Changes in cerebrovascular disease-related deaths and their location during the COVID-19 pandemic in Japan

Objective

The COVID-19 pandemic placed an enormous strain on healthcare systems and raised concerns for delays in the management of patients with acute cerebrovascular events. In this study, we investigated cerebrovascular excess deaths in Japan.

Study design

Vital mortality statistics from January 2012 to May 2022 were obtained from the Japanese Ministry of Health, Labour and Welfare.

Methods

Using quasi-Poisson regression models, we estimated the expected weekly number of cerebrovascular deaths in Japan from January 2020 through May 2022 by place of death. Estimates were calculated for deaths in all locations, as well as for deaths in hospitals, in geriatric health service facilities, and at home. The age subgroups of ≥75 and <75 years were also considered. Weeks with a statistically significant excess of cerebrovascular deaths were determined when the weekly number of observed deaths exceeded the upper bound of 97.5% prediction interval.

Results

Excess deaths were noted in June 2021 and became more pronounced from February 2022 onwards. The trend was notable among those aged ≥75 years and for those who died in hospitals. With respect to the location of deaths, the excess was significant in geriatric health services facilities from April 2020 to June 2021, while no evidence of excess hospital deaths was observed during the same period.

Conclusions

Beginning in late 2021, excess cerebrovascular deaths coincided with the spread of the Omicron variant and may be associated with increased healthcare burden. In 2020, COVID-19 altered the geography of cerebrovascular deaths, with fewer people dying in hospitals and more dying in geriatric health service facilities and at home.

Cardiopulmonary arrest and in-hospital outcomes in young patients with acute myocardial infarction: insights from the Japanese nationwide registry

Background

Cardiopulmonary arrest (CPA) is the most serious presentation of acute myocardial infarction (AMI). However, the frequency and prognostic impact of CPA in young patients with AMI have been still unclear.

Objectives

This study aimed to characterize AMI in young patients who underwent primary percutaneous coronary intervention using large-scale nationwide all-comer registry data in Japan (J-PCI registry).

Methods

Data on risk factor profiles, clinical features, post-procedural complications, and in-hospital outcomes were reviewed within the J-PCI registry between 2014 and 2018.

Results

Among 213,297 patients with AMI, 23,985 (11.2%) were young (age, 20–49 years). Compared with the older group (age, 50–79 years; n=189,312), the young group included a higher number of men, smokers, patients with dyslipidemia, and patients with single-vessel disease, and a lower number of patients with hypertension and diabetes. Despite favorable clinical profiles, younger age was associated with a higher rate of presentation with CPA (Figure 1). Further, concomitant CPA was strongly associated with in-hospital mortality in the young group (Table 1).

Conclusions

Young patients with AMI presented a higher risk of CPA than older patients, which was strongly associated with in-hospital mortality.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): JSPS KAKENHI

Increasing the class of foundational medication for heart failure is associated with improved prognosis in hospitalized patients with heart failure with reduced or mildly reduced ejection fraction

Aim

To clarify the association between changes in the number of foundational medications for heart failure (FMHF) during hospitalization for worsening heart failure and post-discharge prognosis.

Methods and results

We retrospectively analyzed a combined dataset of three large-scale registries of hospitalized patients with heart failure in Japan (NARA-HF, WET-HF, and REALITY-AHF) and included patients already diagnosed with heart failure with reduced or mildly reduced left ventricular ejection fraction (HFr/mrEF) before admission. Patients were stratified by changes in the number of prescribed FMHF classes, namely angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, beta blockers, and mineralocorticoid receptor blockers, from admission to discharge. The primary endpoint was defined as the combined endpoint of heart failure rehospitalization and all-cause death within 1-year of discharge. The cohort consisted of 1,113 patients, and 482 combined endpoints were observed. In total, 413 (37.1%) patients were on increased FMHF (increased group), 607 (54.5%) remained unchanged (unchanged group), and 93 (8.4%) had a decreased number of FMHF (decreased group) at discharge compared to the time of admission. In multivariable analysis, the increased group was associated with a significantly lower incidence of the primary endpoint compared with the unchanged group (hazard ratio 0.56, 95% confidence interval 0.45–0.60; P&lt;0.001) and decreased group (hazard ratio 0.58, 95% confidence interval 0.40–0.84; P=0.004).

Conclusion

Increasing the number of FMHF cases during heart failure hospitalization is associated with a better prognosis in patients with HFr/mrEF.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): REALITY registry was funded by the Cardiovascular Research Fund of Japan.WET-HF registry was supported by a Grant-in-Aid for Young Scientists (Y.S. JSPS KAKENHI, 18K15860).

“Target Heart Rate” calculated aiming at zero overlap of mitral E and A waves is useful for prediction of long-term outcome for patients with heart failure and reduced ejection fraction

Background

Lower heart rate (HR) is associated with more favourable long-term outcome in patients with heart failure with reduced ejection fraction (HFrEF). However, an optimal threshold of HR remains unclear. Targeted HR (THR), defined by echocardiographic deceleration time (DCT) to eliminated overlap of E and A waves, may aid in risk stratification of HFrEF patients.

Purpose

In this study, we aimed to clarify the impact of on long-term clinical outcome in patients with HFrEF.

Methods

In the multicenter WET-HF registry, 4000 consecutive patients hospitalized for acute decompensated HF (ADHF) were registered between 2006 and 2017. Among them, the patients with EF ≥40% or a history of atrial fibrillation were excluded. THR was calculated based on their DCT value measured in compensated HF phase during the index admission. The following formula was applied; THR (bpm)=93 - 0.13 × deceleration time (DCT, msec). A total of 876 patients with HFrEF were included in the present analysis (age: 72 [60–81], male: 69%) and the patients were divided into the 2 groups of HR at discharge ≤ THR (L group) and &gt; THR (H group). The primary endpoint (PE) was defined as the composite of all-cause death and ADHF re-admission.

