Influence of Pathophysiological Patterns of Coronary Artery Disease on Immediate Percutaneous Coronary Intervention Outcomes.

BACKGROUND: Diffuse coronary artery disease (CAD) impacts the safety and efficacy of percutaneous coronary intervention (PCI). Pathophysiological CAD patterns can be quantified using fractional flow reserve (FFR) pullbacks incorporating the pullback pressure gradient (PPG) calculation. This study aimed to establish the capacity of PPG to predict optimal revascularisation and procedural outcomes. METHODS: This prospective, investigator-initiated, single-arm, multicentre study enrolled patients with at least one epicardial lesion with an FFR ≤ 0.80 scheduled for PCI. Manual FFR pullbacks were employed to calculate PPG. The primary outcome of optimal revascularisation was defined as a post-PCI FFR ≥ 0.88. RESULTS: 993 patients with 1044 vessels were included. The mean FFR was 0.68 ± 0.12, PPG 0.62 ± 0.17, and post-PCI FFR 0.87 ± 0.07. PPG was significantly correlated with the change in FFR after PCI (r=0.65, 95% CI 0.61-0.69, p<0.001) and demonstrated excellent predicted capacity for optimal revascularisation (AUC 0.82, 95% CI 0.79-0.84, p<0.001). Conversely, FFR alone did not predict revascularisation outcomes (AUC 0.54, 95% CI 0.50-0.57). PPG influenced treatment decisions in 14% of patients, redirecting them from PCI to alternative treatment modalities. Periprocedural myocardial infarction occurred more frequently in patients with low PPG (<0.62) compared to those with focal disease (OR 1.71, 95% CI: 1.00-2.97). CONCLUSIONS: Pathophysiological CAD patterns distinctly affect the safety and effectiveness of PCI. The PPG showed an excellent predictive capacity for optimal revascularisation and demonstrated added value compared to a FFR measurement.

Is ischemic stimulus involved for J wave augmentation during coronary angiography and intracoronary administration of normal saline?

BACKGROUND: J waves may be augmented by coronary angiography (CAG) or intracoronary drug administration but the underlying mechanism is unknown. PURPOSE: The effect of intracoronary normal saline (NS) on J waves were investigated. PATIENTS AND METHODS: After the standard CAG using iopamidol (IopamiroR Inj), NS was injected into the right coronary artery in 10 patients with and eight patients without J waves at the baseline. The 12-lead ECG was monitored, stored on a computer and retrieved later for measurement of the J wave amplitude before or during the coronary interventions. RESULTS: J waves in leads II, III and aVF at baseline increased significantly in each lead during the right CAG and NS injection into the right coronary artery. The J wave changes were similar between the two interventions and distinct similar alterations were observed in the QRS complex. We postulated that the ischemic myocardium that was induced during CAG or intracoronary NS administration slowed the conduction velocity of depolarization in the perfusion territory and delayed the timing of J waves to appear. Then, the delayed appearance of J waves would be less opposed by electromotive force from other areas resulting in augmentation. CONCLUSION: J wave augmentation was observed during CAG and intracoronary NS administration. As a mechanism of augmentation, we postulated that contrast media and NS induce myocardial ischemia and delay the timing of J waves to a point of less opposition by electromotive force from other areas. HIGHLIGHTS: J wave augmentation has been reported during intracoronary injection of contrast media or drugs. The present study confirmed that normal saline alone was able to augment J waves. Mechanistically, coronary interventions using anoxic solutions can cause regional myocardial ischemia and reduce the conduction velocity of depolarization. Then, delayed J waves are less opposed by the electromotive force from remote areas which leads to augmentation. When a drug is diluted in normal saline and given intracoronarily, changes in J waves can be due to normal saline. The pathophysiological and clinical significance of J waves augmented during coronary interventions need to be established.

Microvascular resistance reserve: diagnostic and prognostic performance in the ILIAS registry.

