4 downstream of Panx1 activation. Panx1-deficient mice resisted the pathologic effects of sepsis induced by cecal ligation and puncture on life span and lung vascular permeability. These data provide a targetable pathway with the potential to promote vein barrier function and prevent the deleterious effects of vascular leak in response to inflammation.

[Prevalence of CYP2C19 gene mutations in patients with coronary heart disease and its biological activation effect in clopidogrel antiplatelet response]

Objective: The purpose of this study was to investigate the effects of CYP2C19 gene mutations on clopidogrel antiplatelet activity in the patients with coronary heart disease treated by percutaneous coronary intervention. Methods: Patients with coronary heart disease, who hospitalized in the Second Affiliated Hospital of Nanchang University from March 2011 to June 2019, and healthy individuals with matching genetic background, gender, and age as controls were included in this study. Basic clinical data were analyzed and blood samples of all research subjects were obtained for extraction of DNA, and Sanger first-generation sequencing method was used to detect CYP2C19 gene mutation from full exon and exon and intron junction. CYP2C19 gene variations in patients with coronary heart disease were compared with the 1000 Genomes Browse database and the sequencing results of healthy controls to determine whether the gene variation was a genetic mutation or a genetic polymorphism. After that, PolyPhen-2 prediction software was used to analyze the harmfulness of gene mutations to predict the effect of mutations on protein function. The same dose of CYP2C19 wild-type plasmid and the CYP2C19 gene mutant plasmids were transfected into human normal liver cells HL-7702. After transfection of 24 h, the expression of CYP2C19 protease in each group was detected. The liver S9 protein was incubated with clopidogrel, acted on platelets to detect the platelet aggregation rate and the activity of human vasodilator-activated phosphoprotein (VASP). Results: A total of 1 493 patients with coronary heart disease (59.36%) were enrolled, the average age was (64.5±10.4) years old, of which 1 129 were male (75.62%). Meanwhile, 1 022 healthy physical examination volunteers (40.64%) were enrolled, and the average age was (64.1±11.0) years old, of which 778 were male (76.13%). A total of 5 gene mutations of CYP2C19 gene were identified in 12 patients (0.80%), namely, 4 known mutations T130K (1 case), M136K (6 cases), N277K (3 cases), V472I (1 case) and one new mutation G27V (1 case), no corresponding gene mutation was found in healthy controls. It was found that T130K and M136K were probably damaging, G27V was possibly damaging, and N277K and V472I were benign mutations. In vitro, we demonstrated that the platelet aggregation rate of the M136K gene mutation group was 24.83% lower than that of the wild type (59.58% vs. 34.75%; P<0.05), and the phosphorylated VASP level was 23.0% higher than that of the wild type (1.0 vs. 1.23; P<0.05). However, the platelet aggregation rate and phosphorylated VASP level were similar between of G27V, T130K, N277K, V472I gene mutation groups and wild type group (P>0.05). Conclusions: In this study, 5 gene mutations are defined in patients with coronary heart disease, namely G27V, T130K, M136K, N277K, V472I. In vitro functional studies show that CYP2C19 gene mutation M136K, as a gain-of-function gene mutation, can enhance the activation of CYP2C19 enzyme on clopidogrel, thereby inhibiting the platelet aggregation rate.

Apical sparing strain pattern observed in danon disease: insights from a global registry

Background

Danon Disease (DD) is a rare X-linked autophagic disorder due to mutations in the Lysosomal Associated Membrane Protein 2 (LAMP-2) gene and causes severe cardiac manifestations. Measurement of longitudinal strain (LS) has been shown to provide diagnostic insights into different etiologies of hypertrophic cardiomyopathies compared to conventional echocardiographic parameters.

Purpose

The aim of this study was to describe the pattern of global and regional LS in DD.

Methods

A retrospective, international registry, using medical records provided by patients, was formed to describe the natural history of DD. Complete echocardiogram images were available for review and LS was analyzed globally and regionally (basal, mid, apex).