Results

Compared to the H group, the L group showed higher prevalence of males (74% vs. 66%, P=0.025) with higher body mass index (BMI, 23.2 vs. 22.2, P=0.016), hemoglobin (Hb, 12.9 vs. 12.4, P=0.031), albumin (Alb, 3.7 vs. 3.6, P=0.039) and larger left atrial diameter (LAD, 44 mm vs. 41 mm, P=0.002) and tricuspid regurgitation pressure gradient (TRPG, 29 mmHg vs. 27 mmHg, P=0.012). Age, estimated glomerular filtration rate (eGFR), LVEF (29% vs. 30%, P=NS) and E/e' (17.7 vs. 16.8, P=NS) were similar for both groups. At discharge, HR was lower in L group (66 [60–71] bpm vs. 80 [74–86] bpm, P&lt;0.001), albeit there were no significant differences in b-blocker prescription (90% vs. 85%, P=0.069) or its dose (3.75 [1.25–7.25] mg vs. 2.5 [1.25–5] mg, P=0.11).

In the survival analysis, the L group showed a significantly lower rate of PE (P=0.03), whereas there was no significant difference in the incidence of PE between the patients with HR at discharge ≥70 bpm and &lt;70 bpm (P=NS).

Multivariate Cox hazard analysis showed that HR at discharge ≤ THR was an independent predictor of PE (hazard ratio 0.67 [0.46–0.97], P=0.037), even after adjusting for confounding factors including age, sex, BMI, Hb, Alb, and b-blocker prescription, whereas HR at discharge &lt;70 bpm was not (hazard ratio 0.94 [0.65–1.33], P=0.71).

Conclusion

THR was associated with long-term outcomes in patients with HFrEF after acute decompensation, suggesting that it may aid in tailored treatment for HR reduction in these patients.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Quality and clinical outcomes of primary percutaneous coronary intervention after ST-segment elevation myocardial infarction: a population density analysis of a Japanese nationwide registry

Background

Despite progress in acute myocardial infarction (MI) treatment, data on geographical disparities in its care remain limited.

Purpose

We aimed to assess the discrepancy by population density (PD) on the quality and clinical outcomes of patients with primary percutaneous coronary intervention (PCI) after ST-segment elevation MI (STEMI).

Methods

The J-PCI registry is a prospective procedural registry conducted by the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) to assure the quality of delivered care. Between January 2014 and December 2018, 209,521 patients underwent PCI for STEMI in 1,126 institutes. Population of administrative municipal-level districts was determined through the complete population census. The patients were divided into tertiles according to the PD of the PCI institution location (low: &lt;951.7/km2, n=69,797; middle: 951.7–4,729.7/km2, n=69,750; high: ≥4,729.7/km2, n=69,974).

Results

Patients treated in high PD administrative districts were younger (low: 69.1±12.9, middle: 68.7±12.9, high: 68.0±13.1) and likely to be male (low: 75.6%, middle: 76.0%, high: 76.6%). No significant correlation was observed between PD and door-to-balloon time (DTB: regression coefficients: 0.036 per 1000 people/km2, 95% CI: −0.232 to 0.304, P=0.79). Patients treated in low PD areas had higher crude in-hospital mortality rates than those treated in high PD areas (low: 2.89%, middle: 2.60%, high: 2.38%; P&lt;0.001). Moreover, PD and in-hospital mortality had a significantly inverse association, before and after adjusting for baseline characteristics (crude odds ratio [OR]: 0.983 per 1,000/km2, 95% confidence interval [CI]: 0.973–0.992, P&lt;0001; adjusted OR: 0.980 per 1,000/km2, 95% CI: 0.964–0.996, P=0.01, respectively). Higher PD districts had more operators per institute (low: 6, interquartile range [IQR] 3–10; middle: 7, IQR 3–13; high: 8, IQR 5–13, P&lt;0.001), suggesting an inverse association with in-hospital mortality (OR: 0.992, 95% CI: 0.986–0.999, P=0.03).

Conclusions

Marked geographical inequality was observed in immediate case fatality; patients treated in population-dense areas had a lower in-hospital mortality than those treated in less dense areas. Variation in the number of operators per institute, rather than traditional quality indicators (e.g. DTB) may explain the difference in in-hospital mortality.

Funding Acknowledgement

Type of funding source: None

Effect of air pollution on acute heart failure hospitalization differ across specific heart failure populations

Introduction

Several report showed the association between ambient air pollution including particular matter under 2.5um (PM2.5) and increasing rate of hospitalization for heart failure. However, these report analyzed mainly cross-sectional, epidemiological data, thus the reports regarding association between vulnerability to PM2.5 and specific populations in acute heart failure (AHF) were scarce.

Purpose

1. To analyze the association between air pollution and rate of hospitalization for AHF

2. To analyze whether the vulnerability to air pollution differ between specific populations in AHF. Methods

A case-cross over analysis was conducted to 4980 consecutive patients registered for multicenter acute heart failure registry in 2017 in our city Japan. This registry enrolled patients transferred to cardiovascular care unit (80 institutions) via emergency medical services across our city area. Logistic regression analysis were conducted to estimate percentage changes in the rate of acute heart failure hospitalization associated with per 1μg/m3 PM2.5 concentration increase. We also conducted subgroup analysis for patients stratified by age, gender, comorbidities, left ventricular ejection fraction, and clinical scenario.

