Development of novel layered polyglycolic acid sheet for regeneration of critical-size defect in rat trachea.

OBJECTIVES: Polyglycolic acid (PGA) sheets are difficult to adapt to the central airway because of poor durability against high air pressure. Therefore, we developed a novel layered PGA material to cover the central airway and examined its morphologic traits and functional performance as a potential tracheal replacement. METHODS: A critical-size defect in rat cervical tracheas was covered with the material. Morphologic changes were bronchoscopically and pathologically evaluated. Functional performance was evaluated by regenerated ciliary area, ciliary beat frequency and ciliary transport function determined by measuring the moving distance of microspheres dropped onto the trachea (µm/s). The evaluation time points were 2 weeks, 1 month, 2 months and 6 months after surgery (n = 5, respectively). RESULTS: Forty rats underwent implantation, and all survived. Histological examination confirmed ciliated epithelization on the luminal surface after 2 weeks. Neovascularization was observed after 1 month, tracheal glands after 2 months and chondrocyte regeneration after 6 months. Although the material was gradually replaced by self-organization, tracheomalacia was not bronchoscopically observed at any time point. The area of regenerated cilia significantly increased between 2 weeks and 1 month (12.0% vs 30.0%; P = 0.0216). The median ciliary beat frequency significantly improved between 2 weeks and 6 months (7.12 vs 10.04 Hz; P = 0.0122). The median ciliary transport function was significantly improved between 2 weeks and 2 months (5.16 vs 13.49 µm/s; P = 0.0216). CONCLUSIONS: The novel PGA material showed excellent biocompatibility and tracheal regeneration both morphologically and functionally 6 months after tracheal implantation.

Feasibility study of a novel wireless localization technique using radiofrequency identification markers for small and deeply located lung lesions.

Objectives: To evaluate the safety and efficacy of a novel wireless localization technique that uses radiofrequency identification markers for small and deep lung lesions. Methods: Preliminary use of the device was retrospectively evaluated in 2 Japanese centers. Under general anesthesia, a marker was placed as close as possible to the tumor via computed tomography-guided bronchoscopy in a hybrid operation theater. Surgeons located the marker without lung palpation using a detection probe the tone of which changed to indicate the marker-probe distance. Efficacy was defined as functional marker placement (bronchoscopy time and marker position) and deep margin distance. Results: Twelve markers were placed for 11 lesions (mean size, 6.8 ± 2.7 mm) located at a mean depth from the pleura of 11.4 ± 8.4 mm (range = 0-26.0 mm). Of 12 markers, 7 markers (58.3%) were placed within 10 mm from the lesion in 25.5 ± 14.4 minutes. For the 11 wedge resections, markers were placed at a mean distance of 6.7 mm (range, 0-13.0 mm) from the lesion and a mean distance of 14.4 mm (range, 3.0-42.0 mm) from the pleura. All markers were recovered without complications, and all tumors were resected with negative margins. For 5 lesions >10 mm deep to the pleura (mean depth, 18.9 ± 5.5 mm; range, 11.0-26.0 mm), the median depth of the surgical margin was 11.6 ± 2.1 mm (range, 9.0-14.0 mm). Conclusions: Radiofrequency identification marking was safe and precisely localized small lung lesions, including their depth.

Successful Leadless Pacemaker Implantation in an Elderly Patient With Dextrocardia and Situs Inversus.

Leadless pacemaker is indicated in patients with symptomatic bradycardia as an alternative therapy when transvenous pacemaker implantation is considered difficult or at high risk. The experience of implanting leadless pacemaker in patients with dextrocardia and situs inversus is limited. A 94-year-old male was transferred to our hospital due to advanced atrio-ventricular block with episode of syncope. Chest radiograph and computed tomography revealed dextrocardia with situs inversus. Emergency cardiac catheterization was performed and a temporary pacemaker was inserted, but the patient removed it due to delirium. So, a leadless pacemaker was implanted to him. Shorter time of bed-rest after the implantation and shorter hospital stay would be beneficial of implanting a leadless pacemaker. Precise anatomical evaluation would be important to perform implantation efficiently and safely.