Results

A total of eighteen DD patients (male 72%, mean age 17.2±10 years) had sufficient quality echocardiographic images for both traditional and myocardial strain evaluation. Notable traditional echocardiographic parameters included a mean EF of 60±11%, LV mass index 200±159 g/m2, intraventricular septal diameter 17.7±10.3 mm, LV posterior wall diameter 16.1±7.7 mm, LA volume index 21.9±13 mL/m2. Global longitudinal strain was reduced with a mean of −12.1±4.9% with an observed regional strain gradient: apex (−16.6±6.6%), mid (−10.9±4.7%) and basal (−9.2±4.5%). Bull's eye plot patterns reflected an apical sparing pattern that was similar to that described in cardiac amyloidosis.

Conclusion

In this DD cohort, we describe for the first time a strain pattern characterized by reduction in global longitudinal strain with apical sparing, which was originally pathognomonic for cardiac amyloidosis. This strain pattern in conjunction with a paradoxically normal LA volume may discriminate patients with DD from other hypertrophic conditions.

Funding Acknowledgement

Type of funding source: None

Jaceosidin Ameliorates Insulin Resistance and Kidney Dysfunction by Enhancing Insulin Receptor Signaling and the Antioxidant Defense System in Type 2 Diabetic Mice

Emerging evidence has shown that flavonoids extracted from Artemisia have beneficial effects on metabolic disorders. However, whether and how jaceosidin ameliorates insulin resistance and diabetic nephropathy in type 2 diabetes mellitus is largely unknown. For 8 weeks, db/db diabetic mice were fed with or without jaceosidin. Oral jaceosidin supplementation reduced fasting blood glucose levels and insulin resistance through the upregulation of insulin receptor downstream pathways in the liver and skeletal muscles. While jaceosidin did not noticeably alter kidney filtration function, this dietary intervention contributed to attenuating the accumulation of advanced glycation end products in diabetic kidneys. The levels of VEGF-a (vascular endothelial growth factor-a) proteins in the diabetic kidneys were markedly diminished by jaceosidin treatments, which increased the expression and activity of Cu (copper) and Zn-SOD (zinc-superoxide dismutase). Therefore, it is suggested that jaceosidin supplementation elicits antidiabetic effects and treats diabetic nephropathy by augmenting insulin signaling, suppressing fibrosis, and enhancing antioxidant activity.

Giant isotope effect on phonon dispersion and thermal conductivity in methylammonium lead iodide

Lead halide perovskites are strong candidates for high-performance low-cost photovoltaics, light emission, and detection applications. A hot-phonon bottleneck effect significantly extends the cooling time of hot charge carriers, which thermalize through carrier-optic phonon scattering, followed by optic phonon decay to acoustic phonons and finally thermal conduction. To understand these processes, we adjust the lattice dynamics independently of electronics by changing isotopes. We show that doubling the mass of hydrogen in methylammonium lead iodide by replacing protons with deuterons causes a large 20 to 50% softening of the longitudinal acoustic phonons near zone boundaries, reduces thermal conductivity by ~50%, and slows carrier relaxation kinetics. Phonon softening is attributed to anticrossing with the slowed libration modes of the deuterated molecules and the reduced thermal conductivity to lowered phonon velocities. Our results reveal how tuning the organic molecule dynamics enables control of phonons important to thermal conductivity and the hot-phonon bottleneck.

Local Peroxynitrite Impairs Endothelial Transient Receptor Potential Vanilloid 4 Channels and Elevates Blood Pressure in Obesity

BACKGROUND

Impaired endothelium-dependent vasodilation is a hallmark of obesity-induced hypertension. The recognition that Ca2+ signaling in endothelial cells promotes vasodilation has led to the hypothesis that endothelial Ca2+ signaling is compromised during obesity, but the underlying abnormality is unknown. In this regard, transient receptor potential vanilloid 4 (TRPV4) ion channels are a major Ca2+ influx pathway in endothelial cells, and regulatory protein AKAP150 (A-kinase anchoring protein 150) enhances the activity of TRPV4 channels.

METHODS

We used endothelium-specific knockout mice and high-fat diet-fed mice to assess the role of endothelial AKAP150-TRPV4 signaling in blood pressure regulation under normal and obese conditions. We further determined the role of peroxynitrite, an oxidant molecule generated from the reaction between nitric oxide and superoxide radicals, in impairing endothelial AKAP150-TRPV4 signaling in obesity and assessed the effectiveness of peroxynitrite inhibition in rescuing endothelial AKAP150-TRPV4 signaling in obesity. The clinical relevance of our findings was evaluated in arteries from nonobese and obese individuals.