AIMS: The microvascular resistance reserve (MRR) was introduced as a means to characterize the vasodilator reserve capacity of the coronary microcirculation while accounting for the influence of concomitant epicardial disease and the impact of administration of potent vasodilators on aortic pressure. This study aimed to evaluate the diagnostic and prognostic performance of MRR. METHODS AND RESULTS: A total of 1481 patients with stable symptoms and a clinical indication for coronary angiography were included from the global ILIAS Registry. MRR was derived as a function of the coronary flow reserve (CFR) divided by the fractional flow reserve (FFR) and corrected for driving pressure. The median MRR was 2.97 [Q1-Q3: 2.32-3.86] and the overall relationship between MRR and CFR was good [correlation coefficient (Rs) = 0.88, P < 0.005]. The difference between CFR and MRR increased with decreasing FFR [coefficient of determination (R2) = 0.34; Coef.-2.88, 95% confidence interval (CI): -3.05--2.73; P < 0.005]. MRR was independently associated with major adverse cardiac events (MACE) at 5-year follow-up [hazard ratio (HR) 0.78; 95% CI 0.63-0.95; P = 0.024] and with target vessel failure (TVF) at 5-year follow-up (HR 0.83; 95% CI 0.76-0.97; P = 0.047). The optimal cut-off value of MRR was 3.0. Based on this cut-off value, only abnormal MRR was significantly associated with MACE and TVF at 5-year follow-up in vessels with functionally significant epicardial disease (FFR <0.75). CONCLUSION: MRR seems a robust indicator of the microvascular vasodilator reserve capacity. Moreover, in line with its theoretical background, this study suggests a diagnostic advantage of MRR over other indices of vasodilatory capacity in patients with hemodynamically significant epicardial coronary artery disease.

Rationale and design of the pullback pressure gradient (PPG) global registry.

INTRODUCTION: Diffuse disease has been identified as one of the main reasons leading to low post-PCI fractional flow reserve (FFR) and residual angina after PCI. Coronary pressure pullbacks allow for the evaluation of hemodynamic coronary artery disease (CAD) patterns. The pullback pressure gradient (PPG) is a novel metric that quantifies the distribution and magnitude of pressure losses along the coronary artery in a focal-to-diffuse continuum. AIM: The primary objective is to determine the predictive capacity of the PPG for post-PCI FFR. METHODS: This prospective, large-scale, controlled, investigator-initiated, multicenter study is enrolling patients with at least 1 lesion in a major epicardial vessel with a distal FFR ≤ 0.80 intended to be treated by PCI. The study will include 982 subjects. A standardized physiological assessment will be performed pre-PCI, including the online calculation of PPG from FFR pullbacks performed manually. PPG quantifies the CAD pattern by combining several parameters from the FFR pullback curve. Post-PCI physiology will be recorded using a standardized protocol with FFR pullbacks. We hypothesize that PPG will predict optimal PCI results (post-PCI FFR ≥ 0.88) with an area under the ROC curve (AUC) ≥ 0.80. Secondary objectives include patient-reported and clinical outcomes in patients with focal vs. diffuse CAD defined by the PPG. Clinical follow-up will be collected for up to 36 months, and an independent clinical event committee will adjudicate events. RESULTS: Recruitment is ongoing and is expected to be completed in the second half of 2023. CONCLUSION: This international, large-scale, prospective study with pre-specified powered hypotheses will determine the ability of the preprocedural PPG index to predict optimal revascularization assessed by post-PCI FFR. In addition, it will evaluate the impact of PPG on treatment decisions and the predictive performance of PPG for angina relief and clinical outcomes.

Angiography-derived functional assessment of left main coronary stenoses.

OBJECTIVES: We aimed to evaluate the diagnostic accuracy of quantitative flow ratio (QFR) in left main (LM) coronary stenoses, using Fractional Flow Reserve (FFR) as reference. BACKGROUND: QFR has demonstrated a high accuracy in determining the functional relevance of coronary stenoses in non-LM. However, there is an important paucity of data regarding its diagnostic value in the specific anatomical subset of LM disease. METHODS: This is a retrospective, observational, multicenter, international, and blinded study including patients with LM stenoses. Cases with significant ostial LM disease were excluded. QFR was calculated from conventional angiograms at blinded fashion with respect to FFR. RESULTS: Sixty-seven patients with LM stenoses were analyzed. Overall, LM had intermediate severity, both from angiographic (diameter stenosis [%DS] 43.8 ± 11.1%) and functional perspective (FFR 0.756 ± 0.105). Mean QFR was 0.733 ± 0.159. Correlation between QFR and FFR was moderate (r = 0.590). Positive and negative predictive value, sensitivity and specificity were 85.4%, 64%, 85.4%, and 69.6% respectively. Classification agreement of QFR and FFR in terms of functional stenosis severity was 78.1%. Area under the receiver operating characteristics of QFR using FFR as reference was 0.82 [95% confidence interval [CI], 0.71-0.93], and significantly better than angiographic evaluation including %DS (area under the receiver-operating characteristic curve [AUC] 0.45 [95% CI, 0.32-0.58], p < 0.001) and minimum lumen diameter (AUC 0.60 [95% CI, 0.47-0.74], p < 0.001). CONCLUSIONS: Compared with FFR, QFR has acceptable diagnostic performance in determining the functional relevance of LM stenosis, being better than conventional angiographic assessment. Nonetheless, caution should be taken when applying functional angiography techniques for the assessment of LM stenosis given its particular anatomical characteristics.