Group 2 Innate Lymphoid Cells Exacerbate Amebic Liver Abscess in Mice.

Entamoeba histolytica, a protozoan parasite in the lumen of the human large intestine, occasionally spreads to the liver and induces amebic liver abscesses (ALAs). Upon infection with E. histolytica, high levels of type 2 cytokines are induced in the liver early after infection. However, the sources and functions of these initial type 2 cytokines in ALA formation remain unclear. In this study, we examined the roles of group 2 innate lymphoid cells (ILC2s) in ALA formation. Hepatic ILC2 numbers were significantly increased and they produced robust levels of IL-5. The in vivo transfer of ILC2s into Rag2-/-common γ chain (γc)-/- KO mice aggravated ALA formation accompanied by eosinophilia and neutrophilia. Furthermore, IL-33-deficient mice and IL-5-neutralized mice had less ALA formations. These results suggest that ILC2s contribute to exacerbating the pathogenesis of ALA by producing early type 2 cytokines and promoting the accumulation of eosinophils and neutrophils in the liver.

The T Cell Antigen Receptor α Transmembrane Domain Coordinates Triggering through Regulation of Bilayer Immersion and CD3 Subunit Associations.

Initial molecular details of cellular activation following αßT cell antigen receptor (TCR) ligation by peptide-major histocompatibility complexes (pMHC) remain unexplored. We determined the nuclear magnetic resonance (NMR) structure of the TCRα subunit transmembrane (TM) domain revealing a bipartite helix whose segmentation fosters dynamic movement. Positively charged TM residues Arg251 and Lys256 project from opposite faces of the helix, with Lys256 controlling immersion depth. Their modification caused stepwise reduction in TCR associations with CD3ζζ homodimers and CD3εγ plus CD3εδ heterodimers, respectively, leading to an activated transcriptome. Optical tweezers revealed that Arg251 and Lys256 mutations altered αßTCR-pMHC bond lifetimes, while mutations within interacting TCRα connecting peptide and CD3δ CxxC motif juxtamembrane elements selectively attenuated signal transduction. Our findings suggest that mechanical forces applied during pMHC ligation initiate T cell activation via a dissociative mechanism, shifting disposition of those basic sidechains to rearrange TCR complex membrane topology and weaken TCRαß and CD3 associations.

Regulation of thymocyte trafficking by Tagap, a GAP domain protein linked to human autoimmunity.

Multiple autoimmune pathologies are associated with single-nucleotide polymorphisms of the human gene TAGAP, which encodes TAGAP, a guanosine triphosphatase (GTPase)-activating protein. We showed in mice that Tagap-mediated signaling by the sema3E/plexin-D1 ligand-receptor complex attenuates thymocytes' adhesion to the cortex through their ß1-containing integrins. By promoting thymocyte detachment within the cortex of the thymus, Tagap-mediated signaling enabled their translocation to the medulla, which is required for continued thymic selection. Tagap physically interacted with the cytoplasmic domain of plexin-D1 and directly stimulated the activity and signaling of the GTPase RhoA. In addition, Tagap indirectly mediated the activation of Cdc42 in response to the binding of sema3E to plexin-D1. Both RhoA and Cdc42 are key mediators of cytoskeletal and integrin dynamics in thymocytes. Knockdown of Tagap in mice suppressed the sema3E- and plexin-D1-mediated release of thymocytes that adhered within the cortex through ß1-containing integrins. This suppression led to the impaired translocation of thymocytes from the cortex to the medulla and resulted in the formation of ectopic medullary structures within the thymic cortex. Our results suggest that TAGAP variation modulates the risk of autoimmunity by altering thymocyte migration during thymic selection.

