Comparing In-Hospital Outcomes for Acute Myocardial Infarction Patients in High-Volume Hospitals Performing Primary Percutaneous Coronary Intervention vs. Regional General Hospitals.

BACKGROUND: It has been reported that patients with acute myocardial infarction (AMI) transferred to low-volume primary percutaneous coronary intervention (PCI) hospitals (<115/year) in low population density areas experience higher in-hospital mortality rates. This study compared in-hospital outcomes of patients admitted to high-volume primary PCI hospitals (≥115/year) with those for other regional general hospitals.Methods and Results: Retrospective analysis was conducted on data obtained from 2,453 patients with AMI admitted to hospitals in Iwate Prefecture (2014-2018). Multivariate analysis revealed that the in-hospital mortality rate of AMI among patients in regional general hospitals was significantly higher than among patients in high-volume hospitals. However, no significant difference in mortality rate was observed among patients with ST-elevation myocardial infarction (STEMI) undergoing primary PCI. Although no significant difference was found in the in-hospital mortality rate of patients with Killip class I STEMI, significantly lower in-hospital mortality rates were observed in patients admitted in high-volume hospitals for Killip classes II, III, and IV. CONCLUSIONS: Although in-hospital outcomes for patients with STEMI undergoing primary PCI were similar, patients with heart failure or cardiogenic shock exhibited better in-hospital outcomes in high-volume primary PCI hospitals than those in regional general hospitals.

Role of Toll like receptor signaling pathway in ischemic coronary artery disease.

Inflammatory process plays a fundamental role in ischemic coronary artery disease (CAD) in terms of both the etiology of atherosclerosis and the pathophysiology of CAD. In particular, chronic inflammation plays a key role in coronary artery plaque instability and subsequent occlusive thrombosis. It is therefore important to clarify the mechanism underlying the activation of the immune response in the pathogenesis of CAD. Currently 10 toll-like receptors (TLRs) have been reported in mammalian species, and these appear to recognize distinct pathogen-associated molecular patterns controlling innate immune responses. In recent studies, signaling of two forms of human TLR (TLR2 and TLR4) has been shown to be involved in the pathogenesis of CAD, establishing a key link between the progression of coronary atherosclerosis and immune response to both foreign pathogens and endogenously generated inflammatory ligands. A better understanding of TLR signal may provide a novel therapeutic agent for the treatment of CAD. This review summarizes the relationship between the pathogenesis of ischemic coronary artery disease and the human TLR system.

Local expression of Toll-like receptor 4 at the site of ruptured plaques in patients with acute myocardial infarction.

Several reports suggest that a chronic inflammatory process plays a key role in coronary artery plaque instability and subsequent occlusive thrombosis. In a previous study, we found that TLR4 (Toll-like receptor 4) mediates the synthesis of cytokines in circulating monocytes of patients with AMI (acute myocardial infarction); however, it remains unclear whether TLRs are expressed at the site of the ruptured plaque in these patients. The aim of the present study was to determine whether TLR2 and TLR4 are expressed at the site of ruptured plaques in patients with AMI and to compare this with systemic levels. The study included 62 patients with AMI, 20 patients with SA (stable angina) and 32 subjects with a normal coronary angiogram (control). Local samples from the site of the ruptured plaque were taken from patients with AMI using aspiration catheterization. Systemic blood samples from the aorta were taken from patients with AMI and SA and controls. Systemic levels of TLR2 and TLR4 were higher in patients with AMI than in patients with SA and controls. In patients with AMI, local TLR4 levels were higher than systemic levels. There was no significant difference in TLR2 levels between local and systemic samples. TLR4 immunostaining was positive in infiltrating macrophages in ruptured plaque material. Cardiac events were observed in 16 patients with AMI at the time of the 6-month follow-up study. Local and systemic levels of TLR4 were higher in patients with AMI with cardiac events than in those without. These results indicate an increase in monocytic TLR4 expression not only in the systemic circulation, but also at the site of plaque rupture. In conclusion, expression of both systemic and local plaque TLR4 may be one of the mechanisms responsible for the pathogenesis of AMI.

Association between oxidative DNA damage and telomere shortening in circulating endothelial progenitor cells obtained from metabolic syndrome patients with coronary artery disease.

Metabolic syndrome (MS) induces an increase in oxidative stress and may be an important contributory factor for coronary artery disease (CAD). Telomere shortening of endothelial progenitor cells (EPCs) may be the key factor in endothelial cell senescence. The rate of telomere shortening is highly dependent on cellular oxidative damage. This study analyzed the relationship between telomere shortening and oxidative DNA damage in EPCs obtained from CAD patients with MS and without MS. We analyzed circulating EPCs in peripheral blood obtained from 57 patients with CAD (acute myocardial infarction [AMI], n=26; stable angina pectoris [AP], n=31) and 21 age-matched healthy subjects (control). Telomere length and telomerase activity were significantly lower in CAD patients than in controls, and were lower in AMI patients than in AP patients. Oxidative DNA damage was higher in CAD patients compared with controls, and oxidative DNA damage in AMI patients was also higher than in AP patients. There was a negative correlation between telomere length and oxidative DNA damage. Telomere length and telomerase activity were lower in CAD patients with MS than in those without MS. Oxidative DNA damage in CAD patients with MS was higher than in those without MS. In our in vitro study, oxidative treatments induced telomere shortening and decrease in telomerase activity of EPCs. These results suggest that EPC telomere shortening via increased oxidative DNA damage may play an important role in the pathogenesis of CAD. In addition, MS may be related to increased oxidative DNA damage and EPC telomere shortening.