Dipeptidyl peptidase-4 inhibitors reduce the incidence of first cardiovascular events in Japanese diabetic patients.

BACKGROUND: Dipeptidyl Peptidase-4 (DPP-4) inhibitors do not suppress cardiovascular events in diabetic patients with a history of cardiovascular disease. However, the effect of DPP-4 inhibitors on cardiovascular events in Japanese diabetic patients is unclear. Therefore, we investigated whether DPP-4 inhibitors alter the incidence of cardiovascular events in Japanese diabetic patients without a history of cardiovascular events. METHODS: The Japanese Primary Prevention of Atherosclerosis with Aspirin for Diabetes (JPAD) trial was a multicenter, prospective, randomized, open label, blinded, end-point study conducted from 2002 to 2008. After completion of the JPAD trial, we followed up the patients until 2019. Patients who had had a cardiovascular event by the 2013 follow-up were excluded from the study. JPAD patients were divided into a DPP-4 group and a non-DPP-4 group based on whether they were taking DPP-4 inhibitors at the 2013 follow-up because few patients took DPP-4 inhibitors before 2013. We investigated the incidence of cardiovascular events consisting of coronary events, cerebrovascular events, heart failure requiring hospitalization, and aortic and peripheral vascular disease in 1099 JPAD patients until 2019. RESULTS: During the observation period from 2013 to 2019, 37 (7%) first cardiovascular events occurred in the DPP-4 group (n = 518) and 66 (11%) in the non-DPP-4 group (n = 581). The incidence of cardiovascular events was significantly lower in the DPP-4 group than in the non-DPP-4 group (Log-Rank P = 0.0065). Cox proportional hazards model analysis revealed that the use of DPP-4 inhibitors (hazard ratio 0.65; 95% confidence interval 0.43-0.98; P = 0.038) was an independent factor after adjustment for age ≥ 65 years, hypertension, statin usage, and insulin usage. CONCLUSIONS: Our findings have demonstrated that the use of DPP-4 inhibitors may be associated with a reduced incidence of first cardiovascular events in Japanese diabetic patients. The results require confirmation in randomized controlled trials.

Impact of stenosis resistance and coronary flow capacity on fractional flow reserve and instantaneous wave-free ratio discordance: a combined analysis of DEFINE-FLOW and IDEAL.

BACKGROUND: The pressure-derived parameters fractional flow reserve (FFR) and the emerging instantaneous wave-free ratio (iFR) are the most widely applied invasive coronary physiology indices to guide revascularisation. However, approximately 15-20% of intermediate stenoses show discordant FFR and iFR, and therapeutical consensus is lacking. AIMS: We sought to associate hyperaemic stenosis resistance index, coronary flow reserve (CFR) and coronary flow capacity (CFC) to FFR/iFR discordance. METHODS: We assessed pressure and flow measurements of 647 intermediate lesions (593 patients) of two multi-centre international studies. RESULTS: FFR and iFR were discordant in 15% of all lesions (97 out of 647). FFR+/iFR- lesions had similar hyperaemic average peak velocity (hAPV), CFR and CFC as FFR-/iFR- lesions, whereas FFR-/iFR+ lesions had similar hAPV, CFR and CFC as FFR+/iFR+ lesions (p > 0.05 for all). FFR+/iFR- lesions were associated with lower baseline stenosis resistance, but not hyperaemic stenosis resistance, compared with FFR-/iFR+ lesions (p < 0.001). CONCLUSIONS: Discordance with FFR+/iFR- is characterised by maximal flow values, CFR, and CFC patterns similar to FFR-/iFR- concordance that justifies conservative therapy. Discordance with FFR-/iFR+ on the other hand, is characterised by low flow values, CFR, and CFC patterns similar to iFR+/FFR+ concordance that may benefit from percutaneous coronary intervention.