Results

An increase in 1 μg/m3 PM2.5 concentration corresponded to 2.9% (95% CI 1.2–4.6%) increase in AHF hospitalization. Patients with age younger than 75, without prior heart failure hospitalization, without history of hypertension, without anemia, and with reduced ejection fraction were more susceptible to increase in PM2.5 concentration (Figure).

Conclusions

Increase in PM2.5 concentration was associated with increased rate of AHF hospitalization. Effect of PM2.5 may differ across specific AHF subpopulations.

Figure 1

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Tokyo Metropolitan Government

P5411Prognostic communication with hospitalized heart failure patients; the patients' perspective

Background

Informing heart failure (HF) patients about their prognosis is an important part of clinical management, particularly at the time of hospitalization. Current European Society of Cardiology guidelines recommend communicating this information to HF patients at the time of hospitalization and with any change in clinical status. However, little is known about actual patient preferences, understanding, and attitudes towards prognostic communication with their treating physicians.

Methods

We surveyed 113 consecutive hospitalized HF patients in a single university hospital. We assessed patient understanding of prognosis (likelihood of survival beyond 2 years), and compared patient expectations to model predictions. Model-predicted 2-year survival rate was calculated by the Seattle Heart Failure Model (SHFM). We also assessed patient preferences for information disclosure using the Prognosis and Treatment Perception Questionnaire (PTPQ). The PTPQ assesses patient beliefs regarding 1) the importance of knowing about prognosis, 2) the importance of knowing about treatment option, and 3) frequency of having a conversation about prognosis during the hospital stay.

Results

Enrolled patients were predominantly male (65.5%), with a mean age of 73.6±9.6 years and mean left ventricular ejection fraction was 46.2±15.4%. Median SHFM-estimated 2-year survival rate was 89.2% (interquartile range: 83.8–92.9%). Overall, patient understanding about prognosis was suboptimal. Among patients with a guarded 2-year survival (SHFM <90%: N=60), 44% reported that their likelihood of 2-year survival was >90% (Figure; red box). However, among patients with favorable 2-year survival (>90%: N=53), 38% reported a likelihood of <90% (Figure; blue box). Regarding treatment options, most patients (98%) desired to learn as many details as possible. Responses varied with regard to information on individual prognosis; whereas 51% wanted to know more about prognosis than their present status alone, a significant number (28%) of subjects answered “never” or “less often” to a query on the frequency of discussion about prognosis. Patient preference for more information about prognosis was associated with female sex (odds ratio [OR]: 2.52; 95% confidence interval [CI]: 1.12–5.69), fewer symptoms of depression (1-point increase on Patient Health Questionnaire-2, OR: 0.66; 95% CI: 0.49–0.87), and previous stroke (OR: 2.92; 95% CI: 1.04–8.19), but not other social/demographic or clinical factors (e.g., age, education, caregiver support, HF phenotype and severity, and other comorbid conditions).

Figure 1

Conclusions

There were substantial discrepancies in patient understanding of prognosis and in desire for more information from physicians. Interventions to improve prognostic understanding are warranted for HF patients, and hospitalization for HF could represent an opportunity for optimization.

P684Long-term outcomes in patients with cancer undergoing percutaneous coronary intervention: analysis from a Japan multicenter registry

Background

Cancer and cardiovascular disease (CVD) is the most common cause of death in developed countries, and substantial overlap exist in their medical care. However, the detailed and updated information on outcome of cancer patients with cardiovascular disease (CVD), particularly in clinically significant coronary artery disease (CAD) remain unknown.

Purpose

We sought to describe the prevalence and long-term outcomes of cancer patients undergoing percutaneous coronary intervention (PCI), which has become a coronerstone in the management of CVD.

Methods

Patient data extracted from a regional prospectiveprocedure-based multicenter registry for PCI was analyzed. A total of 4,455 patients who underwent PCI at 15 hospitals within metropolitan Tokyo from September 2008 to 2012 were followed for 2 years. “Active” cancer patient was defined as having a history of cancer not cured or in remission. We analyzed in acute and stable presentation.The occurrence of clinical outcomes was assessed via Kaplan-Meier survival curve, and Cox-regression hazard model to adjust for known clinical predictors.

Results

Within the studied patients, 173 (3.9%) had a concomitant “active” cancer at the time of intervention. There was a significant difference between the patients with and without active cancer in each situation. In stable presentation, cancer group were older, lower BMI, frequently had silent ischemia, COPD and cerebrovascular/peripheral disease, and less often had dyslipidemia compared with non-cancer group. In acute presentation, cancer group were older, frequently had COPD, CKD, peripheral disease and history of HF compared with non-cancer group. The prescription rate of RAAS inhibitor was lower in the cancer group than in the non-cancer group in acute presentation. Notably, in both acute and stable presentation, these patients had significantly higher risk of all-cause mortality (HR 8.01: 95%, p<0.001 and HR5.53: 95%, p<0.001, respectively), and they were also at higher risk of major cardo- and cerebrovascular events (MACCE; HR2.38, p<0.001, HR2.33, p=0.001), when referenced to non-cancer patients after 2 year of follow-up.

Conclusion

Cancer patient was present in 3.9% of all PCI patients and was strongly associated with both non-cardiac and cardiac adverse events.

P6531Evidence-practice gap in the preprocedural risk assessment for contrast-induced acute kidney injury

Background

Contrast-induced acute kidney injury (CI-AKI) is one of the frequently encountered and costly complications after percutaneous coronary intervention (PCI). Clinical practice guidelines strongly recommend that PCI patients should universally undergo preprocedural assessment for the risk of CI-AKI, and the contrast volume (CV) should be minimized to an achievable level, particularly among the high AKI risk patients. However, data on the CV use based on the comprehensive preprocedural risk assessment is still lacking.