TCR-pMHC encounter differentially regulates transcriptomes of tissue-resident CD8 T cells.

To investigate the role of TCR-pMHC interaction in regulating lung CD8 tissue-resident T cell (TR ) differentiation, polyclonal responses were compared against NP366-374 /Db and PA224-233 /Db , two immunodominant epitopes that arise during influenza A infection in mice. Memory niches distinct from iBALTs develop within the lamina propria, supporting CD103+ and CD103- CD8 TR generation and intraepithelial translocation. Gene set enrichment analysis (GSEA) and weighted gene co-expression network analysis (WGCNA) identify dominant TCR, adherens junction, RIG-I-like and NOD-like pattern recognition receptor as well as TGF-ß signaling pathways and memory signatures among PA224-233 /Db T cells consistent with T resident memory (TRM ) status. In contrast, NP366-374 /Db T cells exhibit enrichment of effector signatures, upregulating pro-inflammatory mediators even among TRM . While NP366-374 /Db T cells manifest transcripts linked to canonical exhaustion pathways, PA224-233 /Db T cells exploit P2rx7 purinoreceptor attenuation. The NP366-374 /Db CD103+ subset expresses the antimicrobial lactotransferrin whereas PA224-233 /Db CD103+ utilizes pore-forming mpeg-1, with <22% of genes correspondingly upregulated in CD103+ (or CD103- ) subsets of both specificities. Thus, TCR-pMHC interactions among TR and antigen presenting cells in a tissue milieu strongly impact CD8 T cell biology.

Role of non-electrocardiogram-gated contrast-enhanced computed tomography in the diagnosis of acute coronary syndrome.

Non-electrocardiogram-gated contrast-enhanced computed tomography (non-ECG-gated CT) is available in most hospitals where patients with chest and/or back pain are admitted to the emergency department. Although it has been established as the initial diagnostic imaging modality for acute aortic dissection (AAD) and pulmonary thromboembolism (PE), its diagnostic ability for acute coronary syndrome (ACS) in the emergency department has not been elucidated. We retrospectively investigated 154 consecutive patients who required non-ECG-gated CT to differentiate AAD and PE in the emergency department, but had no evidence of them on CT. Furthermore, a subanalysis was performed in the patients who were subsequently suspected of ACS and underwent emergent invasive coronary angiography followed by CT. We evaluated left ventricular enhancement to detect myocardial perfusion deficit by calculating Hounsfield units, and the results were compared with ultimate diagnoses and angiography findings. A perfusion deficit was detected in 43 patients, among whom 26 were ultimately diagnosed with acute myocardial infarction (AMI); 24 patients required emergent revascularization. The subanalysis indicated that perfusion abnormalities corresponded with the territory of the culprit artery in all except one patient. In the remaining 111 patients without perfusion deficit, only two required emergent revascularization, and their levels of creatine kinase MB were not elevated. The sensitivity, specificity, and positive and negative predictive values of non-ECG-gated CT in predicting AMI/emergent revascularization were 93 %, 87 %, 61 %, and 98 %/92 %, 85 %, 56 %, and 98 %, respectively. Non-ECG-gated CT facilitates the diagnosis of ACS and the decision on emergent catheterization, providing information on the ischemic myocardial area by detection of a localized decrease in left ventricular enhancement.

Left atrial myxoma detected after an initial diagnosis of polymyalgia rheumatica.

We herein report the case of a 69-year-old woman with left atrial myxoma detected following treatment with glucocorticoids for an initial diagnosis of polymyalgia rheumatica (PMR). The glucocorticoids markedly improved the patient's symptoms, and the tumor was excised after rapidly tapering the glucocorticoid dose. The PMR-like symptoms did not recur and the inflammatory marker levels returned to normal after surgery. The patient's clinical course indicated that the initial PMR-like symptoms were entirely caused by the left atrial myxoma. This case demonstrates that glucocorticoid treatment for suspected PMR can mask the symptoms of myxoma, leading to a delay in diagnosis.

