Aya Shiraki

• Doctor of Medicine
• Professor (Associate) at Saga University

Use of dipeptidyl peptidase-4 (DPP4) inhibitor in some clinical trials might have caused heart failure (HF), leading to increased hospitalizations. The aim of the present study was to determine whether linagliptin has any effect on chronic dilated HF, and its underlying mechanisms. Physiologic and pathologic studies were conducted on heart/muscle-s...

Background It was reported that glucagon-like peptide-1 has cardio-protective effects, however, the occurrence of heart failure was increased with DPP4 inhibitor in some large clinical trials. Purpose The purpose of the present work was to clarify whether DPP4 inhibitor had any effects on chronic, dilated heart failure and to identify the mechanis...

Background Sodium-glucose cotransporter 2 (SGLT2) inhibitors have been demonstrated to have beneficial effects on HF in large clinical trials; however, the mechanisms remain to be elucidated. The aim of this study was to clarify the mechanisms by which empagliflozin, one of SGLT2 inhibitors, affects heart failure. Method and results Eight-week-old...

Myocardial infarction is still a life-threatening disease, even though its prognosis has been improved through the development of percutaneous coronary intervention and pharmacotherapy. In addition, heart failure due to remodeling after myocardial infarction requires lifelong management. The aim of this study was to develop a novel treatment suppre...

Introduction: Vaccination therapy has long-lasting effects and solves medication non-adherence. However, vaccination therapy on myocardial infarction (MI) has not been developed. Epoxyeicosatrienoic acids (EETs) play an important role in cardio-protective mechanisms through angiogenesis. Here, we developed a soluble epoxide hydrolase (sEH) peptide...

Background In-hospital bleeding is associated with poor prognosis in patients with acute myocardial infarction (AMI). We sought to investigate whether a combination of pre-procedural blood tests could predict the incidence of in-hospital major bleeding in patients with AMI. Methods and results A total of 1684 consecutive AMI patients who underwent...

Background/Introduction Sodium-glucose cotransporter 2 (SGLT2) inhibitors have been reported to have beneficial effects on heart failure in large clinical trials; however, the underlying mechanism is still unclear. Purpose The purpose of this study is to elucidate the mechanism of cardioprotective effect of empagliflozin in heart failure. Methods...

Objective Glucagon-like peptide-1 analog and DPP4 inhibitors are reported to have cardio-protective properties against atherosclerosis and cardiac function in vitro and in vivo, however, concerns that incretin -related drug can increase the risk of heart failure also have been arisen. Therefore, the purpose of this study was to elucidate the effect...

Background: Glucagon-like peptide-1 (GLP-1) reduces cardiovascular events in diabetic patients; however, its counter-protective effects have also been suggested in patients with heart failure and the clear explanation for its mechanisms have not yet been offered. Methods: The effects of GLP-1 analog on cardiac function and energy metabolism, esp...

2-Cl-C.OXT-A (COA-Cl) is a novel nucleic acid analogue that promotes tube-forming activity of human umbilical vein endothelial cells (HUVEC) through vascular endothelial growth factor (VEGF). The development of coronary collateral circulation is critical to rescue the ischemic myocardium and to prevent subsequent irreversible ischemic injury. We ev...

Aim: Recently, calcium channel blockers (CCBs) have been reported to reduce atherosclerosis with anti-inflammatory or antiatherosclerotic effects in vivo. It is well established that monocytes and macrophages play important roles in promoting atherosclerosis. However, the effects of CCBs on macrophage activation remain unclear. The aim of this stu...

Aim: The aim of the present study was to assess the efficacy and safety of sitagliptin in elderly patients with type 2 diabetes mellitus. Methods: A total of 188 patients were enrolled who had type 2 diabetes mellitus with poor glycemic profiles (hemoglobin A1c [HbA1c] ≥6.2%). Patients were assigned to one of three age groups (<65, 65-74 and ≥75...

Statin-related myopathy (SRM) is a clinically important adverse reaction. Recent pharmacogenetic research, mainly in non-Asian populations, have indicated clinical relevance of some of genetic biomarkers to SRM, but predictive markers for SRM in Asian populations including Japanese has not yet been established. This study was aimed to identify clin...

Objective: Manganese superoxide dismutase (MnSOD) is an important antioxidant enzyme affected in heart/muscle-specific MnSOD-deficient mice (H/M-SOD2-/-), which develop progressive congestive heart failure and exhibit pathology typical of dilated cardiomyopathy. Design and Method: In this study we investigated the beneficial effects of epigallocate...

Background: Manganese superoxide dismutase (MnSOD) is an important antioxidant enzyme affected in heart/muscle-specific MnSOD-deficient mice (H/M-SOD2(-/-)), which develop progressive congestive heart failure and exhibit pathology typical of dilated cardiomyopathy. Methods: In this study we investigated the beneficial effects of epigallocatechin...

Background: An excessive inflammatory response after myocardial infarction (MI) increases myocardial injury. The toll-like receptor (TLR)-4 is activated by the recognition of endogenous ligands and is proinflammatory when there is myocardial tissue injury. The apoptosis inhibitor of the macrophage (AIM) is known to provoke an efflux of saturated f...

Background and aims: Pentraxin-3 (PTX3) reportedly has protective roles in atherosclerosis and myocardial infarction, and is a useful biomarker of vascular inflammation. However, the detailed functions of PTX3 in inflammation are yet to be elucidated. This study aimed to investigate the function of PTX3 in macrophages. Methods: PMA-treated THP-1 ce...

Introduction: The persistent inflammation response after myocardial infarction increases myocardial injury, and causes heart failure due to cardiac dysfunction and remodeling. TLR-4 was activated by the recognition of not only pathogen-associated molecular patterns but also endogenous ligands and it serves as a proinflammatory function in circumsta...

Background: Obstructive sleep apnea (OSA) is characterized by repetitive intermittent hypoxia and reoxygenation during sleep with elevated oxidative stress and promotes the development of atherosclerosis, as demonstrated by vascular dysfunction and chronic inflammation. An increased neutrophil to lymphocyte ratio (NLR) has been recognized to be a...

The purpose of this study was to elucidate the effects of glimepiride on the levels of biomarkers related to cardiovascular regulation in patients with type 2 diabetes mellitus.Methods and results: Thirty-four patients with type 2 diabetes received glimepiride for 24 weeks. Significant decreases in the levels of glyceraldehyde-derived advanced glyc...

Background: Recently, it has been reported that some calcium-channel blockers (CCB) reduced atherosclerosis with anti-inlammatory or anti-atherosclerotic effects in vivo. It is well known that monocytes or macrophages play important roles in atherosclerosis. However, the effects of CCB on macrophage activation remain unclear. The aim of the current...

Background: Glucagon-like Peptide 1 (GLP-1), one of incretin hormones, has been reported to increase positive inotropic activity in cardiac myocytes and protect against myocardial injury. However, the mechanisms involved are not fully understood. We assessed the hypothesis that GLP-1 has protective effects against inlammation and oxidative stress o...

Glucagon-like peptide 1 (GLP-1), one of the incretin hormones, has been reported to increase positive inotropic activity in cardiac myocytes and protect against myocardial injury. However, the effects upon endothelial cells and the mechanisms involved are not fully understood. We assessed the hypothesis that GLP-1 has protective effects against inf...

Excessive production of airway mucus is a cardinal feature of bronchial asthma and chronic obstructive pulmonary disease (COPD) and contributes to morbidity and mortality in these diseases. IL-13, a Th2-type cytokine, is a central mediator in the pathogenesis of bronchial asthma, including mucus overproduction. Using a genome-wide search for genes...