Purpose

Our study aimed to 1) assess the impact of CV increase with the incidence of AKI among high AKI risk patients, and 2) retrospectively evaluate the used CV based on the preprocedural comprehensive risk assessment for patients undergoing PCI within multicenter longitudinal registry.

Methods

Between 2009 and 2018, 22,373 patients underwent PCI in 14 participating facilities, and consecutive patient data was registered. AKI was defined as a >0.3mg/dl absolute or >1.5-fold relative increase in post-PCI creatinine or new initiation of dialysis, based on the Acute Kidney Injury Network criteria. The post-procedural creatinine was defined as the highest value within 30 days after the indexed procedure. Congruent with the National Cardiovascular Data Registry (NCDR) definition, if more than 1 post-procedural creatinine level was measured, the highest value was used for determining AKI. We divided the patients into four groups according to quartile of NCDR AKI risk scores.

Results

Mean age of the patients were 68.7±11.1 years, and 79.1% were male. Mean CV use was 161.4±74.8ml. The incidence of CI-AKI was 8.9%, and was particularly high among high AKI risk patients (21.1%); CV (per 1ml linear increase) was directly associated with the occurrence of AKI (OR: 1.002 per unit in CV; 95% CI: 1.001–1.003; P<0.001) in these patients. CV during PCI decreased with the progression of chronic kidney disease (CKD), but it did not alter by the overall NCDR AKI risk score (Figure). After multivariable adjustment, CV was predicted by stage of CKD (−13.68ml; 95% CI: −12.05 to −15.30ml; P<0.001), but not by the value of pre-procedure prediction score (NCDR AKI risk score, P=0.575).

CV according to CKD/NCDR AKI risk score

Conclusions

Higher CV was directly associated with the occurrence of AKI among higher AKI risk patients. However, CV use was largely influenced by the stage of renal disease, and not with overall patient risk presented by contemporary risk scores. Our results have identified an important evidence-practice gap and emphasizes the importance of total preprocedural assessment to minimize CV and prevent subsequent AKI.

Acknowledgement/Funding

KAKENHI (16KK0186, 16H05215, 25460630, 25460777), Bayer, Daiichi Sankyo, Bristol-Myers Squibb, Teikoku Seiyaku, Sumitomo Dainippon, AstraZeneka, Pfizer

P2622Use of intravenous vasodilators in patients hospitalized with acute heart failure: insights from Tokyo cardiovascular care unit network database

Background

Despite recommendations from clinical practice guidelines, there is scant evidence confirming the effects of vasodilators on clinical outcomes in patients with acute heart failure (AHF).

Purpose

We sought to investigate the effects of intravenous vasodilators on clinical outcomes and to identify the potential patient populations that would benefit from its use.

Methods

Data of 26 212 consecutive patients urgently hospitalized for AHF between 2009 and 2015 were extracted from a multicenter data registration system (Tokyo Cardiovascular Care Unit Network Database, including 72 institutions within the Tokyo metropolitan area in Japan). Patients who did not present with typical AHF episodes, including those without pulmonary congestion on physical and/or chest X-ray and serum B-type natriuretic peptide level <500 pg/ml, as well as those who had hypotension and/or hypoperfusion (systolic blood pressure [SBP] <100 mmHg) as dominant presentation, were excluded. Propensity scores were calculated with multiple imputation and 1:1 matching performed between patients with and without vasodilators. The primary endpoint was in-hospital mortality and the secondary endpoints were length of intensive/cardiovascular care unit (ICU/CCU) stay and hospital stay.

Results

Overall, 8 863 patients were included in the present analysis; they were predominantly male (57%) with a median age of 79 (interquartile range: 70–86) years. Compared with the group without vasodilator use, the vasodilator group had higher SBPs and heart rates and higher frequency of assisted ventilation use, but lower frequency of intravenous diuretics use. After propensity score matching, there were no significant differences in in-hospital mortality rates (7.8% vs. 8.9% in patients without vasodilators, p=0.16) or in length of ICU/CCU stay (5.8 days vs. 5.4 days, p=0.44) and hospital stay (22.7 days vs. 23.8 days, p=0.22) between the groups. However, in subgroup analyses, favorable impacts of vasodilator use on in-hospital mortality were observed among patients who had higher SBPs and among those who had no atrial fibrillation upon admission (Figure). In addition, vasodilators were likely to be more effective in AHF patients with SBP increasing; while levels below 140 mmHg of SBP appeared to be associated with an increased risk for mortality among patients treated with vasodilators compared with those without vasodilators.

Figure 1

Conclusions

In patients with AHF, vasodilator use was not universally associated with improved in-hospital outcomes; however, its effect was dependent of individual clinical presentation. Detailed phenotyping might aid tailoring of treatment strategies for patients with AHF.

Acknowledgement/Funding

the Tokyo Metropolitan Government

B-type natriuretic peptide levels are decreased by reducing dietary salt intake in patients with compensated heart failure with preserved ejection fraction

BACKGROUND

Dietary salt restriction is believed to be a mainstay in the management of patients with heart failure. However, the effect of salt intake on heart failure has not been well evaluated in outpatient medical practice.

AIMS

The aim of the present study was to assess the hypothesis that B-type natriuretic peptide (BNP) level, as an objective marker of heart failure, is associated with salt intake in patients with heart failure.