Detection of periodontal bacteria in thrombi of patients with acute myocardial infarction by polymerase chain reaction.

BACKGROUNDS: Numerous reports have demonstrated that periodontal bacteria are present in plaques from atherosclerotic arteries. Although periodontitis has recently been recognized as a risk factor for coronary artery disease, the direct relationship between periodontal bacteria and coronary artery disease has not yet been clarified. It has been suggested that these bacteria might contribute to inflammation and plaque instability. We assumed that if periodontal bacteria induce inflammation of plaque, the bacteria would be released into the bloodstream when vulnerable plaque ruptures. To determine whether periodontal bacteria are present in thrombi at the site of acute myocardial infarction, we tried to detect periodontal bacteria in thrombi of patients with acute myocardial infarction by polymerase chain reaction (PCR). METHODS: We studied 81 consecutive adults with ST-segment elevation acute myocardial infarction who underwent primary percutaneous coronary intervention (PCI). All patients underwent removal of thrombus with aspiration catheters at the beginning of percutaneous coronary intervention, and a small sample of thrombus was obtained for PCR. RESULTS: The detection rates of periodontal bacteria by PCR were 19.7% for Aggregatibacter actinomycetemcomitans, 3.4% for Porphyromonas gingivalis, and 2.3% for Treponema denticola. CONCLUSIONS: Three species of periodontal bacteria were detected in the thrombi of patients with acute myocardial infarction. This raises the possibility that such bacteria are latently present in plaque and also suggests that these bacteria might have a role in plaque inflammation and instability.

Autoimmunity against M2muscarinic acetylcholine receptor induces myocarditis and leads to a dilated cardiomyopathy-like phenotype.

Patients with dilated cardiomyopathy (DCM) often have autoantibodies against cardiac antigens including the M(2) muscarinic acetylcholine receptor (M(2)R). To elucidate the role of autoimmunity against M(2)R in disease development, we induced an immune response against M(2)R by adoptive transfer into Rag2(-/-) mice of splenocytes from M(2)R(-/-) mice immunized with a recombinant M(2)R protein. T lymphocytes transiently infiltrated the heart in recipient mice followed by morphological changes in cardiomyocytes. These mice produced IgG antibodies against M(2)R, which bound to cardiomyocytes in vivo and decreased the amplitude of calcium signals in isolated rat cardiomyocytes in vitro. Recipient mice showed increased heart weights associated with increased intraventricular diameter, decreased systolic function, and increased action potential duration, which are characteristics of DCM. Our results suggest that myocarditis and DCM associated with the presence of anti-M(2)R antibodies are autoimmune diseases with a risk of progressing to the terminal stage. Our mouse model will be useful in the analysis of the molecular mechanisms of disease progression and the development of new therapies for DCM.

Specific immunoadsorption therapy using a tryptophan column in patients with refractory heart failure due to dilated cardiomyopathy.

BACKGROUND: Certain cardiac-specific autoantibodies found in patients with dilated cardiomyopathy (DCM) play a role in mediating myocardial damage and fatal ventricular arrhythmias resulting in sudden cardiac death. Immunoadsorption therapy (IA) is one of the therapeutic tools to remove such autoantibodies. Clinical studies from Germany have shown that nonspecific IA using columns loaded by sheep antihuman IgG or protein A improved hemodynamic data and affected favorably cardiac function and survival in patients with heart failure (HF) due to DCM. The goal of this study is to determine if IA therapy using the high-profile tryptophan column, which has high affinity for IgG3 subclass, affects favorably cardiac function in patients with severe HF who are refractory to conventional therapy. METHODS AND RESULTS: IA therapy was conducted in 16 patients with DCM (age 53 ± 4, male 8, New York Heart Association functional class III/IV, mean ejection fraction 18 ± 2%). Study subjects had autoantibodies directed against either ß1-adrenergic or M2-muscarinic receptors. Plasma brain natriuretic peptide levels were significantly decreased after IA (P = 0.016). Plasma inflammatory cytokines including interleukin-6 and tumor necrosis factor-α did not change after each session of IA. Six-minute walk distance was significantly increased after IA (P = 0.01). Left ventricular ejection fraction increased by 3% 3 months after IA (P = 0.039). CONCLUSIONS: Our initial experience demonstrated safety and short-term efficacy of IA using a new IgG3-specific tryptophan column for patients with advanced HF due to DCM. Long-term follow-up is needed to confirm the effects on cardiac function and morbidity/mortality in such patients.