RESULTS

We show that Ca2+ influx through TRPV4 channels at myoendothelial projections to smooth muscle cells decreases resting blood pressure in nonobese mice, a response that is diminished in obese mice. Counterintuitively, release of the vasodilator molecule nitric oxide attenuated endothelial TRPV4 channel activity and vasodilation in obese animals. Increased activities of inducible nitric oxide synthase and NADPH oxidase 1 enzymes at myoendothelial projections in obese mice generated higher levels of nitric oxide and superoxide radicals, resulting in increased local peroxynitrite formation and subsequent oxidation of the regulatory protein AKAP150 at cysteine 36, to impair AKAP150-TRPV4 channel signaling at myoendothelial projections. Strategies that lowered peroxynitrite levels prevented cysteine 36 oxidation of AKAP150 and rescued endothelial AKAP150-TRPV4 signaling, vasodilation, and blood pressure in obesity. Peroxynitrite-dependent impairment of endothelial TRPV4 channel activity and vasodilation was also observed in the arteries from obese patients.

CONCLUSIONS

These data suggest that a spatially restricted impairment of endothelial TRPV4 channels contributes to obesity-induced hypertension and imply that inhibiting peroxynitrite might represent a strategy for normalizing endothelial TRPV4 channel activity, vasodilation, and blood pressure in obesity.

Endothelial calreticulin deletion impairs endothelial function in aged mice

Discrete calcium signals within the vascular endothelium decrease with age and contribute to impaired endothelial-dependent vasodilation. Calreticulin (Calr), a multifunctional calcium binding protein and endoplasmic reticulum (ER) chaperone, can mediate calcium signals and vascular function within the endothelial cells (ECs) of small resistance arteries. We found Calr protein expression significantly decreases with age in mesenteric arteries and examined the functional role of EC Calr in vasodilation and calcium mobilization in the context of aging. Third-order mesenteric arteries from mice with or without EC Calr knockdown were examined for calcium signals and constriction to phenylephrine (PE) or vasodilation to carbachol (CCh) after 75 wk of age. PE constriction in aged mice with or without EC Calr was unchanged. However, calcium signals and vasodilation to endothelial-dependent agonist carbachol were significantly impaired in aged EC Calr knockdown mice. Ex vivo incubation of arteries with the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) significantly improved vasodilation in mice lacking EC Calr. Our data suggests diminished vascular Calr expression with age can contribute to the detrimental effects of aging on endothelial calcium regulation and vasodilation.NEW & NOTEWORTHY Calreticulin (Calr) is responsible for key physiological processes in endoplasmic reticulum, especially in aging tissue. In particular, endothelial Calr is crucial to vascular function. In this study, we deleted Calr from the endothelium and aged the mice up to 75 wk to examine changes in vascular function. We found two key differences: 1) calcium events in endothelium were severely diminished after muscarinic stimulation, which 2) corresponded with a dramatic decrease in muscarinic vasodilation. Remarkably, we were able to rescue the effect of Calr deletion on endothelial-dependent vasodilatory function using tauroursodeoxycholic acid (TUDCA), an inhibitor of endoplasmic reticulum stress that is currently in clinical trials.

Effect of abduction on avascular necrosis of the femoral epiphysis in patients with late-detected developmental dysplasia of the hip treated by closed reduction: a MRI study of 59 hips

PURPOSE

The purpose of this study was to explore whether increasing the hip abduction angle would increase the incidence of avascular necrosis (AVN) in patients with late- detected developmental dysplasia of the hip (DDH) treated by closed reduction (CR) and spica cast immobilization.

METHODS

A total of 55 patients (59 hips) with late-detected DDH underwent MRI after CR. Hip abduction angle and hip joint distance were measured on postoperative MRI transverse sections. The acetabular index and centre-edge angle were measured on plain radiographs at the last follow-up. The presence of AVN according to Kalamchi and McEwen's classification was assessed. We retrospectively analyzed the associations among abduction angles, hip joint distances, radiographic parameters, AVN and final outcomes, exploring the relationship between hip joint abduction angle and AVN rate.