METHODS

One hundred and thirteen consecutive patients with mild compensated heart failure (77 ± 10 years old, 51 female) were included. We estimated dietary salt intake by the concentration of sodium and creatinine in spot urine. We measured BNP at the time of urine sampling and assessed the relationship between the % changes in BNP levels (%ΔBNP) and the changes in the estimated daily salt excretion (ΔNaCl) during the follow-up period.

RESULTS

The baseline median BNP level was 150 (interquartile range: 83-263) pg/mL and the estimated daily salt excretion was 162 ± 45 mmol/day. There was a positive correlation between %ΔBNP and ΔNaCl (r = 0.61, P < 0.01). Multiple regression analysis revealed that %ΔBNP was associated with ΔNaCl (P < 0.01), but not with changes in systolic blood pressure and bodyweight.

CONCLUSIONS

Changes in BNP levels were associated with changes in the estimated daily salt excretion in outpatients with compensated heart failure. Salt restriction may be beneficial for the management of patients with heart failure.

Effect of (6R)- and (6S)-tetrahydrobiopterin on L-3,4-dihydroxyphenylalanine (DOPA) formation in NRK fibroblasts transfected with human tyrosine hydroxylase type 2 cDNA

l-erythro-5,6,7,8-Tetrahydrobiopterin (BH(4)), which is the cofactor of aromatic amino acid hydroxylases, plays an important role in the biosyntheses of monoamine neurotransmitters. BH(4) exists as natural (6R)- and unnatural (6S)-isomers. In our previous reports, only (6R)-isomer significantly stimulated cofactor activity for tyrosine, tryptophan and phenylalanine hydroxylases (TH, TPH, PAH) in whole animals or in tissue slices. In this study we have compared the in situ cofactor activity on TH between natural (6R)- and unnatural (6S)-isomers in clonal cells. We have transfected human TH type 2 cDNA into the normal rat kidney (NRK) fibroblasts. These cells expressed TH protein, but had neither DOPA decarboxylase (DDC) nor BH(4). Thus, TH activity was observed only in the presence of exogenous BH(4). We compared the difference in in situ DOPA formation by TH activity in the presence of (6R)- or (6S)-BH(4) in the human TH-transfected cells. The effect of exogenous BH(4) was also compared between (6R)- and (6S)-isomers in rat pheochromocytoma PC12h cells, which contained approximately 100 ?M endogenous (6R)-BH(4). The rate of uptake of both BH(4) isomers into these cells increased in proportion to the pterin cofactor concentrations in the incubation medium up to 400 ?M but was nearly saturated at 1 mM BH(4). TH-transfected NRK fibroblasts formed DOPA only in the presence of exogenously added (6R)- or (6S)-BH(4) dose-dependently and released DOPA into the medium. At a saturating concentration of 1 mM, (6R)-BH(4) was approximately three times as active as (6S)-BH(4). In contrast, in PC12h cells which contained endogenous (6R)-BH(4) (approximately 100 ?M), exogenous (6R)-BH(4) activated DOPA formation maximally at 500 ?M about 10-fold, while (6S)-BH(4) activated it only slightly, about 2.5-fold. These results suggest that (6S)-isomer has lower cofactor activity with TH in the cells than (6R)-isomer. This TH transfected fibroblasts should be useful to assess cofactor activities of tetrahydropteridines in the cell.

Risk stratification of coronary revascularization patients by using clinical and angiographic data

AIM

Patients undergoing coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) are still at a substantial risk of death after their procedures. A core group of preoperative and preprocedural risk factors and conditions contributes the majority of inherent mid- and long-term mortality risk in these patients. Therefore, we sought to develop a classification tree model as a practical and user-friendly method of predicting mid-term survival after coronary revascularization procedures.

METHODS

We retrospectively analyzed data from a single, large-volume institution. Specifically, we examined all-cause three-year mortality in 3387 consecutive patients with multivessel or single proximal left anterior descending coronary artery disease who underwent either PCI with stenting or CABG.

RESULTS

Recursive partitioning indicated that the best single predictor of death within three years was a history of heart failure (HF), followed by a proximal left circumflex artery (pLCX) lesion and age greater than 65 years for patients with and without a history of HF, respectively. With these variables, patients were readily stratified into low-, intermediate-, and high-risk groups whose risks of death over three years ranged from 2.3% to 36.2%. Among patients with a history of HF, pLCX stenosis was an independent predictor of mid-term mortality after adjustment for other known risk factors (hazard ratio, 1.46; 95% CI, 1.04-2.03).

CONCLUSION

The constructed risk stratification scheme stratified patients into groups at low, intermediate, and high risk of death within three years. Stenosis of the pLCX seems to be an important prognostic factor for patients with a history of HF.