A pilot study on the role of autoantibody targeting the beta1-adrenergic receptor in the response to beta-blocker therapy for congestive heart failure.

BACKGROUND: Autoantibodies directed against the beta1-adrenergic receptor exert agonist-like actions by inducing receptor uncoupling and cause myocardial damage as well as fatal ventricular arrhythmias. Previous studies have shown that beta-blockers can modulate these actions of the autoantibodies. We investigated the influence of such autoantibodies in patients with congestive heart failure (CHF) receiving beta-blocker therapy. METHODS AND RESULTS: Eighty-two CHF patients were randomly assigned to treatment with metoprolol or carvedilol for 16 weeks. Autoantibodies were detected in 20 patients (24%) by enzyme-linked immunosorbent assay. Left ventricular function in response to beta-blocker therapy did not differ significantly by the presence of the autoantibody in global analysis. However, changes of the left ventricular end-diastolic dimension (P = .04), end-systolic dimension (P < .01), and ejection fraction on radionuclide ventriculography (P = .02) were significantly larger in autoantibody-positive patients than antibody-negative patients. Changes in the plasma level of brain natriuretic peptide tended to be larger in autoantibody-positive patients (P = .09). The increase of heart rate normalized by the increase of plasma norepinephrine during exercise (an index of adrenergic responsiveness) showed a greater decrease in autoantibody-positive patients than autoantibody-negative patients (P = .035). CONCLUSION: Our data suggest that beta-blocker therapy might be more effective in CHF patients with autoantibodies targeting the beta1-adrenergic receptor.

Comparison of the effects of carvedilol and metoprolol on exercise ventilatory efficiency in patients with congestive heart failure.

BACKGROUND: The slope of the relationship between ventilation and carbon dioxide production (VE/VCO2 slope), obtained during symptom-limited ramp exercise testing, reflects exercise ventilatory efficiency. Importantly, the VE/VCO2 slope is related to prognosis in patients with congestive heart failure (CHF). The aim of the present study was to determine the relationship between the institution of beta-blockers, carvedilol or metoprolol, and the VE/VCO2 slope during exercise in patients with CHF. METHODS AND RESULTS: Fifty-seven patients with New York Heart Association functional class II or III with a radionuclide left ventricular ejection fraction (LVEF) of less than 40% received carvedilol or metoprolol in a randomized fashion. The VE/VCO2 slope, LVEF and plasma brain natriuretic peptide (BNP) concentration were determined before and after 16 weeks of treatment. LVEF improved (p<0.01), but the VE/VCO2 slope and BNP did not. A significant improvement in the VE/VCO2 slope was observed in patients with LVEF <29% or BNP >63 pg/ml (respective baseline median values) (p<0.05, p<0.05). In patients with BNP >63 pg/ml, the improvement effect on the VE/VCO2 slope with carvedilol was significantly greater than that with metoprolol (p<0.05) and a significant improvement in the VE/VCO2 slope was observed only in those who took carvedilol (p<0.01). CONCLUSIONS: The VE/VCO2 slope was not improved after beta-blocker therapy in any of the patients. However, it did improve in patients with a lower LVEF or higher BNP level at baseline, and carvedilol was more effective than metoprolol in improving the VE/VCO2 slope in patients with higher BNP levels at baseline.