Kidney function deterioration is dependent on blood pressure levels: 11.2 year follow-up in diabetic patients.

There is little evidence of how blood pressure level over 10 years affects the decline of estimated glomerular filtration rate (eGFR) in diabetic patients. The Japanese primary prevention of atherosclerosis with aspirin for diabetes (JPAD) trial was a multicenter, randomized, clinical trial done from 2002 to 2008. After completion of the JPAD trial, we followed up the patients until 2019 as a cohort study. We defined late-stage kidney disease (LSKD) as eGFR < 30 ml/min/1.73 m2 or hemodialysis. Based on the mean value of systolic blood pressure (SBP) obtained average 7 times during the follow-up, we divided the patients into three groups: a high SBP group (n = 607, SBP ≥ 140 mm Hg); a moderate SBP group (n = 989, 140 > SBP ≥ 130 mm Hg); or a low SBP group (n = 913, SBP < 130 mm Hg). There was no significant deference in the mean eGFR among the high SBP, moderate SBP and low SBP groups on registration. The incidence rate of LSKD was significantly higher in the high SBP (HR 2.02, 95% CI 1.36-3.01) and moderate SBP (HR 1.54, 95% CI 1.07-2.20) groups than in the low SBP group (Log-Rank P = 0.0018). Cox proportional hazards model analysis revealed that the high SBP (HR, 1.57, P = 0.049) and moderate SBP (HR, 1.52, P = 0.037) were independent factors after adjustment for proteinuria ≥ ± , age ≥ 65 years, men, body mass index ≥ 24 kg/m2, duration of diabetes ≥ 7.0 years, statin usage, eGFR ≥ 60 ml/min/1.73 m2, hemoglobin A1c ≥ 7.2%, and smoking status. Our 11.2 year follow-up study demonstrated that mean SBP was independently associated with the progression to LSKD in diabetic patients. These findings may become new evidence that SBP less than 130 mm Hg is recommended for diabetic patients to prevent progression to LSKD.

Association Between Statins and Cancer Incidence in Diabetes: a Cohort Study of Japanese Patients with Type 2 Diabetes.

BACKGROUND: The antitumor effect of statins has been highlighted, but clinical study results remain inconclusive. While patients with diabetes are at high risk of cancer, it is uncertain whether statins are effective for cancer chemoprevention in this population. OBJECTIVE: This study evaluated the association between statins and cancer incidence/mortality in patients with type 2 diabetes. DESIGN: This study was a follow-up observational study of the Japanese Primary Prevention of Atherosclerosis with Aspirin for Diabetes (JPAD) trial, which was a randomized controlled trial of low-dose aspirin in Japanese patients with type 2 diabetes. PARTICIPANTS: This study enrolled 2536 patients with type 2 diabetes, age 30-85 years, and no history of atherosclerotic cardiovascular disease, from December 2002 until May 2005. All participants recruited in the JPAD trial were followed until the day of any fatal event or July 2015. We defined participants taking any statin at enrollment as the statin group (n = 650) and the remainder as the no-statin group (n = 1886). MAIN MEASURES: The primary end point was the first occurrence of any cancer (cancer incidence). The secondary end point was death from any cancer (cancer mortality). KEY RESULTS: During follow-up (median, 10.7 years), 318 participants developed a new cancer and 123 died as a result. Cancer incidence and mortality were 10.5 and 3.7 per 1000 person-years in the statin group, and 16.8 and 6.3 per 1000 person-years in the no-statin group, respectively. Statin use was associated with significantly reduced cancer incidence and mortality after adjustment for confounding factors (cancer incidence: adjusted hazard ratio [HR], 0.67; 95% CI, 0.49-0.90, P = 0.007; cancer mortality: adjusted HR, 0.60; 95% CI, 0.36-0.98, P = 0.04). CONCLUSIONS: Statin use was associated with a reduced incidence and mortality of cancer in Japanese patients with type 2 diabetes.

Per-Vessel Level Analysis of Fractional Flow Reserve and Instantaneous Wave-Free Ratio Discordance　- Insights From the AJIP Registry.