The origin and cell lineage of microglia: new concepts

Despite intense study, the precise origin and cell lineage of microglia, the resident mononuclear phagocytes of the nervous system, are still a matter for debate. Unlike macroglia (astrocytes and oligodendrocytes) and neurons, which are derived from neuroectoderm, microglial progenitors arise from peripheral mesodermal (myeloid) tissue. The view still commonly held is that tissue-resident mononuclear phagocytes (including microglia) are derived from circulating blood monocytes and these take up residence late in gestation and postnatally. However, microglial progenitors colonise the nervous system primarily during embryonic and fetal periods of development. Recent evidence indicates differences between the lineage of mononuclear phagocytes during the embryonic and fetal period from that in the neonate and adult-mononuclear phagocytes that take up residence within tissues are derived from a lineage of myeloid cells that is independent of the monocyte lineage. Our own findings on the development and differentiation of microglial progenitors, taken together with findings by other investigators, and in the context of the heterogeneity between myeloid differentiation in the fetus and in the adult, support the view that microglia are derived prenatally from mesodermal progenitors that are distinct from monocytes. Furthermore, microglial progenitors colonise the nervous system via extravascular routes initially. These findings challenge the concept that resident microglia in the nervous system are derived from circulating blood monocytes. Work is still underway to establish the tissue of origin and lineage of microglial progenitors in vivo. This information is critical not only from a developmental perspective, but significantly from a therapeutic viewpoint, as (i) the unique property of microglial progenitors to colonise the nervous system from the periphery allows these cells to be exploited as a biological and non-invasive means for cell therapy by delivering genes to the nervous system (microglial engraftment), and (ii) there are indications that microglial progenitors are specifically able to home to the nervous system. Use of microglial progenitors for therapeutic purposes becomes feasible only if the origin and cell lineage of these microglial progenitors are known and these cells can be isolated and manipulated in vitro (i.e., to express specific trophic factors) prior to therapeutic transfer (e.g., intravenously) in vivo. In this paper, we shall briefly consider the existing concepts on the origin and lineage of microglial progenitors and discuss new hypotheses in the light of emerging data that suggest clear differences between fetal and adult ontogeny of myeloid cells.

The mutation in the ATP-binding region of JAK1, identified in human uterine leiomyosarcomas, results in defective interferon-gamma inducibility of TAP1 and LMP2

The presentation of human leukocyte antigens (HLA) class I requires the coordinated expression of numerous components involved in antigen presentation. Tumor cells may alter the antigen presentation by HLA class I, allowing them to evade antitumor immunity. In many cases, the lack of antigen presentation can be attributed to the downregulation of genes needed for antigen processing, such as the transporters associated with antigen processing (TAP) 1, and the proteasomal component, low molecular weight proteins (LMP) 2. The TAP1 and LMP2 genes are transcribed from a shared bidirectional promoter containing an interferon (IFN)-gamma-response factor element; thus, the IFN-gamma-signal strongly induces both TAP1 and LMP2 expression. Low molecular weight proteins2-deficient mice exhibited the development of uterine leiomyosarcomas. Here, the differential responsiveness to IFN-gamma of the SKN human uterine leiomyosarcomas cell line was investigated. We now identify the G871E mutation in the ATP-binding region of Janus kinases 1, suggesting that the loss of TAP1 and LMP2 induction is a defect in the earliest steps of the IFN-gamma-signal pathway, resulting in the inability of SKN cells to upregulate the antigen-processing pathway. Understanding the mechanisms by which these tumors circumvent cytokine signalling, thereby evading antitumor-specific immunity, would greatly aid the efficacy of immunotherapy for treating uterine leiomyosarcomas.

Visualization of microglia in living tissues using Iba1-EGFP transgenic mice

Microglia are thought to play important roles not only in repairing injured tissue but in regulating neuronal activity, and visualizing the cells is very useful as a means of further investigating the function of microglia in vivo. We previously cloned the ionized calcium-binding adaptor molecule 1 (Iba1) gene, which is expressed selectively in microglia/microphages. To generate new transgenic mice to visualize microglia with enhanced green fluorescent protein (EGFP), we here constructed a plasmid carrying EGFP cDNA under control of the Iba1 promoter. This construct was injected into C57B/6 mouse zygotes, and the Iba1-EGFP transgenic line was developed. Fluorescent in-situ hybridization analysis revealed that the Iba1-EGFP transgene was located on chromosome 11D. No obvious defects were observed during development or in adulthood, and the EGFP fluorescence remained invariant over the course of at least four generations. Judging from the immunoreactivity with anti-Iba1 antibody, all EGFP-positive cells in the adult brain were ramified microglia. In the developing transgenic embryos, EGFP signals were detected as early as embryonic Day 10.5. The most prominent EGFP signals were found in forebrain, spinal cord, eye, foreleg, yolk sac, liver, and vessel walls. At postnatal Day 6, clear EGFP signals were observed in the supraventricular corpus callosum, known as "fountain of microglia", where ameboid microglia migrate into the brain parenchyma and mature into ramified microglia. Iba1-EGFP transgenic mice thus permit observation of living microglia under a fluorescence microscope and provide a useful tool for studying the function of microglia in vivo.

Distribution of the galectin-1 mRNA in the rat nervous system: its transient upregulation in rat facial motor neurons after facial nerve axotomy

Galectin-1 is a member of the animal lectin family that displays conserved consensus sequences and similar carbohydrate binding specificities. Recent analyses revealed that galectin-1 plays an important role in the process of nerve regeneration. We analyzed the topological expression of galectin-1 mRNA in adult rat nervous system. Galectin-1 mRNA was predominantly observed in the cell bodies of neurons such as oculomotor nucleus (III), trochlear nucleus (IV), trigeminal motor nucleus (V), abducens nucleus (VI), facial nucleus (VII), hypoglossal nucleus (XII), red nucleus, and locus ceruleus. Neurons in pineal gland and dorsal root ganglia expressed galectin-1 mRNA. We next tested whether the axotomy of facial nerve altered the expression of galectin-1 mRNA in motor neurons. In the adult rats, the axotomy of facial nerve induced transient upregulation of galectin-1 mRNA around 6 h after axotomy. These results indicate that galectin-1 may play roles in the early event of the nerve injury and regeneration through the transient change of its expression level.