Effects of beta-blocker therapy on high sensitivity c-reactive protein, oxidative stress, and cardiac function in patients with congestive heart failure.

BACKGROUND: It is uncertain whether beta-blocker therapy affects serum C-reactive protein (CRP) level in patients with congestive heart failure (CHF). We attempted to determine if beta-blocker therapy decreases serum CRP production and to correlate the production with biomarkers and cardiac function in such patients. METHODS AND RESULTS: Fifty-two patients with mild to moderate CHF with a left ventricular ejection fraction (EF) <40% were enrolled. They were randomly assigned to metoprolol or carvedilol treatment groups. The CRP concentration decreased significantly in patients with higher baseline CRP concentration, but not in those with lower baseline CRP concentrations. There was an inverse correlation between DeltaCRP and DeltaEF 16 weeks after the start of beta-blocker therapy for patients with higher baseline CRP concentrations. In patients with higher baseline concentrations, CRP decreased in patients who received carvedilol, but not in those who received metoprolol. Plasma lipid peroxide (LPO) concentration significantly decreased, and there was an inverse correlation between DeltaCRP and DeltaLPO 16 weeks after the start of therapy. CONCLUSIONS: Administration of beta-blockers is associated with attenuation of inflammatory marker in certain patients with CHF. The antioxidant effects of beta-blockers, especially carvedilol, may play a role in mediating the phenomenon.

Carvedilol exerts more potent antiadrenergic effect than metoprolol in heart failure.

BACKGROUND: It is still uncertain whether or not there is a difference between metoprolol and carvedilol for the treatment of congestive heart failure. We attempted to determine the difference between the two beta-blockers in terms of their antiadrenergic effect during exercise in patients with heart failure and their efficacy based on the baseline plasma brain natriuretic peptide concentration. METHODS: Fifty-three patients with mild to moderate heart failure with a radionuclide left ventricular ejection fraction <40% received open label metoprolol or carvedilol in a randomized fashion. The increase in the heart rate normalized to the increase in the plasma norepinephrine concentration during exercise, was calculated as an index of adrenergic responsiveness during exercise. RESULTS: The increase in heart rate normalized by the increase in plasma norepinephrine concentration, decreased after the initiation of beta-blockers in the carvedilol group, but not in the metoprolol group. The change in cardiac function was more favorable for carvedilol than metoprolol in patients who exhibited a higher baseline brain natriuretic peptide concentration. CONCLUSIONS: Carvedilol exerts a more potent antiadrenergic effect than metoprolol during stress in patients with mild to moderate heart failure. Carvedilol appears to be more efficacious than metoprolol in patients who exhibit higher baseline brain natriuretic peptide concentrations. These differences should be kept in mind when selecting appropriate pharmacologic agents in the treatment of heart failure.

Brain natriuretic peptide response is heterogeneous during beta-blocker therapy for congestive heart failure.

BACKGROUND: Plasma brain natriuretic peptide (BNP) levels are useful marker to guide medical treatment in patients with congestive heart failure (CHF). We tested the hypothesis that the plasma BNP concentration would be a useful marker of beta-blocker therapy for CHF. METHODS AND RESULTS: Eighty-four patients with New York Heart Association class II-IV CHF and a left ventricular ejection fraction (LVEF) <40% were treated with beta-blockers, including metoprolol and carvedilol, for at least 16 weeks. End-diastolic and end-systolic dimensions decreased, and radionuclide LVEF increased 4 weeks after introduction of beta-blockers (early phase). LV end-diastolic and end-systolic dimensions both decreased, and LVEF increased 16 to 48 weeks after the therapy (late phase). However, the BNP concentration did not change during the observation period. Overall LV function improved in all 4 subgroups divided according to the baseline BNP levels. CONCLUSIONS: Plasma BNP concentration is not a sensitive marker of successful beta-blocker therapy for CHF.