Association between toll-like receptor 8 expression and adverse clinical outcomes in patients with enterovirus-associated dilated cardiomyopathy.

BACKGROUND: In recent reports, human toll-like receptor (TLR) 8 mediates the antiviral response by recognizing single-stranded RNA. The inflammatory response against enteroviral (EV) RNA replication may play an important role in dilated cardiomyopathy (DCM). The purpose of this study was to determine whether TLR8 was expressed with EV replication in patients with enterovirus-associated DCM. METHODS: Reverse transcriptase-polymerase chain reaction analysis was performed to screen the detection of myocardial EV RNA in 198 consecutive patients with DCM. Seventy-two EV RNA-positive patients with DCM and 20 control samples constituted the study population of the present study. Levels of TLR8 and myeloid differentiation factor (MyD) 88 adaptor protein mRNA and EV RNA (plus- and minus-strand RNAs) were measured by real-time RT-PCR. Immunohistochemistry was performed to identify the cellular source of these molecules. RESULTS: Toll-like receptor 8 and MyD88 mRNA levels were higher in patients with DCM than in controls (P < .001). Immunostainings of TLR8, MyD88, and EV protein showed localization of these proteins in cardiac myocytes in patients with DCM. After a mean follow-up of 426 days, clinical outcomes (development of heart failure n = 11, cardiac death n = 3) were associated with increased levels of TLR8 and MyD88 (P < .05). Multivariate analysis showed that TLR8 (relative risk 3.2, 95% CI 1.6-6.2) was a strong predictor of heart failure and cardiac death after adjustment for baseline characteristics. CONCLUSION: Toll-like receptor 8 and MyD88 expressions may be involved in the immune response to EV replication in enterovirus-associated DCM. In addition, TLR8 may provide important prognostic information in patients with enterovirus-associated DCM.

Elevated circulating levels of heat shock protein 70 are related to systemic inflammatory reaction through monocyte Toll signal in patients with heart failure after acute myocardial infarction.

BACKGROUND: Recent studies have shown that heat shock protein (HSP) 70 may serve as a "damage signal" to the immune system and could be the endogenous ligand for Toll-like receptor (TLR) 4 mediating synthesis of inflammatory cytokines. AIMS: To explore the relationship between circulating HSP70 levels and activation of monocyte TLR4 and myocardial damage after AMI. METHODS AND RESULTS: This study examined circulating HSP70 and monocyte TLR4 levels in 52 patients with AMI and 20 controls, and analyzed ex vivo inflammatory cytokine productions using HSP70-stimulated monocytes. Circulating HSP70 levels were higher in AMI patients on day 1 after onset than in controls and remained elevated in AMI patients 14 days after onset. HSP70 levels were positively correlated with monocyte TLR4, plasma interleukin-6 and tumor necrosis factor-alpha levels in AMI patients. HSP70 levels 14 days after onset were higher in AMI patients with heart failure (n=15) than in those without heart failure. In our in vitro study, HSP70-stimulated monocytes resulted in dose-dependent TLR4 expression and release of inflammatory cytokines. TLR4 antibody inhibited inflammatory cytokines release. CONCLUSIONS: Elevated circulating levels of HSP70 may be involved in TLR4 signal-mediated immune response and the progression of heart failure after AMI.

Activated toll-like receptor 4 in monocytes is associated with heart failure after acute myocardial infarction.

Peripheral monocytosis may affect the development of heart failure (HF) after acute myocardial infarction (AMI). Activated toll-like receptor (TLR) 4 in monocytes plays an important role in the synthesis of proinflammatory cytokines. We examined TLR4 expression in monocytes, which may be a possible source of proinflammatory cytokines in AMI. Sixty-five patients with AMI and 20 healthy subjects (HS) were studied. Monocytes were isolated from peripheral blood on days 1 and 14 after the onset of AMI. TLR4 levels in monocytes were measured using real-time RT-PCR and flow cytometry. Generation capacity was evaluated by TLR4 levels and cytokine concentrations in the culture medium with lipopolysaccharide (LPS) stimulation. On day 1 after onset, baseline levels of TLR4 and plasma proinflammatory cytokines, notably IL-6 and TNF-alpha, were higher in AMI patients than in HS. These levels remained elevated in AMI patients 14 days after onset. Generation capacities of TLR4 and proinflammatory cytokines (IL-2, IL-6, IL-8, IL-10, GM-CSF and TNF-alpha) were increased in AMI patients compared to HS. LPS-stimulated TLR4 levels were positively correlated with IL-6 and TNF-alpha levels in AMI patients. Baseline TLR4 levels and plasma proinflammatory cytokine (IL-6, GM-CSF and TNF-alpha) levels were higher in AMI patients with HF (n = 22) than in those without HF. Generation capacities of TLR4 and proinflammatory cytokines (IL-6, GM-CSF and TNF-alpha) were greater in AMI patients with HF than in those without HF. Activation of TLR4 through a myocytic inflammatory reaction is associated with HF after AMI. These observations suggest that TLR4 signaling in monocytes may play a role in the development of HF after AMI.