Widespread activation of the brainstem preceding the recruiting rhythm in human epilepsies

The excitability change of the brainstem was investigated before and during the conspicuous epileptic discharge in six patients with generalized convulsive seizures. The discharge consisted of a short duration of recruiting rhythm, which was considered equivalent to the seizure discharge on electroencephalogram. The excitability of the brainstem was measured with the parameters (amplitude and area) of component waves (wave-III and -V) of brainstem auditory evoked potentials. The theoretical background of the analysis is that brainstem auditory evoked potentials are 'far-field' potentials, by which they convey the information on the activity change of the brainstem even during the paroxysmal discharge within the cortex. The excitability of both the ventral (parameters of wave-III) and the dorsal brainstem (parameters of wave-V) exhibited a synchronized change (activation-inactivation). They were enhanced from -2.4+/-0.4 s, reaching the maxima before the onset of the seizure discharge, and decayed corresponding to the emergence of the recruiting rhythm. The results suggest the possibility that the widespread (ventral and dorsal) and synchronized activation of the brainstem triggers the seizure discharge in human generalized epilepsy. During the widespread activation of the brainstem, both the thalamus and the cortex probably undergo a suppressed inhibitory state through the cholinergic activation, precipitating the seizure discharge.

Induction of CHOP and apoptosis by nitric oxide in p53-deficient microglial cells

Excessive nitric oxide (NO) has been implicated in neurotoxicity after stresses such as ischemia. NO toxicity is generally thought to be mediated by the DNA damage-p53 pathway or mitochondrial dysfunction. We investigated the mechanism of NO toxicity by using murine microglial MG5 cells established from p53-deficient mice. When MG5 cells were exposed to bacterial lipopolysaccharide plus interferon-gamma, mRNA and protein for inducible NO synthase (iNOS) were markedly induced, and apoptosis occurred. Under these conditions, we found that mRNA and protein for CHOP/GADD153, a C/EBP family transcription factor which is involved in endoplasmic reticulum (ER) stress-induced apoptosis, are induced. iNOS mRNA was induced 2 h after treatment, whereas CHOP mRNA began to increase at 6 h with a time lag. CHOP mRNA was also induced by NO donors S-nitroso-N-acetyl-DL-penicillamine (SNAP) or NOC18, or a peroxynitrite generator 3-(4-morpholinyl)-sydnonimine hydrochloride (SIN-1). Bip/GRP78, an ER chaperone which is known to be induced by ER stress, was also induced by SNAP or SIN-1, indicating that NO causes ER stress. These results suggest that NO-induced apoptosis in MG5 cells occurs through the ER stress pathway involving CHOP, but is independent of p53.

Establishment of CHO cell lines expressing four N-methyl-D-aspartate receptor subtypes and characterization of a novel antagonist PPDC

To develop an assay system that allows the N-methyl-D-aspartate (NMDA) receptor subtype-selective antagonistic potency of drugs, we have established Chinese hamster ovary cell lines expressing the four NMDA receptor subtypes (GluRepsilon1/zeta1-GluRepsilon4/zeta1) heat-indelibly. Using these clonal cells, we found that a novel antagonist, (1S,2R)-1-phenyl-2[(S)-1-aminopropyl]-N,N-diethylcyclopropanecarboxamide, was less selective for the GluRepsilon1/zeta1: the IC(50) values for the GluRepsilon1/zeta1-GluRepsilon4/zeta1 were 41.7, 13.3, 12.6 and 11.5 microM, respectively, while two well-known antagonists, DL-2-amino-5-phosphonovaleric acid and ifenprodil, showed the known potency and selectivity for each subtype. Thus, the established clonal cells are of use in characterizing the pharmacological properties of drugs that act on NMDA receptors.

Nitric oxide inhibits the proliferation of murine microglial MG5 cells by a mechanism involving p21 but independent of p53 and cyclic guanosine monophosphate

We investigated the effect of nitric oxide (NO) on the proliferation of microglial MG5 cells established from p53-deficient mice. Cells were treated with bacterial lipopolysaccharide and interferon-gamma, and expression of inducible NO synthase (iNOS) and p21/waf1, a cyclin-dependent kinase inhibitor protein which is a critical downstream effector of p53, was investigated by RNA blot and immunoblot analyses. iNOS mRNA was induced 2 h after treatment and increased with time up to 24 h. p21 mRNA was expressed at a low level in untreated cells and increased with a kinetics similar to that for iNOS mRNA. iNOS and p21 proteins were also induced. An NO donor SNAP induced p21 mRNA and protein. SNAP inhibited incorporation of [(3)H]thymidine in MG5 cells in a dose-dependent manner. 8-Bromo-cGMP neither induced p21 mRNA nor inhibited [(3)H]thymidine incorporation. These results suggest that NO inhibits the proliferation of MG5 cells by induction of p21, which occurs independent of p53 and cGMP.

Mechanisms underlying extracellular ATP-evoked interleukin-6 release in mouse microglial cell line, MG-5

Microglia play various important roles in the CNS via the synthesis of cytokines. The ATP-evoked production of interleukin-6 (IL-6) and its intracellular signals were examined using a mouse microglial cell line, MG-5. ATP, but not its metabolites, produced IL-6 in a concentration-dependent manner. Although ATP activated two mitogen-activated protein kinases, i.e. p38 and extracellular signal-regulated protein kinase, only p38 was involved in the IL-6 induction. However, the activation of p38 was not sufficient for the IL-6 induction because 2'- and 3'-O-(4-benzoylbenzoyl) ATP, an agonist to P2X7 receptors, failed to produce IL-6 despite the fact that it activated p38. Unlike in other cytokines in microglial cells, P2Y rather than P2X7 receptors seem to have a major role in the IL-6 production by the cells. The ATP-evoked IL-6 production was attenuated by Gö6976, an inhibitor of Ca(2+)-dependent protein kinase C (PKC). The P2Y receptor responsible for these responses was insensitive to pertussis toxin (PTX) and was linked to phospholipase C. Taken together, ATP acting on PTX-insensitive P2Y receptors activates p38 and Ca(2+)-dependent PKC, thereby resulting in the mRNA expression and release of IL-6 in MG-5. This is a novel pathway for the induction of cytokines in microglia.