BACKGROUND: The per-vessel level impact of physiological pattern of disease on the discordance between fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) has not been clarified.Methods and Results:Using the AJIP registry, vessels with FFR/iFR discordance (133/671 [19.8%]) were analyzed. In the left anterior descending artery (LAD), physiologically diffuse disease, as assessed by pressure-wire pullback, was associated with FFR-/iFR+ (83.3% [40/48]), while physiologically focal disease was associated with FFR+/iFR- (57.4% [31/54]), significantly (P<0.0001). These differences were not significant in non-LAD (P=0.17). CONCLUSIONS: The impact of physiological pattern of disease on FFR/iFR discordance is more pronounced in the LAD.

Effect of QTU prolongation on hyperemic instantaneous wave-free ratio value: a prospective single-center study.

We hypothesized that in patients with QT prolongation, resistance might not decrease in the wave-free period, because QTU prolongation cannot be detected by instantaneous wave-free ratio (iFR) analysis software. We investigated whether corrected QTU (QTUc) prolongation affects the hyperemic iFR value. Forty-two consecutive patients with intermediate stenosis (≥ 50%) in the left anterior descending coronary artery (LAD) were analyzed. Fractional flow reserve (FFR) and hyperemic iFR were simultaneously and continuously recorded with intravenous adenosine triphosphate (ATP) and papaverine infusions. In 17 patients with stenosis in the proximal LAD, coronary flow was measured. Patients were divided into two groups according to the median absolute deviation of the QTUc by ATP administration/QTUc by papaverine administration. FFR, hyperemic iFR, and flow data were compared between each stimulus and group. Moreover, influences of pressure and electrocardiogram parameters on differences in iFR values under ATP and papaverine administration were compared between the following two groups (group 1: the absolute difference of hyperemic iFR values between ATP and papaverine administration is ≤ 0.05; group 2: that is > 0.05). The paired t test and t test were used in analysis. Hyperemic iFR values of patients under the use of papaverine were lower than those of patients under the use of ATP when QTUc was more prolonged by papaverine administration than by ATP administration (ATP 0.74 ± 0.14, papaverine 0.71 ± 0.15, P = 0.025). No significant differences were observed in the FFR value and flow data between the groups. Regarding QTU, QTUc, and QTUc by ATP/QTUc by papaverine, significant differences were observed between group 1 and group 2. Pressure parameters did not induce significant differences. QTUc prolongation induced by papaverine was associated with lower hyperemic iFR values. An iFR-based assessment might lead to inappropriate treatment of patients with QTUc prolongation.

Cutting Edge: Anti-TIM-3 Treatment Exacerbates Pulmonary Inflammation and Fibrosis in Mice.

Promising results of immune checkpoint inhibitors have indicated the use of immunotherapy against malignant tumors. However, they cause serious side effects, including autoimmune diseases and pneumonitis. T cell Ig and mucin domain (TIM)-3 is a new candidate immune checkpoint molecule; however, the potential toxicity associated with anti-TIM-3 treatment is unknown. In this study, we investigated the pathological contribution of anti-TIM-3 mAb in a bleomycin-induced lung inflammation and fibrosis model. Anti-TIM-3-treated mice showed more severe inflammation and peribronchiolar fibrosis compared with control IgG-treated mice. Anti-TIM-3 mAb was associated with increased numbers of myofibroblasts, collagen deposition, and TGF-ß1 production in lungs. TIM-3 expression was only detected on alveolar macrophages that protect against fibrosis by apoptotic cell clearance. Treatment with anti-TIM-3 mAb inhibited the phagocytic ability of alveolar macrophages in vivo, resulting in the defective clearance of apoptotic cells in lungs. In summary, anti-TIM-3 mAb treatment might cause pneumonitis and it should be used with caution in clinical settings.

Low-Dose Aspirin for Primary Prevention of Cardiovascular Events in Patients With Type 2 Diabetes Mellitus: 10-Year Follow-Up of a Randomized Controlled Trial.