RESULTS

The mean age at the time of CR was 14.4 months SD 5.5 (6 to 28), and the mean follow-up was 26.2 months SD 8.1 (12.4 to 41.7). The mean hip abduction angle was 70.2° SD 7.2° (53° to 85°) on the dislocated side and 63.7° SD 8.8° (40° to 82°) on the normal side; the mean hip joint distance was 5.1 mm SD 1.9 (1.3 to 9.1) on the dislocated side and 2.2 mm SD 0.6 on the normal side (1.3 to 3.3). Eight of 59 hips (13.6%) developed AVN. Neither the amount of abduction nor hip joint distance increased the AVN rate (p = 0.97 and p = 0.65, respectively) or the dislocation rate (p = 0.38 and p = 0.14, respectively).

CONCLUSION

Abduction angle up to 70.2° following CR did not increase the AVN rate in children aged six to 28 months with late-detected DDH treated by CR.

LEVEL OF EVIDENCE

III.

Calcium signals that determine vascular resistance

Small arteries in the body control vascular resistance, and therefore, blood pressure and blood flow. Endothelial and smooth muscle cells in the arterial walls respond to various stimuli by altering the vascular resistance on a moment to moment basis. Smooth muscle cells can directly influence arterial diameter by contracting or relaxing, whereas endothelial cells that line the inner walls of the arteries modulate the contractile state of surrounding smooth muscle cells. Cytosolic calcium is a key driver of endothelial and smooth muscle cell functions. Cytosolic calcium can be increased either by calcium release from intracellular stores through IP3 or ryanodine receptors, or the influx of extracellular calcium through ion channels at the cell membrane. Depending on the cell type, spatial localization, source of a calcium signal, and the calcium-sensitive target activated, a particular calcium signal can dilate or constrict the arteries. Calcium signals in the vasculature can be classified into several types based on their source, kinetics, and spatial and temporal properties. The calcium signaling mechanisms in smooth muscle and endothelial cells have been extensively studied in the native or freshly isolated cells, therefore, this review is limited to the discussions of studies in native or freshly isolated cells. This article is categorized under: Biological Mechanisms > Cell Signaling Laboratory Methods and Technologies > Imaging Models of Systems Properties and Processes > Mechanistic Models.

[Construction of prognostic model and identification of prognostic biomarkers based on the expression of long non-coding RNA in bladder cancer via bioinformatics]

OBJECTIVE

To construct the prognostic model and identify the prognostic biomarkers based on long non-coding RNA (lncRNA) in bladder cancer.

METHODS

The lncRNA expression data and corresponding clinical data of bladder cancer were collected from The Cancer Genome Atlas (TCGA) database. The software Perl and R, and R packages were used for data integration, extraction, analysis and visualization. Detailly, R package "edgeR" was utilized to screen differentially expressed lncRNA in bladder cancer tissues compared with the normal bladder samples. The univariate Cox regression and the least absolute shrinkage and selection operator (Lasso) regression were performed to identify key lncRNA that were utilized to construct the prognostic model by the multivariate Cox regression. According to the median value of the risk score, all patients were divided into the high-risk group and low-risk group to perform the Kaplan-Meier (K-M) survival curves, receiver operating characteristic (ROC) curve and C-index, estimating the prognostic power of the prognostic model. In addition, the hazard ratio (HR) and 95% confidence interval (CI) of each key lncRNA were also calculated by the multivariate Cox regression. Moreover, we performed the K-M survival analysis for each significant key lncRNA from the result of the multivariate Cox regression.

RESULTS

A total of 691 lncRNA were identified as differentially expressed lncRNA, and 35 lncRNA signatures were initially considered associated with the prognosis of bladder cancer, where in 23 lncRNA were identified as key lncRNA associated with the prognosis. The overall survival time in years of the low-risk group was obviously longer than that of the high-risk group [(2.85±2.72) years vs. (1.58±1.51) years, P<0.001]. The area under the ROC curve (AUC) was 0.813 (3-year survival) and 0.778 (5-year survival) respectively, and the C-index was 0.73. In addition, HR and 95%CI of each key lncRNA were calculated by the multivariate Cox regression and 11 lncRNA were significant. Furthermore, K-M survival analysis revealed the independent prognostic value of 3 lncRNA, including AL589765.1 (P=0.004), AC023824.1 (P=0.022)and PKN2-AS1 (P=0.016).

CONCLUSION

The present study successfully constructed the prognostic model based on the expression level of 23 lncRNA and finally identified one protective prognostic biomarker AL589765.1, and two adverse prognostic biomarkers including AC023824.1 and PKN2-AS1 in bladder cancer.