[Regulation of microglial cell function by ATP]

Accumulated evidence suggests that extracellular ATP functions occur in neurons and glial cells in the nervous systems. Besides well-documented roles as a neurotransmitter or neuromodulator, ATP has also been demonstrated to have effects on glial cells. Reports have shown that ATP stimulates microglia to release various biologically active substances, such as interleukin-1 beta, tumor necrosis factor-alpha, and plasminogen. Microglial cell death was also demonstrated after stimulation with high-dose ATP. Although these responses were known to occur, via P2X7, we have recently found that ATP and ADP induced the formation of membrane ruffles and chemotaxis through Gi/o-coupled P2Y receptors. Taken together, it is suggested that two distinct P2X and P2Y receptor subtypes are involved in the diverse function of microglia in both physiological and pathological states.

Iba1 is an actin-cross-linking protein in macrophages/microglia

Iba1 is a 17-kDa EF hand protein that is specifically expressed in macrophages/microglia and is upregulated during the activation of these cells. When exposed to macrophage colony-stimulating factor (M-CSF), microglia cell line MG5 immediately produces intense membrane ruffles in which Iba1 accumulates together with filamentous actin. In this study, we investigated the physical interaction between Iba1 and actin by centrifugation assay and electron microscopic examination and showed that Iba1 possesses actin-binding and -cross-linking activities. Inhibitory mutant Iba1 that suppresses M-CSF-induced membrane ruffling had lost the actin-cross-linking activity, and it inhibited the cross-linking activity of intact Iba1. These results indicate that Iba1 is a macrophage/microglia-specific actin-cross-linking protein essential for M-CSF-induced membrane ruffling.

Neurotrophin secretion from cultured microglia

Because microglia have been suggested to produce neurotrophins, we tested this ability in vitro. Rat primary microglia were found to constitutively secrete a limited amount of brain-derived neurotrophic factor (BDNF), but nerve growth factor (NGF) and neurotrophin-3 (NT-3) were undetectable in the conditioned medium. Stimulation of the cells with lipopolysaccharide (LPS) increased BDNF secretion, and induced NGF secretion. As a first step to examine this regulation system, the association of protein kinase C (PKC) was pharmacologically analyzed. A PKC activator, phorbol-12-myristate-13-acetate, enhanced the secretion of BDNF. Pre-treatment of microglia with a PKC inhibitor, bisindolylmaleimide, suppressed LPS-stimulated BDNF secretion as well as the constitutive one. These results suggest that the PKC signaling cascade is closely associated with BDNF secretion. Among PKC isoforms, PKCalpha probably plays a role in BDNF secretion, based on the results of experiments using a specific PKC activator, 1-oleoyl-2-acetyl-sn-glycerol, and a specific PKC inhibitor, Gö 6976, and by immunoblotting. Taken together, these findings suggest that the secretion of BDNF from microglia is regulated through PKCalpha-associated signal transduction mechanism.

Impaired microglial activation in the brain of IL-18-gene-disrupted mice after neurovirulent influenza A virus infection

Knockout of the interleukin-18 (IL-18) gene predisposed mice to impaired clearance of neurovirulent influenza A virus-infected neurons from the brain. In wild-type mice, IL-18 molecule-producing microglia/macrophages emerged in virally attacked regions as early as day 3 after infection. Microglial transformation into macrophages culminated at day 7 to 9, with upregulated expression of Iba1, a novel calcium-binding protein that controls phagocytic functions of microglia/macrophages. In IL-18-/- mice, microglial transformation was interrupted with reduced Iba1 expression. Interferon-gamma (IFN-gamma)-immunopositive neurons appeared in and around virally invaded regions in wild-type mice, peaking in number at day 7, whereas such cells were barely detected in IL-18-/- mice. Stereotaxic microinjection of recombinant IFN-gamma triggered microglial transformation in IL-18-/- mice and upregulated Iba1 expression, leading to effective eradication of virally infected neurons. Collectively, these results suggest that IL-18 plays a key role in activating microglial functions directed against the influenza virus infection by inducing neuronal IFN-gamma in the brain parenchyma.

Molecular characterization of mammalian homologues of class C Vps proteins that interact with syntaxin-7

Vesicle-mediated protein sorting plays an important role in segregation of intracellular molecules into distinct organelles. Extensive genetic studies using yeast have identified more than 40 vacuolar protein sorting (VPS) genes involved in vesicle transport to vacuoles. However, their mammalian counterparts are not fully elucidated. In this study, we identified two human homologues of yeast Class C VPS genes, human VPS11 (hVPS11) and human VPS18 (hVPS18). We also characterized the subcellular localization and interactions of the protein products not only from these genes but also from the other mammalian Class C VPS homologue genes, hVPS16 and rVPS33a. The protein products of hVPS11 (hVps11) and hVPS18 (hVps18) were ubiquitously expressed in peripheral tissues, suggesting that they have a fundamental role in cellular function. Indirect immunofluorescence microscopy revealed that the mammalian Class C Vps proteins are predominantly associated with late endosomes/lysosomes. Immunoprecipitation and gel filtration studies showed that the mammalian Class C Vps proteins constitute a large hetero-oligomeric complex that interacts with syntaxin-7. These results indicate that like their yeast counterparts, mammalian Class C Vps proteins mediate vesicle trafficking steps in the endosome/lysosome pathway.