BACKGROUND: The long-term efficacy and safety of low-dose aspirin for primary prevention of cardiovascular events in patients with type 2 diabetes mellitus are still inconclusive. METHODS: The JPAD trial (Japanese Primary Prevention of Atherosclerosis With Aspirin for Diabetes) was a randomized, open-label, standard care-controlled trial examining whether low-dose aspirin affected cardiovascular events in 2539 Japanese patients with type 2 diabetes mellitus and without preexisting cardiovascular disease. Patients were randomly allocated to receive aspirin (81 or 100 mg daily; aspirin group) or no aspirin (no-aspirin group) in the JPAD trial. After that trial ended in 2008, we followed up with the patients until 2015, with no attempt to change the previously assigned therapy. Primary end points were cardiovascular events, including sudden death, fatal or nonfatal coronary artery disease, fatal or nonfatal stroke, and peripheral vascular disease. For the safety analysis, hemorrhagic events, consisting of gastrointestinal bleeding, hemorrhagic stroke, and bleeding from any other sites, were also analyzed. The primary analysis was conducted for cardiovascular events among patients who retained their original allocation (a per-protocol cohort). Analyses on an intention-to-treat cohort were conducted for hemorrhagic events and statistical sensitivity. RESULTS: The median follow-up period was 10.3 years; 1621 patients (64%) were followed up throughout the study; and 2160 patients (85%) retained their original allocation. Low-dose aspirin did not reduce cardiovascular events in the per-protocol cohort (hazard ratio, 1.14; 95% confidence interval, 0.91-1.42). Multivariable Cox proportional hazard model adjusted for age, sex, glycemic control, kidney function, smoking status, hypertension, and dyslipidemia showed similar results (hazard ratio, 1.04; 95% confidence interval, 0.83-1.30), with no heterogeneity of efficacy in subgroup analyses stratified by each of these factors (all interaction P>0.05). Sensitivity analyses on the intention-to-treat cohort yielded consistent results (hazard ratio, 1.01; 95% confidence interval, 0.82-1.25). Gastrointestinal bleeding occurred in 25 patients (2%) in the aspirin group and 12 (0.9%) in the no-aspirin group (P=0.03), and the incidence of hemorrhagic stroke was not different between groups. CONCLUSIONS: Low-dose aspirin did not affect the risk for cardiovascular events but increased risk for gastrointestinal bleeding in patients with type 2 diabetes mellitus in a primary prevention setting. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00110448.

"J waves" induced after short coupling intervals: a manifestations of latent depolarization abnormality?

Aims: To confirm the presence of tachycardia-induced slur or notch in the terminal portion of the QRS complexes in a general patient population. Methods and results: A tachycardia-induced J wave was defined as a slur or notch in the terminal portion of the QRS complexes newly induced at short RR intervals during atrial premature contractions (APCs) or atrial electrical stimulation in the electrophysiological study (EPS). Twenty-three out of 2000 patients with general diseases were involved. All patients with aborted sudden cardiac death, ventricular fibrillation or a family history of sudden cardiac death were excluded. The mean age was 72 ± 9 years, and 11 patients were male (47.8%). When the RR interval was shortened from 821 ± 142 ms to 464 ± 52 ms in the conducted APCs (P < 0.0001), J waves became diagnostic (0.02 ± 0.03 mV to 0.20 ± 0.07 mV, P < 0.0001). J waves were confined to the inferior leads in 22 (95.7%) patients and were notched in 11 (47.8%) and slurred in 12 (52.2%) patients. The induction of J waves was accompanied by visible changes of the QRS morphology. When the post-APC RR interval was prolonged to 992 ± 305 ms (P = 0.0154 vs. baseline), the J waves were similar to baseline levels. During the EPS, J wave induction was confirmed during atrial stimulation. There were no characteristic clinical or ECG features in the patients with tachycardia-induced J waves. Conclusions: J waves can be newly induced by short RR intervals in a general patient population, and a conduction delay is the likely mechanism causing such J waves.

SiO2 and TiO2 nanoparticles synergistically trigger macrophage inflammatory responses.

Silicon dioxide (SiO2) nanoparticles (NPs) and titanium dioxide (TiO2) NPs are the most widely used inorganic nanomaterials. Although the individual toxicities of SiO2 and TiO2 NPs have been extensively studied, the combined toxicity of these NPs is much less understood. In this study, we observed unexpected and drastic activation of the caspase-1 inflammasome and production of IL-1ß in mouse bone marrow-derived macrophages stimulated simultaneously with SiO2 and TiO2 NPs at concentrations at which these NPs individually do not cause macrophage activation. Consistent with this, marked lung inflammation was observed in mice treated intratracheally with both SiO2 and TiO2 NPs. In macrophages, SiO2 NPs localized in lysosomes and TiO2 NPs did not; while only TiO2 NPs produced ROS, suggesting that these NPs induce distinct cellular damage leading to caspase-1 inflammasome activation. Intriguingly, dynamic light scattering measurements revealed that, although individual SiO2 and TiO2 NPs immediately aggregated to be micrometer size, the mixture of these NPs formed a stable and relatively monodisperse complex with a size of ~250 nm in the presence of divalent cations. Taken together, these results suggest that SiO2 and TiO2 NPs synergistically induce macrophage inflammatory responses and subsequent lung inflammation. Thus, we propose that it is important to assess the synergistic toxicity of various combinations of nanomaterials.

East asian variant of aldehyde dehydrogenase 2 is associated with coronary spastic angina: possible roles of reactive aldehydes and implications of alcohol flushing syndrome.

BACKGROUND: Coronary spastic angina (CSA) is a common disease among East Asians, including Japanese. The prevalence of alcohol flushing syndrome associated with deficient activity of the variant aldehyde dehydrogenase 2 (ALDH2*2) genotype is prevalent among East Asians. We examined whether CSA is associated with the ALDH2*2 genotype in Japanese. METHODS AND RESULTS: The study subjects consisted of 202 patients in whom intracoronary injection of acetylcholine was performed by angiography on suspicion of CSA (119 men and 83 women; mean age, 66.2±11.4 years). They were divided into CSA (112 patients) and control groups (90 patients). ALDH2 genotyping was performed by the direct application of the TaqMan polymerase chain reaction system on dried whole blood. Clinical and laboratory data were examined using conventional methods. The frequencies of male sex, ALDH2*2 genotype carriers, alcohol flushing syndrome, tobacco smoking, and the plasma level of uric acid were higher (P<0.001, P<0.001, P<0.001, P<0.001, and P=0.007, respectively) and the plasma high-density lipoprotein cholesterol levels were lower (P<0.001) in the CSA group than in the control group. The multivariable logistic regression analysis revealed that ALDH2*2 genotype and smoking were significantly associated with CSA (P<0.001 and P=0.024, respectively). CONCLUSIONS: East Asian variant ALDH2*2 genotypes and, hence, deficient ALDH2 activity were associated with CSA in Japanese. These data support further investigation of treatment targeting aldehydes for CSA.

Membrane Translocation and Organelle-Selective Delivery Steered by Polymeric Zwitterionic Nanospheres.

The majority of nanoparticles designed for cellular delivery of drugs and imaging agents enter the cell via endocytotic pathways leading to their entrapment in endosomes that present a robust barrier to further trafficking of the nanoparticles within the cells. A few materials, such as the cell penetrating peptides (CPPs), are known to enter cells not only via endocytosis, but also via translocation through the cell membrane into the cytoplasm, successfully bypassing the endosomes. We report here that random copolymers of 3-dimethyl(methacryloyloxyethyl)ammonium propanesulfonate and poly(ethylene glycol) methacrylate, p(DMAPS-ran-PEGMA), are internalized in cells primarily via translocation through the cell membrane rather than endocytosis. The properties of the polymers and their modes of uptake were investigated systematically by dynamic light scattering, confocal fluorescence microscopy, and flow cytometry. Using specific inhibitors of the cellular uptake machinery in a human cervical carcinoma cell line (HeLa), we show that these nontoxic synthetic polyzwitterions exist in cell media as self-assembled nanospheres that unravel as they adsorb on the plasma membrane and translocate through it. Conjugates of p(DMAPS-ran-PEGMA) with rhodamine B were delivered selectively to the mitochondria, whereas doxorubicin (Dox)-p(DMAPS-ran-PEGMA) conjugates were accumulated in both the nucleus and the mitochondria, effectively inducing apoptosis in HeLa cells. These findings suggest that the noncytotoxic and readily synthesized p(DMAPS-ran-PEGMA) can find applications as bioimaging tools and drug nanocarriers.

Fratricide of natural killer cells dressed with tumor-derived NKG2D ligand.

The natural killer group 2 membrane D (NKG2D) activating receptor plays crucial roles not only in host defense against tumors and viral infections, but also in autoimmune diseases. After NKG2D-mediated activation, Natural killer (NK) cells must be regulated to avoid potentially harmful reactivity. However, the negative regulation of these activated NK cells is poorly understood. Here, we reveal that the engagement of NKG2D by its ligand elicits not only target cell lysis, but also NK cell fratricide. Conventional mouse NK cells underwent cell death when cocultured with RMA cells expressing the NKG2D ligand retinoic acid early-inducible protein 1 (Rae-1), but not with RMA cells lacking MHC class I. NK cells from mice deficient for DAP10 and DAP12 or perforin did not undergo death, highlighting the importance of the NKG2D pathway for NK cell death. However, NKG2D does not transmit direct death signals in NK cells. Rather, the interaction between NKG2D and Rae-1 allowed NK cells to acquire tumor-derived Rae-1 by a membrane transfer process known as "trogocytosis," which was associated with clathrin-dependent NKG2D endocytosis. NK cells dressed with Rae-1 were lysed by neighboring NK cells through the NKG2D-induced perforin pathway in vitro and in vivo. These results provide the unique NKG2D function in negative regulation of activated NK cells.

NKG2D functions as an activating receptor on natural killer cells in the common marmoset (Callithrix jacchus).

The natural killer group 2 membrane D (NKG2D) receptor is an NK-activating receptor that plays an important role in host defense against tumors and viral infections. Although the marmoset is an important and reliable animal model, especially for the study of human-specific viral infections, functional characterization of NKG2D on marmoset NK cells has not previously been conducted. In the present study, we investigated a subpopulation of marmoset NK cells that express NKG2D and exhibit cytolytic potential. On the basis of their CD16 and CD56 expression patterns, marmoset NK cells can be classified into three subpopulations: CD16(+) CD56(-), CD16(-) CD56(+) and CD16(-) CD56(-) cells. NKG2D expression on marmoset CD16(+) CD56(-) and CD16(-) CD56(+) splenocytes was confirmed using an NKG2D ligand composed of an MHC class I chain-related molecule A (MICA)-Fc fusion protein. When marmoset splenocytes were cultured with IL-2 for 4 days, NKG2D expression was retained on CD16(+) CD56(-) and CD16(-) CD56(+). In addition, CD16(+) CD56(+) cells within the marmoset NK population appeared which expressed NKG2D after IL-2 stimulation. IL-2-activated marmoset NK cells showed strong cytolytic activity against K562 target cells and target cells stably expressing MICA. Further, the cytolytic activity of marmoset splenocytes was significantly reduced after addition of MICA-Fc fusion protein. Thus, NKG2D functions as an activating receptor on marmoset NK cells that possesses cytotoxic potential, and phenotypic profiles of marmoset NK cell subpopulations are similar to those seen in humans.

Papaverine-induced polymorphic ventricular tachycardia during coronary flow reserve study of patients with moderate coronary artery disease.

BACKGROUND: Papaverine is useful for evaluating the functional status of a coronary artery, but it may provoke malignant ventricular arrhythmia (VA). The aim of this study was to investigate the incidence, and clinical and ECG characteristics of patients with papaverine-induced VAs. METHODS AND RESULTS: The 182 consecutive patients underwent fractional flow reserve (FFR) measurement of 277 lesions. FFR was determined after intracoronary papaverine administration by standard procedures. The clinical and ECG characteristics were compared between patients with and without ventricular tachycardia (VT: ≥3 successive premature ventricular beats (PVBs), or ventricular fibrillation (VF)). After papaverine administration, the QTc interval, QTUc interval, and T-peak to U-end interval were prolonged significantly. Single PVBs on the T-wave or U-wave type developed in 29 patients (15.9%). Polymorphic VT (torsade de pointes) occurred in 5 patients (2.8%), and of those, VF developed in 3 patients (1.7%). No clinical and baseline ECG parameters were predictors for VT or VF except for sex and administration of papaverine into the left coronary artery. Excessive prolongation of QT (or QTU), T-peak to U-end intervals and giant T-U waves were found immediately prior to the ventricular tachyarrhythmias (VTAs), which were unpredictable from the baseline data. CONCLUSIONS: Intracoronary administration of papaverine induced fatal VTAs, although the incidence is rare. Excessive prolongation of the QT (and QTU) interval appeared prior to VTAs; however, they were unpredictable.